Long live Qt!

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diff --git a/src/3rdparty/sqlite/sqlite3.c b/src/3rdparty/sqlite/sqlite3.c
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+/******************************************************************************
+** This file is an amalgamation of many separate C source files from SQLite
+** version 3.5.9.  By combining all the individual C code files into this 
+** single large file, the entire code can be compiled as a one translation
+** unit.  This allows many compilers to do optimizations that would not be
+** possible if the files were compiled separately.  Performance improvements
+** of 5% are more are commonly seen when SQLite is compiled as a single
+** translation unit.
+**
+** This file is all you need to compile SQLite.  To use SQLite in other
+** programs, you need this file and the "sqlite3.h" header file that defines
+** the programming interface to the SQLite library.  (If you do not have 
+** the "sqlite3.h" header file at hand, you will find a copy in the first
+** 5638 lines past this header comment.)  Additional code files may be
+** needed if you want a wrapper to interface SQLite with your choice of
+** programming language.  The code for the "sqlite3" command-line shell
+** is also in a separate file.  This file contains only code for the core
+** SQLite library.
+**
+** This amalgamation was generated on 2008-05-14 16:20:58 UTC.
+*/
+#define SQLITE_CORE 1
+#define SQLITE_AMALGAMATION 1
+#ifndef SQLITE_PRIVATE
+# define SQLITE_PRIVATE static
+#endif
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+/************** Begin file sqliteInt.h ***************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Internal interface definitions for SQLite.
+**
+** @(#) $Id: sqliteInt.h,v 1.704 2008/05/13 13:27:34 drh Exp $
+*/
+#ifndef _SQLITEINT_H_
+#define _SQLITEINT_H_
+
+/*
+** Include the configuration header output by 'configure' if we're using the
+** autoconf-based build
+*/
+#ifdef _HAVE_SQLITE_CONFIG_H
+#include "config.h"
+#endif
+
+/************** Include sqliteLimit.h in the middle of sqliteInt.h ***********/
+/************** Begin file sqliteLimit.h *************************************/
+/*
+** 2007 May 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** 
+** This file defines various limits of what SQLite can process.
+**
+** @(#) $Id: sqliteLimit.h,v 1.8 2008/03/26 15:56:22 drh Exp $
+*/
+
+/*
+** The maximum length of a TEXT or BLOB in bytes.   This also
+** limits the size of a row in a table or index.
+**
+** The hard limit is the ability of a 32-bit signed integer
+** to count the size: 2^31-1 or 2147483647.
+*/
+#ifndef SQLITE_MAX_LENGTH
+# define SQLITE_MAX_LENGTH 1000000000
+#endif
+
+/*
+** This is the maximum number of
+**
+**    * Columns in a table
+**    * Columns in an index
+**    * Columns in a view
+**    * Terms in the SET clause of an UPDATE statement
+**    * Terms in the result set of a SELECT statement
+**    * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
+**    * Terms in the VALUES clause of an INSERT statement
+**
+** The hard upper limit here is 32676.  Most database people will
+** tell you that in a well-normalized database, you usually should
+** not have more than a dozen or so columns in any table.  And if
+** that is the case, there is no point in having more than a few
+** dozen values in any of the other situations described above.
+*/
+#ifndef SQLITE_MAX_COLUMN
+# define SQLITE_MAX_COLUMN 2000
+#endif
+
+/*
+** The maximum length of a single SQL statement in bytes.
+**
+** It used to be the case that setting this value to zero would
+** turn the limit off.  That is no longer true.  It is not possible
+** to turn this limit off.
+*/
+#ifndef SQLITE_MAX_SQL_LENGTH
+# define SQLITE_MAX_SQL_LENGTH 1000000000
+#endif
+
+/*
+** The maximum depth of an expression tree. This is limited to 
+** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might 
+** want to place more severe limits on the complexity of an 
+** expression.
+**
+** A value of 0 used to mean that the limit was not enforced.
+** But that is no longer true.  The limit is now strictly enforced
+** at all times.
+*/
+#ifndef SQLITE_MAX_EXPR_DEPTH
+# define SQLITE_MAX_EXPR_DEPTH 1000
+#endif
+
+/*
+** The maximum number of terms in a compound SELECT statement.
+** The code generator for compound SELECT statements does one
+** level of recursion for each term.  A stack overflow can result
+** if the number of terms is too large.  In practice, most SQL
+** never has more than 3 or 4 terms.  Use a value of 0 to disable
+** any limit on the number of terms in a compount SELECT.
+*/
+#ifndef SQLITE_MAX_COMPOUND_SELECT
+# define SQLITE_MAX_COMPOUND_SELECT 500
+#endif
+
+/*
+** The maximum number of opcodes in a VDBE program.
+** Not currently enforced.
+*/
+#ifndef SQLITE_MAX_VDBE_OP
+# define SQLITE_MAX_VDBE_OP 25000
+#endif
+
+/*
+** The maximum number of arguments to an SQL function.
+*/
+#ifndef SQLITE_MAX_FUNCTION_ARG
+# define SQLITE_MAX_FUNCTION_ARG 100
+#endif
+
+/*
+** The maximum number of in-memory pages to use for the main database
+** table and for temporary tables.  The SQLITE_DEFAULT_CACHE_SIZE
+*/
+#ifndef SQLITE_DEFAULT_CACHE_SIZE
+# define SQLITE_DEFAULT_CACHE_SIZE  2000
+#endif
+#ifndef SQLITE_DEFAULT_TEMP_CACHE_SIZE
+# define SQLITE_DEFAULT_TEMP_CACHE_SIZE  500
+#endif
+
+/*
+** The maximum number of attached databases.  This must be between 0
+** and 30.  The upper bound on 30 is because a 32-bit integer bitmap
+** is used internally to track attached databases.
+*/
+#ifndef SQLITE_MAX_ATTACHED
+# define SQLITE_MAX_ATTACHED 10
+#endif
+
+
+/*
+** The maximum value of a ?nnn wildcard that the parser will accept.
+*/
+#ifndef SQLITE_MAX_VARIABLE_NUMBER
+# define SQLITE_MAX_VARIABLE_NUMBER 999
+#endif
+
+/* Maximum page size.  The upper bound on this value is 32768.  This a limit
+** imposed by the necessity of storing the value in a 2-byte unsigned integer
+** and the fact that the page size must be a power of 2.
+*/
+#ifndef SQLITE_MAX_PAGE_SIZE
+# define SQLITE_MAX_PAGE_SIZE 32768
+#endif
+
+
+/*
+** The default size of a database page.
+*/
+#ifndef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE 1024
+#endif
+#if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+/*
+** Ordinarily, if no value is explicitly provided, SQLite creates databases
+** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
+** device characteristics (sector-size and atomic write() support),
+** SQLite may choose a larger value. This constant is the maximum value
+** SQLite will choose on its own.
+*/
+#ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
+#endif
+#if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+
+/*
+** Maximum number of pages in one database file.
+**
+** This is really just the default value for the max_page_count pragma.
+** This value can be lowered (or raised) at run-time using that the
+** max_page_count macro.
+*/
+#ifndef SQLITE_MAX_PAGE_COUNT
+# define SQLITE_MAX_PAGE_COUNT 1073741823
+#endif
+
+/*
+** Maximum length (in bytes) of the pattern in a LIKE or GLOB
+** operator.
+*/
+#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
+# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
+#endif
+
+/************** End of sqliteLimit.h *****************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/* Disable nuisance warnings on Borland compilers */
+#if defined(__BORLANDC__)
+#pragma warn -rch /* unreachable code */
+#pragma warn -ccc /* Condition is always true or false */
+#pragma warn -aus /* Assigned value is never used */
+#pragma warn -csu /* Comparing signed and unsigned */
+#pragma warn -spa /* Suspicous pointer arithmetic */
+#endif
+
+/* Needed for various definitions... */
+#define _GNU_SOURCE
+
+/*
+** Include standard header files as necessary
+*/
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+
+/*
+** A macro used to aid in coverage testing.  When doing coverage
+** testing, the condition inside the argument must be evaluated 
+** both true and false in order to get full branch coverage.
+** This macro can be inserted to ensure adequate test coverage
+** in places where simple condition/decision coverage is inadequate.
+*/
+#ifdef SQLITE_COVERAGE_TEST
+SQLITE_PRIVATE   void sqlite3Coverage(int);
+# define testcase(X)  if( X ){ sqlite3Coverage(__LINE__); }
+#else
+# define testcase(X)
+#endif
+
+
+/*
+** The macro unlikely() is a hint that surrounds a boolean
+** expression that is usually false.  Macro likely() surrounds
+** a boolean expression that is usually true.  GCC is able to
+** use these hints to generate better code, sometimes.
+*/
+#if defined(__GNUC__) && 0
+# define likely(X)    __builtin_expect((X),1)
+# define unlikely(X)  __builtin_expect((X),0)
+#else
+# define likely(X)    !!(X)
+# define unlikely(X)  !!(X)
+#endif
+
+
+/*
+** These #defines should enable >2GB file support on Posix if the
+** underlying operating system supports it.  If the OS lacks
+** large file support, or if the OS is windows, these should be no-ops.
+**
+** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
+** system #includes.  Hence, this block of code must be the very first
+** code in all source files.
+**
+** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
+** on the compiler command line.  This is necessary if you are compiling
+** on a recent machine (ex: RedHat 7.2) but you want your code to work
+** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2
+** without this option, LFS is enable.  But LFS does not exist in the kernel
+** in RedHat 6.0, so the code won't work.  Hence, for maximum binary
+** portability you should omit LFS.
+**
+** Similar is true for MacOS.  LFS is only supported on MacOS 9 and later.
+*/
+#ifndef SQLITE_DISABLE_LFS
+# define _LARGE_FILE       1
+# ifndef _FILE_OFFSET_BITS
+#   define _FILE_OFFSET_BITS 64
+# endif
+# define _LARGEFILE_SOURCE 1
+#endif
+
+
+/*
+** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
+** Older versions of SQLite used an optional THREADSAFE macro.
+** We support that for legacy
+*/
+#if !defined(SQLITE_THREADSAFE)
+#if defined(THREADSAFE)
+# define SQLITE_THREADSAFE THREADSAFE
+#else
+# define SQLITE_THREADSAFE 1
+#endif
+#endif
+
+/*
+** Exactly one of the following macros must be defined in order to
+** specify which memory allocation subsystem to use.
+**
+**     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
+**     SQLITE_MEMDEBUG               // Debugging version of system malloc()
+**     SQLITE_MEMORY_SIZE            // internal allocator #1
+**     SQLITE_MMAP_HEAP_SIZE         // internal mmap() allocator
+**     SQLITE_POW2_MEMORY_SIZE       // internal power-of-two allocator
+**
+** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
+** the default.
+*/
+#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\
+    defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\
+    defined(SQLITE_POW2_MEMORY_SIZE)>1
+# error "At most one of the following compile-time configuration options\
+ is allows: SQLITE_SYSTEM_MALLOC, SQLITE_MEMDEBUG, SQLITE_MEMORY_SIZE,\
+ SQLITE_MMAP_HEAP_SIZE, SQLITE_POW2_MEMORY_SIZE"
+#endif
+#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\
+    defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\
+    defined(SQLITE_POW2_MEMORY_SIZE)==0
+# define SQLITE_SYSTEM_MALLOC 1
+#endif
+
+/*
+** If SQLITE_MALLOC_SOFT_LIMIT is defined, then try to keep the
+** sizes of memory allocations below this value where possible.
+*/
+#if defined(SQLITE_POW2_MEMORY_SIZE) && !defined(SQLITE_MALLOC_SOFT_LIMIT)
+# define SQLITE_MALLOC_SOFT_LIMIT 1024
+#endif
+
+/*
+** We need to define _XOPEN_SOURCE as follows in order to enable
+** recursive mutexes on most unix systems.  But Mac OS X is different.
+** The _XOPEN_SOURCE define causes problems for Mac OS X we are told,
+** so it is omitted there.  See ticket #2673.
+**
+** Later we learn that _XOPEN_SOURCE is poorly or incorrectly
+** implemented on some systems.  So we avoid defining it at all
+** if it is already defined or if it is unneeded because we are
+** not doing a threadsafe build.  Ticket #2681.
+**
+** See also ticket #2741.
+*/
+#if !defined(_XOPEN_SOURCE) && !defined(__DARWIN__) && !defined(__APPLE__) && SQLITE_THREADSAFE
+#  define _XOPEN_SOURCE 500  /* Needed to enable pthread recursive mutexes */
+#endif
+
+#if defined(SQLITE_TCL) || defined(TCLSH)
+# include <tcl.h>
+#endif
+
+/*
+** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
+** Setting NDEBUG makes the code smaller and run faster.  So the following
+** lines are added to automatically set NDEBUG unless the -DSQLITE_DEBUG=1
+** option is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
+** feature.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
+# define NDEBUG 1
+#endif
+
+/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
+/************** Begin file sqlite3.h *****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the SQLite library
+** presents to client programs.  If a C-function, structure, datatype,
+** or constant definition does not appear in this file, then it is
+** not a published API of SQLite, is subject to change without
+** notice, and should not be referenced by programs that use SQLite.
+**
+** Some of the definitions that are in this file are marked as
+** "experimental".  Experimental interfaces are normally new
+** features recently added to SQLite.  We do not anticipate changes 
+** to experimental interfaces but reserve to make minor changes if
+** experience from use "in the wild" suggest such changes are prudent.
+**
+** The official C-language API documentation for SQLite is derived
+** from comments in this file.  This file is the authoritative source
+** on how SQLite interfaces are suppose to operate.
+**
+** The name of this file under configuration management is "sqlite.h.in".
+** The makefile makes some minor changes to this file (such as inserting
+** the version number) and changes its name to "sqlite3.h" as
+** part of the build process.
+**
+** @(#) $Id: sqlite.h.in,v 1.312 2008/05/12 12:39:56 drh Exp $
+*/
+#ifndef _SQLITE3_H_
+#define _SQLITE3_H_
+#include <stdarg.h>     /* Needed for the definition of va_list */
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+extern "C" {
+#endif
+
+
+/*
+** Add the ability to override 'extern'
+*/
+#ifndef SQLITE_EXTERN
+# define SQLITE_EXTERN extern
+#endif
+
+/*
+** Make sure these symbols where not defined by some previous header
+** file.
+*/
+#ifdef SQLITE_VERSION
+# undef SQLITE_VERSION
+#endif
+#ifdef SQLITE_VERSION_NUMBER
+# undef SQLITE_VERSION_NUMBER
+#endif
+
+/*
+** CAPI3REF: Compile-Time Library Version Numbers {F10010}
+**
+** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
+** the sqlite3.h file specify the version of SQLite with which
+** that header file is associated.
+**
+** The "version" of SQLite is a string of the form "X.Y.Z".
+** The phrase "alpha" or "beta" might be appended after the Z.
+** The X value is major version number always 3 in SQLite3.
+** The X value only changes when  backwards compatibility is
+** broken and we intend to never break
+** backwards compatibility.  The Y value is the minor version
+** number and only changes when
+** there are major feature enhancements that are forwards compatible
+** but not backwards compatible.  The Z value is release number
+** and is incremented with
+** each release but resets back to 0 when Y is incremented.
+**
+** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()].
+**
+** INVARIANTS:
+**
+** {F10011} The SQLITE_VERSION #define in the sqlite3.h header file
+**          evaluates to a string literal that is the SQLite version
+**          with which the header file is associated.
+**
+** {F10014} The SQLITE_VERSION_NUMBER #define resolves to an integer
+**          with the value  (X*1000000 + Y*1000 + Z) where X, Y, and
+**          Z are the major version, minor version, and release number.
+*/
+#define SQLITE_VERSION         "3.5.9"
+#define SQLITE_VERSION_NUMBER  3005009
+
+/*
+** CAPI3REF: Run-Time Library Version Numbers {F10020}
+** KEYWORDS: sqlite3_version
+**
+** These features provide the same information as the [SQLITE_VERSION]
+** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated
+** with the library instead of the header file.  Cautious programmers might
+** include a check in their application to verify that 
+** sqlite3_libversion_number() always returns the value 
+** [SQLITE_VERSION_NUMBER].
+**
+** The sqlite3_libversion() function returns the same information as is
+** in the sqlite3_version[] string constant.  The function is provided
+** for use in DLLs since DLL users usually do not have direct access to string
+** constants within the DLL.
+**
+** INVARIANTS:
+**
+** {F10021} The [sqlite3_libversion_number()] interface returns an integer
+**          equal to [SQLITE_VERSION_NUMBER]. 
+**
+** {F10022} The [sqlite3_version] string constant contains the text of the
+**          [SQLITE_VERSION] string. 
+**
+** {F10023} The [sqlite3_libversion()] function returns
+**          a pointer to the [sqlite3_version] string constant.
+*/
+SQLITE_API const char sqlite3_version[];
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API int sqlite3_libversion_number(void);
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe {F10100}
+**
+** SQLite can be compiled with or without mutexes.  When
+** the SQLITE_THREADSAFE C preprocessor macro is true, mutexes
+** are enabled and SQLite is threadsafe.  When that macro is false,
+** the mutexes are omitted.  Without the mutexes, it is not safe
+** to use SQLite from more than one thread.
+**
+** There is a measurable performance penalty for enabling mutexes.
+** So if speed is of utmost importance, it makes sense to disable
+** the mutexes.  But for maximum safety, mutexes should be enabled.
+** The default behavior is for mutexes to be enabled.
+**
+** This interface can be used by a program to make sure that the
+** version of SQLite that it is linking against was compiled with
+** the desired setting of the SQLITE_THREADSAFE macro.
+**
+** INVARIANTS:
+**
+** {F10101} The [sqlite3_threadsafe()] function returns nonzero if
+**          SQLite was compiled with its mutexes enabled or zero
+**          if SQLite was compiled with mutexes disabled.
+*/
+SQLITE_API int sqlite3_threadsafe(void);
+
+/*
+** CAPI3REF: Database Connection Handle {F12000}
+** KEYWORDS: {database connection} {database connections}
+**
+** Each open SQLite database is represented by pointer to an instance of the
+** opaque structure named "sqlite3".  It is useful to think of an sqlite3
+** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
+** [sqlite3_open_v2()] interfaces are its constructors
+** and [sqlite3_close()] is its destructor.  There are many other interfaces
+** (such as [sqlite3_prepare_v2()], [sqlite3_create_function()], and
+** [sqlite3_busy_timeout()] to name but three) that are methods on this
+** object.
+*/
+typedef struct sqlite3 sqlite3;
+
+
+/*
+** CAPI3REF: 64-Bit Integer Types {F10200}
+** KEYWORDS: sqlite_int64 sqlite_uint64
+**
+** Because there is no cross-platform way to specify 64-bit integer types
+** SQLite includes typedefs for 64-bit signed and unsigned integers.
+**
+** The sqlite3_int64 and sqlite3_uint64 are the preferred type
+** definitions.  The sqlite_int64 and sqlite_uint64 types are
+** supported for backwards compatibility only.
+**
+** INVARIANTS:
+**
+** {F10201} The [sqlite_int64] and [sqlite3_int64] types specify a
+**          64-bit signed integer.
+**
+** {F10202} The [sqlite_uint64] and [sqlite3_uint64] types specify
+**          a 64-bit unsigned integer.
+*/
+#ifdef SQLITE_INT64_TYPE
+  typedef SQLITE_INT64_TYPE sqlite_int64;
+  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
+#elif defined(_MSC_VER) || defined(__BORLANDC__)
+  typedef __int64 sqlite_int64;
+  typedef unsigned __int64 sqlite_uint64;
+#else
+  typedef long long int sqlite_int64;
+  typedef unsigned long long int sqlite_uint64;
+#endif
+typedef sqlite_int64 sqlite3_int64;
+typedef sqlite_uint64 sqlite3_uint64;
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite3_int64
+#endif
+
+/*
+** CAPI3REF: Closing A Database Connection {F12010}
+**
+** This routine is the destructor for the [sqlite3] object.  
+**
+** Applications should [sqlite3_finalize | finalize] all
+** [prepared statements] and
+** [sqlite3_blob_close | close] all [sqlite3_blob | BLOBs] 
+** associated with the [sqlite3] object prior
+** to attempting to close the [sqlite3] object.
+**
+** <todo>What happens to pending transactions?  Are they
+** rolled back, or abandoned?</todo>
+**
+** INVARIANTS:
+**
+** {F12011} The [sqlite3_close()] interface destroys an [sqlite3] object
+**          allocated by a prior call to [sqlite3_open()],
+**          [sqlite3_open16()], or [sqlite3_open_v2()].
+**
+** {F12012} The [sqlite3_close()] function releases all memory used by the
+**          connection and closes all open files.
+**
+** {F12013} If the database connection contains
+**          [prepared statements] that have not been
+**          finalized by [sqlite3_finalize()], then [sqlite3_close()]
+**          returns [SQLITE_BUSY] and leaves the connection open.
+**
+** {F12014} Giving sqlite3_close() a NULL pointer is a harmless no-op.
+**
+** LIMITATIONS:
+**
+** {U12015} The parameter to [sqlite3_close()] must be an [sqlite3] object
+**          pointer previously obtained from [sqlite3_open()] or the 
+**          equivalent, or NULL.
+**
+** {U12016} The parameter to [sqlite3_close()] must not have been previously
+**          closed.
+*/
+SQLITE_API int sqlite3_close(sqlite3 *);
+
+/*
+** The type for a callback function.
+** This is legacy and deprecated.  It is included for historical
+** compatibility and is not documented.
+*/
+typedef int (*sqlite3_callback)(void*,int,char**, char**);
+
+/*
+** CAPI3REF: One-Step Query Execution Interface {F12100}
+**
+** The sqlite3_exec() interface is a convenient way of running
+** one or more SQL statements without a lot of C code.  The
+** SQL statements are passed in as the second parameter to
+** sqlite3_exec().  The statements are evaluated one by one
+** until either an error or an interrupt is encountered or
+** until they are all done.  The 3rd parameter is an optional
+** callback that is invoked once for each row of any query results
+** produced by the SQL statements.  The 5th parameter tells where
+** to write any error messages.
+**
+** The sqlite3_exec() interface is implemented in terms of
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
+** The sqlite3_exec() routine does nothing that cannot be done
+** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
+** The sqlite3_exec() is just a convenient wrapper.
+**
+** INVARIANTS:
+** 
+** {F12101} The [sqlite3_exec()] interface evaluates zero or more UTF-8
+**          encoded, semicolon-separated, SQL statements in the
+**          zero-terminated string of its 2nd parameter within the
+**          context of the [sqlite3] object given in the 1st parameter.
+**
+** {F12104} The return value of [sqlite3_exec()] is SQLITE_OK if all
+**          SQL statements run successfully.
+**
+** {F12105} The return value of [sqlite3_exec()] is an appropriate 
+**          non-zero error code if any SQL statement fails.
+**
+** {F12107} If one or more of the SQL statements handed to [sqlite3_exec()]
+**          return results and the 3rd parameter is not NULL, then
+**          the callback function specified by the 3rd parameter is
+**          invoked once for each row of result.
+**
+** {F12110} If the callback returns a non-zero value then [sqlite3_exec()]
+**          will aborted the SQL statement it is currently evaluating,
+**          skip all subsequent SQL statements, and return [SQLITE_ABORT].
+**          <todo>What happens to *errmsg here?  Does the result code for
+**          sqlite3_errcode() get set?</todo>
+**
+** {F12113} The [sqlite3_exec()] routine will pass its 4th parameter through
+**          as the 1st parameter of the callback.
+**
+** {F12116} The [sqlite3_exec()] routine sets the 2nd parameter of its
+**          callback to be the number of columns in the current row of
+**          result.
+**
+** {F12119} The [sqlite3_exec()] routine sets the 3rd parameter of its 
+**          callback to be an array of pointers to strings holding the
+**          values for each column in the current result set row as
+**          obtained from [sqlite3_column_text()].
+**
+** {F12122} The [sqlite3_exec()] routine sets the 4th parameter of its
+**          callback to be an array of pointers to strings holding the
+**          names of result columns as obtained from [sqlite3_column_name()].
+**
+** {F12125} If the 3rd parameter to [sqlite3_exec()] is NULL then
+**          [sqlite3_exec()] never invokes a callback.  All query
+**          results are silently discarded.
+**
+** {F12128} If an error occurs while parsing or evaluating any of the SQL
+**          statements handed to [sqlite3_exec()] then [sqlite3_exec()] will
+**          return an [error code] other than [SQLITE_OK].
+**
+** {F12131} If an error occurs while parsing or evaluating any of the SQL
+**          handed to [sqlite3_exec()] and if the 5th parameter (errmsg)
+**          to [sqlite3_exec()] is not NULL, then an error message is
+**          allocated using the equivalent of [sqlite3_mprintf()] and
+**          *errmsg is made to point to that message.
+**
+** {F12134} The [sqlite3_exec()] routine does not change the value of
+**          *errmsg if errmsg is NULL or if there are no errors.
+**
+** {F12137} The [sqlite3_exec()] function sets the error code and message
+**          accessible via [sqlite3_errcode()], [sqlite3_errmsg()], and
+**          [sqlite3_errmsg16()].
+**
+** LIMITATIONS:
+**
+** {U12141} The first parameter to [sqlite3_exec()] must be an valid and open
+**          [database connection].
+**
+** {U12142} The database connection must not be closed while
+**          [sqlite3_exec()] is running.
+** 
+** {U12143} The calling function is should use [sqlite3_free()] to free
+**          the memory that *errmsg is left pointing at once the error
+**          message is no longer needed.
+**
+** {U12145} The SQL statement text in the 2nd parameter to [sqlite3_exec()]
+**          must remain unchanged while [sqlite3_exec()] is running.
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3*,                                  /* An open database */
+  const char *sql,                           /* SQL to be evaluted */
+  int (*callback)(void*,int,char**,char**),  /* Callback function */
+  void *,                                    /* 1st argument to callback */
+  char **errmsg                              /* Error msg written here */
+);
+
+/*
+** CAPI3REF: Result Codes {F10210}
+** KEYWORDS: SQLITE_OK {error code} {error codes}
+**
+** Many SQLite functions return an integer result code from the set shown
+** here in order to indicates success or failure.
+**
+** See also: [SQLITE_IOERR_READ | extended result codes]
+*/
+#define SQLITE_OK           0   /* Successful result */
+/* beginning-of-error-codes */
+#define SQLITE_ERROR        1   /* SQL error or missing database */
+#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
+#define SQLITE_PERM         3   /* Access permission denied */
+#define SQLITE_ABORT        4   /* Callback routine requested an abort */
+#define SQLITE_BUSY         5   /* The database file is locked */
+#define SQLITE_LOCKED       6   /* A table in the database is locked */
+#define SQLITE_NOMEM        7   /* A malloc() failed */
+#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
+#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
+#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
+#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
+#define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
+#define SQLITE_FULL        13   /* Insertion failed because database is full */
+#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
+#define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
+#define SQLITE_EMPTY       16   /* Database is empty */
+#define SQLITE_SCHEMA      17   /* The database schema changed */
+#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
+#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
+#define SQLITE_MISMATCH    20   /* Data type mismatch */
+#define SQLITE_MISUSE      21   /* Library used incorrectly */
+#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
+#define SQLITE_AUTH        23   /* Authorization denied */
+#define SQLITE_FORMAT      24   /* Auxiliary database format error */
+#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
+#define SQLITE_NOTADB      26   /* File opened that is not a database file */
+#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
+#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
+/* end-of-error-codes */
+
+/*
+** CAPI3REF: Extended Result Codes {F10220}
+** KEYWORDS: {extended error code} {extended error codes}
+** KEYWORDS: {extended result codes}
+**
+** In its default configuration, SQLite API routines return one of 26 integer
+** [SQLITE_OK | result codes].  However, experience has shown that
+** many of these result codes are too course-grained.  They do not provide as
+** much information about problems as programmers might like.  In an effort to
+** address this, newer versions of SQLite (version 3.3.8 and later) include
+** support for additional result codes that provide more detailed information
+** about errors. The extended result codes are enabled or disabled
+** for each database connection using the [sqlite3_extended_result_codes()]
+** API.
+** 
+** Some of the available extended result codes are listed here.
+** One may expect the number of extended result codes will be expand
+** over time.  Software that uses extended result codes should expect
+** to see new result codes in future releases of SQLite.
+**
+** The SQLITE_OK result code will never be extended.  It will always
+** be exactly zero.
+** 
+** INVARIANTS:
+**
+** {F10223} The symbolic name for an extended result code always contains
+**          a related primary result code as a prefix.
+**
+** {F10224} Primary result code names contain a single "_" character.
+**
+** {F10225} Extended result code names contain two or more "_" characters.
+**
+** {F10226} The numeric value of an extended result code contains the
+**          numeric value of its corresponding primary result code in
+**          its least significant 8 bits.
+*/
+#define SQLITE_IOERR_READ          (SQLITE_IOERR | (1<<8))
+#define SQLITE_IOERR_SHORT_READ    (SQLITE_IOERR | (2<<8))
+#define SQLITE_IOERR_WRITE         (SQLITE_IOERR | (3<<8))
+#define SQLITE_IOERR_FSYNC         (SQLITE_IOERR | (4<<8))
+#define SQLITE_IOERR_DIR_FSYNC     (SQLITE_IOERR | (5<<8))
+#define SQLITE_IOERR_TRUNCATE      (SQLITE_IOERR | (6<<8))
+#define SQLITE_IOERR_FSTAT         (SQLITE_IOERR | (7<<8))
+#define SQLITE_IOERR_UNLOCK        (SQLITE_IOERR | (8<<8))
+#define SQLITE_IOERR_RDLOCK        (SQLITE_IOERR | (9<<8))
+#define SQLITE_IOERR_DELETE        (SQLITE_IOERR | (10<<8))
+#define SQLITE_IOERR_BLOCKED       (SQLITE_IOERR | (11<<8))
+#define SQLITE_IOERR_NOMEM         (SQLITE_IOERR | (12<<8))
+
+/*
+** CAPI3REF: Flags For File Open Operations {F10230}
+**
+** These bit values are intended for use in the
+** 3rd parameter to the [sqlite3_open_v2()] interface and
+** in the 4th parameter to the xOpen method of the
+** [sqlite3_vfs] object.
+*/
+#define SQLITE_OPEN_READONLY         0x00000001
+#define SQLITE_OPEN_READWRITE        0x00000002
+#define SQLITE_OPEN_CREATE           0x00000004
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010
+#define SQLITE_OPEN_MAIN_DB          0x00000100
+#define SQLITE_OPEN_TEMP_DB          0x00000200
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000
+
+/*
+** CAPI3REF: Device Characteristics {F10240}
+**
+** The xDeviceCapabilities method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of the these
+** bit values expressing I/O characteristics of the mass storage
+** device that holds the file that the [sqlite3_io_methods]
+** refers to.
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+*/
+#define SQLITE_IOCAP_ATOMIC          0x00000001
+#define SQLITE_IOCAP_ATOMIC512       0x00000002
+#define SQLITE_IOCAP_ATOMIC1K        0x00000004
+#define SQLITE_IOCAP_ATOMIC2K        0x00000008
+#define SQLITE_IOCAP_ATOMIC4K        0x00000010
+#define SQLITE_IOCAP_ATOMIC8K        0x00000020
+#define SQLITE_IOCAP_ATOMIC16K       0x00000040
+#define SQLITE_IOCAP_ATOMIC32K       0x00000080
+#define SQLITE_IOCAP_ATOMIC64K       0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND     0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL      0x00000400
+
+/*
+** CAPI3REF: File Locking Levels {F10250}
+**
+** SQLite uses one of these integer values as the second
+** argument to calls it makes to the xLock() and xUnlock() methods
+** of an [sqlite3_io_methods] object.
+*/
+#define SQLITE_LOCK_NONE          0
+#define SQLITE_LOCK_SHARED        1
+#define SQLITE_LOCK_RESERVED      2
+#define SQLITE_LOCK_PENDING       3
+#define SQLITE_LOCK_EXCLUSIVE     4
+
+/*
+** CAPI3REF: Synchronization Type Flags {F10260}
+**
+** When SQLite invokes the xSync() method of an
+** [sqlite3_io_methods] object it uses a combination of
+** these integer values as the second argument.
+**
+** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
+** sync operation only needs to flush data to mass storage.  Inode
+** information need not be flushed. The SQLITE_SYNC_NORMAL flag means 
+** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means 
+** to use Mac OS-X style fullsync instead of fsync().
+*/
+#define SQLITE_SYNC_NORMAL        0x00002
+#define SQLITE_SYNC_FULL          0x00003
+#define SQLITE_SYNC_DATAONLY      0x00010
+
+
+/*
+** CAPI3REF: OS Interface Open File Handle {F11110}
+**
+** An [sqlite3_file] object represents an open file in the OS
+** interface layer.  Individual OS interface implementations will
+** want to subclass this object by appending additional fields
+** for their own use.  The pMethods entry is a pointer to an
+** [sqlite3_io_methods] object that defines methods for performing
+** I/O operations on the open file.
+*/
+typedef struct sqlite3_file sqlite3_file;
+struct sqlite3_file {
+  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
+};
+
+/*
+** CAPI3REF: OS Interface File Virtual Methods Object {F11120}
+**
+** Every file opened by the [sqlite3_vfs] xOpen method contains a pointer to
+** an instance of this object.  This object defines the
+** methods used to perform various operations against the open file.
+**
+** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
+** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
+*  The second choice is an
+** OS-X style fullsync.  The SQLITE_SYNC_DATA flag may be ORed in to
+** indicate that only the data of the file and not its inode needs to be
+** synced.
+** 
+** The integer values to xLock() and xUnlock() are one of
+** <ul>
+** <li> [SQLITE_LOCK_NONE],
+** <li> [SQLITE_LOCK_SHARED],
+** <li> [SQLITE_LOCK_RESERVED],
+** <li> [SQLITE_LOCK_PENDING], or
+** <li> [SQLITE_LOCK_EXCLUSIVE].
+** </ul>
+** xLock() increases the lock. xUnlock() decreases the lock.  
+** The xCheckReservedLock() method looks
+** to see if any database connection, either in this
+** process or in some other process, is holding an RESERVED,
+** PENDING, or EXCLUSIVE lock on the file.  It returns true
+** if such a lock exists and false if not.
+** 
+** The xFileControl() method is a generic interface that allows custom
+** VFS implementations to directly control an open file using the
+** [sqlite3_file_control()] interface.  The second "op" argument
+** is an integer opcode.   The third
+** argument is a generic pointer which is intended to be a pointer
+** to a structure that may contain arguments or space in which to
+** write return values.  Potential uses for xFileControl() might be
+** functions to enable blocking locks with timeouts, to change the
+** locking strategy (for example to use dot-file locks), to inquire
+** about the status of a lock, or to break stale locks.  The SQLite
+** core reserves opcodes less than 100 for its own use. 
+** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
+** Applications that define a custom xFileControl method should use opcodes 
+** greater than 100 to avoid conflicts.
+**
+** The xSectorSize() method returns the sector size of the
+** device that underlies the file.  The sector size is the
+** minimum write that can be performed without disturbing
+** other bytes in the file.  The xDeviceCharacteristics()
+** method returns a bit vector describing behaviors of the
+** underlying device:
+**
+** <ul>
+** <li> [SQLITE_IOCAP_ATOMIC]
+** <li> [SQLITE_IOCAP_ATOMIC512]
+** <li> [SQLITE_IOCAP_ATOMIC1K]
+** <li> [SQLITE_IOCAP_ATOMIC2K]
+** <li> [SQLITE_IOCAP_ATOMIC4K]
+** <li> [SQLITE_IOCAP_ATOMIC8K]
+** <li> [SQLITE_IOCAP_ATOMIC16K]
+** <li> [SQLITE_IOCAP_ATOMIC32K]
+** <li> [SQLITE_IOCAP_ATOMIC64K]
+** <li> [SQLITE_IOCAP_SAFE_APPEND]
+** <li> [SQLITE_IOCAP_SEQUENTIAL]
+** </ul>
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+*/
+typedef struct sqlite3_io_methods sqlite3_io_methods;
+struct sqlite3_io_methods {
+  int iVersion;
+  int (*xClose)(sqlite3_file*);
+  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
+  int (*xSync)(sqlite3_file*, int flags);
+  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
+  int (*xLock)(sqlite3_file*, int);
+  int (*xUnlock)(sqlite3_file*, int);
+  int (*xCheckReservedLock)(sqlite3_file*);
+  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
+  int (*xSectorSize)(sqlite3_file*);
+  int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Additional methods may be added in future releases */
+};
+
+/*
+** CAPI3REF: Standard File Control Opcodes {F11310}
+**
+** These integer constants are opcodes for the xFileControl method
+** of the [sqlite3_io_methods] object and to the [sqlite3_file_control()]
+** interface.
+**
+** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to write the current state of
+** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
+** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
+** into an integer that the pArg argument points to. This capability
+** is used during testing and only needs to be supported when SQLITE_TEST
+** is defined.
+*/
+#define SQLITE_FCNTL_LOCKSTATE        1
+
+/*
+** CAPI3REF: Mutex Handle {F17110}
+**
+** The mutex module within SQLite defines [sqlite3_mutex] to be an
+** abstract type for a mutex object.  The SQLite core never looks
+** at the internal representation of an [sqlite3_mutex].  It only
+** deals with pointers to the [sqlite3_mutex] object.
+**
+** Mutexes are created using [sqlite3_mutex_alloc()].
+*/
+typedef struct sqlite3_mutex sqlite3_mutex;
+
+/*
+** CAPI3REF: OS Interface Object {F11140}
+**
+** An instance of this object defines the interface between the
+** SQLite core and the underlying operating system.  The "vfs"
+** in the name of the object stands for "virtual file system".
+**
+** The iVersion field is initially 1 but may be larger for future
+** versions of SQLite.  Additional fields may be appended to this
+** object when the iVersion value is increased.
+**
+** The szOsFile field is the size of the subclassed [sqlite3_file]
+** structure used by this VFS.  mxPathname is the maximum length of
+** a pathname in this VFS.
+**
+** Registered sqlite3_vfs objects are kept on a linked list formed by
+** the pNext pointer.  The [sqlite3_vfs_register()]
+** and [sqlite3_vfs_unregister()] interfaces manage this list
+** in a thread-safe way.  The [sqlite3_vfs_find()] interface
+** searches the list.
+**
+** The pNext field is the only field in the sqlite3_vfs 
+** structure that SQLite will ever modify.  SQLite will only access
+** or modify this field while holding a particular static mutex.
+** The application should never modify anything within the sqlite3_vfs
+** object once the object has been registered.
+**
+** The zName field holds the name of the VFS module.  The name must
+** be unique across all VFS modules.
+**
+** {F11141} SQLite will guarantee that the zFilename string passed to
+** xOpen() is a full pathname as generated by xFullPathname() and
+** that the string will be valid and unchanged until xClose() is
+** called.  {END} So the [sqlite3_file] can store a pointer to the
+** filename if it needs to remember the filename for some reason.
+**
+** {F11142} The flags argument to xOpen() includes all bits set in
+** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
+** or [sqlite3_open16()] is used, then flags includes at least
+** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. {END}
+** If xOpen() opens a file read-only then it sets *pOutFlags to
+** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be
+** set.
+** 
+** {F11143} SQLite will also add one of the following flags to the xOpen()
+** call, depending on the object being opened:
+** 
+** <ul>
+** <li>  [SQLITE_OPEN_MAIN_DB]
+** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
+** <li>  [SQLITE_OPEN_TEMP_DB]
+** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
+** <li>  [SQLITE_OPEN_TRANSIENT_DB]
+** <li>  [SQLITE_OPEN_SUBJOURNAL]
+** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
+** </ul> {END}
+**
+** The file I/O implementation can use the object type flags to
+** changes the way it deals with files.  For example, an application
+** that does not care about crash recovery or rollback might make
+** the open of a journal file a no-op.  Writes to this journal would
+** also be no-ops, and any attempt to read the journal would return 
+** SQLITE_IOERR.  Or the implementation might recognize that a database 
+** file will be doing page-aligned sector reads and writes in a random 
+** order and set up its I/O subsystem accordingly.
+** 
+** SQLite might also add one of the following flags to the xOpen
+** method:
+** 
+** <ul>
+** <li> [SQLITE_OPEN_DELETEONCLOSE]
+** <li> [SQLITE_OPEN_EXCLUSIVE]
+** </ul>
+** 
+** {F11145} The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
+** deleted when it is closed.  {F11146} The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP  databases, journals and for subjournals. 
+** {F11147} The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened
+** for exclusive access.  This flag is set for all files except
+** for the main database file. {END}
+** 
+** {F11148} At least szOsFile bytes of memory are allocated by SQLite 
+** to hold the  [sqlite3_file] structure passed as the third 
+** argument to xOpen.  {END}  The xOpen method does not have to
+** allocate the structure; it should just fill it in.
+** 
+** {F11149} The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 
+** to test for the existance of a file,
+** or [SQLITE_ACCESS_READWRITE] to test to see
+** if a file is readable and writable, or [SQLITE_ACCESS_READ]
+** to test to see if a file is at least readable.  {END} The file can be a 
+** directory.
+** 
+** {F11150} SQLite will always allocate at least mxPathname+1 bytes for
+** the output buffers for xGetTempname and xFullPathname. {F11151} The exact
+** size of the output buffer is also passed as a parameter to both 
+** methods. {END} If the output buffer is not large enough, SQLITE_CANTOPEN
+** should be returned. As this is handled as a fatal error by SQLite,
+** vfs implementations should endeavor to prevent this by setting 
+** mxPathname to a sufficiently large value.
+** 
+** The xRandomness(), xSleep(), and xCurrentTime() interfaces
+** are not strictly a part of the filesystem, but they are
+** included in the VFS structure for completeness.
+** The xRandomness() function attempts to return nBytes bytes
+** of good-quality randomness into zOut.  The return value is
+** the actual number of bytes of randomness obtained.  The
+** xSleep() method causes the calling thread to sleep for at
+** least the number of microseconds given.  The xCurrentTime()
+** method returns a Julian Day Number for the current date and
+** time.
+*/
+typedef struct sqlite3_vfs sqlite3_vfs;
+struct sqlite3_vfs {
+  int iVersion;            /* Structure version number */
+  int szOsFile;            /* Size of subclassed sqlite3_file */
+  int mxPathname;          /* Maximum file pathname length */
+  sqlite3_vfs *pNext;      /* Next registered VFS */
+  const char *zName;       /* Name of this virtual file system */
+  void *pAppData;          /* Pointer to application-specific data */
+  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
+               int flags, int *pOutFlags);
+  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
+  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags);
+  int (*xGetTempname)(sqlite3_vfs*, int nOut, char *zOut);
+  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
+  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
+  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
+  void *(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol);
+  void (*xDlClose)(sqlite3_vfs*, void*);
+  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
+  int (*xSleep)(sqlite3_vfs*, int microseconds);
+  int (*xCurrentTime)(sqlite3_vfs*, double*);
+  /* New fields may be appended in figure versions.  The iVersion
+  ** value will increment whenever this happens. */
+};
+
+/*
+** CAPI3REF: Flags for the xAccess VFS method {F11190}
+**
+** {F11191} These integer constants can be used as the third parameter to
+** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
+** what kind of permissions the xAccess method is
+** looking for.  {F11192} With SQLITE_ACCESS_EXISTS, the xAccess method
+** simply checks to see if the file exists. {F11193} With
+** SQLITE_ACCESS_READWRITE, the xAccess method checks to see
+** if the file is both readable and writable.  {F11194} With
+** SQLITE_ACCESS_READ the xAccess method
+** checks to see if the file is readable.
+*/
+#define SQLITE_ACCESS_EXISTS    0
+#define SQLITE_ACCESS_READWRITE 1
+#define SQLITE_ACCESS_READ      2
+
+/*
+** CAPI3REF: Enable Or Disable Extended Result Codes {F12200}
+**
+** The sqlite3_extended_result_codes() routine enables or disables the
+** [SQLITE_IOERR_READ | extended result codes] feature of SQLite.
+** The extended result codes are disabled by default for historical
+** compatibility.
+**
+** INVARIANTS:
+**
+** {F12201} Each new [database connection] has the 
+**          [extended result codes] feature
+**          disabled by default.
+**
+** {F12202} The [sqlite3_extended_result_codes(D,F)] interface will enable
+**          [extended result codes] for the 
+**          [database connection] D if the F parameter
+**          is true, or disable them if F is false.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
+
+/*
+** CAPI3REF: Last Insert Rowid {F12220}
+**
+** Each entry in an SQLite table has a unique 64-bit signed
+** integer key called the "rowid". The rowid is always available
+** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
+** names are not also used by explicitly declared columns. If
+** the table has a column of type INTEGER PRIMARY KEY then that column
+** is another alias for the rowid.
+**
+** This routine returns the rowid of the most recent
+** successful INSERT into the database from the database connection
+** shown in the first argument.  If no successful inserts
+** have ever occurred on this database connection, zero is returned.
+**
+** If an INSERT occurs within a trigger, then the rowid of the
+** inserted row is returned by this routine as long as the trigger
+** is running.  But once the trigger terminates, the value returned
+** by this routine reverts to the last value inserted before the
+** trigger fired.
+**
+** An INSERT that fails due to a constraint violation is not a
+** successful insert and does not change the value returned by this
+** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** and INSERT OR ABORT make no changes to the return value of this
+** routine when their insertion fails.  When INSERT OR REPLACE 
+** encounters a constraint violation, it does not fail.  The
+** INSERT continues to completion after deleting rows that caused
+** the constraint problem so INSERT OR REPLACE will always change
+** the return value of this interface. 
+**
+** For the purposes of this routine, an insert is considered to
+** be successful even if it is subsequently rolled back.
+**
+** INVARIANTS:
+**
+** {F12221} The [sqlite3_last_insert_rowid()] function returns the
+**          rowid of the most recent successful insert done
+**          on the same database connection and within the same
+**          trigger context, or zero if there have
+**          been no qualifying inserts on that connection.
+**
+** {F12223} The [sqlite3_last_insert_rowid()] function returns
+**          same value when called from the same trigger context
+**          immediately before and after a ROLLBACK.
+**
+** LIMITATIONS:
+**
+** {U12232} If a separate thread does a new insert on the same
+**          database connection while the [sqlite3_last_insert_rowid()]
+**          function is running and thus changes the last insert rowid,
+**          then the value returned by [sqlite3_last_insert_rowid()] is
+**          unpredictable and might not equal either the old or the new
+**          last insert rowid.
+*/
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+
+/*
+** CAPI3REF: Count The Number Of Rows Modified {F12240}
+**
+** This function returns the number of database rows that were changed
+** or inserted or deleted by the most recently completed SQL statement
+** on the connection specified by the first parameter.  Only
+** changes that are directly specified by the INSERT, UPDATE, or
+** DELETE statement are counted.  Auxiliary changes caused by
+** triggers are not counted. Use the [sqlite3_total_changes()] function
+** to find the total number of changes including changes caused by triggers.
+**
+** A "row change" is a change to a single row of a single table
+** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
+** are changed as side effects of REPLACE constraint resolution,
+** rollback, ABORT processing, DROP TABLE, or by any other
+** mechanisms do not count as direct row changes.
+**
+** A "trigger context" is a scope of execution that begins and
+** ends with the script of a trigger.  Most SQL statements are
+** evaluated outside of any trigger.  This is the "top level"
+** trigger context.  If a trigger fires from the top level, a
+** new trigger context is entered for the duration of that one
+** trigger.  Subtriggers create subcontexts for their duration.
+**
+** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
+** not create a new trigger context.
+**
+** This function returns the number of direct row changes in the
+** most recent INSERT, UPDATE, or DELETE statement within the same
+** trigger context.
+**
+** So when called from the top level, this function returns the
+** number of changes in the most recent INSERT, UPDATE, or DELETE
+** that also occurred at the top level.
+** Within the body of a trigger, the sqlite3_changes() interface
+** can be called to find the number of
+** changes in the most recently completed INSERT, UPDATE, or DELETE
+** statement within the body of the same trigger.
+** However, the number returned does not include in changes
+** caused by subtriggers since they have their own context.
+**
+** SQLite implements the command "DELETE FROM table" without
+** a WHERE clause by dropping and recreating the table.  (This is much
+** faster than going through and deleting individual elements from the
+** table.)  Because of this optimization, the deletions in
+** "DELETE FROM table" are not row changes and will not be counted
+** by the sqlite3_changes() or [sqlite3_total_changes()] functions.
+** To get an accurate count of the number of rows deleted, use
+** "DELETE FROM table WHERE 1" instead.
+**
+** INVARIANTS:
+**
+** {F12241} The [sqlite3_changes()] function returns the number of
+**          row changes caused by the most recent INSERT, UPDATE,
+**          or DELETE statement on the same database connection and
+**          within the same trigger context, or zero if there have
+**          not been any qualifying row changes.
+**
+** LIMITATIONS:
+**
+** {U12252} If a separate thread makes changes on the same database connection
+**          while [sqlite3_changes()] is running then the value returned
+**          is unpredictable and unmeaningful.
+*/
+SQLITE_API int sqlite3_changes(sqlite3*);
+
+/*
+** CAPI3REF: Total Number Of Rows Modified {F12260}
+***
+** This function returns the number of row changes caused
+** by INSERT, UPDATE or DELETE statements since the database handle
+** was opened.  The count includes all changes from all trigger
+** contexts.  But the count does not include changes used to
+** implement REPLACE constraints, do rollbacks or ABORT processing,
+** or DROP table processing.
+** The changes
+** are counted as soon as the statement that makes them is completed 
+** (when the statement handle is passed to [sqlite3_reset()] or 
+** [sqlite3_finalize()]).
+**
+** SQLite implements the command "DELETE FROM table" without
+** a WHERE clause by dropping and recreating the table.  (This is much
+** faster than going
+** through and deleting individual elements from the table.)  Because of
+** this optimization, the change count for "DELETE FROM table" will be
+** zero regardless of the number of elements that were originally in the
+** table. To get an accurate count of the number of rows deleted, use
+** "DELETE FROM table WHERE 1" instead.
+**
+** See also the [sqlite3_changes()] interface.
+**
+** INVARIANTS:
+** 
+** {F12261} The [sqlite3_total_changes()] returns the total number
+**          of row changes caused by INSERT, UPDATE, and/or DELETE
+**          statements on the same [database connection], in any
+**          trigger context, since the database connection was
+**          created.
+**
+** LIMITATIONS:
+**
+** {U12264} If a separate thread makes changes on the same database connection
+**          while [sqlite3_total_changes()] is running then the value 
+**          returned is unpredictable and unmeaningful.
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3*);
+
+/*
+** CAPI3REF: Interrupt A Long-Running Query {F12270}
+**
+** This function causes any pending database operation to abort and
+** return at its earliest opportunity. This routine is typically
+** called in response to a user action such as pressing "Cancel"
+** or Ctrl-C where the user wants a long query operation to halt
+** immediately.
+**
+** It is safe to call this routine from a thread different from the
+** thread that is currently running the database operation.  But it
+** is not safe to call this routine with a database connection that
+** is closed or might close before sqlite3_interrupt() returns.
+**
+** If an SQL is very nearly finished at the time when sqlite3_interrupt()
+** is called, then it might not have an opportunity to be interrupted.
+** It might continue to completion.
+** An SQL operation that is interrupted will return
+** [SQLITE_INTERRUPT].  If the interrupted SQL operation is an
+** INSERT, UPDATE, or DELETE that is inside an explicit transaction, 
+** then the entire transaction will be rolled back automatically.
+** A call to sqlite3_interrupt() has no effect on SQL statements
+** that are started after sqlite3_interrupt() returns.
+**
+** INVARIANTS:
+**
+** {F12271} The [sqlite3_interrupt()] interface will force all running
+**          SQL statements associated with the same database connection
+**          to halt after processing at most one additional row of
+**          data.
+**
+** {F12272} Any SQL statement that is interrupted by [sqlite3_interrupt()]
+**          will return [SQLITE_INTERRUPT].
+**
+** LIMITATIONS:
+**
+** {U12279} If the database connection closes while [sqlite3_interrupt()]
+**          is running then bad things will likely happen.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3*);
+
+/*
+** CAPI3REF: Determine If An SQL Statement Is Complete {F10510}
+**
+** These routines are useful for command-line input to determine if the
+** currently entered text seems to form complete a SQL statement or
+** if additional input is needed before sending the text into
+** SQLite for parsing.  These routines return true if the input string
+** appears to be a complete SQL statement.  A statement is judged to be
+** complete if it ends with a semicolon token and is not a fragment of a
+** CREATE TRIGGER statement.  Semicolons that are embedded within
+** string literals or quoted identifier names or comments are not
+** independent tokens (they are part of the token in which they are
+** embedded) and thus do not count as a statement terminator.
+**
+** These routines do not parse the SQL and
+** so will not detect syntactically incorrect SQL.
+**
+** INVARIANTS:
+**
+** {F10511} The sqlite3_complete() and sqlite3_complete16() functions
+**          return true (non-zero) if and only if the last
+**          non-whitespace token in their input is a semicolon that
+**          is not in between the BEGIN and END of a CREATE TRIGGER
+**          statement.
+**
+** LIMITATIONS:
+**
+** {U10512} The input to sqlite3_complete() must be a zero-terminated
+**          UTF-8 string.
+**
+** {U10513} The input to sqlite3_complete16() must be a zero-terminated
+**          UTF-16 string in native byte order.
+*/
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
+
+/*
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {F12310}
+**
+** This routine identifies a callback function that might be
+** invoked whenever an attempt is made to open a database table 
+** that another thread or process has locked.
+** If the busy callback is NULL, then [SQLITE_BUSY]
+** or [SQLITE_IOERR_BLOCKED]
+** is returned immediately upon encountering the lock.
+** If the busy callback is not NULL, then the
+** callback will be invoked with two arguments.  The
+** first argument to the handler is a copy of the void* pointer which
+** is the third argument to this routine.  The second argument to
+** the handler is the number of times that the busy handler has
+** been invoked for this locking event.   If the
+** busy callback returns 0, then no additional attempts are made to
+** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
+** If the callback returns non-zero, then another attempt
+** is made to open the database for reading and the cycle repeats.
+**
+** The presence of a busy handler does not guarantee that
+** it will be invoked when there is lock contention.
+** If SQLite determines that invoking the busy handler could result in
+** a deadlock, it will go ahead and return [SQLITE_BUSY] or
+** [SQLITE_IOERR_BLOCKED] instead of invoking the
+** busy handler.
+** Consider a scenario where one process is holding a read lock that
+** it is trying to promote to a reserved lock and
+** a second process is holding a reserved lock that it is trying
+** to promote to an exclusive lock.  The first process cannot proceed
+** because it is blocked by the second and the second process cannot
+** proceed because it is blocked by the first.  If both processes
+** invoke the busy handlers, neither will make any progress.  Therefore,
+** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
+** will induce the first process to release its read lock and allow
+** the second process to proceed.
+**
+** The default busy callback is NULL.
+**
+** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
+** when SQLite is in the middle of a large transaction where all the
+** changes will not fit into the in-memory cache.  SQLite will
+** already hold a RESERVED lock on the database file, but it needs
+** to promote this lock to EXCLUSIVE so that it can spill cache
+** pages into the database file without harm to concurrent
+** readers.  If it is unable to promote the lock, then the in-memory
+** cache will be left in an inconsistent state and so the error
+** code is promoted from the relatively benign [SQLITE_BUSY] to
+** the more severe [SQLITE_IOERR_BLOCKED].  This error code promotion
+** forces an automatic rollback of the changes.  See the
+** <a href="http://www.sqlite.org/cvstrac/wiki?p=CorruptionFollowingBusyError">
+** CorruptionFollowingBusyError</a> wiki page for a discussion of why
+** this is important.
+**	
+** There can only be a single busy handler defined for each database
+** connection.  Setting a new busy handler clears any previous one. 
+** Note that calling [sqlite3_busy_timeout()] will also set or clear
+** the busy handler.
+**
+** INVARIANTS:
+**
+** {F12311} The [sqlite3_busy_handler()] function replaces the busy handler
+**          callback in the database connection identified by the 1st
+**          parameter with a new busy handler identified by the 2nd and 3rd
+**          parameters.
+**
+** {F12312} The default busy handler for new database connections is NULL.
+**
+** {F12314} When two or more database connection share a common cache,
+**          the busy handler for the database connection currently using
+**          the cache is invoked when the cache encounters a lock.
+**
+** {F12316} If a busy handler callback returns zero, then the SQLite
+**          interface that provoked the locking event will return
+**          [SQLITE_BUSY].
+**
+** {F12318} SQLite will invokes the busy handler with two argument which
+**          are a copy of the pointer supplied by the 3rd parameter to
+**          [sqlite3_busy_handler()] and a count of the number of prior
+**          invocations of the busy handler for the same locking event.
+**
+** LIMITATIONS:
+**
+** {U12319} A busy handler should not call close the database connection
+**          or prepared statement that invoked the busy handler.
+*/
+SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
+
+/*
+** CAPI3REF: Set A Busy Timeout {F12340}
+**
+** This routine sets a [sqlite3_busy_handler | busy handler]
+** that sleeps for a while when a
+** table is locked.  The handler will sleep multiple times until 
+** at least "ms" milliseconds of sleeping have been done. {F12343} After
+** "ms" milliseconds of sleeping, the handler returns 0 which
+** causes [sqlite3_step()] to return [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
+**
+** Calling this routine with an argument less than or equal to zero
+** turns off all busy handlers.
+**
+** There can only be a single busy handler for a particular database
+** connection.  If another busy handler was defined  
+** (using [sqlite3_busy_handler()]) prior to calling
+** this routine, that other busy handler is cleared.
+**
+** INVARIANTS:
+**
+** {F12341} The [sqlite3_busy_timeout()] function overrides any prior
+**          [sqlite3_busy_timeout()] or [sqlite3_busy_handler()] setting
+**          on the same database connection.
+**
+** {F12343} If the 2nd parameter to [sqlite3_busy_timeout()] is less than
+**          or equal to zero, then the busy handler is cleared so that
+**          all subsequent locking events immediately return [SQLITE_BUSY].
+**
+** {F12344} If the 2nd parameter to [sqlite3_busy_timeout()] is a positive
+**          number N, then a busy handler is set that repeatedly calls
+**          the xSleep() method in the VFS interface until either the
+**          lock clears or until the cumulative sleep time reported back
+**          by xSleep() exceeds N milliseconds.
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
+
+/*
+** CAPI3REF: Convenience Routines For Running Queries {F12370}
+**
+** Definition: A <b>result table</b> is memory data structure created by the
+** [sqlite3_get_table()] interface.  A result table records the
+** complete query results from one or more queries.
+**
+** The table conceptually has a number of rows and columns.  But
+** these numbers are not part of the result table itself.  These
+** numbers are obtained separately.  Let N be the number of rows
+** and M be the number of columns.
+**
+** A result table is an array of pointers to zero-terminated
+** UTF-8 strings.  There are (N+1)*M elements in the array.  
+** The first M pointers point to zero-terminated strings that 
+** contain the names of the columns.
+** The remaining entries all point to query results.  NULL
+** values are give a NULL pointer.  All other values are in
+** their UTF-8 zero-terminated string representation as returned by
+** [sqlite3_column_text()].
+**
+** A result table might consists of one or more memory allocations.
+** It is not safe to pass a result table directly to [sqlite3_free()].
+** A result table should be deallocated using [sqlite3_free_table()].
+**
+** As an example of the result table format, suppose a query result
+** is as follows:
+**
+** <blockquote><pre>
+**        Name        | Age
+**        -----------------------
+**        Alice       | 43
+**        Bob         | 28
+**        Cindy       | 21
+** </pre></blockquote>
+**
+** There are two column (M==2) and three rows (N==3).  Thus the
+** result table has 8 entries.  Suppose the result table is stored
+** in an array names azResult.  Then azResult holds this content:
+**
+** <blockquote><pre>
+**        azResult&#91;0] = "Name";
+**        azResult&#91;1] = "Age";
+**        azResult&#91;2] = "Alice";
+**        azResult&#91;3] = "43";
+**        azResult&#91;4] = "Bob";
+**        azResult&#91;5] = "28";
+**        azResult&#91;6] = "Cindy";
+**        azResult&#91;7] = "21";
+** </pre></blockquote>
+**
+** The sqlite3_get_table() function evaluates one or more
+** semicolon-separated SQL statements in the zero-terminated UTF-8
+** string of its 2nd parameter.  It returns a result table to the
+** pointer given in its 3rd parameter.
+**
+** After the calling function has finished using the result, it should 
+** pass the pointer to the result table to sqlite3_free_table() in order to 
+** release the memory that was malloc-ed.  Because of the way the 
+** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
+** function must not try to call [sqlite3_free()] directly.  Only 
+** [sqlite3_free_table()] is able to release the memory properly and safely.
+**
+** The sqlite3_get_table() interface is implemented as a wrapper around
+** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
+** to any internal data structures of SQLite.  It uses only the public
+** interface defined here.  As a consequence, errors that occur in the
+** wrapper layer outside of the internal [sqlite3_exec()] call are not
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
+**
+** INVARIANTS:
+**
+** {F12371} If a [sqlite3_get_table()] fails a memory allocation, then
+**          it frees the result table under construction, aborts the
+**          query in process, skips any subsequent queries, sets the
+**          *resultp output pointer to NULL and returns [SQLITE_NOMEM].
+**
+** {F12373} If the ncolumn parameter to [sqlite3_get_table()] is not NULL
+**          then [sqlite3_get_table()] write the number of columns in the
+**          result set of the query into *ncolumn if the query is
+**          successful (if the function returns SQLITE_OK).
+**
+** {F12374} If the nrow parameter to [sqlite3_get_table()] is not NULL
+**          then [sqlite3_get_table()] write the number of rows in the
+**          result set of the query into *nrow if the query is
+**          successful (if the function returns SQLITE_OK).
+**
+** {F12376} The [sqlite3_get_table()] function sets its *ncolumn value
+**          to the number of columns in the result set of the query in the
+**          sql parameter, or to zero if the query in sql has an empty
+**          result set.
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3*,             /* An open database */
+  const char *sql,      /* SQL to be evaluated */
+  char ***pResult,      /* Results of the query */
+  int *nrow,            /* Number of result rows written here */
+  int *ncolumn,         /* Number of result columns written here */
+  char **errmsg         /* Error msg written here */
+);
+SQLITE_API void sqlite3_free_table(char **result);
+
+/*
+** CAPI3REF: Formatted String Printing Functions {F17400}
+**
+** These routines are workalikes of the "printf()" family of functions
+** from the standard C library.
+**
+** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** results into memory obtained from [sqlite3_malloc()].
+** The strings returned by these two routines should be
+** released by [sqlite3_free()].   Both routines return a
+** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
+** memory to hold the resulting string.
+**
+** In sqlite3_snprintf() routine is similar to "snprintf()" from
+** the standard C library.  The result is written into the
+** buffer supplied as the second parameter whose size is given by
+** the first parameter. Note that the order of the
+** first two parameters is reversed from snprintf().  This is an
+** historical accident that cannot be fixed without breaking
+** backwards compatibility.  Note also that sqlite3_snprintf()
+** returns a pointer to its buffer instead of the number of
+** characters actually written into the buffer.  We admit that
+** the number of characters written would be a more useful return
+** value but we cannot change the implementation of sqlite3_snprintf()
+** now without breaking compatibility.
+**
+** As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  The first
+** parameter "n" is the total size of the buffer, including space for
+** the zero terminator.  So the longest string that can be completely
+** written will be n-1 characters.
+**
+** These routines all implement some additional formatting
+** options that are useful for constructing SQL statements.
+** All of the usual printf formatting options apply.  In addition, there
+** is are "%q", "%Q", and "%z" options.
+**
+** The %q option works like %s in that it substitutes a null-terminated
+** string from the argument list.  But %q also doubles every '\'' character.
+** %q is designed for use inside a string literal.  By doubling each '\''
+** character it escapes that character and allows it to be inserted into
+** the string.
+**
+** For example, so some string variable contains text as follows:
+**
+** <blockquote><pre>
+**  char *zText = "It's a happy day!";
+** </pre></blockquote>
+**
+** One can use this text in an SQL statement as follows:
+**
+** <blockquote><pre>
+**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
+**  sqlite3_exec(db, zSQL, 0, 0, 0);
+**  sqlite3_free(zSQL);
+** </pre></blockquote>
+**
+** Because the %q format string is used, the '\'' character in zText
+** is escaped and the SQL generated is as follows:
+**
+** <blockquote><pre>
+**  INSERT INTO table1 VALUES('It''s a happy day!')
+** </pre></blockquote>
+**
+** This is correct.  Had we used %s instead of %q, the generated SQL
+** would have looked like this:
+**
+** <blockquote><pre>
+**  INSERT INTO table1 VALUES('It's a happy day!');
+** </pre></blockquote>
+**
+** This second example is an SQL syntax error.  As a general rule you
+** should always use %q instead of %s when inserting text into a string 
+** literal.
+**
+** The %Q option works like %q except it also adds single quotes around
+** the outside of the total string.  Or if the parameter in the argument
+** list is a NULL pointer, %Q substitutes the text "NULL" (without single
+** quotes) in place of the %Q option. {END}  So, for example, one could say:
+**
+** <blockquote><pre>
+**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
+**  sqlite3_exec(db, zSQL, 0, 0, 0);
+**  sqlite3_free(zSQL);
+** </pre></blockquote>
+**
+** The code above will render a correct SQL statement in the zSQL
+** variable even if the zText variable is a NULL pointer.
+**
+** The "%z" formatting option works exactly like "%s" with the
+** addition that after the string has been read and copied into
+** the result, [sqlite3_free()] is called on the input string. {END}
+**
+** INVARIANTS:
+**
+** {F17403}  The [sqlite3_mprintf()] and [sqlite3_vmprintf()] interfaces
+**           return either pointers to zero-terminated UTF-8 strings held in
+**           memory obtained from [sqlite3_malloc()] or NULL pointers if
+**           a call to [sqlite3_malloc()] fails.
+**
+** {F17406}  The [sqlite3_snprintf()] interface writes a zero-terminated
+**           UTF-8 string into the buffer pointed to by the second parameter
+**           provided that the first parameter is greater than zero.
+**
+** {F17407}  The [sqlite3_snprintf()] interface does not writes slots of
+**           its output buffer (the second parameter) outside the range
+**           of 0 through N-1 (where N is the first parameter)
+**           regardless of the length of the string
+**           requested by the format specification.
+**   
+*/
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+
+/*
+** CAPI3REF: Memory Allocation Subsystem {F17300}
+**
+** The SQLite core  uses these three routines for all of its own
+** internal memory allocation needs. "Core" in the previous sentence
+** does not include operating-system specific VFS implementation.  The
+** windows VFS uses native malloc and free for some operations.
+**
+** The sqlite3_malloc() routine returns a pointer to a block
+** of memory at least N bytes in length, where N is the parameter.
+** If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  If the parameter N to
+** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
+** a NULL pointer.
+**
+** Calling sqlite3_free() with a pointer previously returned
+** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
+** that it might be reused.  The sqlite3_free() routine is
+** a no-op if is called with a NULL pointer.  Passing a NULL pointer
+** to sqlite3_free() is harmless.  After being freed, memory
+** should neither be read nor written.  Even reading previously freed
+** memory might result in a segmentation fault or other severe error.
+** Memory corruption, a segmentation fault, or other severe error
+** might result if sqlite3_free() is called with a non-NULL pointer that
+** was not obtained from sqlite3_malloc() or sqlite3_free().
+**
+** The sqlite3_realloc() interface attempts to resize a
+** prior memory allocation to be at least N bytes, where N is the
+** second parameter.  The memory allocation to be resized is the first
+** parameter.  If the first parameter to sqlite3_realloc()
+** is a NULL pointer then its behavior is identical to calling
+** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
+** If the second parameter to sqlite3_realloc() is zero or
+** negative then the behavior is exactly the same as calling
+** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
+** Sqlite3_realloc() returns a pointer to a memory allocation
+** of at least N bytes in size or NULL if sufficient memory is unavailable.
+** If M is the size of the prior allocation, then min(N,M) bytes
+** of the prior allocation are copied into the beginning of buffer returned
+** by sqlite3_realloc() and the prior allocation is freed.
+** If sqlite3_realloc() returns NULL, then the prior allocation
+** is not freed.
+**
+** The memory returned by sqlite3_malloc() and sqlite3_realloc()
+** is always aligned to at least an 8 byte boundary. {END}
+**
+** The default implementation
+** of the memory allocation subsystem uses the malloc(), realloc()
+** and free() provided by the standard C library. {F17382} However, if 
+** SQLite is compiled with the following C preprocessor macro
+**
+** <blockquote> SQLITE_MEMORY_SIZE=<i>NNN</i> </blockquote>
+**
+** where <i>NNN</i> is an integer, then SQLite create a static
+** array of at least <i>NNN</i> bytes in size and use that array
+** for all of its dynamic memory allocation needs. {END}  Additional
+** memory allocator options may be added in future releases.
+**
+** In SQLite version 3.5.0 and 3.5.1, it was possible to define
+** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
+** implementation of these routines to be omitted.  That capability
+** is no longer provided.  Only built-in memory allocators can be
+** used.
+**
+** The windows OS interface layer calls
+** the system malloc() and free() directly when converting
+** filenames between the UTF-8 encoding used by SQLite
+** and whatever filename encoding is used by the particular windows
+** installation.  Memory allocation errors are detected, but
+** they are reported back as [SQLITE_CANTOPEN] or
+** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
+**
+** INVARIANTS:
+**
+** {F17303}  The [sqlite3_malloc(N)] interface returns either a pointer to 
+**           newly checked-out block of at least N bytes of memory
+**           that is 8-byte aligned, 
+**           or it returns NULL if it is unable to fulfill the request.
+**
+** {F17304}  The [sqlite3_malloc(N)] interface returns a NULL pointer if
+**           N is less than or equal to zero.
+**
+** {F17305}  The [sqlite3_free(P)] interface releases memory previously
+**           returned from [sqlite3_malloc()] or [sqlite3_realloc()],
+**           making it available for reuse.
+**
+** {F17306}  A call to [sqlite3_free(NULL)] is a harmless no-op.
+**
+** {F17310}  A call to [sqlite3_realloc(0,N)] is equivalent to a call
+**           to [sqlite3_malloc(N)].
+**
+** {F17312}  A call to [sqlite3_realloc(P,0)] is equivalent to a call
+**           to [sqlite3_free(P)].
+**
+** {F17315}  The SQLite core uses [sqlite3_malloc()], [sqlite3_realloc()],
+**           and [sqlite3_free()] for all of its memory allocation and
+**           deallocation needs.
+**
+** {F17318}  The [sqlite3_realloc(P,N)] interface returns either a pointer
+**           to a block of checked-out memory of at least N bytes in size
+**           that is 8-byte aligned, or a NULL pointer.
+**
+** {F17321}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
+**           copies the first K bytes of content from P into the newly allocated
+**           where K is the lessor of N and the size of the buffer P.
+**
+** {F17322}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
+**           releases the buffer P.
+**
+** {F17323}  When [sqlite3_realloc(P,N)] returns NULL, the buffer P is
+**           not modified or released.
+**
+** LIMITATIONS:
+**
+** {U17350}  The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+**           must be either NULL or else a pointer obtained from a prior
+**           invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that has
+**           not been released.
+**
+** {U17351}  The application must not read or write any part of 
+**           a block of memory after it has been released using
+**           [sqlite3_free()] or [sqlite3_realloc()].
+**
+*/
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void sqlite3_free(void*);
+
+/*
+** CAPI3REF: Memory Allocator Statistics {F17370}
+**
+** SQLite provides these two interfaces for reporting on the status
+** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
+** the memory allocation subsystem included within the SQLite.
+**
+** INVARIANTS:
+**
+** {F17371} The [sqlite3_memory_used()] routine returns the
+**          number of bytes of memory currently outstanding 
+**          (malloced but not freed).
+**
+** {F17373} The [sqlite3_memory_highwater()] routine returns the maximum
+**          value of [sqlite3_memory_used()] 
+**          since the highwater mark was last reset.
+**
+** {F17374} The values returned by [sqlite3_memory_used()] and
+**          [sqlite3_memory_highwater()] include any overhead
+**          added by SQLite in its implementation of [sqlite3_malloc()],
+**          but not overhead added by the any underlying system library
+**          routines that [sqlite3_malloc()] may call.
+** 
+** {F17375} The memory highwater mark is reset to the current value of
+**          [sqlite3_memory_used()] if and only if the parameter to
+**          [sqlite3_memory_highwater()] is true.  The value returned
+**          by [sqlite3_memory_highwater(1)] is the highwater mark
+**          prior to the reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+
+/*
+** CAPI3REF: Pseudo-Random Number Generator {F17390}
+**
+** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
+** select random ROWIDs when inserting new records into a table that
+** already uses the largest possible ROWID.  The PRNG is also used for
+** the build-in random() and randomblob() SQL functions.  This interface allows
+** appliations to access the same PRNG for other purposes.
+**
+** A call to this routine stores N bytes of randomness into buffer P.
+**
+** The first time this routine is invoked (either internally or by
+** the application) the PRNG is seeded using randomness obtained
+** from the xRandomness method of the default [sqlite3_vfs] object.
+** On all subsequent invocations, the pseudo-randomness is generated
+** internally and without recourse to the [sqlite3_vfs] xRandomness
+** method.
+**
+** INVARIANTS:
+**
+** {F17392} The [sqlite3_randomness(N,P)] interface writes N bytes of
+**          high-quality pseudo-randomness into buffer P.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *P);
+
+/*
+** CAPI3REF: Compile-Time Authorization Callbacks {F12500}
+**
+** This routine registers a authorizer callback with a particular
+** [database connection], supplied in the first argument.
+** The authorizer callback is invoked as SQL statements are being compiled
+** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
+** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  At various
+** points during the compilation process, as logic is being created
+** to perform various actions, the authorizer callback is invoked to
+** see if those actions are allowed.  The authorizer callback should
+** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
+** specific action but allow the SQL statement to continue to be
+** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
+** rejected with an error.   If the authorizer callback returns
+** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
+** then [sqlite3_prepare_v2()] or equivalent call that triggered
+** the authorizer will fail with an error message.
+**
+** When the callback returns [SQLITE_OK], that means the operation
+** requested is ok.  When the callback returns [SQLITE_DENY], the
+** [sqlite3_prepare_v2()] or equivalent call that triggered the
+** authorizer will fail with an error message explaining that
+** access is denied.  If the authorizer code is [SQLITE_READ]
+** and the callback returns [SQLITE_IGNORE] then the
+** [prepared statement] statement is constructed to substitute
+** a NULL value in place of the table column that would have
+** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
+** return can be used to deny an untrusted user access to individual
+** columns of a table.
+**
+** The first parameter to the authorizer callback is a copy of
+** the third parameter to the sqlite3_set_authorizer() interface.
+** The second parameter to the callback is an integer 
+** [SQLITE_COPY | action code] that specifies the particular action
+** to be authorized. The third through sixth
+** parameters to the callback are zero-terminated strings that contain 
+** additional details about the action to be authorized.
+**
+** An authorizer is used when [sqlite3_prepare | preparing]
+** SQL statements from an untrusted
+** source, to ensure that the SQL statements do not try to access data
+** that they are not allowed to see, or that they do not try to
+** execute malicious statements that damage the database.  For
+** example, an application may allow a user to enter arbitrary
+** SQL queries for evaluation by a database.  But the application does
+** not want the user to be able to make arbitrary changes to the
+** database.  An authorizer could then be put in place while the
+** user-entered SQL is being [sqlite3_prepare | prepared] that
+** disallows everything except [SELECT] statements.
+**
+** Applications that need to process SQL from untrusted sources
+** might also consider lowering resource limits using [sqlite3_limit()]
+** and limiting database size using the [max_page_count] [PRAGMA]
+** in addition to using an authorizer.
+**
+** Only a single authorizer can be in place on a database connection
+** at a time.  Each call to sqlite3_set_authorizer overrides the
+** previous call.  Disable the authorizer by installing a NULL callback.
+** The authorizer is disabled by default.
+**
+** Note that the authorizer callback is invoked only during 
+** [sqlite3_prepare()] or its variants.  Authorization is not
+** performed during statement evaluation in [sqlite3_step()].
+**
+** INVARIANTS:
+**
+** {F12501} The [sqlite3_set_authorizer(D,...)] interface registers a
+**          authorizer callback with database connection D.
+**
+** {F12502} The authorizer callback is invoked as SQL statements are
+**          being compiled
+**
+** {F12503} If the authorizer callback returns any value other than
+**          [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] then
+**          the [sqlite3_prepare_v2()] or equivalent call that caused
+**          the authorizer callback to run shall fail with an
+**          [SQLITE_ERROR] error code and an appropriate error message.
+**
+** {F12504} When the authorizer callback returns [SQLITE_OK], the operation
+**          described is coded normally.
+**
+** {F12505} When the authorizer callback returns [SQLITE_DENY], the
+**          [sqlite3_prepare_v2()] or equivalent call that caused the
+**          authorizer callback to run shall fail
+**          with an [SQLITE_ERROR] error code and an error message
+**          explaining that access is denied.
+**
+** {F12506} If the authorizer code (the 2nd parameter to the authorizer
+**          callback) is [SQLITE_READ] and the authorizer callback returns
+**          [SQLITE_IGNORE] then the prepared statement is constructed to
+**          insert a NULL value in place of the table column that would have
+**          been read if [SQLITE_OK] had been returned.
+**
+** {F12507} If the authorizer code (the 2nd parameter to the authorizer
+**          callback) is anything other than [SQLITE_READ], then
+**          a return of [SQLITE_IGNORE] has the same effect as [SQLITE_DENY]. 
+**
+** {F12510} The first parameter to the authorizer callback is a copy of
+**          the third parameter to the [sqlite3_set_authorizer()] interface.
+**
+** {F12511} The second parameter to the callback is an integer 
+**          [SQLITE_COPY | action code] that specifies the particular action
+**          to be authorized.
+**
+** {F12512} The third through sixth parameters to the callback are
+**          zero-terminated strings that contain 
+**          additional details about the action to be authorized.
+**
+** {F12520} Each call to [sqlite3_set_authorizer()] overrides the
+**          any previously installed authorizer.
+**
+** {F12521} A NULL authorizer means that no authorization
+**          callback is invoked.
+**
+** {F12522} The default authorizer is NULL.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3*,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pUserData
+);
+
+/*
+** CAPI3REF: Authorizer Return Codes {F12590}
+**
+** The [sqlite3_set_authorizer | authorizer callback function] must
+** return either [SQLITE_OK] or one of these two constants in order
+** to signal SQLite whether or not the action is permitted.  See the
+** [sqlite3_set_authorizer | authorizer documentation] for additional
+** information.
+*/
+#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
+#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
+
+/*
+** CAPI3REF: Authorizer Action Codes {F12550}
+**
+** The [sqlite3_set_authorizer()] interface registers a callback function
+** that is invoked to authorizer certain SQL statement actions.  The
+** second parameter to the callback is an integer code that specifies
+** what action is being authorized.  These are the integer action codes that
+** the authorizer callback may be passed.
+**
+** These action code values signify what kind of operation is to be 
+** authorized.  The 3rd and 4th parameters to the authorization
+** callback function will be parameters or NULL depending on which of these
+** codes is used as the second parameter.  The 5th parameter to the
+** authorizer callback is the name of the database ("main", "temp", 
+** etc.) if applicable.  The 6th parameter to the authorizer callback
+** is the name of the inner-most trigger or view that is responsible for
+** the access attempt or NULL if this access attempt is directly from 
+** top-level SQL code.
+**
+** INVARIANTS:
+**
+** {F12551} The second parameter to an 
+**          [sqlite3_set_authorizer | authorizer callback is always an integer
+**          [SQLITE_COPY | authorizer code] that specifies what action
+**          is being authorized.
+**
+** {F12552} The 3rd and 4th parameters to the 
+**          [sqlite3_set_authorizer | authorization callback function]
+**          will be parameters or NULL depending on which 
+**          [SQLITE_COPY | authorizer code] is used as the second parameter.
+**
+** {F12553} The 5th parameter to the
+**          [sqlite3_set_authorizer | authorizer callback] is the name
+**          of the database (example: "main", "temp", etc.) if applicable.
+**
+** {F12554} The 6th parameter to the
+**          [sqlite3_set_authorizer | authorizer callback] is the name
+**          of the inner-most trigger or view that is responsible for
+**          the access attempt or NULL if this access attempt is directly from 
+**          top-level SQL code.
+*/
+/******************************************* 3rd ************ 4th ***********/
+#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
+#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
+#define SQLITE_DELETE                9   /* Table Name      NULL            */
+#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
+#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
+#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
+#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
+#define SQLITE_INSERT               18   /* Table Name      NULL            */
+#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
+#define SQLITE_READ                 20   /* Table Name      Column Name     */
+#define SQLITE_SELECT               21   /* NULL            NULL            */
+#define SQLITE_TRANSACTION          22   /* NULL            NULL            */
+#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
+#define SQLITE_ATTACH               24   /* Filename        NULL            */
+#define SQLITE_DETACH               25   /* Database Name   NULL            */
+#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
+#define SQLITE_REINDEX              27   /* Index Name      NULL            */
+#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
+#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
+#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
+#define SQLITE_FUNCTION             31   /* Function Name   NULL            */
+#define SQLITE_COPY                  0   /* No longer used */
+
+/*
+** CAPI3REF: Tracing And Profiling Functions {F12280}
+**
+** These routines register callback functions that can be used for
+** tracing and profiling the execution of SQL statements.
+**
+** The callback function registered by sqlite3_trace() is invoked at
+** various times when an SQL statement is being run by [sqlite3_step()].
+** The callback returns a UTF-8 rendering of the SQL statement text
+** as the statement first begins executing.  Additional callbacks occur
+** as each triggersubprogram is entered.  The callbacks for triggers
+** contain a UTF-8 SQL comment that identifies the trigger.
+** 
+** The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  The profile callback contains
+** the original statement text and an estimate of wall-clock time
+** of how long that statement took to run.
+**
+** The sqlite3_profile() API is currently considered experimental and
+** is subject to change or removal in a future release.
+**
+** The trigger reporting feature of the trace callback is considered
+** experimental and is subject to change or removal in future releases.
+** Future versions of SQLite might also add new trace callback 
+** invocations.
+**
+** INVARIANTS:
+**
+** {F12281} The callback function registered by [sqlite3_trace()] is
+**          whenever an SQL statement first begins to execute and
+**          whenever a trigger subprogram first begins to run.
+**
+** {F12282} Each call to [sqlite3_trace()] overrides the previously
+**          registered trace callback.
+**
+** {F12283} A NULL trace callback disables tracing.
+**
+** {F12284} The first argument to the trace callback is a copy of
+**          the pointer which was the 3rd argument to [sqlite3_trace()].
+**
+** {F12285} The second argument to the trace callback is a
+**          zero-terminated UTF8 string containing the original text
+**          of the SQL statement as it was passed into [sqlite3_prepare_v2()]
+**          or the equivalent, or an SQL comment indicating the beginning
+**          of a trigger subprogram.
+**
+** {F12287} The callback function registered by [sqlite3_profile()] is invoked
+**          as each SQL statement finishes.
+**
+** {F12288} The first parameter to the profile callback is a copy of
+**          the 3rd parameter to [sqlite3_profile()].
+**
+** {F12289} The second parameter to the profile callback is a
+**          zero-terminated UTF-8 string that contains the complete text of
+**          the SQL statement as it was processed by [sqlite3_prepare_v2()]
+**          or the equivalent.
+**
+** {F12290} The third parameter to the profile  callback is an estimate
+**          of the number of nanoseconds of wall-clock time required to
+**          run the SQL statement from start to finish.
+*/
+SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
+SQLITE_API void *sqlite3_profile(sqlite3*,
+   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
+
+/*
+** CAPI3REF: Query Progress Callbacks {F12910}
+**
+** This routine configures a callback function - the
+** progress callback - that is invoked periodically during long
+** running calls to [sqlite3_exec()], [sqlite3_step()] and
+** [sqlite3_get_table()].   An example use for this 
+** interface is to keep a GUI updated during a large query.
+**
+** If the progress callback returns non-zero, the opertion is
+** interrupted.  This feature can be used to implement a
+** "Cancel" button on a GUI dialog box.
+**
+** INVARIANTS:
+**
+** {F12911} The callback function registered by [sqlite3_progress_handler()]
+**          is invoked periodically during long running calls to
+**          [sqlite3_step()].
+**
+** {F12912} The progress callback is invoked once for every N virtual
+**          machine opcodes, where N is the second argument to 
+**          the [sqlite3_progress_handler()] call that registered
+**          the callback.  <todo>What if N is less than 1?</todo>
+**
+** {F12913} The progress callback itself is identified by the third
+**          argument to [sqlite3_progress_handler()].
+**
+** {F12914} The fourth argument [sqlite3_progress_handler()] is a
+***         void pointer passed to the progress callback
+**          function each time it is invoked.
+**
+** {F12915} If a call to [sqlite3_step()] results in fewer than
+**          N opcodes being executed,
+**          then the progress callback is never invoked. {END}
+** 
+** {F12916} Every call to [sqlite3_progress_handler()]
+**          overwrites any previously registere progress handler.
+**
+** {F12917} If the progress handler callback is NULL then no progress
+**          handler is invoked.
+**
+** {F12918} If the progress callback returns a result other than 0, then
+**          the behavior is a if [sqlite3_interrupt()] had been called.
+*/
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+
+/*
+** CAPI3REF: Opening A New Database Connection {F12700}
+**
+** These routines open an SQLite database file whose name
+** is given by the filename argument.
+** The filename argument is interpreted as UTF-8
+** for [sqlite3_open()] and [sqlite3_open_v2()] and as UTF-16
+** in the native byte order for [sqlite3_open16()].
+** An [sqlite3*] handle is usually returned in *ppDb, even
+** if an error occurs.  The only exception is if SQLite is unable
+** to allocate memory to hold the [sqlite3] object, a NULL will
+** be written into *ppDb instead of a pointer to the [sqlite3] object.
+** If the database is opened (and/or created)
+** successfully, then [SQLITE_OK] is returned.  Otherwise an
+** error code is returned.  The
+** [sqlite3_errmsg()] or [sqlite3_errmsg16()]  routines can be used to obtain
+** an English language description of the error.
+**
+** The default encoding for the database will be UTF-8 if
+** [sqlite3_open()] or [sqlite3_open_v2()] is called and
+** UTF-16 in the native byte order if [sqlite3_open16()] is used.
+**
+** Whether or not an error occurs when it is opened, resources
+** associated with the [sqlite3*] handle should be released by passing it
+** to [sqlite3_close()] when it is no longer required.
+**
+** The [sqlite3_open_v2()] interface works like [sqlite3_open()] 
+** except that it acccepts two additional parameters for additional control
+** over the new database connection.  The flags parameter can be
+** one of:
+**
+** <ol>
+** <li>  [SQLITE_OPEN_READONLY]
+** <li>  [SQLITE_OPEN_READWRITE]
+** <li>  [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]
+** </ol>
+**
+** The first value opens the database read-only. 
+** If the database does not previously exist, an error is returned.
+** The second option opens
+** the database for reading and writing if possible, or reading only if
+** if the file is write protected.  In either case the database
+** must already exist or an error is returned.  The third option
+** opens the database for reading and writing and creates it if it does
+** not already exist.
+** The third options is behavior that is always used for [sqlite3_open()]
+** and [sqlite3_open16()].
+**
+** If the 3rd parameter to [sqlite3_open_v2()] is not one of the
+** combinations shown above then the behavior is undefined.
+**
+** If the filename is ":memory:", then an private
+** in-memory database is created for the connection.  This in-memory
+** database will vanish when the database connection is closed.  Future
+** version of SQLite might make use of additional special filenames
+** that begin with the ":" character.  It is recommended that 
+** when a database filename really does begin with
+** ":" that you prefix the filename with a pathname like "./" to
+** avoid ambiguity.
+**
+** If the filename is an empty string, then a private temporary
+** on-disk database will be created.  This private database will be
+** automatically deleted as soon as the database connection is closed.
+**
+** The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system 
+** interface that the new database connection should use.  If the
+** fourth parameter is a NULL pointer then the default [sqlite3_vfs]
+** object is used.
+**
+** <b>Note to windows users:</b>  The encoding used for the filename argument
+** of [sqlite3_open()] and [sqlite3_open_v2()] must be UTF-8, not whatever
+** codepage is currently defined.  Filenames containing international
+** characters must be converted to UTF-8 prior to passing them into
+** [sqlite3_open()] or [sqlite3_open_v2()].
+**
+** INVARIANTS:
+**
+** {F12701} The [sqlite3_open()], [sqlite3_open16()], and
+**          [sqlite3_open_v2()] interfaces create a new
+**          [database connection] associated with
+**          the database file given in their first parameter.
+**
+** {F12702} The filename argument is interpreted as UTF-8
+**          for [sqlite3_open()] and [sqlite3_open_v2()] and as UTF-16
+**          in the native byte order for [sqlite3_open16()].
+**
+** {F12703} A successful invocation of [sqlite3_open()], [sqlite3_open16()], 
+**          or [sqlite3_open_v2()] writes a pointer to a new
+**          [database connection] into *ppDb.
+**
+** {F12704} The [sqlite3_open()], [sqlite3_open16()], and
+**          [sqlite3_open_v2()] interfaces return [SQLITE_OK] upon success,
+**          or an appropriate [error code] on failure.
+**
+** {F12706} The default text encoding for a new database created using
+**          [sqlite3_open()] or [sqlite3_open_v2()] will be UTF-8.
+**
+** {F12707} The default text encoding for a new database created using
+**          [sqlite3_open16()] will be UTF-16.
+**
+** {F12709} The [sqlite3_open(F,D)] interface is equivalent to
+**          [sqlite3_open_v2(F,D,G,0)] where the G parameter is
+**          [SQLITE_OPEN_READWRITE]|[SQLITE_OPEN_CREATE].
+**
+** {F12711} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
+**          bit value [SQLITE_OPEN_READONLY] then the database is opened
+**          for reading only.
+**
+** {F12712} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
+**          bit value [SQLITE_OPEN_READWRITE] then the database is opened
+**          reading and writing if possible, or for reading only if the
+**          file is write protected by the operating system.
+**
+** {F12713} If the G parameter to [sqlite3_open(v2(F,D,G,V)] omits the
+**          bit value [SQLITE_OPEN_CREATE] and the database does not
+**          previously exist, an error is returned.
+**
+** {F12714} If the G parameter to [sqlite3_open(v2(F,D,G,V)] contains the
+**          bit value [SQLITE_OPEN_CREATE] and the database does not
+**          previously exist, then an attempt is made to create and
+**          initialize the database.
+**
+** {F12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
+**          or [sqlite3_open_v2()] is ":memory:", then an private,
+**          ephemeral, in-memory database is created for the connection.
+**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
+**          in sqlite3_open_v2()?</todo>
+**
+** {F12719} If the filename is NULL or an empty string, then a private,
+**          ephermeral on-disk database will be created.
+**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
+**          in sqlite3_open_v2()?</todo>
+**
+** {F12721} The [database connection] created by 
+**          [sqlite3_open_v2(F,D,G,V)] will use the
+**          [sqlite3_vfs] object identified by the V parameter, or
+**          the default [sqlite3_vfs] object is V is a NULL pointer.
+*/
+SQLITE_API int sqlite3_open(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open16(
+  const void *filename,   /* Database filename (UTF-16) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+);
+
+/*
+** CAPI3REF: Error Codes And Messages {F12800}
+**
+** The sqlite3_errcode() interface returns the numeric
+** [SQLITE_OK | result code] or [SQLITE_IOERR_READ | extended result code]
+** for the most recent failed sqlite3_* API call associated
+** with [sqlite3] handle 'db'. If a prior API call failed but the
+** most recent API call succeeded, the return value from sqlite3_errcode()
+** is undefined.
+**
+** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** text that describes the error, as either UTF8 or UTF16 respectively.
+** Memory to hold the error message string is managed internally.
+** The application does not need to worry with freeing the result.
+** However, the error string might be overwritten or deallocated by
+** subsequent calls to other SQLite interface functions.
+**
+** INVARIANTS:
+**
+** {F12801} The [sqlite3_errcode(D)] interface returns the numeric
+**          [SQLITE_OK | result code] or
+**          [SQLITE_IOERR_READ | extended result code]
+**          for the most recently failed interface call associated
+**          with [database connection] D.
+**
+** {F12803} The [sqlite3_errmsg(D)] and [sqlite3_errmsg16(D)]
+**          interfaces return English-language text that describes
+**          the error in the mostly recently failed interface call,
+**          encoded as either UTF8 or UTF16 respectively.
+**
+** {F12807} The strings returned by [sqlite3_errmsg()] and [sqlite3_errmsg16()]
+**          are valid until the next SQLite interface call.
+**
+** {F12808} Calls to API routines that do not return an error code
+**          (example: [sqlite3_data_count()]) do not
+**          change the error code or message returned by
+**          [sqlite3_errcode()], [sqlite3_errmsg()], or [sqlite3_errmsg16()].
+**
+** {F12809} Interfaces that are not associated with a specific
+**          [database connection] (examples:
+**          [sqlite3_mprintf()] or [sqlite3_enable_shared_cache()]
+**          do not change the values returned by
+**          [sqlite3_errcode()], [sqlite3_errmsg()], or [sqlite3_errmsg16()].
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
+
+/*
+** CAPI3REF: SQL Statement Object {F13000}
+** KEYWORDS: {prepared statement} {prepared statements}
+**
+** An instance of this object represent single SQL statements.  This
+** object is variously known as a "prepared statement" or a 
+** "compiled SQL statement" or simply as a "statement".
+** 
+** The life of a statement object goes something like this:
+**
+** <ol>
+** <li> Create the object using [sqlite3_prepare_v2()] or a related
+**      function.
+** <li> Bind values to host parameters using
+**      [sqlite3_bind_blob | sqlite3_bind_* interfaces].
+** <li> Run the SQL by calling [sqlite3_step()] one or more times.
+** <li> Reset the statement using [sqlite3_reset()] then go back
+**      to step 2.  Do this zero or more times.
+** <li> Destroy the object using [sqlite3_finalize()].
+** </ol>
+**
+** Refer to documentation on individual methods above for additional
+** information.
+*/
+typedef struct sqlite3_stmt sqlite3_stmt;
+
+/*
+** CAPI3REF: Run-time Limits {F12760}
+**
+** This interface allows the size of various constructs to be limited
+** on a connection by connection basis.  The first parameter is the
+** [database connection] whose limit is to be set or queried.  The
+** second parameter is one of the [limit categories] that define a
+** class of constructs to be size limited.  The third parameter is the
+** new limit for that construct.  The function returns the old limit.
+**
+** If the new limit is a negative number, the limit is unchanged.
+** For the limit category of SQLITE_LIMIT_XYZ there is a hard upper
+** bound set by a compile-time C-preprocess macro named SQLITE_MAX_XYZ.
+** (The "_LIMIT_" in the name is changed to "_MAX_".)
+** Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper limit.
+**
+** Run time limits are intended for use in applications that manage
+** both their own internal database and also databases that are controlled
+** by untrusted external sources.  An example application might be a
+** webbrowser that has its own databases for storing history and
+** separate databases controlled by javascript applications downloaded
+** off the internet.  The internal databases can be given the
+** large, default limits.  Databases managed by external sources can
+** be given much smaller limits designed to prevent a denial of service
+** attach.  Developers might also want to use the [sqlite3_set_authorizer()]
+** interface to further control untrusted SQL.  The size of the database
+** created by an untrusted script can be contained using the
+** [max_page_count] [PRAGMA].
+**
+** This interface is currently considered experimental and is subject
+** to change or removal without prior notice.
+**
+** INVARIANTS:
+**
+** {F12762} A successful call to [sqlite3_limit(D,C,V)] where V is
+**          positive changes the
+**          limit on the size of construct C in [database connection] D
+**          to the lessor of V and the hard upper bound on the size
+**          of C that is set at compile-time.
+**
+** {F12766} A successful call to [sqlite3_limit(D,C,V)] where V is negative
+**          leaves the state of [database connection] D unchanged.
+**
+** {F12769} A successful call to [sqlite3_limit(D,C,V)] returns the
+**          value of the limit on the size of construct C in
+**          in [database connection] D as it was prior to the call.
+*/
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
+
+/*
+** CAPI3REF: Run-Time Limit Categories {F12790}
+** KEYWORDS: {limit category} {limit categories}
+** 
+** These constants define various aspects of a [database connection]
+** that can be limited in size by calls to [sqlite3_limit()].
+** The meanings of the various limits are as follows:
+**
+** <dl>
+** <dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any
+** string or blob or table row.<dd>
+**
+** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement.</dd>
+**
+** <dt>SQLITE_LIMIT_COLUMN</dt>
+** <dd>The maximum number of columns in a table definition or in the
+** result set of a SELECT or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>
+**
+** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>
+**
+** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>
+**
+** <dt>SQLITE_LIMIT_VDBE_OP</dt>
+** <dd>The maximum number of instructions in a virtual machine program
+** used to implement an SQL statement.</dd>
+**
+** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>
+**
+** <dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of attached databases.</dd>
+**
+** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the LIKE or
+** GLOB operators.</dd>
+**
+** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum number of variables in an SQL statement that can
+** be bound.</dd>
+** </dl>
+*/
+#define SQLITE_LIMIT_LENGTH                    0
+#define SQLITE_LIMIT_SQL_LENGTH                1
+#define SQLITE_LIMIT_COLUMN                    2
+#define SQLITE_LIMIT_EXPR_DEPTH                3
+#define SQLITE_LIMIT_COMPOUND_SELECT           4
+#define SQLITE_LIMIT_VDBE_OP                   5
+#define SQLITE_LIMIT_FUNCTION_ARG              6
+#define SQLITE_LIMIT_ATTACHED                  7
+#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
+#define SQLITE_LIMIT_VARIABLE_NUMBER           9
+
+/*
+** CAPI3REF: Compiling An SQL Statement {F13010}
+**
+** To execute an SQL query, it must first be compiled into a byte-code
+** program using one of these routines. 
+**
+** The first argument "db" is an [database connection] 
+** obtained from a prior call to [sqlite3_open()], [sqlite3_open_v2()]
+** or [sqlite3_open16()]. 
+** The second argument "zSql" is the statement to be compiled, encoded
+** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
+** interfaces uses UTF-8 and sqlite3_prepare16() and sqlite3_prepare16_v2()
+** use UTF-16. {END}
+**
+** If the nByte argument is less
+** than zero, then zSql is read up to the first zero terminator.
+** If nByte is non-negative, then it is the maximum number of 
+** bytes read from zSql.  When nByte is non-negative, the
+** zSql string ends at either the first '\000' or '\u0000' character or 
+** the nByte-th byte, whichever comes first. If the caller knows
+** that the supplied string is nul-terminated, then there is a small
+** performance advantage to be had by passing an nByte parameter that 
+** is equal to the number of bytes in the input string <i>including</i> 
+** the nul-terminator bytes.{END}
+**
+** *pzTail is made to point to the first byte past the end of the
+** first SQL statement in zSql.  These routines only compiles the first
+** statement in zSql, so *pzTail is left pointing to what remains
+** uncompiled.
+**
+** *ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  Or if there is an error, *ppStmt is
+** set to NULL.  If the input text contains no SQL (if the input
+** is and empty string or a comment) then *ppStmt is set to NULL.
+** {U13018} The calling procedure is responsible for deleting the
+** compiled SQL statement
+** using [sqlite3_finalize()] after it has finished with it.
+**
+** On success, [SQLITE_OK] is returned.  Otherwise an 
+** [error code] is returned.
+**
+** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
+** recommended for all new programs. The two older interfaces are retained
+** for backwards compatibility, but their use is discouraged.
+** In the "v2" interfaces, the prepared statement
+** that is returned (the [sqlite3_stmt] object) contains a copy of the 
+** original SQL text. {END} This causes the [sqlite3_step()] interface to
+** behave a differently in two ways:
+**
+** <ol>
+** <li>
+** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** always used to do, [sqlite3_step()] will automatically recompile the SQL
+** statement and try to run it again.  If the schema has changed in
+** a way that makes the statement no longer valid, [sqlite3_step()] will still
+** return [SQLITE_SCHEMA].  But unlike the legacy behavior, 
+** [SQLITE_SCHEMA] is now a fatal error.  Calling
+** [sqlite3_prepare_v2()] again will not make the
+** error go away.  Note: use [sqlite3_errmsg()] to find the text
+** of the parsing error that results in an [SQLITE_SCHEMA] return. {END}
+** </li>
+**
+** <li>
+** When an error occurs, 
+** [sqlite3_step()] will return one of the detailed 
+** [error codes] or [extended error codes]. 
+** The legacy behavior was that [sqlite3_step()] would only return a generic
+** [SQLITE_ERROR] result code and you would have to make a second call to
+** [sqlite3_reset()] in order to find the underlying cause of the problem.
+** With the "v2" prepare interfaces, the underlying reason for the error is
+** returned immediately.
+** </li>
+** </ol>
+**
+** INVARIANTS:
+**
+** {F13011} The [sqlite3_prepare(db,zSql,...)] and
+**          [sqlite3_prepare_v2(db,zSql,...)] interfaces interpret the
+**          text in their zSql parameter as UTF-8.
+**
+** {F13012} The [sqlite3_prepare16(db,zSql,...)] and
+**          [sqlite3_prepare16_v2(db,zSql,...)] interfaces interpret the
+**          text in their zSql parameter as UTF-16 in the native byte order.
+**
+** {F13013} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
+**          and its variants is less than zero, then SQL text is
+**          read from zSql is read up to the first zero terminator.
+**
+** {F13014} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
+**          and its variants is non-negative, then at most nBytes bytes
+**          SQL text is read from zSql.
+**
+** {F13015} In [sqlite3_prepare_v2(db,zSql,N,P,pzTail)] and its variants
+**          if the zSql input text contains more than one SQL statement
+**          and pzTail is not NULL, then *pzTail is made to point to the
+**          first byte past the end of the first SQL statement in zSql.
+**          <todo>What does *pzTail point to if there is one statement?</todo>
+**
+** {F13016} A successful call to [sqlite3_prepare_v2(db,zSql,N,ppStmt,...)]
+**          or one of its variants writes into *ppStmt a pointer to a new
+**          [prepared statement] or a pointer to NULL
+**          if zSql contains nothing other than whitespace or comments. 
+**
+** {F13019} The [sqlite3_prepare_v2()] interface and its variants return
+**          [SQLITE_OK] or an appropriate [error code] upon failure.
+**
+** {F13021} Before [sqlite3_prepare(db,zSql,nByte,ppStmt,pzTail)] or its
+**          variants returns an error (any value other than [SQLITE_OK])
+**          it first sets *ppStmt to NULL.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+
+/*
+** CAPIREF: Retrieving Statement SQL {F13100}
+**
+** This intereface can be used to retrieve a saved copy of the original
+** SQL text used to create a [prepared statement].
+**
+** INVARIANTS:
+**
+** {F13101} If the [prepared statement] passed as 
+**          the an argument to [sqlite3_sql()] was compiled
+**          compiled using either [sqlite3_prepare_v2()] or
+**          [sqlite3_prepare16_v2()],
+**          then [sqlite3_sql()] function returns a pointer to a
+**          zero-terminated string containing a UTF-8 rendering
+**          of the original SQL statement.
+**
+** {F13102} If the [prepared statement] passed as 
+**          the an argument to [sqlite3_sql()] was compiled
+**          compiled using either [sqlite3_prepare()] or
+**          [sqlite3_prepare16()],
+**          then [sqlite3_sql()] function returns a NULL pointer.
+**
+** {F13103} The string returned by [sqlite3_sql(S)] is valid until the
+**          [prepared statement] S is deleted using [sqlite3_finalize(S)].
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF:  Dynamically Typed Value Object  {F15000}
+** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
+**
+** SQLite uses the sqlite3_value object to represent all values
+** that can be stored in a database table.
+** SQLite uses dynamic typing for the values it stores.  
+** Values stored in sqlite3_value objects can be
+** be integers, floating point values, strings, BLOBs, or NULL.
+**
+** An sqlite3_value object may be either "protected" or "unprotected".
+** Some interfaces require a protected sqlite3_value.  Other interfaces
+** will accept either a protected or an unprotected sqlite3_value.
+** Every interface that accepts sqlite3_value arguments specifies 
+** whether or not it requires a protected sqlite3_value.
+**
+** The terms "protected" and "unprotected" refer to whether or not
+** a mutex is held.  A internal mutex is held for a protected
+** sqlite3_value object but no mutex is held for an unprotected
+** sqlite3_value object.  If SQLite is compiled to be single-threaded
+** (with SQLITE_THREADSAFE=0 and with [sqlite3_threadsafe()] returning 0)
+** then there is no distinction between
+** protected and unprotected sqlite3_value objects and they can be
+** used interchangable.  However, for maximum code portability it
+** is recommended that applications make the distinction between
+** between protected and unprotected sqlite3_value objects even if
+** they are single threaded.
+**
+** The sqlite3_value objects that are passed as parameters into the
+** implementation of application-defined SQL functions are protected.
+** The sqlite3_value object returned by
+** [sqlite3_column_value()] is unprotected.
+** Unprotected sqlite3_value objects may only be used with
+** [sqlite3_result_value()] and [sqlite3_bind_value()].  All other
+** interfaces that use sqlite3_value require protected sqlite3_value objects.
+*/
+typedef struct Mem sqlite3_value;
+
+/*
+** CAPI3REF:  SQL Function Context Object {F16001}
+**
+** The context in which an SQL function executes is stored in an
+** sqlite3_context object.  A pointer to an sqlite3_context
+** object is always first parameter to application-defined SQL functions.
+*/
+typedef struct sqlite3_context sqlite3_context;
+
+/*
+** CAPI3REF:  Binding Values To Prepared Statements {F13500}
+**
+** In the SQL strings input to [sqlite3_prepare_v2()] and its
+** variants, literals may be replace by a parameter in one
+** of these forms:
+**
+** <ul>
+** <li>  ?
+** <li>  ?NNN
+** <li>  :VVV
+** <li>  @VVV
+** <li>  $VVV
+** </ul>
+**
+** In the parameter forms shown above NNN is an integer literal,
+** VVV alpha-numeric parameter name.
+** The values of these parameters (also called "host parameter names"
+** or "SQL parameters")
+** can be set using the sqlite3_bind_*() routines defined here.
+**
+** The first argument to the sqlite3_bind_*() routines always
+** is a pointer to the [sqlite3_stmt] object returned from
+** [sqlite3_prepare_v2()] or its variants. The second
+** argument is the index of the parameter to be set. The
+** first parameter has an index of 1.  When the same named
+** parameter is used more than once, second and subsequent
+** occurrences have the same index as the first occurrence. 
+** The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_name()] API if desired.  The index
+** for "?NNN" parameters is the value of NNN.
+** The NNN value must be between 1 and the compile-time
+** parameter SQLITE_MAX_VARIABLE_NUMBER (default value: 999).
+**
+** The third argument is the value to bind to the parameter.
+**
+** In those
+** routines that have a fourth argument, its value is the number of bytes
+** in the parameter.  To be clear: the value is the number of <u>bytes</u>
+** in the value, not the number of characters. 
+** If the fourth parameter is negative, the length of the string is
+** number of bytes up to the first zero terminator.
+**
+** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
+** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
+** string after SQLite has finished with it. If the fifth argument is
+** the special value [SQLITE_STATIC], then SQLite assumes that the
+** information is in static, unmanaged space and does not need to be freed.
+** If the fifth argument has the value [SQLITE_TRANSIENT], then
+** SQLite makes its own private copy of the data immediately, before
+** the sqlite3_bind_*() routine returns.
+**
+** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeros.  A zeroblob uses a fixed amount of memory
+** (just an integer to hold it size) while it is being processed.
+** Zeroblobs are intended to serve as place-holders for BLOBs whose
+** content is later written using 
+** [sqlite3_blob_open | increment BLOB I/O] routines. A negative
+** value for the zeroblob results in a zero-length BLOB.
+**
+** The sqlite3_bind_*() routines must be called after
+** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
+** before [sqlite3_step()].
+** Bindings are not cleared by the [sqlite3_reset()] routine.
+** Unbound parameters are interpreted as NULL.
+**
+** These routines return [SQLITE_OK] on success or an error code if
+** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
+** index is out of range.  [SQLITE_NOMEM] is returned if malloc fails.
+** [SQLITE_MISUSE] might be returned if these routines are called on a
+** virtual machine that is the wrong state or which has already been finalized.
+** Detection of misuse is unreliable.  Applications should not depend
+** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
+** a logic error in the application.  Future versions of SQLite might
+** panic rather than return SQLITE_MISUSE.
+**
+** See also: [sqlite3_bind_parameter_count()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+**
+** INVARIANTS:
+**
+** {F13506} The [sqlite3_prepare | SQL statement compiler] recognizes
+**          tokens of the forms "?", "?NNN", "$VVV", ":VVV", and "@VVV"
+**          as SQL parameters, where NNN is any sequence of one or more
+**          digits and where VVV is any sequence of one or more 
+**          alphanumeric characters or "::" optionally followed by
+**          a string containing no spaces and contained within parentheses.
+**
+** {F13509} The initial value of an SQL parameter is NULL.
+**
+** {F13512} The index of an "?" SQL parameter is one larger than the
+**          largest index of SQL parameter to the left, or 1 if
+**          the "?" is the leftmost SQL parameter.
+**
+** {F13515} The index of an "?NNN" SQL parameter is the integer NNN.
+**
+** {F13518} The index of an ":VVV", "$VVV", or "@VVV" SQL parameter is
+**          the same as the index of leftmost occurances of the same
+**          parameter, or one more than the largest index over all
+**          parameters to the left if this is the first occurrance
+**          of this parameter, or 1 if this is the leftmost parameter.
+**
+** {F13521} The [sqlite3_prepare | SQL statement compiler] fail with
+**          an [SQLITE_RANGE] error if the index of an SQL parameter
+**          is less than 1 or greater than SQLITE_MAX_VARIABLE_NUMBER.
+**
+** {F13524} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,V,...)]
+**          associate the value V with all SQL parameters having an
+**          index of N in the [prepared statement] S.
+**
+** {F13527} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,...)]
+**          override prior calls with the same values of S and N.
+**
+** {F13530} Bindings established by [sqlite3_bind_text | sqlite3_bind(S,...)]
+**          persist across calls to [sqlite3_reset(S)].
+**
+** {F13533} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
+**          [sqlite3_bind_text(S,N,V,L,D)], or
+**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds the first L
+**          bytes of the blob or string pointed to by V, when L
+**          is non-negative.
+**
+** {F13536} In calls to [sqlite3_bind_text(S,N,V,L,D)] or
+**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds characters
+**          from V through the first zero character when L is negative.
+**
+** {F13539} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
+**          [sqlite3_bind_text(S,N,V,L,D)], or
+**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
+**          constant [SQLITE_STATIC], SQLite assumes that the value V
+**          is held in static unmanaged space that will not change
+**          during the lifetime of the binding.
+**
+** {F13542} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
+**          [sqlite3_bind_text(S,N,V,L,D)], or
+**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
+**          constant [SQLITE_TRANSIENT], the routine makes a 
+**          private copy of V value before it returns.
+**
+** {F13545} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
+**          [sqlite3_bind_text(S,N,V,L,D)], or
+**          [sqlite3_bind_text16(S,N,V,L,D)] when D is a pointer to
+**          a function, SQLite invokes that function to destroy the
+**          V value after it has finished using the V value.
+**
+** {F13548} In calls to [sqlite3_bind_zeroblob(S,N,V,L)] the value bound
+**          is a blob of L bytes, or a zero-length blob if L is negative.
+**
+** {F13551} In calls to [sqlite3_bind_value(S,N,V)] the V argument may
+**          be either a [protected sqlite3_value] object or an
+**          [unprotected sqlite3_value] object.
+*/
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+
+/*
+** CAPI3REF: Number Of SQL Parameters {F13600}
+**
+** This routine can be used to find the number of SQL parameters
+** in a prepared statement.  SQL parameters are tokens of the
+** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
+** place-holders for values that are [sqlite3_bind_blob | bound]
+** to the parameters at a later time.
+**
+** This routine actually returns the index of the largest parameter.
+** For all forms except ?NNN, this will correspond to the number of
+** unique parameters.  If parameters of the ?NNN are used, there may
+** be gaps in the list.
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+**
+** INVARIANTS:
+**
+** {F13601} The [sqlite3_bind_parameter_count(S)] interface returns
+**          the largest index of all SQL parameters in the
+**          [prepared statement] S, or 0 if S
+**          contains no SQL parameters.
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Name Of A Host Parameter {F13620}
+**
+** This routine returns a pointer to the name of the n-th
+** SQL parameter in a [prepared statement].
+** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** respectively.
+** In other words, the initial ":" or "$" or "@" or "?"
+** is included as part of the name.
+** Parameters of the form "?" without a following integer have no name.
+**
+** The first host parameter has an index of 1, not 0.
+**
+** If the value n is out of range or if the n-th parameter is
+** nameless, then NULL is returned.  The returned string is
+** always in the UTF-8 encoding even if the named parameter was
+** originally specified as UTF-16 in [sqlite3_prepare16()] or
+** [sqlite3_prepare16_v2()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+**
+** INVARIANTS:
+**
+** {F13621} The [sqlite3_bind_parameter_name(S,N)] interface returns
+**          a UTF-8 rendering of the name of the SQL parameter in
+**          [prepared statement] S having index N, or
+**          NULL if there is no SQL parameter with index N or if the
+**          parameter with index N is an anonymous parameter "?".
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+
+/*
+** CAPI3REF: Index Of A Parameter With A Given Name {F13640}
+**
+** Return the index of an SQL parameter given its name.  The
+** index value returned is suitable for use as the second
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  A zero
+** is returned if no matching parameter is found.  The parameter
+** name must be given in UTF-8 even if the original statement
+** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+**
+** INVARIANTS:
+**
+** {F13641} The [sqlite3_bind_parameter_index(S,N)] interface returns
+**          the index of SQL parameter in [prepared statement]
+**          S whose name matches the UTF-8 string N, or 0 if there is
+**          no match.
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+
+/*
+** CAPI3REF: Reset All Bindings On A Prepared Statement {F13660}
+**
+** Contrary to the intuition of many, [sqlite3_reset()] does not
+** reset the [sqlite3_bind_blob | bindings] on a 
+** [prepared statement].  Use this routine to
+** reset all host parameters to NULL.
+**
+** INVARIANTS:
+**
+** {F13661} The [sqlite3_clear_bindings(S)] interface resets all
+**          SQL parameter bindings in [prepared statement] S
+**          back to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number Of Columns In A Result Set {F13710}
+**
+** Return the number of columns in the result set returned by the 
+** [prepared statement]. This routine returns 0
+** if pStmt is an SQL statement that does not return data (for 
+** example an UPDATE).
+**
+** INVARIANTS:
+**
+** {F13711} The [sqlite3_column_count(S)] interface returns the number of
+**          columns in the result set generated by the
+**          [prepared statement] S, or 0 if S does not generate
+**          a result set.
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Column Names In A Result Set {F13720}
+**
+** These routines return the name assigned to a particular column
+** in the result set of a SELECT statement.  The sqlite3_column_name()
+** interface returns a pointer to a zero-terminated UTF8 string
+** and sqlite3_column_name16() returns a pointer to a zero-terminated
+** UTF16 string.  The first parameter is the
+** [prepared statement] that implements the SELECT statement.
+** The second parameter is the column number.  The left-most column is
+** number 0.
+**
+** The returned string pointer is valid until either the 
+** [prepared statement] is destroyed by [sqlite3_finalize()]
+** or until the next call sqlite3_column_name() or sqlite3_column_name16()
+** on the same column.
+**
+** If sqlite3_malloc() fails during the processing of either routine
+** (for example during a conversion from UTF-8 to UTF-16) then a
+** NULL pointer is returned.
+**
+** The name of a result column is the value of the "AS" clause for
+** that column, if there is an AS clause.  If there is no AS clause
+** then the name of the column is unspecified and may change from
+** one release of SQLite to the next.
+**
+** INVARIANTS:
+**
+** {F13721} A successful invocation of the [sqlite3_column_name(S,N)]
+**          interface returns the name
+**          of the Nth column (where 0 is the left-most column) for the
+**          result set of [prepared statement] S as a
+**          zero-terminated UTF-8 string.
+**
+** {F13723} A successful invocation of the [sqlite3_column_name16(S,N)]
+**          interface returns the name
+**          of the Nth column (where 0 is the left-most column) for the
+**          result set of [prepared statement] S as a
+**          zero-terminated UTF-16 string in the native byte order.
+**
+** {F13724} The [sqlite3_column_name()] and [sqlite3_column_name16()]
+**          interfaces return a NULL pointer if they are unable to
+**          allocate memory memory to hold there normal return strings.
+**
+** {F13725} If the N parameter to [sqlite3_column_name(S,N)] or
+**          [sqlite3_column_name16(S,N)] is out of range, then the
+**          interfaces returns a NULL pointer.
+** 
+** {F13726} The strings returned by [sqlite3_column_name(S,N)] and
+**          [sqlite3_column_name16(S,N)] are valid until the next
+**          call to either routine with the same S and N parameters
+**          or until [sqlite3_finalize(S)] is called.
+**
+** {F13727} When a result column of a [SELECT] statement contains
+**          an AS clause, the name of that column is the indentifier
+**          to the right of the AS keyword.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+
+/*
+** CAPI3REF: Source Of Data In A Query Result {F13740}
+**
+** These routines provide a means to determine what column of what
+** table in which database a result of a SELECT statement comes from.
+** The name of the database or table or column can be returned as
+** either a UTF8 or UTF16 string.  The _database_ routines return
+** the database name, the _table_ routines return the table name, and
+** the origin_ routines return the column name.
+** The returned string is valid until
+** the [prepared statement] is destroyed using
+** [sqlite3_finalize()] or until the same information is requested
+** again in a different encoding.
+**
+** The names returned are the original un-aliased names of the
+** database, table, and column.
+**
+** The first argument to the following calls is a [prepared statement].
+** These functions return information about the Nth column returned by 
+** the statement, where N is the second function argument.
+**
+** If the Nth column returned by the statement is an expression
+** or subquery and is not a column value, then all of these functions
+** return NULL.  These routine might also return NULL if a memory
+** allocation error occurs.  Otherwise, they return the 
+** name of the attached database, table and column that query result
+** column was extracted from.
+**
+** As with all other SQLite APIs, those postfixed with "16" return
+** UTF-16 encoded strings, the other functions return UTF-8. {END}
+**
+** These APIs are only available if the library was compiled with the 
+** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
+**
+** {U13751}
+** If two or more threads call one or more of these routines against the same
+** prepared statement and column at the same time then the results are
+** undefined.
+**
+** INVARIANTS:
+**
+** {F13741} The [sqlite3_column_database_name(S,N)] interface returns either
+**          the UTF-8 zero-terminated name of the database from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13742} The [sqlite3_column_database_name16(S,N)] interface returns either
+**          the UTF-16 native byte order
+**          zero-terminated name of the database from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13743} The [sqlite3_column_table_name(S,N)] interface returns either
+**          the UTF-8 zero-terminated name of the table from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13744} The [sqlite3_column_table_name16(S,N)] interface returns either
+**          the UTF-16 native byte order
+**          zero-terminated name of the table from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13745} The [sqlite3_column_origin_name(S,N)] interface returns either
+**          the UTF-8 zero-terminated name of the table column from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13746} The [sqlite3_column_origin_name16(S,N)] interface returns either
+**          the UTF-16 native byte order
+**          zero-terminated name of the table column from which the 
+**          Nth result column of [prepared statement] S 
+**          is extracted, or NULL if the the Nth column of S is a
+**          general expression or if unable to allocate memory
+**          to store the name.
+**          
+** {F13748} The return values from
+**          [sqlite3_column_database_name|column metadata interfaces]
+**          are valid
+**          for the lifetime of the [prepared statement]
+**          or until the encoding is changed by another metadata
+**          interface call for the same prepared statement and column.
+**
+** LIMITATIONS:
+**
+** {U13751} If two or more threads call one or more
+**          [sqlite3_column_database_name|column metadata interfaces]
+**          the same [prepared statement] and result column
+**          at the same time then the results are undefined.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Declared Datatype Of A Query Result {F13760}
+**
+** The first parameter is a [prepared statement]. 
+** If this statement is a SELECT statement and the Nth column of the 
+** returned result set of that SELECT is a table column (not an
+** expression or subquery) then the declared type of the table
+** column is returned.  If the Nth column of the result set is an
+** expression or subquery, then a NULL pointer is returned.
+** The returned string is always UTF-8 encoded.  {END} 
+** For example, in the database schema:
+**
+** CREATE TABLE t1(c1 VARIANT);
+**
+** And the following statement compiled:
+**
+** SELECT c1 + 1, c1 FROM t1;
+**
+** Then this routine would return the string "VARIANT" for the second
+** result column (i==1), and a NULL pointer for the first result column
+** (i==0).
+**
+** SQLite uses dynamic run-time typing.  So just because a column
+** is declared to contain a particular type does not mean that the
+** data stored in that column is of the declared type.  SQLite is
+** strongly typed, but the typing is dynamic not static.  Type
+** is associated with individual values, not with the containers
+** used to hold those values.
+**
+** INVARIANTS:
+**
+** {F13761}  A successful call to [sqlite3_column_decltype(S,N)]
+**           returns a zero-terminated UTF-8 string containing the
+**           the declared datatype of the table column that appears
+**           as the Nth column (numbered from 0) of the result set to the
+**           [prepared statement] S.
+**
+** {F13762}  A successful call to [sqlite3_column_decltype16(S,N)]
+**           returns a zero-terminated UTF-16 native byte order string
+**           containing the declared datatype of the table column that appears
+**           as the Nth column (numbered from 0) of the result set to the
+**           [prepared statement] S.
+**
+** {F13763}  If N is less than 0 or N is greater than or equal to
+**           the number of columns in [prepared statement] S
+**           or if the Nth column of S is an expression or subquery rather
+**           than a table column or if a memory allocation failure
+**           occurs during encoding conversions, then
+**           calls to [sqlite3_column_decltype(S,N)] or
+**           [sqlite3_column_decltype16(S,N)] return NULL.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+
+/* 
+** CAPI3REF:  Evaluate An SQL Statement {F13200}
+**
+** After an [prepared statement] has been prepared with a call
+** to either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or to one of
+** the legacy interfaces [sqlite3_prepare()] or [sqlite3_prepare16()],
+** then this function must be called one or more times to evaluate the 
+** statement.
+**
+** The details of the behavior of this sqlite3_step() interface depend
+** on whether the statement was prepared using the newer "v2" interface
+** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
+** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
+** new "v2" interface is recommended for new applications but the legacy
+** interface will continue to be supported.
+**
+** In the legacy interface, the return value will be either [SQLITE_BUSY], 
+** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
+** With the "v2" interface, any of the other [SQLITE_OK | result code]
+** or [SQLITE_IOERR_READ | extended result code] might be returned as
+** well.
+**
+** [SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  If the statement is a COMMIT
+** or occurs outside of an explicit transaction, then you can retry the
+** statement.  If the statement is not a COMMIT and occurs within a
+** explicit transaction then you should rollback the transaction before
+** continuing.
+**
+** [SQLITE_DONE] means that the statement has finished executing
+** successfully.  sqlite3_step() should not be called again on this virtual
+** machine without first calling [sqlite3_reset()] to reset the virtual
+** machine back to its initial state.
+**
+** If the SQL statement being executed returns any data, then 
+** [SQLITE_ROW] is returned each time a new row of data is ready
+** for processing by the caller. The values may be accessed using
+** the [sqlite3_column_int | column access functions].
+** sqlite3_step() is called again to retrieve the next row of data.
+** 
+** [SQLITE_ERROR] means that a run-time error (such as a constraint
+** violation) has occurred.  sqlite3_step() should not be called again on
+** the VM. More information may be found by calling [sqlite3_errmsg()].
+** With the legacy interface, a more specific error code (example:
+** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
+** can be obtained by calling [sqlite3_reset()] on the
+** [prepared statement].  In the "v2" interface,
+** the more specific error code is returned directly by sqlite3_step().
+**
+** [SQLITE_MISUSE] means that the this routine was called inappropriately.
+** Perhaps it was called on a [prepared statement] that has
+** already been [sqlite3_finalize | finalized] or on one that had 
+** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
+** be the case that the same database connection is being used by two or
+** more threads at the same moment in time.
+**
+** <b>Goofy Interface Alert:</b>
+** In the legacy interface, 
+** the sqlite3_step() API always returns a generic error code,
+** [SQLITE_ERROR], following any error other than [SQLITE_BUSY]
+** and [SQLITE_MISUSE].  You must call [sqlite3_reset()] or
+** [sqlite3_finalize()] in order to find one of the specific
+** [error codes] that better describes the error.
+** We admit that this is a goofy design.  The problem has been fixed
+** with the "v2" interface.  If you prepare all of your SQL statements
+** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
+** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()], then the 
+** more specific [error codes] are returned directly
+** by sqlite3_step().  The use of the "v2" interface is recommended.
+**
+** INVARIANTS:
+**
+** {F13202}  If [prepared statement] S is ready to be
+**           run, then [sqlite3_step(S)] advances that prepared statement
+**           until to completion or until it is ready to return another
+**           row of the result set or an interrupt or run-time error occurs.
+**
+** {F15304}  When a call to [sqlite3_step(S)] causes the 
+**           [prepared statement] S to run to completion,
+**           the function returns [SQLITE_DONE].
+**
+** {F15306}  When a call to [sqlite3_step(S)] stops because it is ready
+**           to return another row of the result set, it returns
+**           [SQLITE_ROW].
+**
+** {F15308}  If a call to [sqlite3_step(S)] encounters an
+**           [sqlite3_interrupt|interrupt] or a run-time error,
+**           it returns an appropraite error code that is not one of
+**           [SQLITE_OK], [SQLITE_ROW], or [SQLITE_DONE].
+**
+** {F15310}  If an [sqlite3_interrupt|interrupt] or run-time error
+**           occurs during a call to [sqlite3_step(S)]
+**           for a [prepared statement] S created using
+**           legacy interfaces [sqlite3_prepare()] or
+**           [sqlite3_prepare16()] then the function returns either
+**           [SQLITE_ERROR], [SQLITE_BUSY], or [SQLITE_MISUSE].
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number of columns in a result set {F13770}
+**
+** Return the number of values in the current row of the result set.
+**
+** INVARIANTS:
+**
+** {F13771}  After a call to [sqlite3_step(S)] that returns
+**           [SQLITE_ROW], the [sqlite3_data_count(S)] routine
+**           will return the same value as the
+**           [sqlite3_column_count(S)] function.
+**
+** {F13772}  After [sqlite3_step(S)] has returned any value other than
+**           [SQLITE_ROW] or before [sqlite3_step(S)] has been 
+**           called on the [prepared statement] for
+**           the first time since it was [sqlite3_prepare|prepared]
+**           or [sqlite3_reset|reset], the [sqlite3_data_count(S)]
+**           routine returns zero.
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Fundamental Datatypes {F10265}
+** KEYWORDS: SQLITE_TEXT
+**
+** {F10266}Every value in SQLite has one of five fundamental datatypes:
+**
+** <ul>
+** <li> 64-bit signed integer
+** <li> 64-bit IEEE floating point number
+** <li> string
+** <li> BLOB
+** <li> NULL
+** </ul> {END}
+**
+** These constants are codes for each of those types.
+**
+** Note that the SQLITE_TEXT constant was also used in SQLite version 2
+** for a completely different meaning.  Software that links against both
+** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT not
+** SQLITE_TEXT.
+*/
+#define SQLITE_INTEGER  1
+#define SQLITE_FLOAT    2
+#define SQLITE_BLOB     4
+#define SQLITE_NULL     5
+#ifdef SQLITE_TEXT
+# undef SQLITE_TEXT
+#else
+# define SQLITE_TEXT     3
+#endif
+#define SQLITE3_TEXT     3
+
+/*
+** CAPI3REF: Results Values From A Query {F13800}
+**
+** These routines form the "result set query" interface.
+**
+** These routines return information about
+** a single column of the current result row of a query.  In every
+** case the first argument is a pointer to the 
+** [prepared statement] that is being
+** evaluated (the [sqlite3_stmt*] that was returned from 
+** [sqlite3_prepare_v2()] or one of its variants) and
+** the second argument is the index of the column for which information 
+** should be returned.  The left-most column of the result set
+** has an index of 0.
+**
+** If the SQL statement is not currently point to a valid row, or if the
+** the column index is out of range, the result is undefined. 
+** These routines may only be called when the most recent call to
+** [sqlite3_step()] has returned [SQLITE_ROW] and neither
+** [sqlite3_reset()] nor [sqlite3_finalize()] has been call subsequently.
+** If any of these routines are called after [sqlite3_reset()] or
+** [sqlite3_finalize()] or after [sqlite3_step()] has returned
+** something other than [SQLITE_ROW], the results are undefined.
+** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
+** are called from a different thread while any of these routines
+** are pending, then the results are undefined.  
+**
+** The sqlite3_column_type() routine returns 
+** [SQLITE_INTEGER | datatype code] for the initial data type
+** of the result column.  The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
+** returned by sqlite3_column_type() is only meaningful if no type
+** conversions have occurred as described below.  After a type conversion,
+** the value returned by sqlite3_column_type() is undefined.  Future
+** versions of SQLite may change the behavior of sqlite3_column_type()
+** following a type conversion.
+**
+** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 
+** routine returns the number of bytes in that BLOB or string.
+** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** the string to UTF-8 and then returns the number of bytes.
+** If the result is a numeric value then sqlite3_column_bytes() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
+** the number of bytes in that string.
+** The value returned does not include the zero terminator at the end
+** of the string.  For clarity: the value returned is the number of
+** bytes in the string, not the number of characters.
+**
+** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero terminated.  The return
+** value from sqlite3_column_blob() for a zero-length blob is an arbitrary
+** pointer, possibly even a NULL pointer.
+**
+** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
+** but leaves the result in UTF-16 in native byte order instead of UTF-8.  
+** The zero terminator is not included in this count.
+**
+** The object returned by [sqlite3_column_value()] is an
+** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
+** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
+** If the [unprotected sqlite3_value] object returned by
+** [sqlite3_column_value()] is used in any other way, including calls
+** to routines like 
+** [sqlite3_value_int()], [sqlite3_value_text()], or [sqlite3_value_bytes()],
+** then the behavior is undefined.
+**
+** These routines attempt to convert the value where appropriate.  For
+** example, if the internal representation is FLOAT and a text result
+** is requested, [sqlite3_snprintf()] is used internally to do the conversion
+** automatically.  The following table details the conversions that
+** are applied:
+**
+** <blockquote>
+** <table border="1">
+** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
+**
+** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
+** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
+** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
+** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
+** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
+** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
+** <tr><td> INTEGER  <td>   BLOB    <td> Same as for INTEGER->TEXT
+** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
+** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
+** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
+** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
+** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
+** <tr><td>  TEXT    <td>   BLOB    <td> No change
+** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
+** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
+** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
+** </table>
+** </blockquote>
+**
+** The table above makes reference to standard C library functions atoi()
+** and atof().  SQLite does not really use these functions.  It has its
+** on equavalent internal routines.  The atoi() and atof() names are
+** used in the table for brevity and because they are familiar to most
+** C programmers.
+**
+** Note that when type conversions occur, pointers returned by prior
+** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
+** sqlite3_column_text16() may be invalidated. 
+** Type conversions and pointer invalidations might occur
+** in the following cases:
+**
+** <ul>
+** <li><p>  The initial content is a BLOB and sqlite3_column_text() 
+**          or sqlite3_column_text16() is called.  A zero-terminator might
+**          need to be added to the string.</p></li>
+**
+** <li><p>  The initial content is UTF-8 text and sqlite3_column_bytes16() or
+**          sqlite3_column_text16() is called.  The content must be converted
+**          to UTF-16.</p></li>
+**
+** <li><p>  The initial content is UTF-16 text and sqlite3_column_bytes() or
+**          sqlite3_column_text() is called.  The content must be converted
+**          to UTF-8.</p></li>
+** </ul>
+**
+** Conversions between UTF-16be and UTF-16le are always done in place and do
+** not invalidate a prior pointer, though of course the content of the buffer
+** that the prior pointer points to will have been modified.  Other kinds
+** of conversion are done in place when it is possible, but sometime it is
+** not possible and in those cases prior pointers are invalidated.  
+**
+** The safest and easiest to remember policy is to invoke these routines
+** in one of the following ways:
+**
+**  <ul>
+**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
+**  </ul>
+**
+** In other words, you should call sqlite3_column_text(), sqlite3_column_blob(),
+** or sqlite3_column_text16() first to force the result into the desired
+** format, then invoke sqlite3_column_bytes() or sqlite3_column_bytes16() to
+** find the size of the result.  Do not mix call to sqlite3_column_text() or
+** sqlite3_column_blob() with calls to sqlite3_column_bytes16().  And do not
+** mix calls to sqlite3_column_text16() with calls to sqlite3_column_bytes().
+**
+** The pointers returned are valid until a type conversion occurs as
+** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
+** [sqlite3_finalize()] is called.  The memory space used to hold strings
+** and blobs is freed automatically.  Do <b>not</b> pass the pointers returned
+** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 
+** [sqlite3_free()].
+**
+** If a memory allocation error occurs during the evaluation of any
+** of these routines, a default value is returned.  The default value
+** is either the integer 0, the floating point number 0.0, or a NULL
+** pointer.  Subsequent calls to [sqlite3_errcode()] will return
+** [SQLITE_NOMEM].
+**
+** INVARIANTS:
+**
+** {F13803} The [sqlite3_column_blob(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a blob and then returns a
+**          pointer to the converted value.
+**
+** {F13806} The [sqlite3_column_bytes(S,N)] interface returns the
+**          number of bytes in the blob or string (exclusive of the
+**          zero terminator on the string) that was returned by the
+**          most recent call to [sqlite3_column_blob(S,N)] or
+**          [sqlite3_column_text(S,N)].
+**
+** {F13809} The [sqlite3_column_bytes16(S,N)] interface returns the
+**          number of bytes in the string (exclusive of the
+**          zero terminator on the string) that was returned by the
+**          most recent call to [sqlite3_column_text16(S,N)].
+**
+** {F13812} The [sqlite3_column_double(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a floating point value and
+**          returns a copy of that value.
+**
+** {F13815} The [sqlite3_column_int(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a 64-bit signed integer and
+**          returns the lower 32 bits of that integer.
+**
+** {F13818} The [sqlite3_column_int64(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a 64-bit signed integer and
+**          returns a copy of that integer.
+**
+** {F13821} The [sqlite3_column_text(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a zero-terminated UTF-8 
+**          string and returns a pointer to that string.
+**
+** {F13824} The [sqlite3_column_text16(S,N)] interface converts the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S into a zero-terminated 2-byte
+**          aligned UTF-16 native byte order
+**          string and returns a pointer to that string.
+**
+** {F13827} The [sqlite3_column_type(S,N)] interface returns
+**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
+**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
+**          the Nth column in the current row of the result set for
+**          [prepared statement] S.
+**
+** {F13830} The [sqlite3_column_value(S,N)] interface returns a
+**          pointer to an [unprotected sqlite3_value] object for the
+**          Nth column in the current row of the result set for
+**          [prepared statement] S.
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+
+/*
+** CAPI3REF: Destroy A Prepared Statement Object {F13300}
+**
+** The sqlite3_finalize() function is called to delete a 
+** [prepared statement]. If the statement was
+** executed successfully, or not executed at all, then SQLITE_OK is returned.
+** If execution of the statement failed then an 
+** [error code] or [extended error code]
+** is returned. 
+**
+** This routine can be called at any point during the execution of the
+** [prepared statement].  If the virtual machine has not 
+** completed execution when this routine is called, that is like
+** encountering an error or an interrupt.  (See [sqlite3_interrupt()].) 
+** Incomplete updates may be rolled back and transactions cancelled,  
+** depending on the circumstances, and the 
+** [error code] returned will be [SQLITE_ABORT].
+**
+** INVARIANTS:
+**
+** {F11302} The [sqlite3_finalize(S)] interface destroys the
+**          [prepared statement] S and releases all
+**          memory and file resources held by that object.
+**
+** {F11304} If the most recent call to [sqlite3_step(S)] for the
+**          [prepared statement] S returned an error,
+**          then [sqlite3_finalize(S)] returns that same error.
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Reset A Prepared Statement Object {F13330}
+**
+** The sqlite3_reset() function is called to reset a 
+** [prepared statement] object.
+** back to its initial state, ready to be re-executed.
+** Any SQL statement variables that had values bound to them using
+** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
+** Use [sqlite3_clear_bindings()] to reset the bindings.
+**
+** {F11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
+**          back to the beginning of its program.
+**
+** {F11334} If the most recent call to [sqlite3_step(S)] for 
+**          [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
+**          or if [sqlite3_step(S)] has never before been called on S,
+**          then [sqlite3_reset(S)] returns [SQLITE_OK].
+**
+** {F11336} If the most recent call to [sqlite3_step(S)] for
+**          [prepared statement] S indicated an error, then
+**          [sqlite3_reset(S)] returns an appropriate [error code].
+**
+** {F11338} The [sqlite3_reset(S)] interface does not change the values
+**          of any [sqlite3_bind_blob|bindings] on [prepared statement] S.
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Create Or Redefine SQL Functions {F16100}
+** KEYWORDS: {function creation routines} 
+**
+** These two functions (collectively known as
+** "function creation routines") are used to add SQL functions or aggregates
+** or to redefine the behavior of existing SQL functions or aggregates.  The
+** difference only between the two is that the second parameter, the
+** name of the (scalar) function or aggregate, is encoded in UTF-8 for
+** sqlite3_create_function() and UTF-16 for sqlite3_create_function16().
+**
+** The first parameter is the [database connection] to which the SQL
+** function is to be added.  If a single
+** program uses more than one [database connection] internally, then SQL
+** functions must be added individually to each [database connection].
+**
+** The second parameter is the name of the SQL function to be created
+** or redefined.
+** The length of the name is limited to 255 bytes, exclusive of the 
+** zero-terminator.  Note that the name length limit is in bytes, not
+** characters.  Any attempt to create a function with a longer name
+** will result in an SQLITE_ERROR error.
+**
+** The third parameter is the number of arguments that the SQL function or
+** aggregate takes. If this parameter is negative, then the SQL function or
+** aggregate may take any number of arguments.
+**
+** The fourth parameter, eTextRep, specifies what 
+** [SQLITE_UTF8 | text encoding] this SQL function prefers for
+** its parameters.  Any SQL function implementation should be able to work
+** work with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
+** more efficient with one encoding than another.  It is allowed to
+** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
+** times with the same function but with different values of eTextRep.
+** When multiple implementations of the same function are available, SQLite
+** will pick the one that involves the least amount of data conversion.
+** If there is only a single implementation which does not care what
+** text encoding is used, then the fourth argument should be
+** [SQLITE_ANY].
+**
+** The fifth parameter is an arbitrary pointer.  The implementation
+** of the function can gain access to this pointer using
+** [sqlite3_user_data()].
+**
+** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
+** pointers to C-language functions that implement the SQL
+** function or aggregate. A scalar SQL function requires an implementation of
+** the xFunc callback only, NULL pointers should be passed as the xStep
+** and xFinal parameters. An aggregate SQL function requires an implementation
+** of xStep and xFinal and NULL should be passed for xFunc. To delete an
+** existing SQL function or aggregate, pass NULL for all three function
+** callback.
+**
+** It is permitted to register multiple implementations of the same
+** functions with the same name but with either differing numbers of
+** arguments or differing perferred text encodings.  SQLite will use
+** the implementation most closely matches the way in which the
+** SQL function is used.
+**
+** INVARIANTS:
+**
+** {F16103} The [sqlite3_create_function16()] interface behaves exactly
+**          like [sqlite3_create_function()] in every way except that it
+**          interprets the zFunctionName argument as
+**          zero-terminated UTF-16 native byte order instead of as a
+**          zero-terminated UTF-8.
+**
+** {F16106} A successful invocation of
+**          the [sqlite3_create_function(D,X,N,E,...)] interface registers
+**          or replaces callback functions in [database connection] D
+**          used to implement the SQL function named X with N parameters
+**          and having a perferred text encoding of E.
+**
+** {F16109} A successful call to [sqlite3_create_function(D,X,N,E,P,F,S,L)]
+**          replaces the P, F, S, and L values from any prior calls with
+**          the same D, X, N, and E values.
+**
+** {F16112} The [sqlite3_create_function(D,X,...)] interface fails with
+**          a return code of [SQLITE_ERROR] if the SQL function name X is
+**          longer than 255 bytes exclusive of the zero terminator.
+**
+** {F16118} Either F must be NULL and S and L are non-NULL or else F
+**          is non-NULL and S and L are NULL, otherwise
+**          [sqlite3_create_function(D,X,N,E,P,F,S,L)] returns [SQLITE_ERROR].
+**
+** {F16121} The [sqlite3_create_function(D,...)] interface fails with an
+**          error code of [SQLITE_BUSY] if there exist [prepared statements]
+**          associated with the [database connection] D.
+**
+** {F16124} The [sqlite3_create_function(D,X,N,...)] interface fails with an
+**          error code of [SQLITE_ERROR] if parameter N (specifying the number
+**          of arguments to the SQL function being registered) is less
+**          than -1 or greater than 127.
+**
+** {F16127} When N is non-negative, the [sqlite3_create_function(D,X,N,...)]
+**          interface causes callbacks to be invoked for the SQL function
+**          named X when the number of arguments to the SQL function is
+**          exactly N.
+**
+** {F16130} When N is -1, the [sqlite3_create_function(D,X,N,...)]
+**          interface causes callbacks to be invoked for the SQL function
+**          named X with any number of arguments.
+**
+** {F16133} When calls to [sqlite3_create_function(D,X,N,...)]
+**          specify multiple implementations of the same function X
+**          and when one implementation has N>=0 and the other has N=(-1)
+**          the implementation with a non-zero N is preferred.
+**
+** {F16136} When calls to [sqlite3_create_function(D,X,N,E,...)]
+**          specify multiple implementations of the same function X with
+**          the same number of arguments N but with different
+**          encodings E, then the implementation where E matches the
+**          database encoding is preferred.
+**
+** {F16139} For an aggregate SQL function created using
+**          [sqlite3_create_function(D,X,N,E,P,0,S,L)] the finializer
+**          function L will always be invoked exactly once if the
+**          step function S is called one or more times.
+**
+** {F16142} When SQLite invokes either the xFunc or xStep function of
+**          an application-defined SQL function or aggregate created
+**          by [sqlite3_create_function()] or [sqlite3_create_function16()],
+**          then the array of [sqlite3_value] objects passed as the
+**          third parameter are always [protected sqlite3_value] objects.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+
+/*
+** CAPI3REF: Text Encodings {F10267}
+**
+** These constant define integer codes that represent the various
+** text encodings supported by SQLite.
+*/
+#define SQLITE_UTF8           1
+#define SQLITE_UTF16LE        2
+#define SQLITE_UTF16BE        3
+#define SQLITE_UTF16          4    /* Use native byte order */
+#define SQLITE_ANY            5    /* sqlite3_create_function only */
+#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
+
+/*
+** CAPI3REF: Obsolete Functions
+**
+** These functions are all now obsolete.  In order to maintain
+** backwards compatibility with older code, we continue to support
+** these functions.  However, new development projects should avoid
+** the use of these functions.  To help encourage people to avoid
+** using these functions, we are not going to tell you want they do.
+*/
+SQLITE_API int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API int sqlite3_global_recover(void);
+SQLITE_API void sqlite3_thread_cleanup(void);
+SQLITE_API int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
+
+/*
+** CAPI3REF: Obtaining SQL Function Parameter Values {F15100}
+**
+** The C-language implementation of SQL functions and aggregates uses
+** this set of interface routines to access the parameter values on
+** the function or aggregate.
+**
+** The xFunc (for scalar functions) or xStep (for aggregates) parameters
+** to [sqlite3_create_function()] and [sqlite3_create_function16()]
+** define callbacks that implement the SQL functions and aggregates.
+** The 4th parameter to these callbacks is an array of pointers to
+** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
+** each parameter to the SQL function.  These routines are used to
+** extract values from the [sqlite3_value] objects.
+**
+** These routines work only with [protected sqlite3_value] objects.
+** Any attempt to use these routines on an [unprotected sqlite3_value]
+** object results in undefined behavior.
+**
+** These routines work just like the corresponding 
+** [sqlite3_column_blob | sqlite3_column_* routines] except that 
+** these routines take a single [protected sqlite3_value] object pointer
+** instead of an [sqlite3_stmt*] pointer and an integer column number.
+**
+** The sqlite3_value_text16() interface extracts a UTF16 string
+** in the native byte-order of the host machine.  The
+** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+** extract UTF16 strings as big-endian and little-endian respectively.
+**
+** The sqlite3_value_numeric_type() interface attempts to apply
+** numeric affinity to the value.  This means that an attempt is
+** made to convert the value to an integer or floating point.  If
+** such a conversion is possible without loss of information (in other
+** words if the value is a string that looks like a number)
+** then the conversion is done.  Otherwise no conversion occurs.  The 
+** [SQLITE_INTEGER | datatype] after conversion is returned.
+**
+** Please pay particular attention to the fact that the pointer that
+** is returned from [sqlite3_value_blob()], [sqlite3_value_text()], or
+** [sqlite3_value_text16()] can be invalidated by a subsequent call to
+** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
+** or [sqlite3_value_text16()].  
+**
+** These routines must be called from the same thread as
+** the SQL function that supplied the [sqlite3_value*] parameters.
+**
+**
+** INVARIANTS:
+**
+** {F15103} The [sqlite3_value_blob(V)] interface converts the
+**          [protected sqlite3_value] object V into a blob and then returns a
+**          pointer to the converted value.
+**
+** {F15106} The [sqlite3_value_bytes(V)] interface returns the
+**          number of bytes in the blob or string (exclusive of the
+**          zero terminator on the string) that was returned by the
+**          most recent call to [sqlite3_value_blob(V)] or
+**          [sqlite3_value_text(V)].
+**
+** {F15109} The [sqlite3_value_bytes16(V)] interface returns the
+**          number of bytes in the string (exclusive of the
+**          zero terminator on the string) that was returned by the
+**          most recent call to [sqlite3_value_text16(V)],
+**          [sqlite3_value_text16be(V)], or [sqlite3_value_text16le(V)].
+**
+** {F15112} The [sqlite3_value_double(V)] interface converts the
+**          [protected sqlite3_value] object V into a floating point value and
+**          returns a copy of that value.
+**
+** {F15115} The [sqlite3_value_int(V)] interface converts the
+**          [protected sqlite3_value] object V into a 64-bit signed integer and
+**          returns the lower 32 bits of that integer.
+**
+** {F15118} The [sqlite3_value_int64(V)] interface converts the
+**          [protected sqlite3_value] object V into a 64-bit signed integer and
+**          returns a copy of that integer.
+**
+** {F15121} The [sqlite3_value_text(V)] interface converts the
+**          [protected sqlite3_value] object V into a zero-terminated UTF-8 
+**          string and returns a pointer to that string.
+**
+** {F15124} The [sqlite3_value_text16(V)] interface converts the
+**          [protected sqlite3_value] object V into a zero-terminated 2-byte
+**          aligned UTF-16 native byte order
+**          string and returns a pointer to that string.
+**
+** {F15127} The [sqlite3_value_text16be(V)] interface converts the
+**          [protected sqlite3_value] object V into a zero-terminated 2-byte
+**          aligned UTF-16 big-endian
+**          string and returns a pointer to that string.
+**
+** {F15130} The [sqlite3_value_text16le(V)] interface converts the
+**          [protected sqlite3_value] object V into a zero-terminated 2-byte
+**          aligned UTF-16 little-endian
+**          string and returns a pointer to that string.
+**
+** {F15133} The [sqlite3_value_type(V)] interface returns
+**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
+**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
+**          the [sqlite3_value] object V.
+**
+** {F15136} The [sqlite3_value_numeric_type(V)] interface converts
+**          the [protected sqlite3_value] object V into either an integer or
+**          a floating point value if it can do so without loss of
+**          information, and returns one of [SQLITE_NULL],
+**          [SQLITE_INTEGER], [SQLITE_FLOAT], [SQLITE_TEXT], or
+**          [SQLITE_BLOB] as appropriate for
+**          the [protected sqlite3_value] object V after the conversion attempt.
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
+
+/*
+** CAPI3REF: Obtain Aggregate Function Context {F16210}
+**
+** The implementation of aggregate SQL functions use this routine to allocate
+** a structure for storing their state.  
+** The first time the sqlite3_aggregate_context() routine is
+** is called for a particular aggregate, SQLite allocates nBytes of memory
+** zeros that memory, and returns a pointer to it.
+** On second and subsequent calls to sqlite3_aggregate_context()
+** for the same aggregate function index, the same buffer is returned.
+** The implementation
+** of the aggregate can use the returned buffer to accumulate data.
+**
+** SQLite automatically frees the allocated buffer when the aggregate
+** query concludes.
+**
+** The first parameter should be a copy of the 
+** [sqlite3_context | SQL function context] that is the first
+** parameter to the callback routine that implements the aggregate
+** function.
+**
+** This routine must be called from the same thread in which
+** the aggregate SQL function is running.
+**
+** INVARIANTS:
+**
+** {F16211} The first invocation of [sqlite3_aggregate_context(C,N)] for
+**          a particular instance of an aggregate function (for a particular
+**          context C) causes SQLite to allocation N bytes of memory,
+**          zero that memory, and return a pointer to the allocationed
+**          memory.
+**
+** {F16213} If a memory allocation error occurs during
+**          [sqlite3_aggregate_context(C,N)] then the function returns 0.
+**
+** {F16215} Second and subsequent invocations of
+**          [sqlite3_aggregate_context(C,N)] for the same context pointer C
+**          ignore the N parameter and return a pointer to the same
+**          block of memory returned by the first invocation.
+**
+** {F16217} The memory allocated by [sqlite3_aggregate_context(C,N)] is
+**          automatically freed on the next call to [sqlite3_reset()]
+**          or [sqlite3_finalize()] for the [prepared statement] containing
+**          the aggregate function associated with context C.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+
+/*
+** CAPI3REF: User Data For Functions {F16240}
+**
+** The sqlite3_user_data() interface returns a copy of
+** the pointer that was the pUserData parameter (the 5th parameter)
+** of the the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function. {END}
+**
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+**
+** INVARIANTS:
+**
+** {F16243} The [sqlite3_user_data(C)] interface returns a copy of the
+**          P pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
+**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
+**          registered the SQL function associated with 
+**          [sqlite3_context] C.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions {F16250}
+**
+** The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+**
+** INVARIANTS:
+**
+** {F16253} The [sqlite3_context_db_handle(C)] interface returns a copy of the
+**          D pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
+**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
+**          registered the SQL function associated with 
+**          [sqlite3_context] C.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data {F16270}
+**
+** The following two functions may be used by scalar SQL functions to
+** associate meta-data with argument values. If the same value is passed to
+** multiple invocations of the same SQL function during query execution, under
+** some circumstances the associated meta-data may be preserved. This may
+** be used, for example, to add a regular-expression matching scalar
+** function. The compiled version of the regular expression is stored as
+** meta-data associated with the SQL value passed as the regular expression
+** pattern.  The compiled regular expression can be reused on multiple
+** invocations of the same function so that the original pattern string
+** does not need to be recompiled on each invocation.
+**
+** The sqlite3_get_auxdata() interface returns a pointer to the meta-data
+** associated by the sqlite3_set_auxdata() function with the Nth argument
+** value to the application-defined function.
+** If no meta-data has been ever been set for the Nth
+** argument of the function, or if the cooresponding function parameter
+** has changed since the meta-data was set, then sqlite3_get_auxdata()
+** returns a NULL pointer.
+**
+** The sqlite3_set_auxdata() interface saves the meta-data
+** pointed to by its 3rd parameter as the meta-data for the N-th
+** argument of the application-defined function.  Subsequent
+** calls to sqlite3_get_auxdata() might return this data, if it has
+** not been destroyed. 
+** If it is not NULL, SQLite will invoke the destructor 
+** function given by the 4th parameter to sqlite3_set_auxdata() on
+** the meta-data when the corresponding function parameter changes
+** or when the SQL statement completes, whichever comes first.
+**
+** SQLite is free to call the destructor and drop meta-data on
+** any parameter of any function at any time.  The only guarantee
+** is that the destructor will be called before the metadata is
+** dropped.
+**
+** In practice, meta-data is preserved between function calls for
+** expressions that are constant at compile time. This includes literal
+** values and SQL variables.
+**
+** These routines must be called from the same thread in which
+** the SQL function is running.
+**
+** INVARIANTS:
+**
+** {F16272} The [sqlite3_get_auxdata(C,N)] interface returns a pointer
+**          to metadata associated with the Nth parameter of the SQL function
+**          whose context is C, or NULL if there is no metadata associated
+**          with that parameter.
+**
+** {F16274} The [sqlite3_set_auxdata(C,N,P,D)] interface assigns a metadata
+**          pointer P to the Nth parameter of the SQL function with context
+**          C.
+**
+** {F16276} SQLite will invoke the destructor D with a single argument
+**          which is the metadata pointer P following a call to
+**          [sqlite3_set_auxdata(C,N,P,D)] when SQLite ceases to hold
+**          the metadata.
+**
+** {F16277} SQLite ceases to hold metadata for an SQL function parameter
+**          when the value of that parameter changes.
+**
+** {F16278} When [sqlite3_set_auxdata(C,N,P,D)] is invoked, the destructor
+**          is called for any prior metadata associated with the same function
+**          context C and parameter N.
+**
+** {F16279} SQLite will call destructors for any metadata it is holding
+**          in a particular [prepared statement] S when either
+**          [sqlite3_reset(S)] or [sqlite3_finalize(S)] is called.
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+
+
+/*
+** CAPI3REF: Constants Defining Special Destructor Behavior {F10280}
+**
+** These are special value for the destructor that is passed in as the
+** final argument to routines like [sqlite3_result_blob()].  If the destructor
+** argument is SQLITE_STATIC, it means that the content pointer is constant
+** and will never change.  It does not need to be destroyed.  The 
+** SQLITE_TRANSIENT value means that the content will likely change in
+** the near future and that SQLite should make its own private copy of
+** the content before returning.
+**
+** The typedef is necessary to work around problems in certain
+** C++ compilers.  See ticket #2191.
+*/
+typedef void (*sqlite3_destructor_type)(void*);
+#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
+#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
+
+/*
+** CAPI3REF: Setting The Result Of An SQL Function {F16400}
+**
+** These routines are used by the xFunc or xFinal callbacks that
+** implement SQL functions and aggregates.  See
+** [sqlite3_create_function()] and [sqlite3_create_function16()]
+** for additional information.
+**
+** These functions work very much like the 
+** [sqlite3_bind_blob | sqlite3_bind_*] family of functions used
+** to bind values to host parameters in prepared statements.
+** Refer to the
+** [sqlite3_bind_blob | sqlite3_bind_* documentation] for
+** additional information.
+**
+** The sqlite3_result_blob() interface sets the result from
+** an application defined function to be the BLOB whose content is pointed
+** to by the second parameter and which is N bytes long where N is the
+** third parameter. 
+** The sqlite3_result_zeroblob() inerfaces set the result of
+** the application defined function to be a BLOB containing all zero
+** bytes and N bytes in size, where N is the value of the 2nd parameter.
+**
+** The sqlite3_result_double() interface sets the result from
+** an application defined function to be a floating point value specified
+** by its 2nd argument.
+**
+** The sqlite3_result_error() and sqlite3_result_error16() functions
+** cause the implemented SQL function to throw an exception.
+** SQLite uses the string pointed to by the
+** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
+** as the text of an error message.  SQLite interprets the error
+** message string from sqlite3_result_error() as UTF8. SQLite
+** interprets the string from sqlite3_result_error16() as UTF16 in native
+** byte order.  If the third parameter to sqlite3_result_error()
+** or sqlite3_result_error16() is negative then SQLite takes as the error
+** message all text up through the first zero character.
+** If the third parameter to sqlite3_result_error() or
+** sqlite3_result_error16() is non-negative then SQLite takes that many
+** bytes (not characters) from the 2nd parameter as the error message.
+** The sqlite3_result_error() and sqlite3_result_error16()
+** routines make a copy private copy of the error message text before
+** they return.  Hence, the calling function can deallocate or
+** modify the text after they return without harm.
+** The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  By default,
+** the error code is SQLITE_ERROR.  A subsequent call to sqlite3_result_error()
+** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
+**
+** The sqlite3_result_toobig() interface causes SQLite
+** to throw an error indicating that a string or BLOB is to long
+** to represent.  The sqlite3_result_nomem() interface
+** causes SQLite to throw an exception indicating that the a
+** memory allocation failed.
+**
+** The sqlite3_result_int() interface sets the return value
+** of the application-defined function to be the 32-bit signed integer
+** value given in the 2nd argument.
+** The sqlite3_result_int64() interface sets the return value
+** of the application-defined function to be the 64-bit signed integer
+** value given in the 2nd argument.
+**
+** The sqlite3_result_null() interface sets the return value
+** of the application-defined function to be NULL.
+**
+** The sqlite3_result_text(), sqlite3_result_text16(), 
+** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
+** set the return value of the application-defined function to be
+** a text string which is represented as UTF-8, UTF-16 native byte order,
+** UTF-16 little endian, or UTF-16 big endian, respectively.
+** SQLite takes the text result from the application from
+** the 2nd parameter of the sqlite3_result_text* interfaces.
+** If the 3rd parameter to the sqlite3_result_text* interfaces
+** is negative, then SQLite takes result text from the 2nd parameter 
+** through the first zero character.
+** If the 3rd parameter to the sqlite3_result_text* interfaces
+** is non-negative, then as many bytes (not characters) of the text
+** pointed to by the 2nd parameter are taken as the application-defined
+** function result.
+** If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
+** function as the destructor on the text or blob result when it has
+** finished using that result.
+** If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_STATIC, then
+** SQLite assumes that the text or blob result is constant space and
+** does not copy the space or call a destructor when it has
+** finished using that result.
+** If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
+** then SQLite makes a copy of the result into space obtained from
+** from [sqlite3_malloc()] before it returns.
+**
+** The sqlite3_result_value() interface sets the result of
+** the application-defined function to be a copy the
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  The
+** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
+** so that [sqlite3_value] specified in the parameter may change or
+** be deallocated after sqlite3_result_value() returns without harm.
+** A [protected sqlite3_value] object may always be used where an
+** [unprotected sqlite3_value] object is required, so either
+** kind of [sqlite3_value] object can be used with this interface.
+**
+** If these routines are called from within the different thread 
+** than the one containing the application-defined function that recieved
+** the [sqlite3_context] pointer, the results are undefined.
+**
+** INVARIANTS:
+**
+** {F16403} The default return value from any SQL function is NULL.
+**
+** {F16406} The [sqlite3_result_blob(C,V,N,D)] interface changes the
+**          return value of function C to be a blob that is N bytes
+**          in length and with content pointed to by V.
+**
+** {F16409} The [sqlite3_result_double(C,V)] interface changes the
+**          return value of function C to be the floating point value V.
+**
+** {F16412} The [sqlite3_result_error(C,V,N)] interface changes the return
+**          value of function C to be an exception with error code
+**          [SQLITE_ERROR] and a UTF8 error message copied from V up to the
+**          first zero byte or until N bytes are read if N is positive.
+**
+** {F16415} The [sqlite3_result_error16(C,V,N)] interface changes the return
+**          value of function C to be an exception with error code
+**          [SQLITE_ERROR] and a UTF16 native byte order error message
+**          copied from V up to the first zero terminator or until N bytes
+**          are read if N is positive.
+**
+** {F16418} The [sqlite3_result_error_toobig(C)] interface changes the return
+**          value of the function C to be an exception with error code
+**          [SQLITE_TOOBIG] and an appropriate error message.
+**
+** {F16421} The [sqlite3_result_error_nomem(C)] interface changes the return
+**          value of the function C to be an exception with error code
+**          [SQLITE_NOMEM] and an appropriate error message.
+**
+** {F16424} The [sqlite3_result_error_code(C,E)] interface changes the return
+**          value of the function C to be an exception with error code E.
+**          The error message text is unchanged.
+**
+** {F16427} The [sqlite3_result_int(C,V)] interface changes the
+**          return value of function C to be the 32-bit integer value V.
+**
+** {F16430} The [sqlite3_result_int64(C,V)] interface changes the
+**          return value of function C to be the 64-bit integer value V.
+**
+** {F16433} The [sqlite3_result_null(C)] interface changes the
+**          return value of function C to be NULL.
+**
+** {F16436} The [sqlite3_result_text(C,V,N,D)] interface changes the
+**          return value of function C to be the UTF8 string
+**          V up to the first zero if N is negative
+**          or the first N bytes of V if N is non-negative.
+**
+** {F16439} The [sqlite3_result_text16(C,V,N,D)] interface changes the
+**          return value of function C to be the UTF16 native byte order
+**          string V up to the first zero if N is
+**          negative or the first N bytes of V if N is non-negative.
+**
+** {F16442} The [sqlite3_result_text16be(C,V,N,D)] interface changes the
+**          return value of function C to be the UTF16 big-endian
+**          string V up to the first zero if N is
+**          is negative or the first N bytes or V if N is non-negative.
+**
+** {F16445} The [sqlite3_result_text16le(C,V,N,D)] interface changes the
+**          return value of function C to be the UTF16 little-endian
+**          string V up to the first zero if N is
+**          negative or the first N bytes of V if N is non-negative.
+**
+** {F16448} The [sqlite3_result_value(C,V)] interface changes the
+**          return value of function C to be [unprotected sqlite3_value]
+**          object V.
+**
+** {F16451} The [sqlite3_result_zeroblob(C,N)] interface changes the
+**          return value of function C to be an N-byte blob of all zeros.
+**
+** {F16454} The [sqlite3_result_error()] and [sqlite3_result_error16()]
+**          interfaces make a copy of their error message strings before
+**          returning.
+**
+** {F16457} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
+**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
+**          [sqlite3_result_text16be(C,V,N,D)], or
+**          [sqlite3_result_text16le(C,V,N,D)] is the constant [SQLITE_STATIC]
+**          then no destructor is ever called on the pointer V and SQLite
+**          assumes that V is immutable.
+**
+** {F16460} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
+**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
+**          [sqlite3_result_text16be(C,V,N,D)], or
+**          [sqlite3_result_text16le(C,V,N,D)] is the constant
+**          [SQLITE_TRANSIENT] then the interfaces makes a copy of the
+**          content of V and retains the copy.
+**
+** {F16463} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
+**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
+**          [sqlite3_result_text16be(C,V,N,D)], or
+**          [sqlite3_result_text16le(C,V,N,D)] is some value other than
+**          the constants [SQLITE_STATIC] and [SQLITE_TRANSIENT] then 
+**          SQLite will invoke the destructor D with V as its only argument
+**          when it has finished with the V value.
+*/
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
+
+/*
+** CAPI3REF: Define New Collating Sequences {F16600}
+**
+** These functions are used to add new collation sequences to the
+** [sqlite3*] handle specified as the first argument. 
+**
+** The name of the new collation sequence is specified as a UTF-8 string
+** for sqlite3_create_collation() and sqlite3_create_collation_v2()
+** and a UTF-16 string for sqlite3_create_collation16(). In all cases
+** the name is passed as the second function argument.
+**
+** The third argument may be one of the constants [SQLITE_UTF8],
+** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied
+** routine expects to be passed pointers to strings encoded using UTF-8,
+** UTF-16 little-endian or UTF-16 big-endian respectively. The
+** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that
+** the routine expects pointers to 16-bit word aligned strings
+** of UTF16 in the native byte order of the host computer.
+**
+** A pointer to the user supplied routine must be passed as the fifth
+** argument.  If it is NULL, this is the same as deleting the collation
+** sequence (so that SQLite cannot call it anymore).
+** Each time the application
+** supplied function is invoked, it is passed a copy of the void* passed as
+** the fourth argument to sqlite3_create_collation() or
+** sqlite3_create_collation16() as its first parameter.
+**
+** The remaining arguments to the application-supplied routine are two strings,
+** each represented by a (length, data) pair and encoded in the encoding
+** that was passed as the third argument when the collation sequence was
+** registered. {END} The application defined collation routine should
+** return negative, zero or positive if
+** the first string is less than, equal to, or greater than the second
+** string. i.e. (STRING1 - STRING2).
+**
+** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** excapt that it takes an extra argument which is a destructor for
+** the collation.  The destructor is called when the collation is
+** destroyed and is passed a copy of the fourth parameter void* pointer
+** of the sqlite3_create_collation_v2().
+** Collations are destroyed when
+** they are overridden by later calls to the collation creation functions
+** or when the [sqlite3*] database handle is closed using [sqlite3_close()].
+**
+** INVARIANTS:
+**
+** {F16603} A successful call to the
+**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] interface
+**          registers function F as the comparison function used to
+**          implement collation X on [database connection] B for
+**          databases having encoding E.
+**
+** {F16604} SQLite understands the X parameter to
+**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] as a zero-terminated
+**          UTF-8 string in which case is ignored for ASCII characters and
+**          is significant for non-ASCII characters.
+**
+** {F16606} Successive calls to [sqlite3_create_collation_v2(B,X,E,P,F,D)]
+**          with the same values for B, X, and E, override prior values
+**          of P, F, and D.
+**
+** {F16609} The destructor D in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
+**          is not NULL then it is called with argument P when the
+**          collating function is dropped by SQLite.
+**
+** {F16612} A collating function is dropped when it is overloaded.
+**
+** {F16615} A collating function is dropped when the database connection
+**          is closed using [sqlite3_close()].
+**
+** {F16618} The pointer P in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
+**          is passed through as the first parameter to the comparison
+**          function F for all subsequent invocations of F.
+**
+** {F16621} A call to [sqlite3_create_collation(B,X,E,P,F)] is exactly
+**          the same as a call to [sqlite3_create_collation_v2()] with
+**          the same parameters and a NULL destructor.
+**
+** {F16624} Following a [sqlite3_create_collation_v2(B,X,E,P,F,D)],
+**          SQLite uses the comparison function F for all text comparison
+**          operations on [database connection] B on text values that
+**          use the collating sequence name X.
+**
+** {F16627} The [sqlite3_create_collation16(B,X,E,P,F)] works the same
+**          as [sqlite3_create_collation(B,X,E,P,F)] except that the
+**          collation name X is understood as UTF-16 in native byte order
+**          instead of UTF-8.
+**
+** {F16630} When multiple comparison functions are available for the same
+**          collating sequence, SQLite chooses the one whose text encoding
+**          requires the least amount of conversion from the default
+**          text encoding of the database.
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3*, 
+  const char *zName, 
+  int eTextRep, 
+  void*,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3*, 
+  const char *zName, 
+  int eTextRep, 
+  void*,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3*, 
+  const char *zName, 
+  int eTextRep, 
+  void*,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+
+/*
+** CAPI3REF: Collation Needed Callbacks {F16700}
+**
+** To avoid having to register all collation sequences before a database
+** can be used, a single callback function may be registered with the
+** database handle to be called whenever an undefined collation sequence is
+** required.
+**
+** If the function is registered using the sqlite3_collation_needed() API,
+** then it is passed the names of undefined collation sequences as strings
+** encoded in UTF-8. {F16703} If sqlite3_collation_needed16() is used, the names
+** are passed as UTF-16 in machine native byte order. A call to either
+** function replaces any existing callback.
+**
+** When the callback is invoked, the first argument passed is a copy
+** of the second argument to sqlite3_collation_needed() or
+** sqlite3_collation_needed16().  The second argument is the database
+** handle.  The third argument is one of [SQLITE_UTF8],
+** [SQLITE_UTF16BE], or [SQLITE_UTF16LE], indicating the most
+** desirable form of the collation sequence function required.
+** The fourth parameter is the name of the
+** required collation sequence.
+**
+** The callback function should register the desired collation using
+** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
+** [sqlite3_create_collation_v2()].
+**
+** INVARIANTS:
+**
+** {F16702} A successful call to [sqlite3_collation_needed(D,P,F)]
+**          or [sqlite3_collation_needed16(D,P,F)] causes
+**          the [database connection] D to invoke callback F with first
+**          parameter P whenever it needs a comparison function for a
+**          collating sequence that it does not know about.
+**
+** {F16704} Each successful call to [sqlite3_collation_needed()] or
+**          [sqlite3_collation_needed16()] overrides the callback registered
+**          on the same [database connection] by prior calls to either
+**          interface.
+**
+** {F16706} The name of the requested collating function passed in the
+**          4th parameter to the callback is in UTF-8 if the callback
+**          was registered using [sqlite3_collation_needed()] and
+**          is in UTF-16 native byte order if the callback was
+**          registered using [sqlite3_collation_needed16()].
+**
+** 
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3*, 
+  void*, 
+  void(*)(void*,sqlite3*,int eTextRep,const char*)
+);
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3*, 
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const void*)
+);
+
+/*
+** Specify the key for an encrypted database.  This routine should be
+** called right after sqlite3_open().
+**
+** The code to implement this API is not available in the public release
+** of SQLite.
+*/
+SQLITE_API int sqlite3_key(
+  sqlite3 *db,                   /* Database to be rekeyed */
+  const void *pKey, int nKey     /* The key */
+);
+
+/*
+** Change the key on an open database.  If the current database is not
+** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
+** database is decrypted.
+**
+** The code to implement this API is not available in the public release
+** of SQLite.
+*/
+SQLITE_API int sqlite3_rekey(
+  sqlite3 *db,                   /* Database to be rekeyed */
+  const void *pKey, int nKey     /* The new key */
+);
+
+/*
+** CAPI3REF:  Suspend Execution For A Short Time {F10530}
+**
+** The sqlite3_sleep() function
+** causes the current thread to suspend execution
+** for at least a number of milliseconds specified in its parameter.
+**
+** If the operating system does not support sleep requests with 
+** millisecond time resolution, then the time will be rounded up to 
+** the nearest second. The number of milliseconds of sleep actually 
+** requested from the operating system is returned.
+**
+** SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.
+**
+** INVARIANTS:
+**
+** {F10533} The [sqlite3_sleep(M)] interface invokes the xSleep
+**          method of the default [sqlite3_vfs|VFS] in order to
+**          suspend execution of the current thread for at least
+**          M milliseconds.
+**
+** {F10536} The [sqlite3_sleep(M)] interface returns the number of
+**          milliseconds of sleep actually requested of the operating
+**          system, which might be larger than the parameter M.
+*/
+SQLITE_API int sqlite3_sleep(int);
+
+/*
+** CAPI3REF:  Name Of The Folder Holding Temporary Files {F10310}
+**
+** If this global variable is made to point to a string which is
+** the name of a folder (a.ka. directory), then all temporary files
+** created by SQLite will be placed in that directory.  If this variable
+** is NULL pointer, then SQLite does a search for an appropriate temporary
+** file directory.
+**
+** It is not safe to modify this variable once a database connection
+** has been opened.  It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been call and remain unchanged thereafter.
+*/
+SQLITE_API char *sqlite3_temp_directory;
+
+/*
+** CAPI3REF:  Test To See If The Database Is In Auto-Commit Mode {F12930}
+**
+** The sqlite3_get_autocommit() interfaces returns non-zero or
+** zero if the given database connection is or is not in autocommit mode,
+** respectively.   Autocommit mode is on
+** by default.  Autocommit mode is disabled by a [BEGIN] statement.
+** Autocommit mode is reenabled by a [COMMIT] or [ROLLBACK].
+**
+** If certain kinds of errors occur on a statement within a multi-statement
+** transactions (errors including [SQLITE_FULL], [SQLITE_IOERR], 
+** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
+** transaction might be rolled back automatically.  The only way to
+** find out if SQLite automatically rolled back the transaction after
+** an error is to use this function.
+**
+** INVARIANTS:
+**
+** {F12931} The [sqlite3_get_autocommit(D)] interface returns non-zero or
+**          zero if the [database connection] D is or is not in autocommit
+**          mode, respectively.
+**
+** {F12932} Autocommit mode is on by default.
+**
+** {F12933} Autocommit mode is disabled by a successful [BEGIN] statement.
+**
+** {F12934} Autocommit mode is enabled by a successful [COMMIT] or [ROLLBACK]
+**          statement.
+** 
+**
+** LIMITATIONS:
+***
+** {U12936} If another thread changes the autocommit status of the database
+**          connection while this routine is running, then the return value
+**          is undefined.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
+
+/*
+** CAPI3REF:  Find The Database Handle Of A Prepared Statement {F13120}
+**
+** The sqlite3_db_handle interface
+** returns the [sqlite3*] database handle to which a
+** [prepared statement] belongs.
+** The database handle returned by sqlite3_db_handle
+** is the same database handle that was
+** the first argument to the [sqlite3_prepare_v2()] or its variants
+** that was used to create the statement in the first place.
+**
+** INVARIANTS:
+**
+** {F13123} The [sqlite3_db_handle(S)] interface returns a pointer
+**          to the [database connection] associated with
+**          [prepared statement] S.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+
+
+/*
+** CAPI3REF: Commit And Rollback Notification Callbacks {F12950}
+**
+** The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is committed.
+** Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is committed.
+** Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** The pArg argument is passed through
+** to the callback.  If the callback on a commit hook function 
+** returns non-zero, then the commit is converted into a rollback.
+**
+** If another function was previously registered, its
+** pArg value is returned.  Otherwise NULL is returned.
+**
+** Registering a NULL function disables the callback.
+**
+** For the purposes of this API, a transaction is said to have been 
+** rolled back if an explicit "ROLLBACK" statement is executed, or
+** an error or constraint causes an implicit rollback to occur.
+** The rollback callback is not invoked if a transaction is
+** automatically rolled back because the database connection is closed.
+** The rollback callback is not invoked if a transaction is
+** rolled back because a commit callback returned non-zero.
+** <todo> Check on this </todo>
+**
+** These are experimental interfaces and are subject to change.
+**
+** INVARIANTS:
+**
+** {F12951} The [sqlite3_commit_hook(D,F,P)] interface registers the
+**          callback function F to be invoked with argument P whenever
+**          a transaction commits on [database connection] D.
+**
+** {F12952} The [sqlite3_commit_hook(D,F,P)] interface returns the P
+**          argument from the previous call with the same 
+**          [database connection ] D , or NULL on the first call
+**          for a particular [database connection] D.
+**
+** {F12953} Each call to [sqlite3_commit_hook()] overwrites the callback
+**          registered by prior calls.
+**
+** {F12954} If the F argument to [sqlite3_commit_hook(D,F,P)] is NULL
+**          then the commit hook callback is cancelled and no callback
+**          is invoked when a transaction commits.
+**
+** {F12955} If the commit callback returns non-zero then the commit is
+**          converted into a rollback.
+**
+** {F12961} The [sqlite3_rollback_hook(D,F,P)] interface registers the
+**          callback function F to be invoked with argument P whenever
+**          a transaction rolls back on [database connection] D.
+**
+** {F12962} The [sqlite3_rollback_hook(D,F,P)] interface returns the P
+**          argument from the previous call with the same 
+**          [database connection ] D , or NULL on the first call
+**          for a particular [database connection] D.
+**
+** {F12963} Each call to [sqlite3_rollback_hook()] overwrites the callback
+**          registered by prior calls.
+**
+** {F12964} If the F argument to [sqlite3_rollback_hook(D,F,P)] is NULL
+**          then the rollback hook callback is cancelled and no callback
+**          is invoked when a transaction rolls back.
+*/
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+
+/*
+** CAPI3REF: Data Change Notification Callbacks {F12970}
+**
+** The sqlite3_update_hook() interface
+** registers a callback function with the database connection identified by the 
+** first argument to be invoked whenever a row is updated, inserted or deleted.
+** Any callback set by a previous call to this function for the same 
+** database connection is overridden.
+**
+** The second argument is a pointer to the function to invoke when a 
+** row is updated, inserted or deleted. 
+** The first argument to the callback is
+** a copy of the third argument to sqlite3_update_hook().
+** The second callback 
+** argument is one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+** depending on the operation that caused the callback to be invoked.
+** The third and 
+** fourth arguments to the callback contain pointers to the database and 
+** table name containing the affected row.
+** The final callback parameter is 
+** the rowid of the row.
+** In the case of an update, this is the rowid after 
+** the update takes place.
+**
+** The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_master and sqlite_sequence).
+**
+** If another function was previously registered, its pArg value
+** is returned.  Otherwise NULL is returned.
+**
+** INVARIANTS:
+**
+** {F12971} The [sqlite3_update_hook(D,F,P)] interface causes callback
+**          function F to be invoked with first parameter P whenever
+**          a table row is modified, inserted, or deleted on
+**          [database connection] D.
+**
+** {F12973} The [sqlite3_update_hook(D,F,P)] interface returns the value
+**          of P for the previous call on the same [database connection] D,
+**          or NULL for the first call.
+**
+** {F12975} If the update hook callback F in [sqlite3_update_hook(D,F,P)]
+**          is NULL then the no update callbacks are made.
+**
+** {F12977} Each call to [sqlite3_update_hook(D,F,P)] overrides prior calls
+**          to the same interface on the same [database connection] D.
+**
+** {F12979} The update hook callback is not invoked when internal system
+**          tables such as sqlite_master and sqlite_sequence are modified.
+**
+** {F12981} The second parameter to the update callback 
+**          is one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+**          depending on the operation that caused the callback to be invoked.
+**
+** {F12983} The third and fourth arguments to the callback contain pointers
+**          to zero-terminated UTF-8 strings which are the names of the
+**          database and table that is being updated.
+
+** {F12985} The final callback parameter is the rowid of the row after
+**          the change occurs.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3*, 
+  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
+  void*
+);
+
+/*
+** CAPI3REF:  Enable Or Disable Shared Pager Cache {F10330}
+**
+** This routine enables or disables the sharing of the database cache
+** and schema data structures between connections to the same database.
+** Sharing is enabled if the argument is true and disabled if the argument
+** is false.
+**
+** Cache sharing is enabled and disabled
+** for an entire process. {END} This is a change as of SQLite version 3.5.0.
+** In prior versions of SQLite, sharing was
+** enabled or disabled for each thread separately.
+**
+** The cache sharing mode set by this interface effects all subsequent
+** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
+** Existing database connections continue use the sharing mode
+** that was in effect at the time they were opened.
+**
+** Virtual tables cannot be used with a shared cache.   When shared
+** cache is enabled, the [sqlite3_create_module()] API used to register
+** virtual tables will always return an error.
+**
+** This routine returns [SQLITE_OK] if shared cache was
+** enabled or disabled successfully.  An [error code]
+** is returned otherwise.
+**
+** Shared cache is disabled by default. But this might change in
+** future releases of SQLite.  Applications that care about shared
+** cache setting should set it explicitly.
+**
+** INVARIANTS:
+** 
+** {F10331} A successful invocation of [sqlite3_enable_shared_cache(B)]
+**          will enable or disable shared cache mode for any subsequently
+**          created [database connection] in the same process.
+**
+** {F10336} When shared cache is enabled, the [sqlite3_create_module()]
+**          interface will always return an error.
+**
+** {F10337} The [sqlite3_enable_shared_cache(B)] interface returns
+**          [SQLITE_OK] if shared cache was enabled or disabled successfully.
+**
+** {F10339} Shared cache is disabled by default.
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int);
+
+/*
+** CAPI3REF:  Attempt To Free Heap Memory {F17340}
+**
+** The sqlite3_release_memory() interface attempts to
+** free N bytes of heap memory by deallocating non-essential memory
+** allocations held by the database labrary. {END}  Memory used
+** to cache database pages to improve performance is an example of
+** non-essential memory.  Sqlite3_release_memory() returns
+** the number of bytes actually freed, which might be more or less
+** than the amount requested.
+**
+** INVARIANTS:
+**
+** {F17341} The [sqlite3_release_memory(N)] interface attempts to
+**          free N bytes of heap memory by deallocating non-essential
+**          memory allocations held by the database labrary.
+**
+** {F16342} The [sqlite3_release_memory(N)] returns the number
+**          of bytes actually freed, which might be more or less
+**          than the amount requested.
+*/
+SQLITE_API int sqlite3_release_memory(int);
+
+/*
+** CAPI3REF:  Impose A Limit On Heap Size {F17350}
+**
+** The sqlite3_soft_heap_limit() interface
+** places a "soft" limit on the amount of heap memory that may be allocated
+** by SQLite. If an internal allocation is requested 
+** that would exceed the soft heap limit, [sqlite3_release_memory()] is
+** invoked one or more times to free up some space before the allocation
+** is made.
+**
+** The limit is called "soft", because if
+** [sqlite3_release_memory()] cannot
+** free sufficient memory to prevent the limit from being exceeded,
+** the memory is allocated anyway and the current operation proceeds.
+**
+** A negative or zero value for N means that there is no soft heap limit and
+** [sqlite3_release_memory()] will only be called when memory is exhausted.
+** The default value for the soft heap limit is zero.
+**
+** SQLite makes a best effort to honor the soft heap limit.  
+** But if the soft heap limit cannot honored, execution will
+** continue without error or notification.  This is why the limit is 
+** called a "soft" limit.  It is advisory only.
+**
+** Prior to SQLite version 3.5.0, this routine only constrained the memory
+** allocated by a single thread - the same thread in which this routine
+** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
+** applied to all threads. The value specified for the soft heap limit
+** is an upper bound on the total memory allocation for all threads. In
+** version 3.5.0 there is no mechanism for limiting the heap usage for
+** individual threads.
+**
+** INVARIANTS:
+**
+** {F16351} The [sqlite3_soft_heap_limit(N)] interface places a soft limit
+**          of N bytes on the amount of heap memory that may be allocated
+**          using [sqlite3_malloc()] or [sqlite3_realloc()] at any point
+**          in time.
+**
+** {F16352} If a call to [sqlite3_malloc()] or [sqlite3_realloc()] would
+**          cause the total amount of allocated memory to exceed the
+**          soft heap limit, then [sqlite3_release_memory()] is invoked
+**          in an attempt to reduce the memory usage prior to proceeding
+**          with the memory allocation attempt.
+**
+** {F16353} Calls to [sqlite3_malloc()] or [sqlite3_realloc()] that trigger
+**          attempts to reduce memory usage through the soft heap limit
+**          mechanism continue even if the attempt to reduce memory
+**          usage is unsuccessful.
+**
+** {F16354} A negative or zero value for N in a call to
+**          [sqlite3_soft_heap_limit(N)] means that there is no soft
+**          heap limit and [sqlite3_release_memory()] will only be
+**          called when memory is completely exhausted.
+**
+** {F16355} The default value for the soft heap limit is zero.
+**
+** {F16358} Each call to [sqlite3_soft_heap_limit(N)] overrides the
+**          values set by all prior calls.
+*/
+SQLITE_API void sqlite3_soft_heap_limit(int);
+
+/*
+** CAPI3REF:  Extract Metadata About A Column Of A Table {F12850}
+**
+** This routine
+** returns meta-data about a specific column of a specific database
+** table accessible using the connection handle passed as the first function 
+** argument.
+**
+** The column is identified by the second, third and fourth parameters to 
+** this function. The second parameter is either the name of the database
+** (i.e. "main", "temp" or an attached database) containing the specified
+** table or NULL. If it is NULL, then all attached databases are searched
+** for the table using the same algorithm as the database engine uses to 
+** resolve unqualified table references.
+**
+** The third and fourth parameters to this function are the table and column 
+** name of the desired column, respectively. Neither of these parameters 
+** may be NULL.
+**
+** Meta information is returned by writing to the memory locations passed as
+** the 5th and subsequent parameters to this function. Any of these 
+** arguments may be NULL, in which case the corresponding element of meta 
+** information is ommitted.
+**
+** <pre>
+** Parameter     Output Type      Description
+** -----------------------------------
+**
+**   5th         const char*      Data type
+**   6th         const char*      Name of the default collation sequence 
+**   7th         int              True if the column has a NOT NULL constraint
+**   8th         int              True if the column is part of the PRIMARY KEY
+**   9th         int              True if the column is AUTOINCREMENT
+** </pre>
+**
+**
+** The memory pointed to by the character pointers returned for the 
+** declaration type and collation sequence is valid only until the next 
+** call to any sqlite API function.
+**
+** If the specified table is actually a view, then an error is returned.
+**
+** If the specified column is "rowid", "oid" or "_rowid_" and an 
+** INTEGER PRIMARY KEY column has been explicitly declared, then the output 
+** parameters are set for the explicitly declared column. If there is no
+** explicitly declared IPK column, then the output parameters are set as 
+** follows:
+**
+** <pre>
+**     data type: "INTEGER"
+**     collation sequence: "BINARY"
+**     not null: 0
+**     primary key: 1
+**     auto increment: 0
+** </pre>
+**
+** This function may load one or more schemas from database files. If an
+** error occurs during this process, or if the requested table or column
+** cannot be found, an SQLITE error code is returned and an error message
+** left in the database handle (to be retrieved using sqlite3_errmsg()).
+**
+** This API is only available if the library was compiled with the
+** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+);
+
+/*
+** CAPI3REF: Load An Extension {F12600}
+**
+** {F12601} The sqlite3_load_extension() interface
+** attempts to load an SQLite extension library contained in the file
+** zFile. {F12602} The entry point is zProc. {F12603} zProc may be 0
+** in which case the name of the entry point defaults
+** to "sqlite3_extension_init".
+**
+** {F12604} The sqlite3_load_extension() interface shall
+** return [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+**
+** {F12605}
+** If an error occurs and pzErrMsg is not 0, then the
+** sqlite3_load_extension() interface shall attempt to fill *pzErrMsg with 
+** error message text stored in memory obtained from [sqlite3_malloc()].
+** {END}  The calling function should free this memory
+** by calling [sqlite3_free()].
+**
+** {F12606}
+** Extension loading must be enabled using [sqlite3_enable_load_extension()]
+** prior to calling this API or an error will be returned.
+*/
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+);
+
+/*
+** CAPI3REF:  Enable Or Disable Extension Loading {F12620}
+**
+** So as not to open security holes in older applications that are
+** unprepared to deal with extension loading, and as a means of disabling
+** extension loading while evaluating user-entered SQL, the following
+** API is provided to turn the [sqlite3_load_extension()] mechanism on and
+** off.  {F12622} It is off by default. {END} See ticket #1863.
+**
+** {F12621} Call the sqlite3_enable_load_extension() routine
+** with onoff==1 to turn extension loading on
+** and call it with onoff==0 to turn it back off again. {END}
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+
+/*
+** CAPI3REF: Make Arrangements To Automatically Load An Extension {F12640}
+**
+** {F12641} This function
+** registers an extension entry point that is automatically invoked
+** whenever a new database connection is opened using
+** [sqlite3_open()], [sqlite3_open16()], or [sqlite3_open_v2()]. {END}
+**
+** This API can be invoked at program startup in order to register
+** one or more statically linked extensions that will be available
+** to all new database connections.
+**
+** {F12642} Duplicate extensions are detected so calling this routine multiple
+** times with the same extension is harmless.
+**
+** {F12643} This routine stores a pointer to the extension in an array
+** that is obtained from sqlite_malloc(). {END} If you run a memory leak
+** checker on your program and it reports a leak because of this
+** array, then invoke [sqlite3_reset_auto_extension()] prior
+** to shutdown to free the memory.
+**
+** {F12644} Automatic extensions apply across all threads. {END}
+**
+** This interface is experimental and is subject to change or
+** removal in future releases of SQLite.
+*/
+SQLITE_API int sqlite3_auto_extension(void *xEntryPoint);
+
+
+/*
+** CAPI3REF: Reset Automatic Extension Loading {F12660}
+**
+** {F12661} This function disables all previously registered
+** automatic extensions. {END}  This
+** routine undoes the effect of all prior [sqlite3_auto_extension()]
+** calls.
+**
+** {F12662} This call disabled automatic extensions in all threads. {END}
+**
+** This interface is experimental and is subject to change or
+** removal in future releases of SQLite.
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void);
+
+
+/*
+****** EXPERIMENTAL - subject to change without notice **************
+**
+** The interface to the virtual-table mechanism is currently considered
+** to be experimental.  The interface might change in incompatible ways.
+** If this is a problem for you, do not use the interface at this time.
+**
+** When the virtual-table mechanism stablizes, we will declare the
+** interface fixed, support it indefinitely, and remove this comment.
+*/
+
+/*
+** Structures used by the virtual table interface
+*/
+typedef struct sqlite3_vtab sqlite3_vtab;
+typedef struct sqlite3_index_info sqlite3_index_info;
+typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
+typedef struct sqlite3_module sqlite3_module;
+
+/*
+** CAPI3REF: Virtual Table Object {F18000}
+** KEYWORDS: sqlite3_module
+**
+** A module is a class of virtual tables.  Each module is defined
+** by an instance of the following structure.  This structure consists
+** mostly of methods for the module.
+*/
+struct sqlite3_module {
+  int iVersion;
+  int (*xCreate)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xConnect)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
+  int (*xDisconnect)(sqlite3_vtab *pVTab);
+  int (*xDestroy)(sqlite3_vtab *pVTab);
+  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
+  int (*xClose)(sqlite3_vtab_cursor*);
+  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
+                int argc, sqlite3_value **argv);
+  int (*xNext)(sqlite3_vtab_cursor*);
+  int (*xEof)(sqlite3_vtab_cursor*);
+  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
+  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
+  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
+  int (*xBegin)(sqlite3_vtab *pVTab);
+  int (*xSync)(sqlite3_vtab *pVTab);
+  int (*xCommit)(sqlite3_vtab *pVTab);
+  int (*xRollback)(sqlite3_vtab *pVTab);
+  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
+                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+                       void **ppArg);
+
+  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+};
+
+/*
+** CAPI3REF: Virtual Table Indexing Information {F18100}
+** KEYWORDS: sqlite3_index_info
+**
+** The sqlite3_index_info structure and its substructures is used to
+** pass information into and receive the reply from the xBestIndex
+** method of an sqlite3_module.  The fields under **Inputs** are the
+** inputs to xBestIndex and are read-only.  xBestIndex inserts its
+** results into the **Outputs** fields.
+**
+** The aConstraint[] array records WHERE clause constraints of the
+** form:
+**
+**         column OP expr
+**
+** Where OP is =, &lt;, &lt;=, &gt;, or &gt;=.  
+** The particular operator is stored
+** in aConstraint[].op.  The index of the column is stored in 
+** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
+** expr on the right-hand side can be evaluated (and thus the constraint
+** is usable) and false if it cannot.
+**
+** The optimizer automatically inverts terms of the form "expr OP column"
+** and makes other simplifications to the WHERE clause in an attempt to
+** get as many WHERE clause terms into the form shown above as possible.
+** The aConstraint[] array only reports WHERE clause terms in the correct
+** form that refer to the particular virtual table being queried.
+**
+** Information about the ORDER BY clause is stored in aOrderBy[].
+** Each term of aOrderBy records a column of the ORDER BY clause.
+**
+** The xBestIndex method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  If argvIndex>0 then
+** the right-hand side of the corresponding aConstraint[] is evaluated
+** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
+** is true, then the constraint is assumed to be fully handled by the
+** virtual table and is not checked again by SQLite.
+**
+** The idxNum and idxPtr values are recorded and passed into xFilter.
+** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
+**
+** The orderByConsumed means that output from xFilter will occur in
+** the correct order to satisfy the ORDER BY clause so that no separate
+** sorting step is required.
+**
+** The estimatedCost value is an estimate of the cost of doing the
+** particular lookup.  A full scan of a table with N entries should have
+** a cost of N.  A binary search of a table of N entries should have a
+** cost of approximately log(N).
+*/
+struct sqlite3_index_info {
+  /* Inputs */
+  int nConstraint;           /* Number of entries in aConstraint */
+  struct sqlite3_index_constraint {
+     int iColumn;              /* Column on left-hand side of constraint */
+     unsigned char op;         /* Constraint operator */
+     unsigned char usable;     /* True if this constraint is usable */
+     int iTermOffset;          /* Used internally - xBestIndex should ignore */
+  } *aConstraint;            /* Table of WHERE clause constraints */
+  int nOrderBy;              /* Number of terms in the ORDER BY clause */
+  struct sqlite3_index_orderby {
+     int iColumn;              /* Column number */
+     unsigned char desc;       /* True for DESC.  False for ASC. */
+  } *aOrderBy;               /* The ORDER BY clause */
+
+  /* Outputs */
+  struct sqlite3_index_constraint_usage {
+    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
+    unsigned char omit;      /* Do not code a test for this constraint */
+  } *aConstraintUsage;
+  int idxNum;                /* Number used to identify the index */
+  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
+  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
+  int orderByConsumed;       /* True if output is already ordered */
+  double estimatedCost;      /* Estimated cost of using this index */
+};
+#define SQLITE_INDEX_CONSTRAINT_EQ    2
+#define SQLITE_INDEX_CONSTRAINT_GT    4
+#define SQLITE_INDEX_CONSTRAINT_LE    8
+#define SQLITE_INDEX_CONSTRAINT_LT    16
+#define SQLITE_INDEX_CONSTRAINT_GE    32
+#define SQLITE_INDEX_CONSTRAINT_MATCH 64
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation {F18200}
+**
+** This routine is used to register a new module name with an SQLite
+** connection.  Module names must be registered before creating new
+** virtual tables on the module, or before using preexisting virtual
+** tables of the module.
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *,    /* Methods for the module */
+  void *                     /* Client data for xCreate/xConnect */
+);
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation {F18210}
+**
+** This routine is identical to the sqlite3_create_module() method above,
+** except that it allows a destructor function to be specified. It is
+** even more experimental than the rest of the virtual tables API.
+*/
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *,    /* Methods for the module */
+  void *,                    /* Client data for xCreate/xConnect */
+  void(*xDestroy)(void*)     /* Module destructor function */
+);
+
+/*
+** CAPI3REF: Virtual Table Instance Object {F18010}
+** KEYWORDS: sqlite3_vtab
+**
+** Every module implementation uses a subclass of the following structure
+** to describe a particular instance of the module.  Each subclass will
+** be tailored to the specific needs of the module implementation.   The
+** purpose of this superclass is to define certain fields that are common
+** to all module implementations.
+**
+** Virtual tables methods can set an error message by assigning a
+** string obtained from sqlite3_mprintf() to zErrMsg.  The method should
+** take care that any prior string is freed by a call to sqlite3_free()
+** prior to assigning a new string to zErrMsg.  After the error message
+** is delivered up to the client application, the string will be automatically
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.  Note
+** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
+** since virtual tables are commonly implemented in loadable extensions which
+** do not have access to sqlite3MPrintf() or sqlite3Free().
+*/
+struct sqlite3_vtab {
+  const sqlite3_module *pModule;  /* The module for this virtual table */
+  int nRef;                       /* Used internally */
+  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Virtual Table Cursor Object  {F18020}
+** KEYWORDS: sqlite3_vtab_cursor
+**
+** Every module implementation uses a subclass of the following structure
+** to describe cursors that point into the virtual table and are used
+** to loop through the virtual table.  Cursors are created using the
+** xOpen method of the module.  Each module implementation will define
+** the content of a cursor structure to suit its own needs.
+**
+** This superclass exists in order to define fields of the cursor that
+** are common to all implementations.
+*/
+struct sqlite3_vtab_cursor {
+  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Declare The Schema Of A Virtual Table {F18280}
+**
+** The xCreate and xConnect methods of a module use the following API
+** to declare the format (the names and datatypes of the columns) of
+** the virtual tables they implement.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
+
+/*
+** CAPI3REF: Overload A Function For A Virtual Table {F18300}
+**
+** Virtual tables can provide alternative implementations of functions
+** using the xFindFunction method.  But global versions of those functions
+** must exist in order to be overloaded.
+**
+** This API makes sure a global version of a function with a particular
+** name and number of parameters exists.  If no such function exists
+** before this API is called, a new function is created.  The implementation
+** of the new function always causes an exception to be thrown.  So
+** the new function is not good for anything by itself.  Its only
+** purpose is to be a place-holder function that can be overloaded
+** by virtual tables.
+**
+** This API should be considered part of the virtual table interface,
+** which is experimental and subject to change.
+*/
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+
+/*
+** The interface to the virtual-table mechanism defined above (back up
+** to a comment remarkably similar to this one) is currently considered
+** to be experimental.  The interface might change in incompatible ways.
+** If this is a problem for you, do not use the interface at this time.
+**
+** When the virtual-table mechanism stabilizes, we will declare the
+** interface fixed, support it indefinitely, and remove this comment.
+**
+****** EXPERIMENTAL - subject to change without notice **************
+*/
+
+/*
+** CAPI3REF: A Handle To An Open BLOB {F17800}
+**
+** An instance of this object represents an open BLOB on which
+** incremental I/O can be preformed.
+** Objects of this type are created by
+** [sqlite3_blob_open()] and destroyed by [sqlite3_blob_close()].
+** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** can be used to read or write small subsections of the blob.
+** The [sqlite3_blob_bytes()] interface returns the size of the
+** blob in bytes.
+*/
+typedef struct sqlite3_blob sqlite3_blob;
+
+/*
+** CAPI3REF: Open A BLOB For Incremental I/O {F17810}
+**
+** This interfaces opens a handle to the blob located
+** in row iRow, column zColumn, table zTable in database zDb;
+** in other words,  the same blob that would be selected by:
+**
+** <pre>
+**     SELECT zColumn FROM zDb.zTable WHERE rowid = iRow;
+** </pre> {END}
+**
+** If the flags parameter is non-zero, the blob is opened for 
+** read and write access. If it is zero, the blob is opened for read 
+** access.
+**
+** Note that the database name is not the filename that contains
+** the database but rather the symbolic name of the database that
+** is assigned when the database is connected using [ATTACH].
+** For the main database file, the database name is "main".  For
+** TEMP tables, the database name is "temp".
+**
+** On success, [SQLITE_OK] is returned and the new 
+** [sqlite3_blob | blob handle] is written to *ppBlob. 
+** Otherwise an error code is returned and 
+** any value written to *ppBlob should not be used by the caller.
+** This function sets the database-handle error code and message
+** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()].
+** 
+** INVARIANTS:
+**
+** {F17813} A successful invocation of the [sqlite3_blob_open(D,B,T,C,R,F,P)]
+**          interface opens an [sqlite3_blob] object P on the blob
+**          in column C of table T in database B on [database connection] D.
+**
+** {F17814} A successful invocation of [sqlite3_blob_open(D,...)] starts
+**          a new transaction on [database connection] D if that connection
+**          is not already in a transaction.
+**
+** {F17816} The [sqlite3_blob_open(D,B,T,C,R,F,P)] interface opens the blob
+**          for read and write access if and only if the F parameter
+**          is non-zero.
+**
+** {F17819} The [sqlite3_blob_open()] interface returns [SQLITE_OK] on 
+**          success and an appropriate [error code] on failure.
+**
+** {F17821} If an error occurs during evaluation of [sqlite3_blob_open(D,...)]
+**          then subsequent calls to [sqlite3_errcode(D)],
+**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
+**          information approprate for that error.
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3*,
+  const char *zDb,
+  const char *zTable,
+  const char *zColumn,
+  sqlite3_int64 iRow,
+  int flags,
+  sqlite3_blob **ppBlob
+);
+
+/*
+** CAPI3REF:  Close A BLOB Handle {F17830}
+**
+** Close an open [sqlite3_blob | blob handle].
+**
+** Closing a BLOB shall cause the current transaction to commit
+** if there are no other BLOBs, no pending prepared statements, and the
+** database connection is in autocommit mode.
+** If any writes were made to the BLOB, they might be held in cache
+** until the close operation if they will fit. {END}
+** Closing the BLOB often forces the changes
+** out to disk and so if any I/O errors occur, they will likely occur
+** at the time when the BLOB is closed.  {F17833} Any errors that occur during
+** closing are reported as a non-zero return value.
+**
+** The BLOB is closed unconditionally.  Even if this routine returns
+** an error code, the BLOB is still closed.
+**
+** INVARIANTS:
+**
+** {F17833} The [sqlite3_blob_close(P)] interface closes an
+**          [sqlite3_blob] object P previously opened using
+**          [sqlite3_blob_open()].
+**
+** {F17836} Closing an [sqlite3_blob] object using
+**          [sqlite3_blob_close()] shall cause the current transaction to
+**          commit if there are no other open [sqlite3_blob] objects
+**          or [prepared statements] on the same [database connection] and
+**          the [database connection] is in
+**          [sqlite3_get_autocommit | autocommit mode].
+**
+** {F17839} The [sqlite3_blob_close(P)] interfaces closes the 
+**          [sqlite3_blob] object P unconditionally, even if
+**          [sqlite3_blob_close(P)] returns something other than [SQLITE_OK].
+**          
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
+
+/*
+** CAPI3REF:  Return The Size Of An Open BLOB {F17840}
+**
+** Return the size in bytes of the blob accessible via the open 
+** [sqlite3_blob] object in its only argument.
+**
+** INVARIANTS:
+**
+** {F17843} The [sqlite3_blob_bytes(P)] interface returns the size
+**          in bytes of the BLOB that the [sqlite3_blob] object P
+**          refers to.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
+
+/*
+** CAPI3REF:  Read Data From A BLOB Incrementally {F17850}
+**
+** This function is used to read data from an open 
+** [sqlite3_blob | blob-handle] into a caller supplied buffer.
+** N bytes of data are copied into buffer
+** Z from the open blob, starting at offset iOffset.
+**
+** If offset iOffset is less than N bytes from the end of the blob, 
+** [SQLITE_ERROR] is returned and no data is read.  If N or iOffset is
+** less than zero [SQLITE_ERROR] is returned and no data is read.
+**
+** On success, SQLITE_OK is returned. Otherwise, an 
+** [error code] or an [extended error code] is returned.
+**
+** INVARIANTS:
+**
+** {F17853} The [sqlite3_blob_read(P,Z,N,X)] interface reads N bytes
+**          beginning at offset X from
+**          the blob that [sqlite3_blob] object P refers to
+**          and writes those N bytes into buffer Z.
+**
+** {F17856} In [sqlite3_blob_read(P,Z,N,X)] if the size of the blob
+**          is less than N+X bytes, then the function returns [SQLITE_ERROR]
+**          and nothing is read from the blob.
+**
+** {F17859} In [sqlite3_blob_read(P,Z,N,X)] if X or N is less than zero
+**          then the function returns [SQLITE_ERROR]
+**          and nothing is read from the blob.
+**
+** {F17862} The [sqlite3_blob_read(P,Z,N,X)] interface returns [SQLITE_OK]
+**          if N bytes where successfully read into buffer Z.
+**
+** {F17865} If the requested read could not be completed,
+**          the [sqlite3_blob_read(P,Z,N,X)] interface returns an
+**          appropriate [error code] or [extended error code].
+**
+** {F17868} If an error occurs during evaluation of [sqlite3_blob_read(P,...)]
+**          then subsequent calls to [sqlite3_errcode(D)],
+**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
+**          information approprate for that error, where D is the
+**          database handle that was used to open blob handle P.
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+
+/*
+** CAPI3REF:  Write Data Into A BLOB Incrementally {F17870}
+**
+** This function is used to write data into an open 
+** [sqlite3_blob | blob-handle] from a user supplied buffer.
+** n bytes of data are copied from the buffer
+** pointed to by z into the open blob, starting at offset iOffset.
+**
+** If the [sqlite3_blob | blob-handle] passed as the first argument
+** was not opened for writing (the flags parameter to [sqlite3_blob_open()]
+*** was zero), this function returns [SQLITE_READONLY].
+**
+** This function may only modify the contents of the blob; it is
+** not possible to increase the size of a blob using this API.
+** If offset iOffset is less than n bytes from the end of the blob, 
+** [SQLITE_ERROR] is returned and no data is written.  If n is
+** less than zero [SQLITE_ERROR] is returned and no data is written.
+**
+** On success, SQLITE_OK is returned. Otherwise, an 
+** [error code] or an [extended error code] is returned.
+**
+** INVARIANTS:
+**
+** {F17873} The [sqlite3_blob_write(P,Z,N,X)] interface writes N bytes
+**          from buffer Z into
+**          the blob that [sqlite3_blob] object P refers to
+**          beginning at an offset of X into the blob.
+**
+** {F17875} The [sqlite3_blob_write(P,Z,N,X)] interface returns
+**          [SQLITE_READONLY] if the [sqlite3_blob] object P was
+**          [sqlite3_blob_open | opened] for reading only.
+**
+** {F17876} In [sqlite3_blob_write(P,Z,N,X)] if the size of the blob
+**          is less than N+X bytes, then the function returns [SQLITE_ERROR]
+**          and nothing is written into the blob.
+**
+** {F17879} In [sqlite3_blob_write(P,Z,N,X)] if X or N is less than zero
+**          then the function returns [SQLITE_ERROR]
+**          and nothing is written into the blob.
+**
+** {F17882} The [sqlite3_blob_write(P,Z,N,X)] interface returns [SQLITE_OK]
+**          if N bytes where successfully written into blob.
+**
+** {F17885} If the requested write could not be completed,
+**          the [sqlite3_blob_write(P,Z,N,X)] interface returns an
+**          appropriate [error code] or [extended error code].
+**
+** {F17888} If an error occurs during evaluation of [sqlite3_blob_write(D,...)]
+**          then subsequent calls to [sqlite3_errcode(D)],
+**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
+**          information approprate for that error.
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+
+/*
+** CAPI3REF:  Virtual File System Objects {F11200}
+**
+** A virtual filesystem (VFS) is an [sqlite3_vfs] object
+** that SQLite uses to interact
+** with the underlying operating system.  Most SQLite builds come with a
+** single default VFS that is appropriate for the host computer.
+** New VFSes can be registered and existing VFSes can be unregistered.
+** The following interfaces are provided.
+**
+** The sqlite3_vfs_find() interface returns a pointer to 
+** a VFS given its name.  Names are case sensitive.
+** Names are zero-terminated UTF-8 strings.
+** If there is no match, a NULL
+** pointer is returned.  If zVfsName is NULL then the default 
+** VFS is returned. 
+**
+** New VFSes are registered with sqlite3_vfs_register().
+** Each new VFS becomes the default VFS if the makeDflt flag is set.
+** The same VFS can be registered multiple times without injury.
+** To make an existing VFS into the default VFS, register it again
+** with the makeDflt flag set.  If two different VFSes with the
+** same name are registered, the behavior is undefined.  If a
+** VFS is registered with a name that is NULL or an empty string,
+** then the behavior is undefined.
+** 
+** Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.
+**
+** INVARIANTS:
+**
+** {F11203} The [sqlite3_vfs_find(N)] interface returns a pointer to the
+**          registered [sqlite3_vfs] object whose name exactly matches
+**          the zero-terminated UTF-8 string N, or it returns NULL if
+**          there is no match.
+**
+** {F11206} If the N parameter to [sqlite3_vfs_find(N)] is NULL then
+**          the function returns a pointer to the default [sqlite3_vfs]
+**          object if there is one, or NULL if there is no default 
+**          [sqlite3_vfs] object.
+**
+** {F11209} The [sqlite3_vfs_register(P,F)] interface registers the
+**          well-formed [sqlite3_vfs] object P using the name given
+**          by the zName field of the object.
+**
+** {F11212} Using the [sqlite3_vfs_register(P,F)] interface to register
+**          the same [sqlite3_vfs] object multiple times is a harmless no-op.
+**
+** {F11215} The [sqlite3_vfs_register(P,F)] interface makes the
+**          the [sqlite3_vfs] object P the default [sqlite3_vfs] object
+**          if F is non-zero.
+**
+** {F11218} The [sqlite3_vfs_unregister(P)] interface unregisters the
+**          [sqlite3_vfs] object P so that it is no longer returned by
+**          subsequent calls to [sqlite3_vfs_find()].
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
+
+/*
+** CAPI3REF: Mutexes {F17000}
+**
+** The SQLite core uses these routines for thread
+** synchronization.  Though they are intended for internal
+** use by SQLite, code that links against SQLite is
+** permitted to use any of these routines.
+**
+** The SQLite source code contains multiple implementations 
+** of these mutex routines.  An appropriate implementation
+** is selected automatically at compile-time.  The following
+** implementations are available in the SQLite core:
+**
+** <ul>
+** <li>   SQLITE_MUTEX_OS2
+** <li>   SQLITE_MUTEX_PTHREAD
+** <li>   SQLITE_MUTEX_W32
+** <li>   SQLITE_MUTEX_NOOP
+** </ul>
+**
+** The SQLITE_MUTEX_NOOP implementation is a set of routines 
+** that does no real locking and is appropriate for use in 
+** a single-threaded application.  The SQLITE_MUTEX_OS2,
+** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
+** are appropriate for use on os/2, unix, and windows.
+** 
+** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
+** implementation is included with the library.  The
+** mutex interface routines defined here become external
+** references in the SQLite library for which implementations
+** must be provided by the application.  This facility allows an
+** application that links against SQLite to provide its own mutex
+** implementation without having to modify the SQLite core.
+**
+** {F17011} The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. {F17012} If it returns NULL
+** that means that a mutex could not be allocated. {F17013} SQLite
+** will unwind its stack and return an error. {F17014} The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MASTER
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_MEM2
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_LRU2
+** </ul> {END}
+**
+** {F17015} The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  {F17016} But SQLite will only request a recursive mutex in
+** cases where it really needs one.  {END} If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** {F17017} The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex. {END}  Four static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** {F17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  {F17034} But for the static 
+** mutex types, the same mutex is returned on every call that has
+** the same type number. {END}
+**
+** {F17019} The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex. {F17020} SQLite is careful to deallocate every
+** dynamic mutex that it allocates. {U17021} The dynamic mutexes must not be in 
+** use when they are deallocated. {U17022} Attempting to deallocate a static
+** mutex results in undefined behavior. {F17023} SQLite never deallocates
+** a static mutex. {END}
+**
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex. {F17024} If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY. {F17025}  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  {F17026} Mutexes created using
+** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
+** {F17027} In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  {U17028} If the same thread tries to enter any other
+** kind of mutex more than once, the behavior is undefined.
+** {F17029} SQLite will never exhibit
+** such behavior in its own use of mutexes. {END}
+**
+** Some systems (ex: windows95) do not the operation implemented by
+** sqlite3_mutex_try().  On those systems, sqlite3_mutex_try() will
+** always return SQLITE_BUSY.  {F17030} The SQLite core only ever uses
+** sqlite3_mutex_try() as an optimization so this is acceptable behavior. {END}
+**
+** {F17031} The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  {U17032} The behavior
+** is undefined if the mutex is not currently entered by the
+** calling thread or is not currently allocated.  {F17033} SQLite will
+** never do either. {END}
+**
+** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Verifcation Routines {F17080}
+**
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
+** are intended for use inside assert() statements. {F17081} The SQLite core
+** never uses these routines except inside an assert() and applications
+** are advised to follow the lead of the core.  {F17082} The core only
+** provides implementations for these routines when it is compiled
+** with the SQLITE_DEBUG flag.  {U17087} External mutex implementations
+** are only required to provide these routines if SQLITE_DEBUG is
+** defined and if NDEBUG is not defined.
+**
+** {F17083} These routines should return true if the mutex in their argument
+** is held or not held, respectively, by the calling thread. {END}
+**
+** {X17084} The implementation is not required to provided versions of these
+** routines that actually work.
+** If the implementation does not provide working
+** versions of these routines, it should at least provide stubs
+** that always return true so that one does not get spurious
+** assertion failures. {END}
+**
+** {F17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.  {END} This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But the
+** the reason the mutex does not exist is because the build is not
+** using mutexes.  And we do not want the assert() containing the
+** call to sqlite3_mutex_held() to fail, so a non-zero return is
+** the appropriate thing to do.  {F17086} The sqlite3_mutex_notheld() 
+** interface should also return 1 when given a NULL pointer.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Types {F17001}
+**
+** {F17002} The [sqlite3_mutex_alloc()] interface takes a single argument
+** which is one of these integer constants. {END}
+*/
+#define SQLITE_MUTEX_FAST             0
+#define SQLITE_MUTEX_RECURSIVE        1
+#define SQLITE_MUTEX_STATIC_MASTER    2
+#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
+#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
+#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
+
+/*
+** CAPI3REF: Low-Level Control Of Database Files {F11300}
+**
+** {F11301} The [sqlite3_file_control()] interface makes a direct call to the
+** xFileControl method for the [sqlite3_io_methods] object associated
+** with a particular database identified by the second argument. {F11302} The
+** name of the database is the name assigned to the database by the
+** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
+** database. {F11303} To control the main database file, use the name "main"
+** or a NULL pointer. {F11304} The third and fourth parameters to this routine
+** are passed directly through to the second and third parameters of
+** the xFileControl method.  {F11305} The return value of the xFileControl
+** method becomes the return value of this routine.
+**
+** {F11306} If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned. {F11307} This error
+** code is not remembered and will not be recalled by [sqlite3_errcode()]
+** or [sqlite3_errmsg()]. {U11308} The underlying xFileControl method might
+** also return SQLITE_ERROR.  {U11309} There is no way to distinguish between
+** an incorrect zDbName and an SQLITE_ERROR return from the underlying
+** xFileControl method. {END}
+**
+** See also: [SQLITE_FCNTL_LOCKSTATE]
+*/
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+
+/*
+** CAPI3REF: Testing Interface {F11400}
+**
+** The sqlite3_test_control() interface is used to read out internal
+** state of SQLite and to inject faults into SQLite for testing
+** purposes.  The first parameter a operation code that determines
+** the number, meaning, and operation of all subsequent parameters.
+**
+** This interface is not for use by applications.  It exists solely
+** for verifying the correct operation of the SQLite library.  Depending
+** on how the SQLite library is compiled, this interface might not exist.
+**
+** The details of the operation codes, their meanings, the parameters
+** they take, and what they do are all subject to change without notice.
+** Unlike most of the SQLite API, this function is not guaranteed to
+** operate consistently from one release to the next.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...);
+
+/*
+** CAPI3REF: Testing Interface Operation Codes {F11410}
+**
+** These constants are the valid operation code parameters used
+** as the first argument to [sqlite3_test_control()].
+**
+** These parameters and their meansing are subject to change
+** without notice.  These values are for testing purposes only.
+** Applications should not use any of these parameters or the
+** [sqlite3_test_control()] interface.
+*/
+#define SQLITE_TESTCTRL_FAULT_CONFIG             1
+#define SQLITE_TESTCTRL_FAULT_FAILURES           2
+#define SQLITE_TESTCTRL_FAULT_BENIGN_FAILURES    3
+#define SQLITE_TESTCTRL_FAULT_PENDING            4
+#define SQLITE_TESTCTRL_PRNG_SAVE                5
+#define SQLITE_TESTCTRL_PRNG_RESTORE             6
+#define SQLITE_TESTCTRL_PRNG_RESET               7
+#define SQLITE_TESTCTRL_BITVEC_TEST              8
+
+
+/*
+** Undo the hack that converts floating point types to integer for
+** builds on processors without floating point support.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# undef double
+#endif
+
+#if 0
+}  /* End of the 'extern "C"' block */
+#endif
+#endif
+
+/************** End of sqlite3.h *********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include hash.h in the middle of sqliteInt.h ******************/
+/************** Begin file hash.h ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implemenation
+** used in SQLite.
+**
+** $Id: hash.h,v 1.11 2007/09/04 14:31:47 danielk1977 Exp $
+*/
+#ifndef _SQLITE_HASH_H_
+#define _SQLITE_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct Hash Hash;
+typedef struct HashElem HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, many of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+*/
+struct Hash {
+  char keyClass;          /* SQLITE_HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  int htsize;             /* Number of buckets in the hash table */
+  HashElem *first;        /* The first element of the array */
+  struct _ht {            /* the hash table */
+    int count;               /* Number of entries with this hash */
+    HashElem *chain;         /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following 
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct HashElem {
+  HashElem *next, *prev;   /* Next and previous elements in the table */
+  void *data;              /* Data associated with this element */
+  void *pKey; int nKey;    /* Key associated with this element */
+};
+
+/*
+** There are 4 different modes of operation for a hash table:
+**
+**   SQLITE_HASH_INT         nKey is used as the key and pKey is ignored.
+**
+**   SQLITE_HASH_POINTER     pKey is used as the key and nKey is ignored.
+**
+**   SQLITE_HASH_STRING      pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is ignored in comparisons.
+**
+**   SQLITE_HASH_BINARY      pKey points to binary data nKey bytes long. 
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made for SQLITE_HASH_STRING and SQLITE_HASH_BINARY
+** if the copyKey parameter to HashInit is 1.  
+*/
+/* #define SQLITE_HASH_INT       1 // NOT USED */
+/* #define SQLITE_HASH_POINTER   2 // NOT USED */
+#define SQLITE_HASH_STRING    3
+#define SQLITE_HASH_BINARY    4
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash*, int keytype, int copyKey);
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE HashElem *sqlite3HashFindElem(const Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3HashClear(Hash*);
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Hash h;
+**   HashElem *p;
+**   ...
+**   for(p=sqliteHashFirst(&h); p; p=sqliteHashNext(p)){
+**     SomeStructure *pData = sqliteHashData(p);
+**     // do something with pData
+**   }
+*/
+#define sqliteHashFirst(H)  ((H)->first)
+#define sqliteHashNext(E)   ((E)->next)
+#define sqliteHashData(E)   ((E)->data)
+#define sqliteHashKey(E)    ((E)->pKey)
+#define sqliteHashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define sqliteHashCount(H)  ((H)->count)
+
+#endif /* _SQLITE_HASH_H_ */
+
+/************** End of hash.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include parse.h in the middle of sqliteInt.h *****************/
+/************** Begin file parse.h *******************************************/
+#define TK_SEMI                            1
+#define TK_EXPLAIN                         2
+#define TK_QUERY                           3
+#define TK_PLAN                            4
+#define TK_BEGIN                           5
+#define TK_TRANSACTION                     6
+#define TK_DEFERRED                        7
+#define TK_IMMEDIATE                       8
+#define TK_EXCLUSIVE                       9
+#define TK_COMMIT                         10
+#define TK_END                            11
+#define TK_ROLLBACK                       12
+#define TK_CREATE                         13
+#define TK_TABLE                          14
+#define TK_IF                             15
+#define TK_NOT                            16
+#define TK_EXISTS                         17
+#define TK_TEMP                           18
+#define TK_LP                             19
+#define TK_RP                             20
+#define TK_AS                             21
+#define TK_COMMA                          22
+#define TK_ID                             23
+#define TK_ABORT                          24
+#define TK_AFTER                          25
+#define TK_ANALYZE                        26
+#define TK_ASC                            27
+#define TK_ATTACH                         28
+#define TK_BEFORE                         29
+#define TK_CASCADE                        30
+#define TK_CAST                           31
+#define TK_CONFLICT                       32
+#define TK_DATABASE                       33
+#define TK_DESC                           34
+#define TK_DETACH                         35
+#define TK_EACH                           36
+#define TK_FAIL                           37
+#define TK_FOR                            38
+#define TK_IGNORE                         39
+#define TK_INITIALLY                      40
+#define TK_INSTEAD                        41
+#define TK_LIKE_KW                        42
+#define TK_MATCH                          43
+#define TK_KEY                            44
+#define TK_OF                             45
+#define TK_OFFSET                         46
+#define TK_PRAGMA                         47
+#define TK_RAISE                          48
+#define TK_REPLACE                        49
+#define TK_RESTRICT                       50
+#define TK_ROW                            51
+#define TK_TRIGGER                        52
+#define TK_VACUUM                         53
+#define TK_VIEW                           54
+#define TK_VIRTUAL                        55
+#define TK_REINDEX                        56
+#define TK_RENAME                         57
+#define TK_CTIME_KW                       58
+#define TK_ANY                            59
+#define TK_OR                             60
+#define TK_AND                            61
+#define TK_IS                             62
+#define TK_BETWEEN                        63
+#define TK_IN                             64
+#define TK_ISNULL                         65
+#define TK_NOTNULL                        66
+#define TK_NE                             67
+#define TK_EQ                             68
+#define TK_GT                             69
+#define TK_LE                             70
+#define TK_LT                             71
+#define TK_GE                             72
+#define TK_ESCAPE                         73
+#define TK_BITAND                         74
+#define TK_BITOR                          75
+#define TK_LSHIFT                         76
+#define TK_RSHIFT                         77
+#define TK_PLUS                           78
+#define TK_MINUS                          79
+#define TK_STAR                           80
+#define TK_SLASH                          81
+#define TK_REM                            82
+#define TK_CONCAT                         83
+#define TK_COLLATE                        84
+#define TK_UMINUS                         85
+#define TK_UPLUS                          86
+#define TK_BITNOT                         87
+#define TK_STRING                         88
+#define TK_JOIN_KW                        89
+#define TK_CONSTRAINT                     90
+#define TK_DEFAULT                        91
+#define TK_NULL                           92
+#define TK_PRIMARY                        93
+#define TK_UNIQUE                         94
+#define TK_CHECK                          95
+#define TK_REFERENCES                     96
+#define TK_AUTOINCR                       97
+#define TK_ON                             98
+#define TK_DELETE                         99
+#define TK_UPDATE                         100
+#define TK_INSERT                         101
+#define TK_SET                            102
+#define TK_DEFERRABLE                     103
+#define TK_FOREIGN                        104
+#define TK_DROP                           105
+#define TK_UNION                          106
+#define TK_ALL                            107
+#define TK_EXCEPT                         108
+#define TK_INTERSECT                      109
+#define TK_SELECT                         110
+#define TK_DISTINCT                       111
+#define TK_DOT                            112
+#define TK_FROM                           113
+#define TK_JOIN                           114
+#define TK_USING                          115
+#define TK_ORDER                          116
+#define TK_BY                             117
+#define TK_GROUP                          118
+#define TK_HAVING                         119
+#define TK_LIMIT                          120
+#define TK_WHERE                          121
+#define TK_INTO                           122
+#define TK_VALUES                         123
+#define TK_INTEGER                        124
+#define TK_FLOAT                          125
+#define TK_BLOB                           126
+#define TK_REGISTER                       127
+#define TK_VARIABLE                       128
+#define TK_CASE                           129
+#define TK_WHEN                           130
+#define TK_THEN                           131
+#define TK_ELSE                           132
+#define TK_INDEX                          133
+#define TK_ALTER                          134
+#define TK_TO                             135
+#define TK_ADD                            136
+#define TK_COLUMNKW                       137
+#define TK_TO_TEXT                        138
+#define TK_TO_BLOB                        139
+#define TK_TO_NUMERIC                     140
+#define TK_TO_INT                         141
+#define TK_TO_REAL                        142
+#define TK_END_OF_FILE                    143
+#define TK_ILLEGAL                        144
+#define TK_SPACE                          145
+#define TK_UNCLOSED_STRING                146
+#define TK_COMMENT                        147
+#define TK_FUNCTION                       148
+#define TK_COLUMN                         149
+#define TK_AGG_FUNCTION                   150
+#define TK_AGG_COLUMN                     151
+#define TK_CONST_FUNC                     152
+
+/************** End of parse.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <stddef.h>
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite_int64
+# define LONGDOUBLE_TYPE sqlite_int64
+# ifndef SQLITE_BIG_DBL
+#   define SQLITE_BIG_DBL (0x7fffffffffffffff)
+# endif
+# define SQLITE_OMIT_DATETIME_FUNCS 1
+# define SQLITE_OMIT_TRACE 1
+# undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+#endif
+#ifndef SQLITE_BIG_DBL
+# define SQLITE_BIG_DBL (1e99)
+#endif
+
+/*
+** OMIT_TEMPDB is set to 1 if SQLITE_OMIT_TEMPDB is defined, or 0
+** afterward. Having this macro allows us to cause the C compiler 
+** to omit code used by TEMP tables without messy #ifndef statements.
+*/
+#ifdef SQLITE_OMIT_TEMPDB
+#define OMIT_TEMPDB 1
+#else
+#define OMIT_TEMPDB 0
+#endif
+
+/*
+** If the following macro is set to 1, then NULL values are considered
+** distinct when determining whether or not two entries are the same
+** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
+** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
+** is the way things are suppose to work.
+**
+** If the following macro is set to 0, the NULLs are indistinct for
+** a UNIQUE index.  In this mode, you can only have a single NULL entry
+** for a column declared UNIQUE.  This is the way Informix and SQL Server
+** work.
+*/
+#define NULL_DISTINCT_FOR_UNIQUE 1
+
+/*
+** The "file format" number is an integer that is incremented whenever
+** the VDBE-level file format changes.  The following macros define the
+** the default file format for new databases and the maximum file format
+** that the library can read.
+*/
+#define SQLITE_MAX_FILE_FORMAT 4
+#ifndef SQLITE_DEFAULT_FILE_FORMAT
+# define SQLITE_DEFAULT_FILE_FORMAT 1
+#endif
+
+/*
+** Provide a default value for TEMP_STORE in case it is not specified
+** on the command-line
+*/
+#ifndef TEMP_STORE
+# define TEMP_STORE 1
+#endif
+
+/*
+** GCC does not define the offsetof() macro so we'll have to do it
+** ourselves.
+*/
+#ifndef offsetof
+#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
+#endif
+
+/*
+** Check to see if this machine uses EBCDIC.  (Yes, believe it or
+** not, there are still machines out there that use EBCDIC.)
+*/
+#if 'A' == '\301'
+# define SQLITE_EBCDIC 1
+#else
+# define SQLITE_ASCII 1
+#endif
+
+/*
+** Integers of known sizes.  These typedefs might change for architectures
+** where the sizes very.  Preprocessor macros are available so that the
+** types can be conveniently redefined at compile-type.  Like this:
+**
+**         cc '-DUINTPTR_TYPE=long long int' ...
+*/
+#ifndef UINT32_TYPE
+# ifdef HAVE_UINT32_T
+#  define UINT32_TYPE uint32_t
+# else
+#  define UINT32_TYPE unsigned int
+# endif
+#endif
+#ifndef UINT16_TYPE
+# ifdef HAVE_UINT16_T
+#  define UINT16_TYPE uint16_t
+# else
+#  define UINT16_TYPE unsigned short int
+# endif
+#endif
+#ifndef INT16_TYPE
+# ifdef HAVE_INT16_T
+#  define INT16_TYPE int16_t
+# else
+#  define INT16_TYPE short int
+# endif
+#endif
+#ifndef UINT8_TYPE
+# ifdef HAVE_UINT8_T
+#  define UINT8_TYPE uint8_t
+# else
+#  define UINT8_TYPE unsigned char
+# endif
+#endif
+#ifndef INT8_TYPE
+# ifdef HAVE_INT8_T
+#  define INT8_TYPE int8_t
+# else
+#  define INT8_TYPE signed char
+# endif
+#endif
+#ifndef LONGDOUBLE_TYPE
+# define LONGDOUBLE_TYPE long double
+#endif
+typedef sqlite_int64 i64;          /* 8-byte signed integer */
+typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */
+typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
+typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
+typedef INT16_TYPE i16;            /* 2-byte signed integer */
+typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
+typedef UINT8_TYPE i8;             /* 1-byte signed integer */
+
+/*
+** Macros to determine whether the machine is big or little endian,
+** evaluated at runtime.
+*/
+#ifdef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const int sqlite3one;
+#else
+SQLITE_PRIVATE const int sqlite3one;
+#endif
+#if defined(i386) || defined(__i386__) || defined(_M_IX86)
+# define SQLITE_BIGENDIAN    0
+# define SQLITE_LITTLEENDIAN 1
+# define SQLITE_UTF16NATIVE  SQLITE_UTF16LE
+#else
+# define SQLITE_BIGENDIAN    (*(char *)(&sqlite3one)==0)
+# define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)
+# define SQLITE_UTF16NATIVE (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)
+#endif
+
+/*
+** Constants for the largest and smallest possible 64-bit signed integers.
+** These macros are designed to work correctly on both 32-bit and 64-bit
+** compilers.
+*/
+#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+/*
+** An instance of the following structure is used to store the busy-handler
+** callback for a given sqlite handle. 
+**
+** The sqlite.busyHandler member of the sqlite struct contains the busy
+** callback for the database handle. Each pager opened via the sqlite
+** handle is passed a pointer to sqlite.busyHandler. The busy-handler
+** callback is currently invoked only from within pager.c.
+*/
+typedef struct BusyHandler BusyHandler;
+struct BusyHandler {
+  int (*xFunc)(void *,int);  /* The busy callback */
+  void *pArg;                /* First arg to busy callback */
+  int nBusy;                 /* Incremented with each busy call */
+};
+
+/*
+** Name of the master database table.  The master database table
+** is a special table that holds the names and attributes of all
+** user tables and indices.
+*/
+#define MASTER_NAME       "sqlite_master"
+#define TEMP_MASTER_NAME  "sqlite_temp_master"
+
+/*
+** The root-page of the master database table.
+*/
+#define MASTER_ROOT       1
+
+/*
+** The name of the schema table.
+*/
+#define SCHEMA_TABLE(x)  ((!OMIT_TEMPDB)&&(x==1)?TEMP_MASTER_NAME:MASTER_NAME)
+
+/*
+** A convenience macro that returns the number of elements in
+** an array.
+*/
+#define ArraySize(X)    (sizeof(X)/sizeof(X[0]))
+
+/*
+** Forward references to structures
+*/
+typedef struct AggInfo AggInfo;
+typedef struct AuthContext AuthContext;
+typedef struct Bitvec Bitvec;
+typedef struct CollSeq CollSeq;
+typedef struct Column Column;
+typedef struct Db Db;
+typedef struct Schema Schema;
+typedef struct Expr Expr;
+typedef struct ExprList ExprList;
+typedef struct FKey FKey;
+typedef struct FuncDef FuncDef;
+typedef struct IdList IdList;
+typedef struct Index Index;
+typedef struct KeyClass KeyClass;
+typedef struct KeyInfo KeyInfo;
+typedef struct Module Module;
+typedef struct NameContext NameContext;
+typedef struct Parse Parse;
+typedef struct Select Select;
+typedef struct SrcList SrcList;
+typedef struct StrAccum StrAccum;
+typedef struct Table Table;
+typedef struct TableLock TableLock;
+typedef struct Token Token;
+typedef struct TriggerStack TriggerStack;
+typedef struct TriggerStep TriggerStep;
+typedef struct Trigger Trigger;
+typedef struct WhereInfo WhereInfo;
+typedef struct WhereLevel WhereLevel;
+
+/*
+** Defer sourcing vdbe.h and btree.h until after the "u8" and 
+** "BusyHandler" typedefs. vdbe.h also requires a few of the opaque
+** pointer types (i.e. FuncDef) defined above.
+*/
+/************** Include btree.h in the middle of sqliteInt.h *****************/
+/************** Begin file btree.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite B-Tree file
+** subsystem.  See comments in the source code for a detailed description
+** of what each interface routine does.
+**
+** @(#) $Id: btree.h,v 1.98 2008/04/26 13:39:47 drh Exp $
+*/
+#ifndef _BTREE_H_
+#define _BTREE_H_
+
+/* TODO: This definition is just included so other modules compile. It
+** needs to be revisited.
+*/
+#define SQLITE_N_BTREE_META 10
+
+/*
+** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
+** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
+*/
+#ifndef SQLITE_DEFAULT_AUTOVACUUM
+  #define SQLITE_DEFAULT_AUTOVACUUM 0
+#endif
+
+#define BTREE_AUTOVACUUM_NONE 0        /* Do not do auto-vacuum */
+#define BTREE_AUTOVACUUM_FULL 1        /* Do full auto-vacuum */
+#define BTREE_AUTOVACUUM_INCR 2        /* Incremental vacuum */
+
+/*
+** Forward declarations of structure
+*/
+typedef struct Btree Btree;
+typedef struct BtCursor BtCursor;
+typedef struct BtShared BtShared;
+typedef struct BtreeMutexArray BtreeMutexArray;
+
+/*
+** This structure records all of the Btrees that need to hold
+** a mutex before we enter sqlite3VdbeExec().  The Btrees are
+** are placed in aBtree[] in order of aBtree[]->pBt.  That way,
+** we can always lock and unlock them all quickly.
+*/
+struct BtreeMutexArray {
+  int nMutex;
+  Btree *aBtree[SQLITE_MAX_ATTACHED+1];
+};
+
+
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  const char *zFilename,   /* Name of database file to open */
+  sqlite3 *db,             /* Associated database connection */
+  Btree **,                /* Return open Btree* here */
+  int flags,               /* Flags */
+  int vfsFlags             /* Flags passed through to VFS open */
+);
+
+/* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the
+** following values.
+**
+** NOTE:  These values must match the corresponding PAGER_ values in
+** pager.h.
+*/
+#define BTREE_OMIT_JOURNAL  1  /* Do not use journal.  No argument */
+#define BTREE_NO_READLOCK   2  /* Omit readlocks on readonly files */
+#define BTREE_MEMORY        4  /* In-memory DB.  No argument */
+#define BTREE_READONLY      8  /* Open the database in read-only mode */
+#define BTREE_READWRITE    16  /* Open for both reading and writing */
+#define BTREE_CREATE       32  /* Create the database if it does not exist */
+
+/* Additional values for the 4th argument of sqlite3BtreeOpen that
+** are not associated with PAGER_ values.
+*/
+#define BTREE_PRIVATE      64  /* Never share with other connections */
+
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *, int);
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeCommitStmt(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeRollbackStmt(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree*, int*, int flags);
+SQLITE_PRIVATE int sqlite3BtreeIsInTrans(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeIsInStmt(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree*);
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *, int, u8);
+
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *);
+SQLITE_PRIVATE const char *sqlite3BtreeGetDirname(Btree *);
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *, Btree *);
+
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *);
+
+/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
+** of the following flags:
+*/
+#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
+#define BTREE_ZERODATA   2    /* Table has keys only - no data */
+#define BTREE_LEAFDATA   4    /* Data stored in leaves only.  Implies INTKEY */
+
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree*, int, int*);
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree*, int);
+SQLITE_PRIVATE int sqlite3BtreeGetMeta(Btree*, int idx, u32 *pValue);
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
+SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree*, int);
+
+struct UnpackedRecord;  /* Forward declaration.  Definition in vdbeaux.c. */
+
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree*,                              /* BTree containing table to open */
+  int iTable,                          /* Index of root page */
+  int wrFlag,                          /* 1 for writing.  0 for read-only */
+  struct KeyInfo*,                     /* First argument to compare function */
+  BtCursor *pCursor                    /* Space to write cursor structure */
+);
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
+
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeMoveto(
+  BtCursor*,
+  const void *pKey,
+  struct UnpackedRecord *pUnKey,
+  i64 nKey,
+  int bias,
+  int *pRes
+);
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
+                                  const void *pData, int nData,
+                                  int nZero, int bias);
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeFlags(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeKeySize(BtCursor*, i64 *pSize);
+SQLITE_PRIVATE int sqlite3BtreeKey(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE sqlite3 *sqlite3BtreeCursorDb(const BtCursor*);
+SQLITE_PRIVATE const void *sqlite3BtreeKeyFetch(BtCursor*, int *pAmt);
+SQLITE_PRIVATE const void *sqlite3BtreeDataFetch(BtCursor*, int *pAmt);
+SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor*, u32 *pSize);
+SQLITE_PRIVATE int sqlite3BtreeData(BtCursor*, u32 offset, u32 amt, void*);
+
+SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*);
+SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);
+
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *);
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3BtreeCursorInfo(BtCursor*, int*, int);
+SQLITE_PRIVATE void sqlite3BtreeCursorList(Btree*);
+SQLITE_PRIVATE int sqlite3BtreePageDump(Btree*, int, int recursive);
+#endif
+
+/*
+** If we are not using shared cache, then there is no need to
+** use mutexes to access the BtShared structures.  So make the
+** Enter and Leave procedures no-ops.
+*/
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+SQLITE_PRIVATE   void sqlite3BtreeEnter(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeLeave(Btree*);
+SQLITE_PRIVATE   int sqlite3BtreeHoldsMutex(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterCursor(BtCursor*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveCursor(BtCursor*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterAll(sqlite3*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveAll(sqlite3*);
+SQLITE_PRIVATE   int sqlite3BtreeHoldsAllMutexes(sqlite3*);
+SQLITE_PRIVATE   void sqlite3BtreeMutexArrayEnter(BtreeMutexArray*);
+SQLITE_PRIVATE   void sqlite3BtreeMutexArrayLeave(BtreeMutexArray*);
+SQLITE_PRIVATE   void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);
+#else
+# define sqlite3BtreeEnter(X)
+# define sqlite3BtreeLeave(X)
+# define sqlite3BtreeHoldsMutex(X) 1
+# define sqlite3BtreeEnterCursor(X)
+# define sqlite3BtreeLeaveCursor(X)
+# define sqlite3BtreeEnterAll(X)
+# define sqlite3BtreeLeaveAll(X)
+# define sqlite3BtreeHoldsAllMutexes(X) 1
+# define sqlite3BtreeMutexArrayEnter(X)
+# define sqlite3BtreeMutexArrayLeave(X)
+# define sqlite3BtreeMutexArrayInsert(X,Y)
+#endif
+
+
+#endif /* _BTREE_H_ */
+
+/************** End of btree.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include vdbe.h in the middle of sqliteInt.h ******************/
+/************** Begin file vdbe.h ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Header file for the Virtual DataBase Engine (VDBE)
+**
+** This header defines the interface to the virtual database engine
+** or VDBE.  The VDBE implements an abstract machine that runs a
+** simple program to access and modify the underlying database.
+**
+** $Id: vdbe.h,v 1.131 2008/05/01 17:03:49 drh Exp $
+*/
+#ifndef _SQLITE_VDBE_H_
+#define _SQLITE_VDBE_H_
+
+/*
+** A single VDBE is an opaque structure named "Vdbe".  Only routines
+** in the source file sqliteVdbe.c are allowed to see the insides
+** of this structure.
+*/
+typedef struct Vdbe Vdbe;
+
+/*
+** The names of the following types declared in vdbeInt.h are required
+** for the VdbeOp definition.
+*/
+typedef struct VdbeFunc VdbeFunc;
+typedef struct Mem Mem;
+typedef struct UnpackedRecord UnpackedRecord;
+
+/*
+** A single instruction of the virtual machine has an opcode
+** and as many as three operands.  The instruction is recorded
+** as an instance of the following structure:
+*/
+struct VdbeOp {
+  u8 opcode;          /* What operation to perform */
+  signed char p4type; /* One of the P4_xxx constants for p4 */
+  u8 opflags;         /* Not currently used */
+  u8 p5;              /* Fifth parameter is an unsigned character */
+  int p1;             /* First operand */
+  int p2;             /* Second parameter (often the jump destination) */
+  int p3;             /* The third parameter */
+  union {             /* forth parameter */
+    int i;                 /* Integer value if p4type==P4_INT32 */
+    void *p;               /* Generic pointer */
+    char *z;               /* Pointer to data for string (char array) types */
+    i64 *pI64;             /* Used when p4type is P4_INT64 */
+    double *pReal;         /* Used when p4type is P4_REAL */
+    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
+    VdbeFunc *pVdbeFunc;   /* Used when p4type is P4_VDBEFUNC */
+    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
+    Mem *pMem;             /* Used when p4type is P4_MEM */
+    sqlite3_vtab *pVtab;   /* Used when p4type is P4_VTAB */
+    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
+  } p4;
+#ifdef SQLITE_DEBUG
+  char *zComment;     /* Comment to improve readability */
+#endif
+#ifdef VDBE_PROFILE
+  int cnt;            /* Number of times this instruction was executed */
+  long long cycles;   /* Total time spend executing this instruction */
+#endif
+};
+typedef struct VdbeOp VdbeOp;
+
+/*
+** A smaller version of VdbeOp used for the VdbeAddOpList() function because
+** it takes up less space.
+*/
+struct VdbeOpList {
+  u8 opcode;          /* What operation to perform */
+  signed char p1;     /* First operand */
+  signed char p2;     /* Second parameter (often the jump destination) */
+  signed char p3;     /* Third parameter */
+};
+typedef struct VdbeOpList VdbeOpList;
+
+/*
+** Allowed values of VdbeOp.p3type
+*/
+#define P4_NOTUSED    0   /* The P4 parameter is not used */
+#define P4_DYNAMIC  (-1)  /* Pointer to a string obtained from sqliteMalloc() */
+#define P4_STATIC   (-2)  /* Pointer to a static string */
+#define P4_COLLSEQ  (-4)  /* P4 is a pointer to a CollSeq structure */
+#define P4_FUNCDEF  (-5)  /* P4 is a pointer to a FuncDef structure */
+#define P4_KEYINFO  (-6)  /* P4 is a pointer to a KeyInfo structure */
+#define P4_VDBEFUNC (-7)  /* P4 is a pointer to a VdbeFunc structure */
+#define P4_MEM      (-8)  /* P4 is a pointer to a Mem*    structure */
+#define P4_TRANSIENT (-9) /* P4 is a pointer to a transient string */
+#define P4_VTAB     (-10) /* P4 is a pointer to an sqlite3_vtab structure */
+#define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
+#define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
+#define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
+#define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
+
+/* When adding a P4 argument using P4_KEYINFO, a copy of the KeyInfo structure
+** is made.  That copy is freed when the Vdbe is finalized.  But if the
+** argument is P4_KEYINFO_HANDOFF, the passed in pointer is used.  It still
+** gets freed when the Vdbe is finalized so it still should be obtained
+** from a single sqliteMalloc().  But no copy is made and the calling
+** function should *not* try to free the KeyInfo.
+*/
+#define P4_KEYINFO_HANDOFF (-9)
+
+/*
+** The Vdbe.aColName array contains 5n Mem structures, where n is the 
+** number of columns of data returned by the statement.
+*/
+#define COLNAME_NAME     0
+#define COLNAME_DECLTYPE 1
+#define COLNAME_DATABASE 2
+#define COLNAME_TABLE    3
+#define COLNAME_COLUMN   4
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+# define COLNAME_N        5      /* Number of COLNAME_xxx symbols */
+#else
+# ifdef SQLITE_OMIT_DECLTYPE
+#   define COLNAME_N      1      /* Store only the name */
+# else
+#   define COLNAME_N      2      /* Store the name and decltype */
+# endif
+#endif
+
+/*
+** The following macro converts a relative address in the p2 field
+** of a VdbeOp structure into a negative number so that 
+** sqlite3VdbeAddOpList() knows that the address is relative.  Calling
+** the macro again restores the address.
+*/
+#define ADDR(X)  (-1-(X))
+
+/*
+** The makefile scans the vdbe.c source file and creates the "opcodes.h"
+** header file that defines a number for each opcode used by the VDBE.
+*/
+/************** Include opcodes.h in the middle of vdbe.h ********************/
+/************** Begin file opcodes.h *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the mkopcodeh.awk script for details */
+#define OP_VNext                                1
+#define OP_Affinity                             2
+#define OP_Column                               3
+#define OP_SetCookie                            4
+#define OP_Real                               125   /* same as TK_FLOAT    */
+#define OP_Sequence                             5
+#define OP_MoveGt                               6
+#define OP_Ge                                  72   /* same as TK_GE       */
+#define OP_RowKey                               7
+#define OP_SCopy                                8
+#define OP_Eq                                  68   /* same as TK_EQ       */
+#define OP_OpenWrite                            9
+#define OP_NotNull                             66   /* same as TK_NOTNULL  */
+#define OP_If                                  10
+#define OP_ToInt                              141   /* same as TK_TO_INT   */
+#define OP_String8                             88   /* same as TK_STRING   */
+#define OP_VRowid                              11
+#define OP_CollSeq                             12
+#define OP_OpenRead                            13
+#define OP_Expire                              14
+#define OP_AutoCommit                          15
+#define OP_Gt                                  69   /* same as TK_GT       */
+#define OP_IntegrityCk                         17
+#define OP_Sort                                18
+#define OP_Copy                                19
+#define OP_Trace                               20
+#define OP_Function                            21
+#define OP_IfNeg                               22
+#define OP_And                                 61   /* same as TK_AND      */
+#define OP_Subtract                            79   /* same as TK_MINUS    */
+#define OP_Noop                                23
+#define OP_Return                              24
+#define OP_Remainder                           82   /* same as TK_REM      */
+#define OP_NewRowid                            25
+#define OP_Multiply                            80   /* same as TK_STAR     */
+#define OP_Variable                            26
+#define OP_String                              27
+#define OP_RealAffinity                        28
+#define OP_VRename                             29
+#define OP_ParseSchema                         30
+#define OP_VOpen                               31
+#define OP_Close                               32
+#define OP_CreateIndex                         33
+#define OP_IsUnique                            34
+#define OP_NotFound                            35
+#define OP_Int64                               36
+#define OP_MustBeInt                           37
+#define OP_Halt                                38
+#define OP_Rowid                               39
+#define OP_IdxLT                               40
+#define OP_AddImm                              41
+#define OP_Statement                           42
+#define OP_RowData                             43
+#define OP_MemMax                              44
+#define OP_Or                                  60   /* same as TK_OR       */
+#define OP_NotExists                           45
+#define OP_Gosub                               46
+#define OP_Divide                              81   /* same as TK_SLASH    */
+#define OP_Integer                             47
+#define OP_ToNumeric                          140   /* same as TK_TO_NUMERIC*/
+#define OP_Prev                                48
+#define OP_Concat                              83   /* same as TK_CONCAT   */
+#define OP_BitAnd                              74   /* same as TK_BITAND   */
+#define OP_VColumn                             49
+#define OP_CreateTable                         50
+#define OP_Last                                51
+#define OP_IsNull                              65   /* same as TK_ISNULL   */
+#define OP_IncrVacuum                          52
+#define OP_IdxRowid                            53
+#define OP_ShiftRight                          77   /* same as TK_RSHIFT   */
+#define OP_ResetCount                          54
+#define OP_FifoWrite                           55
+#define OP_ContextPush                         56
+#define OP_DropTrigger                         57
+#define OP_DropIndex                           58
+#define OP_IdxGE                               59
+#define OP_IdxDelete                           62
+#define OP_Vacuum                              63
+#define OP_MoveLe                              64
+#define OP_IfNot                               73
+#define OP_DropTable                           84
+#define OP_MakeRecord                          85
+#define OP_ToBlob                             139   /* same as TK_TO_BLOB  */
+#define OP_ResultRow                           86
+#define OP_Delete                              89
+#define OP_AggFinal                            90
+#define OP_ShiftLeft                           76   /* same as TK_LSHIFT   */
+#define OP_Goto                                91
+#define OP_TableLock                           92
+#define OP_FifoRead                            93
+#define OP_Clear                               94
+#define OP_MoveLt                              95
+#define OP_Le                                  70   /* same as TK_LE       */
+#define OP_VerifyCookie                        96
+#define OP_AggStep                             97
+#define OP_ToText                             138   /* same as TK_TO_TEXT  */
+#define OP_Not                                 16   /* same as TK_NOT      */
+#define OP_ToReal                             142   /* same as TK_TO_REAL  */
+#define OP_SetNumColumns                       98
+#define OP_Transaction                         99
+#define OP_VFilter                            100
+#define OP_Ne                                  67   /* same as TK_NE       */
+#define OP_VDestroy                           101
+#define OP_ContextPop                         102
+#define OP_BitOr                               75   /* same as TK_BITOR    */
+#define OP_Next                               103
+#define OP_IdxInsert                          104
+#define OP_Lt                                  71   /* same as TK_LT       */
+#define OP_Insert                             105
+#define OP_Destroy                            106
+#define OP_ReadCookie                         107
+#define OP_ForceInt                           108
+#define OP_LoadAnalysis                       109
+#define OP_Explain                            110
+#define OP_OpenPseudo                         111
+#define OP_OpenEphemeral                      112
+#define OP_Null                               113
+#define OP_Move                               114
+#define OP_Blob                               115
+#define OP_Add                                 78   /* same as TK_PLUS     */
+#define OP_Rewind                             116
+#define OP_MoveGe                             117
+#define OP_VBegin                             118
+#define OP_VUpdate                            119
+#define OP_IfZero                             120
+#define OP_BitNot                              87   /* same as TK_BITNOT   */
+#define OP_VCreate                            121
+#define OP_Found                              122
+#define OP_IfPos                              123
+#define OP_NullRow                            124
+
+/* The following opcode values are never used */
+#define OP_NotUsed_126                        126
+#define OP_NotUsed_127                        127
+#define OP_NotUsed_128                        128
+#define OP_NotUsed_129                        129
+#define OP_NotUsed_130                        130
+#define OP_NotUsed_131                        131
+#define OP_NotUsed_132                        132
+#define OP_NotUsed_133                        133
+#define OP_NotUsed_134                        134
+#define OP_NotUsed_135                        135
+#define OP_NotUsed_136                        136
+#define OP_NotUsed_137                        137
+
+
+/* Properties such as "out2" or "jump" that are specified in
+** comments following the "case" for each opcode in the vdbe.c
+** are encoded into bitvectors as follows:
+*/
+#define OPFLG_JUMP            0x0001  /* jump:  P2 holds jmp target */
+#define OPFLG_OUT2_PRERELEASE 0x0002  /* out2-prerelease: */
+#define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
+#define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
+#define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
+#define OPFLG_OUT3            0x0020  /* out3:  P3 is an output */
+#define OPFLG_INITIALIZER {\
+/*   0 */ 0x00, 0x01, 0x00, 0x00, 0x10, 0x02, 0x11, 0x00,\
+/*   8 */ 0x00, 0x00, 0x05, 0x02, 0x00, 0x00, 0x00, 0x00,\
+/*  16 */ 0x04, 0x00, 0x01, 0x00, 0x00, 0x00, 0x05, 0x00,\
+/*  24 */ 0x00, 0x02, 0x02, 0x02, 0x04, 0x00, 0x00, 0x00,\
+/*  32 */ 0x00, 0x02, 0x11, 0x11, 0x02, 0x05, 0x00, 0x02,\
+/*  40 */ 0x11, 0x04, 0x00, 0x00, 0x0c, 0x11, 0x01, 0x02,\
+/*  48 */ 0x01, 0x00, 0x02, 0x01, 0x01, 0x02, 0x00, 0x04,\
+/*  56 */ 0x00, 0x00, 0x00, 0x11, 0x2c, 0x2c, 0x00, 0x00,\
+/*  64 */ 0x11, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
+/*  72 */ 0x15, 0x05, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c,\
+/*  80 */ 0x2c, 0x2c, 0x2c, 0x2c, 0x00, 0x00, 0x00, 0x04,\
+/*  88 */ 0x02, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x11,\
+/*  96 */ 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x01,\
+/* 104 */ 0x08, 0x00, 0x02, 0x02, 0x05, 0x00, 0x00, 0x00,\
+/* 112 */ 0x00, 0x02, 0x00, 0x02, 0x01, 0x11, 0x00, 0x00,\
+/* 120 */ 0x05, 0x00, 0x11, 0x05, 0x00, 0x02, 0x00, 0x00,\
+/* 128 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/* 136 */ 0x00, 0x00, 0x04, 0x04, 0x04, 0x04, 0x04,}
+
+/************** End of opcodes.h *********************************************/
+/************** Continuing where we left off in vdbe.h ***********************/
+
+/*
+** Prototypes for the VDBE interface.  See comments on the implementation
+** for a description of what each of these routines does.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(sqlite3*);
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe*,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe*, int addr);
+SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe*, int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe*, int);
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbeTrace(Vdbe*,FILE*);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe*, int);
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, int);
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe*);
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe*,Vdbe*);
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+SQLITE_PRIVATE int sqlite3VdbeReleaseMemory(int);
+#endif
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,void*,int);
+SQLITE_PRIVATE void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
+
+
+#ifndef NDEBUG
+SQLITE_PRIVATE   void sqlite3VdbeComment(Vdbe*, const char*, ...);
+# define VdbeComment(X)  sqlite3VdbeComment X
+#else
+# define VdbeComment(X)
+#endif
+
+#endif
+
+/************** End of vdbe.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include pager.h in the middle of sqliteInt.h *****************/
+/************** Begin file pager.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.  The page cache subsystem reads and writes a file a page
+** at a time and provides a journal for rollback.
+**
+** @(#) $Id: pager.h,v 1.72 2008/05/01 17:03:49 drh Exp $
+*/
+
+#ifndef _PAGER_H_
+#define _PAGER_H_
+
+/*
+** The type used to represent a page number.  The first page in a file
+** is called page 1.  0 is used to represent "not a page".
+*/
+typedef unsigned int Pgno;
+
+/*
+** Each open file is managed by a separate instance of the "Pager" structure.
+*/
+typedef struct Pager Pager;
+
+/*
+** Handle type for pages.
+*/
+typedef struct PgHdr DbPage;
+
+/*
+** Allowed values for the flags parameter to sqlite3PagerOpen().
+**
+** NOTE: This values must match the corresponding BTREE_ values in btree.h.
+*/
+#define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
+#define PAGER_NO_READLOCK   0x0002    /* Omit readlocks on readonly files */
+
+/*
+** Valid values for the second argument to sqlite3PagerLockingMode().
+*/
+#define PAGER_LOCKINGMODE_QUERY      -1
+#define PAGER_LOCKINGMODE_NORMAL      0
+#define PAGER_LOCKINGMODE_EXCLUSIVE   1
+
+/*
+** Valid values for the second argument to sqlite3PagerJournalMode().
+*/
+#define PAGER_JOURNALMODE_QUERY      -1
+#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
+#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
+#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
+
+/*
+** See source code comments for a detailed description of the following
+** routines:
+*/
+SQLITE_PRIVATE int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, int,int,int);
+SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager*, BusyHandler *pBusyHandler);
+SQLITE_PRIVATE void sqlite3PagerSetDestructor(Pager*, void(*)(DbPage*,int));
+SQLITE_PRIVATE void sqlite3PagerSetReiniter(Pager*, void(*)(DbPage*,int));
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u16*);
+SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager*, int);
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
+#define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0)
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
+SQLITE_PRIVATE int sqlite3PagerRef(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerUnref(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerWrite(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerPagecount(Pager*);
+SQLITE_PRIVATE int sqlite3PagerTruncate(Pager*,Pgno);
+SQLITE_PRIVATE int sqlite3PagerBegin(DbPage*, int exFlag);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, Pgno, int);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager*);
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager*);
+SQLITE_PRIVATE int sqlite3PagerIsreadonly(Pager*);
+SQLITE_PRIVATE int sqlite3PagerStmtBegin(Pager*);
+SQLITE_PRIVATE int sqlite3PagerStmtCommit(Pager*);
+SQLITE_PRIVATE int sqlite3PagerStmtRollback(Pager*);
+SQLITE_PRIVATE void sqlite3PagerDontRollback(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerDontWrite(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerRefcount(Pager*);
+SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager*,int,int);
+SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager*);
+SQLITE_PRIVATE const sqlite3_vfs *sqlite3PagerVfs(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerDirname(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager*);
+SQLITE_PRIVATE int sqlite3PagerNosync(Pager*);
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager*,DbPage*,Pgno);
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *); 
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *); 
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerJournalMode(Pager *, int);
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager*);
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager);
+
+#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
+SQLITE_PRIVATE   int sqlite3PagerReleaseMemory(int);
+#endif
+
+#ifdef SQLITE_HAS_CODEC
+SQLITE_PRIVATE   void sqlite3PagerSetCodec(Pager*,void*(*)(void*,void*,Pgno,int),void*);
+#endif
+
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+SQLITE_PRIVATE   Pgno sqlite3PagerPagenumber(DbPage*);
+SQLITE_PRIVATE   int sqlite3PagerIswriteable(DbPage*);
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int *sqlite3PagerStats(Pager*);
+SQLITE_PRIVATE   void sqlite3PagerRefdump(Pager*);
+#endif
+
+#ifdef SQLITE_TEST
+void disable_simulated_io_errors(void);
+void enable_simulated_io_errors(void);
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+#endif /* _PAGER_H_ */
+
+/************** End of pager.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/************** Include os.h in the middle of sqliteInt.h ********************/
+/************** Begin file os.h **********************************************/
+/*
+** 2001 September 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file (together with is companion C source-code file
+** "os.c") attempt to abstract the underlying operating system so that
+** the SQLite library will work on both POSIX and windows systems.
+**
+** This header file is #include-ed by sqliteInt.h and thus ends up
+** being included by every source file.
+*/
+#ifndef _SQLITE_OS_H_
+#define _SQLITE_OS_H_
+
+/*
+** Figure out if we are dealing with Unix, Windows, or some other
+** operating system.  After the following block of preprocess macros,
+** all of OS_UNIX, OS_WIN, OS_OS2, and OS_OTHER will defined to either
+** 1 or 0.  One of the four will be 1.  The other three will be 0.
+*/
+#if defined(OS_OTHER)
+# if OS_OTHER==1
+#   undef OS_UNIX
+#   define OS_UNIX 0
+#   undef OS_WIN
+#   define OS_WIN 0
+#   undef OS_OS2
+#   define OS_OS2 0
+# else
+#   undef OS_OTHER
+# endif
+#endif
+#if !defined(OS_UNIX) && !defined(OS_OTHER)
+# define OS_OTHER 0
+# ifndef OS_WIN
+#   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
+#     define OS_WIN 1
+#     define OS_UNIX 0
+#     define OS_OS2 0
+#   elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__)
+#     define OS_WIN 0
+#     define OS_UNIX 0
+#     define OS_OS2 1
+#   else
+#     define OS_WIN 0
+#     define OS_UNIX 1
+#     define OS_OS2 0
+#  endif
+# else
+#  define OS_UNIX 0
+#  define OS_OS2 0
+# endif
+#else
+# ifndef OS_WIN
+#  define OS_WIN 0
+# endif
+#endif
+
+
+
+/*
+** Define the maximum size of a temporary filename
+*/
+#if OS_WIN
+# include <windows.h>
+# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)
+#elif OS_OS2
+# if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_MEMORY)
+#  include <os2safe.h> /* has to be included before os2.h for linking to work */
+# endif
+# define INCL_DOSDATETIME
+# define INCL_DOSFILEMGR
+# define INCL_DOSERRORS
+# define INCL_DOSMISC
+# define INCL_DOSPROCESS
+# define INCL_DOSMODULEMGR
+# define INCL_DOSSEMAPHORES
+# include <os2.h>
+# include <uconv.h>
+# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)
+#else
+# define SQLITE_TEMPNAME_SIZE 200
+#endif
+
+/* If the SET_FULLSYNC macro is not defined above, then make it
+** a no-op
+*/
+#ifndef SET_FULLSYNC
+# define SET_FULLSYNC(x,y)
+#endif
+
+/*
+** The default size of a disk sector
+*/
+#ifndef SQLITE_DEFAULT_SECTOR_SIZE
+# define SQLITE_DEFAULT_SECTOR_SIZE 512
+#endif
+
+/*
+** Temporary files are named starting with this prefix followed by 16 random
+** alphanumeric characters, and no file extension. They are stored in the
+** OS's standard temporary file directory, and are deleted prior to exit.
+** If sqlite is being embedded in another program, you may wish to change the
+** prefix to reflect your program's name, so that if your program exits
+** prematurely, old temporary files can be easily identified. This can be done
+** using -DSQLITE_TEMP_FILE_PREFIX=myprefix_ on the compiler command line.
+**
+** 2006-10-31:  The default prefix used to be "sqlite_".  But then
+** Mcafee started using SQLite in their anti-virus product and it
+** started putting files with the "sqlite" name in the c:/temp folder.
+** This annoyed many windows users.  Those users would then do a 
+** Google search for "sqlite", find the telephone numbers of the
+** developers and call to wake them up at night and complain.
+** For this reason, the default name prefix is changed to be "sqlite" 
+** spelled backwards.  So the temp files are still identified, but
+** anybody smart enough to figure out the code is also likely smart
+** enough to know that calling the developer will not help get rid
+** of the file.
+*/
+#ifndef SQLITE_TEMP_FILE_PREFIX
+# define SQLITE_TEMP_FILE_PREFIX "etilqs_"
+#endif
+
+/*
+** The following values may be passed as the second argument to
+** sqlite3OsLock(). The various locks exhibit the following semantics:
+**
+** SHARED:    Any number of processes may hold a SHARED lock simultaneously.
+** RESERVED:  A single process may hold a RESERVED lock on a file at
+**            any time. Other processes may hold and obtain new SHARED locks.
+** PENDING:   A single process may hold a PENDING lock on a file at
+**            any one time. Existing SHARED locks may persist, but no new
+**            SHARED locks may be obtained by other processes.
+** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks.
+**
+** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a
+** process that requests an EXCLUSIVE lock may actually obtain a PENDING
+** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to
+** sqlite3OsLock().
+*/
+#define NO_LOCK         0
+#define SHARED_LOCK     1
+#define RESERVED_LOCK   2
+#define PENDING_LOCK    3
+#define EXCLUSIVE_LOCK  4
+
+/*
+** File Locking Notes:  (Mostly about windows but also some info for Unix)
+**
+** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because
+** those functions are not available.  So we use only LockFile() and
+** UnlockFile().
+**
+** LockFile() prevents not just writing but also reading by other processes.
+** A SHARED_LOCK is obtained by locking a single randomly-chosen 
+** byte out of a specific range of bytes. The lock byte is obtained at 
+** random so two separate readers can probably access the file at the 
+** same time, unless they are unlucky and choose the same lock byte.
+** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range.
+** There can only be one writer.  A RESERVED_LOCK is obtained by locking
+** a single byte of the file that is designated as the reserved lock byte.
+** A PENDING_LOCK is obtained by locking a designated byte different from
+** the RESERVED_LOCK byte.
+**
+** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,
+** which means we can use reader/writer locks.  When reader/writer locks
+** are used, the lock is placed on the same range of bytes that is used
+** for probabilistic locking in Win95/98/ME.  Hence, the locking scheme
+** will support two or more Win95 readers or two or more WinNT readers.
+** But a single Win95 reader will lock out all WinNT readers and a single
+** WinNT reader will lock out all other Win95 readers.
+**
+** The following #defines specify the range of bytes used for locking.
+** SHARED_SIZE is the number of bytes available in the pool from which
+** a random byte is selected for a shared lock.  The pool of bytes for
+** shared locks begins at SHARED_FIRST. 
+**
+** These #defines are available in sqlite_aux.h so that adaptors for
+** connecting SQLite to other operating systems can use the same byte
+** ranges for locking.  In particular, the same locking strategy and
+** byte ranges are used for Unix.  This leaves open the possiblity of having
+** clients on win95, winNT, and unix all talking to the same shared file
+** and all locking correctly.  To do so would require that samba (or whatever
+** tool is being used for file sharing) implements locks correctly between
+** windows and unix.  I'm guessing that isn't likely to happen, but by
+** using the same locking range we are at least open to the possibility.
+**
+** Locking in windows is manditory.  For this reason, we cannot store
+** actual data in the bytes used for locking.  The pager never allocates
+** the pages involved in locking therefore.  SHARED_SIZE is selected so
+** that all locks will fit on a single page even at the minimum page size.
+** PENDING_BYTE defines the beginning of the locks.  By default PENDING_BYTE
+** is set high so that we don't have to allocate an unused page except
+** for very large databases.  But one should test the page skipping logic 
+** by setting PENDING_BYTE low and running the entire regression suite.
+**
+** Changing the value of PENDING_BYTE results in a subtly incompatible
+** file format.  Depending on how it is changed, you might not notice
+** the incompatibility right away, even running a full regression test.
+** The default location of PENDING_BYTE is the first byte past the
+** 1GB boundary.
+**
+*/
+#ifndef SQLITE_TEST
+#define PENDING_BYTE      0x40000000  /* First byte past the 1GB boundary */
+#else
+SQLITE_API extern unsigned int sqlite3_pending_byte;
+#define PENDING_BYTE sqlite3_pending_byte
+#endif
+
+#define RESERVED_BYTE     (PENDING_BYTE+1)
+#define SHARED_FIRST      (PENDING_BYTE+2)
+#define SHARED_SIZE       510
+
+/* 
+** Functions for accessing sqlite3_file methods 
+*/
+SQLITE_PRIVATE int sqlite3OsClose(sqlite3_file*);
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file*, void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file*, const void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file*, i64 size);
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file*,int,void*);
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
+
+/* 
+** Functions for accessing sqlite3_vfs methods 
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
+SQLITE_PRIVATE int sqlite3OsAccess(sqlite3_vfs *, const char *, int);
+SQLITE_PRIVATE int sqlite3OsGetTempname(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *);
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE void *sqlite3OsDlSym(sqlite3_vfs *, void *, const char *);
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *, void *);
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *, int);
+SQLITE_PRIVATE int sqlite3OsCurrentTime(sqlite3_vfs *, double*);
+
+/*
+** Convenience functions for opening and closing files using 
+** sqlite3_malloc() to obtain space for the file-handle structure.
+*/
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*);
+SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *);
+
+/*
+** Each OS-specific backend defines an instance of the following
+** structure for returning a pointer to its sqlite3_vfs.  If OS_OTHER
+** is defined (meaning that the application-defined OS interface layer
+** is used) then there is no default VFS.   The application must
+** register one or more VFS structures using sqlite3_vfs_register()
+** before attempting to use SQLite.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3OsDefaultVfs(void);
+
+#endif /* _SQLITE_OS_H_ */
+
+/************** End of os.h **************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include mutex.h in the middle of sqliteInt.h *****************/
+/************** Begin file mutex.h *******************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the common header for all mutex implementations.
+** The sqliteInt.h header #includes this file so that it is available
+** to all source files.  We break it out in an effort to keep the code
+** better organized.
+**
+** NOTE:  source files should *not* #include this header file directly.
+** Source files should #include the sqliteInt.h file and let that file
+** include this one indirectly.
+**
+** $Id: mutex.h,v 1.2 2007/08/30 14:10:30 drh Exp $
+*/
+
+
+#ifdef SQLITE_MUTEX_APPDEF
+/*
+** If SQLITE_MUTEX_APPDEF is defined, then this whole module is
+** omitted and equivalent functionality must be provided by the
+** application that links against the SQLite library.
+*/
+#else
+/*
+** Figure out what version of the code to use.  The choices are
+**
+**   SQLITE_MUTEX_NOOP         For single-threaded applications that
+**                             do not desire error checking.
+**
+**   SQLITE_MUTEX_NOOP_DEBUG   For single-threaded applications with
+**                             error checking to help verify that mutexes
+**                             are being used correctly even though they
+**                             are not needed.  Used when SQLITE_DEBUG is
+**                             defined on single-threaded builds.
+**
+**   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
+**
+**   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
+**
+**   SQLITE_MUTEX_OS2          For multi-threaded applications on OS/2.
+*/
+#define SQLITE_MUTEX_NOOP 1   /* The default */
+#if defined(SQLITE_DEBUG) && !SQLITE_THREADSAFE
+# undef SQLITE_MUTEX_NOOP
+# define SQLITE_MUTEX_NOOP_DEBUG
+#endif
+#if defined(SQLITE_MUTEX_NOOP) && SQLITE_THREADSAFE && OS_UNIX
+# undef SQLITE_MUTEX_NOOP
+# define SQLITE_MUTEX_PTHREADS
+#endif
+#if defined(SQLITE_MUTEX_NOOP) && SQLITE_THREADSAFE && OS_WIN
+# undef SQLITE_MUTEX_NOOP
+# define SQLITE_MUTEX_W32
+#endif
+#if defined(SQLITE_MUTEX_NOOP) && SQLITE_THREADSAFE && OS_OS2
+# undef SQLITE_MUTEX_NOOP
+# define SQLITE_MUTEX_OS2
+#endif
+
+#ifdef SQLITE_MUTEX_NOOP
+/*
+** If this is a no-op implementation, implement everything as macros.
+*/
+#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
+#define sqlite3_mutex_free(X)
+#define sqlite3_mutex_enter(X)
+#define sqlite3_mutex_try(X)      SQLITE_OK
+#define sqlite3_mutex_leave(X)
+#define sqlite3_mutex_held(X)     1
+#define sqlite3_mutex_notheld(X)  1
+#endif
+
+#endif /* SQLITE_MUTEX_APPDEF */
+
+/************** End of mutex.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+
+/*
+** Each database file to be accessed by the system is an instance
+** of the following structure.  There are normally two of these structures
+** in the sqlite.aDb[] array.  aDb[0] is the main database file and
+** aDb[1] is the database file used to hold temporary tables.  Additional
+** databases may be attached.
+*/
+struct Db {
+  char *zName;         /* Name of this database */
+  Btree *pBt;          /* The B*Tree structure for this database file */
+  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
+  u8 safety_level;     /* How aggressive at synching data to disk */
+  void *pAux;               /* Auxiliary data.  Usually NULL */
+  void (*xFreeAux)(void*);  /* Routine to free pAux */
+  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
+};
+
+/*
+** An instance of the following structure stores a database schema.
+**
+** If there are no virtual tables configured in this schema, the
+** Schema.db variable is set to NULL. After the first virtual table
+** has been added, it is set to point to the database connection 
+** used to create the connection. Once a virtual table has been
+** added to the Schema structure and the Schema.db variable populated, 
+** only that database connection may use the Schema to prepare 
+** statements.
+*/
+struct Schema {
+  int schema_cookie;   /* Database schema version number for this file */
+  Hash tblHash;        /* All tables indexed by name */
+  Hash idxHash;        /* All (named) indices indexed by name */
+  Hash trigHash;       /* All triggers indexed by name */
+  Hash aFKey;          /* Foreign keys indexed by to-table */
+  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
+  u8 file_format;      /* Schema format version for this file */
+  u8 enc;              /* Text encoding used by this database */
+  u16 flags;           /* Flags associated with this schema */
+  int cache_size;      /* Number of pages to use in the cache */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3 *db;         /* "Owner" connection. See comment above */
+#endif
+};
+
+/*
+** These macros can be used to test, set, or clear bits in the 
+** Db.flags field.
+*/
+#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))
+#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)
+#define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->flags|=(P)
+#define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)
+
+/*
+** Allowed values for the DB.flags field.
+**
+** The DB_SchemaLoaded flag is set after the database schema has been
+** read into internal hash tables.
+**
+** DB_UnresetViews means that one or more views have column names that
+** have been filled out.  If the schema changes, these column names might
+** changes and so the view will need to be reset.
+*/
+#define DB_SchemaLoaded    0x0001  /* The schema has been loaded */
+#define DB_UnresetViews    0x0002  /* Some views have defined column names */
+#define DB_Empty           0x0004  /* The file is empty (length 0 bytes) */
+
+/*
+** The number of different kinds of things that can be limited
+** using the sqlite3_limit() interface.
+*/
+#define SQLITE_N_LIMIT (SQLITE_LIMIT_VARIABLE_NUMBER+1)
+
+/*
+** Each database is an instance of the following structure.
+**
+** The sqlite.lastRowid records the last insert rowid generated by an
+** insert statement.  Inserts on views do not affect its value.  Each
+** trigger has its own context, so that lastRowid can be updated inside
+** triggers as usual.  The previous value will be restored once the trigger
+** exits.  Upon entering a before or instead of trigger, lastRowid is no
+** longer (since after version 2.8.12) reset to -1.
+**
+** The sqlite.nChange does not count changes within triggers and keeps no
+** context.  It is reset at start of sqlite3_exec.
+** The sqlite.lsChange represents the number of changes made by the last
+** insert, update, or delete statement.  It remains constant throughout the
+** length of a statement and is then updated by OP_SetCounts.  It keeps a
+** context stack just like lastRowid so that the count of changes
+** within a trigger is not seen outside the trigger.  Changes to views do not
+** affect the value of lsChange.
+** The sqlite.csChange keeps track of the number of current changes (since
+** the last statement) and is used to update sqlite_lsChange.
+**
+** The member variables sqlite.errCode, sqlite.zErrMsg and sqlite.zErrMsg16
+** store the most recent error code and, if applicable, string. The
+** internal function sqlite3Error() is used to set these variables
+** consistently.
+*/
+struct sqlite3 {
+  sqlite3_vfs *pVfs;            /* OS Interface */
+  int nDb;                      /* Number of backends currently in use */
+  Db *aDb;                      /* All backends */
+  int flags;                    /* Miscellanous flags. See below */
+  int openFlags;                /* Flags passed to sqlite3_vfs.xOpen() */
+  int errCode;                  /* Most recent error code (SQLITE_*) */
+  int errMask;                  /* & result codes with this before returning */
+  u8 autoCommit;                /* The auto-commit flag. */
+  u8 temp_store;                /* 1: file 2: memory 0: default */
+  u8 mallocFailed;              /* True if we have seen a malloc failure */
+  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
+  u8 dfltJournalMode;           /* Default journal mode for attached dbs */
+  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
+  int nextPagesize;             /* Pagesize after VACUUM if >0 */
+  int nTable;                   /* Number of tables in the database */
+  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
+  i64 lastRowid;                /* ROWID of most recent insert (see above) */
+  i64 priorNewRowid;            /* Last randomly generated ROWID */
+  int magic;                    /* Magic number for detect library misuse */
+  int nChange;                  /* Value returned by sqlite3_changes() */
+  int nTotalChange;             /* Value returned by sqlite3_total_changes() */
+  sqlite3_mutex *mutex;         /* Connection mutex */
+  int aLimit[SQLITE_N_LIMIT];   /* Limits */
+  struct sqlite3InitInfo {      /* Information used during initialization */
+    int iDb;                    /* When back is being initialized */
+    int newTnum;                /* Rootpage of table being initialized */
+    u8 busy;                    /* TRUE if currently initializing */
+  } init;
+  int nExtension;               /* Number of loaded extensions */
+  void **aExtension;            /* Array of shared libraray handles */
+  struct Vdbe *pVdbe;           /* List of active virtual machines */
+  int activeVdbeCnt;            /* Number of vdbes currently executing */
+  void (*xTrace)(void*,const char*);        /* Trace function */
+  void *pTraceArg;                          /* Argument to the trace function */
+  void (*xProfile)(void*,const char*,u64);  /* Profiling function */
+  void *pProfileArg;                        /* Argument to profile function */
+  void *pCommitArg;                 /* Argument to xCommitCallback() */   
+  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
+  void *pRollbackArg;               /* Argument to xRollbackCallback() */   
+  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
+  void *pUpdateArg;
+  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
+  void *pCollNeededArg;
+  sqlite3_value *pErr;          /* Most recent error message */
+  char *zErrMsg;                /* Most recent error message (UTF-8 encoded) */
+  char *zErrMsg16;              /* Most recent error message (UTF-16 encoded) */
+  union {
+    int isInterrupted;          /* True if sqlite3_interrupt has been called */
+    double notUsed1;            /* Spacer */
+  } u1;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
+                                /* Access authorization function */
+  void *pAuthArg;               /* 1st argument to the access auth function */
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  int (*xProgress)(void *);     /* The progress callback */
+  void *pProgressArg;           /* Argument to the progress callback */
+  int nProgressOps;             /* Number of opcodes for progress callback */
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Hash aModule;                 /* populated by sqlite3_create_module() */
+  Table *pVTab;                 /* vtab with active Connect/Create method */
+  sqlite3_vtab **aVTrans;       /* Virtual tables with open transactions */
+  int nVTrans;                  /* Allocated size of aVTrans */
+#endif
+  Hash aFunc;                   /* All functions that can be in SQL exprs */
+  Hash aCollSeq;                /* All collating sequences */
+  BusyHandler busyHandler;      /* Busy callback */
+  int busyTimeout;              /* Busy handler timeout, in msec */
+  Db aDbStatic[2];              /* Static space for the 2 default backends */
+#ifdef SQLITE_SSE
+  sqlite3_stmt *pFetch;         /* Used by SSE to fetch stored statements */
+#endif
+};
+
+/*
+** A macro to discover the encoding of a database.
+*/
+#define ENC(db) ((db)->aDb[0].pSchema->enc)
+
+/*
+** Possible values for the sqlite.flags and or Db.flags fields.
+**
+** On sqlite.flags, the SQLITE_InTrans value means that we have
+** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement
+** transaction is active on that particular database file.
+*/
+#define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
+#define SQLITE_InTrans        0x00000008  /* True if in a transaction */
+#define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
+#define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
+#define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
+#define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
+                                          /*   DELETE, or UPDATE and return */
+                                          /*   the count using a callback. */
+#define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
+                                          /*   result set is empty */
+#define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */
+#define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */
+#define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */
+#define SQLITE_NoReadlock     0x00001000  /* Readlocks are omitted when 
+                                          ** accessing read-only databases */
+#define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */
+#define SQLITE_ReadUncommitted 0x00004000 /* For shared-cache mode */
+#define SQLITE_LegacyFileFmt  0x00008000  /* Create new databases in format 1 */
+#define SQLITE_FullFSync      0x00010000  /* Use full fsync on the backend */
+#define SQLITE_LoadExtension  0x00020000  /* Enable load_extension */
+
+#define SQLITE_RecoveryMode   0x00040000  /* Ignore schema errors */
+#define SQLITE_SharedCache    0x00080000  /* Cache sharing is enabled */
+#define SQLITE_Vtab           0x00100000  /* There exists a virtual table */
+
+/*
+** Possible values for the sqlite.magic field.
+** The numbers are obtained at random and have no special meaning, other
+** than being distinct from one another.
+*/
+#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
+#define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
+#define SQLITE_MAGIC_SICK     0x4b771290  /* Error and awaiting close */
+#define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
+#define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
+
+/*
+** Each SQL function is defined by an instance of the following
+** structure.  A pointer to this structure is stored in the sqlite.aFunc
+** hash table.  When multiple functions have the same name, the hash table
+** points to a linked list of these structures.
+*/
+struct FuncDef {
+  i16 nArg;            /* Number of arguments.  -1 means unlimited */
+  u8 iPrefEnc;         /* Preferred text encoding (SQLITE_UTF8, 16LE, 16BE) */
+  u8 needCollSeq;      /* True if sqlite3GetFuncCollSeq() might be called */
+  u8 flags;            /* Some combination of SQLITE_FUNC_* */
+  void *pUserData;     /* User data parameter */
+  FuncDef *pNext;      /* Next function with same name */
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */
+  void (*xFinalize)(sqlite3_context*);                /* Aggregate finializer */
+  char zName[1];       /* SQL name of the function.  MUST BE LAST */
+};
+
+/*
+** Each SQLite module (virtual table definition) is defined by an
+** instance of the following structure, stored in the sqlite3.aModule
+** hash table.
+*/
+struct Module {
+  const sqlite3_module *pModule;       /* Callback pointers */
+  const char *zName;                   /* Name passed to create_module() */
+  void *pAux;                          /* pAux passed to create_module() */
+  void (*xDestroy)(void *);            /* Module destructor function */
+};
+
+/*
+** Possible values for FuncDef.flags
+*/
+#define SQLITE_FUNC_LIKE   0x01  /* Candidate for the LIKE optimization */
+#define SQLITE_FUNC_CASE   0x02  /* Case-sensitive LIKE-type function */
+#define SQLITE_FUNC_EPHEM  0x04  /* Ephermeral.  Delete with VDBE */
+
+/*
+** information about each column of an SQL table is held in an instance
+** of this structure.
+*/
+struct Column {
+  char *zName;     /* Name of this column */
+  Expr *pDflt;     /* Default value of this column */
+  char *zType;     /* Data type for this column */
+  char *zColl;     /* Collating sequence.  If NULL, use the default */
+  u8 notNull;      /* True if there is a NOT NULL constraint */
+  u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
+  char affinity;   /* One of the SQLITE_AFF_... values */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  u8 isHidden;     /* True if this column is 'hidden' */
+#endif
+};
+
+/*
+** A "Collating Sequence" is defined by an instance of the following
+** structure. Conceptually, a collating sequence consists of a name and
+** a comparison routine that defines the order of that sequence.
+**
+** There may two seperate implementations of the collation function, one
+** that processes text in UTF-8 encoding (CollSeq.xCmp) and another that
+** processes text encoded in UTF-16 (CollSeq.xCmp16), using the machine
+** native byte order. When a collation sequence is invoked, SQLite selects
+** the version that will require the least expensive encoding
+** translations, if any.
+**
+** The CollSeq.pUser member variable is an extra parameter that passed in
+** as the first argument to the UTF-8 comparison function, xCmp.
+** CollSeq.pUser16 is the equivalent for the UTF-16 comparison function,
+** xCmp16.
+**
+** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
+** collating sequence is undefined.  Indices built on an undefined
+** collating sequence may not be read or written.
+*/
+struct CollSeq {
+  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
+  u8 enc;               /* Text encoding handled by xCmp() */
+  u8 type;              /* One of the SQLITE_COLL_... values below */
+  void *pUser;          /* First argument to xCmp() */
+  int (*xCmp)(void*,int, const void*, int, const void*);
+  void (*xDel)(void*);  /* Destructor for pUser */
+};
+
+/*
+** Allowed values of CollSeq flags:
+*/
+#define SQLITE_COLL_BINARY  1  /* The default memcmp() collating sequence */
+#define SQLITE_COLL_NOCASE  2  /* The built-in NOCASE collating sequence */
+#define SQLITE_COLL_REVERSE 3  /* The built-in REVERSE collating sequence */
+#define SQLITE_COLL_USER    0  /* Any other user-defined collating sequence */
+
+/*
+** A sort order can be either ASC or DESC.
+*/
+#define SQLITE_SO_ASC       0  /* Sort in ascending order */
+#define SQLITE_SO_DESC      1  /* Sort in ascending order */
+
+/*
+** Column affinity types.
+**
+** These used to have mnemonic name like 'i' for SQLITE_AFF_INTEGER and
+** 't' for SQLITE_AFF_TEXT.  But we can save a little space and improve
+** the speed a little by number the values consecutively.  
+**
+** But rather than start with 0 or 1, we begin with 'a'.  That way,
+** when multiple affinity types are concatenated into a string and
+** used as the P4 operand, they will be more readable.
+**
+** Note also that the numeric types are grouped together so that testing
+** for a numeric type is a single comparison.
+*/
+#define SQLITE_AFF_TEXT     'a'
+#define SQLITE_AFF_NONE     'b'
+#define SQLITE_AFF_NUMERIC  'c'
+#define SQLITE_AFF_INTEGER  'd'
+#define SQLITE_AFF_REAL     'e'
+
+#define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)
+
+/*
+** The SQLITE_AFF_MASK values masks off the significant bits of an
+** affinity value. 
+*/
+#define SQLITE_AFF_MASK     0x67
+
+/*
+** Additional bit values that can be ORed with an affinity without
+** changing the affinity.
+*/
+#define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
+#define SQLITE_NULLEQUAL    0x10  /* compare NULLs equal */
+#define SQLITE_STOREP2      0x80  /* Store result in reg[P2] rather than jump */
+
+/*
+** Each SQL table is represented in memory by an instance of the
+** following structure.
+**
+** Table.zName is the name of the table.  The case of the original
+** CREATE TABLE statement is stored, but case is not significant for
+** comparisons.
+**
+** Table.nCol is the number of columns in this table.  Table.aCol is a
+** pointer to an array of Column structures, one for each column.
+**
+** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
+** the column that is that key.   Otherwise Table.iPKey is negative.  Note
+** that the datatype of the PRIMARY KEY must be INTEGER for this field to
+** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
+** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
+** is generated for each row of the table.  Table.hasPrimKey is true if
+** the table has any PRIMARY KEY, INTEGER or otherwise.
+**
+** Table.tnum is the page number for the root BTree page of the table in the
+** database file.  If Table.iDb is the index of the database table backend
+** in sqlite.aDb[].  0 is for the main database and 1 is for the file that
+** holds temporary tables and indices.  If Table.isEphem
+** is true, then the table is stored in a file that is automatically deleted
+** when the VDBE cursor to the table is closed.  In this case Table.tnum 
+** refers VDBE cursor number that holds the table open, not to the root
+** page number.  Transient tables are used to hold the results of a
+** sub-query that appears instead of a real table name in the FROM clause 
+** of a SELECT statement.
+*/
+struct Table {
+  char *zName;     /* Name of the table */
+  int nCol;        /* Number of columns in this table */
+  Column *aCol;    /* Information about each column */
+  int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
+  Index *pIndex;   /* List of SQL indexes on this table. */
+  int tnum;        /* Root BTree node for this table (see note above) */
+  Select *pSelect; /* NULL for tables.  Points to definition if a view. */
+  int nRef;          /* Number of pointers to this Table */
+  Trigger *pTrigger; /* List of SQL triggers on this table */
+  FKey *pFKey;       /* Linked list of all foreign keys in this table */
+  char *zColAff;     /* String defining the affinity of each column */
+#ifndef SQLITE_OMIT_CHECK
+  Expr *pCheck;      /* The AND of all CHECK constraints */
+#endif
+#ifndef SQLITE_OMIT_ALTERTABLE
+  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
+#endif
+  u8 readOnly;     /* True if this table should not be written by the user */
+  u8 isEphem;      /* True if created using OP_OpenEphermeral */
+  u8 hasPrimKey;   /* True if there exists a primary key */
+  u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
+  u8 autoInc;      /* True if the integer primary key is autoincrement */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  u8 isVirtual;             /* True if this is a virtual table */
+  u8 isCommit;              /* True once the CREATE TABLE has been committed */
+  Module *pMod;             /* Pointer to the implementation of the module */
+  sqlite3_vtab *pVtab;      /* Pointer to the module instance */
+  int nModuleArg;           /* Number of arguments to the module */
+  char **azModuleArg;       /* Text of all module args. [0] is module name */
+#endif
+  Schema *pSchema;          /* Schema that contains this table */
+};
+
+/*
+** Test to see whether or not a table is a virtual table.  This is
+** done as a macro so that it will be optimized out when virtual
+** table support is omitted from the build.
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+#  define IsVirtual(X)      ((X)->isVirtual)
+#  define IsHiddenColumn(X) ((X)->isHidden)
+#else
+#  define IsVirtual(X)      0
+#  define IsHiddenColumn(X) 0
+#endif
+
+/*
+** Each foreign key constraint is an instance of the following structure.
+**
+** A foreign key is associated with two tables.  The "from" table is
+** the table that contains the REFERENCES clause that creates the foreign
+** key.  The "to" table is the table that is named in the REFERENCES clause.
+** Consider this example:
+**
+**     CREATE TABLE ex1(
+**       a INTEGER PRIMARY KEY,
+**       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
+**     );
+**
+** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
+**
+** Each REFERENCES clause generates an instance of the following structure
+** which is attached to the from-table.  The to-table need not exist when
+** the from-table is created.  The existance of the to-table is not checked
+** until an attempt is made to insert data into the from-table.
+**
+** The sqlite.aFKey hash table stores pointers to this structure
+** given the name of a to-table.  For each to-table, all foreign keys
+** associated with that table are on a linked list using the FKey.pNextTo
+** field.
+*/
+struct FKey {
+  Table *pFrom;     /* The table that constains the REFERENCES clause */
+  FKey *pNextFrom;  /* Next foreign key in pFrom */
+  char *zTo;        /* Name of table that the key points to */
+  FKey *pNextTo;    /* Next foreign key that points to zTo */
+  int nCol;         /* Number of columns in this key */
+  struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
+    int iFrom;         /* Index of column in pFrom */
+    char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
+  } *aCol;          /* One entry for each of nCol column s */
+  u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
+  u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
+  u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
+  u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
+};
+
+/*
+** SQLite supports many different ways to resolve a constraint
+** error.  ROLLBACK processing means that a constraint violation
+** causes the operation in process to fail and for the current transaction
+** to be rolled back.  ABORT processing means the operation in process
+** fails and any prior changes from that one operation are backed out,
+** but the transaction is not rolled back.  FAIL processing means that
+** the operation in progress stops and returns an error code.  But prior
+** changes due to the same operation are not backed out and no rollback
+** occurs.  IGNORE means that the particular row that caused the constraint
+** error is not inserted or updated.  Processing continues and no error
+** is returned.  REPLACE means that preexisting database rows that caused
+** a UNIQUE constraint violation are removed so that the new insert or
+** update can proceed.  Processing continues and no error is reported.
+**
+** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
+** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
+** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
+** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the
+** referenced table row is propagated into the row that holds the
+** foreign key.
+** 
+** The following symbolic values are used to record which type
+** of action to take.
+*/
+#define OE_None     0   /* There is no constraint to check */
+#define OE_Rollback 1   /* Fail the operation and rollback the transaction */
+#define OE_Abort    2   /* Back out changes but do no rollback transaction */
+#define OE_Fail     3   /* Stop the operation but leave all prior changes */
+#define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
+#define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
+
+#define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
+#define OE_SetNull  7   /* Set the foreign key value to NULL */
+#define OE_SetDflt  8   /* Set the foreign key value to its default */
+#define OE_Cascade  9   /* Cascade the changes */
+
+#define OE_Default  99  /* Do whatever the default action is */
+
+
+/*
+** An instance of the following structure is passed as the first
+** argument to sqlite3VdbeKeyCompare and is used to control the 
+** comparison of the two index keys.
+**
+** If the KeyInfo.incrKey value is true and the comparison would
+** otherwise be equal, then return a result as if the second key
+** were larger.
+*/
+struct KeyInfo {
+  sqlite3 *db;        /* The database connection */
+  u8 enc;             /* Text encoding - one of the TEXT_Utf* values */
+  u8 incrKey;         /* Increase 2nd key by epsilon before comparison */
+  u8 prefixIsEqual;   /* Treat a prefix as equal */
+  int nField;         /* Number of entries in aColl[] */
+  u8 *aSortOrder;     /* If defined an aSortOrder[i] is true, sort DESC */
+  CollSeq *aColl[1];  /* Collating sequence for each term of the key */
+};
+
+/*
+** Each SQL index is represented in memory by an
+** instance of the following structure.
+**
+** The columns of the table that are to be indexed are described
+** by the aiColumn[] field of this structure.  For example, suppose
+** we have the following table and index:
+**
+**     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
+**     CREATE INDEX Ex2 ON Ex1(c3,c1);
+**
+** In the Table structure describing Ex1, nCol==3 because there are
+** three columns in the table.  In the Index structure describing
+** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
+** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
+** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
+** The second column to be indexed (c1) has an index of 0 in
+** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
+**
+** The Index.onError field determines whether or not the indexed columns
+** must be unique and what to do if they are not.  When Index.onError=OE_None,
+** it means this is not a unique index.  Otherwise it is a unique index
+** and the value of Index.onError indicate the which conflict resolution 
+** algorithm to employ whenever an attempt is made to insert a non-unique
+** element.
+*/
+struct Index {
+  char *zName;     /* Name of this index */
+  int nColumn;     /* Number of columns in the table used by this index */
+  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
+  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
+  Table *pTable;   /* The SQL table being indexed */
+  int tnum;        /* Page containing root of this index in database file */
+  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
+  char *zColAff;   /* String defining the affinity of each column */
+  Index *pNext;    /* The next index associated with the same table */
+  Schema *pSchema; /* Schema containing this index */
+  u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
+  char **azColl;   /* Array of collation sequence names for index */
+};
+
+/*
+** Each token coming out of the lexer is an instance of
+** this structure.  Tokens are also used as part of an expression.
+**
+** Note if Token.z==0 then Token.dyn and Token.n are undefined and
+** may contain random values.  Do not make any assuptions about Token.dyn
+** and Token.n when Token.z==0.
+*/
+struct Token {
+  const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
+  unsigned dyn  : 1;      /* True for malloced memory, false for static */
+  unsigned n    : 31;     /* Number of characters in this token */
+};
+
+/*
+** An instance of this structure contains information needed to generate
+** code for a SELECT that contains aggregate functions.
+**
+** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
+** pointer to this structure.  The Expr.iColumn field is the index in
+** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
+** code for that node.
+**
+** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
+** original Select structure that describes the SELECT statement.  These
+** fields do not need to be freed when deallocating the AggInfo structure.
+*/
+struct AggInfo {
+  u8 directMode;          /* Direct rendering mode means take data directly
+                          ** from source tables rather than from accumulators */
+  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
+                          ** than the source table */
+  int sortingIdx;         /* Cursor number of the sorting index */
+  ExprList *pGroupBy;     /* The group by clause */
+  int nSortingColumn;     /* Number of columns in the sorting index */
+  struct AggInfo_col {    /* For each column used in source tables */
+    Table *pTab;             /* Source table */
+    int iTable;              /* Cursor number of the source table */
+    int iColumn;             /* Column number within the source table */
+    int iSorterColumn;       /* Column number in the sorting index */
+    int iMem;                /* Memory location that acts as accumulator */
+    Expr *pExpr;             /* The original expression */
+  } *aCol;
+  int nColumn;            /* Number of used entries in aCol[] */
+  int nColumnAlloc;       /* Number of slots allocated for aCol[] */
+  int nAccumulator;       /* Number of columns that show through to the output.
+                          ** Additional columns are used only as parameters to
+                          ** aggregate functions */
+  struct AggInfo_func {   /* For each aggregate function */
+    Expr *pExpr;             /* Expression encoding the function */
+    FuncDef *pFunc;          /* The aggregate function implementation */
+    int iMem;                /* Memory location that acts as accumulator */
+    int iDistinct;           /* Ephermeral table used to enforce DISTINCT */
+  } *aFunc;
+  int nFunc;              /* Number of entries in aFunc[] */
+  int nFuncAlloc;         /* Number of slots allocated for aFunc[] */
+};
+
+/*
+** Each node of an expression in the parse tree is an instance
+** of this structure.
+**
+** Expr.op is the opcode.  The integer parser token codes are reused
+** as opcodes here.  For example, the parser defines TK_GE to be an integer
+** code representing the ">=" operator.  This same integer code is reused
+** to represent the greater-than-or-equal-to operator in the expression
+** tree.
+**
+** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
+** of argument if the expression is a function.
+**
+** Expr.token is the operator token for this node.  For some expressions
+** that have subexpressions, Expr.token can be the complete text that gave
+** rise to the Expr.  In the latter case, the token is marked as being
+** a compound token.
+**
+** An expression of the form ID or ID.ID refers to a column in a table.
+** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
+** the integer cursor number of a VDBE cursor pointing to that table and
+** Expr.iColumn is the column number for the specific column.  If the
+** expression is used as a result in an aggregate SELECT, then the
+** value is also stored in the Expr.iAgg column in the aggregate so that
+** it can be accessed after all aggregates are computed.
+**
+** If the expression is a function, the Expr.iTable is an integer code
+** representing which function.  If the expression is an unbound variable
+** marker (a question mark character '?' in the original SQL) then the
+** Expr.iTable holds the index number for that variable.
+**
+** If the expression is a subquery then Expr.iColumn holds an integer
+** register number containing the result of the subquery.  If the
+** subquery gives a constant result, then iTable is -1.  If the subquery
+** gives a different answer at different times during statement processing
+** then iTable is the address of a subroutine that computes the subquery.
+**
+** The Expr.pSelect field points to a SELECT statement.  The SELECT might
+** be the right operand of an IN operator.  Or, if a scalar SELECT appears
+** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
+** operand.
+**
+** If the Expr is of type OP_Column, and the table it is selecting from
+** is a disk table or the "old.*" pseudo-table, then pTab points to the
+** corresponding table definition.
+*/
+struct Expr {
+  u8 op;                 /* Operation performed by this node */
+  char affinity;         /* The affinity of the column or 0 if not a column */
+  u16 flags;             /* Various flags.  See below */
+  CollSeq *pColl;        /* The collation type of the column or 0 */
+  Expr *pLeft, *pRight;  /* Left and right subnodes */
+  ExprList *pList;       /* A list of expressions used as function arguments
+                         ** or in "<expr> IN (<expr-list)" */
+  Token token;           /* An operand token */
+  Token span;            /* Complete text of the expression */
+  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
+                         ** iColumn-th field of the iTable-th table. */
+  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
+  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
+  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
+  Select *pSelect;       /* When the expression is a sub-select.  Also the
+                         ** right side of "<expr> IN (<select>)" */
+  Table *pTab;           /* Table for OP_Column expressions. */
+/*  Schema *pSchema; */
+#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
+  int nHeight;           /* Height of the tree headed by this node */
+#endif
+};
+
+/*
+** The following are the meanings of bits in the Expr.flags field.
+*/
+#define EP_FromJoin   0x0001  /* Originated in ON or USING clause of a join */
+#define EP_Agg        0x0002  /* Contains one or more aggregate functions */
+#define EP_Resolved   0x0004  /* IDs have been resolved to COLUMNs */
+#define EP_Error      0x0008  /* Expression contains one or more errors */
+#define EP_Distinct   0x0010  /* Aggregate function with DISTINCT keyword */
+#define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
+#define EP_Dequoted   0x0040  /* True if the string has been dequoted */
+#define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
+#define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */
+#define EP_AnyAff     0x0200  /* Can take a cached column of any affinity */
+#define EP_FixedDest  0x0400  /* Result needed in a specific register */
+
+/*
+** These macros can be used to test, set, or clear bits in the 
+** Expr.flags field.
+*/
+#define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))
+#define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)
+#define ExprSetProperty(E,P)     (E)->flags|=(P)
+#define ExprClearProperty(E,P)   (E)->flags&=~(P)
+
+/*
+** A list of expressions.  Each expression may optionally have a
+** name.  An expr/name combination can be used in several ways, such
+** as the list of "expr AS ID" fields following a "SELECT" or in the
+** list of "ID = expr" items in an UPDATE.  A list of expressions can
+** also be used as the argument to a function, in which case the a.zName
+** field is not used.
+*/
+struct ExprList {
+  int nExpr;             /* Number of expressions on the list */
+  int nAlloc;            /* Number of entries allocated below */
+  int iECursor;          /* VDBE Cursor associated with this ExprList */
+  struct ExprList_item {
+    Expr *pExpr;           /* The list of expressions */
+    char *zName;           /* Token associated with this expression */
+    u8 sortOrder;          /* 1 for DESC or 0 for ASC */
+    u8 isAgg;              /* True if this is an aggregate like count(*) */
+    u8 done;               /* A flag to indicate when processing is finished */
+  } *a;                  /* One entry for each expression */
+};
+
+/*
+** An instance of this structure can hold a simple list of identifiers,
+** such as the list "a,b,c" in the following statements:
+**
+**      INSERT INTO t(a,b,c) VALUES ...;
+**      CREATE INDEX idx ON t(a,b,c);
+**      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
+**
+** The IdList.a.idx field is used when the IdList represents the list of
+** column names after a table name in an INSERT statement.  In the statement
+**
+**     INSERT INTO t(a,b,c) ...
+**
+** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
+*/
+struct IdList {
+  struct IdList_item {
+    char *zName;      /* Name of the identifier */
+    int idx;          /* Index in some Table.aCol[] of a column named zName */
+  } *a;
+  int nId;         /* Number of identifiers on the list */
+  int nAlloc;      /* Number of entries allocated for a[] below */
+};
+
+/*
+** The bitmask datatype defined below is used for various optimizations.
+**
+** Changing this from a 64-bit to a 32-bit type limits the number of
+** tables in a join to 32 instead of 64.  But it also reduces the size
+** of the library by 738 bytes on ix86.
+*/
+typedef u64 Bitmask;
+
+/*
+** The following structure describes the FROM clause of a SELECT statement.
+** Each table or subquery in the FROM clause is a separate element of
+** the SrcList.a[] array.
+**
+** With the addition of multiple database support, the following structure
+** can also be used to describe a particular table such as the table that
+** is modified by an INSERT, DELETE, or UPDATE statement.  In standard SQL,
+** such a table must be a simple name: ID.  But in SQLite, the table can
+** now be identified by a database name, a dot, then the table name: ID.ID.
+**
+** The jointype starts out showing the join type between the current table
+** and the next table on the list.  The parser builds the list this way.
+** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
+** jointype expresses the join between the table and the previous table.
+*/
+struct SrcList {
+  i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
+  i16 nAlloc;      /* Number of entries allocated in a[] below */
+  struct SrcList_item {
+    char *zDatabase;  /* Name of database holding this table */
+    char *zName;      /* Name of the table */
+    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
+    Table *pTab;      /* An SQL table corresponding to zName */
+    Select *pSelect;  /* A SELECT statement used in place of a table name */
+    u8 isPopulated;   /* Temporary table associated with SELECT is populated */
+    u8 jointype;      /* Type of join between this able and the previous */
+    int iCursor;      /* The VDBE cursor number used to access this table */
+    Expr *pOn;        /* The ON clause of a join */
+    IdList *pUsing;   /* The USING clause of a join */
+    Bitmask colUsed;  /* Bit N (1<<N) set if column N or pTab is used */
+  } a[1];             /* One entry for each identifier on the list */
+};
+
+/*
+** Permitted values of the SrcList.a.jointype field
+*/
+#define JT_INNER     0x0001    /* Any kind of inner or cross join */
+#define JT_CROSS     0x0002    /* Explicit use of the CROSS keyword */
+#define JT_NATURAL   0x0004    /* True for a "natural" join */
+#define JT_LEFT      0x0008    /* Left outer join */
+#define JT_RIGHT     0x0010    /* Right outer join */
+#define JT_OUTER     0x0020    /* The "OUTER" keyword is present */
+#define JT_ERROR     0x0040    /* unknown or unsupported join type */
+
+/*
+** For each nested loop in a WHERE clause implementation, the WhereInfo
+** structure contains a single instance of this structure.  This structure
+** is intended to be private the the where.c module and should not be
+** access or modified by other modules.
+**
+** The pIdxInfo and pBestIdx fields are used to help pick the best
+** index on a virtual table.  The pIdxInfo pointer contains indexing
+** information for the i-th table in the FROM clause before reordering.
+** All the pIdxInfo pointers are freed by whereInfoFree() in where.c.
+** The pBestIdx pointer is a copy of pIdxInfo for the i-th table after
+** FROM clause ordering.  This is a little confusing so I will repeat
+** it in different words.  WhereInfo.a[i].pIdxInfo is index information 
+** for WhereInfo.pTabList.a[i].  WhereInfo.a[i].pBestInfo is the
+** index information for the i-th loop of the join.  pBestInfo is always
+** either NULL or a copy of some pIdxInfo.  So for cleanup it is 
+** sufficient to free all of the pIdxInfo pointers.
+** 
+*/
+struct WhereLevel {
+  int iFrom;            /* Which entry in the FROM clause */
+  int flags;            /* Flags associated with this level */
+  int iMem;             /* First memory cell used by this level */
+  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
+  Index *pIdx;          /* Index used.  NULL if no index */
+  int iTabCur;          /* The VDBE cursor used to access the table */
+  int iIdxCur;          /* The VDBE cursor used to acesss pIdx */
+  int brk;              /* Jump here to break out of the loop */
+  int nxt;              /* Jump here to start the next IN combination */
+  int cont;             /* Jump here to continue with the next loop cycle */
+  int top;              /* First instruction of interior of the loop */
+  int op, p1, p2;       /* Opcode used to terminate the loop */
+  int nEq;              /* Number of == or IN constraints on this loop */
+  int nIn;              /* Number of IN operators constraining this loop */
+  struct InLoop {
+    int iCur;              /* The VDBE cursor used by this IN operator */
+    int topAddr;           /* Top of the IN loop */
+  } *aInLoop;           /* Information about each nested IN operator */
+  sqlite3_index_info *pBestIdx;  /* Index information for this level */
+
+  /* The following field is really not part of the current level.  But
+  ** we need a place to cache index information for each table in the
+  ** FROM clause and the WhereLevel structure is a convenient place.
+  */
+  sqlite3_index_info *pIdxInfo;  /* Index info for n-th source table */
+};
+
+/*
+** Flags appropriate for the wflags parameter of sqlite3WhereBegin().
+*/
+#define WHERE_ORDERBY_NORMAL     0   /* No-op */
+#define WHERE_ORDERBY_MIN        1   /* ORDER BY processing for min() func */
+#define WHERE_ORDERBY_MAX        2   /* ORDER BY processing for max() func */
+#define WHERE_ONEPASS_DESIRED    4   /* Want to do one-pass UPDATE/DELETE */
+
+/*
+** The WHERE clause processing routine has two halves.  The
+** first part does the start of the WHERE loop and the second
+** half does the tail of the WHERE loop.  An instance of
+** this structure is returned by the first half and passed
+** into the second half to give some continuity.
+*/
+struct WhereInfo {
+  Parse *pParse;       /* Parsing and code generating context */
+  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
+  SrcList *pTabList;   /* List of tables in the join */
+  int iTop;            /* The very beginning of the WHERE loop */
+  int iContinue;       /* Jump here to continue with next record */
+  int iBreak;          /* Jump here to break out of the loop */
+  int nLevel;          /* Number of nested loop */
+  sqlite3_index_info **apInfo;  /* Array of pointers to index info structures */
+  WhereLevel a[1];     /* Information about each nest loop in the WHERE */
+};
+
+/*
+** A NameContext defines a context in which to resolve table and column
+** names.  The context consists of a list of tables (the pSrcList) field and
+** a list of named expression (pEList).  The named expression list may
+** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
+** to the table being operated on by INSERT, UPDATE, or DELETE.  The
+** pEList corresponds to the result set of a SELECT and is NULL for
+** other statements.
+**
+** NameContexts can be nested.  When resolving names, the inner-most 
+** context is searched first.  If no match is found, the next outer
+** context is checked.  If there is still no match, the next context
+** is checked.  This process continues until either a match is found
+** or all contexts are check.  When a match is found, the nRef member of
+** the context containing the match is incremented. 
+**
+** Each subquery gets a new NameContext.  The pNext field points to the
+** NameContext in the parent query.  Thus the process of scanning the
+** NameContext list corresponds to searching through successively outer
+** subqueries looking for a match.
+*/
+struct NameContext {
+  Parse *pParse;       /* The parser */
+  SrcList *pSrcList;   /* One or more tables used to resolve names */
+  ExprList *pEList;    /* Optional list of named expressions */
+  int nRef;            /* Number of names resolved by this context */
+  int nErr;            /* Number of errors encountered while resolving names */
+  u8 allowAgg;         /* Aggregate functions allowed here */
+  u8 hasAgg;           /* True if aggregates are seen */
+  u8 isCheck;          /* True if resolving names in a CHECK constraint */
+  int nDepth;          /* Depth of subquery recursion. 1 for no recursion */
+  AggInfo *pAggInfo;   /* Information about aggregates at this level */
+  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
+};
+
+/*
+** An instance of the following structure contains all information
+** needed to generate code for a single SELECT statement.
+**
+** nLimit is set to -1 if there is no LIMIT clause.  nOffset is set to 0.
+** If there is a LIMIT clause, the parser sets nLimit to the value of the
+** limit and nOffset to the value of the offset (or 0 if there is not
+** offset).  But later on, nLimit and nOffset become the memory locations
+** in the VDBE that record the limit and offset counters.
+**
+** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.
+** These addresses must be stored so that we can go back and fill in
+** the P4_KEYINFO and P2 parameters later.  Neither the KeyInfo nor
+** the number of columns in P2 can be computed at the same time
+** as the OP_OpenEphm instruction is coded because not
+** enough information about the compound query is known at that point.
+** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences
+** for the result set.  The KeyInfo for addrOpenTran[2] contains collating
+** sequences for the ORDER BY clause.
+*/
+struct Select {
+  ExprList *pEList;      /* The fields of the result */
+  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
+  u8 isDistinct;         /* True if the DISTINCT keyword is present */
+  u8 isResolved;         /* True once sqlite3SelectResolve() has run. */
+  u8 isAgg;              /* True if this is an aggregate query */
+  u8 usesEphm;           /* True if uses an OpenEphemeral opcode */
+  u8 disallowOrderBy;    /* Do not allow an ORDER BY to be attached if TRUE */
+  char affinity;         /* MakeRecord with this affinity for SRT_Set */
+  SrcList *pSrc;         /* The FROM clause */
+  Expr *pWhere;          /* The WHERE clause */
+  ExprList *pGroupBy;    /* The GROUP BY clause */
+  Expr *pHaving;         /* The HAVING clause */
+  ExprList *pOrderBy;    /* The ORDER BY clause */
+  Select *pPrior;        /* Prior select in a compound select statement */
+  Select *pNext;         /* Next select to the left in a compound */
+  Select *pRightmost;    /* Right-most select in a compound select statement */
+  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
+  Expr *pOffset;         /* OFFSET expression. NULL means not used. */
+  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
+  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
+};
+
+/*
+** The results of a select can be distributed in several ways.
+*/
+#define SRT_Union        1  /* Store result as keys in an index */
+#define SRT_Except       2  /* Remove result from a UNION index */
+#define SRT_Exists       3  /* Store 1 if the result is not empty */
+#define SRT_Discard      4  /* Do not save the results anywhere */
+
+/* The ORDER BY clause is ignored for all of the above */
+#define IgnorableOrderby(X) ((X->eDest)<=SRT_Discard)
+
+#define SRT_Callback     5  /* Invoke a callback with each row of result */
+#define SRT_Mem          6  /* Store result in a memory cell */
+#define SRT_Set          7  /* Store non-null results as keys in an index */
+#define SRT_Table        8  /* Store result as data with an automatic rowid */
+#define SRT_EphemTab     9  /* Create transient tab and store like SRT_Table */
+#define SRT_Subroutine  10  /* Call a subroutine to handle results */
+
+/*
+** A structure used to customize the behaviour of sqlite3Select(). See
+** comments above sqlite3Select() for details.
+*/
+typedef struct SelectDest SelectDest;
+struct SelectDest {
+  u8 eDest;         /* How to dispose of the results */
+  u8 affinity;      /* Affinity used when eDest==SRT_Set */
+  int iParm;        /* A parameter used by the eDest disposal method */
+  int iMem;         /* Base register where results are written */
+  int nMem;         /* Number of registers allocated */
+};
+
+/*
+** An SQL parser context.  A copy of this structure is passed through
+** the parser and down into all the parser action routine in order to
+** carry around information that is global to the entire parse.
+**
+** The structure is divided into two parts.  When the parser and code
+** generate call themselves recursively, the first part of the structure
+** is constant but the second part is reset at the beginning and end of
+** each recursion.
+**
+** The nTableLock and aTableLock variables are only used if the shared-cache 
+** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
+** used to store the set of table-locks required by the statement being
+** compiled. Function sqlite3TableLock() is used to add entries to the
+** list.
+*/
+struct Parse {
+  sqlite3 *db;         /* The main database structure */
+  int rc;              /* Return code from execution */
+  char *zErrMsg;       /* An error message */
+  Vdbe *pVdbe;         /* An engine for executing database bytecode */
+  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
+  u8 nameClash;        /* A permanent table name clashes with temp table name */
+  u8 checkSchema;      /* Causes schema cookie check after an error */
+  u8 nested;           /* Number of nested calls to the parser/code generator */
+  u8 parseError;       /* True after a parsing error.  Ticket #1794 */
+  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
+  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
+  int aTempReg[8];     /* Holding area for temporary registers */
+  int nRangeReg;       /* Size of the temporary register block */
+  int iRangeReg;       /* First register in temporary register block */
+  int nErr;            /* Number of errors seen */
+  int nTab;            /* Number of previously allocated VDBE cursors */
+  int nMem;            /* Number of memory cells used so far */
+  int nSet;            /* Number of sets used so far */
+  int ckBase;          /* Base register of data during check constraints */
+  int disableColCache; /* True to disable adding to column cache */
+  int nColCache;       /* Number of entries in the column cache */
+  int iColCache;       /* Next entry of the cache to replace */
+  struct yColCache {
+    int iTable;           /* Table cursor number */
+    int iColumn;          /* Table column number */
+    char affChange;       /* True if this register has had an affinity change */
+    int iReg;             /* Register holding value of this column */
+  } aColCache[10];     /* One for each valid column cache entry */
+  u32 writeMask;       /* Start a write transaction on these databases */
+  u32 cookieMask;      /* Bitmask of schema verified databases */
+  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
+  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nTableLock;        /* Number of locks in aTableLock */
+  TableLock *aTableLock; /* Required table locks for shared-cache mode */
+#endif
+  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
+  int regRoot;         /* Register holding root page number for new objects */
+
+  /* Above is constant between recursions.  Below is reset before and after
+  ** each recursion */
+
+  int nVar;            /* Number of '?' variables seen in the SQL so far */
+  int nVarExpr;        /* Number of used slots in apVarExpr[] */
+  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
+  Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */
+  u8 explain;          /* True if the EXPLAIN flag is found on the query */
+  Token sErrToken;     /* The token at which the error occurred */
+  Token sNameToken;    /* Token with unqualified schema object name */
+  Token sLastToken;    /* The last token parsed */
+  const char *zSql;    /* All SQL text */
+  const char *zTail;   /* All SQL text past the last semicolon parsed */
+  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
+  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
+  TriggerStack *trigStack;  /* Trigger actions being coded */
+  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Token sArg;                /* Complete text of a module argument */
+  u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */
+  int nVtabLock;             /* Number of virtual tables to lock */
+  Table **apVtabLock;        /* Pointer to virtual tables needing locking */
+#endif
+#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
+  int nHeight;            /* Expression tree height of current sub-select */
+#endif
+};
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  #define IN_DECLARE_VTAB 0
+#else
+  #define IN_DECLARE_VTAB (pParse->declareVtab)
+#endif
+
+/*
+** An instance of the following structure can be declared on a stack and used
+** to save the Parse.zAuthContext value so that it can be restored later.
+*/
+struct AuthContext {
+  const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
+  Parse *pParse;              /* The Parse structure */
+};
+
+/*
+** Bitfield flags for P2 value in OP_Insert and OP_Delete
+*/
+#define OPFLAG_NCHANGE   1    /* Set to update db->nChange */
+#define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */
+#define OPFLAG_ISUPDATE  4    /* This OP_Insert is an sql UPDATE */
+#define OPFLAG_APPEND    8    /* This is likely to be an append */
+
+/*
+ * Each trigger present in the database schema is stored as an instance of
+ * struct Trigger. 
+ *
+ * Pointers to instances of struct Trigger are stored in two ways.
+ * 1. In the "trigHash" hash table (part of the sqlite3* that represents the 
+ *    database). This allows Trigger structures to be retrieved by name.
+ * 2. All triggers associated with a single table form a linked list, using the
+ *    pNext member of struct Trigger. A pointer to the first element of the
+ *    linked list is stored as the "pTrigger" member of the associated
+ *    struct Table.
+ *
+ * The "step_list" member points to the first element of a linked list
+ * containing the SQL statements specified as the trigger program.
+ */
+struct Trigger {
+  char *name;             /* The name of the trigger                        */
+  char *table;            /* The table or view to which the trigger applies */
+  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
+  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
+  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
+                             the <column-list> is stored here */
+  Token nameToken;        /* Token containing zName. Use during parsing only */
+  Schema *pSchema;        /* Schema containing the trigger */
+  Schema *pTabSchema;     /* Schema containing the table */
+  TriggerStep *step_list; /* Link list of trigger program steps             */
+  Trigger *pNext;         /* Next trigger associated with the table */
+};
+
+/*
+** A trigger is either a BEFORE or an AFTER trigger.  The following constants
+** determine which. 
+**
+** If there are multiple triggers, you might of some BEFORE and some AFTER.
+** In that cases, the constants below can be ORed together.
+*/
+#define TRIGGER_BEFORE  1
+#define TRIGGER_AFTER   2
+
+/*
+ * An instance of struct TriggerStep is used to store a single SQL statement
+ * that is a part of a trigger-program. 
+ *
+ * Instances of struct TriggerStep are stored in a singly linked list (linked
+ * using the "pNext" member) referenced by the "step_list" member of the 
+ * associated struct Trigger instance. The first element of the linked list is
+ * the first step of the trigger-program.
+ * 
+ * The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
+ * "SELECT" statement. The meanings of the other members is determined by the 
+ * value of "op" as follows:
+ *
+ * (op == TK_INSERT)
+ * orconf    -> stores the ON CONFLICT algorithm
+ * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then
+ *              this stores a pointer to the SELECT statement. Otherwise NULL.
+ * target    -> A token holding the name of the table to insert into.
+ * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
+ *              this stores values to be inserted. Otherwise NULL.
+ * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ... 
+ *              statement, then this stores the column-names to be
+ *              inserted into.
+ *
+ * (op == TK_DELETE)
+ * target    -> A token holding the name of the table to delete from.
+ * pWhere    -> The WHERE clause of the DELETE statement if one is specified.
+ *              Otherwise NULL.
+ * 
+ * (op == TK_UPDATE)
+ * target    -> A token holding the name of the table to update rows of.
+ * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
+ *              Otherwise NULL.
+ * pExprList -> A list of the columns to update and the expressions to update
+ *              them to. See sqlite3Update() documentation of "pChanges"
+ *              argument.
+ * 
+ */
+struct TriggerStep {
+  int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
+  int orconf;          /* OE_Rollback etc. */
+  Trigger *pTrig;      /* The trigger that this step is a part of */
+
+  Select *pSelect;     /* Valid for SELECT and sometimes 
+                          INSERT steps (when pExprList == 0) */
+  Token target;        /* Valid for DELETE, UPDATE, INSERT steps */
+  Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
+  ExprList *pExprList; /* Valid for UPDATE statements and sometimes 
+                           INSERT steps (when pSelect == 0)         */
+  IdList *pIdList;     /* Valid for INSERT statements only */
+  TriggerStep *pNext;  /* Next in the link-list */
+  TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
+};
+
+/*
+ * An instance of struct TriggerStack stores information required during code
+ * generation of a single trigger program. While the trigger program is being
+ * coded, its associated TriggerStack instance is pointed to by the
+ * "pTriggerStack" member of the Parse structure.
+ *
+ * The pTab member points to the table that triggers are being coded on. The 
+ * newIdx member contains the index of the vdbe cursor that points at the temp
+ * table that stores the new.* references. If new.* references are not valid
+ * for the trigger being coded (for example an ON DELETE trigger), then newIdx
+ * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
+ *
+ * The ON CONFLICT policy to be used for the trigger program steps is stored 
+ * as the orconf member. If this is OE_Default, then the ON CONFLICT clause 
+ * specified for individual triggers steps is used.
+ *
+ * struct TriggerStack has a "pNext" member, to allow linked lists to be
+ * constructed. When coding nested triggers (triggers fired by other triggers)
+ * each nested trigger stores its parent trigger's TriggerStack as the "pNext" 
+ * pointer. Once the nested trigger has been coded, the pNext value is restored
+ * to the pTriggerStack member of the Parse stucture and coding of the parent
+ * trigger continues.
+ *
+ * Before a nested trigger is coded, the linked list pointed to by the 
+ * pTriggerStack is scanned to ensure that the trigger is not about to be coded
+ * recursively. If this condition is detected, the nested trigger is not coded.
+ */
+struct TriggerStack {
+  Table *pTab;         /* Table that triggers are currently being coded on */
+  int newIdx;          /* Index of vdbe cursor to "new" temp table */
+  int oldIdx;          /* Index of vdbe cursor to "old" temp table */
+  u32 newColMask;
+  u32 oldColMask;
+  int orconf;          /* Current orconf policy */
+  int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */
+  Trigger *pTrigger;   /* The trigger currently being coded */
+  TriggerStack *pNext; /* Next trigger down on the trigger stack */
+};
+
+/*
+** The following structure contains information used by the sqliteFix...
+** routines as they walk the parse tree to make database references
+** explicit.  
+*/
+typedef struct DbFixer DbFixer;
+struct DbFixer {
+  Parse *pParse;      /* The parsing context.  Error messages written here */
+  const char *zDb;    /* Make sure all objects are contained in this database */
+  const char *zType;  /* Type of the container - used for error messages */
+  const Token *pName; /* Name of the container - used for error messages */
+};
+
+/*
+** An objected used to accumulate the text of a string where we
+** do not necessarily know how big the string will be in the end.
+*/
+struct StrAccum {
+  char *zBase;     /* A base allocation.  Not from malloc. */
+  char *zText;     /* The string collected so far */
+  int  nChar;      /* Length of the string so far */
+  int  nAlloc;     /* Amount of space allocated in zText */
+  int  mxAlloc;        /* Maximum allowed string length */
+  u8   mallocFailed;   /* Becomes true if any memory allocation fails */
+  u8   useMalloc;      /* True if zText is enlargable using realloc */
+  u8   tooBig;         /* Becomes true if string size exceeds limits */
+};
+
+/*
+** A pointer to this structure is used to communicate information
+** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
+*/
+typedef struct {
+  sqlite3 *db;        /* The database being initialized */
+  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
+  char **pzErrMsg;    /* Error message stored here */
+  int rc;             /* Result code stored here */
+} InitData;
+
+/*
+** Assuming zIn points to the first byte of a UTF-8 character,
+** advance zIn to point to the first byte of the next UTF-8 character.
+*/
+#define SQLITE_SKIP_UTF8(zIn) {                        \
+  if( (*(zIn++))>=0xc0 ){                              \
+    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
+/*
+** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
+** builds) or a function call (for debugging).  If it is a function call,
+** it allows the operator to set a breakpoint at the spot where database
+** corruption is first detected.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3Corrupt(void);
+# define SQLITE_CORRUPT_BKPT sqlite3Corrupt()
+# define DEBUGONLY(X)        X
+#else
+# define SQLITE_CORRUPT_BKPT SQLITE_CORRUPT
+# define DEBUGONLY(X)
+#endif
+
+/*
+** Internal function prototypes
+*/
+SQLITE_PRIVATE int sqlite3StrICmp(const char *, const char *);
+SQLITE_PRIVATE int sqlite3StrNICmp(const char *, const char *, int);
+SQLITE_PRIVATE int sqlite3IsNumber(const char*, int*, u8);
+
+SQLITE_PRIVATE void *sqlite3MallocZero(unsigned);
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3*, unsigned);
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3*, unsigned);
+SQLITE_PRIVATE char *sqlite3StrDup(const char*);
+SQLITE_PRIVATE char *sqlite3StrNDup(const char*, int);
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3*,const char*);
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3*,const char*, int);
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *, void *, int);
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *, void *, int);
+SQLITE_PRIVATE int sqlite3MallocSize(void *);
+
+SQLITE_PRIVATE int sqlite3IsNaN(double);
+
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
+#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
+SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
+#endif
+#if defined(SQLITE_TEST)
+SQLITE_PRIVATE   void *sqlite3TextToPtr(const char*);
+#endif
+SQLITE_PRIVATE void sqlite3SetString(char **, ...);
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
+SQLITE_PRIVATE void sqlite3ErrorClear(Parse*);
+SQLITE_PRIVATE void sqlite3Dequote(char*);
+SQLITE_PRIVATE void sqlite3DequoteExpr(sqlite3*, Expr*);
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
+SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*, char **);
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
+SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*, int, Expr*, Expr*, const Token*);
+SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
+SQLITE_PRIVATE Expr *sqlite3RegisterExpr(Parse*,Token*);
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprSpan(Expr*,Token*,Token*);
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprDelete(Expr*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*,Token*);
+SQLITE_PRIVATE void sqlite3ExprListDelete(ExprList*);
+SQLITE_PRIVATE int sqlite3Init(sqlite3*, char**);
+SQLITE_PRIVATE int sqlite3InitCallback(void*, int, char**, char**);
+SQLITE_PRIVATE void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
+SQLITE_PRIVATE void sqlite3ResetInternalSchema(sqlite3*, int);
+SQLITE_PRIVATE void sqlite3BeginParse(Parse*,int);
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3*);
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse*,char*,Select*);
+SQLITE_PRIVATE void sqlite3OpenMasterTable(Parse *, int);
+SQLITE_PRIVATE void sqlite3StartTable(Parse*,Token*,Token*,int,int,int,int);
+SQLITE_PRIVATE void sqlite3AddColumn(Parse*,Token*);
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse*, int);
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3AddColumnType(Parse*,Token*);
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,Expr*);
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,Select*);
+
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32);
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
+
+SQLITE_PRIVATE void sqlite3CreateView(Parse*,Token*,Token*,Token*,Select*,int,int);
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+SQLITE_PRIVATE   int sqlite3ViewGetColumnNames(Parse*,Table*);
+#else
+# define sqlite3ViewGetColumnNames(A,B) 0
+#endif
+
+SQLITE_PRIVATE void sqlite3DropTable(Parse*, SrcList*, int, int);
+SQLITE_PRIVATE void sqlite3DeleteTable(Table*);
+SQLITE_PRIVATE void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(sqlite3*,void*,int,int,int*,int*,int*);
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(sqlite3*, IdList*, Token*);
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList*,const char*);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(sqlite3*, SrcList*, Token*, Token*);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*, Token*,
+                                      Select*, Expr*, IdList*);
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(SrcList*);
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse*, SrcList*);
+SQLITE_PRIVATE void sqlite3IdListDelete(IdList*);
+SQLITE_PRIVATE void sqlite3SrcListDelete(SrcList*);
+SQLITE_PRIVATE void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
+                        Token*, int, int);
+SQLITE_PRIVATE void sqlite3DropIndex(Parse*, SrcList*, int);
+SQLITE_PRIVATE int sqlite3Select(Parse*, Select*, SelectDest*, Select*, int, int*, char *aff);
+SQLITE_PRIVATE Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
+                         Expr*,ExprList*,int,Expr*,Expr*);
+SQLITE_PRIVATE void sqlite3SelectDelete(Select*);
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse*, SrcList*);
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse*, Table*, int);
+SQLITE_PRIVATE void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
+SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
+SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse*, int, int);
+SQLITE_PRIVATE void sqlite3ExprClearColumnCache(Parse*, int);
+SQLITE_PRIVATE void sqlite3ExprCacheAffinityChange(Parse*, int, int);
+SQLITE_PRIVATE int sqlite3ExprWritableRegister(Parse*,int,int);
+SQLITE_PRIVATE void sqlite3ExprHardCopy(Parse*,int,int);
+SQLITE_PRIVATE int sqlite3ExprCode(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeAndCache(Parse*, Expr*, int);
+SQLITE_PRIVATE void sqlite3ExprCodeConstants(Parse*, Expr*);
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3*,const char*, const char*);
+SQLITE_PRIVATE Table *sqlite3LocateTable(Parse*,int isView,const char*, const char*);
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3Vacuum(Parse*);
+SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*);
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, Token*);
+SQLITE_PRIVATE int sqlite3ExprCompare(Expr*, Expr*);
+SQLITE_PRIVATE int sqlite3ExprResolveNames(NameContext *, Expr *);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
+SQLITE_PRIVATE Expr *sqlite3CreateIdExpr(Parse *, const char*);
+SQLITE_PRIVATE void sqlite3PrngSaveState(void);
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void);
+SQLITE_PRIVATE void sqlite3PrngResetState(void);
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*);
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse*, int);
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse*, int);
+SQLITE_PRIVATE void sqlite3CommitTransaction(Parse*);
+SQLITE_PRIVATE void sqlite3RollbackTransaction(Parse*);
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr*, int*);
+SQLITE_PRIVATE int sqlite3IsRowid(const char*);
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int);
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int*);
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int);
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int,
+                                     int*,int,int,int,int);
+SQLITE_PRIVATE void sqlite3CompleteInsertion(Parse*, Table*, int, int, int*,int,int,int,int);
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse*, int, int);
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3*,Expr*);
+SQLITE_PRIVATE void sqlite3TokenCopy(sqlite3*,Token*, Token*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3*,IdList*);
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,Select*);
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(sqlite3*);
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(sqlite3*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3SafetyOn(sqlite3*);
+SQLITE_PRIVATE   int sqlite3SafetyOff(sqlite3*);
+#else
+# define sqlite3SafetyOn(A) 0
+# define sqlite3SafetyOff(A) 0
+#endif
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3*);
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3*);
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse*, int);
+SQLITE_PRIVATE void sqlite3MaterializeView(Parse*, Select*, Expr*, int);
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
+                           Expr*,int, int);
+SQLITE_PRIVATE   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
+SQLITE_PRIVATE   void sqlite3DropTrigger(Parse*, SrcList*, int);
+SQLITE_PRIVATE   void sqlite3DropTriggerPtr(Parse*, Trigger*);
+SQLITE_PRIVATE   int sqlite3TriggersExist(Parse*, Table*, int, ExprList*);
+SQLITE_PRIVATE   int sqlite3CodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 
+                           int, int, u32*, u32*);
+  void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
+SQLITE_PRIVATE   void sqlite3DeleteTriggerStep(TriggerStep*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerInsertStep(sqlite3*,Token*, IdList*,
+                                        ExprList*,Select*,int);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, int);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);
+SQLITE_PRIVATE   void sqlite3DeleteTrigger(Trigger*);
+SQLITE_PRIVATE   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
+#else
+# define sqlite3TriggersExist(A,B,C,D,E,F) 0
+# define sqlite3DeleteTrigger(A)
+# define sqlite3DropTriggerPtr(A,B)
+# define sqlite3UnlinkAndDeleteTrigger(A,B,C)
+# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I,J,K) 0
+#endif
+
+SQLITE_PRIVATE int sqlite3JoinType(Parse*, Token*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse*, int);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+SQLITE_PRIVATE   void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
+SQLITE_PRIVATE   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPop(AuthContext*);
+#else
+# define sqlite3AuthRead(a,b,c,d)
+# define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
+# define sqlite3AuthContextPush(a,b,c)
+# define sqlite3AuthContextPop(a)  ((void)(a))
+#endif
+SQLITE_PRIVATE void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3Detach(Parse*, Expr*);
+SQLITE_PRIVATE int sqlite3BtreeFactory(const sqlite3 *db, const char *zFilename,
+                       int omitJournal, int nCache, int flags, Btree **ppBtree);
+SQLITE_PRIVATE int sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
+SQLITE_PRIVATE int sqlite3FixSrcList(DbFixer*, SrcList*);
+SQLITE_PRIVATE int sqlite3FixSelect(DbFixer*, Select*);
+SQLITE_PRIVATE int sqlite3FixExpr(DbFixer*, Expr*);
+SQLITE_PRIVATE int sqlite3FixExprList(DbFixer*, ExprList*);
+SQLITE_PRIVATE int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*,...);
+SQLITE_PRIVATE int sqlite3GetInt32(const char *, int*);
+SQLITE_PRIVATE int sqlite3FitsIn64Bits(const char *, int);
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *pData, int nChar);
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *pData, int nByte);
+SQLITE_PRIVATE int sqlite3Utf8Read(const u8*, const u8*, const u8**);
+
+/*
+** Routines to read and write variable-length integers.  These used to
+** be defined locally, but now we use the varint routines in the util.c
+** file.  Code should use the MACRO forms below, as the Varint32 versions
+** are coded to assume the single byte case is already handled (which 
+** the MACRO form does).
+*/
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char*, u64);
+SQLITE_PRIVATE int sqlite3PutVarint32(unsigned char*, u32);
+SQLITE_PRIVATE int sqlite3GetVarint(const unsigned char *, u64 *);
+SQLITE_PRIVATE int sqlite3GetVarint32(const unsigned char *, u32 *);
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v);
+
+/*
+** The header of a record consists of a sequence variable-length integers.
+** These integers are almost always small and are encoded as a single byte.
+** The following macros take advantage this fact to provide a fast encode
+** and decode of the integers in a record header.  It is faster for the common
+** case where the integer is a single byte.  It is a little slower when the
+** integer is two or more bytes.  But overall it is faster.
+**
+** The following expressions are equivalent:
+**
+**     x = sqlite3GetVarint32( A, &B );
+**     x = sqlite3PutVarint32( A, B );
+**
+**     x = getVarint32( A, B );
+**     x = putVarint32( A, B );
+**
+*/
+#define getVarint32(A,B)  ((*(A)<(unsigned char)0x80) ? ((B) = (u32)*(A)),1 : sqlite3GetVarint32((A), &(B)))
+#define putVarint32(A,B)  (((B)<(u32)0x80) ? (*(A) = (unsigned char)(B)),1 : sqlite3PutVarint32((A), (B)))
+#define getVarint    sqlite3GetVarint
+#define putVarint    sqlite3PutVarint
+
+
+SQLITE_PRIVATE void sqlite3IndexAffinityStr(Vdbe *, Index *);
+SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *, Table *);
+SQLITE_PRIVATE char sqlite3CompareAffinity(Expr *pExpr, char aff2);
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity);
+SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr);
+SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*);
+SQLITE_PRIVATE void sqlite3Error(sqlite3*, int, const char*,...);
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3*, const char *z, int n);
+SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
+SQLITE_PRIVATE const char *sqlite3ErrStr(int);
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse);
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char *,int,int);
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName);
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr);
+SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Parse *pParse, Expr *, Token *);
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *, CollSeq *);
+SQLITE_PRIVATE int sqlite3CheckObjectName(Parse *, const char *);
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *, int);
+
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value*, u8);
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value*, u8);
+SQLITE_PRIVATE void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8, 
+                        void(*)(void*));
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value*);
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *);
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *, const void*, int);
+SQLITE_PRIVATE int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[];
+#endif
+SQLITE_PRIVATE void sqlite3RootPageMoved(Db*, int, int);
+SQLITE_PRIVATE void sqlite3Reindex(Parse*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3AlterFunctions(sqlite3*);
+SQLITE_PRIVATE void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *, int *);
+SQLITE_PRIVATE void sqlite3NestedParse(Parse*, const char*, ...);
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3*);
+SQLITE_PRIVATE void sqlite3CodeSubselect(Parse *, Expr *);
+SQLITE_PRIVATE int sqlite3SelectResolve(Parse *, Select *, NameContext *);
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *, Table *, int);
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *, Token *);
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);
+SQLITE_PRIVATE char sqlite3AffinityType(const Token*);
+SQLITE_PRIVATE void sqlite3Analyze(Parse*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler*);
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3*, Token*);
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3*,int iDB);
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index*);
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3*, int);
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
+SQLITE_PRIVATE void sqlite3AttachFunctions(sqlite3 *);
+SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse*, int, int);
+SQLITE_PRIVATE void sqlite3SchemaFree(void *);
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
+SQLITE_PRIVATE KeyInfo *sqlite3IndexKeyinfo(Parse *, Index *);
+SQLITE_PRIVATE int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *, 
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*));
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);
+
+SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum*,const char*,int);
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
+SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum*);
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
+
+/*
+** The interface to the LEMON-generated parser
+*/
+SQLITE_PRIVATE void *sqlite3ParserAlloc(void*(*)(size_t));
+SQLITE_PRIVATE void sqlite3ParserFree(void*, void(*)(void*));
+SQLITE_PRIVATE void sqlite3Parser(void*, int, Token, Parse*);
+
+SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3*);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE   void sqlite3CloseExtensions(sqlite3*);
+#else
+# define sqlite3CloseExtensions(X)
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE   void sqlite3TableLock(Parse *, int, int, u8, const char *);
+#else
+  #define sqlite3TableLock(v,w,x,y,z)
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int sqlite3Utf8To8(unsigned char*);
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+#  define sqlite3VtabClear(X)
+#  define sqlite3VtabSync(X,Y) (Y)
+#  define sqlite3VtabRollback(X)
+#  define sqlite3VtabCommit(X)
+#else
+SQLITE_PRIVATE    void sqlite3VtabClear(Table*);
+SQLITE_PRIVATE    int sqlite3VtabSync(sqlite3 *db, int rc);
+SQLITE_PRIVATE    int sqlite3VtabRollback(sqlite3 *db);
+SQLITE_PRIVATE    int sqlite3VtabCommit(sqlite3 *db);
+#endif
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse*,Table*);
+SQLITE_PRIVATE void sqlite3VtabLock(sqlite3_vtab*);
+SQLITE_PRIVATE void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);
+SQLITE_PRIVATE void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse*);
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse*, Token*);
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse*, Table*);
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
+SQLITE_PRIVATE void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe*);
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
+
+
+/*
+** Available fault injectors.  Should be numbered beginning with 0.
+*/
+#define SQLITE_FAULTINJECTOR_MALLOC     0
+#define SQLITE_FAULTINJECTOR_COUNT      1
+
+/*
+** The interface to the fault injector subsystem.  If the fault injector
+** mechanism is disabled at compile-time then set up macros so that no
+** unnecessary code is generated.
+*/
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+SQLITE_PRIVATE   void sqlite3FaultConfig(int,int,int);
+SQLITE_PRIVATE   int sqlite3FaultFailures(int);
+SQLITE_PRIVATE   int sqlite3FaultBenignFailures(int);
+SQLITE_PRIVATE   int sqlite3FaultPending(int);
+SQLITE_PRIVATE   void sqlite3FaultBeginBenign(int);
+SQLITE_PRIVATE   void sqlite3FaultEndBenign(int);
+SQLITE_PRIVATE   int sqlite3FaultStep(int);
+#else
+# define sqlite3FaultConfig(A,B,C)
+# define sqlite3FaultFailures(A)         0
+# define sqlite3FaultBenignFailures(A)   0
+# define sqlite3FaultPending(A)          (-1)
+# define sqlite3FaultBeginBenign(A)
+# define sqlite3FaultEndBenign(A)
+# define sqlite3FaultStep(A)             0
+#endif
+  
+  
+
+#define IN_INDEX_ROWID           1
+#define IN_INDEX_EPH             2
+#define IN_INDEX_INDEX           3
+SQLITE_PRIVATE int sqlite3FindInIndex(Parse *, Expr *, int);
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+SQLITE_PRIVATE   int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
+SQLITE_PRIVATE   int sqlite3JournalSize(sqlite3_vfs *);
+SQLITE_PRIVATE   int sqlite3JournalCreate(sqlite3_file *);
+#else
+  #define sqlite3JournalSize(pVfs) ((pVfs)->szOsFile)
+#endif
+
+#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
+SQLITE_PRIVATE   void sqlite3ExprSetHeight(Expr *);
+SQLITE_PRIVATE   int sqlite3SelectExprHeight(Select *);
+#else
+  #define sqlite3ExprSetHeight(x)
+#endif
+
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8*);
+SQLITE_PRIVATE void sqlite3Put4byte(u8*, u32);
+
+#ifdef SQLITE_SSE
+#include "sseInt.h"
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3ParserTrace(FILE*, char *);
+#endif
+
+/*
+** If the SQLITE_ENABLE IOTRACE exists then the global variable
+** sqlite3IoTrace is a pointer to a printf-like routine used to
+** print I/O tracing messages. 
+*/
+#ifdef SQLITE_ENABLE_IOTRACE
+# define IOTRACE(A)  if( sqlite3IoTrace ){ sqlite3IoTrace A; }
+SQLITE_PRIVATE   void sqlite3VdbeIOTraceSql(Vdbe*);
+SQLITE_PRIVATE void (*sqlite3IoTrace)(const char*,...);
+#else
+# define IOTRACE(A)
+# define sqlite3VdbeIOTraceSql(X)
+#endif
+
+#endif
+
+/************** End of sqliteInt.h *******************************************/
+/************** Begin file date.c ********************************************/
+/*
+** 2003 October 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement date and time
+** functions for SQLite.  
+**
+** There is only one exported symbol in this file - the function
+** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
+** All other code has file scope.
+**
+** $Id: date.c,v 1.79 2008/03/20 14:03:29 drh Exp $
+**
+** SQLite processes all times and dates as Julian Day numbers.  The
+** dates and times are stored as the number of days since noon
+** in Greenwich on November 24, 4714 B.C. according to the Gregorian
+** calendar system. 
+**
+** 1970-01-01 00:00:00 is JD 2440587.5
+** 2000-01-01 00:00:00 is JD 2451544.5
+**
+** This implemention requires years to be expressed as a 4-digit number
+** which means that only dates between 0000-01-01 and 9999-12-31 can
+** be represented, even though julian day numbers allow a much wider
+** range of dates.
+**
+** The Gregorian calendar system is used for all dates and times,
+** even those that predate the Gregorian calendar.  Historians usually
+** use the Julian calendar for dates prior to 1582-10-15 and for some
+** dates afterwards, depending on locale.  Beware of this difference.
+**
+** The conversion algorithms are implemented based on descriptions
+** in the following text:
+**
+**      Jean Meeus
+**      Astronomical Algorithms, 2nd Edition, 1998
+**      ISBM 0-943396-61-1
+**      Willmann-Bell, Inc
+**      Richmond, Virginia (USA)
+*/
+#include <ctype.h>
+#include <time.h>
+
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+
+/*
+** A structure for holding a single date and time.
+*/
+typedef struct DateTime DateTime;
+struct DateTime {
+  double rJD;      /* The julian day number */
+  int Y, M, D;     /* Year, month, and day */
+  int h, m;        /* Hour and minutes */
+  int tz;          /* Timezone offset in minutes */
+  double s;        /* Seconds */
+  char validYMD;   /* True if Y,M,D are valid */
+  char validHMS;   /* True if h,m,s are valid */
+  char validJD;    /* True if rJD is valid */
+  char validTZ;    /* True if tz is valid */
+};
+
+
+/*
+** Convert zDate into one or more integers.  Additional arguments
+** come in groups of 5 as follows:
+**
+**       N       number of digits in the integer
+**       min     minimum allowed value of the integer
+**       max     maximum allowed value of the integer
+**       nextC   first character after the integer
+**       pVal    where to write the integers value.
+**
+** Conversions continue until one with nextC==0 is encountered.
+** The function returns the number of successful conversions.
+*/
+static int getDigits(const char *zDate, ...){
+  va_list ap;
+  int val;
+  int N;
+  int min;
+  int max;
+  int nextC;
+  int *pVal;
+  int cnt = 0;
+  va_start(ap, zDate);
+  do{
+    N = va_arg(ap, int);
+    min = va_arg(ap, int);
+    max = va_arg(ap, int);
+    nextC = va_arg(ap, int);
+    pVal = va_arg(ap, int*);
+    val = 0;
+    while( N-- ){
+      if( !isdigit(*(u8*)zDate) ){
+        goto end_getDigits;
+      }
+      val = val*10 + *zDate - '0';
+      zDate++;
+    }
+    if( val<min || val>max || (nextC!=0 && nextC!=*zDate) ){
+      goto end_getDigits;
+    }
+    *pVal = val;
+    zDate++;
+    cnt++;
+  }while( nextC );
+end_getDigits:
+  va_end(ap);
+  return cnt;
+}
+
+/*
+** Read text from z[] and convert into a floating point number.  Return
+** the number of digits converted.
+*/
+#define getValue sqlite3AtoF
+
+/*
+** Parse a timezone extension on the end of a date-time.
+** The extension is of the form:
+**
+**        (+/-)HH:MM
+**
+** Or the "zulu" notation:
+**
+**        Z
+**
+** If the parse is successful, write the number of minutes
+** of change in p->tz and return 0.  If a parser error occurs,
+** return non-zero.
+**
+** A missing specifier is not considered an error.
+*/
+static int parseTimezone(const char *zDate, DateTime *p){
+  int sgn = 0;
+  int nHr, nMn;
+  int c;
+  while( isspace(*(u8*)zDate) ){ zDate++; }
+  p->tz = 0;
+  c = *zDate;
+  if( c=='-' ){
+    sgn = -1;
+  }else if( c=='+' ){
+    sgn = +1;
+  }else if( c=='Z' || c=='z' ){
+    zDate++;
+    goto zulu_time;
+  }else{
+    return c!=0;
+  }
+  zDate++;
+  if( getDigits(zDate, 2, 0, 14, ':', &nHr, 2, 0, 59, 0, &nMn)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  p->tz = sgn*(nMn + nHr*60);
+zulu_time:
+  while( isspace(*(u8*)zDate) ){ zDate++; }
+  return *zDate!=0;
+}
+
+/*
+** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF.
+** The HH, MM, and SS must each be exactly 2 digits.  The
+** fractional seconds FFFF can be one or more digits.
+**
+** Return 1 if there is a parsing error and 0 on success.
+*/
+static int parseHhMmSs(const char *zDate, DateTime *p){
+  int h, m, s;
+  double ms = 0.0;
+  if( getDigits(zDate, 2, 0, 24, ':', &h, 2, 0, 59, 0, &m)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  if( *zDate==':' ){
+    zDate++;
+    if( getDigits(zDate, 2, 0, 59, 0, &s)!=1 ){
+      return 1;
+    }
+    zDate += 2;
+    if( *zDate=='.' && isdigit((u8)zDate[1]) ){
+      double rScale = 1.0;
+      zDate++;
+      while( isdigit(*(u8*)zDate) ){
+        ms = ms*10.0 + *zDate - '0';
+        rScale *= 10.0;
+        zDate++;
+      }
+      ms /= rScale;
+    }
+  }else{
+    s = 0;
+  }
+  p->validJD = 0;
+  p->validHMS = 1;
+  p->h = h;
+  p->m = m;
+  p->s = s + ms;
+  if( parseTimezone(zDate, p) ) return 1;
+  p->validTZ = p->tz!=0;
+  return 0;
+}
+
+/*
+** Convert from YYYY-MM-DD HH:MM:SS to julian day.  We always assume
+** that the YYYY-MM-DD is according to the Gregorian calendar.
+**
+** Reference:  Meeus page 61
+*/
+static void computeJD(DateTime *p){
+  int Y, M, D, A, B, X1, X2;
+
+  if( p->validJD ) return;
+  if( p->validYMD ){
+    Y = p->Y;
+    M = p->M;
+    D = p->D;
+  }else{
+    Y = 2000;  /* If no YMD specified, assume 2000-Jan-01 */
+    M = 1;
+    D = 1;
+  }
+  if( M<=2 ){
+    Y--;
+    M += 12;
+  }
+  A = Y/100;
+  B = 2 - A + (A/4);
+  X1 = 365.25*(Y+4716);
+  X2 = 30.6001*(M+1);
+  p->rJD = X1 + X2 + D + B - 1524.5;
+  p->validJD = 1;
+  if( p->validHMS ){
+    p->rJD += (p->h*3600.0 + p->m*60.0 + p->s)/86400.0;
+    if( p->validTZ ){
+      p->rJD -= p->tz*60/86400.0;
+      p->validYMD = 0;
+      p->validHMS = 0;
+      p->validTZ = 0;
+    }
+  }
+}
+
+/*
+** Parse dates of the form
+**
+**     YYYY-MM-DD HH:MM:SS.FFF
+**     YYYY-MM-DD HH:MM:SS
+**     YYYY-MM-DD HH:MM
+**     YYYY-MM-DD
+**
+** Write the result into the DateTime structure and return 0
+** on success and 1 if the input string is not a well-formed
+** date.
+*/
+static int parseYyyyMmDd(const char *zDate, DateTime *p){
+  int Y, M, D, neg;
+
+  if( zDate[0]=='-' ){
+    zDate++;
+    neg = 1;
+  }else{
+    neg = 0;
+  }
+  if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)!=3 ){
+    return 1;
+  }
+  zDate += 10;
+  while( isspace(*(u8*)zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  if( parseHhMmSs(zDate, p)==0 ){
+    /* We got the time */
+  }else if( *zDate==0 ){
+    p->validHMS = 0;
+  }else{
+    return 1;
+  }
+  p->validJD = 0;
+  p->validYMD = 1;
+  p->Y = neg ? -Y : Y;
+  p->M = M;
+  p->D = D;
+  if( p->validTZ ){
+    computeJD(p);
+  }
+  return 0;
+}
+
+/*
+** Attempt to parse the given string into a Julian Day Number.  Return
+** the number of errors.
+**
+** The following are acceptable forms for the input string:
+**
+**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
+**      DDDD.DD 
+**      now
+**
+** In the first form, the +/-HH:MM is always optional.  The fractional
+** seconds extension (the ".FFF") is optional.  The seconds portion
+** (":SS.FFF") is option.  The year and date can be omitted as long
+** as there is a time string.  The time string can be omitted as long
+** as there is a year and date.
+*/
+static int parseDateOrTime(
+  sqlite3_context *context, 
+  const char *zDate, 
+  DateTime *p
+){
+  memset(p, 0, sizeof(*p));
+  if( parseYyyyMmDd(zDate,p)==0 ){
+    return 0;
+  }else if( parseHhMmSs(zDate, p)==0 ){
+    return 0;
+  }else if( sqlite3StrICmp(zDate,"now")==0){
+    double r;
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    sqlite3OsCurrentTime(db->pVfs, &r);
+    p->rJD = r;
+    p->validJD = 1;
+    return 0;
+  }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){
+    getValue(zDate, &p->rJD);
+    p->validJD = 1;
+    return 0;
+  }
+  return 1;
+}
+
+/*
+** Compute the Year, Month, and Day from the julian day number.
+*/
+static void computeYMD(DateTime *p){
+  int Z, A, B, C, D, E, X1;
+  if( p->validYMD ) return;
+  if( !p->validJD ){
+    p->Y = 2000;
+    p->M = 1;
+    p->D = 1;
+  }else{
+    Z = p->rJD + 0.5;
+    A = (Z - 1867216.25)/36524.25;
+    A = Z + 1 + A - (A/4);
+    B = A + 1524;
+    C = (B - 122.1)/365.25;
+    D = 365.25*C;
+    E = (B-D)/30.6001;
+    X1 = 30.6001*E;
+    p->D = B - D - X1;
+    p->M = E<14 ? E-1 : E-13;
+    p->Y = p->M>2 ? C - 4716 : C - 4715;
+  }
+  p->validYMD = 1;
+}
+
+/*
+** Compute the Hour, Minute, and Seconds from the julian day number.
+*/
+static void computeHMS(DateTime *p){
+  int Z, s;
+  if( p->validHMS ) return;
+  computeJD(p);
+  Z = p->rJD + 0.5;
+  s = (p->rJD + 0.5 - Z)*86400000.0 + 0.5;
+  p->s = 0.001*s;
+  s = p->s;
+  p->s -= s;
+  p->h = s/3600;
+  s -= p->h*3600;
+  p->m = s/60;
+  p->s += s - p->m*60;
+  p->validHMS = 1;
+}
+
+/*
+** Compute both YMD and HMS
+*/
+static void computeYMD_HMS(DateTime *p){
+  computeYMD(p);
+  computeHMS(p);
+}
+
+/*
+** Clear the YMD and HMS and the TZ
+*/
+static void clearYMD_HMS_TZ(DateTime *p){
+  p->validYMD = 0;
+  p->validHMS = 0;
+  p->validTZ = 0;
+}
+
+/*
+** Windows CE does not declare the localtime
+** function as it is not defined anywhere.
+** Anyway we need the forward-declaration to be
+** able to define it later on.
+*/
+#if defined(_WIN32_WCE) && (_WIN32_WCE >= 0x600)
+struct tm *__cdecl localtime(const time_t *t);
+#endif
+
+/*
+** Compute the difference (in days) between localtime and UTC (a.k.a. GMT)
+** for the time value p where p is in UTC.
+*/
+static double localtimeOffset(DateTime *p){
+  DateTime x, y;
+  time_t t;
+  x = *p;
+  computeYMD_HMS(&x);
+  if( x.Y<1971 || x.Y>=2038 ){
+    x.Y = 2000;
+    x.M = 1;
+    x.D = 1;
+    x.h = 0;
+    x.m = 0;
+    x.s = 0.0;
+  } else {
+    int s = x.s + 0.5;
+    x.s = s;
+  }
+  x.tz = 0;
+  x.validJD = 0;
+  computeJD(&x);
+  t = (x.rJD-2440587.5)*86400.0 + 0.5;
+#ifdef HAVE_LOCALTIME_R
+  {
+    struct tm sLocal;
+    localtime_r(&t, &sLocal);
+    y.Y = sLocal.tm_year + 1900;
+    y.M = sLocal.tm_mon + 1;
+    y.D = sLocal.tm_mday;
+    y.h = sLocal.tm_hour;
+    y.m = sLocal.tm_min;
+    y.s = sLocal.tm_sec;
+  }
+#else
+  {
+    struct tm *pTm;
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+    pTm = localtime(&t);
+    y.Y = pTm->tm_year + 1900;
+    y.M = pTm->tm_mon + 1;
+    y.D = pTm->tm_mday;
+    y.h = pTm->tm_hour;
+    y.m = pTm->tm_min;
+    y.s = pTm->tm_sec;
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+  }
+#endif
+  y.validYMD = 1;
+  y.validHMS = 1;
+  y.validJD = 0;
+  y.validTZ = 0;
+  computeJD(&y);
+  return y.rJD - x.rJD;
+}
+
+/*
+** Process a modifier to a date-time stamp.  The modifiers are
+** as follows:
+**
+**     NNN days
+**     NNN hours
+**     NNN minutes
+**     NNN.NNNN seconds
+**     NNN months
+**     NNN years
+**     start of month
+**     start of year
+**     start of week
+**     start of day
+**     weekday N
+**     unixepoch
+**     localtime
+**     utc
+**
+** Return 0 on success and 1 if there is any kind of error.
+*/
+static int parseModifier(const char *zMod, DateTime *p){
+  int rc = 1;
+  int n;
+  double r;
+  char *z, zBuf[30];
+  z = zBuf;
+  for(n=0; n<sizeof(zBuf)-1 && zMod[n]; n++){
+    z[n] = tolower(zMod[n]);
+  }
+  z[n] = 0;
+  switch( z[0] ){
+    case 'l': {
+      /*    localtime
+      **
+      ** Assuming the current time value is UTC (a.k.a. GMT), shift it to
+      ** show local time.
+      */
+      if( strcmp(z, "localtime")==0 ){
+        computeJD(p);
+        p->rJD += localtimeOffset(p);
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'u': {
+      /*
+      **    unixepoch
+      **
+      ** Treat the current value of p->rJD as the number of
+      ** seconds since 1970.  Convert to a real julian day number.
+      */
+      if( strcmp(z, "unixepoch")==0 && p->validJD ){
+        p->rJD = p->rJD/86400.0 + 2440587.5;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }else if( strcmp(z, "utc")==0 ){
+        double c1;
+        computeJD(p);
+        c1 = localtimeOffset(p);
+        p->rJD -= c1;
+        clearYMD_HMS_TZ(p);
+        p->rJD += c1 - localtimeOffset(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'w': {
+      /*
+      **    weekday N
+      **
+      ** Move the date to the same time on the next occurrence of
+      ** weekday N where 0==Sunday, 1==Monday, and so forth.  If the
+      ** date is already on the appropriate weekday, this is a no-op.
+      */
+      if( strncmp(z, "weekday ", 8)==0 && getValue(&z[8],&r)>0
+                 && (n=r)==r && n>=0 && r<7 ){
+        int Z;
+        computeYMD_HMS(p);
+        p->validTZ = 0;
+        p->validJD = 0;
+        computeJD(p);
+        Z = p->rJD + 1.5;
+        Z %= 7;
+        if( Z>n ) Z -= 7;
+        p->rJD += n - Z;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 's': {
+      /*
+      **    start of TTTTT
+      **
+      ** Move the date backwards to the beginning of the current day,
+      ** or month or year.
+      */
+      if( strncmp(z, "start of ", 9)!=0 ) break;
+      z += 9;
+      computeYMD(p);
+      p->validHMS = 1;
+      p->h = p->m = 0;
+      p->s = 0.0;
+      p->validTZ = 0;
+      p->validJD = 0;
+      if( strcmp(z,"month")==0 ){
+        p->D = 1;
+        rc = 0;
+      }else if( strcmp(z,"year")==0 ){
+        computeYMD(p);
+        p->M = 1;
+        p->D = 1;
+        rc = 0;
+      }else if( strcmp(z,"day")==0 ){
+        rc = 0;
+      }
+      break;
+    }
+    case '+':
+    case '-':
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9': {
+      n = getValue(z, &r);
+      assert( n>=1 );
+      if( z[n]==':' ){
+        /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
+        ** specified number of hours, minutes, seconds, and fractional seconds
+        ** to the time.  The ".FFF" may be omitted.  The ":SS.FFF" may be
+        ** omitted.
+        */
+        const char *z2 = z;
+        DateTime tx;
+        int day;
+        if( !isdigit(*(u8*)z2) ) z2++;
+        memset(&tx, 0, sizeof(tx));
+        if( parseHhMmSs(z2, &tx) ) break;
+        computeJD(&tx);
+        tx.rJD -= 0.5;
+        day = (int)tx.rJD;
+        tx.rJD -= day;
+        if( z[0]=='-' ) tx.rJD = -tx.rJD;
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        p->rJD += tx.rJD;
+        rc = 0;
+        break;
+      }
+      z += n;
+      while( isspace(*(u8*)z) ) z++;
+      n = strlen(z);
+      if( n>10 || n<3 ) break;
+      if( z[n-1]=='s' ){ z[n-1] = 0; n--; }
+      computeJD(p);
+      rc = 0;
+      if( n==3 && strcmp(z,"day")==0 ){
+        p->rJD += r;
+      }else if( n==4 && strcmp(z,"hour")==0 ){
+        p->rJD += r/24.0;
+      }else if( n==6 && strcmp(z,"minute")==0 ){
+        p->rJD += r/(24.0*60.0);
+      }else if( n==6 && strcmp(z,"second")==0 ){
+        p->rJD += r/(24.0*60.0*60.0);
+      }else if( n==5 && strcmp(z,"month")==0 ){
+        int x, y;
+        computeYMD_HMS(p);
+        p->M += r;
+        x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+        p->Y += x;
+        p->M -= x*12;
+        p->validJD = 0;
+        computeJD(p);
+        y = r;
+        if( y!=r ){
+          p->rJD += (r - y)*30.0;
+        }
+      }else if( n==4 && strcmp(z,"year")==0 ){
+        computeYMD_HMS(p);
+        p->Y += r;
+        p->validJD = 0;
+        computeJD(p);
+      }else{
+        rc = 1;
+      }
+      clearYMD_HMS_TZ(p);
+      break;
+    }
+    default: {
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** Process time function arguments.  argv[0] is a date-time stamp.
+** argv[1] and following are modifiers.  Parse them all and write
+** the resulting time into the DateTime structure p.  Return 0
+** on success and 1 if there are any errors.
+**
+** If there are zero parameters (if even argv[0] is undefined)
+** then assume a default value of "now" for argv[0].
+*/
+static int isDate(
+  sqlite3_context *context, 
+  int argc, 
+  sqlite3_value **argv, 
+  DateTime *p
+){
+  int i;
+  const unsigned char *z;
+  static const unsigned char zDflt[] = "now";
+  if( argc==0 ){
+    z = zDflt;
+  }else{
+    z = sqlite3_value_text(argv[0]);
+  }
+  if( !z || parseDateOrTime(context, (char*)z, p) ){
+    return 1;
+  }
+  for(i=1; i<argc; i++){
+    if( (z = sqlite3_value_text(argv[i]))==0 || parseModifier((char*)z, p) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** The following routines implement the various date and time functions
+** of SQLite.
+*/
+
+/*
+**    julianday( TIMESTRING, MOD, MOD, ...)
+**
+** Return the julian day number of the date specified in the arguments
+*/
+static void juliandayFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    computeJD(&x);
+    sqlite3_result_double(context, x.rJD);
+  }
+}
+
+/*
+**    datetime( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD HH:MM:SS
+*/
+static void datetimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeYMD_HMS(&x);
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d %02d:%02d:%02d",
+                     x.Y, x.M, x.D, x.h, x.m, (int)(x.s));
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    time( TIMESTRING, MOD, MOD, ...)
+**
+** Return HH:MM:SS
+*/
+static void timeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeHMS(&x);
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%02d:%02d:%02d", x.h, x.m, (int)x.s);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    date( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD
+*/
+static void dateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeYMD(&x);
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d", x.Y, x.M, x.D);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
+**
+** Return a string described by FORMAT.  Conversions as follows:
+**
+**   %d  day of month
+**   %f  ** fractional seconds  SS.SSS
+**   %H  hour 00-24
+**   %j  day of year 000-366
+**   %J  ** Julian day number
+**   %m  month 01-12
+**   %M  minute 00-59
+**   %s  seconds since 1970-01-01
+**   %S  seconds 00-59
+**   %w  day of week 0-6  sunday==0
+**   %W  week of year 00-53
+**   %Y  year 0000-9999
+**   %%  %
+*/
+static void strftimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  u64 n;
+  int i, j;
+  char *z;
+  const char *zFmt = (const char*)sqlite3_value_text(argv[0]);
+  char zBuf[100];
+  if( zFmt==0 || isDate(context, argc-1, argv+1, &x) ) return;
+  for(i=0, n=1; zFmt[i]; i++, n++){
+    if( zFmt[i]=='%' ){
+      switch( zFmt[i+1] ){
+        case 'd':
+        case 'H':
+        case 'm':
+        case 'M':
+        case 'S':
+        case 'W':
+          n++;
+          /* fall thru */
+        case 'w':
+        case '%':
+          break;
+        case 'f':
+          n += 8;
+          break;
+        case 'j':
+          n += 3;
+          break;
+        case 'Y':
+          n += 8;
+          break;
+        case 's':
+        case 'J':
+          n += 50;
+          break;
+        default:
+          return;  /* ERROR.  return a NULL */
+      }
+      i++;
+    }
+  }
+  if( n<sizeof(zBuf) ){
+    z = zBuf;
+  }else if( n>sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(context);
+    return;
+  }else{
+    z = sqlite3_malloc( n );
+    if( z==0 ){
+      sqlite3_result_error_nomem(context);
+      return;
+    }
+  }
+  computeJD(&x);
+  computeYMD_HMS(&x);
+  for(i=j=0; zFmt[i]; i++){
+    if( zFmt[i]!='%' ){
+      z[j++] = zFmt[i];
+    }else{
+      i++;
+      switch( zFmt[i] ){
+        case 'd':  sqlite3_snprintf(3, &z[j],"%02d",x.D); j+=2; break;
+        case 'f': {
+          double s = x.s;
+          if( s>59.999 ) s = 59.999;
+          sqlite3_snprintf(7, &z[j],"%06.3f", s);
+          j += strlen(&z[j]);
+          break;
+        }
+        case 'H':  sqlite3_snprintf(3, &z[j],"%02d",x.h); j+=2; break;
+        case 'W': /* Fall thru */
+        case 'j': {
+          int nDay;             /* Number of days since 1st day of year */
+          DateTime y = x;
+          y.validJD = 0;
+          y.M = 1;
+          y.D = 1;
+          computeJD(&y);
+          nDay = x.rJD - y.rJD + 0.5;
+          if( zFmt[i]=='W' ){
+            int wd;   /* 0=Monday, 1=Tuesday, ... 6=Sunday */
+            wd = ((int)(x.rJD+0.5)) % 7;
+            sqlite3_snprintf(3, &z[j],"%02d",(nDay+7-wd)/7);
+            j += 2;
+          }else{
+            sqlite3_snprintf(4, &z[j],"%03d",nDay+1);
+            j += 3;
+          }
+          break;
+        }
+        case 'J': {
+          sqlite3_snprintf(20, &z[j],"%.16g",x.rJD);
+          j+=strlen(&z[j]);
+          break;
+        }
+        case 'm':  sqlite3_snprintf(3, &z[j],"%02d",x.M); j+=2; break;
+        case 'M':  sqlite3_snprintf(3, &z[j],"%02d",x.m); j+=2; break;
+        case 's': {
+          sqlite3_snprintf(30,&z[j],"%d",
+                           (int)((x.rJD-2440587.5)*86400.0 + 0.5));
+          j += strlen(&z[j]);
+          break;
+        }
+        case 'S':  sqlite3_snprintf(3,&z[j],"%02d",(int)x.s); j+=2; break;
+        case 'w':  z[j++] = (((int)(x.rJD+1.5)) % 7) + '0'; break;
+        case 'Y':  sqlite3_snprintf(5,&z[j],"%04d",x.Y); j+=strlen(&z[j]);break;
+        default:   z[j++] = '%'; break;
+      }
+    }
+  }
+  z[j] = 0;
+  sqlite3_result_text(context, z, -1,
+                      z==zBuf ? SQLITE_TRANSIENT : sqlite3_free);
+}
+
+/*
+** current_time()
+**
+** This function returns the same value as time('now').
+*/
+static void ctimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  timeFunc(context, 0, 0);
+}
+
+/*
+** current_date()
+**
+** This function returns the same value as date('now').
+*/
+static void cdateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  dateFunc(context, 0, 0);
+}
+
+/*
+** current_timestamp()
+**
+** This function returns the same value as datetime('now').
+*/
+static void ctimestampFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  datetimeFunc(context, 0, 0);
+}
+#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
+
+#ifdef SQLITE_OMIT_DATETIME_FUNCS
+/*
+** If the library is compiled to omit the full-scale date and time
+** handling (to get a smaller binary), the following minimal version
+** of the functions current_time(), current_date() and current_timestamp()
+** are included instead. This is to support column declarations that
+** include "DEFAULT CURRENT_TIME" etc.
+**
+** This function uses the C-library functions time(), gmtime()
+** and strftime(). The format string to pass to strftime() is supplied
+** as the user-data for the function.
+*/
+static void currentTimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  time_t t;
+  char *zFormat = (char *)sqlite3_user_data(context);
+  sqlite3 *db;
+  double rT;
+  char zBuf[20];
+
+  db = sqlite3_context_db_handle(context);
+  sqlite3OsCurrentTime(db->pVfs, &rT);
+  t = 86400.0*(rT - 2440587.5) + 0.5;
+#ifdef HAVE_GMTIME_R
+  {
+    struct tm sNow;
+    gmtime_r(&t, &sNow);
+    strftime(zBuf, 20, zFormat, &sNow);
+  }
+#else
+  {
+    struct tm *pTm;
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+    pTm = gmtime(&t);
+    strftime(zBuf, 20, zFormat, pTm);
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+  }
+#endif
+
+  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+}
+#endif
+
+/*
+** This function registered all of the above C functions as SQL
+** functions.  This should be the only routine in this file with
+** external linkage.
+*/
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(sqlite3 *db){
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+  static const struct {
+     char *zName;
+     int nArg;
+     void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aFuncs[] = {
+    { "julianday", -1, juliandayFunc   },
+    { "date",      -1, dateFunc        },
+    { "time",      -1, timeFunc        },
+    { "datetime",  -1, datetimeFunc    },
+    { "strftime",  -1, strftimeFunc    },
+    { "current_time",       0, ctimeFunc      },
+    { "current_timestamp",  0, ctimestampFunc },
+    { "current_date",       0, cdateFunc      },
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
+        SQLITE_UTF8, 0, aFuncs[i].xFunc, 0, 0);
+  }
+#else
+  static const struct {
+     char *zName;
+     char *zFormat;
+  } aFuncs[] = {
+    { "current_time", "%H:%M:%S" },
+    { "current_date", "%Y-%m-%d" },
+    { "current_timestamp", "%Y-%m-%d %H:%M:%S" }
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    sqlite3CreateFunc(db, aFuncs[i].zName, 0, SQLITE_UTF8, 
+        aFuncs[i].zFormat, currentTimeFunc, 0, 0);
+  }
+#endif
+}
+
+/************** End of date.c ************************************************/
+/************** Begin file os.c **********************************************/
+/*
+** 2005 November 29
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains OS interface code that is common to all
+** architectures.
+*/
+#define _SQLITE_OS_C_ 1
+#undef _SQLITE_OS_C_
+
+/*
+** The default SQLite sqlite3_vfs implementations do not allocate
+** memory (actually, os_unix.c allocates a small amount of memory
+** from within OsOpen()), but some third-party implementations may.
+** So we test the effects of a malloc() failing and the sqlite3OsXXX()
+** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
+**
+** The following functions are instrumented for malloc() failure 
+** testing:
+**
+**     sqlite3OsOpen()
+**     sqlite3OsRead()
+**     sqlite3OsWrite()
+**     sqlite3OsSync()
+**     sqlite3OsLock()
+**
+*/
+#if defined(SQLITE_TEST) && (OS_WIN==0)
+  #define DO_OS_MALLOC_TEST if (1) {            \
+    void *pTstAlloc = sqlite3_malloc(10);       \
+    if (!pTstAlloc) return SQLITE_IOERR_NOMEM;  \
+    sqlite3_free(pTstAlloc);                    \
+  }
+#else
+  #define DO_OS_MALLOC_TEST
+#endif
+
+/*
+** The following routines are convenience wrappers around methods
+** of the sqlite3_file object.  This is mostly just syntactic sugar. All
+** of this would be completely automatic if SQLite were coded using
+** C++ instead of plain old C.
+*/
+SQLITE_PRIVATE int sqlite3OsClose(sqlite3_file *pId){
+  int rc = SQLITE_OK;
+  if( pId->pMethods ){
+    rc = pId->pMethods->xClose(pId);
+    pId->pMethods = 0;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST;
+  return id->pMethods->xRead(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST;
+  return id->pMethods->xWrite(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file *id, i64 size){
+  return id->pMethods->xTruncate(id, size);
+}
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file *id, int flags){
+  DO_OS_MALLOC_TEST;
+  return id->pMethods->xSync(id, flags);
+}
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
+  return id->pMethods->xFileSize(id, pSize);
+}
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file *id, int lockType){
+  DO_OS_MALLOC_TEST;
+  return id->pMethods->xLock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file *id, int lockType){
+  return id->pMethods->xUnlock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id){
+  return id->pMethods->xCheckReservedLock(id);
+}
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
+  return id->pMethods->xFileControl(id,op,pArg);
+}
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
+  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+}
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+  return id->pMethods->xDeviceCharacteristics(id);
+}
+
+/*
+** The next group of routines are convenience wrappers around the
+** VFS methods.
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  sqlite3_file *pFile, 
+  int flags, 
+  int *pFlagsOut
+){
+  DO_OS_MALLOC_TEST;
+  return pVfs->xOpen(pVfs, zPath, pFile, flags, pFlagsOut);
+}
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  return pVfs->xDelete(pVfs, zPath, dirSync);
+}
+SQLITE_PRIVATE int sqlite3OsAccess(sqlite3_vfs *pVfs, const char *zPath, int flags){
+  int rc;
+#ifdef SQLITE_TEST
+  void *pTstAlloc = sqlite3_malloc(10);
+  if (!pTstAlloc) return -1;
+  sqlite3_free(pTstAlloc);
+#endif
+  rc = pVfs->xAccess(pVfs, zPath, flags);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3OsGetTempname(sqlite3_vfs *pVfs, int nBufOut, char *zBufOut){
+  return pVfs->xGetTempname(pVfs, nBufOut, zBufOut);
+}
+SQLITE_PRIVATE int sqlite3OsFullPathname(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  int nPathOut, 
+  char *zPathOut
+){
+  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
+}
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return pVfs->xDlOpen(pVfs, zPath);
+}
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  pVfs->xDlError(pVfs, nByte, zBufOut);
+}
+SQLITE_PRIVATE void *sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
+  return pVfs->xDlSym(pVfs, pHandle, zSymbol);
+}
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  pVfs->xDlClose(pVfs, pHandle);
+}
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  return pVfs->xRandomness(pVfs, nByte, zBufOut);
+}
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
+  return pVfs->xSleep(pVfs, nMicro);
+}
+SQLITE_PRIVATE int sqlite3OsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  return pVfs->xCurrentTime(pVfs, pTimeOut);
+}
+
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(
+  sqlite3_vfs *pVfs, 
+  const char *zFile, 
+  sqlite3_file **ppFile, 
+  int flags,
+  int *pOutFlags
+){
+  int rc = SQLITE_NOMEM;
+  sqlite3_file *pFile;
+  pFile = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile);
+  if( pFile ){
+    rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pFile);
+    }else{
+      *ppFile = pFile;
+    }
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *pFile){
+  int rc = SQLITE_OK;
+  assert( pFile );
+  rc = sqlite3OsClose(pFile);
+  sqlite3_free(pFile);
+  return rc;
+}
+
+/*
+** The list of all registered VFS implementations.  This list is
+** initialized to the single VFS returned by sqlite3OsDefaultVfs()
+** upon the first call to sqlite3_vfs_find().
+*/
+static sqlite3_vfs *vfsList = 0;
+
+/*
+** Locate a VFS by name.  If no name is given, simply return the
+** first VFS on the list.
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_vfs *pVfs = 0;
+  static int isInit = 0;
+  sqlite3_mutex_enter(mutex);
+  if( !isInit ){
+    vfsList = sqlite3OsDefaultVfs();
+    isInit = 1;
+  }
+  for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
+    if( zVfs==0 ) break;
+    if( strcmp(zVfs, pVfs->zName)==0 ) break;
+  }
+  sqlite3_mutex_leave(mutex);
+  return pVfs;
+}
+
+/*
+** Unlink a VFS from the linked list
+*/
+static void vfsUnlink(sqlite3_vfs *pVfs){
+  assert( sqlite3_mutex_held(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER)) );
+  if( pVfs==0 ){
+    /* No-op */
+  }else if( vfsList==pVfs ){
+    vfsList = pVfs->pNext;
+  }else if( vfsList ){
+    sqlite3_vfs *p = vfsList;
+    while( p->pNext && p->pNext!=pVfs ){
+      p = p->pNext;
+    }
+    if( p->pNext==pVfs ){
+      p->pNext = pVfs->pNext;
+    }
+  }
+}
+
+/*
+** Register a VFS with the system.  It is harmless to register the same
+** VFS multiple times.  The new VFS becomes the default if makeDflt is
+** true.
+*/
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_vfs_find(0);  /* Make sure we are initialized */
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  if( makeDflt || vfsList==0 ){
+    pVfs->pNext = vfsList;
+    vfsList = pVfs;
+  }else{
+    pVfs->pNext = vfsList->pNext;
+    vfsList->pNext = pVfs;
+  }
+  assert(vfsList);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Unregister a VFS so that it is no longer accessible.
+*/
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Provide a default sqlite3OsDefaultVfs() implementation in the
+** cases where none of the standard backends are used.
+*/
+#if !OS_UNIX && !OS_WIN && !OS_OS2
+SQLITE_PRIVATE sqlite3_vfs *sqlite3OsDefaultVfs(void){ return 0; }
+#endif
+
+/************** End of os.c **************************************************/
+/************** Begin file fault.c *******************************************/
+/*
+** 2008 Jan 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement a fault-injector used for
+** testing and verification of SQLite.
+**
+** Subsystems within SQLite can call sqlite3FaultStep() to see if
+** they should simulate a fault.  sqlite3FaultStep() normally returns
+** zero but will return non-zero if a fault should be simulated.
+** Fault injectors can be used, for example, to simulate memory
+** allocation failures or I/O errors.
+**
+** The fault injector is omitted from the code if SQLite is
+** compiled with -DSQLITE_OMIT_BUILTIN_TEST=1.  There is a very
+** small performance hit for leaving the fault injector in the code.
+** Commerical products will probably want to omit the fault injector
+** from production builds.  But safety-critical systems who work
+** under the motto "fly what you test and test what you fly" may
+** choose to leave the fault injector enabled even in production.
+*/
+
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+
+/*
+** There can be various kinds of faults.  For example, there can be
+** a memory allocation failure.  Or an I/O failure.  For each different
+** fault type, there is a separate FaultInjector structure to keep track
+** of the status of that fault.
+*/
+static struct FaultInjector {
+  int iCountdown;   /* Number of pending successes before we hit a failure */
+  int nRepeat;      /* Number of times to repeat the failure */
+  int nBenign;      /* Number of benign failures seen since last config */
+  int nFail;        /* Number of failures seen since last config */
+  u8 enable;        /* True if enabled */
+  i16 benign;       /* Positive if next failure will be benign */
+} aFault[SQLITE_FAULTINJECTOR_COUNT];
+
+/*
+** This routine configures and enables a fault injector.  After
+** calling this routine, aFaultStep() will return false (zero)
+** nDelay times, then it will return true nRepeat times,
+** then it will again begin returning false.
+*/
+SQLITE_PRIVATE void sqlite3FaultConfig(int id, int nDelay, int nRepeat){
+  assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+  aFault[id].iCountdown = nDelay;
+  aFault[id].nRepeat = nRepeat;
+  aFault[id].nBenign = 0;
+  aFault[id].nFail = 0;
+  aFault[id].enable = nDelay>=0;
+  aFault[id].benign = 0;
+}
+
+/*
+** Return the number of faults (both hard and benign faults) that have
+** occurred since the injector was last configured.
+*/
+SQLITE_PRIVATE int sqlite3FaultFailures(int id){
+  assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+  return aFault[id].nFail;
+}
+
+/*
+** Return the number of benign faults that have occurred since the
+** injector was last configured.
+*/
+SQLITE_PRIVATE int sqlite3FaultBenignFailures(int id){
+  assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+  return aFault[id].nBenign;
+}
+
+/*
+** Return the number of successes that will occur before the next failure.
+** If no failures are scheduled, return -1.
+*/
+SQLITE_PRIVATE int sqlite3FaultPending(int id){
+  assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+  if( aFault[id].enable ){
+    return aFault[id].iCountdown;
+  }else{
+    return -1;
+  }
+}
+
+/* 
+** After this routine causes subsequent faults to be either benign
+** or hard (not benign), according to the "enable" parameter.
+**
+** Most faults are hard.  In other words, most faults cause
+** an error to be propagated back up to the application interface.
+** However, sometimes a fault is easily recoverable.  For example,
+** if a malloc fails while resizing a hash table, this is completely
+** recoverable simply by not carrying out the resize.  The hash table
+** will continue to function normally.  So a malloc failure during
+** a hash table resize is a benign fault.  
+*/
+SQLITE_PRIVATE void sqlite3FaultBeginBenign(int id){
+  if( id<0 ){
+    for(id=0; id<SQLITE_FAULTINJECTOR_COUNT; id++){
+      aFault[id].benign++;
+    }
+  }else{
+    assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+    aFault[id].benign++;
+  }
+}
+SQLITE_PRIVATE void sqlite3FaultEndBenign(int id){
+  if( id<0 ){
+    for(id=0; id<SQLITE_FAULTINJECTOR_COUNT; id++){
+      assert( aFault[id].benign>0 );
+      aFault[id].benign--;
+    }
+  }else{
+    assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+    assert( aFault[id].benign>0 );
+    aFault[id].benign--;
+  }
+}
+
+/*
+** This routine exists as a place to set a breakpoint that will
+** fire on any simulated fault.
+*/
+static void sqlite3Fault(void){
+  static int cnt = 0;
+  cnt++;
+}
+
+
+/*
+** Check to see if a fault should be simulated.  Return true to simulate
+** the fault.  Return false if the fault should not be simulated.
+*/
+SQLITE_PRIVATE int sqlite3FaultStep(int id){
+  assert( id>=0 && id<SQLITE_FAULTINJECTOR_COUNT );
+  if( likely(!aFault[id].enable) ){
+    return 0;
+  }
+  if( aFault[id].iCountdown>0 ){
+    aFault[id].iCountdown--;
+    return 0;
+  }
+  sqlite3Fault();
+  aFault[id].nFail++;
+  if( aFault[id].benign>0 ){
+    aFault[id].nBenign++;
+  }
+  aFault[id].nRepeat--;
+  if( aFault[id].nRepeat<=0 ){
+    aFault[id].enable = 0;
+  }
+  return 1;  
+}
+
+#endif /* SQLITE_OMIT_BUILTIN_TEST */
+
+/************** End of fault.c ***********************************************/
+/************** Begin file mem1.c ********************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.  
+**
+** $Id: mem1.c,v 1.17 2008/03/18 00:07:11 drh Exp $
+*/
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#ifdef SQLITE_SYSTEM_MALLOC
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** The alarm callback and its arguments.  The mem.mutex lock will
+  ** be held while the callback is running.  Recursive calls into
+  ** the memory subsystem are allowed, but no new callbacks will be
+  ** issued.  The alarmBusy variable is set to prevent recursive
+  ** callbacks.
+  */
+  sqlite3_int64 alarmThreshold;
+  void (*alarmCallback)(void*, sqlite3_int64,int);
+  void *alarmArg;
+  int alarmBusy;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+  
+  /*
+  ** Current allocation and high-water mark.
+  */
+  sqlite3_int64 nowUsed;
+  sqlite3_int64 mxUsed;
+  
+ 
+} mem;
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+*/
+static void enterMem(void){
+  if( mem.mutex==0 ){
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem.mutex);
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.nowUsed;
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.mxUsed;
+  if( resetFlag ){
+    mem.mxUsed = mem.nowUsed;
+  }
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Change the alarm callback
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  enterMem();
+  mem.alarmCallback = xCallback;
+  mem.alarmArg = pArg;
+  mem.alarmThreshold = iThreshold;
+  sqlite3_mutex_leave(mem.mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Trigger the alarm 
+*/
+static void sqlite3MemsysAlarm(int nByte){
+  void (*xCallback)(void*,sqlite3_int64,int);
+  sqlite3_int64 nowUsed;
+  void *pArg;
+  if( mem.alarmCallback==0 || mem.alarmBusy  ) return;
+  mem.alarmBusy = 1;
+  xCallback = mem.alarmCallback;
+  nowUsed = mem.nowUsed;
+  pArg = mem.alarmArg;
+  sqlite3_mutex_leave(mem.mutex);
+  xCallback(pArg, nowUsed, nByte);
+  sqlite3_mutex_enter(mem.mutex);
+  mem.alarmBusy = 0;
+}
+
+/*
+** Allocate nBytes of memory
+*/
+SQLITE_API void *sqlite3_malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    enterMem();
+    if( mem.alarmCallback!=0 && mem.nowUsed+nBytes>=mem.alarmThreshold ){
+      sqlite3MemsysAlarm(nBytes);
+    }
+    if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
+      p = 0;
+    }else{
+      p = malloc(nBytes+8);
+      if( p==0 ){
+        sqlite3MemsysAlarm(nBytes);
+        p = malloc(nBytes+8);
+      }
+    }
+    if( p ){
+      p[0] = nBytes;
+      p++;
+      mem.nowUsed += nBytes;
+      if( mem.nowUsed>mem.mxUsed ){
+        mem.mxUsed = mem.nowUsed;
+      }
+    }
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  return (void*)p; 
+}
+
+/*
+** Free memory.
+*/
+SQLITE_API void sqlite3_free(void *pPrior){
+  sqlite3_int64 *p;
+  int nByte;
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  p = pPrior;
+  p--;
+  nByte = (int)*p;
+  sqlite3_mutex_enter(mem.mutex);
+  mem.nowUsed -= nByte;
+  free(p);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Return the number of bytes allocated at p.
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(void *p){
+  sqlite3_int64 *pInt;
+  if( !p ) return 0;
+  pInt = p;
+  return pInt[-1];
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+SQLITE_API void *sqlite3_realloc(void *pPrior, int nBytes){
+  int nOld;
+  sqlite3_int64 *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  p = pPrior;
+  p--;
+  nOld = (int)p[0];
+  assert( mem.mutex!=0 );
+  sqlite3_mutex_enter(mem.mutex);
+  if( mem.nowUsed+nBytes-nOld>=mem.alarmThreshold ){
+    sqlite3MemsysAlarm(nBytes-nOld);
+  }
+  if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
+    p = 0;
+  }else{
+    p = realloc(p, nBytes+8);
+    if( p==0 ){
+      sqlite3MemsysAlarm(nBytes);
+      p = pPrior;
+      p--;
+      p = realloc(p, nBytes+8);
+    }
+  }
+  if( p ){
+    p[0] = nBytes;
+    p++;
+    mem.nowUsed += nBytes-nOld;
+    if( mem.nowUsed>mem.mxUsed ){
+      mem.mxUsed = mem.nowUsed;
+    }
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return (void*)p;
+}
+
+#endif /* SQLITE_SYSTEM_MALLOC */
+
+/************** End of mem1.c ************************************************/
+/************** Begin file mem2.c ********************************************/
+/*
+** 2007 August 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.  
+**
+** $Id: mem2.c,v 1.26 2008/04/10 14:57:25 drh Exp $
+*/
+
+/*
+** This version of the memory allocator is used only if the
+** SQLITE_MEMDEBUG macro is defined
+*/
+#ifdef SQLITE_MEMDEBUG
+
+/*
+** The backtrace functionality is only available with GLIBC
+*/
+#ifdef __GLIBC__
+  extern int backtrace(void**,int);
+  extern void backtrace_symbols_fd(void*const*,int,int);
+#else
+# define backtrace(A,B) 0
+# define backtrace_symbols_fd(A,B,C)
+#endif
+
+/*
+** Each memory allocation looks like this:
+**
+**  ------------------------------------------------------------------------
+**  | Title |  backtrace pointers |  MemBlockHdr |  allocation |  EndGuard |
+**  ------------------------------------------------------------------------
+**
+** The application code sees only a pointer to the allocation.  We have
+** to back up from the allocation pointer to find the MemBlockHdr.  The
+** MemBlockHdr tells us the size of the allocation and the number of
+** backtrace pointers.  There is also a guard word at the end of the
+** MemBlockHdr.
+*/
+struct MemBlockHdr {
+  i64 iSize;                          /* Size of this allocation */
+  struct MemBlockHdr *pNext, *pPrev;  /* Linked list of all unfreed memory */
+  char nBacktrace;                    /* Number of backtraces on this alloc */
+  char nBacktraceSlots;               /* Available backtrace slots */
+  short nTitle;                       /* Bytes of title; includes '\0' */
+  int iForeGuard;                     /* Guard word for sanity */
+};
+
+/*
+** Guard words
+*/
+#define FOREGUARD 0x80F5E153
+#define REARGUARD 0xE4676B53
+
+/*
+** Number of malloc size increments to track.
+*/
+#define NCSIZE  1000
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** The alarm callback and its arguments.  The mem.mutex lock will
+  ** be held while the callback is running.  Recursive calls into
+  ** the memory subsystem are allowed, but no new callbacks will be
+  ** issued.  The alarmBusy variable is set to prevent recursive
+  ** callbacks.
+  */
+  sqlite3_int64 alarmThreshold;
+  void (*alarmCallback)(void*, sqlite3_int64, int);
+  void *alarmArg;
+  int alarmBusy;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+  
+  /*
+  ** Current allocation and high-water mark.
+  */
+  sqlite3_int64 nowUsed;
+  sqlite3_int64 mxUsed;
+  
+  /*
+  ** Head and tail of a linked list of all outstanding allocations
+  */
+  struct MemBlockHdr *pFirst;
+  struct MemBlockHdr *pLast;
+  
+  /*
+  ** The number of levels of backtrace to save in new allocations.
+  */
+  int nBacktrace;
+  void (*xBacktrace)(int, int, void **);
+
+  /*
+  ** Title text to insert in front of each block
+  */
+  int nTitle;        /* Bytes of zTitle to save.  Includes '\0' and padding */
+  char zTitle[100];  /* The title text */
+
+  /* 
+  ** sqlite3MallocDisallow() increments the following counter.
+  ** sqlite3MallocAllow() decrements it.
+  */
+  int disallow; /* Do not allow memory allocation */
+
+  /*
+  ** Gather statistics on the sizes of memory allocations.
+  ** sizeCnt[i] is the number of allocation attempts of i*8
+  ** bytes.  i==NCSIZE is the number of allocation attempts for
+  ** sizes more than NCSIZE*8 bytes.
+  */
+  int sizeCnt[NCSIZE];
+
+} mem;
+
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+*/
+static void enterMem(void){
+  if( mem.mutex==0 ){
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem.mutex);
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.nowUsed;
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.mxUsed;
+  if( resetFlag ){
+    mem.mxUsed = mem.nowUsed;
+  }
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Change the alarm callback
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used, int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  enterMem();
+  mem.alarmCallback = xCallback;
+  mem.alarmArg = pArg;
+  mem.alarmThreshold = iThreshold;
+  sqlite3_mutex_leave(mem.mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Trigger the alarm 
+*/
+static void sqlite3MemsysAlarm(int nByte){
+  void (*xCallback)(void*,sqlite3_int64,int);
+  sqlite3_int64 nowUsed;
+  void *pArg;
+  if( mem.alarmCallback==0 || mem.alarmBusy  ) return;
+  mem.alarmBusy = 1;
+  xCallback = mem.alarmCallback;
+  nowUsed = mem.nowUsed;
+  pArg = mem.alarmArg;
+  sqlite3_mutex_leave(mem.mutex);
+  xCallback(pArg, nowUsed, nByte);
+  sqlite3_mutex_enter(mem.mutex);
+  mem.alarmBusy = 0;
+}
+
+/*
+** Given an allocation, find the MemBlockHdr for that allocation.
+**
+** This routine checks the guards at either end of the allocation and
+** if they are incorrect it asserts.
+*/
+static struct MemBlockHdr *sqlite3MemsysGetHeader(void *pAllocation){
+  struct MemBlockHdr *p;
+  int *pInt;
+  u8 *pU8;
+  int nReserve;
+
+  p = (struct MemBlockHdr*)pAllocation;
+  p--;
+  assert( p->iForeGuard==FOREGUARD );
+  nReserve = (p->iSize+7)&~7;
+  pInt = (int*)pAllocation;
+  pU8 = (u8*)pAllocation;
+  assert( pInt[nReserve/sizeof(int)]==REARGUARD );
+  assert( (nReserve-0)<=p->iSize || pU8[nReserve-1]==0x65 );
+  assert( (nReserve-1)<=p->iSize || pU8[nReserve-2]==0x65 );
+  assert( (nReserve-2)<=p->iSize || pU8[nReserve-3]==0x65 );
+  return p;
+}
+
+/*
+** Return the number of bytes currently allocated at address p.
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(void *p){
+  struct MemBlockHdr *pHdr;
+  if( !p ){
+    return 0;
+  }
+  pHdr = sqlite3MemsysGetHeader(p);
+  return pHdr->iSize;
+}
+
+/*
+** Allocate nByte bytes of memory.
+*/
+SQLITE_API void *sqlite3_malloc(int nByte){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  int *pInt;
+  void *p = 0;
+  int totalSize;
+
+  if( nByte>0 ){
+    int nReserve;
+    enterMem();
+    assert( mem.disallow==0 );
+    if( mem.alarmCallback!=0 && mem.nowUsed+nByte>=mem.alarmThreshold ){
+      sqlite3MemsysAlarm(nByte);
+    }
+    nReserve = (nByte+7)&~7;
+    if( nReserve/8>NCSIZE-1 ){
+      mem.sizeCnt[NCSIZE-1]++;
+    }else{
+      mem.sizeCnt[nReserve/8]++;
+    }
+    totalSize = nReserve + sizeof(*pHdr) + sizeof(int) +
+                 mem.nBacktrace*sizeof(void*) + mem.nTitle;
+    if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
+      p = 0;
+    }else{
+      p = malloc(totalSize);
+      if( p==0 ){
+        sqlite3MemsysAlarm(nByte);
+        p = malloc(totalSize);
+      }
+    }
+    if( p ){
+      z = p;
+      pBt = (void**)&z[mem.nTitle];
+      pHdr = (struct MemBlockHdr*)&pBt[mem.nBacktrace];
+      pHdr->pNext = 0;
+      pHdr->pPrev = mem.pLast;
+      if( mem.pLast ){
+        mem.pLast->pNext = pHdr;
+      }else{
+        mem.pFirst = pHdr;
+      }
+      mem.pLast = pHdr;
+      pHdr->iForeGuard = FOREGUARD;
+      pHdr->nBacktraceSlots = mem.nBacktrace;
+      pHdr->nTitle = mem.nTitle;
+      if( mem.nBacktrace ){
+        void *aAddr[40];
+        pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
+        memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+	if( mem.xBacktrace ){
+          mem.xBacktrace(nByte, pHdr->nBacktrace-1, &aAddr[1]);
+	}
+      }else{
+        pHdr->nBacktrace = 0;
+      }
+      if( mem.nTitle ){
+        memcpy(z, mem.zTitle, mem.nTitle);
+      }
+      pHdr->iSize = nByte;
+      pInt = (int*)&pHdr[1];
+      pInt[nReserve/sizeof(int)] = REARGUARD;
+      memset(pInt, 0x65, nReserve);
+      mem.nowUsed += nByte;
+      if( mem.nowUsed>mem.mxUsed ){
+        mem.mxUsed = mem.nowUsed;
+      }
+      p = (void*)pInt;
+    }
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  return p; 
+}
+
+/*
+** Free memory.
+*/
+SQLITE_API void sqlite3_free(void *pPrior){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  pHdr = sqlite3MemsysGetHeader(pPrior);
+  pBt = (void**)pHdr;
+  pBt -= pHdr->nBacktraceSlots;
+  sqlite3_mutex_enter(mem.mutex);
+  mem.nowUsed -= pHdr->iSize;
+  if( pHdr->pPrev ){
+    assert( pHdr->pPrev->pNext==pHdr );
+    pHdr->pPrev->pNext = pHdr->pNext;
+  }else{
+    assert( mem.pFirst==pHdr );
+    mem.pFirst = pHdr->pNext;
+  }
+  if( pHdr->pNext ){
+    assert( pHdr->pNext->pPrev==pHdr );
+    pHdr->pNext->pPrev = pHdr->pPrev;
+  }else{
+    assert( mem.pLast==pHdr );
+    mem.pLast = pHdr->pPrev;
+  }
+  z = (char*)pBt;
+  z -= pHdr->nTitle;
+  memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+                  pHdr->iSize + sizeof(int) + pHdr->nTitle);
+  free(z);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** For this debugging implementation, we *always* make a copy of the
+** allocation into a new place in memory.  In this way, if the 
+** higher level code is using pointer to the old allocation, it is 
+** much more likely to break and we are much more liking to find
+** the error.
+*/
+SQLITE_API void *sqlite3_realloc(void *pPrior, int nByte){
+  struct MemBlockHdr *pOldHdr;
+  void *pNew;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nByte);
+  }
+  if( nByte<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  assert( mem.disallow==0 );
+  pOldHdr = sqlite3MemsysGetHeader(pPrior);
+  pNew = sqlite3_malloc(nByte);
+  if( pNew ){
+    memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
+    if( nByte>pOldHdr->iSize ){
+      memset(&((char*)pNew)[pOldHdr->iSize], 0x2b, nByte - pOldHdr->iSize);
+    }
+    sqlite3_free(pPrior);
+  }
+  return pNew;
+}
+
+/*
+** Set the number of backtrace levels kept for each allocation.
+** A value of zero turns of backtracing.  The number is always rounded
+** up to a multiple of 2.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugBacktrace(int depth){
+  if( depth<0 ){ depth = 0; }
+  if( depth>20 ){ depth = 20; }
+  depth = (depth+1)&0xfe;
+  mem.nBacktrace = depth;
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugBacktraceCallback(void (*xBacktrace)(int, int, void **)){
+  mem.xBacktrace = xBacktrace;
+}
+
+/*
+** Set the title string for subsequent allocations.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSettitle(const char *zTitle){
+  int n = strlen(zTitle) + 1;
+  enterMem();
+  if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
+  memcpy(mem.zTitle, zTitle, n);
+  mem.zTitle[n] = 0;
+  mem.nTitle = (n+7)&~7;
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugSync(){
+  struct MemBlockHdr *pHdr;
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    void **pBt = (void**)pHdr;
+    pBt -= pHdr->nBacktraceSlots;
+    mem.xBacktrace(pHdr->iSize, pHdr->nBacktrace-1, &pBt[1]);
+  }
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory 
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugDump(const char *zFilename){
+  FILE *out;
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  int i;
+  out = fopen(zFilename, "w");
+  if( out==0 ){
+    fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                    zFilename);
+    return;
+  }
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    char *z = (char*)pHdr;
+    z -= pHdr->nBacktraceSlots*sizeof(void*) + pHdr->nTitle;
+    fprintf(out, "**** %lld bytes at %p from %s ****\n", 
+            pHdr->iSize, &pHdr[1], pHdr->nTitle ? z : "???");
+    if( pHdr->nBacktrace ){
+      fflush(out);
+      pBt = (void**)pHdr;
+      pBt -= pHdr->nBacktraceSlots;
+      backtrace_symbols_fd(pBt, pHdr->nBacktrace, fileno(out));
+      fprintf(out, "\n");
+    }
+  }
+  fprintf(out, "COUNTS:\n");
+  for(i=0; i<NCSIZE-1; i++){
+    if( mem.sizeCnt[i] ){
+      fprintf(out, "   %3d: %d\n", i*8+8, mem.sizeCnt[i]);
+    }
+  }
+  if( mem.sizeCnt[NCSIZE-1] ){
+    fprintf(out, "  >%3d: %d\n", NCSIZE*8, mem.sizeCnt[NCSIZE-1]);
+  }
+  fclose(out);
+}
+
+/*
+** Return the number of times sqlite3_malloc() has been called.
+*/
+SQLITE_PRIVATE int sqlite3MemdebugMallocCount(){
+  int i;
+  int nTotal = 0;
+  for(i=0; i<NCSIZE; i++){
+    nTotal += mem.sizeCnt[i];
+  }
+  return nTotal;
+}
+
+
+#endif /* SQLITE_MEMDEBUG */
+
+/************** End of mem2.c ************************************************/
+/************** Begin file mem3.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite. 
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc().  All dynamically allocatable memory is
+** contained in a static array, mem.aPool[].  The size of this
+** fixed memory pool is SQLITE_MEMORY_SIZE bytes.
+**
+** This version of the memory allocation subsystem is used if
+** and only if SQLITE_MEMORY_SIZE is defined.
+**
+** $Id: mem3.c,v 1.12 2008/02/19 15:15:16 drh Exp $
+*/
+
+/*
+** This version of the memory allocator is used only when 
+** SQLITE_MEMORY_SIZE is defined.
+*/
+#ifdef SQLITE_MEMORY_SIZE
+
+/*
+** Maximum size (in Mem3Blocks) of a "small" chunk.
+*/
+#define MX_SMALL 10
+
+
+/*
+** Number of freelist hash slots
+*/
+#define N_HASH  61
+
+/*
+** A memory allocation (also called a "chunk") consists of two or 
+** more blocks where each block is 8 bytes.  The first 8 bytes are 
+** a header that is not returned to the user.
+**
+** A chunk is two or more blocks that is either checked out or
+** free.  The first block has format u.hdr.  u.hdr.size4x is 4 times the
+** size of the allocation in blocks if the allocation is free.
+** The u.hdr.size4x&1 bit is true if the chunk is checked out and
+** false if the chunk is on the freelist.  The u.hdr.size4x&2 bit
+** is true if the previous chunk is checked out and false if the
+** previous chunk is free.  The u.hdr.prevSize field is the size of
+** the previous chunk in blocks if the previous chunk is on the
+** freelist. If the previous chunk is checked out, then
+** u.hdr.prevSize can be part of the data for that chunk and should
+** not be read or written.
+**
+** We often identify a chunk by its index in mem.aPool[].  When
+** this is done, the chunk index refers to the second block of
+** the chunk.  In this way, the first chunk has an index of 1.
+** A chunk index of 0 means "no such chunk" and is the equivalent
+** of a NULL pointer.
+**
+** The second block of free chunks is of the form u.list.  The
+** two fields form a double-linked list of chunks of related sizes.
+** Pointers to the head of the list are stored in mem.aiSmall[] 
+** for smaller chunks and mem.aiHash[] for larger chunks.
+**
+** The second block of a chunk is user data if the chunk is checked 
+** out.  If a chunk is checked out, the user data may extend into
+** the u.hdr.prevSize value of the following chunk.
+*/
+typedef struct Mem3Block Mem3Block;
+struct Mem3Block {
+  union {
+    struct {
+      u32 prevSize;   /* Size of previous chunk in Mem3Block elements */
+      u32 size4x;     /* 4x the size of current chunk in Mem3Block elements */
+    } hdr;
+    struct {
+      u32 next;       /* Index in mem.aPool[] of next free chunk */
+      u32 prev;       /* Index in mem.aPool[] of previous free chunk */
+    } list;
+  } u;
+};
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** True if we are evaluating an out-of-memory callback.
+  */
+  int alarmBusy;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+  
+  /*
+  ** The minimum amount of free space that we have seen.
+  */
+  u32 mnMaster;
+
+  /*
+  ** iMaster is the index of the master chunk.  Most new allocations
+  ** occur off of this chunk.  szMaster is the size (in Mem3Blocks)
+  ** of the current master.  iMaster is 0 if there is not master chunk.
+  ** The master chunk is not in either the aiHash[] or aiSmall[].
+  */
+  u32 iMaster;
+  u32 szMaster;
+
+  /*
+  ** Array of lists of free blocks according to the block size 
+  ** for smaller chunks, or a hash on the block size for larger
+  ** chunks.
+  */
+  u32 aiSmall[MX_SMALL-1];   /* For sizes 2 through MX_SMALL, inclusive */
+  u32 aiHash[N_HASH];        /* For sizes MX_SMALL+1 and larger */
+
+  /*
+  ** Memory available for allocation
+  */
+  Mem3Block aPool[SQLITE_MEMORY_SIZE/sizeof(Mem3Block)+2];
+} mem;
+
+/*
+** Unlink the chunk at mem.aPool[i] from list it is currently
+** on.  *pRoot is the list that i is a member of.
+*/
+static void memsys3UnlinkFromList(u32 i, u32 *pRoot){
+  u32 next = mem.aPool[i].u.list.next;
+  u32 prev = mem.aPool[i].u.list.prev;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  if( prev==0 ){
+    *pRoot = next;
+  }else{
+    mem.aPool[prev].u.list.next = next;
+  }
+  if( next ){
+    mem.aPool[next].u.list.prev = prev;
+  }
+  mem.aPool[i].u.list.next = 0;
+  mem.aPool[i].u.list.prev = 0;
+}
+
+/*
+** Unlink the chunk at index i from 
+** whatever list is currently a member of.
+*/
+static void memsys3Unlink(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( (mem.aPool[i-1].u.hdr.size4x & 1)==0 );
+  assert( i>=1 );
+  size = mem.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3UnlinkFromList(i, &mem.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3UnlinkFromList(i, &mem.aiHash[hash]);
+  }
+}
+
+/*
+** Link the chunk at mem.aPool[i] so that is on the list rooted
+** at *pRoot.
+*/
+static void memsys3LinkIntoList(u32 i, u32 *pRoot){
+  assert( sqlite3_mutex_held(mem.mutex) );
+  mem.aPool[i].u.list.next = *pRoot;
+  mem.aPool[i].u.list.prev = 0;
+  if( *pRoot ){
+    mem.aPool[*pRoot].u.list.prev = i;
+  }
+  *pRoot = i;
+}
+
+/*
+** Link the chunk at index i into either the appropriate
+** small chunk list, or into the large chunk hash table.
+*/
+static void memsys3Link(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( i>=1 );
+  assert( (mem.aPool[i-1].u.hdr.size4x & 1)==0 );
+  size = mem.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3LinkIntoList(i, &mem.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3LinkIntoList(i, &mem.aiHash[hash]);
+  }
+}
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+**
+** Also:  Initialize the memory allocation subsystem the first time
+** this routine is called.
+*/
+static void memsys3Enter(void){
+  if( mem.mutex==0 ){
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+    mem.aPool[0].u.hdr.size4x = SQLITE_MEMORY_SIZE/2 + 2;
+    mem.aPool[SQLITE_MEMORY_SIZE/8].u.hdr.prevSize = SQLITE_MEMORY_SIZE/8;
+    mem.aPool[SQLITE_MEMORY_SIZE/8].u.hdr.size4x = 1;
+    mem.iMaster = 1;
+    mem.szMaster = SQLITE_MEMORY_SIZE/8;
+    mem.mnMaster = mem.szMaster;
+  }
+  sqlite3_mutex_enter(mem.mutex);
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 n;
+  memsys3Enter();
+  n = SQLITE_MEMORY_SIZE - mem.szMaster*8;
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 n;
+  memsys3Enter();
+  n = SQLITE_MEMORY_SIZE - mem.mnMaster*8;
+  if( resetFlag ){
+    mem.mnMaster = mem.szMaster;
+  }
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Change the alarm callback.
+**
+** This is a no-op for the static memory allocator.  The purpose
+** of the memory alarm is to support sqlite3_soft_heap_limit().
+** But with this memory allocator, the soft_heap_limit is really
+** a hard limit that is fixed at SQLITE_MEMORY_SIZE.
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  return SQLITE_OK;
+}
+
+/*
+** Called when we are unable to satisfy an allocation of nBytes.
+*/
+static void memsys3OutOfMemory(int nByte){
+  if( !mem.alarmBusy ){
+    mem.alarmBusy = 1;
+    assert( sqlite3_mutex_held(mem.mutex) );
+    sqlite3_mutex_leave(mem.mutex);
+    sqlite3_release_memory(nByte);
+    sqlite3_mutex_enter(mem.mutex);
+    mem.alarmBusy = 0;
+  }
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.  The
+** size returned omits the 8-byte header overhead.  This only
+** works for chunks that are currently checked out.
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(void *p){
+  int iSize = 0;
+  if( p ){
+    Mem3Block *pBlock = (Mem3Block*)p;
+    assert( (pBlock[-1].u.hdr.size4x&1)!=0 );
+    iSize = (pBlock[-1].u.hdr.size4x&~3)*2 - 4;
+  }
+  return iSize;
+}
+
+/*
+** Chunk i is a free chunk that has been unlinked.  Adjust its 
+** size parameters for check-out and return a pointer to the 
+** user portion of the chunk.
+*/
+static void *memsys3Checkout(u32 i, int nBlock){
+  u32 x;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( i>=1 );
+  assert( mem.aPool[i-1].u.hdr.size4x/4==nBlock );
+  assert( mem.aPool[i+nBlock-1].u.hdr.prevSize==nBlock );
+  x = mem.aPool[i-1].u.hdr.size4x;
+  mem.aPool[i-1].u.hdr.size4x = nBlock*4 | 1 | (x&2);
+  mem.aPool[i+nBlock-1].u.hdr.prevSize = nBlock;
+  mem.aPool[i+nBlock-1].u.hdr.size4x |= 2;
+  return &mem.aPool[i];
+}
+
+/*
+** Carve a piece off of the end of the mem.iMaster free chunk.
+** Return a pointer to the new allocation.  Or, if the master chunk
+** is not large enough, return 0.
+*/
+static void *memsys3FromMaster(int nBlock){
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( mem.szMaster>=nBlock );
+  if( nBlock>=mem.szMaster-1 ){
+    /* Use the entire master */
+    void *p = memsys3Checkout(mem.iMaster, mem.szMaster);
+    mem.iMaster = 0;
+    mem.szMaster = 0;
+    mem.mnMaster = 0;
+    return p;
+  }else{
+    /* Split the master block.  Return the tail. */
+    u32 newi, x;
+    newi = mem.iMaster + mem.szMaster - nBlock;
+    assert( newi > mem.iMaster+1 );
+    mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = nBlock;
+    mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.size4x |= 2;
+    mem.aPool[newi-1].u.hdr.size4x = nBlock*4 + 1;
+    mem.szMaster -= nBlock;
+    mem.aPool[newi-1].u.hdr.prevSize = mem.szMaster;
+    x = mem.aPool[mem.iMaster-1].u.hdr.size4x & 2;
+    mem.aPool[mem.iMaster-1].u.hdr.size4x = mem.szMaster*4 | x;
+    if( mem.szMaster < mem.mnMaster ){
+      mem.mnMaster = mem.szMaster;
+    }
+    return (void*)&mem.aPool[newi];
+  }
+}
+
+/*
+** *pRoot is the head of a list of free chunks of the same size
+** or same size hash.  In other words, *pRoot is an entry in either
+** mem.aiSmall[] or mem.aiHash[].  
+**
+** This routine examines all entries on the given list and tries
+** to coalesce each entries with adjacent free chunks.  
+**
+** If it sees a chunk that is larger than mem.iMaster, it replaces 
+** the current mem.iMaster with the new larger chunk.  In order for
+** this mem.iMaster replacement to work, the master chunk must be
+** linked into the hash tables.  That is not the normal state of
+** affairs, of course.  The calling routine must link the master
+** chunk before invoking this routine, then must unlink the (possibly
+** changed) master chunk once this routine has finished.
+*/
+static void memsys3Merge(u32 *pRoot){
+  u32 iNext, prev, size, i, x;
+
+  assert( sqlite3_mutex_held(mem.mutex) );
+  for(i=*pRoot; i>0; i=iNext){
+    iNext = mem.aPool[i].u.list.next;
+    size = mem.aPool[i-1].u.hdr.size4x;
+    assert( (size&1)==0 );
+    if( (size&2)==0 ){
+      memsys3UnlinkFromList(i, pRoot);
+      assert( i > mem.aPool[i-1].u.hdr.prevSize );
+      prev = i - mem.aPool[i-1].u.hdr.prevSize;
+      if( prev==iNext ){
+        iNext = mem.aPool[prev].u.list.next;
+      }
+      memsys3Unlink(prev);
+      size = i + size/4 - prev;
+      x = mem.aPool[prev-1].u.hdr.size4x & 2;
+      mem.aPool[prev-1].u.hdr.size4x = size*4 | x;
+      mem.aPool[prev+size-1].u.hdr.prevSize = size;
+      memsys3Link(prev);
+      i = prev;
+    }else{
+      size /= 4;
+    }
+    if( size>mem.szMaster ){
+      mem.iMaster = i;
+      mem.szMaster = size;
+    }
+  }
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.
+*/
+static void *memsys3Malloc(int nByte){
+  u32 i;
+  int nBlock;
+  int toFree;
+
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( sizeof(Mem3Block)==8 );
+  if( nByte<=12 ){
+    nBlock = 2;
+  }else{
+    nBlock = (nByte + 11)/8;
+  }
+  assert( nBlock >= 2 );
+
+  /* STEP 1:
+  ** Look for an entry of the correct size in either the small
+  ** chunk table or in the large chunk hash table.  This is
+  ** successful most of the time (about 9 times out of 10).
+  */
+  if( nBlock <= MX_SMALL ){
+    i = mem.aiSmall[nBlock-2];
+    if( i>0 ){
+      memsys3UnlinkFromList(i, &mem.aiSmall[nBlock-2]);
+      return memsys3Checkout(i, nBlock);
+    }
+  }else{
+    int hash = nBlock % N_HASH;
+    for(i=mem.aiHash[hash]; i>0; i=mem.aPool[i].u.list.next){
+      if( mem.aPool[i-1].u.hdr.size4x/4==nBlock ){
+        memsys3UnlinkFromList(i, &mem.aiHash[hash]);
+        return memsys3Checkout(i, nBlock);
+      }
+    }
+  }
+
+  /* STEP 2:
+  ** Try to satisfy the allocation by carving a piece off of the end
+  ** of the master chunk.  This step usually works if step 1 fails.
+  */
+  if( mem.szMaster>=nBlock ){
+    return memsys3FromMaster(nBlock);
+  }
+
+
+  /* STEP 3:  
+  ** Loop through the entire memory pool.  Coalesce adjacent free
+  ** chunks.  Recompute the master chunk as the largest free chunk.
+  ** Then try again to satisfy the allocation by carving a piece off
+  ** of the end of the master chunk.  This step happens very
+  ** rarely (we hope!)
+  */
+  for(toFree=nBlock*16; toFree<SQLITE_MEMORY_SIZE*2; toFree *= 2){
+    memsys3OutOfMemory(toFree);
+    if( mem.iMaster ){
+      memsys3Link(mem.iMaster);
+      mem.iMaster = 0;
+      mem.szMaster = 0;
+    }
+    for(i=0; i<N_HASH; i++){
+      memsys3Merge(&mem.aiHash[i]);
+    }
+    for(i=0; i<MX_SMALL-1; i++){
+      memsys3Merge(&mem.aiSmall[i]);
+    }
+    if( mem.szMaster ){
+      memsys3Unlink(mem.iMaster);
+      if( mem.szMaster>=nBlock ){
+        return memsys3FromMaster(nBlock);
+      }
+    }
+  }
+
+  /* If none of the above worked, then we fail. */
+  return 0;
+}
+
+/*
+** Free an outstanding memory allocation.
+*/
+void memsys3Free(void *pOld){
+  Mem3Block *p = (Mem3Block*)pOld;
+  int i;
+  u32 size, x;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( p>mem.aPool && p<&mem.aPool[SQLITE_MEMORY_SIZE/8] );
+  i = p - mem.aPool;
+  assert( (mem.aPool[i-1].u.hdr.size4x&1)==1 );
+  size = mem.aPool[i-1].u.hdr.size4x/4;
+  assert( i+size<=SQLITE_MEMORY_SIZE/8+1 );
+  mem.aPool[i-1].u.hdr.size4x &= ~1;
+  mem.aPool[i+size-1].u.hdr.prevSize = size;
+  mem.aPool[i+size-1].u.hdr.size4x &= ~2;
+  memsys3Link(i);
+
+  /* Try to expand the master using the newly freed chunk */
+  if( mem.iMaster ){
+    while( (mem.aPool[mem.iMaster-1].u.hdr.size4x&2)==0 ){
+      size = mem.aPool[mem.iMaster-1].u.hdr.prevSize;
+      mem.iMaster -= size;
+      mem.szMaster += size;
+      memsys3Unlink(mem.iMaster);
+      x = mem.aPool[mem.iMaster-1].u.hdr.size4x & 2;
+      mem.aPool[mem.iMaster-1].u.hdr.size4x = mem.szMaster*4 | x;
+      mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = mem.szMaster;
+    }
+    x = mem.aPool[mem.iMaster-1].u.hdr.size4x & 2;
+    while( (mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.size4x&1)==0 ){
+      memsys3Unlink(mem.iMaster+mem.szMaster);
+      mem.szMaster += mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.size4x/4;
+      mem.aPool[mem.iMaster-1].u.hdr.size4x = mem.szMaster*4 | x;
+      mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = mem.szMaster;
+    }
+  }
+}
+
+/*
+** Allocate nBytes of memory
+*/
+SQLITE_API void *sqlite3_malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    memsys3Enter();
+    p = memsys3Malloc(nBytes);
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  return (void*)p; 
+}
+
+/*
+** Free memory.
+*/
+SQLITE_API void sqlite3_free(void *pPrior){
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  sqlite3_mutex_enter(mem.mutex);
+  memsys3Free(pPrior);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+SQLITE_API void *sqlite3_realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  assert( mem.mutex!=0 );
+  nOld = sqlite3MallocSize(pPrior);
+  if( nBytes<=nOld && nBytes>=nOld-128 ){
+    return pPrior;
+  }
+  sqlite3_mutex_enter(mem.mutex);
+  p = memsys3Malloc(nBytes);
+  if( p ){
+    if( nOld<nBytes ){
+      memcpy(p, pPrior, nOld);
+    }else{
+      memcpy(p, pPrior, nBytes);
+    }
+    memsys3Free(pPrior);
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return p;
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory 
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugDump(const char *zFilename){
+#ifdef SQLITE_DEBUG
+  FILE *out;
+  int i, j;
+  u32 size;
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys3Enter();
+  fprintf(out, "CHUNKS:\n");
+  for(i=1; i<=SQLITE_MEMORY_SIZE/8; i+=size/4){
+    size = mem.aPool[i-1].u.hdr.size4x;
+    if( size/4<=1 ){
+      fprintf(out, "%p size error\n", &mem.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( (size&1)==0 && mem.aPool[i+size/4-1].u.hdr.prevSize!=size/4 ){
+      fprintf(out, "%p tail size does not match\n", &mem.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( ((mem.aPool[i+size/4-1].u.hdr.size4x&2)>>1)!=(size&1) ){
+      fprintf(out, "%p tail checkout bit is incorrect\n", &mem.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( size&1 ){
+      fprintf(out, "%p %6d bytes checked out\n", &mem.aPool[i], (size/4)*8-8);
+    }else{
+      fprintf(out, "%p %6d bytes free%s\n", &mem.aPool[i], (size/4)*8-8,
+                  i==mem.iMaster ? " **master**" : "");
+    }
+  }
+  for(i=0; i<MX_SMALL-1; i++){
+    if( mem.aiSmall[i]==0 ) continue;
+    fprintf(out, "small(%2d):", i);
+    for(j = mem.aiSmall[i]; j>0; j=mem.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem.aPool[j],
+              (mem.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n"); 
+  }
+  for(i=0; i<N_HASH; i++){
+    if( mem.aiHash[i]==0 ) continue;
+    fprintf(out, "hash(%2d):", i);
+    for(j = mem.aiHash[i]; j>0; j=mem.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem.aPool[j],
+              (mem.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n"); 
+  }
+  fprintf(out, "master=%d\n", mem.iMaster);
+  fprintf(out, "nowUsed=%d\n", SQLITE_MEMORY_SIZE - mem.szMaster*8);
+  fprintf(out, "mxUsed=%d\n", SQLITE_MEMORY_SIZE - mem.mnMaster*8);
+  sqlite3_mutex_leave(mem.mutex);
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+#endif
+}
+
+
+#endif /* !SQLITE_MEMORY_SIZE */
+
+/************** End of mem3.c ************************************************/
+/************** Begin file mem5.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite. 
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc().  All dynamically allocatable memory is
+** contained in a static array, mem.aPool[].  The size of this
+** fixed memory pool is SQLITE_POW2_MEMORY_SIZE bytes.
+**
+** This version of the memory allocation subsystem is used if
+** and only if SQLITE_POW2_MEMORY_SIZE is defined.
+**
+** $Id: mem5.c,v 1.4 2008/02/19 15:15:16 drh Exp $
+*/
+
+/*
+** This version of the memory allocator is used only when 
+** SQLITE_POW2_MEMORY_SIZE is defined.
+*/
+#ifdef SQLITE_POW2_MEMORY_SIZE
+
+/*
+** Log2 of the minimum size of an allocation.  For example, if
+** 4 then all allocations will be rounded up to at least 16 bytes.
+** If 5 then all allocations will be rounded up to at least 32 bytes.
+*/
+#ifndef SQLITE_POW2_LOGMIN
+# define SQLITE_POW2_LOGMIN 6
+#endif
+#define POW2_MIN (1<<SQLITE_POW2_LOGMIN)
+
+/*
+** Log2 of the maximum size of an allocation.
+*/
+#ifndef SQLITE_POW2_LOGMAX
+# define SQLITE_POW2_LOGMAX 18
+#endif
+#define POW2_MAX (((unsigned int)1)<<SQLITE_POW2_LOGMAX)
+
+/*
+** Number of distinct allocation sizes.
+*/
+#define NSIZE (SQLITE_POW2_LOGMAX - SQLITE_POW2_LOGMIN + 1)
+
+/*
+** A minimum allocation is an instance of the following structure.
+** Larger allocations are an array of these structures where the
+** size of the array is a power of 2.
+*/
+typedef struct Mem5Block Mem5Block;
+struct Mem5Block {
+  union {
+    char aData[POW2_MIN];
+    struct {
+      int next;       /* Index in mem.aPool[] of next free chunk */
+      int prev;       /* Index in mem.aPool[] of previous free chunk */
+    } list;
+  } u;
+};
+
+/*
+** Number of blocks of memory available for allocation.
+*/
+#define NBLOCK (SQLITE_POW2_MEMORY_SIZE/POW2_MIN)
+
+/*
+** The size in blocks of an POW2_MAX allocation
+*/
+#define SZ_MAX (1<<(NSIZE-1))
+
+/*
+** Masks used for mem.aCtrl[] elements.
+*/
+#define CTRL_LOGSIZE  0x1f    /* Log2 Size of this block relative to POW2_MIN */
+#define CTRL_FREE     0x20    /* True if not checked out */
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** The alarm callback and its arguments.  The mem.mutex lock will
+  ** be held while the callback is running.  Recursive calls into
+  ** the memory subsystem are allowed, but no new callbacks will be
+  ** issued.  The alarmBusy variable is set to prevent recursive
+  ** callbacks.
+  */
+  sqlite3_int64 alarmThreshold;
+  void (*alarmCallback)(void*, sqlite3_int64,int);
+  void *alarmArg;
+  int alarmBusy;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+  /*
+  ** Performance statistics
+  */
+  u64 nAlloc;         /* Total number of calls to malloc */
+  u64 totalAlloc;     /* Total of all malloc calls - includes internal frag */
+  u64 totalExcess;    /* Total internal fragmentation */
+  u32 currentOut;     /* Current checkout, including internal fragmentation */
+  u32 currentCount;   /* Current number of distinct checkouts */
+  u32 maxOut;         /* Maximum instantaneous currentOut */
+  u32 maxCount;       /* Maximum instantaneous currentCount */
+  u32 maxRequest;     /* Largest allocation (exclusive of internal frag) */
+  
+  /*
+  ** Lists of free blocks of various sizes.
+  */
+  int aiFreelist[NSIZE];
+
+  /*
+  ** Space for tracking which blocks are checked out and the size
+  ** of each block.  One byte per block.
+  */
+  u8 aCtrl[NBLOCK];
+
+  /*
+  ** Memory available for allocation
+  */
+  Mem5Block aPool[NBLOCK];
+} mem;
+
+/*
+** Unlink the chunk at mem.aPool[i] from list it is currently
+** on.  It should be found on mem.aiFreelist[iLogsize].
+*/
+static void memsys5Unlink(int i, int iLogsize){
+  int next, prev;
+  assert( i>=0 && i<NBLOCK );
+  assert( iLogsize>=0 && iLogsize<NSIZE );
+  assert( (mem.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+  assert( sqlite3_mutex_held(mem.mutex) );
+
+  next = mem.aPool[i].u.list.next;
+  prev = mem.aPool[i].u.list.prev;
+  if( prev<0 ){
+    mem.aiFreelist[iLogsize] = next;
+  }else{
+    mem.aPool[prev].u.list.next = next;
+  }
+  if( next>=0 ){
+    mem.aPool[next].u.list.prev = prev;
+  }
+}
+
+/*
+** Link the chunk at mem.aPool[i] so that is on the iLogsize
+** free list.
+*/
+static void memsys5Link(int i, int iLogsize){
+  int x;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( i>=0 && i<NBLOCK );
+  assert( iLogsize>=0 && iLogsize<NSIZE );
+  assert( (mem.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+
+  mem.aPool[i].u.list.next = x = mem.aiFreelist[iLogsize];
+  mem.aPool[i].u.list.prev = -1;
+  if( x>=0 ){
+    assert( x<NBLOCK );
+    mem.aPool[x].u.list.prev = i;
+  }
+  mem.aiFreelist[iLogsize] = i;
+}
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+**
+** Also:  Initialize the memory allocation subsystem the first time
+** this routine is called.
+*/
+static void memsys5Enter(void){
+  if( mem.mutex==0 ){
+    int i;
+    assert( sizeof(Mem5Block)==POW2_MIN );
+    assert( (SQLITE_POW2_MEMORY_SIZE % POW2_MAX)==0 );
+    assert( SQLITE_POW2_MEMORY_SIZE>=POW2_MAX );
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+    sqlite3_mutex_enter(mem.mutex);
+    for(i=0; i<NSIZE; i++) mem.aiFreelist[i] = -1;
+    for(i=0; i<=NBLOCK-SZ_MAX; i += SZ_MAX){
+      mem.aCtrl[i] = (NSIZE-1) | CTRL_FREE;
+      memsys5Link(i, NSIZE-1);
+    }
+  }else{
+    sqlite3_mutex_enter(mem.mutex);
+  }
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  return mem.currentOut;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 n;
+  memsys5Enter();
+  n = mem.maxOut;
+  if( resetFlag ){
+    mem.maxOut = mem.currentOut;
+  }
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+
+/*
+** Trigger the alarm 
+*/
+static void memsys5Alarm(int nByte){
+  void (*xCallback)(void*,sqlite3_int64,int);
+  sqlite3_int64 nowUsed;
+  void *pArg;
+  if( mem.alarmCallback==0 || mem.alarmBusy  ) return;
+  mem.alarmBusy = 1;
+  xCallback = mem.alarmCallback;
+  nowUsed = mem.currentOut;
+  pArg = mem.alarmArg;
+  sqlite3_mutex_leave(mem.mutex);
+  xCallback(pArg, nowUsed, nByte);
+  sqlite3_mutex_enter(mem.mutex);
+  mem.alarmBusy = 0;
+}
+
+/*
+** Change the alarm callback.
+**
+** This is a no-op for the static memory allocator.  The purpose
+** of the memory alarm is to support sqlite3_soft_heap_limit().
+** But with this memory allocator, the soft_heap_limit is really
+** a hard limit that is fixed at SQLITE_POW2_MEMORY_SIZE.
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  memsys5Enter();
+  mem.alarmCallback = xCallback;
+  mem.alarmArg = pArg;
+  mem.alarmThreshold = iThreshold;
+  sqlite3_mutex_leave(mem.mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.  The
+** size returned omits the 8-byte header overhead.  This only
+** works for chunks that are currently checked out.
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(void *p){
+  int iSize = 0;
+  if( p ){
+    int i = ((Mem5Block*)p) - mem.aPool;
+    assert( i>=0 && i<NBLOCK );
+    iSize = 1 << ((mem.aCtrl[i]&CTRL_LOGSIZE) + SQLITE_POW2_LOGMIN);
+  }
+  return iSize;
+}
+
+/*
+** Find the first entry on the freelist iLogsize.  Unlink that
+** entry and return its index. 
+*/
+static int memsys5UnlinkFirst(int iLogsize){
+  int i;
+  int iFirst;
+
+  assert( iLogsize>=0 && iLogsize<NSIZE );
+  i = iFirst = mem.aiFreelist[iLogsize];
+  assert( iFirst>=0 );
+  while( i>0 ){
+    if( i<iFirst ) iFirst = i;
+    i = mem.aPool[i].u.list.next;
+  }
+  memsys5Unlink(iFirst, iLogsize);
+  return iFirst;
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.
+*/
+static void *memsys5Malloc(int nByte){
+  int i;           /* Index of a mem.aPool[] slot */
+  int iBin;        /* Index into mem.aiFreelist[] */
+  int iFullSz;     /* Size of allocation rounded up to power of 2 */
+  int iLogsize;    /* Log2 of iFullSz/POW2_MIN */
+
+  assert( sqlite3_mutex_held(mem.mutex) );
+
+  /* Keep track of the maximum allocation request.  Even unfulfilled
+  ** requests are counted */
+  if( nByte>mem.maxRequest ){
+    mem.maxRequest = nByte;
+  }
+
+  /* Simulate a memory allocation fault */
+  if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ) return 0;
+
+  /* Round nByte up to the next valid power of two */
+  if( nByte>POW2_MAX ) return 0;
+  for(iFullSz=POW2_MIN, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}
+
+  /* If we will be over the memory alarm threshold after this allocation,
+  ** then trigger the memory overflow alarm */
+  if( mem.alarmCallback!=0 && mem.currentOut+iFullSz>=mem.alarmThreshold ){
+    memsys5Alarm(iFullSz);
+  }
+
+  /* Make sure mem.aiFreelist[iLogsize] contains at least one free
+  ** block.  If not, then split a block of the next larger power of
+  ** two in order to create a new free block of size iLogsize.
+  */
+  for(iBin=iLogsize; mem.aiFreelist[iBin]<0 && iBin<NSIZE; iBin++){}
+  if( iBin>=NSIZE ) return 0;
+  i = memsys5UnlinkFirst(iBin);
+  while( iBin>iLogsize ){
+    int newSize;
+
+    iBin--;
+    newSize = 1 << iBin;
+    mem.aCtrl[i+newSize] = CTRL_FREE | iBin;
+    memsys5Link(i+newSize, iBin);
+  }
+  mem.aCtrl[i] = iLogsize;
+
+  /* Update allocator performance statistics. */
+  mem.nAlloc++;
+  mem.totalAlloc += iFullSz;
+  mem.totalExcess += iFullSz - nByte;
+  mem.currentCount++;
+  mem.currentOut += iFullSz;
+  if( mem.maxCount<mem.currentCount ) mem.maxCount = mem.currentCount;
+  if( mem.maxOut<mem.currentOut ) mem.maxOut = mem.currentOut;
+
+  /* Return a pointer to the allocated memory. */
+  return (void*)&mem.aPool[i];
+}
+
+/*
+** Free an outstanding memory allocation.
+*/
+void memsys5Free(void *pOld){
+  u32 size, iLogsize;
+  int i;
+
+  i = ((Mem5Block*)pOld) - mem.aPool;
+  assert( sqlite3_mutex_held(mem.mutex) );
+  assert( i>=0 && i<NBLOCK );
+  assert( (mem.aCtrl[i] & CTRL_FREE)==0 );
+  iLogsize = mem.aCtrl[i] & CTRL_LOGSIZE;
+  size = 1<<iLogsize;
+  assert( i+size-1<NBLOCK );
+  mem.aCtrl[i] |= CTRL_FREE;
+  mem.aCtrl[i+size-1] |= CTRL_FREE;
+  assert( mem.currentCount>0 );
+  assert( mem.currentOut>=0 );
+  mem.currentCount--;
+  mem.currentOut -= size*POW2_MIN;
+  assert( mem.currentOut>0 || mem.currentCount==0 );
+  assert( mem.currentCount>0 || mem.currentOut==0 );
+
+  mem.aCtrl[i] = CTRL_FREE | iLogsize;
+  while( iLogsize<NSIZE-1 ){
+    int iBuddy;
+
+    if( (i>>iLogsize) & 1 ){
+      iBuddy = i - size;
+    }else{
+      iBuddy = i + size;
+    }
+    assert( iBuddy>=0 && iBuddy<NBLOCK );
+    if( mem.aCtrl[iBuddy]!=(CTRL_FREE | iLogsize) ) break;
+    memsys5Unlink(iBuddy, iLogsize);
+    iLogsize++;
+    if( iBuddy<i ){
+      mem.aCtrl[iBuddy] = CTRL_FREE | iLogsize;
+      mem.aCtrl[i] = 0;
+      i = iBuddy;
+    }else{
+      mem.aCtrl[i] = CTRL_FREE | iLogsize;
+      mem.aCtrl[iBuddy] = 0;
+    }
+    size *= 2;
+  }
+  memsys5Link(i, iLogsize);
+}
+
+/*
+** Allocate nBytes of memory
+*/
+SQLITE_API void *sqlite3_malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    memsys5Enter();
+    p = memsys5Malloc(nBytes);
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  return (void*)p; 
+}
+
+/*
+** Free memory.
+*/
+SQLITE_API void sqlite3_free(void *pPrior){
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  sqlite3_mutex_enter(mem.mutex);
+  memsys5Free(pPrior);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+SQLITE_API void *sqlite3_realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  assert( mem.mutex!=0 );
+  nOld = sqlite3MallocSize(pPrior);
+  if( nBytes<=nOld ){
+    return pPrior;
+  }
+  sqlite3_mutex_enter(mem.mutex);
+  p = memsys5Malloc(nBytes);
+  if( p ){
+    memcpy(p, pPrior, nOld);
+    memsys5Free(pPrior);
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return p;
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory 
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugDump(const char *zFilename){
+#ifdef SQLITE_DEBUG
+  FILE *out;
+  int i, j, n;
+
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys5Enter();
+  for(i=0; i<NSIZE; i++){
+    for(n=0, j=mem.aiFreelist[i]; j>=0; j = mem.aPool[j].u.list.next, n++){}
+    fprintf(out, "freelist items of size %d: %d\n", POW2_MIN << i, n);
+  }
+  fprintf(out, "mem.nAlloc       = %llu\n", mem.nAlloc);
+  fprintf(out, "mem.totalAlloc   = %llu\n", mem.totalAlloc);
+  fprintf(out, "mem.totalExcess  = %llu\n", mem.totalExcess);
+  fprintf(out, "mem.currentOut   = %u\n", mem.currentOut);
+  fprintf(out, "mem.currentCount = %u\n", mem.currentCount);
+  fprintf(out, "mem.maxOut       = %u\n", mem.maxOut);
+  fprintf(out, "mem.maxCount     = %u\n", mem.maxCount);
+  fprintf(out, "mem.maxRequest   = %u\n", mem.maxRequest);
+  sqlite3_mutex_leave(mem.mutex);
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+#endif
+}
+
+
+#endif /* !SQLITE_POW2_MEMORY_SIZE */
+
+/************** End of mem5.c ************************************************/
+/************** Begin file mutex.c *******************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes.
+**
+** The implementation in this file does not provide any mutual
+** exclusion and is thus suitable for use only in applications
+** that use SQLite in a single thread.  But this implementation
+** does do a lot of error checking on mutexes to make sure they
+** are called correctly and at appropriate times.  Hence, this
+** implementation is suitable for testing.
+** debugging purposes
+**
+** $Id: mutex.c,v 1.17 2008/03/26 18:34:43 danielk1977 Exp $
+*/
+
+#ifdef SQLITE_MUTEX_NOOP_DEBUG
+/*
+** In this implementation, mutexes do not provide any mutual exclusion.
+** But the error checking is provided.  This implementation is useful
+** for test purposes.
+*/
+
+/*
+** The mutex object
+*/
+struct sqlite3_mutex {
+  int id;     /* The mutex type */
+  int cnt;    /* Number of entries without a matching leave */
+};
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated. 
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int id){
+  static sqlite3_mutex aStatic[6];
+  sqlite3_mutex *pNew = 0;
+  switch( id ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      pNew = sqlite3_malloc(sizeof(*pNew));
+      if( pNew ){
+        pNew->id = id;
+        pNew->cnt = 0;
+      }
+      break;
+    }
+    default: {
+      assert( id-2 >= 0 );
+      assert( id-2 < sizeof(aStatic)/sizeof(aStatic[0]) );
+      pNew = &aStatic[id-2];
+      pNew->id = id;
+      break;
+    }
+  }
+  return pNew;
+}
+
+/*
+** This routine deallocates a previously allocated mutex.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  assert( p );
+  assert( p->cnt==0 );
+  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
+  sqlite3_free(p);
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  p->cnt++;
+}
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  p->cnt++;
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  assert( p );
+  assert( sqlite3_mutex_held(p) );
+  p->cnt--;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+}
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+  return p==0 || p->cnt>0;
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+  return p==0 || p->cnt==0;
+}
+#endif /* SQLITE_MUTEX_NOOP_DEBUG */
+
+/************** End of mutex.c ***********************************************/
+/************** Begin file mutex_os2.c ***************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for OS/2
+**
+** $Id: mutex_os2.c,v 1.6 2008/03/26 18:34:43 danielk1977 Exp $
+*/
+
+/*
+** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
+** See the mutex.h file for details.
+*/
+#ifdef SQLITE_MUTEX_OS2
+
+/********************** OS/2 Mutex Implementation **********************
+**
+** This implementation of mutexes is built using the OS/2 API.
+*/
+
+/*
+** The mutex object
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  HMTX mutex;       /* Mutex controlling the lock */
+  int  id;          /* Mutex type */
+  int  nRef;        /* Number of references */
+  TID  owner;       /* Thread holding this mutex */
+};
+
+#define OS2_MUTEX_INITIALIZER   0,0,0,0
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated. 
+** SQLite will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST               0
+** <li>  SQLITE_MUTEX_RECURSIVE          1
+** <li>  SQLITE_MUTEX_STATIC_MASTER      2
+** <li>  SQLITE_MUTEX_STATIC_MEM         3
+** <li>  SQLITE_MUTEX_STATIC_PRNG        4
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Three static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int iType){
+  sqlite3_mutex *p = NULL;
+  switch( iType ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        p->id = iType;
+        if( DosCreateMutexSem( 0, &p->mutex, 0, FALSE ) != NO_ERROR ){
+          sqlite3_free( p );
+          p = NULL;
+        }
+      }
+      break;
+    }
+    default: {
+      static volatile int isInit = 0;
+      static sqlite3_mutex staticMutexes[] = {
+        { OS2_MUTEX_INITIALIZER, },
+        { OS2_MUTEX_INITIALIZER, },
+        { OS2_MUTEX_INITIALIZER, },
+        { OS2_MUTEX_INITIALIZER, },
+        { OS2_MUTEX_INITIALIZER, },
+        { OS2_MUTEX_INITIALIZER, },
+      };
+      if ( !isInit ){
+        APIRET rc;
+        PTIB ptib;
+        PPIB ppib;
+        HMTX mutex;
+        char name[32];
+        DosGetInfoBlocks( &ptib, &ppib );
+        sqlite3_snprintf( sizeof(name), name, "\\SEM32\\SQLITE%04x",
+                          ppib->pib_ulpid );
+        while( !isInit ){
+          mutex = 0;
+          rc = DosCreateMutexSem( name, &mutex, 0, FALSE);
+          if( rc == NO_ERROR ){
+            int i;
+            if( !isInit ){
+              for( i = 0; i < sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++ ){
+                DosCreateMutexSem( 0, &staticMutexes[i].mutex, 0, FALSE );
+              }
+              isInit = 1;
+            }
+            DosCloseMutexSem( mutex );
+          }else if( rc == ERROR_DUPLICATE_NAME ){
+            DosSleep( 1 );
+          }else{
+            return p;
+          }
+        }
+      }
+      assert( iType-2 >= 0 );
+      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
+      p = &staticMutexes[iType-2];
+      p->id = iType;
+      break;
+    }
+  }
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously allocated mutex.
+** SQLite is careful to deallocate every mutex that it allocates.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  assert( p );
+  assert( p->nRef==0 );
+  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
+  DosCloseMutexSem( p->mutex );
+  sqlite3_free( p );
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  TID tid;
+  PID holder1;
+  ULONG holder2;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  DosRequestMutexSem(p->mutex, SEM_INDEFINITE_WAIT);
+  DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
+  p->owner = tid;
+  p->nRef++;
+}
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  int rc;
+  TID tid;
+  PID holder1;
+  ULONG holder2;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  if( DosRequestMutexSem(p->mutex, SEM_IMMEDIATE_RETURN) == NO_ERROR) {
+    DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
+    p->owner = tid;
+    p->nRef++;
+    rc = SQLITE_OK;
+  } else {
+    rc = SQLITE_BUSY;
+  }
+
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  TID tid;
+  PID holder1;
+  ULONG holder2;
+  assert( p->nRef>0 );
+  DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
+  assert( p->owner==tid );
+  p->nRef--;
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+  DosReleaseMutexSem(p->mutex);
+}
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+  TID tid;
+  PID pid;
+  ULONG ulCount;
+  PTIB ptib;
+  if( p!=0 ) {
+    DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
+  } else {
+    DosGetInfoBlocks(&ptib, NULL);
+    tid = ptib->tib_ptib2->tib2_ultid;
+  }
+  return p==0 || (p->nRef!=0 && p->owner==tid);
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+  TID tid;
+  PID pid;
+  ULONG ulCount;
+  PTIB ptib;
+  if( p!= 0 ) {
+    DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
+  } else {
+    DosGetInfoBlocks(&ptib, NULL);
+    tid = ptib->tib_ptib2->tib2_ultid;
+  }
+  return p==0 || p->nRef==0 || p->owner!=tid;
+}
+#endif /* SQLITE_MUTEX_OS2 */
+
+/************** End of mutex_os2.c *******************************************/
+/************** Begin file mutex_unix.c **************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for pthreads
+**
+** $Id: mutex_unix.c,v 1.7 2008/03/29 12:47:27 rse Exp $
+*/
+
+/*
+** The code in this file is only used if we are compiling threadsafe
+** under unix with pthreads.
+**
+** Note that this implementation requires a version of pthreads that
+** supports recursive mutexes.
+*/
+#ifdef SQLITE_MUTEX_PTHREADS
+
+#include <pthread.h>
+
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  pthread_mutex_t mutex;     /* Mutex controlling the lock */
+  int id;                    /* Mutex type */
+  int nRef;                  /* Number of entrances */
+  pthread_t owner;           /* Thread that is within this mutex */
+#ifdef SQLITE_DEBUG
+  int trace;                 /* True to trace changes */
+#endif
+};
+#ifdef SQLITE_DEBUG
+#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0, 0 }
+#else
+#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0 }
+#endif
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MASTER
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_MEM2
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Three static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static 
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int iType){
+  static sqlite3_mutex staticMutexes[] = {
+    SQLITE3_MUTEX_INITIALIZER,
+    SQLITE3_MUTEX_INITIALIZER,
+    SQLITE3_MUTEX_INITIALIZER,
+    SQLITE3_MUTEX_INITIALIZER,
+    SQLITE3_MUTEX_INITIALIZER,
+    SQLITE3_MUTEX_INITIALIZER
+  };
+  sqlite3_mutex *p;
+  switch( iType ){
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+        /* If recursive mutexes are not available, we will have to
+        ** build our own.  See below. */
+        pthread_mutex_init(&p->mutex, 0);
+#else
+        /* Use a recursive mutex if it is available */
+        pthread_mutexattr_t recursiveAttr;
+        pthread_mutexattr_init(&recursiveAttr);
+        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
+        pthread_mutex_init(&p->mutex, &recursiveAttr);
+        pthread_mutexattr_destroy(&recursiveAttr);
+#endif
+        p->id = iType;
+      }
+      break;
+    }
+    case SQLITE_MUTEX_FAST: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        p->id = iType;
+        pthread_mutex_init(&p->mutex, 0);
+      }
+      break;
+    }
+    default: {
+      assert( iType-2 >= 0 );
+      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
+      p = &staticMutexes[iType-2];
+      p->id = iType;
+      break;
+    }
+  }
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  assert( p );
+  assert( p->nRef==0 );
+  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
+  pthread_mutex_destroy(&p->mutex);
+  sqlite3_free(p);
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that 
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+    }else{
+      pthread_mutex_lock(&p->mutex);
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  pthread_mutex_lock(&p->mutex);
+  p->owner = pthread_self();
+  p->nRef++;
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  int rc;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that 
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+      rc = SQLITE_OK;
+    }else if( pthread_mutex_lock(&p->mutex)==0 ){
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+      rc = SQLITE_OK;
+    }else{
+      rc = SQLITE_BUSY;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  if( pthread_mutex_trylock(&p->mutex)==0 ){
+    p->owner = pthread_self();
+    p->nRef++;
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_BUSY;
+  }
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK && p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  assert( p );
+  assert( sqlite3_mutex_held(p) );
+  p->nRef--;
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  if( p->nRef==0 ){
+    pthread_mutex_unlock(&p->mutex);
+  }
+#else
+  pthread_mutex_unlock(&p->mutex);
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.  On some platforms,
+** there might be race conditions that can cause these routines to
+** deliver incorrect results.  In particular, if pthread_equal() is
+** not an atomic operation, then these routines might delivery
+** incorrect results.  On most platforms, pthread_equal() is a 
+** comparison of two integers and is therefore atomic.  But we are
+** told that HPUX is not such a platform.  If so, then these routines
+** will not always work correctly on HPUX.
+**
+** On those platforms where pthread_equal() is not atomic, SQLite
+** should be compiled without -DSQLITE_DEBUG and with -DNDEBUG to
+** make sure no assert() statements are evaluated and hence these
+** routines are never called.
+*/
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+  return p==0 || (p->nRef!=0 && pthread_equal(p->owner, pthread_self()));
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+  return p==0 || p->nRef==0 || pthread_equal(p->owner, pthread_self())==0;
+}
+#endif
+#endif /* SQLITE_MUTEX_PTHREAD */
+
+/************** End of mutex_unix.c ******************************************/
+/************** Begin file mutex_w32.c ***************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for win32
+**
+** $Id: mutex_w32.c,v 1.6 2008/03/26 18:34:43 danielk1977 Exp $
+*/
+
+/*
+** The code in this file is only used if we are compiling multithreaded
+** on a win32 system.
+*/
+#ifdef SQLITE_MUTEX_W32
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
+  int id;                    /* Mutex type */
+  int nRef;                  /* Number of enterances */
+  DWORD owner;               /* Thread holding this mutex */
+};
+
+/*
+** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
+** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
+**
+** Here is an interesting observation:  Win95, Win98, and WinME lack
+** the LockFileEx() API.  But we can still statically link against that
+** API as long as we don't call it win running Win95/98/ME.  A call to
+** this routine is used to determine if the host is Win95/98/ME or
+** WinNT/2K/XP so that we will know whether or not we can safely call
+** the LockFileEx() API.
+*/
+#if OS_WINCE
+# define mutexIsNT()  (1)
+#else
+  static int mutexIsNT(void){
+    static int osType = 0;
+    if( osType==0 ){
+      OSVERSIONINFO sInfo;
+      sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+      GetVersionEx(&sInfo);
+      osType = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
+    }
+    return osType==2;
+  }
+#endif /* OS_WINCE */
+
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST               0
+** <li>  SQLITE_MUTEX_RECURSIVE          1
+** <li>  SQLITE_MUTEX_STATIC_MASTER      2
+** <li>  SQLITE_MUTEX_STATIC_MEM         3
+** <li>  SQLITE_MUTEX_STATIC_PRNG        4
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Three static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static 
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int iType){
+  sqlite3_mutex *p;
+
+  switch( iType ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        p->id = iType;
+        InitializeCriticalSection(&p->mutex);
+      }
+      break;
+    }
+    default: {
+      static sqlite3_mutex staticMutexes[6];
+      static int isInit = 0;
+      while( !isInit ){
+        static long lock = 0;
+        if( InterlockedIncrement(&lock)==1 ){
+          int i;
+          for(i=0; i<sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++){
+            InitializeCriticalSection(&staticMutexes[i].mutex);
+          }
+          isInit = 1;
+        }else{
+          Sleep(1);
+        }
+      }
+      assert( iType-2 >= 0 );
+      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
+      p = &staticMutexes[iType-2];
+      p->id = iType;
+      break;
+    }
+  }
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  assert( p );
+  assert( p->nRef==0 );
+  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
+  DeleteCriticalSection(&p->mutex);
+  sqlite3_free(p);
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  EnterCriticalSection(&p->mutex);
+  p->owner = GetCurrentThreadId(); 
+  p->nRef++;
+}
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  int rc = SQLITE_BUSY;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) );
+  /*
+  ** The sqlite3_mutex_try() routine is very rarely used, and when it
+  ** is used it is merely an optimization.  So it is OK for it to always
+  ** fail.  
+  **
+  ** The TryEnterCriticalSection() interface is only available on WinNT.
+  ** And some windows compilers complain if you try to use it without
+  ** first doing some #defines that prevent SQLite from building on Win98.
+  ** For that reason, we will omit this optimization for now.  See
+  ** ticket #2685.
+  */
+#if 0
+  if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){
+    p->owner = GetCurrentThreadId();
+    p->nRef++;
+    rc = SQLITE_OK;
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  assert( p->nRef>0 );
+  assert( p->owner==GetCurrentThreadId() );
+  p->nRef--;
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+  LeaveCriticalSection(&p->mutex);
+}
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+  return p==0 || (p->nRef!=0 && p->owner==GetCurrentThreadId());
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+  return p==0 || p->nRef==0 || p->owner!=GetCurrentThreadId();
+}
+#endif /* SQLITE_MUTEX_W32 */
+
+/************** End of mutex_w32.c *******************************************/
+/************** Begin file malloc.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Memory allocation functions used throughout sqlite.
+**
+**
+** $Id: malloc.c,v 1.15 2008/03/26 18:34:43 danielk1977 Exp $
+*/
+
+/*
+** This routine runs when the memory allocator sees that the
+** total memory allocation is about to exceed the soft heap
+** limit.
+*/
+static void softHeapLimitEnforcer(
+  void *NotUsed, 
+  sqlite3_int64 inUse,
+  int allocSize
+){
+  sqlite3_release_memory(allocSize);
+}
+
+/*
+** Set the soft heap-size limit for the current thread. Passing a
+** zero or negative value indicates no limit.
+*/
+SQLITE_API void sqlite3_soft_heap_limit(int n){
+  sqlite3_uint64 iLimit;
+  int overage;
+  if( n<0 ){
+    iLimit = 0;
+  }else{
+    iLimit = n;
+  }
+  if( iLimit>0 ){
+    sqlite3_memory_alarm(softHeapLimitEnforcer, 0, iLimit);
+  }else{
+    sqlite3_memory_alarm(0, 0, 0);
+  }
+  overage = sqlite3_memory_used() - n;
+  if( overage>0 ){
+    sqlite3_release_memory(overage);
+  }
+}
+
+/*
+** Release memory held by SQLite instances created by the current thread.
+*/
+SQLITE_API int sqlite3_release_memory(int n){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  int nRet = sqlite3VdbeReleaseMemory(n);
+  nRet += sqlite3PagerReleaseMemory(n-nRet);
+  return nRet;
+#else
+  return SQLITE_OK;
+#endif
+}
+
+
+/*
+** Allocate and zero memory.
+*/ 
+SQLITE_PRIVATE void *sqlite3MallocZero(unsigned n){
+  void *p = sqlite3_malloc(n);
+  if( p ){
+    memset(p, 0, n);
+  }
+  return p;
+}
+
+/*
+** Allocate and zero memory.  If the allocation fails, make
+** the mallocFailed flag in the connection pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3 *db, unsigned n){
+  void *p = sqlite3DbMallocRaw(db, n);
+  if( p ){
+    memset(p, 0, n);
+  }
+  return p;
+}
+
+/*
+** Allocate and zero memory.  If the allocation fails, make
+** the mallocFailed flag in the connection pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, unsigned n){
+  void *p = 0;
+  if( !db || db->mallocFailed==0 ){
+    p = sqlite3_malloc(n);
+    if( !p && db ){
+      db->mallocFailed = 1;
+    }
+  }
+  return p;
+}
+
+/*
+** Resize the block of memory pointed to by p to n bytes. If the
+** resize fails, set the mallocFailed flag inthe connection object.
+*/
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
+  void *pNew = 0;
+  if( db->mallocFailed==0 ){
+    pNew = sqlite3_realloc(p, n);
+    if( !pNew ){
+      db->mallocFailed = 1;
+    }
+  }
+  return pNew;
+}
+
+/*
+** Attempt to reallocate p.  If the reallocation fails, then free p
+** and set the mallocFailed flag in the database connection.
+*/
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, int n){
+  void *pNew;
+  pNew = sqlite3DbRealloc(db, p, n);
+  if( !pNew ){
+    sqlite3_free(p);
+  }
+  return pNew;
+}
+
+/*
+** Make a copy of a string in memory obtained from sqliteMalloc(). These 
+** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
+** is because when memory debugging is turned on, these two functions are 
+** called via macros that record the current file and line number in the
+** ThreadData structure.
+*/
+SQLITE_PRIVATE char *sqlite3StrDup(const char *z){
+  char *zNew;
+  int n;
+  if( z==0 ) return 0;
+  n = strlen(z)+1;
+  zNew = sqlite3_malloc(n);
+  if( zNew ) memcpy(zNew, z, n);
+  return zNew;
+}
+SQLITE_PRIVATE char *sqlite3StrNDup(const char *z, int n){
+  char *zNew;
+  if( z==0 ) return 0;
+  zNew = sqlite3_malloc(n+1);
+  if( zNew ){
+    memcpy(zNew, z, n);
+    zNew[n] = 0;
+  }
+  return zNew;
+}
+
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3 *db, const char *z){
+  char *zNew = sqlite3StrDup(z);
+  if( z && !zNew ){
+    db->mallocFailed = 1;
+  }
+  return zNew;
+}
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){
+  char *zNew = sqlite3StrNDup(z, n);
+  if( z && !zNew ){
+    db->mallocFailed = 1;
+  }
+  return zNew;
+}
+
+/*
+** Create a string from the 2nd and subsequent arguments (up to the
+** first NULL argument), store the string in memory obtained from
+** sqliteMalloc() and make the pointer indicated by the 1st argument
+** point to that string.  The 1st argument must either be NULL or 
+** point to memory obtained from sqliteMalloc().
+*/
+SQLITE_PRIVATE void sqlite3SetString(char **pz, ...){
+  va_list ap;
+  int nByte;
+  const char *z;
+  char *zResult;
+
+  assert( pz!=0 );
+  nByte = 1;
+  va_start(ap, pz);
+  while( (z = va_arg(ap, const char*))!=0 ){
+    nByte += strlen(z);
+  }
+  va_end(ap);
+  sqlite3_free(*pz);
+  *pz = zResult = sqlite3_malloc(nByte);
+  if( zResult==0 ){
+    return;
+  }
+  *zResult = 0;
+  va_start(ap, pz);
+  while( (z = va_arg(ap, const char*))!=0 ){
+    int n = strlen(z);
+    memcpy(zResult, z, n);
+    zResult += n;
+  }
+  zResult[0] = 0;
+  va_end(ap);
+}
+
+
+/*
+** This function must be called before exiting any API function (i.e. 
+** returning control to the user) that has called sqlite3_malloc or
+** sqlite3_realloc.
+**
+** The returned value is normally a copy of the second argument to this
+** function. However, if a malloc() failure has occured since the previous
+** invocation SQLITE_NOMEM is returned instead. 
+**
+** If the first argument, db, is not NULL and a malloc() error has occured,
+** then the connection error-code (the value returned by sqlite3_errcode())
+** is set to SQLITE_NOMEM.
+*/
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
+  /* If the db handle is not NULL, then we must hold the connection handle
+  ** mutex here. Otherwise the read (and possible write) of db->mallocFailed 
+  ** is unsafe, as is the call to sqlite3Error().
+  */
+  assert( !db || sqlite3_mutex_held(db->mutex) );
+  if( db && db->mallocFailed ){
+    sqlite3Error(db, SQLITE_NOMEM, 0);
+    db->mallocFailed = 0;
+    rc = SQLITE_NOMEM;
+  }
+  return rc & (db ? db->errMask : 0xff);
+}
+
+/************** End of malloc.c **********************************************/
+/************** Begin file printf.c ******************************************/
+/*
+** The "printf" code that follows dates from the 1980's.  It is in
+** the public domain.  The original comments are included here for
+** completeness.  They are very out-of-date but might be useful as
+** an historical reference.  Most of the "enhancements" have been backed
+** out so that the functionality is now the same as standard printf().
+**
+**************************************************************************
+**
+** The following modules is an enhanced replacement for the "printf" subroutines
+** found in the standard C library.  The following enhancements are
+** supported:
+**
+**      +  Additional functions.  The standard set of "printf" functions
+**         includes printf, fprintf, sprintf, vprintf, vfprintf, and
+**         vsprintf.  This module adds the following:
+**
+**           *  snprintf -- Works like sprintf, but has an extra argument
+**                          which is the size of the buffer written to.
+**
+**           *  mprintf --  Similar to sprintf.  Writes output to memory
+**                          obtained from malloc.
+**
+**           *  xprintf --  Calls a function to dispose of output.
+**
+**           *  nprintf --  No output, but returns the number of characters
+**                          that would have been output by printf.
+**
+**           *  A v- version (ex: vsnprintf) of every function is also
+**              supplied.
+**
+**      +  A few extensions to the formatting notation are supported:
+**
+**           *  The "=" flag (similar to "-") causes the output to be
+**              be centered in the appropriately sized field.
+**
+**           *  The %b field outputs an integer in binary notation.
+**
+**           *  The %c field now accepts a precision.  The character output
+**              is repeated by the number of times the precision specifies.
+**
+**           *  The %' field works like %c, but takes as its character the
+**              next character of the format string, instead of the next
+**              argument.  For example,  printf("%.78'-")  prints 78 minus
+**              signs, the same as  printf("%.78c",'-').
+**
+**      +  When compiled using GCC on a SPARC, this version of printf is
+**         faster than the library printf for SUN OS 4.1.
+**
+**      +  All functions are fully reentrant.
+**
+*/
+
+/*
+** Conversion types fall into various categories as defined by the
+** following enumeration.
+*/
+#define etRADIX       1 /* Integer types.  %d, %x, %o, and so forth */
+#define etFLOAT       2 /* Floating point.  %f */
+#define etEXP         3 /* Exponentional notation. %e and %E */
+#define etGENERIC     4 /* Floating or exponential, depending on exponent. %g */
+#define etSIZE        5 /* Return number of characters processed so far. %n */
+#define etSTRING      6 /* Strings. %s */
+#define etDYNSTRING   7 /* Dynamically allocated strings. %z */
+#define etPERCENT     8 /* Percent symbol. %% */
+#define etCHARX       9 /* Characters. %c */
+/* The rest are extensions, not normally found in printf() */
+#define etCHARLIT    10 /* Literal characters.  %' */
+#define etSQLESCAPE  11 /* Strings with '\'' doubled.  %q */
+#define etSQLESCAPE2 12 /* Strings with '\'' doubled and enclosed in '',
+                          NULL pointers replaced by SQL NULL.  %Q */
+#define etTOKEN      13 /* a pointer to a Token structure */
+#define etSRCLIST    14 /* a pointer to a SrcList */
+#define etPOINTER    15 /* The %p conversion */
+#define etSQLESCAPE3 16 /* %w -> Strings with '\"' doubled */
+#define etORDINAL    17 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
+
+
+/*
+** An "etByte" is an 8-bit unsigned value.
+*/
+typedef unsigned char etByte;
+
+/*
+** Each builtin conversion character (ex: the 'd' in "%d") is described
+** by an instance of the following structure
+*/
+typedef struct et_info {   /* Information about each format field */
+  char fmttype;            /* The format field code letter */
+  etByte base;             /* The base for radix conversion */
+  etByte flags;            /* One or more of FLAG_ constants below */
+  etByte type;             /* Conversion paradigm */
+  etByte charset;          /* Offset into aDigits[] of the digits string */
+  etByte prefix;           /* Offset into aPrefix[] of the prefix string */
+} et_info;
+
+/*
+** Allowed values for et_info.flags
+*/
+#define FLAG_SIGNED  1     /* True if the value to convert is signed */
+#define FLAG_INTERN  2     /* True if for internal use only */
+#define FLAG_STRING  4     /* Allow infinity precision */
+
+
+/*
+** The following table is searched linearly, so it is good to put the
+** most frequently used conversion types first.
+*/
+static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
+static const char aPrefix[] = "-x0\000X0";
+static const et_info fmtinfo[] = {
+  {  'd', 10, 1, etRADIX,      0,  0 },
+  {  's',  0, 4, etSTRING,     0,  0 },
+  {  'g',  0, 1, etGENERIC,    30, 0 },
+  {  'z',  0, 4, etDYNSTRING,  0,  0 },
+  {  'q',  0, 4, etSQLESCAPE,  0,  0 },
+  {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
+  {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
+  {  'c',  0, 0, etCHARX,      0,  0 },
+  {  'o',  8, 0, etRADIX,      0,  2 },
+  {  'u', 10, 0, etRADIX,      0,  0 },
+  {  'x', 16, 0, etRADIX,      16, 1 },
+  {  'X', 16, 0, etRADIX,      0,  4 },
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  {  'f',  0, 1, etFLOAT,      0,  0 },
+  {  'e',  0, 1, etEXP,        30, 0 },
+  {  'E',  0, 1, etEXP,        14, 0 },
+  {  'G',  0, 1, etGENERIC,    14, 0 },
+#endif
+  {  'i', 10, 1, etRADIX,      0,  0 },
+  {  'n',  0, 0, etSIZE,       0,  0 },
+  {  '%',  0, 0, etPERCENT,    0,  0 },
+  {  'p', 16, 0, etPOINTER,    0,  1 },
+  {  'T',  0, 2, etTOKEN,      0,  0 },
+  {  'S',  0, 2, etSRCLIST,    0,  0 },
+  {  'r', 10, 3, etORDINAL,    0,  0 },
+};
+#define etNINFO  (sizeof(fmtinfo)/sizeof(fmtinfo[0]))
+
+/*
+** If SQLITE_OMIT_FLOATING_POINT is defined, then none of the floating point
+** conversions will work.
+*/
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** "*val" is a double such that 0.1 <= *val < 10.0
+** Return the ascii code for the leading digit of *val, then
+** multiply "*val" by 10.0 to renormalize.
+**
+** Example:
+**     input:     *val = 3.14159
+**     output:    *val = 1.4159    function return = '3'
+**
+** The counter *cnt is incremented each time.  After counter exceeds
+** 16 (the number of significant digits in a 64-bit float) '0' is
+** always returned.
+*/
+static int et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
+  int digit;
+  LONGDOUBLE_TYPE d;
+  if( (*cnt)++ >= 16 ) return '0';
+  digit = (int)*val;
+  d = digit;
+  digit += '0';
+  *val = (*val - d)*10.0;
+  return digit;
+}
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+
+/*
+** Append N space characters to the given string buffer.
+*/
+static void appendSpace(StrAccum *pAccum, int N){
+  static const char zSpaces[] = "                             ";
+  while( N>=sizeof(zSpaces)-1 ){
+    sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
+    N -= sizeof(zSpaces)-1;
+  }
+  if( N>0 ){
+    sqlite3StrAccumAppend(pAccum, zSpaces, N);
+  }
+}
+
+/*
+** On machines with a small stack size, you can redefine the
+** SQLITE_PRINT_BUF_SIZE to be less than 350.  But beware - for
+** smaller values some %f conversions may go into an infinite loop.
+*/
+#ifndef SQLITE_PRINT_BUF_SIZE
+# define SQLITE_PRINT_BUF_SIZE 350
+#endif
+#define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
+
+/*
+** The root program.  All variations call this core.
+**
+** INPUTS:
+**   func   This is a pointer to a function taking three arguments
+**            1. A pointer to anything.  Same as the "arg" parameter.
+**            2. A pointer to the list of characters to be output
+**               (Note, this list is NOT null terminated.)
+**            3. An integer number of characters to be output.
+**               (Note: This number might be zero.)
+**
+**   arg    This is the pointer to anything which will be passed as the
+**          first argument to "func".  Use it for whatever you like.
+**
+**   fmt    This is the format string, as in the usual print.
+**
+**   ap     This is a pointer to a list of arguments.  Same as in
+**          vfprint.
+**
+** OUTPUTS:
+**          The return value is the total number of characters sent to
+**          the function "func".  Returns -1 on a error.
+**
+** Note that the order in which automatic variables are declared below
+** seems to make a big difference in determining how fast this beast
+** will run.
+*/
+static void vxprintf(
+  StrAccum *pAccum,                  /* Accumulate results here */
+  int useExtended,                   /* Allow extended %-conversions */
+  const char *fmt,                   /* Format string */
+  va_list ap                         /* arguments */
+){
+  int c;                     /* Next character in the format string */
+  char *bufpt;               /* Pointer to the conversion buffer */
+  int precision;             /* Precision of the current field */
+  int length;                /* Length of the field */
+  int idx;                   /* A general purpose loop counter */
+  int width;                 /* Width of the current field */
+  etByte flag_leftjustify;   /* True if "-" flag is present */
+  etByte flag_plussign;      /* True if "+" flag is present */
+  etByte flag_blanksign;     /* True if " " flag is present */
+  etByte flag_alternateform; /* True if "#" flag is present */
+  etByte flag_altform2;      /* True if "!" flag is present */
+  etByte flag_zeropad;       /* True if field width constant starts with zero */
+  etByte flag_long;          /* True if "l" flag is present */
+  etByte flag_longlong;      /* True if the "ll" flag is present */
+  etByte done;               /* Loop termination flag */
+  sqlite_uint64 longvalue;   /* Value for integer types */
+  LONGDOUBLE_TYPE realvalue; /* Value for real types */
+  const et_info *infop;      /* Pointer to the appropriate info structure */
+  char buf[etBUFSIZE];       /* Conversion buffer */
+  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
+  etByte errorflag = 0;      /* True if an error is encountered */
+  etByte xtype;              /* Conversion paradigm */
+  char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  int  exp, e2;              /* exponent of real numbers */
+  double rounder;            /* Used for rounding floating point values */
+  etByte flag_dp;            /* True if decimal point should be shown */
+  etByte flag_rtz;           /* True if trailing zeros should be removed */
+  etByte flag_exp;           /* True to force display of the exponent */
+  int nsd;                   /* Number of significant digits returned */
+#endif
+
+  length = 0;
+  bufpt = 0;
+  for(; (c=(*fmt))!=0; ++fmt){
+    if( c!='%' ){
+      int amt;
+      bufpt = (char *)fmt;
+      amt = 1;
+      while( (c=(*++fmt))!='%' && c!=0 ) amt++;
+      sqlite3StrAccumAppend(pAccum, bufpt, amt);
+      if( c==0 ) break;
+    }
+    if( (c=(*++fmt))==0 ){
+      errorflag = 1;
+      sqlite3StrAccumAppend(pAccum, "%", 1);
+      break;
+    }
+    /* Find out what flags are present */
+    flag_leftjustify = flag_plussign = flag_blanksign = 
+     flag_alternateform = flag_altform2 = flag_zeropad = 0;
+    done = 0;
+    do{
+      switch( c ){
+        case '-':   flag_leftjustify = 1;     break;
+        case '+':   flag_plussign = 1;        break;
+        case ' ':   flag_blanksign = 1;       break;
+        case '#':   flag_alternateform = 1;   break;
+        case '!':   flag_altform2 = 1;        break;
+        case '0':   flag_zeropad = 1;         break;
+        default:    done = 1;                 break;
+      }
+    }while( !done && (c=(*++fmt))!=0 );
+    /* Get the field width */
+    width = 0;
+    if( c=='*' ){
+      width = va_arg(ap,int);
+      if( width<0 ){
+        flag_leftjustify = 1;
+        width = -width;
+      }
+      c = *++fmt;
+    }else{
+      while( c>='0' && c<='9' ){
+        width = width*10 + c - '0';
+        c = *++fmt;
+      }
+    }
+    if( width > etBUFSIZE-10 ){
+      width = etBUFSIZE-10;
+    }
+    /* Get the precision */
+    if( c=='.' ){
+      precision = 0;
+      c = *++fmt;
+      if( c=='*' ){
+        precision = va_arg(ap,int);
+        if( precision<0 ) precision = -precision;
+        c = *++fmt;
+      }else{
+        while( c>='0' && c<='9' ){
+          precision = precision*10 + c - '0';
+          c = *++fmt;
+        }
+      }
+    }else{
+      precision = -1;
+    }
+    /* Get the conversion type modifier */
+    if( c=='l' ){
+      flag_long = 1;
+      c = *++fmt;
+      if( c=='l' ){
+        flag_longlong = 1;
+        c = *++fmt;
+      }else{
+        flag_longlong = 0;
+      }
+    }else{
+      flag_long = flag_longlong = 0;
+    }
+    /* Fetch the info entry for the field */
+    infop = 0;
+    for(idx=0; idx<etNINFO; idx++){
+      if( c==fmtinfo[idx].fmttype ){
+        infop = &fmtinfo[idx];
+        if( useExtended || (infop->flags & FLAG_INTERN)==0 ){
+          xtype = infop->type;
+        }else{
+          return;
+        }
+        break;
+      }
+    }
+    zExtra = 0;
+    if( infop==0 ){
+      return;
+    }
+
+
+    /* Limit the precision to prevent overflowing buf[] during conversion */
+    if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
+      precision = etBUFSIZE-40;
+    }
+
+    /*
+    ** At this point, variables are initialized as follows:
+    **
+    **   flag_alternateform          TRUE if a '#' is present.
+    **   flag_altform2               TRUE if a '!' is present.
+    **   flag_plussign               TRUE if a '+' is present.
+    **   flag_leftjustify            TRUE if a '-' is present or if the
+    **                               field width was negative.
+    **   flag_zeropad                TRUE if the width began with 0.
+    **   flag_long                   TRUE if the letter 'l' (ell) prefixed
+    **                               the conversion character.
+    **   flag_longlong               TRUE if the letter 'll' (ell ell) prefixed
+    **                               the conversion character.
+    **   flag_blanksign              TRUE if a ' ' is present.
+    **   width                       The specified field width.  This is
+    **                               always non-negative.  Zero is the default.
+    **   precision                   The specified precision.  The default
+    **                               is -1.
+    **   xtype                       The class of the conversion.
+    **   infop                       Pointer to the appropriate info struct.
+    */
+    switch( xtype ){
+      case etPOINTER:
+        flag_longlong = sizeof(char*)==sizeof(i64);
+        flag_long = sizeof(char*)==sizeof(long int);
+        /* Fall through into the next case */
+      case etORDINAL:
+      case etRADIX:
+        if( infop->flags & FLAG_SIGNED ){
+          i64 v;
+          if( flag_longlong )   v = va_arg(ap,i64);
+          else if( flag_long )  v = va_arg(ap,long int);
+          else                  v = va_arg(ap,int);
+          if( v<0 ){
+            longvalue = -v;
+            prefix = '-';
+          }else{
+            longvalue = v;
+            if( flag_plussign )        prefix = '+';
+            else if( flag_blanksign )  prefix = ' ';
+            else                       prefix = 0;
+          }
+        }else{
+          if( flag_longlong )   longvalue = va_arg(ap,u64);
+          else if( flag_long )  longvalue = va_arg(ap,unsigned long int);
+          else                  longvalue = va_arg(ap,unsigned int);
+          prefix = 0;
+        }
+        if( longvalue==0 ) flag_alternateform = 0;
+        if( flag_zeropad && precision<width-(prefix!=0) ){
+          precision = width-(prefix!=0);
+        }
+        bufpt = &buf[etBUFSIZE-1];
+        if( xtype==etORDINAL ){
+          static const char zOrd[] = "thstndrd";
+          int x = longvalue % 10;
+          if( x>=4 || (longvalue/10)%10==1 ){
+            x = 0;
+          }
+          buf[etBUFSIZE-3] = zOrd[x*2];
+          buf[etBUFSIZE-2] = zOrd[x*2+1];
+          bufpt -= 2;
+        }
+        {
+          register const char *cset;      /* Use registers for speed */
+          register int base;
+          cset = &aDigits[infop->charset];
+          base = infop->base;
+          do{                                           /* Convert to ascii */
+            *(--bufpt) = cset[longvalue%base];
+            longvalue = longvalue/base;
+          }while( longvalue>0 );
+        }
+        length = &buf[etBUFSIZE-1]-bufpt;
+        for(idx=precision-length; idx>0; idx--){
+          *(--bufpt) = '0';                             /* Zero pad */
+        }
+        if( prefix ) *(--bufpt) = prefix;               /* Add sign */
+        if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
+          const char *pre;
+          char x;
+          pre = &aPrefix[infop->prefix];
+          if( *bufpt!=pre[0] ){
+            for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
+          }
+        }
+        length = &buf[etBUFSIZE-1]-bufpt;
+        break;
+      case etFLOAT:
+      case etEXP:
+      case etGENERIC:
+        realvalue = va_arg(ap,double);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        if( precision<0 ) precision = 6;         /* Set default precision */
+        if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
+        if( realvalue<0.0 ){
+          realvalue = -realvalue;
+          prefix = '-';
+        }else{
+          if( flag_plussign )          prefix = '+';
+          else if( flag_blanksign )    prefix = ' ';
+          else                         prefix = 0;
+        }
+        if( xtype==etGENERIC && precision>0 ) precision--;
+#if 0
+        /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
+        for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
+#else
+        /* It makes more sense to use 0.5 */
+        for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1){}
+#endif
+        if( xtype==etFLOAT ) realvalue += rounder;
+        /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
+        exp = 0;
+        if( sqlite3IsNaN(realvalue) ){
+          bufpt = "NaN";
+          length = 3;
+          break;
+        }
+        if( realvalue>0.0 ){
+          while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
+          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
+          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
+          while( realvalue<1e-8 && exp>=-350 ){ realvalue *= 1e8; exp-=8; }
+          while( realvalue<1.0 && exp>=-350 ){ realvalue *= 10.0; exp--; }
+          if( exp>350 || exp<-350 ){
+            if( prefix=='-' ){
+              bufpt = "-Inf";
+            }else if( prefix=='+' ){
+              bufpt = "+Inf";
+            }else{
+              bufpt = "Inf";
+            }
+            length = strlen(bufpt);
+            break;
+          }
+        }
+        bufpt = buf;
+        /*
+        ** If the field type is etGENERIC, then convert to either etEXP
+        ** or etFLOAT, as appropriate.
+        */
+        flag_exp = xtype==etEXP;
+        if( xtype!=etFLOAT ){
+          realvalue += rounder;
+          if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
+        }
+        if( xtype==etGENERIC ){
+          flag_rtz = !flag_alternateform;
+          if( exp<-4 || exp>precision ){
+            xtype = etEXP;
+          }else{
+            precision = precision - exp;
+            xtype = etFLOAT;
+          }
+        }else{
+          flag_rtz = 0;
+        }
+        if( xtype==etEXP ){
+          e2 = 0;
+        }else{
+          e2 = exp;
+        }
+        nsd = 0;
+        flag_dp = (precision>0) | flag_alternateform | flag_altform2;
+        /* The sign in front of the number */
+        if( prefix ){
+          *(bufpt++) = prefix;
+        }
+        /* Digits prior to the decimal point */
+        if( e2<0 ){
+          *(bufpt++) = '0';
+        }else{
+          for(; e2>=0; e2--){
+            *(bufpt++) = et_getdigit(&realvalue,&nsd);
+          }
+        }
+        /* The decimal point */
+        if( flag_dp ){
+          *(bufpt++) = '.';
+        }
+        /* "0" digits after the decimal point but before the first
+        ** significant digit of the number */
+        for(e2++; e2<0 && precision>0; precision--, e2++){
+          *(bufpt++) = '0';
+        }
+        /* Significant digits after the decimal point */
+        while( (precision--)>0 ){
+          *(bufpt++) = et_getdigit(&realvalue,&nsd);
+        }
+        /* Remove trailing zeros and the "." if no digits follow the "." */
+        if( flag_rtz && flag_dp ){
+          while( bufpt[-1]=='0' ) *(--bufpt) = 0;
+          assert( bufpt>buf );
+          if( bufpt[-1]=='.' ){
+            if( flag_altform2 ){
+              *(bufpt++) = '0';
+            }else{
+              *(--bufpt) = 0;
+            }
+          }
+        }
+        /* Add the "eNNN" suffix */
+        if( flag_exp || (xtype==etEXP && exp) ){
+          *(bufpt++) = aDigits[infop->charset];
+          if( exp<0 ){
+            *(bufpt++) = '-'; exp = -exp;
+          }else{
+            *(bufpt++) = '+';
+          }
+          if( exp>=100 ){
+            *(bufpt++) = (exp/100)+'0';                /* 100's digit */
+            exp %= 100;
+          }
+          *(bufpt++) = exp/10+'0';                     /* 10's digit */
+          *(bufpt++) = exp%10+'0';                     /* 1's digit */
+        }
+        *bufpt = 0;
+
+        /* The converted number is in buf[] and zero terminated. Output it.
+        ** Note that the number is in the usual order, not reversed as with
+        ** integer conversions. */
+        length = bufpt-buf;
+        bufpt = buf;
+
+        /* Special case:  Add leading zeros if the flag_zeropad flag is
+        ** set and we are not left justified */
+        if( flag_zeropad && !flag_leftjustify && length < width){
+          int i;
+          int nPad = width - length;
+          for(i=width; i>=nPad; i--){
+            bufpt[i] = bufpt[i-nPad];
+          }
+          i = prefix!=0;
+          while( nPad-- ) bufpt[i++] = '0';
+          length = width;
+        }
+#endif
+        break;
+      case etSIZE:
+        *(va_arg(ap,int*)) = pAccum->nChar;
+        length = width = 0;
+        break;
+      case etPERCENT:
+        buf[0] = '%';
+        bufpt = buf;
+        length = 1;
+        break;
+      case etCHARLIT:
+      case etCHARX:
+        c = buf[0] = (xtype==etCHARX ? va_arg(ap,int) : *++fmt);
+        if( precision>=0 ){
+          for(idx=1; idx<precision; idx++) buf[idx] = c;
+          length = precision;
+        }else{
+          length =1;
+        }
+        bufpt = buf;
+        break;
+      case etSTRING:
+      case etDYNSTRING:
+        bufpt = va_arg(ap,char*);
+        if( bufpt==0 ){
+          bufpt = "";
+        }else if( xtype==etDYNSTRING ){
+          zExtra = bufpt;
+        }
+        if( precision>=0 ){
+          for(length=0; length<precision && bufpt[length]; length++){}
+        }else{
+          length = strlen(bufpt);
+        }
+        break;
+      case etSQLESCAPE:
+      case etSQLESCAPE2:
+      case etSQLESCAPE3: {
+        int i, j, n, ch, isnull;
+        int needQuote;
+        char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
+        char *escarg = va_arg(ap,char*);
+        isnull = escarg==0;
+        if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
+        for(i=n=0; (ch=escarg[i])!=0; i++){
+          if( ch==q )  n++;
+        }
+        needQuote = !isnull && xtype==etSQLESCAPE2;
+        n += i + 1 + needQuote*2;
+        if( n>etBUFSIZE ){
+          bufpt = zExtra = sqlite3_malloc( n );
+          if( bufpt==0 ) return;
+        }else{
+          bufpt = buf;
+        }
+        j = 0;
+        if( needQuote ) bufpt[j++] = q;
+        for(i=0; (ch=escarg[i])!=0; i++){
+          bufpt[j++] = ch;
+          if( ch==q ) bufpt[j++] = ch;
+        }
+        if( needQuote ) bufpt[j++] = q;
+        bufpt[j] = 0;
+        length = j;
+        /* The precision is ignored on %q and %Q */
+        /* if( precision>=0 && precision<length ) length = precision; */
+        break;
+      }
+      case etTOKEN: {
+        Token *pToken = va_arg(ap, Token*);
+        if( pToken && pToken->z ){
+          sqlite3StrAccumAppend(pAccum, (const char*)pToken->z, pToken->n);
+        }
+        length = width = 0;
+        break;
+      }
+      case etSRCLIST: {
+        SrcList *pSrc = va_arg(ap, SrcList*);
+        int k = va_arg(ap, int);
+        struct SrcList_item *pItem = &pSrc->a[k];
+        assert( k>=0 && k<pSrc->nSrc );
+        if( pItem->zDatabase && pItem->zDatabase[0] ){
+          sqlite3StrAccumAppend(pAccum, pItem->zDatabase, -1);
+          sqlite3StrAccumAppend(pAccum, ".", 1);
+        }
+        sqlite3StrAccumAppend(pAccum, pItem->zName, -1);
+        length = width = 0;
+        break;
+      }
+    }/* End switch over the format type */
+    /*
+    ** The text of the conversion is pointed to by "bufpt" and is
+    ** "length" characters long.  The field width is "width".  Do
+    ** the output.
+    */
+    if( !flag_leftjustify ){
+      register int nspace;
+      nspace = width-length;
+      if( nspace>0 ){
+        appendSpace(pAccum, nspace);
+      }
+    }
+    if( length>0 ){
+      sqlite3StrAccumAppend(pAccum, bufpt, length);
+    }
+    if( flag_leftjustify ){
+      register int nspace;
+      nspace = width-length;
+      if( nspace>0 ){
+        appendSpace(pAccum, nspace);
+      }
+    }
+    if( zExtra ){
+      sqlite3_free(zExtra);
+    }
+  }/* End for loop over the format string */
+} /* End of function */
+
+/*
+** Append N bytes of text from z to the StrAccum object.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
+  if( p->tooBig | p->mallocFailed ){
+    return;
+  }
+  if( N<0 ){
+    N = strlen(z);
+  }
+  if( N==0 ){
+    return;
+  }
+  if( p->nChar+N >= p->nAlloc ){
+    char *zNew;
+    if( !p->useMalloc ){
+      p->tooBig = 1;
+      N = p->nAlloc - p->nChar - 1;
+      if( N<=0 ){
+        return;
+      }
+    }else{
+      i64 szNew = p->nAlloc;
+      szNew += N + 1;
+      if( szNew > p->mxAlloc ){
+        p->nAlloc = p->mxAlloc;
+        if( ((i64)p->nChar)+((i64)N) >= p->nAlloc ){
+          sqlite3StrAccumReset(p);
+          p->tooBig = 1;
+          return;
+        }
+      }else{
+        p->nAlloc = szNew;
+      }
+      zNew = sqlite3_malloc( p->nAlloc );
+      if( zNew ){
+        memcpy(zNew, p->zText, p->nChar);
+        sqlite3StrAccumReset(p);
+        p->zText = zNew;
+      }else{
+        p->mallocFailed = 1;
+        sqlite3StrAccumReset(p);
+        return;
+      }
+    }
+  }
+  memcpy(&p->zText[p->nChar], z, N);
+  p->nChar += N;
+}
+
+/*
+** Finish off a string by making sure it is zero-terminated.
+** Return a pointer to the resulting string.  Return a NULL
+** pointer if any kind of error was encountered.
+*/
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum *p){
+  if( p->zText ){
+    p->zText[p->nChar] = 0;
+    if( p->useMalloc && p->zText==p->zBase ){
+      p->zText = sqlite3_malloc( p->nChar+1 );
+      if( p->zText ){
+        memcpy(p->zText, p->zBase, p->nChar+1);
+      }else{
+        p->mallocFailed = 1;
+      }
+    }
+  }
+  return p->zText;
+}
+
+/*
+** Reset an StrAccum string.  Reclaim all malloced memory.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum *p){
+  if( p->zText!=p->zBase ){
+    sqlite3_free(p->zText);
+    p->zText = 0;
+  }
+}
+
+/*
+** Initialize a string accumulator
+*/
+static void sqlite3StrAccumInit(StrAccum *p, char *zBase, int n, int mx){
+  p->zText = p->zBase = zBase;
+  p->nChar = 0;
+  p->nAlloc = n;
+  p->mxAlloc = mx;
+  p->useMalloc = 1;
+  p->tooBig = 0;
+  p->mallocFailed = 0;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+  sqlite3StrAccumInit(&acc, zBase, sizeof(zBase),
+                      db ? db->aLimit[SQLITE_LIMIT_LENGTH] : SQLITE_MAX_LENGTH);
+  vxprintf(&acc, 1, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  if( acc.mallocFailed && db ){
+    db->mallocFailed = 1;
+  }
+  return z;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
+  va_list ap;
+  char *z;
+  va_start(ap, zFormat);
+  z = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_vmprintf(const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+  sqlite3StrAccumInit(&acc, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
+  vxprintf(&acc, 0, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc()().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_mprintf(const char *zFormat, ...){
+  va_list ap;
+  char *z;
+  va_start(ap, zFormat);
+  z = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** sqlite3_snprintf() works like snprintf() except that it ignores the
+** current locale settings.  This is important for SQLite because we
+** are not able to use a "," as the decimal point in place of "." as
+** specified by some locales.
+*/
+SQLITE_API char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
+  char *z;
+  va_list ap;
+  StrAccum acc;
+
+  if( n<=0 ){
+    return zBuf;
+  }
+  sqlite3StrAccumInit(&acc, zBuf, n, 0);
+  acc.useMalloc = 0;
+  va_start(ap,zFormat);
+  vxprintf(&acc, 0, zFormat, ap);
+  va_end(ap);
+  z = sqlite3StrAccumFinish(&acc);
+  return z;
+}
+
+#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) || defined(SQLITE_MEMDEBUG)
+/*
+** A version of printf() that understands %lld.  Used for debugging.
+** The printf() built into some versions of windows does not understand %lld
+** and segfaults if you give it a long long int.
+*/
+SQLITE_PRIVATE void sqlite3DebugPrintf(const char *zFormat, ...){
+  va_list ap;
+  StrAccum acc;
+  char zBuf[500];
+  sqlite3StrAccumInit(&acc, zBuf, sizeof(zBuf), 0);
+  acc.useMalloc = 0;
+  va_start(ap,zFormat);
+  vxprintf(&acc, 0, zFormat, ap);
+  va_end(ap);
+  sqlite3StrAccumFinish(&acc);
+  fprintf(stdout,"%s", zBuf);
+  fflush(stdout);
+}
+#endif
+
+/************** End of printf.c **********************************************/
+/************** Begin file random.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement a pseudo-random number
+** generator (PRNG) for SQLite.
+**
+** Random numbers are used by some of the database backends in order
+** to generate random integer keys for tables or random filenames.
+**
+** $Id: random.c,v 1.23 2008/03/21 16:45:47 drh Exp $
+*/
+
+
+/* All threads share a single random number generator.
+** This structure is the current state of the generator.
+*/
+static struct sqlite3PrngType {
+  unsigned char isInit;          /* True if initialized */
+  unsigned char i, j;            /* State variables */
+  unsigned char s[256];          /* State variables */
+} sqlite3Prng;
+
+/*
+** Get a single 8-bit random value from the RC4 PRNG.  The Mutex
+** must be held while executing this routine.
+**
+** Why not just use a library random generator like lrand48() for this?
+** Because the OP_NewRowid opcode in the VDBE depends on having a very
+** good source of random numbers.  The lrand48() library function may
+** well be good enough.  But maybe not.  Or maybe lrand48() has some
+** subtle problems on some systems that could cause problems.  It is hard
+** to know.  To minimize the risk of problems due to bad lrand48()
+** implementations, SQLite uses this random number generator based
+** on RC4, which we know works very well.
+**
+** (Later):  Actually, OP_NewRowid does not depend on a good source of
+** randomness any more.  But we will leave this code in all the same.
+*/
+static int randomByte(void){
+  unsigned char t;
+
+
+  /* Initialize the state of the random number generator once,
+  ** the first time this routine is called.  The seed value does
+  ** not need to contain a lot of randomness since we are not
+  ** trying to do secure encryption or anything like that...
+  **
+  ** Nothing in this file or anywhere else in SQLite does any kind of
+  ** encryption.  The RC4 algorithm is being used as a PRNG (pseudo-random
+  ** number generator) not as an encryption device.
+  */
+  if( !sqlite3Prng.isInit ){
+    int i;
+    char k[256];
+    sqlite3Prng.j = 0;
+    sqlite3Prng.i = 0;
+    sqlite3OsRandomness(sqlite3_vfs_find(0), 256, k);
+    for(i=0; i<256; i++){
+      sqlite3Prng.s[i] = i;
+    }
+    for(i=0; i<256; i++){
+      sqlite3Prng.j += sqlite3Prng.s[i] + k[i];
+      t = sqlite3Prng.s[sqlite3Prng.j];
+      sqlite3Prng.s[sqlite3Prng.j] = sqlite3Prng.s[i];
+      sqlite3Prng.s[i] = t;
+    }
+    sqlite3Prng.isInit = 1;
+  }
+
+  /* Generate and return single random byte
+  */
+  sqlite3Prng.i++;
+  t = sqlite3Prng.s[sqlite3Prng.i];
+  sqlite3Prng.j += t;
+  sqlite3Prng.s[sqlite3Prng.i] = sqlite3Prng.s[sqlite3Prng.j];
+  sqlite3Prng.s[sqlite3Prng.j] = t;
+  t += sqlite3Prng.s[sqlite3Prng.i];
+  return sqlite3Prng.s[t];
+}
+
+/*
+** Return N random bytes.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *pBuf){
+  unsigned char *zBuf = pBuf;
+  static sqlite3_mutex *mutex = 0;
+  if( mutex==0 ){
+    mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG);
+  }
+  sqlite3_mutex_enter(mutex);
+  while( N-- ){
+    *(zBuf++) = randomByte();
+  }
+  sqlite3_mutex_leave(mutex);
+}
+
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+/*
+** For testing purposes, we sometimes want to preserve the state of
+** PRNG and restore the PRNG to its saved state at a later time.
+** The sqlite3_test_control() interface calls these routines to
+** control the PRNG.
+*/
+static struct sqlite3PrngType sqlite3SavedPrng;
+SQLITE_PRIVATE void sqlite3PrngSaveState(void){
+  memcpy(&sqlite3SavedPrng, &sqlite3Prng, sizeof(sqlite3Prng));
+}
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void){
+  memcpy(&sqlite3Prng, &sqlite3SavedPrng, sizeof(sqlite3Prng));
+}
+SQLITE_PRIVATE void sqlite3PrngResetState(void){
+  sqlite3Prng.isInit = 0;
+}
+#endif /* SQLITE_OMIT_BUILTIN_TEST */
+
+/************** End of random.c **********************************************/
+/************** Begin file utf.c *********************************************/
+/*
+** 2004 April 13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used to translate between UTF-8, 
+** UTF-16, UTF-16BE, and UTF-16LE.
+**
+** $Id: utf.c,v 1.61 2008/03/28 15:44:10 danielk1977 Exp $
+**
+** Notes on UTF-8:
+**
+**   Byte-0    Byte-1    Byte-2    Byte-3    Value
+**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
+**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
+**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
+**  11110uuu  10uuzzzz  10yyyyyy  10xxxxxx   000uuuuu zzzzyyyy yyxxxxxx
+**
+**
+** Notes on UTF-16:  (with wwww+1==uuuuu)
+**
+**      Word-0               Word-1          Value
+**  110110ww wwzzzzyy   110111yy yyxxxxxx    000uuuuu zzzzyyyy yyxxxxxx
+**  zzzzyyyy yyxxxxxx                        00000000 zzzzyyyy yyxxxxxx
+**
+**
+** BOM or Byte Order Mark:
+**     0xff 0xfe   little-endian utf-16 follows
+**     0xfe 0xff   big-endian utf-16 follows
+**
+*/
+/************** Include vdbeInt.h in the middle of utf.c *********************/
+/************** Begin file vdbeInt.h *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for information that is private to the
+** VDBE.  This information used to all be at the top of the single
+** source code file "vdbe.c".  When that file became too big (over
+** 6000 lines long) it was split up into several smaller files and
+** this header information was factored out.
+*/
+#ifndef _VDBEINT_H_
+#define _VDBEINT_H_
+
+/*
+** intToKey() and keyToInt() used to transform the rowid.  But with
+** the latest versions of the design they are no-ops.
+*/
+#define keyToInt(X)   (X)
+#define intToKey(X)   (X)
+
+
+/*
+** SQL is translated into a sequence of instructions to be
+** executed by a virtual machine.  Each instruction is an instance
+** of the following structure.
+*/
+typedef struct VdbeOp Op;
+
+/*
+** Boolean values
+*/
+typedef unsigned char Bool;
+
+/*
+** A cursor is a pointer into a single BTree within a database file.
+** The cursor can seek to a BTree entry with a particular key, or
+** loop over all entries of the Btree.  You can also insert new BTree
+** entries or retrieve the key or data from the entry that the cursor
+** is currently pointing to.
+** 
+** Every cursor that the virtual machine has open is represented by an
+** instance of the following structure.
+**
+** If the Cursor.isTriggerRow flag is set it means that this cursor is
+** really a single row that represents the NEW or OLD pseudo-table of
+** a row trigger.  The data for the row is stored in Cursor.pData and
+** the rowid is in Cursor.iKey.
+*/
+struct Cursor {
+  BtCursor *pCursor;    /* The cursor structure of the backend */
+  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
+  i64 lastRowid;        /* Last rowid from a Next or NextIdx operation */
+  i64 nextRowid;        /* Next rowid returned by OP_NewRowid */
+  Bool zeroed;          /* True if zeroed out and ready for reuse */
+  Bool rowidIsValid;    /* True if lastRowid is valid */
+  Bool atFirst;         /* True if pointing to first entry */
+  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
+  Bool nullRow;         /* True if pointing to a row with no data */
+  Bool nextRowidValid;  /* True if the nextRowid field is valid */
+  Bool pseudoTable;     /* This is a NEW or OLD pseudo-tables of a trigger */
+  Bool ephemPseudoTable;
+  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */
+  Bool isTable;         /* True if a table requiring integer keys */
+  Bool isIndex;         /* True if an index containing keys only - no data */
+  u8 bogusIncrKey;      /* Something for pIncrKey to point to if pKeyInfo==0 */
+  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
+  Btree *pBt;           /* Separate file holding temporary table */
+  int nData;            /* Number of bytes in pData */
+  char *pData;          /* Data for a NEW or OLD pseudo-table */
+  i64 iKey;             /* Key for the NEW or OLD pseudo-table row */
+  u8 *pIncrKey;         /* Pointer to pKeyInfo->incrKey */
+  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
+  int nField;           /* Number of fields in the header */
+  i64 seqCount;         /* Sequence counter */
+  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
+  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */
+
+  /* Cached information about the header for the data record that the
+  ** cursor is currently pointing to.  Only valid if cacheValid is true.
+  ** aRow might point to (ephemeral) data for the current row, or it might
+  ** be NULL.
+  */
+  int cacheStatus;      /* Cache is valid if this matches Vdbe.cacheCtr */
+  int payloadSize;      /* Total number of bytes in the record */
+  u32 *aType;           /* Type values for all entries in the record */
+  u32 *aOffset;         /* Cached offsets to the start of each columns data */
+  u8 *aRow;             /* Data for the current row, if all on one page */
+};
+typedef struct Cursor Cursor;
+
+/*
+** A value for Cursor.cacheValid that means the cache is always invalid.
+*/
+#define CACHE_STALE 0
+
+/*
+** Internally, the vdbe manipulates nearly all SQL values as Mem
+** structures. Each Mem struct may cache multiple representations (string,
+** integer etc.) of the same value.  A value (and therefore Mem structure)
+** has the following properties:
+**
+** Each value has a manifest type. The manifest type of the value stored
+** in a Mem struct is returned by the MemType(Mem*) macro. The type is
+** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
+** SQLITE_BLOB.
+*/
+struct Mem {
+  union {
+    i64 i;              /* Integer value. Or FuncDef* when flags==MEM_Agg */
+    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
+  } u;
+  double r;           /* Real value */
+  sqlite3 *db;        /* The associated database connection */
+  char *z;            /* String or BLOB value */
+  int n;              /* Number of characters in string value, excluding '\0' */
+  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
+  u8  type;           /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
+  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
+  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */
+  char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
+};
+
+/* One or more of the following flags are set to indicate the validOK
+** representations of the value stored in the Mem struct.
+**
+** If the MEM_Null flag is set, then the value is an SQL NULL value.
+** No other flags may be set in this case.
+**
+** If the MEM_Str flag is set then Mem.z points at a string representation.
+** Usually this is encoded in the same unicode encoding as the main
+** database (see below for exceptions). If the MEM_Term flag is also
+** set, then the string is nul terminated. The MEM_Int and MEM_Real 
+** flags may coexist with the MEM_Str flag.
+**
+** Multiple of these values can appear in Mem.flags.  But only one
+** at a time can appear in Mem.type.
+*/
+#define MEM_Null      0x0001   /* Value is NULL */
+#define MEM_Str       0x0002   /* Value is a string */
+#define MEM_Int       0x0004   /* Value is an integer */
+#define MEM_Real      0x0008   /* Value is a real number */
+#define MEM_Blob      0x0010   /* Value is a BLOB */
+
+#define MemSetTypeFlag(p, f) \
+  ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f)
+
+/* Whenever Mem contains a valid string or blob representation, one of
+** the following flags must be set to determine the memory management
+** policy for Mem.z.  The MEM_Term flag tells us whether or not the
+** string is \000 or \u0000 terminated
+*/
+#define MEM_Term      0x0020   /* String rep is nul terminated */
+#define MEM_Dyn       0x0040   /* Need to call sqliteFree() on Mem.z */
+#define MEM_Static    0x0080   /* Mem.z points to a static string */
+#define MEM_Ephem     0x0100   /* Mem.z points to an ephemeral string */
+#define MEM_Agg       0x0400   /* Mem.z points to an agg function context */
+#define MEM_Zero      0x0800   /* Mem.i contains count of 0s appended to blob */
+
+#ifdef SQLITE_OMIT_INCRBLOB
+  #undef MEM_Zero
+  #define MEM_Zero 0x0000
+#endif
+
+
+/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
+** additional information about auxiliary information bound to arguments
+** of the function.  This is used to implement the sqlite3_get_auxdata()
+** and sqlite3_set_auxdata() APIs.  The "auxdata" is some auxiliary data
+** that can be associated with a constant argument to a function.  This
+** allows functions such as "regexp" to compile their constant regular
+** expression argument once and reused the compiled code for multiple
+** invocations.
+*/
+struct VdbeFunc {
+  FuncDef *pFunc;               /* The definition of the function */
+  int nAux;                     /* Number of entries allocated for apAux[] */
+  struct AuxData {
+    void *pAux;                   /* Aux data for the i-th argument */
+    void (*xDelete)(void *);      /* Destructor for the aux data */
+  } apAux[1];                   /* One slot for each function argument */
+};
+
+/*
+** The "context" argument for a installable function.  A pointer to an
+** instance of this structure is the first argument to the routines used
+** implement the SQL functions.
+**
+** There is a typedef for this structure in sqlite.h.  So all routines,
+** even the public interface to SQLite, can use a pointer to this structure.
+** But this file is the only place where the internal details of this
+** structure are known.
+**
+** This structure is defined inside of vdbeInt.h because it uses substructures
+** (Mem) which are only defined there.
+*/
+struct sqlite3_context {
+  FuncDef *pFunc;       /* Pointer to function information.  MUST BE FIRST */
+  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
+  Mem s;                /* The return value is stored here */
+  Mem *pMem;            /* Memory cell used to store aggregate context */
+  int isError;          /* Error code returned by the function. */
+  CollSeq *pColl;       /* Collating sequence */
+};
+
+/*
+** A Set structure is used for quick testing to see if a value
+** is part of a small set.  Sets are used to implement code like
+** this:
+**            x.y IN ('hi','hoo','hum')
+*/
+typedef struct Set Set;
+struct Set {
+  Hash hash;             /* A set is just a hash table */
+  HashElem *prev;        /* Previously accessed hash elemen */
+};
+
+/*
+** A FifoPage structure holds a single page of valves.  Pages are arranged
+** in a list.
+*/
+typedef struct FifoPage FifoPage;
+struct FifoPage {
+  int nSlot;         /* Number of entries aSlot[] */
+  int iWrite;        /* Push the next value into this entry in aSlot[] */
+  int iRead;         /* Read the next value from this entry in aSlot[] */
+  FifoPage *pNext;   /* Next page in the fifo */
+  i64 aSlot[1];      /* One or more slots for rowid values */
+};
+
+/*
+** The Fifo structure is typedef-ed in vdbeInt.h.  But the implementation
+** of that structure is private to this file.
+**
+** The Fifo structure describes the entire fifo.  
+*/
+typedef struct Fifo Fifo;
+struct Fifo {
+  int nEntry;         /* Total number of entries */
+  FifoPage *pFirst;   /* First page on the list */
+  FifoPage *pLast;    /* Last page on the list */
+};
+
+/*
+** A Context stores the last insert rowid, the last statement change count,
+** and the current statement change count (i.e. changes since last statement).
+** The current keylist is also stored in the context.
+** Elements of Context structure type make up the ContextStack, which is
+** updated by the ContextPush and ContextPop opcodes (used by triggers).
+** The context is pushed before executing a trigger a popped when the
+** trigger finishes.
+*/
+typedef struct Context Context;
+struct Context {
+  i64 lastRowid;    /* Last insert rowid (sqlite3.lastRowid) */
+  int nChange;      /* Statement changes (Vdbe.nChanges)     */
+  Fifo sFifo;       /* Records that will participate in a DELETE or UPDATE */
+};
+
+/*
+** An instance of the virtual machine.  This structure contains the complete
+** state of the virtual machine.
+**
+** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
+** is really a pointer to an instance of this structure.
+**
+** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
+** any virtual table method invocations made by the vdbe program. It is
+** set to 2 for xDestroy method calls and 1 for all other methods. This
+** variable is used for two purposes: to allow xDestroy methods to execute
+** "DROP TABLE" statements and to prevent some nasty side effects of
+** malloc failure when SQLite is invoked recursively by a virtual table 
+** method function.
+*/
+struct Vdbe {
+  sqlite3 *db;        /* The whole database */
+  Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
+  int nOp;            /* Number of instructions in the program */
+  int nOpAlloc;       /* Number of slots allocated for aOp[] */
+  Op *aOp;            /* Space to hold the virtual machine's program */
+  int nLabel;         /* Number of labels used */
+  int nLabelAlloc;    /* Number of slots allocated in aLabel[] */
+  int *aLabel;        /* Space to hold the labels */
+  Mem **apArg;        /* Arguments to currently executing user function */
+  Mem *aColName;      /* Column names to return */
+  int nCursor;        /* Number of slots in apCsr[] */
+  Cursor **apCsr;     /* One element of this array for each open cursor */
+  int nVar;           /* Number of entries in aVar[] */
+  Mem *aVar;          /* Values for the OP_Variable opcode. */
+  char **azVar;       /* Name of variables */
+  int okVar;          /* True if azVar[] has been initialized */
+  int magic;              /* Magic number for sanity checking */
+  int nMem;               /* Number of memory locations currently allocated */
+  Mem *aMem;              /* The memory locations */
+  int nCallback;          /* Number of callbacks invoked so far */
+  int cacheCtr;           /* Cursor row cache generation counter */
+  Fifo sFifo;             /* A list of ROWIDs */
+  int contextStackTop;    /* Index of top element in the context stack */
+  int contextStackDepth;  /* The size of the "context" stack */
+  Context *contextStack;  /* Stack used by opcodes ContextPush & ContextPop*/
+  int pc;                 /* The program counter */
+  int rc;                 /* Value to return */
+  unsigned uniqueCnt;     /* Used by OP_MakeRecord when P2!=0 */
+  int errorAction;        /* Recovery action to do in case of an error */
+  int inTempTrans;        /* True if temp database is transactioned */
+  int returnStack[25];    /* Return address stack for OP_Gosub & OP_Return */
+  int returnDepth;        /* Next unused element in returnStack[] */
+  int nResColumn;         /* Number of columns in one row of the result set */
+  char **azResColumn;     /* Values for one row of result */ 
+  char *zErrMsg;          /* Error message written here */
+  Mem *pResultSet;        /* Pointer to an array of results */
+  u8 explain;             /* True if EXPLAIN present on SQL command */
+  u8 changeCntOn;         /* True to update the change-counter */
+  u8 aborted;             /* True if ROLLBACK in another VM causes an abort */
+  u8 expired;             /* True if the VM needs to be recompiled */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
+  u8 inVtabMethod;        /* See comments above */
+  int nChange;            /* Number of db changes made since last reset */
+  i64 startTime;          /* Time when query started - used for profiling */
+  int btreeMask;          /* Bitmask of db->aDb[] entries referenced */
+  BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
+  int nSql;             /* Number of bytes in zSql */
+  char *zSql;           /* Text of the SQL statement that generated this */
+#ifdef SQLITE_DEBUG
+  FILE *trace;        /* Write an execution trace here, if not NULL */
+#endif
+  int openedStatement;  /* True if this VM has opened a statement journal */
+#ifdef SQLITE_SSE
+  int fetchId;          /* Statement number used by sqlite3_fetch_statement */
+  int lru;              /* Counter used for LRU cache replacement */
+#endif
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  Vdbe *pLruPrev;
+  Vdbe *pLruNext;
+#endif
+};
+
+/*
+** An instance of the following structure holds information about a
+** single index record that has already been parsed out into individual
+** values.
+**
+** A record is an object that contains one or more fields of data.
+** Records are used to store the content of a table row and to store
+** the key of an index.  A blob encoding of a record is created by
+** the OP_MakeRecord opcode of the VDBE and is disassemblied by the
+** OP_Column opcode.
+**
+** This structure holds a record that has already been disassembled
+** into its constitutent fields.
+*/
+struct UnpackedRecord {
+  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
+  u16 nField;         /* Number of entries in apMem[] */
+  u8 needFree;        /* True if memory obtained from sqlite3_malloc() */
+  u8 needDestroy;     /* True if apMem[]s should be destroyed on close */
+  Mem *aMem;          /* Values */
+};
+
+/*
+** The following are allowed values for Vdbe.magic
+*/
+#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
+#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */
+#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
+#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */
+
+/*
+** Function prototypes
+*/
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *, Cursor*);
+void sqliteVdbePopStack(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(Cursor*);
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE*, int, Op*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeSerialTypeLen(u32);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem*, int);
+SQLITE_PRIVATE int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
+SQLITE_PRIVATE int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
+
+int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord *,int,const unsigned char*,int*);
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
+SQLITE_PRIVATE int sqlite3VdbeIdxRowidLen(const u8*);
+SQLITE_PRIVATE int sqlite3VdbeExec(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeList(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *, int);
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
+SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem*, double);
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemDynamicify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, int);
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
+SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int, int);
+SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+SQLITE_PRIVATE int sqlite3VdbeReleaseBuffers(Vdbe *p);
+#endif
+
+#ifndef NDEBUG
+SQLITE_PRIVATE   void sqlite3VdbeMemSanity(Mem*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem*, u8);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
+SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem);
+SQLITE_PRIVATE void sqlite3VdbeFifoInit(Fifo*);
+SQLITE_PRIVATE int sqlite3VdbeFifoPush(Fifo*, i64);
+SQLITE_PRIVATE int sqlite3VdbeFifoPop(Fifo*, i64*);
+SQLITE_PRIVATE void sqlite3VdbeFifoClear(Fifo*);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
+#else
+  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
+#endif
+
+#endif /* !defined(_VDBEINT_H_) */
+
+/************** End of vdbeInt.h *********************************************/
+/************** Continuing where we left off in utf.c ************************/
+
+/*
+** The following constant value is used by the SQLITE_BIGENDIAN and
+** SQLITE_LITTLEENDIAN macros.
+*/
+SQLITE_PRIVATE const int sqlite3one = 1;
+
+/*
+** This lookup table is used to help decode the first byte of
+** a multi-byte UTF8 character.
+*/
+static const unsigned char sqlite3UtfTrans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (c&0xFF);                                \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + ((c>>6)&0x1F);                    \
+    *zOut++ = 0x80 + (c & 0x3F);                       \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + ((c>>12)&0x0F);                   \
+    *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \
+    *zOut++ = 0x80 + (c & 0x3F);                       \
+  }else{                                               \
+    *zOut++ = 0xF0 + ((c>>18) & 0x07);                 \
+    *zOut++ = 0x80 + ((c>>12) & 0x3F);                 \
+    *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \
+    *zOut++ = 0x80 + (c & 0x3F);                       \
+  }                                                    \
+}
+
+#define WRITE_UTF16LE(zOut, c) {                                \
+  if( c<=0xFFFF ){                                              \
+    *zOut++ = (c&0x00FF);                                       \
+    *zOut++ = ((c>>8)&0x00FF);                                  \
+  }else{                                                        \
+    *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (c&0x00FF);                                       \
+    *zOut++ = (0x00DC + ((c>>8)&0x03));                         \
+  }                                                             \
+}
+
+#define WRITE_UTF16BE(zOut, c) {                                \
+  if( c<=0xFFFF ){                                              \
+    *zOut++ = ((c>>8)&0x00FF);                                  \
+    *zOut++ = (c&0x00FF);                                       \
+  }else{                                                        \
+    *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (0x00DC + ((c>>8)&0x03));                         \
+    *zOut++ = (c&0x00FF);                                       \
+  }                                                             \
+}
+
+#define READ_UTF16LE(zIn, c){                                         \
+  c = (*zIn++);                                                       \
+  c += ((*zIn++)<<8);                                                 \
+  if( c>=0xD800 && c<0xE000 ){                                       \
+    int c2 = (*zIn++);                                                \
+    c2 += ((*zIn++)<<8);                                              \
+    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
+    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
+  }                                                                   \
+}
+
+#define READ_UTF16BE(zIn, c){                                         \
+  c = ((*zIn++)<<8);                                                  \
+  c += (*zIn++);                                                      \
+  if( c>=0xD800 && c<0xE000 ){                                       \
+    int c2 = ((*zIn++)<<8);                                           \
+    c2 += (*zIn++);                                                   \
+    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
+    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
+  }                                                                   \
+}
+
+/*
+** Translate a single UTF-8 character.  Return the unicode value.
+**
+** During translation, assume that the byte that zTerm points
+** is a 0x00.
+**
+** Write a pointer to the next unread byte back into *pzNext.
+**
+** Notes On Invalid UTF-8:
+**
+**  *  This routine never allows a 7-bit character (0x00 through 0x7f) to
+**     be encoded as a multi-byte character.  Any multi-byte character that
+**     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
+**
+**  *  This routine never allows a UTF16 surrogate value to be encoded.
+**     If a multi-byte character attempts to encode a value between
+**     0xd800 and 0xe000 then it is rendered as 0xfffd.
+**
+**  *  Bytes in the range of 0x80 through 0xbf which occur as the first
+**     byte of a character are interpreted as single-byte characters
+**     and rendered as themselves even though they are technically
+**     invalid characters.
+**
+**  *  This routine accepts an infinite number of different UTF8 encodings
+**     for unicode values 0x80 and greater.  It do not change over-length
+**     encodings to 0xfffd as some systems recommend.
+*/
+SQLITE_PRIVATE int sqlite3Utf8Read(
+  const unsigned char *z,         /* First byte of UTF-8 character */
+  const unsigned char *zTerm,     /* Pretend this byte is 0x00 */
+  const unsigned char **pzNext    /* Write first byte past UTF-8 char here */
+){
+  int c = *(z++);
+  if( c>=0xc0 ){
+    c = sqlite3UtfTrans1[c-0xc0];
+    while( z!=zTerm && (*z & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & *(z++));
+    }
+    if( c<0x80
+        || (c&0xFFFFF800)==0xD800
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }
+  }
+  *pzNext = z;
+  return c;
+}
+
+
+
+/*
+** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
+** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
+*/ 
+/* #define TRANSLATE_TRACE 1 */
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine transforms the internal text encoding used by pMem to
+** desiredEnc. It is an error if the string is already of the desired
+** encoding, or if *pMem does not contain a string value.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
+  int len;                    /* Maximum length of output string in bytes */
+  unsigned char *zOut;                  /* Output buffer */
+  unsigned char *zIn;                   /* Input iterator */
+  unsigned char *zTerm;                 /* End of input */
+  unsigned char *z;                     /* Output iterator */
+  unsigned int c;
+
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( pMem->flags&MEM_Str );
+  assert( pMem->enc!=desiredEnc );
+  assert( pMem->enc!=0 );
+  assert( pMem->n>=0 );
+
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    char zBuf[100];
+    sqlite3VdbeMemPrettyPrint(pMem, zBuf);
+    fprintf(stderr, "INPUT:  %s\n", zBuf);
+  }
+#endif
+
+  /* If the translation is between UTF-16 little and big endian, then 
+  ** all that is required is to swap the byte order. This case is handled
+  ** differently from the others.
+  */
+  if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){
+    u8 temp;
+    int rc;
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc!=SQLITE_OK ){
+      assert( rc==SQLITE_NOMEM );
+      return SQLITE_NOMEM;
+    }
+    zIn = (u8*)pMem->z;
+    zTerm = &zIn[pMem->n];
+    while( zIn<zTerm ){
+      temp = *zIn;
+      *zIn = *(zIn+1);
+      zIn++;
+      *zIn++ = temp;
+    }
+    pMem->enc = desiredEnc;
+    goto translate_out;
+  }
+
+  /* Set len to the maximum number of bytes required in the output buffer. */
+  if( desiredEnc==SQLITE_UTF8 ){
+    /* When converting from UTF-16, the maximum growth results from
+    ** translating a 2-byte character to a 4-byte UTF-8 character.
+    ** A single byte is required for the output string
+    ** nul-terminator.
+    */
+    len = pMem->n * 2 + 1;
+  }else{
+    /* When converting from UTF-8 to UTF-16 the maximum growth is caused
+    ** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16
+    ** character. Two bytes are required in the output buffer for the
+    ** nul-terminator.
+    */
+    len = pMem->n * 2 + 2;
+  }
+
+  /* Set zIn to point at the start of the input buffer and zTerm to point 1
+  ** byte past the end.
+  **
+  ** Variable zOut is set to point at the output buffer, space obtained
+  ** from sqlite3_malloc().
+  */
+  zIn = (u8*)pMem->z;
+  zTerm = &zIn[pMem->n];
+  zOut = sqlite3DbMallocRaw(pMem->db, len);
+  if( !zOut ){
+    return SQLITE_NOMEM;
+  }
+  z = zOut;
+
+  if( pMem->enc==SQLITE_UTF8 ){
+    if( desiredEnc==SQLITE_UTF16LE ){
+      /* UTF-8 -> UTF-16 Little-endian */
+      while( zIn<zTerm ){
+        c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
+        WRITE_UTF16LE(z, c);
+      }
+    }else{
+      assert( desiredEnc==SQLITE_UTF16BE );
+      /* UTF-8 -> UTF-16 Big-endian */
+      while( zIn<zTerm ){
+        c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
+        WRITE_UTF16BE(z, c);
+      }
+    }
+    pMem->n = z - zOut;
+    *z++ = 0;
+  }else{
+    assert( desiredEnc==SQLITE_UTF8 );
+    if( pMem->enc==SQLITE_UTF16LE ){
+      /* UTF-16 Little-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        READ_UTF16LE(zIn, c); 
+        WRITE_UTF8(z, c);
+      }
+    }else{
+      /* UTF-16 Little-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        READ_UTF16BE(zIn, c); 
+        WRITE_UTF8(z, c);
+      }
+    }
+    pMem->n = z - zOut;
+  }
+  *z = 0;
+  assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );
+
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags &= ~(MEM_Static|MEM_Dyn|MEM_Ephem);
+  pMem->enc = desiredEnc;
+  pMem->flags |= (MEM_Term|MEM_Dyn);
+  pMem->z = (char*)zOut;
+  pMem->zMalloc = pMem->z;
+
+translate_out:
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    char zBuf[100];
+    sqlite3VdbeMemPrettyPrint(pMem, zBuf);
+    fprintf(stderr, "OUTPUT: %s\n", zBuf);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** This routine checks for a byte-order mark at the beginning of the 
+** UTF-16 string stored in *pMem. If one is present, it is removed and
+** the encoding of the Mem adjusted. This routine does not do any
+** byte-swapping, it just sets Mem.enc appropriately.
+**
+** The allocation (static, dynamic etc.) and encoding of the Mem may be
+** changed by this function.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem){
+  int rc = SQLITE_OK;
+  u8 bom = 0;
+
+  if( pMem->n<0 || pMem->n>1 ){
+    u8 b1 = *(u8 *)pMem->z;
+    u8 b2 = *(((u8 *)pMem->z) + 1);
+    if( b1==0xFE && b2==0xFF ){
+      bom = SQLITE_UTF16BE;
+    }
+    if( b1==0xFF && b2==0xFE ){
+      bom = SQLITE_UTF16LE;
+    }
+  }
+  
+  if( bom ){
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc==SQLITE_OK ){
+      pMem->n -= 2;
+      memmove(pMem->z, &pMem->z[2], pMem->n);
+      pMem->z[pMem->n] = '\0';
+      pMem->z[pMem->n+1] = '\0';
+      pMem->flags |= MEM_Term;
+      pMem->enc = bom;
+    }
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** pZ is a UTF-8 encoded unicode string. If nByte is less than zero,
+** return the number of unicode characters in pZ up to (but not including)
+** the first 0x00 byte. If nByte is not less than zero, return the
+** number of unicode characters in the first nByte of pZ (or up to 
+** the first 0x00, whichever comes first).
+*/
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *zIn, int nByte){
+  int r = 0;
+  const u8 *z = (const u8*)zIn;
+  const u8 *zTerm;
+  if( nByte>=0 ){
+    zTerm = &z[nByte];
+  }else{
+    zTerm = (const u8*)(-1);
+  }
+  assert( z<=zTerm );
+  while( *z!=0 && z<zTerm ){
+    SQLITE_SKIP_UTF8(z);
+    r++;
+  }
+  return r;
+}
+
+/* This test function is not currently used by the automated test-suite. 
+** Hence it is only available in debug builds.
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Translate UTF-8 to UTF-8.
+**
+** This has the effect of making sure that the string is well-formed
+** UTF-8.  Miscoded characters are removed.
+**
+** The translation is done in-place (since it is impossible for the
+** correct UTF-8 encoding to be longer than a malformed encoding).
+*/
+SQLITE_PRIVATE int sqlite3Utf8To8(unsigned char *zIn){
+  unsigned char *zOut = zIn;
+  unsigned char *zStart = zIn;
+  unsigned char *zTerm;
+  u32 c;
+
+  while( zIn[0] ){
+    c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
+    if( c!=0xfffd ){
+      WRITE_UTF8(zOut, c);
+    }
+  }
+  *zOut = 0;
+  return zOut - zStart;
+}
+#endif
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Convert a UTF-16 string in the native encoding into a UTF-8 string.
+** Memory to hold the UTF-8 string is obtained from sqlite3_malloc and must
+** be freed by the calling function.
+**
+** NULL is returned if there is an allocation error.
+*/
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte){
+  Mem m;
+  memset(&m, 0, sizeof(m));
+  m.db = db;
+  sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
+  if( db->mallocFailed ){
+    sqlite3VdbeMemRelease(&m);
+    m.z = 0;
+  }
+  assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );
+  assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );
+  return (m.flags & MEM_Dyn)!=0 ? m.z : sqlite3DbStrDup(db, m.z);
+}
+
+/*
+** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,
+** return the number of bytes up to (but not including), the first pair
+** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,
+** then return the number of bytes in the first nChar unicode characters
+** in pZ (or up until the first pair of 0x00 bytes, whichever comes first).
+*/
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *zIn, int nChar){
+  unsigned int c = 1;
+  char const *z = zIn;
+  int n = 0;
+  if( SQLITE_UTF16NATIVE==SQLITE_UTF16BE ){
+    /* Using an "if (SQLITE_UTF16NATIVE==SQLITE_UTF16BE)" construct here
+    ** and in other parts of this file means that at one branch will
+    ** not be covered by coverage testing on any single host. But coverage
+    ** will be complete if the tests are run on both a little-endian and 
+    ** big-endian host. Because both the UTF16NATIVE and SQLITE_UTF16BE
+    ** macros are constant at compile time the compiler can determine
+    ** which branch will be followed. It is therefore assumed that no runtime
+    ** penalty is paid for this "if" statement.
+    */
+    while( c && ((nChar<0) || n<nChar) ){
+      READ_UTF16BE(z, c);
+      n++;
+    }
+  }else{
+    while( c && ((nChar<0) || n<nChar) ){
+      READ_UTF16LE(z, c);
+      n++;
+    }
+  }
+  return (z-(char const *)zIn)-((c==0)?2:0);
+}
+
+#if defined(SQLITE_TEST)
+/*
+** This routine is called from the TCL test function "translate_selftest".
+** It checks that the primitives for serializing and deserializing
+** characters in each encoding are inverses of each other.
+*/
+SQLITE_PRIVATE void sqlite3UtfSelfTest(){
+  unsigned int i, t;
+  unsigned char zBuf[20];
+  unsigned char *z;
+  unsigned char *zTerm;
+  int n;
+  unsigned int c;
+
+  for(i=0; i<0x00110000; i++){
+    z = zBuf;
+    WRITE_UTF8(z, i);
+    n = z-zBuf;
+    z[0] = 0;
+    zTerm = z;
+    z = zBuf;
+    c = sqlite3Utf8Read(z, zTerm, (const u8**)&z);
+    t = i;
+    if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
+    if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
+    assert( c==t );
+    assert( (z-zBuf)==n );
+  }
+  for(i=0; i<0x00110000; i++){
+    if( i>=0xD800 && i<0xE000 ) continue;
+    z = zBuf;
+    WRITE_UTF16LE(z, i);
+    n = z-zBuf;
+    z[0] = 0;
+    z = zBuf;
+    READ_UTF16LE(z, c);
+    assert( c==i );
+    assert( (z-zBuf)==n );
+  }
+  for(i=0; i<0x00110000; i++){
+    if( i>=0xD800 && i<0xE000 ) continue;
+    z = zBuf;
+    WRITE_UTF16BE(z, i);
+    n = z-zBuf;
+    z[0] = 0;
+    z = zBuf;
+    READ_UTF16BE(z, c);
+    assert( c==i );
+    assert( (z-zBuf)==n );
+  }
+}
+#endif /* SQLITE_TEST */
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of utf.c *************************************************/
+/************** Begin file util.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Utility functions used throughout sqlite.
+**
+** This file contains functions for allocating memory, comparing
+** strings, and stuff like that.
+**
+** $Id: util.c,v 1.229 2008/05/13 16:41:50 drh Exp $
+*/
+
+
+/*
+** Return true if the floating point value is Not a Number.
+*/
+SQLITE_PRIVATE int sqlite3IsNaN(double x){
+  /* This NaN test sometimes fails if compiled on GCC with -ffast-math.
+  ** On the other hand, the use of -ffast-math comes with the following
+  ** warning:
+  **
+  **      This option [-ffast-math] should never be turned on by any
+  **      -O option since it can result in incorrect output for programs
+  **      which depend on an exact implementation of IEEE or ISO 
+  **      rules/specifications for math functions.
+  */
+  volatile double y = x;
+  return x!=y;
+}
+
+/*
+** Set the most recent error code and error string for the sqlite
+** handle "db". The error code is set to "err_code".
+**
+** If it is not NULL, string zFormat specifies the format of the
+** error string in the style of the printf functions: The following
+** format characters are allowed:
+**
+**      %s      Insert a string
+**      %z      A string that should be freed after use
+**      %d      Insert an integer
+**      %T      Insert a token
+**      %S      Insert the first element of a SrcList
+**
+** zFormat and any string tokens that follow it are assumed to be
+** encoded in UTF-8.
+**
+** To clear the most recent error for sqlite handle "db", sqlite3Error
+** should be called with err_code set to SQLITE_OK and zFormat set
+** to NULL.
+*/
+SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code, const char *zFormat, ...){
+  if( db && (db->pErr || (db->pErr = sqlite3ValueNew(db))!=0) ){
+    db->errCode = err_code;
+    if( zFormat ){
+      char *z;
+      va_list ap;
+      va_start(ap, zFormat);
+      z = sqlite3VMPrintf(db, zFormat, ap);
+      va_end(ap);
+      sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, sqlite3_free);
+    }else{
+      sqlite3ValueSetStr(db->pErr, 0, 0, SQLITE_UTF8, SQLITE_STATIC);
+    }
+  }
+}
+
+/*
+** Add an error message to pParse->zErrMsg and increment pParse->nErr.
+** The following formatting characters are allowed:
+**
+**      %s      Insert a string
+**      %z      A string that should be freed after use
+**      %d      Insert an integer
+**      %T      Insert a token
+**      %S      Insert the first element of a SrcList
+**
+** This function should be used to report any error that occurs whilst
+** compiling an SQL statement (i.e. within sqlite3_prepare()). The
+** last thing the sqlite3_prepare() function does is copy the error
+** stored by this function into the database handle using sqlite3Error().
+** Function sqlite3Error() should be used during statement execution
+** (sqlite3_step() etc.).
+*/
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
+  va_list ap;
+  pParse->nErr++;
+  sqlite3_free(pParse->zErrMsg);
+  va_start(ap, zFormat);
+  pParse->zErrMsg = sqlite3VMPrintf(pParse->db, zFormat, ap);
+  va_end(ap);
+  if( pParse->rc==SQLITE_OK ){
+    pParse->rc = SQLITE_ERROR;
+  }
+}
+
+/*
+** Clear the error message in pParse, if any
+*/
+SQLITE_PRIVATE void sqlite3ErrorClear(Parse *pParse){
+  sqlite3_free(pParse->zErrMsg);
+  pParse->zErrMsg = 0;
+  pParse->nErr = 0;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** 2002-Feb-14: This routine is extended to remove MS-Access style
+** brackets from around identifers.  For example:  "[a-b-c]" becomes
+** "a-b-c".
+*/
+SQLITE_PRIVATE void sqlite3Dequote(char *z){
+  int quote;
+  int i, j;
+  if( z==0 ) return;
+  quote = z[0];
+  switch( quote ){
+    case '\'':  break;
+    case '"':   break;
+    case '`':   break;                /* For MySQL compatibility */
+    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
+    default:    return;
+  }
+  for(i=1, j=0; z[i]; i++){
+    if( z[i]==quote ){
+      if( z[i+1]==quote ){
+        z[j++] = quote;
+        i++;
+      }else{
+        z[j++] = 0;
+        break;
+      }
+    }else{
+      z[j++] = z[i];
+    }
+  }
+}
+
+/* An array to map all upper-case characters into their corresponding
+** lower-case character. 
+*/
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[] = {
+#ifdef SQLITE_ASCII
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
+     18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
+     36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
+     54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103,
+    104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,
+    122, 91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107,
+    108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,
+    126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,
+    162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,
+    180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,
+    198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,
+    216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,
+    234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,
+    252,253,254,255
+#endif
+#ifdef SQLITE_EBCDIC
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, /* 0x */
+     16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 1x */
+     32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, /* 2x */
+     48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, /* 3x */
+     64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, /* 4x */
+     80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, /* 5x */
+     96, 97, 66, 67, 68, 69, 70, 71, 72, 73,106,107,108,109,110,111, /* 6x */
+    112, 81, 82, 83, 84, 85, 86, 87, 88, 89,122,123,124,125,126,127, /* 7x */
+    128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, /* 8x */
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,156,159, /* 9x */
+    160,161,162,163,164,165,166,167,168,169,170,171,140,141,142,175, /* Ax */
+    176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191, /* Bx */
+    192,129,130,131,132,133,134,135,136,137,202,203,204,205,206,207, /* Cx */
+    208,145,146,147,148,149,150,151,152,153,218,219,220,221,222,223, /* Dx */
+    224,225,162,163,164,165,166,167,168,169,232,203,204,205,206,207, /* Ex */
+    239,240,241,242,243,244,245,246,247,248,249,219,220,221,222,255, /* Fx */
+#endif
+};
+#define UpperToLower sqlite3UpperToLower
+
+/*
+** Some systems have stricmp().  Others have strcasecmp().  Because
+** there is no consistency, we will define our own.
+*/
+SQLITE_PRIVATE int sqlite3StrICmp(const char *zLeft, const char *zRight){
+  register unsigned char *a, *b;
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
+  return UpperToLower[*a] - UpperToLower[*b];
+}
+SQLITE_PRIVATE int sqlite3StrNICmp(const char *zLeft, const char *zRight, int N){
+  register unsigned char *a, *b;
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
+  return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
+}
+
+/*
+** Return TRUE if z is a pure numeric string.  Return FALSE if the
+** string contains any character which is not part of a number. If
+** the string is numeric and contains the '.' character, set *realnum
+** to TRUE (otherwise FALSE).
+**
+** An empty string is considered non-numeric.
+*/
+SQLITE_PRIVATE int sqlite3IsNumber(const char *z, int *realnum, u8 enc){
+  int incr = (enc==SQLITE_UTF8?1:2);
+  if( enc==SQLITE_UTF16BE ) z++;
+  if( *z=='-' || *z=='+' ) z += incr;
+  if( !isdigit(*(u8*)z) ){
+    return 0;
+  }
+  z += incr;
+  if( realnum ) *realnum = 0;
+  while( isdigit(*(u8*)z) ){ z += incr; }
+  if( *z=='.' ){
+    z += incr;
+    if( !isdigit(*(u8*)z) ) return 0;
+    while( isdigit(*(u8*)z) ){ z += incr; }
+    if( realnum ) *realnum = 1;
+  }
+  if( *z=='e' || *z=='E' ){
+    z += incr;
+    if( *z=='+' || *z=='-' ) z += incr;
+    if( !isdigit(*(u8*)z) ) return 0;
+    while( isdigit(*(u8*)z) ){ z += incr; }
+    if( realnum ) *realnum = 1;
+  }
+  return *z==0;
+}
+
+/*
+** The string z[] is an ascii representation of a real number.
+** Convert this string to a double.
+**
+** This routine assumes that z[] really is a valid number.  If it
+** is not, the result is undefined.
+**
+** This routine is used instead of the library atof() function because
+** the library atof() might want to use "," as the decimal point instead
+** of "." depending on how locale is set.  But that would cause problems
+** for SQL.  So this routine always uses "." regardless of locale.
+*/
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  int sign = 1;
+  const char *zBegin = z;
+  LONGDOUBLE_TYPE v1 = 0.0;
+  int nSignificant = 0;
+  while( isspace(*(u8*)z) ) z++;
+  if( *z=='-' ){
+    sign = -1;
+    z++;
+  }else if( *z=='+' ){
+    z++;
+  }
+  while( z[0]=='0' ){
+    z++;
+  }
+  while( isdigit(*(u8*)z) ){
+    v1 = v1*10.0 + (*z - '0');
+    z++;
+    nSignificant++;
+  }
+  if( *z=='.' ){
+    LONGDOUBLE_TYPE divisor = 1.0;
+    z++;
+    if( nSignificant==0 ){
+      while( z[0]=='0' ){
+        divisor *= 10.0;
+        z++;
+      }
+    }
+    while( isdigit(*(u8*)z) ){
+      if( nSignificant<18 ){
+        v1 = v1*10.0 + (*z - '0');
+        divisor *= 10.0;
+        nSignificant++;
+      }
+      z++;
+    }
+    v1 /= divisor;
+  }
+  if( *z=='e' || *z=='E' ){
+    int esign = 1;
+    int eval = 0;
+    LONGDOUBLE_TYPE scale = 1.0;
+    z++;
+    if( *z=='-' ){
+      esign = -1;
+      z++;
+    }else if( *z=='+' ){
+      z++;
+    }
+    while( isdigit(*(u8*)z) ){
+      eval = eval*10 + *z - '0';
+      z++;
+    }
+    while( eval>=64 ){ scale *= 1.0e+64; eval -= 64; }
+    while( eval>=16 ){ scale *= 1.0e+16; eval -= 16; }
+    while( eval>=4 ){ scale *= 1.0e+4; eval -= 4; }
+    while( eval>=1 ){ scale *= 1.0e+1; eval -= 1; }
+    if( esign<0 ){
+      v1 /= scale;
+    }else{
+      v1 *= scale;
+    }
+  }
+  *pResult = sign<0 ? -v1 : v1;
+  return z - zBegin;
+#else
+  return sqlite3Atoi64(z, pResult);
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+}
+
+/*
+** Compare the 19-character string zNum against the text representation
+** value 2^63:  9223372036854775808.  Return negative, zero, or positive
+** if zNum is less than, equal to, or greater than the string.
+**
+** Unlike memcmp() this routine is guaranteed to return the difference
+** in the values of the last digit if the only difference is in the
+** last digit.  So, for example,
+**
+**      compare2pow63("9223372036854775800")
+**
+** will return -8.
+*/
+static int compare2pow63(const char *zNum){
+  int c;
+  c = memcmp(zNum,"922337203685477580",18);
+  if( c==0 ){
+    c = zNum[18] - '8';
+  }
+  return c;
+}
+
+
+/*
+** Return TRUE if zNum is a 64-bit signed integer and write
+** the value of the integer into *pNum.  If zNum is not an integer
+** or is an integer that is too large to be expressed with 64 bits,
+** then return false.
+**
+** When this routine was originally written it dealt with only
+** 32-bit numbers.  At that time, it was much faster than the
+** atoi() library routine in RedHat 7.2.
+*/
+SQLITE_PRIVATE int sqlite3Atoi64(const char *zNum, i64 *pNum){
+  i64 v = 0;
+  int neg;
+  int i, c;
+  while( isspace(*(u8*)zNum) ) zNum++;
+  if( *zNum=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( *zNum=='+' ){
+    neg = 0;
+    zNum++;
+  }else{
+    neg = 0;
+  }
+  while( zNum[0]=='0' ){ zNum++; } /* Skip over leading zeros. Ticket #2454 */
+  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){
+    v = v*10 + c - '0';
+  }
+  *pNum = neg ? -v : v;
+  if( c!=0 || i==0 || i>19 ){
+    /* zNum is empty or contains non-numeric text or is longer
+    ** than 19 digits (thus guaranting that it is too large) */
+    return 0;
+  }else if( i<19 ){
+    /* Less than 19 digits, so we know that it fits in 64 bits */
+    return 1;
+  }else{
+    /* 19-digit numbers must be no larger than 9223372036854775807 if positive
+    ** or 9223372036854775808 if negative.  Note that 9223372036854665808
+    ** is 2^63. */
+    return compare2pow63(zNum)<neg;
+  }
+}
+
+/*
+** The string zNum represents an integer.  There might be some other
+** information following the integer too, but that part is ignored.
+** If the integer that the prefix of zNum represents will fit in a
+** 64-bit signed integer, return TRUE.  Otherwise return FALSE.
+**
+** This routine returns FALSE for the string -9223372036854775808 even that
+** that number will, in theory fit in a 64-bit integer.  Positive
+** 9223373036854775808 will not fit in 64 bits.  So it seems safer to return
+** false.
+*/
+SQLITE_PRIVATE int sqlite3FitsIn64Bits(const char *zNum, int negFlag){
+  int i, c;
+  int neg = 0;
+  if( *zNum=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( *zNum=='+' ){
+    zNum++;
+  }
+  if( negFlag ) neg = 1-neg;
+  while( *zNum=='0' ){
+    zNum++;   /* Skip leading zeros.  Ticket #2454 */
+  }
+  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){}
+  if( i<19 ){
+    /* Guaranteed to fit if less than 19 digits */
+    return 1;
+  }else if( i>19 ){
+    /* Guaranteed to be too big if greater than 19 digits */
+    return 0;
+  }else{
+    /* Compare against 2^63. */
+    return compare2pow63(zNum)<neg;
+  }
+}
+
+/*
+** If zNum represents an integer that will fit in 32-bits, then set
+** *pValue to that integer and return true.  Otherwise return false.
+**
+** Any non-numeric characters that following zNum are ignored.
+** This is different from sqlite3Atoi64() which requires the
+** input number to be zero-terminated.
+*/
+SQLITE_PRIVATE int sqlite3GetInt32(const char *zNum, int *pValue){
+  sqlite_int64 v = 0;
+  int i, c;
+  int neg = 0;
+  if( zNum[0]=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( zNum[0]=='+' ){
+    zNum++;
+  }
+  while( zNum[0]=='0' ) zNum++;
+  for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
+    v = v*10 + c;
+  }
+
+  /* The longest decimal representation of a 32 bit integer is 10 digits:
+  **
+  **             1234567890
+  **     2^31 -> 2147483648
+  */
+  if( i>10 ){
+    return 0;
+  }
+  if( v-neg>2147483647 ){
+    return 0;
+  }
+  if( neg ){
+    v = -v;
+  }
+  *pValue = (int)v;
+  return 1;
+}
+
+/*
+** The variable-length integer encoding is as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**         C = xxxxxxxx    8 bits of data
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** 28 bits - BBBA
+** 35 bits - BBBBA
+** 42 bits - BBBBBA
+** 49 bits - BBBBBBA
+** 56 bits - BBBBBBBA
+** 64 bits - BBBBBBBBC
+*/
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data write will be between 1 and 9 bytes.  The number
+** of bytes written is returned.
+**
+** A variable-length integer consists of the lower 7 bits of each byte
+** for all bytes that have the 8th bit set and one byte with the 8th
+** bit clear.  Except, if we get to the 9th byte, it stores the full
+** 8 bits and is the last byte.
+*/
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char *p, u64 v){
+  int i, j, n;
+  u8 buf[10];
+  if( v & (((u64)0xff000000)<<32) ){
+    p[8] = v;
+    v >>= 8;
+    for(i=7; i>=0; i--){
+      p[i] = (v & 0x7f) | 0x80;
+      v >>= 7;
+    }
+    return 9;
+  }    
+  n = 0;
+  do{
+    buf[n++] = (v & 0x7f) | 0x80;
+    v >>= 7;
+  }while( v!=0 );
+  buf[0] &= 0x7f;
+  assert( n<=9 );
+  for(i=0, j=n-1; j>=0; j--, i++){
+    p[i] = buf[j];
+  }
+  return n;
+}
+
+/*
+** This routine is a faster version of sqlite3PutVarint() that only
+** works for 32-bit positive integers and which is optimized for
+** the common case of small integers.  A MACRO version, putVarint32,
+** is provided which inlines the single-byte case.  All code should use
+** the MACRO version as this function assumes the single-byte case has
+** already been handled.
+*/
+SQLITE_PRIVATE int sqlite3PutVarint32(unsigned char *p, u32 v){
+#ifndef putVarint32
+  if( (v & ~0x7f)==0 ){
+    p[0] = v;
+    return 1;
+  }
+#endif
+  if( (v & ~0x3fff)==0 ){
+    p[0] = (v>>7) | 0x80;
+    p[1] = v & 0x7f;
+    return 2;
+  }
+  return sqlite3PutVarint(p, v);
+}
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3GetVarint(const unsigned char *p, u64 *v){
+  u32 a,b,s;
+
+  a = *p;
+  /* a: p0 (unmasked)*/
+  if (!(a&0x80))
+  {
+    *v = a;
+    return 1;
+  }
+
+  p++;
+  b = *p;
+  /* b: p1 (unmasked)*/
+  if (!(b&0x80))
+  {
+    a &= 0x7f;
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 2;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked)*/
+  if (!(a&0x80))
+  {
+    a &= (0x7f<<14)|(0x7f);
+    b &= 0x7f;
+    b = b<<7;
+    a |= b;
+    *v = a;
+    return 3;
+  }
+
+  /* CSE1 from below*/
+  a &= (0x7f<<14)|(0x7f);
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked)*/
+  if (!(b&0x80))
+  {
+    b &= (0x7f<<14)|(0x7f);
+    /* moved CSE1 up*/
+    /* a &= (0x7f<<14)|(0x7f);*/
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 4;
+  }
+
+  /* a: p0<<14 | p2 (masked)*/
+  /* b: p1<<14 | p3 (unmasked)*/
+  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked)*/
+  /* moved CSE1 up*/
+  /* a &= (0x7f<<14)|(0x7f);*/
+  b &= (0x7f<<14)|(0x7f);
+  s = a;
+  /* s: p0<<14 | p2 (masked)*/
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked)*/
+  if (!(a&0x80))
+  {
+    /* we can skip these cause they were (effectively) done above in calc'ing s*/
+    /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f);*/
+    /* b &= (0x7f<<14)|(0x7f);*/
+    b = b<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 5;
+  }
+
+  /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked)*/
+  s = s<<7;
+  s |= b;
+  /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked)*/
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<28 | p3<<14 | p5 (unmasked)*/
+  if (!(b&0x80))
+  {
+    /* we can skip this cause it was (effectively) done above in calc'ing s*/
+    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f);*/
+    a &= (0x7f<<14)|(0x7f);
+    a = a<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 6;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p2<<28 | p4<<14 | p6 (unmasked)*/
+  if (!(a&0x80))
+  {
+    a &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    b &= (0x7f<<14)|(0x7f);
+    b = b<<7;
+    a |= b;
+    s = s>>11;
+    *v = ((u64)s)<<32 | a;
+    return 7;
+  }
+
+  /* CSE2 from below*/
+  a &= (0x7f<<14)|(0x7f);
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p3<<28 | p5<<14 | p7 (unmasked)*/
+  if (!(b&0x80))
+  {
+    b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    /* moved CSE2 up*/
+    /* a &= (0x7f<<14)|(0x7f);*/
+    a = a<<7;
+    a |= b;
+    s = s>>4;
+    *v = ((u64)s)<<32 | a;
+    return 8;
+  }
+
+  p++;
+  a = a<<15;
+  a |= *p;
+  /* a: p4<<29 | p6<<15 | p8 (unmasked)*/
+
+  /* moved CSE2 up*/
+  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff);*/
+  b &= (0x7f<<14)|(0x7f);
+  b = b<<8;
+  a |= b;
+
+  s = s<<4;
+  b = p[-4];
+  b &= 0x7f;
+  b = b>>3;
+  s |= b;
+
+  *v = ((u64)s)<<32 | a;
+
+  return 9;
+}
+
+/*
+** Read a 32-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+** A MACRO version, getVarint32, is provided which inlines the 
+** single-byte case.  All code should use the MACRO version as 
+** this function assumes the single-byte case has already been handled.
+*/
+SQLITE_PRIVATE int sqlite3GetVarint32(const unsigned char *p, u32 *v){
+  u32 a,b;
+
+  a = *p;
+  /* a: p0 (unmasked)*/
+#ifndef getVarint32
+  if (!(a&0x80))
+  {
+    *v = a;
+    return 1;
+  }
+#endif
+
+  p++;
+  b = *p;
+  /* b: p1 (unmasked)*/
+  if (!(b&0x80))
+  {
+    a &= 0x7f;
+    a = a<<7;
+    *v = a | b;
+    return 2;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked)*/
+  if (!(a&0x80))
+  {
+    a &= (0x7f<<14)|(0x7f);
+    b &= 0x7f;
+    b = b<<7;
+    *v = a | b;
+    return 3;
+  }
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked)*/
+  if (!(b&0x80))
+  {
+    b &= (0x7f<<14)|(0x7f);
+    a &= (0x7f<<14)|(0x7f);
+    a = a<<7;
+    *v = a | b;
+    return 4;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked)*/
+  if (!(a&0x80))
+  {
+    a &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    b = b<<7;
+    *v = a | b;
+    return 5;
+  }
+
+  /* We can only reach this point when reading a corrupt database
+  ** file.  In that case we are not in any hurry.  Use the (relatively
+  ** slow) general-purpose sqlite3GetVarint() routine to extract the
+  ** value. */
+  {
+    u64 v64;
+    int n;
+
+    p -= 4;
+    n = sqlite3GetVarint(p, &v64);
+    assert( n>5 && n<=9 );
+    *v = (u32)v64;
+    return n;
+  }
+}
+
+/*
+** Return the number of bytes that will be needed to store the given
+** 64-bit integer.
+*/
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v){
+  int i = 0;
+  do{
+    i++;
+    v >>= 7;
+  }while( v!=0 && i<9 );
+  return i;
+}
+
+
+/*
+** Read or write a four-byte big-endian integer value.
+*/
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8 *p){
+  return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
+}
+SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){
+  p[0] = v>>24;
+  p[1] = v>>16;
+  p[2] = v>>8;
+  p[3] = v;
+}
+
+
+
+#if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
+/*
+** Translate a single byte of Hex into an integer.
+** This routinen only works if h really is a valid hexadecimal
+** character:  0..9a..fA..F
+*/
+static int hexToInt(int h){
+  assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
+#ifdef SQLITE_ASCII
+  h += 9*(1&(h>>6));
+#endif
+#ifdef SQLITE_EBCDIC
+  h += 9*(1&~(h>>4));
+#endif
+  return h & 0xf;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
+
+#if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
+/*
+** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
+** value.  Return a pointer to its binary value.  Space to hold the
+** binary value has been obtained from malloc and must be freed by
+** the calling routine.
+*/
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
+  char *zBlob;
+  int i;
+
+  zBlob = (char *)sqlite3DbMallocRaw(db, n/2 + 1);
+  n--;
+  if( zBlob ){
+    for(i=0; i<n; i+=2){
+      zBlob[i/2] = (hexToInt(z[i])<<4) | hexToInt(z[i+1]);
+    }
+    zBlob[i/2] = 0;
+  }
+  return zBlob;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
+
+
+/*
+** Change the sqlite.magic from SQLITE_MAGIC_OPEN to SQLITE_MAGIC_BUSY.
+** Return an error (non-zero) if the magic was not SQLITE_MAGIC_OPEN
+** when this routine is called.
+**
+** This routine is called when entering an SQLite API.  The SQLITE_MAGIC_OPEN
+** value indicates that the database connection passed into the API is
+** open and is not being used by another thread.  By changing the value
+** to SQLITE_MAGIC_BUSY we indicate that the connection is in use.
+** sqlite3SafetyOff() below will change the value back to SQLITE_MAGIC_OPEN
+** when the API exits. 
+**
+** This routine is a attempt to detect if two threads use the
+** same sqlite* pointer at the same time.  There is a race 
+** condition so it is possible that the error is not detected.
+** But usually the problem will be seen.  The result will be an
+** error which can be used to debug the application that is
+** using SQLite incorrectly.
+**
+** Ticket #202:  If db->magic is not a valid open value, take care not
+** to modify the db structure at all.  It could be that db is a stale
+** pointer.  In other words, it could be that there has been a prior
+** call to sqlite3_close(db) and db has been deallocated.  And we do
+** not want to write into deallocated memory.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3SafetyOn(sqlite3 *db){
+  if( db->magic==SQLITE_MAGIC_OPEN ){
+    db->magic = SQLITE_MAGIC_BUSY;
+    assert( sqlite3_mutex_held(db->mutex) );
+    return 0;
+  }else if( db->magic==SQLITE_MAGIC_BUSY ){
+    db->magic = SQLITE_MAGIC_ERROR;
+    db->u1.isInterrupted = 1;
+  }
+  return 1;
+}
+#endif
+
+/*
+** Change the magic from SQLITE_MAGIC_BUSY to SQLITE_MAGIC_OPEN.
+** Return an error (non-zero) if the magic was not SQLITE_MAGIC_BUSY
+** when this routine is called.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3SafetyOff(sqlite3 *db){
+  if( db->magic==SQLITE_MAGIC_BUSY ){
+    db->magic = SQLITE_MAGIC_OPEN;
+    assert( sqlite3_mutex_held(db->mutex) );
+    return 0;
+  }else{
+    db->magic = SQLITE_MAGIC_ERROR;
+    db->u1.isInterrupted = 1;
+    return 1;
+  }
+}
+#endif
+
+/*
+** Check to make sure we have a valid db pointer.  This test is not
+** foolproof but it does provide some measure of protection against
+** misuse of the interface such as passing in db pointers that are
+** NULL or which have been previously closed.  If this routine returns
+** 1 it means that the db pointer is valid and 0 if it should not be
+** dereferenced for any reason.  The calling function should invoke
+** SQLITE_MISUSE immediately.
+**
+** sqlite3SafetyCheckOk() requires that the db pointer be valid for
+** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
+** open properly and is not fit for general use but which can be
+** used as an argument to sqlite3_errmsg() or sqlite3_close().
+*/
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3 *db){
+  int magic;
+  if( db==0 ) return 0;
+  magic = db->magic;
+  if( magic!=SQLITE_MAGIC_OPEN &&
+      magic!=SQLITE_MAGIC_BUSY ) return 0;
+  return 1;
+}
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
+  int magic;
+  if( db==0 ) return 0;
+  magic = db->magic;
+  if( magic!=SQLITE_MAGIC_SICK &&
+      magic!=SQLITE_MAGIC_OPEN &&
+      magic!=SQLITE_MAGIC_BUSY ) return 0;
+  return 1;
+}
+
+/************** End of util.c ************************************************/
+/************** Begin file hash.c ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables
+** used in SQLite.
+**
+** $Id: hash.c,v 1.28 2008/05/13 13:27:34 drh Exp $
+*/
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+** keyClass is one of the constants SQLITE_HASH_INT, SQLITE_HASH_POINTER,
+** SQLITE_HASH_BINARY, or SQLITE_HASH_STRING.  The value of keyClass 
+** determines what kind of key the hash table will use.  "copyKey" is
+** true if the hash table should make its own private copy of keys and
+** false if it should just use the supplied pointer.  CopyKey only makes
+** sense for SQLITE_HASH_STRING and SQLITE_HASH_BINARY and is ignored
+** for other key classes.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash *pNew, int keyClass, int copyKey){
+  assert( pNew!=0 );
+  assert( keyClass>=SQLITE_HASH_STRING && keyClass<=SQLITE_HASH_BINARY );
+  pNew->keyClass = keyClass;
+#if 0
+  if( keyClass==SQLITE_HASH_POINTER || keyClass==SQLITE_HASH_INT ) copyKey = 0;
+#endif
+  pNew->copyKey = copyKey;
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3HashClear(Hash *pH){
+  HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  sqlite3_free(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    HashElem *next_elem = elem->next;
+    if( pH->copyKey && elem->pKey ){
+      sqlite3_free(elem->pKey);
+    }
+    sqlite3_free(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+#if 0 /* NOT USED */
+/*
+** Hash and comparison functions when the mode is SQLITE_HASH_INT
+*/
+static int intHash(const void *pKey, int nKey){
+  return nKey ^ (nKey<<8) ^ (nKey>>8);
+}
+static int intCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  return n2 - n1;
+}
+#endif
+
+#if 0 /* NOT USED */
+/*
+** Hash and comparison functions when the mode is SQLITE_HASH_POINTER
+*/
+static int ptrHash(const void *pKey, int nKey){
+  uptr x = Addr(pKey);
+  return x ^ (x<<8) ^ (x>>8);
+}
+static int ptrCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( pKey1==pKey2 ) return 0;
+  if( pKey1<pKey2 ) return -1;
+  return 1;
+}
+#endif
+
+/*
+** Hash and comparison functions when the mode is SQLITE_HASH_STRING
+*/
+static int strHash(const void *pKey, int nKey){
+  const char *z = (const char *)pKey;
+  int h = 0;
+  if( nKey<=0 ) nKey = strlen(z);
+  while( nKey > 0  ){
+    h = (h<<3) ^ h ^ sqlite3UpperToLower[(unsigned char)*z++];
+    nKey--;
+  }
+  return h & 0x7fffffff;
+}
+static int strCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return sqlite3StrNICmp((const char*)pKey1,(const char*)pKey2,n1);
+}
+
+/*
+** Hash and comparison functions when the mode is SQLITE_HASH_BINARY
+*/
+static int binHash(const void *pKey, int nKey){
+  int h = 0;
+  const char *z = (const char *)pKey;
+  while( nKey-- > 0 ){
+    h = (h<<3) ^ h ^ *(z++);
+  }
+  return h & 0x7fffffff;
+}
+static int binCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return memcmp(pKey1,pKey2,n1);
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** The C syntax in this function definition may be unfamilar to some 
+** programmers, so we provide the following additional explanation:
+**
+** The name of the function is "hashFunction".  The function takes a
+** single parameter "keyClass".  The return value of hashFunction()
+** is a pointer to another function.  Specifically, the return value
+** of hashFunction() is a pointer to a function that takes two parameters
+** with types "const void*" and "int" and returns an "int".
+*/
+static int (*hashFunction(int keyClass))(const void*,int){
+#if 0  /* HASH_INT and HASH_POINTER are never used */
+  switch( keyClass ){
+    case SQLITE_HASH_INT:     return &intHash;
+    case SQLITE_HASH_POINTER: return &ptrHash;
+    case SQLITE_HASH_STRING:  return &strHash;
+    case SQLITE_HASH_BINARY:  return &binHash;;
+    default: break;
+  }
+  return 0;
+#else
+  if( keyClass==SQLITE_HASH_STRING ){
+    return &strHash;
+  }else{
+    assert( keyClass==SQLITE_HASH_BINARY );
+    return &binHash;
+  }
+#endif
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** For help in interpreted the obscure C code in the function definition,
+** see the header comment on the previous function.
+*/
+static int (*compareFunction(int keyClass))(const void*,int,const void*,int){
+#if 0 /* HASH_INT and HASH_POINTER are never used */
+  switch( keyClass ){
+    case SQLITE_HASH_INT:     return &intCompare;
+    case SQLITE_HASH_POINTER: return &ptrCompare;
+    case SQLITE_HASH_STRING:  return &strCompare;
+    case SQLITE_HASH_BINARY:  return &binCompare;
+    default: break;
+  }
+  return 0;
+#else
+  if( keyClass==SQLITE_HASH_STRING ){
+    return &strCompare;
+  }else{
+    assert( keyClass==SQLITE_HASH_BINARY );
+    return &binCompare;
+  }
+#endif
+}
+
+/* Link an element into the hash table
+*/
+static void insertElement(
+  Hash *pH,              /* The complete hash table */
+  struct _ht *pEntry,    /* The entry into which pNew is inserted */
+  HashElem *pNew         /* The element to be inserted */
+){
+  HashElem *pHead;       /* First element already in pEntry */
+  pHead = pEntry->chain;
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+  pEntry->count++;
+  pEntry->chain = pNew;
+}
+
+
+/* Resize the hash table so that it cantains "new_size" buckets.
+** "new_size" must be a power of 2.  The hash table might fail 
+** to resize if sqlite3_malloc() fails.
+*/
+static void rehash(Hash *pH, int new_size){
+  struct _ht *new_ht;            /* The new hash table */
+  HashElem *elem, *next_elem;    /* For looping over existing elements */
+  int (*xHash)(const void*,int); /* The hash function */
+
+#ifdef SQLITE_MALLOC_SOFT_LIMIT
+  if( new_size*sizeof(struct _ht)>SQLITE_MALLOC_SOFT_LIMIT ){
+    new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
+  }
+  if( new_size==pH->htsize ) return;
+#endif
+
+  /* There is a call to sqlite3_malloc() inside rehash(). If there is
+  ** already an allocation at pH->ht, then if this malloc() fails it
+  ** is benign (since failing to resize a hash table is a performance
+  ** hit only, not a fatal error).
+  */
+  if( pH->htsize>0 ) sqlite3FaultBeginBenign(SQLITE_FAULTINJECTOR_MALLOC);
+  new_ht = (struct _ht *)sqlite3MallocZero( new_size*sizeof(struct _ht) );
+  if( pH->htsize>0 ) sqlite3FaultEndBenign(SQLITE_FAULTINJECTOR_MALLOC);
+
+  if( new_ht==0 ) return;
+  sqlite3_free(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size;
+  xHash = hashFunction(pH->keyClass);
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
+    next_elem = elem->next;
+    insertElement(pH, &new_ht[h], elem);
+  }
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  The hash for this key has
+** already been computed and is passed as the 4th parameter.
+*/
+static HashElem *findElementGivenHash(
+  const Hash *pH,     /* The pH to be searched */
+  const void *pKey,   /* The key we are searching for */
+  int nKey,
+  int h               /* The hash for this key. */
+){
+  HashElem *elem;                /* Used to loop thru the element list */
+  int count;                     /* Number of elements left to test */
+  int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
+
+  if( pH->ht ){
+    struct _ht *pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+    xCompare = compareFunction(pH->keyClass);
+    while( count-- && elem ){
+      if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){ 
+        return elem;
+      }
+      elem = elem->next;
+    }
+  }
+  return 0;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void removeElementGivenHash(
+  Hash *pH,         /* The pH containing "elem" */
+  HashElem* elem,   /* The element to be removed from the pH */
+  int h             /* Hash value for the element */
+){
+  struct _ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next; 
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  pEntry = &pH->ht[h];
+  if( pEntry->chain==elem ){
+    pEntry->chain = elem->next;
+  }
+  pEntry->count--;
+  if( pEntry->count<=0 ){
+    pEntry->chain = 0;
+  }
+  if( pH->copyKey ){
+    sqlite3_free(elem->pKey);
+  }
+  sqlite3_free( elem );
+  pH->count--;
+  if( pH->count<=0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    sqlite3HashClear(pH);
+  }
+}
+
+/* Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return a pointer to the corresponding 
+** HashElem structure for this element if it is found, or NULL
+** otherwise.
+*/
+SQLITE_PRIVATE HashElem *sqlite3HashFindElem(const Hash *pH, const void *pKey, int nKey){
+  int h;             /* A hash on key */
+  HashElem *elem;    /* The element that matches key */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  if( pH==0 || pH->ht==0 ) return 0;
+  xHash = hashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  h = (*xHash)(pKey,nKey);
+  elem = findElementGivenHash(pH,pKey,nKey, h % pH->htsize);
+  return elem;
+}
+
+/* Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const void *pKey, int nKey){
+  HashElem *elem;    /* The element that matches key */
+  elem = sqlite3HashFindElem(pH, pKey, nKey);
+  return elem ? elem->data : 0;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey,nKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created.  A copy of the key is made if the copyKey
+** flag is set.  NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const void *pKey, int nKey, void *data){
+  int hraw;             /* Raw hash value of the key */
+  int h;                /* the hash of the key modulo hash table size */
+  HashElem *elem;       /* Used to loop thru the element list */
+  HashElem *new_elem;   /* New element added to the pH */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  assert( pH!=0 );
+  xHash = hashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  hraw = (*xHash)(pKey, nKey);
+  if( pH->htsize ){
+    h = hraw % pH->htsize;
+    elem = findElementGivenHash(pH,pKey,nKey,h);
+    if( elem ){
+      void *old_data = elem->data;
+      if( data==0 ){
+        removeElementGivenHash(pH,elem,h);
+      }else{
+        elem->data = data;
+        if( !pH->copyKey ){
+          elem->pKey = (void *)pKey;
+        }
+        assert(nKey==elem->nKey);
+      }
+      return old_data;
+    }
+  }
+  if( data==0 ) return 0;
+  new_elem = (HashElem*)sqlite3_malloc( sizeof(HashElem) );
+  if( new_elem==0 ) return data;
+  if( pH->copyKey && pKey!=0 ){
+    new_elem->pKey = sqlite3_malloc( nKey );
+    if( new_elem->pKey==0 ){
+      sqlite3_free(new_elem);
+      return data;
+    }
+    memcpy((void*)new_elem->pKey, pKey, nKey);
+  }else{
+    new_elem->pKey = (void*)pKey;
+  }
+  new_elem->nKey = nKey;
+  pH->count++;
+  if( pH->htsize==0 ){
+    rehash(pH, 128/sizeof(pH->ht[0]));
+    if( pH->htsize==0 ){
+      pH->count = 0;
+      if( pH->copyKey ){
+        sqlite3_free(new_elem->pKey);
+      }
+      sqlite3_free(new_elem);
+      return data;
+    }
+  }
+  if( pH->count > pH->htsize ){
+    rehash(pH,pH->htsize*2);
+  }
+  assert( pH->htsize>0 );
+  h = hraw % pH->htsize;
+  insertElement(pH, &pH->ht[h], new_elem);
+  new_elem->data = data;
+  return 0;
+}
+
+/************** End of hash.c ************************************************/
+/************** Begin file opcodes.c *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the mkopcodec.awk script for details. */
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
+ static const char *const azName[] = { "?",
+     /*   1 */ "VNext",
+     /*   2 */ "Affinity",
+     /*   3 */ "Column",
+     /*   4 */ "SetCookie",
+     /*   5 */ "Sequence",
+     /*   6 */ "MoveGt",
+     /*   7 */ "RowKey",
+     /*   8 */ "SCopy",
+     /*   9 */ "OpenWrite",
+     /*  10 */ "If",
+     /*  11 */ "VRowid",
+     /*  12 */ "CollSeq",
+     /*  13 */ "OpenRead",
+     /*  14 */ "Expire",
+     /*  15 */ "AutoCommit",
+     /*  16 */ "Not",
+     /*  17 */ "IntegrityCk",
+     /*  18 */ "Sort",
+     /*  19 */ "Copy",
+     /*  20 */ "Trace",
+     /*  21 */ "Function",
+     /*  22 */ "IfNeg",
+     /*  23 */ "Noop",
+     /*  24 */ "Return",
+     /*  25 */ "NewRowid",
+     /*  26 */ "Variable",
+     /*  27 */ "String",
+     /*  28 */ "RealAffinity",
+     /*  29 */ "VRename",
+     /*  30 */ "ParseSchema",
+     /*  31 */ "VOpen",
+     /*  32 */ "Close",
+     /*  33 */ "CreateIndex",
+     /*  34 */ "IsUnique",
+     /*  35 */ "NotFound",
+     /*  36 */ "Int64",
+     /*  37 */ "MustBeInt",
+     /*  38 */ "Halt",
+     /*  39 */ "Rowid",
+     /*  40 */ "IdxLT",
+     /*  41 */ "AddImm",
+     /*  42 */ "Statement",
+     /*  43 */ "RowData",
+     /*  44 */ "MemMax",
+     /*  45 */ "NotExists",
+     /*  46 */ "Gosub",
+     /*  47 */ "Integer",
+     /*  48 */ "Prev",
+     /*  49 */ "VColumn",
+     /*  50 */ "CreateTable",
+     /*  51 */ "Last",
+     /*  52 */ "IncrVacuum",
+     /*  53 */ "IdxRowid",
+     /*  54 */ "ResetCount",
+     /*  55 */ "FifoWrite",
+     /*  56 */ "ContextPush",
+     /*  57 */ "DropTrigger",
+     /*  58 */ "DropIndex",
+     /*  59 */ "IdxGE",
+     /*  60 */ "Or",
+     /*  61 */ "And",
+     /*  62 */ "IdxDelete",
+     /*  63 */ "Vacuum",
+     /*  64 */ "MoveLe",
+     /*  65 */ "IsNull",
+     /*  66 */ "NotNull",
+     /*  67 */ "Ne",
+     /*  68 */ "Eq",
+     /*  69 */ "Gt",
+     /*  70 */ "Le",
+     /*  71 */ "Lt",
+     /*  72 */ "Ge",
+     /*  73 */ "IfNot",
+     /*  74 */ "BitAnd",
+     /*  75 */ "BitOr",
+     /*  76 */ "ShiftLeft",
+     /*  77 */ "ShiftRight",
+     /*  78 */ "Add",
+     /*  79 */ "Subtract",
+     /*  80 */ "Multiply",
+     /*  81 */ "Divide",
+     /*  82 */ "Remainder",
+     /*  83 */ "Concat",
+     /*  84 */ "DropTable",
+     /*  85 */ "MakeRecord",
+     /*  86 */ "ResultRow",
+     /*  87 */ "BitNot",
+     /*  88 */ "String8",
+     /*  89 */ "Delete",
+     /*  90 */ "AggFinal",
+     /*  91 */ "Goto",
+     /*  92 */ "TableLock",
+     /*  93 */ "FifoRead",
+     /*  94 */ "Clear",
+     /*  95 */ "MoveLt",
+     /*  96 */ "VerifyCookie",
+     /*  97 */ "AggStep",
+     /*  98 */ "SetNumColumns",
+     /*  99 */ "Transaction",
+     /* 100 */ "VFilter",
+     /* 101 */ "VDestroy",
+     /* 102 */ "ContextPop",
+     /* 103 */ "Next",
+     /* 104 */ "IdxInsert",
+     /* 105 */ "Insert",
+     /* 106 */ "Destroy",
+     /* 107 */ "ReadCookie",
+     /* 108 */ "ForceInt",
+     /* 109 */ "LoadAnalysis",
+     /* 110 */ "Explain",
+     /* 111 */ "OpenPseudo",
+     /* 112 */ "OpenEphemeral",
+     /* 113 */ "Null",
+     /* 114 */ "Move",
+     /* 115 */ "Blob",
+     /* 116 */ "Rewind",
+     /* 117 */ "MoveGe",
+     /* 118 */ "VBegin",
+     /* 119 */ "VUpdate",
+     /* 120 */ "IfZero",
+     /* 121 */ "VCreate",
+     /* 122 */ "Found",
+     /* 123 */ "IfPos",
+     /* 124 */ "NullRow",
+     /* 125 */ "Real",
+     /* 126 */ "NotUsed_126",
+     /* 127 */ "NotUsed_127",
+     /* 128 */ "NotUsed_128",
+     /* 129 */ "NotUsed_129",
+     /* 130 */ "NotUsed_130",
+     /* 131 */ "NotUsed_131",
+     /* 132 */ "NotUsed_132",
+     /* 133 */ "NotUsed_133",
+     /* 134 */ "NotUsed_134",
+     /* 135 */ "NotUsed_135",
+     /* 136 */ "NotUsed_136",
+     /* 137 */ "NotUsed_137",
+     /* 138 */ "ToText",
+     /* 139 */ "ToBlob",
+     /* 140 */ "ToNumeric",
+     /* 141 */ "ToInt",
+     /* 142 */ "ToReal",
+  };
+  return azName[i];
+}
+#endif
+
+/************** End of opcodes.c *********************************************/
+/************** Begin file os_os2.c ******************************************/
+/*
+** 2006 Feb 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to OS/2.
+*/
+
+
+#if OS_OS2
+
+/*
+** A Note About Memory Allocation:
+**
+** This driver uses malloc()/free() directly rather than going through
+** the SQLite-wrappers sqlite3_malloc()/sqlite3_free().  Those wrappers
+** are designed for use on embedded systems where memory is scarce and
+** malloc failures happen frequently.  OS/2 does not typically run on
+** embedded systems, and when it does the developers normally have bigger
+** problems to worry about than running out of memory.  So there is not
+** a compelling need to use the wrappers.
+**
+** But there is a good reason to not use the wrappers.  If we use the
+** wrappers then we will get simulated malloc() failures within this
+** driver.  And that causes all kinds of problems for our tests.  We
+** could enhance SQLite to deal with simulated malloc failures within
+** the OS driver, but the code to deal with those failure would not
+** be exercised on Linux (which does not need to malloc() in the driver)
+** and so we would have difficulty writing coverage tests for that
+** code.  Better to leave the code out, we think.
+**
+** The point of this discussion is as follows:  When creating a new
+** OS layer for an embedded system, if you use this file as an example,
+** avoid the use of malloc()/free().  Those routines work ok on OS/2
+** desktops but not so well in embedded systems.
+*/
+
+/*
+** Macros used to determine whether or not to use threads.
+*/
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE
+# define SQLITE_OS2_THREADS 1
+#endif
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/************** Include os_common.h in the middle of os_os2.c ****************/
+/************** Begin file os_common.h ***************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains macros and a little bit of code that is common to
+** all of the platform-specific files (os_*.c) and is #included into those
+** files.
+**
+** This file should be #included by the os_*.c files only.  It is not a
+** general purpose header file.
+*/
+
+/*
+** At least two bugs have slipped in because we changed the MEMORY_DEBUG
+** macro to SQLITE_DEBUG and some older makefiles have not yet made the
+** switch.  The following code should catch this problem at compile-time.
+*/
+#ifdef MEMORY_DEBUG
+# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
+#endif
+
+
+/*
+ * When testing, this global variable stores the location of the
+ * pending-byte in the database file.
+ */
+#ifdef SQLITE_TEST
+SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3OSTrace = 0;
+#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
+#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
+#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
+#else
+#define OSTRACE1(X)
+#define OSTRACE2(X,Y)
+#define OSTRACE3(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D)
+#endif
+
+/*
+** Macros for performance tracing.  Normally turned off.  Only works
+** on i486 hardware.
+*/
+#ifdef SQLITE_PERFORMANCE_TRACE
+__inline__ unsigned long long int hwtime(void){
+  unsigned long long int x;
+  __asm__("rdtsc\n\t"
+          "mov %%edx, %%ecx\n\t"
+          :"=A" (x));
+  return x;
+}
+static unsigned long long int g_start;
+static unsigned int elapse;
+#define TIMER_START       g_start=hwtime()
+#define TIMER_END         elapse=hwtime()-g_start
+#define TIMER_ELAPSED     elapse
+#else
+#define TIMER_START
+#define TIMER_END
+#define TIMER_ELAPSED     0
+#endif
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
+SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
+SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
+SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
+SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
+SQLITE_API int sqlite3_diskfull_pending = 0;
+SQLITE_API int sqlite3_diskfull = 0;
+#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
+#define SimulateIOError(CODE)  \
+  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
+       || sqlite3_io_error_pending-- == 1 )  \
+              { local_ioerr(); CODE; }
+static void local_ioerr(){
+  IOTRACE(("IOERR\n"));
+  sqlite3_io_error_hit++;
+  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
+}
+#define SimulateDiskfullError(CODE) \
+   if( sqlite3_diskfull_pending ){ \
+     if( sqlite3_diskfull_pending == 1 ){ \
+       local_ioerr(); \
+       sqlite3_diskfull = 1; \
+       sqlite3_io_error_hit = 1; \
+       CODE; \
+     }else{ \
+       sqlite3_diskfull_pending--; \
+     } \
+   }
+#else
+#define SimulateIOErrorBenign(X)
+#define SimulateIOError(A)
+#define SimulateDiskfullError(A)
+#endif
+
+/*
+** When testing, keep a count of the number of open files.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_open_file_count = 0;
+#define OpenCounter(X)  sqlite3_open_file_count+=(X)
+#else
+#define OpenCounter(X)
+#endif
+
+/************** End of os_common.h *******************************************/
+/************** Continuing where we left off in os_os2.c *********************/
+
+/*
+** The os2File structure is subclass of sqlite3_file specific for the OS/2
+** protability layer.
+*/
+typedef struct os2File os2File;
+struct os2File {
+  const sqlite3_io_methods *pMethod;  /* Always the first entry */
+  HFILE h;                  /* Handle for accessing the file */
+  char* pathToDel;          /* Name of file to delete on close, NULL if not */
+  unsigned char locktype;   /* Type of lock currently held on this file */
+};
+
+#define LOCK_TIMEOUT 10L /* the default locking timeout */
+
+/*****************************************************************************
+** The next group of routines implement the I/O methods specified
+** by the sqlite3_io_methods object.
+******************************************************************************/
+
+/*
+** Close a file.
+*/
+int os2Close( sqlite3_file *id ){
+  APIRET rc = NO_ERROR;
+  os2File *pFile;
+  if( id && (pFile = (os2File*)id) != 0 ){
+    OSTRACE2( "CLOSE %d\n", pFile->h );
+    rc = DosClose( pFile->h );
+    pFile->locktype = NO_LOCK;
+    if( pFile->pathToDel != NULL ){
+      rc = DosForceDelete( (PSZ)pFile->pathToDel );
+      free( pFile->pathToDel );
+      pFile->pathToDel = NULL;
+    }
+    id = 0;
+    OpenCounter( -1 );
+  }
+
+  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+int os2Read(
+  sqlite3_file *id,               /* File to read from */
+  void *pBuf,                     /* Write content into this buffer */
+  int amt,                        /* Number of bytes to read */
+  sqlite3_int64 offset            /* Begin reading at this offset */
+){
+  ULONG fileLocation = 0L;
+  ULONG got;
+  os2File *pFile = (os2File*)id;
+  assert( id!=0 );
+  SimulateIOError( return SQLITE_IOERR_READ );
+  OSTRACE3( "READ %d lock=%d\n", pFile->h, pFile->locktype );
+  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
+    return SQLITE_IOERR;
+  }
+  if( DosRead( pFile->h, pBuf, amt, &got ) != NO_ERROR ){
+    return SQLITE_IOERR_READ;
+  }
+  if( got == (ULONG)amt )
+    return SQLITE_OK;
+  else {
+    memset(&((char*)pBuf)[got], 0, amt-got);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+}
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+int os2Write(
+  sqlite3_file *id,               /* File to write into */
+  const void *pBuf,               /* The bytes to be written */
+  int amt,                        /* Number of bytes to write */
+  sqlite3_int64 offset            /* Offset into the file to begin writing at */
+){
+  ULONG fileLocation = 0L;
+  APIRET rc = NO_ERROR;
+  ULONG wrote;
+  os2File *pFile = (os2File*)id;
+  assert( id!=0 );
+  SimulateIOError( return SQLITE_IOERR_WRITE );
+  SimulateDiskfullError( return SQLITE_FULL );
+  OSTRACE3( "WRITE %d lock=%d\n", pFile->h, pFile->locktype );
+  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
+    return SQLITE_IOERR;
+  }
+  assert( amt>0 );
+  while( amt > 0 &&
+         ( rc = DosWrite( pFile->h, (PVOID)pBuf, amt, &wrote ) ) == NO_ERROR &&
+         wrote > 0
+  ){
+    amt -= wrote;
+    pBuf = &((char*)pBuf)[wrote];
+  }
+
+  return ( rc != NO_ERROR || amt > (int)wrote ) ? SQLITE_FULL : SQLITE_OK;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+int os2Truncate( sqlite3_file *id, i64 nByte ){
+  APIRET rc = NO_ERROR;
+  os2File *pFile = (os2File*)id;
+  OSTRACE3( "TRUNCATE %d %lld\n", pFile->h, nByte );
+  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
+  rc = DosSetFileSize( pFile->h, nByte );
+  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occuring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+*/
+int os2Sync( sqlite3_file *id, int flags ){
+  os2File *pFile = (os2File*)id;
+  OSTRACE3( "SYNC %d lock=%d\n", pFile->h, pFile->locktype );
+#ifdef SQLITE_TEST
+  if( flags & SQLITE_SYNC_FULL){
+    sqlite3_fullsync_count++;
+  }
+  sqlite3_sync_count++;
+#endif
+  return DosResetBuffer( pFile->h ) == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+int os2FileSize( sqlite3_file *id, sqlite3_int64 *pSize ){
+  APIRET rc = NO_ERROR;
+  FILESTATUS3 fsts3FileInfo;
+  memset(&fsts3FileInfo, 0, sizeof(fsts3FileInfo));
+  assert( id!=0 );
+  SimulateIOError( return SQLITE_IOERR );
+  rc = DosQueryFileInfo( ((os2File*)id)->h, FIL_STANDARD, &fsts3FileInfo, sizeof(FILESTATUS3) );
+  if( rc == NO_ERROR ){
+    *pSize = fsts3FileInfo.cbFile;
+    return SQLITE_OK;
+  }else{
+    return SQLITE_IOERR;
+  }
+}
+
+/*
+** Acquire a reader lock.
+*/
+static int getReadLock( os2File *pFile ){
+  FILELOCK  LockArea,
+            UnlockArea;
+  APIRET res;
+  memset(&LockArea, 0, sizeof(LockArea));
+  memset(&UnlockArea, 0, sizeof(UnlockArea));
+  LockArea.lOffset = SHARED_FIRST;
+  LockArea.lRange = SHARED_SIZE;
+  UnlockArea.lOffset = 0L;
+  UnlockArea.lRange = 0L;
+  res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
+  OSTRACE3( "GETREADLOCK %d res=%d\n", pFile->h, res );
+  return res;
+}
+
+/*
+** Undo a readlock
+*/
+static int unlockReadLock( os2File *id ){
+  FILELOCK  LockArea,
+            UnlockArea;
+  APIRET res;
+  memset(&LockArea, 0, sizeof(LockArea));
+  memset(&UnlockArea, 0, sizeof(UnlockArea));
+  LockArea.lOffset = 0L;
+  LockArea.lRange = 0L;
+  UnlockArea.lOffset = SHARED_FIRST;
+  UnlockArea.lRange = SHARED_SIZE;
+  res = DosSetFileLocks( id->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
+  OSTRACE3( "UNLOCK-READLOCK file handle=%d res=%d?\n", id->h, res );
+  return res;
+}
+
+/*
+** Lock the file with the lock specified by parameter locktype - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  The os2Unlock() routine
+** erases all locks at once and returns us immediately to locking level 0.
+** It is not possible to lower the locking level one step at a time.  You
+** must go straight to locking level 0.
+*/
+int os2Lock( sqlite3_file *id, int locktype ){
+  int rc = SQLITE_OK;       /* Return code from subroutines */
+  APIRET res = NO_ERROR;    /* Result of an OS/2 lock call */
+  int newLocktype;       /* Set pFile->locktype to this value before exiting */
+  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
+  FILELOCK  LockArea,
+            UnlockArea;
+  os2File *pFile = (os2File*)id;
+  memset(&LockArea, 0, sizeof(LockArea));
+  memset(&UnlockArea, 0, sizeof(UnlockArea));
+  assert( pFile!=0 );
+  OSTRACE4( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype );
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** os2File, do nothing. Don't use the end_lock: exit path, as
+  ** sqlite3_mutex_enter() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    OSTRACE3( "LOCK %d %d ok (already held)\n", pFile->h, locktype );
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
+  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
+  ** the PENDING_LOCK byte is temporary.
+  */
+  newLocktype = pFile->locktype;
+  if( pFile->locktype==NO_LOCK
+      || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
+  ){
+    LockArea.lOffset = PENDING_BYTE;
+    LockArea.lRange = 1L;
+    UnlockArea.lOffset = 0L;
+    UnlockArea.lRange = 0L;
+
+    /* wait longer than LOCK_TIMEOUT here not to have to try multiple times */
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 100L, 0L );
+    if( res == NO_ERROR ){
+      gotPendingLock = 1;
+      OSTRACE3( "LOCK %d pending lock boolean set.  res=%d\n", pFile->h, res );
+    }
+  }
+
+  /* Acquire a shared lock
+  */
+  if( locktype==SHARED_LOCK && res == NO_ERROR ){
+    assert( pFile->locktype==NO_LOCK );
+    res = getReadLock(pFile);
+    if( res == NO_ERROR ){
+      newLocktype = SHARED_LOCK;
+    }
+    OSTRACE3( "LOCK %d acquire shared lock. res=%d\n", pFile->h, res );
+  }
+
+  /* Acquire a RESERVED lock
+  */
+  if( locktype==RESERVED_LOCK && res == NO_ERROR ){
+    assert( pFile->locktype==SHARED_LOCK );
+    LockArea.lOffset = RESERVED_BYTE;
+    LockArea.lRange = 1L;
+    UnlockArea.lOffset = 0L;
+    UnlockArea.lRange = 0L;
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    if( res == NO_ERROR ){
+      newLocktype = RESERVED_LOCK;
+    }
+    OSTRACE3( "LOCK %d acquire reserved lock. res=%d\n", pFile->h, res );
+  }
+
+  /* Acquire a PENDING lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
+    newLocktype = PENDING_LOCK;
+    gotPendingLock = 0;
+    OSTRACE2( "LOCK %d acquire pending lock. pending lock boolean unset.\n", pFile->h );
+  }
+
+  /* Acquire an EXCLUSIVE lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
+    assert( pFile->locktype>=SHARED_LOCK );
+    res = unlockReadLock(pFile);
+    OSTRACE2( "unreadlock = %d\n", res );
+    LockArea.lOffset = SHARED_FIRST;
+    LockArea.lRange = SHARED_SIZE;
+    UnlockArea.lOffset = 0L;
+    UnlockArea.lRange = 0L;
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    if( res == NO_ERROR ){
+      newLocktype = EXCLUSIVE_LOCK;
+    }else{
+      OSTRACE2( "OS/2 error-code = %d\n", res );
+      getReadLock(pFile);
+    }
+    OSTRACE3( "LOCK %d acquire exclusive lock.  res=%d\n", pFile->h, res );
+  }
+
+  /* If we are holding a PENDING lock that ought to be released, then
+  ** release it now.
+  */
+  if( gotPendingLock && locktype==SHARED_LOCK ){
+    int r;
+    LockArea.lOffset = 0L;
+    LockArea.lRange = 0L;
+    UnlockArea.lOffset = PENDING_BYTE;
+    UnlockArea.lRange = 1L;
+    r = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    OSTRACE3( "LOCK %d unlocking pending/is shared. r=%d\n", pFile->h, r );
+  }
+
+  /* Update the state of the lock has held in the file descriptor then
+  ** return the appropriate result code.
+  */
+  if( res == NO_ERROR ){
+    rc = SQLITE_OK;
+  }else{
+    OSTRACE4( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
+              locktype, newLocktype );
+    rc = SQLITE_BUSY;
+  }
+  pFile->locktype = newLocktype;
+  OSTRACE3( "LOCK %d now %d\n", pFile->h, pFile->locktype );
+  return rc;
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, return
+** non-zero, otherwise zero.
+*/
+int os2CheckReservedLock( sqlite3_file *id ){
+  int r = 0;
+  os2File *pFile = (os2File*)id;
+  assert( pFile!=0 );
+  if( pFile->locktype>=RESERVED_LOCK ){
+    r = 1;
+    OSTRACE3( "TEST WR-LOCK %d %d (local)\n", pFile->h, r );
+  }else{
+    FILELOCK  LockArea,
+              UnlockArea;
+    APIRET rc = NO_ERROR;
+    memset(&LockArea, 0, sizeof(LockArea));
+    memset(&UnlockArea, 0, sizeof(UnlockArea));
+    LockArea.lOffset = RESERVED_BYTE;
+    LockArea.lRange = 1L;
+    UnlockArea.lOffset = 0L;
+    UnlockArea.lRange = 0L;
+    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    OSTRACE3( "TEST WR-LOCK %d lock reserved byte rc=%d\n", pFile->h, rc );
+    if( rc == NO_ERROR ){
+      APIRET rcu = NO_ERROR; /* return code for unlocking */
+      LockArea.lOffset = 0L;
+      LockArea.lRange = 0L;
+      UnlockArea.lOffset = RESERVED_BYTE;
+      UnlockArea.lRange = 1L;
+      rcu = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+      OSTRACE3( "TEST WR-LOCK %d unlock reserved byte r=%d\n", pFile->h, rcu );
+    }
+    r = !(rc == NO_ERROR);
+    OSTRACE3( "TEST WR-LOCK %d %d (remote)\n", pFile->h, r );
+  }
+  return r;
+}
+
+/*
+** Lower the locking level on file descriptor id to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** It is not possible for this routine to fail if the second argument
+** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
+** might return SQLITE_IOERR;
+*/
+int os2Unlock( sqlite3_file *id, int locktype ){
+  int type;
+  os2File *pFile = (os2File*)id;
+  APIRET rc = SQLITE_OK;
+  APIRET res = NO_ERROR;
+  FILELOCK  LockArea,
+            UnlockArea;
+  memset(&LockArea, 0, sizeof(LockArea));
+  memset(&UnlockArea, 0, sizeof(UnlockArea));
+  assert( pFile!=0 );
+  assert( locktype<=SHARED_LOCK );
+  OSTRACE4( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype );
+  type = pFile->locktype;
+  if( type>=EXCLUSIVE_LOCK ){
+    LockArea.lOffset = 0L;
+    LockArea.lRange = 0L;
+    UnlockArea.lOffset = SHARED_FIRST;
+    UnlockArea.lRange = SHARED_SIZE;
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    OSTRACE3( "UNLOCK %d exclusive lock res=%d\n", pFile->h, res );
+    if( locktype==SHARED_LOCK && getReadLock(pFile) != NO_ERROR ){
+      /* This should never happen.  We should always be able to
+      ** reacquire the read lock */
+      OSTRACE3( "UNLOCK %d to %d getReadLock() failed\n", pFile->h, locktype );
+      rc = SQLITE_IOERR_UNLOCK;
+    }
+  }
+  if( type>=RESERVED_LOCK ){
+    LockArea.lOffset = 0L;
+    LockArea.lRange = 0L;
+    UnlockArea.lOffset = RESERVED_BYTE;
+    UnlockArea.lRange = 1L;
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    OSTRACE3( "UNLOCK %d reserved res=%d\n", pFile->h, res );
+  }
+  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
+    res = unlockReadLock(pFile);
+    OSTRACE5( "UNLOCK %d is %d want %d res=%d\n", pFile->h, type, locktype, res );
+  }
+  if( type>=PENDING_LOCK ){
+    LockArea.lOffset = 0L;
+    LockArea.lRange = 0L;
+    UnlockArea.lOffset = PENDING_BYTE;
+    UnlockArea.lRange = 1L;
+    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
+    OSTRACE3( "UNLOCK %d pending res=%d\n", pFile->h, res );
+  }
+  pFile->locktype = locktype;
+  OSTRACE3( "UNLOCK %d now %d\n", pFile->h, pFile->locktype );
+  return rc;
+}
+
+/*
+** Control and query of the open file handle.
+*/
+static int os2FileControl(sqlite3_file *id, int op, void *pArg){
+  switch( op ){
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = ((os2File*)id)->locktype;
+      OSTRACE3( "FCNTL_LOCKSTATE %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int os2SectorSize(sqlite3_file *id){
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+/*
+** Return a vector of device characteristics.
+*/
+static int os2DeviceCharacteristics(sqlite3_file *id){
+  return 0;
+}
+
+/*
+** Helper function to convert UTF-8 filenames to local OS/2 codepage.
+** The two-step process: first convert the incoming UTF-8 string
+** into UCS-2 and then from UCS-2 to the current codepage.
+** The returned char pointer has to be freed.
+*/
+char *convertUtf8PathToCp(const char *in)
+{
+  UconvObject uconv;
+  UniChar ucsUtf8Cp[12],
+          tempPath[CCHMAXPATH];
+  char *out;
+  int rc = 0;
+
+  out = (char *)calloc(CCHMAXPATH, 1);
+
+  /* determine string for the conversion of UTF-8 which is CP1208 */
+  rc = UniMapCpToUcsCp(1208, ucsUtf8Cp, 12);
+  rc = UniCreateUconvObject(ucsUtf8Cp, &uconv);
+  rc = UniStrToUcs(uconv, tempPath, (char *)in, CCHMAXPATH);
+  rc = UniFreeUconvObject(uconv);
+
+  /* conversion for current codepage which can be used for paths */
+  rc = UniCreateUconvObject((UniChar *)L"@path=yes", &uconv);
+  rc = UniStrFromUcs(uconv, out, tempPath, CCHMAXPATH);
+  rc = UniFreeUconvObject(uconv);
+
+  return out;
+}
+
+/*
+** Helper function to convert filenames from local codepage to UTF-8.
+** The two-step process: first convert the incoming codepage-specific
+** string into UCS-2 and then from UCS-2 to the codepage of UTF-8.
+** The returned char pointer has to be freed.
+*/
+char *convertCpPathToUtf8(const char *in)
+{
+  UconvObject uconv;
+  UniChar ucsUtf8Cp[12],
+          tempPath[CCHMAXPATH];
+  char *out;
+  int rc = 0;
+
+  out = (char *)calloc(CCHMAXPATH, 1);
+
+  /* conversion for current codepage which can be used for paths */
+  rc = UniCreateUconvObject((UniChar *)L"@path=yes", &uconv);
+  rc = UniStrToUcs(uconv, tempPath, (char *)in, CCHMAXPATH);
+  rc = UniFreeUconvObject(uconv);
+
+  /* determine string for the conversion of UTF-8 which is CP1208 */
+  rc = UniMapCpToUcsCp(1208, ucsUtf8Cp, 12);
+  rc = UniCreateUconvObject(ucsUtf8Cp, &uconv);
+  rc = UniStrFromUcs(uconv, out, tempPath, CCHMAXPATH);
+  rc = UniFreeUconvObject(uconv);
+
+  return out;
+}
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for os2.
+*/
+static const sqlite3_io_methods os2IoMethod = {
+  1,                        /* iVersion */
+  os2Close,
+  os2Read,
+  os2Write,
+  os2Truncate,
+  os2Sync,
+  os2FileSize,
+  os2Lock,
+  os2Unlock,
+  os2CheckReservedLock,
+  os2FileControl,
+  os2SectorSize,
+  os2DeviceCharacteristics
+};
+
+/***************************************************************************
+** Here ends the I/O methods that form the sqlite3_io_methods object.
+**
+** The next block of code implements the VFS methods.
+****************************************************************************/
+
+/*
+** Open a file.
+*/
+static int os2Open(
+  sqlite3_vfs *pVfs,            /* Not used */
+  const char *zName,            /* Name of the file */
+  sqlite3_file *id,             /* Write the SQLite file handle here */
+  int flags,                    /* Open mode flags */
+  int *pOutFlags                /* Status return flags */
+){
+  HFILE h;
+  ULONG ulFileAttribute = 0;
+  ULONG ulOpenFlags = 0;
+  ULONG ulOpenMode = 0;
+  os2File *pFile = (os2File*)id;
+  APIRET rc = NO_ERROR;
+  ULONG ulAction;
+
+  memset( pFile, 0, sizeof(*pFile) );
+
+  OSTRACE2( "OPEN want %d\n", flags );
+
+  /*ulOpenMode = flags & SQLITE_OPEN_READWRITE ? OPEN_ACCESS_READWRITE : OPEN_ACCESS_READONLY;*/
+  if( flags & SQLITE_OPEN_READWRITE ){
+    ulOpenMode |= OPEN_ACCESS_READWRITE;
+    OSTRACE1( "OPEN read/write\n" );
+  }else{
+    ulOpenMode |= OPEN_ACCESS_READONLY;
+    OSTRACE1( "OPEN read only\n" );
+  }
+
+  /*ulOpenFlags = flags & SQLITE_OPEN_CREATE ? OPEN_ACTION_CREATE_IF_NEW : OPEN_ACTION_FAIL_IF_NEW;*/
+  if( flags & SQLITE_OPEN_CREATE ){
+    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_CREATE_IF_NEW;
+    OSTRACE1( "OPEN open new/create\n" );
+  }else{
+    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_FAIL_IF_NEW;
+    OSTRACE1( "OPEN open existing\n" );
+  }
+
+  /*ulOpenMode |= flags & SQLITE_OPEN_MAIN_DB ? OPEN_SHARE_DENYNONE : OPEN_SHARE_DENYWRITE;*/
+  if( flags & SQLITE_OPEN_MAIN_DB ){
+    ulOpenMode |= OPEN_SHARE_DENYNONE;
+    OSTRACE1( "OPEN share read/write\n" );
+  }else{
+    ulOpenMode |= OPEN_SHARE_DENYWRITE;
+    OSTRACE1( "OPEN share read only\n" );
+  }
+
+  if( flags & (SQLITE_OPEN_TEMP_DB | SQLITE_OPEN_TEMP_JOURNAL
+               | SQLITE_OPEN_SUBJOURNAL) ){
+    char pathUtf8[CCHMAXPATH];
+    /*ulFileAttribute = FILE_HIDDEN;  //for debugging, we want to make sure it is deleted*/
+    ulFileAttribute = FILE_NORMAL;
+    sqlite3OsFullPathname( pVfs, zName, CCHMAXPATH, pathUtf8 );
+    pFile->pathToDel = convertUtf8PathToCp( pathUtf8 );
+    OSTRACE1( "OPEN hidden/delete on close file attributes\n" );
+  }else{
+    ulFileAttribute = FILE_ARCHIVED | FILE_NORMAL;
+    pFile->pathToDel = NULL;
+    OSTRACE1( "OPEN normal file attribute\n" );
+  }
+
+  /* always open in random access mode for possibly better speed */
+  ulOpenMode |= OPEN_FLAGS_RANDOM;
+  ulOpenMode |= OPEN_FLAGS_FAIL_ON_ERROR;
+  ulOpenMode |= OPEN_FLAGS_NOINHERIT;
+
+  char *zNameCp = convertUtf8PathToCp( zName );
+  rc = DosOpen( (PSZ)zNameCp,
+                &h,
+                &ulAction,
+                0L,
+                ulFileAttribute,
+                ulOpenFlags,
+                ulOpenMode,
+                (PEAOP2)NULL );
+  free( zNameCp );
+  if( rc != NO_ERROR ){
+    OSTRACE7( "OPEN Invalid handle rc=%d: zName=%s, ulAction=%#lx, ulAttr=%#lx, ulFlags=%#lx, ulMode=%#lx\n",
+              rc, zName, ulAction, ulFileAttribute, ulOpenFlags, ulOpenMode );
+    free( pFile->pathToDel );
+    pFile->pathToDel = NULL;
+    if( flags & SQLITE_OPEN_READWRITE ){
+      OSTRACE2( "OPEN %d Invalid handle\n", ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE) );
+      return os2Open( 0, zName, id,
+                      ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE),
+                      pOutFlags );
+    }else{
+      return SQLITE_CANTOPEN;
+    }
+  }
+
+  if( pOutFlags ){
+    *pOutFlags = flags & SQLITE_OPEN_READWRITE ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY;
+  }
+
+  pFile->pMethod = &os2IoMethod;
+  pFile->h = h;
+  OpenCounter(+1);
+  OSTRACE3( "OPEN %d pOutFlags=%d\n", pFile->h, pOutFlags );
+  return SQLITE_OK;
+}
+
+/*
+** Delete the named file.
+*/
+int os2Delete(
+  sqlite3_vfs *pVfs,                     /* Not used on os2 */
+  const char *zFilename,                 /* Name of file to delete */
+  int syncDir                            /* Not used on os2 */
+){
+  APIRET rc = NO_ERROR;
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  char *zFilenameCp = convertUtf8PathToCp( zFilename );
+  rc = DosDelete( (PSZ)zFilenameCp );
+  free( zFilenameCp );
+  OSTRACE2( "DELETE \"%s\"\n", zFilename );
+  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
+}
+
+/*
+** Check the existance and status of a file.
+*/
+static int os2Access(
+  sqlite3_vfs *pVfs,        /* Not used on os2 */
+  const char *zFilename,    /* Name of file to check */
+  int flags                 /* Type of test to make on this file */
+){
+  FILESTATUS3 fsts3ConfigInfo;
+  APIRET rc = NO_ERROR;
+
+  memset( &fsts3ConfigInfo, 0, sizeof(fsts3ConfigInfo) );
+  char *zFilenameCp = convertUtf8PathToCp( zFilename );
+  rc = DosQueryPathInfo( (PSZ)zFilenameCp, FIL_STANDARD,
+                         &fsts3ConfigInfo, sizeof(FILESTATUS3) );
+  free( zFilenameCp );
+  OSTRACE4( "ACCESS fsts3ConfigInfo.attrFile=%d flags=%d rc=%d\n",
+            fsts3ConfigInfo.attrFile, flags, rc );
+  switch( flags ){
+    case SQLITE_ACCESS_READ:
+    case SQLITE_ACCESS_EXISTS:
+      rc = (rc == NO_ERROR);
+      OSTRACE3( "ACCESS %s access of read and exists  rc=%d\n", zFilename, rc );
+      break;
+    case SQLITE_ACCESS_READWRITE:
+      rc = (fsts3ConfigInfo.attrFile & FILE_READONLY) == 0;
+      OSTRACE3( "ACCESS %s access of read/write  rc=%d\n", zFilename, rc );
+      break;
+    default:
+      assert( !"Invalid flags argument" );
+  }
+  return rc;
+}
+
+
+/*
+** Create a temporary file name in zBuf.  zBuf must be big enough to
+** hold at pVfs->mxPathname characters.
+*/
+static int os2GetTempname( sqlite3_vfs *pVfs, int nBuf, char *zBuf ){
+  static const unsigned char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  int i, j;
+  char zTempPathBuf[3];
+  PSZ zTempPath = (PSZ)&zTempPathBuf;
+  char *zTempPathUTF;
+  if( DosScanEnv( (PSZ)"TEMP", &zTempPath ) ){
+    if( DosScanEnv( (PSZ)"TMP", &zTempPath ) ){
+      if( DosScanEnv( (PSZ)"TMPDIR", &zTempPath ) ){
+           ULONG ulDriveNum = 0, ulDriveMap = 0;
+           DosQueryCurrentDisk( &ulDriveNum, &ulDriveMap );
+           sprintf( (char*)zTempPath, "%c:", (char)( 'A' + ulDriveNum - 1 ) );
+      }
+    }
+  }
+  /* strip off a trailing slashes or backslashes, otherwise we would get *
+   * multiple (back)slashes which causes DosOpen() to fail               */
+  j = strlen(zTempPath);
+  while( j > 0 && ( zTempPath[j-1] == '\\' || zTempPath[j-1] == '/' ) ){
+    j--;
+  }
+  zTempPath[j] = '\0';
+  zTempPathUTF = convertCpPathToUtf8( zTempPath );
+  sqlite3_snprintf( nBuf-30, zBuf,
+                    "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPathUTF );
+  free( zTempPathUTF );
+  j = strlen( zBuf );
+  sqlite3_randomness( 20, &zBuf[j] );
+  for( i = 0; i < 20; i++, j++ ){
+    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
+  }
+  zBuf[j] = 0;
+  OSTRACE2( "TEMP FILENAME: %s\n", zBuf );
+  return SQLITE_OK;
+}
+
+
+/*
+** Turn a relative pathname into a full pathname.  Write the full
+** pathname into zFull[].  zFull[] will be at least pVfs->mxPathname
+** bytes in size.
+*/
+static int os2FullPathname(
+  sqlite3_vfs *pVfs,          /* Pointer to vfs object */
+  const char *zRelative,      /* Possibly relative input path */
+  int nFull,                  /* Size of output buffer in bytes */
+  char *zFull                 /* Output buffer */
+){
+  char *zRelativeCp = convertUtf8PathToCp( zRelative );
+  char zFullCp[CCHMAXPATH];
+  char *zFullUTF;
+  APIRET rc = DosQueryPathInfo( zRelativeCp, FIL_QUERYFULLNAME, zFullCp,
+                                CCHMAXPATH );
+  free( zRelativeCp );
+  zFullUTF = convertCpPathToUtf8( zFullCp );
+  sqlite3_snprintf( nFull, zFull, zFullUTF );
+  free( zFullUTF );
+  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+static void *os2DlOpen(sqlite3_vfs *pVfs, const char *zFilename){
+  UCHAR loadErr[256];
+  HMODULE hmod;
+  APIRET rc;
+  char *zFilenameCp = convertUtf8PathToCp(zFilename);
+  rc = DosLoadModule((PSZ)loadErr, sizeof(loadErr), zFilenameCp, &hmod);
+  free(zFilenameCp);
+  return rc != NO_ERROR ? 0 : (void*)hmod;
+}
+/*
+** A no-op since the error code is returned on the DosLoadModule call.
+** os2Dlopen returns zero if DosLoadModule is not successful.
+*/
+static void os2DlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
+/* no-op */
+}
+void *os2DlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
+  PFN pfn;
+  APIRET rc;
+  rc = DosQueryProcAddr((HMODULE)pHandle, 0L, zSymbol, &pfn);
+  if( rc != NO_ERROR ){
+    /* if the symbol itself was not found, search again for the same
+     * symbol with an extra underscore, that might be needed depending
+     * on the calling convention */
+    char _zSymbol[256] = "_";
+    strncat(_zSymbol, zSymbol, 255);
+    rc = DosQueryProcAddr((HMODULE)pHandle, 0L, _zSymbol, &pfn);
+  }
+  return rc != NO_ERROR ? 0 : (void*)pfn;
+}
+void os2DlClose(sqlite3_vfs *pVfs, void *pHandle){
+  DosFreeModule((HMODULE)pHandle);
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define os2DlOpen 0
+  #define os2DlError 0
+  #define os2DlSym 0
+  #define os2DlClose 0
+#endif
+
+
+/*
+** Write up to nBuf bytes of randomness into zBuf.
+*/
+static int os2Randomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf ){
+  ULONG sizeofULong = sizeof(ULONG);
+  int n = 0;
+  if( sizeof(DATETIME) <= nBuf - n ){
+    DATETIME x;
+    DosGetDateTime(&x);
+    memcpy(&zBuf[n], &x, sizeof(x));
+    n += sizeof(x);
+  }
+
+  if( sizeofULong <= nBuf - n ){
+    PPIB ppib;
+    DosGetInfoBlocks(NULL, &ppib);
+    memcpy(&zBuf[n], &ppib->pib_ulpid, sizeofULong);
+    n += sizeofULong;
+  }
+
+  if( sizeofULong <= nBuf - n ){
+    PTIB ptib;
+    DosGetInfoBlocks(&ptib, NULL);
+    memcpy(&zBuf[n], &ptib->tib_ptib2->tib2_ultid, sizeofULong);
+    n += sizeofULong;
+  }
+
+  /* if we still haven't filled the buffer yet the following will */
+  /* grab everything once instead of making several calls for a single item */
+  if( sizeofULong <= nBuf - n ){
+    ULONG ulSysInfo[QSV_MAX];
+    DosQuerySysInfo(1L, QSV_MAX, ulSysInfo, sizeofULong * QSV_MAX);
+
+    memcpy(&zBuf[n], &ulSysInfo[QSV_MS_COUNT - 1], sizeofULong);
+    n += sizeofULong;
+
+    if( sizeofULong <= nBuf - n ){
+      memcpy(&zBuf[n], &ulSysInfo[QSV_TIMER_INTERVAL - 1], sizeofULong);
+      n += sizeofULong;
+    }
+    if( sizeofULong <= nBuf - n ){
+      memcpy(&zBuf[n], &ulSysInfo[QSV_TIME_LOW - 1], sizeofULong);
+      n += sizeofULong;
+    }
+    if( sizeofULong <= nBuf - n ){
+      memcpy(&zBuf[n], &ulSysInfo[QSV_TIME_HIGH - 1], sizeofULong);
+      n += sizeofULong;
+    }
+    if( sizeofULong <= nBuf - n ){
+      memcpy(&zBuf[n], &ulSysInfo[QSV_TOTAVAILMEM - 1], sizeofULong);
+      n += sizeofULong;
+    }
+  }
+
+  return n;
+}
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+** The argument is the number of microseconds we want to sleep.
+** The return value is the number of microseconds of sleep actually
+** requested from the underlying operating system, a number which
+** might be greater than or equal to the argument, but not less
+** than the argument.
+*/
+static int os2Sleep( sqlite3_vfs *pVfs, int microsec ){
+  DosSleep( (microsec/1000) );
+  return microsec;
+}
+
+/*
+** The following variable, if set to a non-zero value, becomes the result
+** returned from sqlite3OsCurrentTime().  This is used for testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+int os2CurrentTime( sqlite3_vfs *pVfs, double *prNow ){
+  double now;
+  SHORT minute; /* needs to be able to cope with negative timezone offset */
+  USHORT second, hour,
+         day, month, year;
+  DATETIME dt;
+  DosGetDateTime( &dt );
+  second = (USHORT)dt.seconds;
+  minute = (SHORT)dt.minutes + dt.timezone;
+  hour = (USHORT)dt.hours;
+  day = (USHORT)dt.day;
+  month = (USHORT)dt.month;
+  year = (USHORT)dt.year;
+
+  /* Calculations from http://www.astro.keele.ac.uk/~rno/Astronomy/hjd.html
+     http://www.astro.keele.ac.uk/~rno/Astronomy/hjd-0.1.c */
+  /* Calculate the Julian days */
+  now = day - 32076 +
+    1461*(year + 4800 + (month - 14)/12)/4 +
+    367*(month - 2 - (month - 14)/12*12)/12 -
+    3*((year + 4900 + (month - 14)/12)/100)/4;
+
+  /* Add the fractional hours, mins and seconds */
+  now += (hour + 12.0)/24.0;
+  now += minute/1440.0;
+  now += second/86400.0;
+  *prNow = now;
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
+  }
+#endif
+  return 0;
+}
+
+/*
+** Return a pointer to the sqlite3DefaultVfs structure.   We use
+** a function rather than give the structure global scope because
+** some compilers (MSVC) do not allow forward declarations of
+** initialized structures.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3OsDefaultVfs(void){
+  static sqlite3_vfs os2Vfs = {
+    1,                 /* iVersion */
+    sizeof(os2File),   /* szOsFile */
+    CCHMAXPATH,        /* mxPathname */
+    0,                 /* pNext */
+    "os2",             /* zName */
+    0,                 /* pAppData */
+
+    os2Open,           /* xOpen */
+    os2Delete,         /* xDelete */
+    os2Access,         /* xAccess */
+    os2GetTempname,    /* xGetTempname */
+    os2FullPathname,   /* xFullPathname */
+    os2DlOpen,         /* xDlOpen */
+    os2DlError,        /* xDlError */
+    os2DlSym,          /* xDlSym */
+    os2DlClose,        /* xDlClose */
+    os2Randomness,     /* xRandomness */
+    os2Sleep,          /* xSleep */
+    os2CurrentTime     /* xCurrentTime */
+  };
+
+  return &os2Vfs;
+}
+
+#endif /* OS_OS2 */
+
+/************** End of os_os2.c **********************************************/
+/************** Begin file os_unix.c *****************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Unix systems.
+*/
+#if OS_UNIX              /* This file is used on unix only */
+
+#include <qconfig.h>
+
+/* #define SQLITE_ENABLE_LOCKING_STYLE 0 */
+
+/*
+** These #defines should enable >2GB file support on Posix if the
+** underlying operating system supports it.  If the OS lacks
+** large file support, these should be no-ops.
+**
+** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
+** on the compiler command line.  This is necessary if you are compiling
+** on a recent machine (ex: RedHat 7.2) but you want your code to work
+** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2
+** without this option, LFS is enable.  But LFS does not exist in the kernel
+** in RedHat 6.0, so the code won't work.  Hence, for maximum binary
+** portability you should omit LFS.
+*/
+#ifndef SQLITE_DISABLE_LFS
+# define _LARGE_FILE       1
+# ifndef _FILE_OFFSET_BITS
+#   define _FILE_OFFSET_BITS 64
+# endif
+# define _LARGEFILE_SOURCE 1
+#endif
+
+/*
+** standard include files.
+*/
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <errno.h>
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/mount.h>
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** If we are to be thread-safe, include the pthreads header and define
+** the SQLITE_UNIX_THREADS macro.
+*/
+#ifndef QT_NO_THREAD
+# define SQLITE_UNIX_THREADS 1
+#endif
+
+/*
+** Default permissions when creating a new file
+*/
+#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS
+# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644
+#endif
+
+/*
+** Maximum supported path-length.
+*/
+#define MAX_PATHNAME 512
+
+
+/*
+** The unixFile structure is subclass of sqlite3_file specific for the unix
+** protability layer.
+*/
+typedef struct unixFile unixFile;
+struct unixFile {
+  sqlite3_io_methods const *pMethod;  /* Always the first entry */
+#ifdef SQLITE_TEST
+  /* In test mode, increase the size of this structure a bit so that 
+  ** it is larger than the struct CrashFile defined in test6.c.
+  */
+  char aPadding[32];
+#endif
+  struct openCnt *pOpen;    /* Info about all open fd's on this inode */
+  struct lockInfo *pLock;   /* Info about locks on this inode */
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+  void *lockingContext;     /* Locking style specific state */
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+  int h;                    /* The file descriptor */
+  unsigned char locktype;   /* The type of lock held on this fd */
+  int dirfd;                /* File descriptor for the directory */
+#if SQLITE_THREADSAFE
+  pthread_t tid;            /* The thread that "owns" this unixFile */
+#endif
+};
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/************** Include os_common.h in the middle of os_unix.c ***************/
+/************** Begin file os_common.h ***************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains macros and a little bit of code that is common to
+** all of the platform-specific files (os_*.c) and is #included into those
+** files.
+**
+** This file should be #included by the os_*.c files only.  It is not a
+** general purpose header file.
+*/
+
+/*
+** At least two bugs have slipped in because we changed the MEMORY_DEBUG
+** macro to SQLITE_DEBUG and some older makefiles have not yet made the
+** switch.  The following code should catch this problem at compile-time.
+*/
+#ifdef MEMORY_DEBUG
+# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
+#endif
+
+
+/*
+ * When testing, this global variable stores the location of the
+ * pending-byte in the database file.
+ */
+#ifdef SQLITE_TEST
+SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3OSTrace = 0;
+#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
+#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
+#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
+#else
+#define OSTRACE1(X)
+#define OSTRACE2(X,Y)
+#define OSTRACE3(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D)
+#endif
+
+/*
+** Macros for performance tracing.  Normally turned off.  Only works
+** on i486 hardware.
+*/
+#ifdef SQLITE_PERFORMANCE_TRACE
+__inline__ unsigned long long int hwtime(void){
+  unsigned long long int x;
+  __asm__("rdtsc\n\t"
+          "mov %%edx, %%ecx\n\t"
+          :"=A" (x));
+  return x;
+}
+static unsigned long long int g_start;
+static unsigned int elapse;
+#define TIMER_START       g_start=hwtime()
+#define TIMER_END         elapse=hwtime()-g_start
+#define TIMER_ELAPSED     elapse
+#else
+#define TIMER_START
+#define TIMER_END
+#define TIMER_ELAPSED     0
+#endif
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
+SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
+SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
+SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
+SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
+SQLITE_API int sqlite3_diskfull_pending = 0;
+SQLITE_API int sqlite3_diskfull = 0;
+#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
+#define SimulateIOError(CODE)  \
+  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
+       || sqlite3_io_error_pending-- == 1 )  \
+              { local_ioerr(); CODE; }
+static void local_ioerr(){
+  IOTRACE(("IOERR\n"));
+  sqlite3_io_error_hit++;
+  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
+}
+#define SimulateDiskfullError(CODE) \
+   if( sqlite3_diskfull_pending ){ \
+     if( sqlite3_diskfull_pending == 1 ){ \
+       local_ioerr(); \
+       sqlite3_diskfull = 1; \
+       sqlite3_io_error_hit = 1; \
+       CODE; \
+     }else{ \
+       sqlite3_diskfull_pending--; \
+     } \
+   }
+#else
+#define SimulateIOErrorBenign(X)
+#define SimulateIOError(A)
+#define SimulateDiskfullError(A)
+#endif
+
+/*
+** When testing, keep a count of the number of open files.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_open_file_count = 0;
+#define OpenCounter(X)  sqlite3_open_file_count+=(X)
+#else
+#define OpenCounter(X)
+#endif
+
+/************** End of os_common.h *******************************************/
+/************** Continuing where we left off in os_unix.c ********************/
+
+/*
+** Define various macros that are missing from some systems.
+*/
+#ifndef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifdef SQLITE_DISABLE_LFS
+# undef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifndef O_NOFOLLOW
+# define O_NOFOLLOW 0
+#endif
+#ifndef O_BINARY
+# define O_BINARY 0
+#endif
+
+/*
+** The DJGPP compiler environment looks mostly like Unix, but it
+** lacks the fcntl() system call.  So redefine fcntl() to be something
+** that always succeeds.  This means that locking does not occur under
+** DJGPP.  But it is DOS - what did you expect?
+*/
+#ifdef __DJGPP__
+# define fcntl(A,B,C) 0
+#endif
+
+/*
+** The threadid macro resolves to the thread-id or to 0.  Used for
+** testing and debugging only.
+*/
+#if SQLITE_THREADSAFE
+#define threadid pthread_self()
+#else
+#define threadid 0
+#endif
+
+/*
+** Set or check the unixFile.tid field.  This field is set when an unixFile
+** is first opened.  All subsequent uses of the unixFile verify that the
+** same thread is operating on the unixFile.  Some operating systems do
+** not allow locks to be overridden by other threads and that restriction
+** means that sqlite3* database handles cannot be moved from one thread
+** to another.  This logic makes sure a user does not try to do that
+** by mistake.
+**
+** Version 3.3.1 (2006-01-15):  unixFile can be moved from one thread to
+** another as long as we are running on a system that supports threads
+** overriding each others locks (which now the most common behavior)
+** or if no locks are held.  But the unixFile.pLock field needs to be
+** recomputed because its key includes the thread-id.  See the 
+** transferOwnership() function below for additional information
+*/
+#if SQLITE_THREADSAFE
+# define SET_THREADID(X)   (X)->tid = pthread_self()
+# define CHECK_THREADID(X) (threadsOverrideEachOthersLocks==0 && \
+                            !pthread_equal((X)->tid, pthread_self()))
+#else
+# define SET_THREADID(X)
+# define CHECK_THREADID(X) 0
+#endif
+
+/*
+** Here is the dirt on POSIX advisory locks:  ANSI STD 1003.1 (1996)
+** section 6.5.2.2 lines 483 through 490 specify that when a process
+** sets or clears a lock, that operation overrides any prior locks set
+** by the same process.  It does not explicitly say so, but this implies
+** that it overrides locks set by the same process using a different
+** file descriptor.  Consider this test case:
+**
+**       int fd1 = open("./file1", O_RDWR|O_CREAT, 0644);
+**       int fd2 = open("./file2", O_RDWR|O_CREAT, 0644);
+**
+** Suppose ./file1 and ./file2 are really the same file (because
+** one is a hard or symbolic link to the other) then if you set
+** an exclusive lock on fd1, then try to get an exclusive lock
+** on fd2, it works.  I would have expected the second lock to
+** fail since there was already a lock on the file due to fd1.
+** But not so.  Since both locks came from the same process, the
+** second overrides the first, even though they were on different
+** file descriptors opened on different file names.
+**
+** Bummer.  If you ask me, this is broken.  Badly broken.  It means
+** that we cannot use POSIX locks to synchronize file access among
+** competing threads of the same process.  POSIX locks will work fine
+** to synchronize access for threads in separate processes, but not
+** threads within the same process.
+**
+** To work around the problem, SQLite has to manage file locks internally
+** on its own.  Whenever a new database is opened, we have to find the
+** specific inode of the database file (the inode is determined by the
+** st_dev and st_ino fields of the stat structure that fstat() fills in)
+** and check for locks already existing on that inode.  When locks are
+** created or removed, we have to look at our own internal record of the
+** locks to see if another thread has previously set a lock on that same
+** inode.
+**
+** The sqlite3_file structure for POSIX is no longer just an integer file
+** descriptor.  It is now a structure that holds the integer file
+** descriptor and a pointer to a structure that describes the internal
+** locks on the corresponding inode.  There is one locking structure
+** per inode, so if the same inode is opened twice, both unixFile structures
+** point to the same locking structure.  The locking structure keeps
+** a reference count (so we will know when to delete it) and a "cnt"
+** field that tells us its internal lock status.  cnt==0 means the
+** file is unlocked.  cnt==-1 means the file has an exclusive lock.
+** cnt>0 means there are cnt shared locks on the file.
+**
+** Any attempt to lock or unlock a file first checks the locking
+** structure.  The fcntl() system call is only invoked to set a 
+** POSIX lock if the internal lock structure transitions between
+** a locked and an unlocked state.
+**
+** 2004-Jan-11:
+** More recent discoveries about POSIX advisory locks.  (The more
+** I discover, the more I realize the a POSIX advisory locks are
+** an abomination.)
+**
+** If you close a file descriptor that points to a file that has locks,
+** all locks on that file that are owned by the current process are
+** released.  To work around this problem, each unixFile structure contains
+** a pointer to an openCnt structure.  There is one openCnt structure
+** per open inode, which means that multiple unixFile can point to a single
+** openCnt.  When an attempt is made to close an unixFile, if there are
+** other unixFile open on the same inode that are holding locks, the call
+** to close() the file descriptor is deferred until all of the locks clear.
+** The openCnt structure keeps a list of file descriptors that need to
+** be closed and that list is walked (and cleared) when the last lock
+** clears.
+**
+** First, under Linux threads, because each thread has a separate
+** process ID, lock operations in one thread do not override locks
+** to the same file in other threads.  Linux threads behave like
+** separate processes in this respect.  But, if you close a file
+** descriptor in linux threads, all locks are cleared, even locks
+** on other threads and even though the other threads have different
+** process IDs.  Linux threads is inconsistent in this respect.
+** (I'm beginning to think that linux threads is an abomination too.)
+** The consequence of this all is that the hash table for the lockInfo
+** structure has to include the process id as part of its key because
+** locks in different threads are treated as distinct.  But the 
+** openCnt structure should not include the process id in its
+** key because close() clears lock on all threads, not just the current
+** thread.  Were it not for this goofiness in linux threads, we could
+** combine the lockInfo and openCnt structures into a single structure.
+**
+** 2004-Jun-28:
+** On some versions of linux, threads can override each others locks.
+** On others not.  Sometimes you can change the behavior on the same
+** system by setting the LD_ASSUME_KERNEL environment variable.  The
+** POSIX standard is silent as to which behavior is correct, as far
+** as I can tell, so other versions of unix might show the same
+** inconsistency.  There is no little doubt in my mind that posix
+** advisory locks and linux threads are profoundly broken.
+**
+** To work around the inconsistencies, we have to test at runtime 
+** whether or not threads can override each others locks.  This test
+** is run once, the first time any lock is attempted.  A static 
+** variable is set to record the results of this test for future
+** use.
+*/
+
+/*
+** An instance of the following structure serves as the key used
+** to locate a particular lockInfo structure given its inode.
+**
+** If threads cannot override each others locks, then we set the
+** lockKey.tid field to the thread ID.  If threads can override
+** each others locks then tid is always set to zero.  tid is omitted
+** if we compile without threading support.
+*/
+struct lockKey {
+  dev_t dev;       /* Device number */
+  ino_t ino;       /* Inode number */
+#if SQLITE_THREADSAFE
+  pthread_t tid;   /* Thread ID or zero if threads can override each other */
+#endif
+};
+
+/*
+** An instance of the following structure is allocated for each open
+** inode on each thread with a different process ID.  (Threads have
+** different process IDs on linux, but not on most other unixes.)
+**
+** A single inode can have multiple file descriptors, so each unixFile
+** structure contains a pointer to an instance of this object and this
+** object keeps a count of the number of unixFile pointing to it.
+*/
+struct lockInfo {
+  struct lockKey key;  /* The lookup key */
+  int cnt;             /* Number of SHARED locks held */
+  int locktype;        /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+  int nRef;            /* Number of pointers to this structure */
+};
+
+/*
+** An instance of the following structure serves as the key used
+** to locate a particular openCnt structure given its inode.  This
+** is the same as the lockKey except that the thread ID is omitted.
+*/
+struct openKey {
+  dev_t dev;   /* Device number */
+  ino_t ino;   /* Inode number */
+};
+
+/*
+** An instance of the following structure is allocated for each open
+** inode.  This structure keeps track of the number of locks on that
+** inode.  If a close is attempted against an inode that is holding
+** locks, the close is deferred until all locks clear by adding the
+** file descriptor to be closed to the pending list.
+*/
+struct openCnt {
+  struct openKey key;   /* The lookup key */
+  int nRef;             /* Number of pointers to this structure */
+  int nLock;            /* Number of outstanding locks */
+  int nPending;         /* Number of pending close() operations */
+  int *aPending;        /* Malloced space holding fd's awaiting a close() */
+};
+
+/* 
+** These hash tables map inodes and file descriptors (really, lockKey and
+** openKey structures) into lockInfo and openCnt structures.  Access to 
+** these hash tables must be protected by a mutex.
+*/
+static Hash lockHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0};
+static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0};
+
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+** The locking styles are associated with the different file locking
+** capabilities supported by different file systems.  
+**
+** POSIX locking style fully supports shared and exclusive byte-range locks 
+** ADP locking only supports exclusive byte-range locks
+** FLOCK only supports a single file-global exclusive lock
+** DOTLOCK isn't a true locking style, it refers to the use of a special
+**   file named the same as the database file with a '.lock' extension, this
+**   can be used on file systems that do not offer any reliable file locking
+** NO locking means that no locking will be attempted, this is only used for
+**   read-only file systems currently
+** UNSUPPORTED means that no locking will be attempted, this is only used for
+**   file systems that are known to be unsupported
+*/
+typedef enum {
+  posixLockingStyle = 0,       /* standard posix-advisory locks */
+  afpLockingStyle,             /* use afp locks */
+  flockLockingStyle,           /* use flock() */
+  dotlockLockingStyle,         /* use <file>.lock files */
+  noLockingStyle,              /* useful for read-only file system */
+  unsupportedLockingStyle      /* indicates unsupported file system */
+} sqlite3LockingStyle;
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Helper functions to obtain and relinquish the global mutex.
+*/
+static void enterMutex(){
+  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+static void leaveMutex(){
+  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+
+#if SQLITE_THREADSAFE
+/*
+** This variable records whether or not threads can override each others
+** locks.
+**
+**    0:  No.  Threads cannot override each others locks.
+**    1:  Yes.  Threads can override each others locks.
+**   -1:  We don't know yet.
+**
+** On some systems, we know at compile-time if threads can override each
+** others locks.  On those systems, the SQLITE_THREAD_OVERRIDE_LOCK macro
+** will be set appropriately.  On other systems, we have to check at
+** runtime.  On these latter systems, SQLTIE_THREAD_OVERRIDE_LOCK is
+** undefined.
+**
+** This variable normally has file scope only.  But during testing, we make
+** it a global so that the test code can change its value in order to verify
+** that the right stuff happens in either case.
+*/
+#ifndef SQLITE_THREAD_OVERRIDE_LOCK
+# define SQLITE_THREAD_OVERRIDE_LOCK -1
+#endif
+#ifdef SQLITE_TEST
+int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
+#else
+static int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
+#endif
+
+/*
+** This structure holds information passed into individual test
+** threads by the testThreadLockingBehavior() routine.
+*/
+struct threadTestData {
+  int fd;                /* File to be locked */
+  struct flock lock;     /* The locking operation */
+  int result;            /* Result of the locking operation */
+};
+
+#ifdef SQLITE_LOCK_TRACE
+/*
+** Print out information about all locking operations.
+**
+** This routine is used for troubleshooting locks on multithreaded
+** platforms.  Enable by compiling with the -DSQLITE_LOCK_TRACE
+** command-line option on the compiler.  This code is normally
+** turned off.
+*/
+static int lockTrace(int fd, int op, struct flock *p){
+  char *zOpName, *zType;
+  int s;
+  int savedErrno;
+  if( op==F_GETLK ){
+    zOpName = "GETLK";
+  }else if( op==F_SETLK ){
+    zOpName = "SETLK";
+  }else{
+    s = fcntl(fd, op, p);
+    sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s);
+    return s;
+  }
+  if( p->l_type==F_RDLCK ){
+    zType = "RDLCK";
+  }else if( p->l_type==F_WRLCK ){
+    zType = "WRLCK";
+  }else if( p->l_type==F_UNLCK ){
+    zType = "UNLCK";
+  }else{
+    assert( 0 );
+  }
+  assert( p->l_whence==SEEK_SET );
+  s = fcntl(fd, op, p);
+  savedErrno = errno;
+  sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n",
+     threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len,
+     (int)p->l_pid, s);
+  if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){
+    struct flock l2;
+    l2 = *p;
+    fcntl(fd, F_GETLK, &l2);
+    if( l2.l_type==F_RDLCK ){
+      zType = "RDLCK";
+    }else if( l2.l_type==F_WRLCK ){
+      zType = "WRLCK";
+    }else if( l2.l_type==F_UNLCK ){
+      zType = "UNLCK";
+    }else{
+      assert( 0 );
+    }
+    sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n",
+       zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid);
+  }
+  errno = savedErrno;
+  return s;
+}
+#define fcntl lockTrace
+#endif /* SQLITE_LOCK_TRACE */
+
+/*
+** The testThreadLockingBehavior() routine launches two separate
+** threads on this routine.  This routine attempts to lock a file
+** descriptor then returns.  The success or failure of that attempt
+** allows the testThreadLockingBehavior() procedure to determine
+** whether or not threads can override each others locks.
+*/
+static void *threadLockingTest(void *pArg){
+  struct threadTestData *pData = (struct threadTestData*)pArg;
+  pData->result = fcntl(pData->fd, F_SETLK, &pData->lock);
+  return pArg;
+}
+
+/*
+** This procedure attempts to determine whether or not threads
+** can override each others locks then sets the 
+** threadsOverrideEachOthersLocks variable appropriately.
+*/
+static void testThreadLockingBehavior(int fd_orig){
+  int fd;
+  struct threadTestData d[2];
+  pthread_t t[2];
+
+  fd = dup(fd_orig);
+  if( fd<0 ) return;
+  memset(d, 0, sizeof(d));
+  d[0].fd = fd;
+  d[0].lock.l_type = F_RDLCK;
+  d[0].lock.l_len = 1;
+  d[0].lock.l_start = 0;
+  d[0].lock.l_whence = SEEK_SET;
+  d[1] = d[0];
+  d[1].lock.l_type = F_WRLCK;
+  pthread_create(&t[0], 0, threadLockingTest, &d[0]);
+  pthread_create(&t[1], 0, threadLockingTest, &d[1]);
+  pthread_join(t[0], 0);
+  pthread_join(t[1], 0);
+  close(fd);
+  threadsOverrideEachOthersLocks =  d[0].result==0 && d[1].result==0;
+}
+#endif /* SQLITE_THREADSAFE */
+
+/*
+** Release a lockInfo structure previously allocated by findLockInfo().
+*/
+static void releaseLockInfo(struct lockInfo *pLock){
+  if (pLock == NULL)
+    return;
+  pLock->nRef--;
+  if( pLock->nRef==0 ){
+    sqlite3HashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0);
+    sqlite3_free(pLock);
+  }
+}
+
+/*
+** Release a openCnt structure previously allocated by findLockInfo().
+*/
+static void releaseOpenCnt(struct openCnt *pOpen){
+  if (pOpen == NULL)
+    return;
+  pOpen->nRef--;
+  if( pOpen->nRef==0 ){
+    sqlite3HashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0);
+    free(pOpen->aPending);
+    sqlite3_free(pOpen);
+  }
+}
+
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+** Tests a byte-range locking query to see if byte range locks are 
+** supported, if not we fall back to dotlockLockingStyle.
+*/
+static sqlite3LockingStyle sqlite3TestLockingStyle(
+  const char *filePath, 
+  int fd
+){
+  /* test byte-range lock using fcntl */
+  struct flock lockInfo;
+  
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  
+  if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
+    return posixLockingStyle;
+  } 
+  
+  /* testing for flock can give false positives.  So if if the above test
+  ** fails, then we fall back to using dot-lock style locking.
+  */  
+  return dotlockLockingStyle;
+}
+
+/* 
+** Examines the f_fstypename entry in the statfs structure as returned by 
+** stat() for the file system hosting the database file, assigns the 
+** appropriate locking style based on its value.  These values and 
+** assignments are based on Darwin/OSX behavior and have not been tested on 
+** other systems.
+*/
+static sqlite3LockingStyle sqlite3DetectLockingStyle(
+  const char *filePath, 
+  int fd
+){
+
+#ifdef SQLITE_FIXED_LOCKING_STYLE
+  return (sqlite3LockingStyle)SQLITE_FIXED_LOCKING_STYLE;
+#else
+  struct statfs fsInfo;
+
+  if( statfs(filePath, &fsInfo) == -1 ){
+    return sqlite3TestLockingStyle(filePath, fd);
+  }
+  if( fsInfo.f_flags & MNT_RDONLY ){
+    return noLockingStyle;
+  }
+  if( strcmp(fsInfo.f_fstypename, "hfs")==0 ||
+      strcmp(fsInfo.f_fstypename, "ufs")==0 ){
+    return posixLockingStyle;
+  }
+  if( strcmp(fsInfo.f_fstypename, "afpfs")==0 ){
+    return afpLockingStyle;
+  }
+  if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
+    return sqlite3TestLockingStyle(filePath, fd);
+  }
+  if( strcmp(fsInfo.f_fstypename, "smbfs")==0 ){
+    return flockLockingStyle;
+  }
+  if( strcmp(fsInfo.f_fstypename, "msdos")==0 ){
+    return dotlockLockingStyle;
+  }
+  if( strcmp(fsInfo.f_fstypename, "webdav")==0 ){
+    return unsupportedLockingStyle;
+  }
+  return sqlite3TestLockingStyle(filePath, fd);  
+#endif /* SQLITE_FIXED_LOCKING_STYLE */
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Given a file descriptor, locate lockInfo and openCnt structures that
+** describes that file descriptor.  Create new ones if necessary.  The
+** return values might be uninitialized if an error occurs.
+**
+** Return an appropriate error code.
+*/
+static int findLockInfo(
+  int fd,                      /* The file descriptor used in the key */
+  struct lockInfo **ppLock,    /* Return the lockInfo structure here */
+  struct openCnt **ppOpen      /* Return the openCnt structure here */
+){
+  int rc;
+  struct lockKey key1;
+  struct openKey key2;
+  struct stat statbuf;
+  struct lockInfo *pLock;
+  struct openCnt *pOpen;
+  rc = fstat(fd, &statbuf);
+  if( rc!=0 ){
+#ifdef EOVERFLOW
+    if( errno==EOVERFLOW ) return SQLITE_NOLFS;
+#endif
+    return SQLITE_IOERR;
+  }
+
+  memset(&key1, 0, sizeof(key1));
+  key1.dev = statbuf.st_dev;
+  key1.ino = statbuf.st_ino;
+#if SQLITE_THREADSAFE
+  if( threadsOverrideEachOthersLocks<0 ){
+    testThreadLockingBehavior(fd);
+  }
+  key1.tid = threadsOverrideEachOthersLocks ? 0 : pthread_self();
+#endif
+  memset(&key2, 0, sizeof(key2));
+  key2.dev = statbuf.st_dev;
+  key2.ino = statbuf.st_ino;
+  pLock = (struct lockInfo*)sqlite3HashFind(&lockHash, &key1, sizeof(key1));
+  if( pLock==0 ){
+    struct lockInfo *pOld;
+    pLock = sqlite3_malloc( sizeof(*pLock) );
+    if( pLock==0 ){
+      rc = SQLITE_NOMEM;
+      goto exit_findlockinfo;
+    }
+    pLock->key = key1;
+    pLock->nRef = 1;
+    pLock->cnt = 0;
+    pLock->locktype = 0;
+    pOld = sqlite3HashInsert(&lockHash, &pLock->key, sizeof(key1), pLock);
+    if( pOld!=0 ){
+      assert( pOld==pLock );
+      sqlite3_free(pLock);
+      rc = SQLITE_NOMEM;
+      goto exit_findlockinfo;
+    }
+  }else{
+    pLock->nRef++;
+  }
+  *ppLock = pLock;
+  if( ppOpen!=0 ){
+    pOpen = (struct openCnt*)sqlite3HashFind(&openHash, &key2, sizeof(key2));
+    if( pOpen==0 ){
+      struct openCnt *pOld;
+      pOpen = sqlite3_malloc( sizeof(*pOpen) );
+      if( pOpen==0 ){
+        releaseLockInfo(pLock);
+        rc = SQLITE_NOMEM;
+        goto exit_findlockinfo;
+      }
+      pOpen->key = key2;
+      pOpen->nRef = 1;
+      pOpen->nLock = 0;
+      pOpen->nPending = 0;
+      pOpen->aPending = 0;
+      pOld = sqlite3HashInsert(&openHash, &pOpen->key, sizeof(key2), pOpen);
+      if( pOld!=0 ){
+        assert( pOld==pOpen );
+        sqlite3_free(pOpen);
+        releaseLockInfo(pLock);
+        rc = SQLITE_NOMEM;
+        goto exit_findlockinfo;
+      }
+    }else{
+      pOpen->nRef++;
+    }
+    *ppOpen = pOpen;
+  }
+
+exit_findlockinfo:
+  return rc;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Helper function for printing out trace information from debugging
+** binaries. This returns the string represetation of the supplied
+** integer lock-type.
+*/
+static const char *locktypeName(int locktype){
+  switch( locktype ){
+  case NO_LOCK: return "NONE";
+  case SHARED_LOCK: return "SHARED";
+  case RESERVED_LOCK: return "RESERVED";
+  case PENDING_LOCK: return "PENDING";
+  case EXCLUSIVE_LOCK: return "EXCLUSIVE";
+  }
+  return "ERROR";
+}
+#endif
+
+/*
+** If we are currently in a different thread than the thread that the
+** unixFile argument belongs to, then transfer ownership of the unixFile
+** over to the current thread.
+**
+** A unixFile is only owned by a thread on systems where one thread is
+** unable to override locks created by a different thread.  RedHat9 is
+** an example of such a system.
+**
+** Ownership transfer is only allowed if the unixFile is currently unlocked.
+** If the unixFile is locked and an ownership is wrong, then return
+** SQLITE_MISUSE.  SQLITE_OK is returned if everything works.
+*/
+#if SQLITE_THREADSAFE
+static int transferOwnership(unixFile *pFile){
+  int rc;
+  pthread_t hSelf;
+  if( threadsOverrideEachOthersLocks ){
+    /* Ownership transfers not needed on this system */
+    return SQLITE_OK;
+  }
+  hSelf = pthread_self();
+  if( pthread_equal(pFile->tid, hSelf) ){
+    /* We are still in the same thread */
+    OSTRACE1("No-transfer, same thread\n");
+    return SQLITE_OK;
+  }
+  if( pFile->locktype!=NO_LOCK ){
+    /* We cannot change ownership while we are holding a lock! */
+    return SQLITE_MISUSE;
+  }
+  OSTRACE4("Transfer ownership of %d from %d to %d\n",
+            pFile->h, pFile->tid, hSelf);
+  pFile->tid = hSelf;
+  if (pFile->pLock != NULL) {
+    releaseLockInfo(pFile->pLock);
+    rc = findLockInfo(pFile->h, &pFile->pLock, 0);
+    OSTRACE5("LOCK    %d is now %s(%s,%d)\n", pFile->h,
+           locktypeName(pFile->locktype),
+           locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
+    return rc;
+  } else {
+    return SQLITE_OK;
+  }
+}
+#else
+  /* On single-threaded builds, ownership transfer is a no-op */
+# define transferOwnership(X) SQLITE_OK
+#endif
+
+/*
+** Seek to the offset passed as the second argument, then read cnt 
+** bytes into pBuf. Return the number of bytes actually read.
+**
+** NB:  If you define USE_PREAD or USE_PREAD64, then it might also
+** be necessary to define _XOPEN_SOURCE to be 500.  This varies from
+** one system to another.  Since SQLite does not define USE_PREAD
+** any any form by default, we will not attempt to define _XOPEN_SOURCE.
+** See tickets #2741 and #2681.
+*/
+static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
+  int got;
+  i64 newOffset;
+  TIMER_START;
+#if defined(USE_PREAD)
+  got = pread(id->h, pBuf, cnt, offset);
+  SimulateIOError( got = -1 );
+#elif defined(USE_PREAD64)
+  got = pread64(id->h, pBuf, cnt, offset);
+  SimulateIOError( got = -1 );
+#else
+  newOffset = lseek(id->h, offset, SEEK_SET);
+  SimulateIOError( newOffset-- );
+  if( newOffset!=offset ){
+    return -1;
+  }
+  got = read(id->h, pBuf, cnt);
+#endif
+  TIMER_END;
+  OSTRACE5("READ    %-3d %5d %7lld %d\n", id->h, got, offset, TIMER_ELAPSED);
+  return got;
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int unixRead(
+  sqlite3_file *id, 
+  void *pBuf, 
+  int amt,
+  sqlite3_int64 offset
+){
+  int got;
+  assert( id );
+  got = seekAndRead((unixFile*)id, offset, pBuf, amt);
+  if( got==amt ){
+    return SQLITE_OK;
+  }else if( got<0 ){
+    return SQLITE_IOERR_READ;
+  }else{
+    memset(&((char*)pBuf)[got], 0, amt-got);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+}
+
+/*
+** Seek to the offset in id->offset then read cnt bytes into pBuf.
+** Return the number of bytes actually read.  Update the offset.
+*/
+static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
+  int got;
+  i64 newOffset;
+  TIMER_START;
+#if defined(USE_PREAD)
+  got = pwrite(id->h, pBuf, cnt, offset);
+#elif defined(USE_PREAD64)
+  got = pwrite64(id->h, pBuf, cnt, offset);
+#else
+  newOffset = lseek(id->h, offset, SEEK_SET);
+  if( newOffset!=offset ){
+    return -1;
+  }
+  got = write(id->h, pBuf, cnt);
+#endif
+  TIMER_END;
+  OSTRACE5("WRITE   %-3d %5d %7lld %d\n", id->h, got, offset, TIMER_ELAPSED);
+  return got;
+}
+
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int unixWrite(
+  sqlite3_file *id, 
+  const void *pBuf, 
+  int amt,
+  sqlite3_int64 offset 
+){
+  int wrote = 0;
+  assert( id );
+  assert( amt>0 );
+  while( amt>0 && (wrote = seekAndWrite((unixFile*)id, offset, pBuf, amt))>0 ){
+    amt -= wrote;
+    offset += wrote;
+    pBuf = &((char*)pBuf)[wrote];
+  }
+  SimulateIOError(( wrote=(-1), amt=1 ));
+  SimulateDiskfullError(( wrote=0, amt=1 ));
+  if( amt>0 ){
+    if( wrote<0 ){
+      return SQLITE_IOERR_WRITE;
+    }else{
+      return SQLITE_FULL;
+    }
+  }
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occuring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** Use the fdatasync() API only if the HAVE_FDATASYNC macro is defined.
+** Otherwise use fsync() in its place.
+*/
+#ifndef HAVE_FDATASYNC
+# define fdatasync fsync
+#endif
+
+/*
+** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not
+** the F_FULLFSYNC macro is defined.  F_FULLFSYNC is currently
+** only available on Mac OS X.  But that could change.
+*/
+#ifdef F_FULLFSYNC
+# define HAVE_FULLFSYNC 1
+#else
+# define HAVE_FULLFSYNC 0
+#endif
+
+
+/*
+** The fsync() system call does not work as advertised on many
+** unix systems.  The following procedure is an attempt to make
+** it work better.
+**
+** The SQLITE_NO_SYNC macro disables all fsync()s.  This is useful
+** for testing when we want to run through the test suite quickly.
+** You are strongly advised *not* to deploy with SQLITE_NO_SYNC
+** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash
+** or power failure will likely corrupt the database file.
+*/
+static int full_fsync(int fd, int fullSync, int dataOnly){
+  int rc;
+
+  /* Record the number of times that we do a normal fsync() and 
+  ** FULLSYNC.  This is used during testing to verify that this procedure
+  ** gets called with the correct arguments.
+  */
+#ifdef SQLITE_TEST
+  if( fullSync ) sqlite3_fullsync_count++;
+  sqlite3_sync_count++;
+#endif
+
+  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
+  ** no-op
+  */
+#ifdef SQLITE_NO_SYNC
+  rc = SQLITE_OK;
+#else
+
+#if HAVE_FULLFSYNC
+  if( fullSync ){
+    rc = fcntl(fd, F_FULLFSYNC, 0);
+  }else{
+    rc = 1;
+  }
+  /* If the FULLFSYNC failed, fall back to attempting an fsync().
+   * It shouldn't be possible for fullfsync to fail on the local 
+   * file system (on OSX), so failure indicates that FULLFSYNC
+   * isn't supported for this file system. So, attempt an fsync 
+   * and (for now) ignore the overhead of a superfluous fcntl call.  
+   * It'd be better to detect fullfsync support once and avoid 
+   * the fcntl call every time sync is called.
+   */
+  if( rc ) rc = fsync(fd);
+
+#else 
+  if( dataOnly ){
+    rc = fdatasync(fd);
+  }else{
+    rc = fsync(fd);
+  }
+#endif /* HAVE_FULLFSYNC */
+#endif /* defined(SQLITE_NO_SYNC) */
+
+  return rc;
+}
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+**
+** If dataOnly==0 then both the file itself and its metadata (file
+** size, access time, etc) are synced.  If dataOnly!=0 then only the
+** file data is synced.
+**
+** Under Unix, also make sure that the directory entry for the file
+** has been created by fsync-ing the directory that contains the file.
+** If we do not do this and we encounter a power failure, the directory
+** entry for the journal might not exist after we reboot.  The next
+** SQLite to access the file will not know that the journal exists (because
+** the directory entry for the journal was never created) and the transaction
+** will not roll back - possibly leading to database corruption.
+*/
+static int unixSync(sqlite3_file *id, int flags){
+  int rc;
+  unixFile *pFile = (unixFile*)id;
+
+  int isDataOnly = (flags&SQLITE_SYNC_DATAONLY);
+  int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL;
+
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  assert( pFile );
+  OSTRACE2("SYNC    %-3d\n", pFile->h);
+  rc = full_fsync(pFile->h, isFullsync, isDataOnly);
+  SimulateIOError( rc=1 );
+  if( rc ){
+    return SQLITE_IOERR_FSYNC;
+  }
+  if( pFile->dirfd>=0 ){
+    OSTRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
+            HAVE_FULLFSYNC, isFullsync);
+#ifndef SQLITE_DISABLE_DIRSYNC
+    /* The directory sync is only attempted if full_fsync is
+    ** turned off or unavailable.  If a full_fsync occurred above,
+    ** then the directory sync is superfluous.
+    */
+    if( (!HAVE_FULLFSYNC || !isFullsync) && full_fsync(pFile->dirfd,0,0) ){
+       /*
+       ** We have received multiple reports of fsync() returning
+       ** errors when applied to directories on certain file systems.
+       ** A failed directory sync is not a big deal.  So it seems
+       ** better to ignore the error.  Ticket #1657
+       */
+       /* return SQLITE_IOERR; */
+    }
+#endif
+    close(pFile->dirfd);  /* Only need to sync once, so close the directory */
+    pFile->dirfd = -1;    /* when we are done. */
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int unixTruncate(sqlite3_file *id, i64 nByte){
+  int rc;
+  assert( id );
+  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
+  rc = ftruncate(((unixFile*)id)->h, (off_t)nByte);
+  if( rc ){
+    return SQLITE_IOERR_TRUNCATE;
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int unixFileSize(sqlite3_file *id, i64 *pSize){
+  int rc;
+  struct stat buf;
+  assert( id );
+  rc = fstat(((unixFile*)id)->h, &buf);
+  SimulateIOError( rc=1 );
+  if( rc!=0 ){
+    return SQLITE_IOERR_FSTAT;
+  }
+  *pSize = buf.st_size;
+  return SQLITE_OK;
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, return
+** non-zero.  If the file is unlocked or holds only SHARED locks, then
+** return zero.
+*/
+static int unixCheckReservedLock(sqlite3_file *id){
+  int r = 0;
+  unixFile *pFile = (unixFile*)id;
+
+  assert( pFile );
+  enterMutex(); /* Because pFile->pLock is shared across threads */
+
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->pLock->locktype>SHARED_LOCK ){
+    r = 1;
+  }
+
+  /* Otherwise see if some other process holds it.
+  */
+  if( !r ){
+    struct flock lock;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = RESERVED_BYTE;
+    lock.l_len = 1;
+    lock.l_type = F_WRLCK;
+    fcntl(pFile->h, F_GETLK, &lock);
+    if( lock.l_type!=F_UNLCK ){
+      r = 1;
+    }
+  }
+  
+  leaveMutex();
+  OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);
+
+  return r;
+}
+
+/*
+** Lock the file with the lock specified by parameter locktype - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int unixLock(sqlite3_file *id, int locktype){
+  /* The following describes the implementation of the various locks and
+  ** lock transitions in terms of the POSIX advisory shared and exclusive
+  ** lock primitives (called read-locks and write-locks below, to avoid
+  ** confusion with SQLite lock names). The algorithms are complicated
+  ** slightly in order to be compatible with windows systems simultaneously
+  ** accessing the same database file, in case that is ever required.
+  **
+  ** Symbols defined in os.h indentify the 'pending byte' and the 'reserved
+  ** byte', each single bytes at well known offsets, and the 'shared byte
+  ** range', a range of 510 bytes at a well known offset.
+  **
+  ** To obtain a SHARED lock, a read-lock is obtained on the 'pending
+  ** byte'.  If this is successful, a random byte from the 'shared byte
+  ** range' is read-locked and the lock on the 'pending byte' released.
+  **
+  ** A process may only obtain a RESERVED lock after it has a SHARED lock.
+  ** A RESERVED lock is implemented by grabbing a write-lock on the
+  ** 'reserved byte'. 
+  **
+  ** A process may only obtain a PENDING lock after it has obtained a
+  ** SHARED lock. A PENDING lock is implemented by obtaining a write-lock
+  ** on the 'pending byte'. This ensures that no new SHARED locks can be
+  ** obtained, but existing SHARED locks are allowed to persist. A process
+  ** does not have to obtain a RESERVED lock on the way to a PENDING lock.
+  ** This property is used by the algorithm for rolling back a journal file
+  ** after a crash.
+  **
+  ** An EXCLUSIVE lock, obtained after a PENDING lock is held, is
+  ** implemented by obtaining a write-lock on the entire 'shared byte
+  ** range'. Since all other locks require a read-lock on one of the bytes
+  ** within this range, this ensures that no other locks are held on the
+  ** database. 
+  **
+  ** The reason a single byte cannot be used instead of the 'shared byte
+  ** range' is that some versions of windows do not support read-locks. By
+  ** locking a random byte from a range, concurrent SHARED locks may exist
+  ** even if the locking primitive used is always a write-lock.
+  */
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  struct lockInfo *pLock = pFile->pLock;
+  struct flock lock;
+  int s;
+
+  assert( pFile );
+  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", pFile->h,
+      locktypeName(locktype), locktypeName(pFile->locktype),
+      locktypeName(pLock->locktype), pLock->cnt , getpid());
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the end_lock: exit path, as
+  ** enterMutex() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
+            locktypeName(locktype));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+  /* This mutex is needed because pFile->pLock is shared across threads
+  */
+  enterMutex();
+
+  /* Make sure the current thread owns the pFile.
+  */
+  rc = transferOwnership(pFile);
+  if( rc!=SQLITE_OK ){
+    leaveMutex();
+    return rc;
+  }
+  pLock = pFile->pLock;
+
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
+  */
+  if( (pFile->locktype!=pLock->locktype && 
+          (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
+  ){
+    rc = SQLITE_BUSY;
+    goto end_lock;
+  }
+
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( locktype==SHARED_LOCK && 
+      (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
+    assert( locktype==SHARED_LOCK );
+    assert( pFile->locktype==0 );
+    assert( pLock->cnt>0 );
+    pFile->locktype = SHARED_LOCK;
+    pLock->cnt++;
+    pFile->pOpen->nLock++;
+    goto end_lock;
+  }
+
+  lock.l_len = 1L;
+
+  lock.l_whence = SEEK_SET;
+
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  if( locktype==SHARED_LOCK 
+      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
+  ){
+    lock.l_type = (locktype==SHARED_LOCK?F_RDLCK:F_WRLCK);
+    lock.l_start = PENDING_BYTE;
+    s = fcntl(pFile->h, F_SETLK, &lock);
+    if( s==(-1) ){
+      rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
+      goto end_lock;
+    }
+  }
+
+
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( locktype==SHARED_LOCK ){
+    assert( pLock->cnt==0 );
+    assert( pLock->locktype==0 );
+
+    /* Now get the read-lock */
+    lock.l_start = SHARED_FIRST;
+    lock.l_len = SHARED_SIZE;
+    s = fcntl(pFile->h, F_SETLK, &lock);
+
+    /* Drop the temporary PENDING lock */
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 1L;
+    lock.l_type = F_UNLCK;
+    if( fcntl(pFile->h, F_SETLK, &lock)!=0 ){
+      rc = SQLITE_IOERR_UNLOCK;  /* This should never happen */
+      goto end_lock;
+    }
+    if( s==(-1) ){
+      rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
+    }else{
+      pFile->locktype = SHARED_LOCK;
+      pFile->pOpen->nLock++;
+      pLock->cnt = 1;
+    }
+  }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+    ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    assert( 0!=pFile->locktype );
+    lock.l_type = F_WRLCK;
+    switch( locktype ){
+      case RESERVED_LOCK:
+        lock.l_start = RESERVED_BYTE;
+        break;
+      case EXCLUSIVE_LOCK:
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = SHARED_SIZE;
+        break;
+      default:
+        assert(0);
+    }
+    s = fcntl(pFile->h, F_SETLK, &lock);
+    if( s==(-1) ){
+      rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
+    }
+  }
+  
+  if( rc==SQLITE_OK ){
+    pFile->locktype = locktype;
+    pLock->locktype = locktype;
+  }else if( locktype==EXCLUSIVE_LOCK ){
+    pFile->locktype = PENDING_LOCK;
+    pLock->locktype = PENDING_LOCK;
+  }
+
+end_lock:
+  leaveMutex();
+  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
+      rc==SQLITE_OK ? "ok" : "failed");
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int unixUnlock(sqlite3_file *id, int locktype){
+  struct lockInfo *pLock;
+  struct flock lock;
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  int h;
+
+  assert( pFile );
+  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d\n", pFile->h, locktype,
+      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());
+
+  assert( locktype<=SHARED_LOCK );
+  if( pFile->locktype<=locktype ){
+    return SQLITE_OK;
+  }
+  if( CHECK_THREADID(pFile) ){
+    return SQLITE_MISUSE;
+  }
+  enterMutex();
+  h = pFile->h;
+  pLock = pFile->pLock;
+  assert( pLock->cnt!=0 );
+  if( pFile->locktype>SHARED_LOCK ){
+    assert( pLock->locktype==pFile->locktype );
+    SimulateIOErrorBenign(1);
+    SimulateIOError( h=(-1) )
+    SimulateIOErrorBenign(0);
+    if( locktype==SHARED_LOCK ){
+      lock.l_type = F_RDLCK;
+      lock.l_whence = SEEK_SET;
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+      if( fcntl(h, F_SETLK, &lock)==(-1) ){
+        rc = SQLITE_IOERR_RDLOCK;
+      }
+    }
+    lock.l_type = F_UNLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
+    if( fcntl(h, F_SETLK, &lock)!=(-1) ){
+      pLock->locktype = SHARED_LOCK;
+    }else{
+      rc = SQLITE_IOERR_UNLOCK;
+    }
+  }
+  if( locktype==NO_LOCK ){
+    struct openCnt *pOpen;
+
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    pLock->cnt--;
+    if( pLock->cnt==0 ){
+      lock.l_type = F_UNLCK;
+      lock.l_whence = SEEK_SET;
+      lock.l_start = lock.l_len = 0L;
+      SimulateIOErrorBenign(1);
+      SimulateIOError( h=(-1) )
+      SimulateIOErrorBenign(0);
+      if( fcntl(h, F_SETLK, &lock)!=(-1) ){
+        pLock->locktype = NO_LOCK;
+      }else{
+        rc = SQLITE_IOERR_UNLOCK;
+        pLock->cnt = 1;
+      }
+    }
+
+    /* Decrement the count of locks against this same file.  When the
+    ** count reaches zero, close any other file descriptors whose close
+    ** was deferred because of outstanding locks.
+    */
+    if( rc==SQLITE_OK ){
+      pOpen = pFile->pOpen;
+      pOpen->nLock--;
+      assert( pOpen->nLock>=0 );
+      if( pOpen->nLock==0 && pOpen->nPending>0 ){
+        int i;
+        for(i=0; i<pOpen->nPending; i++){
+          close(pOpen->aPending[i]);
+        }
+        free(pOpen->aPending);
+        pOpen->nPending = 0;
+        pOpen->aPending = 0;
+      }
+    }
+  }
+  leaveMutex();
+  if( rc==SQLITE_OK ) pFile->locktype = locktype;
+  return rc;
+}
+
+/*
+** Close a file.
+*/
+static int unixClose(sqlite3_file *id){
+  unixFile *pFile = (unixFile *)id;
+  if( !pFile ) return SQLITE_OK;
+  unixUnlock(id, NO_LOCK);
+  if( pFile->dirfd>=0 ) close(pFile->dirfd);
+  pFile->dirfd = -1;
+  enterMutex();
+
+  if( pFile->pOpen->nLock ){
+    /* If there are outstanding locks, do not actually close the file just
+    ** yet because that would clear those locks.  Instead, add the file
+    ** descriptor to pOpen->aPending.  It will be automatically closed when
+    ** the last lock is cleared.
+    */
+    int *aNew;
+    struct openCnt *pOpen = pFile->pOpen;
+    aNew = realloc( pOpen->aPending, (pOpen->nPending+1)*sizeof(int) );
+    if( aNew==0 ){
+      /* If a malloc fails, just leak the file descriptor */
+    }else{
+      pOpen->aPending = aNew;
+      pOpen->aPending[pOpen->nPending] = pFile->h;
+      pOpen->nPending++;
+    }
+  }else{
+    /* There are no outstanding locks so we can close the file immediately */
+    close(pFile->h);
+  }
+  releaseLockInfo(pFile->pLock);
+  releaseOpenCnt(pFile->pOpen);
+
+  leaveMutex();
+  OSTRACE2("CLOSE   %-3d\n", pFile->h);
+  OpenCounter(-1);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+#pragma mark AFP Support
+
+/*
+ ** The afpLockingContext structure contains all afp lock specific state
+ */
+typedef struct afpLockingContext afpLockingContext;
+struct afpLockingContext {
+  unsigned long long sharedLockByte;
+  const char *filePath;
+};
+
+struct ByteRangeLockPB2
+{
+  unsigned long long offset;        /* offset to first byte to lock */
+  unsigned long long length;        /* nbr of bytes to lock */
+  unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */
+  unsigned char unLockFlag;         /* 1 = unlock, 0 = lock */
+  unsigned char startEndFlag;       /* 1=rel to end of fork, 0=rel to start */
+  int fd;                           /* file desc to assoc this lock with */
+};
+
+#define afpfsByteRangeLock2FSCTL        _IOWR('z', 23, struct ByteRangeLockPB2)
+
+/* 
+** Return 0 on success, 1 on failure.  To match the behavior of the 
+** normal posix file locking (used in unixLock for example), we should 
+** provide 'richer' return codes - specifically to differentiate between
+** 'file busy' and 'file system error' results.
+*/
+static int _AFPFSSetLock(
+  const char *path, 
+  int fd, 
+  unsigned long long offset, 
+  unsigned long long length, 
+  int setLockFlag
+){
+  struct ByteRangeLockPB2       pb;
+  int                     err;
+  
+  pb.unLockFlag = setLockFlag ? 0 : 1;
+  pb.startEndFlag = 0;
+  pb.offset = offset;
+  pb.length = length; 
+  pb.fd = fd;
+  OSTRACE5("AFPLOCK setting lock %s for %d in range %llx:%llx\n", 
+    (setLockFlag?"ON":"OFF"), fd, offset, length);
+  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
+  if ( err==-1 ) {
+    OSTRACE4("AFPLOCK failed to fsctl() '%s' %d %s\n", path, errno, 
+      strerror(errno));
+    return 1; /* error */
+  } else {
+    return 0;
+  }
+}
+
+/*
+ ** This routine checks if there is a RESERVED lock held on the specified
+ ** file by this or any other process. If such a lock is held, return
+ ** non-zero.  If the file is unlocked or holds only SHARED locks, then
+ ** return zero.
+ */
+static int afpUnixCheckReservedLock(sqlite3_file *id){
+  int r = 0;
+  unixFile *pFile = (unixFile*)id;
+  
+  assert( pFile ); 
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->locktype>SHARED_LOCK ){
+    r = 1;
+  }
+  
+  /* Otherwise see if some other process holds it.
+   */
+  if ( !r ) {
+    /* lock the byte */
+    int failed = _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1,1);  
+    if (failed) {
+      /* if we failed to get the lock then someone else must have it */
+      r = 1;
+    } else {
+      /* if we succeeded in taking the reserved lock, unlock it to restore
+      ** the original state */
+      _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0);
+    }
+  }
+  OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);
+  
+  return r;
+}
+
+/* AFP-style locking following the behavior of unixLock, see the unixLock 
+** function comments for details of lock management. */
+static int afpUnixLock(sqlite3_file *id, int locktype){
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  int gotPendingLock = 0;
+  
+  assert( pFile );
+  OSTRACE5("LOCK    %d %s was %s pid=%d\n", pFile->h,
+         locktypeName(locktype), locktypeName(pFile->locktype), getpid());
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
+  ** enterMutex() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
+           locktypeName(locktype));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+  
+  /* This mutex is needed because pFile->pLock is shared across threads
+  */
+  enterMutex();
+
+  /* Make sure the current thread owns the pFile.
+  */
+  rc = transferOwnership(pFile);
+  if( rc!=SQLITE_OK ){
+    leaveMutex();
+    return rc;
+  }
+    
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  if( locktype==SHARED_LOCK 
+      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
+  ){
+    int failed;
+    failed = _AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 1);
+    if (failed) {
+      rc = SQLITE_BUSY;
+      goto afp_end_lock;
+    }
+  }
+  
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( locktype==SHARED_LOCK ){
+    int lk, failed;
+    int tries = 0;
+    
+    /* Now get the read-lock */
+    /* note that the quality of the randomness doesn't matter that much */
+    lk = random(); 
+    context->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
+    failed = _AFPFSSetLock(context->filePath, pFile->h, 
+      SHARED_FIRST+context->sharedLockByte, 1, 1);
+    
+    /* Drop the temporary PENDING lock */
+    if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)) {
+      rc = SQLITE_IOERR_UNLOCK;  /* This should never happen */
+      goto afp_end_lock;
+    }
+    
+    if( failed ){
+      rc = SQLITE_BUSY;
+    } else {
+      pFile->locktype = SHARED_LOCK;
+    }
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    int failed = 0;
+    assert( 0!=pFile->locktype );
+    if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
+        /* Acquire a RESERVED lock */
+        failed = _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1,1);
+    }
+    if (!failed && locktype == EXCLUSIVE_LOCK) {
+      /* Acquire an EXCLUSIVE lock */
+        
+      /* Remove the shared lock before trying the range.  we'll need to 
+      ** reestablish the shared lock if we can't get the  afpUnixUnlock
+      */
+      if (!_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST +
+                         context->sharedLockByte, 1, 0)) {
+        /* now attemmpt to get the exclusive lock range */
+        failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST, 
+                               SHARED_SIZE, 1);
+        if (failed && _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST +
+                                    context->sharedLockByte, 1, 1)) {
+          rc = SQLITE_IOERR_RDLOCK; /* this should never happen */
+        }
+      } else {
+        /* */
+        rc = SQLITE_IOERR_UNLOCK; /* this should never happen */
+      }
+    }
+    if( failed && rc == SQLITE_OK){
+      rc = SQLITE_BUSY;
+    }
+  }
+  
+  if( rc==SQLITE_OK ){
+    pFile->locktype = locktype;
+  }else if( locktype==EXCLUSIVE_LOCK ){
+    pFile->locktype = PENDING_LOCK;
+  }
+  
+afp_end_lock:
+  leaveMutex();
+  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
+         rc==SQLITE_OK ? "ok" : "failed");
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int afpUnixUnlock(sqlite3_file *id, int locktype) {
+  struct flock lock;
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+
+  assert( pFile );
+  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
+         pFile->locktype, getpid());
+  
+  assert( locktype<=SHARED_LOCK );
+  if( pFile->locktype<=locktype ){
+    return SQLITE_OK;
+  }
+  if( CHECK_THREADID(pFile) ){
+    return SQLITE_MISUSE;
+  }
+  enterMutex();
+  if( pFile->locktype>SHARED_LOCK ){
+    if( locktype==SHARED_LOCK ){
+      int failed = 0;
+
+      /* unlock the exclusive range - then re-establish the shared lock */
+      if (pFile->locktype==EXCLUSIVE_LOCK) {
+        failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST, 
+                                 SHARED_SIZE, 0);
+        if (!failed) {
+          /* successfully removed the exclusive lock */
+          if (_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST+
+                            context->sharedLockByte, 1, 1)) {
+            /* failed to re-establish our shared lock */
+            rc = SQLITE_IOERR_RDLOCK; /* This should never happen */
+          }
+        } else {
+          /* This should never happen - failed to unlock the exclusive range */
+          rc = SQLITE_IOERR_UNLOCK;
+        } 
+      }
+    }
+    if (rc == SQLITE_OK && pFile->locktype>=PENDING_LOCK) {
+      if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)){
+        /* failed to release the pending lock */
+        rc = SQLITE_IOERR_UNLOCK; /* This should never happen */
+      }
+    } 
+    if (rc == SQLITE_OK && pFile->locktype>=RESERVED_LOCK) {
+      if (_AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0)) {
+        /* failed to release the reserved lock */
+        rc = SQLITE_IOERR_UNLOCK;  /* This should never happen */
+      }
+    } 
+  }
+  if( locktype==NO_LOCK ){
+    int failed = _AFPFSSetLock(context->filePath, pFile->h, 
+                               SHARED_FIRST + context->sharedLockByte, 1, 0);
+    if (failed) {
+      rc = SQLITE_IOERR_UNLOCK;  /* This should never happen */
+    }
+  }
+  if (rc == SQLITE_OK)
+    pFile->locktype = locktype;
+  leaveMutex();
+  return rc;
+}
+
+/*
+** Close a file & cleanup AFP specific locking context 
+*/
+static int afpUnixClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+
+  if( !pFile ) return SQLITE_OK;
+  afpUnixUnlock(id, NO_LOCK);
+  sqlite3_free(pFile->lockingContext);
+  if( pFile->dirfd>=0 ) close(pFile->dirfd);
+  pFile->dirfd = -1;
+  enterMutex();
+  close(pFile->h);
+  leaveMutex();
+  OSTRACE2("CLOSE   %-3d\n", pFile->h);
+  OpenCounter(-1);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+
+#pragma mark flock() style locking
+
+/*
+** The flockLockingContext is not used
+*/
+typedef void flockLockingContext;
+
+static int flockUnixCheckReservedLock(sqlite3_file *id){
+  unixFile *pFile = (unixFile*)id;
+  
+  if (pFile->locktype == RESERVED_LOCK) {
+    return 1; /* already have a reserved lock */
+  } else {
+    /* attempt to get the lock */
+    int rc = flock(pFile->h, LOCK_EX | LOCK_NB);
+    if (!rc) {
+      /* got the lock, unlock it */
+      flock(pFile->h, LOCK_UN);
+      return 0;  /* no one has it reserved */
+    }
+    return 1; /* someone else might have it reserved */
+  }
+}
+
+static int flockUnixLock(sqlite3_file *id, int locktype) {
+  unixFile *pFile = (unixFile*)id;
+  
+  /* if we already have a lock, it is exclusive.  
+  ** Just adjust level and punt on outta here. */
+  if (pFile->locktype > NO_LOCK) {
+    pFile->locktype = locktype;
+    return SQLITE_OK;
+  }
+  
+  /* grab an exclusive lock */
+  int rc = flock(pFile->h, LOCK_EX | LOCK_NB);
+  if (rc) {
+    /* didn't get, must be busy */
+    return SQLITE_BUSY;
+  } else {
+    /* got it, set the type and return ok */
+    pFile->locktype = locktype;
+    return SQLITE_OK;
+  }
+}
+
+static int flockUnixUnlock(sqlite3_file *id, int locktype) {
+  unixFile *pFile = (unixFile*)id;
+  
+  assert( locktype<=SHARED_LOCK );
+  
+  /* no-op if possible */
+  if( pFile->locktype==locktype ){
+    return SQLITE_OK;
+  }
+  
+  /* shared can just be set because we always have an exclusive */
+  if (locktype==SHARED_LOCK) {
+    pFile->locktype = locktype;
+    return SQLITE_OK;
+  }
+  
+  /* no, really, unlock. */
+  int rc = flock(pFile->h, LOCK_UN);
+  if (rc)
+    return SQLITE_IOERR_UNLOCK;
+  else {
+    pFile->locktype = NO_LOCK;
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Close a file.
+*/
+static int flockUnixClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  
+  if( !pFile ) return SQLITE_OK;
+  flockUnixUnlock(id, NO_LOCK);
+  
+  if( pFile->dirfd>=0 ) close(pFile->dirfd);
+  pFile->dirfd = -1;
+
+  enterMutex();
+  close(pFile->h);  
+  leaveMutex();
+  OSTRACE2("CLOSE   %-3d\n", pFile->h);
+  OpenCounter(-1);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+#pragma mark Old-School .lock file based locking
+
+/*
+** The dotlockLockingContext structure contains all dotlock (.lock) lock
+** specific state
+*/
+typedef struct dotlockLockingContext dotlockLockingContext;
+struct dotlockLockingContext {
+  char *lockPath;
+};
+
+
+static int dotlockUnixCheckReservedLock(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  dotlockLockingContext *context;
+
+  context = (dotlockLockingContext*)pFile->lockingContext;
+  if (pFile->locktype == RESERVED_LOCK) {
+    return 1; /* already have a reserved lock */
+  } else {
+    struct stat statBuf;
+    if (lstat(context->lockPath,&statBuf) == 0){
+      /* file exists, someone else has the lock */
+      return 1;
+    }else{
+      /* file does not exist, we could have it if we want it */
+      return 0;
+    }
+  }
+}
+
+static int dotlockUnixLock(sqlite3_file *id, int locktype) {
+  unixFile *pFile = (unixFile*)id;
+  dotlockLockingContext *context;
+  int fd;
+
+  context = (dotlockLockingContext*)pFile->lockingContext;
+  
+  /* if we already have a lock, it is exclusive.  
+  ** Just adjust level and punt on outta here. */
+  if (pFile->locktype > NO_LOCK) {
+    pFile->locktype = locktype;
+    
+    /* Always update the timestamp on the old file */
+    utimes(context->lockPath,NULL);
+    return SQLITE_OK;
+  }
+  
+  /* check to see if lock file already exists */
+  struct stat statBuf;
+  if (lstat(context->lockPath,&statBuf) == 0){
+    return SQLITE_BUSY; /* it does, busy */
+  }
+  
+  /* grab an exclusive lock */
+  fd = open(context->lockPath,O_RDONLY|O_CREAT|O_EXCL,0600);
+  if( fd<0 ){
+    /* failed to open/create the file, someone else may have stolen the lock */
+    return SQLITE_BUSY; 
+  }
+  close(fd);
+  
+  /* got it, set the type and return ok */
+  pFile->locktype = locktype;
+  return SQLITE_OK;
+}
+
+static int dotlockUnixUnlock(sqlite3_file *id, int locktype) {
+  unixFile *pFile = (unixFile*)id;
+  dotlockLockingContext *context;
+
+  context = (dotlockLockingContext*)pFile->lockingContext;
+  
+  assert( locktype<=SHARED_LOCK );
+  
+  /* no-op if possible */
+  if( pFile->locktype==locktype ){
+    return SQLITE_OK;
+  }
+  
+  /* shared can just be set because we always have an exclusive */
+  if (locktype==SHARED_LOCK) {
+    pFile->locktype = locktype;
+    return SQLITE_OK;
+  }
+  
+  /* no, really, unlock. */
+  unlink(context->lockPath);
+  pFile->locktype = NO_LOCK;
+  return SQLITE_OK;
+}
+
+/*
+ ** Close a file.
+ */
+static int dotlockUnixClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  
+  if( !pFile ) return SQLITE_OK;
+  dotlockUnixUnlock(id, NO_LOCK);
+  sqlite3_free(pFile->lockingContext);
+  if( pFile->dirfd>=0 ) close(pFile->dirfd);
+  pFile->dirfd = -1;
+  enterMutex();  
+  close(pFile->h);
+  leaveMutex();
+  OSTRACE2("CLOSE   %-3d\n", pFile->h);
+  OpenCounter(-1);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+
+#pragma mark No locking
+
+/*
+** The nolockLockingContext is void
+*/
+typedef void nolockLockingContext;
+
+static int nolockUnixCheckReservedLock(sqlite3_file *id) {
+  return 0;
+}
+
+static int nolockUnixLock(sqlite3_file *id, int locktype) {
+  return SQLITE_OK;
+}
+
+static int nolockUnixUnlock(sqlite3_file *id, int locktype) {
+  return SQLITE_OK;
+}
+
+/*
+** Close a file.
+*/
+static int nolockUnixClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  
+  if( !pFile ) return SQLITE_OK;
+  if( pFile->dirfd>=0 ) close(pFile->dirfd);
+  pFile->dirfd = -1;
+  enterMutex();
+  close(pFile->h);
+  leaveMutex();
+  OSTRACE2("CLOSE   %-3d\n", pFile->h);
+  OpenCounter(-1);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+
+/*
+** Information and control of an open file handle.
+*/
+static int unixFileControl(sqlite3_file *id, int op, void *pArg){
+  switch( op ){
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = ((unixFile*)id)->locktype;
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int unixSectorSize(sqlite3_file *id){
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+/*
+** Return the device characteristics for the file. This is always 0.
+*/
+static int unixDeviceCharacteristics(sqlite3_file *id){
+  return 0;
+}
+
+/*
+** This vector defines all the methods that can operate on an sqlite3_file
+** for unix.
+*/
+static const sqlite3_io_methods sqlite3UnixIoMethod = {
+  1,                        /* iVersion */
+  unixClose,
+  unixRead,
+  unixWrite,
+  unixTruncate,
+  unixSync,
+  unixFileSize,
+  unixLock,
+  unixUnlock,
+  unixCheckReservedLock,
+  unixFileControl,
+  unixSectorSize,
+  unixDeviceCharacteristics
+};
+
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+** This vector defines all the methods that can operate on an sqlite3_file
+** for unix with AFP style file locking.
+*/
+static const sqlite3_io_methods sqlite3AFPLockingUnixIoMethod = {
+  1,                        /* iVersion */
+  afpUnixClose,
+  unixRead,
+  unixWrite,
+  unixTruncate,
+  unixSync,
+  unixFileSize,
+  afpUnixLock,
+  afpUnixUnlock,
+  afpUnixCheckReservedLock,
+  unixFileControl,
+  unixSectorSize,
+  unixDeviceCharacteristics
+};
+
+/*
+** This vector defines all the methods that can operate on an sqlite3_file
+** for unix with flock() style file locking.
+*/
+static const sqlite3_io_methods sqlite3FlockLockingUnixIoMethod = {
+  1,                        /* iVersion */
+  flockUnixClose,
+  unixRead,
+  unixWrite,
+  unixTruncate,
+  unixSync,
+  unixFileSize,
+  flockUnixLock,
+  flockUnixUnlock,
+  flockUnixCheckReservedLock,
+  unixFileControl,
+  unixSectorSize,
+  unixDeviceCharacteristics
+};
+
+/*
+** This vector defines all the methods that can operate on an sqlite3_file
+** for unix with dotlock style file locking.
+*/
+static const sqlite3_io_methods sqlite3DotlockLockingUnixIoMethod = {
+  1,                        /* iVersion */
+  dotlockUnixClose,
+  unixRead,
+  unixWrite,
+  unixTruncate,
+  unixSync,
+  unixFileSize,
+  dotlockUnixLock,
+  dotlockUnixUnlock,
+  dotlockUnixCheckReservedLock,
+  unixFileControl,
+  unixSectorSize,
+  unixDeviceCharacteristics
+};
+
+/*
+** This vector defines all the methods that can operate on an sqlite3_file
+** for unix with nolock style file locking.
+*/
+static const sqlite3_io_methods sqlite3NolockLockingUnixIoMethod = {
+  1,                        /* iVersion */
+  nolockUnixClose,
+  unixRead,
+  unixWrite,
+  unixTruncate,
+  unixSync,
+  unixFileSize,
+  nolockUnixLock,
+  nolockUnixUnlock,
+  nolockUnixCheckReservedLock,
+  unixFileControl,
+  unixSectorSize,
+  unixDeviceCharacteristics
+};
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Allocate memory for a new unixFile and initialize that unixFile.
+** Write a pointer to the new unixFile into *pId.
+** If we run out of memory, close the file and return an error.
+*/
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/* 
+** When locking extensions are enabled, the filepath and locking style 
+** are needed to determine the unixFile pMethod to use for locking operations.
+** The locking-style specific lockingContext data structure is created 
+** and assigned here also.
+*/
+static int fillInUnixFile(
+  int h,                  /* Open file descriptor of file being opened */
+  int dirfd,              /* Directory file descriptor */
+  sqlite3_file *pId,      /* Write to the unixFile structure here */
+  const char *zFilename   /* Name of the file being opened */
+){
+  sqlite3LockingStyle lockingStyle;
+  unixFile *pNew = (unixFile *)pId;
+  int rc;
+
+#ifdef FD_CLOEXEC
+  fcntl(h, F_SETFD, fcntl(h, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+
+  lockingStyle = sqlite3DetectLockingStyle(zFilename, h);
+  if ( lockingStyle==posixLockingStyle ){
+    enterMutex();
+    rc = findLockInfo(h, &pNew->pLock, &pNew->pOpen);
+    leaveMutex();
+    if( rc ){
+      if( dirfd>=0 ) close(dirfd);
+      close(h);
+      return rc;
+    }
+  } else {
+    /*  pLock and pOpen are only used for posix advisory locking */
+    pNew->pLock = NULL;
+    pNew->pOpen = NULL;
+  }
+
+  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);    
+  pNew->dirfd = -1;
+  pNew->h = h;
+  pNew->dirfd = dirfd;
+  SET_THREADID(pNew);
+    
+  switch(lockingStyle) {
+    case afpLockingStyle: {
+      /* afp locking uses the file path so it needs to be included in
+      ** the afpLockingContext */
+      afpLockingContext *context;
+      pNew->pMethod = &sqlite3AFPLockingUnixIoMethod;
+      pNew->lockingContext = context = sqlite3_malloc( sizeof(*context) );
+      if( context==0 ){
+        close(h);
+        if( dirfd>=0 ) close(dirfd);
+        return SQLITE_NOMEM;
+      }
+
+      /* NB: zFilename exists and remains valid until the file is closed
+      ** according to requirement F11141.  So we do not need to make a
+      ** copy of the filename. */
+      context->filePath = zFilename;
+      srandomdev();
+      break;
+    }
+    case flockLockingStyle:
+      /* flock locking doesn't need additional lockingContext information */
+      pNew->pMethod = &sqlite3FlockLockingUnixIoMethod;
+      break;
+    case dotlockLockingStyle: {
+      /* dotlock locking uses the file path so it needs to be included in
+      ** the dotlockLockingContext */
+      dotlockLockingContext *context;
+      int nFilename;
+      nFilename = strlen(zFilename);
+      pNew->pMethod = &sqlite3DotlockLockingUnixIoMethod;
+      pNew->lockingContext = context = 
+         sqlite3_malloc( sizeof(*context) + nFilename + 6 );
+      if( context==0 ){
+        close(h);
+        if( dirfd>=0 ) close(dirfd);
+        return SQLITE_NOMEM;
+      }
+      context->lockPath = (char*)&context[1];
+      sqlite3_snprintf(nFilename, context->lockPath,
+                       "%s.lock", zFilename);
+      break;
+    }
+    case posixLockingStyle:
+      /* posix locking doesn't need additional lockingContext information */
+      pNew->pMethod = &sqlite3UnixIoMethod;
+      break;
+    case noLockingStyle:
+    case unsupportedLockingStyle:
+    default: 
+      pNew->pMethod = &sqlite3NolockLockingUnixIoMethod;
+  }
+  OpenCounter(+1);
+  return SQLITE_OK;
+}
+#else /* SQLITE_ENABLE_LOCKING_STYLE */
+static int fillInUnixFile(
+  int h,                 /* Open file descriptor on file being opened */
+  int dirfd,
+  sqlite3_file *pId,     /* Write to the unixFile structure here */
+  const char *zFilename  /* Name of the file being opened */
+){
+  unixFile *pNew = (unixFile *)pId;
+  int rc;
+
+#ifdef FD_CLOEXEC
+  fcntl(h, F_SETFD, fcntl(h, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+
+  enterMutex();
+  rc = findLockInfo(h, &pNew->pLock, &pNew->pOpen);
+  leaveMutex();
+  if( rc ){
+    if( dirfd>=0 ) close(dirfd);
+    close(h);
+    return rc;
+  }
+
+  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);
+  pNew->dirfd = -1;
+  pNew->h = h;
+  pNew->dirfd = dirfd;
+  SET_THREADID(pNew);
+
+  pNew->pMethod = &sqlite3UnixIoMethod;
+  OpenCounter(+1);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Open a file descriptor to the directory containing file zFilename.
+** If successful, *pFd is set to the opened file descriptor and
+** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
+** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
+** value.
+**
+** If SQLITE_OK is returned, the caller is responsible for closing
+** the file descriptor *pFd using close().
+*/
+static int openDirectory(const char *zFilename, int *pFd){
+  int ii;
+  int fd = -1;
+  char zDirname[MAX_PATHNAME+1];
+
+  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
+  for(ii=strlen(zDirname); ii>=0 && zDirname[ii]!='/'; ii--);
+  if( ii>0 ){
+    zDirname[ii] = '\0';
+    fd = open(zDirname, O_RDONLY|O_BINARY, 0);
+    if( fd>=0 ){
+#ifdef FD_CLOEXEC
+      fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+      OSTRACE3("OPENDIR %-3d %s\n", fd, zDirname);
+    }
+  }
+  *pFd = fd;
+  return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN);
+}
+
+/*
+** Open the file zPath.
+** 
+** Previously, the SQLite OS layer used three functions in place of this
+** one:
+**
+**     sqlite3OsOpenReadWrite();
+**     sqlite3OsOpenReadOnly();
+**     sqlite3OsOpenExclusive();
+**
+** These calls correspond to the following combinations of flags:
+**
+**     ReadWrite() ->     (READWRITE | CREATE)
+**     ReadOnly()  ->     (READONLY) 
+**     OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE)
+**
+** The old OpenExclusive() accepted a boolean argument - "delFlag". If
+** true, the file was configured to be automatically deleted when the
+** file handle closed. To achieve the same effect using this new 
+** interface, add the DELETEONCLOSE flag to those specified above for 
+** OpenExclusive().
+*/
+static int unixOpen(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  sqlite3_file *pFile,
+  int flags,
+  int *pOutFlags
+){
+  int fd = 0;                    /* File descriptor returned by open() */
+  int dirfd = -1;                /* Directory file descriptor */
+  int oflags = 0;                /* Flags to pass to open() */
+  int eType = flags&0xFFFFFF00;  /* Type of file to open */
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+
+  /* If creating a master or main-file journal, this function will open
+  ** a file-descriptor on the directory too. The first time unixSync()
+  ** is called the directory file descriptor will be fsync()ed and close()d.
+  */
+  int isOpenDirectory = (isCreate && 
+      (eType==SQLITE_OPEN_MASTER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL)
+  );
+
+  /* Check the following statements are true: 
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+
+  /* The main DB, main journal, and master journal are never automatically
+  ** deleted
+  */
+  assert( eType!=SQLITE_OPEN_MAIN_DB || !isDelete );
+  assert( eType!=SQLITE_OPEN_MAIN_JOURNAL || !isDelete );
+  assert( eType!=SQLITE_OPEN_MASTER_JOURNAL || !isDelete );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB 
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL 
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_MASTER_JOURNAL 
+       || eType==SQLITE_OPEN_TRANSIENT_DB
+  );
+
+  if( isReadonly )  oflags |= O_RDONLY;
+  if( isReadWrite ) oflags |= O_RDWR;
+  if( isCreate )    oflags |= O_CREAT;
+  if( isExclusive ) oflags |= (O_EXCL|O_NOFOLLOW);
+  oflags |= (O_LARGEFILE|O_BINARY);
+
+  memset(pFile, 0, sizeof(unixFile));
+  fd = open(zPath, oflags, isDelete?0600:SQLITE_DEFAULT_FILE_PERMISSIONS);
+  if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
+    /* Failed to open the file for read/write access. Try read-only. */
+    flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
+    flags |= SQLITE_OPEN_READONLY;
+    return unixOpen(pVfs, zPath, pFile, flags, pOutFlags);
+  }
+  if( fd<0 ){
+    return SQLITE_CANTOPEN;
+  }
+  if( isDelete ){
+    unlink(zPath);
+  }
+  if( pOutFlags ){
+    *pOutFlags = flags;
+  }
+
+  assert(fd!=0);
+  if( isOpenDirectory ){
+    int rc = openDirectory(zPath, &dirfd);
+    if( rc!=SQLITE_OK ){
+      close(fd);
+      return rc;
+    }
+  }
+  return fillInUnixFile(fd, dirfd, pFile, zPath);
+}
+
+/*
+** Delete the file at zPath. If the dirSync argument is true, fsync()
+** the directory after deleting the file.
+*/
+static int unixDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  int rc = SQLITE_OK;
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  unlink(zPath);
+  if( dirSync ){
+    int fd;
+    rc = openDirectory(zPath, &fd);
+    if( rc==SQLITE_OK ){
+      if( fsync(fd) ){
+        rc = SQLITE_IOERR_DIR_FSYNC;
+      }
+      close(fd);
+    }
+  }
+  return rc;
+}
+
+/*
+** Test the existance of or access permissions of file zPath. The
+** test performed depends on the value of flags:
+**
+**     SQLITE_ACCESS_EXISTS: Return 1 if the file exists
+**     SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
+**     SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
+**
+** Otherwise return 0.
+*/
+static int unixAccess(sqlite3_vfs *pVfs, const char *zPath, int flags){
+  int amode = 0;
+  switch( flags ){
+    case SQLITE_ACCESS_EXISTS:
+      amode = F_OK;
+      break;
+    case SQLITE_ACCESS_READWRITE:
+      amode = W_OK|R_OK;
+      break;
+    case SQLITE_ACCESS_READ:
+      amode = R_OK;
+      break;
+
+    default:
+      assert(!"Invalid flags argument");
+  }
+  return (access(zPath, amode)==0);
+}
+
+/*
+** Create a temporary file name in zBuf.  zBuf must be allocated
+** by the calling process and must be big enough to hold at least
+** pVfs->mxPathname bytes.
+*/
+static int unixGetTempname(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+  static const char *azDirs[] = {
+     0,
+     "/var/tmp",
+     "/usr/tmp",
+     "/tmp",
+     ".",
+  };
+  static const unsigned char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  int i, j;
+  struct stat buf;
+  const char *zDir = ".";
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. 
+  */
+  SimulateIOError( return SQLITE_ERROR );
+
+  azDirs[0] = sqlite3_temp_directory;
+  for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); i++){
+    if( azDirs[i]==0 ) continue;
+    if( stat(azDirs[i], &buf) ) continue;
+    if( !S_ISDIR(buf.st_mode) ) continue;
+    if( access(azDirs[i], 07) ) continue;
+    zDir = azDirs[i];
+    break;
+  }
+
+  /* Check that the output buffer is large enough for the temporary file 
+  ** name. If it is not, return SQLITE_ERROR.
+  */
+  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 17) >= nBuf ){
+    return SQLITE_ERROR;
+  }
+
+  do{
+    assert( pVfs->mxPathname==MAX_PATHNAME );
+    sqlite3_snprintf(nBuf-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
+    j = strlen(zBuf);
+    sqlite3_randomness(15, &zBuf[j]);
+    for(i=0; i<15; i++, j++){
+      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
+    }
+    zBuf[j] = 0;
+  }while( access(zBuf,0)==0 );
+  return SQLITE_OK;
+}
+
+
+/*
+** Turn a relative pathname into a full pathname. The relative path
+** is stored as a nul-terminated string in the buffer pointed to by
+** zPath. 
+**
+** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes 
+** (in this case, MAX_PATHNAME bytes). The full-path is written to
+** this buffer before returning.
+*/
+static int unixFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zPath,            /* Possibly relative input path */
+  int nOut,                     /* Size of output buffer in bytes */
+  char *zOut                    /* Output buffer */
+){
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. This function could fail if, for example, the
+  ** current working directly has been unlinked.
+  */
+  SimulateIOError( return SQLITE_ERROR );
+
+  assert( pVfs->mxPathname==MAX_PATHNAME );
+  zOut[nOut-1] = '\0';
+  if( zPath[0]=='/' ){
+    sqlite3_snprintf(nOut, zOut, "%s", zPath);
+  }else{
+    int nCwd;
+    if( getcwd(zOut, nOut-1)==0 ){
+      return SQLITE_CANTOPEN;
+    }
+    nCwd = strlen(zOut);
+    sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath);
+  }
+  return SQLITE_OK;
+
+#if 0
+  /*
+  ** Remove "/./" path elements and convert "/A/./" path elements
+  ** to just "/".
+  */
+  if( zFull ){
+    int i, j;
+    for(i=j=0; zFull[i]; i++){
+      if( zFull[i]=='/' ){
+        if( zFull[i+1]=='/' ) continue;
+        if( zFull[i+1]=='.' && zFull[i+2]=='/' ){
+          i += 1;
+          continue;
+        }
+        if( zFull[i+1]=='.' && zFull[i+2]=='.' && zFull[i+3]=='/' ){
+          while( j>0 && zFull[j-1]!='/' ){ j--; }
+          i += 3;
+          continue;
+        }
+      }
+      zFull[j++] = zFull[i];
+    }
+    zFull[j] = 0;
+  }
+#endif
+}
+
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+#include <dlfcn.h>
+static void *unixDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
+  return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL);
+}
+
+/*
+** SQLite calls this function immediately after a call to unixDlSym() or
+** unixDlOpen() fails (returns a null pointer). If a more detailed error
+** message is available, it is written to zBufOut. If no error message
+** is available, zBufOut is left unmodified and SQLite uses a default
+** error message.
+*/
+static void unixDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
+  char *zErr;
+  enterMutex();
+  zErr = dlerror();
+  if( zErr ){
+    sqlite3_snprintf(nBuf, zBufOut, "%s", zErr);
+  }
+  leaveMutex();
+}
+static void *unixDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
+  return dlsym(pHandle, zSymbol);
+}
+static void unixDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  dlclose(pHandle);
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define unixDlOpen  0
+  #define unixDlError 0
+  #define unixDlSym   0
+  #define unixDlClose 0
+#endif
+
+/*
+** Write nBuf bytes of random data to the supplied buffer zBuf.
+*/
+static int unixRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+
+  assert(nBuf>=(sizeof(time_t)+sizeof(int)));
+
+  /* We have to initialize zBuf to prevent valgrind from reporting
+  ** errors.  The reports issued by valgrind are incorrect - we would
+  ** prefer that the randomness be increased by making use of the
+  ** uninitialized space in zBuf - but valgrind errors tend to worry
+  ** some users.  Rather than argue, it seems easier just to initialize
+  ** the whole array and silence valgrind, even if that means less randomness
+  ** in the random seed.
+  **
+  ** When testing, initializing zBuf[] to zero is all we do.  That means
+  ** that we always use the same random number sequence.  This makes the
+  ** tests repeatable.
+  */
+  memset(zBuf, 0, nBuf);
+#if !defined(SQLITE_TEST)
+  {
+    int pid, fd;
+    fd = open("/dev/urandom", O_RDONLY);
+    if( fd<0 ){
+      time_t t;
+      time(&t);
+      memcpy(zBuf, &t, sizeof(t));
+      pid = getpid();
+      memcpy(&zBuf[sizeof(t)], &pid, sizeof(pid));
+    }else{
+      read(fd, zBuf, nBuf);
+      close(fd);
+    }
+  }
+#endif
+  return SQLITE_OK;
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+** The argument is the number of microseconds we want to sleep.
+** The return value is the number of microseconds of sleep actually
+** requested from the underlying operating system, a number which
+** might be greater than or equal to the argument, but not less
+** than the argument.
+*/
+static int unixSleep(sqlite3_vfs *pVfs, int microseconds){
+#if defined(HAVE_USLEEP) && HAVE_USLEEP
+  usleep(microseconds);
+  return microseconds;
+#else
+  int seconds = (microseconds+999999)/1000000;
+  sleep(seconds);
+  return seconds*1000000;
+#endif
+}
+
+/*
+** The following variable, if set to a non-zero value, becomes the result
+** returned from sqlite3OsCurrentTime().  This is used for testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+static int unixCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+#ifdef NO_GETTOD
+  time_t t;
+  time(&t);
+  *prNow = t/86400.0 + 2440587.5;
+#else
+  struct timeval sNow;
+  gettimeofday(&sNow, 0);
+  *prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_usec/86400000000.0;
+#endif
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
+  }
+#endif
+  return 0;
+}
+
+/*
+** Return a pointer to the sqlite3DefaultVfs structure.   We use
+** a function rather than give the structure global scope because
+** some compilers (MSVC) do not allow forward declarations of
+** initialized structures.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3OsDefaultVfs(void){
+  static sqlite3_vfs unixVfs = {
+    1,                  /* iVersion */
+    sizeof(unixFile),   /* szOsFile */
+    MAX_PATHNAME,       /* mxPathname */
+    0,                  /* pNext */
+    "unix",             /* zName */
+    0,                  /* pAppData */
+  
+    unixOpen,           /* xOpen */
+    unixDelete,         /* xDelete */
+    unixAccess,         /* xAccess */
+    unixGetTempname,    /* xGetTempName */
+    unixFullPathname,   /* xFullPathname */
+    unixDlOpen,         /* xDlOpen */
+    unixDlError,        /* xDlError */
+    unixDlSym,          /* xDlSym */
+    unixDlClose,        /* xDlClose */
+    unixRandomness,     /* xRandomness */
+    unixSleep,          /* xSleep */
+    unixCurrentTime     /* xCurrentTime */
+  };
+  
+  return &unixVfs;
+}
+ 
+#endif /* OS_UNIX */
+
+/************** End of os_unix.c *********************************************/
+/************** Begin file os_win.c ******************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to windows.
+*/
+#if OS_WIN               /* This file is used for windows only */
+
+
+/*
+** A Note About Memory Allocation:
+**
+** This driver uses malloc()/free() directly rather than going through
+** the SQLite-wrappers sqlite3_malloc()/sqlite3_free().  Those wrappers
+** are designed for use on embedded systems where memory is scarce and
+** malloc failures happen frequently.  Win32 does not typically run on
+** embedded systems, and when it does the developers normally have bigger
+** problems to worry about than running out of memory.  So there is not
+** a compelling need to use the wrappers.
+**
+** But there is a good reason to not use the wrappers.  If we use the
+** wrappers then we will get simulated malloc() failures within this
+** driver.  And that causes all kinds of problems for our tests.  We
+** could enhance SQLite to deal with simulated malloc failures within
+** the OS driver, but the code to deal with those failure would not
+** be exercised on Linux (which does not need to malloc() in the driver)
+** and so we would have difficulty writing coverage tests for that
+** code.  Better to leave the code out, we think.
+**
+** The point of this discussion is as follows:  When creating a new
+** OS layer for an embedded system, if you use this file as an example,
+** avoid the use of malloc()/free().  Those routines work ok on windows
+** desktops but not so well in embedded systems.
+*/
+
+#include <qconfig.h>
+
+#include <winbase.h>
+
+#ifdef __CYGWIN__
+# include <sys/cygwin.h>
+#endif
+
+/*
+** Macros used to determine whether or not to use threads.
+*/
+#ifndef QT_NO_THREAD
+# define SQLITE_W32_THREADS 1
+#endif
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/************** Include os_common.h in the middle of os_win.c ****************/
+/************** Begin file os_common.h ***************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains macros and a little bit of code that is common to
+** all of the platform-specific files (os_*.c) and is #included into those
+** files.
+**
+** This file should be #included by the os_*.c files only.  It is not a
+** general purpose header file.
+*/
+
+/*
+** At least two bugs have slipped in because we changed the MEMORY_DEBUG
+** macro to SQLITE_DEBUG and some older makefiles have not yet made the
+** switch.  The following code should catch this problem at compile-time.
+*/
+#ifdef MEMORY_DEBUG
+# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
+#endif
+
+
+/*
+ * When testing, this global variable stores the location of the
+ * pending-byte in the database file.
+ */
+#ifdef SQLITE_TEST
+SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3OSTrace = 0;
+#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
+#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
+#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D) \
+    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
+#else
+#define OSTRACE1(X)
+#define OSTRACE2(X,Y)
+#define OSTRACE3(X,Y,Z)
+#define OSTRACE4(X,Y,Z,A)
+#define OSTRACE5(X,Y,Z,A,B)
+#define OSTRACE6(X,Y,Z,A,B,C)
+#define OSTRACE7(X,Y,Z,A,B,C,D)
+#endif
+
+/*
+** Macros for performance tracing.  Normally turned off.  Only works
+** on i486 hardware.
+*/
+#ifdef SQLITE_PERFORMANCE_TRACE
+__inline__ unsigned long long int hwtime(void){
+  unsigned long long int x;
+  __asm__("rdtsc\n\t"
+          "mov %%edx, %%ecx\n\t"
+          :"=A" (x));
+  return x;
+}
+static unsigned long long int g_start;
+static unsigned int elapse;
+#define TIMER_START       g_start=hwtime()
+#define TIMER_END         elapse=hwtime()-g_start
+#define TIMER_ELAPSED     elapse
+#else
+#define TIMER_START
+#define TIMER_END
+#define TIMER_ELAPSED     0
+#endif
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
+SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
+SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
+SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
+SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
+SQLITE_API int sqlite3_diskfull_pending = 0;
+SQLITE_API int sqlite3_diskfull = 0;
+#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
+#define SimulateIOError(CODE)  \
+  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
+       || sqlite3_io_error_pending-- == 1 )  \
+              { local_ioerr(); CODE; }
+static void local_ioerr(){
+  IOTRACE(("IOERR\n"));
+  sqlite3_io_error_hit++;
+  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
+}
+#define SimulateDiskfullError(CODE) \
+   if( sqlite3_diskfull_pending ){ \
+     if( sqlite3_diskfull_pending == 1 ){ \
+       local_ioerr(); \
+       sqlite3_diskfull = 1; \
+       sqlite3_io_error_hit = 1; \
+       CODE; \
+     }else{ \
+       sqlite3_diskfull_pending--; \
+     } \
+   }
+#else
+#define SimulateIOErrorBenign(X)
+#define SimulateIOError(A)
+#define SimulateDiskfullError(A)
+#endif
+
+/*
+** When testing, keep a count of the number of open files.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_open_file_count = 0;
+#define OpenCounter(X)  sqlite3_open_file_count+=(X)
+#else
+#define OpenCounter(X)
+#endif
+
+/************** End of os_common.h *******************************************/
+/************** Continuing where we left off in os_win.c *********************/
+
+/*
+** Determine if we are dealing with WindowsCE - which has a much
+** reduced API.
+*/
+#if defined(_WIN32_WCE)
+# define OS_WINCE 1
+# define AreFileApisANSI() 1
+#else
+# define OS_WINCE 0
+#endif
+
+/*
+** WinCE lacks native support for file locking so we have to fake it
+** with some code of our own.
+*/
+#if OS_WINCE
+typedef struct winceLock {
+  int nReaders;       /* Number of reader locks obtained */
+  BOOL bPending;      /* Indicates a pending lock has been obtained */
+  BOOL bReserved;     /* Indicates a reserved lock has been obtained */
+  BOOL bExclusive;    /* Indicates an exclusive lock has been obtained */
+} winceLock;
+#endif
+
+/*
+** The winFile structure is a subclass of sqlite3_file* specific to the win32
+** portability layer.
+*/
+typedef struct winFile winFile;
+struct winFile {
+  const sqlite3_io_methods *pMethod;/* Must be first */
+  HANDLE h;               /* Handle for accessing the file */
+  unsigned char locktype; /* Type of lock currently held on this file */
+  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
+#if OS_WINCE
+  WCHAR *zDeleteOnClose;  /* Name of file to delete when closing */
+  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
+  HANDLE hShared;         /* Shared memory segment used for locking */
+  winceLock local;        /* Locks obtained by this instance of winFile */
+  winceLock *shared;      /* Global shared lock memory for the file  */
+#endif
+};
+
+
+/*
+** The following variable is (normally) set once and never changes
+** thereafter.  It records whether the operating system is Win95
+** or WinNT.
+**
+** 0:   Operating system unknown.
+** 1:   Operating system is Win95.
+** 2:   Operating system is WinNT.
+**
+** In order to facilitate testing on a WinNT system, the test fixture
+** can manually set this value to 1 to emulate Win98 behavior.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_os_type = 0;
+#else
+static int sqlite3_os_type = 0;
+#endif
+
+/*
+** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
+** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
+**
+** Here is an interesting observation:  Win95, Win98, and WinME lack
+** the LockFileEx() API.  But we can still statically link against that
+** API as long as we don't call it win running Win95/98/ME.  A call to
+** this routine is used to determine if the host is Win95/98/ME or
+** WinNT/2K/XP so that we will know whether or not we can safely call
+** the LockFileEx() API.
+*/
+#if OS_WINCE
+# define isNT()  (1)
+#else
+  static int isNT(void){
+    if( sqlite3_os_type==0 ){
+      OSVERSIONINFO sInfo;
+      sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+      GetVersionEx(&sInfo);
+      sqlite3_os_type = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
+    }
+    return sqlite3_os_type==2;
+  }
+#endif /* OS_WINCE */
+
+/*
+** Convert a UTF-8 string to microsoft unicode (UTF-16?). 
+**
+** Space to hold the returned string is obtained from malloc.
+*/
+static WCHAR *utf8ToUnicode(const char *zFilename){
+  int nChar;
+  WCHAR *zWideFilename;
+
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
+  zWideFilename = malloc( nChar*sizeof(zWideFilename[0]) );
+  if( zWideFilename==0 ){
+    return 0;
+  }
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename, nChar);
+  if( nChar==0 ){
+    free(zWideFilename);
+    zWideFilename = 0;
+  }
+  return zWideFilename;
+}
+
+/*
+** Convert microsoft unicode to UTF-8.  Space to hold the returned string is
+** obtained from malloc().
+*/
+static char *unicodeToUtf8(const WCHAR *zWideFilename){
+  int nByte;
+  char *zFilename;
+
+  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
+  zFilename = malloc( nByte );
+  if( zFilename==0 ){
+    return 0;
+  }
+  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
+                              0, 0);
+  if( nByte == 0 ){
+    free(zFilename);
+    zFilename = 0;
+  }
+  return zFilename;
+}
+
+/*
+** Convert an ansi string to microsoft unicode, based on the
+** current codepage settings for file apis.
+** 
+** Space to hold the returned string is obtained
+** from malloc.
+*/
+static WCHAR *mbcsToUnicode(const char *zFilename){
+  int nByte;
+  WCHAR *zMbcsFilename;
+  int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+
+  nByte = MultiByteToWideChar(codepage, 0, zFilename, -1, NULL,0)*sizeof(WCHAR);
+  zMbcsFilename = malloc( nByte*sizeof(zMbcsFilename[0]) );
+  if( zMbcsFilename==0 ){
+    return 0;
+  }
+  nByte = MultiByteToWideChar(codepage, 0, zFilename, -1, zMbcsFilename, nByte);
+  if( nByte==0 ){
+    free(zMbcsFilename);
+    zMbcsFilename = 0;
+  }
+  return zMbcsFilename;
+}
+
+/*
+** Convert microsoft unicode to multibyte character string, based on the
+** user's Ansi codepage.
+**
+** Space to hold the returned string is obtained from
+** malloc().
+*/
+static char *unicodeToMbcs(const WCHAR *zWideFilename){
+  int nByte;
+  char *zFilename;
+  int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+
+  nByte = WideCharToMultiByte(codepage, 0, zWideFilename, -1, 0, 0, 0, 0);
+  zFilename = malloc( nByte );
+  if( zFilename==0 ){
+    return 0;
+  }
+  nByte = WideCharToMultiByte(codepage, 0, zWideFilename, -1, zFilename, nByte,
+                              0, 0);
+  if( nByte == 0 ){
+    free(zFilename);
+    zFilename = 0;
+  }
+  return zFilename;
+}
+
+/*
+** Convert multibyte character string to UTF-8.  Space to hold the
+** returned string is obtained from malloc().
+*/
+static char *mbcsToUtf8(const char *zFilename){
+  char *zFilenameUtf8;
+  WCHAR *zTmpWide;
+
+  zTmpWide = mbcsToUnicode(zFilename);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zFilenameUtf8 = unicodeToUtf8(zTmpWide);
+  free(zTmpWide);
+  return zFilenameUtf8;
+}
+
+/*
+** Convert UTF-8 to multibyte character string.  Space to hold the 
+** returned string is obtained from malloc().
+*/
+static char *utf8ToMbcs(const char *zFilename){
+  char *zFilenameMbcs;
+  WCHAR *zTmpWide;
+
+  zTmpWide = utf8ToUnicode(zFilename);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zFilenameMbcs = unicodeToMbcs(zTmpWide);
+  free(zTmpWide);
+  return zFilenameMbcs;
+}
+
+#if OS_WINCE
+/*************************************************************************
+** This section contains code for WinCE only.
+*/
+/*
+** WindowsCE does not have a localtime() function.  So create a
+** substitute.
+*/
+static struct tm *__cdecl localtime(const time_t *t)
+{
+  static struct tm y;
+  FILETIME uTm, lTm;
+  SYSTEMTIME pTm;
+  sqlite3_int64 t64;
+  t64 = *t;
+  t64 = (t64 + 11644473600)*10000000;
+  uTm.dwLowDateTime = t64 & 0xFFFFFFFF;
+  uTm.dwHighDateTime= t64 >> 32;
+  FileTimeToLocalFileTime(&uTm,&lTm);
+  FileTimeToSystemTime(&lTm,&pTm);
+  y.tm_year = pTm.wYear - 1900;
+  y.tm_mon = pTm.wMonth - 1;
+  y.tm_wday = pTm.wDayOfWeek;
+  y.tm_mday = pTm.wDay;
+  y.tm_hour = pTm.wHour;
+  y.tm_min = pTm.wMinute;
+  y.tm_sec = pTm.wSecond;
+  return &y;
+}
+
+/* This will never be called, but defined to make the code compile */
+#define GetTempPathA(a,b)
+
+#define LockFile(a,b,c,d,e)       winceLockFile(&a, b, c, d, e)
+#define UnlockFile(a,b,c,d,e)     winceUnlockFile(&a, b, c, d, e)
+#define LockFileEx(a,b,c,d,e,f)   winceLockFileEx(&a, b, c, d, e, f)
+
+#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-offsetof(winFile,h)]
+
+/*
+** Acquire a lock on the handle h
+*/
+static void winceMutexAcquire(HANDLE h){
+   DWORD dwErr;
+   do {
+     dwErr = WaitForSingleObject(h, INFINITE);
+   } while (dwErr != WAIT_OBJECT_0 && dwErr != WAIT_ABANDONED);
+}
+/*
+** Release a lock acquired by winceMutexAcquire()
+*/
+#define winceMutexRelease(h) ReleaseMutex(h)
+
+/*
+** Create the mutex and shared memory used for locking in the file
+** descriptor pFile
+*/
+static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
+  WCHAR *zTok;
+  WCHAR *zName = utf8ToUnicode(zFilename);
+  BOOL bInit = TRUE;
+
+  /* Initialize the local lockdata */
+  ZeroMemory(&pFile->local, sizeof(pFile->local));
+
+  /* Replace the backslashes from the filename and lowercase it
+  ** to derive a mutex name. */
+  zTok = CharLowerW(zName);
+  for (;*zTok;zTok++){
+    if (*zTok == '\\') *zTok = '_';
+  }
+
+  /* Create/open the named mutex */
+  pFile->hMutex = CreateMutexW(NULL, FALSE, zName);
+  if (!pFile->hMutex){
+    free(zName);
+    return FALSE;
+  }
+
+  /* Acquire the mutex before continuing */
+  winceMutexAcquire(pFile->hMutex);
+  
+  /* Since the names of named mutexes, semaphores, file mappings etc are 
+  ** case-sensitive, take advantage of that by uppercasing the mutex name
+  ** and using that as the shared filemapping name.
+  */
+  CharUpperW(zName);
+  pFile->hShared = CreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
+                                       PAGE_READWRITE, 0, sizeof(winceLock),
+                                       zName);  
+
+  /* Set a flag that indicates we're the first to create the memory so it 
+  ** must be zero-initialized */
+  if (GetLastError() == ERROR_ALREADY_EXISTS){
+    bInit = FALSE;
+  }
+
+  free(zName);
+
+  /* If we succeeded in making the shared memory handle, map it. */
+  if (pFile->hShared){
+    pFile->shared = (winceLock*)MapViewOfFile(pFile->hShared, 
+             FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
+    /* If mapping failed, close the shared memory handle and erase it */
+    if (!pFile->shared){
+      CloseHandle(pFile->hShared);
+      pFile->hShared = NULL;
+    }
+  }
+
+  /* If shared memory could not be created, then close the mutex and fail */
+  if (pFile->hShared == NULL){
+    winceMutexRelease(pFile->hMutex);
+    CloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+    return FALSE;
+  }
+  
+  /* Initialize the shared memory if we're supposed to */
+  if (bInit) {
+    ZeroMemory(pFile->shared, sizeof(winceLock));
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return TRUE;
+}
+
+/*
+** Destroy the part of winFile that deals with wince locks
+*/
+static void winceDestroyLock(winFile *pFile){
+  if (pFile->hMutex){
+    /* Acquire the mutex */
+    winceMutexAcquire(pFile->hMutex);
+
+    /* The following blocks should probably assert in debug mode, but they
+       are to cleanup in case any locks remained open */
+    if (pFile->local.nReaders){
+      pFile->shared->nReaders --;
+    }
+    if (pFile->local.bReserved){
+      pFile->shared->bReserved = FALSE;
+    }
+    if (pFile->local.bPending){
+      pFile->shared->bPending = FALSE;
+    }
+    if (pFile->local.bExclusive){
+      pFile->shared->bExclusive = FALSE;
+    }
+
+    /* De-reference and close our copy of the shared memory handle */
+    UnmapViewOfFile(pFile->shared);
+    CloseHandle(pFile->hShared);
+
+    /* Done with the mutex */
+    winceMutexRelease(pFile->hMutex);    
+    CloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+  }
+}
+
+/* 
+** An implementation of the LockFile() API of windows for wince
+*/
+static BOOL winceLockFile(
+  HANDLE *phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToLockLow,
+  DWORD nNumberOfBytesToLockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Wanting an exclusive lock? */
+  if (dwFileOffsetLow == SHARED_FIRST
+       && nNumberOfBytesToLockLow == SHARED_SIZE){
+    if (pFile->shared->nReaders == 0 && pFile->shared->bExclusive == 0){
+       pFile->shared->bExclusive = TRUE;
+       pFile->local.bExclusive = TRUE;
+       bReturn = TRUE;
+    }
+  }
+
+  /* Want a read-only lock? */
+  else if ((dwFileOffsetLow >= SHARED_FIRST &&
+            dwFileOffsetLow < SHARED_FIRST + SHARED_SIZE) &&
+            nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bExclusive == 0){
+      pFile->local.nReaders ++;
+      if (pFile->local.nReaders == 1){
+        pFile->shared->nReaders ++;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Want a pending lock? */
+  else if (dwFileOffsetLow == PENDING_BYTE && nNumberOfBytesToLockLow == 1){
+    /* If no pending lock has been acquired, then acquire it */
+    if (pFile->shared->bPending == 0) {
+      pFile->shared->bPending = TRUE;
+      pFile->local.bPending = TRUE;
+      bReturn = TRUE;
+    }
+  }
+  /* Want a reserved lock? */
+  else if (dwFileOffsetLow == RESERVED_BYTE && nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bReserved == 0) {
+      pFile->shared->bReserved = TRUE;
+      pFile->local.bReserved = TRUE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+
+/*
+** An implementation of the UnlockFile API of windows for wince
+*/
+static BOOL winceUnlockFile(
+  HANDLE *phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToUnlockLow,
+  DWORD nNumberOfBytesToUnlockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Releasing a reader lock or an exclusive lock */
+  if (dwFileOffsetLow >= SHARED_FIRST &&
+       dwFileOffsetLow < SHARED_FIRST + SHARED_SIZE){
+    /* Did we have an exclusive lock? */
+    if (pFile->local.bExclusive){
+      pFile->local.bExclusive = FALSE;
+      pFile->shared->bExclusive = FALSE;
+      bReturn = TRUE;
+    }
+
+    /* Did we just have a reader lock? */
+    else if (pFile->local.nReaders){
+      pFile->local.nReaders --;
+      if (pFile->local.nReaders == 0)
+      {
+        pFile->shared->nReaders --;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Releasing a pending lock */
+  else if (dwFileOffsetLow == PENDING_BYTE && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bPending){
+      pFile->local.bPending = FALSE;
+      pFile->shared->bPending = FALSE;
+      bReturn = TRUE;
+    }
+  }
+  /* Releasing a reserved lock */
+  else if (dwFileOffsetLow == RESERVED_BYTE && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bReserved) {
+      pFile->local.bReserved = FALSE;
+      pFile->shared->bReserved = FALSE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+
+/*
+** An implementation of the LockFileEx() API of windows for wince
+*/
+static BOOL winceLockFileEx(
+  HANDLE *phFile,
+  DWORD dwFlags,
+  DWORD dwReserved,
+  DWORD nNumberOfBytesToLockLow,
+  DWORD nNumberOfBytesToLockHigh,
+  LPOVERLAPPED lpOverlapped
+){
+  /* If the caller wants a shared read lock, forward this call
+  ** to winceLockFile */
+  if (lpOverlapped->Offset == SHARED_FIRST &&
+      dwFlags == 1 &&
+      nNumberOfBytesToLockLow == SHARED_SIZE){
+    return winceLockFile(phFile, SHARED_FIRST, 0, 1, 0);
+  }
+  return FALSE;
+}
+/*
+** End of the special code for wince
+*****************************************************************************/
+#endif /* OS_WINCE */
+
+/*****************************************************************************
+** The next group of routines implement the I/O methods specified
+** by the sqlite3_io_methods object.
+******************************************************************************/
+
+/*
+** Close a file.
+**
+** It is reported that an attempt to close a handle might sometimes
+** fail.  This is a very unreasonable result, but windows is notorious
+** for being unreasonable so I do not doubt that it might happen.  If
+** the close fails, we pause for 100 milliseconds and try again.  As
+** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
+** giving up and returning an error.
+*/
+#define MX_CLOSE_ATTEMPT 3
+static int winClose(sqlite3_file *id){
+  int rc, cnt = 0;
+  winFile *pFile = (winFile*)id;
+  OSTRACE2("CLOSE %d\n", pFile->h);
+  do{
+    rc = CloseHandle(pFile->h);
+  }while( rc==0 && cnt++ < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
+#if OS_WINCE
+#define WINCE_DELETION_ATTEMPTS 3
+  winceDestroyLock(pFile);
+  if( pFile->zDeleteOnClose ){
+    int cnt = 0;
+    while(
+           DeleteFileW(pFile->zDeleteOnClose)==0
+        && GetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff 
+        && cnt++ < WINCE_DELETION_ATTEMPTS
+    ){
+       Sleep(100);  /* Wait a little before trying again */
+    }
+    free(pFile->zDeleteOnClose);
+  }
+#endif
+  OpenCounter(-1);
+  return rc ? SQLITE_OK : SQLITE_IOERR;
+}
+
+/*
+** Some microsoft compilers lack this definition.
+*/
+#ifndef INVALID_SET_FILE_POINTER
+# define INVALID_SET_FILE_POINTER ((DWORD)-1)
+#endif
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int winRead(
+  sqlite3_file *id,          /* File to read from */
+  void *pBuf,                /* Write content into this buffer */
+  int amt,                   /* Number of bytes to read */
+  sqlite3_int64 offset       /* Begin reading at this offset */
+){
+  LONG upperBits = (offset>>32) & 0x7fffffff;
+  LONG lowerBits = offset & 0xffffffff;
+  DWORD rc;
+  DWORD got;
+  winFile *pFile = (winFile*)id;
+  assert( id!=0 );
+  SimulateIOError(return SQLITE_IOERR_READ);
+  OSTRACE3("READ %d lock=%d\n", pFile->h, pFile->locktype);
+  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
+    return SQLITE_FULL;
+  }
+  if( !ReadFile(pFile->h, pBuf, amt, &got, 0) ){
+    return SQLITE_IOERR_READ;
+  }
+  if( got==(DWORD)amt ){
+    return SQLITE_OK;
+  }else{
+    memset(&((char*)pBuf)[got], 0, amt-got);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+}
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int winWrite(
+  sqlite3_file *id,         /* File to write into */
+  const void *pBuf,         /* The bytes to be written */
+  int amt,                  /* Number of bytes to write */
+  sqlite3_int64 offset      /* Offset into the file to begin writing at */
+){
+  LONG upperBits = (offset>>32) & 0x7fffffff;
+  LONG lowerBits = offset & 0xffffffff;
+  DWORD rc;
+  DWORD wrote;
+  winFile *pFile = (winFile*)id;
+  assert( id!=0 );
+  SimulateIOError(return SQLITE_IOERR_WRITE);
+  SimulateDiskfullError(return SQLITE_FULL);
+  OSTRACE3("WRITE %d lock=%d\n", pFile->h, pFile->locktype);
+  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
+    return SQLITE_FULL;
+  }
+  assert( amt>0 );
+  while(
+     amt>0
+     && (rc = WriteFile(pFile->h, pBuf, amt, &wrote, 0))!=0
+     && wrote>0
+  ){
+    amt -= wrote;
+    pBuf = &((char*)pBuf)[wrote];
+  }
+  if( !rc || amt>(int)wrote ){
+    return SQLITE_FULL;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
+  LONG upperBits = (nByte>>32) & 0x7fffffff;
+  LONG lowerBits = nByte & 0xffffffff;
+  winFile *pFile = (winFile*)id;
+  OSTRACE3("TRUNCATE %d %lld\n", pFile->h, nByte);
+  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
+  SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+  SetEndOfFile(pFile->h);
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occuring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+*/
+static int winSync(sqlite3_file *id, int flags){
+  winFile *pFile = (winFile*)id;
+  OSTRACE3("SYNC %d lock=%d\n", pFile->h, pFile->locktype);
+#ifdef SQLITE_TEST
+  if( flags & SQLITE_SYNC_FULL ){
+    sqlite3_fullsync_count++;
+  }
+  sqlite3_sync_count++;
+#endif
+  if( FlushFileBuffers(pFile->h) ){
+    return SQLITE_OK;
+  }else{
+    return SQLITE_IOERR;
+  }
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
+  winFile *pFile = (winFile*)id;
+  DWORD upperBits, lowerBits;
+  SimulateIOError(return SQLITE_IOERR_FSTAT);
+  lowerBits = GetFileSize(pFile->h, &upperBits);
+  *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
+  return SQLITE_OK;
+}
+
+/*
+** LOCKFILE_FAIL_IMMEDIATELY is undefined on some Windows systems.
+*/
+#ifndef LOCKFILE_FAIL_IMMEDIATELY
+# define LOCKFILE_FAIL_IMMEDIATELY 1
+#endif
+
+/*
+** Acquire a reader lock.
+** Different API routines are called depending on whether or not this
+** is Win95 or WinNT.
+*/
+static int getReadLock(winFile *pFile){
+  int res;
+  if( isNT() ){
+    OVERLAPPED ovlp;
+    ovlp.Offset = SHARED_FIRST;
+    ovlp.OffsetHigh = 0;
+    ovlp.hEvent = 0;
+    res = LockFileEx(pFile->h, LOCKFILE_FAIL_IMMEDIATELY,
+                     0, SHARED_SIZE, 0, &ovlp);
+  }else{
+    int lk;
+    sqlite3_randomness(sizeof(lk), &lk);
+    pFile->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
+    res = LockFile(pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
+  return res;
+}
+
+/*
+** Undo a readlock
+*/
+static int unlockReadLock(winFile *pFile){
+  int res;
+  if( isNT() ){
+    res = UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+  }else{
+    res = UnlockFile(pFile->h, SHARED_FIRST + pFile->sharedLockByte, 0, 1, 0);
+  }
+  return res;
+}
+
+/*
+** Lock the file with the lock specified by parameter locktype - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  The winUnlock() routine
+** erases all locks at once and returns us immediately to locking level 0.
+** It is not possible to lower the locking level one step at a time.  You
+** must go straight to locking level 0.
+*/
+static int winLock(sqlite3_file *id, int locktype){
+  int rc = SQLITE_OK;    /* Return code from subroutines */
+  int res = 1;           /* Result of a windows lock call */
+  int newLocktype;       /* Set pFile->locktype to this value before exiting */
+  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
+  winFile *pFile = (winFile*)id;
+
+  assert( pFile!=0 );
+  OSTRACE5("LOCK %d %d was %d(%d)\n",
+          pFile->h, locktype, pFile->locktype, pFile->sharedLockByte);
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** OsFile, do nothing. Don't use the end_lock: exit path, as
+  ** sqlite3OsEnterMutex() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
+  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
+  ** the PENDING_LOCK byte is temporary.
+  */
+  newLocktype = pFile->locktype;
+  if( pFile->locktype==NO_LOCK
+   || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
+  ){
+    int cnt = 3;
+    while( cnt-->0 && (res = LockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
+      /* Try 3 times to get the pending lock.  The pending lock might be
+      ** held by another reader process who will release it momentarily.
+      */
+      OSTRACE2("could not get a PENDING lock. cnt=%d\n", cnt);
+      Sleep(1);
+    }
+    gotPendingLock = res;
+  }
+
+  /* Acquire a shared lock
+  */
+  if( locktype==SHARED_LOCK && res ){
+    assert( pFile->locktype==NO_LOCK );
+    res = getReadLock(pFile);
+    if( res ){
+      newLocktype = SHARED_LOCK;
+    }
+  }
+
+  /* Acquire a RESERVED lock
+  */
+  if( locktype==RESERVED_LOCK && res ){
+    assert( pFile->locktype==SHARED_LOCK );
+    res = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    if( res ){
+      newLocktype = RESERVED_LOCK;
+    }
+  }
+
+  /* Acquire a PENDING lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    newLocktype = PENDING_LOCK;
+    gotPendingLock = 0;
+  }
+
+  /* Acquire an EXCLUSIVE lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    assert( pFile->locktype>=SHARED_LOCK );
+    res = unlockReadLock(pFile);
+    OSTRACE2("unreadlock = %d\n", res);
+    res = LockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    if( res ){
+      newLocktype = EXCLUSIVE_LOCK;
+    }else{
+      OSTRACE2("error-code = %d\n", GetLastError());
+      getReadLock(pFile);
+    }
+  }
+
+  /* If we are holding a PENDING lock that ought to be released, then
+  ** release it now.
+  */
+  if( gotPendingLock && locktype==SHARED_LOCK ){
+    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+
+  /* Update the state of the lock has held in the file descriptor then
+  ** return the appropriate result code.
+  */
+  if( res ){
+    rc = SQLITE_OK;
+  }else{
+    OSTRACE4("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
+           locktype, newLocktype);
+    rc = SQLITE_BUSY;
+  }
+  pFile->locktype = newLocktype;
+  return rc;
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, return
+** non-zero, otherwise zero.
+*/
+static int winCheckReservedLock(sqlite3_file *id){
+  int rc;
+  winFile *pFile = (winFile*)id;
+  assert( pFile!=0 );
+  if( pFile->locktype>=RESERVED_LOCK ){
+    rc = 1;
+    OSTRACE3("TEST WR-LOCK %d %d (local)\n", pFile->h, rc);
+  }else{
+    rc = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    if( rc ){
+      UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    }
+    rc = !rc;
+    OSTRACE3("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc);
+  }
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor id to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** It is not possible for this routine to fail if the second argument
+** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
+** might return SQLITE_IOERR;
+*/
+static int winUnlock(sqlite3_file *id, int locktype){
+  int type;
+  winFile *pFile = (winFile*)id;
+  int rc = SQLITE_OK;
+  assert( pFile!=0 );
+  assert( locktype<=SHARED_LOCK );
+  OSTRACE5("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
+          pFile->locktype, pFile->sharedLockByte);
+  type = pFile->locktype;
+  if( type>=EXCLUSIVE_LOCK ){
+    UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
+      /* This should never happen.  We should always be able to
+      ** reacquire the read lock */
+      rc = SQLITE_IOERR_UNLOCK;
+    }
+  }
+  if( type>=RESERVED_LOCK ){
+    UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+  }
+  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
+    unlockReadLock(pFile);
+  }
+  if( type>=PENDING_LOCK ){
+    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+  pFile->locktype = locktype;
+  return rc;
+}
+
+/*
+** Control and query of the open file handle.
+*/
+static int winFileControl(sqlite3_file *id, int op, void *pArg){
+  switch( op ){
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = ((winFile*)id)->locktype;
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int winSectorSize(sqlite3_file *id){
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+/*
+** Return a vector of device characteristics.
+*/
+static int winDeviceCharacteristics(sqlite3_file *id){
+  return 0;
+}
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32.
+*/
+static const sqlite3_io_methods winIoMethod = {
+  1,                        /* iVersion */
+  winClose,
+  winRead,
+  winWrite,
+  winTruncate,
+  winSync,
+  winFileSize,
+  winLock,
+  winUnlock,
+  winCheckReservedLock,
+  winFileControl,
+  winSectorSize,
+  winDeviceCharacteristics
+};
+
+/***************************************************************************
+** Here ends the I/O methods that form the sqlite3_io_methods object.
+**
+** The next block of code implements the VFS methods.
+****************************************************************************/
+
+/*
+** Convert a UTF-8 filename into whatever form the underlying
+** operating system wants filenames in.  Space to hold the result
+** is obtained from malloc and must be freed by the calling
+** function.
+*/
+static void *convertUtf8Filename(const char *zFilename){
+  void *zConverted = 0;
+  if( isNT() ){
+    zConverted = utf8ToUnicode(zFilename);
+  }else{
+    zConverted = utf8ToMbcs(zFilename);
+  }
+  /* caller will handle out of memory */
+  return zConverted;
+}
+
+/*
+** Open a file.
+*/
+static int winOpen(
+  sqlite3_vfs *pVfs,        /* Not used */
+  const char *zName,        /* Name of the file (UTF-8) */
+  sqlite3_file *id,         /* Write the SQLite file handle here */
+  int flags,                /* Open mode flags */
+  int *pOutFlags            /* Status return flags */
+){
+  HANDLE h;
+  DWORD dwDesiredAccess;
+  DWORD dwShareMode;
+  DWORD dwCreationDisposition;
+  DWORD dwFlagsAndAttributes = 0;
+  int isTemp;
+  winFile *pFile = (winFile*)id;
+  void *zConverted = convertUtf8Filename(zName);
+  if( zConverted==0 ){
+    return SQLITE_NOMEM;
+  }
+
+  if( flags & SQLITE_OPEN_READWRITE ){
+    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
+  }else{
+    dwDesiredAccess = GENERIC_READ;
+  }
+  if( flags & SQLITE_OPEN_CREATE ){
+    dwCreationDisposition = OPEN_ALWAYS;
+  }else{
+    dwCreationDisposition = OPEN_EXISTING;
+  }
+  if( flags & SQLITE_OPEN_MAIN_DB ){
+    dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+  }else{
+    dwShareMode = 0;
+  }
+  if( flags & SQLITE_OPEN_DELETEONCLOSE ){
+#if OS_WINCE
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_HIDDEN;
+#else
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_TEMPORARY
+                               | FILE_ATTRIBUTE_HIDDEN
+                               | FILE_FLAG_DELETE_ON_CLOSE;
+#endif
+    isTemp = 1;
+  }else{
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
+    isTemp = 0;
+  }
+  /* Reports from the internet are that performance is always
+  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
+  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
+  if( isNT() ){
+    h = CreateFileW((WCHAR*)zConverted,
+       dwDesiredAccess,
+       dwShareMode,
+       NULL,
+       dwCreationDisposition,
+       dwFlagsAndAttributes,
+       NULL
+    );
+  }else{
+#if OS_WINCE
+    return SQLITE_NOMEM;
+#else
+    h = CreateFileA((char*)zConverted,
+       dwDesiredAccess,
+       dwShareMode,
+       NULL,
+       dwCreationDisposition,
+       dwFlagsAndAttributes,
+       NULL
+    );
+#endif
+  }
+  if( h==INVALID_HANDLE_VALUE ){
+    free(zConverted);
+    if( flags & SQLITE_OPEN_READWRITE ){
+      return winOpen(0, zName, id, 
+             ((flags|SQLITE_OPEN_READONLY)&~SQLITE_OPEN_READWRITE), pOutFlags);
+    }else{
+      return SQLITE_CANTOPEN;
+    }
+  }
+  if( pOutFlags ){
+    if( flags & SQLITE_OPEN_READWRITE ){
+      *pOutFlags = SQLITE_OPEN_READWRITE;
+    }else{
+      *pOutFlags = SQLITE_OPEN_READONLY;
+    }
+  }
+  memset(pFile, 0, sizeof(*pFile));
+  pFile->pMethod = &winIoMethod;
+  pFile->h = h;
+#if OS_WINCE
+  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
+               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
+       && !winceCreateLock(zName, pFile)
+  ){
+    CloseHandle(h);
+    free(zConverted);
+    return SQLITE_CANTOPEN;
+  }
+  if( isTemp ){
+    pFile->zDeleteOnClose = zConverted;
+  }else
+#endif
+  {
+    free(zConverted);
+  }
+  OpenCounter(+1);
+  return SQLITE_OK;
+}
+
+/*
+** Delete the named file.
+**
+** Note that windows does not allow a file to be deleted if some other
+** process has it open.  Sometimes a virus scanner or indexing program
+** will open a journal file shortly after it is created in order to do
+** whatever does.  While this other process is holding the
+** file open, we will be unable to delete it.  To work around this
+** problem, we delay 100 milliseconds and try to delete again.  Up
+** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
+** up and returning an error.
+*/
+#define MX_DELETION_ATTEMPTS 5
+static int winDelete(
+  sqlite3_vfs *pVfs,          /* Not used on win32 */
+  const char *zFilename,      /* Name of file to delete */
+  int syncDir                 /* Not used on win32 */
+){
+  int cnt = 0;
+  int rc;
+  void *zConverted = convertUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    return SQLITE_NOMEM;
+  }
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  if( isNT() ){
+    do{
+      DeleteFileW(zConverted);
+    }while( (rc = GetFileAttributesW(zConverted))!=0xffffffff 
+            && cnt++ < MX_DELETION_ATTEMPTS && (Sleep(100), 1) );
+  }else{
+#if OS_WINCE
+    return SQLITE_NOMEM;
+#else
+    do{
+      DeleteFileA(zConverted);
+    }while( (rc = GetFileAttributesA(zConverted))!=0xffffffff
+            && cnt++ < MX_DELETION_ATTEMPTS && (Sleep(100), 1) );
+#endif
+  }
+  free(zConverted);
+  OSTRACE2("DELETE \"%s\"\n", zFilename);
+  return rc==0xffffffff ? SQLITE_OK : SQLITE_IOERR_DELETE;
+}
+
+/*
+** Check the existance and status of a file.
+*/
+static int winAccess(
+  sqlite3_vfs *pVfs,         /* Not used on win32 */
+  const char *zFilename,     /* Name of file to check */
+  int flags                  /* Type of test to make on this file */
+){
+  DWORD attr;
+  int rc;
+  void *zConverted = convertUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    return SQLITE_NOMEM;
+  }
+  if( isNT() ){
+    attr = GetFileAttributesW((WCHAR*)zConverted);
+  }else{
+#if OS_WINCE
+    return SQLITE_NOMEM;
+#else
+    attr = GetFileAttributesA((char*)zConverted);
+#endif
+  }
+  free(zConverted);
+  switch( flags ){
+    case SQLITE_ACCESS_READ:
+    case SQLITE_ACCESS_EXISTS:
+      rc = attr!=0xffffffff;
+      break;
+    case SQLITE_ACCESS_READWRITE:
+      rc = (attr & FILE_ATTRIBUTE_READONLY)==0;
+      break;
+    default:
+      assert(!"Invalid flags argument");
+  }
+  return rc;
+}
+
+
+/*
+** Create a temporary file name in zBuf.  zBuf must be big enough to
+** hold at pVfs->mxPathname characters.
+*/
+static int winGetTempname(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+  static char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  int i, j;
+  char zTempPath[MAX_PATH+1];
+  if( sqlite3_temp_directory ){
+    sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", sqlite3_temp_directory);
+  }else if( isNT() ){
+    char *zMulti;
+    WCHAR zWidePath[MAX_PATH];
+    GetTempPathW(MAX_PATH-30, zWidePath);
+    zMulti = unicodeToUtf8(zWidePath);
+    if( zMulti ){
+      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zMulti);
+      free(zMulti);
+    }else{
+      return SQLITE_NOMEM;
+    }
+  }else{
+    char *zUtf8;
+    char zMbcsPath[MAX_PATH];
+    GetTempPathA(MAX_PATH-30, zMbcsPath);
+    zUtf8 = mbcsToUtf8(zMbcsPath);
+    if( zUtf8 ){
+      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zUtf8);
+      free(zUtf8);
+    }else{
+      return SQLITE_NOMEM;
+    }
+  }
+  for(i=strlen(zTempPath); i>0 && zTempPath[i-1]=='\\'; i--){}
+  zTempPath[i] = 0;
+  sqlite3_snprintf(nBuf-30, zBuf,
+                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
+  j = strlen(zBuf);
+  sqlite3_randomness(20, &zBuf[j]);
+  for(i=0; i<20; i++, j++){
+    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
+  }
+  zBuf[j] = 0;
+  OSTRACE2("TEMP FILENAME: %s\n", zBuf);
+  return SQLITE_OK; 
+}
+
+/*
+** Turn a relative pathname into a full pathname.  Write the full
+** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
+** bytes in size.
+*/
+static int winFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+
+#if defined(__CYGWIN__)
+  cygwin_conv_to_full_win32_path(zRelative, zFull);
+  return SQLITE_OK;
+#endif
+
+#if OS_WINCE
+  /* WinCE has no concept of a relative pathname, or so I am told. */
+  sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zRelative);
+  return SQLITE_OK;
+#endif
+
+#if !OS_WINCE && !defined(__CYGWIN__)
+  int nByte;
+  void *zConverted;
+  char *zOut;
+  zConverted = convertUtf8Filename(zRelative);
+  if( isNT() ){
+    WCHAR *zTemp;
+    nByte = GetFullPathNameW((WCHAR*)zConverted, 0, 0, 0) + 3;
+    zTemp = malloc( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      free(zConverted);
+      return SQLITE_NOMEM;
+    }
+    GetFullPathNameW((WCHAR*)zConverted, nByte, zTemp, 0);
+    free(zConverted);
+    zOut = unicodeToUtf8(zTemp);
+    free(zTemp);
+  }else{
+    char *zTemp;
+    nByte = GetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
+    zTemp = malloc( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      free(zConverted);
+      return SQLITE_NOMEM;
+    }
+    GetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
+    free(zConverted);
+    zOut = mbcsToUtf8(zTemp);
+    free(zTemp);
+  }
+  if( zOut ){
+    sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zOut);
+    free(zOut);
+    return SQLITE_OK;
+  }else{
+    return SQLITE_NOMEM;
+  }
+#endif
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
+  HANDLE h;
+  void *zConverted = convertUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    return 0;
+  }
+  if( isNT() ){
+    h = LoadLibraryW((WCHAR*)zConverted);
+  }else{
+#if OS_WINCE
+    return 0;
+#else
+    h = LoadLibraryA((char*)zConverted);
+#endif
+  }
+  free(zConverted);
+  return (void*)h;
+}
+static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
+#if OS_WINCE
+  int error = GetLastError();
+  if( error>0x7FFFFFF ){
+    sqlite3_snprintf(nBuf, zBufOut, "OsError 0x%x", error);
+  }else{
+    sqlite3_snprintf(nBuf, zBufOut, "OsError %d", error);
+  }
+#else
+  FormatMessageA(
+    FORMAT_MESSAGE_FROM_SYSTEM,
+    NULL,
+    GetLastError(),
+    0,
+    zBufOut,
+    nBuf-1,
+    0
+  );
+#endif
+}
+void *winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
+#if OS_WINCE
+  /* The GetProcAddressA() routine is only available on wince. */
+  return GetProcAddressA((HANDLE)pHandle, zSymbol);
+#else
+  /* All other windows platforms expect GetProcAddress() to take
+  ** an Ansi string regardless of the _UNICODE setting */
+  return GetProcAddress((HANDLE)pHandle, zSymbol);
+#endif
+}
+void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  FreeLibrary((HANDLE)pHandle);
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define winDlOpen  0
+  #define winDlError 0
+  #define winDlSym   0
+  #define winDlClose 0
+#endif
+
+
+/*
+** Write up to nBuf bytes of randomness into zBuf.
+*/
+static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+  int n = 0;
+  if( sizeof(SYSTEMTIME)<=nBuf-n ){
+    SYSTEMTIME x;
+    GetSystemTime(&x);
+    memcpy(&zBuf[n], &x, sizeof(x));
+    n += sizeof(x);
+  }
+  if( sizeof(DWORD)<=nBuf-n ){
+    DWORD pid = GetCurrentProcessId();
+    memcpy(&zBuf[n], &pid, sizeof(pid));
+    n += sizeof(pid);
+  }
+  if( sizeof(DWORD)<=nBuf-n ){
+    DWORD cnt = GetTickCount();
+    memcpy(&zBuf[n], &cnt, sizeof(cnt));
+    n += sizeof(cnt);
+  }
+  if( sizeof(LARGE_INTEGER)<=nBuf-n ){
+    LARGE_INTEGER i;
+    QueryPerformanceCounter(&i);
+    memcpy(&zBuf[n], &i, sizeof(i));
+    n += sizeof(i);
+  }
+  return n;
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+static int winSleep(sqlite3_vfs *pVfs, int microsec){
+  Sleep((microsec+999)/1000);
+  return ((microsec+999)/1000)*1000;
+}
+
+/*
+** The following variable, if set to a non-zero value, becomes the result
+** returned from sqlite3OsCurrentTime().  This is used for testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+  FILETIME ft;
+  /* FILETIME structure is a 64-bit value representing the number of 
+     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). 
+  */
+  double now;
+#if OS_WINCE
+  SYSTEMTIME time;
+  GetSystemTime(&time);
+  SystemTimeToFileTime(&time,&ft);
+#else
+  GetSystemTimeAsFileTime( &ft );
+#endif
+  now = ((double)ft.dwHighDateTime) * 4294967296.0; 
+  *prNow = (now + ft.dwLowDateTime)/864000000000.0 + 2305813.5;
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
+  }
+#endif
+  return 0;
+}
+
+
+/*
+** Return a pointer to the sqlite3DefaultVfs structure.   We use
+** a function rather than give the structure global scope because
+** some compilers (MSVC) do not allow forward declarations of
+** initialized structures.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3OsDefaultVfs(void){
+  static sqlite3_vfs winVfs = {
+    1,                 /* iVersion */
+    sizeof(winFile),   /* szOsFile */
+    MAX_PATH,          /* mxPathname */
+    0,                 /* pNext */
+    "win32",           /* zName */
+    0,                 /* pAppData */
+  
+    winOpen,           /* xOpen */
+    winDelete,         /* xDelete */
+    winAccess,         /* xAccess */
+    winGetTempname,    /* xGetTempName */
+    winFullPathname,   /* xFullPathname */
+    winDlOpen,         /* xDlOpen */
+    winDlError,        /* xDlError */
+    winDlSym,          /* xDlSym */
+    winDlClose,        /* xDlClose */
+    winRandomness,     /* xRandomness */
+    winSleep,          /* xSleep */
+    winCurrentTime     /* xCurrentTime */
+  };
+  
+  return &winVfs;
+}
+
+#endif /* OS_WIN */
+
+/************** End of os_win.c **********************************************/
+/************** Begin file bitvec.c ******************************************/
+/*
+** 2008 February 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an object that represents a fixed-length
+** bitmap.  Bits are numbered starting with 1.
+**
+** A bitmap is used to record what pages a database file have been
+** journalled during a transaction.  Usually only a few pages are
+** journalled.  So the bitmap is usually sparse and has low cardinality.
+** But sometimes (for example when during a DROP of a large table) most
+** or all of the pages get journalled.  In those cases, the bitmap becomes
+** dense.  The algorithm needs to handle both cases well.
+**
+** The size of the bitmap is fixed when the object is created.
+**
+** All bits are clear when the bitmap is created.  Individual bits
+** may be set or cleared one at a time.
+**
+** Test operations are about 100 times more common that set operations.
+** Clear operations are exceedingly rare.  There are usually between
+** 5 and 500 set operations per Bitvec object, though the number of sets can
+** sometimes grow into tens of thousands or larger.  The size of the
+** Bitvec object is the number of pages in the database file at the
+** start of a transaction, and is thus usually less than a few thousand,
+** but can be as large as 2 billion for a really big database.
+**
+** @(#) $Id: bitvec.c,v 1.5 2008/05/13 13:27:34 drh Exp $
+*/
+
+#define BITVEC_SZ        512
+/* Round the union size down to the nearest pointer boundary, since that's how 
+** it will be aligned within the Bitvec struct. */
+#define BITVEC_USIZE     (((BITVEC_SZ-12)/sizeof(Bitvec*))*sizeof(Bitvec*))
+#define BITVEC_NCHAR     BITVEC_USIZE
+#define BITVEC_NBIT      (BITVEC_NCHAR*8)
+#define BITVEC_NINT      (BITVEC_USIZE/4)
+#define BITVEC_MXHASH    (BITVEC_NINT/2)
+#define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))
+
+#define BITVEC_HASH(X)   (((X)*37)%BITVEC_NINT)
+
+/*
+** A bitmap is an instance of the following structure.
+**
+** This bitmap records the existance of zero or more bits
+** with values between 1 and iSize, inclusive.
+**
+** There are three possible representations of the bitmap.
+** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
+** bitmap.  The least significant bit is bit 1.
+**
+** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is
+** a hash table that will hold up to BITVEC_MXHASH distinct values.
+**
+** Otherwise, the value i is redirected into one of BITVEC_NPTR
+** sub-bitmaps pointed to by Bitvec.u.apSub[].  Each subbitmap
+** handles up to iDivisor separate values of i.  apSub[0] holds
+** values between 1 and iDivisor.  apSub[1] holds values between
+** iDivisor+1 and 2*iDivisor.  apSub[N] holds values between
+** N*iDivisor+1 and (N+1)*iDivisor.  Each subbitmap is normalized
+** to hold deal with values between 1 and iDivisor.
+*/
+struct Bitvec {
+  u32 iSize;      /* Maximum bit index */
+  u32 nSet;       /* Number of bits that are set */
+  u32 iDivisor;   /* Number of bits handled by each apSub[] entry */
+  union {
+    u8 aBitmap[BITVEC_NCHAR];    /* Bitmap representation */
+    u32 aHash[BITVEC_NINT];      /* Hash table representation */
+    Bitvec *apSub[BITVEC_NPTR];  /* Recursive representation */
+  } u;
+};
+
+/*
+** Create a new bitmap object able to handle bits between 0 and iSize,
+** inclusive.  Return a pointer to the new object.  Return NULL if 
+** malloc fails.
+*/
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32 iSize){
+  Bitvec *p;
+  assert( sizeof(*p)==BITVEC_SZ );
+  p = sqlite3MallocZero( sizeof(*p) );
+  if( p ){
+    p->iSize = iSize;
+  }
+  return p;
+}
+
+/*
+** Check to see if the i-th bit is set.  Return true or false.
+** If p is NULL (if the bitmap has not been created) or if
+** i is out of range, then return false.
+*/
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
+  if( p==0 ) return 0;
+  if( i>p->iSize || i==0 ) return 0;
+  if( p->iSize<=BITVEC_NBIT ){
+    i--;
+    return (p->u.aBitmap[i/8] & (1<<(i&7)))!=0;
+  }
+  if( p->iDivisor>0 ){
+    u32 bin = (i-1)/p->iDivisor;
+    i = (i-1)%p->iDivisor + 1;
+    return sqlite3BitvecTest(p->u.apSub[bin], i);
+  }else{
+    u32 h = BITVEC_HASH(i);
+    while( p->u.aHash[h] ){
+      if( p->u.aHash[h]==i ) return 1;
+      h++;
+      if( h>=BITVEC_NINT ) h = 0;
+    }
+    return 0;
+  }
+}
+
+/*
+** Set the i-th bit.  Return 0 on success and an error code if
+** anything goes wrong.
+*/
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec *p, u32 i){
+  u32 h;
+  assert( p!=0 );
+  assert( i>0 );
+  assert( i<=p->iSize );
+  if( p->iSize<=BITVEC_NBIT ){
+    i--;
+    p->u.aBitmap[i/8] |= 1 << (i&7);
+    return SQLITE_OK;
+  }
+  if( p->iDivisor ){
+    u32 bin = (i-1)/p->iDivisor;
+    i = (i-1)%p->iDivisor + 1;
+    if( p->u.apSub[bin]==0 ){
+      sqlite3FaultBeginBenign(SQLITE_FAULTINJECTOR_MALLOC);
+      p->u.apSub[bin] = sqlite3BitvecCreate( p->iDivisor );
+      sqlite3FaultEndBenign(SQLITE_FAULTINJECTOR_MALLOC);
+      if( p->u.apSub[bin]==0 ) return SQLITE_NOMEM;
+    }
+    return sqlite3BitvecSet(p->u.apSub[bin], i);
+  }
+  h = BITVEC_HASH(i);
+  while( p->u.aHash[h] ){
+    if( p->u.aHash[h]==i ) return SQLITE_OK;
+    h++;
+    if( h==BITVEC_NINT ) h = 0;
+  }
+  p->nSet++;
+  if( p->nSet>=BITVEC_MXHASH ){
+    int j, rc;
+    u32 aiValues[BITVEC_NINT];
+    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
+    memset(p->u.apSub, 0, sizeof(p->u.apSub[0])*BITVEC_NPTR);
+    p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
+    rc = sqlite3BitvecSet(p, i);
+    for(j=0; j<BITVEC_NINT; j++){
+      if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
+    }
+    return rc;
+  }
+  p->u.aHash[h] = i;
+  return SQLITE_OK;
+}
+
+/*
+** Clear the i-th bit.  Return 0 on success and an error code if
+** anything goes wrong.
+*/
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i){
+  assert( p!=0 );
+  assert( i>0 );
+  if( p->iSize<=BITVEC_NBIT ){
+    i--;
+    p->u.aBitmap[i/8] &= ~(1 << (i&7));
+  }else if( p->iDivisor ){
+    u32 bin = (i-1)/p->iDivisor;
+    i = (i-1)%p->iDivisor + 1;
+    if( p->u.apSub[bin] ){
+      sqlite3BitvecClear(p->u.apSub[bin], i);
+    }
+  }else{
+    int j;
+    u32 aiValues[BITVEC_NINT];
+    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
+    memset(p->u.aHash, 0, sizeof(p->u.aHash[0])*BITVEC_NINT);
+    p->nSet = 0;
+    for(j=0; j<BITVEC_NINT; j++){
+      if( aiValues[j] && aiValues[j]!=i ){
+        sqlite3BitvecSet(p, aiValues[j]);
+      }
+    }
+  }
+}
+
+/*
+** Destroy a bitmap object.  Reclaim all memory used.
+*/
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec *p){
+  if( p==0 ) return;
+  if( p->iDivisor ){
+    int i;
+    for(i=0; i<BITVEC_NPTR; i++){
+      sqlite3BitvecDestroy(p->u.apSub[i]);
+    }
+  }
+  sqlite3_free(p);
+}
+
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+/*
+** Let V[] be an array of unsigned characters sufficient to hold
+** up to N bits.  Let I be an integer between 0 and N.  0<=I<N.
+** Then the following macros can be used to set, clear, or test
+** individual bits within V.
+*/
+#define SETBIT(V,I)      V[I>>3] |= (1<<(I&7))
+#define CLEARBIT(V,I)    V[I>>3] &= ~(1<<(I&7))
+#define TESTBIT(V,I)     (V[I>>3]&(1<<(I&7)))!=0
+
+/*
+** This routine runs an extensive test of the Bitvec code.
+**
+** The input is an array of integers that acts as a program
+** to test the Bitvec.  The integers are opcodes followed
+** by 0, 1, or 3 operands, depending on the opcode.  Another
+** opcode follows immediately after the last operand.
+**
+** There are 6 opcodes numbered from 0 through 5.  0 is the
+** "halt" opcode and causes the test to end.
+**
+**    0          Halt and return the number of errors
+**    1 N S X    Set N bits beginning with S and incrementing by X
+**    2 N S X    Clear N bits beginning with S and incrementing by X
+**    3 N        Set N randomly chosen bits
+**    4 N        Clear N randomly chosen bits
+**    5 N S X    Set N bits from S increment X in array only, not in bitvec
+**
+** The opcodes 1 through 4 perform set and clear operations are performed
+** on both a Bitvec object and on a linear array of bits obtained from malloc.
+** Opcode 5 works on the linear array only, not on the Bitvec.
+** Opcode 5 is used to deliberately induce a fault in order to
+** confirm that error detection works.
+**
+** At the conclusion of the test the linear array is compared
+** against the Bitvec object.  If there are any differences,
+** an error is returned.  If they are the same, zero is returned.
+**
+** If a memory allocation error occurs, return -1.
+*/
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
+  Bitvec *pBitvec = 0;
+  unsigned char *pV = 0;
+  int rc = -1;
+  int i, nx, pc, op;
+
+  /* Allocate the Bitvec to be tested and a linear array of
+  ** bits to act as the reference */
+  pBitvec = sqlite3BitvecCreate( sz );
+  pV = sqlite3_malloc( (sz+7)/8 + 1 );
+  if( pBitvec==0 || pV==0 ) goto bitvec_end;
+  memset(pV, 0, (sz+7)/8 + 1);
+
+  /* Run the program */
+  pc = 0;
+  while( (op = aOp[pc])!=0 ){
+    switch( op ){
+      case 1:
+      case 2:
+      case 5: {
+        nx = 4;
+        i = aOp[pc+2] - 1;
+        aOp[pc+2] += aOp[pc+3];
+        break;
+      }
+      case 3:
+      case 4: 
+      default: {
+        nx = 2;
+        sqlite3_randomness(sizeof(i), &i);
+        break;
+      }
+    }
+    if( (--aOp[pc+1]) > 0 ) nx = 0;
+    pc += nx;
+    i = (i & 0x7fffffff)%sz;
+    if( (op & 1)!=0 ){
+      SETBIT(pV, (i+1));
+      if( op!=5 ){
+        if( sqlite3BitvecSet(pBitvec, i+1) ) goto bitvec_end;
+      }
+    }else{
+      CLEARBIT(pV, (i+1));
+      sqlite3BitvecClear(pBitvec, i+1);
+    }
+  }
+
+  /* Test to make sure the linear array exactly matches the
+  ** Bitvec object.  Start with the assumption that they do
+  ** match (rc==0).  Change rc to non-zero if a discrepancy
+  ** is found.
+  */
+  rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
+          + sqlite3BitvecTest(pBitvec, 0);
+  for(i=1; i<=sz; i++){
+    if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
+      rc = i;
+      break;
+    }
+  }
+
+  /* Free allocated structure */
+bitvec_end:
+  sqlite3_free(pV);
+  sqlite3BitvecDestroy(pBitvec);
+  return rc;
+}
+#endif /* SQLITE_OMIT_BUILTIN_TEST */
+
+/************** End of bitvec.c **********************************************/
+/************** Begin file pager.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of the page cache subsystem or "pager".
+** 
+** The pager is used to access a database disk file.  It implements
+** atomic commit and rollback through the use of a journal file that
+** is separate from the database file.  The pager also implements file
+** locking to prevent two processes from writing the same database
+** file simultaneously, or one process from reading the database while
+** another is writing.
+**
+** @(#) $Id: pager.c,v 1.446 2008/05/13 13:27:34 drh Exp $
+*/
+#ifndef SQLITE_OMIT_DISKIO
+
+/*
+** Macros for troubleshooting.  Normally turned off
+*/
+#if 0
+#define sqlite3DebugPrintf printf
+#define PAGERTRACE1(X)       sqlite3DebugPrintf(X)
+#define PAGERTRACE2(X,Y)     sqlite3DebugPrintf(X,Y)
+#define PAGERTRACE3(X,Y,Z)   sqlite3DebugPrintf(X,Y,Z)
+#define PAGERTRACE4(X,Y,Z,W) sqlite3DebugPrintf(X,Y,Z,W)
+#define PAGERTRACE5(X,Y,Z,W,V) sqlite3DebugPrintf(X,Y,Z,W,V)
+#else
+#define PAGERTRACE1(X)
+#define PAGERTRACE2(X,Y)
+#define PAGERTRACE3(X,Y,Z)
+#define PAGERTRACE4(X,Y,Z,W)
+#define PAGERTRACE5(X,Y,Z,W,V)
+#endif
+
+/*
+** The following two macros are used within the PAGERTRACEX() macros above
+** to print out file-descriptors. 
+**
+** PAGERID() takes a pointer to a Pager struct as its argument. The
+** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file
+** struct as its argument.
+*/
+#define PAGERID(p) ((int)(p->fd))
+#define FILEHANDLEID(fd) ((int)fd)
+
+/*
+** The page cache as a whole is always in one of the following
+** states:
+**
+**   PAGER_UNLOCK        The page cache is not currently reading or 
+**                       writing the database file.  There is no
+**                       data held in memory.  This is the initial
+**                       state.
+**
+**   PAGER_SHARED        The page cache is reading the database.
+**                       Writing is not permitted.  There can be
+**                       multiple readers accessing the same database
+**                       file at the same time.
+**
+**   PAGER_RESERVED      This process has reserved the database for writing
+**                       but has not yet made any changes.  Only one process
+**                       at a time can reserve the database.  The original
+**                       database file has not been modified so other
+**                       processes may still be reading the on-disk
+**                       database file.
+**
+**   PAGER_EXCLUSIVE     The page cache is writing the database.
+**                       Access is exclusive.  No other processes or
+**                       threads can be reading or writing while one
+**                       process is writing.
+**
+**   PAGER_SYNCED        The pager moves to this state from PAGER_EXCLUSIVE
+**                       after all dirty pages have been written to the
+**                       database file and the file has been synced to
+**                       disk. All that remains to do is to remove or
+**                       truncate the journal file and the transaction 
+**                       will be committed.
+**
+** The page cache comes up in PAGER_UNLOCK.  The first time a
+** sqlite3PagerGet() occurs, the state transitions to PAGER_SHARED.
+** After all pages have been released using sqlite_page_unref(),
+** the state transitions back to PAGER_UNLOCK.  The first time
+** that sqlite3PagerWrite() is called, the state transitions to
+** PAGER_RESERVED.  (Note that sqlite3PagerWrite() can only be
+** called on an outstanding page which means that the pager must
+** be in PAGER_SHARED before it transitions to PAGER_RESERVED.)
+** PAGER_RESERVED means that there is an open rollback journal.
+** The transition to PAGER_EXCLUSIVE occurs before any changes
+** are made to the database file, though writes to the rollback
+** journal occurs with just PAGER_RESERVED.  After an sqlite3PagerRollback()
+** or sqlite3PagerCommitPhaseTwo(), the state can go back to PAGER_SHARED,
+** or it can stay at PAGER_EXCLUSIVE if we are in exclusive access mode.
+*/
+#define PAGER_UNLOCK      0
+#define PAGER_SHARED      1   /* same as SHARED_LOCK */
+#define PAGER_RESERVED    2   /* same as RESERVED_LOCK */
+#define PAGER_EXCLUSIVE   4   /* same as EXCLUSIVE_LOCK */
+#define PAGER_SYNCED      5
+
+/*
+** If the SQLITE_BUSY_RESERVED_LOCK macro is set to true at compile-time,
+** then failed attempts to get a reserved lock will invoke the busy callback.
+** This is off by default.  To see why, consider the following scenario:
+** 
+** Suppose thread A already has a shared lock and wants a reserved lock.
+** Thread B already has a reserved lock and wants an exclusive lock.  If
+** both threads are using their busy callbacks, it might be a long time
+** be for one of the threads give up and allows the other to proceed.
+** But if the thread trying to get the reserved lock gives up quickly
+** (if it never invokes its busy callback) then the contention will be
+** resolved quickly.
+*/
+#ifndef SQLITE_BUSY_RESERVED_LOCK
+# define SQLITE_BUSY_RESERVED_LOCK 0
+#endif
+
+/*
+** This macro rounds values up so that if the value is an address it
+** is guaranteed to be an address that is aligned to an 8-byte boundary.
+*/
+#define FORCE_ALIGNMENT(X)   (((X)+7)&~7)
+
+typedef struct PgHdr PgHdr;
+
+/*
+** Each pager stores all currently unreferenced pages in a list sorted
+** in least-recently-used (LRU) order (i.e. the first item on the list has 
+** not been referenced in a long time, the last item has been recently
+** used). An instance of this structure is included as part of each
+** pager structure for this purpose (variable Pager.lru).
+**
+** Additionally, if memory-management is enabled, all unreferenced pages 
+** are stored in a global LRU list (global variable sqlite3LruPageList).
+**
+** In both cases, the PagerLruList.pFirstSynced variable points to
+** the first page in the corresponding list that does not require an
+** fsync() operation before its memory can be reclaimed. If no such
+** page exists, PagerLruList.pFirstSynced is set to NULL.
+*/
+typedef struct PagerLruList PagerLruList;
+struct PagerLruList {
+  PgHdr *pFirst;         /* First page in LRU list */
+  PgHdr *pLast;          /* Last page in LRU list (the most recently used) */
+  PgHdr *pFirstSynced;   /* First page in list with PgHdr.needSync==0 */
+};
+
+/*
+** The following structure contains the next and previous pointers used
+** to link a PgHdr structure into a PagerLruList linked list. 
+*/
+typedef struct PagerLruLink PagerLruLink;
+struct PagerLruLink {
+  PgHdr *pNext;
+  PgHdr *pPrev;
+};
+
+/*
+** Each in-memory image of a page begins with the following header.
+** This header is only visible to this pager module.  The client
+** code that calls pager sees only the data that follows the header.
+**
+** Client code should call sqlite3PagerWrite() on a page prior to making
+** any modifications to that page.  The first time sqlite3PagerWrite()
+** is called, the original page contents are written into the rollback
+** journal and PgHdr.inJournal and PgHdr.needSync are set.  Later, once
+** the journal page has made it onto the disk surface, PgHdr.needSync
+** is cleared.  The modified page cannot be written back into the original
+** database file until the journal pages has been synced to disk and the
+** PgHdr.needSync has been cleared.
+**
+** The PgHdr.dirty flag is set when sqlite3PagerWrite() is called and
+** is cleared again when the page content is written back to the original
+** database file.
+**
+** Details of important structure elements:
+**
+** needSync
+**
+**     If this is true, this means that it is not safe to write the page
+**     content to the database because the original content needed
+**     for rollback has not by synced to the main rollback journal.
+**     The original content may have been written to the rollback journal
+**     but it has not yet been synced.  So we cannot write to the database
+**     file because power failure might cause the page in the journal file
+**     to never reach the disk.  It is as if the write to the journal file
+**     does not occur until the journal file is synced.
+**     
+**     This flag is false if the page content exactly matches what
+**     currently exists in the database file.  The needSync flag is also
+**     false if the original content has been written to the main rollback
+**     journal and synced.  If the page represents a new page that has
+**     been added onto the end of the database during the current
+**     transaction, the needSync flag is true until the original database
+**     size in the journal header has been synced to disk.
+**
+** inJournal
+**
+**     This is true if the original page has been written into the main
+**     rollback journal.  This is always false for new pages added to
+**     the end of the database file during the current transaction.
+**     And this flag says nothing about whether or not the journal
+**     has been synced to disk.  For pages that are in the original
+**     database file, the following expression should always be true:
+**
+**       inJournal = sqlite3BitvecTest(pPager->pInJournal, pgno)
+**
+**     The pPager->pInJournal object is only valid for the original
+**     pages of the database, not new pages that are added to the end
+**     of the database, so obviously the above expression cannot be
+**     valid for new pages.  For new pages inJournal is always 0.
+**
+** dirty
+**
+**     When true, this means that the content of the page has been
+**     modified and needs to be written back to the database file.
+**     If false, it means that either the content of the page is
+**     unchanged or else the content is unimportant and we do not
+**     care whether or not it is preserved.
+**
+** alwaysRollback
+**
+**     This means that the sqlite3PagerDontRollback() API should be
+**     ignored for this page.  The DontRollback() API attempts to say
+**     that the content of the page on disk is unimportant (it is an
+**     unused page on the freelist) so that it is unnecessary to 
+**     rollback changes to this page because the content of the page
+**     can change without changing the meaning of the database.  This
+**     flag overrides any DontRollback() attempt.  This flag is set
+**     when a page that originally contained valid data is added to
+**     the freelist.  Later in the same transaction, this page might
+**     be pulled from the freelist and reused for something different
+**     and at that point the DontRollback() API will be called because
+**     pages taken from the freelist do not need to be protected by
+**     the rollback journal.  But this flag says that the page was
+**     not originally part of the freelist so that it still needs to
+**     be rolled back in spite of any subsequent DontRollback() calls.
+**
+** needRead 
+**
+**     This flag means (when true) that the content of the page has
+**     not yet been loaded from disk.  The in-memory content is just
+**     garbage.  (Actually, we zero the content, but you should not
+**     make any assumptions about the content nevertheless.)  If the
+**     content is needed in the future, it should be read from the
+**     original database file.
+*/
+struct PgHdr {
+  Pager *pPager;                 /* The pager to which this page belongs */
+  Pgno pgno;                     /* The page number for this page */
+  PgHdr *pNextHash, *pPrevHash;  /* Hash collision chain for PgHdr.pgno */
+  PagerLruLink free;             /* Next and previous free pages */
+  PgHdr *pNextAll;               /* A list of all pages */
+  u8 inJournal;                  /* TRUE if has been written to journal */
+  u8 dirty;                      /* TRUE if we need to write back changes */
+  u8 needSync;                   /* Sync journal before writing this page */
+  u8 alwaysRollback;             /* Disable DontRollback() for this page */
+  u8 needRead;                   /* Read content if PagerWrite() is called */
+  short int nRef;                /* Number of users of this page */
+  PgHdr *pDirty, *pPrevDirty;    /* Dirty pages */
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  PagerLruLink gfree;            /* Global list of nRef==0 pages */
+#endif
+#ifdef SQLITE_CHECK_PAGES
+  u32 pageHash;
+#endif
+  void *pData;                   /* Page data */
+  /* Pager.nExtra bytes of local data appended to this header */
+};
+
+/*
+** For an in-memory only database, some extra information is recorded about
+** each page so that changes can be rolled back.  (Journal files are not
+** used for in-memory databases.)  The following information is added to
+** the end of every EXTRA block for in-memory databases.
+**
+** This information could have been added directly to the PgHdr structure.
+** But then it would take up an extra 8 bytes of storage on every PgHdr
+** even for disk-based databases.  Splitting it out saves 8 bytes.  This
+** is only a savings of 0.8% but those percentages add up.
+*/
+typedef struct PgHistory PgHistory;
+struct PgHistory {
+  u8 *pOrig;     /* Original page text.  Restore to this on a full rollback */
+  u8 *pStmt;     /* Text as it was at the beginning of the current statement */
+  PgHdr *pNextStmt, *pPrevStmt;  /* List of pages in the statement journal */
+  u8 inStmt;                     /* TRUE if in the statement subjournal */
+};
+
+/*
+** A macro used for invoking the codec if there is one
+*/
+#ifdef SQLITE_HAS_CODEC
+# define CODEC1(P,D,N,X) if( P->xCodec!=0 ){ P->xCodec(P->pCodecArg,D,N,X); }
+# define CODEC2(P,D,N,X) ((char*)(P->xCodec!=0?P->xCodec(P->pCodecArg,D,N,X):D))
+#else
+# define CODEC1(P,D,N,X) /* NO-OP */
+# define CODEC2(P,D,N,X) ((char*)D)
+#endif
+
+/*
+** Convert a pointer to a PgHdr into a pointer to its data
+** and back again.
+*/
+#define PGHDR_TO_DATA(P)    ((P)->pData)
+#define PGHDR_TO_EXTRA(G,P) ((void*)&((G)[1]))
+#define PGHDR_TO_HIST(P,PGR)  \
+            ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->nExtra])
+
+/*
+** A open page cache is an instance of the following structure.
+**
+** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
+** or SQLITE_FULL. Once one of the first three errors occurs, it persists
+** and is returned as the result of every major pager API call.  The
+** SQLITE_FULL return code is slightly different. It persists only until the
+** next successful rollback is performed on the pager cache. Also,
+** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
+** APIs, they may still be used successfully.
+*/
+struct Pager {
+  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
+  u8 journalOpen;             /* True if journal file descriptors is valid */
+  u8 journalStarted;          /* True if header of journal is synced */
+  u8 useJournal;              /* Use a rollback journal on this file */
+  u8 noReadlock;              /* Do not bother to obtain readlocks */
+  u8 stmtOpen;                /* True if the statement subjournal is open */
+  u8 stmtInUse;               /* True we are in a statement subtransaction */
+  u8 stmtAutoopen;            /* Open stmt journal when main journal is opened*/
+  u8 noSync;                  /* Do not sync the journal if true */
+  u8 fullSync;                /* Do extra syncs of the journal for robustness */
+  u8 sync_flags;              /* One of SYNC_NORMAL or SYNC_FULL */
+  u8 state;                   /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
+  u8 tempFile;                /* zFilename is a temporary file */
+  u8 readOnly;                /* True for a read-only database */
+  u8 needSync;                /* True if an fsync() is needed on the journal */
+  u8 dirtyCache;              /* True if cached pages have changed */
+  u8 alwaysRollback;          /* Disable DontRollback() for all pages */
+  u8 memDb;                   /* True to inhibit all file I/O */
+  u8 setMaster;               /* True if a m-j name has been written to jrnl */
+  u8 doNotSync;               /* Boolean. While true, do not spill the cache */
+  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
+  u8 journalMode;             /* On of the PAGER_JOURNALMODE_* values */
+  u8 dbModified;              /* True if there are any changes to the Db */
+  u8 changeCountDone;         /* Set after incrementing the change-counter */
+  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
+  int errCode;                /* One of several kinds of errors */
+  int dbSize;                 /* Number of pages in the file */
+  int origDbSize;             /* dbSize before the current change */
+  int stmtSize;               /* Size of database (in pages) at stmt_begin() */
+  int nRec;                   /* Number of pages written to the journal */
+  u32 cksumInit;              /* Quasi-random value added to every checksum */
+  int stmtNRec;               /* Number of records in stmt subjournal */
+  int nExtra;                 /* Add this many bytes to each in-memory page */
+  int pageSize;               /* Number of bytes in a page */
+  int nPage;                  /* Total number of in-memory pages */
+  int nRef;                   /* Number of in-memory pages with PgHdr.nRef>0 */
+  int mxPage;                 /* Maximum number of pages to hold in cache */
+  Pgno mxPgno;                /* Maximum allowed size of the database */
+  Bitvec *pInJournal;         /* One bit for each page in the database file */
+  Bitvec *pInStmt;            /* One bit for each page in the database */
+  char *zFilename;            /* Name of the database file */
+  char *zJournal;             /* Name of the journal file */
+  char *zDirectory;           /* Directory hold database and journal files */
+  char *zStmtJrnl;            /* Name of the statement journal file */
+  sqlite3_file *fd, *jfd;     /* File descriptors for database and journal */
+  sqlite3_file *stfd;         /* File descriptor for the statement subjournal*/
+  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
+  PagerLruList lru;           /* LRU list of free pages */
+  PgHdr *pAll;                /* List of all pages */
+  PgHdr *pStmt;               /* List of pages in the statement subjournal */
+  PgHdr *pDirty;              /* List of all dirty pages */
+  i64 journalOff;             /* Current byte offset in the journal file */
+  i64 journalHdr;             /* Byte offset to previous journal header */
+  i64 stmtHdrOff;             /* First journal header written this statement */
+  i64 stmtCksum;              /* cksumInit when statement was started */
+  i64 stmtJSize;              /* Size of journal at stmt_begin() */
+  int sectorSize;             /* Assumed sector size during rollback */
+#ifdef SQLITE_TEST
+  int nHit, nMiss;            /* Cache hits and missing */
+  int nRead, nWrite;          /* Database pages read/written */
+#endif
+  void (*xDestructor)(DbPage*,int); /* Call this routine when freeing pages */
+  void (*xReiniter)(DbPage*,int);   /* Call this routine when reloading pages */
+#ifdef SQLITE_HAS_CODEC
+  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
+  void *pCodecArg;            /* First argument to xCodec() */
+#endif
+  int nHash;                  /* Size of the pager hash table */
+  PgHdr **aHash;              /* Hash table to map page number to PgHdr */
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  Pager *pNext;               /* Doubly linked list of pagers on which */
+  Pager *pPrev;               /* sqlite3_release_memory() will work */
+  int iInUseMM;               /* Non-zero if unavailable to MM */
+  int iInUseDB;               /* Non-zero if in sqlite3_release_memory() */
+#endif
+  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
+  char dbFileVers[16];        /* Changes whenever database file changes */
+};
+
+/*
+** The following global variables hold counters used for
+** testing purposes only.  These variables do not exist in
+** a non-testing build.  These variables are not thread-safe.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_pager_readdb_count = 0;    /* Number of full pages read from DB */
+SQLITE_API int sqlite3_pager_writedb_count = 0;   /* Number of full pages written to DB */
+SQLITE_API int sqlite3_pager_writej_count = 0;    /* Number of pages written to journal */
+SQLITE_API int sqlite3_pager_pgfree_count = 0;    /* Number of cache pages freed */
+# define PAGER_INCR(v)  v++
+#else
+# define PAGER_INCR(v)
+#endif
+
+/*
+** The following variable points to the head of a double-linked list
+** of all pagers that are eligible for page stealing by the
+** sqlite3_release_memory() interface.  Access to this list is
+** protected by the SQLITE_MUTEX_STATIC_MEM2 mutex.
+*/
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+static Pager *sqlite3PagerList = 0;
+static PagerLruList sqlite3LruPageList = {0, 0, 0};
+#endif
+
+
+/*
+** Journal files begin with the following magic string.  The data
+** was obtained from /dev/random.  It is used only as a sanity check.
+**
+** Since version 2.8.0, the journal format contains additional sanity
+** checking information.  If the power fails while the journal is begin
+** written, semi-random garbage data might appear in the journal
+** file after power is restored.  If an attempt is then made
+** to roll the journal back, the database could be corrupted.  The additional
+** sanity checking data is an attempt to discover the garbage in the
+** journal and ignore it.
+**
+** The sanity checking information for the new journal format consists
+** of a 32-bit checksum on each page of data.  The checksum covers both
+** the page number and the pPager->pageSize bytes of data for the page.
+** This cksum is initialized to a 32-bit random value that appears in the
+** journal file right after the header.  The random initializer is important,
+** because garbage data that appears at the end of a journal is likely
+** data that was once in other files that have now been deleted.  If the
+** garbage data came from an obsolete journal file, the checksums might
+** be correct.  But by initializing the checksum to random value which
+** is different for every journal, we minimize that risk.
+*/
+static const unsigned char aJournalMagic[] = {
+  0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
+};
+
+/*
+** The size of the header and of each page in the journal is determined
+** by the following macros.
+*/
+#define JOURNAL_PG_SZ(pPager)  ((pPager->pageSize) + 8)
+
+/*
+** The journal header size for this pager. In the future, this could be
+** set to some value read from the disk controller. The important
+** characteristic is that it is the same size as a disk sector.
+*/
+#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
+
+/*
+** The macro MEMDB is true if we are dealing with an in-memory database.
+** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
+** the value of MEMDB will be a constant and the compiler will optimize
+** out code that would never execute.
+*/
+#ifdef SQLITE_OMIT_MEMORYDB
+# define MEMDB 0
+#else
+# define MEMDB pPager->memDb
+#endif
+
+/*
+** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
+** reserved for working around a windows/posix incompatibility). It is
+** used in the journal to signify that the remainder of the journal file 
+** is devoted to storing a master journal name - there are no more pages to
+** roll back. See comments for function writeMasterJournal() for details.
+*/
+/* #define PAGER_MJ_PGNO(x) (PENDING_BYTE/((x)->pageSize)) */
+#define PAGER_MJ_PGNO(x) ((PENDING_BYTE/((x)->pageSize))+1)
+
+/*
+** The maximum legal page number is (2^31 - 1).
+*/
+#define PAGER_MAX_PGNO 2147483647
+
+/*
+** The pagerEnter() and pagerLeave() routines acquire and release
+** a mutex on each pager.  The mutex is recursive.
+**
+** This is a special-purpose mutex.  It only provides mutual exclusion
+** between the Btree and the Memory Management sqlite3_release_memory()
+** function.  It does not prevent, for example, two Btrees from accessing
+** the same pager at the same time.  Other general-purpose mutexes in
+** the btree layer handle that chore.
+*/
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  static void pagerEnter(Pager *p){
+    p->iInUseDB++;
+    if( p->iInUseMM && p->iInUseDB==1 ){
+#ifndef SQLITE_MUTEX_NOOP
+      sqlite3_mutex *mutex;
+      mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
+#endif
+      p->iInUseDB = 0;
+      sqlite3_mutex_enter(mutex);
+      p->iInUseDB = 1;
+      sqlite3_mutex_leave(mutex);
+    }
+    assert( p->iInUseMM==0 );
+  }
+  static void pagerLeave(Pager *p){
+    p->iInUseDB--;
+    assert( p->iInUseDB>=0 );
+  }
+#else
+# define pagerEnter(X)
+# define pagerLeave(X)
+#endif
+
+/*
+** Add page pPg to the end of the linked list managed by structure
+** pList (pPg becomes the last entry in the list - the most recently 
+** used). Argument pLink should point to either pPg->free or pPg->gfree,
+** depending on whether pPg is being added to the pager-specific or
+** global LRU list.
+*/
+static void listAdd(PagerLruList *pList, PagerLruLink *pLink, PgHdr *pPg){
+  pLink->pNext = 0;
+  pLink->pPrev = pList->pLast;
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  assert(pLink==&pPg->free || pLink==&pPg->gfree);
+  assert(pLink==&pPg->gfree || pList!=&sqlite3LruPageList);
+#endif
+
+  if( pList->pLast ){
+    int iOff = (char *)pLink - (char *)pPg;
+    PagerLruLink *pLastLink = (PagerLruLink *)(&((u8 *)pList->pLast)[iOff]);
+    pLastLink->pNext = pPg;
+  }else{
+    assert(!pList->pFirst);
+    pList->pFirst = pPg;
+  }
+
+  pList->pLast = pPg;
+  if( !pList->pFirstSynced && pPg->needSync==0 ){
+    pList->pFirstSynced = pPg;
+  }
+}
+
+/*
+** Remove pPg from the list managed by the structure pointed to by pList.
+**
+** Argument pLink should point to either pPg->free or pPg->gfree, depending 
+** on whether pPg is being added to the pager-specific or global LRU list.
+*/
+static void listRemove(PagerLruList *pList, PagerLruLink *pLink, PgHdr *pPg){
+  int iOff = (char *)pLink - (char *)pPg;
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  assert(pLink==&pPg->free || pLink==&pPg->gfree);
+  assert(pLink==&pPg->gfree || pList!=&sqlite3LruPageList);
+#endif
+
+  if( pPg==pList->pFirst ){
+    pList->pFirst = pLink->pNext;
+  }
+  if( pPg==pList->pLast ){
+    pList->pLast = pLink->pPrev;
+  }
+  if( pLink->pPrev ){
+    PagerLruLink *pPrevLink = (PagerLruLink *)(&((u8 *)pLink->pPrev)[iOff]);
+    pPrevLink->pNext = pLink->pNext;
+  }
+  if( pLink->pNext ){
+    PagerLruLink *pNextLink = (PagerLruLink *)(&((u8 *)pLink->pNext)[iOff]);
+    pNextLink->pPrev = pLink->pPrev;
+  }
+  if( pPg==pList->pFirstSynced ){
+    PgHdr *p = pLink->pNext;
+    while( p && p->needSync ){
+      PagerLruLink *pL = (PagerLruLink *)(&((u8 *)p)[iOff]);
+      p = pL->pNext;
+    }
+    pList->pFirstSynced = p;
+  }
+
+  pLink->pNext = pLink->pPrev = 0;
+}
+
+/* 
+** Add page pPg to the list of free pages for the pager. If 
+** memory-management is enabled, also add the page to the global 
+** list of free pages.
+*/
+static void lruListAdd(PgHdr *pPg){
+  listAdd(&pPg->pPager->lru, &pPg->free, pPg);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( !pPg->pPager->memDb ){
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+    listAdd(&sqlite3LruPageList, &pPg->gfree, pPg);
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+  }
+#endif
+}
+
+/* 
+** Remove page pPg from the list of free pages for the associated pager.
+** If memory-management is enabled, also remove pPg from the global list
+** of free pages.
+*/
+static void lruListRemove(PgHdr *pPg){
+  listRemove(&pPg->pPager->lru, &pPg->free, pPg);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( !pPg->pPager->memDb ){
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+    listRemove(&sqlite3LruPageList, &pPg->gfree, pPg);
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+  }
+#endif
+}
+
+/* 
+** This function is called just after the needSync flag has been cleared
+** from all pages managed by pPager (usually because the journal file
+** has just been synced). It updates the pPager->lru.pFirstSynced variable
+** and, if memory-management is enabled, the sqlite3LruPageList.pFirstSynced
+** variable also.
+*/
+static void lruListSetFirstSynced(Pager *pPager){
+  pPager->lru.pFirstSynced = pPager->lru.pFirst;
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( !pPager->memDb ){
+    PgHdr *p;
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+    for(p=sqlite3LruPageList.pFirst; p && p->needSync; p=p->gfree.pNext);
+    assert(p==pPager->lru.pFirstSynced || p==sqlite3LruPageList.pFirstSynced);
+    sqlite3LruPageList.pFirstSynced = p;
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+  }
+#endif
+}
+
+/*
+** Return true if page *pPg has already been written to the statement
+** journal (or statement snapshot has been created, if *pPg is part
+** of an in-memory database).
+*/
+static int pageInStatement(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  if( MEMDB ){
+    return PGHDR_TO_HIST(pPg, pPager)->inStmt;
+  }else{
+    return sqlite3BitvecTest(pPager->pInStmt, pPg->pgno);
+  }
+}
+
+/*
+** Change the size of the pager hash table to N.  N must be a power
+** of two.
+*/
+static void pager_resize_hash_table(Pager *pPager, int N){
+  PgHdr **aHash, *pPg;
+  assert( N>0 && (N&(N-1))==0 );
+#ifdef SQLITE_MALLOC_SOFT_LIMIT
+  if( N*sizeof(aHash[0])>SQLITE_MALLOC_SOFT_LIMIT ){
+    N = SQLITE_MALLOC_SOFT_LIMIT/sizeof(aHash[0]);
+  }
+  if( N==pPager->nHash ) return;
+#endif
+  pagerLeave(pPager);
+  if( pPager->aHash!=0 ) sqlite3FaultBeginBenign(SQLITE_FAULTINJECTOR_MALLOC);
+  aHash = sqlite3MallocZero( sizeof(aHash[0])*N );
+  if( pPager->aHash!=0 ) sqlite3FaultEndBenign(SQLITE_FAULTINJECTOR_MALLOC);
+  pagerEnter(pPager);
+  if( aHash==0 ){
+    /* Failure to rehash is not an error.  It is only a performance hit. */
+    return;
+  }
+  sqlite3_free(pPager->aHash);
+  pPager->nHash = N;
+  pPager->aHash = aHash;
+  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+    int h;
+    if( pPg->pgno==0 ){
+      assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
+      continue;
+    }
+    h = pPg->pgno & (N-1);
+    pPg->pNextHash = aHash[h];
+    if( aHash[h] ){
+      aHash[h]->pPrevHash = pPg;
+    }
+    aHash[h] = pPg;
+    pPg->pPrevHash = 0;
+  }
+}
+
+/*
+** Read a 32-bit integer from the given file descriptor.  Store the integer
+** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
+** error code is something goes wrong.
+**
+** All values are stored on disk as big-endian.
+*/
+static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
+  unsigned char ac[4];
+  int rc = sqlite3OsRead(fd, ac, sizeof(ac), offset);
+  if( rc==SQLITE_OK ){
+    *pRes = sqlite3Get4byte(ac);
+  }
+  return rc;
+}
+
+/*
+** Write a 32-bit integer into a string buffer in big-endian byte order.
+*/
+#define put32bits(A,B)  sqlite3Put4byte((u8*)A,B)
+
+/*
+** Write a 32-bit integer into the given file descriptor.  Return SQLITE_OK
+** on success or an error code is something goes wrong.
+*/
+static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
+  char ac[4];
+  put32bits(ac, val);
+  return sqlite3OsWrite(fd, ac, 4, offset);
+}
+
+/*
+** If file pFd is open, call sqlite3OsUnlock() on it.
+*/
+static int osUnlock(sqlite3_file *pFd, int eLock){
+  if( !pFd->pMethods ){
+    return SQLITE_OK;
+  }
+  return sqlite3OsUnlock(pFd, eLock);
+}
+
+/*
+** This function determines whether or not the atomic-write optimization
+** can be used with this pager. The optimization can be used if:
+**
+**  (a) the value returned by OsDeviceCharacteristics() indicates that
+**      a database page may be written atomically, and
+**  (b) the value returned by OsSectorSize() is less than or equal
+**      to the page size.
+**
+** If the optimization cannot be used, 0 is returned. If it can be used,
+** then the value returned is the size of the journal file when it
+** contains rollback data for exactly one page.
+*/
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+static int jrnlBufferSize(Pager *pPager){
+  int dc;           /* Device characteristics */
+  int nSector;      /* Sector size */
+  int nPage;        /* Page size */
+  sqlite3_file *fd = pPager->fd;
+
+  if( fd->pMethods ){
+    dc = sqlite3OsDeviceCharacteristics(fd);
+    nSector = sqlite3OsSectorSize(fd);
+    nPage = pPager->pageSize;
+  }
+
+  assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+  assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+
+  if( !fd->pMethods || (dc&(SQLITE_IOCAP_ATOMIC|(nPage>>8))&&nSector<=nPage) ){
+    return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
+  }
+  return 0;
+}
+#endif
+
+/*
+** This function should be called when an error occurs within the pager
+** code. The first argument is a pointer to the pager structure, the
+** second the error-code about to be returned by a pager API function. 
+** The value returned is a copy of the second argument to this function. 
+**
+** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
+** the error becomes persistent. Until the persisten error is cleared,
+** subsequent API calls on this Pager will immediately return the same 
+** error code.
+**
+** A persistent error indicates that the contents of the pager-cache 
+** cannot be trusted. This state can be cleared by completely discarding 
+** the contents of the pager-cache. If a transaction was active when
+** the persistent error occured, then the rollback journal may need
+** to be replayed.
+*/
+static void pager_unlock(Pager *pPager);
+static int pager_error(Pager *pPager, int rc){
+  int rc2 = rc & 0xff;
+  assert(
+       pPager->errCode==SQLITE_FULL ||
+       pPager->errCode==SQLITE_OK ||
+       (pPager->errCode & 0xff)==SQLITE_IOERR
+  );
+  if(
+    rc2==SQLITE_FULL ||
+    rc2==SQLITE_IOERR ||
+    rc2==SQLITE_CORRUPT
+  ){
+    pPager->errCode = rc;
+    if( pPager->state==PAGER_UNLOCK && pPager->nRef==0 ){
+      /* If the pager is already unlocked, call pager_unlock() now to
+      ** clear the error state and ensure that the pager-cache is 
+      ** completely empty.
+      */
+      pager_unlock(pPager);
+    }
+  }
+  return rc;
+}
+
+/*
+** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
+** on the cache using a hash function.  This is used for testing
+** and debugging only.
+*/
+#ifdef SQLITE_CHECK_PAGES
+/*
+** Return a 32-bit hash of the page data for pPage.
+*/
+static u32 pager_datahash(int nByte, unsigned char *pData){
+  u32 hash = 0;
+  int i;
+  for(i=0; i<nByte; i++){
+    hash = (hash*1039) + pData[i];
+  }
+  return hash;
+}
+static u32 pager_pagehash(PgHdr *pPage){
+  return pager_datahash(pPage->pPager->pageSize, 
+                        (unsigned char *)PGHDR_TO_DATA(pPage));
+}
+
+/*
+** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
+** is defined, and NDEBUG is not defined, an assert() statement checks
+** that the page is either dirty or still matches the calculated page-hash.
+*/
+#define CHECK_PAGE(x) checkPage(x)
+static void checkPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( !pPg->pageHash || pPager->errCode || MEMDB || pPg->dirty || 
+      pPg->pageHash==pager_pagehash(pPg) );
+}
+
+#else
+#define pager_datahash(X,Y)  0
+#define pager_pagehash(X)  0
+#define CHECK_PAGE(x)
+#endif
+
+/*
+** When this is called the journal file for pager pPager must be open.
+** The master journal file name is read from the end of the file and 
+** written into memory supplied by the caller. 
+**
+** zMaster must point to a buffer of at least nMaster bytes allocated by
+** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
+** enough space to write the master journal name). If the master journal
+** name in the journal is longer than nMaster bytes (including a
+** nul-terminator), then this is handled as if no master journal name
+** were present in the journal.
+**
+** If no master journal file name is present zMaster[0] is set to 0 and
+** SQLITE_OK returned.
+*/
+static int readMasterJournal(sqlite3_file *pJrnl, char *zMaster, int nMaster){
+  int rc;
+  u32 len;
+  i64 szJ;
+  u32 cksum;
+  int i;
+  unsigned char aMagic[8]; /* A buffer to hold the magic header */
+
+  zMaster[0] = '\0';
+
+  rc = sqlite3OsFileSize(pJrnl, &szJ);
+  if( rc!=SQLITE_OK || szJ<16 ) return rc;
+
+  rc = read32bits(pJrnl, szJ-16, &len);
+  if( rc!=SQLITE_OK ) return rc;
+
+  if( len>=nMaster ){
+    return SQLITE_OK;
+  }
+
+  rc = read32bits(pJrnl, szJ-12, &cksum);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8);
+  if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;
+
+  rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  zMaster[len] = '\0';
+
+  /* See if the checksum matches the master journal name */
+  for(i=0; i<len; i++){
+    cksum -= zMaster[i];
+   }
+  if( cksum ){
+    /* If the checksum doesn't add up, then one or more of the disk sectors
+    ** containing the master journal filename is corrupted. This means
+    ** definitely roll back, so just return SQLITE_OK and report a (nul)
+    ** master-journal filename.
+    */
+    zMaster[0] = '\0';
+  }
+   
+  return SQLITE_OK;
+}
+
+/*
+** Seek the journal file descriptor to the next sector boundary where a
+** journal header may be read or written. Pager.journalOff is updated with
+** the new seek offset.
+**
+** i.e for a sector size of 512:
+**
+** Input Offset              Output Offset
+** ---------------------------------------
+** 0                         0
+** 512                       512
+** 100                       512
+** 2000                      2048
+** 
+*/
+static void seekJournalHdr(Pager *pPager){
+  i64 offset = 0;
+  i64 c = pPager->journalOff;
+  if( c ){
+    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
+  }
+  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
+  assert( offset>=c );
+  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
+  pPager->journalOff = offset;
+}
+
+/*
+** Write zeros over the header of the journal file.  This has the
+** effect of invalidating the journal file and committing the
+** transaction.
+*/
+static int zeroJournalHdr(Pager *pPager, int doTruncate){
+  int rc = SQLITE_OK;
+  static const char zeroHdr[28];
+
+  if( pPager->journalOff ){
+    IOTRACE(("JZEROHDR %p\n", pPager))
+    if( doTruncate ){
+      rc = sqlite3OsTruncate(pPager->jfd, 0);
+    }else{
+      rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->sync_flags);
+    }
+  }
+  return rc;
+}
+
+/*
+** The journal file must be open when this routine is called. A journal
+** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
+** current location.
+**
+** The format for the journal header is as follows:
+** - 8 bytes: Magic identifying journal format.
+** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
+** - 4 bytes: Random number used for page hash.
+** - 4 bytes: Initial database page count.
+** - 4 bytes: Sector size used by the process that wrote this journal.
+** - 4 bytes: Database page size.
+** 
+** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
+*/
+static int writeJournalHdr(Pager *pPager){
+  int rc = SQLITE_OK;
+  char *zHeader = pPager->pTmpSpace;
+  int nHeader = pPager->pageSize;
+  int nWrite;
+
+  if( nHeader>JOURNAL_HDR_SZ(pPager) ){
+    nHeader = JOURNAL_HDR_SZ(pPager);
+  }
+
+  if( pPager->stmtHdrOff==0 ){
+    pPager->stmtHdrOff = pPager->journalOff;
+  }
+
+  seekJournalHdr(pPager);
+  pPager->journalHdr = pPager->journalOff;
+
+  memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+
+  /* 
+  ** Write the nRec Field - the number of page records that follow this
+  ** journal header. Normally, zero is written to this value at this time.
+  ** After the records are added to the journal (and the journal synced, 
+  ** if in full-sync mode), the zero is overwritten with the true number
+  ** of records (see syncJournal()).
+  **
+  ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
+  ** reading the journal this value tells SQLite to assume that the
+  ** rest of the journal file contains valid page records. This assumption
+  ** is dangerous, as if a failure occured whilst writing to the journal
+  ** file it may contain some garbage data. There are two scenarios
+  ** where this risk can be ignored:
+  **
+  **   * When the pager is in no-sync mode. Corruption can follow a
+  **     power failure in this case anyway.
+  **
+  **   * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
+  **     that garbage data is never appended to the journal file.
+  */
+  assert(pPager->fd->pMethods||pPager->noSync);
+  if( (pPager->noSync) 
+   || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND) 
+  ){
+    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
+  }else{
+    put32bits(&zHeader[sizeof(aJournalMagic)], 0);
+  }
+
+  /* The random check-hash initialiser */ 
+  sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
+  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
+  /* The initial database size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbSize);
+  /* The assumed sector size for this process */
+  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
+  if( pPager->journalHdr==0 ){
+    /* The page size */
+    put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
+  }
+
+  for(nWrite=0; rc==SQLITE_OK&&nWrite<JOURNAL_HDR_SZ(pPager); nWrite+=nHeader){
+    IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, nHeader))
+    rc = sqlite3OsWrite(pPager->jfd, zHeader, nHeader, pPager->journalOff);
+    pPager->journalOff += nHeader;
+  }
+
+  return rc;
+}
+
+/*
+** The journal file must be open when this is called. A journal header file
+** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
+** file. See comments above function writeJournalHdr() for a description of
+** the journal header format.
+**
+** If the header is read successfully, *nRec is set to the number of
+** page records following this header and *dbSize is set to the size of the
+** database before the transaction began, in pages. Also, pPager->cksumInit
+** is set to the value read from the journal header. SQLITE_OK is returned
+** in this case.
+**
+** If the journal header file appears to be corrupted, SQLITE_DONE is
+** returned and *nRec and *dbSize are not set.  If JOURNAL_HDR_SZ bytes
+** cannot be read from the journal file an error code is returned.
+*/
+static int readJournalHdr(
+  Pager *pPager, 
+  i64 journalSize,
+  u32 *pNRec, 
+  u32 *pDbSize
+){
+  int rc;
+  unsigned char aMagic[8]; /* A buffer to hold the magic header */
+  i64 jrnlOff;
+  int iPageSize;
+
+  seekJournalHdr(pPager);
+  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
+    return SQLITE_DONE;
+  }
+  jrnlOff = pPager->journalOff;
+
+  rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), jrnlOff);
+  if( rc ) return rc;
+  jrnlOff += sizeof(aMagic);
+
+  if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
+    return SQLITE_DONE;
+  }
+
+  rc = read32bits(pPager->jfd, jrnlOff, pNRec);
+  if( rc ) return rc;
+
+  rc = read32bits(pPager->jfd, jrnlOff+4, &pPager->cksumInit);
+  if( rc ) return rc;
+
+  rc = read32bits(pPager->jfd, jrnlOff+8, pDbSize);
+  if( rc ) return rc;
+
+  rc = read32bits(pPager->jfd, jrnlOff+16, (u32 *)&iPageSize);
+  if( rc==SQLITE_OK 
+   && iPageSize>=512 
+   && iPageSize<=SQLITE_MAX_PAGE_SIZE 
+   && ((iPageSize-1)&iPageSize)==0 
+  ){
+    u16 pagesize = iPageSize;
+    rc = sqlite3PagerSetPagesize(pPager, &pagesize);
+  }
+  if( rc ) return rc;
+
+  /* Update the assumed sector-size to match the value used by 
+  ** the process that created this journal. If this journal was
+  ** created by a process other than this one, then this routine
+  ** is being called from within pager_playback(). The local value
+  ** of Pager.sectorSize is restored at the end of that routine.
+  */
+  rc = read32bits(pPager->jfd, jrnlOff+12, (u32 *)&pPager->sectorSize);
+  if( rc ) return rc;
+
+  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
+  return SQLITE_OK;
+}
+
+
+/*
+** Write the supplied master journal name into the journal file for pager
+** pPager at the current location. The master journal name must be the last
+** thing written to a journal file. If the pager is in full-sync mode, the
+** journal file descriptor is advanced to the next sector boundary before
+** anything is written. The format is:
+**
+** + 4 bytes: PAGER_MJ_PGNO.
+** + N bytes: length of master journal name.
+** + 4 bytes: N
+** + 4 bytes: Master journal name checksum.
+** + 8 bytes: aJournalMagic[].
+**
+** The master journal page checksum is the sum of the bytes in the master
+** journal name.
+**
+** If zMaster is a NULL pointer (occurs for a single database transaction), 
+** this call is a no-op.
+*/
+static int writeMasterJournal(Pager *pPager, const char *zMaster){
+  int rc;
+  int len; 
+  int i; 
+  i64 jrnlOff;
+  i64 jrnlSize;
+  u32 cksum = 0;
+  char zBuf[sizeof(aJournalMagic)+2*4];
+
+  if( !zMaster || pPager->setMaster) return SQLITE_OK;
+  pPager->setMaster = 1;
+
+  len = strlen(zMaster);
+  for(i=0; i<len; i++){
+    cksum += zMaster[i];
+  }
+
+  /* If in full-sync mode, advance to the next disk sector before writing
+  ** the master journal name. This is in case the previous page written to
+  ** the journal has already been synced.
+  */
+  if( pPager->fullSync ){
+    seekJournalHdr(pPager);
+  }
+  jrnlOff = pPager->journalOff;
+  pPager->journalOff += (len+20);
+
+  rc = write32bits(pPager->jfd, jrnlOff, PAGER_MJ_PGNO(pPager));
+  if( rc!=SQLITE_OK ) return rc;
+  jrnlOff += 4;
+
+  rc = sqlite3OsWrite(pPager->jfd, zMaster, len, jrnlOff);
+  if( rc!=SQLITE_OK ) return rc;
+  jrnlOff += len;
+
+  put32bits(zBuf, len);
+  put32bits(&zBuf[4], cksum);
+  memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
+  rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic), jrnlOff);
+  jrnlOff += 8+sizeof(aJournalMagic);
+  pPager->needSync = !pPager->noSync;
+
+  /* If the pager is in peristent-journal mode, then the physical 
+  ** journal-file may extend past the end of the master-journal name
+  ** and 8 bytes of magic data just written to the file. This is 
+  ** dangerous because the code to rollback a hot-journal file
+  ** will not be able to find the master-journal name to determine 
+  ** whether or not the journal is hot. 
+  **
+  ** Easiest thing to do in this scenario is to truncate the journal 
+  ** file to the required size.
+  */ 
+  if( (rc==SQLITE_OK)
+   && (rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))==SQLITE_OK
+   && jrnlSize>jrnlOff
+  ){
+    rc = sqlite3OsTruncate(pPager->jfd, jrnlOff);
+  }
+  return rc;
+}
+
+/*
+** Add or remove a page from the list of all pages that are in the
+** statement journal.
+**
+** The Pager keeps a separate list of pages that are currently in
+** the statement journal.  This helps the sqlite3PagerStmtCommit()
+** routine run MUCH faster for the common case where there are many
+** pages in memory but only a few are in the statement journal.
+*/
+static void page_add_to_stmt_list(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+  assert( MEMDB );
+  if( !pHist->inStmt ){
+    assert( pHist->pPrevStmt==0 && pHist->pNextStmt==0 );
+    if( pPager->pStmt ){
+      PGHDR_TO_HIST(pPager->pStmt, pPager)->pPrevStmt = pPg;
+    }
+    pHist->pNextStmt = pPager->pStmt;
+    pPager->pStmt = pPg;
+    pHist->inStmt = 1;
+  }
+}
+
+/*
+** Find a page in the hash table given its page number.  Return
+** a pointer to the page or NULL if not found.
+*/
+static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
+  PgHdr *p;
+  if( pPager->aHash==0 ) return 0;
+  p = pPager->aHash[pgno & (pPager->nHash-1)];
+  while( p && p->pgno!=pgno ){
+    p = p->pNextHash;
+  }
+  return p;
+}
+
+/*
+** Clear the in-memory cache.  This routine
+** sets the state of the pager back to what it was when it was first
+** opened.  Any outstanding pages are invalidated and subsequent attempts
+** to access those pages will likely result in a coredump.
+*/
+static void pager_reset(Pager *pPager){
+  PgHdr *pPg, *pNext;
+  if( pPager->errCode ) return;
+  for(pPg=pPager->pAll; pPg; pPg=pNext){
+    IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
+    PAGER_INCR(sqlite3_pager_pgfree_count);
+    pNext = pPg->pNextAll;
+    lruListRemove(pPg);
+    sqlite3_free(pPg->pData);
+    sqlite3_free(pPg);
+  }
+  assert(pPager->lru.pFirst==0);
+  assert(pPager->lru.pFirstSynced==0);
+  assert(pPager->lru.pLast==0);
+  pPager->pStmt = 0;
+  pPager->pAll = 0;
+  pPager->pDirty = 0;
+  pPager->nHash = 0;
+  sqlite3_free(pPager->aHash);
+  pPager->nPage = 0;
+  pPager->aHash = 0;
+  pPager->nRef = 0;
+}
+
+/*
+** Unlock the database file. 
+**
+** If the pager is currently in error state, discard the contents of 
+** the cache and reset the Pager structure internal state. If there is
+** an open journal-file, then the next time a shared-lock is obtained
+** on the pager file (by this or any other process), it will be
+** treated as a hot-journal and rolled back.
+*/
+static void pager_unlock(Pager *pPager){
+  if( !pPager->exclusiveMode ){
+    if( !MEMDB ){
+      int rc = osUnlock(pPager->fd, NO_LOCK);
+      if( rc ) pPager->errCode = rc;
+      pPager->dbSize = -1;
+      IOTRACE(("UNLOCK %p\n", pPager))
+
+      /* Always close the journal file when dropping the database lock.
+      ** Otherwise, another connection with journal_mode=delete might
+      ** delete the file out from under us.
+      */
+      if( pPager->journalOpen ){
+        sqlite3OsClose(pPager->jfd);
+        pPager->journalOpen = 0;
+        sqlite3BitvecDestroy(pPager->pInJournal);
+        pPager->pInJournal = 0;
+      }
+
+      /* If Pager.errCode is set, the contents of the pager cache cannot be
+      ** trusted. Now that the pager file is unlocked, the contents of the
+      ** cache can be discarded and the error code safely cleared.
+      */
+      if( pPager->errCode ){
+        if( rc==SQLITE_OK ) pPager->errCode = SQLITE_OK;
+        pager_reset(pPager);
+        if( pPager->stmtOpen ){
+          sqlite3OsClose(pPager->stfd);
+          sqlite3BitvecDestroy(pPager->pInStmt);
+          pPager->pInStmt = 0;
+        }
+        pPager->stmtOpen = 0;
+        pPager->stmtInUse = 0;
+        pPager->journalOff = 0;
+        pPager->journalStarted = 0;
+        pPager->stmtAutoopen = 0;
+        pPager->origDbSize = 0;
+      }
+    }
+
+    if( !MEMDB || pPager->errCode==SQLITE_OK ){
+      pPager->state = PAGER_UNLOCK;
+      pPager->changeCountDone = 0;
+    }
+  }
+}
+
+/*
+** Execute a rollback if a transaction is active and unlock the 
+** database file. If the pager has already entered the error state, 
+** do not attempt the rollback.
+*/
+static void pagerUnlockAndRollback(Pager *p){
+  /* assert( p->state>=PAGER_RESERVED || p->journalOpen==0 ); */
+  if( p->errCode==SQLITE_OK && p->state>=PAGER_RESERVED ){
+    sqlite3FaultBeginBenign(-1);
+    sqlite3PagerRollback(p);
+    sqlite3FaultEndBenign(-1);
+  }
+  pager_unlock(p);
+#if 0
+  assert( p->errCode || !p->journalOpen || (p->exclusiveMode&&!p->journalOff) );
+  assert( p->errCode || !p->stmtOpen || p->exclusiveMode );
+#endif
+}
+
+/*
+** This routine ends a transaction.  A transaction is ended by either
+** a COMMIT or a ROLLBACK.
+**
+** When this routine is called, the pager has the journal file open and
+** a RESERVED or EXCLUSIVE lock on the database.  This routine will release
+** the database lock and acquires a SHARED lock in its place if that is
+** the appropriate thing to do.  Release locks usually is appropriate,
+** unless we are in exclusive access mode or unless this is a 
+** COMMIT AND BEGIN or ROLLBACK AND BEGIN operation.
+**
+** The journal file is either deleted or truncated.
+**
+** TODO: Consider keeping the journal file open for temporary databases.
+** This might give a performance improvement on windows where opening
+** a file is an expensive operation.
+*/
+static int pager_end_transaction(Pager *pPager, int hasMaster){
+  PgHdr *pPg;
+  int rc = SQLITE_OK;
+  int rc2 = SQLITE_OK;
+  assert( !MEMDB );
+  if( pPager->state<PAGER_RESERVED ){
+    return SQLITE_OK;
+  }
+  sqlite3PagerStmtCommit(pPager);
+  if( pPager->stmtOpen && !pPager->exclusiveMode ){
+    sqlite3OsClose(pPager->stfd);
+    pPager->stmtOpen = 0;
+  }
+  if( pPager->journalOpen ){
+    if( pPager->exclusiveMode 
+     || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+    ){
+      rc = zeroJournalHdr(pPager, hasMaster);
+      pager_error(pPager, rc);
+      pPager->journalOff = 0;
+      pPager->journalStarted = 0;
+    }else{
+      sqlite3OsClose(pPager->jfd);
+      pPager->journalOpen = 0;
+      if( rc==SQLITE_OK ){
+        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+      }
+    }
+    sqlite3BitvecDestroy(pPager->pInJournal);
+    pPager->pInJournal = 0;
+    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+      pPg->inJournal = 0;
+      pPg->dirty = 0;
+      pPg->needSync = 0;
+      pPg->alwaysRollback = 0;
+#ifdef SQLITE_CHECK_PAGES
+      pPg->pageHash = pager_pagehash(pPg);
+#endif
+    }
+    pPager->pDirty = 0;
+    pPager->dirtyCache = 0;
+    pPager->nRec = 0;
+  }else{
+    assert( pPager->pInJournal==0 );
+  }
+
+  if( !pPager->exclusiveMode ){
+    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
+    pPager->state = PAGER_SHARED;
+  }else if( pPager->state==PAGER_SYNCED ){
+    pPager->state = PAGER_EXCLUSIVE;
+  }
+  pPager->origDbSize = 0;
+  pPager->setMaster = 0;
+  pPager->needSync = 0;
+  lruListSetFirstSynced(pPager);
+  pPager->dbSize = -1;
+  pPager->dbModified = 0;
+
+  return (rc==SQLITE_OK?rc2:rc);
+}
+
+/*
+** Compute and return a checksum for the page of data.
+**
+** This is not a real checksum.  It is really just the sum of the 
+** random initial value and the page number.  We experimented with
+** a checksum of the entire data, but that was found to be too slow.
+**
+** Note that the page number is stored at the beginning of data and
+** the checksum is stored at the end.  This is important.  If journal
+** corruption occurs due to a power failure, the most likely scenario
+** is that one end or the other of the record will be changed.  It is
+** much less likely that the two ends of the journal record will be
+** correct and the middle be corrupt.  Thus, this "checksum" scheme,
+** though fast and simple, catches the mostly likely kind of corruption.
+**
+** FIX ME:  Consider adding every 200th (or so) byte of the data to the
+** checksum.  That way if a single page spans 3 or more disk sectors and
+** only the middle sector is corrupt, we will still have a reasonable
+** chance of failing the checksum and thus detecting the problem.
+*/
+static u32 pager_cksum(Pager *pPager, const u8 *aData){
+  u32 cksum = pPager->cksumInit;
+  int i = pPager->pageSize-200;
+  while( i>0 ){
+    cksum += aData[i];
+    i -= 200;
+  }
+  return cksum;
+}
+
+/* Forward declaration */
+static void makeClean(PgHdr*);
+
+/*
+** Read a single page from the journal file opened on file descriptor
+** jfd.  Playback this one page.
+**
+** If useCksum==0 it means this journal does not use checksums.  Checksums
+** are not used in statement journals because statement journals do not
+** need to survive power failures.
+*/
+static int pager_playback_one_page(
+  Pager *pPager, 
+  sqlite3_file *jfd,
+  i64 offset,
+  int useCksum
+){
+  int rc;
+  PgHdr *pPg;                   /* An existing page in the cache */
+  Pgno pgno;                    /* The page number of a page in journal */
+  u32 cksum;                    /* Checksum used for sanity checking */
+  u8 *aData = (u8 *)pPager->pTmpSpace;   /* Temp storage for a page */
+
+  /* useCksum should be true for the main journal and false for
+  ** statement journals.  Verify that this is always the case
+  */
+  assert( jfd == (useCksum ? pPager->jfd : pPager->stfd) );
+  assert( aData );
+
+  rc = read32bits(jfd, offset, &pgno);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = sqlite3OsRead(jfd, aData, pPager->pageSize, offset+4);
+  if( rc!=SQLITE_OK ) return rc;
+  pPager->journalOff += pPager->pageSize + 4;
+
+  /* Sanity checking on the page.  This is more important that I originally
+  ** thought.  If a power failure occurs while the journal is being written,
+  ** it could cause invalid data to be written into the journal.  We need to
+  ** detect this invalid data (with high probability) and ignore it.
+  */
+  if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
+    return SQLITE_DONE;
+  }
+  if( pgno>(unsigned)pPager->dbSize ){
+    return SQLITE_OK;
+  }
+  if( useCksum ){
+    rc = read32bits(jfd, offset+pPager->pageSize+4, &cksum);
+    if( rc ) return rc;
+    pPager->journalOff += 4;
+    if( pager_cksum(pPager, aData)!=cksum ){
+      return SQLITE_DONE;
+    }
+  }
+
+  assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
+
+  /* If the pager is in RESERVED state, then there must be a copy of this
+  ** page in the pager cache. In this case just update the pager cache,
+  ** not the database file. The page is left marked dirty in this case.
+  **
+  ** An exception to the above rule: If the database is in no-sync mode
+  ** and a page is moved during an incremental vacuum then the page may
+  ** not be in the pager cache. Later: if a malloc() or IO error occurs
+  ** during a Movepage() call, then the page may not be in the cache
+  ** either. So the condition described in the above paragraph is not
+  ** assert()able.
+  **
+  ** If in EXCLUSIVE state, then we update the pager cache if it exists
+  ** and the main file. The page is then marked not dirty.
+  **
+  ** Ticket #1171:  The statement journal might contain page content that is
+  ** different from the page content at the start of the transaction.
+  ** This occurs when a page is changed prior to the start of a statement
+  ** then changed again within the statement.  When rolling back such a
+  ** statement we must not write to the original database unless we know
+  ** for certain that original page contents are synced into the main rollback
+  ** journal.  Otherwise, a power loss might leave modified data in the
+  ** database file without an entry in the rollback journal that can
+  ** restore the database to its original form.  Two conditions must be
+  ** met before writing to the database files. (1) the database must be
+  ** locked.  (2) we know that the original page content is fully synced
+  ** in the main journal either because the page is not in cache or else
+  ** the page is marked as needSync==0.
+  **
+  ** 2008-04-14:  When attempting to vacuum a corrupt database file, it
+  ** is possible to fail a statement on a database that does not yet exist.
+  ** Do not attempt to write if database file has never been opened.
+  */
+  pPg = pager_lookup(pPager, pgno);
+  PAGERTRACE4("PLAYBACK %d page %d hash(%08x)\n",
+               PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData));
+  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0)
+        && pPager->fd->pMethods ){
+    i64 offset = (pgno-1)*(i64)pPager->pageSize;
+    rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize, offset);
+    if( pPg ){
+      makeClean(pPg);
+    }
+  }
+  if( pPg ){
+    /* No page should ever be explicitly rolled back that is in use, except
+    ** for page 1 which is held in use in order to keep the lock on the
+    ** database active. However such a page may be rolled back as a result
+    ** of an internal error resulting in an automatic call to
+    ** sqlite3PagerRollback().
+    */
+    void *pData;
+    /* assert( pPg->nRef==0 || pPg->pgno==1 ); */
+    pData = PGHDR_TO_DATA(pPg);
+    memcpy(pData, aData, pPager->pageSize);
+    if( pPager->xReiniter ){
+      pPager->xReiniter(pPg, pPager->pageSize);
+    }
+#ifdef SQLITE_CHECK_PAGES
+    pPg->pageHash = pager_pagehash(pPg);
+#endif
+    /* If this was page 1, then restore the value of Pager.dbFileVers.
+    ** Do this before any decoding. */
+    if( pgno==1 ){
+      memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
+    }
+
+    /* Decode the page just read from disk */
+    CODEC1(pPager, pData, pPg->pgno, 3);
+  }
+  return rc;
+}
+
+/*
+** Parameter zMaster is the name of a master journal file. A single journal
+** file that referred to the master journal file has just been rolled back.
+** This routine checks if it is possible to delete the master journal file,
+** and does so if it is.
+**
+** Argument zMaster may point to Pager.pTmpSpace. So that buffer is not 
+** available for use within this function.
+**
+**
+** The master journal file contains the names of all child journals.
+** To tell if a master journal can be deleted, check to each of the
+** children.  If all children are either missing or do not refer to
+** a different master journal, then this master journal can be deleted.
+*/
+static int pager_delmaster(Pager *pPager, const char *zMaster){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  int rc;
+  int master_open = 0;
+  sqlite3_file *pMaster;
+  sqlite3_file *pJournal;
+  char *zMasterJournal = 0; /* Contents of master journal file */
+  i64 nMasterJournal;       /* Size of master journal file */
+
+  /* Open the master journal file exclusively in case some other process
+  ** is running this routine also. Not that it makes too much difference.
+  */
+  pMaster = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile * 2);
+  pJournal = (sqlite3_file *)(((u8 *)pMaster) + pVfs->szOsFile);
+  if( !pMaster ){
+    rc = SQLITE_NOMEM;
+  }else{
+    int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MASTER_JOURNAL);
+    rc = sqlite3OsOpen(pVfs, zMaster, pMaster, flags, 0);
+  }
+  if( rc!=SQLITE_OK ) goto delmaster_out;
+  master_open = 1;
+
+  rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
+  if( rc!=SQLITE_OK ) goto delmaster_out;
+
+  if( nMasterJournal>0 ){
+    char *zJournal;
+    char *zMasterPtr = 0;
+    int nMasterPtr = pPager->pVfs->mxPathname+1;
+
+    /* Load the entire master journal file into space obtained from
+    ** sqlite3_malloc() and pointed to by zMasterJournal. 
+    */
+    zMasterJournal = (char *)sqlite3_malloc(nMasterJournal + nMasterPtr);
+    if( !zMasterJournal ){
+      rc = SQLITE_NOMEM;
+      goto delmaster_out;
+    }
+    zMasterPtr = &zMasterJournal[nMasterJournal];
+    rc = sqlite3OsRead(pMaster, zMasterJournal, nMasterJournal, 0);
+    if( rc!=SQLITE_OK ) goto delmaster_out;
+
+    zJournal = zMasterJournal;
+    while( (zJournal-zMasterJournal)<nMasterJournal ){
+      rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS);
+      if( rc!=0 && rc!=1 ){
+        rc = SQLITE_IOERR_NOMEM;
+        goto delmaster_out;
+      }
+      if( rc==1 ){
+        /* One of the journals pointed to by the master journal exists.
+        ** Open it and check if it points at the master journal. If
+        ** so, return without deleting the master journal file.
+        */
+        int c;
+        int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL);
+        rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
+        if( rc!=SQLITE_OK ){
+          goto delmaster_out;
+        }
+
+        rc = readMasterJournal(pJournal, zMasterPtr, nMasterPtr);
+        sqlite3OsClose(pJournal);
+        if( rc!=SQLITE_OK ){
+          goto delmaster_out;
+        }
+
+        c = zMasterPtr[0]!=0 && strcmp(zMasterPtr, zMaster)==0;
+        if( c ){
+          /* We have a match. Do not delete the master journal file. */
+          goto delmaster_out;
+        }
+      }
+      zJournal += (strlen(zJournal)+1);
+    }
+  }
+  
+  rc = sqlite3OsDelete(pVfs, zMaster, 0);
+
+delmaster_out:
+  if( zMasterJournal ){
+    sqlite3_free(zMasterJournal);
+  }  
+  if( master_open ){
+    sqlite3OsClose(pMaster);
+  }
+  sqlite3_free(pMaster);
+  return rc;
+}
+
+
+static void pager_truncate_cache(Pager *pPager);
+
+/*
+** Truncate the main file of the given pager to the number of pages
+** indicated. Also truncate the cached representation of the file.
+**
+** Might might be the case that the file on disk is smaller than nPage.
+** This can happen, for example, if we are in the middle of a transaction
+** which has extended the file size and the new pages are still all held
+** in cache, then an INSERT or UPDATE does a statement rollback.  Some
+** operating system implementations can get confused if you try to
+** truncate a file to some size that is larger than it currently is,
+** so detect this case and write a single zero byte to the end of the new
+** file instead.
+*/
+static int pager_truncate(Pager *pPager, int nPage){
+  int rc = SQLITE_OK;
+  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
+    i64 currentSize, newSize;
+    rc = sqlite3OsFileSize(pPager->fd, &currentSize);
+    newSize = pPager->pageSize*(i64)nPage;
+    if( rc==SQLITE_OK && currentSize!=newSize ){
+      if( currentSize>newSize ){
+        rc = sqlite3OsTruncate(pPager->fd, newSize);
+      }else{
+        rc = sqlite3OsWrite(pPager->fd, "", 1, newSize-1);
+      }
+    }
+  }
+  if( rc==SQLITE_OK ){
+    pPager->dbSize = nPage;
+    pager_truncate_cache(pPager);
+  }
+  return rc;
+}
+
+/*
+** Set the sectorSize for the given pager.
+**
+** The sector size is at least as big as the sector size reported
+** by sqlite3OsSectorSize().  The minimum sector size is 512.
+*/
+static void setSectorSize(Pager *pPager){
+  assert(pPager->fd->pMethods||pPager->tempFile);
+  if( !pPager->tempFile ){
+    /* Sector size doesn't matter for temporary files. Also, the file
+    ** may not have been opened yet, in whcih case the OsSectorSize()
+    ** call will segfault.
+    */
+    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
+  }
+  if( pPager->sectorSize<512 ){
+    pPager->sectorSize = 512;
+  }
+}
+
+/*
+** Playback the journal and thus restore the database file to
+** the state it was in before we started making changes.  
+**
+** The journal file format is as follows: 
+**
+**  (1)  8 byte prefix.  A copy of aJournalMagic[].
+**  (2)  4 byte big-endian integer which is the number of valid page records
+**       in the journal.  If this value is 0xffffffff, then compute the
+**       number of page records from the journal size.
+**  (3)  4 byte big-endian integer which is the initial value for the 
+**       sanity checksum.
+**  (4)  4 byte integer which is the number of pages to truncate the
+**       database to during a rollback.
+**  (5)  4 byte big-endian integer which is the sector size.  The header
+**       is this many bytes in size.
+**  (6)  4 byte big-endian integer which is the page case.
+**  (7)  4 byte integer which is the number of bytes in the master journal
+**       name.  The value may be zero (indicate that there is no master
+**       journal.)
+**  (8)  N bytes of the master journal name.  The name will be nul-terminated
+**       and might be shorter than the value read from (5).  If the first byte
+**       of the name is \000 then there is no master journal.  The master
+**       journal name is stored in UTF-8.
+**  (9)  Zero or more pages instances, each as follows:
+**        +  4 byte page number.
+**        +  pPager->pageSize bytes of data.
+**        +  4 byte checksum
+**
+** When we speak of the journal header, we mean the first 8 items above.
+** Each entry in the journal is an instance of the 9th item.
+**
+** Call the value from the second bullet "nRec".  nRec is the number of
+** valid page entries in the journal.  In most cases, you can compute the
+** value of nRec from the size of the journal file.  But if a power
+** failure occurred while the journal was being written, it could be the
+** case that the size of the journal file had already been increased but
+** the extra entries had not yet made it safely to disk.  In such a case,
+** the value of nRec computed from the file size would be too large.  For
+** that reason, we always use the nRec value in the header.
+**
+** If the nRec value is 0xffffffff it means that nRec should be computed
+** from the file size.  This value is used when the user selects the
+** no-sync option for the journal.  A power failure could lead to corruption
+** in this case.  But for things like temporary table (which will be
+** deleted when the power is restored) we don't care.  
+**
+** If the file opened as the journal file is not a well-formed
+** journal file then all pages up to the first corrupted page are rolled
+** back (or no pages if the journal header is corrupted). The journal file
+** is then deleted and SQLITE_OK returned, just as if no corruption had
+** been encountered.
+**
+** If an I/O or malloc() error occurs, the journal-file is not deleted
+** and an error code is returned.
+*/
+static int pager_playback(Pager *pPager, int isHot){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  i64 szJ;                 /* Size of the journal file in bytes */
+  u32 nRec;                /* Number of Records in the journal */
+  int i;                   /* Loop counter */
+  Pgno mxPg = 0;           /* Size of the original file in pages */
+  int rc;                  /* Result code of a subroutine */
+  int res = 0;             /* Value returned by sqlite3OsAccess() */
+  char *zMaster = 0;       /* Name of master journal file if any */
+
+  /* Figure out how many records are in the journal.  Abort early if
+  ** the journal is empty.
+  */
+  assert( pPager->journalOpen );
+  rc = sqlite3OsFileSize(pPager->jfd, &szJ);
+  if( rc!=SQLITE_OK || szJ==0 ){
+    goto end_playback;
+  }
+
+  /* Read the master journal name from the journal, if it is present.
+  ** If a master journal file name is specified, but the file is not
+  ** present on disk, then the journal is not hot and does not need to be
+  ** played back.
+  */
+  zMaster = pPager->pTmpSpace;
+  rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
+  if( rc!=SQLITE_OK || (zMaster[0] 
+   && (res=sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS))==0 ) 
+  ){
+    zMaster = 0;
+    goto end_playback;
+  }
+  zMaster = 0;
+  if( res<0 ){
+    rc = SQLITE_IOERR_NOMEM;
+    goto end_playback;
+  }
+  pPager->journalOff = 0;
+
+  /* This loop terminates either when the readJournalHdr() call returns
+  ** SQLITE_DONE or an IO error occurs. */
+  while( 1 ){
+
+    /* Read the next journal header from the journal file.  If there are
+    ** not enough bytes left in the journal file for a complete header, or
+    ** it is corrupted, then a process must of failed while writing it.
+    ** This indicates nothing more needs to be rolled back.
+    */
+    rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
+    if( rc!=SQLITE_OK ){ 
+      if( rc==SQLITE_DONE ){
+        rc = SQLITE_OK;
+      }
+      goto end_playback;
+    }
+
+    /* If nRec is 0xffffffff, then this journal was created by a process
+    ** working in no-sync mode. This means that the rest of the journal
+    ** file consists of pages, there are no more journal headers. Compute
+    ** the value of nRec based on this assumption.
+    */
+    if( nRec==0xffffffff ){
+      assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
+      nRec = (szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager);
+    }
+
+    /* If nRec is 0 and this rollback is of a transaction created by this
+    ** process and if this is the final header in the journal, then it means
+    ** that this part of the journal was being filled but has not yet been
+    ** synced to disk.  Compute the number of pages based on the remaining
+    ** size of the file.
+    **
+    ** The third term of the test was added to fix ticket #2565.
+    */
+    if( nRec==0 && !isHot &&
+        pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
+      nRec = (szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager);
+    }
+
+    /* If this is the first header read from the journal, truncate the
+    ** database file back to its original size.
+    */
+    if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
+      rc = pager_truncate(pPager, mxPg);
+      if( rc!=SQLITE_OK ){
+        goto end_playback;
+      }
+    }
+
+    /* Copy original pages out of the journal and back into the database file.
+    */
+    for(i=0; i<nRec; i++){
+      rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ){
+          rc = SQLITE_OK;
+          pPager->journalOff = szJ;
+          break;
+        }else{
+          goto end_playback;
+        }
+      }
+    }
+  }
+  /*NOTREACHED*/
+  assert( 0 );
+
+end_playback:
+  if( rc==SQLITE_OK ){
+    zMaster = pPager->pTmpSpace;
+    rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
+  }
+  if( rc==SQLITE_OK ){
+    rc = pager_end_transaction(pPager, zMaster[0]!='\0');
+  }
+  if( rc==SQLITE_OK && zMaster[0] ){
+    /* If there was a master journal and this routine will return success,
+    ** see if it is possible to delete the master journal.
+    */
+    rc = pager_delmaster(pPager, zMaster);
+  }
+
+  /* The Pager.sectorSize variable may have been updated while rolling
+  ** back a journal created by a process with a different sector size
+  ** value. Reset it to the correct value for this process.
+  */
+  setSectorSize(pPager);
+  return rc;
+}
+
+/*
+** Playback the statement journal.
+**
+** This is similar to playing back the transaction journal but with
+** a few extra twists.
+**
+**    (1)  The number of pages in the database file at the start of
+**         the statement is stored in pPager->stmtSize, not in the
+**         journal file itself.
+**
+**    (2)  In addition to playing back the statement journal, also
+**         playback all pages of the transaction journal beginning
+**         at offset pPager->stmtJSize.
+*/
+static int pager_stmt_playback(Pager *pPager){
+  i64 szJ;                 /* Size of the full journal */
+  i64 hdrOff;
+  int nRec;                /* Number of Records */
+  int i;                   /* Loop counter */
+  int rc;
+
+  szJ = pPager->journalOff;
+
+  /* Set hdrOff to be the offset just after the end of the last journal
+  ** page written before the first journal-header for this statement
+  ** transaction was written, or the end of the file if no journal
+  ** header was written.
+  */
+  hdrOff = pPager->stmtHdrOff;
+  assert( pPager->fullSync || !hdrOff );
+  if( !hdrOff ){
+    hdrOff = szJ;
+  }
+  
+  /* Truncate the database back to its original size.
+  */
+  rc = pager_truncate(pPager, pPager->stmtSize);
+  assert( pPager->state>=PAGER_SHARED );
+
+  /* Figure out how many records are in the statement journal.
+  */
+  assert( pPager->stmtInUse && pPager->journalOpen );
+  nRec = pPager->stmtNRec;
+  
+  /* Copy original pages out of the statement journal and back into the
+  ** database file.  Note that the statement journal omits checksums from
+  ** each record since power-failure recovery is not important to statement
+  ** journals.
+  */
+  for(i=0; i<nRec; i++){
+    i64 offset = i*(4+pPager->pageSize);
+    rc = pager_playback_one_page(pPager, pPager->stfd, offset, 0);
+    assert( rc!=SQLITE_DONE );
+    if( rc!=SQLITE_OK ) goto end_stmt_playback;
+  }
+
+  /* Now roll some pages back from the transaction journal. Pager.stmtJSize
+  ** was the size of the journal file when this statement was started, so
+  ** everything after that needs to be rolled back, either into the
+  ** database, the memory cache, or both.
+  **
+  ** If it is not zero, then Pager.stmtHdrOff is the offset to the start
+  ** of the first journal header written during this statement transaction.
+  */
+  pPager->journalOff = pPager->stmtJSize;
+  pPager->cksumInit = pPager->stmtCksum;
+  while( pPager->journalOff < hdrOff ){
+    rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
+    assert( rc!=SQLITE_DONE );
+    if( rc!=SQLITE_OK ) goto end_stmt_playback;
+  }
+
+  while( pPager->journalOff < szJ ){
+    u32 nJRec;         /* Number of Journal Records */
+    u32 dummy;
+    rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
+    if( rc!=SQLITE_OK ){
+      assert( rc!=SQLITE_DONE );
+      goto end_stmt_playback;
+    }
+    if( nJRec==0 ){
+      nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
+    }
+    for(i=nJRec-1; i>=0 && pPager->journalOff < szJ; i--){
+      rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
+      assert( rc!=SQLITE_DONE );
+      if( rc!=SQLITE_OK ) goto end_stmt_playback;
+    }
+  }
+
+  pPager->journalOff = szJ;
+  
+end_stmt_playback:
+  if( rc==SQLITE_OK) {
+    pPager->journalOff = szJ;
+    /* pager_reload_cache(pPager); */
+  }
+  return rc;
+}
+
+/*
+** Change the maximum number of in-memory pages that are allowed.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
+  if( mxPage>10 ){
+    pPager->mxPage = mxPage;
+  }else{
+    pPager->mxPage = 10;
+  }
+}
+
+/*
+** Adjust the robustness of the database to damage due to OS crashes
+** or power failures by changing the number of syncs()s when writing
+** the rollback journal.  There are three levels:
+**
+**    OFF       sqlite3OsSync() is never called.  This is the default
+**              for temporary and transient files.
+**
+**    NORMAL    The journal is synced once before writes begin on the
+**              database.  This is normally adequate protection, but
+**              it is theoretically possible, though very unlikely,
+**              that an inopertune power failure could leave the journal
+**              in a state which would cause damage to the database
+**              when it is rolled back.
+**
+**    FULL      The journal is synced twice before writes begin on the
+**              database (with some additional information - the nRec field
+**              of the journal header - being written in between the two
+**              syncs).  If we assume that writing a
+**              single disk sector is atomic, then this mode provides
+**              assurance that the journal will not be corrupted to the
+**              point of causing damage to the database during rollback.
+**
+** Numeric values associated with these states are OFF==1, NORMAL=2,
+** and FULL=3.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int full_fsync){
+  pPager->noSync =  level==1 || pPager->tempFile;
+  pPager->fullSync = level==3 && !pPager->tempFile;
+  pPager->sync_flags = (full_fsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
+  if( pPager->noSync ) pPager->needSync = 0;
+}
+#endif
+
+/*
+** The following global variable is incremented whenever the library
+** attempts to open a temporary file.  This information is used for
+** testing and analysis only.  
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_opentemp_count = 0;
+#endif
+
+/*
+** Open a temporary file. 
+**
+** Write the file descriptor into *fd.  Return SQLITE_OK on success or some
+** other error code if we fail. The OS will automatically delete the temporary
+** file when it is closed.
+*/
+static int sqlite3PagerOpentemp(
+  sqlite3_vfs *pVfs,    /* The virtual file system layer */
+  sqlite3_file *pFile,  /* Write the file descriptor here */
+  char *zFilename,      /* Name of the file.  Might be NULL */
+  int vfsFlags          /* Flags passed through to the VFS */
+){
+  int rc;
+  assert( zFilename!=0 );
+
+#ifdef SQLITE_TEST
+  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
+#endif
+
+  vfsFlags |=  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
+            SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
+  rc = sqlite3OsOpen(pVfs, zFilename, pFile, vfsFlags, 0);
+  assert( rc!=SQLITE_OK || pFile->pMethods );
+  return rc;
+}
+
+/*
+** Create a new page cache and put a pointer to the page cache in *ppPager.
+** The file to be cached need not exist.  The file is not locked until
+** the first call to sqlite3PagerGet() and is only held open until the
+** last page is released using sqlite3PagerUnref().
+**
+** If zFilename is NULL then a randomly-named temporary file is created
+** and used as the file to be cached.  The file will be deleted
+** automatically when it is closed.
+**
+** If zFilename is ":memory:" then all information is held in cache.
+** It is never written to disk.  This can be used to implement an
+** in-memory database.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs *pVfs,       /* The virtual file system to use */
+  Pager **ppPager,         /* Return the Pager structure here */
+  const char *zFilename,   /* Name of the database file to open */
+  int nExtra,              /* Extra bytes append to each in-memory page */
+  int flags,               /* flags controlling this file */
+  int vfsFlags             /* flags passed through to sqlite3_vfs.xOpen() */
+){
+  u8 *pPtr;
+  Pager *pPager = 0;
+  int rc = SQLITE_OK;
+  int i;
+  int tempFile = 0;
+  int memDb = 0;
+  int readOnly = 0;
+  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
+  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
+  int journalFileSize = sqlite3JournalSize(pVfs);
+  int nDefaultPage = SQLITE_DEFAULT_PAGE_SIZE;
+  char *zPathname;
+  int nPathname;
+  char *zStmtJrnl;
+  int nStmtJrnl;
+
+  /* The default return is a NULL pointer */
+  *ppPager = 0;
+
+  /* Compute the full pathname */
+  nPathname = pVfs->mxPathname+1;
+  zPathname = sqlite3_malloc(nPathname*2);
+  if( zPathname==0 ){
+    return SQLITE_NOMEM;
+  }
+  if( zFilename && zFilename[0] ){
+#ifndef SQLITE_OMIT_MEMORYDB
+    if( strcmp(zFilename,":memory:")==0 ){
+      memDb = 1;
+      zPathname[0] = 0;
+    }else
+#endif
+    {
+      rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
+    }
+  }else{
+    rc = sqlite3OsGetTempname(pVfs, nPathname, zPathname);
+  }
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zPathname);
+    return rc;
+  }
+  nPathname = strlen(zPathname);
+
+  /* Put the statement journal in temporary disk space since this is
+  ** sometimes RAM disk or other optimized storage.  Unlikely the main
+  ** main journal file, the statement journal does not need to be 
+  ** colocated with the database nor does it need to be persistent.
+  */
+  zStmtJrnl = &zPathname[nPathname+1];
+  rc = sqlite3OsGetTempname(pVfs, pVfs->mxPathname+1, zStmtJrnl);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zPathname);
+    return rc;
+  }
+  nStmtJrnl = strlen(zStmtJrnl);
+
+  /* Allocate memory for the pager structure */
+  pPager = sqlite3MallocZero(
+    sizeof(*pPager) +           /* Pager structure */
+    journalFileSize +           /* The journal file structure */ 
+    pVfs->szOsFile * 3 +        /* The main db and two journal files */ 
+    3*nPathname + 40 +          /* zFilename, zDirectory, zJournal */
+    nStmtJrnl                   /* zStmtJrnl */
+  );
+  if( !pPager ){
+    sqlite3_free(zPathname);
+    return SQLITE_NOMEM;
+  }
+  pPtr = (u8 *)&pPager[1];
+  pPager->vfsFlags = vfsFlags;
+  pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
+  pPager->stfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*1];
+  pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*2];
+  pPager->zFilename = (char*)&pPtr[pVfs->szOsFile*2+journalFileSize];
+  pPager->zDirectory = &pPager->zFilename[nPathname+1];
+  pPager->zJournal = &pPager->zDirectory[nPathname+1];
+  pPager->zStmtJrnl = &pPager->zJournal[nPathname+10];
+  pPager->pVfs = pVfs;
+  memcpy(pPager->zFilename, zPathname, nPathname+1);
+  memcpy(pPager->zStmtJrnl, zStmtJrnl, nStmtJrnl+1);
+  sqlite3_free(zPathname);
+
+  /* Open the pager file.
+  */
+  if( zFilename && zFilename[0] && !memDb ){
+    if( nPathname>(pVfs->mxPathname - sizeof("-journal")) ){
+      rc = SQLITE_CANTOPEN;
+    }else{
+      int fout = 0;
+      rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd,
+                         pPager->vfsFlags, &fout);
+      readOnly = (fout&SQLITE_OPEN_READONLY);
+
+      /* If the file was successfully opened for read/write access,
+      ** choose a default page size in case we have to create the
+      ** database file. The default page size is the maximum of:
+      **
+      **    + SQLITE_DEFAULT_PAGE_SIZE,
+      **    + The value returned by sqlite3OsSectorSize()
+      **    + The largest page size that can be written atomically.
+      */
+      if( rc==SQLITE_OK && !readOnly ){
+        int iSectorSize = sqlite3OsSectorSize(pPager->fd);
+        if( nDefaultPage<iSectorSize ){
+          nDefaultPage = iSectorSize;
+        }
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+        {
+          int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+          int ii;
+          assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+          assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+          assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
+          for(ii=nDefaultPage; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
+            if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ) nDefaultPage = ii;
+          }
+        }
+#endif
+        if( nDefaultPage>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
+          nDefaultPage = SQLITE_MAX_DEFAULT_PAGE_SIZE;
+        }
+      }
+    }
+  }else if( !memDb ){
+    /* If a temporary file is requested, it is not opened immediately.
+    ** In this case we accept the default page size and delay actually
+    ** opening the file until the first call to OsWrite().
+    */ 
+    tempFile = 1;
+    pPager->state = PAGER_EXCLUSIVE;
+  }
+
+  if( pPager && rc==SQLITE_OK ){
+    pPager->pTmpSpace = sqlite3MallocZero(nDefaultPage);
+  }
+
+  /* If an error occured in either of the blocks above.
+  ** Free the Pager structure and close the file.
+  ** Since the pager is not allocated there is no need to set 
+  ** any Pager.errMask variables.
+  */
+  if( !pPager || !pPager->pTmpSpace ){
+    sqlite3OsClose(pPager->fd);
+    sqlite3_free(pPager);
+    return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
+  }
+
+  PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename);
+  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
+
+  /* Fill in Pager.zDirectory[] */
+  memcpy(pPager->zDirectory, pPager->zFilename, nPathname+1);
+  for(i=strlen(pPager->zDirectory); i>0 && pPager->zDirectory[i-1]!='/'; i--){}
+  if( i>0 ) pPager->zDirectory[i-1] = 0;
+
+  /* Fill in Pager.zJournal[] */
+  memcpy(pPager->zJournal, pPager->zFilename, nPathname);
+  memcpy(&pPager->zJournal[nPathname], "-journal", 9);
+
+  /* pPager->journalOpen = 0; */
+  pPager->useJournal = useJournal && !memDb;
+  pPager->noReadlock = noReadlock && readOnly;
+  /* pPager->stmtOpen = 0; */
+  /* pPager->stmtInUse = 0; */
+  /* pPager->nRef = 0; */
+  pPager->dbSize = memDb-1;
+  pPager->pageSize = nDefaultPage;
+  /* pPager->stmtSize = 0; */
+  /* pPager->stmtJSize = 0; */
+  /* pPager->nPage = 0; */
+  pPager->mxPage = 100;
+  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
+  /* pPager->state = PAGER_UNLOCK; */
+  assert( pPager->state == (tempFile ? PAGER_EXCLUSIVE : PAGER_UNLOCK) );
+  /* pPager->errMask = 0; */
+  pPager->tempFile = tempFile;
+  assert( tempFile==PAGER_LOCKINGMODE_NORMAL 
+          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
+  pPager->exclusiveMode = tempFile; 
+  pPager->memDb = memDb;
+  pPager->readOnly = readOnly;
+  /* pPager->needSync = 0; */
+  pPager->noSync = pPager->tempFile || !useJournal;
+  pPager->fullSync = (pPager->noSync?0:1);
+  pPager->sync_flags = SQLITE_SYNC_NORMAL;
+  /* pPager->pFirst = 0; */
+  /* pPager->pFirstSynced = 0; */
+  /* pPager->pLast = 0; */
+  pPager->nExtra = FORCE_ALIGNMENT(nExtra);
+  assert(pPager->fd->pMethods||memDb||tempFile);
+  if( !memDb ){
+    setSectorSize(pPager);
+  }
+  /* pPager->pBusyHandler = 0; */
+  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
+  *ppPager = pPager;
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  pPager->iInUseMM = 0;
+  pPager->iInUseDB = 0;
+  if( !memDb ){
+#ifndef SQLITE_MUTEX_NOOP
+    sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
+#endif
+    sqlite3_mutex_enter(mutex);
+    pPager->pNext = sqlite3PagerList;
+    if( sqlite3PagerList ){
+      assert( sqlite3PagerList->pPrev==0 );
+      sqlite3PagerList->pPrev = pPager;
+    }
+    pPager->pPrev = 0;
+    sqlite3PagerList = pPager;
+    sqlite3_mutex_leave(mutex);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Set the busy handler function.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager *pPager, BusyHandler *pBusyHandler){
+  pPager->pBusyHandler = pBusyHandler;
+}
+
+/*
+** Set the destructor for this pager.  If not NULL, the destructor is called
+** when the reference count on each page reaches zero.  The destructor can
+** be used to clean up information in the extra segment appended to each page.
+**
+** The destructor is not called as a result sqlite3PagerClose().  
+** Destructors are only called by sqlite3PagerUnref().
+*/
+SQLITE_PRIVATE void sqlite3PagerSetDestructor(Pager *pPager, void (*xDesc)(DbPage*,int)){
+  pPager->xDestructor = xDesc;
+}
+
+/*
+** Set the reinitializer for this pager.  If not NULL, the reinitializer
+** is called when the content of a page in cache is restored to its original
+** value as a result of a rollback.  The callback gives higher-level code
+** an opportunity to restore the EXTRA section to agree with the restored
+** page data.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetReiniter(Pager *pPager, void (*xReinit)(DbPage*,int)){
+  pPager->xReiniter = xReinit;
+}
+
+/*
+** Set the page size to *pPageSize. If the suggest new page size is
+** inappropriate, then an alternative page size is set to that
+** value before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize){
+  int rc = SQLITE_OK;
+  u16 pageSize = *pPageSize;
+  assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
+  if( pageSize && pageSize!=pPager->pageSize 
+   && !pPager->memDb && pPager->nRef==0 
+  ){
+    char *pNew = (char *)sqlite3_malloc(pageSize);
+    if( !pNew ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pagerEnter(pPager);
+      pager_reset(pPager);
+      pPager->pageSize = pageSize;
+      setSectorSize(pPager);
+      sqlite3_free(pPager->pTmpSpace);
+      pPager->pTmpSpace = pNew;
+      pagerLeave(pPager);
+    }
+  }
+  *pPageSize = pPager->pageSize;
+  return rc;
+}
+
+/*
+** Return a pointer to the "temporary page" buffer held internally
+** by the pager.  This is a buffer that is big enough to hold the
+** entire content of a database page.  This buffer is used internally
+** during rollback and will be overwritten whenever a rollback
+** occurs.  But other modules are free to use it too, as long as
+** no rollbacks are happening.
+*/
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager *pPager){
+  return pPager->pTmpSpace;
+}
+
+/*
+** Attempt to set the maximum database page count if mxPage is positive. 
+** Make no changes if mxPage is zero or negative.  And never reduce the
+** maximum page count below the current size of the database.
+**
+** Regardless of mxPage, return the current maximum page count.
+*/
+SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
+  if( mxPage>0 ){
+    pPager->mxPgno = mxPage;
+  }
+  sqlite3PagerPagecount(pPager);
+  return pPager->mxPgno;
+}
+
+/*
+** The following set of routines are used to disable the simulated
+** I/O error mechanism.  These routines are used to avoid simulated
+** errors in places where we do not care about errors.
+**
+** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
+** and generate no code.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API extern int sqlite3_io_error_pending;
+SQLITE_API extern int sqlite3_io_error_hit;
+static int saved_cnt;
+void disable_simulated_io_errors(void){
+  saved_cnt = sqlite3_io_error_pending;
+  sqlite3_io_error_pending = -1;
+}
+void enable_simulated_io_errors(void){
+  sqlite3_io_error_pending = saved_cnt;
+}
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+/*
+** Read the first N bytes from the beginning of the file into memory
+** that pDest points to. 
+**
+** No error checking is done. The rational for this is that this function 
+** may be called even if the file does not exist or contain a header. In 
+** these cases sqlite3OsRead() will return an error, to which the correct 
+** response is to zero the memory at pDest and continue.  A real IO error 
+** will presumably recur and be picked up later (Todo: Think about this).
+*/
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
+  int rc = SQLITE_OK;
+  memset(pDest, 0, N);
+  assert(MEMDB||pPager->fd->pMethods||pPager->tempFile);
+  if( pPager->fd->pMethods ){
+    IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
+    rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the total number of pages in the disk file associated with
+** pPager. 
+**
+** If the PENDING_BYTE lies on the page directly after the end of the
+** file, then consider this page part of the file too. For example, if
+** PENDING_BYTE is byte 4096 (the first byte of page 5) and the size of the
+** file is 4096 bytes, 5 is returned instead of 4.
+*/
+SQLITE_PRIVATE int sqlite3PagerPagecount(Pager *pPager){
+  i64 n = 0;
+  int rc;
+  assert( pPager!=0 );
+  if( pPager->errCode ){
+    return -1;
+  }
+  if( pPager->dbSize>=0 ){
+    n = pPager->dbSize;
+  } else {
+    assert(pPager->fd->pMethods||pPager->tempFile);
+    if( (pPager->fd->pMethods)
+     && (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
+      pPager->nRef++;
+      pager_error(pPager, rc);
+      pPager->nRef--;
+      return -1;
+    }
+    if( n>0 && n<pPager->pageSize ){
+      n = 1;
+    }else{
+      n /= pPager->pageSize;
+    }
+    if( pPager->state!=PAGER_UNLOCK ){
+      pPager->dbSize = n;
+    }
+  }
+  if( n==(PENDING_BYTE/pPager->pageSize) ){
+    n++;
+  }
+  if( n>pPager->mxPgno ){
+    pPager->mxPgno = n;
+  }
+  return n;
+}
+
+
+#ifndef SQLITE_OMIT_MEMORYDB
+/*
+** Clear a PgHistory block
+*/
+static void clearHistory(PgHistory *pHist){
+  sqlite3_free(pHist->pOrig);
+  sqlite3_free(pHist->pStmt);
+  pHist->pOrig = 0;
+  pHist->pStmt = 0;
+}
+#else
+#define clearHistory(x)
+#endif
+
+/*
+** Forward declaration
+*/
+static int syncJournal(Pager*);
+
+/*
+** Unlink pPg from its hash chain. Also set the page number to 0 to indicate
+** that the page is not part of any hash chain. This is required because the
+** sqlite3PagerMovepage() routine can leave a page in the 
+** pNextFree/pPrevFree list that is not a part of any hash-chain.
+*/
+static void unlinkHashChain(Pager *pPager, PgHdr *pPg){
+  if( pPg->pgno==0 ){
+    assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
+    return;
+  }
+  if( pPg->pNextHash ){
+    pPg->pNextHash->pPrevHash = pPg->pPrevHash;
+  }
+  if( pPg->pPrevHash ){
+    assert( pPager->aHash[pPg->pgno & (pPager->nHash-1)]!=pPg );
+    pPg->pPrevHash->pNextHash = pPg->pNextHash;
+  }else{
+    int h = pPg->pgno & (pPager->nHash-1);
+    pPager->aHash[h] = pPg->pNextHash;
+  }
+  if( MEMDB ){
+    clearHistory(PGHDR_TO_HIST(pPg, pPager));
+  }
+  pPg->pgno = 0;
+  pPg->pNextHash = pPg->pPrevHash = 0;
+}
+
+/*
+** Unlink a page from the free list (the list of all pages where nRef==0)
+** and from its hash collision chain.
+*/
+static void unlinkPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+
+  /* Unlink from free page list */
+  lruListRemove(pPg);
+
+  /* Unlink from the pgno hash table */
+  unlinkHashChain(pPager, pPg);
+}
+
+/*
+** This routine is used to truncate the cache when a database
+** is truncated.  Drop from the cache all pages whose pgno is
+** larger than pPager->dbSize and is unreferenced.
+**
+** Referenced pages larger than pPager->dbSize are zeroed.
+**
+** Actually, at the point this routine is called, it would be
+** an error to have a referenced page.  But rather than delete
+** that page and guarantee a subsequent segfault, it seems better
+** to zero it and hope that we error out sanely.
+*/
+static void pager_truncate_cache(Pager *pPager){
+  PgHdr *pPg;
+  PgHdr **ppPg;
+  int dbSize = pPager->dbSize;
+
+  ppPg = &pPager->pAll;
+  while( (pPg = *ppPg)!=0 ){
+    if( pPg->pgno<=dbSize ){
+      ppPg = &pPg->pNextAll;
+    }else if( pPg->nRef>0 ){
+      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
+      ppPg = &pPg->pNextAll;
+    }else{
+      *ppPg = pPg->pNextAll;
+      IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
+      PAGER_INCR(sqlite3_pager_pgfree_count);
+      unlinkPage(pPg);
+      makeClean(pPg);
+      sqlite3_free(pPg->pData);
+      sqlite3_free(pPg);
+      pPager->nPage--;
+    }
+  }
+}
+
+/*
+** Try to obtain a lock on a file.  Invoke the busy callback if the lock
+** is currently not available.  Repeat until the busy callback returns
+** false or until the lock succeeds.
+**
+** Return SQLITE_OK on success and an error code if we cannot obtain
+** the lock.
+*/
+static int pager_wait_on_lock(Pager *pPager, int locktype){
+  int rc;
+
+  /* The OS lock values must be the same as the Pager lock values */
+  assert( PAGER_SHARED==SHARED_LOCK );
+  assert( PAGER_RESERVED==RESERVED_LOCK );
+  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
+
+  /* If the file is currently unlocked then the size must be unknown */
+  assert( pPager->state>=PAGER_SHARED || pPager->dbSize<0 || MEMDB );
+
+  if( pPager->state>=locktype ){
+    rc = SQLITE_OK;
+  }else{
+    if( pPager->pBusyHandler ) pPager->pBusyHandler->nBusy = 0;
+    do {
+      rc = sqlite3OsLock(pPager->fd, locktype);
+    }while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
+    if( rc==SQLITE_OK ){
+      pPager->state = locktype;
+      IOTRACE(("LOCK %p %d\n", pPager, locktype))
+    }
+  }
+  return rc;
+}
+
+/*
+** Truncate the file to the number of pages specified.
+*/
+SQLITE_PRIVATE int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
+  int rc;
+  assert( pPager->state>=PAGER_SHARED || MEMDB );
+  sqlite3PagerPagecount(pPager);
+  if( pPager->errCode ){
+    rc = pPager->errCode;
+    return rc;
+  }
+  if( nPage>=(unsigned)pPager->dbSize ){
+    return SQLITE_OK;
+  }
+  if( MEMDB ){
+    pPager->dbSize = nPage;
+    pager_truncate_cache(pPager);
+    return SQLITE_OK;
+  }
+  pagerEnter(pPager);
+  rc = syncJournal(pPager);
+  pagerLeave(pPager);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Get an exclusive lock on the database before truncating. */
+  pagerEnter(pPager);
+  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+  pagerLeave(pPager);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  rc = pager_truncate(pPager, nPage);
+  return rc;
+}
+
+/*
+** Shutdown the page cache.  Free all memory and close all files.
+**
+** If a transaction was in progress when this routine is called, that
+** transaction is rolled back.  All outstanding pages are invalidated
+** and their memory is freed.  Any attempt to use a page associated
+** with this page cache after this function returns will likely
+** result in a coredump.
+**
+** This function always succeeds. If a transaction is active an attempt
+** is made to roll it back. If an error occurs during the rollback 
+** a hot journal may be left in the filesystem but no error is returned
+** to the caller.
+*/
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( !MEMDB ){
+#ifndef SQLITE_MUTEX_NOOP
+    sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
+#endif
+    sqlite3_mutex_enter(mutex);
+    if( pPager->pPrev ){
+      pPager->pPrev->pNext = pPager->pNext;
+    }else{
+      sqlite3PagerList = pPager->pNext;
+    }
+    if( pPager->pNext ){
+      pPager->pNext->pPrev = pPager->pPrev;
+    }
+    sqlite3_mutex_leave(mutex);
+  }
+#endif
+
+  disable_simulated_io_errors();
+  sqlite3FaultBeginBenign(-1);
+  pPager->errCode = 0;
+  pPager->exclusiveMode = 0;
+  pager_reset(pPager);
+  pagerUnlockAndRollback(pPager);
+  enable_simulated_io_errors();
+  sqlite3FaultEndBenign(-1);
+  PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
+  IOTRACE(("CLOSE %p\n", pPager))
+  if( pPager->journalOpen ){
+    sqlite3OsClose(pPager->jfd);
+  }
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  if( pPager->stmtOpen ){
+    sqlite3OsClose(pPager->stfd);
+  }
+  sqlite3OsClose(pPager->fd);
+  /* Temp files are automatically deleted by the OS
+  ** if( pPager->tempFile ){
+  **   sqlite3OsDelete(pPager->zFilename);
+  ** }
+  */
+
+  sqlite3_free(pPager->aHash);
+  sqlite3_free(pPager->pTmpSpace);
+  sqlite3_free(pPager);
+  return SQLITE_OK;
+}
+
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+/*
+** Return the page number for the given page data.
+*/
+SQLITE_PRIVATE Pgno sqlite3PagerPagenumber(DbPage *p){
+  return p->pgno;
+}
+#endif
+
+/*
+** The page_ref() function increments the reference count for a page.
+** If the page is currently on the freelist (the reference count is zero) then
+** remove it from the freelist.
+**
+** For non-test systems, page_ref() is a macro that calls _page_ref()
+** online of the reference count is zero.  For test systems, page_ref()
+** is a real function so that we can set breakpoints and trace it.
+*/
+static void _page_ref(PgHdr *pPg){
+  if( pPg->nRef==0 ){
+    /* The page is currently on the freelist.  Remove it. */
+    lruListRemove(pPg);
+    pPg->pPager->nRef++;
+  }
+  pPg->nRef++;
+}
+#ifdef SQLITE_DEBUG
+  static void page_ref(PgHdr *pPg){
+    if( pPg->nRef==0 ){
+      _page_ref(pPg);
+    }else{
+      pPg->nRef++;
+    }
+  }
+#else
+# define page_ref(P)   ((P)->nRef==0?_page_ref(P):(void)(P)->nRef++)
+#endif
+
+/*
+** Increment the reference count for a page.  The input pointer is
+** a reference to the page data.
+*/
+SQLITE_PRIVATE int sqlite3PagerRef(DbPage *pPg){
+  pagerEnter(pPg->pPager);
+  page_ref(pPg);
+  pagerLeave(pPg->pPager);
+  return SQLITE_OK;
+}
+
+/*
+** Sync the journal.  In other words, make sure all the pages that have
+** been written to the journal have actually reached the surface of the
+** disk.  It is not safe to modify the original database file until after
+** the journal has been synced.  If the original database is modified before
+** the journal is synced and a power failure occurs, the unsynced journal
+** data would be lost and we would be unable to completely rollback the
+** database changes.  Database corruption would occur.
+** 
+** This routine also updates the nRec field in the header of the journal.
+** (See comments on the pager_playback() routine for additional information.)
+** If the sync mode is FULL, two syncs will occur.  First the whole journal
+** is synced, then the nRec field is updated, then a second sync occurs.
+**
+** For temporary databases, we do not care if we are able to rollback
+** after a power failure, so no sync occurs.
+**
+** If the IOCAP_SEQUENTIAL flag is set for the persistent media on which
+** the database is stored, then OsSync() is never called on the journal
+** file. In this case all that is required is to update the nRec field in
+** the journal header.
+**
+** This routine clears the needSync field of every page current held in
+** memory.
+*/
+static int syncJournal(Pager *pPager){
+  PgHdr *pPg;
+  int rc = SQLITE_OK;
+
+
+  /* Sync the journal before modifying the main database
+  ** (assuming there is a journal and it needs to be synced.)
+  */
+  if( pPager->needSync ){
+    if( !pPager->tempFile ){
+      int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      assert( pPager->journalOpen );
+
+      if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        /* Write the nRec value into the journal file header. If in
+        ** full-synchronous mode, sync the journal first. This ensures that
+        ** all data has really hit the disk before nRec is updated to mark
+        ** it as a candidate for rollback.
+        **
+        ** This is not required if the persistent media supports the
+        ** SAFE_APPEND property. Because in this case it is not possible 
+        ** for garbage data to be appended to the file, the nRec field
+        ** is populated with 0xFFFFFFFF when the journal header is written
+        ** and never needs to be updated.
+        */
+        i64 jrnlOff;
+        if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+          PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
+          IOTRACE(("JSYNC %p\n", pPager))
+          rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
+          if( rc!=0 ) return rc;
+        }
+
+        jrnlOff = pPager->journalHdr + sizeof(aJournalMagic);
+        IOTRACE(("JHDR %p %lld %d\n", pPager, jrnlOff, 4));
+        rc = write32bits(pPager->jfd, jrnlOff, pPager->nRec);
+        if( rc ) return rc;
+      }
+      if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+        PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
+        IOTRACE(("JSYNC %p\n", pPager))
+        rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags| 
+          (pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
+        );
+        if( rc!=0 ) return rc;
+      }
+      pPager->journalStarted = 1;
+    }
+    pPager->needSync = 0;
+
+    /* Erase the needSync flag from every page.
+    */
+    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+      pPg->needSync = 0;
+    }
+    lruListSetFirstSynced(pPager);
+  }
+
+#ifndef NDEBUG
+  /* If the Pager.needSync flag is clear then the PgHdr.needSync
+  ** flag must also be clear for all pages.  Verify that this
+  ** invariant is true.
+  */
+  else{
+    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+      assert( pPg->needSync==0 );
+    }
+    assert( pPager->lru.pFirstSynced==pPager->lru.pFirst );
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Merge two lists of pages connected by pDirty and in pgno order.
+** Do not both fixing the pPrevDirty pointers.
+*/
+static PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB){
+  PgHdr result, *pTail;
+  pTail = &result;
+  while( pA && pB ){
+    if( pA->pgno<pB->pgno ){
+      pTail->pDirty = pA;
+      pTail = pA;
+      pA = pA->pDirty;
+    }else{
+      pTail->pDirty = pB;
+      pTail = pB;
+      pB = pB->pDirty;
+    }
+  }
+  if( pA ){
+    pTail->pDirty = pA;
+  }else if( pB ){
+    pTail->pDirty = pB;
+  }else{
+    pTail->pDirty = 0;
+  }
+  return result.pDirty;
+}
+
+/*
+** Sort the list of pages in accending order by pgno.  Pages are
+** connected by pDirty pointers.  The pPrevDirty pointers are
+** corrupted by this sort.
+*/
+#define N_SORT_BUCKET_ALLOC 25
+#define N_SORT_BUCKET       25
+#ifdef SQLITE_TEST
+  int sqlite3_pager_n_sort_bucket = 0;
+  #undef N_SORT_BUCKET
+  #define N_SORT_BUCKET \
+   (sqlite3_pager_n_sort_bucket?sqlite3_pager_n_sort_bucket:N_SORT_BUCKET_ALLOC)
+#endif
+static PgHdr *sort_pagelist(PgHdr *pIn){
+  PgHdr *a[N_SORT_BUCKET_ALLOC], *p;
+  int i;
+  memset(a, 0, sizeof(a));
+  while( pIn ){
+    p = pIn;
+    pIn = p->pDirty;
+    p->pDirty = 0;
+    for(i=0; i<N_SORT_BUCKET-1; i++){
+      if( a[i]==0 ){
+        a[i] = p;
+        break;
+      }else{
+        p = merge_pagelist(a[i], p);
+        a[i] = 0;
+      }
+    }
+    if( i==N_SORT_BUCKET-1 ){
+      /* Coverage: To get here, there need to be 2^(N_SORT_BUCKET) 
+      ** elements in the input list. This is possible, but impractical.
+      ** Testing this line is the point of global variable
+      ** sqlite3_pager_n_sort_bucket.
+      */
+      a[i] = merge_pagelist(a[i], p);
+    }
+  }
+  p = a[0];
+  for(i=1; i<N_SORT_BUCKET; i++){
+    p = merge_pagelist(p, a[i]);
+  }
+  return p;
+}
+
+/*
+** Given a list of pages (connected by the PgHdr.pDirty pointer) write
+** every one of those pages out to the database file and mark them all
+** as clean.
+*/
+static int pager_write_pagelist(PgHdr *pList){
+  Pager *pPager;
+  PgHdr *p;
+  int rc;
+
+  if( pList==0 ) return SQLITE_OK;
+  pPager = pList->pPager;
+
+  /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
+  ** database file. If there is already an EXCLUSIVE lock, the following
+  ** calls to sqlite3OsLock() are no-ops.
+  **
+  ** Moving the lock from RESERVED to EXCLUSIVE actually involves going
+  ** through an intermediate state PENDING.   A PENDING lock prevents new
+  ** readers from attaching to the database but is unsufficient for us to
+  ** write.  The idea of a PENDING lock is to prevent new readers from
+  ** coming in while we wait for existing readers to clear.
+  **
+  ** While the pager is in the RESERVED state, the original database file
+  ** is unchanged and we can rollback without having to playback the
+  ** journal into the original database file.  Once we transition to
+  ** EXCLUSIVE, it means the database file has been changed and any rollback
+  ** will require a journal playback.
+  */
+  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  pList = sort_pagelist(pList);
+  for(p=pList; p; p=p->pDirty){
+    assert( p->dirty );
+    p->dirty = 0;
+  }
+  while( pList ){
+
+    /* If the file has not yet been opened, open it now. */
+    if( !pPager->fd->pMethods ){
+      assert(pPager->tempFile);
+      rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->fd, pPager->zFilename,
+                                pPager->vfsFlags);
+      if( rc ) return rc;
+    }
+
+    /* If there are dirty pages in the page cache with page numbers greater
+    ** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
+    ** make the file smaller (presumably by auto-vacuum code). Do not write
+    ** any such pages to the file.
+    */
+    if( pList->pgno<=pPager->dbSize ){
+      i64 offset = (pList->pgno-1)*(i64)pPager->pageSize;
+      char *pData = CODEC2(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
+      PAGERTRACE4("STORE %d page %d hash(%08x)\n",
+                   PAGERID(pPager), pList->pgno, pager_pagehash(pList));
+      IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno));
+      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
+      PAGER_INCR(sqlite3_pager_writedb_count);
+      PAGER_INCR(pPager->nWrite);
+      if( pList->pgno==1 ){
+        memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
+      }
+    }
+#ifndef NDEBUG
+    else{
+      PAGERTRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
+    }
+#endif
+    if( rc ) return rc;
+#ifdef SQLITE_CHECK_PAGES
+    pList->pageHash = pager_pagehash(pList);
+#endif
+    pList = pList->pDirty;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Collect every dirty page into a dirty list and
+** return a pointer to the head of that list.  All pages are
+** collected even if they are still in use.
+*/
+static PgHdr *pager_get_all_dirty_pages(Pager *pPager){
+
+#ifndef NDEBUG
+  /* Verify the sanity of the dirty list when we are running
+  ** in debugging mode.  This is expensive, so do not
+  ** do this on a normal build. */
+  int n1 = 0;
+  int n2 = 0;
+  PgHdr *p;
+  for(p=pPager->pAll; p; p=p->pNextAll){ if( p->dirty ) n1++; }
+  for(p=pPager->pDirty; p; p=p->pDirty){ n2++; }
+  assert( n1==n2 );
+#endif
+
+  return pPager->pDirty;
+}
+
+/*
+** Return 1 if there is a hot journal on the given pager.
+** A hot journal is one that needs to be played back.
+**
+** If the current size of the database file is 0 but a journal file
+** exists, that is probably an old journal left over from a prior
+** database with the same name.  Just delete the journal.
+**
+** Return negative if unable to determine the status of the journal.
+**
+** This routine does not open the journal file to examine its
+** content.  Hence, the journal might contain the name of a master
+** journal file that has been deleted, and hence not be hot.  Or
+** the header of the journal might be zeroed out.  This routine
+** does not discover these cases of a non-hot journal - if the
+** journal file exists and is not empty this routine assumes it
+** is hot.  The pager_playback() routine will discover that the
+** journal file is not really hot and will no-op.
+*/
+static int hasHotJournal(Pager *pPager){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  int rc;
+  if( !pPager->useJournal ) return 0;
+  if( !pPager->fd->pMethods ) return 0;
+  rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS);
+  if( rc<=0 ){
+    return rc;
+  }
+  if( sqlite3OsCheckReservedLock(pPager->fd) ){
+    return 0;
+  }
+  if( sqlite3PagerPagecount(pPager)==0 ){
+    sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Try to find a page in the cache that can be recycled. 
+**
+** This routine may return SQLITE_IOERR, SQLITE_FULL or SQLITE_OK. It 
+** does not set the pPager->errCode variable.
+*/
+static int pager_recycle(Pager *pPager, PgHdr **ppPg){
+  PgHdr *pPg;
+  *ppPg = 0;
+
+  /* It is illegal to call this function unless the pager object
+  ** pointed to by pPager has at least one free page (page with nRef==0).
+  */ 
+  assert(!MEMDB);
+  assert(pPager->lru.pFirst);
+
+  /* Find a page to recycle.  Try to locate a page that does not
+  ** require us to do an fsync() on the journal.
+  */
+  pPg = pPager->lru.pFirstSynced;
+
+  /* If we could not find a page that does not require an fsync()
+  ** on the journal file then fsync the journal file.  This is a
+  ** very slow operation, so we work hard to avoid it.  But sometimes
+  ** it can't be helped.
+  */
+  if( pPg==0 && pPager->lru.pFirst){
+    int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+    int rc = syncJournal(pPager);
+    if( rc!=0 ){
+      return rc;
+    }
+    if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+      /* If in full-sync mode, write a new journal header into the
+      ** journal file. This is done to avoid ever modifying a journal
+      ** header that is involved in the rollback of pages that have
+      ** already been written to the database (in case the header is
+      ** trashed when the nRec field is updated).
+      */
+      pPager->nRec = 0;
+      assert( pPager->journalOff > 0 );
+      assert( pPager->doNotSync==0 );
+      rc = writeJournalHdr(pPager);
+      if( rc!=0 ){
+        return rc;
+      }
+    }
+    pPg = pPager->lru.pFirst;
+  }
+
+  assert( pPg->nRef==0 );
+
+  /* Write the page to the database file if it is dirty.
+  */
+  if( pPg->dirty ){
+    int rc;
+    assert( pPg->needSync==0 );
+    makeClean(pPg);
+    pPg->dirty = 1;
+    pPg->pDirty = 0;
+    rc = pager_write_pagelist( pPg );
+    pPg->dirty = 0;
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }
+  assert( pPg->dirty==0 );
+
+  /* If the page we are recycling is marked as alwaysRollback, then
+  ** set the global alwaysRollback flag, thus disabling the
+  ** sqlite3PagerDontRollback() optimization for the rest of this transaction.
+  ** It is necessary to do this because the page marked alwaysRollback
+  ** might be reloaded at a later time but at that point we won't remember
+  ** that is was marked alwaysRollback.  This means that all pages must
+  ** be marked as alwaysRollback from here on out.
+  */
+  if( pPg->alwaysRollback ){
+    IOTRACE(("ALWAYS_ROLLBACK %p\n", pPager))
+    pPager->alwaysRollback = 1;
+  }
+
+  /* Unlink the old page from the free list and the hash table
+  */
+  unlinkPage(pPg);
+  assert( pPg->pgno==0 );
+
+  *ppPg = pPg;
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** This function is called to free superfluous dynamically allocated memory
+** held by the pager system. Memory in use by any SQLite pager allocated
+** by the current thread may be sqlite3_free()ed.
+**
+** nReq is the number of bytes of memory required. Once this much has
+** been released, the function returns. The return value is the total number 
+** of bytes of memory released.
+*/
+SQLITE_PRIVATE int sqlite3PagerReleaseMemory(int nReq){
+  int nReleased = 0;          /* Bytes of memory released so far */
+  Pager *pPager;              /* For looping over pagers */
+  BusyHandler *savedBusy;     /* Saved copy of the busy handler */
+  int rc = SQLITE_OK;
+
+  /* Acquire the memory-management mutex
+  */
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex;       /* The MEM2 mutex */
+  mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
+#endif
+  sqlite3_mutex_enter(mutex);
+
+  /* Signal all database connections that memory management wants
+  ** to have access to the pagers.
+  */
+  for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
+     pPager->iInUseMM = 1;
+  }
+
+  while( rc==SQLITE_OK && (nReq<0 || nReleased<nReq) ){
+    PgHdr *pPg;
+    PgHdr *pRecycled;
+ 
+    /* Try to find a page to recycle that does not require a sync(). If
+    ** this is not possible, find one that does require a sync().
+    */
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+    pPg = sqlite3LruPageList.pFirstSynced;
+    while( pPg && (pPg->needSync || pPg->pPager->iInUseDB) ){
+      pPg = pPg->gfree.pNext;
+    }
+    if( !pPg ){
+      pPg = sqlite3LruPageList.pFirst;
+      while( pPg && pPg->pPager->iInUseDB ){
+        pPg = pPg->gfree.pNext;
+      }
+    }
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
+
+    /* If pPg==0, then the block above has failed to find a page to
+    ** recycle. In this case return early - no further memory will
+    ** be released.
+    */
+    if( !pPg ) break;
+
+    pPager = pPg->pPager;
+    assert(!pPg->needSync || pPg==pPager->lru.pFirst);
+    assert(pPg->needSync || pPg==pPager->lru.pFirstSynced);
+  
+    savedBusy = pPager->pBusyHandler;
+    pPager->pBusyHandler = 0;
+    rc = pager_recycle(pPager, &pRecycled);
+    pPager->pBusyHandler = savedBusy;
+    assert(pRecycled==pPg || rc!=SQLITE_OK);
+    if( rc==SQLITE_OK ){
+      /* We've found a page to free. At this point the page has been 
+      ** removed from the page hash-table, free-list and synced-list 
+      ** (pFirstSynced). It is still in the all pages (pAll) list. 
+      ** Remove it from this list before freeing.
+      **
+      ** Todo: Check the Pager.pStmt list to make sure this is Ok. It 
+      ** probably is though.
+      */
+      PgHdr *pTmp;
+      assert( pPg );
+      if( pPg==pPager->pAll ){
+         pPager->pAll = pPg->pNextAll;
+      }else{
+        for( pTmp=pPager->pAll; pTmp->pNextAll!=pPg; pTmp=pTmp->pNextAll ){}
+        pTmp->pNextAll = pPg->pNextAll;
+      }
+      nReleased += (
+          sizeof(*pPg) + pPager->pageSize
+          + sizeof(u32) + pPager->nExtra
+          + MEMDB*sizeof(PgHistory) 
+      );
+      IOTRACE(("PGFREE %p %d *\n", pPager, pPg->pgno));
+      PAGER_INCR(sqlite3_pager_pgfree_count);
+      sqlite3_free(pPg->pData);
+      sqlite3_free(pPg);
+      pPager->nPage--;
+    }else{
+      /* An error occured whilst writing to the database file or 
+      ** journal in pager_recycle(). The error is not returned to the 
+      ** caller of this function. Instead, set the Pager.errCode variable.
+      ** The error will be returned to the user (or users, in the case 
+      ** of a shared pager cache) of the pager for which the error occured.
+      */
+      assert(
+          (rc&0xff)==SQLITE_IOERR ||
+          rc==SQLITE_FULL ||
+          rc==SQLITE_BUSY
+      );
+      assert( pPager->state>=PAGER_RESERVED );
+      pager_error(pPager, rc);
+    }
+  }
+
+  /* Clear the memory management flags and release the mutex
+  */
+  for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
+     pPager->iInUseMM = 0;
+  }
+  sqlite3_mutex_leave(mutex);
+
+  /* Return the number of bytes released
+  */
+  return nReleased;
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
+/*
+** Read the content of page pPg out of the database file.
+*/
+static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
+  int rc;
+  i64 offset;
+  assert( MEMDB==0 );
+  assert(pPager->fd->pMethods||pPager->tempFile);
+  if( !pPager->fd->pMethods ){
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  offset = (pgno-1)*(i64)pPager->pageSize;
+  rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize, offset);
+  PAGER_INCR(sqlite3_pager_readdb_count);
+  PAGER_INCR(pPager->nRead);
+  IOTRACE(("PGIN %p %d\n", pPager, pgno));
+  if( pgno==1 ){
+    memcpy(&pPager->dbFileVers, &((u8*)PGHDR_TO_DATA(pPg))[24],
+                                              sizeof(pPager->dbFileVers));
+  }
+  CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
+  PAGERTRACE4("FETCH %d page %d hash(%08x)\n",
+               PAGERID(pPager), pPg->pgno, pager_pagehash(pPg));
+  return rc;
+}
+
+
+/*
+** This function is called to obtain the shared lock required before
+** data may be read from the pager cache. If the shared lock has already
+** been obtained, this function is a no-op.
+**
+** Immediately after obtaining the shared lock (if required), this function
+** checks for a hot-journal file. If one is found, an emergency rollback
+** is performed immediately.
+*/
+static int pagerSharedLock(Pager *pPager){
+  int rc = SQLITE_OK;
+  int isHot = 0;
+
+  /* If this database is opened for exclusive access, has no outstanding 
+  ** page references and is in an error-state, now is the chance to clear
+  ** the error. Discard the contents of the pager-cache and treat any
+  ** open journal file as a hot-journal.
+  */
+  if( !MEMDB && pPager->exclusiveMode && pPager->nRef==0 && pPager->errCode ){
+    if( pPager->journalOpen ){
+      isHot = 1;
+    }
+    pPager->errCode = SQLITE_OK;
+    pager_reset(pPager);
+  }
+
+  /* If the pager is still in an error state, do not proceed. The error 
+  ** state will be cleared at some point in the future when all page 
+  ** references are dropped and the cache can be discarded.
+  */
+  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
+    return pPager->errCode;
+  }
+
+  if( pPager->state==PAGER_UNLOCK || isHot ){
+    sqlite3_vfs *pVfs = pPager->pVfs;
+    if( !MEMDB ){
+      assert( pPager->nRef==0 );
+      if( !pPager->noReadlock ){
+        rc = pager_wait_on_lock(pPager, SHARED_LOCK);
+        if( rc!=SQLITE_OK ){
+          assert( pPager->state==PAGER_UNLOCK );
+          return pager_error(pPager, rc);
+        }
+        assert( pPager->state>=SHARED_LOCK );
+      }
+  
+      /* If a journal file exists, and there is no RESERVED lock on the
+      ** database file, then it either needs to be played back or deleted.
+      */
+      rc = hasHotJournal(pPager);
+      if( rc<0 ){
+        rc = SQLITE_IOERR_NOMEM;
+        goto failed;
+      }
+      if( rc==1 || isHot ){
+        /* Get an EXCLUSIVE lock on the database file. At this point it is
+        ** important that a RESERVED lock is not obtained on the way to the
+        ** EXCLUSIVE lock. If it were, another process might open the
+        ** database file, detect the RESERVED lock, and conclude that the
+        ** database is safe to read while this process is still rolling it 
+        ** back.
+        ** 
+        ** Because the intermediate RESERVED lock is not requested, the
+        ** second process will get to this point in the code and fail to
+        ** obtain its own EXCLUSIVE lock on the database file.
+        */
+        if( pPager->state<EXCLUSIVE_LOCK ){
+          rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
+          if( rc!=SQLITE_OK ){
+            rc = pager_error(pPager, rc);
+            goto failed;
+          }
+          pPager->state = PAGER_EXCLUSIVE;
+        }
+ 
+        /* Open the journal for read/write access. This is because in 
+        ** exclusive-access mode the file descriptor will be kept open and
+        ** possibly used for a transaction later on. On some systems, the
+        ** OsTruncate() call used in exclusive-access mode also requires
+        ** a read/write file handle.
+        */
+        if( !isHot && pPager->journalOpen==0 ){
+          int res = sqlite3OsAccess(pVfs,pPager->zJournal,SQLITE_ACCESS_EXISTS);
+          if( res==1 ){
+            int fout = 0;
+            int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
+            assert( !pPager->tempFile );
+            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
+            assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
+            if( fout&SQLITE_OPEN_READONLY ){
+              rc = SQLITE_BUSY;
+              sqlite3OsClose(pPager->jfd);
+            }
+          }else if( res==0 ){
+            /* If the journal does not exist, that means some other process
+            ** has already rolled it back */
+            rc = SQLITE_BUSY;
+          }else{
+            /* If sqlite3OsAccess() returns a negative value, that means it
+            ** failed a memory allocation */
+            rc = SQLITE_IOERR_NOMEM;
+          }
+        }
+        if( rc!=SQLITE_OK ){
+          if( rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_UNLOCK 
+           && rc!=SQLITE_IOERR_NOMEM 
+          ){
+            rc = SQLITE_BUSY;
+          }
+          goto failed;
+        }
+        pPager->journalOpen = 1;
+        pPager->journalStarted = 0;
+        pPager->journalOff = 0;
+        pPager->setMaster = 0;
+        pPager->journalHdr = 0;
+ 
+        /* Playback and delete the journal.  Drop the database write
+        ** lock and reacquire the read lock.
+        */
+        rc = pager_playback(pPager, 1);
+        if( rc!=SQLITE_OK ){
+          rc = pager_error(pPager, rc);
+          goto failed;
+        }
+        assert(pPager->state==PAGER_SHARED || 
+            (pPager->exclusiveMode && pPager->state>PAGER_SHARED)
+        );
+      }
+
+      if( pPager->pAll ){
+        /* The shared-lock has just been acquired on the database file
+        ** and there are already pages in the cache (from a previous
+        ** read or write transaction).  Check to see if the database
+        ** has been modified.  If the database has changed, flush the
+        ** cache.
+        **
+        ** Database changes is detected by looking at 15 bytes beginning
+        ** at offset 24 into the file.  The first 4 of these 16 bytes are
+        ** a 32-bit counter that is incremented with each change.  The
+        ** other bytes change randomly with each file change when
+        ** a codec is in use.
+        ** 
+        ** There is a vanishingly small chance that a change will not be 
+        ** detected.  The chance of an undetected change is so small that
+        ** it can be neglected.
+        */
+        char dbFileVers[sizeof(pPager->dbFileVers)];
+        sqlite3PagerPagecount(pPager);
+
+        if( pPager->errCode ){
+          rc = pPager->errCode;
+          goto failed;
+        }
+
+        if( pPager->dbSize>0 ){
+          IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
+          rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
+          if( rc!=SQLITE_OK ){
+            goto failed;
+          }
+        }else{
+          memset(dbFileVers, 0, sizeof(dbFileVers));
+        }
+
+        if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
+          pager_reset(pPager);
+        }
+      }
+    }
+    assert( pPager->exclusiveMode || pPager->state<=PAGER_SHARED );
+    if( pPager->state==PAGER_UNLOCK ){
+      pPager->state = PAGER_SHARED;
+    }
+  }
+
+ failed:
+  if( rc!=SQLITE_OK ){
+    /* pager_unlock() is a no-op for exclusive mode and in-memory databases. */
+    pager_unlock(pPager);
+  }
+  return rc;
+}
+
+/*
+** Allocate a PgHdr object.   Either create a new one or reuse
+** an existing one that is not otherwise in use.
+**
+** A new PgHdr structure is created if any of the following are
+** true:
+**
+**     (1)  We have not exceeded our maximum allocated cache size
+**          as set by the "PRAGMA cache_size" command.
+**
+**     (2)  There are no unused PgHdr objects available at this time.
+**
+**     (3)  This is an in-memory database.
+**
+**     (4)  There are no PgHdr objects that do not require a journal
+**          file sync and a sync of the journal file is currently
+**          prohibited.
+**
+** Otherwise, reuse an existing PgHdr.  In other words, reuse an
+** existing PgHdr if all of the following are true:
+**
+**     (1)  We have reached or exceeded the maximum cache size
+**          allowed by "PRAGMA cache_size".
+**
+**     (2)  There is a PgHdr available with PgHdr->nRef==0
+**
+**     (3)  We are not in an in-memory database
+**
+**     (4)  Either there is an available PgHdr that does not need
+**          to be synced to disk or else disk syncing is currently
+**          allowed.
+*/
+static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
+  int rc = SQLITE_OK;
+  PgHdr *pPg;
+  int nByteHdr;
+
+  /* Create a new PgHdr if any of the four conditions defined 
+  ** above are met: */
+  if( pPager->nPage<pPager->mxPage
+   || pPager->lru.pFirst==0 
+   || MEMDB
+   || (pPager->lru.pFirstSynced==0 && pPager->doNotSync)
+  ){
+    void *pData;
+    if( pPager->nPage>=pPager->nHash ){
+      pager_resize_hash_table(pPager,
+         pPager->nHash<256 ? 256 : pPager->nHash*2);
+      if( pPager->nHash==0 ){
+        rc = SQLITE_NOMEM;
+        goto pager_allocate_out;
+      }
+    }
+    pagerLeave(pPager);
+    nByteHdr = sizeof(*pPg) + sizeof(u32) + pPager->nExtra
+              + MEMDB*sizeof(PgHistory);
+    pPg = sqlite3_malloc( nByteHdr );
+    if( pPg ){
+      pData = sqlite3_malloc( pPager->pageSize );
+      if( pData==0 ){
+        sqlite3_free(pPg);
+        pPg = 0;
+      }
+    }
+    pagerEnter(pPager);
+    if( pPg==0 ){
+      rc = SQLITE_NOMEM;
+      goto pager_allocate_out;
+    }
+    memset(pPg, 0, nByteHdr);
+    pPg->pData = pData;
+    pPg->pPager = pPager;
+    pPg->pNextAll = pPager->pAll;
+    pPager->pAll = pPg;
+    pPager->nPage++;
+  }else{
+    /* Recycle an existing page with a zero ref-count. */
+    rc = pager_recycle(pPager, &pPg);
+    if( rc==SQLITE_BUSY ){
+      rc = SQLITE_IOERR_BLOCKED;
+    }
+    if( rc!=SQLITE_OK ){
+      goto pager_allocate_out;
+    }
+    assert( pPager->state>=SHARED_LOCK );
+    assert(pPg);
+  }
+  *ppPg = pPg;
+
+pager_allocate_out:
+  return rc;
+}
+
+/*
+** Make sure we have the content for a page.  If the page was
+** previously acquired with noContent==1, then the content was
+** just initialized to zeros instead of being read from disk.
+** But now we need the real data off of disk.  So make sure we
+** have it.  Read it in if we do not have it already.
+*/
+static int pager_get_content(PgHdr *pPg){
+  if( pPg->needRead ){
+    int rc = readDbPage(pPg->pPager, pPg, pPg->pgno);
+    if( rc==SQLITE_OK ){
+      pPg->needRead = 0;
+    }else{
+      return rc;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Acquire a page.
+**
+** A read lock on the disk file is obtained when the first page is acquired. 
+** This read lock is dropped when the last page is released.
+**
+** This routine works for any page number greater than 0.  If the database
+** file is smaller than the requested page, then no actual disk
+** read occurs and the memory image of the page is initialized to
+** all zeros.  The extra data appended to a page is always initialized
+** to zeros the first time a page is loaded into memory.
+**
+** The acquisition might fail for several reasons.  In all cases,
+** an appropriate error code is returned and *ppPage is set to NULL.
+**
+** See also sqlite3PagerLookup().  Both this routine and Lookup() attempt
+** to find a page in the in-memory cache first.  If the page is not already
+** in memory, this routine goes to disk to read it in whereas Lookup()
+** just returns 0.  This routine acquires a read-lock the first time it
+** has to go to disk, and could also playback an old journal if necessary.
+** Since Lookup() never goes to disk, it never has to deal with locks
+** or journal files.
+**
+** If noContent is false, the page contents are actually read from disk.
+** If noContent is true, it means that we do not care about the contents
+** of the page at this time, so do not do a disk read.  Just fill in the
+** page content with zeros.  But mark the fact that we have not read the
+** content by setting the PgHdr.needRead flag.  Later on, if 
+** sqlite3PagerWrite() is called on this page or if this routine is
+** called again with noContent==0, that means that the content is needed
+** and the disk read should occur at that point.
+*/
+static int pagerAcquire(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int noContent       /* Do not bother reading content from disk if true */
+){
+  PgHdr *pPg;
+  int rc;
+
+  assert( pPager->state==PAGER_UNLOCK || pPager->nRef>0 || pgno==1 );
+
+  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
+  ** number greater than this, or zero, is requested.
+  */
+  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+
+  /* Make sure we have not hit any critical errors.
+  */ 
+  assert( pPager!=0 );
+  *ppPage = 0;
+
+  /* If this is the first page accessed, then get a SHARED lock
+  ** on the database file. pagerSharedLock() is a no-op if 
+  ** a database lock is already held.
+  */
+  rc = pagerSharedLock(pPager);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( pPager->state!=PAGER_UNLOCK );
+
+  pPg = pager_lookup(pPager, pgno);
+  if( pPg==0 ){
+    /* The requested page is not in the page cache. */
+    int nMax;
+    int h;
+    PAGER_INCR(pPager->nMiss);
+    rc = pagerAllocatePage(pPager, &pPg);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    pPg->pgno = pgno;
+    assert( !MEMDB || pgno>pPager->stmtSize );
+    pPg->inJournal = sqlite3BitvecTest(pPager->pInJournal, pgno);
+    pPg->needSync = 0;
+
+    makeClean(pPg);
+    pPg->nRef = 1;
+
+    pPager->nRef++;
+    if( pPager->nExtra>0 ){
+      memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra);
+    }
+    nMax = sqlite3PagerPagecount(pPager);
+    if( pPager->errCode ){
+      rc = pPager->errCode;
+      sqlite3PagerUnref(pPg);
+      return rc;
+    }
+
+    /* Populate the page with data, either by reading from the database
+    ** file, or by setting the entire page to zero.
+    */
+    if( nMax<(int)pgno || MEMDB || (noContent && !pPager->alwaysRollback) ){
+      if( pgno>pPager->mxPgno ){
+        sqlite3PagerUnref(pPg);
+        return SQLITE_FULL;
+      }
+      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
+      pPg->needRead = noContent && !pPager->alwaysRollback;
+      IOTRACE(("ZERO %p %d\n", pPager, pgno));
+    }else{
+      rc = readDbPage(pPager, pPg, pgno);
+      if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
+        pPg->pgno = 0;
+        sqlite3PagerUnref(pPg);
+        return rc;
+      }
+      pPg->needRead = 0;
+    }
+
+    /* Link the page into the page hash table */
+    h = pgno & (pPager->nHash-1);
+    assert( pgno!=0 );
+    pPg->pNextHash = pPager->aHash[h];
+    pPager->aHash[h] = pPg;
+    if( pPg->pNextHash ){
+      assert( pPg->pNextHash->pPrevHash==0 );
+      pPg->pNextHash->pPrevHash = pPg;
+    }
+
+#ifdef SQLITE_CHECK_PAGES
+    pPg->pageHash = pager_pagehash(pPg);
+#endif
+  }else{
+    /* The requested page is in the page cache. */
+    assert(pPager->nRef>0 || pgno==1);
+    PAGER_INCR(pPager->nHit);
+    if( !noContent ){
+      rc = pager_get_content(pPg);
+      if( rc ){
+        return rc;
+      }
+    }
+    page_ref(pPg);
+  }
+  *ppPage = pPg;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3PagerAcquire(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int noContent       /* Do not bother reading content from disk if true */
+){
+  int rc;
+  pagerEnter(pPager);
+  rc = pagerAcquire(pPager, pgno, ppPage, noContent);
+  pagerLeave(pPager);
+  return rc;
+}
+
+
+/*
+** Acquire a page if it is already in the in-memory cache.  Do
+** not read the page from disk.  Return a pointer to the page,
+** or 0 if the page is not in cache.
+**
+** See also sqlite3PagerGet().  The difference between this routine
+** and sqlite3PagerGet() is that _get() will go to the disk and read
+** in the page if the page is not already in cache.  This routine
+** returns NULL if the page is not in cache or if a disk I/O error 
+** has ever happened.
+*/
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
+  PgHdr *pPg = 0;
+
+  assert( pPager!=0 );
+  assert( pgno!=0 );
+
+  pagerEnter(pPager);
+  if( pPager->state==PAGER_UNLOCK ){
+    assert( !pPager->pAll || pPager->exclusiveMode );
+  }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
+    /* Do nothing */
+  }else if( (pPg = pager_lookup(pPager, pgno))!=0 ){
+    page_ref(pPg);
+  }
+  pagerLeave(pPager);
+  return pPg;
+}
+
+/*
+** Release a page.
+**
+** If the number of references to the page drop to zero, then the
+** page is added to the LRU list.  When all references to all pages
+** are released, a rollback occurs and the lock on the database is
+** removed.
+*/
+SQLITE_PRIVATE int sqlite3PagerUnref(DbPage *pPg){
+  Pager *pPager;
+
+  if( pPg==0 ) return SQLITE_OK;
+  pPager = pPg->pPager;
+
+  /* Decrement the reference count for this page
+  */
+  assert( pPg->nRef>0 );
+  pagerEnter(pPg->pPager);
+  pPg->nRef--;
+
+  CHECK_PAGE(pPg);
+
+  /* When the number of references to a page reach 0, call the
+  ** destructor and add the page to the freelist.
+  */
+  if( pPg->nRef==0 ){
+
+    lruListAdd(pPg);
+    if( pPager->xDestructor ){
+      pPager->xDestructor(pPg, pPager->pageSize);
+    }
+  
+    /* When all pages reach the freelist, drop the read lock from
+    ** the database file.
+    */
+    pPager->nRef--;
+    assert( pPager->nRef>=0 );
+    if( pPager->nRef==0 && (!pPager->exclusiveMode || pPager->journalOff>0) ){
+      pagerUnlockAndRollback(pPager);
+    }
+  }
+  pagerLeave(pPager);
+  return SQLITE_OK;
+}
+
+/*
+** Create a journal file for pPager.  There should already be a RESERVED
+** or EXCLUSIVE lock on the database file when this routine is called.
+**
+** Return SQLITE_OK if everything.  Return an error code and release the
+** write lock if anything goes wrong.
+*/
+static int pager_open_journal(Pager *pPager){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  int flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_CREATE);
+
+  int rc;
+  assert( !MEMDB );
+  assert( pPager->state>=PAGER_RESERVED );
+  assert( pPager->useJournal );
+  assert( pPager->pInJournal==0 );
+  sqlite3PagerPagecount(pPager);
+  pagerLeave(pPager);
+  pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
+  pagerEnter(pPager);
+  if( pPager->pInJournal==0 ){
+    rc = SQLITE_NOMEM;
+    goto failed_to_open_journal;
+  }
+
+  if( pPager->journalOpen==0 ){
+    if( pPager->tempFile ){
+      flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
+    }else{
+      flags |= (SQLITE_OPEN_MAIN_JOURNAL);
+    }
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+    rc = sqlite3JournalOpen(
+        pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
+    );
+#else
+    rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
+#endif
+    assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
+    pPager->journalOff = 0;
+    pPager->setMaster = 0;
+    pPager->journalHdr = 0;
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_NOMEM ){
+        sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+      }
+      goto failed_to_open_journal;
+    }
+  }
+  pPager->journalOpen = 1;
+  pPager->journalStarted = 0;
+  pPager->needSync = 0;
+  pPager->alwaysRollback = 0;
+  pPager->nRec = 0;
+  if( pPager->errCode ){
+    rc = pPager->errCode;
+    goto failed_to_open_journal;
+  }
+  pPager->origDbSize = pPager->dbSize;
+
+  rc = writeJournalHdr(pPager);
+
+  if( pPager->stmtAutoopen && rc==SQLITE_OK ){
+    rc = sqlite3PagerStmtBegin(pPager);
+  }
+  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_NOMEM ){
+    rc = pager_end_transaction(pPager, 0);
+    if( rc==SQLITE_OK ){
+      rc = SQLITE_FULL;
+    }
+  }
+  return rc;
+
+failed_to_open_journal:
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  return rc;
+}
+
+/*
+** Acquire a write-lock on the database.  The lock is removed when
+** the any of the following happen:
+**
+**   *  sqlite3PagerCommitPhaseTwo() is called.
+**   *  sqlite3PagerRollback() is called.
+**   *  sqlite3PagerClose() is called.
+**   *  sqlite3PagerUnref() is called to on every outstanding page.
+**
+** The first parameter to this routine is a pointer to any open page of the
+** database file.  Nothing changes about the page - it is used merely to
+** acquire a pointer to the Pager structure and as proof that there is
+** already a read-lock on the database.
+**
+** The second parameter indicates how much space in bytes to reserve for a
+** master journal file-name at the start of the journal when it is created.
+**
+** A journal file is opened if this is not a temporary file.  For temporary
+** files, the opening of the journal file is deferred until there is an
+** actual need to write to the journal.
+**
+** If the database is already reserved for writing, this routine is a no-op.
+**
+** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
+** immediately instead of waiting until we try to flush the cache.  The
+** exFlag is ignored if a transaction is already active.
+*/
+SQLITE_PRIVATE int sqlite3PagerBegin(DbPage *pPg, int exFlag){
+  Pager *pPager = pPg->pPager;
+  int rc = SQLITE_OK;
+  pagerEnter(pPager);
+  assert( pPg->nRef>0 );
+  assert( pPager->state!=PAGER_UNLOCK );
+  if( pPager->state==PAGER_SHARED ){
+    assert( pPager->pInJournal==0 );
+    if( MEMDB ){
+      pPager->state = PAGER_EXCLUSIVE;
+      pPager->origDbSize = pPager->dbSize;
+    }else{
+      rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
+      if( rc==SQLITE_OK ){
+        pPager->state = PAGER_RESERVED;
+        if( exFlag ){
+          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        pagerLeave(pPager);
+        return rc;
+      }
+      pPager->dirtyCache = 0;
+      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
+      if( pPager->useJournal && !pPager->tempFile
+             && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+        rc = pager_open_journal(pPager);
+      }
+    }
+  }else if( pPager->journalOpen && pPager->journalOff==0 ){
+    /* This happens when the pager was in exclusive-access mode the last
+    ** time a (read or write) transaction was successfully concluded
+    ** by this connection. Instead of deleting the journal file it was 
+    ** kept open and either was truncated to 0 bytes or its header was
+    ** overwritten with zeros.
+    */
+    assert( pPager->nRec==0 );
+    assert( pPager->origDbSize==0 );
+    assert( pPager->pInJournal==0 );
+    sqlite3PagerPagecount(pPager);
+    pagerLeave(pPager);
+    pPager->pInJournal = sqlite3BitvecCreate( pPager->dbSize );
+    pagerEnter(pPager);
+    if( !pPager->pInJournal ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pPager->origDbSize = pPager->dbSize;
+      rc = writeJournalHdr(pPager);
+    }
+  }
+  assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Make a page dirty.  Set its dirty flag and add it to the dirty
+** page list.
+*/
+static void makeDirty(PgHdr *pPg){
+  if( pPg->dirty==0 ){
+    Pager *pPager = pPg->pPager;
+    pPg->dirty = 1;
+    pPg->pDirty = pPager->pDirty;
+    if( pPager->pDirty ){
+      pPager->pDirty->pPrevDirty = pPg;
+    }
+    pPg->pPrevDirty = 0;
+    pPager->pDirty = pPg;
+  }
+}
+
+/*
+** Make a page clean.  Clear its dirty bit and remove it from the
+** dirty page list.
+*/
+static void makeClean(PgHdr *pPg){
+  if( pPg->dirty ){
+    pPg->dirty = 0;
+    if( pPg->pDirty ){
+      assert( pPg->pDirty->pPrevDirty==pPg );
+      pPg->pDirty->pPrevDirty = pPg->pPrevDirty;
+    }
+    if( pPg->pPrevDirty ){
+      assert( pPg->pPrevDirty->pDirty==pPg );
+      pPg->pPrevDirty->pDirty = pPg->pDirty;
+    }else{
+      assert( pPg->pPager->pDirty==pPg );
+      pPg->pPager->pDirty = pPg->pDirty;
+    }
+  }
+}
+
+
+/*
+** Mark a data page as writeable.  The page is written into the journal 
+** if it is not there already.  This routine must be called before making
+** changes to a page.
+**
+** The first time this routine is called, the pager creates a new
+** journal and acquires a RESERVED lock on the database.  If the RESERVED
+** lock could not be acquired, this routine returns SQLITE_BUSY.  The
+** calling routine must check for that return value and be careful not to
+** change any page data until this routine returns SQLITE_OK.
+**
+** If the journal file could not be written because the disk is full,
+** then this routine returns SQLITE_FULL and does an immediate rollback.
+** All subsequent write attempts also return SQLITE_FULL until there
+** is a call to sqlite3PagerCommit() or sqlite3PagerRollback() to
+** reset.
+*/
+static int pager_write(PgHdr *pPg){
+  void *pData = PGHDR_TO_DATA(pPg);
+  Pager *pPager = pPg->pPager;
+  int rc = SQLITE_OK;
+
+  /* Check for errors
+  */
+  if( pPager->errCode ){ 
+    return pPager->errCode;
+  }
+  if( pPager->readOnly ){
+    return SQLITE_PERM;
+  }
+
+  assert( !pPager->setMaster );
+
+  CHECK_PAGE(pPg);
+
+  /* If this page was previously acquired with noContent==1, that means
+  ** we didn't really read in the content of the page.  This can happen
+  ** (for example) when the page is being moved to the freelist.  But
+  ** now we are (perhaps) moving the page off of the freelist for
+  ** reuse and we need to know its original content so that content
+  ** can be stored in the rollback journal.  So do the read at this
+  ** time.
+  */
+  rc = pager_get_content(pPg);
+  if( rc ){
+    return rc;
+  }
+
+  /* Mark the page as dirty.  If the page has already been written
+  ** to the journal then we can return right away.
+  */
+  makeDirty(pPg);
+  if( pPg->inJournal && (pageInStatement(pPg) || pPager->stmtInUse==0) ){
+    pPager->dirtyCache = 1;
+    pPager->dbModified = 1;
+  }else{
+
+    /* If we get this far, it means that the page needs to be
+    ** written to the transaction journal or the ckeckpoint journal
+    ** or both.
+    **
+    ** First check to see that the transaction journal exists and
+    ** create it if it does not.
+    */
+    assert( pPager->state!=PAGER_UNLOCK );
+    rc = sqlite3PagerBegin(pPg, 0);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    assert( pPager->state>=PAGER_RESERVED );
+    if( !pPager->journalOpen && pPager->useJournal
+          && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+      rc = pager_open_journal(pPager);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    pPager->dirtyCache = 1;
+    pPager->dbModified = 1;
+  
+    /* The transaction journal now exists and we have a RESERVED or an
+    ** EXCLUSIVE lock on the main database file.  Write the current page to
+    ** the transaction journal if it is not there already.
+    */
+    if( !pPg->inJournal && (pPager->journalOpen || MEMDB) ){
+      if( (int)pPg->pgno <= pPager->origDbSize ){
+        if( MEMDB ){
+          PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+          PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
+          assert( pHist->pOrig==0 );
+          pHist->pOrig = sqlite3_malloc( pPager->pageSize );
+          if( !pHist->pOrig ){
+            return SQLITE_NOMEM;
+          }
+          memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
+        }else{
+          u32 cksum;
+          char *pData2;
+
+          /* We should never write to the journal file the page that
+          ** contains the database locks.  The following assert verifies
+          ** that we do not. */
+          assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
+          pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
+          cksum = pager_cksum(pPager, (u8*)pData2);
+          rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
+                                pPager->journalOff + 4);
+            pPager->journalOff += pPager->pageSize+4;
+          }
+          if( rc==SQLITE_OK ){
+            rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
+            pPager->journalOff += 4;
+          }
+          IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno, 
+                   pPager->journalOff, pPager->pageSize));
+          PAGER_INCR(sqlite3_pager_writej_count);
+          PAGERTRACE5("JOURNAL %d page %d needSync=%d hash(%08x)\n",
+               PAGERID(pPager), pPg->pgno, pPg->needSync, pager_pagehash(pPg));
+
+          /* An error has occured writing to the journal file. The 
+          ** transaction will be rolled back by the layer above.
+          */
+          if( rc!=SQLITE_OK ){
+            return rc;
+          }
+
+          pPager->nRec++;
+          assert( pPager->pInJournal!=0 );
+          sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
+          pPg->needSync = !pPager->noSync;
+          if( pPager->stmtInUse ){
+            sqlite3BitvecSet(pPager->pInStmt, pPg->pgno);
+          }
+        }
+      }else{
+        pPg->needSync = !pPager->journalStarted && !pPager->noSync;
+        PAGERTRACE4("APPEND %d page %d needSync=%d\n",
+                PAGERID(pPager), pPg->pgno, pPg->needSync);
+      }
+      if( pPg->needSync ){
+        pPager->needSync = 1;
+      }
+      pPg->inJournal = 1;
+    }
+  
+    /* If the statement journal is open and the page is not in it,
+    ** then write the current page to the statement journal.  Note that
+    ** the statement journal format differs from the standard journal format
+    ** in that it omits the checksums and the header.
+    */
+    if( pPager->stmtInUse 
+     && !pageInStatement(pPg) 
+     && (int)pPg->pgno<=pPager->stmtSize 
+    ){
+      assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
+      if( MEMDB ){
+        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+        assert( pHist->pStmt==0 );
+        pHist->pStmt = sqlite3_malloc( pPager->pageSize );
+        if( pHist->pStmt ){
+          memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
+        }
+        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
+        page_add_to_stmt_list(pPg);
+      }else{
+        i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
+        char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
+        rc = write32bits(pPager->stfd, offset, pPg->pgno);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize, offset+4);
+        }
+        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        pPager->stmtNRec++;
+        assert( pPager->pInStmt!=0 );
+        sqlite3BitvecSet(pPager->pInStmt, pPg->pgno);
+      }
+    }
+  }
+
+  /* Update the database size and return.
+  */
+  assert( pPager->state>=PAGER_SHARED );
+  if( pPager->dbSize<(int)pPg->pgno ){
+    pPager->dbSize = pPg->pgno;
+    if( !MEMDB && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){
+      pPager->dbSize++;
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used to mark a data-page as writable. It uses 
+** pager_write() to open a journal file (if it is not already open)
+** and write the page *pData to the journal.
+**
+** The difference between this function and pager_write() is that this
+** function also deals with the special case where 2 or more pages
+** fit on a single disk sector. In this case all co-resident pages
+** must have been written to the journal file before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
+  int rc = SQLITE_OK;
+
+  PgHdr *pPg = pDbPage;
+  Pager *pPager = pPg->pPager;
+  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
+
+  pagerEnter(pPager);
+  if( !MEMDB && nPagePerSector>1 ){
+    Pgno nPageCount;          /* Total number of pages in database file */
+    Pgno pg1;                 /* First page of the sector pPg is located on. */
+    int nPage;                /* Number of pages starting at pg1 to journal */
+    int ii;
+    int needSync = 0;
+
+    /* Set the doNotSync flag to 1. This is because we cannot allow a journal
+    ** header to be written between the pages journaled by this function.
+    */
+    assert( pPager->doNotSync==0 );
+    pPager->doNotSync = 1;
+
+    /* This trick assumes that both the page-size and sector-size are
+    ** an integer power of 2. It sets variable pg1 to the identifier
+    ** of the first page of the sector pPg is located on.
+    */
+    pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
+
+    nPageCount = sqlite3PagerPagecount(pPager);
+    if( pPg->pgno>nPageCount ){
+      nPage = (pPg->pgno - pg1)+1;
+    }else if( (pg1+nPagePerSector-1)>nPageCount ){
+      nPage = nPageCount+1-pg1;
+    }else{
+      nPage = nPagePerSector;
+    }
+    assert(nPage>0);
+    assert(pg1<=pPg->pgno);
+    assert((pg1+nPage)>pPg->pgno);
+
+    for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
+      Pgno pg = pg1+ii;
+      PgHdr *pPage;
+      if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){
+        if( pg!=PAGER_MJ_PGNO(pPager) ){
+          rc = sqlite3PagerGet(pPager, pg, &pPage);
+          if( rc==SQLITE_OK ){
+            rc = pager_write(pPage);
+            if( pPage->needSync ){
+              needSync = 1;
+            }
+            sqlite3PagerUnref(pPage);
+          }
+        }
+      }else if( (pPage = pager_lookup(pPager, pg))!=0 ){
+        if( pPage->needSync ){
+          needSync = 1;
+        }
+      }
+    }
+
+    /* If the PgHdr.needSync flag is set for any of the nPage pages 
+    ** starting at pg1, then it needs to be set for all of them. Because
+    ** writing to any of these nPage pages may damage the others, the
+    ** journal file must contain sync()ed copies of all of them
+    ** before any of them can be written out to the database file.
+    */
+    if( needSync ){
+      for(ii=0; ii<nPage && needSync; ii++){
+        PgHdr *pPage = pager_lookup(pPager, pg1+ii);
+        if( pPage ) pPage->needSync = 1;
+      }
+      assert(pPager->needSync);
+    }
+
+    assert( pPager->doNotSync==1 );
+    pPager->doNotSync = 0;
+  }else{
+    rc = pager_write(pDbPage);
+  }
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Return TRUE if the page given in the argument was previously passed
+** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
+** to change the content of the page.
+*/
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
+  return pPg->dirty;
+}
+#endif
+
+/*
+** A call to this routine tells the pager that it is not necessary to
+** write the information on page pPg back to the disk, even though
+** that page might be marked as dirty.
+**
+** The overlying software layer calls this routine when all of the data
+** on the given page is unused.  The pager marks the page as clean so
+** that it does not get written to disk.
+**
+** Tests show that this optimization, together with the
+** sqlite3PagerDontRollback() below, more than double the speed
+** of large INSERT operations and quadruple the speed of large DELETEs.
+**
+** When this routine is called, set the alwaysRollback flag to true.
+** Subsequent calls to sqlite3PagerDontRollback() for the same page
+** will thereafter be ignored.  This is necessary to avoid a problem
+** where a page with data is added to the freelist during one part of
+** a transaction then removed from the freelist during a later part
+** of the same transaction and reused for some other purpose.  When it
+** is first added to the freelist, this routine is called.  When reused,
+** the sqlite3PagerDontRollback() routine is called.  But because the
+** page contains critical data, we still need to be sure it gets
+** rolled back in spite of the sqlite3PagerDontRollback() call.
+*/
+SQLITE_PRIVATE void sqlite3PagerDontWrite(DbPage *pDbPage){
+  PgHdr *pPg = pDbPage;
+  Pager *pPager = pPg->pPager;
+
+  if( MEMDB ) return;
+  pagerEnter(pPager);
+  pPg->alwaysRollback = 1;
+  if( pPg->dirty && !pPager->stmtInUse ){
+    assert( pPager->state>=PAGER_SHARED );
+    if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
+      /* If this pages is the last page in the file and the file has grown
+      ** during the current transaction, then do NOT mark the page as clean.
+      ** When the database file grows, we must make sure that the last page
+      ** gets written at least once so that the disk file will be the correct
+      ** size. If you do not write this page and the size of the file
+      ** on the disk ends up being too small, that can lead to database
+      ** corruption during the next transaction.
+      */
+    }else{
+      PAGERTRACE3("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager));
+      IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
+      makeClean(pPg);
+#ifdef SQLITE_CHECK_PAGES
+      pPg->pageHash = pager_pagehash(pPg);
+#endif
+    }
+  }
+  pagerLeave(pPager);
+}
+
+/*
+** A call to this routine tells the pager that if a rollback occurs,
+** it is not necessary to restore the data on the given page.  This
+** means that the pager does not have to record the given page in the
+** rollback journal.
+**
+** If we have not yet actually read the content of this page (if
+** the PgHdr.needRead flag is set) then this routine acts as a promise
+** that we will never need to read the page content in the future.
+** so the needRead flag can be cleared at this point.
+*/
+SQLITE_PRIVATE void sqlite3PagerDontRollback(DbPage *pPg){
+  Pager *pPager = pPg->pPager;
+
+  pagerEnter(pPager);
+  assert( pPager->state>=PAGER_RESERVED );
+
+  /* If the journal file is not open, or DontWrite() has been called on
+  ** this page (DontWrite() sets the alwaysRollback flag), then this
+  ** function is a no-op.
+  */
+  if( pPager->journalOpen==0 || pPg->alwaysRollback || pPager->alwaysRollback ){
+    pagerLeave(pPager);
+    return;
+  }
+  assert( !MEMDB );    /* For a memdb, pPager->journalOpen is always 0 */
+
+#ifdef SQLITE_SECURE_DELETE
+  if( pPg->inJournal || (int)pPg->pgno > pPager->origDbSize ){
+    return;
+  }
+#endif
+
+  /* If SECURE_DELETE is disabled, then there is no way that this
+  ** routine can be called on a page for which sqlite3PagerDontWrite()
+  ** has not been previously called during the same transaction.
+  ** And if DontWrite() has previously been called, the following
+  ** conditions must be met.
+  */
+  assert( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize );
+
+  assert( pPager->pInJournal!=0 );
+  sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
+  pPg->inJournal = 1;
+  pPg->needRead = 0;
+  if( pPager->stmtInUse ){
+    assert( pPager->stmtSize >= pPager->origDbSize );
+    sqlite3BitvecSet(pPager->pInStmt, pPg->pgno);
+  }
+  PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
+  IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
+  pagerLeave(pPager);
+}
+
+
+/*
+** This routine is called to increment the database file change-counter,
+** stored at byte 24 of the pager file.
+*/
+static int pager_incr_changecounter(Pager *pPager, int isDirect){
+  PgHdr *pPgHdr;
+  u32 change_counter;
+  int rc = SQLITE_OK;
+
+  if( !pPager->changeCountDone ){
+    /* Open page 1 of the file for writing. */
+    rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
+    if( rc!=SQLITE_OK ) return rc;
+
+    if( !isDirect ){
+      rc = sqlite3PagerWrite(pPgHdr);
+      if( rc!=SQLITE_OK ){
+        sqlite3PagerUnref(pPgHdr);
+        return rc;
+      }
+    }
+
+    /* Increment the value just read and write it back to byte 24. */
+    change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
+    change_counter++;
+    put32bits(((char*)PGHDR_TO_DATA(pPgHdr))+24, change_counter);
+
+    if( isDirect && pPager->fd->pMethods ){
+      const void *zBuf = PGHDR_TO_DATA(pPgHdr);
+      rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
+    }
+
+    /* Release the page reference. */
+    sqlite3PagerUnref(pPgHdr);
+    pPager->changeCountDone = 1;
+  }
+  return rc;
+}
+
+/*
+** Sync the pager file to disk.
+*/
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager){
+  int rc;
+  pagerEnter(pPager);
+  rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Sync the database file for the pager pPager. zMaster points to the name
+** of a master journal file that should be written into the individual
+** journal file. zMaster may be NULL, which is interpreted as no master
+** journal (a single database transaction).
+**
+** This routine ensures that the journal is synced, all dirty pages written
+** to the database file and the database file synced. The only thing that
+** remains to commit the transaction is to delete the journal file (or
+** master journal file if specified).
+**
+** Note that if zMaster==NULL, this does not overwrite a previous value
+** passed to an sqlite3PagerCommitPhaseOne() call.
+**
+** If parameter nTrunc is non-zero, then the pager file is truncated to
+** nTrunc pages (this is used by auto-vacuum databases).
+**
+** If the final parameter - noSync - is true, then the database file itself
+** is not synced. The caller must call sqlite3PagerSync() directly to
+** sync the database file before calling CommitPhaseTwo() to delete the
+** journal file in this case.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
+  Pager *pPager, 
+  const char *zMaster, 
+  Pgno nTrunc,
+  int noSync
+){
+  int rc = SQLITE_OK;
+
+  /* If no changes have been made, we can leave the transaction early.
+  */
+  if( pPager->dbModified==0 &&
+        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
+          pPager->exclusiveMode!=0) ){
+    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
+    return SQLITE_OK;
+  }
+
+  PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
+      pPager->zFilename, zMaster, nTrunc);
+  pagerEnter(pPager);
+
+  /* If this is an in-memory db, or no pages have been written to, or this
+  ** function has already been called, it is a no-op.
+  */
+  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
+    PgHdr *pPg;
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+    /* The atomic-write optimization can be used if all of the
+    ** following are true:
+    **
+    **    + The file-system supports the atomic-write property for
+    **      blocks of size page-size, and
+    **    + This commit is not part of a multi-file transaction, and
+    **    + Exactly one page has been modified and store in the journal file.
+    **
+    ** If the optimization can be used, then the journal file will never
+    ** be created for this transaction.
+    */
+    int useAtomicWrite = (
+        !zMaster && 
+        pPager->journalOpen &&
+        pPager->journalOff==jrnlBufferSize(pPager) && 
+        nTrunc==0 && 
+        (0==pPager->pDirty || 0==pPager->pDirty->pDirty)
+    );
+    assert( pPager->journalOpen || pPager->journalMode==PAGER_JOURNALMODE_OFF );
+    if( useAtomicWrite ){
+      /* Update the nRec field in the journal file. */
+      int offset = pPager->journalHdr + sizeof(aJournalMagic);
+      assert(pPager->nRec==1);
+      rc = write32bits(pPager->jfd, offset, pPager->nRec);
+
+      /* Update the db file change counter. The following call will modify
+      ** the in-memory representation of page 1 to include the updated
+      ** change counter and then write page 1 directly to the database
+      ** file. Because of the atomic-write property of the host file-system, 
+      ** this is safe.
+      */
+      if( rc==SQLITE_OK ){
+        rc = pager_incr_changecounter(pPager, 1);
+      }
+    }else{
+      rc = sqlite3JournalCreate(pPager->jfd);
+    }
+
+    if( !useAtomicWrite && rc==SQLITE_OK )
+#endif
+
+    /* If a master journal file name has already been written to the
+    ** journal file, then no sync is required. This happens when it is
+    ** written, then the process fails to upgrade from a RESERVED to an
+    ** EXCLUSIVE lock. The next time the process tries to commit the
+    ** transaction the m-j name will have already been written.
+    */
+    if( !pPager->setMaster ){
+      rc = pager_incr_changecounter(pPager, 0);
+      if( rc!=SQLITE_OK ) goto sync_exit;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( nTrunc!=0 ){
+        /* If this transaction has made the database smaller, then all pages
+        ** being discarded by the truncation must be written to the journal
+        ** file.
+        */
+        Pgno i;
+        int iSkip = PAGER_MJ_PGNO(pPager);
+        for( i=nTrunc+1; i<=pPager->origDbSize; i++ ){
+          if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){
+            rc = sqlite3PagerGet(pPager, i, &pPg);
+            if( rc!=SQLITE_OK ) goto sync_exit;
+            rc = sqlite3PagerWrite(pPg);
+            sqlite3PagerUnref(pPg);
+            if( rc!=SQLITE_OK ) goto sync_exit;
+          }
+        } 
+      }
+#endif
+      rc = writeMasterJournal(pPager, zMaster);
+      if( rc!=SQLITE_OK ) goto sync_exit;
+      rc = syncJournal(pPager);
+    }
+    if( rc!=SQLITE_OK ) goto sync_exit;
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( nTrunc!=0 ){
+      rc = sqlite3PagerTruncate(pPager, nTrunc);
+      if( rc!=SQLITE_OK ) goto sync_exit;
+    }
+#endif
+
+    /* Write all dirty pages to the database file */
+    pPg = pager_get_all_dirty_pages(pPager);
+    rc = pager_write_pagelist(pPg);
+    if( rc!=SQLITE_OK ){
+      assert( rc!=SQLITE_IOERR_BLOCKED );
+      /* The error might have left the dirty list all fouled up here,
+      ** but that does not matter because if the if the dirty list did
+      ** get corrupted, then the transaction will roll back and
+      ** discard the dirty list.  There is an assert in
+      ** pager_get_all_dirty_pages() that verifies that no attempt
+      ** is made to use an invalid dirty list.
+      */
+      goto sync_exit;
+    }
+    pPager->pDirty = 0;
+
+    /* Sync the database file. */
+    if( !pPager->noSync && !noSync ){
+      rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
+    }
+    IOTRACE(("DBSYNC %p\n", pPager))
+
+    pPager->state = PAGER_SYNCED;
+  }else if( MEMDB && nTrunc!=0 ){
+    rc = sqlite3PagerTruncate(pPager, nTrunc);
+  }
+
+sync_exit:
+  if( rc==SQLITE_IOERR_BLOCKED ){
+    /* pager_incr_changecounter() may attempt to obtain an exclusive
+     * lock to spill the cache and return IOERR_BLOCKED. But since 
+     * there is no chance the cache is inconsistent, it is
+     * better to return SQLITE_BUSY.
+     */
+    rc = SQLITE_BUSY;
+  }
+  pagerLeave(pPager);
+  return rc;
+}
+
+
+/*
+** Commit all changes to the database and release the write lock.
+**
+** If the commit fails for any reason, a rollback attempt is made
+** and an error code is returned.  If the commit worked, SQLITE_OK
+** is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
+  int rc;
+  PgHdr *pPg;
+
+  if( pPager->errCode ){
+    return pPager->errCode;
+  }
+  if( pPager->state<PAGER_RESERVED ){
+    return SQLITE_ERROR;
+  }
+  if( pPager->dbModified==0 &&
+        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
+          pPager->exclusiveMode!=0) ){
+    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
+    return SQLITE_OK;
+  }
+  pagerEnter(pPager);
+  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
+  if( MEMDB ){
+    pPg = pager_get_all_dirty_pages(pPager);
+    while( pPg ){
+      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+      clearHistory(pHist);
+      pPg->dirty = 0;
+      pPg->inJournal = 0;
+      pHist->inStmt = 0;
+      pPg->needSync = 0;
+      pHist->pPrevStmt = pHist->pNextStmt = 0;
+      pPg = pPg->pDirty;
+    }
+    pPager->pDirty = 0;
+#ifndef NDEBUG
+    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+      assert( !pPg->alwaysRollback );
+      assert( !pHist->pOrig );
+      assert( !pHist->pStmt );
+    }
+#endif
+    pPager->pStmt = 0;
+    pPager->state = PAGER_SHARED;
+    pagerLeave(pPager);
+    return SQLITE_OK;
+  }
+  assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
+  rc = pager_end_transaction(pPager, pPager->setMaster);
+  rc = pager_error(pPager, rc);
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Rollback all changes.  The database falls back to PAGER_SHARED mode.
+** All in-memory cache pages revert to their original data contents.
+** The journal is deleted.
+**
+** This routine cannot fail unless some other process is not following
+** the correct locking protocol or unless some other
+** process is writing trash into the journal file (SQLITE_CORRUPT) or
+** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
+** codes are returned for all these occasions.  Otherwise,
+** SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager *pPager){
+  int rc;
+  PAGERTRACE2("ROLLBACK %d\n", PAGERID(pPager));
+  if( MEMDB ){
+    PgHdr *p;
+    for(p=pPager->pAll; p; p=p->pNextAll){
+      PgHistory *pHist;
+      assert( !p->alwaysRollback );
+      if( !p->dirty ){
+        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
+        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
+        continue;
+      }
+
+      pHist = PGHDR_TO_HIST(p, pPager);
+      if( pHist->pOrig ){
+        memcpy(PGHDR_TO_DATA(p), pHist->pOrig, pPager->pageSize);
+        PAGERTRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, PAGERID(pPager));
+      }else{
+        PAGERTRACE3("PAGE %d is clean on %d\n", p->pgno, PAGERID(pPager));
+      }
+      clearHistory(pHist);
+      p->dirty = 0;
+      p->inJournal = 0;
+      pHist->inStmt = 0;
+      pHist->pPrevStmt = pHist->pNextStmt = 0;
+      if( pPager->xReiniter ){
+        pPager->xReiniter(p, pPager->pageSize);
+      }
+    }
+    pPager->pDirty = 0;
+    pPager->pStmt = 0;
+    pPager->dbSize = pPager->origDbSize;
+    pager_truncate_cache(pPager);
+    pPager->stmtInUse = 0;
+    pPager->state = PAGER_SHARED;
+    return SQLITE_OK;
+  }
+
+  pagerEnter(pPager);
+  if( !pPager->dirtyCache || !pPager->journalOpen ){
+    rc = pager_end_transaction(pPager, pPager->setMaster);
+    pagerLeave(pPager);
+    return rc;
+  }
+
+  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
+    if( pPager->state>=PAGER_EXCLUSIVE ){
+      pager_playback(pPager, 0);
+    }
+    pagerLeave(pPager);
+    return pPager->errCode;
+  }
+  if( pPager->state==PAGER_RESERVED ){
+    int rc2;
+    rc = pager_playback(pPager, 0);
+    rc2 = pager_end_transaction(pPager, pPager->setMaster);
+    if( rc==SQLITE_OK ){
+      rc = rc2;
+    }
+  }else{
+    rc = pager_playback(pPager, 0);
+  }
+  /* pager_reset(pPager); */
+  pPager->dbSize = -1;
+
+  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
+  ** cache. So call pager_error() on the way out to make any error 
+  ** persistent.
+  */
+  rc = pager_error(pPager, rc);
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Return TRUE if the database file is opened read-only.  Return FALSE
+** if the database is (in theory) writable.
+*/
+SQLITE_PRIVATE int sqlite3PagerIsreadonly(Pager *pPager){
+  return pPager->readOnly;
+}
+
+/*
+** Return the number of references to the pager.
+*/
+SQLITE_PRIVATE int sqlite3PagerRefcount(Pager *pPager){
+  return pPager->nRef;
+}
+
+#ifdef SQLITE_TEST
+/*
+** This routine is used for testing and analysis only.
+*/
+SQLITE_PRIVATE int *sqlite3PagerStats(Pager *pPager){
+  static int a[11];
+  a[0] = pPager->nRef;
+  a[1] = pPager->nPage;
+  a[2] = pPager->mxPage;
+  a[3] = pPager->dbSize;
+  a[4] = pPager->state;
+  a[5] = pPager->errCode;
+  a[6] = pPager->nHit;
+  a[7] = pPager->nMiss;
+  a[8] = 0;  /* Used to be pPager->nOvfl */
+  a[9] = pPager->nRead;
+  a[10] = pPager->nWrite;
+  return a;
+}
+#endif
+
+/*
+** Set the statement rollback point.
+**
+** This routine should be called with the transaction journal already
+** open.  A new statement journal is created that can be used to rollback
+** changes of a single SQL command within a larger transaction.
+*/
+static int pagerStmtBegin(Pager *pPager){
+  int rc;
+  assert( !pPager->stmtInUse );
+  assert( pPager->state>=PAGER_SHARED );
+  assert( pPager->dbSize>=0 );
+  PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
+  if( MEMDB ){
+    pPager->stmtInUse = 1;
+    pPager->stmtSize = pPager->dbSize;
+    return SQLITE_OK;
+  }
+  if( !pPager->journalOpen ){
+    pPager->stmtAutoopen = 1;
+    return SQLITE_OK;
+  }
+  assert( pPager->journalOpen );
+  pagerLeave(pPager);
+  assert( pPager->pInStmt==0 );
+  pPager->pInStmt = sqlite3BitvecCreate(pPager->dbSize);
+  pagerEnter(pPager);
+  if( pPager->pInStmt==0 ){
+    /* sqlite3OsLock(pPager->fd, SHARED_LOCK); */
+    return SQLITE_NOMEM;
+  }
+  pPager->stmtJSize = pPager->journalOff;
+  pPager->stmtSize = pPager->dbSize;
+  pPager->stmtHdrOff = 0;
+  pPager->stmtCksum = pPager->cksumInit;
+  if( !pPager->stmtOpen ){
+    rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->stfd, pPager->zStmtJrnl,
+                              SQLITE_OPEN_SUBJOURNAL);
+    if( rc ){
+      goto stmt_begin_failed;
+    }
+    pPager->stmtOpen = 1;
+    pPager->stmtNRec = 0;
+  }
+  pPager->stmtInUse = 1;
+  return SQLITE_OK;
+ 
+stmt_begin_failed:
+  if( pPager->pInStmt ){
+    sqlite3BitvecDestroy(pPager->pInStmt);
+    pPager->pInStmt = 0;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3PagerStmtBegin(Pager *pPager){
+  int rc;
+  pagerEnter(pPager);
+  rc = pagerStmtBegin(pPager);
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Commit a statement.
+*/
+SQLITE_PRIVATE int sqlite3PagerStmtCommit(Pager *pPager){
+  pagerEnter(pPager);
+  if( pPager->stmtInUse ){
+    PgHdr *pPg, *pNext;
+    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
+    if( !MEMDB ){
+      /* sqlite3OsTruncate(pPager->stfd, 0); */
+      sqlite3BitvecDestroy(pPager->pInStmt);
+      pPager->pInStmt = 0;
+    }else{
+      for(pPg=pPager->pStmt; pPg; pPg=pNext){
+        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
+        pNext = pHist->pNextStmt;
+        assert( pHist->inStmt );
+        pHist->inStmt = 0;
+        pHist->pPrevStmt = pHist->pNextStmt = 0;
+        sqlite3_free(pHist->pStmt);
+        pHist->pStmt = 0;
+      }
+    }
+    pPager->stmtNRec = 0;
+    pPager->stmtInUse = 0;
+    pPager->pStmt = 0;
+  }
+  pPager->stmtAutoopen = 0;
+  pagerLeave(pPager);
+  return SQLITE_OK;
+}
+
+/*
+** Rollback a statement.
+*/
+SQLITE_PRIVATE int sqlite3PagerStmtRollback(Pager *pPager){
+  int rc;
+  pagerEnter(pPager);
+  if( pPager->stmtInUse ){
+    PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
+    if( MEMDB ){
+      PgHdr *pPg;
+      PgHistory *pHist;
+      for(pPg=pPager->pStmt; pPg; pPg=pHist->pNextStmt){
+        pHist = PGHDR_TO_HIST(pPg, pPager);
+        if( pHist->pStmt ){
+          memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize);
+          sqlite3_free(pHist->pStmt);
+          pHist->pStmt = 0;
+        }
+      }
+      pPager->dbSize = pPager->stmtSize;
+      pager_truncate_cache(pPager);
+      rc = SQLITE_OK;
+    }else{
+      rc = pager_stmt_playback(pPager);
+    }
+    sqlite3PagerStmtCommit(pPager);
+  }else{
+    rc = SQLITE_OK;
+  }
+  pPager->stmtAutoopen = 0;
+  pagerLeave(pPager);
+  return rc;
+}
+
+/*
+** Return the full pathname of the database file.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager *pPager){
+  return pPager->zFilename;
+}
+
+/*
+** Return the VFS structure for the pager.
+*/
+SQLITE_PRIVATE const sqlite3_vfs *sqlite3PagerVfs(Pager *pPager){
+  return pPager->pVfs;
+}
+
+/*
+** Return the file handle for the database file associated
+** with the pager.  This might return NULL if the file has
+** not yet been opened.
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager *pPager){
+  return pPager->fd;
+}
+
+/*
+** Return the directory of the database file.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerDirname(Pager *pPager){
+  return pPager->zDirectory;
+}
+
+/*
+** Return the full pathname of the journal file.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager *pPager){
+  return pPager->zJournal;
+}
+
+/*
+** Return true if fsync() calls are disabled for this pager.  Return FALSE
+** if fsync()s are executed normally.
+*/
+SQLITE_PRIVATE int sqlite3PagerNosync(Pager *pPager){
+  return pPager->noSync;
+}
+
+#ifdef SQLITE_HAS_CODEC
+/*
+** Set the codec for this pager
+*/
+SQLITE_PRIVATE void sqlite3PagerSetCodec(
+  Pager *pPager,
+  void *(*xCodec)(void*,void*,Pgno,int),
+  void *pCodecArg
+){
+  pPager->xCodec = xCodec;
+  pPager->pCodecArg = pCodecArg;
+}
+#endif
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Move the page pPg to location pgno in the file.
+**
+** There must be no references to the page previously located at
+** pgno (which we call pPgOld) though that page is allowed to be
+** in cache.  If the page previous located at pgno is not already
+** in the rollback journal, it is not put there by by this routine.
+**
+** References to the page pPg remain valid. Updating any
+** meta-data associated with pPg (i.e. data stored in the nExtra bytes
+** allocated along with the page) is the responsibility of the caller.
+**
+** A transaction must be active when this routine is called. It used to be
+** required that a statement transaction was not active, but this restriction
+** has been removed (CREATE INDEX needs to move a page when a statement
+** transaction is active).
+*/
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
+  PgHdr *pPgOld;  /* The page being overwritten. */
+  int h;
+  Pgno needSyncPgno = 0;
+
+  pagerEnter(pPager);
+  assert( pPg->nRef>0 );
+
+  PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n", 
+      PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
+  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
+
+  pager_get_content(pPg);
+  if( pPg->needSync ){
+    needSyncPgno = pPg->pgno;
+    assert( pPg->inJournal || (int)pgno>pPager->origDbSize );
+    assert( pPg->dirty );
+    assert( pPager->needSync );
+  }
+
+  /* Unlink pPg from its hash-chain */
+  unlinkHashChain(pPager, pPg);
+
+  /* If the cache contains a page with page-number pgno, remove it
+  ** from its hash chain. Also, if the PgHdr.needSync was set for 
+  ** page pgno before the 'move' operation, it needs to be retained 
+  ** for the page moved there.
+  */
+  pPg->needSync = 0;
+  pPgOld = pager_lookup(pPager, pgno);
+  if( pPgOld ){
+    assert( pPgOld->nRef==0 );
+    unlinkHashChain(pPager, pPgOld);
+    makeClean(pPgOld);
+    pPg->needSync = pPgOld->needSync;
+  }else{
+    pPg->needSync = 0;
+  }
+  pPg->inJournal = sqlite3BitvecTest(pPager->pInJournal, pgno);
+
+  /* Change the page number for pPg and insert it into the new hash-chain. */
+  assert( pgno!=0 );
+  pPg->pgno = pgno;
+  h = pgno & (pPager->nHash-1);
+  if( pPager->aHash[h] ){
+    assert( pPager->aHash[h]->pPrevHash==0 );
+    pPager->aHash[h]->pPrevHash = pPg;
+  }
+  pPg->pNextHash = pPager->aHash[h];
+  pPager->aHash[h] = pPg;
+  pPg->pPrevHash = 0;
+
+  makeDirty(pPg);
+  pPager->dirtyCache = 1;
+  pPager->dbModified = 1;
+
+  if( needSyncPgno ){
+    /* If needSyncPgno is non-zero, then the journal file needs to be 
+    ** sync()ed before any data is written to database file page needSyncPgno.
+    ** Currently, no such page exists in the page-cache and the 
+    ** Pager.pInJournal bit has been set. This needs to be remedied by loading
+    ** the page into the pager-cache and setting the PgHdr.needSync flag.
+    **
+    ** If the attempt to load the page into the page-cache fails, (due
+    ** to a malloc() or IO failure), clear the bit in the pInJournal[]
+    ** array. Otherwise, if the page is loaded and written again in
+    ** this transaction, it may be written to the database file before
+    ** it is synced into the journal file. This way, it may end up in
+    ** the journal file twice, but that is not a problem.
+    **
+    ** The sqlite3PagerGet() call may cause the journal to sync. So make
+    ** sure the Pager.needSync flag is set too.
+    */
+    int rc;
+    PgHdr *pPgHdr;
+    assert( pPager->needSync );
+    rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr);
+    if( rc!=SQLITE_OK ){
+      if( pPager->pInJournal && (int)needSyncPgno<=pPager->origDbSize ){
+        sqlite3BitvecClear(pPager->pInJournal, needSyncPgno);
+      }
+      pagerLeave(pPager);
+      return rc;
+    }
+    pPager->needSync = 1;
+    pPgHdr->needSync = 1;
+    pPgHdr->inJournal = 1;
+    makeDirty(pPgHdr);
+    sqlite3PagerUnref(pPgHdr);
+  }
+
+  pagerLeave(pPager);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Return a pointer to the data for the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *pPg){
+  return PGHDR_TO_DATA(pPg);
+}
+
+/*
+** Return a pointer to the Pager.nExtra bytes of "extra" space 
+** allocated along with the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *pPg){
+  Pager *pPager = pPg->pPager;
+  return (pPager?PGHDR_TO_EXTRA(pPg, pPager):0);
+}
+
+/*
+** Get/set the locking-mode for this pager. Parameter eMode must be one
+** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or 
+** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
+** the locking-mode is set to the value specified.
+**
+** The returned value is either PAGER_LOCKINGMODE_NORMAL or
+** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
+** locking-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *pPager, int eMode){
+  assert( eMode==PAGER_LOCKINGMODE_QUERY
+            || eMode==PAGER_LOCKINGMODE_NORMAL
+            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_QUERY<0 );
+  assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
+  if( eMode>=0 && !pPager->tempFile ){
+    pPager->exclusiveMode = eMode;
+  }
+  return (int)pPager->exclusiveMode;
+}
+
+/*
+** Get/set the journal-mode for this pager. Parameter eMode must be one
+** of PAGER_JOURNALMODE_QUERY, PAGER_JOURNALMODE_DELETE or 
+** PAGER_JOURNALMODE_PERSIST. If the parameter is not _QUERY, then
+** the journal-mode is set to the value specified.
+**
+** The returned value is either PAGER_JOURNALMODE_DELETE or
+** PAGER_JOURNALMODE_PERSIST, indicating the current (possibly updated)
+** journal-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerJournalMode(Pager *pPager, int eMode){
+  assert( eMode==PAGER_JOURNALMODE_QUERY
+            || eMode==PAGER_JOURNALMODE_DELETE
+            || eMode==PAGER_JOURNALMODE_PERSIST
+            || eMode==PAGER_JOURNALMODE_OFF );
+  assert( PAGER_JOURNALMODE_QUERY<0 );
+  assert( PAGER_JOURNALMODE_DELETE>=0 && PAGER_JOURNALMODE_PERSIST>=0 );
+  if( eMode>=0 ){
+    pPager->journalMode = eMode;
+  }
+  return (int)pPager->journalMode;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Print a listing of all referenced pages and their ref count.
+*/
+SQLITE_PRIVATE void sqlite3PagerRefdump(Pager *pPager){
+  PgHdr *pPg;
+  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
+    if( pPg->nRef<=0 ) continue;
+    sqlite3DebugPrintf("PAGE %3d addr=%p nRef=%d\n", 
+       pPg->pgno, PGHDR_TO_DATA(pPg), pPg->nRef);
+  }
+}
+#endif
+
+#endif /* SQLITE_OMIT_DISKIO */
+
+/************** End of pager.c ***********************************************/
+/************** Begin file btmutex.c *****************************************/
+/*
+** 2007 August 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** $Id: btmutex.c,v 1.9 2008/01/23 12:52:41 drh Exp $
+**
+** This file contains code used to implement mutexes on Btree objects.
+** This code really belongs in btree.c.  But btree.c is getting too
+** big and we want to break it down some.  This packaged seemed like
+** a good breakout.
+*/
+/************** Include btreeInt.h in the middle of btmutex.c ****************/
+/************** Begin file btreeInt.h ****************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** $Id: btreeInt.h,v 1.21 2008/04/24 19:15:10 shane Exp $
+**
+** This file implements a external (disk-based) database using BTrees.
+** For a detailed discussion of BTrees, refer to
+**
+**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
+**     "Sorting And Searching", pages 473-480. Addison-Wesley
+**     Publishing Company, Reading, Massachusetts.
+**
+** The basic idea is that each page of the file contains N database
+** entries and N+1 pointers to subpages.
+**
+**   ----------------------------------------------------------------
+**   |  Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) |
+**   ----------------------------------------------------------------
+**
+** All of the keys on the page that Ptr(0) points to have values less
+** than Key(0).  All of the keys on page Ptr(1) and its subpages have
+** values greater than Key(0) and less than Key(1).  All of the keys
+** on Ptr(N) and its subpages have values greater than Key(N-1).  And
+** so forth.
+**
+** Finding a particular key requires reading O(log(M)) pages from the 
+** disk where M is the number of entries in the tree.
+**
+** In this implementation, a single file can hold one or more separate 
+** BTrees.  Each BTree is identified by the index of its root page.  The
+** key and data for any entry are combined to form the "payload".  A
+** fixed amount of payload can be carried directly on the database
+** page.  If the payload is larger than the preset amount then surplus
+** bytes are stored on overflow pages.  The payload for an entry
+** and the preceding pointer are combined to form a "Cell".  Each 
+** page has a small header which contains the Ptr(N) pointer and other
+** information such as the size of key and data.
+**
+** FORMAT DETAILS
+**
+** The file is divided into pages.  The first page is called page 1,
+** the second is page 2, and so forth.  A page number of zero indicates
+** "no such page".  The page size can be anything between 512 and 65536.
+** Each page can be either a btree page, a freelist page or an overflow
+** page.
+**
+** The first page is always a btree page.  The first 100 bytes of the first
+** page contain a special header (the "file header") that describes the file.
+** The format of the file header is as follows:
+**
+**   OFFSET   SIZE    DESCRIPTION
+**      0      16     Header string: "SQLite format 3\000"
+**     16       2     Page size in bytes.  
+**     18       1     File format write version
+**     19       1     File format read version
+**     20       1     Bytes of unused space at the end of each page
+**     21       1     Max embedded payload fraction
+**     22       1     Min embedded payload fraction
+**     23       1     Min leaf payload fraction
+**     24       4     File change counter
+**     28       4     Reserved for future use
+**     32       4     First freelist page
+**     36       4     Number of freelist pages in the file
+**     40      60     15 4-byte meta values passed to higher layers
+**
+** All of the integer values are big-endian (most significant byte first).
+**
+** The file change counter is incremented when the database is changed
+** This counter allows other processes to know when the file has changed
+** and thus when they need to flush their cache.
+**
+** The max embedded payload fraction is the amount of the total usable
+** space in a page that can be consumed by a single cell for standard
+** B-tree (non-LEAFDATA) tables.  A value of 255 means 100%.  The default
+** is to limit the maximum cell size so that at least 4 cells will fit
+** on one page.  Thus the default max embedded payload fraction is 64.
+**
+** If the payload for a cell is larger than the max payload, then extra
+** payload is spilled to overflow pages.  Once an overflow page is allocated,
+** as many bytes as possible are moved into the overflow pages without letting
+** the cell size drop below the min embedded payload fraction.
+**
+** The min leaf payload fraction is like the min embedded payload fraction
+** except that it applies to leaf nodes in a LEAFDATA tree.  The maximum
+** payload fraction for a LEAFDATA tree is always 100% (or 255) and it
+** not specified in the header.
+**
+** Each btree pages is divided into three sections:  The header, the
+** cell pointer array, and the cell content area.  Page 1 also has a 100-byte
+** file header that occurs before the page header.
+**
+**      |----------------|
+**      | file header    |   100 bytes.  Page 1 only.
+**      |----------------|
+**      | page header    |   8 bytes for leaves.  12 bytes for interior nodes
+**      |----------------|
+**      | cell pointer   |   |  2 bytes per cell.  Sorted order.
+**      | array          |   |  Grows downward
+**      |                |   v
+**      |----------------|
+**      | unallocated    |
+**      | space          |
+**      |----------------|   ^  Grows upwards
+**      | cell content   |   |  Arbitrary order interspersed with freeblocks.
+**      | area           |   |  and free space fragments.
+**      |----------------|
+**
+** The page headers looks like this:
+**
+**   OFFSET   SIZE     DESCRIPTION
+**      0       1      Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf
+**      1       2      byte offset to the first freeblock
+**      3       2      number of cells on this page
+**      5       2      first byte of the cell content area
+**      7       1      number of fragmented free bytes
+**      8       4      Right child (the Ptr(N) value).  Omitted on leaves.
+**
+** The flags define the format of this btree page.  The leaf flag means that
+** this page has no children.  The zerodata flag means that this page carries
+** only keys and no data.  The intkey flag means that the key is a integer
+** which is stored in the key size entry of the cell header rather than in
+** the payload area.
+**
+** The cell pointer array begins on the first byte after the page header.
+** The cell pointer array contains zero or more 2-byte numbers which are
+** offsets from the beginning of the page to the cell content in the cell
+** content area.  The cell pointers occur in sorted order.  The system strives
+** to keep free space after the last cell pointer so that new cells can
+** be easily added without having to defragment the page.
+**
+** Cell content is stored at the very end of the page and grows toward the
+** beginning of the page.
+**
+** Unused space within the cell content area is collected into a linked list of
+** freeblocks.  Each freeblock is at least 4 bytes in size.  The byte offset
+** to the first freeblock is given in the header.  Freeblocks occur in
+** increasing order.  Because a freeblock must be at least 4 bytes in size,
+** any group of 3 or fewer unused bytes in the cell content area cannot
+** exist on the freeblock chain.  A group of 3 or fewer free bytes is called
+** a fragment.  The total number of bytes in all fragments is recorded.
+** in the page header at offset 7.
+**
+**    SIZE    DESCRIPTION
+**      2     Byte offset of the next freeblock
+**      2     Bytes in this freeblock
+**
+** Cells are of variable length.  Cells are stored in the cell content area at
+** the end of the page.  Pointers to the cells are in the cell pointer array
+** that immediately follows the page header.  Cells is not necessarily
+** contiguous or in order, but cell pointers are contiguous and in order.
+**
+** Cell content makes use of variable length integers.  A variable
+** length integer is 1 to 9 bytes where the lower 7 bits of each 
+** byte are used.  The integer consists of all bytes that have bit 8 set and
+** the first byte with bit 8 clear.  The most significant byte of the integer
+** appears first.  A variable-length integer may not be more than 9 bytes long.
+** As a special case, all 8 bytes of the 9th byte are used as data.  This
+** allows a 64-bit integer to be encoded in 9 bytes.
+**
+**    0x00                      becomes  0x00000000
+**    0x7f                      becomes  0x0000007f
+**    0x81 0x00                 becomes  0x00000080
+**    0x82 0x00                 becomes  0x00000100
+**    0x80 0x7f                 becomes  0x0000007f
+**    0x8a 0x91 0xd1 0xac 0x78  becomes  0x12345678
+**    0x81 0x81 0x81 0x81 0x01  becomes  0x10204081
+**
+** Variable length integers are used for rowids and to hold the number of
+** bytes of key and data in a btree cell.
+**
+** The content of a cell looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of the left child. Omitted if leaf flag is set.
+**     var    Number of bytes of data. Omitted if the zerodata flag is set.
+**     var    Number of bytes of key. Or the key itself if intkey flag is set.
+**      *     Payload
+**      4     First page of the overflow chain.  Omitted if no overflow
+**
+** Overflow pages form a linked list.  Each page except the last is completely
+** filled with data (pagesize - 4 bytes).  The last page can have as little
+** as 1 byte of data.
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next overflow page
+**      *     Data
+**
+** Freelist pages come in two subtypes: trunk pages and leaf pages.  The
+** file header points to the first in a linked list of trunk page.  Each trunk
+** page points to multiple leaf pages.  The content of a leaf page is
+** unspecified.  A trunk page looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next trunk page
+**      4     Number of leaf pointers on this page
+**      *     zero or more pages numbers of leaves
+*/
+
+/* Round up a number to the next larger multiple of 8.  This is used
+** to force 8-byte alignment on 64-bit architectures.
+*/
+#define ROUND8(x)   ((x+7)&~7)
+
+
+/* The following value is the maximum cell size assuming a maximum page
+** size give above.
+*/
+#define MX_CELL_SIZE(pBt)  (pBt->pageSize-8)
+
+/* The maximum number of cells on a single page of the database.  This
+** assumes a minimum cell size of 6 bytes  (4 bytes for the cell itself
+** plus 2 bytes for the index to the cell in the page header).  Such
+** small cells will be rare, but they are possible.
+*/
+#define MX_CELL(pBt) ((pBt->pageSize-8)/6)
+
+/* Forward declarations */
+typedef struct MemPage MemPage;
+typedef struct BtLock BtLock;
+
+/*
+** This is a magic string that appears at the beginning of every
+** SQLite database in order to identify the file as a real database.
+**
+** You can change this value at compile-time by specifying a
+** -DSQLITE_FILE_HEADER="..." on the compiler command-line.  The
+** header must be exactly 16 bytes including the zero-terminator so
+** the string itself should be 15 characters long.  If you change
+** the header, then your custom library will not be able to read 
+** databases generated by the standard tools and the standard tools
+** will not be able to read databases created by your custom library.
+*/
+#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */
+#  define SQLITE_FILE_HEADER "SQLite format 3"
+#endif
+
+/*
+** Page type flags.  An ORed combination of these flags appear as the
+** first byte of on-disk image of every BTree page.
+*/
+#define PTF_INTKEY    0x01
+#define PTF_ZERODATA  0x02
+#define PTF_LEAFDATA  0x04
+#define PTF_LEAF      0x08
+
+/*
+** As each page of the file is loaded into memory, an instance of the following
+** structure is appended and initialized to zero.  This structure stores
+** information about the page that is decoded from the raw file page.
+**
+** The pParent field points back to the parent page.  This allows us to
+** walk up the BTree from any leaf to the root.  Care must be taken to
+** unref() the parent page pointer when this page is no longer referenced.
+** The pageDestructor() routine handles that chore.
+**
+** Access to all fields of this structure is controlled by the mutex
+** stored in MemPage.pBt->mutex.
+*/
+struct MemPage {
+  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
+  u8 idxShift;         /* True if Cell indices have changed */
+  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
+  u8 intKey;           /* True if intkey flag is set */
+  u8 leaf;             /* True if leaf flag is set */
+  u8 zeroData;         /* True if table stores keys only */
+  u8 leafData;         /* True if tables stores data on leaves only */
+  u8 hasData;          /* True if this page stores data */
+  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
+  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
+  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
+  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
+  u16 cellOffset;      /* Index in aData of first cell pointer */
+  u16 idxParent;       /* Index in parent of this node */
+  u16 nFree;           /* Number of free bytes on the page */
+  u16 nCell;           /* Number of cells on this page, local and ovfl */
+  struct _OvflCell {   /* Cells that will not fit on aData[] */
+    u8 *pCell;          /* Pointers to the body of the overflow cell */
+    u16 idx;            /* Insert this cell before idx-th non-overflow cell */
+  } aOvfl[5];
+  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
+  u8 *aData;           /* Pointer to disk image of the page data */
+  DbPage *pDbPage;     /* Pager page handle */
+  Pgno pgno;           /* Page number for this page */
+  MemPage *pParent;    /* The parent of this page.  NULL for root */
+};
+
+/*
+** The in-memory image of a disk page has the auxiliary information appended
+** to the end.  EXTRA_SIZE is the number of bytes of space needed to hold
+** that extra information.
+*/
+#define EXTRA_SIZE sizeof(MemPage)
+
+/* A Btree handle
+**
+** A database connection contains a pointer to an instance of
+** this object for every database file that it has open.  This structure
+** is opaque to the database connection.  The database connection cannot
+** see the internals of this structure and only deals with pointers to
+** this structure.
+**
+** For some database files, the same underlying database cache might be 
+** shared between multiple connections.  In that case, each contection
+** has it own pointer to this object.  But each instance of this object
+** points to the same BtShared object.  The database cache and the
+** schema associated with the database file are all contained within
+** the BtShared object.
+**
+** All fields in this structure are accessed under sqlite3.mutex.
+** The pBt pointer itself may not be changed while there exists cursors 
+** in the referenced BtShared that point back to this Btree since those
+** cursors have to do go through this Btree to find their BtShared and
+** they often do so without holding sqlite3.mutex.
+*/
+struct Btree {
+  sqlite3 *db;       /* The database connection holding this btree */
+  BtShared *pBt;     /* Sharable content of this btree */
+  u8 inTrans;        /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
+  u8 sharable;       /* True if we can share pBt with another db */
+  u8 locked;         /* True if db currently has pBt locked */
+  int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
+  Btree *pNext;      /* List of other sharable Btrees from the same db */
+  Btree *pPrev;      /* Back pointer of the same list */
+};
+
+/*
+** Btree.inTrans may take one of the following values.
+**
+** If the shared-data extension is enabled, there may be multiple users
+** of the Btree structure. At most one of these may open a write transaction,
+** but any number may have active read transactions.
+*/
+#define TRANS_NONE  0
+#define TRANS_READ  1
+#define TRANS_WRITE 2
+
+/*
+** An instance of this object represents a single database file.
+** 
+** A single database file can be in use as the same time by two
+** or more database connections.  When two or more connections are
+** sharing the same database file, each connection has it own
+** private Btree object for the file and each of those Btrees points
+** to this one BtShared object.  BtShared.nRef is the number of
+** connections currently sharing this database file.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** mutex, except for nRef and pNext which are accessed under the
+** global SQLITE_MUTEX_STATIC_MASTER mutex.  The pPager field
+** may not be modified once it is initially set as long as nRef>0.
+** The pSchema field may be set once under BtShared.mutex and
+** thereafter is unchanged as long as nRef>0.
+*/
+struct BtShared {
+  Pager *pPager;        /* The page cache */
+  sqlite3 *db;          /* Database connection currently using this Btree */
+  BtCursor *pCursor;    /* A list of all open cursors */
+  MemPage *pPage1;      /* First page of the database */
+  u8 inStmt;            /* True if we are in a statement subtransaction */
+  u8 readOnly;          /* True if the underlying file is readonly */
+  u8 maxEmbedFrac;      /* Maximum payload as % of total page size */
+  u8 minEmbedFrac;      /* Minimum payload as % of total page size */
+  u8 minLeafFrac;       /* Minimum leaf payload as % of total page size */
+  u8 pageSizeFixed;     /* True if the page size can no longer be changed */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  u8 autoVacuum;        /* True if auto-vacuum is enabled */
+  u8 incrVacuum;        /* True if incr-vacuum is enabled */
+  Pgno nTrunc;          /* Non-zero if the db will be truncated (incr vacuum) */
+#endif
+  u16 pageSize;         /* Total number of bytes on a page */
+  u16 usableSize;       /* Number of usable bytes on each page */
+  int maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
+  int minLocal;         /* Minimum local payload in non-LEAFDATA tables */
+  int maxLeaf;          /* Maximum local payload in a LEAFDATA table */
+  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
+  u8 inTransaction;     /* Transaction state */
+  int nTransaction;     /* Number of open transactions (read + write) */
+  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
+  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
+  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */
+  BusyHandler busyHdr;  /* The busy handler for this btree */
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nRef;             /* Number of references to this structure */
+  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
+  BtLock *pLock;        /* List of locks held on this shared-btree struct */
+  Btree *pExclusive;    /* Btree with an EXCLUSIVE lock on the whole db */
+#endif
+  u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
+};
+
+/*
+** An instance of the following structure is used to hold information
+** about a cell.  The parseCellPtr() function fills in this structure
+** based on information extract from the raw disk page.
+*/
+typedef struct CellInfo CellInfo;
+struct CellInfo {
+  u8 *pCell;     /* Pointer to the start of cell content */
+  i64 nKey;      /* The key for INTKEY tables, or number of bytes in key */
+  u32 nData;     /* Number of bytes of data */
+  u32 nPayload;  /* Total amount of payload */
+  u16 nHeader;   /* Size of the cell content header in bytes */
+  u16 nLocal;    /* Amount of payload held locally */
+  u16 iOverflow; /* Offset to overflow page number.  Zero if no overflow */
+  u16 nSize;     /* Size of the cell content on the main b-tree page */
+};
+
+/*
+** A cursor is a pointer to a particular entry within a particular
+** b-tree within a database file.
+**
+** The entry is identified by its MemPage and the index in
+** MemPage.aCell[] of the entry.
+**
+** When a single database file can shared by two more database connections,
+** but cursors cannot be shared.  Each cursor is associated with a
+** particular database connection identified BtCursor.pBtree.db.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** found at self->pBt->mutex. 
+*/
+struct BtCursor {
+  Btree *pBtree;            /* The Btree to which this cursor belongs */
+  BtShared *pBt;            /* The BtShared this cursor points to */
+  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
+  struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
+  Pgno pgnoRoot;            /* The root page of this tree */
+  MemPage *pPage;           /* Page that contains the entry */
+  int idx;                  /* Index of the entry in pPage->aCell[] */
+  CellInfo info;            /* A parse of the cell we are pointing at */
+  u8 wrFlag;                /* True if writable */
+  u8 atLast;                /* Cursor pointing to the last entry */
+  u8 validNKey;             /* True if info.nKey is valid */
+  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
+  void *pKey;      /* Saved key that was cursor's last known position */
+  i64 nKey;        /* Size of pKey, or last integer key */
+  int skip;        /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */
+#ifndef SQLITE_OMIT_INCRBLOB
+  u8 isIncrblobHandle;      /* True if this cursor is an incr. io handle */
+  Pgno *aOverflow;          /* Cache of overflow page locations */
+#endif
+};
+
+/*
+** Potential values for BtCursor.eState.
+**
+** CURSOR_VALID:
+**   Cursor points to a valid entry. getPayload() etc. may be called.
+**
+** CURSOR_INVALID:
+**   Cursor does not point to a valid entry. This can happen (for example) 
+**   because the table is empty or because BtreeCursorFirst() has not been
+**   called.
+**
+** CURSOR_REQUIRESEEK:
+**   The table that this cursor was opened on still exists, but has been 
+**   modified since the cursor was last used. The cursor position is saved
+**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in 
+**   this state, restoreOrClearCursorPosition() can be called to attempt to
+**   seek the cursor to the saved position.
+**
+** CURSOR_FAULT:
+**   A unrecoverable error (an I/O error or a malloc failure) has occurred
+**   on a different connection that shares the BtShared cache with this
+**   cursor.  The error has left the cache in an inconsistent state.
+**   Do nothing else with this cursor.  Any attempt to use the cursor
+**   should return the error code stored in BtCursor.skip
+*/
+#define CURSOR_INVALID           0
+#define CURSOR_VALID             1
+#define CURSOR_REQUIRESEEK       2
+#define CURSOR_FAULT             3
+
+/*
+** The TRACE macro will print high-level status information about the
+** btree operation when the global variable sqlite3BtreeTrace is
+** enabled.
+*/
+#if SQLITE_TEST
+# define TRACE(X)   if( sqlite3BtreeTrace ){ printf X; fflush(stdout); }
+#else
+# define TRACE(X)
+#endif
+
+/* The database page the PENDING_BYTE occupies. This page is never used.
+** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They
+** should possibly be consolidated (presumably in pager.h).
+**
+** If disk I/O is omitted (meaning that the database is stored purely
+** in memory) then there is no pending byte.
+*/
+#ifdef SQLITE_OMIT_DISKIO
+# define PENDING_BYTE_PAGE(pBt)  0x7fffffff
+#else
+# define PENDING_BYTE_PAGE(pBt) ((PENDING_BYTE/(pBt)->pageSize)+1)
+#endif
+
+/*
+** A linked list of the following structures is stored at BtShared.pLock.
+** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor 
+** is opened on the table with root page BtShared.iTable. Locks are removed
+** from this list when a transaction is committed or rolled back, or when
+** a btree handle is closed.
+*/
+struct BtLock {
+  Btree *pBtree;        /* Btree handle holding this lock */
+  Pgno iTable;          /* Root page of table */
+  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
+  BtLock *pNext;        /* Next in BtShared.pLock list */
+};
+
+/* Candidate values for BtLock.eLock */
+#define READ_LOCK     1
+#define WRITE_LOCK    2
+
+/*
+** These macros define the location of the pointer-map entry for a 
+** database page. The first argument to each is the number of usable
+** bytes on each page of the database (often 1024). The second is the
+** page number to look up in the pointer map.
+**
+** PTRMAP_PAGENO returns the database page number of the pointer-map
+** page that stores the required pointer. PTRMAP_PTROFFSET returns
+** the offset of the requested map entry.
+**
+** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
+** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
+** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
+** this test.
+*/
+#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
+#define PTRMAP_PTROFFSET(pBt, pgno) (5*(pgno-ptrmapPageno(pBt, pgno)-1))
+#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))
+
+/*
+** The pointer map is a lookup table that identifies the parent page for
+** each child page in the database file.  The parent page is the page that
+** contains a pointer to the child.  Every page in the database contains
+** 0 or 1 parent pages.  (In this context 'database page' refers
+** to any page that is not part of the pointer map itself.)  Each pointer map
+** entry consists of a single byte 'type' and a 4 byte parent page number.
+** The PTRMAP_XXX identifiers below are the valid types.
+**
+** The purpose of the pointer map is to facility moving pages from one
+** position in the file to another as part of autovacuum.  When a page
+** is moved, the pointer in its parent must be updated to point to the
+** new location.  The pointer map is used to locate the parent page quickly.
+**
+** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
+**                  used in this case.
+**
+** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number 
+**                  is not used in this case.
+**
+** PTRMAP_OVERFLOW1: The database page is the first page in a list of 
+**                   overflow pages. The page number identifies the page that
+**                   contains the cell with a pointer to this overflow page.
+**
+** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
+**                   overflow pages. The page-number identifies the previous
+**                   page in the overflow page list.
+**
+** PTRMAP_BTREE: The database page is a non-root btree page. The page number
+**               identifies the parent page in the btree.
+*/
+#define PTRMAP_ROOTPAGE 1
+#define PTRMAP_FREEPAGE 2
+#define PTRMAP_OVERFLOW1 3
+#define PTRMAP_OVERFLOW2 4
+#define PTRMAP_BTREE 5
+
+/* A bunch of assert() statements to check the transaction state variables
+** of handle p (type Btree*) are internally consistent.
+*/
+#define btreeIntegrity(p) \
+  assert( p->pBt->inTransaction!=TRANS_NONE || p->pBt->nTransaction==0 ); \
+  assert( p->pBt->inTransaction>=p->inTrans ); 
+
+
+/*
+** The ISAUTOVACUUM macro is used within balance_nonroot() to determine
+** if the database supports auto-vacuum or not. Because it is used
+** within an expression that is an argument to another macro 
+** (sqliteMallocRaw), it is not possible to use conditional compilation.
+** So, this macro is defined instead.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+#define ISAUTOVACUUM (pBt->autoVacuum)
+#else
+#define ISAUTOVACUUM 0
+#endif
+
+
+/*
+** This structure is passed around through all the sanity checking routines
+** in order to keep track of some global state information.
+*/
+typedef struct IntegrityCk IntegrityCk;
+struct IntegrityCk {
+  BtShared *pBt;    /* The tree being checked out */
+  Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
+  int nPage;        /* Number of pages in the database */
+  int *anRef;       /* Number of times each page is referenced */
+  int mxErr;        /* Stop accumulating errors when this reaches zero */
+  char *zErrMsg;    /* An error message.  NULL if no errors seen. */
+  int nErr;         /* Number of messages written to zErrMsg so far */
+};
+
+/*
+** Read or write a two- and four-byte big-endian integer values.
+*/
+#define get2byte(x)   ((x)[0]<<8 | (x)[1])
+#define put2byte(p,v) ((p)[0] = (v)>>8, (p)[1] = (v))
+#define get4byte sqlite3Get4byte
+#define put4byte sqlite3Put4byte
+
+/*
+** Internal routines that should be accessed by the btree layer only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int);
+SQLITE_PRIVATE int sqlite3BtreeInitPage(MemPage *pPage, MemPage *pParent);
+SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*);
+SQLITE_PRIVATE void sqlite3BtreeParseCell(MemPage*, int, CellInfo*);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE u8 *sqlite3BtreeFindCell(MemPage *pPage, int iCell);
+#endif
+SQLITE_PRIVATE int sqlite3BtreeRestoreOrClearCursorPosition(BtCursor *pCur);
+SQLITE_PRIVATE void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur);
+SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur);
+SQLITE_PRIVATE int sqlite3BtreeIsRootPage(MemPage *pPage);
+SQLITE_PRIVATE void sqlite3BtreeMoveToParent(BtCursor *pCur);
+
+/************** End of btreeInt.h ********************************************/
+/************** Continuing where we left off in btmutex.c ********************/
+#if SQLITE_THREADSAFE && !defined(SQLITE_OMIT_SHARED_CACHE)
+
+
+/*
+** Enter a mutex on the given BTree object.
+**
+** If the object is not sharable, then no mutex is ever required
+** and this routine is a no-op.  The underlying mutex is non-recursive.
+** But we keep a reference count in Btree.wantToLock so the behavior
+** of this interface is recursive.
+**
+** To avoid deadlocks, multiple Btrees are locked in the same order
+** by all database connections.  The p->pNext is a list of other
+** Btrees belonging to the same database connection as the p Btree
+** which need to be locked after p.  If we cannot get a lock on
+** p, then first unlock all of the others on p->pNext, then wait
+** for the lock to become available on p, then relock all of the
+** subsequent Btrees that desire a lock.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  Btree *pLater;
+
+  /* Some basic sanity checking on the Btree.  The list of Btrees
+  ** connected by pNext and pPrev should be in sorted order by
+  ** Btree.pBt value. All elements of the list should belong to
+  ** the same connection. Only shared Btrees are on the list. */
+  assert( p->pNext==0 || p->pNext->pBt>p->pBt );
+  assert( p->pPrev==0 || p->pPrev->pBt<p->pBt );
+  assert( p->pNext==0 || p->pNext->db==p->db );
+  assert( p->pPrev==0 || p->pPrev->db==p->db );
+  assert( p->sharable || (p->pNext==0 && p->pPrev==0) );
+
+  /* Check for locking consistency */
+  assert( !p->locked || p->wantToLock>0 );
+  assert( p->sharable || p->wantToLock==0 );
+
+  /* We should already hold a lock on the database connection */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  if( !p->sharable ) return;
+  p->wantToLock++;
+  if( p->locked ) return;
+
+#ifndef SQLITE_MUTEX_NOOP
+  /* In most cases, we should be able to acquire the lock we
+  ** want without having to go throught the ascending lock
+  ** procedure that follows.  Just be sure not to block.
+  */
+  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
+    p->locked = 1;
+    return;
+  }
+
+  /* To avoid deadlock, first release all locks with a larger
+  ** BtShared address.  Then acquire our lock.  Then reacquire
+  ** the other BtShared locks that we used to hold in ascending
+  ** order.
+  */
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    assert( pLater->sharable );
+    assert( pLater->pNext==0 || pLater->pNext->pBt>pLater->pBt );
+    assert( !pLater->locked || pLater->wantToLock>0 );
+    if( pLater->locked ){
+      sqlite3_mutex_leave(pLater->pBt->mutex);
+      pLater->locked = 0;
+    }
+  }
+  sqlite3_mutex_enter(p->pBt->mutex);
+  p->locked = 1;
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    if( pLater->wantToLock ){
+      sqlite3_mutex_enter(pLater->pBt->mutex);
+      pLater->locked = 1;
+    }
+  }
+#endif /* SQLITE_MUTEX_NOOP */
+}
+
+/*
+** Exit the recursive mutex on a Btree.
+*/
+SQLITE_PRIVATE void sqlite3BtreeLeave(Btree *p){
+  if( p->sharable ){
+    assert( p->wantToLock>0 );
+    p->wantToLock--;
+    if( p->wantToLock==0 ){
+      assert( p->locked );
+      sqlite3_mutex_leave(p->pBt->mutex);
+      p->locked = 0;
+    }
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the BtShared mutex is held on the btree.  
+**
+** This routine makes no determination one why or another if the
+** database connection mutex is held.
+**
+** This routine is used only from within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsMutex(Btree *p){
+  return (p->sharable==0 ||
+             (p->locked && p->wantToLock && sqlite3_mutex_held(p->pBt->mutex)));
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Enter and leave a mutex on a Btree given a cursor owned by that
+** Btree.  These entry points are used by incremental I/O and can be
+** omitted if that module is not used.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnterCursor(BtCursor *pCur){
+  sqlite3BtreeEnter(pCur->pBtree);
+}
+SQLITE_PRIVATE void sqlite3BtreeLeaveCursor(BtCursor *pCur){
+  sqlite3BtreeLeave(pCur->pBtree);
+}
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+
+/*
+** Enter the mutex on every Btree associated with a database
+** connection.  This is needed (for example) prior to parsing
+** a statement since we will be comparing table and column names
+** against all schemas and we do not want those schemas being
+** reset out from under us.
+**
+** There is a corresponding leave-all procedures.
+**
+** Enter the mutexes in accending order by BtShared pointer address
+** to avoid the possibility of deadlock when two threads with
+** two or more btrees in common both try to lock all their btrees
+** at the same instant.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
+  int i;
+  Btree *p, *pLater;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p && p->sharable ){
+      p->wantToLock++;
+      if( !p->locked ){
+        assert( p->wantToLock==1 );
+        while( p->pPrev ) p = p->pPrev;
+        while( p->locked && p->pNext ) p = p->pNext;
+        for(pLater = p->pNext; pLater; pLater=pLater->pNext){
+          if( pLater->locked ){
+            sqlite3_mutex_leave(pLater->pBt->mutex);
+            pLater->locked = 0;
+          }
+        }
+        while( p ){
+          sqlite3_mutex_enter(p->pBt->mutex);
+          p->locked++;
+          p = p->pNext;
+        }
+      }
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3BtreeLeaveAll(sqlite3 *db){
+  int i;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p && p->sharable ){
+      assert( p->wantToLock>0 );
+      p->wantToLock--;
+      if( p->wantToLock==0 ){
+        assert( p->locked );
+        sqlite3_mutex_leave(p->pBt->mutex);
+        p->locked = 0;
+      }
+    }
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the current thread holds the database connection
+** mutex and all required BtShared mutexes.
+**
+** This routine is used inside assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsAllMutexes(sqlite3 *db){
+  int i;
+  if( !sqlite3_mutex_held(db->mutex) ){
+    return 0;
+  }
+  for(i=0; i<db->nDb; i++){
+    Btree *p;
+    p = db->aDb[i].pBt;
+    if( p && p->sharable &&
+         (p->wantToLock==0 || !sqlite3_mutex_held(p->pBt->mutex)) ){
+      return 0;
+    }
+  }
+  return 1;
+}
+#endif /* NDEBUG */
+
+/*
+** Potentially dd a new Btree pointer to a BtreeMutexArray.
+** Really only add the Btree if it can possibly be shared with
+** another database connection.
+**
+** The Btrees are kept in sorted order by pBtree->pBt.  That
+** way when we go to enter all the mutexes, we can enter them
+** in order without every having to backup and retry and without
+** worrying about deadlock.
+**
+** The number of shared btrees will always be small (usually 0 or 1)
+** so an insertion sort is an adequate algorithm here.
+*/
+SQLITE_PRIVATE void sqlite3BtreeMutexArrayInsert(BtreeMutexArray *pArray, Btree *pBtree){
+  int i, j;
+  BtShared *pBt;
+  if( pBtree==0 || pBtree->sharable==0 ) return;
+#ifndef NDEBUG
+  {
+    for(i=0; i<pArray->nMutex; i++){
+      assert( pArray->aBtree[i]!=pBtree );
+    }
+  }
+#endif
+  assert( pArray->nMutex>=0 );
+  assert( pArray->nMutex<sizeof(pArray->aBtree)/sizeof(pArray->aBtree[0])-1 );
+  pBt = pBtree->pBt;
+  for(i=0; i<pArray->nMutex; i++){
+    assert( pArray->aBtree[i]!=pBtree );
+    if( pArray->aBtree[i]->pBt>pBt ){
+      for(j=pArray->nMutex; j>i; j--){
+        pArray->aBtree[j] = pArray->aBtree[j-1];
+      }
+      pArray->aBtree[i] = pBtree;
+      pArray->nMutex++;
+      return;
+    }
+  }
+  pArray->aBtree[pArray->nMutex++] = pBtree;
+}
+
+/*
+** Enter the mutex of every btree in the array.  This routine is
+** called at the beginning of sqlite3VdbeExec().  The mutexes are
+** exited at the end of the same function.
+*/
+SQLITE_PRIVATE void sqlite3BtreeMutexArrayEnter(BtreeMutexArray *pArray){
+  int i;
+  for(i=0; i<pArray->nMutex; i++){
+    Btree *p = pArray->aBtree[i];
+    /* Some basic sanity checking */
+    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
+    assert( !p->locked || p->wantToLock>0 );
+
+    /* We should already hold a lock on the database connection */
+    assert( sqlite3_mutex_held(p->db->mutex) );
+
+    p->wantToLock++;
+    if( !p->locked && p->sharable ){
+      sqlite3_mutex_enter(p->pBt->mutex);
+      p->locked = 1;
+    }
+  }
+}
+
+/*
+** Leave the mutex of every btree in the group.
+*/
+SQLITE_PRIVATE void sqlite3BtreeMutexArrayLeave(BtreeMutexArray *pArray){
+  int i;
+  for(i=0; i<pArray->nMutex; i++){
+    Btree *p = pArray->aBtree[i];
+    /* Some basic sanity checking */
+    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
+    assert( p->locked || !p->sharable );
+    assert( p->wantToLock>0 );
+
+    /* We should already hold a lock on the database connection */
+    assert( sqlite3_mutex_held(p->db->mutex) );
+
+    p->wantToLock--;
+    if( p->wantToLock==0 && p->locked ){
+      sqlite3_mutex_leave(p->pBt->mutex);
+      p->locked = 0;
+    }
+  }
+}
+
+
+#endif  /* SQLITE_THREADSAFE && !SQLITE_OMIT_SHARED_CACHE */
+
+/************** End of btmutex.c *********************************************/
+/************** Begin file btree.c *******************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** $Id: btree.c,v 1.458 2008/05/09 16:57:51 danielk1977 Exp $
+**
+** This file implements a external (disk-based) database using BTrees.
+** See the header comment on "btreeInt.h" for additional information.
+** Including a description of file format and an overview of operation.
+*/
+
+/*
+** The header string that appears at the beginning of every
+** SQLite database.
+*/
+static const char zMagicHeader[] = SQLITE_FILE_HEADER;
+
+/*
+** Set this global variable to 1 to enable tracing using the TRACE
+** macro.
+*/
+#if SQLITE_TEST
+int sqlite3BtreeTrace=0;  /* True to enable tracing */
+#endif
+
+
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** A flag to indicate whether or not shared cache is enabled.  Also,
+** a list of BtShared objects that are eligible for participation
+** in shared cache.  The variables have file scope during normal builds,
+** but the test harness needs to access these variables so we make them
+** global for test builds.
+*/
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE BtShared *sqlite3SharedCacheList = 0;
+SQLITE_PRIVATE int sqlite3SharedCacheEnabled = 0;
+#else
+static BtShared *sqlite3SharedCacheList = 0;
+static int sqlite3SharedCacheEnabled = 0;
+#endif
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Enable or disable the shared pager and schema features.
+**
+** This routine has no effect on existing database connections.
+** The shared cache setting effects only future calls to
+** sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2().
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int enable){
+  sqlite3SharedCacheEnabled = enable;
+  return SQLITE_OK;
+}
+#endif
+
+
+/*
+** Forward declaration
+*/
+static int checkReadLocks(Btree*,Pgno,BtCursor*);
+
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  /*
+  ** The functions queryTableLock(), lockTable() and unlockAllTables()
+  ** manipulate entries in the BtShared.pLock linked list used to store
+  ** shared-cache table level locks. If the library is compiled with the
+  ** shared-cache feature disabled, then there is only ever one user
+  ** of each BtShared structure and so this locking is not necessary. 
+  ** So define the lock related functions as no-ops.
+  */
+  #define queryTableLock(a,b,c) SQLITE_OK
+  #define lockTable(a,b,c) SQLITE_OK
+  #define unlockAllTables(a)
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Query to see if btree handle p may obtain a lock of type eLock 
+** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
+** SQLITE_OK if the lock may be obtained (by calling lockTable()), or
+** SQLITE_LOCKED if not.
+*/
+static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pIter;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  
+  /* This is a no-op if the shared-cache is not enabled */
+  if( !p->sharable ){
+    return SQLITE_OK;
+  }
+
+  /* If some other connection is holding an exclusive lock, the
+  ** requested lock may not be obtained.
+  */
+  if( pBt->pExclusive && pBt->pExclusive!=p ){
+    return SQLITE_LOCKED;
+  }
+
+  /* This (along with lockTable()) is where the ReadUncommitted flag is
+  ** dealt with. If the caller is querying for a read-lock and the flag is
+  ** set, it is unconditionally granted - even if there are write-locks
+  ** on the table. If a write-lock is requested, the ReadUncommitted flag
+  ** is not considered.
+  **
+  ** In function lockTable(), if a read-lock is demanded and the 
+  ** ReadUncommitted flag is set, no entry is added to the locks list 
+  ** (BtShared.pLock).
+  **
+  ** To summarize: If the ReadUncommitted flag is set, then read cursors do
+  ** not create or respect table locks. The locking procedure for a 
+  ** write-cursor does not change.
+  */
+  if( 
+    !p->db || 
+    0==(p->db->flags&SQLITE_ReadUncommitted) || 
+    eLock==WRITE_LOCK ||
+    iTab==MASTER_ROOT
+  ){
+    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+      if( pIter->pBtree!=p && pIter->iTable==iTab && 
+          (pIter->eLock!=eLock || eLock!=READ_LOCK) ){
+        return SQLITE_LOCKED;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Add a lock on the table with root-page iTable to the shared-btree used
+** by Btree handle p. Parameter eLock must be either READ_LOCK or 
+** WRITE_LOCK.
+**
+** SQLITE_OK is returned if the lock is added successfully. SQLITE_BUSY and
+** SQLITE_NOMEM may also be returned.
+*/
+static int lockTable(Btree *p, Pgno iTable, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pLock = 0;
+  BtLock *pIter;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+
+  /* This is a no-op if the shared-cache is not enabled */
+  if( !p->sharable ){
+    return SQLITE_OK;
+  }
+
+  assert( SQLITE_OK==queryTableLock(p, iTable, eLock) );
+
+  /* If the read-uncommitted flag is set and a read-lock is requested,
+  ** return early without adding an entry to the BtShared.pLock list. See
+  ** comment in function queryTableLock() for more info on handling 
+  ** the ReadUncommitted flag.
+  */
+  if( 
+    (p->db) && 
+    (p->db->flags&SQLITE_ReadUncommitted) && 
+    (eLock==READ_LOCK) &&
+    iTable!=MASTER_ROOT
+  ){
+    return SQLITE_OK;
+  }
+
+  /* First search the list for an existing lock on this table. */
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    if( pIter->iTable==iTable && pIter->pBtree==p ){
+      pLock = pIter;
+      break;
+    }
+  }
+
+  /* If the above search did not find a BtLock struct associating Btree p
+  ** with table iTable, allocate one and link it into the list.
+  */
+  if( !pLock ){
+    pLock = (BtLock *)sqlite3MallocZero(sizeof(BtLock));
+    if( !pLock ){
+      return SQLITE_NOMEM;
+    }
+    pLock->iTable = iTable;
+    pLock->pBtree = p;
+    pLock->pNext = pBt->pLock;
+    pBt->pLock = pLock;
+  }
+
+  /* Set the BtLock.eLock variable to the maximum of the current lock
+  ** and the requested lock. This means if a write-lock was already held
+  ** and a read-lock requested, we don't incorrectly downgrade the lock.
+  */
+  assert( WRITE_LOCK>READ_LOCK );
+  if( eLock>pLock->eLock ){
+    pLock->eLock = eLock;
+  }
+
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Release all the table locks (locks obtained via calls to the lockTable()
+** procedure) held by Btree handle p.
+*/
+static void unlockAllTables(Btree *p){
+  BtShared *pBt = p->pBt;
+  BtLock **ppIter = &pBt->pLock;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( p->sharable || 0==*ppIter );
+
+  while( *ppIter ){
+    BtLock *pLock = *ppIter;
+    assert( pBt->pExclusive==0 || pBt->pExclusive==pLock->pBtree );
+    if( pLock->pBtree==p ){
+      *ppIter = pLock->pNext;
+      sqlite3_free(pLock);
+    }else{
+      ppIter = &pLock->pNext;
+    }
+  }
+
+  if( pBt->pExclusive==p ){
+    pBt->pExclusive = 0;
+  }
+}
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+static void releasePage(MemPage *pPage);  /* Forward reference */
+
+/*
+** Verify that the cursor holds a mutex on the BtShared
+*/
+#ifndef NDEBUG
+static int cursorHoldsMutex(BtCursor *p){
+  return sqlite3_mutex_held(p->pBt->mutex);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Invalidate the overflow page-list cache for cursor pCur, if any.
+*/
+static void invalidateOverflowCache(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  sqlite3_free(pCur->aOverflow);
+  pCur->aOverflow = 0;
+}
+
+/*
+** Invalidate the overflow page-list cache for all cursors opened
+** on the shared btree structure pBt.
+*/
+static void invalidateAllOverflowCache(BtShared *pBt){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    invalidateOverflowCache(p);
+  }
+}
+#else
+  #define invalidateOverflowCache(x)
+  #define invalidateAllOverflowCache(x)
+#endif
+
+/*
+** Save the current cursor position in the variables BtCursor.nKey 
+** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
+*/
+static int saveCursorPosition(BtCursor *pCur){
+  int rc;
+
+  assert( CURSOR_VALID==pCur->eState );
+  assert( 0==pCur->pKey );
+  assert( cursorHoldsMutex(pCur) );
+
+  rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
+
+  /* If this is an intKey table, then the above call to BtreeKeySize()
+  ** stores the integer key in pCur->nKey. In this case this value is
+  ** all that is required. Otherwise, if pCur is not open on an intKey
+  ** table, then malloc space for and store the pCur->nKey bytes of key 
+  ** data.
+  */
+  if( rc==SQLITE_OK && 0==pCur->pPage->intKey){
+    void *pKey = sqlite3_malloc(pCur->nKey);
+    if( pKey ){
+      rc = sqlite3BtreeKey(pCur, 0, pCur->nKey, pKey);
+      if( rc==SQLITE_OK ){
+        pCur->pKey = pKey;
+      }else{
+        sqlite3_free(pKey);
+      }
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  assert( !pCur->pPage->intKey || !pCur->pKey );
+
+  if( rc==SQLITE_OK ){
+    releasePage(pCur->pPage);
+    pCur->pPage = 0;
+    pCur->eState = CURSOR_REQUIRESEEK;
+  }
+
+  invalidateOverflowCache(pCur);
+  return rc;
+}
+
+/*
+** Save the positions of all cursors except pExcept open on the table 
+** with root-page iRoot. Usually, this is called just before cursor
+** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
+*/
+static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pExcept==0 || pExcept->pBt==pBt );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) && 
+        p->eState==CURSOR_VALID ){
+      int rc = saveCursorPosition(p);
+      if( SQLITE_OK!=rc ){
+        return rc;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Clear the current cursor position.
+*/
+static void clearCursorPosition(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  sqlite3_free(pCur->pKey);
+  pCur->pKey = 0;
+  pCur->eState = CURSOR_INVALID;
+}
+
+/*
+** Restore the cursor to the position it was in (or as close to as possible)
+** when saveCursorPosition() was called. Note that this call deletes the 
+** saved position info stored by saveCursorPosition(), so there can be
+** at most one effective restoreOrClearCursorPosition() call after each 
+** saveCursorPosition().
+**
+** If the second argument argument - doSeek - is false, then instead of 
+** returning the cursor to its saved position, any saved position is deleted
+** and the cursor state set to CURSOR_INVALID.
+*/
+SQLITE_PRIVATE int sqlite3BtreeRestoreOrClearCursorPosition(BtCursor *pCur){
+  int rc;
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState>=CURSOR_REQUIRESEEK );
+  if( pCur->eState==CURSOR_FAULT ){
+    return pCur->skip;
+  }
+#ifndef SQLITE_OMIT_INCRBLOB
+  if( pCur->isIncrblobHandle ){
+    return SQLITE_ABORT;
+  }
+#endif
+  pCur->eState = CURSOR_INVALID;
+  rc = sqlite3BtreeMoveto(pCur, pCur->pKey, 0, pCur->nKey, 0, &pCur->skip);
+  if( rc==SQLITE_OK ){
+    sqlite3_free(pCur->pKey);
+    pCur->pKey = 0;
+    assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_INVALID );
+  }
+  return rc;
+}
+
+#define restoreOrClearCursorPosition(p) \
+  (p->eState>=CURSOR_REQUIRESEEK ? \
+         sqlite3BtreeRestoreOrClearCursorPosition(p) : \
+         SQLITE_OK)
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Given a page number of a regular database page, return the page
+** number for the pointer-map page that contains the entry for the
+** input page number.
+*/
+static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
+  int nPagesPerMapPage, iPtrMap, ret;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  nPagesPerMapPage = (pBt->usableSize/5)+1;
+  iPtrMap = (pgno-2)/nPagesPerMapPage;
+  ret = (iPtrMap*nPagesPerMapPage) + 2; 
+  if( ret==PENDING_BYTE_PAGE(pBt) ){
+    ret++;
+  }
+  return ret;
+}
+
+/*
+** Write an entry into the pointer map.
+**
+** This routine updates the pointer map entry for page number 'key'
+** so that it maps to type 'eType' and parent page number 'pgno'.
+** An error code is returned if something goes wrong, otherwise SQLITE_OK.
+*/
+static int ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent){
+  DbPage *pDbPage;  /* The pointer map page */
+  u8 *pPtrmap;      /* The pointer map data */
+  Pgno iPtrmap;     /* The pointer map page number */
+  int offset;       /* Offset in pointer map page */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  /* The master-journal page number must never be used as a pointer map page */
+  assert( 0==PTRMAP_ISPAGE(pBt, PENDING_BYTE_PAGE(pBt)) );
+
+  assert( pBt->autoVacuum );
+  if( key==0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  offset = PTRMAP_PTROFFSET(pBt, key);
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  if( eType!=pPtrmap[offset] || get4byte(&pPtrmap[offset+1])!=parent ){
+    TRACE(("PTRMAP_UPDATE: %d->(%d,%d)\n", key, eType, parent));
+    rc = sqlite3PagerWrite(pDbPage);
+    if( rc==SQLITE_OK ){
+      pPtrmap[offset] = eType;
+      put4byte(&pPtrmap[offset+1], parent);
+    }
+  }
+
+  sqlite3PagerUnref(pDbPage);
+  return rc;
+}
+
+/*
+** Read an entry from the pointer map.
+**
+** This routine retrieves the pointer map entry for page 'key', writing
+** the type and parent page number to *pEType and *pPgno respectively.
+** An error code is returned if something goes wrong, otherwise SQLITE_OK.
+*/
+static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
+  DbPage *pDbPage;   /* The pointer map page */
+  int iPtrmap;       /* Pointer map page index */
+  u8 *pPtrmap;       /* Pointer map page data */
+  int offset;        /* Offset of entry in pointer map */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage);
+  if( rc!=0 ){
+    return rc;
+  }
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  offset = PTRMAP_PTROFFSET(pBt, key);
+  assert( pEType!=0 );
+  *pEType = pPtrmap[offset];
+  if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);
+
+  sqlite3PagerUnref(pDbPage);
+  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT_BKPT;
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OMIT_AUTOVACUUM */
+
+/*
+** Given a btree page and a cell index (0 means the first cell on
+** the page, 1 means the second cell, and so forth) return a pointer
+** to the cell content.
+**
+** This routine works only for pages that do not contain overflow cells.
+*/
+#define findCell(pPage, iCell) \
+  ((pPage)->aData + get2byte(&(pPage)->aData[(pPage)->cellOffset+2*(iCell)]))
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE u8 *sqlite3BtreeFindCell(MemPage *pPage, int iCell){
+  assert( iCell>=0 );
+  assert( iCell<get2byte(&pPage->aData[pPage->hdrOffset+3]) );
+  return findCell(pPage, iCell);
+}
+#endif
+
+/*
+** This a more complex version of sqlite3BtreeFindCell() that works for
+** pages that do contain overflow cells.  See insert
+*/
+static u8 *findOverflowCell(MemPage *pPage, int iCell){
+  int i;
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  for(i=pPage->nOverflow-1; i>=0; i--){
+    int k;
+    struct _OvflCell *pOvfl;
+    pOvfl = &pPage->aOvfl[i];
+    k = pOvfl->idx;
+    if( k<=iCell ){
+      if( k==iCell ){
+        return pOvfl->pCell;
+      }
+      iCell--;
+    }
+  }
+  return findCell(pPage, iCell);
+}
+
+/*
+** Parse a cell content block and fill in the CellInfo structure.  There
+** are two versions of this function.  sqlite3BtreeParseCell() takes a 
+** cell index as the second argument and sqlite3BtreeParseCellPtr() 
+** takes a pointer to the body of the cell as its second argument.
+**
+** Within this file, the parseCell() macro can be called instead of
+** sqlite3BtreeParseCellPtr(). Using some compilers, this will be faster.
+*/
+SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  int n;                  /* Number bytes in cell content header */
+  u32 nPayload;           /* Number of bytes of cell payload */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  pInfo->pCell = pCell;
+  assert( pPage->leaf==0 || pPage->leaf==1 );
+  n = pPage->childPtrSize;
+  assert( n==4-4*pPage->leaf );
+  if( pPage->hasData ){
+    n += getVarint32(&pCell[n], nPayload);
+  }else{
+    nPayload = 0;
+  }
+  pInfo->nData = nPayload;
+  if( pPage->intKey ){
+    n += getVarint(&pCell[n], (u64 *)&pInfo->nKey);
+  }else{
+    u32 x;
+    n += getVarint32(&pCell[n], x);
+    pInfo->nKey = x;
+    nPayload += x;
+  }
+  pInfo->nPayload = nPayload;
+  pInfo->nHeader = n;
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the (easy) common case where the entire payload fits
+    ** on the local page.  No overflow is required.
+    */
+    int nSize;          /* Total size of cell content in bytes */
+    pInfo->nLocal = nPayload;
+    pInfo->iOverflow = 0;
+    nSize = nPayload + n;
+    if( nSize<4 ){
+      nSize = 4;        /* Minimum cell size is 4 */
+    }
+    pInfo->nSize = nSize;
+  }else{
+    /* If the payload will not fit completely on the local page, we have
+    ** to decide how much to store locally and how much to spill onto
+    ** overflow pages.  The strategy is to minimize the amount of unused
+    ** space on overflow pages while keeping the amount of local storage
+    ** in between minLocal and maxLocal.
+    **
+    ** Warning:  changing the way overflow payload is distributed in any
+    ** way will result in an incompatible file format.
+    */
+    int minLocal;  /* Minimum amount of payload held locally */
+    int maxLocal;  /* Maximum amount of payload held locally */
+    int surplus;   /* Overflow payload available for local storage */
+
+    minLocal = pPage->minLocal;
+    maxLocal = pPage->maxLocal;
+    surplus = minLocal + (nPayload - minLocal)%(pPage->pBt->usableSize - 4);
+    if( surplus <= maxLocal ){
+      pInfo->nLocal = surplus;
+    }else{
+      pInfo->nLocal = minLocal;
+    }
+    pInfo->iOverflow = pInfo->nLocal + n;
+    pInfo->nSize = pInfo->iOverflow + 4;
+  }
+}
+#define parseCell(pPage, iCell, pInfo) \
+  sqlite3BtreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
+SQLITE_PRIVATE void sqlite3BtreeParseCell(
+  MemPage *pPage,         /* Page containing the cell */
+  int iCell,              /* The cell index.  First cell is 0 */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  parseCell(pPage, iCell, pInfo);
+}
+
+/*
+** Compute the total number of bytes that a Cell needs in the cell
+** data area of the btree-page.  The return number includes the cell
+** data header and the local payload, but not any overflow page or
+** the space used by the cell pointer.
+*/
+#ifndef NDEBUG
+static u16 cellSize(MemPage *pPage, int iCell){
+  CellInfo info;
+  sqlite3BtreeParseCell(pPage, iCell, &info);
+  return info.nSize;
+}
+#endif
+static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
+  CellInfo info;
+  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  return info.nSize;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** If the cell pCell, part of page pPage contains a pointer
+** to an overflow page, insert an entry into the pointer-map
+** for the overflow page.
+*/
+static int ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell){
+  if( pCell ){
+    CellInfo info;
+    sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+    assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
+    if( (info.nData+(pPage->intKey?0:info.nKey))>info.nLocal ){
+      Pgno ovfl = get4byte(&pCell[info.iOverflow]);
+      return ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno);
+    }
+  }
+  return SQLITE_OK;
+}
+/*
+** If the cell with index iCell on page pPage contains a pointer
+** to an overflow page, insert an entry into the pointer-map
+** for the overflow page.
+*/
+static int ptrmapPutOvfl(MemPage *pPage, int iCell){
+  u8 *pCell;
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pCell = findOverflowCell(pPage, iCell);
+  return ptrmapPutOvflPtr(pPage, pCell);
+}
+#endif
+
+
+/*
+** Defragment the page given.  All Cells are moved to the
+** end of the page and all free space is collected into one
+** big FreeBlk that occurs in between the header and cell
+** pointer array and the cell content area.
+*/
+static int defragmentPage(MemPage *pPage){
+  int i;                     /* Loop counter */
+  int pc;                    /* Address of a i-th cell */
+  int addr;                  /* Offset of first byte after cell pointer array */
+  int hdr;                   /* Offset to the page header */
+  int size;                  /* Size of a cell */
+  int usableSize;            /* Number of usable bytes on a page */
+  int cellOffset;            /* Offset to the cell pointer array */
+  int brk;                   /* Offset to the cell content area */
+  int nCell;                 /* Number of cells on the page */
+  unsigned char *data;       /* The page data */
+  unsigned char *temp;       /* Temp area for cell content */
+
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
+  assert( pPage->nOverflow==0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  cellOffset = pPage->cellOffset;
+  nCell = pPage->nCell;
+  assert( nCell==get2byte(&data[hdr+3]) );
+  usableSize = pPage->pBt->usableSize;
+  brk = get2byte(&data[hdr+5]);
+  memcpy(&temp[brk], &data[brk], usableSize - brk);
+  brk = usableSize;
+  for(i=0; i<nCell; i++){
+    u8 *pAddr;     /* The i-th cell pointer */
+    pAddr = &data[cellOffset + i*2];
+    pc = get2byte(pAddr);
+    assert( pc<pPage->pBt->usableSize );
+    size = cellSizePtr(pPage, &temp[pc]);
+    brk -= size;
+    memcpy(&data[brk], &temp[pc], size);
+    put2byte(pAddr, brk);
+  }
+  assert( brk>=cellOffset+2*nCell );
+  put2byte(&data[hdr+5], brk);
+  data[hdr+1] = 0;
+  data[hdr+2] = 0;
+  data[hdr+7] = 0;
+  addr = cellOffset+2*nCell;
+  memset(&data[addr], 0, brk-addr);
+  return SQLITE_OK;
+}
+
+/*
+** Allocate nByte bytes of space on a page.
+**
+** Return the index into pPage->aData[] of the first byte of
+** the new allocation. Or return 0 if there is not enough free
+** space on the page to satisfy the allocation request.
+**
+** If the page contains nBytes of free space but does not contain
+** nBytes of contiguous free space, then this routine automatically
+** calls defragementPage() to consolidate all free space before 
+** allocating the new chunk.
+*/
+static int allocateSpace(MemPage *pPage, int nByte){
+  int addr, pc, hdr;
+  int size;
+  int nFrag;
+  int top;
+  int nCell;
+  int cellOffset;
+  unsigned char *data;
+  
+  data = pPage->aData;
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( nByte<4 ) nByte = 4;
+  if( pPage->nFree<nByte || pPage->nOverflow>0 ) return 0;
+  pPage->nFree -= nByte;
+  hdr = pPage->hdrOffset;
+
+  nFrag = data[hdr+7];
+  if( nFrag<60 ){
+    /* Search the freelist looking for a slot big enough to satisfy the
+    ** space request. */
+    addr = hdr+1;
+    while( (pc = get2byte(&data[addr]))>0 ){
+      size = get2byte(&data[pc+2]);
+      if( size>=nByte ){
+        if( size<nByte+4 ){
+          memcpy(&data[addr], &data[pc], 2);
+          data[hdr+7] = nFrag + size - nByte;
+          return pc;
+        }else{
+          put2byte(&data[pc+2], size-nByte);
+          return pc + size - nByte;
+        }
+      }
+      addr = pc;
+    }
+  }
+
+  /* Allocate memory from the gap in between the cell pointer array
+  ** and the cell content area.
+  */
+  top = get2byte(&data[hdr+5]);
+  nCell = get2byte(&data[hdr+3]);
+  cellOffset = pPage->cellOffset;
+  if( nFrag>=60 || cellOffset + 2*nCell > top - nByte ){
+    if( defragmentPage(pPage) ) return 0;
+    top = get2byte(&data[hdr+5]);
+  }
+  top -= nByte;
+  assert( cellOffset + 2*nCell <= top );
+  put2byte(&data[hdr+5], top);
+  return top;
+}
+
+/*
+** Return a section of the pPage->aData to the freelist.
+** The first byte of the new free block is pPage->aDisk[start]
+** and the size of the block is "size" bytes.
+**
+** Most of the effort here is involved in coalesing adjacent
+** free blocks into a single big free block.
+*/
+static void freeSpace(MemPage *pPage, int start, int size){
+  int addr, pbegin, hdr;
+  unsigned char *data = pPage->aData;
+
+  assert( pPage->pBt!=0 );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( start>=pPage->hdrOffset+6+(pPage->leaf?0:4) );
+  assert( (start + size)<=pPage->pBt->usableSize );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( size<4 ) size = 4;
+
+#ifdef SQLITE_SECURE_DELETE
+  /* Overwrite deleted information with zeros when the SECURE_DELETE 
+  ** option is enabled at compile-time */
+  memset(&data[start], 0, size);
+#endif
+
+  /* Add the space back into the linked list of freeblocks */
+  hdr = pPage->hdrOffset;
+  addr = hdr + 1;
+  while( (pbegin = get2byte(&data[addr]))<start && pbegin>0 ){
+    assert( pbegin<=pPage->pBt->usableSize-4 );
+    assert( pbegin>addr );
+    addr = pbegin;
+  }
+  assert( pbegin<=pPage->pBt->usableSize-4 );
+  assert( pbegin>addr || pbegin==0 );
+  put2byte(&data[addr], start);
+  put2byte(&data[start], pbegin);
+  put2byte(&data[start+2], size);
+  pPage->nFree += size;
+
+  /* Coalesce adjacent free blocks */
+  addr = pPage->hdrOffset + 1;
+  while( (pbegin = get2byte(&data[addr]))>0 ){
+    int pnext, psize;
+    assert( pbegin>addr );
+    assert( pbegin<=pPage->pBt->usableSize-4 );
+    pnext = get2byte(&data[pbegin]);
+    psize = get2byte(&data[pbegin+2]);
+    if( pbegin + psize + 3 >= pnext && pnext>0 ){
+      int frag = pnext - (pbegin+psize);
+      assert( frag<=data[pPage->hdrOffset+7] );
+      data[pPage->hdrOffset+7] -= frag;
+      put2byte(&data[pbegin], get2byte(&data[pnext]));
+      put2byte(&data[pbegin+2], pnext+get2byte(&data[pnext+2])-pbegin);
+    }else{
+      addr = pbegin;
+    }
+  }
+
+  /* If the cell content area begins with a freeblock, remove it. */
+  if( data[hdr+1]==data[hdr+5] && data[hdr+2]==data[hdr+6] ){
+    int top;
+    pbegin = get2byte(&data[hdr+1]);
+    memcpy(&data[hdr+1], &data[pbegin], 2);
+    top = get2byte(&data[hdr+5]);
+    put2byte(&data[hdr+5], top + get2byte(&data[pbegin+2]));
+  }
+}
+
+/*
+** Decode the flags byte (the first byte of the header) for a page
+** and initialize fields of the MemPage structure accordingly.
+*/
+static void decodeFlags(MemPage *pPage, int flagByte){
+  BtShared *pBt;     /* A copy of pPage->pBt */
+
+  assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pPage->intKey = (flagByte & (PTF_INTKEY|PTF_LEAFDATA))!=0;
+  pPage->zeroData = (flagByte & PTF_ZERODATA)!=0;
+  pPage->leaf = (flagByte & PTF_LEAF)!=0;
+  pPage->childPtrSize = 4*(pPage->leaf==0);
+  pBt = pPage->pBt;
+  if( flagByte & PTF_LEAFDATA ){
+    pPage->leafData = 1;
+    pPage->maxLocal = pBt->maxLeaf;
+    pPage->minLocal = pBt->minLeaf;
+  }else{
+    pPage->leafData = 0;
+    pPage->maxLocal = pBt->maxLocal;
+    pPage->minLocal = pBt->minLocal;
+  }
+  pPage->hasData = !(pPage->zeroData || (!pPage->leaf && pPage->leafData));
+}
+
+/*
+** Initialize the auxiliary information for a disk block.
+**
+** The pParent parameter must be a pointer to the MemPage which
+** is the parent of the page being initialized.  The root of a
+** BTree has no parent and so for that page, pParent==NULL.
+**
+** Return SQLITE_OK on success.  If we see that the page does
+** not contain a well-formed database page, then return 
+** SQLITE_CORRUPT.  Note that a return of SQLITE_OK does not
+** guarantee that the page is well-formed.  It only shows that
+** we failed to detect any corruption.
+*/
+SQLITE_PRIVATE int sqlite3BtreeInitPage(
+  MemPage *pPage,        /* The page to be initialized */
+  MemPage *pParent       /* The parent.  Might be NULL */
+){
+  int pc;            /* Address of a freeblock within pPage->aData[] */
+  int hdr;           /* Offset to beginning of page header */
+  u8 *data;          /* Equal to pPage->aData */
+  BtShared *pBt;        /* The main btree structure */
+  int usableSize;    /* Amount of usable space on each page */
+  int cellOffset;    /* Offset from start of page to first cell pointer */
+  int nFree;         /* Number of unused bytes on the page */
+  int top;           /* First byte of the cell content area */
+
+  pBt = pPage->pBt;
+  assert( pBt!=0 );
+  assert( pParent==0 || pParent->pBt==pBt );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+  assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
+  assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
+  if( pPage->pParent!=pParent && (pPage->pParent!=0 || pPage->isInit) ){
+    /* The parent page should never change unless the file is corrupt */
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( pPage->isInit ) return SQLITE_OK;
+  if( pPage->pParent==0 && pParent!=0 ){
+    pPage->pParent = pParent;
+    sqlite3PagerRef(pParent->pDbPage);
+  }
+  hdr = pPage->hdrOffset;
+  data = pPage->aData;
+  decodeFlags(pPage, data[hdr]);
+  pPage->nOverflow = 0;
+  pPage->idxShift = 0;
+  usableSize = pBt->usableSize;
+  pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
+  top = get2byte(&data[hdr+5]);
+  pPage->nCell = get2byte(&data[hdr+3]);
+  if( pPage->nCell>MX_CELL(pBt) ){
+    /* To many cells for a single page.  The page must be corrupt */
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( pPage->nCell==0 && pParent!=0 && pParent->pgno!=1 ){
+    /* All pages must have at least one cell, except for root pages */
+    return SQLITE_CORRUPT_BKPT;
+  }
+
+  /* Compute the total free space on the page */
+  pc = get2byte(&data[hdr+1]);
+  nFree = data[hdr+7] + top - (cellOffset + 2*pPage->nCell);
+  while( pc>0 ){
+    int next, size;
+    if( pc>usableSize-4 ){
+      /* Free block is off the page */
+      return SQLITE_CORRUPT_BKPT; 
+    }
+    next = get2byte(&data[pc]);
+    size = get2byte(&data[pc+2]);
+    if( next>0 && next<=pc+size+3 ){
+      /* Free blocks must be in accending order */
+      return SQLITE_CORRUPT_BKPT; 
+    }
+    nFree += size;
+    pc = next;
+  }
+  pPage->nFree = nFree;
+  if( nFree>=usableSize ){
+    /* Free space cannot exceed total page size */
+    return SQLITE_CORRUPT_BKPT; 
+  }
+
+  pPage->isInit = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Set up a raw page so that it looks like a database page holding
+** no entries.
+*/
+static void zeroPage(MemPage *pPage, int flags){
+  unsigned char *data = pPage->aData;
+  BtShared *pBt = pPage->pBt;
+  int hdr = pPage->hdrOffset;
+  int first;
+
+  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  memset(&data[hdr], 0, pBt->usableSize - hdr);
+  data[hdr] = flags;
+  first = hdr + 8 + 4*((flags&PTF_LEAF)==0);
+  memset(&data[hdr+1], 0, 4);
+  data[hdr+7] = 0;
+  put2byte(&data[hdr+5], pBt->usableSize);
+  pPage->nFree = pBt->usableSize - first;
+  decodeFlags(pPage, flags);
+  pPage->hdrOffset = hdr;
+  pPage->cellOffset = first;
+  pPage->nOverflow = 0;
+  pPage->idxShift = 0;
+  pPage->nCell = 0;
+  pPage->isInit = 1;
+}
+
+/*
+** Get a page from the pager.  Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.
+**
+** If the noContent flag is set, it means that we do not care about
+** the content of the page at this time.  So do not go to the disk
+** to fetch the content.  Just fill in the content with zeros for now.
+** If in the future we call sqlite3PagerWrite() on this page, that
+** means we have started to be concerned about content and the disk
+** read should occur at that point.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetPage(
+  BtShared *pBt,       /* The btree */
+  Pgno pgno,           /* Number of the page to fetch */
+  MemPage **ppPage,    /* Return the page in this parameter */
+  int noContent        /* Do not load page content if true */
+){
+  int rc;
+  MemPage *pPage;
+  DbPage *pDbPage;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, noContent);
+  if( rc ) return rc;
+  pPage = (MemPage *)sqlite3PagerGetExtra(pDbPage);
+  pPage->aData = sqlite3PagerGetData(pDbPage);
+  pPage->pDbPage = pDbPage;
+  pPage->pBt = pBt;
+  pPage->pgno = pgno;
+  pPage->hdrOffset = pPage->pgno==1 ? 100 : 0;
+  *ppPage = pPage;
+  return SQLITE_OK;
+}
+
+/*
+** Get a page from the pager and initialize it.  This routine
+** is just a convenience wrapper around separate calls to
+** sqlite3BtreeGetPage() and sqlite3BtreeInitPage().
+*/
+static int getAndInitPage(
+  BtShared *pBt,          /* The database file */
+  Pgno pgno,           /* Number of the page to get */
+  MemPage **ppPage,    /* Write the page pointer here */
+  MemPage *pParent     /* Parent of the page */
+){
+  int rc;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno==0 ){
+    return SQLITE_CORRUPT_BKPT; 
+  }
+  rc = sqlite3BtreeGetPage(pBt, pgno, ppPage, 0);
+  if( rc==SQLITE_OK && (*ppPage)->isInit==0 ){
+    rc = sqlite3BtreeInitPage(*ppPage, pParent);
+    if( rc!=SQLITE_OK ){
+      releasePage(*ppPage);
+      *ppPage = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Release a MemPage.  This should be called once for each prior
+** call to sqlite3BtreeGetPage.
+*/
+static void releasePage(MemPage *pPage){
+  if( pPage ){
+    assert( pPage->aData );
+    assert( pPage->pBt );
+    assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+    assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
+    assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+    sqlite3PagerUnref(pPage->pDbPage);
+  }
+}
+
+/*
+** This routine is called when the reference count for a page
+** reaches zero.  We need to unref the pParent pointer when that
+** happens.
+*/
+static void pageDestructor(DbPage *pData, int pageSize){
+  MemPage *pPage;
+  assert( (pageSize & 7)==0 );
+  pPage = (MemPage *)sqlite3PagerGetExtra(pData);
+  assert( pPage->isInit==0 || sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( pPage->pParent ){
+    MemPage *pParent = pPage->pParent;
+    assert( pParent->pBt==pPage->pBt );
+    pPage->pParent = 0;
+    releasePage(pParent);
+  }
+  pPage->isInit = 0;
+}
+
+/*
+** During a rollback, when the pager reloads information into the cache
+** so that the cache is restored to its original state at the start of
+** the transaction, for each page restored this routine is called.
+**
+** This routine needs to reset the extra data section at the end of the
+** page to agree with the restored data.
+*/
+static void pageReinit(DbPage *pData, int pageSize){
+  MemPage *pPage;
+  assert( (pageSize & 7)==0 );
+  pPage = (MemPage *)sqlite3PagerGetExtra(pData);
+  if( pPage->isInit ){
+    assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+    pPage->isInit = 0;
+    sqlite3BtreeInitPage(pPage, pPage->pParent);
+  }
+}
+
+/*
+** Invoke the busy handler for a btree.
+*/
+static int sqlite3BtreeInvokeBusyHandler(void *pArg, int n){
+  BtShared *pBt = (BtShared*)pArg;
+  assert( pBt->db );
+  assert( sqlite3_mutex_held(pBt->db->mutex) );
+  return sqlite3InvokeBusyHandler(&pBt->db->busyHandler);
+}
+
+/*
+** Open a database file.
+** 
+** zFilename is the name of the database file.  If zFilename is NULL
+** a new database with a random name is created.  This randomly named
+** database file will be deleted when sqlite3BtreeClose() is called.
+** If zFilename is ":memory:" then an in-memory database is created
+** that is automatically destroyed when it is closed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  const char *zFilename,  /* Name of the file containing the BTree database */
+  sqlite3 *db,            /* Associated database handle */
+  Btree **ppBtree,        /* Pointer to new Btree object written here */
+  int flags,              /* Options */
+  int vfsFlags            /* Flags passed through to sqlite3_vfs.xOpen() */
+){
+  sqlite3_vfs *pVfs;      /* The VFS to use for this btree */
+  BtShared *pBt = 0;      /* Shared part of btree structure */
+  Btree *p;               /* Handle to return */
+  int rc = SQLITE_OK;
+  int nReserve;
+  unsigned char zDbHeader[100];
+
+  /* Set the variable isMemdb to true for an in-memory database, or 
+  ** false for a file-based database. This symbol is only required if
+  ** either of the shared-data or autovacuum features are compiled 
+  ** into the library.
+  */
+#if !defined(SQLITE_OMIT_SHARED_CACHE) || !defined(SQLITE_OMIT_AUTOVACUUM)
+  #ifdef SQLITE_OMIT_MEMORYDB
+    const int isMemdb = 0;
+  #else
+    const int isMemdb = zFilename && !strcmp(zFilename, ":memory:");
+  #endif
+#endif
+
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  pVfs = db->pVfs;
+  p = sqlite3MallocZero(sizeof(Btree));
+  if( !p ){
+    return SQLITE_NOMEM;
+  }
+  p->inTrans = TRANS_NONE;
+  p->db = db;
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /*
+  ** If this Btree is a candidate for shared cache, try to find an
+  ** existing BtShared object that we can share with
+  */
+  if( (flags & BTREE_PRIVATE)==0
+   && isMemdb==0
+   && (db->flags & SQLITE_Vtab)==0
+   && zFilename && zFilename[0]
+  ){
+    if( sqlite3SharedCacheEnabled ){
+      int nFullPathname = pVfs->mxPathname+1;
+      char *zFullPathname = (char *)sqlite3_malloc(nFullPathname);
+      sqlite3_mutex *mutexShared;
+      p->sharable = 1;
+      if( db ){
+        db->flags |= SQLITE_SharedCache;
+      }
+      if( !zFullPathname ){
+        sqlite3_free(p);
+        return SQLITE_NOMEM;
+      }
+      sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
+      mutexShared = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+      sqlite3_mutex_enter(mutexShared);
+      for(pBt=sqlite3SharedCacheList; pBt; pBt=pBt->pNext){
+        assert( pBt->nRef>0 );
+        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager))
+                 && sqlite3PagerVfs(pBt->pPager)==pVfs ){
+          p->pBt = pBt;
+          pBt->nRef++;
+          break;
+        }
+      }
+      sqlite3_mutex_leave(mutexShared);
+      sqlite3_free(zFullPathname);
+    }
+#ifdef SQLITE_DEBUG
+    else{
+      /* In debug mode, we mark all persistent databases as sharable
+      ** even when they are not.  This exercises the locking code and
+      ** gives more opportunity for asserts(sqlite3_mutex_held())
+      ** statements to find locking problems.
+      */
+      p->sharable = 1;
+    }
+#endif
+  }
+#endif
+  if( pBt==0 ){
+    /*
+    ** The following asserts make sure that structures used by the btree are
+    ** the right size.  This is to guard against size changes that result
+    ** when compiling on a different architecture.
+    */
+    assert( sizeof(i64)==8 || sizeof(i64)==4 );
+    assert( sizeof(u64)==8 || sizeof(u64)==4 );
+    assert( sizeof(u32)==4 );
+    assert( sizeof(u16)==2 );
+    assert( sizeof(Pgno)==4 );
+  
+    pBt = sqlite3MallocZero( sizeof(*pBt) );
+    if( pBt==0 ){
+      rc = SQLITE_NOMEM;
+      goto btree_open_out;
+    }
+    pBt->busyHdr.xFunc = sqlite3BtreeInvokeBusyHandler;
+    pBt->busyHdr.pArg = pBt;
+    rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
+                          EXTRA_SIZE, flags, vfsFlags);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
+    }
+    if( rc!=SQLITE_OK ){
+      goto btree_open_out;
+    }
+    sqlite3PagerSetBusyhandler(pBt->pPager, &pBt->busyHdr);
+    p->pBt = pBt;
+  
+    sqlite3PagerSetDestructor(pBt->pPager, pageDestructor);
+    sqlite3PagerSetReiniter(pBt->pPager, pageReinit);
+    pBt->pCursor = 0;
+    pBt->pPage1 = 0;
+    pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
+    pBt->pageSize = get2byte(&zDbHeader[16]);
+    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
+         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
+      pBt->pageSize = 0;
+      sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
+      pBt->maxEmbedFrac = 64;   /* 25% */
+      pBt->minEmbedFrac = 32;   /* 12.5% */
+      pBt->minLeafFrac = 32;    /* 12.5% */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the magic name ":memory:" will create an in-memory database, then
+      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
+      ** SQLITE_DEFAULT_AUTOVACUUM is true. On the other hand, if
+      ** SQLITE_OMIT_MEMORYDB has been defined, then ":memory:" is just a
+      ** regular file-name. In this case the auto-vacuum applies as per normal.
+      */
+      if( zFilename && !isMemdb ){
+        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
+        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
+      }
+#endif
+      nReserve = 0;
+    }else{
+      nReserve = zDbHeader[20];
+      pBt->maxEmbedFrac = zDbHeader[21];
+      pBt->minEmbedFrac = zDbHeader[22];
+      pBt->minLeafFrac = zDbHeader[23];
+      pBt->pageSizeFixed = 1;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
+      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
+#endif
+    }
+    pBt->usableSize = pBt->pageSize - nReserve;
+    assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
+    sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
+   
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+    /* Add the new BtShared object to the linked list sharable BtShareds.
+    */
+    if( p->sharable ){
+      sqlite3_mutex *mutexShared;
+      pBt->nRef = 1;
+      mutexShared = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+      if( SQLITE_THREADSAFE ){
+        pBt->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+        if( pBt->mutex==0 ){
+          rc = SQLITE_NOMEM;
+          db->mallocFailed = 0;
+          goto btree_open_out;
+        }
+      }
+      sqlite3_mutex_enter(mutexShared);
+      pBt->pNext = sqlite3SharedCacheList;
+      sqlite3SharedCacheList = pBt;
+      sqlite3_mutex_leave(mutexShared);
+    }
+#endif
+  }
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /* If the new Btree uses a sharable pBtShared, then link the new
+  ** Btree into the list of all sharable Btrees for the same connection.
+  ** The list is kept in ascending order by pBt address.
+  */
+  if( p->sharable ){
+    int i;
+    Btree *pSib;
+    for(i=0; i<db->nDb; i++){
+      if( (pSib = db->aDb[i].pBt)!=0 && pSib->sharable ){
+        while( pSib->pPrev ){ pSib = pSib->pPrev; }
+        if( p->pBt<pSib->pBt ){
+          p->pNext = pSib;
+          p->pPrev = 0;
+          pSib->pPrev = p;
+        }else{
+          while( pSib->pNext && pSib->pNext->pBt<p->pBt ){
+            pSib = pSib->pNext;
+          }
+          p->pNext = pSib->pNext;
+          p->pPrev = pSib;
+          if( p->pNext ){
+            p->pNext->pPrev = p;
+          }
+          pSib->pNext = p;
+        }
+        break;
+      }
+    }
+  }
+#endif
+  *ppBtree = p;
+
+btree_open_out:
+  if( rc!=SQLITE_OK ){
+    if( pBt && pBt->pPager ){
+      sqlite3PagerClose(pBt->pPager);
+    }
+    sqlite3_free(pBt);
+    sqlite3_free(p);
+    *ppBtree = 0;
+  }
+  return rc;
+}
+
+/*
+** Decrement the BtShared.nRef counter.  When it reaches zero,
+** remove the BtShared structure from the sharing list.  Return
+** true if the BtShared.nRef counter reaches zero and return
+** false if it is still positive.
+*/
+static int removeFromSharingList(BtShared *pBt){
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  sqlite3_mutex *pMaster;
+  BtShared *pList;
+  int removed = 0;
+
+  assert( sqlite3_mutex_notheld(pBt->mutex) );
+  pMaster = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+  sqlite3_mutex_enter(pMaster);
+  pBt->nRef--;
+  if( pBt->nRef<=0 ){
+    if( sqlite3SharedCacheList==pBt ){
+      sqlite3SharedCacheList = pBt->pNext;
+    }else{
+      pList = sqlite3SharedCacheList;
+      while( pList && pList->pNext!=pBt ){
+        pList=pList->pNext;
+      }
+      if( pList ){
+        pList->pNext = pBt->pNext;
+      }
+    }
+    if( SQLITE_THREADSAFE ){
+      sqlite3_mutex_free(pBt->mutex);
+    }
+    removed = 1;
+  }
+  sqlite3_mutex_leave(pMaster);
+  return removed;
+#else
+  return 1;
+#endif
+}
+
+/*
+** Close an open database and invalidate all cursors.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
+  BtShared *pBt = p->pBt;
+  BtCursor *pCur;
+
+  /* Close all cursors opened via this handle.  */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  pCur = pBt->pCursor;
+  while( pCur ){
+    BtCursor *pTmp = pCur;
+    pCur = pCur->pNext;
+    if( pTmp->pBtree==p ){
+      sqlite3BtreeCloseCursor(pTmp);
+    }
+  }
+
+  /* Rollback any active transaction and free the handle structure.
+  ** The call to sqlite3BtreeRollback() drops any table-locks held by
+  ** this handle.
+  */
+  sqlite3BtreeRollback(p);
+  sqlite3BtreeLeave(p);
+
+  /* If there are still other outstanding references to the shared-btree
+  ** structure, return now. The remainder of this procedure cleans 
+  ** up the shared-btree.
+  */
+  assert( p->wantToLock==0 && p->locked==0 );
+  if( !p->sharable || removeFromSharingList(pBt) ){
+    /* The pBt is no longer on the sharing list, so we can access
+    ** it without having to hold the mutex.
+    **
+    ** Clean out and delete the BtShared object.
+    */
+    assert( !pBt->pCursor );
+    sqlite3PagerClose(pBt->pPager);
+    if( pBt->xFreeSchema && pBt->pSchema ){
+      pBt->xFreeSchema(pBt->pSchema);
+    }
+    sqlite3_free(pBt->pSchema);
+    sqlite3_free(pBt->pTmpSpace);
+    sqlite3_free(pBt);
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  assert( p->wantToLock==0 );
+  assert( p->locked==0 );
+  if( p->pPrev ) p->pPrev->pNext = p->pNext;
+  if( p->pNext ) p->pNext->pPrev = p->pPrev;
+#endif
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the limit on the number of pages allowed in the cache.
+**
+** The maximum number of cache pages is set to the absolute
+** value of mxPage.  If mxPage is negative, the pager will
+** operate asynchronously - it will not stop to do fsync()s
+** to insure data is written to the disk surface before
+** continuing.  Transactions still work if synchronous is off,
+** and the database cannot be corrupted if this program
+** crashes.  But if the operating system crashes or there is
+** an abrupt power failure when synchronous is off, the database
+** could be left in an inconsistent and unrecoverable state.
+** Synchronous is on by default so database corruption is not
+** normally a worry.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetCachesize(pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the way data is synced to disk in order to increase or decrease
+** how well the database resists damage due to OS crashes and power
+** failures.  Level 1 is the same as asynchronous (no syncs() occur and
+** there is a high probability of damage)  Level 2 is the default.  There
+** is a very low but non-zero probability of damage.  Level 3 reduces the
+** probability of damage to near zero but with a write performance reduction.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree *p, int level, int fullSync){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Return TRUE if the given btree is set to safety level 1.  In other
+** words, return TRUE if no sync() occurs on the disk files.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree *p){
+  BtShared *pBt = p->pBt;
+  int rc;
+  assert( sqlite3_mutex_held(p->db->mutex) );  
+  sqlite3BtreeEnter(p);
+  assert( pBt && pBt->pPager );
+  rc = sqlite3PagerNosync(pBt->pPager);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM)
+/*
+** Change the default pages size and the number of reserved bytes per page.
+**
+** The page size must be a power of 2 between 512 and 65536.  If the page
+** size supplied does not meet this constraint then the page size is not
+** changed.
+**
+** Page sizes are constrained to be a power of two so that the region
+** of the database file used for locking (beginning at PENDING_BYTE,
+** the first byte past the 1GB boundary, 0x40000000) needs to occur
+** at the beginning of a page.
+**
+** If parameter nReserve is less than zero, then the number of reserved
+** bytes per page is left unchanged.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve){
+  int rc = SQLITE_OK;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  if( pBt->pageSizeFixed ){
+    sqlite3BtreeLeave(p);
+    return SQLITE_READONLY;
+  }
+  if( nReserve<0 ){
+    nReserve = pBt->pageSize - pBt->usableSize;
+  }
+  if( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE &&
+        ((pageSize-1)&pageSize)==0 ){
+    assert( (pageSize & 7)==0 );
+    assert( !pBt->pPage1 && !pBt->pCursor );
+    pBt->pageSize = pageSize;
+    sqlite3_free(pBt->pTmpSpace);
+    pBt->pTmpSpace = 0;
+    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
+  }
+  pBt->usableSize = pBt->pageSize - nReserve;
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Return the currently defined page size
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree *p){
+  return p->pBt->pageSize;
+}
+SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree *p){
+  int n;
+  sqlite3BtreeEnter(p);
+  n = p->pBt->pageSize - p->pBt->usableSize;
+  sqlite3BtreeLeave(p);
+  return n;
+}
+
+/*
+** Set the maximum page count for a database if mxPage is positive.
+** No changes are made if mxPage is 0 or negative.
+** Regardless of the value of mxPage, return the maximum page count.
+*/
+SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree *p, int mxPage){
+  int n;
+  sqlite3BtreeEnter(p);
+  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return n;
+}
+#endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */
+
+/*
+** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
+** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
+** is disabled. The default value for the auto-vacuum property is 
+** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return SQLITE_READONLY;
+#else
+  BtShared *pBt = p->pBt;
+  int rc = SQLITE_OK;
+  int av = (autoVacuum?1:0);
+
+  sqlite3BtreeEnter(p);
+  if( pBt->pageSizeFixed && av!=pBt->autoVacuum ){
+    rc = SQLITE_READONLY;
+  }else{
+    pBt->autoVacuum = av;
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+/*
+** Return the value of the 'auto-vacuum' property. If auto-vacuum is 
+** enabled 1 is returned. Otherwise 0.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *p){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return BTREE_AUTOVACUUM_NONE;
+#else
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = (
+    (!p->pBt->autoVacuum)?BTREE_AUTOVACUUM_NONE:
+    (!p->pBt->incrVacuum)?BTREE_AUTOVACUUM_FULL:
+    BTREE_AUTOVACUUM_INCR
+  );
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+
+/*
+** Get a reference to pPage1 of the database file.  This will
+** also acquire a readlock on that file.
+**
+** SQLITE_OK is returned on success.  If the file is not a
+** well-formed database file, then SQLITE_CORRUPT is returned.
+** SQLITE_BUSY is returned if the database is locked.  SQLITE_NOMEM
+** is returned if we run out of memory. 
+*/
+static int lockBtree(BtShared *pBt){
+  int rc;
+  MemPage *pPage1;
+  int nPage;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->pPage1 ) return SQLITE_OK;
+  rc = sqlite3BtreeGetPage(pBt, 1, &pPage1, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Do some checking to help insure the file we opened really is
+  ** a valid database file. 
+  */
+  rc = SQLITE_NOTADB;
+  nPage = sqlite3PagerPagecount(pBt->pPager);
+  if( nPage<0 ){
+    rc = SQLITE_IOERR;
+    goto page1_init_failed;
+  }else if( nPage>0 ){
+    int pageSize;
+    int usableSize;
+    u8 *page1 = pPage1->aData;
+    if( memcmp(page1, zMagicHeader, 16)!=0 ){
+      goto page1_init_failed;
+    }
+    if( page1[18]>1 ){
+      pBt->readOnly = 1;
+    }
+    if( page1[19]>1 ){
+      goto page1_init_failed;
+    }
+    pageSize = get2byte(&page1[16]);
+    if( ((pageSize-1)&pageSize)!=0 || pageSize<512 ||
+        (SQLITE_MAX_PAGE_SIZE<32768 && pageSize>SQLITE_MAX_PAGE_SIZE)
+    ){
+      goto page1_init_failed;
+    }
+    assert( (pageSize & 7)==0 );
+    usableSize = pageSize - page1[20];
+    if( pageSize!=pBt->pageSize ){
+      /* After reading the first page of the database assuming a page size
+      ** of BtShared.pageSize, we have discovered that the page-size is
+      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
+      ** zero and return SQLITE_OK. The caller will call this function
+      ** again with the correct page-size.
+      */
+      releasePage(pPage1);
+      pBt->usableSize = usableSize;
+      pBt->pageSize = pageSize;
+      sqlite3_free(pBt->pTmpSpace);
+      pBt->pTmpSpace = 0;
+      sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
+      return SQLITE_OK;
+    }
+    if( usableSize<500 ){
+      goto page1_init_failed;
+    }
+    pBt->pageSize = pageSize;
+    pBt->usableSize = usableSize;
+    pBt->maxEmbedFrac = page1[21];
+    pBt->minEmbedFrac = page1[22];
+    pBt->minLeafFrac = page1[23];
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
+    pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
+#endif
+  }
+
+  /* maxLocal is the maximum amount of payload to store locally for
+  ** a cell.  Make sure it is small enough so that at least minFanout
+  ** cells can will fit on one page.  We assume a 10-byte page header.
+  ** Besides the payload, the cell must store:
+  **     2-byte pointer to the cell
+  **     4-byte child pointer
+  **     9-byte nKey value
+  **     4-byte nData value
+  **     4-byte overflow page pointer
+  ** So a cell consists of a 2-byte poiner, a header which is as much as
+  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
+  ** page pointer.
+  */
+  pBt->maxLocal = (pBt->usableSize-12)*pBt->maxEmbedFrac/255 - 23;
+  pBt->minLocal = (pBt->usableSize-12)*pBt->minEmbedFrac/255 - 23;
+  pBt->maxLeaf = pBt->usableSize - 35;
+  pBt->minLeaf = (pBt->usableSize-12)*pBt->minLeafFrac/255 - 23;
+  if( pBt->minLocal>pBt->maxLocal || pBt->maxLocal<0 ){
+    goto page1_init_failed;
+  }
+  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
+  pBt->pPage1 = pPage1;
+  return SQLITE_OK;
+
+page1_init_failed:
+  releasePage(pPage1);
+  pBt->pPage1 = 0;
+  return rc;
+}
+
+/*
+** This routine works like lockBtree() except that it also invokes the
+** busy callback if there is lock contention.
+*/
+static int lockBtreeWithRetry(Btree *pRef){
+  int rc = SQLITE_OK;
+
+  assert( sqlite3BtreeHoldsMutex(pRef) );
+  if( pRef->inTrans==TRANS_NONE ){
+    u8 inTransaction = pRef->pBt->inTransaction;
+    btreeIntegrity(pRef);
+    rc = sqlite3BtreeBeginTrans(pRef, 0);
+    pRef->pBt->inTransaction = inTransaction;
+    pRef->inTrans = TRANS_NONE;
+    if( rc==SQLITE_OK ){
+      pRef->pBt->nTransaction--;
+    }
+    btreeIntegrity(pRef);
+  }
+  return rc;
+}
+       
+
+/*
+** If there are no outstanding cursors and we are not in the middle
+** of a transaction but there is a read lock on the database, then
+** this routine unrefs the first page of the database file which 
+** has the effect of releasing the read lock.
+**
+** If there are any outstanding cursors, this routine is a no-op.
+**
+** If there is a transaction in progress, this routine is a no-op.
+*/
+static void unlockBtreeIfUnused(BtShared *pBt){
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->inTransaction==TRANS_NONE && pBt->pCursor==0 && pBt->pPage1!=0 ){
+    if( sqlite3PagerRefcount(pBt->pPager)>=1 ){
+      assert( pBt->pPage1->aData );
+#if 0
+      if( pBt->pPage1->aData==0 ){
+        MemPage *pPage = pBt->pPage1;
+        pPage->aData = sqlite3PagerGetData(pPage->pDbPage);
+        pPage->pBt = pBt;
+        pPage->pgno = 1;
+      }
+#endif
+      releasePage(pBt->pPage1);
+    }
+    pBt->pPage1 = 0;
+    pBt->inStmt = 0;
+  }
+}
+
+/*
+** Create a new database by initializing the first page of the
+** file.
+*/
+static int newDatabase(BtShared *pBt){
+  MemPage *pP1;
+  unsigned char *data;
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( sqlite3PagerPagecount(pBt->pPager)>0 ) return SQLITE_OK;
+  pP1 = pBt->pPage1;
+  assert( pP1!=0 );
+  data = pP1->aData;
+  rc = sqlite3PagerWrite(pP1->pDbPage);
+  if( rc ) return rc;
+  memcpy(data, zMagicHeader, sizeof(zMagicHeader));
+  assert( sizeof(zMagicHeader)==16 );
+  put2byte(&data[16], pBt->pageSize);
+  data[18] = 1;
+  data[19] = 1;
+  data[20] = pBt->pageSize - pBt->usableSize;
+  data[21] = pBt->maxEmbedFrac;
+  data[22] = pBt->minEmbedFrac;
+  data[23] = pBt->minLeafFrac;
+  memset(&data[24], 0, 100-24);
+  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
+  pBt->pageSizeFixed = 1;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
+  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
+  put4byte(&data[36 + 4*4], pBt->autoVacuum);
+  put4byte(&data[36 + 7*4], pBt->incrVacuum);
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Attempt to start a new transaction. A write-transaction
+** is started if the second argument is nonzero, otherwise a read-
+** transaction.  If the second argument is 2 or more and exclusive
+** transaction is started, meaning that no other process is allowed
+** to access the database.  A preexisting transaction may not be
+** upgraded to exclusive by calling this routine a second time - the
+** exclusivity flag only works for a new transaction.
+**
+** A write-transaction must be started before attempting any 
+** changes to the database.  None of the following routines 
+** will work unless a transaction is started first:
+**
+**      sqlite3BtreeCreateTable()
+**      sqlite3BtreeCreateIndex()
+**      sqlite3BtreeClearTable()
+**      sqlite3BtreeDropTable()
+**      sqlite3BtreeInsert()
+**      sqlite3BtreeDelete()
+**      sqlite3BtreeUpdateMeta()
+**
+** If an initial attempt to acquire the lock fails because of lock contention
+** and the database was previously unlocked, then invoke the busy handler
+** if there is one.  But if there was previously a read-lock, do not
+** invoke the busy handler - just return SQLITE_BUSY.  SQLITE_BUSY is 
+** returned when there is already a read-lock in order to avoid a deadlock.
+**
+** Suppose there are two processes A and B.  A has a read lock and B has
+** a reserved lock.  B tries to promote to exclusive but is blocked because
+** of A's read lock.  A tries to promote to reserved but is blocked by B.
+** One or the other of the two processes must give way or there can be
+** no progress.  By returning SQLITE_BUSY and not invoking the busy callback
+** when A already has a read lock, we encourage A to give up and let B
+** proceed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
+  BtShared *pBt = p->pBt;
+  int rc = SQLITE_OK;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  btreeIntegrity(p);
+
+  /* If the btree is already in a write-transaction, or it
+  ** is already in a read-transaction and a read-transaction
+  ** is requested, this is a no-op.
+  */
+  if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
+    goto trans_begun;
+  }
+
+  /* Write transactions are not possible on a read-only database */
+  if( pBt->readOnly && wrflag ){
+    rc = SQLITE_READONLY;
+    goto trans_begun;
+  }
+
+  /* If another database handle has already opened a write transaction 
+  ** on this shared-btree structure and a second write transaction is
+  ** requested, return SQLITE_BUSY.
+  */
+  if( pBt->inTransaction==TRANS_WRITE && wrflag ){
+    rc = SQLITE_BUSY;
+    goto trans_begun;
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  if( wrflag>1 ){
+    BtLock *pIter;
+    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+      if( pIter->pBtree!=p ){
+        rc = SQLITE_BUSY;
+        goto trans_begun;
+      }
+    }
+  }
+#endif
+
+  do {
+    if( pBt->pPage1==0 ){
+      do{
+        rc = lockBtree(pBt);
+      }while( pBt->pPage1==0 && rc==SQLITE_OK );
+    }
+
+    if( rc==SQLITE_OK && wrflag ){
+      if( pBt->readOnly ){
+        rc = SQLITE_READONLY;
+      }else{
+        rc = sqlite3PagerBegin(pBt->pPage1->pDbPage, wrflag>1);
+        if( rc==SQLITE_OK ){
+          rc = newDatabase(pBt);
+        }
+      }
+    }
+  
+    if( rc==SQLITE_OK ){
+      if( wrflag ) pBt->inStmt = 0;
+    }else{
+      unlockBtreeIfUnused(pBt);
+    }
+  }while( rc==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
+          sqlite3BtreeInvokeBusyHandler(pBt, 0) );
+
+  if( rc==SQLITE_OK ){
+    if( p->inTrans==TRANS_NONE ){
+      pBt->nTransaction++;
+    }
+    p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);
+    if( p->inTrans>pBt->inTransaction ){
+      pBt->inTransaction = p->inTrans;
+    }
+#ifndef SQLITE_OMIT_SHARED_CACHE
+    if( wrflag>1 ){
+      assert( !pBt->pExclusive );
+      pBt->pExclusive = p;
+    }
+#endif
+  }
+
+
+trans_begun:
+  btreeIntegrity(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+
+/*
+** Set the pointer-map entries for all children of page pPage. Also, if
+** pPage contains cells that point to overflow pages, set the pointer
+** map entries for the overflow pages as well.
+*/
+static int setChildPtrmaps(MemPage *pPage){
+  int i;                             /* Counter variable */
+  int nCell;                         /* Number of cells in page pPage */
+  int rc;                            /* Return code */
+  BtShared *pBt = pPage->pBt;
+  int isInitOrig = pPage->isInit;
+  Pgno pgno = pPage->pgno;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  rc = sqlite3BtreeInitPage(pPage, pPage->pParent);
+  if( rc!=SQLITE_OK ){
+    goto set_child_ptrmaps_out;
+  }
+  nCell = pPage->nCell;
+
+  for(i=0; i<nCell; i++){
+    u8 *pCell = findCell(pPage, i);
+
+    rc = ptrmapPutOvflPtr(pPage, pCell);
+    if( rc!=SQLITE_OK ){
+      goto set_child_ptrmaps_out;
+    }
+
+    if( !pPage->leaf ){
+      Pgno childPgno = get4byte(pCell);
+      rc = ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno);
+      if( rc!=SQLITE_OK ) goto set_child_ptrmaps_out;
+    }
+  }
+
+  if( !pPage->leaf ){
+    Pgno childPgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    rc = ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno);
+  }
+
+set_child_ptrmaps_out:
+  pPage->isInit = isInitOrig;
+  return rc;
+}
+
+/*
+** Somewhere on pPage, which is guarenteed to be a btree page, not an overflow
+** page, is a pointer to page iFrom. Modify this pointer so that it points to
+** iTo. Parameter eType describes the type of pointer to be modified, as 
+** follows:
+**
+** PTRMAP_BTREE:     pPage is a btree-page. The pointer points at a child 
+**                   page of pPage.
+**
+** PTRMAP_OVERFLOW1: pPage is a btree-page. The pointer points at an overflow
+**                   page pointed to by one of the cells on pPage.
+**
+** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
+**                   overflow page in the list.
+*/
+static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( eType==PTRMAP_OVERFLOW2 ){
+    /* The pointer is always the first 4 bytes of the page in this case.  */
+    if( get4byte(pPage->aData)!=iFrom ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+    put4byte(pPage->aData, iTo);
+  }else{
+    int isInitOrig = pPage->isInit;
+    int i;
+    int nCell;
+
+    sqlite3BtreeInitPage(pPage, 0);
+    nCell = pPage->nCell;
+
+    for(i=0; i<nCell; i++){
+      u8 *pCell = findCell(pPage, i);
+      if( eType==PTRMAP_OVERFLOW1 ){
+        CellInfo info;
+        sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+        if( info.iOverflow ){
+          if( iFrom==get4byte(&pCell[info.iOverflow]) ){
+            put4byte(&pCell[info.iOverflow], iTo);
+            break;
+          }
+        }
+      }else{
+        if( get4byte(pCell)==iFrom ){
+          put4byte(pCell, iTo);
+          break;
+        }
+      }
+    }
+  
+    if( i==nCell ){
+      if( eType!=PTRMAP_BTREE || 
+          get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
+        return SQLITE_CORRUPT_BKPT;
+      }
+      put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
+    }
+
+    pPage->isInit = isInitOrig;
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Move the open database page pDbPage to location iFreePage in the 
+** database. The pDbPage reference remains valid.
+*/
+static int relocatePage(
+  BtShared *pBt,           /* Btree */
+  MemPage *pDbPage,        /* Open page to move */
+  u8 eType,                /* Pointer map 'type' entry for pDbPage */
+  Pgno iPtrPage,           /* Pointer map 'page-no' entry for pDbPage */
+  Pgno iFreePage           /* The location to move pDbPage to */
+){
+  MemPage *pPtrPage;   /* The page that contains a pointer to pDbPage */
+  Pgno iDbPage = pDbPage->pgno;
+  Pager *pPager = pBt->pPager;
+  int rc;
+
+  assert( eType==PTRMAP_OVERFLOW2 || eType==PTRMAP_OVERFLOW1 || 
+      eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pDbPage->pBt==pBt );
+
+  /* Move page iDbPage from its current location to page number iFreePage */
+  TRACE(("AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n", 
+      iDbPage, iFreePage, iPtrPage, eType));
+  rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pDbPage->pgno = iFreePage;
+
+  /* If pDbPage was a btree-page, then it may have child pages and/or cells
+  ** that point to overflow pages. The pointer map entries for all these
+  ** pages need to be changed.
+  **
+  ** If pDbPage is an overflow page, then the first 4 bytes may store a
+  ** pointer to a subsequent overflow page. If this is the case, then
+  ** the pointer map needs to be updated for the subsequent overflow page.
+  */
+  if( eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE ){
+    rc = setChildPtrmaps(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }else{
+    Pgno nextOvfl = get4byte(pDbPage->aData);
+    if( nextOvfl!=0 ){
+      rc = ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  /* Fix the database pointer on page iPtrPage that pointed at iDbPage so
+  ** that it points at iFreePage. Also fix the pointer map entry for
+  ** iPtrPage.
+  */
+  if( eType!=PTRMAP_ROOTPAGE ){
+    rc = sqlite3BtreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    rc = sqlite3PagerWrite(pPtrPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(pPtrPage);
+      return rc;
+    }
+    rc = modifyPagePointer(pPtrPage, iDbPage, iFreePage, eType);
+    releasePage(pPtrPage);
+    if( rc==SQLITE_OK ){
+      rc = ptrmapPut(pBt, iFreePage, eType, iPtrPage);
+    }
+  }
+  return rc;
+}
+
+/* Forward declaration required by incrVacuumStep(). */
+static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
+
+/*
+** Perform a single step of an incremental-vacuum. If successful,
+** return SQLITE_OK. If there is no work to do (and therefore no
+** point in calling this function again), return SQLITE_DONE.
+**
+** More specificly, this function attempts to re-organize the 
+** database so that the last page of the file currently in use
+** is no longer in use.
+**
+** If the nFin parameter is non-zero, the implementation assumes
+** that the caller will keep calling incrVacuumStep() until
+** it returns SQLITE_DONE or an error, and that nFin is the
+** number of pages the database file will contain after this 
+** process is complete.
+*/
+static int incrVacuumStep(BtShared *pBt, Pgno nFin){
+  Pgno iLastPg;             /* Last page in the database */
+  Pgno nFreeList;           /* Number of pages still on the free-list */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  iLastPg = pBt->nTrunc;
+  if( iLastPg==0 ){
+    iLastPg = sqlite3PagerPagecount(pBt->pPager);
+  }
+
+  if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
+    int rc;
+    u8 eType;
+    Pgno iPtrPage;
+
+    nFreeList = get4byte(&pBt->pPage1->aData[36]);
+    if( nFreeList==0 || nFin==iLastPg ){
+      return SQLITE_DONE;
+    }
+
+    rc = ptrmapGet(pBt, iLastPg, &eType, &iPtrPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( eType==PTRMAP_ROOTPAGE ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    if( eType==PTRMAP_FREEPAGE ){
+      if( nFin==0 ){
+        /* Remove the page from the files free-list. This is not required
+        ** if nFin is non-zero. In that case, the free-list will be
+        ** truncated to zero after this function returns, so it doesn't 
+        ** matter if it still contains some garbage entries.
+        */
+        Pgno iFreePg;
+        MemPage *pFreePg;
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iLastPg, 1);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        assert( iFreePg==iLastPg );
+        releasePage(pFreePg);
+      }
+    } else {
+      Pgno iFreePg;             /* Index of free page to move pLastPg to */
+      MemPage *pLastPg;
+
+      rc = sqlite3BtreeGetPage(pBt, iLastPg, &pLastPg, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+
+      /* If nFin is zero, this loop runs exactly once and page pLastPg
+      ** is swapped with the first free page pulled off the free list.
+      **
+      ** On the other hand, if nFin is greater than zero, then keep
+      ** looping until a free-page located within the first nFin pages
+      ** of the file is found.
+      */
+      do {
+        MemPage *pFreePg;
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, 0, 0);
+        if( rc!=SQLITE_OK ){
+          releasePage(pLastPg);
+          return rc;
+        }
+        releasePage(pFreePg);
+      }while( nFin!=0 && iFreePg>nFin );
+      assert( iFreePg<iLastPg );
+      
+      rc = sqlite3PagerWrite(pLastPg->pDbPage);
+      if( rc==SQLITE_OK ){
+        rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg);
+      }
+      releasePage(pLastPg);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  pBt->nTrunc = iLastPg - 1;
+  while( pBt->nTrunc==PENDING_BYTE_PAGE(pBt)||PTRMAP_ISPAGE(pBt, pBt->nTrunc) ){
+    pBt->nTrunc--;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** A write-transaction must be opened before calling this function.
+** It performs a single unit of work towards an incremental vacuum.
+**
+** If the incremental vacuum is finished after this function has run,
+** SQLITE_DONE is returned. If it is not finished, but no error occured,
+** SQLITE_OK is returned. Otherwise an SQLite error code. 
+*/
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  assert( pBt->inTransaction==TRANS_WRITE && p->inTrans==TRANS_WRITE );
+  if( !pBt->autoVacuum ){
+    rc = SQLITE_DONE;
+  }else{
+    invalidateAllOverflowCache(pBt);
+    rc = incrVacuumStep(pBt, 0);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** This routine is called prior to sqlite3PagerCommit when a transaction
+** is commited for an auto-vacuum database.
+**
+** If SQLITE_OK is returned, then *pnTrunc is set to the number of pages
+** the database file should be truncated to during the commit process. 
+** i.e. the database has been reorganized so that only the first *pnTrunc
+** pages are in use.
+*/
+static int autoVacuumCommit(BtShared *pBt, Pgno *pnTrunc){
+  int rc = SQLITE_OK;
+  Pager *pPager = pBt->pPager;
+#ifndef NDEBUG
+  int nRef = sqlite3PagerRefcount(pPager);
+#endif
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  invalidateAllOverflowCache(pBt);
+  assert(pBt->autoVacuum);
+  if( !pBt->incrVacuum ){
+    Pgno nFin = 0;
+
+    if( pBt->nTrunc==0 ){
+      Pgno nFree;
+      Pgno nPtrmap;
+      const int pgsz = pBt->pageSize;
+      Pgno nOrig = sqlite3PagerPagecount(pBt->pPager);
+
+      if( PTRMAP_ISPAGE(pBt, nOrig) ){
+        return SQLITE_CORRUPT_BKPT;
+      }
+      if( nOrig==PENDING_BYTE_PAGE(pBt) ){
+        nOrig--;
+      }
+      nFree = get4byte(&pBt->pPage1->aData[36]);
+      nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+pgsz/5)/(pgsz/5);
+      nFin = nOrig - nFree - nPtrmap;
+      if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<=PENDING_BYTE_PAGE(pBt) ){
+        nFin--;
+      }
+      while( PTRMAP_ISPAGE(pBt, nFin) || nFin==PENDING_BYTE_PAGE(pBt) ){
+        nFin--;
+      }
+    }
+
+    while( rc==SQLITE_OK ){
+      rc = incrVacuumStep(pBt, nFin);
+    }
+    if( rc==SQLITE_DONE ){
+      assert(nFin==0 || pBt->nTrunc==0 || nFin<=pBt->nTrunc);
+      rc = SQLITE_OK;
+      if( pBt->nTrunc && nFin ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        put4byte(&pBt->pPage1->aData[32], 0);
+        put4byte(&pBt->pPage1->aData[36], 0);
+        pBt->nTrunc = nFin;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3PagerRollback(pPager);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    *pnTrunc = pBt->nTrunc;
+    pBt->nTrunc = 0;
+  }
+  assert( nRef==sqlite3PagerRefcount(pPager) );
+  return rc;
+}
+
+#endif
+
+/*
+** This routine does the first phase of a two-phase commit.  This routine
+** causes a rollback journal to be created (if it does not already exist)
+** and populated with enough information so that if a power loss occurs
+** the database can be restored to its original state by playing back
+** the journal.  Then the contents of the journal are flushed out to
+** the disk.  After the journal is safely on oxide, the changes to the
+** database are written into the database file and flushed to oxide.
+** At the end of this call, the rollback journal still exists on the
+** disk and we are still holding all locks, so the transaction has not
+** committed.  See sqlite3BtreeCommit() for the second phase of the
+** commit process.
+**
+** This call is a no-op if no write-transaction is currently active on pBt.
+**
+** Otherwise, sync the database file for the btree pBt. zMaster points to
+** the name of a master journal file that should be written into the
+** individual journal file, or is NULL, indicating no master journal file 
+** (single database transaction).
+**
+** When this is called, the master journal should already have been
+** created, populated with this journal pointer and synced to disk.
+**
+** Once this is routine has returned, the only thing required to commit
+** the write-transaction for this database file is to delete the journal.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zMaster){
+  int rc = SQLITE_OK;
+  if( p->inTrans==TRANS_WRITE ){
+    BtShared *pBt = p->pBt;
+    Pgno nTrunc = 0;
+    sqlite3BtreeEnter(p);
+    pBt->db = p->db;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      rc = autoVacuumCommit(pBt, &nTrunc); 
+      if( rc!=SQLITE_OK ){
+        sqlite3BtreeLeave(p);
+        return rc;
+      }
+    }
+#endif
+    rc = sqlite3PagerCommitPhaseOne(pBt->pPager, zMaster, nTrunc, 0);
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+
+/*
+** Commit the transaction currently in progress.
+**
+** This routine implements the second phase of a 2-phase commit.  The
+** sqlite3BtreeSync() routine does the first phase and should be invoked
+** prior to calling this routine.  The sqlite3BtreeSync() routine did
+** all the work of writing information out to disk and flushing the
+** contents so that they are written onto the disk platter.  All this
+** routine has to do is delete or truncate the rollback journal
+** (which causes the transaction to commit) and drop locks.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p){
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  btreeIntegrity(p);
+
+  /* If the handle has a write-transaction open, commit the shared-btrees 
+  ** transaction and set the shared state to TRANS_READ.
+  */
+  if( p->inTrans==TRANS_WRITE ){
+    int rc;
+    assert( pBt->inTransaction==TRANS_WRITE );
+    assert( pBt->nTransaction>0 );
+    rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
+    if( rc!=SQLITE_OK ){
+      sqlite3BtreeLeave(p);
+      return rc;
+    }
+    pBt->inTransaction = TRANS_READ;
+    pBt->inStmt = 0;
+  }
+  unlockAllTables(p);
+
+  /* If the handle has any kind of transaction open, decrement the transaction
+  ** count of the shared btree. If the transaction count reaches 0, set
+  ** the shared state to TRANS_NONE. The unlockBtreeIfUnused() call below
+  ** will unlock the pager.
+  */
+  if( p->inTrans!=TRANS_NONE ){
+    pBt->nTransaction--;
+    if( 0==pBt->nTransaction ){
+      pBt->inTransaction = TRANS_NONE;
+    }
+  }
+
+  /* Set the handles current transaction state to TRANS_NONE and unlock
+  ** the pager if this call closed the only read or write transaction.
+  */
+  p->inTrans = TRANS_NONE;
+  unlockBtreeIfUnused(pBt);
+
+  btreeIntegrity(p);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Do both phases of a commit.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = sqlite3BtreeCommitPhaseOne(p, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3BtreeCommitPhaseTwo(p);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+#ifndef NDEBUG
+/*
+** Return the number of write-cursors open on this handle. This is for use
+** in assert() expressions, so it is only compiled if NDEBUG is not
+** defined.
+**
+** For the purposes of this routine, a write-cursor is any cursor that
+** is capable of writing to the databse.  That means the cursor was
+** originally opened for writing and the cursor has not be disabled
+** by having its state changed to CURSOR_FAULT.
+*/
+static int countWriteCursors(BtShared *pBt){
+  BtCursor *pCur;
+  int r = 0;
+  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
+    if( pCur->wrFlag && pCur->eState!=CURSOR_FAULT ) r++; 
+  }
+  return r;
+}
+#endif
+
+/*
+** This routine sets the state to CURSOR_FAULT and the error
+** code to errCode for every cursor on BtShared that pBtree
+** references.
+**
+** Every cursor is tripped, including cursors that belong
+** to other database connections that happen to be sharing
+** the cache with pBtree.
+**
+** This routine gets called when a rollback occurs.
+** All cursors using the same cache must be tripped
+** to prevent them from trying to use the btree after
+** the rollback.  The rollback may have deleted tables
+** or moved root pages, so it is not sufficient to
+** save the state of the cursor.  The cursor must be
+** invalidated.
+*/
+SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode){
+  BtCursor *p;
+  sqlite3BtreeEnter(pBtree);
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    clearCursorPosition(p);
+    p->eState = CURSOR_FAULT;
+    p->skip = errCode;
+  }
+  sqlite3BtreeLeave(pBtree);
+}
+
+/*
+** Rollback the transaction in progress.  All cursors will be
+** invalided by this operation.  Any attempt to use a cursor
+** that was open at the beginning of this operation will result
+** in an error.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+  MemPage *pPage1;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  rc = saveAllCursors(pBt, 0, 0);
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  if( rc!=SQLITE_OK ){
+    /* This is a horrible situation. An IO or malloc() error occured whilst
+    ** trying to save cursor positions. If this is an automatic rollback (as
+    ** the result of a constraint, malloc() failure or IO error) then 
+    ** the cache may be internally inconsistent (not contain valid trees) so
+    ** we cannot simply return the error to the caller. Instead, abort 
+    ** all queries that may be using any of the cursors that failed to save.
+    */
+    sqlite3BtreeTripAllCursors(p, rc);
+  }
+#endif
+  btreeIntegrity(p);
+  unlockAllTables(p);
+
+  if( p->inTrans==TRANS_WRITE ){
+    int rc2;
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    pBt->nTrunc = 0;
+#endif
+
+    assert( TRANS_WRITE==pBt->inTransaction );
+    rc2 = sqlite3PagerRollback(pBt->pPager);
+    if( rc2!=SQLITE_OK ){
+      rc = rc2;
+    }
+
+    /* The rollback may have destroyed the pPage1->aData value.  So
+    ** call sqlite3BtreeGetPage() on page 1 again to make
+    ** sure pPage1->aData is set correctly. */
+    if( sqlite3BtreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+      releasePage(pPage1);
+    }
+    assert( countWriteCursors(pBt)==0 );
+    pBt->inTransaction = TRANS_READ;
+  }
+
+  if( p->inTrans!=TRANS_NONE ){
+    assert( pBt->nTransaction>0 );
+    pBt->nTransaction--;
+    if( 0==pBt->nTransaction ){
+      pBt->inTransaction = TRANS_NONE;
+    }
+  }
+
+  p->inTrans = TRANS_NONE;
+  pBt->inStmt = 0;
+  unlockBtreeIfUnused(pBt);
+
+  btreeIntegrity(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Start a statement subtransaction.  The subtransaction can
+** can be rolled back independently of the main transaction.
+** You must start a transaction before starting a subtransaction.
+** The subtransaction is ended automatically if the main transaction
+** commits or rolls back.
+**
+** Only one subtransaction may be active at a time.  It is an error to try
+** to start a new subtransaction if another subtransaction is already active.
+**
+** Statement subtransactions are used around individual SQL statements
+** that are contained within a BEGIN...COMMIT block.  If a constraint
+** error occurs within the statement, the effect of that one statement
+** can be rolled back without having to rollback the entire transaction.
+*/
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  if( (p->inTrans!=TRANS_WRITE) || pBt->inStmt ){
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+  }else{
+    assert( pBt->inTransaction==TRANS_WRITE );
+    rc = pBt->readOnly ? SQLITE_OK : sqlite3PagerStmtBegin(pBt->pPager);
+    pBt->inStmt = 1;
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+/*
+** Commit the statment subtransaction currently in progress.  If no
+** subtransaction is active, this is a no-op.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitStmt(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  if( pBt->inStmt && !pBt->readOnly ){
+    rc = sqlite3PagerStmtCommit(pBt->pPager);
+  }else{
+    rc = SQLITE_OK;
+  }
+  pBt->inStmt = 0;
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Rollback the active statement subtransaction.  If no subtransaction
+** is active this routine is a no-op.
+**
+** All cursors will be invalidated by this operation.  Any attempt
+** to use a cursor that was open at the beginning of this operation
+** will result in an error.
+*/
+SQLITE_PRIVATE int sqlite3BtreeRollbackStmt(Btree *p){
+  int rc = SQLITE_OK;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  if( pBt->inStmt && !pBt->readOnly ){
+    rc = sqlite3PagerStmtRollback(pBt->pPager);
+    assert( countWriteCursors(pBt)==0 );
+    pBt->inStmt = 0;
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Create a new cursor for the BTree whose root is on the page
+** iTable.  The act of acquiring a cursor gets a read lock on 
+** the database file.
+**
+** If wrFlag==0, then the cursor can only be used for reading.
+** If wrFlag==1, then the cursor can be used for reading or for
+** writing if other conditions for writing are also met.  These
+** are the conditions that must be met in order for writing to
+** be allowed:
+**
+** 1:  The cursor must have been opened with wrFlag==1
+**
+** 2:  Other database connections that share the same pager cache
+**     but which are not in the READ_UNCOMMITTED state may not have
+**     cursors open with wrFlag==0 on the same table.  Otherwise
+**     the changes made by this write cursor would be visible to
+**     the read cursors in the other database connection.
+**
+** 3:  The database must be writable (not on read-only media)
+**
+** 4:  There must be an active transaction.
+**
+** No checking is done to make sure that page iTable really is the
+** root page of a b-tree.  If it is not, then the cursor acquired
+** will not work correctly.
+*/
+static int btreeCursor(
+  Btree *p,                              /* The btree */
+  int iTable,                            /* Root page of table to open */
+  int wrFlag,                            /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
+  BtCursor *pCur                         /* Space for new cursor */
+){
+  int rc;
+  BtShared *pBt = p->pBt;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  if( wrFlag ){
+    if( pBt->readOnly ){
+      return SQLITE_READONLY;
+    }
+    if( checkReadLocks(p, iTable, 0) ){
+      return SQLITE_LOCKED;
+    }
+  }
+
+  if( pBt->pPage1==0 ){
+    rc = lockBtreeWithRetry(p);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( pBt->readOnly && wrFlag ){
+      return SQLITE_READONLY;
+    }
+  }
+  pCur->pgnoRoot = (Pgno)iTable;
+  if( iTable==1 && sqlite3PagerPagecount(pBt->pPager)==0 ){
+    rc = SQLITE_EMPTY;
+    goto create_cursor_exception;
+  }
+  rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->pPage, 0);
+  if( rc!=SQLITE_OK ){
+    goto create_cursor_exception;
+  }
+
+  /* Now that no other errors can occur, finish filling in the BtCursor
+  ** variables, link the cursor into the BtShared list and set *ppCur (the
+  ** output argument to this function).
+  */
+  pCur->pKeyInfo = pKeyInfo;
+  pCur->pBtree = p;
+  pCur->pBt = pBt;
+  pCur->wrFlag = wrFlag;
+  pCur->pNext = pBt->pCursor;
+  if( pCur->pNext ){
+    pCur->pNext->pPrev = pCur;
+  }
+  pBt->pCursor = pCur;
+  pCur->eState = CURSOR_INVALID;
+
+  return SQLITE_OK;
+
+create_cursor_exception:
+  if( pCur ){
+    releasePage(pCur->pPage);
+  }
+  unlockBtreeIfUnused(pBt);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree *p,                                   /* The btree */
+  int iTable,                                 /* Root page of table to open */
+  int wrFlag,                                 /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
+  BtCursor *pCur                              /* Write new cursor here */
+){
+  int rc;
+  sqlite3BtreeEnter(p);
+  p->pBt->db = p->db;
+  rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(){
+  return sizeof(BtCursor);
+}
+
+
+
+/*
+** Close a cursor.  The read lock on the database file is released
+** when the last cursor is closed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
+  Btree *pBtree = pCur->pBtree;
+  if( pBtree ){
+    BtShared *pBt = pCur->pBt;
+    sqlite3BtreeEnter(pBtree);
+    pBt->db = pBtree->db;
+    clearCursorPosition(pCur);
+    if( pCur->pPrev ){
+      pCur->pPrev->pNext = pCur->pNext;
+    }else{
+      pBt->pCursor = pCur->pNext;
+    }
+    if( pCur->pNext ){
+      pCur->pNext->pPrev = pCur->pPrev;
+    }
+    releasePage(pCur->pPage);
+    unlockBtreeIfUnused(pBt);
+    invalidateOverflowCache(pCur);
+    /* sqlite3_free(pCur); */
+    sqlite3BtreeLeave(pBtree);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Make a temporary cursor by filling in the fields of pTempCur.
+** The temporary cursor is not on the cursor list for the Btree.
+*/
+SQLITE_PRIVATE void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur){
+  assert( cursorHoldsMutex(pCur) );
+  memcpy(pTempCur, pCur, sizeof(*pCur));
+  pTempCur->pNext = 0;
+  pTempCur->pPrev = 0;
+  if( pTempCur->pPage ){
+    sqlite3PagerRef(pTempCur->pPage->pDbPage);
+  }
+}
+
+/*
+** Delete a temporary cursor such as was made by the CreateTemporaryCursor()
+** function above.
+*/
+SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  if( pCur->pPage ){
+    sqlite3PagerUnref(pCur->pPage->pDbPage);
+  }
+}
+
+/*
+** Make sure the BtCursor* given in the argument has a valid
+** BtCursor.info structure.  If it is not already valid, call
+** sqlite3BtreeParseCell() to fill it in.
+**
+** BtCursor.info is a cache of the information in the current cell.
+** Using this cache reduces the number of calls to sqlite3BtreeParseCell().
+**
+** 2007-06-25:  There is a bug in some versions of MSVC that cause the
+** compiler to crash when getCellInfo() is implemented as a macro.
+** But there is a measureable speed advantage to using the macro on gcc
+** (when less compiler optimizations like -Os or -O0 are used and the
+** compiler is not doing agressive inlining.)  So we use a real function
+** for MSVC and a macro for everything else.  Ticket #2457.
+*/
+#ifndef NDEBUG
+  static void assertCellInfo(BtCursor *pCur){
+    CellInfo info;
+    memset(&info, 0, sizeof(info));
+    sqlite3BtreeParseCell(pCur->pPage, pCur->idx, &info);
+    assert( memcmp(&info, &pCur->info, sizeof(info))==0 );
+  }
+#else
+  #define assertCellInfo(x)
+#endif
+#ifdef _MSC_VER
+  /* Use a real function in MSVC to work around bugs in that compiler. */
+  static void getCellInfo(BtCursor *pCur){
+    if( pCur->info.nSize==0 ){
+      sqlite3BtreeParseCell(pCur->pPage, pCur->idx, &pCur->info);
+      pCur->validNKey = 1;
+    }else{
+      assertCellInfo(pCur);
+    }
+  }
+#else /* if not _MSC_VER */
+  /* Use a macro in all other compilers so that the function is inlined */
+#define getCellInfo(pCur)                                               \
+  if( pCur->info.nSize==0 ){                                            \
+    sqlite3BtreeParseCell(pCur->pPage, pCur->idx, &pCur->info);         \
+    pCur->validNKey = 1;                                                \
+  }else{                                                                \
+    assertCellInfo(pCur);                                               \
+  }
+#endif /* _MSC_VER */
+
+/*
+** Set *pSize to the size of the buffer needed to hold the value of
+** the key for the current entry.  If the cursor is not pointing
+** to a valid entry, *pSize is set to 0. 
+**
+** For a table with the INTKEY flag set, this routine returns the key
+** itself, not the number of bytes in the key.
+*/
+SQLITE_PRIVATE int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
+  int rc;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
+    if( pCur->eState==CURSOR_INVALID ){
+      *pSize = 0;
+    }else{
+      getCellInfo(pCur);
+      *pSize = pCur->info.nKey;
+    }
+  }
+  return rc;
+}
+
+/*
+** Set *pSize to the number of bytes of data in the entry the
+** cursor currently points to.  Always return SQLITE_OK.
+** Failure is not possible.  If the cursor is not currently
+** pointing to an entry (which can happen, for example, if
+** the database is empty) then *pSize is set to 0.
+*/
+SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
+  int rc;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
+    if( pCur->eState==CURSOR_INVALID ){
+      /* Not pointing at a valid entry - set *pSize to 0. */
+      *pSize = 0;
+    }else{
+      getCellInfo(pCur);
+      *pSize = pCur->info.nData;
+    }
+  }
+  return rc;
+}
+
+/*
+** Given the page number of an overflow page in the database (parameter
+** ovfl), this function finds the page number of the next page in the 
+** linked list of overflow pages. If possible, it uses the auto-vacuum
+** pointer-map data instead of reading the content of page ovfl to do so. 
+**
+** If an error occurs an SQLite error code is returned. Otherwise:
+**
+** Unless pPgnoNext is NULL, the page number of the next overflow 
+** page in the linked list is written to *pPgnoNext. If page ovfl
+** is the last page in its linked list, *pPgnoNext is set to zero. 
+**
+** If ppPage is not NULL, *ppPage is set to the MemPage* handle
+** for page ovfl. The underlying pager page may have been requested
+** with the noContent flag set, so the page data accessable via
+** this handle may not be trusted.
+*/
+static int getOverflowPage(
+  BtShared *pBt, 
+  Pgno ovfl,                   /* Overflow page */
+  MemPage **ppPage,            /* OUT: MemPage handle */
+  Pgno *pPgnoNext              /* OUT: Next overflow page number */
+){
+  Pgno next = 0;
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  /* One of these must not be NULL. Otherwise, why call this function? */
+  assert(ppPage || pPgnoNext);
+
+  /* If pPgnoNext is NULL, then this function is being called to obtain
+  ** a MemPage* reference only. No page-data is required in this case.
+  */
+  if( !pPgnoNext ){
+    return sqlite3BtreeGetPage(pBt, ovfl, ppPage, 1);
+  }
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* Try to find the next page in the overflow list using the
+  ** autovacuum pointer-map pages. Guess that the next page in 
+  ** the overflow list is page number (ovfl+1). If that guess turns 
+  ** out to be wrong, fall back to loading the data of page 
+  ** number ovfl to determine the next page number.
+  */
+  if( pBt->autoVacuum ){
+    Pgno pgno;
+    Pgno iGuess = ovfl+1;
+    u8 eType;
+
+    while( PTRMAP_ISPAGE(pBt, iGuess) || iGuess==PENDING_BYTE_PAGE(pBt) ){
+      iGuess++;
+    }
+
+    if( iGuess<=sqlite3PagerPagecount(pBt->pPager) ){
+      rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      if( eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
+        next = iGuess;
+      }
+    }
+  }
+#endif
+
+  if( next==0 || ppPage ){
+    MemPage *pPage = 0;
+
+    rc = sqlite3BtreeGetPage(pBt, ovfl, &pPage, next!=0);
+    assert(rc==SQLITE_OK || pPage==0);
+    if( next==0 && rc==SQLITE_OK ){
+      next = get4byte(pPage->aData);
+    }
+
+    if( ppPage ){
+      *ppPage = pPage;
+    }else{
+      releasePage(pPage);
+    }
+  }
+  *pPgnoNext = next;
+
+  return rc;
+}
+
+/*
+** Copy data from a buffer to a page, or from a page to a buffer.
+**
+** pPayload is a pointer to data stored on database page pDbPage.
+** If argument eOp is false, then nByte bytes of data are copied
+** from pPayload to the buffer pointed at by pBuf. If eOp is true,
+** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
+** of data are copied from the buffer pBuf to pPayload.
+**
+** SQLITE_OK is returned on success, otherwise an error code.
+*/
+static int copyPayload(
+  void *pPayload,           /* Pointer to page data */
+  void *pBuf,               /* Pointer to buffer */
+  int nByte,                /* Number of bytes to copy */
+  int eOp,                  /* 0 -> copy from page, 1 -> copy to page */
+  DbPage *pDbPage           /* Page containing pPayload */
+){
+  if( eOp ){
+    /* Copy data from buffer to page (a write operation) */
+    int rc = sqlite3PagerWrite(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    memcpy(pPayload, pBuf, nByte);
+  }else{
+    /* Copy data from page to buffer (a read operation) */
+    memcpy(pBuf, pPayload, nByte);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is used to read or overwrite payload information
+** for the entry that the pCur cursor is pointing to. If the eOp
+** parameter is 0, this is a read operation (data copied into
+** buffer pBuf). If it is non-zero, a write (data copied from
+** buffer pBuf).
+**
+** A total of "amt" bytes are read or written beginning at "offset".
+** Data is read to or from the buffer pBuf.
+**
+** This routine does not make a distinction between key and data.
+** It just reads or writes bytes from the payload area.  Data might 
+** appear on the main page or be scattered out on multiple overflow 
+** pages.
+**
+** If the BtCursor.isIncrblobHandle flag is set, and the current
+** cursor entry uses one or more overflow pages, this function
+** allocates space for and lazily popluates the overflow page-list 
+** cache array (BtCursor.aOverflow). Subsequent calls use this
+** cache to make seeking to the supplied offset more efficient.
+**
+** Once an overflow page-list cache has been allocated, it may be
+** invalidated if some other cursor writes to the same table, or if
+** the cursor is moved to a different row. Additionally, in auto-vacuum
+** mode, the following events may invalidate an overflow page-list cache.
+**
+**   * An incremental vacuum,
+**   * A commit in auto_vacuum="full" mode,
+**   * Creating a table (may require moving an overflow page).
+*/
+static int accessPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  int offset,          /* Begin reading this far into payload */
+  int amt,             /* Read this many bytes */
+  unsigned char *pBuf, /* Write the bytes into this buffer */ 
+  int skipKey,         /* offset begins at data if this is true */
+  int eOp              /* zero to read. non-zero to write. */
+){
+  unsigned char *aPayload;
+  int rc = SQLITE_OK;
+  u32 nKey;
+  int iIdx = 0;
+  MemPage *pPage = pCur->pPage;     /* Btree page of current cursor entry */
+  BtShared *pBt;                   /* Btree this cursor belongs to */
+
+  assert( pPage );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
+  assert( offset>=0 );
+  assert( cursorHoldsMutex(pCur) );
+
+  getCellInfo(pCur);
+  aPayload = pCur->info.pCell + pCur->info.nHeader;
+  nKey = (pPage->intKey ? 0 : pCur->info.nKey);
+
+  if( skipKey ){
+    offset += nKey;
+  }
+  if( offset+amt > nKey+pCur->info.nData ){
+    /* Trying to read or write past the end of the data is an error */
+    return SQLITE_ERROR;
+  }
+
+  /* Check if data must be read/written to/from the btree page itself. */
+  if( offset<pCur->info.nLocal ){
+    int a = amt;
+    if( a+offset>pCur->info.nLocal ){
+      a = pCur->info.nLocal - offset;
+    }
+    rc = copyPayload(&aPayload[offset], pBuf, a, eOp, pPage->pDbPage);
+    offset = 0;
+    pBuf += a;
+    amt -= a;
+  }else{
+    offset -= pCur->info.nLocal;
+  }
+
+  pBt = pCur->pBt;
+  if( rc==SQLITE_OK && amt>0 ){
+    const int ovflSize = pBt->usableSize - 4;  /* Bytes content per ovfl page */
+    Pgno nextPage;
+
+    nextPage = get4byte(&aPayload[pCur->info.nLocal]);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+    /* If the isIncrblobHandle flag is set and the BtCursor.aOverflow[]
+    ** has not been allocated, allocate it now. The array is sized at
+    ** one entry for each overflow page in the overflow chain. The
+    ** page number of the first overflow page is stored in aOverflow[0],
+    ** etc. A value of 0 in the aOverflow[] array means "not yet known"
+    ** (the cache is lazily populated).
+    */
+    if( pCur->isIncrblobHandle && !pCur->aOverflow ){
+      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
+      pCur->aOverflow = (Pgno *)sqlite3MallocZero(sizeof(Pgno)*nOvfl);
+      if( nOvfl && !pCur->aOverflow ){
+        rc = SQLITE_NOMEM;
+      }
+    }
+
+    /* If the overflow page-list cache has been allocated and the
+    ** entry for the first required overflow page is valid, skip
+    ** directly to it.
+    */
+    if( pCur->aOverflow && pCur->aOverflow[offset/ovflSize] ){
+      iIdx = (offset/ovflSize);
+      nextPage = pCur->aOverflow[iIdx];
+      offset = (offset%ovflSize);
+    }
+#endif
+
+    for( ; rc==SQLITE_OK && amt>0 && nextPage; iIdx++){
+
+#ifndef SQLITE_OMIT_INCRBLOB
+      /* If required, populate the overflow page-list cache. */
+      if( pCur->aOverflow ){
+        assert(!pCur->aOverflow[iIdx] || pCur->aOverflow[iIdx]==nextPage);
+        pCur->aOverflow[iIdx] = nextPage;
+      }
+#endif
+
+      if( offset>=ovflSize ){
+        /* The only reason to read this page is to obtain the page
+        ** number for the next page in the overflow chain. The page
+        ** data is not required. So first try to lookup the overflow
+        ** page-list cache, if any, then fall back to the getOverflowPage()
+        ** function.
+        */
+#ifndef SQLITE_OMIT_INCRBLOB
+        if( pCur->aOverflow && pCur->aOverflow[iIdx+1] ){
+          nextPage = pCur->aOverflow[iIdx+1];
+        } else 
+#endif
+          rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
+        offset -= ovflSize;
+      }else{
+        /* Need to read this page properly. It contains some of the
+        ** range of data that is being read (eOp==0) or written (eOp!=0).
+        */
+        DbPage *pDbPage;
+        int a = amt;
+        rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
+        if( rc==SQLITE_OK ){
+          aPayload = sqlite3PagerGetData(pDbPage);
+          nextPage = get4byte(aPayload);
+          if( a + offset > ovflSize ){
+            a = ovflSize - offset;
+          }
+          rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
+          sqlite3PagerUnref(pDbPage);
+          offset = 0;
+          amt -= a;
+          pBuf += a;
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && amt>0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  return rc;
+}
+
+/*
+** Read part of the key associated with cursor pCur.  Exactly
+** "amt" bytes will be transfered into pBuf[].  The transfer
+** begins at "offset".
+**
+** Return SQLITE_OK on success or an error code if anything goes
+** wrong.  An error is returned if "offset+amt" is larger than
+** the available payload.
+*/
+SQLITE_PRIVATE int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  int rc;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_VALID );
+    assert( pCur->pPage!=0 );
+    if( pCur->pPage->intKey ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+    assert( pCur->pPage->intKey==0 );
+    assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
+    rc = accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0, 0);
+  }
+  return rc;
+}
+
+/*
+** Read part of the data associated with cursor pCur.  Exactly
+** "amt" bytes will be transfered into pBuf[].  The transfer
+** begins at "offset".
+**
+** Return SQLITE_OK on success or an error code if anything goes
+** wrong.  An error is returned if "offset+amt" is larger than
+** the available payload.
+*/
+SQLITE_PRIVATE int sqlite3BtreeData(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  int rc;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_VALID );
+    assert( pCur->pPage!=0 );
+    assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
+    rc = accessPayload(pCur, offset, amt, pBuf, 1, 0);
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to payload information from the entry that the 
+** pCur cursor is pointing to.  The pointer is to the beginning of
+** the key if skipKey==0 and it points to the beginning of data if
+** skipKey==1.  The number of bytes of available key/data is written
+** into *pAmt.  If *pAmt==0, then the value returned will not be
+** a valid pointer.
+**
+** This routine is an optimization.  It is common for the entire key
+** and data to fit on the local page and for there to be no overflow
+** pages.  When that is so, this routine can be used to access the
+** key and data without making a copy.  If the key and/or data spills
+** onto overflow pages, then accessPayload() must be used to reassembly
+** the key/data and copy it into a preallocated buffer.
+**
+** The pointer returned by this routine looks directly into the cached
+** page of the database.  The data might change or move the next time
+** any btree routine is called.
+*/
+static const unsigned char *fetchPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  int *pAmt,           /* Write the number of available bytes here */
+  int skipKey          /* read beginning at data if this is true */
+){
+  unsigned char *aPayload;
+  MemPage *pPage;
+  u32 nKey;
+  int nLocal;
+
+  assert( pCur!=0 && pCur->pPage!=0 );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( cursorHoldsMutex(pCur) );
+  pPage = pCur->pPage;
+  assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
+  getCellInfo(pCur);
+  aPayload = pCur->info.pCell;
+  aPayload += pCur->info.nHeader;
+  if( pPage->intKey ){
+    nKey = 0;
+  }else{
+    nKey = pCur->info.nKey;
+  }
+  if( skipKey ){
+    aPayload += nKey;
+    nLocal = pCur->info.nLocal - nKey;
+  }else{
+    nLocal = pCur->info.nLocal;
+    if( nLocal>nKey ){
+      nLocal = nKey;
+    }
+  }
+  *pAmt = nLocal;
+  return aPayload;
+}
+
+
+/*
+** For the entry that cursor pCur is point to, return as
+** many bytes of the key or data as are available on the local
+** b-tree page.  Write the number of available bytes into *pAmt.
+**
+** The pointer returned is ephemeral.  The key/data may move
+** or be destroyed on the next call to any Btree routine,
+** including calls from other threads against the same cache.
+** Hence, a mutex on the BtShared should be held prior to calling
+** this routine.
+**
+** These routines is used to get quick access to key and data
+** in the common case where no overflow pages are used.
+*/
+SQLITE_PRIVATE const void *sqlite3BtreeKeyFetch(BtCursor *pCur, int *pAmt){
+  assert( cursorHoldsMutex(pCur) );
+  if( pCur->eState==CURSOR_VALID ){
+    return (const void*)fetchPayload(pCur, pAmt, 0);
+  }
+  return 0;
+}
+SQLITE_PRIVATE const void *sqlite3BtreeDataFetch(BtCursor *pCur, int *pAmt){
+  assert( cursorHoldsMutex(pCur) );
+  if( pCur->eState==CURSOR_VALID ){
+    return (const void*)fetchPayload(pCur, pAmt, 1);
+  }
+  return 0;
+}
+
+
+/*
+** Move the cursor down to a new child page.  The newPgno argument is the
+** page number of the child page to move to.
+*/
+static int moveToChild(BtCursor *pCur, u32 newPgno){
+  int rc;
+  MemPage *pNewPage;
+  MemPage *pOldPage;
+  BtShared *pBt = pCur->pBt;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  rc = getAndInitPage(pBt, newPgno, &pNewPage, pCur->pPage);
+  if( rc ) return rc;
+  pNewPage->idxParent = pCur->idx;
+  pOldPage = pCur->pPage;
+  pOldPage->idxShift = 0;
+  releasePage(pOldPage);
+  pCur->pPage = pNewPage;
+  pCur->idx = 0;
+  pCur->info.nSize = 0;
+  pCur->validNKey = 0;
+  if( pNewPage->nCell<1 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the page is the virtual root of its table.
+**
+** The virtual root page is the root page for most tables.  But
+** for the table rooted on page 1, sometime the real root page
+** is empty except for the right-pointer.  In such cases the
+** virtual root page is the page that the right-pointer of page
+** 1 is pointing to.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsRootPage(MemPage *pPage){
+  MemPage *pParent;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pParent = pPage->pParent;
+  if( pParent==0 ) return 1;
+  if( pParent->pgno>1 ) return 0;
+  if( get2byte(&pParent->aData[pParent->hdrOffset+3])==0 ) return 1;
+  return 0;
+}
+
+/*
+** Move the cursor up to the parent page.
+**
+** pCur->idx is set to the cell index that contains the pointer
+** to the page we are coming from.  If we are coming from the
+** right-most child page then pCur->idx is set to one more than
+** the largest cell index.
+*/
+SQLITE_PRIVATE void sqlite3BtreeMoveToParent(BtCursor *pCur){
+  MemPage *pParent;
+  MemPage *pPage;
+  int idxParent;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  pPage = pCur->pPage;
+  assert( pPage!=0 );
+  assert( !sqlite3BtreeIsRootPage(pPage) );
+  pParent = pPage->pParent;
+  assert( pParent!=0 );
+  idxParent = pPage->idxParent;
+  sqlite3PagerRef(pParent->pDbPage);
+  releasePage(pPage);
+  pCur->pPage = pParent;
+  pCur->info.nSize = 0;
+  pCur->validNKey = 0;
+  assert( pParent->idxShift==0 );
+  pCur->idx = idxParent;
+}
+
+/*
+** Move the cursor to the root page
+*/
+static int moveToRoot(BtCursor *pCur){
+  MemPage *pRoot;
+  int rc = SQLITE_OK;
+  Btree *p = pCur->pBtree;
+  BtShared *pBt = p->pBt;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
+  assert( CURSOR_VALID   < CURSOR_REQUIRESEEK );
+  assert( CURSOR_FAULT   > CURSOR_REQUIRESEEK );
+  if( pCur->eState>=CURSOR_REQUIRESEEK ){
+    if( pCur->eState==CURSOR_FAULT ){
+      return pCur->skip;
+    }
+    clearCursorPosition(pCur);
+  }
+  pRoot = pCur->pPage;
+  if( pRoot && pRoot->pgno==pCur->pgnoRoot ){
+    assert( pRoot->isInit );
+  }else{
+    if( 
+      SQLITE_OK!=(rc = getAndInitPage(pBt, pCur->pgnoRoot, &pRoot, 0))
+    ){
+      pCur->eState = CURSOR_INVALID;
+      return rc;
+    }
+    releasePage(pCur->pPage);
+    pCur->pPage = pRoot;
+  }
+  pCur->idx = 0;
+  pCur->info.nSize = 0;
+  pCur->atLast = 0;
+  pCur->validNKey = 0;
+  if( pRoot->nCell==0 && !pRoot->leaf ){
+    Pgno subpage;
+    assert( pRoot->pgno==1 );
+    subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
+    assert( subpage>0 );
+    pCur->eState = CURSOR_VALID;
+    rc = moveToChild(pCur, subpage);
+  }
+  pCur->eState = ((pCur->pPage->nCell>0)?CURSOR_VALID:CURSOR_INVALID);
+  return rc;
+}
+
+/*
+** Move the cursor down to the left-most leaf entry beneath the
+** entry to which it is currently pointing.
+**
+** The left-most leaf is the one with the smallest key - the first
+** in ascending order.
+*/
+static int moveToLeftmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( rc==SQLITE_OK && !(pPage = pCur->pPage)->leaf ){
+    assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
+    pgno = get4byte(findCell(pPage, pCur->idx));
+    rc = moveToChild(pCur, pgno);
+  }
+  return rc;
+}
+
+/*
+** Move the cursor down to the right-most leaf entry beneath the
+** page to which it is currently pointing.  Notice the difference
+** between moveToLeftmost() and moveToRightmost().  moveToLeftmost()
+** finds the left-most entry beneath the *entry* whereas moveToRightmost()
+** finds the right-most entry beneath the *page*.
+**
+** The right-most entry is the one with the largest key - the last
+** key in ascending order.
+*/
+static int moveToRightmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( rc==SQLITE_OK && !(pPage = pCur->pPage)->leaf ){
+    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    pCur->idx = pPage->nCell;
+    rc = moveToChild(pCur, pgno);
+  }
+  if( rc==SQLITE_OK ){
+    pCur->idx = pPage->nCell - 1;
+    pCur->info.nSize = 0;
+    pCur->validNKey = 0;
+  }
+  return SQLITE_OK;
+}
+
+/* Move the cursor to the first entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
+  int rc;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    if( pCur->eState==CURSOR_INVALID ){
+      assert( pCur->pPage->nCell==0 );
+      *pRes = 1;
+      rc = SQLITE_OK;
+    }else{
+      assert( pCur->pPage->nCell>0 );
+      *pRes = 0;
+      rc = moveToLeftmost(pCur);
+    }
+  }
+  return rc;
+}
+
+/* Move the cursor to the last entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
+  int rc;
+ 
+  assert( cursorHoldsMutex(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    if( CURSOR_INVALID==pCur->eState ){
+      assert( pCur->pPage->nCell==0 );
+      *pRes = 1;
+    }else{
+      assert( pCur->eState==CURSOR_VALID );
+      *pRes = 0;
+      rc = moveToRightmost(pCur);
+      getCellInfo(pCur);
+      pCur->atLast = rc==SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/* Move the cursor so that it points to an entry near the key 
+** specified by pKey/nKey/pUnKey. Return a success code.
+**
+** For INTKEY tables, only the nKey parameter is used.  pKey 
+** and pUnKey must be NULL.  For index tables, either pUnKey
+** must point to a key that has already been unpacked, or else
+** pKey/nKey describes a blob containing the key.
+**
+** If an exact match is not found, then the cursor is always
+** left pointing at a leaf page which would hold the entry if it
+** were present.  The cursor might point to an entry that comes
+** before or after the key.
+**
+** The result of comparing the key with the entry to which the
+** cursor is written to *pRes if pRes!=NULL.  The meaning of
+** this value is as follows:
+**
+**     *pRes<0      The cursor is left pointing at an entry that
+**                  is smaller than pKey or if the table is empty
+**                  and the cursor is therefore left point to nothing.
+**
+**     *pRes==0     The cursor is left pointing at an entry that
+**                  exactly matches pKey.
+**
+**     *pRes>0      The cursor is left pointing at an entry that
+**                  is larger than pKey.
+**
+*/
+SQLITE_PRIVATE int sqlite3BtreeMoveto(
+  BtCursor *pCur,        /* The cursor to be moved */
+  const void *pKey,      /* The key content for indices.  Not used by tables */
+  UnpackedRecord *pUnKey,/* Unpacked version of pKey */
+  i64 nKey,              /* Size of pKey.  Or the key for tables */
+  int biasRight,         /* If true, bias the search to the high end */
+  int *pRes              /* Search result flag */
+){
+  int rc;
+  char aSpace[200];
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* If the cursor is already positioned at the point we are trying
+  ** to move to, then just return without doing any work */
+  if( pCur->eState==CURSOR_VALID && pCur->validNKey && pCur->pPage->intKey ){
+    if( pCur->info.nKey==nKey ){
+      *pRes = 0;
+      return SQLITE_OK;
+    }
+    if( pCur->atLast && pCur->info.nKey<nKey ){
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+  }
+
+
+  rc = moveToRoot(pCur);
+  if( rc ){
+    return rc;
+  }
+  assert( pCur->pPage );
+  assert( pCur->pPage->isInit );
+  if( pCur->eState==CURSOR_INVALID ){
+    *pRes = -1;
+    assert( pCur->pPage->nCell==0 );
+    return SQLITE_OK;
+  }
+  if( pCur->pPage->intKey ){
+    /* We are given an SQL table to search.  The key is the integer
+    ** rowid contained in nKey.  pKey and pUnKey should both be NULL */
+    assert( pUnKey==0 );
+    assert( pKey==0 );
+  }else if( pUnKey==0 ){
+    /* We are to search an SQL index using a key encoded as a blob.
+    ** The blob is found at pKey and is nKey bytes in length.  Unpack
+    ** this key so that we can use it. */
+    assert( pKey!=0 );
+    pUnKey = sqlite3VdbeRecordUnpack(pCur->pKeyInfo, nKey, pKey,
+                                   aSpace, sizeof(aSpace));
+    if( pUnKey==0 ) return SQLITE_NOMEM;
+  }else{
+    /* We are to search an SQL index using a key that is already unpacked
+    ** and handed to us in pUnKey. */
+    assert( pKey==0 );
+  }
+  for(;;){
+    int lwr, upr;
+    Pgno chldPg;
+    MemPage *pPage = pCur->pPage;
+    int c = -1;  /* pRes return if table is empty must be -1 */
+    lwr = 0;
+    upr = pPage->nCell-1;
+    if( !pPage->intKey && pUnKey==0 ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto moveto_finish;
+    }
+    if( biasRight ){
+      pCur->idx = upr;
+    }else{
+      pCur->idx = (upr+lwr)/2;
+    }
+    if( lwr<=upr ) for(;;){
+      void *pCellKey;
+      i64 nCellKey;
+      pCur->info.nSize = 0;
+      pCur->validNKey = 1;
+      if( pPage->intKey ){
+        u8 *pCell;
+        pCell = findCell(pPage, pCur->idx) + pPage->childPtrSize;
+        if( pPage->hasData ){
+          u32 dummy;
+          pCell += getVarint32(pCell, dummy);
+        }
+        getVarint(pCell, (u64*)&nCellKey);
+        if( nCellKey==nKey ){
+          c = 0;
+        }else if( nCellKey<nKey ){
+          c = -1;
+        }else{
+          assert( nCellKey>nKey );
+          c = +1;
+        }
+      }else{
+        int available;
+        pCellKey = (void *)fetchPayload(pCur, &available, 0);
+        nCellKey = pCur->info.nKey;
+        if( available>=nCellKey ){
+          c = sqlite3VdbeRecordCompare(nCellKey, pCellKey, pUnKey);
+        }else{
+          pCellKey = sqlite3_malloc( nCellKey );
+          if( pCellKey==0 ){
+            rc = SQLITE_NOMEM;
+            goto moveto_finish;
+          }
+          rc = sqlite3BtreeKey(pCur, 0, nCellKey, (void *)pCellKey);
+          c = sqlite3VdbeRecordCompare(nCellKey, pCellKey, pUnKey);
+          sqlite3_free(pCellKey);
+          if( rc ) goto moveto_finish;
+        }
+      }
+      if( c==0 ){
+        pCur->info.nKey = nCellKey;
+        if( pPage->leafData && !pPage->leaf ){
+          lwr = pCur->idx;
+          upr = lwr - 1;
+          break;
+        }else{
+          if( pRes ) *pRes = 0;
+          rc = SQLITE_OK;
+          goto moveto_finish;
+        }
+      }
+      if( c<0 ){
+        lwr = pCur->idx+1;
+      }else{
+        upr = pCur->idx-1;
+      }
+      if( lwr>upr ){
+        pCur->info.nKey = nCellKey;
+        break;
+      }
+      pCur->idx = (lwr+upr)/2;
+    }
+    assert( lwr==upr+1 );
+    assert( pPage->isInit );
+    if( pPage->leaf ){
+      chldPg = 0;
+    }else if( lwr>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage, lwr));
+    }
+    if( chldPg==0 ){
+      assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
+      if( pRes ) *pRes = c;
+      rc = SQLITE_OK;
+      goto moveto_finish;
+    }
+    pCur->idx = lwr;
+    pCur->info.nSize = 0;
+    pCur->validNKey = 0;
+    rc = moveToChild(pCur, chldPg);
+    if( rc ) goto moveto_finish;
+  }
+moveto_finish:
+  if( pKey ){
+    /* If we created our own unpacked key at the top of this
+    ** procedure, then destroy that key before returning. */
+    sqlite3VdbeDeleteUnpackedRecord(pUnKey);
+  }
+  return rc;
+}
+
+
+/*
+** Return TRUE if the cursor is not pointing at an entry of the table.
+**
+** TRUE will be returned after a call to sqlite3BtreeNext() moves
+** past the last entry in the table or sqlite3BtreePrev() moves past
+** the first entry.  TRUE is also returned if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
+  /* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
+  ** have been deleted? This API will need to change to return an error code
+  ** as well as the boolean result value.
+  */
+  return (CURSOR_VALID!=pCur->eState);
+}
+
+/*
+** Return the database connection handle for a cursor.
+*/
+SQLITE_PRIVATE sqlite3 *sqlite3BtreeCursorDb(const BtCursor *pCur){
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  return pCur->pBtree->db;
+}
+
+/*
+** Advance the cursor to the next entry in the database.  If
+** successful then set *pRes=0.  If the cursor
+** was already pointing to the last entry in the database before
+** this routine was called, then set *pRes=1.
+*/
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
+  int rc;
+  MemPage *pPage;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( pRes!=0 );
+  pPage = pCur->pPage;
+  if( CURSOR_INVALID==pCur->eState ){
+    *pRes = 1;
+    return SQLITE_OK;
+  }
+  if( pCur->skip>0 ){
+    pCur->skip = 0;
+    *pRes = 0;
+    return SQLITE_OK;
+  }
+  pCur->skip = 0;
+
+  assert( pPage->isInit );
+  assert( pCur->idx<pPage->nCell );
+
+  pCur->idx++;
+  pCur->info.nSize = 0;
+  pCur->validNKey = 0;
+  if( pCur->idx>=pPage->nCell ){
+    if( !pPage->leaf ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+      if( rc ) return rc;
+      rc = moveToLeftmost(pCur);
+      *pRes = 0;
+      return rc;
+    }
+    do{
+      if( sqlite3BtreeIsRootPage(pPage) ){
+        *pRes = 1;
+        pCur->eState = CURSOR_INVALID;
+        return SQLITE_OK;
+      }
+      sqlite3BtreeMoveToParent(pCur);
+      pPage = pCur->pPage;
+    }while( pCur->idx>=pPage->nCell );
+    *pRes = 0;
+    if( pPage->leafData ){
+      rc = sqlite3BtreeNext(pCur, pRes);
+    }else{
+      rc = SQLITE_OK;
+    }
+    return rc;
+  }
+  *pRes = 0;
+  if( pPage->leaf ){
+    return SQLITE_OK;
+  }
+  rc = moveToLeftmost(pCur);
+  return rc;
+}
+
+
+/*
+** Step the cursor to the back to the previous entry in the database.  If
+** successful then set *pRes=0.  If the cursor
+** was already pointing to the first entry in the database before
+** this routine was called, then set *pRes=1.
+*/
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
+  int rc;
+  Pgno pgno;
+  MemPage *pPage;
+
+  assert( cursorHoldsMutex(pCur) );
+  rc = restoreOrClearCursorPosition(pCur);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pCur->atLast = 0;
+  if( CURSOR_INVALID==pCur->eState ){
+    *pRes = 1;
+    return SQLITE_OK;
+  }
+  if( pCur->skip<0 ){
+    pCur->skip = 0;
+    *pRes = 0;
+    return SQLITE_OK;
+  }
+  pCur->skip = 0;
+
+  pPage = pCur->pPage;
+  assert( pPage->isInit );
+  assert( pCur->idx>=0 );
+  if( !pPage->leaf ){
+    pgno = get4byte( findCell(pPage, pCur->idx) );
+    rc = moveToChild(pCur, pgno);
+    if( rc ){
+      return rc;
+    }
+    rc = moveToRightmost(pCur);
+  }else{
+    while( pCur->idx==0 ){
+      if( sqlite3BtreeIsRootPage(pPage) ){
+        pCur->eState = CURSOR_INVALID;
+        *pRes = 1;
+        return SQLITE_OK;
+      }
+      sqlite3BtreeMoveToParent(pCur);
+      pPage = pCur->pPage;
+    }
+    pCur->idx--;
+    pCur->info.nSize = 0;
+    pCur->validNKey = 0;
+    if( pPage->leafData && !pPage->leaf ){
+      rc = sqlite3BtreePrevious(pCur, pRes);
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+  *pRes = 0;
+  return rc;
+}
+
+/*
+** Allocate a new page from the database file.
+**
+** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
+** has already been called on the new page.)  The new page has also
+** been referenced and the calling routine is responsible for calling
+** sqlite3PagerUnref() on the new page when it is done.
+**
+** SQLITE_OK is returned on success.  Any other return value indicates
+** an error.  *ppPage and *pPgno are undefined in the event of an error.
+** Do not invoke sqlite3PagerUnref() on *ppPage if an error is returned.
+**
+** If the "nearby" parameter is not 0, then a (feeble) effort is made to 
+** locate a page close to the page number "nearby".  This can be used in an
+** attempt to keep related pages close to each other in the database file,
+** which in turn can make database access faster.
+**
+** If the "exact" parameter is not 0, and the page-number nearby exists 
+** anywhere on the free-list, then it is guarenteed to be returned. This
+** is only used by auto-vacuum databases when allocating a new table.
+*/
+static int allocateBtreePage(
+  BtShared *pBt, 
+  MemPage **ppPage, 
+  Pgno *pPgno, 
+  Pgno nearby,
+  u8 exact
+){
+  MemPage *pPage1;
+  int rc;
+  int n;     /* Number of pages on the freelist */
+  int k;     /* Number of leaves on the trunk of the freelist */
+  MemPage *pTrunk = 0;
+  MemPage *pPrevTrunk = 0;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  pPage1 = pBt->pPage1;
+  n = get4byte(&pPage1->aData[36]);
+  if( n>0 ){
+    /* There are pages on the freelist.  Reuse one of those pages. */
+    Pgno iTrunk;
+    u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
+    
+    /* If the 'exact' parameter was true and a query of the pointer-map
+    ** shows that the page 'nearby' is somewhere on the free-list, then
+    ** the entire-list will be searched for that page.
+    */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( exact && nearby<=sqlite3PagerPagecount(pBt->pPager) ){
+      u8 eType;
+      assert( nearby>0 );
+      assert( pBt->autoVacuum );
+      rc = ptrmapGet(pBt, nearby, &eType, 0);
+      if( rc ) return rc;
+      if( eType==PTRMAP_FREEPAGE ){
+        searchList = 1;
+      }
+      *pPgno = nearby;
+    }
+#endif
+
+    /* Decrement the free-list count by 1. Set iTrunk to the index of the
+    ** first free-list trunk page. iPrevTrunk is initially 1.
+    */
+    rc = sqlite3PagerWrite(pPage1->pDbPage);
+    if( rc ) return rc;
+    put4byte(&pPage1->aData[36], n-1);
+
+    /* The code within this loop is run only once if the 'searchList' variable
+    ** is not true. Otherwise, it runs once for each trunk-page on the
+    ** free-list until the page 'nearby' is located.
+    */
+    do {
+      pPrevTrunk = pTrunk;
+      if( pPrevTrunk ){
+        iTrunk = get4byte(&pPrevTrunk->aData[0]);
+      }else{
+        iTrunk = get4byte(&pPage1->aData[32]);
+      }
+      rc = sqlite3BtreeGetPage(pBt, iTrunk, &pTrunk, 0);
+      if( rc ){
+        pTrunk = 0;
+        goto end_allocate_page;
+      }
+
+      k = get4byte(&pTrunk->aData[4]);
+      if( k==0 && !searchList ){
+        /* The trunk has no leaves and the list is not being searched. 
+        ** So extract the trunk page itself and use it as the newly 
+        ** allocated page */
+        assert( pPrevTrunk==0 );
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        *pPgno = iTrunk;
+        memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+        *ppPage = pTrunk;
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
+      }else if( k>pBt->usableSize/4 - 8 ){
+        /* Value of k is out of range.  Database corruption */
+        rc = SQLITE_CORRUPT_BKPT;
+        goto end_allocate_page;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      }else if( searchList && nearby==iTrunk ){
+        /* The list is being searched and this trunk page is the page
+        ** to allocate, regardless of whether it has leaves.
+        */
+        assert( *pPgno==iTrunk );
+        *ppPage = pTrunk;
+        searchList = 0;
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        if( k==0 ){
+          if( !pPrevTrunk ){
+            memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+          }else{
+            memcpy(&pPrevTrunk->aData[0], &pTrunk->aData[0], 4);
+          }
+        }else{
+          /* The trunk page is required by the caller but it contains 
+          ** pointers to free-list leaves. The first leaf becomes a trunk
+          ** page in this case.
+          */
+          MemPage *pNewTrunk;
+          Pgno iNewTrunk = get4byte(&pTrunk->aData[8]);
+          rc = sqlite3BtreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0);
+          if( rc!=SQLITE_OK ){
+            goto end_allocate_page;
+          }
+          rc = sqlite3PagerWrite(pNewTrunk->pDbPage);
+          if( rc!=SQLITE_OK ){
+            releasePage(pNewTrunk);
+            goto end_allocate_page;
+          }
+          memcpy(&pNewTrunk->aData[0], &pTrunk->aData[0], 4);
+          put4byte(&pNewTrunk->aData[4], k-1);
+          memcpy(&pNewTrunk->aData[8], &pTrunk->aData[12], (k-1)*4);
+          releasePage(pNewTrunk);
+          if( !pPrevTrunk ){
+            put4byte(&pPage1->aData[32], iNewTrunk);
+          }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc ){
+              goto end_allocate_page;
+            }
+            put4byte(&pPrevTrunk->aData[0], iNewTrunk);
+          }
+        }
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
+#endif
+      }else{
+        /* Extract a leaf from the trunk */
+        int closest;
+        Pgno iPage;
+        unsigned char *aData = pTrunk->aData;
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        if( nearby>0 ){
+          int i, dist;
+          closest = 0;
+          dist = get4byte(&aData[8]) - nearby;
+          if( dist<0 ) dist = -dist;
+          for(i=1; i<k; i++){
+            int d2 = get4byte(&aData[8+i*4]) - nearby;
+            if( d2<0 ) d2 = -d2;
+            if( d2<dist ){
+              closest = i;
+              dist = d2;
+            }
+          }
+        }else{
+          closest = 0;
+        }
+
+        iPage = get4byte(&aData[8+closest*4]);
+        if( !searchList || iPage==nearby ){
+          *pPgno = iPage;
+          if( *pPgno>sqlite3PagerPagecount(pBt->pPager) ){
+            /* Free page off the end of the file */
+            rc = SQLITE_CORRUPT_BKPT;
+            goto end_allocate_page;
+          }
+          TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
+                 ": %d more free pages\n",
+                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
+          if( closest<k-1 ){
+            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
+          }
+          put4byte(&aData[4], k-1);
+          rc = sqlite3BtreeGetPage(pBt, *pPgno, ppPage, 1);
+          if( rc==SQLITE_OK ){
+            sqlite3PagerDontRollback((*ppPage)->pDbPage);
+            rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+            if( rc!=SQLITE_OK ){
+              releasePage(*ppPage);
+            }
+          }
+          searchList = 0;
+        }
+      }
+      releasePage(pPrevTrunk);
+      pPrevTrunk = 0;
+    }while( searchList );
+  }else{
+    /* There are no pages on the freelist, so create a new page at the
+    ** end of the file */
+    *pPgno = sqlite3PagerPagecount(pBt->pPager) + 1;
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->nTrunc ){
+      /* An incr-vacuum has already run within this transaction. So the
+      ** page to allocate is not from the physical end of the file, but
+      ** at pBt->nTrunc. 
+      */
+      *pPgno = pBt->nTrunc+1;
+      if( *pPgno==PENDING_BYTE_PAGE(pBt) ){
+        (*pPgno)++;
+      }
+    }
+    if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, *pPgno) ){
+      /* If *pPgno refers to a pointer-map page, allocate two new pages
+      ** at the end of the file instead of one. The first allocated page
+      ** becomes a new pointer-map page, the second is used by the caller.
+      */
+      TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", *pPgno));
+      assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
+      (*pPgno)++;
+      if( *pPgno==PENDING_BYTE_PAGE(pBt) ){ (*pPgno)++; }
+    }
+    if( pBt->nTrunc ){
+      pBt->nTrunc = *pPgno;
+    }
+#endif
+
+    assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
+    rc = sqlite3BtreeGetPage(pBt, *pPgno, ppPage, 0);
+    if( rc ) return rc;
+    rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(*ppPage);
+    }
+    TRACE(("ALLOCATE: %d from end of file\n", *pPgno));
+  }
+
+  assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
+
+end_allocate_page:
+  releasePage(pTrunk);
+  releasePage(pPrevTrunk);
+  return rc;
+}
+
+/*
+** Add a page of the database file to the freelist.
+**
+** sqlite3PagerUnref() is NOT called for pPage.
+*/
+static int freePage(MemPage *pPage){
+  BtShared *pBt = pPage->pBt;
+  MemPage *pPage1 = pBt->pPage1;
+  int rc, n, k;
+
+  /* Prepare the page for freeing */
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->pgno>1 );
+  pPage->isInit = 0;
+  releasePage(pPage->pParent);
+  pPage->pParent = 0;
+
+  /* Increment the free page count on pPage1 */
+  rc = sqlite3PagerWrite(pPage1->pDbPage);
+  if( rc ) return rc;
+  n = get4byte(&pPage1->aData[36]);
+  put4byte(&pPage1->aData[36], n+1);
+
+#ifdef SQLITE_SECURE_DELETE
+  /* If the SQLITE_SECURE_DELETE compile-time option is enabled, then
+  ** always fully overwrite deleted information with zeros.
+  */
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc ) return rc;
+  memset(pPage->aData, 0, pPage->pBt->pageSize);
+#endif
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* If the database supports auto-vacuum, write an entry in the pointer-map
+  ** to indicate that the page is free.
+  */
+  if( pBt->autoVacuum ){
+    rc = ptrmapPut(pBt, pPage->pgno, PTRMAP_FREEPAGE, 0);
+    if( rc ) return rc;
+  }
+#endif
+
+  if( n==0 ){
+    /* This is the first free page */
+    rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc ) return rc;
+    memset(pPage->aData, 0, 8);
+    put4byte(&pPage1->aData[32], pPage->pgno);
+    TRACE(("FREE-PAGE: %d first\n", pPage->pgno));
+  }else{
+    /* Other free pages already exist.  Retrive the first trunk page
+    ** of the freelist and find out how many leaves it has. */
+    MemPage *pTrunk;
+    rc = sqlite3BtreeGetPage(pBt, get4byte(&pPage1->aData[32]), &pTrunk, 0);
+    if( rc ) return rc;
+    k = get4byte(&pTrunk->aData[4]);
+    if( k>=pBt->usableSize/4 - 8 ){
+      /* The trunk is full.  Turn the page being freed into a new
+      ** trunk page with no leaves. */
+      rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc==SQLITE_OK ){
+        put4byte(pPage->aData, pTrunk->pgno);
+        put4byte(&pPage->aData[4], 0);
+        put4byte(&pPage1->aData[32], pPage->pgno);
+        TRACE(("FREE-PAGE: %d new trunk page replacing %d\n",
+                pPage->pgno, pTrunk->pgno));
+      }
+    }else if( k<0 ){
+      rc = SQLITE_CORRUPT;
+    }else{
+      /* Add the newly freed page as a leaf on the current trunk */
+      rc = sqlite3PagerWrite(pTrunk->pDbPage);
+      if( rc==SQLITE_OK ){
+        put4byte(&pTrunk->aData[4], k+1);
+        put4byte(&pTrunk->aData[8+k*4], pPage->pgno);
+#ifndef SQLITE_SECURE_DELETE
+        sqlite3PagerDontWrite(pPage->pDbPage);
+#endif
+      }
+      TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
+    }
+    releasePage(pTrunk);
+  }
+  return rc;
+}
+
+/*
+** Free any overflow pages associated with the given Cell.
+*/
+static int clearCell(MemPage *pPage, unsigned char *pCell){
+  BtShared *pBt = pPage->pBt;
+  CellInfo info;
+  Pgno ovflPgno;
+  int rc;
+  int nOvfl;
+  int ovflPageSize;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  if( info.iOverflow==0 ){
+    return SQLITE_OK;  /* No overflow pages. Return without doing anything */
+  }
+  ovflPgno = get4byte(&pCell[info.iOverflow]);
+  ovflPageSize = pBt->usableSize - 4;
+  nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
+  assert( ovflPgno==0 || nOvfl>0 );
+  while( nOvfl-- ){
+    MemPage *pOvfl;
+    if( ovflPgno==0 || ovflPgno>sqlite3PagerPagecount(pBt->pPager) ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    rc = getOverflowPage(pBt, ovflPgno, &pOvfl, (nOvfl==0)?0:&ovflPgno);
+    if( rc ) return rc;
+    rc = freePage(pOvfl);
+    sqlite3PagerUnref(pOvfl->pDbPage);
+    if( rc ) return rc;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Create the byte sequence used to represent a cell on page pPage
+** and write that byte sequence into pCell[].  Overflow pages are
+** allocated and filled in as necessary.  The calling procedure
+** is responsible for making sure sufficient space has been allocated
+** for pCell[].
+**
+** Note that pCell does not necessary need to point to the pPage->aData
+** area.  pCell might point to some temporary storage.  The cell will
+** be constructed in this temporary area then copied into pPage->aData
+** later.
+*/
+static int fillInCell(
+  MemPage *pPage,                /* The page that contains the cell */
+  unsigned char *pCell,          /* Complete text of the cell */
+  const void *pKey, i64 nKey,    /* The key */
+  const void *pData,int nData,   /* The data */
+  int nZero,                     /* Extra zero bytes to append to pData */
+  int *pnSize                    /* Write cell size here */
+){
+  int nPayload;
+  const u8 *pSrc;
+  int nSrc, n, rc;
+  int spaceLeft;
+  MemPage *pOvfl = 0;
+  MemPage *pToRelease = 0;
+  unsigned char *pPrior;
+  unsigned char *pPayload;
+  BtShared *pBt = pPage->pBt;
+  Pgno pgnoOvfl = 0;
+  int nHeader;
+  CellInfo info;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  /* Fill in the header. */
+  nHeader = 0;
+  if( !pPage->leaf ){
+    nHeader += 4;
+  }
+  if( pPage->hasData ){
+    nHeader += putVarint(&pCell[nHeader], nData+nZero);
+  }else{
+    nData = nZero = 0;
+  }
+  nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
+  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  assert( info.nHeader==nHeader );
+  assert( info.nKey==nKey );
+  assert( info.nData==nData+nZero );
+  
+  /* Fill in the payload */
+  nPayload = nData + nZero;
+  if( pPage->intKey ){
+    pSrc = pData;
+    nSrc = nData;
+    nData = 0;
+  }else{
+    nPayload += nKey;
+    pSrc = pKey;
+    nSrc = nKey;
+  }
+  *pnSize = info.nSize;
+  spaceLeft = info.nLocal;
+  pPayload = &pCell[nHeader];
+  pPrior = &pCell[info.iOverflow];
+
+  while( nPayload>0 ){
+    if( spaceLeft==0 ){
+      int isExact = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
+      if( pBt->autoVacuum ){
+        do{
+          pgnoOvfl++;
+        } while( 
+          PTRMAP_ISPAGE(pBt, pgnoOvfl) || pgnoOvfl==PENDING_BYTE_PAGE(pBt) 
+        );
+        if( pgnoOvfl>1 ){
+          /* isExact = 1; */
+        }
+      }
+#endif
+      rc = allocateBtreePage(pBt, &pOvfl, &pgnoOvfl, pgnoOvfl, isExact);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the database supports auto-vacuum, and the second or subsequent
+      ** overflow page is being allocated, add an entry to the pointer-map
+      ** for that page now. 
+      **
+      ** If this is the first overflow page, then write a partial entry 
+      ** to the pointer-map. If we write nothing to this pointer-map slot,
+      ** then the optimistic overflow chain processing in clearCell()
+      ** may misinterpret the uninitialised values and delete the
+      ** wrong pages from the database.
+      */
+      if( pBt->autoVacuum && rc==SQLITE_OK ){
+        u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
+        rc = ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap);
+        if( rc ){
+          releasePage(pOvfl);
+        }
+      }
+#endif
+      if( rc ){
+        releasePage(pToRelease);
+        return rc;
+      }
+      put4byte(pPrior, pgnoOvfl);
+      releasePage(pToRelease);
+      pToRelease = pOvfl;
+      pPrior = pOvfl->aData;
+      put4byte(pPrior, 0);
+      pPayload = &pOvfl->aData[4];
+      spaceLeft = pBt->usableSize - 4;
+    }
+    n = nPayload;
+    if( n>spaceLeft ) n = spaceLeft;
+    if( nSrc>0 ){
+      if( n>nSrc ) n = nSrc;
+      assert( pSrc );
+      memcpy(pPayload, pSrc, n);
+    }else{
+      memset(pPayload, 0, n);
+    }
+    nPayload -= n;
+    pPayload += n;
+    pSrc += n;
+    nSrc -= n;
+    spaceLeft -= n;
+    if( nSrc==0 ){
+      nSrc = nData;
+      pSrc = pData;
+    }
+  }
+  releasePage(pToRelease);
+  return SQLITE_OK;
+}
+
+/*
+** Change the MemPage.pParent pointer on the page whose number is
+** given in the second argument so that MemPage.pParent holds the
+** pointer in the third argument.
+*/
+static int reparentPage(BtShared *pBt, Pgno pgno, MemPage *pNewParent, int idx){
+  MemPage *pThis;
+  DbPage *pDbPage;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pNewParent!=0 );
+  if( pgno==0 ) return SQLITE_OK;
+  assert( pBt->pPager!=0 );
+  pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
+  if( pDbPage ){
+    pThis = (MemPage *)sqlite3PagerGetExtra(pDbPage);
+    if( pThis->isInit ){
+      assert( pThis->aData==sqlite3PagerGetData(pDbPage) );
+      if( pThis->pParent!=pNewParent ){
+        if( pThis->pParent ) sqlite3PagerUnref(pThis->pParent->pDbPage);
+        pThis->pParent = pNewParent;
+        sqlite3PagerRef(pNewParent->pDbPage);
+      }
+      pThis->idxParent = idx;
+    }
+    sqlite3PagerUnref(pDbPage);
+  }
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( pBt->autoVacuum ){
+    return ptrmapPut(pBt, pgno, PTRMAP_BTREE, pNewParent->pgno);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+
+
+/*
+** Change the pParent pointer of all children of pPage to point back
+** to pPage.
+**
+** In other words, for every child of pPage, invoke reparentPage()
+** to make sure that each child knows that pPage is its parent.
+**
+** This routine gets called after you memcpy() one page into
+** another.
+*/
+static int reparentChildPages(MemPage *pPage){
+  int i;
+  BtShared *pBt = pPage->pBt;
+  int rc = SQLITE_OK;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( pPage->leaf ) return SQLITE_OK;
+
+  for(i=0; i<pPage->nCell; i++){
+    u8 *pCell = findCell(pPage, i);
+    rc = reparentPage(pBt, get4byte(pCell), pPage, i);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  rc = reparentPage(pBt, get4byte(&pPage->aData[pPage->hdrOffset+8]), 
+                    pPage, i);
+  pPage->idxShift = 0;
+  return rc;
+}
+
+/*
+** Remove the i-th cell from pPage.  This routine effects pPage only.
+** The cell content is not freed or deallocated.  It is assumed that
+** the cell content has been copied someplace else.  This routine just
+** removes the reference to the cell from pPage.
+**
+** "sz" must be the number of bytes in the cell.
+*/
+static void dropCell(MemPage *pPage, int idx, int sz){
+  int i;          /* Loop counter */
+  int pc;         /* Offset to cell content of cell being deleted */
+  u8 *data;       /* pPage->aData */
+  u8 *ptr;        /* Used to move bytes around within data[] */
+
+  assert( idx>=0 && idx<pPage->nCell );
+  assert( sz==cellSize(pPage, idx) );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  data = pPage->aData;
+  ptr = &data[pPage->cellOffset + 2*idx];
+  pc = get2byte(ptr);
+  assert( pc>10 && pc+sz<=pPage->pBt->usableSize );
+  freeSpace(pPage, pc, sz);
+  for(i=idx+1; i<pPage->nCell; i++, ptr+=2){
+    ptr[0] = ptr[2];
+    ptr[1] = ptr[3];
+  }
+  pPage->nCell--;
+  put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
+  pPage->nFree += 2;
+  pPage->idxShift = 1;
+}
+
+/*
+** Insert a new cell on pPage at cell index "i".  pCell points to the
+** content of the cell.
+**
+** If the cell content will fit on the page, then put it there.  If it
+** will not fit, then make a copy of the cell content into pTemp if
+** pTemp is not null.  Regardless of pTemp, allocate a new entry
+** in pPage->aOvfl[] and make it point to the cell content (either
+** in pTemp or the original pCell) and also record its index. 
+** Allocating a new entry in pPage->aCell[] implies that 
+** pPage->nOverflow is incremented.
+**
+** If nSkip is non-zero, then do not copy the first nSkip bytes of the
+** cell. The caller will overwrite them after this function returns. If
+** nSkip is non-zero, then pCell may not point to an invalid memory location 
+** (but pCell+nSkip is always valid).
+*/
+static int insertCell(
+  MemPage *pPage,   /* Page into which we are copying */
+  int i,            /* New cell becomes the i-th cell of the page */
+  u8 *pCell,        /* Content of the new cell */
+  int sz,           /* Bytes of content in pCell */
+  u8 *pTemp,        /* Temp storage space for pCell, if needed */
+  u8 nSkip          /* Do not write the first nSkip bytes of the cell */
+){
+  int idx;          /* Where to write new cell content in data[] */
+  int j;            /* Loop counter */
+  int top;          /* First byte of content for any cell in data[] */
+  int end;          /* First byte past the last cell pointer in data[] */
+  int ins;          /* Index in data[] where new cell pointer is inserted */
+  int hdr;          /* Offset into data[] of the page header */
+  int cellOffset;   /* Address of first cell pointer in data[] */
+  u8 *data;         /* The content of the whole page */
+  u8 *ptr;          /* Used for moving information around in data[] */
+
+  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
+  assert( sz==cellSizePtr(pPage, pCell) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( pPage->nOverflow || sz+2>pPage->nFree ){
+    if( pTemp ){
+      memcpy(pTemp+nSkip, pCell+nSkip, sz-nSkip);
+      pCell = pTemp;
+    }
+    j = pPage->nOverflow++;
+    assert( j<sizeof(pPage->aOvfl)/sizeof(pPage->aOvfl[0]) );
+    pPage->aOvfl[j].pCell = pCell;
+    pPage->aOvfl[j].idx = i;
+    pPage->nFree = 0;
+  }else{
+    int rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+    data = pPage->aData;
+    hdr = pPage->hdrOffset;
+    top = get2byte(&data[hdr+5]);
+    cellOffset = pPage->cellOffset;
+    end = cellOffset + 2*pPage->nCell + 2;
+    ins = cellOffset + 2*i;
+    if( end > top - sz ){
+      rc = defragmentPage(pPage);
+      if( rc!=SQLITE_OK ) return rc;
+      top = get2byte(&data[hdr+5]);
+      assert( end + sz <= top );
+    }
+    idx = allocateSpace(pPage, sz);
+    assert( idx>0 );
+    assert( end <= get2byte(&data[hdr+5]) );
+    pPage->nCell++;
+    pPage->nFree -= 2;
+    memcpy(&data[idx+nSkip], pCell+nSkip, sz-nSkip);
+    for(j=end-2, ptr=&data[j]; j>ins; j-=2, ptr-=2){
+      ptr[0] = ptr[-2];
+      ptr[1] = ptr[-1];
+    }
+    put2byte(&data[ins], idx);
+    put2byte(&data[hdr+3], pPage->nCell);
+    pPage->idxShift = 1;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pPage->pBt->autoVacuum ){
+      /* The cell may contain a pointer to an overflow page. If so, write
+      ** the entry for the overflow page into the pointer map.
+      */
+      CellInfo info;
+      sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+      assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
+      if( (info.nData+(pPage->intKey?0:info.nKey))>info.nLocal ){
+        Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
+        rc = ptrmapPut(pPage->pBt, pgnoOvfl, PTRMAP_OVERFLOW1, pPage->pgno);
+        if( rc!=SQLITE_OK ) return rc;
+      }
+    }
+#endif
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Add a list of cells to a page.  The page should be initially empty.
+** The cells are guaranteed to fit on the page.
+*/
+static void assemblePage(
+  MemPage *pPage,   /* The page to be assemblied */
+  int nCell,        /* The number of cells to add to this page */
+  u8 **apCell,      /* Pointers to cell bodies */
+  u16 *aSize        /* Sizes of the cells */
+){
+  int i;            /* Loop counter */
+  int totalSize;    /* Total size of all cells */
+  int hdr;          /* Index of page header */
+  int cellptr;      /* Address of next cell pointer */
+  int cellbody;     /* Address of next cell body */
+  u8 *data;         /* Data for the page */
+
+  assert( pPage->nOverflow==0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  totalSize = 0;
+  for(i=0; i<nCell; i++){
+    totalSize += aSize[i];
+  }
+  assert( totalSize+2*nCell<=pPage->nFree );
+  assert( pPage->nCell==0 );
+  cellptr = pPage->cellOffset;
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  put2byte(&data[hdr+3], nCell);
+  if( nCell ){
+    cellbody = allocateSpace(pPage, totalSize);
+    assert( cellbody>0 );
+    assert( pPage->nFree >= 2*nCell );
+    pPage->nFree -= 2*nCell;
+    for(i=0; i<nCell; i++){
+      put2byte(&data[cellptr], cellbody);
+      memcpy(&data[cellbody], apCell[i], aSize[i]);
+      cellptr += 2;
+      cellbody += aSize[i];
+    }
+    assert( cellbody==pPage->pBt->usableSize );
+  }
+  pPage->nCell = nCell;
+}
+
+/*
+** The following parameters determine how many adjacent pages get involved
+** in a balancing operation.  NN is the number of neighbors on either side
+** of the page that participate in the balancing operation.  NB is the
+** total number of pages that participate, including the target page and
+** NN neighbors on either side.
+**
+** The minimum value of NN is 1 (of course).  Increasing NN above 1
+** (to 2 or 3) gives a modest improvement in SELECT and DELETE performance
+** in exchange for a larger degradation in INSERT and UPDATE performance.
+** The value of NN appears to give the best results overall.
+*/
+#define NN 1             /* Number of neighbors on either side of pPage */
+#define NB (NN*2+1)      /* Total pages involved in the balance */
+
+/* Forward reference */
+static int balance(MemPage*, int);
+
+#ifndef SQLITE_OMIT_QUICKBALANCE
+/*
+** This version of balance() handles the common special case where
+** a new entry is being inserted on the extreme right-end of the
+** tree, in other words, when the new entry will become the largest
+** entry in the tree.
+**
+** Instead of trying balance the 3 right-most leaf pages, just add
+** a new page to the right-hand side and put the one new entry in
+** that page.  This leaves the right side of the tree somewhat
+** unbalanced.  But odds are that we will be inserting new entries
+** at the end soon afterwards so the nearly empty page will quickly
+** fill up.  On average.
+**
+** pPage is the leaf page which is the right-most page in the tree.
+** pParent is its parent.  pPage must have a single overflow entry
+** which is also the right-most entry on the page.
+*/
+static int balance_quick(MemPage *pPage, MemPage *pParent){
+  int rc;
+  MemPage *pNew;
+  Pgno pgnoNew;
+  u8 *pCell;
+  u16 szCell;
+  CellInfo info;
+  BtShared *pBt = pPage->pBt;
+  int parentIdx = pParent->nCell;   /* pParent new divider cell index */
+  int parentSize;                   /* Size of new divider cell */
+  u8 parentCell[64];                /* Space for the new divider cell */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  /* Allocate a new page. Insert the overflow cell from pPage
+  ** into it. Then remove the overflow cell from pPage.
+  */
+  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pCell = pPage->aOvfl[0].pCell;
+  szCell = cellSizePtr(pPage, pCell);
+  zeroPage(pNew, pPage->aData[0]);
+  assemblePage(pNew, 1, &pCell, &szCell);
+  pPage->nOverflow = 0;
+
+  /* Set the parent of the newly allocated page to pParent. */
+  pNew->pParent = pParent;
+  sqlite3PagerRef(pParent->pDbPage);
+
+  /* pPage is currently the right-child of pParent. Change this
+  ** so that the right-child is the new page allocated above and
+  ** pPage is the next-to-right child. 
+  */
+  assert( pPage->nCell>0 );
+  pCell = findCell(pPage, pPage->nCell-1);
+  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  rc = fillInCell(pParent, parentCell, 0, info.nKey, 0, 0, 0, &parentSize);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( parentSize<64 );
+  rc = insertCell(pParent, parentIdx, parentCell, parentSize, 0, 4);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  put4byte(findOverflowCell(pParent,parentIdx), pPage->pgno);
+  put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* If this is an auto-vacuum database, update the pointer map
+  ** with entries for the new page, and any pointer from the 
+  ** cell on the page to an overflow page.
+  */
+  if( pBt->autoVacuum ){
+    rc = ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno);
+    if( rc==SQLITE_OK ){
+      rc = ptrmapPutOvfl(pNew, 0);
+    }
+    if( rc!=SQLITE_OK ){
+      releasePage(pNew);
+      return rc;
+    }
+  }
+#endif
+
+  /* Release the reference to the new page and balance the parent page,
+  ** in case the divider cell inserted caused it to become overfull.
+  */
+  releasePage(pNew);
+  return balance(pParent, 0);
+}
+#endif /* SQLITE_OMIT_QUICKBALANCE */
+
+/*
+** This routine redistributes Cells on pPage and up to NN*2 siblings
+** of pPage so that all pages have about the same amount of free space.
+** Usually NN siblings on either side of pPage is used in the balancing,
+** though more siblings might come from one side if pPage is the first
+** or last child of its parent.  If pPage has fewer than 2*NN siblings
+** (something which can only happen if pPage is the root page or a 
+** child of root) then all available siblings participate in the balancing.
+**
+** The number of siblings of pPage might be increased or decreased by one or
+** two in an effort to keep pages nearly full but not over full. The root page
+** is special and is allowed to be nearly empty. If pPage is 
+** the root page, then the depth of the tree might be increased
+** or decreased by one, as necessary, to keep the root page from being
+** overfull or completely empty.
+**
+** Note that when this routine is called, some of the Cells on pPage
+** might not actually be stored in pPage->aData[].  This can happen
+** if the page is overfull.  Part of the job of this routine is to
+** make sure all Cells for pPage once again fit in pPage->aData[].
+**
+** In the course of balancing the siblings of pPage, the parent of pPage
+** might become overfull or underfull.  If that happens, then this routine
+** is called recursively on the parent.
+**
+** If this routine fails for any reason, it might leave the database
+** in a corrupted state.  So if this routine fails, the database should
+** be rolled back.
+*/
+static int balance_nonroot(MemPage *pPage){
+  MemPage *pParent;            /* The parent of pPage */
+  BtShared *pBt;               /* The whole database */
+  int nCell = 0;               /* Number of cells in apCell[] */
+  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
+  int nOld;                    /* Number of pages in apOld[] */
+  int nNew;                    /* Number of pages in apNew[] */
+  int nDiv;                    /* Number of cells in apDiv[] */
+  int i, j, k;                 /* Loop counters */
+  int idx;                     /* Index of pPage in pParent->aCell[] */
+  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
+  int rc;                      /* The return code */
+  int leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
+  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
+  int usableSpace;             /* Bytes in pPage beyond the header */
+  int pageFlags;               /* Value of pPage->aData[0] */
+  int subtotal;                /* Subtotal of bytes in cells on one page */
+  int iSpace = 0;              /* First unused byte of aSpace[] */
+  MemPage *apOld[NB];          /* pPage and up to two siblings */
+  Pgno pgnoOld[NB];            /* Page numbers for each page in apOld[] */
+  MemPage *apCopy[NB];         /* Private copies of apOld[] pages */
+  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
+  Pgno pgnoNew[NB+2];          /* Page numbers for each page in apNew[] */
+  u8 *apDiv[NB];               /* Divider cells in pParent */
+  int cntNew[NB+2];            /* Index in aCell[] of cell after i-th page */
+  int szNew[NB+2];             /* Combined size of cells place on i-th page */
+  u8 **apCell = 0;             /* All cells begin balanced */
+  u16 *szCell;                 /* Local size of all cells in apCell[] */
+  u8 *aCopy[NB];               /* Space for holding data of apCopy[] */
+  u8 *aSpace;                  /* Space to hold copies of dividers cells */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  u8 *aFrom = 0;
+#endif
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  /* 
+  ** Find the parent page.
+  */
+  assert( pPage->isInit );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) || pPage->nOverflow==1 );
+  pBt = pPage->pBt;
+  pParent = pPage->pParent;
+  assert( pParent );
+  if( SQLITE_OK!=(rc = sqlite3PagerWrite(pParent->pDbPage)) ){
+    return rc;
+  }
+  TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
+
+#ifndef SQLITE_OMIT_QUICKBALANCE
+  /*
+  ** A special case:  If a new entry has just been inserted into a
+  ** table (that is, a btree with integer keys and all data at the leaves)
+  ** and the new entry is the right-most entry in the tree (it has the
+  ** largest key) then use the special balance_quick() routine for
+  ** balancing.  balance_quick() is much faster and results in a tighter
+  ** packing of data in the common case.
+  */
+  if( pPage->leaf &&
+      pPage->intKey &&
+      pPage->leafData &&
+      pPage->nOverflow==1 &&
+      pPage->aOvfl[0].idx==pPage->nCell &&
+      pPage->pParent->pgno!=1 &&
+      get4byte(&pParent->aData[pParent->hdrOffset+8])==pPage->pgno
+  ){
+    /*
+    ** TODO: Check the siblings to the left of pPage. It may be that
+    ** they are not full and no new page is required.
+    */
+    return balance_quick(pPage, pParent);
+  }
+#endif
+
+  if( SQLITE_OK!=(rc = sqlite3PagerWrite(pPage->pDbPage)) ){
+    return rc;
+  }
+
+  /*
+  ** Find the cell in the parent page whose left child points back
+  ** to pPage.  The "idx" variable is the index of that cell.  If pPage
+  ** is the rightmost child of pParent then set idx to pParent->nCell 
+  */
+  if( pParent->idxShift ){
+    Pgno pgno;
+    pgno = pPage->pgno;
+    assert( pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+    for(idx=0; idx<pParent->nCell; idx++){
+      if( get4byte(findCell(pParent, idx))==pgno ){
+        break;
+      }
+    }
+    assert( idx<pParent->nCell
+             || get4byte(&pParent->aData[pParent->hdrOffset+8])==pgno );
+  }else{
+    idx = pPage->idxParent;
+  }
+
+  /*
+  ** Initialize variables so that it will be safe to jump
+  ** directly to balance_cleanup at any moment.
+  */
+  nOld = nNew = 0;
+  sqlite3PagerRef(pParent->pDbPage);
+
+  /*
+  ** Find sibling pages to pPage and the cells in pParent that divide
+  ** the siblings.  An attempt is made to find NN siblings on either
+  ** side of pPage.  More siblings are taken from one side, however, if
+  ** pPage there are fewer than NN siblings on the other side.  If pParent
+  ** has NB or fewer children then all children of pParent are taken.
+  */
+  nxDiv = idx - NN;
+  if( nxDiv + NB > pParent->nCell ){
+    nxDiv = pParent->nCell - NB + 1;
+  }
+  if( nxDiv<0 ){
+    nxDiv = 0;
+  }
+  nDiv = 0;
+  for(i=0, k=nxDiv; i<NB; i++, k++){
+    if( k<pParent->nCell ){
+      apDiv[i] = findCell(pParent, k);
+      nDiv++;
+      assert( !pParent->leaf );
+      pgnoOld[i] = get4byte(apDiv[i]);
+    }else if( k==pParent->nCell ){
+      pgnoOld[i] = get4byte(&pParent->aData[pParent->hdrOffset+8]);
+    }else{
+      break;
+    }
+    rc = getAndInitPage(pBt, pgnoOld[i], &apOld[i], pParent);
+    if( rc ) goto balance_cleanup;
+    apOld[i]->idxParent = k;
+    apCopy[i] = 0;
+    assert( i==nOld );
+    nOld++;
+    nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
+  }
+
+  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
+  ** alignment */
+  nMaxCells = (nMaxCells + 3)&~3;
+
+  /*
+  ** Allocate space for memory structures
+  */
+  apCell = sqlite3_malloc( 
+       nMaxCells*sizeof(u8*)                       /* apCell */
+     + nMaxCells*sizeof(u16)                       /* szCell */
+     + (ROUND8(sizeof(MemPage))+pBt->pageSize)*NB  /* aCopy */
+     + pBt->pageSize*5                             /* aSpace */
+     + (ISAUTOVACUUM ? nMaxCells : 0)              /* aFrom */
+  );
+  if( apCell==0 ){
+    rc = SQLITE_NOMEM;
+    goto balance_cleanup;
+  }
+  szCell = (u16*)&apCell[nMaxCells];
+  aCopy[0] = (u8*)&szCell[nMaxCells];
+  assert( ((aCopy[0] - (u8*)apCell) & 7)==0 ); /* 8-byte alignment required */
+  for(i=1; i<NB; i++){
+    aCopy[i] = &aCopy[i-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
+    assert( ((aCopy[i] - (u8*)apCell) & 7)==0 ); /* 8-byte alignment required */
+  }
+  aSpace = &aCopy[NB-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
+  assert( ((aSpace - (u8*)apCell) & 7)==0 ); /* 8-byte alignment required */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( pBt->autoVacuum ){
+    aFrom = &aSpace[5*pBt->pageSize];
+  }
+#endif
+  
+  /*
+  ** Make copies of the content of pPage and its siblings into aOld[].
+  ** The rest of this function will use data from the copies rather
+  ** that the original pages since the original pages will be in the
+  ** process of being overwritten.
+  */
+  for(i=0; i<nOld; i++){
+    MemPage *p = apCopy[i] = (MemPage*)aCopy[i];
+    memcpy(p, apOld[i], sizeof(MemPage));
+    p->aData = (void*)&p[1];
+    memcpy(p->aData, apOld[i]->aData, pBt->pageSize);
+  }
+
+  /*
+  ** Load pointers to all cells on sibling pages and the divider cells
+  ** into the local apCell[] array.  Make copies of the divider cells
+  ** into space obtained form aSpace[] and remove the the divider Cells
+  ** from pParent.
+  **
+  ** If the siblings are on leaf pages, then the child pointers of the
+  ** divider cells are stripped from the cells before they are copied
+  ** into aSpace[].  In this way, all cells in apCell[] are without
+  ** child pointers.  If siblings are not leaves, then all cell in
+  ** apCell[] include child pointers.  Either way, all cells in apCell[]
+  ** are alike.
+  **
+  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
+  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
+  */
+  nCell = 0;
+  leafCorrection = pPage->leaf*4;
+  leafData = pPage->leafData && pPage->leaf;
+  for(i=0; i<nOld; i++){
+    MemPage *pOld = apCopy[i];
+    int limit = pOld->nCell+pOld->nOverflow;
+    for(j=0; j<limit; j++){
+      assert( nCell<nMaxCells );
+      apCell[nCell] = findOverflowCell(pOld, j);
+      szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        int a;
+        aFrom[nCell] = i;
+        for(a=0; a<pOld->nOverflow; a++){
+          if( pOld->aOvfl[a].pCell==apCell[nCell] ){
+            aFrom[nCell] = 0xFF;
+            break;
+          }
+        }
+      }
+#endif
+      nCell++;
+    }
+    if( i<nOld-1 ){
+      u16 sz = cellSizePtr(pParent, apDiv[i]);
+      if( leafData ){
+        /* With the LEAFDATA flag, pParent cells hold only INTKEYs that
+        ** are duplicates of keys on the child pages.  We need to remove
+        ** the divider cells from pParent, but the dividers cells are not
+        ** added to apCell[] because they are duplicates of child cells.
+        */
+        dropCell(pParent, nxDiv, sz);
+      }else{
+        u8 *pTemp;
+        assert( nCell<nMaxCells );
+        szCell[nCell] = sz;
+        pTemp = &aSpace[iSpace];
+        iSpace += sz;
+        assert( iSpace<=pBt->pageSize*5 );
+        memcpy(pTemp, apDiv[i], sz);
+        apCell[nCell] = pTemp+leafCorrection;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+        if( pBt->autoVacuum ){
+          aFrom[nCell] = 0xFF;
+        }
+#endif
+        dropCell(pParent, nxDiv, sz);
+        szCell[nCell] -= leafCorrection;
+        assert( get4byte(pTemp)==pgnoOld[i] );
+        if( !pOld->leaf ){
+          assert( leafCorrection==0 );
+          /* The right pointer of the child page pOld becomes the left
+          ** pointer of the divider cell */
+          memcpy(apCell[nCell], &pOld->aData[pOld->hdrOffset+8], 4);
+        }else{
+          assert( leafCorrection==4 );
+          if( szCell[nCell]<4 ){
+            /* Do not allow any cells smaller than 4 bytes. */
+            szCell[nCell] = 4;
+          }
+        }
+        nCell++;
+      }
+    }
+  }
+
+  /*
+  ** Figure out the number of pages needed to hold all nCell cells.
+  ** Store this number in "k".  Also compute szNew[] which is the total
+  ** size of all cells on the i-th page and cntNew[] which is the index
+  ** in apCell[] of the cell that divides page i from page i+1.  
+  ** cntNew[k] should equal nCell.
+  **
+  ** Values computed by this block:
+  **
+  **           k: The total number of sibling pages
+  **    szNew[i]: Spaced used on the i-th sibling page.
+  **   cntNew[i]: Index in apCell[] and szCell[] for the first cell to
+  **              the right of the i-th sibling page.
+  ** usableSpace: Number of bytes of space available on each sibling.
+  ** 
+  */
+  usableSpace = pBt->usableSize - 12 + leafCorrection;
+  for(subtotal=k=i=0; i<nCell; i++){
+    assert( i<nMaxCells );
+    subtotal += szCell[i] + 2;
+    if( subtotal > usableSpace ){
+      szNew[k] = subtotal - szCell[i];
+      cntNew[k] = i;
+      if( leafData ){ i--; }
+      subtotal = 0;
+      k++;
+    }
+  }
+  szNew[k] = subtotal;
+  cntNew[k] = nCell;
+  k++;
+
+  /*
+  ** The packing computed by the previous block is biased toward the siblings
+  ** on the left side.  The left siblings are always nearly full, while the
+  ** right-most sibling might be nearly empty.  This block of code attempts
+  ** to adjust the packing of siblings to get a better balance.
+  **
+  ** This adjustment is more than an optimization.  The packing above might
+  ** be so out of balance as to be illegal.  For example, the right-most
+  ** sibling might be completely empty.  This adjustment is not optional.
+  */
+  for(i=k-1; i>0; i--){
+    int szRight = szNew[i];  /* Size of sibling on the right */
+    int szLeft = szNew[i-1]; /* Size of sibling on the left */
+    int r;              /* Index of right-most cell in left sibling */
+    int d;              /* Index of first cell to the left of right sibling */
+
+    r = cntNew[i-1] - 1;
+    d = r + 1 - leafData;
+    assert( d<nMaxCells );
+    assert( r<nMaxCells );
+    while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){
+      szRight += szCell[d] + 2;
+      szLeft -= szCell[r] + 2;
+      cntNew[i-1]--;
+      r = cntNew[i-1] - 1;
+      d = r + 1 - leafData;
+    }
+    szNew[i] = szRight;
+    szNew[i-1] = szLeft;
+  }
+
+  /* Either we found one or more cells (cntnew[0])>0) or we are the
+  ** a virtual root page.  A virtual root page is when the real root
+  ** page is page 1 and we are the only child of that page.
+  */
+  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) );
+
+  /*
+  ** Allocate k new pages.  Reuse old pages where possible.
+  */
+  assert( pPage->pgno>1 );
+  pageFlags = pPage->aData[0];
+  for(i=0; i<k; i++){
+    MemPage *pNew;
+    if( i<nOld ){
+      pNew = apNew[i] = apOld[i];
+      pgnoNew[i] = pgnoOld[i];
+      apOld[i] = 0;
+      rc = sqlite3PagerWrite(pNew->pDbPage);
+      nNew++;
+      if( rc ) goto balance_cleanup;
+    }else{
+      assert( i>0 );
+      rc = allocateBtreePage(pBt, &pNew, &pgnoNew[i], pgnoNew[i-1], 0);
+      if( rc ) goto balance_cleanup;
+      apNew[i] = pNew;
+      nNew++;
+    }
+    zeroPage(pNew, pageFlags);
+  }
+
+  /* Free any old pages that were not reused as new pages.
+  */
+  while( i<nOld ){
+    rc = freePage(apOld[i]);
+    if( rc ) goto balance_cleanup;
+    releasePage(apOld[i]);
+    apOld[i] = 0;
+    i++;
+  }
+
+  /*
+  ** Put the new pages in accending order.  This helps to
+  ** keep entries in the disk file in order so that a scan
+  ** of the table is a linear scan through the file.  That
+  ** in turn helps the operating system to deliver pages
+  ** from the disk more rapidly.
+  **
+  ** An O(n^2) insertion sort algorithm is used, but since
+  ** n is never more than NB (a small constant), that should
+  ** not be a problem.
+  **
+  ** When NB==3, this one optimization makes the database
+  ** about 25% faster for large insertions and deletions.
+  */
+  for(i=0; i<k-1; i++){
+    int minV = pgnoNew[i];
+    int minI = i;
+    for(j=i+1; j<k; j++){
+      if( pgnoNew[j]<(unsigned)minV ){
+        minI = j;
+        minV = pgnoNew[j];
+      }
+    }
+    if( minI>i ){
+      int t;
+      MemPage *pT;
+      t = pgnoNew[i];
+      pT = apNew[i];
+      pgnoNew[i] = pgnoNew[minI];
+      apNew[i] = apNew[minI];
+      pgnoNew[minI] = t;
+      apNew[minI] = pT;
+    }
+  }
+  TRACE(("BALANCE: old: %d %d %d  new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
+    pgnoOld[0], 
+    nOld>=2 ? pgnoOld[1] : 0,
+    nOld>=3 ? pgnoOld[2] : 0,
+    pgnoNew[0], szNew[0],
+    nNew>=2 ? pgnoNew[1] : 0, nNew>=2 ? szNew[1] : 0,
+    nNew>=3 ? pgnoNew[2] : 0, nNew>=3 ? szNew[2] : 0,
+    nNew>=4 ? pgnoNew[3] : 0, nNew>=4 ? szNew[3] : 0,
+    nNew>=5 ? pgnoNew[4] : 0, nNew>=5 ? szNew[4] : 0));
+
+  /*
+  ** Evenly distribute the data in apCell[] across the new pages.
+  ** Insert divider cells into pParent as necessary.
+  */
+  j = 0;
+  for(i=0; i<nNew; i++){
+    /* Assemble the new sibling page. */
+    MemPage *pNew = apNew[i];
+    assert( j<nMaxCells );
+    assert( pNew->pgno==pgnoNew[i] );
+    assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
+    assert( pNew->nCell>0 || (nNew==1 && cntNew[0]==0) );
+    assert( pNew->nOverflow==0 );
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    /* If this is an auto-vacuum database, update the pointer map entries
+    ** that point to the siblings that were rearranged. These can be: left
+    ** children of cells, the right-child of the page, or overflow pages
+    ** pointed to by cells.
+    */
+    if( pBt->autoVacuum ){
+      for(k=j; k<cntNew[i]; k++){
+        assert( k<nMaxCells );
+        if( aFrom[k]==0xFF || apCopy[aFrom[k]]->pgno!=pNew->pgno ){
+          rc = ptrmapPutOvfl(pNew, k-j);
+          if( rc!=SQLITE_OK ){
+            goto balance_cleanup;
+          }
+        }
+      }
+    }
+#endif
+
+    j = cntNew[i];
+
+    /* If the sibling page assembled above was not the right-most sibling,
+    ** insert a divider cell into the parent page.
+    */
+    if( i<nNew-1 && j<nCell ){
+      u8 *pCell;
+      u8 *pTemp;
+      int sz;
+
+      assert( j<nMaxCells );
+      pCell = apCell[j];
+      sz = szCell[j] + leafCorrection;
+      if( !pNew->leaf ){
+        memcpy(&pNew->aData[8], pCell, 4);
+        pTemp = 0;
+      }else if( leafData ){
+        /* If the tree is a leaf-data tree, and the siblings are leaves, 
+        ** then there is no divider cell in apCell[]. Instead, the divider 
+        ** cell consists of the integer key for the right-most cell of 
+        ** the sibling-page assembled above only.
+        */
+        CellInfo info;
+        j--;
+        sqlite3BtreeParseCellPtr(pNew, apCell[j], &info);
+        pCell = &aSpace[iSpace];
+        fillInCell(pParent, pCell, 0, info.nKey, 0, 0, 0, &sz);
+        iSpace += sz;
+        assert( iSpace<=pBt->pageSize*5 );
+        pTemp = 0;
+      }else{
+        pCell -= 4;
+        pTemp = &aSpace[iSpace];
+        iSpace += sz;
+        assert( iSpace<=pBt->pageSize*5 );
+        /* Obscure case for non-leaf-data trees: If the cell at pCell was
+        ** previously stored on a leaf node, and its reported size was 4
+        ** bytes, then it may actually be smaller than this 
+        ** (see sqlite3BtreeParseCellPtr(), 4 bytes is the minimum size of
+        ** any cell). But it is important to pass the correct size to 
+        ** insertCell(), so reparse the cell now.
+        **
+        ** Note that this can never happen in an SQLite data file, as all
+        ** cells are at least 4 bytes. It only happens in b-trees used
+        ** to evaluate "IN (SELECT ...)" and similar clauses.
+        */
+        if( szCell[j]==4 ){
+          assert(leafCorrection==4);
+          sz = cellSizePtr(pParent, pCell);
+        }
+      }
+      rc = insertCell(pParent, nxDiv, pCell, sz, pTemp, 4);
+      if( rc!=SQLITE_OK ) goto balance_cleanup;
+      put4byte(findOverflowCell(pParent,nxDiv), pNew->pgno);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If this is an auto-vacuum database, and not a leaf-data tree,
+      ** then update the pointer map with an entry for the overflow page
+      ** that the cell just inserted points to (if any).
+      */
+      if( pBt->autoVacuum && !leafData ){
+        rc = ptrmapPutOvfl(pParent, nxDiv);
+        if( rc!=SQLITE_OK ){
+          goto balance_cleanup;
+        }
+      }
+#endif
+      j++;
+      nxDiv++;
+    }
+  }
+  assert( j==nCell );
+  assert( nOld>0 );
+  assert( nNew>0 );
+  if( (pageFlags & PTF_LEAF)==0 ){
+    memcpy(&apNew[nNew-1]->aData[8], &apCopy[nOld-1]->aData[8], 4);
+  }
+  if( nxDiv==pParent->nCell+pParent->nOverflow ){
+    /* Right-most sibling is the right-most child of pParent */
+    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew[nNew-1]);
+  }else{
+    /* Right-most sibling is the left child of the first entry in pParent
+    ** past the right-most divider entry */
+    put4byte(findOverflowCell(pParent, nxDiv), pgnoNew[nNew-1]);
+  }
+
+  /*
+  ** Reparent children of all cells.
+  */
+  for(i=0; i<nNew; i++){
+    rc = reparentChildPages(apNew[i]);
+    if( rc!=SQLITE_OK ) goto balance_cleanup;
+  }
+  rc = reparentChildPages(pParent);
+  if( rc!=SQLITE_OK ) goto balance_cleanup;
+
+  /*
+  ** Balance the parent page.  Note that the current page (pPage) might
+  ** have been added to the freelist so it might no longer be initialized.
+  ** But the parent page will always be initialized.
+  */
+  assert( pParent->isInit );
+  rc = balance(pParent, 0);
+  
+  /*
+  ** Cleanup before returning.
+  */
+balance_cleanup:
+  sqlite3_free(apCell);
+  for(i=0; i<nOld; i++){
+    releasePage(apOld[i]);
+  }
+  for(i=0; i<nNew; i++){
+    releasePage(apNew[i]);
+  }
+  releasePage(pParent);
+  TRACE(("BALANCE: finished with %d: old=%d new=%d cells=%d\n",
+          pPage->pgno, nOld, nNew, nCell));
+  return rc;
+}
+
+/*
+** This routine is called for the root page of a btree when the root
+** page contains no cells.  This is an opportunity to make the tree
+** shallower by one level.
+*/
+static int balance_shallower(MemPage *pPage){
+  MemPage *pChild;             /* The only child page of pPage */
+  Pgno pgnoChild;              /* Page number for pChild */
+  int rc = SQLITE_OK;          /* Return code from subprocedures */
+  BtShared *pBt;                  /* The main BTree structure */
+  int mxCellPerPage;           /* Maximum number of cells per page */
+  u8 **apCell;                 /* All cells from pages being balanced */
+  u16 *szCell;                 /* Local size of all cells */
+
+  assert( pPage->pParent==0 );
+  assert( pPage->nCell==0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pBt = pPage->pBt;
+  mxCellPerPage = MX_CELL(pBt);
+  apCell = sqlite3_malloc( mxCellPerPage*(sizeof(u8*)+sizeof(u16)) );
+  if( apCell==0 ) return SQLITE_NOMEM;
+  szCell = (u16*)&apCell[mxCellPerPage];
+  if( pPage->leaf ){
+    /* The table is completely empty */
+    TRACE(("BALANCE: empty table %d\n", pPage->pgno));
+  }else{
+    /* The root page is empty but has one child.  Transfer the
+    ** information from that one child into the root page if it 
+    ** will fit.  This reduces the depth of the tree by one.
+    **
+    ** If the root page is page 1, it has less space available than
+    ** its child (due to the 100 byte header that occurs at the beginning
+    ** of the database fle), so it might not be able to hold all of the 
+    ** information currently contained in the child.  If this is the 
+    ** case, then do not do the transfer.  Leave page 1 empty except
+    ** for the right-pointer to the child page.  The child page becomes
+    ** the virtual root of the tree.
+    */
+    pgnoChild = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    assert( pgnoChild>0 );
+    assert( pgnoChild<=sqlite3PagerPagecount(pPage->pBt->pPager) );
+    rc = sqlite3BtreeGetPage(pPage->pBt, pgnoChild, &pChild, 0);
+    if( rc ) goto end_shallow_balance;
+    if( pPage->pgno==1 ){
+      rc = sqlite3BtreeInitPage(pChild, pPage);
+      if( rc ) goto end_shallow_balance;
+      assert( pChild->nOverflow==0 );
+      if( pChild->nFree>=100 ){
+        /* The child information will fit on the root page, so do the
+        ** copy */
+        int i;
+        zeroPage(pPage, pChild->aData[0]);
+        for(i=0; i<pChild->nCell; i++){
+          apCell[i] = findCell(pChild,i);
+          szCell[i] = cellSizePtr(pChild, apCell[i]);
+        }
+        assemblePage(pPage, pChild->nCell, apCell, szCell);
+        /* Copy the right-pointer of the child to the parent. */
+        put4byte(&pPage->aData[pPage->hdrOffset+8], 
+            get4byte(&pChild->aData[pChild->hdrOffset+8]));
+        freePage(pChild);
+        TRACE(("BALANCE: child %d transfer to page 1\n", pChild->pgno));
+      }else{
+        /* The child has more information that will fit on the root.
+        ** The tree is already balanced.  Do nothing. */
+        TRACE(("BALANCE: child %d will not fit on page 1\n", pChild->pgno));
+      }
+    }else{
+      memcpy(pPage->aData, pChild->aData, pPage->pBt->usableSize);
+      pPage->isInit = 0;
+      pPage->pParent = 0;
+      rc = sqlite3BtreeInitPage(pPage, 0);
+      assert( rc==SQLITE_OK );
+      freePage(pChild);
+      TRACE(("BALANCE: transfer child %d into root %d\n",
+              pChild->pgno, pPage->pgno));
+    }
+    rc = reparentChildPages(pPage);
+    assert( pPage->nOverflow==0 );
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      int i;
+      for(i=0; i<pPage->nCell; i++){ 
+        rc = ptrmapPutOvfl(pPage, i);
+        if( rc!=SQLITE_OK ){
+          goto end_shallow_balance;
+        }
+      }
+    }
+#endif
+    releasePage(pChild);
+  }
+end_shallow_balance:
+  sqlite3_free(apCell);
+  return rc;
+}
+
+
+/*
+** The root page is overfull
+**
+** When this happens, Create a new child page and copy the
+** contents of the root into the child.  Then make the root
+** page an empty page with rightChild pointing to the new
+** child.   Finally, call balance_internal() on the new child
+** to cause it to split.
+*/
+static int balance_deeper(MemPage *pPage){
+  int rc;             /* Return value from subprocedures */
+  MemPage *pChild;    /* Pointer to a new child page */
+  Pgno pgnoChild;     /* Page number of the new child page */
+  BtShared *pBt;         /* The BTree */
+  int usableSize;     /* Total usable size of a page */
+  u8 *data;           /* Content of the parent page */
+  u8 *cdata;          /* Content of the child page */
+  int hdr;            /* Offset to page header in parent */
+  int brk;            /* Offset to content of first cell in parent */
+
+  assert( pPage->pParent==0 );
+  assert( pPage->nOverflow>0 );
+  pBt = pPage->pBt;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  rc = allocateBtreePage(pBt, &pChild, &pgnoChild, pPage->pgno, 0);
+  if( rc ) return rc;
+  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
+  usableSize = pBt->usableSize;
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  brk = get2byte(&data[hdr+5]);
+  cdata = pChild->aData;
+  memcpy(cdata, &data[hdr], pPage->cellOffset+2*pPage->nCell-hdr);
+  memcpy(&cdata[brk], &data[brk], usableSize-brk);
+  assert( pChild->isInit==0 );
+  rc = sqlite3BtreeInitPage(pChild, pPage);
+  if( rc ) goto balancedeeper_out;
+  memcpy(pChild->aOvfl, pPage->aOvfl, pPage->nOverflow*sizeof(pPage->aOvfl[0]));
+  pChild->nOverflow = pPage->nOverflow;
+  if( pChild->nOverflow ){
+    pChild->nFree = 0;
+  }
+  assert( pChild->nCell==pPage->nCell );
+  zeroPage(pPage, pChild->aData[0] & ~PTF_LEAF);
+  put4byte(&pPage->aData[pPage->hdrOffset+8], pgnoChild);
+  TRACE(("BALANCE: copy root %d into %d\n", pPage->pgno, pChild->pgno));
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( pBt->autoVacuum ){
+    int i;
+    rc = ptrmapPut(pBt, pChild->pgno, PTRMAP_BTREE, pPage->pgno);
+    if( rc ) goto balancedeeper_out;
+    for(i=0; i<pChild->nCell; i++){
+      rc = ptrmapPutOvfl(pChild, i);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+#endif
+  rc = balance_nonroot(pChild);
+
+balancedeeper_out:
+  releasePage(pChild);
+  return rc;
+}
+
+/*
+** Decide if the page pPage needs to be balanced.  If balancing is
+** required, call the appropriate balancing routine.
+*/
+static int balance(MemPage *pPage, int insert){
+  int rc = SQLITE_OK;
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  if( pPage->pParent==0 ){
+    rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc==SQLITE_OK && pPage->nOverflow>0 ){
+      rc = balance_deeper(pPage);
+    }
+    if( rc==SQLITE_OK && pPage->nCell==0 ){
+      rc = balance_shallower(pPage);
+    }
+  }else{
+    if( pPage->nOverflow>0 || 
+        (!insert && pPage->nFree>pPage->pBt->usableSize*2/3) ){
+      rc = balance_nonroot(pPage);
+    }
+  }
+  return rc;
+}
+
+/*
+** This routine checks all cursors that point to table pgnoRoot.
+** If any of those cursors were opened with wrFlag==0 in a different
+** database connection (a database connection that shares the pager
+** cache with the current connection) and that other connection 
+** is not in the ReadUncommmitted state, then this routine returns 
+** SQLITE_LOCKED.
+**
+** In addition to checking for read-locks (where a read-lock 
+** means a cursor opened with wrFlag==0) this routine also moves
+** all write cursors so that they are pointing to the 
+** first Cell on the root page.  This is necessary because an insert 
+** or delete might change the number of cells on a page or delete
+** a page entirely and we do not want to leave any cursors 
+** pointing to non-existant pages or cells.
+*/
+static int checkReadLocks(Btree *pBtree, Pgno pgnoRoot, BtCursor *pExclude){
+  BtCursor *p;
+  BtShared *pBt = pBtree->pBt;
+  sqlite3 *db = pBtree->db;
+  assert( sqlite3BtreeHoldsMutex(pBtree) );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    if( p==pExclude ) continue;
+    if( p->eState!=CURSOR_VALID ) continue;
+    if( p->pgnoRoot!=pgnoRoot ) continue;
+    if( p->wrFlag==0 ){
+      sqlite3 *dbOther = p->pBtree->db;
+      if( dbOther==0 ||
+         (dbOther!=db && (dbOther->flags & SQLITE_ReadUncommitted)==0) ){
+        return SQLITE_LOCKED;
+      }
+    }else if( p->pPage->pgno!=p->pgnoRoot ){
+      moveToRoot(p);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Make sure pBt->pTmpSpace points to an allocation of 
+** MX_CELL_SIZE(pBt) bytes.
+*/
+static void allocateTempSpace(BtShared *pBt){
+  if( !pBt->pTmpSpace ){
+    pBt->pTmpSpace = sqlite3_malloc(MX_CELL_SIZE(pBt));
+  }
+}
+
+/*
+** Insert a new record into the BTree.  The key is given by (pKey,nKey)
+** and the data is given by (pData,nData).  The cursor is used only to
+** define what table the record should be inserted into.  The cursor
+** is left pointing at a random location.
+**
+** For an INTKEY table, only the nKey value of the key is used.  pKey is
+** ignored.  For a ZERODATA table, the pData and nData are both ignored.
+*/
+SQLITE_PRIVATE int sqlite3BtreeInsert(
+  BtCursor *pCur,                /* Insert data into the table of this cursor */
+  const void *pKey, i64 nKey,    /* The key of the new record */
+  const void *pData, int nData,  /* The data of the new record */
+  int nZero,                     /* Number of extra 0 bytes to append to data */
+  int appendBias                 /* True if this is likely an append */
+){
+  int rc;
+  int loc;
+  int szNew;
+  MemPage *pPage;
+  Btree *p = pCur->pBtree;
+  BtShared *pBt = p->pBt;
+  unsigned char *oldCell;
+  unsigned char *newCell = 0;
+
+  assert( cursorHoldsMutex(pCur) );
+  if( pBt->inTransaction!=TRANS_WRITE ){
+    /* Must start a transaction before doing an insert */
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+    return rc;
+  }
+  assert( !pBt->readOnly );
+  if( !pCur->wrFlag ){
+    return SQLITE_PERM;   /* Cursor not open for writing */
+  }
+  if( checkReadLocks(pCur->pBtree, pCur->pgnoRoot, pCur) ){
+    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
+  }
+  if( pCur->eState==CURSOR_FAULT ){
+    return pCur->skip;
+  }
+
+  /* Save the positions of any other cursors open on this table */
+  clearCursorPosition(pCur);
+  if( 
+    SQLITE_OK!=(rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur)) ||
+    SQLITE_OK!=(rc = sqlite3BtreeMoveto(pCur, pKey, 0, nKey, appendBias, &loc))
+  ){
+    return rc;
+  }
+
+  pPage = pCur->pPage;
+  assert( pPage->intKey || nKey>=0 );
+  assert( pPage->leaf || !pPage->leafData );
+  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
+          pCur->pgnoRoot, nKey, nData, pPage->pgno,
+          loc==0 ? "overwrite" : "new entry"));
+  assert( pPage->isInit );
+  allocateTempSpace(pBt);
+  newCell = pBt->pTmpSpace;
+  if( newCell==0 ) return SQLITE_NOMEM;
+  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
+  if( rc ) goto end_insert;
+  assert( szNew==cellSizePtr(pPage, newCell) );
+  assert( szNew<=MX_CELL_SIZE(pBt) );
+  if( loc==0 && CURSOR_VALID==pCur->eState ){
+    u16 szOld;
+    assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
+    rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc ){
+      goto end_insert;
+    }
+    oldCell = findCell(pPage, pCur->idx);
+    if( !pPage->leaf ){
+      memcpy(newCell, oldCell, 4);
+    }
+    szOld = cellSizePtr(pPage, oldCell);
+    rc = clearCell(pPage, oldCell);
+    if( rc ) goto end_insert;
+    dropCell(pPage, pCur->idx, szOld);
+  }else if( loc<0 && pPage->nCell>0 ){
+    assert( pPage->leaf );
+    pCur->idx++;
+    pCur->info.nSize = 0;
+    pCur->validNKey = 0;
+  }else{
+    assert( pPage->leaf );
+  }
+  rc = insertCell(pPage, pCur->idx, newCell, szNew, 0, 0);
+  if( rc!=SQLITE_OK ) goto end_insert;
+  rc = balance(pPage, 1);
+  /* sqlite3BtreePageDump(pCur->pBt, pCur->pgnoRoot, 1); */
+  /* fflush(stdout); */
+  if( rc==SQLITE_OK ){
+    moveToRoot(pCur);
+  }
+end_insert:
+  return rc;
+}
+
+/*
+** Delete the entry that the cursor is pointing to.  The cursor
+** is left pointing at a random location.
+*/
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur){
+  MemPage *pPage = pCur->pPage;
+  unsigned char *pCell;
+  int rc;
+  Pgno pgnoChild = 0;
+  Btree *p = pCur->pBtree;
+  BtShared *pBt = p->pBt;
+
+  assert( cursorHoldsMutex(pCur) );
+  assert( pPage->isInit );
+  if( pBt->inTransaction!=TRANS_WRITE ){
+    /* Must start a transaction before doing a delete */
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+    return rc;
+  }
+  assert( !pBt->readOnly );
+  if( pCur->eState==CURSOR_FAULT ){
+    return pCur->skip;
+  }
+  if( pCur->idx >= pPage->nCell ){
+    return SQLITE_ERROR;  /* The cursor is not pointing to anything */
+  }
+  if( !pCur->wrFlag ){
+    return SQLITE_PERM;   /* Did not open this cursor for writing */
+  }
+  if( checkReadLocks(pCur->pBtree, pCur->pgnoRoot, pCur) ){
+    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
+  }
+
+  /* Restore the current cursor position (a no-op if the cursor is not in 
+  ** CURSOR_REQUIRESEEK state) and save the positions of any other cursors 
+  ** open on the same table. Then call sqlite3PagerWrite() on the page
+  ** that the entry will be deleted from.
+  */
+  if( 
+    (rc = restoreOrClearCursorPosition(pCur))!=0 ||
+    (rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur))!=0 ||
+    (rc = sqlite3PagerWrite(pPage->pDbPage))!=0
+  ){
+    return rc;
+  }
+
+  /* Locate the cell within its page and leave pCell pointing to the
+  ** data. The clearCell() call frees any overflow pages associated with the
+  ** cell. The cell itself is still intact.
+  */
+  pCell = findCell(pPage, pCur->idx);
+  if( !pPage->leaf ){
+    pgnoChild = get4byte(pCell);
+  }
+  rc = clearCell(pPage, pCell);
+  if( rc ){
+    return rc;
+  }
+
+  if( !pPage->leaf ){
+    /*
+    ** The entry we are about to delete is not a leaf so if we do not
+    ** do something we will leave a hole on an internal page.
+    ** We have to fill the hole by moving in a cell from a leaf.  The
+    ** next Cell after the one to be deleted is guaranteed to exist and
+    ** to be a leaf so we can use it.
+    */
+    BtCursor leafCur;
+    unsigned char *pNext;
+    int notUsed;
+    unsigned char *tempCell = 0;
+    assert( !pPage->leafData );
+    sqlite3BtreeGetTempCursor(pCur, &leafCur);
+    rc = sqlite3BtreeNext(&leafCur, &notUsed);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3PagerWrite(leafCur.pPage->pDbPage);
+    }
+    if( rc==SQLITE_OK ){
+      u16 szNext;
+      TRACE(("DELETE: table=%d delete internal from %d replace from leaf %d\n",
+         pCur->pgnoRoot, pPage->pgno, leafCur.pPage->pgno));
+      dropCell(pPage, pCur->idx, cellSizePtr(pPage, pCell));
+      pNext = findCell(leafCur.pPage, leafCur.idx);
+      szNext = cellSizePtr(leafCur.pPage, pNext);
+      assert( MX_CELL_SIZE(pBt)>=szNext+4 );
+      allocateTempSpace(pBt);
+      tempCell = pBt->pTmpSpace;
+      if( tempCell==0 ){
+        rc = SQLITE_NOMEM;
+      }
+      if( rc==SQLITE_OK ){
+        rc = insertCell(pPage, pCur->idx, pNext-4, szNext+4, tempCell, 0);
+      }
+      if( rc==SQLITE_OK ){
+        put4byte(findOverflowCell(pPage, pCur->idx), pgnoChild);
+        rc = balance(pPage, 0);
+      }
+      if( rc==SQLITE_OK ){
+        dropCell(leafCur.pPage, leafCur.idx, szNext);
+        rc = balance(leafCur.pPage, 0);
+      }
+    }
+    sqlite3BtreeReleaseTempCursor(&leafCur);
+  }else{
+    TRACE(("DELETE: table=%d delete from leaf %d\n",
+       pCur->pgnoRoot, pPage->pgno));
+    dropCell(pPage, pCur->idx, cellSizePtr(pPage, pCell));
+    rc = balance(pPage, 0);
+  }
+  if( rc==SQLITE_OK ){
+    moveToRoot(pCur);
+  }
+  return rc;
+}
+
+/*
+** Create a new BTree table.  Write into *piTable the page
+** number for the root page of the new table.
+**
+** The type of type is determined by the flags parameter.  Only the
+** following values of flags are currently in use.  Other values for
+** flags might not work:
+**
+**     BTREE_INTKEY|BTREE_LEAFDATA     Used for SQL tables with rowid keys
+**     BTREE_ZERODATA                  Used for SQL indices
+*/
+static int btreeCreateTable(Btree *p, int *piTable, int flags){
+  BtShared *pBt = p->pBt;
+  MemPage *pRoot;
+  Pgno pgnoRoot;
+  int rc;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  if( pBt->inTransaction!=TRANS_WRITE ){
+    /* Must start a transaction first */
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+    return rc;
+  }
+  assert( !pBt->readOnly );
+
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+  if( rc ){
+    return rc;
+  }
+#else
+  if( pBt->autoVacuum ){
+    Pgno pgnoMove;      /* Move a page here to make room for the root-page */
+    MemPage *pPageMove; /* The page to move to. */
+
+    /* Creating a new table may probably require moving an existing database
+    ** to make room for the new tables root page. In case this page turns
+    ** out to be an overflow page, delete all overflow page-map caches
+    ** held by open cursors.
+    */
+    invalidateAllOverflowCache(pBt);
+
+    /* Read the value of meta[3] from the database to determine where the
+    ** root page of the new table should go. meta[3] is the largest root-page
+    ** created so far, so the new root-page is (meta[3]+1).
+    */
+    rc = sqlite3BtreeGetMeta(p, 4, &pgnoRoot);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    pgnoRoot++;
+
+    /* The new root-page may not be allocated on a pointer-map page, or the
+    ** PENDING_BYTE page.
+    */
+    while( pgnoRoot==PTRMAP_PAGENO(pBt, pgnoRoot) ||
+        pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
+      pgnoRoot++;
+    }
+    assert( pgnoRoot>=3 );
+
+    /* Allocate a page. The page that currently resides at pgnoRoot will
+    ** be moved to the allocated page (unless the allocated page happens
+    ** to reside at pgnoRoot).
+    */
+    rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, 1);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    if( pgnoMove!=pgnoRoot ){
+      /* pgnoRoot is the page that will be used for the root-page of
+      ** the new table (assuming an error did not occur). But we were
+      ** allocated pgnoMove. If required (i.e. if it was not allocated
+      ** by extending the file), the current page at position pgnoMove
+      ** is already journaled.
+      */
+      u8 eType;
+      Pgno iPtrPage;
+
+      releasePage(pPageMove);
+
+      /* Move the page currently at pgnoRoot to pgnoMove. */
+      rc = sqlite3BtreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
+      if( rc!=SQLITE_OK || eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
+        releasePage(pRoot);
+        return rc;
+      }
+      assert( eType!=PTRMAP_ROOTPAGE );
+      assert( eType!=PTRMAP_FREEPAGE );
+      rc = sqlite3PagerWrite(pRoot->pDbPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove);
+      releasePage(pRoot);
+
+      /* Obtain the page at pgnoRoot */
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = sqlite3BtreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = sqlite3PagerWrite(pRoot->pDbPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+    }else{
+      pRoot = pPageMove;
+    } 
+
+    /* Update the pointer-map and meta-data with the new root-page number. */
+    rc = ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0);
+    if( rc ){
+      releasePage(pRoot);
+      return rc;
+    }
+    rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
+    if( rc ){
+      releasePage(pRoot);
+      return rc;
+    }
+
+  }else{
+    rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+    if( rc ) return rc;
+  }
+#endif
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  zeroPage(pRoot, flags | PTF_LEAF);
+  sqlite3PagerUnref(pRoot->pDbPage);
+  *piTable = (int)pgnoRoot;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, int *piTable, int flags){
+  int rc;
+  sqlite3BtreeEnter(p);
+  p->pBt->db = p->db;
+  rc = btreeCreateTable(p, piTable, flags);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Erase the given database page and all its children.  Return
+** the page to the freelist.
+*/
+static int clearDatabasePage(
+  BtShared *pBt,           /* The BTree that contains the table */
+  Pgno pgno,            /* Page number to clear */
+  MemPage *pParent,     /* Parent page.  NULL for the root */
+  int freePageFlag      /* Deallocate page if true */
+){
+  MemPage *pPage = 0;
+  int rc;
+  unsigned char *pCell;
+  int i;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno>sqlite3PagerPagecount(pBt->pPager) ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+
+  rc = getAndInitPage(pBt, pgno, &pPage, pParent);
+  if( rc ) goto cleardatabasepage_out;
+  for(i=0; i<pPage->nCell; i++){
+    pCell = findCell(pPage, i);
+    if( !pPage->leaf ){
+      rc = clearDatabasePage(pBt, get4byte(pCell), pPage->pParent, 1);
+      if( rc ) goto cleardatabasepage_out;
+    }
+    rc = clearCell(pPage, pCell);
+    if( rc ) goto cleardatabasepage_out;
+  }
+  if( !pPage->leaf ){
+    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[8]), pPage->pParent, 1);
+    if( rc ) goto cleardatabasepage_out;
+  }
+  if( freePageFlag ){
+    rc = freePage(pPage);
+  }else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
+    zeroPage(pPage, pPage->aData[0] | PTF_LEAF);
+  }
+
+cleardatabasepage_out:
+  releasePage(pPage);
+  return rc;
+}
+
+/*
+** Delete all information from a single table in the database.  iTable is
+** the page number of the root of the table.  After this routine returns,
+** the root page is empty, but still exists.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** read cursors on the table.  Open write cursors are moved to the
+** root of the table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  if( p->inTrans!=TRANS_WRITE ){
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+  }else if( (rc = checkReadLocks(p, iTable, 0))!=SQLITE_OK ){
+    /* nothing to do */
+  }else if( SQLITE_OK!=(rc = saveAllCursors(pBt, iTable, 0)) ){
+    /* nothing to do */
+  }else{
+    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, 0);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Erase all information in a table and add the root of the table to
+** the freelist.  Except, the root of the principle table (the one on
+** page 1) is never added to the freelist.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** cursors on the table.
+**
+** If AUTOVACUUM is enabled and the page at iTable is not the last
+** root page in the database file, then the last root page 
+** in the database file is moved into the slot formerly occupied by
+** iTable and that last slot formerly occupied by the last root page
+** is added to the freelist instead of iTable.  In this say, all
+** root pages are kept at the beginning of the database file, which
+** is necessary for AUTOVACUUM to work right.  *piMoved is set to the 
+** page number that used to be the last root page in the file before
+** the move.  If no page gets moved, *piMoved is set to 0.
+** The last root page is recorded in meta[3] and the value of
+** meta[3] is updated by this procedure.
+*/
+static int btreeDropTable(Btree *p, int iTable, int *piMoved){
+  int rc;
+  MemPage *pPage = 0;
+  BtShared *pBt = p->pBt;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  if( p->inTrans!=TRANS_WRITE ){
+    return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+  }
+
+  /* It is illegal to drop a table if any cursors are open on the
+  ** database. This is because in auto-vacuum mode the backend may
+  ** need to move another root-page to fill a gap left by the deleted
+  ** root page. If an open cursor was using this page a problem would 
+  ** occur.
+  */
+  if( pBt->pCursor ){
+    return SQLITE_LOCKED;
+  }
+
+  rc = sqlite3BtreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
+  if( rc ) return rc;
+  rc = sqlite3BtreeClearTable(p, iTable);
+  if( rc ){
+    releasePage(pPage);
+    return rc;
+  }
+
+  *piMoved = 0;
+
+  if( iTable>1 ){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+    rc = freePage(pPage);
+    releasePage(pPage);
+#else
+    if( pBt->autoVacuum ){
+      Pgno maxRootPgno;
+      rc = sqlite3BtreeGetMeta(p, 4, &maxRootPgno);
+      if( rc!=SQLITE_OK ){
+        releasePage(pPage);
+        return rc;
+      }
+
+      if( iTable==maxRootPgno ){
+        /* If the table being dropped is the table with the largest root-page
+        ** number in the database, put the root page on the free list. 
+        */
+        rc = freePage(pPage);
+        releasePage(pPage);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+      }else{
+        /* The table being dropped does not have the largest root-page
+        ** number in the database. So move the page that does into the 
+        ** gap left by the deleted root-page.
+        */
+        MemPage *pMove;
+        releasePage(pPage);
+        rc = sqlite3BtreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable);
+        releasePage(pMove);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        rc = sqlite3BtreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        rc = freePage(pMove);
+        releasePage(pMove);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        *piMoved = maxRootPgno;
+      }
+
+      /* Set the new 'max-root-page' value in the database header. This
+      ** is the old value less one, less one more if that happens to
+      ** be a root-page number, less one again if that is the
+      ** PENDING_BYTE_PAGE.
+      */
+      maxRootPgno--;
+      if( maxRootPgno==PENDING_BYTE_PAGE(pBt) ){
+        maxRootPgno--;
+      }
+      if( maxRootPgno==PTRMAP_PAGENO(pBt, maxRootPgno) ){
+        maxRootPgno--;
+      }
+      assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
+
+      rc = sqlite3BtreeUpdateMeta(p, 4, maxRootPgno);
+    }else{
+      rc = freePage(pPage);
+      releasePage(pPage);
+    }
+#endif
+  }else{
+    /* If sqlite3BtreeDropTable was called on page 1. */
+    zeroPage(pPage, PTF_INTKEY|PTF_LEAF );
+    releasePage(pPage);
+  }
+  return rc;  
+}
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
+  int rc;
+  sqlite3BtreeEnter(p);
+  p->pBt->db = p->db;
+  rc = btreeDropTable(p, iTable, piMoved);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+/*
+** Read the meta-information out of a database file.  Meta[0]
+** is the number of free pages currently in the database.  Meta[1]
+** through meta[15] are available for use by higher layers.  Meta[0]
+** is read-only, the others are read/write.
+** 
+** The schema layer numbers meta values differently.  At the schema
+** layer (and the SetCookie and ReadCookie opcodes) the number of
+** free pages is not visible.  So Cookie[0] is the same as Meta[1].
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
+  DbPage *pDbPage;
+  int rc;
+  unsigned char *pP1;
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+
+  /* Reading a meta-data value requires a read-lock on page 1 (and hence
+  ** the sqlite_master table. We grab this lock regardless of whether or
+  ** not the SQLITE_ReadUncommitted flag is set (the table rooted at page
+  ** 1 is treated as a special case by queryTableLock() and lockTable()).
+  */
+  rc = queryTableLock(p, 1, READ_LOCK);
+  if( rc!=SQLITE_OK ){
+    sqlite3BtreeLeave(p);
+    return rc;
+  }
+
+  assert( idx>=0 && idx<=15 );
+  rc = sqlite3PagerGet(pBt->pPager, 1, &pDbPage);
+  if( rc ){
+    sqlite3BtreeLeave(p);
+    return rc;
+  }
+  pP1 = (unsigned char *)sqlite3PagerGetData(pDbPage);
+  *pMeta = get4byte(&pP1[36 + idx*4]);
+  sqlite3PagerUnref(pDbPage);
+
+  /* If autovacuumed is disabled in this build but we are trying to 
+  ** access an autovacuumed database, then make the database readonly. 
+  */
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  if( idx==4 && *pMeta>0 ) pBt->readOnly = 1;
+#endif
+
+  /* Grab the read-lock on page 1. */
+  rc = lockTable(p, 1, READ_LOCK);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Write meta-information back into the database.  Meta[0] is
+** read-only and may not be written.
+*/
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
+  BtShared *pBt = p->pBt;
+  unsigned char *pP1;
+  int rc;
+  assert( idx>=1 && idx<=15 );
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  if( p->inTrans!=TRANS_WRITE ){
+    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
+  }else{
+    assert( pBt->pPage1!=0 );
+    pP1 = pBt->pPage1->aData;
+    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+    if( rc==SQLITE_OK ){
+      put4byte(&pP1[36 + idx*4], iMeta);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( idx==7 ){
+        assert( pBt->autoVacuum || iMeta==0 );
+        assert( iMeta==0 || iMeta==1 );
+        pBt->incrVacuum = iMeta;
+      }
+#endif
+    }
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Return the flag byte at the beginning of the page that the cursor
+** is currently pointing to.
+*/
+SQLITE_PRIVATE int sqlite3BtreeFlags(BtCursor *pCur){
+  /* TODO: What about CURSOR_REQUIRESEEK state? Probably need to call
+  ** restoreOrClearCursorPosition() here.
+  */
+  MemPage *pPage;
+  restoreOrClearCursorPosition(pCur);
+  pPage = pCur->pPage;
+  assert( cursorHoldsMutex(pCur) );
+  assert( pPage->pBt==pCur->pBt );
+  return pPage ? pPage->aData[pPage->hdrOffset] : 0;
+}
+
+
+/*
+** Return the pager associated with a BTree.  This routine is used for
+** testing and debugging only.
+*/
+SQLITE_PRIVATE Pager *sqlite3BtreePager(Btree *p){
+  return p->pBt->pPager;
+}
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Append a message to the error message string.
+*/
+static void checkAppendMsg(
+  IntegrityCk *pCheck,
+  char *zMsg1,
+  const char *zFormat,
+  ...
+){
+  va_list ap;
+  char *zMsg2;
+  if( !pCheck->mxErr ) return;
+  pCheck->mxErr--;
+  pCheck->nErr++;
+  va_start(ap, zFormat);
+  zMsg2 = sqlite3VMPrintf(0, zFormat, ap);
+  va_end(ap);
+  if( zMsg1==0 ) zMsg1 = "";
+  if( pCheck->zErrMsg ){
+    char *zOld = pCheck->zErrMsg;
+    pCheck->zErrMsg = 0;
+    sqlite3SetString(&pCheck->zErrMsg, zOld, "\n", zMsg1, zMsg2, (char*)0);
+    sqlite3_free(zOld);
+  }else{
+    sqlite3SetString(&pCheck->zErrMsg, zMsg1, zMsg2, (char*)0);
+  }
+  sqlite3_free(zMsg2);
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Add 1 to the reference count for page iPage.  If this is the second
+** reference to the page, add an error message to pCheck->zErrMsg.
+** Return 1 if there are 2 ore more references to the page and 0 if
+** if this is the first reference to the page.
+**
+** Also check that the page number is in bounds.
+*/
+static int checkRef(IntegrityCk *pCheck, int iPage, char *zContext){
+  if( iPage==0 ) return 1;
+  if( iPage>pCheck->nPage || iPage<0 ){
+    checkAppendMsg(pCheck, zContext, "invalid page number %d", iPage);
+    return 1;
+  }
+  if( pCheck->anRef[iPage]==1 ){
+    checkAppendMsg(pCheck, zContext, "2nd reference to page %d", iPage);
+    return 1;
+  }
+  return  (pCheck->anRef[iPage]++)>1;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Check that the entry in the pointer-map for page iChild maps to 
+** page iParent, pointer type ptrType. If not, append an error message
+** to pCheck.
+*/
+static void checkPtrmap(
+  IntegrityCk *pCheck,   /* Integrity check context */
+  Pgno iChild,           /* Child page number */
+  u8 eType,              /* Expected pointer map type */
+  Pgno iParent,          /* Expected pointer map parent page number */
+  char *zContext         /* Context description (used for error msg) */
+){
+  int rc;
+  u8 ePtrmapType;
+  Pgno iPtrmapParent;
+
+  rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
+  if( rc!=SQLITE_OK ){
+    checkAppendMsg(pCheck, zContext, "Failed to read ptrmap key=%d", iChild);
+    return;
+  }
+
+  if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
+    checkAppendMsg(pCheck, zContext, 
+      "Bad ptr map entry key=%d expected=(%d,%d) got=(%d,%d)", 
+      iChild, eType, iParent, ePtrmapType, iPtrmapParent);
+  }
+}
+#endif
+
+/*
+** Check the integrity of the freelist or of an overflow page list.
+** Verify that the number of pages on the list is N.
+*/
+static void checkList(
+  IntegrityCk *pCheck,  /* Integrity checking context */
+  int isFreeList,       /* True for a freelist.  False for overflow page list */
+  int iPage,            /* Page number for first page in the list */
+  int N,                /* Expected number of pages in the list */
+  char *zContext        /* Context for error messages */
+){
+  int i;
+  int expected = N;
+  int iFirst = iPage;
+  while( N-- > 0 && pCheck->mxErr ){
+    DbPage *pOvflPage;
+    unsigned char *pOvflData;
+    if( iPage<1 ){
+      checkAppendMsg(pCheck, zContext,
+         "%d of %d pages missing from overflow list starting at %d",
+          N+1, expected, iFirst);
+      break;
+    }
+    if( checkRef(pCheck, iPage, zContext) ) break;
+    if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage) ){
+      checkAppendMsg(pCheck, zContext, "failed to get page %d", iPage);
+      break;
+    }
+    pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
+    if( isFreeList ){
+      int n = get4byte(&pOvflData[4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pCheck->pBt->autoVacuum ){
+        checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0, zContext);
+      }
+#endif
+      if( n>pCheck->pBt->usableSize/4-8 ){
+        checkAppendMsg(pCheck, zContext,
+           "freelist leaf count too big on page %d", iPage);
+        N--;
+      }else{
+        for(i=0; i<n; i++){
+          Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+          if( pCheck->pBt->autoVacuum ){
+            checkPtrmap(pCheck, iFreePage, PTRMAP_FREEPAGE, 0, zContext);
+          }
+#endif
+          checkRef(pCheck, iFreePage, zContext);
+        }
+        N -= n;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    else{
+      /* If this database supports auto-vacuum and iPage is not the last
+      ** page in this overflow list, check that the pointer-map entry for
+      ** the following page matches iPage.
+      */
+      if( pCheck->pBt->autoVacuum && N>0 ){
+        i = get4byte(pOvflData);
+        checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage, zContext);
+      }
+    }
+#endif
+    iPage = get4byte(pOvflData);
+    sqlite3PagerUnref(pOvflPage);
+  }
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Do various sanity checks on a single page of a tree.  Return
+** the tree depth.  Root pages return 0.  Parents of root pages
+** return 1, and so forth.
+** 
+** These checks are done:
+**
+**      1.  Make sure that cells and freeblocks do not overlap
+**          but combine to completely cover the page.
+**  NO  2.  Make sure cell keys are in order.
+**  NO  3.  Make sure no key is less than or equal to zLowerBound.
+**  NO  4.  Make sure no key is greater than or equal to zUpperBound.
+**      5.  Check the integrity of overflow pages.
+**      6.  Recursively call checkTreePage on all children.
+**      7.  Verify that the depth of all children is the same.
+**      8.  Make sure this page is at least 33% full or else it is
+**          the root of the tree.
+*/
+static int checkTreePage(
+  IntegrityCk *pCheck,  /* Context for the sanity check */
+  int iPage,            /* Page number of the page to check */
+  MemPage *pParent,     /* Parent page */
+  char *zParentContext  /* Parent context */
+){
+  MemPage *pPage;
+  int i, rc, depth, d2, pgno, cnt;
+  int hdr, cellStart;
+  int nCell;
+  u8 *data;
+  BtShared *pBt;
+  int usableSize;
+  char zContext[100];
+  char *hit;
+
+  sqlite3_snprintf(sizeof(zContext), zContext, "Page %d: ", iPage);
+
+  /* Check that the page exists
+  */
+  pBt = pCheck->pBt;
+  usableSize = pBt->usableSize;
+  if( iPage==0 ) return 0;
+  if( checkRef(pCheck, iPage, zParentContext) ) return 0;
+  if( (rc = sqlite3BtreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
+    checkAppendMsg(pCheck, zContext,
+       "unable to get the page. error code=%d", rc);
+    return 0;
+  }
+  if( (rc = sqlite3BtreeInitPage(pPage, pParent))!=0 ){
+    checkAppendMsg(pCheck, zContext, 
+                   "sqlite3BtreeInitPage() returns error code %d", rc);
+    releasePage(pPage);
+    return 0;
+  }
+
+  /* Check out all the cells.
+  */
+  depth = 0;
+  for(i=0; i<pPage->nCell && pCheck->mxErr; i++){
+    u8 *pCell;
+    int sz;
+    CellInfo info;
+
+    /* Check payload overflow pages
+    */
+    sqlite3_snprintf(sizeof(zContext), zContext,
+             "On tree page %d cell %d: ", iPage, i);
+    pCell = findCell(pPage,i);
+    sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+    sz = info.nData;
+    if( !pPage->intKey ) sz += info.nKey;
+    assert( sz==info.nPayload );
+    if( sz>info.nLocal ){
+      int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
+      Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage, zContext);
+      }
+#endif
+      checkList(pCheck, 0, pgnoOvfl, nPage, zContext);
+    }
+
+    /* Check sanity of left child page.
+    */
+    if( !pPage->leaf ){
+      pgno = get4byte(pCell);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
+      }
+#endif
+      d2 = checkTreePage(pCheck,pgno,pPage,zContext);
+      if( i>0 && d2!=depth ){
+        checkAppendMsg(pCheck, zContext, "Child page depth differs");
+      }
+      depth = d2;
+    }
+  }
+  if( !pPage->leaf ){
+    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    sqlite3_snprintf(sizeof(zContext), zContext, 
+                     "On page %d at right child: ", iPage);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, 0);
+    }
+#endif
+    checkTreePage(pCheck, pgno, pPage, zContext);
+  }
+ 
+  /* Check for complete coverage of the page
+  */
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  hit = sqlite3MallocZero( usableSize );
+  if( hit ){
+    memset(hit, 1, get2byte(&data[hdr+5]));
+    nCell = get2byte(&data[hdr+3]);
+    cellStart = hdr + 12 - 4*pPage->leaf;
+    for(i=0; i<nCell; i++){
+      int pc = get2byte(&data[cellStart+i*2]);
+      u16 size = cellSizePtr(pPage, &data[pc]);
+      int j;
+      if( (pc+size-1)>=usableSize || pc<0 ){
+        checkAppendMsg(pCheck, 0, 
+            "Corruption detected in cell %d on page %d",i,iPage,0);
+      }else{
+        for(j=pc+size-1; j>=pc; j--) hit[j]++;
+      }
+    }
+    for(cnt=0, i=get2byte(&data[hdr+1]); i>0 && i<usableSize && cnt<10000; 
+           cnt++){
+      int size = get2byte(&data[i+2]);
+      int j;
+      if( (i+size-1)>=usableSize || i<0 ){
+        checkAppendMsg(pCheck, 0,  
+            "Corruption detected in cell %d on page %d",i,iPage,0);
+      }else{
+        for(j=i+size-1; j>=i; j--) hit[j]++;
+      }
+      i = get2byte(&data[i]);
+    }
+    for(i=cnt=0; i<usableSize; i++){
+      if( hit[i]==0 ){
+        cnt++;
+      }else if( hit[i]>1 ){
+        checkAppendMsg(pCheck, 0,
+          "Multiple uses for byte %d of page %d", i, iPage);
+        break;
+      }
+    }
+    if( cnt!=data[hdr+7] ){
+      checkAppendMsg(pCheck, 0, 
+          "Fragmented space is %d byte reported as %d on page %d",
+          cnt, data[hdr+7], iPage);
+    }
+  }
+  sqlite3_free(hit);
+
+  releasePage(pPage);
+  return depth+1;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** This routine does a complete check of the given BTree file.  aRoot[] is
+** an array of pages numbers were each page number is the root page of
+** a table.  nRoot is the number of entries in aRoot.
+**
+** If everything checks out, this routine returns NULL.  If something is
+** amiss, an error message is written into memory obtained from malloc()
+** and a pointer to that error message is returned.  The calling function
+** is responsible for freeing the error message when it is done.
+*/
+SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
+  Btree *p,     /* The btree to be checked */
+  int *aRoot,   /* An array of root pages numbers for individual trees */
+  int nRoot,    /* Number of entries in aRoot[] */
+  int mxErr,    /* Stop reporting errors after this many */
+  int *pnErr    /* Write number of errors seen to this variable */
+){
+  int i;
+  int nRef;
+  IntegrityCk sCheck;
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  pBt->db = p->db;
+  nRef = sqlite3PagerRefcount(pBt->pPager);
+  if( lockBtreeWithRetry(p)!=SQLITE_OK ){
+    sqlite3BtreeLeave(p);
+    return sqlite3StrDup("Unable to acquire a read lock on the database");
+  }
+  sCheck.pBt = pBt;
+  sCheck.pPager = pBt->pPager;
+  sCheck.nPage = sqlite3PagerPagecount(sCheck.pPager);
+  sCheck.mxErr = mxErr;
+  sCheck.nErr = 0;
+  *pnErr = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( pBt->nTrunc!=0 ){
+    sCheck.nPage = pBt->nTrunc;
+  }
+#endif
+  if( sCheck.nPage==0 ){
+    unlockBtreeIfUnused(pBt);
+    sqlite3BtreeLeave(p);
+    return 0;
+  }
+  sCheck.anRef = sqlite3_malloc( (sCheck.nPage+1)*sizeof(sCheck.anRef[0]) );
+  if( !sCheck.anRef ){
+    unlockBtreeIfUnused(pBt);
+    *pnErr = 1;
+    sqlite3BtreeLeave(p);
+    return sqlite3MPrintf(p->db, "Unable to malloc %d bytes", 
+        (sCheck.nPage+1)*sizeof(sCheck.anRef[0]));
+  }
+  for(i=0; i<=sCheck.nPage; i++){ sCheck.anRef[i] = 0; }
+  i = PENDING_BYTE_PAGE(pBt);
+  if( i<=sCheck.nPage ){
+    sCheck.anRef[i] = 1;
+  }
+  sCheck.zErrMsg = 0;
+
+  /* Check the integrity of the freelist
+  */
+  checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
+            get4byte(&pBt->pPage1->aData[36]), "Main freelist: ");
+
+  /* Check all the tables.
+  */
+  for(i=0; i<nRoot && sCheck.mxErr; i++){
+    if( aRoot[i]==0 ) continue;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum && aRoot[i]>1 ){
+      checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0, 0);
+    }
+#endif
+    checkTreePage(&sCheck, aRoot[i], 0, "List of tree roots: ");
+  }
+
+  /* Make sure every page in the file is referenced
+  */
+  for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+    if( sCheck.anRef[i]==0 ){
+      checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
+    }
+#else
+    /* If the database supports auto-vacuum, make sure no tables contain
+    ** references to pointer-map pages.
+    */
+    if( sCheck.anRef[i]==0 && 
+       (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
+      checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
+    }
+    if( sCheck.anRef[i]!=0 && 
+       (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
+      checkAppendMsg(&sCheck, 0, "Pointer map page %d is referenced", i);
+    }
+#endif
+  }
+
+  /* Make sure this analysis did not leave any unref() pages
+  */
+  unlockBtreeIfUnused(pBt);
+  if( nRef != sqlite3PagerRefcount(pBt->pPager) ){
+    checkAppendMsg(&sCheck, 0, 
+      "Outstanding page count goes from %d to %d during this analysis",
+      nRef, sqlite3PagerRefcount(pBt->pPager)
+    );
+  }
+
+  /* Clean  up and report errors.
+  */
+  sqlite3BtreeLeave(p);
+  sqlite3_free(sCheck.anRef);
+  *pnErr = sCheck.nErr;
+  return sCheck.zErrMsg;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/*
+** Return the full pathname of the underlying database file.
+**
+** The pager filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerFilename(p->pBt->pPager);
+}
+
+/*
+** Return the pathname of the directory that contains the database file.
+**
+** The pager directory name is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetDirname(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerDirname(p->pBt->pPager);
+}
+
+/*
+** Return the pathname of the journal file for this database. The return
+** value of this routine is the same regardless of whether the journal file
+** has been created or not.
+**
+** The pager journal filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerJournalname(p->pBt->pPager);
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Copy the complete content of pBtFrom into pBtTo.  A transaction
+** must be active for both files.
+**
+** The size of file pTo may be reduced by this operation.
+** If anything goes wrong, the transaction on pTo is rolled back. 
+**
+** If successful, CommitPhaseOne() may be called on pTo before returning. 
+** The caller should finish committing the transaction on pTo by calling
+** sqlite3BtreeCommit().
+*/
+static int btreeCopyFile(Btree *pTo, Btree *pFrom){
+  int rc = SQLITE_OK;
+  Pgno i;
+
+  Pgno nFromPage;     /* Number of pages in pFrom */
+  Pgno nToPage;       /* Number of pages in pTo */
+  Pgno nNewPage;      /* Number of pages in pTo after the copy */
+
+  Pgno iSkip;         /* Pending byte page in pTo */
+  int nToPageSize;    /* Page size of pTo in bytes */
+  int nFromPageSize;  /* Page size of pFrom in bytes */
+
+  BtShared *pBtTo = pTo->pBt;
+  BtShared *pBtFrom = pFrom->pBt;
+  pBtTo->db = pTo->db;
+  pBtFrom->db = pFrom->db;
+
+  nToPageSize = pBtTo->pageSize;
+  nFromPageSize = pBtFrom->pageSize;
+
+  if( pTo->inTrans!=TRANS_WRITE || pFrom->inTrans!=TRANS_WRITE ){
+    return SQLITE_ERROR;
+  }
+  if( pBtTo->pCursor ){
+    return SQLITE_BUSY;
+  }
+
+  nToPage = sqlite3PagerPagecount(pBtTo->pPager);
+  nFromPage = sqlite3PagerPagecount(pBtFrom->pPager);
+  iSkip = PENDING_BYTE_PAGE(pBtTo);
+
+  /* Variable nNewPage is the number of pages required to store the
+  ** contents of pFrom using the current page-size of pTo.
+  */
+  nNewPage = ((i64)nFromPage * (i64)nFromPageSize + (i64)nToPageSize - 1) / 
+      (i64)nToPageSize;
+
+  for(i=1; rc==SQLITE_OK && (i<=nToPage || i<=nNewPage); i++){
+
+    /* Journal the original page.
+    **
+    ** iSkip is the page number of the locking page (PENDING_BYTE_PAGE)
+    ** in database *pTo (before the copy). This page is never written 
+    ** into the journal file. Unless i==iSkip or the page was not
+    ** present in pTo before the copy operation, journal page i from pTo.
+    */
+    if( i!=iSkip && i<=nToPage ){
+      DbPage *pDbPage = 0;
+      rc = sqlite3PagerGet(pBtTo->pPager, i, &pDbPage);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pDbPage);
+        if( rc==SQLITE_OK && i>nFromPage ){
+          /* Yeah.  It seems wierd to call DontWrite() right after Write(). But
+          ** that is because the names of those procedures do not exactly 
+          ** represent what they do.  Write() really means "put this page in the
+          ** rollback journal and mark it as dirty so that it will be written
+          ** to the database file later."  DontWrite() undoes the second part of
+          ** that and prevents the page from being written to the database. The
+          ** page is still on the rollback journal, though.  And that is the 
+          ** whole point of this block: to put pages on the rollback journal. 
+          */
+          sqlite3PagerDontWrite(pDbPage);
+        }
+        sqlite3PagerUnref(pDbPage);
+      }
+    }
+
+    /* Overwrite the data in page i of the target database */
+    if( rc==SQLITE_OK && i!=iSkip && i<=nNewPage ){
+
+      DbPage *pToPage = 0;
+      sqlite3_int64 iOff;
+
+      rc = sqlite3PagerGet(pBtTo->pPager, i, &pToPage);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pToPage);
+      }
+
+      for(
+        iOff=(i-1)*nToPageSize; 
+        rc==SQLITE_OK && iOff<i*nToPageSize; 
+        iOff += nFromPageSize
+      ){
+        DbPage *pFromPage = 0;
+        Pgno iFrom = (iOff/nFromPageSize)+1;
+
+        if( iFrom==PENDING_BYTE_PAGE(pBtFrom) ){
+          continue;
+        }
+
+        rc = sqlite3PagerGet(pBtFrom->pPager, iFrom, &pFromPage);
+        if( rc==SQLITE_OK ){
+          char *zTo = sqlite3PagerGetData(pToPage);
+          char *zFrom = sqlite3PagerGetData(pFromPage);
+          int nCopy;
+
+          if( nFromPageSize>=nToPageSize ){
+            zFrom += ((i-1)*nToPageSize - ((iFrom-1)*nFromPageSize));
+            nCopy = nToPageSize;
+          }else{
+            zTo += (((iFrom-1)*nFromPageSize) - (i-1)*nToPageSize);
+            nCopy = nFromPageSize;
+          }
+
+          memcpy(zTo, zFrom, nCopy);
+	  sqlite3PagerUnref(pFromPage);
+        }
+      }
+
+      if( pToPage ) sqlite3PagerUnref(pToPage);
+    }
+  }
+
+  /* If things have worked so far, the database file may need to be 
+  ** truncated. The complex part is that it may need to be truncated to
+  ** a size that is not an integer multiple of nToPageSize - the current
+  ** page size used by the pager associated with B-Tree pTo.
+  **
+  ** For example, say the page-size of pTo is 2048 bytes and the original 
+  ** number of pages is 5 (10 KB file). If pFrom has a page size of 1024 
+  ** bytes and 9 pages, then the file needs to be truncated to 9KB.
+  */
+  if( rc==SQLITE_OK ){
+    if( nFromPageSize!=nToPageSize ){
+      sqlite3_file *pFile = sqlite3PagerFile(pBtTo->pPager);
+      i64 iSize = (i64)nFromPageSize * (i64)nFromPage;
+      i64 iNow = (i64)((nToPage>nNewPage)?nToPage:nNewPage) * (i64)nToPageSize; 
+      i64 iPending = ((i64)PENDING_BYTE_PAGE(pBtTo)-1) *(i64)nToPageSize;
+  
+      assert( iSize<=iNow );
+  
+      /* Commit phase one syncs the journal file associated with pTo 
+      ** containing the original data. It does not sync the database file
+      ** itself. After doing this it is safe to use OsTruncate() and other
+      ** file APIs on the database file directly.
+      */
+      pBtTo->db = pTo->db;
+      rc = sqlite3PagerCommitPhaseOne(pBtTo->pPager, 0, 0, 1);
+      if( iSize<iNow && rc==SQLITE_OK ){
+        rc = sqlite3OsTruncate(pFile, iSize);
+      }
+  
+      /* The loop that copied data from database pFrom to pTo did not
+      ** populate the locking page of database pTo. If the page-size of
+      ** pFrom is smaller than that of pTo, this means some data will
+      ** not have been copied. 
+      **
+      ** This block copies the missing data from database pFrom to pTo 
+      ** using file APIs. This is safe because at this point we know that
+      ** all of the original data from pTo has been synced into the 
+      ** journal file. At this point it would be safe to do anything at
+      ** all to the database file except truncate it to zero bytes.
+      */
+      if( rc==SQLITE_OK && nFromPageSize<nToPageSize && iSize>iPending){
+        i64 iOff;
+        for(
+          iOff=iPending; 
+          rc==SQLITE_OK && iOff<(iPending+nToPageSize); 
+          iOff += nFromPageSize
+        ){
+          DbPage *pFromPage = 0;
+          Pgno iFrom = (iOff/nFromPageSize)+1;
+  
+          if( iFrom==PENDING_BYTE_PAGE(pBtFrom) || iFrom>nFromPage ){
+            continue;
+          }
+  
+          rc = sqlite3PagerGet(pBtFrom->pPager, iFrom, &pFromPage);
+          if( rc==SQLITE_OK ){
+            char *zFrom = sqlite3PagerGetData(pFromPage);
+  	  rc = sqlite3OsWrite(pFile, zFrom, nFromPageSize, iOff);
+            sqlite3PagerUnref(pFromPage);
+          }
+        }
+      }
+  
+      /* Sync the database file */
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerSync(pBtTo->pPager);
+      }
+    }else{
+      rc = sqlite3PagerTruncate(pBtTo->pPager, nNewPage);
+    }
+    if( rc==SQLITE_OK ){
+      pBtTo->pageSizeFixed = 0;
+    }
+  }
+
+  if( rc ){
+    sqlite3BtreeRollback(pTo);
+  }
+
+  return rc;  
+}
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
+  int rc;
+  sqlite3BtreeEnter(pTo);
+  sqlite3BtreeEnter(pFrom);
+  rc = btreeCopyFile(pTo, pFrom);
+  sqlite3BtreeLeave(pFrom);
+  sqlite3BtreeLeave(pTo);
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_VACUUM */
+
+/*
+** Return non-zero if a transaction is active.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsInTrans(Btree *p){
+  assert( p==0 || sqlite3_mutex_held(p->db->mutex) );
+  return (p && (p->inTrans==TRANS_WRITE));
+}
+
+/*
+** Return non-zero if a statement transaction is active.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsInStmt(Btree *p){
+  assert( sqlite3BtreeHoldsMutex(p) );
+  return (p->pBt && p->pBt->inStmt);
+}
+
+/*
+** Return non-zero if a read (or write) transaction is active.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree *p){
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  return (p && (p->inTrans!=TRANS_NONE));
+}
+
+/*
+** This function returns a pointer to a blob of memory associated with
+** a single shared-btree. The memory is used by client code for its own
+** purposes (for example, to store a high-level schema associated with 
+** the shared-btree). The btree layer manages reference counting issues.
+**
+** The first time this is called on a shared-btree, nBytes bytes of memory
+** are allocated, zeroed, and returned to the caller. For each subsequent 
+** call the nBytes parameter is ignored and a pointer to the same blob
+** of memory returned. 
+**
+** Just before the shared-btree is closed, the function passed as the 
+** xFree argument when the memory allocation was made is invoked on the 
+** blob of allocated memory. This function should not call sqlite3_free()
+** on the memory, the btree layer does that.
+*/
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  if( !pBt->pSchema ){
+    pBt->pSchema = sqlite3MallocZero(nBytes);
+    pBt->xFreeSchema = xFree;
+  }
+  sqlite3BtreeLeave(p);
+  return pBt->pSchema;
+}
+
+/*
+** Return true if another user of the same shared btree as the argument
+** handle holds an exclusive lock on the sqlite_master table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
+  int rc;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  rc = (queryTableLock(p, MASTER_ROOT, READ_LOCK)!=SQLITE_OK);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Obtain a lock on the table whose root page is iTab.  The
+** lock is a write lock if isWritelock is true or a read lock
+** if it is false.
+*/
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
+  int rc = SQLITE_OK;
+  if( p->sharable ){
+    u8 lockType = READ_LOCK + isWriteLock;
+    assert( READ_LOCK+1==WRITE_LOCK );
+    assert( isWriteLock==0 || isWriteLock==1 );
+    sqlite3BtreeEnter(p);
+    rc = queryTableLock(p, iTab, lockType);
+    if( rc==SQLITE_OK ){
+      rc = lockTable(p, iTab, lockType);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+#endif
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Argument pCsr must be a cursor opened for writing on an 
+** INTKEY table currently pointing at a valid table entry. 
+** This function modifies the data stored as part of that entry.
+** Only the data content may only be modified, it is not possible
+** to change the length of the data stored.
+*/
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
+  assert( cursorHoldsMutex(pCsr) );
+  assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
+  assert(pCsr->isIncrblobHandle);
+  if( pCsr->eState>=CURSOR_REQUIRESEEK ){
+    if( pCsr->eState==CURSOR_FAULT ){
+      return pCsr->skip;
+    }else{
+      return SQLITE_ABORT;
+    }
+  }
+
+  /* Check some preconditions: 
+  **   (a) the cursor is open for writing,
+  **   (b) there is no read-lock on the table being modified and
+  **   (c) the cursor points at a valid row of an intKey table.
+  */
+  if( !pCsr->wrFlag ){
+    return SQLITE_READONLY;
+  }
+  assert( !pCsr->pBt->readOnly 
+          && pCsr->pBt->inTransaction==TRANS_WRITE );
+  if( checkReadLocks(pCsr->pBtree, pCsr->pgnoRoot, pCsr) ){
+    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
+  }
+  if( pCsr->eState==CURSOR_INVALID || !pCsr->pPage->intKey ){
+    return SQLITE_ERROR;
+  }
+
+  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 0, 1);
+}
+
+/* 
+** Set a flag on this cursor to cache the locations of pages from the 
+** overflow list for the current row. This is used by cursors opened
+** for incremental blob IO only.
+**
+** This function sets a flag only. The actual page location cache
+** (stored in BtCursor.aOverflow[]) is allocated and used by function
+** accessPayload() (the worker function for sqlite3BtreeData() and
+** sqlite3BtreePutData()).
+*/
+SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert(!pCur->isIncrblobHandle);
+  assert(!pCur->aOverflow);
+  pCur->isIncrblobHandle = 1;
+}
+#endif
+
+/************** End of btree.c ***********************************************/
+/************** Begin file vdbefifo.c ****************************************/
+/*
+** 2005 June 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements a FIFO queue of rowids used for processing
+** UPDATE and DELETE statements.
+*/
+
+/*
+** Constants FIFOSIZE_FIRST and FIFOSIZE_MAX are the initial
+** number of entries in a fifo page and the maximum number of
+** entries in a fifo page.
+*/
+#define FIFOSIZE_FIRST (((128-sizeof(FifoPage))/8)+1)
+#ifdef SQLITE_MALLOC_SOFT_LIMIT
+# define FIFOSIZE_MAX   (((SQLITE_MALLOC_SOFT_LIMIT-sizeof(FifoPage))/8)+1)
+#else
+# define FIFOSIZE_MAX   (((262144-sizeof(FifoPage))/8)+1)
+#endif
+
+/*
+** Allocate a new FifoPage and return a pointer to it.  Return NULL if
+** we run out of memory.  Leave space on the page for nEntry entries.
+*/
+static FifoPage *allocateFifoPage(int nEntry){
+  FifoPage *pPage;
+  if( nEntry>FIFOSIZE_MAX ){
+    nEntry = FIFOSIZE_MAX;
+  }
+  pPage = sqlite3_malloc( sizeof(FifoPage) + sizeof(i64)*(nEntry-1) );
+  if( pPage ){
+    pPage->nSlot = nEntry;
+    pPage->iWrite = 0;
+    pPage->iRead = 0;
+    pPage->pNext = 0;
+  }
+  return pPage;
+}
+
+/*
+** Initialize a Fifo structure.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFifoInit(Fifo *pFifo){
+  memset(pFifo, 0, sizeof(*pFifo));
+}
+
+/*
+** Push a single 64-bit integer value into the Fifo.  Return SQLITE_OK
+** normally.   SQLITE_NOMEM is returned if we are unable to allocate
+** memory.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFifoPush(Fifo *pFifo, i64 val){
+  FifoPage *pPage;
+  pPage = pFifo->pLast;
+  if( pPage==0 ){
+    pPage = pFifo->pLast = pFifo->pFirst = allocateFifoPage(FIFOSIZE_FIRST);
+    if( pPage==0 ){
+      return SQLITE_NOMEM;
+    }
+  }else if( pPage->iWrite>=pPage->nSlot ){
+    pPage->pNext = allocateFifoPage(pFifo->nEntry);
+    if( pPage->pNext==0 ){
+      return SQLITE_NOMEM;
+    }
+    pPage = pFifo->pLast = pPage->pNext;
+  }
+  pPage->aSlot[pPage->iWrite++] = val;
+  pFifo->nEntry++;
+  return SQLITE_OK;
+}
+
+/*
+** Extract a single 64-bit integer value from the Fifo.  The integer
+** extracted is the one least recently inserted.  If the Fifo is empty
+** return SQLITE_DONE.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFifoPop(Fifo *pFifo, i64 *pVal){
+  FifoPage *pPage;
+  if( pFifo->nEntry==0 ){
+    return SQLITE_DONE;
+  }
+  assert( pFifo->nEntry>0 );
+  pPage = pFifo->pFirst;
+  assert( pPage!=0 );
+  assert( pPage->iWrite>pPage->iRead );
+  assert( pPage->iWrite<=pPage->nSlot );
+  assert( pPage->iRead<pPage->nSlot );
+  assert( pPage->iRead>=0 );
+  *pVal = pPage->aSlot[pPage->iRead++];
+  pFifo->nEntry--;
+  if( pPage->iRead>=pPage->iWrite ){
+    pFifo->pFirst = pPage->pNext;
+    sqlite3_free(pPage);
+    if( pFifo->nEntry==0 ){
+      assert( pFifo->pLast==pPage );
+      pFifo->pLast = 0;
+    }else{
+      assert( pFifo->pFirst!=0 );
+    }
+  }else{
+    assert( pFifo->nEntry>0 );
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Delete all information from a Fifo object.   Free all memory held
+** by the Fifo.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFifoClear(Fifo *pFifo){
+  FifoPage *pPage, *pNextPage;
+  for(pPage=pFifo->pFirst; pPage; pPage=pNextPage){
+    pNextPage = pPage->pNext;
+    sqlite3_free(pPage);
+  }
+  sqlite3VdbeFifoInit(pFifo);
+}
+
+/************** End of vdbefifo.c ********************************************/
+/************** Begin file vdbemem.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to manipulate "Mem" structure.  A "Mem"
+** stores a single value in the VDBE.  Mem is an opaque structure visible
+** only within the VDBE.  Interface routines refer to a Mem using the
+** name sqlite_value
+*/
+
+/*
+** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
+** P if required.
+*/
+#define expandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+
+/*
+** If pMem is an object with a valid string representation, this routine
+** ensures the internal encoding for the string representation is
+** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
+**
+** If pMem is not a string object, or the encoding of the string
+** representation is already stored using the requested encoding, then this
+** routine is a no-op.
+**
+** SQLITE_OK is returned if the conversion is successful (or not required).
+** SQLITE_NOMEM may be returned if a malloc() fails during conversion
+** between formats.
+*/
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
+  int rc;
+  if( !(pMem->flags&MEM_Str) || pMem->enc==desiredEnc ){
+    return SQLITE_OK;
+  }
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+#ifdef SQLITE_OMIT_UTF16
+  return SQLITE_ERROR;
+#else
+
+  /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
+  ** then the encoding of the value may not have changed.
+  */
+  rc = sqlite3VdbeMemTranslate(pMem, desiredEnc);
+  assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
+  assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
+  assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
+  return rc;
+#endif
+}
+
+/*
+** Make sure pMem->z points to a writable allocation of at least 
+** n bytes.
+**
+** If the memory cell currently contains string or blob data
+** and the third argument passed to this function is true, the 
+** current content of the cell is preserved. Otherwise, it may
+** be discarded.  
+**
+** This function sets the MEM_Dyn flag and clears any xDel callback.
+** It also clears MEM_Ephem and MEM_Static. If the preserve flag is 
+** not set, Mem.n is zeroed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
+  assert( 1 >=
+    ((pMem->zMalloc && pMem->zMalloc==pMem->z) ? 1 : 0) +
+    (((pMem->flags&MEM_Dyn)&&pMem->xDel) ? 1 : 0) + 
+    ((pMem->flags&MEM_Ephem) ? 1 : 0) + 
+    ((pMem->flags&MEM_Static) ? 1 : 0)
+  );
+
+  if( !pMem->zMalloc || sqlite3MallocSize(pMem->zMalloc)<n ){
+    n = (n>32?n:32);
+    if( preserve && pMem->z==pMem->zMalloc ){
+      pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
+      if( !pMem->z ){
+        pMem->flags = MEM_Null;
+      }
+      preserve = 0;
+    }else{
+      sqlite3_free(pMem->zMalloc);
+      pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
+    }
+  }
+
+  if( preserve && pMem->z && pMem->zMalloc && pMem->z!=pMem->zMalloc ){
+    memcpy(pMem->zMalloc, pMem->z, pMem->n);
+  }
+  if( pMem->flags&MEM_Dyn && pMem->xDel ){
+    pMem->xDel((void *)(pMem->z));
+  }
+
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= ~(MEM_Ephem|MEM_Static);
+  pMem->xDel = 0;
+  return (pMem->z ? SQLITE_OK : SQLITE_NOMEM);
+}
+
+/*
+** Make the given Mem object MEM_Dyn.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemDynamicify(Mem *pMem){
+  int f;
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  expandBlob(pMem);
+  f = pMem->flags;
+  if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
+    if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
+      return SQLITE_NOMEM;
+    }
+    pMem->z[pMem->n] = 0;
+    pMem->z[pMem->n+1] = 0;
+    pMem->flags |= MEM_Term;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** If the given Mem* has a zero-filled tail, turn it into an ordinary
+** blob stored in dynamically allocated space.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE int sqlite3VdbeMemExpandBlob(Mem *pMem){
+  if( pMem->flags & MEM_Zero ){
+    int nByte;
+    assert( pMem->flags&MEM_Blob );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+    /* Set nByte to the number of bytes required to store the expanded blob. */
+    nByte = pMem->n + pMem->u.i;
+    if( nByte<=0 ){
+      nByte = 1;
+    }
+    if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
+      return SQLITE_NOMEM;
+    }
+
+    memset(&pMem->z[pMem->n], 0, pMem->u.i);
+    pMem->n += pMem->u.i;
+    pMem->flags &= ~(MEM_Zero|MEM_Term);
+  }
+  return SQLITE_OK;
+}
+#endif
+
+
+/*
+** Make the given Mem object either MEM_Short or MEM_Dyn so that bytes
+** of the Mem.z[] array can be modified.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem *pMem){
+  return sqlite3VdbeMemDynamicify(pMem);
+}
+
+/*
+** Make sure the given Mem is \u0000 terminated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem *pMem){
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  if( (pMem->flags & MEM_Term)!=0 || (pMem->flags & MEM_Str)==0 ){
+    return SQLITE_OK;   /* Nothing to do */
+  }
+  if( sqlite3VdbeMemGrow(pMem, pMem->n+2, 1) ){
+    return SQLITE_NOMEM;
+  }
+  pMem->z[pMem->n] = 0;
+  pMem->z[pMem->n+1] = 0;
+  pMem->flags |= MEM_Term;
+  return SQLITE_OK;
+}
+
+/*
+** Add MEM_Str to the set of representations for the given Mem.  Numbers
+** are converted using sqlite3_snprintf().  Converting a BLOB to a string
+** is a no-op.
+**
+** Existing representations MEM_Int and MEM_Real are *not* invalidated.
+**
+** A MEM_Null value will never be passed to this function. This function is
+** used for converting values to text for returning to the user (i.e. via
+** sqlite3_value_text()), or for ensuring that values to be used as btree
+** keys are strings. In the former case a NULL pointer is returned the
+** user and the later is an internal programming error.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, int enc){
+  int rc = SQLITE_OK;
+  int fg = pMem->flags;
+  const int nByte = 32;
+
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !(fg&MEM_Zero) );
+  assert( !(fg&(MEM_Str|MEM_Blob)) );
+  assert( fg&(MEM_Int|MEM_Real) );
+
+  if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
+    return SQLITE_NOMEM;
+  }
+
+  /* For a Real or Integer, use sqlite3_mprintf() to produce the UTF-8
+  ** string representation of the value. Then, if the required encoding
+  ** is UTF-16le or UTF-16be do a translation.
+  ** 
+  ** FIX ME: It would be better if sqlite3_snprintf() could do UTF-16.
+  */
+  if( fg & MEM_Int ){
+    sqlite3_snprintf(nByte, pMem->z, "%lld", pMem->u.i);
+  }else{
+    assert( fg & MEM_Real );
+    sqlite3_snprintf(nByte, pMem->z, "%!.15g", pMem->r);
+  }
+  pMem->n = strlen(pMem->z);
+  pMem->enc = SQLITE_UTF8;
+  pMem->flags |= MEM_Str|MEM_Term;
+  sqlite3VdbeChangeEncoding(pMem, enc);
+  return rc;
+}
+
+/*
+** Memory cell pMem contains the context of an aggregate function.
+** This routine calls the finalize method for that function.  The
+** result of the aggregate is stored back into pMem.
+**
+** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
+** otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
+  int rc = SQLITE_OK;
+  if( pFunc && pFunc->xFinalize ){
+    sqlite3_context ctx;
+    assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+    ctx.s.flags = MEM_Null;
+    ctx.s.db = pMem->db;
+    ctx.s.zMalloc = 0;
+    ctx.pMem = pMem;
+    ctx.pFunc = pFunc;
+    ctx.isError = 0;
+    pFunc->xFinalize(&ctx);
+    assert( 0==(pMem->flags&MEM_Dyn) && !pMem->xDel );
+    sqlite3_free(pMem->zMalloc);
+    *pMem = ctx.s;
+    rc = (ctx.isError?SQLITE_ERROR:SQLITE_OK);
+  }
+  return rc;
+}
+
+/*
+** If the memory cell contains a string value that must be freed by
+** invoking an external callback, free it now. Calling this function
+** does not free any Mem.zMalloc buffer.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p){
+  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
+  if( p->flags&MEM_Agg ){
+    sqlite3VdbeMemFinalize(p, p->u.pDef);
+    assert( (p->flags & MEM_Agg)==0 );
+    sqlite3VdbeMemRelease(p);
+  }else if( p->flags&MEM_Dyn && p->xDel ){
+    p->xDel((void *)p->z);
+    p->xDel = 0;
+  }
+}
+
+/*
+** Release any memory held by the Mem. This may leave the Mem in an
+** inconsistent state, for example with (Mem.z==0) and
+** (Mem.type==SQLITE_TEXT).
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
+  sqlite3VdbeMemReleaseExternal(p);
+  sqlite3_free(p->zMalloc);
+  p->z = 0;
+  p->zMalloc = 0;
+  p->xDel = 0;
+}
+
+/*
+** Convert a 64-bit IEEE double into a 64-bit signed integer.
+** If the double is too large, return 0x8000000000000000.
+**
+** Most systems appear to do this simply by assigning
+** variables and without the extra range tests.  But
+** there are reports that windows throws an expection
+** if the floating point value is out of range. (See ticket #2880.)
+** Because we do not completely understand the problem, we will
+** take the conservative approach and always do range tests
+** before attempting the conversion.
+*/
+static i64 doubleToInt64(double r){
+  /*
+  ** Many compilers we encounter do not define constants for the
+  ** minimum and maximum 64-bit integers, or they define them
+  ** inconsistently.  And many do not understand the "LL" notation.
+  ** So we define our own static constants here using nothing
+  ** larger than a 32-bit integer constant.
+  */
+  static const i64 maxInt = LARGEST_INT64;
+  static const i64 minInt = SMALLEST_INT64;
+
+  if( r<(double)minInt ){
+    return minInt;
+  }else if( r>(double)maxInt ){
+    return minInt;
+  }else{
+    return (i64)r;
+  }
+}
+
+/*
+** Return some kind of integer value which is the best we can do
+** at representing the value that *pMem describes as an integer.
+** If pMem is an integer, then the value is exact.  If pMem is
+** a floating-point then the value returned is the integer part.
+** If pMem is a string or blob, then we make an attempt to convert
+** it into a integer and return that.  If pMem is NULL, return 0.
+**
+** If pMem is a string, its encoding might be changed.
+*/
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem *pMem){
+  int flags;
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  flags = pMem->flags;
+  if( flags & MEM_Int ){
+    return pMem->u.i;
+  }else if( flags & MEM_Real ){
+    return doubleToInt64(pMem->r);
+  }else if( flags & (MEM_Str|MEM_Blob) ){
+    i64 value;
+    pMem->flags |= MEM_Str;
+    if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
+       || sqlite3VdbeMemNulTerminate(pMem) ){
+      return 0;
+    }
+    assert( pMem->z );
+    sqlite3Atoi64(pMem->z, &value);
+    return value;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Return the best representation of pMem that we can get into a
+** double.  If pMem is already a double or an integer, return its
+** value.  If it is a string or blob, try to convert it to a double.
+** If it is a NULL, return 0.0.
+*/
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem *pMem){
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  if( pMem->flags & MEM_Real ){
+    return pMem->r;
+  }else if( pMem->flags & MEM_Int ){
+    return (double)pMem->u.i;
+  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
+    double val = 0.0;
+    pMem->flags |= MEM_Str;
+    if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
+       || sqlite3VdbeMemNulTerminate(pMem) ){
+      return 0.0;
+    }
+    assert( pMem->z );
+    sqlite3AtoF(pMem->z, &val);
+    return val;
+  }else{
+    return 0.0;
+  }
+}
+
+/*
+** The MEM structure is already a MEM_Real.  Try to also make it a
+** MEM_Int if we can.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem *pMem){
+  assert( pMem->flags & MEM_Real );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+  pMem->u.i = doubleToInt64(pMem->r);
+  if( pMem->r==(double)pMem->u.i ){
+    pMem->flags |= MEM_Int;
+  }
+}
+
+static void setTypeFlag(Mem *pMem, int f){
+  MemSetTypeFlag(pMem, f);
+}
+
+/*
+** Convert pMem to type integer.  Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem *pMem){
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  pMem->u.i = sqlite3VdbeIntValue(pMem);
+  setTypeFlag(pMem, MEM_Int);
+  return SQLITE_OK;
+}
+
+/*
+** Convert pMem so that it is of type MEM_Real.
+** Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem *pMem){
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  pMem->r = sqlite3VdbeRealValue(pMem);
+  setTypeFlag(pMem, MEM_Real);
+  return SQLITE_OK;
+}
+
+/*
+** Convert pMem so that it has types MEM_Real or MEM_Int or both.
+** Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
+  double r1, r2;
+  i64 i;
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))==0 );
+  assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  r1 = sqlite3VdbeRealValue(pMem);
+  i = doubleToInt64(r1);
+  r2 = (double)i;
+  if( r1==r2 ){
+    sqlite3VdbeMemIntegerify(pMem);
+  }else{
+    pMem->r = r1;
+    setTypeFlag(pMem, MEM_Real);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to NULL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem *pMem){
+  setTypeFlag(pMem, MEM_Null);
+  pMem->type = SQLITE_NULL;
+}
+
+/*
+** Delete any previous value and set the value to be a BLOB of length
+** n containing all zeros.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  sqlite3VdbeMemRelease(pMem);
+  setTypeFlag(pMem, MEM_Blob);
+  pMem->flags = MEM_Blob|MEM_Zero;
+  pMem->type = SQLITE_BLOB;
+  pMem->n = 0;
+  if( n<0 ) n = 0;
+  pMem->u.i = n;
+  pMem->enc = SQLITE_UTF8;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type INTEGER.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
+  sqlite3VdbeMemRelease(pMem);
+  pMem->u.i = val;
+  pMem->flags = MEM_Int;
+  pMem->type = SQLITE_INTEGER;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type REAL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
+  if( sqlite3IsNaN(val) ){
+    sqlite3VdbeMemSetNull(pMem);
+  }else{
+    sqlite3VdbeMemRelease(pMem);
+    pMem->r = val;
+    pMem->flags = MEM_Real;
+    pMem->type = SQLITE_FLOAT;
+  }
+}
+
+/*
+** Return true if the Mem object contains a TEXT or BLOB that is
+** too large - whose size exceeds SQLITE_MAX_LENGTH.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem *p){
+  assert( p->db!=0 );
+  if( p->flags & (MEM_Str|MEM_Blob) ){
+    int n = p->n;
+    if( p->flags & MEM_Zero ){
+      n += p->u.i;
+    }
+    return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  return 0; 
+}
+
+/*
+** Size of struct Mem not including the Mem.zMalloc member.
+*/
+#define MEMCELLSIZE (size_t)(&(((Mem *)0)->zMalloc))
+
+/*
+** Make an shallow copy of pFrom into pTo.  Prior contents of
+** pTo are freed.  The pFrom->z field is not duplicated.  If
+** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
+** and flags gets srcType (either MEM_Ephem or MEM_Static).
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
+  sqlite3VdbeMemReleaseExternal(pTo);
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  pTo->xDel = 0;
+  if( (pFrom->flags&MEM_Dyn)!=0 || pFrom->z==pFrom->zMalloc ){
+    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
+    assert( srcType==MEM_Ephem || srcType==MEM_Static );
+    pTo->flags |= srcType;
+  }
+}
+
+/*
+** Make a full copy of pFrom into pTo.  Prior contents of pTo are
+** freed before the copy is made.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
+  int rc = SQLITE_OK;
+
+  sqlite3VdbeMemReleaseExternal(pTo);
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  pTo->flags &= ~MEM_Dyn;
+
+  if( pTo->flags&(MEM_Str|MEM_Blob) ){
+    if( 0==(pFrom->flags&MEM_Static) ){
+      pTo->flags |= MEM_Ephem;
+      rc = sqlite3VdbeMemMakeWriteable(pTo);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Transfer the contents of pFrom to pTo. Any existing value in pTo is
+** freed. If pFrom contains ephemeral data, a copy is made.
+**
+** pFrom contains an SQL NULL when this routine returns.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
+  assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
+  assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
+  assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
+
+  sqlite3VdbeMemRelease(pTo);
+  memcpy(pTo, pFrom, sizeof(Mem));
+  pFrom->flags = MEM_Null;
+  pFrom->xDel = 0;
+  pFrom->zMalloc = 0;
+}
+
+/*
+** Change the value of a Mem to be a string or a BLOB.
+**
+** The memory management strategy depends on the value of the xDel
+** parameter. If the value passed is SQLITE_TRANSIENT, then the 
+** string is copied into a (possibly existing) buffer managed by the 
+** Mem structure. Otherwise, any existing buffer is freed and the
+** pointer copied.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
+  Mem *pMem,          /* Memory cell to set to string value */
+  const char *z,      /* String pointer */
+  int n,              /* Bytes in string, or negative */
+  u8 enc,             /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*) /* Destructor function */
+){
+  int nByte = n;      /* New value for pMem->n */
+  int flags = 0;      /* New value for pMem->flags */
+
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+  /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
+  if( !z ){
+    sqlite3VdbeMemSetNull(pMem);
+    return SQLITE_OK;
+  }
+
+  flags = (enc==0?MEM_Blob:MEM_Str);
+  if( nByte<0 ){
+    assert( enc!=0 );
+    if( enc==SQLITE_UTF8 ){
+      for(nByte=0; z[nByte]; nByte++){}
+    }else{
+      for(nByte=0; z[nByte] | z[nByte+1]; nByte+=2){}
+    }
+    flags |= MEM_Term;
+  }
+
+  /* The following block sets the new values of Mem.z and Mem.xDel. It
+  ** also sets a flag in local variable "flags" to indicate the memory
+  ** management (one of MEM_Dyn or MEM_Static).
+  */
+  if( xDel==SQLITE_TRANSIENT ){
+    int nAlloc = nByte;
+    if( flags&MEM_Term ){
+      nAlloc += (enc==SQLITE_UTF8?1:2);
+    }
+    if( sqlite3VdbeMemGrow(pMem, nAlloc, 0) ){
+      return SQLITE_NOMEM;
+    }
+    memcpy(pMem->z, z, nAlloc);
+  }else{
+    sqlite3VdbeMemRelease(pMem);
+    pMem->z = (char *)z;
+    pMem->xDel = xDel;
+    flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
+  }
+
+  pMem->n = nByte;
+  pMem->flags = flags;
+  pMem->enc = (enc==0 ? SQLITE_UTF8 : enc);
+  pMem->type = (enc==0 ? SQLITE_BLOB : SQLITE_TEXT);
+
+#ifndef SQLITE_OMIT_UTF16
+  if( pMem->enc!=SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
+    return SQLITE_NOMEM;
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** Compare the values contained by the two memory cells, returning
+** negative, zero or positive if pMem1 is less than, equal to, or greater
+** than pMem2. Sorting order is NULL's first, followed by numbers (integers
+** and reals) sorted numerically, followed by text ordered by the collating
+** sequence pColl and finally blob's ordered by memcmp().
+**
+** Two NULL values are considered equal by this function.
+*/
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const CollSeq *pColl){
+  int rc;
+  int f1, f2;
+  int combined_flags;
+
+  /* Interchange pMem1 and pMem2 if the collating sequence specifies
+  ** DESC order.
+  */
+  f1 = pMem1->flags;
+  f2 = pMem2->flags;
+  combined_flags = f1|f2;
+ 
+  /* If one value is NULL, it is less than the other. If both values
+  ** are NULL, return 0.
+  */
+  if( combined_flags&MEM_Null ){
+    return (f2&MEM_Null) - (f1&MEM_Null);
+  }
+
+  /* If one value is a number and the other is not, the number is less.
+  ** If both are numbers, compare as reals if one is a real, or as integers
+  ** if both values are integers.
+  */
+  if( combined_flags&(MEM_Int|MEM_Real) ){
+    if( !(f1&(MEM_Int|MEM_Real)) ){
+      return 1;
+    }
+    if( !(f2&(MEM_Int|MEM_Real)) ){
+      return -1;
+    }
+    if( (f1 & f2 & MEM_Int)==0 ){
+      double r1, r2;
+      if( (f1&MEM_Real)==0 ){
+        r1 = pMem1->u.i;
+      }else{
+        r1 = pMem1->r;
+      }
+      if( (f2&MEM_Real)==0 ){
+        r2 = pMem2->u.i;
+      }else{
+        r2 = pMem2->r;
+      }
+      if( r1<r2 ) return -1;
+      if( r1>r2 ) return 1;
+      return 0;
+    }else{
+      assert( f1&MEM_Int );
+      assert( f2&MEM_Int );
+      if( pMem1->u.i < pMem2->u.i ) return -1;
+      if( pMem1->u.i > pMem2->u.i ) return 1;
+      return 0;
+    }
+  }
+
+  /* If one value is a string and the other is a blob, the string is less.
+  ** If both are strings, compare using the collating functions.
+  */
+  if( combined_flags&MEM_Str ){
+    if( (f1 & MEM_Str)==0 ){
+      return 1;
+    }
+    if( (f2 & MEM_Str)==0 ){
+      return -1;
+    }
+
+    assert( pMem1->enc==pMem2->enc );
+    assert( pMem1->enc==SQLITE_UTF8 || 
+            pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );
+
+    /* The collation sequence must be defined at this point, even if
+    ** the user deletes the collation sequence after the vdbe program is
+    ** compiled (this was not always the case).
+    */
+    assert( !pColl || pColl->xCmp );
+
+    if( pColl ){
+      if( pMem1->enc==pColl->enc ){
+        /* The strings are already in the correct encoding.  Call the
+        ** comparison function directly */
+        return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
+      }else{
+        u8 origEnc = pMem1->enc;
+        const void *v1, *v2;
+        int n1, n2;
+        /* Convert the strings into the encoding that the comparison
+        ** function expects */
+        v1 = sqlite3ValueText((sqlite3_value*)pMem1, pColl->enc);
+        n1 = v1==0 ? 0 : pMem1->n;
+        assert( n1==sqlite3ValueBytes((sqlite3_value*)pMem1, pColl->enc) );
+        v2 = sqlite3ValueText((sqlite3_value*)pMem2, pColl->enc);
+        n2 = v2==0 ? 0 : pMem2->n;
+        assert( n2==sqlite3ValueBytes((sqlite3_value*)pMem2, pColl->enc) );
+        /* Do the comparison */
+        rc = pColl->xCmp(pColl->pUser, n1, v1, n2, v2);
+        /* Convert the strings back into the database encoding */
+        sqlite3ValueText((sqlite3_value*)pMem1, origEnc);
+        sqlite3ValueText((sqlite3_value*)pMem2, origEnc);
+        return rc;
+      }
+    }
+    /* If a NULL pointer was passed as the collate function, fall through
+    ** to the blob case and use memcmp().  */
+  }
+ 
+  /* Both values must be blobs.  Compare using memcmp().  */
+  rc = memcmp(pMem1->z, pMem2->z, (pMem1->n>pMem2->n)?pMem2->n:pMem1->n);
+  if( rc==0 ){
+    rc = pMem1->n - pMem2->n;
+  }
+  return rc;
+}
+
+/*
+** Move data out of a btree key or data field and into a Mem structure.
+** The data or key is taken from the entry that pCur is currently pointing
+** to.  offset and amt determine what portion of the data or key to retrieve.
+** key is true to get the key or false to get data.  The result is written
+** into the pMem element.
+**
+** The pMem structure is assumed to be uninitialized.  Any prior content
+** is overwritten without being freed.
+**
+** If this routine fails for any reason (malloc returns NULL or unable
+** to read from the disk) then the pMem is left in an inconsistent state.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  int offset,       /* Offset from the start of data to return bytes from. */
+  int amt,          /* Number of bytes to return. */
+  int key,          /* If true, retrieve from the btree key, not data. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  char *zData;       /* Data from the btree layer */
+  int available = 0; /* Number of bytes available on the local btree page */
+  sqlite3 *db;       /* Database connection */
+  int rc = SQLITE_OK;
+
+  db = sqlite3BtreeCursorDb(pCur);
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( key ){
+    zData = (char *)sqlite3BtreeKeyFetch(pCur, &available);
+  }else{
+    zData = (char *)sqlite3BtreeDataFetch(pCur, &available);
+  }
+  assert( zData!=0 );
+
+  if( offset+amt<=available && ((pMem->flags&MEM_Dyn)==0 || pMem->xDel) ){
+    sqlite3VdbeMemRelease(pMem);
+    pMem->z = &zData[offset];
+    pMem->flags = MEM_Blob|MEM_Ephem;
+  }else if( SQLITE_OK==(rc = sqlite3VdbeMemGrow(pMem, amt+2, 0)) ){
+    pMem->flags = MEM_Blob|MEM_Dyn|MEM_Term;
+    pMem->enc = 0;
+    pMem->type = SQLITE_BLOB;
+    if( key ){
+      rc = sqlite3BtreeKey(pCur, offset, amt, pMem->z);
+    }else{
+      rc = sqlite3BtreeData(pCur, offset, amt, pMem->z);
+    }
+    pMem->z[amt] = 0;
+    pMem->z[amt+1] = 0;
+    if( rc!=SQLITE_OK ){
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  pMem->n = amt;
+
+  return rc;
+}
+
+#if 0
+/*
+** Perform various checks on the memory cell pMem. An assert() will
+** fail if pMem is internally inconsistent.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSanity(Mem *pMem){
+  int flags = pMem->flags;
+  assert( flags!=0 );  /* Must define some type */
+  if( flags & (MEM_Str|MEM_Blob) ){
+    int x = flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
+    assert( x!=0 );            /* Strings must define a string subtype */
+    assert( (x & (x-1))==0 );  /* Only one string subtype can be defined */
+    assert( pMem->z!=0 );      /* Strings must have a value */
+    /* Mem.z points to Mem.zShort iff the subtype is MEM_Short */
+    assert( (x & MEM_Short)==0 || pMem->z==pMem->zShort );
+    assert( (x & MEM_Short)!=0 || pMem->z!=pMem->zShort );
+    /* No destructor unless there is MEM_Dyn */
+    assert( pMem->xDel==0 || (pMem->flags & MEM_Dyn)!=0 );
+
+    if( (flags & MEM_Str) ){
+      assert( pMem->enc==SQLITE_UTF8 || 
+              pMem->enc==SQLITE_UTF16BE ||
+              pMem->enc==SQLITE_UTF16LE 
+      );
+      /* If the string is UTF-8 encoded and nul terminated, then pMem->n
+      ** must be the length of the string.  (Later:)  If the database file
+      ** has been corrupted, '\000' characters might have been inserted
+      ** into the middle of the string.  In that case, the strlen() might
+      ** be less.
+      */
+      if( pMem->enc==SQLITE_UTF8 && (flags & MEM_Term) ){ 
+        assert( strlen(pMem->z)<=pMem->n );
+        assert( pMem->z[pMem->n]==0 );
+      }
+    }
+  }else{
+    /* Cannot define a string subtype for non-string objects */
+    assert( (pMem->flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short))==0 );
+    assert( pMem->xDel==0 );
+  }
+  /* MEM_Null excludes all other types */
+  assert( (pMem->flags&(MEM_Str|MEM_Int|MEM_Real|MEM_Blob))==0
+          || (pMem->flags&MEM_Null)==0 );
+  /* If the MEM is both real and integer, the values are equal */
+  assert( (pMem->flags & (MEM_Int|MEM_Real))!=(MEM_Int|MEM_Real) 
+          || pMem->r==pMem->u.i );
+}
+#endif
+
+/* This function is only available internally, it is not part of the
+** external API. It works in a similar way to sqlite3_value_text(),
+** except the data returned is in the encoding specified by the second
+** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
+** SQLITE_UTF8.
+**
+** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
+** If that is the case, then the result must be aligned on an even byte
+** boundary.
+*/
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
+  if( !pVal ) return 0;
+
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+
+  if( pVal->flags&MEM_Null ){
+    return 0;
+  }
+  assert( (MEM_Blob>>3) == MEM_Str );
+  pVal->flags |= (pVal->flags & MEM_Blob)>>3;
+  expandBlob(pVal);
+  if( pVal->flags&MEM_Str ){
+    sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
+    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&(int)pVal->z) ){
+      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
+      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
+        return 0;
+      }
+    }
+    sqlite3VdbeMemNulTerminate(pVal);
+  }else{
+    assert( (pVal->flags&MEM_Blob)==0 );
+    sqlite3VdbeMemStringify(pVal, enc);
+    assert( 0==(1&(int)pVal->z) );
+  }
+  assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
+              || pVal->db->mallocFailed );
+  if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
+    return pVal->z;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Create a new sqlite3_value object.
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *db){
+  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p ){
+    p->flags = MEM_Null;
+    p->type = SQLITE_NULL;
+    p->db = db;
+  }
+  return p;
+}
+
+/*
+** Create a new sqlite3_value object, containing the value of pExpr.
+**
+** This only works for very simple expressions that consist of one constant
+** token (i.e. "5", "5.1", "'a string'"). If the expression can
+** be converted directly into a value, then the value is allocated and
+** a pointer written to *ppVal. The caller is responsible for deallocating
+** the value by passing it to sqlite3ValueFree() later on. If the expression
+** cannot be converted to a value, then *ppVal is set to NULL.
+*/
+SQLITE_PRIVATE int sqlite3ValueFromExpr(
+  sqlite3 *db,              /* The database connection */
+  Expr *pExpr,              /* The expression to evaluate */
+  u8 enc,                   /* Encoding to use */
+  u8 affinity,              /* Affinity to use */
+  sqlite3_value **ppVal     /* Write the new value here */
+){
+  int op;
+  char *zVal = 0;
+  sqlite3_value *pVal = 0;
+
+  if( !pExpr ){
+    *ppVal = 0;
+    return SQLITE_OK;
+  }
+  op = pExpr->op;
+
+  if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
+    zVal = sqlite3StrNDup((char*)pExpr->token.z, pExpr->token.n);
+    pVal = sqlite3ValueNew(db);
+    if( !zVal || !pVal ) goto no_mem;
+    sqlite3Dequote(zVal);
+    sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, sqlite3_free);
+    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
+      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, enc);
+    }else{
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }else if( op==TK_UMINUS ) {
+    if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
+      pVal->u.i = -1 * pVal->u.i;
+      pVal->r = -1.0 * pVal->r;
+    }
+  }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+  else if( op==TK_BLOB ){
+    int nVal;
+    assert( pExpr->token.n>=3 );
+    assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
+    assert( pExpr->token.z[1]=='\'' );
+    assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
+    pVal = sqlite3ValueNew(db);
+    nVal = pExpr->token.n - 3;
+    zVal = (char*)pExpr->token.z + 2;
+    sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
+                         0, sqlite3_free);
+  }
+#endif
+
+  *ppVal = pVal;
+  return SQLITE_OK;
+
+no_mem:
+  db->mallocFailed = 1;
+  sqlite3_free(zVal);
+  sqlite3ValueFree(pVal);
+  *ppVal = 0;
+  return SQLITE_NOMEM;
+}
+
+/*
+** Change the string value of an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueSetStr(
+  sqlite3_value *v,     /* Value to be set */
+  int n,                /* Length of string z */
+  const void *z,        /* Text of the new string */
+  u8 enc,               /* Encoding to use */
+  void (*xDel)(void*)   /* Destructor for the string */
+){
+  if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
+}
+
+/*
+** Free an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value *v){
+  if( !v ) return;
+  sqlite3VdbeMemRelease((Mem *)v);
+  sqlite3_free(v);
+}
+
+/*
+** Return the number of bytes in the sqlite3_value object assuming
+** that it uses the encoding "enc"
+*/
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
+  Mem *p = (Mem*)pVal;
+  if( (p->flags & MEM_Blob)!=0 || sqlite3ValueText(pVal, enc) ){
+    if( p->flags & MEM_Zero ){
+      return p->n+p->u.i;
+    }else{
+      return p->n;
+    }
+  }
+  return 0;
+}
+
+/************** End of vdbemem.c *********************************************/
+/************** Begin file vdbeaux.c *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used for creating, destroying, and populating
+** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
+** to version 2.8.7, all this code was combined into the vdbe.c source file.
+** But that file was getting too big so this subroutines were split out.
+**
+** $Id: vdbeaux.c,v 1.383 2008/05/13 13:27:34 drh Exp $
+*/
+
+
+
+/*
+** When debugging the code generator in a symbolic debugger, one can
+** set the sqlite3VdbeAddopTrace to 1 and all opcodes will be printed
+** as they are added to the instruction stream.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3VdbeAddopTrace = 0;
+#endif
+
+
+/*
+** Create a new virtual database engine.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(sqlite3 *db){
+  Vdbe *p;
+  p = sqlite3DbMallocZero(db, sizeof(Vdbe) );
+  if( p==0 ) return 0;
+  p->db = db;
+  if( db->pVdbe ){
+    db->pVdbe->pPrev = p;
+  }
+  p->pNext = db->pVdbe;
+  p->pPrev = 0;
+  db->pVdbe = p;
+  p->magic = VDBE_MAGIC_INIT;
+  return p;
+}
+
+/*
+** Remember the SQL string for a prepared statement.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n){
+  if( p==0 ) return;
+  assert( p->zSql==0 );
+  p->zSql = sqlite3DbStrNDup(p->db, z, n);
+}
+
+/*
+** Return the SQL associated with a prepared statement
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
+  return ((Vdbe *)pStmt)->zSql;
+}
+
+/*
+** Swap all content between two VDBE structures.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
+  Vdbe tmp, *pTmp;
+  char *zTmp;
+  int nTmp;
+  tmp = *pA;
+  *pA = *pB;
+  *pB = tmp;
+  pTmp = pA->pNext;
+  pA->pNext = pB->pNext;
+  pB->pNext = pTmp;
+  pTmp = pA->pPrev;
+  pA->pPrev = pB->pPrev;
+  pB->pPrev = pTmp;
+  zTmp = pA->zSql;
+  pA->zSql = pB->zSql;
+  pB->zSql = zTmp;
+  nTmp = pA->nSql;
+  pA->nSql = pB->nSql;
+  pB->nSql = nTmp;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Turn tracing on or off
+*/
+SQLITE_PRIVATE void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
+  p->trace = trace;
+}
+#endif
+
+/*
+** Resize the Vdbe.aOp array so that it contains at least N
+** elements.
+**
+** If an out-of-memory error occurs while resizing the array,
+** Vdbe.aOp and Vdbe.nOpAlloc remain unchanged (this is so that
+** any opcodes already allocated can be correctly deallocated
+** along with the rest of the Vdbe).
+*/
+static void resizeOpArray(Vdbe *p, int N){
+  VdbeOp *pNew;
+  pNew = sqlite3DbRealloc(p->db, p->aOp, N*sizeof(Op));
+  if( pNew ){
+    p->nOpAlloc = N;
+    p->aOp = pNew;
+  }
+}
+
+/*
+** Add a new instruction to the list of instructions current in the
+** VDBE.  Return the address of the new instruction.
+**
+** Parameters:
+**
+**    p               Pointer to the VDBE
+**
+**    op              The opcode for this instruction
+**
+**    p1, p2, p3      Operands
+**
+** Use the sqlite3VdbeResolveLabel() function to fix an address and
+** the sqlite3VdbeChangeP4() function to change the value of the P4
+** operand.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p->nOpAlloc<=i ){
+    resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));
+    if( p->db->mallocFailed ){
+      return 0;
+    }
+  }
+  p->nOp++;
+  pOp = &p->aOp[i];
+  pOp->opcode = op;
+  pOp->p5 = 0;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = p3;
+  pOp->p4.p = 0;
+  pOp->p4type = P4_NOTUSED;
+  p->expired = 0;
+#ifdef SQLITE_DEBUG
+  pOp->zComment = 0;
+  if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+#endif
+#ifdef VDBE_PROFILE
+  pOp->cycles = 0;
+  pOp->cnt = 0;
+#endif
+  return i;
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe *p, int op){
+  return sqlite3VdbeAddOp3(p, op, 0, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){
+  return sqlite3VdbeAddOp3(p, op, p1, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){
+  return sqlite3VdbeAddOp3(p, op, p1, p2, 0);
+}
+
+
+/*
+** Add an opcode that includes the p4 value as a pointer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const char *zP4,    /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
+  return addr;
+}
+
+/*
+** Create a new symbolic label for an instruction that has yet to be
+** coded.  The symbolic label is really just a negative number.  The
+** label can be used as the P2 value of an operation.  Later, when
+** the label is resolved to a specific address, the VDBE will scan
+** through its operation list and change all values of P2 which match
+** the label into the resolved address.
+**
+** The VDBE knows that a P2 value is a label because labels are
+** always negative and P2 values are suppose to be non-negative.
+** Hence, a negative P2 value is a label that has yet to be resolved.
+**
+** Zero is returned if a malloc() fails.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Vdbe *p){
+  int i;
+  i = p->nLabel++;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( i>=p->nLabelAlloc ){
+    p->nLabelAlloc = p->nLabelAlloc*2 + 10;
+    p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,
+                                    p->nLabelAlloc*sizeof(p->aLabel[0]));
+  }
+  if( p->aLabel ){
+    p->aLabel[i] = -1;
+  }
+  return -1-i;
+}
+
+/*
+** Resolve label "x" to be the address of the next instruction to
+** be inserted.  The parameter "x" must have been obtained from
+** a prior call to sqlite3VdbeMakeLabel().
+*/
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe *p, int x){
+  int j = -1-x;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  assert( j>=0 && j<p->nLabel );
+  if( p->aLabel ){
+    p->aLabel[j] = p->nOp;
+  }
+}
+
+/*
+** Loop through the program looking for P2 values that are negative
+** on jump instructions.  Each such value is a label.  Resolve the
+** label by setting the P2 value to its correct non-zero value.
+**
+** This routine is called once after all opcodes have been inserted.
+**
+** Variable *pMaxFuncArgs is set to the maximum value of any P2 argument 
+** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by 
+** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
+**
+** This routine also does the following optimization:  It scans for
+** instructions that might cause a statement rollback.  Such instructions
+** are:
+**
+**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_Destroy
+**   *  OP_VUpdate
+**   *  OP_VRename
+**
+** If no such instruction is found, then every Statement instruction 
+** is changed to a Noop.  In this way, we avoid creating the statement 
+** journal file unnecessarily.
+*/
+static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
+  int i;
+  int nMaxArgs = 0;
+  Op *pOp;
+  int *aLabel = p->aLabel;
+  int doesStatementRollback = 0;
+  int hasStatementBegin = 0;
+  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+    u8 opcode = pOp->opcode;
+
+    if( opcode==OP_Function ){
+      if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
+    }else if( opcode==OP_AggStep 
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        || opcode==OP_VUpdate
+#endif
+    ){
+      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+    }
+    if( opcode==OP_Halt ){
+      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
+        doesStatementRollback = 1;
+      }
+    }else if( opcode==OP_Statement ){
+      hasStatementBegin = 1;
+    }else if( opcode==OP_Destroy ){
+      doesStatementRollback = 1;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    }else if( opcode==OP_VUpdate || opcode==OP_VRename ){
+      doesStatementRollback = 1;
+    }else if( opcode==OP_VFilter ){
+      int n;
+      assert( p->nOp - i >= 3 );
+      assert( pOp[-1].opcode==OP_Integer );
+      n = pOp[-1].p1;
+      if( n>nMaxArgs ) nMaxArgs = n;
+#endif
+    }
+
+    if( sqlite3VdbeOpcodeHasProperty(opcode, OPFLG_JUMP) && pOp->p2<0 ){
+      assert( -1-pOp->p2<p->nLabel );
+      pOp->p2 = aLabel[-1-pOp->p2];
+    }
+  }
+  sqlite3_free(p->aLabel);
+  p->aLabel = 0;
+
+  *pMaxFuncArgs = nMaxArgs;
+
+  /* If we never rollback a statement transaction, then statement
+  ** transactions are not needed.  So change every OP_Statement
+  ** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()
+  ** which can be expensive on some platforms.
+  */
+  if( hasStatementBegin && !doesStatementRollback ){
+    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+      if( pOp->opcode==OP_Statement ){
+        pOp->opcode = OP_Noop;
+      }
+    }
+  }
+}
+
+/*
+** Return the address of the next instruction to be inserted.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe *p){
+  assert( p->magic==VDBE_MAGIC_INIT );
+  return p->nOp;
+}
+
+/*
+** Add a whole list of operations to the operation stack.  Return the
+** address of the first operation added.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
+  int addr;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p->nOp + nOp > p->nOpAlloc ){
+    resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));
+    assert( p->nOp+nOp<=p->nOpAlloc || p->db->mallocFailed );
+  }
+  if( p->db->mallocFailed ){
+    return 0;
+  }
+  addr = p->nOp;
+  if( nOp>0 ){
+    int i;
+    VdbeOpList const *pIn = aOp;
+    for(i=0; i<nOp; i++, pIn++){
+      int p2 = pIn->p2;
+      VdbeOp *pOut = &p->aOp[i+addr];
+      pOut->opcode = pIn->opcode;
+      pOut->p1 = pIn->p1;
+      if( p2<0 && sqlite3VdbeOpcodeHasProperty(pOut->opcode, OPFLG_JUMP) ){
+        pOut->p2 = addr + ADDR(p2);
+      }else{
+        pOut->p2 = p2;
+      }
+      pOut->p3 = pIn->p3;
+      pOut->p4type = P4_NOTUSED;
+      pOut->p4.p = 0;
+      pOut->p5 = 0;
+#ifdef SQLITE_DEBUG
+      pOut->zComment = 0;
+      if( sqlite3VdbeAddopTrace ){
+        sqlite3VdbePrintOp(0, i+addr, &p->aOp[i+addr]);
+      }
+#endif
+    }
+    p->nOp += nOp;
+  }
+  return addr;
+}
+
+/*
+** Change the value of the P1 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
+  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+    p->aOp[addr].p1 = val;
+  }
+}
+
+/*
+** Change the value of the P2 operand for a specific instruction.
+** This routine is useful for setting a jump destination.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
+  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+    p->aOp[addr].p2 = val;
+  }
+}
+
+/*
+** Change the value of the P3 operand for a specific instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
+  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+    p->aOp[addr].p3 = val;
+  }
+}
+
+/*
+** Change the value of the P5 operand for the most recently
+** added operation.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe *p, u8 val){
+  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+  if( p && p->aOp ){
+    assert( p->nOp>0 );
+    p->aOp[p->nOp-1].p5 = val;
+  }
+}
+
+/*
+** Change the P2 operand of instruction addr so that it points to
+** the address of the next instruction to be coded.
+*/
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe *p, int addr){
+  sqlite3VdbeChangeP2(p, addr, p->nOp);
+}
+
+
+/*
+** If the input FuncDef structure is ephemeral, then free it.  If
+** the FuncDef is not ephermal, then do nothing.
+*/
+static void freeEphemeralFunction(FuncDef *pDef){
+  if( pDef && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
+    sqlite3_free(pDef);
+  }
+}
+
+/*
+** Delete a P4 value if necessary.
+*/
+static void freeP4(int p4type, void *p3){
+  if( p3 ){
+    switch( p4type ){
+      case P4_REAL:
+      case P4_INT64:
+      case P4_MPRINTF:
+      case P4_DYNAMIC:
+      case P4_KEYINFO:
+      case P4_KEYINFO_HANDOFF: {
+        sqlite3_free(p3);
+        break;
+      }
+      case P4_VDBEFUNC: {
+        VdbeFunc *pVdbeFunc = (VdbeFunc *)p3;
+        freeEphemeralFunction(pVdbeFunc->pFunc);
+        sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
+        sqlite3_free(pVdbeFunc);
+        break;
+      }
+      case P4_FUNCDEF: {
+        freeEphemeralFunction((FuncDef*)p3);
+        break;
+      }
+      case P4_MEM: {
+        sqlite3ValueFree((sqlite3_value*)p3);
+        break;
+      }
+    }
+  }
+}
+
+
+/*
+** Change N opcodes starting at addr to No-ops.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
+  if( p && p->aOp ){
+    VdbeOp *pOp = &p->aOp[addr];
+    while( N-- ){
+      freeP4(pOp->p4type, pOp->p4.p);
+      memset(pOp, 0, sizeof(pOp[0]));
+      pOp->opcode = OP_Noop;
+      pOp++;
+    }
+  }
+}
+
+/*
+** Change the value of the P4 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+**
+** If n>=0 then the P4 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqlite3_malloc().
+** A value of n==0 means copy bytes of zP4 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP4.
+**
+** If n==P4_KEYINFO it means that zP4 is a pointer to a KeyInfo structure.
+** A copy is made of the KeyInfo structure into memory obtained from
+** sqlite3_malloc, to be freed when the Vdbe is finalized.
+** n==P4_KEYINFO_HANDOFF indicates that zP4 points to a KeyInfo structure
+** stored in memory that the caller has obtained from sqlite3_malloc. The 
+** caller should not free the allocation, it will be freed when the Vdbe is
+** finalized.
+** 
+** Other values of n (P4_STATIC, P4_COLLSEQ etc.) indicate that zP4 points
+** to a string or structure that is guaranteed to exist for the lifetime of
+** the Vdbe. In these cases we can just copy the pointer.
+**
+** If addr<0 then change P4 on the most recently inserted instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){
+  Op *pOp;
+  assert( p!=0 );
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p->aOp==0 || p->db->mallocFailed ){
+    if (n != P4_KEYINFO) {
+      freeP4(n, (void*)*(char**)&zP4);
+    }
+    return;
+  }
+  assert( addr<p->nOp );
+  if( addr<0 ){
+    addr = p->nOp - 1;
+    if( addr<0 ) return;
+  }
+  pOp = &p->aOp[addr];
+  freeP4(pOp->p4type, pOp->p4.p);
+  pOp->p4.p = 0;
+  if( n==P4_INT32 ){
+    /* Note: this cast is safe, because the origin data point was an int
+    ** that was cast to a (const char *). */
+    pOp->p4.i = (int)zP4;
+    pOp->p4type = n;
+  }else if( zP4==0 ){
+    pOp->p4.p = 0;
+    pOp->p4type = P4_NOTUSED;
+  }else if( n==P4_KEYINFO ){
+    KeyInfo *pKeyInfo;
+    int nField, nByte;
+
+    nField = ((KeyInfo*)zP4)->nField;
+    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
+    pKeyInfo = sqlite3_malloc( nByte );
+    pOp->p4.pKeyInfo = pKeyInfo;
+    if( pKeyInfo ){
+      memcpy(pKeyInfo, zP4, nByte);
+      /* In the current implementation, P4_KEYINFO is only ever used on
+      ** KeyInfo structures that have no aSortOrder component.  Elements
+      ** with an aSortOrder always use P4_KEYINFO_HANDOFF.  So we do not
+      ** need to bother with duplicating the aSortOrder. */
+      assert( pKeyInfo->aSortOrder==0 );
+#if 0
+      aSortOrder = pKeyInfo->aSortOrder;
+      if( aSortOrder ){
+        pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
+        memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
+      }
+#endif
+      pOp->p4type = P4_KEYINFO;
+    }else{
+      p->db->mallocFailed = 1;
+      pOp->p4type = P4_NOTUSED;
+    }
+  }else if( n==P4_KEYINFO_HANDOFF ){
+    pOp->p4.p = (void*)zP4;
+    pOp->p4type = P4_KEYINFO;
+  }else if( n<0 ){
+    pOp->p4.p = (void*)zP4;
+    pOp->p4type = n;
+  }else{
+    if( n==0 ) n = strlen(zP4);
+    pOp->p4.z = sqlite3DbStrNDup(p->db, zP4, n);
+    pOp->p4type = P4_DYNAMIC;
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Change the comment on the the most recently coded instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  assert( p->nOp>0 || p->aOp==0 );
+  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
+  if( p->nOp ){
+    char **pz = &p->aOp[p->nOp-1].zComment;
+    va_start(ap, zFormat);
+    sqlite3_free(*pz);
+    *pz = sqlite3VMPrintf(p->db, zFormat, ap);
+    va_end(ap);
+  }
+}
+#endif
+
+/*
+** Return the opcode for a given address.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+  assert( p->magic==VDBE_MAGIC_INIT );
+  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
+  return ((addr>=0 && addr<p->nOp)?(&p->aOp[addr]):0);
+}
+
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Compute a string that describes the P4 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+static char *displayP4(Op *pOp, char *zTemp, int nTemp){
+  char *zP4 = zTemp;
+  assert( nTemp>=20 );
+  switch( pOp->p4type ){
+    case P4_KEYINFO: {
+      int i, j;
+      KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
+      sqlite3_snprintf(nTemp, zTemp, "keyinfo(%d", pKeyInfo->nField);
+      i = strlen(zTemp);
+      for(j=0; j<pKeyInfo->nField; j++){
+        CollSeq *pColl = pKeyInfo->aColl[j];
+        if( pColl ){
+          int n = strlen(pColl->zName);
+          if( i+n>nTemp-6 ){
+            memcpy(&zTemp[i],",...",4);
+            break;
+          }
+          zTemp[i++] = ',';
+          if( pKeyInfo->aSortOrder && pKeyInfo->aSortOrder[j] ){
+            zTemp[i++] = '-';
+          }
+          memcpy(&zTemp[i], pColl->zName,n+1);
+          i += n;
+        }else if( i+4<nTemp-6 ){
+          memcpy(&zTemp[i],",nil",4);
+          i += 4;
+        }
+      }
+      zTemp[i++] = ')';
+      zTemp[i] = 0;
+      assert( i<nTemp );
+      break;
+    }
+    case P4_COLLSEQ: {
+      CollSeq *pColl = pOp->p4.pColl;
+      sqlite3_snprintf(nTemp, zTemp, "collseq(%.20s)", pColl->zName);
+      break;
+    }
+    case P4_FUNCDEF: {
+      FuncDef *pDef = pOp->p4.pFunc;
+      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
+      break;
+    }
+    case P4_INT64: {
+      sqlite3_snprintf(nTemp, zTemp, "%lld", *pOp->p4.pI64);
+      break;
+    }
+    case P4_INT32: {
+      sqlite3_snprintf(nTemp, zTemp, "%d", pOp->p4.i);
+      break;
+    }
+    case P4_REAL: {
+      sqlite3_snprintf(nTemp, zTemp, "%.16g", *pOp->p4.pReal);
+      break;
+    }
+    case P4_MEM: {
+      Mem *pMem = pOp->p4.pMem;
+      assert( (pMem->flags & MEM_Null)==0 );
+      if( pMem->flags & MEM_Str ){
+        zP4 = pMem->z;
+      }else if( pMem->flags & MEM_Int ){
+        sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
+      }else if( pMem->flags & MEM_Real ){
+        sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    case P4_VTAB: {
+      sqlite3_vtab *pVtab = pOp->p4.pVtab;
+      sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
+      break;
+    }
+#endif
+    default: {
+      zP4 = pOp->p4.z;
+      if( zP4==0 ){
+        zP4 = zTemp;
+        zTemp[0] = 0;
+      }
+    }
+  }
+  assert( zP4!=0 );
+  return zP4;
+}
+#endif
+
+/*
+** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
+**
+*/
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe *p, int i){
+  int mask;
+  assert( i>=0 && i<p->db->nDb );
+  assert( i<sizeof(p->btreeMask)*8 );
+  mask = 1<<i;
+  if( (p->btreeMask & mask)==0 ){
+    p->btreeMask |= mask;
+    sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);
+  }
+}
+
+
+#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Print a single opcode.  This routine is used for debugging only.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
+  char *zP4;
+  char zPtr[50];
+  static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-4s %.2X %s\n";
+  if( pOut==0 ) pOut = stdout;
+  zP4 = displayP4(pOp, zPtr, sizeof(zPtr));
+  fprintf(pOut, zFormat1, pc, 
+      sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, pOp->p3, zP4, pOp->p5,
+#ifdef SQLITE_DEBUG
+      pOp->zComment ? pOp->zComment : ""
+#else
+      ""
+#endif
+  );
+  fflush(pOut);
+}
+#endif
+
+/*
+** Release an array of N Mem elements
+*/
+static void releaseMemArray(Mem *p, int N, int freebuffers){
+  if( p && N ){
+    sqlite3 *db = p->db;
+    int malloc_failed = db->mallocFailed;
+    while( N-->0 ){
+      assert( N<2 || p[0].db==p[1].db );
+      if( freebuffers ){
+        sqlite3VdbeMemRelease(p);
+      }else{
+        sqlite3VdbeMemReleaseExternal(p);
+      }
+      p->flags = MEM_Null;
+      p++;
+    }
+    db->mallocFailed = malloc_failed;
+  }
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+SQLITE_PRIVATE int sqlite3VdbeReleaseBuffers(Vdbe *p){
+  int ii;
+  int nFree = 0;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  for(ii=1; ii<=p->nMem; ii++){
+    Mem *pMem = &p->aMem[ii];
+    if( pMem->z && pMem->flags&MEM_Dyn ){
+      assert( !pMem->xDel );
+      nFree += sqlite3MallocSize(pMem->z);
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  return nFree;
+}
+#endif
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Give a listing of the program in the virtual machine.
+**
+** The interface is the same as sqlite3VdbeExec().  But instead of
+** running the code, it invokes the callback once for each instruction.
+** This feature is used to implement "EXPLAIN".
+**
+** When p->explain==1, each instruction is listed.  When
+** p->explain==2, only OP_Explain instructions are listed and these
+** are shown in a different format.  p->explain==2 is used to implement
+** EXPLAIN QUERY PLAN.
+*/
+SQLITE_PRIVATE int sqlite3VdbeList(
+  Vdbe *p                   /* The VDBE */
+){
+  sqlite3 *db = p->db;
+  int i;
+  int rc = SQLITE_OK;
+  Mem *pMem = p->pResultSet = &p->aMem[1];
+
+  assert( p->explain );
+  if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
+  assert( db->magic==SQLITE_MAGIC_BUSY );
+  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
+
+  /* Even though this opcode does not use dynamic strings for
+  ** the result, result columns may become dynamic if the user calls
+  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+  */
+  releaseMemArray(pMem, p->nMem, 1);
+
+  do{
+    i = p->pc++;
+  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
+  if( i>=p->nOp ){
+    p->rc = SQLITE_OK;
+    rc = SQLITE_DONE;
+  }else if( db->u1.isInterrupted ){
+    p->rc = SQLITE_INTERRUPT;
+    rc = SQLITE_ERROR;
+    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(p->rc), (char*)0);
+  }else{
+    char *z;
+    Op *pOp = &p->aOp[i];
+    if( p->explain==1 ){
+      pMem->flags = MEM_Int;
+      pMem->type = SQLITE_INTEGER;
+      pMem->u.i = i;                                /* Program counter */
+      pMem++;
+  
+      pMem->flags = MEM_Static|MEM_Str|MEM_Term;
+      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode);  /* Opcode */
+      assert( pMem->z!=0 );
+      pMem->n = strlen(pMem->z);
+      pMem->type = SQLITE_TEXT;
+      pMem->enc = SQLITE_UTF8;
+      pMem++;
+    }
+
+    pMem->flags = MEM_Int;
+    pMem->u.i = pOp->p1;                          /* P1 */
+    pMem->type = SQLITE_INTEGER;
+    pMem++;
+
+    pMem->flags = MEM_Int;
+    pMem->u.i = pOp->p2;                          /* P2 */
+    pMem->type = SQLITE_INTEGER;
+    pMem++;
+
+    if( p->explain==1 ){
+      pMem->flags = MEM_Int;
+      pMem->u.i = pOp->p3;                          /* P3 */
+      pMem->type = SQLITE_INTEGER;
+      pMem++;
+    }
+
+    if( sqlite3VdbeMemGrow(pMem, 32, 0) ){            /* P4 */
+      p->db->mallocFailed = 1;
+      return SQLITE_NOMEM;
+    }
+    pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
+    z = displayP4(pOp, pMem->z, 32);
+    if( z!=pMem->z ){
+      sqlite3VdbeMemSetStr(pMem, z, -1, SQLITE_UTF8, 0);
+    }else{
+      assert( pMem->z!=0 );
+      pMem->n = strlen(pMem->z);
+      pMem->enc = SQLITE_UTF8;
+    }
+    pMem->type = SQLITE_TEXT;
+    pMem++;
+
+    if( p->explain==1 ){
+      if( sqlite3VdbeMemGrow(pMem, 4, 0) ){
+        p->db->mallocFailed = 1;
+        return SQLITE_NOMEM;
+      }
+      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
+      pMem->n = 2;
+      sqlite3_snprintf(3, pMem->z, "%.2x", pOp->p5);   /* P5 */
+      pMem->type = SQLITE_TEXT;
+      pMem->enc = SQLITE_UTF8;
+      pMem++;
+  
+#ifdef SQLITE_DEBUG
+      if( pOp->zComment ){
+        pMem->flags = MEM_Str|MEM_Term;
+        pMem->z = pOp->zComment;
+        pMem->n = strlen(pMem->z);
+        pMem->enc = SQLITE_UTF8;
+      }else
+#endif
+      {
+        pMem->flags = MEM_Null;                       /* Comment */
+        pMem->type = SQLITE_NULL;
+      }
+    }
+
+    p->nResColumn = 8 - 5*(p->explain-1);
+    p->rc = SQLITE_OK;
+    rc = SQLITE_ROW;
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintSql(Vdbe *p){
+  int nOp = p->nOp;
+  VdbeOp *pOp;
+  if( nOp<1 ) return;
+  pOp = &p->aOp[0];
+  if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+    const char *z = pOp->p4.z;
+    while( isspace(*(u8*)z) ) z++;
+    printf("SQL: [%s]\n", z);
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** Print an IOTRACE message showing SQL content.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIOTraceSql(Vdbe *p){
+  int nOp = p->nOp;
+  VdbeOp *pOp;
+  if( sqlite3IoTrace==0 ) return;
+  if( nOp<1 ) return;
+  pOp = &p->aOp[0];
+  if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+    int i, j;
+    char z[1000];
+    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
+    for(i=0; isspace((unsigned char)z[i]); i++){}
+    for(j=0; z[i]; i++){
+      if( isspace((unsigned char)z[i]) ){
+        if( z[i-1]!=' ' ){
+          z[j++] = ' ';
+        }
+      }else{
+        z[j++] = z[i];
+      }
+    }
+    z[j] = 0;
+    sqlite3IoTrace("SQL %s\n", z);
+  }
+}
+#endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */
+
+
+/*
+** Prepare a virtual machine for execution.  This involves things such
+** as allocating stack space and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().  
+**
+** This is the only way to move a VDBE from VDBE_MAGIC_INIT to
+** VDBE_MAGIC_RUN.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(
+  Vdbe *p,                       /* The VDBE */
+  int nVar,                      /* Number of '?' see in the SQL statement */
+  int nMem,                      /* Number of memory cells to allocate */
+  int nCursor,                   /* Number of cursors to allocate */
+  int isExplain                  /* True if the EXPLAIN keywords is present */
+){
+  int n;
+  sqlite3 *db = p->db;
+
+  assert( p!=0 );
+  assert( p->magic==VDBE_MAGIC_INIT );
+
+  /* There should be at least one opcode.
+  */
+  assert( p->nOp>0 );
+
+  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. This
+   * is because the call to resizeOpArray() below may shrink the
+   * p->aOp[] array to save memory if called when in VDBE_MAGIC_RUN 
+   * state.
+   */
+  p->magic = VDBE_MAGIC_RUN;
+
+  /* For each cursor required, also allocate a memory cell. Memory
+  ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
+  ** the vdbe program. Instead they are used to allocate space for
+  ** Cursor/BtCursor structures. The blob of memory associated with 
+  ** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
+  ** stores the blob of memory associated with cursor 1, etc.
+  **
+  ** See also: allocateCursor().
+  */
+  nMem += nCursor;
+
+  /*
+  ** Allocation space for registers.
+  */
+  if( p->aMem==0 ){
+    int nArg;       /* Maximum number of args passed to a user function. */
+    resolveP2Values(p, &nArg);
+    /*resizeOpArray(p, p->nOp);*/
+    assert( nVar>=0 );
+    if( isExplain && nMem<10 ){
+      p->nMem = nMem = 10;
+    }
+    p->aMem = sqlite3DbMallocZero(db,
+        nMem*sizeof(Mem)               /* aMem */
+      + nVar*sizeof(Mem)               /* aVar */
+      + nArg*sizeof(Mem*)              /* apArg */
+      + nVar*sizeof(char*)             /* azVar */
+      + nCursor*sizeof(Cursor*) + 1    /* apCsr */
+    );
+    if( !db->mallocFailed ){
+      p->aMem--;             /* aMem[] goes from 1..nMem */
+      p->nMem = nMem;        /*       not from 0..nMem-1 */
+      p->aVar = &p->aMem[nMem+1];
+      p->nVar = nVar;
+      p->okVar = 0;
+      p->apArg = (Mem**)&p->aVar[nVar];
+      p->azVar = (char**)&p->apArg[nArg];
+      p->apCsr = (Cursor**)&p->azVar[nVar];
+      p->nCursor = nCursor;
+      for(n=0; n<nVar; n++){
+        p->aVar[n].flags = MEM_Null;
+        p->aVar[n].db = db;
+      }
+      for(n=1; n<=nMem; n++){
+        p->aMem[n].flags = MEM_Null;
+        p->aMem[n].db = db;
+      }
+    }
+  }
+#ifdef SQLITE_DEBUG
+  for(n=1; n<p->nMem; n++){
+    assert( p->aMem[n].db==db );
+  }
+#endif
+
+  p->pc = -1;
+  p->rc = SQLITE_OK;
+  p->uniqueCnt = 0;
+  p->returnDepth = 0;
+  p->errorAction = OE_Abort;
+  p->explain |= isExplain;
+  p->magic = VDBE_MAGIC_RUN;
+  p->nChange = 0;
+  p->cacheCtr = 1;
+  p->minWriteFileFormat = 255;
+  p->openedStatement = 0;
+#ifdef VDBE_PROFILE
+  {
+    int i;
+    for(i=0; i<p->nOp; i++){
+      p->aOp[i].cnt = 0;
+      p->aOp[i].cycles = 0;
+    }
+  }
+#endif
+}
+
+/*
+** Close a VDBE cursor and release all the resources that cursor 
+** happens to hold.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, Cursor *pCx){
+  if( pCx==0 ){
+    return;
+  }
+  if( pCx->pCursor ){
+    sqlite3BtreeCloseCursor(pCx->pCursor);
+  }
+  if( pCx->pBt ){
+    sqlite3BtreeClose(pCx->pBt);
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( pCx->pVtabCursor ){
+    sqlite3_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
+    const sqlite3_module *pModule = pCx->pModule;
+    p->inVtabMethod = 1;
+    (void)sqlite3SafetyOff(p->db);
+    pModule->xClose(pVtabCursor);
+    (void)sqlite3SafetyOn(p->db);
+    p->inVtabMethod = 0;
+  }
+#endif
+  if( !pCx->ephemPseudoTable ){
+    sqlite3_free(pCx->pData);
+  }
+  /* memset(pCx, 0, sizeof(Cursor)); */
+  /* sqlite3_free(pCx->aType); */
+  /* sqlite3_free(pCx); */
+}
+
+/*
+** Close all cursors except for VTab cursors that are currently
+** in use.
+*/
+static void closeAllCursorsExceptActiveVtabs(Vdbe *p){
+  int i;
+  if( p->apCsr==0 ) return;
+  for(i=0; i<p->nCursor; i++){
+    Cursor *pC = p->apCsr[i];
+    if( pC && (!p->inVtabMethod || !pC->pVtabCursor) ){
+      sqlite3VdbeFreeCursor(p, pC);
+      p->apCsr[i] = 0;
+    }
+  }
+}
+
+/*
+** Clean up the VM after execution.
+**
+** This routine will automatically close any cursors, lists, and/or
+** sorters that were left open.  It also deletes the values of
+** variables in the aVar[] array.
+*/
+static void Cleanup(Vdbe *p, int freebuffers){
+  int i;
+  closeAllCursorsExceptActiveVtabs(p);
+  for(i=1; i<=p->nMem; i++){
+    MemSetTypeFlag(&p->aMem[i], MEM_Null);
+  }
+  releaseMemArray(&p->aMem[1], p->nMem, freebuffers);
+  sqlite3VdbeFifoClear(&p->sFifo);
+  if( p->contextStack ){
+    for(i=0; i<p->contextStackTop; i++){
+      sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
+    }
+    sqlite3_free(p->contextStack);
+  }
+  p->contextStack = 0;
+  p->contextStackDepth = 0;
+  p->contextStackTop = 0;
+  sqlite3_free(p->zErrMsg);
+  p->zErrMsg = 0;
+  p->pResultSet = 0;
+}
+
+/*
+** Set the number of result columns that will be returned by this SQL
+** statement. This is now set at compile time, rather than during
+** execution of the vdbe program so that sqlite3_column_count() can
+** be called on an SQL statement before sqlite3_step().
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
+  Mem *pColName;
+  int n;
+
+  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N, 1);
+  sqlite3_free(p->aColName);
+  n = nResColumn*COLNAME_N;
+  p->nResColumn = nResColumn;
+  p->aColName = pColName = (Mem*)sqlite3DbMallocZero(p->db, sizeof(Mem)*n );
+  if( p->aColName==0 ) return;
+  while( n-- > 0 ){
+    pColName->flags = MEM_Null;
+    pColName->db = p->db;
+    pColName++;
+  }
+}
+
+/*
+** Set the name of the idx'th column to be returned by the SQL statement.
+** zName must be a pointer to a nul terminated string.
+**
+** This call must be made after a call to sqlite3VdbeSetNumCols().
+**
+** If N==P4_STATIC  it means that zName is a pointer to a constant static
+** string and we can just copy the pointer. If it is P4_DYNAMIC, then 
+** the string is freed using sqlite3_free() when the vdbe is finished with
+** it. Otherwise, N bytes of zName are copied.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSetColName(Vdbe *p, int idx, int var, const char *zName, int N){
+  int rc;
+  Mem *pColName;
+  assert( idx<p->nResColumn );
+  assert( var<COLNAME_N );
+  if( p->db->mallocFailed ) return SQLITE_NOMEM;
+  assert( p->aColName!=0 );
+  pColName = &(p->aColName[idx+var*p->nResColumn]);
+  if( N==P4_DYNAMIC || N==P4_STATIC ){
+    rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, SQLITE_STATIC);
+  }else{
+    rc = sqlite3VdbeMemSetStr(pColName, zName, N, SQLITE_UTF8,SQLITE_TRANSIENT);
+  }
+  if( rc==SQLITE_OK && N==P4_DYNAMIC ){
+    pColName->flags &= (~MEM_Static);
+    pColName->zMalloc = pColName->z;
+  }
+  return rc;
+}
+
+/*
+** A read or write transaction may or may not be active on database handle
+** db. If a transaction is active, commit it. If there is a
+** write-transaction spanning more than one database file, this routine
+** takes care of the master journal trickery.
+*/
+static int vdbeCommit(sqlite3 *db){
+  int i;
+  int nTrans = 0;  /* Number of databases with an active write-transaction */
+  int rc = SQLITE_OK;
+  int needXcommit = 0;
+
+  /* Before doing anything else, call the xSync() callback for any
+  ** virtual module tables written in this transaction. This has to
+  ** be done before determining whether a master journal file is 
+  ** required, as an xSync() callback may add an attached database
+  ** to the transaction.
+  */
+  rc = sqlite3VtabSync(db, rc);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* This loop determines (a) if the commit hook should be invoked and
+  ** (b) how many database files have open write transactions, not 
+  ** including the temp database. (b) is important because if more than 
+  ** one database file has an open write transaction, a master journal
+  ** file is required for an atomic commit.
+  */ 
+  for(i=0; i<db->nDb; i++){ 
+    Btree *pBt = db->aDb[i].pBt;
+    if( sqlite3BtreeIsInTrans(pBt) ){
+      needXcommit = 1;
+      if( i!=1 ) nTrans++;
+    }
+  }
+
+  /* If there are any write-transactions at all, invoke the commit hook */
+  if( needXcommit && db->xCommitCallback ){
+    (void)sqlite3SafetyOff(db);
+    rc = db->xCommitCallback(db->pCommitArg);
+    (void)sqlite3SafetyOn(db);
+    if( rc ){
+      return SQLITE_CONSTRAINT;
+    }
+  }
+
+  /* The simple case - no more than one database file (not counting the
+  ** TEMP database) has a transaction active.   There is no need for the
+  ** master-journal.
+  **
+  ** If the return value of sqlite3BtreeGetFilename() is a zero length
+  ** string, it means the main database is :memory:.  In that case we do
+  ** not support atomic multi-file commits, so use the simple case then
+  ** too.
+  */
+  if( 0==strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt)) || nTrans<=1 ){
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, 0);
+      }
+    }
+
+    /* Do the commit only if all databases successfully complete phase 1. 
+    ** If one of the BtreeCommitPhaseOne() calls fails, this indicates an
+    ** IO error while deleting or truncating a journal file. It is unlikely,
+    ** but could happen. In this case abandon processing and return the error.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseTwo(pBt);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3VtabCommit(db);
+    }
+  }
+
+  /* The complex case - There is a multi-file write-transaction active.
+  ** This requires a master journal file to ensure the transaction is
+  ** committed atomicly.
+  */
+#ifndef SQLITE_OMIT_DISKIO
+  else{
+    sqlite3_vfs *pVfs = db->pVfs;
+    int needSync = 0;
+    char *zMaster = 0;   /* File-name for the master journal */
+    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+    sqlite3_file *pMaster = 0;
+    i64 offset = 0;
+
+    /* Select a master journal file name */
+    do {
+      u32 random;
+      sqlite3_free(zMaster);
+      sqlite3_randomness(sizeof(random), &random);
+      zMaster = sqlite3MPrintf(db, "%s-mj%08X", zMainFile, random&0x7fffffff);
+      if( !zMaster ){
+        return SQLITE_NOMEM;
+      }
+      rc = sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS);
+    }while( rc==1 );
+    if( rc!=0 ){
+      rc = SQLITE_IOERR_NOMEM;
+    }else{
+      /* Open the master journal. */
+      rc = sqlite3OsOpenMalloc(pVfs, zMaster, &pMaster, 
+          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
+          SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_MASTER_JOURNAL, 0
+      );
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(zMaster);
+      return rc;
+    }
+ 
+    /* Write the name of each database file in the transaction into the new
+    ** master journal file. If an error occurs at this point close
+    ** and delete the master journal file. All the individual journal files
+    ** still have 'null' as the master journal pointer, so they will roll
+    ** back independently if a failure occurs.
+    */
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( i==1 ) continue;   /* Ignore the TEMP database */
+      if( sqlite3BtreeIsInTrans(pBt) ){
+        char const *zFile = sqlite3BtreeGetJournalname(pBt);
+        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
+        if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
+          needSync = 1;
+        }
+        rc = sqlite3OsWrite(pMaster, zFile, strlen(zFile)+1, offset);
+        offset += strlen(zFile)+1;
+        if( rc!=SQLITE_OK ){
+          sqlite3OsCloseFree(pMaster);
+          sqlite3OsDelete(pVfs, zMaster, 0);
+          sqlite3_free(zMaster);
+          return rc;
+        }
+      }
+    }
+
+    /* Sync the master journal file. If the IOCAP_SEQUENTIAL device
+    ** flag is set this is not required.
+    */
+    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
+    if( (needSync 
+     && (0==(sqlite3OsDeviceCharacteristics(pMaster)&SQLITE_IOCAP_SEQUENTIAL))
+     && (rc=sqlite3OsSync(pMaster, SQLITE_SYNC_NORMAL))!=SQLITE_OK) ){
+      sqlite3OsCloseFree(pMaster);
+      sqlite3OsDelete(pVfs, zMaster, 0);
+      sqlite3_free(zMaster);
+      return rc;
+    }
+
+    /* Sync all the db files involved in the transaction. The same call
+    ** sets the master journal pointer in each individual journal. If
+    ** an error occurs here, do not delete the master journal file.
+    **
+    ** If the error occurs during the first call to
+    ** sqlite3BtreeCommitPhaseOne(), then there is a chance that the
+    ** master journal file will be orphaned. But we cannot delete it,
+    ** in case the master journal file name was written into the journal
+    ** file before the failure occured.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, zMaster);
+      }
+    }
+    sqlite3OsCloseFree(pMaster);
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(zMaster);
+      return rc;
+    }
+
+    /* Delete the master journal file. This commits the transaction. After
+    ** doing this the directory is synced again before any individual
+    ** transaction files are deleted.
+    */
+    rc = sqlite3OsDelete(pVfs, zMaster, 1);
+    sqlite3_free(zMaster);
+    zMaster = 0;
+    if( rc ){
+      return rc;
+    }
+
+    /* All files and directories have already been synced, so the following
+    ** calls to sqlite3BtreeCommitPhaseTwo() are only closing files and
+    ** deleting or truncating journals. If something goes wrong while
+    ** this is happening we don't really care. The integrity of the
+    ** transaction is already guaranteed, but some stray 'cold' journals
+    ** may be lying around. Returning an error code won't help matters.
+    */
+    disable_simulated_io_errors();
+    sqlite3FaultBeginBenign(SQLITE_FAULTINJECTOR_MALLOC);
+    for(i=0; i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        sqlite3BtreeCommitPhaseTwo(pBt);
+      }
+    }
+    sqlite3FaultEndBenign(SQLITE_FAULTINJECTOR_MALLOC);
+    enable_simulated_io_errors();
+
+    sqlite3VtabCommit(db);
+  }
+#endif
+
+  return rc;
+}
+
+/* 
+** This routine checks that the sqlite3.activeVdbeCnt count variable
+** matches the number of vdbe's in the list sqlite3.pVdbe that are
+** currently active. An assertion fails if the two counts do not match.
+** This is an internal self-check only - it is not an essential processing
+** step.
+**
+** This is a no-op if NDEBUG is defined.
+*/
+#ifndef NDEBUG
+static void checkActiveVdbeCnt(sqlite3 *db){
+  Vdbe *p;
+  int cnt = 0;
+  p = db->pVdbe;
+  while( p ){
+    if( p->magic==VDBE_MAGIC_RUN && p->pc>=0 ){
+      cnt++;
+    }
+    p = p->pNext;
+  }
+  assert( cnt==db->activeVdbeCnt );
+}
+#else
+#define checkActiveVdbeCnt(x)
+#endif
+
+/*
+** For every Btree that in database connection db which 
+** has been modified, "trip" or invalidate each cursor in
+** that Btree might have been modified so that the cursor
+** can never be used again.  This happens when a rollback
+*** occurs.  We have to trip all the other cursors, even
+** cursor from other VMs in different database connections,
+** so that none of them try to use the data at which they
+** were pointing and which now may have been changed due
+** to the rollback.
+**
+** Remember that a rollback can delete tables complete and
+** reorder rootpages.  So it is not sufficient just to save
+** the state of the cursor.  We have to invalidate the cursor
+** so that it is never used again.
+*/
+static void invalidateCursorsOnModifiedBtrees(sqlite3 *db){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p && sqlite3BtreeIsInTrans(p) ){
+      sqlite3BtreeTripAllCursors(p, SQLITE_ABORT);
+    }
+  }
+}
+
+/*
+** This routine is called the when a VDBE tries to halt.  If the VDBE
+** has made changes and is in autocommit mode, then commit those
+** changes.  If a rollback is needed, then do the rollback.
+**
+** This routine is the only way to move the state of a VM from
+** SQLITE_MAGIC_RUN to SQLITE_MAGIC_HALT.  It is harmless to
+** call this on a VM that is in the SQLITE_MAGIC_HALT state.
+**
+** Return an error code.  If the commit could not complete because of
+** lock contention, return SQLITE_BUSY.  If SQLITE_BUSY is returned, it
+** means the close did not happen and needs to be repeated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
+  sqlite3 *db = p->db;
+  int i;
+  int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */
+  int isSpecialError;            /* Set to true if SQLITE_NOMEM or IOERR */
+
+  /* This function contains the logic that determines if a statement or
+  ** transaction will be committed or rolled back as a result of the
+  ** execution of this virtual machine. 
+  **
+  ** If any of the following errors occur:
+  **
+  **     SQLITE_NOMEM
+  **     SQLITE_IOERR
+  **     SQLITE_FULL
+  **     SQLITE_INTERRUPT
+  **
+  ** Then the internal cache might have been left in an inconsistent
+  ** state.  We need to rollback the statement transaction, if there is
+  ** one, or the complete transaction if there is no statement transaction.
+  */
+
+  if( p->db->mallocFailed ){
+    p->rc = SQLITE_NOMEM;
+  }
+  closeAllCursorsExceptActiveVtabs(p);
+  if( p->magic!=VDBE_MAGIC_RUN ){
+    return SQLITE_OK;
+  }
+  checkActiveVdbeCnt(db);
+
+  /* No commit or rollback needed if the program never started */
+  if( p->pc>=0 ){
+    int mrc;   /* Primary error code from p->rc */
+
+    /* Lock all btrees used by the statement */
+    sqlite3BtreeMutexArrayEnter(&p->aMutex);
+
+    /* Check for one of the special errors */
+    mrc = p->rc & 0xff;
+    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
+                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
+    if( isSpecialError ){
+      /* This loop does static analysis of the query to see which of the
+      ** following three categories it falls into:
+      **
+      **     Read-only
+      **     Query with statement journal
+      **     Query without statement journal
+      **
+      ** We could do something more elegant than this static analysis (i.e.
+      ** store the type of query as part of the compliation phase), but 
+      ** handling malloc() or IO failure is a fairly obscure edge case so 
+      ** this is probably easier. Todo: Might be an opportunity to reduce 
+      ** code size a very small amount though...
+      */
+      int notReadOnly = 0;
+      int isStatement = 0;
+      assert(p->aOp || p->nOp==0);
+      for(i=0; i<p->nOp; i++){ 
+        switch( p->aOp[i].opcode ){
+          case OP_Transaction:
+            notReadOnly |= p->aOp[i].p2;
+            break;
+          case OP_Statement:
+            isStatement = 1;
+            break;
+        }
+      }
+
+   
+      /* If the query was read-only, we need do no rollback at all. Otherwise,
+      ** proceed with the special handling.
+      */
+      if( notReadOnly || mrc!=SQLITE_INTERRUPT ){
+        if( p->rc==SQLITE_IOERR_BLOCKED && isStatement ){
+          xFunc = sqlite3BtreeRollbackStmt;
+          p->rc = SQLITE_BUSY;
+        } else if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && isStatement ){
+          xFunc = sqlite3BtreeRollbackStmt;
+        }else{
+          /* We are forced to roll back the active transaction. Before doing
+          ** so, abort any other statements this handle currently has active.
+          */
+          invalidateCursorsOnModifiedBtrees(db);
+          sqlite3RollbackAll(db);
+          db->autoCommit = 1;
+        }
+      }
+    }
+  
+    /* If the auto-commit flag is set and this is the only active vdbe, then
+    ** we do either a commit or rollback of the current transaction. 
+    **
+    ** Note: This block also runs if one of the special errors handled 
+    ** above has occured. 
+    */
+    if( db->autoCommit && db->activeVdbeCnt==1 ){
+      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+        /* The auto-commit flag is true, and the vdbe program was 
+        ** successful or hit an 'OR FAIL' constraint. This means a commit 
+        ** is required.
+        */
+        int rc = vdbeCommit(db);
+        if( rc==SQLITE_BUSY ){
+          sqlite3BtreeMutexArrayLeave(&p->aMutex);
+          return SQLITE_BUSY;
+        }else if( rc!=SQLITE_OK ){
+          p->rc = rc;
+          sqlite3RollbackAll(db);
+        }else{
+          sqlite3CommitInternalChanges(db);
+        }
+      }else{
+        sqlite3RollbackAll(db);
+      }
+    }else if( !xFunc ){
+      if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+        if( p->openedStatement ){
+          xFunc = sqlite3BtreeCommitStmt;
+        } 
+      }else if( p->errorAction==OE_Abort ){
+        xFunc = sqlite3BtreeRollbackStmt;
+      }else{
+        invalidateCursorsOnModifiedBtrees(db);
+        sqlite3RollbackAll(db);
+        db->autoCommit = 1;
+      }
+    }
+  
+    /* If xFunc is not NULL, then it is one of sqlite3BtreeRollbackStmt or
+    ** sqlite3BtreeCommitStmt. Call it once on each backend. If an error occurs
+    ** and the return code is still SQLITE_OK, set the return code to the new
+    ** error value.
+    */
+    assert(!xFunc ||
+      xFunc==sqlite3BtreeCommitStmt ||
+      xFunc==sqlite3BtreeRollbackStmt
+    );
+    for(i=0; xFunc && i<db->nDb; i++){ 
+      int rc;
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = xFunc(pBt);
+        if( rc && (p->rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT) ){
+          p->rc = rc;
+          sqlite3SetString(&p->zErrMsg, 0);
+        }
+      }
+    }
+  
+    /* If this was an INSERT, UPDATE or DELETE and the statement was committed, 
+    ** set the change counter. 
+    */
+    if( p->changeCntOn && p->pc>=0 ){
+      if( !xFunc || xFunc==sqlite3BtreeCommitStmt ){
+        sqlite3VdbeSetChanges(db, p->nChange);
+      }else{
+        sqlite3VdbeSetChanges(db, 0);
+      }
+      p->nChange = 0;
+    }
+  
+    /* Rollback or commit any schema changes that occurred. */
+    if( p->rc!=SQLITE_OK && db->flags&SQLITE_InternChanges ){
+      sqlite3ResetInternalSchema(db, 0);
+      db->flags = (db->flags | SQLITE_InternChanges);
+    }
+
+    /* Release the locks */
+    sqlite3BtreeMutexArrayLeave(&p->aMutex);
+  }
+
+  /* We have successfully halted and closed the VM.  Record this fact. */
+  if( p->pc>=0 ){
+    db->activeVdbeCnt--;
+  }
+  p->magic = VDBE_MAGIC_HALT;
+  checkActiveVdbeCnt(db);
+  if( p->db->mallocFailed ){
+    p->rc = SQLITE_NOMEM;
+  }
+
+  return SQLITE_OK;
+}
+
+
+/*
+** Each VDBE holds the result of the most recent sqlite3_step() call
+** in p->rc.  This routine sets that result back to SQLITE_OK.
+*/
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe *p){
+  p->rc = SQLITE_OK;
+}
+
+/*
+** Clean up a VDBE after execution but do not delete the VDBE just yet.
+** Write any error messages into *pzErrMsg.  Return the result code.
+**
+** After this routine is run, the VDBE should be ready to be executed
+** again.
+**
+** To look at it another way, this routine resets the state of the
+** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
+** VDBE_MAGIC_INIT.
+*/
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe *p, int freebuffers){
+  sqlite3 *db;
+  db = p->db;
+
+  /* If the VM did not run to completion or if it encountered an
+  ** error, then it might not have been halted properly.  So halt
+  ** it now.
+  */
+  (void)sqlite3SafetyOn(db);
+  sqlite3VdbeHalt(p);
+  (void)sqlite3SafetyOff(db);
+
+  /* If the VDBE has be run even partially, then transfer the error code
+  ** and error message from the VDBE into the main database structure.  But
+  ** if the VDBE has just been set to run but has not actually executed any
+  ** instructions yet, leave the main database error information unchanged.
+  */
+  if( p->pc>=0 ){
+    if( p->zErrMsg ){
+      sqlite3ValueSetStr(db->pErr,-1,p->zErrMsg,SQLITE_UTF8,sqlite3_free);
+      db->errCode = p->rc;
+      p->zErrMsg = 0;
+    }else if( p->rc ){
+      sqlite3Error(db, p->rc, 0);
+    }else{
+      sqlite3Error(db, SQLITE_OK, 0);
+    }
+  }else if( p->rc && p->expired ){
+    /* The expired flag was set on the VDBE before the first call
+    ** to sqlite3_step(). For consistency (since sqlite3_step() was
+    ** called), set the database error in this case as well.
+    */
+    sqlite3Error(db, p->rc, 0);
+    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, sqlite3_free);
+    p->zErrMsg = 0;
+  }
+
+  /* Reclaim all memory used by the VDBE
+  */
+  Cleanup(p, freebuffers);
+
+  /* Save profiling information from this VDBE run.
+  */
+#ifdef VDBE_PROFILE
+  {
+    FILE *out = fopen("vdbe_profile.out", "a");
+    if( out ){
+      int i;
+      fprintf(out, "---- ");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%02x", p->aOp[i].opcode);
+      }
+      fprintf(out, "\n");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%6d %10lld %8lld ",
+           p->aOp[i].cnt,
+           p->aOp[i].cycles,
+           p->aOp[i].cnt>0 ? p->aOp[i].cycles/p->aOp[i].cnt : 0
+        );
+        sqlite3VdbePrintOp(out, i, &p->aOp[i]);
+      }
+      fclose(out);
+    }
+  }
+#endif
+  p->magic = VDBE_MAGIC_INIT;
+  p->aborted = 0;
+  return p->rc & db->errMask;
+}
+ 
+/*
+** Clean up and delete a VDBE after execution.  Return an integer which is
+** the result code.  Write any error message text into *pzErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe *p){
+  int rc = SQLITE_OK;
+  if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
+    rc = sqlite3VdbeReset(p, 1);
+    assert( (rc & p->db->errMask)==rc );
+  }else if( p->magic!=VDBE_MAGIC_INIT ){
+    return SQLITE_MISUSE;
+  }
+  releaseMemArray(&p->aMem[1], p->nMem, 1);
+  sqlite3VdbeDelete(p);
+  return rc;
+}
+
+/*
+** Call the destructor for each auxdata entry in pVdbeFunc for which
+** the corresponding bit in mask is clear.  Auxdata entries beyond 31
+** are always destroyed.  To destroy all auxdata entries, call this
+** routine with mask==0.
+*/
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc *pVdbeFunc, int mask){
+  int i;
+  for(i=0; i<pVdbeFunc->nAux; i++){
+    struct AuxData *pAux = &pVdbeFunc->apAux[i];
+    if( (i>31 || !(mask&(1<<i))) && pAux->pAux ){
+      if( pAux->xDelete ){
+        pAux->xDelete(pAux->pAux);
+      }
+      pAux->pAux = 0;
+    }
+  }
+}
+
+/*
+** Delete an entire VDBE.
+*/
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
+  int i;
+  if( p==0 ) return;
+  Cleanup(p, 1);
+  if( p->pPrev ){
+    p->pPrev->pNext = p->pNext;
+  }else{
+    assert( p->db->pVdbe==p );
+    p->db->pVdbe = p->pNext;
+  }
+  if( p->pNext ){
+    p->pNext->pPrev = p->pPrev;
+  }
+  if( p->aOp ){
+    Op *pOp = p->aOp;
+    for(i=0; i<p->nOp; i++, pOp++){
+      freeP4(pOp->p4type, pOp->p4.p);
+#ifdef SQLITE_DEBUG
+      sqlite3_free(pOp->zComment);
+#endif     
+    }
+    sqlite3_free(p->aOp);
+  }
+  releaseMemArray(p->aVar, p->nVar, 1);
+  sqlite3_free(p->aLabel);
+  if( p->aMem ){
+    sqlite3_free(&p->aMem[1]);
+  }
+  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N, 1);
+  sqlite3_free(p->aColName);
+  sqlite3_free(p->zSql);
+  p->magic = VDBE_MAGIC_DEAD;
+  sqlite3_free(p);
+}
+
+/*
+** If a MoveTo operation is pending on the given cursor, then do that
+** MoveTo now.  Return an error code.  If no MoveTo is pending, this
+** routine does nothing and returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(Cursor *p){
+  if( p->deferredMoveto ){
+    int res, rc;
+#ifdef SQLITE_TEST
+    extern int sqlite3_search_count;
+#endif
+    assert( p->isTable );
+    rc = sqlite3BtreeMoveto(p->pCursor, 0, 0, p->movetoTarget, 0, &res);
+    if( rc ) return rc;
+    *p->pIncrKey = 0;
+    p->lastRowid = keyToInt(p->movetoTarget);
+    p->rowidIsValid = res==0;
+    if( res<0 ){
+      rc = sqlite3BtreeNext(p->pCursor, &res);
+      if( rc ) return rc;
+    }
+#ifdef SQLITE_TEST
+    sqlite3_search_count++;
+#endif
+    p->deferredMoveto = 0;
+    p->cacheStatus = CACHE_STALE;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialRead()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialWrite()
+**
+** encapsulate the code that serializes values for storage in SQLite
+** data and index records. Each serialized value consists of a
+** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
+** integer, stored as a varint.
+**
+** In an SQLite index record, the serial type is stored directly before
+** the blob of data that it corresponds to. In a table record, all serial
+** types are stored at the start of the record, and the blobs of data at
+** the end. Hence these functions allow the caller to handle the
+** serial-type and data blob seperately.
+**
+** The following table describes the various storage classes for data:
+**
+**   serial type        bytes of data      type
+**   --------------     ---------------    ---------------
+**      0                     0            NULL
+**      1                     1            signed integer
+**      2                     2            signed integer
+**      3                     3            signed integer
+**      4                     4            signed integer
+**      5                     6            signed integer
+**      6                     8            signed integer
+**      7                     8            IEEE float
+**      8                     0            Integer constant 0
+**      9                     0            Integer constant 1
+**     10,11                               reserved for expansion
+**    N>=12 and even       (N-12)/2        BLOB
+**    N>=13 and odd        (N-13)/2        text
+**
+** The 8 and 9 types were added in 3.3.0, file format 4.  Prior versions
+** of SQLite will not understand those serial types.
+*/
+
+/*
+** Return the serial-type for the value stored in pMem.
+*/
+SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem *pMem, int file_format){
+  int flags = pMem->flags;
+  int n;
+
+  if( flags&MEM_Null ){
+    return 0;
+  }
+  if( flags&MEM_Int ){
+    /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+#   define MAX_6BYTE ((((i64)0x00008000)<<32)-1)
+    i64 i = pMem->u.i;
+    u64 u;
+    if( file_format>=4 && (i&1)==i ){
+      return 8+i;
+    }
+    u = i<0 ? -i : i;
+    if( u<=127 ) return 1;
+    if( u<=32767 ) return 2;
+    if( u<=8388607 ) return 3;
+    if( u<=2147483647 ) return 4;
+    if( u<=MAX_6BYTE ) return 5;
+    return 6;
+  }
+  if( flags&MEM_Real ){
+    return 7;
+  }
+  assert( flags&(MEM_Str|MEM_Blob) );
+  n = pMem->n;
+  if( flags & MEM_Zero ){
+    n += pMem->u.i;
+  }
+  assert( n>=0 );
+  return ((n*2) + 12 + ((flags&MEM_Str)!=0));
+}
+
+/*
+** Return the length of the data corresponding to the supplied serial-type.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSerialTypeLen(u32 serial_type){
+  if( serial_type>=12 ){
+    return (serial_type-12)/2;
+  }else{
+    static const u8 aSize[] = { 0, 1, 2, 3, 4, 6, 8, 8, 0, 0, 0, 0 };
+    return aSize[serial_type];
+  }
+}
+
+/*
+** If we are on an architecture with mixed-endian floating 
+** points (ex: ARM7) then swap the lower 4 bytes with the 
+** upper 4 bytes.  Return the result.
+**
+** For most architectures, this is a no-op.
+**
+** (later):  It is reported to me that the mixed-endian problem
+** on ARM7 is an issue with GCC, not with the ARM7 chip.  It seems
+** that early versions of GCC stored the two words of a 64-bit
+** float in the wrong order.  And that error has been propagated
+** ever since.  The blame is not necessarily with GCC, though.
+** GCC might have just copying the problem from a prior compiler.
+** I am also told that newer versions of GCC that follow a different
+** ABI get the byte order right.
+**
+** Developers using SQLite on an ARM7 should compile and run their
+** application using -DSQLITE_DEBUG=1 at least once.  With DEBUG
+** enabled, some asserts below will ensure that the byte order of
+** floating point values is correct.
+**
+** (2007-08-30)  Frank van Vugt has studied this problem closely
+** and has send his findings to the SQLite developers.  Frank
+** writes that some Linux kernels offer floating point hardware
+** emulation that uses only 32-bit mantissas instead of a full 
+** 48-bits as required by the IEEE standard.  (This is the
+** CONFIG_FPE_FASTFPE option.)  On such systems, floating point
+** byte swapping becomes very complicated.  To avoid problems,
+** the necessary byte swapping is carried out using a 64-bit integer
+** rather than a 64-bit float.  Frank assures us that the code here
+** works for him.  We, the developers, have no way to independently
+** verify this, but Frank seems to know what he is talking about
+** so we trust him.
+*/
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+static u64 floatSwap(u64 in){
+  union {
+    u64 r;
+    u32 i[2];
+  } u;
+  u32 t;
+
+  u.r = in;
+  t = u.i[0];
+  u.i[0] = u.i[1];
+  u.i[1] = t;
+  return u.r;
+}
+# define swapMixedEndianFloat(X)  X = floatSwap(X)
+#else
+# define swapMixedEndianFloat(X)
+#endif
+
+/*
+** Write the serialized data blob for the value stored in pMem into 
+** buf. It is assumed that the caller has allocated sufficient space.
+** Return the number of bytes written.
+**
+** nBuf is the amount of space left in buf[].  nBuf must always be
+** large enough to hold the entire field.  Except, if the field is
+** a blob with a zero-filled tail, then buf[] might be just the right
+** size to hold everything except for the zero-filled tail.  If buf[]
+** is only big enough to hold the non-zero prefix, then only write that
+** prefix into buf[].  But if buf[] is large enough to hold both the
+** prefix and the tail then write the prefix and set the tail to all
+** zeros.
+**
+** Return the number of bytes actually written into buf[].  The number
+** of bytes in the zero-filled tail is included in the return value only
+** if those bytes were zeroed in buf[].
+*/ 
+SQLITE_PRIVATE int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_format){
+  u32 serial_type = sqlite3VdbeSerialType(pMem, file_format);
+  int len;
+
+  /* Integer and Real */
+  if( serial_type<=7 && serial_type>0 ){
+    u64 v;
+    int i;
+    if( serial_type==7 ){
+      assert( sizeof(v)==sizeof(pMem->r) );
+      memcpy(&v, &pMem->r, sizeof(v));
+      swapMixedEndianFloat(v);
+    }else{
+      v = pMem->u.i;
+    }
+    len = i = sqlite3VdbeSerialTypeLen(serial_type);
+    assert( len<=nBuf );
+    while( i-- ){
+      buf[i] = (v&0xFF);
+      v >>= 8;
+    }
+    return len;
+  }
+
+  /* String or blob */
+  if( serial_type>=12 ){
+    assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.i:0)
+             == sqlite3VdbeSerialTypeLen(serial_type) );
+    assert( pMem->n<=nBuf );
+    len = pMem->n;
+    memcpy(buf, pMem->z, len);
+    if( pMem->flags & MEM_Zero ){
+      len += pMem->u.i;
+      if( len>nBuf ){
+        len = nBuf;
+      }
+      memset(&buf[pMem->n], 0, len-pMem->n);
+    }
+    return len;
+  }
+
+  /* NULL or constants 0 or 1 */
+  return 0;
+}
+
+/*
+** Deserialize the data blob pointed to by buf as serial type serial_type
+** and store the result in pMem.  Return the number of bytes read.
+*/ 
+SQLITE_PRIVATE int sqlite3VdbeSerialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  switch( serial_type ){
+    case 10:   /* Reserved for future use */
+    case 11:   /* Reserved for future use */
+    case 0: {  /* NULL */
+      pMem->flags = MEM_Null;
+      break;
+    }
+    case 1: { /* 1-byte signed integer */
+      pMem->u.i = (signed char)buf[0];
+      pMem->flags = MEM_Int;
+      return 1;
+    }
+    case 2: { /* 2-byte signed integer */
+      pMem->u.i = (((signed char)buf[0])<<8) | buf[1];
+      pMem->flags = MEM_Int;
+      return 2;
+    }
+    case 3: { /* 3-byte signed integer */
+      pMem->u.i = (((signed char)buf[0])<<16) | (buf[1]<<8) | buf[2];
+      pMem->flags = MEM_Int;
+      return 3;
+    }
+    case 4: { /* 4-byte signed integer */
+      pMem->u.i = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+      pMem->flags = MEM_Int;
+      return 4;
+    }
+    case 5: { /* 6-byte signed integer */
+      u64 x = (((signed char)buf[0])<<8) | buf[1];
+      u32 y = (buf[2]<<24) | (buf[3]<<16) | (buf[4]<<8) | buf[5];
+      x = (x<<32) | y;
+      pMem->u.i = *(i64*)&x;
+      pMem->flags = MEM_Int;
+      return 6;
+    }
+    case 6:   /* 8-byte signed integer */
+    case 7: { /* IEEE floating point */
+      u64 x;
+      u32 y;
+#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
+      /* Verify that integers and floating point values use the same
+      ** byte order.  Or, that if SQLITE_MIXED_ENDIAN_64BIT_FLOAT is
+      ** defined that 64-bit floating point values really are mixed
+      ** endian.
+      */
+      static const u64 t1 = ((u64)0x3ff00000)<<32;
+      static const double r1 = 1.0;
+      u64 t2 = t1;
+      swapMixedEndianFloat(t2);
+      assert( sizeof(r1)==sizeof(t2) && memcmp(&r1, &t2, sizeof(r1))==0 );
+#endif
+
+      x = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+      y = (buf[4]<<24) | (buf[5]<<16) | (buf[6]<<8) | buf[7];
+      x = (x<<32) | y;
+      if( serial_type==6 ){
+        pMem->u.i = *(i64*)&x;
+        pMem->flags = MEM_Int;
+      }else{
+        assert( sizeof(x)==8 && sizeof(pMem->r)==8 );
+        swapMixedEndianFloat(x);
+        memcpy(&pMem->r, &x, sizeof(x));
+        pMem->flags = sqlite3IsNaN(pMem->r) ? MEM_Null : MEM_Real;
+      }
+      return 8;
+    }
+    case 8:    /* Integer 0 */
+    case 9: {  /* Integer 1 */
+      pMem->u.i = serial_type-8;
+      pMem->flags = MEM_Int;
+      return 0;
+    }
+    default: {
+      int len = (serial_type-12)/2;
+      pMem->z = (char *)buf;
+      pMem->n = len;
+      pMem->xDel = 0;
+      if( serial_type&0x01 ){
+        pMem->flags = MEM_Str | MEM_Ephem;
+      }else{
+        pMem->flags = MEM_Blob | MEM_Ephem;
+      }
+      return len;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Given the nKey-byte encoding of a record in pKey[], parse the
+** record into a UnpackedRecord structure.  Return a pointer to
+** that structure.
+**
+** The calling function might provide szSpace bytes of memory
+** space at pSpace.  This space can be used to hold the returned
+** VDbeParsedRecord structure if it is large enough.  If it is
+** not big enough, space is obtained from sqlite3_malloc().
+**
+** The returned structure should be closed by a call to
+** sqlite3VdbeDeleteUnpackedRecord().
+*/ 
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeRecordUnpack(
+  KeyInfo *pKeyInfo,     /* Information about the record format */
+  int nKey,              /* Size of the binary record */
+  const void *pKey,      /* The binary record */
+  void *pSpace,          /* Space available to hold resulting object */
+  int szSpace            /* Size of pSpace[] in bytes */
+){
+  const unsigned char *aKey = (const unsigned char *)pKey;
+  UnpackedRecord *p;
+  int nByte;
+  int i, idx, d;
+  u32 szHdr;
+  Mem *pMem;
+  
+  assert( sizeof(Mem)>sizeof(*p) );
+  nByte = sizeof(Mem)*(pKeyInfo->nField+2);
+  if( nByte>szSpace ){
+    p = sqlite3DbMallocRaw(pKeyInfo->db, nByte);
+    if( p==0 ) return 0;
+    p->needFree = 1;
+  }else{
+    p = pSpace;
+    p->needFree = 0;
+  }
+  p->pKeyInfo = pKeyInfo;
+  p->nField = pKeyInfo->nField + 1;
+  p->needDestroy = 1;
+  p->aMem = pMem = &((Mem*)p)[1];
+  idx = getVarint32(aKey, szHdr);
+  d = szHdr;
+  i = 0;
+  while( idx<szHdr && i<p->nField ){
+    u32 serial_type;
+
+    idx += getVarint32( aKey+idx, serial_type);
+    if( d>=nKey && sqlite3VdbeSerialTypeLen(serial_type)>0 ) break;
+    pMem->enc = pKeyInfo->enc;
+    pMem->db = pKeyInfo->db;
+    pMem->flags = 0;
+    pMem->zMalloc = 0;
+    d += sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
+    pMem++;
+    i++;
+  }
+  p->nField = i;
+  return (void*)p;
+}
+
+/*
+** This routine destroys a UnpackedRecord object
+*/
+SQLITE_PRIVATE void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){
+  if( p ){
+    if( p->needDestroy ){
+      int i;
+      Mem *pMem;
+      for(i=0, pMem=p->aMem; i<p->nField; i++, pMem++){
+        if( pMem->zMalloc ){
+          sqlite3VdbeMemRelease(pMem);
+        }
+      }
+    }
+    if( p->needFree ){
+      sqlite3_free(p);
+    }
+  }
+}
+
+/*
+** This function compares the two table rows or index records
+** specified by {nKey1, pKey1} and pPKey2.  It returns a negative, zero
+** or positive integer if {nKey1, pKey1} is less than, equal to or 
+** greater than pPKey2.  The {nKey1, pKey1} key must be a blob
+** created by th OP_MakeRecord opcode of the VDBE.  The pPKey2
+** key must be a parsed key such as obtained from
+** sqlite3VdbeParseRecord.
+**
+** Key1 and Key2 do not have to contain the same number of fields.
+** But if the lengths differ, Key2 must be the shorter of the two.
+**
+** Historical note: In earlier versions of this routine both Key1
+** and Key2 were blobs obtained from OP_MakeRecord.  But we found
+** that in typical use the same Key2 would be submitted multiple times
+** in a row.  So an optimization was added to parse the Key2 key
+** separately and submit the parsed version.  In this way, we avoid
+** parsing the same Key2 multiple times in a row.
+*/
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
+  int nKey1, const void *pKey1, 
+  UnpackedRecord *pPKey2
+){
+  u32 d1;            /* Offset into aKey[] of next data element */
+  u32 idx1;          /* Offset into aKey[] of next header element */
+  u32 szHdr1;        /* Number of bytes in header */
+  int i = 0;
+  int nField;
+  int rc = 0;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  KeyInfo *pKeyInfo;
+  Mem mem1;
+
+  pKeyInfo = pPKey2->pKeyInfo;
+  mem1.enc = pKeyInfo->enc;
+  mem1.db = pKeyInfo->db;
+  mem1.flags = 0;
+  mem1.zMalloc = 0;
+  
+  idx1 = getVarint32(aKey1, szHdr1);
+  d1 = szHdr1;
+  nField = pKeyInfo->nField;
+  while( idx1<szHdr1 && i<pPKey2->nField ){
+    u32 serial_type1;
+
+    /* Read the serial types for the next element in each key. */
+    idx1 += getVarint32( aKey1+idx1, serial_type1 );
+    if( d1>=nKey1 && sqlite3VdbeSerialTypeLen(serial_type1)>0 ) break;
+
+    /* Extract the values to be compared.
+    */
+    d1 += sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+
+    /* Do the comparison
+    */
+    rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
+                           i<nField ? pKeyInfo->aColl[i] : 0);
+    if( rc!=0 ){
+      break;
+    }
+    i++;
+  }
+  if( mem1.zMalloc ) sqlite3VdbeMemRelease(&mem1);
+
+  /* One of the keys ran out of fields, but all the fields up to that point
+  ** were equal. If the incrKey flag is true, then the second key is
+  ** treated as larger.
+  */
+  if( rc==0 ){
+    if( pKeyInfo->incrKey ){
+      rc = -1;
+    }else if( !pKeyInfo->prefixIsEqual ){
+      if( d1<nKey1 ){
+        rc = 1;
+      }
+    }
+  }else if( pKeyInfo->aSortOrder && i<pKeyInfo->nField
+               && pKeyInfo->aSortOrder[i] ){
+    rc = -rc;
+  }
+
+  return rc;
+}
+
+/*
+** The argument is an index entry composed using the OP_MakeRecord opcode.
+** The last entry in this record should be an integer (specifically
+** an integer rowid).  This routine returns the number of bytes in
+** that integer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxRowidLen(const u8 *aKey){
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+
+  (void)getVarint32(aKey, szHdr);
+  (void)getVarint32(&aKey[szHdr-1], typeRowid);
+  return sqlite3VdbeSerialTypeLen(typeRowid);
+}
+  
+
+/*
+** pCur points at an index entry created using the OP_MakeRecord opcode.
+** Read the rowid (the last field in the record) and store it in *rowid.
+** Return SQLITE_OK if everything works, or an error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
+  i64 nCellKey = 0;
+  int rc;
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+  u32 lenRowid;     /* Size of the rowid */
+  Mem m, v;
+
+  sqlite3BtreeKeySize(pCur, &nCellKey);
+  if( nCellKey<=0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  m.flags = 0;
+  m.db = 0;
+  m.zMalloc = 0;
+  rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
+  if( rc ){
+    return rc;
+  }
+  (void)getVarint32((u8*)m.z, szHdr);
+  (void)getVarint32((u8*)&m.z[szHdr-1], typeRowid);
+  lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
+  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
+  *rowid = v.u.i;
+  sqlite3VdbeMemRelease(&m);
+  return SQLITE_OK;
+}
+
+/*
+** Compare the key of the index entry that cursor pC is point to against
+** the key string in pKey (of length nKey).  Write into *pRes a number
+** that is negative, zero, or positive if pC is less than, equal to,
+** or greater than pKey.  Return SQLITE_OK on success.
+**
+** pKey is either created without a rowid or is truncated so that it
+** omits the rowid at the end.  The rowid at the end of the index entry
+** is ignored as well.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
+  Cursor *pC,                 /* The cursor to compare against */
+  UnpackedRecord *pUnpacked,
+  int nKey, const u8 *pKey,   /* The key to compare */
+  int *res                    /* Write the comparison result here */
+){
+  i64 nCellKey = 0;
+  int rc;
+  BtCursor *pCur = pC->pCursor;
+  int lenRowid;
+  Mem m;
+  UnpackedRecord *pRec;
+  char zSpace[200];
+
+  sqlite3BtreeKeySize(pCur, &nCellKey);
+  if( nCellKey<=0 ){
+    *res = 0;
+    return SQLITE_OK;
+  }
+  m.db = 0;
+  m.flags = 0;
+  m.zMalloc = 0;
+  rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m);
+  if( rc ){
+    return rc;
+  }
+  lenRowid = sqlite3VdbeIdxRowidLen((u8*)m.z);
+  if( !pUnpacked ){
+    pRec = sqlite3VdbeRecordUnpack(pC->pKeyInfo, nKey, pKey,
+                                zSpace, sizeof(zSpace));
+  }else{
+    pRec = pUnpacked;
+  }
+  if( pRec==0 ){
+    return SQLITE_NOMEM;
+  }
+  *res = sqlite3VdbeRecordCompare(m.n-lenRowid, m.z, pRec);
+  if( !pUnpacked ){
+    sqlite3VdbeDeleteUnpackedRecord(pRec);
+  }
+  sqlite3VdbeMemRelease(&m);
+  return SQLITE_OK;
+}
+
+/*
+** This routine sets the value to be returned by subsequent calls to
+** sqlite3_changes() on the database handle 'db'. 
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *db, int nChange){
+  assert( sqlite3_mutex_held(db->mutex) );
+  db->nChange = nChange;
+  db->nTotalChange += nChange;
+}
+
+/*
+** Set a flag in the vdbe to update the change counter when it is finalised
+** or reset.
+*/
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe *v){
+  v->changeCntOn = 1;
+}
+
+/*
+** Mark every prepared statement associated with a database connection
+** as expired.
+**
+** An expired statement means that recompilation of the statement is
+** recommend.  Statements expire when things happen that make their
+** programs obsolete.  Removing user-defined functions or collating
+** sequences, or changing an authorization function are the types of
+** things that make prepared statements obsolete.
+*/
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3 *db){
+  Vdbe *p;
+  for(p = db->pVdbe; p; p=p->pNext){
+    p->expired = 1;
+  }
+}
+
+/*
+** Return the database associated with the Vdbe.
+*/
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe *v){
+  return v->db;
+}
+
+/************** End of vdbeaux.c *********************************************/
+/************** Begin file vdbeapi.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to implement APIs that are part of the
+** VDBE.
+*/
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** The following structure contains pointers to the end points of a
+** doubly-linked list of all compiled SQL statements that may be holding
+** buffers eligible for release when the sqlite3_release_memory() interface is
+** invoked. Access to this list is protected by the SQLITE_MUTEX_STATIC_LRU2
+** mutex.
+**
+** Statements are added to the end of this list when sqlite3_reset() is
+** called. They are removed either when sqlite3_step() or sqlite3_finalize()
+** is called. When statements are added to this list, the associated 
+** register array (p->aMem[1..p->nMem]) may contain dynamic buffers that
+** can be freed using sqlite3VdbeReleaseMemory().
+**
+** When statements are added or removed from this list, the mutex
+** associated with the Vdbe being added or removed (Vdbe.db->mutex) is
+** already held. The LRU2 mutex is then obtained, blocking if necessary,
+** the linked-list pointers manipulated and the LRU2 mutex relinquished.
+*/
+struct StatementLruList {
+  Vdbe *pFirst;
+  Vdbe *pLast;
+};
+static struct StatementLruList sqlite3LruStatements;
+
+/*
+** Check that the list looks to be internally consistent. This is used
+** as part of an assert() statement as follows:
+**
+**   assert( stmtLruCheck() );
+*/
+#ifndef NDEBUG
+static int stmtLruCheck(){
+  Vdbe *p;
+  for(p=sqlite3LruStatements.pFirst; p; p=p->pLruNext){
+    assert(p->pLruNext || p==sqlite3LruStatements.pLast);
+    assert(!p->pLruNext || p->pLruNext->pLruPrev==p);
+    assert(p->pLruPrev || p==sqlite3LruStatements.pFirst);
+    assert(!p->pLruPrev || p->pLruPrev->pLruNext==p);
+  }
+  return 1;
+}
+#endif
+
+/*
+** Add vdbe p to the end of the statement lru list. It is assumed that
+** p is not already part of the list when this is called. The lru list
+** is protected by the SQLITE_MUTEX_STATIC_LRU mutex.
+*/
+static void stmtLruAdd(Vdbe *p){
+  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+
+  if( p->pLruPrev || p->pLruNext || sqlite3LruStatements.pFirst==p ){
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+    return;
+  }
+
+  assert( stmtLruCheck() );
+
+  if( !sqlite3LruStatements.pFirst ){
+    assert( !sqlite3LruStatements.pLast );
+    sqlite3LruStatements.pFirst = p;
+    sqlite3LruStatements.pLast = p;
+  }else{
+    assert( !sqlite3LruStatements.pLast->pLruNext );
+    p->pLruPrev = sqlite3LruStatements.pLast;
+    sqlite3LruStatements.pLast->pLruNext = p;
+    sqlite3LruStatements.pLast = p;
+  }
+
+  assert( stmtLruCheck() );
+
+  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+}
+
+/*
+** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is already held, remove
+** statement p from the least-recently-used statement list. If the 
+** statement is not currently part of the list, this call is a no-op.
+*/
+static void stmtLruRemoveNomutex(Vdbe *p){
+  if( p->pLruPrev || p->pLruNext || p==sqlite3LruStatements.pFirst ){
+    assert( stmtLruCheck() );
+    if( p->pLruNext ){
+      p->pLruNext->pLruPrev = p->pLruPrev;
+    }else{
+      sqlite3LruStatements.pLast = p->pLruPrev;
+    }
+    if( p->pLruPrev ){
+      p->pLruPrev->pLruNext = p->pLruNext;
+    }else{
+      sqlite3LruStatements.pFirst = p->pLruNext;
+    }
+    p->pLruNext = 0;
+    p->pLruPrev = 0;
+    assert( stmtLruCheck() );
+  }
+}
+
+/*
+** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is not held, remove
+** statement p from the least-recently-used statement list. If the 
+** statement is not currently part of the list, this call is a no-op.
+*/
+static void stmtLruRemove(Vdbe *p){
+  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+  stmtLruRemoveNomutex(p);
+  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+}
+
+/*
+** Try to release n bytes of memory by freeing buffers associated 
+** with the memory registers of currently unused vdbes.
+*/
+SQLITE_PRIVATE int sqlite3VdbeReleaseMemory(int n){
+  Vdbe *p;
+  Vdbe *pNext;
+  int nFree = 0;
+
+  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+  for(p=sqlite3LruStatements.pFirst; p && nFree<n; p=pNext){
+    pNext = p->pLruNext;
+
+    /* For each statement handle in the lru list, attempt to obtain the
+    ** associated database mutex. If it cannot be obtained, continue
+    ** to the next statement handle. It is not possible to block on
+    ** the database mutex - that could cause deadlock.
+    */
+    if( SQLITE_OK==sqlite3_mutex_try(p->db->mutex) ){
+      nFree += sqlite3VdbeReleaseBuffers(p);
+      stmtLruRemoveNomutex(p);
+      sqlite3_mutex_leave(p->db->mutex);
+    }
+  }
+  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
+
+  return nFree;
+}
+
+/*
+** Call sqlite3Reprepare() on the statement. Remove it from the
+** lru list before doing so, as Reprepare() will free all the
+** memory register buffers anyway.
+*/
+int vdbeReprepare(Vdbe *p){
+  stmtLruRemove(p);
+  return sqlite3Reprepare(p);
+}
+
+#else       /* !SQLITE_ENABLE_MEMORY_MANAGEMENT */
+  #define stmtLruRemove(x)
+  #define stmtLruAdd(x)
+  #define vdbeReprepare(x) sqlite3Reprepare(x)
+#endif
+
+
+/*
+** Return TRUE (non-zero) of the statement supplied as an argument needs
+** to be recompiled.  A statement needs to be recompiled whenever the
+** execution environment changes in a way that would alter the program
+** that sqlite3_prepare() generates.  For example, if new functions or
+** collating sequences are registered or if an authorizer function is
+** added or changed.
+*/
+SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p==0 || p->expired;
+}
+
+/*
+** The following routine destroys a virtual machine that is created by
+** the sqlite3_compile() routine. The integer returned is an SQLITE_
+** success/failure code that describes the result of executing the virtual
+** machine.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+#ifndef SQLITE_MUTEX_NOOP
+    sqlite3_mutex *mutex = v->db->mutex;
+#endif
+    sqlite3_mutex_enter(mutex);
+    stmtLruRemove(v);
+    rc = sqlite3VdbeFinalize(v);
+    sqlite3_mutex_leave(mutex);
+  }
+  return rc;
+}
+
+/*
+** Terminate the current execution of an SQL statement and reset it
+** back to its starting state so that it can be reused. A success code from
+** the prior execution is returned.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3_mutex_enter(v->db->mutex);
+    rc = sqlite3VdbeReset(v, 1);
+    stmtLruAdd(v);
+    sqlite3VdbeMakeReady(v, -1, 0, 0, 0);
+    assert( (rc & (v->db->errMask))==rc );
+    sqlite3_mutex_leave(v->db->mutex);
+  }
+  return rc;
+}
+
+/*
+** Set all the parameters in the compiled SQL statement to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt *pStmt){
+  int i;
+  int rc = SQLITE_OK;
+  Vdbe *p = (Vdbe*)pStmt;
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = ((Vdbe*)pStmt)->db->mutex;
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=0; i<p->nVar; i++){
+    sqlite3VdbeMemRelease(&p->aVar[i]);
+    p->aVar[i].flags = MEM_Null;
+  }
+  sqlite3_mutex_leave(mutex);
+  return rc;
+}
+
+
+/**************************** sqlite3_value_  *******************************
+** The following routines extract information from a Mem or sqlite3_value
+** structure.
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value *pVal){
+  Mem *p = (Mem*)pVal;
+  if( p->flags & (MEM_Blob|MEM_Str) ){
+    sqlite3VdbeMemExpandBlob(p);
+    p->flags &= ~MEM_Str;
+    p->flags |= MEM_Blob;
+    return p->z;
+  }else{
+    return sqlite3_value_text(pVal);
+  }
+}
+SQLITE_API int sqlite3_value_bytes(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF8);
+}
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API double sqlite3_value_double(sqlite3_value *pVal){
+  return sqlite3VdbeRealValue((Mem*)pVal);
+}
+SQLITE_API int sqlite3_value_int(sqlite3_value *pVal){
+  return sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
+  return sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
+  return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value* pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16BE);
+}
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16LE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_value_type(sqlite3_value* pVal){
+  return pVal->type;
+}
+
+/**************************** sqlite3_result_  *******************************
+** The following routines are used by user-defined functions to specify
+** the function result.
+*/
+SQLITE_API void sqlite3_result_blob(
+  sqlite3_context *pCtx, 
+  const void *z, 
+  int n, 
+  void (*xDel)(void *)
+){
+  assert( n>=0 );
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, 0, xDel);
+}
+SQLITE_API void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetDouble(&pCtx->s, rVal);
+}
+SQLITE_API void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF8, SQLITE_TRANSIENT);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16NATIVE, SQLITE_TRANSIENT);
+}
+#endif
+SQLITE_API void sqlite3_result_int(sqlite3_context *pCtx, int iVal){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetInt64(&pCtx->s, (i64)iVal);
+}
+SQLITE_API void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetInt64(&pCtx->s, iVal);
+}
+SQLITE_API void sqlite3_result_null(sqlite3_context *pCtx){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetNull(&pCtx->s);
+}
+SQLITE_API void sqlite3_result_text(
+  sqlite3_context *pCtx, 
+  const char *z, 
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF8, xDel);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_text16(
+  sqlite3_context *pCtx, 
+  const void *z, 
+  int n, 
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16NATIVE, xDel);
+}
+SQLITE_API void sqlite3_result_text16be(
+  sqlite3_context *pCtx, 
+  const void *z, 
+  int n, 
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16BE, xDel);
+}
+SQLITE_API void sqlite3_result_text16le(
+  sqlite3_context *pCtx, 
+  const void *z, 
+  int n, 
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16LE, xDel);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemCopy(&pCtx->s, pValue);
+}
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetZeroBlob(&pCtx->s, n);
+}
+SQLITE_API void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
+  pCtx->isError = errCode;
+}
+
+/* Force an SQLITE_TOOBIG error. */
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context *pCtx){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  pCtx->isError = SQLITE_TOOBIG;
+  sqlite3VdbeMemSetStr(&pCtx->s, "string or blob too big", -1, 
+                       SQLITE_UTF8, SQLITE_STATIC);
+}
+
+/* An SQLITE_NOMEM error. */
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context *pCtx){
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  sqlite3VdbeMemSetNull(&pCtx->s);
+  pCtx->isError = SQLITE_NOMEM;
+  pCtx->s.db->mallocFailed = 1;
+}
+
+/*
+** Execute the statement pStmt, either until a row of data is ready, the
+** statement is completely executed or an error occurs.
+**
+** This routine implements the bulk of the logic behind the sqlite_step()
+** API.  The only thing omitted is the automatic recompile if a 
+** schema change has occurred.  That detail is handled by the
+** outer sqlite3_step() wrapper procedure.
+*/
+static int sqlite3Step(Vdbe *p){
+  sqlite3 *db;
+  int rc;
+
+  assert(p);
+  if( p->magic!=VDBE_MAGIC_RUN ){
+    return SQLITE_MISUSE;
+  }
+
+  /* Assert that malloc() has not failed */
+  db = p->db;
+  assert( !db->mallocFailed );
+
+  if( p->aborted ){
+    return SQLITE_ABORT;
+  }
+  if( p->pc<=0 && p->expired ){
+    if( p->rc==SQLITE_OK ){
+      p->rc = SQLITE_SCHEMA;
+    }
+    rc = SQLITE_ERROR;
+    goto end_of_step;
+  }
+  if( sqlite3SafetyOn(db) ){
+    p->rc = SQLITE_MISUSE;
+    return SQLITE_MISUSE;
+  }
+  if( p->pc<0 ){
+    /* If there are no other statements currently running, then
+    ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
+    ** from interrupting a statement that has not yet started.
+    */
+    if( db->activeVdbeCnt==0 ){
+      db->u1.isInterrupted = 0;
+    }
+
+#ifndef SQLITE_OMIT_TRACE
+    if( db->xProfile && !db->init.busy ){
+      double rNow;
+      sqlite3OsCurrentTime(db->pVfs, &rNow);
+      p->startTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0;
+    }
+#endif
+
+    db->activeVdbeCnt++;
+    p->pc = 0;
+    stmtLruRemove(p);
+  }
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( p->explain ){
+    rc = sqlite3VdbeList(p);
+  }else
+#endif /* SQLITE_OMIT_EXPLAIN */
+  {
+    rc = sqlite3VdbeExec(p);
+  }
+
+  if( sqlite3SafetyOff(db) ){
+    rc = SQLITE_MISUSE;
+  }
+
+#ifndef SQLITE_OMIT_TRACE
+  /* Invoke the profile callback if there is one
+  */
+  if( rc!=SQLITE_ROW && db->xProfile && !db->init.busy && p->nOp>0
+           && p->aOp[0].opcode==OP_Trace && p->aOp[0].p4.z!=0 ){
+    double rNow;
+    u64 elapseTime;
+
+    sqlite3OsCurrentTime(db->pVfs, &rNow);
+    elapseTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0 - p->startTime;
+    db->xProfile(db->pProfileArg, p->aOp[0].p4.z, elapseTime);
+  }
+#endif
+
+  sqlite3Error(p->db, rc, 0);
+  p->rc = sqlite3ApiExit(p->db, p->rc);
+end_of_step:
+  assert( (rc&0xff)==rc );
+  if( p->zSql && (rc&0xff)<SQLITE_ROW ){
+    /* This behavior occurs if sqlite3_prepare_v2() was used to build
+    ** the prepared statement.  Return error codes directly */
+    sqlite3Error(p->db, p->rc, 0);
+    return p->rc;
+  }else{
+    /* This is for legacy sqlite3_prepare() builds and when the code
+    ** is SQLITE_ROW or SQLITE_DONE */
+    return rc;
+  }
+}
+
+/*
+** This is the top-level implementation of sqlite3_step().  Call
+** sqlite3Step() to do most of the work.  If a schema error occurs,
+** call sqlite3Reprepare() and try again.
+*/
+#ifdef SQLITE_OMIT_PARSER
+SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
+  int rc = SQLITE_MISUSE;
+  if( pStmt ){
+    Vdbe *v;
+    v = (Vdbe*)pStmt;
+    sqlite3_mutex_enter(v->db->mutex);
+    rc = sqlite3Step(v);
+    sqlite3_mutex_leave(v->db->mutex);
+  }
+  return rc;
+}
+#else
+SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
+  int rc = SQLITE_MISUSE;
+  if( pStmt ){
+    int cnt = 0;
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3 *db = v->db;
+    sqlite3_mutex_enter(db->mutex);
+    while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
+           && cnt++ < 5
+           && vdbeReprepare(v) ){
+      sqlite3_reset(pStmt);
+      v->expired = 0;
+    }
+    if( rc==SQLITE_SCHEMA && v->zSql && db->pErr ){
+      /* This case occurs after failing to recompile an sql statement. 
+      ** The error message from the SQL compiler has already been loaded 
+      ** into the database handle. This block copies the error message 
+      ** from the database handle into the statement and sets the statement
+      ** program counter to 0 to ensure that when the statement is 
+      ** finalized or reset the parser error message is available via
+      ** sqlite3_errmsg() and sqlite3_errcode().
+      */
+      const char *zErr = (const char *)sqlite3_value_text(db->pErr); 
+      sqlite3_free(v->zErrMsg);
+      if( !db->mallocFailed ){
+        v->zErrMsg = sqlite3DbStrDup(db, zErr);
+      } else {
+        v->zErrMsg = 0;
+        v->rc = SQLITE_NOMEM;
+      }
+    }
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3_mutex_leave(db->mutex);
+  }
+  return rc;
+}
+#endif
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context *p){
+  assert( p && p->pFunc );
+  return p->pFunc->pUserData;
+}
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
+  assert( p && p->pFunc );
+  return p->s.db;
+}
+
+/*
+** The following is the implementation of an SQL function that always
+** fails with an error message stating that the function is used in the
+** wrong context.  The sqlite3_overload_function() API might construct
+** SQL function that use this routine so that the functions will exist
+** for name resolution but are actually overloaded by the xFindFunction
+** method of virtual tables.
+*/
+SQLITE_PRIVATE void sqlite3InvalidFunction(
+  sqlite3_context *context,  /* The function calling context */
+  int argc,                  /* Number of arguments to the function */
+  sqlite3_value **argv       /* Value of each argument */
+){
+  const char *zName = context->pFunc->zName;
+  char *zErr;
+  zErr = sqlite3MPrintf(0,
+      "unable to use function %s in the requested context", zName);
+  sqlite3_result_error(context, zErr, -1);
+  sqlite3_free(zErr);
+}
+
+/*
+** Allocate or return the aggregate context for a user function.  A new
+** context is allocated on the first call.  Subsequent calls return the
+** same context that was returned on prior calls.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
+  Mem *pMem;
+  assert( p && p->pFunc && p->pFunc->xStep );
+  assert( sqlite3_mutex_held(p->s.db->mutex) );
+  pMem = p->pMem;
+  if( (pMem->flags & MEM_Agg)==0 ){
+    if( nByte==0 ){
+      sqlite3VdbeMemReleaseExternal(pMem);
+      pMem->flags = MEM_Null;
+      pMem->z = 0;
+    }else{
+      sqlite3VdbeMemGrow(pMem, nByte, 0);
+      pMem->flags = MEM_Agg;
+      pMem->u.pDef = p->pFunc;
+      if( pMem->z ){
+        memset(pMem->z, 0, nByte);
+      }
+    }
+  }
+  return (void*)pMem->z;
+}
+
+/*
+** Return the auxilary data pointer, if any, for the iArg'th argument to
+** the user-function defined by pCtx.
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){
+  VdbeFunc *pVdbeFunc;
+
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  pVdbeFunc = pCtx->pVdbeFunc;
+  if( !pVdbeFunc || iArg>=pVdbeFunc->nAux || iArg<0 ){
+    return 0;
+  }
+  return pVdbeFunc->apAux[iArg].pAux;
+}
+
+/*
+** Set the auxilary data pointer and delete function, for the iArg'th
+** argument to the user-function defined by pCtx. Any previous value is
+** deleted by calling the delete function specified when it was set.
+*/
+SQLITE_API void sqlite3_set_auxdata(
+  sqlite3_context *pCtx, 
+  int iArg, 
+  void *pAux, 
+  void (*xDelete)(void*)
+){
+  struct AuxData *pAuxData;
+  VdbeFunc *pVdbeFunc;
+  if( iArg<0 ) goto failed;
+
+  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
+  pVdbeFunc = pCtx->pVdbeFunc;
+  if( !pVdbeFunc || pVdbeFunc->nAux<=iArg ){
+    int nAux = (pVdbeFunc ? pVdbeFunc->nAux : 0);
+    int nMalloc = sizeof(VdbeFunc) + sizeof(struct AuxData)*iArg;
+    pVdbeFunc = sqlite3DbRealloc(pCtx->s.db, pVdbeFunc, nMalloc);
+    if( !pVdbeFunc ){
+      goto failed;
+    }
+    pCtx->pVdbeFunc = pVdbeFunc;
+    memset(&pVdbeFunc->apAux[nAux], 0, sizeof(struct AuxData)*(iArg+1-nAux));
+    pVdbeFunc->nAux = iArg+1;
+    pVdbeFunc->pFunc = pCtx->pFunc;
+  }
+
+  pAuxData = &pVdbeFunc->apAux[iArg];
+  if( pAuxData->pAux && pAuxData->xDelete ){
+    pAuxData->xDelete(pAuxData->pAux);
+  }
+  pAuxData->pAux = pAux;
+  pAuxData->xDelete = xDelete;
+  return;
+
+failed:
+  if( xDelete ){
+    xDelete(pAux);
+  }
+}
+
+/*
+** Return the number of times the Step function of a aggregate has been 
+** called.
+**
+** This function is deprecated.  Do not use it for new code.  It is
+** provide only to avoid breaking legacy code.  New aggregate function
+** implementations should keep their own counts within their aggregate
+** context.
+*/
+SQLITE_API int sqlite3_aggregate_count(sqlite3_context *p){
+  assert( p && p->pFunc && p->pFunc->xStep );
+  return p->pMem->n;
+}
+
+/*
+** Return the number of columns in the result set for the statement pStmt.
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  return pVm ? pVm->nResColumn : 0;
+}
+
+/*
+** Return the number of values available from the current row of the
+** currently executing statement pStmt.
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  if( pVm==0 || pVm->pResultSet==0 ) return 0;
+  return pVm->nResColumn;
+}
+
+
+/*
+** Check to see if column iCol of the given statement is valid.  If
+** it is, return a pointer to the Mem for the value of that column.
+** If iCol is not valid, return a pointer to a Mem which has a value
+** of NULL.
+*/
+static Mem *columnMem(sqlite3_stmt *pStmt, int i){
+  Vdbe *pVm;
+  int vals;
+  Mem *pOut;
+
+  pVm = (Vdbe *)pStmt;
+  if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
+    sqlite3_mutex_enter(pVm->db->mutex);
+    vals = sqlite3_data_count(pStmt);
+    pOut = &pVm->pResultSet[i];
+  }else{
+    static const Mem nullMem = {{0}, 0.0, 0, "", 0, MEM_Null, SQLITE_NULL, 0, 0, 0 };
+    if( pVm->db ){
+      sqlite3_mutex_enter(pVm->db->mutex);
+      sqlite3Error(pVm->db, SQLITE_RANGE, 0);
+    }
+    pOut = (Mem*)&nullMem;
+  }
+  return pOut;
+}
+
+/*
+** This function is called after invoking an sqlite3_value_XXX function on a 
+** column value (i.e. a value returned by evaluating an SQL expression in the
+** select list of a SELECT statement) that may cause a malloc() failure. If 
+** malloc() has failed, the threads mallocFailed flag is cleared and the result
+** code of statement pStmt set to SQLITE_NOMEM.
+**
+** Specifically, this is called from within:
+**
+**     sqlite3_column_int()
+**     sqlite3_column_int64()
+**     sqlite3_column_text()
+**     sqlite3_column_text16()
+**     sqlite3_column_real()
+**     sqlite3_column_bytes()
+**     sqlite3_column_bytes16()
+**
+** But not for sqlite3_column_blob(), which never calls malloc().
+*/
+static void columnMallocFailure(sqlite3_stmt *pStmt)
+{
+  /* If malloc() failed during an encoding conversion within an
+  ** sqlite3_column_XXX API, then set the return code of the statement to
+  ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
+  ** and _finalize() will return NOMEM.
+  */
+  Vdbe *p = (Vdbe *)pStmt;
+  if( p ){
+    p->rc = sqlite3ApiExit(p->db, p->rc);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+}
+
+/**************************** sqlite3_column_  *******************************
+** The following routines are used to access elements of the current row
+** in the result set.
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt *pStmt, int i){
+  const void *val;
+  val = sqlite3_value_blob( columnMem(pStmt,i) );
+  /* Even though there is no encoding conversion, value_blob() might
+  ** need to call malloc() to expand the result of a zeroblob() 
+  ** expression. 
+  */
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API double sqlite3_column_double(sqlite3_stmt *pStmt, int i){
+  double val = sqlite3_value_double( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_int(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_int( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite_int64 sqlite3_column_int64(sqlite3_stmt *pStmt, int i){
+  sqlite_int64 val = sqlite3_value_int64( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt *pStmt, int i){
+  const unsigned char *val = sqlite3_value_text( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt *pStmt, int i){
+  sqlite3_value *pOut = columnMem(pStmt, i);
+  columnMallocFailure(pStmt);
+  return pOut;
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt *pStmt, int i){
+  const void *val = sqlite3_value_text16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_column_type(sqlite3_stmt *pStmt, int i){
+  int iType = sqlite3_value_type( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return iType;
+}
+
+/* The following function is experimental and subject to change or
+** removal */
+/*int sqlite3_column_numeric_type(sqlite3_stmt *pStmt, int i){
+**  return sqlite3_value_numeric_type( columnMem(pStmt,i) );
+**}
+*/
+
+/*
+** Convert the N-th element of pStmt->pColName[] into a string using
+** xFunc() then return that string.  If N is out of range, return 0.
+**
+** There are up to 5 names for each column.  useType determines which
+** name is returned.  Here are the names:
+**
+**    0      The column name as it should be displayed for output
+**    1      The datatype name for the column
+**    2      The name of the database that the column derives from
+**    3      The name of the table that the column derives from
+**    4      The name of the table column that the result column derives from
+**
+** If the result is not a simple column reference (if it is an expression
+** or a constant) then useTypes 2, 3, and 4 return NULL.
+*/
+static const void *columnName(
+  sqlite3_stmt *pStmt,
+  int N,
+  const void *(*xFunc)(Mem*),
+  int useType
+){
+  const void *ret = 0;
+  Vdbe *p = (Vdbe *)pStmt;
+  int n;
+  
+
+  if( p!=0 ){
+    n = sqlite3_column_count(pStmt);
+    if( N<n && N>=0 ){
+      N += useType*n;
+      sqlite3_mutex_enter(p->db->mutex);
+      ret = xFunc(&p->aColName[N]);
+
+      /* A malloc may have failed inside of the xFunc() call. If this
+      ** is the case, clear the mallocFailed flag and return NULL.
+      */
+      if( p->db && p->db->mallocFailed ){
+        p->db->mallocFailed = 0;
+        ret = 0;
+      }
+      sqlite3_mutex_leave(p->db->mutex);
+    }
+  }
+  return ret;
+}
+
+/*
+** Return the name of the Nth column of the result set returned by SQL
+** statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text, COLNAME_NAME);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text16, COLNAME_NAME);
+}
+#endif
+
+/*
+** Constraint:  If you have ENABLE_COLUMN_METADATA then you must
+** not define OMIT_DECLTYPE.
+*/
+#if defined(SQLITE_OMIT_DECLTYPE) && defined(SQLITE_ENABLE_COLUMN_METADATA)
+# error "Must not define both SQLITE_OMIT_DECLTYPE \
+         and SQLITE_ENABLE_COLUMN_METADATA"
+#endif
+
+#ifndef SQLITE_OMIT_DECLTYPE
+/*
+** Return the column declaration type (if applicable) of the 'i'th column
+** of the result set of SQL statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text, COLNAME_DECLTYPE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text16, COLNAME_DECLTYPE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_DECLTYPE */
+
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+/*
+** Return the name of the database from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unabiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text, COLNAME_DATABASE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text16, COLNAME_DATABASE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unabiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text, COLNAME_TABLE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text16, COLNAME_TABLE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table column from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unabiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text, COLNAME_COLUMN);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(
+      pStmt, N, (const void*(*)(Mem*))sqlite3_value_text16, COLNAME_COLUMN);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_ENABLE_COLUMN_METADATA */
+
+
+/******************************* sqlite3_bind_  ***************************
+** 
+** Routines used to attach values to wildcards in a compiled SQL statement.
+*/
+/*
+** Unbind the value bound to variable i in virtual machine p. This is the 
+** the same as binding a NULL value to the column. If the "i" parameter is
+** out of range, then SQLITE_RANGE is returned. Othewise SQLITE_OK.
+**
+** The error code stored in database p->db is overwritten with the return
+** value in any case.
+*/
+static int vdbeUnbind(Vdbe *p, int i){
+  Mem *pVar;
+  if( p==0 || p->magic!=VDBE_MAGIC_RUN || p->pc>=0 ){
+    if( p ) sqlite3Error(p->db, SQLITE_MISUSE, 0);
+    return SQLITE_MISUSE;
+  }
+  if( i<1 || i>p->nVar ){
+    sqlite3Error(p->db, SQLITE_RANGE, 0);
+    return SQLITE_RANGE;
+  }
+  i--;
+  pVar = &p->aVar[i];
+  sqlite3VdbeMemRelease(pVar);
+  pVar->flags = MEM_Null;
+  sqlite3Error(p->db, SQLITE_OK, 0);
+  return SQLITE_OK;
+}
+
+/*
+** Bind a text or BLOB value.
+*/
+static int bindText(
+  sqlite3_stmt *pStmt,   /* The statement to bind against */
+  int i,                 /* Index of the parameter to bind */
+  const void *zData,     /* Pointer to the data to be bound */
+  int nData,             /* Number of bytes of data to be bound */
+  void (*xDel)(void*),   /* Destructor for the data */
+  int encoding           /* Encoding for the data */
+){
+  Vdbe *p = (Vdbe *)pStmt;
+  Mem *pVar;
+  int rc;
+
+  if( p==0 ){
+    return SQLITE_MISUSE;
+  }
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  if( rc==SQLITE_OK && zData!=0 ){
+    pVar = &p->aVar[i-1];
+    rc = sqlite3VdbeMemSetStr(pVar, zData, nData, encoding, xDel);
+    if( rc==SQLITE_OK && encoding!=0 ){
+      rc = sqlite3VdbeChangeEncoding(pVar, ENC(p->db));
+    }
+    sqlite3Error(p->db, rc, 0);
+    rc = sqlite3ApiExit(p->db, rc);
+  }
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+
+
+/*
+** Bind a blob value to an SQL statement variable.
+*/
+SQLITE_API int sqlite3_bind_blob(
+  sqlite3_stmt *pStmt, 
+  int i, 
+  const void *zData, 
+  int nData, 
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, nData, xDel, 0);
+}
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt *pStmt, int i, double rValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  if( rc==SQLITE_OK ){
+    sqlite3VdbeMemSetDouble(&p->aVar[i-1], rValue);
+  }
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt *p, int i, int iValue){
+  return sqlite3_bind_int64(p, i, (i64)iValue);
+}
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt *pStmt, int i, sqlite_int64 iValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  if( rc==SQLITE_OK ){
+    sqlite3VdbeMemSetInt64(&p->aVar[i-1], iValue);
+  }
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt *pStmt, int i){
+  int rc;
+  Vdbe *p = (Vdbe*)pStmt;
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+SQLITE_API int sqlite3_bind_text( 
+  sqlite3_stmt *pStmt, 
+  int i, 
+  const char *zData, 
+  int nData, 
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF8);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_bind_text16(
+  sqlite3_stmt *pStmt, 
+  int i, 
+  const void *zData, 
+  int nData, 
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF16NATIVE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3VdbeMemCopy(&p->aVar[i-1], pValue);
+  }
+  rc = sqlite3ApiExit(p->db, rc);
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  sqlite3_mutex_enter(p->db->mutex);
+  rc = vdbeUnbind(p, i);
+  if( rc==SQLITE_OK ){
+    sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
+  }
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+
+/*
+** Return the number of wildcards that can be potentially bound to.
+** This routine is added to support DBD::SQLite.  
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p ? p->nVar : 0;
+}
+
+/*
+** Create a mapping from variable numbers to variable names
+** in the Vdbe.azVar[] array, if such a mapping does not already
+** exist.
+*/
+static void createVarMap(Vdbe *p){
+  if( !p->okVar ){
+    sqlite3_mutex_enter(p->db->mutex);
+    if( !p->okVar ){
+      int j;
+      Op *pOp;
+      for(j=0, pOp=p->aOp; j<p->nOp; j++, pOp++){
+        if( pOp->opcode==OP_Variable ){
+          assert( pOp->p1>0 && pOp->p1<=p->nVar );
+          p->azVar[pOp->p1-1] = pOp->p4.z;
+        }
+      }
+      p->okVar = 1;
+    }
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+}
+
+/*
+** Return the name of a wildcard parameter.  Return NULL if the index
+** is out of range or if the wildcard is unnamed.
+**
+** The result is always UTF-8.
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
+  Vdbe *p = (Vdbe*)pStmt;
+  if( p==0 || i<1 || i>p->nVar ){
+    return 0;
+  }
+  createVarMap(p);
+  return p->azVar[i-1];
+}
+
+/*
+** Given a wildcard parameter name, return the index of the variable
+** with that name.  If there is no variable with the given name,
+** return 0.
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
+  Vdbe *p = (Vdbe*)pStmt;
+  int i;
+  if( p==0 ){
+    return 0;
+  }
+  createVarMap(p); 
+  if( zName ){
+    for(i=0; i<p->nVar; i++){
+      const char *z = p->azVar[i];
+      if( z && strcmp(z,zName)==0 ){
+        return i+1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Transfer all bindings from the first statement over to the second.
+** If the two statements contain a different number of bindings, then
+** an SQLITE_ERROR is returned.
+*/
+SQLITE_API int sqlite3_transfer_bindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  int i, rc = SQLITE_OK;
+  if( (pFrom->magic!=VDBE_MAGIC_RUN && pFrom->magic!=VDBE_MAGIC_HALT)
+    || (pTo->magic!=VDBE_MAGIC_RUN && pTo->magic!=VDBE_MAGIC_HALT)
+    || pTo->db!=pFrom->db ){
+    return SQLITE_MISUSE;
+  }
+  if( pFrom->nVar!=pTo->nVar ){
+    return SQLITE_ERROR;
+  }
+  sqlite3_mutex_enter(pTo->db->mutex);
+  for(i=0; rc==SQLITE_OK && i<pFrom->nVar; i++){
+    sqlite3VdbeMemMove(&pTo->aVar[i], &pFrom->aVar[i]);
+  }
+  sqlite3_mutex_leave(pTo->db->mutex);
+  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+  return rc;
+}
+
+/*
+** Return the sqlite3* database handle to which the prepared statement given
+** in the argument belongs.  This is the same database handle that was
+** the first argument to the sqlite3_prepare() that was used to create
+** the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->db : 0;
+}
+
+/************** End of vdbeapi.c *********************************************/
+/************** Begin file vdbe.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** The code in this file implements execution method of the 
+** Virtual Database Engine (VDBE).  A separate file ("vdbeaux.c")
+** handles housekeeping details such as creating and deleting
+** VDBE instances.  This file is solely interested in executing
+** the VDBE program.
+**
+** In the external interface, an "sqlite3_stmt*" is an opaque pointer
+** to a VDBE.
+**
+** The SQL parser generates a program which is then executed by
+** the VDBE to do the work of the SQL statement.  VDBE programs are 
+** similar in form to assembly language.  The program consists of
+** a linear sequence of operations.  Each operation has an opcode 
+** and 5 operands.  Operands P1, P2, and P3 are integers.  Operand P4 
+** is a null-terminated string.  Operand P5 is an unsigned character.
+** Few opcodes use all 5 operands.
+**
+** Computation results are stored on a set of registers numbered beginning
+** with 1 and going up to Vdbe.nMem.  Each register can store
+** either an integer, a null-terminated string, a floating point
+** number, or the SQL "NULL" value.  An inplicit conversion from one
+** type to the other occurs as necessary.
+** 
+** Most of the code in this file is taken up by the sqlite3VdbeExec()
+** function which does the work of interpreting a VDBE program.
+** But other routines are also provided to help in building up
+** a program instruction by instruction.
+**
+** Various scripts scan this source file in order to generate HTML
+** documentation, headers files, or other derived files.  The formatting
+** of the code in this file is, therefore, important.  See other comments
+** in this file for details.  If in doubt, do not deviate from existing
+** commenting and indentation practices when changing or adding code.
+**
+** $Id: vdbe.c,v 1.740 2008/05/13 13:27:34 drh Exp $
+*/
+
+/*
+** The following global variable is incremented every time a cursor
+** moves, either by the OP_MoveXX, OP_Next, or OP_Prev opcodes.  The test
+** procedures use this information to make sure that indices are
+** working correctly.  This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_search_count = 0;
+#endif
+
+/*
+** When this global variable is positive, it gets decremented once before
+** each instruction in the VDBE.  When reaches zero, the u1.isInterrupted
+** field of the sqlite3 structure is set in order to simulate and interrupt.
+**
+** This facility is used for testing purposes only.  It does not function
+** in an ordinary build.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_interrupt_count = 0;
+#endif
+
+/*
+** The next global variable is incremented each type the OP_Sort opcode
+** is executed.  The test procedures use this information to make sure that
+** sorting is occurring or not occuring at appropriate times.   This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_sort_count = 0;
+#endif
+
+/*
+** The next global variable records the size of the largest MEM_Blob
+** or MEM_Str that has been used by a VDBE opcode.  The test procedures
+** use this information to make sure that the zero-blob functionality
+** is working correctly.   This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_max_blobsize = 0;
+static void updateMaxBlobsize(Mem *p){
+  if( (p->flags & (MEM_Str|MEM_Blob))!=0 && p->n>sqlite3_max_blobsize ){
+    sqlite3_max_blobsize = p->n;
+  }
+}
+#endif
+
+/*
+** Test a register to see if it exceeds the current maximum blob size.
+** If it does, record the new maximum blob size.
+*/
+#if defined(SQLITE_TEST) && !defined(SQLITE_OMIT_BUILTIN_TEST)
+# define UPDATE_MAX_BLOBSIZE(P)  updateMaxBlobsize(P)
+#else
+# define UPDATE_MAX_BLOBSIZE(P)
+#endif
+
+/*
+** Release the memory associated with a register.  This
+** leaves the Mem.flags field in an inconsistent state.
+*/
+#define Release(P) if((P)->flags&MEM_Dyn){ sqlite3VdbeMemRelease(P); }
+
+/*
+** Convert the given register into a string if it isn't one
+** already. Return non-zero if a malloc() fails.
+*/
+#define Stringify(P, enc) \
+   if(((P)->flags&(MEM_Str|MEM_Blob))==0 && sqlite3VdbeMemStringify(P,enc)) \
+     { goto no_mem; }
+
+/*
+** An ephemeral string value (signified by the MEM_Ephem flag) contains
+** a pointer to a dynamically allocated string where some other entity
+** is responsible for deallocating that string.  Because the register
+** does not control the string, it might be deleted without the register
+** knowing it.
+**
+** This routine converts an ephemeral string into a dynamically allocated
+** string that the register itself controls.  In other words, it
+** converts an MEM_Ephem string into an MEM_Dyn string.
+*/
+#define Deephemeralize(P) \
+   if( ((P)->flags&MEM_Ephem)!=0 \
+       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
+
+/*
+** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
+** P if required.
+*/
+#define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+
+/*
+** Argument pMem points at a regiser that will be passed to a
+** user-defined function or returned to the user as the result of a query.
+** The second argument, 'db_enc' is the text encoding used by the vdbe for
+** register variables.  This routine sets the pMem->enc and pMem->type
+** variables used by the sqlite3_value_*() routines.
+*/
+#define storeTypeInfo(A,B) _storeTypeInfo(A)
+static void _storeTypeInfo(Mem *pMem){
+  int flags = pMem->flags;
+  if( flags & MEM_Null ){
+    pMem->type = SQLITE_NULL;
+  }
+  else if( flags & MEM_Int ){
+    pMem->type = SQLITE_INTEGER;
+  }
+  else if( flags & MEM_Real ){
+    pMem->type = SQLITE_FLOAT;
+  }
+  else if( flags & MEM_Str ){
+    pMem->type = SQLITE_TEXT;
+  }else{
+    pMem->type = SQLITE_BLOB;
+  }
+}
+
+/*
+** Properties of opcodes.  The OPFLG_INITIALIZER macro is
+** created by mkopcodeh.awk during compilation.  Data is obtained
+** from the comments following the "case OP_xxxx:" statements in
+** this file.  
+*/
+static unsigned char opcodeProperty[] = OPFLG_INITIALIZER;
+
+/*
+** Return true if an opcode has any of the OPFLG_xxx properties
+** specified by mask.
+*/
+SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int opcode, int mask){
+  assert( opcode>0 && opcode<sizeof(opcodeProperty) );
+  return (opcodeProperty[opcode]&mask)!=0;
+}
+
+/*
+** Allocate cursor number iCur.  Return a pointer to it.  Return NULL
+** if we run out of memory.
+*/
+static Cursor *allocateCursor(
+  Vdbe *p, 
+  int iCur, 
+  Op *pOp,
+  int iDb, 
+  int isBtreeCursor
+){
+  /* Find the memory cell that will be used to store the blob of memory
+  ** required for this Cursor structure. It is convenient to use a 
+  ** vdbe memory cell to manage the memory allocation required for a
+  ** Cursor structure for the following reasons:
+  **
+  **   * Sometimes cursor numbers are used for a couple of different
+  **     purposes in a vdbe program. The different uses might require
+  **     different sized allocations. Memory cells provide growable
+  **     allocations.
+  **
+  **   * When using ENABLE_MEMORY_MANAGEMENT, memory cell buffers can
+  **     be freed lazily via the sqlite3_release_memory() API. This
+  **     minimizes the number of malloc calls made by the system.
+  **
+  ** Memory cells for cursors are allocated at the top of the address
+  ** space. Memory cell (p->nMem) corresponds to cursor 0. Space for
+  ** cursor 1 is managed by memory cell (p->nMem-1), etc.
+  */
+  Mem *pMem = &p->aMem[p->nMem-iCur];
+
+  int nByte;
+  Cursor *pCx = 0;
+  /* If the opcode of pOp is OP_SetNumColumns, then pOp->p2 contains
+  ** the number of fields in the records contained in the table or
+  ** index being opened. Use this to reserve space for the 
+  ** Cursor.aType[] array.
+  */
+  int nField = 0;
+  if( pOp->opcode==OP_SetNumColumns || pOp->opcode==OP_OpenEphemeral ){
+    nField = pOp->p2;
+  }
+  nByte = 
+      sizeof(Cursor) + 
+      (isBtreeCursor?sqlite3BtreeCursorSize():0) + 
+      2*nField*sizeof(u32);
+
+  assert( iCur<p->nCursor );
+  if( p->apCsr[iCur] ){
+    sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
+    p->apCsr[iCur] = 0;
+  }
+  if( SQLITE_OK==sqlite3VdbeMemGrow(pMem, nByte, 0) ){
+    p->apCsr[iCur] = pCx = (Cursor *)pMem->z;
+    memset(pMem->z, 0, nByte);
+    pCx->iDb = iDb;
+    pCx->nField = nField;
+    if( nField ){
+      pCx->aType = (u32 *)&pMem->z[sizeof(Cursor)];
+    }
+    if( isBtreeCursor ){
+      pCx->pCursor = (BtCursor *)&pMem->z[sizeof(Cursor)+2*nField*sizeof(u32)];
+    }
+  }
+  return pCx;
+}
+
+/*
+** Try to convert a value into a numeric representation if we can
+** do so without loss of information.  In other words, if the string
+** looks like a number, convert it into a number.  If it does not
+** look like a number, leave it alone.
+*/
+static void applyNumericAffinity(Mem *pRec){
+  if( (pRec->flags & (MEM_Real|MEM_Int))==0 ){
+    int realnum;
+    sqlite3VdbeMemNulTerminate(pRec);
+    if( (pRec->flags&MEM_Str)
+         && sqlite3IsNumber(pRec->z, &realnum, pRec->enc) ){
+      i64 value;
+      sqlite3VdbeChangeEncoding(pRec, SQLITE_UTF8);
+      if( !realnum && sqlite3Atoi64(pRec->z, &value) ){
+        pRec->u.i = value;
+        MemSetTypeFlag(pRec, MEM_Int);
+      }else{
+        sqlite3VdbeMemRealify(pRec);
+      }
+    }
+  }
+}
+
+/*
+** Processing is determine by the affinity parameter:
+**
+** SQLITE_AFF_INTEGER:
+** SQLITE_AFF_REAL:
+** SQLITE_AFF_NUMERIC:
+**    Try to convert pRec to an integer representation or a 
+**    floating-point representation if an integer representation
+**    is not possible.  Note that the integer representation is
+**    always preferred, even if the affinity is REAL, because
+**    an integer representation is more space efficient on disk.
+**
+** SQLITE_AFF_TEXT:
+**    Convert pRec to a text representation.
+**
+** SQLITE_AFF_NONE:
+**    No-op.  pRec is unchanged.
+*/
+static void applyAffinity(
+  Mem *pRec,          /* The value to apply affinity to */
+  char affinity,      /* The affinity to be applied */
+  u8 enc              /* Use this text encoding */
+){
+  if( affinity==SQLITE_AFF_TEXT ){
+    /* Only attempt the conversion to TEXT if there is an integer or real
+    ** representation (blob and NULL do not get converted) but no string
+    ** representation.
+    */
+    if( 0==(pRec->flags&MEM_Str) && (pRec->flags&(MEM_Real|MEM_Int)) ){
+      sqlite3VdbeMemStringify(pRec, enc);
+    }
+    pRec->flags &= ~(MEM_Real|MEM_Int);
+  }else if( affinity!=SQLITE_AFF_NONE ){
+    assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
+             || affinity==SQLITE_AFF_NUMERIC );
+    applyNumericAffinity(pRec);
+    if( pRec->flags & MEM_Real ){
+      sqlite3VdbeIntegerAffinity(pRec);
+    }
+  }
+}
+
+/*
+** Try to convert the type of a function argument or a result column
+** into a numeric representation.  Use either INTEGER or REAL whichever
+** is appropriate.  But only do the conversion if it is possible without
+** loss of information and return the revised type of the argument.
+**
+** This is an EXPERIMENTAL api and is subject to change or removal.
+*/
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value *pVal){
+  Mem *pMem = (Mem*)pVal;
+  applyNumericAffinity(pMem);
+  storeTypeInfo(pMem, 0);
+  return pMem->type;
+}
+
+/*
+** Exported version of applyAffinity(). This one works on sqlite3_value*, 
+** not the internal Mem* type.
+*/
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(
+  sqlite3_value *pVal, 
+  u8 affinity, 
+  u8 enc
+){
+  applyAffinity((Mem *)pVal, affinity, enc);
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Write a nice string representation of the contents of cell pMem
+** into buffer zBuf, length nBuf.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf){
+  char *zCsr = zBuf;
+  int f = pMem->flags;
+
+  static const char *const encnames[] = {"(X)", "(8)", "(16LE)", "(16BE)"};
+
+  if( f&MEM_Blob ){
+    int i;
+    char c;
+    if( f & MEM_Dyn ){
+      c = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      c = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      c = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      c = 's';
+    }
+
+    sqlite3_snprintf(100, zCsr, "%c", c);
+    zCsr += strlen(zCsr);
+    sqlite3_snprintf(100, zCsr, "%d[", pMem->n);
+    zCsr += strlen(zCsr);
+    for(i=0; i<16 && i<pMem->n; i++){
+      sqlite3_snprintf(100, zCsr, "%02X", ((int)pMem->z[i] & 0xFF));
+      zCsr += strlen(zCsr);
+    }
+    for(i=0; i<16 && i<pMem->n; i++){
+      char z = pMem->z[i];
+      if( z<32 || z>126 ) *zCsr++ = '.';
+      else *zCsr++ = z;
+    }
+
+    sqlite3_snprintf(100, zCsr, "]%s", encnames[pMem->enc]);
+    zCsr += strlen(zCsr);
+    if( f & MEM_Zero ){
+      sqlite3_snprintf(100, zCsr,"+%lldz",pMem->u.i);
+      zCsr += strlen(zCsr);
+    }
+    *zCsr = '\0';
+  }else if( f & MEM_Str ){
+    int j, k;
+    zBuf[0] = ' ';
+    if( f & MEM_Dyn ){
+      zBuf[1] = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      zBuf[1] = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      zBuf[1] = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      zBuf[1] = 's';
+    }
+    k = 2;
+    sqlite3_snprintf(100, &zBuf[k], "%d", pMem->n);
+    k += strlen(&zBuf[k]);
+    zBuf[k++] = '[';
+    for(j=0; j<15 && j<pMem->n; j++){
+      u8 c = pMem->z[j];
+      if( c>=0x20 && c<0x7f ){
+        zBuf[k++] = c;
+      }else{
+        zBuf[k++] = '.';
+      }
+    }
+    zBuf[k++] = ']';
+    sqlite3_snprintf(100,&zBuf[k], encnames[pMem->enc]);
+    k += strlen(&zBuf[k]);
+    zBuf[k++] = 0;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the value of a register for tracing purposes:
+*/
+static void memTracePrint(FILE *out, Mem *p){
+  if( p->flags & MEM_Null ){
+    fprintf(out, " NULL");
+  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
+    fprintf(out, " si:%lld", p->u.i);
+  }else if( p->flags & MEM_Int ){
+    fprintf(out, " i:%lld", p->u.i);
+  }else if( p->flags & MEM_Real ){
+    fprintf(out, " r:%g", p->r);
+  }else{
+    char zBuf[200];
+    sqlite3VdbeMemPrettyPrint(p, zBuf);
+    fprintf(out, " ");
+    fprintf(out, "%s", zBuf);
+  }
+}
+static void registerTrace(FILE *out, int iReg, Mem *p){
+  fprintf(out, "REG[%d] = ", iReg);
+  memTracePrint(out, p);
+  fprintf(out, "\n");
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+#  define REGISTER_TRACE(R,M) if(p->trace&&R>0)registerTrace(p->trace,R,M)
+#else
+#  define REGISTER_TRACE(R,M)
+#endif
+
+
+#ifdef VDBE_PROFILE
+/*
+** The following routine only works on pentium-class processors.
+** It uses the RDTSC opcode to read the cycle count value out of the
+** processor and returns that value.  This can be used for high-res
+** profiling.
+*/
+__inline__ unsigned long long int hwtime(void){
+   unsigned int lo, hi;
+   /* We cannot use "=A", since this would use %rax on x86_64 */
+   __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+   return (unsigned long long int)hi << 32 | lo;
+}
+#endif
+
+/*
+** The CHECK_FOR_INTERRUPT macro defined here looks to see if the
+** sqlite3_interrupt() routine has been called.  If it has been, then
+** processing of the VDBE program is interrupted.
+**
+** This macro added to every instruction that does a jump in order to
+** implement a loop.  This test used to be on every single instruction,
+** but that meant we more testing that we needed.  By only testing the
+** flag on jump instructions, we get a (small) speed improvement.
+*/
+#define CHECK_FOR_INTERRUPT \
+   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
+
+
+/*
+** Execute as much of a VDBE program as we can then return.
+**
+** sqlite3VdbeMakeReady() must be called before this routine in order to
+** close the program with a final OP_Halt and to set up the callbacks
+** and the error message pointer.
+**
+** Whenever a row or result data is available, this routine will either
+** invoke the result callback (if there is one) or return with
+** SQLITE_ROW.
+**
+** If an attempt is made to open a locked database, then this routine
+** will either invoke the busy callback (if there is one) or it will
+** return SQLITE_BUSY.
+**
+** If an error occurs, an error message is written to memory obtained
+** from sqlite3_malloc() and p->zErrMsg is made to point to that memory.
+** The error code is stored in p->rc and this routine returns SQLITE_ERROR.
+**
+** If the callback ever returns non-zero, then the program exits
+** immediately.  There will be no error message but the p->rc field is
+** set to SQLITE_ABORT and this routine will return SQLITE_ERROR.
+**
+** A memory allocation error causes p->rc to be set to SQLITE_NOMEM and this
+** routine to return SQLITE_ERROR.
+**
+** Other fatal errors return SQLITE_ERROR.
+**
+** After this routine has finished, sqlite3VdbeFinalize() should be
+** used to clean up the mess that was left behind.
+*/
+SQLITE_PRIVATE int sqlite3VdbeExec(
+  Vdbe *p                    /* The VDBE */
+){
+  int pc;                    /* The program counter */
+  Op *pOp;                   /* Current operation */
+  int rc = SQLITE_OK;        /* Value to return */
+  sqlite3 *db = p->db;       /* The database */
+  u8 encoding = ENC(db);     /* The database encoding */
+  Mem *pIn1, *pIn2, *pIn3;   /* Input operands */
+  Mem *pOut;                 /* Output operand */
+  u8 opProperty;
+#ifdef VDBE_PROFILE
+  unsigned long long start;  /* CPU clock count at start of opcode */
+  int origPc;                /* Program counter at start of opcode */
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
+#endif
+
+  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
+  assert( db->magic==SQLITE_MAGIC_BUSY );
+  sqlite3BtreeMutexArrayEnter(&p->aMutex);
+  if( p->rc==SQLITE_NOMEM ){
+    /* This happens if a malloc() inside a call to sqlite3_column_text() or
+    ** sqlite3_column_text16() failed.  */
+    goto no_mem;
+  }
+  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
+  p->rc = SQLITE_OK;
+  assert( p->explain==0 );
+  p->pResultSet = 0;
+  db->busyHandler.nBusy = 0;
+  CHECK_FOR_INTERRUPT;
+  sqlite3VdbeIOTraceSql(p);
+#ifdef SQLITE_DEBUG
+  sqlite3FaultBeginBenign(-1);
+  if( p->pc==0 && ((p->db->flags & SQLITE_VdbeListing)!=0
+    || sqlite3OsAccess(db->pVfs, "vdbe_explain", SQLITE_ACCESS_EXISTS)==1 )
+  ){
+    int i;
+    printf("VDBE Program Listing:\n");
+    sqlite3VdbePrintSql(p);
+    for(i=0; i<p->nOp; i++){
+      sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+    }
+  }
+  if( sqlite3OsAccess(db->pVfs, "vdbe_trace", SQLITE_ACCESS_EXISTS)==1 ){
+    p->trace = stdout;
+  }
+  sqlite3FaultEndBenign(-1);
+#endif
+  for(pc=p->pc; rc==SQLITE_OK; pc++){
+    assert( pc>=0 && pc<p->nOp );
+    if( db->mallocFailed ) goto no_mem;
+#ifdef VDBE_PROFILE
+    origPc = pc;
+    start = hwtime();
+#endif
+    pOp = &p->aOp[pc];
+
+    /* Only allow tracing if SQLITE_DEBUG is defined.
+    */
+#ifdef SQLITE_DEBUG
+    if( p->trace ){
+      if( pc==0 ){
+        printf("VDBE Execution Trace:\n");
+        sqlite3VdbePrintSql(p);
+      }
+      sqlite3VdbePrintOp(p->trace, pc, pOp);
+    }
+    if( p->trace==0 && pc==0 ){
+      sqlite3FaultBeginBenign(-1);
+      if( sqlite3OsAccess(db->pVfs, "vdbe_sqltrace", SQLITE_ACCESS_EXISTS)==1 ){
+        sqlite3VdbePrintSql(p);
+      }
+      sqlite3FaultEndBenign(-1);
+    }
+#endif
+      
+
+    /* Check to see if we need to simulate an interrupt.  This only happens
+    ** if we have a special test build.
+    */
+#ifdef SQLITE_TEST
+    if( sqlite3_interrupt_count>0 ){
+      sqlite3_interrupt_count--;
+      if( sqlite3_interrupt_count==0 ){
+        sqlite3_interrupt(db);
+      }
+    }
+#endif
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+    /* Call the progress callback if it is configured and the required number
+    ** of VDBE ops have been executed (either since this invocation of
+    ** sqlite3VdbeExec() or since last time the progress callback was called).
+    ** If the progress callback returns non-zero, exit the virtual machine with
+    ** a return code SQLITE_ABORT.
+    */
+    if( db->xProgress ){
+      if( db->nProgressOps==nProgressOps ){
+        int prc;
+        if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+        prc =db->xProgress(db->pProgressArg);
+        if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+        if( prc!=0 ){
+          rc = SQLITE_INTERRUPT;
+          goto vdbe_error_halt;
+        }
+        nProgressOps = 0;
+      }
+      nProgressOps++;
+    }
+#endif
+
+    /* Do common setup processing for any opcode that is marked
+    ** with the "out2-prerelease" tag.  Such opcodes have a single
+    ** output which is specified by the P2 parameter.  The P2 register
+    ** is initialized to a NULL.
+    */
+    opProperty = opcodeProperty[pOp->opcode];
+    if( (opProperty & OPFLG_OUT2_PRERELEASE)!=0 ){
+      assert( pOp->p2>0 );
+      assert( pOp->p2<=p->nMem );
+      pOut = &p->aMem[pOp->p2];
+      sqlite3VdbeMemReleaseExternal(pOut);
+      pOut->flags = MEM_Null;
+    }else
+ 
+    /* Do common setup for opcodes marked with one of the following
+    ** combinations of properties.
+    **
+    **           in1
+    **           in1 in2
+    **           in1 in2 out3
+    **           in1 in3
+    **
+    ** Variables pIn1, pIn2, and pIn3 are made to point to appropriate
+    ** registers for inputs.  Variable pOut points to the output register.
+    */
+    if( (opProperty & OPFLG_IN1)!=0 ){
+      assert( pOp->p1>0 );
+      assert( pOp->p1<=p->nMem );
+      pIn1 = &p->aMem[pOp->p1];
+      REGISTER_TRACE(pOp->p1, pIn1);
+      if( (opProperty & OPFLG_IN2)!=0 ){
+        assert( pOp->p2>0 );
+        assert( pOp->p2<=p->nMem );
+        pIn2 = &p->aMem[pOp->p2];
+        REGISTER_TRACE(pOp->p2, pIn2);
+        if( (opProperty & OPFLG_OUT3)!=0 ){
+          assert( pOp->p3>0 );
+          assert( pOp->p3<=p->nMem );
+          pOut = &p->aMem[pOp->p3];
+        }
+      }else if( (opProperty & OPFLG_IN3)!=0 ){
+        assert( pOp->p3>0 );
+        assert( pOp->p3<=p->nMem );
+        pIn3 = &p->aMem[pOp->p3];
+        REGISTER_TRACE(pOp->p3, pIn3);
+      }
+    }else if( (opProperty & OPFLG_IN2)!=0 ){
+      assert( pOp->p2>0 );
+      assert( pOp->p2<=p->nMem );
+      pIn2 = &p->aMem[pOp->p2];
+      REGISTER_TRACE(pOp->p2, pIn2);
+    }else if( (opProperty & OPFLG_IN3)!=0 ){
+      assert( pOp->p3>0 );
+      assert( pOp->p3<=p->nMem );
+      pIn3 = &p->aMem[pOp->p3];
+      REGISTER_TRACE(pOp->p3, pIn3);
+    }
+
+    switch( pOp->opcode ){
+
+/*****************************************************************************
+** What follows is a massive switch statement where each case implements a
+** separate instruction in the virtual machine.  If we follow the usual
+** indentation conventions, each case should be indented by 6 spaces.  But
+** that is a lot of wasted space on the left margin.  So the code within
+** the switch statement will break with convention and be flush-left. Another
+** big comment (similar to this one) will mark the point in the code where
+** we transition back to normal indentation.
+**
+** The formatting of each case is important.  The makefile for SQLite
+** generates two C files "opcodes.h" and "opcodes.c" by scanning this
+** file looking for lines that begin with "case OP_".  The opcodes.h files
+** will be filled with #defines that give unique integer values to each
+** opcode and the opcodes.c file is filled with an array of strings where
+** each string is the symbolic name for the corresponding opcode.  If the
+** case statement is followed by a comment of the form "/# same as ... #/"
+** that comment is used to determine the particular value of the opcode.
+**
+** Other keywords in the comment that follows each case are used to
+** construct the OPFLG_INITIALIZER value that initializes opcodeProperty[].
+** Keywords include: in1, in2, in3, out2_prerelease, out2, out3.  See
+** the mkopcodeh.awk script for additional information.
+**
+** Documentation about VDBE opcodes is generated by scanning this file
+** for lines of that contain "Opcode:".  That line and all subsequent
+** comment lines are used in the generation of the opcode.html documentation
+** file.
+**
+** SUMMARY:
+**
+**     Formatting is important to scripts that scan this file.
+**     Do not deviate from the formatting style currently in use.
+**
+*****************************************************************************/
+
+/* Opcode:  Goto * P2 * * *
+**
+** An unconditional jump to address P2.
+** The next instruction executed will be 
+** the one at index P2 from the beginning of
+** the program.
+*/
+case OP_Goto: {             /* jump */
+  CHECK_FOR_INTERRUPT;
+  pc = pOp->p2 - 1;
+  break;
+}
+
+/* Opcode:  Gosub * P2 * * *
+**
+** Push the current address plus 1 onto the return address stack
+** and then jump to address P2.
+**
+** The return address stack is of limited depth.  If too many
+** OP_Gosub operations occur without intervening OP_Returns, then
+** the return address stack will fill up and processing will abort
+** with a fatal error.
+*/
+case OP_Gosub: {            /* jump */
+  assert( p->returnDepth<sizeof(p->returnStack)/sizeof(p->returnStack[0]) );
+  p->returnStack[p->returnDepth++] = pc+1;
+  pc = pOp->p2 - 1;
+  break;
+}
+
+/* Opcode:  Return * * * * *
+**
+** Jump immediately to the next instruction after the last unreturned
+** OP_Gosub.  If an OP_Return has occurred for all OP_Gosubs, then
+** processing aborts with a fatal error.
+*/
+case OP_Return: {
+  assert( p->returnDepth>0 );
+  p->returnDepth--;
+  pc = p->returnStack[p->returnDepth] - 1;
+  break;
+}
+
+/* Opcode:  Halt P1 P2 * P4 *
+**
+** Exit immediately.  All open cursors, Fifos, etc are closed
+** automatically.
+**
+** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
+** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
+** For errors, it can be some other value.  If P1!=0 then P2 will determine
+** whether or not to rollback the current transaction.  Do not rollback
+** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
+** then back out all changes that have occurred during this execution of the
+** VDBE, but do not rollback the transaction. 
+**
+** If P4 is not null then it is an error message string.
+**
+** There is an implied "Halt 0 0 0" instruction inserted at the very end of
+** every program.  So a jump past the last instruction of the program
+** is the same as executing Halt.
+*/
+case OP_Halt: {
+  p->rc = pOp->p1;
+  p->pc = pc;
+  p->errorAction = pOp->p2;
+  if( pOp->p4.z ){
+    sqlite3SetString(&p->zErrMsg, pOp->p4.z, (char*)0);
+  }
+  rc = sqlite3VdbeHalt(p);
+  assert( rc==SQLITE_BUSY || rc==SQLITE_OK );
+  if( rc==SQLITE_BUSY ){
+    p->rc = rc = SQLITE_BUSY;
+  }else{
+    rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
+  }
+  goto vdbe_return;
+}
+
+/* Opcode: Integer P1 P2 * * *
+**
+** The 32-bit integer value P1 is written into register P2.
+*/
+case OP_Integer: {         /* out2-prerelease */
+  pOut->flags = MEM_Int;
+  pOut->u.i = pOp->p1;
+  break;
+}
+
+/* Opcode: Int64 * P2 * P4 *
+**
+** P4 is a pointer to a 64-bit integer value.
+** Write that value into register P2.
+*/
+case OP_Int64: {           /* out2-prerelease */
+  assert( pOp->p4.pI64!=0 );
+  pOut->flags = MEM_Int;
+  pOut->u.i = *pOp->p4.pI64;
+  break;
+}
+
+/* Opcode: Real * P2 * P4 *
+**
+** P4 is a pointer to a 64-bit floating point value.
+** Write that value into register P2.
+*/
+case OP_Real: {            /* same as TK_FLOAT, out2-prerelease */
+  pOut->flags = MEM_Real;
+  assert( !sqlite3IsNaN(*pOp->p4.pReal) );
+  pOut->r = *pOp->p4.pReal;
+  break;
+}
+
+/* Opcode: String8 * P2 * P4 *
+**
+** P4 points to a nul terminated UTF-8 string. This opcode is transformed 
+** into an OP_String before it is executed for the first time.
+*/
+case OP_String8: {         /* same as TK_STRING, out2-prerelease */
+  assert( pOp->p4.z!=0 );
+  pOp->opcode = OP_String;
+  pOp->p1 = strlen(pOp->p4.z);
+
+#ifndef SQLITE_OMIT_UTF16
+  if( encoding!=SQLITE_UTF8 ){
+    sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
+    if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pOut, encoding) ) goto no_mem;
+    if( SQLITE_OK!=sqlite3VdbeMemDynamicify(pOut) ) goto no_mem;
+    pOut->zMalloc = 0;
+    pOut->flags |= MEM_Static;
+    pOut->flags &= ~MEM_Dyn;
+    if( pOp->p4type==P4_DYNAMIC ){
+      sqlite3_free(pOp->p4.z);
+    }
+    pOp->p4type = P4_DYNAMIC;
+    pOp->p4.z = pOut->z;
+    pOp->p1 = pOut->n;
+    if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+    UPDATE_MAX_BLOBSIZE(pOut);
+    break;
+  }
+#endif
+  if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  /* Fall through to the next case, OP_String */
+}
+  
+/* Opcode: String P1 P2 * P4 *
+**
+** The string value P4 of length P1 (bytes) is stored in register P2.
+*/
+case OP_String: {          /* out2-prerelease */
+  assert( pOp->p4.z!=0 );
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = pOp->p4.z;
+  pOut->n = pOp->p1;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Null * P2 * * *
+**
+** Write a NULL into register P2.
+*/
+case OP_Null: {           /* out2-prerelease */
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+/* Opcode: Blob P1 P2 * P4
+**
+** P4 points to a blob of data P1 bytes long.  Store this
+** blob in register P2. This instruction is not coded directly
+** by the compiler. Instead, the compiler layer specifies
+** an OP_HexBlob opcode, with the hex string representation of
+** the blob as P4. This opcode is transformed to an OP_Blob
+** the first time it is executed.
+*/
+case OP_Blob: {                /* out2-prerelease */
+  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
+  sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+#endif /* SQLITE_OMIT_BLOB_LITERAL */
+
+/* Opcode: Variable P1 P2 * * *
+**
+** The value of variable P1 is written into register P2. A variable is
+** an unknown in the original SQL string as handed to sqlite3_compile().
+** Any occurance of the '?' character in the original SQL is considered
+** a variable.  Variables in the SQL string are number from left to
+** right beginning with 1.  The values of variables are set using the
+** sqlite3_bind() API.
+*/
+case OP_Variable: {           /* out2-prerelease */
+  int j = pOp->p1 - 1;
+  Mem *pVar;
+  assert( j>=0 && j<p->nVar );
+
+  pVar = &p->aVar[j];
+  if( sqlite3VdbeMemTooBig(pVar) ){
+    goto too_big;
+  }
+  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Move P1 P2 * * *
+**
+** Move the value in register P1 over into register P2.  Register P1
+** is left holding a NULL.  It is an error for P1 and P2 to be the
+** same register.
+*/
+case OP_Move: {
+  char *zMalloc;
+  assert( pOp->p1>0 );
+  assert( pOp->p1<=p->nMem );
+  pIn1 = &p->aMem[pOp->p1];
+  REGISTER_TRACE(pOp->p1, pIn1);
+  assert( pOp->p2>0 );
+  assert( pOp->p2<=p->nMem );
+  pOut = &p->aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  zMalloc = pOut->zMalloc;
+  pOut->zMalloc = 0;
+  sqlite3VdbeMemMove(pOut, pIn1);
+  pIn1->zMalloc = zMalloc;
+  REGISTER_TRACE(pOp->p2, pOut);
+  break;
+}
+
+/* Opcode: Copy P1 P2 * * *
+**
+** Make a copy of register P1 into register P2.
+**
+** This instruction makes a deep copy of the value.  A duplicate
+** is made of any string or blob constant.  See also OP_SCopy.
+*/
+case OP_Copy: {
+  assert( pOp->p1>0 );
+  assert( pOp->p1<=p->nMem );
+  pIn1 = &p->aMem[pOp->p1];
+  REGISTER_TRACE(pOp->p1, pIn1);
+  assert( pOp->p2>0 );
+  assert( pOp->p2<=p->nMem );
+  pOut = &p->aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+  Deephemeralize(pOut);
+  REGISTER_TRACE(pOp->p2, pOut);
+  break;
+}
+
+/* Opcode: SCopy P1 P2 * * *
+**
+** Make a shallow copy of register P1 into register P2.
+**
+** This instruction makes a shallow copy of the value.  If the value
+** is a string or blob, then the copy is only a pointer to the
+** original and hence if the original changes so will the copy.
+** Worse, if the original is deallocated, the copy becomes invalid.
+** Thus the program must guarantee that the original will not change
+** during the lifetime of the copy.  Use OP_Copy to make a complete
+** copy.
+*/
+case OP_SCopy: {
+  assert( pOp->p1>0 );
+  assert( pOp->p1<=p->nMem );
+  pIn1 = &p->aMem[pOp->p1];
+  REGISTER_TRACE(pOp->p1, pIn1);
+  assert( pOp->p2>0 );
+  assert( pOp->p2<=p->nMem );
+  pOut = &p->aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+  REGISTER_TRACE(pOp->p2, pOut);
+  break;
+}
+
+/* Opcode: ResultRow P1 P2 * * *
+**
+** The registers P1 throught P1+P2-1 contain a single row of
+** results. This opcode causes the sqlite3_step() call to terminate
+** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
+** structure to provide access to the top P1 values as the result
+** row.
+*/
+case OP_ResultRow: {
+  Mem *pMem;
+  int i;
+  assert( p->nResColumn==pOp->p2 );
+  assert( pOp->p1>0 );
+  assert( pOp->p1+pOp->p2<=p->nMem );
+
+  /* Invalidate all ephemeral cursor row caches */
+  p->cacheCtr = (p->cacheCtr + 2)|1;
+
+  /* Make sure the results of the current row are \000 terminated
+  ** and have an assigned type.  The results are deephemeralized as
+  ** as side effect.
+  */
+  pMem = p->pResultSet = &p->aMem[pOp->p1];
+  for(i=0; i<pOp->p2; i++){
+    sqlite3VdbeMemNulTerminate(&pMem[i]);
+    storeTypeInfo(&pMem[i], encoding);
+  }
+  if( db->mallocFailed ) goto no_mem;
+
+  /* Return SQLITE_ROW
+  */
+  p->nCallback++;
+  p->pc = pc + 1;
+  rc = SQLITE_ROW;
+  goto vdbe_return;
+}
+
+/* Opcode: Concat P1 P2 P3 * *
+**
+** Add the text in register P1 onto the end of the text in
+** register P2 and store the result in register P3.
+** If either the P1 or P2 text are NULL then store NULL in P3.
+**
+**   P3 = P2 || P1
+**
+** It is illegal for P1 and P3 to be the same register. Sometimes,
+** if P3 is the same register as P2, the implementation is able
+** to avoid a memcpy().
+*/
+case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
+  i64 nByte;
+
+  assert( pIn1!=pOut );
+  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  ExpandBlob(pIn1);
+  Stringify(pIn1, encoding);
+  ExpandBlob(pIn2);
+  Stringify(pIn2, encoding);
+  nByte = pIn1->n + pIn2->n;
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  MemSetTypeFlag(pOut, MEM_Str);
+  if( sqlite3VdbeMemGrow(pOut, nByte+2, pOut==pIn2) ){
+    goto no_mem;
+  }
+  if( pOut!=pIn2 ){
+    memcpy(pOut->z, pIn2->z, pIn2->n);
+  }
+  memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
+  pOut->z[nByte] = 0;
+  pOut->z[nByte+1] = 0;
+  pOut->flags |= MEM_Term;
+  pOut->n = nByte;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Add P1 P2 P3 * *
+**
+** Add the value in register P1 to the value in register P2
+** and store the result in regiser P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Multiply P1 P2 P3 * *
+**
+**
+** Multiply the value in regiser P1 by the value in regiser P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Subtract P1 P2 P3 * *
+**
+** Subtract the value in register P1 from the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Divide P1 P2 P3 * *
+**
+** Divide the value in register P1 by the value in register P2
+** and store the result in register P3.  If the value in register P2
+** is zero, then the result is NULL.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Remainder P1 P2 P3 * *
+**
+** Compute the remainder after integer division of the value in
+** register P1 by the value in register P2 and store the result in P3. 
+** If the value in register P2 is zero the result is NULL.
+** If either operand is NULL, the result is NULL.
+*/
+case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
+case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
+case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
+case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
+case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
+  int flags;
+  flags = pIn1->flags | pIn2->flags;
+  if( (flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
+  if( (pIn1->flags & pIn2->flags & MEM_Int)==MEM_Int ){
+    i64 a, b;
+    a = pIn1->u.i;
+    b = pIn2->u.i;
+    switch( pOp->opcode ){
+      case OP_Add:         b += a;       break;
+      case OP_Subtract:    b -= a;       break;
+      case OP_Multiply:    b *= a;       break;
+      case OP_Divide: {
+        if( a==0 ) goto arithmetic_result_is_null;
+        /* Dividing the largest possible negative 64-bit integer (1<<63) by 
+        ** -1 returns an integer too large to store in a 64-bit data-type. On
+        ** some architectures, the value overflows to (1<<63). On others,
+        ** a SIGFPE is issued. The following statement normalizes this
+        ** behaviour so that all architectures behave as if integer 
+        ** overflow occured.
+        */
+        if( a==-1 && b==SMALLEST_INT64 ) a = 1;
+        b /= a;
+        break;
+      }
+      default: {
+        if( a==0 ) goto arithmetic_result_is_null;
+        if( a==-1 ) a = 1;
+        b %= a;
+        break;
+      }
+    }
+    pOut->u.i = b;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }else{
+    double a, b;
+    a = sqlite3VdbeRealValue(pIn1);
+    b = sqlite3VdbeRealValue(pIn2);
+    switch( pOp->opcode ){
+      case OP_Add:         b += a;       break;
+      case OP_Subtract:    b -= a;       break;
+      case OP_Multiply:    b *= a;       break;
+      case OP_Divide: {
+        if( a==0.0 ) goto arithmetic_result_is_null;
+        b /= a;
+        break;
+      }
+      default: {
+        i64 ia = (i64)a;
+        i64 ib = (i64)b;
+        if( ia==0 ) goto arithmetic_result_is_null;
+        if( ia==-1 ) ia = 1;
+        b = ib % ia;
+        break;
+      }
+    }
+    if( sqlite3IsNaN(b) ){
+      goto arithmetic_result_is_null;
+    }
+    pOut->r = b;
+    MemSetTypeFlag(pOut, MEM_Real);
+    if( (flags & MEM_Real)==0 ){
+      sqlite3VdbeIntegerAffinity(pOut);
+    }
+  }
+  break;
+
+arithmetic_result_is_null:
+  sqlite3VdbeMemSetNull(pOut);
+  break;
+}
+
+/* Opcode: CollSeq * * P4
+**
+** P4 is a pointer to a CollSeq struct. If the next call to a user function
+** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
+** be returned. This is used by the built-in min(), max() and nullif()
+** functions.
+**
+** The interface used by the implementation of the aforementioned functions
+** to retrieve the collation sequence set by this opcode is not available
+** publicly, only to user functions defined in func.c.
+*/
+case OP_CollSeq: {
+  assert( pOp->p4type==P4_COLLSEQ );
+  break;
+}
+
+/* Opcode: Function P1 P2 P3 P4 P5
+**
+** Invoke a user function (P4 is a pointer to a Function structure that
+** defines the function) with P5 arguments taken from register P2 and
+** successors.  The result of the function is stored in register P3.
+** Register P3 must not be one of the function inputs.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the 
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** See also: AggStep and AggFinal
+*/
+case OP_Function: {
+  int i;
+  Mem *pArg;
+  sqlite3_context ctx;
+  sqlite3_value **apVal;
+  int n = pOp->p5;
+
+  apVal = p->apArg;
+  assert( apVal || n==0 );
+
+  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=p->nMem) );
+  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
+  pArg = &p->aMem[pOp->p2];
+  for(i=0; i<n; i++, pArg++){
+    apVal[i] = pArg;
+    storeTypeInfo(pArg, encoding);
+    REGISTER_TRACE(pOp->p2, pArg);
+  }
+
+  assert( pOp->p4type==P4_FUNCDEF || pOp->p4type==P4_VDBEFUNC );
+  if( pOp->p4type==P4_FUNCDEF ){
+    ctx.pFunc = pOp->p4.pFunc;
+    ctx.pVdbeFunc = 0;
+  }else{
+    ctx.pVdbeFunc = (VdbeFunc*)pOp->p4.pVdbeFunc;
+    ctx.pFunc = ctx.pVdbeFunc->pFunc;
+  }
+
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pOut = &p->aMem[pOp->p3];
+  ctx.s.flags = MEM_Null;
+  ctx.s.db = db;
+  ctx.s.xDel = 0;
+  ctx.s.zMalloc = 0;
+
+  /* The output cell may already have a buffer allocated. Move
+  ** the pointer to ctx.s so in case the user-function can use
+  ** the already allocated buffer instead of allocating a new one.
+  */
+  sqlite3VdbeMemMove(&ctx.s, pOut);
+  MemSetTypeFlag(&ctx.s, MEM_Null);
+
+  ctx.isError = 0;
+  if( ctx.pFunc->needCollSeq ){
+    assert( pOp>p->aOp );
+    assert( pOp[-1].p4type==P4_COLLSEQ );
+    assert( pOp[-1].opcode==OP_CollSeq );
+    ctx.pColl = pOp[-1].p4.pColl;
+  }
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
+  if( sqlite3SafetyOn(db) ){
+    sqlite3VdbeMemRelease(&ctx.s);
+    goto abort_due_to_misuse;
+  }
+  if( db->mallocFailed ){
+    /* Even though a malloc() has failed, the implementation of the
+    ** user function may have called an sqlite3_result_XXX() function
+    ** to return a value. The following call releases any resources
+    ** associated with such a value.
+    **
+    ** Note: Maybe MemRelease() should be called if sqlite3SafetyOn()
+    ** fails also (the if(...) statement above). But if people are
+    ** misusing sqlite, they have bigger problems than a leaked value.
+    */
+    sqlite3VdbeMemRelease(&ctx.s);
+    goto no_mem;
+  }
+
+  /* If any auxilary data functions have been called by this user function,
+  ** immediately call the destructor for any non-static values.
+  */
+  if( ctx.pVdbeFunc ){
+    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
+    pOp->p4.pVdbeFunc = ctx.pVdbeFunc;
+    pOp->p4type = P4_VDBEFUNC;
+  }
+
+  /* If the function returned an error, throw an exception */
+  if( ctx.isError ){
+    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
+    rc = ctx.isError;
+  }
+
+  /* Copy the result of the function into register P3 */
+  sqlite3VdbeChangeEncoding(&ctx.s, encoding);
+  sqlite3VdbeMemMove(pOut, &ctx.s);
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    goto too_big;
+  }
+  REGISTER_TRACE(pOp->p3, pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: BitAnd P1 P2 P3 * *
+**
+** Take the bit-wise AND of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: BitOr P1 P2 P3 * *
+**
+** Take the bit-wise OR of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftLeft P1 P2 P3 * *
+**
+** Shift the integer value in register P2 to the left by the
+** number of bits specified by the integer in regiser P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftRight P1 P2 P3 * *
+**
+** Shift the integer value in register P2 to the right by the
+** number of bits specified by the integer in register P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
+case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
+case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
+case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
+  i64 a, b;
+
+  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  a = sqlite3VdbeIntValue(pIn2);
+  b = sqlite3VdbeIntValue(pIn1);
+  switch( pOp->opcode ){
+    case OP_BitAnd:      a &= b;     break;
+    case OP_BitOr:       a |= b;     break;
+    case OP_ShiftLeft:   a <<= b;    break;
+    default:  assert( pOp->opcode==OP_ShiftRight );
+                         a >>= b;    break;
+  }
+  pOut->u.i = a;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+/* Opcode: AddImm  P1 P2 * * *
+** 
+** Add the constant P2 the value in register P1.
+** The result is always an integer.
+**
+** To force any register to be an integer, just add 0.
+*/
+case OP_AddImm: {            /* in1 */
+  sqlite3VdbeMemIntegerify(pIn1);
+  pIn1->u.i += pOp->p2;
+  break;
+}
+
+/* Opcode: ForceInt P1 P2 P3 * *
+**
+** Convert value in register P1 into an integer.  If the value 
+** in P1 is not numeric (meaning that is is a NULL or a string that
+** does not look like an integer or floating point number) then
+** jump to P2.  If the value in P1 is numeric then
+** convert it into the least integer that is greater than or equal to its
+** current value if P3==0, or to the least integer that is strictly
+** greater than its current value if P3==1.
+*/
+case OP_ForceInt: {            /* jump, in1 */
+  i64 v;
+  applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
+  if( (pIn1->flags & (MEM_Int|MEM_Real))==0 ){
+    pc = pOp->p2 - 1;
+    break;
+  }
+  if( pIn1->flags & MEM_Int ){
+    v = pIn1->u.i + (pOp->p3!=0);
+  }else{
+    assert( pIn1->flags & MEM_Real );
+    v = (sqlite3_int64)pIn1->r;
+    if( pIn1->r>(double)v ) v++;
+    if( pOp->p3 && pIn1->r==(double)v ) v++;
+  }
+  pIn1->u.i = v;
+  MemSetTypeFlag(pIn1, MEM_Int);
+  break;
+}
+
+/* Opcode: MustBeInt P1 P2 * * *
+** 
+** Force the value in register P1 to be an integer.  If the value
+** in P1 is not an integer and cannot be converted into an integer
+** without data loss, then jump immediately to P2, or if P2==0
+** raise an SQLITE_MISMATCH exception.
+*/
+case OP_MustBeInt: {            /* jump, in1 */
+  applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
+  if( (pIn1->flags & MEM_Int)==0 ){
+    if( pOp->p2==0 ){
+      rc = SQLITE_MISMATCH;
+      goto abort_due_to_error;
+    }else{
+      pc = pOp->p2 - 1;
+    }
+  }else{
+    MemSetTypeFlag(pIn1, MEM_Int);
+  }
+  break;
+}
+
+/* Opcode: RealAffinity P1 * * * *
+**
+** If register P1 holds an integer convert it to a real value.
+**
+** This opcode is used when extracting information from a column that
+** has REAL affinity.  Such column values may still be stored as
+** integers, for space efficiency, but after extraction we want them
+** to have only a real value.
+*/
+case OP_RealAffinity: {                  /* in1 */
+  if( pIn1->flags & MEM_Int ){
+    sqlite3VdbeMemRealify(pIn1);
+  }
+  break;
+}
+
+#ifndef SQLITE_OMIT_CAST
+/* Opcode: ToText P1 * * * *
+**
+** Force the value in register P1 to be text.
+** If the value is numeric, convert it to a string using the
+** equivalent of printf().  Blob values are unchanged and
+** are afterwards simply interpreted as text.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
+  if( pIn1->flags & MEM_Null ) break;
+  assert( MEM_Str==(MEM_Blob>>3) );
+  pIn1->flags |= (pIn1->flags&MEM_Blob)>>3;
+  applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
+  rc = ExpandBlob(pIn1);
+  assert( pIn1->flags & MEM_Str || db->mallocFailed );
+  pIn1->flags &= ~(MEM_Int|MEM_Real|MEM_Blob);
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  break;
+}
+
+/* Opcode: ToBlob P1 * * * *
+**
+** Force the value in register P1 to be a BLOB.
+** If the value is numeric, convert it to a string first.
+** Strings are simply reinterpreted as blobs with no change
+** to the underlying data.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToBlob: {                  /* same as TK_TO_BLOB, in1 */
+  if( pIn1->flags & MEM_Null ) break;
+  if( (pIn1->flags & MEM_Blob)==0 ){
+    applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
+    assert( pIn1->flags & MEM_Str || db->mallocFailed );
+  }
+  MemSetTypeFlag(pIn1, MEM_Blob);
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  break;
+}
+
+/* Opcode: ToNumeric P1 * * * *
+**
+** Force the value in register P1 to be numeric (either an
+** integer or a floating-point number.)
+** If the value is text or blob, try to convert it to an using the
+** equivalent of atoi() or atof() and store 0 if no such conversion 
+** is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, in1 */
+  if( (pIn1->flags & (MEM_Null|MEM_Int|MEM_Real))==0 ){
+    sqlite3VdbeMemNumerify(pIn1);
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_CAST */
+
+/* Opcode: ToInt P1 * * * *
+**
+** Force the value in register P1 be an integer.  If
+** The value is currently a real number, drop its fractional part.
+** If the value is text or blob, try to convert it to an integer using the
+** equivalent of atoi() and store 0 if no such conversion is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToInt: {                  /* same as TK_TO_INT, in1 */
+  if( (pIn1->flags & MEM_Null)==0 ){
+    sqlite3VdbeMemIntegerify(pIn1);
+  }
+  break;
+}
+
+#ifndef SQLITE_OMIT_CAST
+/* Opcode: ToReal P1 * * * *
+**
+** Force the value in register P1 to be a floating point number.
+** If The value is currently an integer, convert it.
+** If the value is text or blob, try to convert it to an integer using the
+** equivalent of atoi() and store 0.0 if no such conversion is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
+  if( (pIn1->flags & MEM_Null)==0 ){
+    sqlite3VdbeMemRealify(pIn1);
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_CAST */
+
+/* Opcode: Lt P1 P2 P3 P4 P5
+**
+** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
+** jump to address P2.  
+**
+** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
+** reg(P3) is NULL then take the jump.  If the SQLITE_JUMPIFNULL 
+** bit is clear then fall thru if either operand is NULL.
+**
+** If the SQLITE_NULLEQUAL bit of P5 is set then treat NULL operands
+** as being equal to one another.  Normally NULLs are not equal to 
+** anything including other NULLs.
+**
+** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made 
+** to coerce both inputs according to this affinity before the
+** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
+** affinity is used. Note that the affinity conversions are stored
+** back into the input registers P1 and P3.  So this opcode can cause
+** persistent changes to registers P1 and P3.
+**
+** Once any conversions have taken place, and neither value is NULL, 
+** the values are compared. If both values are blobs then memcmp() is
+** used to determine the results of the comparison.  If both values
+** are text, then the appropriate collating function specified in
+** P4 is  used to do the comparison.  If P4 is not specified then
+** memcmp() is used to compare text string.  If both values are
+** numeric, then a numeric comparison is used. If the two values
+** are of different types, then numbers are considered less than
+** strings and strings are considered less than blobs.
+**
+** If the SQLITE_STOREP2 bit of P5 is set, then do not jump.  Instead,
+** store a boolean result (either 0, or 1, or NULL) in register P2.
+*/
+/* Opcode: Ne P1 P2 P3 P4 P5
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
+** additional information.
+*/
+/* Opcode: Eq P1 P2 P3 P4 P5
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the operands in registers P1 and P3 are equal.
+** See the Lt opcode for additional information.
+*/
+/* Opcode: Le P1 P2 P3 P4 P5
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is less than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Gt P1 P2 P3 P4 P5
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Ge P1 P2 P3 P4 P5
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
+case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
+case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
+case OP_Le:               /* same as TK_LE, jump, in1, in3 */
+case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
+case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
+  int flags;
+  int res;
+  char affinity;
+  Mem x1, x3;
+
+  flags = pIn1->flags|pIn3->flags;
+
+  if( flags&MEM_Null ){
+    if( (pOp->p5 & SQLITE_NULLEQUAL)!=0 ){
+      /*
+      ** When SQLITE_NULLEQUAL set and either operand is NULL
+      ** then both operands are converted to integers prior to being 
+      ** passed down into the normal comparison logic below.  
+      ** NULL operands are converted to zero and non-NULL operands
+      ** are converted to 1.  Thus, for example, with SQLITE_NULLEQUAL
+      ** set,  NULL==NULL is true whereas it would normally NULL.
+      ** Similarly,  NULL!=123 is true.
+      */
+      x1.flags = MEM_Int;
+      x1.u.i = (pIn1->flags & MEM_Null)==0;
+      pIn1 = &x1;
+      x3.flags = MEM_Int;
+      x3.u.i = (pIn3->flags & MEM_Null)==0;
+      pIn3 = &x3;
+    }else{
+      /* If the SQLITE_NULLEQUAL bit is clear and either operand is NULL then
+      ** the result is always NULL.  The jump is taken if the 
+      ** SQLITE_JUMPIFNULL bit is set.
+      */
+      if( pOp->p5 & SQLITE_STOREP2 ){
+        pOut = &p->aMem[pOp->p2];
+        MemSetTypeFlag(pOut, MEM_Null);
+        REGISTER_TRACE(pOp->p2, pOut);
+      }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
+        pc = pOp->p2-1;
+      }
+      break;
+    }
+  }
+
+  affinity = pOp->p5 & SQLITE_AFF_MASK;
+  if( affinity ){
+    applyAffinity(pIn1, affinity, encoding);
+    applyAffinity(pIn3, affinity, encoding);
+  }
+
+  assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
+  ExpandBlob(pIn1);
+  ExpandBlob(pIn3);
+  res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
+  switch( pOp->opcode ){
+    case OP_Eq:    res = res==0;     break;
+    case OP_Ne:    res = res!=0;     break;
+    case OP_Lt:    res = res<0;      break;
+    case OP_Le:    res = res<=0;     break;
+    case OP_Gt:    res = res>0;      break;
+    default:       res = res>=0;     break;
+  }
+
+  if( pOp->p5 & SQLITE_STOREP2 ){
+    pOut = &p->aMem[pOp->p2];
+    MemSetTypeFlag(pOut, MEM_Int);
+    pOut->u.i = res;
+    REGISTER_TRACE(pOp->p2, pOut);
+  }else if( res ){
+    pc = pOp->p2-1;
+  }
+  break;
+}
+
+/* Opcode: And P1 P2 P3 * *
+**
+** Take the logical AND of the values in registers P1 and P2 and
+** write the result into register P3.
+**
+** If either P1 or P2 is 0 (false) then the result is 0 even if
+** the other input is NULL.  A NULL and true or two NULLs give
+** a NULL output.
+*/
+/* Opcode: Or P1 P2 P3 * *
+**
+** Take the logical OR of the values in register P1 and P2 and
+** store the answer in register P3.
+**
+** If either P1 or P2 is nonzero (true) then the result is 1 (true)
+** even if the other input is NULL.  A NULL and false or two NULLs
+** give a NULL output.
+*/
+case OP_And:              /* same as TK_AND, in1, in2, out3 */
+case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
+  int v1, v2;    /* 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+
+  if( pIn1->flags & MEM_Null ){
+    v1 = 2;
+  }else{
+    v1 = sqlite3VdbeIntValue(pIn1)!=0;
+  }
+  if( pIn2->flags & MEM_Null ){
+    v2 = 2;
+  }else{
+    v2 = sqlite3VdbeIntValue(pIn2)!=0;
+  }
+  if( pOp->opcode==OP_And ){
+    static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
+    v1 = and_logic[v1*3+v2];
+  }else{
+    static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
+    v1 = or_logic[v1*3+v2];
+  }
+  if( v1==2 ){
+    MemSetTypeFlag(pOut, MEM_Null);
+  }else{
+    pOut->u.i = v1;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }
+  break;
+}
+
+/* Opcode: Not P1 * * * *
+**
+** Interpret the value in register P1 as a boolean value.  Replace it
+** with its complement.  If the value in register P1 is NULL its value
+** is unchanged.
+*/
+case OP_Not: {                /* same as TK_NOT, in1 */
+  if( pIn1->flags & MEM_Null ) break;  /* Do nothing to NULLs */
+  sqlite3VdbeMemIntegerify(pIn1);
+  pIn1->u.i = !pIn1->u.i;
+  assert( pIn1->flags&MEM_Int );
+  break;
+}
+
+/* Opcode: BitNot P1 * * * *
+**
+** Interpret the content of register P1 as an integer.  Replace it
+** with its ones-complement.  If the value is originally NULL, leave
+** it unchanged.
+*/
+case OP_BitNot: {             /* same as TK_BITNOT, in1 */
+  if( pIn1->flags & MEM_Null ) break;  /* Do nothing to NULLs */
+  sqlite3VdbeMemIntegerify(pIn1);
+  pIn1->u.i = ~pIn1->u.i;
+  assert( pIn1->flags&MEM_Int );
+  break;
+}
+
+/* Opcode: If P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is true.  The value is
+** is considered true if it is numeric and non-zero.  If the value
+** in P1 is NULL then take the jump if P3 is true.
+*/
+/* Opcode: IfNot P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is False.  The value is
+** is considered true if it has a numeric value of zero.  If the value
+** in P1 is NULL then take the jump if P3 is true.
+*/
+case OP_If:                 /* jump, in1 */
+case OP_IfNot: {            /* jump, in1 */
+  int c;
+  if( pIn1->flags & MEM_Null ){
+    c = pOp->p3;
+  }else{
+#ifdef SQLITE_OMIT_FLOATING_POINT
+    c = sqlite3VdbeIntValue(pIn1);
+#else
+    c = sqlite3VdbeRealValue(pIn1)!=0.0;
+#endif
+    if( pOp->opcode==OP_IfNot ) c = !c;
+  }
+  if( c ){
+    pc = pOp->p2-1;
+  }
+  break;
+}
+
+/* Opcode: IsNull P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is NULL.  If P3 is greater
+** than zero, then check all values reg(P1), reg(P1+1), 
+** reg(P1+2), ..., reg(P1+P3-1).
+*/
+case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
+  int n = pOp->p3;
+  assert( pOp->p3==0 || pOp->p1>0 );
+  do{
+    if( (pIn1->flags & MEM_Null)!=0 ){
+      pc = pOp->p2 - 1;
+      break;
+    }
+    pIn1++;
+  }while( --n > 0 );
+  break;
+}
+
+/* Opcode: NotNull P1 P2 * * *
+**
+** Jump to P2 if the value in register P1 is not NULL.  
+*/
+case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
+  if( (pIn1->flags & MEM_Null)==0 ){
+    pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: SetNumColumns * P2 * * *
+**
+** This opcode sets the number of columns for the cursor opened by the
+** following instruction to P2.
+**
+** An OP_SetNumColumns is only useful if it occurs immediately before 
+** one of the following opcodes:
+**
+**     OpenRead
+**     OpenWrite
+**     OpenPseudo
+**
+** If the OP_Column opcode is to be executed on a cursor, then
+** this opcode must be present immediately before the opcode that
+** opens the cursor.
+*/
+case OP_SetNumColumns: {
+  break;
+}
+
+/* Opcode: Column P1 P2 P3 P4 *
+**
+** Interpret the data that cursor P1 points to as a structure built using
+** the MakeRecord instruction.  (See the MakeRecord opcode for additional
+** information about the format of the data.)  Extract the P2-th column
+** from this record.  If there are less that (P2+1) 
+** values in the record, extract a NULL.
+**
+** The value extracted is stored in register P3.
+**
+** If the KeyAsData opcode has previously executed on this cursor, then the
+** field might be extracted from the key rather than the data.
+**
+** If the column contains fewer than P2 fields, then extract a NULL.  Or,
+** if the P4 argument is a P4_MEM use the value of the P4 argument as
+** the result.
+*/
+case OP_Column: {
+  u32 payloadSize;   /* Number of bytes in the record */
+  int p1 = pOp->p1;  /* P1 value of the opcode */
+  int p2 = pOp->p2;  /* column number to retrieve */
+  Cursor *pC = 0;    /* The VDBE cursor */
+  char *zRec;        /* Pointer to complete record-data */
+  BtCursor *pCrsr;   /* The BTree cursor */
+  u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
+  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
+  u32 nField;        /* number of fields in the record */
+  int len;           /* The length of the serialized data for the column */
+  int i;             /* Loop counter */
+  char *zData;       /* Part of the record being decoded */
+  Mem *pDest;        /* Where to write the extracted value */
+  Mem sMem;          /* For storing the record being decoded */
+
+  sMem.flags = 0;
+  sMem.db = 0;
+  sMem.zMalloc = 0;
+  assert( p1<p->nCursor );
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pDest = &p->aMem[pOp->p3];
+  MemSetTypeFlag(pDest, MEM_Null);
+
+  /* This block sets the variable payloadSize to be the total number of
+  ** bytes in the record.
+  **
+  ** zRec is set to be the complete text of the record if it is available.
+  ** The complete record text is always available for pseudo-tables
+  ** If the record is stored in a cursor, the complete record text
+  ** might be available in the  pC->aRow cache.  Or it might not be.
+  ** If the data is unavailable,  zRec is set to NULL.
+  **
+  ** We also compute the number of columns in the record.  For cursors,
+  ** the number of columns is stored in the Cursor.nField element.
+  */
+  pC = p->apCsr[p1];
+  assert( pC!=0 );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  assert( pC->pVtabCursor==0 );
+#endif
+  if( pC->pCursor!=0 ){
+    /* The record is stored in a B-Tree */
+    rc = sqlite3VdbeCursorMoveto(pC);
+    if( rc ) goto abort_due_to_error;
+    zRec = 0;
+    pCrsr = pC->pCursor;
+    if( pC->nullRow ){
+      payloadSize = 0;
+    }else if( pC->cacheStatus==p->cacheCtr ){
+      payloadSize = pC->payloadSize;
+      zRec = (char*)pC->aRow;
+    }else if( pC->isIndex ){
+      i64 payloadSize64;
+      sqlite3BtreeKeySize(pCrsr, &payloadSize64);
+      payloadSize = payloadSize64;
+    }else{
+      sqlite3BtreeDataSize(pCrsr, &payloadSize);
+    }
+    nField = pC->nField;
+  }else{
+    assert( pC->pseudoTable );
+    /* The record is the sole entry of a pseudo-table */
+    payloadSize = pC->nData;
+    zRec = pC->pData;
+    pC->cacheStatus = CACHE_STALE;
+    assert( payloadSize==0 || zRec!=0 );
+    nField = pC->nField;
+    pCrsr = 0;
+  }
+
+  /* If payloadSize is 0, then just store a NULL */
+  if( payloadSize==0 ){
+    assert( pDest->flags&MEM_Null );
+    goto op_column_out;
+  }
+  if( payloadSize>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+
+  assert( p2<nField );
+
+  /* Read and parse the table header.  Store the results of the parse
+  ** into the record header cache fields of the cursor.
+  */
+  aType = pC->aType;
+  if( pC->cacheStatus==p->cacheCtr ){
+    aOffset = pC->aOffset;
+  }else{
+    u8 *zIdx;        /* Index into header */
+    u8 *zEndHdr;     /* Pointer to first byte after the header */
+    u32 offset;      /* Offset into the data */
+    int szHdrSz;     /* Size of the header size field at start of record */
+    int avail;       /* Number of bytes of available data */
+
+    assert(aType);
+    pC->aOffset = aOffset = &aType[nField];
+    pC->payloadSize = payloadSize;
+    pC->cacheStatus = p->cacheCtr;
+
+    /* Figure out how many bytes are in the header */
+    if( zRec ){
+      zData = zRec;
+    }else{
+      if( pC->isIndex ){
+        zData = (char*)sqlite3BtreeKeyFetch(pCrsr, &avail);
+      }else{
+        zData = (char*)sqlite3BtreeDataFetch(pCrsr, &avail);
+      }
+      /* If KeyFetch()/DataFetch() managed to get the entire payload,
+      ** save the payload in the pC->aRow cache.  That will save us from
+      ** having to make additional calls to fetch the content portion of
+      ** the record.
+      */
+      if( avail>=payloadSize ){
+        zRec = zData;
+        pC->aRow = (u8*)zData;
+      }else{
+        pC->aRow = 0;
+      }
+    }
+    /* The following assert is true in all cases accept when
+    ** the database file has been corrupted externally.
+    **    assert( zRec!=0 || avail>=payloadSize || avail>=9 ); */
+    szHdrSz = getVarint32((u8*)zData, offset);
+
+    /* The KeyFetch() or DataFetch() above are fast and will get the entire
+    ** record header in most cases.  But they will fail to get the complete
+    ** record header if the record header does not fit on a single page
+    ** in the B-Tree.  When that happens, use sqlite3VdbeMemFromBtree() to
+    ** acquire the complete header text.
+    */
+    if( !zRec && avail<offset ){
+      sMem.flags = 0;
+      sMem.db = 0;
+      rc = sqlite3VdbeMemFromBtree(pCrsr, 0, offset, pC->isIndex, &sMem);
+      if( rc!=SQLITE_OK ){
+        goto op_column_out;
+      }
+      zData = sMem.z;
+    }
+    zEndHdr = (u8 *)&zData[offset];
+    zIdx = (u8 *)&zData[szHdrSz];
+
+    /* Scan the header and use it to fill in the aType[] and aOffset[]
+    ** arrays.  aType[i] will contain the type integer for the i-th
+    ** column and aOffset[i] will contain the offset from the beginning
+    ** of the record to the start of the data for the i-th column
+    */
+    for(i=0; i<nField; i++){
+      if( zIdx<zEndHdr ){
+        aOffset[i] = offset;
+        zIdx += getVarint32(zIdx, aType[i]);
+        offset += sqlite3VdbeSerialTypeLen(aType[i]);
+      }else{
+        /* If i is less that nField, then there are less fields in this
+        ** record than SetNumColumns indicated there are columns in the
+        ** table. Set the offset for any extra columns not present in
+        ** the record to 0. This tells code below to store a NULL
+        ** instead of deserializing a value from the record.
+        */
+        aOffset[i] = 0;
+      }
+    }
+    sqlite3VdbeMemRelease(&sMem);
+    sMem.flags = MEM_Null;
+
+    /* If we have read more header data than was contained in the header,
+    ** or if the end of the last field appears to be past the end of the
+    ** record, or if the end of the last field appears to be before the end
+    ** of the record (when all fields present), then we must be dealing 
+    ** with a corrupt database.
+    */
+    if( zIdx>zEndHdr || offset>payloadSize || (zIdx==zEndHdr && offset!=payloadSize) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto op_column_out;
+    }
+  }
+
+  /* Get the column information. If aOffset[p2] is non-zero, then 
+  ** deserialize the value from the record. If aOffset[p2] is zero,
+  ** then there are not enough fields in the record to satisfy the
+  ** request.  In this case, set the value NULL or to P4 if P4 is
+  ** a pointer to a Mem object.
+  */
+  if( aOffset[p2] ){
+    assert( rc==SQLITE_OK );
+    if( zRec ){
+      if( pDest->flags&MEM_Dyn ){
+        sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], &sMem);
+        sMem.db = db; 
+        rc = sqlite3VdbeMemCopy(pDest, &sMem);
+        assert( !(sMem.flags&MEM_Dyn) );
+        if( rc!=SQLITE_OK ){
+          goto op_column_out;
+        }
+      }else{
+        sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
+      }
+    }else{
+      len = sqlite3VdbeSerialTypeLen(aType[p2]);
+      sqlite3VdbeMemMove(&sMem, pDest);
+      rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
+      if( rc!=SQLITE_OK ){
+        goto op_column_out;
+      }
+      zData = sMem.z;
+      sqlite3VdbeSerialGet((u8*)zData, aType[p2], pDest);
+    }
+    pDest->enc = encoding;
+  }else{
+    if( pOp->p4type==P4_MEM ){
+      sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
+    }else{
+      assert( pDest->flags&MEM_Null );
+    }
+  }
+
+  /* If we dynamically allocated space to hold the data (in the
+  ** sqlite3VdbeMemFromBtree() call above) then transfer control of that
+  ** dynamically allocated space over to the pDest structure.
+  ** This prevents a memory copy.
+  */
+  if( sMem.zMalloc ){
+    assert( sMem.z==sMem.zMalloc );
+    assert( !(pDest->flags & MEM_Dyn) );
+    assert( !(pDest->flags & (MEM_Blob|MEM_Str)) || pDest->z==sMem.z );
+    pDest->flags &= ~(MEM_Ephem|MEM_Static);
+    pDest->flags |= MEM_Term;
+    pDest->z = sMem.z;
+    pDest->zMalloc = sMem.zMalloc;
+  }
+
+  rc = sqlite3VdbeMemMakeWriteable(pDest);
+
+op_column_out:
+  UPDATE_MAX_BLOBSIZE(pDest);
+  REGISTER_TRACE(pOp->p3, pDest);
+  break;
+}
+
+/* Opcode: Affinity P1 P2 * P4 *
+**
+** Apply affinities to a range of P2 registers starting with P1.
+**
+** P4 is a string that is P2 characters long. The nth character of the
+** string indicates the column affinity that should be used for the nth
+** memory cell in the range.
+*/
+case OP_Affinity: {
+  char *zAffinity = pOp->p4.z;
+  Mem *pData0 = &p->aMem[pOp->p1];
+  Mem *pLast = &pData0[pOp->p2-1];
+  Mem *pRec;
+
+  for(pRec=pData0; pRec<=pLast; pRec++){
+    ExpandBlob(pRec);
+    applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
+  }
+  break;
+}
+
+/* Opcode: MakeRecord P1 P2 P3 P4 *
+**
+** Convert P2 registers beginning with P1 into a single entry
+** suitable for use as a data record in a database table or as a key
+** in an index.  The details of the format are irrelavant as long as
+** the OP_Column opcode can decode the record later.
+** Refer to source code comments for the details of the record
+** format.
+**
+** P4 may be a string that is P2 characters long.  The nth character of the
+** string indicates the column affinity that should be used for the nth
+** field of the index key.
+**
+** The mapping from character to affinity is given by the SQLITE_AFF_
+** macros defined in sqliteInt.h.
+**
+** If P4 is NULL then all index fields have the affinity NONE.
+*/
+case OP_MakeRecord: {
+  /* Assuming the record contains N fields, the record format looks
+  ** like this:
+  **
+  ** ------------------------------------------------------------------------
+  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 
+  ** ------------------------------------------------------------------------
+  **
+  ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
+  ** and so froth.
+  **
+  ** Each type field is a varint representing the serial type of the 
+  ** corresponding data element (see sqlite3VdbeSerialType()). The
+  ** hdr-size field is also a varint which is the offset from the beginning
+  ** of the record to data0.
+  */
+  u8 *zNewRecord;        /* A buffer to hold the data for the new record */
+  Mem *pRec;             /* The new record */
+  u64 nData = 0;         /* Number of bytes of data space */
+  int nHdr = 0;          /* Number of bytes of header space */
+  u64 nByte = 0;         /* Data space required for this record */
+  int nZero = 0;         /* Number of zero bytes at the end of the record */
+  int nVarint;           /* Number of bytes in a varint */
+  u32 serial_type;       /* Type field */
+  Mem *pData0;           /* First field to be combined into the record */
+  Mem *pLast;            /* Last field of the record */
+  int nField;            /* Number of fields in the record */
+  char *zAffinity;       /* The affinity string for the record */
+  int file_format;       /* File format to use for encoding */
+  int i;                 /* Space used in zNewRecord[] */
+
+  nField = pOp->p1;
+  zAffinity = pOp->p4.z;
+  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=p->nMem );
+  pData0 = &p->aMem[nField];
+  nField = pOp->p2;
+  pLast = &pData0[nField-1];
+  file_format = p->minWriteFileFormat;
+
+  /* Loop through the elements that will make up the record to figure
+  ** out how much space is required for the new record.
+  */
+  for(pRec=pData0; pRec<=pLast; pRec++){
+    int len;
+    if( zAffinity ){
+      applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
+    }
+    if( pRec->flags&MEM_Zero && pRec->n>0 ){
+      sqlite3VdbeMemExpandBlob(pRec);
+    }
+    serial_type = sqlite3VdbeSerialType(pRec, file_format);
+    len = sqlite3VdbeSerialTypeLen(serial_type);
+    nData += len;
+    nHdr += sqlite3VarintLen(serial_type);
+    if( pRec->flags & MEM_Zero ){
+      /* Only pure zero-filled BLOBs can be input to this Opcode.
+      ** We do not allow blobs with a prefix and a zero-filled tail. */
+      nZero += pRec->u.i;
+    }else if( len ){
+      nZero = 0;
+    }
+  }
+
+  /* Add the initial header varint and total the size */
+  nHdr += nVarint = sqlite3VarintLen(nHdr);
+  if( nVarint<sqlite3VarintLen(nHdr) ){
+    nHdr++;
+  }
+  nByte = nHdr+nData-nZero;
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+
+  /* Make sure the output register has a buffer large enough to store 
+  ** the new record. The output register (pOp->p3) is not allowed to
+  ** be one of the input registers (because the following call to
+  ** sqlite3VdbeMemGrow() could clobber the value before it is used).
+  */
+  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
+  pOut = &p->aMem[pOp->p3];
+  if( sqlite3VdbeMemGrow(pOut, nByte, 0) ){
+    goto no_mem;
+  }
+  zNewRecord = (u8 *)pOut->z;
+
+  /* Write the record */
+  i = putVarint32(zNewRecord, nHdr);
+  for(pRec=pData0; pRec<=pLast; pRec++){
+    serial_type = sqlite3VdbeSerialType(pRec, file_format);
+    i += putVarint32(&zNewRecord[i], serial_type);      /* serial type */
+  }
+  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
+    i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRec, file_format);
+  }
+  assert( i==nByte );
+
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pOut->n = nByte;
+  pOut->flags = MEM_Blob | MEM_Dyn;
+  pOut->xDel = 0;
+  if( nZero ){
+    pOut->u.i = nZero;
+    pOut->flags |= MEM_Zero;
+  }
+  pOut->enc = SQLITE_UTF8;  /* In case the blob is ever converted to text */
+  REGISTER_TRACE(pOp->p3, pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Statement P1 * * * *
+**
+** Begin an individual statement transaction which is part of a larger
+** transaction.  This is needed so that the statement
+** can be rolled back after an error without having to roll back the
+** entire transaction.  The statement transaction will automatically
+** commit when the VDBE halts.
+**
+** If the database connection is currently in autocommit mode (that 
+** is to say, if it is in between BEGIN and COMMIT)
+** and if there are no other active statements on the same database
+** connection, then this operation is a no-op.  No statement transaction
+** is needed since any error can use the normal ROLLBACK process to
+** undo changes.
+**
+** If a statement transaction is started, then a statement journal file
+** will be allocated and initialized.
+**
+** The statement is begun on the database file with index P1.  The main
+** database file has an index of 0 and the file used for temporary tables
+** has an index of 1.
+*/
+case OP_Statement: {
+  if( db->autoCommit==0 || db->activeVdbeCnt>1 ){
+    int i = pOp->p1;
+    Btree *pBt;
+    assert( i>=0 && i<db->nDb );
+    assert( db->aDb[i].pBt!=0 );
+    pBt = db->aDb[i].pBt;
+    assert( sqlite3BtreeIsInTrans(pBt) );
+    assert( (p->btreeMask & (1<<i))!=0 );
+    if( !sqlite3BtreeIsInStmt(pBt) ){
+      rc = sqlite3BtreeBeginStmt(pBt);
+      p->openedStatement = 1;
+    }
+  }
+  break;
+}
+
+/* Opcode: AutoCommit P1 P2 * * *
+**
+** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
+** back any currently active btree transactions. If there are any active
+** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
+**
+** This instruction causes the VM to halt.
+*/
+case OP_AutoCommit: {
+  u8 i = pOp->p1;
+  u8 rollback = pOp->p2;
+
+  assert( i==1 || i==0 );
+  assert( i==1 || rollback==0 );
+
+  assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */
+
+  if( db->activeVdbeCnt>1 && i && !db->autoCommit ){
+    /* If this instruction implements a COMMIT or ROLLBACK, other VMs are
+    ** still running, and a transaction is active, return an error indicating
+    ** that the other VMs must complete first. 
+    */
+    sqlite3SetString(&p->zErrMsg, "cannot ", rollback?"rollback":"commit", 
+        " transaction - SQL statements in progress", (char*)0);
+    rc = SQLITE_ERROR;
+  }else if( i!=db->autoCommit ){
+    if( pOp->p2 ){
+      assert( i==1 );
+      sqlite3RollbackAll(db);
+      db->autoCommit = 1;
+    }else{
+      db->autoCommit = i;
+      if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+        p->pc = pc;
+        db->autoCommit = 1-i;
+        p->rc = rc = SQLITE_BUSY;
+        goto vdbe_return;
+      }
+    }
+    if( p->rc==SQLITE_OK ){
+      rc = SQLITE_DONE;
+    }else{
+      rc = SQLITE_ERROR;
+    }
+    goto vdbe_return;
+  }else{
+    sqlite3SetString(&p->zErrMsg,
+        (!i)?"cannot start a transaction within a transaction":(
+        (rollback)?"cannot rollback - no transaction is active":
+                   "cannot commit - no transaction is active"), (char*)0);
+         
+    rc = SQLITE_ERROR;
+  }
+  break;
+}
+
+/* Opcode: Transaction P1 P2 * * *
+**
+** Begin a transaction.  The transaction ends when a Commit or Rollback
+** opcode is encountered.  Depending on the ON CONFLICT setting, the
+** transaction might also be rolled back if an error is encountered.
+**
+** P1 is the index of the database file on which the transaction is
+** started.  Index 0 is the main database file and index 1 is the
+** file used for temporary tables.  Indices of 2 or more are used for
+** attached databases.
+**
+** If P2 is non-zero, then a write-transaction is started.  A RESERVED lock is
+** obtained on the database file when a write-transaction is started.  No
+** other process can start another write transaction while this transaction is
+** underway.  Starting a write transaction also creates a rollback journal. A
+** write transaction must be started before any changes can be made to the
+** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
+** on the file.
+**
+** If P2 is zero, then a read-lock is obtained on the database file.
+*/
+case OP_Transaction: {
+  int i = pOp->p1;
+  Btree *pBt;
+
+  assert( i>=0 && i<db->nDb );
+  assert( (p->btreeMask & (1<<i))!=0 );
+  pBt = db->aDb[i].pBt;
+
+  if( pBt ){
+    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
+    if( rc==SQLITE_BUSY ){
+      p->pc = pc;
+      p->rc = rc = SQLITE_BUSY;
+      goto vdbe_return;
+    }
+    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY /* && rc!=SQLITE_BUSY */ ){
+      goto abort_due_to_error;
+    }
+  }
+  break;
+}
+
+/* Opcode: ReadCookie P1 P2 P3 * *
+**
+** Read cookie number P3 from database P1 and write it into register P2.
+** P3==0 is the schema version.  P3==1 is the database format.
+** P3==2 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** If P1 is negative, then this is a request to read the size of a
+** databases free-list. P3 must be set to 1 in this case. The actual
+** database accessed is ((P1+1)*-1). For example, a P1 parameter of -1
+** corresponds to database 0 ("main"), a P1 of -2 is database 1 ("temp").
+**
+** There must be a read-lock on the database (either a transaction
+** must be started or there must be an open cursor) before
+** executing this instruction.
+*/
+case OP_ReadCookie: {               /* out2-prerelease */
+  int iMeta;
+  int iDb = pOp->p1;
+  int iCookie = pOp->p3;
+
+  assert( pOp->p3<SQLITE_N_BTREE_META );
+  if( iDb<0 ){
+    iDb = (-1*(iDb+1));
+    iCookie *= -1;
+  }
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+  assert( (p->btreeMask & (1<<iDb))!=0 );
+  /* The indexing of meta values at the schema layer is off by one from
+  ** the indexing in the btree layer.  The btree considers meta[0] to
+  ** be the number of free pages in the database (a read-only value)
+  ** and meta[1] to be the schema cookie.  The schema layer considers
+  ** meta[1] to be the schema cookie.  So we have to shift the index
+  ** by one in the following statement.
+  */
+  rc = sqlite3BtreeGetMeta(db->aDb[iDb].pBt, 1 + iCookie, (u32 *)&iMeta);
+  pOut->u.i = iMeta;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+/* Opcode: SetCookie P1 P2 P3 * *
+**
+** Write the content of register P3 (interpreted as an integer)
+** into cookie number P2 of database P1.
+** P2==0 is the schema version.  P2==1 is the database format.
+** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** A transaction must be started before executing this opcode.
+*/
+case OP_SetCookie: {       /* in3 */
+  Db *pDb;
+  assert( pOp->p2<SQLITE_N_BTREE_META );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  sqlite3VdbeMemIntegerify(pIn3);
+  /* See note about index shifting on OP_ReadCookie */
+  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pIn3->u.i);
+  if( pOp->p2==0 ){
+    /* When the schema cookie changes, record the new cookie internally */
+    pDb->pSchema->schema_cookie = pIn3->u.i;
+    db->flags |= SQLITE_InternChanges;
+  }else if( pOp->p2==1 ){
+    /* Record changes in the file format */
+    pDb->pSchema->file_format = pIn3->u.i;
+  }
+  if( pOp->p1==1 ){
+    /* Invalidate all prepared statements whenever the TEMP database
+    ** schema is changed.  Ticket #1644 */
+    sqlite3ExpirePreparedStatements(db);
+  }
+  break;
+}
+
+/* Opcode: VerifyCookie P1 P2 *
+**
+** Check the value of global database parameter number 0 (the
+** schema version) and make sure it is equal to P2.  
+** P1 is the database number which is 0 for the main database file
+** and 1 for the file holding temporary tables and some higher number
+** for auxiliary databases.
+**
+** The cookie changes its value whenever the database schema changes.
+** This operation is used to detect when that the cookie has changed
+** and that the current process needs to reread the schema.
+**
+** Either a transaction needs to have been started or an OP_Open needs
+** to be executed (to establish a read lock) before this opcode is
+** invoked.
+*/
+case OP_VerifyCookie: {
+  int iMeta;
+  Btree *pBt;
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+  pBt = db->aDb[pOp->p1].pBt;
+  if( pBt ){
+    rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&iMeta);
+  }else{
+    rc = SQLITE_OK;
+    iMeta = 0;
+  }
+  if( rc==SQLITE_OK && iMeta!=pOp->p2 ){
+    sqlite3_free(p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
+    /* If the schema-cookie from the database file matches the cookie 
+    ** stored with the in-memory representation of the schema, do
+    ** not reload the schema from the database file.
+    **
+    ** If virtual-tables are in use, this is not just an optimisation.
+    ** Often, v-tables store their data in other SQLite tables, which
+    ** are queried from within xNext() and other v-table methods using
+    ** prepared queries. If such a query is out-of-date, we do not want to
+    ** discard the database schema, as the user code implementing the
+    ** v-table would have to be ready for the sqlite3_vtab structure itself
+    ** to be invalidated whenever sqlite3_step() is called from within 
+    ** a v-table method.
+    */
+    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
+      sqlite3ResetInternalSchema(db, pOp->p1);
+    }
+
+    sqlite3ExpirePreparedStatements(db);
+    rc = SQLITE_SCHEMA;
+  }
+  break;
+}
+
+/* Opcode: OpenRead P1 P2 P3 P4 P5
+**
+** Open a read-only cursor for the database table whose root page is
+** P2 in a database file.  The database file is determined by P3. 
+** P3==0 means the main database, P3==1 means the database used for 
+** temporary tables, and P3>1 means used the corresponding attached
+** database.  Give the new cursor an identifier of P1.  The P1
+** values need not be contiguous but all P1 values should be small integers.
+** It is an error for P1 to be negative.
+**
+** If P5!=0 then use the content of register P2 as the root page, not
+** the value of P2 itself.
+**
+** There will be a read lock on the database whenever there is an
+** open cursor.  If the database was unlocked prior to this instruction
+** then a read lock is acquired as part of this instruction.  A read
+** lock allows other processes to read the database but prohibits
+** any other process from modifying the database.  The read lock is
+** released when all cursors are closed.  If this instruction attempts
+** to get a read lock but fails, the script terminates with an
+** SQLITE_BUSY error code.
+**
+** The P4 value is a pointer to a KeyInfo structure that defines the
+** content and collating sequence of indices.  P4 is NULL for cursors
+** that are not pointing to indices.
+**
+** See also OpenWrite.
+*/
+/* Opcode: OpenWrite P1 P2 P3 P4 P5
+**
+** Open a read/write cursor named P1 on the table or index whose root
+** page is P2.  Or if P5!=0 use the content of register P2 to find the
+** root page.
+**
+** The P4 value is a pointer to a KeyInfo structure that defines the
+** content and collating sequence of indices.  P4 is NULL for cursors
+** that are not pointing to indices.
+**
+** This instruction works just like OpenRead except that it opens the cursor
+** in read/write mode.  For a given table, there can be one or more read-only
+** cursors or a single read/write cursor but not both.
+**
+** See also OpenRead.
+*/
+case OP_OpenRead:
+case OP_OpenWrite: {
+  int i = pOp->p1;
+  int p2 = pOp->p2;
+  int iDb = pOp->p3;
+  int wrFlag;
+  Btree *pX;
+  Cursor *pCur;
+  Db *pDb;
+  
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( (p->btreeMask & (1<<iDb))!=0 );
+  pDb = &db->aDb[iDb];
+  pX = pDb->pBt;
+  assert( pX!=0 );
+  if( pOp->opcode==OP_OpenWrite ){
+    wrFlag = 1;
+    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
+      p->minWriteFileFormat = pDb->pSchema->file_format;
+    }
+  }else{
+    wrFlag = 0;
+  }
+  if( pOp->p5 ){
+    assert( p2>0 );
+    assert( p2<=p->nMem );
+    pIn2 = &p->aMem[p2];
+    sqlite3VdbeMemIntegerify(pIn2);
+    p2 = pIn2->u.i;
+    assert( p2>=2 );
+  }
+  assert( i>=0 );
+  pCur = allocateCursor(p, i, &pOp[-1], iDb, 1);
+  if( pCur==0 ) goto no_mem;
+  pCur->nullRow = 1;
+  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pOp->p4.p, pCur->pCursor);
+  if( pOp->p4type==P4_KEYINFO ){
+    pCur->pKeyInfo = pOp->p4.pKeyInfo;
+    pCur->pIncrKey = &pCur->pKeyInfo->incrKey;
+    pCur->pKeyInfo->enc = ENC(p->db);
+  }else{
+    pCur->pKeyInfo = 0;
+    pCur->pIncrKey = &pCur->bogusIncrKey;
+  }
+  switch( rc ){
+    case SQLITE_BUSY: {
+      p->pc = pc;
+      p->rc = rc = SQLITE_BUSY;
+      goto vdbe_return;
+    }
+    case SQLITE_OK: {
+      int flags = sqlite3BtreeFlags(pCur->pCursor);
+      /* Sanity checking.  Only the lower four bits of the flags byte should
+      ** be used.  Bit 3 (mask 0x08) is unpreditable.  The lower 3 bits
+      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
+      ** 2 (zerodata for indices).  If these conditions are not met it can
+      ** only mean that we are dealing with a corrupt database file
+      */
+      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
+        rc = SQLITE_CORRUPT_BKPT;
+        goto abort_due_to_error;
+      }
+      pCur->isTable = (flags & BTREE_INTKEY)!=0;
+      pCur->isIndex = (flags & BTREE_ZERODATA)!=0;
+      /* If P4==0 it means we are expected to open a table.  If P4!=0 then
+      ** we expect to be opening an index.  If this is not what happened,
+      ** then the database is corrupt
+      */
+      if( (pCur->isTable && pOp->p4type==P4_KEYINFO)
+       || (pCur->isIndex && pOp->p4type!=P4_KEYINFO) ){
+        rc = SQLITE_CORRUPT_BKPT;
+        goto abort_due_to_error;
+      }
+      break;
+    }
+    case SQLITE_EMPTY: {
+      pCur->isTable = pOp->p4type!=P4_KEYINFO;
+      pCur->isIndex = !pCur->isTable;
+      pCur->pCursor = 0;
+      rc = SQLITE_OK;
+      break;
+    }
+    default: {
+      goto abort_due_to_error;
+    }
+  }
+  break;
+}
+
+/* Opcode: OpenEphemeral P1 P2 * P4 *
+**
+** Open a new cursor P1 to a transient table.
+** The cursor is always opened read/write even if 
+** the main database is read-only.  The transient or virtual
+** table is deleted automatically when the cursor is closed.
+**
+** P2 is the number of columns in the virtual table.
+** The cursor points to a BTree table if P4==0 and to a BTree index
+** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
+** that defines the format of keys in the index.
+**
+** This opcode was once called OpenTemp.  But that created
+** confusion because the term "temp table", might refer either
+** to a TEMP table at the SQL level, or to a table opened by
+** this opcode.  Then this opcode was call OpenVirtual.  But
+** that created confusion with the whole virtual-table idea.
+*/
+case OP_OpenEphemeral: {
+  int i = pOp->p1;
+  Cursor *pCx;
+  static const int openFlags = 
+      SQLITE_OPEN_READWRITE |
+      SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE |
+      SQLITE_OPEN_DELETEONCLOSE |
+      SQLITE_OPEN_TRANSIENT_DB;
+
+  assert( i>=0 );
+  pCx = allocateCursor(p, i, pOp, -1, 1);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  rc = sqlite3BtreeFactory(db, 0, 1, SQLITE_DEFAULT_TEMP_CACHE_SIZE, openFlags,
+                           &pCx->pBt);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
+  }
+  if( rc==SQLITE_OK ){
+    /* If a transient index is required, create it by calling
+    ** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
+    ** opening it. If a transient table is required, just use the
+    ** automatically created table with root-page 1 (an INTKEY table).
+    */
+    if( pOp->p4.pKeyInfo ){
+      int pgno;
+      assert( pOp->p4type==P4_KEYINFO );
+      rc = sqlite3BtreeCreateTable(pCx->pBt, &pgno, BTREE_ZERODATA); 
+      if( rc==SQLITE_OK ){
+        assert( pgno==MASTER_ROOT+1 );
+        rc = sqlite3BtreeCursor(pCx->pBt, pgno, 1, 
+                                (KeyInfo*)pOp->p4.z, pCx->pCursor);
+        pCx->pKeyInfo = pOp->p4.pKeyInfo;
+        pCx->pKeyInfo->enc = ENC(p->db);
+        pCx->pIncrKey = &pCx->pKeyInfo->incrKey;
+      }
+      pCx->isTable = 0;
+    }else{
+      rc = sqlite3BtreeCursor(pCx->pBt, MASTER_ROOT, 1, 0, pCx->pCursor);
+      pCx->isTable = 1;
+      pCx->pIncrKey = &pCx->bogusIncrKey;
+    }
+  }
+  pCx->isIndex = !pCx->isTable;
+  break;
+}
+
+/* Opcode: OpenPseudo P1 P2 * * *
+**
+** Open a new cursor that points to a fake table that contains a single
+** row of data.  Any attempt to write a second row of data causes the
+** first row to be deleted.  All data is deleted when the cursor is
+** closed.
+**
+** A pseudo-table created by this opcode is useful for holding the
+** NEW or OLD tables in a trigger.  Also used to hold the a single
+** row output from the sorter so that the row can be decomposed into
+** individual columns using the OP_Column opcode.
+**
+** When OP_Insert is executed to insert a row in to the pseudo table,
+** the pseudo-table cursor may or may not make it's own copy of the
+** original row data. If P2 is 0, then the pseudo-table will copy the
+** original row data. Otherwise, a pointer to the original memory cell
+** is stored. In this case, the vdbe program must ensure that the 
+** memory cell containing the row data is not overwritten until the
+** pseudo table is closed (or a new row is inserted into it).
+*/
+case OP_OpenPseudo: {
+  int i = pOp->p1;
+  Cursor *pCx;
+  assert( i>=0 );
+  pCx = allocateCursor(p, i, &pOp[-1], -1, 0);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  pCx->pseudoTable = 1;
+  pCx->ephemPseudoTable = pOp->p2;
+  pCx->pIncrKey = &pCx->bogusIncrKey;
+  pCx->isTable = 1;
+  pCx->isIndex = 0;
+  break;
+}
+
+/* Opcode: Close P1 * * * *
+**
+** Close a cursor previously opened as P1.  If P1 is not
+** currently open, this instruction is a no-op.
+*/
+case OP_Close: {
+  int i = pOp->p1;
+  assert( i>=0 && i<p->nCursor );
+  sqlite3VdbeFreeCursor(p, p->apCsr[i]);
+  p->apCsr[i] = 0;
+  break;
+}
+
+/* Opcode: MoveGe P1 P2 P3 P4 *
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
+** use the integer value in register P3 as a key. If cursor P1 refers 
+** to an SQL index, then P3 is the first in an array of P4 registers 
+** that are used as an unpacked index key. 
+**
+** Reposition cursor P1 so that  it points to the smallest entry that 
+** is greater than or equal to the key value. If there are no records 
+** greater than or equal to the key and P2 is not zero, then jump to P2.
+**
+** A special feature of this opcode (and different from the
+** related OP_MoveGt, OP_MoveLt, and OP_MoveLe) is that if P2 is
+** zero and P1 is an SQL table (a b-tree with integer keys) then
+** the seek is deferred until it is actually needed.  It might be
+** the case that the cursor is never accessed.  By deferring the
+** seek, we avoid unnecessary seeks.
+**
+** See also: Found, NotFound, Distinct, MoveLt, MoveGt, MoveLe
+*/
+/* Opcode: MoveGt P1 P2 P3 P4 *
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
+** use the integer value in register P3 as a key. If cursor P1 refers 
+** to an SQL index, then P3 is the first in an array of P4 registers 
+** that are used as an unpacked index key. 
+**
+** Reposition cursor P1 so that  it points to the smallest entry that 
+** is greater than the key value. If there are no records greater than 
+** the key and P2 is not zero, then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveLt, MoveGe, MoveLe
+*/
+/* Opcode: MoveLt P1 P2 P3 P4 * 
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
+** use the integer value in register P3 as a key. If cursor P1 refers 
+** to an SQL index, then P3 is the first in an array of P4 registers 
+** that are used as an unpacked index key. 
+**
+** Reposition cursor P1 so that  it points to the largest entry that 
+** is less than the key value. If there are no records less than 
+** the key and P2 is not zero, then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLe
+*/
+/* Opcode: MoveLe P1 P2 P3 P4 *
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
+** use the integer value in register P3 as a key. If cursor P1 refers 
+** to an SQL index, then P3 is the first in an array of P4 registers 
+** that are used as an unpacked index key. 
+**
+** Reposition cursor P1 so that it points to the largest entry that 
+** is less than or equal to the key value. If there are no records 
+** less than or equal to the key and P2 is not zero, then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLt
+*/
+case OP_MoveLt:         /* jump, in3 */
+case OP_MoveLe:         /* jump, in3 */
+case OP_MoveGe:         /* jump, in3 */
+case OP_MoveGt: {       /* jump, in3 */
+  int i = pOp->p1;
+  Cursor *pC;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  if( pC->pCursor!=0 ){
+    int res, oc;
+    oc = pOp->opcode;
+    pC->nullRow = 0;
+    *pC->pIncrKey = oc==OP_MoveGt || oc==OP_MoveLe;
+    if( pC->isTable ){
+      i64 iKey = sqlite3VdbeIntValue(pIn3);
+      if( pOp->p2==0 ){
+        assert( pOp->opcode==OP_MoveGe );
+        pC->movetoTarget = iKey;
+        pC->rowidIsValid = 0;
+        pC->deferredMoveto = 1;
+        break;
+      }
+      rc = sqlite3BtreeMoveto(pC->pCursor, 0, 0, (u64)iKey, 0, &res);
+      if( rc!=SQLITE_OK ){
+        goto abort_due_to_error;
+      }
+      pC->lastRowid = iKey;
+      pC->rowidIsValid = res==0;
+    }else{
+      UnpackedRecord r;
+      int nField = pOp->p4.i;
+      assert( pOp->p4type==P4_INT32 );
+      assert( nField>0 );
+      r.pKeyInfo = pC->pKeyInfo;
+      r.nField = nField;
+      r.needFree = 0;
+      r.needDestroy = 0;
+      r.aMem = &p->aMem[pOp->p3];
+      rc = sqlite3BtreeMoveto(pC->pCursor, 0, &r, 0, 0, &res);
+      if( rc!=SQLITE_OK ){
+        goto abort_due_to_error;
+      }
+      pC->rowidIsValid = 0;
+    }
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+    *pC->pIncrKey = 0;
+#ifdef SQLITE_TEST
+    sqlite3_search_count++;
+#endif
+    if( oc==OP_MoveGe || oc==OP_MoveGt ){
+      if( res<0 ){
+        rc = sqlite3BtreeNext(pC->pCursor, &res);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+        pC->rowidIsValid = 0;
+      }else{
+        res = 0;
+      }
+    }else{
+      assert( oc==OP_MoveLt || oc==OP_MoveLe );
+      if( res>=0 ){
+        rc = sqlite3BtreePrevious(pC->pCursor, &res);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+        pC->rowidIsValid = 0;
+      }else{
+        /* res might be negative because the table is empty.  Check to
+        ** see if this is the case.
+        */
+        res = sqlite3BtreeEof(pC->pCursor);
+      }
+    }
+    assert( pOp->p2>0 );
+    if( res ){
+      pc = pOp->p2 - 1;
+    }
+  }
+  break;
+}
+
+/* Opcode: Found P1 P2 P3 * *
+**
+** Register P3 holds a blob constructed by MakeRecord.  P1 is an index.
+** If an entry that matches the value in register p3 exists in P1 then
+** jump to P2.  If the P3 value does not match any entry in P1
+** then fall thru.  The P1 cursor is left pointing at the matching entry
+** if it exists.
+**
+** This instruction is used to implement the IN operator where the
+** left-hand side is a SELECT statement.  P1 may be a true index, or it
+** may be a temporary index that holds the results of the SELECT
+** statement.   This instruction is also used to implement the
+** DISTINCT keyword in SELECT statements.
+**
+** This instruction checks if index P1 contains a record for which 
+** the first N serialised values exactly match the N serialised values
+** in the record in register P3, where N is the total number of values in
+** the P3 record (the P3 record is a prefix of the P1 record). 
+**
+** See also: NotFound, MoveTo, IsUnique, NotExists
+*/
+/* Opcode: NotFound P1 P2 P3 * *
+**
+** Register P3 holds a blob constructed by MakeRecord.  P1 is
+** an index.  If no entry exists in P1 that matches the blob then jump
+** to P2.  If an entry does existing, fall through.  The cursor is left
+** pointing to the entry that matches.
+**
+** See also: Found, MoveTo, NotExists, IsUnique
+*/
+case OP_NotFound:       /* jump, in3 */
+case OP_Found: {        /* jump, in3 */
+  int i = pOp->p1;
+  int alreadyExists = 0;
+  Cursor *pC;
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pC = p->apCsr[i])->pCursor!=0 ){
+    int res;
+    assert( pC->isTable==0 );
+    assert( pIn3->flags & MEM_Blob );
+    if( pOp->opcode==OP_Found ){
+      pC->pKeyInfo->prefixIsEqual = 1;
+    }
+    rc = sqlite3BtreeMoveto(pC->pCursor, pIn3->z, 0, pIn3->n, 0, &res);
+    pC->pKeyInfo->prefixIsEqual = 0;
+    if( rc!=SQLITE_OK ){
+      break;
+    }
+    alreadyExists = (res==0);
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  if( pOp->opcode==OP_Found ){
+    if( alreadyExists ) pc = pOp->p2 - 1;
+  }else{
+    if( !alreadyExists ) pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: IsUnique P1 P2 P3 P4 *
+**
+** The P3 register contains an integer record number.  Call this
+** record number R.  The P4 register contains an index key created
+** using MakeIdxRec.  Call it K.
+**
+** P1 is an index.  So it has no data and its key consists of a
+** record generated by OP_MakeRecord where the last field is the 
+** rowid of the entry that the index refers to.
+** 
+** This instruction asks if there is an entry in P1 where the
+** fields matches K but the rowid is different from R.
+** If there is no such entry, then there is an immediate
+** jump to P2.  If any entry does exist where the index string
+** matches K but the record number is not R, then the record
+** number for that entry is written into P3 and control
+** falls through to the next instruction.
+**
+** See also: NotFound, NotExists, Found
+*/
+case OP_IsUnique: {        /* jump, in3 */
+  int i = pOp->p1;
+  Cursor *pCx;
+  BtCursor *pCrsr;
+  Mem *pK;
+  i64 R;
+
+  /* Pop the value R off the top of the stack
+  */
+  assert( pOp->p4type==P4_INT32 );
+  assert( pOp->p4.i>0 && pOp->p4.i<=p->nMem );
+  pK = &p->aMem[pOp->p4.i];
+  sqlite3VdbeMemIntegerify(pIn3);
+  R = pIn3->u.i;
+  assert( i>=0 && i<p->nCursor );
+  pCx = p->apCsr[i];
+  assert( pCx!=0 );
+  pCrsr = pCx->pCursor;
+  if( pCrsr!=0 ){
+    int res;
+    i64 v;         /* The record number on the P1 entry that matches K */
+    char *zKey;    /* The value of K */
+    int nKey;      /* Number of bytes in K */
+    int len;       /* Number of bytes in K without the rowid at the end */
+    int szRowid;   /* Size of the rowid column at the end of zKey */
+
+    /* Make sure K is a string and make zKey point to K
+    */
+    assert( pK->flags & MEM_Blob );
+    zKey = pK->z;
+    nKey = pK->n;
+
+    szRowid = sqlite3VdbeIdxRowidLen((u8*)zKey);
+    len = nKey-szRowid;
+
+    /* Search for an entry in P1 where all but the last four bytes match K.
+    ** If there is no such entry, jump immediately to P2.
+    */
+    assert( pCx->deferredMoveto==0 );
+    pCx->cacheStatus = CACHE_STALE;
+    rc = sqlite3BtreeMoveto(pCrsr, zKey, 0, len, 0, &res);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( res<0 ){
+      rc = sqlite3BtreeNext(pCrsr, &res);
+      if( res ){
+        pc = pOp->p2 - 1;
+        break;
+      }
+    }
+    rc = sqlite3VdbeIdxKeyCompare(pCx, 0, len, (u8*)zKey, &res); 
+    if( rc!=SQLITE_OK ) goto abort_due_to_error;
+    if( res>0 ){
+      pc = pOp->p2 - 1;
+      break;
+    }
+
+    /* At this point, pCrsr is pointing to an entry in P1 where all but
+    ** the final entry (the rowid) matches K.  Check to see if the
+    ** final rowid column is different from R.  If it equals R then jump
+    ** immediately to P2.
+    */
+    rc = sqlite3VdbeIdxRowid(pCrsr, &v);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( v==R ){
+      pc = pOp->p2 - 1;
+      break;
+    }
+
+    /* The final varint of the key is different from R.  Store it back
+    ** into register R3.  (The record number of an entry that violates
+    ** a UNIQUE constraint.)
+    */
+    pIn3->u.i = v;
+    assert( pIn3->flags&MEM_Int );
+  }
+  break;
+}
+
+/* Opcode: NotExists P1 P2 P3 * *
+**
+** Use the content of register P3 as a integer key.  If a record 
+** with that key does not exist in table of P1, then jump to P2. 
+** If the record does exist, then fall thru.  The cursor is left 
+** pointing to the record if it exists.
+**
+** The difference between this operation and NotFound is that this
+** operation assumes the key is an integer and that P1 is a table whereas
+** NotFound assumes key is a blob constructed from MakeRecord and
+** P1 is an index.
+**
+** See also: Found, MoveTo, NotFound, IsUnique
+*/
+case OP_NotExists: {        /* jump, in3 */
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+    int res;
+    u64 iKey;
+    assert( pIn3->flags & MEM_Int );
+    assert( p->apCsr[i]->isTable );
+    iKey = intToKey(pIn3->u.i);
+    rc = sqlite3BtreeMoveto(pCrsr, 0, 0, iKey, 0,&res);
+    pC->lastRowid = pIn3->u.i;
+    pC->rowidIsValid = res==0;
+    pC->nullRow = 0;
+    pC->cacheStatus = CACHE_STALE;
+    /* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
+    ** processing is about to abort so we really do not care whether or not
+    ** the following jump is taken.  (In other words, do not stress over
+    ** the error that valgrind sometimes shows on the next statement when
+    ** running ioerr.test and similar failure-recovery test scripts.) */
+    if( res!=0 ){
+      pc = pOp->p2 - 1;
+      assert( pC->rowidIsValid==0 );
+    }
+  }
+  break;
+}
+
+/* Opcode: Sequence P1 P2 * * *
+**
+** Find the next available sequence number for cursor P1.
+** Write the sequence number into register P2.
+** The sequence number on the cursor is incremented after this
+** instruction.  
+*/
+case OP_Sequence: {           /* out2-prerelease */
+  int i = pOp->p1;
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  pOut->u.i = p->apCsr[i]->seqCount++;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+
+/* Opcode: NewRowid P1 P2 P3 * *
+**
+** Get a new integer record number (a.k.a "rowid") used as the key to a table.
+** The record number is not previously used as a key in the database
+** table that cursor P1 points to.  The new record number is written
+** written to register P2.
+**
+** If P3>0 then P3 is a register that holds the largest previously
+** generated record number.  No new record numbers are allowed to be less
+** than this value.  When this value reaches its maximum, a SQLITE_FULL
+** error is generated.  The P3 register is updated with the generated
+** record number.  This P3 mechanism is used to help implement the
+** AUTOINCREMENT feature.
+*/
+case OP_NewRowid: {           /* out2-prerelease */
+  int i = pOp->p1;
+  i64 v = 0;
+  Cursor *pC;
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pC = p->apCsr[i])->pCursor==0 ){
+    /* The zero initialization above is all that is needed */
+  }else{
+    /* The next rowid or record number (different terms for the same
+    ** thing) is obtained in a two-step algorithm.
+    **
+    ** First we attempt to find the largest existing rowid and add one
+    ** to that.  But if the largest existing rowid is already the maximum
+    ** positive integer, we have to fall through to the second
+    ** probabilistic algorithm
+    **
+    ** The second algorithm is to select a rowid at random and see if
+    ** it already exists in the table.  If it does not exist, we have
+    ** succeeded.  If the random rowid does exist, we select a new one
+    ** and try again, up to 1000 times.
+    **
+    ** For a table with less than 2 billion entries, the probability
+    ** of not finding a unused rowid is about 1.0e-300.  This is a 
+    ** non-zero probability, but it is still vanishingly small and should
+    ** never cause a problem.  You are much, much more likely to have a
+    ** hardware failure than for this algorithm to fail.
+    **
+    ** The analysis in the previous paragraph assumes that you have a good
+    ** source of random numbers.  Is a library function like lrand48()
+    ** good enough?  Maybe. Maybe not. It's hard to know whether there
+    ** might be subtle bugs is some implementations of lrand48() that
+    ** could cause problems. To avoid uncertainty, SQLite uses its own 
+    ** random number generator based on the RC4 algorithm.
+    **
+    ** To promote locality of reference for repetitive inserts, the
+    ** first few attempts at chosing a random rowid pick values just a little
+    ** larger than the previous rowid.  This has been shown experimentally
+    ** to double the speed of the COPY operation.
+    */
+    int res, rx=SQLITE_OK, cnt;
+    i64 x;
+    cnt = 0;
+    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
+          BTREE_INTKEY ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto abort_due_to_error;
+    }
+    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
+    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_ZERODATA)==0 );
+
+#ifdef SQLITE_32BIT_ROWID
+#   define MAX_ROWID 0x7fffffff
+#else
+    /* Some compilers complain about constants of the form 0x7fffffffffffffff.
+    ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
+    ** to provide the constant while making all compilers happy.
+    */
+#   define MAX_ROWID  ( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
+#endif
+
+    if( !pC->useRandomRowid ){
+      if( pC->nextRowidValid ){
+        v = pC->nextRowid;
+      }else{
+        rc = sqlite3BtreeLast(pC->pCursor, &res);
+        if( rc!=SQLITE_OK ){
+          goto abort_due_to_error;
+        }
+        if( res ){
+          v = 1;
+        }else{
+          sqlite3BtreeKeySize(pC->pCursor, &v);
+          v = keyToInt(v);
+          if( v==MAX_ROWID ){
+            pC->useRandomRowid = 1;
+          }else{
+            v++;
+          }
+        }
+      }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+      if( pOp->p3 ){
+        Mem *pMem;
+        assert( pOp->p3>0 && pOp->p3<=p->nMem ); /* P3 is a valid memory cell */
+        pMem = &p->aMem[pOp->p3];
+	REGISTER_TRACE(pOp->p3, pMem);
+        sqlite3VdbeMemIntegerify(pMem);
+        assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
+        if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
+          rc = SQLITE_FULL;
+          goto abort_due_to_error;
+        }
+        if( v<pMem->u.i+1 ){
+          v = pMem->u.i + 1;
+        }
+        pMem->u.i = v;
+      }
+#endif
+
+      if( v<MAX_ROWID ){
+        pC->nextRowidValid = 1;
+        pC->nextRowid = v+1;
+      }else{
+        pC->nextRowidValid = 0;
+      }
+    }
+    if( pC->useRandomRowid ){
+      assert( pOp->p3==0 );  /* SQLITE_FULL must have occurred prior to this */
+      v = db->priorNewRowid;
+      cnt = 0;
+      do{
+        if( cnt==0 && (v&0xffffff)==v ){
+          v++;
+        }else{
+          sqlite3_randomness(sizeof(v), &v);
+          if( cnt<5 ) v &= 0xffffff;
+        }
+        if( v==0 ) continue;
+        x = intToKey(v);
+        rx = sqlite3BtreeMoveto(pC->pCursor, 0, 0, (u64)x, 0, &res);
+        cnt++;
+      }while( cnt<100 && rx==SQLITE_OK && res==0 );
+      db->priorNewRowid = v;
+      if( rx==SQLITE_OK && res==0 ){
+        rc = SQLITE_FULL;
+        goto abort_due_to_error;
+      }
+    }
+    pC->rowidIsValid = 0;
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  MemSetTypeFlag(pOut, MEM_Int);
+  pOut->u.i = v;
+  break;
+}
+
+/* Opcode: Insert P1 P2 P3 P4 P5
+**
+** Write an entry into the table of cursor P1.  A new entry is
+** created if it doesn't already exist or the data for an existing
+** entry is overwritten.  The data is the value stored register
+** number P2. The key is stored in register P3. The key must
+** be an integer.
+**
+** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
+** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
+** then rowid is stored for subsequent return by the
+** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
+**
+** Parameter P4 may point to a string containing the table-name, or
+** may be NULL. If it is not NULL, then the update-hook 
+** (sqlite3.xUpdateCallback) is invoked following a successful insert.
+**
+** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
+** allocated, then ownership of P2 is transferred to the pseudo-cursor
+** and register P2 becomes ephemeral.  If the cursor is changed, the
+** value of register P2 will then change.  Make sure this does not
+** cause any problems.)
+**
+** This instruction only works on tables.  The equivalent instruction
+** for indices is OP_IdxInsert.
+*/
+case OP_Insert: {
+  Mem *pData = &p->aMem[pOp->p2];
+  Mem *pKey = &p->aMem[pOp->p3];
+
+  i64 iKey;   /* The integer ROWID or key for the record to be inserted */
+  int i = pOp->p1;
+  Cursor *pC;
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  assert( pC->pCursor!=0 || pC->pseudoTable );
+  assert( pKey->flags & MEM_Int );
+  assert( pC->isTable );
+  REGISTER_TRACE(pOp->p2, pData);
+  REGISTER_TRACE(pOp->p3, pKey);
+
+  iKey = intToKey(pKey->u.i);
+  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
+  if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = pKey->u.i;
+  if( pC->nextRowidValid && pKey->u.i>=pC->nextRowid ){
+    pC->nextRowidValid = 0;
+  }
+  if( pData->flags & MEM_Null ){
+    pData->z = 0;
+    pData->n = 0;
+  }else{
+    assert( pData->flags & (MEM_Blob|MEM_Str) );
+  }
+  if( pC->pseudoTable ){
+    if( !pC->ephemPseudoTable ){
+      sqlite3_free(pC->pData);
+    }
+    pC->iKey = iKey;
+    pC->nData = pData->n;
+    if( pData->z==pData->zMalloc || pC->ephemPseudoTable ){
+      pC->pData = pData->z;
+      if( !pC->ephemPseudoTable ){
+        pData->flags &= ~MEM_Dyn;
+        pData->flags |= MEM_Ephem;
+        pData->zMalloc = 0;
+      }
+    }else{
+      pC->pData = sqlite3_malloc( pC->nData+2 );
+      if( !pC->pData ) goto no_mem;
+      memcpy(pC->pData, pData->z, pC->nData);
+      pC->pData[pC->nData] = 0;
+      pC->pData[pC->nData+1] = 0;
+    }
+    pC->nullRow = 0;
+  }else{
+    int nZero;
+    if( pData->flags & MEM_Zero ){
+      nZero = pData->u.i;
+    }else{
+      nZero = 0;
+    }
+    rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
+                            pData->z, pData->n, nZero,
+                            pOp->p5 & OPFLAG_APPEND);
+  }
+  
+  pC->rowidIsValid = 0;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+
+  /* Invoke the update-hook if required. */
+  if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
+    const char *zDb = db->aDb[pC->iDb].zName;
+    const char *zTbl = pOp->p4.z;
+    int op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
+    assert( pC->isTable );
+    db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
+    assert( pC->iDb>=0 );
+  }
+  break;
+}
+
+/* Opcode: Delete P1 P2 * P4 *
+**
+** Delete the record at which the P1 cursor is currently pointing.
+**
+** The cursor will be left pointing at either the next or the previous
+** record in the table. If it is left pointing at the next record, then
+** the next Next instruction will be a no-op.  Hence it is OK to delete
+** a record from within an Next loop.
+**
+** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
+** incremented (otherwise not).
+**
+** P1 must not be pseudo-table.  It has to be a real table with
+** multiple rows.
+**
+** If P4 is not NULL, then it is the name of the table that P1 is
+** pointing to.  The update hook will be invoked, if it exists.
+** If P4 is not NULL then the P1 cursor must have been positioned
+** using OP_NotFound prior to invoking this opcode.
+*/
+case OP_Delete: {
+  int i = pOp->p1;
+  i64 iKey;
+  Cursor *pC;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */
+
+  /* If the update-hook will be invoked, set iKey to the rowid of the
+  ** row being deleted.
+  */
+  if( db->xUpdateCallback && pOp->p4.z ){
+    assert( pC->isTable );
+    assert( pC->rowidIsValid );  /* lastRowid set by previous OP_NotFound */
+    iKey = pC->lastRowid;
+  }
+
+  rc = sqlite3VdbeCursorMoveto(pC);
+  if( rc ) goto abort_due_to_error;
+  rc = sqlite3BtreeDelete(pC->pCursor);
+  pC->nextRowidValid = 0;
+  pC->cacheStatus = CACHE_STALE;
+
+  /* Invoke the update-hook if required. */
+  if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
+    const char *zDb = db->aDb[pC->iDb].zName;
+    const char *zTbl = pOp->p4.z;
+    db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, iKey);
+    assert( pC->iDb>=0 );
+  }
+  if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
+  break;
+}
+
+/* Opcode: ResetCount P1 * *
+**
+** This opcode resets the VMs internal change counter to 0. If P1 is true,
+** then the value of the change counter is copied to the database handle
+** change counter (returned by subsequent calls to sqlite3_changes())
+** before it is reset. This is used by trigger programs.
+*/
+case OP_ResetCount: {
+  if( pOp->p1 ){
+    sqlite3VdbeSetChanges(db, p->nChange);
+  }
+  p->nChange = 0;
+  break;
+}
+
+/* Opcode: RowData P1 P2 * * *
+**
+** Write into register P2 the complete row data for cursor P1.
+** There is no interpretation of the data.  
+** It is just copied onto the P2 register exactly as 
+** it is found in the database file.
+**
+** If the P1 cursor must be pointing to a valid row (not a NULL row)
+** of a real table, not a pseudo-table.
+*/
+/* Opcode: RowKey P1 P2 * * *
+**
+** Write into register P2 the complete row key for cursor P1.
+** There is no interpretation of the data.  
+** The key is copied onto the P3 register exactly as 
+** it is found in the database file.
+**
+** If the P1 cursor must be pointing to a valid row (not a NULL row)
+** of a real table, not a pseudo-table.
+*/
+case OP_RowKey:
+case OP_RowData: {
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  u32 n;
+
+  pOut = &p->aMem[pOp->p2];
+
+  /* Note that RowKey and RowData are really exactly the same instruction */
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC->isTable || pOp->opcode==OP_RowKey );
+  assert( pC->isIndex || pOp->opcode==OP_RowData );
+  assert( pC!=0 );
+  assert( pC->nullRow==0 );
+  assert( pC->pseudoTable==0 );
+  assert( pC->pCursor!=0 );
+  pCrsr = pC->pCursor;
+  rc = sqlite3VdbeCursorMoveto(pC);
+  if( rc ) goto abort_due_to_error;
+  if( pC->isIndex ){
+    i64 n64;
+    assert( !pC->isTable );
+    sqlite3BtreeKeySize(pCrsr, &n64);
+    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+    n = n64;
+  }else{
+    sqlite3BtreeDataSize(pCrsr, &n);
+    if( n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+  }
+  if( sqlite3VdbeMemGrow(pOut, n, 0) ){
+    goto no_mem;
+  }
+  pOut->n = n;
+  MemSetTypeFlag(pOut, MEM_Blob);
+  if( pC->isIndex ){
+    rc = sqlite3BtreeKey(pCrsr, 0, n, pOut->z);
+  }else{
+    rc = sqlite3BtreeData(pCrsr, 0, n, pOut->z);
+  }
+  pOut->enc = SQLITE_UTF8;  /* In case the blob is ever cast to text */
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Rowid P1 P2 * * *
+**
+** Store in register P2 an integer which is the key of the table entry that
+** P1 is currently point to.  If p2==0 then push the integer.
+*/
+case OP_Rowid: {                 /* out2-prerelease */
+  int i = pOp->p1;
+  Cursor *pC;
+  i64 v;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  rc = sqlite3VdbeCursorMoveto(pC);
+  if( rc ) goto abort_due_to_error;
+  if( pC->rowidIsValid ){
+    v = pC->lastRowid;
+  }else if( pC->pseudoTable ){
+    v = keyToInt(pC->iKey);
+  }else if( pC->nullRow ){
+    /* Leave the rowid set to a NULL */
+    break;
+  }else{
+    assert( pC->pCursor!=0 );
+    sqlite3BtreeKeySize(pC->pCursor, &v);
+    v = keyToInt(v);
+  }
+  pOut->u.i = v;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+/* Opcode: NullRow P1 * * * *
+**
+** Move the cursor P1 to a null row.  Any OP_Column operations
+** that occur while the cursor is on the null row will always
+** write a NULL.
+*/
+case OP_NullRow: {
+  int i = pOp->p1;
+  Cursor *pC;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  pC->nullRow = 1;
+  pC->rowidIsValid = 0;
+  break;
+}
+
+/* Opcode: Last P1 P2 * * *
+**
+** The next use of the Rowid or Column or Next instruction for P1 
+** will refer to the last entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+*/
+case OP_Last: {        /* jump */
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  pCrsr = pC->pCursor;
+  assert( pCrsr!=0 );
+  rc = sqlite3BtreeLast(pCrsr, &res);
+  pC->nullRow = res;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( res && pOp->p2>0 ){
+    pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+
+/* Opcode: Sort P1 P2 * * *
+**
+** This opcode does exactly the same thing as OP_Rewind except that
+** it increments an undocumented global variable used for testing.
+**
+** Sorting is accomplished by writing records into a sorting index,
+** then rewinding that index and playing it back from beginning to
+** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
+** rewinding so that the global variable will be incremented and
+** regression tests can determine whether or not the optimizer is
+** correctly optimizing out sorts.
+*/
+case OP_Sort: {        /* jump */
+#ifdef SQLITE_TEST
+  sqlite3_sort_count++;
+  sqlite3_search_count--;
+#endif
+  /* Fall through into OP_Rewind */
+}
+/* Opcode: Rewind P1 P2 * * *
+**
+** The next use of the Rowid or Column or Next instruction for P1 
+** will refer to the first entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+*/
+case OP_Rewind: {        /* jump */
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( i>=0 && i<p->nCursor );
+  pC = p->apCsr[i];
+  assert( pC!=0 );
+  if( (pCrsr = pC->pCursor)!=0 ){
+    rc = sqlite3BtreeFirst(pCrsr, &res);
+    pC->atFirst = res==0;
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }else{
+    res = 1;
+  }
+  pC->nullRow = res;
+  assert( pOp->p2>0 && pOp->p2<p->nOp );
+  if( res ){
+    pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: Next P1 P2 * * *
+**
+** Advance cursor P1 so that it points to the next key/data pair in its
+** table or index.  If there are no more key/value pairs then fall through
+** to the following instruction.  But if the cursor advance was successful,
+** jump immediately to P2.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.
+**
+** See also: Prev
+*/
+/* Opcode: Prev P1 P2 * * *
+**
+** Back up cursor P1 so that it points to the previous key/data pair in its
+** table or index.  If there is no previous key/value pairs then fall through
+** to the following instruction.  But if the cursor backup was successful,
+** jump immediately to P2.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.
+*/
+case OP_Prev:          /* jump */
+case OP_Next: {        /* jump */
+  Cursor *pC;
+  BtCursor *pCrsr;
+
+  CHECK_FOR_INTERRUPT;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC==0 ){
+    break;  /* See ticket #2273 */
+  }
+  pCrsr = pC->pCursor;
+  assert( pCrsr );
+  if( pC->nullRow==0 ){
+    int res = 1;
+    assert( pC->deferredMoveto==0 );
+    rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
+                                sqlite3BtreePrevious(pCrsr, &res);
+    pC->nullRow = res;
+    pC->cacheStatus = CACHE_STALE;
+    if( res==0 ){
+      pc = pOp->p2 - 1;
+#ifdef SQLITE_TEST
+      sqlite3_search_count++;
+#endif
+    }
+  }
+  pC->rowidIsValid = 0;
+  break;
+}
+
+/* Opcode: IdxInsert P1 P2 P3 * *
+**
+** Register P2 holds a SQL index key made using the
+** MakeIdxRec instructions.  This opcode writes that key
+** into the index P1.  Data for the entry is nil.
+**
+** P3 is a flag that provides a hint to the b-tree layer that this
+** insert is likely to be an append.
+**
+** This instruction only works for indices.  The equivalent instruction
+** for tables is OP_Insert.
+*/
+case OP_IdxInsert: {        /* in2 */
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  assert( pIn2->flags & MEM_Blob );
+  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+    assert( pC->isTable==0 );
+    rc = ExpandBlob(pIn2);
+    if( rc==SQLITE_OK ){
+      int nKey = pIn2->n;
+      const char *zKey = pIn2->z;
+      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3);
+      assert( pC->deferredMoveto==0 );
+      pC->cacheStatus = CACHE_STALE;
+    }
+  }
+  break;
+}
+
+/* Opcode: IdxDeleteM P1 P2 P3 * *
+**
+** The content of P3 registers starting at register P2 form
+** an unpacked index key. This opcode removes that entry from the 
+** index opened by cursor P1.
+*/
+case OP_IdxDelete: {
+  int i = pOp->p1;
+  Cursor *pC;
+  BtCursor *pCrsr;
+  assert( pOp->p3>0 );
+  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem );
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+    int res;
+    UnpackedRecord r;
+    r.pKeyInfo = pC->pKeyInfo;
+    r.nField = pOp->p3;
+    r.needFree = 0;
+    r.needDestroy = 0;
+    r.aMem = &p->aMem[pOp->p2];
+    rc = sqlite3BtreeMoveto(pCrsr, 0, &r, 0, 0, &res);
+    if( rc==SQLITE_OK && res==0 ){
+      rc = sqlite3BtreeDelete(pCrsr);
+    }
+    assert( pC->deferredMoveto==0 );
+    pC->cacheStatus = CACHE_STALE;
+  }
+  break;
+}
+
+/* Opcode: IdxRowid P1 P2 * * *
+**
+** Write into register P2 an integer which is the last entry in the record at
+** the end of the index key pointed to by cursor P1.  This integer should be
+** the rowid of the table entry to which this index entry points.
+**
+** See also: Rowid, MakeIdxRec.
+*/
+case OP_IdxRowid: {              /* out2-prerelease */
+  int i = pOp->p1;
+  BtCursor *pCrsr;
+  Cursor *pC;
+
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+    i64 rowid;
+
+    assert( pC->deferredMoveto==0 );
+    assert( pC->isTable==0 );
+    if( !pC->nullRow ){
+      rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
+      if( rc!=SQLITE_OK ){
+        goto abort_due_to_error;
+      }
+      MemSetTypeFlag(pOut, MEM_Int);
+      pOut->u.i = rowid;
+    }
+  }
+  break;
+}
+
+/* Opcode: IdxGE P1 P2 P3 P4 P5
+**
+** The P4 register values beginning with P3 form an unpacked index 
+** key that omits the ROWID.  Compare this key value against the index 
+** that P1 is currently pointing to, ignoring the ROWID on the P1 index.
+**
+** If the P1 index entry is greater than or equal to the key value
+** then jump to P2.  Otherwise fall through to the next instruction.
+**
+** If P5 is non-zero then the key value is increased by an epsilon 
+** prior to the comparison.  This make the opcode work like IdxGT except
+** that if the key from register P3 is a prefix of the key in the cursor,
+** the result is false whereas it would be true with IdxGT.
+*/
+/* Opcode: IdxLT P1 P2 P3 * P5
+**
+** The P4 register values beginning with P3 form an unpacked index 
+** key that omits the ROWID.  Compare this key value against the index 
+** that P1 is currently pointing to, ignoring the ROWID on the P1 index.
+**
+** If the P1 index entry is less than the key value then jump to P2.
+** Otherwise fall through to the next instruction.
+**
+** If P5 is non-zero then the key value is increased by an epsilon prior 
+** to the comparison.  This makes the opcode work like IdxLE.
+*/
+case OP_IdxLT:          /* jump, in3 */
+case OP_IdxGE: {        /* jump, in3 */
+  int i= pOp->p1;
+  Cursor *pC;
+
+  assert( i>=0 && i<p->nCursor );
+  assert( p->apCsr[i]!=0 );
+  if( (pC = p->apCsr[i])->pCursor!=0 ){
+    int res;
+    UnpackedRecord r;
+    assert( pC->deferredMoveto==0 );
+    assert( pOp->p5==0 || pOp->p5==1 );
+    assert( pOp->p4type==P4_INT32 );
+    r.pKeyInfo = pC->pKeyInfo;
+    r.nField = pOp->p4.i;
+    r.needFree = 0;
+    r.needDestroy = 0;
+    r.aMem = &p->aMem[pOp->p3];
+    *pC->pIncrKey = pOp->p5;
+    rc = sqlite3VdbeIdxKeyCompare(pC, &r, 0, 0, &res);
+    *pC->pIncrKey = 0;
+    if( pOp->opcode==OP_IdxLT ){
+      res = -res;
+    }else{
+      assert( pOp->opcode==OP_IdxGE );
+      res++;
+    }
+    if( res>0 ){
+      pc = pOp->p2 - 1 ;
+    }
+  }
+  break;
+}
+
+/* Opcode: Destroy P1 P2 P3 * *
+**
+** Delete an entire database table or index whose root page in the database
+** file is given by P1.
+**
+** The table being destroyed is in the main database file if P3==0.  If
+** P3==1 then the table to be clear is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If AUTOVACUUM is enabled then it is possible that another root page
+** might be moved into the newly deleted root page in order to keep all
+** root pages contiguous at the beginning of the database.  The former
+** value of the root page that moved - its value before the move occurred -
+** is stored in register P2.  If no page 
+** movement was required (because the table being dropped was already 
+** the last one in the database) then a zero is stored in register P2.
+** If AUTOVACUUM is disabled then a zero is stored in register P2.
+**
+** See also: Clear
+*/
+case OP_Destroy: {     /* out2-prerelease */
+  int iMoved;
+  int iCnt;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Vdbe *pVdbe;
+  iCnt = 0;
+  for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
+    if( pVdbe->magic==VDBE_MAGIC_RUN && pVdbe->inVtabMethod<2 && pVdbe->pc>=0 ){
+      iCnt++;
+    }
+  }
+#else
+  iCnt = db->activeVdbeCnt;
+#endif
+  if( iCnt>1 ){
+    rc = SQLITE_LOCKED;
+    p->errorAction = OE_Abort;
+  }else{
+    int iDb = pOp->p3;
+    assert( iCnt==1 );
+    assert( (p->btreeMask & (1<<iDb))!=0 );
+    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
+    MemSetTypeFlag(pOut, MEM_Int);
+    pOut->u.i = iMoved;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( rc==SQLITE_OK && iMoved!=0 ){
+      sqlite3RootPageMoved(&db->aDb[iDb], iMoved, pOp->p1);
+    }
+#endif
+  }
+  break;
+}
+
+/* Opcode: Clear P1 P2 *
+**
+** Delete all contents of the database table or index whose root page
+** in the database file is given by P1.  But, unlike Destroy, do not
+** remove the table or index from the database file.
+**
+** The table being clear is in the main database file if P2==0.  If
+** P2==1 then the table to be clear is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** See also: Destroy
+*/
+case OP_Clear: {
+  assert( (p->btreeMask & (1<<pOp->p2))!=0 );
+  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, pOp->p1);
+  break;
+}
+
+/* Opcode: CreateTable P1 P2 * * *
+**
+** Allocate a new table in the main database file if P1==0 or in the
+** auxiliary database file if P1==1 or in an attached database if
+** P1>1.  Write the root page number of the new table into
+** register P2
+**
+** The difference between a table and an index is this:  A table must
+** have a 4-byte integer key and can have arbitrary data.  An index
+** has an arbitrary key but no data.
+**
+** See also: CreateIndex
+*/
+/* Opcode: CreateIndex P1 P2 * * *
+**
+** Allocate a new index in the main database file if P1==0 or in the
+** auxiliary database file if P1==1 or in an attached database if
+** P1>1.  Write the root page number of the new table into
+** register P2.
+**
+** See documentation on OP_CreateTable for additional information.
+*/
+case OP_CreateIndex:            /* out2-prerelease */
+case OP_CreateTable: {          /* out2-prerelease */
+  int pgno;
+  int flags;
+  Db *pDb;
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  if( pOp->opcode==OP_CreateTable ){
+    /* flags = BTREE_INTKEY; */
+    flags = BTREE_LEAFDATA|BTREE_INTKEY;
+  }else{
+    flags = BTREE_ZERODATA;
+  }
+  rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, flags);
+  if( rc==SQLITE_OK ){
+    pOut->u.i = pgno;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }
+  break;
+}
+
+/* Opcode: ParseSchema P1 P2 * P4 *
+**
+** Read and parse all entries from the SQLITE_MASTER table of database P1
+** that match the WHERE clause P4.  P2 is the "force" flag.   Always do
+** the parsing if P2 is true.  If P2 is false, then this routine is a
+** no-op if the schema is not currently loaded.  In other words, if P2
+** is false, the SQLITE_MASTER table is only parsed if the rest of the
+** schema is already loaded into the symbol table.
+**
+** This opcode invokes the parser to create a new virtual machine,
+** then runs the new virtual machine.  It is thus a reentrant opcode.
+*/
+case OP_ParseSchema: {
+  char *zSql;
+  int iDb = pOp->p1;
+  const char *zMaster;
+  InitData initData;
+
+  assert( iDb>=0 && iDb<db->nDb );
+  if( !pOp->p2 && !DbHasProperty(db, iDb, DB_SchemaLoaded) ){
+    break;
+  }
+  zMaster = SCHEMA_TABLE(iDb);
+  initData.db = db;
+  initData.iDb = pOp->p1;
+  initData.pzErrMsg = &p->zErrMsg;
+  zSql = sqlite3MPrintf(db,
+     "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
+     db->aDb[iDb].zName, zMaster, pOp->p4.z);
+  if( zSql==0 ) goto no_mem;
+  (void)sqlite3SafetyOff(db);
+  assert( db->init.busy==0 );
+  db->init.busy = 1;
+  assert( !db->mallocFailed );
+  rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+  if( rc==SQLITE_ABORT ) rc = initData.rc;
+  sqlite3_free(zSql);
+  db->init.busy = 0;
+  (void)sqlite3SafetyOn(db);
+  if( rc==SQLITE_NOMEM ){
+    goto no_mem;
+  }
+  break;  
+}
+
+#if !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)
+/* Opcode: LoadAnalysis P1 * * * *
+**
+** Read the sqlite_stat1 table for database P1 and load the content
+** of that table into the internal index hash table.  This will cause
+** the analysis to be used when preparing all subsequent queries.
+*/
+case OP_LoadAnalysis: {
+  int iDb = pOp->p1;
+  assert( iDb>=0 && iDb<db->nDb );
+  rc = sqlite3AnalysisLoad(db, iDb);
+  break;  
+}
+#endif /* !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)  */
+
+/* Opcode: DropTable P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the table named P4 in database P1.  This is called after a table
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTable: {
+  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropIndex P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the index named P4 in database P1.  This is called after an index
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropIndex: {
+  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropTrigger P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the trigger named P4 in database P1.  This is called after a trigger
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTrigger: {
+  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/* Opcode: IntegrityCk P1 P2 P3 * P5
+**
+** Do an analysis of the currently open database.  Store in
+** register P1 the text of an error message describing any problems.
+** If no problems are found, store a NULL in register P1.
+**
+** The register P3 contains the maximum number of allowed errors.
+** At most reg(P3) errors will be reported.
+** In other words, the analysis stops as soon as reg(P1) errors are 
+** seen.  Reg(P1) is updated with the number of errors remaining.
+**
+** The root page numbers of all tables in the database are integer
+** stored in reg(P1), reg(P1+1), reg(P1+2), ....  There are P2 tables
+** total.
+**
+** If P5 is not zero, the check is done on the auxiliary database
+** file, not the main database file.
+**
+** This opcode is used to implement the integrity_check pragma.
+*/
+case OP_IntegrityCk: {
+  int nRoot;      /* Number of tables to check.  (Number of root pages.) */
+  int *aRoot;     /* Array of rootpage numbers for tables to be checked */
+  int j;          /* Loop counter */
+  int nErr;       /* Number of errors reported */
+  char *z;        /* Text of the error report */
+  Mem *pnErr;     /* Register keeping track of errors remaining */
+  
+  nRoot = pOp->p2;
+  assert( nRoot>0 );
+  aRoot = sqlite3_malloc( sizeof(int)*(nRoot+1) );
+  if( aRoot==0 ) goto no_mem;
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pnErr = &p->aMem[pOp->p3];
+  assert( (pnErr->flags & MEM_Int)!=0 );
+  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
+  pIn1 = &p->aMem[pOp->p1];
+  for(j=0; j<nRoot; j++){
+    aRoot[j] = sqlite3VdbeIntValue(&pIn1[j]);
+  }
+  aRoot[j] = 0;
+  assert( pOp->p5<db->nDb );
+  assert( (p->btreeMask & (1<<pOp->p5))!=0 );
+  z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, aRoot, nRoot,
+                                 pnErr->u.i, &nErr);
+  pnErr->u.i -= nErr;
+  sqlite3VdbeMemSetNull(pIn1);
+  if( nErr==0 ){
+    assert( z==0 );
+  }else{
+    sqlite3VdbeMemSetStr(pIn1, z, -1, SQLITE_UTF8, sqlite3_free);
+  }
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  sqlite3VdbeChangeEncoding(pIn1, encoding);
+  sqlite3_free(aRoot);
+  break;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/* Opcode: FifoWrite P1 * * * *
+**
+** Write the integer from register P1 into the Fifo.
+*/
+case OP_FifoWrite: {        /* in1 */
+  if( sqlite3VdbeFifoPush(&p->sFifo, sqlite3VdbeIntValue(pIn1))==SQLITE_NOMEM ){
+    goto no_mem;
+  }
+  break;
+}
+
+/* Opcode: FifoRead P1 P2 * * *
+**
+** Attempt to read a single integer from the Fifo.  Store that
+** integer in register P1.
+** 
+** If the Fifo is empty jump to P2.
+*/
+case OP_FifoRead: {         /* jump */
+  CHECK_FOR_INTERRUPT;
+  assert( pOp->p1>0 && pOp->p1<=p->nMem );
+  pOut = &p->aMem[pOp->p1];
+  MemSetTypeFlag(pOut, MEM_Int);
+  if( sqlite3VdbeFifoPop(&p->sFifo, &pOut->u.i)==SQLITE_DONE ){
+    pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+#ifndef SQLITE_OMIT_TRIGGER
+/* Opcode: ContextPush * * * 
+**
+** Save the current Vdbe context such that it can be restored by a ContextPop
+** opcode. The context stores the last insert row id, the last statement change
+** count, and the current statement change count.
+*/
+case OP_ContextPush: {
+  int i = p->contextStackTop++;
+  Context *pContext;
+
+  assert( i>=0 );
+  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
+  if( i>=p->contextStackDepth ){
+    p->contextStackDepth = i+1;
+    p->contextStack = sqlite3DbReallocOrFree(db, p->contextStack,
+                                          sizeof(Context)*(i+1));
+    if( p->contextStack==0 ) goto no_mem;
+  }
+  pContext = &p->contextStack[i];
+  pContext->lastRowid = db->lastRowid;
+  pContext->nChange = p->nChange;
+  pContext->sFifo = p->sFifo;
+  sqlite3VdbeFifoInit(&p->sFifo);
+  break;
+}
+
+/* Opcode: ContextPop * * * 
+**
+** Restore the Vdbe context to the state it was in when contextPush was last
+** executed. The context stores the last insert row id, the last statement
+** change count, and the current statement change count.
+*/
+case OP_ContextPop: {
+  Context *pContext = &p->contextStack[--p->contextStackTop];
+  assert( p->contextStackTop>=0 );
+  db->lastRowid = pContext->lastRowid;
+  p->nChange = pContext->nChange;
+  sqlite3VdbeFifoClear(&p->sFifo);
+  p->sFifo = pContext->sFifo;
+  break;
+}
+#endif /* #ifndef SQLITE_OMIT_TRIGGER */
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/* Opcode: MemMax P1 P2 * * *
+**
+** Set the value of register P1 to the maximum of its current value
+** and the value in register P2.
+**
+** This instruction throws an error if the memory cell is not initially
+** an integer.
+*/
+case OP_MemMax: {        /* in1, in2 */
+  sqlite3VdbeMemIntegerify(pIn1);
+  sqlite3VdbeMemIntegerify(pIn2);
+  if( pIn1->u.i<pIn2->u.i){
+    pIn1->u.i = pIn2->u.i;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+/* Opcode: IfPos P1 P2 * * *
+**
+** If the value of register P1 is 1 or greater, jump to P2.
+**
+** It is illegal to use this instruction on a register that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfPos: {        /* jump, in1 */
+  assert( pIn1->flags&MEM_Int );
+  if( pIn1->u.i>0 ){
+     pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: IfNeg P1 P2 * * *
+**
+** If the value of register P1 is less than zero, jump to P2. 
+**
+** It is illegal to use this instruction on a register that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfNeg: {        /* jump, in1 */
+  assert( pIn1->flags&MEM_Int );
+  if( pIn1->u.i<0 ){
+     pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: IfZero P1 P2 * * *
+**
+** If the value of register P1 is exactly 0, jump to P2. 
+**
+** It is illegal to use this instruction on a register that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfZero: {        /* jump, in1 */
+  assert( pIn1->flags&MEM_Int );
+  if( pIn1->u.i==0 ){
+     pc = pOp->p2 - 1;
+  }
+  break;
+}
+
+/* Opcode: AggStep * P2 P3 P4 P5
+**
+** Execute the step function for an aggregate.  The
+** function has P5 arguments.   P4 is a pointer to the FuncDef
+** structure that specifies the function.  Use register
+** P3 as the accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+*/
+case OP_AggStep: {
+  int n = pOp->p5;
+  int i;
+  Mem *pMem, *pRec;
+  sqlite3_context ctx;
+  sqlite3_value **apVal;
+
+  assert( n>=0 );
+  pRec = &p->aMem[pOp->p2];
+  apVal = p->apArg;
+  assert( apVal || n==0 );
+  for(i=0; i<n; i++, pRec++){
+    apVal[i] = pRec;
+    storeTypeInfo(pRec, encoding);
+  }
+  ctx.pFunc = pOp->p4.pFunc;
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  ctx.pMem = pMem = &p->aMem[pOp->p3];
+  pMem->n++;
+  ctx.s.flags = MEM_Null;
+  ctx.s.z = 0;
+  ctx.s.zMalloc = 0;
+  ctx.s.xDel = 0;
+  ctx.s.db = db;
+  ctx.isError = 0;
+  ctx.pColl = 0;
+  if( ctx.pFunc->needCollSeq ){
+    assert( pOp>p->aOp );
+    assert( pOp[-1].p4type==P4_COLLSEQ );
+    assert( pOp[-1].opcode==OP_CollSeq );
+    ctx.pColl = pOp[-1].p4.pColl;
+  }
+  (ctx.pFunc->xStep)(&ctx, n, apVal);
+  if( ctx.isError ){
+    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
+    rc = ctx.isError;
+  }
+  sqlite3VdbeMemRelease(&ctx.s);
+  break;
+}
+
+/* Opcode: AggFinal P1 P2 * P4 *
+**
+** Execute the finalizer function for an aggregate.  P1 is
+** the memory location that is the accumulator for the aggregate.
+**
+** P2 is the number of arguments that the step function takes and
+** P4 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P4 argument is only needed for the degenerate case where
+** the step function was not previously called.
+*/
+case OP_AggFinal: {
+  Mem *pMem;
+  assert( pOp->p1>0 && pOp->p1<=p->nMem );
+  pMem = &p->aMem[pOp->p1];
+  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+  rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
+  if( rc==SQLITE_ERROR ){
+    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(pMem), (char*)0);
+  }
+  sqlite3VdbeChangeEncoding(pMem, encoding);
+  UPDATE_MAX_BLOBSIZE(pMem);
+  if( sqlite3VdbeMemTooBig(pMem) ){
+    goto too_big;
+  }
+  break;
+}
+
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/* Opcode: Vacuum * * * * *
+**
+** Vacuum the entire database.  This opcode will cause other virtual
+** machines to be created and run.  It may not be called from within
+** a transaction.
+*/
+case OP_Vacuum: {
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse; 
+  rc = sqlite3RunVacuum(&p->zErrMsg, db);
+  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+  break;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+/* Opcode: IncrVacuum P1 P2 * * *
+**
+** Perform a single step of the incremental vacuum procedure on
+** the P1 database. If the vacuum has finished, jump to instruction
+** P2. Otherwise, fall through to the next instruction.
+*/
+case OP_IncrVacuum: {        /* jump */
+  Btree *pBt;
+
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+  pBt = db->aDb[pOp->p1].pBt;
+  rc = sqlite3BtreeIncrVacuum(pBt);
+  if( rc==SQLITE_DONE ){
+    pc = pOp->p2 - 1;
+    rc = SQLITE_OK;
+  }
+  break;
+}
+#endif
+
+/* Opcode: Expire P1 * * * *
+**
+** Cause precompiled statements to become expired. An expired statement
+** fails with an error code of SQLITE_SCHEMA if it is ever executed 
+** (via sqlite3_step()).
+** 
+** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
+** then only the currently executing statement is affected. 
+*/
+case OP_Expire: {
+  if( !pOp->p1 ){
+    sqlite3ExpirePreparedStatements(db);
+  }else{
+    p->expired = 1;
+  }
+  break;
+}
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/* Opcode: TableLock P1 P2 P3 P4 *
+**
+** Obtain a lock on a particular table. This instruction is only used when
+** the shared-cache feature is enabled. 
+**
+** If P1 is  the index of the database in sqlite3.aDb[] of the database
+** on which the lock is acquired.  A readlock is obtained if P3==0 or
+** a write lock if P3==1.
+**
+** P2 contains the root-page of the table to lock.
+**
+** P4 contains a pointer to the name of the table being locked. This is only
+** used to generate an error message if the lock cannot be obtained.
+*/
+case OP_TableLock: {
+  int p1 = pOp->p1; 
+  u8 isWriteLock = pOp->p3;
+  assert( p1>=0 && p1<db->nDb );
+  assert( (p->btreeMask & (1<<p1))!=0 );
+  assert( isWriteLock==0 || isWriteLock==1 );
+  rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
+  if( rc==SQLITE_LOCKED ){
+    const char *z = pOp->p4.z;
+    sqlite3SetString(&p->zErrMsg, "database table is locked: ", z, (char*)0);
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VBegin * * * P4 *
+**
+** P4 a pointer to an sqlite3_vtab structure. Call the xBegin method 
+** for that table.
+*/
+case OP_VBegin: {
+  rc = sqlite3VtabBegin(db, pOp->p4.pVtab);
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCreate P1 * * P4 *
+**
+** P4 is the name of a virtual table in database P1. Call the xCreate method
+** for that table.
+*/
+case OP_VCreate: {
+  rc = sqlite3VtabCallCreate(db, pOp->p1, pOp->p4.z, &p->zErrMsg);
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VDestroy P1 * * P4 *
+**
+** P4 is the name of a virtual table in database P1.  Call the xDestroy method
+** of that table.
+*/
+case OP_VDestroy: {
+  p->inVtabMethod = 2;
+  rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p4.z);
+  p->inVtabMethod = 0;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VOpen P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** P1 is a cursor number.  This opcode opens a cursor to the virtual
+** table and stores that cursor in P1.
+*/
+case OP_VOpen: {
+  Cursor *pCur = 0;
+  sqlite3_vtab_cursor *pVtabCursor = 0;
+
+  sqlite3_vtab *pVtab = pOp->p4.pVtab;
+  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
+
+  assert(pVtab && pModule);
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  rc = pModule->xOpen(pVtab, &pVtabCursor);
+  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+  if( SQLITE_OK==rc ){
+    /* Initialise sqlite3_vtab_cursor base class */
+    pVtabCursor->pVtab = pVtab;
+
+    /* Initialise vdbe cursor object */
+    pCur = allocateCursor(p, pOp->p1, &pOp[-1], -1, 0);
+    if( pCur ){
+      pCur->pVtabCursor = pVtabCursor;
+      pCur->pModule = pVtabCursor->pVtab->pModule;
+    }else{
+      db->mallocFailed = 1;
+      pModule->xClose(pVtabCursor);
+    }
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VFilter P1 P2 P3 P4 *
+**
+** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
+** the filtered result set is empty.
+**
+** P4 is either NULL or a string that was generated by the xBestIndex
+** method of the module.  The interpretation of the P4 string is left
+** to the module implementation.
+**
+** This opcode invokes the xFilter method on the virtual table specified
+** by P1.  The integer query plan parameter to xFilter is stored in register
+** P3. Register P3+1 stores the argc parameter to be passed to the
+** xFilter method. Registers P3+2..P3+1+argc are the argc additional
+** parametersneath additional parameters which are passed to
+** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
+**
+** A jump is made to P2 if the result set after filtering would be empty.
+*/
+case OP_VFilter: {   /* jump */
+  int nArg;
+  int iQuery;
+  const sqlite3_module *pModule;
+  Mem *pQuery = &p->aMem[pOp->p3];
+  Mem *pArgc = &pQuery[1];
+
+  Cursor *pCur = p->apCsr[pOp->p1];
+
+  REGISTER_TRACE(pOp->p3, pQuery);
+  assert( pCur->pVtabCursor );
+  pModule = pCur->pVtabCursor->pVtab->pModule;
+
+  /* Grab the index number and argc parameters */
+  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
+  nArg = pArgc->u.i;
+  iQuery = pQuery->u.i;
+
+  /* Invoke the xFilter method */
+  {
+    int res = 0;
+    int i;
+    Mem **apArg = p->apArg;
+    for(i = 0; i<nArg; i++){
+      apArg[i] = &pArgc[i+1];
+      storeTypeInfo(apArg[i], 0);
+    }
+
+    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+    p->inVtabMethod = 1;
+    rc = pModule->xFilter(pCur->pVtabCursor, iQuery, pOp->p4.z, nArg, apArg);
+    p->inVtabMethod = 0;
+    if( rc==SQLITE_OK ){
+      res = pModule->xEof(pCur->pVtabCursor);
+    }
+    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+
+    if( res ){
+      pc = pOp->p2 - 1;
+    }
+  }
+  pCur->nullRow = 0;
+
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRowid P1 P2 * * *
+**
+** Store into register P2  the rowid of
+** the virtual-table that the P1 cursor is pointing to.
+*/
+case OP_VRowid: {             /* out2-prerelease */
+  const sqlite3_module *pModule;
+  sqlite_int64 iRow;
+  Cursor *pCur = p->apCsr[pOp->p1];
+
+  assert( pCur->pVtabCursor );
+  if( pCur->nullRow ){
+    break;
+  }
+  pModule = pCur->pVtabCursor->pVtab->pModule;
+  assert( pModule->xRowid );
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  rc = pModule->xRowid(pCur->pVtabCursor, &iRow);
+  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+  MemSetTypeFlag(pOut, MEM_Int);
+  pOut->u.i = iRow;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VColumn P1 P2 P3 * *
+**
+** Store the value of the P2-th column of
+** the row of the virtual-table that the 
+** P1 cursor is pointing to into register P3.
+*/
+case OP_VColumn: {
+  const sqlite3_module *pModule;
+  Mem *pDest;
+  sqlite3_context sContext;
+
+  Cursor *pCur = p->apCsr[pOp->p1];
+  assert( pCur->pVtabCursor );
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pDest = &p->aMem[pOp->p3];
+  if( pCur->nullRow ){
+    sqlite3VdbeMemSetNull(pDest);
+    break;
+  }
+  pModule = pCur->pVtabCursor->pVtab->pModule;
+  assert( pModule->xColumn );
+  memset(&sContext, 0, sizeof(sContext));
+
+  /* The output cell may already have a buffer allocated. Move
+  ** the current contents to sContext.s so in case the user-function 
+  ** can use the already allocated buffer instead of allocating a 
+  ** new one.
+  */
+  sqlite3VdbeMemMove(&sContext.s, pDest);
+  MemSetTypeFlag(&sContext.s, MEM_Null);
+
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);
+
+  /* Copy the result of the function to the P3 register. We
+  ** do this regardless of whether or not an error occured to ensure any
+  ** dynamic allocation in sContext.s (a Mem struct) is  released.
+  */
+  sqlite3VdbeChangeEncoding(&sContext.s, encoding);
+  REGISTER_TRACE(pOp->p3, pDest);
+  sqlite3VdbeMemMove(pDest, &sContext.s);
+  UPDATE_MAX_BLOBSIZE(pDest);
+
+  if( sqlite3SafetyOn(db) ){
+    goto abort_due_to_misuse;
+  }
+  if( sqlite3VdbeMemTooBig(pDest) ){
+    goto too_big;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VNext P1 P2 * * *
+**
+** Advance virtual table P1 to the next row in its result set and
+** jump to instruction P2.  Or, if the virtual table has reached
+** the end of its result set, then fall through to the next instruction.
+*/
+case OP_VNext: {   /* jump */
+  const sqlite3_module *pModule;
+  int res = 0;
+
+  Cursor *pCur = p->apCsr[pOp->p1];
+  assert( pCur->pVtabCursor );
+  if( pCur->nullRow ){
+    break;
+  }
+  pModule = pCur->pVtabCursor->pVtab->pModule;
+  assert( pModule->xNext );
+
+  /* Invoke the xNext() method of the module. There is no way for the
+  ** underlying implementation to return an error if one occurs during
+  ** xNext(). Instead, if an error occurs, true is returned (indicating that 
+  ** data is available) and the error code returned when xColumn or
+  ** some other method is next invoked on the save virtual table cursor.
+  */
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  p->inVtabMethod = 1;
+  rc = pModule->xNext(pCur->pVtabCursor);
+  p->inVtabMethod = 0;
+  if( rc==SQLITE_OK ){
+    res = pModule->xEof(pCur->pVtabCursor);
+  }
+  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+
+  if( !res ){
+    /* If there is data, jump to P2 */
+    pc = pOp->p2 - 1;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRename P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xRename method. The value
+** in register P1 is passed as the zName argument to the xRename method.
+*/
+case OP_VRename: {
+  sqlite3_vtab *pVtab = pOp->p4.pVtab;
+  Mem *pName = &p->aMem[pOp->p1];
+  assert( pVtab->pModule->xRename );
+  REGISTER_TRACE(pOp->p1, pName);
+
+  Stringify(pName, encoding);
+
+  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+  sqlite3VtabLock(pVtab);
+  rc = pVtab->pModule->xRename(pVtab, pName->z);
+  sqlite3VtabUnlock(db, pVtab);
+  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+
+  break;
+}
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VUpdate P1 P2 P3 P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xUpdate method. P2 values
+** are contiguous memory cells starting at P3 to pass to the xUpdate 
+** invocation. The value in register (P3+P2-1) corresponds to the 
+** p2th element of the argv array passed to xUpdate.
+**
+** The xUpdate method will do a DELETE or an INSERT or both.
+** The argv[0] element (which corresponds to memory cell P3)
+** is the rowid of a row to delete.  If argv[0] is NULL then no 
+** deletion occurs.  The argv[1] element is the rowid of the new 
+** row.  This can be NULL to have the virtual table select the new 
+** rowid for itself.  The subsequent elements in the array are 
+** the values of columns in the new row.
+**
+** If P2==1 then no insert is performed.  argv[0] is the rowid of
+** a row to delete.
+**
+** P1 is a boolean flag. If it is set to true and the xUpdate call
+** is successful, then the value returned by sqlite3_last_insert_rowid() 
+** is set to the value of the rowid for the row just inserted.
+*/
+case OP_VUpdate: {
+  sqlite3_vtab *pVtab = pOp->p4.pVtab;
+  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
+  int nArg = pOp->p2;
+  assert( pOp->p4type==P4_VTAB );
+  if( pModule->xUpdate==0 ){
+    sqlite3SetString(&p->zErrMsg, "read-only table", 0);
+    rc = SQLITE_ERROR;
+  }else{
+    int i;
+    sqlite_int64 rowid;
+    Mem **apArg = p->apArg;
+    Mem *pX = &p->aMem[pOp->p3];
+    for(i=0; i<nArg; i++){
+      storeTypeInfo(pX, 0);
+      apArg[i] = pX;
+      pX++;
+    }
+    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+    sqlite3VtabLock(pVtab);
+    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
+    sqlite3VtabUnlock(db, pVtab);
+    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+    if( pOp->p1 && rc==SQLITE_OK ){
+      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
+      db->lastRowid = rowid;
+    }
+    p->nChange++;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_TRACE
+/* Opcode: Trace * * * P4 *
+**
+** If tracing is enabled (by the sqlite3_trace()) interface, then
+** the UTF-8 string contained in P4 is emitted on the trace callback.
+*/
+case OP_Trace: {
+  if( pOp->p4.z ){
+    if( db->xTrace ){
+      db->xTrace(db->pTraceArg, pOp->p4.z);
+    }
+#ifdef SQLITE_DEBUG
+    if( (db->flags & SQLITE_SqlTrace)!=0 ){
+      sqlite3DebugPrintf("SQL-trace: %s\n", pOp->p4.z);
+    }
+#endif /* SQLITE_DEBUG */
+  }
+  break;
+}
+#endif
+
+
+/* Opcode: Noop * * * * *
+**
+** Do nothing.  This instruction is often useful as a jump
+** destination.
+*/
+/*
+** The magic Explain opcode are only inserted when explain==2 (which
+** is to say when the EXPLAIN QUERY PLAN syntax is used.)
+** This opcode records information from the optimizer.  It is the
+** the same as a no-op.  This opcodesnever appears in a real VM program.
+*/
+default: {          /* This is really OP_Noop and OP_Explain */
+  break;
+}
+
+/*****************************************************************************
+** The cases of the switch statement above this line should all be indented
+** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
+** readability.  From this point on down, the normal indentation rules are
+** restored.
+*****************************************************************************/
+    }
+
+#ifdef VDBE_PROFILE
+    {
+      long long elapse = hwtime() - start;
+      pOp->cycles += elapse;
+      pOp->cnt++;
+#if 0
+        fprintf(stdout, "%10lld ", elapse);
+        sqlite3VdbePrintOp(stdout, origPc, &p->aOp[origPc]);
+#endif
+    }
+#endif
+
+    /* The following code adds nothing to the actual functionality
+    ** of the program.  It is only here for testing and debugging.
+    ** On the other hand, it does burn CPU cycles every time through
+    ** the evaluator loop.  So we can leave it out when NDEBUG is defined.
+    */
+#ifndef NDEBUG
+    assert( pc>=-1 && pc<p->nOp );
+
+#ifdef SQLITE_DEBUG
+    if( p->trace ){
+      if( rc!=0 ) fprintf(p->trace,"rc=%d\n",rc);
+      if( opProperty & OPFLG_OUT2_PRERELEASE ){
+        registerTrace(p->trace, pOp->p2, pOut);
+      }
+      if( opProperty & OPFLG_OUT3 ){
+        registerTrace(p->trace, pOp->p3, pOut);
+      }
+    }
+#endif  /* SQLITE_DEBUG */
+#endif  /* NDEBUG */
+  }  /* The end of the for(;;) loop the loops through opcodes */
+
+  /* If we reach this point, it means that execution is finished with
+  ** an error of some kind.
+  */
+vdbe_error_halt:
+  assert( rc );
+  p->rc = rc;
+  rc = SQLITE_ERROR;
+  sqlite3VdbeHalt(p);
+
+  /* This is the only way out of this procedure.  We have to
+  ** release the mutexes on btrees that were acquired at the
+  ** top. */
+vdbe_return:
+  sqlite3BtreeMutexArrayLeave(&p->aMutex);
+  return rc;
+
+  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
+  ** is encountered.
+  */
+too_big:
+  sqlite3SetString(&p->zErrMsg, "string or blob too big", (char*)0);
+  rc = SQLITE_TOOBIG;
+  goto vdbe_error_halt;
+
+  /* Jump to here if a malloc() fails.
+  */
+no_mem:
+  db->mallocFailed = 1;
+  sqlite3SetString(&p->zErrMsg, "out of memory", (char*)0);
+  rc = SQLITE_NOMEM;
+  goto vdbe_error_halt;
+
+  /* Jump to here for an SQLITE_MISUSE error.
+  */
+abort_due_to_misuse:
+  rc = SQLITE_MISUSE;
+  /* Fall thru into abort_due_to_error */
+
+  /* Jump to here for any other kind of fatal error.  The "rc" variable
+  ** should hold the error number.
+  */
+abort_due_to_error:
+  assert( p->zErrMsg==0 );
+  if( db->mallocFailed ) rc = SQLITE_NOMEM;
+  sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
+  goto vdbe_error_halt;
+
+  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
+  ** flag.
+  */
+abort_due_to_interrupt:
+  assert( db->u1.isInterrupted );
+  rc = SQLITE_INTERRUPT;
+  p->rc = rc;
+  sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
+  goto vdbe_error_halt;
+}
+
+/************** End of vdbe.c ************************************************/
+/************** Begin file vdbeblob.c ****************************************/
+/*
+** 2007 May 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to implement incremental BLOB I/O.
+**
+** $Id: vdbeblob.c,v 1.22 2008/04/24 09:49:55 danielk1977 Exp $
+*/
+
+
+#ifndef SQLITE_OMIT_INCRBLOB
+
+/*
+** Valid sqlite3_blob* handles point to Incrblob structures.
+*/
+typedef struct Incrblob Incrblob;
+struct Incrblob {
+  int flags;              /* Copy of "flags" passed to sqlite3_blob_open() */
+  int nByte;              /* Size of open blob, in bytes */
+  int iOffset;            /* Byte offset of blob in cursor data */
+  BtCursor *pCsr;         /* Cursor pointing at blob row */
+  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
+  sqlite3 *db;            /* The associated database */
+};
+
+/*
+** Open a blob handle.
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3* db,            /* The database connection */
+  const char *zDb,        /* The attached database containing the blob */
+  const char *zTable,     /* The table containing the blob */
+  const char *zColumn,    /* The column containing the blob */
+  sqlite_int64 iRow,      /* The row containing the glob */
+  int flags,              /* True -> read/write access, false -> read-only */
+  sqlite3_blob **ppBlob   /* Handle for accessing the blob returned here */
+){
+  int nAttempt = 0;
+  int iCol;               /* Index of zColumn in row-record */
+
+  /* This VDBE program seeks a btree cursor to the identified 
+  ** db/table/row entry. The reason for using a vdbe program instead
+  ** of writing code to use the b-tree layer directly is that the
+  ** vdbe program will take advantage of the various transaction,
+  ** locking and error handling infrastructure built into the vdbe.
+  **
+  ** After seeking the cursor, the vdbe executes an OP_ResultRow.
+  ** Code external to the Vdbe then "borrows" the b-tree cursor and
+  ** uses it to implement the blob_read(), blob_write() and 
+  ** blob_bytes() functions.
+  **
+  ** The sqlite3_blob_close() function finalizes the vdbe program,
+  ** which closes the b-tree cursor and (possibly) commits the 
+  ** transaction.
+  */
+  static const VdbeOpList openBlob[] = {
+    {OP_Transaction, 0, 0, 0},     /* 0: Start a transaction */
+    {OP_VerifyCookie, 0, 0, 0},    /* 1: Check the schema cookie */
+
+    /* One of the following two instructions is replaced by an
+    ** OP_Noop before exection.
+    */
+    {OP_SetNumColumns, 0, 0, 0},   /* 2: Num cols for cursor */
+    {OP_OpenRead, 0, 0, 0},        /* 3: Open cursor 0 for reading */
+    {OP_SetNumColumns, 0, 0, 0},   /* 4: Num cols for cursor */
+    {OP_OpenWrite, 0, 0, 0},       /* 5: Open cursor 0 for read/write */
+
+    {OP_Variable, 1, 1, 0},        /* 6: Push the rowid to the stack */
+    {OP_NotExists, 0, 10, 1},      /* 7: Seek the cursor */
+    {OP_Column, 0, 0, 1},          /* 8  */
+    {OP_ResultRow, 1, 0, 0},       /* 9  */
+    {OP_Close, 0, 0, 0},           /* 10  */
+    {OP_Halt, 0, 0, 0},            /* 11 */
+  };
+
+  Vdbe *v = 0;
+  int rc = SQLITE_OK;
+  char zErr[128];
+
+  zErr[0] = 0;
+  sqlite3_mutex_enter(db->mutex);
+  do {
+    Parse sParse;
+    Table *pTab;
+
+    memset(&sParse, 0, sizeof(Parse));
+    sParse.db = db;
+
+    rc = sqlite3SafetyOn(db);
+    if( rc!=SQLITE_OK ){
+      sqlite3_mutex_leave(db->mutex);
+      return rc;
+    }
+
+    sqlite3BtreeEnterAll(db);
+    pTab = sqlite3LocateTable(&sParse, 0, zTable, zDb);
+    if( pTab && IsVirtual(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open virtual table: %s", zTable);
+    }
+#ifndef SQLITE_OMIT_VIEW
+    if( pTab && pTab->pSelect ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
+    }
+#endif
+    if( !pTab ){
+      if( sParse.zErrMsg ){
+        sqlite3_snprintf(sizeof(zErr), zErr, "%s", sParse.zErrMsg);
+      }
+      sqlite3_free(sParse.zErrMsg);
+      rc = SQLITE_ERROR;
+      (void)sqlite3SafetyOff(db);
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+
+    /* Now search pTab for the exact column. */
+    for(iCol=0; iCol < pTab->nCol; iCol++) {
+      if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      sqlite3_snprintf(sizeof(zErr), zErr, "no such column: \"%s\"", zColumn);
+      rc = SQLITE_ERROR;
+      (void)sqlite3SafetyOff(db);
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+
+    /* If the value is being opened for writing, check that the
+    ** column is not indexed. It is against the rules to open an
+    ** indexed column for writing.
+    */
+    if( flags ){
+      Index *pIdx;
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        int j;
+        for(j=0; j<pIdx->nColumn; j++){
+          if( pIdx->aiColumn[j]==iCol ){
+            sqlite3_snprintf(sizeof(zErr), zErr,
+                             "cannot open indexed column for writing");
+            rc = SQLITE_ERROR;
+            (void)sqlite3SafetyOff(db);
+            sqlite3BtreeLeaveAll(db);
+            goto blob_open_out;
+          }
+        }
+      }
+    }
+
+    v = sqlite3VdbeCreate(db);
+    if( v ){
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
+
+      /* Configure the OP_Transaction */
+      sqlite3VdbeChangeP1(v, 0, iDb);
+      sqlite3VdbeChangeP2(v, 0, (flags ? 1 : 0));
+
+      /* Configure the OP_VerifyCookie */
+      sqlite3VdbeChangeP1(v, 1, iDb);
+      sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
+
+      /* Make sure a mutex is held on the table to be accessed */
+      sqlite3VdbeUsesBtree(v, iDb); 
+
+      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
+      ** parameter of the other to pTab->tnum. 
+      */
+      sqlite3VdbeChangeToNoop(v, (flags ? 3 : 5), 1);
+      sqlite3VdbeChangeP2(v, (flags ? 5 : 3), pTab->tnum);
+      sqlite3VdbeChangeP3(v, (flags ? 5 : 3), iDb);
+
+      /* Configure the OP_SetNumColumns. Configure the cursor to
+      ** think that the table has one more column than it really
+      ** does. An OP_Column to retrieve this imaginary column will
+      ** always return an SQL NULL. This is useful because it means
+      ** we can invoke OP_Column to fill in the vdbe cursors type 
+      ** and offset cache without causing any IO.
+      */
+      sqlite3VdbeChangeP2(v, flags ? 4 : 2, pTab->nCol+1);
+      if( !db->mallocFailed ){
+        sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
+      }
+    }
+   
+    sqlite3BtreeLeaveAll(db);
+    rc = sqlite3SafetyOff(db);
+    if( rc!=SQLITE_OK || db->mallocFailed ){
+      goto blob_open_out;
+    }
+
+    sqlite3_bind_int64((sqlite3_stmt *)v, 1, iRow);
+    rc = sqlite3_step((sqlite3_stmt *)v);
+    if( rc!=SQLITE_ROW ){
+      nAttempt++;
+      rc = sqlite3_finalize((sqlite3_stmt *)v);
+      sqlite3_snprintf(sizeof(zErr), zErr, sqlite3_errmsg(db));
+      v = 0;
+    }
+  } while( nAttempt<5 && rc==SQLITE_SCHEMA );
+
+  if( rc==SQLITE_ROW ){
+    /* The row-record has been opened successfully. Check that the
+    ** column in question contains text or a blob. If it contains
+    ** text, it is up to the caller to get the encoding right.
+    */
+    Incrblob *pBlob;
+    u32 type = v->apCsr[0]->aType[iCol];
+
+    if( type<12 ){
+      sqlite3_snprintf(sizeof(zErr), zErr, "cannot open value of type %s",
+          type==0?"null": type==7?"real": "integer"
+      );
+      rc = SQLITE_ERROR;
+      goto blob_open_out;
+    }
+    pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
+    if( db->mallocFailed ){
+      sqlite3_free(pBlob);
+      goto blob_open_out;
+    }
+    pBlob->flags = flags;
+    pBlob->pCsr =  v->apCsr[0]->pCursor;
+    sqlite3BtreeEnterCursor(pBlob->pCsr);
+    sqlite3BtreeCacheOverflow(pBlob->pCsr);
+    sqlite3BtreeLeaveCursor(pBlob->pCsr);
+    pBlob->pStmt = (sqlite3_stmt *)v;
+    pBlob->iOffset = v->apCsr[0]->aOffset[iCol];
+    pBlob->nByte = sqlite3VdbeSerialTypeLen(type);
+    pBlob->db = db;
+    *ppBlob = (sqlite3_blob *)pBlob;
+    rc = SQLITE_OK;
+  }else if( rc==SQLITE_OK ){
+    sqlite3_snprintf(sizeof(zErr), zErr, "no such rowid: %lld", iRow);
+    rc = SQLITE_ERROR;
+  }
+
+blob_open_out:
+  zErr[sizeof(zErr)-1] = '\0';
+  if( rc!=SQLITE_OK || db->mallocFailed ){
+    sqlite3_finalize((sqlite3_stmt *)v);
+  }
+  sqlite3Error(db, rc, (rc==SQLITE_OK?0:zErr));
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Close a blob handle that was previously created using
+** sqlite3_blob_open().
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  int rc;
+
+  rc = sqlite3_finalize(p->pStmt);
+  sqlite3_free(p);
+  return rc;
+}
+
+/*
+** Perform a read or write operation on a blob
+*/
+static int blobReadWrite(
+  sqlite3_blob *pBlob, 
+  void *z, 
+  int n, 
+  int iOffset, 
+  int (*xCall)(BtCursor*, u32, u32, void*)
+){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  Vdbe *v;
+  sqlite3 *db = p->db;  
+
+  /* Request is out of range. Return a transient error. */
+  if( (iOffset+n)>p->nByte ){
+    return SQLITE_ERROR;
+  }
+  sqlite3_mutex_enter(db->mutex);
+
+  /* If there is no statement handle, then the blob-handle has
+  ** already been invalidated. Return SQLITE_ABORT in this case.
+  */
+  v = (Vdbe*)p->pStmt;
+  if( v==0 ){
+    rc = SQLITE_ABORT;
+  }else{
+    /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is
+    ** returned, clean-up the statement handle.
+    */
+    assert( db == v->db );
+    sqlite3BtreeEnterCursor(p->pCsr);
+    rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
+    sqlite3BtreeLeaveCursor(p->pCsr);
+    if( rc==SQLITE_ABORT ){
+      sqlite3VdbeFinalize(v);
+      p->pStmt = 0;
+    }else{
+      db->errCode = rc;
+      v->rc = rc;
+    }
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Read data from a blob handle.
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *pBlob, void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, z, n, iOffset, sqlite3BtreeData);
+}
+
+/*
+** Write data to a blob handle.
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, (void *)z, n, iOffset, sqlite3BtreePutData);
+}
+
+/*
+** Query a blob handle for the size of the data.
+**
+** The Incrblob.nByte field is fixed for the lifetime of the Incrblob
+** so no mutex is required for access.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  return p->nByte;
+}
+
+#endif /* #ifndef SQLITE_OMIT_INCRBLOB */
+
+/************** End of vdbeblob.c ********************************************/
+/************** Begin file journal.c *****************************************/
+/*
+** 2007 August 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** @(#) $Id: journal.c,v 1.8 2008/05/01 18:01:47 drh Exp $
+*/
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+
+/*
+** This file implements a special kind of sqlite3_file object used
+** by SQLite to create journal files if the atomic-write optimization
+** is enabled.
+**
+** The distinctive characteristic of this sqlite3_file is that the
+** actual on disk file is created lazily. When the file is created,
+** the caller specifies a buffer size for an in-memory buffer to
+** be used to service read() and write() requests. The actual file
+** on disk is not created or populated until either:
+**
+**   1) The in-memory representation grows too large for the allocated 
+**      buffer, or
+**   2) The xSync() method is called.
+*/
+
+
+
+/*
+** A JournalFile object is a subclass of sqlite3_file used by
+** as an open file handle for journal files.
+*/
+struct JournalFile {
+  sqlite3_io_methods *pMethod;    /* I/O methods on journal files */
+  int nBuf;                       /* Size of zBuf[] in bytes */
+  char *zBuf;                     /* Space to buffer journal writes */
+  int iSize;                      /* Amount of zBuf[] currently used */
+  int flags;                      /* xOpen flags */
+  sqlite3_vfs *pVfs;              /* The "real" underlying VFS */
+  sqlite3_file *pReal;            /* The "real" underlying file descriptor */
+  const char *zJournal;           /* Name of the journal file */
+};
+typedef struct JournalFile JournalFile;
+
+/*
+** If it does not already exists, create and populate the on-disk file 
+** for JournalFile p.
+*/
+static int createFile(JournalFile *p){
+  int rc = SQLITE_OK;
+  if( !p->pReal ){
+    sqlite3_file *pReal = (sqlite3_file *)&p[1];
+    rc = sqlite3OsOpen(p->pVfs, p->zJournal, pReal, p->flags, 0);
+    if( rc==SQLITE_OK ){
+      p->pReal = pReal;
+      if( p->iSize>0 ){
+        assert(p->iSize<=p->nBuf);
+        rc = sqlite3OsWrite(p->pReal, p->zBuf, p->iSize, 0);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Close the file.
+*/
+static int jrnlClose(sqlite3_file *pJfd){
+  JournalFile *p = (JournalFile *)pJfd;
+  if( p->pReal ){
+    sqlite3OsClose(p->pReal);
+  }
+  sqlite3_free(p->zBuf);
+  return SQLITE_OK;
+}
+
+/*
+** Read data from the file.
+*/
+static int jrnlRead(
+  sqlite3_file *pJfd,    /* The journal file from which to read */
+  void *zBuf,            /* Put the results here */
+  int iAmt,              /* Number of bytes to read */
+  sqlite_int64 iOfst     /* Begin reading at this offset */
+){
+  int rc = SQLITE_OK;
+  JournalFile *p = (JournalFile *)pJfd;
+  if( p->pReal ){
+    rc = sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
+  }else{
+    assert( iAmt+iOfst<=p->iSize );
+    memcpy(zBuf, &p->zBuf[iOfst], iAmt);
+  }
+  return rc;
+}
+
+/*
+** Write data to the file.
+*/
+static int jrnlWrite(
+  sqlite3_file *pJfd,    /* The journal file into which to write */
+  const void *zBuf,      /* Take data to be written from here */
+  int iAmt,              /* Number of bytes to write */
+  sqlite_int64 iOfst     /* Begin writing at this offset into the file */
+){
+  int rc = SQLITE_OK;
+  JournalFile *p = (JournalFile *)pJfd;
+  if( !p->pReal && (iOfst+iAmt)>p->nBuf ){
+    rc = createFile(p);
+  }
+  if( rc==SQLITE_OK ){
+    if( p->pReal ){
+      rc = sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
+    }else{
+      memcpy(&p->zBuf[iOfst], zBuf, iAmt);
+      if( p->iSize<(iOfst+iAmt) ){
+        p->iSize = (iOfst+iAmt);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Truncate the file.
+*/
+static int jrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size){
+  int rc = SQLITE_OK;
+  JournalFile *p = (JournalFile *)pJfd;
+  if( p->pReal ){
+    rc = sqlite3OsTruncate(p->pReal, size);
+  }else if( size<p->iSize ){
+    p->iSize = size;
+  }
+  return rc;
+}
+
+/*
+** Sync the file.
+*/
+static int jrnlSync(sqlite3_file *pJfd, int flags){
+  int rc;
+  JournalFile *p = (JournalFile *)pJfd;
+  if( p->pReal ){
+    rc = sqlite3OsSync(p->pReal, flags);
+  }else{
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Query the size of the file in bytes.
+*/
+static int jrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){
+  int rc = SQLITE_OK;
+  JournalFile *p = (JournalFile *)pJfd;
+  if( p->pReal ){
+    rc = sqlite3OsFileSize(p->pReal, pSize);
+  }else{
+    *pSize = (sqlite_int64) p->iSize;
+  }
+  return rc;
+}
+
+/*
+** Table of methods for JournalFile sqlite3_file object.
+*/
+static struct sqlite3_io_methods JournalFileMethods = {
+  1,             /* iVersion */
+  jrnlClose,     /* xClose */
+  jrnlRead,      /* xRead */
+  jrnlWrite,     /* xWrite */
+  jrnlTruncate,  /* xTruncate */
+  jrnlSync,      /* xSync */
+  jrnlFileSize,  /* xFileSize */
+  0,             /* xLock */
+  0,             /* xUnlock */
+  0,             /* xCheckReservedLock */
+  0,             /* xFileControl */
+  0,             /* xSectorSize */
+  0              /* xDeviceCharacteristics */
+};
+
+/* 
+** Open a journal file.
+*/
+SQLITE_PRIVATE int sqlite3JournalOpen(
+  sqlite3_vfs *pVfs,         /* The VFS to use for actual file I/O */
+  const char *zName,         /* Name of the journal file */
+  sqlite3_file *pJfd,        /* Preallocated, blank file handle */
+  int flags,                 /* Opening flags */
+  int nBuf                   /* Bytes buffered before opening the file */
+){
+  JournalFile *p = (JournalFile *)pJfd;
+  memset(p, 0, sqlite3JournalSize(pVfs));
+  if( nBuf>0 ){
+    p->zBuf = sqlite3MallocZero(nBuf);
+    if( !p->zBuf ){
+      return SQLITE_NOMEM;
+    }
+  }else{
+    return sqlite3OsOpen(pVfs, zName, pJfd, flags, 0);
+  }
+  p->pMethod = &JournalFileMethods;
+  p->nBuf = nBuf;
+  p->flags = flags;
+  p->zJournal = zName;
+  p->pVfs = pVfs;
+  return SQLITE_OK;
+}
+
+/*
+** If the argument p points to a JournalFile structure, and the underlying
+** file has not yet been created, create it now.
+*/
+SQLITE_PRIVATE int sqlite3JournalCreate(sqlite3_file *p){
+  if( p->pMethods!=&JournalFileMethods ){
+    return SQLITE_OK;
+  }
+  return createFile((JournalFile *)p);
+}
+
+/* 
+** Return the number of bytes required to store a JournalFile that uses vfs
+** pVfs to create the underlying on-disk files.
+*/
+SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *pVfs){
+  return (pVfs->szOsFile+sizeof(JournalFile));
+}
+#endif
+
+/************** End of journal.c *********************************************/
+/************** Begin file expr.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for analyzing expressions and
+** for generating VDBE code that evaluates expressions in SQLite.
+**
+** $Id: expr.c,v 1.371 2008/05/01 17:16:53 drh Exp $
+*/
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the 
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expresssions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr){
+  int op = pExpr->op;
+  if( op==TK_SELECT ){
+    return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr);
+  }
+#ifndef SQLITE_OMIT_CAST
+  if( op==TK_CAST ){
+    return sqlite3AffinityType(&pExpr->token);
+  }
+#endif
+  return pExpr->affinity;
+}
+
+/*
+** Set the collating sequence for expression pExpr to be the collating
+** sequence named by pToken.   Return a pointer to the revised expression.
+** The collating sequence is marked as "explicit" using the EP_ExpCollate
+** flag.  An explicit collating sequence will override implicit
+** collating sequences.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Parse *pParse, Expr *pExpr, Token *pName){
+  char *zColl = 0;            /* Dequoted name of collation sequence */
+  CollSeq *pColl;
+  zColl = sqlite3NameFromToken(pParse->db, pName);
+  if( pExpr && zColl ){
+    pColl = sqlite3LocateCollSeq(pParse, zColl, -1);
+    if( pColl ){
+      pExpr->pColl = pColl;
+      pExpr->flags |= EP_ExpCollate;
+    }
+  }
+  sqlite3_free(zColl);
+  return pExpr;
+}
+
+/*
+** Return the default collation sequence for the expression pExpr. If
+** there is no default collation type, return 0.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
+  CollSeq *pColl = 0;
+  if( pExpr ){
+    int op;
+    pColl = pExpr->pColl;
+    op = pExpr->op;
+    if( (op==TK_CAST || op==TK_UPLUS) && !pColl ){
+      return sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    }
+  }
+  if( sqlite3CheckCollSeq(pParse, pColl) ){ 
+    pColl = 0;
+  }
+  return pColl;
+}
+
+/*
+** pExpr is an operand of a comparison operator.  aff2 is the
+** type affinity of the other operand.  This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+SQLITE_PRIVATE char sqlite3CompareAffinity(Expr *pExpr, char aff2){
+  char aff1 = sqlite3ExprAffinity(pExpr);
+  if( aff1 && aff2 ){
+    /* Both sides of the comparison are columns. If one has numeric
+    ** affinity, use that. Otherwise use no affinity.
+    */
+    if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
+      return SQLITE_AFF_NUMERIC;
+    }else{
+      return SQLITE_AFF_NONE;
+    }
+  }else if( !aff1 && !aff2 ){
+    /* Neither side of the comparison is a column.  Compare the
+    ** results directly.
+    */
+    return SQLITE_AFF_NONE;
+  }else{
+    /* One side is a column, the other is not. Use the columns affinity. */
+    assert( aff1==0 || aff2==0 );
+    return (aff1 + aff2);
+  }
+}
+
+/*
+** pExpr is a comparison operator.  Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(Expr *pExpr){
+  char aff;
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+          pExpr->op==TK_NE );
+  assert( pExpr->pLeft );
+  aff = sqlite3ExprAffinity(pExpr->pLeft);
+  if( pExpr->pRight ){
+    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+  }
+  else if( pExpr->pSelect ){
+    aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff);
+  }
+  else if( !aff ){
+    aff = SQLITE_AFF_NONE;
+  }
+  return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){
+  char aff = comparisonAffinity(pExpr);
+  switch( aff ){
+    case SQLITE_AFF_NONE:
+      return 1;
+    case SQLITE_AFF_TEXT:
+      return idx_affinity==SQLITE_AFF_TEXT;
+    default:
+      return sqlite3IsNumericAffinity(idx_affinity);
+  }
+}
+
+/*
+** Return the P5 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+*/
+static u8 binaryCompareP5(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
+  u8 aff = (char)sqlite3ExprAffinity(pExpr2);
+  aff = sqlite3CompareAffinity(pExpr1, aff) | jumpIfNull;
+  return aff;
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+**
+** Argument pRight (but not pLeft) may be a null pointer. In this case,
+** it is not considered.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(
+  Parse *pParse, 
+  Expr *pLeft, 
+  Expr *pRight
+){
+  CollSeq *pColl;
+  assert( pLeft );
+  if( pLeft->flags & EP_ExpCollate ){
+    assert( pLeft->pColl );
+    pColl = pLeft->pColl;
+  }else if( pRight && pRight->flags & EP_ExpCollate ){
+    assert( pRight->pColl );
+    pColl = pRight->pColl;
+  }else{
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+    if( !pColl ){
+      pColl = sqlite3ExprCollSeq(pParse, pRight);
+    }
+  }
+  return pColl;
+}
+
+/*
+** Generate the operands for a comparison operation.  Before
+** generating the code for each operand, set the EP_AnyAff
+** flag on the expression so that it will be able to used a
+** cached column value that has previously undergone an
+** affinity change.
+*/
+static void codeCompareOperands(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pLeft,      /* The left operand */
+  int *pRegLeft,    /* Register where left operand is stored */
+  int *pFreeLeft,   /* Free this register when done */
+  Expr *pRight,     /* The right operand */
+  int *pRegRight,   /* Register where right operand is stored */
+  int *pFreeRight   /* Write temp register for right operand there */
+){
+  while( pLeft->op==TK_UPLUS ) pLeft = pLeft->pLeft;
+  pLeft->flags |= EP_AnyAff;
+  *pRegLeft = sqlite3ExprCodeTemp(pParse, pLeft, pFreeLeft);
+  while( pRight->op==TK_UPLUS ) pRight = pRight->pLeft;
+  pRight->flags |= EP_AnyAff;
+  *pRegRight = sqlite3ExprCodeTemp(pParse, pRight, pFreeRight);
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+  Parse *pParse,    /* The parsing (and code generating) context */
+  Expr *pLeft,      /* The left operand */
+  Expr *pRight,     /* The right operand */
+  int opcode,       /* The comparison opcode */
+  int in1, int in2, /* Register holding operands */
+  int dest,         /* Jump here if true.  */
+  int jumpIfNull    /* If true, jump if either operand is NULL */
+){
+  int p5;
+  int addr;
+  CollSeq *p4;
+
+  p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
+  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
+  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
+                           (void*)p4, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(pParse->pVdbe, p5);
+  if( p5 & SQLITE_AFF_MASK ){
+    sqlite3ExprCacheAffinityChange(pParse, in1, 1);
+    sqlite3ExprCacheAffinityChange(pParse, in2, 1);
+  }
+  return addr;
+}
+
+/*
+** Construct a new expression node and return a pointer to it.  Memory
+** for this node is obtained from sqlite3_malloc().  The calling function
+** is responsible for making sure the node eventually gets freed.
+*/
+SQLITE_PRIVATE Expr *sqlite3Expr(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight,           /* Right operand */
+  const Token *pToken     /* Argument token */
+){
+  Expr *pNew;
+  pNew = sqlite3DbMallocZero(db, sizeof(Expr));
+  if( pNew==0 ){
+    /* When malloc fails, delete pLeft and pRight. Expressions passed to 
+    ** this function must always be allocated with sqlite3Expr() for this 
+    ** reason. 
+    */
+    sqlite3ExprDelete(pLeft);
+    sqlite3ExprDelete(pRight);
+    return 0;
+  }
+  pNew->op = op;
+  pNew->pLeft = pLeft;
+  pNew->pRight = pRight;
+  pNew->iAgg = -1;
+  if( pToken ){
+    assert( pToken->dyn==0 );
+    pNew->span = pNew->token = *pToken;
+  }else if( pLeft ){
+    if( pRight ){
+      sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
+      if( pRight->flags & EP_ExpCollate ){
+        pNew->flags |= EP_ExpCollate;
+        pNew->pColl = pRight->pColl;
+      }
+    }
+    if( pLeft->flags & EP_ExpCollate ){
+      pNew->flags |= EP_ExpCollate;
+      pNew->pColl = pLeft->pColl;
+    }
+  }
+
+  sqlite3ExprSetHeight(pNew);
+  return pNew;
+}
+
+/*
+** Works like sqlite3Expr() except that it takes an extra Parse*
+** argument and notifies the associated connection object if malloc fails.
+*/
+SQLITE_PRIVATE Expr *sqlite3PExpr(
+  Parse *pParse,          /* Parsing context */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight,           /* Right operand */
+  const Token *pToken     /* Argument token */
+){
+  return sqlite3Expr(pParse->db, op, pLeft, pRight, pToken);
+}
+
+/*
+** When doing a nested parse, you can include terms in an expression
+** that look like this:   #1 #2 ...  These terms refer to registers
+** in the virtual machine.  #N is the N-th register.
+**
+** This routine is called by the parser to deal with on of those terms.
+** It immediately generates code to store the value in a memory location.
+** The returns an expression that will code to extract the value from
+** that memory location as needed.
+*/
+SQLITE_PRIVATE Expr *sqlite3RegisterExpr(Parse *pParse, Token *pToken){
+  Vdbe *v = pParse->pVdbe;
+  Expr *p;
+  if( pParse->nested==0 ){
+    sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", pToken);
+    return sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
+  }
+  if( v==0 ) return 0;
+  p = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, pToken);
+  if( p==0 ){
+    return 0;  /* Malloc failed */
+  }
+  p->iTable = atoi((char*)&pToken->z[1]);
+  return p;
+}
+
+/*
+** Join two expressions using an AND operator.  If either expression is
+** NULL, then just return the other expression.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
+  if( pLeft==0 ){
+    return pRight;
+  }else if( pRight==0 ){
+    return pLeft;
+  }else{
+    return sqlite3Expr(db, TK_AND, pLeft, pRight, 0);
+  }
+}
+
+/*
+** Set the Expr.span field of the given expression to span all
+** text between the two given tokens.
+*/
+SQLITE_PRIVATE void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
+  assert( pRight!=0 );
+  assert( pLeft!=0 );
+  if( pExpr && pRight->z && pLeft->z ){
+    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
+    if( pLeft->dyn==0 && pRight->dyn==0 ){
+      pExpr->span.z = pLeft->z;
+      pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
+    }else{
+      pExpr->span.z = 0;
+    }
+  }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *pToken){
+  Expr *pNew;
+  assert( pToken );
+  pNew = sqlite3DbMallocZero(pParse->db, sizeof(Expr) );
+  if( pNew==0 ){
+    sqlite3ExprListDelete(pList); /* Avoid leaking memory when malloc fails */
+    return 0;
+  }
+  pNew->op = TK_FUNCTION;
+  pNew->pList = pList;
+  assert( pToken->dyn==0 );
+  pNew->token = *pToken;
+  pNew->span = pNew->token;
+
+  sqlite3ExprSetHeight(pNew);
+  return pNew;
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.  
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
+** sure "nnn" is not too be to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa" or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard.  Or if this is the first
+** instance of the wildcard, the next sequenial variable number is
+** assigned.
+*/
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
+  Token *pToken;
+  sqlite3 *db = pParse->db;
+
+  if( pExpr==0 ) return;
+  pToken = &pExpr->token;
+  assert( pToken->n>=1 );
+  assert( pToken->z!=0 );
+  assert( pToken->z[0]!=0 );
+  if( pToken->n==1 ){
+    /* Wildcard of the form "?".  Assign the next variable number */
+    pExpr->iTable = ++pParse->nVar;
+  }else if( pToken->z[0]=='?' ){
+    /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+    ** use it as the variable number */
+    int i;
+    pExpr->iTable = i = atoi((char*)&pToken->z[1]);
+    testcase( i==0 );
+    testcase( i==1 );
+    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
+    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
+    if( i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+      sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+          db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
+    }
+    if( i>pParse->nVar ){
+      pParse->nVar = i;
+    }
+  }else{
+    /* Wildcards of the form ":aaa" or "$aaa".  Reuse the same variable
+    ** number as the prior appearance of the same name, or if the name
+    ** has never appeared before, reuse the same variable number
+    */
+    int i, n;
+    n = pToken->n;
+    for(i=0; i<pParse->nVarExpr; i++){
+      Expr *pE;
+      if( (pE = pParse->apVarExpr[i])!=0
+          && pE->token.n==n
+          && memcmp(pE->token.z, pToken->z, n)==0 ){
+        pExpr->iTable = pE->iTable;
+        break;
+      }
+    }
+    if( i>=pParse->nVarExpr ){
+      pExpr->iTable = ++pParse->nVar;
+      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
+        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
+        pParse->apVarExpr =
+            sqlite3DbReallocOrFree(
+              db,
+              pParse->apVarExpr,
+              pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0])
+            );
+      }
+      if( !db->mallocFailed ){
+        assert( pParse->apVarExpr!=0 );
+        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
+      }
+    }
+  } 
+  if( !pParse->nErr && pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+    sqlite3ErrorMsg(pParse, "too many SQL variables");
+  }
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+SQLITE_PRIVATE void sqlite3ExprDelete(Expr *p){
+  if( p==0 ) return;
+  if( p->span.dyn ) sqlite3_free((char*)p->span.z);
+  if( p->token.dyn ) sqlite3_free((char*)p->token.z);
+  sqlite3ExprDelete(p->pLeft);
+  sqlite3ExprDelete(p->pRight);
+  sqlite3ExprListDelete(p->pList);
+  sqlite3SelectDelete(p->pSelect);
+  sqlite3_free(p);
+}
+
+/*
+** The Expr.token field might be a string literal that is quoted.
+** If so, remove the quotation marks.
+*/
+SQLITE_PRIVATE void sqlite3DequoteExpr(sqlite3 *db, Expr *p){
+  if( ExprHasAnyProperty(p, EP_Dequoted) ){
+    return;
+  }
+  ExprSetProperty(p, EP_Dequoted);
+  if( p->token.dyn==0 ){
+    sqlite3TokenCopy(db, &p->token, &p->token);
+  }
+  sqlite3Dequote((char*)p->token.z);
+}
+
+
+/*
+** The following group of routines make deep copies of expressions,
+** expression lists, ID lists, and select statements.  The copies can
+** be deleted (by being passed to their respective ...Delete() routines)
+** without effecting the originals.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded 
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, Expr *p){
+  Expr *pNew;
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRaw(db, sizeof(*p) );
+  if( pNew==0 ) return 0;
+  memcpy(pNew, p, sizeof(*pNew));
+  if( p->token.z!=0 ){
+    pNew->token.z = (u8*)sqlite3DbStrNDup(db, (char*)p->token.z, p->token.n);
+    pNew->token.dyn = 1;
+  }else{
+    assert( pNew->token.z==0 );
+  }
+  pNew->span.z = 0;
+  pNew->pLeft = sqlite3ExprDup(db, p->pLeft);
+  pNew->pRight = sqlite3ExprDup(db, p->pRight);
+  pNew->pList = sqlite3ExprListDup(db, p->pList);
+  pNew->pSelect = sqlite3SelectDup(db, p->pSelect);
+  return pNew;
+}
+SQLITE_PRIVATE void sqlite3TokenCopy(sqlite3 *db, Token *pTo, Token *pFrom){
+  if( pTo->dyn ) sqlite3_free((char*)pTo->z);
+  if( pFrom->z ){
+    pTo->n = pFrom->n;
+    pTo->z = (u8*)sqlite3DbStrNDup(db, (char*)pFrom->z, pFrom->n);
+    pTo->dyn = 1;
+  }else{
+    pTo->z = 0;
+  }
+}
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p){
+  ExprList *pNew;
+  struct ExprList_item *pItem, *pOldItem;
+  int i;
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->iECursor = 0;
+  pNew->nExpr = pNew->nAlloc = p->nExpr;
+  pNew->a = pItem = sqlite3DbMallocRaw(db,  p->nExpr*sizeof(p->a[0]) );
+  if( pItem==0 ){
+    sqlite3_free(pNew);
+    return 0;
+  } 
+  pOldItem = p->a;
+  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+    Expr *pNewExpr, *pOldExpr;
+    pItem->pExpr = pNewExpr = sqlite3ExprDup(db, pOldExpr = pOldItem->pExpr);
+    if( pOldExpr->span.z!=0 && pNewExpr ){
+      /* Always make a copy of the span for top-level expressions in the
+      ** expression list.  The logic in SELECT processing that determines
+      ** the names of columns in the result set needs this information */
+      sqlite3TokenCopy(db, &pNewExpr->span, &pOldExpr->span);
+    }
+    assert( pNewExpr==0 || pNewExpr->span.z!=0 
+            || pOldExpr->span.z==0
+            || db->mallocFailed );
+    pItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pItem->sortOrder = pOldItem->sortOrder;
+    pItem->isAgg = pOldItem->isAgg;
+    pItem->done = 0;
+  }
+  return pNew;
+}
+
+/*
+** If cursors, triggers, views and subqueries are all omitted from
+** the build, then none of the following routines, except for 
+** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
+** called with a NULL argument.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
+ || !defined(SQLITE_OMIT_SUBQUERY)
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p){
+  SrcList *pNew;
+  int i;
+  int nByte;
+  if( p==0 ) return 0;
+  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+  pNew = sqlite3DbMallocRaw(db, nByte );
+  if( pNew==0 ) return 0;
+  pNew->nSrc = pNew->nAlloc = p->nSrc;
+  for(i=0; i<p->nSrc; i++){
+    struct SrcList_item *pNewItem = &pNew->a[i];
+    struct SrcList_item *pOldItem = &p->a[i];
+    Table *pTab;
+    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
+    pNewItem->jointype = pOldItem->jointype;
+    pNewItem->iCursor = pOldItem->iCursor;
+    pNewItem->isPopulated = pOldItem->isPopulated;
+    pTab = pNewItem->pTab = pOldItem->pTab;
+    if( pTab ){
+      pTab->nRef++;
+    }
+    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect);
+    pNewItem->pOn = sqlite3ExprDup(db, pOldItem->pOn);
+    pNewItem->pUsing = sqlite3IdListDup(db, pOldItem->pUsing);
+    pNewItem->colUsed = pOldItem->colUsed;
+  }
+  return pNew;
+}
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, IdList *p){
+  IdList *pNew;
+  int i;
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->nId = pNew->nAlloc = p->nId;
+  pNew->a = sqlite3DbMallocRaw(db, p->nId*sizeof(p->a[0]) );
+  if( pNew->a==0 ){
+    sqlite3_free(pNew);
+    return 0;
+  }
+  for(i=0; i<p->nId; i++){
+    struct IdList_item *pNewItem = &pNew->a[i];
+    struct IdList_item *pOldItem = &p->a[i];
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->idx = pOldItem->idx;
+  }
+  return pNew;
+}
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
+  Select *pNew;
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRaw(db, sizeof(*p) );
+  if( pNew==0 ) return 0;
+  pNew->isDistinct = p->isDistinct;
+  pNew->pEList = sqlite3ExprListDup(db, p->pEList);
+  pNew->pSrc = sqlite3SrcListDup(db, p->pSrc);
+  pNew->pWhere = sqlite3ExprDup(db, p->pWhere);
+  pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy);
+  pNew->pHaving = sqlite3ExprDup(db, p->pHaving);
+  pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy);
+  pNew->op = p->op;
+  pNew->pPrior = sqlite3SelectDup(db, p->pPrior);
+  pNew->pLimit = sqlite3ExprDup(db, p->pLimit);
+  pNew->pOffset = sqlite3ExprDup(db, p->pOffset);
+  pNew->iLimit = -1;
+  pNew->iOffset = -1;
+  pNew->isResolved = p->isResolved;
+  pNew->isAgg = p->isAgg;
+  pNew->usesEphm = 0;
+  pNew->disallowOrderBy = 0;
+  pNew->pRightmost = 0;
+  pNew->addrOpenEphm[0] = -1;
+  pNew->addrOpenEphm[1] = -1;
+  pNew->addrOpenEphm[2] = -1;
+  return pNew;
+}
+#else
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
+  assert( p==0 );
+  return 0;
+}
+#endif
+
+
+/*
+** Add a new element to the end of an expression list.  If pList is
+** initially NULL, then create a new expression list.
+*/
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr,            /* Expression to be appended */
+  Token *pName            /* AS keyword for the expression */
+){
+  sqlite3 *db = pParse->db;
+  if( pList==0 ){
+    pList = sqlite3DbMallocZero(db, sizeof(ExprList) );
+    if( pList==0 ){
+      goto no_mem;
+    }
+    assert( pList->nAlloc==0 );
+  }
+  if( pList->nAlloc<=pList->nExpr ){
+    struct ExprList_item *a;
+    int n = pList->nAlloc*2 + 4;
+    a = sqlite3DbRealloc(db, pList->a, n*sizeof(pList->a[0]));
+    if( a==0 ){
+      goto no_mem;
+    }
+    pList->a = a;
+    pList->nAlloc = n;
+  }
+  assert( pList->a!=0 );
+  if( pExpr || pName ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr++];
+    memset(pItem, 0, sizeof(*pItem));
+    pItem->zName = sqlite3NameFromToken(db, pName);
+    pItem->pExpr = pExpr;
+  }
+  return pList;
+
+no_mem:     
+  /* Avoid leaking memory if malloc has failed. */
+  sqlite3ExprDelete(pExpr);
+  sqlite3ExprListDelete(pList);
+  return 0;
+}
+
+/*
+** If the expression list pEList contains more than iLimit elements,
+** leave an error message in pParse.
+*/
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(
+  Parse *pParse,
+  ExprList *pEList,
+  const char *zObject
+){
+  int mx = pParse->db->aLimit[SQLITE_LIMIT_COLUMN];
+  testcase( pEList && pEList->nExpr==mx );
+  testcase( pEList && pEList->nExpr==mx+1 );
+  if( pEList && pEList->nExpr>mx ){
+    sqlite3ErrorMsg(pParse, "too many columns in %s", zObject);
+  }
+}
+
+
+/* The following three functions, heightOfExpr(), heightOfExprList()
+** and heightOfSelect(), are used to determine the maximum height
+** of any expression tree referenced by the structure passed as the
+** first argument.
+**
+** If this maximum height is greater than the current value pointed
+** to by pnHeight, the second parameter, then set *pnHeight to that
+** value.
+*/
+static void heightOfExpr(Expr *p, int *pnHeight){
+  if( p ){
+    if( p->nHeight>*pnHeight ){
+      *pnHeight = p->nHeight;
+    }
+  }
+}
+static void heightOfExprList(ExprList *p, int *pnHeight){
+  if( p ){
+    int i;
+    for(i=0; i<p->nExpr; i++){
+      heightOfExpr(p->a[i].pExpr, pnHeight);
+    }
+  }
+}
+static void heightOfSelect(Select *p, int *pnHeight){
+  if( p ){
+    heightOfExpr(p->pWhere, pnHeight);
+    heightOfExpr(p->pHaving, pnHeight);
+    heightOfExpr(p->pLimit, pnHeight);
+    heightOfExpr(p->pOffset, pnHeight);
+    heightOfExprList(p->pEList, pnHeight);
+    heightOfExprList(p->pGroupBy, pnHeight);
+    heightOfExprList(p->pOrderBy, pnHeight);
+    heightOfSelect(p->pPrior, pnHeight);
+  }
+}
+
+/*
+** Set the Expr.nHeight variable in the structure passed as an 
+** argument. An expression with no children, Expr.pList or 
+** Expr.pSelect member has a height of 1. Any other expression
+** has a height equal to the maximum height of any other 
+** referenced Expr plus one.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetHeight(Expr *p){
+  int nHeight = 0;
+  heightOfExpr(p->pLeft, &nHeight);
+  heightOfExpr(p->pRight, &nHeight);
+  heightOfExprList(p->pList, &nHeight);
+  heightOfSelect(p->pSelect, &nHeight);
+  p->nHeight = nHeight + 1;
+}
+
+/*
+** Return the maximum height of any expression tree referenced
+** by the select statement passed as an argument.
+*/
+SQLITE_PRIVATE int sqlite3SelectExprHeight(Select *p){
+  int nHeight = 0;
+  heightOfSelect(p, &nHeight);
+  return nHeight;
+}
+
+/*
+** Delete an entire expression list.
+*/
+SQLITE_PRIVATE void sqlite3ExprListDelete(ExprList *pList){
+  int i;
+  struct ExprList_item *pItem;
+  if( pList==0 ) return;
+  assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
+  assert( pList->nExpr<=pList->nAlloc );
+  for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+    sqlite3ExprDelete(pItem->pExpr);
+    sqlite3_free(pItem->zName);
+  }
+  sqlite3_free(pList->a);
+  sqlite3_free(pList);
+}
+
+/*
+** Walk an expression tree.  Call xFunc for each node visited.  xFunc
+** is called on the node before xFunc is called on the nodes children.
+**
+** The return value from xFunc determines whether the tree walk continues.
+** 0 means continue walking the tree.  1 means do not walk children
+** of the current node but continue with siblings.  2 means abandon
+** the tree walk completely.
+**
+** The return value from this routine is 1 to abandon the tree walk
+** and 0 to continue.
+**
+** NOTICE:  This routine does *not* descend into subqueries.
+*/
+static int walkExprList(ExprList *, int (*)(void *, Expr*), void *);
+static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){
+  int rc;
+  if( pExpr==0 ) return 0;
+  rc = (*xFunc)(pArg, pExpr);
+  if( rc==0 ){
+    if( walkExprTree(pExpr->pLeft, xFunc, pArg) ) return 1;
+    if( walkExprTree(pExpr->pRight, xFunc, pArg) ) return 1;
+    if( walkExprList(pExpr->pList, xFunc, pArg) ) return 1;
+  }
+  return rc>1;
+}
+
+/*
+** Call walkExprTree() for every expression in list p.
+*/
+static int walkExprList(ExprList *p, int (*xFunc)(void *, Expr*), void *pArg){
+  int i;
+  struct ExprList_item *pItem;
+  if( !p ) return 0;
+  for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
+    if( walkExprTree(pItem->pExpr, xFunc, pArg) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Call walkExprTree() for every expression in Select p, not including
+** expressions that are part of sub-selects in any FROM clause or the LIMIT
+** or OFFSET expressions..
+*/
+static int walkSelectExpr(Select *p, int (*xFunc)(void *, Expr*), void *pArg){
+  walkExprList(p->pEList, xFunc, pArg);
+  walkExprTree(p->pWhere, xFunc, pArg);
+  walkExprList(p->pGroupBy, xFunc, pArg);
+  walkExprTree(p->pHaving, xFunc, pArg);
+  walkExprList(p->pOrderBy, xFunc, pArg);
+  if( p->pPrior ){
+    walkSelectExpr(p->pPrior, xFunc, pArg);
+  }
+  return 0;
+}
+
+
+/*
+** This routine is designed as an xFunc for walkExprTree().
+**
+** pArg is really a pointer to an integer.  If we can tell by looking
+** at pExpr that the expression that contains pExpr is not a constant
+** expression, then set *pArg to 0 and return 2 to abandon the tree walk.
+** If pExpr does does not disqualify the expression from being a constant
+** then do nothing.
+**
+** After walking the whole tree, if no nodes are found that disqualify
+** the expression as constant, then we assume the whole expression
+** is constant.  See sqlite3ExprIsConstant() for additional information.
+*/
+static int exprNodeIsConstant(void *pArg, Expr *pExpr){
+  int *pN = (int*)pArg;
+
+  /* If *pArg is 3 then any term of the expression that comes from
+  ** the ON or USING clauses of a join disqualifies the expression
+  ** from being considered constant. */
+  if( (*pN)==3 && ExprHasAnyProperty(pExpr, EP_FromJoin) ){
+    *pN = 0;
+    return 2;
+  }
+
+  switch( pExpr->op ){
+    /* Consider functions to be constant if all their arguments are constant
+    ** and *pArg==2 */
+    case TK_FUNCTION:
+      if( (*pN)==2 ) return 0;
+      /* Fall through */
+    case TK_ID:
+    case TK_COLUMN:
+    case TK_DOT:
+    case TK_AGG_FUNCTION:
+    case TK_AGG_COLUMN:
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:
+      testcase( pExpr->op==TK_SELECT );
+      testcase( pExpr->op==TK_EXISTS );
+#endif
+      testcase( pExpr->op==TK_ID );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_DOT );
+      testcase( pExpr->op==TK_AGG_FUNCTION );
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      *pN = 0;
+      return 2;
+    case TK_IN:
+      if( pExpr->pSelect ){
+        *pN = 0;
+        return 2;
+      }
+    default:
+      return 0;
+  }
+}
+
+/*
+** Walk an expression tree.  Return 1 if the expression is constant
+** and 0 if it involves variables or function calls.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr *p){
+  int isConst = 1;
+  walkExprTree(p, exprNodeIsConstant, &isConst);
+  return isConst;
+}
+
+/*
+** Walk an expression tree.  Return 1 if the expression is constant
+** that does no originate from the ON or USING clauses of a join.
+** Return 0 if it involves variables or function calls or terms from
+** an ON or USING clause.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr *p){
+  int isConst = 3;
+  walkExprTree(p, exprNodeIsConstant, &isConst);
+  return isConst!=0;
+}
+
+/*
+** Walk an expression tree.  Return 1 if the expression is constant
+** or a function call with constant arguments.  Return and 0 if there
+** are any variables.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr *p){
+  int isConst = 2;
+  walkExprTree(p, exprNodeIsConstant, &isConst);
+  return isConst!=0;
+}
+
+/*
+** If the expression p codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue.  If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr *p, int *pValue){
+  switch( p->op ){
+    case TK_INTEGER: {
+      if( sqlite3GetInt32((char*)p->token.z, pValue) ){
+        return 1;
+      }
+      break;
+    }
+    case TK_UPLUS: {
+      return sqlite3ExprIsInteger(p->pLeft, pValue);
+    }
+    case TK_UMINUS: {
+      int v;
+      if( sqlite3ExprIsInteger(p->pLeft, &v) ){
+        *pValue = -v;
+        return 1;
+      }
+      break;
+    }
+    default: break;
+  }
+  return 0;
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+SQLITE_PRIVATE int sqlite3IsRowid(const char *z){
+  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+  return 0;
+}
+
+/*
+** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
+** that name in the set of source tables in pSrcList and make the pExpr 
+** expression node refer back to that source column.  The following changes
+** are made to pExpr:
+**
+**    pExpr->iDb           Set the index in db->aDb[] of the database holding
+**                         the table.
+**    pExpr->iTable        Set to the cursor number for the table obtained
+**                         from pSrcList.
+**    pExpr->iColumn       Set to the column number within the table.
+**    pExpr->op            Set to TK_COLUMN.
+**    pExpr->pLeft         Any expression this points to is deleted
+**    pExpr->pRight        Any expression this points to is deleted.
+**
+** The pDbToken is the name of the database (the "X").  This value may be
+** NULL meaning that name is of the form Y.Z or Z.  Any available database
+** can be used.  The pTableToken is the name of the table (the "Y").  This
+** value can be NULL if pDbToken is also NULL.  If pTableToken is NULL it
+** means that the form of the name is Z and that columns from any table
+** can be used.
+**
+** If the name cannot be resolved unambiguously, leave an error message
+** in pParse and return non-zero.  Return zero on success.
+*/
+static int lookupName(
+  Parse *pParse,       /* The parsing context */
+  Token *pDbToken,     /* Name of the database containing table, or NULL */
+  Token *pTableToken,  /* Name of table containing column, or NULL */
+  Token *pColumnToken, /* Name of the column. */
+  NameContext *pNC,    /* The name context used to resolve the name */
+  Expr *pExpr          /* Make this EXPR node point to the selected column */
+){
+  char *zDb = 0;       /* Name of the database.  The "X" in X.Y.Z */
+  char *zTab = 0;      /* Name of the table.  The "Y" in X.Y.Z or Y.Z */
+  char *zCol = 0;      /* Name of the column.  The "Z" */
+  int i, j;            /* Loop counters */
+  int cnt = 0;         /* Number of matching column names */
+  int cntTab = 0;      /* Number of matching table names */
+  sqlite3 *db = pParse->db;  /* The database */
+  struct SrcList_item *pItem;       /* Use for looping over pSrcList items */
+  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
+  NameContext *pTopNC = pNC;        /* First namecontext in the list */
+  Schema *pSchema = 0;              /* Schema of the expression */
+
+  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
+  zDb = sqlite3NameFromToken(db, pDbToken);
+  zTab = sqlite3NameFromToken(db, pTableToken);
+  zCol = sqlite3NameFromToken(db, pColumnToken);
+  if( db->mallocFailed ){
+    goto lookupname_end;
+  }
+
+  pExpr->iTable = -1;
+  while( pNC && cnt==0 ){
+    ExprList *pEList;
+    SrcList *pSrcList = pNC->pSrcList;
+
+    if( pSrcList ){
+      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
+        Table *pTab;
+        int iDb;
+        Column *pCol;
+  
+        pTab = pItem->pTab;
+        assert( pTab!=0 );
+        iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+        assert( pTab->nCol>0 );
+        if( zTab ){
+          if( pItem->zAlias ){
+            char *zTabName = pItem->zAlias;
+            if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+          }else{
+            char *zTabName = pTab->zName;
+            if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+            if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
+              continue;
+            }
+          }
+        }
+        if( 0==(cntTab++) ){
+          pExpr->iTable = pItem->iCursor;
+          pSchema = pTab->pSchema;
+          pMatch = pItem;
+        }
+        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+            const char *zColl = pTab->aCol[j].zColl;
+            IdList *pUsing;
+            cnt++;
+            pExpr->iTable = pItem->iCursor;
+            pMatch = pItem;
+            pSchema = pTab->pSchema;
+            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+            pExpr->affinity = pTab->aCol[j].affinity;
+            if( (pExpr->flags & EP_ExpCollate)==0 ){
+              pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
+            }
+            if( i<pSrcList->nSrc-1 ){
+              if( pItem[1].jointype & JT_NATURAL ){
+                /* If this match occurred in the left table of a natural join,
+                ** then skip the right table to avoid a duplicate match */
+                pItem++;
+                i++;
+              }else if( (pUsing = pItem[1].pUsing)!=0 ){
+                /* If this match occurs on a column that is in the USING clause
+                ** of a join, skip the search of the right table of the join
+                ** to avoid a duplicate match there. */
+                int k;
+                for(k=0; k<pUsing->nId; k++){
+                  if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
+                    pItem++;
+                    i++;
+                    break;
+                  }
+                }
+              }
+            }
+            break;
+          }
+        }
+      }
+    }
+
+#ifndef SQLITE_OMIT_TRIGGER
+    /* If we have not already resolved the name, then maybe 
+    ** it is a new.* or old.* trigger argument reference
+    */
+    if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
+      TriggerStack *pTriggerStack = pParse->trigStack;
+      Table *pTab = 0;
+      u32 *piColMask;
+      if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){
+        pExpr->iTable = pTriggerStack->newIdx;
+        assert( pTriggerStack->pTab );
+        pTab = pTriggerStack->pTab;
+        piColMask = &(pTriggerStack->newColMask);
+      }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){
+        pExpr->iTable = pTriggerStack->oldIdx;
+        assert( pTriggerStack->pTab );
+        pTab = pTriggerStack->pTab;
+        piColMask = &(pTriggerStack->oldColMask);
+      }
+
+      if( pTab ){ 
+        int iCol;
+        Column *pCol = pTab->aCol;
+
+        pSchema = pTab->pSchema;
+        cntTab++;
+        for(iCol=0; iCol < pTab->nCol; iCol++, pCol++) {
+          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+            const char *zColl = pTab->aCol[iCol].zColl;
+            cnt++;
+            pExpr->iColumn = iCol==pTab->iPKey ? -1 : iCol;
+            pExpr->affinity = pTab->aCol[iCol].affinity;
+            if( (pExpr->flags & EP_ExpCollate)==0 ){
+              pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
+            }
+            pExpr->pTab = pTab;
+            if( iCol>=0 ){
+              testcase( iCol==31 );
+              testcase( iCol==32 );
+              *piColMask |= ((u32)1<<iCol) | (iCol>=32?0xffffffff:0);
+            }
+            break;
+          }
+        }
+      }
+    }
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+
+    /*
+    ** Perhaps the name is a reference to the ROWID
+    */
+    if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
+      cnt = 1;
+      pExpr->iColumn = -1;
+      pExpr->affinity = SQLITE_AFF_INTEGER;
+    }
+
+    /*
+    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
+    ** might refer to an result-set alias.  This happens, for example, when
+    ** we are resolving names in the WHERE clause of the following command:
+    **
+    **     SELECT a+b AS x FROM table WHERE x<10;
+    **
+    ** In cases like this, replace pExpr with a copy of the expression that
+    ** forms the result set entry ("a+b" in the example) and return immediately.
+    ** Note that the expression in the result set should have already been
+    ** resolved by the time the WHERE clause is resolved.
+    */
+    if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){
+      for(j=0; j<pEList->nExpr; j++){
+        char *zAs = pEList->a[j].zName;
+        if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
+          Expr *pDup, *pOrig;
+          assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+          assert( pExpr->pList==0 );
+          assert( pExpr->pSelect==0 );
+          pOrig = pEList->a[j].pExpr;
+          if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
+            sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
+            sqlite3_free(zCol);
+            return 2;
+          }
+          pDup = sqlite3ExprDup(db, pOrig);
+          if( pExpr->flags & EP_ExpCollate ){
+            pDup->pColl = pExpr->pColl;
+            pDup->flags |= EP_ExpCollate;
+          }
+          if( pExpr->span.dyn ) sqlite3_free((char*)pExpr->span.z);
+          if( pExpr->token.dyn ) sqlite3_free((char*)pExpr->token.z);
+          memcpy(pExpr, pDup, sizeof(*pExpr));
+          sqlite3_free(pDup);
+          cnt = 1;
+          pMatch = 0;
+          assert( zTab==0 && zDb==0 );
+          goto lookupname_end_2;
+        }
+      } 
+    }
+
+    /* Advance to the next name context.  The loop will exit when either
+    ** we have a match (cnt>0) or when we run out of name contexts.
+    */
+    if( cnt==0 ){
+      pNC = pNC->pNext;
+    }
+  }
+
+  /*
+  ** If X and Y are NULL (in other words if only the column name Z is
+  ** supplied) and the value of Z is enclosed in double-quotes, then
+  ** Z is a string literal if it doesn't match any column names.  In that
+  ** case, we need to return right away and not make any changes to
+  ** pExpr.
+  **
+  ** Because no reference was made to outer contexts, the pNC->nRef
+  ** fields are not changed in any context.
+  */
+  if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
+    sqlite3_free(zCol);
+    return 0;
+  }
+
+  /*
+  ** cnt==0 means there was not match.  cnt>1 means there were two or
+  ** more matches.  Either way, we have an error.
+  */
+  if( cnt!=1 ){
+    const char *zErr;
+    zErr = cnt==0 ? "no such column" : "ambiguous column name";
+    if( zDb ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
+    }else if( zTab ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
+    }
+    pTopNC->nErr++;
+  }
+
+  /* If a column from a table in pSrcList is referenced, then record
+  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
+  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
+  ** column number is greater than the number of bits in the bitmask
+  ** then set the high-order bit of the bitmask.
+  */
+  if( pExpr->iColumn>=0 && pMatch!=0 ){
+    int n = pExpr->iColumn;
+    testcase( n==sizeof(Bitmask)*8-1 );
+    if( n>=sizeof(Bitmask)*8 ){
+      n = sizeof(Bitmask)*8-1;
+    }
+    assert( pMatch->iCursor==pExpr->iTable );
+    pMatch->colUsed |= ((Bitmask)1)<<n;
+  }
+
+lookupname_end:
+  /* Clean up and return
+  */
+  sqlite3_free(zDb);
+  sqlite3_free(zTab);
+  sqlite3ExprDelete(pExpr->pLeft);
+  pExpr->pLeft = 0;
+  sqlite3ExprDelete(pExpr->pRight);
+  pExpr->pRight = 0;
+  pExpr->op = TK_COLUMN;
+lookupname_end_2:
+  sqlite3_free(zCol);
+  if( cnt==1 ){
+    assert( pNC!=0 );
+    sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
+    if( pMatch && !pMatch->pSelect ){
+      pExpr->pTab = pMatch->pTab;
+    }
+    /* Increment the nRef value on all name contexts from TopNC up to
+    ** the point where the name matched. */
+    for(;;){
+      assert( pTopNC!=0 );
+      pTopNC->nRef++;
+      if( pTopNC==pNC ) break;
+      pTopNC = pTopNC->pNext;
+    }
+    return 0;
+  } else {
+    return 1;
+  }
+}
+
+/*
+** This routine is designed as an xFunc for walkExprTree().
+**
+** Resolve symbolic names into TK_COLUMN operators for the current
+** node in the expression tree.  Return 0 to continue the search down
+** the tree or 2 to abort the tree walk.
+**
+** This routine also does error checking and name resolution for
+** function names.  The operator for aggregate functions is changed
+** to TK_AGG_FUNCTION.
+*/
+static int nameResolverStep(void *pArg, Expr *pExpr){
+  NameContext *pNC = (NameContext*)pArg;
+  Parse *pParse;
+
+  if( pExpr==0 ) return 1;
+  assert( pNC!=0 );
+  pParse = pNC->pParse;
+
+  if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return 1;
+  ExprSetProperty(pExpr, EP_Resolved);
+#ifndef NDEBUG
+  if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
+    SrcList *pSrcList = pNC->pSrcList;
+    int i;
+    for(i=0; i<pNC->pSrcList->nSrc; i++){
+      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
+    }
+  }
+#endif
+  switch( pExpr->op ){
+    /* Double-quoted strings (ex: "abc") are used as identifiers if
+    ** possible.  Otherwise they remain as strings.  Single-quoted
+    ** strings (ex: 'abc') are always string literals.
+    */
+    case TK_STRING: {
+      if( pExpr->token.z[0]=='\'' ) break;
+      /* Fall thru into the TK_ID case if this is a double-quoted string */
+    }
+    /* A lone identifier is the name of a column.
+    */
+    case TK_ID: {
+      lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr);
+      return 1;
+    }
+  
+    /* A table name and column name:     ID.ID
+    ** Or a database, table and column:  ID.ID.ID
+    */
+    case TK_DOT: {
+      Token *pColumn;
+      Token *pTable;
+      Token *pDb;
+      Expr *pRight;
+
+      /* if( pSrcList==0 ) break; */
+      pRight = pExpr->pRight;
+      if( pRight->op==TK_ID ){
+        pDb = 0;
+        pTable = &pExpr->pLeft->token;
+        pColumn = &pRight->token;
+      }else{
+        assert( pRight->op==TK_DOT );
+        pDb = &pExpr->pLeft->token;
+        pTable = &pRight->pLeft->token;
+        pColumn = &pRight->pRight->token;
+      }
+      lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr);
+      return 1;
+    }
+
+    /* Resolve function names
+    */
+    case TK_CONST_FUNC:
+    case TK_FUNCTION: {
+      ExprList *pList = pExpr->pList;    /* The argument list */
+      int n = pList ? pList->nExpr : 0;  /* Number of arguments */
+      int no_such_func = 0;       /* True if no such function exists */
+      int wrong_num_args = 0;     /* True if wrong number of arguments */
+      int is_agg = 0;             /* True if is an aggregate function */
+      int i;
+      int auth;                   /* Authorization to use the function */
+      int nId;                    /* Number of characters in function name */
+      const char *zId;            /* The function name. */
+      FuncDef *pDef;              /* Information about the function */
+      int enc = ENC(pParse->db);  /* The database encoding */
+
+      zId = (char*)pExpr->token.z;
+      nId = pExpr->token.n;
+      pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
+      if( pDef==0 ){
+        pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
+        if( pDef==0 ){
+          no_such_func = 1;
+        }else{
+          wrong_num_args = 1;
+        }
+      }else{
+        is_agg = pDef->xFunc==0;
+      }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      if( pDef ){
+        auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
+        if( auth!=SQLITE_OK ){
+          if( auth==SQLITE_DENY ){
+            sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
+                                    pDef->zName);
+            pNC->nErr++;
+          }
+          pExpr->op = TK_NULL;
+          return 1;
+        }
+      }
+#endif
+      if( is_agg && !pNC->allowAgg ){
+        sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
+        pNC->nErr++;
+        is_agg = 0;
+      }else if( no_such_func ){
+        sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
+        pNC->nErr++;
+      }else if( wrong_num_args ){
+        sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
+             nId, zId);
+        pNC->nErr++;
+      }
+      if( is_agg ){
+        pExpr->op = TK_AGG_FUNCTION;
+        pNC->hasAgg = 1;
+      }
+      if( is_agg ) pNC->allowAgg = 0;
+      for(i=0; pNC->nErr==0 && i<n; i++){
+        walkExprTree(pList->a[i].pExpr, nameResolverStep, pNC);
+      }
+      if( is_agg ) pNC->allowAgg = 1;
+      /* FIX ME:  Compute pExpr->affinity based on the expected return
+      ** type of the function 
+      */
+      return is_agg;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:
+#endif
+    case TK_IN: {
+      if( pExpr->pSelect ){
+        int nRef = pNC->nRef;
+#ifndef SQLITE_OMIT_CHECK
+        if( pNC->isCheck ){
+          sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
+        }
+#endif
+        sqlite3SelectResolve(pParse, pExpr->pSelect, pNC);
+        assert( pNC->nRef>=nRef );
+        if( nRef!=pNC->nRef ){
+          ExprSetProperty(pExpr, EP_VarSelect);
+        }
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_CHECK
+    case TK_VARIABLE: {
+      if( pNC->isCheck ){
+        sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
+      }
+      break;
+    }
+#endif
+  }
+  return 0;
+}
+
+/*
+** This routine walks an expression tree and resolves references to
+** table columns.  Nodes of the form ID.ID or ID resolve into an
+** index to the table in the table list and a column offset.  The 
+** Expr.opcode for such nodes is changed to TK_COLUMN.  The Expr.iTable
+** value is changed to the index of the referenced table in pTabList
+** plus the "base" value.  The base value will ultimately become the
+** VDBE cursor number for a cursor that is pointing into the referenced
+** table.  The Expr.iColumn value is changed to the index of the column 
+** of the referenced table.  The Expr.iColumn value for the special
+** ROWID column is -1.  Any INTEGER PRIMARY KEY column is tried as an
+** alias for ROWID.
+**
+** Also resolve function names and check the functions for proper
+** usage.  Make sure all function names are recognized and all functions
+** have the correct number of arguments.  Leave an error message
+** in pParse->zErrMsg if anything is amiss.  Return the number of errors.
+**
+** If the expression contains aggregate functions then set the EP_Agg
+** property on the expression.
+*/
+SQLITE_PRIVATE int sqlite3ExprResolveNames( 
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  Expr *pExpr             /* The expression to be analyzed. */
+){
+  int savedHasAgg;
+
+  if( pExpr==0 ) return 0;
+#if SQLITE_MAX_EXPR_DEPTH>0
+  {
+    int mxDepth = pNC->pParse->db->aLimit[SQLITE_LIMIT_EXPR_DEPTH];
+    if( (pExpr->nHeight+pNC->pParse->nHeight)>mxDepth ){
+      sqlite3ErrorMsg(pNC->pParse, 
+         "Expression tree is too large (maximum depth %d)", mxDepth
+      );
+      return 1;
+    }
+    pNC->pParse->nHeight += pExpr->nHeight;
+  }
+#endif
+  savedHasAgg = pNC->hasAgg;
+  pNC->hasAgg = 0;
+  walkExprTree(pExpr, nameResolverStep, pNC);
+#if SQLITE_MAX_EXPR_DEPTH>0
+  pNC->pParse->nHeight -= pExpr->nHeight;
+#endif
+  if( pNC->nErr>0 ){
+    ExprSetProperty(pExpr, EP_Error);
+  }
+  if( pNC->hasAgg ){
+    ExprSetProperty(pExpr, EP_Agg);
+  }else if( savedHasAgg ){
+    pNC->hasAgg = 1;
+  }
+  return ExprHasProperty(pExpr, EP_Error);
+}
+
+/*
+** A pointer instance of this structure is used to pass information
+** through walkExprTree into codeSubqueryStep().
+*/
+typedef struct QueryCoder QueryCoder;
+struct QueryCoder {
+  Parse *pParse;       /* The parsing context */
+  NameContext *pNC;    /* Namespace of first enclosing query */
+};
+
+#ifdef SQLITE_TEST
+  int sqlite3_enable_in_opt = 1;
+#else
+  #define sqlite3_enable_in_opt 1
+#endif
+
+/*
+** Return true if the IN operator optimization is enabled and
+** the SELECT statement p exists and is of the
+** simple form:
+**
+**     SELECT <column> FROM <table>
+**
+** If this is the case, it may be possible to use an existing table
+** or index instead of generating an epheremal table.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+static int isCandidateForInOpt(Select *p){
+  SrcList *pSrc;
+  ExprList *pEList;
+  Table *pTab;
+  if( !sqlite3_enable_in_opt ) return 0; /* IN optimization must be enabled */
+  if( p==0 ) return 0;                   /* right-hand side of IN is SELECT */
+  if( p->pPrior ) return 0;              /* Not a compound SELECT */
+  if( p->isDistinct ) return 0;          /* No DISTINCT keyword */
+  if( p->isAgg ) return 0;               /* Contains no aggregate functions */
+  if( p->pGroupBy ) return 0;            /* Has no GROUP BY clause */
+  if( p->pLimit ) return 0;              /* Has no LIMIT clause */
+  if( p->pOffset ) return 0;
+  if( p->pWhere ) return 0;              /* Has no WHERE clause */
+  pSrc = p->pSrc;
+  if( pSrc==0 ) return 0;                /* A single table in the FROM clause */
+  if( pSrc->nSrc!=1 ) return 0;
+  if( pSrc->a[0].pSelect ) return 0;     /* FROM clause is not a subquery */
+  pTab = pSrc->a[0].pTab;
+  if( pTab==0 ) return 0;
+  if( pTab->pSelect ) return 0;          /* FROM clause is not a view */
+  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
+  pEList = p->pEList;
+  if( pEList->nExpr!=1 ) return 0;       /* One column in the result set */
+  if( pEList->a[0].pExpr->op!=TK_COLUMN ) return 0; /* Result is a column */
+  return 1;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+/*
+** This function is used by the implementation of the IN (...) operator.
+** It's job is to find or create a b-tree structure that may be used
+** either to test for membership of the (...) set or to iterate through
+** its members, skipping duplicates.
+**
+** The cursor opened on the structure (database table, database index 
+** or ephermal table) is stored in pX->iTable before this function returns.
+** The returned value indicates the structure type, as follows:
+**
+**   IN_INDEX_ROWID - The cursor was opened on a database table.
+**   IN_INDEX_INDEX - The cursor was opened on a database index.
+**   IN_INDEX_EPH -   The cursor was opened on a specially created and
+**                    populated epheremal table.
+**
+** An existing structure may only be used if the SELECT is of the simple
+** form:
+**
+**     SELECT <column> FROM <table>
+**
+** If the mustBeUnique parameter is false, the structure will be used 
+** for fast set membership tests. In this case an epheremal table must 
+** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
+** be found with <column> as its left-most column.
+**
+** If mustBeUnique is true, then the structure will be used to iterate
+** through the set members, skipping any duplicates. In this case an
+** epheremal table must be used unless the selected <column> is guaranteed
+** to be unique - either because it is an INTEGER PRIMARY KEY or it
+** is unique by virtue of a constraint or implicit index.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int mustBeUnique){
+  Select *p;
+  int eType = 0;
+  int iTab = pParse->nTab++;
+
+  /* The follwing if(...) expression is true if the SELECT is of the 
+  ** simple form:
+  **
+  **     SELECT <column> FROM <table>
+  **
+  ** If this is the case, it may be possible to use an existing table
+  ** or index instead of generating an epheremal table.
+  */
+  p = pX->pSelect;
+  if( isCandidateForInOpt(p) ){
+    sqlite3 *db = pParse->db;
+    Index *pIdx;
+    Expr *pExpr = p->pEList->a[0].pExpr;
+    int iCol = pExpr->iColumn;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+
+    /* This function is only called from two places. In both cases the vdbe
+    ** has already been allocated. So assume sqlite3GetVdbe() is always
+    ** successful here.
+    */
+    assert(v);
+    if( iCol<0 ){
+      int iMem = ++pParse->nMem;
+      int iAddr;
+      Table *pTab = p->pSrc->a[0].pTab;
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      sqlite3VdbeUsesBtree(v, iDb);
+
+      iAddr = sqlite3VdbeAddOp1(v, OP_If, iMem);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iMem);
+
+      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+      eType = IN_INDEX_ROWID;
+
+      sqlite3VdbeJumpHere(v, iAddr);
+    }else{
+      /* The collation sequence used by the comparison. If an index is to 
+      ** be used in place of a temp-table, it must be ordered according
+      ** to this collation sequence.
+      */
+      CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pExpr);
+
+      /* Check that the affinity that will be used to perform the 
+      ** comparison is the same as the affinity of the column. If
+      ** it is not, it is not possible to use any index.
+      */
+      Table *pTab = p->pSrc->a[0].pTab;
+      char aff = comparisonAffinity(pX);
+      int affinity_ok = (pTab->aCol[iCol].affinity==aff||aff==SQLITE_AFF_NONE);
+
+      for(pIdx=pTab->pIndex; pIdx && eType==0 && affinity_ok; pIdx=pIdx->pNext){
+        if( (pIdx->aiColumn[0]==iCol)
+         && (pReq==sqlite3FindCollSeq(db, ENC(db), pIdx->azColl[0], -1, 0))
+         && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
+        ){
+          int iDb;
+          int iMem = ++pParse->nMem;
+          int iAddr;
+          char *pKey;
+  
+          pKey = (char *)sqlite3IndexKeyinfo(pParse, pIdx);
+          iDb = sqlite3SchemaToIndex(db, pIdx->pSchema);
+          sqlite3VdbeUsesBtree(v, iDb);
+
+          iAddr = sqlite3VdbeAddOp1(v, OP_If, iMem);
+          sqlite3VdbeAddOp2(v, OP_Integer, 1, iMem);
+  
+          sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pIdx->nColumn);
+          sqlite3VdbeAddOp4(v, OP_OpenRead, iTab, pIdx->tnum, iDb,
+                               pKey,P4_KEYINFO_HANDOFF);
+          VdbeComment((v, "%s", pIdx->zName));
+          eType = IN_INDEX_INDEX;
+
+          sqlite3VdbeJumpHere(v, iAddr);
+        }
+      }
+    }
+  }
+
+  if( eType==0 ){
+    sqlite3CodeSubselect(pParse, pX);
+    eType = IN_INDEX_EPH;
+  }else{
+    pX->iTable = iTab;
+  }
+  return eType;
+}
+#endif
+
+/*
+** Generate code for scalar subqueries used as an expression
+** and IN operators.  Examples:
+**
+**     (SELECT a FROM b)          -- subquery
+**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
+**     x IN (4,5,11)              -- IN operator with list on right-hand side
+**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
+**
+** The pExpr parameter describes the expression that contains the IN
+** operator or subquery.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
+  int testAddr = 0;                       /* One-time test address */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+
+
+  /* This code must be run in its entirety every time it is encountered
+  ** if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can run this code just once
+  ** save the results, and reuse the same result on subsequent invocations.
+  */
+  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
+    int mem = ++pParse->nMem;
+    sqlite3VdbeAddOp1(v, OP_If, mem);
+    testAddr = sqlite3VdbeAddOp2(v, OP_Integer, 1, mem);
+    assert( testAddr>0 || pParse->db->mallocFailed );
+  }
+
+  switch( pExpr->op ){
+    case TK_IN: {
+      char affinity;
+      KeyInfo keyInfo;
+      int addr;        /* Address of OP_OpenEphemeral instruction */
+
+      affinity = sqlite3ExprAffinity(pExpr->pLeft);
+
+      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
+      ** expression it is handled the same way. A virtual table is 
+      ** filled with single-field index keys representing the results
+      ** from the SELECT or the <exprlist>.
+      **
+      ** If the 'x' expression is a column value, or the SELECT...
+      ** statement returns a column value, then the affinity of that
+      ** column is used to build the index keys. If both 'x' and the
+      ** SELECT... statement are columns, then numeric affinity is used
+      ** if either column has NUMERIC or INTEGER affinity. If neither
+      ** 'x' nor the SELECT... statement are columns, then numeric affinity
+      ** is used.
+      */
+      pExpr->iTable = pParse->nTab++;
+      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, 1);
+      memset(&keyInfo, 0, sizeof(keyInfo));
+      keyInfo.nField = 1;
+
+      if( pExpr->pSelect ){
+        /* Case 1:     expr IN (SELECT ...)
+        **
+        ** Generate code to write the results of the select into the temporary
+        ** table allocated and opened above.
+        */
+        SelectDest dest;
+        ExprList *pEList;
+
+        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
+        dest.affinity = (int)affinity;
+        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
+        if( sqlite3Select(pParse, pExpr->pSelect, &dest, 0, 0, 0, 0) ){
+          return;
+        }
+        pEList = pExpr->pSelect->pEList;
+        if( pEList && pEList->nExpr>0 ){ 
+          keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
+              pEList->a[0].pExpr);
+        }
+      }else if( pExpr->pList ){
+        /* Case 2:     expr IN (exprlist)
+        **
+        ** For each expression, build an index key from the evaluation and
+        ** store it in the temporary table. If <expr> is a column, then use
+        ** that columns affinity when building index keys. If <expr> is not
+        ** a column, use numeric affinity.
+        */
+        int i;
+        ExprList *pList = pExpr->pList;
+        struct ExprList_item *pItem;
+        int r1, r2;
+
+        if( !affinity ){
+          affinity = SQLITE_AFF_NONE;
+        }
+        keyInfo.aColl[0] = pExpr->pLeft->pColl;
+
+        /* Loop through each expression in <exprlist>. */
+        r1 = sqlite3GetTempReg(pParse);
+        r2 = sqlite3GetTempReg(pParse);
+        for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
+          Expr *pE2 = pItem->pExpr;
+
+          /* If the expression is not constant then we will need to
+          ** disable the test that was generated above that makes sure
+          ** this code only executes once.  Because for a non-constant
+          ** expression we need to rerun this code each time.
+          */
+          if( testAddr && !sqlite3ExprIsConstant(pE2) ){
+            sqlite3VdbeChangeToNoop(v, testAddr-1, 2);
+            testAddr = 0;
+          }
+
+          /* Evaluate the expression and insert it into the temp table */
+          pParse->disableColCache++;
+          sqlite3ExprCode(pParse, pE2, r1);
+          assert( pParse->disableColCache>0 );
+          pParse->disableColCache--;
+          sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
+          sqlite3ExprCacheAffinityChange(pParse, r1, 1);
+          sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
+        }
+        sqlite3ReleaseTempReg(pParse, r1);
+        sqlite3ReleaseTempReg(pParse, r2);
+      }
+      sqlite3VdbeChangeP4(v, addr, (void *)&keyInfo, P4_KEYINFO);
+      break;
+    }
+
+    case TK_EXISTS:
+    case TK_SELECT: {
+      /* This has to be a scalar SELECT.  Generate code to put the
+      ** value of this select in a memory cell and record the number
+      ** of the memory cell in iColumn.
+      */
+      static const Token one = { (u8*)"1", 0, 1 };
+      Select *pSel;
+      SelectDest dest;
+
+      pSel = pExpr->pSelect;
+      sqlite3SelectDestInit(&dest, 0, ++pParse->nMem);
+      if( pExpr->op==TK_SELECT ){
+        dest.eDest = SRT_Mem;
+        sqlite3VdbeAddOp2(v, OP_Null, 0, dest.iParm);
+        VdbeComment((v, "Init subquery result"));
+      }else{
+        dest.eDest = SRT_Exists;
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
+        VdbeComment((v, "Init EXISTS result"));
+      }
+      sqlite3ExprDelete(pSel->pLimit);
+      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
+      if( sqlite3Select(pParse, pSel, &dest, 0, 0, 0, 0) ){
+        return;
+      }
+      pExpr->iColumn = dest.iParm;
+      break;
+    }
+  }
+
+  if( testAddr ){
+    sqlite3VdbeJumpHere(v, testAddr-1);
+  }
+
+  return;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+/*
+** Duplicate an 8-byte value
+*/
+static char *dup8bytes(Vdbe *v, const char *in){
+  char *out = sqlite3DbMallocRaw(sqlite3VdbeDb(v), 8);
+  if( out ){
+    memcpy(out, in, 8);
+  }
+  return out;
+}
+
+/*
+** Generate an instruction that will put the floating point
+** value described by z[0..n-1] into register iMem.
+**
+** The z[] string will probably not be zero-terminated.  But the 
+** z[n] character is guaranteed to be something that does not look
+** like the continuation of the number.
+*/
+static void codeReal(Vdbe *v, const char *z, int n, int negateFlag, int iMem){
+  assert( z || v==0 || sqlite3VdbeDb(v)->mallocFailed );
+  if( z ){
+    double value;
+    char *zV;
+    assert( !isdigit(z[n]) );
+    sqlite3AtoF(z, &value);
+    if( sqlite3IsNaN(value) ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, iMem);
+    }else{
+      if( negateFlag ) value = -value;
+      zV = dup8bytes(v, (char*)&value);
+      sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
+    }
+  }
+}
+
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] into register iMem.
+**
+** The z[] string will probably not be zero-terminated.  But the 
+** z[n] character is guaranteed to be something that does not look
+** like the continuation of the number.
+*/
+static void codeInteger(Vdbe *v, const char *z, int n, int negFlag, int iMem){
+  assert( z || v==0 || sqlite3VdbeDb(v)->mallocFailed );
+  if( z ){
+    int i;
+    assert( !isdigit(z[n]) );
+    if( sqlite3GetInt32(z, &i) ){
+      if( negFlag ) i = -i;
+      sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
+    }else if( sqlite3FitsIn64Bits(z, negFlag) ){
+      i64 value;
+      char *zV;
+      sqlite3Atoi64(z, &value);
+      if( negFlag ) value = -value;
+      zV = dup8bytes(v, (char*)&value);
+      sqlite3VdbeAddOp4(v, OP_Int64, 0, iMem, 0, zV, P4_INT64);
+    }else{
+      codeReal(v, z, n, negFlag, iMem);
+    }
+  }
+}
+
+
+/*
+** Generate code that will extract the iColumn-th column from
+** table pTab and store the column value in a register.  An effort
+** is made to store the column value in register iReg, but this is
+** not guaranteed.  The location of the column value is returned.
+**
+** There must be an open cursor to pTab in iTable when this routine
+** is called.  If iColumn<0 then code is generated that extracts the rowid.
+**
+** This routine might attempt to reuse the value of the column that
+** has already been loaded into a register.  The value will always
+** be used if it has not undergone any affinity changes.  But if
+** an affinity change has occurred, then the cached value will only be
+** used if allowAffChng is true.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg,        /* Store results here */
+  int allowAffChng /* True if prior affinity changes are OK */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct yColCache *p;
+
+  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+    if( p->iTable==iTable && p->iColumn==iColumn
+           && (!p->affChange || allowAffChng) ){
+#if 0
+      sqlite3VdbeAddOp0(v, OP_Noop);
+      VdbeComment((v, "OPT: tab%d.col%d -> r%d", iTable, iColumn, p->iReg));
+#endif
+      return p->iReg;
+    }
+  }  
+  assert( v!=0 );
+  if( iColumn<0 ){
+    int op = (pTab && IsVirtual(pTab)) ? OP_VRowid : OP_Rowid;
+    sqlite3VdbeAddOp2(v, op, iTable, iReg);
+  }else if( pTab==0 ){
+    sqlite3VdbeAddOp3(v, OP_Column, iTable, iColumn, iReg);
+  }else{
+    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
+    sqlite3VdbeAddOp3(v, op, iTable, iColumn, iReg);
+    sqlite3ColumnDefault(v, pTab, iColumn);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    if( pTab->aCol[iColumn].affinity==SQLITE_AFF_REAL ){
+      sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
+    }
+#endif
+  }
+  if( pParse->disableColCache==0 ){
+    i = pParse->iColCache;
+    p = &pParse->aColCache[i];
+    p->iTable = iTable;
+    p->iColumn = iColumn;
+    p->iReg = iReg;
+    p->affChange = 0;
+    i++;
+    if( i>=ArraySize(pParse->aColCache) ) i = 0;
+    if( i>pParse->nColCache ) pParse->nColCache = i;
+    pParse->iColCache = i;
+  }
+  return iReg;
+}
+
+/*
+** Clear all column cache entries associated with the vdbe
+** cursor with cursor number iTable.
+*/
+SQLITE_PRIVATE void sqlite3ExprClearColumnCache(Parse *pParse, int iTable){
+  if( iTable<0 ){
+    pParse->nColCache = 0;
+    pParse->iColCache = 0;
+  }else{
+    int i;
+    for(i=0; i<pParse->nColCache; i++){
+      if( pParse->aColCache[i].iTable==iTable ){
+        testcase( i==pParse->nColCache-1 );
+        pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
+        pParse->iColCache = pParse->nColCache;
+      }
+    }
+  }
+}
+
+/*
+** Record the fact that an affinity change has occurred on iCount
+** registers starting with iStart.
+*/
+SQLITE_PRIVATE void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
+  int iEnd = iStart + iCount - 1;
+  int i;
+  for(i=0; i<pParse->nColCache; i++){
+    int r = pParse->aColCache[i].iReg;
+    if( r>=iStart && r<=iEnd ){
+      pParse->aColCache[i].affChange = 1;
+    }
+  }
+}
+
+/*
+** Generate code to moves content from one register to another.
+** Keep the column cache up-to-date.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo){
+  int i;
+  if( iFrom==iTo ) return;
+  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Move, iFrom, iTo);
+  for(i=0; i<pParse->nColCache; i++){
+    if( pParse->aColCache[i].iReg==iFrom ){
+      pParse->aColCache[i].iReg = iTo;
+    }
+  }
+}
+
+/*
+** Return true if any register in the range iFrom..iTo (inclusive)
+** is used as part of the column cache.
+*/
+static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
+  int i;
+  for(i=0; i<pParse->nColCache; i++){
+    int r = pParse->aColCache[i].iReg;
+    if( r>=iFrom && r<=iTo ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Theres is a value in register iCurrent.  We ultimately want
+** the value to be in register iTarget.  It might be that
+** iCurrent and iTarget are the same register.
+**
+** We are going to modify the value, so we need to make sure it
+** is not a cached register.  If iCurrent is a cached register,
+** then try to move the value over to iTarget.  If iTarget is a
+** cached register, then clear the corresponding cache line.
+**
+** Return the register that the value ends up in.
+*/
+SQLITE_PRIVATE int sqlite3ExprWritableRegister(Parse *pParse, int iCurrent, int iTarget){
+  int i;
+  assert( pParse->pVdbe!=0 );
+  if( !usedAsColumnCache(pParse, iCurrent, iCurrent) ){
+    return iCurrent;
+  }
+  if( iCurrent!=iTarget ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, iCurrent, iTarget);
+  }
+  for(i=0; i<pParse->nColCache; i++){
+    if( pParse->aColCache[i].iReg==iTarget ){
+      pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
+      pParse->iColCache = pParse->nColCache;
+    }
+  }
+  return iTarget;
+}
+
+/*
+** If the last instruction coded is an ephemeral copy of any of
+** the registers in the nReg registers beginning with iReg, then
+** convert the last instruction from OP_SCopy to OP_Copy.
+*/
+SQLITE_PRIVATE void sqlite3ExprHardCopy(Parse *pParse, int iReg, int nReg){
+  int addr;
+  VdbeOp *pOp;
+  Vdbe *v;
+
+  v = pParse->pVdbe;
+  addr = sqlite3VdbeCurrentAddr(v);
+  pOp = sqlite3VdbeGetOp(v, addr-1);
+  assert( pOp || pParse->db->mallocFailed );
+  if( pOp && pOp->opcode==OP_SCopy && pOp->p1>=iReg && pOp->p1<iReg+nReg ){
+    pOp->opcode = OP_Copy;
+  }
+}
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression.  Attempt to store the results in register "target".
+** Return the register where results are stored.
+**
+** With this routine, there is no guaranteed that results will
+** be stored in target.  The result might be stored in some other
+** register if it is convenient to do so.  The calling function
+** must check the return code and move the results to the desired
+** register.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
+  int op;                   /* The opcode being coded */
+  int inReg = target;       /* Results stored in register inReg */
+  int regFree1 = 0;         /* If non-zero free this temporary register */
+  int regFree2 = 0;         /* If non-zero free this temporary register */
+  int r1, r2, r3, r4;       /* Various register numbers */
+
+  assert( v!=0 || pParse->db->mallocFailed );
+  assert( target>0 && target<=pParse->nMem );
+  if( v==0 ) return 0;
+
+  if( pExpr==0 ){
+    op = TK_NULL;
+  }else{
+    op = pExpr->op;
+  }
+  switch( op ){
+    case TK_AGG_COLUMN: {
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      struct AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
+      if( !pAggInfo->directMode ){
+        assert( pCol->iMem>0 );
+        inReg = pCol->iMem;
+        break;
+      }else if( pAggInfo->useSortingIdx ){
+        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdx,
+                              pCol->iSorterColumn, target);
+        break;
+      }
+      /* Otherwise, fall thru into the TK_COLUMN case */
+    }
+    case TK_COLUMN: {
+      if( pExpr->iTable<0 ){
+        /* This only happens when coding check constraints */
+        assert( pParse->ckBase>0 );
+        inReg = pExpr->iColumn + pParse->ckBase;
+      }else{
+        testcase( (pExpr->flags & EP_AnyAff)!=0 );
+        inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
+                                 pExpr->iColumn, pExpr->iTable, target,
+                                 pExpr->flags & EP_AnyAff);
+      }
+      break;
+    }
+    case TK_INTEGER: {
+      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
+      break;
+    }
+    case TK_FLOAT: {
+      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
+      break;
+    }
+    case TK_STRING: {
+      sqlite3DequoteExpr(pParse->db, pExpr);
+      sqlite3VdbeAddOp4(v,OP_String8, 0, target, 0,
+                        (char*)pExpr->token.z, pExpr->token.n);
+      break;
+    }
+    case TK_NULL: {
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      break;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      int n;
+      const char *z;
+      char *zBlob;
+      assert( pExpr->token.n>=3 );
+      assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
+      assert( pExpr->token.z[1]=='\'' );
+      assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
+      n = pExpr->token.n - 3;
+      z = (char*)pExpr->token.z + 2;
+      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
+      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
+      break;
+    }
+#endif
+    case TK_VARIABLE: {
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iTable, target);
+      if( pExpr->token.n>1 ){
+        sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
+      }
+      break;
+    }
+    case TK_REGISTER: {
+      inReg = pExpr->iTable;
+      break;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      int aff, to_op;
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      aff = sqlite3AffinityType(&pExpr->token);
+      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
+      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
+      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
+      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
+      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
+      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
+      testcase( to_op==OP_ToText );
+      testcase( to_op==OP_ToBlob );
+      testcase( to_op==OP_ToNumeric );
+      testcase( to_op==OP_ToInt );
+      testcase( to_op==OP_ToReal );
+      sqlite3VdbeAddOp1(v, to_op, inReg);
+      testcase( usedAsColumnCache(pParse, inReg, inReg) );
+      sqlite3ExprCacheAffinityChange(pParse, inReg, 1);
+      break;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
+      testcase( op==TK_LT );
+      testcase( op==TK_LE );
+      testcase( op==TK_GT );
+      testcase( op==TK_GE );
+      testcase( op==TK_EQ );
+      testcase( op==TK_NE );
+      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
+                                  pExpr->pRight, &r2, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, inReg, SQLITE_STOREP2);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_AND:
+    case TK_OR:
+    case TK_PLUS:
+    case TK_STAR:
+    case TK_MINUS:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_BITOR:
+    case TK_SLASH:
+    case TK_LSHIFT:
+    case TK_RSHIFT: 
+    case TK_CONCAT: {
+      assert( TK_AND==OP_And );
+      assert( TK_OR==OP_Or );
+      assert( TK_PLUS==OP_Add );
+      assert( TK_MINUS==OP_Subtract );
+      assert( TK_REM==OP_Remainder );
+      assert( TK_BITAND==OP_BitAnd );
+      assert( TK_BITOR==OP_BitOr );
+      assert( TK_SLASH==OP_Divide );
+      assert( TK_LSHIFT==OP_ShiftLeft );
+      assert( TK_RSHIFT==OP_ShiftRight );
+      assert( TK_CONCAT==OP_Concat );
+      testcase( op==TK_AND );
+      testcase( op==TK_OR );
+      testcase( op==TK_PLUS );
+      testcase( op==TK_MINUS );
+      testcase( op==TK_REM );
+      testcase( op==TK_BITAND );
+      testcase( op==TK_BITOR );
+      testcase( op==TK_SLASH );
+      testcase( op==TK_LSHIFT );
+      testcase( op==TK_RSHIFT );
+      testcase( op==TK_CONCAT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      sqlite3VdbeAddOp3(v, op, r2, r1, target);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_UMINUS: {
+      Expr *pLeft = pExpr->pLeft;
+      assert( pLeft );
+      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
+        Token *p = &pLeft->token;
+        if( pLeft->op==TK_FLOAT ){
+          codeReal(v, (char*)p->z, p->n, 1, target);
+        }else{
+          codeInteger(v, (char*)p->z, p->n, 1, target);
+        }
+      }else{
+        regFree1 = r1 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree2);
+        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
+        testcase( regFree2==0 );
+      }
+      inReg = target;
+      break;
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );
+      assert( TK_NOT==OP_Not );
+      testcase( op==TK_BITNOT );
+      testcase( op==TK_NOT );
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      testcase( inReg==target );
+      testcase( usedAsColumnCache(pParse, inReg, inReg) );
+      inReg = sqlite3ExprWritableRegister(pParse, inReg, target);
+      sqlite3VdbeAddOp1(v, op, inReg);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      int addr;
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
+      testcase( op==TK_ISNULL );
+      testcase( op==TK_NOTNULL );
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      testcase( regFree1==0 );
+      addr = sqlite3VdbeAddOp1(v, op, r1);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
+      sqlite3VdbeJumpHere(v, addr);
+      break;
+    }
+    case TK_AGG_FUNCTION: {
+      AggInfo *pInfo = pExpr->pAggInfo;
+      if( pInfo==0 ){
+        sqlite3ErrorMsg(pParse, "misuse of aggregate: %T",
+            &pExpr->span);
+      }else{
+        inReg = pInfo->aFunc[pExpr->iAgg].iMem;
+      }
+      break;
+    }
+    case TK_CONST_FUNC:
+    case TK_FUNCTION: {
+      ExprList *pList = pExpr->pList;
+      int nExpr = pList ? pList->nExpr : 0;
+      FuncDef *pDef;
+      int nId;
+      const char *zId;
+      int constMask = 0;
+      int i;
+      sqlite3 *db = pParse->db;
+      u8 enc = ENC(db);
+      CollSeq *pColl = 0;
+
+      testcase( op==TK_CONST_FUNC );
+      testcase( op==TK_FUNCTION );
+      zId = (char*)pExpr->token.z;
+      nId = pExpr->token.n;
+      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
+      assert( pDef!=0 );
+      if( pList ){
+        nExpr = pList->nExpr;
+        r1 = sqlite3GetTempRange(pParse, nExpr);
+        sqlite3ExprCodeExprList(pParse, pList, r1, 1);
+      }else{
+        nExpr = r1 = 0;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Possibly overload the function if the first argument is
+      ** a virtual table column.
+      **
+      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
+      ** second argument, not the first, as the argument to test to
+      ** see if it is a column in a virtual table.  This is done because
+      ** the left operand of infix functions (the operand we want to
+      ** control overloading) ends up as the second argument to the
+      ** function.  The expression "A glob B" is equivalent to 
+      ** "glob(B,A).  We want to use the A in "A glob B" to test
+      ** for function overloading.  But we use the B term in "glob(B,A)".
+      */
+      if( nExpr>=2 && (pExpr->flags & EP_InfixFunc) ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[1].pExpr);
+      }else if( nExpr>0 ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[0].pExpr);
+      }
+#endif
+      for(i=0; i<nExpr && i<32; i++){
+        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
+          constMask |= (1<<i);
+        }
+        if( pDef->needCollSeq && !pColl ){
+          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
+        }
+      }
+      if( pDef->needCollSeq ){
+        if( !pColl ) pColl = pParse->db->pDfltColl; 
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
+                        (char*)pDef, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, nExpr);
+      if( nExpr ){
+        sqlite3ReleaseTempRange(pParse, r1, nExpr);
+      }
+      sqlite3ExprCacheAffinityChange(pParse, r1, nExpr);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS:
+    case TK_SELECT: {
+      testcase( op==TK_EXISTS );
+      testcase( op==TK_SELECT );
+      if( pExpr->iColumn==0 ){
+        sqlite3CodeSubselect(pParse, pExpr);
+      }
+      inReg = pExpr->iColumn;
+      break;
+    }
+    case TK_IN: {
+      int j1, j2, j3, j4, j5;
+      char affinity;
+      int eType;
+
+      eType = sqlite3FindInIndex(pParse, pExpr, 0);
+
+      /* Figure out the affinity to use to create a key from the results
+      ** of the expression. affinityStr stores a static string suitable for
+      ** P4 of OP_MakeRecord.
+      */
+      affinity = comparisonAffinity(pExpr);
+
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+
+      /* Code the <expr> from "<expr> IN (...)". The temporary table
+      ** pExpr->iTable contains the values that make up the (...) set.
+      */
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      testcase( regFree1==0 );
+      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, r1);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      j2  = sqlite3VdbeAddOp0(v, OP_Goto);
+      sqlite3VdbeJumpHere(v, j1);
+      if( eType==IN_INDEX_ROWID ){
+        j3 = sqlite3VdbeAddOp1(v, OP_MustBeInt, r1);
+        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, r1);
+        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
+        sqlite3VdbeJumpHere(v, j3);
+        sqlite3VdbeJumpHere(v, j4);
+      }else{
+        r2 = regFree2 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
+        sqlite3ExprCacheAffinityChange(pParse, r1, 1);
+        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);
+      }
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
+      sqlite3VdbeJumpHere(v, j2);
+      sqlite3VdbeJumpHere(v, j5);
+      break;
+    }
+#endif
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      Expr *pLeft = pExpr->pLeft;
+      struct ExprList_item *pLItem = pExpr->pList->a;
+      Expr *pRight = pLItem->pExpr;
+
+      codeCompareOperands(pParse, pLeft, &r1, &regFree1,
+                                  pRight, &r2, &regFree2);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      r3 = sqlite3GetTempReg(pParse);
+      r4 = sqlite3GetTempReg(pParse);
+      codeCompare(pParse, pLeft, pRight, OP_Ge,
+                  r1, r2, r3, SQLITE_STOREP2);
+      pLItem++;
+      pRight = pLItem->pExpr;
+      sqlite3ReleaseTempReg(pParse, regFree2);
+      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
+      testcase( regFree2==0 );
+      codeCompare(pParse, pLeft, pRight, OP_Le, r1, r2, r4, SQLITE_STOREP2);
+      sqlite3VdbeAddOp3(v, OP_And, r3, r4, target);
+      sqlite3ReleaseTempReg(pParse, r3);
+      sqlite3ReleaseTempReg(pParse, r4);
+      break;
+    }
+    case TK_UPLUS: {
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      break;
+    }
+
+    /*
+    ** Form A:
+    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form B:
+    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form A is can be transformed into the equivalent form B as follows:
+    **   CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
+    **        WHEN x=eN THEN rN ELSE y END
+    **
+    ** X (if it exists) is in pExpr->pLeft.
+    ** Y is in pExpr->pRight.  The Y is also optional.  If there is no
+    ** ELSE clause and no other term matches, then the result of the
+    ** exprssion is NULL.
+    ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
+    **
+    ** The result of the expression is the Ri for the first matching Ei,
+    ** or if there is no matching Ei, the ELSE term Y, or if there is
+    ** no ELSE term, NULL.
+    */
+    case TK_CASE: {
+      int endLabel;                     /* GOTO label for end of CASE stmt */
+      int nextCase;                     /* GOTO label for next WHEN clause */
+      int nExpr;                        /* 2x number of WHEN terms */
+      int i;                            /* Loop counter */
+      ExprList *pEList;                 /* List of WHEN terms */
+      struct ExprList_item *aListelem;  /* Array of WHEN terms */
+      Expr opCompare;                   /* The X==Ei expression */
+      Expr cacheX;                      /* Cached expression X */
+      Expr *pX;                         /* The X expression */
+      Expr *pTest;                      /* X==Ei (form A) or just Ei (form B) */
+
+      assert(pExpr->pList);
+      assert((pExpr->pList->nExpr % 2) == 0);
+      assert(pExpr->pList->nExpr > 0);
+      pEList = pExpr->pList;
+      aListelem = pEList->a;
+      nExpr = pEList->nExpr;
+      endLabel = sqlite3VdbeMakeLabel(v);
+      if( (pX = pExpr->pLeft)!=0 ){
+        cacheX = *pX;
+        testcase( pX->op==TK_COLUMN || pX->op==TK_REGISTER );
+        cacheX.iTable = sqlite3ExprCodeTemp(pParse, pX, &regFree1);
+        testcase( regFree1==0 );
+        cacheX.op = TK_REGISTER;
+        cacheX.iColumn = 0;
+        opCompare.op = TK_EQ;
+        opCompare.pLeft = &cacheX;
+        pTest = &opCompare;
+      }
+      pParse->disableColCache++;
+      for(i=0; i<nExpr; i=i+2){
+        if( pX ){
+          opCompare.pRight = aListelem[i].pExpr;
+        }else{
+          pTest = aListelem[i].pExpr;
+        }
+        nextCase = sqlite3VdbeMakeLabel(v);
+        testcase( pTest->op==TK_COLUMN || pTest->op==TK_REGISTER );
+        sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
+        testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
+        testcase( aListelem[i+1].pExpr->op==TK_REGISTER );
+        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, endLabel);
+        sqlite3VdbeResolveLabel(v, nextCase);
+      }
+      if( pExpr->pRight ){
+        sqlite3ExprCode(pParse, pExpr->pRight, target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      sqlite3VdbeResolveLabel(v, endLabel);
+      assert( pParse->disableColCache>0 );
+      pParse->disableColCache--;
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      if( !pParse->trigStack ){
+        sqlite3ErrorMsg(pParse,
+                       "RAISE() may only be used within a trigger-program");
+        return 0;
+      }
+      if( pExpr->iColumn!=OE_Ignore ){
+         assert( pExpr->iColumn==OE_Rollback ||
+                 pExpr->iColumn == OE_Abort ||
+                 pExpr->iColumn == OE_Fail );
+         sqlite3DequoteExpr(pParse->db, pExpr);
+         sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn, 0,
+                        (char*)pExpr->token.z, pExpr->token.n);
+      } else {
+         assert( pExpr->iColumn == OE_Ignore );
+         sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
+         sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
+         VdbeComment((v, "raise(IGNORE)"));
+      }
+      break;
+    }
+#endif
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+  return inReg;
+}
+
+/*
+** Generate code to evaluate an expression and store the results
+** into a register.  Return the register number where the results
+** are stored.
+**
+** If the register is a temporary register that can be deallocated,
+** then write its number into *pReg.  If the result register is not
+** a temporary, then set *pReg to zero.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
+  int r1 = sqlite3GetTempReg(pParse);
+  int r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+  if( r2==r1 ){
+    *pReg = r1;
+  }else{
+    sqlite3ReleaseTempReg(pParse, r1);
+    *pReg = 0;
+  }
+  return r2;
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.
+*/
+SQLITE_PRIVATE int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
+  int inReg;
+
+  assert( target>0 && target<=pParse->nMem );
+  inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+  assert( pParse->pVdbe || pParse->db->mallocFailed );
+  if( inReg!=target && pParse->pVdbe ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+  }
+  return target;
+}
+
+/*
+** Generate code that evalutes the given expression and puts the result
+** in register target.
+**
+** Also make a copy of the expression results into another "cache" register
+** and modify the expression so that the next time it is evaluated,
+** the result is a copy of the cache register.
+**
+** This routine is used for expressions that are used multiple 
+** times.  They are evaluated once and the results of the expression
+** are reused.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;
+  int inReg;
+  inReg = sqlite3ExprCode(pParse, pExpr, target);
+  assert( target>0 );
+  if( pExpr->op!=TK_REGISTER ){  
+    int iMem;
+    iMem = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Copy, inReg, iMem);
+    pExpr->iTable = iMem;
+    pExpr->iColumn = pExpr->op;
+    pExpr->op = TK_REGISTER;
+  }
+  return inReg;
+}
+
+/*
+** Return TRUE if pExpr is an constant expression that is appropriate
+** for factoring out of a loop.  Appropriate expressions are:
+**
+**    *  Any expression that evaluates to two or more opcodes.
+**
+**    *  Any OP_Integer, OP_Real, OP_String, OP_Blob, OP_Null, 
+**       or OP_Variable that does not need to be placed in a 
+**       specific register.
+**
+** There is no point in factoring out single-instruction constant
+** expressions that need to be placed in a particular register.  
+** We could factor them out, but then we would end up adding an
+** OP_SCopy instruction to move the value into the correct register
+** later.  We might as well just use the original instruction and
+** avoid the OP_SCopy.
+*/
+static int isAppropriateForFactoring(Expr *p){
+  if( !sqlite3ExprIsConstantNotJoin(p) ){
+    return 0;  /* Only constant expressions are appropriate for factoring */
+  }
+  if( (p->flags & EP_FixedDest)==0 ){
+    return 1;  /* Any constant without a fixed destination is appropriate */
+  }
+  while( p->op==TK_UPLUS ) p = p->pLeft;
+  switch( p->op ){
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB:
+#endif
+    case TK_VARIABLE:
+    case TK_INTEGER:
+    case TK_FLOAT:
+    case TK_NULL:
+    case TK_STRING: {
+      testcase( p->op==TK_BLOB );
+      testcase( p->op==TK_VARIABLE );
+      testcase( p->op==TK_INTEGER );
+      testcase( p->op==TK_FLOAT );
+      testcase( p->op==TK_NULL );
+      testcase( p->op==TK_STRING );
+      /* Single-instruction constants with a fixed destination are
+      ** better done in-line.  If we factor them, they will just end
+      ** up generating an OP_SCopy to move the value to the destination
+      ** register. */
+      return 0;
+    }
+    case TK_UMINUS: {
+       if( p->pLeft->op==TK_FLOAT || p->pLeft->op==TK_INTEGER ){
+         return 0;
+       }
+       break;
+    }
+    default: {
+      break;
+    }
+  }
+  return 1;
+}
+
+/*
+** If pExpr is a constant expression that is appropriate for
+** factoring out of a loop, then evaluate the expression
+** into a register and convert the expression into a TK_REGISTER
+** expression.
+*/
+static int evalConstExpr(void *pArg, Expr *pExpr){
+  Parse *pParse = (Parse*)pArg;
+  switch( pExpr->op ){
+    case TK_REGISTER: {
+      return 1;
+    }
+    case TK_FUNCTION:
+    case TK_AGG_FUNCTION:
+    case TK_CONST_FUNC: {
+      /* The arguments to a function have a fixed destination.
+      ** Mark them this way to avoid generated unneeded OP_SCopy
+      ** instructions. 
+      */
+      ExprList *pList = pExpr->pList;
+      if( pList ){
+        int i = pList->nExpr;
+        struct ExprList_item *pItem = pList->a;
+        for(; i>0; i--, pItem++){
+          if( pItem->pExpr ) pItem->pExpr->flags |= EP_FixedDest;
+        }
+      }
+      break;
+    }
+  }
+  if( isAppropriateForFactoring(pExpr) ){
+    int r1 = ++pParse->nMem;
+    int r2;
+    r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+    if( r1!=r2 ) sqlite3ReleaseTempReg(pParse, r1);
+    pExpr->iColumn = pExpr->op;
+    pExpr->op = TK_REGISTER;
+    pExpr->iTable = r2;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Preevaluate constant subexpressions within pExpr and store the
+** results in registers.  Modify pExpr so that the constant subexpresions
+** are TK_REGISTER opcodes that refer to the precomputed values.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeConstants(Parse *pParse, Expr *pExpr){
+   walkExprTree(pExpr, evalConstExpr, pParse);
+}
+
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list into a sequence of registers beginning at target.
+**
+** Return the number of elements evaluated.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(
+  Parse *pParse,     /* Parsing context */
+  ExprList *pList,   /* The expression list to be coded */
+  int target,        /* Where to write results */
+  int doHardCopy     /* Call sqlite3ExprHardCopy on each element if true */
+){
+  struct ExprList_item *pItem;
+  int i, n;
+  assert( pList!=0 || pParse->db->mallocFailed );
+  if( pList==0 ){
+    return 0;
+  }
+  assert( target>0 );
+  n = pList->nExpr;
+  for(pItem=pList->a, i=0; i<n; i++, pItem++){
+    sqlite3ExprCode(pParse, pItem->pExpr, target+i);
+    if( doHardCopy ) sqlite3ExprHardCopy(pParse, target, n);
+  }
+  return n;
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is true but execution
+** continues straight thru if the expression is false.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( v==0 || pExpr==0 ) return;
+  op = pExpr->op;
+  switch( op ){
+    case TK_AND: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      testcase( jumpIfNull==0 );
+      testcase( pParse->disableColCache==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
+      pParse->disableColCache++;
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      assert( pParse->disableColCache>0 );
+      pParse->disableColCache--;
+      sqlite3VdbeResolveLabel(v, d2);
+      break;
+    }
+    case TK_OR: {
+      testcase( jumpIfNull==0 );
+      testcase( pParse->disableColCache==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      pParse->disableColCache++;
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      assert( pParse->disableColCache>0 );
+      pParse->disableColCache--;
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
+      testcase( op==TK_LT );
+      testcase( op==TK_LE );
+      testcase( op==TK_GT );
+      testcase( op==TK_GE );
+      testcase( op==TK_EQ );
+      testcase( op==TK_NE );
+      testcase( jumpIfNull==0 );
+      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
+                                  pExpr->pRight, &r2, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
+      testcase( op==TK_ISNULL );
+      testcase( op==TK_NOTNULL );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      testcase( regFree1==0 );
+      break;
+    }
+    case TK_BETWEEN: {
+      /*    x BETWEEN y AND z
+      **
+      ** Is equivalent to 
+      **
+      **    x>=y AND x<=z
+      **
+      ** Code it as such, taking care to do the common subexpression
+      ** elementation of x.
+      */
+      Expr exprAnd;
+      Expr compLeft;
+      Expr compRight;
+      Expr exprX;
+
+      exprX = *pExpr->pLeft;
+      exprAnd.op = TK_AND;
+      exprAnd.pLeft = &compLeft;
+      exprAnd.pRight = &compRight;
+      compLeft.op = TK_GE;
+      compLeft.pLeft = &exprX;
+      compLeft.pRight = pExpr->pList->a[0].pExpr;
+      compRight.op = TK_LE;
+      compRight.pLeft = &exprX;
+      compRight.pRight = pExpr->pList->a[1].pExpr;
+      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
+      testcase( regFree1==0 );
+      exprX.op = TK_REGISTER;
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+      break;
+    }
+    default: {
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
+      sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
+      testcase( regFree1==0 );
+      testcase( jumpIfNull==0 );
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);  
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is false but execution
+** continues straight thru if the expression is true.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
+** is 0.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( v==0 || pExpr==0 ) return;
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+  switch( pExpr->op ){
+    case TK_AND: {
+      testcase( jumpIfNull==0 );
+      testcase( pParse->disableColCache==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      pParse->disableColCache++;
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      assert( pParse->disableColCache>0 );
+      pParse->disableColCache--;
+      break;
+    }
+    case TK_OR: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      testcase( jumpIfNull==0 );
+      testcase( pParse->disableColCache==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, jumpIfNull^SQLITE_JUMPIFNULL);
+      pParse->disableColCache++;
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      assert( pParse->disableColCache>0 );
+      pParse->disableColCache--;
+      sqlite3VdbeResolveLabel(v, d2);
+      break;
+    }
+    case TK_NOT: {
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      testcase( op==TK_LT );
+      testcase( op==TK_LE );
+      testcase( op==TK_GT );
+      testcase( op==TK_GE );
+      testcase( op==TK_EQ );
+      testcase( op==TK_NE );
+      testcase( jumpIfNull==0 );
+      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
+                                  pExpr->pRight, &r2, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      testcase( op==TK_ISNULL );
+      testcase( op==TK_NOTNULL );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      testcase( regFree1==0 );
+      break;
+    }
+    case TK_BETWEEN: {
+      /*    x BETWEEN y AND z
+      **
+      ** Is equivalent to 
+      **
+      **    x>=y AND x<=z
+      **
+      ** Code it as such, taking care to do the common subexpression
+      ** elementation of x.
+      */
+      Expr exprAnd;
+      Expr compLeft;
+      Expr compRight;
+      Expr exprX;
+
+      exprX = *pExpr->pLeft;
+      exprAnd.op = TK_AND;
+      exprAnd.pLeft = &compLeft;
+      exprAnd.pRight = &compRight;
+      compLeft.op = TK_GE;
+      compLeft.pLeft = &exprX;
+      compLeft.pRight = pExpr->pList->a[0].pExpr;
+      compRight.op = TK_LE;
+      compRight.pLeft = &exprX;
+      compRight.pRight = pExpr->pList->a[1].pExpr;
+      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
+      testcase( regFree1==0 );
+      exprX.op = TK_REGISTER;
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+      break;
+    }
+    default: {
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
+      sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
+      testcase( regFree1==0 );
+      testcase( jumpIfNull==0 );
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
+** if they are identical and return FALSE if they differ in any way.
+**
+** Sometimes this routine will return FALSE even if the two expressions
+** really are equivalent.  If we cannot prove that the expressions are
+** identical, we return FALSE just to be safe.  So if this routine
+** returns false, then you do not really know for certain if the two
+** expressions are the same.  But if you get a TRUE return, then you
+** can be sure the expressions are the same.  In the places where
+** this routine is used, it does not hurt to get an extra FALSE - that
+** just might result in some slightly slower code.  But returning
+** an incorrect TRUE could lead to a malfunction.
+*/
+SQLITE_PRIVATE int sqlite3ExprCompare(Expr *pA, Expr *pB){
+  int i;
+  if( pA==0||pB==0 ){
+    return pB==pA;
+  }
+  if( pA->op!=pB->op ) return 0;
+  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 0;
+  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
+  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
+  if( pA->pList ){
+    if( pB->pList==0 ) return 0;
+    if( pA->pList->nExpr!=pB->pList->nExpr ) return 0;
+    for(i=0; i<pA->pList->nExpr; i++){
+      if( !sqlite3ExprCompare(pA->pList->a[i].pExpr, pB->pList->a[i].pExpr) ){
+        return 0;
+      }
+    }
+  }else if( pB->pList ){
+    return 0;
+  }
+  if( pA->pSelect || pB->pSelect ) return 0;
+  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
+  if( pA->op!=TK_COLUMN && pA->token.z ){
+    if( pB->token.z==0 ) return 0;
+    if( pB->token.n!=pA->token.n ) return 0;
+    if( sqlite3StrNICmp((char*)pA->token.z,(char*)pB->token.z,pB->token.n)!=0 ){
+      return 0;
+    }
+  }
+  return 1;
+}
+
+
+/*
+** Add a new element to the pAggInfo->aCol[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aCol = sqlite3ArrayAllocate(
+       db,
+       pInfo->aCol,
+       sizeof(pInfo->aCol[0]),
+       3,
+       &pInfo->nColumn,
+       &pInfo->nColumnAlloc,
+       &i
+  );
+  return i;
+}    
+
+/*
+** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aFunc = sqlite3ArrayAllocate(
+       db, 
+       pInfo->aFunc,
+       sizeof(pInfo->aFunc[0]),
+       3,
+       &pInfo->nFunc,
+       &pInfo->nFuncAlloc,
+       &i
+  );
+  return i;
+}    
+
+/*
+** This is an xFunc for walkExprTree() used to implement 
+** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
+** for additional information.
+**
+** This routine analyzes the aggregate function at pExpr.
+*/
+static int analyzeAggregate(void *pArg, Expr *pExpr){
+  int i;
+  NameContext *pNC = (NameContext *)pArg;
+  Parse *pParse = pNC->pParse;
+  SrcList *pSrcList = pNC->pSrcList;
+  AggInfo *pAggInfo = pNC->pAggInfo;
+
+  switch( pExpr->op ){
+    case TK_AGG_COLUMN:
+    case TK_COLUMN: {
+      /* Check to see if the column is in one of the tables in the FROM
+      ** clause of the aggregate query */
+      if( pSrcList ){
+        struct SrcList_item *pItem = pSrcList->a;
+        for(i=0; i<pSrcList->nSrc; i++, pItem++){
+          struct AggInfo_col *pCol;
+          if( pExpr->iTable==pItem->iCursor ){
+            /* If we reach this point, it means that pExpr refers to a table
+            ** that is in the FROM clause of the aggregate query.  
+            **
+            ** Make an entry for the column in pAggInfo->aCol[] if there
+            ** is not an entry there already.
+            */
+            int k;
+            pCol = pAggInfo->aCol;
+            for(k=0; k<pAggInfo->nColumn; k++, pCol++){
+              if( pCol->iTable==pExpr->iTable &&
+                  pCol->iColumn==pExpr->iColumn ){
+                break;
+              }
+            }
+            if( (k>=pAggInfo->nColumn)
+             && (k = addAggInfoColumn(pParse->db, pAggInfo))>=0 
+            ){
+              pCol = &pAggInfo->aCol[k];
+              pCol->pTab = pExpr->pTab;
+              pCol->iTable = pExpr->iTable;
+              pCol->iColumn = pExpr->iColumn;
+              pCol->iMem = ++pParse->nMem;
+              pCol->iSorterColumn = -1;
+              pCol->pExpr = pExpr;
+              if( pAggInfo->pGroupBy ){
+                int j, n;
+                ExprList *pGB = pAggInfo->pGroupBy;
+                struct ExprList_item *pTerm = pGB->a;
+                n = pGB->nExpr;
+                for(j=0; j<n; j++, pTerm++){
+                  Expr *pE = pTerm->pExpr;
+                  if( pE->op==TK_COLUMN && pE->iTable==pExpr->iTable &&
+                      pE->iColumn==pExpr->iColumn ){
+                    pCol->iSorterColumn = j;
+                    break;
+                  }
+                }
+              }
+              if( pCol->iSorterColumn<0 ){
+                pCol->iSorterColumn = pAggInfo->nSortingColumn++;
+              }
+            }
+            /* There is now an entry for pExpr in pAggInfo->aCol[] (either
+            ** because it was there before or because we just created it).
+            ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
+            ** pAggInfo->aCol[] entry.
+            */
+            pExpr->pAggInfo = pAggInfo;
+            pExpr->op = TK_AGG_COLUMN;
+            pExpr->iAgg = k;
+            break;
+          } /* endif pExpr->iTable==pItem->iCursor */
+        } /* end loop over pSrcList */
+      }
+      return 1;
+    }
+    case TK_AGG_FUNCTION: {
+      /* The pNC->nDepth==0 test causes aggregate functions in subqueries
+      ** to be ignored */
+      if( pNC->nDepth==0 ){
+        /* Check to see if pExpr is a duplicate of another aggregate 
+        ** function that is already in the pAggInfo structure
+        */
+        struct AggInfo_func *pItem = pAggInfo->aFunc;
+        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
+          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
+            break;
+          }
+        }
+        if( i>=pAggInfo->nFunc ){
+          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
+          */
+          u8 enc = ENC(pParse->db);
+          i = addAggInfoFunc(pParse->db, pAggInfo);
+          if( i>=0 ){
+            pItem = &pAggInfo->aFunc[i];
+            pItem->pExpr = pExpr;
+            pItem->iMem = ++pParse->nMem;
+            pItem->pFunc = sqlite3FindFunction(pParse->db,
+                   (char*)pExpr->token.z, pExpr->token.n,
+                   pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
+            if( pExpr->flags & EP_Distinct ){
+              pItem->iDistinct = pParse->nTab++;
+            }else{
+              pItem->iDistinct = -1;
+            }
+          }
+        }
+        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
+        */
+        pExpr->iAgg = i;
+        pExpr->pAggInfo = pAggInfo;
+        return 1;
+      }
+    }
+  }
+
+  /* Recursively walk subqueries looking for TK_COLUMN nodes that need
+  ** to be changed to TK_AGG_COLUMN.  But increment nDepth so that
+  ** TK_AGG_FUNCTION nodes in subqueries will be unchanged.
+  */
+  if( pExpr->pSelect ){
+    pNC->nDepth++;
+    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
+    pNC->nDepth--;
+  }
+  return 0;
+}
+
+/*
+** Analyze the given expression looking for aggregate functions and
+** for variables that need to be added to the pParse->aAgg[] array.
+** Make additional entries to the pParse->aAgg[] array as necessary.
+**
+** This routine should only be called after the expression has been
+** analyzed by sqlite3ExprResolveNames().
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
+  walkExprTree(pExpr, analyzeAggregate, pNC);
+}
+
+/*
+** Call sqlite3ExprAnalyzeAggregates() for every expression in an
+** expression list.  Return the number of errors.
+**
+** If an error is found, the analysis is cut short.
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
+  struct ExprList_item *pItem;
+  int i;
+  if( pList ){
+    for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+      sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
+    }
+  }
+}
+
+/*
+** Allocate or deallocate temporary use registers during code generation.
+*/
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse *pParse){
+  int i, r;
+  if( pParse->nTempReg==0 ){
+    return ++pParse->nMem;
+  }
+  for(i=0; i<pParse->nTempReg; i++){
+    r = pParse->aTempReg[i];
+    if( usedAsColumnCache(pParse, r, r) ) continue;
+  }
+  if( i>=pParse->nTempReg ){
+    return ++pParse->nMem;
+  }
+  while( i<pParse->nTempReg-1 ){
+    pParse->aTempReg[i] = pParse->aTempReg[i+1];
+  }
+  pParse->nTempReg--;
+  return r;
+}
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
+  if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+    pParse->aTempReg[pParse->nTempReg++] = iReg;
+  }
+}
+
+/*
+** Allocate or deallocate a block of nReg consecutive registers
+*/
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse *pParse, int nReg){
+  int i, n;
+  i = pParse->iRangeReg;
+  n = pParse->nRangeReg;
+  if( nReg<=n && !usedAsColumnCache(pParse, i, i+n-1) ){
+    pParse->iRangeReg += nReg;
+    pParse->nRangeReg -= nReg;
+  }else{
+    i = pParse->nMem+1;
+    pParse->nMem += nReg;
+  }
+  return i;
+}
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  if( nReg>pParse->nRangeReg ){
+    pParse->nRangeReg = nReg;
+    pParse->iRangeReg = iReg;
+  }
+}
+
+/************** End of expr.c ************************************************/
+/************** Begin file alter.c *******************************************/
+/*
+** 2005 February 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that used to generate VDBE code
+** that implements the ALTER TABLE command.
+**
+** $Id: alter.c,v 1.44 2008/05/09 14:17:52 drh Exp $
+*/
+
+/*
+** The code in this file only exists if we are not omitting the
+** ALTER TABLE logic from the build.
+*/
+#ifndef SQLITE_OMIT_ALTERTABLE
+
+
+/*
+** This function is used by SQL generated to implement the 
+** ALTER TABLE command. The first argument is the text of a CREATE TABLE or
+** CREATE INDEX command. The second is a table name. The table name in 
+** the CREATE TABLE or CREATE INDEX statement is replaced with the third
+** argument and the result returned. Examples:
+**
+** sqlite_rename_table('CREATE TABLE abc(a, b, c)', 'def')
+**     -> 'CREATE TABLE def(a, b, c)'
+**
+** sqlite_rename_table('CREATE INDEX i ON abc(a)', 'def')
+**     -> 'CREATE INDEX i ON def(a, b, c)'
+*/
+static void renameTableFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned char const *zSql = sqlite3_value_text(argv[0]);
+  unsigned char const *zTableName = sqlite3_value_text(argv[1]);
+
+  int token;
+  Token tname;
+  unsigned char const *zCsr = zSql;
+  int len = 0;
+  char *zRet;
+
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  /* The principle used to locate the table name in the CREATE TABLE 
+  ** statement is that the table name is the first non-space token that
+  ** is immediately followed by a left parenthesis - TK_LP - or "USING" TK_USING.
+  */
+  if( zSql ){
+    do {
+      if( !*zCsr ){
+        /* Ran out of input before finding an opening bracket. Return NULL. */
+        return;
+      }
+
+      /* Store the token that zCsr points to in tname. */
+      tname.z = zCsr;
+      tname.n = len;
+
+      /* Advance zCsr to the next token. Store that token type in 'token',
+      ** and its length in 'len' (to be used next iteration of this loop).
+      */
+      do {
+        zCsr += len;
+        len = sqlite3GetToken(zCsr, &token);
+      } while( token==TK_SPACE || token==TK_COMMENT );
+      assert( len>0 );
+    } while( token!=TK_LP && token!=TK_USING );
+
+    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", tname.z - zSql, zSql, 
+       zTableName, tname.z+tname.n);
+    sqlite3_result_text(context, zRet, -1, sqlite3_free);
+  }
+}
+
+#ifndef SQLITE_OMIT_TRIGGER
+/* This function is used by SQL generated to implement the
+** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER 
+** statement. The second is a table name. The table name in the CREATE 
+** TRIGGER statement is replaced with the third argument and the result 
+** returned. This is analagous to renameTableFunc() above, except for CREATE
+** TRIGGER, not CREATE INDEX and CREATE TABLE.
+*/
+static void renameTriggerFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned char const *zSql = sqlite3_value_text(argv[0]);
+  unsigned char const *zTableName = sqlite3_value_text(argv[1]);
+
+  int token;
+  Token tname;
+  int dist = 3;
+  unsigned char const *zCsr = zSql;
+  int len = 0;
+  char *zRet;
+
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  /* The principle used to locate the table name in the CREATE TRIGGER 
+  ** statement is that the table name is the first token that is immediatedly
+  ** preceded by either TK_ON or TK_DOT and immediatedly followed by one
+  ** of TK_WHEN, TK_BEGIN or TK_FOR.
+  */
+  if( zSql ){
+    do {
+
+      if( !*zCsr ){
+        /* Ran out of input before finding the table name. Return NULL. */
+        return;
+      }
+
+      /* Store the token that zCsr points to in tname. */
+      tname.z = zCsr;
+      tname.n = len;
+
+      /* Advance zCsr to the next token. Store that token type in 'token',
+      ** and its length in 'len' (to be used next iteration of this loop).
+      */
+      do {
+        zCsr += len;
+        len = sqlite3GetToken(zCsr, &token);
+      }while( token==TK_SPACE );
+      assert( len>0 );
+
+      /* Variable 'dist' stores the number of tokens read since the most
+      ** recent TK_DOT or TK_ON. This means that when a WHEN, FOR or BEGIN 
+      ** token is read and 'dist' equals 2, the condition stated above
+      ** to be met.
+      **
+      ** Note that ON cannot be a database, table or column name, so
+      ** there is no need to worry about syntax like 
+      ** "CREATE TRIGGER ... ON ON.ON BEGIN ..." etc.
+      */
+      dist++;
+      if( token==TK_DOT || token==TK_ON ){
+        dist = 0;
+      }
+    } while( dist!=2 || (token!=TK_WHEN && token!=TK_FOR && token!=TK_BEGIN) );
+
+    /* Variable tname now contains the token that is the old table-name
+    ** in the CREATE TRIGGER statement.
+    */
+    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", tname.z - zSql, zSql, 
+       zTableName, tname.z+tname.n);
+    sqlite3_result_text(context, zRet, -1, sqlite3_free);
+  }
+}
+#endif   /* !SQLITE_OMIT_TRIGGER */
+
+/*
+** Register built-in functions used to help implement ALTER TABLE
+*/
+SQLITE_PRIVATE void sqlite3AlterFunctions(sqlite3 *db){
+  static const struct {
+     char *zName;
+     signed char nArg;
+     void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
+  } aFuncs[] = {
+    { "sqlite_rename_table",    2, renameTableFunc},
+#ifndef SQLITE_OMIT_TRIGGER
+    { "sqlite_rename_trigger",  2, renameTriggerFunc},
+#endif
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
+        SQLITE_UTF8, 0, aFuncs[i].xFunc, 0, 0);
+  }
+}
+
+/*
+** Generate the text of a WHERE expression which can be used to select all
+** temporary triggers on table pTab from the sqlite_temp_master table. If
+** table pTab has no temporary triggers, or is itself stored in the 
+** temporary database, NULL is returned.
+*/
+static char *whereTempTriggers(Parse *pParse, Table *pTab){
+  Trigger *pTrig;
+  char *zWhere = 0;
+  char *tmp = 0;
+  const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */
+
+  /* If the table is not located in the temp-db (in which case NULL is 
+  ** returned, loop through the tables list of triggers. For each trigger
+  ** that is not part of the temp-db schema, add a clause to the WHERE 
+  ** expression being built up in zWhere.
+  */
+  if( pTab->pSchema!=pTempSchema ){
+    sqlite3 *db = pParse->db;
+    for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
+      if( pTrig->pSchema==pTempSchema ){
+        if( !zWhere ){
+          zWhere = sqlite3MPrintf(db, "name=%Q", pTrig->name);
+        }else{
+          tmp = zWhere;
+          zWhere = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, pTrig->name);
+          sqlite3_free(tmp);
+        }
+      }
+    }
+  }
+  return zWhere;
+}
+
+/*
+** Generate code to drop and reload the internal representation of table
+** pTab from the database, including triggers and temporary triggers.
+** Argument zName is the name of the table in the database schema at
+** the time the generated code is executed. This can be different from
+** pTab->zName if this function is being called to code part of an 
+** "ALTER TABLE RENAME TO" statement.
+*/
+static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
+  Vdbe *v;
+  char *zWhere;
+  int iDb;                   /* Index of database containing pTab */
+#ifndef SQLITE_OMIT_TRIGGER
+  Trigger *pTrig;
+#endif
+
+  v = sqlite3GetVdbe(pParse);
+  if( !v ) return;
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  assert( iDb>=0 );
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* Drop any table triggers from the internal schema. */
+  for(pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext){
+    int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
+    assert( iTrigDb==iDb || iTrigDb==1 );
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->name, 0);
+  }
+#endif
+
+  /* Drop the table and index from the internal schema */
+  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
+
+  /* Reload the table, index and permanent trigger schemas. */
+  zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
+  if( !zWhere ) return;
+  sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* Now, if the table is not stored in the temp database, reload any temp 
+  ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
+  */
+  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
+    sqlite3VdbeAddOp4(v, OP_ParseSchema, 1, 0, 0, zWhere, P4_DYNAMIC);
+  }
+#endif
+}
+
+/*
+** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy" 
+** command. 
+*/
+SQLITE_PRIVATE void sqlite3AlterRenameTable(
+  Parse *pParse,            /* Parser context. */
+  SrcList *pSrc,            /* The table to rename. */
+  Token *pName              /* The new table name. */
+){
+  int iDb;                  /* Database that contains the table */
+  char *zDb;                /* Name of database iDb */
+  Table *pTab;              /* Table being renamed */
+  char *zName = 0;          /* NULL-terminated version of pName */ 
+  sqlite3 *db = pParse->db; /* Database connection */
+  int nTabName;             /* Number of UTF-8 characters in zTabName */
+  const char *zTabName;     /* Original name of the table */
+  Vdbe *v;
+#ifndef SQLITE_OMIT_TRIGGER
+  char *zWhere = 0;         /* Where clause to locate temp triggers */
+#endif
+  int isVirtualRename = 0;  /* True if this is a v-table with an xRename() */
+  
+  if( db->mallocFailed ) goto exit_rename_table;
+  assert( pSrc->nSrc==1 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+
+  pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
+  if( !pTab ) goto exit_rename_table;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  zDb = db->aDb[iDb].zName;
+
+  /* Get a NULL terminated version of the new table name. */
+  zName = sqlite3NameFromToken(db, pName);
+  if( !zName ) goto exit_rename_table;
+
+  /* Check that a table or index named 'zName' does not already exist
+  ** in database iDb. If so, this is an error.
+  */
+  if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
+    sqlite3ErrorMsg(pParse, 
+        "there is already another table or index with this name: %s", zName);
+    goto exit_rename_table;
+  }
+
+  /* Make sure it is not a system table being altered, or a reserved name
+  ** that the table is being renamed to.
+  */
+  if( strlen(pTab->zName)>6 && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
+    goto exit_rename_table;
+  }
+  if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
+    goto exit_rename_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  if( pTab->pSelect ){
+    sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_rename_table;
+  }
+  if( IsVirtual(pTab) && pTab->pMod->pModule->xRename ){
+    isVirtualRename = 1;
+  }
+#endif
+
+  /* Begin a transaction and code the VerifyCookie for database iDb. 
+  ** Then modify the schema cookie (since the ALTER TABLE modifies the
+  ** schema). Open a statement transaction if the table is a virtual
+  ** table.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto exit_rename_table;
+  }
+  sqlite3BeginWriteOperation(pParse, isVirtualRename, iDb);
+  sqlite3ChangeCookie(pParse, iDb);
+
+  /* If this is a virtual table, invoke the xRename() function if
+  ** one is defined. The xRename() callback will modify the names
+  ** of any resources used by the v-table implementation (including other
+  ** SQLite tables) that are identified by the name of the virtual table.
+  */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( isVirtualRename ){
+    int i = ++pParse->nMem;
+    sqlite3VdbeAddOp4(v, OP_String8, 0, i, 0, zName, 0);
+    sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pTab->pVtab, P4_VTAB);
+  }
+#endif
+
+  /* figure out how many UTF-8 characters are in zName */
+  zTabName = pTab->zName;
+  nTabName = sqlite3Utf8CharLen(zTabName, -1);
+
+  /* Modify the sqlite_master table to use the new table name. */
+  sqlite3NestedParse(pParse,
+      "UPDATE %Q.%s SET "
+#ifdef SQLITE_OMIT_TRIGGER
+          "sql = sqlite_rename_table(sql, %Q), "
+#else
+          "sql = CASE "
+            "WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
+            "ELSE sqlite_rename_table(sql, %Q) END, "
+#endif
+          "tbl_name = %Q, "
+          "name = CASE "
+            "WHEN type='table' THEN %Q "
+            "WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
+             "'sqlite_autoindex_' || %Q || substr(name,%d+18) "
+            "ELSE name END "
+      "WHERE tbl_name=%Q AND "
+          "(type='table' OR type='index' OR type='trigger');", 
+      zDb, SCHEMA_TABLE(iDb), zName, zName, zName, 
+#ifndef SQLITE_OMIT_TRIGGER
+      zName,
+#endif
+      zName, nTabName, zTabName
+  );
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* If the sqlite_sequence table exists in this database, then update 
+  ** it with the new table name.
+  */
+  if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
+    sqlite3NestedParse(pParse,
+        "UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
+        zDb, zName, pTab->zName);
+  }
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* If there are TEMP triggers on this table, modify the sqlite_temp_master
+  ** table. Don't do this if the table being ALTERed is itself located in
+  ** the temp database.
+  */
+  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
+    sqlite3NestedParse(pParse, 
+        "UPDATE sqlite_temp_master SET "
+            "sql = sqlite_rename_trigger(sql, %Q), "
+            "tbl_name = %Q "
+            "WHERE %s;", zName, zName, zWhere);
+    sqlite3_free(zWhere);
+  }
+#endif
+
+  /* Drop and reload the internal table schema. */
+  reloadTableSchema(pParse, pTab, zName);
+
+exit_rename_table:
+  sqlite3SrcListDelete(pSrc);
+  sqlite3_free(zName);
+}
+
+
+/*
+** This function is called after an "ALTER TABLE ... ADD" statement
+** has been parsed. Argument pColDef contains the text of the new
+** column definition.
+**
+** The Table structure pParse->pNewTable was extended to include
+** the new column during parsing.
+*/
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
+  Table *pNew;              /* Copy of pParse->pNewTable */
+  Table *pTab;              /* Table being altered */
+  int iDb;                  /* Database number */
+  const char *zDb;          /* Database name */
+  const char *zTab;         /* Table name */
+  char *zCol;               /* Null-terminated column definition */
+  Column *pCol;             /* The new column */
+  Expr *pDflt;              /* Default value for the new column */
+  sqlite3 *db;              /* The database connection; */
+
+  if( pParse->nErr ) return;
+  pNew = pParse->pNewTable;
+  assert( pNew );
+
+  db = pParse->db;
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
+  zDb = db->aDb[iDb].zName;
+  zTab = pNew->zName;
+  pCol = &pNew->aCol[pNew->nCol-1];
+  pDflt = pCol->pDflt;
+  pTab = sqlite3FindTable(db, zTab, zDb);
+  assert( pTab );
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    return;
+  }
+#endif
+
+  /* If the default value for the new column was specified with a 
+  ** literal NULL, then set pDflt to 0. This simplifies checking
+  ** for an SQL NULL default below.
+  */
+  if( pDflt && pDflt->op==TK_NULL ){
+    pDflt = 0;
+  }
+
+  /* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
+  ** If there is a NOT NULL constraint, then the default value for the
+  ** column must not be NULL.
+  */
+  if( pCol->isPrimKey ){
+    sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
+    return;
+  }
+  if( pNew->pIndex ){
+    sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
+    return;
+  }
+  if( pCol->notNull && !pDflt ){
+    sqlite3ErrorMsg(pParse, 
+        "Cannot add a NOT NULL column with default value NULL");
+    return;
+  }
+
+  /* Ensure the default expression is something that sqlite3ValueFromExpr()
+  ** can handle (i.e. not CURRENT_TIME etc.)
+  */
+  if( pDflt ){
+    sqlite3_value *pVal;
+    if( sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_NONE, &pVal) ){
+      db->mallocFailed = 1;
+      return;
+    }
+    if( !pVal ){
+      sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
+      return;
+    }
+    sqlite3ValueFree(pVal);
+  }
+
+  /* Modify the CREATE TABLE statement. */
+  zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
+  if( zCol ){
+    char *zEnd = &zCol[pColDef->n-1];
+    while( (zEnd>zCol && *zEnd==';') || isspace(*(unsigned char *)zEnd) ){
+      *zEnd-- = '\0';
+    }
+    sqlite3NestedParse(pParse, 
+        "UPDATE \"%w\".%s SET "
+          "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
+        "WHERE type = 'table' AND name = %Q", 
+      zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
+      zTab
+    );
+    sqlite3_free(zCol);
+  }
+
+  /* If the default value of the new column is NULL, then set the file
+  ** format to 2. If the default value of the new column is not NULL,
+  ** the file format becomes 3.
+  */
+  sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
+
+  /* Reload the schema of the modified table. */
+  reloadTableSchema(pParse, pTab, pTab->zName);
+}
+
+/*
+** This function is called by the parser after the table-name in
+** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument 
+** pSrc is the full-name of the table being altered.
+**
+** This routine makes a (partial) copy of the Table structure
+** for the table being altered and sets Parse.pNewTable to point
+** to it. Routines called by the parser as the column definition
+** is parsed (i.e. sqlite3AddColumn()) add the new Column data to 
+** the copy. The copy of the Table structure is deleted by tokenize.c 
+** after parsing is finished.
+**
+** Routine sqlite3AlterFinishAddColumn() will be called to complete
+** coding the "ALTER TABLE ... ADD" statement.
+*/
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
+  Table *pNew;
+  Table *pTab;
+  Vdbe *v;
+  int iDb;
+  int i;
+  int nAlloc;
+  sqlite3 *db = pParse->db;
+
+  /* Look up the table being altered. */
+  assert( pParse->pNewTable==0 );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  if( db->mallocFailed ) goto exit_begin_add_column;
+  pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
+  if( !pTab ) goto exit_begin_add_column;
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
+    goto exit_begin_add_column;
+  }
+#endif
+
+  /* Make sure this is not an attempt to ALTER a view. */
+  if( pTab->pSelect ){
+    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
+    goto exit_begin_add_column;
+  }
+
+  assert( pTab->addColOffset>0 );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
+  /* Put a copy of the Table struct in Parse.pNewTable for the
+  ** sqlite3AddColumn() function and friends to modify.
+  */
+  pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
+  if( !pNew ) goto exit_begin_add_column;
+  pParse->pNewTable = pNew;
+  pNew->nRef = 1;
+  pNew->nCol = pTab->nCol;
+  assert( pNew->nCol>0 );
+  nAlloc = (((pNew->nCol-1)/8)*8)+8;
+  assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
+  pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
+  pNew->zName = sqlite3DbStrDup(db, pTab->zName);
+  if( !pNew->aCol || !pNew->zName ){
+    db->mallocFailed = 1;
+    goto exit_begin_add_column;
+  }
+  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
+  for(i=0; i<pNew->nCol; i++){
+    Column *pCol = &pNew->aCol[i];
+    pCol->zName = sqlite3DbStrDup(db, pCol->zName);
+    pCol->zColl = 0;
+    pCol->zType = 0;
+    pCol->pDflt = 0;
+  }
+  pNew->pSchema = db->aDb[iDb].pSchema;
+  pNew->addColOffset = pTab->addColOffset;
+  pNew->nRef = 1;
+
+  /* Begin a transaction and increment the schema cookie.  */
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  v = sqlite3GetVdbe(pParse);
+  if( !v ) goto exit_begin_add_column;
+  sqlite3ChangeCookie(pParse, iDb);
+
+exit_begin_add_column:
+  sqlite3SrcListDelete(pSrc);
+  return;
+}
+#endif  /* SQLITE_ALTER_TABLE */
+
+/************** End of alter.c ***********************************************/
+/************** Begin file analyze.c *****************************************/
+/*
+** 2005 July 8
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code associated with the ANALYZE command.
+**
+** @(#) $Id: analyze.c,v 1.42 2008/03/25 09:47:35 danielk1977 Exp $
+*/
+#ifndef SQLITE_OMIT_ANALYZE
+
+/*
+** This routine generates code that opens the sqlite_stat1 table on cursor
+** iStatCur.
+**
+** If the sqlite_stat1 tables does not previously exist, it is created.
+** If it does previously exist, all entires associated with table zWhere
+** are removed.  If zWhere==0 then all entries are removed.
+*/
+static void openStatTable(
+  Parse *pParse,          /* Parsing context */
+  int iDb,                /* The database we are looking in */
+  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
+  const char *zWhere      /* Delete entries associated with this table */
+){
+  sqlite3 *db = pParse->db;
+  Db *pDb;
+  int iRootPage;
+  int createStat1 = 0;
+  Table *pStat;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+
+  if( v==0 ) return;
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3VdbeDb(v)==db );
+  pDb = &db->aDb[iDb];
+  if( (pStat = sqlite3FindTable(db, "sqlite_stat1", pDb->zName))==0 ){
+    /* The sqlite_stat1 tables does not exist.  Create it.  
+    ** Note that a side-effect of the CREATE TABLE statement is to leave
+    ** the rootpage of the new table in register pParse->regRoot.  This is
+    ** important because the OpenWrite opcode below will be needing it. */
+    sqlite3NestedParse(pParse,
+      "CREATE TABLE %Q.sqlite_stat1(tbl,idx,stat)",
+      pDb->zName
+    );
+    iRootPage = pParse->regRoot;
+    createStat1 = 1;  /* Cause rootpage to be taken from top of stack */
+  }else if( zWhere ){
+    /* The sqlite_stat1 table exists.  Delete all entries associated with
+    ** the table zWhere. */
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q",
+       pDb->zName, zWhere
+    );
+    iRootPage = pStat->tnum;
+  }else{
+    /* The sqlite_stat1 table already exists.  Delete all rows. */
+    iRootPage = pStat->tnum;
+    sqlite3VdbeAddOp2(v, OP_Clear, pStat->tnum, iDb);
+  }
+
+  /* Open the sqlite_stat1 table for writing. Unless it was created
+  ** by this vdbe program, lock it for writing at the shared-cache level. 
+  ** If this vdbe did create the sqlite_stat1 table, then it must have 
+  ** already obtained a schema-lock, making the write-lock redundant.
+  */
+  if( !createStat1 ){
+    sqlite3TableLock(pParse, iDb, iRootPage, 1, "sqlite_stat1");
+  }
+  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, 3);
+  sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur, iRootPage, iDb);
+  sqlite3VdbeChangeP5(v, createStat1);
+}
+
+/*
+** Generate code to do an analysis of all indices associated with
+** a single table.
+*/
+static void analyzeOneTable(
+  Parse *pParse,   /* Parser context */
+  Table *pTab,     /* Table whose indices are to be analyzed */
+  int iStatCur,    /* Cursor that writes to the sqlite_stat1 table */
+  int iMem         /* Available memory locations begin here */
+){
+  Index *pIdx;     /* An index to being analyzed */
+  int iIdxCur;     /* Cursor number for index being analyzed */
+  int nCol;        /* Number of columns in the index */
+  Vdbe *v;         /* The virtual machine being built up */
+  int i;           /* Loop counter */
+  int topOfLoop;   /* The top of the loop */
+  int endOfLoop;   /* The end of the loop */
+  int addr;        /* The address of an instruction */
+  int iDb;         /* Index of database containing pTab */
+
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 || pTab==0 || pTab->pIndex==0 ){
+    /* Do no analysis for tables that have no indices */
+    return;
+  }
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  assert( iDb>=0 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
+      pParse->db->aDb[iDb].zName ) ){
+    return;
+  }
+#endif
+
+  /* Establish a read-lock on the table at the shared-cache level. */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+  iIdxCur = pParse->nTab;
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
+    int regFields;    /* Register block for building records */
+    int regRec;       /* Register holding completed record */
+    int regTemp;      /* Temporary use register */
+    int regCol;       /* Content of a column from the table being analyzed */
+    int regRowid;     /* Rowid for the inserted record */
+    int regF2;
+
+    /* Open a cursor to the index to be analyzed
+    */
+    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
+    nCol = pIdx->nColumn;
+    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nCol+1);
+    sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb,
+        (char *)pKey, P4_KEYINFO_HANDOFF);
+    VdbeComment((v, "%s", pIdx->zName));
+    regFields = iMem+nCol*2;
+    regTemp = regRowid = regCol = regFields+3;
+    regRec = regCol+1;
+    if( regRec>pParse->nMem ){
+      pParse->nMem = regRec;
+    }
+
+    /* Memory cells are used as follows:
+    **
+    **    mem[iMem]:             The total number of rows in the table.
+    **    mem[iMem+1]:           Number of distinct values in column 1
+    **    ...
+    **    mem[iMem+nCol]:        Number of distinct values in column N
+    **    mem[iMem+nCol+1]       Last observed value of column 1
+    **    ...
+    **    mem[iMem+nCol+nCol]:   Last observed value of column N
+    **
+    ** Cells iMem through iMem+nCol are initialized to 0.  The others
+    ** are initialized to NULL.
+    */
+    for(i=0; i<=nCol; i++){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iMem+i);
+    }
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, iMem+nCol+i+1);
+    }
+
+    /* Do the analysis.
+    */
+    endOfLoop = sqlite3VdbeMakeLabel(v);
+    sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop);
+    topOfLoop = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1);
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol);
+      sqlite3VdbeAddOp3(v, OP_Ne, regCol, 0, iMem+nCol+i+1);
+      /**** TODO:  add collating sequence *****/
+      sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+    }
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop);
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeJumpHere(v, topOfLoop + 2*(i + 1));
+      sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1);
+      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1);
+    }
+    sqlite3VdbeResolveLabel(v, endOfLoop);
+    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop);
+    sqlite3VdbeAddOp1(v, OP_Close, iIdxCur);
+
+    /* Store the results.  
+    **
+    ** The result is a single row of the sqlite_stat1 table.  The first
+    ** two columns are the names of the table and index.  The third column
+    ** is a string composed of a list of integer statistics about the
+    ** index.  The first integer in the list is the total number of entires
+    ** in the index.  There is one additional integer in the list for each
+    ** column of the table.  This additional integer is a guess of how many
+    ** rows of the table the index will select.  If D is the count of distinct
+    ** values and K is the total number of rows, then the integer is computed
+    ** as:
+    **
+    **        I = (K+D-1)/D
+    **
+    ** If K==0 then no entry is made into the sqlite_stat1 table.  
+    ** If K>0 then it is always the case the D>0 so division by zero
+    ** is never possible.
+    */
+    addr = sqlite3VdbeAddOp1(v, OP_IfNot, iMem);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, regFields, 0, pTab->zName, 0);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, regFields+1, 0, pIdx->zName, 0);
+    regF2 = regFields+2;
+    sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regF2);
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeAddOp4(v, OP_String8, 0, regTemp, 0, " ", 0);
+      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regF2, regF2);
+      sqlite3VdbeAddOp3(v, OP_Add, iMem, iMem+i+1, regTemp);
+      sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1);
+      sqlite3VdbeAddOp3(v, OP_Divide, iMem+i+1, regTemp, regTemp);
+      sqlite3VdbeAddOp1(v, OP_ToInt, regTemp);
+      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regF2, regF2);
+    }
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regFields, 3, regRec, "aaa", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regRowid);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+    sqlite3VdbeJumpHere(v, addr);
+  }
+}
+
+/*
+** Generate code that will cause the most recent index analysis to
+** be laoded into internal hash tables where is can be used.
+*/
+static void loadAnalysis(Parse *pParse, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp1(v, OP_LoadAnalysis, iDb);
+  }
+}
+
+/*
+** Generate code that will do an analysis of an entire database
+*/
+static void analyzeDatabase(Parse *pParse, int iDb){
+  sqlite3 *db = pParse->db;
+  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
+  HashElem *k;
+  int iStatCur;
+  int iMem;
+
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab++;
+  openStatTable(pParse, iDb, iStatCur, 0);
+  iMem = pParse->nMem+1;
+  for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+    Table *pTab = (Table*)sqliteHashData(k);
+    analyzeOneTable(pParse, pTab, iStatCur, iMem);
+  }
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code that will do an analysis of a single table in
+** a database.
+*/
+static void analyzeTable(Parse *pParse, Table *pTab){
+  int iDb;
+  int iStatCur;
+
+  assert( pTab!=0 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab++;
+  openStatTable(pParse, iDb, iStatCur, pTab->zName);
+  analyzeOneTable(pParse, pTab, iStatCur, pParse->nMem+1);
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code for the ANALYZE command.  The parser calls this routine
+** when it recognizes an ANALYZE command.
+**
+**        ANALYZE                            -- 1
+**        ANALYZE  <database>                -- 2
+**        ANALYZE  ?<database>.?<tablename>  -- 3
+**
+** Form 1 causes all indices in all attached databases to be analyzed.
+** Form 2 analyzes all indices the single database named.
+** Form 3 analyzes all indices associated with the named table.
+*/
+SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
+  sqlite3 *db = pParse->db;
+  int iDb;
+  int i;
+  char *z, *zDb;
+  Table *pTab;
+  Token *pTableName;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  if( pName1==0 ){
+    /* Form 1:  Analyze everything */
+    for(i=0; i<db->nDb; i++){
+      if( i==1 ) continue;  /* Do not analyze the TEMP database */
+      analyzeDatabase(pParse, i);
+    }
+  }else if( pName2==0 || pName2->n==0 ){
+    /* Form 2:  Analyze the database or table named */
+    iDb = sqlite3FindDb(db, pName1);
+    if( iDb>=0 ){
+      analyzeDatabase(pParse, iDb);
+    }else{
+      z = sqlite3NameFromToken(db, pName1);
+      if( z ){
+        pTab = sqlite3LocateTable(pParse, 0, z, 0);
+        sqlite3_free(z);
+        if( pTab ){
+          analyzeTable(pParse, pTab);
+        }
+      }
+    }
+  }else{
+    /* Form 3: Analyze the fully qualified table name */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
+    if( iDb>=0 ){
+      zDb = db->aDb[iDb].zName;
+      z = sqlite3NameFromToken(db, pTableName);
+      if( z ){
+        pTab = sqlite3LocateTable(pParse, 0, z, zDb);
+        sqlite3_free(z);
+        if( pTab ){
+          analyzeTable(pParse, pTab);
+        }
+      }
+    }   
+  }
+}
+
+/*
+** Used to pass information from the analyzer reader through to the
+** callback routine.
+*/
+typedef struct analysisInfo analysisInfo;
+struct analysisInfo {
+  sqlite3 *db;
+  const char *zDatabase;
+};
+
+/*
+** This callback is invoked once for each index when reading the
+** sqlite_stat1 table.  
+**
+**     argv[0] = name of the index
+**     argv[1] = results of analysis - on integer for each column
+*/
+static int analysisLoader(void *pData, int argc, char **argv, char **azNotUsed){
+  analysisInfo *pInfo = (analysisInfo*)pData;
+  Index *pIndex;
+  int i, c;
+  unsigned int v;
+  const char *z;
+
+  assert( argc==2 );
+  if( argv==0 || argv[0]==0 || argv[1]==0 ){
+    return 0;
+  }
+  pIndex = sqlite3FindIndex(pInfo->db, argv[0], pInfo->zDatabase);
+  if( pIndex==0 ){
+    return 0;
+  }
+  z = argv[1];
+  for(i=0; *z && i<=pIndex->nColumn; i++){
+    v = 0;
+    while( (c=z[0])>='0' && c<='9' ){
+      v = v*10 + c - '0';
+      z++;
+    }
+    pIndex->aiRowEst[i] = v;
+    if( *z==' ' ) z++;
+  }
+  return 0;
+}
+
+/*
+** Load the content of the sqlite_stat1 table into the index hash tables.
+*/
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
+  analysisInfo sInfo;
+  HashElem *i;
+  char *zSql;
+  int rc;
+
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+
+  /* Clear any prior statistics */
+  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    sqlite3DefaultRowEst(pIdx);
+  }
+
+  /* Check to make sure the sqlite_stat1 table existss */
+  sInfo.db = db;
+  sInfo.zDatabase = db->aDb[iDb].zName;
+  if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
+     return SQLITE_ERROR;
+  }
+
+
+  /* Load new statistics out of the sqlite_stat1 table */
+  zSql = sqlite3MPrintf(db, "SELECT idx, stat FROM %Q.sqlite_stat1",
+                        sInfo.zDatabase);
+  (void)sqlite3SafetyOff(db);
+  rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
+  (void)sqlite3SafetyOn(db);
+  sqlite3_free(zSql);
+  return rc;
+}
+
+
+#endif /* SQLITE_OMIT_ANALYZE */
+
+/************** End of analyze.c *********************************************/
+/************** Begin file attach.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the ATTACH and DETACH commands.
+**
+** $Id: attach.c,v 1.75 2008/04/17 17:02:01 drh Exp $
+*/
+
+#ifndef SQLITE_OMIT_ATTACH
+/*
+** Resolve an expression that was part of an ATTACH or DETACH statement. This
+** is slightly different from resolving a normal SQL expression, because simple
+** identifiers are treated as strings, not possible column names or aliases.
+**
+** i.e. if the parser sees:
+**
+**     ATTACH DATABASE abc AS def
+**
+** it treats the two expressions as literal strings 'abc' and 'def' instead of
+** looking for columns of the same name.
+**
+** This only applies to the root node of pExpr, so the statement:
+**
+**     ATTACH DATABASE abc||def AS 'db2'
+**
+** will fail because neither abc or def can be resolved.
+*/
+static int resolveAttachExpr(NameContext *pName, Expr *pExpr)
+{
+  int rc = SQLITE_OK;
+  if( pExpr ){
+    if( pExpr->op!=TK_ID ){
+      rc = sqlite3ExprResolveNames(pName, pExpr);
+      if( rc==SQLITE_OK && !sqlite3ExprIsConstant(pExpr) ){
+        sqlite3ErrorMsg(pName->pParse, "invalid name: \"%T\"", &pExpr->span);
+        return SQLITE_ERROR;
+      }
+    }else{
+      pExpr->op = TK_STRING;
+    }
+  }
+  return rc;
+}
+
+/*
+** An SQL user-function registered to do the work of an ATTACH statement. The
+** three arguments to the function come directly from an attach statement:
+**
+**     ATTACH DATABASE x AS y KEY z
+**
+**     SELECT sqlite_attach(x, y, z)
+**
+** If the optional "KEY z" syntax is omitted, an SQL NULL is passed as the
+** third argument.
+*/
+static void attachFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  int rc = 0;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  const char *zName;
+  const char *zFile;
+  Db *aNew;
+  char *zErrDyn = 0;
+  char zErr[128];
+
+  zFile = (const char *)sqlite3_value_text(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[1]);
+  if( zFile==0 ) zFile = "";
+  if( zName==0 ) zName = "";
+
+  /* Check for the following errors:
+  **
+  **     * Too many attached databases,
+  **     * Transaction currently open
+  **     * Specified database name already being used.
+  */
+  if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){
+    sqlite3_snprintf(
+      sizeof(zErr), zErr, "too many attached databases - max %d", 
+      db->aLimit[SQLITE_LIMIT_ATTACHED]
+    );
+    goto attach_error;
+  }
+  if( !db->autoCommit ){
+    sqlite3_snprintf(sizeof(zErr), zErr,
+                     "cannot ATTACH database within transaction");
+    goto attach_error;
+  }
+  for(i=0; i<db->nDb; i++){
+    char *z = db->aDb[i].zName;
+    if( z && zName && sqlite3StrICmp(z, zName)==0 ){
+      sqlite3_snprintf(sizeof(zErr), zErr, 
+                       "database %s is already in use", zName);
+      goto attach_error;
+    }
+  }
+
+  /* Allocate the new entry in the db->aDb[] array and initialise the schema
+  ** hash tables.
+  */
+  if( db->aDb==db->aDbStatic ){
+    aNew = sqlite3_malloc( sizeof(db->aDb[0])*3 );
+    if( aNew==0 ){
+      db->mallocFailed = 1;
+      return;
+    }
+    memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
+  }else{
+    aNew = sqlite3_realloc(db->aDb, sizeof(db->aDb[0])*(db->nDb+1) );
+    if( aNew==0 ){
+      db->mallocFailed = 1;
+      return;
+    } 
+  }
+  db->aDb = aNew;
+  aNew = &db->aDb[db->nDb++];
+  memset(aNew, 0, sizeof(*aNew));
+
+  /* Open the database file. If the btree is successfully opened, use
+  ** it to obtain the database schema. At this point the schema may
+  ** or may not be initialised.
+  */
+  rc = sqlite3BtreeFactory(db, zFile, 0, SQLITE_DEFAULT_CACHE_SIZE,
+                           db->openFlags | SQLITE_OPEN_MAIN_DB,
+                           &aNew->pBt);
+  if( rc==SQLITE_OK ){
+    Pager *pPager;
+    aNew->pSchema = sqlite3SchemaGet(db, aNew->pBt);
+    if( !aNew->pSchema ){
+      rc = SQLITE_NOMEM;
+    }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
+      sqlite3_snprintf(sizeof(zErr), zErr, 
+        "attached databases must use the same text encoding as main database");
+      goto attach_error;
+    }
+    pPager = sqlite3BtreePager(aNew->pBt);
+    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
+    sqlite3PagerJournalMode(pPager, db->dfltJournalMode);
+  }
+  aNew->zName = sqlite3DbStrDup(db, zName);
+  aNew->safety_level = 3;
+
+#if SQLITE_HAS_CODEC
+  {
+    extern int sqlite3CodecAttach(sqlite3*, int, const void*, int);
+    extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
+    int nKey;
+    char *zKey;
+    int t = sqlite3_value_type(argv[2]);
+    switch( t ){
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        zErrDyn = sqlite3DbStrDup(db, "Invalid key value");
+        rc = SQLITE_ERROR;
+        break;
+        
+      case SQLITE_TEXT:
+      case SQLITE_BLOB:
+        nKey = sqlite3_value_bytes(argv[2]);
+        zKey = (char *)sqlite3_value_blob(argv[2]);
+        sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
+        break;
+
+      case SQLITE_NULL:
+        /* No key specified.  Use the key from the main database */
+        sqlite3CodecGetKey(db, 0, (void**)&zKey, &nKey);
+        sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
+        break;
+    }
+  }
+#endif
+
+  /* If the file was opened successfully, read the schema for the new database.
+  ** If this fails, or if opening the file failed, then close the file and 
+  ** remove the entry from the db->aDb[] array. i.e. put everything back the way
+  ** we found it.
+  */
+  if( rc==SQLITE_OK ){
+    (void)sqlite3SafetyOn(db);
+    sqlite3BtreeEnterAll(db);
+    rc = sqlite3Init(db, &zErrDyn);
+    sqlite3BtreeLeaveAll(db);
+    (void)sqlite3SafetyOff(db);
+  }
+  if( rc ){
+    int iDb = db->nDb - 1;
+    assert( iDb>=2 );
+    if( db->aDb[iDb].pBt ){
+      sqlite3BtreeClose(db->aDb[iDb].pBt);
+      db->aDb[iDb].pBt = 0;
+      db->aDb[iDb].pSchema = 0;
+    }
+    sqlite3ResetInternalSchema(db, 0);
+    db->nDb = iDb;
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+      db->mallocFailed = 1;
+      sqlite3_snprintf(sizeof(zErr),zErr, "out of memory");
+    }else{
+      sqlite3_snprintf(sizeof(zErr),zErr, "unable to open database: %s", zFile);
+    }
+    goto attach_error;
+  }
+  
+  return;
+
+attach_error:
+  /* Return an error if we get here */
+  if( zErrDyn ){
+    sqlite3_result_error(context, zErrDyn, -1);
+    sqlite3_free(zErrDyn);
+  }else{
+    zErr[sizeof(zErr)-1] = 0;
+    sqlite3_result_error(context, zErr, -1);
+  }
+  if( rc ) sqlite3_result_error_code(context, rc);
+}
+
+/*
+** An SQL user-function registered to do the work of an DETACH statement. The
+** three arguments to the function come directly from a detach statement:
+**
+**     DETACH DATABASE x
+**
+**     SELECT sqlite_detach(x)
+*/
+static void detachFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zName = (const char *)sqlite3_value_text(argv[0]);
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int i;
+  Db *pDb = 0;
+  char zErr[128];
+
+  if( zName==0 ) zName = "";
+  for(i=0; i<db->nDb; i++){
+    pDb = &db->aDb[i];
+    if( pDb->pBt==0 ) continue;
+    if( sqlite3StrICmp(pDb->zName, zName)==0 ) break;
+  }
+
+  if( i>=db->nDb ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "no such database: %s", zName);
+    goto detach_error;
+  }
+  if( i<2 ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "cannot detach database %s", zName);
+    goto detach_error;
+  }
+  if( !db->autoCommit ){
+    sqlite3_snprintf(sizeof(zErr), zErr,
+                     "cannot DETACH database within transaction");
+    goto detach_error;
+  }
+  if( sqlite3BtreeIsInReadTrans(pDb->pBt) ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
+    goto detach_error;
+  }
+
+  sqlite3BtreeClose(pDb->pBt);
+  pDb->pBt = 0;
+  pDb->pSchema = 0;
+  sqlite3ResetInternalSchema(db, 0);
+  return;
+
+detach_error:
+  sqlite3_result_error(context, zErr, -1);
+}
+
+/*
+** This procedure generates VDBE code for a single invocation of either the
+** sqlite_detach() or sqlite_attach() SQL user functions.
+*/
+static void codeAttach(
+  Parse *pParse,       /* The parser context */
+  int type,            /* Either SQLITE_ATTACH or SQLITE_DETACH */
+  const char *zFunc,   /* Either "sqlite_attach" or "sqlite_detach */
+  int nFunc,           /* Number of args to pass to zFunc */
+  Expr *pAuthArg,      /* Expression to pass to authorization callback */
+  Expr *pFilename,     /* Name of database file */
+  Expr *pDbname,       /* Name of the database to use internally */
+  Expr *pKey           /* Database key for encryption extension */
+){
+  int rc;
+  NameContext sName;
+  Vdbe *v;
+  FuncDef *pFunc;
+  sqlite3* db = pParse->db;
+  int regArgs;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  assert( db->mallocFailed || pAuthArg );
+  if( pAuthArg ){
+    char *zAuthArg = sqlite3NameFromToken(db, &pAuthArg->span);
+    if( !zAuthArg ){
+      goto attach_end;
+    }
+    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
+    sqlite3_free(zAuthArg);
+    if(rc!=SQLITE_OK ){
+      goto attach_end;
+    }
+  }
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+  memset(&sName, 0, sizeof(NameContext));
+  sName.pParse = pParse;
+
+  if( 
+      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pFilename)) ||
+      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pDbname)) ||
+      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
+  ){
+    pParse->nErr++;
+    goto attach_end;
+  }
+
+  v = sqlite3GetVdbe(pParse);
+  regArgs = sqlite3GetTempRange(pParse, 4);
+  sqlite3ExprCode(pParse, pFilename, regArgs);
+  sqlite3ExprCode(pParse, pDbname, regArgs+1);
+  sqlite3ExprCode(pParse, pKey, regArgs+2);
+
+  assert( v || db->mallocFailed );
+  if( v ){
+    sqlite3VdbeAddOp3(v, OP_Function, 0, regArgs+3-nFunc, regArgs+3);
+    sqlite3VdbeChangeP5(v, nFunc);
+    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
+    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);
+
+    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
+    ** statement only). For DETACH, set it to false (expire all existing
+    ** statements).
+    */
+    sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH));
+  }
+  
+attach_end:
+  sqlite3ExprDelete(pFilename);
+  sqlite3ExprDelete(pDbname);
+  sqlite3ExprDelete(pKey);
+}
+
+/*
+** Called by the parser to compile a DETACH statement.
+**
+**     DETACH pDbname
+*/
+SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
+  codeAttach(pParse, SQLITE_DETACH, "sqlite_detach", 1, pDbname, 0, 0, pDbname);
+}
+
+/*
+** Called by the parser to compile an ATTACH statement.
+**
+**     ATTACH p AS pDbname KEY pKey
+*/
+SQLITE_PRIVATE void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){
+  codeAttach(pParse, SQLITE_ATTACH, "sqlite_attach", 3, p, p, pDbname, pKey);
+}
+#endif /* SQLITE_OMIT_ATTACH */
+
+/*
+** Register the functions sqlite_attach and sqlite_detach.
+*/
+SQLITE_PRIVATE void sqlite3AttachFunctions(sqlite3 *db){
+#ifndef SQLITE_OMIT_ATTACH
+  static const int enc = SQLITE_UTF8;
+  sqlite3CreateFunc(db, "sqlite_attach", 3, enc, 0, attachFunc, 0, 0);
+  sqlite3CreateFunc(db, "sqlite_detach", 1, enc, 0, detachFunc, 0, 0);
+#endif
+}
+
+/*
+** Initialize a DbFixer structure.  This routine must be called prior
+** to passing the structure to one of the sqliteFixAAAA() routines below.
+**
+** The return value indicates whether or not fixation is required.  TRUE
+** means we do need to fix the database references, FALSE means we do not.
+*/
+SQLITE_PRIVATE int sqlite3FixInit(
+  DbFixer *pFix,      /* The fixer to be initialized */
+  Parse *pParse,      /* Error messages will be written here */
+  int iDb,            /* This is the database that must be used */
+  const char *zType,  /* "view", "trigger", or "index" */
+  const Token *pName  /* Name of the view, trigger, or index */
+){
+  sqlite3 *db;
+
+  if( iDb<0 || iDb==1 ) return 0;
+  db = pParse->db;
+  assert( db->nDb>iDb );
+  pFix->pParse = pParse;
+  pFix->zDb = db->aDb[iDb].zName;
+  pFix->zType = zType;
+  pFix->pName = pName;
+  return 1;
+}
+
+/*
+** The following set of routines walk through the parse tree and assign
+** a specific database to all table references where the database name
+** was left unspecified in the original SQL statement.  The pFix structure
+** must have been initialized by a prior call to sqlite3FixInit().
+**
+** These routines are used to make sure that an index, trigger, or
+** view in one database does not refer to objects in a different database.
+** (Exception: indices, triggers, and views in the TEMP database are
+** allowed to refer to anything.)  If a reference is explicitly made
+** to an object in a different database, an error message is added to
+** pParse->zErrMsg and these routines return non-zero.  If everything
+** checks out, these routines return 0.
+*/
+SQLITE_PRIVATE int sqlite3FixSrcList(
+  DbFixer *pFix,       /* Context of the fixation */
+  SrcList *pList       /* The Source list to check and modify */
+){
+  int i;
+  const char *zDb;
+  struct SrcList_item *pItem;
+
+  if( pList==0 ) return 0;
+  zDb = pFix->zDb;
+  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+    if( pItem->zDatabase==0 ){
+      pItem->zDatabase = sqlite3DbStrDup(pFix->pParse->db, zDb);
+    }else if( sqlite3StrICmp(pItem->zDatabase,zDb)!=0 ){
+      sqlite3ErrorMsg(pFix->pParse,
+         "%s %T cannot reference objects in database %s",
+         pFix->zType, pFix->pName, pItem->zDatabase);
+      return 1;
+    }
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+    if( sqlite3FixSelect(pFix, pItem->pSelect) ) return 1;
+    if( sqlite3FixExpr(pFix, pItem->pOn) ) return 1;
+#endif
+  }
+  return 0;
+}
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE int sqlite3FixSelect(
+  DbFixer *pFix,       /* Context of the fixation */
+  Select *pSelect      /* The SELECT statement to be fixed to one database */
+){
+  while( pSelect ){
+    if( sqlite3FixExprList(pFix, pSelect->pEList) ){
+      return 1;
+    }
+    if( sqlite3FixSrcList(pFix, pSelect->pSrc) ){
+      return 1;
+    }
+    if( sqlite3FixExpr(pFix, pSelect->pWhere) ){
+      return 1;
+    }
+    if( sqlite3FixExpr(pFix, pSelect->pHaving) ){
+      return 1;
+    }
+    pSelect = pSelect->pPrior;
+  }
+  return 0;
+}
+SQLITE_PRIVATE int sqlite3FixExpr(
+  DbFixer *pFix,     /* Context of the fixation */
+  Expr *pExpr        /* The expression to be fixed to one database */
+){
+  while( pExpr ){
+    if( sqlite3FixSelect(pFix, pExpr->pSelect) ){
+      return 1;
+    }
+    if( sqlite3FixExprList(pFix, pExpr->pList) ){
+      return 1;
+    }
+    if( sqlite3FixExpr(pFix, pExpr->pRight) ){
+      return 1;
+    }
+    pExpr = pExpr->pLeft;
+  }
+  return 0;
+}
+SQLITE_PRIVATE int sqlite3FixExprList(
+  DbFixer *pFix,     /* Context of the fixation */
+  ExprList *pList    /* The expression to be fixed to one database */
+){
+  int i;
+  struct ExprList_item *pItem;
+  if( pList==0 ) return 0;
+  for(i=0, pItem=pList->a; i<pList->nExpr; i++, pItem++){
+    if( sqlite3FixExpr(pFix, pItem->pExpr) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE int sqlite3FixTriggerStep(
+  DbFixer *pFix,     /* Context of the fixation */
+  TriggerStep *pStep /* The trigger step be fixed to one database */
+){
+  while( pStep ){
+    if( sqlite3FixSelect(pFix, pStep->pSelect) ){
+      return 1;
+    }
+    if( sqlite3FixExpr(pFix, pStep->pWhere) ){
+      return 1;
+    }
+    if( sqlite3FixExprList(pFix, pStep->pExprList) ){
+      return 1;
+    }
+    pStep = pStep->pNext;
+  }
+  return 0;
+}
+#endif
+
+/************** End of attach.c **********************************************/
+/************** Begin file auth.c ********************************************/
+/*
+** 2003 January 11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the sqlite3_set_authorizer()
+** API.  This facility is an optional feature of the library.  Embedded
+** systems that do not need this facility may omit it by recompiling
+** the library with -DSQLITE_OMIT_AUTHORIZATION=1
+**
+** $Id: auth.c,v 1.29 2007/09/18 15:55:07 drh Exp $
+*/
+
+/*
+** All of the code in this file may be omitted by defining a single
+** macro.
+*/
+#ifndef SQLITE_OMIT_AUTHORIZATION
+
+/*
+** Set or clear the access authorization function.
+**
+** The access authorization function is be called during the compilation
+** phase to verify that the user has read and/or write access permission on
+** various fields of the database.  The first argument to the auth function
+** is a copy of the 3rd argument to this routine.  The second argument
+** to the auth function is one of these constants:
+**
+**       SQLITE_CREATE_INDEX
+**       SQLITE_CREATE_TABLE
+**       SQLITE_CREATE_TEMP_INDEX
+**       SQLITE_CREATE_TEMP_TABLE
+**       SQLITE_CREATE_TEMP_TRIGGER
+**       SQLITE_CREATE_TEMP_VIEW
+**       SQLITE_CREATE_TRIGGER
+**       SQLITE_CREATE_VIEW
+**       SQLITE_DELETE
+**       SQLITE_DROP_INDEX
+**       SQLITE_DROP_TABLE
+**       SQLITE_DROP_TEMP_INDEX
+**       SQLITE_DROP_TEMP_TABLE
+**       SQLITE_DROP_TEMP_TRIGGER
+**       SQLITE_DROP_TEMP_VIEW
+**       SQLITE_DROP_TRIGGER
+**       SQLITE_DROP_VIEW
+**       SQLITE_INSERT
+**       SQLITE_PRAGMA
+**       SQLITE_READ
+**       SQLITE_SELECT
+**       SQLITE_TRANSACTION
+**       SQLITE_UPDATE
+**
+** The third and fourth arguments to the auth function are the name of
+** the table and the column that are being accessed.  The auth function
+** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE.  If
+** SQLITE_OK is returned, it means that access is allowed.  SQLITE_DENY
+** means that the SQL statement will never-run - the sqlite3_exec() call
+** will return with an error.  SQLITE_IGNORE means that the SQL statement
+** should run but attempts to read the specified column will return NULL
+** and attempts to write the column will be ignored.
+**
+** Setting the auth function to NULL disables this hook.  The default
+** setting of the auth function is NULL.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3 *db,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pArg
+){
+  sqlite3_mutex_enter(db->mutex);
+  db->xAuth = xAuth;
+  db->pAuthArg = pArg;
+  sqlite3ExpirePreparedStatements(db);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Write an error message into pParse->zErrMsg that explains that the
+** user-supplied authorization function returned an illegal value.
+*/
+static void sqliteAuthBadReturnCode(Parse *pParse, int rc){
+  sqlite3ErrorMsg(pParse, "illegal return value (%d) from the "
+    "authorization function - should be SQLITE_OK, SQLITE_IGNORE, "
+    "or SQLITE_DENY", rc);
+  pParse->rc = SQLITE_ERROR;
+}
+
+/*
+** The pExpr should be a TK_COLUMN expression.  The table referred to
+** is in pTabList or else it is the NEW or OLD table of a trigger.  
+** Check to see if it is OK to read this particular column.
+**
+** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN 
+** instruction into a TK_NULL.  If the auth function returns SQLITE_DENY,
+** then generate an error.
+*/
+SQLITE_PRIVATE void sqlite3AuthRead(
+  Parse *pParse,        /* The parser context */
+  Expr *pExpr,          /* The expression to check authorization on */
+  Schema *pSchema,      /* The schema of the expression */
+  SrcList *pTabList     /* All table that pExpr might refer to */
+){
+  sqlite3 *db = pParse->db;
+  int rc;
+  Table *pTab = 0;      /* The table being read */
+  const char *zCol;     /* Name of the column of the table */
+  int iSrc;             /* Index in pTabList->a[] of table being read */
+  const char *zDBase;   /* Name of database being accessed */
+  TriggerStack *pStack; /* The stack of current triggers */
+  int iDb;              /* The index of the database the expression refers to */
+
+  if( db->xAuth==0 ) return;
+  if( pExpr->op!=TK_COLUMN ) return;
+  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
+  if( iDb<0 ){
+    /* An attempt to read a column out of a subquery or other
+    ** temporary table. */
+    return;
+  }
+  for(iSrc=0; pTabList && iSrc<pTabList->nSrc; iSrc++){
+    if( pExpr->iTable==pTabList->a[iSrc].iCursor ) break;
+  }
+  if( iSrc>=0 && pTabList && iSrc<pTabList->nSrc ){
+    pTab = pTabList->a[iSrc].pTab;
+  }else if( (pStack = pParse->trigStack)!=0 ){
+    /* This must be an attempt to read the NEW or OLD pseudo-tables
+    ** of a trigger.
+    */
+    assert( pExpr->iTable==pStack->newIdx || pExpr->iTable==pStack->oldIdx );
+    pTab = pStack->pTab;
+  }
+  if( pTab==0 ) return;
+  if( pExpr->iColumn>=0 ){
+    assert( pExpr->iColumn<pTab->nCol );
+    zCol = pTab->aCol[pExpr->iColumn].zName;
+  }else if( pTab->iPKey>=0 ){
+    assert( pTab->iPKey<pTab->nCol );
+    zCol = pTab->aCol[pTab->iPKey].zName;
+  }else{
+    zCol = "ROWID";
+  }
+  assert( iDb>=0 && iDb<db->nDb );
+  zDBase = db->aDb[iDb].zName;
+  rc = db->xAuth(db->pAuthArg, SQLITE_READ, pTab->zName, zCol, zDBase, 
+                 pParse->zAuthContext);
+  if( rc==SQLITE_IGNORE ){
+    pExpr->op = TK_NULL;
+  }else if( rc==SQLITE_DENY ){
+    if( db->nDb>2 || iDb!=0 ){
+      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited", 
+         zDBase, pTab->zName, zCol);
+    }else{
+      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited",pTab->zName,zCol);
+    }
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_OK ){
+    sqliteAuthBadReturnCode(pParse, rc);
+  }
+}
+
+/*
+** Do an authorization check using the code and arguments given.  Return
+** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
+** is returned, then the error count and error message in pParse are
+** modified appropriately.
+*/
+SQLITE_PRIVATE int sqlite3AuthCheck(
+  Parse *pParse,
+  int code,
+  const char *zArg1,
+  const char *zArg2,
+  const char *zArg3
+){
+  sqlite3 *db = pParse->db;
+  int rc;
+
+  /* Don't do any authorization checks if the database is initialising
+  ** or if the parser is being invoked from within sqlite3_declare_vtab.
+  */
+  if( db->init.busy || IN_DECLARE_VTAB ){
+    return SQLITE_OK;
+  }
+
+  if( db->xAuth==0 ){
+    return SQLITE_OK;
+  }
+  rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    sqlite3ErrorMsg(pParse, "not authorized");
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
+    rc = SQLITE_DENY;
+    sqliteAuthBadReturnCode(pParse, rc);
+  }
+  return rc;
+}
+
+/*
+** Push an authorization context.  After this routine is called, the
+** zArg3 argument to authorization callbacks will be zContext until
+** popped.  Or if pParse==0, this routine is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPush(
+  Parse *pParse,
+  AuthContext *pContext, 
+  const char *zContext
+){
+  pContext->pParse = pParse;
+  if( pParse ){
+    pContext->zAuthContext = pParse->zAuthContext;
+    pParse->zAuthContext = zContext;
+  }
+}
+
+/*
+** Pop an authorization context that was previously pushed
+** by sqlite3AuthContextPush
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPop(AuthContext *pContext){
+  if( pContext->pParse ){
+    pContext->pParse->zAuthContext = pContext->zAuthContext;
+    pContext->pParse = 0;
+  }
+}
+
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+/************** End of auth.c ************************************************/
+/************** Begin file build.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the SQLite parser
+** when syntax rules are reduced.  The routines in this file handle the
+** following kinds of SQL syntax:
+**
+**     CREATE TABLE
+**     DROP TABLE
+**     CREATE INDEX
+**     DROP INDEX
+**     creating ID lists
+**     BEGIN TRANSACTION
+**     COMMIT
+**     ROLLBACK
+**
+** $Id: build.c,v 1.484 2008/05/01 17:16:53 drh Exp $
+*/
+
+/*
+** This routine is called when a new SQL statement is beginning to
+** be parsed.  Initialize the pParse structure as needed.
+*/
+SQLITE_PRIVATE void sqlite3BeginParse(Parse *pParse, int explainFlag){
+  pParse->explain = explainFlag;
+  pParse->nVar = 0;
+}
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** The TableLock structure is only used by the sqlite3TableLock() and
+** codeTableLocks() functions.
+*/
+struct TableLock {
+  int iDb;             /* The database containing the table to be locked */
+  int iTab;            /* The root page of the table to be locked */
+  u8 isWriteLock;      /* True for write lock.  False for a read lock */
+  const char *zName;   /* Name of the table */
+};
+
+/*
+** Record the fact that we want to lock a table at run-time.  
+**
+** The table to be locked has root page iTab and is found in database iDb.
+** A read or a write lock can be taken depending on isWritelock.
+**
+** This routine just records the fact that the lock is desired.  The
+** code to make the lock occur is generated by a later call to
+** codeTableLocks() which occurs during sqlite3FinishCoding().
+*/
+SQLITE_PRIVATE void sqlite3TableLock(
+  Parse *pParse,     /* Parsing context */
+  int iDb,           /* Index of the database containing the table to lock */
+  int iTab,          /* Root page number of the table to be locked */
+  u8 isWriteLock,    /* True for a write lock */
+  const char *zName  /* Name of the table to be locked */
+){
+  int i;
+  int nBytes;
+  TableLock *p;
+
+  if( iDb<0 ){
+    return;
+  }
+
+  for(i=0; i<pParse->nTableLock; i++){
+    p = &pParse->aTableLock[i];
+    if( p->iDb==iDb && p->iTab==iTab ){
+      p->isWriteLock = (p->isWriteLock || isWriteLock);
+      return;
+    }
+  }
+
+  nBytes = sizeof(TableLock) * (pParse->nTableLock+1);
+  pParse->aTableLock = 
+      sqlite3DbReallocOrFree(pParse->db, pParse->aTableLock, nBytes);
+  if( pParse->aTableLock ){
+    p = &pParse->aTableLock[pParse->nTableLock++];
+    p->iDb = iDb;
+    p->iTab = iTab;
+    p->isWriteLock = isWriteLock;
+    p->zName = zName;
+  }else{
+    pParse->nTableLock = 0;
+    pParse->db->mallocFailed = 1;
+  }
+}
+
+/*
+** Code an OP_TableLock instruction for each table locked by the
+** statement (configured by calls to sqlite3TableLock()).
+*/
+static void codeTableLocks(Parse *pParse){
+  int i;
+  Vdbe *pVdbe; 
+
+  if( 0==(pVdbe = sqlite3GetVdbe(pParse)) ){
+    return;
+  }
+
+  for(i=0; i<pParse->nTableLock; i++){
+    TableLock *p = &pParse->aTableLock[i];
+    int p1 = p->iDb;
+    sqlite3VdbeAddOp4(pVdbe, OP_TableLock, p1, p->iTab, p->isWriteLock,
+                      p->zName, P4_STATIC);
+  }
+}
+#else
+  #define codeTableLocks(x)
+#endif
+
+/*
+** This routine is called after a single SQL statement has been
+** parsed and a VDBE program to execute that statement has been
+** prepared.  This routine puts the finishing touches on the
+** VDBE program and resets the pParse structure for the next
+** parse.
+**
+** Note that if an error occurred, it might be the case that
+** no VDBE code was generated.
+*/
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
+  sqlite3 *db;
+  Vdbe *v;
+
+  db = pParse->db;
+  if( db->mallocFailed ) return;
+  if( pParse->nested ) return;
+  if( pParse->nErr ) return;
+  if( !pParse->pVdbe ){
+    if( pParse->rc==SQLITE_OK && pParse->nErr ){
+      pParse->rc = SQLITE_ERROR;
+      return;
+    }
+  }
+
+  /* Begin by generating some termination code at the end of the
+  ** vdbe program
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp0(v, OP_Halt);
+
+    /* The cookie mask contains one bit for each database file open.
+    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
+    ** set for each database that is used.  Generate code to start a
+    ** transaction on each used database and to verify the schema cookie
+    ** on each used database.
+    */
+    if( pParse->cookieGoto>0 ){
+      u32 mask;
+      int iDb;
+      sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
+      for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
+        if( (mask & pParse->cookieMask)==0 ) continue;
+        sqlite3VdbeUsesBtree(v, iDb);
+        sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
+        sqlite3VdbeAddOp2(v,OP_VerifyCookie, iDb, pParse->cookieValue[iDb]);
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      {
+        int i;
+        for(i=0; i<pParse->nVtabLock; i++){
+          char *vtab = (char *)pParse->apVtabLock[i]->pVtab;
+          sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
+        }
+        pParse->nVtabLock = 0;
+      }
+#endif
+
+      /* Once all the cookies have been verified and transactions opened, 
+      ** obtain the required table-locks. This is a no-op unless the 
+      ** shared-cache feature is enabled.
+      */
+      codeTableLocks(pParse);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->cookieGoto);
+    }
+
+#ifndef SQLITE_OMIT_TRACE
+    if( !db->init.busy ){
+      /* Change the P4 argument of the first opcode (which will always be
+      ** an OP_Trace) to be the complete text of the current SQL statement.
+      */
+      VdbeOp *pOp = sqlite3VdbeGetOp(v, 0);
+      if( pOp && pOp->opcode==OP_Trace ){
+        sqlite3VdbeChangeP4(v, 0, pParse->zSql, pParse->zTail-pParse->zSql);
+      }
+    }
+#endif /* SQLITE_OMIT_TRACE */
+  }
+
+
+  /* Get the VDBE program ready for execution
+  */
+  if( v && pParse->nErr==0 && !db->mallocFailed ){
+#ifdef SQLITE_DEBUG
+    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
+    sqlite3VdbeTrace(v, trace);
+#endif
+    assert( pParse->disableColCache==0 );  /* Disables and re-enables match */
+    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem+3,
+                         pParse->nTab+3, pParse->explain);
+    pParse->rc = SQLITE_DONE;
+    pParse->colNamesSet = 0;
+  }else if( pParse->rc==SQLITE_OK ){
+    pParse->rc = SQLITE_ERROR;
+  }
+  pParse->nTab = 0;
+  pParse->nMem = 0;
+  pParse->nSet = 0;
+  pParse->nVar = 0;
+  pParse->cookieMask = 0;
+  pParse->cookieGoto = 0;
+}
+
+/*
+** Run the parser and code generator recursively in order to generate
+** code for the SQL statement given onto the end of the pParse context
+** currently under construction.  When the parser is run recursively
+** this way, the final OP_Halt is not appended and other initialization
+** and finalization steps are omitted because those are handling by the
+** outermost parser.
+**
+** Not everything is nestable.  This facility is designed to permit
+** INSERT, UPDATE, and DELETE operations against SQLITE_MASTER.  Use
+** care if you decide to try to use this routine for some other purposes.
+*/
+SQLITE_PRIVATE void sqlite3NestedParse(Parse *pParse, const char *zFormat, ...){
+  va_list ap;
+  char *zSql;
+# define SAVE_SZ  (sizeof(Parse) - offsetof(Parse,nVar))
+  char saveBuf[SAVE_SZ];
+
+  if( pParse->nErr ) return;
+  assert( pParse->nested<10 );  /* Nesting should only be of limited depth */
+  va_start(ap, zFormat);
+  zSql = sqlite3VMPrintf(pParse->db, zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    pParse->db->mallocFailed = 1;
+    return;   /* A malloc must have failed */
+  }
+  pParse->nested++;
+  memcpy(saveBuf, &pParse->nVar, SAVE_SZ);
+  memset(&pParse->nVar, 0, SAVE_SZ);
+  sqlite3RunParser(pParse, zSql, 0);
+  sqlite3_free(zSql);
+  memcpy(&pParse->nVar, saveBuf, SAVE_SZ);
+  pParse->nested--;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the table and the
+** first matching table is returned.  (No checking for duplicate table
+** names is done.)  The search order is TEMP first, then MAIN, then any
+** auxiliary databases added using the ATTACH command.
+**
+** See also sqlite3LocateTable().
+*/
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
+  Table *p = 0;
+  int i;
+  assert( zName!=0 );
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
+    if( zDatabase!=0 && sqlite3StrICmp(zDatabase, db->aDb[j].zName) ) continue;
+    p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName, strlen(zName)+1);
+    if( p ) break;
+  }
+  return p;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.  Also leave an
+** error message in pParse->zErrMsg.
+**
+** The difference between this routine and sqlite3FindTable() is that this
+** routine leaves an error message in pParse->zErrMsg where
+** sqlite3FindTable() does not.
+*/
+SQLITE_PRIVATE Table *sqlite3LocateTable(
+  Parse *pParse,         /* context in which to report errors */
+  int isView,            /* True if looking for a VIEW rather than a TABLE */
+  const char *zName,     /* Name of the table we are looking for */
+  const char *zDbase     /* Name of the database.  Might be NULL */
+){
+  Table *p;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return 0;
+  }
+
+  p = sqlite3FindTable(pParse->db, zName, zDbase);
+  if( p==0 ){
+    const char *zMsg = isView ? "no such view" : "no such table";
+    if( zDbase ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
+    }
+    pParse->checkSchema = 1;
+  }
+  return p;
+}
+
+/*
+** Locate the in-memory structure that describes 
+** a particular index given the name of that index
+** and the name of the database that contains the index.
+** Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the
+** table and the first matching index is returned.  (No checking
+** for duplicate index names is done.)  The search order is
+** TEMP first, then MAIN, then any auxiliary databases added
+** using the ATTACH command.
+*/
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
+  Index *p = 0;
+  int i;
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    Schema *pSchema = db->aDb[j].pSchema;
+    if( zDb && sqlite3StrICmp(zDb, db->aDb[j].zName) ) continue;
+    assert( pSchema || (j==1 && !db->aDb[1].pBt) );
+    if( pSchema ){
+      p = sqlite3HashFind(&pSchema->idxHash, zName, strlen(zName)+1);
+    }
+    if( p ) break;
+  }
+  return p;
+}
+
+/*
+** Reclaim the memory used by an index
+*/
+static void freeIndex(Index *p){
+  sqlite3_free(p->zColAff);
+  sqlite3_free(p);
+}
+
+/*
+** Remove the given index from the index hash table, and free
+** its memory structures.
+**
+** The index is removed from the database hash tables but
+** it is not unlinked from the Table that it indexes.
+** Unlinking from the Table must be done by the calling function.
+*/
+static void sqliteDeleteIndex(Index *p){
+  Index *pOld;
+  const char *zName = p->zName;
+
+  pOld = sqlite3HashInsert(&p->pSchema->idxHash, zName, strlen( zName)+1, 0);
+  assert( pOld==0 || pOld==p );
+  freeIndex(p);
+}
+
+/*
+** For the index called zIdxName which is found in the database iDb,
+** unlike that index from its Table then remove the index from
+** the index hash table and free all memory structures associated
+** with the index.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){
+  Index *pIndex;
+  int len;
+  Hash *pHash = &db->aDb[iDb].pSchema->idxHash;
+
+  len = strlen(zIdxName);
+  pIndex = sqlite3HashInsert(pHash, zIdxName, len+1, 0);
+  if( pIndex ){
+    if( pIndex->pTable->pIndex==pIndex ){
+      pIndex->pTable->pIndex = pIndex->pNext;
+    }else{
+      Index *p;
+      for(p=pIndex->pTable->pIndex; p && p->pNext!=pIndex; p=p->pNext){}
+      if( p && p->pNext==pIndex ){
+        p->pNext = pIndex->pNext;
+      }
+    }
+    freeIndex(pIndex);
+  }
+  db->flags |= SQLITE_InternChanges;
+}
+
+/*
+** Erase all schema information from the in-memory hash tables of
+** a single database.  This routine is called to reclaim memory
+** before the database closes.  It is also called during a rollback
+** if there were schema changes during the transaction or if a
+** schema-cookie mismatch occurs.
+**
+** If iDb<=0 then reset the internal schema tables for all database
+** files.  If iDb>=2 then reset the internal schema for only the
+** single file indicated.
+*/
+SQLITE_PRIVATE void sqlite3ResetInternalSchema(sqlite3 *db, int iDb){
+  int i, j;
+  assert( iDb>=0 && iDb<db->nDb );
+
+  if( iDb==0 ){
+    sqlite3BtreeEnterAll(db);
+  }
+  for(i=iDb; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pSchema ){
+      assert(i==1 || (pDb->pBt && sqlite3BtreeHoldsMutex(pDb->pBt)));
+      sqlite3SchemaFree(pDb->pSchema);
+    }
+    if( iDb>0 ) return;
+  }
+  assert( iDb==0 );
+  db->flags &= ~SQLITE_InternChanges;
+  sqlite3BtreeLeaveAll(db);
+
+  /* If one or more of the auxiliary database files has been closed,
+  ** then remove them from the auxiliary database list.  We take the
+  ** opportunity to do this here since we have just deleted all of the
+  ** schema hash tables and therefore do not have to make any changes
+  ** to any of those tables.
+  */
+  for(i=0; i<db->nDb; i++){
+    struct Db *pDb = &db->aDb[i];
+    if( pDb->pBt==0 ){
+      if( pDb->pAux && pDb->xFreeAux ) pDb->xFreeAux(pDb->pAux);
+      pDb->pAux = 0;
+    }
+  }
+  for(i=j=2; i<db->nDb; i++){
+    struct Db *pDb = &db->aDb[i];
+    if( pDb->pBt==0 ){
+      sqlite3_free(pDb->zName);
+      pDb->zName = 0;
+      continue;
+    }
+    if( j<i ){
+      db->aDb[j] = db->aDb[i];
+    }
+    j++;
+  }
+  memset(&db->aDb[j], 0, (db->nDb-j)*sizeof(db->aDb[j]));
+  db->nDb = j;
+  if( db->nDb<=2 && db->aDb!=db->aDbStatic ){
+    memcpy(db->aDbStatic, db->aDb, 2*sizeof(db->aDb[0]));
+    sqlite3_free(db->aDb);
+    db->aDb = db->aDbStatic;
+  }
+}
+
+/*
+** This routine is called when a commit occurs.
+*/
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3 *db){
+  db->flags &= ~SQLITE_InternChanges;
+}
+
+/*
+** Clear the column names from a table or view.
+*/
+static void sqliteResetColumnNames(Table *pTable){
+  int i;
+  Column *pCol;
+  assert( pTable!=0 );
+  if( (pCol = pTable->aCol)!=0 ){
+    for(i=0; i<pTable->nCol; i++, pCol++){
+      sqlite3_free(pCol->zName);
+      sqlite3ExprDelete(pCol->pDflt);
+      sqlite3_free(pCol->zType);
+      sqlite3_free(pCol->zColl);
+    }
+    sqlite3_free(pTable->aCol);
+  }
+  pTable->aCol = 0;
+  pTable->nCol = 0;
+}
+
+/*
+** Remove the memory data structures associated with the given
+** Table.  No changes are made to disk by this routine.
+**
+** This routine just deletes the data structure.  It does not unlink
+** the table data structure from the hash table.  Nor does it remove
+** foreign keys from the sqlite.aFKey hash table.  But it does destroy
+** memory structures of the indices and foreign keys associated with 
+** the table.
+*/
+SQLITE_PRIVATE void sqlite3DeleteTable(Table *pTable){
+  Index *pIndex, *pNext;
+  FKey *pFKey, *pNextFKey;
+
+  if( pTable==0 ) return;
+
+  /* Do not delete the table until the reference count reaches zero. */
+  pTable->nRef--;
+  if( pTable->nRef>0 ){
+    return;
+  }
+  assert( pTable->nRef==0 );
+
+  /* Delete all indices associated with this table
+  */
+  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
+    pNext = pIndex->pNext;
+    assert( pIndex->pSchema==pTable->pSchema );
+    sqliteDeleteIndex(pIndex);
+  }
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  /* Delete all foreign keys associated with this table.  The keys
+  ** should have already been unlinked from the pSchema->aFKey hash table 
+  */
+  for(pFKey=pTable->pFKey; pFKey; pFKey=pNextFKey){
+    pNextFKey = pFKey->pNextFrom;
+    assert( sqlite3HashFind(&pTable->pSchema->aFKey,
+                           pFKey->zTo, strlen(pFKey->zTo)+1)!=pFKey );
+    sqlite3_free(pFKey);
+  }
+#endif
+
+  /* Delete the Table structure itself.
+  */
+  sqliteResetColumnNames(pTable);
+  sqlite3_free(pTable->zName);
+  sqlite3_free(pTable->zColAff);
+  sqlite3SelectDelete(pTable->pSelect);
+#ifndef SQLITE_OMIT_CHECK
+  sqlite3ExprDelete(pTable->pCheck);
+#endif
+  sqlite3VtabClear(pTable);
+  sqlite3_free(pTable);
+}
+
+/*
+** Unlink the given table from the hash tables and the delete the
+** table structure with all its indices and foreign keys.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3 *db, int iDb, const char *zTabName){
+  Table *p;
+  FKey *pF1, *pF2;
+  Db *pDb;
+
+  assert( db!=0 );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( zTabName && zTabName[0] );
+  pDb = &db->aDb[iDb];
+  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, strlen(zTabName)+1,0);
+  if( p ){
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+    for(pF1=p->pFKey; pF1; pF1=pF1->pNextFrom){
+      int nTo = strlen(pF1->zTo) + 1;
+      pF2 = sqlite3HashFind(&pDb->pSchema->aFKey, pF1->zTo, nTo);
+      if( pF2==pF1 ){
+        sqlite3HashInsert(&pDb->pSchema->aFKey, pF1->zTo, nTo, pF1->pNextTo);
+      }else{
+        while( pF2 && pF2->pNextTo!=pF1 ){ pF2=pF2->pNextTo; }
+        if( pF2 ){
+          pF2->pNextTo = pF1->pNextTo;
+        }
+      }
+    }
+#endif
+    sqlite3DeleteTable(p);
+  }
+  db->flags |= SQLITE_InternChanges;
+}
+
+/*
+** Given a token, return a string that consists of the text of that
+** token with any quotations removed.  Space to hold the returned string
+** is obtained from sqliteMalloc() and must be freed by the calling
+** function.
+**
+** Tokens are often just pointers into the original SQL text and so
+** are not \000 terminated and are not persistent.  The returned string
+** is \000 terminated and is persistent.
+*/
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3 *db, Token *pName){
+  char *zName;
+  if( pName ){
+    zName = sqlite3DbStrNDup(db, (char*)pName->z, pName->n);
+    sqlite3Dequote(zName);
+  }else{
+    zName = 0;
+  }
+  return zName;
+}
+
+/*
+** Open the sqlite_master table stored in database number iDb for
+** writing. The table is opened using cursor 0.
+*/
+SQLITE_PRIVATE void sqlite3OpenMasterTable(Parse *p, int iDb){
+  Vdbe *v = sqlite3GetVdbe(p);
+  sqlite3TableLock(p, iDb, MASTER_ROOT, 1, SCHEMA_TABLE(iDb));
+  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, 5);/* sqlite_master has 5 columns */
+  sqlite3VdbeAddOp3(v, OP_OpenWrite, 0, MASTER_ROOT, iDb);
+}
+
+/*
+** The token *pName contains the name of a database (either "main" or
+** "temp" or the name of an attached db). This routine returns the
+** index of the named database in db->aDb[], or -1 if the named db 
+** does not exist.
+*/
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3 *db, Token *pName){
+  int i = -1;    /* Database number */
+  int n;         /* Number of characters in the name */
+  Db *pDb;       /* A database whose name space is being searched */
+  char *zName;   /* Name we are searching for */
+
+  zName = sqlite3NameFromToken(db, pName);
+  if( zName ){
+    n = strlen(zName);
+    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
+      if( (!OMIT_TEMPDB || i!=1 ) && n==strlen(pDb->zName) && 
+          0==sqlite3StrICmp(pDb->zName, zName) ){
+        break;
+      }
+    }
+    sqlite3_free(zName);
+  }
+  return i;
+}
+
+/* The table or view or trigger name is passed to this routine via tokens
+** pName1 and pName2. If the table name was fully qualified, for example:
+**
+** CREATE TABLE xxx.yyy (...);
+** 
+** Then pName1 is set to "xxx" and pName2 "yyy". On the other hand if
+** the table name is not fully qualified, i.e.:
+**
+** CREATE TABLE yyy(...);
+**
+** Then pName1 is set to "yyy" and pName2 is "".
+**
+** This routine sets the *ppUnqual pointer to point at the token (pName1 or
+** pName2) that stores the unqualified table name.  The index of the
+** database "xxx" is returned.
+*/
+SQLITE_PRIVATE int sqlite3TwoPartName(
+  Parse *pParse,      /* Parsing and code generating context */
+  Token *pName1,      /* The "xxx" in the name "xxx.yyy" or "xxx" */
+  Token *pName2,      /* The "yyy" in the name "xxx.yyy" */
+  Token **pUnqual     /* Write the unqualified object name here */
+){
+  int iDb;                    /* Database holding the object */
+  sqlite3 *db = pParse->db;
+
+  if( pName2 && pName2->n>0 ){
+    assert( !db->init.busy );
+    *pUnqual = pName2;
+    iDb = sqlite3FindDb(db, pName1);
+    if( iDb<0 ){
+      sqlite3ErrorMsg(pParse, "unknown database %T", pName1);
+      pParse->nErr++;
+      return -1;
+    }
+  }else{
+    assert( db->init.iDb==0 || db->init.busy );
+    iDb = db->init.iDb;
+    *pUnqual = pName1;
+  }
+  return iDb;
+}
+
+/*
+** This routine is used to check if the UTF-8 string zName is a legal
+** unqualified name for a new schema object (table, index, view or
+** trigger). All names are legal except those that begin with the string
+** "sqlite_" (in upper, lower or mixed case). This portion of the namespace
+** is reserved for internal use.
+*/
+SQLITE_PRIVATE int sqlite3CheckObjectName(Parse *pParse, const char *zName){
+  if( !pParse->db->init.busy && pParse->nested==0 
+          && (pParse->db->flags & SQLITE_WriteSchema)==0
+          && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
+    sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s", zName);
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Begin constructing a new table representation in memory.  This is
+** the first of several action routines that get called in response
+** to a CREATE TABLE statement.  In particular, this routine is called
+** after seeing tokens "CREATE" and "TABLE" and the table name. The isTemp
+** flag is true if the table should be stored in the auxiliary database
+** file instead of in the main database file.  This is normally the case
+** when the "TEMP" or "TEMPORARY" keyword occurs in between
+** CREATE and TABLE.
+**
+** The new table record is initialized and put in pParse->pNewTable.
+** As more of the CREATE TABLE statement is parsed, additional action
+** routines will be called to add more information to this record.
+** At the end of the CREATE TABLE statement, the sqlite3EndTable() routine
+** is called to complete the construction of the new table record.
+*/
+SQLITE_PRIVATE void sqlite3StartTable(
+  Parse *pParse,   /* Parser context */
+  Token *pName1,   /* First part of the name of the table or view */
+  Token *pName2,   /* Second part of the name of the table or view */
+  int isTemp,      /* True if this is a TEMP table */
+  int isView,      /* True if this is a VIEW */
+  int isVirtual,   /* True if this is a VIRTUAL table */
+  int noErr        /* Do nothing if table already exists */
+){
+  Table *pTable;
+  char *zName = 0; /* The name of the new table */
+  sqlite3 *db = pParse->db;
+  Vdbe *v;
+  int iDb;         /* Database number to create the table in */
+  Token *pName;    /* Unqualified name of the table to create */
+
+  /* The table or view name to create is passed to this routine via tokens
+  ** pName1 and pName2. If the table name was fully qualified, for example:
+  **
+  ** CREATE TABLE xxx.yyy (...);
+  ** 
+  ** Then pName1 is set to "xxx" and pName2 "yyy". On the other hand if
+  ** the table name is not fully qualified, i.e.:
+  **
+  ** CREATE TABLE yyy(...);
+  **
+  ** Then pName1 is set to "yyy" and pName2 is "".
+  **
+  ** The call below sets the pName pointer to point at the token (pName1 or
+  ** pName2) that stores the unqualified table name. The variable iDb is
+  ** set to the index of the database that the table or view is to be
+  ** created in.
+  */
+  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+  if( iDb<0 ) return;
+  if( !OMIT_TEMPDB && isTemp && iDb>1 ){
+    /* If creating a temp table, the name may not be qualified */
+    sqlite3ErrorMsg(pParse, "temporary table name must be unqualified");
+    return;
+  }
+  if( !OMIT_TEMPDB && isTemp ) iDb = 1;
+
+  pParse->sNameToken = *pName;
+  zName = sqlite3NameFromToken(db, pName);
+  if( zName==0 ) return;
+  if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
+    goto begin_table_error;
+  }
+  if( db->init.iDb==1 ) isTemp = 1;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  assert( (isTemp & 1)==isTemp );
+  {
+    int code;
+    char *zDb = db->aDb[iDb].zName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(isTemp), 0, zDb) ){
+      goto begin_table_error;
+    }
+    if( isView ){
+      if( !OMIT_TEMPDB && isTemp ){
+        code = SQLITE_CREATE_TEMP_VIEW;
+      }else{
+        code = SQLITE_CREATE_VIEW;
+      }
+    }else{
+      if( !OMIT_TEMPDB && isTemp ){
+        code = SQLITE_CREATE_TEMP_TABLE;
+      }else{
+        code = SQLITE_CREATE_TABLE;
+      }
+    }
+    if( !isVirtual && sqlite3AuthCheck(pParse, code, zName, 0, zDb) ){
+      goto begin_table_error;
+    }
+  }
+#endif
+
+  /* Make sure the new table name does not collide with an existing
+  ** index or table name in the same database.  Issue an error message if
+  ** it does. The exception is if the statement being parsed was passed
+  ** to an sqlite3_declare_vtab() call. In that case only the column names
+  ** and types will be used, so there is no need to test for namespace
+  ** collisions.
+  */
+  if( !IN_DECLARE_VTAB ){
+    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+      goto begin_table_error;
+    }
+    pTable = sqlite3FindTable(db, zName, db->aDb[iDb].zName);
+    if( pTable ){
+      if( !noErr ){
+        sqlite3ErrorMsg(pParse, "table %T already exists", pName);
+      }
+      goto begin_table_error;
+    }
+    if( sqlite3FindIndex(db, zName, 0)!=0 && (iDb==0 || !db->init.busy) ){
+      sqlite3ErrorMsg(pParse, "there is already an index named %s", zName);
+      goto begin_table_error;
+    }
+  }
+
+  pTable = sqlite3DbMallocZero(db, sizeof(Table));
+  if( pTable==0 ){
+    db->mallocFailed = 1;
+    pParse->rc = SQLITE_NOMEM;
+    pParse->nErr++;
+    goto begin_table_error;
+  }
+  pTable->zName = zName;
+  pTable->iPKey = -1;
+  pTable->pSchema = db->aDb[iDb].pSchema;
+  pTable->nRef = 1;
+  if( pParse->pNewTable ) sqlite3DeleteTable(pParse->pNewTable);
+  pParse->pNewTable = pTable;
+
+  /* If this is the magic sqlite_sequence table used by autoincrement,
+  ** then record a pointer to this table in the main database structure
+  ** so that INSERT can find the table easily.
+  */
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  if( !pParse->nested && strcmp(zName, "sqlite_sequence")==0 ){
+    pTable->pSchema->pSeqTab = pTable;
+  }
+#endif
+
+  /* Begin generating the code that will insert the table record into
+  ** the SQLITE_MASTER table.  Note in particular that we must go ahead
+  ** and allocate the record number for the table entry now.  Before any
+  ** PRIMARY KEY or UNIQUE keywords are parsed.  Those keywords will cause
+  ** indices to be created and the table record must come before the 
+  ** indices.  Hence, the record number for the table must be allocated
+  ** now.
+  */
+  if( !db->init.busy && (v = sqlite3GetVdbe(pParse))!=0 ){
+    int j1;
+    int fileFormat;
+    int reg1, reg2, reg3;
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( isVirtual ){
+      sqlite3VdbeAddOp0(v, OP_VBegin);
+    }
+#endif
+
+    /* If the file format and encoding in the database have not been set, 
+    ** set them now.
+    */
+    reg1 = pParse->regRowid = ++pParse->nMem;
+    reg2 = pParse->regRoot = ++pParse->nMem;
+    reg3 = ++pParse->nMem;
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, reg3, 1);   /* file_format */
+    sqlite3VdbeUsesBtree(v, iDb);
+    j1 = sqlite3VdbeAddOp1(v, OP_If, reg3);
+    fileFormat = (db->flags & SQLITE_LegacyFileFmt)!=0 ?
+                  1 : SQLITE_MAX_FILE_FORMAT;
+    sqlite3VdbeAddOp2(v, OP_Integer, fileFormat, reg3);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 1, reg3);
+    sqlite3VdbeAddOp2(v, OP_Integer, ENC(db), reg3);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 4, reg3);
+    sqlite3VdbeJumpHere(v, j1);
+
+    /* This just creates a place-holder record in the sqlite_master table.
+    ** The record created does not contain anything yet.  It will be replaced
+    ** by the real entry in code generated at sqlite3EndTable().
+    **
+    ** The rowid for the new entry is left on the top of the stack.
+    ** The rowid value is needed by the code that sqlite3EndTable will
+    ** generate.
+    */
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+    if( isView || isVirtual ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, reg2);
+    }else
+#endif
+    {
+      sqlite3VdbeAddOp2(v, OP_CreateTable, iDb, reg2);
+    }
+    sqlite3OpenMasterTable(pParse, iDb);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, 0, reg1);
+    sqlite3VdbeAddOp2(v, OP_Null, 0, reg3);
+    sqlite3VdbeAddOp3(v, OP_Insert, 0, reg3, reg1);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+    sqlite3VdbeAddOp0(v, OP_Close);
+  }
+
+  /* Normal (non-error) return. */
+  return;
+
+  /* If an error occurs, we jump here */
+begin_table_error:
+  sqlite3_free(zName);
+  return;
+}
+
+/*
+** This macro is used to compare two strings in a case-insensitive manner.
+** It is slightly faster than calling sqlite3StrICmp() directly, but
+** produces larger code.
+**
+** WARNING: This macro is not compatible with the strcmp() family. It
+** returns true if the two strings are equal, otherwise false.
+*/
+#define STRICMP(x, y) (\
+sqlite3UpperToLower[*(unsigned char *)(x)]==   \
+sqlite3UpperToLower[*(unsigned char *)(y)]     \
+&& sqlite3StrICmp((x)+1,(y)+1)==0 )
+
+/*
+** Add a new column to the table currently being constructed.
+**
+** The parser calls this routine once for each column declaration
+** in a CREATE TABLE statement.  sqlite3StartTable() gets called
+** first to get things going.  Then this routine is called for each
+** column.
+*/
+SQLITE_PRIVATE void sqlite3AddColumn(Parse *pParse, Token *pName){
+  Table *p;
+  int i;
+  char *z;
+  Column *pCol;
+  sqlite3 *db = pParse->db;
+  if( (p = pParse->pNewTable)==0 ) return;
+#if SQLITE_MAX_COLUMN
+  if( p->nCol+1>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns on %s", p->zName);
+    return;
+  }
+#endif
+  z = sqlite3NameFromToken(pParse->db, pName);
+  if( z==0 ) return;
+  for(i=0; i<p->nCol; i++){
+    if( STRICMP(z, p->aCol[i].zName) ){
+      sqlite3ErrorMsg(pParse, "duplicate column name: %s", z);
+      sqlite3_free(z);
+      return;
+    }
+  }
+  if( (p->nCol & 0x7)==0 ){
+    Column *aNew;
+    aNew = sqlite3DbRealloc(pParse->db,p->aCol,(p->nCol+8)*sizeof(p->aCol[0]));
+    if( aNew==0 ){
+      sqlite3_free(z);
+      return;
+    }
+    p->aCol = aNew;
+  }
+  pCol = &p->aCol[p->nCol];
+  memset(pCol, 0, sizeof(p->aCol[0]));
+  pCol->zName = z;
+ 
+  /* If there is no type specified, columns have the default affinity
+  ** 'NONE'. If there is a type specified, then sqlite3AddColumnType() will
+  ** be called next to set pCol->affinity correctly.
+  */
+  pCol->affinity = SQLITE_AFF_NONE;
+  p->nCol++;
+}
+
+/*
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
+** been seen on a column.  This routine sets the notNull flag on
+** the column currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse *pParse, int onError){
+  Table *p;
+  int i;
+  if( (p = pParse->pNewTable)==0 ) return;
+  i = p->nCol-1;
+  if( i>=0 ) p->aCol[i].notNull = onError;
+}
+
+/*
+** Scan the column type name zType (length nType) and return the
+** associated affinity type.
+**
+** This routine does a case-independent search of zType for the 
+** substrings in the following table. If one of the substrings is
+** found, the corresponding affinity is returned. If zType contains
+** more than one of the substrings, entries toward the top of 
+** the table take priority. For example, if zType is 'BLOBINT', 
+** SQLITE_AFF_INTEGER is returned.
+**
+** Substring     | Affinity
+** --------------------------------
+** 'INT'         | SQLITE_AFF_INTEGER
+** 'CHAR'        | SQLITE_AFF_TEXT
+** 'CLOB'        | SQLITE_AFF_TEXT
+** 'TEXT'        | SQLITE_AFF_TEXT
+** 'BLOB'        | SQLITE_AFF_NONE
+** 'REAL'        | SQLITE_AFF_REAL
+** 'FLOA'        | SQLITE_AFF_REAL
+** 'DOUB'        | SQLITE_AFF_REAL
+**
+** If none of the substrings in the above table are found,
+** SQLITE_AFF_NUMERIC is returned.
+*/
+SQLITE_PRIVATE char sqlite3AffinityType(const Token *pType){
+  u32 h = 0;
+  char aff = SQLITE_AFF_NUMERIC;
+  const unsigned char *zIn = pType->z;
+  const unsigned char *zEnd = &pType->z[pType->n];
+
+  while( zIn!=zEnd ){
+    h = (h<<8) + sqlite3UpperToLower[*zIn];
+    zIn++;
+    if( h==(('c'<<24)+('h'<<16)+('a'<<8)+'r') ){             /* CHAR */
+      aff = SQLITE_AFF_TEXT; 
+    }else if( h==(('c'<<24)+('l'<<16)+('o'<<8)+'b') ){       /* CLOB */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('t'<<24)+('e'<<16)+('x'<<8)+'t') ){       /* TEXT */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('b'<<24)+('l'<<16)+('o'<<8)+'b')          /* BLOB */
+        && (aff==SQLITE_AFF_NUMERIC || aff==SQLITE_AFF_REAL) ){
+      aff = SQLITE_AFF_NONE;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    }else if( h==(('r'<<24)+('e'<<16)+('a'<<8)+'l')          /* REAL */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('f'<<24)+('l'<<16)+('o'<<8)+'a')          /* FLOA */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('d'<<24)+('o'<<16)+('u'<<8)+'b')          /* DOUB */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+#endif
+    }else if( (h&0x00FFFFFF)==(('i'<<16)+('n'<<8)+'t') ){    /* INT */
+      aff = SQLITE_AFF_INTEGER;
+      break;
+    }
+  }
+
+  return aff;
+}
+
+/*
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.  The pFirst token is the first
+** token in the sequence of tokens that describe the type of the
+** column currently under construction.   pLast is the last token
+** in the sequence.  Use this information to construct a string
+** that contains the typename of the column and store that string
+** in zType.
+*/ 
+SQLITE_PRIVATE void sqlite3AddColumnType(Parse *pParse, Token *pType){
+  Table *p;
+  int i;
+  Column *pCol;
+
+  if( (p = pParse->pNewTable)==0 ) return;
+  i = p->nCol-1;
+  if( i<0 ) return;
+  pCol = &p->aCol[i];
+  sqlite3_free(pCol->zType);
+  pCol->zType = sqlite3NameFromToken(pParse->db, pType);
+  pCol->affinity = sqlite3AffinityType(pType);
+}
+
+/*
+** The expression is the default value for the most recently added column
+** of the table currently under construction.
+**
+** Default value expressions must be constant.  Raise an exception if this
+** is not the case.
+**
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse *pParse, Expr *pExpr){
+  Table *p;
+  Column *pCol;
+  if( (p = pParse->pNewTable)!=0 ){
+    pCol = &(p->aCol[p->nCol-1]);
+    if( !sqlite3ExprIsConstantOrFunction(pExpr) ){
+      sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
+          pCol->zName);
+    }else{
+      Expr *pCopy;
+      sqlite3 *db = pParse->db;
+      sqlite3ExprDelete(pCol->pDflt);
+      pCol->pDflt = pCopy = sqlite3ExprDup(db, pExpr);
+      if( pCopy ){
+        sqlite3TokenCopy(db, &pCopy->span, &pExpr->span);
+      }
+    }
+  }
+  sqlite3ExprDelete(pExpr);
+}
+
+/*
+** Designate the PRIMARY KEY for the table.  pList is a list of names 
+** of columns that form the primary key.  If pList is NULL, then the
+** most recently added column of the table is the primary key.
+**
+** A table can have at most one primary key.  If the table already has
+** a primary key (and this is the second primary key) then create an
+** error.
+**
+** If the PRIMARY KEY is on a single column whose datatype is INTEGER,
+** then we will try to use that column as the rowid.  Set the Table.iPKey
+** field of the table under construction to be the index of the
+** INTEGER PRIMARY KEY column.  Table.iPKey is set to -1 if there is
+** no INTEGER PRIMARY KEY.
+**
+** If the key is not an INTEGER PRIMARY KEY, then create a unique
+** index for the key.  No index is created for INTEGER PRIMARY KEYs.
+*/
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(
+  Parse *pParse,    /* Parsing context */
+  ExprList *pList,  /* List of field names to be indexed */
+  int onError,      /* What to do with a uniqueness conflict */
+  int autoInc,      /* True if the AUTOINCREMENT keyword is present */
+  int sortOrder     /* SQLITE_SO_ASC or SQLITE_SO_DESC */
+){
+  Table *pTab = pParse->pNewTable;
+  char *zType = 0;
+  int iCol = -1, i;
+  if( pTab==0 || IN_DECLARE_VTAB ) goto primary_key_exit;
+  if( pTab->hasPrimKey ){
+    sqlite3ErrorMsg(pParse, 
+      "table \"%s\" has more than one primary key", pTab->zName);
+    goto primary_key_exit;
+  }
+  pTab->hasPrimKey = 1;
+  if( pList==0 ){
+    iCol = pTab->nCol - 1;
+    pTab->aCol[iCol].isPrimKey = 1;
+  }else{
+    for(i=0; i<pList->nExpr; i++){
+      for(iCol=0; iCol<pTab->nCol; iCol++){
+        if( sqlite3StrICmp(pList->a[i].zName, pTab->aCol[iCol].zName)==0 ){
+          break;
+        }
+      }
+      if( iCol<pTab->nCol ){
+        pTab->aCol[iCol].isPrimKey = 1;
+      }
+    }
+    if( pList->nExpr>1 ) iCol = -1;
+  }
+  if( iCol>=0 && iCol<pTab->nCol ){
+    zType = pTab->aCol[iCol].zType;
+  }
+  if( zType && sqlite3StrICmp(zType, "INTEGER")==0
+        && sortOrder==SQLITE_SO_ASC ){
+    pTab->iPKey = iCol;
+    pTab->keyConf = onError;
+    pTab->autoInc = autoInc;
+  }else if( autoInc ){
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    sqlite3ErrorMsg(pParse, "AUTOINCREMENT is only allowed on an "
+       "INTEGER PRIMARY KEY");
+#endif
+  }else{
+    sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0, 0, sortOrder, 0);
+    pList = 0;
+  }
+
+primary_key_exit:
+  sqlite3ExprListDelete(pList);
+  return;
+}
+
+/*
+** Add a new CHECK constraint to the table currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(
+  Parse *pParse,    /* Parsing context */
+  Expr *pCheckExpr  /* The check expression */
+){
+#ifndef SQLITE_OMIT_CHECK
+  Table *pTab = pParse->pNewTable;
+  sqlite3 *db = pParse->db;
+  if( pTab && !IN_DECLARE_VTAB ){
+    /* The CHECK expression must be duplicated so that tokens refer
+    ** to malloced space and not the (ephemeral) text of the CREATE TABLE
+    ** statement */
+    pTab->pCheck = sqlite3ExprAnd(db, pTab->pCheck, 
+                                  sqlite3ExprDup(db, pCheckExpr));
+  }
+#endif
+  sqlite3ExprDelete(pCheckExpr);
+}
+
+/*
+** Set the collation function of the most recently parsed table column
+** to the CollSeq given.
+*/
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse *pParse, Token *pToken){
+  Table *p;
+  int i;
+  char *zColl;              /* Dequoted name of collation sequence */
+
+  if( (p = pParse->pNewTable)==0 ) return;
+  i = p->nCol-1;
+
+  zColl = sqlite3NameFromToken(pParse->db, pToken);
+  if( !zColl ) return;
+
+  if( sqlite3LocateCollSeq(pParse, zColl, -1) ){
+    Index *pIdx;
+    p->aCol[i].zColl = zColl;
+  
+    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
+    ** then an index may have been created on this column before the
+    ** collation type was added. Correct this if it is the case.
+    */
+    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->nColumn==1 );
+      if( pIdx->aiColumn[0]==i ){
+        pIdx->azColl[0] = p->aCol[i].zColl;
+      }
+    }
+  }else{
+    sqlite3_free(zColl);
+  }
+}
+
+/*
+** This function returns the collation sequence for database native text
+** encoding identified by the string zName, length nName.
+**
+** If the requested collation sequence is not available, or not available
+** in the database native encoding, the collation factory is invoked to
+** request it. If the collation factory does not supply such a sequence,
+** and the sequence is available in another text encoding, then that is
+** returned instead.
+**
+** If no versions of the requested collations sequence are available, or
+** another error occurs, NULL is returned and an error message written into
+** pParse.
+**
+** This routine is a wrapper around sqlite3FindCollSeq().  This routine
+** invokes the collation factory if the named collation cannot be found
+** and generates an error message.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName){
+  sqlite3 *db = pParse->db;
+  u8 enc = ENC(db);
+  u8 initbusy = db->init.busy;
+  CollSeq *pColl;
+
+  pColl = sqlite3FindCollSeq(db, enc, zName, nName, initbusy);
+  if( !initbusy && (!pColl || !pColl->xCmp) ){
+    pColl = sqlite3GetCollSeq(db, pColl, zName, nName);
+    if( !pColl ){
+      if( nName<0 ){
+        nName = strlen(zName);
+      }
+      sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", nName, zName);
+      pColl = 0;
+    }
+  }
+
+  return pColl;
+}
+
+
+/*
+** Generate code that will increment the schema cookie.
+**
+** The schema cookie is used to determine when the schema for the
+** database changes.  After each schema change, the cookie value
+** changes.  When a process first reads the schema it records the
+** cookie.  Thereafter, whenever it goes to access the database,
+** it checks the cookie to make sure the schema has not changed
+** since it was last read.
+**
+** This plan is not completely bullet-proof.  It is possible for
+** the schema to change multiple times and for the cookie to be
+** set back to prior value.  But schema changes are infrequent
+** and the probability of hitting the same cookie value is only
+** 1 chance in 2^32.  So we're safe enough.
+*/
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse *pParse, int iDb){
+  int r1 = sqlite3GetTempReg(pParse);
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3VdbeAddOp2(v, OP_Integer, db->aDb[iDb].pSchema->schema_cookie+1, r1);
+  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 0, r1);
+  sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Measure the number of characters needed to output the given
+** identifier.  The number returned includes any quotes used
+** but does not include the null terminator.
+**
+** The estimate is conservative.  It might be larger that what is
+** really needed.
+*/
+static int identLength(const char *z){
+  int n;
+  for(n=0; *z; n++, z++){
+    if( *z=='"' ){ n++; }
+  }
+  return n + 2;
+}
+
+/*
+** Write an identifier onto the end of the given string.  Add
+** quote characters as needed.
+*/
+static void identPut(char *z, int *pIdx, char *zSignedIdent){
+  unsigned char *zIdent = (unsigned char*)zSignedIdent;
+  int i, j, needQuote;
+  i = *pIdx;
+  for(j=0; zIdent[j]; j++){
+    if( !isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
+  }
+  needQuote =  zIdent[j]!=0 || isdigit(zIdent[0])
+                  || sqlite3KeywordCode(zIdent, j)!=TK_ID;
+  if( needQuote ) z[i++] = '"';
+  for(j=0; zIdent[j]; j++){
+    z[i++] = zIdent[j];
+    if( zIdent[j]=='"' ) z[i++] = '"';
+  }
+  if( needQuote ) z[i++] = '"';
+  z[i] = 0;
+  *pIdx = i;
+}
+
+/*
+** Generate a CREATE TABLE statement appropriate for the given
+** table.  Memory to hold the text of the statement is obtained
+** from sqliteMalloc() and must be freed by the calling function.
+*/
+static char *createTableStmt(sqlite3 *db, Table *p, int isTemp){
+  int i, k, n;
+  char *zStmt;
+  char *zSep, *zSep2, *zEnd, *z;
+  Column *pCol;
+  n = 0;
+  for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
+    n += identLength(pCol->zName);
+    z = pCol->zType;
+    if( z ){
+      n += (strlen(z) + 1);
+    }
+  }
+  n += identLength(p->zName);
+  if( n<50 ){
+    zSep = "";
+    zSep2 = ",";
+    zEnd = ")";
+  }else{
+    zSep = "\n  ";
+    zSep2 = ",\n  ";
+    zEnd = "\n)";
+  }
+  n += 35 + 6*p->nCol;
+  zStmt = sqlite3_malloc( n );
+  if( zStmt==0 ){
+    db->mallocFailed = 1;
+    return 0;
+  }
+  sqlite3_snprintf(n, zStmt,
+                  !OMIT_TEMPDB&&isTemp ? "CREATE TEMP TABLE ":"CREATE TABLE ");
+  k = strlen(zStmt);
+  identPut(zStmt, &k, p->zName);
+  zStmt[k++] = '(';
+  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
+    sqlite3_snprintf(n-k, &zStmt[k], zSep);
+    k += strlen(&zStmt[k]);
+    zSep = zSep2;
+    identPut(zStmt, &k, pCol->zName);
+    if( (z = pCol->zType)!=0 ){
+      zStmt[k++] = ' ';
+      assert( strlen(z)+k+1<=n );
+      sqlite3_snprintf(n-k, &zStmt[k], "%s", z);
+      k += strlen(z);
+    }
+  }
+  sqlite3_snprintf(n-k, &zStmt[k], "%s", zEnd);
+  return zStmt;
+}
+
+/*
+** This routine is called to report the final ")" that terminates
+** a CREATE TABLE statement.
+**
+** The table structure that other action routines have been building
+** is added to the internal hash tables, assuming no errors have
+** occurred.
+**
+** An entry for the table is made in the master table on disk, unless
+** this is a temporary table or db->init.busy==1.  When db->init.busy==1
+** it means we are reading the sqlite_master table because we just
+** connected to the database or because the sqlite_master table has
+** recently changed, so the entry for this table already exists in
+** the sqlite_master table.  We do not want to create it again.
+**
+** If the pSelect argument is not NULL, it means that this routine
+** was called to create a table generated from a 
+** "CREATE TABLE ... AS SELECT ..." statement.  The column names of
+** the new table will match the result set of the SELECT.
+*/
+SQLITE_PRIVATE void sqlite3EndTable(
+  Parse *pParse,          /* Parse context */
+  Token *pCons,           /* The ',' token after the last column defn. */
+  Token *pEnd,            /* The final ')' token in the CREATE TABLE */
+  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
+){
+  Table *p;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( (pEnd==0 && pSelect==0) || pParse->nErr || db->mallocFailed ) {
+    return;
+  }
+  p = pParse->pNewTable;
+  if( p==0 ) return;
+
+  assert( !db->init.busy || !pSelect );
+
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+
+#ifndef SQLITE_OMIT_CHECK
+  /* Resolve names in all CHECK constraint expressions.
+  */
+  if( p->pCheck ){
+    SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
+    NameContext sNC;                /* Name context for pParse->pNewTable */
+
+    memset(&sNC, 0, sizeof(sNC));
+    memset(&sSrc, 0, sizeof(sSrc));
+    sSrc.nSrc = 1;
+    sSrc.a[0].zName = p->zName;
+    sSrc.a[0].pTab = p;
+    sSrc.a[0].iCursor = -1;
+    sNC.pParse = pParse;
+    sNC.pSrcList = &sSrc;
+    sNC.isCheck = 1;
+    if( sqlite3ExprResolveNames(&sNC, p->pCheck) ){
+      return;
+    }
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+
+  /* If the db->init.busy is 1 it means we are reading the SQL off the
+  ** "sqlite_master" or "sqlite_temp_master" table on the disk.
+  ** So do not write to the disk again.  Extract the root page number
+  ** for the table from the db->init.newTnum field.  (The page number
+  ** should have been put there by the sqliteOpenCb routine.)
+  */
+  if( db->init.busy ){
+    p->tnum = db->init.newTnum;
+  }
+
+  /* If not initializing, then create a record for the new table
+  ** in the SQLITE_MASTER table of the database.  The record number
+  ** for the new table entry should already be on the stack.
+  **
+  ** If this is a TEMPORARY table, write the entry into the auxiliary
+  ** file instead of into the main database file.
+  */
+  if( !db->init.busy ){
+    int n;
+    Vdbe *v;
+    char *zType;    /* "view" or "table" */
+    char *zType2;   /* "VIEW" or "TABLE" */
+    char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */
+
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) return;
+
+    sqlite3VdbeAddOp1(v, OP_Close, 0);
+
+    /* Create the rootpage for the new table and push it onto the stack.
+    ** A view has no rootpage, so just push a zero onto the stack for
+    ** views.  Initialize zType at the same time.
+    */
+    if( p->pSelect==0 ){
+      /* A regular table */
+      zType = "table";
+      zType2 = "TABLE";
+#ifndef SQLITE_OMIT_VIEW
+    }else{
+      /* A view */
+      zType = "view";
+      zType2 = "VIEW";
+#endif
+    }
+
+    /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
+    ** statement to populate the new table. The root-page number for the
+    ** new table is on the top of the vdbe stack.
+    **
+    ** Once the SELECT has been coded by sqlite3Select(), it is in a
+    ** suitable state to query for the column names and types to be used
+    ** by the new table.
+    **
+    ** A shared-cache write-lock is not required to write to the new table,
+    ** as a schema-lock must have already been obtained to create it. Since
+    ** a schema-lock excludes all other database users, the write-lock would
+    ** be redundant.
+    */
+    if( pSelect ){
+      SelectDest dest;
+      Table *pSelTab;
+
+      sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
+      sqlite3VdbeChangeP5(v, 1);
+      pParse->nTab = 2;
+      sqlite3SelectDestInit(&dest, SRT_Table, 1);
+      sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);
+      sqlite3VdbeAddOp1(v, OP_Close, 1);
+      if( pParse->nErr==0 ){
+        pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSelect);
+        if( pSelTab==0 ) return;
+        assert( p->aCol==0 );
+        p->nCol = pSelTab->nCol;
+        p->aCol = pSelTab->aCol;
+        pSelTab->nCol = 0;
+        pSelTab->aCol = 0;
+        sqlite3DeleteTable(pSelTab);
+      }
+    }
+
+    /* Compute the complete text of the CREATE statement */
+    if( pSelect ){
+      zStmt = createTableStmt(db, p, p->pSchema==db->aDb[1].pSchema);
+    }else{
+      n = pEnd->z - pParse->sNameToken.z + 1;
+      zStmt = sqlite3MPrintf(db, 
+          "CREATE %s %.*s", zType2, n, pParse->sNameToken.z
+      );
+    }
+
+    /* A slot for the record has already been allocated in the 
+    ** SQLITE_MASTER table.  We just need to update that slot with all
+    ** the information we've collected.  The rowid for the preallocated
+    ** slot is the 2nd item on the stack.  The top of the stack is the
+    ** root page for the new table (or a 0 if this is a view).
+    */
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q.%s "
+         "SET type='%s', name=%Q, tbl_name=%Q, rootpage=#%d, sql=%Q "
+       "WHERE rowid=#%d",
+      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
+      zType,
+      p->zName,
+      p->zName,
+      pParse->regRoot,
+      zStmt,
+      pParse->regRowid
+    );
+    sqlite3_free(zStmt);
+    sqlite3ChangeCookie(pParse, iDb);
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    /* Check to see if we need to create an sqlite_sequence table for
+    ** keeping track of autoincrement keys.
+    */
+    if( p->autoInc ){
+      Db *pDb = &db->aDb[iDb];
+      if( pDb->pSchema->pSeqTab==0 ){
+        sqlite3NestedParse(pParse,
+          "CREATE TABLE %Q.sqlite_sequence(name,seq)",
+          pDb->zName
+        );
+      }
+    }
+#endif
+
+    /* Reparse everything to update our internal data structures */
+    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0,
+        sqlite3MPrintf(db, "tbl_name='%q'",p->zName), P4_DYNAMIC);
+  }
+
+
+  /* Add the table to the in-memory representation of the database.
+  */
+  if( db->init.busy && pParse->nErr==0 ){
+    Table *pOld;
+    FKey *pFKey; 
+    Schema *pSchema = p->pSchema;
+    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, strlen(p->zName)+1,p);
+    if( pOld ){
+      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
+      db->mallocFailed = 1;
+      return;
+    }
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
+      void *data;
+      int nTo = strlen(pFKey->zTo) + 1;
+      pFKey->pNextTo = sqlite3HashFind(&pSchema->aFKey, pFKey->zTo, nTo);
+      data = sqlite3HashInsert(&pSchema->aFKey, pFKey->zTo, nTo, pFKey);
+      if( data==(void *)pFKey ){
+        db->mallocFailed = 1;
+      }
+    }
+#endif
+    pParse->pNewTable = 0;
+    db->nTable++;
+    db->flags |= SQLITE_InternChanges;
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+    if( !p->pSelect ){
+      const char *zName = (const char *)pParse->sNameToken.z;
+      int nName;
+      assert( !pSelect && pCons && pEnd );
+      if( pCons->z==0 ){
+        pCons = pEnd;
+      }
+      nName = (const char *)pCons->z - zName;
+      p->addColOffset = 13 + sqlite3Utf8CharLen(zName, nName);
+    }
+#endif
+  }
+}
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** The parser calls this routine in order to create a new VIEW
+*/
+SQLITE_PRIVATE void sqlite3CreateView(
+  Parse *pParse,     /* The parsing context */
+  Token *pBegin,     /* The CREATE token that begins the statement */
+  Token *pName1,     /* The token that holds the name of the view */
+  Token *pName2,     /* The token that holds the name of the view */
+  Select *pSelect,   /* A SELECT statement that will become the new view */
+  int isTemp,        /* TRUE for a TEMPORARY view */
+  int noErr          /* Suppress error messages if VIEW already exists */
+){
+  Table *p;
+  int n;
+  const unsigned char *z;
+  Token sEnd;
+  DbFixer sFix;
+  Token *pName;
+  int iDb;
+  sqlite3 *db = pParse->db;
+
+  if( pParse->nVar>0 ){
+    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
+    sqlite3SelectDelete(pSelect);
+    return;
+  }
+  sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
+  p = pParse->pNewTable;
+  if( p==0 || pParse->nErr ){
+    sqlite3SelectDelete(pSelect);
+    return;
+  }
+  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+  if( sqlite3FixInit(&sFix, pParse, iDb, "view", pName)
+    && sqlite3FixSelect(&sFix, pSelect)
+  ){
+    sqlite3SelectDelete(pSelect);
+    return;
+  }
+
+  /* Make a copy of the entire SELECT statement that defines the view.
+  ** This will force all the Expr.token.z values to be dynamically
+  ** allocated rather than point to the input string - which means that
+  ** they will persist after the current sqlite3_exec() call returns.
+  */
+  p->pSelect = sqlite3SelectDup(db, pSelect);
+  sqlite3SelectDelete(pSelect);
+  if( db->mallocFailed ){
+    return;
+  }
+  if( !db->init.busy ){
+    sqlite3ViewGetColumnNames(pParse, p);
+  }
+
+  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
+  ** the end.
+  */
+  sEnd = pParse->sLastToken;
+  if( sEnd.z[0]!=0 && sEnd.z[0]!=';' ){
+    sEnd.z += sEnd.n;
+  }
+  sEnd.n = 0;
+  n = sEnd.z - pBegin->z;
+  z = (const unsigned char*)pBegin->z;
+  while( n>0 && (z[n-1]==';' || isspace(z[n-1])) ){ n--; }
+  sEnd.z = &z[n-1];
+  sEnd.n = 1;
+
+  /* Use sqlite3EndTable() to add the view to the SQLITE_MASTER table */
+  sqlite3EndTable(pParse, 0, &sEnd, 0);
+  return;
+}
+#endif /* SQLITE_OMIT_VIEW */
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+/*
+** The Table structure pTable is really a VIEW.  Fill in the names of
+** the columns of the view in the pTable structure.  Return the number
+** of errors.  If an error is seen leave an error message in pParse->zErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
+  Table *pSelTab;   /* A fake table from which we get the result set */
+  Select *pSel;     /* Copy of the SELECT that implements the view */
+  int nErr = 0;     /* Number of errors encountered */
+  int n;            /* Temporarily holds the number of cursors assigned */
+  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
+
+  assert( pTable );
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( sqlite3VtabCallConnect(pParse, pTable) ){
+    return SQLITE_ERROR;
+  }
+  if( IsVirtual(pTable) ) return 0;
+#endif
+
+#ifndef SQLITE_OMIT_VIEW
+  /* A positive nCol means the columns names for this view are
+  ** already known.
+  */
+  if( pTable->nCol>0 ) return 0;
+
+  /* A negative nCol is a special marker meaning that we are currently
+  ** trying to compute the column names.  If we enter this routine with
+  ** a negative nCol, it means two or more views form a loop, like this:
+  **
+  **     CREATE VIEW one AS SELECT * FROM two;
+  **     CREATE VIEW two AS SELECT * FROM one;
+  **
+  ** Actually, this error is caught previously and so the following test
+  ** should always fail.  But we will leave it in place just to be safe.
+  */
+  if( pTable->nCol<0 ){
+    sqlite3ErrorMsg(pParse, "view %s is circularly defined", pTable->zName);
+    return 1;
+  }
+  assert( pTable->nCol>=0 );
+
+  /* If we get this far, it means we need to compute the table names.
+  ** Note that the call to sqlite3ResultSetOfSelect() will expand any
+  ** "*" elements in the results set of the view and will assign cursors
+  ** to the elements of the FROM clause.  But we do not want these changes
+  ** to be permanent.  So the computation is done on a copy of the SELECT
+  ** statement that defines the view.
+  */
+  assert( pTable->pSelect );
+  pSel = sqlite3SelectDup(db, pTable->pSelect);
+  if( pSel ){
+    n = pParse->nTab;
+    sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
+    pTable->nCol = -1;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    xAuth = db->xAuth;
+    db->xAuth = 0;
+    pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSel);
+    db->xAuth = xAuth;
+#else
+    pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSel);
+#endif
+    pParse->nTab = n;
+    if( pSelTab ){
+      assert( pTable->aCol==0 );
+      pTable->nCol = pSelTab->nCol;
+      pTable->aCol = pSelTab->aCol;
+      pSelTab->nCol = 0;
+      pSelTab->aCol = 0;
+      sqlite3DeleteTable(pSelTab);
+      pTable->pSchema->flags |= DB_UnresetViews;
+    }else{
+      pTable->nCol = 0;
+      nErr++;
+    }
+    sqlite3SelectDelete(pSel);
+  } else {
+    nErr++;
+  }
+#endif /* SQLITE_OMIT_VIEW */
+  return nErr;  
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** Clear the column names from every VIEW in database idx.
+*/
+static void sqliteViewResetAll(sqlite3 *db, int idx){
+  HashElem *i;
+  if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
+  for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
+    Table *pTab = sqliteHashData(i);
+    if( pTab->pSelect ){
+      sqliteResetColumnNames(pTab);
+    }
+  }
+  DbClearProperty(db, idx, DB_UnresetViews);
+}
+#else
+# define sqliteViewResetAll(A,B)
+#endif /* SQLITE_OMIT_VIEW */
+
+/*
+** This function is called by the VDBE to adjust the internal schema
+** used by SQLite when the btree layer moves a table root page. The
+** root-page of a table or index in database iDb has changed from iFrom
+** to iTo.
+**
+** Ticket #1728:  The symbol table might still contain information
+** on tables and/or indices that are the process of being deleted.
+** If you are unlucky, one of those deleted indices or tables might
+** have the same rootpage number as the real table or index that is
+** being moved.  So we cannot stop searching after the first match 
+** because the first match might be for one of the deleted indices
+** or tables and not the table/index that is actually being moved.
+** We must continue looping until all tables and indices with
+** rootpage==iFrom have been converted to have a rootpage of iTo
+** in order to be certain that we got the right one.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+SQLITE_PRIVATE void sqlite3RootPageMoved(Db *pDb, int iFrom, int iTo){
+  HashElem *pElem;
+  Hash *pHash;
+
+  pHash = &pDb->pSchema->tblHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    if( pTab->tnum==iFrom ){
+      pTab->tnum = iTo;
+    }
+  }
+  pHash = &pDb->pSchema->idxHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Index *pIdx = sqliteHashData(pElem);
+    if( pIdx->tnum==iFrom ){
+      pIdx->tnum = iTo;
+    }
+  }
+}
+#endif
+
+/*
+** Write code to erase the table with root-page iTable from database iDb.
+** Also write code to modify the sqlite_master table and internal schema
+** if a root-page of another table is moved by the btree-layer whilst
+** erasing iTable (this can happen with an auto-vacuum database).
+*/ 
+static void destroyRootPage(Parse *pParse, int iTable, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int r1 = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp3(v, OP_Destroy, iTable, r1, iDb);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* OP_Destroy stores an in integer r1. If this integer
+  ** is non-zero, then it is the root page number of a table moved to
+  ** location iTable. The following code modifies the sqlite_master table to
+  ** reflect this.
+  **
+  ** The "#%d" in the SQL is a special constant that means whatever value
+  ** is on the top of the stack.  See sqlite3RegisterExpr().
+  */
+  sqlite3NestedParse(pParse, 
+     "UPDATE %Q.%s SET rootpage=%d WHERE #%d AND rootpage=#%d",
+     pParse->db->aDb[iDb].zName, SCHEMA_TABLE(iDb), iTable, r1, r1);
+#endif
+  sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Write VDBE code to erase table pTab and all associated indices on disk.
+** Code to update the sqlite_master tables and internal schema definitions
+** in case a root-page belonging to another table is moved by the btree layer
+** is also added (this can happen with an auto-vacuum database).
+*/
+static void destroyTable(Parse *pParse, Table *pTab){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  Index *pIdx;
+  int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  destroyRootPage(pParse, pTab->tnum, iDb);
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    destroyRootPage(pParse, pIdx->tnum, iDb);
+  }
+#else
+  /* If the database may be auto-vacuum capable (if SQLITE_OMIT_AUTOVACUUM
+  ** is not defined), then it is important to call OP_Destroy on the
+  ** table and index root-pages in order, starting with the numerically 
+  ** largest root-page number. This guarantees that none of the root-pages
+  ** to be destroyed is relocated by an earlier OP_Destroy. i.e. if the
+  ** following were coded:
+  **
+  ** OP_Destroy 4 0
+  ** ...
+  ** OP_Destroy 5 0
+  **
+  ** and root page 5 happened to be the largest root-page number in the
+  ** database, then root page 5 would be moved to page 4 by the 
+  ** "OP_Destroy 4 0" opcode. The subsequent "OP_Destroy 5 0" would hit
+  ** a free-list page.
+  */
+  int iTab = pTab->tnum;
+  int iDestroyed = 0;
+
+  while( 1 ){
+    Index *pIdx;
+    int iLargest = 0;
+
+    if( iDestroyed==0 || iTab<iDestroyed ){
+      iLargest = iTab;
+    }
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int iIdx = pIdx->tnum;
+      assert( pIdx->pSchema==pTab->pSchema );
+      if( (iDestroyed==0 || (iIdx<iDestroyed)) && iIdx>iLargest ){
+        iLargest = iIdx;
+      }
+    }
+    if( iLargest==0 ){
+      return;
+    }else{
+      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+      destroyRootPage(pParse, iLargest, iDb);
+      iDestroyed = iLargest;
+    }
+  }
+#endif
+}
+
+/*
+** This routine is called to do the work of a DROP TABLE statement.
+** pName is the name of the table to be dropped.
+*/
+SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
+  Table *pTab;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( pParse->nErr || db->mallocFailed ){
+    goto exit_drop_table;
+  }
+  assert( pName->nSrc==1 );
+  pTab = sqlite3LocateTable(pParse, isView, 
+                            pName->a[0].zName, pName->a[0].zDatabase);
+
+  if( pTab==0 ){
+    if( noErr ){
+      sqlite3ErrorClear(pParse);
+    }
+    goto exit_drop_table;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+
+  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
+  ** it is initialized.
+  */
+  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_drop_table;
+  }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    const char *zDb = db->aDb[iDb].zName;
+    const char *zArg2 = 0;
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb)){
+      goto exit_drop_table;
+    }
+    if( isView ){
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_VIEW;
+      }else{
+        code = SQLITE_DROP_VIEW;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    }else if( IsVirtual(pTab) ){
+      code = SQLITE_DROP_VTABLE;
+      zArg2 = pTab->pMod->zName;
+#endif
+    }else{
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_TABLE;
+      }else{
+        code = SQLITE_DROP_TABLE;
+      }
+    }
+    if( sqlite3AuthCheck(pParse, code, pTab->zName, zArg2, zDb) ){
+      goto exit_drop_table;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
+      goto exit_drop_table;
+    }
+  }
+#endif
+  if( pTab->readOnly || pTab==db->aDb[iDb].pSchema->pSeqTab ){
+    sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
+    goto exit_drop_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  /* Ensure DROP TABLE is not used on a view, and DROP VIEW is not used
+  ** on a table.
+  */
+  if( isView && pTab->pSelect==0 ){
+    sqlite3ErrorMsg(pParse, "use DROP TABLE to delete table %s", pTab->zName);
+    goto exit_drop_table;
+  }
+  if( !isView && pTab->pSelect ){
+    sqlite3ErrorMsg(pParse, "use DROP VIEW to delete view %s", pTab->zName);
+    goto exit_drop_table;
+  }
+#endif
+
+  /* Generate code to remove the table from the master table
+  ** on disk.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    Trigger *pTrigger;
+    Db *pDb = &db->aDb[iDb];
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      Vdbe *v = sqlite3GetVdbe(pParse);
+      if( v ){
+        sqlite3VdbeAddOp0(v, OP_VBegin);
+      }
+    }
+#endif
+
+    /* Drop all triggers associated with the table being dropped. Code
+    ** is generated to remove entries from sqlite_master and/or
+    ** sqlite_temp_master if required.
+    */
+    pTrigger = pTab->pTrigger;
+    while( pTrigger ){
+      assert( pTrigger->pSchema==pTab->pSchema || 
+          pTrigger->pSchema==db->aDb[1].pSchema );
+      sqlite3DropTriggerPtr(pParse, pTrigger);
+      pTrigger = pTrigger->pNext;
+    }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    /* Remove any entries of the sqlite_sequence table associated with
+    ** the table being dropped. This is done before the table is dropped
+    ** at the btree level, in case the sqlite_sequence table needs to
+    ** move as a result of the drop (can happen in auto-vacuum mode).
+    */
+    if( pTab->autoInc ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %s.sqlite_sequence WHERE name=%Q",
+        pDb->zName, pTab->zName
+      );
+    }
+#endif
+
+    /* Drop all SQLITE_MASTER table and index entries that refer to the
+    ** table. The program name loops through the master table and deletes
+    ** every row that refers to a table of the same name as the one being
+    ** dropped. Triggers are handled seperately because a trigger can be
+    ** created in the temp database that refers to a table in another
+    ** database.
+    */
+    sqlite3NestedParse(pParse, 
+        "DELETE FROM %Q.%s WHERE tbl_name=%Q and type!='trigger'",
+        pDb->zName, SCHEMA_TABLE(iDb), pTab->zName);
+
+    /* Drop any statistics from the sqlite_stat1 table, if it exists */
+    if( sqlite3FindTable(db, "sqlite_stat1", db->aDb[iDb].zName) ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q", pDb->zName, pTab->zName
+      );
+    }
+
+    if( !isView && !IsVirtual(pTab) ){
+      destroyTable(pParse, pTab);
+    }
+
+    /* Remove the table entry from SQLite's internal schema and modify
+    ** the schema cookie.
+    */
+    if( IsVirtual(pTab) ){
+      sqlite3VdbeAddOp4(v, OP_VDestroy, iDb, 0, 0, pTab->zName, 0);
+    }
+    sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
+    sqlite3ChangeCookie(pParse, iDb);
+  }
+  sqliteViewResetAll(db, iDb);
+
+exit_drop_table:
+  sqlite3SrcListDelete(pName);
+}
+
+/*
+** This routine is called to create a new foreign key on the table
+** currently under construction.  pFromCol determines which columns
+** in the current table point to the foreign key.  If pFromCol==0 then
+** connect the key to the last column inserted.  pTo is the name of
+** the table referred to.  pToCol is a list of tables in the other
+** pTo table that the foreign key points to.  flags contains all
+** information about the conflict resolution algorithms specified
+** in the ON DELETE, ON UPDATE and ON INSERT clauses.
+**
+** An FKey structure is created and added to the table currently
+** under construction in the pParse->pNewTable field.  The new FKey
+** is not linked into db->aFKey at this point - that does not happen
+** until sqlite3EndTable().
+**
+** The foreign key is set for IMMEDIATE processing.  A subsequent call
+** to sqlite3DeferForeignKey() might change this to DEFERRED.
+*/
+SQLITE_PRIVATE void sqlite3CreateForeignKey(
+  Parse *pParse,       /* Parsing context */
+  ExprList *pFromCol,  /* Columns in this table that point to other table */
+  Token *pTo,          /* Name of the other table */
+  ExprList *pToCol,    /* Columns in the other table */
+  int flags            /* Conflict resolution algorithms. */
+){
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  FKey *pFKey = 0;
+  Table *p = pParse->pNewTable;
+  int nByte;
+  int i;
+  int nCol;
+  char *z;
+
+  assert( pTo!=0 );
+  if( p==0 || pParse->nErr || IN_DECLARE_VTAB ) goto fk_end;
+  if( pFromCol==0 ){
+    int iCol = p->nCol-1;
+    if( iCol<0 ) goto fk_end;
+    if( pToCol && pToCol->nExpr!=1 ){
+      sqlite3ErrorMsg(pParse, "foreign key on %s"
+         " should reference only one column of table %T",
+         p->aCol[iCol].zName, pTo);
+      goto fk_end;
+    }
+    nCol = 1;
+  }else if( pToCol && pToCol->nExpr!=pFromCol->nExpr ){
+    sqlite3ErrorMsg(pParse,
+        "number of columns in foreign key does not match the number of "
+        "columns in the referenced table");
+    goto fk_end;
+  }else{
+    nCol = pFromCol->nExpr;
+  }
+  nByte = sizeof(*pFKey) + nCol*sizeof(pFKey->aCol[0]) + pTo->n + 1;
+  if( pToCol ){
+    for(i=0; i<pToCol->nExpr; i++){
+      nByte += strlen(pToCol->a[i].zName) + 1;
+    }
+  }
+  pFKey = sqlite3DbMallocZero(pParse->db, nByte );
+  if( pFKey==0 ){
+    goto fk_end;
+  }
+  pFKey->pFrom = p;
+  pFKey->pNextFrom = p->pFKey;
+  z = (char*)&pFKey[1];
+  pFKey->aCol = (struct sColMap*)z;
+  z += sizeof(struct sColMap)*nCol;
+  pFKey->zTo = z;
+  memcpy(z, pTo->z, pTo->n);
+  z[pTo->n] = 0;
+  z += pTo->n+1;
+  pFKey->pNextTo = 0;
+  pFKey->nCol = nCol;
+  if( pFromCol==0 ){
+    pFKey->aCol[0].iFrom = p->nCol-1;
+  }else{
+    for(i=0; i<nCol; i++){
+      int j;
+      for(j=0; j<p->nCol; j++){
+        if( sqlite3StrICmp(p->aCol[j].zName, pFromCol->a[i].zName)==0 ){
+          pFKey->aCol[i].iFrom = j;
+          break;
+        }
+      }
+      if( j>=p->nCol ){
+        sqlite3ErrorMsg(pParse, 
+          "unknown column \"%s\" in foreign key definition", 
+          pFromCol->a[i].zName);
+        goto fk_end;
+      }
+    }
+  }
+  if( pToCol ){
+    for(i=0; i<nCol; i++){
+      int n = strlen(pToCol->a[i].zName);
+      pFKey->aCol[i].zCol = z;
+      memcpy(z, pToCol->a[i].zName, n);
+      z[n] = 0;
+      z += n+1;
+    }
+  }
+  pFKey->isDeferred = 0;
+  pFKey->deleteConf = flags & 0xff;
+  pFKey->updateConf = (flags >> 8 ) & 0xff;
+  pFKey->insertConf = (flags >> 16 ) & 0xff;
+
+  /* Link the foreign key to the table as the last step.
+  */
+  p->pFKey = pFKey;
+  pFKey = 0;
+
+fk_end:
+  sqlite3_free(pFKey);
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+  sqlite3ExprListDelete(pFromCol);
+  sqlite3ExprListDelete(pToCol);
+}
+
+/*
+** This routine is called when an INITIALLY IMMEDIATE or INITIALLY DEFERRED
+** clause is seen as part of a foreign key definition.  The isDeferred
+** parameter is 1 for INITIALLY DEFERRED and 0 for INITIALLY IMMEDIATE.
+** The behavior of the most recently created foreign key is adjusted
+** accordingly.
+*/
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  Table *pTab;
+  FKey *pFKey;
+  if( (pTab = pParse->pNewTable)==0 || (pFKey = pTab->pFKey)==0 ) return;
+  pFKey->isDeferred = isDeferred;
+#endif
+}
+
+/*
+** Generate code that will erase and refill index *pIdx.  This is
+** used to initialize a newly created index or to recompute the
+** content of an index in response to a REINDEX command.
+**
+** if memRootPage is not negative, it means that the index is newly
+** created.  The register specified by memRootPage contains the
+** root page number of the index.  If memRootPage is negative, then
+** the index already exists and must be cleared before being refilled and
+** the root page number of the index is taken from pIndex->tnum.
+*/
+static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
+  Table *pTab = pIndex->pTable;  /* The table that is indexed */
+  int iTab = pParse->nTab;       /* Btree cursor used for pTab */
+  int iIdx = pParse->nTab+1;     /* Btree cursor used for pIndex */
+  int addr1;                     /* Address of top of loop */
+  int tnum;                      /* Root page of index */
+  Vdbe *v;                       /* Generate code into this virtual machine */
+  KeyInfo *pKey;                 /* KeyInfo for index */
+  int regIdxKey;                 /* Registers containing the index key */
+  int regRecord;                 /* Register holding assemblied index record */
+  sqlite3 *db = pParse->db;      /* The database connection */
+  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
+      db->aDb[iDb].zName ) ){
+    return;
+  }
+#endif
+
+  /* Require a write-lock on the table to perform this operation */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
+
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+  if( memRootPage>=0 ){
+    tnum = memRootPage;
+  }else{
+    tnum = pIndex->tnum;
+    sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
+  }
+  pKey = sqlite3IndexKeyinfo(pParse, pIndex);
+  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, tnum, iDb, 
+                    (char *)pKey, P4_KEYINFO_HANDOFF);
+  if( memRootPage>=0 ){
+    sqlite3VdbeChangeP5(v, 1);
+  }
+  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
+  regRecord = sqlite3GetTempReg(pParse);
+  regIdxKey = sqlite3GenerateIndexKey(pParse, pIndex, iTab, regRecord, 1);
+  if( pIndex->onError!=OE_None ){
+    int j1, j2;
+    int regRowid;
+
+    regRowid = regIdxKey + pIndex->nColumn;
+    j1 = sqlite3VdbeAddOp3(v, OP_IsNull, regIdxKey, 0, pIndex->nColumn);
+    j2 = sqlite3VdbeAddOp4(v, OP_IsUnique, iIdx,
+                           0, regRowid, (char*)regRecord, P4_INT32);
+    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, OE_Abort, 0,
+                    "indexed columns are not unique", P4_STATIC);
+    sqlite3VdbeJumpHere(v, j1);
+    sqlite3VdbeJumpHere(v, j2);
+  }
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1);
+  sqlite3VdbeJumpHere(v, addr1);
+  sqlite3VdbeAddOp1(v, OP_Close, iTab);
+  sqlite3VdbeAddOp1(v, OP_Close, iIdx);
+}
+
+/*
+** Create a new index for an SQL table.  pName1.pName2 is the name of the index 
+** and pTblList is the name of the table that is to be indexed.  Both will 
+** be NULL for a primary key or an index that is created to satisfy a
+** UNIQUE constraint.  If pTable and pIndex are NULL, use pParse->pNewTable
+** as the table to be indexed.  pParse->pNewTable is a table that is
+** currently being constructed by a CREATE TABLE statement.
+**
+** pList is a list of columns to be indexed.  pList will be NULL if this
+** is a primary key or unique-constraint on the most recent column added
+** to the table currently under construction.  
+*/
+SQLITE_PRIVATE void sqlite3CreateIndex(
+  Parse *pParse,     /* All information about this parse */
+  Token *pName1,     /* First part of index name. May be NULL */
+  Token *pName2,     /* Second part of index name. May be NULL */
+  SrcList *pTblName, /* Table to index. Use pParse->pNewTable if 0 */
+  ExprList *pList,   /* A list of columns to be indexed */
+  int onError,       /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  Token *pStart,     /* The CREATE token that begins this statement */
+  Token *pEnd,       /* The ")" that closes the CREATE INDEX statement */
+  int sortOrder,     /* Sort order of primary key when pList==NULL */
+  int ifNotExist     /* Omit error if index already exists */
+){
+  Table *pTab = 0;     /* Table to be indexed */
+  Index *pIndex = 0;   /* The index to be created */
+  char *zName = 0;     /* Name of the index */
+  int nName;           /* Number of characters in zName */
+  int i, j;
+  Token nullId;        /* Fake token for an empty ID list */
+  DbFixer sFix;        /* For assigning database names to pTable */
+  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
+  sqlite3 *db = pParse->db;
+  Db *pDb;             /* The specific table containing the indexed database */
+  int iDb;             /* Index of the database that is being written */
+  Token *pName = 0;    /* Unqualified name of the index to create */
+  struct ExprList_item *pListItem; /* For looping over pList */
+  int nCol;
+  int nExtra = 0;
+  char *zExtra;
+
+  if( pParse->nErr || db->mallocFailed || IN_DECLARE_VTAB ){
+    goto exit_create_index;
+  }
+
+  /*
+  ** Find the table that is to be indexed.  Return early if not found.
+  */
+  if( pTblName!=0 ){
+
+    /* Use the two-part index name to determine the database 
+    ** to search for the table. 'Fix' the table name to this db
+    ** before looking up the table.
+    */
+    assert( pName1 && pName2 );
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ) goto exit_create_index;
+
+#ifndef SQLITE_OMIT_TEMPDB
+    /* If the index name was unqualified, check if the the table
+    ** is a temp table. If so, set the database to 1. Do not do this
+    ** if initialising a database schema.
+    */
+    if( !db->init.busy ){
+      pTab = sqlite3SrcListLookup(pParse, pTblName);
+      if( pName2 && pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+        iDb = 1;
+      }
+    }
+#endif
+
+    if( sqlite3FixInit(&sFix, pParse, iDb, "index", pName) &&
+        sqlite3FixSrcList(&sFix, pTblName)
+    ){
+      /* Because the parser constructs pTblName from a single identifier,
+      ** sqlite3FixSrcList can never fail. */
+      assert(0);
+    }
+    pTab = sqlite3LocateTable(pParse, 0, pTblName->a[0].zName, 
+        pTblName->a[0].zDatabase);
+    if( !pTab ) goto exit_create_index;
+    assert( db->aDb[iDb].pSchema==pTab->pSchema );
+  }else{
+    assert( pName==0 );
+    pTab = pParse->pNewTable;
+    if( !pTab ) goto exit_create_index;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  }
+  pDb = &db->aDb[iDb];
+
+  if( pTab==0 || pParse->nErr ) goto exit_create_index;
+  if( pTab->readOnly ){
+    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
+    goto exit_create_index;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( pTab->pSelect ){
+    sqlite3ErrorMsg(pParse, "views may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+
+  /*
+  ** Find the name of the index.  Make sure there is not already another
+  ** index or table with the same name.  
+  **
+  ** Exception:  If we are reading the names of permanent indices from the
+  ** sqlite_master table (because some other process changed the schema) and
+  ** one of the index names collides with the name of a temporary table or
+  ** index, then we will continue to process this index.
+  **
+  ** If pName==0 it means that we are
+  ** dealing with a primary key or UNIQUE constraint.  We have to invent our
+  ** own name.
+  */
+  if( pName ){
+    zName = sqlite3NameFromToken(db, pName);
+    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto exit_create_index;
+    if( zName==0 ) goto exit_create_index;
+    if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
+      goto exit_create_index;
+    }
+    if( !db->init.busy ){
+      if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto exit_create_index;
+      if( sqlite3FindTable(db, zName, 0)!=0 ){
+        sqlite3ErrorMsg(pParse, "there is already a table named %s", zName);
+        goto exit_create_index;
+      }
+    }
+    if( sqlite3FindIndex(db, zName, pDb->zName)!=0 ){
+      if( !ifNotExist ){
+        sqlite3ErrorMsg(pParse, "index %s already exists", zName);
+      }
+      goto exit_create_index;
+    }
+  }else{
+    char zBuf[30];
+    int n;
+    Index *pLoop;
+    for(pLoop=pTab->pIndex, n=1; pLoop; pLoop=pLoop->pNext, n++){}
+    sqlite3_snprintf(sizeof(zBuf),zBuf,"_%d",n);
+    zName = 0;
+    sqlite3SetString(&zName, "sqlite_autoindex_", pTab->zName, zBuf, (char*)0);
+    if( zName==0 ){
+      db->mallocFailed = 1;
+      goto exit_create_index;
+    }
+  }
+
+  /* Check for authorization to create an index.
+  */
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    const char *zDb = pDb->zName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iDb), 0, zDb) ){
+      goto exit_create_index;
+    }
+    i = SQLITE_CREATE_INDEX;
+    if( !OMIT_TEMPDB && iDb==1 ) i = SQLITE_CREATE_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, i, zName, pTab->zName, zDb) ){
+      goto exit_create_index;
+    }
+  }
+#endif
+
+  /* If pList==0, it means this routine was called to make a primary
+  ** key out of the last column added to the table under construction.
+  ** So create a fake list to simulate this.
+  */
+  if( pList==0 ){
+    nullId.z = (u8*)pTab->aCol[pTab->nCol-1].zName;
+    nullId.n = strlen((char*)nullId.z);
+    pList = sqlite3ExprListAppend(pParse, 0, 0, &nullId);
+    if( pList==0 ) goto exit_create_index;
+    pList->a[0].sortOrder = sortOrder;
+  }
+
+  /* Figure out how many bytes of space are required to store explicitly
+  ** specified collation sequence names.
+  */
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr = pList->a[i].pExpr;
+    if( pExpr ){
+      nExtra += (1 + strlen(pExpr->pColl->zName));
+    }
+  }
+
+  /* 
+  ** Allocate the index structure. 
+  */
+  nName = strlen(zName);
+  nCol = pList->nExpr;
+  pIndex = sqlite3DbMallocZero(db, 
+      sizeof(Index) +              /* Index structure  */
+      sizeof(int)*nCol +           /* Index.aiColumn   */
+      sizeof(int)*(nCol+1) +       /* Index.aiRowEst   */
+      sizeof(char *)*nCol +        /* Index.azColl     */
+      sizeof(u8)*nCol +            /* Index.aSortOrder */
+      nName + 1 +                  /* Index.zName      */
+      nExtra                       /* Collation sequence names */
+  );
+  if( db->mallocFailed ){
+    goto exit_create_index;
+  }
+  pIndex->azColl = (char**)(&pIndex[1]);
+  pIndex->aiColumn = (int *)(&pIndex->azColl[nCol]);
+  pIndex->aiRowEst = (unsigned *)(&pIndex->aiColumn[nCol]);
+  pIndex->aSortOrder = (u8 *)(&pIndex->aiRowEst[nCol+1]);
+  pIndex->zName = (char *)(&pIndex->aSortOrder[nCol]);
+  zExtra = (char *)(&pIndex->zName[nName+1]);
+  memcpy(pIndex->zName, zName, nName+1);
+  pIndex->pTable = pTab;
+  pIndex->nColumn = pList->nExpr;
+  pIndex->onError = onError;
+  pIndex->autoIndex = pName==0;
+  pIndex->pSchema = db->aDb[iDb].pSchema;
+
+  /* Check to see if we should honor DESC requests on index columns
+  */
+  if( pDb->pSchema->file_format>=4 ){
+    sortOrderMask = -1;   /* Honor DESC */
+  }else{
+    sortOrderMask = 0;    /* Ignore DESC */
+  }
+
+  /* Scan the names of the columns of the table to be indexed and
+  ** load the column indices into the Index structure.  Report an error
+  ** if any column is not found.
+  */
+  for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
+    const char *zColName = pListItem->zName;
+    Column *pTabCol;
+    int requestedSortOrder;
+    char *zColl;                   /* Collation sequence name */
+
+    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
+      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
+    }
+    if( j>=pTab->nCol ){
+      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
+        pTab->zName, zColName);
+      goto exit_create_index;
+    }
+    /* TODO:  Add a test to make sure that the same column is not named
+    ** more than once within the same index.  Only the first instance of
+    ** the column will ever be used by the optimizer.  Note that using the
+    ** same column more than once cannot be an error because that would 
+    ** break backwards compatibility - it needs to be a warning.
+    */
+    pIndex->aiColumn[i] = j;
+    if( pListItem->pExpr ){
+      assert( pListItem->pExpr->pColl );
+      zColl = zExtra;
+      sqlite3_snprintf(nExtra, zExtra, "%s", pListItem->pExpr->pColl->zName);
+      zExtra += (strlen(zColl) + 1);
+    }else{
+      zColl = pTab->aCol[j].zColl;
+      if( !zColl ){
+        zColl = db->pDfltColl->zName;
+      }
+    }
+    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl, -1) ){
+      goto exit_create_index;
+    }
+    pIndex->azColl[i] = zColl;
+    requestedSortOrder = pListItem->sortOrder & sortOrderMask;
+    pIndex->aSortOrder[i] = requestedSortOrder;
+  }
+  sqlite3DefaultRowEst(pIndex);
+
+  if( pTab==pParse->pNewTable ){
+    /* This routine has been called to create an automatic index as a
+    ** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
+    ** a PRIMARY KEY or UNIQUE clause following the column definitions.
+    ** i.e. one of:
+    **
+    ** CREATE TABLE t(x PRIMARY KEY, y);
+    ** CREATE TABLE t(x, y, UNIQUE(x, y));
+    **
+    ** Either way, check to see if the table already has such an index. If
+    ** so, don't bother creating this one. This only applies to
+    ** automatically created indices. Users can do as they wish with
+    ** explicit indices.
+    */
+    Index *pIdx;
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int k;
+      assert( pIdx->onError!=OE_None );
+      assert( pIdx->autoIndex );
+      assert( pIndex->onError!=OE_None );
+
+      if( pIdx->nColumn!=pIndex->nColumn ) continue;
+      for(k=0; k<pIdx->nColumn; k++){
+        const char *z1 = pIdx->azColl[k];
+        const char *z2 = pIndex->azColl[k];
+        if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;
+        if( pIdx->aSortOrder[k]!=pIndex->aSortOrder[k] ) break;
+        if( z1!=z2 && sqlite3StrICmp(z1, z2) ) break;
+      }
+      if( k==pIdx->nColumn ){
+        if( pIdx->onError!=pIndex->onError ){
+          /* This constraint creates the same index as a previous
+          ** constraint specified somewhere in the CREATE TABLE statement.
+          ** However the ON CONFLICT clauses are different. If both this 
+          ** constraint and the previous equivalent constraint have explicit
+          ** ON CONFLICT clauses this is an error. Otherwise, use the
+          ** explicitly specified behaviour for the index.
+          */
+          if( !(pIdx->onError==OE_Default || pIndex->onError==OE_Default) ){
+            sqlite3ErrorMsg(pParse, 
+                "conflicting ON CONFLICT clauses specified", 0);
+          }
+          if( pIdx->onError==OE_Default ){
+            pIdx->onError = pIndex->onError;
+          }
+        }
+        goto exit_create_index;
+      }
+    }
+  }
+
+  /* Link the new Index structure to its table and to the other
+  ** in-memory database structures. 
+  */
+  if( db->init.busy ){
+    Index *p;
+    p = sqlite3HashInsert(&pIndex->pSchema->idxHash, 
+                         pIndex->zName, strlen(pIndex->zName)+1, pIndex);
+    if( p ){
+      assert( p==pIndex );  /* Malloc must have failed */
+      db->mallocFailed = 1;
+      goto exit_create_index;
+    }
+    db->flags |= SQLITE_InternChanges;
+    if( pTblName!=0 ){
+      pIndex->tnum = db->init.newTnum;
+    }
+  }
+
+  /* If the db->init.busy is 0 then create the index on disk.  This
+  ** involves writing the index into the master table and filling in the
+  ** index with the current table contents.
+  **
+  ** The db->init.busy is 0 when the user first enters a CREATE INDEX 
+  ** command.  db->init.busy is 1 when a database is opened and 
+  ** CREATE INDEX statements are read out of the master table.  In
+  ** the latter case the index already exists on disk, which is why
+  ** we don't want to recreate it.
+  **
+  ** If pTblName==0 it means this index is generated as a primary key
+  ** or UNIQUE constraint of a CREATE TABLE statement.  Since the table
+  ** has just been created, it contains no data and the index initialization
+  ** step can be skipped.
+  */
+  else if( db->init.busy==0 ){
+    Vdbe *v;
+    char *zStmt;
+    int iMem = ++pParse->nMem;
+
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) goto exit_create_index;
+
+
+    /* Create the rootpage for the index
+    */
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    sqlite3VdbeAddOp2(v, OP_CreateIndex, iDb, iMem);
+
+    /* Gather the complete text of the CREATE INDEX statement into
+    ** the zStmt variable
+    */
+    if( pStart && pEnd ){
+      /* A named index with an explicit CREATE INDEX statement */
+      zStmt = sqlite3MPrintf(db, "CREATE%s INDEX %.*s",
+        onError==OE_None ? "" : " UNIQUE",
+        pEnd->z - pName->z + 1,
+        pName->z);
+    }else{
+      /* An automatic index created by a PRIMARY KEY or UNIQUE constraint */
+      /* zStmt = sqlite3MPrintf(""); */
+      zStmt = 0;
+    }
+
+    /* Add an entry in sqlite_master for this index
+    */
+    sqlite3NestedParse(pParse, 
+        "INSERT INTO %Q.%s VALUES('index',%Q,%Q,#%d,%Q);",
+        db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
+        pIndex->zName,
+        pTab->zName,
+        iMem,
+        zStmt
+    );
+    sqlite3_free(zStmt);
+
+    /* Fill the index with data and reparse the schema. Code an OP_Expire
+    ** to invalidate all pre-compiled statements.
+    */
+    if( pTblName ){
+      sqlite3RefillIndex(pParse, pIndex, iMem);
+      sqlite3ChangeCookie(pParse, iDb);
+      sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0,
+         sqlite3MPrintf(db, "name='%q'", pIndex->zName), P4_DYNAMIC);
+      sqlite3VdbeAddOp1(v, OP_Expire, 0);
+    }
+  }
+
+  /* When adding an index to the list of indices for a table, make
+  ** sure all indices labeled OE_Replace come after all those labeled
+  ** OE_Ignore.  This is necessary for the correct operation of UPDATE
+  ** and INSERT.
+  */
+  if( db->init.busy || pTblName==0 ){
+    if( onError!=OE_Replace || pTab->pIndex==0
+         || pTab->pIndex->onError==OE_Replace){
+      pIndex->pNext = pTab->pIndex;
+      pTab->pIndex = pIndex;
+    }else{
+      Index *pOther = pTab->pIndex;
+      while( pOther->pNext && pOther->pNext->onError!=OE_Replace ){
+        pOther = pOther->pNext;
+      }
+      pIndex->pNext = pOther->pNext;
+      pOther->pNext = pIndex;
+    }
+    pIndex = 0;
+  }
+
+  /* Clean up before exiting */
+exit_create_index:
+  if( pIndex ){
+    freeIndex(pIndex);
+  }
+  sqlite3ExprListDelete(pList);
+  sqlite3SrcListDelete(pTblName);
+  sqlite3_free(zName);
+  return;
+}
+
+/*
+** Generate code to make sure the file format number is at least minFormat.
+** The generated code will increase the file format number if necessary.
+*/
+SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
+  Vdbe *v;
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    int r1 = sqlite3GetTempReg(pParse);
+    int r2 = sqlite3GetTempReg(pParse);
+    int j1;
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, 1);
+    sqlite3VdbeUsesBtree(v, iDb);
+    sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
+    j1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 1, r2);
+    sqlite3VdbeJumpHere(v, j1);
+    sqlite3ReleaseTempReg(pParse, r1);
+    sqlite3ReleaseTempReg(pParse, r2);
+  }
+}
+
+/*
+** Fill the Index.aiRowEst[] array with default information - information
+** to be used when we have not run the ANALYZE command.
+**
+** aiRowEst[0] is suppose to contain the number of elements in the index.
+** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the
+** number of rows in the table that match any particular value of the
+** first column of the index.  aiRowEst[2] is an estimate of the number
+** of rows that match any particular combiniation of the first 2 columns
+** of the index.  And so forth.  It must always be the case that
+*
+**           aiRowEst[N]<=aiRowEst[N-1]
+**           aiRowEst[N]>=1
+**
+** Apart from that, we have little to go on besides intuition as to
+** how aiRowEst[] should be initialized.  The numbers generated here
+** are based on typical values found in actual indices.
+*/
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index *pIdx){
+  unsigned *a = pIdx->aiRowEst;
+  int i;
+  assert( a!=0 );
+  a[0] = 1000000;
+  for(i=pIdx->nColumn; i>=5; i--){
+    a[i] = 5;
+  }
+  while( i>=1 ){
+    a[i] = 11 - i;
+    i--;
+  }
+  if( pIdx->onError!=OE_None ){
+    a[pIdx->nColumn] = 1;
+  }
+}
+
+/*
+** This routine will drop an existing named index.  This routine
+** implements the DROP INDEX statement.
+*/
+SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
+  Index *pIndex;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( pParse->nErr || db->mallocFailed ){
+    goto exit_drop_index;
+  }
+  assert( pName->nSrc==1 );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto exit_drop_index;
+  }
+  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);
+  if( pIndex==0 ){
+    if( !ifExists ){
+      sqlite3ErrorMsg(pParse, "no such index: %S", pName, 0);
+    }
+    pParse->checkSchema = 1;
+    goto exit_drop_index;
+  }
+  if( pIndex->autoIndex ){
+    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
+      "or PRIMARY KEY constraint cannot be dropped", 0);
+    goto exit_drop_index;
+  }
+  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code = SQLITE_DROP_INDEX;
+    Table *pTab = pIndex->pTable;
+    const char *zDb = db->aDb[iDb].zName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      goto exit_drop_index;
+    }
+    if( !OMIT_TEMPDB && iDb ) code = SQLITE_DROP_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, code, pIndex->zName, pTab->zName, zDb) ){
+      goto exit_drop_index;
+    }
+  }
+#endif
+
+  /* Generate code to remove the index and from the master table */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q.%s WHERE name=%Q",
+       db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
+       pIndex->zName
+    );
+    if( sqlite3FindTable(db, "sqlite_stat1", db->aDb[iDb].zName) ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %Q.sqlite_stat1 WHERE idx=%Q",
+        db->aDb[iDb].zName, pIndex->zName
+      );
+    }
+    sqlite3ChangeCookie(pParse, iDb);
+    destroyRootPage(pParse, pIndex->tnum, iDb);
+    sqlite3VdbeAddOp4(v, OP_DropIndex, iDb, 0, 0, pIndex->zName, 0);
+  }
+
+exit_drop_index:
+  sqlite3SrcListDelete(pName);
+}
+
+/*
+** pArray is a pointer to an array of objects.  Each object in the
+** array is szEntry bytes in size.  This routine allocates a new
+** object on the end of the array.
+**
+** *pnEntry is the number of entries already in use.  *pnAlloc is
+** the previously allocated size of the array.  initSize is the
+** suggested initial array size allocation.
+**
+** The index of the new entry is returned in *pIdx.
+**
+** This routine returns a pointer to the array of objects.  This
+** might be the same as the pArray parameter or it might be a different
+** pointer if the array was resized.
+*/
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(
+  sqlite3 *db,      /* Connection to notify of malloc failures */
+  void *pArray,     /* Array of objects.  Might be reallocated */
+  int szEntry,      /* Size of each object in the array */
+  int initSize,     /* Suggested initial allocation, in elements */
+  int *pnEntry,     /* Number of objects currently in use */
+  int *pnAlloc,     /* Current size of the allocation, in elements */
+  int *pIdx         /* Write the index of a new slot here */
+){
+  char *z;
+  if( *pnEntry >= *pnAlloc ){
+    void *pNew;
+    int newSize;
+    newSize = (*pnAlloc)*2 + initSize;
+    pNew = sqlite3DbRealloc(db, pArray, newSize*szEntry);
+    if( pNew==0 ){
+      *pIdx = -1;
+      return pArray;
+    }
+    *pnAlloc = newSize;
+    pArray = pNew;
+  }
+  z = (char*)pArray;
+  memset(&z[*pnEntry * szEntry], 0, szEntry);
+  *pIdx = *pnEntry;
+  ++*pnEntry;
+  return pArray;
+}
+
+/*
+** Append a new element to the given IdList.  Create a new IdList if
+** need be.
+**
+** A new IdList is returned, or NULL if malloc() fails.
+*/
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(sqlite3 *db, IdList *pList, Token *pToken){
+  int i;
+  if( pList==0 ){
+    pList = sqlite3DbMallocZero(db, sizeof(IdList) );
+    if( pList==0 ) return 0;
+    pList->nAlloc = 0;
+  }
+  pList->a = sqlite3ArrayAllocate(
+      db,
+      pList->a,
+      sizeof(pList->a[0]),
+      5,
+      &pList->nId,
+      &pList->nAlloc,
+      &i
+  );
+  if( i<0 ){
+    sqlite3IdListDelete(pList);
+    return 0;
+  }
+  pList->a[i].zName = sqlite3NameFromToken(db, pToken);
+  return pList;
+}
+
+/*
+** Delete an IdList.
+*/
+SQLITE_PRIVATE void sqlite3IdListDelete(IdList *pList){
+  int i;
+  if( pList==0 ) return;
+  for(i=0; i<pList->nId; i++){
+    sqlite3_free(pList->a[i].zName);
+  }
+  sqlite3_free(pList->a);
+  sqlite3_free(pList);
+}
+
+/*
+** Return the index in pList of the identifier named zId.  Return -1
+** if not found.
+*/
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList *pList, const char *zName){
+  int i;
+  if( pList==0 ) return -1;
+  for(i=0; i<pList->nId; i++){
+    if( sqlite3StrICmp(pList->a[i].zName, zName)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Append a new table name to the given SrcList.  Create a new SrcList if
+** need be.  A new entry is created in the SrcList even if pToken is NULL.
+**
+** A new SrcList is returned, or NULL if malloc() fails.
+**
+** If pDatabase is not null, it means that the table has an optional
+** database name prefix.  Like this:  "database.table".  The pDatabase
+** points to the table name and the pTable points to the database name.
+** The SrcList.a[].zName field is filled with the table name which might
+** come from pTable (if pDatabase is NULL) or from pDatabase.  
+** SrcList.a[].zDatabase is filled with the database name from pTable,
+** or with NULL if no database is specified.
+**
+** In other words, if call like this:
+**
+**         sqlite3SrcListAppend(D,A,B,0);
+**
+** Then B is a table name and the database name is unspecified.  If called
+** like this:
+**
+**         sqlite3SrcListAppend(D,A,B,C);
+**
+** Then C is the table name and B is the database name.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
+  sqlite3 *db,        /* Connection to notify of malloc failures */
+  SrcList *pList,     /* Append to this SrcList. NULL creates a new SrcList */
+  Token *pTable,      /* Table to append */
+  Token *pDatabase    /* Database of the table */
+){
+  struct SrcList_item *pItem;
+  if( pList==0 ){
+    pList = sqlite3DbMallocZero(db, sizeof(SrcList) );
+    if( pList==0 ) return 0;
+    pList->nAlloc = 1;
+  }
+  if( pList->nSrc>=pList->nAlloc ){
+    SrcList *pNew;
+    pList->nAlloc *= 2;
+    pNew = sqlite3DbRealloc(db, pList,
+               sizeof(*pList) + (pList->nAlloc-1)*sizeof(pList->a[0]) );
+    if( pNew==0 ){
+      sqlite3SrcListDelete(pList);
+      return 0;
+    }
+    pList = pNew;
+  }
+  pItem = &pList->a[pList->nSrc];
+  memset(pItem, 0, sizeof(pList->a[0]));
+  if( pDatabase && pDatabase->z==0 ){
+    pDatabase = 0;
+  }
+  if( pDatabase && pTable ){
+    Token *pTemp = pDatabase;
+    pDatabase = pTable;
+    pTable = pTemp;
+  }
+  pItem->zName = sqlite3NameFromToken(db, pTable);
+  pItem->zDatabase = sqlite3NameFromToken(db, pDatabase);
+  pItem->iCursor = -1;
+  pItem->isPopulated = 0;
+  pList->nSrc++;
+  return pList;
+}
+
+/*
+** Assign cursors to all tables in a SrcList
+*/
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
+  int i;
+  struct SrcList_item *pItem;
+  assert(pList || pParse->db->mallocFailed );
+  if( pList ){
+    for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+      if( pItem->iCursor>=0 ) break;
+      pItem->iCursor = pParse->nTab++;
+      if( pItem->pSelect ){
+        sqlite3SrcListAssignCursors(pParse, pItem->pSelect->pSrc);
+      }
+    }
+  }
+}
+
+/*
+** Delete an entire SrcList including all its substructure.
+*/
+SQLITE_PRIVATE void sqlite3SrcListDelete(SrcList *pList){
+  int i;
+  struct SrcList_item *pItem;
+  if( pList==0 ) return;
+  for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
+    sqlite3_free(pItem->zDatabase);
+    sqlite3_free(pItem->zName);
+    sqlite3_free(pItem->zAlias);
+    sqlite3DeleteTable(pItem->pTab);
+    sqlite3SelectDelete(pItem->pSelect);
+    sqlite3ExprDelete(pItem->pOn);
+    sqlite3IdListDelete(pItem->pUsing);
+  }
+  sqlite3_free(pList);
+}
+
+/*
+** This routine is called by the parser to add a new term to the
+** end of a growing FROM clause.  The "p" parameter is the part of
+** the FROM clause that has already been constructed.  "p" is NULL
+** if this is the first term of the FROM clause.  pTable and pDatabase
+** are the name of the table and database named in the FROM clause term.
+** pDatabase is NULL if the database name qualifier is missing - the
+** usual case.  If the term has a alias, then pAlias points to the
+** alias token.  If the term is a subquery, then pSubquery is the
+** SELECT statement that the subquery encodes.  The pTable and
+** pDatabase parameters are NULL for subqueries.  The pOn and pUsing
+** parameters are the content of the ON and USING clauses.
+**
+** Return a new SrcList which encodes is the FROM with the new
+** term added.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(
+  Parse *pParse,          /* Parsing context */
+  SrcList *p,             /* The left part of the FROM clause already seen */
+  Token *pTable,          /* Name of the table to add to the FROM clause */
+  Token *pDatabase,       /* Name of the database containing pTable */
+  Token *pAlias,          /* The right-hand side of the AS subexpression */
+  Select *pSubquery,      /* A subquery used in place of a table name */
+  Expr *pOn,              /* The ON clause of a join */
+  IdList *pUsing          /* The USING clause of a join */
+){
+  struct SrcList_item *pItem;
+  sqlite3 *db = pParse->db;
+  p = sqlite3SrcListAppend(db, p, pTable, pDatabase);
+  if( p==0 || p->nSrc==0 ){
+    sqlite3ExprDelete(pOn);
+    sqlite3IdListDelete(pUsing);
+    sqlite3SelectDelete(pSubquery);
+    return p;
+  }
+  pItem = &p->a[p->nSrc-1];
+  if( pAlias && pAlias->n ){
+    pItem->zAlias = sqlite3NameFromToken(db, pAlias);
+  }
+  pItem->pSelect = pSubquery;
+  pItem->pOn = pOn;
+  pItem->pUsing = pUsing;
+  return p;
+}
+
+/*
+** When building up a FROM clause in the parser, the join operator
+** is initially attached to the left operand.  But the code generator
+** expects the join operator to be on the right operand.  This routine
+** Shifts all join operators from left to right for an entire FROM
+** clause.
+**
+** Example: Suppose the join is like this:
+**
+**           A natural cross join B
+**
+** The operator is "natural cross join".  The A and B operands are stored
+** in p->a[0] and p->a[1], respectively.  The parser initially stores the
+** operator with A.  This routine shifts that operator over to B.
+*/
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(SrcList *p){
+  if( p && p->a ){
+    int i;
+    for(i=p->nSrc-1; i>0; i--){
+      p->a[i].jointype = p->a[i-1].jointype;
+    }
+    p->a[0].jointype = 0;
+  }
+}
+
+/*
+** Begin a transaction
+*/
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse *pParse, int type){
+  sqlite3 *db;
+  Vdbe *v;
+  int i;
+
+  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
+  if( pParse->nErr || db->mallocFailed ) return;
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ) return;
+
+  v = sqlite3GetVdbe(pParse);
+  if( !v ) return;
+  if( type!=TK_DEFERRED ){
+    for(i=0; i<db->nDb; i++){
+      sqlite3VdbeAddOp2(v, OP_Transaction, i, (type==TK_EXCLUSIVE)+1);
+      sqlite3VdbeUsesBtree(v, i);
+    }
+  }
+  sqlite3VdbeAddOp2(v, OP_AutoCommit, 0, 0);
+}
+
+/*
+** Commit a transaction
+*/
+SQLITE_PRIVATE void sqlite3CommitTransaction(Parse *pParse){
+  sqlite3 *db;
+  Vdbe *v;
+
+  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
+  if( pParse->nErr || db->mallocFailed ) return;
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ) return;
+
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, 0);
+  }
+}
+
+/*
+** Rollback a transaction
+*/
+SQLITE_PRIVATE void sqlite3RollbackTransaction(Parse *pParse){
+  sqlite3 *db;
+  Vdbe *v;
+
+  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
+  if( pParse->nErr || db->mallocFailed ) return;
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;
+
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, 1);
+  }
+}
+
+/*
+** Make sure the TEMP database is open and available for use.  Return
+** the number of errors.  Leave any error messages in the pParse structure.
+*/
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt==0 && !pParse->explain ){
+    int rc;
+    static const int flags = 
+          SQLITE_OPEN_READWRITE |
+          SQLITE_OPEN_CREATE |
+          SQLITE_OPEN_EXCLUSIVE |
+          SQLITE_OPEN_DELETEONCLOSE |
+          SQLITE_OPEN_TEMP_DB;
+
+    rc = sqlite3BtreeFactory(db, 0, 0, SQLITE_DEFAULT_CACHE_SIZE, flags,
+                                 &db->aDb[1].pBt);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
+        "file for storing temporary tables");
+      pParse->rc = rc;
+      return 1;
+    }
+    assert( (db->flags & SQLITE_InTrans)==0 || db->autoCommit );
+    assert( db->aDb[1].pSchema );
+    sqlite3PagerJournalMode(sqlite3BtreePager(db->aDb[1].pBt),
+                            db->dfltJournalMode);
+  }
+  return 0;
+}
+
+/*
+** Generate VDBE code that will verify the schema cookie and start
+** a read-transaction for all named database files.
+**
+** It is important that all schema cookies be verified and all
+** read transactions be started before anything else happens in
+** the VDBE program.  But this routine can be called after much other
+** code has been generated.  So here is what we do:
+**
+** The first time this routine is called, we code an OP_Goto that
+** will jump to a subroutine at the end of the program.  Then we
+** record every database that needs its schema verified in the
+** pParse->cookieMask field.  Later, after all other code has been
+** generated, the subroutine that does the cookie verifications and
+** starts the transactions will be coded and the OP_Goto P2 value
+** will be made to point to that subroutine.  The generation of the
+** cookie verification subroutine code happens in sqlite3FinishCoding().
+**
+** If iDb<0 then code the OP_Goto only - don't set flag to verify the
+** schema on any databases.  This can be used to position the OP_Goto
+** early in the code, before we know if any database tables will be used.
+*/
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
+  sqlite3 *db;
+  Vdbe *v;
+  int mask;
+
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;  /* This only happens if there was a prior error */
+  db = pParse->db;
+  if( pParse->cookieGoto==0 ){
+    pParse->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
+  }
+  if( iDb>=0 ){
+    assert( iDb<db->nDb );
+    assert( db->aDb[iDb].pBt!=0 || iDb==1 );
+    assert( iDb<SQLITE_MAX_ATTACHED+2 );
+    mask = 1<<iDb;
+    if( (pParse->cookieMask & mask)==0 ){
+      pParse->cookieMask |= mask;
+      pParse->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
+      if( !OMIT_TEMPDB && iDb==1 ){
+        sqlite3OpenTempDatabase(pParse);
+      }
+    }
+  }
+}
+
+/*
+** Generate VDBE code that prepares for doing an operation that
+** might change the database.
+**
+** This routine starts a new transaction if we are not already within
+** a transaction.  If we are already within a transaction, then a checkpoint
+** is set if the setStatement parameter is true.  A checkpoint should
+** be set for operations that might fail (due to a constraint) part of
+** the way through and which will need to undo some writes without having to
+** rollback the whole transaction.  For operations where all constraints
+** can be checked before any changes are made to the database, it is never
+** necessary to undo a write and the checkpoint should not be set.
+**
+** Only database iDb and the temp database are made writable by this call.
+** If iDb==0, then the main and temp databases are made writable.   If
+** iDb==1 then only the temp database is made writable.  If iDb>1 then the
+** specified auxiliary database and the temp database are made writable.
+*/
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+  sqlite3CodeVerifySchema(pParse, iDb);
+  pParse->writeMask |= 1<<iDb;
+  if( setStatement && pParse->nested==0 ){
+    sqlite3VdbeAddOp1(v, OP_Statement, iDb);
+  }
+  if( (OMIT_TEMPDB || iDb!=1) && pParse->db->aDb[1].pBt!=0 ){
+    sqlite3BeginWriteOperation(pParse, setStatement, 1);
+  }
+}
+
+/*
+** Check to see if pIndex uses the collating sequence pColl.  Return
+** true if it does and false if it does not.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static int collationMatch(const char *zColl, Index *pIndex){
+  int i;
+  for(i=0; i<pIndex->nColumn; i++){
+    const char *z = pIndex->azColl[i];
+    if( z==zColl || (z && zColl && 0==sqlite3StrICmp(z, zColl)) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif
+
+/*
+** Recompute all indices of pTab that use the collating sequence pColl.
+** If pColl==0 then recompute all indices of pTab.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexTable(Parse *pParse, Table *pTab, char const *zColl){
+  Index *pIndex;              /* An index associated with pTab */
+
+  for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+    if( zColl==0 || collationMatch(zColl, pIndex) ){
+      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+      sqlite3BeginWriteOperation(pParse, 0, iDb);
+      sqlite3RefillIndex(pParse, pIndex, -1);
+    }
+  }
+}
+#endif
+
+/*
+** Recompute all indices of all tables in all databases where the
+** indices use the collating sequence pColl.  If pColl==0 then recompute
+** all indices everywhere.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexDatabases(Parse *pParse, char const *zColl){
+  Db *pDb;                    /* A single database */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  HashElem *k;                /* For looping over tables in pDb */
+  Table *pTab;                /* A table in the database */
+
+  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
+    assert( pDb!=0 );
+    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
+      pTab = (Table*)sqliteHashData(k);
+      reindexTable(pParse, pTab, zColl);
+    }
+  }
+}
+#endif
+
+/*
+** Generate code for the REINDEX command.
+**
+**        REINDEX                            -- 1
+**        REINDEX  <collation>               -- 2
+**        REINDEX  ?<database>.?<tablename>  -- 3
+**        REINDEX  ?<database>.?<indexname>  -- 4
+**
+** Form 1 causes all indices in all attached databases to be rebuilt.
+** Form 2 rebuilds all indices in all databases that use the named
+** collating function.  Forms 3 and 4 rebuild the named index or all
+** indices associated with the named table.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+SQLITE_PRIVATE void sqlite3Reindex(Parse *pParse, Token *pName1, Token *pName2){
+  CollSeq *pColl;             /* Collating sequence to be reindexed, or NULL */
+  char *z;                    /* Name of a table or index */
+  const char *zDb;            /* Name of the database */
+  Table *pTab;                /* A table in the database */
+  Index *pIndex;              /* An index associated with pTab */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  Token *pObjName;            /* Name of the table or index to be reindexed */
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  if( pName1==0 || pName1->z==0 ){
+    reindexDatabases(pParse, 0);
+    return;
+  }else if( pName2==0 || pName2->z==0 ){
+    char *zColl;
+    assert( pName1->z );
+    zColl = sqlite3NameFromToken(pParse->db, pName1);
+    if( !zColl ) return;
+    pColl = sqlite3FindCollSeq(db, ENC(db), zColl, -1, 0);
+    if( pColl ){
+      if( zColl ){
+        reindexDatabases(pParse, zColl);
+        sqlite3_free(zColl);
+      }
+      return;
+    }
+    sqlite3_free(zColl);
+  }
+  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pObjName);
+  if( iDb<0 ) return;
+  z = sqlite3NameFromToken(db, pObjName);
+  if( z==0 ) return;
+  zDb = db->aDb[iDb].zName;
+  pTab = sqlite3FindTable(db, z, zDb);
+  if( pTab ){
+    reindexTable(pParse, pTab, 0);
+    sqlite3_free(z);
+    return;
+  }
+  pIndex = sqlite3FindIndex(db, z, zDb);
+  sqlite3_free(z);
+  if( pIndex ){
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3RefillIndex(pParse, pIndex, -1);
+    return;
+  }
+  sqlite3ErrorMsg(pParse, "unable to identify the object to be reindexed");
+}
+#endif
+
+/*
+** Return a dynamicly allocated KeyInfo structure that can be used
+** with OP_OpenRead or OP_OpenWrite to access database index pIdx.
+**
+** If successful, a pointer to the new structure is returned. In this case
+** the caller is responsible for calling sqlite3_free() on the returned 
+** pointer. If an error occurs (out of memory or missing collation 
+** sequence), NULL is returned and the state of pParse updated to reflect
+** the error.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3IndexKeyinfo(Parse *pParse, Index *pIdx){
+  int i;
+  int nCol = pIdx->nColumn;
+  int nBytes = sizeof(KeyInfo) + (nCol-1)*sizeof(CollSeq*) + nCol;
+  KeyInfo *pKey = (KeyInfo *)sqlite3DbMallocZero(pParse->db, nBytes);
+
+  if( pKey ){
+    pKey->db = pParse->db;
+    pKey->aSortOrder = (u8 *)&(pKey->aColl[nCol]);
+    assert( &pKey->aSortOrder[nCol]==&(((u8 *)pKey)[nBytes]) );
+    for(i=0; i<nCol; i++){
+      char *zColl = pIdx->azColl[i];
+      assert( zColl );
+      pKey->aColl[i] = sqlite3LocateCollSeq(pParse, zColl, -1);
+      pKey->aSortOrder[i] = pIdx->aSortOrder[i];
+    }
+    pKey->nField = nCol;
+  }
+
+  if( pParse->nErr ){
+    sqlite3_free(pKey);
+    pKey = 0;
+  }
+  return pKey;
+}
+
+/************** End of build.c ***********************************************/
+/************** Begin file callback.c ****************************************/
+/*
+** 2005 May 23 
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains functions used to access the internal hash tables
+** of user defined functions and collation sequences.
+**
+** $Id: callback.c,v 1.23 2007/08/29 12:31:26 danielk1977 Exp $
+*/
+
+
+/*
+** Invoke the 'collation needed' callback to request a collation sequence
+** in the database text encoding of name zName, length nName.
+** If the collation sequence
+*/
+static void callCollNeeded(sqlite3 *db, const char *zName, int nName){
+  assert( !db->xCollNeeded || !db->xCollNeeded16 );
+  if( nName<0 ) nName = strlen(zName);
+  if( db->xCollNeeded ){
+    char *zExternal = sqlite3DbStrNDup(db, zName, nName);
+    if( !zExternal ) return;
+    db->xCollNeeded(db->pCollNeededArg, db, (int)ENC(db), zExternal);
+    sqlite3_free(zExternal);
+  }
+#ifndef SQLITE_OMIT_UTF16
+  if( db->xCollNeeded16 ){
+    char const *zExternal;
+    sqlite3_value *pTmp = sqlite3ValueNew(db);
+    sqlite3ValueSetStr(pTmp, nName, zName, SQLITE_UTF8, SQLITE_STATIC);
+    zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
+    if( zExternal ){
+      db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal);
+    }
+    sqlite3ValueFree(pTmp);
+  }
+#endif
+}
+
+/*
+** This routine is called if the collation factory fails to deliver a
+** collation function in the best encoding but there may be other versions
+** of this collation function (for other text encodings) available. Use one
+** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
+** possible.
+*/
+static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
+  CollSeq *pColl2;
+  char *z = pColl->zName;
+  int n = strlen(z);
+  int i;
+  static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
+  for(i=0; i<3; i++){
+    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, n, 0);
+    if( pColl2->xCmp!=0 ){
+      memcpy(pColl, pColl2, sizeof(CollSeq));
+      pColl->xDel = 0;         /* Do not copy the destructor */
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** This function is responsible for invoking the collation factory callback
+** or substituting a collation sequence of a different encoding when the
+** requested collation sequence is not available in the database native
+** encoding.
+** 
+** If it is not NULL, then pColl must point to the database native encoding 
+** collation sequence with name zName, length nName.
+**
+** The return value is either the collation sequence to be used in database
+** db for collation type name zName, length nName, or NULL, if no collation
+** sequence can be found.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(
+  sqlite3* db, 
+  CollSeq *pColl, 
+  const char *zName, 
+  int nName
+){
+  CollSeq *p;
+
+  p = pColl;
+  if( !p ){
+    p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0);
+  }
+  if( !p || !p->xCmp ){
+    /* No collation sequence of this type for this encoding is registered.
+    ** Call the collation factory to see if it can supply us with one.
+    */
+    callCollNeeded(db, zName, nName);
+    p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0);
+  }
+  if( p && !p->xCmp && synthCollSeq(db, p) ){
+    p = 0;
+  }
+  assert( !p || p->xCmp );
+  return p;
+}
+
+/*
+** This routine is called on a collation sequence before it is used to
+** check that it is defined. An undefined collation sequence exists when
+** a database is loaded that contains references to collation sequences
+** that have not been defined by sqlite3_create_collation() etc.
+**
+** If required, this routine calls the 'collation needed' callback to
+** request a definition of the collating sequence. If this doesn't work, 
+** an equivalent collating sequence that uses a text encoding different
+** from the main database is substituted, if one is available.
+*/
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
+  if( pColl ){
+    const char *zName = pColl->zName;
+    CollSeq *p = sqlite3GetCollSeq(pParse->db, pColl, zName, -1);
+    if( !p ){
+      if( pParse->nErr==0 ){
+        sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+      }
+      pParse->nErr++;
+      return SQLITE_ERROR;
+    }
+    assert( p==pColl );
+  }
+  return SQLITE_OK;
+}
+
+
+
+/*
+** Locate and return an entry from the db.aCollSeq hash table. If the entry
+** specified by zName and nName is not found and parameter 'create' is
+** true, then create a new entry. Otherwise return NULL.
+**
+** Each pointer stored in the sqlite3.aCollSeq hash table contains an
+** array of three CollSeq structures. The first is the collation sequence
+** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
+**
+** Stored immediately after the three collation sequences is a copy of
+** the collation sequence name. A pointer to this string is stored in
+** each collation sequence structure.
+*/
+static CollSeq *findCollSeqEntry(
+  sqlite3 *db,
+  const char *zName,
+  int nName,
+  int create
+){
+  CollSeq *pColl;
+  if( nName<0 ) nName = strlen(zName);
+  pColl = sqlite3HashFind(&db->aCollSeq, zName, nName);
+
+  if( 0==pColl && create ){
+    pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName + 1 );
+    if( pColl ){
+      CollSeq *pDel = 0;
+      pColl[0].zName = (char*)&pColl[3];
+      pColl[0].enc = SQLITE_UTF8;
+      pColl[1].zName = (char*)&pColl[3];
+      pColl[1].enc = SQLITE_UTF16LE;
+      pColl[2].zName = (char*)&pColl[3];
+      pColl[2].enc = SQLITE_UTF16BE;
+      memcpy(pColl[0].zName, zName, nName);
+      pColl[0].zName[nName] = 0;
+      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);
+
+      /* If a malloc() failure occured in sqlite3HashInsert(), it will 
+      ** return the pColl pointer to be deleted (because it wasn't added
+      ** to the hash table).
+      */
+      assert( pDel==0 || pDel==pColl );
+      if( pDel!=0 ){
+        db->mallocFailed = 1;
+        sqlite3_free(pDel);
+        pColl = 0;
+      }
+    }
+  }
+  return pColl;
+}
+
+/*
+** Parameter zName points to a UTF-8 encoded string nName bytes long.
+** Return the CollSeq* pointer for the collation sequence named zName
+** for the encoding 'enc' from the database 'db'.
+**
+** If the entry specified is not found and 'create' is true, then create a
+** new entry.  Otherwise return NULL.
+**
+** A separate function sqlite3LocateCollSeq() is a wrapper around
+** this routine.  sqlite3LocateCollSeq() invokes the collation factory
+** if necessary and generates an error message if the collating sequence
+** cannot be found.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(
+  sqlite3 *db,
+  u8 enc,
+  const char *zName,
+  int nName,
+  int create
+){
+  CollSeq *pColl;
+  if( zName ){
+    pColl = findCollSeqEntry(db, zName, nName, create);
+  }else{
+    pColl = db->pDfltColl;
+  }
+  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
+  if( pColl ) pColl += enc-1;
+  return pColl;
+}
+
+/*
+** Locate a user function given a name, a number of arguments and a flag
+** indicating whether the function prefers UTF-16 over UTF-8.  Return a
+** pointer to the FuncDef structure that defines that function, or return
+** NULL if the function does not exist.
+**
+** If the createFlag argument is true, then a new (blank) FuncDef
+** structure is created and liked into the "db" structure if a
+** no matching function previously existed.  When createFlag is true
+** and the nArg parameter is -1, then only a function that accepts
+** any number of arguments will be returned.
+**
+** If createFlag is false and nArg is -1, then the first valid
+** function found is returned.  A function is valid if either xFunc
+** or xStep is non-zero.
+**
+** If createFlag is false, then a function with the required name and
+** number of arguments may be returned even if the eTextRep flag does not
+** match that requested.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
+  sqlite3 *db,       /* An open database */
+  const char *zName, /* Name of the function.  Not null-terminated */
+  int nName,         /* Number of characters in the name */
+  int nArg,          /* Number of arguments.  -1 means any number */
+  u8 enc,            /* Preferred text encoding */
+  int createFlag     /* Create new entry if true and does not otherwise exist */
+){
+  FuncDef *p;         /* Iterator variable */
+  FuncDef *pFirst;    /* First function with this name */
+  FuncDef *pBest = 0; /* Best match found so far */
+  int bestmatch = 0;  
+
+
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  if( nArg<-1 ) nArg = -1;
+
+  pFirst = (FuncDef*)sqlite3HashFind(&db->aFunc, zName, nName);
+  for(p=pFirst; p; p=p->pNext){
+    /* During the search for the best function definition, bestmatch is set
+    ** as follows to indicate the quality of the match with the definition
+    ** pointed to by pBest:
+    **
+    ** 0: pBest is NULL. No match has been found.
+    ** 1: A variable arguments function that prefers UTF-8 when a UTF-16
+    **    encoding is requested, or vice versa.
+    ** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
+    **    requested, or vice versa.
+    ** 3: A variable arguments function using the same text encoding.
+    ** 4: A function with the exact number of arguments requested that
+    **    prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
+    ** 5: A function with the exact number of arguments requested that
+    **    prefers UTF-16LE when UTF-16BE is requested, or vice versa.
+    ** 6: An exact match.
+    **
+    ** A larger value of 'matchqual' indicates a more desirable match.
+    */
+    if( p->nArg==-1 || p->nArg==nArg || nArg==-1 ){
+      int match = 1;          /* Quality of this match */
+      if( p->nArg==nArg || nArg==-1 ){
+        match = 4;
+      }
+      if( enc==p->iPrefEnc ){
+        match += 2;
+      }
+      else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) ||
+               (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){
+        match += 1;
+      }
+
+      if( match>bestmatch ){
+        pBest = p;
+        bestmatch = match;
+      }
+    }
+  }
+
+  /* If the createFlag parameter is true, and the seach did not reveal an
+  ** exact match for the name, number of arguments and encoding, then add a
+  ** new entry to the hash table and return it.
+  */
+  if( createFlag && bestmatch<6 && 
+      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName))!=0 ){
+    pBest->nArg = nArg;
+    pBest->pNext = pFirst;
+    pBest->iPrefEnc = enc;
+    memcpy(pBest->zName, zName, nName);
+    pBest->zName[nName] = 0;
+    if( pBest==sqlite3HashInsert(&db->aFunc,pBest->zName,nName,(void*)pBest) ){
+      db->mallocFailed = 1;
+      sqlite3_free(pBest);
+      return 0;
+    }
+  }
+
+  if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){
+    return pBest;
+  }
+  return 0;
+}
+
+/*
+** Free all resources held by the schema structure. The void* argument points
+** at a Schema struct. This function does not call sqlite3_free() on the 
+** pointer itself, it just cleans up subsiduary resources (i.e. the contents
+** of the schema hash tables).
+*/
+SQLITE_PRIVATE void sqlite3SchemaFree(void *p){
+  Hash temp1;
+  Hash temp2;
+  HashElem *pElem;
+  Schema *pSchema = (Schema *)p;
+
+  temp1 = pSchema->tblHash;
+  temp2 = pSchema->trigHash;
+  sqlite3HashInit(&pSchema->trigHash, SQLITE_HASH_STRING, 0);
+  sqlite3HashClear(&pSchema->aFKey);
+  sqlite3HashClear(&pSchema->idxHash);
+  for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
+    sqlite3DeleteTrigger((Trigger*)sqliteHashData(pElem));
+  }
+  sqlite3HashClear(&temp2);
+  sqlite3HashInit(&pSchema->tblHash, SQLITE_HASH_STRING, 0);
+  for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    sqlite3DeleteTable(pTab);
+  }
+  sqlite3HashClear(&temp1);
+  pSchema->pSeqTab = 0;
+  pSchema->flags &= ~DB_SchemaLoaded;
+}
+
+/*
+** Find and return the schema associated with a BTree.  Create
+** a new one if necessary.
+*/
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
+  Schema * p;
+  if( pBt ){
+    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaFree);
+  }else{
+    p = (Schema *)sqlite3MallocZero(sizeof(Schema));
+  }
+  if( !p ){
+    db->mallocFailed = 1;
+  }else if ( 0==p->file_format ){
+    sqlite3HashInit(&p->tblHash, SQLITE_HASH_STRING, 0);
+    sqlite3HashInit(&p->idxHash, SQLITE_HASH_STRING, 0);
+    sqlite3HashInit(&p->trigHash, SQLITE_HASH_STRING, 0);
+    sqlite3HashInit(&p->aFKey, SQLITE_HASH_STRING, 1);
+    p->enc = SQLITE_UTF8;
+  }
+  return p;
+}
+
+/************** End of callback.c ********************************************/
+/************** Begin file delete.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** in order to generate code for DELETE FROM statements.
+**
+** $Id: delete.c,v 1.169 2008/04/28 18:46:43 drh Exp $
+*/
+
+/*
+** Look up every table that is named in pSrc.  If any table is not found,
+** add an error message to pParse->zErrMsg and return NULL.  If all tables
+** are found, return a pointer to the last table.
+*/
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
+  Table *pTab = 0;
+  int i;
+  struct SrcList_item *pItem;
+  for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
+    pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
+    sqlite3DeleteTable(pItem->pTab);
+    pItem->pTab = pTab;
+    if( pTab ){
+      pTab->nRef++;
+    }
+  }
+  return pTab;
+}
+
+/*
+** Check to make sure the given table is writable.  If it is not
+** writable, generate an error message and return 1.  If it is
+** writable return 0;
+*/
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
+  if( (pTab->readOnly && (pParse->db->flags & SQLITE_WriteSchema)==0
+        && pParse->nested==0) 
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      || (pTab->pMod && pTab->pMod->pModule->xUpdate==0)
+#endif
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
+    return 1;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( !viewOk && pTab->pSelect ){
+    sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+/*
+** Generate code that will open a table for reading.
+*/
+SQLITE_PRIVATE void sqlite3OpenTable(
+  Parse *p,       /* Generate code into this VDBE */
+  int iCur,       /* The cursor number of the table */
+  int iDb,        /* The database index in sqlite3.aDb[] */
+  Table *pTab,    /* The table to be opened */
+  int opcode      /* OP_OpenRead or OP_OpenWrite */
+){
+  Vdbe *v;
+  if( IsVirtual(pTab) ) return;
+  v = sqlite3GetVdbe(p);
+  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
+  sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite), pTab->zName);
+  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
+  sqlite3VdbeAddOp3(v, opcode, iCur, pTab->tnum, iDb);
+  VdbeComment((v, "%s", pTab->zName));
+}
+
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+/*
+** Evaluate a view and store its result in an ephemeral table.  The
+** pWhere argument is an optional WHERE clause that restricts the
+** set of rows in the view that are to be added to the ephemeral table.
+*/
+SQLITE_PRIVATE void sqlite3MaterializeView(
+  Parse *pParse,       /* Parsing context */
+  Select *pView,       /* View definition */
+  Expr *pWhere,        /* Optional WHERE clause to be added */
+  int iCur             /* Cursor number for ephemerial table */
+){
+  SelectDest dest;
+  Select *pDup;
+  sqlite3 *db = pParse->db;
+
+  pDup = sqlite3SelectDup(db, pView);
+  if( pWhere ){
+    SrcList *pFrom;
+    
+    pWhere = sqlite3ExprDup(db, pWhere);
+    pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, 0, pDup, 0, 0);
+    pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
+  }
+  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
+  sqlite3Select(pParse, pDup, &dest, 0, 0, 0, 0);
+  sqlite3SelectDelete(pDup);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
+
+
+/*
+** Generate code for a DELETE FROM statement.
+**
+**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
+**                 \________/       \________________/
+**                  pTabList              pWhere
+*/
+SQLITE_PRIVATE void sqlite3DeleteFrom(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table from which we should delete things */
+  Expr *pWhere           /* The WHERE clause.  May be null */
+){
+  Vdbe *v;               /* The virtual database engine */
+  Table *pTab;           /* The table from which records will be deleted */
+  const char *zDb;       /* Name of database holding pTab */
+  int end, addr = 0;     /* A couple addresses of generated code */
+  int i;                 /* Loop counter */
+  WhereInfo *pWInfo;     /* Information about the WHERE clause */
+  Index *pIdx;           /* For looping over indices of the table */
+  int iCur;              /* VDBE Cursor number for pTab */
+  sqlite3 *db;           /* Main database structure */
+  AuthContext sContext;  /* Authorization context */
+  int oldIdx = -1;       /* Cursor for the OLD table of AFTER triggers */
+  NameContext sNC;       /* Name context to resolve expressions in */
+  int iDb;               /* Database number */
+  int memCnt = 0;        /* Memory cell used for change counting */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                  /* True if attempting to delete from a view */
+  int triggers_exist = 0;      /* True if any triggers exist */
+#endif
+  int iBeginAfterTrigger;      /* Address of after trigger program */
+  int iEndAfterTrigger;        /* Exit of after trigger program */
+  int iBeginBeforeTrigger;     /* Address of before trigger program */
+  int iEndBeforeTrigger;       /* Exit of before trigger program */
+  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
+
+  sContext.pParse = 0;
+  db = pParse->db;
+  if( pParse->nErr || db->mallocFailed ){
+    goto delete_from_cleanup;
+  }
+  assert( pTabList->nSrc==1 );
+
+  /* Locate the table which we want to delete.  This table has to be
+  ** put in an SrcList structure because some of the subroutines we
+  ** will be calling are designed to work with multiple tables and expect
+  ** an SrcList* parameter instead of just a Table* parameter.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 )  goto delete_from_cleanup;
+
+  /* Figure out if we have any triggers and if the table being
+  ** deleted from is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0);
+  isView = pTab->pSelect!=0;
+#else
+# define triggers_exist 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+    goto delete_from_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  zDb = db->aDb[iDb].zName;
+  if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
+    goto delete_from_cleanup;
+  }
+
+  /* If pTab is really a view, make sure it has been initialized.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto delete_from_cleanup;
+  }
+
+  /* Allocate a cursor used to store the old.* data for a trigger.
+  */
+  if( triggers_exist ){ 
+    oldIdx = pParse->nTab++;
+  }
+
+  /* Assign  cursor number to the table and all its indices.
+  */
+  assert( pTabList->nSrc==1 );
+  iCur = pTabList->a[0].iCursor = pParse->nTab++;
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    pParse->nTab++;
+  }
+
+  /* Start the view context
+  */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto delete_from_cleanup;
+  }
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, triggers_exist, iDb);
+
+  if( triggers_exist ){
+    int orconf = ((pParse->trigStack)?pParse->trigStack->orconf:OE_Default);
+    int iGoto = sqlite3VdbeAddOp0(v, OP_Goto);
+    addr = sqlite3VdbeMakeLabel(v);
+
+    iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
+    (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_BEFORE, pTab,
+        -1, oldIdx, orconf, addr, &old_col_mask, 0);
+    iEndBeforeTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
+
+    iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
+    (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_AFTER, pTab, -1,
+        oldIdx, orconf, addr, &old_col_mask, 0);
+    iEndAfterTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
+
+    sqlite3VdbeJumpHere(v, iGoto);
+  }
+
+  /* If we are trying to delete from a view, realize that view into
+  ** a ephemeral table.
+  */
+  if( isView ){
+    sqlite3MaterializeView(pParse, pTab->pSelect, pWhere, iCur);
+  }
+
+  /* Resolve the column names in the WHERE clause.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  if( sqlite3ExprResolveNames(&sNC, pWhere) ){
+    goto delete_from_cleanup;
+  }
+
+  /* Initialize the counter of the number of rows deleted, if
+  ** we are counting rows.
+  */
+  if( db->flags & SQLITE_CountRows ){
+    memCnt = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
+  }
+
+  /* Special case: A DELETE without a WHERE clause deletes everything.
+  ** It is easier just to erase the whole table.  Note, however, that
+  ** this means that the row change count will be incorrect.
+  */
+  if( pWhere==0 && !triggers_exist && !IsVirtual(pTab) ){
+    if( db->flags & SQLITE_CountRows ){
+      /* If counting rows deleted, just count the total number of
+      ** entries in the table. */
+      int addr2;
+      if( !isView ){
+        sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
+      }
+      sqlite3VdbeAddOp2(v, OP_Rewind, iCur, sqlite3VdbeCurrentAddr(v)+2);
+      addr2 = sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
+      sqlite3VdbeAddOp2(v, OP_Next, iCur, addr2);
+      sqlite3VdbeAddOp1(v, OP_Close, iCur);
+    }
+    if( !isView ){
+      sqlite3VdbeAddOp2(v, OP_Clear, pTab->tnum, iDb);
+      if( !pParse->nested ){
+        sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+      }
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        assert( pIdx->pSchema==pTab->pSchema );
+        sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
+      }
+    }
+  } 
+  /* The usual case: There is a WHERE clause so we have to scan through
+  ** the table and pick which records to delete.
+  */
+  else{
+    int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
+
+    /* Begin the database scan
+    */
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0);
+    if( pWInfo==0 ) goto delete_from_cleanup;
+
+    /* Remember the rowid of every item to be deleted.
+    */
+    sqlite3VdbeAddOp2(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid, iCur, iRowid);
+    sqlite3VdbeAddOp1(v, OP_FifoWrite, iRowid);
+    if( db->flags & SQLITE_CountRows ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
+    }
+
+    /* End the database scan loop.
+    */
+    sqlite3WhereEnd(pWInfo);
+
+    /* Open the pseudo-table used to store OLD if there are triggers.
+    */
+    if( triggers_exist ){
+      sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
+      sqlite3VdbeAddOp1(v, OP_OpenPseudo, oldIdx);
+    }
+
+    /* Delete every item whose key was written to the list during the
+    ** database scan.  We have to delete items after the scan is complete
+    ** because deleting an item can change the scan order.
+    */
+    end = sqlite3VdbeMakeLabel(v);
+
+    if( !isView ){
+      /* Open cursors for the table we are deleting from and 
+      ** all its indices.
+      */
+      sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
+    }
+
+    /* This is the beginning of the delete loop. If a trigger encounters
+    ** an IGNORE constraint, it jumps back to here.
+    */
+    if( triggers_exist ){
+      sqlite3VdbeResolveLabel(v, addr);
+    }
+    addr = sqlite3VdbeAddOp2(v, OP_FifoRead, iRowid, end);
+
+    if( triggers_exist ){
+      int iData = ++pParse->nMem;   /* For storing row data of OLD table */
+
+      /* If the record is no longer present in the table, jump to the
+      ** next iteration of the loop through the contents of the fifo.
+      */
+      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);
+
+      /* Populate the OLD.* pseudo-table */
+      if( old_col_mask ){
+        sqlite3VdbeAddOp2(v, OP_RowData, iCur, iData);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, iData);
+      }
+      sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, iData, iRowid);
+
+      /* Jump back and run the BEFORE triggers */
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
+      sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
+    }
+
+    if( !isView ){
+      /* Delete the row */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      if( IsVirtual(pTab) ){
+        const char *pVtab = (const char *)pTab->pVtab;
+        sqlite3VtabMakeWritable(pParse, pTab);
+        sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVtab, P4_VTAB);
+      }else
+#endif
+      {
+        sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, pParse->nested==0);
+      }
+    }
+
+    /* If there are row triggers, close all cursors then invoke
+    ** the AFTER triggers
+    */
+    if( triggers_exist ){
+      /* Jump back and run the AFTER triggers */
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
+      sqlite3VdbeJumpHere(v, iEndAfterTrigger);
+    }
+
+    /* End of the delete loop */
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+    sqlite3VdbeResolveLabel(v, end);
+
+    /* Close the cursors after the loop if there are no row triggers */
+    if( !isView  && !IsVirtual(pTab) ){
+      for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
+        sqlite3VdbeAddOp2(v, OP_Close, iCur + i, pIdx->tnum);
+      }
+      sqlite3VdbeAddOp1(v, OP_Close, iCur);
+    }
+  }
+
+  /*
+  ** Return the number of rows that were deleted. If this routine is 
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
+    sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", P4_STATIC);
+  }
+
+delete_from_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3SrcListDelete(pTabList);
+  sqlite3ExprDelete(pWhere);
+  return;
+}
+
+/*
+** This routine generates VDBE code that causes a single row of a
+** single table to be deleted.
+**
+** The VDBE must be in a particular state when this routine is called.
+** These are the requirements:
+**
+**   1.  A read/write cursor pointing to pTab, the table containing the row
+**       to be deleted, must be opened as cursor number "base".
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number base+i for the i-th index.
+**
+**   3.  The record number of the row to be deleted must be stored in
+**       memory cell iRowid.
+**
+** This routine pops the top of the stack to remove the record number
+** and then generates code to remove both the table record and all index
+** entries that point to that record.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  int iCur,          /* Cursor number for the table */
+  int iRowid,        /* Memory cell that contains the rowid to delete */
+  int count          /* Increment the row change counter */
+){
+  int addr;
+  Vdbe *v;
+
+  v = pParse->pVdbe;
+  addr = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowid);
+  sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0);
+  sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
+  if( count ){
+    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+  }
+  sqlite3VdbeJumpHere(v, addr);
+}
+
+/*
+** This routine generates VDBE code that causes the deletion of all
+** index entries associated with a single row of a single table.
+**
+** The VDBE must be in a particular state when this routine is called.
+** These are the requirements:
+**
+**   1.  A read/write cursor pointing to pTab, the table containing the row
+**       to be deleted, must be opened as cursor number "iCur".
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iCur+i for the i-th index.
+**
+**   3.  The "iCur" cursor must be pointing to the row that is to be
+**       deleted.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  int iCur,          /* Cursor number for the table */
+  int *aRegIdx       /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
+){
+  int i;
+  Index *pIdx;
+  int r1;
+
+  for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
+    if( aRegIdx!=0 && aRegIdx[i-1]==0 ) continue;
+    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iCur, 0, 0);
+    sqlite3VdbeAddOp3(pParse->pVdbe, OP_IdxDelete, iCur+i, r1,pIdx->nColumn+1);
+  }
+}
+
+/*
+** Generate code that will assemble an index key and put it in register
+** regOut.  The key with be for index pIdx which is an index on pTab.
+** iCur is the index of a cursor open on the pTab table and pointing to
+** the entry that needs indexing.
+**
+** Return a register number which is the first in a block of
+** registers that holds the elements of the index key.  The
+** block of registers has already been deallocated by the time
+** this routine returns.
+*/
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(
+  Parse *pParse,     /* Parsing context */
+  Index *pIdx,       /* The index for which to generate a key */
+  int iCur,          /* Cursor number for the pIdx->pTable table */
+  int regOut,        /* Write the new index key to this register */
+  int doMakeRec      /* Run the OP_MakeRecord instruction if true */
+){
+  Vdbe *v = pParse->pVdbe;
+  int j;
+  Table *pTab = pIdx->pTable;
+  int regBase;
+  int nCol;
+
+  nCol = pIdx->nColumn;
+  regBase = sqlite3GetTempRange(pParse, nCol+1);
+  sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regBase+nCol);
+  for(j=0; j<nCol; j++){
+    int idx = pIdx->aiColumn[j];
+    if( idx==pTab->iPKey ){
+      sqlite3VdbeAddOp2(v, OP_SCopy, regBase+nCol, regBase+j);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, iCur, idx, regBase+j);
+      sqlite3ColumnDefault(v, pTab, idx);
+    }
+  }
+  if( doMakeRec ){
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol+1, regOut);
+    sqlite3IndexAffinityStr(v, pIdx);
+    sqlite3ExprCacheAffinityChange(pParse, regBase, nCol+1);
+  }
+  sqlite3ReleaseTempRange(pParse, regBase, nCol+1);
+  return regBase;
+}
+
+/* Make sure "isView" gets undefined in case this file becomes part of
+** the amalgamation - so that subsequent files do not see isView as a
+** macro. */
+#undef isView
+
+/************** End of delete.c **********************************************/
+/************** Begin file func.c ********************************************/
+/*
+** 2002 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement various SQL
+** functions of SQLite.  
+**
+** There is only one exported symbol in this file - the function
+** sqliteRegisterBuildinFunctions() found at the bottom of the file.
+** All other code has file scope.
+**
+** $Id: func.c,v 1.192 2008/04/27 18:40:12 drh Exp $
+*/
+
+
+/*
+** Return the collating function associated with a function.
+*/
+static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
+  return context->pColl;
+}
+
+/*
+** Implementation of the non-aggregate min() and max() functions
+*/
+static void minmaxFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  int mask;    /* 0 for min() or 0xffffffff for max() */
+  int iBest;
+  CollSeq *pColl;
+
+  if( argc==0 ) return;
+  mask = sqlite3_user_data(context)==0 ? 0 : -1;
+  pColl = sqlite3GetFuncCollSeq(context);
+  assert( pColl );
+  assert( mask==-1 || mask==0 );
+  iBest = 0;
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  for(i=1; i<argc; i++){
+    if( sqlite3_value_type(argv[i])==SQLITE_NULL ) return;
+    if( (sqlite3MemCompare(argv[iBest], argv[i], pColl)^mask)>=0 ){
+      iBest = i;
+    }
+  }
+  sqlite3_result_value(context, argv[iBest]);
+}
+
+/*
+** Return the type of the argument.
+*/
+static void typeofFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *z = 0;
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_NULL:    z = "null";    break;
+    case SQLITE_INTEGER: z = "integer"; break;
+    case SQLITE_TEXT:    z = "text";    break;
+    case SQLITE_FLOAT:   z = "real";    break;
+    case SQLITE_BLOB:    z = "blob";    break;
+  }
+  sqlite3_result_text(context, z, -1, SQLITE_STATIC);
+}
+
+
+/*
+** Implementation of the length() function
+*/
+static void lengthFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int len;
+
+  assert( argc==1 );
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB:
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *z = sqlite3_value_text(argv[0]);
+      if( z==0 ) return;
+      len = 0;
+      while( *z ){
+        len++;
+        SQLITE_SKIP_UTF8(z);
+      }
+      sqlite3_result_int(context, len);
+      break;
+    }
+    default: {
+      sqlite3_result_null(context);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the abs() function
+*/
+static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  assert( argc==1 );
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_INTEGER: {
+      i64 iVal = sqlite3_value_int64(argv[0]);
+      if( iVal<0 ){
+        if( (iVal<<1)==0 ){
+          sqlite3_result_error(context, "integer overflow", -1);
+          return;
+        }
+        iVal = -iVal;
+      } 
+      sqlite3_result_int64(context, iVal);
+      break;
+    }
+    case SQLITE_NULL: {
+      sqlite3_result_null(context);
+      break;
+    }
+    default: {
+      double rVal = sqlite3_value_double(argv[0]);
+      if( rVal<0 ) rVal = -rVal;
+      sqlite3_result_double(context, rVal);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the substr() function.
+**
+** substr(x,p1,p2)  returns p2 characters of x[] beginning with p1.
+** p1 is 1-indexed.  So substr(x,1,1) returns the first character
+** of x.  If x is text, then we actually count UTF-8 characters.
+** If x is a blob, then we count bytes.
+**
+** If p1 is negative, then we begin abs(p1) from the end of x[].
+*/
+static void substrFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *z;
+  const unsigned char *z2;
+  int len;
+  int p0type;
+  i64 p1, p2;
+
+  assert( argc==3 || argc==2 );
+  p0type = sqlite3_value_type(argv[0]);
+  if( p0type==SQLITE_BLOB ){
+    len = sqlite3_value_bytes(argv[0]);
+    z = sqlite3_value_blob(argv[0]);
+    if( z==0 ) return;
+    assert( len==sqlite3_value_bytes(argv[0]) );
+  }else{
+    z = sqlite3_value_text(argv[0]);
+    if( z==0 ) return;
+    len = 0;
+    for(z2=z; *z2; len++){
+      SQLITE_SKIP_UTF8(z2);
+    }
+  }
+  p1 = sqlite3_value_int(argv[1]);
+  if( argc==3 ){
+    p2 = sqlite3_value_int(argv[2]);
+  }else{
+    p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  if( p1<0 ){
+    p1 += len;
+    if( p1<0 ){
+      p2 += p1;
+      p1 = 0;
+    }
+  }else if( p1>0 ){
+    p1--;
+  }
+  if( p1+p2>len ){
+    p2 = len-p1;
+  }
+  if( p0type!=SQLITE_BLOB ){
+    while( *z && p1 ){
+      SQLITE_SKIP_UTF8(z);
+      p1--;
+    }
+    for(z2=z; *z2 && p2; p2--){
+      SQLITE_SKIP_UTF8(z2);
+    }
+    sqlite3_result_text(context, (char*)z, z2-z, SQLITE_TRANSIENT);
+  }else{
+    if( p2<0 ) p2 = 0;
+    sqlite3_result_blob(context, (char*)&z[p1], p2, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+** Implementation of the round() function
+*/
+static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  int n = 0;
+  double r;
+  char zBuf[500];  /* larger than the %f representation of the largest double */
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
+    n = sqlite3_value_int(argv[1]);
+    if( n>30 ) n = 30;
+    if( n<0 ) n = 0;
+  }
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  r = sqlite3_value_double(argv[0]);
+  sqlite3_snprintf(sizeof(zBuf),zBuf,"%.*f",n,r);
+  sqlite3AtoF(zBuf, &r);
+  sqlite3_result_double(context, r);
+}
+
+/*
+** Allocate nByte bytes of space using sqlite3_malloc(). If the
+** allocation fails, call sqlite3_result_error_nomem() to notify
+** the database handle that malloc() has failed.
+*/
+static void *contextMalloc(sqlite3_context *context, i64 nByte){
+  char *z;
+  if( nByte>sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(context);
+    z = 0;
+  }else{
+    z = sqlite3_malloc(nByte);
+    if( !z && nByte>0 ){
+      sqlite3_result_error_nomem(context);
+    }
+  }
+  return z;
+}
+
+/*
+** Implementation of the upper() and lower() SQL functions.
+*/
+static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      memcpy(z1, z2, n+1);
+      for(i=0; z1[i]; i++){
+        z1[i] = toupper(z1[i]);
+      }
+      sqlite3_result_text(context, z1, -1, sqlite3_free);
+    }
+  }
+}
+static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      memcpy(z1, z2, n+1);
+      for(i=0; z1[i]; i++){
+        z1[i] = tolower(z1[i]);
+      }
+      sqlite3_result_text(context, z1, -1, sqlite3_free);
+    }
+  }
+}
+
+/*
+** Implementation of the IFNULL(), NVL(), and COALESCE() functions.  
+** All three do the same thing.  They return the first non-NULL
+** argument.
+*/
+static void ifnullFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  for(i=0; i<argc; i++){
+    if( SQLITE_NULL!=sqlite3_value_type(argv[i]) ){
+      sqlite3_result_value(context, argv[i]);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of random().  Return a random integer.  
+*/
+static void randomFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite_int64 r;
+  sqlite3_randomness(sizeof(r), &r);
+  if( (r<<1)==0 ) r = 0;  /* Prevent 0x8000.... as the result so that we */
+                          /* can always do abs() of the result */
+  sqlite3_result_int64(context, r);
+}
+
+/*
+** Implementation of randomblob(N).  Return a random blob
+** that is N bytes long.
+*/
+static void randomBlob(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int n;
+  unsigned char *p;
+  assert( argc==1 );
+  n = sqlite3_value_int(argv[0]);
+  if( n<1 ){
+    n = 1;
+  }
+  p = contextMalloc(context, n);
+  if( p ){
+    sqlite3_randomness(n, p);
+    sqlite3_result_blob(context, (char*)p, n, sqlite3_free);
+  }
+}
+
+/*
+** Implementation of the last_insert_rowid() SQL function.  The return
+** value is the same as the sqlite3_last_insert_rowid() API function.
+*/
+static void last_insert_rowid(
+  sqlite3_context *context, 
+  int arg, 
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
+}
+
+/*
+** Implementation of the changes() SQL function.  The return value is the
+** same as the sqlite3_changes() API function.
+*/
+static void changes(
+  sqlite3_context *context,
+  int arg,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  sqlite3_result_int(context, sqlite3_changes(db));
+}
+
+/*
+** Implementation of the total_changes() SQL function.  The return value is
+** the same as the sqlite3_total_changes() API function.
+*/
+static void total_changes(
+  sqlite3_context *context,
+  int arg,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  sqlite3_result_int(context, sqlite3_total_changes(db));
+}
+
+/*
+** A structure defining how to do GLOB-style comparisons.
+*/
+struct compareInfo {
+  u8 matchAll;
+  u8 matchOne;
+  u8 matchSet;
+  u8 noCase;
+};
+
+/*
+** For LIKE and GLOB matching on EBCDIC machines, assume that every
+** character is exactly one byte in size.  Also, all characters are
+** able to participate in upper-case-to-lower-case mappings in EBCDIC
+** whereas only characters less than 0x80 do in ASCII.
+*/
+#if defined(SQLITE_EBCDIC)
+# define sqlite3Utf8Read(A,B,C)  (*(A++))
+# define GlogUpperToLower(A)     A = sqlite3UpperToLower[A]
+#else
+# define GlogUpperToLower(A)     if( A<0x80 ){ A = sqlite3UpperToLower[A]; }
+#endif
+
+static const struct compareInfo globInfo = { '*', '?', '[', 0 };
+/* The correct SQL-92 behavior is for the LIKE operator to ignore
+** case.  Thus  'a' LIKE 'A' would be true. */
+static const struct compareInfo likeInfoNorm = { '%', '_',   0, 1 };
+/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
+** is case sensitive causing 'a' LIKE 'A' to be false */
+static const struct compareInfo likeInfoAlt = { '%', '_',   0, 0 };
+
+/*
+** Compare two UTF-8 strings for equality where the first string can
+** potentially be a "glob" expression.  Return true (1) if they
+** are the same and false (0) if they are different.
+**
+** Globbing rules:
+**
+**      '*'       Matches any sequence of zero or more characters.
+**
+**      '?'       Matches exactly one character.
+**
+**     [...]      Matches one character from the enclosed list of
+**                characters.
+**
+**     [^...]     Matches one character not in the enclosed list.
+**
+** With the [...] and [^...] matching, a ']' character can be included
+** in the list by making it the first character after '[' or '^'.  A
+** range of characters can be specified using '-'.  Example:
+** "[a-z]" matches any single lower-case letter.  To match a '-', make
+** it the last character in the list.
+**
+** This routine is usually quick, but can be N**2 in the worst case.
+**
+** Hints: to match '*' or '?', put them in "[]".  Like this:
+**
+**         abc[*]xyz        Matches "abc*xyz" only
+*/
+static int patternCompare(
+  const u8 *zPattern,              /* The glob pattern */
+  const u8 *zString,               /* The string to compare against the glob */
+  const struct compareInfo *pInfo, /* Information about how to do the compare */
+  const int esc                    /* The escape character */
+){
+  int c, c2;
+  int invert;
+  int seen;
+  u8 matchOne = pInfo->matchOne;
+  u8 matchAll = pInfo->matchAll;
+  u8 matchSet = pInfo->matchSet;
+  u8 noCase = pInfo->noCase; 
+  int prevEscape = 0;     /* True if the previous character was 'escape' */
+
+  while( (c = sqlite3Utf8Read(zPattern,0,&zPattern))!=0 ){
+    if( !prevEscape && c==matchAll ){
+      while( (c=sqlite3Utf8Read(zPattern,0,&zPattern)) == matchAll
+               || c == matchOne ){
+        if( c==matchOne && sqlite3Utf8Read(zString, 0, &zString)==0 ){
+          return 0;
+        }
+      }
+      if( c==0 ){
+        return 1;
+      }else if( c==esc ){
+        c = sqlite3Utf8Read(zPattern, 0, &zPattern);
+        if( c==0 ){
+          return 0;
+        }
+      }else if( c==matchSet ){
+        assert( esc==0 );         /* This is GLOB, not LIKE */
+        assert( matchSet<0x80 );  /* '[' is a single-byte character */
+        while( *zString && patternCompare(&zPattern[-1],zString,pInfo,esc)==0 ){
+          SQLITE_SKIP_UTF8(zString);
+        }
+        return *zString!=0;
+      }
+      while( (c2 = sqlite3Utf8Read(zString,0,&zString))!=0 ){
+        if( noCase ){
+          GlogUpperToLower(c2);
+          GlogUpperToLower(c);
+          while( c2 != 0 && c2 != c ){
+            c2 = sqlite3Utf8Read(zString, 0, &zString);
+            GlogUpperToLower(c2);
+          }
+        }else{
+          while( c2 != 0 && c2 != c ){
+            c2 = sqlite3Utf8Read(zString, 0, &zString);
+          }
+        }
+        if( c2==0 ) return 0;
+        if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
+      }
+      return 0;
+    }else if( !prevEscape && c==matchOne ){
+      if( sqlite3Utf8Read(zString, 0, &zString)==0 ){
+        return 0;
+      }
+    }else if( c==matchSet ){
+      int prior_c = 0;
+      assert( esc==0 );    /* This only occurs for GLOB, not LIKE */
+      seen = 0;
+      invert = 0;
+      c = sqlite3Utf8Read(zString, 0, &zString);
+      if( c==0 ) return 0;
+      c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+      if( c2=='^' ){
+        invert = 1;
+        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+      }
+      if( c2==']' ){
+        if( c==']' ) seen = 1;
+        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+      }
+      while( c2 && c2!=']' ){
+        if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
+          c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+          if( c>=prior_c && c<=c2 ) seen = 1;
+          prior_c = 0;
+        }else{
+          if( c==c2 ){
+            seen = 1;
+          }
+          prior_c = c2;
+        }
+        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+      }
+      if( c2==0 || (seen ^ invert)==0 ){
+        return 0;
+      }
+    }else if( esc==c && !prevEscape ){
+      prevEscape = 1;
+    }else{
+      c2 = sqlite3Utf8Read(zString, 0, &zString);
+      if( noCase ){
+        GlogUpperToLower(c);
+        GlogUpperToLower(c2);
+      }
+      if( c!=c2 ){
+        return 0;
+      }
+      prevEscape = 0;
+    }
+  }
+  return *zString==0;
+}
+
+/*
+** Count the number of times that the LIKE operator (or GLOB which is
+** just a variation of LIKE) gets called.  This is used for testing
+** only.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_like_count = 0;
+#endif
+
+
+/*
+** Implementation of the like() SQL function.  This function implements
+** the build-in LIKE operator.  The first argument to the function is the
+** pattern and the second argument is the string.  So, the SQL statements:
+**
+**       A LIKE B
+**
+** is implemented as like(B,A).
+**
+** This same function (with a different compareInfo structure) computes
+** the GLOB operator.
+*/
+static void likeFunc(
+  sqlite3_context *context, 
+  int argc, 
+  sqlite3_value **argv
+){
+  const unsigned char *zA, *zB;
+  int escape = 0;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  zB = sqlite3_value_text(argv[0]);
+  zA = sqlite3_value_text(argv[1]);
+
+  /* Limit the length of the LIKE or GLOB pattern to avoid problems
+  ** of deep recursion and N*N behavior in patternCompare().
+  */
+  if( sqlite3_value_bytes(argv[0]) >
+        db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
+    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
+    return;
+  }
+  assert( zB==sqlite3_value_text(argv[0]) );  /* Encoding did not change */
+
+  if( argc==3 ){
+    /* The escape character string must consist of a single UTF-8 character.
+    ** Otherwise, return an error.
+    */
+    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
+    if( zEsc==0 ) return;
+    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
+      sqlite3_result_error(context, 
+          "ESCAPE expression must be a single character", -1);
+      return;
+    }
+    escape = sqlite3Utf8Read(zEsc, 0, &zEsc);
+  }
+  if( zA && zB ){
+    struct compareInfo *pInfo = sqlite3_user_data(context);
+#ifdef SQLITE_TEST
+    sqlite3_like_count++;
+#endif
+    
+    sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape));
+  }
+}
+
+/*
+** Implementation of the NULLIF(x,y) function.  The result is the first
+** argument if the arguments are different.  The result is NULL if the
+** arguments are equal to each other.
+*/
+static void nullifFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+  if( sqlite3MemCompare(argv[0], argv[1], pColl)!=0 ){
+    sqlite3_result_value(context, argv[0]);
+  }
+}
+
+/*
+** Implementation of the VERSION(*) function.  The result is the version
+** of the SQLite library that is running.
+*/
+static void versionFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_result_text(context, sqlite3_version, -1, SQLITE_STATIC);
+}
+
+/* Array for converting from half-bytes (nybbles) into ASCII hex
+** digits. */
+static const char hexdigits[] = {
+  '0', '1', '2', '3', '4', '5', '6', '7',
+  '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' 
+};
+
+/*
+** EXPERIMENTAL - This is not an official function.  The interface may
+** change.  This function may disappear.  Do not write code that depends
+** on this function.
+**
+** Implementation of the QUOTE() function.  This function takes a single
+** argument.  If the argument is numeric, the return value is the same as
+** the argument.  If the argument is NULL, the return value is the string
+** "NULL".  Otherwise, the argument is enclosed in single quotes with
+** single-quote escapes.
+*/
+static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  if( argc<1 ) return;
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_NULL: {
+      sqlite3_result_text(context, "NULL", 4, SQLITE_STATIC);
+      break;
+    }
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      sqlite3_result_value(context, argv[0]);
+      break;
+    }
+    case SQLITE_BLOB: {
+      char *zText = 0;
+      char const *zBlob = sqlite3_value_blob(argv[0]);
+      int nBlob = sqlite3_value_bytes(argv[0]);
+      assert( zBlob==sqlite3_value_blob(argv[0]) ); /* No encoding change */
+      zText = (char *)contextMalloc(context, (2*(i64)nBlob)+4); 
+      if( zText ){
+        int i;
+        for(i=0; i<nBlob; i++){
+          zText[(i*2)+2] = hexdigits[(zBlob[i]>>4)&0x0F];
+          zText[(i*2)+3] = hexdigits[(zBlob[i])&0x0F];
+        }
+        zText[(nBlob*2)+2] = '\'';
+        zText[(nBlob*2)+3] = '\0';
+        zText[0] = 'X';
+        zText[1] = '\'';
+        sqlite3_result_text(context, zText, -1, SQLITE_TRANSIENT);
+        sqlite3_free(zText);
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      int i,j;
+      u64 n;
+      const unsigned char *zArg = sqlite3_value_text(argv[0]);
+      char *z;
+
+      if( zArg==0 ) return;
+      for(i=0, n=0; zArg[i]; i++){ if( zArg[i]=='\'' ) n++; }
+      z = contextMalloc(context, ((i64)i)+((i64)n)+3);
+      if( z ){
+        z[0] = '\'';
+        for(i=0, j=1; zArg[i]; i++){
+          z[j++] = zArg[i];
+          if( zArg[i]=='\'' ){
+            z[j++] = '\'';
+          }
+        }
+        z[j++] = '\'';
+        z[j] = 0;
+        sqlite3_result_text(context, z, j, sqlite3_free);
+      }
+    }
+  }
+}
+
+/*
+** The hex() function.  Interpret the argument as a blob.  Return
+** a hexadecimal rendering as text.
+*/
+static void hexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i, n;
+  const unsigned char *pBlob;
+  char *zHex, *z;
+  assert( argc==1 );
+  pBlob = sqlite3_value_blob(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  assert( pBlob==sqlite3_value_blob(argv[0]) );  /* No encoding change */
+  z = zHex = contextMalloc(context, ((i64)n)*2 + 1);
+  if( zHex ){
+    for(i=0; i<n; i++, pBlob++){
+      unsigned char c = *pBlob;
+      *(z++) = hexdigits[(c>>4)&0xf];
+      *(z++) = hexdigits[c&0xf];
+    }
+    *z = 0;
+    sqlite3_result_text(context, zHex, n*2, sqlite3_free);
+  }
+}
+
+/*
+** The zeroblob(N) function returns a zero-filled blob of size N bytes.
+*/
+static void zeroblobFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  i64 n;
+  assert( argc==1 );
+  n = sqlite3_value_int64(argv[0]);
+  if( n>SQLITE_MAX_LENGTH ){
+    sqlite3_result_error_toobig(context);
+  }else{
+    sqlite3_result_zeroblob(context, n);
+  }
+}
+
+/*
+** The replace() function.  Three arguments are all strings: call
+** them A, B, and C. The result is also a string which is derived
+** from A by replacing every occurance of B with C.  The match
+** must be exact.  Collating sequences are not used.
+*/
+static void replaceFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zStr;        /* The input string A */
+  const unsigned char *zPattern;    /* The pattern string B */
+  const unsigned char *zRep;        /* The replacement string C */
+  unsigned char *zOut;              /* The output */
+  int nStr;                /* Size of zStr */
+  int nPattern;            /* Size of zPattern */
+  int nRep;                /* Size of zRep */
+  i64 nOut;                /* Maximum size of zOut */
+  int loopLimit;           /* Last zStr[] that might match zPattern[] */
+  int i, j;                /* Loop counters */
+
+  assert( argc==3 );
+  zStr = sqlite3_value_text(argv[0]);
+  if( zStr==0 ) return;
+  nStr = sqlite3_value_bytes(argv[0]);
+  assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
+  zPattern = sqlite3_value_text(argv[1]);
+  if( zPattern==0 || zPattern[0]==0 ) return;
+  nPattern = sqlite3_value_bytes(argv[1]);
+  assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
+  zRep = sqlite3_value_text(argv[2]);
+  if( zRep==0 ) return;
+  nRep = sqlite3_value_bytes(argv[2]);
+  assert( zRep==sqlite3_value_text(argv[2]) );
+  nOut = nStr + 1;
+  assert( nOut<SQLITE_MAX_LENGTH );
+  zOut = contextMalloc(context, (i64)nOut);
+  if( zOut==0 ){
+    return;
+  }
+  loopLimit = nStr - nPattern;  
+  for(i=j=0; i<=loopLimit; i++){
+    if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
+      zOut[j++] = zStr[i];
+    }else{
+      u8 *zOld;
+      sqlite3 *db = sqlite3_context_db_handle(context);
+      nOut += nRep - nPattern;
+      if( nOut>=db->aLimit[SQLITE_LIMIT_LENGTH] ){
+        sqlite3_result_error_toobig(context);
+        sqlite3_free(zOut);
+        return;
+      }
+      zOld = zOut;
+      zOut = sqlite3_realloc(zOut, (int)nOut);
+      if( zOut==0 ){
+        sqlite3_result_error_nomem(context);
+        sqlite3_free(zOld);
+        return;
+      }
+      memcpy(&zOut[j], zRep, nRep);
+      j += nRep;
+      i += nPattern-1;
+    }
+  }
+  assert( j+nStr-i+1==nOut );
+  memcpy(&zOut[j], &zStr[i], nStr-i);
+  j += nStr - i;
+  assert( j<=nOut );
+  zOut[j] = 0;
+  sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
+}
+
+/*
+** Implementation of the TRIM(), LTRIM(), and RTRIM() functions.
+** The userdata is 0x1 for left trim, 0x2 for right trim, 0x3 for both.
+*/
+static void trimFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zIn;         /* Input string */
+  const unsigned char *zCharSet;    /* Set of characters to trim */
+  int nIn;                          /* Number of bytes in input */
+  int flags;                        /* 1: trimleft  2: trimright  3: trim */
+  int i;                            /* Loop counter */
+  unsigned char *aLen;              /* Length of each character in zCharSet */
+  unsigned char **azChar;           /* Individual characters in zCharSet */
+  int nChar;                        /* Number of characters in zCharSet */
+
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    return;
+  }
+  zIn = sqlite3_value_text(argv[0]);
+  if( zIn==0 ) return;
+  nIn = sqlite3_value_bytes(argv[0]);
+  assert( zIn==sqlite3_value_text(argv[0]) );
+  if( argc==1 ){
+    static const unsigned char lenOne[] = { 1 };
+    static const unsigned char *azOne[] = { (u8*)" " };
+    nChar = 1;
+    aLen = (u8*)lenOne;
+    azChar = (unsigned char **)azOne;
+    zCharSet = 0;
+  }else if( (zCharSet = sqlite3_value_text(argv[1]))==0 ){
+    return;
+  }else{
+    const unsigned char *z;
+    for(z=zCharSet, nChar=0; *z; nChar++){
+      SQLITE_SKIP_UTF8(z);
+    }
+    if( nChar>0 ){
+      azChar = contextMalloc(context, ((i64)nChar)*(sizeof(char*)+1));
+      if( azChar==0 ){
+        return;
+      }
+      aLen = (unsigned char*)&azChar[nChar];
+      for(z=zCharSet, nChar=0; *z; nChar++){
+        azChar[nChar] = (unsigned char *)z;
+        SQLITE_SKIP_UTF8(z);
+        aLen[nChar] = z - azChar[nChar];
+      }
+    }
+  }
+  if( nChar>0 ){
+    flags = (int)sqlite3_user_data(context);
+    if( flags & 1 ){
+      while( nIn>0 ){
+        int len;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( memcmp(zIn, azChar[i], len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        zIn += len;
+        nIn -= len;
+      }
+    }
+    if( flags & 2 ){
+      while( nIn>0 ){
+        int len;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( len<=nIn && memcmp(&zIn[nIn-len],azChar[i],len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        nIn -= len;
+      }
+    }
+    if( zCharSet ){
+      sqlite3_free(azChar);
+    }
+  }
+  sqlite3_result_text(context, (char*)zIn, nIn, SQLITE_TRANSIENT);
+}
+
+#ifdef SQLITE_SOUNDEX
+/*
+** Compute the soundex encoding of a word.
+*/
+static void soundexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  char zResult[8];
+  const u8 *zIn;
+  int i, j;
+  static const unsigned char iCode[] = {
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+  };
+  assert( argc==1 );
+  zIn = (u8*)sqlite3_value_text(argv[0]);
+  if( zIn==0 ) zIn = (u8*)"";
+  for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
+  if( zIn[i] ){
+    u8 prevcode = iCode[zIn[i]&0x7f];
+    zResult[0] = toupper(zIn[i]);
+    for(j=1; j<4 && zIn[i]; i++){
+      int code = iCode[zIn[i]&0x7f];
+      if( code>0 ){
+        if( code!=prevcode ){
+          prevcode = code;
+          zResult[j++] = code + '0';
+        }
+      }else{
+        prevcode = 0;
+      }
+    }
+    while( j<4 ){
+      zResult[j++] = '0';
+    }
+    zResult[j] = 0;
+    sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
+  }
+}
+#endif
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** A function that loads a shared-library extension then returns NULL.
+*/
+static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
+  const char *zFile = (const char *)sqlite3_value_text(argv[0]);
+  const char *zProc;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char *zErrMsg = 0;
+
+  if( argc==2 ){
+    zProc = (const char *)sqlite3_value_text(argv[1]);
+  }else{
+    zProc = 0;
+  }
+  if( zFile && sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
+    sqlite3_result_error(context, zErrMsg, -1);
+    sqlite3_free(zErrMsg);
+  }
+}
+#endif
+
+
+/*
+** An instance of the following structure holds the context of a
+** sum() or avg() aggregate computation.
+*/
+typedef struct SumCtx SumCtx;
+struct SumCtx {
+  double rSum;      /* Floating point sum */
+  i64 iSum;         /* Integer sum */   
+  i64 cnt;          /* Number of elements summed */
+  u8 overflow;      /* True if integer overflow seen */
+  u8 approx;        /* True if non-integer value was input to the sum */
+};
+
+/*
+** Routines used to compute the sum, average, and total.
+**
+** The SUM() function follows the (broken) SQL standard which means
+** that it returns NULL if it sums over no inputs.  TOTAL returns
+** 0.0 in that case.  In addition, TOTAL always returns a float where
+** SUM might return an integer if it never encounters a floating point
+** value.  TOTAL never fails, but SUM might through an exception if
+** it overflows an integer.
+*/
+static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  SumCtx *p;
+  int type;
+  assert( argc==1 );
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  type = sqlite3_value_numeric_type(argv[0]);
+  if( p && type!=SQLITE_NULL ){
+    p->cnt++;
+    if( type==SQLITE_INTEGER ){
+      i64 v = sqlite3_value_int64(argv[0]);
+      p->rSum += v;
+      if( (p->approx|p->overflow)==0 ){
+        i64 iNewSum = p->iSum + v;
+        int s1 = p->iSum >> (sizeof(i64)*8-1);
+        int s2 = v       >> (sizeof(i64)*8-1);
+        int s3 = iNewSum >> (sizeof(i64)*8-1);
+        p->overflow = (s1&s2&~s3) | (~s1&~s2&s3);
+        p->iSum = iNewSum;
+      }
+    }else{
+      p->rSum += sqlite3_value_double(argv[0]);
+      p->approx = 1;
+    }
+  }
+}
+static void sumFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    if( p->overflow ){
+      sqlite3_result_error(context,"integer overflow",-1);
+    }else if( p->approx ){
+      sqlite3_result_double(context, p->rSum);
+    }else{
+      sqlite3_result_int64(context, p->iSum);
+    }
+  }
+}
+static void avgFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    sqlite3_result_double(context, p->rSum/(double)p->cnt);
+  }
+}
+static void totalFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  sqlite3_result_double(context, p ? p->rSum : 0.0);
+}
+
+/*
+** The following structure keeps track of state information for the
+** count() aggregate function.
+*/
+typedef struct CountCtx CountCtx;
+struct CountCtx {
+  i64 n;
+};
+
+/*
+** Routines to implement the count() aggregate function.
+*/
+static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && p ){
+    p->n++;
+  }
+}   
+static void countFinalize(sqlite3_context *context){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  sqlite3_result_int64(context, p ? p->n : 0);
+}
+
+/*
+** Routines to implement min() and max() aggregate functions.
+*/
+static void minmaxStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  Mem *pArg  = (Mem *)argv[0];
+  Mem *pBest;
+
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));
+  if( !pBest ) return;
+
+  if( pBest->flags ){
+    int max;
+    int cmp;
+    CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+    /* This step function is used for both the min() and max() aggregates,
+    ** the only difference between the two being that the sense of the
+    ** comparison is inverted. For the max() aggregate, the
+    ** sqlite3_user_data() function returns (void *)-1. For min() it
+    ** returns (void *)db, where db is the sqlite3* database pointer.
+    ** Therefore the next statement sets variable 'max' to 1 for the max()
+    ** aggregate, or 0 for min().
+    */
+    max = sqlite3_user_data(context)!=0;
+    cmp = sqlite3MemCompare(pBest, pArg, pColl);
+    if( (max && cmp<0) || (!max && cmp>0) ){
+      sqlite3VdbeMemCopy(pBest, pArg);
+    }
+  }else{
+    sqlite3VdbeMemCopy(pBest, pArg);
+  }
+}
+static void minMaxFinalize(sqlite3_context *context){
+  sqlite3_value *pRes;
+  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
+  if( pRes ){
+    if( pRes->flags ){
+      sqlite3_result_value(context, pRes);
+    }
+    sqlite3VdbeMemRelease(pRes);
+  }
+}
+
+/*
+** group_concat(EXPR, ?SEPARATOR?)
+*/
+static void groupConcatStep(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zVal;
+  StrAccum *pAccum;
+  const char *zSep;
+  int nVal, nSep;
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pAccum = (StrAccum*)sqlite3_aggregate_context(context, sizeof(*pAccum));
+
+  if( pAccum ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    pAccum->useMalloc = 1;
+    pAccum->mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
+    if( pAccum->nChar ){
+      if( argc==2 ){
+        zSep = (char*)sqlite3_value_text(argv[1]);
+        nSep = sqlite3_value_bytes(argv[1]);
+      }else{
+        zSep = ",";
+        nSep = 1;
+      }
+      sqlite3StrAccumAppend(pAccum, zSep, nSep);
+    }
+    zVal = (char*)sqlite3_value_text(argv[0]);
+    nVal = sqlite3_value_bytes(argv[0]);
+    sqlite3StrAccumAppend(pAccum, zVal, nVal);
+  }
+}
+static void groupConcatFinalize(sqlite3_context *context){
+  StrAccum *pAccum;
+  pAccum = sqlite3_aggregate_context(context, 0);
+  if( pAccum ){
+    if( pAccum->tooBig ){
+      sqlite3_result_error_toobig(context);
+    }else if( pAccum->mallocFailed ){
+      sqlite3_result_error_nomem(context);
+    }else{    
+      sqlite3_result_text(context, sqlite3StrAccumFinish(pAccum), -1, 
+                          sqlite3_free);
+    }
+  }
+}
+
+/*
+** This function registered all of the above C functions as SQL
+** functions.  This should be the only routine in this file with
+** external linkage.
+*/
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(sqlite3 *db){
+  static const struct {
+     char *zName;
+     signed char nArg;
+     u8 argType;           /* 1: 0, 2: 1, 3: 2,...  N:  N-1. */
+     u8 eTextRep;          /* 1: UTF-16.  0: UTF-8 */
+     u8 needCollSeq;
+     void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
+  } aFuncs[] = {
+    { "min",               -1, 0, SQLITE_UTF8,    1, minmaxFunc },
+    { "min",                0, 0, SQLITE_UTF8,    1, 0          },
+    { "max",               -1, 1, SQLITE_UTF8,    1, minmaxFunc },
+    { "max",                0, 1, SQLITE_UTF8,    1, 0          },
+    { "typeof",             1, 0, SQLITE_UTF8,    0, typeofFunc },
+    { "length",             1, 0, SQLITE_UTF8,    0, lengthFunc },
+    { "substr",             2, 0, SQLITE_UTF8,    0, substrFunc },
+    { "substr",             3, 0, SQLITE_UTF8,    0, substrFunc },
+    { "abs",                1, 0, SQLITE_UTF8,    0, absFunc    },
+    { "round",              1, 0, SQLITE_UTF8,    0, roundFunc  },
+    { "round",              2, 0, SQLITE_UTF8,    0, roundFunc  },
+    { "upper",              1, 0, SQLITE_UTF8,    0, upperFunc  },
+    { "lower",              1, 0, SQLITE_UTF8,    0, lowerFunc  },
+    { "coalesce",          -1, 0, SQLITE_UTF8,    0, ifnullFunc },
+    { "coalesce",           0, 0, SQLITE_UTF8,    0, 0          },
+    { "coalesce",           1, 0, SQLITE_UTF8,    0, 0          },
+    { "hex",                1, 0, SQLITE_UTF8,    0, hexFunc    },
+    { "ifnull",             2, 0, SQLITE_UTF8,    1, ifnullFunc },
+    { "random",            -1, 0, SQLITE_UTF8,    0, randomFunc },
+    { "randomblob",         1, 0, SQLITE_UTF8,    0, randomBlob },
+    { "nullif",             2, 0, SQLITE_UTF8,    1, nullifFunc },
+    { "sqlite_version",     0, 0, SQLITE_UTF8,    0, versionFunc},
+    { "quote",              1, 0, SQLITE_UTF8,    0, quoteFunc  },
+    { "last_insert_rowid",  0, 0, SQLITE_UTF8, 0, last_insert_rowid },
+    { "changes",            0, 0, SQLITE_UTF8, 0, changes           },
+    { "total_changes",      0, 0, SQLITE_UTF8, 0, total_changes     },
+    { "replace",            3, 0, SQLITE_UTF8,    0, replaceFunc       },
+    { "ltrim",              1, 1, SQLITE_UTF8,    0, trimFunc          },
+    { "ltrim",              2, 1, SQLITE_UTF8,    0, trimFunc          },
+    { "rtrim",              1, 2, SQLITE_UTF8,    0, trimFunc          },
+    { "rtrim",              2, 2, SQLITE_UTF8,    0, trimFunc          },
+    { "trim",               1, 3, SQLITE_UTF8,    0, trimFunc          },
+    { "trim",               2, 3, SQLITE_UTF8,    0, trimFunc          },
+    { "zeroblob",           1, 0, SQLITE_UTF8,    0, zeroblobFunc      },
+#ifdef SQLITE_SOUNDEX
+    { "soundex",            1, 0, SQLITE_UTF8,    0, soundexFunc},
+#endif
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+    { "load_extension",     1, 0, SQLITE_UTF8, 0, loadExt },
+    { "load_extension",     2, 0, SQLITE_UTF8, 0, loadExt },
+#endif
+  };
+  static const struct {
+    char *zName;
+    signed char nArg;
+    u8 argType;
+    u8 needCollSeq;
+    void (*xStep)(sqlite3_context*,int,sqlite3_value**);
+    void (*xFinalize)(sqlite3_context*);
+  } aAggs[] = {
+    { "min",    1, 0, 1, minmaxStep,   minMaxFinalize },
+    { "max",    1, 1, 1, minmaxStep,   minMaxFinalize },
+    { "sum",    1, 0, 0, sumStep,      sumFinalize    },
+    { "total",  1, 0, 0, sumStep,      totalFinalize    },
+    { "avg",    1, 0, 0, sumStep,      avgFinalize    },
+    { "count",  0, 0, 0, countStep,    countFinalize  },
+    { "count",  1, 0, 0, countStep,    countFinalize  },
+    { "group_concat", 1, 0, 0, groupConcatStep, groupConcatFinalize },
+    { "group_concat", 2, 0, 0, groupConcatStep, groupConcatFinalize },
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    void *pArg;
+    u8 argType = aFuncs[i].argType;
+    pArg = (void*)(int)argType;
+    sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
+        aFuncs[i].eTextRep, pArg, aFuncs[i].xFunc, 0, 0);
+    if( aFuncs[i].needCollSeq ){
+      FuncDef *pFunc = sqlite3FindFunction(db, aFuncs[i].zName, 
+          strlen(aFuncs[i].zName), aFuncs[i].nArg, aFuncs[i].eTextRep, 0);
+      if( pFunc && aFuncs[i].needCollSeq ){
+        pFunc->needCollSeq = 1;
+      }
+    }
+  }
+#ifndef SQLITE_OMIT_ALTERTABLE
+  sqlite3AlterFunctions(db);
+#endif
+#ifndef SQLITE_OMIT_PARSER
+  sqlite3AttachFunctions(db);
+#endif
+  for(i=0; i<sizeof(aAggs)/sizeof(aAggs[0]); i++){
+    void *pArg = (void*)(int)aAggs[i].argType;
+    sqlite3CreateFunc(db, aAggs[i].zName, aAggs[i].nArg, SQLITE_UTF8, 
+        pArg, 0, aAggs[i].xStep, aAggs[i].xFinalize);
+    if( aAggs[i].needCollSeq ){
+      FuncDef *pFunc = sqlite3FindFunction( db, aAggs[i].zName,
+          strlen(aAggs[i].zName), aAggs[i].nArg, SQLITE_UTF8, 0);
+      if( pFunc && aAggs[i].needCollSeq ){
+        pFunc->needCollSeq = 1;
+      }
+    }
+  }
+  sqlite3RegisterDateTimeFunctions(db);
+  if( !db->mallocFailed ){
+    int rc = sqlite3_overload_function(db, "MATCH", 2);
+    assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
+    if( rc==SQLITE_NOMEM ){
+      db->mallocFailed = 1;
+    }
+  }
+#ifdef SQLITE_SSE
+  (void)sqlite3SseFunctions(db);
+#endif
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+  sqlite3RegisterLikeFunctions(db, 1);
+#else
+  sqlite3RegisterLikeFunctions(db, 0);
+#endif
+}
+
+/*
+** Set the LIKEOPT flag on the 2-argument function with the given name.
+*/
+static void setLikeOptFlag(sqlite3 *db, const char *zName, int flagVal){
+  FuncDef *pDef;
+  pDef = sqlite3FindFunction(db, zName, strlen(zName), 2, SQLITE_UTF8, 0);
+  if( pDef ){
+    pDef->flags = flagVal;
+  }
+}
+
+/*
+** Register the built-in LIKE and GLOB functions.  The caseSensitive
+** parameter determines whether or not the LIKE operator is case
+** sensitive.  GLOB is always case sensitive.
+*/
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive){
+  struct compareInfo *pInfo;
+  if( caseSensitive ){
+    pInfo = (struct compareInfo*)&likeInfoAlt;
+  }else{
+    pInfo = (struct compareInfo*)&likeInfoNorm;
+  }
+  sqlite3CreateFunc(db, "like", 2, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
+  sqlite3CreateFunc(db, "like", 3, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
+  sqlite3CreateFunc(db, "glob", 2, SQLITE_UTF8, 
+      (struct compareInfo*)&globInfo, likeFunc, 0,0);
+  setLikeOptFlag(db, "glob", SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE);
+  setLikeOptFlag(db, "like", 
+      caseSensitive ? (SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE) : SQLITE_FUNC_LIKE);
+}
+
+/*
+** pExpr points to an expression which implements a function.  If
+** it is appropriate to apply the LIKE optimization to that function
+** then set aWc[0] through aWc[2] to the wildcard characters and
+** return TRUE.  If the function is not a LIKE-style function then
+** return FALSE.
+*/
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3 *db, Expr *pExpr, int *pIsNocase, char *aWc){
+  FuncDef *pDef;
+  if( pExpr->op!=TK_FUNCTION || !pExpr->pList ){
+    return 0;
+  }
+  if( pExpr->pList->nExpr!=2 ){
+    return 0;
+  }
+  pDef = sqlite3FindFunction(db, (char*)pExpr->token.z, pExpr->token.n, 2,
+                             SQLITE_UTF8, 0);
+  if( pDef==0 || (pDef->flags & SQLITE_FUNC_LIKE)==0 ){
+    return 0;
+  }
+
+  /* The memcpy() statement assumes that the wildcard characters are
+  ** the first three statements in the compareInfo structure.  The
+  ** asserts() that follow verify that assumption
+  */
+  memcpy(aWc, pDef->pUserData, 3);
+  assert( (char*)&likeInfoAlt == (char*)&likeInfoAlt.matchAll );
+  assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
+  assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
+  *pIsNocase = (pDef->flags & SQLITE_FUNC_CASE)==0;
+  return 1;
+}
+
+/************** End of func.c ************************************************/
+/************** Begin file insert.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle INSERT statements in SQLite.
+**
+** $Id: insert.c,v 1.238 2008/04/28 18:46:43 drh Exp $
+*/
+
+/*
+** Set P4 of the most recently inserted opcode to a column affinity
+** string for index pIdx. A column affinity string has one character
+** for each column in the table, according to the affinity of the column:
+**
+**  Character      Column affinity
+**  ------------------------------
+**  'a'            TEXT
+**  'b'            NONE
+**  'c'            NUMERIC
+**  'd'            INTEGER
+**  'e'            REAL
+**
+** An extra 'b' is appended to the end of the string to cover the
+** rowid that appears as the last column in every index.
+*/
+SQLITE_PRIVATE void sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
+  if( !pIdx->zColAff ){
+    /* The first time a column affinity string for a particular index is
+    ** required, it is allocated and populated here. It is then stored as
+    ** a member of the Index structure for subsequent use.
+    **
+    ** The column affinity string will eventually be deleted by
+    ** sqliteDeleteIndex() when the Index structure itself is cleaned
+    ** up.
+    */
+    int n;
+    Table *pTab = pIdx->pTable;
+    sqlite3 *db = sqlite3VdbeDb(v);
+    pIdx->zColAff = (char *)sqlite3DbMallocRaw(db, pIdx->nColumn+2);
+    if( !pIdx->zColAff ){
+      return;
+    }
+    for(n=0; n<pIdx->nColumn; n++){
+      pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
+    }
+    pIdx->zColAff[n++] = SQLITE_AFF_NONE;
+    pIdx->zColAff[n] = 0;
+  }
+ 
+  sqlite3VdbeChangeP4(v, -1, pIdx->zColAff, 0);
+}
+
+/*
+** Set P4 of the most recently inserted opcode to a column affinity
+** string for table pTab. A column affinity string has one character
+** for each column indexed by the index, according to the affinity of the
+** column:
+**
+**  Character      Column affinity
+**  ------------------------------
+**  'a'            TEXT
+**  'b'            NONE
+**  'c'            NUMERIC
+**  'd'            INTEGER
+**  'e'            REAL
+*/
+SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
+  /* The first time a column affinity string for a particular table
+  ** is required, it is allocated and populated here. It is then 
+  ** stored as a member of the Table structure for subsequent use.
+  **
+  ** The column affinity string will eventually be deleted by
+  ** sqlite3DeleteTable() when the Table structure itself is cleaned up.
+  */
+  if( !pTab->zColAff ){
+    char *zColAff;
+    int i;
+    sqlite3 *db = sqlite3VdbeDb(v);
+
+    zColAff = (char *)sqlite3DbMallocRaw(db, pTab->nCol+1);
+    if( !zColAff ){
+      return;
+    }
+
+    for(i=0; i<pTab->nCol; i++){
+      zColAff[i] = pTab->aCol[i].affinity;
+    }
+    zColAff[pTab->nCol] = '\0';
+
+    pTab->zColAff = zColAff;
+  }
+
+  sqlite3VdbeChangeP4(v, -1, pTab->zColAff, 0);
+}
+
+/*
+** Return non-zero if the table pTab in database iDb or any of its indices
+** have been opened at any point in the VDBE program beginning at location
+** iStartAddr throught the end of the program.  This is used to see if 
+** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can 
+** run without using temporary table for the results of the SELECT. 
+*/
+static int readsTable(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
+  int i;
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+  for(i=iStartAddr; i<iEnd; i++){
+    VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
+    assert( pOp!=0 );
+    if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
+      Index *pIndex;
+      int tnum = pOp->p2;
+      if( tnum==pTab->tnum ){
+        return 1;
+      }
+      for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+        if( tnum==pIndex->tnum ){
+          return 1;
+        }
+      }
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pTab->pVtab ){
+      assert( pOp->p4.pVtab!=0 );
+      assert( pOp->p4type==P4_VTAB );
+      return 1;
+    }
+#endif
+  }
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/*
+** Write out code to initialize the autoincrement logic.  This code
+** looks up the current autoincrement value in the sqlite_sequence
+** table and stores that value in a register.  Code generated by
+** autoIncStep() will keep that register holding the largest
+** rowid value.  Code generated by autoIncEnd() will write the new
+** largest value of the counter back into the sqlite_sequence table.
+**
+** This routine returns the index of the mem[] cell that contains
+** the maximum rowid counter.
+**
+** Three consecutive registers are allocated by this routine.  The
+** first two hold the name of the target table and the maximum rowid 
+** inserted into the target table, respectively.
+** The third holds the rowid in sqlite_sequence where we will
+** write back the revised maximum rowid.  This routine returns the
+** index of the second of these three registers.
+*/
+static int autoIncBegin(
+  Parse *pParse,      /* Parsing context */
+  int iDb,            /* Index of the database holding pTab */
+  Table *pTab         /* The table we are writing to */
+){
+  int memId = 0;      /* Register holding maximum rowid */
+  if( pTab->autoInc ){
+    Vdbe *v = pParse->pVdbe;
+    Db *pDb = &pParse->db->aDb[iDb];
+    int iCur = pParse->nTab;
+    int addr;               /* Address of the top of the loop */
+    assert( v );
+    pParse->nMem++;         /* Holds name of table */
+    memId = ++pParse->nMem;
+    pParse->nMem++;
+    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
+    addr = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, pTab->zName, 0);
+    sqlite3VdbeAddOp2(v, OP_Rewind, iCur, addr+8);
+    sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, memId);
+    sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
+    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, memId+1);
+    sqlite3VdbeAddOp3(v, OP_Column, iCur, 1, memId);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+8);
+    sqlite3VdbeAddOp2(v, OP_Next, iCur, addr+2);
+    sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
+  }
+  return memId;
+}
+
+/*
+** Update the maximum rowid for an autoincrement calculation.
+**
+** This routine should be called when the top of the stack holds a
+** new rowid that is about to be inserted.  If that new rowid is
+** larger than the maximum rowid in the memId memory cell, then the
+** memory cell is updated.  The stack is unchanged.
+*/
+static void autoIncStep(Parse *pParse, int memId, int regRowid){
+  if( memId>0 ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
+  }
+}
+
+/*
+** After doing one or more inserts, the maximum rowid is stored
+** in reg[memId].  Generate code to write this value back into the
+** the sqlite_sequence table.
+*/
+static void autoIncEnd(
+  Parse *pParse,     /* The parsing context */
+  int iDb,           /* Index of the database holding pTab */
+  Table *pTab,       /* Table we are inserting into */
+  int memId          /* Memory cell holding the maximum rowid */
+){
+  if( pTab->autoInc ){
+    int iCur = pParse->nTab;
+    Vdbe *v = pParse->pVdbe;
+    Db *pDb = &pParse->db->aDb[iDb];
+    int j1;
+    int iRec = ++pParse->nMem;    /* Memory cell used for record */
+
+    assert( v );
+    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
+    j1 = sqlite3VdbeAddOp1(v, OP_NotNull, memId+1);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iCur, memId+1);
+    sqlite3VdbeJumpHere(v, j1);
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, memId-1, 2, iRec);
+    sqlite3VdbeAddOp3(v, OP_Insert, iCur, iRec, memId+1);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+    sqlite3VdbeAddOp1(v, OP_Close, iCur);
+  }
+}
+#else
+/*
+** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
+** above are all no-ops
+*/
+# define autoIncBegin(A,B,C) (0)
+# define autoIncStep(A,B,C)
+# define autoIncEnd(A,B,C,D)
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+
+/* Forward declaration */
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+);
+
+/*
+** This routine is call to handle SQL of the following forms:
+**
+**    insert into TABLE (IDLIST) values(EXPRLIST)
+**    insert into TABLE (IDLIST) select
+**
+** The IDLIST following the table name is always optional.  If omitted,
+** then a list of all columns for the table is substituted.  The IDLIST
+** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
+**
+** The pList parameter holds EXPRLIST in the first form of the INSERT
+** statement above, and pSelect is NULL.  For the second form, pList is
+** NULL and pSelect is a pointer to the select statement used to generate
+** data for the insert.
+**
+** The code generated follows one of four templates.  For a simple
+** select with data coming from a VALUES clause, the code executes
+** once straight down through.  The template looks like this:
+**
+**         open write cursor to <table> and its indices
+**         puts VALUES clause expressions onto the stack
+**         write the resulting record into <table>
+**         cleanup
+**
+** The three remaining templates assume the statement is of the form
+**
+**   INSERT INTO <table> SELECT ...
+**
+** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
+** in other words if the SELECT pulls all columns from a single table
+** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
+** if <table2> and <table1> are distinct tables but have identical
+** schemas, including all the same indices, then a special optimization
+** is invoked that copies raw records from <table2> over to <table1>.
+** See the xferOptimization() function for the implementation of this
+** template.  This is the second template.
+**
+**         open a write cursor to <table>
+**         open read cursor on <table2>
+**         transfer all records in <table2> over to <table>
+**         close cursors
+**         foreach index on <table>
+**           open a write cursor on the <table> index
+**           open a read cursor on the corresponding <table2> index
+**           transfer all records from the read to the write cursors
+**           close cursors
+**         end foreach
+**
+** The third template is for when the second template does not apply
+** and the SELECT clause does not read from <table> at any time.
+** The generated code follows this template:
+**
+**         goto B
+**      A: setup for the SELECT
+**         loop over the rows in the SELECT
+**           gosub C
+**         end loop
+**         cleanup after the SELECT
+**         goto D
+**      B: open write cursor to <table> and its indices
+**         goto A
+**      C: insert the select result into <table>
+**         return
+**      D: cleanup
+**
+** The fourth template is used if the insert statement takes its
+** values from a SELECT but the data is being inserted into a table
+** that is also read as part of the SELECT.  In the third form,
+** we have to use a intermediate table to store the results of
+** the select.  The template is like this:
+**
+**         goto B
+**      A: setup for the SELECT
+**         loop over the tables in the SELECT
+**           gosub C
+**         end loop
+**         cleanup after the SELECT
+**         goto D
+**      C: insert the select result into the intermediate table
+**         return
+**      B: open a cursor to an intermediate table
+**         goto A
+**      D: open write cursor to <table> and its indices
+**         loop over the intermediate table
+**           transfer values form intermediate table into <table>
+**         end the loop
+**         cleanup
+*/
+SQLITE_PRIVATE void sqlite3Insert(
+  Parse *pParse,        /* Parser context */
+  SrcList *pTabList,    /* Name of table into which we are inserting */
+  ExprList *pList,      /* List of values to be inserted */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  IdList *pColumn,      /* Column names corresponding to IDLIST. */
+  int onError           /* How to handle constraint errors */
+){
+  sqlite3 *db;          /* The main database structure */
+  Table *pTab;          /* The table to insert into.  aka TABLE */
+  char *zTab;           /* Name of the table into which we are inserting */
+  const char *zDb;      /* Name of the database holding this table */
+  int i, j, idx;        /* Loop counters */
+  Vdbe *v;              /* Generate code into this virtual machine */
+  Index *pIdx;          /* For looping over indices of the table */
+  int nColumn;          /* Number of columns in the data */
+  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
+  int baseCur = 0;      /* VDBE Cursor number for pTab */
+  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
+  int endOfLoop;        /* Label for the end of the insertion loop */
+  int useTempTable = 0; /* Store SELECT results in intermediate table */
+  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
+  int iCont=0,iBreak=0; /* Beginning and end of the loop over srcTab */
+  int iSelectLoop = 0;  /* Address of code that implements the SELECT */
+  int iCleanup = 0;     /* Address of the cleanup code */
+  int iInsertBlock = 0; /* Address of the subroutine used to insert data */
+  int newIdx = -1;      /* Cursor for the NEW pseudo-table */
+  int iDb;              /* Index of database holding TABLE */
+  Db *pDb;              /* The database containing table being inserted into */
+  int appendFlag = 0;   /* True if the insert is likely to be an append */
+
+  /* Register allocations */
+  int regFromSelect;    /* Base register for data coming from SELECT */
+  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
+  int regRowCount = 0;  /* Memory cell used for the row counter */
+  int regIns;           /* Block of regs holding rowid+data being inserted */
+  int regRowid;         /* registers holding insert rowid */
+  int regData;          /* register holding first column to insert */
+  int regRecord;        /* Holds the assemblied row record */
+  int *aRegIdx = 0;     /* One register allocated to each index */
+
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                 /* True if attempting to insert into a view */
+  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
+#endif
+
+  db = pParse->db;
+  if( pParse->nErr || db->mallocFailed ){
+    goto insert_cleanup;
+  }
+
+  /* Locate the table into which we will be inserting new information.
+  */
+  assert( pTabList->nSrc==1 );
+  zTab = pTabList->a[0].zName;
+  if( zTab==0 ) goto insert_cleanup;
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ){
+    goto insert_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  pDb = &db->aDb[iDb];
+  zDb = pDb->zName;
+  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
+    goto insert_cleanup;
+  }
+
+  /* Figure out if we have any triggers and if the table being
+  ** inserted into is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0);
+  isView = pTab->pSelect!=0;
+#else
+# define triggers_exist 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+  /* Ensure that:
+  *  (a) the table is not read-only, 
+  *  (b) that if it is a view then ON INSERT triggers exist
+  */
+  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+    goto insert_cleanup;
+  }
+  assert( pTab!=0 );
+
+  /* If pTab is really a view, make sure it has been initialized.
+  ** ViewGetColumnNames() is a no-op if pTab is not a view (or virtual 
+  ** module table).
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto insert_cleanup;
+  }
+
+  /* Allocate a VDBE
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto insert_cleanup;
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, pSelect || triggers_exist, iDb);
+
+  /* if there are row triggers, allocate a temp table for new.* references. */
+  if( triggers_exist ){
+    newIdx = pParse->nTab++;
+  }
+
+#ifndef SQLITE_OMIT_XFER_OPT
+  /* If the statement is of the form
+  **
+  **       INSERT INTO <table1> SELECT * FROM <table2>;
+  **
+  ** Then special optimizations can be applied that make the transfer
+  ** very fast and which reduce fragmentation of indices.
+  */
+  if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
+    assert( !triggers_exist );
+    assert( pList==0 );
+    goto insert_cleanup;
+  }
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+  /* If this is an AUTOINCREMENT table, look up the sequence number in the
+  ** sqlite_sequence table and store it in memory cell regAutoinc.
+  */
+  regAutoinc = autoIncBegin(pParse, iDb, pTab);
+
+  /* Figure out how many columns of data are supplied.  If the data
+  ** is coming from a SELECT statement, then this step also generates
+  ** all the code to implement the SELECT statement and invoke a subroutine
+  ** to process each row of the result. (Template 2.) If the SELECT
+  ** statement uses the the table that is being inserted into, then the
+  ** subroutine is also coded here.  That subroutine stores the SELECT
+  ** results in a temporary table. (Template 3.)
+  */
+  if( pSelect ){
+    /* Data is coming from a SELECT.  Generate code to implement that SELECT
+    */
+    SelectDest dest;
+    int rc, iInitCode;
+
+    iInitCode = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
+    iSelectLoop = sqlite3VdbeCurrentAddr(v);
+    iInsertBlock = sqlite3VdbeMakeLabel(v);
+    sqlite3SelectDestInit(&dest, SRT_Subroutine, iInsertBlock);
+
+    /* Resolve the expressions in the SELECT statement and execute it. */
+    rc = sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);
+    if( rc || pParse->nErr || db->mallocFailed ){
+      goto insert_cleanup;
+    }
+
+    regFromSelect = dest.iMem;
+    iCleanup = sqlite3VdbeMakeLabel(v);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, iCleanup);
+    assert( pSelect->pEList );
+    nColumn = pSelect->pEList->nExpr;
+
+    /* Set useTempTable to TRUE if the result of the SELECT statement
+    ** should be written into a temporary table.  Set to FALSE if each
+    ** row of the SELECT can be written directly into the result table.
+    **
+    ** A temp table must be used if the table being updated is also one
+    ** of the tables being read by the SELECT statement.  Also use a 
+    ** temp table in the case of row triggers.
+    */
+    if( triggers_exist || readsTable(v, iSelectLoop, iDb, pTab) ){
+      useTempTable = 1;
+    }
+
+    if( useTempTable ){
+      /* Generate the subroutine that SELECT calls to process each row of
+      ** the result.  Store the result in a temporary table
+      */
+      int regRec, regRowid;
+
+      srcTab = pParse->nTab++;
+      regRec = sqlite3GetTempReg(pParse);
+      regRowid = sqlite3GetTempReg(pParse);
+      sqlite3VdbeResolveLabel(v, iInsertBlock);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regRowid);
+      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+      sqlite3ReleaseTempReg(pParse, regRec);
+      sqlite3ReleaseTempReg(pParse, regRowid);
+
+      /* The following code runs first because the GOTO at the very top
+      ** of the program jumps to it.  Create the temporary table, then jump
+      ** back up and execute the SELECT code above.
+      */
+      sqlite3VdbeJumpHere(v, iInitCode);
+      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iSelectLoop);
+      sqlite3VdbeResolveLabel(v, iCleanup);
+    }else{
+      sqlite3VdbeJumpHere(v, iInitCode);
+    }
+  }else{
+    /* This is the case if the data for the INSERT is coming from a VALUES
+    ** clause
+    */
+    NameContext sNC;
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    srcTab = -1;
+    assert( useTempTable==0 );
+    nColumn = pList ? pList->nExpr : 0;
+    for(i=0; i<nColumn; i++){
+      if( sqlite3ExprResolveNames(&sNC, pList->a[i].pExpr) ){
+        goto insert_cleanup;
+      }
+    }
+  }
+
+  /* Make sure the number of columns in the source data matches the number
+  ** of columns to be inserted into the table.
+  */
+  if( IsVirtual(pTab) ){
+    for(i=0; i<pTab->nCol; i++){
+      nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
+    }
+  }
+  if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
+    sqlite3ErrorMsg(pParse, 
+       "table %S has %d columns but %d values were supplied",
+       pTabList, 0, pTab->nCol, nColumn);
+    goto insert_cleanup;
+  }
+  if( pColumn!=0 && nColumn!=pColumn->nId ){
+    sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
+    goto insert_cleanup;
+  }
+
+  /* If the INSERT statement included an IDLIST term, then make sure
+  ** all elements of the IDLIST really are columns of the table and 
+  ** remember the column indices.
+  **
+  ** If the table has an INTEGER PRIMARY KEY column and that column
+  ** is named in the IDLIST, then record in the keyColumn variable
+  ** the index into IDLIST of the primary key column.  keyColumn is
+  ** the index of the primary key as it appears in IDLIST, not as
+  ** is appears in the original table.  (The index of the primary
+  ** key in the original table is pTab->iPKey.)
+  */
+  if( pColumn ){
+    for(i=0; i<pColumn->nId; i++){
+      pColumn->a[i].idx = -1;
+    }
+    for(i=0; i<pColumn->nId; i++){
+      for(j=0; j<pTab->nCol; j++){
+        if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
+          pColumn->a[i].idx = j;
+          if( j==pTab->iPKey ){
+            keyColumn = i;
+          }
+          break;
+        }
+      }
+      if( j>=pTab->nCol ){
+        if( sqlite3IsRowid(pColumn->a[i].zName) ){
+          keyColumn = i;
+        }else{
+          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
+              pTabList, 0, pColumn->a[i].zName);
+          pParse->nErr++;
+          goto insert_cleanup;
+        }
+      }
+    }
+  }
+
+  /* If there is no IDLIST term but the table has an integer primary
+  ** key, the set the keyColumn variable to the primary key column index
+  ** in the original table definition.
+  */
+  if( pColumn==0 && nColumn>0 ){
+    keyColumn = pTab->iPKey;
+  }
+
+  /* Open the temp table for FOR EACH ROW triggers
+  */
+  if( triggers_exist ){
+    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
+    sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
+  }
+    
+  /* Initialize the count of rows to be inserted
+  */
+  if( db->flags & SQLITE_CountRows ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  /* If this is not a view, open the table and and all indices */
+  if( !isView ){
+    int nIdx;
+    int i;
+
+    baseCur = pParse->nTab;
+    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, baseCur, OP_OpenWrite);
+    aRegIdx = sqlite3DbMallocRaw(db, sizeof(int)*(nIdx+1));
+    if( aRegIdx==0 ){
+      goto insert_cleanup;
+    }
+    for(i=0; i<nIdx; i++){
+      aRegIdx[i] = ++pParse->nMem;
+    }
+  }
+
+  /* If the data source is a temporary table, then we have to create
+  ** a loop because there might be multiple rows of data.  If the data
+  ** source is a subroutine call from the SELECT statement, then we need
+  ** to launch the SELECT statement processing.
+  */
+  if( useTempTable ){
+    iBreak = sqlite3VdbeMakeLabel(v);
+    sqlite3VdbeAddOp2(v, OP_Rewind, srcTab, iBreak);
+    iCont = sqlite3VdbeCurrentAddr(v);
+  }else if( pSelect ){
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, iSelectLoop);
+    sqlite3VdbeResolveLabel(v, iInsertBlock);
+  }
+
+  /* Allocate registers for holding the rowid of the new row,
+  ** the content of the new row, and the assemblied row record.
+  */
+  regRecord = ++pParse->nMem;
+  regRowid = regIns = pParse->nMem+1;
+  pParse->nMem += pTab->nCol + 1;
+  if( IsVirtual(pTab) ){
+    regRowid++;
+    pParse->nMem++;
+  }
+  regData = regRowid+1;
+
+  /* Run the BEFORE and INSTEAD OF triggers, if there are any
+  */
+  endOfLoop = sqlite3VdbeMakeLabel(v);
+  if( triggers_exist & TRIGGER_BEFORE ){
+    int regRowid;
+    int regCols;
+    int regRec;
+
+    /* build the NEW.* reference row.  Note that if there is an INTEGER
+    ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
+    ** translated into a unique ID for the row.  But on a BEFORE trigger,
+    ** we do not know what the unique ID will be (because the insert has
+    ** not happened yet) so we substitute a rowid of -1
+    */
+    regRowid = sqlite3GetTempReg(pParse);
+    if( keyColumn<0 ){
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regRowid);
+    }else if( useTempTable ){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regRowid);
+    }else{
+      int j1;
+      assert( pSelect==0 );  /* Otherwise useTempTable is true */
+      sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regRowid);
+      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regRowid);
+      sqlite3VdbeJumpHere(v, j1);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
+    }
+
+    /* Cannot have triggers on a virtual table. If it were possible,
+    ** this block would have to account for hidden column.
+    */
+    assert(!IsVirtual(pTab));
+
+    /* Create the new column data
+    */
+    regCols = sqlite3GetTempRange(pParse, pTab->nCol);
+    for(i=0; i<pTab->nCol; i++){
+      if( pColumn==0 ){
+        j = i;
+      }else{
+        for(j=0; j<pColumn->nId; j++){
+          if( pColumn->a[j].idx==i ) break;
+        }
+      }
+      if( pColumn && j>=pColumn->nId ){
+        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i);
+      }else if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i); 
+      }else{
+        assert( pSelect==0 ); /* Otherwise useTempTable is true */
+        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i);
+      }
+    }
+    regRec = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRec);
+
+    /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
+    ** do not attempt any conversions before assembling the record.
+    ** If this is a real table, attempt conversions as required by the
+    ** table column affinities.
+    */
+    if( !isView ){
+      sqlite3TableAffinityStr(v, pTab);
+    }
+    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRec, regRowid);
+    sqlite3ReleaseTempReg(pParse, regRec);
+    sqlite3ReleaseTempReg(pParse, regRowid);
+    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
+
+    /* Fire BEFORE or INSTEAD OF triggers */
+    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_BEFORE, pTab, 
+        newIdx, -1, onError, endOfLoop, 0, 0) ){
+      goto insert_cleanup;
+    }
+  }
+
+  /* Push the record number for the new entry onto the stack.  The
+  ** record number is a randomly generate integer created by NewRowid
+  ** except when the table has an INTEGER PRIMARY KEY column, in which
+  ** case the record number is the same as that column. 
+  */
+  if( !isView ){
+    if( IsVirtual(pTab) ){
+      /* The row that the VUpdate opcode will delete: none */
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
+    }
+    if( keyColumn>=0 ){
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regRowid);
+      }else if( pSelect ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+keyColumn, regRowid);
+      }else{
+        VdbeOp *pOp;
+        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regRowid);
+        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
+        if( pOp && pOp->opcode==OP_Null ){
+          appendFlag = 1;
+          pOp->opcode = OP_NewRowid;
+          pOp->p1 = baseCur;
+          pOp->p2 = regRowid;
+          pOp->p3 = regAutoinc;
+        }
+      }
+      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
+      ** to generate a unique primary key value.
+      */
+      if( !appendFlag ){
+        int j1;
+        j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid);
+        sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
+        sqlite3VdbeJumpHere(v, j1);
+        sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
+      }
+    }else if( IsVirtual(pTab) ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
+      appendFlag = 1;
+    }
+    autoIncStep(pParse, regAutoinc, regRowid);
+
+    /* Push onto the stack, data for all columns of the new entry, beginning
+    ** with the first column.
+    */
+    nHidden = 0;
+    for(i=0; i<pTab->nCol; i++){
+      int iRegStore = regRowid+1+i;
+      if( i==pTab->iPKey ){
+        /* The value of the INTEGER PRIMARY KEY column is always a NULL.
+        ** Whenever this column is read, the record number will be substituted
+        ** in its place.  So will fill this column with a NULL to avoid
+        ** taking up data space with information that will never be used. */
+        sqlite3VdbeAddOp2(v, OP_Null, 0, iRegStore);
+        continue;
+      }
+      if( pColumn==0 ){
+        if( IsHiddenColumn(&pTab->aCol[i]) ){
+          assert( IsVirtual(pTab) );
+          j = -1;
+          nHidden++;
+        }else{
+          j = i - nHidden;
+        }
+      }else{
+        for(j=0; j<pColumn->nId; j++){
+          if( pColumn->a[j].idx==i ) break;
+        }
+      }
+      if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
+        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, iRegStore);
+      }else if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore); 
+      }else if( pSelect ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
+      }else{
+        sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
+      }
+    }
+
+    /* Generate code to check constraints and generate index keys and
+    ** do the insertion.
+    */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      sqlite3VtabMakeWritable(pParse, pTab);
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns,
+                     (const char*)pTab->pVtab, P4_VTAB);
+    }else
+#endif
+    {
+      sqlite3GenerateConstraintChecks(
+          pParse,
+          pTab,
+          baseCur,
+          regIns,
+          aRegIdx,
+          keyColumn>=0,
+          0,
+          onError,
+          endOfLoop
+      );
+      sqlite3CompleteInsertion(
+          pParse,
+          pTab,
+          baseCur,
+          regIns,
+          aRegIdx,
+          0,
+          0,
+          (triggers_exist & TRIGGER_AFTER)!=0 ? newIdx : -1,
+          appendFlag
+       );
+    }
+  }
+
+  /* Update the count of rows that are inserted
+  */
+  if( (db->flags & SQLITE_CountRows)!=0 ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  if( triggers_exist ){
+    /* Code AFTER triggers */
+    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_AFTER, pTab,
+          newIdx, -1, onError, endOfLoop, 0, 0) ){
+      goto insert_cleanup;
+    }
+  }
+
+  /* The bottom of the loop, if the data source is a SELECT statement
+  */
+  sqlite3VdbeResolveLabel(v, endOfLoop);
+  if( useTempTable ){
+    sqlite3VdbeAddOp2(v, OP_Next, srcTab, iCont);
+    sqlite3VdbeResolveLabel(v, iBreak);
+    sqlite3VdbeAddOp2(v, OP_Close, srcTab, 0);
+  }else if( pSelect ){
+    sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+    sqlite3VdbeResolveLabel(v, iCleanup);
+  }
+
+  if( !IsVirtual(pTab) && !isView ){
+    /* Close all tables opened */
+    sqlite3VdbeAddOp2(v, OP_Close, baseCur, 0);
+    for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
+      sqlite3VdbeAddOp2(v, OP_Close, idx+baseCur, 0);
+    }
+  }
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** counter value in memory regAutoinc back into the sqlite_sequence
+  ** table.
+  */
+  autoIncEnd(pParse, iDb, pTab, regAutoinc);
+
+  /*
+  ** Return the number of rows inserted. If this routine is 
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
+    sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", P4_STATIC);
+  }
+
+insert_cleanup:
+  sqlite3SrcListDelete(pTabList);
+  sqlite3ExprListDelete(pList);
+  sqlite3SelectDelete(pSelect);
+  sqlite3IdListDelete(pColumn);
+  sqlite3_free(aRegIdx);
+}
+
+/*
+** Generate code to do constraint checks prior to an INSERT or an UPDATE.
+**
+** The input is a range of consecutive registers as follows:
+**
+**    1.  The rowid of the row to be updated before the update.  This
+**        value is omitted unless we are doing an UPDATE that involves a
+**        change to the record number or writing to a virtual table.
+**
+**    2.  The rowid of the row after the update.
+**
+**    3.  The data in the first column of the entry after the update.
+**
+**    i.  Data from middle columns...
+**
+**    N.  The data in the last column of the entry after the update.
+**
+** The regRowid parameter is the index of the register containing (2).
+**
+** The old rowid shown as entry (1) above is omitted unless both isUpdate
+** and rowidChng are 1.  isUpdate is true for UPDATEs and false for
+** INSERTs.  RowidChng means that the new rowid is explicitly specified by
+** the update or insert statement.  If rowidChng is false, it means that
+** the rowid is computed automatically in an insert or that the rowid value
+** is not modified by the update.
+**
+** The code generated by this routine store new index entries into
+** registers identified by aRegIdx[].  No index entry is created for
+** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
+** the same as the order of indices on the linked list of indices
+** attached to the table.
+**
+** This routine also generates code to check constraints.  NOT NULL,
+** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
+** then the appropriate action is performed.  There are five possible
+** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
+**
+**  Constraint type  Action       What Happens
+**  ---------------  ----------   ----------------------------------------
+**  any              ROLLBACK     The current transaction is rolled back and
+**                                sqlite3_exec() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.
+**
+**  any              ABORT        Back out changes from the current command
+**                                only (do not do a complete rollback) then
+**                                cause sqlite3_exec() to return immediately
+**                                with SQLITE_CONSTRAINT.
+**
+**  any              FAIL         Sqlite_exec() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.  The
+**                                transaction is not rolled back and any
+**                                prior changes are retained.
+**
+**  any              IGNORE       The record number and data is popped from
+**                                the stack and there is an immediate jump
+**                                to label ignoreDest.
+**
+**  NOT NULL         REPLACE      The NULL value is replace by the default
+**                                value for that column.  If the default value
+**                                is NULL, the action is the same as ABORT.
+**
+**  UNIQUE           REPLACE      The other row that conflicts with the row
+**                                being inserted is removed.
+**
+**  CHECK            REPLACE      Illegal.  The results in an exception.
+**
+** Which action to take is determined by the overrideError parameter.
+** Or if overrideError==OE_Default, then the pParse->onError parameter
+** is used.  Or if pParse->onError==OE_Default then the onError value
+** for the constraint is used.
+**
+** The calling routine must open a read/write cursor for pTab with
+** cursor number "baseCur".  All indices of pTab must also have open
+** read/write cursors with cursor number baseCur+i for the i-th cursor.
+** Except, if there is no possibility of a REPLACE action then
+** cursors do not need to be open for indices where aRegIdx[i]==0.
+*/
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
+  Parse *pParse,      /* The parser context */
+  Table *pTab,        /* the table into which we are inserting */
+  int baseCur,        /* Index of a read/write cursor pointing at pTab */
+  int regRowid,       /* Index of the range of input registers */
+  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
+  int rowidChng,      /* True if the rowid might collide with existing entry */
+  int isUpdate,       /* True for UPDATE, False for INSERT */
+  int overrideError,  /* Override onError to this if not OE_Default */
+  int ignoreDest      /* Jump to this label on an OE_Ignore resolution */
+){
+  int i;
+  Vdbe *v;
+  int nCol;
+  int onError;
+  int j1, j2, j3;     /* Addresses of jump instructions */
+  int regData;        /* Register containing first data column */
+  int iCur;
+  Index *pIdx;
+  int seenReplace = 0;
+  int hasTwoRowids = (isUpdate && rowidChng);
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
+  nCol = pTab->nCol;
+  regData = regRowid + 1;
+
+
+  /* Test all NOT NULL constraints.
+  */
+  for(i=0; i<nCol; i++){
+    if( i==pTab->iPKey ){
+      continue;
+    }
+    onError = pTab->aCol[i].notNull;
+    if( onError==OE_None ) continue;
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+    if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
+      onError = OE_Abort;
+    }
+    j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regData+i);
+    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+        || onError==OE_Ignore || onError==OE_Replace );
+    switch( onError ){
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        char *zMsg = 0;
+        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
+        sqlite3SetString(&zMsg, pTab->zName, ".", pTab->aCol[i].zName,
+                        " may not be NULL", (char*)0);
+        sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
+        break;
+      }
+      case OE_Ignore: {
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+        break;
+      }
+      case OE_Replace: {
+        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regData+i);
+        break;
+      }
+    }
+    sqlite3VdbeJumpHere(v, j1);
+  }
+
+  /* Test all CHECK constraints
+  */
+#ifndef SQLITE_OMIT_CHECK
+  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
+    int allOk = sqlite3VdbeMakeLabel(v);
+    pParse->ckBase = regData;
+    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, SQLITE_JUMPIFNULL);
+    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
+    if( onError==OE_Ignore ){
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
+    }
+    sqlite3VdbeResolveLabel(v, allOk);
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+
+  /* If we have an INTEGER PRIMARY KEY, make sure the primary key
+  ** of the new record does not previously exist.  Except, if this
+  ** is an UPDATE and the primary key is not changing, that is OK.
+  */
+  if( rowidChng ){
+    onError = pTab->keyConf;
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+    
+    if( onError!=OE_Replace || pTab->pIndex ){
+      if( isUpdate ){
+        j2 = sqlite3VdbeAddOp3(v, OP_Eq, regRowid, 0, regRowid-1);
+      }
+      j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
+      switch( onError ){
+        default: {
+          onError = OE_Abort;
+          /* Fall thru into the next case */
+        }
+        case OE_Rollback:
+        case OE_Abort:
+        case OE_Fail: {
+          sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
+                           "PRIMARY KEY must be unique", P4_STATIC);
+          break;
+        }
+        case OE_Replace: {
+          sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
+          seenReplace = 1;
+          break;
+        }
+        case OE_Ignore: {
+          assert( seenReplace==0 );
+          sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+          break;
+        }
+      }
+      sqlite3VdbeJumpHere(v, j3);
+      if( isUpdate ){
+        sqlite3VdbeJumpHere(v, j2);
+      }
+    }
+  }
+
+  /* Test all UNIQUE constraints by creating entries for each UNIQUE
+  ** index and making sure that duplicate entries do not already exist.
+  ** Add the new records to the indices as we go.
+  */
+  for(iCur=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, iCur++){
+    int regIdx;
+    int regR;
+
+    if( aRegIdx[iCur]==0 ) continue;  /* Skip unused indices */
+
+    /* Create a key for accessing the index entry */
+    regIdx = sqlite3GetTempRange(pParse, pIdx->nColumn+1);
+    for(i=0; i<pIdx->nColumn; i++){
+      int idx = pIdx->aiColumn[i];
+      if( idx==pTab->iPKey ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_SCopy, regData+idx, regIdx+i);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn+1, aRegIdx[iCur]);
+    sqlite3IndexAffinityStr(v, pIdx);
+    sqlite3ExprCacheAffinityChange(pParse, regIdx, pIdx->nColumn+1);
+    sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
+
+    /* Find out what action to take in case there is an indexing conflict */
+    onError = pIdx->onError;
+    if( onError==OE_None ) continue;  /* pIdx is not a UNIQUE index */
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+    if( seenReplace ){
+      if( onError==OE_Ignore ) onError = OE_Replace;
+      else if( onError==OE_Fail ) onError = OE_Abort;
+    }
+    
+
+    /* Check to see if the new index entry will be unique */
+    j2 = sqlite3VdbeAddOp3(v, OP_IsNull, regIdx, 0, pIdx->nColumn);
+    regR = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp2(v, OP_SCopy, regRowid-hasTwoRowids, regR);
+    j3 = sqlite3VdbeAddOp4(v, OP_IsUnique, baseCur+iCur+1, 0,
+                           regR, (char*)aRegIdx[iCur],
+                           P4_INT32);
+
+    /* Generate code that executes if the new index entry is not unique */
+    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+        || onError==OE_Ignore || onError==OE_Replace );
+    switch( onError ){
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        int j, n1, n2;
+        char zErrMsg[200];
+        sqlite3_snprintf(sizeof(zErrMsg), zErrMsg,
+                         pIdx->nColumn>1 ? "columns " : "column ");
+        n1 = strlen(zErrMsg);
+        for(j=0; j<pIdx->nColumn && n1<sizeof(zErrMsg)-30; j++){
+          char *zCol = pTab->aCol[pIdx->aiColumn[j]].zName;
+          n2 = strlen(zCol);
+          if( j>0 ){
+            sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], ", ");
+            n1 += 2;
+          }
+          if( n1+n2>sizeof(zErrMsg)-30 ){
+            sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], "...");
+            n1 += 3;
+            break;
+          }else{
+            sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], "%s", zCol);
+            n1 += n2;
+          }
+        }
+        sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], 
+            pIdx->nColumn>1 ? " are not unique" : " is not unique");
+        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0, zErrMsg,0);
+        break;
+      }
+      case OE_Ignore: {
+        assert( seenReplace==0 );
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+        break;
+      }
+      case OE_Replace: {
+        sqlite3GenerateRowDelete(pParse, pTab, baseCur, regR, 0);
+        seenReplace = 1;
+        break;
+      }
+    }
+    sqlite3VdbeJumpHere(v, j2);
+    sqlite3VdbeJumpHere(v, j3);
+    sqlite3ReleaseTempReg(pParse, regR);
+  }
+}
+
+/*
+** This routine generates code to finish the INSERT or UPDATE operation
+** that was started by a prior call to sqlite3GenerateConstraintChecks.
+** A consecutive range of registers starting at regRowid contains the
+** rowid and the content to be inserted.
+**
+** The arguments to this routine should be the same as the first six
+** arguments to sqlite3GenerateConstraintChecks.
+*/
+SQLITE_PRIVATE void sqlite3CompleteInsertion(
+  Parse *pParse,      /* The parser context */
+  Table *pTab,        /* the table into which we are inserting */
+  int baseCur,        /* Index of a read/write cursor pointing at pTab */
+  int regRowid,       /* Range of content */
+  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
+  int rowidChng,      /* True if the record number will change */
+  int isUpdate,       /* True for UPDATE, False for INSERT */
+  int newIdx,         /* Index of NEW table for triggers.  -1 if none */
+  int appendBias      /* True if this is likely to be an append */
+){
+  int i;
+  Vdbe *v;
+  int nIdx;
+  Index *pIdx;
+  int pik_flags;
+  int regData;
+  int regRec;
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
+  for(i=nIdx-1; i>=0; i--){
+    if( aRegIdx[i]==0 ) continue;
+    sqlite3VdbeAddOp2(v, OP_IdxInsert, baseCur+i+1, aRegIdx[i]);
+  }
+  regData = regRowid + 1;
+  regRec = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
+  sqlite3TableAffinityStr(v, pTab);
+  sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
+#ifndef SQLITE_OMIT_TRIGGER
+  if( newIdx>=0 ){
+    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRec, regRowid);
+  }
+#endif
+  if( pParse->nested ){
+    pik_flags = 0;
+  }else{
+    pik_flags = OPFLAG_NCHANGE;
+    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
+  }
+  if( appendBias ){
+    pik_flags |= OPFLAG_APPEND;
+  }
+  sqlite3VdbeAddOp3(v, OP_Insert, baseCur, regRec, regRowid);
+  if( !pParse->nested ){
+    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+  }
+  sqlite3VdbeChangeP5(v, pik_flags);
+}
+
+/*
+** Generate code that will open cursors for a table and for all
+** indices of that table.  The "baseCur" parameter is the cursor number used
+** for the table.  Indices are opened on subsequent cursors.
+**
+** Return the number of indices on the table.
+*/
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(
+  Parse *pParse,   /* Parsing context */
+  Table *pTab,     /* Table to be opened */
+  int baseCur,        /* Cursor number assigned to the table */
+  int op           /* OP_OpenRead or OP_OpenWrite */
+){
+  int i;
+  int iDb;
+  Index *pIdx;
+  Vdbe *v;
+
+  if( IsVirtual(pTab) ) return 0;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  sqlite3OpenTable(pParse, baseCur, iDb, pTab, op);
+  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
+    assert( pIdx->pSchema==pTab->pSchema );
+    sqlite3VdbeAddOp4(v, op, i+baseCur, pIdx->tnum, iDb,
+                      (char*)pKey, P4_KEYINFO_HANDOFF);
+    VdbeComment((v, "%s", pIdx->zName));
+  }
+  if( pParse->nTab<=baseCur+i ){
+    pParse->nTab = baseCur+i;
+  }
+  return i-1;
+}
+
+
+#ifdef SQLITE_TEST
+/*
+** The following global variable is incremented whenever the
+** transfer optimization is used.  This is used for testing
+** purposes only - to make sure the transfer optimization really
+** is happening when it is suppose to.
+*/
+SQLITE_API int sqlite3_xferopt_count;
+#endif /* SQLITE_TEST */
+
+
+#ifndef SQLITE_OMIT_XFER_OPT
+/*
+** Check to collation names to see if they are compatible.
+*/
+static int xferCompatibleCollation(const char *z1, const char *z2){
+  if( z1==0 ){
+    return z2==0;
+  }
+  if( z2==0 ){
+    return 0;
+  }
+  return sqlite3StrICmp(z1, z2)==0;
+}
+
+
+/*
+** Check to see if index pSrc is compatible as a source of data
+** for index pDest in an insert transfer optimization.  The rules
+** for a compatible index:
+**
+**    *   The index is over the same set of columns
+**    *   The same DESC and ASC markings occurs on all columns
+**    *   The same onError processing (OE_Abort, OE_Ignore, etc)
+**    *   The same collating sequence on each column
+*/
+static int xferCompatibleIndex(Index *pDest, Index *pSrc){
+  int i;
+  assert( pDest && pSrc );
+  assert( pDest->pTable!=pSrc->pTable );
+  if( pDest->nColumn!=pSrc->nColumn ){
+    return 0;   /* Different number of columns */
+  }
+  if( pDest->onError!=pSrc->onError ){
+    return 0;   /* Different conflict resolution strategies */
+  }
+  for(i=0; i<pSrc->nColumn; i++){
+    if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
+      return 0;   /* Different columns indexed */
+    }
+    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
+      return 0;   /* Different sort orders */
+    }
+    if( pSrc->azColl[i]!=pDest->azColl[i] ){
+      return 0;   /* Different collating sequences */
+    }
+  }
+
+  /* If no test above fails then the indices must be compatible */
+  return 1;
+}
+
+/*
+** Attempt the transfer optimization on INSERTs of the form
+**
+**     INSERT INTO tab1 SELECT * FROM tab2;
+**
+** This optimization is only attempted if
+**
+**    (1)  tab1 and tab2 have identical schemas including all the
+**         same indices and constraints
+**
+**    (2)  tab1 and tab2 are different tables
+**
+**    (3)  There must be no triggers on tab1
+**
+**    (4)  The result set of the SELECT statement is "*"
+**
+**    (5)  The SELECT statement has no WHERE, HAVING, ORDER BY, GROUP BY,
+**         or LIMIT clause.
+**
+**    (6)  The SELECT statement is a simple (not a compound) select that
+**         contains only tab2 in its FROM clause
+**
+** This method for implementing the INSERT transfers raw records from
+** tab2 over to tab1.  The columns are not decoded.  Raw records from
+** the indices of tab2 are transfered to tab1 as well.  In so doing,
+** the resulting tab1 has much less fragmentation.
+**
+** This routine returns TRUE if the optimization is attempted.  If any
+** of the conditions above fail so that the optimization should not
+** be attempted, then this routine returns FALSE.
+*/
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+){
+  ExprList *pEList;                /* The result set of the SELECT */
+  Table *pSrc;                     /* The table in the FROM clause of SELECT */
+  Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
+  struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
+  int i;                           /* Loop counter */
+  int iDbSrc;                      /* The database of pSrc */
+  int iSrc, iDest;                 /* Cursors from source and destination */
+  int addr1, addr2;                /* Loop addresses */
+  int emptyDestTest;               /* Address of test for empty pDest */
+  int emptySrcTest;                /* Address of test for empty pSrc */
+  Vdbe *v;                         /* The VDBE we are building */
+  KeyInfo *pKey;                   /* Key information for an index */
+  int regAutoinc;                  /* Memory register used by AUTOINC */
+  int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
+  int regData, regRowid;           /* Registers holding data and rowid */
+
+  if( pSelect==0 ){
+    return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
+  }
+  if( pDest->pTrigger ){
+    return 0;   /* tab1 must not have triggers */
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( pDest->isVirtual ){
+    return 0;   /* tab1 must not be a virtual table */
+  }
+#endif
+  if( onError==OE_Default ){
+    onError = OE_Abort;
+  }
+  if( onError!=OE_Abort && onError!=OE_Rollback ){
+    return 0;   /* Cannot do OR REPLACE or OR IGNORE or OR FAIL */
+  }
+  assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
+  if( pSelect->pSrc->nSrc!=1 ){
+    return 0;   /* FROM clause must have exactly one term */
+  }
+  if( pSelect->pSrc->a[0].pSelect ){
+    return 0;   /* FROM clause cannot contain a subquery */
+  }
+  if( pSelect->pWhere ){
+    return 0;   /* SELECT may not have a WHERE clause */
+  }
+  if( pSelect->pOrderBy ){
+    return 0;   /* SELECT may not have an ORDER BY clause */
+  }
+  /* Do not need to test for a HAVING clause.  If HAVING is present but
+  ** there is no ORDER BY, we will get an error. */
+  if( pSelect->pGroupBy ){
+    return 0;   /* SELECT may not have a GROUP BY clause */
+  }
+  if( pSelect->pLimit ){
+    return 0;   /* SELECT may not have a LIMIT clause */
+  }
+  assert( pSelect->pOffset==0 );  /* Must be so if pLimit==0 */
+  if( pSelect->pPrior ){
+    return 0;   /* SELECT may not be a compound query */
+  }
+  if( pSelect->isDistinct ){
+    return 0;   /* SELECT may not be DISTINCT */
+  }
+  pEList = pSelect->pEList;
+  assert( pEList!=0 );
+  if( pEList->nExpr!=1 ){
+    return 0;   /* The result set must have exactly one column */
+  }
+  assert( pEList->a[0].pExpr );
+  if( pEList->a[0].pExpr->op!=TK_ALL ){
+    return 0;   /* The result set must be the special operator "*" */
+  }
+
+  /* At this point we have established that the statement is of the
+  ** correct syntactic form to participate in this optimization.  Now
+  ** we have to check the semantics.
+  */
+  pItem = pSelect->pSrc->a;
+  pSrc = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
+  if( pSrc==0 ){
+    return 0;   /* FROM clause does not contain a real table */
+  }
+  if( pSrc==pDest ){
+    return 0;   /* tab1 and tab2 may not be the same table */
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( pSrc->isVirtual ){
+    return 0;   /* tab2 must not be a virtual table */
+  }
+#endif
+  if( pSrc->pSelect ){
+    return 0;   /* tab2 may not be a view */
+  }
+  if( pDest->nCol!=pSrc->nCol ){
+    return 0;   /* Number of columns must be the same in tab1 and tab2 */
+  }
+  if( pDest->iPKey!=pSrc->iPKey ){
+    return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
+  }
+  for(i=0; i<pDest->nCol; i++){
+    if( pDest->aCol[i].affinity!=pSrc->aCol[i].affinity ){
+      return 0;    /* Affinity must be the same on all columns */
+    }
+    if( !xferCompatibleCollation(pDest->aCol[i].zColl, pSrc->aCol[i].zColl) ){
+      return 0;    /* Collating sequence must be the same on all columns */
+    }
+    if( pDest->aCol[i].notNull && !pSrc->aCol[i].notNull ){
+      return 0;    /* tab2 must be NOT NULL if tab1 is */
+    }
+  }
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    if( pDestIdx->onError!=OE_None ){
+      destHasUniqueIdx = 1;
+    }
+    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    if( pSrcIdx==0 ){
+      return 0;    /* pDestIdx has no corresponding index in pSrc */
+    }
+  }
+#ifndef SQLITE_OMIT_CHECK
+  if( pDest->pCheck && !sqlite3ExprCompare(pSrc->pCheck, pDest->pCheck) ){
+    return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
+  }
+#endif
+
+  /* If we get this far, it means either:
+  **
+  **    *   We can always do the transfer if the table contains an
+  **        an integer primary key
+  **
+  **    *   We can conditionally do the transfer if the destination
+  **        table is empty.
+  */
+#ifdef SQLITE_TEST
+  sqlite3_xferopt_count++;
+#endif
+  iDbSrc = sqlite3SchemaToIndex(pParse->db, pSrc->pSchema);
+  v = sqlite3GetVdbe(pParse);
+  sqlite3CodeVerifySchema(pParse, iDbSrc);
+  iSrc = pParse->nTab++;
+  iDest = pParse->nTab++;
+  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
+  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
+  if( (pDest->iPKey<0 && pDest->pIndex!=0) || destHasUniqueIdx ){
+    /* If tables do not have an INTEGER PRIMARY KEY and there
+    ** are indices to be copied and the destination is not empty,
+    ** we have to disallow the transfer optimization because the
+    ** the rowids might change which will mess up indexing.
+    **
+    ** Or if the destination has a UNIQUE index and is not empty,
+    ** we also disallow the transfer optimization because we cannot
+    ** insure that all entries in the union of DEST and SRC will be
+    ** unique.
+    */
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0);
+    emptyDestTest = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
+    sqlite3VdbeJumpHere(v, addr1);
+  }else{
+    emptyDestTest = 0;
+  }
+  sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
+  emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
+  regData = sqlite3GetTempReg(pParse);
+  regRowid = sqlite3GetTempReg(pParse);
+  if( pDest->iPKey>=0 ){
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+    addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
+    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
+                      "PRIMARY KEY must be unique", P4_STATIC);
+    sqlite3VdbeJumpHere(v, addr2);
+    autoIncStep(pParse, regAutoinc, regRowid);
+  }else if( pDest->pIndex==0 ){
+    addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
+  }else{
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+    assert( pDest->autoInc==0 );
+  }
+  sqlite3VdbeAddOp2(v, OP_RowData, iSrc, regData);
+  sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
+  sqlite3VdbeChangeP5(v, OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND);
+  sqlite3VdbeChangeP4(v, -1, pDest->zName, 0);
+  sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1);
+  autoIncEnd(pParse, iDbDest, pDest, regAutoinc);
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    assert( pSrcIdx );
+    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+    pKey = sqlite3IndexKeyinfo(pParse, pSrcIdx);
+    sqlite3VdbeAddOp4(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc,
+                      (char*)pKey, P4_KEYINFO_HANDOFF);
+    VdbeComment((v, "%s", pSrcIdx->zName));
+    pKey = sqlite3IndexKeyinfo(pParse, pDestIdx);
+    sqlite3VdbeAddOp4(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest,
+                      (char*)pKey, P4_KEYINFO_HANDOFF);
+    VdbeComment((v, "%s", pDestIdx->zName));
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
+    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
+    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1);
+    sqlite3VdbeJumpHere(v, addr1);
+  }
+  sqlite3VdbeJumpHere(v, emptySrcTest);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+  sqlite3ReleaseTempReg(pParse, regData);
+  sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+  sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+  if( emptyDestTest ){
+    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
+    sqlite3VdbeJumpHere(v, emptyDestTest);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+/* Make sure "isView" gets undefined in case this file becomes part of
+** the amalgamation - so that subsequent files do not see isView as a
+** macro. */
+#undef isView
+
+/************** End of insert.c **********************************************/
+/************** Begin file legacy.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+**
+** $Id: legacy.c,v 1.24 2008/03/21 18:01:14 drh Exp $
+*/
+
+
+/*
+** Execute SQL code.  Return one of the SQLITE_ success/failure
+** codes.  Also write an error message into memory obtained from
+** malloc() and make *pzErrMsg point to that message.
+**
+** If the SQL is a query, then for each row in the query result
+** the xCallback() function is called.  pArg becomes the first
+** argument to xCallback().  If xCallback=NULL then no callback
+** is invoked, even for queries.
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  sqlite3_callback xCallback, /* Invoke this callback routine */
+  void *pArg,                 /* First argument to xCallback() */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc = SQLITE_OK;
+  const char *zLeftover;
+  sqlite3_stmt *pStmt = 0;
+  char **azCols = 0;
+
+  int nRetry = 0;
+  int nCallback;
+
+  if( zSql==0 ) return SQLITE_OK;
+
+  sqlite3_mutex_enter(db->mutex);
+  while( (rc==SQLITE_OK || (rc==SQLITE_SCHEMA && (++nRetry)<2)) && zSql[0] ){
+    int nCol;
+    char **azVals = 0;
+
+    pStmt = 0;
+    rc = sqlite3_prepare(db, zSql, -1, &pStmt, &zLeftover);
+    assert( rc==SQLITE_OK || pStmt==0 );
+    if( rc!=SQLITE_OK ){
+      continue;
+    }
+    if( !pStmt ){
+      /* this happens for a comment or white-space */
+      zSql = zLeftover;
+      continue;
+    }
+
+    nCallback = 0;
+    nCol = sqlite3_column_count(pStmt);
+
+    while( 1 ){
+      int i;
+      rc = sqlite3_step(pStmt);
+
+      /* Invoke the callback function if required */
+      if( xCallback && (SQLITE_ROW==rc || 
+          (SQLITE_DONE==rc && !nCallback && db->flags&SQLITE_NullCallback)) ){
+        if( 0==nCallback ){
+          if( azCols==0 ){
+            azCols = sqlite3DbMallocZero(db, 2*nCol*sizeof(const char*) + 1);
+            if( azCols==0 ){
+              goto exec_out;
+            }
+          }
+          for(i=0; i<nCol; i++){
+            azCols[i] = (char *)sqlite3_column_name(pStmt, i);
+            if( !azCols[i] ){
+              db->mallocFailed = 1;
+              goto exec_out;
+            }
+          }
+          nCallback++;
+        }
+        if( rc==SQLITE_ROW ){
+          azVals = &azCols[nCol];
+          for(i=0; i<nCol; i++){
+            azVals[i] = (char *)sqlite3_column_text(pStmt, i);
+            if( !azVals[i] && sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
+              db->mallocFailed = 1;
+              goto exec_out;
+            }
+          }
+        }
+        if( xCallback(pArg, nCol, azVals, azCols) ){
+          rc = SQLITE_ABORT;
+          goto exec_out;
+        }
+      }
+
+      if( rc!=SQLITE_ROW ){
+        rc = sqlite3_finalize(pStmt);
+        pStmt = 0;
+        if( rc!=SQLITE_SCHEMA ){
+          nRetry = 0;
+          zSql = zLeftover;
+          while( isspace((unsigned char)zSql[0]) ) zSql++;
+        }
+        break;
+      }
+    }
+
+    sqlite3_free(azCols);
+    azCols = 0;
+  }
+
+exec_out:
+  if( pStmt ) sqlite3_finalize(pStmt);
+  if( azCols ) sqlite3_free(azCols);
+
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && rc==sqlite3_errcode(db) && pzErrMsg ){
+    int nErrMsg = 1 + strlen(sqlite3_errmsg(db));
+    *pzErrMsg = sqlite3_malloc(nErrMsg);
+    if( *pzErrMsg ){
+      memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);
+    }
+  }else if( pzErrMsg ){
+    *pzErrMsg = 0;
+  }
+
+  assert( (rc&db->errMask)==rc );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/************** End of legacy.c **********************************************/
+/************** Begin file loadext.c *****************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to dynamically load extensions into
+** the SQLite library.
+*/
+
+#ifndef SQLITE_CORE
+  #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
+#endif
+/************** Include sqlite3ext.h in the middle of loadext.c **************/
+/************** Begin file sqlite3ext.h **************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the SQLite interface for use by
+** shared libraries that want to be imported as extensions into
+** an SQLite instance.  Shared libraries that intend to be loaded
+** as extensions by SQLite should #include this file instead of 
+** sqlite3.h.
+**
+** @(#) $Id: sqlite3ext.h,v 1.21 2008/03/19 21:45:51 drh Exp $
+*/
+#ifndef _SQLITE3EXT_H_
+#define _SQLITE3EXT_H_
+
+typedef struct sqlite3_api_routines sqlite3_api_routines;
+
+/*
+** The following structure holds pointers to all of the SQLite API
+** routines.
+**
+** WARNING:  In order to maintain backwards compatibility, add new
+** interfaces to the end of this structure only.  If you insert new
+** interfaces in the middle of this structure, then older different
+** versions of SQLite will not be able to load each others' shared
+** libraries!
+*/
+struct sqlite3_api_routines {
+  void * (*aggregate_context)(sqlite3_context*,int nBytes);
+  int  (*aggregate_count)(sqlite3_context*);
+  int  (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
+  int  (*bind_double)(sqlite3_stmt*,int,double);
+  int  (*bind_int)(sqlite3_stmt*,int,int);
+  int  (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
+  int  (*bind_null)(sqlite3_stmt*,int);
+  int  (*bind_parameter_count)(sqlite3_stmt*);
+  int  (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
+  const char * (*bind_parameter_name)(sqlite3_stmt*,int);
+  int  (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
+  int  (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
+  int  (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
+  int  (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
+  int  (*busy_timeout)(sqlite3*,int ms);
+  int  (*changes)(sqlite3*);
+  int  (*close)(sqlite3*);
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const void*));
+  const void * (*column_blob)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes16)(sqlite3_stmt*,int iCol);
+  int  (*column_count)(sqlite3_stmt*pStmt);
+  const char * (*column_database_name)(sqlite3_stmt*,int);
+  const void * (*column_database_name16)(sqlite3_stmt*,int);
+  const char * (*column_decltype)(sqlite3_stmt*,int i);
+  const void * (*column_decltype16)(sqlite3_stmt*,int);
+  double  (*column_double)(sqlite3_stmt*,int iCol);
+  int  (*column_int)(sqlite3_stmt*,int iCol);
+  sqlite_int64  (*column_int64)(sqlite3_stmt*,int iCol);
+  const char * (*column_name)(sqlite3_stmt*,int);
+  const void * (*column_name16)(sqlite3_stmt*,int);
+  const char * (*column_origin_name)(sqlite3_stmt*,int);
+  const void * (*column_origin_name16)(sqlite3_stmt*,int);
+  const char * (*column_table_name)(sqlite3_stmt*,int);
+  const void * (*column_table_name16)(sqlite3_stmt*,int);
+  const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
+  const void * (*column_text16)(sqlite3_stmt*,int iCol);
+  int  (*column_type)(sqlite3_stmt*,int iCol);
+  sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
+  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
+  int  (*complete)(const char*sql);
+  int  (*complete16)(const void*sql);
+  int  (*create_collation)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
+  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
+  int  (*data_count)(sqlite3_stmt*pStmt);
+  sqlite3 * (*db_handle)(sqlite3_stmt*);
+  int (*declare_vtab)(sqlite3*,const char*);
+  int  (*enable_shared_cache)(int);
+  int  (*errcode)(sqlite3*db);
+  const char * (*errmsg)(sqlite3*);
+  const void * (*errmsg16)(sqlite3*);
+  int  (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
+  int  (*expired)(sqlite3_stmt*);
+  int  (*finalize)(sqlite3_stmt*pStmt);
+  void  (*free)(void*);
+  void  (*free_table)(char**result);
+  int  (*get_autocommit)(sqlite3*);
+  void * (*get_auxdata)(sqlite3_context*,int);
+  int  (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
+  int  (*global_recover)(void);
+  void  (*interruptx)(sqlite3*);
+  sqlite_int64  (*last_insert_rowid)(sqlite3*);
+  const char * (*libversion)(void);
+  int  (*libversion_number)(void);
+  void *(*malloc)(int);
+  char * (*mprintf)(const char*,...);
+  int  (*open)(const char*,sqlite3**);
+  int  (*open16)(const void*,sqlite3**);
+  int  (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int  (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
+  void  (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
+  void *(*realloc)(void*,int);
+  int  (*reset)(sqlite3_stmt*pStmt);
+  void  (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_double)(sqlite3_context*,double);
+  void  (*result_error)(sqlite3_context*,const char*,int);
+  void  (*result_error16)(sqlite3_context*,const void*,int);
+  void  (*result_int)(sqlite3_context*,int);
+  void  (*result_int64)(sqlite3_context*,sqlite_int64);
+  void  (*result_null)(sqlite3_context*);
+  void  (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
+  void  (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_value)(sqlite3_context*,sqlite3_value*);
+  void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,const char*,const char*),void*);
+  void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
+  char * (*snprintf)(int,char*,const char*,...);
+  int  (*step)(sqlite3_stmt*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,char const**,char const**,int*,int*,int*);
+  void  (*thread_cleanup)(void);
+  int  (*total_changes)(sqlite3*);
+  void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
+  int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,sqlite_int64),void*);
+  void * (*user_data)(sqlite3_context*);
+  const void * (*value_blob)(sqlite3_value*);
+  int  (*value_bytes)(sqlite3_value*);
+  int  (*value_bytes16)(sqlite3_value*);
+  double  (*value_double)(sqlite3_value*);
+  int  (*value_int)(sqlite3_value*);
+  sqlite_int64  (*value_int64)(sqlite3_value*);
+  int  (*value_numeric_type)(sqlite3_value*);
+  const unsigned char * (*value_text)(sqlite3_value*);
+  const void * (*value_text16)(sqlite3_value*);
+  const void * (*value_text16be)(sqlite3_value*);
+  const void * (*value_text16le)(sqlite3_value*);
+  int  (*value_type)(sqlite3_value*);
+  char *(*vmprintf)(const char*,va_list);
+  /* Added ??? */
+  int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
+  /* Added by 3.3.13 */
+  int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  int (*clear_bindings)(sqlite3_stmt*);
+  /* Added by 3.4.1 */
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,void (*xDestroy)(void *));
+  /* Added by 3.5.0 */
+  int (*bind_zeroblob)(sqlite3_stmt*,int,int);
+  int (*blob_bytes)(sqlite3_blob*);
+  int (*blob_close)(sqlite3_blob*);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,int,sqlite3_blob**);
+  int (*blob_read)(sqlite3_blob*,void*,int,int);
+  int (*blob_write)(sqlite3_blob*,const void*,int,int);
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*),void(*)(void*));
+  int (*file_control)(sqlite3*,const char*,int,void*);
+  sqlite3_int64 (*memory_highwater)(int);
+  sqlite3_int64 (*memory_used)(void);
+  sqlite3_mutex *(*mutex_alloc)(int);
+  void (*mutex_enter)(sqlite3_mutex*);
+  void (*mutex_free)(sqlite3_mutex*);
+  void (*mutex_leave)(sqlite3_mutex*);
+  int (*mutex_try)(sqlite3_mutex*);
+  int (*open_v2)(const char*,sqlite3**,int,const char*);
+  int (*release_memory)(int);
+  void (*result_error_nomem)(sqlite3_context*);
+  void (*result_error_toobig)(sqlite3_context*);
+  int (*sleep)(int);
+  void (*soft_heap_limit)(int);
+  sqlite3_vfs *(*vfs_find)(const char*);
+  int (*vfs_register)(sqlite3_vfs*,int);
+  int (*vfs_unregister)(sqlite3_vfs*);
+  int (*xthreadsafe)(void);
+  void (*result_zeroblob)(sqlite3_context*,int);
+  void (*result_error_code)(sqlite3_context*,int);
+  int (*test_control)(int, ...);
+  void (*randomness)(int,void*);
+  sqlite3 *(*context_db_handle)(sqlite3_context*);
+};
+
+/*
+** The following macros redefine the API routines so that they are
+** redirected throught the global sqlite3_api structure.
+**
+** This header file is also used by the loadext.c source file
+** (part of the main SQLite library - not an extension) so that
+** it can get access to the sqlite3_api_routines structure
+** definition.  But the main library does not want to redefine
+** the API.  So the redefinition macros are only valid if the
+** SQLITE_CORE macros is undefined.
+*/
+#ifndef SQLITE_CORE
+#define sqlite3_aggregate_context      sqlite3_api->aggregate_context
+#define sqlite3_aggregate_count        sqlite3_api->aggregate_count
+#define sqlite3_bind_blob              sqlite3_api->bind_blob
+#define sqlite3_bind_double            sqlite3_api->bind_double
+#define sqlite3_bind_int               sqlite3_api->bind_int
+#define sqlite3_bind_int64             sqlite3_api->bind_int64
+#define sqlite3_bind_null              sqlite3_api->bind_null
+#define sqlite3_bind_parameter_count   sqlite3_api->bind_parameter_count
+#define sqlite3_bind_parameter_index   sqlite3_api->bind_parameter_index
+#define sqlite3_bind_parameter_name    sqlite3_api->bind_parameter_name
+#define sqlite3_bind_text              sqlite3_api->bind_text
+#define sqlite3_bind_text16            sqlite3_api->bind_text16
+#define sqlite3_bind_value             sqlite3_api->bind_value
+#define sqlite3_busy_handler           sqlite3_api->busy_handler
+#define sqlite3_busy_timeout           sqlite3_api->busy_timeout
+#define sqlite3_changes                sqlite3_api->changes
+#define sqlite3_close                  sqlite3_api->close
+#define sqlite3_collation_needed       sqlite3_api->collation_needed
+#define sqlite3_collation_needed16     sqlite3_api->collation_needed16
+#define sqlite3_column_blob            sqlite3_api->column_blob
+#define sqlite3_column_bytes           sqlite3_api->column_bytes
+#define sqlite3_column_bytes16         sqlite3_api->column_bytes16
+#define sqlite3_column_count           sqlite3_api->column_count
+#define sqlite3_column_database_name   sqlite3_api->column_database_name
+#define sqlite3_column_database_name16 sqlite3_api->column_database_name16
+#define sqlite3_column_decltype        sqlite3_api->column_decltype
+#define sqlite3_column_decltype16      sqlite3_api->column_decltype16
+#define sqlite3_column_double          sqlite3_api->column_double
+#define sqlite3_column_int             sqlite3_api->column_int
+#define sqlite3_column_int64           sqlite3_api->column_int64
+#define sqlite3_column_name            sqlite3_api->column_name
+#define sqlite3_column_name16          sqlite3_api->column_name16
+#define sqlite3_column_origin_name     sqlite3_api->column_origin_name
+#define sqlite3_column_origin_name16   sqlite3_api->column_origin_name16
+#define sqlite3_column_table_name      sqlite3_api->column_table_name
+#define sqlite3_column_table_name16    sqlite3_api->column_table_name16
+#define sqlite3_column_text            sqlite3_api->column_text
+#define sqlite3_column_text16          sqlite3_api->column_text16
+#define sqlite3_column_type            sqlite3_api->column_type
+#define sqlite3_column_value           sqlite3_api->column_value
+#define sqlite3_commit_hook            sqlite3_api->commit_hook
+#define sqlite3_complete               sqlite3_api->complete
+#define sqlite3_complete16             sqlite3_api->complete16
+#define sqlite3_create_collation       sqlite3_api->create_collation
+#define sqlite3_create_collation16     sqlite3_api->create_collation16
+#define sqlite3_create_function        sqlite3_api->create_function
+#define sqlite3_create_function16      sqlite3_api->create_function16
+#define sqlite3_create_module          sqlite3_api->create_module
+#define sqlite3_create_module_v2       sqlite3_api->create_module_v2
+#define sqlite3_data_count             sqlite3_api->data_count
+#define sqlite3_db_handle              sqlite3_api->db_handle
+#define sqlite3_declare_vtab           sqlite3_api->declare_vtab
+#define sqlite3_enable_shared_cache    sqlite3_api->enable_shared_cache
+#define sqlite3_errcode                sqlite3_api->errcode
+#define sqlite3_errmsg                 sqlite3_api->errmsg
+#define sqlite3_errmsg16               sqlite3_api->errmsg16
+#define sqlite3_exec                   sqlite3_api->exec
+#define sqlite3_expired                sqlite3_api->expired
+#define sqlite3_finalize               sqlite3_api->finalize
+#define sqlite3_free                   sqlite3_api->free
+#define sqlite3_free_table             sqlite3_api->free_table
+#define sqlite3_get_autocommit         sqlite3_api->get_autocommit
+#define sqlite3_get_auxdata            sqlite3_api->get_auxdata
+#define sqlite3_get_table              sqlite3_api->get_table
+#define sqlite3_global_recover         sqlite3_api->global_recover
+#define sqlite3_interrupt              sqlite3_api->interruptx
+#define sqlite3_last_insert_rowid      sqlite3_api->last_insert_rowid
+#define sqlite3_libversion             sqlite3_api->libversion
+#define sqlite3_libversion_number      sqlite3_api->libversion_number
+#define sqlite3_malloc                 sqlite3_api->malloc
+#define sqlite3_mprintf                sqlite3_api->mprintf
+#define sqlite3_open                   sqlite3_api->open
+#define sqlite3_open16                 sqlite3_api->open16
+#define sqlite3_prepare                sqlite3_api->prepare
+#define sqlite3_prepare16              sqlite3_api->prepare16
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_profile                sqlite3_api->profile
+#define sqlite3_progress_handler       sqlite3_api->progress_handler
+#define sqlite3_realloc                sqlite3_api->realloc
+#define sqlite3_reset                  sqlite3_api->reset
+#define sqlite3_result_blob            sqlite3_api->result_blob
+#define sqlite3_result_double          sqlite3_api->result_double
+#define sqlite3_result_error           sqlite3_api->result_error
+#define sqlite3_result_error16         sqlite3_api->result_error16
+#define sqlite3_result_int             sqlite3_api->result_int
+#define sqlite3_result_int64           sqlite3_api->result_int64
+#define sqlite3_result_null            sqlite3_api->result_null
+#define sqlite3_result_text            sqlite3_api->result_text
+#define sqlite3_result_text16          sqlite3_api->result_text16
+#define sqlite3_result_text16be        sqlite3_api->result_text16be
+#define sqlite3_result_text16le        sqlite3_api->result_text16le
+#define sqlite3_result_value           sqlite3_api->result_value
+#define sqlite3_rollback_hook          sqlite3_api->rollback_hook
+#define sqlite3_set_authorizer         sqlite3_api->set_authorizer
+#define sqlite3_set_auxdata            sqlite3_api->set_auxdata
+#define sqlite3_snprintf               sqlite3_api->snprintf
+#define sqlite3_step                   sqlite3_api->step
+#define sqlite3_table_column_metadata  sqlite3_api->table_column_metadata
+#define sqlite3_thread_cleanup         sqlite3_api->thread_cleanup
+#define sqlite3_total_changes          sqlite3_api->total_changes
+#define sqlite3_trace                  sqlite3_api->trace
+#define sqlite3_transfer_bindings      sqlite3_api->transfer_bindings
+#define sqlite3_update_hook            sqlite3_api->update_hook
+#define sqlite3_user_data              sqlite3_api->user_data
+#define sqlite3_value_blob             sqlite3_api->value_blob
+#define sqlite3_value_bytes            sqlite3_api->value_bytes
+#define sqlite3_value_bytes16          sqlite3_api->value_bytes16
+#define sqlite3_value_double           sqlite3_api->value_double
+#define sqlite3_value_int              sqlite3_api->value_int
+#define sqlite3_value_int64            sqlite3_api->value_int64
+#define sqlite3_value_numeric_type     sqlite3_api->value_numeric_type
+#define sqlite3_value_text             sqlite3_api->value_text
+#define sqlite3_value_text16           sqlite3_api->value_text16
+#define sqlite3_value_text16be         sqlite3_api->value_text16be
+#define sqlite3_value_text16le         sqlite3_api->value_text16le
+#define sqlite3_value_type             sqlite3_api->value_type
+#define sqlite3_vmprintf               sqlite3_api->vmprintf
+#define sqlite3_overload_function      sqlite3_api->overload_function
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_clear_bindings         sqlite3_api->clear_bindings
+#define sqlite3_bind_zeroblob          sqlite3_api->bind_zeroblob
+#define sqlite3_blob_bytes             sqlite3_api->blob_bytes
+#define sqlite3_blob_close             sqlite3_api->blob_close
+#define sqlite3_blob_open              sqlite3_api->blob_open
+#define sqlite3_blob_read              sqlite3_api->blob_read
+#define sqlite3_blob_write             sqlite3_api->blob_write
+#define sqlite3_create_collation_v2    sqlite3_api->create_collation_v2
+#define sqlite3_file_control           sqlite3_api->file_control
+#define sqlite3_memory_highwater       sqlite3_api->memory_highwater
+#define sqlite3_memory_used            sqlite3_api->memory_used
+#define sqlite3_mutex_alloc            sqlite3_api->mutex_alloc
+#define sqlite3_mutex_enter            sqlite3_api->mutex_enter
+#define sqlite3_mutex_free             sqlite3_api->mutex_free
+#define sqlite3_mutex_leave            sqlite3_api->mutex_leave
+#define sqlite3_mutex_try              sqlite3_api->mutex_try
+#define sqlite3_open_v2                sqlite3_api->open_v2
+#define sqlite3_release_memory         sqlite3_api->release_memory
+#define sqlite3_result_error_nomem     sqlite3_api->result_error_nomem
+#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig
+#define sqlite3_sleep                  sqlite3_api->sleep
+#define sqlite3_soft_heap_limit        sqlite3_api->soft_heap_limit
+#define sqlite3_vfs_find               sqlite3_api->vfs_find
+#define sqlite3_vfs_register           sqlite3_api->vfs_register
+#define sqlite3_vfs_unregister         sqlite3_api->vfs_unregister
+#define sqlite3_threadsafe             sqlite3_api->xthreadsafe
+#define sqlite3_result_zeroblob        sqlite3_api->result_zeroblob
+#define sqlite3_result_error_code      sqlite3_api->result_error_code
+#define sqlite3_test_control           sqlite3_api->test_control
+#define sqlite3_randomness             sqlite3_api->randomness
+#define sqlite3_context_db_handle      sqlite3_api->context_db_handle
+#endif /* SQLITE_CORE */
+
+#define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api;
+#define SQLITE_EXTENSION_INIT2(v)  sqlite3_api = v;
+
+#endif /* _SQLITE3EXT_H_ */
+
+/************** End of sqlite3ext.h ******************************************/
+/************** Continuing where we left off in loadext.c ********************/
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+
+/*
+** Some API routines are omitted when various features are
+** excluded from a build of SQLite.  Substitute a NULL pointer
+** for any missing APIs.
+*/
+#ifndef SQLITE_ENABLE_COLUMN_METADATA
+# define sqlite3_column_database_name   0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name      0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name     0
+# define sqlite3_column_origin_name16   0
+# define sqlite3_table_column_metadata  0
+#endif
+
+#ifdef SQLITE_OMIT_AUTHORIZATION
+# define sqlite3_set_authorizer         0
+#endif
+
+#ifdef SQLITE_OMIT_UTF16
+# define sqlite3_bind_text16            0
+# define sqlite3_collation_needed16     0
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_name16          0
+# define sqlite3_column_text16          0
+# define sqlite3_complete16             0
+# define sqlite3_create_collation16     0
+# define sqlite3_create_function16      0
+# define sqlite3_errmsg16               0
+# define sqlite3_open16                 0
+# define sqlite3_prepare16              0
+# define sqlite3_prepare16_v2           0
+# define sqlite3_result_error16         0
+# define sqlite3_result_text16          0
+# define sqlite3_result_text16be        0
+# define sqlite3_result_text16le        0
+# define sqlite3_value_text16           0
+# define sqlite3_value_text16be         0
+# define sqlite3_value_text16le         0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name16   0
+#endif
+
+#ifdef SQLITE_OMIT_COMPLETE
+# define sqlite3_complete 0
+# define sqlite3_complete16 0
+#endif
+
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+# define sqlite3_progress_handler 0
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# define sqlite3_create_module 0
+# define sqlite3_create_module_v2 0
+# define sqlite3_declare_vtab 0
+#endif
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+# define sqlite3_enable_shared_cache 0
+#endif
+
+#ifdef SQLITE_OMIT_TRACE
+# define sqlite3_profile       0
+# define sqlite3_trace         0
+#endif
+
+#ifdef SQLITE_OMIT_GET_TABLE
+# define sqlite3_free_table    0
+# define sqlite3_get_table     0
+#endif
+
+#ifdef SQLITE_OMIT_INCRBLOB
+#define sqlite3_bind_zeroblob  0
+#define sqlite3_blob_bytes     0
+#define sqlite3_blob_close     0
+#define sqlite3_blob_open      0
+#define sqlite3_blob_read      0
+#define sqlite3_blob_write     0
+#endif
+
+/*
+** The following structure contains pointers to all SQLite API routines.
+** A pointer to this structure is passed into extensions when they are
+** loaded so that the extension can make calls back into the SQLite
+** library.
+**
+** When adding new APIs, add them to the bottom of this structure
+** in order to preserve backwards compatibility.
+**
+** Extensions that use newer APIs should first call the
+** sqlite3_libversion_number() to make sure that the API they
+** intend to use is supported by the library.  Extensions should
+** also check to make sure that the pointer to the function is
+** not NULL before calling it.
+*/
+static const sqlite3_api_routines sqlite3Apis = {
+  sqlite3_aggregate_context,
+  sqlite3_aggregate_count,
+  sqlite3_bind_blob,
+  sqlite3_bind_double,
+  sqlite3_bind_int,
+  sqlite3_bind_int64,
+  sqlite3_bind_null,
+  sqlite3_bind_parameter_count,
+  sqlite3_bind_parameter_index,
+  sqlite3_bind_parameter_name,
+  sqlite3_bind_text,
+  sqlite3_bind_text16,
+  sqlite3_bind_value,
+  sqlite3_busy_handler,
+  sqlite3_busy_timeout,
+  sqlite3_changes,
+  sqlite3_close,
+  sqlite3_collation_needed,
+  sqlite3_collation_needed16,
+  sqlite3_column_blob,
+  sqlite3_column_bytes,
+  sqlite3_column_bytes16,
+  sqlite3_column_count,
+  sqlite3_column_database_name,
+  sqlite3_column_database_name16,
+  sqlite3_column_decltype,
+  sqlite3_column_decltype16,
+  sqlite3_column_double,
+  sqlite3_column_int,
+  sqlite3_column_int64,
+  sqlite3_column_name,
+  sqlite3_column_name16,
+  sqlite3_column_origin_name,
+  sqlite3_column_origin_name16,
+  sqlite3_column_table_name,
+  sqlite3_column_table_name16,
+  sqlite3_column_text,
+  sqlite3_column_text16,
+  sqlite3_column_type,
+  sqlite3_column_value,
+  sqlite3_commit_hook,
+  sqlite3_complete,
+  sqlite3_complete16,
+  sqlite3_create_collation,
+  sqlite3_create_collation16,
+  sqlite3_create_function,
+  sqlite3_create_function16,
+  sqlite3_create_module,
+  sqlite3_data_count,
+  sqlite3_db_handle,
+  sqlite3_declare_vtab,
+  sqlite3_enable_shared_cache,
+  sqlite3_errcode,
+  sqlite3_errmsg,
+  sqlite3_errmsg16,
+  sqlite3_exec,
+  sqlite3_expired,
+  sqlite3_finalize,
+  sqlite3_free,
+  sqlite3_free_table,
+  sqlite3_get_autocommit,
+  sqlite3_get_auxdata,
+  sqlite3_get_table,
+  0,     /* Was sqlite3_global_recover(), but that function is deprecated */
+  sqlite3_interrupt,
+  sqlite3_last_insert_rowid,
+  sqlite3_libversion,
+  sqlite3_libversion_number,
+  sqlite3_malloc,
+  sqlite3_mprintf,
+  sqlite3_open,
+  sqlite3_open16,
+  sqlite3_prepare,
+  sqlite3_prepare16,
+  sqlite3_profile,
+  sqlite3_progress_handler,
+  sqlite3_realloc,
+  sqlite3_reset,
+  sqlite3_result_blob,
+  sqlite3_result_double,
+  sqlite3_result_error,
+  sqlite3_result_error16,
+  sqlite3_result_int,
+  sqlite3_result_int64,
+  sqlite3_result_null,
+  sqlite3_result_text,
+  sqlite3_result_text16,
+  sqlite3_result_text16be,
+  sqlite3_result_text16le,
+  sqlite3_result_value,
+  sqlite3_rollback_hook,
+  sqlite3_set_authorizer,
+  sqlite3_set_auxdata,
+  sqlite3_snprintf,
+  sqlite3_step,
+  sqlite3_table_column_metadata,
+  sqlite3_thread_cleanup,
+  sqlite3_total_changes,
+  sqlite3_trace,
+  sqlite3_transfer_bindings,
+  sqlite3_update_hook,
+  sqlite3_user_data,
+  sqlite3_value_blob,
+  sqlite3_value_bytes,
+  sqlite3_value_bytes16,
+  sqlite3_value_double,
+  sqlite3_value_int,
+  sqlite3_value_int64,
+  sqlite3_value_numeric_type,
+  sqlite3_value_text,
+  sqlite3_value_text16,
+  sqlite3_value_text16be,
+  sqlite3_value_text16le,
+  sqlite3_value_type,
+  sqlite3_vmprintf,
+  /*
+  ** The original API set ends here.  All extensions can call any
+  ** of the APIs above provided that the pointer is not NULL.  But
+  ** before calling APIs that follow, extension should check the
+  ** sqlite3_libversion_number() to make sure they are dealing with
+  ** a library that is new enough to support that API.
+  *************************************************************************
+  */
+  sqlite3_overload_function,
+
+  /*
+  ** Added after 3.3.13
+  */
+  sqlite3_prepare_v2,
+  sqlite3_prepare16_v2,
+  sqlite3_clear_bindings,
+
+  /*
+  ** Added for 3.4.1
+  */
+  sqlite3_create_module_v2,
+
+  /*
+  ** Added for 3.5.0
+  */
+  sqlite3_bind_zeroblob,
+  sqlite3_blob_bytes,
+  sqlite3_blob_close,
+  sqlite3_blob_open,
+  sqlite3_blob_read,
+  sqlite3_blob_write,
+  sqlite3_create_collation_v2,
+  sqlite3_file_control,
+  sqlite3_memory_highwater,
+  sqlite3_memory_used,
+#ifdef SQLITE_MUTEX_NOOP
+  0, 
+  0, 
+  0,
+  0,
+  0,
+#else
+  sqlite3_mutex_alloc,
+  sqlite3_mutex_enter,
+  sqlite3_mutex_free,
+  sqlite3_mutex_leave,
+  sqlite3_mutex_try,
+#endif
+  sqlite3_open_v2,
+  sqlite3_release_memory,
+  sqlite3_result_error_nomem,
+  sqlite3_result_error_toobig,
+  sqlite3_sleep,
+  sqlite3_soft_heap_limit,
+  sqlite3_vfs_find,
+  sqlite3_vfs_register,
+  sqlite3_vfs_unregister,
+
+  /*
+  ** Added for 3.5.8
+  */
+  sqlite3_threadsafe,
+  sqlite3_result_zeroblob,
+  sqlite3_result_error_code,
+  sqlite3_test_control,
+  sqlite3_randomness,
+  sqlite3_context_db_handle,
+};
+
+/*
+** Attempt to load an SQLite extension library contained in the file
+** zFile.  The entry point is zProc.  zProc may be 0 in which case a
+** default entry point name (sqlite3_extension_init) is used.  Use
+** of the default name is recommended.
+**
+** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
+**
+** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with 
+** error message text.  The calling function should free this memory
+** by calling sqlite3_free().
+*/
+static int sqlite3LoadExtension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  sqlite3_vfs *pVfs = db->pVfs;
+  void *handle;
+  int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
+  char *zErrmsg = 0;
+  void **aHandle;
+
+  /* Ticket #1863.  To avoid a creating security problems for older
+  ** applications that relink against newer versions of SQLite, the
+  ** ability to run load_extension is turned off by default.  One
+  ** must call sqlite3_enable_load_extension() to turn on extension
+  ** loading.  Otherwise you get the following error.
+  */
+  if( (db->flags & SQLITE_LoadExtension)==0 ){
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("not authorized");
+    }
+    return SQLITE_ERROR;
+  }
+
+  if( zProc==0 ){
+    zProc = "sqlite3_extension_init";
+  }
+
+  handle = sqlite3OsDlOpen(pVfs, zFile);
+  if( handle==0 ){
+    if( pzErrMsg ){
+      char zErr[256];
+      zErr[sizeof(zErr)-1] = '\0';
+      sqlite3_snprintf(sizeof(zErr)-1, zErr, 
+          "unable to open shared library [%s]", zFile);
+      sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);
+      *pzErrMsg = sqlite3DbStrDup(db, zErr);
+    }
+    return SQLITE_ERROR;
+  }
+  xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
+                   sqlite3OsDlSym(pVfs, handle, zProc);
+  if( xInit==0 ){
+    if( pzErrMsg ){
+      char zErr[256];
+      zErr[sizeof(zErr)-1] = '\0';
+      sqlite3_snprintf(sizeof(zErr)-1, zErr,
+          "no entry point [%s] in shared library [%s]", zProc,zFile);
+      sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);
+      *pzErrMsg = sqlite3DbStrDup(db, zErr);
+      sqlite3OsDlClose(pVfs, handle);
+    }
+    return SQLITE_ERROR;
+  }else if( xInit(db, &zErrmsg, &sqlite3Apis) ){
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
+    }
+    sqlite3_free(zErrmsg);
+    sqlite3OsDlClose(pVfs, handle);
+    return SQLITE_ERROR;
+  }
+
+  /* Append the new shared library handle to the db->aExtension array. */
+  db->nExtension++;
+  aHandle = sqlite3DbMallocZero(db, sizeof(handle)*db->nExtension);
+  if( aHandle==0 ){
+    return SQLITE_NOMEM;
+  }
+  if( db->nExtension>0 ){
+    memcpy(aHandle, db->aExtension, sizeof(handle)*(db->nExtension-1));
+  }
+  sqlite3_free(db->aExtension);
+  db->aExtension = aHandle;
+
+  db->aExtension[db->nExtension-1] = handle;
+  return SQLITE_OK;
+}
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Call this routine when the database connection is closing in order
+** to clean up loaded extensions
+*/
+SQLITE_PRIVATE void sqlite3CloseExtensions(sqlite3 *db){
+  int i;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nExtension; i++){
+    sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
+  }
+  sqlite3_free(db->aExtension);
+}
+
+/*
+** Enable or disable extension loading.  Extension loading is disabled by
+** default so as not to open security holes in older applications.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
+  sqlite3_mutex_enter(db->mutex);
+  if( onoff ){
+    db->flags |= SQLITE_LoadExtension;
+  }else{
+    db->flags &= ~SQLITE_LoadExtension;
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+
+/*
+** The auto-extension code added regardless of whether or not extension
+** loading is supported.  We need a dummy sqlite3Apis pointer for that
+** code if regular extension loading is not available.  This is that
+** dummy pointer.
+*/
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+static const sqlite3_api_routines sqlite3Apis = { 0 };
+#endif
+
+
+/*
+** The following object holds the list of automatically loaded
+** extensions.
+**
+** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
+** mutex must be held while accessing this list.
+*/
+static struct {
+  int nExt;        /* Number of entries in aExt[] */          
+  void **aExt;     /* Pointers to the extension init functions */
+} autoext = { 0, 0 };
+
+
+/*
+** Register a statically linked extension that is automatically
+** loaded by every new database connection.
+*/
+SQLITE_API int sqlite3_auto_extension(void *xInit){
+  int i;
+  int rc = SQLITE_OK;
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=0; i<autoext.nExt; i++){
+    if( autoext.aExt[i]==xInit ) break;
+  }
+  if( i==autoext.nExt ){
+    int nByte = (autoext.nExt+1)*sizeof(autoext.aExt[0]);
+    void **aNew;
+    aNew = sqlite3_realloc(autoext.aExt, nByte);
+    if( aNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      autoext.aExt = aNew;
+      autoext.aExt[autoext.nExt] = xInit;
+      autoext.nExt++;
+    }
+  }
+  sqlite3_mutex_leave(mutex);
+  assert( (rc&0xff)==rc );
+  return rc;
+}
+
+/*
+** Reset the automatic extension loading mechanism.
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void){
+#ifndef SQLITE_MUTEX_NOOP
+  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_mutex_enter(mutex);
+  sqlite3_free(autoext.aExt);
+  autoext.aExt = 0;
+  autoext.nExt = 0;
+  sqlite3_mutex_leave(mutex);
+}
+
+/*
+** Load all automatic extensions.
+*/
+SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3 *db){
+  int i;
+  int go = 1;
+  int rc = SQLITE_OK;
+  int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
+
+  if( autoext.nExt==0 ){
+    /* Common case: early out without every having to acquire a mutex */
+    return SQLITE_OK;
+  }
+  for(i=0; go; i++){
+    char *zErrmsg = 0;
+#ifndef SQLITE_MUTEX_NOOP
+    sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+    sqlite3_mutex_enter(mutex);
+    if( i>=autoext.nExt ){
+      xInit = 0;
+      go = 0;
+    }else{
+      xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
+              autoext.aExt[i];
+    }
+    sqlite3_mutex_leave(mutex);
+    if( xInit && xInit(db, &zErrmsg, &sqlite3Apis) ){
+      sqlite3Error(db, SQLITE_ERROR,
+            "automatic extension loading failed: %s", zErrmsg);
+      go = 0;
+      rc = SQLITE_ERROR;
+      sqlite3_free(zErrmsg);
+    }
+  }
+  return rc;
+}
+
+/************** End of loadext.c *********************************************/
+/************** Begin file pragma.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the PRAGMA command.
+**
+** $Id: pragma.c,v 1.176 2008/04/17 20:59:38 drh Exp $
+*/
+
+/* Ignore this whole file if pragmas are disabled
+*/
+#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)
+
+/*
+** Interpret the given string as a safety level.  Return 0 for OFF,
+** 1 for ON or NORMAL and 2 for FULL.  Return 1 for an empty or 
+** unrecognized string argument.
+**
+** Note that the values returned are one less that the values that
+** should be passed into sqlite3BtreeSetSafetyLevel().  The is done
+** to support legacy SQL code.  The safety level used to be boolean
+** and older scripts may have used numbers 0 for OFF and 1 for ON.
+*/
+static int getSafetyLevel(const char *z){
+                             /* 123456789 123456789 */
+  static const char zText[] = "onoffalseyestruefull";
+  static const u8 iOffset[] = {0, 1, 2, 4, 9, 12, 16};
+  static const u8 iLength[] = {2, 2, 3, 5, 3, 4, 4};
+  static const u8 iValue[] =  {1, 0, 0, 0, 1, 1, 2};
+  int i, n;
+  if( isdigit(*z) ){
+    return atoi(z);
+  }
+  n = strlen(z);
+  for(i=0; i<sizeof(iLength); i++){
+    if( iLength[i]==n && sqlite3StrNICmp(&zText[iOffset[i]],z,n)==0 ){
+      return iValue[i];
+    }
+  }
+  return 1;
+}
+
+/*
+** Interpret the given string as a boolean value.
+*/
+static int getBoolean(const char *z){
+  return getSafetyLevel(z)&1;
+}
+
+/*
+** Interpret the given string as a locking mode value.
+*/
+static int getLockingMode(const char *z){
+  if( z ){
+    if( 0==sqlite3StrICmp(z, "exclusive") ) return PAGER_LOCKINGMODE_EXCLUSIVE;
+    if( 0==sqlite3StrICmp(z, "normal") ) return PAGER_LOCKINGMODE_NORMAL;
+  }
+  return PAGER_LOCKINGMODE_QUERY;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Interpret the given string as an auto-vacuum mode value.
+**
+** The following strings, "none", "full" and "incremental" are 
+** acceptable, as are their numeric equivalents: 0, 1 and 2 respectively.
+*/
+static int getAutoVacuum(const char *z){
+  int i;
+  if( 0==sqlite3StrICmp(z, "none") ) return BTREE_AUTOVACUUM_NONE;
+  if( 0==sqlite3StrICmp(z, "full") ) return BTREE_AUTOVACUUM_FULL;
+  if( 0==sqlite3StrICmp(z, "incremental") ) return BTREE_AUTOVACUUM_INCR;
+  i = atoi(z);
+  return ((i>=0&&i<=2)?i:0);
+}
+#endif /* ifndef SQLITE_OMIT_AUTOVACUUM */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Interpret the given string as a temp db location. Return 1 for file
+** backed temporary databases, 2 for the Red-Black tree in memory database
+** and 0 to use the compile-time default.
+*/
+static int getTempStore(const char *z){
+  if( z[0]>='0' && z[0]<='2' ){
+    return z[0] - '0';
+  }else if( sqlite3StrICmp(z, "file")==0 ){
+    return 1;
+  }else if( sqlite3StrICmp(z, "memory")==0 ){
+    return 2;
+  }else{
+    return 0;
+  }
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Invalidate temp storage, either when the temp storage is changed
+** from default, or when 'file' and the temp_store_directory has changed
+*/
+static int invalidateTempStorage(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt!=0 ){
+    if( !db->autoCommit ){
+      sqlite3ErrorMsg(pParse, "temporary storage cannot be changed "
+        "from within a transaction");
+      return SQLITE_ERROR;
+    }
+    sqlite3BtreeClose(db->aDb[1].pBt);
+    db->aDb[1].pBt = 0;
+    sqlite3ResetInternalSchema(db, 0);
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** If the TEMP database is open, close it and mark the database schema
+** as needing reloading.  This must be done when using the TEMP_STORE
+** or DEFAULT_TEMP_STORE pragmas.
+*/
+static int changeTempStorage(Parse *pParse, const char *zStorageType){
+  int ts = getTempStore(zStorageType);
+  sqlite3 *db = pParse->db;
+  if( db->temp_store==ts ) return SQLITE_OK;
+  if( invalidateTempStorage( pParse ) != SQLITE_OK ){
+    return SQLITE_ERROR;
+  }
+  db->temp_store = ts;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+/*
+** Generate code to return a single integer value.
+*/
+static void returnSingleInt(Parse *pParse, const char *zLabel, int value){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int mem = ++pParse->nMem;
+  sqlite3VdbeAddOp2(v, OP_Integer, value, mem);
+  if( pParse->explain==0 ){
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLabel, P4_STATIC);
+  }
+  sqlite3VdbeAddOp2(v, OP_ResultRow, mem, 1);
+}
+
+#ifndef SQLITE_OMIT_FLAG_PRAGMAS
+/*
+** Check to see if zRight and zLeft refer to a pragma that queries
+** or changes one of the flags in db->flags.  Return 1 if so and 0 if not.
+** Also, implement the pragma.
+*/
+static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
+  static const struct sPragmaType {
+    const char *zName;  /* Name of the pragma */
+    int mask;           /* Mask for the db->flags value */
+  } aPragma[] = {
+    { "full_column_names",        SQLITE_FullColNames  },
+    { "short_column_names",       SQLITE_ShortColNames },
+    { "count_changes",            SQLITE_CountRows     },
+    { "empty_result_callbacks",   SQLITE_NullCallback  },
+    { "legacy_file_format",       SQLITE_LegacyFileFmt },
+    { "fullfsync",                SQLITE_FullFSync     },
+#ifdef SQLITE_DEBUG
+    { "sql_trace",                SQLITE_SqlTrace      },
+    { "vdbe_listing",             SQLITE_VdbeListing   },
+    { "vdbe_trace",               SQLITE_VdbeTrace     },
+#endif
+#ifndef SQLITE_OMIT_CHECK
+    { "ignore_check_constraints", SQLITE_IgnoreChecks  },
+#endif
+    /* The following is VERY experimental */
+    { "writable_schema",          SQLITE_WriteSchema|SQLITE_RecoveryMode },
+    { "omit_readlock",            SQLITE_NoReadlock    },
+
+    /* TODO: Maybe it shouldn't be possible to change the ReadUncommitted
+    ** flag if there are any active statements. */
+    { "read_uncommitted",         SQLITE_ReadUncommitted },
+  };
+  int i;
+  const struct sPragmaType *p;
+  for(i=0, p=aPragma; i<sizeof(aPragma)/sizeof(aPragma[0]); i++, p++){
+    if( sqlite3StrICmp(zLeft, p->zName)==0 ){
+      sqlite3 *db = pParse->db;
+      Vdbe *v;
+      v = sqlite3GetVdbe(pParse);
+      if( v ){
+        if( zRight==0 ){
+          returnSingleInt(pParse, p->zName, (db->flags & p->mask)!=0 );
+        }else{
+          if( getBoolean(zRight) ){
+            db->flags |= p->mask;
+          }else{
+            db->flags &= ~p->mask;
+          }
+
+          /* Many of the flag-pragmas modify the code generated by the SQL 
+          ** compiler (eg. count_changes). So add an opcode to expire all
+          ** compiled SQL statements after modifying a pragma value.
+          */
+          sqlite3VdbeAddOp2(v, OP_Expire, 0, 0);
+        }
+      }
+
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_FLAG_PRAGMAS */
+
+/*
+** Process a pragma statement.  
+**
+** Pragmas are of this form:
+**
+**      PRAGMA [database.]id [= value]
+**
+** The identifier might also be a string.  The value is a string, and
+** identifier, or a number.  If minusFlag is true, then the value is
+** a number that was preceded by a minus sign.
+**
+** If the left side is "database.id" then pId1 is the database name
+** and pId2 is the id.  If the left side is just "id" then pId1 is the
+** id and pId2 is any empty string.
+*/
+SQLITE_PRIVATE void sqlite3Pragma(
+  Parse *pParse, 
+  Token *pId1,        /* First part of [database.]id field */
+  Token *pId2,        /* Second part of [database.]id field, or NULL */
+  Token *pValue,      /* Token for <value>, or NULL */
+  int minusFlag       /* True if a '-' sign preceded <value> */
+){
+  char *zLeft = 0;       /* Nul-terminated UTF-8 string <id> */
+  char *zRight = 0;      /* Nul-terminated UTF-8 string <value>, or NULL */
+  const char *zDb = 0;   /* The database name */
+  Token *pId;            /* Pointer to <id> token */
+  int iDb;               /* Database index for <database> */
+  sqlite3 *db = pParse->db;
+  Db *pDb;
+  Vdbe *v = pParse->pVdbe = sqlite3VdbeCreate(db);
+  if( v==0 ) return;
+  pParse->nMem = 2;
+
+  /* Interpret the [database.] part of the pragma statement. iDb is the
+  ** index of the database this pragma is being applied to in db.aDb[]. */
+  iDb = sqlite3TwoPartName(pParse, pId1, pId2, &pId);
+  if( iDb<0 ) return;
+  pDb = &db->aDb[iDb];
+
+  /* If the temp database has been explicitly named as part of the 
+  ** pragma, make sure it is open. 
+  */
+  if( iDb==1 && sqlite3OpenTempDatabase(pParse) ){
+    return;
+  }
+
+  zLeft = sqlite3NameFromToken(db, pId);
+  if( !zLeft ) return;
+  if( minusFlag ){
+    zRight = sqlite3MPrintf(db, "-%T", pValue);
+  }else{
+    zRight = sqlite3NameFromToken(db, pValue);
+  }
+
+  zDb = ((iDb>0)?pDb->zName:0);
+  if( sqlite3AuthCheck(pParse, SQLITE_PRAGMA, zLeft, zRight, zDb) ){
+    goto pragma_out;
+  }
+ 
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+  /*
+  **  PRAGMA [database.]default_cache_size
+  **  PRAGMA [database.]default_cache_size=N
+  **
+  ** The first form reports the current persistent setting for the
+  ** page cache size.  The value returned is the maximum number of
+  ** pages in the page cache.  The second form sets both the current
+  ** page cache size value and the persistent page cache size value
+  ** stored in the database file.
+  **
+  ** The default cache size is stored in meta-value 2 of page 1 of the
+  ** database file.  The cache size is actually the absolute value of
+  ** this memory location.  The sign of meta-value 2 determines the
+  ** synchronous setting.  A negative value means synchronous is off
+  ** and a positive value means synchronous is on.
+  */
+  if( sqlite3StrICmp(zLeft,"default_cache_size")==0 ){
+    static const VdbeOpList getCacheSize[] = {
+      { OP_ReadCookie,  0, 1,        2},  /* 0 */
+      { OP_IfPos,       1, 6,        0},
+      { OP_Integer,     0, 2,        0},
+      { OP_Subtract,    1, 2,        1},
+      { OP_IfPos,       1, 6,        0},
+      { OP_Integer,     0, 1,        0},  /* 5 */
+      { OP_ResultRow,   1, 1,        0},
+    };
+    int addr;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    sqlite3VdbeUsesBtree(v, iDb);
+    if( !zRight ){
+      sqlite3VdbeSetNumCols(v, 1);
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "cache_size", P4_STATIC);
+      pParse->nMem += 2;
+      addr = sqlite3VdbeAddOpList(v, ArraySize(getCacheSize), getCacheSize);
+      sqlite3VdbeChangeP1(v, addr, iDb);
+      sqlite3VdbeChangeP1(v, addr+5, SQLITE_DEFAULT_CACHE_SIZE);
+    }else{
+      int size = atoi(zRight);
+      if( size<0 ) size = -size;
+      sqlite3BeginWriteOperation(pParse, 0, iDb);
+      sqlite3VdbeAddOp2(v, OP_Integer, size, 1);
+      sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, 2, 2);
+      addr = sqlite3VdbeAddOp2(v, OP_IfPos, 2, 0);
+      sqlite3VdbeAddOp2(v, OP_Integer, -size, 1);
+      sqlite3VdbeJumpHere(v, addr);
+      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 2, 1);
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+  }else
+
+  /*
+  **  PRAGMA [database.]page_size
+  **  PRAGMA [database.]page_size=N
+  **
+  ** The first form reports the current setting for the
+  ** database page size in bytes.  The second form sets the
+  ** database page size value.  The value can only be set if
+  ** the database has not yet been created.
+  */
+  if( sqlite3StrICmp(zLeft,"page_size")==0 ){
+    Btree *pBt = pDb->pBt;
+    if( !zRight ){
+      int size = pBt ? sqlite3BtreeGetPageSize(pBt) : 0;
+      returnSingleInt(pParse, "page_size", size);
+    }else{
+      /* Malloc may fail when setting the page-size, as there is an internal
+      ** buffer that the pager module resizes using sqlite3_realloc().
+      */
+      db->nextPagesize = atoi(zRight);
+      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, -1) ){
+        db->mallocFailed = 1;
+      }
+    }
+  }else
+
+  /*
+  **  PRAGMA [database.]max_page_count
+  **  PRAGMA [database.]max_page_count=N
+  **
+  ** The first form reports the current setting for the
+  ** maximum number of pages in the database file.  The 
+  ** second form attempts to change this setting.  Both
+  ** forms return the current setting.
+  */
+  if( sqlite3StrICmp(zLeft,"max_page_count")==0 ){
+    Btree *pBt = pDb->pBt;
+    int newMax = 0;
+    if( zRight ){
+      newMax = atoi(zRight);
+    }
+    if( pBt ){
+      newMax = sqlite3BtreeMaxPageCount(pBt, newMax);
+    }
+    returnSingleInt(pParse, "max_page_count", newMax);
+  }else
+
+  /*
+  **  PRAGMA [database.]locking_mode
+  **  PRAGMA [database.]locking_mode = (normal|exclusive)
+  */
+  if( sqlite3StrICmp(zLeft,"locking_mode")==0 ){
+    const char *zRet = "normal";
+    int eMode = getLockingMode(zRight);
+
+    if( pId2->n==0 && eMode==PAGER_LOCKINGMODE_QUERY ){
+      /* Simple "PRAGMA locking_mode;" statement. This is a query for
+      ** the current default locking mode (which may be different to
+      ** the locking-mode of the main database).
+      */
+      eMode = db->dfltLockMode;
+    }else{
+      Pager *pPager;
+      if( pId2->n==0 ){
+        /* This indicates that no database name was specified as part
+        ** of the PRAGMA command. In this case the locking-mode must be
+        ** set on all attached databases, as well as the main db file.
+        **
+        ** Also, the sqlite3.dfltLockMode variable is set so that
+        ** any subsequently attached databases also use the specified
+        ** locking mode.
+        */
+        int ii;
+        assert(pDb==&db->aDb[0]);
+        for(ii=2; ii<db->nDb; ii++){
+          pPager = sqlite3BtreePager(db->aDb[ii].pBt);
+          sqlite3PagerLockingMode(pPager, eMode);
+        }
+        db->dfltLockMode = eMode;
+      }
+      pPager = sqlite3BtreePager(pDb->pBt);
+      eMode = sqlite3PagerLockingMode(pPager, eMode);
+    }
+
+    assert(eMode==PAGER_LOCKINGMODE_NORMAL||eMode==PAGER_LOCKINGMODE_EXCLUSIVE);
+    if( eMode==PAGER_LOCKINGMODE_EXCLUSIVE ){
+      zRet = "exclusive";
+    }
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "locking_mode", P4_STATIC);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, zRet, 0);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+  }else
+
+  /*
+  **  PRAGMA [database.]journal_mode
+  **  PRAGMA [database.]journal_mode = (delete|persist|off)
+  */
+  if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
+    int eMode;
+    static const char *azModeName[] = {"delete", "persist", "off"};
+
+    if( zRight==0 ){
+      eMode = PAGER_JOURNALMODE_QUERY;
+    }else{
+      int n = strlen(zRight);
+      eMode = 2;
+      while( eMode>=0 && sqlite3StrNICmp(zRight, azModeName[eMode], n)!=0 ){
+        eMode--;
+      }
+    }
+    if( pId2->n==0 && eMode==PAGER_JOURNALMODE_QUERY ){
+      /* Simple "PRAGMA persistent_journal;" statement. This is a query for
+      ** the current default journal mode (which may be different to
+      ** the journal-mode of the main database).
+      */
+      eMode = db->dfltJournalMode;
+    }else{
+      Pager *pPager;
+      if( pId2->n==0 ){
+        /* This indicates that no database name was specified as part
+        ** of the PRAGMA command. In this case the journal-mode must be
+        ** set on all attached databases, as well as the main db file.
+        **
+        ** Also, the sqlite3.dfltJournalMode variable is set so that
+        ** any subsequently attached databases also use the specified
+        ** journal mode.
+        */
+        int ii;
+        assert(pDb==&db->aDb[0]);
+        for(ii=1; ii<db->nDb; ii++){
+          if( db->aDb[ii].pBt ){
+            pPager = sqlite3BtreePager(db->aDb[ii].pBt);
+            sqlite3PagerJournalMode(pPager, eMode);
+          }
+        }
+        db->dfltJournalMode = eMode;
+      }
+      pPager = sqlite3BtreePager(pDb->pBt);
+      eMode = sqlite3PagerJournalMode(pPager, eMode);
+    }
+    assert( eMode==PAGER_JOURNALMODE_DELETE
+              || eMode==PAGER_JOURNALMODE_PERSIST
+              || eMode==PAGER_JOURNALMODE_OFF );
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", P4_STATIC);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, 
+           azModeName[eMode], P4_STATIC);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+  }else
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+  /*
+  **  PRAGMA [database.]auto_vacuum
+  **  PRAGMA [database.]auto_vacuum=N
+  **
+  ** Get or set the (boolean) value of the database 'auto-vacuum' parameter.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( sqlite3StrICmp(zLeft,"auto_vacuum")==0 ){
+    Btree *pBt = pDb->pBt;
+    if( sqlite3ReadSchema(pParse) ){
+      goto pragma_out;
+    }
+    if( !zRight ){
+      int auto_vacuum = 
+          pBt ? sqlite3BtreeGetAutoVacuum(pBt) : SQLITE_DEFAULT_AUTOVACUUM;
+      returnSingleInt(pParse, "auto_vacuum", auto_vacuum);
+    }else{
+      int eAuto = getAutoVacuum(zRight);
+      db->nextAutovac = eAuto;
+      if( eAuto>=0 ){
+        /* Call SetAutoVacuum() to set initialize the internal auto and
+        ** incr-vacuum flags. This is required in case this connection
+        ** creates the database file. It is important that it is created
+        ** as an auto-vacuum capable db.
+        */
+        int rc = sqlite3BtreeSetAutoVacuum(pBt, eAuto);
+        if( rc==SQLITE_OK && (eAuto==1 || eAuto==2) ){
+          /* When setting the auto_vacuum mode to either "full" or 
+          ** "incremental", write the value of meta[6] in the database
+          ** file. Before writing to meta[6], check that meta[3] indicates
+          ** that this really is an auto-vacuum capable database.
+          */
+          static const VdbeOpList setMeta6[] = {
+            { OP_Transaction,    0,               1,        0},    /* 0 */
+            { OP_ReadCookie,     0,               1,        3},    /* 1 */
+            { OP_If,             1,               0,        0},    /* 2 */
+            { OP_Halt,           SQLITE_OK,       OE_Abort, 0},    /* 3 */
+            { OP_Integer,        0,               1,        0},    /* 4 */
+            { OP_SetCookie,      0,               6,        1},    /* 5 */
+          };
+          int iAddr;
+          iAddr = sqlite3VdbeAddOpList(v, ArraySize(setMeta6), setMeta6);
+          sqlite3VdbeChangeP1(v, iAddr, iDb);
+          sqlite3VdbeChangeP1(v, iAddr+1, iDb);
+          sqlite3VdbeChangeP2(v, iAddr+2, iAddr+4);
+          sqlite3VdbeChangeP1(v, iAddr+4, eAuto-1);
+          sqlite3VdbeChangeP1(v, iAddr+5, iDb);
+          sqlite3VdbeUsesBtree(v, iDb);
+        }
+      }
+    }
+  }else
+#endif
+
+  /*
+  **  PRAGMA [database.]incremental_vacuum(N)
+  **
+  ** Do N steps of incremental vacuuming on a database.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( sqlite3StrICmp(zLeft,"incremental_vacuum")==0 ){
+    int iLimit, addr;
+    if( sqlite3ReadSchema(pParse) ){
+      goto pragma_out;
+    }
+    if( zRight==0 || !sqlite3GetInt32(zRight, &iLimit) || iLimit<=0 ){
+      iLimit = 0x7fffffff;
+    }
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3VdbeAddOp2(v, OP_Integer, iLimit, 1);
+    addr = sqlite3VdbeAddOp1(v, OP_IncrVacuum, iDb);
+    sqlite3VdbeAddOp1(v, OP_ResultRow, 1);
+    sqlite3VdbeAddOp2(v, OP_AddImm, 1, -1);
+    sqlite3VdbeAddOp2(v, OP_IfPos, 1, addr);
+    sqlite3VdbeJumpHere(v, addr);
+  }else
+#endif
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+  /*
+  **  PRAGMA [database.]cache_size
+  **  PRAGMA [database.]cache_size=N
+  **
+  ** The first form reports the current local setting for the
+  ** page cache size.  The local setting can be different from
+  ** the persistent cache size value that is stored in the database
+  ** file itself.  The value returned is the maximum number of
+  ** pages in the page cache.  The second form sets the local
+  ** page cache size value.  It does not change the persistent
+  ** cache size stored on the disk so the cache size will revert
+  ** to its default value when the database is closed and reopened.
+  ** N should be a positive integer.
+  */
+  if( sqlite3StrICmp(zLeft,"cache_size")==0 ){
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    if( !zRight ){
+      returnSingleInt(pParse, "cache_size", pDb->pSchema->cache_size);
+    }else{
+      int size = atoi(zRight);
+      if( size<0 ) size = -size;
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+  }else
+
+  /*
+  **   PRAGMA temp_store
+  **   PRAGMA temp_store = "default"|"memory"|"file"
+  **
+  ** Return or set the local value of the temp_store flag.  Changing
+  ** the local value does not make changes to the disk file and the default
+  ** value will be restored the next time the database is opened.
+  **
+  ** Note that it is possible for the library compile-time options to
+  ** override this setting
+  */
+  if( sqlite3StrICmp(zLeft, "temp_store")==0 ){
+    if( !zRight ){
+      returnSingleInt(pParse, "temp_store", db->temp_store);
+    }else{
+      changeTempStorage(pParse, zRight);
+    }
+  }else
+
+  /*
+  **   PRAGMA temp_store_directory
+  **   PRAGMA temp_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the temp_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for temporary files.
+  ** Setting to a null string reverts to the default temporary directory search.
+  ** If temporary directory is changed, then invalidateTempStorage.
+  **
+  */
+  if( sqlite3StrICmp(zLeft, "temp_store_directory")==0 ){
+    if( !zRight ){
+      if( sqlite3_temp_directory ){
+        sqlite3VdbeSetNumCols(v, 1);
+        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, 
+            "temp_store_directory", P4_STATIC);
+        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, sqlite3_temp_directory, 0);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+      }
+    }else{
+      if( zRight[0] 
+       && sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE)==0 
+      ){
+        sqlite3ErrorMsg(pParse, "not a writable directory");
+        goto pragma_out;
+      }
+      if( TEMP_STORE==0
+       || (TEMP_STORE==1 && db->temp_store<=1)
+       || (TEMP_STORE==2 && db->temp_store==1)
+      ){
+        invalidateTempStorage(pParse);
+      }
+      sqlite3_free(sqlite3_temp_directory);
+      if( zRight[0] ){
+        sqlite3_temp_directory = zRight;
+        zRight = 0;
+      }else{
+        sqlite3_temp_directory = 0;
+      }
+    }
+  }else
+
+  /*
+  **   PRAGMA [database.]synchronous
+  **   PRAGMA [database.]synchronous=OFF|ON|NORMAL|FULL
+  **
+  ** Return or set the local value of the synchronous flag.  Changing
+  ** the local value does not make changes to the disk file and the
+  ** default value will be restored the next time the database is
+  ** opened.
+  */
+  if( sqlite3StrICmp(zLeft,"synchronous")==0 ){
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    if( !zRight ){
+      returnSingleInt(pParse, "synchronous", pDb->safety_level-1);
+    }else{
+      if( !db->autoCommit ){
+        sqlite3ErrorMsg(pParse, 
+            "Safety level may not be changed inside a transaction");
+      }else{
+        pDb->safety_level = getSafetyLevel(zRight)+1;
+      }
+    }
+  }else
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FLAG_PRAGMAS
+  if( flagPragma(pParse, zLeft, zRight) ){
+    /* The flagPragma() subroutine also generates any necessary code
+    ** there is nothing more to do here */
+  }else
+#endif /* SQLITE_OMIT_FLAG_PRAGMAS */
+
+#ifndef SQLITE_OMIT_SCHEMA_PRAGMAS
+  /*
+  **   PRAGMA table_info(<table>)
+  **
+  ** Return a single row for each column of the named table. The columns of
+  ** the returned data set are:
+  **
+  ** cid:        Column id (numbered from left to right, starting at 0)
+  ** name:       Column name
+  ** type:       Column declaration type.
+  ** notnull:    True if 'NOT NULL' is part of column declaration
+  ** dflt_value: The default value for the column, if any.
+  */
+  if( sqlite3StrICmp(zLeft, "table_info")==0 && zRight ){
+    Table *pTab;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab ){
+      int i;
+      int nHidden = 0;
+      Column *pCol;
+      sqlite3VdbeSetNumCols(v, 6);
+      pParse->nMem = 6;
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "cid", P4_STATIC);
+      sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "name", P4_STATIC);
+      sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "type", P4_STATIC);
+      sqlite3VdbeSetColName(v, 3, COLNAME_NAME, "notnull", P4_STATIC);
+      sqlite3VdbeSetColName(v, 4, COLNAME_NAME, "dflt_value", P4_STATIC);
+      sqlite3VdbeSetColName(v, 5, COLNAME_NAME, "pk", P4_STATIC);
+      sqlite3ViewGetColumnNames(pParse, pTab);
+      for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
+        const Token *pDflt;
+        if( IsHiddenColumn(pCol) ){
+          nHidden++;
+          continue;
+        }
+        sqlite3VdbeAddOp2(v, OP_Integer, i-nHidden, 1);
+        sqlite3VdbeAddOp4(v, OP_String8, 0, 2, 0, pCol->zName, 0);
+        sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
+           pCol->zType ? pCol->zType : "", 0);
+        sqlite3VdbeAddOp2(v, OP_Integer, pCol->notNull, 4);
+        if( pCol->pDflt && (pDflt = &pCol->pDflt->span)->z ){
+          sqlite3VdbeAddOp4(v, OP_String8, 0, 5, 0, (char*)pDflt->z, pDflt->n);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Null, 0, 5);
+        }
+        sqlite3VdbeAddOp2(v, OP_Integer, pCol->isPrimKey, 6);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 6);
+      }
+    }
+  }else
+
+  if( sqlite3StrICmp(zLeft, "index_info")==0 && zRight ){
+    Index *pIdx;
+    Table *pTab;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    pIdx = sqlite3FindIndex(db, zRight, zDb);
+    if( pIdx ){
+      int i;
+      pTab = pIdx->pTable;
+      sqlite3VdbeSetNumCols(v, 3);
+      pParse->nMem = 3;
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "seqno", P4_STATIC);
+      sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "cid", P4_STATIC);
+      sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "name", P4_STATIC);
+      for(i=0; i<pIdx->nColumn; i++){
+        int cnum = pIdx->aiColumn[i];
+        sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
+        sqlite3VdbeAddOp2(v, OP_Integer, cnum, 2);
+        assert( pTab->nCol>cnum );
+        sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, pTab->aCol[cnum].zName, 0);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+      }
+    }
+  }else
+
+  if( sqlite3StrICmp(zLeft, "index_list")==0 && zRight ){
+    Index *pIdx;
+    Table *pTab;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab ){
+      v = sqlite3GetVdbe(pParse);
+      pIdx = pTab->pIndex;
+      if( pIdx ){
+        int i = 0; 
+        sqlite3VdbeSetNumCols(v, 3);
+        pParse->nMem = 3;
+        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "seq", P4_STATIC);
+        sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "name", P4_STATIC);
+        sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "unique", P4_STATIC);
+        while(pIdx){
+          sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
+          sqlite3VdbeAddOp4(v, OP_String8, 0, 2, 0, pIdx->zName, 0);
+          sqlite3VdbeAddOp2(v, OP_Integer, pIdx->onError!=OE_None, 3);
+          sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+          ++i;
+          pIdx = pIdx->pNext;
+        }
+      }
+    }
+  }else
+
+  if( sqlite3StrICmp(zLeft, "database_list")==0 ){
+    int i;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    sqlite3VdbeSetNumCols(v, 3);
+    pParse->nMem = 3;
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "seq", P4_STATIC);
+    sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "name", P4_STATIC);
+    sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "file", P4_STATIC);
+    for(i=0; i<db->nDb; i++){
+      if( db->aDb[i].pBt==0 ) continue;
+      assert( db->aDb[i].zName!=0 );
+      sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 2, 0, db->aDb[i].zName, 0);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
+           sqlite3BtreeGetFilename(db->aDb[i].pBt), 0);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+    }
+  }else
+
+  if( sqlite3StrICmp(zLeft, "collation_list")==0 ){
+    int i = 0;
+    HashElem *p;
+    sqlite3VdbeSetNumCols(v, 2);
+    pParse->nMem = 2;
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "seq", P4_STATIC);
+    sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "name", P4_STATIC);
+    for(p=sqliteHashFirst(&db->aCollSeq); p; p=sqliteHashNext(p)){
+      CollSeq *pColl = (CollSeq *)sqliteHashData(p);
+      sqlite3VdbeAddOp2(v, OP_Integer, i++, 1);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 2, 0, pColl->zName, 0);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 2);
+    }
+  }else
+#endif /* SQLITE_OMIT_SCHEMA_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  if( sqlite3StrICmp(zLeft, "foreign_key_list")==0 && zRight ){
+    FKey *pFK;
+    Table *pTab;
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab ){
+      v = sqlite3GetVdbe(pParse);
+      pFK = pTab->pFKey;
+      if( pFK ){
+        int i = 0; 
+        sqlite3VdbeSetNumCols(v, 5);
+        pParse->nMem = 5;
+        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "id", P4_STATIC);
+        sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "seq", P4_STATIC);
+        sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "table", P4_STATIC);
+        sqlite3VdbeSetColName(v, 3, COLNAME_NAME, "from", P4_STATIC);
+        sqlite3VdbeSetColName(v, 4, COLNAME_NAME, "to", P4_STATIC);
+        while(pFK){
+          int j;
+          for(j=0; j<pFK->nCol; j++){
+            char *zCol = pFK->aCol[j].zCol;
+            sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
+            sqlite3VdbeAddOp2(v, OP_Integer, j, 2);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, pFK->zTo, 0);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 4, 0,
+                              pTab->aCol[pFK->aCol[j].iFrom].zName, 0);
+            sqlite3VdbeAddOp4(v, zCol ? OP_String8 : OP_Null, 0, 5, 0, zCol, 0);
+            sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 5);
+          }
+          ++i;
+          pFK = pFK->pNextFrom;
+        }
+      }
+    }
+  }else
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+
+#ifndef NDEBUG
+  if( sqlite3StrICmp(zLeft, "parser_trace")==0 ){
+    if( zRight ){
+      if( getBoolean(zRight) ){
+        sqlite3ParserTrace(stderr, "parser: ");
+      }else{
+        sqlite3ParserTrace(0, 0);
+      }
+    }
+  }else
+#endif
+
+  /* Reinstall the LIKE and GLOB functions.  The variant of LIKE
+  ** used will be case sensitive or not depending on the RHS.
+  */
+  if( sqlite3StrICmp(zLeft, "case_sensitive_like")==0 ){
+    if( zRight ){
+      sqlite3RegisterLikeFunctions(db, getBoolean(zRight));
+    }
+  }else
+
+#ifndef SQLITE_INTEGRITY_CHECK_ERROR_MAX
+# define SQLITE_INTEGRITY_CHECK_ERROR_MAX 100
+#endif
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+  /* Pragma "quick_check" is an experimental reduced version of 
+  ** integrity_check designed to detect most database corruption
+  ** without most of the overhead of a full integrity-check.
+  */
+  if( sqlite3StrICmp(zLeft, "integrity_check")==0
+   || sqlite3StrICmp(zLeft, "quick_check")==0 
+  ){
+    int i, j, addr, mxErr;
+
+    /* Code that appears at the end of the integrity check.  If no error
+    ** messages have been generated, output OK.  Otherwise output the
+    ** error message
+    */
+    static const VdbeOpList endCode[] = {
+      { OP_AddImm,      1, 0,        0},    /* 0 */
+      { OP_IfNeg,       1, 0,        0},    /* 1 */
+      { OP_String8,     0, 3,        0},    /* 2 */
+      { OP_ResultRow,   3, 1,        0},
+    };
+
+    int isQuick = (zLeft[0]=='q');
+
+    /* Initialize the VDBE program */
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    pParse->nMem = 6;
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "integrity_check", P4_STATIC);
+
+    /* Set the maximum error count */
+    mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+    if( zRight ){
+      mxErr = atoi(zRight);
+      if( mxErr<=0 ){
+        mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_Integer, mxErr, 1);  /* reg[1] holds errors left */
+
+    /* Do an integrity check on each database file */
+    for(i=0; i<db->nDb; i++){
+      HashElem *x;
+      Hash *pTbls;
+      int cnt = 0;
+
+      if( OMIT_TEMPDB && i==1 ) continue;
+
+      sqlite3CodeVerifySchema(pParse, i);
+      addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1); /* Halt if out of errors */
+      sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
+      sqlite3VdbeJumpHere(v, addr);
+
+      /* Do an integrity check of the B-Tree
+      **
+      ** Begin by filling registers 2, 3, ... with the root pages numbers
+      ** for all tables and indices in the database.
+      */
+      pTbls = &db->aDb[i].pSchema->tblHash;
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        sqlite3VdbeAddOp2(v, OP_Integer, pTab->tnum, 2+cnt);
+        cnt++;
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          sqlite3VdbeAddOp2(v, OP_Integer, pIdx->tnum, 2+cnt);
+          cnt++;
+        }
+      }
+      if( cnt==0 ) continue;
+
+      /* Make sure sufficient number of registers have been allocated */
+      if( pParse->nMem < cnt+4 ){
+        pParse->nMem = cnt+4;
+      }
+
+      /* Do the b-tree integrity checks */
+      sqlite3VdbeAddOp3(v, OP_IntegrityCk, 2, cnt, 1);
+      sqlite3VdbeChangeP5(v, i);
+      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
+         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zName),
+         P4_DYNAMIC);
+      sqlite3VdbeAddOp2(v, OP_Move, 2, 4);
+      sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 2);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 2, 1);
+      sqlite3VdbeJumpHere(v, addr);
+
+      /* Make sure all the indices are constructed correctly.
+      */
+      for(x=sqliteHashFirst(pTbls); x && !isQuick; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        int loopTop;
+
+        if( pTab->pIndex==0 ) continue;
+        addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1);  /* Stop if out of errors */
+        sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
+        sqlite3VdbeJumpHere(v, addr);
+        sqlite3OpenTableAndIndices(pParse, pTab, 1, OP_OpenRead);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, 2);  /* reg(2) will count entries */
+        loopTop = sqlite3VdbeAddOp2(v, OP_Rewind, 1, 0);
+        sqlite3VdbeAddOp2(v, OP_AddImm, 2, 1);   /* increment entry count */
+        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+          int jmp2;
+          static const VdbeOpList idxErr[] = {
+            { OP_AddImm,      1, -1,  0},
+            { OP_String8,     0,  3,  0},    /* 1 */
+            { OP_Rowid,       1,  4,  0},
+            { OP_String8,     0,  5,  0},    /* 3 */
+            { OP_String8,     0,  6,  0},    /* 4 */
+            { OP_Concat,      4,  3,  3},
+            { OP_Concat,      5,  3,  3},
+            { OP_Concat,      6,  3,  3},
+            { OP_ResultRow,   3,  1,  0},
+            { OP_IfPos,       1,  0,  0},    /* 9 */
+            { OP_Halt,        0,  0,  0},
+          };
+          sqlite3GenerateIndexKey(pParse, pIdx, 1, 3, 1);
+          jmp2 = sqlite3VdbeAddOp3(v, OP_Found, j+2, 0, 3);
+          addr = sqlite3VdbeAddOpList(v, ArraySize(idxErr), idxErr);
+          sqlite3VdbeChangeP4(v, addr+1, "rowid ", P4_STATIC);
+          sqlite3VdbeChangeP4(v, addr+3, " missing from index ", P4_STATIC);
+          sqlite3VdbeChangeP4(v, addr+4, pIdx->zName, P4_STATIC);
+          sqlite3VdbeJumpHere(v, addr+9);
+          sqlite3VdbeJumpHere(v, jmp2);
+        }
+        sqlite3VdbeAddOp2(v, OP_Next, 1, loopTop+1);
+        sqlite3VdbeJumpHere(v, loopTop);
+        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+          static const VdbeOpList cntIdx[] = {
+             { OP_Integer,      0,  3,  0},
+             { OP_Rewind,       0,  0,  0},  /* 1 */
+             { OP_AddImm,       3,  1,  0},
+             { OP_Next,         0,  0,  0},  /* 3 */
+             { OP_Eq,           2,  0,  3},  /* 4 */
+             { OP_AddImm,       1, -1,  0},
+             { OP_String8,      0,  2,  0},  /* 6 */
+             { OP_String8,      0,  3,  0},  /* 7 */
+             { OP_Concat,       3,  2,  2},
+             { OP_ResultRow,    2,  1,  0},
+          };
+          if( pIdx->tnum==0 ) continue;
+          addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1);
+          sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
+          sqlite3VdbeJumpHere(v, addr);
+          addr = sqlite3VdbeAddOpList(v, ArraySize(cntIdx), cntIdx);
+          sqlite3VdbeChangeP1(v, addr+1, j+2);
+          sqlite3VdbeChangeP2(v, addr+1, addr+4);
+          sqlite3VdbeChangeP1(v, addr+3, j+2);
+          sqlite3VdbeChangeP2(v, addr+3, addr+2);
+          sqlite3VdbeJumpHere(v, addr+4);
+          sqlite3VdbeChangeP4(v, addr+6, 
+                     "wrong # of entries in index ", P4_STATIC);
+          sqlite3VdbeChangeP4(v, addr+7, pIdx->zName, P4_STATIC);
+        }
+      } 
+    }
+    addr = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode);
+    sqlite3VdbeChangeP2(v, addr, -mxErr);
+    sqlite3VdbeJumpHere(v, addr+1);
+    sqlite3VdbeChangeP4(v, addr+2, "ok", P4_STATIC);
+  }else
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_UTF16
+  /*
+  **   PRAGMA encoding
+  **   PRAGMA encoding = "utf-8"|"utf-16"|"utf-16le"|"utf-16be"
+  **
+  ** In its first form, this pragma returns the encoding of the main
+  ** database. If the database is not initialized, it is initialized now.
+  **
+  ** The second form of this pragma is a no-op if the main database file
+  ** has not already been initialized. In this case it sets the default
+  ** encoding that will be used for the main database file if a new file
+  ** is created. If an existing main database file is opened, then the
+  ** default text encoding for the existing database is used.
+  ** 
+  ** In all cases new databases created using the ATTACH command are
+  ** created to use the same default text encoding as the main database. If
+  ** the main database has not been initialized and/or created when ATTACH
+  ** is executed, this is done before the ATTACH operation.
+  **
+  ** In the second form this pragma sets the text encoding to be used in
+  ** new database files created using this database handle. It is only
+  ** useful if invoked immediately after the main database i
+  */
+  if( sqlite3StrICmp(zLeft, "encoding")==0 ){
+    static const struct EncName {
+      char *zName;
+      u8 enc;
+    } encnames[] = {
+      { "UTF-8",    SQLITE_UTF8        },
+      { "UTF8",     SQLITE_UTF8        },
+      { "UTF-16le", SQLITE_UTF16LE     },
+      { "UTF16le",  SQLITE_UTF16LE     },
+      { "UTF-16be", SQLITE_UTF16BE     },
+      { "UTF16be",  SQLITE_UTF16BE     },
+      { "UTF-16",   0                  }, /* SQLITE_UTF16NATIVE */
+      { "UTF16",    0                  }, /* SQLITE_UTF16NATIVE */
+      { 0, 0 }
+    };
+    const struct EncName *pEnc;
+    if( !zRight ){    /* "PRAGMA encoding" */
+      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+      sqlite3VdbeSetNumCols(v, 1);
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "encoding", P4_STATIC);
+      sqlite3VdbeAddOp2(v, OP_String8, 0, 1);
+      for(pEnc=&encnames[0]; pEnc->zName; pEnc++){
+        if( pEnc->enc==ENC(pParse->db) ){
+          sqlite3VdbeChangeP4(v, -1, pEnc->zName, P4_STATIC);
+          break;
+        }
+      }
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    }else{                        /* "PRAGMA encoding = XXX" */
+      /* Only change the value of sqlite.enc if the database handle is not
+      ** initialized. If the main database exists, the new sqlite.enc value
+      ** will be overwritten when the schema is next loaded. If it does not
+      ** already exists, it will be created to use the new encoding value.
+      */
+      if( 
+        !(DbHasProperty(db, 0, DB_SchemaLoaded)) || 
+        DbHasProperty(db, 0, DB_Empty) 
+      ){
+        for(pEnc=&encnames[0]; pEnc->zName; pEnc++){
+          if( 0==sqlite3StrICmp(zRight, pEnc->zName) ){
+            ENC(pParse->db) = pEnc->enc ? pEnc->enc : SQLITE_UTF16NATIVE;
+            break;
+          }
+        }
+        if( !pEnc->zName ){
+          sqlite3ErrorMsg(pParse, "unsupported encoding: %s", zRight);
+        }
+      }
+    }
+  }else
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  /*
+  **   PRAGMA [database.]schema_version
+  **   PRAGMA [database.]schema_version = <integer>
+  **
+  **   PRAGMA [database.]user_version
+  **   PRAGMA [database.]user_version = <integer>
+  **
+  ** The pragma's schema_version and user_version are used to set or get
+  ** the value of the schema-version and user-version, respectively. Both
+  ** the schema-version and the user-version are 32-bit signed integers
+  ** stored in the database header.
+  **
+  ** The schema-cookie is usually only manipulated internally by SQLite. It
+  ** is incremented by SQLite whenever the database schema is modified (by
+  ** creating or dropping a table or index). The schema version is used by
+  ** SQLite each time a query is executed to ensure that the internal cache
+  ** of the schema used when compiling the SQL query matches the schema of
+  ** the database against which the compiled query is actually executed.
+  ** Subverting this mechanism by using "PRAGMA schema_version" to modify
+  ** the schema-version is potentially dangerous and may lead to program
+  ** crashes or database corruption. Use with caution!
+  **
+  ** The user-version is not used internally by SQLite. It may be used by
+  ** applications for any purpose.
+  */
+  if( sqlite3StrICmp(zLeft, "schema_version")==0 
+   || sqlite3StrICmp(zLeft, "user_version")==0 
+   || sqlite3StrICmp(zLeft, "freelist_count")==0 
+  ){
+
+    int iCookie;   /* Cookie index. 0 for schema-cookie, 6 for user-cookie. */
+    sqlite3VdbeUsesBtree(v, iDb);
+    switch( zLeft[0] ){
+      case 's': case 'S':
+        iCookie = 0;
+        break;
+      case 'f': case 'F':
+        iCookie = 1;
+        iDb = (-1*(iDb+1));
+        assert(iDb<=0);
+        break;
+      default:
+        iCookie = 5;
+        break;
+    }
+
+    if( zRight && iDb>=0 ){
+      /* Write the specified cookie value */
+      static const VdbeOpList setCookie[] = {
+        { OP_Transaction,    0,  1,  0},    /* 0 */
+        { OP_Integer,        0,  1,  0},    /* 1 */
+        { OP_SetCookie,      0,  0,  1},    /* 2 */
+      };
+      int addr = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie);
+      sqlite3VdbeChangeP1(v, addr, iDb);
+      sqlite3VdbeChangeP1(v, addr+1, atoi(zRight));
+      sqlite3VdbeChangeP1(v, addr+2, iDb);
+      sqlite3VdbeChangeP2(v, addr+2, iCookie);
+    }else{
+      /* Read the specified cookie value */
+      static const VdbeOpList readCookie[] = {
+        { OP_ReadCookie,      0,  1,  0},    /* 0 */
+        { OP_ResultRow,       1,  1,  0}
+      };
+      int addr = sqlite3VdbeAddOpList(v, ArraySize(readCookie), readCookie);
+      sqlite3VdbeChangeP1(v, addr, iDb);
+      sqlite3VdbeChangeP3(v, addr, iCookie);
+      sqlite3VdbeSetNumCols(v, 1);
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLeft, P4_TRANSIENT);
+    }
+  }else
+#endif /* SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS */
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /*
+  ** Report the current state of file logs for all databases
+  */
+  if( sqlite3StrICmp(zLeft, "lock_status")==0 ){
+    static const char *const azLockName[] = {
+      "unlocked", "shared", "reserved", "pending", "exclusive"
+    };
+    int i;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+    sqlite3VdbeSetNumCols(v, 2);
+    pParse->nMem = 2;
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "database", P4_STATIC);
+    sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "status", P4_STATIC);
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt;
+      Pager *pPager;
+      const char *zState = "unknown";
+      int j;
+      if( db->aDb[i].zName==0 ) continue;
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, db->aDb[i].zName, P4_STATIC);
+      pBt = db->aDb[i].pBt;
+      if( pBt==0 || (pPager = sqlite3BtreePager(pBt))==0 ){
+        zState = "closed";
+      }else if( sqlite3_file_control(db, i ? db->aDb[i].zName : 0, 
+                                     SQLITE_FCNTL_LOCKSTATE, &j)==SQLITE_OK ){
+         zState = azLockName[j];
+      }
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 2, 0, zState, P4_STATIC);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 2);
+    }
+  }else
+#endif
+
+#ifdef SQLITE_SSE
+  /*
+  ** Check to see if the sqlite_statements table exists.  Create it
+  ** if it does not.
+  */
+  if( sqlite3StrICmp(zLeft, "create_sqlite_statement_table")==0 ){
+    extern int sqlite3CreateStatementsTable(Parse*);
+    sqlite3CreateStatementsTable(pParse);
+  }else
+#endif
+
+#if SQLITE_HAS_CODEC
+  if( sqlite3StrICmp(zLeft, "key")==0 ){
+    sqlite3_key(db, zRight, strlen(zRight));
+  }else
+#endif
+#if SQLITE_HAS_CODEC || defined(SQLITE_ENABLE_CEROD)
+  if( sqlite3StrICmp(zLeft, "activate_extensions")==0 ){
+#if SQLITE_HAS_CODEC
+    if( sqlite3StrNICmp(zRight, "see-", 4)==0 ){
+      extern void sqlite3_activate_see(const char*);
+      sqlite3_activate_see(&zRight[4]);
+    }
+#endif
+#ifdef SQLITE_ENABLE_CEROD
+    if( sqlite3StrNICmp(zRight, "cerod-", 6)==0 ){
+      extern void sqlite3_activate_cerod(const char*);
+      sqlite3_activate_cerod(&zRight[6]);
+    }
+#endif
+  }
+#endif
+
+  {}
+
+  if( v ){
+    /* Code an OP_Expire at the end of each PRAGMA program to cause
+    ** the VDBE implementing the pragma to expire. Most (all?) pragmas
+    ** are only valid for a single execution.
+    */
+    sqlite3VdbeAddOp2(v, OP_Expire, 1, 0);
+
+    /*
+    ** Reset the safety level, in case the fullfsync flag or synchronous
+    ** setting changed.
+    */
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+    if( db->autoCommit ){
+      sqlite3BtreeSetSafetyLevel(pDb->pBt, pDb->safety_level,
+                 (db->flags&SQLITE_FullFSync)!=0);
+    }
+#endif
+  }
+pragma_out:
+  sqlite3_free(zLeft);
+  sqlite3_free(zRight);
+}
+
+#endif /* SQLITE_OMIT_PRAGMA || SQLITE_OMIT_PARSER */
+
+/************** End of pragma.c **********************************************/
+/************** Begin file prepare.c *****************************************/
+/*
+** 2005 May 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_prepare()
+** interface, and routines that contribute to loading the database schema
+** from disk.
+**
+** $Id: prepare.c,v 1.83 2008/04/03 14:36:26 danielk1977 Exp $
+*/
+
+/*
+** Fill the InitData structure with an error message that indicates
+** that the database is corrupt.
+*/
+static void corruptSchema(
+  InitData *pData,     /* Initialization context */
+  const char *zObj,    /* Object being parsed at the point of error */
+  const char *zExtra   /* Error information */
+){
+  if( !pData->db->mallocFailed ){
+    if( zObj==0 ) zObj = "?";
+    sqlite3SetString(pData->pzErrMsg, "malformed database schema (",  zObj, ")",
+       zExtra!=0 && zExtra[0]!=0 ? " - " : (char*)0, zExtra, (char*)0);
+  }
+  pData->rc = SQLITE_CORRUPT;
+}
+
+/*
+** This is the callback routine for the code that initializes the
+** database.  See sqlite3Init() below for additional information.
+** This routine is also called from the OP_ParseSchema opcode of the VDBE.
+**
+** Each callback contains the following information:
+**
+**     argv[0] = name of thing being created
+**     argv[1] = root page number for table or index. 0 for trigger or view.
+**     argv[2] = SQL text for the CREATE statement.
+**
+*/
+SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
+  InitData *pData = (InitData*)pInit;
+  sqlite3 *db = pData->db;
+  int iDb = pData->iDb;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  pData->rc = SQLITE_OK;
+  DbClearProperty(db, iDb, DB_Empty);
+  if( db->mallocFailed ){
+    corruptSchema(pData, argv[0], 0);
+    return SQLITE_NOMEM;
+  }
+
+  assert( argc==3 );
+  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
+  if( argv[1]==0 ){
+    corruptSchema(pData, argv[0], 0);
+    return 1;
+  }
+  assert( iDb>=0 && iDb<db->nDb );
+  if( argv[2] && argv[2][0] ){
+    /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
+    ** But because db->init.busy is set to 1, no VDBE code is generated
+    ** or executed.  All the parser does is build the internal data
+    ** structures that describe the table, index, or view.
+    */
+    char *zErr;
+    int rc;
+    assert( db->init.busy );
+    db->init.iDb = iDb;
+    db->init.newTnum = atoi(argv[1]);
+    rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
+    db->init.iDb = 0;
+    assert( rc!=SQLITE_OK || zErr==0 );
+    if( SQLITE_OK!=rc ){
+      pData->rc = rc;
+      if( rc==SQLITE_NOMEM ){
+        db->mallocFailed = 1;
+      }else if( rc!=SQLITE_INTERRUPT ){
+        corruptSchema(pData, argv[0], zErr);
+      }
+      sqlite3_free(zErr);
+      return 1;
+    }
+  }else if( argv[0]==0 ){
+    corruptSchema(pData, 0, 0);
+  }else{
+    /* If the SQL column is blank it means this is an index that
+    ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
+    ** constraint for a CREATE TABLE.  The index should have already
+    ** been created when we processed the CREATE TABLE.  All we have
+    ** to do here is record the root page number for that index.
+    */
+    Index *pIndex;
+    pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zName);
+    if( pIndex==0 || pIndex->tnum!=0 ){
+      /* This can occur if there exists an index on a TEMP table which
+      ** has the same name as another index on a permanent index.  Since
+      ** the permanent table is hidden by the TEMP table, we can also
+      ** safely ignore the index on the permanent table.
+      */
+      /* Do Nothing */;
+    }else{
+      pIndex->tnum = atoi(argv[1]);
+    }
+  }
+  return 0;
+}
+
+/*
+** Attempt to read the database schema and initialize internal
+** data structures for a single database file.  The index of the
+** database file is given by iDb.  iDb==0 is used for the main
+** database.  iDb==1 should never be used.  iDb>=2 is used for
+** auxiliary databases.  Return one of the SQLITE_ error codes to
+** indicate success or failure.
+*/
+static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
+  int rc;
+  BtCursor *curMain;
+  int size;
+  Table *pTab;
+  Db *pDb;
+  char const *azArg[4];
+  int meta[10];
+  InitData initData;
+  char const *zMasterSchema;
+  char const *zMasterName = SCHEMA_TABLE(iDb);
+
+  /*
+  ** The master database table has a structure like this
+  */
+  static const char master_schema[] = 
+     "CREATE TABLE sqlite_master(\n"
+     "  type text,\n"
+     "  name text,\n"
+     "  tbl_name text,\n"
+     "  rootpage integer,\n"
+     "  sql text\n"
+     ")"
+  ;
+#ifndef SQLITE_OMIT_TEMPDB
+  static const char temp_master_schema[] = 
+     "CREATE TEMP TABLE sqlite_temp_master(\n"
+     "  type text,\n"
+     "  name text,\n"
+     "  tbl_name text,\n"
+     "  rootpage integer,\n"
+     "  sql text\n"
+     ")"
+  ;
+#else
+  #define temp_master_schema 0
+#endif
+
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+
+  /* zMasterSchema and zInitScript are set to point at the master schema
+  ** and initialisation script appropriate for the database being
+  ** initialised. zMasterName is the name of the master table.
+  */
+  if( !OMIT_TEMPDB && iDb==1 ){
+    zMasterSchema = temp_master_schema;
+  }else{
+    zMasterSchema = master_schema;
+  }
+  zMasterName = SCHEMA_TABLE(iDb);
+
+  /* Construct the schema tables.  */
+  azArg[0] = zMasterName;
+  azArg[1] = "1";
+  azArg[2] = zMasterSchema;
+  azArg[3] = 0;
+  initData.db = db;
+  initData.iDb = iDb;
+  initData.pzErrMsg = pzErrMsg;
+  (void)sqlite3SafetyOff(db);
+  rc = sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
+  (void)sqlite3SafetyOn(db);
+  if( rc ){
+    rc = initData.rc;
+    goto error_out;
+  }
+  pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
+  if( pTab ){
+    pTab->readOnly = 1;
+  }
+
+  /* Create a cursor to hold the database open
+  */
+  pDb = &db->aDb[iDb];
+  if( pDb->pBt==0 ){
+    if( !OMIT_TEMPDB && iDb==1 ){
+      DbSetProperty(db, 1, DB_SchemaLoaded);
+    }
+    return SQLITE_OK;
+  }
+  curMain = sqlite3MallocZero(sqlite3BtreeCursorSize());
+  if( !curMain ){
+    rc = SQLITE_NOMEM;
+    goto error_out;
+  }
+  sqlite3BtreeEnter(pDb->pBt);
+  rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, curMain);
+  if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
+    sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
+    goto leave_error_out;
+  }
+
+  /* Get the database meta information.
+  **
+  ** Meta values are as follows:
+  **    meta[0]   Schema cookie.  Changes with each schema change.
+  **    meta[1]   File format of schema layer.
+  **    meta[2]   Size of the page cache.
+  **    meta[3]   Use freelist if 0.  Autovacuum if greater than zero.
+  **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
+  **    meta[5]   The user cookie. Used by the application.
+  **    meta[6]   Incremental-vacuum flag.
+  **    meta[7]
+  **    meta[8]
+  **    meta[9]
+  **
+  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
+  ** the possible values of meta[4].
+  */
+  if( rc==SQLITE_OK ){
+    int i;
+    for(i=0; rc==SQLITE_OK && i<sizeof(meta)/sizeof(meta[0]); i++){
+      rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
+    }
+    if( rc ){
+      sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
+      goto leave_error_out;
+    }
+  }else{
+    memset(meta, 0, sizeof(meta));
+  }
+  pDb->pSchema->schema_cookie = meta[0];
+
+  /* If opening a non-empty database, check the text encoding. For the
+  ** main database, set sqlite3.enc to the encoding of the main database.
+  ** For an attached db, it is an error if the encoding is not the same
+  ** as sqlite3.enc.
+  */
+  if( meta[4] ){  /* text encoding */
+    if( iDb==0 ){
+      /* If opening the main database, set ENC(db). */
+      ENC(db) = (u8)meta[4];
+      db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
+    }else{
+      /* If opening an attached database, the encoding much match ENC(db) */
+      if( meta[4]!=ENC(db) ){
+        sqlite3SetString(pzErrMsg, "attached databases must use the same"
+            " text encoding as main database", (char*)0);
+        rc = SQLITE_ERROR;
+        goto leave_error_out;
+      }
+    }
+  }else{
+    DbSetProperty(db, iDb, DB_Empty);
+  }
+  pDb->pSchema->enc = ENC(db);
+
+  size = meta[2];
+  if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
+  if( size<0 ) size = -size;
+  pDb->pSchema->cache_size = size;
+  sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+
+  /*
+  ** file_format==1    Version 3.0.0.
+  ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
+  ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
+  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
+  */
+  pDb->pSchema->file_format = meta[1];
+  if( pDb->pSchema->file_format==0 ){
+    pDb->pSchema->file_format = 1;
+  }
+  if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
+    sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
+    rc = SQLITE_ERROR;
+    goto leave_error_out;
+  }
+
+  /* Ticket #2804:  When we open a database in the newer file format,
+  ** clear the legacy_file_format pragma flag so that a VACUUM will
+  ** not downgrade the database and thus invalidate any descending
+  ** indices that the user might have created.
+  */
+  if( iDb==0 && meta[1]>=4 ){
+    db->flags &= ~SQLITE_LegacyFileFmt;
+  }
+
+  /* Read the schema information out of the schema tables
+  */
+  assert( db->init.busy );
+  if( rc==SQLITE_EMPTY ){
+    /* For an empty database, there is nothing to read */
+    rc = SQLITE_OK;
+  }else{
+    char *zSql;
+    zSql = sqlite3MPrintf(db, 
+        "SELECT name, rootpage, sql FROM '%q'.%s",
+        db->aDb[iDb].zName, zMasterName);
+    (void)sqlite3SafetyOff(db);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
+      xAuth = db->xAuth;
+      db->xAuth = 0;
+#endif
+      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      db->xAuth = xAuth;
+    }
+#endif
+    if( rc==SQLITE_ABORT ) rc = initData.rc;
+    (void)sqlite3SafetyOn(db);
+    sqlite3_free(zSql);
+#ifndef SQLITE_OMIT_ANALYZE
+    if( rc==SQLITE_OK ){
+      sqlite3AnalysisLoad(db, iDb);
+    }
+#endif
+  }
+  if( db->mallocFailed ){
+    /* sqlite3SetString(pzErrMsg, "out of memory", (char*)0); */
+    rc = SQLITE_NOMEM;
+    sqlite3ResetInternalSchema(db, 0);
+  }
+  if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
+    /* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
+    ** the schema loaded, even if errors occured. In this situation the 
+    ** current sqlite3_prepare() operation will fail, but the following one
+    ** will attempt to compile the supplied statement against whatever subset
+    ** of the schema was loaded before the error occured. The primary
+    ** purpose of this is to allow access to the sqlite_master table
+    ** even when its contents have been corrupted.
+    */
+    DbSetProperty(db, iDb, DB_SchemaLoaded);
+    rc = SQLITE_OK;
+  }
+
+  /* Jump here for an error that occurs after successfully allocating
+  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
+  ** before that point, jump to error_out.
+  */
+leave_error_out:
+  sqlite3BtreeCloseCursor(curMain);
+  sqlite3_free(curMain);
+  sqlite3BtreeLeave(pDb->pBt);
+
+error_out:
+  if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+    db->mallocFailed = 1;
+  }
+  return rc;
+}
+
+/*
+** Initialize all database files - the main database file, the file
+** used to store temporary tables, and any additional database files
+** created using ATTACH statements.  Return a success code.  If an
+** error occurs, write an error message into *pzErrMsg.
+**
+** After a database is initialized, the DB_SchemaLoaded bit is set
+** bit is set in the flags field of the Db structure. If the database
+** file was of zero-length, then the DB_Empty flag is also set.
+*/
+SQLITE_PRIVATE int sqlite3Init(sqlite3 *db, char **pzErrMsg){
+  int i, rc;
+  int commit_internal = !(db->flags&SQLITE_InternChanges);
+  
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->init.busy ) return SQLITE_OK;
+  rc = SQLITE_OK;
+  db->init.busy = 1;
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
+    rc = sqlite3InitOne(db, i, pzErrMsg);
+    if( rc ){
+      sqlite3ResetInternalSchema(db, i);
+    }
+  }
+
+  /* Once all the other databases have been initialised, load the schema
+  ** for the TEMP database. This is loaded last, as the TEMP database
+  ** schema may contain references to objects in other databases.
+  */
+#ifndef SQLITE_OMIT_TEMPDB
+  if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
+    rc = sqlite3InitOne(db, 1, pzErrMsg);
+    if( rc ){
+      sqlite3ResetInternalSchema(db, 1);
+    }
+  }
+#endif
+
+  db->init.busy = 0;
+  if( rc==SQLITE_OK && commit_internal ){
+    sqlite3CommitInternalChanges(db);
+  }
+
+  return rc; 
+}
+
+/*
+** This routine is a no-op if the database schema is already initialised.
+** Otherwise, the schema is loaded. An error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse){
+  int rc = SQLITE_OK;
+  sqlite3 *db = pParse->db;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( !db->init.busy ){
+    rc = sqlite3Init(db, &pParse->zErrMsg);
+  }
+  if( rc!=SQLITE_OK ){
+    pParse->rc = rc;
+    pParse->nErr++;
+  }
+  return rc;
+}
+
+
+/*
+** Check schema cookies in all databases.  If any cookie is out
+** of date, return 0.  If all schema cookies are current, return 1.
+*/
+static int schemaIsValid(sqlite3 *db){
+  int iDb;
+  int rc;
+  BtCursor *curTemp;
+  int cookie;
+  int allOk = 1;
+
+  curTemp = (BtCursor *)sqlite3_malloc(sqlite3BtreeCursorSize());
+  if( curTemp ){
+    assert( sqlite3_mutex_held(db->mutex) );
+    for(iDb=0; allOk && iDb<db->nDb; iDb++){
+      Btree *pBt;
+      pBt = db->aDb[iDb].pBt;
+      if( pBt==0 ) continue;
+      memset(curTemp, 0, sqlite3BtreeCursorSize());
+      rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, curTemp);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
+        if( rc==SQLITE_OK && cookie!=db->aDb[iDb].pSchema->schema_cookie ){
+          allOk = 0;
+        }
+        sqlite3BtreeCloseCursor(curTemp);
+      }
+      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+        db->mallocFailed = 1;
+      }
+    }
+    sqlite3_free(curTemp);
+  }else{
+    allOk = 0;
+    db->mallocFailed = 1;
+  }
+
+  return allOk;
+}
+
+/*
+** Convert a schema pointer into the iDb index that indicates
+** which database file in db->aDb[] the schema refers to.
+**
+** If the same database is attached more than once, the first
+** attached database is returned.
+*/
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
+  int i = -1000000;
+
+  /* If pSchema is NULL, then return -1000000. This happens when code in 
+  ** expr.c is trying to resolve a reference to a transient table (i.e. one
+  ** created by a sub-select). In this case the return value of this 
+  ** function should never be used.
+  **
+  ** We return -1000000 instead of the more usual -1 simply because using
+  ** -1000000 as incorrectly using -1000000 index into db->aDb[] is much 
+  ** more likely to cause a segfault than -1 (of course there are assert()
+  ** statements too, but it never hurts to play the odds).
+  */
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( pSchema ){
+    for(i=0; i<db->nDb; i++){
+      if( db->aDb[i].pSchema==pSchema ){
+        break;
+      }
+    }
+    assert( i>=0 &&i>=0 &&  i<db->nDb );
+  }
+  return i;
+}
+
+/*
+** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  Parse sParse;
+  char *zErrMsg = 0;
+  int rc = SQLITE_OK;
+  int i;
+
+  assert( ppStmt );
+  *ppStmt = 0;
+  if( sqlite3SafetyOn(db) ){
+    return SQLITE_MISUSE;
+  }
+  assert( !db->mallocFailed );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* If any attached database schemas are locked, do not proceed with
+  ** compilation. Instead return SQLITE_LOCKED immediately.
+  */
+  for(i=0; i<db->nDb; i++) {
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      int rc;
+      rc = sqlite3BtreeSchemaLocked(pBt);
+      if( rc ){
+        const char *zDb = db->aDb[i].zName;
+        sqlite3Error(db, SQLITE_LOCKED, "database schema is locked: %s", zDb);
+        (void)sqlite3SafetyOff(db);
+        return SQLITE_LOCKED;
+      }
+    }
+  }
+  
+  memset(&sParse, 0, sizeof(sParse));
+  sParse.db = db;
+  if( nBytes>=0 && zSql[nBytes-1]!=0 ){
+    char *zSqlCopy;
+    int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+    if( nBytes>mxLen ){
+      sqlite3Error(db, SQLITE_TOOBIG, "statement too long");
+      (void)sqlite3SafetyOff(db);
+      return SQLITE_TOOBIG;
+    }
+    zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
+    if( zSqlCopy ){
+      sqlite3RunParser(&sParse, zSqlCopy, &zErrMsg);
+      sqlite3_free(zSqlCopy);
+      sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
+    }else{
+      sParse.zTail = &zSql[nBytes];
+    }
+  }else{
+    sqlite3RunParser(&sParse, zSql, &zErrMsg);
+  }
+
+  if( db->mallocFailed ){
+    sParse.rc = SQLITE_NOMEM;
+  }
+  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
+  if( sParse.checkSchema && !schemaIsValid(db) ){
+    sParse.rc = SQLITE_SCHEMA;
+  }
+  if( sParse.rc==SQLITE_SCHEMA ){
+    sqlite3ResetInternalSchema(db, 0);
+  }
+  if( db->mallocFailed ){
+    sParse.rc = SQLITE_NOMEM;
+  }
+  if( pzTail ){
+    *pzTail = sParse.zTail;
+  }
+  rc = sParse.rc;
+
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
+    if( sParse.explain==2 ){
+      sqlite3VdbeSetNumCols(sParse.pVdbe, 3);
+      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "order", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "from", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "detail", P4_STATIC);
+    }else{
+      sqlite3VdbeSetNumCols(sParse.pVdbe, 8);
+      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "addr", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "opcode", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "p1", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 3, COLNAME_NAME, "p2", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 4, COLNAME_NAME, "p3", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 5, COLNAME_NAME, "p4", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 6, COLNAME_NAME, "p5", P4_STATIC);
+      sqlite3VdbeSetColName(sParse.pVdbe, 7, COLNAME_NAME, "comment",P4_STATIC);
+    }
+  }
+#endif
+
+  if( sqlite3SafetyOff(db) ){
+    rc = SQLITE_MISUSE;
+  }
+
+  if( saveSqlFlag ){
+    sqlite3VdbeSetSql(sParse.pVdbe, zSql, sParse.zTail - zSql);
+  }
+  if( rc!=SQLITE_OK || db->mallocFailed ){
+    sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
+    assert(!(*ppStmt));
+  }else{
+    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
+  }
+
+  if( zErrMsg ){
+    sqlite3Error(db, rc, "%s", zErrMsg);
+    sqlite3_free(zErrMsg);
+  }else{
+    sqlite3Error(db, rc, 0);
+  }
+
+  rc = sqlite3ApiExit(db, rc);
+  assert( (rc&db->errMask)==rc );
+  return rc;
+}
+static int sqlite3LockAndPrepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, ppStmt, pzTail);
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Rerun the compilation of a statement after a schema change.
+** Return true if the statement was recompiled successfully.
+** Return false if there is an error of some kind.
+*/
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
+  int rc;
+  sqlite3_stmt *pNew;
+  const char *zSql;
+  sqlite3 *db;
+
+  assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
+  zSql = sqlite3_sql((sqlite3_stmt *)p);
+  assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
+  db = sqlite3VdbeDb(p);
+  assert( sqlite3_mutex_held(db->mutex) );
+  rc = sqlite3LockAndPrepare(db, zSql, -1, 0, &pNew, 0);
+  if( rc ){
+    if( rc==SQLITE_NOMEM ){
+      db->mallocFailed = 1;
+    }
+    assert( pNew==0 );
+    return 0;
+  }else{
+    assert( pNew!=0 );
+  }
+  sqlite3VdbeSwap((Vdbe*)pNew, p);
+  sqlite3_transfer_bindings(pNew, (sqlite3_stmt*)p);
+  sqlite3VdbeResetStepResult((Vdbe*)pNew);
+  sqlite3VdbeFinalize((Vdbe*)pNew);
+  return 1;
+}
+
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,1,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare16(
+  sqlite3 *db,              /* Database handle. */ 
+  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  int saveSqlFlag,          /* True to save SQL text into the sqlite3_stmt */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  /* This function currently works by first transforming the UTF-16
+  ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
+  ** tricky bit is figuring out the pointer to return in *pzTail.
+  */
+  char *zSql8;
+  const char *zTail8 = 0;
+  int rc = SQLITE_OK;
+
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  zSql8 = sqlite3Utf16to8(db, zSql, nBytes);
+  if( zSql8 ){
+    rc = sqlite3LockAndPrepare(db, zSql8, -1, saveSqlFlag, ppStmt, &zTail8);
+  }
+
+  if( zTail8 && pzTail ){
+    /* If sqlite3_prepare returns a tail pointer, we calculate the
+    ** equivalent pointer into the UTF-16 string by counting the unicode
+    ** characters between zSql8 and zTail8, and then returning a pointer
+    ** the same number of characters into the UTF-16 string.
+    */
+    int chars_parsed = sqlite3Utf8CharLen(zSql8, zTail8-zSql8);
+    *pzTail = (u8 *)zSql + sqlite3Utf16ByteLen(zSql, chars_parsed);
+  }
+  sqlite3_free(zSql8); 
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,              /* Database handle. */ 
+  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,              /* Database handle. */ 
+  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,1,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of prepare.c *********************************************/
+/************** Begin file select.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle SELECT statements in SQLite.
+**
+** $Id: select.c,v 1.429 2008/05/01 17:03:49 drh Exp $
+*/
+
+
+/*
+** Delete all the content of a Select structure but do not deallocate
+** the select structure itself.
+*/
+static void clearSelect(Select *p){
+  sqlite3ExprListDelete(p->pEList);
+  sqlite3SrcListDelete(p->pSrc);
+  sqlite3ExprDelete(p->pWhere);
+  sqlite3ExprListDelete(p->pGroupBy);
+  sqlite3ExprDelete(p->pHaving);
+  sqlite3ExprListDelete(p->pOrderBy);
+  sqlite3SelectDelete(p->pPrior);
+  sqlite3ExprDelete(p->pLimit);
+  sqlite3ExprDelete(p->pOffset);
+}
+
+/*
+** Initialize a SelectDest structure.
+*/
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
+  pDest->eDest = eDest;
+  pDest->iParm = iParm;
+  pDest->affinity = 0;
+  pDest->iMem = 0;
+  pDest->nMem = 0;
+}
+
+
+/*
+** Allocate a new Select structure and return a pointer to that
+** structure.
+*/
+SQLITE_PRIVATE Select *sqlite3SelectNew(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pEList,     /* which columns to include in the result */
+  SrcList *pSrc,        /* the FROM clause -- which tables to scan */
+  Expr *pWhere,         /* the WHERE clause */
+  ExprList *pGroupBy,   /* the GROUP BY clause */
+  Expr *pHaving,        /* the HAVING clause */
+  ExprList *pOrderBy,   /* the ORDER BY clause */
+  int isDistinct,       /* true if the DISTINCT keyword is present */
+  Expr *pLimit,         /* LIMIT value.  NULL means not used */
+  Expr *pOffset         /* OFFSET value.  NULL means no offset */
+){
+  Select *pNew;
+  Select standin;
+  sqlite3 *db = pParse->db;
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
+  assert( !pOffset || pLimit );   /* Can't have OFFSET without LIMIT. */
+  if( pNew==0 ){
+    pNew = &standin;
+    memset(pNew, 0, sizeof(*pNew));
+  }
+  if( pEList==0 ){
+    pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0,0,0), 0);
+  }
+  pNew->pEList = pEList;
+  pNew->pSrc = pSrc;
+  pNew->pWhere = pWhere;
+  pNew->pGroupBy = pGroupBy;
+  pNew->pHaving = pHaving;
+  pNew->pOrderBy = pOrderBy;
+  pNew->isDistinct = isDistinct;
+  pNew->op = TK_SELECT;
+  assert( pOffset==0 || pLimit!=0 );
+  pNew->pLimit = pLimit;
+  pNew->pOffset = pOffset;
+  pNew->iLimit = -1;
+  pNew->iOffset = -1;
+  pNew->addrOpenEphm[0] = -1;
+  pNew->addrOpenEphm[1] = -1;
+  pNew->addrOpenEphm[2] = -1;
+  if( pNew==&standin) {
+    clearSelect(pNew);
+    pNew = 0;
+  }
+  return pNew;
+}
+
+/*
+** Delete the given Select structure and all of its substructures.
+*/
+SQLITE_PRIVATE void sqlite3SelectDelete(Select *p){
+  if( p ){
+    clearSelect(p);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
+** type of join.  Return an integer constant that expresses that type
+** in terms of the following bit values:
+**
+**     JT_INNER
+**     JT_CROSS
+**     JT_OUTER
+**     JT_NATURAL
+**     JT_LEFT
+**     JT_RIGHT
+**
+** A full outer join is the combination of JT_LEFT and JT_RIGHT.
+**
+** If an illegal or unsupported join type is seen, then still return
+** a join type, but put an error in the pParse structure.
+*/
+SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
+  int jointype = 0;
+  Token *apAll[3];
+  Token *p;
+  static const struct {
+    const char zKeyword[8];
+    u8 nChar;
+    u8 code;
+  } keywords[] = {
+    { "natural", 7, JT_NATURAL },
+    { "left",    4, JT_LEFT|JT_OUTER },
+    { "right",   5, JT_RIGHT|JT_OUTER },
+    { "full",    4, JT_LEFT|JT_RIGHT|JT_OUTER },
+    { "outer",   5, JT_OUTER },
+    { "inner",   5, JT_INNER },
+    { "cross",   5, JT_INNER|JT_CROSS },
+  };
+  int i, j;
+  apAll[0] = pA;
+  apAll[1] = pB;
+  apAll[2] = pC;
+  for(i=0; i<3 && apAll[i]; i++){
+    p = apAll[i];
+    for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
+      if( p->n==keywords[j].nChar 
+          && sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
+        jointype |= keywords[j].code;
+        break;
+      }
+    }
+    if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
+      jointype |= JT_ERROR;
+      break;
+    }
+  }
+  if(
+     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
+     (jointype & JT_ERROR)!=0
+  ){
+    const char *zSp1 = " ";
+    const char *zSp2 = " ";
+    if( pB==0 ){ zSp1++; }
+    if( pC==0 ){ zSp2++; }
+    sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
+       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
+    jointype = JT_INNER;
+  }else if( jointype & JT_RIGHT ){
+    sqlite3ErrorMsg(pParse, 
+      "RIGHT and FULL OUTER JOINs are not currently supported");
+    jointype = JT_INNER;
+  }
+  return jointype;
+}
+
+/*
+** Return the index of a column in a table.  Return -1 if the column
+** is not contained in the table.
+*/
+static int columnIndex(Table *pTab, const char *zCol){
+  int i;
+  for(i=0; i<pTab->nCol; i++){
+    if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Set the value of a token to a '\000'-terminated string.
+*/
+static void setToken(Token *p, const char *z){
+  p->z = (u8*)z;
+  p->n = z ? strlen(z) : 0;
+  p->dyn = 0;
+}
+
+/*
+** Set the token to the double-quoted and escaped version of the string pointed
+** to by z. For example;
+**
+**    {a"bc}  ->  {"a""bc"}
+*/
+static void setQuotedToken(Parse *pParse, Token *p, const char *z){
+
+  /* Check if the string contains any " characters. If it does, then
+  ** this function will malloc space to create a quoted version of
+  ** the string in. Otherwise, save a call to sqlite3MPrintf() by
+  ** just copying the pointer to the string.
+  */
+  const char *z2 = z;
+  while( *z2 ){
+    if( *z2=='"' ) break;
+    z2++;
+  }
+
+  if( *z2 ){
+    /* String contains " characters - copy and quote the string. */
+    p->z = (u8 *)sqlite3MPrintf(pParse->db, "\"%w\"", z);
+    if( p->z ){
+      p->n = strlen((char *)p->z);
+      p->dyn = 1;
+    }
+  }else{
+    /* String contains no " characters - copy the pointer. */
+    p->z = (u8*)z;
+    p->n = (z2 - z);
+    p->dyn = 0;
+  }
+}
+
+/*
+** Create an expression node for an identifier with the name of zName
+*/
+SQLITE_PRIVATE Expr *sqlite3CreateIdExpr(Parse *pParse, const char *zName){
+  Token dummy;
+  setToken(&dummy, zName);
+  return sqlite3PExpr(pParse, TK_ID, 0, 0, &dummy);
+}
+
+/*
+** Add a term to the WHERE expression in *ppExpr that requires the
+** zCol column to be equal in the two tables pTab1 and pTab2.
+*/
+static void addWhereTerm(
+  Parse *pParse,           /* Parsing context */
+  const char *zCol,        /* Name of the column */
+  const Table *pTab1,      /* First table */
+  const char *zAlias1,     /* Alias for first table.  May be NULL */
+  const Table *pTab2,      /* Second table */
+  const char *zAlias2,     /* Alias for second table.  May be NULL */
+  int iRightJoinTable,     /* VDBE cursor for the right table */
+  Expr **ppExpr,           /* Add the equality term to this expression */
+  int isOuterJoin          /* True if dealing with an OUTER join */
+){
+  Expr *pE1a, *pE1b, *pE1c;
+  Expr *pE2a, *pE2b, *pE2c;
+  Expr *pE;
+
+  pE1a = sqlite3CreateIdExpr(pParse, zCol);
+  pE2a = sqlite3CreateIdExpr(pParse, zCol);
+  if( zAlias1==0 ){
+    zAlias1 = pTab1->zName;
+  }
+  pE1b = sqlite3CreateIdExpr(pParse, zAlias1);
+  if( zAlias2==0 ){
+    zAlias2 = pTab2->zName;
+  }
+  pE2b = sqlite3CreateIdExpr(pParse, zAlias2);
+  pE1c = sqlite3PExpr(pParse, TK_DOT, pE1b, pE1a, 0);
+  pE2c = sqlite3PExpr(pParse, TK_DOT, pE2b, pE2a, 0);
+  pE = sqlite3PExpr(pParse, TK_EQ, pE1c, pE2c, 0);
+  if( pE && isOuterJoin ){
+    ExprSetProperty(pE, EP_FromJoin);
+    pE->iRightJoinTable = iRightJoinTable;
+  }
+  *ppExpr = sqlite3ExprAnd(pParse->db,*ppExpr, pE);
+}
+
+/*
+** Set the EP_FromJoin property on all terms of the given expression.
+** And set the Expr.iRightJoinTable to iTable for every term in the
+** expression.
+**
+** The EP_FromJoin property is used on terms of an expression to tell
+** the LEFT OUTER JOIN processing logic that this term is part of the
+** join restriction specified in the ON or USING clause and not a part
+** of the more general WHERE clause.  These terms are moved over to the
+** WHERE clause during join processing but we need to remember that they
+** originated in the ON or USING clause.
+**
+** The Expr.iRightJoinTable tells the WHERE clause processing that the
+** expression depends on table iRightJoinTable even if that table is not
+** explicitly mentioned in the expression.  That information is needed
+** for cases like this:
+**
+**    SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
+**
+** The where clause needs to defer the handling of the t1.x=5
+** term until after the t2 loop of the join.  In that way, a
+** NULL t2 row will be inserted whenever t1.x!=5.  If we do not
+** defer the handling of t1.x=5, it will be processed immediately
+** after the t1 loop and rows with t1.x!=5 will never appear in
+** the output, which is incorrect.
+*/
+static void setJoinExpr(Expr *p, int iTable){
+  while( p ){
+    ExprSetProperty(p, EP_FromJoin);
+    p->iRightJoinTable = iTable;
+    setJoinExpr(p->pLeft, iTable);
+    p = p->pRight;
+  } 
+}
+
+/*
+** This routine processes the join information for a SELECT statement.
+** ON and USING clauses are converted into extra terms of the WHERE clause.
+** NATURAL joins also create extra WHERE clause terms.
+**
+** The terms of a FROM clause are contained in the Select.pSrc structure.
+** The left most table is the first entry in Select.pSrc.  The right-most
+** table is the last entry.  The join operator is held in the entry to
+** the left.  Thus entry 0 contains the join operator for the join between
+** entries 0 and 1.  Any ON or USING clauses associated with the join are
+** also attached to the left entry.
+**
+** This routine returns the number of errors encountered.
+*/
+static int sqliteProcessJoin(Parse *pParse, Select *p){
+  SrcList *pSrc;                  /* All tables in the FROM clause */
+  int i, j;                       /* Loop counters */
+  struct SrcList_item *pLeft;     /* Left table being joined */
+  struct SrcList_item *pRight;    /* Right table being joined */
+
+  pSrc = p->pSrc;
+  pLeft = &pSrc->a[0];
+  pRight = &pLeft[1];
+  for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
+    Table *pLeftTab = pLeft->pTab;
+    Table *pRightTab = pRight->pTab;
+    int isOuter;
+
+    if( pLeftTab==0 || pRightTab==0 ) continue;
+    isOuter = (pRight->jointype & JT_OUTER)!=0;
+
+    /* When the NATURAL keyword is present, add WHERE clause terms for
+    ** every column that the two tables have in common.
+    */
+    if( pRight->jointype & JT_NATURAL ){
+      if( pRight->pOn || pRight->pUsing ){
+        sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
+           "an ON or USING clause", 0);
+        return 1;
+      }
+      for(j=0; j<pLeftTab->nCol; j++){
+        char *zName = pLeftTab->aCol[j].zName;
+        if( columnIndex(pRightTab, zName)>=0 ){
+          addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias, 
+                              pRightTab, pRight->zAlias,
+                              pRight->iCursor, &p->pWhere, isOuter);
+          
+        }
+      }
+    }
+
+    /* Disallow both ON and USING clauses in the same join
+    */
+    if( pRight->pOn && pRight->pUsing ){
+      sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
+        "clauses in the same join");
+      return 1;
+    }
+
+    /* Add the ON clause to the end of the WHERE clause, connected by
+    ** an AND operator.
+    */
+    if( pRight->pOn ){
+      if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
+      p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
+      pRight->pOn = 0;
+    }
+
+    /* Create extra terms on the WHERE clause for each column named
+    ** in the USING clause.  Example: If the two tables to be joined are 
+    ** A and B and the USING clause names X, Y, and Z, then add this
+    ** to the WHERE clause:    A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
+    ** Report an error if any column mentioned in the USING clause is
+    ** not contained in both tables to be joined.
+    */
+    if( pRight->pUsing ){
+      IdList *pList = pRight->pUsing;
+      for(j=0; j<pList->nId; j++){
+        char *zName = pList->a[j].zName;
+        if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
+          sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
+            "not present in both tables", zName);
+          return 1;
+        }
+        addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias, 
+                            pRightTab, pRight->zAlias,
+                            pRight->iCursor, &p->pWhere, isOuter);
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Insert code into "v" that will push the record on the top of the
+** stack into the sorter.
+*/
+static void pushOntoSorter(
+  Parse *pParse,         /* Parser context */
+  ExprList *pOrderBy,    /* The ORDER BY clause */
+  Select *pSelect,       /* The whole SELECT statement */
+  int regData            /* Register holding data to be sorted */
+){
+  Vdbe *v = pParse->pVdbe;
+  int nExpr = pOrderBy->nExpr;
+  int regBase = sqlite3GetTempRange(pParse, nExpr+2);
+  int regRecord = sqlite3GetTempReg(pParse);
+  sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
+  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
+  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1);
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
+  if( pSelect->iLimit>=0 ){
+    int addr1, addr2;
+    int iLimit;
+    if( pSelect->pOffset ){
+      iLimit = pSelect->iOffset+1;
+    }else{
+      iLimit = pSelect->iLimit;
+    }
+    addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
+    sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
+    addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
+    sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
+    sqlite3VdbeJumpHere(v, addr2);
+    pSelect->iLimit = -1;
+  }
+}
+
+/*
+** Add code to implement the OFFSET
+*/
+static void codeOffset(
+  Vdbe *v,          /* Generate code into this VM */
+  Select *p,        /* The SELECT statement being coded */
+  int iContinue     /* Jump here to skip the current record */
+){
+  if( p->iOffset>=0 && iContinue!=0 ){
+    int addr;
+    sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
+    addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
+    VdbeComment((v, "skip OFFSET records"));
+    sqlite3VdbeJumpHere(v, addr);
+  }
+}
+
+/*
+** Add code that will check to make sure the N registers starting at iMem
+** form a distinct entry.  iTab is a sorting index that holds previously
+** seen combinations of the N values.  A new entry is made in iTab
+** if the current N values are new.
+**
+** A jump to addrRepeat is made and the N+1 values are popped from the
+** stack if the top N elements are not distinct.
+*/
+static void codeDistinct(
+  Parse *pParse,     /* Parsing and code generating context */
+  int iTab,          /* A sorting index used to test for distinctness */
+  int addrRepeat,    /* Jump to here if not distinct */
+  int N,             /* Number of elements */
+  int iMem           /* First element */
+){
+  Vdbe *v;
+  int r1;
+
+  v = pParse->pVdbe;
+  r1 = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
+  sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
+  sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Generate an error message when a SELECT is used within a subexpression
+** (example:  "a IN (SELECT * FROM table)") but it has more than 1 result
+** column.  We do this in a subroutine because the error occurs in multiple
+** places.
+*/
+static int checkForMultiColumnSelectError(
+  Parse *pParse,       /* Parse context. */
+  SelectDest *pDest,   /* Destination of SELECT results */
+  int nExpr            /* Number of result columns returned by SELECT */
+){
+  int eDest = pDest->eDest;
+  if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
+    sqlite3ErrorMsg(pParse, "only a single result allowed for "
+       "a SELECT that is part of an expression");
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** This routine generates the code for the inside of the inner loop
+** of a SELECT.
+**
+** If srcTab and nColumn are both zero, then the pEList expressions
+** are evaluated in order to get the data for this row.  If nColumn>0
+** then data is pulled from srcTab and pEList is used only to get the
+** datatypes for each column.
+*/
+static void selectInnerLoop(
+  Parse *pParse,          /* The parser context */
+  Select *p,              /* The complete select statement being coded */
+  ExprList *pEList,       /* List of values being extracted */
+  int srcTab,             /* Pull data from this table */
+  int nColumn,            /* Number of columns in the source table */
+  ExprList *pOrderBy,     /* If not NULL, sort results using this key */
+  int distinct,           /* If >=0, make sure results are distinct */
+  SelectDest *pDest,      /* How to dispose of the results */
+  int iContinue,          /* Jump here to continue with next row */
+  int iBreak,             /* Jump here to break out of the inner loop */
+  char *aff               /* affinity string if eDest is SRT_Union */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int hasDistinct;        /* True if the DISTINCT keyword is present */
+  int regResult;              /* Start of memory holding result set */
+  int eDest = pDest->eDest;   /* How to dispose of results */
+  int iParm = pDest->iParm;   /* First argument to disposal method */
+  int nResultCol;             /* Number of result columns */
+
+  if( v==0 ) return;
+  assert( pEList!=0 );
+
+  /* If there was a LIMIT clause on the SELECT statement, then do the check
+  ** to see if this row should be output.
+  */
+  hasDistinct = distinct>=0 && pEList->nExpr>0;
+  if( pOrderBy==0 && !hasDistinct ){
+    codeOffset(v, p, iContinue);
+  }
+
+  /* Pull the requested columns.
+  */
+  if( nColumn>0 ){
+    nResultCol = nColumn;
+  }else{
+    nResultCol = pEList->nExpr;
+  }
+  if( pDest->iMem==0 ){
+    pDest->iMem = sqlite3GetTempRange(pParse, nResultCol);
+    pDest->nMem = nResultCol;
+  }else if( pDest->nMem!=nResultCol ){
+    /* This happens when two SELECTs of a compound SELECT have differing
+    ** numbers of result columns.  The error message will be generated by
+    ** a higher-level routine. */
+    return;
+  }
+  regResult = pDest->iMem;
+  if( nColumn>0 ){
+    for(i=0; i<nColumn; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
+    }
+  }else if( eDest!=SRT_Exists ){
+    /* If the destination is an EXISTS(...) expression, the actual
+    ** values returned by the SELECT are not required.
+    */
+    sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Callback);
+  }
+  nColumn = nResultCol;
+
+  /* If the DISTINCT keyword was present on the SELECT statement
+  ** and this row has been seen before, then do not make this row
+  ** part of the result.
+  */
+  if( hasDistinct ){
+    assert( pEList!=0 );
+    assert( pEList->nExpr==nColumn );
+    codeDistinct(pParse, distinct, iContinue, nColumn, regResult);
+    if( pOrderBy==0 ){
+      codeOffset(v, p, iContinue);
+    }
+  }
+
+  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
+    return;
+  }
+
+  switch( eDest ){
+    /* In this mode, write each query result to the key of the temporary
+    ** table iParm.
+    */
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+    case SRT_Union: {
+      int r1;
+      r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+      if( aff ){
+        sqlite3VdbeChangeP4(v, -1, aff, P4_STATIC);
+      }
+      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+    /* Construct a record from the query result, but instead of
+    ** saving that record, use it as a key to delete elements from
+    ** the temporary table iParm.
+    */
+    case SRT_Except: {
+      sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
+      break;
+    }
+#endif
+
+    /* Store the result as data using a unique key.
+    */
+    case SRT_Table:
+    case SRT_EphemTab: {
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+      if( pOrderBy ){
+        pushOntoSorter(pParse, pOrderBy, p, r1);
+      }else{
+        int r2 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
+        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
+        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+        sqlite3ReleaseTempReg(pParse, r2);
+      }
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+    ** then there should be a single item on the stack.  Write this
+    ** item into the set table with bogus data.
+    */
+    case SRT_Set: {
+      int addr2;
+
+      assert( nColumn==1 );
+      addr2 = sqlite3VdbeAddOp1(v, OP_IsNull, regResult);
+      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
+      if( pOrderBy ){
+        /* At first glance you would think we could optimize out the
+        ** ORDER BY in this case since the order of entries in the set
+        ** does not matter.  But there might be a LIMIT clause, in which
+        ** case the order does matter */
+        pushOntoSorter(pParse, pOrderBy, p, regResult);
+      }else{
+        int r1 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1);
+        sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
+        sqlite3ReleaseTempReg(pParse, r1);
+      }
+      sqlite3VdbeJumpHere(v, addr2);
+      break;
+    }
+
+    /* If any row exist in the result set, record that fact and abort.
+    */
+    case SRT_Exists: {
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+
+    /* If this is a scalar select that is part of an expression, then
+    ** store the results in the appropriate memory cell and break out
+    ** of the scan loop.
+    */
+    case SRT_Mem: {
+      assert( nColumn==1 );
+      if( pOrderBy ){
+        pushOntoSorter(pParse, pOrderBy, p, regResult);
+      }else{
+        sqlite3ExprCodeMove(pParse, regResult, iParm);
+        /* The LIMIT clause will jump out of the loop for us */
+      }
+      break;
+    }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+    /* Send the data to the callback function or to a subroutine.  In the
+    ** case of a subroutine, the subroutine itself is responsible for
+    ** popping the data from the stack.
+    */
+    case SRT_Subroutine:
+    case SRT_Callback: {
+      if( pOrderBy ){
+        int r1 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+        pushOntoSorter(pParse, pOrderBy, p, r1);
+        sqlite3ReleaseTempReg(pParse, r1);
+      }else if( eDest==SRT_Subroutine ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, 0, iParm);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
+        sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
+      }
+      break;
+    }
+
+#if !defined(SQLITE_OMIT_TRIGGER)
+    /* Discard the results.  This is used for SELECT statements inside
+    ** the body of a TRIGGER.  The purpose of such selects is to call
+    ** user-defined functions that have side effects.  We do not care
+    ** about the actual results of the select.
+    */
+    default: {
+      assert( eDest==SRT_Discard );
+      break;
+    }
+#endif
+  }
+
+  /* Jump to the end of the loop if the LIMIT is reached.
+  */
+  if( p->iLimit>=0 && pOrderBy==0 ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+  }
+}
+
+/*
+** Given an expression list, generate a KeyInfo structure that records
+** the collating sequence for each expression in that expression list.
+**
+** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
+** KeyInfo structure is appropriate for initializing a virtual index to
+** implement that clause.  If the ExprList is the result set of a SELECT
+** then the KeyInfo structure is appropriate for initializing a virtual
+** index to implement a DISTINCT test.
+**
+** Space to hold the KeyInfo structure is obtain from malloc.  The calling
+** function is responsible for seeing that this structure is eventually
+** freed.  Add the KeyInfo structure to the P4 field of an opcode using
+** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
+*/
+static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
+  sqlite3 *db = pParse->db;
+  int nExpr;
+  KeyInfo *pInfo;
+  struct ExprList_item *pItem;
+  int i;
+
+  nExpr = pList->nExpr;
+  pInfo = sqlite3DbMallocZero(db, sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
+  if( pInfo ){
+    pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
+    pInfo->nField = nExpr;
+    pInfo->enc = ENC(db);
+    for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
+      CollSeq *pColl;
+      pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+      if( !pColl ){
+        pColl = db->pDfltColl;
+      }
+      pInfo->aColl[i] = pColl;
+      pInfo->aSortOrder[i] = pItem->sortOrder;
+    }
+  }
+  return pInfo;
+}
+
+
+/*
+** If the inner loop was generated using a non-null pOrderBy argument,
+** then the results were placed in a sorter.  After the loop is terminated
+** we need to run the sorter and output the results.  The following
+** routine generates the code needed to do that.
+*/
+static void generateSortTail(
+  Parse *pParse,    /* Parsing context */
+  Select *p,        /* The SELECT statement */
+  Vdbe *v,          /* Generate code into this VDBE */
+  int nColumn,      /* Number of columns of data */
+  SelectDest *pDest /* Write the sorted results here */
+){
+  int brk = sqlite3VdbeMakeLabel(v);
+  int cont = sqlite3VdbeMakeLabel(v);
+  int addr;
+  int iTab;
+  int pseudoTab = 0;
+  ExprList *pOrderBy = p->pOrderBy;
+
+  int eDest = pDest->eDest;
+  int iParm = pDest->iParm;
+
+  int regRow;
+  int regRowid;
+
+  iTab = pOrderBy->iECursor;
+  if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
+    pseudoTab = pParse->nTab++;
+    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nColumn);
+    sqlite3VdbeAddOp2(v, OP_OpenPseudo, pseudoTab, eDest==SRT_Callback);
+  }
+  addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, brk);
+  codeOffset(v, p, cont);
+  regRow = sqlite3GetTempReg(pParse);
+  regRowid = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr + 1, regRow);
+  switch( eDest ){
+    case SRT_Table:
+    case SRT_EphemTab: {
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
+      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case SRT_Set: {
+      int j1;
+      assert( nColumn==1 );
+      j1 = sqlite3VdbeAddOp1(v, OP_IsNull, regRow);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, &p->affinity, 1);
+      sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
+      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
+      sqlite3VdbeJumpHere(v, j1);
+      break;
+    }
+    case SRT_Mem: {
+      assert( nColumn==1 );
+      sqlite3ExprCodeMove(pParse, regRow, iParm);
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+#endif
+    case SRT_Callback:
+    case SRT_Subroutine: {
+      int i;
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, pseudoTab, regRow, regRowid);
+      for(i=0; i<nColumn; i++){
+        assert( regRow!=pDest->iMem+i );
+        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
+      }
+      if( eDest==SRT_Callback ){
+        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
+        sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Gosub, 0, iParm);
+      }
+      break;
+    }
+    default: {
+      /* Do nothing */
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regRow);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+
+  /* Jump to the end of the loop when the LIMIT is reached
+  */
+  if( p->iLimit>=0 ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, brk);
+  }
+
+  /* The bottom of the loop
+  */
+  sqlite3VdbeResolveLabel(v, cont);
+  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
+  sqlite3VdbeResolveLabel(v, brk);
+  if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
+    sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
+  }
+
+}
+
+/*
+** Return a pointer to a string containing the 'declaration type' of the
+** expression pExpr. The string may be treated as static by the caller.
+**
+** The declaration type is the exact datatype definition extracted from the
+** original CREATE TABLE statement if the expression is a column. The
+** declaration type for a ROWID field is INTEGER. Exactly when an expression
+** is considered a column can be complex in the presence of subqueries. The
+** result-set expression in all of the following SELECT statements is 
+** considered a column by this function.
+**
+**   SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl);
+**   SELECT abc FROM (SELECT col AS abc FROM tbl);
+** 
+** The declaration type for any expression other than a column is NULL.
+*/
+static const char *columnType(
+  NameContext *pNC, 
+  Expr *pExpr,
+  const char **pzOriginDb,
+  const char **pzOriginTab,
+  const char **pzOriginCol
+){
+  char const *zType = 0;
+  char const *zOriginDb = 0;
+  char const *zOriginTab = 0;
+  char const *zOriginCol = 0;
+  int j;
+  if( pExpr==0 || pNC->pSrcList==0 ) return 0;
+
+  switch( pExpr->op ){
+    case TK_AGG_COLUMN:
+    case TK_COLUMN: {
+      /* The expression is a column. Locate the table the column is being
+      ** extracted from in NameContext.pSrcList. This table may be real
+      ** database table or a subquery.
+      */
+      Table *pTab = 0;            /* Table structure column is extracted from */
+      Select *pS = 0;             /* Select the column is extracted from */
+      int iCol = pExpr->iColumn;  /* Index of column in pTab */
+      while( pNC && !pTab ){
+        SrcList *pTabList = pNC->pSrcList;
+        for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
+        if( j<pTabList->nSrc ){
+          pTab = pTabList->a[j].pTab;
+          pS = pTabList->a[j].pSelect;
+        }else{
+          pNC = pNC->pNext;
+        }
+      }
+
+      if( pTab==0 ){
+        /* FIX ME:
+        ** This can occurs if you have something like "SELECT new.x;" inside
+        ** a trigger.  In other words, if you reference the special "new"
+        ** table in the result set of a select.  We do not have a good way
+        ** to find the actual table type, so call it "TEXT".  This is really
+        ** something of a bug, but I do not know how to fix it.
+        **
+        ** This code does not produce the correct answer - it just prevents
+        ** a segfault.  See ticket #1229.
+        */
+        zType = "TEXT";
+        break;
+      }
+
+      assert( pTab );
+      if( pS ){
+        /* The "table" is actually a sub-select or a view in the FROM clause
+        ** of the SELECT statement. Return the declaration type and origin
+        ** data for the result-set column of the sub-select.
+        */
+        if( iCol>=0 && iCol<pS->pEList->nExpr ){
+          /* If iCol is less than zero, then the expression requests the
+          ** rowid of the sub-select or view. This expression is legal (see 
+          ** test case misc2.2.2) - it always evaluates to NULL.
+          */
+          NameContext sNC;
+          Expr *p = pS->pEList->a[iCol].pExpr;
+          sNC.pSrcList = pS->pSrc;
+          sNC.pNext = 0;
+          sNC.pParse = pNC->pParse;
+          zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
+        }
+      }else if( pTab->pSchema ){
+        /* A real table */
+        assert( !pS );
+        if( iCol<0 ) iCol = pTab->iPKey;
+        assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+        if( iCol<0 ){
+          zType = "INTEGER";
+          zOriginCol = "rowid";
+        }else{
+          zType = pTab->aCol[iCol].zType;
+          zOriginCol = pTab->aCol[iCol].zName;
+        }
+        zOriginTab = pTab->zName;
+        if( pNC->pParse ){
+          int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
+          zOriginDb = pNC->pParse->db->aDb[iDb].zName;
+        }
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT: {
+      /* The expression is a sub-select. Return the declaration type and
+      ** origin info for the single column in the result set of the SELECT
+      ** statement.
+      */
+      NameContext sNC;
+      Select *pS = pExpr->pSelect;
+      Expr *p = pS->pEList->a[0].pExpr;
+      sNC.pSrcList = pS->pSrc;
+      sNC.pNext = pNC;
+      sNC.pParse = pNC->pParse;
+      zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
+      break;
+    }
+#endif
+  }
+  
+  if( pzOriginDb ){
+    assert( pzOriginTab && pzOriginCol );
+    *pzOriginDb = zOriginDb;
+    *pzOriginTab = zOriginTab;
+    *pzOriginCol = zOriginCol;
+  }
+  return zType;
+}
+
+/*
+** Generate code that will tell the VDBE the declaration types of columns
+** in the result set.
+*/
+static void generateColumnTypes(
+  Parse *pParse,      /* Parser context */
+  SrcList *pTabList,  /* List of tables */
+  ExprList *pEList    /* Expressions defining the result set */
+){
+#ifndef SQLITE_OMIT_DECLTYPE
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  NameContext sNC;
+  sNC.pSrcList = pTabList;
+  sNC.pParse = pParse;
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p = pEList->a[i].pExpr;
+    const char *zType;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+    const char *zOrigDb = 0;
+    const char *zOrigTab = 0;
+    const char *zOrigCol = 0;
+    zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+
+    /* The vdbe must make its own copy of the column-type and other 
+    ** column specific strings, in case the schema is reset before this
+    ** virtual machine is deleted.
+    */
+    sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P4_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P4_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P4_TRANSIENT);
+#else
+    zType = columnType(&sNC, p, 0, 0, 0);
+#endif
+    sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P4_TRANSIENT);
+  }
+#endif /* SQLITE_OMIT_DECLTYPE */
+}
+
+/*
+** Generate code that will tell the VDBE the names of columns
+** in the result set.  This information is used to provide the
+** azCol[] values in the callback.
+*/
+static void generateColumnNames(
+  Parse *pParse,      /* Parser context */
+  SrcList *pTabList,  /* List of tables */
+  ExprList *pEList    /* Expressions defining the result set */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i, j;
+  sqlite3 *db = pParse->db;
+  int fullNames, shortNames;
+
+#ifndef SQLITE_OMIT_EXPLAIN
+  /* If this is an EXPLAIN, skip this step */
+  if( pParse->explain ){
+    return;
+  }
+#endif
+
+  assert( v!=0 );
+  if( pParse->colNamesSet || v==0 || db->mallocFailed ) return;
+  pParse->colNamesSet = 1;
+  fullNames = (db->flags & SQLITE_FullColNames)!=0;
+  shortNames = (db->flags & SQLITE_ShortColNames)!=0;
+  sqlite3VdbeSetNumCols(v, pEList->nExpr);
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p;
+    p = pEList->a[i].pExpr;
+    if( p==0 ) continue;
+    if( pEList->a[i].zName ){
+      char *zName = pEList->a[i].zName;
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
+      continue;
+    }
+    if( p->op==TK_COLUMN && pTabList ){
+      Table *pTab;
+      char *zCol;
+      int iCol = p->iColumn;
+      for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
+      assert( j<pTabList->nSrc );
+      pTab = pTabList->a[j].pTab;
+      if( iCol<0 ) iCol = pTab->iPKey;
+      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+      if( iCol<0 ){
+        zCol = "rowid";
+      }else{
+        zCol = pTab->aCol[iCol].zName;
+      }
+      if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
+      }else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
+        char *zName = 0;
+        char *zTab;
+ 
+        zTab = pTabList->a[j].zAlias;
+        if( fullNames || zTab==0 ) zTab = pTab->zName;
+        sqlite3SetString(&zName, zTab, ".", zCol, (char*)0);
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P4_DYNAMIC);
+      }else{
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
+      }
+    }else if( p->span.z && p->span.z[0] ){
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
+      /* sqlite3VdbeCompressSpace(v, addr); */
+    }else{
+      char zName[30];
+      assert( p->op!=TK_COLUMN || pTabList==0 );
+      sqlite3_snprintf(sizeof(zName), zName, "column%d", i+1);
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, 0);
+    }
+  }
+  generateColumnTypes(pParse, pTabList, pEList);
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Name of the connection operator, used for error messages.
+*/
+static const char *selectOpName(int id){
+  char *z;
+  switch( id ){
+    case TK_ALL:       z = "UNION ALL";   break;
+    case TK_INTERSECT: z = "INTERSECT";   break;
+    case TK_EXCEPT:    z = "EXCEPT";      break;
+    default:           z = "UNION";       break;
+  }
+  return z;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/*
+** Forward declaration
+*/
+static int prepSelectStmt(Parse*, Select*);
+
+/*
+** Given a SELECT statement, generate a Table structure that describes
+** the result set of that SELECT.
+*/
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
+  Table *pTab;
+  int i, j;
+  ExprList *pEList;
+  Column *aCol, *pCol;
+  sqlite3 *db = pParse->db;
+
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  if( prepSelectStmt(pParse, pSelect) ){
+    return 0;
+  }
+  if( sqlite3SelectResolve(pParse, pSelect, 0) ){
+    return 0;
+  }
+  pTab = sqlite3DbMallocZero(db, sizeof(Table) );
+  if( pTab==0 ){
+    return 0;
+  }
+  pTab->nRef = 1;
+  pTab->zName = zTabName ? sqlite3DbStrDup(db, zTabName) : 0;
+  pEList = pSelect->pEList;
+  pTab->nCol = pEList->nExpr;
+  assert( pTab->nCol>0 );
+  pTab->aCol = aCol = sqlite3DbMallocZero(db, sizeof(pTab->aCol[0])*pTab->nCol);
+  for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
+    Expr *p, *pR;
+    char *zType;
+    char *zName;
+    int nName;
+    CollSeq *pColl;
+    int cnt;
+    NameContext sNC;
+    
+    /* Get an appropriate name for the column
+    */
+    p = pEList->a[i].pExpr;
+    assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
+    if( (zName = pEList->a[i].zName)!=0 ){
+      /* If the column contains an "AS <name>" phrase, use <name> as the name */
+      zName = sqlite3DbStrDup(db, zName);
+    }else if( p->op==TK_DOT 
+              && (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
+      /* For columns of the from A.B use B as the name */
+      zName = sqlite3MPrintf(db, "%T", &pR->token);
+    }else if( p->span.z && p->span.z[0] ){
+      /* Use the original text of the column expression as its name */
+      zName = sqlite3MPrintf(db, "%T", &p->span);
+    }else{
+      /* If all else fails, make up a name */
+      zName = sqlite3MPrintf(db, "column%d", i+1);
+    }
+    if( !zName || db->mallocFailed ){
+      db->mallocFailed = 1;
+      sqlite3_free(zName);
+      sqlite3DeleteTable(pTab);
+      return 0;
+    }
+    sqlite3Dequote(zName);
+
+    /* Make sure the column name is unique.  If the name is not unique,
+    ** append a integer to the name so that it becomes unique.
+    */
+    nName = strlen(zName);
+    for(j=cnt=0; j<i; j++){
+      if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
+        zName[nName] = 0;
+        zName = sqlite3MPrintf(db, "%z:%d", zName, ++cnt);
+        j = -1;
+        if( zName==0 ) break;
+      }
+    }
+    pCol->zName = zName;
+
+    /* Get the typename, type affinity, and collating sequence for the
+    ** column.
+    */
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pSrcList = pSelect->pSrc;
+    zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
+    pCol->zType = zType;
+    pCol->affinity = sqlite3ExprAffinity(p);
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    if( pColl ){
+      pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
+    }
+  }
+  pTab->iPKey = -1;
+  return pTab;
+}
+
+/*
+** Prepare a SELECT statement for processing by doing the following
+** things:
+**
+**    (1)  Make sure VDBE cursor numbers have been assigned to every
+**         element of the FROM clause.
+**
+**    (2)  Fill in the pTabList->a[].pTab fields in the SrcList that 
+**         defines FROM clause.  When views appear in the FROM clause,
+**         fill pTabList->a[].pSelect with a copy of the SELECT statement
+**         that implements the view.  A copy is made of the view's SELECT
+**         statement so that we can freely modify or delete that statement
+**         without worrying about messing up the presistent representation
+**         of the view.
+**
+**    (3)  Add terms to the WHERE clause to accomodate the NATURAL keyword
+**         on joins and the ON and USING clause of joins.
+**
+**    (4)  Scan the list of columns in the result set (pEList) looking
+**         for instances of the "*" operator or the TABLE.* operator.
+**         If found, expand each "*" to be every column in every table
+**         and TABLE.* to be every column in TABLE.
+**
+** Return 0 on success.  If there are problems, leave an error message
+** in pParse and return non-zero.
+*/
+static int prepSelectStmt(Parse *pParse, Select *p){
+  int i, j, k, rc;
+  SrcList *pTabList;
+  ExprList *pEList;
+  struct SrcList_item *pFrom;
+  sqlite3 *db = pParse->db;
+
+  if( p==0 || p->pSrc==0 || db->mallocFailed ){
+    return 1;
+  }
+  pTabList = p->pSrc;
+  pEList = p->pEList;
+
+  /* Make sure cursor numbers have been assigned to all entries in
+  ** the FROM clause of the SELECT statement.
+  */
+  sqlite3SrcListAssignCursors(pParse, p->pSrc);
+
+  /* Look up every table named in the FROM clause of the select.  If
+  ** an entry of the FROM clause is a subquery instead of a table or view,
+  ** then create a transient table structure to describe the subquery.
+  */
+  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+    Table *pTab;
+    if( pFrom->pTab!=0 ){
+      /* This statement has already been prepared.  There is no need
+      ** to go further. */
+      assert( i==0 );
+      return 0;
+    }
+    if( pFrom->zName==0 ){
+#ifndef SQLITE_OMIT_SUBQUERY
+      /* A sub-query in the FROM clause of a SELECT */
+      assert( pFrom->pSelect!=0 );
+      if( pFrom->zAlias==0 ){
+        pFrom->zAlias =
+          sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pFrom->pSelect);
+      }
+      assert( pFrom->pTab==0 );
+      pFrom->pTab = pTab = 
+        sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
+      if( pTab==0 ){
+        return 1;
+      }
+      /* The isEphem flag indicates that the Table structure has been
+      ** dynamically allocated and may be freed at any time.  In other words,
+      ** pTab is not pointing to a persistent table structure that defines
+      ** part of the schema. */
+      pTab->isEphem = 1;
+#endif
+    }else{
+      /* An ordinary table or view name in the FROM clause */
+      assert( pFrom->pTab==0 );
+      pFrom->pTab = pTab = 
+        sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);
+      if( pTab==0 ){
+        return 1;
+      }
+      pTab->nRef++;
+#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
+      if( pTab->pSelect || IsVirtual(pTab) ){
+        /* We reach here if the named table is a really a view */
+        if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+          return 1;
+        }
+        /* If pFrom->pSelect!=0 it means we are dealing with a
+        ** view within a view.  The SELECT structure has already been
+        ** copied by the outer view so we can skip the copy step here
+        ** in the inner view.
+        */
+        if( pFrom->pSelect==0 ){
+          pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect);
+        }
+      }
+#endif
+    }
+  }
+
+  /* Process NATURAL keywords, and ON and USING clauses of joins.
+  */
+  if( sqliteProcessJoin(pParse, p) ) return 1;
+
+  /* For every "*" that occurs in the column list, insert the names of
+  ** all columns in all tables.  And for every TABLE.* insert the names
+  ** of all columns in TABLE.  The parser inserted a special expression
+  ** with the TK_ALL operator for each "*" that it found in the column list.
+  ** The following code just has to locate the TK_ALL expressions and expand
+  ** each one to the list of all columns in all tables.
+  **
+  ** The first loop just checks to see if there are any "*" operators
+  ** that need expanding.
+  */
+  for(k=0; k<pEList->nExpr; k++){
+    Expr *pE = pEList->a[k].pExpr;
+    if( pE->op==TK_ALL ) break;
+    if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
+         && pE->pLeft && pE->pLeft->op==TK_ID ) break;
+  }
+  rc = 0;
+  if( k<pEList->nExpr ){
+    /*
+    ** If we get here it means the result set contains one or more "*"
+    ** operators that need to be expanded.  Loop through each expression
+    ** in the result set and expand them one by one.
+    */
+    struct ExprList_item *a = pEList->a;
+    ExprList *pNew = 0;
+    int flags = pParse->db->flags;
+    int longNames = (flags & SQLITE_FullColNames)!=0 &&
+                      (flags & SQLITE_ShortColNames)==0;
+
+    for(k=0; k<pEList->nExpr; k++){
+      Expr *pE = a[k].pExpr;
+      if( pE->op!=TK_ALL &&
+           (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
+        /* This particular expression does not need to be expanded.
+        */
+        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr, 0);
+        if( pNew ){
+          pNew->a[pNew->nExpr-1].zName = a[k].zName;
+        }else{
+          rc = 1;
+        }
+        a[k].pExpr = 0;
+        a[k].zName = 0;
+      }else{
+        /* This expression is a "*" or a "TABLE.*" and needs to be
+        ** expanded. */
+        int tableSeen = 0;      /* Set to 1 when TABLE matches */
+        char *zTName;            /* text of name of TABLE */
+        if( pE->op==TK_DOT && pE->pLeft ){
+          zTName = sqlite3NameFromToken(db, &pE->pLeft->token);
+        }else{
+          zTName = 0;
+        }
+        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+          Table *pTab = pFrom->pTab;
+          char *zTabName = pFrom->zAlias;
+          if( zTabName==0 || zTabName[0]==0 ){ 
+            zTabName = pTab->zName;
+          }
+          if( zTName && (zTabName==0 || zTabName[0]==0 || 
+                 sqlite3StrICmp(zTName, zTabName)!=0) ){
+            continue;
+          }
+          tableSeen = 1;
+          for(j=0; j<pTab->nCol; j++){
+            Expr *pExpr, *pRight;
+            char *zName = pTab->aCol[j].zName;
+
+            /* If a column is marked as 'hidden' (currently only possible
+            ** for virtual tables), do not include it in the expanded
+            ** result-set list.
+            */
+            if( IsHiddenColumn(&pTab->aCol[j]) ){
+              assert(IsVirtual(pTab));
+              continue;
+            }
+
+            if( i>0 ){
+              struct SrcList_item *pLeft = &pTabList->a[i-1];
+              if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
+                        columnIndex(pLeft->pTab, zName)>=0 ){
+                /* In a NATURAL join, omit the join columns from the 
+                ** table on the right */
+                continue;
+              }
+              if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
+                /* In a join with a USING clause, omit columns in the
+                ** using clause from the table on the right. */
+                continue;
+              }
+            }
+            pRight = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
+            if( pRight==0 ) break;
+            setQuotedToken(pParse, &pRight->token, zName);
+            if( zTabName && (longNames || pTabList->nSrc>1) ){
+              Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
+              pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
+              if( pExpr==0 ) break;
+              setQuotedToken(pParse, &pLeft->token, zTabName);
+              setToken(&pExpr->span, 
+                  sqlite3MPrintf(db, "%s.%s", zTabName, zName));
+              pExpr->span.dyn = 1;
+              pExpr->token.z = 0;
+              pExpr->token.n = 0;
+              pExpr->token.dyn = 0;
+            }else{
+              pExpr = pRight;
+              pExpr->span = pExpr->token;
+              pExpr->span.dyn = 0;
+            }
+            if( longNames ){
+              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pExpr->span);
+            }else{
+              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pRight->token);
+            }
+          }
+        }
+        if( !tableSeen ){
+          if( zTName ){
+            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
+          }else{
+            sqlite3ErrorMsg(pParse, "no tables specified");
+          }
+          rc = 1;
+        }
+        sqlite3_free(zTName);
+      }
+    }
+    sqlite3ExprListDelete(pEList);
+    p->pEList = pNew;
+  }
+#if SQLITE_MAX_COLUMN
+  if( p->pEList && p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns in result set");
+    rc = SQLITE_ERROR;
+  }
+#endif
+  if( db->mallocFailed ){
+    rc = SQLITE_NOMEM;
+  }
+  return rc;
+}
+
+/*
+** pE is a pointer to an expression which is a single term in
+** ORDER BY or GROUP BY clause.
+**
+** If pE evaluates to an integer constant i, then return i.
+** This is an indication to the caller that it should sort
+** by the i-th column of the result set.
+**
+** If pE is a well-formed expression and the SELECT statement
+** is not compound, then return 0.  This indicates to the
+** caller that it should sort by the value of the ORDER BY
+** expression.
+**
+** If the SELECT is compound, then attempt to match pE against
+** result set columns in the left-most SELECT statement.  Return
+** the index i of the matching column, as an indication to the 
+** caller that it should sort by the i-th column.  If there is
+** no match, return -1 and leave an error message in pParse.
+*/
+static int matchOrderByTermToExprList(
+  Parse *pParse,     /* Parsing context for error messages */
+  Select *pSelect,   /* The SELECT statement with the ORDER BY clause */
+  Expr *pE,          /* The specific ORDER BY term */
+  int idx,           /* When ORDER BY term is this */
+  int isCompound,    /* True if this is a compound SELECT */
+  u8 *pHasAgg        /* True if expression contains aggregate functions */
+){
+  int i;             /* Loop counter */
+  ExprList *pEList;  /* The columns of the result set */
+  NameContext nc;    /* Name context for resolving pE */
+
+
+  /* If the term is an integer constant, return the value of that
+  ** constant */
+  pEList = pSelect->pEList;
+  if( sqlite3ExprIsInteger(pE, &i) ){
+    if( i<=0 ){
+      /* If i is too small, make it too big.  That way the calling
+      ** function still sees a value that is out of range, but does
+      ** not confuse the column number with 0 or -1 result code.
+      */
+      i = pEList->nExpr+1;
+    }
+    return i;
+  }
+
+  /* If the term is a simple identifier that try to match that identifier
+  ** against a column name in the result set.
+  */
+  if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){
+    sqlite3 *db = pParse->db;
+    char *zCol = sqlite3NameFromToken(db, &pE->token);
+    if( zCol==0 ){
+      return -1;
+    }
+    for(i=0; i<pEList->nExpr; i++){
+      char *zAs = pEList->a[i].zName;
+      if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
+        sqlite3_free(zCol);
+        return i+1;
+      }
+    }
+    sqlite3_free(zCol);
+  }
+
+  /* Resolve all names in the ORDER BY term expression
+  */
+  memset(&nc, 0, sizeof(nc));
+  nc.pParse = pParse;
+  nc.pSrcList = pSelect->pSrc;
+  nc.pEList = pEList;
+  nc.allowAgg = 1;
+  nc.nErr = 0;
+  if( sqlite3ExprResolveNames(&nc, pE) ){
+    if( isCompound ){
+      sqlite3ErrorClear(pParse);
+      return 0;
+    }else{
+      return -1;
+    }
+  }
+  if( nc.hasAgg && pHasAgg ){
+    *pHasAgg = 1;
+  }
+
+  /* For a compound SELECT, we need to try to match the ORDER BY
+  ** expression against an expression in the result set
+  */
+  if( isCompound ){
+    for(i=0; i<pEList->nExpr; i++){
+      if( sqlite3ExprCompare(pEList->a[i].pExpr, pE) ){
+        return i+1;
+      }
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Analyze and ORDER BY or GROUP BY clause in a simple SELECT statement.
+** Return the number of errors seen.
+**
+** Every term of the ORDER BY or GROUP BY clause needs to be an
+** expression.  If any expression is an integer constant, then
+** that expression is replaced by the corresponding 
+** expression from the result set.
+*/
+static int processOrderGroupBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect,      /* The SELECT statement containing the clause */
+  ExprList *pOrderBy,   /* The ORDER BY or GROUP BY clause to be processed */
+  int isOrder,          /* 1 for ORDER BY.  0 for GROUP BY */
+  u8 *pHasAgg           /* Set to TRUE if any term contains an aggregate */
+){
+  int i;
+  sqlite3 *db = pParse->db;
+  ExprList *pEList;
+
+  if( pOrderBy==0 || pParse->db->mallocFailed ) return 0;
+#if SQLITE_MAX_COLUMN
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    const char *zType = isOrder ? "ORDER" : "GROUP";
+    sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
+    return 1;
+  }
+#endif
+  pEList = pSelect->pEList;
+  if( pEList==0 ){
+    return 0;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    int iCol;
+    Expr *pE = pOrderBy->a[i].pExpr;
+    iCol = matchOrderByTermToExprList(pParse, pSelect, pE, i+1, 0, pHasAgg);
+    if( iCol<0 ){
+      return 1;
+    }
+    if( iCol>pEList->nExpr ){
+      const char *zType = isOrder ? "ORDER" : "GROUP";
+      sqlite3ErrorMsg(pParse, 
+         "%r %s BY term out of range - should be "
+         "between 1 and %d", i+1, zType, pEList->nExpr);
+      return 1;
+    }
+    if( iCol>0 ){
+      CollSeq *pColl = pE->pColl;
+      int flags = pE->flags & EP_ExpCollate;
+      sqlite3ExprDelete(pE);
+      pE = sqlite3ExprDup(db, pEList->a[iCol-1].pExpr);
+      pOrderBy->a[i].pExpr = pE;
+      if( pE && pColl && flags ){
+        pE->pColl = pColl;
+        pE->flags |= flags;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Analyze and ORDER BY or GROUP BY clause in a SELECT statement.  Return
+** the number of errors seen.
+**
+** The processing depends on whether the SELECT is simple or compound.
+** For a simple SELECT statement, evry term of the ORDER BY or GROUP BY
+** clause needs to be an expression.  If any expression is an integer
+** constant, then that expression is replaced by the corresponding 
+** expression from the result set.
+**
+** For compound SELECT statements, every expression needs to be of
+** type TK_COLUMN with a iTable value as given in the 4th parameter.
+** If any expression is an integer, that becomes the column number.
+** Otherwise, match the expression against result set columns from
+** the left-most SELECT.
+*/
+static int processCompoundOrderBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect,      /* The SELECT statement containing the ORDER BY */
+  int iTable            /* Output table for compound SELECT statements */
+){
+  int i;
+  ExprList *pOrderBy;
+  ExprList *pEList;
+  sqlite3 *db;
+  int moreToDo = 1;
+
+  pOrderBy = pSelect->pOrderBy;
+  if( pOrderBy==0 ) return 0;
+  db = pParse->db;
+#if SQLITE_MAX_COLUMN
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
+    return 1;
+  }
+#endif
+  for(i=0; i<pOrderBy->nExpr; i++){
+    pOrderBy->a[i].done = 0;
+  }
+  while( pSelect->pPrior ){
+    pSelect = pSelect->pPrior;
+  }
+  while( pSelect && moreToDo ){
+    moreToDo = 0;
+    for(i=0; i<pOrderBy->nExpr; i++){
+      int iCol = -1;
+      Expr *pE, *pDup;
+      if( pOrderBy->a[i].done ) continue;
+      pE = pOrderBy->a[i].pExpr;
+      pDup = sqlite3ExprDup(db, pE);
+      if( !db->mallocFailed ){
+        assert(pDup);
+        iCol = matchOrderByTermToExprList(pParse, pSelect, pDup, i+1, 1, 0);
+      }
+      sqlite3ExprDelete(pDup);
+      if( iCol<0 ){
+        return 1;
+      }
+      pEList = pSelect->pEList;
+      if( pEList==0 ){
+        return 1;
+      }
+      if( iCol>pEList->nExpr ){
+        sqlite3ErrorMsg(pParse, 
+           "%r ORDER BY term out of range - should be "
+           "between 1 and %d", i+1, pEList->nExpr);
+        return 1;
+      }
+      if( iCol>0 ){
+        pE->op = TK_COLUMN;
+        pE->iTable = iTable;
+        pE->iAgg = -1;
+        pE->iColumn = iCol-1;
+        pE->pTab = 0;
+        pOrderBy->a[i].done = 1;
+      }else{
+        moreToDo = 1;
+      }
+    }
+    pSelect = pSelect->pNext;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    if( pOrderBy->a[i].done==0 ){
+      sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
+            "column in the result set", i+1);
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Get a VDBE for the given parser context.  Create a new one if necessary.
+** If an error occurs, return NULL and leave a message in pParse.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse *pParse){
+  Vdbe *v = pParse->pVdbe;
+  if( v==0 ){
+    v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
+#ifndef SQLITE_OMIT_TRACE
+    if( v ){
+      sqlite3VdbeAddOp0(v, OP_Trace);
+    }
+#endif
+  }
+  return v;
+}
+
+
+/*
+** Compute the iLimit and iOffset fields of the SELECT based on the
+** pLimit and pOffset expressions.  pLimit and pOffset hold the expressions
+** that appear in the original SQL statement after the LIMIT and OFFSET
+** keywords.  Or NULL if those keywords are omitted. iLimit and iOffset 
+** are the integer memory register numbers for counters used to compute 
+** the limit and offset.  If there is no limit and/or offset, then 
+** iLimit and iOffset are negative.
+**
+** This routine changes the values of iLimit and iOffset only if
+** a limit or offset is defined by pLimit and pOffset.  iLimit and
+** iOffset should have been preset to appropriate default values
+** (usually but not always -1) prior to calling this routine.
+** Only if pLimit!=0 or pOffset!=0 do the limit registers get
+** redefined.  The UNION ALL operator uses this property to force
+** the reuse of the same limit and offset registers across multiple
+** SELECT statements.
+*/
+static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
+  Vdbe *v = 0;
+  int iLimit = 0;
+  int iOffset;
+  int addr1;
+
+  /* 
+  ** "LIMIT -1" always shows all rows.  There is some
+  ** contraversy about what the correct behavior should be.
+  ** The current implementation interprets "LIMIT 0" to mean
+  ** no rows.
+  */
+  if( p->pLimit ){
+    p->iLimit = iLimit = ++pParse->nMem;
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) return;
+    sqlite3ExprCode(pParse, p->pLimit, iLimit);
+    sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
+    VdbeComment((v, "LIMIT counter"));
+    sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
+  }
+  if( p->pOffset ){
+    p->iOffset = iOffset = ++pParse->nMem;
+    if( p->pLimit ){
+      pParse->nMem++;   /* Allocate an extra register for limit+offset */
+    }
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) return;
+    sqlite3ExprCode(pParse, p->pOffset, iOffset);
+    sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
+    VdbeComment((v, "OFFSET counter"));
+    addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
+    sqlite3VdbeJumpHere(v, addr1);
+    if( p->pLimit ){
+      sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
+      VdbeComment((v, "LIMIT+OFFSET"));
+      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
+      sqlite3VdbeJumpHere(v, addr1);
+    }
+  }
+}
+
+/*
+** Allocate a virtual index to use for sorting.
+*/
+static void createSortingIndex(Parse *pParse, Select *p, ExprList *pOrderBy){
+  if( pOrderBy ){
+    int addr;
+    assert( pOrderBy->iECursor==0 );
+    pOrderBy->iECursor = pParse->nTab++;
+    addr = sqlite3VdbeAddOp2(pParse->pVdbe, OP_OpenEphemeral,
+                            pOrderBy->iECursor, pOrderBy->nExpr+1);
+    assert( p->addrOpenEphm[2] == -1 );
+    p->addrOpenEphm[2] = addr;
+  }
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Return the appropriate collating sequence for the iCol-th column of
+** the result set for the compound-select statement "p".  Return NULL if
+** the column has no default collating sequence.
+**
+** The collating sequence for the compound select is taken from the
+** left-most term of the select that has a collating sequence.
+*/
+static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
+  CollSeq *pRet;
+  if( p->pPrior ){
+    pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
+  }else{
+    pRet = 0;
+  }
+  if( pRet==0 ){
+    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
+  }
+  return pRet;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** This routine is called to process a query that is really the union
+** or intersection of two or more separate queries.
+**
+** "p" points to the right-most of the two queries.  the query on the
+** left is p->pPrior.  The left query could also be a compound query
+** in which case this routine will be called recursively. 
+**
+** The results of the total query are to be written into a destination
+** of type eDest with parameter iParm.
+**
+** Example 1:  Consider a three-way compound SQL statement.
+**
+**     SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
+**
+** This statement is parsed up as follows:
+**
+**     SELECT c FROM t3
+**      |
+**      `----->  SELECT b FROM t2
+**                |
+**                `------>  SELECT a FROM t1
+**
+** The arrows in the diagram above represent the Select.pPrior pointer.
+** So if this routine is called with p equal to the t3 query, then
+** pPrior will be the t2 query.  p->op will be TK_UNION in this case.
+**
+** Notice that because of the way SQLite parses compound SELECTs, the
+** individual selects always group from left to right.
+*/
+static int multiSelect(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest,    /* What to do with query results */
+  char *aff             /* If eDest is SRT_Union, the affinity string */
+){
+  int rc = SQLITE_OK;   /* Success code from a subroutine */
+  Select *pPrior;       /* Another SELECT immediately to our left */
+  Vdbe *v;              /* Generate code to this VDBE */
+  int nCol;             /* Number of columns in the result set */
+  ExprList *pOrderBy;   /* The ORDER BY clause on p */
+  int aSetP2[2];        /* Set P2 value of these op to number of columns */
+  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
+  SelectDest dest;      /* Alternative data destination */
+
+  dest = *pDest;
+
+  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
+  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
+  */
+  if( p==0 || p->pPrior==0 ){
+    rc = 1;
+    goto multi_select_end;
+  }
+  pPrior = p->pPrior;
+  assert( pPrior->pRightmost!=pPrior );
+  assert( pPrior->pRightmost==p->pRightmost );
+  if( pPrior->pOrderBy ){
+    sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
+      selectOpName(p->op));
+    rc = 1;
+    goto multi_select_end;
+  }
+  if( pPrior->pLimit ){
+    sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
+      selectOpName(p->op));
+    rc = 1;
+    goto multi_select_end;
+  }
+
+  /* Make sure we have a valid query engine.  If not, create a new one.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    rc = 1;
+    goto multi_select_end;
+  }
+
+  /* Create the destination temporary table if necessary
+  */
+  if( dest.eDest==SRT_EphemTab ){
+    assert( p->pEList );
+    assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
+    aSetP2[nSetP2++] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, 0);
+    dest.eDest = SRT_Table;
+  }
+
+  /* Generate code for the left and right SELECT statements.
+  */
+  pOrderBy = p->pOrderBy;
+  switch( p->op ){
+    case TK_ALL: {
+      if( pOrderBy==0 ){
+        int addr = 0;
+        assert( !pPrior->pLimit );
+        pPrior->pLimit = p->pLimit;
+        pPrior->pOffset = p->pOffset;
+        rc = sqlite3Select(pParse, pPrior, &dest, 0, 0, 0, aff);
+        p->pLimit = 0;
+        p->pOffset = 0;
+        if( rc ){
+          goto multi_select_end;
+        }
+        p->pPrior = 0;
+        p->iLimit = pPrior->iLimit;
+        p->iOffset = pPrior->iOffset;
+        if( p->iLimit>=0 ){
+          addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
+          VdbeComment((v, "Jump ahead if LIMIT reached"));
+        }
+        rc = sqlite3Select(pParse, p, &dest, 0, 0, 0, aff);
+        p->pPrior = pPrior;
+        if( rc ){
+          goto multi_select_end;
+        }
+        if( addr ){
+          sqlite3VdbeJumpHere(v, addr);
+        }
+        break;
+      }
+      /* For UNION ALL ... ORDER BY fall through to the next case */
+    }
+    case TK_EXCEPT:
+    case TK_UNION: {
+      int unionTab;    /* Cursor number of the temporary table holding result */
+      int op = 0;      /* One of the SRT_ operations to apply to self */
+      int priorOp;     /* The SRT_ operation to apply to prior selects */
+      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
+      int addr;
+      SelectDest uniondest;
+
+      priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
+      if( dest.eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
+        /* We can reuse a temporary table generated by a SELECT to our
+        ** right.
+        */
+        unionTab = dest.iParm;
+      }else{
+        /* We will need to create our own temporary table to hold the
+        ** intermediate results.
+        */
+        unionTab = pParse->nTab++;
+        if( processCompoundOrderBy(pParse, p, unionTab) ){
+          rc = 1;
+          goto multi_select_end;
+        }
+        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
+        if( priorOp==SRT_Table ){
+          assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
+          aSetP2[nSetP2++] = addr;
+        }else{
+          assert( p->addrOpenEphm[0] == -1 );
+          p->addrOpenEphm[0] = addr;
+          p->pRightmost->usesEphm = 1;
+        }
+        createSortingIndex(pParse, p, pOrderBy);
+        assert( p->pEList );
+      }
+
+      /* Code the SELECT statements to our left
+      */
+      assert( !pPrior->pOrderBy );
+      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+      rc = sqlite3Select(pParse, pPrior, &uniondest, 0, 0, 0, aff);
+      if( rc ){
+        goto multi_select_end;
+      }
+
+      /* Code the current SELECT statement
+      */
+      switch( p->op ){
+         case TK_EXCEPT:  op = SRT_Except;   break;
+         case TK_UNION:   op = SRT_Union;    break;
+         case TK_ALL:     op = SRT_Table;    break;
+      }
+      p->pPrior = 0;
+      p->pOrderBy = 0;
+      p->disallowOrderBy = pOrderBy!=0;
+      pLimit = p->pLimit;
+      p->pLimit = 0;
+      pOffset = p->pOffset;
+      p->pOffset = 0;
+      uniondest.eDest = op;
+      rc = sqlite3Select(pParse, p, &uniondest, 0, 0, 0, aff);
+      /* Query flattening in sqlite3Select() might refill p->pOrderBy.
+      ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
+      sqlite3ExprListDelete(p->pOrderBy);
+      p->pPrior = pPrior;
+      p->pOrderBy = pOrderBy;
+      sqlite3ExprDelete(p->pLimit);
+      p->pLimit = pLimit;
+      p->pOffset = pOffset;
+      p->iLimit = -1;
+      p->iOffset = -1;
+      if( rc ){
+        goto multi_select_end;
+      }
+
+
+      /* Convert the data in the temporary table into whatever form
+      ** it is that we currently need.
+      */      
+      if( dest.eDest!=priorOp || unionTab!=dest.iParm ){
+        int iCont, iBreak, iStart;
+        assert( p->pEList );
+        if( dest.eDest==SRT_Callback ){
+          Select *pFirst = p;
+          while( pFirst->pPrior ) pFirst = pFirst->pPrior;
+          generateColumnNames(pParse, 0, pFirst->pEList);
+        }
+        iBreak = sqlite3VdbeMakeLabel(v);
+        iCont = sqlite3VdbeMakeLabel(v);
+        computeLimitRegisters(pParse, p, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
+        iStart = sqlite3VdbeCurrentAddr(v);
+        selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
+                        pOrderBy, -1, &dest, iCont, iBreak, 0);
+        sqlite3VdbeResolveLabel(v, iCont);
+        sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
+        sqlite3VdbeResolveLabel(v, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
+      }
+      break;
+    }
+    case TK_INTERSECT: {
+      int tab1, tab2;
+      int iCont, iBreak, iStart;
+      Expr *pLimit, *pOffset;
+      int addr;
+      SelectDest intersectdest;
+      int r1;
+
+      /* INTERSECT is different from the others since it requires
+      ** two temporary tables.  Hence it has its own case.  Begin
+      ** by allocating the tables we will need.
+      */
+      tab1 = pParse->nTab++;
+      tab2 = pParse->nTab++;
+      if( processCompoundOrderBy(pParse, p, tab1) ){
+        rc = 1;
+        goto multi_select_end;
+      }
+      createSortingIndex(pParse, p, pOrderBy);
+
+      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
+      assert( p->addrOpenEphm[0] == -1 );
+      p->addrOpenEphm[0] = addr;
+      p->pRightmost->usesEphm = 1;
+      assert( p->pEList );
+
+      /* Code the SELECTs to our left into temporary table "tab1".
+      */
+      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+      rc = sqlite3Select(pParse, pPrior, &intersectdest, 0, 0, 0, aff);
+      if( rc ){
+        goto multi_select_end;
+      }
+
+      /* Code the current SELECT into temporary table "tab2"
+      */
+      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
+      assert( p->addrOpenEphm[1] == -1 );
+      p->addrOpenEphm[1] = addr;
+      p->pPrior = 0;
+      pLimit = p->pLimit;
+      p->pLimit = 0;
+      pOffset = p->pOffset;
+      p->pOffset = 0;
+      intersectdest.iParm = tab2;
+      rc = sqlite3Select(pParse, p, &intersectdest, 0, 0, 0, aff);
+      p->pPrior = pPrior;
+      sqlite3ExprDelete(p->pLimit);
+      p->pLimit = pLimit;
+      p->pOffset = pOffset;
+      if( rc ){
+        goto multi_select_end;
+      }
+
+      /* Generate code to take the intersection of the two temporary
+      ** tables.
+      */
+      assert( p->pEList );
+      if( dest.eDest==SRT_Callback ){
+        Select *pFirst = p;
+        while( pFirst->pPrior ) pFirst = pFirst->pPrior;
+        generateColumnNames(pParse, 0, pFirst->pEList);
+      }
+      iBreak = sqlite3VdbeMakeLabel(v);
+      iCont = sqlite3VdbeMakeLabel(v);
+      computeLimitRegisters(pParse, p, iBreak);
+      sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
+      r1 = sqlite3GetTempReg(pParse);
+      iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
+      sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
+      sqlite3ReleaseTempReg(pParse, r1);
+      selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
+                      pOrderBy, -1, &dest, iCont, iBreak, 0);
+      sqlite3VdbeResolveLabel(v, iCont);
+      sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
+      sqlite3VdbeResolveLabel(v, iBreak);
+      sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
+      sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
+      break;
+    }
+  }
+
+  /* Make sure all SELECTs in the statement have the same number of elements
+  ** in their result sets.
+  */
+  assert( p->pEList && pPrior->pEList );
+  if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
+    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+      " do not have the same number of result columns", selectOpName(p->op));
+    rc = 1;
+    goto multi_select_end;
+  }
+
+  /* Set the number of columns in temporary tables
+  */
+  nCol = p->pEList->nExpr;
+  while( nSetP2 ){
+    sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
+  }
+
+  /* Compute collating sequences used by either the ORDER BY clause or
+  ** by any temporary tables needed to implement the compound select.
+  ** Attach the KeyInfo structure to all temporary tables.  Invoke the
+  ** ORDER BY processing if there is an ORDER BY clause.
+  **
+  ** This section is run by the right-most SELECT statement only.
+  ** SELECT statements to the left always skip this part.  The right-most
+  ** SELECT might also skip this part if it has no ORDER BY clause and
+  ** no temp tables are required.
+  */
+  if( pOrderBy || p->usesEphm ){
+    int i;                        /* Loop counter */
+    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
+    Select *pLoop;                /* For looping through SELECT statements */
+    int nKeyCol;                  /* Number of entries in pKeyInfo->aCol[] */
+    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
+    CollSeq **aCopy;              /* A copy of pKeyInfo->aColl[] */
+
+    assert( p->pRightmost==p );
+    nKeyCol = nCol + (pOrderBy ? pOrderBy->nExpr : 0);
+    pKeyInfo = sqlite3DbMallocZero(pParse->db,
+                       sizeof(*pKeyInfo)+nKeyCol*(sizeof(CollSeq*) + 1));
+    if( !pKeyInfo ){
+      rc = SQLITE_NOMEM;
+      goto multi_select_end;
+    }
+
+    pKeyInfo->enc = ENC(pParse->db);
+    pKeyInfo->nField = nCol;
+
+    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
+      *apColl = multiSelectCollSeq(pParse, p, i);
+      if( 0==*apColl ){
+        *apColl = pParse->db->pDfltColl;
+      }
+    }
+
+    for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
+      for(i=0; i<2; i++){
+        int addr = pLoop->addrOpenEphm[i];
+        if( addr<0 ){
+          /* If [0] is unused then [1] is also unused.  So we can
+          ** always safely abort as soon as the first unused slot is found */
+          assert( pLoop->addrOpenEphm[1]<0 );
+          break;
+        }
+        sqlite3VdbeChangeP2(v, addr, nCol);
+        sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
+        pLoop->addrOpenEphm[i] = -1;
+      }
+    }
+
+    if( pOrderBy ){
+      struct ExprList_item *pOTerm = pOrderBy->a;
+      int nOrderByExpr = pOrderBy->nExpr;
+      int addr;
+      u8 *pSortOrder;
+
+      /* Reuse the same pKeyInfo for the ORDER BY as was used above for
+      ** the compound select statements.  Except we have to change out the
+      ** pKeyInfo->aColl[] values.  Some of the aColl[] values will be
+      ** reused when constructing the pKeyInfo for the ORDER BY, so make
+      ** a copy.  Sufficient space to hold both the nCol entries for
+      ** the compound select and the nOrderbyExpr entries for the ORDER BY
+      ** was allocated above.  But we need to move the compound select
+      ** entries out of the way before constructing the ORDER BY entries.
+      ** Move the compound select entries into aCopy[] where they can be
+      ** accessed and reused when constructing the ORDER BY entries.
+      ** Because nCol might be greater than or less than nOrderByExpr
+      ** we have to use memmove() when doing the copy.
+      */
+      aCopy = &pKeyInfo->aColl[nOrderByExpr];
+      pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
+      memmove(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));
+
+      apColl = pKeyInfo->aColl;
+      for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
+        Expr *pExpr = pOTerm->pExpr;
+        if( (pExpr->flags & EP_ExpCollate) ){
+          assert( pExpr->pColl!=0 );
+          *apColl = pExpr->pColl;
+        }else{
+          *apColl = aCopy[pExpr->iColumn];
+        }
+        *pSortOrder = pOTerm->sortOrder;
+      }
+      assert( p->pRightmost==p );
+      assert( p->addrOpenEphm[2]>=0 );
+      addr = p->addrOpenEphm[2];
+      sqlite3VdbeChangeP2(v, addr, p->pOrderBy->nExpr+2);
+      pKeyInfo->nField = nOrderByExpr;
+      sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+      pKeyInfo = 0;
+      generateSortTail(pParse, p, v, p->pEList->nExpr, &dest);
+    }
+
+    sqlite3_free(pKeyInfo);
+  }
+
+multi_select_end:
+  pDest->iMem = dest.iMem;
+  pDest->nMem = dest.nMem;
+  return rc;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+#ifndef SQLITE_OMIT_VIEW
+/* Forward Declarations */
+static void substExprList(sqlite3*, ExprList*, int, ExprList*);
+static void substSelect(sqlite3*, Select *, int, ExprList *);
+
+/*
+** Scan through the expression pExpr.  Replace every reference to
+** a column in table number iTable with a copy of the iColumn-th
+** entry in pEList.  (But leave references to the ROWID column 
+** unchanged.)
+**
+** This routine is part of the flattening procedure.  A subquery
+** whose result set is defined by pEList appears as entry in the
+** FROM clause of a SELECT such that the VDBE cursor assigned to that
+** FORM clause entry is iTable.  This routine make the necessary 
+** changes to pExpr so that it refers directly to the source table
+** of the subquery rather the result set of the subquery.
+*/
+static void substExpr(
+  sqlite3 *db,        /* Report malloc errors to this connection */
+  Expr *pExpr,        /* Expr in which substitution occurs */
+  int iTable,         /* Table to be substituted */
+  ExprList *pEList    /* Substitute expressions */
+){
+  if( pExpr==0 ) return;
+  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
+    if( pExpr->iColumn<0 ){
+      pExpr->op = TK_NULL;
+    }else{
+      Expr *pNew;
+      assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
+      assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
+      pNew = pEList->a[pExpr->iColumn].pExpr;
+      assert( pNew!=0 );
+      pExpr->op = pNew->op;
+      assert( pExpr->pLeft==0 );
+      pExpr->pLeft = sqlite3ExprDup(db, pNew->pLeft);
+      assert( pExpr->pRight==0 );
+      pExpr->pRight = sqlite3ExprDup(db, pNew->pRight);
+      assert( pExpr->pList==0 );
+      pExpr->pList = sqlite3ExprListDup(db, pNew->pList);
+      pExpr->iTable = pNew->iTable;
+      pExpr->pTab = pNew->pTab;
+      pExpr->iColumn = pNew->iColumn;
+      pExpr->iAgg = pNew->iAgg;
+      sqlite3TokenCopy(db, &pExpr->token, &pNew->token);
+      sqlite3TokenCopy(db, &pExpr->span, &pNew->span);
+      pExpr->pSelect = sqlite3SelectDup(db, pNew->pSelect);
+      pExpr->flags = pNew->flags;
+    }
+  }else{
+    substExpr(db, pExpr->pLeft, iTable, pEList);
+    substExpr(db, pExpr->pRight, iTable, pEList);
+    substSelect(db, pExpr->pSelect, iTable, pEList);
+    substExprList(db, pExpr->pList, iTable, pEList);
+  }
+}
+static void substExprList(
+  sqlite3 *db,         /* Report malloc errors here */
+  ExprList *pList,     /* List to scan and in which to make substitutes */
+  int iTable,          /* Table to be substituted */
+  ExprList *pEList     /* Substitute values */
+){
+  int i;
+  if( pList==0 ) return;
+  for(i=0; i<pList->nExpr; i++){
+    substExpr(db, pList->a[i].pExpr, iTable, pEList);
+  }
+}
+static void substSelect(
+  sqlite3 *db,         /* Report malloc errors here */
+  Select *p,           /* SELECT statement in which to make substitutions */
+  int iTable,          /* Table to be replaced */
+  ExprList *pEList     /* Substitute values */
+){
+  if( !p ) return;
+  substExprList(db, p->pEList, iTable, pEList);
+  substExprList(db, p->pGroupBy, iTable, pEList);
+  substExprList(db, p->pOrderBy, iTable, pEList);
+  substExpr(db, p->pHaving, iTable, pEList);
+  substExpr(db, p->pWhere, iTable, pEList);
+  substSelect(db, p->pPrior, iTable, pEList);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) */
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** This routine attempts to flatten subqueries in order to speed
+** execution.  It returns 1 if it makes changes and 0 if no flattening
+** occurs.
+**
+** To understand the concept of flattening, consider the following
+** query:
+**
+**     SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
+**
+** The default way of implementing this query is to execute the
+** subquery first and store the results in a temporary table, then
+** run the outer query on that temporary table.  This requires two
+** passes over the data.  Furthermore, because the temporary table
+** has no indices, the WHERE clause on the outer query cannot be
+** optimized.
+**
+** This routine attempts to rewrite queries such as the above into
+** a single flat select, like this:
+**
+**     SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
+**
+** The code generated for this simpification gives the same result
+** but only has to scan the data once.  And because indices might 
+** exist on the table t1, a complete scan of the data might be
+** avoided.
+**
+** Flattening is only attempted if all of the following are true:
+**
+**   (1)  The subquery and the outer query do not both use aggregates.
+**
+**   (2)  The subquery is not an aggregate or the outer query is not a join.
+**
+**   (3)  The subquery is not the right operand of a left outer join, or
+**        the subquery is not itself a join.  (Ticket #306)
+**
+**   (4)  The subquery is not DISTINCT or the outer query is not a join.
+**
+**   (5)  The subquery is not DISTINCT or the outer query does not use
+**        aggregates.
+**
+**   (6)  The subquery does not use aggregates or the outer query is not
+**        DISTINCT.
+**
+**   (7)  The subquery has a FROM clause.
+**
+**   (8)  The subquery does not use LIMIT or the outer query is not a join.
+**
+**   (9)  The subquery does not use LIMIT or the outer query does not use
+**        aggregates.
+**
+**  (10)  The subquery does not use aggregates or the outer query does not
+**        use LIMIT.
+**
+**  (11)  The subquery and the outer query do not both have ORDER BY clauses.
+**
+**  (12)  The subquery is not the right term of a LEFT OUTER JOIN or the
+**        subquery has no WHERE clause.  (added by ticket #350)
+**
+**  (13)  The subquery and outer query do not both use LIMIT
+**
+**  (14)  The subquery does not use OFFSET
+**
+**  (15)  The outer query is not part of a compound select or the
+**        subquery does not have both an ORDER BY and a LIMIT clause.
+**        (See ticket #2339)
+**
+**  (16)  The outer query is not an aggregate or the subquery does
+**        not contain ORDER BY.  (Ticket #2942)  This used to not matter
+**        until we introduced the group_concat() function.  
+**
+** In this routine, the "p" parameter is a pointer to the outer query.
+** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
+** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
+**
+** If flattening is not attempted, this routine is a no-op and returns 0.
+** If flattening is attempted this routine returns 1.
+**
+** All of the expression analysis must occur on both the outer query and
+** the subquery before this routine runs.
+*/
+static int flattenSubquery(
+  sqlite3 *db,         /* Database connection */
+  Select *p,           /* The parent or outer SELECT statement */
+  int iFrom,           /* Index in p->pSrc->a[] of the inner subquery */
+  int isAgg,           /* True if outer SELECT uses aggregate functions */
+  int subqueryIsAgg    /* True if the subquery uses aggregate functions */
+){
+  Select *pSub;       /* The inner query or "subquery" */
+  SrcList *pSrc;      /* The FROM clause of the outer query */
+  SrcList *pSubSrc;   /* The FROM clause of the subquery */
+  ExprList *pList;    /* The result set of the outer query */
+  int iParent;        /* VDBE cursor number of the pSub result set temp table */
+  int i;              /* Loop counter */
+  Expr *pWhere;                    /* The WHERE clause */
+  struct SrcList_item *pSubitem;   /* The subquery */
+
+  /* Check to see if flattening is permitted.  Return 0 if not.
+  */
+  if( p==0 ) return 0;
+  pSrc = p->pSrc;
+  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
+  pSubitem = &pSrc->a[iFrom];
+  pSub = pSubitem->pSelect;
+  assert( pSub!=0 );
+  if( isAgg && subqueryIsAgg ) return 0;                 /* Restriction (1)  */
+  if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;          /* Restriction (2)  */
+  pSubSrc = pSub->pSrc;
+  assert( pSubSrc );
+  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
+  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
+  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
+  ** became arbitrary expressions, we were forced to add restrictions (13)
+  ** and (14). */
+  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
+  if( pSub->pOffset ) return 0;                          /* Restriction (14) */
+  if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
+    return 0;                                            /* Restriction (15) */
+  }
+  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
+  if( (pSub->isDistinct || pSub->pLimit) 
+         && (pSrc->nSrc>1 || isAgg) ){          /* Restrictions (4)(5)(8)(9) */
+     return 0;       
+  }
+  if( p->isDistinct && subqueryIsAgg ) return 0;         /* Restriction (6)  */
+  if( (p->disallowOrderBy || p->pOrderBy) && pSub->pOrderBy ){
+     return 0;                                           /* Restriction (11) */
+  }
+  if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
+
+  /* Restriction 3:  If the subquery is a join, make sure the subquery is 
+  ** not used as the right operand of an outer join.  Examples of why this
+  ** is not allowed:
+  **
+  **         t1 LEFT OUTER JOIN (t2 JOIN t3)
+  **
+  ** If we flatten the above, we would get
+  **
+  **         (t1 LEFT OUTER JOIN t2) JOIN t3
+  **
+  ** which is not at all the same thing.
+  */
+  if( pSubSrc->nSrc>1 && (pSubitem->jointype & JT_OUTER)!=0 ){
+    return 0;
+  }
+
+  /* Restriction 12:  If the subquery is the right operand of a left outer
+  ** join, make sure the subquery has no WHERE clause.
+  ** An examples of why this is not allowed:
+  **
+  **         t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
+  **
+  ** If we flatten the above, we would get
+  **
+  **         (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
+  **
+  ** But the t2.x>0 test will always fail on a NULL row of t2, which
+  ** effectively converts the OUTER JOIN into an INNER JOIN.
+  */
+  if( (pSubitem->jointype & JT_OUTER)!=0 && pSub->pWhere!=0 ){
+    return 0;
+  }
+
+  /* If we reach this point, it means flattening is permitted for the
+  ** iFrom-th entry of the FROM clause in the outer query.
+  */
+
+  /* Move all of the FROM elements of the subquery into the
+  ** the FROM clause of the outer query.  Before doing this, remember
+  ** the cursor number for the original outer query FROM element in
+  ** iParent.  The iParent cursor will never be used.  Subsequent code
+  ** will scan expressions looking for iParent references and replace
+  ** those references with expressions that resolve to the subquery FROM
+  ** elements we are now copying in.
+  */
+  iParent = pSubitem->iCursor;
+  {
+    int nSubSrc = pSubSrc->nSrc;
+    int jointype = pSubitem->jointype;
+
+    sqlite3DeleteTable(pSubitem->pTab);
+    sqlite3_free(pSubitem->zDatabase);
+    sqlite3_free(pSubitem->zName);
+    sqlite3_free(pSubitem->zAlias);
+    pSubitem->pTab = 0;
+    pSubitem->zDatabase = 0;
+    pSubitem->zName = 0;
+    pSubitem->zAlias = 0;
+    if( nSubSrc>1 ){
+      int extra = nSubSrc - 1;
+      for(i=1; i<nSubSrc; i++){
+        pSrc = sqlite3SrcListAppend(db, pSrc, 0, 0);
+        if( pSrc==0 ){
+          p->pSrc = 0;
+          return 1;
+        }
+      }
+      p->pSrc = pSrc;
+      for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
+        pSrc->a[i] = pSrc->a[i-extra];
+      }
+    }
+    for(i=0; i<nSubSrc; i++){
+      pSrc->a[i+iFrom] = pSubSrc->a[i];
+      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
+    }
+    pSrc->a[iFrom].jointype = jointype;
+  }
+
+  /* Now begin substituting subquery result set expressions for 
+  ** references to the iParent in the outer query.
+  ** 
+  ** Example:
+  **
+  **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
+  **   \                     \_____________ subquery __________/          /
+  **    \_____________________ outer query ______________________________/
+  **
+  ** We look at every expression in the outer query and every place we see
+  ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
+  */
+  pList = p->pEList;
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr;
+    if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
+      pList->a[i].zName = 
+             sqlite3DbStrNDup(db, (char*)pExpr->span.z, pExpr->span.n);
+    }
+  }
+  substExprList(db, p->pEList, iParent, pSub->pEList);
+  if( isAgg ){
+    substExprList(db, p->pGroupBy, iParent, pSub->pEList);
+    substExpr(db, p->pHaving, iParent, pSub->pEList);
+  }
+  if( pSub->pOrderBy ){
+    assert( p->pOrderBy==0 );
+    p->pOrderBy = pSub->pOrderBy;
+    pSub->pOrderBy = 0;
+  }else if( p->pOrderBy ){
+    substExprList(db, p->pOrderBy, iParent, pSub->pEList);
+  }
+  if( pSub->pWhere ){
+    pWhere = sqlite3ExprDup(db, pSub->pWhere);
+  }else{
+    pWhere = 0;
+  }
+  if( subqueryIsAgg ){
+    assert( p->pHaving==0 );
+    p->pHaving = p->pWhere;
+    p->pWhere = pWhere;
+    substExpr(db, p->pHaving, iParent, pSub->pEList);
+    p->pHaving = sqlite3ExprAnd(db, p->pHaving, 
+                                sqlite3ExprDup(db, pSub->pHaving));
+    assert( p->pGroupBy==0 );
+    p->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy);
+  }else{
+    substExpr(db, p->pWhere, iParent, pSub->pEList);
+    p->pWhere = sqlite3ExprAnd(db, p->pWhere, pWhere);
+  }
+
+  /* The flattened query is distinct if either the inner or the
+  ** outer query is distinct. 
+  */
+  p->isDistinct = p->isDistinct || pSub->isDistinct;
+
+  /*
+  ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
+  **
+  ** One is tempted to try to add a and b to combine the limits.  But this
+  ** does not work if either limit is negative.
+  */
+  if( pSub->pLimit ){
+    p->pLimit = pSub->pLimit;
+    pSub->pLimit = 0;
+  }
+
+  /* Finially, delete what is left of the subquery and return
+  ** success.
+  */
+  sqlite3SelectDelete(pSub);
+  return 1;
+}
+#endif /* SQLITE_OMIT_VIEW */
+
+/*
+** Analyze the SELECT statement passed as an argument to see if it
+** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if 
+** it is, or 0 otherwise. At present, a query is considered to be
+** a min()/max() query if:
+**
+**   1. There is a single object in the FROM clause.
+**
+**   2. There is a single expression in the result set, and it is
+**      either min(x) or max(x), where x is a column reference.
+*/
+static int minMaxQuery(Parse *pParse, Select *p){
+  Expr *pExpr;
+  ExprList *pEList = p->pEList;
+
+  if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
+  pExpr = pEList->a[0].pExpr;
+  pEList = pExpr->pList;
+  if( pExpr->op!=TK_AGG_FUNCTION || pEList==0 || pEList->nExpr!=1 ) return 0;
+  if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
+  if( pExpr->token.n!=3 ) return WHERE_ORDERBY_NORMAL;
+  if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
+    return WHERE_ORDERBY_MIN;
+  }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
+    return WHERE_ORDERBY_MAX;
+  }
+  return WHERE_ORDERBY_NORMAL;
+}
+
+/*
+** This routine resolves any names used in the result set of the
+** supplied SELECT statement. If the SELECT statement being resolved
+** is a sub-select, then pOuterNC is a pointer to the NameContext 
+** of the parent SELECT.
+*/
+SQLITE_PRIVATE int sqlite3SelectResolve(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  NameContext *pOuterNC  /* The outer name context. May be NULL. */
+){
+  ExprList *pEList;          /* Result set. */
+  int i;                     /* For-loop variable used in multiple places */
+  NameContext sNC;           /* Local name-context */
+  ExprList *pGroupBy;        /* The group by clause */
+
+  /* If this routine has run before, return immediately. */
+  if( p->isResolved ){
+    assert( !pOuterNC );
+    return SQLITE_OK;
+  }
+  p->isResolved = 1;
+
+  /* If there have already been errors, do nothing. */
+  if( pParse->nErr>0 ){
+    return SQLITE_ERROR;
+  }
+
+  /* Prepare the select statement. This call will allocate all cursors
+  ** required to handle the tables and subqueries in the FROM clause.
+  */
+  if( prepSelectStmt(pParse, p) ){
+    return SQLITE_ERROR;
+  }
+
+  /* Resolve the expressions in the LIMIT and OFFSET clauses. These
+  ** are not allowed to refer to any names, so pass an empty NameContext.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  if( sqlite3ExprResolveNames(&sNC, p->pLimit) ||
+      sqlite3ExprResolveNames(&sNC, p->pOffset) ){
+    return SQLITE_ERROR;
+  }
+
+  /* Set up the local name-context to pass to ExprResolveNames() to
+  ** resolve the expression-list.
+  */
+  sNC.allowAgg = 1;
+  sNC.pSrcList = p->pSrc;
+  sNC.pNext = pOuterNC;
+
+  /* Resolve names in the result set. */
+  pEList = p->pEList;
+  if( !pEList ) return SQLITE_ERROR;
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *pX = pEList->a[i].pExpr;
+    if( sqlite3ExprResolveNames(&sNC, pX) ){
+      return SQLITE_ERROR;
+    }
+  }
+
+  /* If there are no aggregate functions in the result-set, and no GROUP BY 
+  ** expression, do not allow aggregates in any of the other expressions.
+  */
+  assert( !p->isAgg );
+  pGroupBy = p->pGroupBy;
+  if( pGroupBy || sNC.hasAgg ){
+    p->isAgg = 1;
+  }else{
+    sNC.allowAgg = 0;
+  }
+
+  /* If a HAVING clause is present, then there must be a GROUP BY clause.
+  */
+  if( p->pHaving && !pGroupBy ){
+    sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
+    return SQLITE_ERROR;
+  }
+
+  /* Add the expression list to the name-context before parsing the
+  ** other expressions in the SELECT statement. This is so that
+  ** expressions in the WHERE clause (etc.) can refer to expressions by
+  ** aliases in the result set.
+  **
+  ** Minor point: If this is the case, then the expression will be
+  ** re-evaluated for each reference to it.
+  */
+  sNC.pEList = p->pEList;
+  if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
+     sqlite3ExprResolveNames(&sNC, p->pHaving) ){
+    return SQLITE_ERROR;
+  }
+  if( p->pPrior==0 ){
+    if( processOrderGroupBy(pParse, p, p->pOrderBy, 1, &sNC.hasAgg) ){
+      return SQLITE_ERROR;
+    }
+  }
+  if( processOrderGroupBy(pParse, p, pGroupBy, 0, &sNC.hasAgg) ){
+    return SQLITE_ERROR;
+  }
+
+  if( pParse->db->mallocFailed ){
+    return SQLITE_NOMEM;
+  }
+
+  /* Make sure the GROUP BY clause does not contain aggregate functions.
+  */
+  if( pGroupBy ){
+    struct ExprList_item *pItem;
+  
+    for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
+      if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
+        sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
+            "the GROUP BY clause");
+        return SQLITE_ERROR;
+      }
+    }
+  }
+
+  /* If this is one SELECT of a compound, be sure to resolve names
+  ** in the other SELECTs.
+  */
+  if( p->pPrior ){
+    return sqlite3SelectResolve(pParse, p->pPrior, pOuterNC);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Reset the aggregate accumulator.
+**
+** The aggregate accumulator is a set of memory cells that hold
+** intermediate results while calculating an aggregate.  This
+** routine simply stores NULLs in all of those memory cells.
+*/
+static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pFunc;
+  if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
+    return;
+  }
+  for(i=0; i<pAggInfo->nColumn; i++){
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pAggInfo->aCol[i].iMem);
+  }
+  for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
+    if( pFunc->iDistinct>=0 ){
+      Expr *pE = pFunc->pExpr;
+      if( pE->pList==0 || pE->pList->nExpr!=1 ){
+        sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
+           "by an expression");
+        pFunc->iDistinct = -1;
+      }else{
+        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
+        sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
+                          (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+      }
+    }
+  }
+}
+
+/*
+** Invoke the OP_AggFinalize opcode for every aggregate function
+** in the AggInfo structure.
+*/
+static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pF;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    ExprList *pList = pF->pExpr->pList;
+    sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
+                      (void*)pF->pFunc, P4_FUNCDEF);
+  }
+}
+
+/*
+** Update the accumulator memory cells for an aggregate based on
+** the current cursor position.
+*/
+static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pF;
+  struct AggInfo_col *pC;
+
+  pAggInfo->directMode = 1;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    int nArg;
+    int addrNext = 0;
+    int regAgg;
+    ExprList *pList = pF->pExpr->pList;
+    if( pList ){
+      nArg = pList->nExpr;
+      regAgg = sqlite3GetTempRange(pParse, nArg);
+      sqlite3ExprCodeExprList(pParse, pList, regAgg, 0);
+    }else{
+      nArg = 0;
+      regAgg = 0;
+    }
+    if( pF->iDistinct>=0 ){
+      addrNext = sqlite3VdbeMakeLabel(v);
+      assert( nArg==1 );
+      codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
+    }
+    if( pF->pFunc->needCollSeq ){
+      CollSeq *pColl = 0;
+      struct ExprList_item *pItem;
+      int j;
+      assert( pList!=0 );  /* pList!=0 if pF->pFunc->needCollSeq is true */
+      for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
+        pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+      }
+      if( !pColl ){
+        pColl = pParse->db->pDfltColl;
+      }
+      sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+    }
+    sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
+                      (void*)pF->pFunc, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, nArg);
+    sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+    sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
+    if( addrNext ){
+      sqlite3VdbeResolveLabel(v, addrNext);
+    }
+  }
+  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
+    sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
+  }
+  pAggInfo->directMode = 0;
+}
+
+#if 0
+/*
+** This function is used when a SELECT statement is used to create a
+** temporary table for iterating through when running an INSTEAD OF
+** UPDATE or INSTEAD OF DELETE trigger. 
+**
+** If possible, the SELECT statement is modified so that NULL values
+** are stored in the temporary table for all columns for which the 
+** corresponding bit in argument mask is not set. If mask takes the
+** special value 0xffffffff, then all columns are populated.
+*/
+SQLITE_PRIVATE void sqlite3SelectMask(Parse *pParse, Select *p, u32 mask){
+  if( p && !p->pPrior && !p->isDistinct && mask!=0xffffffff ){
+    ExprList *pEList;
+    int i;
+    sqlite3SelectResolve(pParse, p, 0);
+    pEList = p->pEList;
+    for(i=0; pEList && i<pEList->nExpr && i<32; i++){
+      if( !(mask&((u32)1<<i)) ){
+        sqlite3ExprDelete(pEList->a[i].pExpr);
+        pEList->a[i].pExpr = sqlite3Expr(pParse->db, TK_NULL, 0, 0, 0);
+      }
+    }
+  }
+}
+#endif
+
+/*
+** Generate code for the given SELECT statement.
+**
+** The results are distributed in various ways depending on the
+** contents of the SelectDest structure pointed to by argument pDest
+** as follows:
+**
+**     pDest->eDest    Result
+**     ------------    -------------------------------------------
+**     SRT_Callback    Invoke the callback for each row of the result.
+**
+**     SRT_Mem         Store first result in memory cell pDest->iParm
+**
+**     SRT_Set         Store non-null results as keys of table pDest->iParm. 
+**                     Apply the affinity pDest->affinity before storing them.
+**
+**     SRT_Union       Store results as a key in a temporary table pDest->iParm.
+**
+**     SRT_Except      Remove results from the temporary table pDest->iParm.
+**
+**     SRT_Table       Store results in temporary table pDest->iParm
+**
+**     SRT_EphemTab    Create an temporary table pDest->iParm and store
+**                     the result there. The cursor is left open after
+**                     returning.
+**
+**     SRT_Subroutine  For each row returned, push the results onto the
+**                     vdbe stack and call the subroutine (via OP_Gosub)
+**                     at address pDest->iParm.
+**
+**     SRT_Exists      Store a 1 in memory cell pDest->iParm if the result
+**                     set is not empty.
+**
+**     SRT_Discard     Throw the results away.
+**
+** See the selectInnerLoop() function for a canonical listing of the 
+** allowed values of eDest and their meanings.
+**
+** This routine returns the number of errors.  If any errors are
+** encountered, then an appropriate error message is left in
+** pParse->zErrMsg.
+**
+** This routine does NOT free the Select structure passed in.  The
+** calling function needs to do that.
+**
+** The pParent, parentTab, and *pParentAgg fields are filled in if this
+** SELECT is a subquery.  This routine may try to combine this SELECT
+** with its parent to form a single flat query.  In so doing, it might
+** change the parent query from a non-aggregate to an aggregate query.
+** For that reason, the pParentAgg flag is passed as a pointer, so it
+** can be changed.
+**
+** Example 1:   The meaning of the pParent parameter.
+**
+**    SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
+**    \                      \_______ subquery _______/        /
+**     \                                                      /
+**      \____________________ outer query ___________________/
+**
+** This routine is called for the outer query first.   For that call,
+** pParent will be NULL.  During the processing of the outer query, this 
+** routine is called recursively to handle the subquery.  For the recursive
+** call, pParent will point to the outer query.  Because the subquery is
+** the second element in a three-way join, the parentTab parameter will
+** be 1 (the 2nd value of a 0-indexed array.)
+*/
+SQLITE_PRIVATE int sqlite3Select(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  SelectDest *pDest,     /* What to do with the query results */
+  Select *pParent,       /* Another SELECT for which this is a sub-query */
+  int parentTab,         /* Index in pParent->pSrc of this query */
+  int *pParentAgg,       /* True if pParent uses aggregate functions */
+  char *aff              /* If eDest is SRT_Union, the affinity string */
+){
+  int i, j;              /* Loop counters */
+  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
+  Vdbe *v;               /* The virtual machine under construction */
+  int isAgg;             /* True for select lists like "count(*)" */
+  ExprList *pEList;      /* List of columns to extract. */
+  SrcList *pTabList;     /* List of tables to select from */
+  Expr *pWhere;          /* The WHERE clause.  May be NULL */
+  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
+  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
+  Expr *pHaving;         /* The HAVING clause.  May be NULL */
+  int isDistinct;        /* True if the DISTINCT keyword is present */
+  int distinct;          /* Table to use for the distinct set */
+  int rc = 1;            /* Value to return from this function */
+  int addrSortIndex;     /* Address of an OP_OpenEphemeral instruction */
+  AggInfo sAggInfo;      /* Information used by aggregate queries */
+  int iEnd;              /* Address of the end of the query */
+  sqlite3 *db;           /* The database connection */
+
+  db = pParse->db;
+  if( p==0 || db->mallocFailed || pParse->nErr ){
+    return 1;
+  }
+  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
+  memset(&sAggInfo, 0, sizeof(sAggInfo));
+
+  pOrderBy = p->pOrderBy;
+  if( IgnorableOrderby(pDest) ){
+    p->pOrderBy = 0;
+
+    /* In these cases the DISTINCT operator makes no difference to the
+    ** results, so remove it if it were specified.
+    */
+    assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union || 
+           pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard);
+    p->isDistinct = 0;
+  }
+  if( sqlite3SelectResolve(pParse, p, 0) ){
+    goto select_end;
+  }
+  p->pOrderBy = pOrderBy;
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+  /* If there is are a sequence of queries, do the earlier ones first.
+  */
+  if( p->pPrior ){
+    if( p->pRightmost==0 ){
+      Select *pLoop, *pRight = 0;
+      int cnt = 0;
+      int mxSelect;
+      for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
+        pLoop->pRightmost = p;
+        pLoop->pNext = pRight;
+        pRight = pLoop;
+      }
+      mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
+      if( mxSelect && cnt>mxSelect ){
+        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
+        return 1;
+      }
+    }
+    return multiSelect(pParse, p, pDest, aff);
+  }
+#endif
+
+  /* Make local copies of the parameters for this query.
+  */
+  pTabList = p->pSrc;
+  pWhere = p->pWhere;
+  pGroupBy = p->pGroupBy;
+  pHaving = p->pHaving;
+  isAgg = p->isAgg;
+  isDistinct = p->isDistinct;
+  pEList = p->pEList;
+  if( pEList==0 ) goto select_end;
+
+  /* 
+  ** Do not even attempt to generate any code if we have already seen
+  ** errors before this routine starts.
+  */
+  if( pParse->nErr>0 ) goto select_end;
+
+  /* If writing to memory or generating a set
+  ** only a single column may be output.
+  */
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
+    goto select_end;
+  }
+#endif
+
+  /* ORDER BY is ignored for some destinations.
+  */
+  if( IgnorableOrderby(pDest) ){
+    pOrderBy = 0;
+  }
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto select_end;
+
+  /* Generate code for all sub-queries in the FROM clause
+  */
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+  for(i=0; i<pTabList->nSrc; i++){
+    const char *zSavedAuthContext = 0;
+    int needRestoreContext;
+    struct SrcList_item *pItem = &pTabList->a[i];
+    SelectDest dest;
+
+    if( pItem->pSelect==0 || pItem->isPopulated ) continue;
+    if( pItem->zName!=0 ){
+      zSavedAuthContext = pParse->zAuthContext;
+      pParse->zAuthContext = pItem->zName;
+      needRestoreContext = 1;
+    }else{
+      needRestoreContext = 0;
+    }
+    /* Increment Parse.nHeight by the height of the largest expression
+    ** tree refered to by this, the parent select. The child select
+    ** may contain expression trees of at most
+    ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
+    ** more conservative than necessary, but much easier than enforcing
+    ** an exact limit.
+    */
+    pParse->nHeight += sqlite3SelectExprHeight(p);
+    sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
+    sqlite3Select(pParse, pItem->pSelect, &dest, p, i, &isAgg, 0);
+    if( db->mallocFailed ){
+      goto select_end;
+    }
+    pParse->nHeight -= sqlite3SelectExprHeight(p);
+    if( needRestoreContext ){
+      pParse->zAuthContext = zSavedAuthContext;
+    }
+    pTabList = p->pSrc;
+    pWhere = p->pWhere;
+    if( !IgnorableOrderby(pDest) ){
+      pOrderBy = p->pOrderBy;
+    }
+    pGroupBy = p->pGroupBy;
+    pHaving = p->pHaving;
+    isDistinct = p->isDistinct;
+  }
+#endif
+
+  /* Check to see if this is a subquery that can be "flattened" into its parent.
+  ** If flattening is a possiblity, do so and return immediately.  
+  */
+#ifndef SQLITE_OMIT_VIEW
+  if( pParent && pParentAgg &&
+      flattenSubquery(db, pParent, parentTab, *pParentAgg, isAgg) ){
+    if( isAgg ) *pParentAgg = 1;
+    goto select_end;
+  }
+#endif
+
+  /* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
+  ** GROUP BY may use an index, DISTINCT never does.
+  */
+  if( p->isDistinct && !p->isAgg && !p->pGroupBy ){
+    p->pGroupBy = sqlite3ExprListDup(db, p->pEList);
+    pGroupBy = p->pGroupBy;
+    p->isDistinct = 0;
+    isDistinct = 0;
+  }
+
+  /* If there is an ORDER BY clause, then this sorting
+  ** index might end up being unused if the data can be 
+  ** extracted in pre-sorted order.  If that is the case, then the
+  ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
+  ** we figure out that the sorting index is not needed.  The addrSortIndex
+  ** variable is used to facilitate that change.
+  */
+  if( pOrderBy ){
+    KeyInfo *pKeyInfo;
+    pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
+    pOrderBy->iECursor = pParse->nTab++;
+    p->addrOpenEphm[2] = addrSortIndex =
+      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+                           pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
+                           (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+  }else{
+    addrSortIndex = -1;
+  }
+
+  /* If the output is destined for a temporary table, open that table.
+  */
+  if( pDest->eDest==SRT_EphemTab ){
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
+  }
+
+  /* Set the limiter.
+  */
+  iEnd = sqlite3VdbeMakeLabel(v);
+  computeLimitRegisters(pParse, p, iEnd);
+
+  /* Open a virtual index to use for the distinct set.
+  */
+  if( isDistinct ){
+    KeyInfo *pKeyInfo;
+    assert( isAgg || pGroupBy );
+    distinct = pParse->nTab++;
+    pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
+    sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
+                        (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+  }else{
+    distinct = -1;
+  }
+
+  /* Aggregate and non-aggregate queries are handled differently */
+  if( !isAgg && pGroupBy==0 ){
+    /* This case is for non-aggregate queries
+    ** Begin the database scan
+    */
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, 0);
+    if( pWInfo==0 ) goto select_end;
+
+    /* If sorting index that was created by a prior OP_OpenEphemeral 
+    ** instruction ended up not being needed, then change the OP_OpenEphemeral
+    ** into an OP_Noop.
+    */
+    if( addrSortIndex>=0 && pOrderBy==0 ){
+      sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
+      p->addrOpenEphm[2] = -1;
+    }
+
+    /* Use the standard inner loop
+    */
+    assert(!isDistinct);
+    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
+                    pWInfo->iContinue, pWInfo->iBreak, aff);
+
+    /* End the database scan loop.
+    */
+    sqlite3WhereEnd(pWInfo);
+  }else{
+    /* This is the processing for aggregate queries */
+    NameContext sNC;    /* Name context for processing aggregate information */
+    int iAMem;          /* First Mem address for storing current GROUP BY */
+    int iBMem;          /* First Mem address for previous GROUP BY */
+    int iUseFlag;       /* Mem address holding flag indicating that at least
+                        ** one row of the input to the aggregator has been
+                        ** processed */
+    int iAbortFlag;     /* Mem address which causes query abort if positive */
+    int groupBySort;    /* Rows come from source in GROUP BY order */
+
+
+    /* The following variables hold addresses or labels for parts of the
+    ** virtual machine program we are putting together */
+    int addrOutputRow;      /* Start of subroutine that outputs a result row */
+    int addrSetAbort;       /* Set the abort flag and return */
+    int addrInitializeLoop; /* Start of code that initializes the input loop */
+    int addrTopOfLoop;      /* Top of the input loop */
+    int addrGroupByChange;  /* Code that runs when any GROUP BY term changes */
+    int addrProcessRow;     /* Code to process a single input row */
+    int addrEnd;            /* End of all processing */
+    int addrSortingIdx;     /* The OP_OpenEphemeral for the sorting index */
+    int addrReset;          /* Subroutine for resetting the accumulator */
+
+    addrEnd = sqlite3VdbeMakeLabel(v);
+
+    /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
+    ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
+    ** SELECT statement.
+    */
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    sNC.pSrcList = pTabList;
+    sNC.pAggInfo = &sAggInfo;
+    sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
+    sAggInfo.pGroupBy = pGroupBy;
+    sqlite3ExprAnalyzeAggList(&sNC, pEList);
+    sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
+    if( pHaving ){
+      sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
+    }
+    sAggInfo.nAccumulator = sAggInfo.nColumn;
+    for(i=0; i<sAggInfo.nFunc; i++){
+      sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList);
+    }
+    if( db->mallocFailed ) goto select_end;
+
+    /* Processing for aggregates with GROUP BY is very different and
+    ** much more complex than aggregates without a GROUP BY.
+    */
+    if( pGroupBy ){
+      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */
+
+      /* Create labels that we will be needing
+      */
+     
+      addrInitializeLoop = sqlite3VdbeMakeLabel(v);
+      addrGroupByChange = sqlite3VdbeMakeLabel(v);
+      addrProcessRow = sqlite3VdbeMakeLabel(v);
+
+      /* If there is a GROUP BY clause we might need a sorting index to
+      ** implement it.  Allocate that sorting index now.  If it turns out
+      ** that we do not need it after all, the OpenEphemeral instruction
+      ** will be converted into a Noop.  
+      */
+      sAggInfo.sortingIdx = pParse->nTab++;
+      pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
+      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, 
+          sAggInfo.sortingIdx, sAggInfo.nSortingColumn, 
+          0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+
+      /* Initialize memory locations used by GROUP BY aggregate processing
+      */
+      iUseFlag = ++pParse->nMem;
+      iAbortFlag = ++pParse->nMem;
+      iAMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      iBMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
+      VdbeComment((v, "clear abort flag"));
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
+      VdbeComment((v, "indicate accumulator empty"));
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrInitializeLoop);
+
+      /* Generate a subroutine that outputs a single row of the result
+      ** set.  This subroutine first looks at the iUseFlag.  If iUseFlag
+      ** is less than or equal to zero, the subroutine is a no-op.  If
+      ** the processing calls for the query to abort, this subroutine
+      ** increments the iAbortFlag memory location before returning in
+      ** order to signal the caller to abort.
+      */
+      addrSetAbort = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
+      VdbeComment((v, "set abort flag"));
+      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+      addrOutputRow = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
+      VdbeComment((v, "Groupby result generator entry point"));
+      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+      finalizeAggFunctions(pParse, &sAggInfo);
+      if( pHaving ){
+        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
+      }
+      selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
+                      distinct, pDest,
+                      addrOutputRow+1, addrSetAbort, aff);
+      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+      VdbeComment((v, "end groupby result generator"));
+
+      /* Generate a subroutine that will reset the group-by accumulator
+      */
+      addrReset = sqlite3VdbeCurrentAddr(v);
+      resetAccumulator(pParse, &sAggInfo);
+      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
+
+      /* Begin a loop that will extract all source rows in GROUP BY order.
+      ** This might involve two separate loops with an OP_Sort in between, or
+      ** it might be a single loop that uses an index to extract information
+      ** in the right order to begin with.
+      */
+      sqlite3VdbeResolveLabel(v, addrInitializeLoop);
+      sqlite3VdbeAddOp2(v, OP_Gosub, 0, addrReset);
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0);
+      if( pWInfo==0 ) goto select_end;
+      if( pGroupBy==0 ){
+        /* The optimizer is able to deliver rows in group by order so
+        ** we do not have to sort.  The OP_OpenEphemeral table will be
+        ** cancelled later because we still need to use the pKeyInfo
+        */
+        pGroupBy = p->pGroupBy;
+        groupBySort = 0;
+      }else{
+        /* Rows are coming out in undetermined order.  We have to push
+        ** each row into a sorting index, terminate the first loop,
+        ** then loop over the sorting index in order to get the output
+        ** in sorted order
+        */
+        int regBase;
+        int regRecord;
+        int nCol;
+        int nGroupBy;
+
+        groupBySort = 1;
+        nGroupBy = pGroupBy->nExpr;
+        nCol = nGroupBy + 1;
+        j = nGroupBy+1;
+        for(i=0; i<sAggInfo.nColumn; i++){
+          if( sAggInfo.aCol[i].iSorterColumn>=j ){
+            nCol++;
+            j++;
+          }
+        }
+        regBase = sqlite3GetTempRange(pParse, nCol);
+        sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
+        sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
+        j = nGroupBy+1;
+        for(i=0; i<sAggInfo.nColumn; i++){
+          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
+          if( pCol->iSorterColumn>=j ){
+            int r1 = j + regBase;
+            int r2 = sqlite3ExprCodeGetColumn(pParse, 
+                               pCol->pTab, pCol->iColumn, pCol->iTable, r1, 0);
+            if( r1!=r2 ){
+              sqlite3VdbeAddOp2(v, OP_SCopy, r2, r1);
+            }
+            j++;
+          }
+        }
+        regRecord = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, sAggInfo.sortingIdx, regRecord);
+        sqlite3ReleaseTempReg(pParse, regRecord);
+        sqlite3ReleaseTempRange(pParse, regBase, nCol);
+        sqlite3WhereEnd(pWInfo);
+        sqlite3VdbeAddOp2(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
+        VdbeComment((v, "GROUP BY sort"));
+        sAggInfo.useSortingIdx = 1;
+      }
+
+      /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
+      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
+      ** Then compare the current GROUP BY terms against the GROUP BY terms
+      ** from the previous row currently stored in a0, a1, a2...
+      */
+      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
+      for(j=0; j<pGroupBy->nExpr; j++){
+        if( groupBySort ){
+          sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
+        }else{
+          sAggInfo.directMode = 1;
+          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
+        }
+      }
+      for(j=pGroupBy->nExpr-1; j>=0; j--){
+        if( j==0 ){
+          sqlite3VdbeAddOp3(v, OP_Eq, iAMem+j, addrProcessRow, iBMem+j);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_Ne, iAMem+j, addrGroupByChange, iBMem+j);
+        }
+        sqlite3VdbeChangeP4(v, -1, (void*)pKeyInfo->aColl[j], P4_COLLSEQ);
+        sqlite3VdbeChangeP5(v, SQLITE_NULLEQUAL);
+      }
+
+      /* Generate code that runs whenever the GROUP BY changes.
+      ** Change in the GROUP BY are detected by the previous code
+      ** block.  If there were no changes, this block is skipped.
+      **
+      ** This code copies current group by terms in b0,b1,b2,...
+      ** over to a0,a1,a2.  It then calls the output subroutine
+      ** and resets the aggregate accumulator registers in preparation
+      ** for the next GROUP BY batch.
+      */
+      sqlite3VdbeResolveLabel(v, addrGroupByChange);
+      for(j=0; j<pGroupBy->nExpr; j++){
+        sqlite3ExprCodeMove(pParse, iBMem+j, iAMem+j);
+      }
+      sqlite3VdbeAddOp2(v, OP_Gosub, 0, addrOutputRow);
+      VdbeComment((v, "output one row"));
+      sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
+      VdbeComment((v, "check abort flag"));
+      sqlite3VdbeAddOp2(v, OP_Gosub, 0, addrReset);
+      VdbeComment((v, "reset accumulator"));
+
+      /* Update the aggregate accumulators based on the content of
+      ** the current row
+      */
+      sqlite3VdbeResolveLabel(v, addrProcessRow);
+      updateAccumulator(pParse, &sAggInfo);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
+      VdbeComment((v, "indicate data in accumulator"));
+
+      /* End of the loop
+      */
+      if( groupBySort ){
+        sqlite3VdbeAddOp2(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
+      }else{
+        sqlite3WhereEnd(pWInfo);
+        sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
+      }
+
+      /* Output the final row of result
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, 0, addrOutputRow);
+      VdbeComment((v, "output final row"));
+      
+    } /* endif pGroupBy */
+    else {
+      ExprList *pMinMax = 0;
+      ExprList *pDel = 0;
+      u8 flag;
+
+      /* Check if the query is of one of the following forms:
+      **
+      **   SELECT min(x) FROM ...
+      **   SELECT max(x) FROM ...
+      **
+      ** If it is, then ask the code in where.c to attempt to sort results
+      ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause. 
+      ** If where.c is able to produce results sorted in this order, then
+      ** add vdbe code to break out of the processing loop after the 
+      ** first iteration (since the first iteration of the loop is 
+      ** guaranteed to operate on the row with the minimum or maximum 
+      ** value of x, the only row required).
+      **
+      ** A special flag must be passed to sqlite3WhereBegin() to slightly
+      ** modify behaviour as follows:
+      **
+      **   + If the query is a "SELECT min(x)", then the loop coded by
+      **     where.c should not iterate over any values with a NULL value
+      **     for x.
+      **
+      **   + The optimizer code in where.c (the thing that decides which
+      **     index or indices to use) should place a different priority on 
+      **     satisfying the 'ORDER BY' clause than it does in other cases.
+      **     Refer to code and comments in where.c for details.
+      */
+      flag = minMaxQuery(pParse, p);
+      if( flag ){
+        pDel = pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
+        if( pMinMax && !db->mallocFailed ){
+          pMinMax->a[0].sortOrder = ((flag==WHERE_ORDERBY_MIN)?0:1);
+          pMinMax->a[0].pExpr->op = TK_COLUMN;
+        }
+      }
+
+      /* This case runs if the aggregate has no GROUP BY clause.  The
+      ** processing is much simpler since there is only a single row
+      ** of output.
+      */
+      resetAccumulator(pParse, &sAggInfo);
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, flag);
+      if( pWInfo==0 ){
+        sqlite3ExprListDelete(pDel);
+        goto select_end;
+      }
+      updateAccumulator(pParse, &sAggInfo);
+      if( !pMinMax && flag ){
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
+        VdbeComment((v, "%s() by index", (flag==WHERE_ORDERBY_MIN?"min":"max")));
+      }
+      sqlite3WhereEnd(pWInfo);
+      finalizeAggFunctions(pParse, &sAggInfo);
+      pOrderBy = 0;
+      if( pHaving ){
+        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
+      }
+      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
+                      pDest, addrEnd, addrEnd, aff);
+
+      sqlite3ExprListDelete(pDel);
+    }
+    sqlite3VdbeResolveLabel(v, addrEnd);
+    
+  } /* endif aggregate query */
+
+  /* If there is an ORDER BY clause, then we need to sort the results
+  ** and send them to the callback one by one.
+  */
+  if( pOrderBy ){
+    generateSortTail(pParse, p, v, pEList->nExpr, pDest);
+  }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+  /* If this was a subquery, we have now converted the subquery into a
+  ** temporary table.  So set the SrcList_item.isPopulated flag to prevent
+  ** this subquery from being evaluated again and to force the use of
+  ** the temporary table.
+  */
+  if( pParent ){
+    assert( pParent->pSrc->nSrc>parentTab );
+    assert( pParent->pSrc->a[parentTab].pSelect==p );
+    pParent->pSrc->a[parentTab].isPopulated = 1;
+  }
+#endif
+
+  /* Jump here to skip this query
+  */
+  sqlite3VdbeResolveLabel(v, iEnd);
+
+  /* The SELECT was successfully coded.   Set the return code to 0
+  ** to indicate no errors.
+  */
+  rc = 0;
+
+  /* Control jumps to here if an error is encountered above, or upon
+  ** successful coding of the SELECT.
+  */
+select_end:
+
+  /* Identify column names if we will be using them in a callback.  This
+  ** step is skipped if the output is going to some other destination.
+  */
+  if( rc==SQLITE_OK && pDest->eDest==SRT_Callback ){
+    generateColumnNames(pParse, pTabList, pEList);
+  }
+
+  sqlite3_free(sAggInfo.aCol);
+  sqlite3_free(sAggInfo.aFunc);
+  return rc;
+}
+
+#if defined(SQLITE_DEBUG)
+/*
+*******************************************************************************
+** The following code is used for testing and debugging only.  The code
+** that follows does not appear in normal builds.
+**
+** These routines are used to print out the content of all or part of a 
+** parse structures such as Select or Expr.  Such printouts are useful
+** for helping to understand what is happening inside the code generator
+** during the execution of complex SELECT statements.
+**
+** These routine are not called anywhere from within the normal
+** code base.  Then are intended to be called from within the debugger
+** or from temporary "printf" statements inserted for debugging.
+*/
+SQLITE_PRIVATE void sqlite3PrintExpr(Expr *p){
+  if( p->token.z && p->token.n>0 ){
+    sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
+  }else{
+    sqlite3DebugPrintf("(%d", p->op);
+  }
+  if( p->pLeft ){
+    sqlite3DebugPrintf(" ");
+    sqlite3PrintExpr(p->pLeft);
+  }
+  if( p->pRight ){
+    sqlite3DebugPrintf(" ");
+    sqlite3PrintExpr(p->pRight);
+  }
+  sqlite3DebugPrintf(")");
+}
+SQLITE_PRIVATE void sqlite3PrintExprList(ExprList *pList){
+  int i;
+  for(i=0; i<pList->nExpr; i++){
+    sqlite3PrintExpr(pList->a[i].pExpr);
+    if( i<pList->nExpr-1 ){
+      sqlite3DebugPrintf(", ");
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3PrintSelect(Select *p, int indent){
+  sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
+  sqlite3PrintExprList(p->pEList);
+  sqlite3DebugPrintf("\n");
+  if( p->pSrc ){
+    char *zPrefix;
+    int i;
+    zPrefix = "FROM";
+    for(i=0; i<p->pSrc->nSrc; i++){
+      struct SrcList_item *pItem = &p->pSrc->a[i];
+      sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
+      zPrefix = "";
+      if( pItem->pSelect ){
+        sqlite3DebugPrintf("(\n");
+        sqlite3PrintSelect(pItem->pSelect, indent+10);
+        sqlite3DebugPrintf("%*s)", indent+8, "");
+      }else if( pItem->zName ){
+        sqlite3DebugPrintf("%s", pItem->zName);
+      }
+      if( pItem->pTab ){
+        sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
+      }
+      if( pItem->zAlias ){
+        sqlite3DebugPrintf(" AS %s", pItem->zAlias);
+      }
+      if( i<p->pSrc->nSrc-1 ){
+        sqlite3DebugPrintf(",");
+      }
+      sqlite3DebugPrintf("\n");
+    }
+  }
+  if( p->pWhere ){
+    sqlite3DebugPrintf("%*s WHERE ", indent, "");
+    sqlite3PrintExpr(p->pWhere);
+    sqlite3DebugPrintf("\n");
+  }
+  if( p->pGroupBy ){
+    sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
+    sqlite3PrintExprList(p->pGroupBy);
+    sqlite3DebugPrintf("\n");
+  }
+  if( p->pHaving ){
+    sqlite3DebugPrintf("%*s HAVING ", indent, "");
+    sqlite3PrintExpr(p->pHaving);
+    sqlite3DebugPrintf("\n");
+  }
+  if( p->pOrderBy ){
+    sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
+    sqlite3PrintExprList(p->pOrderBy);
+    sqlite3DebugPrintf("\n");
+  }
+}
+/* End of the structure debug printing code
+*****************************************************************************/
+#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
+
+/************** End of select.c **********************************************/
+/************** Begin file table.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the sqlite3_get_table() and sqlite3_free_table()
+** interface routines.  These are just wrappers around the main
+** interface routine of sqlite3_exec().
+**
+** These routines are in a separate files so that they will not be linked
+** if they are not used.
+*/
+
+#ifndef SQLITE_OMIT_GET_TABLE
+
+/*
+** This structure is used to pass data from sqlite3_get_table() through
+** to the callback function is uses to build the result.
+*/
+typedef struct TabResult {
+  char **azResult;
+  char *zErrMsg;
+  int nResult;
+  int nAlloc;
+  int nRow;
+  int nColumn;
+  int nData;
+  int rc;
+} TabResult;
+
+/*
+** This routine is called once for each row in the result table.  Its job
+** is to fill in the TabResult structure appropriately, allocating new
+** memory as necessary.
+*/
+static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
+  TabResult *p = (TabResult*)pArg;
+  int need;
+  int i;
+  char *z;
+
+  /* Make sure there is enough space in p->azResult to hold everything
+  ** we need to remember from this invocation of the callback.
+  */
+  if( p->nRow==0 && argv!=0 ){
+    need = nCol*2;
+  }else{
+    need = nCol;
+  }
+  if( p->nData + need >= p->nAlloc ){
+    char **azNew;
+    p->nAlloc = p->nAlloc*2 + need + 1;
+    azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc );
+    if( azNew==0 ) goto malloc_failed;
+    p->azResult = azNew;
+  }
+
+  /* If this is the first row, then generate an extra row containing
+  ** the names of all columns.
+  */
+  if( p->nRow==0 ){
+    p->nColumn = nCol;
+    for(i=0; i<nCol; i++){
+      z = sqlite3_mprintf("%s", colv[i]);
+      if( z==0 ) goto malloc_failed;
+      p->azResult[p->nData++] = z;
+    }
+  }else if( p->nColumn!=nCol ){
+    sqlite3_free(p->zErrMsg);
+    p->zErrMsg = sqlite3_mprintf(
+       "sqlite3_get_table() called with two or more incompatible queries"
+    );
+    p->rc = SQLITE_ERROR;
+    return 1;
+  }
+
+  /* Copy over the row data
+  */
+  if( argv!=0 ){
+    for(i=0; i<nCol; i++){
+      if( argv[i]==0 ){
+        z = 0;
+      }else{
+        int n = strlen(argv[i])+1;
+        z = sqlite3_malloc( n );
+        if( z==0 ) goto malloc_failed;
+        memcpy(z, argv[i], n);
+      }
+      p->azResult[p->nData++] = z;
+    }
+    p->nRow++;
+  }
+  return 0;
+
+malloc_failed:
+  p->rc = SQLITE_NOMEM;
+  return 1;
+}
+
+/*
+** Query the database.  But instead of invoking a callback for each row,
+** malloc() for space to hold the result and return the entire results
+** at the conclusion of the call.
+**
+** The result that is written to ***pazResult is held in memory obtained
+** from malloc().  But the caller cannot free this memory directly.  
+** Instead, the entire table should be passed to sqlite3_free_table() when
+** the calling procedure is finished using it.
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  char ***pazResult,          /* Write the result table here */
+  int *pnRow,                 /* Write the number of rows in the result here */
+  int *pnColumn,              /* Write the number of columns of result here */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc;
+  TabResult res;
+
+  *pazResult = 0;
+  if( pnColumn ) *pnColumn = 0;
+  if( pnRow ) *pnRow = 0;
+  res.zErrMsg = 0;
+  res.nResult = 0;
+  res.nRow = 0;
+  res.nColumn = 0;
+  res.nData = 1;
+  res.nAlloc = 20;
+  res.rc = SQLITE_OK;
+  res.azResult = sqlite3_malloc(sizeof(char*)*res.nAlloc );
+  if( res.azResult==0 ){
+     db->errCode = SQLITE_NOMEM;
+     return SQLITE_NOMEM;
+  }
+  res.azResult[0] = 0;
+  rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg);
+  assert( sizeof(res.azResult[0])>= sizeof(res.nData) );
+  res.azResult[0] = (char*)res.nData;
+  if( (rc&0xff)==SQLITE_ABORT ){
+    sqlite3_free_table(&res.azResult[1]);
+    if( res.zErrMsg ){
+      if( pzErrMsg ){
+        sqlite3_free(*pzErrMsg);
+        *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg);
+      }
+      sqlite3_free(res.zErrMsg);
+    }
+    db->errCode = res.rc;  /* Assume 32-bit assignment is atomic */
+    return res.rc;
+  }
+  sqlite3_free(res.zErrMsg);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free_table(&res.azResult[1]);
+    return rc;
+  }
+  if( res.nAlloc>res.nData ){
+    char **azNew;
+    azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) );
+    if( azNew==0 ){
+      sqlite3_free_table(&res.azResult[1]);
+      db->errCode = SQLITE_NOMEM;
+      return SQLITE_NOMEM;
+    }
+    res.nAlloc = res.nData+1;
+    res.azResult = azNew;
+  }
+  *pazResult = &res.azResult[1];
+  if( pnColumn ) *pnColumn = res.nColumn;
+  if( pnRow ) *pnRow = res.nRow;
+  return rc;
+}
+
+/*
+** This routine frees the space the sqlite3_get_table() malloced.
+*/
+SQLITE_API void sqlite3_free_table(
+  char **azResult            /* Result returned from from sqlite3_get_table() */
+){
+  if( azResult ){
+    int i, n;
+    azResult--;
+    assert( azResult!=0 );
+    n = (int)azResult[0];
+    for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); }
+    sqlite3_free(azResult);
+  }
+}
+
+#endif /* SQLITE_OMIT_GET_TABLE */
+
+/************** End of table.c ***********************************************/
+/************** Begin file trigger.c *****************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*
+*/
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Delete a linked list of TriggerStep structures.
+*/
+SQLITE_PRIVATE void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){
+  while( pTriggerStep ){
+    TriggerStep * pTmp = pTriggerStep;
+    pTriggerStep = pTriggerStep->pNext;
+
+    if( pTmp->target.dyn ) sqlite3_free((char*)pTmp->target.z);
+    sqlite3ExprDelete(pTmp->pWhere);
+    sqlite3ExprListDelete(pTmp->pExprList);
+    sqlite3SelectDelete(pTmp->pSelect);
+    sqlite3IdListDelete(pTmp->pIdList);
+
+    sqlite3_free(pTmp);
+  }
+}
+
+/*
+** This is called by the parser when it sees a CREATE TRIGGER statement
+** up to the point of the BEGIN before the trigger actions.  A Trigger
+** structure is generated based on the information available and stored
+** in pParse->pNewTrigger.  After the trigger actions have been parsed, the
+** sqlite3FinishTrigger() function is called to complete the trigger
+** construction process.
+*/
+SQLITE_PRIVATE void sqlite3BeginTrigger(
+  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */
+  Token *pName1,      /* The name of the trigger */
+  Token *pName2,      /* The name of the trigger */
+  int tr_tm,          /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
+  int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
+  IdList *pColumns,   /* column list if this is an UPDATE OF trigger */
+  SrcList *pTableName,/* The name of the table/view the trigger applies to */
+  Expr *pWhen,        /* WHEN clause */
+  int isTemp,         /* True if the TEMPORARY keyword is present */
+  int noErr           /* Suppress errors if the trigger already exists */
+){
+  Trigger *pTrigger = 0;
+  Table *pTab;
+  char *zName = 0;        /* Name of the trigger */
+  sqlite3 *db = pParse->db;
+  int iDb;                /* The database to store the trigger in */
+  Token *pName;           /* The unqualified db name */
+  DbFixer sFix;
+  int iTabDb;
+
+  assert( pName1!=0 );   /* pName1->z might be NULL, but not pName1 itself */
+  assert( pName2!=0 );
+  if( isTemp ){
+    /* If TEMP was specified, then the trigger name may not be qualified. */
+    if( pName2->n>0 ){
+      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
+      goto trigger_cleanup;
+    }
+    iDb = 1;
+    pName = pName1;
+  }else{
+    /* Figure out the db that the the trigger will be created in */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ){
+      goto trigger_cleanup;
+    }
+  }
+
+  /* If the trigger name was unqualified, and the table is a temp table,
+  ** then set iDb to 1 to create the trigger in the temporary database.
+  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
+  ** exist, the error is caught by the block below.
+  */
+  if( !pTableName || db->mallocFailed ){
+    goto trigger_cleanup;
+  }
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+    iDb = 1;
+  }
+
+  /* Ensure the table name matches database name and that the table exists */
+  if( db->mallocFailed ) goto trigger_cleanup;
+  assert( pTableName->nSrc==1 );
+  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 
+      sqlite3FixSrcList(&sFix, pTableName) ){
+    goto trigger_cleanup;
+  }
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( !pTab ){
+    /* The table does not exist. */
+    goto trigger_cleanup;
+  }
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
+    goto trigger_cleanup;
+  }
+
+  /* Check that the trigger name is not reserved and that no trigger of the
+  ** specified name exists */
+  zName = sqlite3NameFromToken(db, pName);
+  if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
+    goto trigger_cleanup;
+  }
+  if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
+    if( !noErr ){
+      sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
+    }
+    goto trigger_cleanup;
+  }
+
+  /* Do not create a trigger on a system table */
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+    sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
+    pParse->nErr++;
+    goto trigger_cleanup;
+  }
+
+  /* INSTEAD of triggers are only for views and views only support INSTEAD
+  ** of triggers.
+  */
+  if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S", 
+        (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
+    goto trigger_cleanup;
+  }
+  if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
+        " trigger on table: %S", pTableName, 0);
+    goto trigger_cleanup;
+  }
+  iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code = SQLITE_CREATE_TRIGGER;
+    const char *zDb = db->aDb[iTabDb].zName;
+    const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
+    if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
+      goto trigger_cleanup;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
+      goto trigger_cleanup;
+    }
+  }
+#endif
+
+  /* INSTEAD OF triggers can only appear on views and BEFORE triggers
+  ** cannot appear on views.  So we might as well translate every
+  ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code
+  ** elsewhere.
+  */
+  if (tr_tm == TK_INSTEAD){
+    tr_tm = TK_BEFORE;
+  }
+
+  /* Build the Trigger object */
+  pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
+  if( pTrigger==0 ) goto trigger_cleanup;
+  pTrigger->name = zName;
+  zName = 0;
+  pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
+  pTrigger->pSchema = db->aDb[iDb].pSchema;
+  pTrigger->pTabSchema = pTab->pSchema;
+  pTrigger->op = op;
+  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
+  pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
+  pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
+  sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
+  assert( pParse->pNewTrigger==0 );
+  pParse->pNewTrigger = pTrigger;
+
+trigger_cleanup:
+  sqlite3_free(zName);
+  sqlite3SrcListDelete(pTableName);
+  sqlite3IdListDelete(pColumns);
+  sqlite3ExprDelete(pWhen);
+  if( !pParse->pNewTrigger ){
+    sqlite3DeleteTrigger(pTrigger);
+  }else{
+    assert( pParse->pNewTrigger==pTrigger );
+  }
+}
+
+/*
+** This routine is called after all of the trigger actions have been parsed
+** in order to complete the process of building the trigger.
+*/
+SQLITE_PRIVATE void sqlite3FinishTrigger(
+  Parse *pParse,          /* Parser context */
+  TriggerStep *pStepList, /* The triggered program */
+  Token *pAll             /* Token that describes the complete CREATE TRIGGER */
+){
+  Trigger *pTrig = 0;     /* The trigger whose construction is finishing up */
+  sqlite3 *db = pParse->db;  /* The database */
+  DbFixer sFix;
+  int iDb;                   /* Database containing the trigger */
+
+  pTrig = pParse->pNewTrigger;
+  pParse->pNewTrigger = 0;
+  if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
+  pTrig->step_list = pStepList;
+  while( pStepList ){
+    pStepList->pTrig = pTrig;
+    pStepList = pStepList->pNext;
+  }
+  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken) 
+          && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
+    goto triggerfinish_cleanup;
+  }
+
+  /* if we are not initializing, and this trigger is not on a TEMP table, 
+  ** build the sqlite_master entry
+  */
+  if( !db->init.busy ){
+    Vdbe *v;
+    char *z;
+
+    /* Make an entry in the sqlite_master table */
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) goto triggerfinish_cleanup;
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
+    sqlite3NestedParse(pParse,
+       "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
+       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrig->name,
+       pTrig->table, z);
+    sqlite3_free(z);
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf(
+        db, "type='trigger' AND name='%q'", pTrig->name), P4_DYNAMIC
+    );
+  }
+
+  if( db->init.busy ){
+    int n;
+    Table *pTab;
+    Trigger *pDel;
+    pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
+                     pTrig->name, strlen(pTrig->name), pTrig);
+    if( pDel ){
+      assert( pDel==pTrig );
+      db->mallocFailed = 1;
+      goto triggerfinish_cleanup;
+    }
+    n = strlen(pTrig->table) + 1;
+    pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
+    assert( pTab!=0 );
+    pTrig->pNext = pTab->pTrigger;
+    pTab->pTrigger = pTrig;
+    pTrig = 0;
+  }
+
+triggerfinish_cleanup:
+  sqlite3DeleteTrigger(pTrig);
+  assert( !pParse->pNewTrigger );
+  sqlite3DeleteTriggerStep(pStepList);
+}
+
+/*
+** Make a copy of all components of the given trigger step.  This has
+** the effect of copying all Expr.token.z values into memory obtained
+** from sqlite3_malloc().  As initially created, the Expr.token.z values
+** all point to the input string that was fed to the parser.  But that
+** string is ephemeral - it will go away as soon as the sqlite3_exec()
+** call that started the parser exits.  This routine makes a persistent
+** copy of all the Expr.token.z strings so that the TriggerStep structure
+** will be valid even after the sqlite3_exec() call returns.
+*/
+static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
+  if( p->target.z ){
+    p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
+    p->target.dyn = 1;
+  }
+  if( p->pSelect ){
+    Select *pNew = sqlite3SelectDup(db, p->pSelect);
+    sqlite3SelectDelete(p->pSelect);
+    p->pSelect = pNew;
+  }
+  if( p->pWhere ){
+    Expr *pNew = sqlite3ExprDup(db, p->pWhere);
+    sqlite3ExprDelete(p->pWhere);
+    p->pWhere = pNew;
+  }
+  if( p->pExprList ){
+    ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
+    sqlite3ExprListDelete(p->pExprList);
+    p->pExprList = pNew;
+  }
+  if( p->pIdList ){
+    IdList *pNew = sqlite3IdListDup(db, p->pIdList);
+    sqlite3IdListDelete(p->pIdList);
+    p->pIdList = pNew;
+  }
+}
+
+/*
+** Turn a SELECT statement (that the pSelect parameter points to) into
+** a trigger step.  Return a pointer to a TriggerStep structure.
+**
+** The parser calls this routine when it finds a SELECT statement in
+** body of a TRIGGER.  
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
+  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep==0 ) {
+    sqlite3SelectDelete(pSelect);
+    return 0;
+  }
+
+  pTriggerStep->op = TK_SELECT;
+  pTriggerStep->pSelect = pSelect;
+  pTriggerStep->orconf = OE_Default;
+  sqlitePersistTriggerStep(db, pTriggerStep);
+
+  return pTriggerStep;
+}
+
+/*
+** Build a trigger step out of an INSERT statement.  Return a pointer
+** to the new trigger step.
+**
+** The parser calls this routine when it sees an INSERT inside the
+** body of a trigger.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerInsertStep(
+  sqlite3 *db,        /* The database connection */
+  Token *pTableName,  /* Name of the table into which we insert */
+  IdList *pColumn,    /* List of columns in pTableName to insert into */
+  ExprList *pEList,   /* The VALUE clause: a list of values to be inserted */
+  Select *pSelect,    /* A SELECT statement that supplies values */
+  int orconf          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
+){
+  TriggerStep *pTriggerStep;
+
+  assert(pEList == 0 || pSelect == 0);
+  assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
+
+  pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep ){
+    pTriggerStep->op = TK_INSERT;
+    pTriggerStep->pSelect = pSelect;
+    pTriggerStep->target  = *pTableName;
+    pTriggerStep->pIdList = pColumn;
+    pTriggerStep->pExprList = pEList;
+    pTriggerStep->orconf = orconf;
+    sqlitePersistTriggerStep(db, pTriggerStep);
+  }else{
+    sqlite3IdListDelete(pColumn);
+    sqlite3ExprListDelete(pEList);
+    sqlite3SelectDelete(pSelect);
+  }
+
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements an UPDATE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees an UPDATE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerUpdateStep(
+  sqlite3 *db,         /* The database connection */
+  Token *pTableName,   /* Name of the table to be updated */
+  ExprList *pEList,    /* The SET clause: list of column and new values */
+  Expr *pWhere,        /* The WHERE clause */
+  int orconf           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
+){
+  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep==0 ){
+     sqlite3ExprListDelete(pEList);
+     sqlite3ExprDelete(pWhere);
+     return 0;
+  }
+
+  pTriggerStep->op = TK_UPDATE;
+  pTriggerStep->target  = *pTableName;
+  pTriggerStep->pExprList = pEList;
+  pTriggerStep->pWhere = pWhere;
+  pTriggerStep->orconf = orconf;
+  sqlitePersistTriggerStep(db, pTriggerStep);
+
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements a DELETE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees a DELETE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerDeleteStep(
+  sqlite3 *db,            /* Database connection */
+  Token *pTableName,      /* The table from which rows are deleted */
+  Expr *pWhere            /* The WHERE clause */
+){
+  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep==0 ){
+    sqlite3ExprDelete(pWhere);
+    return 0;
+  }
+
+  pTriggerStep->op = TK_DELETE;
+  pTriggerStep->target  = *pTableName;
+  pTriggerStep->pWhere = pWhere;
+  pTriggerStep->orconf = OE_Default;
+  sqlitePersistTriggerStep(db, pTriggerStep);
+
+  return pTriggerStep;
+}
+
+/* 
+** Recursively delete a Trigger structure
+*/
+SQLITE_PRIVATE void sqlite3DeleteTrigger(Trigger *pTrigger){
+  if( pTrigger==0 ) return;
+  sqlite3DeleteTriggerStep(pTrigger->step_list);
+  sqlite3_free(pTrigger->name);
+  sqlite3_free(pTrigger->table);
+  sqlite3ExprDelete(pTrigger->pWhen);
+  sqlite3IdListDelete(pTrigger->pColumns);
+  if( pTrigger->nameToken.dyn ) sqlite3_free((char*)pTrigger->nameToken.z);
+  sqlite3_free(pTrigger);
+}
+
+/*
+** This function is called to drop a trigger from the database schema. 
+**
+** This may be called directly from the parser and therefore identifies
+** the trigger by name.  The sqlite3DropTriggerPtr() routine does the
+** same job as this routine except it takes a pointer to the trigger
+** instead of the trigger name.
+**/
+SQLITE_PRIVATE void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
+  Trigger *pTrigger = 0;
+  int i;
+  const char *zDb;
+  const char *zName;
+  int nName;
+  sqlite3 *db = pParse->db;
+
+  if( db->mallocFailed ) goto drop_trigger_cleanup;
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto drop_trigger_cleanup;
+  }
+
+  assert( pName->nSrc==1 );
+  zDb = pName->a[0].zDatabase;
+  zName = pName->a[0].zName;
+  nName = strlen(zName);
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
+    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
+    if( pTrigger ) break;
+  }
+  if( !pTrigger ){
+    if( !noErr ){
+      sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
+    }
+    goto drop_trigger_cleanup;
+  }
+  sqlite3DropTriggerPtr(pParse, pTrigger);
+
+drop_trigger_cleanup:
+  sqlite3SrcListDelete(pName);
+}
+
+/*
+** Return a pointer to the Table structure for the table that a trigger
+** is set on.
+*/
+static Table *tableOfTrigger(Trigger *pTrigger){
+  int n = strlen(pTrigger->table) + 1;
+  return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
+}
+
+
+/*
+** Drop a trigger given a pointer to that trigger. 
+*/
+SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
+  Table   *pTable;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  pTable = tableOfTrigger(pTrigger);
+  assert( pTable );
+  assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code = SQLITE_DROP_TRIGGER;
+    const char *zDb = db->aDb[iDb].zName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
+      sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      return;
+    }
+  }
+#endif
+
+  /* Generate code to destroy the database record of the trigger.
+  */
+  assert( pTable!=0 );
+  if( (v = sqlite3GetVdbe(pParse))!=0 ){
+    int base;
+    static const VdbeOpList dropTrigger[] = {
+      { OP_Rewind,     0, ADDR(9),  0},
+      { OP_String8,    0, 1,        0}, /* 1 */
+      { OP_Column,     0, 1,        2},
+      { OP_Ne,         2, ADDR(8),  1},
+      { OP_String8,    0, 1,        0}, /* 4: "trigger" */
+      { OP_Column,     0, 0,        2},
+      { OP_Ne,         2, ADDR(8),  1},
+      { OP_Delete,     0, 0,        0},
+      { OP_Next,       0, ADDR(1),  0}, /* 8 */
+    };
+
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3OpenMasterTable(pParse, iDb);
+    base = sqlite3VdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger);
+    sqlite3VdbeChangeP4(v, base+1, pTrigger->name, 0);
+    sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->name, 0);
+  }
+}
+
+/*
+** Remove a trigger from the hash tables of the sqlite* pointer.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
+  Trigger *pTrigger;
+  int nName = strlen(zName);
+  pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
+                               zName, nName, 0);
+  if( pTrigger ){
+    Table *pTable = tableOfTrigger(pTrigger);
+    assert( pTable!=0 );
+    if( pTable->pTrigger == pTrigger ){
+      pTable->pTrigger = pTrigger->pNext;
+    }else{
+      Trigger *cc = pTable->pTrigger;
+      while( cc ){ 
+        if( cc->pNext == pTrigger ){
+          cc->pNext = cc->pNext->pNext;
+          break;
+        }
+        cc = cc->pNext;
+      }
+      assert(cc);
+    }
+    sqlite3DeleteTrigger(pTrigger);
+    db->flags |= SQLITE_InternChanges;
+  }
+}
+
+/*
+** pEList is the SET clause of an UPDATE statement.  Each entry
+** in pEList is of the format <id>=<expr>.  If any of the entries
+** in pEList have an <id> which matches an identifier in pIdList,
+** then return TRUE.  If pIdList==NULL, then it is considered a
+** wildcard that matches anything.  Likewise if pEList==NULL then
+** it matches anything so always return true.  Return false only
+** if there is no match.
+*/
+static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
+  int e;
+  if( !pIdList || !pEList ) return 1;
+  for(e=0; e<pEList->nExpr; e++){
+    if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
+  }
+  return 0; 
+}
+
+/*
+** Return a bit vector to indicate what kind of triggers exist for operation
+** "op" on table pTab.  If pChanges is not NULL then it is a list of columns
+** that are being updated.  Triggers only match if the ON clause of the
+** trigger definition overlaps the set of columns being updated.
+**
+** The returned bit vector is some combination of TRIGGER_BEFORE and
+** TRIGGER_AFTER.
+*/
+SQLITE_PRIVATE int sqlite3TriggersExist(
+  Parse *pParse,          /* Used to check for recursive triggers */
+  Table *pTab,            /* The table the contains the triggers */
+  int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
+  ExprList *pChanges      /* Columns that change in an UPDATE statement */
+){
+  Trigger *pTrigger;
+  int mask = 0;
+
+  pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
+  while( pTrigger ){
+    if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
+      mask |= pTrigger->tr_tm;
+    }
+    pTrigger = pTrigger->pNext;
+  }
+  return mask;
+}
+
+/*
+** Convert the pStep->target token into a SrcList and return a pointer
+** to that SrcList.
+**
+** This routine adds a specific database name, if needed, to the target when
+** forming the SrcList.  This prevents a trigger in one database from
+** referring to a target in another database.  An exception is when the
+** trigger is in TEMP in which case it can refer to any other database it
+** wants.
+*/
+static SrcList *targetSrcList(
+  Parse *pParse,       /* The parsing context */
+  TriggerStep *pStep   /* The trigger containing the target token */
+){
+  Token sDb;           /* Dummy database name token */
+  int iDb;             /* Index of the database to use */
+  SrcList *pSrc;       /* SrcList to be returned */
+
+  iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
+  if( iDb==0 || iDb>=2 ){
+    assert( iDb<pParse->db->nDb );
+    sDb.z = (u8*)pParse->db->aDb[iDb].zName;
+    sDb.n = strlen((char*)sDb.z);
+    pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
+  } else {
+    pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
+  }
+  return pSrc;
+}
+
+/*
+** Generate VDBE code for zero or more statements inside the body of a
+** trigger.  
+*/
+static int codeTriggerProgram(
+  Parse *pParse,            /* The parser context */
+  TriggerStep *pStepList,   /* List of statements inside the trigger body */
+  int orconfin              /* Conflict algorithm. (OE_Abort, etc) */  
+){
+  TriggerStep * pTriggerStep = pStepList;
+  int orconf;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+
+  assert( pTriggerStep!=0 );
+  assert( v!=0 );
+  sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0);
+  VdbeComment((v, "begin trigger %s", pStepList->pTrig->name));
+  while( pTriggerStep ){
+    orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
+    pParse->trigStack->orconf = orconf;
+    switch( pTriggerStep->op ){
+      case TK_SELECT: {
+        Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
+        if( ss ){
+          SelectDest dest;
+
+          sqlite3SelectDestInit(&dest, SRT_Discard, 0);
+          sqlite3SelectResolve(pParse, ss, 0);
+          sqlite3Select(pParse, ss, &dest, 0, 0, 0, 0);
+          sqlite3SelectDelete(ss);
+        }
+        break;
+      }
+      case TK_UPDATE: {
+        SrcList *pSrc;
+        pSrc = targetSrcList(pParse, pTriggerStep);
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
+        sqlite3Update(pParse, pSrc,
+                sqlite3ExprListDup(db, pTriggerStep->pExprList), 
+                sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        break;
+      }
+      case TK_INSERT: {
+        SrcList *pSrc;
+        pSrc = targetSrcList(pParse, pTriggerStep);
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
+        sqlite3Insert(pParse, pSrc,
+          sqlite3ExprListDup(db, pTriggerStep->pExprList), 
+          sqlite3SelectDup(db, pTriggerStep->pSelect), 
+          sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        break;
+      }
+      case TK_DELETE: {
+        SrcList *pSrc;
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
+        pSrc = targetSrcList(pParse, pTriggerStep);
+        sqlite3DeleteFrom(pParse, pSrc, 
+                          sqlite3ExprDup(db, pTriggerStep->pWhere));
+        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        break;
+      }
+      default:
+        assert(0);
+    } 
+    pTriggerStep = pTriggerStep->pNext;
+  }
+  sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
+  VdbeComment((v, "end trigger %s", pStepList->pTrig->name));
+
+  return 0;
+}
+
+/*
+** This is called to code FOR EACH ROW triggers.
+**
+** When the code that this function generates is executed, the following 
+** must be true:
+**
+** 1. No cursors may be open in the main database.  (But newIdx and oldIdx
+**    can be indices of cursors in temporary tables.  See below.)
+**
+** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
+**    a temporary vdbe cursor (index newIdx) must be open and pointing at
+**    a row containing values to be substituted for new.* expressions in the
+**    trigger program(s).
+**
+** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
+**    a temporary vdbe cursor (index oldIdx) must be open and pointing at
+**    a row containing values to be substituted for old.* expressions in the
+**    trigger program(s).
+**
+** If they are not NULL, the piOldColMask and piNewColMask output variables
+** are set to values that describe the columns used by the trigger program
+** in the OLD.* and NEW.* tables respectively. If column N of the 
+** pseudo-table is read at least once, the corresponding bit of the output
+** mask is set. If a column with an index greater than 32 is read, the
+** output mask is set to the special value 0xffffffff.
+**
+*/
+SQLITE_PRIVATE int sqlite3CodeRowTrigger(
+  Parse *pParse,       /* Parse context */
+  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int newIdx,          /* The indice of the "new" row to access */
+  int oldIdx,          /* The indice of the "old" row to access */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump,      /* Instruction to jump to for RAISE(IGNORE) */
+  u32 *piOldColMask,   /* OUT: Mask of columns used from the OLD.* table */
+  u32 *piNewColMask    /* OUT: Mask of columns used from the NEW.* table */
+){
+  Trigger *p;
+  sqlite3 *db = pParse->db;
+  TriggerStack trigStackEntry;
+
+  trigStackEntry.oldColMask = 0;
+  trigStackEntry.newColMask = 0;
+
+  assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
+  assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
+
+  assert(newIdx != -1 || oldIdx != -1);
+
+  for(p=pTab->pTrigger; p; p=p->pNext){
+    int fire_this = 0;
+
+    /* Determine whether we should code this trigger */
+    if( 
+      p->op==op && 
+      p->tr_tm==tr_tm && 
+      (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
+      (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
+    ){
+      TriggerStack *pS;      /* Pointer to trigger-stack entry */
+      for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
+      if( !pS ){
+        fire_this = 1;
+      }
+#if 0    /* Give no warning for recursive triggers.  Just do not do them */
+      else{
+        sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
+            p->name);
+        return SQLITE_ERROR;
+      }
+#endif
+    }
+ 
+    if( fire_this ){
+      int endTrigger;
+      Expr * whenExpr;
+      AuthContext sContext;
+      NameContext sNC;
+
+#ifndef SQLITE_OMIT_TRACE
+      sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0,
+                        sqlite3MPrintf(db, "-- TRIGGER %s", p->name),
+                        P4_DYNAMIC);
+#endif
+      memset(&sNC, 0, sizeof(sNC));
+      sNC.pParse = pParse;
+
+      /* Push an entry on to the trigger stack */
+      trigStackEntry.pTrigger = p;
+      trigStackEntry.newIdx = newIdx;
+      trigStackEntry.oldIdx = oldIdx;
+      trigStackEntry.pTab = pTab;
+      trigStackEntry.pNext = pParse->trigStack;
+      trigStackEntry.ignoreJump = ignoreJump;
+      pParse->trigStack = &trigStackEntry;
+      sqlite3AuthContextPush(pParse, &sContext, p->name);
+
+      /* code the WHEN clause */
+      endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
+      whenExpr = sqlite3ExprDup(db, p->pWhen);
+      if( db->mallocFailed || sqlite3ExprResolveNames(&sNC, whenExpr) ){
+        pParse->trigStack = trigStackEntry.pNext;
+        sqlite3ExprDelete(whenExpr);
+        return 1;
+      }
+      sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
+      sqlite3ExprDelete(whenExpr);
+
+      codeTriggerProgram(pParse, p->step_list, orconf); 
+
+      /* Pop the entry off the trigger stack */
+      pParse->trigStack = trigStackEntry.pNext;
+      sqlite3AuthContextPop(&sContext);
+
+      sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
+    }
+  }
+  if( piOldColMask ) *piOldColMask |= trigStackEntry.oldColMask;
+  if( piNewColMask ) *piNewColMask |= trigStackEntry.newColMask;
+  return 0;
+}
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+
+/************** End of trigger.c *********************************************/
+/************** Begin file update.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle UPDATE statements.
+**
+** $Id: update.c,v 1.178 2008/04/28 18:46:43 drh Exp $
+*/
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Forward declaration */
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowidExpr,    /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere         /* WHERE clause of the UPDATE statement */
+);
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** The most recently coded instruction was an OP_Column to retrieve the
+** i-th column of table pTab. This routine sets the P4 parameter of the 
+** OP_Column to the default value, if any.
+**
+** The default value of a column is specified by a DEFAULT clause in the 
+** column definition. This was either supplied by the user when the table
+** was created, or added later to the table definition by an ALTER TABLE
+** command. If the latter, then the row-records in the table btree on disk
+** may not contain a value for the column and the default value, taken
+** from the P4 parameter of the OP_Column instruction, is returned instead.
+** If the former, then all row-records are guaranteed to include a value
+** for the column and the P4 value is not required.
+**
+** Column definitions created by an ALTER TABLE command may only have 
+** literal default values specified: a number, null or a string. (If a more
+** complicated default expression value was provided, it is evaluated 
+** when the ALTER TABLE is executed and one of the literal values written
+** into the sqlite_master table.)
+**
+** Therefore, the P4 parameter is only required if the default value for
+** the column is a literal number, string or null. The sqlite3ValueFromExpr()
+** function is capable of transforming these types of expressions into
+** sqlite3_value objects.
+*/
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
+  if( pTab && !pTab->pSelect ){
+    sqlite3_value *pValue;
+    u8 enc = ENC(sqlite3VdbeDb(v));
+    Column *pCol = &pTab->aCol[i];
+    VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
+    assert( i<pTab->nCol );
+    sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, 
+                         pCol->affinity, &pValue);
+    if( pValue ){
+      sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
+    }
+  }
+}
+
+/*
+** Process an UPDATE statement.
+**
+**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
+**          \_______/ \________/     \______/       \________________/
+*            onError   pTabList      pChanges             pWhere
+*/
+SQLITE_PRIVATE void sqlite3Update(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table in which we should change things */
+  ExprList *pChanges,    /* Things to be changed */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  int onError            /* How to handle constraint errors */
+){
+  int i, j;              /* Loop counters */
+  Table *pTab;           /* The table to be updated */
+  int addr = 0;          /* VDBE instruction address of the start of the loop */
+  WhereInfo *pWInfo;     /* Information about the WHERE clause */
+  Vdbe *v;               /* The virtual database engine */
+  Index *pIdx;           /* For looping over indices */
+  int nIdx;              /* Number of indices that need updating */
+  int iCur;              /* VDBE Cursor number of pTab */
+  sqlite3 *db;           /* The database structure */
+  int *aRegIdx = 0;      /* One register assigned to each index to be updated */
+  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
+                         ** an expression for the i-th column of the table.
+                         ** aXRef[i]==-1 if the i-th column is not changed. */
+  int chngRowid;         /* True if the record number is being changed */
+  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
+  int openAll = 0;       /* True if all indices need to be opened */
+  AuthContext sContext;  /* The authorization context */
+  NameContext sNC;       /* The name-context to resolve expressions in */
+  int iDb;               /* Database containing the table being updated */
+  int j1;                /* Addresses of jump instructions */
+  int okOnePass;         /* True for one-pass algorithm without the FIFO */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                  /* Trying to update a view */
+  int triggers_exist = 0;      /* True if any row triggers exist */
+#endif
+  int iBeginAfterTrigger;      /* Address of after trigger program */
+  int iEndAfterTrigger;        /* Exit of after trigger program */
+  int iBeginBeforeTrigger;     /* Address of before trigger program */
+  int iEndBeforeTrigger;       /* Exit of before trigger program */
+  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
+  u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */
+
+  int newIdx      = -1;  /* index of trigger "new" temp table       */
+  int oldIdx      = -1;  /* index of trigger "old" temp table       */
+
+  /* Register Allocations */
+  int regRowCount = 0;   /* A count of rows changed */
+  int regOldRowid;       /* The old rowid */
+  int regNewRowid;       /* The new rowid */
+  int regData;           /* New data for the row */
+
+  sContext.pParse = 0;
+  db = pParse->db;
+  if( pParse->nErr || db->mallocFailed ){
+    goto update_cleanup;
+  }
+  assert( pTabList->nSrc==1 );
+
+  /* Locate the table which we want to update. 
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ) goto update_cleanup;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+
+  /* Figure out if we have any triggers and if the table being
+  ** updated is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
+  isView = pTab->pSelect!=0;
+#else
+# define triggers_exist 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+    goto update_cleanup;
+  }
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto update_cleanup;
+  }
+  aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
+  if( aXRef==0 ) goto update_cleanup;
+  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
+
+  /* If there are FOR EACH ROW triggers, allocate cursors for the
+  ** special OLD and NEW tables
+  */
+  if( triggers_exist ){
+    newIdx = pParse->nTab++;
+    oldIdx = pParse->nTab++;
+  }
+
+  /* Allocate a cursors for the main database table and for all indices.
+  ** The index cursors might not be used, but if they are used they
+  ** need to occur right after the database cursor.  So go ahead and
+  ** allocate enough space, just in case.
+  */
+  pTabList->a[0].iCursor = iCur = pParse->nTab++;
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    pParse->nTab++;
+  }
+
+  /* Initialize the name-context */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+
+  /* Resolve the column names in all the expressions of the
+  ** of the UPDATE statement.  Also find the column index
+  ** for each column to be updated in the pChanges array.  For each
+  ** column to be updated, make sure we have authorization to change
+  ** that column.
+  */
+  chngRowid = 0;
+  for(i=0; i<pChanges->nExpr; i++){
+    if( sqlite3ExprResolveNames(&sNC, pChanges->a[i].pExpr) ){
+      goto update_cleanup;
+    }
+    for(j=0; j<pTab->nCol; j++){
+      if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
+        if( j==pTab->iPKey ){
+          chngRowid = 1;
+          pRowidExpr = pChanges->a[i].pExpr;
+        }
+        aXRef[j] = i;
+        break;
+      }
+    }
+    if( j>=pTab->nCol ){
+      if( sqlite3IsRowid(pChanges->a[i].zName) ){
+        chngRowid = 1;
+        pRowidExpr = pChanges->a[i].pExpr;
+      }else{
+        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
+        goto update_cleanup;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      int rc;
+      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
+                           pTab->aCol[j].zName, db->aDb[iDb].zName);
+      if( rc==SQLITE_DENY ){
+        goto update_cleanup;
+      }else if( rc==SQLITE_IGNORE ){
+        aXRef[j] = -1;
+      }
+    }
+#endif
+  }
+
+  /* Allocate memory for the array aRegIdx[].  There is one entry in the
+  ** array for each index associated with table being updated.  Fill in
+  ** the value with a register number for indices that are to be used
+  ** and with zero for unused indices.
+  */
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
+  if( nIdx>0 ){
+    aRegIdx = sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx );
+    if( aRegIdx==0 ) goto update_cleanup;
+  }
+  for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+    int reg;
+    if( chngRowid ){
+      reg = ++pParse->nMem;
+    }else{
+      reg = 0;
+      for(i=0; i<pIdx->nColumn; i++){
+        if( aXRef[pIdx->aiColumn[i]]>=0 ){
+          reg = ++pParse->nMem;
+          break;
+        }
+      }
+    }
+    aRegIdx[j] = reg;
+  }
+
+  /* Allocate a block of register used to store the change record
+  ** sent to sqlite3GenerateConstraintChecks().  There are either
+  ** one or two registers for holding the rowid.  One rowid register
+  ** is used if chngRowid is false and two are used if chngRowid is
+  ** true.  Following these are pTab->nCol register holding column
+  ** data.
+  */
+  regOldRowid = regNewRowid = pParse->nMem + 1;
+  pParse->nMem += pTab->nCol + 1;
+  if( chngRowid ){
+    regNewRowid++;
+    pParse->nMem++;
+  }
+  regData = regNewRowid+1;
+ 
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto update_cleanup;
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Virtual tables must be handled separately */
+  if( IsVirtual(pTab) ){
+    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
+                       pWhere);
+    pWhere = 0;
+    pTabList = 0;
+    goto update_cleanup;
+  }
+#endif
+
+  /* Start the view context
+  */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* Generate the code for triggers.
+  */
+  if( triggers_exist ){
+    int iGoto;
+
+    /* Create pseudo-tables for NEW and OLD
+    */
+    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
+    sqlite3VdbeAddOp2(v, OP_OpenPseudo, oldIdx, 0);
+    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
+    sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
+
+    iGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
+    addr = sqlite3VdbeMakeLabel(v);
+    iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
+    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
+          newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
+      goto update_cleanup;
+    }
+    iEndBeforeTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
+    iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
+    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, 
+          newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
+      goto update_cleanup;
+    }
+    iEndAfterTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
+    sqlite3VdbeJumpHere(v, iGoto);
+  }
+
+  /* If we are trying to update a view, realize that view into
+  ** a ephemeral table.
+  */
+  if( isView ){
+    sqlite3MaterializeView(pParse, pTab->pSelect, pWhere, iCur);
+  }
+
+  /* Resolve the column names in all the expressions in the
+  ** WHERE clause.
+  */
+  if( sqlite3ExprResolveNames(&sNC, pWhere) ){
+    goto update_cleanup;
+  }
+
+  /* Begin the database scan
+  */
+  sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
+  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
+                             WHERE_ONEPASS_DESIRED);
+  if( pWInfo==0 ) goto update_cleanup;
+  okOnePass = pWInfo->okOnePass;
+
+  /* Remember the rowid of every item to be updated.
+  */
+  sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
+  if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
+
+  /* End the database scan loop.
+  */
+  sqlite3WhereEnd(pWInfo);
+
+  /* Initialize the count of updated rows
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  if( !isView && !IsVirtual(pTab) ){
+    /* 
+    ** Open every index that needs updating.  Note that if any
+    ** index could potentially invoke a REPLACE conflict resolution 
+    ** action, then we need to open all indices because we might need
+    ** to be deleting some records.
+    */
+    if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
+    if( onError==OE_Replace ){
+      openAll = 1;
+    }else{
+      openAll = 0;
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        if( pIdx->onError==OE_Replace ){
+          openAll = 1;
+          break;
+        }
+      }
+    }
+    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+      if( openAll || aRegIdx[i]>0 ){
+        KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
+        sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
+                       (char*)pKey, P4_KEYINFO_HANDOFF);
+        assert( pParse->nTab>iCur+i+1 );
+      }
+    }
+  }
+  
+  /* Jump back to this point if a trigger encounters an IGNORE constraint. */
+  if( triggers_exist ){
+    sqlite3VdbeResolveLabel(v, addr);
+  }
+
+  /* Top of the update loop */
+  if( okOnePass ){
+    int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
+    addr = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, a1);
+  }else{
+    addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
+  }
+
+  if( triggers_exist ){
+    int regRowid;
+    int regRow;
+    int regCols;
+
+    /* Make cursor iCur point to the record that is being updated.
+    */
+    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
+
+    /* Generate the OLD table
+    */
+    regRowid = sqlite3GetTempReg(pParse);
+    regRow = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
+    if( !old_col_mask ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regRow);
+    }else{
+      sqlite3VdbeAddOp2(v, OP_RowData, iCur, regRow);
+    }
+    sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, regRow, regRowid);
+
+    /* Generate the NEW table
+    */
+    if( chngRowid ){
+      sqlite3ExprCodeAndCache(pParse, pRowidExpr, regRowid);
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
+    }
+    regCols = sqlite3GetTempRange(pParse, pTab->nCol);
+    for(i=0; i<pTab->nCol; i++){
+      if( i==pTab->iPKey ){
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
+        continue;
+      }
+      j = aXRef[i];
+      if( new_col_mask&((u32)1<<i) || new_col_mask==0xffffffff ){
+        if( j<0 ){
+          sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regCols+i);
+          sqlite3ColumnDefault(v, pTab, i);
+        }else{
+          sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr, regCols+i);
+        }
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
+      }
+    }
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRow);
+    if( !isView ){
+      sqlite3TableAffinityStr(v, pTab);
+      sqlite3ExprCacheAffinityChange(pParse, regCols, pTab->nCol);
+    }
+    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
+    if( pParse->nErr ) goto update_cleanup;
+    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRow, regRowid);
+    sqlite3ReleaseTempReg(pParse, regRowid);
+    sqlite3ReleaseTempReg(pParse, regRow);
+
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
+    sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
+  }
+
+  if( !isView && !IsVirtual(pTab) ){
+    /* Loop over every record that needs updating.  We have to load
+    ** the old data for each record to be updated because some columns
+    ** might not change and we will need to copy the old value.
+    ** Also, the old data is needed to delete the old index entries.
+    ** So make the cursor point at the old record.
+    */
+    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
+
+    /* If the record number will change, push the record number as it
+    ** will be after the update. (The old record number is currently
+    ** on top of the stack.)
+    */
+    if( chngRowid ){
+      sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
+    }
+
+    /* Compute new data for this record.  
+    */
+    for(i=0; i<pTab->nCol; i++){
+      if( i==pTab->iPKey ){
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i);
+        continue;
+      }
+      j = aXRef[i];
+      if( j<0 ){
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i);
+        sqlite3ColumnDefault(v, pTab, i);
+      }else{
+        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i);
+      }
+    }
+
+    /* Do constraint checks
+    */
+    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
+                                    aRegIdx, chngRowid, 1,
+                                    onError, addr);
+
+    /* Delete the old indices for the current record.
+    */
+    j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
+
+    /* If changing the record number, delete the old record.
+    */
+    if( chngRowid ){
+      sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
+    }
+    sqlite3VdbeJumpHere(v, j1);
+
+    /* Create the new index entries and the new record.
+    */
+    sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, 
+                             aRegIdx, chngRowid, 1, -1, 0);
+  }
+
+  /* Increment the row counter 
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  /* If there are triggers, close all the cursors after each iteration
+  ** through the loop.  The fire the after triggers.
+  */
+  if( triggers_exist ){
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
+    sqlite3VdbeJumpHere(v, iEndAfterTrigger);
+  }
+
+  /* Repeat the above with the next record to be updated, until
+  ** all record selected by the WHERE clause have been updated.
+  */
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+  sqlite3VdbeJumpHere(v, addr);
+
+  /* Close all tables */
+  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    if( openAll || aRegIdx[i]>0 ){
+      sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
+    }
+  }
+  sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
+  if( triggers_exist ){
+    sqlite3VdbeAddOp2(v, OP_Close, newIdx, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, oldIdx, 0);
+  }
+
+  /*
+  ** Return the number of rows that were changed. If this routine is 
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
+    sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC);
+  }
+
+update_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3_free(aRegIdx);
+  sqlite3_free(aXRef);
+  sqlite3SrcListDelete(pTabList);
+  sqlite3ExprListDelete(pChanges);
+  sqlite3ExprDelete(pWhere);
+  return;
+}
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Generate code for an UPDATE of a virtual table.
+**
+** The strategy is that we create an ephemerial table that contains
+** for each row to be changed:
+**
+**   (A)  The original rowid of that row.
+**   (B)  The revised rowid for the row. (note1)
+**   (C)  The content of every column in the row.
+**
+** Then we loop over this ephemeral table and for each row in
+** the ephermeral table call VUpdate.
+**
+** When finished, drop the ephemeral table.
+**
+** (note1) Actually, if we know in advance that (A) is always the same
+** as (B) we only store (A), then duplicate (A) when pulling
+** it out of the ephemeral table before calling VUpdate.
+*/
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowid,        /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere         /* WHERE clause of the UPDATE statement */
+){
+  Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
+  ExprList *pEList = 0;     /* The result set of the SELECT statement */
+  Select *pSelect = 0;      /* The SELECT statement */
+  Expr *pExpr;              /* Temporary expression */
+  int ephemTab;             /* Table holding the result of the SELECT */
+  int i;                    /* Loop counter */
+  int addr;                 /* Address of top of loop */
+  int iReg;                 /* First register in set passed to OP_VUpdate */
+  sqlite3 *db = pParse->db; /* Database connection */
+  const char *pVtab = (const char*)pTab->pVtab;
+  SelectDest dest;
+
+  /* Construct the SELECT statement that will find the new values for
+  ** all updated rows. 
+  */
+  pEList = sqlite3ExprListAppend(pParse, 0, 
+                                 sqlite3CreateIdExpr(pParse, "_rowid_"), 0);
+  if( pRowid ){
+    pEList = sqlite3ExprListAppend(pParse, pEList,
+                                   sqlite3ExprDup(db, pRowid), 0);
+  }
+  assert( pTab->iPKey<0 );
+  for(i=0; i<pTab->nCol; i++){
+    if( aXRef[i]>=0 ){
+      pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr);
+    }else{
+      pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
+    }
+    pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0);
+  }
+  pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
+  
+  /* Create the ephemeral table into which the update results will
+  ** be stored.
+  */
+  assert( v );
+  ephemTab = pParse->nTab++;
+  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
+
+  /* fill the ephemeral table 
+  */
+  sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
+  sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);
+
+  /* Generate code to scan the ephemeral table and call VUpdate. */
+  iReg = ++pParse->nMem;
+  pParse->nMem += pTab->nCol+1;
+  sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
+  addr = sqlite3VdbeCurrentAddr(v);
+  sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);
+  sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
+  for(i=0; i<pTab->nCol; i++){
+    sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
+  }
+  sqlite3VtabMakeWritable(pParse, pTab);
+  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVtab, P4_VTAB);
+  sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr);
+  sqlite3VdbeJumpHere(v, addr-1);
+  sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
+
+  /* Cleanup */
+  sqlite3SelectDelete(pSelect);  
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/* Make sure "isView" gets undefined in case this file becomes part of
+** the amalgamation - so that subsequent files do not see isView as a
+** macro. */
+#undef isView
+
+/************** End of update.c **********************************************/
+/************** Begin file vacuum.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the VACUUM command.
+**
+** Most of the code in this file may be omitted by defining the
+** SQLITE_OMIT_VACUUM macro.
+**
+** $Id: vacuum.c,v 1.78 2008/04/30 16:38:23 drh Exp $
+*/
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/*
+** Execute zSql on database db. Return an error code.
+*/
+static int execSql(sqlite3 *db, const char *zSql){
+  sqlite3_stmt *pStmt;
+  if( !zSql ){
+    return SQLITE_NOMEM;
+  }
+  if( SQLITE_OK!=sqlite3_prepare(db, zSql, -1, &pStmt, 0) ){
+    return sqlite3_errcode(db);
+  }
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){}
+  return sqlite3_finalize(pStmt);
+}
+
+/*
+** Execute zSql on database db. The statement returns exactly
+** one column. Execute this as SQL on the same database.
+*/
+static int execExecSql(sqlite3 *db, const char *zSql){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){
+    rc = execSql(db, (char*)sqlite3_column_text(pStmt, 0));
+    if( rc!=SQLITE_OK ){
+      sqlite3_finalize(pStmt);
+      return rc;
+    }
+  }
+
+  return sqlite3_finalize(pStmt);
+}
+
+/*
+** The non-standard VACUUM command is used to clean up the database,
+** collapse free space, etc.  It is modelled after the VACUUM command
+** in PostgreSQL.
+**
+** In version 1.0.x of SQLite, the VACUUM command would call
+** gdbm_reorganize() on all the database tables.  But beginning
+** with 2.0.0, SQLite no longer uses GDBM so this command has
+** become a no-op.
+*/
+SQLITE_PRIVATE void sqlite3Vacuum(Parse *pParse){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp2(v, OP_Vacuum, 0, 0);
+  }
+  return;
+}
+
+/*
+** This routine implements the OP_Vacuum opcode of the VDBE.
+*/
+SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
+  int rc = SQLITE_OK;     /* Return code from service routines */
+  Btree *pMain;           /* The database being vacuumed */
+  Btree *pTemp;           /* The temporary database we vacuum into */
+  char *zSql = 0;         /* SQL statements */
+  int saved_flags;        /* Saved value of the db->flags */
+  Db *pDb = 0;            /* Database to detach at end of vacuum */
+  int nRes;
+
+  /* Save the current value of the write-schema flag before setting it. */
+  saved_flags = db->flags;
+  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
+
+  if( !db->autoCommit ){
+    sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", 
+       (char*)0);
+    rc = SQLITE_ERROR;
+    goto end_of_vacuum;
+  }
+  pMain = db->aDb[0].pBt;
+
+  /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
+  ** can be set to 'off' for this file, as it is not recovered if a crash
+  ** occurs anyway. The integrity of the database is maintained by a
+  ** (possibly synchronous) transaction opened on the main database before
+  ** sqlite3BtreeCopyFile() is called.
+  **
+  ** An optimisation would be to use a non-journaled pager.
+  ** (Later:) I tried setting "PRAGMA vacuum_db.journal_mode=OFF" but
+  ** that actually made the VACUUM run slower.  Very little journalling
+  ** actually occurs when doing a vacuum since the vacuum_db is initially
+  ** empty.  Only the journal header is written.  Apparently it takes more
+  ** time to parse and run the PRAGMA to turn journalling off than it does
+  ** to write the journal header file.
+  */
+  zSql = "ATTACH '' AS vacuum_db;";
+  rc = execSql(db, zSql);
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  pDb = &db->aDb[db->nDb-1];
+  assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 );
+  pTemp = db->aDb[db->nDb-1].pBt;
+
+  nRes = sqlite3BtreeGetReserve(pMain);
+  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes)
+   || sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes)
+   || db->mallocFailed 
+  ){
+    rc = SQLITE_NOMEM;
+    goto end_of_vacuum;
+  }
+  rc = execSql(db, "PRAGMA vacuum_db.synchronous=OFF");
+  if( rc!=SQLITE_OK ){
+    goto end_of_vacuum;
+  }
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac :
+                                           sqlite3BtreeGetAutoVacuum(pMain));
+#endif
+
+  /* Begin a transaction */
+  rc = execSql(db, "BEGIN EXCLUSIVE;");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Query the schema of the main database. Create a mirror schema
+  ** in the temporary database.
+  */
+  rc = execExecSql(db, 
+      "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14) "
+      "  FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'"
+      "   AND rootpage>0"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14)"
+      "  FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' ");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21) "
+      "  FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Loop through the tables in the main database. For each, do
+  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy
+  ** the contents to the temporary database.
+  */
+  rc = execExecSql(db, 
+      "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
+      "|| ' SELECT * FROM ' || quote(name) || ';'"
+      "FROM sqlite_master "
+      "WHERE type = 'table' AND name!='sqlite_sequence' "
+      "  AND rootpage>0"
+
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Copy over the sequence table
+  */
+  rc = execExecSql(db, 
+      "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' "
+      "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' "
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
+      "|| ' SELECT * FROM ' || quote(name) || ';' "
+      "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+
+  /* Copy the triggers, views, and virtual tables from the main database
+  ** over to the temporary database.  None of these objects has any
+  ** associated storage, so all we have to do is copy their entries
+  ** from the SQLITE_MASTER table.
+  */
+  rc = execSql(db,
+      "INSERT INTO vacuum_db.sqlite_master "
+      "  SELECT type, name, tbl_name, rootpage, sql"
+      "    FROM sqlite_master"
+      "   WHERE type='view' OR type='trigger'"
+      "      OR (type='table' AND rootpage=0)"
+  );
+  if( rc ) goto end_of_vacuum;
+
+  /* At this point, unless the main db was completely empty, there is now a
+  ** transaction open on the vacuum database, but not on the main database.
+  ** Open a btree level transaction on the main database. This allows a
+  ** call to sqlite3BtreeCopyFile(). The main database btree level
+  ** transaction is then committed, so the SQL level never knows it was
+  ** opened for writing. This way, the SQL transaction used to create the
+  ** temporary database never needs to be committed.
+  */
+  if( rc==SQLITE_OK ){
+    u32 meta;
+    int i;
+
+    /* This array determines which meta meta values are preserved in the
+    ** vacuum.  Even entries are the meta value number and odd entries
+    ** are an increment to apply to the meta value after the vacuum.
+    ** The increment is used to increase the schema cookie so that other
+    ** connections to the same database will know to reread the schema.
+    */
+    static const unsigned char aCopy[] = {
+       1, 1,    /* Add one to the old schema cookie */
+       3, 0,    /* Preserve the default page cache size */
+       5, 0,    /* Preserve the default text encoding */
+       6, 0,    /* Preserve the user version */
+    };
+
+    assert( 1==sqlite3BtreeIsInTrans(pTemp) );
+    assert( 1==sqlite3BtreeIsInTrans(pMain) );
+
+    /* Copy Btree meta values */
+    for(i=0; i<sizeof(aCopy)/sizeof(aCopy[0]); i+=2){
+      rc = sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
+      if( rc!=SQLITE_OK ) goto end_of_vacuum;
+      rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
+      if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    }
+
+    rc = sqlite3BtreeCopyFile(pMain, pTemp);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    rc = sqlite3BtreeCommit(pTemp);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    rc = sqlite3BtreeCommit(pMain);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes);
+  }
+
+end_of_vacuum:
+  /* Restore the original value of db->flags */
+  db->flags = saved_flags;
+
+  /* Currently there is an SQL level transaction open on the vacuum
+  ** database. No locks are held on any other files (since the main file
+  ** was committed at the btree level). So it safe to end the transaction
+  ** by manually setting the autoCommit flag to true and detaching the
+  ** vacuum database. The vacuum_db journal file is deleted when the pager
+  ** is closed by the DETACH.
+  */
+  db->autoCommit = 1;
+
+  if( pDb ){
+    sqlite3BtreeClose(pDb->pBt);
+    pDb->pBt = 0;
+    pDb->pSchema = 0;
+  }
+
+  sqlite3ResetInternalSchema(db, 0);
+
+  return rc;
+}
+#endif  /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */
+
+/************** End of vacuum.c **********************************************/
+/************** Begin file vtab.c ********************************************/
+/*
+** 2006 June 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to help implement virtual tables.
+**
+** $Id: vtab.c,v 1.69 2008/05/05 13:23:04 drh Exp $
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+static int createModule(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+) {
+  int rc, nName;
+  Module *pMod;
+
+  sqlite3_mutex_enter(db->mutex);
+  nName = strlen(zName);
+  pMod = (Module *)sqlite3DbMallocRaw(db, sizeof(Module) + nName + 1);
+  if( pMod ){
+    char *zCopy = (char *)(&pMod[1]);
+    memcpy(zCopy, zName, nName+1);
+    pMod->zName = zCopy;
+    pMod->pModule = pModule;
+    pMod->pAux = pAux;
+    pMod->xDestroy = xDestroy;
+    pMod = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod);
+    if( pMod && pMod->xDestroy ){
+      pMod->xDestroy(pMod->pAux);
+    }
+    sqlite3_free(pMod);
+    sqlite3ResetInternalSchema(db, 0);
+  }
+  rc = sqlite3ApiExit(db, SQLITE_OK);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux                      /* Context pointer for xCreate/xConnect */
+){
+  return createModule(db, zName, pModule, pAux, 0);
+}
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+  return createModule(db, zName, pModule, pAux, xDestroy);
+}
+
+/*
+** Lock the virtual table so that it cannot be disconnected.
+** Locks nest.  Every lock should have a corresponding unlock.
+** If an unlock is omitted, resources leaks will occur.  
+**
+** If a disconnect is attempted while a virtual table is locked,
+** the disconnect is deferred until all locks have been removed.
+*/
+SQLITE_PRIVATE void sqlite3VtabLock(sqlite3_vtab *pVtab){
+  pVtab->nRef++;
+}
+
+/*
+** Unlock a virtual table.  When the last lock is removed,
+** disconnect the virtual table.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlock(sqlite3 *db, sqlite3_vtab *pVtab){
+  pVtab->nRef--;
+  assert(db);
+  assert( sqlite3SafetyCheckOk(db) );
+  if( pVtab->nRef==0 ){
+    if( db->magic==SQLITE_MAGIC_BUSY ){
+      (void)sqlite3SafetyOff(db);
+      pVtab->pModule->xDisconnect(pVtab);
+      (void)sqlite3SafetyOn(db);
+    } else {
+      pVtab->pModule->xDisconnect(pVtab);
+    }
+  }
+}
+
+/*
+** Clear any and all virtual-table information from the Table record.
+** This routine is called, for example, just before deleting the Table
+** record.
+*/
+SQLITE_PRIVATE void sqlite3VtabClear(Table *p){
+  sqlite3_vtab *pVtab = p->pVtab;
+  if( pVtab ){
+    assert( p->pMod && p->pMod->pModule );
+    sqlite3VtabUnlock(p->pSchema->db, pVtab);
+    p->pVtab = 0;
+  }
+  if( p->azModuleArg ){
+    int i;
+    for(i=0; i<p->nModuleArg; i++){
+      sqlite3_free(p->azModuleArg[i]);
+    }
+    sqlite3_free(p->azModuleArg);
+  }
+}
+
+/*
+** Add a new module argument to pTable->azModuleArg[].
+** The string is not copied - the pointer is stored.  The
+** string will be freed automatically when the table is
+** deleted.
+*/
+static void addModuleArgument(sqlite3 *db, Table *pTable, char *zArg){
+  int i = pTable->nModuleArg++;
+  int nBytes = sizeof(char *)*(1+pTable->nModuleArg);
+  char **azModuleArg;
+  azModuleArg = sqlite3DbRealloc(db, pTable->azModuleArg, nBytes);
+  if( azModuleArg==0 ){
+    int j;
+    for(j=0; j<i; j++){
+      sqlite3_free(pTable->azModuleArg[j]);
+    }
+    sqlite3_free(zArg);
+    sqlite3_free(pTable->azModuleArg);
+    pTable->nModuleArg = 0;
+  }else{
+    azModuleArg[i] = zArg;
+    azModuleArg[i+1] = 0;
+  }
+  pTable->azModuleArg = azModuleArg;
+}
+
+/*
+** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE
+** statement.  The module name has been parsed, but the optional list
+** of parameters that follow the module name are still pending.
+*/
+SQLITE_PRIVATE void sqlite3VtabBeginParse(
+  Parse *pParse,        /* Parsing context */
+  Token *pName1,        /* Name of new table, or database name */
+  Token *pName2,        /* Name of new table or NULL */
+  Token *pModuleName    /* Name of the module for the virtual table */
+){
+  int iDb;              /* The database the table is being created in */
+  Table *pTable;        /* The new virtual table */
+  sqlite3 *db;          /* Database connection */
+
+  if( pParse->db->flags & SQLITE_SharedCache ){
+    sqlite3ErrorMsg(pParse, "Cannot use virtual tables in shared-cache mode");
+    return;
+  }
+
+  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, 0);
+  pTable = pParse->pNewTable;
+  if( pTable==0 || pParse->nErr ) return;
+  assert( 0==pTable->pIndex );
+
+  db = pParse->db;
+  iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
+  assert( iDb>=0 );
+
+  pTable->isVirtual = 1;
+  pTable->nModuleArg = 0;
+  addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName));
+  addModuleArgument(db, pTable, sqlite3DbStrDup(db, db->aDb[iDb].zName));
+  addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName));
+  pParse->sNameToken.n = pModuleName->z + pModuleName->n - pName1->z;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Creating a virtual table invokes the authorization callback twice.
+  ** The first invocation, to obtain permission to INSERT a row into the
+  ** sqlite_master table, has already been made by sqlite3StartTable().
+  ** The second call, to obtain permission to create the table, is made now.
+  */
+  if( pTable->azModuleArg ){
+    sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName, 
+            pTable->azModuleArg[0], pParse->db->aDb[iDb].zName);
+  }
+#endif
+}
+
+/*
+** This routine takes the module argument that has been accumulating
+** in pParse->zArg[] and appends it to the list of arguments on the
+** virtual table currently under construction in pParse->pTable.
+*/
+static void addArgumentToVtab(Parse *pParse){
+  if( pParse->sArg.z && pParse->pNewTable ){
+    const char *z = (const char*)pParse->sArg.z;
+    int n = pParse->sArg.n;
+    sqlite3 *db = pParse->db;
+    addModuleArgument(db, pParse->pNewTable, sqlite3DbStrNDup(db, z, n));
+  }
+}
+
+/*
+** The parser calls this routine after the CREATE VIRTUAL TABLE statement
+** has been completely parsed.
+*/
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
+  Table *pTab;        /* The table being constructed */
+  sqlite3 *db;        /* The database connection */
+  char *zModule;      /* The module name of the table: USING modulename */
+  Module *pMod = 0;
+
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+
+  /* Lookup the module name. */
+  pTab = pParse->pNewTable;
+  if( pTab==0 ) return;
+  db = pParse->db;
+  if( pTab->nModuleArg<1 ) return;
+  zModule = pTab->azModuleArg[0];
+  pMod = (Module *)sqlite3HashFind(&db->aModule, zModule, strlen(zModule));
+  pTab->pMod = pMod;
+  
+  /* If the CREATE VIRTUAL TABLE statement is being entered for the
+  ** first time (in other words if the virtual table is actually being
+  ** created now instead of just being read out of sqlite_master) then
+  ** do additional initialization work and store the statement text
+  ** in the sqlite_master table.
+  */
+  if( !db->init.busy ){
+    char *zStmt;
+    char *zWhere;
+    int iDb;
+    Vdbe *v;
+
+    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
+    if( pEnd ){
+      pParse->sNameToken.n = pEnd->z - pParse->sNameToken.z + pEnd->n;
+    }
+    zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken);
+
+    /* A slot for the record has already been allocated in the 
+    ** SQLITE_MASTER table.  We just need to update that slot with all
+    ** the information we've collected.  
+    **
+    ** The VM register number pParse->regRowid holds the rowid of an
+    ** entry in the sqlite_master table tht was created for this vtab
+    ** by sqlite3StartTable().
+    */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q.%s "
+         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
+       "WHERE rowid=#%d",
+      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
+      pTab->zName,
+      pTab->zName,
+      zStmt,
+      pParse->regRowid
+    );
+    sqlite3_free(zStmt);
+    v = sqlite3GetVdbe(pParse);
+    sqlite3ChangeCookie(pParse, iDb);
+
+    sqlite3VdbeAddOp2(v, OP_Expire, 0, 0);
+    zWhere = sqlite3MPrintf(db, "name='%q'", pTab->zName);
+    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 1, 0, zWhere, P4_DYNAMIC);
+    sqlite3VdbeAddOp4(v, OP_VCreate, iDb, 0, 0, 
+                         pTab->zName, strlen(pTab->zName) + 1);
+  }
+
+  /* If we are rereading the sqlite_master table create the in-memory
+  ** record of the table. If the module has already been registered,
+  ** also call the xConnect method here.
+  */
+  else {
+    Table *pOld;
+    Schema *pSchema = pTab->pSchema;
+    const char *zName = pTab->zName;
+    int nName = strlen(zName) + 1;
+    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab);
+    if( pOld ){
+      db->mallocFailed = 1;
+      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
+      return;
+    }
+    pSchema->db = pParse->db;
+    pParse->pNewTable = 0;
+  }
+}
+
+/*
+** The parser calls this routine when it sees the first token
+** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse *pParse){
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  pParse->sArg.n = 0;
+}
+
+/*
+** The parser calls this routine for each token after the first token
+** in an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse *pParse, Token *p){
+  Token *pArg = &pParse->sArg;
+  if( pArg->z==0 ){
+    pArg->z = p->z;
+    pArg->n = p->n;
+  }else{
+    assert(pArg->z < p->z);
+    pArg->n = (p->z + p->n - pArg->z);
+  }
+}
+
+/*
+** Invoke a virtual table constructor (either xCreate or xConnect). The
+** pointer to the function to invoke is passed as the fourth parameter
+** to this procedure.
+*/
+static int vtabCallConstructor(
+  sqlite3 *db, 
+  Table *pTab,
+  Module *pMod,
+  int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
+  char **pzErr
+){
+  int rc;
+  int rc2;
+  sqlite3_vtab *pVtab = 0;
+  const char *const*azArg = (const char *const*)pTab->azModuleArg;
+  int nArg = pTab->nModuleArg;
+  char *zErr = 0;
+  char *zModuleName = sqlite3MPrintf(db, "%s", pTab->zName);
+
+  if( !zModuleName ){
+    return SQLITE_NOMEM;
+  }
+
+  assert( !db->pVTab );
+  assert( xConstruct );
+
+  db->pVTab = pTab;
+  rc = sqlite3SafetyOff(db);
+  assert( rc==SQLITE_OK );
+  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVtab, &zErr);
+  rc2 = sqlite3SafetyOn(db);
+  if( rc==SQLITE_OK && pVtab ){
+    pVtab->pModule = pMod->pModule;
+    pVtab->nRef = 1;
+    pTab->pVtab = pVtab;
+  }
+
+  if( SQLITE_OK!=rc ){
+    if( zErr==0 ){
+      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
+    }else {
+      *pzErr = sqlite3MPrintf(db, "%s", zErr);
+      sqlite3_free(zErr);
+    }
+  }else if( db->pVTab ){
+    const char *zFormat = "vtable constructor did not declare schema: %s";
+    *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
+    rc = SQLITE_ERROR;
+  } 
+  if( rc==SQLITE_OK ){
+    rc = rc2;
+  }
+  db->pVTab = 0;
+  sqlite3_free(zModuleName);
+
+  /* If everything went according to plan, loop through the columns
+  ** of the table to see if any of them contain the token "hidden".
+  ** If so, set the Column.isHidden flag and remove the token from
+  ** the type string.
+  */
+  if( rc==SQLITE_OK ){
+    int iCol;
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      char *zType = pTab->aCol[iCol].zType;
+      int nType;
+      int i = 0;
+      if( !zType ) continue;
+      nType = strlen(zType);
+      if( sqlite3StrNICmp("hidden", zType, 6) || (zType[6] && zType[6]!=' ') ){
+        for(i=0; i<nType; i++){
+          if( (0==sqlite3StrNICmp(" hidden", &zType[i], 7))
+           && (zType[i+7]=='\0' || zType[i+7]==' ')
+          ){
+            i++;
+            break;
+          }
+        }
+      }
+      if( i<nType ){
+        int j;
+        int nDel = 6 + (zType[i+6] ? 1 : 0);
+        for(j=i; (j+nDel)<=nType; j++){
+          zType[j] = zType[j+nDel];
+        }
+        if( zType[i]=='\0' && i>0 ){
+          assert(zType[i-1]==' ');
+          zType[i-1] = '\0';
+        }
+        pTab->aCol[iCol].isHidden = 1;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is invoked by the parser to call the xConnect() method
+** of the virtual table pTab. If an error occurs, an error code is returned 
+** and an error left in pParse.
+**
+** This call is a no-op if table pTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
+  Module *pMod;
+  int rc = SQLITE_OK;
+
+  if( !pTab || !pTab->isVirtual || pTab->pVtab ){
+    return SQLITE_OK;
+  }
+
+  pMod = pTab->pMod;
+  if( !pMod ){
+    const char *zModule = pTab->azModuleArg[0];
+    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  } else {
+    char *zErr = 0;
+    sqlite3 *db = pParse->db;
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "%s", zErr);
+    }
+    sqlite3_free(zErr);
+  }
+
+  return rc;
+}
+
+/*
+** Add the virtual table pVtab to the array sqlite3.aVTrans[].
+*/
+static int addToVTrans(sqlite3 *db, sqlite3_vtab *pVtab){
+  const int ARRAY_INCR = 5;
+
+  /* Grow the sqlite3.aVTrans array if required */
+  if( (db->nVTrans%ARRAY_INCR)==0 ){
+    sqlite3_vtab **aVTrans;
+    int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR);
+    aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
+    if( !aVTrans ){
+      return SQLITE_NOMEM;
+    }
+    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
+    db->aVTrans = aVTrans;
+  }
+
+  /* Add pVtab to the end of sqlite3.aVTrans */
+  db->aVTrans[db->nVTrans++] = pVtab;
+  sqlite3VtabLock(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** This function is invoked by the vdbe to call the xCreate method
+** of the virtual table named zTab in database iDb. 
+**
+** If an error occurs, *pzErr is set to point an an English language
+** description of the error and an SQLITE_XXX error code is returned.
+** In this case the caller must call sqlite3_free() on *pzErr.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Module *pMod;
+  const char *zModule;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
+  assert(pTab && pTab->isVirtual && !pTab->pVtab);
+  pMod = pTab->pMod;
+  zModule = pTab->azModuleArg[0];
+
+  /* If the module has been registered and includes a Create method, 
+  ** invoke it now. If the module has not been registered, return an 
+  ** error. Otherwise, do nothing.
+  */
+  if( !pMod ){
+    *pzErr = sqlite3MPrintf(db, "no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  }else{
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
+  }
+
+  if( rc==SQLITE_OK && pTab->pVtab ){
+      rc = addToVTrans(db, pTab->pVtab);
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to set the schema of a virtual table.  It is only
+** valid to call this function from within the xCreate() or xConnect() of a
+** virtual table module.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
+  Parse sParse;
+
+  int rc = SQLITE_OK;
+  Table *pTab;
+  char *zErr = 0;
+
+  sqlite3_mutex_enter(db->mutex);
+  pTab = db->pVTab;
+  if( !pTab ){
+    sqlite3Error(db, SQLITE_MISUSE, 0);
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_MISUSE;
+  }
+  assert(pTab->isVirtual && pTab->nCol==0 && pTab->aCol==0);
+
+  memset(&sParse, 0, sizeof(Parse));
+  sParse.declareVtab = 1;
+  sParse.db = db;
+
+  if( 
+      SQLITE_OK == sqlite3RunParser(&sParse, zCreateTable, &zErr) && 
+      sParse.pNewTable && 
+      !sParse.pNewTable->pSelect && 
+      !sParse.pNewTable->isVirtual 
+  ){
+    pTab->aCol = sParse.pNewTable->aCol;
+    pTab->nCol = sParse.pNewTable->nCol;
+    sParse.pNewTable->nCol = 0;
+    sParse.pNewTable->aCol = 0;
+    db->pVTab = 0;
+  } else {
+    sqlite3Error(db, SQLITE_ERROR, zErr);
+    sqlite3_free(zErr);
+    rc = SQLITE_ERROR;
+  }
+  sParse.declareVtab = 0;
+
+  sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
+  sqlite3DeleteTable(sParse.pNewTable);
+  sParse.pNewTable = 0;
+
+  assert( (rc&0xff)==rc );
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is invoked by the vdbe to call the xDestroy method
+** of the virtual table named zTab in database iDb. This occurs
+** when a DROP TABLE is mentioned.
+**
+** This call is a no-op if zTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab)
+{
+  int rc = SQLITE_OK;
+  Table *pTab;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
+  assert(pTab);
+  if( pTab->pVtab ){
+    int (*xDestroy)(sqlite3_vtab *pVTab) = pTab->pMod->pModule->xDestroy;
+    rc = sqlite3SafetyOff(db);
+    assert( rc==SQLITE_OK );
+    if( xDestroy ){
+      rc = xDestroy(pTab->pVtab);
+    }
+    (void)sqlite3SafetyOn(db);
+    if( rc==SQLITE_OK ){
+      int i;
+      for(i=0; i<db->nVTrans; i++){
+        if( db->aVTrans[i]==pTab->pVtab ){
+          db->aVTrans[i] = db->aVTrans[--db->nVTrans];
+          break;
+        }
+      }
+      pTab->pVtab = 0;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function invokes either the xRollback or xCommit method
+** of each of the virtual tables in the sqlite3.aVTrans array. The method
+** called is identified by the second argument, "offset", which is
+** the offset of the method to call in the sqlite3_module structure.
+**
+** The array is cleared after invoking the callbacks. 
+*/
+static void callFinaliser(sqlite3 *db, int offset){
+  int i;
+  if( db->aVTrans ){
+    for(i=0; i<db->nVTrans && db->aVTrans[i]; i++){
+      sqlite3_vtab *pVtab = db->aVTrans[i];
+      int (*x)(sqlite3_vtab *);
+      x = *(int (**)(sqlite3_vtab *))((char *)pVtab->pModule + offset);
+      if( x ) x(pVtab);
+      sqlite3VtabUnlock(db, pVtab);
+    }
+    sqlite3_free(db->aVTrans);
+    db->nVTrans = 0;
+    db->aVTrans = 0;
+  }
+}
+
+/*
+** If argument rc2 is not SQLITE_OK, then return it and do nothing. 
+** Otherwise, invoke the xSync method of all virtual tables in the 
+** sqlite3.aVTrans array. Return the error code for the first error 
+** that occurs, or SQLITE_OK if all xSync operations are successful.
+*/
+SQLITE_PRIVATE int sqlite3VtabSync(sqlite3 *db, int rc2){
+  int i;
+  int rc = SQLITE_OK;
+  int rcsafety;
+  sqlite3_vtab **aVTrans = db->aVTrans;
+  if( rc2!=SQLITE_OK ) return rc2;
+
+  rc = sqlite3SafetyOff(db);
+  db->aVTrans = 0;
+  for(i=0; rc==SQLITE_OK && i<db->nVTrans && aVTrans[i]; i++){
+    sqlite3_vtab *pVtab = aVTrans[i];
+    int (*x)(sqlite3_vtab *);
+    x = pVtab->pModule->xSync;
+    if( x ){
+      rc = x(pVtab);
+    }
+  }
+  db->aVTrans = aVTrans;
+  rcsafety = sqlite3SafetyOn(db);
+
+  if( rc==SQLITE_OK ){
+    rc = rcsafety;
+  }
+  return rc;
+}
+
+/*
+** Invoke the xRollback method of all virtual tables in the 
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabRollback(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xRollback));
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xCommit method of all virtual tables in the 
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabCommit(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xCommit));
+  return SQLITE_OK;
+}
+
+/*
+** If the virtual table pVtab supports the transaction interface
+** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
+** not currently open, invoke the xBegin method now.
+**
+** If the xBegin call is successful, place the sqlite3_vtab pointer
+** in the sqlite3.aVTrans array.
+*/
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, sqlite3_vtab *pVtab){
+  int rc = SQLITE_OK;
+  const sqlite3_module *pModule;
+
+  /* Special case: If db->aVTrans is NULL and db->nVTrans is greater
+  ** than zero, then this function is being called from within a
+  ** virtual module xSync() callback. It is illegal to write to 
+  ** virtual module tables in this case, so return SQLITE_LOCKED.
+  */
+  if( 0==db->aVTrans && db->nVTrans>0 ){
+    return SQLITE_LOCKED;
+  }
+  if( !pVtab ){
+    return SQLITE_OK;
+  } 
+  pModule = pVtab->pModule;
+
+  if( pModule->xBegin ){
+    int i;
+
+
+    /* If pVtab is already in the aVTrans array, return early */
+    for(i=0; (i<db->nVTrans) && 0!=db->aVTrans[i]; i++){
+      if( db->aVTrans[i]==pVtab ){
+        return SQLITE_OK;
+      }
+    }
+
+    /* Invoke the xBegin method */
+    rc = pModule->xBegin(pVtab);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    rc = addToVTrans(db, pVtab);
+  }
+  return rc;
+}
+
+/*
+** The first parameter (pDef) is a function implementation.  The
+** second parameter (pExpr) is the first argument to this function.
+** If pExpr is a column in a virtual table, then let the virtual
+** table implementation have an opportunity to overload the function.
+**
+** This routine is used to allow virtual table implementations to
+** overload MATCH, LIKE, GLOB, and REGEXP operators.
+**
+** Return either the pDef argument (indicating no change) or a 
+** new FuncDef structure that is marked as ephemeral using the
+** SQLITE_FUNC_EPHEM flag.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
+  sqlite3 *db,    /* Database connection for reporting malloc problems */
+  FuncDef *pDef,  /* Function to possibly overload */
+  int nArg,       /* Number of arguments to the function */
+  Expr *pExpr     /* First argument to the function */
+){
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pMod;
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  void *pArg;
+  FuncDef *pNew;
+  int rc = 0;
+  char *zLowerName;
+  unsigned char *z;
+
+
+  /* Check to see the left operand is a column in a virtual table */
+  if( pExpr==0 ) return pDef;
+  if( pExpr->op!=TK_COLUMN ) return pDef;
+  pTab = pExpr->pTab;
+  if( pTab==0 ) return pDef;
+  if( !pTab->isVirtual ) return pDef;
+  pVtab = pTab->pVtab;
+  assert( pVtab!=0 );
+  assert( pVtab->pModule!=0 );
+  pMod = (sqlite3_module *)pVtab->pModule;
+  if( pMod->xFindFunction==0 ) return pDef;
+ 
+  /* Call the xFindFunction method on the virtual table implementation
+  ** to see if the implementation wants to overload this function 
+  */
+  zLowerName = sqlite3DbStrDup(db, pDef->zName);
+  if( zLowerName ){
+    for(z=(unsigned char*)zLowerName; *z; z++){
+      *z = sqlite3UpperToLower[*z];
+    }
+    rc = pMod->xFindFunction(pVtab, nArg, zLowerName, &xFunc, &pArg);
+    sqlite3_free(zLowerName);
+  }
+  if( rc==0 ){
+    return pDef;
+  }
+
+  /* Create a new ephemeral function definition for the overloaded
+  ** function */
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew) + strlen(pDef->zName) );
+  if( pNew==0 ){
+    return pDef;
+  }
+  *pNew = *pDef;
+  memcpy(pNew->zName, pDef->zName, strlen(pDef->zName)+1);
+  pNew->xFunc = xFunc;
+  pNew->pUserData = pArg;
+  pNew->flags |= SQLITE_FUNC_EPHEM;
+  return pNew;
+}
+
+/*
+** Make sure virtual table pTab is contained in the pParse->apVirtualLock[]
+** array so that an OP_VBegin will get generated for it.  Add pTab to the
+** array if it is missing.  If pTab is already in the array, this routine
+** is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
+  int i, n;
+  assert( IsVirtual(pTab) );
+  for(i=0; i<pParse->nVtabLock; i++){
+    if( pTab==pParse->apVtabLock[i] ) return;
+  }
+  n = (pParse->nVtabLock+1)*sizeof(pParse->apVtabLock[0]);
+  pParse->apVtabLock = sqlite3_realloc(pParse->apVtabLock, n);
+  if( pParse->apVtabLock ){
+    pParse->apVtabLock[pParse->nVtabLock++] = pTab;
+  }else{
+    pParse->db->mallocFailed = 1;
+  }
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/************** End of vtab.c ************************************************/
+/************** Begin file where.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.  This module is reponsible for
+** generating the code that loops through a table looking for applicable
+** rows.  Indices are selected and used to speed the search when doing
+** so is applicable.  Because this module is responsible for selecting
+** indices, you might also think of this module as the "query optimizer".
+**
+** $Id: where.c,v 1.302 2008/04/19 14:40:44 drh Exp $
+*/
+
+/*
+** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
+*/
+#define BMS  (sizeof(Bitmask)*8)
+
+/*
+** Trace output macros
+*/
+#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3WhereTrace = 0;
+# define WHERETRACE(X)  if(sqlite3WhereTrace) sqlite3DebugPrintf X
+#else
+# define WHERETRACE(X)
+#endif
+
+/* Forward reference
+*/
+typedef struct WhereClause WhereClause;
+typedef struct ExprMaskSet ExprMaskSet;
+
+/*
+** The query generator uses an array of instances of this structure to
+** help it analyze the subexpressions of the WHERE clause.  Each WHERE
+** clause subexpression is separated from the others by an AND operator.
+**
+** All WhereTerms are collected into a single WhereClause structure.  
+** The following identity holds:
+**
+**        WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
+**
+** When a term is of the form:
+**
+**              X <op> <expr>
+**
+** where X is a column name and <op> is one of certain operators,
+** then WhereTerm.leftCursor and WhereTerm.leftColumn record the
+** cursor number and column number for X.  WhereTerm.operator records
+** the <op> using a bitmask encoding defined by WO_xxx below.  The
+** use of a bitmask encoding for the operator allows us to search
+** quickly for terms that match any of several different operators.
+**
+** prereqRight and prereqAll record sets of cursor numbers,
+** but they do so indirectly.  A single ExprMaskSet structure translates
+** cursor number into bits and the translated bit is stored in the prereq
+** fields.  The translation is used in order to maximize the number of
+** bits that will fit in a Bitmask.  The VDBE cursor numbers might be
+** spread out over the non-negative integers.  For example, the cursor
+** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45.  The ExprMaskSet
+** translates these sparse cursor numbers into consecutive integers
+** beginning with 0 in order to make the best possible use of the available
+** bits in the Bitmask.  So, in the example above, the cursor numbers
+** would be mapped into integers 0 through 7.
+*/
+typedef struct WhereTerm WhereTerm;
+struct WhereTerm {
+  Expr *pExpr;            /* Pointer to the subexpression */
+  i16 iParent;            /* Disable pWC->a[iParent] when this term disabled */
+  i16 leftCursor;         /* Cursor number of X in "X <op> <expr>" */
+  i16 leftColumn;         /* Column number of X in "X <op> <expr>" */
+  u16 eOperator;          /* A WO_xx value describing <op> */
+  u8 flags;               /* Bit flags.  See below */
+  u8 nChild;              /* Number of children that must disable us */
+  WhereClause *pWC;       /* The clause this term is part of */
+  Bitmask prereqRight;    /* Bitmask of tables used by pRight */
+  Bitmask prereqAll;      /* Bitmask of tables referenced by p */
+};
+
+/*
+** Allowed values of WhereTerm.flags
+*/
+#define TERM_DYNAMIC    0x01   /* Need to call sqlite3ExprDelete(pExpr) */
+#define TERM_VIRTUAL    0x02   /* Added by the optimizer.  Do not code */
+#define TERM_CODED      0x04   /* This term is already coded */
+#define TERM_COPIED     0x08   /* Has a child */
+#define TERM_OR_OK      0x10   /* Used during OR-clause processing */
+
+/*
+** An instance of the following structure holds all information about a
+** WHERE clause.  Mostly this is a container for one or more WhereTerms.
+*/
+struct WhereClause {
+  Parse *pParse;           /* The parser context */
+  ExprMaskSet *pMaskSet;   /* Mapping of table indices to bitmasks */
+  int nTerm;               /* Number of terms */
+  int nSlot;               /* Number of entries in a[] */
+  WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
+  WhereTerm aStatic[10];   /* Initial static space for a[] */
+};
+
+/*
+** An instance of the following structure keeps track of a mapping
+** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
+**
+** The VDBE cursor numbers are small integers contained in 
+** SrcList_item.iCursor and Expr.iTable fields.  For any given WHERE 
+** clause, the cursor numbers might not begin with 0 and they might
+** contain gaps in the numbering sequence.  But we want to make maximum
+** use of the bits in our bitmasks.  This structure provides a mapping
+** from the sparse cursor numbers into consecutive integers beginning
+** with 0.
+**
+** If ExprMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
+** corresponds VDBE cursor number B.  The A-th bit of a bitmask is 1<<A.
+**
+** For example, if the WHERE clause expression used these VDBE
+** cursors:  4, 5, 8, 29, 57, 73.  Then the  ExprMaskSet structure
+** would map those cursor numbers into bits 0 through 5.
+**
+** Note that the mapping is not necessarily ordered.  In the example
+** above, the mapping might go like this:  4->3, 5->1, 8->2, 29->0,
+** 57->5, 73->4.  Or one of 719 other combinations might be used. It
+** does not really matter.  What is important is that sparse cursor
+** numbers all get mapped into bit numbers that begin with 0 and contain
+** no gaps.
+*/
+struct ExprMaskSet {
+  int n;                        /* Number of assigned cursor values */
+  int ix[sizeof(Bitmask)*8];    /* Cursor assigned to each bit */
+};
+
+
+/*
+** Bitmasks for the operators that indices are able to exploit.  An
+** OR-ed combination of these values can be used when searching for
+** terms in the where clause.
+*/
+#define WO_IN     1
+#define WO_EQ     2
+#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
+#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
+#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
+#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
+#define WO_MATCH  64
+#define WO_ISNULL 128
+
+/*
+** Value for flags returned by bestIndex().  
+**
+** The least significant byte is reserved as a mask for WO_ values above.
+** The WhereLevel.flags field is usually set to WO_IN|WO_EQ|WO_ISNULL.
+** But if the table is the right table of a left join, WhereLevel.flags
+** is set to WO_IN|WO_EQ.  The WhereLevel.flags field can then be used as
+** the "op" parameter to findTerm when we are resolving equality constraints.
+** ISNULL constraints will then not be used on the right table of a left
+** join.  Tickets #2177 and #2189.
+*/
+#define WHERE_ROWID_EQ     0x000100   /* rowid=EXPR or rowid IN (...) */
+#define WHERE_ROWID_RANGE  0x000200   /* rowid<EXPR and/or rowid>EXPR */
+#define WHERE_COLUMN_EQ    0x001000   /* x=EXPR or x IN (...) */
+#define WHERE_COLUMN_RANGE 0x002000   /* x<EXPR and/or x>EXPR */
+#define WHERE_COLUMN_IN    0x004000   /* x IN (...) */
+#define WHERE_TOP_LIMIT    0x010000   /* x<EXPR or x<=EXPR constraint */
+#define WHERE_BTM_LIMIT    0x020000   /* x>EXPR or x>=EXPR constraint */
+#define WHERE_IDX_ONLY     0x080000   /* Use index only - omit table */
+#define WHERE_ORDERBY      0x100000   /* Output will appear in correct order */
+#define WHERE_REVERSE      0x200000   /* Scan in reverse order */
+#define WHERE_UNIQUE       0x400000   /* Selects no more than one row */
+#define WHERE_VIRTUALTABLE 0x800000   /* Use virtual-table processing */
+
+/*
+** Initialize a preallocated WhereClause structure.
+*/
+static void whereClauseInit(
+  WhereClause *pWC,        /* The WhereClause to be initialized */
+  Parse *pParse,           /* The parsing context */
+  ExprMaskSet *pMaskSet    /* Mapping from table indices to bitmasks */
+){
+  pWC->pParse = pParse;
+  pWC->pMaskSet = pMaskSet;
+  pWC->nTerm = 0;
+  pWC->nSlot = ArraySize(pWC->aStatic);
+  pWC->a = pWC->aStatic;
+}
+
+/*
+** Deallocate a WhereClause structure.  The WhereClause structure
+** itself is not freed.  This routine is the inverse of whereClauseInit().
+*/
+static void whereClauseClear(WhereClause *pWC){
+  int i;
+  WhereTerm *a;
+  for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
+    if( a->flags & TERM_DYNAMIC ){
+      sqlite3ExprDelete(a->pExpr);
+    }
+  }
+  if( pWC->a!=pWC->aStatic ){
+    sqlite3_free(pWC->a);
+  }
+}
+
+/*
+** Add a new entries to the WhereClause structure.  Increase the allocated
+** space as necessary.
+**
+** If the flags argument includes TERM_DYNAMIC, then responsibility
+** for freeing the expression p is assumed by the WhereClause object.
+**
+** WARNING:  This routine might reallocate the space used to store
+** WhereTerms.  All pointers to WhereTerms should be invalided after
+** calling this routine.  Such pointers may be reinitialized by referencing
+** the pWC->a[] array.
+*/
+static int whereClauseInsert(WhereClause *pWC, Expr *p, int flags){
+  WhereTerm *pTerm;
+  int idx;
+  if( pWC->nTerm>=pWC->nSlot ){
+    WhereTerm *pOld = pWC->a;
+    pWC->a = sqlite3_malloc( sizeof(pWC->a[0])*pWC->nSlot*2 );
+    if( pWC->a==0 ){
+      pWC->pParse->db->mallocFailed = 1;
+      if( flags & TERM_DYNAMIC ){
+        sqlite3ExprDelete(p);
+      }
+      pWC->a = pOld;
+      return 0;
+    }
+    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
+    if( pOld!=pWC->aStatic ){
+      sqlite3_free(pOld);
+    }
+    pWC->nSlot *= 2;
+  }
+  pTerm = &pWC->a[idx = pWC->nTerm];
+  pWC->nTerm++;
+  pTerm->pExpr = p;
+  pTerm->flags = flags;
+  pTerm->pWC = pWC;
+  pTerm->iParent = -1;
+  return idx;
+}
+
+/*
+** This routine identifies subexpressions in the WHERE clause where
+** each subexpression is separated by the AND operator or some other
+** operator specified in the op parameter.  The WhereClause structure
+** is filled with pointers to subexpressions.  For example:
+**
+**    WHERE  a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22)
+**           \________/     \_______________/     \________________/
+**            slot[0]            slot[1]               slot[2]
+**
+** The original WHERE clause in pExpr is unaltered.  All this routine
+** does is make slot[] entries point to substructure within pExpr.
+**
+** In the previous sentence and in the diagram, "slot[]" refers to
+** the WhereClause.a[] array.  This array grows as needed to contain
+** all terms of the WHERE clause.
+*/
+static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
+  if( pExpr==0 ) return;
+  if( pExpr->op!=op ){
+    whereClauseInsert(pWC, pExpr, 0);
+  }else{
+    whereSplit(pWC, pExpr->pLeft, op);
+    whereSplit(pWC, pExpr->pRight, op);
+  }
+}
+
+/*
+** Initialize an expression mask set
+*/
+#define initMaskSet(P)  memset(P, 0, sizeof(*P))
+
+/*
+** Return the bitmask for the given cursor number.  Return 0 if
+** iCursor is not in the set.
+*/
+static Bitmask getMask(ExprMaskSet *pMaskSet, int iCursor){
+  int i;
+  for(i=0; i<pMaskSet->n; i++){
+    if( pMaskSet->ix[i]==iCursor ){
+      return ((Bitmask)1)<<i;
+    }
+  }
+  return 0;
+}
+
+/*
+** Create a new mask for cursor iCursor.
+**
+** There is one cursor per table in the FROM clause.  The number of
+** tables in the FROM clause is limited by a test early in the
+** sqlite3WhereBegin() routine.  So we know that the pMaskSet->ix[]
+** array will never overflow.
+*/
+static void createMask(ExprMaskSet *pMaskSet, int iCursor){
+  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
+  pMaskSet->ix[pMaskSet->n++] = iCursor;
+}
+
+/*
+** This routine walks (recursively) an expression tree and generates
+** a bitmask indicating which tables are used in that expression
+** tree.
+**
+** In order for this routine to work, the calling function must have
+** previously invoked sqlite3ExprResolveNames() on the expression.  See
+** the header comment on that routine for additional information.
+** The sqlite3ExprResolveNames() routines looks for column names and
+** sets their opcodes to TK_COLUMN and their Expr.iTable fields to
+** the VDBE cursor number of the table.  This routine just has to
+** translate the cursor numbers into bitmask values and OR all
+** the bitmasks together.
+*/
+static Bitmask exprListTableUsage(ExprMaskSet*, ExprList*);
+static Bitmask exprSelectTableUsage(ExprMaskSet*, Select*);
+static Bitmask exprTableUsage(ExprMaskSet *pMaskSet, Expr *p){
+  Bitmask mask = 0;
+  if( p==0 ) return 0;
+  if( p->op==TK_COLUMN ){
+    mask = getMask(pMaskSet, p->iTable);
+    return mask;
+  }
+  mask = exprTableUsage(pMaskSet, p->pRight);
+  mask |= exprTableUsage(pMaskSet, p->pLeft);
+  mask |= exprListTableUsage(pMaskSet, p->pList);
+  mask |= exprSelectTableUsage(pMaskSet, p->pSelect);
+  return mask;
+}
+static Bitmask exprListTableUsage(ExprMaskSet *pMaskSet, ExprList *pList){
+  int i;
+  Bitmask mask = 0;
+  if( pList ){
+    for(i=0; i<pList->nExpr; i++){
+      mask |= exprTableUsage(pMaskSet, pList->a[i].pExpr);
+    }
+  }
+  return mask;
+}
+static Bitmask exprSelectTableUsage(ExprMaskSet *pMaskSet, Select *pS){
+  Bitmask mask = 0;
+  while( pS ){
+    mask |= exprListTableUsage(pMaskSet, pS->pEList);
+    mask |= exprListTableUsage(pMaskSet, pS->pGroupBy);
+    mask |= exprListTableUsage(pMaskSet, pS->pOrderBy);
+    mask |= exprTableUsage(pMaskSet, pS->pWhere);
+    mask |= exprTableUsage(pMaskSet, pS->pHaving);
+    pS = pS->pPrior;
+  }
+  return mask;
+}
+
+/*
+** Return TRUE if the given operator is one of the operators that is
+** allowed for an indexable WHERE clause term.  The allowed operators are
+** "=", "<", ">", "<=", ">=", and "IN".
+*/
+static int allowedOp(int op){
+  assert( TK_GT>TK_EQ && TK_GT<TK_GE );
+  assert( TK_LT>TK_EQ && TK_LT<TK_GE );
+  assert( TK_LE>TK_EQ && TK_LE<TK_GE );
+  assert( TK_GE==TK_EQ+4 );
+  return op==TK_IN || (op>=TK_EQ && op<=TK_GE) || op==TK_ISNULL;
+}
+
+/*
+** Swap two objects of type T.
+*/
+#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
+
+/*
+** Commute a comparision operator.  Expressions of the form "X op Y"
+** are converted into "Y op X".
+**
+** If a collation sequence is associated with either the left or right
+** side of the comparison, it remains associated with the same side after
+** the commutation. So "Y collate NOCASE op X" becomes 
+** "X collate NOCASE op Y". This is because any collation sequence on
+** the left hand side of a comparison overrides any collation sequence 
+** attached to the right. For the same reason the EP_ExpCollate flag
+** is not commuted.
+*/
+static void exprCommute(Expr *pExpr){
+  u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
+  u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
+  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
+  SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);
+  pExpr->pRight->flags = (pExpr->pRight->flags & ~EP_ExpCollate) | expLeft;
+  pExpr->pLeft->flags = (pExpr->pLeft->flags & ~EP_ExpCollate) | expRight;
+  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
+  if( pExpr->op>=TK_GT ){
+    assert( TK_LT==TK_GT+2 );
+    assert( TK_GE==TK_LE+2 );
+    assert( TK_GT>TK_EQ );
+    assert( TK_GT<TK_LE );
+    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
+    pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
+  }
+}
+
+/*
+** Translate from TK_xx operator to WO_xx bitmask.
+*/
+static int operatorMask(int op){
+  int c;
+  assert( allowedOp(op) );
+  if( op==TK_IN ){
+    c = WO_IN;
+  }else if( op==TK_ISNULL ){
+    c = WO_ISNULL;
+  }else{
+    c = WO_EQ<<(op-TK_EQ);
+  }
+  assert( op!=TK_ISNULL || c==WO_ISNULL );
+  assert( op!=TK_IN || c==WO_IN );
+  assert( op!=TK_EQ || c==WO_EQ );
+  assert( op!=TK_LT || c==WO_LT );
+  assert( op!=TK_LE || c==WO_LE );
+  assert( op!=TK_GT || c==WO_GT );
+  assert( op!=TK_GE || c==WO_GE );
+  return c;
+}
+
+/*
+** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
+** where X is a reference to the iColumn of table iCur and <op> is one of
+** the WO_xx operator codes specified by the op parameter.
+** Return a pointer to the term.  Return 0 if not found.
+*/
+static WhereTerm *findTerm(
+  WhereClause *pWC,     /* The WHERE clause to be searched */
+  int iCur,             /* Cursor number of LHS */
+  int iColumn,          /* Column number of LHS */
+  Bitmask notReady,     /* RHS must not overlap with this mask */
+  u16 op,               /* Mask of WO_xx values describing operator */
+  Index *pIdx           /* Must be compatible with this index, if not NULL */
+){
+  WhereTerm *pTerm;
+  int k;
+  for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
+    if( pTerm->leftCursor==iCur
+       && (pTerm->prereqRight & notReady)==0
+       && pTerm->leftColumn==iColumn
+       && (pTerm->eOperator & op)!=0
+    ){
+      if( iCur>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){
+        Expr *pX = pTerm->pExpr;
+        CollSeq *pColl;
+        char idxaff;
+        int j;
+        Parse *pParse = pWC->pParse;
+
+        idxaff = pIdx->pTable->aCol[iColumn].affinity;
+        if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
+
+        /* Figure out the collation sequence required from an index for
+        ** it to be useful for optimising expression pX. Store this
+        ** value in variable pColl.
+        */
+        assert(pX->pLeft);
+        pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
+        if( !pColl ){
+          pColl = pParse->db->pDfltColl;
+        }
+
+        for(j=0; j<pIdx->nColumn && pIdx->aiColumn[j]!=iColumn; j++){}
+        assert( j<pIdx->nColumn );
+        if( sqlite3StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;
+      }
+      return pTerm;
+    }
+  }
+  return 0;
+}
+
+/* Forward reference */
+static void exprAnalyze(SrcList*, WhereClause*, int);
+
+/*
+** Call exprAnalyze on all terms in a WHERE clause.  
+**
+**
+*/
+static void exprAnalyzeAll(
+  SrcList *pTabList,       /* the FROM clause */
+  WhereClause *pWC         /* the WHERE clause to be analyzed */
+){
+  int i;
+  for(i=pWC->nTerm-1; i>=0; i--){
+    exprAnalyze(pTabList, pWC, i);
+  }
+}
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+/*
+** Check to see if the given expression is a LIKE or GLOB operator that
+** can be optimized using inequality constraints.  Return TRUE if it is
+** so and false if not.
+**
+** In order for the operator to be optimizible, the RHS must be a string
+** literal that does not begin with a wildcard.  
+*/
+static int isLikeOrGlob(
+  sqlite3 *db,      /* The database */
+  Expr *pExpr,      /* Test this expression */
+  int *pnPattern,   /* Number of non-wildcard prefix characters */
+  int *pisComplete, /* True if the only wildcard is % in the last character */
+  int *pnoCase      /* True if uppercase is equivalent to lowercase */
+){
+  const char *z;
+  Expr *pRight, *pLeft;
+  ExprList *pList;
+  int c, cnt;
+  char wc[3];
+  CollSeq *pColl;
+
+  if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){
+    return 0;
+  }
+#ifdef SQLITE_EBCDIC
+  if( *pnoCase ) return 0;
+#endif
+  pList = pExpr->pList;
+  pRight = pList->a[0].pExpr;
+  if( pRight->op!=TK_STRING
+   && (pRight->op!=TK_REGISTER || pRight->iColumn!=TK_STRING) ){
+    return 0;
+  }
+  pLeft = pList->a[1].pExpr;
+  if( pLeft->op!=TK_COLUMN ){
+    return 0;
+  }
+  pColl = pLeft->pColl;
+  assert( pColl!=0 || pLeft->iColumn==-1 );
+  if( pColl==0 ){
+    /* No collation is defined for the ROWID.  Use the default. */
+    pColl = db->pDfltColl;
+  }
+  if( (pColl->type!=SQLITE_COLL_BINARY || *pnoCase) &&
+      (pColl->type!=SQLITE_COLL_NOCASE || !*pnoCase) ){
+    return 0;
+  }
+  sqlite3DequoteExpr(db, pRight);
+  z = (char *)pRight->token.z;
+  cnt = 0;
+  if( z ){
+    while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){ cnt++; }
+  }
+  if( cnt==0 || 255==(u8)z[cnt] ){
+    return 0;
+  }
+  *pisComplete = z[cnt]==wc[0] && z[cnt+1]==0;
+  *pnPattern = cnt;
+  return 1;
+}
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Check to see if the given expression is of the form
+**
+**         column MATCH expr
+**
+** If it is then return TRUE.  If not, return FALSE.
+*/
+static int isMatchOfColumn(
+  Expr *pExpr      /* Test this expression */
+){
+  ExprList *pList;
+
+  if( pExpr->op!=TK_FUNCTION ){
+    return 0;
+  }
+  if( pExpr->token.n!=5 ||
+       sqlite3StrNICmp((const char*)pExpr->token.z,"match",5)!=0 ){
+    return 0;
+  }
+  pList = pExpr->pList;
+  if( pList->nExpr!=2 ){
+    return 0;
+  }
+  if( pList->a[1].pExpr->op != TK_COLUMN ){
+    return 0;
+  }
+  return 1;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** If the pBase expression originated in the ON or USING clause of
+** a join, then transfer the appropriate markings over to derived.
+*/
+static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
+  pDerived->flags |= pBase->flags & EP_FromJoin;
+  pDerived->iRightJoinTable = pBase->iRightJoinTable;
+}
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Return TRUE if the given term of an OR clause can be converted
+** into an IN clause.  The iCursor and iColumn define the left-hand
+** side of the IN clause.
+**
+** The context is that we have multiple OR-connected equality terms
+** like this:
+**
+**           a=<expr1> OR  a=<expr2> OR b=<expr3>  OR ...
+**
+** The pOrTerm input to this routine corresponds to a single term of
+** this OR clause.  In order for the term to be a condidate for
+** conversion to an IN operator, the following must be true:
+**
+**     *  The left-hand side of the term must be the column which
+**        is identified by iCursor and iColumn.
+**
+**     *  If the right-hand side is also a column, then the affinities
+**        of both right and left sides must be such that no type
+**        conversions are required on the right.  (Ticket #2249)
+**
+** If both of these conditions are true, then return true.  Otherwise
+** return false.
+*/
+static int orTermIsOptCandidate(WhereTerm *pOrTerm, int iCursor, int iColumn){
+  int affLeft, affRight;
+  assert( pOrTerm->eOperator==WO_EQ );
+  if( pOrTerm->leftCursor!=iCursor ){
+    return 0;
+  }
+  if( pOrTerm->leftColumn!=iColumn ){
+    return 0;
+  }
+  affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
+  if( affRight==0 ){
+    return 1;
+  }
+  affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
+  if( affRight!=affLeft ){
+    return 0;
+  }
+  return 1;
+}
+
+/*
+** Return true if the given term of an OR clause can be ignored during
+** a check to make sure all OR terms are candidates for optimization.
+** In other words, return true if a call to the orTermIsOptCandidate()
+** above returned false but it is not necessary to disqualify the
+** optimization.
+**
+** Suppose the original OR phrase was this:
+**
+**           a=4  OR  a=11  OR  a=b
+**
+** During analysis, the third term gets flipped around and duplicate
+** so that we are left with this:
+**
+**           a=4  OR  a=11  OR  a=b  OR  b=a
+**
+** Since the last two terms are duplicates, only one of them
+** has to qualify in order for the whole phrase to qualify.  When
+** this routine is called, we know that pOrTerm did not qualify.
+** This routine merely checks to see if pOrTerm has a duplicate that
+** might qualify.  If there is a duplicate that has not yet been
+** disqualified, then return true.  If there are no duplicates, or
+** the duplicate has also been disqualifed, return false.
+*/
+static int orTermHasOkDuplicate(WhereClause *pOr, WhereTerm *pOrTerm){
+  if( pOrTerm->flags & TERM_COPIED ){
+    /* This is the original term.  The duplicate is to the left had
+    ** has not yet been analyzed and thus has not yet been disqualified. */
+    return 1;
+  }
+  if( (pOrTerm->flags & TERM_VIRTUAL)!=0
+     && (pOr->a[pOrTerm->iParent].flags & TERM_OR_OK)!=0 ){
+    /* This is a duplicate term.  The original qualified so this one
+    ** does not have to. */
+    return 1;
+  }
+  /* This is either a singleton term or else it is a duplicate for
+  ** which the original did not qualify.  Either way we are done for. */
+  return 0;
+}
+#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */
+
+/*
+** The input to this routine is an WhereTerm structure with only the
+** "pExpr" field filled in.  The job of this routine is to analyze the
+** subexpression and populate all the other fields of the WhereTerm
+** structure.
+**
+** If the expression is of the form "<expr> <op> X" it gets commuted
+** to the standard form of "X <op> <expr>".  If the expression is of
+** the form "X <op> Y" where both X and Y are columns, then the original
+** expression is unchanged and a new virtual expression of the form
+** "Y <op> X" is added to the WHERE clause and analyzed separately.
+*/
+static void exprAnalyze(
+  SrcList *pSrc,            /* the FROM clause */
+  WhereClause *pWC,         /* the WHERE clause */
+  int idxTerm               /* Index of the term to be analyzed */
+){
+  WhereTerm *pTerm;
+  ExprMaskSet *pMaskSet;
+  Expr *pExpr;
+  Bitmask prereqLeft;
+  Bitmask prereqAll;
+  Bitmask extraRight = 0;
+  int nPattern;
+  int isComplete;
+  int noCase;
+  int op;
+  Parse *pParse = pWC->pParse;
+  sqlite3 *db = pParse->db;
+
+  if( db->mallocFailed ){
+    return;
+  }
+  pTerm = &pWC->a[idxTerm];
+  pMaskSet = pWC->pMaskSet;
+  pExpr = pTerm->pExpr;
+  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
+  op = pExpr->op;
+  if( op==TK_IN ){
+    assert( pExpr->pRight==0 );
+    pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->pList)
+                          | exprSelectTableUsage(pMaskSet, pExpr->pSelect);
+  }else if( op==TK_ISNULL ){
+    pTerm->prereqRight = 0;
+  }else{
+    pTerm->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
+  }
+  prereqAll = exprTableUsage(pMaskSet, pExpr);
+  if( ExprHasProperty(pExpr, EP_FromJoin) ){
+    Bitmask x = getMask(pMaskSet, pExpr->iRightJoinTable);
+    prereqAll |= x;
+    extraRight = x-1;  /* ON clause terms may not be used with an index
+                       ** on left table of a LEFT JOIN.  Ticket #3015 */
+  }
+  pTerm->prereqAll = prereqAll;
+  pTerm->leftCursor = -1;
+  pTerm->iParent = -1;
+  pTerm->eOperator = 0;
+  if( allowedOp(op) && (pTerm->prereqRight & prereqLeft)==0 ){
+    Expr *pLeft = pExpr->pLeft;
+    Expr *pRight = pExpr->pRight;
+    if( pLeft->op==TK_COLUMN ){
+      pTerm->leftCursor = pLeft->iTable;
+      pTerm->leftColumn = pLeft->iColumn;
+      pTerm->eOperator = operatorMask(op);
+    }
+    if( pRight && pRight->op==TK_COLUMN ){
+      WhereTerm *pNew;
+      Expr *pDup;
+      if( pTerm->leftCursor>=0 ){
+        int idxNew;
+        pDup = sqlite3ExprDup(db, pExpr);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(pDup);
+          return;
+        }
+        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
+        if( idxNew==0 ) return;
+        pNew = &pWC->a[idxNew];
+        pNew->iParent = idxTerm;
+        pTerm = &pWC->a[idxTerm];
+        pTerm->nChild = 1;
+        pTerm->flags |= TERM_COPIED;
+      }else{
+        pDup = pExpr;
+        pNew = pTerm;
+      }
+      exprCommute(pDup);
+      pLeft = pDup->pLeft;
+      pNew->leftCursor = pLeft->iTable;
+      pNew->leftColumn = pLeft->iColumn;
+      pNew->prereqRight = prereqLeft;
+      pNew->prereqAll = prereqAll;
+      pNew->eOperator = operatorMask(pDup->op);
+    }
+  }
+
+#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  /* If a term is the BETWEEN operator, create two new virtual terms
+  ** that define the range that the BETWEEN implements.
+  */
+  else if( pExpr->op==TK_BETWEEN ){
+    ExprList *pList = pExpr->pList;
+    int i;
+    static const u8 ops[] = {TK_GE, TK_LE};
+    assert( pList!=0 );
+    assert( pList->nExpr==2 );
+    for(i=0; i<2; i++){
+      Expr *pNewExpr;
+      int idxNew;
+      pNewExpr = sqlite3Expr(db, ops[i], sqlite3ExprDup(db, pExpr->pLeft),
+                             sqlite3ExprDup(db, pList->a[i].pExpr), 0);
+      idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+      exprAnalyze(pSrc, pWC, idxNew);
+      pTerm = &pWC->a[idxTerm];
+      pWC->a[idxNew].iParent = idxTerm;
+    }
+    pTerm->nChild = 2;
+  }
+#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+  /* Attempt to convert OR-connected terms into an IN operator so that
+  ** they can make use of indices.  Example:
+  **
+  **      x = expr1  OR  expr2 = x  OR  x = expr3
+  **
+  ** is converted into
+  **
+  **      x IN (expr1,expr2,expr3)
+  **
+  ** This optimization must be omitted if OMIT_SUBQUERY is defined because
+  ** the compiler for the the IN operator is part of sub-queries.
+  */
+  else if( pExpr->op==TK_OR ){
+    int ok;
+    int i, j;
+    int iColumn, iCursor;
+    WhereClause sOr;
+    WhereTerm *pOrTerm;
+
+    assert( (pTerm->flags & TERM_DYNAMIC)==0 );
+    whereClauseInit(&sOr, pWC->pParse, pMaskSet);
+    whereSplit(&sOr, pExpr, TK_OR);
+    exprAnalyzeAll(pSrc, &sOr);
+    assert( sOr.nTerm>=2 );
+    j = 0;
+    if( db->mallocFailed ) goto or_not_possible;
+    do{
+      assert( j<sOr.nTerm );
+      iColumn = sOr.a[j].leftColumn;
+      iCursor = sOr.a[j].leftCursor;
+      ok = iCursor>=0;
+      for(i=sOr.nTerm-1, pOrTerm=sOr.a; i>=0 && ok; i--, pOrTerm++){
+        if( pOrTerm->eOperator!=WO_EQ ){
+          goto or_not_possible;
+        }
+        if( orTermIsOptCandidate(pOrTerm, iCursor, iColumn) ){
+          pOrTerm->flags |= TERM_OR_OK;
+        }else if( orTermHasOkDuplicate(&sOr, pOrTerm) ){
+          pOrTerm->flags &= ~TERM_OR_OK;
+        }else{
+          ok = 0;
+        }
+      }
+    }while( !ok && (sOr.a[j++].flags & TERM_COPIED)!=0 && j<2 );
+    if( ok ){
+      ExprList *pList = 0;
+      Expr *pNew, *pDup;
+      Expr *pLeft = 0;
+      for(i=sOr.nTerm-1, pOrTerm=sOr.a; i>=0 && ok; i--, pOrTerm++){
+        if( (pOrTerm->flags & TERM_OR_OK)==0 ) continue;
+        pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight);
+        pList = sqlite3ExprListAppend(pWC->pParse, pList, pDup, 0);
+        pLeft = pOrTerm->pExpr->pLeft;
+      }
+      assert( pLeft!=0 );
+      pDup = sqlite3ExprDup(db, pLeft);
+      pNew = sqlite3Expr(db, TK_IN, pDup, 0, 0);
+      if( pNew ){
+        int idxNew;
+        transferJoinMarkings(pNew, pExpr);
+        pNew->pList = pList;
+        idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+        exprAnalyze(pSrc, pWC, idxNew);
+        pTerm = &pWC->a[idxTerm];
+        pWC->a[idxNew].iParent = idxTerm;
+        pTerm->nChild = 1;
+      }else{
+        sqlite3ExprListDelete(pList);
+      }
+    }
+or_not_possible:
+    whereClauseClear(&sOr);
+  }
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+  /* Add constraints to reduce the search space on a LIKE or GLOB
+  ** operator.
+  **
+  ** A like pattern of the form "x LIKE 'abc%'" is changed into constraints
+  **
+  **          x>='abc' AND x<'abd' AND x LIKE 'abc%'
+  **
+  ** The last character of the prefix "abc" is incremented to form the
+  ** termination condidtion "abd".  This trick of incrementing the last
+  ** is not 255 and if the character set is not EBCDIC.  
+  */
+  if( isLikeOrGlob(db, pExpr, &nPattern, &isComplete, &noCase) ){
+    Expr *pLeft, *pRight;
+    Expr *pStr1, *pStr2;
+    Expr *pNewExpr1, *pNewExpr2;
+    int idxNew1, idxNew2;
+
+    pLeft = pExpr->pList->a[1].pExpr;
+    pRight = pExpr->pList->a[0].pExpr;
+    pStr1 = sqlite3PExpr(pParse, TK_STRING, 0, 0, 0);
+    if( pStr1 ){
+      sqlite3TokenCopy(db, &pStr1->token, &pRight->token);
+      pStr1->token.n = nPattern;
+      pStr1->flags = EP_Dequoted;
+    }
+    pStr2 = sqlite3ExprDup(db, pStr1);
+    if( !db->mallocFailed ){
+      u8 c, *pC;
+      assert( pStr2->token.dyn );
+      pC = (u8*)&pStr2->token.z[nPattern-1];
+      c = *pC;
+      if( noCase ) c = sqlite3UpperToLower[c];
+      *pC = c + 1;
+    }
+    pNewExpr1 = sqlite3PExpr(pParse, TK_GE, sqlite3ExprDup(db,pLeft), pStr1, 0);
+    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
+    exprAnalyze(pSrc, pWC, idxNew1);
+    pNewExpr2 = sqlite3PExpr(pParse, TK_LT, sqlite3ExprDup(db,pLeft), pStr2, 0);
+    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
+    exprAnalyze(pSrc, pWC, idxNew2);
+    pTerm = &pWC->a[idxTerm];
+    if( isComplete ){
+      pWC->a[idxNew1].iParent = idxTerm;
+      pWC->a[idxNew2].iParent = idxTerm;
+      pTerm->nChild = 2;
+    }
+  }
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Add a WO_MATCH auxiliary term to the constraint set if the
+  ** current expression is of the form:  column MATCH expr.
+  ** This information is used by the xBestIndex methods of
+  ** virtual tables.  The native query optimizer does not attempt
+  ** to do anything with MATCH functions.
+  */
+  if( isMatchOfColumn(pExpr) ){
+    int idxNew;
+    Expr *pRight, *pLeft;
+    WhereTerm *pNewTerm;
+    Bitmask prereqColumn, prereqExpr;
+
+    pRight = pExpr->pList->a[0].pExpr;
+    pLeft = pExpr->pList->a[1].pExpr;
+    prereqExpr = exprTableUsage(pMaskSet, pRight);
+    prereqColumn = exprTableUsage(pMaskSet, pLeft);
+    if( (prereqExpr & prereqColumn)==0 ){
+      Expr *pNewExpr;
+      pNewExpr = sqlite3Expr(db, TK_MATCH, 0, sqlite3ExprDup(db, pRight), 0);
+      idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+      pNewTerm = &pWC->a[idxNew];
+      pNewTerm->prereqRight = prereqExpr;
+      pNewTerm->leftCursor = pLeft->iTable;
+      pNewTerm->leftColumn = pLeft->iColumn;
+      pNewTerm->eOperator = WO_MATCH;
+      pNewTerm->iParent = idxTerm;
+      pTerm = &pWC->a[idxTerm];
+      pTerm->nChild = 1;
+      pTerm->flags |= TERM_COPIED;
+      pNewTerm->prereqAll = pTerm->prereqAll;
+    }
+  }
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
+  ** an index for tables to the left of the join.
+  */
+  pTerm->prereqRight |= extraRight;
+}
+
+/*
+** Return TRUE if any of the expressions in pList->a[iFirst...] contain
+** a reference to any table other than the iBase table.
+*/
+static int referencesOtherTables(
+  ExprList *pList,          /* Search expressions in ths list */
+  ExprMaskSet *pMaskSet,    /* Mapping from tables to bitmaps */
+  int iFirst,               /* Be searching with the iFirst-th expression */
+  int iBase                 /* Ignore references to this table */
+){
+  Bitmask allowed = ~getMask(pMaskSet, iBase);
+  while( iFirst<pList->nExpr ){
+    if( (exprTableUsage(pMaskSet, pList->a[iFirst++].pExpr)&allowed)!=0 ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** This routine decides if pIdx can be used to satisfy the ORDER BY
+** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
+** ORDER BY clause, this routine returns 0.
+**
+** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
+** left-most table in the FROM clause of that same SELECT statement and
+** the table has a cursor number of "base".  pIdx is an index on pTab.
+**
+** nEqCol is the number of columns of pIdx that are used as equality
+** constraints.  Any of these columns may be missing from the ORDER BY
+** clause and the match can still be a success.
+**
+** All terms of the ORDER BY that match against the index must be either
+** ASC or DESC.  (Terms of the ORDER BY clause past the end of a UNIQUE
+** index do not need to satisfy this constraint.)  The *pbRev value is
+** set to 1 if the ORDER BY clause is all DESC and it is set to 0 if
+** the ORDER BY clause is all ASC.
+*/
+static int isSortingIndex(
+  Parse *pParse,          /* Parsing context */
+  ExprMaskSet *pMaskSet,  /* Mapping from table indices to bitmaps */
+  Index *pIdx,            /* The index we are testing */
+  int base,               /* Cursor number for the table to be sorted */
+  ExprList *pOrderBy,     /* The ORDER BY clause */
+  int nEqCol,             /* Number of index columns with == constraints */
+  int *pbRev              /* Set to 1 if ORDER BY is DESC */
+){
+  int i, j;                       /* Loop counters */
+  int sortOrder = 0;              /* XOR of index and ORDER BY sort direction */
+  int nTerm;                      /* Number of ORDER BY terms */
+  struct ExprList_item *pTerm;    /* A term of the ORDER BY clause */
+  sqlite3 *db = pParse->db;
+
+  assert( pOrderBy!=0 );
+  nTerm = pOrderBy->nExpr;
+  assert( nTerm>0 );
+
+  /* Match terms of the ORDER BY clause against columns of
+  ** the index.
+  **
+  ** Note that indices have pIdx->nColumn regular columns plus
+  ** one additional column containing the rowid.  The rowid column
+  ** of the index is also allowed to match against the ORDER BY
+  ** clause.
+  */
+  for(i=j=0, pTerm=pOrderBy->a; j<nTerm && i<=pIdx->nColumn; i++){
+    Expr *pExpr;       /* The expression of the ORDER BY pTerm */
+    CollSeq *pColl;    /* The collating sequence of pExpr */
+    int termSortOrder; /* Sort order for this term */
+    int iColumn;       /* The i-th column of the index.  -1 for rowid */
+    int iSortOrder;    /* 1 for DESC, 0 for ASC on the i-th index term */
+    const char *zColl; /* Name of the collating sequence for i-th index term */
+
+    pExpr = pTerm->pExpr;
+    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
+      /* Can not use an index sort on anything that is not a column in the
+      ** left-most table of the FROM clause */
+      break;
+    }
+    pColl = sqlite3ExprCollSeq(pParse, pExpr);
+    if( !pColl ){
+      pColl = db->pDfltColl;
+    }
+    if( i<pIdx->nColumn ){
+      iColumn = pIdx->aiColumn[i];
+      if( iColumn==pIdx->pTable->iPKey ){
+        iColumn = -1;
+      }
+      iSortOrder = pIdx->aSortOrder[i];
+      zColl = pIdx->azColl[i];
+    }else{
+      iColumn = -1;
+      iSortOrder = 0;
+      zColl = pColl->zName;
+    }
+    if( pExpr->iColumn!=iColumn || sqlite3StrICmp(pColl->zName, zColl) ){
+      /* Term j of the ORDER BY clause does not match column i of the index */
+      if( i<nEqCol ){
+        /* If an index column that is constrained by == fails to match an
+        ** ORDER BY term, that is OK.  Just ignore that column of the index
+        */
+        continue;
+      }else{
+        /* If an index column fails to match and is not constrained by ==
+        ** then the index cannot satisfy the ORDER BY constraint.
+        */
+        return 0;
+      }
+    }
+    assert( pIdx->aSortOrder!=0 );
+    assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
+    assert( iSortOrder==0 || iSortOrder==1 );
+    termSortOrder = iSortOrder ^ pTerm->sortOrder;
+    if( i>nEqCol ){
+      if( termSortOrder!=sortOrder ){
+        /* Indices can only be used if all ORDER BY terms past the
+        ** equality constraints are all either DESC or ASC. */
+        return 0;
+      }
+    }else{
+      sortOrder = termSortOrder;
+    }
+    j++;
+    pTerm++;
+    if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
+      /* If the indexed column is the primary key and everything matches
+      ** so far and none of the ORDER BY terms to the right reference other
+      ** tables in the join, then we are assured that the index can be used 
+      ** to sort because the primary key is unique and so none of the other
+      ** columns will make any difference
+      */
+      j = nTerm;
+    }
+  }
+
+  *pbRev = sortOrder!=0;
+  if( j>=nTerm ){
+    /* All terms of the ORDER BY clause are covered by this index so
+    ** this index can be used for sorting. */
+    return 1;
+  }
+  if( pIdx->onError!=OE_None && i==pIdx->nColumn
+      && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
+    /* All terms of this index match some prefix of the ORDER BY clause
+    ** and the index is UNIQUE and no terms on the tail of the ORDER BY
+    ** clause reference other tables in a join.  If this is all true then
+    ** the order by clause is superfluous. */
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Check table to see if the ORDER BY clause in pOrderBy can be satisfied
+** by sorting in order of ROWID.  Return true if so and set *pbRev to be
+** true for reverse ROWID and false for forward ROWID order.
+*/
+static int sortableByRowid(
+  int base,               /* Cursor number for table to be sorted */
+  ExprList *pOrderBy,     /* The ORDER BY clause */
+  ExprMaskSet *pMaskSet,  /* Mapping from tables to bitmaps */
+  int *pbRev              /* Set to 1 if ORDER BY is DESC */
+){
+  Expr *p;
+
+  assert( pOrderBy!=0 );
+  assert( pOrderBy->nExpr>0 );
+  p = pOrderBy->a[0].pExpr;
+  if( p->op==TK_COLUMN && p->iTable==base && p->iColumn==-1
+    && !referencesOtherTables(pOrderBy, pMaskSet, 1, base) ){
+    *pbRev = pOrderBy->a[0].sortOrder;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Prepare a crude estimate of the logarithm of the input value.
+** The results need not be exact.  This is only used for estimating
+** the total cost of performing operatings with O(logN) or O(NlogN)
+** complexity.  Because N is just a guess, it is no great tragedy if
+** logN is a little off.
+*/
+static double estLog(double N){
+  double logN = 1;
+  double x = 10;
+  while( N>x ){
+    logN += 1;
+    x *= 10;
+  }
+  return logN;
+}
+
+/*
+** Two routines for printing the content of an sqlite3_index_info
+** structure.  Used for testing and debugging only.  If neither
+** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
+** are no-ops.
+*/
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_DEBUG)
+static void TRACE_IDX_INPUTS(sqlite3_index_info *p){
+  int i;
+  if( !sqlite3WhereTrace ) return;
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
+       i,
+       p->aConstraint[i].iColumn,
+       p->aConstraint[i].iTermOffset,
+       p->aConstraint[i].op,
+       p->aConstraint[i].usable);
+  }
+  for(i=0; i<p->nOrderBy; i++){
+    sqlite3DebugPrintf("  orderby[%d]: col=%d desc=%d\n",
+       i,
+       p->aOrderBy[i].iColumn,
+       p->aOrderBy[i].desc);
+  }
+}
+static void TRACE_IDX_OUTPUTS(sqlite3_index_info *p){
+  int i;
+  if( !sqlite3WhereTrace ) return;
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf("  usage[%d]: argvIdx=%d omit=%d\n",
+       i,
+       p->aConstraintUsage[i].argvIndex,
+       p->aConstraintUsage[i].omit);
+  }
+  sqlite3DebugPrintf("  idxNum=%d\n", p->idxNum);
+  sqlite3DebugPrintf("  idxStr=%s\n", p->idxStr);
+  sqlite3DebugPrintf("  orderByConsumed=%d\n", p->orderByConsumed);
+  sqlite3DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
+}
+#else
+#define TRACE_IDX_INPUTS(A)
+#define TRACE_IDX_OUTPUTS(A)
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Compute the best index for a virtual table.
+**
+** The best index is computed by the xBestIndex method of the virtual
+** table module.  This routine is really just a wrapper that sets up
+** the sqlite3_index_info structure that is used to communicate with
+** xBestIndex.
+**
+** In a join, this routine might be called multiple times for the
+** same virtual table.  The sqlite3_index_info structure is created
+** and initialized on the first invocation and reused on all subsequent
+** invocations.  The sqlite3_index_info structure is also used when
+** code is generated to access the virtual table.  The whereInfoDelete() 
+** routine takes care of freeing the sqlite3_index_info structure after
+** everybody has finished with it.
+*/
+static double bestVirtualIndex(
+  Parse *pParse,                 /* The parsing context */
+  WhereClause *pWC,              /* The WHERE clause */
+  struct SrcList_item *pSrc,     /* The FROM clause term to search */
+  Bitmask notReady,              /* Mask of cursors that are not available */
+  ExprList *pOrderBy,            /* The order by clause */
+  int orderByUsable,             /* True if we can potential sort */
+  sqlite3_index_info **ppIdxInfo /* Index information passed to xBestIndex */
+){
+  Table *pTab = pSrc->pTab;
+  sqlite3_index_info *pIdxInfo;
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_orderby *pIdxOrderBy;
+  struct sqlite3_index_constraint_usage *pUsage;
+  WhereTerm *pTerm;
+  int i, j;
+  int nOrderBy;
+  int rc;
+
+  /* If the sqlite3_index_info structure has not been previously
+  ** allocated and initialized for this virtual table, then allocate
+  ** and initialize it now
+  */
+  pIdxInfo = *ppIdxInfo;
+  if( pIdxInfo==0 ){
+    WhereTerm *pTerm;
+    int nTerm;
+    WHERETRACE(("Recomputing index info for %s...\n", pTab->zName));
+
+    /* Count the number of possible WHERE clause constraints referring
+    ** to this virtual table */
+    for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+      if( pTerm->leftCursor != pSrc->iCursor ) continue;
+      if( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
+      testcase( pTerm->eOperator==WO_IN );
+      testcase( pTerm->eOperator==WO_ISNULL );
+      if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
+      nTerm++;
+    }
+
+    /* If the ORDER BY clause contains only columns in the current 
+    ** virtual table then allocate space for the aOrderBy part of
+    ** the sqlite3_index_info structure.
+    */
+    nOrderBy = 0;
+    if( pOrderBy ){
+      for(i=0; i<pOrderBy->nExpr; i++){
+        Expr *pExpr = pOrderBy->a[i].pExpr;
+        if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
+      }
+      if( i==pOrderBy->nExpr ){
+        nOrderBy = pOrderBy->nExpr;
+      }
+    }
+
+    /* Allocate the sqlite3_index_info structure
+    */
+    pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
+                             + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
+                             + sizeof(*pIdxOrderBy)*nOrderBy );
+    if( pIdxInfo==0 ){
+      sqlite3ErrorMsg(pParse, "out of memory");
+      return 0.0;
+    }
+    *ppIdxInfo = pIdxInfo;
+
+    /* Initialize the structure.  The sqlite3_index_info structure contains
+    ** many fields that are declared "const" to prevent xBestIndex from
+    ** changing them.  We have to do some funky casting in order to
+    ** initialize those fields.
+    */
+    pIdxCons = (struct sqlite3_index_constraint*)&pIdxInfo[1];
+    pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
+    pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
+    *(int*)&pIdxInfo->nConstraint = nTerm;
+    *(int*)&pIdxInfo->nOrderBy = nOrderBy;
+    *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
+    *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
+    *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
+                                                                     pUsage;
+
+    for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+      if( pTerm->leftCursor != pSrc->iCursor ) continue;
+      if( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
+      testcase( pTerm->eOperator==WO_IN );
+      testcase( pTerm->eOperator==WO_ISNULL );
+      if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
+      pIdxCons[j].iColumn = pTerm->leftColumn;
+      pIdxCons[j].iTermOffset = i;
+      pIdxCons[j].op = pTerm->eOperator;
+      /* The direct assignment in the previous line is possible only because
+      ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
+      ** following asserts verify this fact. */
+      assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
+      assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
+      assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
+      assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
+      assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
+      assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH );
+      assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
+      j++;
+    }
+    for(i=0; i<nOrderBy; i++){
+      Expr *pExpr = pOrderBy->a[i].pExpr;
+      pIdxOrderBy[i].iColumn = pExpr->iColumn;
+      pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
+    }
+  }
+
+  /* At this point, the sqlite3_index_info structure that pIdxInfo points
+  ** to will have been initialized, either during the current invocation or
+  ** during some prior invocation.  Now we just have to customize the
+  ** details of pIdxInfo for the current invocation and pass it to
+  ** xBestIndex.
+  */
+
+  /* The module name must be defined. Also, by this point there must
+  ** be a pointer to an sqlite3_vtab structure. Otherwise
+  ** sqlite3ViewGetColumnNames() would have picked up the error. 
+  */
+  assert( pTab->azModuleArg && pTab->azModuleArg[0] );
+  assert( pTab->pVtab );
+#if 0
+  if( pTab->pVtab==0 ){
+    sqlite3ErrorMsg(pParse, "undefined module %s for table %s",
+        pTab->azModuleArg[0], pTab->zName);
+    return 0.0;
+  }
+#endif
+
+  /* Set the aConstraint[].usable fields and initialize all 
+  ** output variables to zero.
+  **
+  ** aConstraint[].usable is true for constraints where the right-hand
+  ** side contains only references to tables to the left of the current
+  ** table.  In other words, if the constraint is of the form:
+  **
+  **           column = expr
+  **
+  ** and we are evaluating a join, then the constraint on column is 
+  ** only valid if all tables referenced in expr occur to the left
+  ** of the table containing column.
+  **
+  ** The aConstraints[] array contains entries for all constraints
+  ** on the current table.  That way we only have to compute it once
+  ** even though we might try to pick the best index multiple times.
+  ** For each attempt at picking an index, the order of tables in the
+  ** join might be different so we have to recompute the usable flag
+  ** each time.
+  */
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+  pUsage = pIdxInfo->aConstraintUsage;
+  for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
+    j = pIdxCons->iTermOffset;
+    pTerm = &pWC->a[j];
+    pIdxCons->usable =  (pTerm->prereqRight & notReady)==0;
+  }
+  memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
+  if( pIdxInfo->needToFreeIdxStr ){
+    sqlite3_free(pIdxInfo->idxStr);
+  }
+  pIdxInfo->idxStr = 0;
+  pIdxInfo->idxNum = 0;
+  pIdxInfo->needToFreeIdxStr = 0;
+  pIdxInfo->orderByConsumed = 0;
+  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / 2.0;
+  nOrderBy = pIdxInfo->nOrderBy;
+  if( pIdxInfo->nOrderBy && !orderByUsable ){
+    *(int*)&pIdxInfo->nOrderBy = 0;
+  }
+
+  (void)sqlite3SafetyOff(pParse->db);
+  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
+  TRACE_IDX_INPUTS(pIdxInfo);
+  rc = pTab->pVtab->pModule->xBestIndex(pTab->pVtab, pIdxInfo);
+  TRACE_IDX_OUTPUTS(pIdxInfo);
+  (void)sqlite3SafetyOn(pParse->db);
+
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    if( !pIdxInfo->aConstraint[i].usable && pUsage[i].argvIndex>0 ){
+      sqlite3ErrorMsg(pParse, 
+          "table %s: xBestIndex returned an invalid plan", pTab->zName);
+      return 0.0;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ){
+      pParse->db->mallocFailed = 1;
+    }else {
+      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
+    }
+  }
+  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
+
+  return pIdxInfo->estimatedCost;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** Find the best index for accessing a particular table.  Return a pointer
+** to the index, flags that describe how the index should be used, the
+** number of equality constraints, and the "cost" for this index.
+**
+** The lowest cost index wins.  The cost is an estimate of the amount of
+** CPU and disk I/O need to process the request using the selected index.
+** Factors that influence cost include:
+**
+**    *  The estimated number of rows that will be retrieved.  (The
+**       fewer the better.)
+**
+**    *  Whether or not sorting must occur.
+**
+**    *  Whether or not there must be separate lookups in the
+**       index and in the main table.
+**
+*/
+static double bestIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  struct SrcList_item *pSrc,  /* The FROM clause term to search */
+  Bitmask notReady,           /* Mask of cursors that are not available */
+  ExprList *pOrderBy,         /* The order by clause */
+  Index **ppIndex,            /* Make *ppIndex point to the best index */
+  int *pFlags,                /* Put flags describing this choice in *pFlags */
+  int *pnEq                   /* Put the number of == or IN constraints here */
+){
+  WhereTerm *pTerm;
+  Index *bestIdx = 0;         /* Index that gives the lowest cost */
+  double lowestCost;          /* The cost of using bestIdx */
+  int bestFlags = 0;          /* Flags associated with bestIdx */
+  int bestNEq = 0;            /* Best value for nEq */
+  int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
+  Index *pProbe;              /* An index we are evaluating */
+  int rev;                    /* True to scan in reverse order */
+  int flags;                  /* Flags associated with pProbe */
+  int nEq;                    /* Number of == or IN constraints */
+  int eqTermMask;             /* Mask of valid equality operators */
+  double cost;                /* Cost of using pProbe */
+
+  WHERETRACE(("bestIndex: tbl=%s notReady=%x\n", pSrc->pTab->zName, notReady));
+  lowestCost = SQLITE_BIG_DBL;
+  pProbe = pSrc->pTab->pIndex;
+
+  /* If the table has no indices and there are no terms in the where
+  ** clause that refer to the ROWID, then we will never be able to do
+  ** anything other than a full table scan on this table.  We might as
+  ** well put it first in the join order.  That way, perhaps it can be
+  ** referenced by other tables in the join.
+  */
+  if( pProbe==0 &&
+     findTerm(pWC, iCur, -1, 0, WO_EQ|WO_IN|WO_LT|WO_LE|WO_GT|WO_GE,0)==0 &&
+     (pOrderBy==0 || !sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev)) ){
+    *pFlags = 0;
+    *ppIndex = 0;
+    *pnEq = 0;
+    return 0.0;
+  }
+
+  /* Check for a rowid=EXPR or rowid IN (...) constraints
+  */
+  pTerm = findTerm(pWC, iCur, -1, notReady, WO_EQ|WO_IN, 0);
+  if( pTerm ){
+    Expr *pExpr;
+    *ppIndex = 0;
+    bestFlags = WHERE_ROWID_EQ;
+    if( pTerm->eOperator & WO_EQ ){
+      /* Rowid== is always the best pick.  Look no further.  Because only
+      ** a single row is generated, output is always in sorted order */
+      *pFlags = WHERE_ROWID_EQ | WHERE_UNIQUE;
+      *pnEq = 1;
+      WHERETRACE(("... best is rowid\n"));
+      return 0.0;
+    }else if( (pExpr = pTerm->pExpr)->pList!=0 ){
+      /* Rowid IN (LIST): cost is NlogN where N is the number of list
+      ** elements.  */
+      lowestCost = pExpr->pList->nExpr;
+      lowestCost *= estLog(lowestCost);
+    }else{
+      /* Rowid IN (SELECT): cost is NlogN where N is the number of rows
+      ** in the result of the inner select.  We have no way to estimate
+      ** that value so make a wild guess. */
+      lowestCost = 200;
+    }
+    WHERETRACE(("... rowid IN cost: %.9g\n", lowestCost));
+  }
+
+  /* Estimate the cost of a table scan.  If we do not know how many
+  ** entries are in the table, use 1 million as a guess.
+  */
+  cost = pProbe ? pProbe->aiRowEst[0] : 1000000;
+  WHERETRACE(("... table scan base cost: %.9g\n", cost));
+  flags = WHERE_ROWID_RANGE;
+
+  /* Check for constraints on a range of rowids in a table scan.
+  */
+  pTerm = findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE|WO_GT|WO_GE, 0);
+  if( pTerm ){
+    if( findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE, 0) ){
+      flags |= WHERE_TOP_LIMIT;
+      cost /= 3;  /* Guess that rowid<EXPR eliminates two-thirds or rows */
+    }
+    if( findTerm(pWC, iCur, -1, notReady, WO_GT|WO_GE, 0) ){
+      flags |= WHERE_BTM_LIMIT;
+      cost /= 3;  /* Guess that rowid>EXPR eliminates two-thirds of rows */
+    }
+    WHERETRACE(("... rowid range reduces cost to %.9g\n", cost));
+  }else{
+    flags = 0;
+  }
+
+  /* If the table scan does not satisfy the ORDER BY clause, increase
+  ** the cost by NlogN to cover the expense of sorting. */
+  if( pOrderBy ){
+    if( sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev) ){
+      flags |= WHERE_ORDERBY|WHERE_ROWID_RANGE;
+      if( rev ){
+        flags |= WHERE_REVERSE;
+      }
+    }else{
+      cost += cost*estLog(cost);
+      WHERETRACE(("... sorting increases cost to %.9g\n", cost));
+    }
+  }
+  if( cost<lowestCost ){
+    lowestCost = cost;
+    bestFlags = flags;
+  }
+
+  /* If the pSrc table is the right table of a LEFT JOIN then we may not
+  ** use an index to satisfy IS NULL constraints on that table.  This is
+  ** because columns might end up being NULL if the table does not match -
+  ** a circumstance which the index cannot help us discover.  Ticket #2177.
+  */
+  if( (pSrc->jointype & JT_LEFT)!=0 ){
+    eqTermMask = WO_EQ|WO_IN;
+  }else{
+    eqTermMask = WO_EQ|WO_IN|WO_ISNULL;
+  }
+
+  /* Look at each index.
+  */
+  for(; pProbe; pProbe=pProbe->pNext){
+    int i;                       /* Loop counter */
+    double inMultiplier = 1;
+
+    WHERETRACE(("... index %s:\n", pProbe->zName));
+
+    /* Count the number of columns in the index that are satisfied
+    ** by x=EXPR constraints or x IN (...) constraints.
+    */
+    flags = 0;
+    for(i=0; i<pProbe->nColumn; i++){
+      int j = pProbe->aiColumn[i];
+      pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pProbe);
+      if( pTerm==0 ) break;
+      flags |= WHERE_COLUMN_EQ;
+      if( pTerm->eOperator & WO_IN ){
+        Expr *pExpr = pTerm->pExpr;
+        flags |= WHERE_COLUMN_IN;
+        if( pExpr->pSelect!=0 ){
+          inMultiplier *= 25;
+        }else if( pExpr->pList!=0 ){
+          inMultiplier *= pExpr->pList->nExpr + 1;
+        }
+      }
+    }
+    cost = pProbe->aiRowEst[i] * inMultiplier * estLog(inMultiplier);
+    nEq = i;
+    if( pProbe->onError!=OE_None && (flags & WHERE_COLUMN_IN)==0
+         && nEq==pProbe->nColumn ){
+      flags |= WHERE_UNIQUE;
+    }
+    WHERETRACE(("...... nEq=%d inMult=%.9g cost=%.9g\n",nEq,inMultiplier,cost));
+
+    /* Look for range constraints
+    */
+    if( nEq<pProbe->nColumn ){
+      int j = pProbe->aiColumn[nEq];
+      pTerm = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe);
+      if( pTerm ){
+        flags |= WHERE_COLUMN_RANGE;
+        if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe) ){
+          flags |= WHERE_TOP_LIMIT;
+          cost /= 3;
+        }
+        if( findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe) ){
+          flags |= WHERE_BTM_LIMIT;
+          cost /= 3;
+        }
+        WHERETRACE(("...... range reduces cost to %.9g\n", cost));
+      }
+    }
+
+    /* Add the additional cost of sorting if that is a factor.
+    */
+    if( pOrderBy ){
+      if( (flags & WHERE_COLUMN_IN)==0 &&
+           isSortingIndex(pParse,pWC->pMaskSet,pProbe,iCur,pOrderBy,nEq,&rev) ){
+        if( flags==0 ){
+          flags = WHERE_COLUMN_RANGE;
+        }
+        flags |= WHERE_ORDERBY;
+        if( rev ){
+          flags |= WHERE_REVERSE;
+        }
+      }else{
+        cost += cost*estLog(cost);
+        WHERETRACE(("...... orderby increases cost to %.9g\n", cost));
+      }
+    }
+
+    /* Check to see if we can get away with using just the index without
+    ** ever reading the table.  If that is the case, then halve the
+    ** cost of this index.
+    */
+    if( flags && pSrc->colUsed < (((Bitmask)1)<<(BMS-1)) ){
+      Bitmask m = pSrc->colUsed;
+      int j;
+      for(j=0; j<pProbe->nColumn; j++){
+        int x = pProbe->aiColumn[j];
+        if( x<BMS-1 ){
+          m &= ~(((Bitmask)1)<<x);
+        }
+      }
+      if( m==0 ){
+        flags |= WHERE_IDX_ONLY;
+        cost /= 2;
+        WHERETRACE(("...... idx-only reduces cost to %.9g\n", cost));
+      }
+    }
+
+    /* If this index has achieved the lowest cost so far, then use it.
+    */
+    if( flags && cost < lowestCost ){
+      bestIdx = pProbe;
+      lowestCost = cost;
+      bestFlags = flags;
+      bestNEq = nEq;
+    }
+  }
+
+  /* Report the best result
+  */
+  *ppIndex = bestIdx;
+  WHERETRACE(("best index is %s, cost=%.9g, flags=%x, nEq=%d\n",
+        bestIdx ? bestIdx->zName : "(none)", lowestCost, bestFlags, bestNEq));
+  *pFlags = bestFlags | eqTermMask;
+  *pnEq = bestNEq;
+  return lowestCost;
+}
+
+
+/*
+** Disable a term in the WHERE clause.  Except, do not disable the term
+** if it controls a LEFT OUTER JOIN and it did not originate in the ON
+** or USING clause of that join.
+**
+** Consider the term t2.z='ok' in the following queries:
+**
+**   (1)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok'
+**   (2)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok'
+**   (3)  SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok'
+**
+** The t2.z='ok' is disabled in the in (2) because it originates
+** in the ON clause.  The term is disabled in (3) because it is not part
+** of a LEFT OUTER JOIN.  In (1), the term is not disabled.
+**
+** Disabling a term causes that term to not be tested in the inner loop
+** of the join.  Disabling is an optimization.  When terms are satisfied
+** by indices, we disable them to prevent redundant tests in the inner
+** loop.  We would get the correct results if nothing were ever disabled,
+** but joins might run a little slower.  The trick is to disable as much
+** as we can without disabling too much.  If we disabled in (1), we'd get
+** the wrong answer.  See ticket #813.
+*/
+static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
+  if( pTerm
+      && (pTerm->flags & TERM_CODED)==0
+      && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin))
+  ){
+    pTerm->flags |= TERM_CODED;
+    if( pTerm->iParent>=0 ){
+      WhereTerm *pOther = &pTerm->pWC->a[pTerm->iParent];
+      if( (--pOther->nChild)==0 ){
+        disableTerm(pLevel, pOther);
+      }
+    }
+  }
+}
+
+/*
+** Apply the affinities associated with the first n columns of index
+** pIdx to the values in the n registers starting at base.
+*/
+static void codeApplyAffinity(Parse *pParse, int base, int n, Index *pIdx){
+  if( n>0 ){
+    Vdbe *v = pParse->pVdbe;
+    assert( v!=0 );
+    sqlite3VdbeAddOp2(v, OP_Affinity, base, n);
+    sqlite3IndexAffinityStr(v, pIdx);
+    sqlite3ExprCacheAffinityChange(pParse, base, n);
+  }
+}
+
+
+/*
+** Generate code for a single equality term of the WHERE clause.  An equality
+** term can be either X=expr or X IN (...).   pTerm is the term to be 
+** coded.
+**
+** The current value for the constraint is left in register iReg.
+**
+** For a constraint of the form X=expr, the expression is evaluated and its
+** result is left on the stack.  For constraints of the form X IN (...)
+** this routine sets up a loop that will iterate over all values of X.
+*/
+static int codeEqualityTerm(
+  Parse *pParse,      /* The parsing context */
+  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
+  WhereLevel *pLevel, /* When level of the FROM clause we are working on */
+  int iTarget         /* Attempt to leave results in this register */
+){
+  Expr *pX = pTerm->pExpr;
+  Vdbe *v = pParse->pVdbe;
+  int iReg;                  /* Register holding results */
+
+  if( iTarget<=0 ){
+    iReg = iTarget = sqlite3GetTempReg(pParse);
+  }
+  if( pX->op==TK_EQ ){
+    iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
+  }else if( pX->op==TK_ISNULL ){
+    iReg = iTarget;
+    sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
+#ifndef SQLITE_OMIT_SUBQUERY
+  }else{
+    int eType;
+    int iTab;
+    struct InLoop *pIn;
+
+    assert( pX->op==TK_IN );
+    iReg = iTarget;
+    eType = sqlite3FindInIndex(pParse, pX, 1);
+    iTab = pX->iTable;
+    sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
+    VdbeComment((v, "%.*s", pX->span.n, pX->span.z));
+    if( pLevel->nIn==0 ){
+      pLevel->nxt = sqlite3VdbeMakeLabel(v);
+    }
+    pLevel->nIn++;
+    pLevel->aInLoop = sqlite3DbReallocOrFree(pParse->db, pLevel->aInLoop,
+                                    sizeof(pLevel->aInLoop[0])*pLevel->nIn);
+    pIn = pLevel->aInLoop;
+    if( pIn ){
+      pIn += pLevel->nIn - 1;
+      pIn->iCur = iTab;
+      if( eType==IN_INDEX_ROWID ){
+        pIn->topAddr = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iReg);
+      }else{
+        pIn->topAddr = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
+      }
+      sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
+    }else{
+      pLevel->nIn = 0;
+    }
+#endif
+  }
+  disableTerm(pLevel, pTerm);
+  return iReg;
+}
+
+/*
+** Generate code that will evaluate all == and IN constraints for an
+** index.  The values for all constraints are left on the stack.
+**
+** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c).
+** Suppose the WHERE clause is this:  a==5 AND b IN (1,2,3) AND c>5 AND c<10
+** The index has as many as three equality constraints, but in this
+** example, the third "c" value is an inequality.  So only two 
+** constraints are coded.  This routine will generate code to evaluate
+** a==5 and b IN (1,2,3).  The current values for a and b will be left
+** on the stack - a is the deepest and b the shallowest.
+**
+** In the example above nEq==2.  But this subroutine works for any value
+** of nEq including 0.  If nEq==0, this routine is nearly a no-op.
+** The only thing it does is allocate the pLevel->iMem memory cell.
+**
+** This routine always allocates at least one memory cell and puts
+** the address of that memory cell in pLevel->iMem.  The code that
+** calls this routine will use pLevel->iMem to store the termination
+** key value of the loop.  If one or more IN operators appear, then
+** this routine allocates an additional nEq memory cells for internal
+** use.
+*/
+static int codeAllEqualityTerms(
+  Parse *pParse,        /* Parsing context */
+  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
+  WhereClause *pWC,     /* The WHERE clause */
+  Bitmask notReady,     /* Which parts of FROM have not yet been coded */
+  int nExtraReg         /* Number of extra registers to allocate */
+){
+  int nEq = pLevel->nEq;        /* The number of == or IN constraints to code */
+  Vdbe *v = pParse->pVdbe;      /* The virtual machine under construction */
+  Index *pIdx = pLevel->pIdx;   /* The index being used for this loop */
+  int iCur = pLevel->iTabCur;   /* The cursor of the table */
+  WhereTerm *pTerm;             /* A single constraint term */
+  int j;                        /* Loop counter */
+  int regBase;                  /* Base register */
+
+  /* Figure out how many memory cells we will need then allocate them.
+  ** We always need at least one used to store the loop terminator
+  ** value.  If there are IN operators we'll need one for each == or
+  ** IN constraint.
+  */
+  pLevel->iMem = pParse->nMem + 1;
+  regBase = pParse->nMem + 2;
+  pParse->nMem += pLevel->nEq + 2 + nExtraReg;
+
+  /* Evaluate the equality constraints
+  */
+  assert( pIdx->nColumn>=nEq );
+  for(j=0; j<nEq; j++){
+    int r1;
+    int k = pIdx->aiColumn[j];
+    pTerm = findTerm(pWC, iCur, k, notReady, pLevel->flags, pIdx);
+    if( pTerm==0 ) break;
+    assert( (pTerm->flags & TERM_CODED)==0 );
+    r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
+    if( r1!=regBase+j ){
+      sqlite3VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
+    }
+    testcase( pTerm->eOperator & WO_ISNULL );
+    testcase( pTerm->eOperator & WO_IN );
+    if( (pTerm->eOperator & (WO_ISNULL|WO_IN))==0 ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->brk);
+    }
+  }
+  return regBase;
+}
+
+#if defined(SQLITE_TEST)
+/*
+** The following variable holds a text description of query plan generated
+** by the most recent call to sqlite3WhereBegin().  Each call to WhereBegin
+** overwrites the previous.  This information is used for testing and
+** analysis only.
+*/
+SQLITE_API char sqlite3_query_plan[BMS*2*40];  /* Text of the join */
+static int nQPlan = 0;              /* Next free slow in _query_plan[] */
+
+#endif /* SQLITE_TEST */
+
+
+/*
+** Free a WhereInfo structure
+*/
+static void whereInfoFree(WhereInfo *pWInfo){
+  if( pWInfo ){
+    int i;
+    for(i=0; i<pWInfo->nLevel; i++){
+      sqlite3_index_info *pInfo = pWInfo->a[i].pIdxInfo;
+      if( pInfo ){
+        assert( pInfo->needToFreeIdxStr==0 );
+        sqlite3_free(pInfo);
+      }
+    }
+    sqlite3_free(pWInfo);
+  }
+}
+
+
+/*
+** Generate the beginning of the loop used for WHERE clause processing.
+** The return value is a pointer to an opaque structure that contains
+** information needed to terminate the loop.  Later, the calling routine
+** should invoke sqlite3WhereEnd() with the return value of this function
+** in order to complete the WHERE clause processing.
+**
+** If an error occurs, this routine returns NULL.
+**
+** The basic idea is to do a nested loop, one loop for each table in
+** the FROM clause of a select.  (INSERT and UPDATE statements are the
+** same as a SELECT with only a single table in the FROM clause.)  For
+** example, if the SQL is this:
+**
+**       SELECT * FROM t1, t2, t3 WHERE ...;
+**
+** Then the code generated is conceptually like the following:
+**
+**      foreach row1 in t1 do       \    Code generated
+**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
+**          foreach row3 in t3 do   /
+**            ...
+**          end                     \    Code generated
+**        end                        |-- by sqlite3WhereEnd()
+**      end                         /
+**
+** Note that the loops might not be nested in the order in which they
+** appear in the FROM clause if a different order is better able to make
+** use of indices.  Note also that when the IN operator appears in
+** the WHERE clause, it might result in additional nested loops for
+** scanning through all values on the right-hand side of the IN.
+**
+** There are Btree cursors associated with each table.  t1 uses cursor
+** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
+** And so forth.  This routine generates code to open those VDBE cursors
+** and sqlite3WhereEnd() generates the code to close them.
+**
+** The code that sqlite3WhereBegin() generates leaves the cursors named
+** in pTabList pointing at their appropriate entries.  The [...] code
+** can use OP_Column and OP_Rowid opcodes on these cursors to extract
+** data from the various tables of the loop.
+**
+** If the WHERE clause is empty, the foreach loops must each scan their
+** entire tables.  Thus a three-way join is an O(N^3) operation.  But if
+** the tables have indices and there are terms in the WHERE clause that
+** refer to those indices, a complete table scan can be avoided and the
+** code will run much faster.  Most of the work of this routine is checking
+** to see if there are indices that can be used to speed up the loop.
+**
+** Terms of the WHERE clause are also used to limit which rows actually
+** make it to the "..." in the middle of the loop.  After each "foreach",
+** terms of the WHERE clause that use only terms in that loop and outer
+** loops are evaluated and if false a jump is made around all subsequent
+** inner loops (or around the "..." if the test occurs within the inner-
+** most loop)
+**
+** OUTER JOINS
+**
+** An outer join of tables t1 and t2 is conceptally coded as follows:
+**
+**    foreach row1 in t1 do
+**      flag = 0
+**      foreach row2 in t2 do
+**        start:
+**          ...
+**          flag = 1
+**      end
+**      if flag==0 then
+**        move the row2 cursor to a null row
+**        goto start
+**      fi
+**    end
+**
+** ORDER BY CLAUSE PROCESSING
+**
+** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,
+** if there is one.  If there is no ORDER BY clause or if this routine
+** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
+**
+** If an index can be used so that the natural output order of the table
+** scan is correct for the ORDER BY clause, then that index is used and
+** *ppOrderBy is set to NULL.  This is an optimization that prevents an
+** unnecessary sort of the result set if an index appropriate for the
+** ORDER BY clause already exists.
+**
+** If the where clause loops cannot be arranged to provide the correct
+** output order, then the *ppOrderBy is unchanged.
+*/
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
+  Parse *pParse,        /* The parser context */
+  SrcList *pTabList,    /* A list of all tables to be scanned */
+  Expr *pWhere,         /* The WHERE clause */
+  ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
+  u8 wflags             /* One of the WHERE_* flags defined in sqliteInt.h */
+){
+  int i;                     /* Loop counter */
+  WhereInfo *pWInfo;         /* Will become the return value of this function */
+  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
+  int brk, cont = 0;         /* Addresses used during code generation */
+  Bitmask notReady;          /* Cursors that are not yet positioned */
+  WhereTerm *pTerm;          /* A single term in the WHERE clause */
+  ExprMaskSet maskSet;       /* The expression mask set */
+  WhereClause wc;            /* The WHERE clause is divided into these terms */
+  struct SrcList_item *pTabItem;  /* A single entry from pTabList */
+  WhereLevel *pLevel;             /* A single level in the pWInfo list */
+  int iFrom;                      /* First unused FROM clause element */
+  int andFlags;              /* AND-ed combination of all wc.a[].flags */
+  sqlite3 *db;               /* Database connection */
+  ExprList *pOrderBy = 0;
+
+  /* The number of tables in the FROM clause is limited by the number of
+  ** bits in a Bitmask 
+  */
+  if( pTabList->nSrc>BMS ){
+    sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
+    return 0;
+  }
+
+  if( ppOrderBy ){
+    pOrderBy = *ppOrderBy;
+  }
+
+  /* Split the WHERE clause into separate subexpressions where each
+  ** subexpression is separated by an AND operator.
+  */
+  initMaskSet(&maskSet);
+  whereClauseInit(&wc, pParse, &maskSet);
+  sqlite3ExprCodeConstants(pParse, pWhere);
+  whereSplit(&wc, pWhere, TK_AND);
+    
+  /* Allocate and initialize the WhereInfo structure that will become the
+  ** return value.
+  */
+  db = pParse->db;
+  pWInfo = sqlite3DbMallocZero(db,  
+                      sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
+  if( db->mallocFailed ){
+    goto whereBeginNoMem;
+  }
+  pWInfo->nLevel = pTabList->nSrc;
+  pWInfo->pParse = pParse;
+  pWInfo->pTabList = pTabList;
+  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
+
+  /* Special case: a WHERE clause that is constant.  Evaluate the
+  ** expression and either jump over all of the code or fall thru.
+  */
+  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
+    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE_JUMPIFNULL);
+    pWhere = 0;
+  }
+
+  /* Assign a bit from the bitmask to every term in the FROM clause.
+  **
+  ** When assigning bitmask values to FROM clause cursors, it must be
+  ** the case that if X is the bitmask for the N-th FROM clause term then
+  ** the bitmask for all FROM clause terms to the left of the N-th term
+  ** is (X-1).   An expression from the ON clause of a LEFT JOIN can use
+  ** its Expr.iRightJoinTable value to find the bitmask of the right table
+  ** of the join.  Subtracting one from the right table bitmask gives a
+  ** bitmask for all tables to the left of the join.  Knowing the bitmask
+  ** for all tables to the left of a left join is important.  Ticket #3015.
+  */
+  for(i=0; i<pTabList->nSrc; i++){
+    createMask(&maskSet, pTabList->a[i].iCursor);
+  }
+#ifndef NDEBUG
+  {
+    Bitmask toTheLeft = 0;
+    for(i=0; i<pTabList->nSrc; i++){
+      Bitmask m = getMask(&maskSet, pTabList->a[i].iCursor);
+      assert( (m-1)==toTheLeft );
+      toTheLeft |= m;
+    }
+  }
+#endif
+
+  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
+  ** add new virtual terms onto the end of the WHERE clause.  We do not
+  ** want to analyze these virtual terms, so start analyzing at the end
+  ** and work forward so that the added virtual terms are never processed.
+  */
+  exprAnalyzeAll(pTabList, &wc);
+  if( db->mallocFailed ){
+    goto whereBeginNoMem;
+  }
+
+  /* Chose the best index to use for each table in the FROM clause.
+  **
+  ** This loop fills in the following fields:
+  **
+  **   pWInfo->a[].pIdx      The index to use for this level of the loop.
+  **   pWInfo->a[].flags     WHERE_xxx flags associated with pIdx
+  **   pWInfo->a[].nEq       The number of == and IN constraints
+  **   pWInfo->a[].iFrom     When term of the FROM clause is being coded
+  **   pWInfo->a[].iTabCur   The VDBE cursor for the database table
+  **   pWInfo->a[].iIdxCur   The VDBE cursor for the index
+  **
+  ** This loop also figures out the nesting order of tables in the FROM
+  ** clause.
+  */
+  notReady = ~(Bitmask)0;
+  pTabItem = pTabList->a;
+  pLevel = pWInfo->a;
+  andFlags = ~0;
+  WHERETRACE(("*** Optimizer Start ***\n"));
+  for(i=iFrom=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+    Index *pIdx;                /* Index for FROM table at pTabItem */
+    int flags;                  /* Flags asssociated with pIdx */
+    int nEq;                    /* Number of == or IN constraints */
+    double cost;                /* The cost for pIdx */
+    int j;                      /* For looping over FROM tables */
+    Index *pBest = 0;           /* The best index seen so far */
+    int bestFlags = 0;          /* Flags associated with pBest */
+    int bestNEq = 0;            /* nEq associated with pBest */
+    double lowestCost;          /* Cost of the pBest */
+    int bestJ = 0;              /* The value of j */
+    Bitmask m;                  /* Bitmask value for j or bestJ */
+    int once = 0;               /* True when first table is seen */
+    sqlite3_index_info *pIndex; /* Current virtual index */
+
+    lowestCost = SQLITE_BIG_DBL;
+    for(j=iFrom, pTabItem=&pTabList->a[j]; j<pTabList->nSrc; j++, pTabItem++){
+      int doNotReorder;  /* True if this table should not be reordered */
+
+      doNotReorder =  (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;
+      if( once && doNotReorder ) break;
+      m = getMask(&maskSet, pTabItem->iCursor);
+      if( (m & notReady)==0 ){
+        if( j==iFrom ) iFrom++;
+        continue;
+      }
+      assert( pTabItem->pTab );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      if( IsVirtual(pTabItem->pTab) ){
+        sqlite3_index_info **ppIdxInfo = &pWInfo->a[j].pIdxInfo;
+        cost = bestVirtualIndex(pParse, &wc, pTabItem, notReady,
+                                ppOrderBy ? *ppOrderBy : 0, i==0,
+                                ppIdxInfo);
+        flags = WHERE_VIRTUALTABLE;
+        pIndex = *ppIdxInfo;
+        if( pIndex && pIndex->orderByConsumed ){
+          flags = WHERE_VIRTUALTABLE | WHERE_ORDERBY;
+        }
+        pIdx = 0;
+        nEq = 0;
+        if( (SQLITE_BIG_DBL/2.0)<cost ){
+          /* The cost is not allowed to be larger than SQLITE_BIG_DBL (the
+          ** inital value of lowestCost in this loop. If it is, then
+          ** the (cost<lowestCost) test below will never be true and
+          ** pLevel->pBestIdx never set.
+          */ 
+          cost = (SQLITE_BIG_DBL/2.0);
+        }
+      }else 
+#endif
+      {
+        cost = bestIndex(pParse, &wc, pTabItem, notReady,
+                         (i==0 && ppOrderBy) ? *ppOrderBy : 0,
+                         &pIdx, &flags, &nEq);
+        pIndex = 0;
+      }
+      if( cost<lowestCost ){
+        once = 1;
+        lowestCost = cost;
+        pBest = pIdx;
+        bestFlags = flags;
+        bestNEq = nEq;
+        bestJ = j;
+        pLevel->pBestIdx = pIndex;
+      }
+      if( doNotReorder ) break;
+    }
+    WHERETRACE(("*** Optimizer choose table %d for loop %d\n", bestJ,
+           pLevel-pWInfo->a));
+    if( (bestFlags & WHERE_ORDERBY)!=0 ){
+      *ppOrderBy = 0;
+    }
+    andFlags &= bestFlags;
+    pLevel->flags = bestFlags;
+    pLevel->pIdx = pBest;
+    pLevel->nEq = bestNEq;
+    pLevel->aInLoop = 0;
+    pLevel->nIn = 0;
+    if( pBest ){
+      pLevel->iIdxCur = pParse->nTab++;
+    }else{
+      pLevel->iIdxCur = -1;
+    }
+    notReady &= ~getMask(&maskSet, pTabList->a[bestJ].iCursor);
+    pLevel->iFrom = bestJ;
+  }
+  WHERETRACE(("*** Optimizer Finished ***\n"));
+
+  /* If the total query only selects a single row, then the ORDER BY
+  ** clause is irrelevant.
+  */
+  if( (andFlags & WHERE_UNIQUE)!=0 && ppOrderBy ){
+    *ppOrderBy = 0;
+  }
+
+  /* If the caller is an UPDATE or DELETE statement that is requesting
+  ** to use a one-pass algorithm, determine if this is appropriate.
+  ** The one-pass algorithm only works if the WHERE clause constraints
+  ** the statement to update a single row.
+  */
+  assert( (wflags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
+  if( (wflags & WHERE_ONEPASS_DESIRED)!=0 && (andFlags & WHERE_UNIQUE)!=0 ){
+    pWInfo->okOnePass = 1;
+    pWInfo->a[0].flags &= ~WHERE_IDX_ONLY;
+  }
+
+  /* Open all tables in the pTabList and any indices selected for
+  ** searching those tables.
+  */
+  sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
+  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+    Table *pTab;     /* Table to open */
+    Index *pIx;      /* Index used to access pTab (if any) */
+    int iDb;         /* Index of database containing table/index */
+    int iIdxCur = pLevel->iIdxCur;
+
+#ifndef SQLITE_OMIT_EXPLAIN
+    if( pParse->explain==2 ){
+      char *zMsg;
+      struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
+      zMsg = sqlite3MPrintf(db, "TABLE %s", pItem->zName);
+      if( pItem->zAlias ){
+        zMsg = sqlite3MPrintf(db, "%z AS %s", zMsg, pItem->zAlias);
+      }
+      if( (pIx = pLevel->pIdx)!=0 ){
+        zMsg = sqlite3MPrintf(db, "%z WITH INDEX %s", zMsg, pIx->zName);
+      }else if( pLevel->flags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
+        zMsg = sqlite3MPrintf(db, "%z USING PRIMARY KEY", zMsg);
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      else if( pLevel->pBestIdx ){
+        sqlite3_index_info *pBestIdx = pLevel->pBestIdx;
+        zMsg = sqlite3MPrintf(db, "%z VIRTUAL TABLE INDEX %d:%s", zMsg,
+                    pBestIdx->idxNum, pBestIdx->idxStr);
+      }
+#endif
+      if( pLevel->flags & WHERE_ORDERBY ){
+        zMsg = sqlite3MPrintf(db, "%z ORDER BY", zMsg);
+      }
+      sqlite3VdbeAddOp4(v, OP_Explain, i, pLevel->iFrom, 0, zMsg, P4_DYNAMIC);
+    }
+#endif /* SQLITE_OMIT_EXPLAIN */
+    pTabItem = &pTabList->a[pLevel->iFrom];
+    pTab = pTabItem->pTab;
+    iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+    if( pTab->isEphem || pTab->pSelect ) continue;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( pLevel->pBestIdx ){
+      int iCur = pTabItem->iCursor;
+      sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0,
+                        (const char*)pTab->pVtab, P4_VTAB);
+    }else
+#endif
+    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
+      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
+      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
+      if( !pWInfo->okOnePass && pTab->nCol<(sizeof(Bitmask)*8) ){
+        Bitmask b = pTabItem->colUsed;
+        int n = 0;
+        for(; b; b=b>>1, n++){}
+        sqlite3VdbeChangeP2(v, sqlite3VdbeCurrentAddr(v)-2, n);
+        assert( n<=pTab->nCol );
+      }
+    }else{
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+    }
+    pLevel->iTabCur = pTabItem->iCursor;
+    if( (pIx = pLevel->pIdx)!=0 ){
+      KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
+      assert( pIx->pSchema==pTab->pSchema );
+      sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pIx->nColumn+1);
+      sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
+                        (char*)pKey, P4_KEYINFO_HANDOFF);
+      VdbeComment((v, "%s", pIx->zName));
+    }
+    sqlite3CodeVerifySchema(pParse, iDb);
+  }
+  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
+
+  /* Generate the code to do the search.  Each iteration of the for
+  ** loop below generates code for a single nested loop of the VM
+  ** program.
+  */
+  notReady = ~(Bitmask)0;
+  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+    int j;
+    int iCur = pTabItem->iCursor;  /* The VDBE cursor for the table */
+    Index *pIdx;       /* The index we will be using */
+    int nxt;           /* Where to jump to continue with the next IN case */
+    int iIdxCur;       /* The VDBE cursor for the index */
+    int omitTable;     /* True if we use the index only */
+    int bRev;          /* True if we need to scan in reverse order */
+
+    pTabItem = &pTabList->a[pLevel->iFrom];
+    iCur = pTabItem->iCursor;
+    pIdx = pLevel->pIdx;
+    iIdxCur = pLevel->iIdxCur;
+    bRev = (pLevel->flags & WHERE_REVERSE)!=0;
+    omitTable = (pLevel->flags & WHERE_IDX_ONLY)!=0;
+
+    /* Create labels for the "break" and "continue" instructions
+    ** for the current loop.  Jump to brk to break out of a loop.
+    ** Jump to cont to go immediately to the next iteration of the
+    ** loop.
+    **
+    ** When there is an IN operator, we also have a "nxt" label that
+    ** means to continue with the next IN value combination.  When
+    ** there are no IN operators in the constraints, the "nxt" label
+    ** is the same as "brk".
+    */
+    brk = pLevel->brk = pLevel->nxt = sqlite3VdbeMakeLabel(v);
+    cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
+
+    /* If this is the right table of a LEFT OUTER JOIN, allocate and
+    ** initialize a memory cell that records if this table matches any
+    ** row of the left table of the join.
+    */
+    if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
+      pLevel->iLeftJoin = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
+      VdbeComment((v, "init LEFT JOIN no-match flag"));
+    }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( pLevel->pBestIdx ){
+      /* Case 0:  The table is a virtual-table.  Use the VFilter and VNext
+      **          to access the data.
+      */
+      int j;
+      int iReg;   /* P3 Value for OP_VFilter */
+      sqlite3_index_info *pBestIdx = pLevel->pBestIdx;
+      int nConstraint = pBestIdx->nConstraint;
+      struct sqlite3_index_constraint_usage *aUsage =
+                                                  pBestIdx->aConstraintUsage;
+      const struct sqlite3_index_constraint *aConstraint =
+                                                  pBestIdx->aConstraint;
+
+      iReg = sqlite3GetTempRange(pParse, nConstraint+2);
+      for(j=1; j<=nConstraint; j++){
+        int k;
+        for(k=0; k<nConstraint; k++){
+          if( aUsage[k].argvIndex==j ){
+            int iTerm = aConstraint[k].iTermOffset;
+            sqlite3ExprCode(pParse, wc.a[iTerm].pExpr->pRight, iReg+j+1);
+            break;
+          }
+        }
+        if( k==nConstraint ) break;
+      }
+      sqlite3VdbeAddOp2(v, OP_Integer, pBestIdx->idxNum, iReg);
+      sqlite3VdbeAddOp2(v, OP_Integer, j-1, iReg+1);
+      sqlite3VdbeAddOp4(v, OP_VFilter, iCur, brk, iReg, pBestIdx->idxStr,
+                        pBestIdx->needToFreeIdxStr ? P4_MPRINTF : P4_STATIC);
+      sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
+      pBestIdx->needToFreeIdxStr = 0;
+      for(j=0; j<pBestIdx->nConstraint; j++){
+        if( aUsage[j].omit ){
+          int iTerm = aConstraint[j].iTermOffset;
+          disableTerm(pLevel, &wc.a[iTerm]);
+        }
+      }
+      pLevel->op = OP_VNext;
+      pLevel->p1 = iCur;
+      pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+    }else
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+    if( pLevel->flags & WHERE_ROWID_EQ ){
+      /* Case 1:  We can directly reference a single row using an
+      **          equality comparison against the ROWID field.  Or
+      **          we reference multiple rows using a "rowid IN (...)"
+      **          construct.
+      */
+      int r1;
+      pTerm = findTerm(&wc, iCur, -1, notReady, WO_EQ|WO_IN, 0);
+      assert( pTerm!=0 );
+      assert( pTerm->pExpr!=0 );
+      assert( pTerm->leftCursor==iCur );
+      assert( omitTable==0 );
+      r1 = codeEqualityTerm(pParse, pTerm, pLevel, 0);
+      nxt = pLevel->nxt;
+      sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, nxt);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, nxt, r1);
+      VdbeComment((v, "pk"));
+      pLevel->op = OP_Noop;
+    }else if( pLevel->flags & WHERE_ROWID_RANGE ){
+      /* Case 2:  We have an inequality comparison against the ROWID field.
+      */
+      int testOp = OP_Noop;
+      int start;
+      WhereTerm *pStart, *pEnd;
+
+      assert( omitTable==0 );
+      pStart = findTerm(&wc, iCur, -1, notReady, WO_GT|WO_GE, 0);
+      pEnd = findTerm(&wc, iCur, -1, notReady, WO_LT|WO_LE, 0);
+      if( bRev ){
+        pTerm = pStart;
+        pStart = pEnd;
+        pEnd = pTerm;
+      }
+      if( pStart ){
+        Expr *pX;
+        int r1, regFree1;
+        pX = pStart->pExpr;
+        assert( pX!=0 );
+        assert( pStart->leftCursor==iCur );
+        r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &regFree1);
+        sqlite3VdbeAddOp3(v, OP_ForceInt, r1, brk, 
+                             pX->op==TK_LE || pX->op==TK_GT);
+        sqlite3VdbeAddOp3(v, bRev ? OP_MoveLt : OP_MoveGe, iCur, brk, r1);
+        VdbeComment((v, "pk"));
+        sqlite3ReleaseTempReg(pParse, regFree1);
+        disableTerm(pLevel, pStart);
+      }else{
+        sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, brk);
+      }
+      if( pEnd ){
+        Expr *pX;
+        pX = pEnd->pExpr;
+        assert( pX!=0 );
+        assert( pEnd->leftCursor==iCur );
+        pLevel->iMem = ++pParse->nMem;
+        sqlite3ExprCode(pParse, pX->pRight, pLevel->iMem);
+        if( pX->op==TK_LT || pX->op==TK_GT ){
+          testOp = bRev ? OP_Le : OP_Ge;
+        }else{
+          testOp = bRev ? OP_Lt : OP_Gt;
+        }
+        disableTerm(pLevel, pEnd);
+      }
+      start = sqlite3VdbeCurrentAddr(v);
+      pLevel->op = bRev ? OP_Prev : OP_Next;
+      pLevel->p1 = iCur;
+      pLevel->p2 = start;
+      if( testOp!=OP_Noop ){
+        int r1 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
+        /* sqlite3VdbeAddOp2(v, OP_SCopy, pLevel->iMem, 0); */
+        sqlite3VdbeAddOp3(v, testOp, pLevel->iMem, brk, r1);
+        sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
+        sqlite3ReleaseTempReg(pParse, r1);
+      }
+    }else if( pLevel->flags & (WHERE_COLUMN_RANGE|WHERE_COLUMN_EQ) ){
+      /* Case 3: A scan using an index.
+      **
+      **         The WHERE clause may contain zero or more equality 
+      **         terms ("==" or "IN" operators) that refer to the N
+      **         left-most columns of the index. It may also contain
+      **         inequality constraints (>, <, >= or <=) on the indexed
+      **         column that immediately follows the N equalities. Only 
+      **         the right-most column can be an inequality - the rest must
+      **         use the "==" and "IN" operators. For example, if the 
+      **         index is on (x,y,z), then the following clauses are all 
+      **         optimized:
+      **
+      **            x=5
+      **            x=5 AND y=10
+      **            x=5 AND y<10
+      **            x=5 AND y>5 AND y<10
+      **            x=5 AND y=5 AND z<=10
+      **
+      **         The z<10 term of the following cannot be used, only
+      **         the x=5 term:
+      **
+      **            x=5 AND z<10
+      **
+      **         N may be zero if there are inequality constraints.
+      **         If there are no inequality constraints, then N is at
+      **         least one.
+      **
+      **         This case is also used when there are no WHERE clause
+      **         constraints but an index is selected anyway, in order
+      **         to force the output order to conform to an ORDER BY.
+      */  
+      int aStartOp[] = {
+        0,
+        0,
+        OP_Rewind,           /* 2: (!start_constraints && startEq &&  !bRev) */
+        OP_Last,             /* 3: (!start_constraints && startEq &&   bRev) */
+        OP_MoveGt,           /* 4: (start_constraints  && !startEq && !bRev) */
+        OP_MoveLt,           /* 5: (start_constraints  && !startEq &&  bRev) */
+        OP_MoveGe,           /* 6: (start_constraints  &&  startEq && !bRev) */
+        OP_MoveLe            /* 7: (start_constraints  &&  startEq &&  bRev) */
+      };
+      int aEndOp[] = {
+        OP_Noop,             /* 0: (!end_constraints) */
+        OP_IdxGE,            /* 1: (end_constraints && !bRev) */
+        OP_IdxLT             /* 2: (end_constraints && bRev) */
+      };
+      int nEq = pLevel->nEq;
+      int isMinQuery = 0;          /* If this is an optimized SELECT min(x).. */
+      int regBase;                 /* Base register holding constraint values */
+      int r1;                      /* Temp register */
+      WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
+      WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
+      int startEq;                 /* True if range start uses ==, >= or <= */
+      int endEq;                   /* True if range end uses ==, >= or <= */
+      int start_constraints;       /* Start of range is constrained */
+      int k = pIdx->aiColumn[nEq]; /* Column for inequality constraints */
+      int nConstraint;             /* Number of constraint terms */
+      int op;
+
+      /* Generate code to evaluate all constraint terms using == or IN
+      ** and store the values of those terms in an array of registers
+      ** starting at regBase.
+      */
+      regBase = codeAllEqualityTerms(pParse, pLevel, &wc, notReady, 2);
+      nxt = pLevel->nxt;
+
+      /* If this loop satisfies a sort order (pOrderBy) request that 
+      ** was passed to this function to implement a "SELECT min(x) ..." 
+      ** query, then the caller will only allow the loop to run for
+      ** a single iteration. This means that the first row returned
+      ** should not have a NULL value stored in 'x'. If column 'x' is
+      ** the first one after the nEq equality constraints in the index,
+      ** this requires some special handling.
+      */
+      if( (wflags&WHERE_ORDERBY_MIN)!=0
+       && (pLevel->flags&WHERE_ORDERBY)
+       && (pIdx->nColumn>nEq)
+       && (pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq])
+      ){
+        isMinQuery = 1;
+      }
+
+      /* Find any inequality constraint terms for the start and end 
+      ** of the range. 
+      */
+      if( pLevel->flags & WHERE_TOP_LIMIT ){
+        pRangeEnd = findTerm(&wc, iCur, k, notReady, (WO_LT|WO_LE), pIdx);
+      }
+      if( pLevel->flags & WHERE_BTM_LIMIT ){
+        pRangeStart = findTerm(&wc, iCur, k, notReady, (WO_GT|WO_GE), pIdx);
+      }
+
+      /* If we are doing a reverse order scan on an ascending index, or
+      ** a forward order scan on a descending index, interchange the 
+      ** start and end terms (pRangeStart and pRangeEnd).
+      */
+      if( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
+        SWAP(WhereTerm *, pRangeEnd, pRangeStart);
+      }
+
+      testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
+      testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
+      testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
+      testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
+      startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
+      endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
+      start_constraints = pRangeStart || nEq>0;
+
+      /* Seek the index cursor to the start of the range. */
+      nConstraint = nEq;
+      if( pRangeStart ){
+        int dcc = pParse->disableColCache;
+        if( pRangeEnd ){
+          pParse->disableColCache = 1;
+        }
+        sqlite3ExprCode(pParse, pRangeStart->pExpr->pRight, regBase+nEq);
+        pParse->disableColCache = dcc;
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, nxt);
+        nConstraint++;
+      }else if( isMinQuery ){
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+        nConstraint++;
+        startEq = 0;
+        start_constraints = 1;
+      }
+      codeApplyAffinity(pParse, regBase, nConstraint, pIdx);
+      op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
+      assert( op!=0 );
+      testcase( op==OP_Rewind );
+      testcase( op==OP_Last );
+      testcase( op==OP_MoveGt );
+      testcase( op==OP_MoveGe );
+      testcase( op==OP_MoveLe );
+      testcase( op==OP_MoveLt );
+      sqlite3VdbeAddOp4(v, op, iIdxCur, nxt, regBase, 
+                        (char*)nConstraint, P4_INT32);
+
+      /* Load the value for the inequality constraint at the end of the
+      ** range (if any).
+      */
+      nConstraint = nEq;
+      if( pRangeEnd ){
+        sqlite3ExprCode(pParse, pRangeEnd->pExpr->pRight, regBase+nEq);
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, nxt);
+        codeApplyAffinity(pParse, regBase, nEq+1, pIdx);
+        nConstraint++;
+      }
+
+      /* Top of the loop body */
+      pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+
+      /* Check if the index cursor is past the end of the range. */
+      op = aEndOp[(pRangeEnd || nEq) * (1 + bRev)];
+      testcase( op==OP_Noop );
+      testcase( op==OP_IdxGE );
+      testcase( op==OP_IdxLT );
+      sqlite3VdbeAddOp4(v, op, iIdxCur, nxt, regBase,
+                        (char*)nConstraint, P4_INT32);
+      sqlite3VdbeChangeP5(v, endEq!=bRev);
+
+      /* If there are inequality constraints, check that the value
+      ** of the table column that the inequality contrains is not NULL.
+      ** If it is, jump to the next iteration of the loop.
+      */
+      r1 = sqlite3GetTempReg(pParse);
+      testcase( pLevel->flags & WHERE_BTM_LIMIT );
+      testcase( pLevel->flags & WHERE_TOP_LIMIT );
+      if( pLevel->flags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT) ){
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
+        sqlite3VdbeAddOp2(v, OP_IsNull, r1, cont);
+      }
+
+      /* Seek the table cursor, if required */
+      if( !omitTable ){
+        sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, r1);
+        sqlite3VdbeAddOp3(v, OP_MoveGe, iCur, 0, r1);  /* Deferred seek */
+      }
+      sqlite3ReleaseTempReg(pParse, r1);
+
+      /* Record the instruction used to terminate the loop. Disable 
+      ** WHERE clause terms made redundant by the index range scan.
+      */
+      pLevel->op = bRev ? OP_Prev : OP_Next;
+      pLevel->p1 = iIdxCur;
+      disableTerm(pLevel, pRangeStart);
+      disableTerm(pLevel, pRangeEnd);
+    }else{
+      /* Case 4:  There is no usable index.  We must do a complete
+      **          scan of the entire table.
+      */
+      assert( omitTable==0 );
+      assert( bRev==0 );
+      pLevel->op = OP_Next;
+      pLevel->p1 = iCur;
+      pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, OP_Rewind, iCur, brk);
+    }
+    notReady &= ~getMask(&maskSet, iCur);
+
+    /* Insert code to test every subexpression that can be completely
+    ** computed using the current set of tables.
+    */
+    for(pTerm=wc.a, j=wc.nTerm; j>0; j--, pTerm++){
+      Expr *pE;
+      testcase( pTerm->flags & TERM_VIRTUAL );
+      testcase( pTerm->flags & TERM_CODED );
+      if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+      if( (pTerm->prereqAll & notReady)!=0 ) continue;
+      pE = pTerm->pExpr;
+      assert( pE!=0 );
+      if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
+        continue;
+      }
+      sqlite3ExprIfFalse(pParse, pE, cont, SQLITE_JUMPIFNULL);
+      pTerm->flags |= TERM_CODED;
+    }
+
+    /* For a LEFT OUTER JOIN, generate code that will record the fact that
+    ** at least one row of the right table has matched the left table.  
+    */
+    if( pLevel->iLeftJoin ){
+      pLevel->top = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
+      VdbeComment((v, "record LEFT JOIN hit"));
+      sqlite3ExprClearColumnCache(pParse, pLevel->iTabCur);
+      sqlite3ExprClearColumnCache(pParse, pLevel->iIdxCur);
+      for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){
+        testcase( pTerm->flags & TERM_VIRTUAL );
+        testcase( pTerm->flags & TERM_CODED );
+        if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+        if( (pTerm->prereqAll & notReady)!=0 ) continue;
+        assert( pTerm->pExpr );
+        sqlite3ExprIfFalse(pParse, pTerm->pExpr, cont, SQLITE_JUMPIFNULL);
+        pTerm->flags |= TERM_CODED;
+      }
+    }
+  }
+
+#ifdef SQLITE_TEST  /* For testing and debugging use only */
+  /* Record in the query plan information about the current table
+  ** and the index used to access it (if any).  If the table itself
+  ** is not used, its name is just '{}'.  If no index is used
+  ** the index is listed as "{}".  If the primary key is used the
+  ** index name is '*'.
+  */
+  for(i=0; i<pTabList->nSrc; i++){
+    char *z;
+    int n;
+    pLevel = &pWInfo->a[i];
+    pTabItem = &pTabList->a[pLevel->iFrom];
+    z = pTabItem->zAlias;
+    if( z==0 ) z = pTabItem->pTab->zName;
+    n = strlen(z);
+    if( n+nQPlan < sizeof(sqlite3_query_plan)-10 ){
+      if( pLevel->flags & WHERE_IDX_ONLY ){
+        memcpy(&sqlite3_query_plan[nQPlan], "{}", 2);
+        nQPlan += 2;
+      }else{
+        memcpy(&sqlite3_query_plan[nQPlan], z, n);
+        nQPlan += n;
+      }
+      sqlite3_query_plan[nQPlan++] = ' ';
+    }
+    testcase( pLevel->flags & WHERE_ROWID_EQ );
+    testcase( pLevel->flags & WHERE_ROWID_RANGE );
+    if( pLevel->flags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
+      memcpy(&sqlite3_query_plan[nQPlan], "* ", 2);
+      nQPlan += 2;
+    }else if( pLevel->pIdx==0 ){
+      memcpy(&sqlite3_query_plan[nQPlan], "{} ", 3);
+      nQPlan += 3;
+    }else{
+      n = strlen(pLevel->pIdx->zName);
+      if( n+nQPlan < sizeof(sqlite3_query_plan)-2 ){
+        memcpy(&sqlite3_query_plan[nQPlan], pLevel->pIdx->zName, n);
+        nQPlan += n;
+        sqlite3_query_plan[nQPlan++] = ' ';
+      }
+    }
+  }
+  while( nQPlan>0 && sqlite3_query_plan[nQPlan-1]==' ' ){
+    sqlite3_query_plan[--nQPlan] = 0;
+  }
+  sqlite3_query_plan[nQPlan] = 0;
+  nQPlan = 0;
+#endif /* SQLITE_TEST // Testing and debugging use only */
+
+  /* Record the continuation address in the WhereInfo structure.  Then
+  ** clean up and return.
+  */
+  pWInfo->iContinue = cont;
+  whereClauseClear(&wc);
+  return pWInfo;
+
+  /* Jump here if malloc fails */
+whereBeginNoMem:
+  whereClauseClear(&wc);
+  whereInfoFree(pWInfo);
+  return 0;
+}
+
+/*
+** Generate the end of the WHERE loop.  See comments on 
+** sqlite3WhereBegin() for additional information.
+*/
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
+  Vdbe *v = pWInfo->pParse->pVdbe;
+  int i;
+  WhereLevel *pLevel;
+  SrcList *pTabList = pWInfo->pTabList;
+
+  /* Generate loop termination code.
+  */
+  sqlite3ExprClearColumnCache(pWInfo->pParse, -1);
+  for(i=pTabList->nSrc-1; i>=0; i--){
+    pLevel = &pWInfo->a[i];
+    sqlite3VdbeResolveLabel(v, pLevel->cont);
+    if( pLevel->op!=OP_Noop ){
+      sqlite3VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
+    }
+    if( pLevel->nIn ){
+      struct InLoop *pIn;
+      int j;
+      sqlite3VdbeResolveLabel(v, pLevel->nxt);
+      for(j=pLevel->nIn, pIn=&pLevel->aInLoop[j-1]; j>0; j--, pIn--){
+        sqlite3VdbeJumpHere(v, pIn->topAddr+1);
+        sqlite3VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->topAddr);
+        sqlite3VdbeJumpHere(v, pIn->topAddr-1);
+      }
+      sqlite3_free(pLevel->aInLoop);
+    }
+    sqlite3VdbeResolveLabel(v, pLevel->brk);
+    if( pLevel->iLeftJoin ){
+      int addr;
+      addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
+      sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
+      if( pLevel->iIdxCur>=0 ){
+        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
+      }
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->top);
+      sqlite3VdbeJumpHere(v, addr);
+    }
+  }
+
+  /* The "break" point is here, just past the end of the outer loop.
+  ** Set it.
+  */
+  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
+
+  /* Close all of the cursors that were opened by sqlite3WhereBegin.
+  */
+  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+    struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
+    Table *pTab = pTabItem->pTab;
+    assert( pTab!=0 );
+    if( pTab->isEphem || pTab->pSelect ) continue;
+    if( !pWInfo->okOnePass && (pLevel->flags & WHERE_IDX_ONLY)==0 ){
+      sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
+    }
+    if( pLevel->pIdx!=0 ){
+      sqlite3VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
+    }
+
+    /* If this scan uses an index, make code substitutions to read data
+    ** from the index in preference to the table. Sometimes, this means
+    ** the table need never be read from. This is a performance boost,
+    ** as the vdbe level waits until the table is read before actually
+    ** seeking the table cursor to the record corresponding to the current
+    ** position in the index.
+    ** 
+    ** Calls to the code generator in between sqlite3WhereBegin and
+    ** sqlite3WhereEnd will have created code that references the table
+    ** directly.  This loop scans all that code looking for opcodes
+    ** that reference the table and converts them into opcodes that
+    ** reference the index.
+    */
+    if( pLevel->pIdx ){
+      int k, j, last;
+      VdbeOp *pOp;
+      Index *pIdx = pLevel->pIdx;
+      int useIndexOnly = pLevel->flags & WHERE_IDX_ONLY;
+
+      assert( pIdx!=0 );
+      pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
+      last = sqlite3VdbeCurrentAddr(v);
+      for(k=pWInfo->iTop; k<last; k++, pOp++){
+        if( pOp->p1!=pLevel->iTabCur ) continue;
+        if( pOp->opcode==OP_Column ){
+          for(j=0; j<pIdx->nColumn; j++){
+            if( pOp->p2==pIdx->aiColumn[j] ){
+              pOp->p2 = j;
+              pOp->p1 = pLevel->iIdxCur;
+              break;
+            }
+          }
+          assert(!useIndexOnly || j<pIdx->nColumn);
+        }else if( pOp->opcode==OP_Rowid ){
+          pOp->p1 = pLevel->iIdxCur;
+          pOp->opcode = OP_IdxRowid;
+        }else if( pOp->opcode==OP_NullRow && useIndexOnly ){
+          pOp->opcode = OP_Noop;
+        }
+      }
+    }
+  }
+
+  /* Final cleanup
+  */
+  whereInfoFree(pWInfo);
+  return;
+}
+
+/************** End of where.c ***********************************************/
+/************** Begin file parse.c *******************************************/
+/* Driver template for the LEMON parser generator.
+** The author disclaims copyright to this source code.
+*/
+/* First off, code is include which follows the "include" declaration
+** in the input file. */
+
+
+/*
+** An instance of this structure holds information about the
+** LIMIT clause of a SELECT statement.
+*/
+struct LimitVal {
+  Expr *pLimit;    /* The LIMIT expression.  NULL if there is no limit */
+  Expr *pOffset;   /* The OFFSET expression.  NULL if there is none */
+};
+
+/*
+** An instance of this structure is used to store the LIKE,
+** GLOB, NOT LIKE, and NOT GLOB operators.
+*/
+struct LikeOp {
+  Token eOperator;  /* "like" or "glob" or "regexp" */
+  int not;         /* True if the NOT keyword is present */
+};
+
+/*
+** An instance of the following structure describes the event of a
+** TRIGGER.  "a" is the event type, one of TK_UPDATE, TK_INSERT,
+** TK_DELETE, or TK_INSTEAD.  If the event is of the form
+**
+**      UPDATE ON (a,b,c)
+**
+** Then the "b" IdList records the list "a,b,c".
+*/
+struct TrigEvent { int a; IdList * b; };
+
+/*
+** An instance of this structure holds the ATTACH key and the key type.
+*/
+struct AttachKey { int type;  Token key; };
+
+/* Next is all token values, in a form suitable for use by makeheaders.
+** This section will be null unless lemon is run with the -m switch.
+*/
+/* 
+** These constants (all generated automatically by the parser generator)
+** specify the various kinds of tokens (terminals) that the parser
+** understands. 
+**
+** Each symbol here is a terminal symbol in the grammar.
+*/
+/* Make sure the INTERFACE macro is defined.
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/* The next thing included is series of defines which control
+** various aspects of the generated parser.
+**    YYCODETYPE         is the data type used for storing terminal
+**                       and nonterminal numbers.  "unsigned char" is
+**                       used if there are fewer than 250 terminals
+**                       and nonterminals.  "int" is used otherwise.
+**    YYNOCODE           is a number of type YYCODETYPE which corresponds
+**                       to no legal terminal or nonterminal number.  This
+**                       number is used to fill in empty slots of the hash 
+**                       table.
+**    YYFALLBACK         If defined, this indicates that one or more tokens
+**                       have fall-back values which should be used if the
+**                       original value of the token will not parse.
+**    YYACTIONTYPE       is the data type used for storing terminal
+**                       and nonterminal numbers.  "unsigned char" is
+**                       used if there are fewer than 250 rules and
+**                       states combined.  "int" is used otherwise.
+**    sqlite3ParserTOKENTYPE     is the data type used for minor tokens given 
+**                       directly to the parser from the tokenizer.
+**    YYMINORTYPE        is the data type used for all minor tokens.
+**                       This is typically a union of many types, one of
+**                       which is sqlite3ParserTOKENTYPE.  The entry in the union
+**                       for base tokens is called "yy0".
+**    YYSTACKDEPTH       is the maximum depth of the parser's stack.  If
+**                       zero the stack is dynamically sized using realloc()
+**    sqlite3ParserARG_SDECL     A static variable declaration for the %extra_argument
+**    sqlite3ParserARG_PDECL     A parameter declaration for the %extra_argument
+**    sqlite3ParserARG_STORE     Code to store %extra_argument into yypParser
+**    sqlite3ParserARG_FETCH     Code to extract %extra_argument from yypParser
+**    YYNSTATE           the combined number of states.
+**    YYNRULE            the number of rules in the grammar
+**    YYERRORSYMBOL      is the code number of the error symbol.  If not
+**                       defined, then do no error processing.
+*/
+#define YYCODETYPE unsigned char
+#define YYNOCODE 248
+#define YYACTIONTYPE unsigned short int
+#define YYWILDCARD 59
+#define sqlite3ParserTOKENTYPE Token
+typedef union {
+  sqlite3ParserTOKENTYPE yy0;
+  int yy46;
+  struct LikeOp yy72;
+  Expr* yy172;
+  ExprList* yy174;
+  Select* yy219;
+  struct LimitVal yy234;
+  TriggerStep* yy243;
+  struct TrigEvent yy370;
+  SrcList* yy373;
+  struct {int value; int mask;} yy405;
+  Token yy410;
+  IdList* yy432;
+} YYMINORTYPE;
+#ifndef YYSTACKDEPTH
+#define YYSTACKDEPTH 100
+#endif
+#define sqlite3ParserARG_SDECL Parse *pParse;
+#define sqlite3ParserARG_PDECL ,Parse *pParse
+#define sqlite3ParserARG_FETCH Parse *pParse = yypParser->pParse
+#define sqlite3ParserARG_STORE yypParser->pParse = pParse
+#define YYNSTATE 589
+#define YYNRULE 313
+#define YYFALLBACK 1
+#define YY_NO_ACTION      (YYNSTATE+YYNRULE+2)
+#define YY_ACCEPT_ACTION  (YYNSTATE+YYNRULE+1)
+#define YY_ERROR_ACTION   (YYNSTATE+YYNRULE)
+
+/* The yyzerominor constant is used to initialize instances of
+** YYMINORTYPE objects to zero. */
+static const YYMINORTYPE yyzerominor;
+
+/* Next are that tables used to determine what action to take based on the
+** current state and lookahead token.  These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.  
+**
+** Suppose the action integer is N.  Then the action is determined as
+** follows
+**
+**   0 <= N < YYNSTATE                  Shift N.  That is, push the lookahead
+**                                      token onto the stack and goto state N.
+**
+**   YYNSTATE <= N < YYNSTATE+YYNRULE   Reduce by rule N-YYNSTATE.
+**
+**   N == YYNSTATE+YYNRULE              A syntax error has occurred.
+**
+**   N == YYNSTATE+YYNRULE+1            The parser accepts its input.
+**
+**   N == YYNSTATE+YYNRULE+2            No such action.  Denotes unused
+**                                      slots in the yy_action[] table.
+**
+** The action table is constructed as a single large table named yy_action[].
+** Given state S and lookahead X, the action is computed as
+**
+**      yy_action[ yy_shift_ofst[S] + X ]
+**
+** If the index value yy_shift_ofst[S]+X is out of range or if the value
+** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X or if yy_shift_ofst[S]
+** is equal to YY_SHIFT_USE_DFLT, it means that the action is not in the table
+** and that yy_default[S] should be used instead.  
+**
+** The formula above is for computing the action when the lookahead is
+** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the yy_reduce_ofst[] array is used in place of
+** the yy_shift_ofst[] array and YY_REDUCE_USE_DFLT is used in place of
+** YY_SHIFT_USE_DFLT.
+**
+** The following are the tables generated in this section:
+**
+**  yy_action[]        A single table containing all actions.
+**  yy_lookahead[]     A table containing the lookahead for each entry in
+**                     yy_action.  Used to detect hash collisions.
+**  yy_shift_ofst[]    For each state, the offset into yy_action for
+**                     shifting terminals.
+**  yy_reduce_ofst[]   For each state, the offset into yy_action for
+**                     shifting non-terminals after a reduce.
+**  yy_default[]       Default action for each state.
+*/
+static const YYACTIONTYPE yy_action[] = {
+ /*     0 */   292,  903,  124,  588,  409,  172,    2,  418,   61,   61,
+ /*    10 */    61,   61,  519,   63,   63,   63,   63,   64,   64,   65,
+ /*    20 */    65,   65,   66,  210,  447,  212,  425,  431,   68,   63,
+ /*    30 */    63,   63,   63,   64,   64,   65,   65,   65,   66,  210,
+ /*    40 */   391,  388,  396,  451,   60,   59,  297,  435,  436,  432,
+ /*    50 */   432,   62,   62,   61,   61,   61,   61,  263,   63,   63,
+ /*    60 */    63,   63,   64,   64,   65,   65,   65,   66,  210,  292,
+ /*    70 */   493,  494,  418,  489,  208,   82,   67,  420,   69,  154,
+ /*    80 */    63,   63,   63,   63,   64,   64,   65,   65,   65,   66,
+ /*    90 */   210,   67,  462,   69,  154,  425,  431,  574,  264,   58,
+ /*   100 */    64,   64,   65,   65,   65,   66,  210,  397,  398,  422,
+ /*   110 */   422,  422,  292,   60,   59,  297,  435,  436,  432,  432,
+ /*   120 */    62,   62,   61,   61,   61,   61,  317,   63,   63,   63,
+ /*   130 */    63,   64,   64,   65,   65,   65,   66,  210,  425,  431,
+ /*   140 */    94,   65,   65,   65,   66,  210,  396,  210,  414,   34,
+ /*   150 */    56,  298,  442,  443,  410,  418,   60,   59,  297,  435,
+ /*   160 */   436,  432,  432,   62,   62,   61,   61,   61,   61,  208,
+ /*   170 */    63,   63,   63,   63,   64,   64,   65,   65,   65,   66,
+ /*   180 */   210,  292,  372,  524,  295,  572,  113,  408,  522,  451,
+ /*   190 */   331,  317,  407,   20,  244,  340,  519,  396,  478,  531,
+ /*   200 */   505,  447,  212,  571,  570,  245,  530,  425,  431,  149,
+ /*   210 */   150,  397,  398,  414,   41,  211,  151,  533,  488,  489,
+ /*   220 */   418,  568,  569,  420,  292,   60,   59,  297,  435,  436,
+ /*   230 */   432,  432,   62,   62,   61,   61,   61,   61,  317,   63,
+ /*   240 */    63,   63,   63,   64,   64,   65,   65,   65,   66,  210,
+ /*   250 */   425,  431,  447,  333,  215,  422,  422,  422,  363,  299,
+ /*   260 */   414,   41,  397,  398,  366,  567,  211,  292,   60,   59,
+ /*   270 */   297,  435,  436,  432,  432,   62,   62,   61,   61,   61,
+ /*   280 */    61,  396,   63,   63,   63,   63,   64,   64,   65,   65,
+ /*   290 */    65,   66,  210,  425,  431,  491,  300,  524,  474,   66,
+ /*   300 */   210,  214,  474,  229,  411,  286,  534,   20,  449,  523,
+ /*   310 */   168,   60,   59,  297,  435,  436,  432,  432,   62,   62,
+ /*   320 */    61,   61,   61,   61,  474,   63,   63,   63,   63,   64,
+ /*   330 */    64,   65,   65,   65,   66,  210,  209,  480,  317,   77,
+ /*   340 */   292,  239,  300,   55,  484,  490,  397,  398,  181,  547,
+ /*   350 */   494,  345,  348,  349,   67,  152,   69,  154,  339,  524,
+ /*   360 */   414,   35,  350,  241,  221,  370,  425,  431,  579,   20,
+ /*   370 */   164,  118,  243,  343,  248,  344,  176,  322,  442,  443,
+ /*   380 */   414,    3,   80,  252,   60,   59,  297,  435,  436,  432,
+ /*   390 */   432,   62,   62,   61,   61,   61,   61,  174,   63,   63,
+ /*   400 */    63,   63,   64,   64,   65,   65,   65,   66,  210,  292,
+ /*   410 */   221,  550,  236,  487,  510,  353,  317,  118,  243,  343,
+ /*   420 */   248,  344,  176,  181,  317,  532,  345,  348,  349,  252,
+ /*   430 */   223,  415,  155,  464,  511,  425,  431,  350,  414,   34,
+ /*   440 */   465,  211,  177,  175,  160,  525,  414,   34,  338,  549,
+ /*   450 */   449,  323,  168,   60,   59,  297,  435,  436,  432,  432,
+ /*   460 */    62,   62,   61,   61,   61,   61,  415,   63,   63,   63,
+ /*   470 */    63,   64,   64,   65,   65,   65,   66,  210,  292,  542,
+ /*   480 */   335,  517,  504,  541,  456,  572,  302,   19,  331,  144,
+ /*   490 */   317,  390,  317,  330,    2,  362,  457,  294,  483,  373,
+ /*   500 */   269,  268,  252,  571,  425,  431,  589,  391,  388,  458,
+ /*   510 */   208,  495,  414,   49,  414,   49,  303,  586,  894,  230,
+ /*   520 */   894,  496,   60,   59,  297,  435,  436,  432,  432,   62,
+ /*   530 */    62,   61,   61,   61,   61,  201,   63,   63,   63,   63,
+ /*   540 */    64,   64,   65,   65,   65,   66,  210,  292,  317,  181,
+ /*   550 */   439,  255,  345,  348,  349,  370,  153,  583,  308,  251,
+ /*   560 */   309,  452,   76,  350,   78,  382,  211,  426,  427,  415,
+ /*   570 */   414,   27,  319,  425,  431,  440,    1,   22,  586,  893,
+ /*   580 */   396,  893,  544,  478,  320,  263,  438,  438,  429,  430,
+ /*   590 */   415,   60,   59,  297,  435,  436,  432,  432,   62,   62,
+ /*   600 */    61,   61,   61,   61,  237,   63,   63,   63,   63,   64,
+ /*   610 */    64,   65,   65,   65,   66,  210,  292,  428,  583,  374,
+ /*   620 */   224,   93,  517,    9,  159,  396,  557,  396,  456,   67,
+ /*   630 */   396,   69,  154,  399,  400,  401,  320,  328,  438,  438,
+ /*   640 */   457,  336,  425,  431,  361,  397,  398,  320,  433,  438,
+ /*   650 */   438,  582,  291,  458,  238,  327,  318,  222,  546,  292,
+ /*   660 */    60,   59,  297,  435,  436,  432,  432,   62,   62,   61,
+ /*   670 */    61,   61,   61,  225,   63,   63,   63,   63,   64,   64,
+ /*   680 */    65,   65,   65,   66,  210,  425,  431,  482,  313,  392,
+ /*   690 */   397,  398,  397,  398,  207,  397,  398,  825,  273,  517,
+ /*   700 */   251,  200,  292,   60,   59,  297,  435,  436,  432,  432,
+ /*   710 */    62,   62,   61,   61,   61,   61,  470,   63,   63,   63,
+ /*   720 */    63,   64,   64,   65,   65,   65,   66,  210,  425,  431,
+ /*   730 */   171,  160,  263,  263,  304,  415,  276,  395,  274,  263,
+ /*   740 */   517,  517,  263,  517,  192,  292,   60,   70,  297,  435,
+ /*   750 */   436,  432,  432,   62,   62,   61,   61,   61,   61,  379,
+ /*   760 */    63,   63,   63,   63,   64,   64,   65,   65,   65,   66,
+ /*   770 */   210,  425,  431,  384,  559,  305,  306,  251,  415,  320,
+ /*   780 */   560,  438,  438,  561,  540,  360,  540,  387,  292,  196,
+ /*   790 */    59,  297,  435,  436,  432,  432,   62,   62,   61,   61,
+ /*   800 */    61,   61,  371,   63,   63,   63,   63,   64,   64,   65,
+ /*   810 */    65,   65,   66,  210,  425,  431,  396,  275,  251,  251,
+ /*   820 */   172,  250,  418,  415,  386,  367,  178,  179,  180,  469,
+ /*   830 */   311,  123,  156,    5,  297,  435,  436,  432,  432,   62,
+ /*   840 */    62,   61,   61,   61,   61,  317,   63,   63,   63,   63,
+ /*   850 */    64,   64,   65,   65,   65,   66,  210,   72,  324,  194,
+ /*   860 */     4,  317,  263,  317,  296,  263,  415,  414,   28,  317,
+ /*   870 */   257,  317,  321,   72,  324,  317,    4,  119,  165,  177,
+ /*   880 */   296,  397,  398,  414,   23,  414,   32,  418,  321,  326,
+ /*   890 */   421,  414,   53,  414,   52,  317,  158,  414,   98,  451,
+ /*   900 */   317,  263,  317,  277,  317,  326,  378,  471,  261,  317,
+ /*   910 */   259,   18,  478,  445,  445,  451,  317,  414,   96,   75,
+ /*   920 */    74,  469,  414,  101,  414,  102,  414,  112,   73,  315,
+ /*   930 */   316,  414,  114,  420,  294,   75,   74,  481,  414,   16,
+ /*   940 */   381,  317,  279,  467,   73,  315,  316,   72,  324,  420,
+ /*   950 */     4,  208,  317,  183,  296,  317,  186,  128,   84,  208,
+ /*   960 */     8,  341,  321,  414,   99,  422,  422,  422,  423,  424,
+ /*   970 */    11,  623,  380,  307,  414,   33,  413,  414,   97,  326,
+ /*   980 */   412,  422,  422,  422,  423,  424,   11,  415,  413,  451,
+ /*   990 */   415,  162,  412,  317,  499,  500,  226,  227,  228,  104,
+ /*  1000 */   448,  476,  317,  173,  507,  317,  509,  508,  317,   75,
+ /*  1010 */    74,  329,  205,   21,  281,  414,   24,  418,   73,  315,
+ /*  1020 */   316,  282,  317,  420,  414,   54,  460,  414,  115,  317,
+ /*  1030 */   414,  116,  502,  203,  147,  549,  514,  468,  128,  202,
+ /*  1040 */   317,  473,  204,  317,  414,  117,  317,  477,  317,  584,
+ /*  1050 */   317,  414,   25,  317,  249,  422,  422,  422,  423,  424,
+ /*  1060 */    11,  506,  414,   36,  512,  414,   37,  317,  414,   26,
+ /*  1070 */   414,   38,  414,   39,  526,  414,   40,  317,  254,  317,
+ /*  1080 */   128,  317,  418,  317,  256,  377,  278,  268,  585,  414,
+ /*  1090 */    42,  293,  317,  352,  317,  128,  208,  513,  258,  414,
+ /*  1100 */    43,  414,   44,  414,   29,  414,   30,  545,  260,  128,
+ /*  1110 */   317,  553,  317,  173,  414,   45,  414,   46,  317,  262,
+ /*  1120 */   383,  554,  317,   91,  564,  317,   91,  317,  581,  189,
+ /*  1130 */   290,  357,  414,   47,  414,   48,  267,  365,  368,  369,
+ /*  1140 */   414,   31,  270,  271,  414,   10,  272,  414,   50,  414,
+ /*  1150 */    51,  556,  566,  280,  283,  284,  578,  146,  419,  405,
+ /*  1160 */   231,  505,  444,  325,  516,  463,  163,  446,  552,  394,
+ /*  1170 */   466,  563,  246,  515,  518,  520,  402,  403,  404,    7,
+ /*  1180 */   314,   84,  232,  334,  347,   83,  332,   57,  170,   79,
+ /*  1190 */   213,  461,  125,   85,  337,  342,  492,  502,  497,  301,
+ /*  1200 */   498,  416,  105,  219,  247,  218,  503,  501,  233,  220,
+ /*  1210 */   287,  234,  527,  528,  235,  529,  417,  521,  354,  288,
+ /*  1220 */   184,  121,  185,  240,  535,  475,  242,  356,  187,  479,
+ /*  1230 */   188,  358,  537,   88,  190,  548,  364,  193,  132,  376,
+ /*  1240 */   555,  375,  133,  134,  135,  310,  562,  138,  136,  575,
+ /*  1250 */   576,  577,  580,  100,  393,  406,  217,  142,  624,  625,
+ /*  1260 */   103,  141,  265,  166,  167,  434,   71,  453,  441,  437,
+ /*  1270 */   450,  143,  538,  157,  120,  454,  161,  472,  455,  169,
+ /*  1280 */   459,   81,    6,   12,   13,   92,   95,  126,  216,  127,
+ /*  1290 */   111,  485,  486,   17,   86,  346,  106,  122,  253,  107,
+ /*  1300 */    87,  108,  182,  245,  355,  145,  351,  536,  129,  359,
+ /*  1310 */   312,  130,  543,  173,  539,  266,  191,  109,  289,  551,
+ /*  1320 */   195,   14,  131,  198,  197,  558,  137,  199,  139,  140,
+ /*  1330 */    15,  565,   89,   90,  573,  110,  385,  206,  148,  389,
+ /*  1340 */   285,  587,
+};
+static const YYCODETYPE yy_lookahead[] = {
+ /*     0 */    16,  139,  140,  141,  168,   21,  144,   23,   69,   70,
+ /*    10 */    71,   72,  176,   74,   75,   76,   77,   78,   79,   80,
+ /*    20 */    81,   82,   83,   84,   78,   79,   42,   43,   73,   74,
+ /*    30 */    75,   76,   77,   78,   79,   80,   81,   82,   83,   84,
+ /*    40 */     1,    2,   23,   58,   60,   61,   62,   63,   64,   65,
+ /*    50 */    66,   67,   68,   69,   70,   71,   72,  147,   74,   75,
+ /*    60 */    76,   77,   78,   79,   80,   81,   82,   83,   84,   16,
+ /*    70 */   185,  186,   88,   88,  110,   22,  217,   92,  219,  220,
+ /*    80 */    74,   75,   76,   77,   78,   79,   80,   81,   82,   83,
+ /*    90 */    84,  217,  218,  219,  220,   42,   43,  238,  188,   46,
+ /*   100 */    78,   79,   80,   81,   82,   83,   84,   88,   89,  124,
+ /*   110 */   125,  126,   16,   60,   61,   62,   63,   64,   65,   66,
+ /*   120 */    67,   68,   69,   70,   71,   72,  147,   74,   75,   76,
+ /*   130 */    77,   78,   79,   80,   81,   82,   83,   84,   42,   43,
+ /*   140 */    44,   80,   81,   82,   83,   84,   23,   84,  169,  170,
+ /*   150 */    19,  164,  165,  166,   23,   23,   60,   61,   62,   63,
+ /*   160 */    64,   65,   66,   67,   68,   69,   70,   71,   72,  110,
+ /*   170 */    74,   75,   76,   77,   78,   79,   80,   81,   82,   83,
+ /*   180 */    84,   16,  123,  147,  150,  147,   21,  167,  168,   58,
+ /*   190 */   211,  147,  156,  157,   92,  216,  176,   23,  147,  176,
+ /*   200 */   177,   78,   79,  165,  166,  103,  183,   42,   43,   78,
+ /*   210 */    79,   88,   89,  169,  170,  228,  180,  181,  169,   88,
+ /*   220 */    88,   98,   99,   92,   16,   60,   61,   62,   63,   64,
+ /*   230 */    65,   66,   67,   68,   69,   70,   71,   72,  147,   74,
+ /*   240 */    75,   76,   77,   78,   79,   80,   81,   82,   83,   84,
+ /*   250 */    42,   43,   78,  209,  210,  124,  125,  126,  224,  208,
+ /*   260 */   169,  170,   88,   89,  230,  227,  228,   16,   60,   61,
+ /*   270 */    62,   63,   64,   65,   66,   67,   68,   69,   70,   71,
+ /*   280 */    72,   23,   74,   75,   76,   77,   78,   79,   80,   81,
+ /*   290 */    82,   83,   84,   42,   43,  160,   16,  147,  161,   83,
+ /*   300 */    84,  210,  161,  153,  169,  158,  156,  157,  161,  162,
+ /*   310 */   163,   60,   61,   62,   63,   64,   65,   66,   67,   68,
+ /*   320 */    69,   70,   71,   72,  161,   74,   75,   76,   77,   78,
+ /*   330 */    79,   80,   81,   82,   83,   84,  192,  200,  147,  131,
+ /*   340 */    16,  200,   16,  199,   20,  169,   88,   89,   90,  185,
+ /*   350 */   186,   93,   94,   95,  217,   22,  219,  220,  147,  147,
+ /*   360 */   169,  170,  104,  200,   84,  147,   42,   43,  156,  157,
+ /*   370 */    90,   91,   92,   93,   94,   95,   96,  164,  165,  166,
+ /*   380 */   169,  170,  131,  103,   60,   61,   62,   63,   64,   65,
+ /*   390 */    66,   67,   68,   69,   70,   71,   72,  155,   74,   75,
+ /*   400 */    76,   77,   78,   79,   80,   81,   82,   83,   84,   16,
+ /*   410 */    84,   11,  221,   20,   30,   16,  147,   91,   92,   93,
+ /*   420 */    94,   95,   96,   90,  147,  181,   93,   94,   95,  103,
+ /*   430 */   212,  189,  155,   27,   50,   42,   43,  104,  169,  170,
+ /*   440 */    34,  228,   43,  201,  202,  181,  169,  170,  206,   49,
+ /*   450 */   161,  162,  163,   60,   61,   62,   63,   64,   65,   66,
+ /*   460 */    67,   68,   69,   70,   71,   72,  189,   74,   75,   76,
+ /*   470 */    77,   78,   79,   80,   81,   82,   83,   84,   16,   25,
+ /*   480 */   211,  147,   20,   29,   12,  147,  102,   19,  211,   21,
+ /*   490 */   147,  141,  147,  216,  144,   41,   24,   98,   20,   99,
+ /*   500 */   100,  101,  103,  165,   42,   43,    0,    1,    2,   37,
+ /*   510 */   110,   39,  169,  170,  169,  170,  182,   19,   20,  190,
+ /*   520 */    22,   49,   60,   61,   62,   63,   64,   65,   66,   67,
+ /*   530 */    68,   69,   70,   71,   72,  155,   74,   75,   76,   77,
+ /*   540 */    78,   79,   80,   81,   82,   83,   84,   16,  147,   90,
+ /*   550 */    20,   20,   93,   94,   95,  147,  155,   59,  215,  225,
+ /*   560 */   215,   20,  130,  104,  132,  227,  228,   42,   43,  189,
+ /*   570 */   169,  170,   16,   42,   43,   20,   19,   22,   19,   20,
+ /*   580 */    23,   22,   18,  147,  106,  147,  108,  109,   63,   64,
+ /*   590 */   189,   60,   61,   62,   63,   64,   65,   66,   67,   68,
+ /*   600 */    69,   70,   71,   72,  147,   74,   75,   76,   77,   78,
+ /*   610 */    79,   80,   81,   82,   83,   84,   16,   92,   59,   55,
+ /*   620 */   212,   21,  147,   19,  147,   23,  188,   23,   12,  217,
+ /*   630 */    23,  219,  220,    7,    8,    9,  106,  186,  108,  109,
+ /*   640 */    24,  147,   42,   43,  208,   88,   89,  106,   92,  108,
+ /*   650 */   109,  244,  245,   37,  147,   39,  147,  182,   94,   16,
+ /*   660 */    60,   61,   62,   63,   64,   65,   66,   67,   68,   69,
+ /*   670 */    70,   71,   72,  145,   74,   75,   76,   77,   78,   79,
+ /*   680 */    80,   81,   82,   83,   84,   42,   43,   80,  142,  143,
+ /*   690 */    88,   89,   88,   89,  148,   88,   89,  133,   14,  147,
+ /*   700 */   225,  155,   16,   60,   61,   62,   63,   64,   65,   66,
+ /*   710 */    67,   68,   69,   70,   71,   72,  114,   74,   75,   76,
+ /*   720 */    77,   78,   79,   80,   81,   82,   83,   84,   42,   43,
+ /*   730 */   201,  202,  147,  147,  182,  189,   52,  147,   54,  147,
+ /*   740 */   147,  147,  147,  147,  155,   16,   60,   61,   62,   63,
+ /*   750 */    64,   65,   66,   67,   68,   69,   70,   71,   72,  213,
+ /*   760 */    74,   75,   76,   77,   78,   79,   80,   81,   82,   83,
+ /*   770 */    84,   42,   43,  188,  188,  182,  182,  225,  189,  106,
+ /*   780 */   188,  108,  109,  188,   99,  100,  101,  241,   16,  155,
+ /*   790 */    61,   62,   63,   64,   65,   66,   67,   68,   69,   70,
+ /*   800 */    71,   72,  213,   74,   75,   76,   77,   78,   79,   80,
+ /*   810 */    81,   82,   83,   84,   42,   43,   23,  133,  225,  225,
+ /*   820 */    21,  225,   23,  189,  239,  236,   99,  100,  101,   22,
+ /*   830 */   242,  243,  155,  191,   62,   63,   64,   65,   66,   67,
+ /*   840 */    68,   69,   70,   71,   72,  147,   74,   75,   76,   77,
+ /*   850 */    78,   79,   80,   81,   82,   83,   84,   16,   17,   22,
+ /*   860 */    19,  147,  147,  147,   23,  147,  189,  169,  170,  147,
+ /*   870 */    14,  147,   31,   16,   17,  147,   19,  147,   19,   43,
+ /*   880 */    23,   88,   89,  169,  170,  169,  170,   88,   31,   48,
+ /*   890 */   147,  169,  170,  169,  170,  147,   89,  169,  170,   58,
+ /*   900 */   147,  147,  147,  188,  147,   48,  188,  114,   52,  147,
+ /*   910 */    54,   19,  147,  124,  125,   58,  147,  169,  170,   78,
+ /*   920 */    79,  114,  169,  170,  169,  170,  169,  170,   87,   88,
+ /*   930 */    89,  169,  170,   92,   98,   78,   79,   80,  169,  170,
+ /*   940 */    91,  147,  188,   22,   87,   88,   89,   16,   17,   92,
+ /*   950 */    19,  110,  147,  155,   23,  147,  155,   22,  121,  110,
+ /*   960 */    68,   80,   31,  169,  170,  124,  125,  126,  127,  128,
+ /*   970 */   129,  112,  123,  208,  169,  170,  107,  169,  170,   48,
+ /*   980 */   111,  124,  125,  126,  127,  128,  129,  189,  107,   58,
+ /*   990 */   189,    5,  111,  147,    7,    8,   10,   11,   12,   13,
+ /*  1000 */   161,   20,  147,   22,  178,  147,   91,   92,  147,   78,
+ /*  1010 */    79,  147,   26,   19,   28,  169,  170,   23,   87,   88,
+ /*  1020 */    89,   35,  147,   92,  169,  170,  147,  169,  170,  147,
+ /*  1030 */   169,  170,   97,   47,  113,   49,   20,  203,   22,   53,
+ /*  1040 */   147,  147,   56,  147,  169,  170,  147,  147,  147,   20,
+ /*  1050 */   147,  169,  170,  147,  147,  124,  125,  126,  127,  128,
+ /*  1060 */   129,  147,  169,  170,  178,  169,  170,  147,  169,  170,
+ /*  1070 */   169,  170,  169,  170,  147,  169,  170,  147,   20,  147,
+ /*  1080 */    22,  147,   88,  147,  147,   99,  100,  101,   59,  169,
+ /*  1090 */   170,  105,  147,   20,  147,   22,  110,  178,  147,  169,
+ /*  1100 */   170,  169,  170,  169,  170,  169,  170,   20,  147,   22,
+ /*  1110 */   147,   20,  147,   22,  169,  170,  169,  170,  147,  147,
+ /*  1120 */   134,   20,  147,   22,   20,  147,   22,  147,   20,  232,
+ /*  1130 */    22,  233,  169,  170,  169,  170,  147,  147,  147,  147,
+ /*  1140 */   169,  170,  147,  147,  169,  170,  147,  169,  170,  169,
+ /*  1150 */   170,  147,  147,  147,  147,  147,  147,  191,  161,  149,
+ /*  1160 */   193,  177,  229,  223,  161,  172,    6,  229,  194,  146,
+ /*  1170 */   172,  194,  172,  172,  172,  161,  146,  146,  146,   22,
+ /*  1180 */   154,  121,  194,  118,  173,  119,  116,  120,  112,  130,
+ /*  1190 */   222,  152,  152,   98,  115,   98,  171,   97,  171,   40,
+ /*  1200 */   179,  189,   19,   84,  171,  226,  171,  173,  195,  226,
+ /*  1210 */   174,  196,  171,  171,  197,  171,  198,  179,   15,  174,
+ /*  1220 */   151,   60,  151,  204,  152,  205,  204,  152,  151,  205,
+ /*  1230 */   152,   38,  152,  130,  151,  184,  152,  184,   19,   15,
+ /*  1240 */   194,  152,  187,  187,  187,  152,  194,  184,  187,   33,
+ /*  1250 */   152,  152,  137,  159,    1,   20,  175,  214,  112,  112,
+ /*  1260 */   175,  214,  234,  112,  112,   92,   19,   11,   20,  107,
+ /*  1270 */    20,   19,  235,   19,   32,   20,  112,  114,   20,   22,
+ /*  1280 */    20,   22,  117,   22,  117,  237,  237,   19,   44,   20,
+ /*  1290 */   240,   20,   20,  231,   19,   44,   19,  243,   20,   19,
+ /*  1300 */    19,   19,   96,  103,   16,   21,   44,   17,   98,   36,
+ /*  1310 */   246,   45,   45,   22,   51,  133,   98,   19,    5,    1,
+ /*  1320 */   122,   19,  102,   14,  113,   17,  113,  115,  102,  122,
+ /*  1330 */    19,  123,   68,   68,   20,   14,   57,  135,   19,    3,
+ /*  1340 */   136,    4,
+};
+#define YY_SHIFT_USE_DFLT (-62)
+#define YY_SHIFT_MAX 389
+static const short yy_shift_ofst[] = {
+ /*     0 */    39,  841,  986,  -16,  841,  931,  931,  258,  123,  -36,
+ /*    10 */    96,  931,  931,  931,  931,  931,  -45,  400,  174,   19,
+ /*    20 */   132,  -54,  -54,   53,  165,  208,  251,  324,  393,  462,
+ /*    30 */   531,  600,  643,  686,  643,  643,  643,  643,  643,  643,
+ /*    40 */   643,  643,  643,  643,  643,  643,  643,  643,  643,  643,
+ /*    50 */   643,  643,  729,  772,  772,  857,  931,  931,  931,  931,
+ /*    60 */   931,  931,  931,  931,  931,  931,  931,  931,  931,  931,
+ /*    70 */   931,  931,  931,  931,  931,  931,  931,  931,  931,  931,
+ /*    80 */   931,  931,  931,  931,  931,  931,  931,  931,  931,  931,
+ /*    90 */   931,  931,  931,  931,  931,  931,  -61,  -61,    6,    6,
+ /*   100 */   280,   22,   61,  399,  564,   19,   19,   19,   19,   19,
+ /*   110 */    19,   19,  216,  132,   63,  -62,  -62,  -62,  131,  326,
+ /*   120 */   472,  472,  498,  559,  506,  799,   19,  799,   19,   19,
+ /*   130 */    19,   19,   19,   19,   19,   19,   19,   19,   19,   19,
+ /*   140 */    19,  849,   59,  -36,  -36,  -36,  -62,  -62,  -62,  -15,
+ /*   150 */   -15,  333,  459,  478,  557,  530,  541,  616,  602,  793,
+ /*   160 */   604,  607,  626,   19,   19,  881,   19,   19,  994,   19,
+ /*   170 */    19,  807,   19,   19,  673,  807,   19,   19,  384,  384,
+ /*   180 */   384,   19,   19,  673,   19,   19,  673,   19,  454,  685,
+ /*   190 */    19,   19,  673,   19,   19,   19,  673,   19,   19,   19,
+ /*   200 */   673,  673,   19,   19,   19,   19,   19,  468,  869,  921,
+ /*   210 */   132,  789,  789,  432,  406,  406,  406,  836,  406,  132,
+ /*   220 */   406,  132,  935,  837,  837, 1160, 1160, 1160, 1160, 1157,
+ /*   230 */   -36, 1060, 1065, 1066, 1070, 1067, 1059, 1076, 1076, 1095,
+ /*   240 */  1079, 1095, 1079, 1097, 1097, 1159, 1097, 1100, 1097, 1183,
+ /*   250 */  1119, 1119, 1159, 1097, 1097, 1097, 1183, 1203, 1076, 1203,
+ /*   260 */  1076, 1203, 1076, 1076, 1193, 1103, 1203, 1076, 1161, 1161,
+ /*   270 */  1219, 1060, 1076, 1224, 1224, 1224, 1224, 1060, 1161, 1219,
+ /*   280 */  1076, 1216, 1216, 1076, 1076, 1115,  -62,  -62,  -62,  -62,
+ /*   290 */   -62,  -62,  525,  684,  727,  856,  859,  556,  555,  981,
+ /*   300 */   102,  987,  915, 1016, 1058, 1073, 1087, 1091, 1101, 1104,
+ /*   310 */   892, 1108, 1029, 1253, 1235, 1146, 1147, 1151, 1152, 1173,
+ /*   320 */  1162, 1247, 1248, 1250, 1252, 1256, 1254, 1255, 1257, 1258,
+ /*   330 */  1260, 1259, 1165, 1261, 1167, 1259, 1163, 1268, 1269, 1164,
+ /*   340 */  1271, 1272, 1242, 1244, 1275, 1251, 1277, 1278, 1280, 1281,
+ /*   350 */  1262, 1282, 1206, 1200, 1288, 1290, 1284, 1210, 1273, 1263,
+ /*   360 */  1266, 1291, 1267, 1182, 1218, 1298, 1313, 1318, 1220, 1264,
+ /*   370 */  1265, 1198, 1302, 1211, 1309, 1212, 1308, 1213, 1226, 1207,
+ /*   380 */  1311, 1208, 1314, 1321, 1279, 1202, 1204, 1319, 1336, 1337,
+};
+#define YY_REDUCE_USE_DFLT (-165)
+#define YY_REDUCE_MAX 291
+static const short yy_reduce_ofst[] = {
+ /*     0 */  -138,  277,  546,  137,  401,  -21,   44,   36,   38,  242,
+ /*    10 */  -141,  191,   91,  269,  343,  345, -126,  589,  338,  150,
+ /*    20 */   147,  -13,  213,  412,  412,  412,  412,  412,  412,  412,
+ /*    30 */   412,  412,  412,  412,  412,  412,  412,  412,  412,  412,
+ /*    40 */   412,  412,  412,  412,  412,  412,  412,  412,  412,  412,
+ /*    50 */   412,  412,  412,  412,  412,  211,  698,  714,  716,  722,
+ /*    60 */   724,  728,  748,  753,  755,  757,  762,  769,  794,  805,
+ /*    70 */   808,  846,  855,  858,  861,  875,  882,  893,  896,  899,
+ /*    80 */   901,  903,  906,  920,  930,  932,  934,  936,  945,  947,
+ /*    90 */   963,  965,  971,  975,  978,  980,  412,  412,  412,  412,
+ /*   100 */    20,  412,  412,   23,   34,  334,  475,  552,  593,  594,
+ /*   110 */   585,  212,  412,  289,  412,  412,  412,  412,  135, -164,
+ /*   120 */  -115,  164,  407,  407,  350,  141,   51,  163,  596,  -90,
+ /*   130 */   436,  218,  765,  438,  586,  592,  595,  715,  718,  408,
+ /*   140 */   754,  380,  634,  677,  798,  801,  144,  529,  588,   49,
+ /*   150 */   176,  244,  264,  329,  457,  329,  329,  451,  477,  494,
+ /*   160 */   507,  509,  528,  590,  730,  642,  509,  743,  839,  864,
+ /*   170 */   879,  834,  894,  900,  329,  834,  907,  914,  826,  886,
+ /*   180 */   919,  927,  937,  329,  951,  961,  329,  972,  897,  898,
+ /*   190 */   989,  990,  329,  991,  992,  995,  329,  996,  999, 1004,
+ /*   200 */   329,  329, 1005, 1006, 1007, 1008, 1009, 1010,  966,  967,
+ /*   210 */   997,  933,  938,  940,  993,  998, 1000,  984, 1001, 1003,
+ /*   220 */  1002, 1014, 1011,  974,  977, 1023, 1030, 1031, 1032, 1026,
+ /*   230 */  1012,  988, 1013, 1015, 1017, 1018,  968, 1039, 1040, 1019,
+ /*   240 */  1020, 1022, 1024, 1025, 1027, 1021, 1033, 1034, 1035, 1036,
+ /*   250 */   979,  983, 1038, 1041, 1042, 1044, 1045, 1069, 1072, 1071,
+ /*   260 */  1075, 1077, 1078, 1080, 1028, 1037, 1083, 1084, 1051, 1053,
+ /*   270 */  1043, 1046, 1089, 1055, 1056, 1057, 1061, 1052, 1063, 1047,
+ /*   280 */  1093, 1048, 1049, 1098, 1099, 1050, 1094, 1081, 1085, 1062,
+ /*   290 */  1054, 1064,
+};
+static const YYACTIONTYPE yy_default[] = {
+ /*     0 */   595,  820,  902,  710,  902,  820,  902,  902,  848,  714,
+ /*    10 */   877,  818,  902,  902,  902,  902,  792,  902,  848,  902,
+ /*    20 */   626,  848,  848,  743,  902,  902,  902,  902,  902,  902,
+ /*    30 */   902,  902,  744,  902,  822,  817,  813,  815,  814,  821,
+ /*    40 */   745,  734,  741,  748,  726,  861,  750,  751,  757,  758,
+ /*    50 */   878,  876,  780,  779,  798,  902,  902,  902,  902,  902,
+ /*    60 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*    70 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*    80 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*    90 */   902,  902,  902,  902,  902,  902,  782,  804,  781,  791,
+ /*   100 */   619,  783,  784,  679,  614,  902,  902,  902,  902,  902,
+ /*   110 */   902,  902,  785,  902,  786,  799,  800,  801,  902,  902,
+ /*   120 */   902,  902,  902,  902,  595,  710,  902,  710,  902,  902,
+ /*   130 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   140 */   902,  902,  902,  902,  902,  902,  704,  714,  895,  902,
+ /*   150 */   902,  670,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   160 */   902,  902,  602,  600,  902,  702,  902,  902,  628,  902,
+ /*   170 */   902,  712,  902,  902,  717,  718,  902,  902,  902,  902,
+ /*   180 */   902,  902,  902,  616,  902,  902,  691,  902,  854,  902,
+ /*   190 */   902,  902,  868,  902,  902,  902,  866,  902,  902,  902,
+ /*   200 */   693,  753,  834,  902,  881,  883,  902,  902,  702,  711,
+ /*   210 */   902,  902,  902,  816,  737,  737,  737,  649,  737,  902,
+ /*   220 */   737,  902,  652,  747,  747,  599,  599,  599,  599,  669,
+ /*   230 */   902,  747,  738,  740,  730,  742,  902,  719,  719,  727,
+ /*   240 */   729,  727,  729,  681,  681,  666,  681,  652,  681,  826,
+ /*   250 */   831,  831,  666,  681,  681,  681,  826,  611,  719,  611,
+ /*   260 */   719,  611,  719,  719,  858,  860,  611,  719,  683,  683,
+ /*   270 */   759,  747,  719,  690,  690,  690,  690,  747,  683,  759,
+ /*   280 */   719,  880,  880,  719,  719,  888,  636,  654,  654,  863,
+ /*   290 */   895,  900,  902,  902,  902,  902,  766,  902,  902,  902,
+ /*   300 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   310 */   841,  902,  902,  902,  902,  771,  767,  902,  768,  902,
+ /*   320 */   696,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   330 */   902,  819,  902,  731,  902,  739,  902,  902,  902,  902,
+ /*   340 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   350 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   360 */   856,  857,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   370 */   902,  902,  902,  902,  902,  902,  902,  902,  902,  902,
+ /*   380 */   902,  902,  902,  902,  887,  902,  902,  890,  596,  902,
+ /*   390 */   590,  593,  592,  594,  598,  601,  623,  624,  625,  603,
+ /*   400 */   604,  605,  606,  607,  608,  609,  615,  617,  635,  637,
+ /*   410 */   621,  639,  700,  701,  763,  694,  695,  699,  622,  774,
+ /*   420 */   765,  769,  770,  772,  773,  787,  788,  790,  796,  803,
+ /*   430 */   806,  789,  794,  795,  797,  802,  805,  697,  698,  809,
+ /*   440 */   629,  630,  633,  634,  844,  846,  845,  847,  632,  631,
+ /*   450 */   775,  778,  811,  812,  869,  870,  871,  872,  873,  807,
+ /*   460 */   720,  810,  793,  732,  735,  736,  733,  703,  713,  722,
+ /*   470 */   723,  724,  725,  708,  709,  715,  728,  761,  762,  716,
+ /*   480 */   705,  706,  707,  808,  764,  776,  777,  640,  641,  771,
+ /*   490 */   642,  643,  644,  682,  685,  686,  687,  645,  664,  667,
+ /*   500 */   668,  646,  653,  647,  648,  655,  656,  657,  660,  661,
+ /*   510 */   662,  663,  658,  659,  827,  828,  832,  830,  829,  650,
+ /*   520 */   651,  665,  638,  627,  620,  671,  674,  675,  676,  677,
+ /*   530 */   678,  680,  672,  673,  618,  610,  612,  721,  850,  859,
+ /*   540 */   855,  851,  852,  853,  613,  823,  824,  684,  755,  756,
+ /*   550 */   849,  862,  864,  760,  865,  867,  892,  688,  689,  692,
+ /*   560 */   833,  874,  746,  749,  752,  754,  835,  836,  837,  838,
+ /*   570 */   839,  842,  843,  840,  875,  879,  882,  884,  885,  886,
+ /*   580 */   889,  891,  896,  897,  898,  901,  899,  597,  591,
+};
+#define YY_SZ_ACTTAB (int)(sizeof(yy_action)/sizeof(yy_action[0]))
+
+/* The next table maps tokens into fallback tokens.  If a construct
+** like the following:
+** 
+**      %fallback ID X Y Z.
+**
+** appears in the grammer, then ID becomes a fallback token for X, Y,
+** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+*/
+#ifdef YYFALLBACK
+static const YYCODETYPE yyFallback[] = {
+    0,  /*          $ => nothing */
+    0,  /*       SEMI => nothing */
+   23,  /*    EXPLAIN => ID */
+   23,  /*      QUERY => ID */
+   23,  /*       PLAN => ID */
+   23,  /*      BEGIN => ID */
+    0,  /* TRANSACTION => nothing */
+   23,  /*   DEFERRED => ID */
+   23,  /*  IMMEDIATE => ID */
+   23,  /*  EXCLUSIVE => ID */
+    0,  /*     COMMIT => nothing */
+   23,  /*        END => ID */
+    0,  /*   ROLLBACK => nothing */
+    0,  /*     CREATE => nothing */
+    0,  /*      TABLE => nothing */
+   23,  /*         IF => ID */
+    0,  /*        NOT => nothing */
+    0,  /*     EXISTS => nothing */
+   23,  /*       TEMP => ID */
+    0,  /*         LP => nothing */
+    0,  /*         RP => nothing */
+    0,  /*         AS => nothing */
+    0,  /*      COMMA => nothing */
+    0,  /*         ID => nothing */
+   23,  /*      ABORT => ID */
+   23,  /*      AFTER => ID */
+   23,  /*    ANALYZE => ID */
+   23,  /*        ASC => ID */
+   23,  /*     ATTACH => ID */
+   23,  /*     BEFORE => ID */
+   23,  /*    CASCADE => ID */
+   23,  /*       CAST => ID */
+   23,  /*   CONFLICT => ID */
+   23,  /*   DATABASE => ID */
+   23,  /*       DESC => ID */
+   23,  /*     DETACH => ID */
+   23,  /*       EACH => ID */
+   23,  /*       FAIL => ID */
+   23,  /*        FOR => ID */
+   23,  /*     IGNORE => ID */
+   23,  /*  INITIALLY => ID */
+   23,  /*    INSTEAD => ID */
+   23,  /*    LIKE_KW => ID */
+   23,  /*      MATCH => ID */
+   23,  /*        KEY => ID */
+   23,  /*         OF => ID */
+   23,  /*     OFFSET => ID */
+   23,  /*     PRAGMA => ID */
+   23,  /*      RAISE => ID */
+   23,  /*    REPLACE => ID */
+   23,  /*   RESTRICT => ID */
+   23,  /*        ROW => ID */
+   23,  /*    TRIGGER => ID */
+   23,  /*     VACUUM => ID */
+   23,  /*       VIEW => ID */
+   23,  /*    VIRTUAL => ID */
+   23,  /*    REINDEX => ID */
+   23,  /*     RENAME => ID */
+   23,  /*   CTIME_KW => ID */
+    0,  /*        ANY => nothing */
+    0,  /*         OR => nothing */
+    0,  /*        AND => nothing */
+    0,  /*         IS => nothing */
+    0,  /*    BETWEEN => nothing */
+    0,  /*         IN => nothing */
+    0,  /*     ISNULL => nothing */
+    0,  /*    NOTNULL => nothing */
+    0,  /*         NE => nothing */
+    0,  /*         EQ => nothing */
+    0,  /*         GT => nothing */
+    0,  /*         LE => nothing */
+    0,  /*         LT => nothing */
+    0,  /*         GE => nothing */
+    0,  /*     ESCAPE => nothing */
+    0,  /*     BITAND => nothing */
+    0,  /*      BITOR => nothing */
+    0,  /*     LSHIFT => nothing */
+    0,  /*     RSHIFT => nothing */
+    0,  /*       PLUS => nothing */
+    0,  /*      MINUS => nothing */
+    0,  /*       STAR => nothing */
+    0,  /*      SLASH => nothing */
+    0,  /*        REM => nothing */
+    0,  /*     CONCAT => nothing */
+    0,  /*    COLLATE => nothing */
+    0,  /*     UMINUS => nothing */
+    0,  /*      UPLUS => nothing */
+    0,  /*     BITNOT => nothing */
+    0,  /*     STRING => nothing */
+    0,  /*    JOIN_KW => nothing */
+    0,  /* CONSTRAINT => nothing */
+    0,  /*    DEFAULT => nothing */
+    0,  /*       NULL => nothing */
+    0,  /*    PRIMARY => nothing */
+    0,  /*     UNIQUE => nothing */
+    0,  /*      CHECK => nothing */
+    0,  /* REFERENCES => nothing */
+    0,  /*   AUTOINCR => nothing */
+    0,  /*         ON => nothing */
+    0,  /*     DELETE => nothing */
+    0,  /*     UPDATE => nothing */
+    0,  /*     INSERT => nothing */
+    0,  /*        SET => nothing */
+    0,  /* DEFERRABLE => nothing */
+    0,  /*    FOREIGN => nothing */
+    0,  /*       DROP => nothing */
+    0,  /*      UNION => nothing */
+    0,  /*        ALL => nothing */
+    0,  /*     EXCEPT => nothing */
+    0,  /*  INTERSECT => nothing */
+    0,  /*     SELECT => nothing */
+    0,  /*   DISTINCT => nothing */
+    0,  /*        DOT => nothing */
+    0,  /*       FROM => nothing */
+    0,  /*       JOIN => nothing */
+    0,  /*      USING => nothing */
+    0,  /*      ORDER => nothing */
+    0,  /*         BY => nothing */
+    0,  /*      GROUP => nothing */
+    0,  /*     HAVING => nothing */
+    0,  /*      LIMIT => nothing */
+    0,  /*      WHERE => nothing */
+    0,  /*       INTO => nothing */
+    0,  /*     VALUES => nothing */
+    0,  /*    INTEGER => nothing */
+    0,  /*      FLOAT => nothing */
+    0,  /*       BLOB => nothing */
+    0,  /*   REGISTER => nothing */
+    0,  /*   VARIABLE => nothing */
+    0,  /*       CASE => nothing */
+    0,  /*       WHEN => nothing */
+    0,  /*       THEN => nothing */
+    0,  /*       ELSE => nothing */
+    0,  /*      INDEX => nothing */
+    0,  /*      ALTER => nothing */
+    0,  /*         TO => nothing */
+    0,  /*        ADD => nothing */
+    0,  /*   COLUMNKW => nothing */
+};
+#endif /* YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack.  Information stored includes:
+**
+**   +  The state number for the parser at this level of the stack.
+**
+**   +  The value of the token stored at this level of the stack.
+**      (In other words, the "major" token.)
+**
+**   +  The semantic value stored at this level of the stack.  This is
+**      the information used by the action routines in the grammar.
+**      It is sometimes called the "minor" token.
+*/
+struct yyStackEntry {
+  int stateno;       /* The state-number */
+  int major;         /* The major token value.  This is the code
+                     ** number for the token at this stack level */
+  YYMINORTYPE minor; /* The user-supplied minor token value.  This
+                     ** is the value of the token  */
+};
+typedef struct yyStackEntry yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct yyParser {
+  int yyidx;                    /* Index of top element in stack */
+  int yyerrcnt;                 /* Shifts left before out of the error */
+  sqlite3ParserARG_SDECL                /* A place to hold %extra_argument */
+#if YYSTACKDEPTH<=0
+  int yystksz;                  /* Current side of the stack */
+  yyStackEntry *yystack;        /* The parser's stack */
+#else
+  yyStackEntry yystack[YYSTACKDEPTH];  /* The parser's stack */
+#endif
+};
+typedef struct yyParser yyParser;
+
+#ifndef NDEBUG
+static FILE *yyTraceFILE = 0;
+static char *yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/* 
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message.  Tracing is turned off
+** by making either argument NULL 
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+**      If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+**      line of trace output.  If NULL, then tracing is
+**      turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3ParserTrace(FILE *TraceFILE, char *zTracePrompt){
+  yyTraceFILE = TraceFILE;
+  yyTracePrompt = zTracePrompt;
+  if( yyTraceFILE==0 ) yyTracePrompt = 0;
+  else if( yyTracePrompt==0 ) yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required.  The following table supplies these names */
+static const char *const yyTokenName[] = { 
+  "$",             "SEMI",          "EXPLAIN",       "QUERY",       
+  "PLAN",          "BEGIN",         "TRANSACTION",   "DEFERRED",    
+  "IMMEDIATE",     "EXCLUSIVE",     "COMMIT",        "END",         
+  "ROLLBACK",      "CREATE",        "TABLE",         "IF",          
+  "NOT",           "EXISTS",        "TEMP",          "LP",          
+  "RP",            "AS",            "COMMA",         "ID",          
+  "ABORT",         "AFTER",         "ANALYZE",       "ASC",         
+  "ATTACH",        "BEFORE",        "CASCADE",       "CAST",        
+  "CONFLICT",      "DATABASE",      "DESC",          "DETACH",      
+  "EACH",          "FAIL",          "FOR",           "IGNORE",      
+  "INITIALLY",     "INSTEAD",       "LIKE_KW",       "MATCH",       
+  "KEY",           "OF",            "OFFSET",        "PRAGMA",      
+  "RAISE",         "REPLACE",       "RESTRICT",      "ROW",         
+  "TRIGGER",       "VACUUM",        "VIEW",          "VIRTUAL",     
+  "REINDEX",       "RENAME",        "CTIME_KW",      "ANY",         
+  "OR",            "AND",           "IS",            "BETWEEN",     
+  "IN",            "ISNULL",        "NOTNULL",       "NE",          
+  "EQ",            "GT",            "LE",            "LT",          
+  "GE",            "ESCAPE",        "BITAND",        "BITOR",       
+  "LSHIFT",        "RSHIFT",        "PLUS",          "MINUS",       
+  "STAR",          "SLASH",         "REM",           "CONCAT",      
+  "COLLATE",       "UMINUS",        "UPLUS",         "BITNOT",      
+  "STRING",        "JOIN_KW",       "CONSTRAINT",    "DEFAULT",     
+  "NULL",          "PRIMARY",       "UNIQUE",        "CHECK",       
+  "REFERENCES",    "AUTOINCR",      "ON",            "DELETE",      
+  "UPDATE",        "INSERT",        "SET",           "DEFERRABLE",  
+  "FOREIGN",       "DROP",          "UNION",         "ALL",         
+  "EXCEPT",        "INTERSECT",     "SELECT",        "DISTINCT",    
+  "DOT",           "FROM",          "JOIN",          "USING",       
+  "ORDER",         "BY",            "GROUP",         "HAVING",      
+  "LIMIT",         "WHERE",         "INTO",          "VALUES",      
+  "INTEGER",       "FLOAT",         "BLOB",          "REGISTER",    
+  "VARIABLE",      "CASE",          "WHEN",          "THEN",        
+  "ELSE",          "INDEX",         "ALTER",         "TO",          
+  "ADD",           "COLUMNKW",      "error",         "input",       
+  "cmdlist",       "ecmd",          "cmdx",          "cmd",         
+  "explain",       "transtype",     "trans_opt",     "nm",          
+  "create_table",  "create_table_args",  "temp",          "ifnotexists", 
+  "dbnm",          "columnlist",    "conslist_opt",  "select",      
+  "column",        "columnid",      "type",          "carglist",    
+  "id",            "ids",           "typetoken",     "typename",    
+  "signed",        "plus_num",      "minus_num",     "carg",        
+  "ccons",         "term",          "expr",          "onconf",      
+  "sortorder",     "autoinc",       "idxlist_opt",   "refargs",     
+  "defer_subclause",  "refarg",        "refact",        "init_deferred_pred_opt",
+  "conslist",      "tcons",         "idxlist",       "defer_subclause_opt",
+  "orconf",        "resolvetype",   "raisetype",     "ifexists",    
+  "fullname",      "oneselect",     "multiselect_op",  "distinct",    
+  "selcollist",    "from",          "where_opt",     "groupby_opt", 
+  "having_opt",    "orderby_opt",   "limit_opt",     "sclp",        
+  "as",            "seltablist",    "stl_prefix",    "joinop",      
+  "on_opt",        "using_opt",     "seltablist_paren",  "joinop2",     
+  "inscollist",    "sortlist",      "sortitem",      "nexprlist",   
+  "setlist",       "insert_cmd",    "inscollist_opt",  "itemlist",    
+  "exprlist",      "likeop",        "escape",        "between_op",  
+  "in_op",         "case_operand",  "case_exprlist",  "case_else",   
+  "uniqueflag",    "idxitem",       "collate",       "nmnum",       
+  "plus_opt",      "number",        "trigger_decl",  "trigger_cmd_list",
+  "trigger_time",  "trigger_event",  "foreach_clause",  "when_clause", 
+  "trigger_cmd",   "database_kw_opt",  "key_opt",       "add_column_fullname",
+  "kwcolumn_opt",  "create_vtab",   "vtabarglist",   "vtabarg",     
+  "vtabargtoken",  "lp",            "anylist",     
+};
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const yyRuleName[] = {
+ /*   0 */ "input ::= cmdlist",
+ /*   1 */ "cmdlist ::= cmdlist ecmd",
+ /*   2 */ "cmdlist ::= ecmd",
+ /*   3 */ "cmdx ::= cmd",
+ /*   4 */ "ecmd ::= SEMI",
+ /*   5 */ "ecmd ::= explain cmdx SEMI",
+ /*   6 */ "explain ::=",
+ /*   7 */ "explain ::= EXPLAIN",
+ /*   8 */ "explain ::= EXPLAIN QUERY PLAN",
+ /*   9 */ "cmd ::= BEGIN transtype trans_opt",
+ /*  10 */ "trans_opt ::=",
+ /*  11 */ "trans_opt ::= TRANSACTION",
+ /*  12 */ "trans_opt ::= TRANSACTION nm",
+ /*  13 */ "transtype ::=",
+ /*  14 */ "transtype ::= DEFERRED",
+ /*  15 */ "transtype ::= IMMEDIATE",
+ /*  16 */ "transtype ::= EXCLUSIVE",
+ /*  17 */ "cmd ::= COMMIT trans_opt",
+ /*  18 */ "cmd ::= END trans_opt",
+ /*  19 */ "cmd ::= ROLLBACK trans_opt",
+ /*  20 */ "cmd ::= create_table create_table_args",
+ /*  21 */ "create_table ::= CREATE temp TABLE ifnotexists nm dbnm",
+ /*  22 */ "ifnotexists ::=",
+ /*  23 */ "ifnotexists ::= IF NOT EXISTS",
+ /*  24 */ "temp ::= TEMP",
+ /*  25 */ "temp ::=",
+ /*  26 */ "create_table_args ::= LP columnlist conslist_opt RP",
+ /*  27 */ "create_table_args ::= AS select",
+ /*  28 */ "columnlist ::= columnlist COMMA column",
+ /*  29 */ "columnlist ::= column",
+ /*  30 */ "column ::= columnid type carglist",
+ /*  31 */ "columnid ::= nm",
+ /*  32 */ "id ::= ID",
+ /*  33 */ "ids ::= ID|STRING",
+ /*  34 */ "nm ::= ID",
+ /*  35 */ "nm ::= STRING",
+ /*  36 */ "nm ::= JOIN_KW",
+ /*  37 */ "type ::=",
+ /*  38 */ "type ::= typetoken",
+ /*  39 */ "typetoken ::= typename",
+ /*  40 */ "typetoken ::= typename LP signed RP",
+ /*  41 */ "typetoken ::= typename LP signed COMMA signed RP",
+ /*  42 */ "typename ::= ids",
+ /*  43 */ "typename ::= typename ids",
+ /*  44 */ "signed ::= plus_num",
+ /*  45 */ "signed ::= minus_num",
+ /*  46 */ "carglist ::= carglist carg",
+ /*  47 */ "carglist ::=",
+ /*  48 */ "carg ::= CONSTRAINT nm ccons",
+ /*  49 */ "carg ::= ccons",
+ /*  50 */ "ccons ::= DEFAULT term",
+ /*  51 */ "ccons ::= DEFAULT LP expr RP",
+ /*  52 */ "ccons ::= DEFAULT PLUS term",
+ /*  53 */ "ccons ::= DEFAULT MINUS term",
+ /*  54 */ "ccons ::= DEFAULT id",
+ /*  55 */ "ccons ::= NULL onconf",
+ /*  56 */ "ccons ::= NOT NULL onconf",
+ /*  57 */ "ccons ::= PRIMARY KEY sortorder onconf autoinc",
+ /*  58 */ "ccons ::= UNIQUE onconf",
+ /*  59 */ "ccons ::= CHECK LP expr RP",
+ /*  60 */ "ccons ::= REFERENCES nm idxlist_opt refargs",
+ /*  61 */ "ccons ::= defer_subclause",
+ /*  62 */ "ccons ::= COLLATE ids",
+ /*  63 */ "autoinc ::=",
+ /*  64 */ "autoinc ::= AUTOINCR",
+ /*  65 */ "refargs ::=",
+ /*  66 */ "refargs ::= refargs refarg",
+ /*  67 */ "refarg ::= MATCH nm",
+ /*  68 */ "refarg ::= ON DELETE refact",
+ /*  69 */ "refarg ::= ON UPDATE refact",
+ /*  70 */ "refarg ::= ON INSERT refact",
+ /*  71 */ "refact ::= SET NULL",
+ /*  72 */ "refact ::= SET DEFAULT",
+ /*  73 */ "refact ::= CASCADE",
+ /*  74 */ "refact ::= RESTRICT",
+ /*  75 */ "defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt",
+ /*  76 */ "defer_subclause ::= DEFERRABLE init_deferred_pred_opt",
+ /*  77 */ "init_deferred_pred_opt ::=",
+ /*  78 */ "init_deferred_pred_opt ::= INITIALLY DEFERRED",
+ /*  79 */ "init_deferred_pred_opt ::= INITIALLY IMMEDIATE",
+ /*  80 */ "conslist_opt ::=",
+ /*  81 */ "conslist_opt ::= COMMA conslist",
+ /*  82 */ "conslist ::= conslist COMMA tcons",
+ /*  83 */ "conslist ::= conslist tcons",
+ /*  84 */ "conslist ::= tcons",
+ /*  85 */ "tcons ::= CONSTRAINT nm",
+ /*  86 */ "tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf",
+ /*  87 */ "tcons ::= UNIQUE LP idxlist RP onconf",
+ /*  88 */ "tcons ::= CHECK LP expr RP onconf",
+ /*  89 */ "tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt",
+ /*  90 */ "defer_subclause_opt ::=",
+ /*  91 */ "defer_subclause_opt ::= defer_subclause",
+ /*  92 */ "onconf ::=",
+ /*  93 */ "onconf ::= ON CONFLICT resolvetype",
+ /*  94 */ "orconf ::=",
+ /*  95 */ "orconf ::= OR resolvetype",
+ /*  96 */ "resolvetype ::= raisetype",
+ /*  97 */ "resolvetype ::= IGNORE",
+ /*  98 */ "resolvetype ::= REPLACE",
+ /*  99 */ "cmd ::= DROP TABLE ifexists fullname",
+ /* 100 */ "ifexists ::= IF EXISTS",
+ /* 101 */ "ifexists ::=",
+ /* 102 */ "cmd ::= CREATE temp VIEW ifnotexists nm dbnm AS select",
+ /* 103 */ "cmd ::= DROP VIEW ifexists fullname",
+ /* 104 */ "cmd ::= select",
+ /* 105 */ "select ::= oneselect",
+ /* 106 */ "select ::= select multiselect_op oneselect",
+ /* 107 */ "multiselect_op ::= UNION",
+ /* 108 */ "multiselect_op ::= UNION ALL",
+ /* 109 */ "multiselect_op ::= EXCEPT|INTERSECT",
+ /* 110 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt",
+ /* 111 */ "distinct ::= DISTINCT",
+ /* 112 */ "distinct ::= ALL",
+ /* 113 */ "distinct ::=",
+ /* 114 */ "sclp ::= selcollist COMMA",
+ /* 115 */ "sclp ::=",
+ /* 116 */ "selcollist ::= sclp expr as",
+ /* 117 */ "selcollist ::= sclp STAR",
+ /* 118 */ "selcollist ::= sclp nm DOT STAR",
+ /* 119 */ "as ::= AS nm",
+ /* 120 */ "as ::= ids",
+ /* 121 */ "as ::=",
+ /* 122 */ "from ::=",
+ /* 123 */ "from ::= FROM seltablist",
+ /* 124 */ "stl_prefix ::= seltablist joinop",
+ /* 125 */ "stl_prefix ::=",
+ /* 126 */ "seltablist ::= stl_prefix nm dbnm as on_opt using_opt",
+ /* 127 */ "seltablist ::= stl_prefix LP seltablist_paren RP as on_opt using_opt",
+ /* 128 */ "seltablist_paren ::= select",
+ /* 129 */ "seltablist_paren ::= seltablist",
+ /* 130 */ "dbnm ::=",
+ /* 131 */ "dbnm ::= DOT nm",
+ /* 132 */ "fullname ::= nm dbnm",
+ /* 133 */ "joinop ::= COMMA|JOIN",
+ /* 134 */ "joinop ::= JOIN_KW JOIN",
+ /* 135 */ "joinop ::= JOIN_KW nm JOIN",
+ /* 136 */ "joinop ::= JOIN_KW nm nm JOIN",
+ /* 137 */ "on_opt ::= ON expr",
+ /* 138 */ "on_opt ::=",
+ /* 139 */ "using_opt ::= USING LP inscollist RP",
+ /* 140 */ "using_opt ::=",
+ /* 141 */ "orderby_opt ::=",
+ /* 142 */ "orderby_opt ::= ORDER BY sortlist",
+ /* 143 */ "sortlist ::= sortlist COMMA sortitem sortorder",
+ /* 144 */ "sortlist ::= sortitem sortorder",
+ /* 145 */ "sortitem ::= expr",
+ /* 146 */ "sortorder ::= ASC",
+ /* 147 */ "sortorder ::= DESC",
+ /* 148 */ "sortorder ::=",
+ /* 149 */ "groupby_opt ::=",
+ /* 150 */ "groupby_opt ::= GROUP BY nexprlist",
+ /* 151 */ "having_opt ::=",
+ /* 152 */ "having_opt ::= HAVING expr",
+ /* 153 */ "limit_opt ::=",
+ /* 154 */ "limit_opt ::= LIMIT expr",
+ /* 155 */ "limit_opt ::= LIMIT expr OFFSET expr",
+ /* 156 */ "limit_opt ::= LIMIT expr COMMA expr",
+ /* 157 */ "cmd ::= DELETE FROM fullname where_opt",
+ /* 158 */ "where_opt ::=",
+ /* 159 */ "where_opt ::= WHERE expr",
+ /* 160 */ "cmd ::= UPDATE orconf fullname SET setlist where_opt",
+ /* 161 */ "setlist ::= setlist COMMA nm EQ expr",
+ /* 162 */ "setlist ::= nm EQ expr",
+ /* 163 */ "cmd ::= insert_cmd INTO fullname inscollist_opt VALUES LP itemlist RP",
+ /* 164 */ "cmd ::= insert_cmd INTO fullname inscollist_opt select",
+ /* 165 */ "cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES",
+ /* 166 */ "insert_cmd ::= INSERT orconf",
+ /* 167 */ "insert_cmd ::= REPLACE",
+ /* 168 */ "itemlist ::= itemlist COMMA expr",
+ /* 169 */ "itemlist ::= expr",
+ /* 170 */ "inscollist_opt ::=",
+ /* 171 */ "inscollist_opt ::= LP inscollist RP",
+ /* 172 */ "inscollist ::= inscollist COMMA nm",
+ /* 173 */ "inscollist ::= nm",
+ /* 174 */ "expr ::= term",
+ /* 175 */ "expr ::= LP expr RP",
+ /* 176 */ "term ::= NULL",
+ /* 177 */ "expr ::= ID",
+ /* 178 */ "expr ::= JOIN_KW",
+ /* 179 */ "expr ::= nm DOT nm",
+ /* 180 */ "expr ::= nm DOT nm DOT nm",
+ /* 181 */ "term ::= INTEGER|FLOAT|BLOB",
+ /* 182 */ "term ::= STRING",
+ /* 183 */ "expr ::= REGISTER",
+ /* 184 */ "expr ::= VARIABLE",
+ /* 185 */ "expr ::= expr COLLATE ids",
+ /* 186 */ "expr ::= CAST LP expr AS typetoken RP",
+ /* 187 */ "expr ::= ID LP distinct exprlist RP",
+ /* 188 */ "expr ::= ID LP STAR RP",
+ /* 189 */ "term ::= CTIME_KW",
+ /* 190 */ "expr ::= expr AND expr",
+ /* 191 */ "expr ::= expr OR expr",
+ /* 192 */ "expr ::= expr LT|GT|GE|LE expr",
+ /* 193 */ "expr ::= expr EQ|NE expr",
+ /* 194 */ "expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr",
+ /* 195 */ "expr ::= expr PLUS|MINUS expr",
+ /* 196 */ "expr ::= expr STAR|SLASH|REM expr",
+ /* 197 */ "expr ::= expr CONCAT expr",
+ /* 198 */ "likeop ::= LIKE_KW",
+ /* 199 */ "likeop ::= NOT LIKE_KW",
+ /* 200 */ "likeop ::= MATCH",
+ /* 201 */ "likeop ::= NOT MATCH",
+ /* 202 */ "escape ::= ESCAPE expr",
+ /* 203 */ "escape ::=",
+ /* 204 */ "expr ::= expr likeop expr escape",
+ /* 205 */ "expr ::= expr ISNULL|NOTNULL",
+ /* 206 */ "expr ::= expr IS NULL",
+ /* 207 */ "expr ::= expr NOT NULL",
+ /* 208 */ "expr ::= expr IS NOT NULL",
+ /* 209 */ "expr ::= NOT expr",
+ /* 210 */ "expr ::= BITNOT expr",
+ /* 211 */ "expr ::= MINUS expr",
+ /* 212 */ "expr ::= PLUS expr",
+ /* 213 */ "between_op ::= BETWEEN",
+ /* 214 */ "between_op ::= NOT BETWEEN",
+ /* 215 */ "expr ::= expr between_op expr AND expr",
+ /* 216 */ "in_op ::= IN",
+ /* 217 */ "in_op ::= NOT IN",
+ /* 218 */ "expr ::= expr in_op LP exprlist RP",
+ /* 219 */ "expr ::= LP select RP",
+ /* 220 */ "expr ::= expr in_op LP select RP",
+ /* 221 */ "expr ::= expr in_op nm dbnm",
+ /* 222 */ "expr ::= EXISTS LP select RP",
+ /* 223 */ "expr ::= CASE case_operand case_exprlist case_else END",
+ /* 224 */ "case_exprlist ::= case_exprlist WHEN expr THEN expr",
+ /* 225 */ "case_exprlist ::= WHEN expr THEN expr",
+ /* 226 */ "case_else ::= ELSE expr",
+ /* 227 */ "case_else ::=",
+ /* 228 */ "case_operand ::= expr",
+ /* 229 */ "case_operand ::=",
+ /* 230 */ "exprlist ::= nexprlist",
+ /* 231 */ "exprlist ::=",
+ /* 232 */ "nexprlist ::= nexprlist COMMA expr",
+ /* 233 */ "nexprlist ::= expr",
+ /* 234 */ "cmd ::= CREATE uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP",
+ /* 235 */ "uniqueflag ::= UNIQUE",
+ /* 236 */ "uniqueflag ::=",
+ /* 237 */ "idxlist_opt ::=",
+ /* 238 */ "idxlist_opt ::= LP idxlist RP",
+ /* 239 */ "idxlist ::= idxlist COMMA idxitem collate sortorder",
+ /* 240 */ "idxlist ::= idxitem collate sortorder",
+ /* 241 */ "idxitem ::= nm",
+ /* 242 */ "collate ::=",
+ /* 243 */ "collate ::= COLLATE ids",
+ /* 244 */ "cmd ::= DROP INDEX ifexists fullname",
+ /* 245 */ "cmd ::= VACUUM",
+ /* 246 */ "cmd ::= VACUUM nm",
+ /* 247 */ "cmd ::= PRAGMA nm dbnm EQ nmnum",
+ /* 248 */ "cmd ::= PRAGMA nm dbnm EQ ON",
+ /* 249 */ "cmd ::= PRAGMA nm dbnm EQ DELETE",
+ /* 250 */ "cmd ::= PRAGMA nm dbnm EQ minus_num",
+ /* 251 */ "cmd ::= PRAGMA nm dbnm LP nmnum RP",
+ /* 252 */ "cmd ::= PRAGMA nm dbnm",
+ /* 253 */ "nmnum ::= plus_num",
+ /* 254 */ "nmnum ::= nm",
+ /* 255 */ "plus_num ::= plus_opt number",
+ /* 256 */ "minus_num ::= MINUS number",
+ /* 257 */ "number ::= INTEGER|FLOAT",
+ /* 258 */ "plus_opt ::= PLUS",
+ /* 259 */ "plus_opt ::=",
+ /* 260 */ "cmd ::= CREATE trigger_decl BEGIN trigger_cmd_list END",
+ /* 261 */ "trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause",
+ /* 262 */ "trigger_time ::= BEFORE",
+ /* 263 */ "trigger_time ::= AFTER",
+ /* 264 */ "trigger_time ::= INSTEAD OF",
+ /* 265 */ "trigger_time ::=",
+ /* 266 */ "trigger_event ::= DELETE|INSERT",
+ /* 267 */ "trigger_event ::= UPDATE",
+ /* 268 */ "trigger_event ::= UPDATE OF inscollist",
+ /* 269 */ "foreach_clause ::=",
+ /* 270 */ "foreach_clause ::= FOR EACH ROW",
+ /* 271 */ "when_clause ::=",
+ /* 272 */ "when_clause ::= WHEN expr",
+ /* 273 */ "trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI",
+ /* 274 */ "trigger_cmd_list ::=",
+ /* 275 */ "trigger_cmd ::= UPDATE orconf nm SET setlist where_opt",
+ /* 276 */ "trigger_cmd ::= insert_cmd INTO nm inscollist_opt VALUES LP itemlist RP",
+ /* 277 */ "trigger_cmd ::= insert_cmd INTO nm inscollist_opt select",
+ /* 278 */ "trigger_cmd ::= DELETE FROM nm where_opt",
+ /* 279 */ "trigger_cmd ::= select",
+ /* 280 */ "expr ::= RAISE LP IGNORE RP",
+ /* 281 */ "expr ::= RAISE LP raisetype COMMA nm RP",
+ /* 282 */ "raisetype ::= ROLLBACK",
+ /* 283 */ "raisetype ::= ABORT",
+ /* 284 */ "raisetype ::= FAIL",
+ /* 285 */ "cmd ::= DROP TRIGGER ifexists fullname",
+ /* 286 */ "cmd ::= ATTACH database_kw_opt expr AS expr key_opt",
+ /* 287 */ "cmd ::= DETACH database_kw_opt expr",
+ /* 288 */ "key_opt ::=",
+ /* 289 */ "key_opt ::= KEY expr",
+ /* 290 */ "database_kw_opt ::= DATABASE",
+ /* 291 */ "database_kw_opt ::=",
+ /* 292 */ "cmd ::= REINDEX",
+ /* 293 */ "cmd ::= REINDEX nm dbnm",
+ /* 294 */ "cmd ::= ANALYZE",
+ /* 295 */ "cmd ::= ANALYZE nm dbnm",
+ /* 296 */ "cmd ::= ALTER TABLE fullname RENAME TO nm",
+ /* 297 */ "cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column",
+ /* 298 */ "add_column_fullname ::= fullname",
+ /* 299 */ "kwcolumn_opt ::=",
+ /* 300 */ "kwcolumn_opt ::= COLUMNKW",
+ /* 301 */ "cmd ::= create_vtab",
+ /* 302 */ "cmd ::= create_vtab LP vtabarglist RP",
+ /* 303 */ "create_vtab ::= CREATE VIRTUAL TABLE nm dbnm USING nm",
+ /* 304 */ "vtabarglist ::= vtabarg",
+ /* 305 */ "vtabarglist ::= vtabarglist COMMA vtabarg",
+ /* 306 */ "vtabarg ::=",
+ /* 307 */ "vtabarg ::= vtabarg vtabargtoken",
+ /* 308 */ "vtabargtoken ::= ANY",
+ /* 309 */ "vtabargtoken ::= lp anylist RP",
+ /* 310 */ "lp ::= LP",
+ /* 311 */ "anylist ::=",
+ /* 312 */ "anylist ::= anylist ANY",
+};
+#endif /* NDEBUG */
+
+
+#if YYSTACKDEPTH<=0
+/*
+** Try to increase the size of the parser stack.
+*/
+static void yyGrowStack(yyParser *p){
+  int newSize;
+  yyStackEntry *pNew;
+
+  newSize = p->yystksz*2 + 100;
+  pNew = realloc(p->yystack, newSize*sizeof(pNew[0]));
+  if( pNew ){
+    p->yystack = pNew;
+    p->yystksz = newSize;
+#ifndef NDEBUG
+    if( yyTraceFILE ){
+      fprintf(yyTraceFILE,"%sStack grows to %d entries!\n",
+              yyTracePrompt, p->yystksz);
+    }
+#endif
+  }
+}
+#endif
+
+/* 
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser.  This pointer is used in subsequent calls
+** to sqlite3Parser and sqlite3ParserFree.
+*/
+SQLITE_PRIVATE void *sqlite3ParserAlloc(void *(*mallocProc)(size_t)){
+  yyParser *pParser;
+  pParser = (yyParser*)(*mallocProc)( (size_t)sizeof(yyParser) );
+  if( pParser ){
+    pParser->yyidx = -1;
+#if YYSTACKDEPTH<=0
+    yyGrowStack(pParser);
+#endif
+  }
+  return pParser;
+}
+
+/* The following function deletes the value associated with a
+** symbol.  The symbol can be either a terminal or nonterminal.
+** "yymajor" is the symbol code, and "yypminor" is a pointer to
+** the value.
+*/
+static void yy_destructor(YYCODETYPE yymajor, YYMINORTYPE *yypminor){
+  switch( yymajor ){
+    /* Here is inserted the actions which take place when a
+    ** terminal or non-terminal is destroyed.  This can happen
+    ** when the symbol is popped from the stack during a
+    ** reduce or during error processing or when a parser is 
+    ** being destroyed before it is finished parsing.
+    **
+    ** Note: during a reduce, the only symbols destroyed are those
+    ** which appear on the RHS of the rule, but which are not used
+    ** inside the C code.
+    */
+    case 155: /* select */
+{
+sqlite3SelectDelete((yypminor->yy219));
+}
+      break;
+    case 169: /* term */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 170: /* expr */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 174: /* idxlist_opt */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 182: /* idxlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 188: /* fullname */
+{
+sqlite3SrcListDelete((yypminor->yy373));
+}
+      break;
+    case 189: /* oneselect */
+{
+sqlite3SelectDelete((yypminor->yy219));
+}
+      break;
+    case 192: /* selcollist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 193: /* from */
+{
+sqlite3SrcListDelete((yypminor->yy373));
+}
+      break;
+    case 194: /* where_opt */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 195: /* groupby_opt */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 196: /* having_opt */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 197: /* orderby_opt */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 199: /* sclp */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 201: /* seltablist */
+{
+sqlite3SrcListDelete((yypminor->yy373));
+}
+      break;
+    case 202: /* stl_prefix */
+{
+sqlite3SrcListDelete((yypminor->yy373));
+}
+      break;
+    case 204: /* on_opt */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 205: /* using_opt */
+{
+sqlite3IdListDelete((yypminor->yy432));
+}
+      break;
+    case 206: /* seltablist_paren */
+{
+sqlite3SelectDelete((yypminor->yy219));
+}
+      break;
+    case 208: /* inscollist */
+{
+sqlite3IdListDelete((yypminor->yy432));
+}
+      break;
+    case 209: /* sortlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 210: /* sortitem */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 211: /* nexprlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 212: /* setlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 214: /* inscollist_opt */
+{
+sqlite3IdListDelete((yypminor->yy432));
+}
+      break;
+    case 215: /* itemlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 216: /* exprlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 218: /* escape */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 221: /* case_operand */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 222: /* case_exprlist */
+{
+sqlite3ExprListDelete((yypminor->yy174));
+}
+      break;
+    case 223: /* case_else */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 231: /* trigger_cmd_list */
+{
+sqlite3DeleteTriggerStep((yypminor->yy243));
+}
+      break;
+    case 233: /* trigger_event */
+{
+sqlite3IdListDelete((yypminor->yy370).b);
+}
+      break;
+    case 235: /* when_clause */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    case 236: /* trigger_cmd */
+{
+sqlite3DeleteTriggerStep((yypminor->yy243));
+}
+      break;
+    case 238: /* key_opt */
+{
+sqlite3ExprDelete((yypminor->yy172));
+}
+      break;
+    default:  break;   /* If no destructor action specified: do nothing */
+  }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+**
+** Return the major token number for the symbol popped.
+*/
+static int yy_pop_parser_stack(yyParser *pParser){
+  YYCODETYPE yymajor;
+  yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];
+
+  if( pParser->yyidx<0 ) return 0;
+#ifndef NDEBUG
+  if( yyTraceFILE && pParser->yyidx>=0 ){
+    fprintf(yyTraceFILE,"%sPopping %s\n",
+      yyTracePrompt,
+      yyTokenName[yytos->major]);
+  }
+#endif
+  yymajor = yytos->major;
+  yy_destructor( yymajor, &yytos->minor);
+  pParser->yyidx--;
+  return yymajor;
+}
+
+/* 
+** Deallocate and destroy a parser.  Destructors are all called for
+** all stack elements before shutting the parser down.
+**
+** Inputs:
+** <ul>
+** <li>  A pointer to the parser.  This should be a pointer
+**       obtained from sqlite3ParserAlloc.
+** <li>  A pointer to a function used to reclaim memory obtained
+**       from malloc.
+** </ul>
+*/
+SQLITE_PRIVATE void sqlite3ParserFree(
+  void *p,                    /* The parser to be deleted */
+  void (*freeProc)(void*)     /* Function used to reclaim memory */
+){
+  yyParser *pParser = (yyParser*)p;
+  if( pParser==0 ) return;
+  while( pParser->yyidx>=0 ) yy_pop_parser_stack(pParser);
+#if YYSTACKDEPTH<=0
+  free(pParser->yystack);
+#endif
+  (*freeProc)((void*)pParser);
+}
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+**
+** If the look-ahead token is YYNOCODE, then check to see if the action is
+** independent of the look-ahead.  If it is, return the action, otherwise
+** return YY_NO_ACTION.
+*/
+static int yy_find_shift_action(
+  yyParser *pParser,        /* The parser */
+  YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+  int stateno = pParser->yystack[pParser->yyidx].stateno;
+ 
+  if( stateno>YY_SHIFT_MAX || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
+    return yy_default[stateno];
+  }
+  assert( iLookAhead!=YYNOCODE );
+  i += iLookAhead;
+  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
+    if( iLookAhead>0 ){
+#ifdef YYFALLBACK
+      int iFallback;            /* Fallback token */
+      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
+             && (iFallback = yyFallback[iLookAhead])!=0 ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
+             yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
+        }
+#endif
+        return yy_find_shift_action(pParser, iFallback);
+      }
+#endif
+#ifdef YYWILDCARD
+      {
+        int j = i - iLookAhead + YYWILDCARD;
+        if( j>=0 && j<YY_SZ_ACTTAB && yy_lookahead[j]==YYWILDCARD ){
+#ifndef NDEBUG
+          if( yyTraceFILE ){
+            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
+               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
+          }
+#endif /* NDEBUG */
+          return yy_action[j];
+        }
+      }
+#endif /* YYWILDCARD */
+    }
+    return yy_default[stateno];
+  }else{
+    return yy_action[i];
+  }
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+**
+** If the look-ahead token is YYNOCODE, then check to see if the action is
+** independent of the look-ahead.  If it is, return the action, otherwise
+** return YY_NO_ACTION.
+*/
+static int yy_find_reduce_action(
+  int stateno,              /* Current state number */
+  YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+#ifdef YYERRORSYMBOL
+  if( stateno>YY_REDUCE_MAX ){
+    return yy_default[stateno];
+  }
+#else
+  assert( stateno<=YY_REDUCE_MAX );
+#endif
+  i = yy_reduce_ofst[stateno];
+  assert( i!=YY_REDUCE_USE_DFLT );
+  assert( iLookAhead!=YYNOCODE );
+  i += iLookAhead;
+#ifdef YYERRORSYMBOL
+  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
+    return yy_default[stateno];
+  }
+#else
+  assert( i>=0 && i<YY_SZ_ACTTAB );
+  assert( yy_lookahead[i]==iLookAhead );
+#endif
+  return yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void yyStackOverflow(yyParser *yypParser, YYMINORTYPE *yypMinor){
+   sqlite3ParserARG_FETCH;
+   yypParser->yyidx--;
+#ifndef NDEBUG
+   if( yyTraceFILE ){
+     fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
+   }
+#endif
+   while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+   /* Here code is inserted which will execute if the parser
+   ** stack every overflows */
+
+  sqlite3ErrorMsg(pParse, "parser stack overflow");
+  pParse->parseError = 1;
+   sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument var */
+}
+
+/*
+** Perform a shift action.
+*/
+static void yy_shift(
+  yyParser *yypParser,          /* The parser to be shifted */
+  int yyNewState,               /* The new state to shift in */
+  int yyMajor,                  /* The major token to shift in */
+  YYMINORTYPE *yypMinor         /* Pointer ot the minor token to shift in */
+){
+  yyStackEntry *yytos;
+  yypParser->yyidx++;
+#if YYSTACKDEPTH>0 
+  if( yypParser->yyidx>=YYSTACKDEPTH ){
+    yyStackOverflow(yypParser, yypMinor);
+    return;
+  }
+#else
+  if( yypParser->yyidx>=yypParser->yystksz ){
+    yyGrowStack(yypParser);
+    if( yypParser->yyidx>=yypParser->yystksz ){
+      yyStackOverflow(yypParser, yypMinor);
+      return;
+    }
+  }
+#endif
+  yytos = &yypParser->yystack[yypParser->yyidx];
+  yytos->stateno = yyNewState;
+  yytos->major = yyMajor;
+  yytos->minor = *yypMinor;
+#ifndef NDEBUG
+  if( yyTraceFILE && yypParser->yyidx>0 ){
+    int i;
+    fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState);
+    fprintf(yyTraceFILE,"%sStack:",yyTracePrompt);
+    for(i=1; i<=yypParser->yyidx; i++)
+      fprintf(yyTraceFILE," %s",yyTokenName[yypParser->yystack[i].major]);
+    fprintf(yyTraceFILE,"\n");
+  }
+#endif
+}
+
+/* The following table contains information about every rule that
+** is used during the reduce.
+*/
+static const struct {
+  YYCODETYPE lhs;         /* Symbol on the left-hand side of the rule */
+  unsigned char nrhs;     /* Number of right-hand side symbols in the rule */
+} yyRuleInfo[] = {
+  { 139, 1 },
+  { 140, 2 },
+  { 140, 1 },
+  { 142, 1 },
+  { 141, 1 },
+  { 141, 3 },
+  { 144, 0 },
+  { 144, 1 },
+  { 144, 3 },
+  { 143, 3 },
+  { 146, 0 },
+  { 146, 1 },
+  { 146, 2 },
+  { 145, 0 },
+  { 145, 1 },
+  { 145, 1 },
+  { 145, 1 },
+  { 143, 2 },
+  { 143, 2 },
+  { 143, 2 },
+  { 143, 2 },
+  { 148, 6 },
+  { 151, 0 },
+  { 151, 3 },
+  { 150, 1 },
+  { 150, 0 },
+  { 149, 4 },
+  { 149, 2 },
+  { 153, 3 },
+  { 153, 1 },
+  { 156, 3 },
+  { 157, 1 },
+  { 160, 1 },
+  { 161, 1 },
+  { 147, 1 },
+  { 147, 1 },
+  { 147, 1 },
+  { 158, 0 },
+  { 158, 1 },
+  { 162, 1 },
+  { 162, 4 },
+  { 162, 6 },
+  { 163, 1 },
+  { 163, 2 },
+  { 164, 1 },
+  { 164, 1 },
+  { 159, 2 },
+  { 159, 0 },
+  { 167, 3 },
+  { 167, 1 },
+  { 168, 2 },
+  { 168, 4 },
+  { 168, 3 },
+  { 168, 3 },
+  { 168, 2 },
+  { 168, 2 },
+  { 168, 3 },
+  { 168, 5 },
+  { 168, 2 },
+  { 168, 4 },
+  { 168, 4 },
+  { 168, 1 },
+  { 168, 2 },
+  { 173, 0 },
+  { 173, 1 },
+  { 175, 0 },
+  { 175, 2 },
+  { 177, 2 },
+  { 177, 3 },
+  { 177, 3 },
+  { 177, 3 },
+  { 178, 2 },
+  { 178, 2 },
+  { 178, 1 },
+  { 178, 1 },
+  { 176, 3 },
+  { 176, 2 },
+  { 179, 0 },
+  { 179, 2 },
+  { 179, 2 },
+  { 154, 0 },
+  { 154, 2 },
+  { 180, 3 },
+  { 180, 2 },
+  { 180, 1 },
+  { 181, 2 },
+  { 181, 7 },
+  { 181, 5 },
+  { 181, 5 },
+  { 181, 10 },
+  { 183, 0 },
+  { 183, 1 },
+  { 171, 0 },
+  { 171, 3 },
+  { 184, 0 },
+  { 184, 2 },
+  { 185, 1 },
+  { 185, 1 },
+  { 185, 1 },
+  { 143, 4 },
+  { 187, 2 },
+  { 187, 0 },
+  { 143, 8 },
+  { 143, 4 },
+  { 143, 1 },
+  { 155, 1 },
+  { 155, 3 },
+  { 190, 1 },
+  { 190, 2 },
+  { 190, 1 },
+  { 189, 9 },
+  { 191, 1 },
+  { 191, 1 },
+  { 191, 0 },
+  { 199, 2 },
+  { 199, 0 },
+  { 192, 3 },
+  { 192, 2 },
+  { 192, 4 },
+  { 200, 2 },
+  { 200, 1 },
+  { 200, 0 },
+  { 193, 0 },
+  { 193, 2 },
+  { 202, 2 },
+  { 202, 0 },
+  { 201, 6 },
+  { 201, 7 },
+  { 206, 1 },
+  { 206, 1 },
+  { 152, 0 },
+  { 152, 2 },
+  { 188, 2 },
+  { 203, 1 },
+  { 203, 2 },
+  { 203, 3 },
+  { 203, 4 },
+  { 204, 2 },
+  { 204, 0 },
+  { 205, 4 },
+  { 205, 0 },
+  { 197, 0 },
+  { 197, 3 },
+  { 209, 4 },
+  { 209, 2 },
+  { 210, 1 },
+  { 172, 1 },
+  { 172, 1 },
+  { 172, 0 },
+  { 195, 0 },
+  { 195, 3 },
+  { 196, 0 },
+  { 196, 2 },
+  { 198, 0 },
+  { 198, 2 },
+  { 198, 4 },
+  { 198, 4 },
+  { 143, 4 },
+  { 194, 0 },
+  { 194, 2 },
+  { 143, 6 },
+  { 212, 5 },
+  { 212, 3 },
+  { 143, 8 },
+  { 143, 5 },
+  { 143, 6 },
+  { 213, 2 },
+  { 213, 1 },
+  { 215, 3 },
+  { 215, 1 },
+  { 214, 0 },
+  { 214, 3 },
+  { 208, 3 },
+  { 208, 1 },
+  { 170, 1 },
+  { 170, 3 },
+  { 169, 1 },
+  { 170, 1 },
+  { 170, 1 },
+  { 170, 3 },
+  { 170, 5 },
+  { 169, 1 },
+  { 169, 1 },
+  { 170, 1 },
+  { 170, 1 },
+  { 170, 3 },
+  { 170, 6 },
+  { 170, 5 },
+  { 170, 4 },
+  { 169, 1 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 3 },
+  { 217, 1 },
+  { 217, 2 },
+  { 217, 1 },
+  { 217, 2 },
+  { 218, 2 },
+  { 218, 0 },
+  { 170, 4 },
+  { 170, 2 },
+  { 170, 3 },
+  { 170, 3 },
+  { 170, 4 },
+  { 170, 2 },
+  { 170, 2 },
+  { 170, 2 },
+  { 170, 2 },
+  { 219, 1 },
+  { 219, 2 },
+  { 170, 5 },
+  { 220, 1 },
+  { 220, 2 },
+  { 170, 5 },
+  { 170, 3 },
+  { 170, 5 },
+  { 170, 4 },
+  { 170, 4 },
+  { 170, 5 },
+  { 222, 5 },
+  { 222, 4 },
+  { 223, 2 },
+  { 223, 0 },
+  { 221, 1 },
+  { 221, 0 },
+  { 216, 1 },
+  { 216, 0 },
+  { 211, 3 },
+  { 211, 1 },
+  { 143, 11 },
+  { 224, 1 },
+  { 224, 0 },
+  { 174, 0 },
+  { 174, 3 },
+  { 182, 5 },
+  { 182, 3 },
+  { 225, 1 },
+  { 226, 0 },
+  { 226, 2 },
+  { 143, 4 },
+  { 143, 1 },
+  { 143, 2 },
+  { 143, 5 },
+  { 143, 5 },
+  { 143, 5 },
+  { 143, 5 },
+  { 143, 6 },
+  { 143, 3 },
+  { 227, 1 },
+  { 227, 1 },
+  { 165, 2 },
+  { 166, 2 },
+  { 229, 1 },
+  { 228, 1 },
+  { 228, 0 },
+  { 143, 5 },
+  { 230, 11 },
+  { 232, 1 },
+  { 232, 1 },
+  { 232, 2 },
+  { 232, 0 },
+  { 233, 1 },
+  { 233, 1 },
+  { 233, 3 },
+  { 234, 0 },
+  { 234, 3 },
+  { 235, 0 },
+  { 235, 2 },
+  { 231, 3 },
+  { 231, 0 },
+  { 236, 6 },
+  { 236, 8 },
+  { 236, 5 },
+  { 236, 4 },
+  { 236, 1 },
+  { 170, 4 },
+  { 170, 6 },
+  { 186, 1 },
+  { 186, 1 },
+  { 186, 1 },
+  { 143, 4 },
+  { 143, 6 },
+  { 143, 3 },
+  { 238, 0 },
+  { 238, 2 },
+  { 237, 1 },
+  { 237, 0 },
+  { 143, 1 },
+  { 143, 3 },
+  { 143, 1 },
+  { 143, 3 },
+  { 143, 6 },
+  { 143, 6 },
+  { 239, 1 },
+  { 240, 0 },
+  { 240, 1 },
+  { 143, 1 },
+  { 143, 4 },
+  { 241, 7 },
+  { 242, 1 },
+  { 242, 3 },
+  { 243, 0 },
+  { 243, 2 },
+  { 244, 1 },
+  { 244, 3 },
+  { 245, 1 },
+  { 246, 0 },
+  { 246, 2 },
+};
+
+static void yy_accept(yyParser*);  /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+*/
+static void yy_reduce(
+  yyParser *yypParser,         /* The parser */
+  int yyruleno                 /* Number of the rule by which to reduce */
+){
+  int yygoto;                     /* The next state */
+  int yyact;                      /* The next action */
+  YYMINORTYPE yygotominor;        /* The LHS of the rule reduced */
+  yyStackEntry *yymsp;            /* The top of the parser's stack */
+  int yysize;                     /* Amount to pop the stack */
+  sqlite3ParserARG_FETCH;
+  yymsp = &yypParser->yystack[yypParser->yyidx];
+#ifndef NDEBUG
+  if( yyTraceFILE && yyruleno>=0 
+        && yyruleno<(int)(sizeof(yyRuleName)/sizeof(yyRuleName[0])) ){
+    fprintf(yyTraceFILE, "%sReduce [%s].\n", yyTracePrompt,
+      yyRuleName[yyruleno]);
+  }
+#endif /* NDEBUG */
+
+  /* Silence complaints from purify about yygotominor being uninitialized
+  ** in some cases when it is copied into the stack after the following
+  ** switch.  yygotominor is uninitialized when a rule reduces that does
+  ** not set the value of its left-hand side nonterminal.  Leaving the
+  ** value of the nonterminal uninitialized is utterly harmless as long
+  ** as the value is never used.  So really the only thing this code
+  ** accomplishes is to quieten purify.  
+  **
+  ** 2007-01-16:  The wireshark project (www.wireshark.org) reports that
+  ** without this code, their parser segfaults.  I'm not sure what there
+  ** parser is doing to make this happen.  This is the second bug report
+  ** from wireshark this week.  Clearly they are stressing Lemon in ways
+  ** that it has not been previously stressed...  (SQLite ticket #2172)
+  */
+  /*memset(&yygotominor, 0, sizeof(yygotominor));*/
+  yygotominor = yyzerominor;
+
+
+  switch( yyruleno ){
+  /* Beginning here are the reduction cases.  A typical example
+  ** follows:
+  **   case 0:
+  **  #line <lineno> <grammarfile>
+  **     { ... }           // User supplied code
+  **  #line <lineno> <thisfile>
+  **     break;
+  */
+      case 0: /* input ::= cmdlist */
+      case 1: /* cmdlist ::= cmdlist ecmd */
+      case 2: /* cmdlist ::= ecmd */
+      case 4: /* ecmd ::= SEMI */
+      case 5: /* ecmd ::= explain cmdx SEMI */
+      case 10: /* trans_opt ::= */
+      case 11: /* trans_opt ::= TRANSACTION */
+      case 12: /* trans_opt ::= TRANSACTION nm */
+      case 20: /* cmd ::= create_table create_table_args */
+      case 28: /* columnlist ::= columnlist COMMA column */
+      case 29: /* columnlist ::= column */
+      case 37: /* type ::= */
+      case 44: /* signed ::= plus_num */
+      case 45: /* signed ::= minus_num */
+      case 46: /* carglist ::= carglist carg */
+      case 47: /* carglist ::= */
+      case 48: /* carg ::= CONSTRAINT nm ccons */
+      case 49: /* carg ::= ccons */
+      case 55: /* ccons ::= NULL onconf */
+      case 82: /* conslist ::= conslist COMMA tcons */
+      case 83: /* conslist ::= conslist tcons */
+      case 84: /* conslist ::= tcons */
+      case 85: /* tcons ::= CONSTRAINT nm */
+      case 258: /* plus_opt ::= PLUS */
+      case 259: /* plus_opt ::= */
+      case 269: /* foreach_clause ::= */
+      case 270: /* foreach_clause ::= FOR EACH ROW */
+      case 290: /* database_kw_opt ::= DATABASE */
+      case 291: /* database_kw_opt ::= */
+      case 299: /* kwcolumn_opt ::= */
+      case 300: /* kwcolumn_opt ::= COLUMNKW */
+      case 304: /* vtabarglist ::= vtabarg */
+      case 305: /* vtabarglist ::= vtabarglist COMMA vtabarg */
+      case 307: /* vtabarg ::= vtabarg vtabargtoken */
+      case 311: /* anylist ::= */
+{
+}
+        break;
+      case 3: /* cmdx ::= cmd */
+{ sqlite3FinishCoding(pParse); }
+        break;
+      case 6: /* explain ::= */
+{ sqlite3BeginParse(pParse, 0); }
+        break;
+      case 7: /* explain ::= EXPLAIN */
+{ sqlite3BeginParse(pParse, 1); }
+        break;
+      case 8: /* explain ::= EXPLAIN QUERY PLAN */
+{ sqlite3BeginParse(pParse, 2); }
+        break;
+      case 9: /* cmd ::= BEGIN transtype trans_opt */
+{sqlite3BeginTransaction(pParse, yymsp[-1].minor.yy46);}
+        break;
+      case 13: /* transtype ::= */
+{yygotominor.yy46 = TK_DEFERRED;}
+        break;
+      case 14: /* transtype ::= DEFERRED */
+      case 15: /* transtype ::= IMMEDIATE */
+      case 16: /* transtype ::= EXCLUSIVE */
+      case 107: /* multiselect_op ::= UNION */
+      case 109: /* multiselect_op ::= EXCEPT|INTERSECT */
+{yygotominor.yy46 = yymsp[0].major;}
+        break;
+      case 17: /* cmd ::= COMMIT trans_opt */
+      case 18: /* cmd ::= END trans_opt */
+{sqlite3CommitTransaction(pParse);}
+        break;
+      case 19: /* cmd ::= ROLLBACK trans_opt */
+{sqlite3RollbackTransaction(pParse);}
+        break;
+      case 21: /* create_table ::= CREATE temp TABLE ifnotexists nm dbnm */
+{
+   sqlite3StartTable(pParse,&yymsp[-1].minor.yy410,&yymsp[0].minor.yy410,yymsp[-4].minor.yy46,0,0,yymsp[-2].minor.yy46);
+}
+        break;
+      case 22: /* ifnotexists ::= */
+      case 25: /* temp ::= */
+      case 63: /* autoinc ::= */
+      case 77: /* init_deferred_pred_opt ::= */
+      case 79: /* init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+      case 90: /* defer_subclause_opt ::= */
+      case 101: /* ifexists ::= */
+      case 112: /* distinct ::= ALL */
+      case 113: /* distinct ::= */
+      case 213: /* between_op ::= BETWEEN */
+      case 216: /* in_op ::= IN */
+{yygotominor.yy46 = 0;}
+        break;
+      case 23: /* ifnotexists ::= IF NOT EXISTS */
+      case 24: /* temp ::= TEMP */
+      case 64: /* autoinc ::= AUTOINCR */
+      case 78: /* init_deferred_pred_opt ::= INITIALLY DEFERRED */
+      case 100: /* ifexists ::= IF EXISTS */
+      case 111: /* distinct ::= DISTINCT */
+      case 214: /* between_op ::= NOT BETWEEN */
+      case 217: /* in_op ::= NOT IN */
+{yygotominor.yy46 = 1;}
+        break;
+      case 26: /* create_table_args ::= LP columnlist conslist_opt RP */
+{
+  sqlite3EndTable(pParse,&yymsp[-1].minor.yy410,&yymsp[0].minor.yy0,0);
+}
+        break;
+      case 27: /* create_table_args ::= AS select */
+{
+  sqlite3EndTable(pParse,0,0,yymsp[0].minor.yy219);
+  sqlite3SelectDelete(yymsp[0].minor.yy219);
+}
+        break;
+      case 30: /* column ::= columnid type carglist */
+{
+  yygotominor.yy410.z = yymsp[-2].minor.yy410.z;
+  yygotominor.yy410.n = (pParse->sLastToken.z-yymsp[-2].minor.yy410.z) + pParse->sLastToken.n;
+}
+        break;
+      case 31: /* columnid ::= nm */
+{
+  sqlite3AddColumn(pParse,&yymsp[0].minor.yy410);
+  yygotominor.yy410 = yymsp[0].minor.yy410;
+}
+        break;
+      case 32: /* id ::= ID */
+      case 33: /* ids ::= ID|STRING */
+      case 34: /* nm ::= ID */
+      case 35: /* nm ::= STRING */
+      case 36: /* nm ::= JOIN_KW */
+      case 257: /* number ::= INTEGER|FLOAT */
+{yygotominor.yy410 = yymsp[0].minor.yy0;}
+        break;
+      case 38: /* type ::= typetoken */
+{sqlite3AddColumnType(pParse,&yymsp[0].minor.yy410);}
+        break;
+      case 39: /* typetoken ::= typename */
+      case 42: /* typename ::= ids */
+      case 119: /* as ::= AS nm */
+      case 120: /* as ::= ids */
+      case 131: /* dbnm ::= DOT nm */
+      case 241: /* idxitem ::= nm */
+      case 243: /* collate ::= COLLATE ids */
+      case 253: /* nmnum ::= plus_num */
+      case 254: /* nmnum ::= nm */
+      case 255: /* plus_num ::= plus_opt number */
+      case 256: /* minus_num ::= MINUS number */
+{yygotominor.yy410 = yymsp[0].minor.yy410;}
+        break;
+      case 40: /* typetoken ::= typename LP signed RP */
+{
+  yygotominor.yy410.z = yymsp[-3].minor.yy410.z;
+  yygotominor.yy410.n = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-3].minor.yy410.z;
+}
+        break;
+      case 41: /* typetoken ::= typename LP signed COMMA signed RP */
+{
+  yygotominor.yy410.z = yymsp[-5].minor.yy410.z;
+  yygotominor.yy410.n = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-5].minor.yy410.z;
+}
+        break;
+      case 43: /* typename ::= typename ids */
+{yygotominor.yy410.z=yymsp[-1].minor.yy410.z; yygotominor.yy410.n=yymsp[0].minor.yy410.n+(yymsp[0].minor.yy410.z-yymsp[-1].minor.yy410.z);}
+        break;
+      case 50: /* ccons ::= DEFAULT term */
+      case 52: /* ccons ::= DEFAULT PLUS term */
+{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy172);}
+        break;
+      case 51: /* ccons ::= DEFAULT LP expr RP */
+{sqlite3AddDefaultValue(pParse,yymsp[-1].minor.yy172);}
+        break;
+      case 53: /* ccons ::= DEFAULT MINUS term */
+{
+  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy172, 0, 0);
+  sqlite3AddDefaultValue(pParse,p);
+}
+        break;
+      case 54: /* ccons ::= DEFAULT id */
+{
+  Expr *p = sqlite3PExpr(pParse, TK_STRING, 0, 0, &yymsp[0].minor.yy410);
+  sqlite3AddDefaultValue(pParse,p);
+}
+        break;
+      case 56: /* ccons ::= NOT NULL onconf */
+{sqlite3AddNotNull(pParse, yymsp[0].minor.yy46);}
+        break;
+      case 57: /* ccons ::= PRIMARY KEY sortorder onconf autoinc */
+{sqlite3AddPrimaryKey(pParse,0,yymsp[-1].minor.yy46,yymsp[0].minor.yy46,yymsp[-2].minor.yy46);}
+        break;
+      case 58: /* ccons ::= UNIQUE onconf */
+{sqlite3CreateIndex(pParse,0,0,0,0,yymsp[0].minor.yy46,0,0,0,0);}
+        break;
+      case 59: /* ccons ::= CHECK LP expr RP */
+{sqlite3AddCheckConstraint(pParse,yymsp[-1].minor.yy172);}
+        break;
+      case 60: /* ccons ::= REFERENCES nm idxlist_opt refargs */
+{sqlite3CreateForeignKey(pParse,0,&yymsp[-2].minor.yy410,yymsp[-1].minor.yy174,yymsp[0].minor.yy46);}
+        break;
+      case 61: /* ccons ::= defer_subclause */
+{sqlite3DeferForeignKey(pParse,yymsp[0].minor.yy46);}
+        break;
+      case 62: /* ccons ::= COLLATE ids */
+{sqlite3AddCollateType(pParse, &yymsp[0].minor.yy410);}
+        break;
+      case 65: /* refargs ::= */
+{ yygotominor.yy46 = OE_Restrict * 0x010101; }
+        break;
+      case 66: /* refargs ::= refargs refarg */
+{ yygotominor.yy46 = (yymsp[-1].minor.yy46 & yymsp[0].minor.yy405.mask) | yymsp[0].minor.yy405.value; }
+        break;
+      case 67: /* refarg ::= MATCH nm */
+{ yygotominor.yy405.value = 0;     yygotominor.yy405.mask = 0x000000; }
+        break;
+      case 68: /* refarg ::= ON DELETE refact */
+{ yygotominor.yy405.value = yymsp[0].minor.yy46;     yygotominor.yy405.mask = 0x0000ff; }
+        break;
+      case 69: /* refarg ::= ON UPDATE refact */
+{ yygotominor.yy405.value = yymsp[0].minor.yy46<<8;  yygotominor.yy405.mask = 0x00ff00; }
+        break;
+      case 70: /* refarg ::= ON INSERT refact */
+{ yygotominor.yy405.value = yymsp[0].minor.yy46<<16; yygotominor.yy405.mask = 0xff0000; }
+        break;
+      case 71: /* refact ::= SET NULL */
+{ yygotominor.yy46 = OE_SetNull; }
+        break;
+      case 72: /* refact ::= SET DEFAULT */
+{ yygotominor.yy46 = OE_SetDflt; }
+        break;
+      case 73: /* refact ::= CASCADE */
+{ yygotominor.yy46 = OE_Cascade; }
+        break;
+      case 74: /* refact ::= RESTRICT */
+{ yygotominor.yy46 = OE_Restrict; }
+        break;
+      case 75: /* defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+      case 76: /* defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+      case 91: /* defer_subclause_opt ::= defer_subclause */
+      case 93: /* onconf ::= ON CONFLICT resolvetype */
+      case 95: /* orconf ::= OR resolvetype */
+      case 96: /* resolvetype ::= raisetype */
+      case 166: /* insert_cmd ::= INSERT orconf */
+{yygotominor.yy46 = yymsp[0].minor.yy46;}
+        break;
+      case 80: /* conslist_opt ::= */
+{yygotominor.yy410.n = 0; yygotominor.yy410.z = 0;}
+        break;
+      case 81: /* conslist_opt ::= COMMA conslist */
+{yygotominor.yy410 = yymsp[-1].minor.yy0;}
+        break;
+      case 86: /* tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf */
+{sqlite3AddPrimaryKey(pParse,yymsp[-3].minor.yy174,yymsp[0].minor.yy46,yymsp[-2].minor.yy46,0);}
+        break;
+      case 87: /* tcons ::= UNIQUE LP idxlist RP onconf */
+{sqlite3CreateIndex(pParse,0,0,0,yymsp[-2].minor.yy174,yymsp[0].minor.yy46,0,0,0,0);}
+        break;
+      case 88: /* tcons ::= CHECK LP expr RP onconf */
+{sqlite3AddCheckConstraint(pParse,yymsp[-2].minor.yy172);}
+        break;
+      case 89: /* tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt */
+{
+    sqlite3CreateForeignKey(pParse, yymsp[-6].minor.yy174, &yymsp[-3].minor.yy410, yymsp[-2].minor.yy174, yymsp[-1].minor.yy46);
+    sqlite3DeferForeignKey(pParse, yymsp[0].minor.yy46);
+}
+        break;
+      case 92: /* onconf ::= */
+      case 94: /* orconf ::= */
+{yygotominor.yy46 = OE_Default;}
+        break;
+      case 97: /* resolvetype ::= IGNORE */
+{yygotominor.yy46 = OE_Ignore;}
+        break;
+      case 98: /* resolvetype ::= REPLACE */
+      case 167: /* insert_cmd ::= REPLACE */
+{yygotominor.yy46 = OE_Replace;}
+        break;
+      case 99: /* cmd ::= DROP TABLE ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy373, 0, yymsp[-1].minor.yy46);
+}
+        break;
+      case 102: /* cmd ::= CREATE temp VIEW ifnotexists nm dbnm AS select */
+{
+  sqlite3CreateView(pParse, &yymsp[-7].minor.yy0, &yymsp[-3].minor.yy410, &yymsp[-2].minor.yy410, yymsp[0].minor.yy219, yymsp[-6].minor.yy46, yymsp[-4].minor.yy46);
+}
+        break;
+      case 103: /* cmd ::= DROP VIEW ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy373, 1, yymsp[-1].minor.yy46);
+}
+        break;
+      case 104: /* cmd ::= select */
+{
+  SelectDest dest = {SRT_Callback, 0, 0, 0, 0};
+  sqlite3Select(pParse, yymsp[0].minor.yy219, &dest, 0, 0, 0, 0);
+  sqlite3SelectDelete(yymsp[0].minor.yy219);
+}
+        break;
+      case 105: /* select ::= oneselect */
+      case 128: /* seltablist_paren ::= select */
+{yygotominor.yy219 = yymsp[0].minor.yy219;}
+        break;
+      case 106: /* select ::= select multiselect_op oneselect */
+{
+  if( yymsp[0].minor.yy219 ){
+    yymsp[0].minor.yy219->op = yymsp[-1].minor.yy46;
+    yymsp[0].minor.yy219->pPrior = yymsp[-2].minor.yy219;
+  }else{
+    sqlite3SelectDelete(yymsp[-2].minor.yy219);
+  }
+  yygotominor.yy219 = yymsp[0].minor.yy219;
+}
+        break;
+      case 108: /* multiselect_op ::= UNION ALL */
+{yygotominor.yy46 = TK_ALL;}
+        break;
+      case 110: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+{
+  yygotominor.yy219 = sqlite3SelectNew(pParse,yymsp[-6].minor.yy174,yymsp[-5].minor.yy373,yymsp[-4].minor.yy172,yymsp[-3].minor.yy174,yymsp[-2].minor.yy172,yymsp[-1].minor.yy174,yymsp[-7].minor.yy46,yymsp[0].minor.yy234.pLimit,yymsp[0].minor.yy234.pOffset);
+}
+        break;
+      case 114: /* sclp ::= selcollist COMMA */
+      case 238: /* idxlist_opt ::= LP idxlist RP */
+{yygotominor.yy174 = yymsp[-1].minor.yy174;}
+        break;
+      case 115: /* sclp ::= */
+      case 141: /* orderby_opt ::= */
+      case 149: /* groupby_opt ::= */
+      case 231: /* exprlist ::= */
+      case 237: /* idxlist_opt ::= */
+{yygotominor.yy174 = 0;}
+        break;
+      case 116: /* selcollist ::= sclp expr as */
+{
+   yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy174,yymsp[-1].minor.yy172,yymsp[0].minor.yy410.n?&yymsp[0].minor.yy410:0);
+}
+        break;
+      case 117: /* selcollist ::= sclp STAR */
+{
+  Expr *p = sqlite3PExpr(pParse, TK_ALL, 0, 0, 0);
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse, yymsp[-1].minor.yy174, p, 0);
+}
+        break;
+      case 118: /* selcollist ::= sclp nm DOT STAR */
+{
+  Expr *pRight = sqlite3PExpr(pParse, TK_ALL, 0, 0, 0);
+  Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy410);
+  Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy174, pDot, 0);
+}
+        break;
+      case 121: /* as ::= */
+{yygotominor.yy410.n = 0;}
+        break;
+      case 122: /* from ::= */
+{yygotominor.yy373 = sqlite3DbMallocZero(pParse->db, sizeof(*yygotominor.yy373));}
+        break;
+      case 123: /* from ::= FROM seltablist */
+{
+  yygotominor.yy373 = yymsp[0].minor.yy373;
+  sqlite3SrcListShiftJoinType(yygotominor.yy373);
+}
+        break;
+      case 124: /* stl_prefix ::= seltablist joinop */
+{
+   yygotominor.yy373 = yymsp[-1].minor.yy373;
+   if( yygotominor.yy373 && yygotominor.yy373->nSrc>0 ) yygotominor.yy373->a[yygotominor.yy373->nSrc-1].jointype = yymsp[0].minor.yy46;
+}
+        break;
+      case 125: /* stl_prefix ::= */
+{yygotominor.yy373 = 0;}
+        break;
+      case 126: /* seltablist ::= stl_prefix nm dbnm as on_opt using_opt */
+{
+  yygotominor.yy373 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy373,&yymsp[-4].minor.yy410,&yymsp[-3].minor.yy410,&yymsp[-2].minor.yy410,0,yymsp[-1].minor.yy172,yymsp[0].minor.yy432);
+}
+        break;
+      case 127: /* seltablist ::= stl_prefix LP seltablist_paren RP as on_opt using_opt */
+{
+    yygotominor.yy373 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-6].minor.yy373,0,0,&yymsp[-2].minor.yy410,yymsp[-4].minor.yy219,yymsp[-1].minor.yy172,yymsp[0].minor.yy432);
+  }
+        break;
+      case 129: /* seltablist_paren ::= seltablist */
+{
+     sqlite3SrcListShiftJoinType(yymsp[0].minor.yy373);
+     yygotominor.yy219 = sqlite3SelectNew(pParse,0,yymsp[0].minor.yy373,0,0,0,0,0,0,0);
+  }
+        break;
+      case 130: /* dbnm ::= */
+{yygotominor.yy410.z=0; yygotominor.yy410.n=0;}
+        break;
+      case 132: /* fullname ::= nm dbnm */
+{yygotominor.yy373 = sqlite3SrcListAppend(pParse->db,0,&yymsp[-1].minor.yy410,&yymsp[0].minor.yy410);}
+        break;
+      case 133: /* joinop ::= COMMA|JOIN */
+{ yygotominor.yy46 = JT_INNER; }
+        break;
+      case 134: /* joinop ::= JOIN_KW JOIN */
+{ yygotominor.yy46 = sqlite3JoinType(pParse,&yymsp[-1].minor.yy0,0,0); }
+        break;
+      case 135: /* joinop ::= JOIN_KW nm JOIN */
+{ yygotominor.yy46 = sqlite3JoinType(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy410,0); }
+        break;
+      case 136: /* joinop ::= JOIN_KW nm nm JOIN */
+{ yygotominor.yy46 = sqlite3JoinType(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy410,&yymsp[-1].minor.yy410); }
+        break;
+      case 137: /* on_opt ::= ON expr */
+      case 145: /* sortitem ::= expr */
+      case 152: /* having_opt ::= HAVING expr */
+      case 159: /* where_opt ::= WHERE expr */
+      case 174: /* expr ::= term */
+      case 202: /* escape ::= ESCAPE expr */
+      case 226: /* case_else ::= ELSE expr */
+      case 228: /* case_operand ::= expr */
+{yygotominor.yy172 = yymsp[0].minor.yy172;}
+        break;
+      case 138: /* on_opt ::= */
+      case 151: /* having_opt ::= */
+      case 158: /* where_opt ::= */
+      case 203: /* escape ::= */
+      case 227: /* case_else ::= */
+      case 229: /* case_operand ::= */
+{yygotominor.yy172 = 0;}
+        break;
+      case 139: /* using_opt ::= USING LP inscollist RP */
+      case 171: /* inscollist_opt ::= LP inscollist RP */
+{yygotominor.yy432 = yymsp[-1].minor.yy432;}
+        break;
+      case 140: /* using_opt ::= */
+      case 170: /* inscollist_opt ::= */
+{yygotominor.yy432 = 0;}
+        break;
+      case 142: /* orderby_opt ::= ORDER BY sortlist */
+      case 150: /* groupby_opt ::= GROUP BY nexprlist */
+      case 230: /* exprlist ::= nexprlist */
+{yygotominor.yy174 = yymsp[0].minor.yy174;}
+        break;
+      case 143: /* sortlist ::= sortlist COMMA sortitem sortorder */
+{
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy174,yymsp[-1].minor.yy172,0);
+  if( yygotominor.yy174 ) yygotominor.yy174->a[yygotominor.yy174->nExpr-1].sortOrder = yymsp[0].minor.yy46;
+}
+        break;
+      case 144: /* sortlist ::= sortitem sortorder */
+{
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,0,yymsp[-1].minor.yy172,0);
+  if( yygotominor.yy174 && yygotominor.yy174->a ) yygotominor.yy174->a[0].sortOrder = yymsp[0].minor.yy46;
+}
+        break;
+      case 146: /* sortorder ::= ASC */
+      case 148: /* sortorder ::= */
+{yygotominor.yy46 = SQLITE_SO_ASC;}
+        break;
+      case 147: /* sortorder ::= DESC */
+{yygotominor.yy46 = SQLITE_SO_DESC;}
+        break;
+      case 153: /* limit_opt ::= */
+{yygotominor.yy234.pLimit = 0; yygotominor.yy234.pOffset = 0;}
+        break;
+      case 154: /* limit_opt ::= LIMIT expr */
+{yygotominor.yy234.pLimit = yymsp[0].minor.yy172; yygotominor.yy234.pOffset = 0;}
+        break;
+      case 155: /* limit_opt ::= LIMIT expr OFFSET expr */
+{yygotominor.yy234.pLimit = yymsp[-2].minor.yy172; yygotominor.yy234.pOffset = yymsp[0].minor.yy172;}
+        break;
+      case 156: /* limit_opt ::= LIMIT expr COMMA expr */
+{yygotominor.yy234.pOffset = yymsp[-2].minor.yy172; yygotominor.yy234.pLimit = yymsp[0].minor.yy172;}
+        break;
+      case 157: /* cmd ::= DELETE FROM fullname where_opt */
+{sqlite3DeleteFrom(pParse,yymsp[-1].minor.yy373,yymsp[0].minor.yy172);}
+        break;
+      case 160: /* cmd ::= UPDATE orconf fullname SET setlist where_opt */
+{
+  sqlite3ExprListCheckLength(pParse,yymsp[-1].minor.yy174,"set list"); 
+  sqlite3Update(pParse,yymsp[-3].minor.yy373,yymsp[-1].minor.yy174,yymsp[0].minor.yy172,yymsp[-4].minor.yy46);
+}
+        break;
+      case 161: /* setlist ::= setlist COMMA nm EQ expr */
+{yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy174,yymsp[0].minor.yy172,&yymsp[-2].minor.yy410);}
+        break;
+      case 162: /* setlist ::= nm EQ expr */
+{yygotominor.yy174 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy172,&yymsp[-2].minor.yy410);}
+        break;
+      case 163: /* cmd ::= insert_cmd INTO fullname inscollist_opt VALUES LP itemlist RP */
+{sqlite3Insert(pParse, yymsp[-5].minor.yy373, yymsp[-1].minor.yy174, 0, yymsp[-4].minor.yy432, yymsp[-7].minor.yy46);}
+        break;
+      case 164: /* cmd ::= insert_cmd INTO fullname inscollist_opt select */
+{sqlite3Insert(pParse, yymsp[-2].minor.yy373, 0, yymsp[0].minor.yy219, yymsp[-1].minor.yy432, yymsp[-4].minor.yy46);}
+        break;
+      case 165: /* cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES */
+{sqlite3Insert(pParse, yymsp[-3].minor.yy373, 0, 0, yymsp[-2].minor.yy432, yymsp[-5].minor.yy46);}
+        break;
+      case 168: /* itemlist ::= itemlist COMMA expr */
+      case 232: /* nexprlist ::= nexprlist COMMA expr */
+{yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy174,yymsp[0].minor.yy172,0);}
+        break;
+      case 169: /* itemlist ::= expr */
+      case 233: /* nexprlist ::= expr */
+{yygotominor.yy174 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy172,0);}
+        break;
+      case 172: /* inscollist ::= inscollist COMMA nm */
+{yygotominor.yy432 = sqlite3IdListAppend(pParse->db,yymsp[-2].minor.yy432,&yymsp[0].minor.yy410);}
+        break;
+      case 173: /* inscollist ::= nm */
+{yygotominor.yy432 = sqlite3IdListAppend(pParse->db,0,&yymsp[0].minor.yy410);}
+        break;
+      case 175: /* expr ::= LP expr RP */
+{yygotominor.yy172 = yymsp[-1].minor.yy172; sqlite3ExprSpan(yygotominor.yy172,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0); }
+        break;
+      case 176: /* term ::= NULL */
+      case 181: /* term ::= INTEGER|FLOAT|BLOB */
+      case 182: /* term ::= STRING */
+{yygotominor.yy172 = sqlite3PExpr(pParse, yymsp[0].major, 0, 0, &yymsp[0].minor.yy0);}
+        break;
+      case 177: /* expr ::= ID */
+      case 178: /* expr ::= JOIN_KW */
+{yygotominor.yy172 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy0);}
+        break;
+      case 179: /* expr ::= nm DOT nm */
+{
+  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy410);
+  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy410);
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
+}
+        break;
+      case 180: /* expr ::= nm DOT nm DOT nm */
+{
+  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-4].minor.yy410);
+  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy410);
+  Expr *temp3 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy410);
+  Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
+}
+        break;
+      case 183: /* expr ::= REGISTER */
+{yygotominor.yy172 = sqlite3RegisterExpr(pParse, &yymsp[0].minor.yy0);}
+        break;
+      case 184: /* expr ::= VARIABLE */
+{
+  Token *pToken = &yymsp[0].minor.yy0;
+  Expr *pExpr = yygotominor.yy172 = sqlite3PExpr(pParse, TK_VARIABLE, 0, 0, pToken);
+  sqlite3ExprAssignVarNumber(pParse, pExpr);
+}
+        break;
+      case 185: /* expr ::= expr COLLATE ids */
+{
+  yygotominor.yy172 = sqlite3ExprSetColl(pParse, yymsp[-2].minor.yy172, &yymsp[0].minor.yy410);
+}
+        break;
+      case 186: /* expr ::= CAST LP expr AS typetoken RP */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_CAST, yymsp[-3].minor.yy172, 0, &yymsp[-1].minor.yy410);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-5].minor.yy0,&yymsp[0].minor.yy0);
+}
+        break;
+      case 187: /* expr ::= ID LP distinct exprlist RP */
+{
+  if( yymsp[-1].minor.yy174 && yymsp[-1].minor.yy174->nExpr>SQLITE_MAX_FUNCTION_ARG ){
+    sqlite3ErrorMsg(pParse, "too many arguments on function %T", &yymsp[-4].minor.yy0);
+  }
+  yygotominor.yy172 = sqlite3ExprFunction(pParse, yymsp[-1].minor.yy174, &yymsp[-4].minor.yy0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-4].minor.yy0,&yymsp[0].minor.yy0);
+  if( yymsp[-2].minor.yy46 && yygotominor.yy172 ){
+    yygotominor.yy172->flags |= EP_Distinct;
+  }
+}
+        break;
+      case 188: /* expr ::= ID LP STAR RP */
+{
+  yygotominor.yy172 = sqlite3ExprFunction(pParse, 0, &yymsp[-3].minor.yy0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-3].minor.yy0,&yymsp[0].minor.yy0);
+}
+        break;
+      case 189: /* term ::= CTIME_KW */
+{
+  /* The CURRENT_TIME, CURRENT_DATE, and CURRENT_TIMESTAMP values are
+  ** treated as functions that return constants */
+  yygotominor.yy172 = sqlite3ExprFunction(pParse, 0,&yymsp[0].minor.yy0);
+  if( yygotominor.yy172 ){
+    yygotominor.yy172->op = TK_CONST_FUNC;  
+    yygotominor.yy172->span = yymsp[0].minor.yy0;
+  }
+}
+        break;
+      case 190: /* expr ::= expr AND expr */
+      case 191: /* expr ::= expr OR expr */
+      case 192: /* expr ::= expr LT|GT|GE|LE expr */
+      case 193: /* expr ::= expr EQ|NE expr */
+      case 194: /* expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
+      case 195: /* expr ::= expr PLUS|MINUS expr */
+      case 196: /* expr ::= expr STAR|SLASH|REM expr */
+      case 197: /* expr ::= expr CONCAT expr */
+{yygotominor.yy172 = sqlite3PExpr(pParse,yymsp[-1].major,yymsp[-2].minor.yy172,yymsp[0].minor.yy172,0);}
+        break;
+      case 198: /* likeop ::= LIKE_KW */
+      case 200: /* likeop ::= MATCH */
+{yygotominor.yy72.eOperator = yymsp[0].minor.yy0; yygotominor.yy72.not = 0;}
+        break;
+      case 199: /* likeop ::= NOT LIKE_KW */
+      case 201: /* likeop ::= NOT MATCH */
+{yygotominor.yy72.eOperator = yymsp[0].minor.yy0; yygotominor.yy72.not = 1;}
+        break;
+      case 204: /* expr ::= expr likeop expr escape */
+{
+  ExprList *pList;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[-1].minor.yy172, 0);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-3].minor.yy172, 0);
+  if( yymsp[0].minor.yy172 ){
+    pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy172, 0);
+  }
+  yygotominor.yy172 = sqlite3ExprFunction(pParse, pList, &yymsp[-2].minor.yy72.eOperator);
+  if( yymsp[-2].minor.yy72.not ) yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172, &yymsp[-3].minor.yy172->span, &yymsp[-1].minor.yy172->span);
+  if( yygotominor.yy172 ) yygotominor.yy172->flags |= EP_InfixFunc;
+}
+        break;
+      case 205: /* expr ::= expr ISNULL|NOTNULL */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, yymsp[0].major, yymsp[-1].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-1].minor.yy172->span,&yymsp[0].minor.yy0);
+}
+        break;
+      case 206: /* expr ::= expr IS NULL */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_ISNULL, yymsp[-2].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-2].minor.yy172->span,&yymsp[0].minor.yy0);
+}
+        break;
+      case 207: /* expr ::= expr NOT NULL */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOTNULL, yymsp[-2].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-2].minor.yy172->span,&yymsp[0].minor.yy0);
+}
+        break;
+      case 208: /* expr ::= expr IS NOT NULL */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOTNULL, yymsp[-3].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-3].minor.yy172->span,&yymsp[0].minor.yy0);
+}
+        break;
+      case 209: /* expr ::= NOT expr */
+      case 210: /* expr ::= BITNOT expr */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, yymsp[-1].major, yymsp[0].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy172->span);
+}
+        break;
+      case 211: /* expr ::= MINUS expr */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy172->span);
+}
+        break;
+      case 212: /* expr ::= PLUS expr */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_UPLUS, yymsp[0].minor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy172->span);
+}
+        break;
+      case 215: /* expr ::= expr between_op expr AND expr */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy172, 0);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy172, 0);
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_BETWEEN, yymsp[-4].minor.yy172, 0, 0);
+  if( yygotominor.yy172 ){
+    yygotominor.yy172->pList = pList;
+  }else{
+    sqlite3ExprListDelete(pList);
+  } 
+  if( yymsp[-3].minor.yy46 ) yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy172, 0, 0);
+  sqlite3ExprSpan(yygotominor.yy172,&yymsp[-4].minor.yy172->span,&yymsp[0].minor.yy172->span);
+}
+        break;
+      case 218: /* expr ::= expr in_op LP exprlist RP */
+{
+    yygotominor.yy172 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy172, 0, 0);
+    if( yygotominor.yy172 ){
+      yygotominor.yy172->pList = yymsp[-1].minor.yy174;
+      sqlite3ExprSetHeight(yygotominor.yy172);
+    }else{
+      sqlite3ExprListDelete(yymsp[-1].minor.yy174);
+    }
+    if( yymsp[-3].minor.yy46 ) yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy172, 0, 0);
+    sqlite3ExprSpan(yygotominor.yy172,&yymsp[-4].minor.yy172->span,&yymsp[0].minor.yy0);
+  }
+        break;
+      case 219: /* expr ::= LP select RP */
+{
+    yygotominor.yy172 = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0);
+    if( yygotominor.yy172 ){
+      yygotominor.yy172->pSelect = yymsp[-1].minor.yy219;
+      sqlite3ExprSetHeight(yygotominor.yy172);
+    }else{
+      sqlite3SelectDelete(yymsp[-1].minor.yy219);
+    }
+    sqlite3ExprSpan(yygotominor.yy172,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);
+  }
+        break;
+      case 220: /* expr ::= expr in_op LP select RP */
+{
+    yygotominor.yy172 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy172, 0, 0);
+    if( yygotominor.yy172 ){
+      yygotominor.yy172->pSelect = yymsp[-1].minor.yy219;
+      sqlite3ExprSetHeight(yygotominor.yy172);
+    }else{
+      sqlite3SelectDelete(yymsp[-1].minor.yy219);
+    }
+    if( yymsp[-3].minor.yy46 ) yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy172, 0, 0);
+    sqlite3ExprSpan(yygotominor.yy172,&yymsp[-4].minor.yy172->span,&yymsp[0].minor.yy0);
+  }
+        break;
+      case 221: /* expr ::= expr in_op nm dbnm */
+{
+    SrcList *pSrc = sqlite3SrcListAppend(pParse->db, 0,&yymsp[-1].minor.yy410,&yymsp[0].minor.yy410);
+    yygotominor.yy172 = sqlite3PExpr(pParse, TK_IN, yymsp[-3].minor.yy172, 0, 0);
+    if( yygotominor.yy172 ){
+      yygotominor.yy172->pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0,0);
+      sqlite3ExprSetHeight(yygotominor.yy172);
+    }else{
+      sqlite3SrcListDelete(pSrc);
+    }
+    if( yymsp[-2].minor.yy46 ) yygotominor.yy172 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy172, 0, 0);
+    sqlite3ExprSpan(yygotominor.yy172,&yymsp[-3].minor.yy172->span,yymsp[0].minor.yy410.z?&yymsp[0].minor.yy410:&yymsp[-1].minor.yy410);
+  }
+        break;
+      case 222: /* expr ::= EXISTS LP select RP */
+{
+    Expr *p = yygotominor.yy172 = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0);
+    if( p ){
+      p->pSelect = yymsp[-1].minor.yy219;
+      sqlite3ExprSpan(p,&yymsp[-3].minor.yy0,&yymsp[0].minor.yy0);
+      sqlite3ExprSetHeight(yygotominor.yy172);
+    }else{
+      sqlite3SelectDelete(yymsp[-1].minor.yy219);
+    }
+  }
+        break;
+      case 223: /* expr ::= CASE case_operand case_exprlist case_else END */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_CASE, yymsp[-3].minor.yy172, yymsp[-1].minor.yy172, 0);
+  if( yygotominor.yy172 ){
+    yygotominor.yy172->pList = yymsp[-2].minor.yy174;
+    sqlite3ExprSetHeight(yygotominor.yy172);
+  }else{
+    sqlite3ExprListDelete(yymsp[-2].minor.yy174);
+  }
+  sqlite3ExprSpan(yygotominor.yy172, &yymsp[-4].minor.yy0, &yymsp[0].minor.yy0);
+}
+        break;
+      case 224: /* case_exprlist ::= case_exprlist WHEN expr THEN expr */
+{
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy174, yymsp[-2].minor.yy172, 0);
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yygotominor.yy174, yymsp[0].minor.yy172, 0);
+}
+        break;
+      case 225: /* case_exprlist ::= WHEN expr THEN expr */
+{
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy172, 0);
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yygotominor.yy174, yymsp[0].minor.yy172, 0);
+}
+        break;
+      case 234: /* cmd ::= CREATE uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP */
+{
+  sqlite3CreateIndex(pParse, &yymsp[-6].minor.yy410, &yymsp[-5].minor.yy410, 
+                     sqlite3SrcListAppend(pParse->db,0,&yymsp[-3].minor.yy410,0), yymsp[-1].minor.yy174, yymsp[-9].minor.yy46,
+                      &yymsp[-10].minor.yy0, &yymsp[0].minor.yy0, SQLITE_SO_ASC, yymsp[-7].minor.yy46);
+}
+        break;
+      case 235: /* uniqueflag ::= UNIQUE */
+      case 283: /* raisetype ::= ABORT */
+{yygotominor.yy46 = OE_Abort;}
+        break;
+      case 236: /* uniqueflag ::= */
+{yygotominor.yy46 = OE_None;}
+        break;
+      case 239: /* idxlist ::= idxlist COMMA idxitem collate sortorder */
+{
+  Expr *p = 0;
+  if( yymsp[-1].minor.yy410.n>0 ){
+    p = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
+    sqlite3ExprSetColl(pParse, p, &yymsp[-1].minor.yy410);
+  }
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy174, p, &yymsp[-2].minor.yy410);
+  sqlite3ExprListCheckLength(pParse, yygotominor.yy174, "index");
+  if( yygotominor.yy174 ) yygotominor.yy174->a[yygotominor.yy174->nExpr-1].sortOrder = yymsp[0].minor.yy46;
+}
+        break;
+      case 240: /* idxlist ::= idxitem collate sortorder */
+{
+  Expr *p = 0;
+  if( yymsp[-1].minor.yy410.n>0 ){
+    p = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
+    sqlite3ExprSetColl(pParse, p, &yymsp[-1].minor.yy410);
+  }
+  yygotominor.yy174 = sqlite3ExprListAppend(pParse,0, p, &yymsp[-2].minor.yy410);
+  sqlite3ExprListCheckLength(pParse, yygotominor.yy174, "index");
+  if( yygotominor.yy174 ) yygotominor.yy174->a[yygotominor.yy174->nExpr-1].sortOrder = yymsp[0].minor.yy46;
+}
+        break;
+      case 242: /* collate ::= */
+{yygotominor.yy410.z = 0; yygotominor.yy410.n = 0;}
+        break;
+      case 244: /* cmd ::= DROP INDEX ifexists fullname */
+{sqlite3DropIndex(pParse, yymsp[0].minor.yy373, yymsp[-1].minor.yy46);}
+        break;
+      case 245: /* cmd ::= VACUUM */
+      case 246: /* cmd ::= VACUUM nm */
+{sqlite3Vacuum(pParse);}
+        break;
+      case 247: /* cmd ::= PRAGMA nm dbnm EQ nmnum */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy410,&yymsp[-2].minor.yy410,&yymsp[0].minor.yy410,0);}
+        break;
+      case 248: /* cmd ::= PRAGMA nm dbnm EQ ON */
+      case 249: /* cmd ::= PRAGMA nm dbnm EQ DELETE */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy410,&yymsp[-2].minor.yy410,&yymsp[0].minor.yy0,0);}
+        break;
+      case 250: /* cmd ::= PRAGMA nm dbnm EQ minus_num */
+{
+  sqlite3Pragma(pParse,&yymsp[-3].minor.yy410,&yymsp[-2].minor.yy410,&yymsp[0].minor.yy410,1);
+}
+        break;
+      case 251: /* cmd ::= PRAGMA nm dbnm LP nmnum RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy410,&yymsp[-3].minor.yy410,&yymsp[-1].minor.yy410,0);}
+        break;
+      case 252: /* cmd ::= PRAGMA nm dbnm */
+{sqlite3Pragma(pParse,&yymsp[-1].minor.yy410,&yymsp[0].minor.yy410,0,0);}
+        break;
+      case 260: /* cmd ::= CREATE trigger_decl BEGIN trigger_cmd_list END */
+{
+  Token all;
+  all.z = yymsp[-3].minor.yy410.z;
+  all.n = (yymsp[0].minor.yy0.z - yymsp[-3].minor.yy410.z) + yymsp[0].minor.yy0.n;
+  sqlite3FinishTrigger(pParse, yymsp[-1].minor.yy243, &all);
+}
+        break;
+      case 261: /* trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+{
+  sqlite3BeginTrigger(pParse, &yymsp[-7].minor.yy410, &yymsp[-6].minor.yy410, yymsp[-5].minor.yy46, yymsp[-4].minor.yy370.a, yymsp[-4].minor.yy370.b, yymsp[-2].minor.yy373, yymsp[0].minor.yy172, yymsp[-10].minor.yy46, yymsp[-8].minor.yy46);
+  yygotominor.yy410 = (yymsp[-6].minor.yy410.n==0?yymsp[-7].minor.yy410:yymsp[-6].minor.yy410);
+}
+        break;
+      case 262: /* trigger_time ::= BEFORE */
+      case 265: /* trigger_time ::= */
+{ yygotominor.yy46 = TK_BEFORE; }
+        break;
+      case 263: /* trigger_time ::= AFTER */
+{ yygotominor.yy46 = TK_AFTER;  }
+        break;
+      case 264: /* trigger_time ::= INSTEAD OF */
+{ yygotominor.yy46 = TK_INSTEAD;}
+        break;
+      case 266: /* trigger_event ::= DELETE|INSERT */
+      case 267: /* trigger_event ::= UPDATE */
+{yygotominor.yy370.a = yymsp[0].major; yygotominor.yy370.b = 0;}
+        break;
+      case 268: /* trigger_event ::= UPDATE OF inscollist */
+{yygotominor.yy370.a = TK_UPDATE; yygotominor.yy370.b = yymsp[0].minor.yy432;}
+        break;
+      case 271: /* when_clause ::= */
+      case 288: /* key_opt ::= */
+{ yygotominor.yy172 = 0; }
+        break;
+      case 272: /* when_clause ::= WHEN expr */
+      case 289: /* key_opt ::= KEY expr */
+{ yygotominor.yy172 = yymsp[0].minor.yy172; }
+        break;
+      case 273: /* trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+{
+  if( yymsp[-2].minor.yy243 ){
+    yymsp[-2].minor.yy243->pLast->pNext = yymsp[-1].minor.yy243;
+  }else{
+    yymsp[-2].minor.yy243 = yymsp[-1].minor.yy243;
+  }
+  yymsp[-2].minor.yy243->pLast = yymsp[-1].minor.yy243;
+  yygotominor.yy243 = yymsp[-2].minor.yy243;
+}
+        break;
+      case 274: /* trigger_cmd_list ::= */
+{ yygotominor.yy243 = 0; }
+        break;
+      case 275: /* trigger_cmd ::= UPDATE orconf nm SET setlist where_opt */
+{ yygotominor.yy243 = sqlite3TriggerUpdateStep(pParse->db, &yymsp[-3].minor.yy410, yymsp[-1].minor.yy174, yymsp[0].minor.yy172, yymsp[-4].minor.yy46); }
+        break;
+      case 276: /* trigger_cmd ::= insert_cmd INTO nm inscollist_opt VALUES LP itemlist RP */
+{yygotominor.yy243 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-5].minor.yy410, yymsp[-4].minor.yy432, yymsp[-1].minor.yy174, 0, yymsp[-7].minor.yy46);}
+        break;
+      case 277: /* trigger_cmd ::= insert_cmd INTO nm inscollist_opt select */
+{yygotominor.yy243 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-2].minor.yy410, yymsp[-1].minor.yy432, 0, yymsp[0].minor.yy219, yymsp[-4].minor.yy46);}
+        break;
+      case 278: /* trigger_cmd ::= DELETE FROM nm where_opt */
+{yygotominor.yy243 = sqlite3TriggerDeleteStep(pParse->db, &yymsp[-1].minor.yy410, yymsp[0].minor.yy172);}
+        break;
+      case 279: /* trigger_cmd ::= select */
+{yygotominor.yy243 = sqlite3TriggerSelectStep(pParse->db, yymsp[0].minor.yy219); }
+        break;
+      case 280: /* expr ::= RAISE LP IGNORE RP */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_RAISE, 0, 0, 0); 
+  if( yygotominor.yy172 ){
+    yygotominor.yy172->iColumn = OE_Ignore;
+    sqlite3ExprSpan(yygotominor.yy172, &yymsp[-3].minor.yy0, &yymsp[0].minor.yy0);
+  }
+}
+        break;
+      case 281: /* expr ::= RAISE LP raisetype COMMA nm RP */
+{
+  yygotominor.yy172 = sqlite3PExpr(pParse, TK_RAISE, 0, 0, &yymsp[-1].minor.yy410); 
+  if( yygotominor.yy172 ) {
+    yygotominor.yy172->iColumn = yymsp[-3].minor.yy46;
+    sqlite3ExprSpan(yygotominor.yy172, &yymsp[-5].minor.yy0, &yymsp[0].minor.yy0);
+  }
+}
+        break;
+      case 282: /* raisetype ::= ROLLBACK */
+{yygotominor.yy46 = OE_Rollback;}
+        break;
+      case 284: /* raisetype ::= FAIL */
+{yygotominor.yy46 = OE_Fail;}
+        break;
+      case 285: /* cmd ::= DROP TRIGGER ifexists fullname */
+{
+  sqlite3DropTrigger(pParse,yymsp[0].minor.yy373,yymsp[-1].minor.yy46);
+}
+        break;
+      case 286: /* cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+{
+  sqlite3Attach(pParse, yymsp[-3].minor.yy172, yymsp[-1].minor.yy172, yymsp[0].minor.yy172);
+}
+        break;
+      case 287: /* cmd ::= DETACH database_kw_opt expr */
+{
+  sqlite3Detach(pParse, yymsp[0].minor.yy172);
+}
+        break;
+      case 292: /* cmd ::= REINDEX */
+{sqlite3Reindex(pParse, 0, 0);}
+        break;
+      case 293: /* cmd ::= REINDEX nm dbnm */
+{sqlite3Reindex(pParse, &yymsp[-1].minor.yy410, &yymsp[0].minor.yy410);}
+        break;
+      case 294: /* cmd ::= ANALYZE */
+{sqlite3Analyze(pParse, 0, 0);}
+        break;
+      case 295: /* cmd ::= ANALYZE nm dbnm */
+{sqlite3Analyze(pParse, &yymsp[-1].minor.yy410, &yymsp[0].minor.yy410);}
+        break;
+      case 296: /* cmd ::= ALTER TABLE fullname RENAME TO nm */
+{
+  sqlite3AlterRenameTable(pParse,yymsp[-3].minor.yy373,&yymsp[0].minor.yy410);
+}
+        break;
+      case 297: /* cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column */
+{
+  sqlite3AlterFinishAddColumn(pParse, &yymsp[0].minor.yy410);
+}
+        break;
+      case 298: /* add_column_fullname ::= fullname */
+{
+  sqlite3AlterBeginAddColumn(pParse, yymsp[0].minor.yy373);
+}
+        break;
+      case 301: /* cmd ::= create_vtab */
+{sqlite3VtabFinishParse(pParse,0);}
+        break;
+      case 302: /* cmd ::= create_vtab LP vtabarglist RP */
+{sqlite3VtabFinishParse(pParse,&yymsp[0].minor.yy0);}
+        break;
+      case 303: /* create_vtab ::= CREATE VIRTUAL TABLE nm dbnm USING nm */
+{
+    sqlite3VtabBeginParse(pParse, &yymsp[-3].minor.yy410, &yymsp[-2].minor.yy410, &yymsp[0].minor.yy410);
+}
+        break;
+      case 306: /* vtabarg ::= */
+{sqlite3VtabArgInit(pParse);}
+        break;
+      case 308: /* vtabargtoken ::= ANY */
+      case 309: /* vtabargtoken ::= lp anylist RP */
+      case 310: /* lp ::= LP */
+      case 312: /* anylist ::= anylist ANY */
+{sqlite3VtabArgExtend(pParse,&yymsp[0].minor.yy0);}
+        break;
+  };
+  yygoto = yyRuleInfo[yyruleno].lhs;
+  yysize = yyRuleInfo[yyruleno].nrhs;
+  yypParser->yyidx -= yysize;
+  yyact = yy_find_reduce_action(yymsp[-yysize].stateno,yygoto);
+  if( yyact < YYNSTATE ){
+#ifdef NDEBUG
+    /* If we are not debugging and the reduce action popped at least
+    ** one element off the stack, then we can push the new element back
+    ** onto the stack here, and skip the stack overflow test in yy_shift().
+    ** That gives a significant speed improvement. */
+    if( yysize ){
+      yypParser->yyidx++;
+      yymsp -= yysize-1;
+      yymsp->stateno = yyact;
+      yymsp->major = yygoto;
+      yymsp->minor = yygotominor;
+    }else
+#endif
+    {
+      yy_shift(yypParser,yyact,yygoto,&yygotominor);
+    }
+  }else{
+    assert( yyact == YYNSTATE + YYNRULE + 1 );
+    yy_accept(yypParser);
+  }
+}
+
+/*
+** The following code executes when the parse fails
+*/
+static void yy_parse_failed(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
+  }
+#endif
+  while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser fails */
+  sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void yy_syntax_error(
+  yyParser *yypParser,           /* The parser */
+  int yymajor,                   /* The major type of the error token */
+  YYMINORTYPE yyminor            /* The minor type of the error token */
+){
+  sqlite3ParserARG_FETCH;
+#define TOKEN (yyminor.yy0)
+
+  assert( TOKEN.z[0] );  /* The tokenizer always gives us a token */
+  sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &TOKEN);
+  pParse->parseError = 1;
+  sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void yy_accept(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
+  }
+#endif
+  while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser accepts */
+  sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "sqlite3ParserAlloc" which describes the current state of the parser.
+** The second argument is the major token number.  The third is
+** the minor token.  The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3Parser(
+  void *yyp,                   /* The parser */
+  int yymajor,                 /* The major token code number */
+  sqlite3ParserTOKENTYPE yyminor       /* The value for the token */
+  sqlite3ParserARG_PDECL               /* Optional %extra_argument parameter */
+){
+  YYMINORTYPE yyminorunion;
+  int yyact;            /* The parser action. */
+  int yyendofinput;     /* True if we are at the end of input */
+#ifdef YYERRORSYMBOL
+  int yyerrorhit = 0;   /* True if yymajor has invoked an error */
+#endif
+  yyParser *yypParser;  /* The parser */
+
+  /* (re)initialize the parser, if necessary */
+  yypParser = (yyParser*)yyp;
+  if( yypParser->yyidx<0 ){
+#if YYSTACKDEPTH<=0
+    if( yypParser->yystksz <=0 ){
+      /*memset(&yyminorunion, 0, sizeof(yyminorunion));*/
+      yyminorunion = yyzerominor;
+      yyStackOverflow(yypParser, &yyminorunion);
+      return;
+    }
+#endif
+    yypParser->yyidx = 0;
+    yypParser->yyerrcnt = -1;
+    yypParser->yystack[0].stateno = 0;
+    yypParser->yystack[0].major = 0;
+  }
+  yyminorunion.yy0 = yyminor;
+  yyendofinput = (yymajor==0);
+  sqlite3ParserARG_STORE;
+
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sInput %s\n",yyTracePrompt,yyTokenName[yymajor]);
+  }
+#endif
+
+  do{
+    yyact = yy_find_shift_action(yypParser,yymajor);
+    if( yyact<YYNSTATE ){
+      assert( !yyendofinput );  /* Impossible to shift the $ token */
+      yy_shift(yypParser,yyact,yymajor,&yyminorunion);
+      yypParser->yyerrcnt--;
+      yymajor = YYNOCODE;
+    }else if( yyact < YYNSTATE + YYNRULE ){
+      yy_reduce(yypParser,yyact-YYNSTATE);
+    }else{
+      assert( yyact == YY_ERROR_ACTION );
+#ifdef YYERRORSYMBOL
+      int yymx;
+#endif
+#ifndef NDEBUG
+      if( yyTraceFILE ){
+        fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt);
+      }
+#endif
+#ifdef YYERRORSYMBOL
+      /* A syntax error has occurred.
+      ** The response to an error depends upon whether or not the
+      ** grammar defines an error token "ERROR".  
+      **
+      ** This is what we do if the grammar does define ERROR:
+      **
+      **  * Call the %syntax_error function.
+      **
+      **  * Begin popping the stack until we enter a state where
+      **    it is legal to shift the error symbol, then shift
+      **    the error symbol.
+      **
+      **  * Set the error count to three.
+      **
+      **  * Begin accepting and shifting new tokens.  No new error
+      **    processing will occur until three tokens have been
+      **    shifted successfully.
+      **
+      */
+      if( yypParser->yyerrcnt<0 ){
+        yy_syntax_error(yypParser,yymajor,yyminorunion);
+      }
+      yymx = yypParser->yystack[yypParser->yyidx].major;
+      if( yymx==YYERRORSYMBOL || yyerrorhit ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE,"%sDiscard input token %s\n",
+             yyTracePrompt,yyTokenName[yymajor]);
+        }
+#endif
+        yy_destructor(yymajor,&yyminorunion);
+        yymajor = YYNOCODE;
+      }else{
+         while(
+          yypParser->yyidx >= 0 &&
+          yymx != YYERRORSYMBOL &&
+          (yyact = yy_find_reduce_action(
+                        yypParser->yystack[yypParser->yyidx].stateno,
+                        YYERRORSYMBOL)) >= YYNSTATE
+        ){
+          yy_pop_parser_stack(yypParser);
+        }
+        if( yypParser->yyidx < 0 || yymajor==0 ){
+          yy_destructor(yymajor,&yyminorunion);
+          yy_parse_failed(yypParser);
+          yymajor = YYNOCODE;
+        }else if( yymx!=YYERRORSYMBOL ){
+          YYMINORTYPE u2;
+          u2.YYERRSYMDT = 0;
+          yy_shift(yypParser,yyact,YYERRORSYMBOL,&u2);
+        }
+      }
+      yypParser->yyerrcnt = 3;
+      yyerrorhit = 1;
+#else  /* YYERRORSYMBOL is not defined */
+      /* This is what we do if the grammar does not define ERROR:
+      **
+      **  * Report an error message, and throw away the input token.
+      **
+      **  * If the input token is $, then fail the parse.
+      **
+      ** As before, subsequent error messages are suppressed until
+      ** three input tokens have been successfully shifted.
+      */
+      if( yypParser->yyerrcnt<=0 ){
+        yy_syntax_error(yypParser,yymajor,yyminorunion);
+      }
+      yypParser->yyerrcnt = 3;
+      yy_destructor(yymajor,&yyminorunion);
+      if( yyendofinput ){
+        yy_parse_failed(yypParser);
+      }
+      yymajor = YYNOCODE;
+#endif
+    }
+  }while( yymajor!=YYNOCODE && yypParser->yyidx>=0 );
+  return;
+}
+
+/************** End of parse.c ***********************************************/
+/************** Begin file tokenize.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that splits an SQL input string up into
+** individual tokens and sends those tokens one-by-one over to the
+** parser for analysis.
+**
+** $Id: tokenize.c,v 1.142 2008/04/28 18:46:43 drh Exp $
+*/
+
+/*
+** The charMap() macro maps alphabetic characters into their
+** lower-case ASCII equivalent.  On ASCII machines, this is just
+** an upper-to-lower case map.  On EBCDIC machines we also need
+** to adjust the encoding.  Only alphabetic characters and underscores
+** need to be translated.
+*/
+#ifdef SQLITE_ASCII
+# define charMap(X) sqlite3UpperToLower[(unsigned char)X]
+#endif
+#ifdef SQLITE_EBCDIC
+# define charMap(X) ebcdicToAscii[(unsigned char)X]
+const unsigned char ebcdicToAscii[] = {
+/* 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 0x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 1x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 2x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 3x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 4x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 5x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 95,  0,  0,  /* 6x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 7x */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* 8x */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* 9x */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ax */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Bx */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* Cx */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* Dx */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ex */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Fx */
+};
+#endif
+
+/*
+** The sqlite3KeywordCode function looks up an identifier to determine if
+** it is a keyword.  If it is a keyword, the token code of that keyword is 
+** returned.  If the input is not a keyword, TK_ID is returned.
+**
+** The implementation of this routine was generated by a program,
+** mkkeywordhash.h, located in the tool subdirectory of the distribution.
+** The output of the mkkeywordhash.c program is written into a file
+** named keywordhash.h and then included into this source file by
+** the #include below.
+*/
+/************** Include keywordhash.h in the middle of tokenize.c ************/
+/************** Begin file keywordhash.h *************************************/
+/***** This file contains automatically generated code ******
+**
+** The code in this file has been automatically generated by
+**
+**     $Header: /sqlite/sqlite/tool/mkkeywordhash.c,v 1.31 2007/07/30 18:26:20 rse Exp $
+**
+** The code in this file implements a function that determines whether
+** or not a given identifier is really an SQL keyword.  The same thing
+** might be implemented more directly using a hand-written hash table.
+** But by using this automatically generated code, the size of the code
+** is substantially reduced.  This is important for embedded applications
+** on platforms with limited memory.
+*/
+/* Hash score: 165 */
+static int keywordCode(const char *z, int n){
+  /* zText[] encodes 775 bytes of keywords in 526 bytes */
+  static const char zText[526] =
+    "BEFOREIGNOREGEXPLAINSTEADDESCAPEACHECKEYCONSTRAINTERSECTABLEFT"
+    "HENDATABASELECTRANSACTIONATURALTERAISELSEXCEPTRIGGEREFERENCES"
+    "UNIQUERYATTACHAVINGROUPDATEMPORARYBEGINNEREINDEXCLUSIVEXISTSBETWEEN"
+    "OTNULLIKECASCADEFERRABLECASECOLLATECREATECURRENT_DATEDELETEDETACH"
+    "IMMEDIATEJOINSERTMATCHPLANALYZEPRAGMABORTVALUESVIRTUALIMITWHEN"
+    "WHERENAMEAFTEREPLACEANDEFAULTAUTOINCREMENTCASTCOLUMNCOMMITCONFLICT"
+    "CROSSCURRENT_TIMESTAMPRIMARYDEFERREDISTINCTDROPFAILFROMFULLGLOB"
+    "YIFINTOFFSETISNULLORDERESTRICTOUTERIGHTROLLBACKROWUNIONUSINGVACUUM"
+    "VIEWINITIALLY";
+  static const unsigned char aHash[127] = {
+      63,  92, 109,  61,   0,  38,   0,   0,  69,   0,  64,   0,   0,
+     102,   4,  65,   7,   0, 108,  72, 103,  99,   0,  22,   0,   0,
+     113,   0, 111, 106,   0,  18,  80,   0,   1,   0,   0,  56,  57,
+       0,  55,  11,   0,  33,  77,  89,   0, 110,  88,   0,   0,  45,
+       0,  90,  54,   0,  20,   0, 114,  34,  19,   0,  10,  97,  28,
+      83,   0,   0, 116,  93,  47, 115,  41,  12,  44,   0,  78,   0,
+      87,  29,   0,  86,   0,   0,   0,  82,  79,  84,  75,  96,   6,
+      14,  95,   0,  68,   0,  21,  76,  98,  27,   0, 112,  67, 104,
+      49,  40,  71,   0,   0,  81, 100,   0, 107,   0,  15,   0,   0,
+      24,   0,  73,  42,  50,   0,  16,  48,   0,  37,
+  };
+  static const unsigned char aNext[116] = {
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   9,   0,   0,   0,
+       0,   0,   0,   0,   5,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  32,   0,   0,
+      17,   0,   0,   0,  36,  39,   0,   0,  25,   0,   0,  31,   0,
+       0,   0,  43,  52,   0,   0,   0,  53,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,  51,   0,   0,   0,   0,  26,   0,   8,  46,
+       2,   0,   0,   0,   0,   0,   0,   0,   3,  58,  66,   0,  13,
+       0,  91,  85,   0,  94,   0,  74,   0,   0,  62,   0,  35, 101,
+       0,   0, 105,  23,  30,  60,  70,   0,   0,  59,   0,   0,
+  };
+  static const unsigned char aLen[116] = {
+       6,   7,   3,   6,   6,   7,   7,   3,   4,   6,   4,   5,   3,
+      10,   9,   5,   4,   4,   3,   8,   2,   6,  11,   2,   7,   5,
+       5,   4,   6,   7,  10,   6,   5,   6,   6,   5,   6,   4,   9,
+       2,   5,   5,   7,   5,   9,   6,   7,   7,   3,   4,   4,   7,
+       3,  10,   4,   7,   6,  12,   6,   6,   9,   4,   6,   5,   4,
+       7,   6,   5,   6,   7,   5,   4,   5,   6,   5,   7,   3,   7,
+      13,   2,   2,   4,   6,   6,   8,   5,  17,  12,   7,   8,   8,
+       2,   4,   4,   4,   4,   4,   2,   2,   4,   6,   2,   3,   6,
+       5,   8,   5,   5,   8,   3,   5,   5,   6,   4,   9,   3,
+  };
+  static const unsigned short int aOffset[116] = {
+       0,   2,   2,   6,  10,  13,  18,  23,  25,  26,  31,  33,  37,
+      40,  47,  55,  58,  61,  63,  65,  70,  71,  76,  85,  86,  91,
+      95,  99, 102, 107, 113, 123, 126, 131, 136, 141, 144, 148, 148,
+     152, 157, 160, 164, 166, 169, 177, 183, 189, 189, 192, 195, 199,
+     200, 204, 214, 218, 225, 231, 243, 249, 255, 264, 266, 272, 277,
+     279, 286, 291, 296, 302, 308, 313, 317, 320, 326, 330, 337, 339,
+     346, 348, 350, 359, 363, 369, 375, 383, 388, 388, 404, 411, 418,
+     419, 426, 430, 434, 438, 442, 445, 447, 449, 452, 452, 455, 458,
+     464, 468, 476, 480, 485, 493, 496, 501, 506, 512, 516, 521,
+  };
+  static const unsigned char aCode[116] = {
+    TK_BEFORE,     TK_FOREIGN,    TK_FOR,        TK_IGNORE,     TK_LIKE_KW,    
+    TK_EXPLAIN,    TK_INSTEAD,    TK_ADD,        TK_DESC,       TK_ESCAPE,     
+    TK_EACH,       TK_CHECK,      TK_KEY,        TK_CONSTRAINT, TK_INTERSECT,  
+    TK_TABLE,      TK_JOIN_KW,    TK_THEN,       TK_END,        TK_DATABASE,   
+    TK_AS,         TK_SELECT,     TK_TRANSACTION,TK_ON,         TK_JOIN_KW,    
+    TK_ALTER,      TK_RAISE,      TK_ELSE,       TK_EXCEPT,     TK_TRIGGER,    
+    TK_REFERENCES, TK_UNIQUE,     TK_QUERY,      TK_ATTACH,     TK_HAVING,     
+    TK_GROUP,      TK_UPDATE,     TK_TEMP,       TK_TEMP,       TK_OR,         
+    TK_BEGIN,      TK_JOIN_KW,    TK_REINDEX,    TK_INDEX,      TK_EXCLUSIVE,  
+    TK_EXISTS,     TK_BETWEEN,    TK_NOTNULL,    TK_NOT,        TK_NULL,       
+    TK_LIKE_KW,    TK_CASCADE,    TK_ASC,        TK_DEFERRABLE, TK_CASE,       
+    TK_COLLATE,    TK_CREATE,     TK_CTIME_KW,   TK_DELETE,     TK_DETACH,     
+    TK_IMMEDIATE,  TK_JOIN,       TK_INSERT,     TK_MATCH,      TK_PLAN,       
+    TK_ANALYZE,    TK_PRAGMA,     TK_ABORT,      TK_VALUES,     TK_VIRTUAL,    
+    TK_LIMIT,      TK_WHEN,       TK_WHERE,      TK_RENAME,     TK_AFTER,      
+    TK_REPLACE,    TK_AND,        TK_DEFAULT,    TK_AUTOINCR,   TK_TO,         
+    TK_IN,         TK_CAST,       TK_COLUMNKW,   TK_COMMIT,     TK_CONFLICT,   
+    TK_JOIN_KW,    TK_CTIME_KW,   TK_CTIME_KW,   TK_PRIMARY,    TK_DEFERRED,   
+    TK_DISTINCT,   TK_IS,         TK_DROP,       TK_FAIL,       TK_FROM,       
+    TK_JOIN_KW,    TK_LIKE_KW,    TK_BY,         TK_IF,         TK_INTO,       
+    TK_OFFSET,     TK_OF,         TK_SET,        TK_ISNULL,     TK_ORDER,      
+    TK_RESTRICT,   TK_JOIN_KW,    TK_JOIN_KW,    TK_ROLLBACK,   TK_ROW,        
+    TK_UNION,      TK_USING,      TK_VACUUM,     TK_VIEW,       TK_INITIALLY,  
+    TK_ALL,        
+  };
+  int h, i;
+  if( n<2 ) return TK_ID;
+  h = ((charMap(z[0])*4) ^
+      (charMap(z[n-1])*3) ^
+      n) % 127;
+  for(i=((int)aHash[h])-1; i>=0; i=((int)aNext[i])-1){
+    if( aLen[i]==n && sqlite3StrNICmp(&zText[aOffset[i]],z,n)==0 ){
+      return aCode[i];
+    }
+  }
+  return TK_ID;
+}
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char *z, int n){
+  return keywordCode((char*)z, n);
+}
+
+/************** End of keywordhash.h *****************************************/
+/************** Continuing where we left off in tokenize.c *******************/
+
+
+/*
+** If X is a character that can be used in an identifier then
+** IdChar(X) will be true.  Otherwise it is false.
+**
+** For ASCII, any character with the high-order bit set is
+** allowed in an identifier.  For 7-bit characters, 
+** sqlite3IsIdChar[X] must be 1.
+**
+** For EBCDIC, the rules are more complex but have the same
+** end result.
+**
+** Ticket #1066.  the SQL standard does not allow '$' in the
+** middle of identfiers.  But many SQL implementations do. 
+** SQLite will allow '$' in identifiers for compatibility.
+** But the feature is undocumented.
+*/
+#ifdef SQLITE_ASCII
+SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+};
+#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 4x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0,  /* 5x */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0,  /* 6x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,  /* 7x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0,  /* 8x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0,  /* 9x */
+    1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0,  /* Ax */
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* Bx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Cx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Dx */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Ex */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0,  /* Fx */
+};
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+
+
+/*
+** Return the length of the token that begins at z[0]. 
+** Store the token type in *tokenType before returning.
+*/
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
+  int i, c;
+  switch( *z ){
+    case ' ': case '\t': case '\n': case '\f': case '\r': {
+      for(i=1; isspace(z[i]); i++){}
+      *tokenType = TK_SPACE;
+      return i;
+    }
+    case '-': {
+      if( z[1]=='-' ){
+        for(i=2; (c=z[i])!=0 && c!='\n'; i++){}
+        *tokenType = TK_COMMENT;
+        return i;
+      }
+      *tokenType = TK_MINUS;
+      return 1;
+    }
+    case '(': {
+      *tokenType = TK_LP;
+      return 1;
+    }
+    case ')': {
+      *tokenType = TK_RP;
+      return 1;
+    }
+    case ';': {
+      *tokenType = TK_SEMI;
+      return 1;
+    }
+    case '+': {
+      *tokenType = TK_PLUS;
+      return 1;
+    }
+    case '*': {
+      *tokenType = TK_STAR;
+      return 1;
+    }
+    case '/': {
+      if( z[1]!='*' || z[2]==0 ){
+        *tokenType = TK_SLASH;
+        return 1;
+      }
+      for(i=3, c=z[2]; (c!='*' || z[i]!='/') && (c=z[i])!=0; i++){}
+      if( c ) i++;
+      *tokenType = TK_COMMENT;
+      return i;
+    }
+    case '%': {
+      *tokenType = TK_REM;
+      return 1;
+    }
+    case '=': {
+      *tokenType = TK_EQ;
+      return 1 + (z[1]=='=');
+    }
+    case '<': {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_LE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_NE;
+        return 2;
+      }else if( c=='<' ){
+        *tokenType = TK_LSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_LT;
+        return 1;
+      }
+    }
+    case '>': {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_GE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_RSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_GT;
+        return 1;
+      }
+    }
+    case '!': {
+      if( z[1]!='=' ){
+        *tokenType = TK_ILLEGAL;
+        return 2;
+      }else{
+        *tokenType = TK_NE;
+        return 2;
+      }
+    }
+    case '|': {
+      if( z[1]!='|' ){
+        *tokenType = TK_BITOR;
+        return 1;
+      }else{
+        *tokenType = TK_CONCAT;
+        return 2;
+      }
+    }
+    case ',': {
+      *tokenType = TK_COMMA;
+      return 1;
+    }
+    case '&': {
+      *tokenType = TK_BITAND;
+      return 1;
+    }
+    case '~': {
+      *tokenType = TK_BITNOT;
+      return 1;
+    }
+    case '`':
+    case '\'':
+    case '"': {
+      int delim = z[0];
+      for(i=1; (c=z[i])!=0; i++){
+        if( c==delim ){
+          if( z[i+1]==delim ){
+            i++;
+          }else{
+            break;
+          }
+        }
+      }
+      if( c ){
+        *tokenType = TK_STRING;
+        return i+1;
+      }else{
+        *tokenType = TK_ILLEGAL;
+        return i;
+      }
+    }
+    case '.': {
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      if( !isdigit(z[1]) )
+#endif
+      {
+        *tokenType = TK_DOT;
+        return 1;
+      }
+      /* If the next character is a digit, this is a floating point
+      ** number that begins with ".".  Fall thru into the next case */
+    }
+    case '0': case '1': case '2': case '3': case '4':
+    case '5': case '6': case '7': case '8': case '9': {
+      *tokenType = TK_INTEGER;
+      for(i=0; isdigit(z[i]); i++){}
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      if( z[i]=='.' ){
+        i++;
+        while( isdigit(z[i]) ){ i++; }
+        *tokenType = TK_FLOAT;
+      }
+      if( (z[i]=='e' || z[i]=='E') &&
+           ( isdigit(z[i+1]) 
+            || ((z[i+1]=='+' || z[i+1]=='-') && isdigit(z[i+2]))
+           )
+      ){
+        i += 2;
+        while( isdigit(z[i]) ){ i++; }
+        *tokenType = TK_FLOAT;
+      }
+#endif
+      while( IdChar(z[i]) ){
+        *tokenType = TK_ILLEGAL;
+        i++;
+      }
+      return i;
+    }
+    case '[': {
+      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
+      *tokenType = c==']' ? TK_ID : TK_ILLEGAL;
+      return i;
+    }
+    case '?': {
+      *tokenType = TK_VARIABLE;
+      for(i=1; isdigit(z[i]); i++){}
+      return i;
+    }
+    case '#': {
+      for(i=1; isdigit(z[i]); i++){}
+      if( i>1 ){
+        /* Parameters of the form #NNN (where NNN is a number) are used
+        ** internally by sqlite3NestedParse.  */
+        *tokenType = TK_REGISTER;
+        return i;
+      }
+      /* Fall through into the next case if the '#' is not followed by
+      ** a digit. Try to match #AAAA where AAAA is a parameter name. */
+    }
+#ifndef SQLITE_OMIT_TCL_VARIABLE
+    case '$':
+#endif
+    case '@':  /* For compatibility with MS SQL Server */
+    case ':': {
+      int n = 0;
+      *tokenType = TK_VARIABLE;
+      for(i=1; (c=z[i])!=0; i++){
+        if( IdChar(c) ){
+          n++;
+#ifndef SQLITE_OMIT_TCL_VARIABLE
+        }else if( c=='(' && n>0 ){
+          do{
+            i++;
+          }while( (c=z[i])!=0 && !isspace(c) && c!=')' );
+          if( c==')' ){
+            i++;
+          }else{
+            *tokenType = TK_ILLEGAL;
+          }
+          break;
+        }else if( c==':' && z[i+1]==':' ){
+          i++;
+#endif
+        }else{
+          break;
+        }
+      }
+      if( n==0 ) *tokenType = TK_ILLEGAL;
+      return i;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case 'x': case 'X': {
+      if( z[1]=='\'' ){
+        *tokenType = TK_BLOB;
+        for(i=2; (c=z[i])!=0 && c!='\''; i++){
+          if( !isxdigit(c) ){
+            *tokenType = TK_ILLEGAL;
+          }
+        }
+        if( i%2 || !c ) *tokenType = TK_ILLEGAL;
+        if( c ) i++;
+        return i;
+      }
+      /* Otherwise fall through to the next case */
+    }
+#endif
+    default: {
+      if( !IdChar(*z) ){
+        break;
+      }
+      for(i=1; IdChar(z[i]); i++){}
+      *tokenType = keywordCode((char*)z, i);
+      return i;
+    }
+  }
+  *tokenType = TK_ILLEGAL;
+  return 1;
+}
+
+/*
+** Run the parser on the given SQL string.  The parser structure is
+** passed in.  An SQLITE_ status code is returned.  If an error occurs
+** and pzErrMsg!=NULL then an error message might be written into 
+** memory obtained from sqlite3_malloc() and *pzErrMsg made to point to that
+** error message.  Or maybe not.
+*/
+SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
+  int nErr = 0;
+  int i;
+  void *pEngine;
+  int tokenType;
+  int lastTokenParsed = -1;
+  sqlite3 *db = pParse->db;
+  int mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+
+  if( db->activeVdbeCnt==0 ){
+    db->u1.isInterrupted = 0;
+  }
+  pParse->rc = SQLITE_OK;
+  pParse->zTail = pParse->zSql = zSql;
+  i = 0;
+  pEngine = sqlite3ParserAlloc((void*(*)(size_t))sqlite3_malloc);
+  if( pEngine==0 ){
+    db->mallocFailed = 1;
+    return SQLITE_NOMEM;
+  }
+  assert( pParse->sLastToken.dyn==0 );
+  assert( pParse->pNewTable==0 );
+  assert( pParse->pNewTrigger==0 );
+  assert( pParse->nVar==0 );
+  assert( pParse->nVarExpr==0 );
+  assert( pParse->nVarExprAlloc==0 );
+  assert( pParse->apVarExpr==0 );
+  while( !db->mallocFailed && zSql[i]!=0 ){
+    assert( i>=0 );
+    pParse->sLastToken.z = (u8*)&zSql[i];
+    assert( pParse->sLastToken.dyn==0 );
+    pParse->sLastToken.n = sqlite3GetToken((unsigned char*)&zSql[i],&tokenType);
+    i += pParse->sLastToken.n;
+    if( i>mxSqlLen ){
+      pParse->rc = SQLITE_TOOBIG;
+      break;
+    }
+    switch( tokenType ){
+      case TK_SPACE:
+      case TK_COMMENT: {
+        if( db->u1.isInterrupted ){
+          pParse->rc = SQLITE_INTERRUPT;
+          sqlite3SetString(pzErrMsg, "interrupt", (char*)0);
+          goto abort_parse;
+        }
+        break;
+      }
+      case TK_ILLEGAL: {
+        if( pzErrMsg ){
+          sqlite3_free(*pzErrMsg);
+          *pzErrMsg = sqlite3MPrintf(db, "unrecognized token: \"%T\"",
+                          &pParse->sLastToken);
+        }
+        nErr++;
+        goto abort_parse;
+      }
+      case TK_SEMI: {
+        pParse->zTail = &zSql[i];
+        /* Fall thru into the default case */
+      }
+      default: {
+        sqlite3Parser(pEngine, tokenType, pParse->sLastToken, pParse);
+        lastTokenParsed = tokenType;
+        if( pParse->rc!=SQLITE_OK ){
+          goto abort_parse;
+        }
+        break;
+      }
+    }
+  }
+abort_parse:
+  if( zSql[i]==0 && nErr==0 && pParse->rc==SQLITE_OK ){
+    if( lastTokenParsed!=TK_SEMI ){
+      sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
+      pParse->zTail = &zSql[i];
+    }
+    sqlite3Parser(pEngine, 0, pParse->sLastToken, pParse);
+  }
+  sqlite3ParserFree(pEngine, sqlite3_free);
+  if( db->mallocFailed ){
+    pParse->rc = SQLITE_NOMEM;
+  }
+  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
+    sqlite3SetString(&pParse->zErrMsg, sqlite3ErrStr(pParse->rc), (char*)0);
+  }
+  if( pParse->zErrMsg ){
+    if( pzErrMsg && *pzErrMsg==0 ){
+      *pzErrMsg = pParse->zErrMsg;
+    }else{
+      sqlite3_free(pParse->zErrMsg);
+    }
+    pParse->zErrMsg = 0;
+    nErr++;
+  }
+  if( pParse->pVdbe && pParse->nErr>0 && pParse->nested==0 ){
+    sqlite3VdbeDelete(pParse->pVdbe);
+    pParse->pVdbe = 0;
+  }
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  if( pParse->nested==0 ){
+    sqlite3_free(pParse->aTableLock);
+    pParse->aTableLock = 0;
+    pParse->nTableLock = 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_free(pParse->apVtabLock);
+#endif
+
+  if( !IN_DECLARE_VTAB ){
+    /* If the pParse->declareVtab flag is set, do not delete any table 
+    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
+    ** will take responsibility for freeing the Table structure.
+    */
+    sqlite3DeleteTable(pParse->pNewTable);
+  }
+
+  sqlite3DeleteTrigger(pParse->pNewTrigger);
+  sqlite3_free(pParse->apVarExpr);
+  if( nErr>0 && (pParse->rc==SQLITE_OK || pParse->rc==SQLITE_DONE) ){
+    pParse->rc = SQLITE_ERROR;
+  }
+  return nErr;
+}
+
+/************** End of tokenize.c ********************************************/
+/************** Begin file complete.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that implements the sqlite3_complete() API.
+** This code used to be part of the tokenizer.c source file.  But by
+** separating it out, the code will be automatically omitted from
+** static links that do not use it.
+**
+** $Id: complete.c,v 1.6 2007/08/27 23:26:59 drh Exp $
+*/
+#ifndef SQLITE_OMIT_COMPLETE
+
+/*
+** This is defined in tokenize.c.  We just have to import the definition.
+*/
+#ifndef SQLITE_AMALGAMATION
+#ifdef SQLITE_ASCII
+SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[];
+#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+#endif /* SQLITE_AMALGAMATION */
+
+
+/*
+** Token types used by the sqlite3_complete() routine.  See the header
+** comments on that procedure for additional information.
+*/
+#define tkSEMI    0
+#define tkWS      1
+#define tkOTHER   2
+#define tkEXPLAIN 3
+#define tkCREATE  4
+#define tkTEMP    5
+#define tkTRIGGER 6
+#define tkEND     7
+
+/*
+** Return TRUE if the given SQL string ends in a semicolon.
+**
+** Special handling is require for CREATE TRIGGER statements.
+** Whenever the CREATE TRIGGER keywords are seen, the statement
+** must end with ";END;".
+**
+** This implementation uses a state machine with 7 states:
+**
+**   (0) START     At the beginning or end of an SQL statement.  This routine
+**                 returns 1 if it ends in the START state and 0 if it ends
+**                 in any other state.
+**
+**   (1) NORMAL    We are in the middle of statement which ends with a single
+**                 semicolon.
+**
+**   (2) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
+**                 a statement.
+**
+**   (3) CREATE    The keyword CREATE has been seen at the beginning of a
+**                 statement, possibly preceeded by EXPLAIN and/or followed by
+**                 TEMP or TEMPORARY
+**
+**   (4) TRIGGER   We are in the middle of a trigger definition that must be
+**                 ended by a semicolon, the keyword END, and another semicolon.
+**
+**   (5) SEMI      We've seen the first semicolon in the ";END;" that occurs at
+**                 the end of a trigger definition.
+**
+**   (6) END       We've seen the ";END" of the ";END;" that occurs at the end
+**                 of a trigger difinition.
+**
+** Transitions between states above are determined by tokens extracted
+** from the input.  The following tokens are significant:
+**
+**   (0) tkSEMI      A semicolon.
+**   (1) tkWS        Whitespace
+**   (2) tkOTHER     Any other SQL token.
+**   (3) tkEXPLAIN   The "explain" keyword.
+**   (4) tkCREATE    The "create" keyword.
+**   (5) tkTEMP      The "temp" or "temporary" keyword.
+**   (6) tkTRIGGER   The "trigger" keyword.
+**   (7) tkEND       The "end" keyword.
+**
+** Whitespace never causes a state transition and is always ignored.
+**
+** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
+** to recognize the end of a trigger can be omitted.  All we have to do
+** is look for a semicolon that is not part of an string or comment.
+*/
+SQLITE_API int sqlite3_complete(const char *zSql){
+  u8 state = 0;   /* Current state, using numbers defined in header comment */
+  u8 token;       /* Value of the next token */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* A complex statement machine used to detect the end of a CREATE TRIGGER
+  ** statement.  This is the normal case.
+  */
+  static const u8 trans[7][8] = {
+                     /* Token:                                                */
+     /* State:       **  SEMI  WS  OTHER EXPLAIN  CREATE  TEMP  TRIGGER  END  */
+     /* 0   START: */ {    0,  0,     1,      2,      3,    1,       1,   1,  },
+     /* 1  NORMAL: */ {    0,  1,     1,      1,      1,    1,       1,   1,  },
+     /* 2 EXPLAIN: */ {    0,  2,     1,      1,      3,    1,       1,   1,  },
+     /* 3  CREATE: */ {    0,  3,     1,      1,      1,    3,       4,   1,  },
+     /* 4 TRIGGER: */ {    5,  4,     4,      4,      4,    4,       4,   4,  },
+     /* 5    SEMI: */ {    5,  5,     4,      4,      4,    4,       4,   6,  },
+     /* 6     END: */ {    0,  6,     4,      4,      4,    4,       4,   4,  },
+  };
+#else
+  /* If triggers are not suppored by this compile then the statement machine
+  ** used to detect the end of a statement is much simplier
+  */
+  static const u8 trans[2][3] = {
+                     /* Token:           */
+     /* State:       **  SEMI  WS  OTHER */
+     /* 0   START: */ {    0,  0,     1, },
+     /* 1  NORMAL: */ {    0,  1,     1, },
+  };
+#endif /* SQLITE_OMIT_TRIGGER */
+
+  while( *zSql ){
+    switch( *zSql ){
+      case ';': {  /* A semicolon */
+        token = tkSEMI;
+        break;
+      }
+      case ' ':
+      case '\r':
+      case '\t':
+      case '\n':
+      case '\f': {  /* White space is ignored */
+        token = tkWS;
+        break;
+      }
+      case '/': {   /* C-style comments */
+        if( zSql[1]!='*' ){
+          token = tkOTHER;
+          break;
+        }
+        zSql += 2;
+        while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }
+        if( zSql[0]==0 ) return 0;
+        zSql++;
+        token = tkWS;
+        break;
+      }
+      case '-': {   /* SQL-style comments from "--" to end of line */
+        if( zSql[1]!='-' ){
+          token = tkOTHER;
+          break;
+        }
+        while( *zSql && *zSql!='\n' ){ zSql++; }
+        if( *zSql==0 ) return state==0;
+        token = tkWS;
+        break;
+      }
+      case '[': {   /* Microsoft-style identifiers in [...] */
+        zSql++;
+        while( *zSql && *zSql!=']' ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      case '`':     /* Grave-accent quoted symbols used by MySQL */
+      case '"':     /* single- and double-quoted strings */
+      case '\'': {
+        int c = *zSql;
+        zSql++;
+        while( *zSql && *zSql!=c ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      default: {
+        int c;
+        if( IdChar((u8)*zSql) ){
+          /* Keywords and unquoted identifiers */
+          int nId;
+          for(nId=1; IdChar(zSql[nId]); nId++){}
+#ifdef SQLITE_OMIT_TRIGGER
+          token = tkOTHER;
+#else
+          switch( *zSql ){
+            case 'c': case 'C': {
+              if( nId==6 && sqlite3StrNICmp(zSql, "create", 6)==0 ){
+                token = tkCREATE;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 't': case 'T': {
+              if( nId==7 && sqlite3StrNICmp(zSql, "trigger", 7)==0 ){
+                token = tkTRIGGER;
+              }else if( nId==4 && sqlite3StrNICmp(zSql, "temp", 4)==0 ){
+                token = tkTEMP;
+              }else if( nId==9 && sqlite3StrNICmp(zSql, "temporary", 9)==0 ){
+                token = tkTEMP;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 'e':  case 'E': {
+              if( nId==3 && sqlite3StrNICmp(zSql, "end", 3)==0 ){
+                token = tkEND;
+              }else
+#ifndef SQLITE_OMIT_EXPLAIN
+              if( nId==7 && sqlite3StrNICmp(zSql, "explain", 7)==0 ){
+                token = tkEXPLAIN;
+              }else
+#endif
+              {
+                token = tkOTHER;
+              }
+              break;
+            }
+            default: {
+              token = tkOTHER;
+              break;
+            }
+          }
+#endif /* SQLITE_OMIT_TRIGGER */
+          zSql += nId-1;
+        }else{
+          /* Operators and special symbols */
+          token = tkOTHER;
+        }
+        break;
+      }
+    }
+    state = trans[state][token];
+    zSql++;
+  }
+  return state==0;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine is the same as the sqlite3_complete() routine described
+** above, except that the parameter is required to be UTF-16 encoded, not
+** UTF-8.
+*/
+SQLITE_API int sqlite3_complete16(const void *zSql){
+  sqlite3_value *pVal;
+  char const *zSql8;
+  int rc = SQLITE_NOMEM;
+
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zSql8 ){
+    rc = sqlite3_complete(zSql8);
+  }
+  sqlite3ValueFree(pVal);
+  return sqlite3ApiExit(0, rc);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_COMPLETE */
+
+/************** End of complete.c ********************************************/
+/************** Begin file main.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+**
+** $Id: main.c,v 1.439 2008/05/13 13:27:34 drh Exp $
+*/
+#ifdef SQLITE_ENABLE_FTS3
+/************** Include fts3.h in the middle of main.c ***********************/
+/************** Begin file fts3.h ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** FTS3 library.  All it does is declare the sqlite3Fts3Init() interface.
+*/
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of fts3.h ************************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+
+/*
+** The version of the library
+*/
+SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
+SQLITE_API const char *sqlite3_libversion(void){ return sqlite3_version; }
+SQLITE_API int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
+SQLITE_API int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** If the following function pointer is not NULL and if
+** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
+** I/O active are written using this function.  These messages
+** are intended for debugging activity only.
+*/
+SQLITE_PRIVATE void (*sqlite3IoTrace)(const char*, ...) = 0;
+#endif
+
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** temporary files.
+**
+** See also the "PRAGMA temp_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_temp_directory = 0;
+
+/*
+** Routine needed to support the testcase() macro.
+*/
+#ifdef SQLITE_COVERAGE_TEST
+SQLITE_PRIVATE void sqlite3Coverage(int x){
+  static int dummy = 0;
+  dummy += x;
+}
+#endif
+
+
+/*
+** Return true if the buffer z[0..n-1] contains all spaces.
+*/
+static int allSpaces(const char *z, int n){
+  while( n>0 && z[n-1]==' ' ){ n--; }
+  return n==0;
+}
+
+/*
+** This is the default collating function named "BINARY" which is always
+** available.
+**
+** If the padFlag argument is not NULL then space padding at the end
+** of strings is ignored.  This implements the RTRIM collation.
+*/
+static int binCollFunc(
+  void *padFlag,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int rc, n;
+  n = nKey1<nKey2 ? nKey1 : nKey2;
+  rc = memcmp(pKey1, pKey2, n);
+  if( rc==0 ){
+    if( padFlag
+     && allSpaces(((char*)pKey1)+n, nKey1-n)
+     && allSpaces(((char*)pKey2)+n, nKey2-n)
+    ){
+      /* Leave rc unchanged at 0 */
+    }else{
+      rc = nKey1 - nKey2;
+    }
+  }
+  return rc;
+}
+
+/*
+** Another built-in collating sequence: NOCASE. 
+**
+** This collating sequence is intended to be used for "case independant
+** comparison". SQLite's knowledge of upper and lower case equivalents
+** extends only to the 26 characters used in the English language.
+**
+** At the moment there is only a UTF-8 implementation.
+*/
+static int nocaseCollatingFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int r = sqlite3StrNICmp(
+      (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
+  if( 0==r ){
+    r = nKey1-nKey2;
+  }
+  return r;
+}
+
+/*
+** Return the ROWID of the most recent insert
+*/
+SQLITE_API sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
+  return db->lastRowid;
+}
+
+/*
+** Return the number of changes in the most recent call to sqlite3_exec().
+*/
+SQLITE_API int sqlite3_changes(sqlite3 *db){
+  return db->nChange;
+}
+
+/*
+** Return the number of changes since the database handle was opened.
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3 *db){
+  return db->nTotalChange;
+}
+
+/*
+** Close an existing SQLite database
+*/
+SQLITE_API int sqlite3_close(sqlite3 *db){
+  HashElem *i;
+  int j;
+
+  if( !db ){
+    return SQLITE_OK;
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE;
+  }
+  sqlite3_mutex_enter(db->mutex);
+
+#ifdef SQLITE_SSE
+  {
+    extern void sqlite3SseCleanup(sqlite3*);
+    sqlite3SseCleanup(db);
+  }
+#endif 
+
+  sqlite3ResetInternalSchema(db, 0);
+
+  /* If a transaction is open, the ResetInternalSchema() call above
+  ** will not have called the xDisconnect() method on any virtual
+  ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
+  ** call will do so. We need to do this before the check for active
+  ** SQL statements below, as the v-table implementation may be storing
+  ** some prepared statements internally.
+  */
+  sqlite3VtabRollback(db);
+
+  /* If there are any outstanding VMs, return SQLITE_BUSY. */
+  if( db->pVdbe ){
+    sqlite3Error(db, SQLITE_BUSY, 
+        "Unable to close due to unfinalised statements");
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_BUSY;
+  }
+  assert( sqlite3SafetyCheckSickOrOk(db) );
+
+  for(j=0; j<db->nDb; j++){
+    struct Db *pDb = &db->aDb[j];
+    if( pDb->pBt ){
+      sqlite3BtreeClose(pDb->pBt);
+      pDb->pBt = 0;
+      if( j!=1 ){
+        pDb->pSchema = 0;
+      }
+    }
+  }
+  sqlite3ResetInternalSchema(db, 0);
+  assert( db->nDb<=2 );
+  assert( db->aDb==db->aDbStatic );
+  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
+    FuncDef *pFunc, *pNext;
+    for(pFunc = (FuncDef*)sqliteHashData(i); pFunc; pFunc=pNext){
+      pNext = pFunc->pNext;
+      sqlite3_free(pFunc);
+    }
+  }
+
+  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
+    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
+    /* Invoke any destructors registered for collation sequence user data. */
+    for(j=0; j<3; j++){
+      if( pColl[j].xDel ){
+        pColl[j].xDel(pColl[j].pUser);
+      }
+    }
+    sqlite3_free(pColl);
+  }
+  sqlite3HashClear(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
+    Module *pMod = (Module *)sqliteHashData(i);
+    if( pMod->xDestroy ){
+      pMod->xDestroy(pMod->pAux);
+    }
+    sqlite3_free(pMod);
+  }
+  sqlite3HashClear(&db->aModule);
+#endif
+
+  sqlite3HashClear(&db->aFunc);
+  sqlite3Error(db, SQLITE_OK, 0); /* Deallocates any cached error strings. */
+  if( db->pErr ){
+    sqlite3ValueFree(db->pErr);
+  }
+  sqlite3CloseExtensions(db);
+
+  db->magic = SQLITE_MAGIC_ERROR;
+
+  /* The temp-database schema is allocated differently from the other schema
+  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
+  ** So it needs to be freed here. Todo: Why not roll the temp schema into
+  ** the same sqliteMalloc() as the one that allocates the database 
+  ** structure?
+  */
+  sqlite3_free(db->aDb[1].pSchema);
+  sqlite3_mutex_leave(db->mutex);
+  db->magic = SQLITE_MAGIC_CLOSED;
+  sqlite3_mutex_free(db->mutex);
+  sqlite3_free(db);
+  return SQLITE_OK;
+}
+
+/*
+** Rollback all database files.
+*/
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db){
+  int i;
+  int inTrans = 0;
+  assert( sqlite3_mutex_held(db->mutex) );
+  sqlite3FaultBeginBenign(SQLITE_FAULTINJECTOR_MALLOC);
+  for(i=0; i<db->nDb; i++){
+    if( db->aDb[i].pBt ){
+      if( sqlite3BtreeIsInTrans(db->aDb[i].pBt) ){
+        inTrans = 1;
+      }
+      sqlite3BtreeRollback(db->aDb[i].pBt);
+      db->aDb[i].inTrans = 0;
+    }
+  }
+  sqlite3VtabRollback(db);
+  sqlite3FaultEndBenign(SQLITE_FAULTINJECTOR_MALLOC);
+
+  if( db->flags&SQLITE_InternChanges ){
+    sqlite3ExpirePreparedStatements(db);
+    sqlite3ResetInternalSchema(db, 0);
+  }
+
+  /* If one has been configured, invoke the rollback-hook callback */
+  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
+    db->xRollbackCallback(db->pRollbackArg);
+  }
+}
+
+/*
+** Return a static string that describes the kind of error specified in the
+** argument.
+*/
+SQLITE_PRIVATE const char *sqlite3ErrStr(int rc){
+  const char *z;
+  switch( rc & 0xff ){
+    case SQLITE_ROW:
+    case SQLITE_DONE:
+    case SQLITE_OK:         z = "not an error";                          break;
+    case SQLITE_ERROR:      z = "SQL logic error or missing database";   break;
+    case SQLITE_PERM:       z = "access permission denied";              break;
+    case SQLITE_ABORT:      z = "callback requested query abort";        break;
+    case SQLITE_BUSY:       z = "database is locked";                    break;
+    case SQLITE_LOCKED:     z = "database table is locked";              break;
+    case SQLITE_NOMEM:      z = "out of memory";                         break;
+    case SQLITE_READONLY:   z = "attempt to write a readonly database";  break;
+    case SQLITE_INTERRUPT:  z = "interrupted";                           break;
+    case SQLITE_IOERR:      z = "disk I/O error";                        break;
+    case SQLITE_CORRUPT:    z = "database disk image is malformed";      break;
+    case SQLITE_FULL:       z = "database or disk is full";              break;
+    case SQLITE_CANTOPEN:   z = "unable to open database file";          break;
+    case SQLITE_EMPTY:      z = "table contains no data";                break;
+    case SQLITE_SCHEMA:     z = "database schema has changed";           break;
+    case SQLITE_TOOBIG:     z = "String or BLOB exceeded size limit";    break;
+    case SQLITE_CONSTRAINT: z = "constraint failed";                     break;
+    case SQLITE_MISMATCH:   z = "datatype mismatch";                     break;
+    case SQLITE_MISUSE:     z = "library routine called out of sequence";break;
+    case SQLITE_NOLFS:      z = "large file support is disabled";        break;
+    case SQLITE_AUTH:       z = "authorization denied";                  break;
+    case SQLITE_FORMAT:     z = "auxiliary database format error";       break;
+    case SQLITE_RANGE:      z = "bind or column index out of range";     break;
+    case SQLITE_NOTADB:     z = "file is encrypted or is not a database";break;
+    default:                z = "unknown error";                         break;
+  }
+  return z;
+}
+
+/*
+** This routine implements a busy callback that sleeps and tries
+** again until a timeout value is reached.  The timeout value is
+** an integer number of milliseconds passed in as the first
+** argument.
+*/
+static int sqliteDefaultBusyCallback(
+ void *ptr,               /* Database connection */
+ int count                /* Number of times table has been busy */
+){
+#if OS_WIN || (defined(HAVE_USLEEP) && HAVE_USLEEP)
+  static const u8 delays[] =
+     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
+  static const u8 totals[] =
+     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
+# define NDELAY (sizeof(delays)/sizeof(delays[0]))
+  sqlite3 *db = (sqlite3 *)ptr;
+  int timeout = db->busyTimeout;
+  int delay, prior;
+
+  assert( count>=0 );
+  if( count < NDELAY ){
+    delay = delays[count];
+    prior = totals[count];
+  }else{
+    delay = delays[NDELAY-1];
+    prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
+  }
+  if( prior + delay > timeout ){
+    delay = timeout - prior;
+    if( delay<=0 ) return 0;
+  }
+  sqlite3OsSleep(db->pVfs, delay*1000);
+  return 1;
+#else
+  sqlite3 *db = (sqlite3 *)ptr;
+  int timeout = ((sqlite3 *)ptr)->busyTimeout;
+  if( (count+1)*1000 > timeout ){
+    return 0;
+  }
+  sqlite3OsSleep(db->pVfs, 1000000);
+  return 1;
+#endif
+}
+
+/*
+** Invoke the given busy handler.
+**
+** This routine is called when an operation failed with a lock.
+** If this routine returns non-zero, the lock is retried.  If it
+** returns 0, the operation aborts with an SQLITE_BUSY error.
+*/
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler *p){
+  int rc;
+  if( p==0 || p->xFunc==0 || p->nBusy<0 ) return 0;
+  rc = p->xFunc(p->pArg, p->nBusy);
+  if( rc==0 ){
+    p->nBusy = -1;
+  }else{
+    p->nBusy++;
+  }
+  return rc; 
+}
+
+/*
+** This routine sets the busy callback for an Sqlite database to the
+** given callback function with the given argument.
+*/
+SQLITE_API int sqlite3_busy_handler(
+  sqlite3 *db,
+  int (*xBusy)(void*,int),
+  void *pArg
+){
+  sqlite3_mutex_enter(db->mutex);
+  db->busyHandler.xFunc = xBusy;
+  db->busyHandler.pArg = pArg;
+  db->busyHandler.nBusy = 0;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+/*
+** This routine sets the progress callback for an Sqlite database to the
+** given callback function with the given argument. The progress callback will
+** be invoked every nOps opcodes.
+*/
+SQLITE_API void sqlite3_progress_handler(
+  sqlite3 *db, 
+  int nOps,
+  int (*xProgress)(void*), 
+  void *pArg
+){
+  if( sqlite3SafetyCheckOk(db) ){
+    sqlite3_mutex_enter(db->mutex);
+    if( nOps>0 ){
+      db->xProgress = xProgress;
+      db->nProgressOps = nOps;
+      db->pProgressArg = pArg;
+    }else{
+      db->xProgress = 0;
+      db->nProgressOps = 0;
+      db->pProgressArg = 0;
+    }
+    sqlite3_mutex_leave(db->mutex);
+  }
+}
+#endif
+
+
+/*
+** This routine installs a default busy handler that waits for the
+** specified number of milliseconds before returning 0.
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3 *db, int ms){
+  if( ms>0 ){
+    db->busyTimeout = ms;
+    sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
+  }else{
+    sqlite3_busy_handler(db, 0, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Cause any pending operation to stop at its earliest opportunity.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3 *db){
+  if( sqlite3SafetyCheckOk(db) ){
+    db->u1.isInterrupted = 1;
+  }
+}
+
+
+/*
+** This function is exactly the same as sqlite3_create_function(), except
+** that it is designed to be called by internal code. The difference is
+** that if a malloc() fails in sqlite3_create_function(), an error code
+** is returned and the mallocFailed flag cleared. 
+*/
+SQLITE_PRIVATE int sqlite3CreateFunc(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int enc,
+  void *pUserData,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*)
+){
+  FuncDef *p;
+  int nName;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( zFunctionName==0 ||
+      (xFunc && (xFinal || xStep)) || 
+      (!xFunc && (xFinal && !xStep)) ||
+      (!xFunc && (!xFinal && xStep)) ||
+      (nArg<-1 || nArg>127) ||
+      (255<(nName = strlen(zFunctionName))) ){
+    sqlite3Error(db, SQLITE_ERROR, "bad parameters");
+    return SQLITE_ERROR;
+  }
+  
+#ifndef SQLITE_OMIT_UTF16
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  **
+  ** If SQLITE_ANY is specified, add three versions of the function
+  ** to the hash table.
+  */
+  if( enc==SQLITE_UTF16 ){
+    enc = SQLITE_UTF16NATIVE;
+  }else if( enc==SQLITE_ANY ){
+    int rc;
+    rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8,
+         pUserData, xFunc, xStep, xFinal);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE,
+          pUserData, xFunc, xStep, xFinal);
+    }
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    enc = SQLITE_UTF16BE;
+  }
+#else
+  enc = SQLITE_UTF8;
+#endif
+  
+  /* Check if an existing function is being overridden or deleted. If so,
+  ** and there are active VMs, then return SQLITE_BUSY. If a function
+  ** is being overridden/deleted but there are no active VMs, allow the
+  ** operation to continue but invalidate all precompiled statements.
+  */
+  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 0);
+  if( p && p->iPrefEnc==enc && p->nArg==nArg ){
+    if( db->activeVdbeCnt ){
+      sqlite3Error(db, SQLITE_BUSY, 
+        "Unable to delete/modify user-function due to active statements");
+      assert( !db->mallocFailed );
+      return SQLITE_BUSY;
+    }else{
+      sqlite3ExpirePreparedStatements(db);
+    }
+  }
+
+  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 1);
+  assert(p || db->mallocFailed);
+  if( !p ){
+    return SQLITE_NOMEM;
+  }
+  p->flags = 0;
+  p->xFunc = xFunc;
+  p->xStep = xStep;
+  p->xFinalize = xFinal;
+  p->pUserData = pUserData;
+  p->nArg = nArg;
+  return SQLITE_OK;
+}
+
+/*
+** Create new user functions.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*)
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3CreateFunc(db, zFunctionName, nArg, enc, p, xFunc, xStep, xFinal);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *p,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+){
+  int rc;
+  char *zFunc8;
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1);
+  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal);
+  sqlite3_free(zFunc8);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif
+
+
+/*
+** Declare that a function has been overloaded by a virtual table.
+**
+** If the function already exists as a regular global function, then
+** this routine is a no-op.  If the function does not exist, then create
+** a new one that always throws a run-time error.  
+**
+** When virtual tables intend to provide an overloaded function, they
+** should call this routine to make sure the global function exists.
+** A global function must exist in order for name resolution to work
+** properly.
+*/
+SQLITE_API int sqlite3_overload_function(
+  sqlite3 *db,
+  const char *zName,
+  int nArg
+){
+  int nName = strlen(zName);
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
+    sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
+                      0, sqlite3InvalidFunction, 0, 0);
+  }
+  rc = sqlite3ApiExit(db, SQLITE_OK);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_TRACE
+/*
+** Register a trace function.  The pArg from the previously registered trace
+** is returned.  
+**
+** A NULL trace function means that no tracing is executes.  A non-NULL
+** trace is a pointer to a function that is invoked at the start of each
+** SQL statement.
+*/
+SQLITE_API void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
+  void *pOld;
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pTraceArg;
+  db->xTrace = xTrace;
+  db->pTraceArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+/*
+** Register a profile function.  The pArg from the previously registered 
+** profile function is returned.  
+**
+** A NULL profile function means that no profiling is executes.  A non-NULL
+** profile is a pointer to a function that is invoked at the conclusion of
+** each SQL statement that is run.
+*/
+SQLITE_API void *sqlite3_profile(
+  sqlite3 *db,
+  void (*xProfile)(void*,const char*,sqlite_uint64),
+  void *pArg
+){
+  void *pOld;
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pProfileArg;
+  db->xProfile = xProfile;
+  db->pProfileArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+#endif /* SQLITE_OMIT_TRACE */
+
+/*** EXPERIMENTAL ***
+**
+** Register a function to be invoked when a transaction comments.
+** If the invoked function returns non-zero, then the commit becomes a
+** rollback.
+*/
+SQLITE_API void *sqlite3_commit_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  int (*xCallback)(void*),  /* Function to invoke on each commit */
+  void *pArg                /* Argument to the function */
+){
+  void *pOld;
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pCommitArg;
+  db->xCommitCallback = xCallback;
+  db->pCommitArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+
+/*
+** Register a callback to be invoked each time a row is updated,
+** inserted or deleted using this database connection.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pUpdateArg;
+  db->xUpdateCallback = xCallback;
+  db->pUpdateArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is rolled
+** back by this database connection.
+*/
+SQLITE_API void *sqlite3_rollback_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*), /* Callback function */
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pRollbackArg;
+  db->xRollbackCallback = xCallback;
+  db->pRollbackArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+/*
+** This routine is called to create a connection to a database BTree
+** driver.  If zFilename is the name of a file, then that file is
+** opened and used.  If zFilename is the magic name ":memory:" then
+** the database is stored in memory (and is thus forgotten as soon as
+** the connection is closed.)  If zFilename is NULL then the database
+** is a "virtual" database for transient use only and is deleted as
+** soon as the connection is closed.
+**
+** A virtual database can be either a disk file (that is automatically
+** deleted when the file is closed) or it an be held entirely in memory,
+** depending on the values of the TEMP_STORE compile-time macro and the
+** db->temp_store variable, according to the following chart:
+**
+**       TEMP_STORE     db->temp_store     Location of temporary database
+**       ----------     --------------     ------------------------------
+**           0               any             file
+**           1                1              file
+**           1                2              memory
+**           1                0              file
+**           2                1              file
+**           2                2              memory
+**           2                0              memory
+**           3               any             memory
+*/
+SQLITE_PRIVATE int sqlite3BtreeFactory(
+  const sqlite3 *db,        /* Main database when opening aux otherwise 0 */
+  const char *zFilename,    /* Name of the file containing the BTree database */
+  int omitJournal,          /* if TRUE then do not journal this file */
+  int nCache,               /* How many pages in the page cache */
+  int vfsFlags,             /* Flags passed through to vfsOpen */
+  Btree **ppBtree           /* Pointer to new Btree object written here */
+){
+  int btFlags = 0;
+  int rc;
+  
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( ppBtree != 0);
+  if( omitJournal ){
+    btFlags |= BTREE_OMIT_JOURNAL;
+  }
+  if( db->flags & SQLITE_NoReadlock ){
+    btFlags |= BTREE_NO_READLOCK;
+  }
+  if( zFilename==0 ){
+#if TEMP_STORE==0
+    /* Do nothing */
+#endif
+#ifndef SQLITE_OMIT_MEMORYDB
+#if TEMP_STORE==1
+    if( db->temp_store==2 ) zFilename = ":memory:";
+#endif
+#if TEMP_STORE==2
+    if( db->temp_store!=1 ) zFilename = ":memory:";
+#endif
+#if TEMP_STORE==3
+    zFilename = ":memory:";
+#endif
+#endif /* SQLITE_OMIT_MEMORYDB */
+  }
+
+  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (zFilename==0 || *zFilename==0) ){
+    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
+  }
+  rc = sqlite3BtreeOpen(zFilename, (sqlite3 *)db, ppBtree, btFlags, vfsFlags);
+  if( rc==SQLITE_OK ){
+    sqlite3BtreeSetCacheSize(*ppBtree, nCache);
+  }
+  return rc;
+}
+
+/*
+** Return UTF-8 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const char *sqlite3_errmsg(sqlite3 *db){
+  const char *z;
+  if( !db ){
+    return sqlite3ErrStr(SQLITE_NOMEM);
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) || db->errCode==SQLITE_MISUSE ){
+    return sqlite3ErrStr(SQLITE_MISUSE);
+  }
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  z = (char*)sqlite3_value_text(db->pErr);
+  if( z==0 ){
+    z = sqlite3ErrStr(db->errCode);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Return UTF-16 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const void *sqlite3_errmsg16(sqlite3 *db){
+  /* Because all the characters in the string are in the unicode
+  ** range 0x00-0xFF, if we pad the big-endian string with a 
+  ** zero byte, we can obtain the little-endian string with
+  ** &big_endian[1].
+  */
+  static const char outOfMemBe[] = {
+    0, 'o', 0, 'u', 0, 't', 0, ' ', 
+    0, 'o', 0, 'f', 0, ' ', 
+    0, 'm', 0, 'e', 0, 'm', 0, 'o', 0, 'r', 0, 'y', 0, 0, 0
+  };
+  static const char misuseBe [] = {
+    0, 'l', 0, 'i', 0, 'b', 0, 'r', 0, 'a', 0, 'r', 0, 'y', 0, ' ', 
+    0, 'r', 0, 'o', 0, 'u', 0, 't', 0, 'i', 0, 'n', 0, 'e', 0, ' ', 
+    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
+    0, 'o', 0, 'u', 0, 't', 0, ' ', 
+    0, 'o', 0, 'f', 0, ' ', 
+    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
+  };
+
+  const void *z;
+  if( !db ){
+    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) || db->errCode==SQLITE_MISUSE ){
+    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
+  }
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  z = sqlite3_value_text16(db->pErr);
+  if( z==0 ){
+    sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
+         SQLITE_UTF8, SQLITE_STATIC);
+    z = sqlite3_value_text16(db->pErr);
+  }
+  sqlite3ApiExit(0, 0);
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the most recent error code generated by an SQLite routine. If NULL is
+** passed to this function, we assume a malloc() failed during sqlite3_open().
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db){
+  if( db && !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE;
+  }
+  if( !db || db->mallocFailed ){
+    return SQLITE_NOMEM;
+  }
+  return db->errCode & db->errMask;
+}
+
+/*
+** Create a new collating function for database "db".  The name is zName
+** and the encoding is enc.
+*/
+static int createCollation(
+  sqlite3* db, 
+  const char *zName, 
+  int enc, 
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  CollSeq *pColl;
+  int enc2;
+  
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  */
+  enc2 = enc & ~SQLITE_UTF16_ALIGNED;
+  if( enc2==SQLITE_UTF16 ){
+    enc2 = SQLITE_UTF16NATIVE;
+  }
+
+  if( (enc2&~3)!=0 ){
+    sqlite3Error(db, SQLITE_ERROR, "unknown encoding");
+    return SQLITE_ERROR;
+  }
+
+  /* Check if this call is removing or replacing an existing collation 
+  ** sequence. If so, and there are active VMs, return busy. If there
+  ** are no active VMs, invalidate any pre-compiled statements.
+  */
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, strlen(zName), 0);
+  if( pColl && pColl->xCmp ){
+    if( db->activeVdbeCnt ){
+      sqlite3Error(db, SQLITE_BUSY, 
+        "Unable to delete/modify collation sequence due to active statements");
+      return SQLITE_BUSY;
+    }
+    sqlite3ExpirePreparedStatements(db);
+
+    /* If collation sequence pColl was created directly by a call to
+    ** sqlite3_create_collation, and not generated by synthCollSeq(),
+    ** then any copies made by synthCollSeq() need to be invalidated.
+    ** Also, collation destructor - CollSeq.xDel() - function may need
+    ** to be called.
+    */ 
+    if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
+      CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName, strlen(zName));
+      int j;
+      for(j=0; j<3; j++){
+        CollSeq *p = &aColl[j];
+        if( p->enc==pColl->enc ){
+          if( p->xDel ){
+            p->xDel(p->pUser);
+          }
+          p->xCmp = 0;
+        }
+      }
+    }
+  }
+
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, strlen(zName), 1);
+  if( pColl ){
+    pColl->xCmp = xCompare;
+    pColl->pUser = pCtx;
+    pColl->xDel = xDel;
+    pColl->enc = enc2 | (enc & SQLITE_UTF16_ALIGNED);
+  }
+  sqlite3Error(db, SQLITE_OK, 0);
+  return SQLITE_OK;
+}
+
+
+/*
+** This array defines hard upper bounds on limit values.  The
+** initializer must be kept in sync with the SQLITE_LIMIT_*
+** #defines in sqlite3.h.
+*/
+static const int aHardLimit[] = {
+  SQLITE_MAX_LENGTH,
+  SQLITE_MAX_SQL_LENGTH,
+  SQLITE_MAX_COLUMN,
+  SQLITE_MAX_EXPR_DEPTH,
+  SQLITE_MAX_COMPOUND_SELECT,
+  SQLITE_MAX_VDBE_OP,
+  SQLITE_MAX_FUNCTION_ARG,
+  SQLITE_MAX_ATTACHED,
+  SQLITE_MAX_LIKE_PATTERN_LENGTH,
+  SQLITE_MAX_VARIABLE_NUMBER,
+};
+
+/*
+** Make sure the hard limits are set to reasonable values
+*/
+#if SQLITE_MAX_LENGTH<100
+# error SQLITE_MAX_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH<100
+# error SQLITE_MAX_SQL_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
+# error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
+#endif
+#if SQLITE_MAX_COMPOUND_SELECT<2
+# error SQLITE_MAX_COMPOUND_SELECT must be at least 2
+#endif
+#if SQLITE_MAX_VDBE_OP<40
+# error SQLITE_MAX_VDBE_OP must be at least 40
+#endif
+#if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>255
+# error SQLITE_MAX_FUNCTION_ARG must be between 0 and 255
+#endif
+#if SQLITE_MAX_ATTACH<0 || SQLITE_MAX_ATTACH>30
+# error SQLITE_MAX_ATTACH must be between 0 and 30
+#endif
+#if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
+# error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
+#endif
+#if SQLITE_MAX_VARIABLE_NUMBER<1
+# error SQLITE_MAX_VARIABLE_NUMBER must be at least 1
+#endif
+
+
+/*
+** Change the value of a limit.  Report the old value.
+** If an invalid limit index is supplied, report -1.
+** Make no changes but still report the old value if the
+** new limit is negative.
+**
+** A new lower limit does not shrink existing constructs.
+** It merely prevents new constructs that exceed the limit
+** from forming.
+*/
+SQLITE_API int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
+  int oldLimit;
+  if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
+    return -1;
+  }
+  oldLimit = db->aLimit[limitId];
+  if( newLimit>=0 ){
+    if( newLimit>aHardLimit[limitId] ){
+      newLimit = aHardLimit[limitId];
+    }
+    db->aLimit[limitId] = newLimit;
+  }
+  return oldLimit;
+}
+
+/*
+** This routine does the work of opening a database on behalf of
+** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"  
+** is UTF-8 encoded.
+*/
+static int openDatabase(
+  const char *zFilename, /* Database filename UTF-8 encoded */
+  sqlite3 **ppDb,        /* OUT: Returned database handle */
+  unsigned flags,        /* Operational flags */
+  const char *zVfs       /* Name of the VFS to use */
+){
+  sqlite3 *db;
+  int rc;
+  CollSeq *pColl;
+
+  /* Remove harmful bits from the flags parameter */
+  flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
+               SQLITE_OPEN_MAIN_DB |
+               SQLITE_OPEN_TEMP_DB | 
+               SQLITE_OPEN_TRANSIENT_DB | 
+               SQLITE_OPEN_MAIN_JOURNAL | 
+               SQLITE_OPEN_TEMP_JOURNAL | 
+               SQLITE_OPEN_SUBJOURNAL | 
+               SQLITE_OPEN_MASTER_JOURNAL
+             );
+
+  /* Allocate the sqlite data structure */
+  db = sqlite3MallocZero( sizeof(sqlite3) );
+  if( db==0 ) goto opendb_out;
+  db->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
+  if( db->mutex==0 ){
+    sqlite3_free(db);
+    db = 0;
+    goto opendb_out;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = 0xff;
+  db->priorNewRowid = 0;
+  db->nDb = 2;
+  db->magic = SQLITE_MAGIC_BUSY;
+  db->aDb = db->aDbStatic;
+  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
+  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
+  db->autoCommit = 1;
+  db->nextAutovac = -1;
+  db->nextPagesize = 0;
+  db->flags |= SQLITE_ShortColNames
+#if SQLITE_DEFAULT_FILE_FORMAT<4
+                 | SQLITE_LegacyFileFmt
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+                 | SQLITE_LoadExtension
+#endif
+      ;
+  sqlite3HashInit(&db->aFunc, SQLITE_HASH_STRING, 0);
+  sqlite3HashInit(&db->aCollSeq, SQLITE_HASH_STRING, 0);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3HashInit(&db->aModule, SQLITE_HASH_STRING, 0);
+#endif
+
+  db->pVfs = sqlite3_vfs_find(zVfs);
+  if( !db->pVfs ){
+    rc = SQLITE_ERROR;
+    db->magic = SQLITE_MAGIC_SICK;
+    sqlite3Error(db, rc, "no such vfs: %s", zVfs);
+    goto opendb_out;
+  }
+
+  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
+  ** and UTF-16, so add a version for each to avoid any unnecessary
+  ** conversions. The only error that can occur here is a malloc() failure.
+  */
+  createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
+  createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
+  createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
+  createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
+  if( db->mallocFailed ){
+    db->magic = SQLITE_MAGIC_SICK;
+    goto opendb_out;
+  }
+  db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
+  assert( db->pDfltColl!=0 );
+
+  /* Also add a UTF-8 case-insensitive collation sequence. */
+  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
+
+  /* Set flags on the built-in collating sequences */
+  db->pDfltColl->type = SQLITE_COLL_BINARY;
+  pColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "NOCASE", 6, 0);
+  if( pColl ){
+    pColl->type = SQLITE_COLL_NOCASE;
+  }
+
+  /* Open the backend database driver */
+  db->openFlags = flags;
+  rc = sqlite3BtreeFactory(db, zFilename, 0, SQLITE_DEFAULT_CACHE_SIZE, 
+                           flags | SQLITE_OPEN_MAIN_DB,
+                           &db->aDb[0].pBt);
+  if( rc!=SQLITE_OK ){
+    sqlite3Error(db, rc, 0);
+    db->magic = SQLITE_MAGIC_SICK;
+    goto opendb_out;
+  }
+  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
+  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
+
+
+  /* The default safety_level for the main database is 'full'; for the temp
+  ** database it is 'NONE'. This matches the pager layer defaults.  
+  */
+  db->aDb[0].zName = "main";
+  db->aDb[0].safety_level = 3;
+#ifndef SQLITE_OMIT_TEMPDB
+  db->aDb[1].zName = "temp";
+  db->aDb[1].safety_level = 1;
+#endif
+
+  db->magic = SQLITE_MAGIC_OPEN;
+  if( db->mallocFailed ){
+    goto opendb_out;
+  }
+
+  /* Register all built-in functions, but do not attempt to read the
+  ** database schema yet. This is delayed until the first time the database
+  ** is accessed.
+  */
+  sqlite3Error(db, SQLITE_OK, 0);
+  sqlite3RegisterBuiltinFunctions(db);
+
+  /* Load automatic extensions - extensions that have been registered
+  ** using the sqlite3_automatic_extension() API.
+  */
+  (void)sqlite3AutoLoadExtensions(db);
+  if( sqlite3_errcode(db)!=SQLITE_OK ){
+    goto opendb_out;
+  }
+
+#ifdef SQLITE_ENABLE_FTS1
+  if( !db->mallocFailed ){
+    extern int sqlite3Fts1Init(sqlite3*);
+    rc = sqlite3Fts1Init(db);
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_FTS2
+  if( !db->mallocFailed && rc==SQLITE_OK ){
+    extern int sqlite3Fts2Init(sqlite3*);
+    rc = sqlite3Fts2Init(db);
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_FTS3
+  if( !db->mallocFailed && rc==SQLITE_OK ){
+    rc = sqlite3Fts3Init(db);
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_ICU
+  if( !db->mallocFailed && rc==SQLITE_OK ){
+    extern int sqlite3IcuInit(sqlite3*);
+    rc = sqlite3IcuInit(db);
+  }
+#endif
+  sqlite3Error(db, rc, 0);
+
+  /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
+  ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
+  ** mode.  Doing nothing at all also makes NORMAL the default.
+  */
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
+  sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
+                          SQLITE_DEFAULT_LOCKING_MODE);
+#endif
+
+opendb_out:
+  if( db ){
+    assert( db->mutex!=0 );
+    sqlite3_mutex_leave(db->mutex);
+  }
+  if( SQLITE_NOMEM==(rc = sqlite3_errcode(db)) ){
+    sqlite3_close(db);
+    db = 0;
+  }
+  *ppDb = db;
+  return sqlite3ApiExit(0, rc);
+}
+
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open(
+  const char *zFilename, 
+  sqlite3 **ppDb 
+){
+  return openDatabase(zFilename, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+}
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+){
+  return openDatabase(filename, ppDb, flags, zVfs);
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open16(
+  const void *zFilename, 
+  sqlite3 **ppDb
+){
+  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
+  sqlite3_value *pVal;
+  int rc = SQLITE_NOMEM;
+
+  assert( zFilename );
+  assert( ppDb );
+  *ppDb = 0;
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zFilename8 ){
+    rc = openDatabase(zFilename8, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+    assert( *ppDb || rc==SQLITE_NOMEM );
+    if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
+      ENC(*ppDb) = SQLITE_UTF16NATIVE;
+    }
+  }
+  sqlite3ValueFree(pVal);
+
+  return sqlite3ApiExit(0, rc);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3* db, 
+  const char *zName, 
+  int enc, 
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  rc = createCollation(db, zName, enc, pCtx, xCompare, 0);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3* db, 
+  const char *zName, 
+  int enc, 
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  rc = createCollation(db, zName, enc, pCtx, xCompare, xDel);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3* db, 
+  const char *zName, 
+  int enc, 
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  int rc = SQLITE_OK;
+  char *zName8;
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zName8 = sqlite3Utf16to8(db, zName, -1);
+  if( zName8 ){
+    rc = createCollation(db, zName8, enc, pCtx, xCompare, 0);
+    sqlite3_free(zName8);
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3 *db, 
+  void *pCollNeededArg, 
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
+){
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = xCollNeeded;
+  db->xCollNeeded16 = 0;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3 *db, 
+  void *pCollNeededArg, 
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
+){
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = 0;
+  db->xCollNeeded16 = xCollNeeded16;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_GLOBALRECOVER
+/*
+** This function is now an anachronism. It used to be used to recover from a
+** malloc() failure, but SQLite now does this automatically.
+*/
+SQLITE_API int sqlite3_global_recover(void){
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Test to see whether or not the database connection is in autocommit
+** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
+** by default.  Autocommit is disabled by a BEGIN statement and reenabled
+** by the next COMMIT or ROLLBACK.
+**
+******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3 *db){
+  return db->autoCommit;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** The following routine is subtituted for constant SQLITE_CORRUPT in
+** debugging builds.  This provides a way to set a breakpoint for when
+** corruption is first detected.
+*/
+SQLITE_PRIVATE int sqlite3Corrupt(void){
+  return SQLITE_CORRUPT;
+}
+#endif
+
+/*
+** This is a convenience routine that makes sure that all thread-specific
+** data for this thread has been deallocated.
+**
+** SQLite no longer uses thread-specific data so this routine is now a
+** no-op.  It is retained for historical compatibility.
+*/
+SQLITE_API void sqlite3_thread_cleanup(void){
+}
+
+/*
+** Return meta information about a specific column of a database table.
+** See comment in sqlite3.h (sqlite.h.in) for details.
+*/
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if colums is auto-increment */
+){
+  int rc;
+  char *zErrMsg = 0;
+  Table *pTab = 0;
+  Column *pCol = 0;
+  int iCol;
+
+  char const *zDataType = 0;
+  char const *zCollSeq = 0;
+  int notnull = 0;
+  int primarykey = 0;
+  int autoinc = 0;
+
+  /* Ensure the database schema has been loaded */
+  sqlite3_mutex_enter(db->mutex);
+  (void)sqlite3SafetyOn(db);
+  sqlite3BtreeEnterAll(db);
+  rc = sqlite3Init(db, &zErrMsg);
+  sqlite3BtreeLeaveAll(db);
+  if( SQLITE_OK!=rc ){
+    goto error_out;
+  }
+
+  /* Locate the table in question */
+  pTab = sqlite3FindTable(db, zTableName, zDbName);
+  if( !pTab || pTab->pSelect ){
+    pTab = 0;
+    goto error_out;
+  }
+
+  /* Find the column for which info is requested */
+  if( sqlite3IsRowid(zColumnName) ){
+    iCol = pTab->iPKey;
+    if( iCol>=0 ){
+      pCol = &pTab->aCol[iCol];
+    }
+  }else{
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      pCol = &pTab->aCol[iCol];
+      if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      pTab = 0;
+      goto error_out;
+    }
+  }
+
+  /* The following block stores the meta information that will be returned
+  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
+  ** and autoinc. At this point there are two possibilities:
+  ** 
+  **     1. The specified column name was rowid", "oid" or "_rowid_" 
+  **        and there is no explicitly declared IPK column. 
+  **
+  **     2. The table is not a view and the column name identified an 
+  **        explicitly declared column. Copy meta information from *pCol.
+  */ 
+  if( pCol ){
+    zDataType = pCol->zType;
+    zCollSeq = pCol->zColl;
+    notnull = (pCol->notNull?1:0);
+    primarykey  = (pCol->isPrimKey?1:0);
+    autoinc = ((pTab->iPKey==iCol && pTab->autoInc)?1:0);
+  }else{
+    zDataType = "INTEGER";
+    primarykey = 1;
+  }
+  if( !zCollSeq ){
+    zCollSeq = "BINARY";
+  }
+
+error_out:
+  (void)sqlite3SafetyOff(db);
+
+  /* Whether the function call succeeded or failed, set the output parameters
+  ** to whatever their local counterparts contain. If an error did occur,
+  ** this has the effect of zeroing all output parameters.
+  */
+  if( pzDataType ) *pzDataType = zDataType;
+  if( pzCollSeq ) *pzCollSeq = zCollSeq;
+  if( pNotNull ) *pNotNull = notnull;
+  if( pPrimaryKey ) *pPrimaryKey = primarykey;
+  if( pAutoinc ) *pAutoinc = autoinc;
+
+  if( SQLITE_OK==rc && !pTab ){
+    sqlite3SetString(&zErrMsg, "no such table column: ", zTableName, ".", 
+        zColumnName, 0);
+    rc = SQLITE_ERROR;
+  }
+  sqlite3Error(db, rc, (zErrMsg?"%s":0), zErrMsg);
+  sqlite3_free(zErrMsg);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+SQLITE_API int sqlite3_sleep(int ms){
+  sqlite3_vfs *pVfs;
+  int rc;
+  pVfs = sqlite3_vfs_find(0);
+
+  /* This function works in milliseconds, but the underlying OsSleep() 
+  ** API uses microseconds. Hence the 1000's.
+  */
+  rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
+  return rc;
+}
+
+/*
+** Enable or disable the extended result codes.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = onoff ? 0xffffffff : 0xff;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xFileControl method on a particular database.
+*/
+SQLITE_API int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
+  int rc = SQLITE_ERROR;
+  int iDb;
+  sqlite3_mutex_enter(db->mutex);
+  if( zDbName==0 ){
+    iDb = 0;
+  }else{
+    for(iDb=0; iDb<db->nDb; iDb++){
+      if( strcmp(db->aDb[iDb].zName, zDbName)==0 ) break;
+    }
+  }
+  if( iDb<db->nDb ){
+    Btree *pBtree = db->aDb[iDb].pBt;
+    if( pBtree ){
+      Pager *pPager;
+      sqlite3_file *fd;
+      sqlite3BtreeEnter(pBtree);
+      pPager = sqlite3BtreePager(pBtree);
+      assert( pPager!=0 );
+      fd = sqlite3PagerFile(pPager);
+      assert( fd!=0 );
+      if( fd->pMethods ){
+        rc = sqlite3OsFileControl(fd, op, pArg);
+      }
+      sqlite3BtreeLeave(pBtree);
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;   
+}
+
+/*
+** Interface to the testing logic.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...){
+  int rc = 0;
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+  va_list ap;
+  va_start(ap, op);
+  switch( op ){
+    /*
+    ** sqlite3_test_control(FAULT_CONFIG, fault_id, nDelay, nRepeat)
+    **
+    ** Configure a fault injector.  The specific fault injector is
+    ** identified by the fault_id argument.  (ex: SQLITE_FAULTINJECTOR_MALLOC)
+    ** The fault will occur after a delay of nDelay calls.  The fault
+    ** will repeat nRepeat times.
+    */
+    case SQLITE_TESTCTRL_FAULT_CONFIG: {
+      int id = va_arg(ap, int);
+      int nDelay = va_arg(ap, int);
+      int nRepeat = va_arg(ap, int);
+      sqlite3FaultConfig(id, nDelay, nRepeat);
+      break;
+    }
+
+    /*
+    ** sqlite3_test_control(FAULT_FAILURES, fault_id)
+    **
+    ** Return the number of faults (both hard and benign faults) that have
+    ** occurred since the injector identified by fault_id) was last configured.
+    */
+    case SQLITE_TESTCTRL_FAULT_FAILURES: {
+      int id = va_arg(ap, int);
+      rc = sqlite3FaultFailures(id);
+      break;
+    }
+
+    /*
+    ** sqlite3_test_control(FAULT_BENIGN_FAILURES, fault_id)
+    **
+    ** Return the number of benign faults that have occurred since the
+    ** injector identified by fault_id was last configured.
+    */
+    case SQLITE_TESTCTRL_FAULT_BENIGN_FAILURES: {
+      int id = va_arg(ap, int);
+      rc = sqlite3FaultBenignFailures(id);
+      break;
+    }
+
+    /*
+    ** sqlite3_test_control(FAULT_PENDING, fault_id)
+    **
+    ** Return the number of successes that will occur before the next
+    ** scheduled failure on fault injector fault_id.
+    ** If no failures are scheduled, return -1.
+    */
+    case SQLITE_TESTCTRL_FAULT_PENDING: {
+      int id = va_arg(ap, int);
+      rc = sqlite3FaultPending(id);
+      break;
+    }
+
+    /*
+    ** Save the current state of the PRNG.
+    */
+    case SQLITE_TESTCTRL_PRNG_SAVE: {
+      sqlite3PrngSaveState();
+      break;
+    }
+
+    /*
+    ** Restore the state of the PRNG to the last state saved using
+    ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
+    ** this verb acts like PRNG_RESET.
+    */
+    case SQLITE_TESTCTRL_PRNG_RESTORE: {
+      sqlite3PrngRestoreState();
+      break;
+    }
+
+    /*
+    ** Reset the PRNG back to its uninitialized state.  The next call
+    ** to sqlite3_randomness() will reseed the PRNG using a single call
+    ** to the xRandomness method of the default VFS.
+    */
+    case SQLITE_TESTCTRL_PRNG_RESET: {
+      sqlite3PrngResetState();
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(BITVEC_TEST, size, program)
+    **
+    ** Run a test against a Bitvec object of size.  The program argument
+    ** is an array of integers that defines the test.  Return -1 on a
+    ** memory allocation error, 0 on success, or non-zero for an error.
+    ** See the sqlite3BitvecBuiltinTest() for additional information.
+    */
+    case SQLITE_TESTCTRL_BITVEC_TEST: {
+      int sz = va_arg(ap, int);
+      int *aProg = va_arg(ap, int*);
+      rc = sqlite3BitvecBuiltinTest(sz, aProg);
+      break;
+    }
+  }
+  va_end(ap);
+#endif /* SQLITE_OMIT_BUILTIN_TEST */
+  return rc;
+}
+
+/************** End of main.c ************************************************/
+/************** Begin file fts3.c ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+
+/* TODO(shess) Consider exporting this comment to an HTML file or the
+** wiki.
+*/
+/* The full-text index is stored in a series of b+tree (-like)
+** structures called segments which map terms to doclists.  The
+** structures are like b+trees in layout, but are constructed from the
+** bottom up in optimal fashion and are not updatable.  Since trees
+** are built from the bottom up, things will be described from the
+** bottom up.
+**
+**
+**** Varints ****
+** The basic unit of encoding is a variable-length integer called a
+** varint.  We encode variable-length integers in little-endian order
+** using seven bits * per byte as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** and so on.
+**
+** This is identical to how sqlite encodes varints (see util.c).
+**
+**
+**** Document lists ****
+** A doclist (document list) holds a docid-sorted list of hits for a
+** given term.  Doclists hold docids, and can optionally associate
+** token positions and offsets with docids.
+**
+** A DL_POSITIONS_OFFSETS doclist is stored like this:
+**
+** array {
+**   varint docid;
+**   array {                (position list for column 0)
+**     varint position;     (delta from previous position plus POS_BASE)
+**     varint startOffset;  (delta from previous startOffset)
+**     varint endOffset;    (delta from startOffset)
+**   }
+**   array {
+**     varint POS_COLUMN;   (marks start of position list for new column)
+**     varint column;       (index of new column)
+**     array {
+**       varint position;   (delta from previous position plus POS_BASE)
+**       varint startOffset;(delta from previous startOffset)
+**       varint endOffset;  (delta from startOffset)
+**     }
+**   }
+**   varint POS_END;        (marks end of positions for this document.
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.  A "position" is an index of a token in the token stream
+** generated by the tokenizer, while an "offset" is a byte offset,
+** both based at 0.  Note that POS_END and POS_COLUMN occur in the
+** same logical place as the position element, and act as sentinals
+** ending a position list array.
+**
+** A DL_POSITIONS doclist omits the startOffset and endOffset
+** information.  A DL_DOCIDS doclist omits both the position and
+** offset information, becoming an array of varint-encoded docids.
+**
+** On-disk data is stored as type DL_DEFAULT, so we don't serialize
+** the type.  Due to how deletion is implemented in the segmentation
+** system, on-disk doclists MUST store at least positions.
+**
+**
+**** Segment leaf nodes ****
+** Segment leaf nodes store terms and doclists, ordered by term.  Leaf
+** nodes are written using LeafWriter, and read using LeafReader (to
+** iterate through a single leaf node's data) and LeavesReader (to
+** iterate through a segment's entire leaf layer).  Leaf nodes have
+** the format:
+**
+** varint iHeight;             (height from leaf level, always 0)
+** varint nTerm;               (length of first term)
+** char pTerm[nTerm];          (content of first term)
+** varint nDoclist;            (length of term's associated doclist)
+** char pDoclist[nDoclist];    (content of doclist)
+** array {
+**                             (further terms are delta-encoded)
+**   varint nPrefix;           (length of prefix shared with previous term)
+**   varint nSuffix;           (length of unshared suffix)
+**   char pTermSuffix[nSuffix];(unshared suffix of next term)
+**   varint nDoclist;          (length of term's associated doclist)
+**   char pDoclist[nDoclist];  (content of doclist)
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.
+**
+** Leaf nodes are broken into blocks which are stored contiguously in
+** the %_segments table in sorted order.  This means that when the end
+** of a node is reached, the next term is in the node with the next
+** greater node id.
+**
+** New data is spilled to a new leaf node when the current node
+** exceeds LEAF_MAX bytes (default 2048).  New data which itself is
+** larger than STANDALONE_MIN (default 1024) is placed in a standalone
+** node (a leaf node with a single term and doclist).  The goal of
+** these settings is to pack together groups of small doclists while
+** making it efficient to directly access large doclists.  The
+** assumption is that large doclists represent terms which are more
+** likely to be query targets.
+**
+** TODO(shess) It may be useful for blocking decisions to be more
+** dynamic.  For instance, it may make more sense to have a 2.5k leaf
+** node rather than splitting into 2k and .5k nodes.  My intuition is
+** that this might extend through 2x or 4x the pagesize.
+**
+**
+**** Segment interior nodes ****
+** Segment interior nodes store blockids for subtree nodes and terms
+** to describe what data is stored by the each subtree.  Interior
+** nodes are written using InteriorWriter, and read using
+** InteriorReader.  InteriorWriters are created as needed when
+** SegmentWriter creates new leaf nodes, or when an interior node
+** itself grows too big and must be split.  The format of interior
+** nodes:
+**
+** varint iHeight;           (height from leaf level, always >0)
+** varint iBlockid;          (block id of node's leftmost subtree)
+** optional {
+**   varint nTerm;           (length of first term)
+**   char pTerm[nTerm];      (content of first term)
+**   array {
+**                                (further terms are delta-encoded)
+**     varint nPrefix;            (length of shared prefix with previous term)
+**     varint nSuffix;            (length of unshared suffix)
+**     char pTermSuffix[nSuffix]; (unshared suffix of next term)
+**   }
+** }
+**
+** Here, optional { X } means an optional element, while array { X }
+** means zero or more occurrences of X, adjacent in memory.
+**
+** An interior node encodes n terms separating n+1 subtrees.  The
+** subtree blocks are contiguous, so only the first subtree's blockid
+** is encoded.  The subtree at iBlockid will contain all terms less
+** than the first term encoded (or all terms if no term is encoded).
+** Otherwise, for terms greater than or equal to pTerm[i] but less
+** than pTerm[i+1], the subtree for that term will be rooted at
+** iBlockid+i.  Interior nodes only store enough term data to
+** distinguish adjacent children (if the rightmost term of the left
+** child is "something", and the leftmost term of the right child is
+** "wicked", only "w" is stored).
+**
+** New data is spilled to a new interior node at the same height when
+** the current node exceeds INTERIOR_MAX bytes (default 2048).
+** INTERIOR_MIN_TERMS (default 7) keeps large terms from monopolizing
+** interior nodes and making the tree too skinny.  The interior nodes
+** at a given height are naturally tracked by interior nodes at
+** height+1, and so on.
+**
+**
+**** Segment directory ****
+** The segment directory in table %_segdir stores meta-information for
+** merging and deleting segments, and also the root node of the
+** segment's tree.
+**
+** The root node is the top node of the segment's tree after encoding
+** the entire segment, restricted to ROOT_MAX bytes (default 1024).
+** This could be either a leaf node or an interior node.  If the top
+** node requires more than ROOT_MAX bytes, it is flushed to %_segments
+** and a new root interior node is generated (which should always fit
+** within ROOT_MAX because it only needs space for 2 varints, the
+** height and the blockid of the previous root).
+**
+** The meta-information in the segment directory is:
+**   level               - segment level (see below)
+**   idx                 - index within level
+**                       - (level,idx uniquely identify a segment)
+**   start_block         - first leaf node
+**   leaves_end_block    - last leaf node
+**   end_block           - last block (including interior nodes)
+**   root                - contents of root node
+**
+** If the root node is a leaf node, then start_block,
+** leaves_end_block, and end_block are all 0.
+**
+**
+**** Segment merging ****
+** To amortize update costs, segments are groups into levels and
+** merged in matches.  Each increase in level represents exponentially
+** more documents.
+**
+** New documents (actually, document updates) are tokenized and
+** written individually (using LeafWriter) to a level 0 segment, with
+** incrementing idx.  When idx reaches MERGE_COUNT (default 16), all
+** level 0 segments are merged into a single level 1 segment.  Level 1
+** is populated like level 0, and eventually MERGE_COUNT level 1
+** segments are merged to a single level 2 segment (representing
+** MERGE_COUNT^2 updates), and so on.
+**
+** A segment merge traverses all segments at a given level in
+** parallel, performing a straightforward sorted merge.  Since segment
+** leaf nodes are written in to the %_segments table in order, this
+** merge traverses the underlying sqlite disk structures efficiently.
+** After the merge, all segment blocks from the merged level are
+** deleted.
+**
+** MERGE_COUNT controls how often we merge segments.  16 seems to be
+** somewhat of a sweet spot for insertion performance.  32 and 64 show
+** very similar performance numbers to 16 on insertion, though they're
+** a tiny bit slower (perhaps due to more overhead in merge-time
+** sorting).  8 is about 20% slower than 16, 4 about 50% slower than
+** 16, 2 about 66% slower than 16.
+**
+** At query time, high MERGE_COUNT increases the number of segments
+** which need to be scanned and merged.  For instance, with 100k docs
+** inserted:
+**
+**    MERGE_COUNT   segments
+**       16           25
+**        8           12
+**        4           10
+**        2            6
+**
+** This appears to have only a moderate impact on queries for very
+** frequent terms (which are somewhat dominated by segment merge
+** costs), and infrequent and non-existent terms still seem to be fast
+** even with many segments.
+**
+** TODO(shess) That said, it would be nice to have a better query-side
+** argument for MERGE_COUNT of 16.  Also, it is possible/likely that
+** optimizations to things like doclist merging will swing the sweet
+** spot around.
+**
+**
+**
+**** Handling of deletions and updates ****
+** Since we're using a segmented structure, with no docid-oriented
+** index into the term index, we clearly cannot simply update the term
+** index when a document is deleted or updated.  For deletions, we
+** write an empty doclist (varint(docid) varint(POS_END)), for updates
+** we simply write the new doclist.  Segment merges overwrite older
+** data for a particular docid with newer data, so deletes or updates
+** will eventually overtake the earlier data and knock it out.  The
+** query logic likewise merges doclists so that newer data knocks out
+** older data.
+**
+** TODO(shess) Provide a VACUUM type operation to clear out all
+** deletions and duplications.  This would basically be a forced merge
+** into a single segment.
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
+# define SQLITE_CORE 1
+#endif
+
+
+/************** Include fts3_hash.h in the middle of fts3.c ******************/
+/************** Begin file fts3_hash.h ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implemenation
+** used in SQLite.  We've modified it slightly to serve as a standalone
+** hash table implementation for the full-text indexing module.
+**
+*/
+#ifndef _FTS3_HASH_H_
+#define _FTS3_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct fts3Hash fts3Hash;
+typedef struct fts3HashElem fts3HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, many of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+*/
+struct fts3Hash {
+  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  fts3HashElem *first;    /* The first element of the array */
+  int htsize;             /* Number of buckets in the hash table */
+  struct _fts3ht {        /* the hash table */
+    int count;               /* Number of entries with this hash */
+    fts3HashElem *chain;     /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following 
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct fts3HashElem {
+  fts3HashElem *next, *prev; /* Next and previous elements in the table */
+  void *data;                /* Data associated with this element */
+  void *pKey; int nKey;      /* Key associated with this element */
+};
+
+/*
+** There are 2 different modes of operation for a hash table:
+**
+**   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is respected in comparisons.
+**
+**   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long. 
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.  
+*/
+#define FTS3_HASH_STRING    1
+#define FTS3_HASH_BINARY    2
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash*, int keytype, int copyKey);
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(fts3Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash*);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts3HashInit   sqlite3Fts3HashInit
+#define fts3HashInsert sqlite3Fts3HashInsert
+#define fts3HashFind   sqlite3Fts3HashFind
+#define fts3HashClear  sqlite3Fts3HashClear
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   fts3Hash h;
+**   fts3HashElem *p;
+**   ...
+**   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
+**     SomeStructure *pData = fts3HashData(p);
+**     // do something with pData
+**   }
+*/
+#define fts3HashFirst(H)  ((H)->first)
+#define fts3HashNext(E)   ((E)->next)
+#define fts3HashData(E)   ((E)->data)
+#define fts3HashKey(E)    ((E)->pKey)
+#define fts3HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts3HashCount(H)  ((H)->count)
+
+#endif /* _FTS3_HASH_H_ */
+
+/************** End of fts3_hash.h *******************************************/
+/************** Continuing where we left off in fts3.c ***********************/
+/************** Include fts3_tokenizer.h in the middle of fts3.c *************/
+/************** Begin file fts3_tokenizer.h **********************************/
+/*
+** 2006 July 10
+**
+** The author disclaims copyright to this source code.
+**
+*************************************************************************
+** Defines the interface to tokenizers used by fulltext-search.  There
+** are three basic components:
+**
+** sqlite3_tokenizer_module is a singleton defining the tokenizer
+** interface functions.  This is essentially the class structure for
+** tokenizers.
+**
+** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
+** including customization information defined at creation time.
+**
+** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
+** tokens from a particular input.
+*/
+#ifndef _FTS3_TOKENIZER_H_
+#define _FTS3_TOKENIZER_H_
+
+/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
+** If tokenizers are to be allowed to call sqlite3_*() functions, then
+** we will need a way to register the API consistently.
+*/
+
+/*
+** Structures used by the tokenizer interface. When a new tokenizer
+** implementation is registered, the caller provides a pointer to
+** an sqlite3_tokenizer_module containing pointers to the callback
+** functions that make up an implementation.
+**
+** When an fts3 table is created, it passes any arguments passed to
+** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
+** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
+** implementation. The xCreate() function in turn returns an 
+** sqlite3_tokenizer structure representing the specific tokenizer to
+** be used for the fts3 table (customized by the tokenizer clause arguments).
+**
+** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
+** method is called. It returns an sqlite3_tokenizer_cursor object
+** that may be used to tokenize a specific input buffer based on
+** the tokenization rules supplied by a specific sqlite3_tokenizer
+** object.
+*/
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+
+struct sqlite3_tokenizer_module {
+
+  /*
+  ** Structure version. Should always be set to 0.
+  */
+  int iVersion;
+
+  /*
+  ** Create a new tokenizer. The values in the argv[] array are the
+  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
+  ** TABLE statement that created the fts3 table. For example, if
+  ** the following SQL is executed:
+  **
+  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
+  **
+  ** then argc is set to 2, and the argv[] array contains pointers
+  ** to the strings "arg1" and "arg2".
+  **
+  ** This method should return either SQLITE_OK (0), or an SQLite error 
+  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
+  ** to point at the newly created tokenizer structure. The generic
+  ** sqlite3_tokenizer.pModule variable should not be initialised by
+  ** this callback. The caller will do so.
+  */
+  int (*xCreate)(
+    int argc,                           /* Size of argv array */
+    const char *const*argv,             /* Tokenizer argument strings */
+    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
+  );
+
+  /*
+  ** Destroy an existing tokenizer. The fts3 module calls this method
+  ** exactly once for each successful call to xCreate().
+  */
+  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+  /*
+  ** Create a tokenizer cursor to tokenize an input buffer. The caller
+  ** is responsible for ensuring that the input buffer remains valid
+  ** until the cursor is closed (using the xClose() method). 
+  */
+  int (*xOpen)(
+    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
+    const char *pInput, int nBytes,      /* Input buffer */
+    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
+  );
+
+  /*
+  ** Destroy an existing tokenizer cursor. The fts3 module calls this 
+  ** method exactly once for each successful call to xOpen().
+  */
+  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+
+  /*
+  ** Retrieve the next token from the tokenizer cursor pCursor. This
+  ** method should either return SQLITE_OK and set the values of the
+  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
+  ** the end of the buffer has been reached, or an SQLite error code.
+  **
+  ** *ppToken should be set to point at a buffer containing the 
+  ** normalized version of the token (i.e. after any case-folding and/or
+  ** stemming has been performed). *pnBytes should be set to the length
+  ** of this buffer in bytes. The input text that generated the token is
+  ** identified by the byte offsets returned in *piStartOffset and
+  ** *piEndOffset.
+  **
+  ** The buffer *ppToken is set to point at is managed by the tokenizer
+  ** implementation. It is only required to be valid until the next call
+  ** to xNext() or xClose(). 
+  */
+  /* TODO(shess) current implementation requires pInput to be
+  ** nul-terminated.  This should either be fixed, or pInput/nBytes
+  ** should be converted to zInput.
+  */
+  int (*xNext)(
+    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
+    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
+    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
+    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
+    int *piPosition      /* OUT: Number of tokens returned before this one */
+  );
+};
+
+struct sqlite3_tokenizer {
+  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+struct sqlite3_tokenizer_cursor {
+  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+#endif /* _FTS3_TOKENIZER_H_ */
+
+/************** End of fts3_tokenizer.h **************************************/
+/************** Continuing where we left off in fts3.c ***********************/
+#ifndef SQLITE_CORE 
+  SQLITE_EXTENSION_INIT1
+#endif
+
+
+/* TODO(shess) MAN, this thing needs some refactoring.  At minimum, it
+** would be nice to order the file better, perhaps something along the
+** lines of:
+**
+**  - utility functions
+**  - table setup functions
+**  - table update functions
+**  - table query functions
+**
+** Put the query functions last because they're likely to reference
+** typedefs or functions from the table update section.
+*/
+
+#if 0
+# define FTSTRACE(A)  printf A; fflush(stdout)
+#else
+# define FTSTRACE(A)
+#endif
+
+/*
+** Default span for NEAR operators.
+*/
+#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
+
+/* It is not safe to call isspace(), tolower(), or isalnum() on
+** hi-bit-set characters.  This is the same solution used in the
+** tokenizer.
+*/
+/* TODO(shess) The snippet-generation code should be using the
+** tokenizer-generated tokens rather than doing its own local
+** tokenization.
+*/
+/* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
+static int safe_isspace(char c){
+  return (c&0x80)==0 ? isspace(c) : 0;
+}
+static int safe_tolower(char c){
+  return (c&0x80)==0 ? tolower(c) : c;
+}
+static int safe_isalnum(char c){
+  return (c&0x80)==0 ? isalnum(c) : 0;
+}
+
+typedef enum DocListType {
+  DL_DOCIDS,              /* docids only */
+  DL_POSITIONS,           /* docids + positions */
+  DL_POSITIONS_OFFSETS    /* docids + positions + offsets */
+} DocListType;
+
+/*
+** By default, only positions and not offsets are stored in the doclists.
+** To change this so that offsets are stored too, compile with
+**
+**          -DDL_DEFAULT=DL_POSITIONS_OFFSETS
+**
+** If DL_DEFAULT is set to DL_DOCIDS, your table can only be inserted
+** into (no deletes or updates).
+*/
+#ifndef DL_DEFAULT
+# define DL_DEFAULT DL_POSITIONS
+#endif
+
+enum {
+  POS_END = 0,        /* end of this position list */
+  POS_COLUMN,         /* followed by new column number */
+  POS_BASE
+};
+
+/* MERGE_COUNT controls how often we merge segments (see comment at
+** top of file).
+*/
+#define MERGE_COUNT 16
+
+/* utility functions */
+
+/* CLEAR() and SCRAMBLE() abstract memset() on a pointer to a single
+** record to prevent errors of the form:
+**
+** my_function(SomeType *b){
+**   memset(b, '\0', sizeof(b));  // sizeof(b)!=sizeof(*b)
+** }
+*/
+/* TODO(shess) Obvious candidates for a header file. */
+#define CLEAR(b) memset(b, '\0', sizeof(*(b)))
+
+#ifndef NDEBUG
+#  define SCRAMBLE(b) memset(b, 0x55, sizeof(*(b)))
+#else
+#  define SCRAMBLE(b)
+#endif
+
+/* We may need up to VARINT_MAX bytes to store an encoded 64-bit integer. */
+#define VARINT_MAX 10
+
+/* Write a 64-bit variable-length integer to memory starting at p[0].
+ * The length of data written will be between 1 and VARINT_MAX bytes.
+ * The number of bytes written is returned. */
+static int fts3PutVarint(char *p, sqlite_int64 v){
+  unsigned char *q = (unsigned char *) p;
+  sqlite_uint64 vu = v;
+  do{
+    *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
+    vu >>= 7;
+  }while( vu!=0 );
+  q[-1] &= 0x7f;  /* turn off high bit in final byte */
+  assert( q - (unsigned char *)p <= VARINT_MAX );
+  return (int) (q - (unsigned char *)p);
+}
+
+/* Read a 64-bit variable-length integer from memory starting at p[0].
+ * Return the number of bytes read, or 0 on error.
+ * The value is stored in *v. */
+static int fts3GetVarint(const char *p, sqlite_int64 *v){
+  const unsigned char *q = (const unsigned char *) p;
+  sqlite_uint64 x = 0, y = 1;
+  while( (*q & 0x80) == 0x80 ){
+    x += y * (*q++ & 0x7f);
+    y <<= 7;
+    if( q - (unsigned char *)p >= VARINT_MAX ){  /* bad data */
+      assert( 0 );
+      return 0;
+    }
+  }
+  x += y * (*q++);
+  *v = (sqlite_int64) x;
+  return (int) (q - (unsigned char *)p);
+}
+
+static int fts3GetVarint32(const char *p, int *pi){
+ sqlite_int64 i;
+ int ret = fts3GetVarint(p, &i);
+ *pi = (int) i;
+ assert( *pi==i );
+ return ret;
+}
+
+/*******************************************************************/
+/* DataBuffer is used to collect data into a buffer in piecemeal
+** fashion.  It implements the usual distinction between amount of
+** data currently stored (nData) and buffer capacity (nCapacity).
+**
+** dataBufferInit - create a buffer with given initial capacity.
+** dataBufferReset - forget buffer's data, retaining capacity.
+** dataBufferDestroy - free buffer's data.
+** dataBufferSwap - swap contents of two buffers.
+** dataBufferExpand - expand capacity without adding data.
+** dataBufferAppend - append data.
+** dataBufferAppend2 - append two pieces of data at once.
+** dataBufferReplace - replace buffer's data.
+*/
+typedef struct DataBuffer {
+  char *pData;          /* Pointer to malloc'ed buffer. */
+  int nCapacity;        /* Size of pData buffer. */
+  int nData;            /* End of data loaded into pData. */
+} DataBuffer;
+
+static void dataBufferInit(DataBuffer *pBuffer, int nCapacity){
+  assert( nCapacity>=0 );
+  pBuffer->nData = 0;
+  pBuffer->nCapacity = nCapacity;
+  pBuffer->pData = nCapacity==0 ? NULL : sqlite3_malloc(nCapacity);
+}
+static void dataBufferReset(DataBuffer *pBuffer){
+  pBuffer->nData = 0;
+}
+static void dataBufferDestroy(DataBuffer *pBuffer){
+  if( pBuffer->pData!=NULL ) sqlite3_free(pBuffer->pData);
+  SCRAMBLE(pBuffer);
+}
+static void dataBufferSwap(DataBuffer *pBuffer1, DataBuffer *pBuffer2){
+  DataBuffer tmp = *pBuffer1;
+  *pBuffer1 = *pBuffer2;
+  *pBuffer2 = tmp;
+}
+static void dataBufferExpand(DataBuffer *pBuffer, int nAddCapacity){
+  assert( nAddCapacity>0 );
+  /* TODO(shess) Consider expanding more aggressively.  Note that the
+  ** underlying malloc implementation may take care of such things for
+  ** us already.
+  */
+  if( pBuffer->nData+nAddCapacity>pBuffer->nCapacity ){
+    pBuffer->nCapacity = pBuffer->nData+nAddCapacity;
+    pBuffer->pData = sqlite3_realloc(pBuffer->pData, pBuffer->nCapacity);
+  }
+}
+static void dataBufferAppend(DataBuffer *pBuffer,
+                             const char *pSource, int nSource){
+  assert( nSource>0 && pSource!=NULL );
+  dataBufferExpand(pBuffer, nSource);
+  memcpy(pBuffer->pData+pBuffer->nData, pSource, nSource);
+  pBuffer->nData += nSource;
+}
+static void dataBufferAppend2(DataBuffer *pBuffer,
+                              const char *pSource1, int nSource1,
+                              const char *pSource2, int nSource2){
+  assert( nSource1>0 && pSource1!=NULL );
+  assert( nSource2>0 && pSource2!=NULL );
+  dataBufferExpand(pBuffer, nSource1+nSource2);
+  memcpy(pBuffer->pData+pBuffer->nData, pSource1, nSource1);
+  memcpy(pBuffer->pData+pBuffer->nData+nSource1, pSource2, nSource2);
+  pBuffer->nData += nSource1+nSource2;
+}
+static void dataBufferReplace(DataBuffer *pBuffer,
+                              const char *pSource, int nSource){
+  dataBufferReset(pBuffer);
+  dataBufferAppend(pBuffer, pSource, nSource);
+}
+
+/* StringBuffer is a null-terminated version of DataBuffer. */
+typedef struct StringBuffer {
+  DataBuffer b;            /* Includes null terminator. */
+} StringBuffer;
+
+static void initStringBuffer(StringBuffer *sb){
+  dataBufferInit(&sb->b, 100);
+  dataBufferReplace(&sb->b, "", 1);
+}
+static int stringBufferLength(StringBuffer *sb){
+  return sb->b.nData-1;
+}
+static char *stringBufferData(StringBuffer *sb){
+  return sb->b.pData;
+}
+static void stringBufferDestroy(StringBuffer *sb){
+  dataBufferDestroy(&sb->b);
+}
+
+static void nappend(StringBuffer *sb, const char *zFrom, int nFrom){
+  assert( sb->b.nData>0 );
+  if( nFrom>0 ){
+    sb->b.nData--;
+    dataBufferAppend2(&sb->b, zFrom, nFrom, "", 1);
+  }
+}
+static void append(StringBuffer *sb, const char *zFrom){
+  nappend(sb, zFrom, strlen(zFrom));
+}
+
+/* Append a list of strings separated by commas. */
+static void appendList(StringBuffer *sb, int nString, char **azString){
+  int i;
+  for(i=0; i<nString; ++i){
+    if( i>0 ) append(sb, ", ");
+    append(sb, azString[i]);
+  }
+}
+
+static int endsInWhiteSpace(StringBuffer *p){
+  return stringBufferLength(p)>0 &&
+    safe_isspace(stringBufferData(p)[stringBufferLength(p)-1]);
+}
+
+/* If the StringBuffer ends in something other than white space, add a
+** single space character to the end.
+*/
+static void appendWhiteSpace(StringBuffer *p){
+  if( stringBufferLength(p)==0 ) return;
+  if( !endsInWhiteSpace(p) ) append(p, " ");
+}
+
+/* Remove white space from the end of the StringBuffer */
+static void trimWhiteSpace(StringBuffer *p){
+  while( endsInWhiteSpace(p) ){
+    p->b.pData[--p->b.nData-1] = '\0';
+  }
+}
+
+/*******************************************************************/
+/* DLReader is used to read document elements from a doclist.  The
+** current docid is cached, so dlrDocid() is fast.  DLReader does not
+** own the doclist buffer.
+**
+** dlrAtEnd - true if there's no more data to read.
+** dlrDocid - docid of current document.
+** dlrDocData - doclist data for current document (including docid).
+** dlrDocDataBytes - length of same.
+** dlrAllDataBytes - length of all remaining data.
+** dlrPosData - position data for current document.
+** dlrPosDataLen - length of pos data for current document (incl POS_END).
+** dlrStep - step to current document.
+** dlrInit - initial for doclist of given type against given data.
+** dlrDestroy - clean up.
+**
+** Expected usage is something like:
+**
+**   DLReader reader;
+**   dlrInit(&reader, pData, nData);
+**   while( !dlrAtEnd(&reader) ){
+**     // calls to dlrDocid() and kin.
+**     dlrStep(&reader);
+**   }
+**   dlrDestroy(&reader);
+*/
+typedef struct DLReader {
+  DocListType iType;
+  const char *pData;
+  int nData;
+
+  sqlite_int64 iDocid;
+  int nElement;
+} DLReader;
+
+static int dlrAtEnd(DLReader *pReader){
+  assert( pReader->nData>=0 );
+  return pReader->nData==0;
+}
+static sqlite_int64 dlrDocid(DLReader *pReader){
+  assert( !dlrAtEnd(pReader) );
+  return pReader->iDocid;
+}
+static const char *dlrDocData(DLReader *pReader){
+  assert( !dlrAtEnd(pReader) );
+  return pReader->pData;
+}
+static int dlrDocDataBytes(DLReader *pReader){
+  assert( !dlrAtEnd(pReader) );
+  return pReader->nElement;
+}
+static int dlrAllDataBytes(DLReader *pReader){
+  assert( !dlrAtEnd(pReader) );
+  return pReader->nData;
+}
+/* TODO(shess) Consider adding a field to track iDocid varint length
+** to make these two functions faster.  This might matter (a tiny bit)
+** for queries.
+*/
+static const char *dlrPosData(DLReader *pReader){
+  sqlite_int64 iDummy;
+  int n = fts3GetVarint(pReader->pData, &iDummy);
+  assert( !dlrAtEnd(pReader) );
+  return pReader->pData+n;
+}
+static int dlrPosDataLen(DLReader *pReader){
+  sqlite_int64 iDummy;
+  int n = fts3GetVarint(pReader->pData, &iDummy);
+  assert( !dlrAtEnd(pReader) );
+  return pReader->nElement-n;
+}
+static void dlrStep(DLReader *pReader){
+  assert( !dlrAtEnd(pReader) );
+
+  /* Skip past current doclist element. */
+  assert( pReader->nElement<=pReader->nData );
+  pReader->pData += pReader->nElement;
+  pReader->nData -= pReader->nElement;
+
+  /* If there is more data, read the next doclist element. */
+  if( pReader->nData!=0 ){
+    sqlite_int64 iDocidDelta;
+    int iDummy, n = fts3GetVarint(pReader->pData, &iDocidDelta);
+    pReader->iDocid += iDocidDelta;
+    if( pReader->iType>=DL_POSITIONS ){
+      assert( n<pReader->nData );
+      while( 1 ){
+        n += fts3GetVarint32(pReader->pData+n, &iDummy);
+        assert( n<=pReader->nData );
+        if( iDummy==POS_END ) break;
+        if( iDummy==POS_COLUMN ){
+          n += fts3GetVarint32(pReader->pData+n, &iDummy);
+          assert( n<pReader->nData );
+        }else if( pReader->iType==DL_POSITIONS_OFFSETS ){
+          n += fts3GetVarint32(pReader->pData+n, &iDummy);
+          n += fts3GetVarint32(pReader->pData+n, &iDummy);
+          assert( n<pReader->nData );
+        }
+      }
+    }
+    pReader->nElement = n;
+    assert( pReader->nElement<=pReader->nData );
+  }
+}
+static void dlrInit(DLReader *pReader, DocListType iType,
+                    const char *pData, int nData){
+  assert( pData!=NULL && nData!=0 );
+  pReader->iType = iType;
+  pReader->pData = pData;
+  pReader->nData = nData;
+  pReader->nElement = 0;
+  pReader->iDocid = 0;
+
+  /* Load the first element's data.  There must be a first element. */
+  dlrStep(pReader);
+}
+static void dlrDestroy(DLReader *pReader){
+  SCRAMBLE(pReader);
+}
+
+#ifndef NDEBUG
+/* Verify that the doclist can be validly decoded.  Also returns the
+** last docid found because it is convenient in other assertions for
+** DLWriter.
+*/
+static void docListValidate(DocListType iType, const char *pData, int nData,
+                            sqlite_int64 *pLastDocid){
+  sqlite_int64 iPrevDocid = 0;
+  assert( nData>0 );
+  assert( pData!=0 );
+  assert( pData+nData>pData );
+  while( nData!=0 ){
+    sqlite_int64 iDocidDelta;
+    int n = fts3GetVarint(pData, &iDocidDelta);
+    iPrevDocid += iDocidDelta;
+    if( iType>DL_DOCIDS ){
+      int iDummy;
+      while( 1 ){
+        n += fts3GetVarint32(pData+n, &iDummy);
+        if( iDummy==POS_END ) break;
+        if( iDummy==POS_COLUMN ){
+          n += fts3GetVarint32(pData+n, &iDummy);
+        }else if( iType>DL_POSITIONS ){
+          n += fts3GetVarint32(pData+n, &iDummy);
+          n += fts3GetVarint32(pData+n, &iDummy);
+        }
+        assert( n<=nData );
+      }
+    }
+    assert( n<=nData );
+    pData += n;
+    nData -= n;
+  }
+  if( pLastDocid ) *pLastDocid = iPrevDocid;
+}
+#define ASSERT_VALID_DOCLIST(i, p, n, o) docListValidate(i, p, n, o)
+#else
+#define ASSERT_VALID_DOCLIST(i, p, n, o) assert( 1 )
+#endif
+
+/*******************************************************************/
+/* DLWriter is used to write doclist data to a DataBuffer.  DLWriter
+** always appends to the buffer and does not own it.
+**
+** dlwInit - initialize to write a given type doclistto a buffer.
+** dlwDestroy - clear the writer's memory.  Does not free buffer.
+** dlwAppend - append raw doclist data to buffer.
+** dlwCopy - copy next doclist from reader to writer.
+** dlwAdd - construct doclist element and append to buffer.
+**    Only apply dlwAdd() to DL_DOCIDS doclists (else use PLWriter).
+*/
+typedef struct DLWriter {
+  DocListType iType;
+  DataBuffer *b;
+  sqlite_int64 iPrevDocid;
+#ifndef NDEBUG
+  int has_iPrevDocid;
+#endif
+} DLWriter;
+
+static void dlwInit(DLWriter *pWriter, DocListType iType, DataBuffer *b){
+  pWriter->b = b;
+  pWriter->iType = iType;
+  pWriter->iPrevDocid = 0;
+#ifndef NDEBUG
+  pWriter->has_iPrevDocid = 0;
+#endif
+}
+static void dlwDestroy(DLWriter *pWriter){
+  SCRAMBLE(pWriter);
+}
+/* iFirstDocid is the first docid in the doclist in pData.  It is
+** needed because pData may point within a larger doclist, in which
+** case the first item would be delta-encoded.
+**
+** iLastDocid is the final docid in the doclist in pData.  It is
+** needed to create the new iPrevDocid for future delta-encoding.  The
+** code could decode the passed doclist to recreate iLastDocid, but
+** the only current user (docListMerge) already has decoded this
+** information.
+*/
+/* TODO(shess) This has become just a helper for docListMerge.
+** Consider a refactor to make this cleaner.
+*/
+static void dlwAppend(DLWriter *pWriter,
+                      const char *pData, int nData,
+                      sqlite_int64 iFirstDocid, sqlite_int64 iLastDocid){
+  sqlite_int64 iDocid = 0;
+  char c[VARINT_MAX];
+  int nFirstOld, nFirstNew;     /* Old and new varint len of first docid. */
+#ifndef NDEBUG
+  sqlite_int64 iLastDocidDelta;
+#endif
+
+  /* Recode the initial docid as delta from iPrevDocid. */
+  nFirstOld = fts3GetVarint(pData, &iDocid);
+  assert( nFirstOld<nData || (nFirstOld==nData && pWriter->iType==DL_DOCIDS) );
+  nFirstNew = fts3PutVarint(c, iFirstDocid-pWriter->iPrevDocid);
+
+  /* Verify that the incoming doclist is valid AND that it ends with
+  ** the expected docid.  This is essential because we'll trust this
+  ** docid in future delta-encoding.
+  */
+  ASSERT_VALID_DOCLIST(pWriter->iType, pData, nData, &iLastDocidDelta);
+  assert( iLastDocid==iFirstDocid-iDocid+iLastDocidDelta );
+
+  /* Append recoded initial docid and everything else.  Rest of docids
+  ** should have been delta-encoded from previous initial docid.
+  */
+  if( nFirstOld<nData ){
+    dataBufferAppend2(pWriter->b, c, nFirstNew,
+                      pData+nFirstOld, nData-nFirstOld);
+  }else{
+    dataBufferAppend(pWriter->b, c, nFirstNew);
+  }
+  pWriter->iPrevDocid = iLastDocid;
+}
+static void dlwCopy(DLWriter *pWriter, DLReader *pReader){
+  dlwAppend(pWriter, dlrDocData(pReader), dlrDocDataBytes(pReader),
+            dlrDocid(pReader), dlrDocid(pReader));
+}
+static void dlwAdd(DLWriter *pWriter, sqlite_int64 iDocid){
+  char c[VARINT_MAX];
+  int n = fts3PutVarint(c, iDocid-pWriter->iPrevDocid);
+
+  /* Docids must ascend. */
+  assert( !pWriter->has_iPrevDocid || iDocid>pWriter->iPrevDocid );
+  assert( pWriter->iType==DL_DOCIDS );
+
+  dataBufferAppend(pWriter->b, c, n);
+  pWriter->iPrevDocid = iDocid;
+#ifndef NDEBUG
+  pWriter->has_iPrevDocid = 1;
+#endif
+}
+
+/*******************************************************************/
+/* PLReader is used to read data from a document's position list.  As
+** the caller steps through the list, data is cached so that varints
+** only need to be decoded once.
+**
+** plrInit, plrDestroy - create/destroy a reader.
+** plrColumn, plrPosition, plrStartOffset, plrEndOffset - accessors
+** plrAtEnd - at end of stream, only call plrDestroy once true.
+** plrStep - step to the next element.
+*/
+typedef struct PLReader {
+  /* These refer to the next position's data.  nData will reach 0 when
+  ** reading the last position, so plrStep() signals EOF by setting
+  ** pData to NULL.
+  */
+  const char *pData;
+  int nData;
+
+  DocListType iType;
+  int iColumn;         /* the last column read */
+  int iPosition;       /* the last position read */
+  int iStartOffset;    /* the last start offset read */
+  int iEndOffset;      /* the last end offset read */
+} PLReader;
+
+static int plrAtEnd(PLReader *pReader){
+  return pReader->pData==NULL;
+}
+static int plrColumn(PLReader *pReader){
+  assert( !plrAtEnd(pReader) );
+  return pReader->iColumn;
+}
+static int plrPosition(PLReader *pReader){
+  assert( !plrAtEnd(pReader) );
+  return pReader->iPosition;
+}
+static int plrStartOffset(PLReader *pReader){
+  assert( !plrAtEnd(pReader) );
+  return pReader->iStartOffset;
+}
+static int plrEndOffset(PLReader *pReader){
+  assert( !plrAtEnd(pReader) );
+  return pReader->iEndOffset;
+}
+static void plrStep(PLReader *pReader){
+  int i, n;
+
+  assert( !plrAtEnd(pReader) );
+
+  if( pReader->nData==0 ){
+    pReader->pData = NULL;
+    return;
+  }
+
+  n = fts3GetVarint32(pReader->pData, &i);
+  if( i==POS_COLUMN ){
+    n += fts3GetVarint32(pReader->pData+n, &pReader->iColumn);
+    pReader->iPosition = 0;
+    pReader->iStartOffset = 0;
+    n += fts3GetVarint32(pReader->pData+n, &i);
+  }
+  /* Should never see adjacent column changes. */
+  assert( i!=POS_COLUMN );
+
+  if( i==POS_END ){
+    pReader->nData = 0;
+    pReader->pData = NULL;
+    return;
+  }
+
+  pReader->iPosition += i-POS_BASE;
+  if( pReader->iType==DL_POSITIONS_OFFSETS ){
+    n += fts3GetVarint32(pReader->pData+n, &i);
+    pReader->iStartOffset += i;
+    n += fts3GetVarint32(pReader->pData+n, &i);
+    pReader->iEndOffset = pReader->iStartOffset+i;
+  }
+  assert( n<=pReader->nData );
+  pReader->pData += n;
+  pReader->nData -= n;
+}
+
+static void plrInit(PLReader *pReader, DLReader *pDLReader){
+  pReader->pData = dlrPosData(pDLReader);
+  pReader->nData = dlrPosDataLen(pDLReader);
+  pReader->iType = pDLReader->iType;
+  pReader->iColumn = 0;
+  pReader->iPosition = 0;
+  pReader->iStartOffset = 0;
+  pReader->iEndOffset = 0;
+  plrStep(pReader);
+}
+static void plrDestroy(PLReader *pReader){
+  SCRAMBLE(pReader);
+}
+
+/*******************************************************************/
+/* PLWriter is used in constructing a document's position list.  As a
+** convenience, if iType is DL_DOCIDS, PLWriter becomes a no-op.
+** PLWriter writes to the associated DLWriter's buffer.
+**
+** plwInit - init for writing a document's poslist.
+** plwDestroy - clear a writer.
+** plwAdd - append position and offset information.
+** plwCopy - copy next position's data from reader to writer.
+** plwTerminate - add any necessary doclist terminator.
+**
+** Calling plwAdd() after plwTerminate() may result in a corrupt
+** doclist.
+*/
+/* TODO(shess) Until we've written the second item, we can cache the
+** first item's information.  Then we'd have three states:
+**
+** - initialized with docid, no positions.
+** - docid and one position.
+** - docid and multiple positions.
+**
+** Only the last state needs to actually write to dlw->b, which would
+** be an improvement in the DLCollector case.
+*/
+typedef struct PLWriter {
+  DLWriter *dlw;
+
+  int iColumn;    /* the last column written */
+  int iPos;       /* the last position written */
+  int iOffset;    /* the last start offset written */
+} PLWriter;
+
+/* TODO(shess) In the case where the parent is reading these values
+** from a PLReader, we could optimize to a copy if that PLReader has
+** the same type as pWriter.
+*/
+static void plwAdd(PLWriter *pWriter, int iColumn, int iPos,
+                   int iStartOffset, int iEndOffset){
+  /* Worst-case space for POS_COLUMN, iColumn, iPosDelta,
+  ** iStartOffsetDelta, and iEndOffsetDelta.
+  */
+  char c[5*VARINT_MAX];
+  int n = 0;
+
+  /* Ban plwAdd() after plwTerminate(). */
+  assert( pWriter->iPos!=-1 );
+
+  if( pWriter->dlw->iType==DL_DOCIDS ) return;
+
+  if( iColumn!=pWriter->iColumn ){
+    n += fts3PutVarint(c+n, POS_COLUMN);
+    n += fts3PutVarint(c+n, iColumn);
+    pWriter->iColumn = iColumn;
+    pWriter->iPos = 0;
+    pWriter->iOffset = 0;
+  }
+  assert( iPos>=pWriter->iPos );
+  n += fts3PutVarint(c+n, POS_BASE+(iPos-pWriter->iPos));
+  pWriter->iPos = iPos;
+  if( pWriter->dlw->iType==DL_POSITIONS_OFFSETS ){
+    assert( iStartOffset>=pWriter->iOffset );
+    n += fts3PutVarint(c+n, iStartOffset-pWriter->iOffset);
+    pWriter->iOffset = iStartOffset;
+    assert( iEndOffset>=iStartOffset );
+    n += fts3PutVarint(c+n, iEndOffset-iStartOffset);
+  }
+  dataBufferAppend(pWriter->dlw->b, c, n);
+}
+static void plwCopy(PLWriter *pWriter, PLReader *pReader){
+  plwAdd(pWriter, plrColumn(pReader), plrPosition(pReader),
+         plrStartOffset(pReader), plrEndOffset(pReader));
+}
+static void plwInit(PLWriter *pWriter, DLWriter *dlw, sqlite_int64 iDocid){
+  char c[VARINT_MAX];
+  int n;
+
+  pWriter->dlw = dlw;
+
+  /* Docids must ascend. */
+  assert( !pWriter->dlw->has_iPrevDocid || iDocid>pWriter->dlw->iPrevDocid );
+  n = fts3PutVarint(c, iDocid-pWriter->dlw->iPrevDocid);
+  dataBufferAppend(pWriter->dlw->b, c, n);
+  pWriter->dlw->iPrevDocid = iDocid;
+#ifndef NDEBUG
+  pWriter->dlw->has_iPrevDocid = 1;
+#endif
+
+  pWriter->iColumn = 0;
+  pWriter->iPos = 0;
+  pWriter->iOffset = 0;
+}
+/* TODO(shess) Should plwDestroy() also terminate the doclist?  But
+** then plwDestroy() would no longer be just a destructor, it would
+** also be doing work, which isn't consistent with the overall idiom.
+** Another option would be for plwAdd() to always append any necessary
+** terminator, so that the output is always correct.  But that would
+** add incremental work to the common case with the only benefit being
+** API elegance.  Punt for now.
+*/
+static void plwTerminate(PLWriter *pWriter){
+  if( pWriter->dlw->iType>DL_DOCIDS ){
+    char c[VARINT_MAX];
+    int n = fts3PutVarint(c, POS_END);
+    dataBufferAppend(pWriter->dlw->b, c, n);
+  }
+#ifndef NDEBUG
+  /* Mark as terminated for assert in plwAdd(). */
+  pWriter->iPos = -1;
+#endif
+}
+static void plwDestroy(PLWriter *pWriter){
+  SCRAMBLE(pWriter);
+}
+
+/*******************************************************************/
+/* DLCollector wraps PLWriter and DLWriter to provide a
+** dynamically-allocated doclist area to use during tokenization.
+**
+** dlcNew - malloc up and initialize a collector.
+** dlcDelete - destroy a collector and all contained items.
+** dlcAddPos - append position and offset information.
+** dlcAddDoclist - add the collected doclist to the given buffer.
+** dlcNext - terminate the current document and open another.
+*/
+typedef struct DLCollector {
+  DataBuffer b;
+  DLWriter dlw;
+  PLWriter plw;
+} DLCollector;
+
+/* TODO(shess) This could also be done by calling plwTerminate() and
+** dataBufferAppend().  I tried that, expecting nominal performance
+** differences, but it seemed to pretty reliably be worth 1% to code
+** it this way.  I suspect it is the incremental malloc overhead (some
+** percentage of the plwTerminate() calls will cause a realloc), so
+** this might be worth revisiting if the DataBuffer implementation
+** changes.
+*/
+static void dlcAddDoclist(DLCollector *pCollector, DataBuffer *b){
+  if( pCollector->dlw.iType>DL_DOCIDS ){
+    char c[VARINT_MAX];
+    int n = fts3PutVarint(c, POS_END);
+    dataBufferAppend2(b, pCollector->b.pData, pCollector->b.nData, c, n);
+  }else{
+    dataBufferAppend(b, pCollector->b.pData, pCollector->b.nData);
+  }
+}
+static void dlcNext(DLCollector *pCollector, sqlite_int64 iDocid){
+  plwTerminate(&pCollector->plw);
+  plwDestroy(&pCollector->plw);
+  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
+}
+static void dlcAddPos(DLCollector *pCollector, int iColumn, int iPos,
+                      int iStartOffset, int iEndOffset){
+  plwAdd(&pCollector->plw, iColumn, iPos, iStartOffset, iEndOffset);
+}
+
+static DLCollector *dlcNew(sqlite_int64 iDocid, DocListType iType){
+  DLCollector *pCollector = sqlite3_malloc(sizeof(DLCollector));
+  dataBufferInit(&pCollector->b, 0);
+  dlwInit(&pCollector->dlw, iType, &pCollector->b);
+  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
+  return pCollector;
+}
+static void dlcDelete(DLCollector *pCollector){
+  plwDestroy(&pCollector->plw);
+  dlwDestroy(&pCollector->dlw);
+  dataBufferDestroy(&pCollector->b);
+  SCRAMBLE(pCollector);
+  sqlite3_free(pCollector);
+}
+
+
+/* Copy the doclist data of iType in pData/nData into *out, trimming
+** unnecessary data as we go.  Only columns matching iColumn are
+** copied, all columns copied if iColumn is -1.  Elements with no
+** matching columns are dropped.  The output is an iOutType doclist.
+*/
+/* NOTE(shess) This code is only valid after all doclists are merged.
+** If this is run before merges, then doclist items which represent
+** deletion will be trimmed, and will thus not effect a deletion
+** during the merge.
+*/
+static void docListTrim(DocListType iType, const char *pData, int nData,
+                        int iColumn, DocListType iOutType, DataBuffer *out){
+  DLReader dlReader;
+  DLWriter dlWriter;
+
+  assert( iOutType<=iType );
+
+  dlrInit(&dlReader, iType, pData, nData);
+  dlwInit(&dlWriter, iOutType, out);
+
+  while( !dlrAtEnd(&dlReader) ){
+    PLReader plReader;
+    PLWriter plWriter;
+    int match = 0;
+
+    plrInit(&plReader, &dlReader);
+
+    while( !plrAtEnd(&plReader) ){
+      if( iColumn==-1 || plrColumn(&plReader)==iColumn ){
+        if( !match ){
+          plwInit(&plWriter, &dlWriter, dlrDocid(&dlReader));
+          match = 1;
+        }
+        plwAdd(&plWriter, plrColumn(&plReader), plrPosition(&plReader),
+               plrStartOffset(&plReader), plrEndOffset(&plReader));
+      }
+      plrStep(&plReader);
+    }
+    if( match ){
+      plwTerminate(&plWriter);
+      plwDestroy(&plWriter);
+    }
+
+    plrDestroy(&plReader);
+    dlrStep(&dlReader);
+  }
+  dlwDestroy(&dlWriter);
+  dlrDestroy(&dlReader);
+}
+
+/* Used by docListMerge() to keep doclists in the ascending order by
+** docid, then ascending order by age (so the newest comes first).
+*/
+typedef struct OrderedDLReader {
+  DLReader *pReader;
+
+  /* TODO(shess) If we assume that docListMerge pReaders is ordered by
+  ** age (which we do), then we could use pReader comparisons to break
+  ** ties.
+  */
+  int idx;
+} OrderedDLReader;
+
+/* Order eof to end, then by docid asc, idx desc. */
+static int orderedDLReaderCmp(OrderedDLReader *r1, OrderedDLReader *r2){
+  if( dlrAtEnd(r1->pReader) ){
+    if( dlrAtEnd(r2->pReader) ) return 0;  /* Both atEnd(). */
+    return 1;                              /* Only r1 atEnd(). */
+  }
+  if( dlrAtEnd(r2->pReader) ) return -1;   /* Only r2 atEnd(). */
+
+  if( dlrDocid(r1->pReader)<dlrDocid(r2->pReader) ) return -1;
+  if( dlrDocid(r1->pReader)>dlrDocid(r2->pReader) ) return 1;
+
+  /* Descending on idx. */
+  return r2->idx-r1->idx;
+}
+
+/* Bubble p[0] to appropriate place in p[1..n-1].  Assumes that
+** p[1..n-1] is already sorted.
+*/
+/* TODO(shess) Is this frequent enough to warrant a binary search?
+** Before implementing that, instrument the code to check.  In most
+** current usage, I expect that p[0] will be less than p[1] a very
+** high proportion of the time.
+*/
+static void orderedDLReaderReorder(OrderedDLReader *p, int n){
+  while( n>1 && orderedDLReaderCmp(p, p+1)>0 ){
+    OrderedDLReader tmp = p[0];
+    p[0] = p[1];
+    p[1] = tmp;
+    n--;
+    p++;
+  }
+}
+
+/* Given an array of doclist readers, merge their doclist elements
+** into out in sorted order (by docid), dropping elements from older
+** readers when there is a duplicate docid.  pReaders is assumed to be
+** ordered by age, oldest first.
+*/
+/* TODO(shess) nReaders must be <= MERGE_COUNT.  This should probably
+** be fixed.
+*/
+static void docListMerge(DataBuffer *out,
+                         DLReader *pReaders, int nReaders){
+  OrderedDLReader readers[MERGE_COUNT];
+  DLWriter writer;
+  int i, n;
+  const char *pStart = 0;
+  int nStart = 0;
+  sqlite_int64 iFirstDocid = 0, iLastDocid = 0;
+
+  assert( nReaders>0 );
+  if( nReaders==1 ){
+    dataBufferAppend(out, dlrDocData(pReaders), dlrAllDataBytes(pReaders));
+    return;
+  }
+
+  assert( nReaders<=MERGE_COUNT );
+  n = 0;
+  for(i=0; i<nReaders; i++){
+    assert( pReaders[i].iType==pReaders[0].iType );
+    readers[i].pReader = pReaders+i;
+    readers[i].idx = i;
+    n += dlrAllDataBytes(&pReaders[i]);
+  }
+  /* Conservatively size output to sum of inputs.  Output should end
+  ** up strictly smaller than input.
+  */
+  dataBufferExpand(out, n);
+
+  /* Get the readers into sorted order. */
+  while( i-->0 ){
+    orderedDLReaderReorder(readers+i, nReaders-i);
+  }
+
+  dlwInit(&writer, pReaders[0].iType, out);
+  while( !dlrAtEnd(readers[0].pReader) ){
+    sqlite_int64 iDocid = dlrDocid(readers[0].pReader);
+
+    /* If this is a continuation of the current buffer to copy, extend
+    ** that buffer.  memcpy() seems to be more efficient if it has a
+    ** lots of data to copy.
+    */
+    if( dlrDocData(readers[0].pReader)==pStart+nStart ){
+      nStart += dlrDocDataBytes(readers[0].pReader);
+    }else{
+      if( pStart!=0 ){
+        dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
+      }
+      pStart = dlrDocData(readers[0].pReader);
+      nStart = dlrDocDataBytes(readers[0].pReader);
+      iFirstDocid = iDocid;
+    }
+    iLastDocid = iDocid;
+    dlrStep(readers[0].pReader);
+
+    /* Drop all of the older elements with the same docid. */
+    for(i=1; i<nReaders &&
+             !dlrAtEnd(readers[i].pReader) &&
+             dlrDocid(readers[i].pReader)==iDocid; i++){
+      dlrStep(readers[i].pReader);
+    }
+
+    /* Get the readers back into order. */
+    while( i-->0 ){
+      orderedDLReaderReorder(readers+i, nReaders-i);
+    }
+  }
+
+  /* Copy over any remaining elements. */
+  if( nStart>0 ) dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
+  dlwDestroy(&writer);
+}
+
+/* Helper function for posListUnion().  Compares the current position
+** between left and right, returning as standard C idiom of <0 if
+** left<right, >0 if left>right, and 0 if left==right.  "End" always
+** compares greater.
+*/
+static int posListCmp(PLReader *pLeft, PLReader *pRight){
+  assert( pLeft->iType==pRight->iType );
+  if( pLeft->iType==DL_DOCIDS ) return 0;
+
+  if( plrAtEnd(pLeft) ) return plrAtEnd(pRight) ? 0 : 1;
+  if( plrAtEnd(pRight) ) return -1;
+
+  if( plrColumn(pLeft)<plrColumn(pRight) ) return -1;
+  if( plrColumn(pLeft)>plrColumn(pRight) ) return 1;
+
+  if( plrPosition(pLeft)<plrPosition(pRight) ) return -1;
+  if( plrPosition(pLeft)>plrPosition(pRight) ) return 1;
+  if( pLeft->iType==DL_POSITIONS ) return 0;
+
+  if( plrStartOffset(pLeft)<plrStartOffset(pRight) ) return -1;
+  if( plrStartOffset(pLeft)>plrStartOffset(pRight) ) return 1;
+
+  if( plrEndOffset(pLeft)<plrEndOffset(pRight) ) return -1;
+  if( plrEndOffset(pLeft)>plrEndOffset(pRight) ) return 1;
+
+  return 0;
+}
+
+/* Write the union of position lists in pLeft and pRight to pOut.
+** "Union" in this case meaning "All unique position tuples".  Should
+** work with any doclist type, though both inputs and the output
+** should be the same type.
+*/
+static void posListUnion(DLReader *pLeft, DLReader *pRight, DLWriter *pOut){
+  PLReader left, right;
+  PLWriter writer;
+
+  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
+  assert( pLeft->iType==pRight->iType );
+  assert( pLeft->iType==pOut->iType );
+
+  plrInit(&left, pLeft);
+  plrInit(&right, pRight);
+  plwInit(&writer, pOut, dlrDocid(pLeft));
+
+  while( !plrAtEnd(&left) || !plrAtEnd(&right) ){
+    int c = posListCmp(&left, &right);
+    if( c<0 ){
+      plwCopy(&writer, &left);
+      plrStep(&left);
+    }else if( c>0 ){
+      plwCopy(&writer, &right);
+      plrStep(&right);
+    }else{
+      plwCopy(&writer, &left);
+      plrStep(&left);
+      plrStep(&right);
+    }
+  }
+
+  plwTerminate(&writer);
+  plwDestroy(&writer);
+  plrDestroy(&left);
+  plrDestroy(&right);
+}
+
+/* Write the union of doclists in pLeft and pRight to pOut.  For
+** docids in common between the inputs, the union of the position
+** lists is written.  Inputs and outputs are always type DL_DEFAULT.
+*/
+static void docListUnion(
+  const char *pLeft, int nLeft,
+  const char *pRight, int nRight,
+  DataBuffer *pOut      /* Write the combined doclist here */
+){
+  DLReader left, right;
+  DLWriter writer;
+
+  if( nLeft==0 ){
+    if( nRight!=0) dataBufferAppend(pOut, pRight, nRight);
+    return;
+  }
+  if( nRight==0 ){
+    dataBufferAppend(pOut, pLeft, nLeft);
+    return;
+  }
+
+  dlrInit(&left, DL_DEFAULT, pLeft, nLeft);
+  dlrInit(&right, DL_DEFAULT, pRight, nRight);
+  dlwInit(&writer, DL_DEFAULT, pOut);
+
+  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
+    if( dlrAtEnd(&right) ){
+      dlwCopy(&writer, &left);
+      dlrStep(&left);
+    }else if( dlrAtEnd(&left) ){
+      dlwCopy(&writer, &right);
+      dlrStep(&right);
+    }else if( dlrDocid(&left)<dlrDocid(&right) ){
+      dlwCopy(&writer, &left);
+      dlrStep(&left);
+    }else if( dlrDocid(&left)>dlrDocid(&right) ){
+      dlwCopy(&writer, &right);
+      dlrStep(&right);
+    }else{
+      posListUnion(&left, &right, &writer);
+      dlrStep(&left);
+      dlrStep(&right);
+    }
+  }
+
+  dlrDestroy(&left);
+  dlrDestroy(&right);
+  dlwDestroy(&writer);
+}
+
+/* 
+** This function is used as part of the implementation of phrase and
+** NEAR matching.
+**
+** pLeft and pRight are DLReaders positioned to the same docid in
+** lists of type DL_POSITION. This function writes an entry to the
+** DLWriter pOut for each position in pRight that is less than
+** (nNear+1) greater (but not equal to or smaller) than a position 
+** in pLeft. For example, if nNear is 0, and the positions contained
+** by pLeft and pRight are:
+**
+**    pLeft:  5 10 15 20
+**    pRight: 6  9 17 21
+**
+** then the docid is added to pOut. If pOut is of type DL_POSITIONS,
+** then a positionids "6" and "21" are also added to pOut.
+**
+** If boolean argument isSaveLeft is true, then positionids are copied
+** from pLeft instead of pRight. In the example above, the positions "5"
+** and "20" would be added instead of "6" and "21".
+*/
+static void posListPhraseMerge(
+  DLReader *pLeft, 
+  DLReader *pRight,
+  int nNear,
+  int isSaveLeft,
+  DLWriter *pOut
+){
+  PLReader left, right;
+  PLWriter writer;
+  int match = 0;
+
+  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
+  assert( pOut->iType!=DL_POSITIONS_OFFSETS );
+
+  plrInit(&left, pLeft);
+  plrInit(&right, pRight);
+
+  while( !plrAtEnd(&left) && !plrAtEnd(&right) ){
+    if( plrColumn(&left)<plrColumn(&right) ){
+      plrStep(&left);
+    }else if( plrColumn(&left)>plrColumn(&right) ){
+      plrStep(&right);
+    }else if( plrPosition(&left)>=plrPosition(&right) ){
+      plrStep(&right);
+    }else{
+      if( (plrPosition(&right)-plrPosition(&left))<=(nNear+1) ){
+        if( !match ){
+          plwInit(&writer, pOut, dlrDocid(pLeft));
+          match = 1;
+        }
+        if( !isSaveLeft ){
+          plwAdd(&writer, plrColumn(&right), plrPosition(&right), 0, 0);
+        }else{
+          plwAdd(&writer, plrColumn(&left), plrPosition(&left), 0, 0);
+        }
+        plrStep(&right);
+      }else{
+        plrStep(&left);
+      }
+    }
+  }
+
+  if( match ){
+    plwTerminate(&writer);
+    plwDestroy(&writer);
+  }
+
+  plrDestroy(&left);
+  plrDestroy(&right);
+}
+
+/*
+** Compare the values pointed to by the PLReaders passed as arguments. 
+** Return -1 if the value pointed to by pLeft is considered less than
+** the value pointed to by pRight, +1 if it is considered greater
+** than it, or 0 if it is equal. i.e.
+**
+**     (*pLeft - *pRight)
+**
+** A PLReader that is in the EOF condition is considered greater than
+** any other. If neither argument is in EOF state, the return value of
+** plrColumn() is used. If the plrColumn() values are equal, the
+** comparison is on the basis of plrPosition().
+*/
+static int plrCompare(PLReader *pLeft, PLReader *pRight){
+  assert(!plrAtEnd(pLeft) || !plrAtEnd(pRight));
+
+  if( plrAtEnd(pRight) || plrAtEnd(pLeft) ){
+    return (plrAtEnd(pRight) ? -1 : 1);
+  }
+  if( plrColumn(pLeft)!=plrColumn(pRight) ){
+    return ((plrColumn(pLeft)<plrColumn(pRight)) ? -1 : 1);
+  }
+  if( plrPosition(pLeft)!=plrPosition(pRight) ){
+    return ((plrPosition(pLeft)<plrPosition(pRight)) ? -1 : 1);
+  }
+  return 0;
+}
+
+/* We have two doclists with positions:  pLeft and pRight. Depending
+** on the value of the nNear parameter, perform either a phrase
+** intersection (if nNear==0) or a NEAR intersection (if nNear>0)
+** and write the results into pOut.
+**
+** A phrase intersection means that two documents only match
+** if pLeft.iPos+1==pRight.iPos.
+**
+** A NEAR intersection means that two documents only match if 
+** (abs(pLeft.iPos-pRight.iPos)<nNear).
+**
+** If a NEAR intersection is requested, then the nPhrase argument should
+** be passed the number of tokens in the two operands to the NEAR operator
+** combined. For example:
+**
+**       Query syntax               nPhrase
+**      ------------------------------------
+**       "A B C" NEAR "D E"         5
+**       A NEAR B                   2
+**
+** iType controls the type of data written to pOut.  If iType is
+** DL_POSITIONS, the positions are those from pRight.
+*/
+static void docListPhraseMerge(
+  const char *pLeft, int nLeft,
+  const char *pRight, int nRight,
+  int nNear,            /* 0 for a phrase merge, non-zero for a NEAR merge */
+  int nPhrase,          /* Number of tokens in left+right operands to NEAR */
+  DocListType iType,    /* Type of doclist to write to pOut */
+  DataBuffer *pOut      /* Write the combined doclist here */
+){
+  DLReader left, right;
+  DLWriter writer;
+
+  if( nLeft==0 || nRight==0 ) return;
+
+  assert( iType!=DL_POSITIONS_OFFSETS );
+
+  dlrInit(&left, DL_POSITIONS, pLeft, nLeft);
+  dlrInit(&right, DL_POSITIONS, pRight, nRight);
+  dlwInit(&writer, iType, pOut);
+
+  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
+    if( dlrDocid(&left)<dlrDocid(&right) ){
+      dlrStep(&left);
+    }else if( dlrDocid(&right)<dlrDocid(&left) ){
+      dlrStep(&right);
+    }else{
+      if( nNear==0 ){
+        posListPhraseMerge(&left, &right, 0, 0, &writer);
+      }else{
+        /* This case occurs when two terms (simple terms or phrases) are
+         * connected by a NEAR operator, span (nNear+1). i.e.
+         *
+         *     '"terrible company" NEAR widget'
+         */
+        DataBuffer one = {0, 0, 0};
+        DataBuffer two = {0, 0, 0};
+
+        DLWriter dlwriter2;
+        DLReader dr1 = {0, 0, 0, 0, 0}; 
+        DLReader dr2 = {0, 0, 0, 0, 0};
+
+        dlwInit(&dlwriter2, iType, &one);
+        posListPhraseMerge(&right, &left, nNear-3+nPhrase, 1, &dlwriter2);
+        dlwInit(&dlwriter2, iType, &two);
+        posListPhraseMerge(&left, &right, nNear-1, 0, &dlwriter2);
+
+        if( one.nData) dlrInit(&dr1, iType, one.pData, one.nData);
+        if( two.nData) dlrInit(&dr2, iType, two.pData, two.nData);
+
+        if( !dlrAtEnd(&dr1) || !dlrAtEnd(&dr2) ){
+          PLReader pr1 = {0};
+          PLReader pr2 = {0};
+
+          PLWriter plwriter;
+          plwInit(&plwriter, &writer, dlrDocid(dlrAtEnd(&dr1)?&dr2:&dr1));
+
+          if( one.nData ) plrInit(&pr1, &dr1);
+          if( two.nData ) plrInit(&pr2, &dr2);
+          while( !plrAtEnd(&pr1) || !plrAtEnd(&pr2) ){
+            int iCompare = plrCompare(&pr1, &pr2);
+            switch( iCompare ){
+              case -1:
+                plwCopy(&plwriter, &pr1);
+                plrStep(&pr1);
+                break;
+              case 1:
+                plwCopy(&plwriter, &pr2);
+                plrStep(&pr2);
+                break;
+              case 0:
+                plwCopy(&plwriter, &pr1);
+                plrStep(&pr1);
+                plrStep(&pr2);
+                break;
+            }
+          }
+          plwTerminate(&plwriter);
+        }
+        dataBufferDestroy(&one);
+        dataBufferDestroy(&two);
+      }
+      dlrStep(&left);
+      dlrStep(&right);
+    }
+  }
+
+  dlrDestroy(&left);
+  dlrDestroy(&right);
+  dlwDestroy(&writer);
+}
+
+/* We have two DL_DOCIDS doclists:  pLeft and pRight.
+** Write the intersection of these two doclists into pOut as a
+** DL_DOCIDS doclist.
+*/
+static void docListAndMerge(
+  const char *pLeft, int nLeft,
+  const char *pRight, int nRight,
+  DataBuffer *pOut      /* Write the combined doclist here */
+){
+  DLReader left, right;
+  DLWriter writer;
+
+  if( nLeft==0 || nRight==0 ) return;
+
+  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
+  dlrInit(&right, DL_DOCIDS, pRight, nRight);
+  dlwInit(&writer, DL_DOCIDS, pOut);
+
+  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
+    if( dlrDocid(&left)<dlrDocid(&right) ){
+      dlrStep(&left);
+    }else if( dlrDocid(&right)<dlrDocid(&left) ){
+      dlrStep(&right);
+    }else{
+      dlwAdd(&writer, dlrDocid(&left));
+      dlrStep(&left);
+      dlrStep(&right);
+    }
+  }
+
+  dlrDestroy(&left);
+  dlrDestroy(&right);
+  dlwDestroy(&writer);
+}
+
+/* We have two DL_DOCIDS doclists:  pLeft and pRight.
+** Write the union of these two doclists into pOut as a
+** DL_DOCIDS doclist.
+*/
+static void docListOrMerge(
+  const char *pLeft, int nLeft,
+  const char *pRight, int nRight,
+  DataBuffer *pOut      /* Write the combined doclist here */
+){
+  DLReader left, right;
+  DLWriter writer;
+
+  if( nLeft==0 ){
+    if( nRight!=0 ) dataBufferAppend(pOut, pRight, nRight);
+    return;
+  }
+  if( nRight==0 ){
+    dataBufferAppend(pOut, pLeft, nLeft);
+    return;
+  }
+
+  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
+  dlrInit(&right, DL_DOCIDS, pRight, nRight);
+  dlwInit(&writer, DL_DOCIDS, pOut);
+
+  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
+    if( dlrAtEnd(&right) ){
+      dlwAdd(&writer, dlrDocid(&left));
+      dlrStep(&left);
+    }else if( dlrAtEnd(&left) ){
+      dlwAdd(&writer, dlrDocid(&right));
+      dlrStep(&right);
+    }else if( dlrDocid(&left)<dlrDocid(&right) ){
+      dlwAdd(&writer, dlrDocid(&left));
+      dlrStep(&left);
+    }else if( dlrDocid(&right)<dlrDocid(&left) ){
+      dlwAdd(&writer, dlrDocid(&right));
+      dlrStep(&right);
+    }else{
+      dlwAdd(&writer, dlrDocid(&left));
+      dlrStep(&left);
+      dlrStep(&right);
+    }
+  }
+
+  dlrDestroy(&left);
+  dlrDestroy(&right);
+  dlwDestroy(&writer);
+}
+
+/* We have two DL_DOCIDS doclists:  pLeft and pRight.
+** Write into pOut as DL_DOCIDS doclist containing all documents that
+** occur in pLeft but not in pRight.
+*/
+static void docListExceptMerge(
+  const char *pLeft, int nLeft,
+  const char *pRight, int nRight,
+  DataBuffer *pOut      /* Write the combined doclist here */
+){
+  DLReader left, right;
+  DLWriter writer;
+
+  if( nLeft==0 ) return;
+  if( nRight==0 ){
+    dataBufferAppend(pOut, pLeft, nLeft);
+    return;
+  }
+
+  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
+  dlrInit(&right, DL_DOCIDS, pRight, nRight);
+  dlwInit(&writer, DL_DOCIDS, pOut);
+
+  while( !dlrAtEnd(&left) ){
+    while( !dlrAtEnd(&right) && dlrDocid(&right)<dlrDocid(&left) ){
+      dlrStep(&right);
+    }
+    if( dlrAtEnd(&right) || dlrDocid(&left)<dlrDocid(&right) ){
+      dlwAdd(&writer, dlrDocid(&left));
+    }
+    dlrStep(&left);
+  }
+
+  dlrDestroy(&left);
+  dlrDestroy(&right);
+  dlwDestroy(&writer);
+}
+
+static char *string_dup_n(const char *s, int n){
+  char *str = sqlite3_malloc(n + 1);
+  memcpy(str, s, n);
+  str[n] = '\0';
+  return str;
+}
+
+/* Duplicate a string; the caller must free() the returned string.
+ * (We don't use strdup() since it is not part of the standard C library and
+ * may not be available everywhere.) */
+static char *string_dup(const char *s){
+  return string_dup_n(s, strlen(s));
+}
+
+/* Format a string, replacing each occurrence of the % character with
+ * zDb.zName.  This may be more convenient than sqlite_mprintf()
+ * when one string is used repeatedly in a format string.
+ * The caller must free() the returned string. */
+static char *string_format(const char *zFormat,
+                           const char *zDb, const char *zName){
+  const char *p;
+  size_t len = 0;
+  size_t nDb = strlen(zDb);
+  size_t nName = strlen(zName);
+  size_t nFullTableName = nDb+1+nName;
+  char *result;
+  char *r;
+
+  /* first compute length needed */
+  for(p = zFormat ; *p ; ++p){
+    len += (*p=='%' ? nFullTableName : 1);
+  }
+  len += 1;  /* for null terminator */
+
+  r = result = sqlite3_malloc(len);
+  for(p = zFormat; *p; ++p){
+    if( *p=='%' ){
+      memcpy(r, zDb, nDb);
+      r += nDb;
+      *r++ = '.';
+      memcpy(r, zName, nName);
+      r += nName;
+    } else {
+      *r++ = *p;
+    }
+  }
+  *r++ = '\0';
+  assert( r == result + len );
+  return result;
+}
+
+static int sql_exec(sqlite3 *db, const char *zDb, const char *zName,
+                    const char *zFormat){
+  char *zCommand = string_format(zFormat, zDb, zName);
+  int rc;
+  FTSTRACE(("FTS3 sql: %s\n", zCommand));
+  rc = sqlite3_exec(db, zCommand, NULL, 0, NULL);
+  sqlite3_free(zCommand);
+  return rc;
+}
+
+static int sql_prepare(sqlite3 *db, const char *zDb, const char *zName,
+                       sqlite3_stmt **ppStmt, const char *zFormat){
+  char *zCommand = string_format(zFormat, zDb, zName);
+  int rc;
+  FTSTRACE(("FTS3 prepare: %s\n", zCommand));
+  rc = sqlite3_prepare_v2(db, zCommand, -1, ppStmt, NULL);
+  sqlite3_free(zCommand);
+  return rc;
+}
+
+/* end utility functions */
+
+/* Forward reference */
+typedef struct fulltext_vtab fulltext_vtab;
+
+/* A single term in a query is represented by an instances of
+** the following structure. Each word which may match against
+** document content is a term. Operators, like NEAR or OR, are
+** not terms. Query terms are organized as a flat list stored
+** in the Query.pTerms array.
+**
+** If the QueryTerm.nPhrase variable is non-zero, then the QueryTerm
+** is the first in a contiguous string of terms that are either part
+** of the same phrase, or connected by the NEAR operator.
+**
+** If the QueryTerm.nNear variable is non-zero, then the token is followed 
+** by a NEAR operator with span set to (nNear-1). For example, the 
+** following query:
+**
+** The QueryTerm.iPhrase variable stores the index of the token within
+** its phrase, indexed starting at 1, or 1 if the token is not part 
+** of any phrase.
+**
+** For example, the data structure used to represent the following query:
+**
+**     ... MATCH 'sqlite NEAR/5 google NEAR/2 "search engine"'
+**
+** is:
+**
+**     {nPhrase=4, iPhrase=1, nNear=6, pTerm="sqlite"},
+**     {nPhrase=0, iPhrase=1, nNear=3, pTerm="google"},
+**     {nPhrase=0, iPhrase=1, nNear=0, pTerm="search"},
+**     {nPhrase=0, iPhrase=2, nNear=0, pTerm="engine"},
+**
+** compiling the FTS3 syntax to Query structures is done by the parseQuery()
+** function.
+*/
+typedef struct QueryTerm {
+  short int nPhrase; /* How many following terms are part of the same phrase */
+  short int iPhrase; /* This is the i-th term of a phrase. */
+  short int iColumn; /* Column of the index that must match this term */
+  signed char nNear; /* term followed by a NEAR operator with span=(nNear-1) */
+  signed char isOr;  /* this term is preceded by "OR" */
+  signed char isNot; /* this term is preceded by "-" */
+  signed char isPrefix; /* this term is followed by "*" */
+  char *pTerm;       /* text of the term.  '\000' terminated.  malloced */
+  int nTerm;         /* Number of bytes in pTerm[] */
+} QueryTerm;
+
+
+/* A query string is parsed into a Query structure.
+ *
+ * We could, in theory, allow query strings to be complicated
+ * nested expressions with precedence determined by parentheses.
+ * But none of the major search engines do this.  (Perhaps the
+ * feeling is that an parenthesized expression is two complex of
+ * an idea for the average user to grasp.)  Taking our lead from
+ * the major search engines, we will allow queries to be a list
+ * of terms (with an implied AND operator) or phrases in double-quotes,
+ * with a single optional "-" before each non-phrase term to designate
+ * negation and an optional OR connector.
+ *
+ * OR binds more tightly than the implied AND, which is what the
+ * major search engines seem to do.  So, for example:
+ * 
+ *    [one two OR three]     ==>    one AND (two OR three)
+ *    [one OR two three]     ==>    (one OR two) AND three
+ *
+ * A "-" before a term matches all entries that lack that term.
+ * The "-" must occur immediately before the term with in intervening
+ * space.  This is how the search engines do it.
+ *
+ * A NOT term cannot be the right-hand operand of an OR.  If this
+ * occurs in the query string, the NOT is ignored:
+ *
+ *    [one OR -two]          ==>    one OR two
+ *
+ */
+typedef struct Query {
+  fulltext_vtab *pFts;  /* The full text index */
+  int nTerms;           /* Number of terms in the query */
+  QueryTerm *pTerms;    /* Array of terms.  Space obtained from malloc() */
+  int nextIsOr;         /* Set the isOr flag on the next inserted term */
+  int nextIsNear;       /* Set the isOr flag on the next inserted term */
+  int nextColumn;       /* Next word parsed must be in this column */
+  int dfltColumn;       /* The default column */
+} Query;
+
+
+/*
+** An instance of the following structure keeps track of generated
+** matching-word offset information and snippets.
+*/
+typedef struct Snippet {
+  int nMatch;     /* Total number of matches */
+  int nAlloc;     /* Space allocated for aMatch[] */
+  struct snippetMatch { /* One entry for each matching term */
+    char snStatus;       /* Status flag for use while constructing snippets */
+    short int iCol;      /* The column that contains the match */
+    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
+    int iToken;          /* The index of the matching document token */
+    short int nByte;     /* Number of bytes in the term */
+    int iStart;          /* The offset to the first character of the term */
+  } *aMatch;      /* Points to space obtained from malloc */
+  char *zOffset;  /* Text rendering of aMatch[] */
+  int nOffset;    /* strlen(zOffset) */
+  char *zSnippet; /* Snippet text */
+  int nSnippet;   /* strlen(zSnippet) */
+} Snippet;
+
+
+typedef enum QueryType {
+  QUERY_GENERIC,   /* table scan */
+  QUERY_DOCID,     /* lookup by docid */
+  QUERY_FULLTEXT   /* QUERY_FULLTEXT + [i] is a full-text search for column i*/
+} QueryType;
+
+typedef enum fulltext_statement {
+  CONTENT_INSERT_STMT,
+  CONTENT_SELECT_STMT,
+  CONTENT_UPDATE_STMT,
+  CONTENT_DELETE_STMT,
+
+  BLOCK_INSERT_STMT,
+  BLOCK_SELECT_STMT,
+  BLOCK_DELETE_STMT,
+
+  SEGDIR_MAX_INDEX_STMT,
+  SEGDIR_SET_STMT,
+  SEGDIR_SELECT_STMT,
+  SEGDIR_SPAN_STMT,
+  SEGDIR_DELETE_STMT,
+  SEGDIR_SELECT_ALL_STMT,
+
+  MAX_STMT                     /* Always at end! */
+} fulltext_statement;
+
+/* These must exactly match the enum above. */
+/* TODO(shess): Is there some risk that a statement will be used in two
+** cursors at once, e.g.  if a query joins a virtual table to itself?
+** If so perhaps we should move some of these to the cursor object.
+*/
+static const char *const fulltext_zStatement[MAX_STMT] = {
+  /* CONTENT_INSERT */ NULL,  /* generated in contentInsertStatement() */
+  /* CONTENT_SELECT */ NULL,  /* generated in contentSelectStatement() */
+  /* CONTENT_UPDATE */ NULL,  /* generated in contentUpdateStatement() */
+  /* CONTENT_DELETE */ "delete from %_content where docid = ?",
+
+  /* BLOCK_INSERT */
+  "insert into %_segments (blockid, block) values (null, ?)",
+  /* BLOCK_SELECT */ "select block from %_segments where blockid = ?",
+  /* BLOCK_DELETE */ "delete from %_segments where blockid between ? and ?",
+
+  /* SEGDIR_MAX_INDEX */ "select max(idx) from %_segdir where level = ?",
+  /* SEGDIR_SET */ "insert into %_segdir values (?, ?, ?, ?, ?, ?)",
+  /* SEGDIR_SELECT */
+  "select start_block, leaves_end_block, root from %_segdir "
+  " where level = ? order by idx",
+  /* SEGDIR_SPAN */
+  "select min(start_block), max(end_block) from %_segdir "
+  " where level = ? and start_block <> 0",
+  /* SEGDIR_DELETE */ "delete from %_segdir where level = ?",
+  /* SEGDIR_SELECT_ALL */
+  "select root, leaves_end_block from %_segdir order by level desc, idx",
+};
+
+/*
+** A connection to a fulltext index is an instance of the following
+** structure.  The xCreate and xConnect methods create an instance
+** of this structure and xDestroy and xDisconnect free that instance.
+** All other methods receive a pointer to the structure as one of their
+** arguments.
+*/
+struct fulltext_vtab {
+  sqlite3_vtab base;               /* Base class used by SQLite core */
+  sqlite3 *db;                     /* The database connection */
+  const char *zDb;                 /* logical database name */
+  const char *zName;               /* virtual table name */
+  int nColumn;                     /* number of columns in virtual table */
+  char **azColumn;                 /* column names.  malloced */
+  char **azContentColumn;          /* column names in content table; malloced */
+  sqlite3_tokenizer *pTokenizer;   /* tokenizer for inserts and queries */
+
+  /* Precompiled statements which we keep as long as the table is
+  ** open.
+  */
+  sqlite3_stmt *pFulltextStatements[MAX_STMT];
+
+  /* Precompiled statements used for segment merges.  We run a
+  ** separate select across the leaf level of each tree being merged.
+  */
+  sqlite3_stmt *pLeafSelectStmts[MERGE_COUNT];
+  /* The statement used to prepare pLeafSelectStmts. */
+#define LEAF_SELECT \
+  "select block from %_segments where blockid between ? and ? order by blockid"
+
+  /* These buffer pending index updates during transactions.
+  ** nPendingData estimates the memory size of the pending data.  It
+  ** doesn't include the hash-bucket overhead, nor any malloc
+  ** overhead.  When nPendingData exceeds kPendingThreshold, the
+  ** buffer is flushed even before the transaction closes.
+  ** pendingTerms stores the data, and is only valid when nPendingData
+  ** is >=0 (nPendingData<0 means pendingTerms has not been
+  ** initialized).  iPrevDocid is the last docid written, used to make
+  ** certain we're inserting in sorted order.
+  */
+  int nPendingData;
+#define kPendingThreshold (1*1024*1024)
+  sqlite_int64 iPrevDocid;
+  fts3Hash pendingTerms;
+};
+
+/*
+** When the core wants to do a query, it create a cursor using a
+** call to xOpen.  This structure is an instance of a cursor.  It
+** is destroyed by xClose.
+*/
+typedef struct fulltext_cursor {
+  sqlite3_vtab_cursor base;        /* Base class used by SQLite core */
+  QueryType iCursorType;           /* Copy of sqlite3_index_info.idxNum */
+  sqlite3_stmt *pStmt;             /* Prepared statement in use by the cursor */
+  int eof;                         /* True if at End Of Results */
+  Query q;                         /* Parsed query string */
+  Snippet snippet;                 /* Cached snippet for the current row */
+  int iColumn;                     /* Column being searched */
+  DataBuffer result;               /* Doclist results from fulltextQuery */
+  DLReader reader;                 /* Result reader if result not empty */
+} fulltext_cursor;
+
+static struct fulltext_vtab *cursor_vtab(fulltext_cursor *c){
+  return (fulltext_vtab *) c->base.pVtab;
+}
+
+static const sqlite3_module fts3Module;   /* forward declaration */
+
+/* Return a dynamically generated statement of the form
+ *   insert into %_content (docid, ...) values (?, ...)
+ */
+static const char *contentInsertStatement(fulltext_vtab *v){
+  StringBuffer sb;
+  int i;
+
+  initStringBuffer(&sb);
+  append(&sb, "insert into %_content (docid, ");
+  appendList(&sb, v->nColumn, v->azContentColumn);
+  append(&sb, ") values (?");
+  for(i=0; i<v->nColumn; ++i)
+    append(&sb, ", ?");
+  append(&sb, ")");
+  return stringBufferData(&sb);
+}
+
+/* Return a dynamically generated statement of the form
+ *   select <content columns> from %_content where docid = ?
+ */
+static const char *contentSelectStatement(fulltext_vtab *v){
+  StringBuffer sb;
+  initStringBuffer(&sb);
+  append(&sb, "SELECT ");
+  appendList(&sb, v->nColumn, v->azContentColumn);
+  append(&sb, " FROM %_content WHERE docid = ?");
+  return stringBufferData(&sb);
+}
+
+/* Return a dynamically generated statement of the form
+ *   update %_content set [col_0] = ?, [col_1] = ?, ...
+ *                    where docid = ?
+ */
+static const char *contentUpdateStatement(fulltext_vtab *v){
+  StringBuffer sb;
+  int i;
+
+  initStringBuffer(&sb);
+  append(&sb, "update %_content set ");
+  for(i=0; i<v->nColumn; ++i) {
+    if( i>0 ){
+      append(&sb, ", ");
+    }
+    append(&sb, v->azContentColumn[i]);
+    append(&sb, " = ?");
+  }
+  append(&sb, " where docid = ?");
+  return stringBufferData(&sb);
+}
+
+/* Puts a freshly-prepared statement determined by iStmt in *ppStmt.
+** If the indicated statement has never been prepared, it is prepared
+** and cached, otherwise the cached version is reset.
+*/
+static int sql_get_statement(fulltext_vtab *v, fulltext_statement iStmt,
+                             sqlite3_stmt **ppStmt){
+  assert( iStmt<MAX_STMT );
+  if( v->pFulltextStatements[iStmt]==NULL ){
+    const char *zStmt;
+    int rc;
+    switch( iStmt ){
+      case CONTENT_INSERT_STMT:
+        zStmt = contentInsertStatement(v); break;
+      case CONTENT_SELECT_STMT:
+        zStmt = contentSelectStatement(v); break;
+      case CONTENT_UPDATE_STMT:
+        zStmt = contentUpdateStatement(v); break;
+      default:
+        zStmt = fulltext_zStatement[iStmt];
+    }
+    rc = sql_prepare(v->db, v->zDb, v->zName, &v->pFulltextStatements[iStmt],
+                         zStmt);
+    if( zStmt != fulltext_zStatement[iStmt]) sqlite3_free((void *) zStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  } else {
+    int rc = sqlite3_reset(v->pFulltextStatements[iStmt]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  *ppStmt = v->pFulltextStatements[iStmt];
+  return SQLITE_OK;
+}
+
+/* Like sqlite3_step(), but convert SQLITE_DONE to SQLITE_OK and
+** SQLITE_ROW to SQLITE_ERROR.  Useful for statements like UPDATE,
+** where we expect no results.
+*/
+static int sql_single_step(sqlite3_stmt *s){
+  int rc = sqlite3_step(s);
+  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
+}
+
+/* Like sql_get_statement(), but for special replicated LEAF_SELECT
+** statements.
+*/
+/* TODO(shess) Write version for generic statements and then share
+** that between the cached-statement functions.
+*/
+static int sql_get_leaf_statement(fulltext_vtab *v, int idx,
+                                  sqlite3_stmt **ppStmt){
+  assert( idx>=0 && idx<MERGE_COUNT );
+  if( v->pLeafSelectStmts[idx]==NULL ){
+    int rc = sql_prepare(v->db, v->zDb, v->zName, &v->pLeafSelectStmts[idx],
+                         LEAF_SELECT);
+    if( rc!=SQLITE_OK ) return rc;
+  }else{
+    int rc = sqlite3_reset(v->pLeafSelectStmts[idx]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  *ppStmt = v->pLeafSelectStmts[idx];
+  return SQLITE_OK;
+}
+
+/* insert into %_content (docid, ...) values ([docid], [pValues])
+** If the docid contains SQL NULL, then a unique docid will be
+** generated.
+*/
+static int content_insert(fulltext_vtab *v, sqlite3_value *docid,
+                          sqlite3_value **pValues){
+  sqlite3_stmt *s;
+  int i;
+  int rc = sql_get_statement(v, CONTENT_INSERT_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_value(s, 1, docid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  for(i=0; i<v->nColumn; ++i){
+    rc = sqlite3_bind_value(s, 2+i, pValues[i]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  return sql_single_step(s);
+}
+
+/* update %_content set col0 = pValues[0], col1 = pValues[1], ...
+ *                  where docid = [iDocid] */
+static int content_update(fulltext_vtab *v, sqlite3_value **pValues,
+                          sqlite_int64 iDocid){
+  sqlite3_stmt *s;
+  int i;
+  int rc = sql_get_statement(v, CONTENT_UPDATE_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  for(i=0; i<v->nColumn; ++i){
+    rc = sqlite3_bind_value(s, 1+i, pValues[i]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  rc = sqlite3_bind_int64(s, 1+v->nColumn, iDocid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return sql_single_step(s);
+}
+
+static void freeStringArray(int nString, const char **pString){
+  int i;
+
+  for (i=0 ; i < nString ; ++i) {
+    if( pString[i]!=NULL ) sqlite3_free((void *) pString[i]);
+  }
+  sqlite3_free((void *) pString);
+}
+
+/* select * from %_content where docid = [iDocid]
+ * The caller must delete the returned array and all strings in it.
+ * null fields will be NULL in the returned array.
+ *
+ * TODO: Perhaps we should return pointer/length strings here for consistency
+ * with other code which uses pointer/length. */
+static int content_select(fulltext_vtab *v, sqlite_int64 iDocid,
+                          const char ***pValues){
+  sqlite3_stmt *s;
+  const char **values;
+  int i;
+  int rc;
+
+  *pValues = NULL;
+
+  rc = sql_get_statement(v, CONTENT_SELECT_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 1, iDocid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_step(s);
+  if( rc!=SQLITE_ROW ) return rc;
+
+  values = (const char **) sqlite3_malloc(v->nColumn * sizeof(const char *));
+  for(i=0; i<v->nColumn; ++i){
+    if( sqlite3_column_type(s, i)==SQLITE_NULL ){
+      values[i] = NULL;
+    }else{
+      values[i] = string_dup((char*)sqlite3_column_text(s, i));
+    }
+  }
+
+  /* We expect only one row.  We must execute another sqlite3_step()
+   * to complete the iteration; otherwise the table will remain locked. */
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_DONE ){
+    *pValues = values;
+    return SQLITE_OK;
+  }
+
+  freeStringArray(v->nColumn, values);
+  return rc;
+}
+
+/* delete from %_content where docid = [iDocid ] */
+static int content_delete(fulltext_vtab *v, sqlite_int64 iDocid){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, CONTENT_DELETE_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 1, iDocid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return sql_single_step(s);
+}
+
+/* insert into %_segments values ([pData])
+**   returns assigned blockid in *piBlockid
+*/
+static int block_insert(fulltext_vtab *v, const char *pData, int nData,
+                        sqlite_int64 *piBlockid){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, BLOCK_INSERT_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_blob(s, 1, pData, nData, SQLITE_STATIC);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
+  if( rc!=SQLITE_DONE ) return rc;
+
+  /* blockid column is an alias for rowid. */
+  *piBlockid = sqlite3_last_insert_rowid(v->db);
+  return SQLITE_OK;
+}
+
+/* delete from %_segments
+**   where blockid between [iStartBlockid] and [iEndBlockid]
+**
+** Deletes the range of blocks, inclusive, used to delete the blocks
+** which form a segment.
+*/
+static int block_delete(fulltext_vtab *v,
+                        sqlite_int64 iStartBlockid, sqlite_int64 iEndBlockid){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, BLOCK_DELETE_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 1, iStartBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 2, iEndBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return sql_single_step(s);
+}
+
+/* Returns SQLITE_ROW with *pidx set to the maximum segment idx found
+** at iLevel.  Returns SQLITE_DONE if there are no segments at
+** iLevel.  Otherwise returns an error.
+*/
+static int segdir_max_index(fulltext_vtab *v, int iLevel, int *pidx){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, SEGDIR_MAX_INDEX_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int(s, 1, iLevel);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_step(s);
+  /* Should always get at least one row due to how max() works. */
+  if( rc==SQLITE_DONE ) return SQLITE_DONE;
+  if( rc!=SQLITE_ROW ) return rc;
+
+  /* NULL means that there were no inputs to max(). */
+  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
+    rc = sqlite3_step(s);
+    if( rc==SQLITE_ROW ) return SQLITE_ERROR;
+    return rc;
+  }
+
+  *pidx = sqlite3_column_int(s, 0);
+
+  /* We expect only one row.  We must execute another sqlite3_step()
+   * to complete the iteration; otherwise the table will remain locked. */
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
+  if( rc!=SQLITE_DONE ) return rc;
+  return SQLITE_ROW;
+}
+
+/* insert into %_segdir values (
+**   [iLevel], [idx],
+**   [iStartBlockid], [iLeavesEndBlockid], [iEndBlockid],
+**   [pRootData]
+** )
+*/
+static int segdir_set(fulltext_vtab *v, int iLevel, int idx,
+                      sqlite_int64 iStartBlockid,
+                      sqlite_int64 iLeavesEndBlockid,
+                      sqlite_int64 iEndBlockid,
+                      const char *pRootData, int nRootData){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, SEGDIR_SET_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int(s, 1, iLevel);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int(s, 2, idx);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 3, iStartBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 4, iLeavesEndBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 5, iEndBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_blob(s, 6, pRootData, nRootData, SQLITE_STATIC);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return sql_single_step(s);
+}
+
+/* Queries %_segdir for the block span of the segments in level
+** iLevel.  Returns SQLITE_DONE if there are no blocks for iLevel,
+** SQLITE_ROW if there are blocks, else an error.
+*/
+static int segdir_span(fulltext_vtab *v, int iLevel,
+                       sqlite_int64 *piStartBlockid,
+                       sqlite_int64 *piEndBlockid){
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, SEGDIR_SPAN_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int(s, 1, iLevel);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_DONE ) return SQLITE_DONE;  /* Should never happen */
+  if( rc!=SQLITE_ROW ) return rc;
+
+  /* This happens if all segments at this level are entirely inline. */
+  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
+    /* We expect only one row.  We must execute another sqlite3_step()
+     * to complete the iteration; otherwise the table will remain locked. */
+    int rc2 = sqlite3_step(s);
+    if( rc2==SQLITE_ROW ) return SQLITE_ERROR;
+    return rc2;
+  }
+
+  *piStartBlockid = sqlite3_column_int64(s, 0);
+  *piEndBlockid = sqlite3_column_int64(s, 1);
+
+  /* We expect only one row.  We must execute another sqlite3_step()
+   * to complete the iteration; otherwise the table will remain locked. */
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
+  if( rc!=SQLITE_DONE ) return rc;
+  return SQLITE_ROW;
+}
+
+/* Delete the segment blocks and segment directory records for all
+** segments at iLevel.
+*/
+static int segdir_delete(fulltext_vtab *v, int iLevel){
+  sqlite3_stmt *s;
+  sqlite_int64 iStartBlockid, iEndBlockid;
+  int rc = segdir_span(v, iLevel, &iStartBlockid, &iEndBlockid);
+  if( rc!=SQLITE_ROW && rc!=SQLITE_DONE ) return rc;
+
+  if( rc==SQLITE_ROW ){
+    rc = block_delete(v, iStartBlockid, iEndBlockid);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* Delete the segment directory itself. */
+  rc = sql_get_statement(v, SEGDIR_DELETE_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 1, iLevel);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return sql_single_step(s);
+}
+
+/* TODO(shess) clearPendingTerms() is far down the file because
+** writeZeroSegment() is far down the file because LeafWriter is far
+** down the file.  Consider refactoring the code to move the non-vtab
+** code above the vtab code so that we don't need this forward
+** reference.
+*/
+static int clearPendingTerms(fulltext_vtab *v);
+
+/*
+** Free the memory used to contain a fulltext_vtab structure.
+*/
+static void fulltext_vtab_destroy(fulltext_vtab *v){
+  int iStmt, i;
+
+  FTSTRACE(("FTS3 Destroy %p\n", v));
+  for( iStmt=0; iStmt<MAX_STMT; iStmt++ ){
+    if( v->pFulltextStatements[iStmt]!=NULL ){
+      sqlite3_finalize(v->pFulltextStatements[iStmt]);
+      v->pFulltextStatements[iStmt] = NULL;
+    }
+  }
+
+  for( i=0; i<MERGE_COUNT; i++ ){
+    if( v->pLeafSelectStmts[i]!=NULL ){
+      sqlite3_finalize(v->pLeafSelectStmts[i]);
+      v->pLeafSelectStmts[i] = NULL;
+    }
+  }
+
+  if( v->pTokenizer!=NULL ){
+    v->pTokenizer->pModule->xDestroy(v->pTokenizer);
+    v->pTokenizer = NULL;
+  }
+
+  clearPendingTerms(v);
+
+  sqlite3_free(v->azColumn);
+  for(i = 0; i < v->nColumn; ++i) {
+    sqlite3_free(v->azContentColumn[i]);
+  }
+  sqlite3_free(v->azContentColumn);
+  sqlite3_free(v);
+}
+
+/*
+** Token types for parsing the arguments to xConnect or xCreate.
+*/
+#define TOKEN_EOF         0    /* End of file */
+#define TOKEN_SPACE       1    /* Any kind of whitespace */
+#define TOKEN_ID          2    /* An identifier */
+#define TOKEN_STRING      3    /* A string literal */
+#define TOKEN_PUNCT       4    /* A single punctuation character */
+
+/*
+** If X is a character that can be used in an identifier then
+** ftsIdChar(X) will be true.  Otherwise it is false.
+**
+** For ASCII, any character with the high-order bit set is
+** allowed in an identifier.  For 7-bit characters, 
+** isFtsIdChar[X] must be 1.
+**
+** Ticket #1066.  the SQL standard does not allow '$' in the
+** middle of identfiers.  But many SQL implementations do. 
+** SQLite will allow '$' in identifiers for compatibility.
+** But the feature is undocumented.
+*/
+static const char isFtsIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+};
+#define ftsIdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && isFtsIdChar[c-0x20]))
+
+
+/*
+** Return the length of the token that begins at z[0]. 
+** Store the token type in *tokenType before returning.
+*/
+static int ftsGetToken(const char *z, int *tokenType){
+  int i, c;
+  switch( *z ){
+    case 0: {
+      *tokenType = TOKEN_EOF;
+      return 0;
+    }
+    case ' ': case '\t': case '\n': case '\f': case '\r': {
+      for(i=1; safe_isspace(z[i]); i++){}
+      *tokenType = TOKEN_SPACE;
+      return i;
+    }
+    case '`':
+    case '\'':
+    case '"': {
+      int delim = z[0];
+      for(i=1; (c=z[i])!=0; i++){
+        if( c==delim ){
+          if( z[i+1]==delim ){
+            i++;
+          }else{
+            break;
+          }
+        }
+      }
+      *tokenType = TOKEN_STRING;
+      return i + (c!=0);
+    }
+    case '[': {
+      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
+      *tokenType = TOKEN_ID;
+      return i;
+    }
+    default: {
+      if( !ftsIdChar(*z) ){
+        break;
+      }
+      for(i=1; ftsIdChar(z[i]); i++){}
+      *tokenType = TOKEN_ID;
+      return i;
+    }
+  }
+  *tokenType = TOKEN_PUNCT;
+  return 1;
+}
+
+/*
+** A token extracted from a string is an instance of the following
+** structure.
+*/
+typedef struct FtsToken {
+  const char *z;       /* Pointer to token text.  Not '\000' terminated */
+  short int n;         /* Length of the token text in bytes. */
+} FtsToken;
+
+/*
+** Given a input string (which is really one of the argv[] parameters
+** passed into xConnect or xCreate) split the string up into tokens.
+** Return an array of pointers to '\000' terminated strings, one string
+** for each non-whitespace token.
+**
+** The returned array is terminated by a single NULL pointer.
+**
+** Space to hold the returned array is obtained from a single
+** malloc and should be freed by passing the return value to free().
+** The individual strings within the token list are all a part of
+** the single memory allocation and will all be freed at once.
+*/
+static char **tokenizeString(const char *z, int *pnToken){
+  int nToken = 0;
+  FtsToken *aToken = sqlite3_malloc( strlen(z) * sizeof(aToken[0]) );
+  int n = 1;
+  int e, i;
+  int totalSize = 0;
+  char **azToken;
+  char *zCopy;
+  while( n>0 ){
+    n = ftsGetToken(z, &e);
+    if( e!=TOKEN_SPACE ){
+      aToken[nToken].z = z;
+      aToken[nToken].n = n;
+      nToken++;
+      totalSize += n+1;
+    }
+    z += n;
+  }
+  azToken = (char**)sqlite3_malloc( nToken*sizeof(char*) + totalSize );
+  zCopy = (char*)&azToken[nToken];
+  nToken--;
+  for(i=0; i<nToken; i++){
+    azToken[i] = zCopy;
+    n = aToken[i].n;
+    memcpy(zCopy, aToken[i].z, n);
+    zCopy[n] = 0;
+    zCopy += n+1;
+  }
+  azToken[nToken] = 0;
+  sqlite3_free(aToken);
+  *pnToken = nToken;
+  return azToken;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+*/
+static void dequoteString(char *z){
+  int quote;
+  int i, j;
+  if( z==0 ) return;
+  quote = z[0];
+  switch( quote ){
+    case '\'':  break;
+    case '"':   break;
+    case '`':   break;                /* For MySQL compatibility */
+    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
+    default:    return;
+  }
+  for(i=1, j=0; z[i]; i++){
+    if( z[i]==quote ){
+      if( z[i+1]==quote ){
+        z[j++] = quote;
+        i++;
+      }else{
+        z[j++] = 0;
+        break;
+      }
+    }else{
+      z[j++] = z[i];
+    }
+  }
+}
+
+/*
+** The input azIn is a NULL-terminated list of tokens.  Remove the first
+** token and all punctuation tokens.  Remove the quotes from
+** around string literal tokens.
+**
+** Example:
+**
+**     input:      tokenize chinese ( 'simplifed' , 'mixed' )
+**     output:     chinese simplifed mixed
+**
+** Another example:
+**
+**     input:      delimiters ( '[' , ']' , '...' )
+**     output:     [ ] ...
+*/
+static void tokenListToIdList(char **azIn){
+  int i, j;
+  if( azIn ){
+    for(i=0, j=-1; azIn[i]; i++){
+      if( safe_isalnum(azIn[i][0]) || azIn[i][1] ){
+        dequoteString(azIn[i]);
+        if( j>=0 ){
+          azIn[j] = azIn[i];
+        }
+        j++;
+      }
+    }
+    azIn[j] = 0;
+  }
+}
+
+
+/*
+** Find the first alphanumeric token in the string zIn.  Null-terminate
+** this token.  Remove any quotation marks.  And return a pointer to
+** the result.
+*/
+static char *firstToken(char *zIn, char **pzTail){
+  int n, ttype;
+  while(1){
+    n = ftsGetToken(zIn, &ttype);
+    if( ttype==TOKEN_SPACE ){
+      zIn += n;
+    }else if( ttype==TOKEN_EOF ){
+      *pzTail = zIn;
+      return 0;
+    }else{
+      zIn[n] = 0;
+      *pzTail = &zIn[1];
+      dequoteString(zIn);
+      return zIn;
+    }
+  }
+  /*NOTREACHED*/
+}
+
+/* Return true if...
+**
+**   *  s begins with the string t, ignoring case
+**   *  s is longer than t
+**   *  The first character of s beyond t is not a alphanumeric
+** 
+** Ignore leading space in *s.
+**
+** To put it another way, return true if the first token of
+** s[] is t[].
+*/
+static int startsWith(const char *s, const char *t){
+  while( safe_isspace(*s) ){ s++; }
+  while( *t ){
+    if( safe_tolower(*s++)!=safe_tolower(*t++) ) return 0;
+  }
+  return *s!='_' && !safe_isalnum(*s);
+}
+
+/*
+** An instance of this structure defines the "spec" of a
+** full text index.  This structure is populated by parseSpec
+** and use by fulltextConnect and fulltextCreate.
+*/
+typedef struct TableSpec {
+  const char *zDb;         /* Logical database name */
+  const char *zName;       /* Name of the full-text index */
+  int nColumn;             /* Number of columns to be indexed */
+  char **azColumn;         /* Original names of columns to be indexed */
+  char **azContentColumn;  /* Column names for %_content */
+  char **azTokenizer;      /* Name of tokenizer and its arguments */
+} TableSpec;
+
+/*
+** Reclaim all of the memory used by a TableSpec
+*/
+static void clearTableSpec(TableSpec *p) {
+  sqlite3_free(p->azColumn);
+  sqlite3_free(p->azContentColumn);
+  sqlite3_free(p->azTokenizer);
+}
+
+/* Parse a CREATE VIRTUAL TABLE statement, which looks like this:
+ *
+ * CREATE VIRTUAL TABLE email
+ *        USING fts3(subject, body, tokenize mytokenizer(myarg))
+ *
+ * We return parsed information in a TableSpec structure.
+ * 
+ */
+static int parseSpec(TableSpec *pSpec, int argc, const char *const*argv,
+                     char**pzErr){
+  int i, n;
+  char *z, *zDummy;
+  char **azArg;
+  const char *zTokenizer = 0;    /* argv[] entry describing the tokenizer */
+
+  assert( argc>=3 );
+  /* Current interface:
+  ** argv[0] - module name
+  ** argv[1] - database name
+  ** argv[2] - table name
+  ** argv[3..] - columns, optionally followed by tokenizer specification
+  **             and snippet delimiters specification.
+  */
+
+  /* Make a copy of the complete argv[][] array in a single allocation.
+  ** The argv[][] array is read-only and transient.  We can write to the
+  ** copy in order to modify things and the copy is persistent.
+  */
+  CLEAR(pSpec);
+  for(i=n=0; i<argc; i++){
+    n += strlen(argv[i]) + 1;
+  }
+  azArg = sqlite3_malloc( sizeof(char*)*argc + n );
+  if( azArg==0 ){
+    return SQLITE_NOMEM;
+  }
+  z = (char*)&azArg[argc];
+  for(i=0; i<argc; i++){
+    azArg[i] = z;
+    strcpy(z, argv[i]);
+    z += strlen(z)+1;
+  }
+
+  /* Identify the column names and the tokenizer and delimiter arguments
+  ** in the argv[][] array.
+  */
+  pSpec->zDb = azArg[1];
+  pSpec->zName = azArg[2];
+  pSpec->nColumn = 0;
+  pSpec->azColumn = azArg;
+  zTokenizer = "tokenize simple";
+  for(i=3; i<argc; ++i){
+    if( startsWith(azArg[i],"tokenize") ){
+      zTokenizer = azArg[i];
+    }else{
+      z = azArg[pSpec->nColumn] = firstToken(azArg[i], &zDummy);
+      pSpec->nColumn++;
+    }
+  }
+  if( pSpec->nColumn==0 ){
+    azArg[0] = "content";
+    pSpec->nColumn = 1;
+  }
+
+  /*
+  ** Construct the list of content column names.
+  **
+  ** Each content column name will be of the form cNNAAAA
+  ** where NN is the column number and AAAA is the sanitized
+  ** column name.  "sanitized" means that special characters are
+  ** converted to "_".  The cNN prefix guarantees that all column
+  ** names are unique.
+  **
+  ** The AAAA suffix is not strictly necessary.  It is included
+  ** for the convenience of people who might examine the generated
+  ** %_content table and wonder what the columns are used for.
+  */
+  pSpec->azContentColumn = sqlite3_malloc( pSpec->nColumn * sizeof(char *) );
+  if( pSpec->azContentColumn==0 ){
+    clearTableSpec(pSpec);
+    return SQLITE_NOMEM;
+  }
+  for(i=0; i<pSpec->nColumn; i++){
+    char *p;
+    pSpec->azContentColumn[i] = sqlite3_mprintf("c%d%s", i, azArg[i]);
+    for (p = pSpec->azContentColumn[i]; *p ; ++p) {
+      if( !safe_isalnum(*p) ) *p = '_';
+    }
+  }
+
+  /*
+  ** Parse the tokenizer specification string.
+  */
+  pSpec->azTokenizer = tokenizeString(zTokenizer, &n);
+  tokenListToIdList(pSpec->azTokenizer);
+
+  return SQLITE_OK;
+}
+
+/*
+** Generate a CREATE TABLE statement that describes the schema of
+** the virtual table.  Return a pointer to this schema string.
+**
+** Space is obtained from sqlite3_mprintf() and should be freed
+** using sqlite3_free().
+*/
+static char *fulltextSchema(
+  int nColumn,                  /* Number of columns */
+  const char *const* azColumn,  /* List of columns */
+  const char *zTableName        /* Name of the table */
+){
+  int i;
+  char *zSchema, *zNext;
+  const char *zSep = "(";
+  zSchema = sqlite3_mprintf("CREATE TABLE x");
+  for(i=0; i<nColumn; i++){
+    zNext = sqlite3_mprintf("%s%s%Q", zSchema, zSep, azColumn[i]);
+    sqlite3_free(zSchema);
+    zSchema = zNext;
+    zSep = ",";
+  }
+  zNext = sqlite3_mprintf("%s,%Q HIDDEN", zSchema, zTableName);
+  sqlite3_free(zSchema);
+  zSchema = zNext;
+  zNext = sqlite3_mprintf("%s,docid HIDDEN)", zSchema);
+  sqlite3_free(zSchema);
+  return zNext;
+}
+
+/*
+** Build a new sqlite3_vtab structure that will describe the
+** fulltext index defined by spec.
+*/
+static int constructVtab(
+  sqlite3 *db,              /* The SQLite database connection */
+  fts3Hash *pHash,          /* Hash table containing tokenizers */
+  TableSpec *spec,          /* Parsed spec information from parseSpec() */
+  sqlite3_vtab **ppVTab,    /* Write the resulting vtab structure here */
+  char **pzErr              /* Write any error message here */
+){
+  int rc;
+  int n;
+  fulltext_vtab *v = 0;
+  const sqlite3_tokenizer_module *m = NULL;
+  char *schema;
+
+  char const *zTok;         /* Name of tokenizer to use for this fts table */
+  int nTok;                 /* Length of zTok, including nul terminator */
+
+  v = (fulltext_vtab *) sqlite3_malloc(sizeof(fulltext_vtab));
+  if( v==0 ) return SQLITE_NOMEM;
+  CLEAR(v);
+  /* sqlite will initialize v->base */
+  v->db = db;
+  v->zDb = spec->zDb;       /* Freed when azColumn is freed */
+  v->zName = spec->zName;   /* Freed when azColumn is freed */
+  v->nColumn = spec->nColumn;
+  v->azContentColumn = spec->azContentColumn;
+  spec->azContentColumn = 0;
+  v->azColumn = spec->azColumn;
+  spec->azColumn = 0;
+
+  if( spec->azTokenizer==0 ){
+    return SQLITE_NOMEM;
+  }
+
+  zTok = spec->azTokenizer[0]; 
+  if( !zTok ){
+    zTok = "simple";
+  }
+  nTok = strlen(zTok)+1;
+
+  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zTok, nTok);
+  if( !m ){
+    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", spec->azTokenizer[0]);
+    rc = SQLITE_ERROR;
+    goto err;
+  }
+
+  for(n=0; spec->azTokenizer[n]; n++){}
+  if( n ){
+    rc = m->xCreate(n-1, (const char*const*)&spec->azTokenizer[1],
+                    &v->pTokenizer);
+  }else{
+    rc = m->xCreate(0, 0, &v->pTokenizer);
+  }
+  if( rc!=SQLITE_OK ) goto err;
+  v->pTokenizer->pModule = m;
+
+  /* TODO: verify the existence of backing tables foo_content, foo_term */
+
+  schema = fulltextSchema(v->nColumn, (const char*const*)v->azColumn,
+                          spec->zName);
+  rc = sqlite3_declare_vtab(db, schema);
+  sqlite3_free(schema);
+  if( rc!=SQLITE_OK ) goto err;
+
+  memset(v->pFulltextStatements, 0, sizeof(v->pFulltextStatements));
+
+  /* Indicate that the buffer is not live. */
+  v->nPendingData = -1;
+
+  *ppVTab = &v->base;
+  FTSTRACE(("FTS3 Connect %p\n", v));
+
+  return rc;
+
+err:
+  fulltext_vtab_destroy(v);
+  return rc;
+}
+
+static int fulltextConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVTab,
+  char **pzErr
+){
+  TableSpec spec;
+  int rc = parseSpec(&spec, argc, argv, pzErr);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
+  clearTableSpec(&spec);
+  return rc;
+}
+
+/* The %_content table holds the text of each document, with
+** the docid column exposed as the SQLite rowid for the table.
+*/
+/* TODO(shess) This comment needs elaboration to match the updated
+** code.  Work it into the top-of-file comment at that time.
+*/
+static int fulltextCreate(sqlite3 *db, void *pAux,
+                          int argc, const char * const *argv,
+                          sqlite3_vtab **ppVTab, char **pzErr){
+  int rc;
+  TableSpec spec;
+  StringBuffer schema;
+  FTSTRACE(("FTS3 Create\n"));
+
+  rc = parseSpec(&spec, argc, argv, pzErr);
+  if( rc!=SQLITE_OK ) return rc;
+
+  initStringBuffer(&schema);
+  append(&schema, "CREATE TABLE %_content(");
+  append(&schema, "  docid INTEGER PRIMARY KEY,");
+  appendList(&schema, spec.nColumn, spec.azContentColumn);
+  append(&schema, ")");
+  rc = sql_exec(db, spec.zDb, spec.zName, stringBufferData(&schema));
+  stringBufferDestroy(&schema);
+  if( rc!=SQLITE_OK ) goto out;
+
+  rc = sql_exec(db, spec.zDb, spec.zName,
+                "create table %_segments("
+                "  blockid INTEGER PRIMARY KEY,"
+                "  block blob"
+                ");"
+                );
+  if( rc!=SQLITE_OK ) goto out;
+
+  rc = sql_exec(db, spec.zDb, spec.zName,
+                "create table %_segdir("
+                "  level integer,"
+                "  idx integer,"
+                "  start_block integer,"
+                "  leaves_end_block integer,"
+                "  end_block integer,"
+                "  root blob,"
+                "  primary key(level, idx)"
+                ");");
+  if( rc!=SQLITE_OK ) goto out;
+
+  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
+
+out:
+  clearTableSpec(&spec);
+  return rc;
+}
+
+/* Decide how to handle an SQL query. */
+static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  fulltext_vtab *v = (fulltext_vtab *)pVTab;
+  int i;
+  FTSTRACE(("FTS3 BestIndex\n"));
+
+  for(i=0; i<pInfo->nConstraint; ++i){
+    const struct sqlite3_index_constraint *pConstraint;
+    pConstraint = &pInfo->aConstraint[i];
+    if( pConstraint->usable ) {
+      if( (pConstraint->iColumn==-1 || pConstraint->iColumn==v->nColumn+1) &&
+          pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+        pInfo->idxNum = QUERY_DOCID;      /* lookup by docid */
+        FTSTRACE(("FTS3 QUERY_DOCID\n"));
+      } else if( pConstraint->iColumn>=0 && pConstraint->iColumn<=v->nColumn &&
+                 pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
+        /* full-text search */
+        pInfo->idxNum = QUERY_FULLTEXT + pConstraint->iColumn;
+        FTSTRACE(("FTS3 QUERY_FULLTEXT %d\n", pConstraint->iColumn));
+      } else continue;
+
+      pInfo->aConstraintUsage[i].argvIndex = 1;
+      pInfo->aConstraintUsage[i].omit = 1;
+
+      /* An arbitrary value for now.
+       * TODO: Perhaps docid matches should be considered cheaper than
+       * full-text searches. */
+      pInfo->estimatedCost = 1.0;   
+
+      return SQLITE_OK;
+    }
+  }
+  pInfo->idxNum = QUERY_GENERIC;
+  return SQLITE_OK;
+}
+
+static int fulltextDisconnect(sqlite3_vtab *pVTab){
+  FTSTRACE(("FTS3 Disconnect %p\n", pVTab));
+  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
+  return SQLITE_OK;
+}
+
+static int fulltextDestroy(sqlite3_vtab *pVTab){
+  fulltext_vtab *v = (fulltext_vtab *)pVTab;
+  int rc;
+
+  FTSTRACE(("FTS3 Destroy %p\n", pVTab));
+  rc = sql_exec(v->db, v->zDb, v->zName,
+                "drop table if exists %_content;"
+                "drop table if exists %_segments;"
+                "drop table if exists %_segdir;"
+                );
+  if( rc!=SQLITE_OK ) return rc;
+
+  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
+  return SQLITE_OK;
+}
+
+static int fulltextOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  fulltext_cursor *c;
+
+  c = (fulltext_cursor *) sqlite3_malloc(sizeof(fulltext_cursor));
+  if( c ){
+    memset(c, 0, sizeof(fulltext_cursor));
+    /* sqlite will initialize c->base */
+    *ppCursor = &c->base;
+    FTSTRACE(("FTS3 Open %p: %p\n", pVTab, c));
+    return SQLITE_OK;
+  }else{
+    return SQLITE_NOMEM;
+  }
+}
+
+
+/* Free all of the dynamically allocated memory held by *q
+*/
+static void queryClear(Query *q){
+  int i;
+  for(i = 0; i < q->nTerms; ++i){
+    sqlite3_free(q->pTerms[i].pTerm);
+  }
+  sqlite3_free(q->pTerms);
+  CLEAR(q);
+}
+
+/* Free all of the dynamically allocated memory held by the
+** Snippet
+*/
+static void snippetClear(Snippet *p){
+  sqlite3_free(p->aMatch);
+  sqlite3_free(p->zOffset);
+  sqlite3_free(p->zSnippet);
+  CLEAR(p);
+}
+/*
+** Append a single entry to the p->aMatch[] log.
+*/
+static void snippetAppendMatch(
+  Snippet *p,               /* Append the entry to this snippet */
+  int iCol, int iTerm,      /* The column and query term */
+  int iToken,               /* Matching token in document */
+  int iStart, int nByte     /* Offset and size of the match */
+){
+  int i;
+  struct snippetMatch *pMatch;
+  if( p->nMatch+1>=p->nAlloc ){
+    p->nAlloc = p->nAlloc*2 + 10;
+    p->aMatch = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
+    if( p->aMatch==0 ){
+      p->nMatch = 0;
+      p->nAlloc = 0;
+      return;
+    }
+  }
+  i = p->nMatch++;
+  pMatch = &p->aMatch[i];
+  pMatch->iCol = iCol;
+  pMatch->iTerm = iTerm;
+  pMatch->iToken = iToken;
+  pMatch->iStart = iStart;
+  pMatch->nByte = nByte;
+}
+
+/*
+** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
+*/
+#define FTS3_ROTOR_SZ   (32)
+#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)
+
+/*
+** Add entries to pSnippet->aMatch[] for every match that occurs against
+** document zDoc[0..nDoc-1] which is stored in column iColumn.
+*/
+static void snippetOffsetsOfColumn(
+  Query *pQuery,
+  Snippet *pSnippet,
+  int iColumn,
+  const char *zDoc,
+  int nDoc
+){
+  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
+  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
+  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
+  fulltext_vtab *pVtab;                /* The full text index */
+  int nColumn;                         /* Number of columns in the index */
+  const QueryTerm *aTerm;              /* Query string terms */
+  int nTerm;                           /* Number of query string terms */  
+  int i, j;                            /* Loop counters */
+  int rc;                              /* Return code */
+  unsigned int match, prevMatch;       /* Phrase search bitmasks */
+  const char *zToken;                  /* Next token from the tokenizer */
+  int nToken;                          /* Size of zToken */
+  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */
+
+  /* The following variables keep a circular buffer of the last
+  ** few tokens */
+  unsigned int iRotor = 0;             /* Index of current token */
+  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
+  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */
+
+  pVtab = pQuery->pFts;
+  nColumn = pVtab->nColumn;
+  pTokenizer = pVtab->pTokenizer;
+  pTModule = pTokenizer->pModule;
+  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
+  if( rc ) return;
+  pTCursor->pTokenizer = pTokenizer;
+  aTerm = pQuery->pTerms;
+  nTerm = pQuery->nTerms;
+  if( nTerm>=FTS3_ROTOR_SZ ){
+    nTerm = FTS3_ROTOR_SZ - 1;
+  }
+  prevMatch = 0;
+  while(1){
+    rc = pTModule->xNext(pTCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos);
+    if( rc ) break;
+    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
+    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
+    match = 0;
+    for(i=0; i<nTerm; i++){
+      int iCol;
+      iCol = aTerm[i].iColumn;
+      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
+      if( aTerm[i].nTerm>nToken ) continue;
+      if( !aTerm[i].isPrefix && aTerm[i].nTerm<nToken ) continue;
+      assert( aTerm[i].nTerm<=nToken );
+      if( memcmp(aTerm[i].pTerm, zToken, aTerm[i].nTerm) ) continue;
+      if( aTerm[i].iPhrase>1 && (prevMatch & (1<<i))==0 ) continue;
+      match |= 1<<i;
+      if( i==nTerm-1 || aTerm[i+1].iPhrase==1 ){
+        for(j=aTerm[i].iPhrase-1; j>=0; j--){
+          int k = (iRotor-j) & FTS3_ROTOR_MASK;
+          snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
+                iRotorBegin[k], iRotorLen[k]);
+        }
+      }
+    }
+    prevMatch = match<<1;
+    iRotor++;
+  }
+  pTModule->xClose(pTCursor);  
+}
+
+/*
+** Remove entries from the pSnippet structure to account for the NEAR
+** operator. When this is called, pSnippet contains the list of token 
+** offsets produced by treating all NEAR operators as AND operators.
+** This function removes any entries that should not be present after
+** accounting for the NEAR restriction. For example, if the queried
+** document is:
+**
+**     "A B C D E A"
+**
+** and the query is:
+** 
+**     A NEAR/0 E
+**
+** then when this function is called the Snippet contains token offsets
+** 0, 4 and 5. This function removes the "0" entry (because the first A
+** is not near enough to an E).
+*/
+static void trimSnippetOffsetsForNear(Query *pQuery, Snippet *pSnippet){
+  int ii;
+  int iDir = 1;
+
+  while(iDir>-2) {
+    assert( iDir==1 || iDir==-1 );
+    for(ii=0; ii<pSnippet->nMatch; ii++){
+      int jj;
+      int nNear;
+      struct snippetMatch *pMatch = &pSnippet->aMatch[ii];
+      QueryTerm *pQueryTerm = &pQuery->pTerms[pMatch->iTerm];
+
+      if( (pMatch->iTerm+iDir)<0 
+       || (pMatch->iTerm+iDir)>=pQuery->nTerms
+      ){
+        continue;
+      }
+     
+      nNear = pQueryTerm->nNear;
+      if( iDir<0 ){
+        nNear = pQueryTerm[-1].nNear;
+      }
+  
+      if( pMatch->iTerm>=0 && nNear ){
+        int isOk = 0;
+        int iNextTerm = pMatch->iTerm+iDir;
+        int iPrevTerm = iNextTerm;
+
+        int iEndToken;
+        int iStartToken;
+
+        if( iDir<0 ){
+          int nPhrase = 1;
+          iStartToken = pMatch->iToken;
+          while( (pMatch->iTerm+nPhrase)<pQuery->nTerms 
+              && pQuery->pTerms[pMatch->iTerm+nPhrase].iPhrase>1 
+          ){
+            nPhrase++;
+          }
+          iEndToken = iStartToken + nPhrase - 1;
+        }else{
+          iEndToken   = pMatch->iToken;
+          iStartToken = pMatch->iToken+1-pQueryTerm->iPhrase;
+        }
+
+        while( pQuery->pTerms[iNextTerm].iPhrase>1 ){
+          iNextTerm--;
+        }
+        while( (iPrevTerm+1)<pQuery->nTerms && 
+               pQuery->pTerms[iPrevTerm+1].iPhrase>1 
+        ){
+          iPrevTerm++;
+        }
+  
+        for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
+          struct snippetMatch *p = &pSnippet->aMatch[jj];
+          if( p->iCol==pMatch->iCol && ((
+               p->iTerm==iNextTerm && 
+               p->iToken>iEndToken && 
+               p->iToken<=iEndToken+nNear
+          ) || (
+               p->iTerm==iPrevTerm && 
+               p->iToken<iStartToken && 
+               p->iToken>=iStartToken-nNear
+          ))){
+            isOk = 1;
+          }
+        }
+        if( !isOk ){
+          for(jj=1-pQueryTerm->iPhrase; jj<=0; jj++){
+            pMatch[jj].iTerm = -1;
+          }
+          ii = -1;
+          iDir = 1;
+        }
+      }
+    }
+    iDir -= 2;
+  }
+}
+
+/*
+** Compute all offsets for the current row of the query.  
+** If the offsets have already been computed, this routine is a no-op.
+*/
+static void snippetAllOffsets(fulltext_cursor *p){
+  int nColumn;
+  int iColumn, i;
+  int iFirst, iLast;
+  fulltext_vtab *pFts;
+
+  if( p->snippet.nMatch ) return;
+  if( p->q.nTerms==0 ) return;
+  pFts = p->q.pFts;
+  nColumn = pFts->nColumn;
+  iColumn = (p->iCursorType - QUERY_FULLTEXT);
+  if( iColumn<0 || iColumn>=nColumn ){
+    iFirst = 0;
+    iLast = nColumn-1;
+  }else{
+    iFirst = iColumn;
+    iLast = iColumn;
+  }
+  for(i=iFirst; i<=iLast; i++){
+    const char *zDoc;
+    int nDoc;
+    zDoc = (const char*)sqlite3_column_text(p->pStmt, i+1);
+    nDoc = sqlite3_column_bytes(p->pStmt, i+1);
+    snippetOffsetsOfColumn(&p->q, &p->snippet, i, zDoc, nDoc);
+  }
+
+  trimSnippetOffsetsForNear(&p->q, &p->snippet);
+}
+
+/*
+** Convert the information in the aMatch[] array of the snippet
+** into the string zOffset[0..nOffset-1].
+*/
+static void snippetOffsetText(Snippet *p){
+  int i;
+  int cnt = 0;
+  StringBuffer sb;
+  char zBuf[200];
+  if( p->zOffset ) return;
+  initStringBuffer(&sb);
+  for(i=0; i<p->nMatch; i++){
+    struct snippetMatch *pMatch = &p->aMatch[i];
+    if( pMatch->iTerm>=0 ){
+      /* If snippetMatch.iTerm is less than 0, then the match was 
+      ** discarded as part of processing the NEAR operator (see the 
+      ** trimSnippetOffsetsForNear() function for details). Ignore 
+      ** it in this case
+      */
+      zBuf[0] = ' ';
+      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
+          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
+      append(&sb, zBuf);
+      cnt++;
+    }
+  }
+  p->zOffset = stringBufferData(&sb);
+  p->nOffset = stringBufferLength(&sb);
+}
+
+/*
+** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
+** of matching words some of which might be in zDoc.  zDoc is column
+** number iCol.
+**
+** iBreak is suggested spot in zDoc where we could begin or end an
+** excerpt.  Return a value similar to iBreak but possibly adjusted
+** to be a little left or right so that the break point is better.
+*/
+static int wordBoundary(
+  int iBreak,                   /* The suggested break point */
+  const char *zDoc,             /* Document text */
+  int nDoc,                     /* Number of bytes in zDoc[] */
+  struct snippetMatch *aMatch,  /* Matching words */
+  int nMatch,                   /* Number of entries in aMatch[] */
+  int iCol                      /* The column number for zDoc[] */
+){
+  int i;
+  if( iBreak<=10 ){
+    return 0;
+  }
+  if( iBreak>=nDoc-10 ){
+    return nDoc;
+  }
+  for(i=0; i<nMatch && aMatch[i].iCol<iCol; i++){}
+  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
+  if( i<nMatch ){
+    if( aMatch[i].iStart<iBreak+10 ){
+      return aMatch[i].iStart;
+    }
+    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
+      return aMatch[i-1].iStart;
+    }
+  }
+  for(i=1; i<=10; i++){
+    if( safe_isspace(zDoc[iBreak-i]) ){
+      return iBreak - i + 1;
+    }
+    if( safe_isspace(zDoc[iBreak+i]) ){
+      return iBreak + i + 1;
+    }
+  }
+  return iBreak;
+}
+
+
+
+/*
+** Allowed values for Snippet.aMatch[].snStatus
+*/
+#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
+#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */
+
+/*
+** Generate the text of a snippet.
+*/
+static void snippetText(
+  fulltext_cursor *pCursor,   /* The cursor we need the snippet for */
+  const char *zStartMark,     /* Markup to appear before each match */
+  const char *zEndMark,       /* Markup to appear after each match */
+  const char *zEllipsis       /* Ellipsis mark */
+){
+  int i, j;
+  struct snippetMatch *aMatch;
+  int nMatch;
+  int nDesired;
+  StringBuffer sb;
+  int tailCol;
+  int tailOffset;
+  int iCol;
+  int nDoc;
+  const char *zDoc;
+  int iStart, iEnd;
+  int tailEllipsis = 0;
+  int iMatch;
+  
+
+  sqlite3_free(pCursor->snippet.zSnippet);
+  pCursor->snippet.zSnippet = 0;
+  aMatch = pCursor->snippet.aMatch;
+  nMatch = pCursor->snippet.nMatch;
+  initStringBuffer(&sb);
+
+  for(i=0; i<nMatch; i++){
+    aMatch[i].snStatus = SNIPPET_IGNORE;
+  }
+  nDesired = 0;
+  for(i=0; i<pCursor->q.nTerms; i++){
+    for(j=0; j<nMatch; j++){
+      if( aMatch[j].iTerm==i ){
+        aMatch[j].snStatus = SNIPPET_DESIRED;
+        nDesired++;
+        break;
+      }
+    }
+  }
+
+  iMatch = 0;
+  tailCol = -1;
+  tailOffset = 0;
+  for(i=0; i<nMatch && nDesired>0; i++){
+    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
+    nDesired--;
+    iCol = aMatch[i].iCol;
+    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
+    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
+    iStart = aMatch[i].iStart - 40;
+    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
+    if( iStart<=10 ){
+      iStart = 0;
+    }
+    if( iCol==tailCol && iStart<=tailOffset+20 ){
+      iStart = tailOffset;
+    }
+    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
+      trimWhiteSpace(&sb);
+      appendWhiteSpace(&sb);
+      append(&sb, zEllipsis);
+      appendWhiteSpace(&sb);
+    }
+    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
+    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
+    if( iEnd>=nDoc-10 ){
+      iEnd = nDoc;
+      tailEllipsis = 0;
+    }else{
+      tailEllipsis = 1;
+    }
+    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
+    while( iStart<iEnd ){
+      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
+             && aMatch[iMatch].iCol<=iCol ){
+        iMatch++;
+      }
+      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
+             && aMatch[iMatch].iCol==iCol ){
+        nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
+        iStart = aMatch[iMatch].iStart;
+        append(&sb, zStartMark);
+        nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
+        append(&sb, zEndMark);
+        iStart += aMatch[iMatch].nByte;
+        for(j=iMatch+1; j<nMatch; j++){
+          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
+              && aMatch[j].snStatus==SNIPPET_DESIRED ){
+            nDesired--;
+            aMatch[j].snStatus = SNIPPET_IGNORE;
+          }
+        }
+      }else{
+        nappend(&sb, &zDoc[iStart], iEnd - iStart);
+        iStart = iEnd;
+      }
+    }
+    tailCol = iCol;
+    tailOffset = iEnd;
+  }
+  trimWhiteSpace(&sb);
+  if( tailEllipsis ){
+    appendWhiteSpace(&sb);
+    append(&sb, zEllipsis);
+  }
+  pCursor->snippet.zSnippet = stringBufferData(&sb);
+  pCursor->snippet.nSnippet = stringBufferLength(&sb);
+}
+
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fulltextClose(sqlite3_vtab_cursor *pCursor){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+  FTSTRACE(("FTS3 Close %p\n", c));
+  sqlite3_finalize(c->pStmt);
+  queryClear(&c->q);
+  snippetClear(&c->snippet);
+  if( c->result.nData!=0 ) dlrDestroy(&c->reader);
+  dataBufferDestroy(&c->result);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+
+static int fulltextNext(sqlite3_vtab_cursor *pCursor){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+  int rc;
+
+  FTSTRACE(("FTS3 Next %p\n", pCursor));
+  snippetClear(&c->snippet);
+  if( c->iCursorType < QUERY_FULLTEXT ){
+    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
+    rc = sqlite3_step(c->pStmt);
+    switch( rc ){
+      case SQLITE_ROW:
+        c->eof = 0;
+        return SQLITE_OK;
+      case SQLITE_DONE:
+        c->eof = 1;
+        return SQLITE_OK;
+      default:
+        c->eof = 1;
+        return rc;
+    }
+  } else {  /* full-text query */
+    rc = sqlite3_reset(c->pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+
+    if( c->result.nData==0 || dlrAtEnd(&c->reader) ){
+      c->eof = 1;
+      return SQLITE_OK;
+    }
+    rc = sqlite3_bind_int64(c->pStmt, 1, dlrDocid(&c->reader));
+    dlrStep(&c->reader);
+    if( rc!=SQLITE_OK ) return rc;
+    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
+    rc = sqlite3_step(c->pStmt);
+    if( rc==SQLITE_ROW ){   /* the case we expect */
+      c->eof = 0;
+      return SQLITE_OK;
+    }
+    /* an error occurred; abort */
+    return rc==SQLITE_DONE ? SQLITE_ERROR : rc;
+  }
+}
+
+
+/* TODO(shess) If we pushed LeafReader to the top of the file, or to
+** another file, term_select() could be pushed above
+** docListOfTerm().
+*/
+static int termSelect(fulltext_vtab *v, int iColumn,
+                      const char *pTerm, int nTerm, int isPrefix,
+                      DocListType iType, DataBuffer *out);
+
+/* Return a DocList corresponding to the query term *pTerm.  If *pTerm
+** is the first term of a phrase query, go ahead and evaluate the phrase
+** query and return the doclist for the entire phrase query.
+**
+** The resulting DL_DOCIDS doclist is stored in pResult, which is
+** overwritten.
+*/
+static int docListOfTerm(
+  fulltext_vtab *v,    /* The full text index */
+  int iColumn,         /* column to restrict to.  No restriction if >=nColumn */
+  QueryTerm *pQTerm,   /* Term we are looking for, or 1st term of a phrase */
+  DataBuffer *pResult  /* Write the result here */
+){
+  DataBuffer left, right, new;
+  int i, rc;
+
+  /* No phrase search if no position info. */
+  assert( pQTerm->nPhrase==0 || DL_DEFAULT!=DL_DOCIDS );
+
+  /* This code should never be called with buffered updates. */
+  assert( v->nPendingData<0 );
+
+  dataBufferInit(&left, 0);
+  rc = termSelect(v, iColumn, pQTerm->pTerm, pQTerm->nTerm, pQTerm->isPrefix,
+                  (0<pQTerm->nPhrase ? DL_POSITIONS : DL_DOCIDS), &left);
+  if( rc ) return rc;
+  for(i=1; i<=pQTerm->nPhrase && left.nData>0; i++){
+    /* If this token is connected to the next by a NEAR operator, and
+    ** the next token is the start of a phrase, then set nPhraseRight
+    ** to the number of tokens in the phrase. Otherwise leave it at 1.
+    */
+    int nPhraseRight = 1;
+    while( (i+nPhraseRight)<=pQTerm->nPhrase 
+        && pQTerm[i+nPhraseRight].nNear==0 
+    ){
+      nPhraseRight++;
+    }
+
+    dataBufferInit(&right, 0);
+    rc = termSelect(v, iColumn, pQTerm[i].pTerm, pQTerm[i].nTerm,
+                    pQTerm[i].isPrefix, DL_POSITIONS, &right);
+    if( rc ){
+      dataBufferDestroy(&left);
+      return rc;
+    }
+    dataBufferInit(&new, 0);
+    docListPhraseMerge(left.pData, left.nData, right.pData, right.nData,
+                       pQTerm[i-1].nNear, pQTerm[i-1].iPhrase + nPhraseRight,
+                       ((i<pQTerm->nPhrase) ? DL_POSITIONS : DL_DOCIDS),
+                       &new);
+    dataBufferDestroy(&left);
+    dataBufferDestroy(&right);
+    left = new;
+  }
+  *pResult = left;
+  return SQLITE_OK;
+}
+
+/* Add a new term pTerm[0..nTerm-1] to the query *q.
+*/
+static void queryAdd(Query *q, const char *pTerm, int nTerm){
+  QueryTerm *t;
+  ++q->nTerms;
+  q->pTerms = sqlite3_realloc(q->pTerms, q->nTerms * sizeof(q->pTerms[0]));
+  if( q->pTerms==0 ){
+    q->nTerms = 0;
+    return;
+  }
+  t = &q->pTerms[q->nTerms - 1];
+  CLEAR(t);
+  t->pTerm = sqlite3_malloc(nTerm+1);
+  memcpy(t->pTerm, pTerm, nTerm);
+  t->pTerm[nTerm] = 0;
+  t->nTerm = nTerm;
+  t->isOr = q->nextIsOr;
+  t->isPrefix = 0;
+  q->nextIsOr = 0;
+  t->iColumn = q->nextColumn;
+  q->nextColumn = q->dfltColumn;
+}
+
+/*
+** Check to see if the string zToken[0...nToken-1] matches any
+** column name in the virtual table.   If it does,
+** return the zero-indexed column number.  If not, return -1.
+*/
+static int checkColumnSpecifier(
+  fulltext_vtab *pVtab,    /* The virtual table */
+  const char *zToken,      /* Text of the token */
+  int nToken               /* Number of characters in the token */
+){
+  int i;
+  for(i=0; i<pVtab->nColumn; i++){
+    if( memcmp(pVtab->azColumn[i], zToken, nToken)==0
+        && pVtab->azColumn[i][nToken]==0 ){
+      return i;
+    }
+  }
+  return -1;
+}
+
+/*
+** Parse the text at pSegment[0..nSegment-1].  Add additional terms
+** to the query being assemblied in pQuery.
+**
+** inPhrase is true if pSegment[0..nSegement-1] is contained within
+** double-quotes.  If inPhrase is true, then the first term
+** is marked with the number of terms in the phrase less one and
+** OR and "-" syntax is ignored.  If inPhrase is false, then every
+** term found is marked with nPhrase=0 and OR and "-" syntax is significant.
+*/
+static int tokenizeSegment(
+  sqlite3_tokenizer *pTokenizer,          /* The tokenizer to use */
+  const char *pSegment, int nSegment,     /* Query expression being parsed */
+  int inPhrase,                           /* True if within "..." */
+  Query *pQuery                           /* Append results here */
+){
+  const sqlite3_tokenizer_module *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCursor;
+  int firstIndex = pQuery->nTerms;
+  int iCol;
+  int nTerm = 1;
+  
+  int rc = pModule->xOpen(pTokenizer, pSegment, nSegment, &pCursor);
+  if( rc!=SQLITE_OK ) return rc;
+  pCursor->pTokenizer = pTokenizer;
+
+  while( 1 ){
+    const char *pToken;
+    int nToken, iBegin, iEnd, iPos;
+
+    rc = pModule->xNext(pCursor,
+                        &pToken, &nToken,
+                        &iBegin, &iEnd, &iPos);
+    if( rc!=SQLITE_OK ) break;
+    if( !inPhrase &&
+        pSegment[iEnd]==':' &&
+         (iCol = checkColumnSpecifier(pQuery->pFts, pToken, nToken))>=0 ){
+      pQuery->nextColumn = iCol;
+      continue;
+    }
+    if( !inPhrase && pQuery->nTerms>0 && nToken==2 
+     && pSegment[iBegin+0]=='O'
+     && pSegment[iBegin+1]=='R' 
+    ){
+      pQuery->nextIsOr = 1;
+      continue;
+    }
+    if( !inPhrase && pQuery->nTerms>0 && !pQuery->nextIsOr && nToken==4 
+      && pSegment[iBegin+0]=='N' 
+      && pSegment[iBegin+1]=='E' 
+      && pSegment[iBegin+2]=='A' 
+      && pSegment[iBegin+3]=='R' 
+    ){
+      QueryTerm *pTerm = &pQuery->pTerms[pQuery->nTerms-1];
+      if( (iBegin+6)<nSegment 
+       && pSegment[iBegin+4] == '/'
+       && pSegment[iBegin+5]>='0' && pSegment[iBegin+5]<='9'
+      ){
+        pTerm->nNear = (pSegment[iBegin+5] - '0');
+        nToken += 2;
+        if( pSegment[iBegin+6]>='0' && pSegment[iBegin+6]<=9 ){
+          pTerm->nNear = pTerm->nNear * 10 + (pSegment[iBegin+6] - '0');
+          iEnd++;
+        }
+        pModule->xNext(pCursor, &pToken, &nToken, &iBegin, &iEnd, &iPos);
+      } else {
+        pTerm->nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
+      }
+      pTerm->nNear++;
+      continue;
+    }
+
+    queryAdd(pQuery, pToken, nToken);
+    if( !inPhrase && iBegin>0 && pSegment[iBegin-1]=='-' ){
+      pQuery->pTerms[pQuery->nTerms-1].isNot = 1;
+    }
+    if( iEnd<nSegment && pSegment[iEnd]=='*' ){
+      pQuery->pTerms[pQuery->nTerms-1].isPrefix = 1;
+    }
+    pQuery->pTerms[pQuery->nTerms-1].iPhrase = nTerm;
+    if( inPhrase ){
+      nTerm++;
+    }
+  }
+
+  if( inPhrase && pQuery->nTerms>firstIndex ){
+    pQuery->pTerms[firstIndex].nPhrase = pQuery->nTerms - firstIndex - 1;
+  }
+
+  return pModule->xClose(pCursor);
+}
+
+/* Parse a query string, yielding a Query object pQuery.
+**
+** The calling function will need to queryClear() to clean up
+** the dynamically allocated memory held by pQuery.
+*/
+static int parseQuery(
+  fulltext_vtab *v,        /* The fulltext index */
+  const char *zInput,      /* Input text of the query string */
+  int nInput,              /* Size of the input text */
+  int dfltColumn,          /* Default column of the index to match against */
+  Query *pQuery            /* Write the parse results here. */
+){
+  int iInput, inPhrase = 0;
+  int ii;
+  QueryTerm *aTerm;
+
+  if( zInput==0 ) nInput = 0;
+  if( nInput<0 ) nInput = strlen(zInput);
+  pQuery->nTerms = 0;
+  pQuery->pTerms = NULL;
+  pQuery->nextIsOr = 0;
+  pQuery->nextColumn = dfltColumn;
+  pQuery->dfltColumn = dfltColumn;
+  pQuery->pFts = v;
+
+  for(iInput=0; iInput<nInput; ++iInput){
+    int i;
+    for(i=iInput; i<nInput && zInput[i]!='"'; ++i){}
+    if( i>iInput ){
+      tokenizeSegment(v->pTokenizer, zInput+iInput, i-iInput, inPhrase,
+                       pQuery);
+    }
+    iInput = i;
+    if( i<nInput ){
+      assert( zInput[i]=='"' );
+      inPhrase = !inPhrase;
+    }
+  }
+
+  if( inPhrase ){
+    /* unmatched quote */
+    queryClear(pQuery);
+    return SQLITE_ERROR;
+  }
+
+  /* Modify the values of the QueryTerm.nPhrase variables to account for
+  ** the NEAR operator. For the purposes of QueryTerm.nPhrase, phrases
+  ** and tokens connected by the NEAR operator are handled as a single
+  ** phrase. See comments above the QueryTerm structure for details.
+  */
+  aTerm = pQuery->pTerms;
+  for(ii=0; ii<pQuery->nTerms; ii++){
+    if( aTerm[ii].nNear || aTerm[ii].nPhrase ){
+      while (aTerm[ii+aTerm[ii].nPhrase].nNear) {
+        aTerm[ii].nPhrase += (1 + aTerm[ii+aTerm[ii].nPhrase+1].nPhrase);
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/* TODO(shess) Refactor the code to remove this forward decl. */
+static int flushPendingTerms(fulltext_vtab *v);
+
+/* Perform a full-text query using the search expression in
+** zInput[0..nInput-1].  Return a list of matching documents
+** in pResult.
+**
+** Queries must match column iColumn.  Or if iColumn>=nColumn
+** they are allowed to match against any column.
+*/
+static int fulltextQuery(
+  fulltext_vtab *v,      /* The full text index */
+  int iColumn,           /* Match against this column by default */
+  const char *zInput,    /* The query string */
+  int nInput,            /* Number of bytes in zInput[] */
+  DataBuffer *pResult,   /* Write the result doclist here */
+  Query *pQuery          /* Put parsed query string here */
+){
+  int i, iNext, rc;
+  DataBuffer left, right, or, new;
+  int nNot = 0;
+  QueryTerm *aTerm;
+
+  /* TODO(shess) Instead of flushing pendingTerms, we could query for
+  ** the relevant term and merge the doclist into what we receive from
+  ** the database.  Wait and see if this is a common issue, first.
+  **
+  ** A good reason not to flush is to not generate update-related
+  ** error codes from here.
+  */
+
+  /* Flush any buffered updates before executing the query. */
+  rc = flushPendingTerms(v);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* TODO(shess) I think that the queryClear() calls below are not
+  ** necessary, because fulltextClose() already clears the query.
+  */
+  rc = parseQuery(v, zInput, nInput, iColumn, pQuery);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Empty or NULL queries return no results. */
+  if( pQuery->nTerms==0 ){
+    dataBufferInit(pResult, 0);
+    return SQLITE_OK;
+  }
+
+  /* Merge AND terms. */
+  /* TODO(shess) I think we can early-exit if( i>nNot && left.nData==0 ). */
+  aTerm = pQuery->pTerms;
+  for(i = 0; i<pQuery->nTerms; i=iNext){
+    if( aTerm[i].isNot ){
+      /* Handle all NOT terms in a separate pass */
+      nNot++;
+      iNext = i + aTerm[i].nPhrase+1;
+      continue;
+    }
+    iNext = i + aTerm[i].nPhrase + 1;
+    rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &right);
+    if( rc ){
+      if( i!=nNot ) dataBufferDestroy(&left);
+      queryClear(pQuery);
+      return rc;
+    }
+    while( iNext<pQuery->nTerms && aTerm[iNext].isOr ){
+      rc = docListOfTerm(v, aTerm[iNext].iColumn, &aTerm[iNext], &or);
+      iNext += aTerm[iNext].nPhrase + 1;
+      if( rc ){
+        if( i!=nNot ) dataBufferDestroy(&left);
+        dataBufferDestroy(&right);
+        queryClear(pQuery);
+        return rc;
+      }
+      dataBufferInit(&new, 0);
+      docListOrMerge(right.pData, right.nData, or.pData, or.nData, &new);
+      dataBufferDestroy(&right);
+      dataBufferDestroy(&or);
+      right = new;
+    }
+    if( i==nNot ){           /* first term processed. */
+      left = right;
+    }else{
+      dataBufferInit(&new, 0);
+      docListAndMerge(left.pData, left.nData, right.pData, right.nData, &new);
+      dataBufferDestroy(&right);
+      dataBufferDestroy(&left);
+      left = new;
+    }
+  }
+
+  if( nNot==pQuery->nTerms ){
+    /* We do not yet know how to handle a query of only NOT terms */
+    return SQLITE_ERROR;
+  }
+
+  /* Do the EXCEPT terms */
+  for(i=0; i<pQuery->nTerms;  i += aTerm[i].nPhrase + 1){
+    if( !aTerm[i].isNot ) continue;
+    rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &right);
+    if( rc ){
+      queryClear(pQuery);
+      dataBufferDestroy(&left);
+      return rc;
+    }
+    dataBufferInit(&new, 0);
+    docListExceptMerge(left.pData, left.nData, right.pData, right.nData, &new);
+    dataBufferDestroy(&right);
+    dataBufferDestroy(&left);
+    left = new;
+  }
+
+  *pResult = left;
+  return rc;
+}
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+**
+** If idxNum==QUERY_GENERIC then do a full table scan against
+** the %_content table.
+**
+** If idxNum==QUERY_DOCID then do a docid lookup for a single entry
+** in the %_content table.
+**
+** If idxNum>=QUERY_FULLTEXT then use the full text index.  The
+** column on the left-hand side of the MATCH operator is column
+** number idxNum-QUERY_FULLTEXT, 0 indexed.  argv[0] is the right-hand
+** side of the MATCH operator.
+*/
+/* TODO(shess) Upgrade the cursor initialization and destruction to
+** account for fulltextFilter() being called multiple times on the
+** same cursor.  The current solution is very fragile.  Apply fix to
+** fts3 as appropriate.
+*/
+static int fulltextFilter(
+  sqlite3_vtab_cursor *pCursor,     /* The cursor used for this query */
+  int idxNum, const char *idxStr,   /* Which indexing scheme to use */
+  int argc, sqlite3_value **argv    /* Arguments for the indexing scheme */
+){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+  fulltext_vtab *v = cursor_vtab(c);
+  int rc;
+  StringBuffer sb;
+
+  FTSTRACE(("FTS3 Filter %p\n",pCursor));
+
+  initStringBuffer(&sb);
+  append(&sb, "SELECT docid, ");
+  appendList(&sb, v->nColumn, v->azContentColumn);
+  append(&sb, " FROM %_content");
+  if( idxNum!=QUERY_GENERIC ) append(&sb, " WHERE docid = ?");
+  sqlite3_finalize(c->pStmt);
+  rc = sql_prepare(v->db, v->zDb, v->zName, &c->pStmt, stringBufferData(&sb));
+  stringBufferDestroy(&sb);
+  if( rc!=SQLITE_OK ) return rc;
+
+  c->iCursorType = idxNum;
+  switch( idxNum ){
+    case QUERY_GENERIC:
+      break;
+
+    case QUERY_DOCID:
+      rc = sqlite3_bind_int64(c->pStmt, 1, sqlite3_value_int64(argv[0]));
+      if( rc!=SQLITE_OK ) return rc;
+      break;
+
+    default:   /* full-text search */
+    {
+      const char *zQuery = (const char *)sqlite3_value_text(argv[0]);
+      assert( idxNum<=QUERY_FULLTEXT+v->nColumn);
+      assert( argc==1 );
+      queryClear(&c->q);
+      if( c->result.nData!=0 ){
+        /* This case happens if the same cursor is used repeatedly. */
+        dlrDestroy(&c->reader);
+        dataBufferReset(&c->result);
+      }else{
+        dataBufferInit(&c->result, 0);
+      }
+      rc = fulltextQuery(v, idxNum-QUERY_FULLTEXT, zQuery, -1, &c->result, &c->q);
+      if( rc!=SQLITE_OK ) return rc;
+      if( c->result.nData!=0 ){
+        dlrInit(&c->reader, DL_DOCIDS, c->result.pData, c->result.nData);
+      }
+      break;
+    }
+  }
+
+  return fulltextNext(pCursor);
+}
+
+/* This is the xEof method of the virtual table.  The SQLite core
+** calls this routine to find out if it has reached the end of
+** a query's results set.
+*/
+static int fulltextEof(sqlite3_vtab_cursor *pCursor){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+  return c->eof;
+}
+
+/* This is the xColumn method of the virtual table.  The SQLite
+** core calls this method during a query when it needs the value
+** of a column from the virtual table.  This method needs to use
+** one of the sqlite3_result_*() routines to store the requested
+** value back in the pContext.
+*/
+static int fulltextColumn(sqlite3_vtab_cursor *pCursor,
+                          sqlite3_context *pContext, int idxCol){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+  fulltext_vtab *v = cursor_vtab(c);
+
+  if( idxCol<v->nColumn ){
+    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
+    sqlite3_result_value(pContext, pVal);
+  }else if( idxCol==v->nColumn ){
+    /* The extra column whose name is the same as the table.
+    ** Return a blob which is a pointer to the cursor
+    */
+    sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
+  }else if( idxCol==v->nColumn+1 ){
+    /* The docid column, which is an alias for rowid. */
+    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, 0);
+    sqlite3_result_value(pContext, pVal);
+  }
+  return SQLITE_OK;
+}
+
+/* This is the xRowid method.  The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set.  fts3
+** exposes %_content.docid as the rowid for the virtual table.  The
+** rowid should be written to *pRowid.
+*/
+static int fulltextRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  fulltext_cursor *c = (fulltext_cursor *) pCursor;
+
+  *pRowid = sqlite3_column_int64(c->pStmt, 0);
+  return SQLITE_OK;
+}
+
+/* Add all terms in [zText] to pendingTerms table.  If [iColumn] > 0,
+** we also store positions and offsets in the hash table using that
+** column number.
+*/
+static int buildTerms(fulltext_vtab *v, sqlite_int64 iDocid,
+                      const char *zText, int iColumn){
+  sqlite3_tokenizer *pTokenizer = v->pTokenizer;
+  sqlite3_tokenizer_cursor *pCursor;
+  const char *pToken;
+  int nTokenBytes;
+  int iStartOffset, iEndOffset, iPosition;
+  int rc;
+
+  rc = pTokenizer->pModule->xOpen(pTokenizer, zText, -1, &pCursor);
+  if( rc!=SQLITE_OK ) return rc;
+
+  pCursor->pTokenizer = pTokenizer;
+  while( SQLITE_OK==(rc=pTokenizer->pModule->xNext(pCursor,
+                                                   &pToken, &nTokenBytes,
+                                                   &iStartOffset, &iEndOffset,
+                                                   &iPosition)) ){
+    DLCollector *p;
+    int nData;                   /* Size of doclist before our update. */
+
+    /* Positions can't be negative; we use -1 as a terminator
+     * internally.  Token can't be NULL or empty. */
+    if( iPosition<0 || pToken == NULL || nTokenBytes == 0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    p = fts3HashFind(&v->pendingTerms, pToken, nTokenBytes);
+    if( p==NULL ){
+      nData = 0;
+      p = dlcNew(iDocid, DL_DEFAULT);
+      fts3HashInsert(&v->pendingTerms, pToken, nTokenBytes, p);
+
+      /* Overhead for our hash table entry, the key, and the value. */
+      v->nPendingData += sizeof(struct fts3HashElem)+sizeof(*p)+nTokenBytes;
+    }else{
+      nData = p->b.nData;
+      if( p->dlw.iPrevDocid!=iDocid ) dlcNext(p, iDocid);
+    }
+    if( iColumn>=0 ){
+      dlcAddPos(p, iColumn, iPosition, iStartOffset, iEndOffset);
+    }
+
+    /* Accumulate data added by dlcNew or dlcNext, and dlcAddPos. */
+    v->nPendingData += p->b.nData-nData;
+  }
+
+  /* TODO(shess) Check return?  Should this be able to cause errors at
+  ** this point?  Actually, same question about sqlite3_finalize(),
+  ** though one could argue that failure there means that the data is
+  ** not durable.  *ponder*
+  */
+  pTokenizer->pModule->xClose(pCursor);
+  if( SQLITE_DONE == rc ) return SQLITE_OK;
+  return rc;
+}
+
+/* Add doclists for all terms in [pValues] to pendingTerms table. */
+static int insertTerms(fulltext_vtab *v, sqlite_int64 iDocid,
+                       sqlite3_value **pValues){
+  int i;
+  for(i = 0; i < v->nColumn ; ++i){
+    char *zText = (char*)sqlite3_value_text(pValues[i]);
+    int rc = buildTerms(v, iDocid, zText, i);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  return SQLITE_OK;
+}
+
+/* Add empty doclists for all terms in the given row's content to
+** pendingTerms.
+*/
+static int deleteTerms(fulltext_vtab *v, sqlite_int64 iDocid){
+  const char **pValues;
+  int i, rc;
+
+  /* TODO(shess) Should we allow such tables at all? */
+  if( DL_DEFAULT==DL_DOCIDS ) return SQLITE_ERROR;
+
+  rc = content_select(v, iDocid, &pValues);
+  if( rc!=SQLITE_OK ) return rc;
+
+  for(i = 0 ; i < v->nColumn; ++i) {
+    rc = buildTerms(v, iDocid, pValues[i], -1);
+    if( rc!=SQLITE_OK ) break;
+  }
+
+  freeStringArray(v->nColumn, pValues);
+  return SQLITE_OK;
+}
+
+/* TODO(shess) Refactor the code to remove this forward decl. */
+static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid);
+
+/* Insert a row into the %_content table; set *piDocid to be the ID of the
+** new row.  Add doclists for terms to pendingTerms.
+*/
+static int index_insert(fulltext_vtab *v, sqlite3_value *pRequestDocid,
+                        sqlite3_value **pValues, sqlite_int64 *piDocid){
+  int rc;
+
+  rc = content_insert(v, pRequestDocid, pValues);  /* execute an SQL INSERT */
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* docid column is an alias for rowid. */
+  *piDocid = sqlite3_last_insert_rowid(v->db);
+  rc = initPendingTerms(v, *piDocid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return insertTerms(v, *piDocid, pValues);
+}
+
+/* Delete a row from the %_content table; add empty doclists for terms
+** to pendingTerms.
+*/
+static int index_delete(fulltext_vtab *v, sqlite_int64 iRow){
+  int rc = initPendingTerms(v, iRow);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = deleteTerms(v, iRow);
+  if( rc!=SQLITE_OK ) return rc;
+
+  return content_delete(v, iRow);  /* execute an SQL DELETE */
+}
+
+/* Update a row in the %_content table; add delete doclists to
+** pendingTerms for old terms not in the new data, add insert doclists
+** to pendingTerms for terms in the new data.
+*/
+static int index_update(fulltext_vtab *v, sqlite_int64 iRow,
+                        sqlite3_value **pValues){
+  int rc = initPendingTerms(v, iRow);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Generate an empty doclist for each term that previously appeared in this
+   * row. */
+  rc = deleteTerms(v, iRow);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = content_update(v, pValues, iRow);  /* execute an SQL UPDATE */
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Now add positions for terms which appear in the updated row. */
+  return insertTerms(v, iRow, pValues);
+}
+
+/*******************************************************************/
+/* InteriorWriter is used to collect terms and block references into
+** interior nodes in %_segments.  See commentary at top of file for
+** format.
+*/
+
+/* How large interior nodes can grow. */
+#define INTERIOR_MAX 2048
+
+/* Minimum number of terms per interior node (except the root). This
+** prevents large terms from making the tree too skinny - must be >0
+** so that the tree always makes progress.  Note that the min tree
+** fanout will be INTERIOR_MIN_TERMS+1.
+*/
+#define INTERIOR_MIN_TERMS 7
+#if INTERIOR_MIN_TERMS<1
+# error INTERIOR_MIN_TERMS must be greater than 0.
+#endif
+
+/* ROOT_MAX controls how much data is stored inline in the segment
+** directory.
+*/
+/* TODO(shess) Push ROOT_MAX down to whoever is writing things.  It's
+** only here so that interiorWriterRootInfo() and leafWriterRootInfo()
+** can both see it, but if the caller passed it in, we wouldn't even
+** need a define.
+*/
+#define ROOT_MAX 1024
+#if ROOT_MAX<VARINT_MAX*2
+# error ROOT_MAX must have enough space for a header.
+#endif
+
+/* InteriorBlock stores a linked-list of interior blocks while a lower
+** layer is being constructed.
+*/
+typedef struct InteriorBlock {
+  DataBuffer term;           /* Leftmost term in block's subtree. */
+  DataBuffer data;           /* Accumulated data for the block. */
+  struct InteriorBlock *next;
+} InteriorBlock;
+
+static InteriorBlock *interiorBlockNew(int iHeight, sqlite_int64 iChildBlock,
+                                       const char *pTerm, int nTerm){
+  InteriorBlock *block = sqlite3_malloc(sizeof(InteriorBlock));
+  char c[VARINT_MAX+VARINT_MAX];
+  int n;
+
+  if( block ){
+    memset(block, 0, sizeof(*block));
+    dataBufferInit(&block->term, 0);
+    dataBufferReplace(&block->term, pTerm, nTerm);
+
+    n = fts3PutVarint(c, iHeight);
+    n += fts3PutVarint(c+n, iChildBlock);
+    dataBufferInit(&block->data, INTERIOR_MAX);
+    dataBufferReplace(&block->data, c, n);
+  }
+  return block;
+}
+
+#ifndef NDEBUG
+/* Verify that the data is readable as an interior node. */
+static void interiorBlockValidate(InteriorBlock *pBlock){
+  const char *pData = pBlock->data.pData;
+  int nData = pBlock->data.nData;
+  int n, iDummy;
+  sqlite_int64 iBlockid;
+
+  assert( nData>0 );
+  assert( pData!=0 );
+  assert( pData+nData>pData );
+
+  /* Must lead with height of node as a varint(n), n>0 */
+  n = fts3GetVarint32(pData, &iDummy);
+  assert( n>0 );
+  assert( iDummy>0 );
+  assert( n<nData );
+  pData += n;
+  nData -= n;
+
+  /* Must contain iBlockid. */
+  n = fts3GetVarint(pData, &iBlockid);
+  assert( n>0 );
+  assert( n<=nData );
+  pData += n;
+  nData -= n;
+
+  /* Zero or more terms of positive length */
+  if( nData!=0 ){
+    /* First term is not delta-encoded. */
+    n = fts3GetVarint32(pData, &iDummy);
+    assert( n>0 );
+    assert( iDummy>0 );
+    assert( n+iDummy>0);
+    assert( n+iDummy<=nData );
+    pData += n+iDummy;
+    nData -= n+iDummy;
+
+    /* Following terms delta-encoded. */
+    while( nData!=0 ){
+      /* Length of shared prefix. */
+      n = fts3GetVarint32(pData, &iDummy);
+      assert( n>0 );
+      assert( iDummy>=0 );
+      assert( n<nData );
+      pData += n;
+      nData -= n;
+
+      /* Length and data of distinct suffix. */
+      n = fts3GetVarint32(pData, &iDummy);
+      assert( n>0 );
+      assert( iDummy>0 );
+      assert( n+iDummy>0);
+      assert( n+iDummy<=nData );
+      pData += n+iDummy;
+      nData -= n+iDummy;
+    }
+  }
+}
+#define ASSERT_VALID_INTERIOR_BLOCK(x) interiorBlockValidate(x)
+#else
+#define ASSERT_VALID_INTERIOR_BLOCK(x) assert( 1 )
+#endif
+
+typedef struct InteriorWriter {
+  int iHeight;                   /* from 0 at leaves. */
+  InteriorBlock *first, *last;
+  struct InteriorWriter *parentWriter;
+
+  DataBuffer term;               /* Last term written to block "last". */
+  sqlite_int64 iOpeningChildBlock; /* First child block in block "last". */
+#ifndef NDEBUG
+  sqlite_int64 iLastChildBlock;  /* for consistency checks. */
+#endif
+} InteriorWriter;
+
+/* Initialize an interior node where pTerm[nTerm] marks the leftmost
+** term in the tree.  iChildBlock is the leftmost child block at the
+** next level down the tree.
+*/
+static void interiorWriterInit(int iHeight, const char *pTerm, int nTerm,
+                               sqlite_int64 iChildBlock,
+                               InteriorWriter *pWriter){
+  InteriorBlock *block;
+  assert( iHeight>0 );
+  CLEAR(pWriter);
+
+  pWriter->iHeight = iHeight;
+  pWriter->iOpeningChildBlock = iChildBlock;
+#ifndef NDEBUG
+  pWriter->iLastChildBlock = iChildBlock;
+#endif
+  block = interiorBlockNew(iHeight, iChildBlock, pTerm, nTerm);
+  pWriter->last = pWriter->first = block;
+  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
+  dataBufferInit(&pWriter->term, 0);
+}
+
+/* Append the child node rooted at iChildBlock to the interior node,
+** with pTerm[nTerm] as the leftmost term in iChildBlock's subtree.
+*/
+static void interiorWriterAppend(InteriorWriter *pWriter,
+                                 const char *pTerm, int nTerm,
+                                 sqlite_int64 iChildBlock){
+  char c[VARINT_MAX+VARINT_MAX];
+  int n, nPrefix = 0;
+
+  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
+
+  /* The first term written into an interior node is actually
+  ** associated with the second child added (the first child was added
+  ** in interiorWriterInit, or in the if clause at the bottom of this
+  ** function).  That term gets encoded straight up, with nPrefix left
+  ** at 0.
+  */
+  if( pWriter->term.nData==0 ){
+    n = fts3PutVarint(c, nTerm);
+  }else{
+    while( nPrefix<pWriter->term.nData &&
+           pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
+      nPrefix++;
+    }
+
+    n = fts3PutVarint(c, nPrefix);
+    n += fts3PutVarint(c+n, nTerm-nPrefix);
+  }
+
+#ifndef NDEBUG
+  pWriter->iLastChildBlock++;
+#endif
+  assert( pWriter->iLastChildBlock==iChildBlock );
+
+  /* Overflow to a new block if the new term makes the current block
+  ** too big, and the current block already has enough terms.
+  */
+  if( pWriter->last->data.nData+n+nTerm-nPrefix>INTERIOR_MAX &&
+      iChildBlock-pWriter->iOpeningChildBlock>INTERIOR_MIN_TERMS ){
+    pWriter->last->next = interiorBlockNew(pWriter->iHeight, iChildBlock,
+                                           pTerm, nTerm);
+    pWriter->last = pWriter->last->next;
+    pWriter->iOpeningChildBlock = iChildBlock;
+    dataBufferReset(&pWriter->term);
+  }else{
+    dataBufferAppend2(&pWriter->last->data, c, n,
+                      pTerm+nPrefix, nTerm-nPrefix);
+    dataBufferReplace(&pWriter->term, pTerm, nTerm);
+  }
+  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
+}
+
+/* Free the space used by pWriter, including the linked-list of
+** InteriorBlocks, and parentWriter, if present.
+*/
+static int interiorWriterDestroy(InteriorWriter *pWriter){
+  InteriorBlock *block = pWriter->first;
+
+  while( block!=NULL ){
+    InteriorBlock *b = block;
+    block = block->next;
+    dataBufferDestroy(&b->term);
+    dataBufferDestroy(&b->data);
+    sqlite3_free(b);
+  }
+  if( pWriter->parentWriter!=NULL ){
+    interiorWriterDestroy(pWriter->parentWriter);
+    sqlite3_free(pWriter->parentWriter);
+  }
+  dataBufferDestroy(&pWriter->term);
+  SCRAMBLE(pWriter);
+  return SQLITE_OK;
+}
+
+/* If pWriter can fit entirely in ROOT_MAX, return it as the root info
+** directly, leaving *piEndBlockid unchanged.  Otherwise, flush
+** pWriter to %_segments, building a new layer of interior nodes, and
+** recursively ask for their root into.
+*/
+static int interiorWriterRootInfo(fulltext_vtab *v, InteriorWriter *pWriter,
+                                  char **ppRootInfo, int *pnRootInfo,
+                                  sqlite_int64 *piEndBlockid){
+  InteriorBlock *block = pWriter->first;
+  sqlite_int64 iBlockid = 0;
+  int rc;
+
+  /* If we can fit the segment inline */
+  if( block==pWriter->last && block->data.nData<ROOT_MAX ){
+    *ppRootInfo = block->data.pData;
+    *pnRootInfo = block->data.nData;
+    return SQLITE_OK;
+  }
+
+  /* Flush the first block to %_segments, and create a new level of
+  ** interior node.
+  */
+  ASSERT_VALID_INTERIOR_BLOCK(block);
+  rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+  *piEndBlockid = iBlockid;
+
+  pWriter->parentWriter = sqlite3_malloc(sizeof(*pWriter->parentWriter));
+  interiorWriterInit(pWriter->iHeight+1,
+                     block->term.pData, block->term.nData,
+                     iBlockid, pWriter->parentWriter);
+
+  /* Flush additional blocks and append to the higher interior
+  ** node.
+  */
+  for(block=block->next; block!=NULL; block=block->next){
+    ASSERT_VALID_INTERIOR_BLOCK(block);
+    rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
+    if( rc!=SQLITE_OK ) return rc;
+    *piEndBlockid = iBlockid;
+
+    interiorWriterAppend(pWriter->parentWriter,
+                         block->term.pData, block->term.nData, iBlockid);
+  }
+
+  /* Parent node gets the chance to be the root. */
+  return interiorWriterRootInfo(v, pWriter->parentWriter,
+                                ppRootInfo, pnRootInfo, piEndBlockid);
+}
+
+/****************************************************************/
+/* InteriorReader is used to read off the data from an interior node
+** (see comment at top of file for the format).
+*/
+typedef struct InteriorReader {
+  const char *pData;
+  int nData;
+
+  DataBuffer term;          /* previous term, for decoding term delta. */
+
+  sqlite_int64 iBlockid;
+} InteriorReader;
+
+static void interiorReaderDestroy(InteriorReader *pReader){
+  dataBufferDestroy(&pReader->term);
+  SCRAMBLE(pReader);
+}
+
+/* TODO(shess) The assertions are great, but what if we're in NDEBUG
+** and the blob is empty or otherwise contains suspect data?
+*/
+static void interiorReaderInit(const char *pData, int nData,
+                               InteriorReader *pReader){
+  int n, nTerm;
+
+  /* Require at least the leading flag byte */
+  assert( nData>0 );
+  assert( pData[0]!='\0' );
+
+  CLEAR(pReader);
+
+  /* Decode the base blockid, and set the cursor to the first term. */
+  n = fts3GetVarint(pData+1, &pReader->iBlockid);
+  assert( 1+n<=nData );
+  pReader->pData = pData+1+n;
+  pReader->nData = nData-(1+n);
+
+  /* A single-child interior node (such as when a leaf node was too
+  ** large for the segment directory) won't have any terms.
+  ** Otherwise, decode the first term.
+  */
+  if( pReader->nData==0 ){
+    dataBufferInit(&pReader->term, 0);
+  }else{
+    n = fts3GetVarint32(pReader->pData, &nTerm);
+    dataBufferInit(&pReader->term, nTerm);
+    dataBufferReplace(&pReader->term, pReader->pData+n, nTerm);
+    assert( n+nTerm<=pReader->nData );
+    pReader->pData += n+nTerm;
+    pReader->nData -= n+nTerm;
+  }
+}
+
+static int interiorReaderAtEnd(InteriorReader *pReader){
+  return pReader->term.nData==0;
+}
+
+static sqlite_int64 interiorReaderCurrentBlockid(InteriorReader *pReader){
+  return pReader->iBlockid;
+}
+
+static int interiorReaderTermBytes(InteriorReader *pReader){
+  assert( !interiorReaderAtEnd(pReader) );
+  return pReader->term.nData;
+}
+static const char *interiorReaderTerm(InteriorReader *pReader){
+  assert( !interiorReaderAtEnd(pReader) );
+  return pReader->term.pData;
+}
+
+/* Step forward to the next term in the node. */
+static void interiorReaderStep(InteriorReader *pReader){
+  assert( !interiorReaderAtEnd(pReader) );
+
+  /* If the last term has been read, signal eof, else construct the
+  ** next term.
+  */
+  if( pReader->nData==0 ){
+    dataBufferReset(&pReader->term);
+  }else{
+    int n, nPrefix, nSuffix;
+
+    n = fts3GetVarint32(pReader->pData, &nPrefix);
+    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
+
+    /* Truncate the current term and append suffix data. */
+    pReader->term.nData = nPrefix;
+    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
+
+    assert( n+nSuffix<=pReader->nData );
+    pReader->pData += n+nSuffix;
+    pReader->nData -= n+nSuffix;
+  }
+  pReader->iBlockid++;
+}
+
+/* Compare the current term to pTerm[nTerm], returning strcmp-style
+** results.  If isPrefix, equality means equal through nTerm bytes.
+*/
+static int interiorReaderTermCmp(InteriorReader *pReader,
+                                 const char *pTerm, int nTerm, int isPrefix){
+  const char *pReaderTerm = interiorReaderTerm(pReader);
+  int nReaderTerm = interiorReaderTermBytes(pReader);
+  int c, n = nReaderTerm<nTerm ? nReaderTerm : nTerm;
+
+  if( n==0 ){
+    if( nReaderTerm>0 ) return -1;
+    if( nTerm>0 ) return 1;
+    return 0;
+  }
+
+  c = memcmp(pReaderTerm, pTerm, n);
+  if( c!=0 ) return c;
+  if( isPrefix && n==nTerm ) return 0;
+  return nReaderTerm - nTerm;
+}
+
+/****************************************************************/
+/* LeafWriter is used to collect terms and associated doclist data
+** into leaf blocks in %_segments (see top of file for format info).
+** Expected usage is:
+**
+** LeafWriter writer;
+** leafWriterInit(0, 0, &writer);
+** while( sorted_terms_left_to_process ){
+**   // data is doclist data for that term.
+**   rc = leafWriterStep(v, &writer, pTerm, nTerm, pData, nData);
+**   if( rc!=SQLITE_OK ) goto err;
+** }
+** rc = leafWriterFinalize(v, &writer);
+**err:
+** leafWriterDestroy(&writer);
+** return rc;
+**
+** leafWriterStep() may write a collected leaf out to %_segments.
+** leafWriterFinalize() finishes writing any buffered data and stores
+** a root node in %_segdir.  leafWriterDestroy() frees all buffers and
+** InteriorWriters allocated as part of writing this segment.
+**
+** TODO(shess) Document leafWriterStepMerge().
+*/
+
+/* Put terms with data this big in their own block. */
+#define STANDALONE_MIN 1024
+
+/* Keep leaf blocks below this size. */
+#define LEAF_MAX 2048
+
+typedef struct LeafWriter {
+  int iLevel;
+  int idx;
+  sqlite_int64 iStartBlockid;     /* needed to create the root info */
+  sqlite_int64 iEndBlockid;       /* when we're done writing. */
+
+  DataBuffer term;                /* previous encoded term */
+  DataBuffer data;                /* encoding buffer */
+
+  /* bytes of first term in the current node which distinguishes that
+  ** term from the last term of the previous node.
+  */
+  int nTermDistinct;
+
+  InteriorWriter parentWriter;    /* if we overflow */
+  int has_parent;
+} LeafWriter;
+
+static void leafWriterInit(int iLevel, int idx, LeafWriter *pWriter){
+  CLEAR(pWriter);
+  pWriter->iLevel = iLevel;
+  pWriter->idx = idx;
+
+  dataBufferInit(&pWriter->term, 32);
+
+  /* Start out with a reasonably sized block, though it can grow. */
+  dataBufferInit(&pWriter->data, LEAF_MAX);
+}
+
+#ifndef NDEBUG
+/* Verify that the data is readable as a leaf node. */
+static void leafNodeValidate(const char *pData, int nData){
+  int n, iDummy;
+
+  if( nData==0 ) return;
+  assert( nData>0 );
+  assert( pData!=0 );
+  assert( pData+nData>pData );
+
+  /* Must lead with a varint(0) */
+  n = fts3GetVarint32(pData, &iDummy);
+  assert( iDummy==0 );
+  assert( n>0 );
+  assert( n<nData );
+  pData += n;
+  nData -= n;
+
+  /* Leading term length and data must fit in buffer. */
+  n = fts3GetVarint32(pData, &iDummy);
+  assert( n>0 );
+  assert( iDummy>0 );
+  assert( n+iDummy>0 );
+  assert( n+iDummy<nData );
+  pData += n+iDummy;
+  nData -= n+iDummy;
+
+  /* Leading term's doclist length and data must fit. */
+  n = fts3GetVarint32(pData, &iDummy);
+  assert( n>0 );
+  assert( iDummy>0 );
+  assert( n+iDummy>0 );
+  assert( n+iDummy<=nData );
+  ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
+  pData += n+iDummy;
+  nData -= n+iDummy;
+
+  /* Verify that trailing terms and doclists also are readable. */
+  while( nData!=0 ){
+    n = fts3GetVarint32(pData, &iDummy);
+    assert( n>0 );
+    assert( iDummy>=0 );
+    assert( n<nData );
+    pData += n;
+    nData -= n;
+    n = fts3GetVarint32(pData, &iDummy);
+    assert( n>0 );
+    assert( iDummy>0 );
+    assert( n+iDummy>0 );
+    assert( n+iDummy<nData );
+    pData += n+iDummy;
+    nData -= n+iDummy;
+
+    n = fts3GetVarint32(pData, &iDummy);
+    assert( n>0 );
+    assert( iDummy>0 );
+    assert( n+iDummy>0 );
+    assert( n+iDummy<=nData );
+    ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
+    pData += n+iDummy;
+    nData -= n+iDummy;
+  }
+}
+#define ASSERT_VALID_LEAF_NODE(p, n) leafNodeValidate(p, n)
+#else
+#define ASSERT_VALID_LEAF_NODE(p, n) assert( 1 )
+#endif
+
+/* Flush the current leaf node to %_segments, and adding the resulting
+** blockid and the starting term to the interior node which will
+** contain it.
+*/
+static int leafWriterInternalFlush(fulltext_vtab *v, LeafWriter *pWriter,
+                                   int iData, int nData){
+  sqlite_int64 iBlockid = 0;
+  const char *pStartingTerm;
+  int nStartingTerm, rc, n;
+
+  /* Must have the leading varint(0) flag, plus at least some
+  ** valid-looking data.
+  */
+  assert( nData>2 );
+  assert( iData>=0 );
+  assert( iData+nData<=pWriter->data.nData );
+  ASSERT_VALID_LEAF_NODE(pWriter->data.pData+iData, nData);
+
+  rc = block_insert(v, pWriter->data.pData+iData, nData, &iBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+  assert( iBlockid!=0 );
+
+  /* Reconstruct the first term in the leaf for purposes of building
+  ** the interior node.
+  */
+  n = fts3GetVarint32(pWriter->data.pData+iData+1, &nStartingTerm);
+  pStartingTerm = pWriter->data.pData+iData+1+n;
+  assert( pWriter->data.nData>iData+1+n+nStartingTerm );
+  assert( pWriter->nTermDistinct>0 );
+  assert( pWriter->nTermDistinct<=nStartingTerm );
+  nStartingTerm = pWriter->nTermDistinct;
+
+  if( pWriter->has_parent ){
+    interiorWriterAppend(&pWriter->parentWriter,
+                         pStartingTerm, nStartingTerm, iBlockid);
+  }else{
+    interiorWriterInit(1, pStartingTerm, nStartingTerm, iBlockid,
+                       &pWriter->parentWriter);
+    pWriter->has_parent = 1;
+  }
+
+  /* Track the span of this segment's leaf nodes. */
+  if( pWriter->iEndBlockid==0 ){
+    pWriter->iEndBlockid = pWriter->iStartBlockid = iBlockid;
+  }else{
+    pWriter->iEndBlockid++;
+    assert( iBlockid==pWriter->iEndBlockid );
+  }
+
+  return SQLITE_OK;
+}
+static int leafWriterFlush(fulltext_vtab *v, LeafWriter *pWriter){
+  int rc = leafWriterInternalFlush(v, pWriter, 0, pWriter->data.nData);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Re-initialize the output buffer. */
+  dataBufferReset(&pWriter->data);
+
+  return SQLITE_OK;
+}
+
+/* Fetch the root info for the segment.  If the entire leaf fits
+** within ROOT_MAX, then it will be returned directly, otherwise it
+** will be flushed and the root info will be returned from the
+** interior node.  *piEndBlockid is set to the blockid of the last
+** interior or leaf node written to disk (0 if none are written at
+** all).
+*/
+static int leafWriterRootInfo(fulltext_vtab *v, LeafWriter *pWriter,
+                              char **ppRootInfo, int *pnRootInfo,
+                              sqlite_int64 *piEndBlockid){
+  /* we can fit the segment entirely inline */
+  if( !pWriter->has_parent && pWriter->data.nData<ROOT_MAX ){
+    *ppRootInfo = pWriter->data.pData;
+    *pnRootInfo = pWriter->data.nData;
+    *piEndBlockid = 0;
+    return SQLITE_OK;
+  }
+
+  /* Flush remaining leaf data. */
+  if( pWriter->data.nData>0 ){
+    int rc = leafWriterFlush(v, pWriter);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* We must have flushed a leaf at some point. */
+  assert( pWriter->has_parent );
+
+  /* Tenatively set the end leaf blockid as the end blockid.  If the
+  ** interior node can be returned inline, this will be the final
+  ** blockid, otherwise it will be overwritten by
+  ** interiorWriterRootInfo().
+  */
+  *piEndBlockid = pWriter->iEndBlockid;
+
+  return interiorWriterRootInfo(v, &pWriter->parentWriter,
+                                ppRootInfo, pnRootInfo, piEndBlockid);
+}
+
+/* Collect the rootInfo data and store it into the segment directory.
+** This has the effect of flushing the segment's leaf data to
+** %_segments, and also flushing any interior nodes to %_segments.
+*/
+static int leafWriterFinalize(fulltext_vtab *v, LeafWriter *pWriter){
+  sqlite_int64 iEndBlockid;
+  char *pRootInfo;
+  int rc, nRootInfo;
+
+  rc = leafWriterRootInfo(v, pWriter, &pRootInfo, &nRootInfo, &iEndBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Don't bother storing an entirely empty segment. */
+  if( iEndBlockid==0 && nRootInfo==0 ) return SQLITE_OK;
+
+  return segdir_set(v, pWriter->iLevel, pWriter->idx,
+                    pWriter->iStartBlockid, pWriter->iEndBlockid,
+                    iEndBlockid, pRootInfo, nRootInfo);
+}
+
+static void leafWriterDestroy(LeafWriter *pWriter){
+  if( pWriter->has_parent ) interiorWriterDestroy(&pWriter->parentWriter);
+  dataBufferDestroy(&pWriter->term);
+  dataBufferDestroy(&pWriter->data);
+}
+
+/* Encode a term into the leafWriter, delta-encoding as appropriate.
+** Returns the length of the new term which distinguishes it from the
+** previous term, which can be used to set nTermDistinct when a node
+** boundary is crossed.
+*/
+static int leafWriterEncodeTerm(LeafWriter *pWriter,
+                                const char *pTerm, int nTerm){
+  char c[VARINT_MAX+VARINT_MAX];
+  int n, nPrefix = 0;
+
+  assert( nTerm>0 );
+  while( nPrefix<pWriter->term.nData &&
+         pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
+    nPrefix++;
+    /* Failing this implies that the terms weren't in order. */
+    assert( nPrefix<nTerm );
+  }
+
+  if( pWriter->data.nData==0 ){
+    /* Encode the node header and leading term as:
+    **  varint(0)
+    **  varint(nTerm)
+    **  char pTerm[nTerm]
+    */
+    n = fts3PutVarint(c, '\0');
+    n += fts3PutVarint(c+n, nTerm);
+    dataBufferAppend2(&pWriter->data, c, n, pTerm, nTerm);
+  }else{
+    /* Delta-encode the term as:
+    **  varint(nPrefix)
+    **  varint(nSuffix)
+    **  char pTermSuffix[nSuffix]
+    */
+    n = fts3PutVarint(c, nPrefix);
+    n += fts3PutVarint(c+n, nTerm-nPrefix);
+    dataBufferAppend2(&pWriter->data, c, n, pTerm+nPrefix, nTerm-nPrefix);
+  }
+  dataBufferReplace(&pWriter->term, pTerm, nTerm);
+
+  return nPrefix+1;
+}
+
+/* Used to avoid a memmove when a large amount of doclist data is in
+** the buffer.  This constructs a node and term header before
+** iDoclistData and flushes the resulting complete node using
+** leafWriterInternalFlush().
+*/
+static int leafWriterInlineFlush(fulltext_vtab *v, LeafWriter *pWriter,
+                                 const char *pTerm, int nTerm,
+                                 int iDoclistData){
+  char c[VARINT_MAX+VARINT_MAX];
+  int iData, n = fts3PutVarint(c, 0);
+  n += fts3PutVarint(c+n, nTerm);
+
+  /* There should always be room for the header.  Even if pTerm shared
+  ** a substantial prefix with the previous term, the entire prefix
+  ** could be constructed from earlier data in the doclist, so there
+  ** should be room.
+  */
+  assert( iDoclistData>=n+nTerm );
+
+  iData = iDoclistData-(n+nTerm);
+  memcpy(pWriter->data.pData+iData, c, n);
+  memcpy(pWriter->data.pData+iData+n, pTerm, nTerm);
+
+  return leafWriterInternalFlush(v, pWriter, iData, pWriter->data.nData-iData);
+}
+
+/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
+** %_segments.
+*/
+static int leafWriterStepMerge(fulltext_vtab *v, LeafWriter *pWriter,
+                               const char *pTerm, int nTerm,
+                               DLReader *pReaders, int nReaders){
+  char c[VARINT_MAX+VARINT_MAX];
+  int iTermData = pWriter->data.nData, iDoclistData;
+  int i, nData, n, nActualData, nActual, rc, nTermDistinct;
+
+  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
+  nTermDistinct = leafWriterEncodeTerm(pWriter, pTerm, nTerm);
+
+  /* Remember nTermDistinct if opening a new node. */
+  if( iTermData==0 ) pWriter->nTermDistinct = nTermDistinct;
+
+  iDoclistData = pWriter->data.nData;
+
+  /* Estimate the length of the merged doclist so we can leave space
+  ** to encode it.
+  */
+  for(i=0, nData=0; i<nReaders; i++){
+    nData += dlrAllDataBytes(&pReaders[i]);
+  }
+  n = fts3PutVarint(c, nData);
+  dataBufferAppend(&pWriter->data, c, n);
+
+  docListMerge(&pWriter->data, pReaders, nReaders);
+  ASSERT_VALID_DOCLIST(DL_DEFAULT,
+                       pWriter->data.pData+iDoclistData+n,
+                       pWriter->data.nData-iDoclistData-n, NULL);
+
+  /* The actual amount of doclist data at this point could be smaller
+  ** than the length we encoded.  Additionally, the space required to
+  ** encode this length could be smaller.  For small doclists, this is
+  ** not a big deal, we can just use memmove() to adjust things.
+  */
+  nActualData = pWriter->data.nData-(iDoclistData+n);
+  nActual = fts3PutVarint(c, nActualData);
+  assert( nActualData<=nData );
+  assert( nActual<=n );
+
+  /* If the new doclist is big enough for force a standalone leaf
+  ** node, we can immediately flush it inline without doing the
+  ** memmove().
+  */
+  /* TODO(shess) This test matches leafWriterStep(), which does this
+  ** test before it knows the cost to varint-encode the term and
+  ** doclist lengths.  At some point, change to
+  ** pWriter->data.nData-iTermData>STANDALONE_MIN.
+  */
+  if( nTerm+nActualData>STANDALONE_MIN ){
+    /* Push leaf node from before this term. */
+    if( iTermData>0 ){
+      rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
+      if( rc!=SQLITE_OK ) return rc;
+
+      pWriter->nTermDistinct = nTermDistinct;
+    }
+
+    /* Fix the encoded doclist length. */
+    iDoclistData += n - nActual;
+    memcpy(pWriter->data.pData+iDoclistData, c, nActual);
+
+    /* Push the standalone leaf node. */
+    rc = leafWriterInlineFlush(v, pWriter, pTerm, nTerm, iDoclistData);
+    if( rc!=SQLITE_OK ) return rc;
+
+    /* Leave the node empty. */
+    dataBufferReset(&pWriter->data);
+
+    return rc;
+  }
+
+  /* At this point, we know that the doclist was small, so do the
+  ** memmove if indicated.
+  */
+  if( nActual<n ){
+    memmove(pWriter->data.pData+iDoclistData+nActual,
+            pWriter->data.pData+iDoclistData+n,
+            pWriter->data.nData-(iDoclistData+n));
+    pWriter->data.nData -= n-nActual;
+  }
+
+  /* Replace written length with actual length. */
+  memcpy(pWriter->data.pData+iDoclistData, c, nActual);
+
+  /* If the node is too large, break things up. */
+  /* TODO(shess) This test matches leafWriterStep(), which does this
+  ** test before it knows the cost to varint-encode the term and
+  ** doclist lengths.  At some point, change to
+  ** pWriter->data.nData>LEAF_MAX.
+  */
+  if( iTermData+nTerm+nActualData>LEAF_MAX ){
+    /* Flush out the leading data as a node */
+    rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
+    if( rc!=SQLITE_OK ) return rc;
+
+    pWriter->nTermDistinct = nTermDistinct;
+
+    /* Rebuild header using the current term */
+    n = fts3PutVarint(pWriter->data.pData, 0);
+    n += fts3PutVarint(pWriter->data.pData+n, nTerm);
+    memcpy(pWriter->data.pData+n, pTerm, nTerm);
+    n += nTerm;
+
+    /* There should always be room, because the previous encoding
+    ** included all data necessary to construct the term.
+    */
+    assert( n<iDoclistData );
+    /* So long as STANDALONE_MIN is half or less of LEAF_MAX, the
+    ** following memcpy() is safe (as opposed to needing a memmove).
+    */
+    assert( 2*STANDALONE_MIN<=LEAF_MAX );
+    assert( n+pWriter->data.nData-iDoclistData<iDoclistData );
+    memcpy(pWriter->data.pData+n,
+           pWriter->data.pData+iDoclistData,
+           pWriter->data.nData-iDoclistData);
+    pWriter->data.nData -= iDoclistData-n;
+  }
+  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
+
+  return SQLITE_OK;
+}
+
+/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
+** %_segments.
+*/
+/* TODO(shess) Revise writeZeroSegment() so that doclists are
+** constructed directly in pWriter->data.
+*/
+static int leafWriterStep(fulltext_vtab *v, LeafWriter *pWriter,
+                          const char *pTerm, int nTerm,
+                          const char *pData, int nData){
+  int rc;
+  DLReader reader;
+
+  dlrInit(&reader, DL_DEFAULT, pData, nData);
+  rc = leafWriterStepMerge(v, pWriter, pTerm, nTerm, &reader, 1);
+  dlrDestroy(&reader);
+
+  return rc;
+}
+
+
+/****************************************************************/
+/* LeafReader is used to iterate over an individual leaf node. */
+typedef struct LeafReader {
+  DataBuffer term;          /* copy of current term. */
+
+  const char *pData;        /* data for current term. */
+  int nData;
+} LeafReader;
+
+static void leafReaderDestroy(LeafReader *pReader){
+  dataBufferDestroy(&pReader->term);
+  SCRAMBLE(pReader);
+}
+
+static int leafReaderAtEnd(LeafReader *pReader){
+  return pReader->nData<=0;
+}
+
+/* Access the current term. */
+static int leafReaderTermBytes(LeafReader *pReader){
+  return pReader->term.nData;
+}
+static const char *leafReaderTerm(LeafReader *pReader){
+  assert( pReader->term.nData>0 );
+  return pReader->term.pData;
+}
+
+/* Access the doclist data for the current term. */
+static int leafReaderDataBytes(LeafReader *pReader){
+  int nData;
+  assert( pReader->term.nData>0 );
+  fts3GetVarint32(pReader->pData, &nData);
+  return nData;
+}
+static const char *leafReaderData(LeafReader *pReader){
+  int n, nData;
+  assert( pReader->term.nData>0 );
+  n = fts3GetVarint32(pReader->pData, &nData);
+  return pReader->pData+n;
+}
+
+static void leafReaderInit(const char *pData, int nData,
+                           LeafReader *pReader){
+  int nTerm, n;
+
+  assert( nData>0 );
+  assert( pData[0]=='\0' );
+
+  CLEAR(pReader);
+
+  /* Read the first term, skipping the header byte. */
+  n = fts3GetVarint32(pData+1, &nTerm);
+  dataBufferInit(&pReader->term, nTerm);
+  dataBufferReplace(&pReader->term, pData+1+n, nTerm);
+
+  /* Position after the first term. */
+  assert( 1+n+nTerm<nData );
+  pReader->pData = pData+1+n+nTerm;
+  pReader->nData = nData-1-n-nTerm;
+}
+
+/* Step the reader forward to the next term. */
+static void leafReaderStep(LeafReader *pReader){
+  int n, nData, nPrefix, nSuffix;
+  assert( !leafReaderAtEnd(pReader) );
+
+  /* Skip previous entry's data block. */
+  n = fts3GetVarint32(pReader->pData, &nData);
+  assert( n+nData<=pReader->nData );
+  pReader->pData += n+nData;
+  pReader->nData -= n+nData;
+
+  if( !leafReaderAtEnd(pReader) ){
+    /* Construct the new term using a prefix from the old term plus a
+    ** suffix from the leaf data.
+    */
+    n = fts3GetVarint32(pReader->pData, &nPrefix);
+    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
+    assert( n+nSuffix<pReader->nData );
+    pReader->term.nData = nPrefix;
+    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
+
+    pReader->pData += n+nSuffix;
+    pReader->nData -= n+nSuffix;
+  }
+}
+
+/* strcmp-style comparison of pReader's current term against pTerm.
+** If isPrefix, equality means equal through nTerm bytes.
+*/
+static int leafReaderTermCmp(LeafReader *pReader,
+                             const char *pTerm, int nTerm, int isPrefix){
+  int c, n = pReader->term.nData<nTerm ? pReader->term.nData : nTerm;
+  if( n==0 ){
+    if( pReader->term.nData>0 ) return -1;
+    if(nTerm>0 ) return 1;
+    return 0;
+  }
+
+  c = memcmp(pReader->term.pData, pTerm, n);
+  if( c!=0 ) return c;
+  if( isPrefix && n==nTerm ) return 0;
+  return pReader->term.nData - nTerm;
+}
+
+
+/****************************************************************/
+/* LeavesReader wraps LeafReader to allow iterating over the entire
+** leaf layer of the tree.
+*/
+typedef struct LeavesReader {
+  int idx;                  /* Index within the segment. */
+
+  sqlite3_stmt *pStmt;      /* Statement we're streaming leaves from. */
+  int eof;                  /* we've seen SQLITE_DONE from pStmt. */
+
+  LeafReader leafReader;    /* reader for the current leaf. */
+  DataBuffer rootData;      /* root data for inline. */
+} LeavesReader;
+
+/* Access the current term. */
+static int leavesReaderTermBytes(LeavesReader *pReader){
+  assert( !pReader->eof );
+  return leafReaderTermBytes(&pReader->leafReader);
+}
+static const char *leavesReaderTerm(LeavesReader *pReader){
+  assert( !pReader->eof );
+  return leafReaderTerm(&pReader->leafReader);
+}
+
+/* Access the doclist data for the current term. */
+static int leavesReaderDataBytes(LeavesReader *pReader){
+  assert( !pReader->eof );
+  return leafReaderDataBytes(&pReader->leafReader);
+}
+static const char *leavesReaderData(LeavesReader *pReader){
+  assert( !pReader->eof );
+  return leafReaderData(&pReader->leafReader);
+}
+
+static int leavesReaderAtEnd(LeavesReader *pReader){
+  return pReader->eof;
+}
+
+/* loadSegmentLeaves() may not read all the way to SQLITE_DONE, thus
+** leaving the statement handle open, which locks the table.
+*/
+/* TODO(shess) This "solution" is not satisfactory.  Really, there
+** should be check-in function for all statement handles which
+** arranges to call sqlite3_reset().  This most likely will require
+** modification to control flow all over the place, though, so for now
+** just punt.
+**
+** Note the the current system assumes that segment merges will run to
+** completion, which is why this particular probably hasn't arisen in
+** this case.  Probably a brittle assumption.
+*/
+static int leavesReaderReset(LeavesReader *pReader){
+  return sqlite3_reset(pReader->pStmt);
+}
+
+static void leavesReaderDestroy(LeavesReader *pReader){
+  leafReaderDestroy(&pReader->leafReader);
+  dataBufferDestroy(&pReader->rootData);
+  SCRAMBLE(pReader);
+}
+
+/* Initialize pReader with the given root data (if iStartBlockid==0
+** the leaf data was entirely contained in the root), or from the
+** stream of blocks between iStartBlockid and iEndBlockid, inclusive.
+*/
+static int leavesReaderInit(fulltext_vtab *v,
+                            int idx,
+                            sqlite_int64 iStartBlockid,
+                            sqlite_int64 iEndBlockid,
+                            const char *pRootData, int nRootData,
+                            LeavesReader *pReader){
+  CLEAR(pReader);
+  pReader->idx = idx;
+
+  dataBufferInit(&pReader->rootData, 0);
+  if( iStartBlockid==0 ){
+    /* Entire leaf level fit in root data. */
+    dataBufferReplace(&pReader->rootData, pRootData, nRootData);
+    leafReaderInit(pReader->rootData.pData, pReader->rootData.nData,
+                   &pReader->leafReader);
+  }else{
+    sqlite3_stmt *s;
+    int rc = sql_get_leaf_statement(v, idx, &s);
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = sqlite3_bind_int64(s, 1, iStartBlockid);
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = sqlite3_bind_int64(s, 2, iEndBlockid);
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = sqlite3_step(s);
+    if( rc==SQLITE_DONE ){
+      pReader->eof = 1;
+      return SQLITE_OK;
+    }
+    if( rc!=SQLITE_ROW ) return rc;
+
+    pReader->pStmt = s;
+    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
+                   sqlite3_column_bytes(pReader->pStmt, 0),
+                   &pReader->leafReader);
+  }
+  return SQLITE_OK;
+}
+
+/* Step the current leaf forward to the next term.  If we reach the
+** end of the current leaf, step forward to the next leaf block.
+*/
+static int leavesReaderStep(fulltext_vtab *v, LeavesReader *pReader){
+  assert( !leavesReaderAtEnd(pReader) );
+  leafReaderStep(&pReader->leafReader);
+
+  if( leafReaderAtEnd(&pReader->leafReader) ){
+    int rc;
+    if( pReader->rootData.pData ){
+      pReader->eof = 1;
+      return SQLITE_OK;
+    }
+    rc = sqlite3_step(pReader->pStmt);
+    if( rc!=SQLITE_ROW ){
+      pReader->eof = 1;
+      return rc==SQLITE_DONE ? SQLITE_OK : rc;
+    }
+    leafReaderDestroy(&pReader->leafReader);
+    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
+                   sqlite3_column_bytes(pReader->pStmt, 0),
+                   &pReader->leafReader);
+  }
+  return SQLITE_OK;
+}
+
+/* Order LeavesReaders by their term, ignoring idx.  Readers at eof
+** always sort to the end.
+*/
+static int leavesReaderTermCmp(LeavesReader *lr1, LeavesReader *lr2){
+  if( leavesReaderAtEnd(lr1) ){
+    if( leavesReaderAtEnd(lr2) ) return 0;
+    return 1;
+  }
+  if( leavesReaderAtEnd(lr2) ) return -1;
+
+  return leafReaderTermCmp(&lr1->leafReader,
+                           leavesReaderTerm(lr2), leavesReaderTermBytes(lr2),
+                           0);
+}
+
+/* Similar to leavesReaderTermCmp(), with additional ordering by idx
+** so that older segments sort before newer segments.
+*/
+static int leavesReaderCmp(LeavesReader *lr1, LeavesReader *lr2){
+  int c = leavesReaderTermCmp(lr1, lr2);
+  if( c!=0 ) return c;
+  return lr1->idx-lr2->idx;
+}
+
+/* Assume that pLr[1]..pLr[nLr] are sorted.  Bubble pLr[0] into its
+** sorted position.
+*/
+static void leavesReaderReorder(LeavesReader *pLr, int nLr){
+  while( nLr>1 && leavesReaderCmp(pLr, pLr+1)>0 ){
+    LeavesReader tmp = pLr[0];
+    pLr[0] = pLr[1];
+    pLr[1] = tmp;
+    nLr--;
+    pLr++;
+  }
+}
+
+/* Initializes pReaders with the segments from level iLevel, returning
+** the number of segments in *piReaders.  Leaves pReaders in sorted
+** order.
+*/
+static int leavesReadersInit(fulltext_vtab *v, int iLevel,
+                             LeavesReader *pReaders, int *piReaders){
+  sqlite3_stmt *s;
+  int i, rc = sql_get_statement(v, SEGDIR_SELECT_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int(s, 1, iLevel);
+  if( rc!=SQLITE_OK ) return rc;
+
+  i = 0;
+  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
+    sqlite_int64 iStart = sqlite3_column_int64(s, 0);
+    sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
+    const char *pRootData = sqlite3_column_blob(s, 2);
+    int nRootData = sqlite3_column_bytes(s, 2);
+
+    assert( i<MERGE_COUNT );
+    rc = leavesReaderInit(v, i, iStart, iEnd, pRootData, nRootData,
+                          &pReaders[i]);
+    if( rc!=SQLITE_OK ) break;
+
+    i++;
+  }
+  if( rc!=SQLITE_DONE ){
+    while( i-->0 ){
+      leavesReaderDestroy(&pReaders[i]);
+    }
+    return rc;
+  }
+
+  *piReaders = i;
+
+  /* Leave our results sorted by term, then age. */
+  while( i-- ){
+    leavesReaderReorder(pReaders+i, *piReaders-i);
+  }
+  return SQLITE_OK;
+}
+
+/* Merge doclists from pReaders[nReaders] into a single doclist, which
+** is written to pWriter.  Assumes pReaders is ordered oldest to
+** newest.
+*/
+/* TODO(shess) Consider putting this inline in segmentMerge(). */
+static int leavesReadersMerge(fulltext_vtab *v,
+                              LeavesReader *pReaders, int nReaders,
+                              LeafWriter *pWriter){
+  DLReader dlReaders[MERGE_COUNT];
+  const char *pTerm = leavesReaderTerm(pReaders);
+  int i, nTerm = leavesReaderTermBytes(pReaders);
+
+  assert( nReaders<=MERGE_COUNT );
+
+  for(i=0; i<nReaders; i++){
+    dlrInit(&dlReaders[i], DL_DEFAULT,
+            leavesReaderData(pReaders+i),
+            leavesReaderDataBytes(pReaders+i));
+  }
+
+  return leafWriterStepMerge(v, pWriter, pTerm, nTerm, dlReaders, nReaders);
+}
+
+/* Forward ref due to mutual recursion with segdirNextIndex(). */
+static int segmentMerge(fulltext_vtab *v, int iLevel);
+
+/* Put the next available index at iLevel into *pidx.  If iLevel
+** already has MERGE_COUNT segments, they are merged to a higher
+** level to make room.
+*/
+static int segdirNextIndex(fulltext_vtab *v, int iLevel, int *pidx){
+  int rc = segdir_max_index(v, iLevel, pidx);
+  if( rc==SQLITE_DONE ){              /* No segments at iLevel. */
+    *pidx = 0;
+  }else if( rc==SQLITE_ROW ){
+    if( *pidx==(MERGE_COUNT-1) ){
+      rc = segmentMerge(v, iLevel);
+      if( rc!=SQLITE_OK ) return rc;
+      *pidx = 0;
+    }else{
+      (*pidx)++;
+    }
+  }else{
+    return rc;
+  }
+  return SQLITE_OK;
+}
+
+/* Merge MERGE_COUNT segments at iLevel into a new segment at
+** iLevel+1.  If iLevel+1 is already full of segments, those will be
+** merged to make room.
+*/
+static int segmentMerge(fulltext_vtab *v, int iLevel){
+  LeafWriter writer;
+  LeavesReader lrs[MERGE_COUNT];
+  int i, rc, idx = 0;
+
+  /* Determine the next available segment index at the next level,
+  ** merging as necessary.
+  */
+  rc = segdirNextIndex(v, iLevel+1, &idx);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* TODO(shess) This assumes that we'll always see exactly
+  ** MERGE_COUNT segments to merge at a given level.  That will be
+  ** broken if we allow the developer to request preemptive or
+  ** deferred merging.
+  */
+  memset(&lrs, '\0', sizeof(lrs));
+  rc = leavesReadersInit(v, iLevel, lrs, &i);
+  if( rc!=SQLITE_OK ) return rc;
+  assert( i==MERGE_COUNT );
+
+  leafWriterInit(iLevel+1, idx, &writer);
+
+  /* Since leavesReaderReorder() pushes readers at eof to the end,
+  ** when the first reader is empty, all will be empty.
+  */
+  while( !leavesReaderAtEnd(lrs) ){
+    /* Figure out how many readers share their next term. */
+    for(i=1; i<MERGE_COUNT && !leavesReaderAtEnd(lrs+i); i++){
+      if( 0!=leavesReaderTermCmp(lrs, lrs+i) ) break;
+    }
+
+    rc = leavesReadersMerge(v, lrs, i, &writer);
+    if( rc!=SQLITE_OK ) goto err;
+
+    /* Step forward those that were merged. */
+    while( i-->0 ){
+      rc = leavesReaderStep(v, lrs+i);
+      if( rc!=SQLITE_OK ) goto err;
+
+      /* Reorder by term, then by age. */
+      leavesReaderReorder(lrs+i, MERGE_COUNT-i);
+    }
+  }
+
+  for(i=0; i<MERGE_COUNT; i++){
+    leavesReaderDestroy(&lrs[i]);
+  }
+
+  rc = leafWriterFinalize(v, &writer);
+  leafWriterDestroy(&writer);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Delete the merged segment data. */
+  return segdir_delete(v, iLevel);
+
+ err:
+  for(i=0; i<MERGE_COUNT; i++){
+    leavesReaderDestroy(&lrs[i]);
+  }
+  leafWriterDestroy(&writer);
+  return rc;
+}
+
+/* Accumulate the union of *acc and *pData into *acc. */
+static void docListAccumulateUnion(DataBuffer *acc,
+                                   const char *pData, int nData) {
+  DataBuffer tmp = *acc;
+  dataBufferInit(acc, tmp.nData+nData);
+  docListUnion(tmp.pData, tmp.nData, pData, nData, acc);
+  dataBufferDestroy(&tmp);
+}
+
+/* TODO(shess) It might be interesting to explore different merge
+** strategies, here.  For instance, since this is a sorted merge, we
+** could easily merge many doclists in parallel.  With some
+** comprehension of the storage format, we could merge all of the
+** doclists within a leaf node directly from the leaf node's storage.
+** It may be worthwhile to merge smaller doclists before larger
+** doclists, since they can be traversed more quickly - but the
+** results may have less overlap, making them more expensive in a
+** different way.
+*/
+
+/* Scan pReader for pTerm/nTerm, and merge the term's doclist over
+** *out (any doclists with duplicate docids overwrite those in *out).
+** Internal function for loadSegmentLeaf().
+*/
+static int loadSegmentLeavesInt(fulltext_vtab *v, LeavesReader *pReader,
+                                const char *pTerm, int nTerm, int isPrefix,
+                                DataBuffer *out){
+  /* doclist data is accumulated into pBuffers similar to how one does
+  ** increment in binary arithmetic.  If index 0 is empty, the data is
+  ** stored there.  If there is data there, it is merged and the
+  ** results carried into position 1, with further merge-and-carry
+  ** until an empty position is found.
+  */
+  DataBuffer *pBuffers = NULL;
+  int nBuffers = 0, nMaxBuffers = 0, rc;
+
+  assert( nTerm>0 );
+
+  for(rc=SQLITE_OK; rc==SQLITE_OK && !leavesReaderAtEnd(pReader);
+      rc=leavesReaderStep(v, pReader)){
+    /* TODO(shess) Really want leavesReaderTermCmp(), but that name is
+    ** already taken to compare the terms of two LeavesReaders.  Think
+    ** on a better name.  [Meanwhile, break encapsulation rather than
+    ** use a confusing name.]
+    */
+    int c = leafReaderTermCmp(&pReader->leafReader, pTerm, nTerm, isPrefix);
+    if( c>0 ) break;      /* Past any possible matches. */
+    if( c==0 ){
+      const char *pData = leavesReaderData(pReader);
+      int iBuffer, nData = leavesReaderDataBytes(pReader);
+
+      /* Find the first empty buffer. */
+      for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
+        if( 0==pBuffers[iBuffer].nData ) break;
+      }
+
+      /* Out of buffers, add an empty one. */
+      if( iBuffer==nBuffers ){
+        if( nBuffers==nMaxBuffers ){
+          DataBuffer *p;
+          nMaxBuffers += 20;
+
+          /* Manual realloc so we can handle NULL appropriately. */
+          p = sqlite3_malloc(nMaxBuffers*sizeof(*pBuffers));
+          if( p==NULL ){
+            rc = SQLITE_NOMEM;
+            break;
+          }
+
+          if( nBuffers>0 ){
+            assert(pBuffers!=NULL);
+            memcpy(p, pBuffers, nBuffers*sizeof(*pBuffers));
+            sqlite3_free(pBuffers);
+          }
+          pBuffers = p;
+        }
+        dataBufferInit(&(pBuffers[nBuffers]), 0);
+        nBuffers++;
+      }
+
+      /* At this point, must have an empty at iBuffer. */
+      assert(iBuffer<nBuffers && pBuffers[iBuffer].nData==0);
+
+      /* If empty was first buffer, no need for merge logic. */
+      if( iBuffer==0 ){
+        dataBufferReplace(&(pBuffers[0]), pData, nData);
+      }else{
+        /* pAcc is the empty buffer the merged data will end up in. */
+        DataBuffer *pAcc = &(pBuffers[iBuffer]);
+        DataBuffer *p = &(pBuffers[0]);
+
+        /* Handle position 0 specially to avoid need to prime pAcc
+        ** with pData/nData.
+        */
+        dataBufferSwap(p, pAcc);
+        docListAccumulateUnion(pAcc, pData, nData);
+
+        /* Accumulate remaining doclists into pAcc. */
+        for(++p; p<pAcc; ++p){
+          docListAccumulateUnion(pAcc, p->pData, p->nData);
+
+          /* dataBufferReset() could allow a large doclist to blow up
+          ** our memory requirements.
+          */
+          if( p->nCapacity<1024 ){
+            dataBufferReset(p);
+          }else{
+            dataBufferDestroy(p);
+            dataBufferInit(p, 0);
+          }
+        }
+      }
+    }
+  }
+
+  /* Union all the doclists together into *out. */
+  /* TODO(shess) What if *out is big?  Sigh. */
+  if( rc==SQLITE_OK && nBuffers>0 ){
+    int iBuffer;
+    for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
+      if( pBuffers[iBuffer].nData>0 ){
+        if( out->nData==0 ){
+          dataBufferSwap(out, &(pBuffers[iBuffer]));
+        }else{
+          docListAccumulateUnion(out, pBuffers[iBuffer].pData,
+                                 pBuffers[iBuffer].nData);
+        }
+      }
+    }
+  }
+
+  while( nBuffers-- ){
+    dataBufferDestroy(&(pBuffers[nBuffers]));
+  }
+  if( pBuffers!=NULL ) sqlite3_free(pBuffers);
+
+  return rc;
+}
+
+/* Call loadSegmentLeavesInt() with pData/nData as input. */
+static int loadSegmentLeaf(fulltext_vtab *v, const char *pData, int nData,
+                           const char *pTerm, int nTerm, int isPrefix,
+                           DataBuffer *out){
+  LeavesReader reader;
+  int rc;
+
+  assert( nData>1 );
+  assert( *pData=='\0' );
+  rc = leavesReaderInit(v, 0, 0, 0, pData, nData, &reader);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
+  leavesReaderReset(&reader);
+  leavesReaderDestroy(&reader);
+  return rc;
+}
+
+/* Call loadSegmentLeavesInt() with the leaf nodes from iStartLeaf to
+** iEndLeaf (inclusive) as input, and merge the resulting doclist into
+** out.
+*/
+static int loadSegmentLeaves(fulltext_vtab *v,
+                             sqlite_int64 iStartLeaf, sqlite_int64 iEndLeaf,
+                             const char *pTerm, int nTerm, int isPrefix,
+                             DataBuffer *out){
+  int rc;
+  LeavesReader reader;
+
+  assert( iStartLeaf<=iEndLeaf );
+  rc = leavesReaderInit(v, 0, iStartLeaf, iEndLeaf, NULL, 0, &reader);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
+  leavesReaderReset(&reader);
+  leavesReaderDestroy(&reader);
+  return rc;
+}
+
+/* Taking pData/nData as an interior node, find the sequence of child
+** nodes which could include pTerm/nTerm/isPrefix.  Note that the
+** interior node terms logically come between the blocks, so there is
+** one more blockid than there are terms (that block contains terms >=
+** the last interior-node term).
+*/
+/* TODO(shess) The calling code may already know that the end child is
+** not worth calculating, because the end may be in a later sibling
+** node.  Consider whether breaking symmetry is worthwhile.  I suspect
+** it is not worthwhile.
+*/
+static void getChildrenContaining(const char *pData, int nData,
+                                  const char *pTerm, int nTerm, int isPrefix,
+                                  sqlite_int64 *piStartChild,
+                                  sqlite_int64 *piEndChild){
+  InteriorReader reader;
+
+  assert( nData>1 );
+  assert( *pData!='\0' );
+  interiorReaderInit(pData, nData, &reader);
+
+  /* Scan for the first child which could contain pTerm/nTerm. */
+  while( !interiorReaderAtEnd(&reader) ){
+    if( interiorReaderTermCmp(&reader, pTerm, nTerm, 0)>0 ) break;
+    interiorReaderStep(&reader);
+  }
+  *piStartChild = interiorReaderCurrentBlockid(&reader);
+
+  /* Keep scanning to find a term greater than our term, using prefix
+  ** comparison if indicated.  If isPrefix is false, this will be the
+  ** same blockid as the starting block.
+  */
+  while( !interiorReaderAtEnd(&reader) ){
+    if( interiorReaderTermCmp(&reader, pTerm, nTerm, isPrefix)>0 ) break;
+    interiorReaderStep(&reader);
+  }
+  *piEndChild = interiorReaderCurrentBlockid(&reader);
+
+  interiorReaderDestroy(&reader);
+
+  /* Children must ascend, and if !prefix, both must be the same. */
+  assert( *piEndChild>=*piStartChild );
+  assert( isPrefix || *piStartChild==*piEndChild );
+}
+
+/* Read block at iBlockid and pass it with other params to
+** getChildrenContaining().
+*/
+static int loadAndGetChildrenContaining(
+  fulltext_vtab *v,
+  sqlite_int64 iBlockid,
+  const char *pTerm, int nTerm, int isPrefix,
+  sqlite_int64 *piStartChild, sqlite_int64 *piEndChild
+){
+  sqlite3_stmt *s = NULL;
+  int rc;
+
+  assert( iBlockid!=0 );
+  assert( pTerm!=NULL );
+  assert( nTerm!=0 );        /* TODO(shess) Why not allow this? */
+  assert( piStartChild!=NULL );
+  assert( piEndChild!=NULL );
+
+  rc = sql_get_statement(v, BLOCK_SELECT_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_bind_int64(s, 1, iBlockid);
+  if( rc!=SQLITE_OK ) return rc;
+
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_DONE ) return SQLITE_ERROR;
+  if( rc!=SQLITE_ROW ) return rc;
+
+  getChildrenContaining(sqlite3_column_blob(s, 0), sqlite3_column_bytes(s, 0),
+                        pTerm, nTerm, isPrefix, piStartChild, piEndChild);
+
+  /* We expect only one row.  We must execute another sqlite3_step()
+   * to complete the iteration; otherwise the table will remain
+   * locked. */
+  rc = sqlite3_step(s);
+  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
+  if( rc!=SQLITE_DONE ) return rc;
+
+  return SQLITE_OK;
+}
+
+/* Traverse the tree represented by pData[nData] looking for
+** pTerm[nTerm], placing its doclist into *out.  This is internal to
+** loadSegment() to make error-handling cleaner.
+*/
+static int loadSegmentInt(fulltext_vtab *v, const char *pData, int nData,
+                          sqlite_int64 iLeavesEnd,
+                          const char *pTerm, int nTerm, int isPrefix,
+                          DataBuffer *out){
+  /* Special case where root is a leaf. */
+  if( *pData=='\0' ){
+    return loadSegmentLeaf(v, pData, nData, pTerm, nTerm, isPrefix, out);
+  }else{
+    int rc;
+    sqlite_int64 iStartChild, iEndChild;
+
+    /* Process pData as an interior node, then loop down the tree
+    ** until we find the set of leaf nodes to scan for the term.
+    */
+    getChildrenContaining(pData, nData, pTerm, nTerm, isPrefix,
+                          &iStartChild, &iEndChild);
+    while( iStartChild>iLeavesEnd ){
+      sqlite_int64 iNextStart, iNextEnd;
+      rc = loadAndGetChildrenContaining(v, iStartChild, pTerm, nTerm, isPrefix,
+                                        &iNextStart, &iNextEnd);
+      if( rc!=SQLITE_OK ) return rc;
+
+      /* If we've branched, follow the end branch, too. */
+      if( iStartChild!=iEndChild ){
+        sqlite_int64 iDummy;
+        rc = loadAndGetChildrenContaining(v, iEndChild, pTerm, nTerm, isPrefix,
+                                          &iDummy, &iNextEnd);
+        if( rc!=SQLITE_OK ) return rc;
+      }
+
+      assert( iNextStart<=iNextEnd );
+      iStartChild = iNextStart;
+      iEndChild = iNextEnd;
+    }
+    assert( iStartChild<=iLeavesEnd );
+    assert( iEndChild<=iLeavesEnd );
+
+    /* Scan through the leaf segments for doclists. */
+    return loadSegmentLeaves(v, iStartChild, iEndChild,
+                             pTerm, nTerm, isPrefix, out);
+  }
+}
+
+/* Call loadSegmentInt() to collect the doclist for pTerm/nTerm, then
+** merge its doclist over *out (any duplicate doclists read from the
+** segment rooted at pData will overwrite those in *out).
+*/
+/* TODO(shess) Consider changing this to determine the depth of the
+** leaves using either the first characters of interior nodes (when
+** ==1, we're one level above the leaves), or the first character of
+** the root (which will describe the height of the tree directly).
+** Either feels somewhat tricky to me.
+*/
+/* TODO(shess) The current merge is likely to be slow for large
+** doclists (though it should process from newest/smallest to
+** oldest/largest, so it may not be that bad).  It might be useful to
+** modify things to allow for N-way merging.  This could either be
+** within a segment, with pairwise merges across segments, or across
+** all segments at once.
+*/
+static int loadSegment(fulltext_vtab *v, const char *pData, int nData,
+                       sqlite_int64 iLeavesEnd,
+                       const char *pTerm, int nTerm, int isPrefix,
+                       DataBuffer *out){
+  DataBuffer result;
+  int rc;
+
+  assert( nData>1 );
+
+  /* This code should never be called with buffered updates. */
+  assert( v->nPendingData<0 );
+
+  dataBufferInit(&result, 0);
+  rc = loadSegmentInt(v, pData, nData, iLeavesEnd,
+                      pTerm, nTerm, isPrefix, &result);
+  if( rc==SQLITE_OK && result.nData>0 ){
+    if( out->nData==0 ){
+      DataBuffer tmp = *out;
+      *out = result;
+      result = tmp;
+    }else{
+      DataBuffer merged;
+      DLReader readers[2];
+
+      dlrInit(&readers[0], DL_DEFAULT, out->pData, out->nData);
+      dlrInit(&readers[1], DL_DEFAULT, result.pData, result.nData);
+      dataBufferInit(&merged, out->nData+result.nData);
+      docListMerge(&merged, readers, 2);
+      dataBufferDestroy(out);
+      *out = merged;
+      dlrDestroy(&readers[0]);
+      dlrDestroy(&readers[1]);
+    }
+  }
+  dataBufferDestroy(&result);
+  return rc;
+}
+
+/* Scan the database and merge together the posting lists for the term
+** into *out.
+*/
+static int termSelect(fulltext_vtab *v, int iColumn,
+                      const char *pTerm, int nTerm, int isPrefix,
+                      DocListType iType, DataBuffer *out){
+  DataBuffer doclist;
+  sqlite3_stmt *s;
+  int rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* This code should never be called with buffered updates. */
+  assert( v->nPendingData<0 );
+
+  dataBufferInit(&doclist, 0);
+
+  /* Traverse the segments from oldest to newest so that newer doclist
+  ** elements for given docids overwrite older elements.
+  */
+  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
+    const char *pData = sqlite3_column_blob(s, 0);
+    const int nData = sqlite3_column_bytes(s, 0);
+    const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
+    rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, isPrefix,
+                     &doclist);
+    if( rc!=SQLITE_OK ) goto err;
+  }
+  if( rc==SQLITE_DONE ){
+    if( doclist.nData!=0 ){
+      /* TODO(shess) The old term_select_all() code applied the column
+      ** restrict as we merged segments, leading to smaller buffers.
+      ** This is probably worthwhile to bring back, once the new storage
+      ** system is checked in.
+      */
+      if( iColumn==v->nColumn) iColumn = -1;
+      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
+                  iColumn, iType, out);
+    }
+    rc = SQLITE_OK;
+  }
+
+ err:
+  dataBufferDestroy(&doclist);
+  return rc;
+}
+
+/****************************************************************/
+/* Used to hold hashtable data for sorting. */
+typedef struct TermData {
+  const char *pTerm;
+  int nTerm;
+  DLCollector *pCollector;
+} TermData;
+
+/* Orders TermData elements in strcmp fashion ( <0 for less-than, 0
+** for equal, >0 for greater-than).
+*/
+static int termDataCmp(const void *av, const void *bv){
+  const TermData *a = (const TermData *)av;
+  const TermData *b = (const TermData *)bv;
+  int n = a->nTerm<b->nTerm ? a->nTerm : b->nTerm;
+  int c = memcmp(a->pTerm, b->pTerm, n);
+  if( c!=0 ) return c;
+  return a->nTerm-b->nTerm;
+}
+
+/* Order pTerms data by term, then write a new level 0 segment using
+** LeafWriter.
+*/
+static int writeZeroSegment(fulltext_vtab *v, fts3Hash *pTerms){
+  fts3HashElem *e;
+  int idx, rc, i, n;
+  TermData *pData;
+  LeafWriter writer;
+  DataBuffer dl;
+
+  /* Determine the next index at level 0, merging as necessary. */
+  rc = segdirNextIndex(v, 0, &idx);
+  if( rc!=SQLITE_OK ) return rc;
+
+  n = fts3HashCount(pTerms);
+  pData = sqlite3_malloc(n*sizeof(TermData));
+
+  for(i = 0, e = fts3HashFirst(pTerms); e; i++, e = fts3HashNext(e)){
+    assert( i<n );
+    pData[i].pTerm = fts3HashKey(e);
+    pData[i].nTerm = fts3HashKeysize(e);
+    pData[i].pCollector = fts3HashData(e);
+  }
+  assert( i==n );
+
+  /* TODO(shess) Should we allow user-defined collation sequences,
+  ** here?  I think we only need that once we support prefix searches.
+  */
+  if( n>1 ) qsort(pData, n, sizeof(*pData), termDataCmp);
+
+  /* TODO(shess) Refactor so that we can write directly to the segment
+  ** DataBuffer, as happens for segment merges.
+  */
+  leafWriterInit(0, idx, &writer);
+  dataBufferInit(&dl, 0);
+  for(i=0; i<n; i++){
+    dataBufferReset(&dl);
+    dlcAddDoclist(pData[i].pCollector, &dl);
+    rc = leafWriterStep(v, &writer,
+                        pData[i].pTerm, pData[i].nTerm, dl.pData, dl.nData);
+    if( rc!=SQLITE_OK ) goto err;
+  }
+  rc = leafWriterFinalize(v, &writer);
+
+ err:
+  dataBufferDestroy(&dl);
+  sqlite3_free(pData);
+  leafWriterDestroy(&writer);
+  return rc;
+}
+
+/* If pendingTerms has data, free it. */
+static int clearPendingTerms(fulltext_vtab *v){
+  if( v->nPendingData>=0 ){
+    fts3HashElem *e;
+    for(e=fts3HashFirst(&v->pendingTerms); e; e=fts3HashNext(e)){
+      dlcDelete(fts3HashData(e));
+    }
+    fts3HashClear(&v->pendingTerms);
+    v->nPendingData = -1;
+  }
+  return SQLITE_OK;
+}
+
+/* If pendingTerms has data, flush it to a level-zero segment, and
+** free it.
+*/
+static int flushPendingTerms(fulltext_vtab *v){
+  if( v->nPendingData>=0 ){
+    int rc = writeZeroSegment(v, &v->pendingTerms);
+    if( rc==SQLITE_OK ) clearPendingTerms(v);
+    return rc;
+  }
+  return SQLITE_OK;
+}
+
+/* If pendingTerms is "too big", or docid is out of order, flush it.
+** Regardless, be certain that pendingTerms is initialized for use.
+*/
+static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid){
+  /* TODO(shess) Explore whether partially flushing the buffer on
+  ** forced-flush would provide better performance.  I suspect that if
+  ** we ordered the doclists by size and flushed the largest until the
+  ** buffer was half empty, that would let the less frequent terms
+  ** generate longer doclists.
+  */
+  if( iDocid<=v->iPrevDocid || v->nPendingData>kPendingThreshold ){
+    int rc = flushPendingTerms(v);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  if( v->nPendingData<0 ){
+    fts3HashInit(&v->pendingTerms, FTS3_HASH_STRING, 1);
+    v->nPendingData = 0;
+  }
+  v->iPrevDocid = iDocid;
+  return SQLITE_OK;
+}
+
+/* This function implements the xUpdate callback; it is the top-level entry
+ * point for inserting, deleting or updating a row in a full-text table. */
+static int fulltextUpdate(sqlite3_vtab *pVtab, int nArg, sqlite3_value **ppArg,
+                          sqlite_int64 *pRowid){
+  fulltext_vtab *v = (fulltext_vtab *) pVtab;
+  int rc;
+
+  FTSTRACE(("FTS3 Update %p\n", pVtab));
+
+  if( nArg<2 ){
+    rc = index_delete(v, sqlite3_value_int64(ppArg[0]));
+  } else if( sqlite3_value_type(ppArg[0]) != SQLITE_NULL ){
+    /* An update:
+     * ppArg[0] = old rowid
+     * ppArg[1] = new rowid
+     * ppArg[2..2+v->nColumn-1] = values
+     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
+     * ppArg[2+v->nColumn+1] = value for docid
+     */
+    sqlite_int64 rowid = sqlite3_value_int64(ppArg[0]);
+    if( sqlite3_value_type(ppArg[1]) != SQLITE_INTEGER ||
+        sqlite3_value_int64(ppArg[1]) != rowid ){
+      rc = SQLITE_ERROR;  /* we don't allow changing the rowid */
+    }else if( sqlite3_value_type(ppArg[2+v->nColumn+1]) != SQLITE_INTEGER ||
+              sqlite3_value_int64(ppArg[2+v->nColumn+1]) != rowid ){
+      rc = SQLITE_ERROR;  /* we don't allow changing the docid */
+    }else{
+      assert( nArg==2+v->nColumn+2);
+      rc = index_update(v, rowid, &ppArg[2]);
+    }
+  } else {
+    /* An insert:
+     * ppArg[1] = requested rowid
+     * ppArg[2..2+v->nColumn-1] = values
+     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
+     * ppArg[2+v->nColumn+1] = value for docid
+     */
+    sqlite3_value *pRequestDocid = ppArg[2+v->nColumn+1];
+    assert( nArg==2+v->nColumn+2);
+    if( SQLITE_NULL != sqlite3_value_type(pRequestDocid) &&
+        SQLITE_NULL != sqlite3_value_type(ppArg[1]) ){
+      /* TODO(shess) Consider allowing this to work if the values are
+      ** identical.  I'm inclined to discourage that usage, though,
+      ** given that both rowid and docid are special columns.  Better
+      ** would be to define one or the other as the default winner,
+      ** but should it be fts3-centric (docid) or SQLite-centric
+      ** (rowid)?
+      */
+      rc = SQLITE_ERROR;
+    }else{
+      if( SQLITE_NULL == sqlite3_value_type(pRequestDocid) ){
+        pRequestDocid = ppArg[1];
+      }
+      rc = index_insert(v, pRequestDocid, &ppArg[2], pRowid);
+    }
+  }
+
+  return rc;
+}
+
+static int fulltextSync(sqlite3_vtab *pVtab){
+  FTSTRACE(("FTS3 xSync()\n"));
+  return flushPendingTerms((fulltext_vtab *)pVtab);
+}
+
+static int fulltextBegin(sqlite3_vtab *pVtab){
+  fulltext_vtab *v = (fulltext_vtab *) pVtab;
+  FTSTRACE(("FTS3 xBegin()\n"));
+
+  /* Any buffered updates should have been cleared by the previous
+  ** transaction.
+  */
+  assert( v->nPendingData<0 );
+  return clearPendingTerms(v);
+}
+
+static int fulltextCommit(sqlite3_vtab *pVtab){
+  fulltext_vtab *v = (fulltext_vtab *) pVtab;
+  FTSTRACE(("FTS3 xCommit()\n"));
+
+  /* Buffered updates should have been cleared by fulltextSync(). */
+  assert( v->nPendingData<0 );
+  return clearPendingTerms(v);
+}
+
+static int fulltextRollback(sqlite3_vtab *pVtab){
+  FTSTRACE(("FTS3 xRollback()\n"));
+  return clearPendingTerms((fulltext_vtab *)pVtab);
+}
+
+/*
+** Implementation of the snippet() function for FTS3
+*/
+static void snippetFunc(
+  sqlite3_context *pContext,
+  int argc,
+  sqlite3_value **argv
+){
+  fulltext_cursor *pCursor;
+  if( argc<1 ) return;
+  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
+      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
+    sqlite3_result_error(pContext, "illegal first argument to html_snippet",-1);
+  }else{
+    const char *zStart = "<b>";
+    const char *zEnd = "</b>";
+    const char *zEllipsis = "<b>...</b>";
+    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
+    if( argc>=2 ){
+      zStart = (const char*)sqlite3_value_text(argv[1]);
+      if( argc>=3 ){
+        zEnd = (const char*)sqlite3_value_text(argv[2]);
+        if( argc>=4 ){
+          zEllipsis = (const char*)sqlite3_value_text(argv[3]);
+        }
+      }
+    }
+    snippetAllOffsets(pCursor);
+    snippetText(pCursor, zStart, zEnd, zEllipsis);
+    sqlite3_result_text(pContext, pCursor->snippet.zSnippet,
+                        pCursor->snippet.nSnippet, SQLITE_STATIC);
+  }
+}
+
+/*
+** Implementation of the offsets() function for FTS3
+*/
+static void snippetOffsetsFunc(
+  sqlite3_context *pContext,
+  int argc,
+  sqlite3_value **argv
+){
+  fulltext_cursor *pCursor;
+  if( argc<1 ) return;
+  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
+      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
+    sqlite3_result_error(pContext, "illegal first argument to offsets",-1);
+  }else{
+    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
+    snippetAllOffsets(pCursor);
+    snippetOffsetText(&pCursor->snippet);
+    sqlite3_result_text(pContext,
+                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
+                        SQLITE_STATIC);
+  }
+}
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fulltextFindFunction(
+  sqlite3_vtab *pVtab,
+  int nArg,
+  const char *zName,
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+  void **ppArg
+){
+  if( strcmp(zName,"snippet")==0 ){
+    *pxFunc = snippetFunc;
+    return 1;
+  }else if( strcmp(zName,"offsets")==0 ){
+    *pxFunc = snippetOffsetsFunc;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Rename an fts3 table.
+*/
+static int fulltextRename(
+  sqlite3_vtab *pVtab,
+  const char *zName
+){
+  fulltext_vtab *p = (fulltext_vtab *)pVtab;
+  int rc = SQLITE_NOMEM;
+  char *zSql = sqlite3_mprintf(
+    "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';"
+    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';"
+    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';"
+    , p->zDb, p->zName, zName 
+    , p->zDb, p->zName, zName 
+    , p->zDb, p->zName, zName
+  );
+  if( zSql ){
+    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+static const sqlite3_module fts3Module = {
+  /* iVersion      */ 0,
+  /* xCreate       */ fulltextCreate,
+  /* xConnect      */ fulltextConnect,
+  /* xBestIndex    */ fulltextBestIndex,
+  /* xDisconnect   */ fulltextDisconnect,
+  /* xDestroy      */ fulltextDestroy,
+  /* xOpen         */ fulltextOpen,
+  /* xClose        */ fulltextClose,
+  /* xFilter       */ fulltextFilter,
+  /* xNext         */ fulltextNext,
+  /* xEof          */ fulltextEof,
+  /* xColumn       */ fulltextColumn,
+  /* xRowid        */ fulltextRowid,
+  /* xUpdate       */ fulltextUpdate,
+  /* xBegin        */ fulltextBegin,
+  /* xSync         */ fulltextSync,
+  /* xCommit       */ fulltextCommit,
+  /* xRollback     */ fulltextRollback,
+  /* xFindFunction */ fulltextFindFunction,
+  /* xRename */       fulltextRename,
+};
+
+static void hashDestroy(void *p){
+  fts3Hash *pHash = (fts3Hash *)p;
+  sqlite3Fts3HashClear(pHash);
+  sqlite3_free(pHash);
+}
+
+/*
+** The fts3 built-in tokenizers - "simple" and "porter" - are implemented
+** in files fts3_tokenizer1.c and fts3_porter.c respectively. The following
+** two forward declarations are for functions declared in these files
+** used to retrieve the respective implementations.
+**
+** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
+** to by the argument to point a the "simple" tokenizer implementation.
+** Function ...PorterTokenizerModule() sets *pModule to point to the
+** porter tokenizer/stemmer implementation.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, fts3Hash *, const char *);
+
+/*
+** Initialise the fts3 extension. If this extension is built as part
+** of the sqlite library, then this function is called directly by
+** SQLite. If fts3 is built as a dynamically loadable extension, this
+** function is called by the sqlite3_extension_init() entry point.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  fts3Hash *pHash = 0;
+  const sqlite3_tokenizer_module *pSimple = 0;
+  const sqlite3_tokenizer_module *pPorter = 0;
+  const sqlite3_tokenizer_module *pIcu = 0;
+
+  sqlite3Fts3SimpleTokenizerModule(&pSimple);
+  sqlite3Fts3PorterTokenizerModule(&pPorter);
+#ifdef SQLITE_ENABLE_ICU
+  sqlite3Fts3IcuTokenizerModule(&pIcu);
+#endif
+
+  /* Allocate and initialise the hash-table used to store tokenizers. */
+  pHash = sqlite3_malloc(sizeof(fts3Hash));
+  if( !pHash ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+  }
+
+  /* Load the built-in tokenizers into the hash table */
+  if( rc==SQLITE_OK ){
+    if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
+     || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter) 
+     || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
+    ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  /* Create the virtual table wrapper around the hash-table and overload 
+  ** the two scalar functions. If this is successful, register the
+  ** module with sqlite.
+  */
+  if( SQLITE_OK==rc 
+   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))
+  ){
+    return sqlite3_create_module_v2(
+        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
+    );
+  }
+
+  /* An error has occured. Delete the hash table and return the error code. */
+  assert( rc!=SQLITE_OK );
+  if( pHash ){
+    sqlite3Fts3HashClear(pHash);
+    sqlite3_free(pHash);
+  }
+  return rc;
+}
+
+#if !SQLITE_CORE
+SQLITE_API int sqlite3_extension_init(
+  sqlite3 *db, 
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3Fts3Init(db);
+}
+#endif
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3.c ************************************************/
+/************** Begin file fts3_hash.c ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables used in SQLite.
+** We've modified it slightly to serve as a standalone hash table
+** implementation for the full-text indexing module.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+
+
+/*
+** Malloc and Free functions
+*/
+static void *fts3HashMalloc(int n){
+  void *p = sqlite3_malloc(n);
+  if( p ){
+    memset(p, 0, n);
+  }
+  return p;
+}
+static void fts3HashFree(void *p){
+  sqlite3_free(p);
+}
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+** keyClass is one of the constants 
+** FTS3_HASH_BINARY or FTS3_HASH_STRING.  The value of keyClass 
+** determines what kind of key the hash table will use.  "copyKey" is
+** true if the hash table should make its own private copy of keys and
+** false if it should just use the supplied pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash *pNew, int keyClass, int copyKey){
+  assert( pNew!=0 );
+  assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
+  pNew->keyClass = keyClass;
+  pNew->copyKey = copyKey;
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash *pH){
+  fts3HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  fts3HashFree(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    fts3HashElem *next_elem = elem->next;
+    if( pH->copyKey && elem->pKey ){
+      fts3HashFree(elem->pKey);
+    }
+    fts3HashFree(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_STRING
+*/
+static int fts3StrHash(const void *pKey, int nKey){
+  const char *z = (const char *)pKey;
+  int h = 0;
+  if( nKey<=0 ) nKey = (int) strlen(z);
+  while( nKey > 0  ){
+    h = (h<<3) ^ h ^ *z++;
+    nKey--;
+  }
+  return h & 0x7fffffff;
+}
+static int fts3StrCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return strncmp((const char*)pKey1,(const char*)pKey2,n1);
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_BINARY
+*/
+static int fts3BinHash(const void *pKey, int nKey){
+  int h = 0;
+  const char *z = (const char *)pKey;
+  while( nKey-- > 0 ){
+    h = (h<<3) ^ h ^ *(z++);
+  }
+  return h & 0x7fffffff;
+}
+static int fts3BinCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return memcmp(pKey1,pKey2,n1);
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** The C syntax in this function definition may be unfamilar to some 
+** programmers, so we provide the following additional explanation:
+**
+** The name of the function is "ftsHashFunction".  The function takes a
+** single parameter "keyClass".  The return value of ftsHashFunction()
+** is a pointer to another function.  Specifically, the return value
+** of ftsHashFunction() is a pointer to a function that takes two parameters
+** with types "const void*" and "int" and returns an "int".
+*/
+static int (*ftsHashFunction(int keyClass))(const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrHash;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinHash;
+  }
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** For help in interpreted the obscure C code in the function definition,
+** see the header comment on the previous function.
+*/
+static int (*ftsCompareFunction(int keyClass))(const void*,int,const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrCompare;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinCompare;
+  }
+}
+
+/* Link an element into the hash table
+*/
+static void fts3HashInsertElement(
+  fts3Hash *pH,            /* The complete hash table */
+  struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
+  fts3HashElem *pNew       /* The element to be inserted */
+){
+  fts3HashElem *pHead;     /* First element already in pEntry */
+  pHead = pEntry->chain;
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+  pEntry->count++;
+  pEntry->chain = pNew;
+}
+
+
+/* Resize the hash table so that it cantains "new_size" buckets.
+** "new_size" must be a power of 2.  The hash table might fail 
+** to resize if sqliteMalloc() fails.
+*/
+static void fts3Rehash(fts3Hash *pH, int new_size){
+  struct _fts3ht *new_ht;          /* The new hash table */
+  fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
+  int (*xHash)(const void*,int);   /* The hash function */
+
+  assert( (new_size & (new_size-1))==0 );
+  new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
+  if( new_ht==0 ) return;
+  fts3HashFree(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size;
+  xHash = ftsHashFunction(pH->keyClass);
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
+    next_elem = elem->next;
+    fts3HashInsertElement(pH, &new_ht[h], elem);
+  }
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  The hash for this key has
+** already been computed and is passed as the 4th parameter.
+*/
+static fts3HashElem *fts3FindElementByHash(
+  const fts3Hash *pH, /* The pH to be searched */
+  const void *pKey,   /* The key we are searching for */
+  int nKey,
+  int h               /* The hash for this key. */
+){
+  fts3HashElem *elem;            /* Used to loop thru the element list */
+  int count;                     /* Number of elements left to test */
+  int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
+
+  if( pH->ht ){
+    struct _fts3ht *pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+    xCompare = ftsCompareFunction(pH->keyClass);
+    while( count-- && elem ){
+      if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){ 
+        return elem;
+      }
+      elem = elem->next;
+    }
+  }
+  return 0;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void fts3RemoveElementByHash(
+  fts3Hash *pH,         /* The pH containing "elem" */
+  fts3HashElem* elem,   /* The element to be removed from the pH */
+  int h                 /* Hash value for the element */
+){
+  struct _fts3ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next; 
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  pEntry = &pH->ht[h];
+  if( pEntry->chain==elem ){
+    pEntry->chain = elem->next;
+  }
+  pEntry->count--;
+  if( pEntry->count<=0 ){
+    pEntry->chain = 0;
+  }
+  if( pH->copyKey && elem->pKey ){
+    fts3HashFree(elem->pKey);
+  }
+  fts3HashFree( elem );
+  pH->count--;
+  if( pH->count<=0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    fts3HashClear(pH);
+  }
+}
+
+/* Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash *pH, const void *pKey, int nKey){
+  int h;                 /* A hash on key */
+  fts3HashElem *elem;    /* The element that matches key */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  if( pH==0 || pH->ht==0 ) return 0;
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  h = (*xHash)(pKey,nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  elem = fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
+  return elem ? elem->data : 0;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey,nKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created.  A copy of the key is made if the copyKey
+** flag is set.  NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
+  fts3Hash *pH,        /* The hash table to insert into */
+  const void *pKey,    /* The key */
+  int nKey,            /* Number of bytes in the key */
+  void *data           /* The data */
+){
+  int hraw;                 /* Raw hash value of the key */
+  int h;                    /* the hash of the key modulo hash table size */
+  fts3HashElem *elem;       /* Used to loop thru the element list */
+  fts3HashElem *new_elem;   /* New element added to the pH */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  assert( pH!=0 );
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  hraw = (*xHash)(pKey, nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  elem = fts3FindElementByHash(pH,pKey,nKey,h);
+  if( elem ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      fts3RemoveElementByHash(pH,elem,h);
+    }else{
+      elem->data = data;
+    }
+    return old_data;
+  }
+  if( data==0 ) return 0;
+  new_elem = (fts3HashElem*)fts3HashMalloc( sizeof(fts3HashElem) );
+  if( new_elem==0 ) return data;
+  if( pH->copyKey && pKey!=0 ){
+    new_elem->pKey = fts3HashMalloc( nKey );
+    if( new_elem->pKey==0 ){
+      fts3HashFree(new_elem);
+      return data;
+    }
+    memcpy((void*)new_elem->pKey, pKey, nKey);
+  }else{
+    new_elem->pKey = (void*)pKey;
+  }
+  new_elem->nKey = nKey;
+  pH->count++;
+  if( pH->htsize==0 ){
+    fts3Rehash(pH,8);
+    if( pH->htsize==0 ){
+      pH->count = 0;
+      fts3HashFree(new_elem);
+      return data;
+    }
+  }
+  if( pH->count > pH->htsize ){
+    fts3Rehash(pH,pH->htsize*2);
+  }
+  assert( pH->htsize>0 );
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  fts3HashInsertElement(pH, &pH->ht[h], new_elem);
+  new_elem->data = data;
+  return 0;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_hash.c *******************************************/
+/************** Begin file fts3_porter.c *************************************/
+/*
+** 2006 September 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Implementation of the full-text-search tokenizer that implements
+** a Porter stemmer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+
+
+
+/*
+** Class derived from sqlite3_tokenizer
+*/
+typedef struct porter_tokenizer {
+  sqlite3_tokenizer base;      /* Base class */
+} porter_tokenizer;
+
+/*
+** Class derived from sqlit3_tokenizer_cursor
+*/
+typedef struct porter_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *zInput;          /* input we are tokenizing */
+  int nInput;                  /* size of the input */
+  int iOffset;                 /* current position in zInput */
+  int iToken;                  /* index of next token to be returned */
+  char *zToken;                /* storage for current token */
+  int nAllocated;              /* space allocated to zToken buffer */
+} porter_tokenizer_cursor;
+
+
+/* Forward declaration */
+static const sqlite3_tokenizer_module porterTokenizerModule;
+
+
+/*
+** Create a new tokenizer instance.
+*/
+static int porterCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  porter_tokenizer *t;
+  t = (porter_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int porterDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is zInput[0..nInput-1].  A cursor
+** used to incrementally tokenize this string is returned in 
+** *ppCursor.
+*/
+static int porterOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *zInput, int nInput,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  porter_tokenizer_cursor *c;
+
+  c = (porter_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->zInput = zInput;
+  if( zInput==0 ){
+    c->nInput = 0;
+  }else if( nInput<0 ){
+    c->nInput = (int)strlen(zInput);
+  }else{
+    c->nInput = nInput;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->zToken = NULL;               /* no space allocated, yet. */
+  c->nAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** porterOpen() above.
+*/
+static int porterClose(sqlite3_tokenizer_cursor *pCursor){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->zToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+/*
+** Vowel or consonant
+*/
+static const char cType[] = {
+   0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0,
+   1, 1, 1, 2, 1
+};
+
+/*
+** isConsonant() and isVowel() determine if their first character in
+** the string they point to is a consonant or a vowel, according
+** to Porter ruls.  
+**
+** A consonate is any letter other than 'a', 'e', 'i', 'o', or 'u'.
+** 'Y' is a consonant unless it follows another consonant,
+** in which case it is a vowel.
+**
+** In these routine, the letters are in reverse order.  So the 'y' rule
+** is that 'y' is a consonant unless it is followed by another
+** consonent.
+*/
+static int isVowel(const char*);
+static int isConsonant(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return j;
+  return z[1]==0 || isVowel(z + 1);
+}
+static int isVowel(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return 1-j;
+  return isConsonant(z + 1);
+}
+
+/*
+** Let any sequence of one or more vowels be represented by V and let
+** C be sequence of one or more consonants.  Then every word can be
+** represented as:
+**
+**           [C] (VC){m} [V]
+**
+** In prose:  A word is an optional consonant followed by zero or
+** vowel-consonant pairs followed by an optional vowel.  "m" is the
+** number of vowel consonant pairs.  This routine computes the value
+** of m for the first i bytes of a word.
+**
+** Return true if the m-value for z is 1 or more.  In other words,
+** return true if z contains at least one vowel that is followed
+** by a consonant.
+**
+** In this routine z[] is in reverse order.  So we are really looking
+** for an instance of of a consonant followed by a vowel.
+*/
+static int m_gt_0(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/* Like mgt0 above except we are looking for a value of m which is
+** exactly 1
+*/
+static int m_eq_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 1;
+  while( isConsonant(z) ){ z++; }
+  return *z==0;
+}
+
+/* Like mgt0 above except we are looking for a value of m>1 instead
+** or m>0
+*/
+static int m_gt_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if there is a vowel anywhere within z[0..n-1]
+*/
+static int hasVowel(const char *z){
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if the word ends in a double consonant.
+**
+** The text is reversed here. So we are really looking at
+** the first two characters of z[].
+*/
+static int doubleConsonant(const char *z){
+  return isConsonant(z) && z[0]==z[1] && isConsonant(z+1);
+}
+
+/*
+** Return TRUE if the word ends with three letters which
+** are consonant-vowel-consonent and where the final consonant
+** is not 'w', 'x', or 'y'.
+**
+** The word is reversed here.  So we are really checking the
+** first three letters and the first one cannot be in [wxy].
+*/
+static int star_oh(const char *z){
+  return
+    z[0]!=0 && isConsonant(z) &&
+    z[0]!='w' && z[0]!='x' && z[0]!='y' &&
+    z[1]!=0 && isVowel(z+1) &&
+    z[2]!=0 && isConsonant(z+2);
+}
+
+/*
+** If the word ends with zFrom and xCond() is true for the stem
+** of the word that preceeds the zFrom ending, then change the 
+** ending to zTo.
+**
+** The input word *pz and zFrom are both in reverse order.  zTo
+** is in normal order. 
+**
+** Return TRUE if zFrom matches.  Return FALSE if zFrom does not
+** match.  Not that TRUE is returned even if xCond() fails and
+** no substitution occurs.
+*/
+static int stem(
+  char **pz,             /* The word being stemmed (Reversed) */
+  const char *zFrom,     /* If the ending matches this... (Reversed) */
+  const char *zTo,       /* ... change the ending to this (not reversed) */
+  int (*xCond)(const char*)   /* Condition that must be true */
+){
+  char *z = *pz;
+  while( *zFrom && *zFrom==*z ){ z++; zFrom++; }
+  if( *zFrom!=0 ) return 0;
+  if( xCond && !xCond(z) ) return 1;
+  while( *zTo ){
+    *(--z) = *(zTo++);
+  }
+  *pz = z;
+  return 1;
+}
+
+/*
+** This is the fallback stemmer used when the porter stemmer is
+** inappropriate.  The input word is copied into the output with
+** US-ASCII case folding.  If the input word is too long (more
+** than 20 bytes if it contains no digits or more than 6 bytes if
+** it contains digits) then word is truncated to 20 or 6 bytes
+** by taking 10 or 3 bytes from the beginning and end.
+*/
+static void copy_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, mx, j;
+  int hasDigit = 0;
+  for(i=0; i<nIn; i++){
+    int c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zOut[i] = c - 'A' + 'a';
+    }else{
+      if( c>='0' && c<='9' ) hasDigit = 1;
+      zOut[i] = c;
+    }
+  }
+  mx = hasDigit ? 3 : 10;
+  if( nIn>mx*2 ){
+    for(j=mx, i=nIn-mx; i<nIn; i++, j++){
+      zOut[j] = zOut[i];
+    }
+    i = j;
+  }
+  zOut[i] = 0;
+  *pnOut = i;
+}
+
+
+/*
+** Stem the input word zIn[0..nIn-1].  Store the output in zOut.
+** zOut is at least big enough to hold nIn bytes.  Write the actual
+** size of the output word (exclusive of the '\0' terminator) into *pnOut.
+**
+** Any upper-case characters in the US-ASCII character set ([A-Z])
+** are converted to lower case.  Upper-case UTF characters are
+** unchanged.
+**
+** Words that are longer than about 20 bytes are stemmed by retaining
+** a few bytes from the beginning and the end of the word.  If the
+** word contains digits, 3 bytes are taken from the beginning and
+** 3 bytes from the end.  For long words without digits, 10 bytes
+** are taken from each end.  US-ASCII case folding still applies.
+** 
+** If the input word contains not digits but does characters not 
+** in [a-zA-Z] then no stemming is attempted and this routine just 
+** copies the input into the input into the output with US-ASCII
+** case folding.
+**
+** Stemming never increases the length of the word.  So there is
+** no chance of overflowing the zOut buffer.
+*/
+static void porter_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, j, c;
+  char zReverse[28];
+  char *z, *z2;
+  if( nIn<3 || nIn>=sizeof(zReverse)-7 ){
+    /* The word is too big or too small for the porter stemmer.
+    ** Fallback to the copy stemmer */
+    copy_stemmer(zIn, nIn, zOut, pnOut);
+    return;
+  }
+  for(i=0, j=sizeof(zReverse)-6; i<nIn; i++, j--){
+    c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zReverse[j] = c + 'a' - 'A';
+    }else if( c>='a' && c<='z' ){
+      zReverse[j] = c;
+    }else{
+      /* The use of a character not in [a-zA-Z] means that we fallback
+      ** to the copy stemmer */
+      copy_stemmer(zIn, nIn, zOut, pnOut);
+      return;
+    }
+  }
+  memset(&zReverse[sizeof(zReverse)-5], 0, 5);
+  z = &zReverse[j+1];
+
+
+  /* Step 1a */
+  if( z[0]=='s' ){
+    if(
+     !stem(&z, "sess", "ss", 0) &&
+     !stem(&z, "sei", "i", 0)  &&
+     !stem(&z, "ss", "ss", 0)
+    ){
+      z++;
+    }
+  }
+
+  /* Step 1b */  
+  z2 = z;
+  if( stem(&z, "dee", "ee", m_gt_0) ){
+    /* Do nothing.  The work was all in the test */
+  }else if( 
+     (stem(&z, "gni", "", hasVowel) || stem(&z, "de", "", hasVowel))
+      && z!=z2
+  ){
+     if( stem(&z, "ta", "ate", 0) ||
+         stem(&z, "lb", "ble", 0) ||
+         stem(&z, "zi", "ize", 0) ){
+       /* Do nothing.  The work was all in the test */
+     }else if( doubleConsonant(z) && (*z!='l' && *z!='s' && *z!='z') ){
+       z++;
+     }else if( m_eq_1(z) && star_oh(z) ){
+       *(--z) = 'e';
+     }
+  }
+
+  /* Step 1c */
+  if( z[0]=='y' && hasVowel(z+1) ){
+    z[0] = 'i';
+  }
+
+  /* Step 2 */
+  switch( z[1] ){
+   case 'a':
+     stem(&z, "lanoita", "ate", m_gt_0) ||
+     stem(&z, "lanoit", "tion", m_gt_0);
+     break;
+   case 'c':
+     stem(&z, "icne", "ence", m_gt_0) ||
+     stem(&z, "icna", "ance", m_gt_0);
+     break;
+   case 'e':
+     stem(&z, "rezi", "ize", m_gt_0);
+     break;
+   case 'g':
+     stem(&z, "igol", "log", m_gt_0);
+     break;
+   case 'l':
+     stem(&z, "ilb", "ble", m_gt_0) ||
+     stem(&z, "illa", "al", m_gt_0) ||
+     stem(&z, "iltne", "ent", m_gt_0) ||
+     stem(&z, "ile", "e", m_gt_0) ||
+     stem(&z, "ilsuo", "ous", m_gt_0);
+     break;
+   case 'o':
+     stem(&z, "noitazi", "ize", m_gt_0) ||
+     stem(&z, "noita", "ate", m_gt_0) ||
+     stem(&z, "rota", "ate", m_gt_0);
+     break;
+   case 's':
+     stem(&z, "msila", "al", m_gt_0) ||
+     stem(&z, "ssenevi", "ive", m_gt_0) ||
+     stem(&z, "ssenluf", "ful", m_gt_0) ||
+     stem(&z, "ssensuo", "ous", m_gt_0);
+     break;
+   case 't':
+     stem(&z, "itila", "al", m_gt_0) ||
+     stem(&z, "itivi", "ive", m_gt_0) ||
+     stem(&z, "itilib", "ble", m_gt_0);
+     break;
+  }
+
+  /* Step 3 */
+  switch( z[0] ){
+   case 'e':
+     stem(&z, "etaci", "ic", m_gt_0) ||
+     stem(&z, "evita", "", m_gt_0)   ||
+     stem(&z, "ezila", "al", m_gt_0);
+     break;
+   case 'i':
+     stem(&z, "itici", "ic", m_gt_0);
+     break;
+   case 'l':
+     stem(&z, "laci", "ic", m_gt_0) ||
+     stem(&z, "luf", "", m_gt_0);
+     break;
+   case 's':
+     stem(&z, "ssen", "", m_gt_0);
+     break;
+  }
+
+  /* Step 4 */
+  switch( z[1] ){
+   case 'a':
+     if( z[0]=='l' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'c':
+     if( z[0]=='e' && z[2]=='n' && (z[3]=='a' || z[3]=='e')  && m_gt_1(z+4)  ){
+       z += 4;
+     }
+     break;
+   case 'e':
+     if( z[0]=='r' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'i':
+     if( z[0]=='c' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'l':
+     if( z[0]=='e' && z[2]=='b' && (z[3]=='a' || z[3]=='i') && m_gt_1(z+4) ){
+       z += 4;
+     }
+     break;
+   case 'n':
+     if( z[0]=='t' ){
+       if( z[2]=='a' ){
+         if( m_gt_1(z+3) ){
+           z += 3;
+         }
+       }else if( z[2]=='e' ){
+         stem(&z, "tneme", "", m_gt_1) ||
+         stem(&z, "tnem", "", m_gt_1) ||
+         stem(&z, "tne", "", m_gt_1);
+       }
+     }
+     break;
+   case 'o':
+     if( z[0]=='u' ){
+       if( m_gt_1(z+2) ){
+         z += 2;
+       }
+     }else if( z[3]=='s' || z[3]=='t' ){
+       stem(&z, "noi", "", m_gt_1);
+     }
+     break;
+   case 's':
+     if( z[0]=='m' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 't':
+     stem(&z, "eta", "", m_gt_1) ||
+     stem(&z, "iti", "", m_gt_1);
+     break;
+   case 'u':
+     if( z[0]=='s' && z[2]=='o' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 'v':
+   case 'z':
+     if( z[0]=='e' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+  }
+
+  /* Step 5a */
+  if( z[0]=='e' ){
+    if( m_gt_1(z+1) ){
+      z++;
+    }else if( m_eq_1(z+1) && !star_oh(z+1) ){
+      z++;
+    }
+  }
+
+  /* Step 5b */
+  if( m_gt_1(z) && z[0]=='l' && z[1]=='l' ){
+    z++;
+  }
+
+  /* z[] is now the stemmed word in reverse order.  Flip it back
+  ** around into forward order and return.
+  */
+  *pnOut = i = strlen(z);
+  zOut[i] = 0;
+  while( *z ){
+    zOut[--i] = *(z++);
+  }
+}
+
+/*
+** Characters that can be part of a token.  We assume any character
+** whose value is greater than 0x80 (any UTF character) can be
+** part of a token.  In other words, delimiters all must have
+** values of 0x7f or lower.
+*/
+static const char porterIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+};
+#define isDelim(C) (((ch=C)&0x80)==0 && (ch<0x30 || !porterIdChar[ch-0x30]))
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to porterOpen().
+*/
+static int porterNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by porterOpen */
+  const char **pzToken,               /* OUT: *pzToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  const char *z = c->zInput;
+
+  while( c->iOffset<c->nInput ){
+    int iStartOffset, ch;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nInput && isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nInput && !isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int n = c->iOffset-iStartOffset;
+      if( n>c->nAllocated ){
+        c->nAllocated = n+20;
+        c->zToken = sqlite3_realloc(c->zToken, c->nAllocated);
+        if( c->zToken==NULL ) return SQLITE_NOMEM;
+      }
+      porter_stemmer(&z[iStartOffset], n, c->zToken, pnBytes);
+      *pzToken = c->zToken;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the porter-stemmer tokenizer
+*/
+static const sqlite3_tokenizer_module porterTokenizerModule = {
+  0,
+  porterCreate,
+  porterDestroy,
+  porterOpen,
+  porterClose,
+  porterNext,
+};
+
+/*
+** Allocate a new porter tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &porterTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_porter.c *****************************************/
+/************** Begin file fts3_tokenizer.c **********************************/
+/*
+** 2007 June 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is part of an SQLite module implementing full-text search.
+** This particular file implements the generic tokenizer interface.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#ifndef SQLITE_CORE
+  SQLITE_EXTENSION_INIT1
+#endif
+
+
+/*
+** Implementation of the SQL scalar function for accessing the underlying 
+** hash table. This function may be called as follows:
+**
+**   SELECT <function-name>(<key-name>);
+**   SELECT <function-name>(<key-name>, <pointer>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer').
+**
+** If the <pointer> argument is specified, it must be a blob value
+** containing a pointer to be stored as the hash data corresponding
+** to the string <key-name>. If <pointer> is not specified, then
+** the string <key-name> must already exist in the has table. Otherwise,
+** an error is returned.
+**
+** Whether or not the <pointer> argument is specified, the value returned
+** is a blob containing the pointer stored as the hash data corresponding
+** to string <key-name> (after the hash-table is updated, if applicable).
+*/
+static void scalarFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3Hash *pHash;
+  void *pPtr = 0;
+  const unsigned char *zName;
+  int nName;
+
+  assert( argc==1 || argc==2 );
+
+  pHash = (fts3Hash *)sqlite3_user_data(context);
+
+  zName = sqlite3_value_text(argv[0]);
+  nName = sqlite3_value_bytes(argv[0])+1;
+
+  if( argc==2 ){
+    void *pOld;
+    int n = sqlite3_value_bytes(argv[1]);
+    if( n!=sizeof(pPtr) ){
+      sqlite3_result_error(context, "argument type mismatch", -1);
+      return;
+    }
+    pPtr = *(void **)sqlite3_value_blob(argv[1]);
+    pOld = sqlite3Fts3HashInsert(pHash, (void *)zName, nName, pPtr);
+    if( pOld==pPtr ){
+      sqlite3_result_error(context, "out of memory", -1);
+      return;
+    }
+  }else{
+    pPtr = sqlite3Fts3HashFind(pHash, zName, nName);
+    if( !pPtr ){
+      char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
+      sqlite3_result_error(context, zErr, -1);
+      sqlite3_free(zErr);
+      return;
+    }
+  }
+
+  sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
+}
+
+#ifdef SQLITE_TEST
+
+
+/*
+** Implementation of a special SQL scalar function for testing tokenizers 
+** designed to be used in concert with the Tcl testing framework. This
+** function must be called with two arguments:
+**
+**   SELECT <function-name>(<key-name>, <input-string>);
+**   SELECT <function-name>(<key-name>, <pointer>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
+** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
+**
+** The return value is a string that may be interpreted as a Tcl
+** list. For each token in the <input-string>, three elements are
+** added to the returned list. The first is the token position, the 
+** second is the token text (folded, stemmed, etc.) and the third is the
+** substring of <input-string> associated with the token. For example, 
+** using the built-in "simple" tokenizer:
+**
+**   SELECT fts_tokenizer_test('simple', 'I don't see how');
+**
+** will return the string:
+**
+**   "{0 i I 1 dont don't 2 see see 3 how how}"
+**   
+*/
+static void testFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3Hash *pHash;
+  sqlite3_tokenizer_module *p;
+  sqlite3_tokenizer *pTokenizer = 0;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+
+  const char *zErr = 0;
+
+  const char *zName;
+  int nName;
+  const char *zInput;
+  int nInput;
+
+  const char *zArg = 0;
+
+  const char *zToken;
+  int nToken;
+  int iStart;
+  int iEnd;
+  int iPos;
+
+  Tcl_Obj *pRet;
+
+  assert( argc==2 || argc==3 );
+
+  nName = sqlite3_value_bytes(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[0]);
+  nInput = sqlite3_value_bytes(argv[argc-1]);
+  zInput = (const char *)sqlite3_value_text(argv[argc-1]);
+
+  if( argc==3 ){
+    zArg = (const char *)sqlite3_value_text(argv[1]);
+  }
+
+  pHash = (fts3Hash *)sqlite3_user_data(context);
+  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
+
+  if( !p ){
+    char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
+    sqlite3_result_error(context, zErr, -1);
+    sqlite3_free(zErr);
+    return;
+  }
+
+  pRet = Tcl_NewObj();
+  Tcl_IncrRefCount(pRet);
+
+  if( SQLITE_OK!=p->xCreate(zArg ? 1 : 0, &zArg, &pTokenizer) ){
+    zErr = "error in xCreate()";
+    goto finish;
+  }
+  pTokenizer->pModule = p;
+  if( SQLITE_OK!=p->xOpen(pTokenizer, zInput, nInput, &pCsr) ){
+    zErr = "error in xOpen()";
+    goto finish;
+  }
+  pCsr->pTokenizer = pTokenizer;
+
+  while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+    zToken = &zInput[iStart];
+    nToken = iEnd-iStart;
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+  }
+
+  if( SQLITE_OK!=p->xClose(pCsr) ){
+    zErr = "error in xClose()";
+    goto finish;
+  }
+  if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
+    zErr = "error in xDestroy()";
+    goto finish;
+  }
+
+finish:
+  if( zErr ){
+    sqlite3_result_error(context, zErr, -1);
+  }else{
+    sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
+  }
+  Tcl_DecrRefCount(pRet);
+}
+
+static
+int registerTokenizer(
+  sqlite3 *db, 
+  char *zName, 
+  const sqlite3_tokenizer_module *p
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?, ?)";
+
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
+  sqlite3_step(pStmt);
+
+  return sqlite3_finalize(pStmt);
+}
+
+static
+int queryTokenizer(
+  sqlite3 *db, 
+  char *zName,  
+  const sqlite3_tokenizer_module **pp
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?)";
+
+  *pp = 0;
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
+      memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+    }
+  }
+
+  return sqlite3_finalize(pStmt);
+}
+
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+/*
+** Implementation of the scalar function fts3_tokenizer_internal_test().
+** This function is used for testing only, it is not included in the
+** build unless SQLITE_TEST is defined.
+**
+** The purpose of this is to test that the fts3_tokenizer() function
+** can be used as designed by the C-code in the queryTokenizer and
+** registerTokenizer() functions above. These two functions are repeated
+** in the README.tokenizer file as an example, so it is important to
+** test them.
+**
+** To run the tests, evaluate the fts3_tokenizer_internal_test() scalar
+** function with no arguments. An assert() will fail if a problem is
+** detected. i.e.:
+**
+**     SELECT fts3_tokenizer_internal_test();
+**
+*/
+static void intTestFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int rc;
+  const sqlite3_tokenizer_module *p1;
+  const sqlite3_tokenizer_module *p2;
+  sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
+
+  /* Test the query function */
+  sqlite3Fts3SimpleTokenizerModule(&p1);
+  rc = queryTokenizer(db, "simple", &p2);
+  assert( rc==SQLITE_OK );
+  assert( p1==p2 );
+  rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+  assert( rc==SQLITE_ERROR );
+  assert( p2==0 );
+  assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
+
+  /* Test the storage function */
+  rc = registerTokenizer(db, "nosuchtokenizer", p1);
+  assert( rc==SQLITE_OK );
+  rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+  assert( rc==SQLITE_OK );
+  assert( p2==p1 );
+
+  sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
+}
+
+#endif
+
+/*
+** Set up SQL objects in database db used to access the contents of
+** the hash table pointed to by argument pHash. The hash table must
+** been initialised to use string keys, and to take a private copy 
+** of the key when a value is inserted. i.e. by a call similar to:
+**
+**    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+**
+** This function adds a scalar function (see header comment above
+** scalarFunc() in this file for details) and, if ENABLE_TABLE is
+** defined at compilation time, a temporary virtual table (see header 
+** comment above struct HashTableVtab) to the database schema. Both 
+** provide read/write access to the contents of *pHash.
+**
+** The third argument to this function, zName, is used as the name
+** of both the scalar and, if created, the virtual table.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
+  sqlite3 *db, 
+  fts3Hash *pHash, 
+  const char *zName
+){
+  int rc = SQLITE_OK;
+  void *p = (void *)pHash;
+  const int any = SQLITE_ANY;
+  char *zTest = 0;
+  char *zTest2 = 0;
+
+#ifdef SQLITE_TEST
+  void *pdb = (void *)db;
+  zTest = sqlite3_mprintf("%s_test", zName);
+  zTest2 = sqlite3_mprintf("%s_internal_test", zName);
+  if( !zTest || !zTest2 ){
+    rc = SQLITE_NOMEM;
+  }
+#endif
+
+  if( rc!=SQLITE_OK
+   || (rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0))
+   || (rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0))
+#ifdef SQLITE_TEST
+   || (rc = sqlite3_create_function(db, zTest, 2, any, p, testFunc, 0, 0))
+   || (rc = sqlite3_create_function(db, zTest, 3, any, p, testFunc, 0, 0))
+   || (rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0))
+#endif
+  );
+
+  sqlite3_free(zTest);
+  sqlite3_free(zTest2);
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer.c **************************************/
+/************** Begin file fts3_tokenizer1.c *********************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "simple" full-text-search tokenizer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+
+
+
+typedef struct simple_tokenizer {
+  sqlite3_tokenizer base;
+  char delim[128];             /* flag ASCII delimiters */
+} simple_tokenizer;
+
+typedef struct simple_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *pInput;          /* input we are tokenizing */
+  int nBytes;                  /* size of the input */
+  int iOffset;                 /* current position in pInput */
+  int iToken;                  /* index of next token to be returned */
+  char *pToken;                /* storage for current token */
+  int nTokenAllocated;         /* space allocated to zToken buffer */
+} simple_tokenizer_cursor;
+
+
+/* Forward declaration */
+static const sqlite3_tokenizer_module simpleTokenizerModule;
+
+static int simpleDelim(simple_tokenizer *t, unsigned char c){
+  return c<0x80 && t->delim[c];
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int simpleCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  simple_tokenizer *t;
+
+  t = (simple_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+
+  /* TODO(shess) Delimiters need to remain the same from run to run,
+  ** else we need to reindex.  One solution would be a meta-table to
+  ** track such information in the database, then we'd only want this
+  ** information on the initial create.
+  */
+  if( argc>1 ){
+    int i, n = strlen(argv[1]);
+    for(i=0; i<n; i++){
+      unsigned char ch = argv[1][i];
+      /* We explicitly don't support UTF-8 delimiters for now. */
+      if( ch>=0x80 ){
+        sqlite3_free(t);
+        return SQLITE_ERROR;
+      }
+      t->delim[ch] = 1;
+    }
+  } else {
+    /* Mark non-alphanumeric ASCII characters as delimiters */
+    int i;
+    for(i=1; i<0x80; i++){
+      t->delim[i] = !isalnum(i);
+    }
+  }
+
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int simpleDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in 
+** *ppCursor.
+*/
+static int simpleOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *pInput, int nBytes,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  simple_tokenizer_cursor *c;
+
+  c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->pInput = pInput;
+  if( pInput==0 ){
+    c->nBytes = 0;
+  }else if( nBytes<0 ){
+    c->nBytes = (int)strlen(pInput);
+  }else{
+    c->nBytes = nBytes;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->pToken = NULL;               /* no space allocated, yet. */
+  c->nTokenAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int simpleClose(sqlite3_tokenizer_cursor *pCursor){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->pToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int simpleNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
+  const char **ppToken,               /* OUT: *ppToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer;
+  unsigned char *p = (unsigned char *)c->pInput;
+
+  while( c->iOffset<c->nBytes ){
+    int iStartOffset;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nBytes && simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nBytes && !simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int i, n = c->iOffset-iStartOffset;
+      if( n>c->nTokenAllocated ){
+        c->nTokenAllocated = n+20;
+        c->pToken = sqlite3_realloc(c->pToken, c->nTokenAllocated);
+        if( c->pToken==NULL ) return SQLITE_NOMEM;
+      }
+      for(i=0; i<n; i++){
+        /* TODO(shess) This needs expansion to handle UTF-8
+        ** case-insensitivity.
+        */
+        unsigned char ch = p[iStartOffset+i];
+        c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
+      }
+      *ppToken = c->pToken;
+      *pnBytes = n;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the simple tokenizer
+*/
+static const sqlite3_tokenizer_module simpleTokenizerModule = {
+  0,
+  simpleCreate,
+  simpleDestroy,
+  simpleOpen,
+  simpleClose,
+  simpleNext,
+};
+
+/*
+** Allocate a new simple tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &simpleTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer1.c *************************************/