Merge commit '9966985d896629eede849a84f18e406d1164a16c' as 'tcl8.6'

1 files changed, 3128 insertions, 0 deletions

diff --git a/tcl8.6/generic/tclStringObj.c b/tcl8.6/generic/tclStringObj.c
new file mode 100644
index 0000000..11a57e9
--- /dev/null
+++ b/tcl8.6/generic/tclStringObj.c
@@ -0,0 +1,3128 @@
+/*
+ * tclStringObj.c --
+ *
+ *	This file contains functions that implement string operations on Tcl
+ *	objects. Some string operations work with UTF strings and others
+ *	require Unicode format. Functions that require knowledge of the width
+ *	of each character, such as indexing, operate on Unicode data.
+ *
+ *	A Unicode string is an internationalized string. Conceptually, a
+ *	Unicode string is an array of 16-bit quantities organized as a
+ *	sequence of properly formed UTF-8 characters. There is a one-to-one
+ *	map between Unicode and UTF characters. Because Unicode characters
+ *	have a fixed width, operations such as indexing operate on Unicode
+ *	data. The String object is optimized for the case where each UTF char
+ *	in a string is only one byte. In this case, we store the value of
+ *	numChars, but we don't store the Unicode data (unless Tcl_GetUnicode
+ *	is explicitly called).
+ *
+ *	The String object type stores one or both formats. The default
+ *	behavior is to store UTF. Once Unicode is calculated by a function, it
+ *	is stored in the internal rep for future access (without an additional
+ *	O(n) cost).
+ *
+ *	To allow many appends to be done to an object without constantly
+ *	reallocating the space for the string or Unicode representation, we
+ *	allocate double the space for the string or Unicode and use the
+ *	internal representation to keep track of how much space is used vs.
+ *	allocated.
+ *
+ * Copyright (c) 1995-1997 Sun Microsystems, Inc.
+ * Copyright (c) 1999 by Scriptics Corporation.
+ *
+ * See the file "license.terms" for information on usage and redistribution of
+ * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ */
+
+#include "tclInt.h"
+#include "tommath.h"
+#include "tclStringRep.h"
+
+/*
+ * Set COMPAT to 1 to restore the shimmering patterns to those of Tcl 8.5.
+ * This is an escape hatch in case the changes have some unexpected unwelcome
+ * impact on performance. If things go well, this mechanism can go away when
+ * post-8.6 development begins.
+ */
+
+#define COMPAT 0
+
+/*
+ * Prototypes for functions defined later in this file:
+ */
+
+static void		AppendPrintfToObjVA(Tcl_Obj *objPtr,
+			    const char *format, va_list argList);
+static void		AppendUnicodeToUnicodeRep(Tcl_Obj *objPtr,
+			    const Tcl_UniChar *unicode, int appendNumChars);
+static void		AppendUnicodeToUtfRep(Tcl_Obj *objPtr,
+			    const Tcl_UniChar *unicode, int numChars);
+static void		AppendUtfToUnicodeRep(Tcl_Obj *objPtr,
+			    const char *bytes, int numBytes);
+static void		AppendUtfToUtfRep(Tcl_Obj *objPtr,
+			    const char *bytes, int numBytes);
+static void		DupStringInternalRep(Tcl_Obj *objPtr,
+			    Tcl_Obj *copyPtr);
+static int		ExtendStringRepWithUnicode(Tcl_Obj *objPtr,
+			    const Tcl_UniChar *unicode, int numChars);
+static void		ExtendUnicodeRepWithString(Tcl_Obj *objPtr,
+			    const char *bytes, int numBytes,
+			    int numAppendChars);
+static void		FillUnicodeRep(Tcl_Obj *objPtr);
+static void		FreeStringInternalRep(Tcl_Obj *objPtr);
+static void		GrowStringBuffer(Tcl_Obj *objPtr, int needed, int flag);
+static void		GrowUnicodeBuffer(Tcl_Obj *objPtr, int needed);
+static int		SetStringFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr);
+static void		SetUnicodeObj(Tcl_Obj *objPtr,
+			    const Tcl_UniChar *unicode, int numChars);
+static int		UnicodeLength(const Tcl_UniChar *unicode);
+static void		UpdateStringOfString(Tcl_Obj *objPtr);
+
+/*
+ * The structure below defines the string Tcl object type by means of
+ * functions that can be invoked by generic object code.
+ */
+
+const Tcl_ObjType tclStringType = {
+    "string",			/* name */
+    FreeStringInternalRep,	/* freeIntRepPro */
+    DupStringInternalRep,	/* dupIntRepProc */
+    UpdateStringOfString,	/* updateStringProc */
+    SetStringFromAny		/* setFromAnyProc */
+};
+
+/*
+ * TCL STRING GROWTH ALGORITHM
+ *
+ * When growing strings (during an append, for example), the following growth
+ * algorithm is used:
+ *
+ *   Attempt to allocate 2 * (originalLength + appendLength)
+ *   On failure:
+ *	attempt to allocate originalLength + 2*appendLength + TCL_MIN_GROWTH
+ *
+ * This algorithm allows very good performance, as it rapidly increases the
+ * memory allocated for a given string, which minimizes the number of
+ * reallocations that must be performed. However, using only the doubling
+ * algorithm can lead to a significant waste of memory. In particular, it may
+ * fail even when there is sufficient memory available to complete the append
+ * request (but there is not 2*totalLength memory available). So when the
+ * doubling fails (because there is not enough memory available), the
+ * algorithm requests a smaller amount of memory, which is still enough to
+ * cover the request, but which hopefully will be less than the total
+ * available memory.
+ *
+ * The addition of TCL_MIN_GROWTH allows for efficient handling of very
+ * small appends. Without this extra slush factor, a sequence of several small
+ * appends would cause several memory allocations. As long as
+ * TCL_MIN_GROWTH is a reasonable size, we can avoid that behavior.
+ *
+ * The growth algorithm can be tuned by adjusting the following parameters:
+ *
+ * TCL_MIN_GROWTH		Additional space, in bytes, to allocate when
+ *				the double allocation has failed. Default is
+ *				1024 (1 kilobyte).  See tclInt.h.
+ */
+
+#ifndef TCL_MIN_UNICHAR_GROWTH
+#define TCL_MIN_UNICHAR_GROWTH	TCL_MIN_GROWTH/sizeof(Tcl_UniChar)
+#endif
+
+static void
+GrowStringBuffer(
+    Tcl_Obj *objPtr,
+    int needed,
+    int flag)
+{
+    /*
+     * Pre-conditions:
+     *	objPtr->typePtr == &tclStringType
+     *	needed > stringPtr->allocated
+     *	flag || objPtr->bytes != NULL
+     */
+
+    String *stringPtr = GET_STRING(objPtr);
+    char *ptr = NULL;
+    int attempt;
+
+    if (objPtr->bytes == tclEmptyStringRep) {
+	objPtr->bytes = NULL;
+    }
+    if (flag == 0 || stringPtr->allocated > 0) {
+	attempt = 2 * needed;
+	if (attempt >= 0) {
+	    ptr = attemptckrealloc(objPtr->bytes, attempt + 1);
+	}
+	if (ptr == NULL) {
+	    /*
+	     * Take care computing the amount of modest growth to avoid
+	     * overflow into invalid argument values for attempt.
+	     */
+
+	    unsigned int limit = INT_MAX - needed;
+	    unsigned int extra = needed - objPtr->length + TCL_MIN_GROWTH;
+	    int growth = (int) ((extra > limit) ? limit : extra);
+
+	    attempt = needed + growth;
+	    ptr = attemptckrealloc(objPtr->bytes, attempt + 1);
+	}
+    }
+    if (ptr == NULL) {
+	/*
+	 * First allocation - just big enough; or last chance fallback.
+	 */
+
+	attempt = needed;
+	ptr = ckrealloc(objPtr->bytes, attempt + 1);
+    }
+    objPtr->bytes = ptr;
+    stringPtr->allocated = attempt;
+}
+
+static void
+GrowUnicodeBuffer(
+    Tcl_Obj *objPtr,
+    int needed)
+{
+    /*
+     * Pre-conditions:
+     *	objPtr->typePtr == &tclStringType
+     *	needed > stringPtr->maxChars
+     *	needed < STRING_MAXCHARS
+     */
+
+    String *ptr = NULL, *stringPtr = GET_STRING(objPtr);
+    int attempt;
+
+    if (stringPtr->maxChars > 0) {
+	/*
+	 * Subsequent appends - apply the growth algorithm.
+	 */
+
+	attempt = 2 * needed;
+	if (attempt >= 0 && attempt <= STRING_MAXCHARS) {
+	    ptr = stringAttemptRealloc(stringPtr, attempt);
+	}
+	if (ptr == NULL) {
+	    /*
+	     * Take care computing the amount of modest growth to avoid
+	     * overflow into invalid argument values for attempt.
+	     */
+
+	    unsigned int limit = STRING_MAXCHARS - needed;
+	    unsigned int extra = needed - stringPtr->numChars
+		    + TCL_MIN_UNICHAR_GROWTH;
+	    int growth = (int) ((extra > limit) ? limit : extra);
+
+	    attempt = needed + growth;
+	    ptr = stringAttemptRealloc(stringPtr, attempt);
+	}
+    }
+    if (ptr == NULL) {
+	/*
+	 * First allocation - just big enough; or last chance fallback.
+	 */
+
+	attempt = needed;
+	ptr = stringRealloc(stringPtr, attempt);
+    }
+    stringPtr = ptr;
+    stringPtr->maxChars = attempt;
+    SET_STRING(objPtr, stringPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_NewStringObj --
+ *
+ *	This function is normally called when not debugging: i.e., when
+ *	TCL_MEM_DEBUG is not defined. It creates a new string object and
+ *	initializes it from the byte pointer and length arguments.
+ *
+ *	When TCL_MEM_DEBUG is defined, this function just returns the result
+ *	of calling the debugging version Tcl_DbNewStringObj.
+ *
+ * Results:
+ *	A newly created string object is returned that has ref count zero.
+ *
+ * Side effects:
+ *	The new object's internal string representation will be set to a copy
+ *	of the length bytes starting at "bytes". If "length" is negative, use
+ *	bytes up to the first NUL byte; i.e., assume "bytes" points to a
+ *	C-style NUL-terminated string. The object's type is set to NULL. An
+ *	extra NUL is added to the end of the new object's byte array.
+ *
+ *----------------------------------------------------------------------
+ */
+
+#ifdef TCL_MEM_DEBUG
+#undef Tcl_NewStringObj
+Tcl_Obj *
+Tcl_NewStringObj(
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the new object. */
+    int length)			/* The number of bytes to copy from "bytes"
+				 * when initializing the new object. If
+				 * negative, use bytes up to the first NUL
+				 * byte. */
+{
+    return Tcl_DbNewStringObj(bytes, length, "unknown", 0);
+}
+#else /* if not TCL_MEM_DEBUG */
+Tcl_Obj *
+Tcl_NewStringObj(
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the new object. */
+    int length)			/* The number of bytes to copy from "bytes"
+				 * when initializing the new object. If
+				 * negative, use bytes up to the first NUL
+				 * byte. */
+{
+    Tcl_Obj *objPtr;
+
+    if (length < 0) {
+	length = (bytes? strlen(bytes) : 0);
+    }
+    TclNewStringObj(objPtr, bytes, length);
+    return objPtr;
+}
+#endif /* TCL_MEM_DEBUG */
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_DbNewStringObj --
+ *
+ *	This function is normally called when debugging: i.e., when
+ *	TCL_MEM_DEBUG is defined. It creates new string objects. It is the
+ *	same as the Tcl_NewStringObj function above except that it calls
+ *	Tcl_DbCkalloc directly with the file name and line number from its
+ *	caller. This simplifies debugging since then the [memory active]
+ *	command will report the correct file name and line number when
+ *	reporting objects that haven't been freed.
+ *
+ *	When TCL_MEM_DEBUG is not defined, this function just returns the
+ *	result of calling Tcl_NewStringObj.
+ *
+ * Results:
+ *	A newly created string object is returned that has ref count zero.
+ *
+ * Side effects:
+ *	The new object's internal string representation will be set to a copy
+ *	of the length bytes starting at "bytes". If "length" is negative, use
+ *	bytes up to the first NUL byte; i.e., assume "bytes" points to a
+ *	C-style NUL-terminated string. The object's type is set to NULL. An
+ *	extra NUL is added to the end of the new object's byte array.
+ *
+ *----------------------------------------------------------------------
+ */
+
+#ifdef TCL_MEM_DEBUG
+Tcl_Obj *
+Tcl_DbNewStringObj(
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the new object. */
+    int length,			/* The number of bytes to copy from "bytes"
+				 * when initializing the new object. If
+				 * negative, use bytes up to the first NUL
+				 * byte. */
+    const char *file,		/* The name of the source file calling this
+				 * function; used for debugging. */
+    int line)			/* Line number in the source file; used for
+				 * debugging. */
+{
+    Tcl_Obj *objPtr;
+
+    if (length < 0) {
+	length = (bytes? strlen(bytes) : 0);
+    }
+    TclDbNewObj(objPtr, file, line);
+    TclInitStringRep(objPtr, bytes, length);
+    return objPtr;
+}
+#else /* if not TCL_MEM_DEBUG */
+Tcl_Obj *
+Tcl_DbNewStringObj(
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the new object. */
+    int length,			/* The number of bytes to copy from "bytes"
+				 * when initializing the new object. If
+				 * negative, use bytes up to the first NUL
+				 * byte. */
+    const char *file,		/* The name of the source file calling this
+				 * function; used for debugging. */
+    int line)			/* Line number in the source file; used for
+				 * debugging. */
+{
+    return Tcl_NewStringObj(bytes, length);
+}
+#endif /* TCL_MEM_DEBUG */
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * Tcl_NewUnicodeObj --
+ *
+ *	This function is creates a new String object and initializes it from
+ *	the given Unicode String. If the Utf String is the same size as the
+ *	Unicode string, don't duplicate the data.
+ *
+ * Results:
+ *	The newly created object is returned. This object will have no initial
+ *	string representation. The returned object has a ref count of 0.
+ *
+ * Side effects:
+ *	Memory allocated for new object and copy of Unicode argument.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_NewUnicodeObj(
+    const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
+				 * new object. */
+    int numChars)		/* Number of characters in the unicode
+				 * string. */
+{
+    Tcl_Obj *objPtr;
+
+    TclNewObj(objPtr);
+    SetUnicodeObj(objPtr, unicode, numChars);
+    return objPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetCharLength --
+ *
+ *	Get the length of the Unicode string from the Tcl object.
+ *
+ * Results:
+ *	Pointer to unicode string representing the unicode object.
+ *
+ * Side effects:
+ *	Frees old internal rep. Allocates memory for new "String" internal
+ *	rep.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetCharLength(
+    Tcl_Obj *objPtr)		/* The String object to get the num chars
+				 * of. */
+{
+    String *stringPtr;
+    int numChars;
+
+    /*
+     * Optimize the case where we're really dealing with a bytearray object
+     * without string representation; we don't need to convert to a string to
+     * perform the get-length operation.
+     */
+
+    if (TclIsPureByteArray(objPtr)) {
+	int length;
+
+	(void) Tcl_GetByteArrayFromObj(objPtr, &length);
+	return length;
+    }
+
+    /*
+     * OK, need to work with the object as a string.
+     */
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+    numChars = stringPtr->numChars;
+
+    /*
+     * If numChars is unknown, compute it.
+     */
+
+    if (numChars == -1) {
+	TclNumUtfChars(numChars, objPtr->bytes, objPtr->length);
+	stringPtr->numChars = numChars;
+
+#if COMPAT
+	if (numChars < objPtr->length) {
+	    /*
+	     * Since we've just computed the number of chars, and not all UTF
+	     * chars are 1-byte long, go ahead and populate the unicode
+	     * string.
+	     */
+
+	    FillUnicodeRep(objPtr);
+	}
+#endif
+    }
+    return numChars;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetUniChar --
+ *
+ *	Get the index'th Unicode character from the String object. The index
+ *	is assumed to be in the appropriate range.
+ *
+ * Results:
+ *	Returns the index'th Unicode character in the Object.
+ *
+ * Side effects:
+ *	Fills unichar with the index'th Unicode character.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_UniChar
+Tcl_GetUniChar(
+    Tcl_Obj *objPtr,		/* The object to get the Unicode charater
+				 * from. */
+    int index)			/* Get the index'th Unicode character. */
+{
+    String *stringPtr;
+
+    /*
+     * Optimize the case where we're really dealing with a bytearray object
+     * without string representation; we don't need to convert to a string to
+     * perform the indexing operation.
+     */
+
+    if (TclIsPureByteArray(objPtr)) {
+	unsigned char *bytes = Tcl_GetByteArrayFromObj(objPtr, NULL);
+
+	return (Tcl_UniChar) bytes[index];
+    }
+
+    /*
+     * OK, need to work with the object as a string.
+     */
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->hasUnicode == 0) {
+	/*
+	 * If numChars is unknown, compute it.
+	 */
+
+	if (stringPtr->numChars == -1) {
+	    TclNumUtfChars(stringPtr->numChars, objPtr->bytes, objPtr->length);
+	}
+	if (stringPtr->numChars == objPtr->length) {
+	    return (Tcl_UniChar) objPtr->bytes[index];
+	}
+	FillUnicodeRep(objPtr);
+	stringPtr = GET_STRING(objPtr);
+    }
+    return stringPtr->unicode[index];
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetUnicode --
+ *
+ *	Get the Unicode form of the String object. If the object is not
+ *	already a String object, it will be converted to one. If the String
+ *	object does not have a Unicode rep, then one is create from the UTF
+ *	string format.
+ *
+ * Results:
+ *	Returns a pointer to the object's internal Unicode string.
+ *
+ * Side effects:
+ *	Converts the object to have the String internal rep.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_UniChar *
+Tcl_GetUnicode(
+    Tcl_Obj *objPtr)		/* The object to find the unicode string
+				 * for. */
+{
+    return Tcl_GetUnicodeFromObj(objPtr, NULL);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetUnicodeFromObj --
+ *
+ *	Get the Unicode form of the String object with length. If the object
+ *	is not already a String object, it will be converted to one. If the
+ *	String object does not have a Unicode rep, then one is create from the
+ *	UTF string format.
+ *
+ * Results:
+ *	Returns a pointer to the object's internal Unicode string.
+ *
+ * Side effects:
+ *	Converts the object to have the String internal rep.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_UniChar *
+Tcl_GetUnicodeFromObj(
+    Tcl_Obj *objPtr,		/* The object to find the unicode string
+				 * for. */
+    int *lengthPtr)		/* If non-NULL, the location where the string
+				 * rep's unichar length should be stored. If
+				 * NULL, no length is stored. */
+{
+    String *stringPtr;
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->hasUnicode == 0) {
+	FillUnicodeRep(objPtr);
+	stringPtr = GET_STRING(objPtr);
+    }
+
+    if (lengthPtr != NULL) {
+	*lengthPtr = stringPtr->numChars;
+    }
+    return stringPtr->unicode;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetRange --
+ *
+ *	Create a Tcl Object that contains the chars between first and last of
+ *	the object indicated by "objPtr". If the object is not already a
+ *	String object, convert it to one. The first and last indices are
+ *	assumed to be in the appropriate range.
+ *
+ * Results:
+ *	Returns a new Tcl Object of the String type.
+ *
+ * Side effects:
+ *	Changes the internal rep of "objPtr" to the String type.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_GetRange(
+    Tcl_Obj *objPtr,		/* The Tcl object to find the range of. */
+    int first,			/* First index of the range. */
+    int last)			/* Last index of the range. */
+{
+    Tcl_Obj *newObjPtr;		/* The Tcl object to find the range of. */
+    String *stringPtr;
+
+    /*
+     * Optimize the case where we're really dealing with a bytearray object
+     * without string representation; we don't need to convert to a string to
+     * perform the substring operation.
+     */
+
+    if (TclIsPureByteArray(objPtr)) {
+	unsigned char *bytes = Tcl_GetByteArrayFromObj(objPtr, NULL);
+
+	return Tcl_NewByteArrayObj(bytes+first, last-first+1);
+    }
+
+    /*
+     * OK, need to work with the object as a string.
+     */
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->hasUnicode == 0) {
+	/*
+	 * If numChars is unknown, compute it.
+	 */
+
+	if (stringPtr->numChars == -1) {
+	    TclNumUtfChars(stringPtr->numChars, objPtr->bytes, objPtr->length);
+	}
+	if (stringPtr->numChars == objPtr->length) {
+	    newObjPtr = Tcl_NewStringObj(objPtr->bytes + first, last-first+1);
+
+	    /*
+	     * Since we know the char length of the result, store it.
+	     */
+
+	    SetStringFromAny(NULL, newObjPtr);
+	    stringPtr = GET_STRING(newObjPtr);
+	    stringPtr->numChars = newObjPtr->length;
+	    return newObjPtr;
+	}
+	FillUnicodeRep(objPtr);
+	stringPtr = GET_STRING(objPtr);
+    }
+
+    return Tcl_NewUnicodeObj(stringPtr->unicode + first, last-first+1);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetStringObj --
+ *
+ *	Modify an object to hold a string that is a copy of the bytes
+ *	indicated by the byte pointer and length arguments.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The object's string representation will be set to a copy of the
+ *	"length" bytes starting at "bytes". If "length" is negative, use bytes
+ *	up to the first NUL byte; i.e., assume "bytes" points to a C-style
+ *	NUL-terminated string. The object's old string and internal
+ *	representations are freed and the object's type is set NULL.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_SetStringObj(
+    Tcl_Obj *objPtr,		/* Object whose internal rep to init. */
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the object. */
+    int length)			/* The number of bytes to copy from "bytes"
+				 * when initializing the object. If negative,
+				 * use bytes up to the first NUL byte.*/
+{
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_SetStringObj");
+    }
+
+    /*
+     * Set the type to NULL and free any internal rep for the old type.
+     */
+
+    TclFreeIntRep(objPtr);
+
+    /*
+     * Free any old string rep, then set the string rep to a copy of the
+     * length bytes starting at "bytes".
+     */
+
+    TclInvalidateStringRep(objPtr);
+    if (length < 0) {
+	length = (bytes? strlen(bytes) : 0);
+    }
+    TclInitStringRep(objPtr, bytes, length);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetObjLength --
+ *
+ *	This function changes the length of the string representation of an
+ *	object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If the size of objPtr's string representation is greater than length,
+ *	then it is reduced to length and a new terminating null byte is stored
+ *	in the strength. If the length of the string representation is greater
+ *	than length, the storage space is reallocated to the given length; a
+ *	null byte is stored at the end, but other bytes past the end of the
+ *	original string representation are undefined. The object's internal
+ *	representation is changed to "expendable string".
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_SetObjLength(
+    Tcl_Obj *objPtr,		/* Pointer to object. This object must not
+				 * currently be shared. */
+    int length)			/* Number of bytes desired for string
+				 * representation of object, not including
+				 * terminating null byte. */
+{
+    String *stringPtr;
+
+    if (length < 0) {
+	/*
+	 * Setting to a negative length is nonsense. This is probably the
+	 * result of overflowing the signed integer range.
+	 */
+
+	Tcl_Panic("Tcl_SetObjLength: negative length requested: "
+		"%d (integer overflow?)", length);
+    }
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_SetObjLength");
+    }
+
+    if (objPtr->bytes && objPtr->length == length) {
+	return;
+    }
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (objPtr->bytes != NULL) {
+	/*
+	 * Change length of an existing string rep.
+	 */
+	if (length > stringPtr->allocated) {
+	    /*
+	     * Need to enlarge the buffer.
+	     */
+	    if (objPtr->bytes == tclEmptyStringRep) {
+		objPtr->bytes = ckalloc(length + 1);
+	    } else {
+		objPtr->bytes = ckrealloc(objPtr->bytes, length + 1);
+	    }
+	    stringPtr->allocated = length;
+	}
+
+	objPtr->length = length;
+	objPtr->bytes[length] = 0;
+
+	/*
+	 * Invalidate the unicode data.
+	 */
+
+	stringPtr->numChars = -1;
+	stringPtr->hasUnicode = 0;
+    } else {
+	/*
+	 * Changing length of pure unicode string.
+	 */
+
+	stringCheckLimits(length);
+	if (length > stringPtr->maxChars) {
+	    stringPtr = stringRealloc(stringPtr, length);
+	    SET_STRING(objPtr, stringPtr);
+	    stringPtr->maxChars = length;
+	}
+
+	/*
+	 * Mark the new end of the unicode string
+	 */
+
+	stringPtr->numChars = length;
+	stringPtr->unicode[length] = 0;
+	stringPtr->hasUnicode = 1;
+
+	/*
+	 * Can only get here when objPtr->bytes == NULL. No need to invalidate
+	 * the string rep.
+	 */
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AttemptSetObjLength --
+ *
+ *	This function changes the length of the string representation of an
+ *	object. It uses the attempt* (non-panic'ing) memory allocators.
+ *
+ * Results:
+ *	1 if the requested memory was allocated, 0 otherwise.
+ *
+ * Side effects:
+ *	If the size of objPtr's string representation is greater than length,
+ *	then it is reduced to length and a new terminating null byte is stored
+ *	in the strength. If the length of the string representation is greater
+ *	than length, the storage space is reallocated to the given length; a
+ *	null byte is stored at the end, but other bytes past the end of the
+ *	original string representation are undefined. The object's internal
+ *	representation is changed to "expendable string".
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_AttemptSetObjLength(
+    Tcl_Obj *objPtr,		/* Pointer to object. This object must not
+				 * currently be shared. */
+    int length)			/* Number of bytes desired for string
+				 * representation of object, not including
+				 * terminating null byte. */
+{
+    String *stringPtr;
+
+    if (length < 0) {
+	/*
+	 * Setting to a negative length is nonsense. This is probably the
+	 * result of overflowing the signed integer range.
+	 */
+
+	return 0;
+    }
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_AttemptSetObjLength");
+    }
+    if (objPtr->bytes && objPtr->length == length) {
+	return 1;
+    }
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (objPtr->bytes != NULL) {
+	/*
+	 * Change length of an existing string rep.
+	 */
+	if (length > stringPtr->allocated) {
+	    /*
+	     * Need to enlarge the buffer.
+	     */
+
+	    char *newBytes;
+
+	    if (objPtr->bytes == tclEmptyStringRep) {
+		newBytes = attemptckalloc(length + 1);
+	    } else {
+		newBytes = attemptckrealloc(objPtr->bytes, length + 1);
+	    }
+	    if (newBytes == NULL) {
+		return 0;
+	    }
+	    objPtr->bytes = newBytes;
+	    stringPtr->allocated = length;
+	}
+
+	objPtr->length = length;
+	objPtr->bytes[length] = 0;
+
+	/*
+	 * Invalidate the unicode data.
+	 */
+
+	stringPtr->numChars = -1;
+	stringPtr->hasUnicode = 0;
+    } else {
+	/*
+	 * Changing length of pure unicode string.
+	 */
+
+	if (length > STRING_MAXCHARS) {
+	    return 0;
+	}
+	if (length > stringPtr->maxChars) {
+	    stringPtr = stringAttemptRealloc(stringPtr, length);
+	    if (stringPtr == NULL) {
+		return 0;
+	    }
+	    SET_STRING(objPtr, stringPtr);
+	    stringPtr->maxChars = length;
+	}
+
+	/*
+	 * Mark the new end of the unicode string.
+	 */
+
+	stringPtr->unicode[length] = 0;
+	stringPtr->numChars = length;
+	stringPtr->hasUnicode = 1;
+
+	/*
+	 * Can only get here when objPtr->bytes == NULL. No need to invalidate
+	 * the string rep.
+	 */
+    }
+    return 1;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * Tcl_SetUnicodeObj --
+ *
+ *	Modify an object to hold the Unicode string indicated by "unicode".
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory allocated for new "String" internal rep.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+void
+Tcl_SetUnicodeObj(
+    Tcl_Obj *objPtr,		/* The object to set the string of. */
+    const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
+				 * object. */
+    int numChars)		/* Number of characters in the unicode
+				 * string. */
+{
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_SetUnicodeObj");
+    }
+    TclFreeIntRep(objPtr);
+    SetUnicodeObj(objPtr, unicode, numChars);
+}
+
+static int
+UnicodeLength(
+    const Tcl_UniChar *unicode)
+{
+    int numChars = 0;
+
+    if (unicode) {
+	while (numChars >= 0 && unicode[numChars] != 0) {
+	    numChars++;
+	}
+    }
+    stringCheckLimits(numChars);
+    return numChars;
+}
+
+static void
+SetUnicodeObj(
+    Tcl_Obj *objPtr,		/* The object to set the string of. */
+    const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
+				 * object. */
+    int numChars)		/* Number of characters in the unicode
+				 * string. */
+{
+    String *stringPtr;
+
+    if (numChars < 0) {
+	numChars = UnicodeLength(unicode);
+    }
+
+    /*
+     * Allocate enough space for the String structure + Unicode string.
+     */
+
+    stringCheckLimits(numChars);
+    stringPtr = stringAlloc(numChars);
+    SET_STRING(objPtr, stringPtr);
+    objPtr->typePtr = &tclStringType;
+
+    stringPtr->maxChars = numChars;
+    memcpy(stringPtr->unicode, unicode, numChars * sizeof(Tcl_UniChar));
+    stringPtr->unicode[numChars] = 0;
+    stringPtr->numChars = numChars;
+    stringPtr->hasUnicode = 1;
+
+    TclInvalidateStringRep(objPtr);
+    stringPtr->allocated = 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendLimitedToObj --
+ *
+ *	This function appends a limited number of bytes from a sequence of
+ *	bytes to an object, marking any limitation with an ellipsis.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The bytes at *bytes are appended to the string representation of
+ *	objPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendLimitedToObj(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const char *bytes,		/* Points to the bytes to append to the
+				 * object. */
+    int length,			/* The number of bytes available to be
+				 * appended from "bytes". If < 0, then all
+				 * bytes up to a NUL byte are available. */
+    int limit,			/* The maximum number of bytes to append to
+				 * the object. */
+    const char *ellipsis)	/* Ellipsis marker string, appended to the
+				 * object to indicate not all available bytes
+				 * at "bytes" were appended. */
+{
+    String *stringPtr;
+    int toCopy = 0;
+
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_AppendLimitedToObj");
+    }
+
+    if (length < 0) {
+	length = (bytes ? strlen(bytes) : 0);
+    }
+    if (length == 0) {
+	return;
+    }
+
+    if (length <= limit) {
+	toCopy = length;
+    } else {
+	if (ellipsis == NULL) {
+	    ellipsis = "...";
+	}
+	toCopy = (bytes == NULL) ? limit
+		: Tcl_UtfPrev(bytes+limit+1-strlen(ellipsis), bytes) - bytes;
+    }
+
+    /*
+     * If objPtr has a valid Unicode rep, then append the Unicode conversion
+     * of "bytes" to the objPtr's Unicode rep, otherwise append "bytes" to
+     * objPtr's string rep.
+     */
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->hasUnicode && stringPtr->numChars > 0) {
+	AppendUtfToUnicodeRep(objPtr, bytes, toCopy);
+    } else {
+	AppendUtfToUtfRep(objPtr, bytes, toCopy);
+    }
+
+    if (length <= limit) {
+	return;
+    }
+
+    stringPtr = GET_STRING(objPtr);
+    if (stringPtr->hasUnicode && stringPtr->numChars > 0) {
+	AppendUtfToUnicodeRep(objPtr, ellipsis, strlen(ellipsis));
+    } else {
+	AppendUtfToUtfRep(objPtr, ellipsis, strlen(ellipsis));
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendToObj --
+ *
+ *	This function appends a sequence of bytes to an object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The bytes at *bytes are appended to the string representation of
+ *	objPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendToObj(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const char *bytes,		/* Points to the bytes to append to the
+				 * object. */
+    int length)			/* The number of bytes to append from "bytes".
+				 * If < 0, then append all bytes up to NUL
+				 * byte. */
+{
+    Tcl_AppendLimitedToObj(objPtr, bytes, length, INT_MAX, NULL);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendUnicodeToObj --
+ *
+ *	This function appends a Unicode string to an object in the most
+ *	efficient manner possible. Length must be >= 0.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Invalidates the string rep and creates a new Unicode string.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendUnicodeToObj(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const Tcl_UniChar *unicode,	/* The unicode string to append to the
+				 * object. */
+    int length)			/* Number of chars in "unicode". */
+{
+    String *stringPtr;
+
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_AppendUnicodeToObj");
+    }
+
+    if (length == 0) {
+	return;
+    }
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    /*
+     * If objPtr has a valid Unicode rep, then append the "unicode" to the
+     * objPtr's Unicode rep, otherwise the UTF conversion of "unicode" to
+     * objPtr's string rep.
+     */
+
+    if (stringPtr->hasUnicode
+#if COMPAT
+		&& stringPtr->numChars > 0
+#endif
+	    ) {
+	AppendUnicodeToUnicodeRep(objPtr, unicode, length);
+    } else {
+	AppendUnicodeToUtfRep(objPtr, unicode, length);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendObjToObj --
+ *
+ *	This function appends the string rep of one object to another.
+ *	"objPtr" cannot be a shared object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The string rep of appendObjPtr is appended to the string
+ *	representation of objPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendObjToObj(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    Tcl_Obj *appendObjPtr)	/* Object to append. */
+{
+    String *stringPtr;
+    int length, numChars, appendNumChars = -1;
+    const char *bytes;
+
+    /*
+     * Special case: second object is standard-empty is fast case. We know
+     * that appending nothing to anything leaves that starting anything...
+     */
+
+    if (appendObjPtr->bytes == tclEmptyStringRep) {
+	return;
+    }
+
+    /*
+     * Handle append of one bytearray object to another as a special case.
+     * Note that we only do this when the objects don't have string reps; if
+     * it did, then appending the byte arrays together could well lose
+     * information; this is a special-case optimization only.
+     */
+
+    if ((TclIsPureByteArray(objPtr) || objPtr->bytes == tclEmptyStringRep)
+	    && TclIsPureByteArray(appendObjPtr)) {
+
+	/*
+	 * You might expect the code here to be
+	 *
+	 *  bytes = Tcl_GetByteArrayFromObj(appendObjPtr, &length);
+	 *  TclAppendBytesToByteArray(objPtr, bytes, length);
+	 *
+	 * and essentially all of the time that would be fine.  However,
+	 * it would run into trouble in the case where objPtr and
+	 * appendObjPtr point to the same thing.  That may never be a
+	 * good idea.  It seems to violate Copy On Write, and we don't
+	 * have any tests for the situation, since making any Tcl commands
+	 * that call Tcl_AppendObjToObj() do that appears impossible
+	 * (They honor Copy On Write!).  For the sake of extensions that
+	 * go off into that realm, though, here's a more complex approach
+	 * that can handle all the cases.
+	 */
+
+	/* Get lengths */
+	int lengthSrc;
+
+	(void) Tcl_GetByteArrayFromObj(objPtr, &length);
+	(void) Tcl_GetByteArrayFromObj(appendObjPtr, &lengthSrc);
+
+	/* Grow buffer enough for the append */
+	TclAppendBytesToByteArray(objPtr, NULL, lengthSrc);
+
+	/* Reset objPtr back to the original value */
+	Tcl_SetByteArrayLength(objPtr, length);
+
+	/*
+	 * Now do the append knowing that buffer growth cannot cause
+	 * any trouble.
+	 */
+
+	TclAppendBytesToByteArray(objPtr,
+		Tcl_GetByteArrayFromObj(appendObjPtr, NULL), lengthSrc);
+	return;
+    }
+
+    /*
+     * Must append as strings.
+     */
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    /*
+     * If objPtr has a valid Unicode rep, then get a Unicode string from
+     * appendObjPtr and append it.
+     */
+
+    if (stringPtr->hasUnicode
+#if COMPAT
+		&& stringPtr->numChars > 0
+#endif
+	    ) {
+	/*
+	 * If appendObjPtr is not of the "String" type, don't convert it.
+	 */
+
+	if (appendObjPtr->typePtr == &tclStringType) {
+	    Tcl_UniChar *unicode =
+		    Tcl_GetUnicodeFromObj(appendObjPtr, &numChars);
+
+	    AppendUnicodeToUnicodeRep(objPtr, unicode, numChars);
+	} else {
+	    bytes = TclGetStringFromObj(appendObjPtr, &length);
+	    AppendUtfToUnicodeRep(objPtr, bytes, length);
+	}
+	return;
+    }
+
+    /*
+     * Append to objPtr's UTF string rep. If we know the number of characters
+     * in both objects before appending, then set the combined number of
+     * characters in the final (appended-to) object.
+     */
+
+    bytes = TclGetStringFromObj(appendObjPtr, &length);
+
+    numChars = stringPtr->numChars;
+    if ((numChars >= 0) && (appendObjPtr->typePtr == &tclStringType)) {
+	String *appendStringPtr = GET_STRING(appendObjPtr);
+	appendNumChars = appendStringPtr->numChars;
+    }
+
+    AppendUtfToUtfRep(objPtr, bytes, length);
+
+    if (numChars >= 0 && appendNumChars >= 0
+#if COMPAT
+		&& appendNumChars == length
+#endif
+	    ) {
+	stringPtr->numChars = numChars + appendNumChars;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AppendUnicodeToUnicodeRep --
+ *
+ *	This function appends the contents of "unicode" to the Unicode rep of
+ *	"objPtr". objPtr must already have a valid Unicode rep.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	objPtr's internal rep is reallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AppendUnicodeToUnicodeRep(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const Tcl_UniChar *unicode,	/* String to append. */
+    int appendNumChars)		/* Number of chars of "unicode" to append. */
+{
+    String *stringPtr;
+    int numChars;
+
+    if (appendNumChars < 0) {
+	appendNumChars = UnicodeLength(unicode);
+    }
+    if (appendNumChars == 0) {
+	return;
+    }
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    /*
+     * If not enough space has been allocated for the unicode rep, reallocate
+     * the internal rep object with additional space. First try to double the
+     * required allocation; if that fails, try a more modest increase. See the
+     * "TCL STRING GROWTH ALGORITHM" comment at the top of this file for an
+     * explanation of this growth algorithm.
+     */
+
+    numChars = stringPtr->numChars + appendNumChars;
+    stringCheckLimits(numChars);
+
+    if (numChars > stringPtr->maxChars) {
+	int offset = -1;
+
+	/*
+	 * Protect against case where unicode points into the existing
+	 * stringPtr->unicode array. Force it to follow any relocations due to
+	 * the reallocs below.
+	 */
+
+	if (unicode && unicode >= stringPtr->unicode
+		&& unicode <= stringPtr->unicode + stringPtr->maxChars) {
+	    offset = unicode - stringPtr->unicode;
+	}
+
+	GrowUnicodeBuffer(objPtr, numChars);
+	stringPtr = GET_STRING(objPtr);
+
+	/*
+	 * Relocate unicode if needed; see above.
+	 */
+
+	if (offset >= 0) {
+	    unicode = stringPtr->unicode + offset;
+	}
+    }
+
+    /*
+     * Copy the new string onto the end of the old string, then add the
+     * trailing null.
+     */
+
+    if (unicode) {
+	memmove(stringPtr->unicode + stringPtr->numChars, unicode,
+		appendNumChars * sizeof(Tcl_UniChar));
+    }
+    stringPtr->unicode[numChars] = 0;
+    stringPtr->numChars = numChars;
+    stringPtr->allocated = 0;
+
+    TclInvalidateStringRep(objPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AppendUnicodeToUtfRep --
+ *
+ *	This function converts the contents of "unicode" to UTF and appends
+ *	the UTF to the string rep of "objPtr".
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	objPtr's internal rep is reallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AppendUnicodeToUtfRep(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const Tcl_UniChar *unicode,	/* String to convert to UTF. */
+    int numChars)		/* Number of chars of "unicode" to convert. */
+{
+    String *stringPtr = GET_STRING(objPtr);
+
+    numChars = ExtendStringRepWithUnicode(objPtr, unicode, numChars);
+
+    if (stringPtr->numChars != -1) {
+	stringPtr->numChars += numChars;
+    }
+
+#if COMPAT
+    /*
+     * Invalidate the unicode rep.
+     */
+
+    stringPtr->hasUnicode = 0;
+#endif
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AppendUtfToUnicodeRep --
+ *
+ *	This function converts the contents of "bytes" to Unicode and appends
+ *	the Unicode to the Unicode rep of "objPtr". objPtr must already have a
+ *	valid Unicode rep. numBytes must be non-negative.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	objPtr's internal rep is reallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AppendUtfToUnicodeRep(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const char *bytes,		/* String to convert to Unicode. */
+    int numBytes)		/* Number of bytes of "bytes" to convert. */
+{
+    String *stringPtr;
+
+    if (numBytes == 0) {
+	return;
+    }
+
+    ExtendUnicodeRepWithString(objPtr, bytes, numBytes, -1);
+    TclInvalidateStringRep(objPtr);
+    stringPtr = GET_STRING(objPtr);
+    stringPtr->allocated = 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AppendUtfToUtfRep --
+ *
+ *	This function appends "numBytes" bytes of "bytes" to the UTF string
+ *	rep of "objPtr". objPtr must already have a valid String rep.
+ *	numBytes must be non-negative.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	objPtr's internal rep is reallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AppendUtfToUtfRep(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    const char *bytes,		/* String to append. */
+    int numBytes)		/* Number of bytes of "bytes" to append. */
+{
+    String *stringPtr;
+    int newLength, oldLength;
+
+    if (numBytes == 0) {
+	return;
+    }
+
+    /*
+     * Copy the new string onto the end of the old string, then add the
+     * trailing null.
+     */
+
+    if (objPtr->bytes == NULL) {
+	objPtr->length = 0;
+    }
+    oldLength = objPtr->length;
+    newLength = numBytes + oldLength;
+    if (newLength < 0) {
+	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
+    }
+
+    stringPtr = GET_STRING(objPtr);
+    if (newLength > stringPtr->allocated) {
+	int offset = -1;
+
+	/*
+	 * Protect against case where unicode points into the existing
+	 * stringPtr->unicode array. Force it to follow any relocations due to
+	 * the reallocs below.
+	 */
+
+	if (bytes && bytes >= objPtr->bytes
+		&& bytes <= objPtr->bytes + objPtr->length) {
+	    offset = bytes - objPtr->bytes;
+	}
+
+	/*
+	 * TODO: consider passing flag=1: no overalloc on first append. This
+	 * would make test stringObj-8.1 fail.
+	 */
+
+	GrowStringBuffer(objPtr, newLength, 0);
+
+	/*
+	 * Relocate bytes if needed; see above.
+	 */
+
+	if (offset >= 0) {
+	    bytes = objPtr->bytes + offset;
+	}
+    }
+
+    /*
+     * Invalidate the unicode data.
+     */
+
+    stringPtr->numChars = -1;
+    stringPtr->hasUnicode = 0;
+
+    if (bytes) {
+	memmove(objPtr->bytes + oldLength, bytes, numBytes);
+    }
+    objPtr->bytes[newLength] = 0;
+    objPtr->length = newLength;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendStringsToObjVA --
+ *
+ *	This function appends one or more null-terminated strings to an
+ *	object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The contents of all the string arguments are appended to the string
+ *	representation of objPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendStringsToObjVA(
+    Tcl_Obj *objPtr,		/* Points to the object to append to. */
+    va_list argList)		/* Variable argument list. */
+{
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_AppendStringsToObj");
+    }
+
+    while (1) {
+	const char *bytes = va_arg(argList, char *);
+
+	if (bytes == NULL) {
+	    break;
+	}
+	Tcl_AppendToObj(objPtr, bytes, -1);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendStringsToObj --
+ *
+ *	This function appends one or more null-terminated strings to an
+ *	object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The contents of all the string arguments are appended to the string
+ *	representation of objPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendStringsToObj(
+    Tcl_Obj *objPtr,
+    ...)
+{
+    va_list argList;
+
+    va_start(argList, objPtr);
+    Tcl_AppendStringsToObjVA(objPtr, argList);
+    va_end(argList);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AppendFormatToObj --
+ *
+ *	This function appends a list of Tcl_Obj's to a Tcl_Obj according to
+ *	the formatting instructions embedded in the format string. The
+ *	formatting instructions are inspired by sprintf(). Returns TCL_OK when
+ *	successful. If there's an error in the arguments, TCL_ERROR is
+ *	returned, and an error message is written to the interp, if non-NULL.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_AppendFormatToObj(
+    Tcl_Interp *interp,
+    Tcl_Obj *appendObj,
+    const char *format,
+    int objc,
+    Tcl_Obj *const objv[])
+{
+    const char *span = format, *msg, *errCode;
+    int numBytes = 0, objIndex = 0, gotXpg = 0, gotSequential = 0;
+    int originalLength, limit;
+    static const char *mixedXPG =
+	    "cannot mix \"%\" and \"%n$\" conversion specifiers";
+    static const char *const badIndex[2] = {
+	"not enough arguments for all format specifiers",
+	"\"%n$\" argument index out of range"
+    };
+    static const char *overflow = "max size for a Tcl value exceeded";
+
+    if (Tcl_IsShared(appendObj)) {
+	Tcl_Panic("%s called with shared object", "Tcl_AppendFormatToObj");
+    }
+    TclGetStringFromObj(appendObj, &originalLength);
+    limit = INT_MAX - originalLength;
+
+    /*
+     * Format string is NUL-terminated.
+     */
+
+    while (*format != '\0') {
+	char *end;
+	int gotMinus, gotHash, gotZero, gotSpace, gotPlus, sawFlag;
+	int width, gotPrecision, precision, useShort, useWide, useBig;
+	int newXpg, numChars, allocSegment = 0, segmentLimit, segmentNumBytes;
+	Tcl_Obj *segment;
+	Tcl_UniChar ch;
+	int step = Tcl_UtfToUniChar(format, &ch);
+
+	format += step;
+	if (ch != '%') {
+	    numBytes += step;
+	    continue;
+	}
+	if (numBytes) {
+	    if (numBytes > limit) {
+		msg = overflow;
+		errCode = "OVERFLOW";
+		goto errorMsg;
+	    }
+	    Tcl_AppendToObj(appendObj, span, numBytes);
+	    limit -= numBytes;
+	    numBytes = 0;
+	}
+
+	/*
+	 * Saw a % : process the format specifier.
+	 *
+	 * Step 0. Handle special case of escaped format marker (i.e., %%).
+	 */
+
+	step = Tcl_UtfToUniChar(format, &ch);
+	if (ch == '%') {
+	    span = format;
+	    numBytes = step;
+	    format += step;
+	    continue;
+	}
+
+	/*
+	 * Step 1. XPG3 position specifier
+	 */
+
+	newXpg = 0;
+	if (isdigit(UCHAR(ch))) {
+	    int position = strtoul(format, &end, 10);
+
+	    if (*end == '$') {
+		newXpg = 1;
+		objIndex = position - 1;
+		format = end + 1;
+		step = Tcl_UtfToUniChar(format, &ch);
+	    }
+	}
+	if (newXpg) {
+	    if (gotSequential) {
+		msg = mixedXPG;
+		errCode = "MIXEDSPECTYPES";
+		goto errorMsg;
+	    }
+	    gotXpg = 1;
+	} else {
+	    if (gotXpg) {
+		msg = mixedXPG;
+		errCode = "MIXEDSPECTYPES";
+		goto errorMsg;
+	    }
+	    gotSequential = 1;
+	}
+	if ((objIndex < 0) || (objIndex >= objc)) {
+	    msg = badIndex[gotXpg];
+	    errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
+	    goto errorMsg;
+	}
+
+	/*
+	 * Step 2. Set of flags.
+	 */
+
+	gotMinus = gotHash = gotZero = gotSpace = gotPlus = 0;
+	sawFlag = 1;
+	do {
+	    switch (ch) {
+	    case '-':
+		gotMinus = 1;
+		break;
+	    case '#':
+		gotHash = 1;
+		break;
+	    case '0':
+		gotZero = 1;
+		break;
+	    case ' ':
+		gotSpace = 1;
+		break;
+	    case '+':
+		gotPlus = 1;
+		break;
+	    default:
+		sawFlag = 0;
+	    }
+	    if (sawFlag) {
+		format += step;
+		step = Tcl_UtfToUniChar(format, &ch);
+	    }
+	} while (sawFlag);
+
+	/*
+	 * Step 3. Minimum field width.
+	 */
+
+	width = 0;
+	if (isdigit(UCHAR(ch))) {
+	    width = strtoul(format, &end, 10);
+	    format = end;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	} else if (ch == '*') {
+	    if (objIndex >= objc - 1) {
+		msg = badIndex[gotXpg];
+		errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
+		goto errorMsg;
+	    }
+	    if (TclGetIntFromObj(interp, objv[objIndex], &width) != TCL_OK) {
+		goto error;
+	    }
+	    if (width < 0) {
+		width = -width;
+		gotMinus = 1;
+	    }
+	    objIndex++;
+	    format += step;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	}
+	if (width > limit) {
+	    msg = overflow;
+	    errCode = "OVERFLOW";
+	    goto errorMsg;
+	}
+
+	/*
+	 * Step 4. Precision.
+	 */
+
+	gotPrecision = precision = 0;
+	if (ch == '.') {
+	    gotPrecision = 1;
+	    format += step;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	}
+	if (isdigit(UCHAR(ch))) {
+	    precision = strtoul(format, &end, 10);
+	    format = end;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	} else if (ch == '*') {
+	    if (objIndex >= objc - 1) {
+		msg = badIndex[gotXpg];
+		errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
+		goto errorMsg;
+	    }
+	    if (TclGetIntFromObj(interp, objv[objIndex], &precision)
+		    != TCL_OK) {
+		goto error;
+	    }
+
+	    /*
+	     * TODO: Check this truncation logic.
+	     */
+
+	    if (precision < 0) {
+		precision = 0;
+	    }
+	    objIndex++;
+	    format += step;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	}
+
+	/*
+	 * Step 5. Length modifier.
+	 */
+
+	useShort = useWide = useBig = 0;
+	if (ch == 'h') {
+	    useShort = 1;
+	    format += step;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	} else if (ch == 'l') {
+	    format += step;
+	    step = Tcl_UtfToUniChar(format, &ch);
+	    if (ch == 'l') {
+		useBig = 1;
+		format += step;
+		step = Tcl_UtfToUniChar(format, &ch);
+#ifndef TCL_WIDE_INT_IS_LONG
+	    } else {
+		useWide = 1;
+#endif
+	    }
+	}
+
+	format += step;
+	span = format;
+
+	/*
+	 * Step 6. The actual conversion character.
+	 */
+
+	segment = objv[objIndex];
+	numChars = -1;
+	if (ch == 'i') {
+	    ch = 'd';
+	}
+	switch (ch) {
+	case '\0':
+	    msg = "format string ended in middle of field specifier";
+	    errCode = "INCOMPLETE";
+	    goto errorMsg;
+	case 's':
+	    if (gotPrecision) {
+		numChars = Tcl_GetCharLength(segment);
+		if (precision < numChars) {
+		    segment = Tcl_GetRange(segment, 0, precision - 1);
+		    numChars = precision;
+		    Tcl_IncrRefCount(segment);
+		    allocSegment = 1;
+		}
+	    }
+	    break;
+	case 'c': {
+	    char buf[TCL_UTF_MAX];
+	    int code, length;
+
+	    if (TclGetIntFromObj(interp, segment, &code) != TCL_OK) {
+		goto error;
+	    }
+	    length = Tcl_UniCharToUtf(code, buf);
+	    segment = Tcl_NewStringObj(buf, length);
+	    Tcl_IncrRefCount(segment);
+	    allocSegment = 1;
+	    break;
+	}
+
+	case 'u':
+	    if (useBig) {
+		msg = "unsigned bignum format is invalid";
+		errCode = "BADUNSIGNED";
+		goto errorMsg;
+	    }
+	case 'd':
+	case 'o':
+	case 'x':
+	case 'X':
+	case 'b': {
+	    short s = 0;	/* Silence compiler warning; only defined and
+				 * used when useShort is true. */
+	    long l;
+	    Tcl_WideInt w;
+	    mp_int big;
+	    int toAppend, isNegative = 0;
+
+	    if (useBig) {
+		if (Tcl_GetBignumFromObj(interp, segment, &big) != TCL_OK) {
+		    goto error;
+		}
+		isNegative = (mp_cmp_d(&big, 0) == MP_LT);
+	    } else if (useWide) {
+		if (Tcl_GetWideIntFromObj(NULL, segment, &w) != TCL_OK) {
+		    Tcl_Obj *objPtr;
+
+		    if (Tcl_GetBignumFromObj(interp,segment,&big) != TCL_OK) {
+			goto error;
+		    }
+		    mp_mod_2d(&big, (int) CHAR_BIT*sizeof(Tcl_WideInt), &big);
+		    objPtr = Tcl_NewBignumObj(&big);
+		    Tcl_IncrRefCount(objPtr);
+		    Tcl_GetWideIntFromObj(NULL, objPtr, &w);
+		    Tcl_DecrRefCount(objPtr);
+		}
+		isNegative = (w < (Tcl_WideInt) 0);
+	    } else if (TclGetLongFromObj(NULL, segment, &l) != TCL_OK) {
+		if (Tcl_GetWideIntFromObj(NULL, segment, &w) != TCL_OK) {
+		    Tcl_Obj *objPtr;
+
+		    if (Tcl_GetBignumFromObj(interp,segment,&big) != TCL_OK) {
+			goto error;
+		    }
+		    mp_mod_2d(&big, (int) CHAR_BIT * sizeof(long), &big);
+		    objPtr = Tcl_NewBignumObj(&big);
+		    Tcl_IncrRefCount(objPtr);
+		    TclGetLongFromObj(NULL, objPtr, &l);
+		    Tcl_DecrRefCount(objPtr);
+		} else {
+		    l = Tcl_WideAsLong(w);
+		}
+		if (useShort) {
+		    s = (short) l;
+		    isNegative = (s < (short) 0);
+		} else {
+		    isNegative = (l < (long) 0);
+		}
+	    } else if (useShort) {
+		s = (short) l;
+		isNegative = (s < (short) 0);
+	    } else {
+		isNegative = (l < (long) 0);
+	    }
+
+	    segment = Tcl_NewObj();
+	    allocSegment = 1;
+	    segmentLimit = INT_MAX;
+	    Tcl_IncrRefCount(segment);
+
+	    if ((isNegative || gotPlus || gotSpace) && (useBig || ch=='d')) {
+		Tcl_AppendToObj(segment,
+			(isNegative ? "-" : gotPlus ? "+" : " "), 1);
+		segmentLimit -= 1;
+	    }
+
+	    if (gotHash) {
+		switch (ch) {
+		case 'o':
+		    Tcl_AppendToObj(segment, "0", 1);
+		    segmentLimit -= 1;
+		    precision--;
+		    break;
+		case 'x':
+		case 'X':
+		    Tcl_AppendToObj(segment, "0x", 2);
+		    segmentLimit -= 2;
+		    break;
+		case 'b':
+		    Tcl_AppendToObj(segment, "0b", 2);
+		    segmentLimit -= 2;
+		    break;
+		}
+	    }
+
+	    switch (ch) {
+	    case 'd': {
+		int length;
+		Tcl_Obj *pure;
+		const char *bytes;
+
+		if (useShort) {
+		    pure = Tcl_NewIntObj((int) s);
+		} else if (useWide) {
+		    pure = Tcl_NewWideIntObj(w);
+		} else if (useBig) {
+		    pure = Tcl_NewBignumObj(&big);
+		} else {
+		    pure = Tcl_NewLongObj(l);
+		}
+		Tcl_IncrRefCount(pure);
+		bytes = TclGetStringFromObj(pure, &length);
+
+		/*
+		 * Already did the sign above.
+		 */
+
+		if (*bytes == '-') {
+		    length--;
+		    bytes++;
+		}
+		toAppend = length;
+
+		/*
+		 * Canonical decimal string reps for integers are composed
+		 * entirely of one-byte encoded characters, so "length" is the
+		 * number of chars.
+		 */
+
+		if (gotPrecision) {
+		    if (length < precision) {
+			segmentLimit -= precision - length;
+		    }
+		    while (length < precision) {
+			Tcl_AppendToObj(segment, "0", 1);
+			length++;
+		    }
+		    gotZero = 0;
+		}
+		if (gotZero) {
+		    length += Tcl_GetCharLength(segment);
+		    if (length < width) {
+			segmentLimit -= width - length;
+		    }
+		    while (length < width) {
+			Tcl_AppendToObj(segment, "0", 1);
+			length++;
+		    }
+		}
+		if (toAppend > segmentLimit) {
+		    msg = overflow;
+		    errCode = "OVERFLOW";
+		    goto errorMsg;
+		}
+		Tcl_AppendToObj(segment, bytes, toAppend);
+		Tcl_DecrRefCount(pure);
+		break;
+	    }
+
+	    case 'u':
+	    case 'o':
+	    case 'x':
+	    case 'X':
+	    case 'b': {
+		Tcl_WideUInt bits = (Tcl_WideUInt) 0;
+		Tcl_WideInt numDigits = (Tcl_WideInt) 0;
+		int length, numBits = 4, base = 16, index = 0, shift = 0;
+		Tcl_Obj *pure;
+		char *bytes;
+
+		if (ch == 'u') {
+		    base = 10;
+		} else if (ch == 'o') {
+		    base = 8;
+		    numBits = 3;
+		} else if (ch == 'b') {
+		    base = 2;
+		    numBits = 1;
+		}
+		if (useShort) {
+		    unsigned short us = (unsigned short) s;
+
+		    bits = (Tcl_WideUInt) us;
+		    while (us) {
+			numDigits++;
+			us /= base;
+		    }
+		} else if (useWide) {
+		    Tcl_WideUInt uw = (Tcl_WideUInt) w;
+
+		    bits = uw;
+		    while (uw) {
+			numDigits++;
+			uw /= base;
+		    }
+		} else if (useBig && big.used) {
+		    int leftover = (big.used * DIGIT_BIT) % numBits;
+		    mp_digit mask = (~(mp_digit)0) << (DIGIT_BIT-leftover);
+
+		    numDigits = 1 +
+			    (((Tcl_WideInt) big.used * DIGIT_BIT) / numBits);
+		    while ((mask & big.dp[big.used-1]) == 0) {
+			numDigits--;
+			mask >>= numBits;
+		    }
+		    if (numDigits > INT_MAX) {
+			msg = overflow;
+			errCode = "OVERFLOW";
+			goto errorMsg;
+		    }
+		} else if (!useBig) {
+		    unsigned long ul = (unsigned long) l;
+
+		    bits = (Tcl_WideUInt) ul;
+		    while (ul) {
+			numDigits++;
+			ul /= base;
+		    }
+		}
+
+		/*
+		 * Need to be sure zero becomes "0", not "".
+		 */
+
+		if ((numDigits == 0) && !((ch == 'o') && gotHash)) {
+		    numDigits = 1;
+		}
+		pure = Tcl_NewObj();
+		Tcl_SetObjLength(pure, (int) numDigits);
+		bytes = TclGetString(pure);
+		toAppend = length = (int) numDigits;
+		while (numDigits--) {
+		    int digitOffset;
+
+		    if (useBig && big.used) {
+			if (index < big.used && (size_t) shift <
+				CHAR_BIT*sizeof(Tcl_WideUInt) - DIGIT_BIT) {
+			    bits |= ((Tcl_WideUInt) big.dp[index++]) << shift;
+			    shift += DIGIT_BIT;
+			}
+			shift -= numBits;
+		    }
+		    digitOffset = (int) (bits % base);
+		    if (digitOffset > 9) {
+			bytes[numDigits] = 'a' + digitOffset - 10;
+		    } else {
+			bytes[numDigits] = '0' + digitOffset;
+		    }
+		    bits /= base;
+		}
+		if (useBig) {
+		    mp_clear(&big);
+		}
+		if (gotPrecision) {
+		    if (length < precision) {
+			segmentLimit -= precision - length;
+		    }
+		    while (length < precision) {
+			Tcl_AppendToObj(segment, "0", 1);
+			length++;
+		    }
+		    gotZero = 0;
+		}
+		if (gotZero) {
+		    length += Tcl_GetCharLength(segment);
+		    if (length < width) {
+			segmentLimit -= width - length;
+		    }
+		    while (length < width) {
+			Tcl_AppendToObj(segment, "0", 1);
+			length++;
+		    }
+		}
+		if (toAppend > segmentLimit) {
+		    msg = overflow;
+		    errCode = "OVERFLOW";
+		    goto errorMsg;
+		}
+		Tcl_AppendObjToObj(segment, pure);
+		Tcl_DecrRefCount(pure);
+		break;
+	    }
+
+	    }
+	    break;
+	}
+
+	case 'e':
+	case 'E':
+	case 'f':
+	case 'g':
+	case 'G': {
+#define MAX_FLOAT_SIZE 320
+	    char spec[2*TCL_INTEGER_SPACE + 9], *p = spec;
+	    double d;
+	    int length = MAX_FLOAT_SIZE;
+	    char *bytes;
+
+	    if (Tcl_GetDoubleFromObj(interp, segment, &d) != TCL_OK) {
+		/* TODO: Figure out ACCEPT_NAN here */
+		goto error;
+	    }
+	    *p++ = '%';
+	    if (gotMinus) {
+		*p++ = '-';
+	    }
+	    if (gotHash) {
+		*p++ = '#';
+	    }
+	    if (gotZero) {
+		*p++ = '0';
+	    }
+	    if (gotSpace) {
+		*p++ = ' ';
+	    }
+	    if (gotPlus) {
+		*p++ = '+';
+	    }
+	    if (width) {
+		p += sprintf(p, "%d", width);
+		if (width > length) {
+		    length = width;
+		}
+	    }
+	    if (gotPrecision) {
+		*p++ = '.';
+		p += sprintf(p, "%d", precision);
+		if (precision > INT_MAX - length) {
+		    msg = overflow;
+		    errCode = "OVERFLOW";
+		    goto errorMsg;
+		}
+		length += precision;
+	    }
+
+	    /*
+	     * Don't pass length modifiers!
+	     */
+
+	    *p++ = (char) ch;
+	    *p = '\0';
+
+	    segment = Tcl_NewObj();
+	    allocSegment = 1;
+	    if (!Tcl_AttemptSetObjLength(segment, length)) {
+		msg = overflow;
+		errCode = "OVERFLOW";
+		goto errorMsg;
+	    }
+	    bytes = TclGetString(segment);
+	    if (!Tcl_AttemptSetObjLength(segment, sprintf(bytes, spec, d))) {
+		msg = overflow;
+		errCode = "OVERFLOW";
+		goto errorMsg;
+	    }
+	    break;
+	}
+	default:
+	    if (interp != NULL) {
+		Tcl_SetObjResult(interp,
+			Tcl_ObjPrintf("bad field specifier \"%c\"", ch));
+		Tcl_SetErrorCode(interp, "TCL", "FORMAT", "BADTYPE", NULL);
+	    }
+	    goto error;
+	}
+
+	switch (ch) {
+	case 'E':
+	case 'G':
+	case 'X': {
+	    Tcl_SetObjLength(segment, Tcl_UtfToUpper(TclGetString(segment)));
+	}
+	}
+
+	if (width>0 && numChars<0) {
+	    numChars = Tcl_GetCharLength(segment);
+	}
+	if (!gotMinus && width>0) {
+	    if (numChars < width) {
+		limit -= width - numChars;
+	    }
+	    while (numChars < width) {
+		Tcl_AppendToObj(appendObj, (gotZero ? "0" : " "), 1);
+		numChars++;
+	    }
+	}
+
+	Tcl_GetStringFromObj(segment, &segmentNumBytes);
+	if (segmentNumBytes > limit) {
+	    if (allocSegment) {
+		Tcl_DecrRefCount(segment);
+	    }
+	    msg = overflow;
+	    errCode = "OVERFLOW";
+	    goto errorMsg;
+	}
+	Tcl_AppendObjToObj(appendObj, segment);
+	limit -= segmentNumBytes;
+	if (allocSegment) {
+	    Tcl_DecrRefCount(segment);
+	}
+	if (width > 0) {
+	    if (numChars < width) {
+		limit -= width-numChars;
+	    }
+	    while (numChars < width) {
+		Tcl_AppendToObj(appendObj, (gotZero ? "0" : " "), 1);
+		numChars++;
+	    }
+	}
+
+	objIndex += gotSequential;
+    }
+    if (numBytes) {
+	if (numBytes > limit) {
+	    msg = overflow;
+	    errCode = "OVERFLOW";
+	    goto errorMsg;
+	}
+	Tcl_AppendToObj(appendObj, span, numBytes);
+	limit -= numBytes;
+	numBytes = 0;
+    }
+
+    return TCL_OK;
+
+  errorMsg:
+    if (interp != NULL) {
+	Tcl_SetObjResult(interp, Tcl_NewStringObj(msg, -1));
+	Tcl_SetErrorCode(interp, "TCL", "FORMAT", errCode, NULL);
+    }
+  error:
+    Tcl_SetObjLength(appendObj, originalLength);
+    return TCL_ERROR;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * Tcl_Format--
+ *
+ * Results:
+ *	A refcount zero Tcl_Obj.
+ *
+ * Side effects:
+ *	None.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_Format(
+    Tcl_Interp *interp,
+    const char *format,
+    int objc,
+    Tcl_Obj *const objv[])
+{
+    int result;
+    Tcl_Obj *objPtr = Tcl_NewObj();
+
+    result = Tcl_AppendFormatToObj(interp, objPtr, format, objc, objv);
+    if (result != TCL_OK) {
+	Tcl_DecrRefCount(objPtr);
+	return NULL;
+    }
+    return objPtr;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * AppendPrintfToObjVA --
+ *
+ * Results:
+ *
+ * Side effects:
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static void
+AppendPrintfToObjVA(
+    Tcl_Obj *objPtr,
+    const char *format,
+    va_list argList)
+{
+    int code, objc;
+    Tcl_Obj **objv, *list = Tcl_NewObj();
+    const char *p;
+
+    p = format;
+    Tcl_IncrRefCount(list);
+    while (*p != '\0') {
+	int size = 0, seekingConversion = 1, gotPrecision = 0;
+	int lastNum = -1;
+
+	if (*p++ != '%') {
+	    continue;
+	}
+	if (*p == '%') {
+	    p++;
+	    continue;
+	}
+	do {
+	    switch (*p) {
+	    case '\0':
+		seekingConversion = 0;
+		break;
+	    case 's': {
+		const char *q, *end, *bytes = va_arg(argList, char *);
+		seekingConversion = 0;
+
+		/*
+		 * The buffer to copy characters from starts at bytes and ends
+		 * at either the first NUL byte, or after lastNum bytes, when
+		 * caller has indicated a limit.
+		 */
+
+		end = bytes;
+		while ((!gotPrecision || lastNum--) && (*end != '\0')) {
+		    end++;
+		}
+
+		/*
+		 * Within that buffer, we trim both ends if needed so that we
+		 * copy only whole characters, and avoid copying any partial
+		 * multi-byte characters.
+		 */
+
+		q = Tcl_UtfPrev(end, bytes);
+		if (!Tcl_UtfCharComplete(q, (int)(end - q))) {
+		    end = q;
+		}
+
+		q = bytes + TCL_UTF_MAX;
+		while ((bytes < end) && (bytes < q)
+			&& ((*bytes & 0xC0) == 0x80)) {
+		    bytes++;
+		}
+
+		Tcl_ListObjAppendElement(NULL, list,
+			Tcl_NewStringObj(bytes , (int)(end - bytes)));
+
+		break;
+	    }
+	    case 'c':
+	    case 'i':
+	    case 'u':
+	    case 'd':
+	    case 'o':
+	    case 'x':
+	    case 'X':
+		seekingConversion = 0;
+		switch (size) {
+		case -1:
+		case 0:
+		    Tcl_ListObjAppendElement(NULL, list, Tcl_NewLongObj(
+			    (long) va_arg(argList, int)));
+		    break;
+		case 1:
+		    Tcl_ListObjAppendElement(NULL, list, Tcl_NewLongObj(
+			    va_arg(argList, long)));
+		    break;
+		}
+		break;
+	    case 'e':
+	    case 'E':
+	    case 'f':
+	    case 'g':
+	    case 'G':
+		Tcl_ListObjAppendElement(NULL, list, Tcl_NewDoubleObj(
+			va_arg(argList, double)));
+		seekingConversion = 0;
+		break;
+	    case '*':
+		lastNum = (int) va_arg(argList, int);
+		Tcl_ListObjAppendElement(NULL, list, Tcl_NewIntObj(lastNum));
+		p++;
+		break;
+	    case '0': case '1': case '2': case '3': case '4':
+	    case '5': case '6': case '7': case '8': case '9': {
+		char *end;
+
+		lastNum = (int) strtoul(p, &end, 10);
+		p = end;
+		break;
+	    }
+	    case '.':
+		gotPrecision = 1;
+		p++;
+		break;
+	    /* TODO: support for wide (and bignum?) arguments */
+	    case 'l':
+		size = 1;
+		p++;
+		break;
+	    case 'h':
+		size = -1;
+	    default:
+		p++;
+	    }
+	} while (seekingConversion);
+    }
+    TclListObjGetElements(NULL, list, &objc, &objv);
+    code = Tcl_AppendFormatToObj(NULL, objPtr, format, objc, objv);
+    if (code != TCL_OK) {
+	Tcl_AppendPrintfToObj(objPtr,
+		"Unable to format \"%s\" with supplied arguments: %s",
+		format, Tcl_GetString(list));
+    }
+    Tcl_DecrRefCount(list);
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * Tcl_AppendPrintfToObj --
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+void
+Tcl_AppendPrintfToObj(
+    Tcl_Obj *objPtr,
+    const char *format,
+    ...)
+{
+    va_list argList;
+
+    va_start(argList, format);
+    AppendPrintfToObjVA(objPtr, format, argList);
+    va_end(argList);
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * Tcl_ObjPrintf --
+ *
+ * Results:
+ *	A refcount zero Tcl_Obj.
+ *
+ * Side effects:
+ *	None.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_ObjPrintf(
+    const char *format,
+    ...)
+{
+    va_list argList;
+    Tcl_Obj *objPtr = Tcl_NewObj();
+
+    va_start(argList, format);
+    AppendPrintfToObjVA(objPtr, format, argList);
+    va_end(argList);
+    return objPtr;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * TclGetStringStorage --
+ *
+ *	Returns the string storage space of a Tcl_Obj.
+ *
+ * Results:
+ *	The pointer value objPtr->bytes is returned and the number of bytes
+ *	allocated there is written to *sizePtr (if known).
+ *
+ * Side effects:
+ *	May set objPtr->bytes.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+char *
+TclGetStringStorage(
+    Tcl_Obj *objPtr,
+    unsigned int *sizePtr)
+{
+    String *stringPtr;
+
+    if (objPtr->typePtr != &tclStringType || objPtr->bytes == NULL) {
+	return TclGetStringFromObj(objPtr, (int *)sizePtr);
+    }
+
+    stringPtr = GET_STRING(objPtr);
+    *sizePtr = stringPtr->allocated;
+    return objPtr->bytes;
+}
+/*
+ *---------------------------------------------------------------------------
+ *
+ * TclStringObjReverse --
+ *
+ *	Implements the [string reverse] operation.
+ *
+ * Results:
+ *	An unshared Tcl value which is the [string reverse] of the argument
+ *	supplied. When sharing rules permit, the returned value might be the
+ *	argument with modifications done in place.
+ *
+ * Side effects:
+ *	May allocate a new Tcl_Obj.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static void
+ReverseBytes(
+    unsigned char *to,		/* Copy bytes into here... */
+    unsigned char *from,	/* ...from here... */
+    int count)		/* Until this many are copied, */
+				/* reversing as you go. */
+{
+    unsigned char *src = from + count;
+    if (to == from) {
+	/* Reversing in place */
+	while (--src > to) {
+	    unsigned char c = *src;
+	    *src = *to;
+	    *to++ = c;
+	}
+    }  else {
+	while (--src >= from) {
+	    *to++ = *src;
+	}
+    }
+}
+
+Tcl_Obj *
+TclStringObjReverse(
+    Tcl_Obj *objPtr)
+{
+    String *stringPtr;
+    Tcl_UniChar ch;
+
+    if (TclIsPureByteArray(objPtr)) {
+	int numBytes;
+	unsigned char *from = Tcl_GetByteArrayFromObj(objPtr, &numBytes);
+
+	if (Tcl_IsShared(objPtr)) {
+	    objPtr = Tcl_NewByteArrayObj(NULL, numBytes);
+	}
+	ReverseBytes(Tcl_GetByteArrayFromObj(objPtr, NULL), from, numBytes);
+	return objPtr;
+    }
+
+    SetStringFromAny(NULL, objPtr);
+    stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->hasUnicode) {
+	Tcl_UniChar *from = Tcl_GetUnicode(objPtr);
+	Tcl_UniChar *src = from + stringPtr->numChars;
+
+	if (Tcl_IsShared(objPtr)) {
+	    Tcl_UniChar *to;
+
+	    /*
+	     * Create a non-empty, pure unicode value, so we can coax
+	     * Tcl_SetObjLength into growing the unicode rep buffer.
+	     */
+
+	    ch = 0;
+	    objPtr = Tcl_NewUnicodeObj(&ch, 1);
+	    Tcl_SetObjLength(objPtr, stringPtr->numChars);
+	    to = Tcl_GetUnicode(objPtr);
+	    while (--src >= from) {
+		*to++ = *src;
+	    }
+	} else {
+	    /* Reversing in place */
+	    while (--src > from) {
+		ch = *src;
+		*src = *from;
+		*from++ = ch;
+	    }
+	}
+    }
+
+    if (objPtr->bytes) {
+	int numChars = stringPtr->numChars;
+	int numBytes = objPtr->length;
+	char *to, *from = objPtr->bytes;
+
+	if (Tcl_IsShared(objPtr)) {
+	    objPtr = Tcl_NewObj();
+	    Tcl_SetObjLength(objPtr, numBytes);
+	}
+	to = objPtr->bytes;
+
+	if (numChars < numBytes) {
+	    /*
+	     * Either numChars == -1 and we don't know how many chars are
+	     * represented by objPtr->bytes and we need Pass 1 just in case,
+	     * or numChars >= 0 and we know we have fewer chars than bytes,
+	     * so we know there's a multibyte character needing Pass 1.
+	     *
+	     * Pass 1. Reverse the bytes of each multi-byte character.
+	     */
+	    int charCount = 0;
+	    int bytesLeft = numBytes;
+
+	    while (bytesLeft) {
+		/*
+		 * NOTE: We know that the from buffer is NUL-terminated.
+		 * It's part of the contract for objPtr->bytes values.
+		 * Thus, we can skip calling Tcl_UtfCharComplete() here.
+		 */
+		int bytesInChar = Tcl_UtfToUniChar(from, &ch);
+
+		ReverseBytes((unsigned char *)to, (unsigned char *)from,
+			bytesInChar);
+		to += bytesInChar;
+		from += bytesInChar;
+		bytesLeft -= bytesInChar;
+		charCount++;
+	    }
+
+	    from = to = objPtr->bytes;
+	    stringPtr->numChars = charCount;
+	}
+	/* Pass 2. Reverse all the bytes. */
+	ReverseBytes((unsigned char *)to, (unsigned char *)from, numBytes);
+    }
+
+    return objPtr;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * FillUnicodeRep --
+ *
+ *	Populate the Unicode internal rep with the Unicode form of its string
+ *	rep. The object must alread have a "String" internal rep.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Reallocates the String internal rep.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static void
+FillUnicodeRep(
+    Tcl_Obj *objPtr)		/* The object in which to fill the unicode
+				 * rep. */
+{
+    String *stringPtr = GET_STRING(objPtr);
+
+    ExtendUnicodeRepWithString(objPtr, objPtr->bytes, objPtr->length,
+	    stringPtr->numChars);
+}
+
+static void
+ExtendUnicodeRepWithString(
+    Tcl_Obj *objPtr,
+    const char *bytes,
+    int numBytes,
+    int numAppendChars)
+{
+    String *stringPtr = GET_STRING(objPtr);
+    int needed, numOrigChars = 0;
+    Tcl_UniChar *dst;
+
+    if (stringPtr->hasUnicode) {
+	numOrigChars = stringPtr->numChars;
+    }
+    if (numAppendChars == -1) {
+	TclNumUtfChars(numAppendChars, bytes, numBytes);
+    }
+    needed = numOrigChars + numAppendChars;
+    stringCheckLimits(needed);
+
+    if (needed > stringPtr->maxChars) {
+	GrowUnicodeBuffer(objPtr, needed);
+	stringPtr = GET_STRING(objPtr);
+    }
+
+    stringPtr->hasUnicode = 1;
+    if (bytes) {
+	stringPtr->numChars = needed;
+    } else {
+	numAppendChars = 0;
+    }
+    for (dst=stringPtr->unicode + numOrigChars; numAppendChars-- > 0; dst++) {
+	bytes += TclUtfToUniChar(bytes, dst);
+    }
+    *dst = 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DupStringInternalRep --
+ *
+ *	Initialize the internal representation of a new Tcl_Obj to a copy of
+ *	the internal representation of an existing string object.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	copyPtr's internal rep is set to a copy of srcPtr's internal
+ *	representation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DupStringInternalRep(
+    Tcl_Obj *srcPtr,		/* Object with internal rep to copy. Must have
+				 * an internal rep of type "String". */
+    Tcl_Obj *copyPtr)		/* Object with internal rep to set. Must not
+				 * currently have an internal rep.*/
+{
+    String *srcStringPtr = GET_STRING(srcPtr);
+    String *copyStringPtr = NULL;
+
+#if COMPAT==0
+    if (srcStringPtr->numChars == -1) {
+	/*
+	 * The String struct in the source value holds zero useful data. Don't
+	 * bother copying it. Don't even bother allocating space in which to
+	 * copy it. Just let the copy be untyped.
+	 */
+
+	return;
+    }
+
+    if (srcStringPtr->hasUnicode) {
+	int copyMaxChars;
+
+	if (srcStringPtr->maxChars / 2 >= srcStringPtr->numChars) {
+	    copyMaxChars = 2 * srcStringPtr->numChars;
+	} else {
+	    copyMaxChars = srcStringPtr->maxChars;
+	}
+	copyStringPtr = stringAttemptAlloc(copyMaxChars);
+	if (copyStringPtr == NULL) {
+	    copyMaxChars = srcStringPtr->numChars;
+	    copyStringPtr = stringAlloc(copyMaxChars);
+	}
+	copyStringPtr->maxChars = copyMaxChars;
+	memcpy(copyStringPtr->unicode, srcStringPtr->unicode,
+		srcStringPtr->numChars * sizeof(Tcl_UniChar));
+	copyStringPtr->unicode[srcStringPtr->numChars] = 0;
+    } else {
+	copyStringPtr = stringAlloc(0);
+	copyStringPtr->maxChars = 0;
+	copyStringPtr->unicode[0] = 0;
+    }
+    copyStringPtr->hasUnicode = srcStringPtr->hasUnicode;
+    copyStringPtr->numChars = srcStringPtr->numChars;
+
+    /*
+     * Tricky point: the string value was copied by generic object management
+     * code, so it doesn't contain any extra bytes that might exist in the
+     * source object.
+     */
+
+    copyStringPtr->allocated = copyPtr->bytes ? copyPtr->length : 0;
+#else /* COMPAT!=0 */
+    /*
+     * If the src obj is a string of 1-byte Utf chars, then copy the string
+     * rep of the source object and create an "empty" Unicode internal rep for
+     * the new object. Otherwise, copy Unicode internal rep, and invalidate
+     * the string rep of the new object.
+     */
+
+    if (srcStringPtr->hasUnicode && srcStringPtr->numChars > 0) {
+	/*
+	 * Copy the full allocation for the Unicode buffer.
+	 */
+
+	copyStringPtr = stringAlloc(srcStringPtr->maxChars);
+	copyStringPtr->maxChars = srcStringPtr->maxChars;
+	memcpy(copyStringPtr->unicode, srcStringPtr->unicode,
+		srcStringPtr->numChars * sizeof(Tcl_UniChar));
+	copyStringPtr->unicode[srcStringPtr->numChars] = 0;
+	copyStringPtr->allocated = 0;
+    } else {
+	copyStringPtr = stringAlloc(0);
+	copyStringPtr->unicode[0] = 0;
+	copyStringPtr->maxChars = 0;
+
+	/*
+	 * Tricky point: the string value was copied by generic object
+	 * management code, so it doesn't contain any extra bytes that might
+	 * exist in the source object.
+	 */
+
+	copyStringPtr->allocated = copyPtr->length;
+    }
+    copyStringPtr->numChars = srcStringPtr->numChars;
+    copyStringPtr->hasUnicode = srcStringPtr->hasUnicode;
+#endif /* COMPAT==0 */
+
+    SET_STRING(copyPtr, copyStringPtr);
+    copyPtr->typePtr = &tclStringType;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SetStringFromAny --
+ *
+ *	Create an internal representation of type "String" for an object.
+ *
+ * Results:
+ *	This operation always succeeds and returns TCL_OK.
+ *
+ * Side effects:
+ *	Any old internal reputation for objPtr is freed and the internal
+ *	representation is set to "String".
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SetStringFromAny(
+    Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
+    Tcl_Obj *objPtr)		/* The object to convert. */
+{
+    if (objPtr->typePtr != &tclStringType) {
+	String *stringPtr = stringAlloc(0);
+
+	/*
+	 * Convert whatever we have into an untyped value. Just A String.
+	 */
+
+	(void) TclGetString(objPtr);
+	TclFreeIntRep(objPtr);
+
+	/*
+	 * Create a basic String intrep that just points to the UTF-8 string
+	 * already in place at objPtr->bytes.
+	 */
+
+	stringPtr->numChars = -1;
+	stringPtr->allocated = objPtr->length;
+	stringPtr->maxChars = 0;
+	stringPtr->hasUnicode = 0;
+	SET_STRING(objPtr, stringPtr);
+	objPtr->typePtr = &tclStringType;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * UpdateStringOfString --
+ *
+ *	Update the string representation for an object whose internal
+ *	representation is "String".
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The object's string may be set by converting its Unicode represention
+ *	to UTF format.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+UpdateStringOfString(
+    Tcl_Obj *objPtr)		/* Object with string rep to update. */
+{
+    String *stringPtr = GET_STRING(objPtr);
+
+    if (stringPtr->numChars == 0) {
+	TclInitStringRep(objPtr, tclEmptyStringRep, 0);
+    } else {
+	(void) ExtendStringRepWithUnicode(objPtr, stringPtr->unicode,
+		stringPtr->numChars);
+    }
+}
+
+static int
+ExtendStringRepWithUnicode(
+    Tcl_Obj *objPtr,
+    const Tcl_UniChar *unicode,
+    int numChars)
+{
+    /*
+     * Pre-condition: this is the "string" Tcl_ObjType.
+     */
+
+    int i, origLength, size = 0;
+    char *dst, buf[TCL_UTF_MAX];
+    String *stringPtr = GET_STRING(objPtr);
+
+    if (numChars < 0) {
+	numChars = UnicodeLength(unicode);
+    }
+
+    if (numChars == 0) {
+	return 0;
+    }
+
+    if (objPtr->bytes == NULL) {
+	objPtr->length = 0;
+    }
+    size = origLength = objPtr->length;
+
+    /*
+     * Quick cheap check in case we have more than enough room.
+     */
+
+    if (numChars <= (INT_MAX - size)/TCL_UTF_MAX
+	    && stringPtr->allocated >= size + numChars * TCL_UTF_MAX) {
+	goto copyBytes;
+    }
+
+    for (i = 0; i < numChars && size >= 0; i++) {
+	size += Tcl_UniCharToUtf((int) unicode[i], buf);
+    }
+    if (size < 0) {
+	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
+    }
+
+    /*
+     * Grow space if needed.
+     */
+
+    if (size > stringPtr->allocated) {
+	GrowStringBuffer(objPtr, size, 1);
+    }
+
+  copyBytes:
+    dst = objPtr->bytes + origLength;
+    for (i = 0; i < numChars; i++) {
+	dst += Tcl_UniCharToUtf((int) unicode[i], dst);
+    }
+    *dst = '\0';
+    objPtr->length = dst - objPtr->bytes;
+    return numChars;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FreeStringInternalRep --
+ *
+ *	Deallocate the storage associated with a String data object's internal
+ *	representation.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Frees memory.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FreeStringInternalRep(
+    Tcl_Obj *objPtr)		/* Object with internal rep to free. */
+{
+    ckfree(GET_STRING(objPtr));
+    objPtr->typePtr = NULL;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */