Updating libpng: Add libpng version 1.5.4

This is a clean copy of the official libpng 1.5.4 distribution, except
that various extraneous stuff (examples, tests, etc) have been
removed, as usual. The minor modifications to build it in Qt will
follow in a separate commit.

1 files changed, 1358 insertions, 0 deletions

diff --git a/src/3rdparty/libpng/pngpriv.h b/src/3rdparty/libpng/pngpriv.h
new file mode 100644
index 0000000..5b4d212
--- /dev/null
+++ b/src/3rdparty/libpng/pngpriv.h
@@ -0,0 +1,1358 @@
+
+/* pngpriv.h - private declarations for use inside libpng
+ *
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * Last changed in libpng 1.5.4 [July 7, 2011]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The symbols declared in this file (including the functions declared
+ * as PNG_EXTERN) are PRIVATE.  They are not part of the libpng public
+ * interface, and are not recommended for use by regular applications.
+ * Some of them may become public in the future; others may stay private,
+ * change in an incompatible way, or even disappear.
+ * Although the libpng users are not forbidden to include this header,
+ * they should be well aware of the issues that may arise from doing so.
+ */
+
+#ifndef PNGPRIV_H
+#define PNGPRIV_H
+
+/* Feature Test Macros.  The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+
+/* This is required for the definition of abort(), used as a last ditch
+ * error handler when all else fails.
+ */
+#include <stdlib.h>
+
+#define PNGLIB_BUILD
+#ifdef PNG_USER_CONFIG
+#  include "pngusr.h"
+   /* These should have been defined in pngusr.h */
+#  ifndef PNG_USER_PRIVATEBUILD
+#    define PNG_USER_PRIVATEBUILD "Custom libpng build"
+#  endif
+#  ifndef PNG_USER_DLLFNAME_POSTFIX
+#    define PNG_USER_DLLFNAME_POSTFIX "Cb"
+#  endif
+#endif
+#include "png.h"
+#include "pnginfo.h"
+#include "pngstruct.h"
+
+/* This is used for 16 bit gamma tables - only the top level pointers are const,
+ * this could be changed:
+ */
+typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
+
+/* Added at libpng-1.2.9 */
+/* Moved to pngpriv.h at libpng-1.5.0 */
+
+/* config.h is created by and PNG_CONFIGURE_LIBPNG is set by the "configure"
+ * script.  We may need it here to get the correct configuration on things
+ * like limits.
+ */
+#ifdef PNG_CONFIGURE_LIBPNG
+#  ifdef HAVE_CONFIG_H
+#    include "config.h"
+#  endif
+#endif
+
+/* Moved to pngpriv.h at libpng-1.5.0 */
+/* NOTE: some of these may have been used in external applications as
+ * these definitions were exposed in pngconf.h prior to 1.5.
+ */
+
+/* If you are running on a machine where you cannot allocate more
+ * than 64K of memory at once, uncomment this.  While libpng will not
+ * normally need that much memory in a chunk (unless you load up a very
+ * large file), zlib needs to know how big of a chunk it can use, and
+ * libpng thus makes sure to check any memory allocation to verify it
+ * will fit into memory.
+ *
+ * zlib provides 'MAXSEG_64K' which, if defined, indicates the
+ * same limit and pngconf.h (already included) sets the limit
+ * if certain operating systems are detected.
+ */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+#  define PNG_MAX_MALLOC_64K
+#endif
+
+#ifndef PNG_UNUSED
+/* Unused formal parameter warnings are silenced using the following macro
+ * which is expected to have no bad effects on performance (optimizing
+ * compilers will probably remove it entirely).  Note that if you replace
+ * it with something other than whitespace, you must include the terminating
+ * semicolon.
+ */
+#  define PNG_UNUSED(param) (void)param;
+#endif
+
+/* Just a little check that someone hasn't tried to define something
+ * contradictory.
+ */
+#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
+#  undef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 65536L
+#endif
+
+/* PNG_STATIC is used to mark internal file scope functions if they need to be
+ * accessed for implementation tests (see the code in tests/?*).
+ */
+#ifndef PNG_STATIC
+#   define PNG_STATIC static
+#endif
+
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.4 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+#  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+#  define png_warning(s1,s2) ((void)(s1))
+#  define png_chunk_warning(s1,s2) ((void)(s1))
+#  define png_warning_parameter(p,number,string) ((void)0)
+#  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+#  define png_warning_parameter_signed(p,number,format,value) ((void)0)
+#  define png_formatted_warning(pp,p,message) ((void)(pp))
+#  define PNG_WARNING_PARAMETERS(p)
+#endif
+#ifndef PNG_ERROR_TEXT_SUPPORTED
+#  define png_error(s1,s2) png_err(s1)
+#  define png_chunk_error(s1,s2) png_err(s1)
+#  define png_fixed_error(s1,s2) png_err(s1)
+#endif
+
+#ifndef PNG_EXTERN
+/* The functions exported by PNG_EXTERN are internal functions, which
+ * aren't usually used outside the library (as far as I know), so it is
+ * debatable if they should be exported at all.  In the future, when it
+ * is possible to have run-time registry of chunk-handling functions,
+ * some of these might be made available again.
+#  define PNG_EXTERN extern
+ */
+#  define PNG_EXTERN
+#endif
+
+/* Some fixed point APIs are still required even if not exported because
+ * they get used by the corresponding floating point APIs.  This magic
+ * deals with this:
+ */
+#ifdef PNG_FIXED_POINT_SUPPORTED
+#  define PNGFAPI PNGAPI
+#else
+#  define PNGFAPI /* PRIVATE */
+#endif
+
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   /* png.c requires the following ANSI-C constants if the conversion of
+    * floating point to ASCII is implemented therein:
+    *
+    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
+    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
+    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
+    */
+#  include <float.h>
+
+#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+     /* We need to check that <math.h> hasn't already been included earlier
+      * as it seems it doesn't agree with <fp.h>, yet we should really use
+      * <fp.h> if possible.
+      */
+#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+#      include <fp.h>
+#    endif
+#  else
+#    include <math.h>
+#  endif
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+     /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+      * MATH=68881
+      */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+    defined(_WIN32) || defined(__WIN32__)
+#  include <windows.h>  /* defines _WINDOWS_ macro */
+#endif
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private.  Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Memory model/platform independent fns */
+#ifndef PNG_ABORT
+#  ifdef _WINDOWS_
+#    define PNG_ABORT() ExitProcess(0)
+#  else
+#    define PNG_ABORT() abort()
+#  endif
+#endif
+
+#ifdef USE_FAR_KEYWORD
+/* Use this to make far-to-near assignments */
+#  define CHECK   1
+#  define NOCHECK 0
+#  define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
+#  define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
+#  define png_strlen  _fstrlen
+#  define png_memcmp  _fmemcmp    /* SJT: added */
+#  define png_memcpy  _fmemcpy
+#  define png_memset  _fmemset
+#else
+#  ifdef _WINDOWS_  /* Favor Windows over C runtime fns */
+#    define CVT_PTR(ptr)         (ptr)
+#    define CVT_PTR_NOCHECK(ptr) (ptr)
+#    define png_strlen  lstrlenA
+#    define png_memcmp  memcmp
+#    define png_memcpy  CopyMemory
+#    define png_memset  memset
+#  else
+#    define CVT_PTR(ptr)         (ptr)
+#    define CVT_PTR_NOCHECK(ptr) (ptr)
+#    define png_strlen  strlen
+#    define png_memcmp  memcmp      /* SJT: added */
+#    define png_memcpy  memcpy
+#    define png_memset  memset
+#  endif
+#endif
+/* End of memory model/platform independent support */
+/* End of 1.5.0beta36 move from pngconf.h */
+
+/* CONSTANTS and UTILITY MACROS
+ * These are used internally by libpng and not exposed in the API
+ */
+
+/* Various modes of operation.  Note that after an init, mode is set to
+ * zero automatically when the structure is created.  Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
+ */
+/* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
+/* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
+#define PNG_HAVE_IDAT               0x04
+/* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
+#define PNG_HAVE_IEND               0x10
+#define PNG_HAVE_gAMA               0x20
+#define PNG_HAVE_cHRM               0x40
+#define PNG_HAVE_sRGB               0x80
+#define PNG_HAVE_CHUNK_HEADER      0x100
+#define PNG_WROTE_tIME             0x200
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
+#define PNG_BACKGROUND_IS_GRAY     0x800
+#define PNG_HAVE_PNG_SIGNATURE    0x1000
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+
+/* Flags for the transformations the PNG library does on the image data */
+#define PNG_BGR                 0x0001
+#define PNG_INTERLACE           0x0002
+#define PNG_PACK                0x0004
+#define PNG_SHIFT               0x0008
+#define PNG_SWAP_BYTES          0x0010
+#define PNG_INVERT_MONO         0x0020
+#define PNG_QUANTIZE            0x0040
+#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100
+#define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
+#define PNG_RGBA                0x0800
+#define PNG_EXPAND              0x1000
+#define PNG_GAMMA               0x2000
+#define PNG_GRAY_TO_RGB         0x4000
+#define PNG_FILLER              0x8000L
+#define PNG_PACKSWAP           0x10000L
+#define PNG_SWAP_ALPHA         0x20000L
+#define PNG_STRIP_ALPHA        0x40000L
+#define PNG_INVERT_ALPHA       0x80000L
+#define PNG_USER_TRANSFORM    0x100000L
+#define PNG_RGB_TO_GRAY_ERR   0x200000L
+#define PNG_RGB_TO_GRAY_WARN  0x400000L
+#define PNG_RGB_TO_GRAY       0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA      0x800000L  /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA         0x1000000L  /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS       0x2000000L  /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8     0x4000000L  /* Added to libpng-1.5.4 */
+                       /*   0x8000000L  unused */
+                       /*  0x10000000L  unused */
+                       /*  0x20000000L  unused */
+                       /*  0x40000000L  unused */
+
+/* Flags for png_create_struct */
+#define PNG_STRUCT_PNG   0x0001
+#define PNG_STRUCT_INFO  0x0002
+
+/* Scaling factor for filter heuristic weighting calculations */
+#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
+#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
+
+/* Flags for the png_ptr->flags rather than declaring a byte for each one */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
+#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
+#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
+#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
+#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
+#define PNG_FLAG_ZLIB_FINISHED            0x0020
+#define PNG_FLAG_ROW_INIT                 0x0040
+#define PNG_FLAG_FILLER_AFTER             0x0080
+#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
+#define PNG_FLAG_CRC_CRITICAL_USE         0x0400
+#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
+#define PNG_FLAG_ASSUME_sRGB              0x1000  /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000  /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000  /* Added to libpng-1.5.4 */
+#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
+#define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
+#define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
+#define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L
+#define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L
+#define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000L
+                                  /*      0x200000L  unused */
+                                  /*      0x400000L  unused */
+#define PNG_FLAG_BENIGN_ERRORS_WARN       0x800000L  /* Added to libpng-1.4.0 */
+#define PNG_FLAG_ZTXT_CUSTOM_STRATEGY    0x1000000L  /* 5 lines added */
+#define PNG_FLAG_ZTXT_CUSTOM_LEVEL       0x2000000L  /* to libpng-1.5.4 */
+#define PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL   0x4000000L
+#define PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS 0x8000000L
+#define PNG_FLAG_ZTXT_CUSTOM_METHOD      0x10000000L
+                                  /*     0x20000000L  unused */
+                                  /*     0x40000000L  unused */
+
+#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
+                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
+
+#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
+                                     PNG_FLAG_CRC_CRITICAL_IGNORE)
+
+#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
+                                     PNG_FLAG_CRC_CRITICAL_MASK)
+
+/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
+ * can handle at once.  This type need be no larger than 16 bits (so maximum of
+ * 65535), this define allows us to discover how big it is, but limited by the
+ * maximuum for png_size_t.  The value can be overriden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
+ */
+#ifndef ZLIB_IO_MAX
+#  define ZLIB_IO_MAX ((uInt)-1)
+#endif
+
+/* Save typing and make code easier to understand */
+
+#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
+   abs((int)((c1).green) - (int)((c2).green)) + \
+   abs((int)((c1).blue) - (int)((c2).blue)))
+
+/* Added to libpng-1.2.6 JB */
+#define PNG_ROWBYTES(pixel_bits, width) \
+    ((pixel_bits) >= 8 ? \
+    ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
+    (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
+
+/* PNG_OUT_OF_RANGE returns true if value is outside the range
+ * ideal-delta..ideal+delta.  Each argument is evaluated twice.
+ * "ideal" and "delta" should be constants, normally simple
+ * integers, "value" a variable. Added to libpng-1.2.6 JB
+ */
+#define PNG_OUT_OF_RANGE(value, ideal, delta) \
+   ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
+
+/* Conversions between fixed and floating point, only defined if
+ * required (to make sure the code doesn't accidentally use float
+ * when it is supposedly disabled.)
+ */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* The floating point conversion can't overflow, though it can and
+ * does lose accuracy relative to the original fixed point value.
+ * In practice this doesn't matter because png_fixed_point only
+ * stores numbers with very low precision.  The png_ptr and s
+ * arguments are unused by default but are there in case error
+ * checking becomes a requirement.
+ */
+#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
+
+/* The fixed point conversion performs range checking and evaluates
+ * its argument multiple times, so must be used with care.  The
+ * range checking uses the PNG specification values for a signed
+ * 32 bit fixed point value except that the values are deliberately
+ * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
+ * (2^31-1) * 100000). 's' is a string that describes the value being
+ * converted.
+ *
+ * NOTE: this macro will raise a png_error if the range check fails,
+ * therefore it is normally only appropriate to use this on values
+ * that come from API calls or other sources where an out of range
+ * error indicates a programming error, not a data error!
+ *
+ * NOTE: by default this is off - the macro is not used - because the
+ * function call saves a lot of code.
+ */
+#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
+#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
+    ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
+#else
+PNG_EXTERN png_fixed_point png_fixed PNGARG((png_structp png_ptr, double fp,
+   png_const_charp text));
+#endif
+#endif
+
+/* Constant strings for known chunk types.  If you need to add a chunk,
+ * define the name here, and add an invocation of the macro wherever it's
+ * needed.
+ */
+#define PNG_IHDR PNG_CONST png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
+#define PNG_IDAT PNG_CONST png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
+#define PNG_IEND PNG_CONST png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
+#define PNG_PLTE PNG_CONST png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
+#define PNG_bKGD PNG_CONST png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
+#define PNG_cHRM PNG_CONST png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
+#define PNG_gAMA PNG_CONST png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
+#define PNG_hIST PNG_CONST png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
+#define PNG_iCCP PNG_CONST png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
+#define PNG_iTXt PNG_CONST png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
+#define PNG_oFFs PNG_CONST png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
+#define PNG_pCAL PNG_CONST png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
+#define PNG_sCAL PNG_CONST png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
+#define PNG_pHYs PNG_CONST png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
+#define PNG_sBIT PNG_CONST png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
+#define PNG_sPLT PNG_CONST png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
+#define PNG_sRGB PNG_CONST png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
+#define PNG_sTER PNG_CONST png_byte png_sTER[5] = {115,  84,  69,  82, '\0'}
+#define PNG_tEXt PNG_CONST png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
+#define PNG_tIME PNG_CONST png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
+#define PNG_tRNS PNG_CONST png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
+#define PNG_zTXt PNG_CONST png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
+
+/* Gamma values (new at libpng-1.5.4): */
+#define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
+
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* These functions are used internally in the code.  They generally
+ * shouldn't be used unless you are writing code to add or replace some
+ * functionality in libpng.  More information about most functions can
+ * be found in the files where the functions are located.
+ */
+
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_EXTERN int png_user_version_check(png_structp png_ptr,
+   png_const_charp user_png_ver);
+
+/* Allocate memory for an internal libpng struct */
+PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
+   PNG_ALLOCATED);
+
+/* Free memory from internal libpng struct */
+PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));
+
+PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct_2,
+   PNGARG((int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)),
+   PNG_ALLOCATED);
+PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
+    png_free_ptr free_fn, png_voidp mem_ptr));
+
+/* Free any memory that info_ptr points to and reset struct. */
+PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+
+/* Function to allocate memory for zlib.  PNGAPI is disallowed. */
+PNG_EXTERN PNG_FUNCTION(voidpf,png_zalloc,PNGARG((voidpf png_ptr, uInt items,
+   uInt size)),PNG_ALLOCATED);
+
+/* Function to free memory for zlib.  PNGAPI is disallowed. */
+PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));
+
+/* Next four functions are used internally as callbacks.  PNGCBAPI is required
+ * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
+ * PNGCBAPI at 1.5.0
+ */
+
+PNG_EXTERN void PNGCBAPI png_default_read_data PNGARG((png_structp png_ptr,
+    png_bytep data, png_size_t length));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_EXTERN void PNGCBAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
+    png_bytep buffer, png_size_t length));
+#endif
+
+PNG_EXTERN void PNGCBAPI png_default_write_data PNGARG((png_structp png_ptr,
+    png_bytep data, png_size_t length));
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_STDIO_SUPPORTED
+PNG_EXTERN void PNGCBAPI png_default_flush PNGARG((png_structp png_ptr));
+#  endif
+#endif
+
+/* Reset the CRC variable */
+PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
+
+/* Write the "data" buffer to whatever output you are using */
+PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr,
+    png_const_bytep data, png_size_t length));
+
+/* Read and check the PNG file signature */
+PNG_EXTERN void png_read_sig PNGARG((png_structp png_ptr, png_infop info_ptr));
+
+/* Read the chunk header (length + type name) */
+PNG_EXTERN png_uint_32 png_read_chunk_header PNGARG((png_structp png_ptr));
+
+/* Read data from whatever input you are using into the "data" buffer */
+PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
+    png_size_t length));
+
+/* Read bytes into buf, and update png_ptr->crc */
+PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
+    png_size_t length));
+
+/* Decompress data in a chunk that uses compression */
+#if defined(PNG_READ_COMPRESSED_TEXT_SUPPORTED)
+PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
+    int comp_type, png_size_t chunklength, png_size_t prefix_length,
+    png_size_t *data_length));
+#endif
+
+/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
+PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));
+
+/* Read the CRC from the file and compare it to the libpng calculated CRC */
+PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));
+
+/* Calculate the CRC over a section of data.  Note that we are only
+ * passing a maximum of 64K on systems that have this as a memory limit,
+ * since this is the maximum buffer size we can specify.
+ */
+PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr,
+    png_const_bytep ptr, png_size_t length));
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
+#endif
+
+/* Write various chunks */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.
+ */
+PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
+    png_uint_32 height,
+    int bit_depth, int color_type, int compression_method, int filter_method,
+    int interlace_method));
+
+PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr,
+    png_const_colorp palette, png_uint_32 num_pal));
+
+PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
+    png_size_t length));
+
+PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
+#  endif
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
+    png_fixed_point file_gamma));
+#  endif
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr,
+    png_const_color_8p sbit, int color_type));
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
+    double white_x, double white_y,
+    double red_x, double red_y, double green_x, double green_y,
+    double blue_x, double blue_y));
+#  endif
+PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
+    png_fixed_point int_white_x, png_fixed_point int_white_y,
+    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
+    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
+    png_fixed_point int_blue_y));
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
+    int intent));
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
+    png_const_charp name, int compression_type,
+    png_const_charp profile, int proflen));
+   /* Note to maintainer: profile should be png_bytep */
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
+    png_const_sPLT_tp palette));
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr,
+    png_const_bytep trans, png_const_color_16p values, int number,
+    int color_type));
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
+    png_const_color_16p values, int color_type));
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr,
+    png_const_uint_16p hist, int num_hist));
+#endif
+
+/* Chunks that have keywords */
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
+    png_const_charp key, png_charpp new_key));
+#endif
+
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_const_charp key,
+    png_const_charp text, png_size_t text_len));
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_const_charp key,
+    png_const_charp text, png_size_t text_len, int compression));
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
+    int compression, png_const_charp key, png_const_charp lang,
+    png_const_charp lang_key, png_const_charp text));
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
+PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_const_textp text_ptr, int num_text));
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
+    png_int_32 x_offset, png_int_32 y_offset, int unit_type));
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
+    png_int_32 X0, png_int_32 X1, int type, int nparams,
+    png_const_charp units, png_charpp params));
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
+    png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
+    int unit_type));
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
+    png_const_timep mod_time));
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
+    int unit, png_const_charp width, png_const_charp height));
+#endif
+
+/* Called when finished processing a row of data */
+PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
+
+/* Internal use only.   Called before first row of data */
+PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
+
+/* Combine a row of data, dealing with alpha, etc. if requested */
+PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
+    int mask));
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Expand an interlaced row */
+/* OLD pre-1.0.9 interface:
+PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
+    png_bytep row, int pass, png_uint_32 transformations));
+ */
+PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr));
+#endif
+
+/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Grab pixels out of a row for an interlaced pass */
+PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
+    png_bytep row, int pass));
+#endif
+
+/* Unfilter a row */
+PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
+    png_row_infop row_info, png_bytep row, png_const_bytep prev_row,
+    int filter));
+
+/* Choose the best filter to use and filter the row data */
+PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
+    png_row_infop row_info));
+
+/* Finish a row while reading, dealing with interlacing passes, etc. */
+PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
+
+/* Initialize the row buffers, etc. */
+PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Optional call to update the users info structure */
+PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+#endif
+
+/* These are the functions that do the transformations */
+#ifdef PNG_READ_FILLER_SUPPORTED
+PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
+    png_bytep row, png_uint_32 filler, png_uint_32 flags));
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_strip_channel PNGARG((png_row_infop row_info,
+    png_bytep row, int at_start));
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr,
+    png_row_infop row_info, png_bytep row));
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info,
+    png_bytep row, png_const_color_8p sig_bits));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+PNG_EXTERN void png_do_scale_16_to_8 PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+PNG_EXTERN void png_do_quantize PNGARG((png_row_infop row_info,
+    png_bytep row, png_const_bytep palette_lookup,
+    png_const_bytep quantize_lookup));
+
+#  ifdef PNG_CORRECT_PALETTE_SUPPORTED
+PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
+    png_colorp palette, int num_palette));
+#  endif
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
+   png_bytep row, png_uint_32 bit_depth));
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info,
+    png_bytep row, png_const_color_8p bit_depth));
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+PNG_EXTERN void png_do_compose PNGARG((png_row_infop row_info,
+    png_bytep row, png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info,
+    png_bytep row, png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+PNG_EXTERN void png_do_encode_alpha PNGARG((png_row_infop row_info,
+   png_bytep row, png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
+    png_bytep row, png_const_colorp palette, png_const_bytep trans,
+    int num_trans));
+PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
+    png_bytep row, png_const_color_16p trans_color));
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+PNG_EXTERN void png_do_expand_16 PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+/* The following decodes the appropriate chunks, and does error correction,
+ * then calls the appropriate callback for the chunk if it is valid.
+ */
+
+/* Decode the IHDR chunk */
+PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_EXTERN void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif /* PNG_READ_iCCP_SUPPORTED */
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+PNG_EXTERN void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif /* PNG_READ_sPLT_SUPPORTED */
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+    png_uint_32 length));
+#endif
+
+PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_uint_32 length));
+
+PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
+    png_const_bytep chunk_name));
+
+/* Handle the transformations for reading and writing */
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
+    png_uint_32 length));
+PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
+    png_bytep buffer, png_size_t buffer_length));
+PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
+    png_bytep buffer, png_size_t buffer_length));
+PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));
+PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));
+#  ifdef PNG_READ_tEXt_SUPPORTED
+PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+#  endif
+#  ifdef PNG_READ_zTXt_SUPPORTED
+PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+#  endif
+#  ifdef PNG_READ_iTXt_SUPPORTED
+PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
+    png_infop info_ptr));
+#  endif
+
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
+    png_bytep row));
+PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
+    png_bytep row));
+#endif
+
+/* Added at libpng version 1.4.0 */
+#ifdef PNG_CHECK_cHRM_SUPPORTED
+PNG_EXTERN int png_check_cHRM_fixed PNGARG((png_structp png_ptr,
+    png_fixed_point int_white_x, png_fixed_point int_white_y,
+    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
+    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
+    png_fixed_point int_blue_y));
+#endif
+
+#ifdef PNG_CHECK_cHRM_SUPPORTED
+/* Added at libpng version 1.2.34 and 1.4.0 */
+/* Currently only used by png_check_cHRM_fixed */
+PNG_EXTERN void png_64bit_product PNGARG((long v1, long v2,
+    unsigned long *hi_product, unsigned long *lo_product));
+#endif
+
+/* Added at libpng version 1.4.0 */
+PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type));
+
+/* Free all memory used by the read (old method - NOT DLL EXPORTED) */
+PNG_EXTERN void png_read_destroy PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_infop end_info_ptr));
+
+/* Free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
+PNG_EXTERN void png_write_destroy PNGARG((png_structp png_ptr));
+
+#ifdef USE_FAR_KEYWORD  /* memory model conversion function */
+PNG_EXTERN void *png_far_to_near PNGARG((png_structp png_ptr, png_voidp ptr,
+    int check));
+#endif /* USE_FAR_KEYWORD */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_EXTERN PNG_FUNCTION(void, png_fixed_error, (png_structp png_ptr,
+   png_const_charp name),PNG_NORETURN);
+#endif
+
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end.  Always leaves the buffer nul terminated.  Never errors out (and
+ * there is no error code.)
+ */
+PNG_EXTERN size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+    png_const_charp string);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.  This utility only
+ * does unsigned values.
+ */
+PNG_EXTERN png_charp png_format_number(png_const_charp start, png_charp end,
+   int format, png_alloc_size_t number);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+   png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u   2
+#define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d   2
+#define PNG_NUMBER_FORMAT_x     3
+#define PNG_NUMBER_FORMAT_02x   4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.4 */
+#  define PNG_WARNING_PARAMETER_SIZE 32
+#  define PNG_WARNING_PARAMETER_COUNT 8
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+   PNG_WARNING_PARAMETER_SIZE];
+
+PNG_EXTERN void png_warning_parameter(png_warning_parameters p, int number,
+    png_const_charp string);
+    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+     * including the trailing '\0'.
+     */
+PNG_EXTERN void png_warning_parameter_unsigned(png_warning_parameters p,
+    int number, int format, png_alloc_size_t value);
+    /* Use png_alloc_size_t because it is an unsigned type as big as any we
+     * need to output.  Use the following for a signed value.
+     */
+PNG_EXTERN void png_warning_parameter_signed(png_warning_parameters p,
+    int number, int format, png_int_32 value);
+
+PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
+    png_warning_parameters p, png_const_charp message);
+    /* 'message' follows the X/Open approach of using @1, @2 to insert
+     * parameters previously supplied using the above functions.  Errors in
+     * specifying the paramters will simple result in garbage substitutions.
+     */
+#endif
+
+/* ASCII to FP interfaces, currently only implemented if sCAL
+ * support is required.
+ */
+#if defined(PNG_READ_sCAL_SUPPORTED)
+/* MAX_DIGITS is actually the maximum number of characters in an sCAL
+ * width or height, derived from the precision (number of significant
+ * digits - a build time settable option) and assumpitions about the
+ * maximum ridiculous exponent.
+ */
+#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_EXTERN void png_ascii_from_fp PNGARG((png_structp png_ptr, png_charp ascii,
+    png_size_t size, double fp, unsigned int precision));
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_EXTERN void png_ascii_from_fixed PNGARG((png_structp png_ptr,
+    png_charp ascii, png_size_t size, png_fixed_point fp));
+#endif /* FIXED_POINT */
+#endif /* READ_sCAL */
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* An internal API to validate the format of a floating point number.
+ * The result is the index of the next character.  If the number is
+ * not valid it will be the index of a character in the supposed number.
+ *
+ * The format of a number is defined in the PNG extensions specification
+ * and this API is strictly conformant to that spec, not anyone elses!
+ *
+ * The format as a regular expression is:
+ *
+ * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
+ *
+ * or:
+ *
+ * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
+ *
+ * The complexity is that either integer or fraction must be present and the
+ * fraction is permitted to have no digits only if the integer is present.
+ *
+ * NOTE: The dangling E problem.
+ *   There is a PNG valid floating point number in the following:
+ *
+ *       PNG floating point numb1.ers are not greedy.
+ *
+ *   Working this out requires *TWO* character lookahead (because of the
+ *   sign), the parser does not do this - it will fail at the 'r' - this
+ *   doesn't matter for PNG sCAL chunk values, but it requires more care
+ *   if the value were ever to be embedded in something more complex.  Use
+ *   ANSI-C strtod if you need the lookahead.
+ */
+/* State table for the parser. */
+#define PNG_FP_INTEGER    0  /* before or in integer */
+#define PNG_FP_FRACTION   1  /* before or in fraction */
+#define PNG_FP_EXPONENT   2  /* before or in exponent */
+#define PNG_FP_STATE      3  /* mask for the above */
+#define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
+#define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
+#define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
+#define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
+#define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
+
+/* These three values don't affect the parser.  They are set but not used.
+ */
+#define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
+#define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
+#define PNG_FP_NONZERO  256  /* A non-zero value */
+#define PNG_FP_STICKY   448  /* The above three flags */
+
+/* This is available for the caller to store in 'state' if required.  Do not
+ * call the parser after setting it (the parser sometimes clears it.)
+ */
+#define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
+
+/* Result codes for the parser (boolean - true meants ok, false means
+ * not ok yet.)
+ */
+#define PNG_FP_MAYBE      0  /* The number may be valid in the future */
+#define PNG_FP_OK         1  /* The number is valid */
+
+/* Tests on the sticky non-zero and negative flags.  To pass these checks
+ * the state must also indicate that the whole number is valid - this is
+ * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
+ * is equivalent to PNG_FP_OK above.)
+ */
+#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
+   /* NZ_MASK: the string is valid and a non-zero negative value */
+#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
+   /* Z MASK: the string is valid and a non-zero value. */
+   /* PNG_FP_SAW_DIGIT: the string is valid. */
+#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
+#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
+#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
+ 
+/* The actual parser.  This can be called repeatedly, it updates
+ * the index into the string and the state variable (which must
+ * be initialzed to 0).  It returns a result code, as above.  There
+ * is no point calling the parser any more if it fails to advance to
+ * the end of the string - it is stuck on an invalid character (or
+ * terminated by '\0').
+ *
+ * Note that the pointer will consume an E or even an E+ then leave
+ * a 'maybe' state even though a preceding integer.fraction is valid.
+ * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
+ * a valid number.  It's possible to recover from this by calling
+ * the parser again (from the start, with state 0) but with a string
+ * that omits the last character (i.e. set the size to the index of
+ * the problem character.)  This has not been tested within libpng.
+ */
+PNG_EXTERN int png_check_fp_number PNGARG((png_const_charp string,
+    png_size_t size, int *statep, png_size_tp whereami));
+
+/* This is the same but it checks a complete string and returns true
+ * only if it just contains a floating point number.  As of 1.5.4 this
+ * function also returns the state at the end of parsing the number if
+ * it was valid (otherwise it returns 0.)  This can be used for testing
+ * for negative or zero values using the sticky flag.
+ */
+PNG_EXTERN int png_check_fp_string PNGARG((png_const_charp string,
+    png_size_t size));
+#endif /* pCAL || sCAL */
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* Added at libpng version 1.5.0 */
+/* This is a utility to provide a*times/div (rounded) and indicate
+ * if there is an overflow.  The result is a boolean - false (0)
+ * for overflow, true (1) if no overflow, in which case *res
+ * holds the result.
+ */
+PNG_EXTERN int png_muldiv PNGARG((png_fixed_point_p res, png_fixed_point a,
+    png_int_32 multiplied_by, png_int_32 divided_by));
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* Same deal, but issue a warning on overflow and return 0. */
+PNG_EXTERN png_fixed_point png_muldiv_warn PNGARG((png_structp png_ptr,
+    png_fixed_point a, png_int_32 multiplied_by, png_int_32 divided_by));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Calculate a reciprocal - used for gamma values.  This returns
+ * 0 if the argument is 0 in order to maintain an undefined value,
+ * there are no warnings.
+ */
+PNG_EXTERN png_fixed_point png_reciprocal PNGARG((png_fixed_point a));
+
+/* The same but gives a reciprocal of the product of two fixed point
+ * values.  Accuracy is suitable for gamma calculations but this is
+ * not exact - use png_muldiv for that.
+ */
+PNG_EXTERN png_fixed_point png_reciprocal2 PNGARG((png_fixed_point a,
+    png_fixed_point b));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Internal fixed point gamma correction.  These APIs are called as
+ * required to convert single values - they don't need to be fast,
+ * they are not used when processing image pixel values.
+ *
+ * While the input is an 'unsigned' value it must actually be the
+ * correct bit value - 0..255 or 0..65535 as required.
+ */
+PNG_EXTERN png_uint_16 png_gamma_correct PNGARG((png_structp png_ptr,
+    unsigned int value, png_fixed_point gamma_value));
+PNG_EXTERN int png_gamma_significant PNGARG((png_fixed_point gamma_value));
+PNG_EXTERN png_uint_16 png_gamma_16bit_correct PNGARG((unsigned int value,
+    png_fixed_point gamma_value));
+PNG_EXTERN png_byte png_gamma_8bit_correct PNGARG((unsigned int value,
+    png_fixed_point gamma_value));
+PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr,
+    int bit_depth));
+#endif
+
+/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
+
+
+#include "pngdebug.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNGPRIV_H */