dslinux/lib/libpng ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE Makefile README TODO Y2KINFO configure example.c libpng.3 libpng.txt libpngpf.3 png.5 png.c png.h pngasmrd.h pngbar.jpg pngbar.png pngconf.h pngerror.c pnggccrd.c pngget.c pngmem.c pngnow.png pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtest.c pngtest.png pngtrans.c pngvcrd.c pngwio.c pngwrite.c pngwtran.c pngwutil.c

pepsiman dslinux_pepsiman at user.in-berlin.de
Sat Nov 25 11:05:14 CET 2006


Update of /cvsroot/dslinux/dslinux/lib/libpng
In directory antilope:/tmp/cvs-serv15394

Added Files:
	ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE Makefile README TODO 
	Y2KINFO configure example.c libpng.3 libpng.txt libpngpf.3 
	png.5 png.c png.h pngasmrd.h pngbar.jpg pngbar.png pngconf.h 
	pngerror.c pnggccrd.c pngget.c pngmem.c pngnow.png pngpread.c 
	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtest.c 
	pngtest.png pngtrans.c pngvcrd.c pngwio.c pngwrite.c 
	pngwtran.c pngwutil.c 
Log Message:
Merge libpng from uclinux_branch

--- NEW FILE: INSTALL ---

Installing libpng version 1.0.12 - June 8, 2001

Before installing libpng, you must first install zlib.  zlib
can usually be found wherever you got libpng.  zlib can be
placed in another directory, at the same level as libpng.
Note that your system might already have a preinstalled
zlib, but you will still need to have access to the
zlib.h and zconf.h include files that correspond to the
version of zlib that's installed.

You can rename the directories that you downloaded (they
might be called "libpng-1.0.12" or "lpng109" and "zlib-1.1.3"
or "zlib113") so that you have directories called "zlib" and "libpng".

Your directory structure should look like this:

   ..       (the parent directory)
      libpng  (this directory)
          INSTALL (this file)
          README
          *.h
          *.c
          contrib
             gregbook
             msvctest
             pngminus
             pngsuite
             visupng
          projects
             beos
             borland
             msvc
             netware.txt
             wince.txt
          scripts
             makefile.*
          pngtest.png
          etc.
      zlib
          README
          *.h
          *.c
          contrib
          etc.

If the line endings in the files look funny, you may wish to get the other
distribution of libpng.  It is available in both tar.gz (UNIX style line
endings) and zip (DOS style line endings) formats.

If you are building libpng with MSVC, you can enter the libpng\msvc directory
and follow the instructions in msvc\README.txt.

You can build libpng for WindowsCE by entering the downloading and installing
the libpng\wince directory as instructed in the projects\wince.txt file, and
then following the instructions in the README* files.  Similarly, you can
build libpng for Netware as instructed in projects\netware.txt.

Else enter the zlib directory and follow the instructions in zlib/README,
then come back here and choose the appropriate makefile.sys in the scripts
directory.

The files that are presently available in the scripts directory
include

 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.linux    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.12)
 makefile.gcmmx    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.12,
                       uses assembler code tuned for Intel MMX platform)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
                       ftp://ftp.cs.wisc.edu/ghost)
 makefile.aix      =>  AIX makefile
 makefile.cygwin   =>  Cygwin/gcc makefile
 makefile.dec      =>  DEC Alpha UNIX makefile
 makefile.hpgcc    =>  HPUX makefile using gcc
 makefile.hpux     =>  HPUX (10.20 and 11.00) makefile
 makefile.ibmc     =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
 makefile.intel    =>  Intel C/C++ version 4.0 and later
 libpng.icc        =>  Project file for IBM VisualAge/C++ version 4.0 or later
 makefile.macosx   =>  MACOS X Makefile
 makefile.netbsd   =>  NetBSD/cc makefile, uses PNGGCCRD
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.sggcc    =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.12)
 makefile.sunos    =>  Sun makefile
 makefile.solaris  =>  Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.12)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.mips     =>  MIPS makefile
 makefile.acorn    =>  Acorn makefile
 makefile.amiga    =>  Amiga makefile
 smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
                       (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
 makefile.atari    =>  Atari makefile
 makefile.beos     =>  BEOS makefile for X86
 makefile.bor      =>  Borland makefile (uses bcc)
 makefile.bc32     =>  32-bit Borland C++ (all modules compiled in C mode)
 makefile.bd32     =>  To make a png32bd.dll with Borland C++ 4.5
 makefile.tc3      =>  Turbo C 3.0 makefile
 makefile.dj2      =>  DJGPP 2 makefile
 makefile.msc      =>  Microsoft C makefile
 makefile.vcawin32 =>  makefile for Microsoft Visual C++ 5.0 and later (uses
                       assembler code tuned for Intel MMX platform)
 makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later (does
                       not use assembler code)
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires pngos2.def)
 pngos2.def        =>  OS/2 module definition file used by makefile.os2
 makefile.watcom   =>  Watcom 10a+ Makefile, 32-bit flat memory model
 makevms.com       =>  VMS build script
 descrip.mms       =>  VMS makefile for MMS or MMK
 pngdef.pas        =>  Defines for a png32bd.dll with Borland C++ 4.5
 SCOPTIONS.ppc     =>  Used with smakefile.ppc

Copy the file (or files) that you need from the
scripts directory into this directory, for example

   MSDOS example: copy scripts\makefile.msc makefile
   UNIX example:    cp scripts/makefile.std makefile

Read the makefile to see if you need to change any source or
target directories to match your preferences.

Then read pngconf.h to see if you want to make any configuration
changes.

Then just run "make test" which will create the libpng library in
this directory and run a quick test that reads the "pngtest.png"
file and writes a "pngout.png" file that should be identical to it.
Look for "9782 zero samples" in the output of the test.  For more
confidence, you can run another test by typing "pngtest pngnow.png"
and looking for "289 zero samples" in the output.  Also, you can
run "pngtest -m *.png" in the "contrib/pngsuite" directory and compare
your output with the result shown in contrib/pngsuite/README.

Most of the makefiles will allow you to run "make install" to
put the library in its final resting place (if you want to
do that, run "make install" in the zlib directory first if necessary).

Further information can be found in the README and libpng.txt
files, in the individual makefiles, in png.h, in the README files in
subdirectories of the LIB directory, and the manual pages libpng.3 and png.5.

--- NEW FILE: pngrio.c ---

/* pngrio.c - functions for data input
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file provides a location for all input.  Users who need
 * special handling are expected to write a function that has the same
 * arguments as this and performs a similar function, but that possibly
 * has a different input method.  Note that you shouldn't change this
 * function, but rather write a replacement function and then make
 * libpng use it at run time with png_set_read_fn(...).
 */

#define PNG_INTERNAL
#include "png.h"

/* Read the data from whatever input you are using.  The default routine
   reads from a file pointer.  Note that this routine sometimes gets called
   with very small lengths, so you should implement some kind of simple
   buffering if you are using unbuffered reads.  This should never be asked
   to read more then 64K on a 16 bit machine. */
void /* PRIVATE */
png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   png_debug1(4,"reading %d bytes\n", (int)length);
   if (png_ptr->read_data_fn != NULL)
      (*(png_ptr->read_data_fn))(png_ptr, data, length);
   else
      png_error(png_ptr, "Call to NULL read function");
}

#if !defined(PNG_NO_STDIO)
/* This is the function that does the actual reading of data.  If you are
   not reading from a standard C stream, you should create a replacement
   read_data function and use it at run time with png_set_read_fn(), rather
   than changing the library. */
#ifndef USE_FAR_KEYWORD
static void /* PRIVATE */
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   png_size_t check;

   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
    * instead of an int, which is what fread() actually returns.
    */
#if defined(_WIN32_WCE)
   if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
      check = 0;
#else
   check = (png_size_t)fread(data, (png_size_t)1, length,
      (png_FILE_p)png_ptr->io_ptr);
#endif

   if (check != length)
      png_error(png_ptr, "Read Error");
}
#else
/* this is the model-independent version. Since the standard I/O library
   can't handle far buffers in the medium and small models, we have to copy
   the data.
*/

#define NEAR_BUF_SIZE 1024
#define MIN(a,b) (a <= b ? a : b)

static void /* PRIVATE */
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   int check;
   png_byte *n_data;
   png_FILE_p io_ptr;

   /* Check if data really is near. If so, use usual code. */
   n_data = (png_byte *)CVT_PTR_NOCHECK(data);
   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
   if ((png_bytep)n_data == data)
   {
#if defined(_WIN32_WCE)
      if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
         check = 0;
#else
      check = fread(n_data, 1, length, io_ptr);
#endif
   }
   else
   {
      png_byte buf[NEAR_BUF_SIZE];
      png_size_t read, remaining, err;
      check = 0;
      remaining = length;
      do
      {
         read = MIN(NEAR_BUF_SIZE, remaining);
#if defined(_WIN32_WCE)
         if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
            err = 0;
#else
         err = fread(buf, (png_size_t)1, read, io_ptr);
#endif
         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
         if(err != read)
            break;
         else
            check += err;
         data += read;
         remaining -= read;
      }
      while (remaining != 0);
   }
   if ((png_uint_32)check != (png_uint_32)length)
      png_error(png_ptr, "read Error");
}
#endif
#endif

/* This function allows the application to supply a new input function
   for libpng if standard C streams aren't being used.

   This function takes as its arguments:
   png_ptr      - pointer to a png input data structure
   io_ptr       - pointer to user supplied structure containing info about
                  the input functions.  May be NULL.
   read_data_fn - pointer to a new input function that takes as its
                  arguments a pointer to a png_struct, a pointer to
                  a location where input data can be stored, and a 32-bit
                  unsigned int that is the number of bytes to be read.
                  To exit and output any fatal error messages the new write
                  function should call png_error(png_ptr, "Error msg"). */
void PNGAPI
png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
   png_rw_ptr read_data_fn)
{
   png_ptr->io_ptr = io_ptr;

#if !defined(PNG_NO_STDIO)
   if (read_data_fn != NULL)
      png_ptr->read_data_fn = read_data_fn;
   else
      png_ptr->read_data_fn = png_default_read_data;
#else
   png_ptr->read_data_fn = read_data_fn;
#endif

   /* It is an error to write to a read device */
   if (png_ptr->write_data_fn != NULL)
   {
      png_ptr->write_data_fn = NULL;
      png_warning(png_ptr,
         "It's an error to set both read_data_fn and write_data_fn in the ");
      png_warning(png_ptr,
         "same structure.  Resetting write_data_fn to NULL.");
   }

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
   png_ptr->output_flush_fn = NULL;
#endif
}


--- NEW FILE: pngvcrd.c ---
/* pngvcrd.c - mixed C/assembler version of utilities to read a PNG file
 *
 * For Intel x86 CPU and Microsoft Visual C++ compiler
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 Glenn Randers-Pehrson
 * Copyright (c) 1998, Intel Corporation
 *
 * Contributed by Nirav Chhatrapati, Intel Corporation, 1998
 * Interface to libpng contributed by Gilles Vollant, 1999
 * Debugging and cleanup by Greg Roelofs, 2000, 2001
 *
 * In png_do_read_interlace() in libpng versions 1.0.3a through 1.0.4d,
 * a sign error in the post-MMX cleanup code for each pixel_depth resulted
 * in bad pixels at the beginning of some rows of some images, and also
 * (due to out-of-range memory reads and writes) caused heap corruption
 * when compiled with MSVC 6.0.  The error was fixed in version 1.0.4e.
 *
[...3797 lines suppressed...]
                     p = c;
                */

               p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;

               *rp = (png_byte)(((int)(*rp) + p) & 0xff);
               rp++;
            }
         }
         break;
      }

      default:
         png_warning(png_ptr, "Ignoring bad row filter type");
         *row=0;
         break;
   }
}

#endif /* PNG_ASSEMBLER_CODE_SUPPORTED && PNG_USE_PNGVCRD */

--- NEW FILE: Y2KINFO ---
   Y2K compliance in libpng:
   =========================

      June 8, 2001

      Since the PNG Development group is an ad-hoc body, we can't make
      an official declaration.

      This is your unofficial assurance that libpng from version 0.71 and
      upward through 1.0.12 are Y2K compliant.  It is my belief that earlier
      versions were also Y2K compliant.

      Libpng only has three year fields.  One is a 2-byte unsigned integer
      that will hold years up to 65535.  The other two hold the date in text
      format, and will hold years up to 9999.

      The integer is
          "png_uint_16 year" in png_time_struct.

      The strings are
          "png_charp time_buffer" in png_struct and
          "near_time_buffer", which is a local character string in png.c.

      There are seven time-related functions:

          png_convert_to_rfc_1123() in png.c
            (formerly png_convert_to_rfc_1152() in error)
          png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
          png_convert_from_time_t() in pngwrite.c
          png_get_tIME() in pngget.c
          png_handle_tIME() in pngrutil.c, called in pngread.c
          png_set_tIME() in pngset.c
          png_write_tIME() in pngwutil.c, called in pngwrite.c

      All appear to handle dates properly in a Y2K environment.  The
      png_convert_from_time_t() function calls gmtime() to convert from system
      clock time, which returns (year - 1900), which we properly convert to
      the full 4-digit year.  There is a possibility that applications using
      libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
      function, or that they are incorrectly passing only a 2-digit year
      instead of "year - 1900" into the png_convert_from_struct_tm() function,
      but this is not under our control.  The libpng documentation has always
      stated that it works with 4-digit years, and the APIs have been
      documented as such.

      The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
      integer to hold the year, and can hold years as large as 65535.

      zlib, upon which libpng depends, is also Y2K compliant.  It contains
      no date-related code.


         Glenn Randers-Pehrson
         libpng maintainer
         PNG Development Group

--- NEW FILE: pngread.c ---

/* pngread.c - read a PNG file
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file contains routines that an application calls directly to
 * read a PNG file or stream.
 */

#define PNG_INTERNAL
#include "png.h"

/* Create a PNG structure for reading, and allocate any memory needed. */
png_structp PNGAPI
png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
[...1386 lines suppressed...]
      info_ptr->free_me |= PNG_FREE_ROWS;
#endif
      for (row = 0; row < (int)info_ptr->height; row++)
      {
         info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
            png_get_rowbytes(png_ptr, info_ptr));
      }
   }

   png_read_image(png_ptr, info_ptr->row_pointers);
   info_ptr->valid |= PNG_INFO_IDAT;

   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
   png_read_end(png_ptr, info_ptr);

   if(transforms == 0 || params == NULL)
      /* quiet compiler warnings */ return;

}
#endif

--- NEW FILE: png.h ---

/* png.h - header file for PNG reference library
 *
 * libpng version 1.0.12 - June 8, 2001
 * Copyright (c) 1998-2001 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.)
 *
 * Authors and maintainers:
 *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
 *  libpng versions 0.97, January 1998, through 1.0.12 - June 8, 2001: Glenn
 *  See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
 *
 *    Due to various miscommunications, unforeseen code incompatibilities
 *    and occasional factors outside the authors' control, version numbering
 *    on the library has not always been consistent and straightforward.
[...3049 lines suppressed...]
#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

/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */

#endif /* PNG_INTERNAL */

#ifdef __cplusplus
}
#endif

#endif /* PNG_VERSION_INFO_ONLY */
/* do not put anything past this line */
#endif /* PNG_H */

--- NEW FILE: libpng.3 ---
.TH LIBPNG 3 "June 8, 2001"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12
.SH SYNOPSIS
\fI\fB

\fB#include <png.h>\fP

\fI\fB

\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP

\fI\fB

\fBint png_check_sig (png_bytep \fP\fIsig\fP\fB, int \fInum\fP\fB);\fP

\fI\fB

\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
[...3720 lines suppressed...]
appreciated.


A "png_get_copyright" function is available, for convenient use in "about"
boxes and the like:

   printf("%s",png_get_copyright(NULL));

Also, the PNG logo (in PNG format, of course) is supplied in the
files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
certification mark of the Open Source Initiative.

Glenn Randers-Pehrson
randeg at alum.rpi.edu
June 8, 2001

.\" end of man page


--- NEW FILE: pngpread.c ---

/* pngpread.c - read a png file in push mode
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

#define PNG_INTERNAL
#include "png.h"

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

/* push model modes */
#define PNG_READ_SIG_MODE   0
#define PNG_READ_CHUNK_MODE 1
#define PNG_READ_IDAT_MODE  2
[...1465 lines suppressed...]
void PNGAPI
png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
   png_progressive_end_ptr end_fn)
{
   png_ptr->info_fn = info_fn;
   png_ptr->row_fn = row_fn;
   png_ptr->end_fn = end_fn;

   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
}

png_voidp PNGAPI
png_get_progressive_ptr(png_structp png_ptr)
{
   return png_ptr->io_ptr;
}

#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */


--- NEW FILE: Makefile ---
# makefile for libpng on Linux ELF with gcc
# Copyright (C) 1998, 1999 Greg Roelofs
# Copyright (C) 1996, 1997 Andreas Dilger
# For conditions of distribution and use, see copyright notice in png.h

#CC=gcc

# where "make install" puts libpng.a, libpng.so*, png.h and pngconf.h
prefix=/usr/local

# Where the zlib library and include files are located
#ZLIBLIB=/usr/local/lib
#ZLIBINC=/usr/local/include
ZLIBLIB=../zlib
ZLIBINC=../zlib

ALIGN=
# for i386:
#ALIGN=-malign-loops=2 -malign-functions=2

WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
	-Wmissing-declarations -Wtraditional -Wcast-align \
	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion

# for pgcc version 2.95.1, -O3 is buggy; don't use it.

CFLAGS += -I$(ZLIBINC) -Wall -O3 -funroll-loops \
	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz -lm

#RANLIB=ranlib
#RANLIB=echo

# read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
# have to change it.
PNGMAJ = 2
PNGMIN = 1.0.12
PNGVER = $(PNGMAJ).$(PNGMIN)

INCPATH=$(prefix)/include
LIBPATH=$(prefix)/lib

OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
	pngwtran.o pngmem.o pngerror.o pngpread.o

OBJSDLL = $(OBJS:.o=.pic.o)

.SUFFIXES:      .c .o .pic.o

.c.pic.o:
	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c

#all: libpng.a libpng.so pngtest
all: libpng.a libpng.so

libpng.a: $(OBJS)
	ar rc $@ $(OBJS)
	$(RANLIB) $@

libpng.so: libpng.so.$(PNGMAJ)
	ln -sf libpng.so.$(PNGMAJ) libpng.so

libpng.so.$(PNGMAJ): libpng.so.$(PNGVER)
	ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ)

libpng.so.$(PNGVER): $(OBJSDLL)
	$(CC) -shared -Wl,-soname,libpng.so.$(PNGMAJ) -o libpng.so.$(PNGVER) \
	 $(OBJSDLL) -L$(ZLIBLIB) -lz -lm -lc

pngtest: pngtest.o libpng.so
	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)

test: pngtest
	./pngtest

install: libpng.a libpng.so.$(PNGVER)
	- at if [ ! -d $(INCPATH)  ]; then mkdir $(INCPATH); fi
	- at if [ ! -d $(LIBPATH) ]; then mkdir $(LIBPATH); fi
	cp png.h pngconf.h $(INCPATH)
	chmod 644 $(INCPATH)/png.h $(INCPATH)/pngconf.h
	cp libpng.a libpng.so.$(PNGVER) $(LIBPATH)
	chmod 755 $(LIBPATH)/libpng.so.$(PNGVER)
	-@/bin/rm -f $(LIBPATH)/libpng.so.$(PNGMAJ) $(LIBPATH)/libpng.so
	(cd $(LIBPATH); ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ); \
	 ln -sf libpng.so.$(PNGMAJ) libpng.so)

romfs:
	if [ "$(CONFIG_X86)" = "y" ]; then \
		[ -d $(ROMFSDIR)/lib ] || mkdir -p $(ROMFSDIR)/lib ; \
		$(ROMFSINST) libpng.so.2 /lib/libpng.so.2 ; \
	fi

clean:
	-/bin/rm -f *.o libpng.a libpng.so* pngtest pngout.png

DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
writelock:
	chmod a-w *.[ch35] $(DOCS) scripts/*

# DO NOT DELETE THIS LINE -- make depend depends on it.

png.o png.pic.o: png.h pngconf.h
pngerror.o pngerror.pic.o: png.h pngconf.h
pngrio.o pngrio.pic.o: png.h pngconf.h
pngwio.o pngwio.pic.o: png.h pngconf.h
pngmem.o pngmem.pic.o: png.h pngconf.h
pngset.o pngset.pic.o: png.h pngconf.h
pngget.o pngget.pic.o: png.h pngconf.h
pngread.o pngread.pic.o: png.h pngconf.h
pngrtran.o pngrtran.pic.o: png.h pngconf.h
pngrutil.o pngrutil.pic.o: png.h pngconf.h
pngtrans.o pngtrans.pic.o: png.h pngconf.h
pngwrite.o pngwrite.pic.o: png.h pngconf.h
pngwtran.o pngwtran.pic.o: png.h pngconf.h
pngwutil.o pngwutil.pic.o: png.h pngconf.h
pngpread.o pngpread.pic.o: png.h pngconf.h

pngtest.o: png.h pngconf.h

--- NEW FILE: pngasmrd.h ---
/* pngasmrd.h - assembler version of utilities to read a PNG file
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 2001 Glenn Randers-Pehrson
 *
 */

/* This file is obsolete in libpng-1.0.9 and later; its contents now appear
 * at the end of pngconf.h.
 */

--- NEW FILE: pngrtran.c ---

/* pngrtran.c - transforms the data in a row for PNG readers
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file contains functions optionally called by an application
 * in order to tell libpng how to handle data when reading a PNG.
 * Transformations that are used in both reading and writing are
 * in pngtrans.c.
 */

#define PNG_INTERNAL
#include "png.h"

/* Set the action on getting a CRC error for an ancillary or critical chunk. */
[...4076 lines suppressed...]
            bytes_per_pixel = 8;
         else
            return;

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
            png_uint_32 s0=*(rp  )<<8 | *(rp+1);
            png_uint_32 s1=*(rp+2)<<8 | *(rp+3);
            png_uint_32 s2=*(rp+4)<<8 | *(rp+5);
            png_uint_32 red=(65536+s0+s1)&0xffff;
            png_uint_32 blue=(65536+s2+s1)&0xffff;
            *(rp  ) = (png_byte)((red>>8)&0xff);
            *(rp+1) = (png_byte)(red&0xff);
            *(rp+4) = (png_byte)((blue>>8)&0xff);
            *(rp+5) = (png_byte)(blue&0xff);
         }
      }
   }
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */

--- NEW FILE: png.c ---

/* png.c - location for general purpose libpng functions
 *
 * libpng version 1.0.12 - June 8, 2001
 * Copyright (c) 1998-2001 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.)
 *
 */

#define PNG_INTERNAL
#define PNG_NO_EXTERN
#include "png.h"

/* Generate a compiler error if there is an old png.h in the search path. */
typedef version_1_0_12 Your_png_h_is_not_version_1_0_12;

/* Version information for C files.  This had better match the version
 * string defined in png.h.  */

#ifdef PNG_USE_GLOBAL_ARRAYS
/* png_libpng_ver was changed to a function in version 1.0.5c */
const char png_libpng_ver[18] = "1.0.12";

/* png_sig was changed to a function in version 1.0.5c */
/* Place to hold the signature string for a PNG file. */
const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};

/* Invoke global declarations for constant strings for known chunk types */
PNG_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
PNG_bKGD;
PNG_cHRM;
PNG_gAMA;
PNG_hIST;
PNG_iCCP;
PNG_iTXt;
PNG_oFFs;
PNG_pCAL;
PNG_sCAL;
PNG_pHYs;
PNG_sBIT;
PNG_sPLT;
PNG_sRGB;
PNG_tEXt;
PNG_tIME;
PNG_tRNS;
PNG_zTXt;

/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */

/* start of interlace block */
const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};

/* offset to next interlace block */
const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};

/* start of interlace block in the y direction */
const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};

/* offset to next interlace block in the y direction */
const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};

/* width of interlace block (used in assembler routines only) */
#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
#endif

/* Height of interlace block.  This is not currently used - if you need
 * it, uncomment it here and in png.h
const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/

/* Mask to determine which pixels are valid in a pass */
const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};

/* Mask to determine which pixels to overwrite while displaying */
const int FARDATA png_pass_dsp_mask[]
   = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};

#endif

/* Tells libpng that we have already handled the first "num_bytes" bytes
 * of the PNG file signature.  If the PNG data is embedded into another
 * stream we can set num_bytes = 8 so that libpng will not attempt to read
 * or write any of the magic bytes before it starts on the IHDR.
 */

void PNGAPI
png_set_sig_bytes(png_structp png_ptr, int num_bytes)
{
   png_debug(1, "in png_set_sig_bytes\n");
   if (num_bytes > 8)
      png_error(png_ptr, "Too many bytes for PNG signature.");

   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
}

/* Checks whether the supplied bytes match the PNG signature.  We allow
 * checking less than the full 8-byte signature so that those apps that
 * already read the first few bytes of a file to determine the file type
 * can simply check the remaining bytes for extra assurance.  Returns
 * an integer less than, equal to, or greater than zero if sig is found,
 * respectively, to be less than, to match, or be greater than the correct
 * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
 */
int PNGAPI
png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
{
   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
   if (num_to_check > 8)
      num_to_check = 8;
   else if (num_to_check < 1)
      return (0);

   if (start > 7)
      return (0);

   if (start + num_to_check > 8)
      num_to_check = 8 - start;

   return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
}

/* (Obsolete) function to check signature bytes.  It does not allow one
 * to check a partial signature.  This function might be removed in the
 * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
 */
int PNGAPI
png_check_sig(png_bytep sig, int num)
{
  return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
}

/* Function to allocate memory for zlib and clear it to 0. */
voidpf /* PRIVATE */
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
   png_uint_32 num_bytes = (png_uint_32)items * size;
   png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);

#ifndef PNG_NO_ZALLOC_ZERO
   if (num_bytes > (png_uint_32)0x8000L)
   {
      png_memset(ptr, 0, (png_size_t)0x8000L);
      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
   }
   else
   {
      png_memset(ptr, 0, (png_size_t)num_bytes);
   }
#endif
   return ((voidpf)ptr);
}

/* function to free memory for zlib */
void /* PRIVATE */
png_zfree(voidpf png_ptr, voidpf ptr)
{
   png_free((png_structp)png_ptr, (png_voidp)ptr);
}

/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
 * in case CRC is > 32 bits to leave the top bits 0.
 */
void /* PRIVATE */
png_reset_crc(png_structp png_ptr)
{
   png_ptr->crc = crc32(0, Z_NULL, 0);
}

/* Calculate the CRC over a section of data.  We can only pass as
 * much data to this routine as the largest single buffer size.  We
 * also check that this data will actually be used before going to the
 * trouble of calculating it.
 */
void /* PRIVATE */
png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
{
   int need_crc = 1;

   if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
   {
      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
         need_crc = 0;
   }
   else                                                    /* critical */
   {
      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
         need_crc = 0;
   }

   if (need_crc)
      png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
}

/* Allocate the memory for an info_struct for the application.  We don't
 * really need the png_ptr, but it could potentially be useful in the
 * future.  This should be used in favour of malloc(sizeof(png_info))
 * and png_info_init() so that applications that want to use a shared
 * libpng don't have to be recompiled if png_info changes size.
 */
png_infop PNGAPI
png_create_info_struct(png_structp png_ptr)
{
   png_infop info_ptr;

   png_debug(1, "in png_create_info_struct\n");
   if(png_ptr == NULL) return (NULL);
#ifdef PNG_USER_MEM_SUPPORTED
   if ((info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
      png_ptr->malloc_fn, png_ptr->mem_ptr)) != NULL)
#else
   if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
#endif
   {
      png_info_init_3(&info_ptr, sizeof(png_info));
   }

   return (info_ptr);
}

/* This function frees the memory associated with a single info struct.
 * Normally, one would use either png_destroy_read_struct() or
 * png_destroy_write_struct() to free an info struct, but this may be
 * useful for some applications.
 */
void PNGAPI
png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
{
   png_infop info_ptr = NULL;

   png_debug(1, "in png_destroy_info_struct\n");
   if (info_ptr_ptr != NULL)
      info_ptr = *info_ptr_ptr;

   if (info_ptr != NULL)
   {
      png_info_destroy(png_ptr, info_ptr);

#ifdef PNG_USER_MEM_SUPPORTED
      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
          png_ptr->mem_ptr);
#else
      png_destroy_struct((png_voidp)info_ptr);
#endif
      *info_ptr_ptr = (png_infop)NULL;
   }
}

/* Initialize the info structure.  This is now an internal function (0.89)
 * and applications using it are urged to use png_create_info_struct()
 * instead.
 */
#undef png_info_init
void PNGAPI
png_info_init(png_infop info_ptr)
{
   /* We only come here via pre-1.0.12-compiled applications */
   png_info_init_3(&info_ptr, 0);
}

void PNGAPI
png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
{
   png_infop info_ptr = *ptr_ptr;

   png_debug(1, "in png_info_init_3\n");

   if(sizeof(png_info) > png_info_struct_size)
     {
       png_destroy_struct(info_ptr);
       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
       *ptr_ptr = info_ptr;
     }

   /* set everything to 0 */
   png_memset(info_ptr, 0, sizeof (png_info));
}

#ifdef PNG_FREE_ME_SUPPORTED
void PNGAPI
png_data_freer(png_structp png_ptr, png_infop info_ptr,
   int freer, png_uint_32 mask)
{
   png_debug(1, "in png_data_freer\n");
   if (png_ptr == NULL || info_ptr == NULL)
      return;
   if(freer == PNG_DESTROY_WILL_FREE_DATA)
      info_ptr->free_me |= mask;
   else if(freer == PNG_USER_WILL_FREE_DATA)
      info_ptr->free_me &= ~mask;
   else
      png_warning(png_ptr,
         "Unknown freer parameter in png_data_freer.");
}
#endif

void PNGAPI
png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
   int num)
{
   png_debug(1, "in png_free_data\n");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

#if defined(PNG_TEXT_SUPPORTED)
/* free text item num or (if num == -1) all text items */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
#else
if (mask & PNG_FREE_TEXT)
#endif
{
   if (num != -1)
   {
     if (info_ptr->text && info_ptr->text[num].key)
     {
         png_free(png_ptr, info_ptr->text[num].key);
         info_ptr->text[num].key = NULL;
     }
   }
   else
   {
       int i;
       for (i = 0; i < info_ptr->num_text; i++)
           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
       png_free(png_ptr, info_ptr->text);
       info_ptr->text = NULL;
       info_ptr->num_text=0;
   }
}
#endif

#if defined(PNG_tRNS_SUPPORTED)
/* free any tRNS entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
#else
if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
#endif
{
    png_free(png_ptr, info_ptr->trans);
    info_ptr->valid &= ~PNG_INFO_tRNS;
    info_ptr->trans = NULL;
}
#endif

#if defined(PNG_sCAL_SUPPORTED)
/* free any sCAL entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
#else
if (mask & PNG_FREE_SCAL)
#endif
{
#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
    png_free(png_ptr, info_ptr->scal_s_width);
    png_free(png_ptr, info_ptr->scal_s_height);
    info_ptr->scal_s_width = NULL;
    info_ptr->scal_s_height = NULL;
#endif
    info_ptr->valid &= ~PNG_INFO_sCAL;
}
#endif

#if defined(PNG_pCAL_SUPPORTED)
/* free any pCAL entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
#else
if (mask & PNG_FREE_PCAL)
#endif
{
    png_free(png_ptr, info_ptr->pcal_purpose);
    png_free(png_ptr, info_ptr->pcal_units);
    info_ptr->pcal_purpose = NULL;
    info_ptr->pcal_units = NULL;
    if (info_ptr->pcal_params != NULL)
    {
        int i;
        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
        {
          png_free(png_ptr, info_ptr->pcal_params[i]);
          info_ptr->pcal_params[i]=NULL;
        }
        png_free(png_ptr, info_ptr->pcal_params);
        info_ptr->pcal_params = NULL;
    }
    info_ptr->valid &= ~PNG_INFO_pCAL;
}
#endif

#if defined(PNG_iCCP_SUPPORTED)
/* free any iCCP entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
#else
if (mask & PNG_FREE_ICCP)
#endif
{
    png_free(png_ptr, info_ptr->iccp_name);
    png_free(png_ptr, info_ptr->iccp_profile);
    info_ptr->iccp_name = NULL;
    info_ptr->iccp_profile = NULL;
    info_ptr->valid &= ~PNG_INFO_iCCP;
}
#endif

#if defined(PNG_sPLT_SUPPORTED)
/* free a given sPLT entry, or (if num == -1) all sPLT entries */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
#else
if (mask & PNG_FREE_SPLT)
#endif
{
   if (num != -1)
   {
      if(info_ptr->splt_palettes)
      {
          png_free(png_ptr, info_ptr->splt_palettes[num].name);
          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
          info_ptr->splt_palettes[num].name = NULL;
          info_ptr->splt_palettes[num].entries = NULL;
      }
   }
   else
   {
       if(info_ptr->splt_palettes_num)
       {
         int i;
         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);

         png_free(png_ptr, info_ptr->splt_palettes);
         info_ptr->splt_palettes = NULL;
         info_ptr->splt_palettes_num = 0;
       }
       info_ptr->valid &= ~PNG_INFO_sPLT;
   }
}
#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
#else
if (mask & PNG_FREE_UNKN)
#endif
{
   if (num != -1)
   {
       if(info_ptr->unknown_chunks)
       {
          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
          info_ptr->unknown_chunks[num].data = NULL;
       }
   }
   else
   {
       int i;

       if(info_ptr->unknown_chunks_num)
       {
         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);

         png_free(png_ptr, info_ptr->unknown_chunks);
         info_ptr->unknown_chunks = NULL;
         info_ptr->unknown_chunks_num = 0;
       }
   }
}
#endif

#if defined(PNG_hIST_SUPPORTED)
/* free any hIST entry */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
#else
if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
#endif
{
    png_free(png_ptr, info_ptr->hist);
    info_ptr->hist = NULL;
    info_ptr->valid &= ~PNG_INFO_hIST;
}
#endif

/* free any PLTE entry that was internally allocated */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
#else
if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
#endif
{
    png_zfree(png_ptr, info_ptr->palette);
    info_ptr->palette = NULL;
    info_ptr->valid &= ~PNG_INFO_PLTE;
    info_ptr->num_palette = 0;
}

#if defined(PNG_INFO_IMAGE_SUPPORTED)
/* free any image bits attached to the info structure */
#ifdef PNG_FREE_ME_SUPPORTED
if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
#else
if (mask & PNG_FREE_ROWS)
#endif
{
    if(info_ptr->row_pointers)
    {
       int row;
       for (row = 0; row < (int)info_ptr->height; row++)
       {
          png_free(png_ptr, info_ptr->row_pointers[row]);
          info_ptr->row_pointers[row]=NULL;
       }
       png_free(png_ptr, info_ptr->row_pointers);
       info_ptr->row_pointers=NULL;
    }
    info_ptr->valid &= ~PNG_INFO_IDAT;
}
#endif

#ifdef PNG_FREE_ME_SUPPORTED
   if(num == -1)
     info_ptr->free_me &= ~mask;
   else
     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
#endif
}

/* This is an internal routine to free any memory that the info struct is
 * pointing to before re-using it or freeing the struct itself.  Recall
 * that png_free() checks for NULL pointers for us.
 */
void /* PRIVATE */
png_info_destroy(png_structp png_ptr, png_infop info_ptr)
{
   png_debug(1, "in png_info_destroy\n");

   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   if (png_ptr->num_chunk_list)
   {
       png_free(png_ptr, png_ptr->chunk_list);
       png_ptr->chunk_list=NULL;
       png_ptr->num_chunk_list=0;
   }
#endif

   png_info_init_3(&info_ptr, sizeof(png_info));
}

/* This function returns a pointer to the io_ptr associated with the user
 * functions.  The application should free any memory associated with this
 * pointer before png_write_destroy() or png_read_destroy() are called.
 */
png_voidp PNGAPI
png_get_io_ptr(png_structp png_ptr)
{
   return (png_ptr->io_ptr);
}

#if !defined(PNG_NO_STDIO)
/* Initialize the default input/output functions for the PNG file.  If you
 * use your own read or write routines, you can call either png_set_read_fn()
 * or png_set_write_fn() instead of png_init_io().  If you have defined
 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
 * necessarily available.
 */
void PNGAPI
png_init_io(png_structp png_ptr, png_FILE_p fp)
{
   png_debug(1, "in png_init_io\n");
   png_ptr->io_ptr = (png_voidp)fp;
}
#endif

#if defined(PNG_TIME_RFC1123_SUPPORTED)
/* Convert the supplied time into an RFC 1123 string suitable for use in
 * a "Creation Time" or other text-based time string.
 */
png_charp PNGAPI
png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
{
   static PNG_CONST char short_months[12][4] =
        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

   if (png_ptr->time_buffer == NULL)
   {
      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
         sizeof(char)));
   }

#if defined(_WIN32_WCE)
   {
      wchar_t time_buf[29];
      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
          ptime->day % 32, short_months[(ptime->month - 1) % 12],
        ptime->year, ptime->hour % 24, ptime->minute % 60,
          ptime->second % 61);
      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
          NULL, NULL);
   }
#else
#ifdef USE_FAR_KEYWORD
   {
      char near_time_buf[29];
      sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
          ptime->day % 32, short_months[(ptime->month - 1) % 12],
          ptime->year, ptime->hour % 24, ptime->minute % 60,
          ptime->second % 61);
      png_memcpy(png_ptr->time_buffer, near_time_buf,
          29*sizeof(char));
   }
#else
   sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
       ptime->day % 32, short_months[(ptime->month - 1) % 12],
       ptime->year, ptime->hour % 24, ptime->minute % 60,
       ptime->second % 61);
#endif
#endif /* _WIN32_WCE */
   return ((png_charp)png_ptr->time_buffer);
}
#endif /* PNG_TIME_RFC1123_SUPPORTED */

#if 0
/* Signature string for a PNG file. */
png_bytep PNGAPI
png_sig_bytes(void)
{
   return ((png_bytep)"\211\120\116\107\015\012\032\012");
}
#endif

png_charp PNGAPI
png_get_copyright(png_structp png_ptr)
{
   if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
   return ((png_charp) "\n libpng version 1.0.12 - June 8, 2001\n\
   Copyright (c) 1998-2001 Glenn Randers-Pehrson\n\
   Copyright (c) 1996, 1997 Andreas Dilger\n\
   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n");
   return ((png_charp) "");
}

/* The following return the library version as a short string in the
 * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
 * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
 * in png.h.
 */

png_charp PNGAPI
png_get_libpng_ver(png_structp png_ptr)
{
   /* Version of *.c files used when building libpng */
   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
      return((png_charp) "1.0.12");
   return((png_charp) "1.0.12");
}

png_charp PNGAPI
png_get_header_ver(png_structp png_ptr)
{
   /* Version of *.h files used when building libpng */
   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
      return((png_charp) PNG_LIBPNG_VER_STRING);
   return((png_charp) PNG_LIBPNG_VER_STRING);
}

png_charp PNGAPI
png_get_header_version(png_structp png_ptr)
{
   /* Returns longer string containing both version and date */
   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
      return((png_charp) PNG_HEADER_VERSION_STRING);
   return((png_charp) PNG_HEADER_VERSION_STRING);
}

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int /* PRIVATE */
png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
{
   /* check chunk_name and return "keep" value if it's on the list, else 0 */
   int i;
   png_bytep p;
   if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
      return 0;
   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
      if (!png_memcmp(chunk_name, p, 4))
        return ((int)*(p+4));
   return 0;
}
#endif

/* This function, added to libpng-1.0.6g, is untested. */
int PNGAPI
png_reset_zstream(png_structp png_ptr)
{
   return (inflateReset(&png_ptr->zstream));
}

/* This function was added to libpng-1.0.7 */
png_uint_32 PNGAPI
png_access_version_number(void)
{
   /* Version of *.c files used when building libpng */
   return((png_uint_32) 10012L);
}

/* this function was added to libpng 1.2.0 */
#if !defined(PNG_USE_PNGGCCRD) && \
    !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
int PNGAPI
png_mmx_support(void)
{
    return -1;
}
#endif

--- NEW FILE: KNOWNBUG ---

Known bugs in libpng-1.0.12

1. April 22, 2001: pnggccrd.c has been reported to crash on NetBSD when
   reading interlaced PNG files, when assembler code is enabled.

   STATUS: Under investigation.

--- NEW FILE: pngerror.c ---

/* pngerror.c - stub functions for i/o and memory allocation
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file provides a location for all error handling.  Users who
 * need special error handling are expected to write replacement functions
 * and use png_set_error_fn() to use those functions.  See the instructions
 * at each function.
 */

#define PNG_INTERNAL
#include "png.h"

static void /* PRIVATE */
png_default_error PNGARG((png_structp png_ptr,
                                      png_const_charp message));
static void /* PRIVATE */
png_default_warning PNGARG((png_structp png_ptr,
                                        png_const_charp message));

/* This function is called whenever there is a fatal error.  This function
 * should not be changed.  If there is a need to handle errors differently,
 * you should supply a replacement error function and use png_set_error_fn()
 * to replace the error function at run-time.
 */
void PNGAPI
png_error(png_structp png_ptr, png_const_charp message)
{
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
   char msg[16];
   if (png_ptr->flags&(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
   {
     int offset = 0;
     if (*message == '#')
     {
         for (offset=1; offset<15; offset++)
            if (*(message+offset) == ' ')
                break;
         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
         {
            int i;
            for (i=0; i<offset-1; i++)
               msg[i]=message[i+1];
            msg[i]='\0';
            message=msg;
         }
         else
            message+=offset;
     }
     else
     {
         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
         {
            msg[0]='0';        
            msg[1]='\0';
            message=msg;
         }
     }
   }
#endif
   if (png_ptr->error_fn != NULL)
      (*(png_ptr->error_fn))(png_ptr, message);

   /* if the following returns or doesn't exist, use the default function,
      which will not return */
   png_default_error(png_ptr, message);
}

/* This function is called whenever there is a non-fatal error.  This function
 * should not be changed.  If there is a need to handle warnings differently,
 * you should supply a replacement warning function and use
 * png_set_error_fn() to replace the warning function at run-time.
 */
void PNGAPI
png_warning(png_structp png_ptr, png_const_charp message)
{
     int offset = 0;
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
   if (png_ptr->flags&(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
#endif
   {
     if (*message == '#')
     {
         for (offset=1; offset<15; offset++)
            if (*(message+offset) == ' ')
                break;
     }
   }
   if (png_ptr->warning_fn != NULL)
      (*(png_ptr->warning_fn))(png_ptr, (png_const_charp)(message+offset));
   else
      png_default_warning(png_ptr, (png_const_charp)(message+offset));
}

/* These utilities are used internally to build an error message that relates
 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
 * this is used to prefix the message.  The message is limited in length
 * to 63 bytes, the name characters are output as hex digits wrapped in []
 * if the character is invalid.
 */
#define isnonalpha(c) ((c) < 41 || (c) > 122 || ((c) > 90 && (c) < 97))
static PNG_CONST char png_digit[16] = {
   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E',
   'F' };

static void /* PRIVATE */
png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
   message)
{
   int iout = 0, iin = 0;

   while (iin < 4)
   {
      int c = png_ptr->chunk_name[iin++];
      if (isnonalpha(c))
      {
         buffer[iout++] = '[';
         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
         buffer[iout++] = png_digit[c & 0x0f];
         buffer[iout++] = ']';
      }
      else
      {
         buffer[iout++] = (png_byte)c;
      }
   }

   if (message == NULL)
      buffer[iout] = 0;
   else
   {
      buffer[iout++] = ':';
      buffer[iout++] = ' ';
      png_memcpy(buffer+iout, message, 64);
      buffer[iout+63] = 0;
   }
}

void PNGAPI
png_chunk_error(png_structp png_ptr, png_const_charp message)
{
   char msg[18+64];
   png_format_buffer(png_ptr, msg, message);
   png_error(png_ptr, msg);
}

void PNGAPI
png_chunk_warning(png_structp png_ptr, png_const_charp message)
{
   char msg[18+64];
   png_format_buffer(png_ptr, msg, message);
   png_warning(png_ptr, msg);
}

/* This is the default error handling function.  Note that replacements for
 * this function MUST NOT RETURN, or the program will likely crash.  This
 * function is used by default, or if the program supplies NULL for the
 * error function pointer in png_set_error_fn().
 */
static void /* PRIVATE */
png_default_error(png_structp png_ptr, png_const_charp message)
{
#ifndef PNG_NO_CONSOLE_IO
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
   if (*message == '#')
   {
     int offset;
     char error_number[16];
     for (offset=0; offset<15; offset++)
     {
         error_number[offset] = *(message+offset+1);
         if (*(message+offset) == ' ')
             break;
     }
     if((offset > 1) && (offset < 15))
     {
       error_number[offset-1]='\0';
       fprintf(stderr, "libpng error no. %s: %s\n", error_number, message+offset);
     }
     else
       fprintf(stderr, "libpng error: %s, offset=%d\n", message,offset);
   }
   else
#endif
   fprintf(stderr, "libpng error: %s\n", message);
#else
   if (message)
     /* make compiler happy */ ;
#endif

#ifdef PNG_SETJMP_SUPPORTED
#  ifdef USE_FAR_KEYWORD
   {
      jmp_buf jmpbuf;
      png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
      longjmp(jmpbuf, 1);
   }
#  else
   longjmp(png_ptr->jmpbuf, 1);
# endif
#else
   if (png_ptr)
     /* make compiler happy */ ;
   PNG_ABORT();
#endif
}

/* This function is called when there is a warning, but the library thinks
 * it can continue anyway.  Replacement functions don't have to do anything
 * here if you don't want them to.  In the default configuration, png_ptr is
 * not used, but it is passed in case it may be useful.
 */
static void /* PRIVATE */
png_default_warning(png_structp png_ptr, png_const_charp message)
{
#ifndef PNG_NO_CONSOLE_IO
#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
   if (*message == '#')
   {
     int offset;
     char warning_number[16];
     for (offset=0; offset<15; offset++)
     {
        warning_number[offset]=*(message+offset+1);
        if (*(message+offset) == ' ')
            break;
     }
     if((offset > 1) && (offset < 15))
     {
       warning_number[offset-1]='\0';
       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
          message+offset);
     }
     else
       fprintf(stderr, "libpng warning: %s\n", message);
   }
   else
#  endif
     fprintf(stderr, "libpng warning: %s\n", message);
#else
   if (message)
     /* appease compiler */ ;
#endif
   if (png_ptr)
      return;
}

/* This function is called when the application wants to use another method
 * of handling errors and warnings.  Note that the error function MUST NOT
 * return to the calling routine or serious problems will occur.  The return
 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
 */
void PNGAPI
png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warning_fn)
{
   png_ptr->error_ptr = error_ptr;
   png_ptr->error_fn = error_fn;
   png_ptr->warning_fn = warning_fn;
}


/* This function returns a pointer to the error_ptr associated with the user
 * functions.  The application should free any memory associated with this
 * pointer before png_write_destroy and png_read_destroy are called.
 */
png_voidp PNGAPI
png_get_error_ptr(png_structp png_ptr)
{
   return ((png_voidp)png_ptr->error_ptr);
}


#ifdef PNG_ERROR_NUMBERS_SUPPORTED
void
png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
{
   if(png_ptr != NULL)
   {
     png_ptr->flags &=
       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
   }
}
#endif


--- NEW FILE: pnggccrd.c ---
/* pnggccrd.c - mixed C/assembler version of utilities to read a PNG file
 *
 * For Intel x86 CPU (Pentium-MMX or later) and GNU C compiler.
 *
 *     See http://www.intel.com/drg/pentiumII/appnotes/916/916.htm
 *     and http://www.intel.com/drg/pentiumII/appnotes/923/923.htm
 *     for Intel's performance analysis of the MMX vs. non-MMX code.
 *
 * libpng version 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 Glenn Randers-Pehrson
 * Copyright (c) 1998, Intel Corporation
 *
 * Based on MSVC code contributed by Nirav Chhatrapati, Intel Corp., 1998.
 * Interface to libpng contributed by Gilles Vollant, 1999.
 * GNU C port by Greg Roelofs, 1999-2001.
 *
 * Lines 2350-4300 converted in place with intel2gas 1.3.1:
 *
[...5169 lines suppressed...]
//      "ret                  \n\t"  // DONE:  no MMX support
                                     // (fall through to standard C "ret")

        :                            // output list (none)

        :                            // any variables used on input (none)

        : "%eax"                     // clobber list
//      , "%ebx", "%ecx", "%edx"     // GRR:  we handle these manually
//      , "memory"   // if write to a variable gcc thought was in a reg
//      , "cc"       // "condition codes" (flag bits)
    );
#else     
    _mmx_supported = 0;
#endif /* PNG_MMX_CODE_SUPPORTED */

    return _mmx_supported;
}

#endif /* PNG_USE_PNGGCCRD */

--- NEW FILE: pngconf.h ---
/* pngconf.h - machine configurable file for libpng
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

/* Any machine specific code is near the front of this file, so if you
 * are configuring libpng for a machine, you may want to read the section
 * starting here down to where it starts to typedef png_color, png_text,
 * and png_info.
 */

#ifndef PNGCONF_H
#define PNGCONF_H

/* This is the size of the compression buffer, and thus the size of
[...1297 lines suppressed...]
#  define PNG_HAVE_ASSEMBLER_READ_INTERLACE
#  define PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
#endif

/* Set this in the makefile for gcc/as on Pentium, not here. */
/* Platform must be Pentium.  Makefile must assemble and load pnggccrd.c .
 * MMX will be detected at run time and used if present.
 */
#ifdef PNG_USE_PNGGCCRD
#  define PNG_HAVE_ASSEMBLER_COMBINE_ROW
#  define PNG_HAVE_ASSEMBLER_READ_INTERLACE
#  define PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
#endif
/* - see pnggccrd.c for info about what is currently enabled */

#endif /* PNG_INTERNAL */
#endif /* PNG_READ_SUPPORTED */

#endif /* PNGCONF_H */


--- NEW FILE: pngbar.jpg ---
(This appears to be a binary file; contents omitted.)

--- NEW FILE: pngnow.png ---
(This appears to be a binary file; contents omitted.)

--- NEW FILE: LICENSE ---

This copy of the libpng notices is provided for your convenience.  In case of
any discrepancy between this copy and the notices in the file png.h that is
included in the libpng distribution, the latter shall prevail.

COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:

If you modify libpng you may insert additional notices immediately following
this sentence.

libpng versions 1.0.7, July 1, 2000, through 1.0.12, June 8, 2001, are
Copyright (c) 2000, 2001 Glenn Randers-Pehrson
and are distributed according to the same disclaimer and license as libpng-1.0.6
with the following individuals added to the list of Contributing Authors

   Simon-Pierre Cadieux
   Eric S. Raymond
   Gilles Vollant

and with the following additions to the disclaimer:

   There is no warranty against interference with your enjoyment of the
   library or against infringement.  There is no warranty that our
   efforts or the library will fulfill any of your particular purposes
   or needs.  This library is provided with all faults, and the entire
   risk of satisfactory quality, performance, accuracy, and effort is with
   the user.

libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-0.96,
with the following individuals added to the list of Contributing Authors:

   Tom Lane
   Glenn Randers-Pehrson
   Willem van Schaik

libpng versions 0.89, June 1996, through 0.96, May 1997, are
Copyright (c) 1996, 1997 Andreas Dilger
Distributed according to the same disclaimer and license as libpng-0.88,
with the following individuals added to the list of Contributing Authors:

   John Bowler
   Kevin Bracey
   Sam Bushell
   Magnus Holmgren
   Greg Roelofs
   Tom Tanner

libpng versions 0.5, May 1995, through 0.88, January 1996, are
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.

For the purposes of this copyright and license, "Contributing Authors"
is defined as the following set of individuals:

   Andreas Dilger
   Dave Martindale
   Guy Eric Schalnat
   Paul Schmidt
   Tim Wegner

The PNG Reference Library is supplied "AS IS".  The Contributing Authors
and Group 42, Inc. disclaim all warranties, expressed or implied,
including, without limitation, the warranties of merchantability and of
fitness for any purpose.  The Contributing Authors and Group 42, Inc.
assume no liability for direct, indirect, incidental, special, exemplary,
or consequential damages, which may result from the use of the PNG
Reference Library, even if advised of the possibility of such damage.

Permission is hereby granted to use, copy, modify, and distribute this
source code, or portions hereof, for any purpose, without fee, subject
to the following restrictions:

1. The origin of this source code must not be misrepresented.

2. Altered versions must be plainly marked as such and
   must not be misrepresented as being the original source.

3. This Copyright notice may not be removed or altered from
   any source or altered source distribution.

The Contributing Authors and Group 42, Inc. specifically permit, without
fee, and encourage the use of this source code as a component to
supporting the PNG file format in commercial products.  If you use this
source code in a product, acknowledgment is not required but would be
appreciated.


A "png_get_copyright" function is available, for convenient use in "about"
boxes and the like:

   printf("%s",png_get_copyright(NULL));

Also, the PNG logo (in PNG format, of course) is supplied in the
files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
certification mark of the Open Source Initiative.

Glenn Randers-Pehrson
randeg at alum.rpi.edu
June 8, 2001

--- NEW FILE: configure ---
echo "
  There is no \"configure\" script for Libpng-1.0.12.  Instead, please
  copy the appropriate makefile for your system from the \"scripts\"
  directory.  Read the INSTALL file for more details.
"


--- NEW FILE: png.5 ---
.TH PNG 5 "June 8, 2001"
.SH NAME
png \- Portable Network Graphics (PNG) format
.SH DESCRIPTION
PNG (Portable Network Graphics) is an extensible file format for the
lossless, portable, well-compressed storage of raster images. PNG provides
a patent-free replacement for GIF and can also replace many
common uses of TIFF. Indexed-color, grayscale, and truecolor images are
supported, plus an optional alpha channel. Sample depths range from
1 to 16 bits.
.br

PNG is designed to work well in online viewing applications, such as the
World Wide Web, so it is fully streamable with a progressive display
option. PNG is robust, providing both full file integrity checking and
fast, simple detection of common transmission errors. Also, PNG can store
gamma and chromaticity data for improved color matching on heterogeneous
platforms.

.SH "SEE ALSO"
.IR libpng(3), zlib(3), deflate(5), and zlib(5)
.LP
PNG 1.2 specification, July 1999:
.IP
.br
http://www.libpng.org/pub/png
.br
or ftp://ftp.uu.net/graphics/png/documents
.LP
PNG 1.0 specification, October 1996:
.IP
.br
RFC 2083
.IP
.br
ftp://ds.internic.net/rfc/rfc2083.txt
.br
or (as a W3C Recommendation) at
.br
http://www.w3.org/TR/REC-png.html
.SH AUTHORS
This man page: Glenn Randers-Pehrson
.LP
Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
Glenn Randers-Pehrson and others (png-list at ccrc.wustl.edu).
.LP
Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
Thomas Boutell and others (png-list at ccrc.wustl.edu).
.LP


.SH COPYRIGHT NOTICE
The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson.
See the specification for conditions of use and distribution.
.LP
The PNG-1.0 specification is copyright (c) 1996 Massachussets Institute of
Technology.  See the specification for conditions of use and distribution.
.LP
.\" end of man page


--- NEW FILE: TODO ---
TODO - list of things to do for libpng:

Final bug fixes.
Improve API by hiding the png_struct and png_info structs.
Finish work on the no-floating-point version (including gamma compensation)
Better C++ wrapper/full C++ implementation?
Fix problem with C++ and EXTERN "C".
cHRM transformation.
Improve setjmp/longjmp usage or remove it in favor of returning error codes.
Add "grayscale->palette" transformation and "palette->grayscale" detection.
Improved dithering.
Multi-lingual error and warning message support.
Complete sRGB transformation (presently it simply uses gamma=0.45455).
Man pages for function calls.
Better documentation.
Better filter selection
   (counting huffman bits/precompression?  filter inertia?  filter costs?).
Histogram creation.
Text conversion between different code pages (Latin-1 -> Mac and DOS).
Should we always malloc 2^bit_depth PLTE/tRNS/hIST entries for safety?
Build gamma tables using fixed point (and do away with floating point entirely).
Use greater precision when changing to linear gamma for compositing against
  background and doing rgb-to-gray transformation.
Investigate pre-incremented loop counters and other loop constructions.

--- NEW FILE: pngtest.png ---
(This appears to be a binary file; contents omitted.)

--- NEW FILE: libpng.txt ---
libpng.txt - A description on how to use and modify libpng

 libpng version 1.0.12 - June 8, 2001
 Updated and distributed by Glenn Randers-Pehrson
 <randeg at alum.rpi.edu>
 Copyright (c) 1998-2001 Glenn Randers-Pehrson
 For conditions of distribution and use, see copyright
 notice in png.h.

 based on:

 libpng 1.0 beta 6  version 0.96 May 28, 1997
 Updated and distributed by Andreas Dilger
 Copyright (c) 1996, 1997 Andreas Dilger

 libpng 1.0 beta 2 - version 0.88  January 26, 1996
 For conditions of distribution and use, see copyright
 notice in png.h. Copyright (c) 1995, 1996 Guy Eric
 Schalnat, Group 42, Inc.
[...2737 lines suppressed...]
png_convert_from_time_t() function calls gmtime() to convert from system
clock time, which returns (year - 1900), which we properly convert to
the full 4-digit year.  There is a possibility that applications using
libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
function, or that they are incorrectly passing only a 2-digit year
instead of "year - 1900" into the png_convert_from_struct_tm() function,
but this is not under our control.  The libpng documentation has always
stated that it works with 4-digit years, and the APIs have been
documented as such.

The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
integer to hold the year, and can hold years as large as 65535.

zlib, upon which libpng depends, is also Y2K compliant.  It contains
no date-related code.


   Glenn Randers-Pehrson
   libpng maintainer
   PNG Development Group

--- NEW FILE: pngbar.png ---
(This appears to be a binary file; contents omitted.)

--- NEW FILE: pngwtran.c ---

/* pngwtran.c - transforms the data in a row for PNG writers
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

#define PNG_INTERNAL
#include "png.h"
#ifdef PNG_WRITE_SUPPORTED

/* Transform the data according to the user's wishes.  The order of
 * transformations is significant.
 */
void /* PRIVATE */
png_do_write_transformations(png_structp png_ptr)
{
   png_debug(1, "in png_do_write_transformations\n");

   if (png_ptr == NULL)
      return;

#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   if (png_ptr->transformations & PNG_USER_TRANSFORM)
      if(png_ptr->write_user_transform_fn != NULL)
        (*(png_ptr->write_user_transform_fn)) /* user write transform function */
          (png_ptr,                    /* png_ptr */
           &(png_ptr->row_info),       /* row_info:     */
             /*  png_uint_32 width;          width of row */
             /*  png_uint_32 rowbytes;       number of bytes in row */
             /*  png_byte color_type;        color type of pixels */
             /*  png_byte bit_depth;         bit depth of samples */
             /*  png_byte channels;          number of channels (1-4) */
             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
           png_ptr->row_buf + 1);      /* start of pixel data for row */
#endif
#if defined(PNG_WRITE_FILLER_SUPPORTED)
   if (png_ptr->transformations & PNG_FILLER)
      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
         png_ptr->flags);
#endif
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_PACKSWAP)
      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_PACK_SUPPORTED)
   if (png_ptr->transformations & PNG_PACK)
      png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
         (png_uint_32)png_ptr->bit_depth);
#endif
#if defined(PNG_WRITE_SWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_SWAP_BYTES)
      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_SHIFT_SUPPORTED)
   if (png_ptr->transformations & PNG_SHIFT)
      png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
         &(png_ptr->shift));
#endif
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_INVERT_ALPHA)
      png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
   if (png_ptr->transformations & PNG_SWAP_ALPHA)
      png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_BGR_SUPPORTED)
   if (png_ptr->transformations & PNG_BGR)
      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_INVERT_SUPPORTED)
   if (png_ptr->transformations & PNG_INVERT_MONO)
      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
}

#if defined(PNG_WRITE_PACK_SUPPORTED)
/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
 * row_info bit depth should be 8 (one pixel per byte).  The channels
 * should be 1 (this only happens on grayscale and paletted images).
 */
void /* PRIVATE */
png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
{
   png_debug(1, "in png_do_pack\n");
   if (row_info->bit_depth == 8 &&
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
      row_info->channels == 1)
   {
      switch ((int)bit_depth)
      {
         case 1:
         {
            png_bytep sp, dp;
            int mask, v;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            sp = row;
            dp = row;
            mask = 0x80;
            v = 0;

            for (i = 0; i < row_width; i++)
            {
               if (*sp != 0)
                  v |= mask;
               sp++;
               if (mask > 1)
                  mask >>= 1;
               else
               {
                  mask = 0x80;
                  *dp = (png_byte)v;
                  dp++;
                  v = 0;
               }
            }
            if (mask != 0x80)
               *dp = (png_byte)v;
            break;
         }
         case 2:
         {
            png_bytep sp, dp;
            int shift, v;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            sp = row;
            dp = row;
            shift = 6;
            v = 0;
            for (i = 0; i < row_width; i++)
            {
               png_byte value;

               value = (png_byte)(*sp & 0x03);
               v |= (value << shift);
               if (shift == 0)
               {
                  shift = 6;
                  *dp = (png_byte)v;
                  dp++;
                  v = 0;
               }
               else
                  shift -= 2;
               sp++;
            }
            if (shift != 6)
               *dp = (png_byte)v;
            break;
         }
         case 4:
         {
            png_bytep sp, dp;
            int shift, v;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            sp = row;
            dp = row;
            shift = 4;
            v = 0;
            for (i = 0; i < row_width; i++)
            {
               png_byte value;

               value = (png_byte)(*sp & 0x0f);
               v |= (value << shift);

               if (shift == 0)
               {
                  shift = 4;
                  *dp = (png_byte)v;
                  dp++;
                  v = 0;
               }
               else
                  shift -= 4;

               sp++;
            }
            if (shift != 4)
               *dp = (png_byte)v;
            break;
         }
      }
      row_info->bit_depth = (png_byte)bit_depth;
      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
      row_info->rowbytes =
         ((row_info->width * row_info->pixel_depth + 7) >> 3);
   }
}
#endif

#if defined(PNG_WRITE_SHIFT_SUPPORTED)
/* Shift pixel values to take advantage of whole range.  Pass the
 * true number of bits in bit_depth.  The row should be packed
 * according to row_info->bit_depth.  Thus, if you had a row of
 * bit depth 4, but the pixels only had values from 0 to 7, you
 * would pass 3 as bit_depth, and this routine would translate the
 * data to 0 to 15.
 */
void /* PRIVATE */
png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
{
   png_debug(1, "in png_do_shift\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL &&
#else
   if (
#endif
      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
   {
      int shift_start[4], shift_dec[4];
      int channels = 0;

      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->red;
         shift_dec[channels] = bit_depth->red;
         channels++;
         shift_start[channels] = row_info->bit_depth - bit_depth->green;
         shift_dec[channels] = bit_depth->green;
         channels++;
         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
         shift_dec[channels] = bit_depth->blue;
         channels++;
      }
      else
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
         shift_dec[channels] = bit_depth->gray;
         channels++;
      }
      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
         shift_dec[channels] = bit_depth->alpha;
         channels++;
      }

      /* with low row depths, could only be grayscale, so one channel */
      if (row_info->bit_depth < 8)
      {
         png_bytep bp = row;
         png_uint_32 i;
         png_byte mask;
         png_uint_32 row_bytes = row_info->rowbytes;

         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
            mask = 0x55;
         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
            mask = 0x11;
         else
            mask = 0xff;

         for (i = 0; i < row_bytes; i++, bp++)
         {
            png_uint_16 v;
            int j;

            v = *bp;
            *bp = 0;
            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
            {
               if (j > 0)
                  *bp |= (png_byte)((v << j) & 0xff);
               else
                  *bp |= (png_byte)((v >> (-j)) & mask);
            }
         }
      }
      else if (row_info->bit_depth == 8)
      {
         png_bytep bp = row;
         png_uint_32 i;
         png_uint_32 istop = channels * row_info->width;

         for (i = 0; i < istop; i++, bp++)
         {

            png_uint_16 v;
            int j;
            int c = (int)(i%channels);

            v = *bp;
            *bp = 0;
            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
            {
               if (j > 0)
                  *bp |= (png_byte)((v << j) & 0xff);
               else
                  *bp |= (png_byte)((v >> (-j)) & 0xff);
            }
         }
      }
      else
      {
         png_bytep bp;
         png_uint_32 i;
         png_uint_32 istop = channels * row_info->width;

         for (bp = row, i = 0; i < istop; i++)
         {
            int c = (int)(i%channels);
            png_uint_16 value, v;
            int j;

            v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
            value = 0;
            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
            {
               if (j > 0)
                  value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
               else
                  value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
            }
            *bp++ = (png_byte)(value >> 8);
            *bp++ = (png_byte)(value & 0xff);
         }
      }
   }
}
#endif

#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
void /* PRIVATE */
png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_write_swap_alpha\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
      {
         /* This converts from ARGB to RGBA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;
            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               png_byte save = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save;
            }
         }
         /* This converts from AARRGGBB to RRGGBBAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               png_byte save[2];
               save[0] = *(sp++);
               save[1] = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save[0];
               *(dp++) = save[1];
            }
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         /* This converts from AG to GA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               png_byte save = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save;
            }
         }
         /* This converts from AAGG to GGAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               png_byte save[2];
               save[0] = *(sp++);
               save[1] = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save[0];
               *(dp++) = save[1];
            }
         }
      }
   }
}
#endif

#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
void /* PRIVATE */
png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_write_invert_alpha\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
      {
         /* This inverts the alpha channel in RGBA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;
            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
         /* This inverts the alpha channel in RRGGBBAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = (png_byte)(255 - *(sp++));
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         /* This inverts the alpha channel in GA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
         /* This inverts the alpha channel in GGAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;
            png_uint_32 row_width = row_info->width;

            for (i = 0, sp = dp = row; i < row_width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = (png_byte)(255 - *(sp++));
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
      }
   }
}
#endif

#if defined(PNG_MNG_FEATURES_SUPPORTED)
/* undoes intrapixel differencing  */
void /* PRIVATE */
png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_write_intrapixel\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       (row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
      if (row_info->bit_depth == 8)
      {
         png_bytep rp;
         png_uint_32 i;

         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
            bytes_per_pixel = 3;
         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
            bytes_per_pixel = 4;
         else
            return;

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
            *(rp)   = (png_byte)((*rp     - *(rp+1))&0xff);
            *(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff);
         }
      }
      else if (row_info->bit_depth == 16)
      {
         png_bytep rp;
         png_uint_32 i;

         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
            bytes_per_pixel = 6;
         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
            bytes_per_pixel = 8;
         else
            return;

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
            png_uint_32 s0=*(rp  )<<8 | *(rp+1);
            png_uint_32 s1=*(rp+2)<<8 | *(rp+3);
            png_uint_32 s2=*(rp+4)<<8 | *(rp+5);
            png_uint_32 red=(s0-s1)&0xffff;
            png_uint_32 blue=(s2-s1)&0xffff;
            *(rp  ) = (png_byte)((red>>8)&0xff);
            *(rp+1) = (png_byte)(red&0xff);
            *(rp+4) = (png_byte)((blue>>8)&0xff);
            *(rp+5) = (png_byte)(blue&0xff);
         }
      }
   }
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */
#endif /* PNG_WRITE_SUPPORTED */

--- NEW FILE: pngrutil.c ---

/* pngrutil.c - utilities to read a PNG file
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file contains routines that are only called from within
 * libpng itself during the course of reading an image.
 */

#define PNG_INTERNAL
#include "png.h"

#if defined(_WIN32_WCE)
/* strtod() function is not supported on WindowsCE */
#  ifdef PNG_FLOATING_POINT_SUPPORTED
[...2961 lines suppressed...]
#endif

#ifdef PNG_MAX_MALLOC_64K
   if ((png_uint_32)png_ptr->rowbytes + 1 > (png_uint_32)65536L)
      png_error(png_ptr, "This image requires a row greater than 64KB");
#endif
   png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(
      png_ptr->rowbytes + 1));

   png_memset_check(png_ptr, png_ptr->prev_row, 0, png_ptr->rowbytes + 1);

   png_debug1(3, "width = %lu,\n", png_ptr->width);
   png_debug1(3, "height = %lu,\n", png_ptr->height);
   png_debug1(3, "iwidth = %lu,\n", png_ptr->iwidth);
   png_debug1(3, "num_rows = %lu\n", png_ptr->num_rows);
   png_debug1(3, "rowbytes = %lu,\n", png_ptr->rowbytes);
   png_debug1(3, "irowbytes = %lu,\n", png_ptr->irowbytes);

   png_ptr->flags |= PNG_FLAG_ROW_INIT;
}

--- NEW FILE: pngget.c ---

/* pngget.c - retrieval of values from info struct
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

#define PNG_INTERNAL
#include "png.h"

png_uint_32 PNGAPI
png_get_valid(png_structp png_ptr, png_infop info_ptr, png_uint_32 flag)
{
   if (png_ptr != NULL && info_ptr != NULL)
      return(info_ptr->valid & flag);
   else
      return(0);
}

png_uint_32 PNGAPI
png_get_rowbytes(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
      return(info_ptr->rowbytes);
   else
      return(0);
}

#if defined(PNG_INFO_IMAGE_SUPPORTED)
png_bytepp PNGAPI
png_get_rows(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
      return(info_ptr->row_pointers);
   else
      return(0);
}
#endif

#ifdef PNG_EASY_ACCESS_SUPPORTED
/* easy access to info, added in libpng-0.99 */
png_uint_32 PNGAPI
png_get_image_width(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->width;
   }
   return (0);
}

png_uint_32 PNGAPI
png_get_image_height(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->height;
   }
   return (0);
}

png_byte PNGAPI
png_get_bit_depth(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->bit_depth;
   }
   return (0);
}

png_byte PNGAPI
png_get_color_type(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->color_type;
   }
   return (0);
}

png_byte PNGAPI
png_get_filter_type(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->filter_type;
   }
   return (0);
}

png_byte PNGAPI
png_get_interlace_type(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->interlace_type;
   }
   return (0);
}

png_byte PNGAPI
png_get_compression_type(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
   {
      return info_ptr->compression_type;
   }
   return (0);
}

png_uint_32 PNGAPI
png_get_x_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_pHYs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pHYs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_x_pixels_per_meter");
      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
          return (0);
      else return (info_ptr->x_pixels_per_unit);
   }
#else
   return (0);
#endif
   return (0);
}

png_uint_32 PNGAPI
png_get_y_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_pHYs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pHYs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_y_pixels_per_meter");
      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
          return (0);
      else return (info_ptr->y_pixels_per_unit);
   }
#else
   return (0);
#endif
   return (0);
}

png_uint_32 PNGAPI
png_get_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_pHYs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pHYs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_pixels_per_meter");
      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER ||
         info_ptr->x_pixels_per_unit != info_ptr->y_pixels_per_unit)
          return (0);
      else return (info_ptr->x_pixels_per_unit);
   }
#else
   return (0);
#endif
   return (0);
}

#ifdef PNG_FLOATING_POINT_SUPPORTED
float PNGAPI
png_get_pixel_aspect_ratio(png_structp png_ptr, png_infop info_ptr)
   {
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_pHYs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pHYs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_aspect_ratio");
      if (info_ptr->x_pixels_per_unit == 0)
         return ((float)0.0);
      else
         return ((float)((float)info_ptr->y_pixels_per_unit
            /(float)info_ptr->x_pixels_per_unit));
   }
#else
   return (0.0);
#endif
   return ((float)0.0);
}
#endif

png_int_32 PNGAPI
png_get_x_offset_microns(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_oFFs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_oFFs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
          return (0);
      else return (info_ptr->x_offset);
   }
#else
   return (0);
#endif
   return (0);
}

png_int_32 PNGAPI
png_get_y_offset_microns(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_oFFs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_oFFs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
          return (0);
      else return (info_ptr->y_offset);
   }
#else
   return (0);
#endif
   return (0);
}

png_int_32 PNGAPI
png_get_x_offset_pixels(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_oFFs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_oFFs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
          return (0);
      else return (info_ptr->x_offset);
   }
#else
   return (0);
#endif
   return (0);
}

png_int_32 PNGAPI
png_get_y_offset_pixels(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
#if defined(PNG_oFFs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_oFFs)
   {
      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
          return (0);
      else return (info_ptr->y_offset);
   }
#else
   return (0);
#endif
   return (0);
}

#if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
png_uint_32 PNGAPI
png_get_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
{
   return ((png_uint_32)((float)png_get_pixels_per_meter(png_ptr, info_ptr)
     *.0254 +.5));
}

png_uint_32 PNGAPI
png_get_x_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
{
   return ((png_uint_32)((float)png_get_x_pixels_per_meter(png_ptr, info_ptr)
     *.0254 +.5));
}

png_uint_32 PNGAPI
png_get_y_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
{
   return ((png_uint_32)((float)png_get_y_pixels_per_meter(png_ptr, info_ptr)
     *.0254 +.5));
}

float PNGAPI
png_get_x_offset_inches(png_structp png_ptr, png_infop info_ptr)
{
   return ((float)png_get_x_offset_microns(png_ptr, info_ptr)
     *.00003937);
}

float PNGAPI
png_get_y_offset_inches(png_structp png_ptr, png_infop info_ptr)
{
   return ((float)png_get_y_offset_microns(png_ptr, info_ptr)
     *.00003937);
}

#if defined(PNG_pHYs_SUPPORTED)
png_uint_32 PNGAPI
png_get_pHYs_dpi(png_structp png_ptr, png_infop info_ptr,
   png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
{
   png_uint_32 retval = 0;

   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function\n", "pHYs");
      if (res_x != NULL)
      {
         *res_x = info_ptr->x_pixels_per_unit;
         retval |= PNG_INFO_pHYs;
      }
      if (res_y != NULL)
      {
         *res_y = info_ptr->y_pixels_per_unit;
         retval |= PNG_INFO_pHYs;
      }
      if (unit_type != NULL)
      {
         *unit_type = (int)info_ptr->phys_unit_type;
         retval |= PNG_INFO_pHYs;
         if(*unit_type == 1)
         {
            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
         }
      }
   }
   return (retval);
}
#endif /* PNG_pHYs_SUPPORTED */
#endif  /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */

/* png_get_channels really belongs in here, too, but it's been around longer */

#endif  /* PNG_EASY_ACCESS_SUPPORTED */

png_byte PNGAPI
png_get_channels(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
      return(info_ptr->channels);
   else
      return (0);
}

png_bytep PNGAPI
png_get_signature(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr != NULL && info_ptr != NULL)
      return(info_ptr->signature);
   else
      return (NULL);
}

#if defined(PNG_bKGD_SUPPORTED)
png_uint_32 PNGAPI
png_get_bKGD(png_structp png_ptr, png_infop info_ptr,
   png_color_16p *background)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
      && background != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "bKGD");
      *background = &(info_ptr->background);
      return (PNG_INFO_bKGD);
   }
   return (0);
}
#endif

#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_cHRM(png_structp png_ptr, png_infop info_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)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
   {
      png_debug1(1, "in %s retrieval function\n", "cHRM");
      if (white_x != NULL)
         *white_x = (double)info_ptr->x_white;
      if (white_y != NULL)
         *white_y = (double)info_ptr->y_white;
      if (red_x != NULL)
         *red_x = (double)info_ptr->x_red;
      if (red_y != NULL)
         *red_y = (double)info_ptr->y_red;
      if (green_x != NULL)
         *green_x = (double)info_ptr->x_green;
      if (green_y != NULL)
         *green_y = (double)info_ptr->y_green;
      if (blue_x != NULL)
         *blue_x = (double)info_ptr->x_blue;
      if (blue_y != NULL)
         *blue_y = (double)info_ptr->y_blue;
      return (PNG_INFO_cHRM);
   }
   return (0);
}
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
   png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
   png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
   png_fixed_point *blue_x, png_fixed_point *blue_y)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
   {
      png_debug1(1, "in %s retrieval function\n", "cHRM");
      if (white_x != NULL)
         *white_x = info_ptr->int_x_white;
      if (white_y != NULL)
         *white_y = info_ptr->int_y_white;
      if (red_x != NULL)
         *red_x = info_ptr->int_x_red;
      if (red_y != NULL)
         *red_y = info_ptr->int_y_red;
      if (green_x != NULL)
         *green_x = info_ptr->int_x_green;
      if (green_y != NULL)
         *green_y = info_ptr->int_y_green;
      if (blue_x != NULL)
         *blue_x = info_ptr->int_x_blue;
      if (blue_y != NULL)
         *blue_y = info_ptr->int_y_blue;
      return (PNG_INFO_cHRM);
   }
   return (0);
}
#endif
#endif

#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_gAMA(png_structp png_ptr, png_infop info_ptr, double *file_gamma)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
      && file_gamma != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "gAMA");
      *file_gamma = (double)info_ptr->gamma;
      return (PNG_INFO_gAMA);
   }
   return (0);
}
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_gAMA_fixed(png_structp png_ptr, png_infop info_ptr,
    png_fixed_point *int_file_gamma)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
      && int_file_gamma != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "gAMA");
      *int_file_gamma = info_ptr->int_gamma;
      return (PNG_INFO_gAMA);
   }
   return (0);
}
#endif
#endif

#if defined(PNG_sRGB_SUPPORTED)
png_uint_32 PNGAPI
png_get_sRGB(png_structp png_ptr, png_infop info_ptr, int *file_srgb_intent)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
      && file_srgb_intent != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "sRGB");
      *file_srgb_intent = (int)info_ptr->srgb_intent;
      return (PNG_INFO_sRGB);
   }
   return (0);
}
#endif

#if defined(PNG_iCCP_SUPPORTED)
png_uint_32 PNGAPI
png_get_iCCP(png_structp png_ptr, png_infop info_ptr,
             png_charpp name, int *compression_type,
             png_charpp profile, png_uint_32 *proflen)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
      && name != NULL && profile != NULL && proflen != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "iCCP");
      *name = info_ptr->iccp_name;
      *profile = info_ptr->iccp_profile;
      /* compression_type is a dummy so the API won't have to change
         if we introduce multiple compression types later. */
      *proflen = (int)info_ptr->iccp_proflen;
      *compression_type = (int)info_ptr->iccp_compression;
      return (PNG_INFO_iCCP);
   }
   return (0);
}
#endif

#if defined(PNG_sPLT_SUPPORTED)
png_uint_32 PNGAPI
png_get_sPLT(png_structp png_ptr, png_infop info_ptr,
             png_sPLT_tpp spalettes)
{
   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
     *spalettes = info_ptr->splt_palettes;
   return ((png_uint_32)info_ptr->splt_palettes_num);
}
#endif

#if defined(PNG_hIST_SUPPORTED)
png_uint_32 PNGAPI
png_get_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p *hist)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
      && hist != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "hIST");
      *hist = info_ptr->hist;
      return (PNG_INFO_hIST);
   }
   return (0);
}
#endif

png_uint_32 PNGAPI
png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
   png_uint_32 *width, png_uint_32 *height, int *bit_depth,
   int *color_type, int *interlace_type, int *compression_type,
   int *filter_type)

{
   if (png_ptr != NULL && info_ptr != NULL && width != NULL && height != NULL &&
      bit_depth != NULL && color_type != NULL)
   {
      int pixel_depth, channels;
      png_uint_32 rowbytes_per_pixel;

      png_debug1(1, "in %s retrieval function\n", "IHDR");
      *width = info_ptr->width;
      *height = info_ptr->height;
      *bit_depth = info_ptr->bit_depth;
      *color_type = info_ptr->color_type;
      if (compression_type != NULL)
         *compression_type = info_ptr->compression_type;
      if (filter_type != NULL)
         *filter_type = info_ptr->filter_type;
      if (interlace_type != NULL)
         *interlace_type = info_ptr->interlace_type;

      /* check for potential overflow of rowbytes */
      if (*color_type == PNG_COLOR_TYPE_PALETTE)
         channels = 1;
      else if (*color_type & PNG_COLOR_MASK_COLOR)
         channels = 3;
      else
         channels = 1;
      if (*color_type & PNG_COLOR_MASK_ALPHA)
         channels++;
      pixel_depth = *bit_depth * channels;
      rowbytes_per_pixel = (pixel_depth + 7) >> 3;
      if ((*width > PNG_MAX_UINT/rowbytes_per_pixel))
      {
         png_warning(png_ptr,
            "Width too large for libpng to process image data.");
      }
      return (1);
   }
   return (0);
}

#if defined(PNG_oFFs_SUPPORTED)
png_uint_32 PNGAPI
png_get_oFFs(png_structp png_ptr, png_infop info_ptr,
   png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
      && offset_x != NULL && offset_y != NULL && unit_type != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "oFFs");
      *offset_x = info_ptr->x_offset;
      *offset_y = info_ptr->y_offset;
      *unit_type = (int)info_ptr->offset_unit_type;
      return (PNG_INFO_oFFs);
   }
   return (0);
}
#endif

#if defined(PNG_pCAL_SUPPORTED)
png_uint_32 PNGAPI
png_get_pCAL(png_structp png_ptr, png_infop info_ptr,
   png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
   png_charp *units, png_charpp *params)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
      && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
      nparams != NULL && units != NULL && params != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "pCAL");
      *purpose = info_ptr->pcal_purpose;
      *X0 = info_ptr->pcal_X0;
      *X1 = info_ptr->pcal_X1;
      *type = (int)info_ptr->pcal_type;
      *nparams = (int)info_ptr->pcal_nparams;
      *units = info_ptr->pcal_units;
      *params = info_ptr->pcal_params;
      return (PNG_INFO_pCAL);
   }
   return (0);
}
#endif

#if defined(PNG_sCAL_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_sCAL(png_structp png_ptr, png_infop info_ptr,
             int *unit, double *width, double *height)
{
    if (png_ptr != NULL && info_ptr != NULL &&
       (info_ptr->valid & PNG_INFO_sCAL))
    {
        *unit = info_ptr->scal_unit;
        *width = info_ptr->scal_pixel_width;
        *height = info_ptr->scal_pixel_height;
        return (PNG_INFO_sCAL);
    }
    return(0);
}
#else
#ifdef PNG_FIXED_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_sCAL_s(png_structp png_ptr, png_infop info_ptr,
             int *unit, png_charpp width, png_charpp height)
{
    if (png_ptr != NULL && info_ptr != NULL &&
       (info_ptr->valid & PNG_INFO_sCAL))
    {
        *unit = info_ptr->scal_unit;
        *width = info_ptr->scal_s_width;
        *height = info_ptr->scal_s_height;
        return (PNG_INFO_sCAL);
    }
    return(0);
}
#endif
#endif
#endif

#if defined(PNG_pHYs_SUPPORTED)
png_uint_32 PNGAPI
png_get_pHYs(png_structp png_ptr, png_infop info_ptr,
   png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
{
   png_uint_32 retval = 0;

   if (png_ptr != NULL && info_ptr != NULL &&
      (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function\n", "pHYs");
      if (res_x != NULL)
      {
         *res_x = info_ptr->x_pixels_per_unit;
         retval |= PNG_INFO_pHYs;
      }
      if (res_y != NULL)
      {
         *res_y = info_ptr->y_pixels_per_unit;
         retval |= PNG_INFO_pHYs;
      }
      if (unit_type != NULL)
      {
         *unit_type = (int)info_ptr->phys_unit_type;
         retval |= PNG_INFO_pHYs;
      }
   }
   return (retval);
}
#endif

png_uint_32 PNGAPI
png_get_PLTE(png_structp png_ptr, png_infop info_ptr, png_colorp *palette,
   int *num_palette)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
       && palette != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "PLTE");
      *palette = info_ptr->palette;
      *num_palette = info_ptr->num_palette;
      png_debug1(3, "num_palette = %d\n", *num_palette);
      return (PNG_INFO_PLTE);
   }
   return (0);
}

#if defined(PNG_sBIT_SUPPORTED)
png_uint_32 PNGAPI
png_get_sBIT(png_structp png_ptr, png_infop info_ptr, png_color_8p *sig_bit)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
      && sig_bit != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "sBIT");
      *sig_bit = &(info_ptr->sig_bit);
      return (PNG_INFO_sBIT);
   }
   return (0);
}
#endif

#if defined(PNG_TEXT_SUPPORTED)
png_uint_32 PNGAPI
png_get_text(png_structp png_ptr, png_infop info_ptr, png_textp *text_ptr,
   int *num_text)
{
   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
   {
      png_debug1(1, "in %s retrieval function\n",
         (png_ptr->chunk_name[0] == '\0' ? "text"
             : (png_const_charp)png_ptr->chunk_name));
      if (text_ptr != NULL)
         *text_ptr = info_ptr->text;
      if (num_text != NULL)
         *num_text = info_ptr->num_text;
      return ((png_uint_32)info_ptr->num_text);
   }
   if (num_text != NULL)
     *num_text = 0;
   return(0);
}
#endif

#if defined(PNG_tIME_SUPPORTED)
png_uint_32 PNGAPI
png_get_tIME(png_structp png_ptr, png_infop info_ptr, png_timep *mod_time)
{
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
       && mod_time != NULL)
   {
      png_debug1(1, "in %s retrieval function\n", "tIME");
      *mod_time = &(info_ptr->mod_time);
      return (PNG_INFO_tIME);
   }
   return (0);
}
#endif

#if defined(PNG_tRNS_SUPPORTED)
png_uint_32 PNGAPI
png_get_tRNS(png_structp png_ptr, png_infop info_ptr,
   png_bytep *trans, int *num_trans, png_color_16p *trans_values)
{
   png_uint_32 retval = 0;
   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
   {
      png_debug1(1, "in %s retrieval function\n", "tRNS");
      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
          if (trans != NULL)
          {
             *trans = info_ptr->trans;
             retval |= PNG_INFO_tRNS;
          }
          if (trans_values != NULL)
             *trans_values = &(info_ptr->trans_values);
      }
      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
      {
          if (trans_values != NULL)
          {
             *trans_values = &(info_ptr->trans_values);
             retval |= PNG_INFO_tRNS;
          }
          if(trans != NULL)
             *trans = NULL;
      }
      if(num_trans != NULL)
      {
         *num_trans = info_ptr->num_trans;
         retval |= PNG_INFO_tRNS;
      }
   }
   return (retval);
}
#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
png_uint_32 PNGAPI
png_get_unknown_chunks(png_structp png_ptr, png_infop info_ptr,
             png_unknown_chunkpp unknowns)
{
   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
     *unknowns = info_ptr->unknown_chunks;
   return ((png_uint_32)info_ptr->unknown_chunks_num);
}
#endif

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
png_byte PNGAPI
png_get_rgb_to_gray_status (png_structp png_ptr)
{
   return (png_byte)(png_ptr? png_ptr->rgb_to_gray_status : 0);
}
#endif

#if defined(PNG_USER_CHUNKS_SUPPORTED)
png_voidp PNGAPI
png_get_user_chunk_ptr(png_structp png_ptr)
{
   return (png_ptr? png_ptr->user_chunk_ptr : NULL);
}
#endif


png_uint_32 PNGAPI
png_get_compression_buffer_size(png_structp png_ptr)
{
   return (png_uint_32)(png_ptr? png_ptr->zbuf_size : 0L);
}



--- NEW FILE: CHANGES ---
CHANGES - changes for libpng

version 0.2
  added reader into png.h
  fixed small problems in stub file
version 0.3
  added pull reader
  split up pngwrite.c to several files
  added pnglib.txt
  added example.c
  cleaned up writer, adding a few new tranformations
  fixed some bugs in writer
  interfaced with zlib 0.5
  added K&R support
  added check for 64 KB blocks for 16 bit machines
version 0.4
  cleaned up code and commented code
  simplified time handling into png_time
  created png_color_16 and png_color_8 to handle color needs
  cleaned up color type defines
  fixed various bugs
  made various names more consistant
  interfaced with zlib 0.71
  cleaned up zTXt reader and writer (using zlib's Reset functions)
  split transformations into pngrtran.c and pngwtran.c
version 0.5
  interfaced with zlib 0.8
  fixed many reading and writing bugs
  saved using 3 spaces instead of tabs
version 0.6
  added png_large_malloc() and png_large_free()
  added png_size_t
  cleaned up some compiler warnings
  added png_start_read_image()
version 0.7
  cleaned up lots of bugs
  finished dithering and other stuff
  added test program
  changed name from pnglib to libpng
version 0.71 [June, 1995]
  changed pngtest.png for zlib 0.93
  fixed error in libpng.txt and example.c
version 0.8
  cleaned up some bugs
  added png_set_filler()
  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
  added #define's to remove unwanted code
  moved png_info_init() to png.c
  added old_size into png_realloc()
  added functions to manually set filtering and compression info
  changed compression parameters based on image type
  optimized filter selection code
  added version info
  changed external functions passing floats to doubles (k&r problems?)
  put all the configurable stuff in pngconf.h
  enabled png_set_shift to work with paletted images on read
  added png_read_update_info() - updates info structure with
     transformations
version 0.81 [August, 1995]
  incorporated Tim Wegner's medium model code (thanks, Tim)
version 0.82 [September, 1995]
  [unspecified changes]
version 0.85 [December, 1995]
  added more medium model code (almost everything's a far)
  added i/o, error, and memory callback functions
  fixed some bugs (16 bit, 4 bit interlaced, etc.)
  added first run progressive reader (barely tested)
version 0.86 [January, 1996]
  fixed bugs
  improved documentation
version 0.87 [January, 1996]
  fixed medium model bugs
  fixed other bugs introduced in 0.85 and 0.86
  added some minor documentation
version 0.88 [January, 1996]
  fixed progressive bugs
  replaced tabs with spaces
  cleaned up documentation
  added callbacks for read/write and warning/error functions
version 0.89 [July, 1996]
  added new initialization API to make libpng work better with shared libs
     we now have png_create_read_struct(), png_create_write_struct(),
     png_create_info_struct(), png_destroy_read_struct(), and
     png_destroy_write_struct() instead of the separate calls to
     malloc and png_read_init(), png_info_init(), and png_write_init()
  changed warning/error callback functions to fix bug - this means you
     should use the new initialization API if you were using the old
     png_set_message_fn() calls, and that the old API no longer exists
     so that people are aware that they need to change their code
  changed filter selection API to allow selection of multiple filters
     since it didn't work in previous versions of libpng anyways
  optimized filter selection code
  fixed png_set_background() to allow using an arbitrary RGB color for
     paletted images
  fixed gamma and background correction for paletted images, so
     png_correct_palette is not needed unless you are correcting an
     external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
     in pngconf.h) - if nobody uses this, it may disappear in the future.
  fixed bug with Borland 64K memory allocation (Alexander Lehmann)
  fixed bug in interlace handling (Smarasderagd, I think)
  added more error checking for writing and image to reduce invalid files
  separated read and write functions so that they won't both be linked
     into a binary when only reading or writing functionality is used
  new pngtest image also has interlacing and zTXt
  updated documentation to reflect new API
version 0.90 [January, 1997]
  made CRC errors/warnings on critical and ancillary chunks configurable
  libpng will use the zlib CRC routines by (compile-time) default
  changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
  added external C++ wrapper statements to png.h (Gilles Dauphin)
  allow PNG file to be read when some or all of file signature has already
     been read from the beginning of the stream.  ****This affects the size
     of info_struct and invalidates all programs that use a shared libpng****
  fixed png_filler() declarations
  fixed? background color conversions
  fixed order of error function pointers to match documentation
  current chunk name is now available in png_struct to reduce the number
     of nearly identical error messages (will simplify multi-lingual
     support when available)
  try to get ready for unknown-chunk callback functions:
     - previously read critical chunks are flagged, so the chunk handling
       routines can determine if the chunk is in the right place
     - all chunk handling routines have the same prototypes, so we will
       be able to handle all chunks via a callback mechanism
  try to fix Linux "setjmp" buffer size problems
  removed png_large_malloc, png_large_free, and png_realloc functions.
version 0.95 [March, 1997]
  fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
  fixed bug in PNG file signature compares when start != 0
  changed parameter type of png_set_filler(...filler...) from png_byte
     to png_uint_32
  added test for MACOS to ensure that both math.h and fp.h are not #included
  added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
  added "packswap" transformation, which changes the endianness of
     packed-pixel bytes (Kevin Bracey)
  added "strip_alpha" transformation, which removes the alpha channel of
     input images without using it (not neccesarily a good idea)
  added "swap_alpha" transformation, which puts the alpha channel in front
     of the color bytes instead of after
  removed all implicit variable tests which assume NULL == 0 (I think)
  changed several variables to "png_size_t" to show 16/32-bit limitations
  added new pCAL chunk read/write support
  added experimental filter selection weighting (Greg Roelofs)
  removed old png_set_rgbx() and png_set_xrgb() functions that have been
     obsolete for about 2 years now (use png_set_filler() instead)
  added macros to read 16- and 32-bit ints directly from buffer, to be
     used only on those systems that support it (namely PowerPC and 680x0)
     With some testing, this may become the default for MACOS/PPC systems.
  only calculate CRC on data if we are going to use it
  added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
  added macros for simple libpng debugging output selectable at compile time
  removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
  more description of info_struct in libpng.txt and png.h
  more instructions in example.c
  more chunk types tested in pngtest.c
  renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
     png_set_<chunk>.  We now have corresponding png_get_<chunk>
     functions in pngget.c to get infomation in info_ptr.  This isolates
     the application from the internal organization of png_info_struct
     (good for shared library implementations).
version 0.96 [May, 1997]
  fixed serious bug with < 8bpp images introduced in 0.95
  fixed 256-color transparency bug (Greg Roelofs)
  fixed up documentation (Greg Roelofs, Laszlo Nyul)
  fixed "error" in pngconf.h for Linux setjmp() behaviour
  fixed DOS medium model support (Tim Wegner)
  fixed png_check_keyword() for case with error in static string text
  added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
  added typecasts to quiet compiler errors
  added more debugging info
version 0.97 [January, 1998]
  removed PNG_USE_OWN_CRC capability
  relocated png_set_crc_action from pngrutil.c to pngrtran.c
  fixed typecasts of "new_key", etc. (Andreas Dilger)
  added RFC 1152 [sic] date support
  fixed bug in gamma handling of 4-bit grayscale
  added 2-bit grayscale gamma handling (Glenn R-P)
  added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
  minor corrections in libpng.txt
  added simple sRGB support (Glenn R-P)
  easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
     all configurable options can be selected from command-line instead
     of having to edit pngconf.h (Glenn R-P)
  fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
  added more conditions for png_do_background, to avoid changing
     black pixels to background when a background is supplied and
     no pixels are transparent
  repaired PNG_NO_STDIO behaviour
  tested NODIV support and made it default behaviour (Greg Roelofs)
  added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
  regularized version numbering scheme and bumped shared-library major
     version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
version 0.98 [January, 1998]
  cleaned up some typos in libpng.txt and in code documentation
  fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
  cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
  changed recommendation about file_gamma for PC images to .51 from .45,
     in example.c and libpng.txt, added comments to distinguish between
     screen_gamma, viewing_gamma, and display_gamma.
  changed all references to RFC1152 to read RFC1123 and changed the
     PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
  added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
  changed srgb_intent from png_byte to int to avoid compiler bugs
version 0.99 [January 30, 1998]
  free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
  fixed a longstanding "packswap" bug in pngtrans.c
  fixed some inconsistencies in pngconf.h that prevented compiling with
     PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
  fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
  changed recommendation about file_gamma for PC images to .50 from .51 in
     example.c and libpng.txt, and changed file_gamma for sRGB images to .45
  added a number of functions to access information from the png structure
     png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
  added TARGET_MACOS similar to zlib-1.0.8
  define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
  added type casting to all png_malloc() function calls
version 0.99a [January 31, 1998]
  Added type casts and parentheses to all returns that return a value.(Tim W.)
version 0.99b [February 4, 1998]
  Added type cast png_uint_32 on malloc function calls where needed.
  Changed type of num_hist from png_uint_32 to int (same as num_palette).
  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
  Renamed makefile.elf to makefile.lnx.
version 0.99c [February 7, 1998]
  More type casting.  Removed erroneous overflow test in pngmem.c.
  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
version 0.99d [February 11, 1998]
  Renamed "far_to_near()" "png_far_to_near()"
  Revised libpng.3
  Version 99c "buffered" operations didn't work as intended.  Replaced them
    with png_memcpy_check() and png_memset_check().
  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
    unused png_ptr, mostly in pngget.c and pngset.c.
  Check for overlength tRNS chunk present when indexed-color PLTE is read.
  Cleaned up spelling errors in libpng.3/libpng.txt
  Corrected a problem with png_get_tRNS() which returned undefined trans array
version 0.99e [February 28, 1998]
  Corrected png_get_tRNS() again.
  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
  Touched up example.c to make more of it compileable, although the entire
    file still can't be compiled (Willem van Schaik)
  Fixed a bug in png_do_shift() (Bryan Tsai)
  Added a space in png.h prototype for png_write_chunk_start()
  Replaced pngtest.png with one created with zlib 1.1.1
  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
version 0.99f [March 5, 1998]
  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
  Added pointers to "note on libpng versions" in makefile.lnx and README
  Added row callback feature when reading and writing nonprogressive rows
     and added a test of this feature in pngtest.c
  Added user transform callbacks, with test of the feature in pngtest.c
version 0.99g [March 6, 1998, morning]
  Minor changes to pngtest.c to suppress compiler warnings.
  Removed "beta" language from documentation.
version 0.99h [March 6, 1998, evening]
  Minor changes to previous minor changes to pngtest.c
  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
  and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
  Added user transform capability
version 1.00 [March 7, 1998]
  Changed several typedefs in pngrutil.c
  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
  replaced "while(1)" with "for(;;)"
  added PNGARG() to prototypes in pngtest.c and removed some prototypes
  updated some of the makefiles (Tom Lane)
  changed some typedefs (s_start, etc.) in pngrutil.c
  fixed dimensions of "short_months" array in pngwrite.c
  Replaced ansi2knr.c with the one from jpeg-v6
version 1.0.0 [March 8, 1998]
  Changed name from 1.00 to 1.0.0 (Adam Costello)
  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
version 1.0.0a [March 9, 1998]
  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
  (Greg Roelofs)
  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
  for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
  Tom Lane)
  Make months range from 1-12 in png_convert_to_rfc1123
version 1.0.0b [March 13, 1998]
  Quieted compiler complaints about two empty "for" loops in pngrutil.c
  Minor changes to makefile.s2x
  Removed #ifdef/#endif around a png_free() in pngread.c
version 1.0.1 [March 14, 1998]
  Changed makefile.s2x to reduce security risk of using a relative pathname
  Fixed some typos in the documentation (Greg).
  Fixed a problem with value of "channels" returned by png_read_update_info()
version 1.0.1a [April 21, 1998]
  Optimized Paeth calculations by replacing abs() function calls with intrinsics
  plus other loop optimizations. Improves avg decoding speed by about 20%.
  Commented out i386istic "align" compiler flags in makefile.lnx.
  Reduced the default warning level in some makefiles, to make them consistent.
  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
  Added grayscale and 16-bit capability to png_do_read_filler().
  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
    too large when writing an image with bit_depth < 8 (Bob Dellaca).
  Corrected some bugs in the experimental weighted filtering heuristics.
  Moved a misplaced pngrutil code block that truncates tRNS if it has more
    than num_palette entries -- test was done before num_palette was defined.
  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
  Changed compiler flags in makefile.wat for better optimization (Pawel Mrochen).
version 1.0.1b [May 2, 1998]
  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
  Added makefile.sco (contributed by Mike Hopkirk).
  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
  More work on the Paeth-filtering, achieving imperceptible speedup (A Kleinert).
  More work on loop optimization which may help when compiled with C++ compilers.
  Added warnings when people try to use transforms they've defined out.
  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
version 1.0.1c [May 11, 1998]
  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
    filler bytes should have been 0xff instead of 0xf.
  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
    for consistency, in pngconf.h
  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
    to remove unwanted capabilities via the compile line
  Made some corrections to grammar (which, it's) in documentation (Greg).
  Corrected example.c, use of row_pointers in png_write_image().
version 1.0.1d [May 24, 1998]
  Corrected several statements that used side effects illegally in pngrutil.c
    and pngtrans.c, that were introduced in version 1.0.1b
  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
  More corrections to example.c, use of row_pointers in png_write_image()
    and png_read_rows().
  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
  Changed several loops from count-down to count-up, for consistency.
version 1.0.1e [June 6, 1998]
  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
    added warnings when people try to set png_read_fn and png_write_fn in
    the same structure.
  Added a test such that png_do_gamma will be done when num_trans==0
    for truecolor images that have defined a background.  This corrects an
    error that was introduced in libpng-0.90 that can cause gamma processing
    to be skipped.
  Added tests in png.h to include "trans" and "trans_values" in structures
    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
  Added capability for user-provided malloc_fn() and free_fn() functions,
    and revised pngtest.c to demonstrate their use, replacing the
    PNGTEST_DEBUG_MEM feature.
  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
version 1.0.2 [June 14, 1998]
  Fixed two bugs in makefile.bor .
version 1.0.2a [December 30, 1998]
  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
    the left-most pixel of each row (Kevin Bracey).
  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
    in pngtest.c (Duncan Simpson).
  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
    even when no tIME chunk was present in the source file.
  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
  Fixed a problem in png_read_push_finish_row(), which would not skip some
    passes that it should skip, for images that are less than 3 pixels high.
  Interchanged the order of calls to png_do_swap() and png_do_shift()
    in pngwtran.c (John Cromer).
  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
  Fixed a documentation error about default filtering with 8-bit indexed-color.
  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
    (L. Peter Deutsch).
  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
  Added png_get_copyright() and png_get_header_version() functions.
  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
  Added information about debugging in libpng.txt and libpng.3 .
  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and makefile.sco.
  Removed lines after Dynamic Dependencies" in makefile.aco .
  Revised makefile.dec to make a shared library (Jeremie Petit).
  Removed trailing blanks from all files.
version 1.0.2a [January 6, 1999]
  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
    which is obsolete.
version 1.0.3 [January 14, 1999]
  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
version 1.0.3a [August 12, 1999]
  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
     if an attempt is made to read an interlaced image when it's not supported.
  Added check if png_ptr->trans is defined before freeing it in pngread.c
  Modified the Y2K statement to include versions back to version 0.71
  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
  Replaced leading blanks with tab characters in makefile.hux
  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
  Changed (float)red and (float)green to (double)red, (double)green
     in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
  Updated documentation to refer to the PNG-1.2 specification.
  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
  Fixed bugs in calculation of the length of rowbytes when adding alpha
    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
  Added function png_set_user_transform_info() to store user_transform_ptr,
    user_depth, and user_channels into the png_struct, and a function
    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
  Added function png_set_empty_plte_permitted() to make libpng useable
    in MNG applications.
  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
    consistent with PNG-1.2, and allow variance of 500 before complaining.
  Added assembler code contributed by Intel in file pngvcrd.c and modified
    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation, Gilles Vollant)
  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
  Added some aliases for png_set_expand() in pngrtran.c, namely
    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
    (Greg Roelofs, in "PNG: The Definitive Guide").
  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
version 1.0.3b [August 26, 1999]
  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
  Changed leading blanks to tabs in all makefiles.
  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
  Made alternate versions of  png_set_expand() in pngrtran.c, namely
    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
  Revised calculation of num_blocks in pngmem.c to avoid a potentially
    negative shift distance, whose results are undefined in the C language.
  Added a check in pngset.c to prevent writing multiple tIME chunks.
  Added a check in pngwrite.c to detect invalid small window_bits sizes.
version 1.0.3d [September 4, 1999]
  Fixed type casting of igamma in pngrutil.c
  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
version 1.0.4 [September 24, 1999]
  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
  Made several minor corrections to pngtest.c
  Renamed the makefiles with longer but more user friendly extensions.
  Copied the PNG copyright and license to a separate LICENSE file.
  Revised documentation, png.h, and example.c to remove reference to
    "viewing_gamma" which no longer appears in the PNG specification.
  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
    assembler code) and makefile.vcwin32 (doesn't).
  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
  Added a copy of pngnow.png to the distribution.
version 1.0.4a [September 25, 1999]
  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
  Changed several division operations to right-shifts in pngvcrd.c
version 1.0.4b [September 30, 1999]
  Added parentheses in line 3732 of pngvcrd.c
  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
version 1.0.4c [October 1, 1999]
  Added a "png_check_version" function in png.c and pngtest.c that will generate
    a helpful compiler error if an old png.h is found in the search path.
  Changed type of png_user_transform_depth|channels from int to png_byte.
version 1.0.4d [October 6, 1999]
  Changed 0.45 to 0.45455 in png_set_sRGB()
  Removed unused PLTE entries from pngnow.png
  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
version 1.0.4e [October 10, 1999]
  Fixed sign error in pngvcrd.c (Greg Roelofs)
  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
version 1.0.4f [October 15, 1999]
  Surrounded example.c code with #if 0 .. #endif to prevent people from
    inadvertently trying to compile it.
  Changed png_get_header_version() from a function to a macro in png.h
  Added type casting mostly in pngrtran.c and pngwtran.c
  Removed some pointless "ptr = NULL" in pngmem.c
  Added a "contrib" directory containing the source code from Greg's book.
version 1.0.5 [October 15, 1999]
  Minor editing of the INSTALL and README files.
version 1.0.5a [October 23, 1999]
  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
  Further optimization and bugfix of pngvcrd.c
  Revised pngset.c so that it does not allocate or free memory in the user's
    text_ptr structure.  Instead, it makes its own copy.
  Created separate write_end_info_struct in pngtest.c for a more severe test.
  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
version 1.0.5b [November 23, 1999]
  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
    PNG_FLAG_WROTE_tIME from flags to mode.
  Added png_write_info_before_PLTE() function.
  Fixed some typecasting in contrib/gregbook/*.c
  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
    and contrib/pngminus (Martin Zinser)
version 1.0.5c [November 26, 1999]
  Moved png_get_header_version from png.h to png.c, to accomodate ansi2knr.
  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
    accomodate making DLL's: Moved usr_png_ver from global variable to function
    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
    png_CHNK and png_pass arrays to be "const".  Made the global arrays
    available to applications (although none are used in libpng itself) when
    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
  Removed some extraneous "-I" from contrib/pngminus/makefile.std
  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
version 1.0.5d [November 29, 1999]
  Add type cast (png_const_charp) two places in png.c
  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
    to applications a macro "PNG_USE_LOCAL_ARRAYS".
  #ifdef out all the new declarations when PNG_USE_GLOBAL_ARRAYS is defined.
  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
version 1.0.5e [November 30, 1999]
  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
    structure; refactored the inflate/deflate support to make adding new chunks
    with trailing compressed parts easier in the future, and added new functions
    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
  NOTE: Applications that write text chunks MUST define png_text->lang
    before calling png_set_text(). It must be set to NULL if you want to
    write tEXt or zTXt chunks.  If you want your application to be able to
    run with older versions of libpng, use

      #ifdef PNG_iTXt_SUPPORTED
         png_text[i].lang = NULL;
      #endif

  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
    offsets (Eric S. Raymond).
  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
    macros, leaving the separate macros also available.
  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
version 1.0.5f [December 6, 1999]
  Changed makefile.solaris to issue a warning about potential problems when
    the ucb "ld" is in the path ahead of the ccs "ld".
  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
  Added sCAL chunk support (Eric S. Raymond).
version 1.0.5g [December 7, 1999]
  Fixed "png_free_spallettes" typo in png.h
  Added code to handle new chunks in pngpread.c
  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
  Added "translated_key" to png_text structure and png_write_iTXt().
  Added code in pngwrite.c to work around a newly discovered zlib bug.
version 1.0.5h [December 10, 1999]
  NOTE: regarding the note for version 1.0.5e, the following must also
    be included in your code:
        png_text[i].translated_key = NULL;
  Unknown chunk handling is now supported.
  Option to eliminate all floating point support was added.  Some new
    fixed-point functions such as png_set_gAMA_fixed() were added.
  Expanded tabs and removed trailing blanks in source files.
version 1.0.5i [December 13, 1999]
  Added some type casts to silence compiler warnings.
  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
  Removed leading blanks from a #define in pngvcrd.c
  Added some parameters to the new png_set_keep_unknown_chunks() function.
  Added a test for up->location != 0 in the first instance of writing
    unknown chunks in pngwrite.c
  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
    prevent recursion.
  Added png_free_hIST() function.
  Various patches to fix bugs in the sCAL and integer cHRM processing,
    and to add some convenience macros for use with sCAL.
version 1.0.5j [December 21, 1999]
  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
    around buggy compilers.
  Added new type "png_fixed_point" for integers that hold float*100000 values
  Restored backward compatibility of tEXt/zTXt chunk processing:
    Restored the first four members of png_text to the same order as v.1.0.5d.
    Added members "lang_key" and "itxt_length" to png_text struct.  Set
    text_length=0 when "text" contains iTXt data.  Use the "compression"
    member to distinguish among tEXt/zTXt/iTXt types.  Added
    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
    longer applies.
  Fixed png_read|write_iTXt() to read|write parameters in the right order,
    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
  Reversed the order of trying to write floating-point and fixed-point gAMA.
version 1.0.5k [December 27, 1999]
  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
  Added png_handle_as_unknown() function (Glenn)
  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
    of png_ptr.
  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
version 1.0.5l [January 1, 2000]
  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
    for setting a callback function to handle unknown chunks and for
    retrieving the associated user pointer (Glenn).
version 1.0.5m [January 7, 2000]
  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
version 1.0.5n [January 9, 2000]
  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
    own memory for info_ptr->palette.  This makes it safe for the calling
    application to free its copy of the palette any time after it calls
    png_set_PLTE().
version 1.0.5o [January 20, 2000]
  Cosmetic changes only (removed some trailing blanks and TABs)
version 1.0.5p [January 31, 2000]
  Renamed pngdll.mak to makefile.bd32
  Cosmetic changes in pngtest.c
version 1.0.5q [February 5, 2000]
  Relocated the makefile.solaris warning about PATH problems.
  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
  Revised makefile.gcmmx
  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
version 1.0.5r [February 7, 2000]
  Removed superfluous prototype for png_get_itxt from png.h
  Fixed a bug in pngrtran.c that improperly expanded the background color.
  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
    of png_get_text() in libpng.txt/libpng.3.
version 1.0.5s [February 18, 2000]
  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
    new error handler that's planned for the next libpng release, and changed
    example.c, pngtest.c, and contrib programs to use this macro.
  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
  Fixed a bug in png_read_png() that caused it to fail to expand some images
    that it should have expanded.
  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
    in pngget.c
  Changed the allocation of palette, history, and trans arrays back to
    the version 1.0.5 method (linking instead of copying) which restores
    backward compatibility with version 1.0.5.  Added some remarks about
    that in example.c.  Added "free_me" member to info_ptr and png_ptr
    and added png_free_data() function.
  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
  Made cosmetic changes to pngasmrd.h
  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
  Modified png_read_png() to allocate info_ptr->row_pointers only if it
    hasn't already been allocated.
version 1.0.5t [March 4, 2000]
  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
    a 24-bit visual if one is available, and to allow abbreviated options.
  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
version 1.0.5u [March 5, 2000]
  Simplified the code that detects old png.h in png.c and pngtest.c
  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
    added png_set_rgb_to_gray_fixed() function.
  Added makefile.bc32 (32-bit Borland C++, C mode)
version 1.0.5v [March 11, 2000]
  Added some parentheses to the png_jmpbuf macro definition.
  Updated references to the zlib home page, which has moved to freesoftware.com.
  Corrected bugs in documentation regarding png_read_row() and png_write_row().
  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
version 1.0.6 [March 20, 2000]
  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
  Added makefile.sggcc (SGI IRIX with gcc)
version 1.0.6d [April 7, 2000]
  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
  Added data_length parameter to png_decompress_chunk() function
  Revised documentation to remove reference to abandoned png_free_chnk functions
  Fixed an error in png_rgb_to_gray_fixed()
  Revised example.c, usage of png_destroy_write_struct().
  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
version 1.0.6e [April 9, 2000]
  Added png_data_freer() function.
  In the code that checks for over-length tRNS chunks, added check of
    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
  Minor revisions of libpng.txt/libpng.3.
  Check for existing data and free it if the free_me flag is set, in png_set_*()
    and png_handle_*().
  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
    is defined.
  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
version 1.0.6f [April 14, 2000]
  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
  Add checks in png_set_text() for NULL members of the input text structure.
  Revised libpng.txt/libpng.3.
  Removed superfluous prototype for png_set_itxt from png.h
  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
  Changed several png_errors about malformed ancillary chunks to png_warnings.
version 1.0.6g [April 24, 2000]
  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
    and other revisions (Matthias Benckmann)
  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
    png_ptr members to restore binary compatibility with libpng-1.0.5
    (breaks compatibility with libpng-1.0.6).
version 1.0.6h [April 24, 2000]
  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
    This is a temporary change for test purposes.
version 1.0.6i [May 2, 2000]
  Rearranged some members at the end of png_info and png_struct, to put
    unknown_chunks_num and free_me within the original size of the png_structs
    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
    because some old applications allocate the structs directly instead of
    using png_create_*().
  Added documentation of user memory functions in libpng.txt/libpng.3
  Modified png_read_png so that it will use user_allocated row_pointers
    if present, unless free_me directs that it be freed, and added description
    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
    1.00) members of png_struct and png_info, to regain binary compatibility
    when you define this macro.  Capabilities lost in this event
    are user transforms (new in version 1.0.0),the user transform pointer
    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
    the high-level interface, and unknown chunks support (all new in 1.0.6).
    This was necessary because of old applications that allocate the structs
    directly as authors were instructed to do in libpng-0.88 and earlier,
    instead of using png_create_*().
  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
    can be used to detect codes that directly allocate the structs, and
    code to check these modes in png_read_init() and png_write_init() and
    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
    was not defined.
  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
version 1.0.6j [May 3, 2000]
  Overloaded png_read_init() and png_write_init() with macros that convert
    calls to png_read_init_2() or png_write_init_2() that check the version
    and structure sizes.
version 1.0.7beta11 [May 7, 2000]
  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
    which are no longer used.
  Eliminated the three new members of png_text when PNG_NO_iTXt_SUPPORTED
    or PNG_LEGACY_SUPPORTED is defined.
  Made PNG_NO_ITXT_SUPPORTED the default setting, to avoid memory overrun
    when old applications fill the info_ptr->text structure directly.
  Added PNGAPI macro, and added it to the definitions of all exported functions.
  Relocated version macro definitions ahead of the includes of zlib.h and
    pngconf.h in png.h.
version 1.0.7beta12 [May 12, 2000]
  Revised pngset.c to avoid a problem with expanding the png_debug macro.
  Deleted some extraneous defines from pngconf.h
  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
  Added png_access_version_number() function.
  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
  Expanded libpng.3/libpng.txt information about png_data_freer().
version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
    warnings instead of errors, as pngrutil.c does.
  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
    will actually write IDATs.
  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
  Make png_free_data() ignore its final parameter except when freeing data
    that can have multiple instances (text, sPLT, unknowns).
  Fixed a new bug in png_set_rows().
  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
  Added png_set_invalid() function.
  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
version 1.0.7beta15 [May 30, 2000]
  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
    fewer error messages.
  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
    and pngwutil.c.
  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
    in libpng.txt/libpng.3 the need for applications to check this.
  Changed names of png_default_*() functions in pngtest to pngtest_*().
  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
  Set each pointer to NULL after freeing it in png_free_data().
  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
    macro that conflicts with libpng's png_color_16.index. (Dimitri Papadapoulos)
  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
version 1.0.7beta16 [June 4, 2000]
  Revised the workaround of AIX string.h "index" bug.
  Added a check for overlength PLTE chunk in pngrutil.c.
  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
    when it tries to read an erroneous PhotoShop iCCP chunk.
  Added PNG_USE_DLL macro.
  Revised the copyright/disclaimer/license notice.
  Added contrib/msvctest directory
version 1.0.7rc1 [June 9, 2000]
  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
  Added contrib/visupng directory (Willem van Schaik)
version 1.0.7beta18 [June 23, 2000]
  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
    and do not redefine PNGAPI if it is passed in via a compiler directive.
  Revised visupng/PngFile.c to remove returns from within the Try block.
  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
  Updated contrib/visupng/cexcept.h to version 1.0.0.
  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
version 1.0.7rc2 [June 28, 2000]
  Updated license to include disclaimers required by UCITA.
  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
version 1.0.7 [July 1, 2000]
  Revised the definition of "trans_values" in libpng.3/libpng.txt
version 1.0.8beta1 [July 8, 2000]
  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
     pngwutil.c.
  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
  Removed unused "#include <assert.h>" from png.c
  Added WindowsCE support.
  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
version 1.0.8beta2 [July 10, 2000]
  Added project files to the wince directory and made further revisions
     of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
version 1.0.8beta3 [July 11, 2000]
  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
     for indexed-color input files to avoid potential double-freeing trans array
     under some unusual conditions; problem was introduced in version 1.0.6f.
  Further revisions to pngtest.c and files in the wince subdirectory.
version 1.0.8beta4 [July 14, 2000]
  Added the files pngbar.png and pngbar.jpg to the distribution.
  Added makefile.cygwin, and cygwin support in pngconf.h
  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
version 1.0.8rc1 [July 16, 2000]
  Revised png_debug() macros and statements to eliminate compiler warnings.
version 1.0.8 [July 24, 2000]
  Added png_flush() in pngwrite.c, after png_write_IEND().
  Updated makefile.hpux to build a shared library.
version 1.0.9beta1 [November 10, 2000]
  Fixed typo in scripts/makefile.hpux
  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
  Changed "cdrom.com" in documentation to "libpng.org"
  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
  Changed type of "params" from voidp to png_voidp in png_read|write_png().
  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
  Revised the 3 instances of WRITEFILE in pngtest.c.
  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
  Updated png.rc in dll/msvc project
  Revised makefile.dec to define and use LIBPATH and INCPATH
  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
  Added a warning when application calls png_read_update_info() multiple times.
  Revised makefile.cygwin
  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
version 1.0.9beta2 [November 19, 2000]
  Renamed the "dll" subdirectory "projects".
  Added borland project files to "projects" subdirectory.
  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
  Add error message in png_set_compression_buffer_size() when malloc fails.
version 1.0.9beta3 [November 23, 2000]
  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
  Removed the png_flush() in pngwrite.c that crashes some applications
    that don't set png_output_flush_fn.
  Added makefile.macosx and makefile.aix to scripts directory.
version 1.0.9beta4 [December 1, 2000]
  Change png_chunk_warning to png_warning in png_check_keyword().
  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
version 1.0.9beta5 [December 15, 2000]
  Added support for filter method 64 (for PNG datastreams embedded in MNG).
version 1.0.9beta6 [December 18, 2000]
  Revised png_set_filter() to accept filter method 64 when appropriate.
  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
    help prevent applications from using MNG features in PNG datastreams.
  Added png_permit_mng_features() function.
  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
version 1.0.9rc1 [December 23, 2000]
  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
  Fixed error handling of unknown compression type in png_decompress_chunk().
  In pngconf.h, define __cdecl when _MSC_VER is defined.
version 1.0.9beta7 [December 28, 2000]
  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
  Revised memory management in png_set_hIST and png_handle_hIST in a backward
    compatible manner.  PLTE and tRNS were revised similarly.
  Revised the iCCP chunk reader to ignore trailing garbage.
version 1.0.9beta8 [January 12, 2001]
  Moved pngasmrd.h into pngconf.h.
  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
version 1.0.9beta9 [January 15, 2001]
  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
    wince and msvc project module definition files.
  Minor revision of makefile.cygwin.
  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
version 1.0.9beta10 [January 16, 2001]
  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
  Fixed "png_mmx_supported" typo in project definition files.
version 1.0.9beta11 [January 19, 2001]
  Updated makefile.sgi to make shared library.
  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
    by default, for the benefit of DLL forward compatibility.  These will
    be re-enabled in version 1.2.0.
version 1.0.9rc2 [January 22, 2001]
  Revised cygwin support.
version 1.0.9 [January 31, 2001]
  Added check of cygwin's ALL_STATIC in pngconf.h
  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
version 1.0.10beta1 [March 14, 2001]
  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
  Reformatted libpng.3 to eliminate bad line breaks.
  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
  Added prototype for png_mmx_support() near the top of pnggccrd.c
  Moved some error checking from png_handle_IHDR to png_set_IHDR.
  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
  Revised png_mmx_support() function in pnggccrd.c
  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
  Fixed memory leak in contrib/visupng/PngFile.c
  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
  Added warnings when retrieving or setting gamma=0.
  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
version 1.0.10rc1 [March 23, 2001]
  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
    and png_strlen.
  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
version 1.0.10 [March 30, 2001]
  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
  Added beos project files (Chris Herborth)
version 1.0.11beta1 [April 3, 2001]
  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
  Removed a no-longer needed AIX work-around from pngconf.h
  Changed several "//" single-line comments to C-style in pnggccrd.c
version 1.0.11beta2 [April 11, 2001]
  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
  Updated scripts/pngos2.def
version 1.0.11beta3 [April 14, 2001]
  Added checking the results of many instances of png_malloc() for NULL
version 1.0.11beta4 [April 20, 2001]
  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
    from user's malloc_fn().
  Removed some useless type casts of the NULL pointer.
  Added makefile.netbsd
version 1.0.11 [April 27, 2001]
  Revised makefile.netbsd
version 1.0.12beta1 [May 17, 2001]
  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
  Bumped DLLNUM to 2.
  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
  Eliminated the png_error about apps using png_read|write_init().  Instead,
    libpng will reallocate the png_struct and info_struct if they are too small.
    This achieves future binary compatibility for old applications written for
    libpng-0.88 and earlier.
  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
version 1.0.12rc1 [May 30, 2001]
  Check for missing profile length field in iCCP chunk and free chunk_data
     in case of truncated iCCP chunk.
  Updated makefile.sgi and makefile.sggcc
  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
     if user attempts to run it on an 8-bit display.
  Expanded the warnings about incompatible library and application.
  Added netware project, distributed in a separate zip file.
  Began distributing wince project in a separate zip file.
version 1.0.12 [June 8, 2001]
  Fixed new "PLTE_PERMITTED" typo (should be PLTE_SUPPORTED) in pngwutil.c.
  Updated contrib/gregbook

Send comments/corrections/commendations to
png-implement at ccrc.wustl.edu or to randeg at alum.rpi.edu

Glenn R-P

--- NEW FILE: example.c ---

#if 0 /* in case someone actually tries to compile this */

/* example.c - an example of using libpng */

/* This is an example of how to use libpng to read and write PNG files.
 * The file libpng.txt is much more verbose then this.  If you have not
 * read it, do so first.  This was designed to be a starting point of an
 * implementation.  This is not officially part of libpng, is hereby placed
 * in the public domain, and therefore does not require a copyright notice.
 *
 * This file does not currently compile, because it is missing certain
 * parts, like allocating memory to hold an image.  You will have to
 * supply these parts to get it to compile.  For an example of a minimal
 * working PNG reader/writer, see pngtest.c, included in this distribution;
 * see also the programs in the contrib directory.
 */

#include "png.h"

 /* The png_jmpbuf() macro, used in error handling, became available in
  * libpng version 1.0.6.  If you want to be able to run your code with older
  * versions of libpng, you must define the macro yourself (but only if it
  * is not already defined by libpng!).
  */

#ifndef png_jmpbuf
#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
#endif

/* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
 * returns zero if the image is a PNG and nonzero if it isn't a PNG.
 *
 * The function check_if_png() shown here, but not used, returns nonzero (true)
 * if the file can be opened and is a PNG, 0 (false) otherwise.
 *
 * If this call is successful, and you are going to keep the file open,
 * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
 * you have created the png_ptr, so that libpng knows your application
 * has read that many bytes from the start of the file.  Make sure you
 * don't call png_set_sig_bytes() with more than 8 bytes read or give it
 * an incorrect number of bytes read, or you will either have read too
 * many bytes (your fault), or you are telling libpng to read the wrong
 * number of magic bytes (also your fault).
 *
 * Many applications already read the first 2 or 4 bytes from the start
 * of the image to determine the file type, so it would be easiest just
 * to pass the bytes to png_sig_cmp() or even skip that if you know
 * you have a PNG file, and call png_set_sig_bytes().
 */
#define PNG_BYTES_TO_CHECK 4
int check_if_png(char *file_name, FILE **fp)
{
   char buf[PNG_BYTES_TO_CHECK];

   /* Open the prospective PNG file. */
   if ((*fp = fopen(file_name, "rb")) == NULL)
      return 0;

   /* Read in some of the signature bytes */
   if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
      return 0;

   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
      Return nonzero (true) if they match */

   return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
}

/* Read a PNG file.  You may want to return an error code if the read
 * fails (depending upon the failure).  There are two "prototypes" given
 * here - one where we are given the filename, and we need to open the
 * file, and the other where we are given an open file (possibly with
 * some or all of the magic bytes read - see comments above).
 */
#ifdef open_file /* prototype 1 */
void read_png(char *file_name)  /* We need to open the file */
{
   png_structp png_ptr;
   png_infop info_ptr;
   unsigned int sig_read = 0;
   png_uint_32 width, height;
   int bit_depth, color_type, interlace_type;
   FILE *fp;

   if ((fp = fopen(file_name, "rb")) == NULL)
      return (ERROR);
#else no_open_file /* prototype 2 */
void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
{
   png_structp png_ptr;
   png_infop info_ptr;
   png_uint_32 width, height;
   int bit_depth, color_type, interlace_type;
#endif no_open_file /* only use one prototype! */

   /* Create and initialize the png_struct with the desired error handler
    * functions.  If you want to use the default stderr and longjump method,
    * you can supply NULL for the last three parameters.  We also supply the
    * the compiler header file version, so that we know if the application
    * was compiled with a compatible version of the library.  REQUIRED
    */
   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
      png_voidp user_error_ptr, user_error_fn, user_warning_fn);

   if (png_ptr == NULL)
   {
      fclose(fp);
      return (ERROR);
   }

   /* Allocate/initialize the memory for image information.  REQUIRED. */
   info_ptr = png_create_info_struct(png_ptr);
   if (info_ptr == NULL)
   {
      fclose(fp);
      png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
      return (ERROR);
   }

   /* Set error handling if you are using the setjmp/longjmp method (this is
    * the normal method of doing things with libpng).  REQUIRED unless you
    * set up your own error handlers in the png_create_read_struct() earlier.
    */

   if (setjmp(png_jmpbuf(png_ptr)))
   {
      /* Free all of the memory associated with the png_ptr and info_ptr */
      png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
      fclose(fp);
      /* If we get here, we had a problem reading the file */
      return (ERROR);
   }

   /* One of the following I/O initialization methods is REQUIRED */
#ifdef streams /* PNG file I/O method 1 */
   /* Set up the input control if you are using standard C streams */
   png_init_io(png_ptr, fp);

#else no_streams /* PNG file I/O method 2 */
   /* If you are using replacement read functions, instead of calling
    * png_init_io() here you would call:
    */
   png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
   /* where user_io_ptr is a structure you want available to the callbacks */
#endif no_streams /* Use only one I/O method! */

   /* If we have already read some of the signature */
   png_set_sig_bytes(png_ptr, sig_read);

#ifdef hilevel
   /*
    * If you have enough memory to read in the entire image at once,
    * and you need to specify only transforms that can be controlled
    * with one of the PNG_TRANSFORM_* bits (this presently excludes
    * dithering, filling, setting background, and doing gamma
    * adjustment), then you can read the entire image (including
    * pixels) into the info structure with this call:
    */
   png_read_png(png_ptr, info_ptr, png_transforms, NULL);
#else
   /* OK, you're doing it the hard way, with the lower-level functions */

   /* The call to png_read_info() gives us all of the information from the
    * PNG file before the first IDAT (image data chunk).  REQUIRED
    */
   png_read_info(png_ptr, info_ptr);

   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
       &interlace_type, NULL, NULL);

/**** Set up the data transformations you want.  Note that these are all
 **** optional.  Only call them if you want/need them.  Many of the
 **** transformations only work on specific types of images, and many
 **** are mutually exclusive.
 ****/

   /* tell libpng to strip 16 bit/color files down to 8 bits/color */
   png_set_strip_16(png_ptr);

   /* Strip alpha bytes from the input data without combining with the
    * background (not recommended).
    */
   png_set_strip_alpha(png_ptr);

   /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
    * byte into separate bytes (useful for paletted and grayscale images).
    */
   png_set_packing(png_ptr);

   /* Change the order of packed pixels to least significant bit first
    * (not useful if you are using png_set_packing). */
   png_set_packswap(png_ptr);

   /* Expand paletted colors into true RGB triplets */
   if (color_type == PNG_COLOR_TYPE_PALETTE)
      png_set_expand(png_ptr);

   /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
      png_set_expand(png_ptr);

   /* Expand paletted or RGB images with transparency to full alpha channels
    * so the data will be available as RGBA quartets.
    */
   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
      png_set_expand(png_ptr);

   /* Set the background color to draw transparent and alpha images over.
    * It is possible to set the red, green, and blue components directly
    * for paletted images instead of supplying a palette index.  Note that
    * even if the PNG file supplies a background, you are not required to
    * use it - you should use the (solid) application background if it has one.
    */

   png_color_16 my_background, *image_background;

   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
      png_set_background(png_ptr, image_background,
                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
   else
      png_set_background(png_ptr, &my_background,
                         PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);

   /* Some suggestions as to how to get a screen gamma value */

   /* Note that screen gamma is the display_exponent, which includes
    * the CRT_exponent and any correction for viewing conditions */
   if (/* We have a user-defined screen gamma value */)
   {
      screen_gamma = user-defined screen_gamma;
   }
   /* This is one way that applications share the same screen gamma value */
   else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
   {
      screen_gamma = atof(gamma_str);
   }
   /* If we don't have another value */
   else
   {
      screen_gamma = 2.2;  /* A good guess for a PC monitors in a dimly
                              lit room */
      screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
   }

   /* Tell libpng to handle the gamma conversion for you.  The final call
    * is a good guess for PC generated images, but it should be configurable
    * by the user at run time by the user.  It is strongly suggested that
    * your application support gamma correction.
    */

   int intent;

   if (png_get_sRGB(png_ptr, info_ptr, &intent))
      png_set_gamma(png_ptr, screen_gamma, 0.45455);
   else
   {
      double image_gamma;
      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
         png_set_gamma(png_ptr, screen_gamma, image_gamma);
      else
         png_set_gamma(png_ptr, screen_gamma, 0.45455);
   }

   /* Dither RGB files down to 8 bit palette or reduce palettes
    * to the number of colors available on your screen.
    */
   if (color_type & PNG_COLOR_MASK_COLOR)
   {
      int num_palette;
      png_colorp palette;

      /* This reduces the image to the application supplied palette */
      if (/* we have our own palette */)
      {
         /* An array of colors to which the image should be dithered */
         png_color std_color_cube[MAX_SCREEN_COLORS];

         png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
            MAX_SCREEN_COLORS, NULL, 0);
      }
      /* This reduces the image to the palette supplied in the file */
      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
      {
         png_uint_16p histogram;

         png_get_hIST(png_ptr, info_ptr, &histogram);

         png_set_dither(png_ptr, palette, num_palette,
                        max_screen_colors, histogram, 0);
      }
   }

   /* invert monochrome files to have 0 as white and 1 as black */
   png_set_invert_mono(png_ptr);

   /* If you want to shift the pixel values from the range [0,255] or
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
   {
      png_color_8p sig_bit;

      png_get_sBIT(png_ptr, info_ptr, &sig_bit);
      png_set_shift(png_ptr, sig_bit);
   }

   /* flip the RGB pixels to BGR (or RGBA to BGRA) */
   if (color_type & PNG_COLOR_MASK_COLOR)
      png_set_bgr(png_ptr);

   /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
   png_set_swap_alpha(png_ptr);

   /* swap bytes of 16 bit files to least significant byte first */
   png_set_swap(png_ptr);

   /* Add filler (or alpha) byte (before/after each RGB triplet) */
   png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);

   /* Turn on interlace handling.  REQUIRED if you are not using
    * png_read_image().  To see how to handle interlacing passes,
    * see the png_read_row() method below:
    */
   number_passes = png_set_interlace_handling(png_ptr);

   /* Optional call to gamma correct and add the background to the palette
    * and update info structure.  REQUIRED if you are expecting libpng to
    * update the palette for you (ie you selected such a transform above).
    */
   png_read_update_info(png_ptr, info_ptr);

   /* Allocate the memory to hold the image using the fields of info_ptr. */

   /* The easiest way to read the image: */
   png_bytep row_pointers[height];

   for (row = 0; row < height; row++)
   {
      row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
         info_ptr));
   }

   /* Now it's time to read the image.  One of these methods is REQUIRED */
#ifdef entire /* Read the entire image in one go */
   png_read_image(png_ptr, row_pointers);

#else no_entire /* Read the image one or more scanlines at a time */
   /* The other way to read images - deal with interlacing: */

   for (pass = 0; pass < number_passes; pass++)
   {
#ifdef single /* Read the image a single row at a time */
      for (y = 0; y < height; y++)
      {
         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
      }

#else no_single /* Read the image several rows at a time */
      for (y = 0; y < height; y += number_of_rows)
      {
#ifdef sparkle /* Read the image using the "sparkle" effect. */
         png_read_rows(png_ptr, &row_pointers[y], NULL, number_of_rows);

         png_read_rows(png_ptr, NULL, row_pointers[y], number_of_rows);
#else no_sparkle /* Read the image using the "rectangle" effect */
         png_read_rows(png_ptr, NULL, &row_pointers[y], number_of_rows);
#endif no_sparkle /* use only one of these two methods */
      }

      /* if you want to display the image after every pass, do
         so here */
#endif no_single /* use only one of these two methods */
   }
#endif no_entire /* use only one of these two methods */

   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
   png_read_end(png_ptr, info_ptr);
#endif hilevel

   /* At this point you have read the entire image */

   /* clean up after the read, and free any memory allocated - REQUIRED */
   png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);

   /* close the file */
   fclose(fp);

   /* that's it */
   return (OK);
}

/* progressively read a file */

int
initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
{
   /* Create and initialize the png_struct with the desired error handler
    * functions.  If you want to use the default stderr and longjump method,
    * you can supply NULL for the last three parameters.  We also check that
    * the library version is compatible in case we are using dynamically
    * linked libraries.
    */
   *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
       png_voidp user_error_ptr, user_error_fn, user_warning_fn);

   if (*png_ptr == NULL)
   {
      *info_ptr = NULL;
      return (ERROR);
   }

   *info_ptr = png_create_info_struct(png_ptr);

   if (*info_ptr == NULL)
   {
      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
      return (ERROR);
   }

   if (setjmp(png_jmpbuf((*png_ptr))))
   {
      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
      return (ERROR);
   }

   /* This one's new.  You will need to provide all three
    * function callbacks, even if you aren't using them all.
    * If you aren't using all functions, you can specify NULL
    * parameters.  Even when all three functions are NULL,
    * you need to call png_set_progressive_read_fn().
    * These functions shouldn't be dependent on global or
    * static variables if you are decoding several images
    * simultaneously.  You should store stream specific data
    * in a separate struct, given as the second parameter,
    * and retrieve the pointer from inside the callbacks using
    * the function png_get_progressive_ptr(png_ptr).
    */
   png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
      info_callback, row_callback, end_callback);

   return (OK);
}

int
process_data(png_structp *png_ptr, png_infop *info_ptr,
   png_bytep buffer, png_uint_32 length)
{
   if (setjmp(png_jmpbuf((*png_ptr))))
   {
      /* Free the png_ptr and info_ptr memory on error */
      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
      return (ERROR);
   }

   /* This one's new also.  Simply give it chunks of data as
    * they arrive from the data stream (in order, of course).
    * On Segmented machines, don't give it any more than 64K.
    * The library seems to run fine with sizes of 4K, although
    * you can give it much less if necessary (I assume you can
    * give it chunks of 1 byte, but I haven't tried with less
    * than 256 bytes yet).  When this function returns, you may
    * want to display any rows that were generated in the row
    * callback, if you aren't already displaying them there.
    */
   png_process_data(*png_ptr, *info_ptr, buffer, length);
   return (OK);
}

info_callback(png_structp png_ptr, png_infop info)
{
/* do any setup here, including setting any of the transformations
 * mentioned in the Reading PNG files section.  For now, you _must_
 * call either png_start_read_image() or png_read_update_info()
 * after all the transformations are set (even if you don't set
 * any).  You may start getting rows before png_process_data()
 * returns, so this is your last chance to prepare for that.
 */
}

row_callback(png_structp png_ptr, png_bytep new_row,
   png_uint_32 row_num, int pass)
{
/* this function is called for every row in the image.  If the
 * image is interlacing, and you turned on the interlace handler,
 * this function will be called for every row in every pass.
 * Some of these rows will not be changed from the previous pass.
 * When the row is not changed, the new_row variable will be NULL.
 * The rows and passes are called in order, so you don't really
 * need the row_num and pass, but I'm supplying them because it
 * may make your life easier.
 *
 * For the non-NULL rows of interlaced images, you must call
 * png_progressive_combine_row() passing in the row and the
 * old row.  You can call this function for NULL rows (it will
 * just return) and for non-interlaced images (it just does the
 * png_memcpy for you) if it will make the code easier.  Thus, you
 * can just do this for all cases:
 */

   png_progressive_combine_row(png_ptr, old_row, new_row);

/* where old_row is what was displayed for previous rows.  Note
 * that the first pass (pass == 0 really) will completely cover
 * the old row, so the rows do not have to be initialized.  After
 * the first pass (and only for interlaced images), you will have
 * to pass the current row, and the function will combine the
 * old row and the new row.
 */
}

end_callback(png_structp png_ptr, png_infop info)
{
/* this function is called when the whole image has been read,
 * including any chunks after the image (up to and including
 * the IEND).  You will usually have the same info chunk as you
 * had in the header, although some data may have been added
 * to the comments and time fields.
 *
 * Most people won't do much here, perhaps setting a flag that
 * marks the image as finished.
 */
}

/* write a png file */
void write_png(char *file_name /* , ... other image information ... */)
{
   FILE *fp;
   png_structp png_ptr;
   png_infop info_ptr;
   png_colorp palette;

   /* open the file */
   fp = fopen(file_name, "wb");
   if (fp == NULL)
      return (ERROR);

   /* Create and initialize the png_struct with the desired error handler
    * functions.  If you want to use the default stderr and longjump method,
    * you can supply NULL for the last three parameters.  We also check that
    * the library version is compatible with the one used at compile time,
    * in case we are using dynamically linked libraries.  REQUIRED.
    */
   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
      png_voidp user_error_ptr, user_error_fn, user_warning_fn);

   if (png_ptr == NULL)
   {
      fclose(fp);
      return (ERROR);
   }

   /* Allocate/initialize the image information data.  REQUIRED */
   info_ptr = png_create_info_struct(png_ptr);
   if (info_ptr == NULL)
   {
      fclose(fp);
      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
      return (ERROR);
   }

   /* Set error handling.  REQUIRED if you aren't supplying your own
    * error handling functions in the png_create_write_struct() call.
    */
   if (setjmp(png_jmpbuf(png_ptr)))
   {
      /* If we get here, we had a problem reading the file */
      fclose(fp);
      png_destroy_write_struct(&png_ptr, &info_ptr);
      return (ERROR);
   }

   /* One of the following I/O initialization functions is REQUIRED */
#ifdef streams /* I/O initialization method 1 */
   /* set up the output control if you are using standard C streams */
   png_init_io(png_ptr, fp);
#else no_streams /* I/O initialization method 2 */
   /* If you are using replacement read functions, instead of calling
    * png_init_io() here you would call */
   png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
      user_IO_flush_function);
   /* where user_io_ptr is a structure you want available to the callbacks */
#endif no_streams /* only use one initialization method */

#ifdef hilevel
   /* This is the easy way.  Use it if you already have all the
    * image info living info in the structure.  You could "|" many
    * PNG_TRANSFORM flags into the png_transforms integer here.
    */
   png_write_png(png_ptr, info_ptr, png_transforms, NULL);
#else
   /* This is the hard way */

   /* Set the image information here.  Width and height are up to 2^31,
    * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
    * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
    * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
    * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
    * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
    */
   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???,
      PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);

   /* set the palette if there is one.  REQUIRED for indexed-color images */
   palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
             * sizeof (png_color));
   /* ... set palette colors ... */
   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
   /* You must not free palette here, because png_set_PLTE only makes a link to
      the palette that you malloced.  Wait until you are about to destroy
      the png structure. */

   /* optional significant bit chunk */
   /* if we are dealing with a grayscale image then */
   sig_bit.gray = true_bit_depth;
   /* otherwise, if we are dealing with a color image then */
   sig_bit.red = true_red_bit_depth;
   sig_bit.green = true_green_bit_depth;
   sig_bit.blue = true_blue_bit_depth;
   /* if the image has an alpha channel then */
   sig_bit.alpha = true_alpha_bit_depth;
   png_set_sBIT(png_ptr, info_ptr, sig_bit);


   /* Optional gamma chunk is strongly suggested if you have any guess
    * as to the correct gamma of the image.
    */
   png_set_gAMA(png_ptr, info_ptr, gamma);

   /* Optionally write comments into the image */
   text_ptr[0].key = "Title";
   text_ptr[0].text = "Mona Lisa";
   text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
   text_ptr[1].key = "Author";
   text_ptr[1].text = "Leonardo DaVinci";
   text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
   text_ptr[2].key = "Description";
   text_ptr[2].text = "<long text>";
   text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
#ifdef PNG_iTXt_SUPPORTED
   text_ptr[0].lang = NULL;
   text_ptr[1].lang = NULL;
   text_ptr[2].lang = NULL;
#endif
   png_set_text(png_ptr, info_ptr, text_ptr, 3);

   /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */
   /* note that if sRGB is present the gAMA and cHRM chunks must be ignored
    * on read and must be written in accordance with the sRGB profile */

   /* Write the file header information.  REQUIRED */
   png_write_info(png_ptr, info_ptr);

   /* If you want, you can write the info in two steps, in case you need to
    * write your private chunk ahead of PLTE:
    *
    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
    *   write_my_chunk();
    *   png_write_info(png_ptr, info_ptr);
    *
    * However, given the level of known- and unknown-chunk support in 1.1.0
    * and up, this should no longer be necessary.
    */

   /* Once we write out the header, the compression type on the text
    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    * at the end.
    */

   /* set up the transformations you want.  Note that these are
    * all optional.  Only call them if you want them.
    */

   /* invert monochrome pixels */
   png_set_invert_mono(png_ptr);

   /* Shift the pixels up to a legal bit depth and fill in
    * as appropriate to correctly scale the image.
    */
   png_set_shift(png_ptr, &sig_bit);

   /* pack pixels into bytes */
   png_set_packing(png_ptr);

   /* swap location of alpha bytes from ARGB to RGBA */
   png_set_swap_alpha(png_ptr);

   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
    * RGB (4 channels -> 3 channels). The second parameter is not used.
    */
   png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);

   /* flip BGR pixels to RGB */
   png_set_bgr(png_ptr);

   /* swap bytes of 16-bit files to most significant byte first */
   png_set_swap(png_ptr);

   /* swap bits of 1, 2, 4 bit packed pixel formats */
   png_set_packswap(png_ptr);

   /* turn on interlace handling if you are not using png_write_image() */
   if (interlacing)
      number_passes = png_set_interlace_handling(png_ptr);
   else
      number_passes = 1;

   /* The easiest way to write the image (you may have a different memory
    * layout, however, so choose what fits your needs best).  You need to
    * use the first method if you aren't handling interlacing yourself.
    */
   png_uint_32 k, height, width;
   png_byte image[height][width*bytes_per_pixel];
   png_bytep row_pointers[height];
   for (k = 0; k < height; k++)
     row_pointers[k] = image + k*width*bytes_per_pixel;

   /* One of the following output methods is REQUIRED */
#ifdef entire /* write out the entire image data in one call */
   png_write_image(png_ptr, row_pointers);

   /* the other way to write the image - deal with interlacing */

#else no_entire /* write out the image data by one or more scanlines */
   /* The number of passes is either 1 for non-interlaced images,
    * or 7 for interlaced images.
    */
   for (pass = 0; pass < number_passes; pass++)
   {
      /* Write a few rows at a time. */
      png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);

      /* If you are only writing one row at a time, this works */
      for (y = 0; y < height; y++)
      {
         png_write_rows(png_ptr, &row_pointers[y], 1);
      }
   }
#endif no_entire /* use only one output method */

   /* You can write optional chunks like tEXt, zTXt, and tIME at the end
    * as well.  Shouldn't be necessary in 1.1.0 and up as all the public
    * chunks are supported and you can use png_set_unknown_chunks() to
    * register unknown chunks into the info structure to be written out.
    */

   /* It is REQUIRED to call this to finish writing the rest of the file */
   png_write_end(png_ptr, info_ptr);
#endif hilevel

   /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
      as recommended in versions 1.0.5m and earlier of this example; if
      libpng mallocs info_ptr->palette, libpng will free it).  If you
      allocated it with malloc() instead of png_malloc(), use free() instead
      of png_free(). */
   png_free(png_ptr, palette);
   palette=NULL;

   /* Similarly, if you png_malloced any data that you passed in with
      png_set_something(), such as a hist or trans array, free it here,
      when you can be sure that libpng is through with it. */
   png_free(png_ptr, trans);
   trans=NULL;

   /* clean up after the write, and free any memory allocated */
   png_destroy_write_struct(&png_ptr, &info_ptr);

   /* close the file */
   fclose(fp);

   /* that's it */
   return (OK);
}

#endif /* if 0 */

--- NEW FILE: libpngpf.3 ---
.TH LIBPNGPF 3 "June 8, 2001"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12
(private functions)
.SH SYNOPSIS
\fB#include <png.h>\fP

\fI\fB

\fBvoid png_build_gamma_table (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP

\fI\fB

\fBvoid png_calculate_crc (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIptr\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_check_chunk_name (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP

\fI\fB

\fBpng_size_t png_check_keyword (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charpp \fInew_key\fP\fB);\fP

\fI\fB

\fBvoid png_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fImask\fP\fB);\fP

\fI\fB

\fBvoid png_correct_palette (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP

\fI\fB

\fBint png_crc_error (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBint png_crc_finish (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIskip\fP\fB);\fP

\fI\fB

\fBvoid png_crc_read (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuf\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fI\fB

\fBpng_voidp png_create_struct (int \fP\fItype\fP\fB, png_malloc_ptr \fImalloc_fn\fP\fB);\fP

\fI\fB

\fBpng_voidp png_create_struct_2 (int \fItype\fP\fB);\fP

\fI\fB

\fBpng_charp png_decompress_chunk (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcomp_type\fP\fB, png_charp \fP\fIchunkdata\fP\fB, png_size_t \fP\fIchunklength\fP\fB, png_size_t \fP\fIprefix_length\fP\fB, png_size_t \fI*data_length\fP\fB);\fP

\fI\fB

\fBvoid png_destroy_struct (png_voidp \fIstruct_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_destroy_struct_2 (png_voidp \fP\fIstruct_ptr\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP

\fI\fB

\fBvoid png_do_background (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_16p \fP\fItrans_values\fP\fB, png_color_16p \fP\fIbackground\fP\fB, png_color_16p \fP\fIbackground_1\fP\fB, png_bytep \fP\fIgamma_table\fP\fB, png_bytep \fP\fIgamma_from_1\fP\fB, png_bytep \fP\fIgamma_to_1\fP\fB, png_uint_16pp \fP\fIgamma_16\fP\fB, png_uint_16pp \fP\fIgamma_16_from_1\fP\fB, png_uint_16pp \fP\fIgamma_16_to_1\fP\fB, int \fIgamma_shift\fP\fB);\fP

\fI\fB

\fBvoid png_do_bgr (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_chop (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_dither (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIpalette_lookup\fP\fB, png_bytep \fIdither_lookup\fP\fB);\fP

\fI\fB

\fBvoid png_do_expand (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_16p \fItrans_value\fP\fB);\fP

\fI\fB

\fBvoid png_do_expand_palette (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_colorp \fP\fIpalette\fP\fB, png_bytep \fP\fItrans\fP\fB, int \fInum_trans\fP\fB);\fP

\fI\fB

\fBvoid png_do_gamma (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIgamma_table\fP\fB, png_uint_16pp \fP\fIgamma_16_table\fP\fB, int \fIgamma_shift\fP\fB);\fP

\fI\fB

\fBvoid png_do_gray_to_rgb (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_invert (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_pack (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fIbit_depth\fP\fB);\fP

\fI\fB

\fBvoid png_do_packswap (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_read_filler (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, png_uint_32 \fIflags\fP\fB);\fP

\fI\fB

\fBvoid png_do_read_interlace (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fP\fIpass\fP\fB, png_uint_32 \fItransformations\fP\fB);\fP

\fI\fB

\fBvoid png_do_read_invert_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_read_swap_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_read_transformations (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBint png_do_rgb_to_gray (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_shift (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_8p \fIbit_depth\fP\fB);\fP

\fI\fB

\fBvoid png_do_strip_filler (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fIflags\fP\fB);\fP

\fI\fB

\fBvoid png_do_swap (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_unpack (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_unshift (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_8p \fIsig_bits\fP\fB);\fP

\fI\fB

\fBvoid png_do_write_interlace (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fIpass\fP\fB);\fP

\fI\fB

\fBvoid png_do_write_invert_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_write_swap_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_do_write_transformations (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid *png_far_to_near (png_structp png_ptr,png_voidp \fP\fIptr\fP\fB, int \fIcheck\fP\fB);\fP

\fI\fB

\fBvoid png_flush (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP

\fI\fB

\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP

\fI\fB

\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP

\fI\fB

\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP

\fI\fB

\fBvoid png_handle_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_IEND (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_iTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_handle_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_info_destroy (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_init_read_transformations (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_process_IDAT_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_length\fP\fB);\fP

\fI\fB

\fBvoid png_process_some_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_check_crc (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_crc_finish (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_crc_skip (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_push_fill_buffer (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_push_handle_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_push_handle_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_push_handle_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_push_have_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_have_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_have_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP

\fI\fB

\fBvoid png_push_process_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_IDAT (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_sig (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_read_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_push_restore_buffer (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_length\fP\fB);\fP

\fI\fB

\fBvoid png_push_save_buffer (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_read_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_read_filter_row (png_structp \fP\fIpng_ptr\fP\fB, png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIprev_row\fP\fB, int \fIfilter\fP\fB);\fP

\fI\fB

\fBvoid png_read_finish_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_read_push_finish_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_read_start_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_read_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_reset_crc (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP

\fI\fB

\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP

\fI\fB

\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP

\fI\fB

\fBvoid png_write_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIvalues\fP\fB, int \fIcolor_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_cHRM (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP

\fI\fB

\fBvoid png_write_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP

\fI\fB

\fBvoid png_write_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fBvoid png_write_filtered_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIfiltered_row\fP\fB);\fP

\fI\fB

\fBvoid png_write_find_filter (png_structp \fP\fIpng_ptr\fP\fB, png_row_infop \fIrow_info\fP\fB);\fP

\fI\fB

\fBvoid png_write_finish_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_write_gAMA (png_structp \fP\fIpng_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP

\fI\fB

\fBvoid png_write_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIint_file_gamma\fP\fB);\fP

\fI\fB

\fBvoid png_write_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_uint_16p \fP\fIhist\fP\fB, int \fInum_hist\fP\fB);\fP

\fI\fB

\fBvoid png_write_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_charp \fP\fIprofile\fP\fB, int \fIproflen\fP\fB);\fP

\fI\fB

\fBvoid png_write_IDAT (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP

\fI\fB

\fBvoid png_write_IEND (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_write_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fP\fIfilter_type\fP\fB, int \fIinterlace_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_iTXt (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcompression\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fIlang\fP\fB, png_charp \fP\fItranslated_key\fP\fB, png_charp \fItext)\fP\fB);\fP

\fI\fB

\fBvoid png_write_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIx_offset\fP\fB, png_uint_32 \fP\fIy_offset\fP\fB, int \fIunit_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP

\fI\fB

\fBvoid png_write_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIx_pixels_per_unit\fP\fB, png_uint_32 \fP\fIy_pixels_per_unit\fP\fB, int \fIunit_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, png_uint_32 \fInum_pal\fP\fB);\fP

\fI\fB

\fBvoid png_write_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fP\fIsbit\fP\fB, int \fIcolor_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP

\fI\fB

\fBvoid png_write_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP

\fI\fB

\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_write_sRGB (png_structp \fP\fIpng_ptr\fP\fB, int \fIintent\fP\fB);\fP

\fI\fB

\fBvoid png_write_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_spalette_p \fIpalette\fP\fB);\fP

\fI\fB

\fBvoid png_write_start_row (png_structp \fIpng_ptr\fP\fB);\fP

\fI\fB

\fBvoid png_write_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fItext\fP\fB, png_size_t \fItext_len\fP\fB);\fP

\fI\fB

\fBvoid png_write_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP

\fI\fB

\fBvoid png_write_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fItrans\fP\fB, png_color_16p \fP\fIvalues\fP\fB, int \fP\fInumber\fP\fB, int \fIcolor_type\fP\fB);\fP

\fI\fB

\fBvoid png_write_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fItext\fP\fB, png_size_t \fP\fItext_len\fP\fB, int \fIcompression\fP\fB);\fP

\fI\fB

\fBvoidpf png_zalloc (voidpf \fP\fIpng_ptr\fP\fB, uInt \fP\fIitems\fP\fB, uInt \fIsize\fP\fB);\fP

\fI\fB

\fBvoid png_zfree (voidpf \fP\fIpng_ptr\fP\fB, voidpf \fIptr\fP\fB);\fP

\fI\fB

.SH DESCRIPTION
The functions listed above are used privately by libpng
and are not recommended for use by applications.  They
are listed alphabetically here as an aid to libpng maintainers.
See png.h for more information on these functions.

.SH SEE ALSO
libpng(3), png(5)
.SH AUTHOR
Glenn Randers-Pehrson

--- NEW FILE: pngtest.c ---

/* pngtest.c - a simple test program to test libpng
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This program reads in a PNG image, writes it out again, and then
 * compares the two files.  If the files are identical, this shows that
 * the basic chunk handling, filtering, and (de)compression code is working
 * properly.  It does not currently test all of the transforms, although
 * it probably should.
 *
 * The program will report "FAIL" in certain legitimate cases:
 * 1) when the compression level or filter selection method is changed.
 * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192.
 * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks
[...1475 lines suppressed...]
   t_start = t_stop;
   fprintf(STDERR," CPU time used = %.3f seconds",
      (t_misc+t_decode+t_encode)/(float)CLOCKS_PER_SEC);
   fprintf(STDERR," (decoding %.3f,\n",
      t_decode/(float)CLOCKS_PER_SEC);
   fprintf(STDERR,"        encoding %.3f ,",
      t_encode/(float)CLOCKS_PER_SEC);
   fprintf(STDERR," other %.3f seconds)\n\n",
      t_misc/(float)CLOCKS_PER_SEC);
#endif

   if (ierror == 0)
      fprintf(STDERR, "libpng passes test\n");
   else
      fprintf(STDERR, "libpng FAILS test\n");
   return (int)(ierror != 0);
}

/* Generate a compiler error if there is an old png.h in the search path. */
typedef version_1_0_12 your_png_h_is_not_version_1_0_12;

--- NEW FILE: pngmem.c ---

/* pngmem.c - stub functions for memory allocation
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file provides a location for all memory allocation.  Users who
 * need special memory handling are expected to supply replacement
 * functions for png_malloc() and png_free(), and to use
 * png_create_read_struct_2() and png_create_write_struct_2() to
 * identify the replacement functions.
 */

#define PNG_INTERNAL
#include "png.h"

/* Borland DOS special memory handler */
#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
/* if you change this, be sure to change the one in png.h also */

/* Allocate memory for a png_struct.  The malloc and memset can be replaced
   by a single call to calloc() if this is thought to improve performance. */
png_voidp /* PRIVATE */
png_create_struct(int type)
{
#ifdef PNG_USER_MEM_SUPPORTED
   return (png_create_struct_2(type, NULL, NULL));
}

/* Alternate version of png_create_struct, for use with user-defined malloc. */
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
{
#endif /* PNG_USER_MEM_SUPPORTED */
   png_size_t size;
   png_voidp struct_ptr;

   if (type == PNG_STRUCT_INFO)
     size = sizeof(png_info);
   else if (type == PNG_STRUCT_PNG)
     size = sizeof(png_struct);
   else
     return ((png_voidp)NULL);

#ifdef PNG_USER_MEM_SUPPORTED
   if(malloc_fn != NULL)
   {
      if (mem_ptr != NULL)
      {
         png_struct dummy_struct;
         png_structp png_ptr = &dummy_struct;
         png_ptr->mem_ptr=mem_ptr;
         struct_ptr = (*(malloc_fn))(png_ptr, size);
      }
      else
         struct_ptr = (*(malloc_fn))(NULL, size);
      if (struct_ptr != NULL)
         png_memset(struct_ptr, 0, size);
      return (struct_ptr);
   }
#endif /* PNG_USER_MEM_SUPPORTED */
   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
   {
      png_memset(struct_ptr, 0, size);
   }
   return (struct_ptr);
}


/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)
{
#ifdef PNG_USER_MEM_SUPPORTED
   png_destroy_struct_2(struct_ptr, (png_free_ptr)NULL, (png_voidp)NULL);
}

/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
    png_voidp mem_ptr)
{
#endif
   if (struct_ptr != NULL)
   {
#ifdef PNG_USER_MEM_SUPPORTED
      if(free_fn != NULL)
      {
         png_struct dummy_struct;
         png_structp png_ptr = &dummy_struct;
         png_ptr->mem_ptr=mem_ptr;
         (*(free_fn))(png_ptr, struct_ptr);
         return;
      }
#endif /* PNG_USER_MEM_SUPPORTED */
      farfree (struct_ptr);
   }
}

/* Allocate memory.  For reasonable files, size should never exceed
 * 64K.  However, zlib may allocate more then 64K if you don't tell
 * it not to.  See zconf.h and png.h for more information. zlib does
 * need to allocate exactly 64K, so whatever you call here must
 * have the ability to do that.
 *
 * Borland seems to have a problem in DOS mode for exactly 64K.
 * It gives you a segment with an offset of 8 (perhaps to store its
 * memory stuff).  zlib doesn't like this at all, so we have to
 * detect and deal with it.  This code should not be needed in
 * Windows or OS/2 modes, and only in 16 bit mode.  This code has
 * been updated by Alexander Lehmann for version 0.89 to waste less
 * memory.
 *
 * Note that we can't use png_size_t for the "size" declaration,
 * since on some systems a png_size_t is a 16-bit quantity, and as a
 * result, we would be truncating potentially larger memory requests
 * (which should cause a fatal error) and introducing major problems.
 */
png_voidp PNGAPI
png_malloc(png_structp png_ptr, png_uint_32 size)
{
#ifndef PNG_USER_MEM_SUPPORTED
   png_voidp ret;
#endif
   if (png_ptr == NULL || size == 0)
      return ((png_voidp)NULL);

#ifdef PNG_USER_MEM_SUPPORTED
   if(png_ptr->malloc_fn != NULL)
   {
       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
       if (ret == NULL)
          png_error(png_ptr, "Out of memory!");
       return (ret);
   }
   else
       return png_malloc_default(png_ptr, size);
}

png_voidp PNGAPI
png_malloc_default(png_structp png_ptr, png_uint_32 size)
{
   png_voidp ret;
#endif /* PNG_USER_MEM_SUPPORTED */

#ifdef PNG_MAX_MALLOC_64K
   if (size > (png_uint_32)65536L)
      png_error(png_ptr, "Cannot Allocate > 64K");
#endif

   if (size == (png_uint_32)65536L)
   {
      if (png_ptr->offset_table == NULL)
      {
         /* try to see if we need to do any of this fancy stuff */
         ret = farmalloc(size);
         if (ret == NULL || ((png_size_t)ret & 0xffff))
         {
            int num_blocks;
            png_uint_32 total_size;
            png_bytep table;
            int i;
            png_byte huge * hptr;

            if (ret != NULL)
            {
               farfree(ret);
               ret = NULL;
            }

            if(png_ptr->zlib_window_bits > 14)
               num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
            else
               num_blocks = 1;
            if (png_ptr->zlib_mem_level >= 7)
               num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
            else
               num_blocks++;

            total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;

            table = farmalloc(total_size);

            if (table == NULL)
            {
               png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
            }

            if ((png_size_t)table & 0xfff0)
            {
               png_error(png_ptr, "Farmalloc didn't return normalized pointer");
            }

            png_ptr->offset_table = table;
            png_ptr->offset_table_ptr = farmalloc(num_blocks *
               sizeof (png_bytep));

            if (png_ptr->offset_table_ptr == NULL)
            {
               png_error(png_ptr, "Out Of memory.");
            }

            hptr = (png_byte huge *)table;
            if ((png_size_t)hptr & 0xf)
            {
               hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
               hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
            }
            for (i = 0; i < num_blocks; i++)
            {
               png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
               hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
            }

            png_ptr->offset_table_number = num_blocks;
            png_ptr->offset_table_count = 0;
            png_ptr->offset_table_count_free = 0;
         }
      }

      if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
         png_error(png_ptr, "Out of Memory.");

      ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
   }
   else
      ret = farmalloc(size);

   if (ret == NULL)
   {
      png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
   }

   return (ret);
}

/* free a pointer allocated by png_malloc().  In the default
   configuration, png_ptr is not used, but is passed in case it
   is needed.  If ptr is NULL, return without taking any action. */
void PNGAPI
png_free(png_structp png_ptr, png_voidp ptr)
{
   if (png_ptr == NULL || ptr == NULL)
      return;

#ifdef PNG_USER_MEM_SUPPORTED
   if (png_ptr->free_fn != NULL)
   {
      (*(png_ptr->free_fn))(png_ptr, ptr);
      return;
   }
   else png_free_default(png_ptr, ptr);
}

void PNGAPI
png_free_default(png_structp png_ptr, png_voidp ptr)
{
#endif /* PNG_USER_MEM_SUPPORTED */

   if (png_ptr->offset_table != NULL)
   {
      int i;

      for (i = 0; i < png_ptr->offset_table_count; i++)
      {
         if (ptr == png_ptr->offset_table_ptr[i])
         {
            ptr = NULL;
            png_ptr->offset_table_count_free++;
            break;
         }
      }
      if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
      {
         farfree(png_ptr->offset_table);
         farfree(png_ptr->offset_table_ptr);
         png_ptr->offset_table = NULL;
         png_ptr->offset_table_ptr = NULL;
      }
   }

   if (ptr != NULL)
   {
      farfree(ptr);
   }
}

#else /* Not the Borland DOS special memory handler */

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably.*/
png_voidp /* PRIVATE */
png_create_struct(int type)
{
#ifdef PNG_USER_MEM_SUPPORTED
   return (png_create_struct_2(type, NULL, NULL));
}

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably.*/
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
{
#endif /* PNG_USER_MEM_SUPPORTED */
   png_size_t size;
   png_voidp struct_ptr;

   if (type == PNG_STRUCT_INFO)
      size = sizeof(png_info);
   else if (type == PNG_STRUCT_PNG)
      size = sizeof(png_struct);
   else
      return ((png_voidp)NULL);

#ifdef PNG_USER_MEM_SUPPORTED
   if(malloc_fn != NULL)
   {
      if (mem_ptr != NULL)
      {
         png_struct dummy_struct;
         png_structp png_ptr = &dummy_struct;
         png_ptr->mem_ptr=mem_ptr;
         struct_ptr = (*(malloc_fn))(png_ptr, size);
      }
      else
         struct_ptr = (*(malloc_fn))(NULL, size);
      if (struct_ptr != NULL)
         png_memset(struct_ptr, 0, size);
      return (struct_ptr);
   }
#endif /* PNG_USER_MEM_SUPPORTED */

#if defined(__TURBOC__) && !defined(__FLAT__)
   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
   if ((struct_ptr = (png_voidp)halloc(size,1)) != NULL)
# else
   if ((struct_ptr = (png_voidp)malloc(size)) != NULL)
# endif
#endif
   {
      png_memset(struct_ptr, 0, size);
   }

   return (struct_ptr);
}


/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)
{
#ifdef PNG_USER_MEM_SUPPORTED
   png_destroy_struct_2(struct_ptr, (png_free_ptr)NULL, (png_voidp)NULL);
}

/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
    png_voidp mem_ptr)
{
#endif /* PNG_USER_MEM_SUPPORTED */
   if (struct_ptr != NULL)
   {
#ifdef PNG_USER_MEM_SUPPORTED
      if(free_fn != NULL)
      {
         png_struct dummy_struct;
         png_structp png_ptr = &dummy_struct;
         png_ptr->mem_ptr=mem_ptr;
         (*(free_fn))(png_ptr, struct_ptr);
         return;
      }
#endif /* PNG_USER_MEM_SUPPORTED */
#if defined(__TURBOC__) && !defined(__FLAT__)
      farfree(struct_ptr);
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
      hfree(struct_ptr);
# else
      free(struct_ptr);
# endif
#endif
   }
}


/* Allocate memory.  For reasonable files, size should never exceed
   64K.  However, zlib may allocate more then 64K if you don't tell
   it not to.  See zconf.h and png.h for more information.  zlib does
   need to allocate exactly 64K, so whatever you call here must
   have the ability to do that. */

png_voidp PNGAPI
png_malloc(png_structp png_ptr, png_uint_32 size)
{
   png_voidp ret;
   if (png_ptr == NULL || size == 0)
      return ((png_voidp)NULL);

#ifdef PNG_USER_MEM_SUPPORTED
   if(png_ptr->malloc_fn != NULL)
   {
       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
       if (ret == NULL)
          png_error(png_ptr, "Out of Memory!");
       return (ret);
   }
   else
       return (png_malloc_default(png_ptr, size));
}
png_voidp /* PRIVATE */
png_malloc_default(png_structp png_ptr, png_uint_32 size)
{
   png_voidp ret;
#endif /* PNG_USER_MEM_SUPPORTED */

#ifdef PNG_MAX_MALLOC_64K
   if (size > (png_uint_32)65536L)
      png_error(png_ptr, "Cannot Allocate > 64K");
#endif

#if defined(__TURBOC__) && !defined(__FLAT__)
   ret = farmalloc(size);
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
   ret = halloc(size, 1);
# else
   ret = malloc((size_t)size);
# endif
#endif

   if (ret == NULL)
      png_error(png_ptr, "Out of Memory");

   return (ret);
}

/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
   without taking any action. */
void PNGAPI
png_free(png_structp png_ptr, png_voidp ptr)
{
   if (png_ptr == NULL || ptr == NULL)
      return;

#ifdef PNG_USER_MEM_SUPPORTED
   if (png_ptr->free_fn != NULL)
   {
      (*(png_ptr->free_fn))(png_ptr, ptr);
      return;
   }
   else png_free_default(png_ptr, ptr);
}
void /* PRIVATE */
png_free_default(png_structp png_ptr, png_voidp ptr)
{
   if (png_ptr == NULL || ptr == NULL)
      return;

#endif /* PNG_USER_MEM_SUPPORTED */

#if defined(__TURBOC__) && !defined(__FLAT__)
   farfree(ptr);
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
   hfree(ptr);
# else
   free(ptr);
# endif
#endif
}

#endif /* Not Borland DOS special memory handler */

png_voidp /* PRIVATE */
png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
   png_uint_32 length)
{
   png_size_t size;

   size = (png_size_t)length;
   if ((png_uint_32)size != length)
      png_error(png_ptr,"Overflow in png_memcpy_check.");

   return(png_memcpy (s1, s2, size));
}

png_voidp /* PRIVATE */
png_memset_check (png_structp png_ptr, png_voidp s1, int value,
   png_uint_32 length)
{
   png_size_t size;

   size = (png_size_t)length;
   if ((png_uint_32)size != length)
      png_error(png_ptr,"Overflow in png_memset_check.");

   return (png_memset (s1, value, size));

}

#ifdef PNG_USER_MEM_SUPPORTED
/* This function is called when the application wants to use another method
 * of allocating and freeing memory.
 */
void PNGAPI
png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
  malloc_fn, png_free_ptr free_fn)
{
   png_ptr->mem_ptr = mem_ptr;
   png_ptr->malloc_fn = malloc_fn;
   png_ptr->free_fn = free_fn;
}

/* This function returns a pointer to the mem_ptr associated with the user
 * functions.  The application should free any memory associated with this
 * pointer before png_write_destroy and png_read_destroy are called.
 */
png_voidp PNGAPI
png_get_mem_ptr(png_structp png_ptr)
{
   return ((png_voidp)png_ptr->mem_ptr);
}
#endif /* PNG_USER_MEM_SUPPORTED */

--- NEW FILE: pngtrans.c ---

/* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

#define PNG_INTERNAL
#include "png.h"

#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
/* turn on BGR-to-RGB mapping */
void PNGAPI
png_set_bgr(png_structp png_ptr)
{
   png_debug(1, "in png_set_bgr\n");
   png_ptr->transformations |= PNG_BGR;
}
#endif

#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
/* turn on 16 bit byte swapping */
void PNGAPI
png_set_swap(png_structp png_ptr)
{
   png_debug(1, "in png_set_swap\n");
   if (png_ptr->bit_depth == 16)
      png_ptr->transformations |= PNG_SWAP_BYTES;
}
#endif

#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
/* turn on pixel packing */
void PNGAPI
png_set_packing(png_structp png_ptr)
{
   png_debug(1, "in png_set_packing\n");
   if (png_ptr->bit_depth < 8)
   {
      png_ptr->transformations |= PNG_PACK;
      png_ptr->usr_bit_depth = 8;
   }
}
#endif

#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
/* turn on packed pixel swapping */
void PNGAPI
png_set_packswap(png_structp png_ptr)
{
   png_debug(1, "in png_set_packswap\n");
   if (png_ptr->bit_depth < 8)
      png_ptr->transformations |= PNG_PACKSWAP;
}
#endif

#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
void PNGAPI
png_set_shift(png_structp png_ptr, png_color_8p true_bits)
{
   png_debug(1, "in png_set_shift\n");
   png_ptr->transformations |= PNG_SHIFT;
   png_ptr->shift = *true_bits;
}
#endif

#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
    defined(PNG_WRITE_INTERLACING_SUPPORTED)
int PNGAPI
png_set_interlace_handling(png_structp png_ptr)
{
   png_debug(1, "in png_set_interlace handling\n");
   if (png_ptr->interlaced)
   {
      png_ptr->transformations |= PNG_INTERLACE;
      return (7);
   }

   return (1);
}
#endif

#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
/* Add a filler byte on read, or remove a filler or alpha byte on write.
 * The filler type has changed in v0.95 to allow future 2-byte fillers
 * for 48-bit input data, as well as to avoid problems with some compilers
 * that don't like bytes as parameters.
 */
void PNGAPI
png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
{
   png_debug(1, "in png_set_filler\n");
   png_ptr->transformations |= PNG_FILLER;
   png_ptr->filler = (png_byte)filler;
   if (filler_loc == PNG_FILLER_AFTER)
      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
   else
      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;

   /* This should probably go in the "do_filler" routine.
    * I attempted to do that in libpng-1.0.1a but that caused problems
    * so I restored it in libpng-1.0.2a
   */

   if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
   {
      png_ptr->usr_channels = 4;
   }

   /* Also I added this in libpng-1.0.2a (what happens when we expand
    * a less-than-8-bit grayscale to GA? */

   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
   {
      png_ptr->usr_channels = 2;
   }
}
#endif

#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
void PNGAPI
png_set_swap_alpha(png_structp png_ptr)
{
   png_debug(1, "in png_set_swap_alpha\n");
   png_ptr->transformations |= PNG_SWAP_ALPHA;
}
#endif

#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
void PNGAPI
png_set_invert_alpha(png_structp png_ptr)
{
   png_debug(1, "in png_set_invert_alpha\n");
   png_ptr->transformations |= PNG_INVERT_ALPHA;
}
#endif

#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
void PNGAPI
png_set_invert_mono(png_structp png_ptr)
{
   png_debug(1, "in png_set_invert_mono\n");
   png_ptr->transformations |= PNG_INVERT_MONO;
}

/* invert monochrome grayscale data */
void /* PRIVATE */
png_do_invert(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_invert\n");
   if (row_info->bit_depth == 1 &&
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       row_info->color_type == PNG_COLOR_TYPE_GRAY)
   {
      png_bytep rp = row;
      png_uint_32 i;
      png_uint_32 istop = row_info->rowbytes;

      for (i = 0; i < istop; i++)
      {
         *rp = (png_byte)(~(*rp));
         rp++;
      }
   }
}
#endif

#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
/* swaps byte order on 16 bit depth images */
void /* PRIVATE */
png_do_swap(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_swap\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       row_info->bit_depth == 16)
   {
      png_bytep rp = row;
      png_uint_32 i;
      png_uint_32 istop= row_info->width * row_info->channels;

      for (i = 0; i < istop; i++, rp += 2)
      {
         png_byte t = *rp;
         *rp = *(rp + 1);
         *(rp + 1) = t;
      }
   }
}
#endif

#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
static png_byte onebppswaptable[256] = {
   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
};

static png_byte twobppswaptable[256] = {
   0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
   0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
   0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
   0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
   0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
   0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
   0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
   0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
   0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
   0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
   0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
   0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
   0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
   0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
   0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
   0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
   0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
   0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
   0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
   0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
   0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
   0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
   0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
   0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
   0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
   0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
   0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
   0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
   0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
   0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
   0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
   0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
};

static png_byte fourbppswaptable[256] = {
   0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
   0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
   0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
   0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
   0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
   0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
   0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
   0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
   0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
   0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
   0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
   0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
   0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
   0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
   0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
   0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
   0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
   0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
   0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
   0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
   0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
   0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
   0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
   0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
   0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
   0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
   0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
   0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
   0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
   0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
   0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
   0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
};

/* swaps pixel packing order within bytes */
void /* PRIVATE */
png_do_packswap(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_packswap\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       row_info->bit_depth < 8)
   {
      png_bytep rp, end, table;

      end = row + row_info->rowbytes;

      if (row_info->bit_depth == 1)
         table = onebppswaptable;
      else if (row_info->bit_depth == 2)
         table = twobppswaptable;
      else if (row_info->bit_depth == 4)
         table = fourbppswaptable;
      else
         return;

      for (rp = row; rp < end; rp++)
         *rp = table[*rp];
   }
}
#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */

#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
/* remove filler or alpha byte(s) */
void /* PRIVATE */
png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
{
   png_debug(1, "in png_do_strip_filler\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
/*
      if (row_info->color_type == PNG_COLOR_TYPE_RGB ||
          row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
*/
      png_bytep sp=row;
      png_bytep dp=row;
      png_uint_32 row_width=row_info->width;
      png_uint_32 i;

      if (row_info->channels == 4)
      {
         if (row_info->bit_depth == 8)
         {
            /* This converts from RGBX or RGBA to RGB */
            if (flags & PNG_FLAG_FILLER_AFTER)
            {
               dp+=3; sp+=4;
               for (i = 1; i < row_width; i++)
               {
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  sp++;
               }
            }
            /* This converts from XRGB or ARGB to RGB */
            else
            {
               for (i = 0; i < row_width; i++)
               {
                  sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
               }
            }
            row_info->pixel_depth = 24;
            row_info->rowbytes = row_width * 3;
         }
         else /* if (row_info->bit_depth == 16) */
         {
            if (flags & PNG_FLAG_FILLER_AFTER)
            {
               /* This converts from RRGGBBXX or RRGGBBAA to RRGGBB */
               sp += 8; dp += 6;
               for (i = 1; i < row_width; i++)
               {
                  /* This could be (although png_memcpy is probably slower):
                  png_memcpy(dp, sp, 6);
                  sp += 8;
                  dp += 6;
                  */

                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  sp += 2;
               }
            }
            else
            {
               /* This converts from XXRRGGBB or AARRGGBB to RRGGBB */
               for (i = 0; i < row_width; i++)
               {
                  /* This could be (although png_memcpy is probably slower):
                  png_memcpy(dp, sp, 6);
                  sp += 8;
                  dp += 6;
                  */

                  sp+=2;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
               }
            }
            row_info->pixel_depth = 48;
            row_info->rowbytes = row_width * 6;
         }
         row_info->channels = 3;
         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
      }
/*
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY ||
               row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
*/
      else if (row_info->channels == 2)
      {
         if (row_info->bit_depth == 8)
         {
            /* This converts from GX or GA to G */
            if (flags & PNG_FLAG_FILLER_AFTER)
            {
               for (i = 0; i < row_width; i++)
               {
                  *dp++ = *sp++;
                  sp++;
               }
            }
            /* This converts from XG or AG to G */
            else
            {
               for (i = 0; i < row_width; i++)
               {
                  sp++;
                  *dp++ = *sp++;
               }
            }
            row_info->pixel_depth = 8;
            row_info->rowbytes = row_width;
         }
         else /* if (row_info->bit_depth == 16) */
         {
            if (flags & PNG_FLAG_FILLER_AFTER)
            {
               /* This converts from GGXX or GGAA to GG */
               sp += 4; dp += 2;
               for (i = 1; i < row_width; i++)
               {
                  *dp++ = *sp++;
                  *dp++ = *sp++;
                  sp += 2;
               }
            }
            else
            {
               /* This converts from XXGG or AAGG to GG */
               for (i = 0; i < row_width; i++)
               {
                  sp += 2;
                  *dp++ = *sp++;
                  *dp++ = *sp++;
               }
            }
            row_info->pixel_depth = 16;
            row_info->rowbytes = row_width * 2;
         }
         row_info->channels = 1;
         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
      }
   }
}
#endif

#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
/* swaps red and blue bytes within a pixel */
void /* PRIVATE */
png_do_bgr(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_bgr\n");
   if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
       (row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      png_uint_32 row_width = row_info->width;
      if (row_info->bit_depth == 8)
      {
         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
         {
            png_bytep rp;
            png_uint_32 i;

            for (i = 0, rp = row; i < row_width; i++, rp += 3)
            {
               png_byte save = *rp;
               *rp = *(rp + 2);
               *(rp + 2) = save;
            }
         }
         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
         {
            png_bytep rp;
            png_uint_32 i;

            for (i = 0, rp = row; i < row_width; i++, rp += 4)
            {
               png_byte save = *rp;
               *rp = *(rp + 2);
               *(rp + 2) = save;
            }
         }
      }
      else if (row_info->bit_depth == 16)
      {
         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
         {
            png_bytep rp;
            png_uint_32 i;

            for (i = 0, rp = row; i < row_width; i++, rp += 6)
            {
               png_byte save = *rp;
               *rp = *(rp + 4);
               *(rp + 4) = save;
               save = *(rp + 1);
               *(rp + 1) = *(rp + 5);
               *(rp + 5) = save;
            }
         }
         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
         {
            png_bytep rp;
            png_uint_32 i;

            for (i = 0, rp = row; i < row_width; i++, rp += 8)
            {
               png_byte save = *rp;
               *rp = *(rp + 4);
               *(rp + 4) = save;
               save = *(rp + 1);
               *(rp + 1) = *(rp + 5);
               *(rp + 5) = save;
            }
         }
      }
   }
}
#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_LEGACY_SUPPORTED)
void PNGAPI
png_set_user_transform_info(png_structp png_ptr, png_voidp
   user_transform_ptr, int user_transform_depth, int user_transform_channels)
{
   png_debug(1, "in png_set_user_transform_info\n");
#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   png_ptr->user_transform_ptr = user_transform_ptr;
   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
#else
   if(user_transform_ptr || user_transform_depth || user_transform_channels)
      png_warning(png_ptr,
        "This version of libpng does not support user transform info");
#endif
}
#endif

/* This function returns a pointer to the user_transform_ptr associated with
 * the user transform functions.  The application should free any memory
 * associated with this pointer before png_write_destroy and png_read_destroy
 * are called.
 */
png_voidp PNGAPI
png_get_user_transform_ptr(png_structp png_ptr)
{
#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   return ((png_voidp)png_ptr->user_transform_ptr);
#else
   if(png_ptr)
     return (NULL);
   return (NULL);
#endif
}


--- NEW FILE: README ---
README for libpng 1.0.12 - June 8, 2001 (shared library 2.1)
See the note about version numbers near the top of png.h

See INSTALL for instructions on how to install libpng.

Libpng comes in two distribution formats.  Get libpng-*.tar.gz if you
want UNIX-style line endings in the text files, or lpng*.zip if you want
DOS-style line endings.

Version 0.89 was the first official release of libpng.  Don't let the
fact that it's the first release fool you.  The libpng library has been in
extensive use and testing since mid-1995.  By late 1997 it had
finally gotten to the stage where there hadn't been significant
changes to the API in some time, and people have a bad feeling about
libraries with versions < 1.0.  Version 1.0.0 was released in
March 1998.

****
Note that some of the changes to the png_info structure render this
version of the library binary incompatible with libpng-0.89 or
earlier versions if you are using a shared library.  The type of the
"filler" parameter for png_set_filler() has changed from png_byte to
png_uint_32, which will affect shared-library applications that use
this function.

To avoid problems with changes to the internals of png_info_struct,
new APIs have been made available in 0.95 to avoid direct application
access to info_ptr.  These functions are the png_set_<chunk> and
png_get_<chunk> functions.  These functions should be used when
accessing/storing the info_struct data, rather than manipulating it
directly, to avoid such problems in the future.

It is important to note that the APIs do not make current programs
that access the info struct directly incompatible with the new
library.  However, it is strongly suggested that new programs use
the new APIs (as shown in example.c and pngtest.c), and older programs
be converted to the new format, to facilitate upgrades in the future.
****

Additions since 0.90 include the ability to compile libpng as a
Windows DLL, and new APIs for accessing data in the info struct.
Experimental functions include the ability to set weighting and cost
factors for row filter selection, direct reads of integers from buffers
on big-endian processors that support misaligned data access, faster
methods of doing alpha composition, and more accurate 16->8 bit color
conversion.

The additions since 0.89 include the ability to read from a PNG stream
which has had some (or all) of the signature bytes read by the calling
application.  This also allows the reading of embedded PNG streams that
do not have the PNG file signature.  As well, it is now possible to set
the library action on the detection of chunk CRC errors.  It is possible
to set different actions based on whether the CRC error occurred in a
critical or an ancillary chunk.

The changes made to the library, and bugs fixed are based on discussions
on the PNG implementation mailing list <png-implement at ccrc.wustl.edu>
and not on material submitted privately to Guy, Andreas, or Glenn.  They will
forward any good suggestions to the list.

For a detailed description on using libpng, read libpng.txt.  For
examples of libpng in a program, see example.c and pngtest.c.  For usage
information and restrictions (what little they are) on libpng, see
png.h.  For a description on using zlib (the compression library used by
libpng) and zlib's restrictions, see zlib.h

I have included a general makefile, as well as several machine and
compiler specific ones, but you may have to modify one for your own needs.

You should use zlib 1.0.4 or later to run this, but it MAY work with
versions as old as zlib 0.95.  Even so, there are bugs in older zlib
versions which can cause the output of invalid compression streams for
some images.  You will definitely need zlib 1.0.4 or later if you are
taking advantage of the MS-DOS "far" structure allocation for the small
and medium memory models.  You should also note that zlib is a
compression library that is useful for more things than just PNG files.
You can use zlib as a drop-in replacement for fread() and fwrite() if
you are so inclined.

zlib should be available at the same place that libpng is.
If not, it should be at ftp.uu.net in /graphics/png
Eventually, it will be at ftp.uu.net in /pub/archiving/zip/zlib

You may also want a copy of the PNG specification.  It is available
as an RFC and a W3C Recommendation.  Failing
these resources you can try ftp.uu.net in the /graphics/png directory.

This code is currently being archived at ftp.uu.net in the
/graphics/png directory, and on CompuServe, Lib 20 (PNG SUPPORT)
at GO GRAPHSUP.  If you can't find it in any of those places,
e-mail me, and I'll help you find it.

If you have any code changes, requests, problems, etc., please e-mail
them to me.  Also, I'd appreciate any make files or project files,
and any modifications you needed to make to get libpng to compile,
along with a #define variable to tell what compiler/system you are on.
If you needed to add transformations to libpng, or wish libpng would
provide the image in a different way, drop me a note (and code, if
possible), so I can consider supporting the transformation.
Finally, if you get any warning messages when compiling libpng
(note: not zlib), and they are easy to fix, I'd appreciate the
fix.  Please mention "libpng" somewhere in the subject line.  Thanks.

This release was created and will be supported by myself (of course
based in a large way on Guy's and Andreas' earlier work), and the PNG group.

randeg at alum.rpi.edu
png-implement at ccrc.wustl.edu

You can't reach Guy, the original libpng author, at the addresses
given in previous versions of this document.  He and Andreas will read mail
addressed to the png-implement list, however.

Please do not send general questions about PNG.  Send them to
the address in the specification (png-group at w3.org).  At the same
time, please do not send libpng questions to that address, send them to me
or to png-implement at ccrc.wustl.edu.  I'll
get them in the end anyway.  If you have a question about something
in the PNG specification that is related to using libpng, send it
to me.  Send me any questions that start with "I was using libpng,
and ...".  If in doubt, send questions to me.  I'll bounce them
to others, if necessary.

Please do not send suggestions on how to change PNG.  We have
been discussing PNG for three years now, and it is official and
finished.  If you have suggestions for libpng, however, I'll
gladly listen.  Even if your suggestion is not used for version
1.0, it may be used later.

Files in this distribution:

      ANNOUNCE      =>  Announcement of this version, with recent changes
      CHANGES       =>  Description of changes between libpng versions
      KNOWNBUG      =>  List of known bugs and deficiencies
      LICENSE       =>  License to use and redistribute libpng
      README        =>  This file
      TODO          =>  Things not implemented in the current library
      Y2KINFO       =>  Statement of Y2K compliance
      example.c     =>  Example code for using libpng functions
      libpng.3      =>  manual page for libpng (includes libpng.txt)
      libpng.txt    =>  Description of libpng and its functions
      libpngpf.3    =>  manual page for libpng's private functions
      png.5         =>  manual page for the PNG format
      png.c         =>  Basic interface functions common to library
      png.h         =>  Library function and interface declarations
      pngconf.h     =>  System specific library configuration
      pngasmrd.h    =>  Header file for assembler-coded functions
      pngerror.c    =>  Error/warning message I/O functions
      pngget.c      =>  Functions for retrieving info from struct
      pngmem.c      =>  Memory handling functions
      pngbar.png    =>  PNG logo, 88x31
      pngnow.png    =>  PNG logo, 98x31
      pngpread.c    =>  Progressive reading functions
      pngread.c     =>  Read data/helper high-level functions
      pngrio.c      =>  Lowest-level data read I/O functions
      pngrtran.c    =>  Read data transformation functions
      pngrutil.c    =>  Read data utility functions
      pngset.c      =>  Functions for storing data into the info_struct
      pngtest.c     =>  Library test program
      pngtest.png   =>  Library test sample image
      pngtrans.c    =>  Common data transformation functions
      pngwio.c      =>  Lowest-level write I/O functions
      pngwrite.c    =>  High-level write functions
      pngwtran.c    =>  Write data transformations
      pngwutil.c    =>  Write utility functions
      contrib       =>  Contributions
       gregbook         =>  source code for PNG reading and writing, from
                            Greg Roelofs' "PNG: The Definitive Guide",
                            O'Reilly, 1999
       msvctest     =>  Builds and runs pngtest using a MSVC workspace
       pngminus     =>  Simple pnm2png and png2pnm programs
       pngsuite     =>  Test images
       visupng      =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for building DLL
       beos             =>  Contains a Beos workspace for building libpng
       borland          =>  Contains a Borland workspace for building libpng
                            and zlib
       msvc             =>  Contains a Microsoft Visual C++ (MSVC) workspace
                            for building libpng and zlib
       netware.txt      =>  Contains instructions for downloading a set of
                            project files for building libpng and zlib on
                            Netware.
       wince.txt        =>  Contains instructions for downloading a Microsoft
                            Visual C++ (Windows CD Toolkit) workspace for
                            building libpng and zlib on WindowsCE
      scripts       =>  Directory containing scripts for building libpng:
       descrip.mms      =>  VMS makefile for MMS or MMK
       makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
       makefile.linux   =>  Linux/ELF makefile
                            (gcc, creates libpng.so.2.1.0.12)
       makefile.gcmmx   =>  Linux/ELF makefile (gcc, creates
                            libpng.so.2.1.0.12, uses assembler code
                            tuned for Intel MMX platform)
       makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
       makefile.knr     =>  Archaic UNIX Makefile that converts files with
                            ansi2knr (Requires ansi2knr.c from
                            ftp://ftp.cs.wisc.edu/ghost)
       makefile.aix     =>  AIX makefile
       makefile.cygwin  =>  Cygwin/gcc makefile
       makefile.dec     =>  DEC Alpha UNIX makefile
       makefile.hpgcc   =>  HPUX makefile using gcc
       makefile.hpux    =>  HPUX (10.20 and 11.00) makefile
       makefile.ibmc    =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
       makefile.intel   =>  Intel C/C++ version 4.0 and later
       libpng.icc       =>  Project file, IBM VisualAge/C++ 4.0 or later
       makefile.macosx  =>  MACOS X Makefile
       makefile.netbsd  =>  NetBSD/cc makefile, uses PNGGCCRD
       makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
       makefile.sggcc   =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.12)
       makefile.sunos   =>  Sun makefile
       makefile.solaris =>  Solaris 2.X makefile
                            (gcc, creates libpng.so.2.1.0.12)
       makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
       makefile.mips    =>  MIPS makefile
       makefile.acorn   =>  Acorn makefile
       makefile.amiga   =>  Amiga makefile
       smakefile.ppc    =>  AMIGA smakefile for SAS C V6.58/7.00 PPC
                            compiler (Requires SCOPTIONS, copied from
                            scripts/SCOPTIONS.ppc)
       makefile.atari   =>  Atari makefile
       makefile.beos    =>  BEOS makefile for X86
       makefile.bor     =>  Borland makefile (uses bcc)
       makefile.bc32    =>  32-bit Borland C++ (all modules compiled in C mode)
       makefile.bd32    =>  To make a png32bd.dll with Borland C++ 4.5
       makefile.tc3     =>  Turbo C 3.0 makefile
       makefile.dj2     =>  DJGPP 2 makefile
       makefile.msc     =>  Microsoft C makefile
       makefile.vcawin32 => makefile for Microsoft Visual C++ 5.0 and
                            later (uses assembler code tuned for Intel MMX
                            platform)
       makefile.vcwin32 =>  makefile for Microsoft Visual C++ 4.0 and
                            later (does not use assembler code)
       makefile.os2     =>  OS/2 Makefile (gcc and emx, requires pngos2.def)
       pngos2.def       =>  OS/2 module definition file used by makefile.os2
       makefile.watcom  =>  Watcom 10a+ Makefile, 32-bit flat memory model
       makevms.com      =>  VMS build script
       pngdef.pas       =>  Defines for a png32bd.dll with Borland C++ 4.5
       SCOPTIONS.ppc    =>  Used with smakefile.ppc

Good luck, and happy coding.

-Glenn Randers-Pehrson
 Internet: randeg at alum.rpi.edu

-Andreas Eric Dilger
 Internet: adilger at enel.ucalgary.ca
 Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/

-Guy Eric Schalnat
 (formerly of Group 42, Inc)
 Internet: gschal at infinet.com

--- NEW FILE: ANNOUNCE ---

Libpng 1.0.12 - June 8, 2001

This is a public release of libpng, intended for use in production codes.

Changes since the last public release (1.0.11):

  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
  Bumped DLLNUM to 2.
  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
  Eliminated the png_error about apps using png_read|write_init().  Instead,
    libpng will reallocate the png_struct and info_struct if they are too small.
    This achieves future binary compatibility for old applications written for
    libpng-0.88 and earlier.  Expanded the warnings about incompatible library
    and application.
  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
  Check for missing profile length field in iCCP chunk and free the chunk_data
     in case of truncated iCCP chunk.
  Added netware project, distributed in a separate zip file.
  Began distributing wince project in a separate zip file.
  Updated contrib/gregbook

Send comments/corrections/commendations to
png-implement at ccrc.wustl.edu or to randeg at alum.rpi.edu

Glenn R-P

--- NEW FILE: pngwutil.c ---

/* pngwutil.c - utilities to write a PNG file
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

#define PNG_INTERNAL
#include "png.h"
#ifdef PNG_WRITE_SUPPORTED

/* Place a 32-bit number into a buffer in PNG byte order.  We work
 * with unsigned numbers for convenience, although one supported
 * ancillary chunk uses signed (two's complement) numbers.
 */
void /* PRIVATE */
[...2607 lines suppressed...]

      tptr = png_ptr->prev_row;
      png_ptr->prev_row = png_ptr->row_buf;
      png_ptr->row_buf = tptr;
   }

   /* finish row - updates counters and flushes zlib if last row */
   png_write_finish_row(png_ptr);

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
   png_ptr->flush_rows++;

   if (png_ptr->flush_dist > 0 &&
       png_ptr->flush_rows >= png_ptr->flush_dist)
   {
      png_write_flush(png_ptr);
   }
#endif
}
#endif /* PNG_WRITE_SUPPORTED */

--- NEW FILE: pngwio.c ---

/* pngwio.c - functions for data output
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * This file provides a location for all output.  Users who need
 * special handling are expected to write functions that have the same
 * arguments as these and perform similar functions, but that possibly
 * use different output methods.  Note that you shouldn't change these
 * functions, but rather write replacement functions and then change
 * them at run time with png_set_write_fn(...).
 */

#define PNG_INTERNAL
#include "png.h"
#ifdef PNG_WRITE_SUPPORTED

/* Write the data to whatever output you are using.  The default routine
   writes to a file pointer.  Note that this routine sometimes gets called
   with very small lengths, so you should implement some kind of simple
   buffering if you are using unbuffered writes.  This should never be asked
   to write more than 64K on a 16 bit machine.  */

void /* PRIVATE */
png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   if (png_ptr->write_data_fn != NULL )
      (*(png_ptr->write_data_fn))(png_ptr, data, length);
   else
      png_error(png_ptr, "Call to NULL write function");
}

#if !defined(PNG_NO_STDIO)
/* This is the function that does the actual writing of data.  If you are
   not writing to a standard C stream, you should create a replacement
   write_data function and use it at run time with png_set_write_fn(), rather
   than changing the library. */
#ifndef USE_FAR_KEYWORD
static void /* PRIVATE */
png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   png_uint_32 check;

#if defined(_WIN32_WCE)
   if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
      check = 0;
#else
   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
#endif
   if (check != length)
      png_error(png_ptr, "Write Error");
}
#else
/* this is the model-independent version. Since the standard I/O library
   can't handle far buffers in the medium and small models, we have to copy
   the data.
*/

#define NEAR_BUF_SIZE 1024
#define MIN(a,b) (a <= b ? a : b)

static void /* PRIVATE */
png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   png_uint_32 check;
   png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
   png_FILE_p io_ptr;

   /* Check if data really is near. If so, use usual code. */
   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
   if ((png_bytep)near_data == data)
   {
#if defined(_WIN32_WCE)
      if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
         check = 0;
#else
      check = fwrite(near_data, 1, length, io_ptr);
#endif
   }
   else
   {
      png_byte buf[NEAR_BUF_SIZE];
      png_size_t written, remaining, err;
      check = 0;
      remaining = length;
      do
      {
         written = MIN(NEAR_BUF_SIZE, remaining);
         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
#if defined(_WIN32_WCE)
         if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
            err = 0;
#else
         err = fwrite(buf, 1, written, io_ptr);
#endif
         if (err != written)
            break;
         else
            check += err;
         data += written;
         remaining -= written;
      }
      while (remaining != 0);
   }
   if (check != length)
      png_error(png_ptr, "Write Error");
}

#endif
#endif

/* This function is called to output any data pending writing (normally
   to disk).  After png_flush is called, there should be no data pending
   writing in any buffers. */
#if defined(PNG_WRITE_FLUSH_SUPPORTED)
void /* PRIVATE */
png_flush(png_structp png_ptr)
{
   if (png_ptr->output_flush_fn != NULL)
      (*(png_ptr->output_flush_fn))(png_ptr);
}

#if !defined(PNG_NO_STDIO)
static void /* PRIVATE */
png_default_flush(png_structp png_ptr)
{
#if !defined(_WIN32_WCE)
   png_FILE_p io_ptr;
   io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
   if (io_ptr != NULL)
      fflush(io_ptr);
#endif
}
#endif
#endif

/* This function allows the application to supply new output functions for
   libpng if standard C streams aren't being used.

   This function takes as its arguments:
   png_ptr       - pointer to a png output data structure
   io_ptr        - pointer to user supplied structure containing info about
                   the output functions.  May be NULL.
   write_data_fn - pointer to a new output function that takes as its
                   arguments a pointer to a png_struct, a pointer to
                   data to be written, and a 32-bit unsigned int that is
                   the number of bytes to be written.  The new write
                   function should call png_error(png_ptr, "Error msg")
                   to exit and output any fatal error messages.
   flush_data_fn - pointer to a new flush function that takes as its
                   arguments a pointer to a png_struct.  After a call to
                   the flush function, there should be no data in any buffers
                   or pending transmission.  If the output method doesn't do
                   any buffering of ouput, a function prototype must still be
                   supplied although it doesn't have to do anything.  If
                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
                   time, output_flush_fn will be ignored, although it must be
                   supplied for compatibility. */
void PNGAPI
png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
   png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
{
   png_ptr->io_ptr = io_ptr;

#if !defined(PNG_NO_STDIO)
   if (write_data_fn != NULL)
      png_ptr->write_data_fn = write_data_fn;
   else
      png_ptr->write_data_fn = png_default_write_data;
#else
   png_ptr->write_data_fn = write_data_fn;
#endif

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
#if !defined(PNG_NO_STDIO)
   if (output_flush_fn != NULL)
      png_ptr->output_flush_fn = output_flush_fn;
   else
      png_ptr->output_flush_fn = png_default_flush;
#else
   png_ptr->output_flush_fn = output_flush_fn;
#endif
#endif /* PNG_WRITE_FLUSH_SUPPORTED */

   /* It is an error to read while writing a png file */
   if (png_ptr->read_data_fn != NULL)
   {
      png_ptr->read_data_fn = NULL;
      png_warning(png_ptr,
         "Attempted to set both read_data_fn and write_data_fn in");
      png_warning(png_ptr,
         "the same structure.  Resetting read_data_fn to NULL.");
   }
}

#if defined(USE_FAR_KEYWORD)
#if defined(_MSC_VER)
void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
{
   void *near_ptr;
   void FAR *far_ptr;
   FP_OFF(near_ptr) = FP_OFF(ptr);
   far_ptr = (void FAR *)near_ptr;
   if(check != 0)
      if(FP_SEG(ptr) != FP_SEG(far_ptr))
         png_error(png_ptr,"segment lost in conversion");
   return(near_ptr);
}
#  else
void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
{
   void *near_ptr;
   void FAR *far_ptr;
   near_ptr = (void FAR *)ptr;
   far_ptr = (void FAR *)near_ptr;
   if(check != 0)
      if(far_ptr != ptr)
         png_error(png_ptr,"segment lost in conversion");
   return(near_ptr);
}
#   endif
#   endif
#endif /* PNG_WRITE_SUPPORTED */

--- NEW FILE: pngset.c ---

/* pngset.c - storage of image information into info struct
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 *
 * The functions here are used during reads to store data from the file
 * into the info struct, and during writes to store application data
 * into the info struct for writing into the file.  This abstracts the
 * info struct and allows us to change the structure in the future.
 */

#define PNG_INTERNAL
#include "png.h"

#if defined(PNG_bKGD_SUPPORTED)
void PNGAPI
png_set_bKGD(png_structp png_ptr, png_infop info_ptr, png_color_16p background)
{
   png_debug1(1, "in %s storage function\n", "bKGD");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   png_memcpy(&(info_ptr->background), background, sizeof(png_color_16));
   info_ptr->valid |= PNG_INFO_bKGD;
}
#endif

#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
void PNGAPI
png_set_cHRM(png_structp png_ptr, png_infop info_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)
{
   png_debug1(1, "in %s storage function\n", "cHRM");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->x_white = (float)white_x;
   info_ptr->y_white = (float)white_y;
   info_ptr->x_red   = (float)red_x;
   info_ptr->y_red   = (float)red_y;
   info_ptr->x_green = (float)green_x;
   info_ptr->y_green = (float)green_y;
   info_ptr->x_blue  = (float)blue_x;
   info_ptr->y_blue  = (float)blue_y;
#ifdef PNG_FIXED_POINT_SUPPORTED
   info_ptr->int_x_white = (png_fixed_point)(white_x*100000.+0.5);
   info_ptr->int_y_white = (png_fixed_point)(white_y*100000.+0.5);
   info_ptr->int_x_red   = (png_fixed_point)(red_x*100000.+0.5);
   info_ptr->int_y_red   = (png_fixed_point)(red_y*100000.+0.5);
   info_ptr->int_x_green = (png_fixed_point)(green_x*100000.+0.5);
   info_ptr->int_y_green = (png_fixed_point)(green_y*100000.+0.5);
   info_ptr->int_x_blue  = (png_fixed_point)(blue_x*100000.+0.5);
   info_ptr->int_y_blue  = (png_fixed_point)(blue_y*100000.+0.5);
#endif
   info_ptr->valid |= PNG_INFO_cHRM;
}
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
void PNGAPI
png_set_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
   png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
   png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
   png_fixed_point blue_x, png_fixed_point blue_y)
{
   png_debug1(1, "in %s storage function\n", "cHRM");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->int_x_white = white_x;
   info_ptr->int_y_white = white_y;
   info_ptr->int_x_red   = red_x;
   info_ptr->int_y_red   = red_y;
   info_ptr->int_x_green = green_x;
   info_ptr->int_y_green = green_y;
   info_ptr->int_x_blue  = blue_x;
   info_ptr->int_y_blue  = blue_y;
#ifdef PNG_FLOATING_POINT_SUPPORTED
   info_ptr->x_white = (float)(white_x/100000.);
   info_ptr->y_white = (float)(white_y/100000.);
   info_ptr->x_red   = (float)(red_x/100000.);
   info_ptr->y_red   = (float)(red_y/100000.);
   info_ptr->x_green = (float)(green_x/100000.);
   info_ptr->y_green = (float)(green_y/100000.);
   info_ptr->x_blue  = (float)(blue_x/100000.);
   info_ptr->y_blue  = (float)(blue_y/100000.);
#endif
   info_ptr->valid |= PNG_INFO_cHRM;
}
#endif
#endif

#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
void PNGAPI
png_set_gAMA(png_structp png_ptr, png_infop info_ptr, double file_gamma)
{
   png_debug1(1, "in %s storage function\n", "gAMA");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->gamma = (float)file_gamma;
#ifdef PNG_FIXED_POINT_SUPPORTED
   info_ptr->int_gamma = (int)(file_gamma*100000.+.5);
#endif
   info_ptr->valid |= PNG_INFO_gAMA;
   if(file_gamma == 0.0)
      png_warning(png_ptr, "Setting gamma=0");
}
#endif
void PNGAPI
png_set_gAMA_fixed(png_structp png_ptr, png_infop info_ptr, png_fixed_point
   int_gamma)
{
   png_debug1(1, "in %s storage function\n", "gAMA");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

#ifdef PNG_FLOATING_POINT_SUPPORTED
   info_ptr->gamma = (float)(int_gamma/100000.);
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
   info_ptr->int_gamma = int_gamma;
#endif
   info_ptr->valid |= PNG_INFO_gAMA;
   if(int_gamma == 0)
      png_warning(png_ptr, "Setting gamma=0");
}
#endif

#if defined(PNG_hIST_SUPPORTED)
void PNGAPI
png_set_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p hist)
{
   int	i;

   png_debug1(1, "in %s storage function\n", "hIST");
   if (png_ptr == NULL || info_ptr == NULL)
      return;
   if (info_ptr->num_palette == 0)
   {
       png_warning(png_ptr,
          "Palette size 0, hIST allocation skipped.");
       return;
   }

#ifdef PNG_FREE_ME_SUPPORTED
   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
#endif
   png_ptr->hist = (png_uint_16p)png_malloc(png_ptr,
      (png_uint_32)(info_ptr->num_palette * sizeof (png_uint_16)));

   for (i = 0; i < info_ptr->num_palette; i++)
       png_ptr->hist[i] = hist[i];
   info_ptr->hist = png_ptr->hist;
   info_ptr->valid |= PNG_INFO_hIST;

#ifdef PNG_FREE_ME_SUPPORTED
   info_ptr->free_me |= PNG_FREE_HIST;
#else
   png_ptr->flags |= PNG_FLAG_FREE_HIST;
#endif
}
#endif

void PNGAPI
png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
   png_uint_32 width, png_uint_32 height, int bit_depth,
   int color_type, int interlace_type, int compression_type,
   int filter_type)
{
   int rowbytes_per_pixel;
   png_debug1(1, "in %s storage function\n", "IHDR");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   /* check for width and height valid values */
   if (width == 0 || height == 0)
      png_error(png_ptr, "Image width or height is zero in IHDR");
   if (width > PNG_MAX_UINT || height > PNG_MAX_UINT)
      png_error(png_ptr, "Invalid image size in IHDR");

   /* check other values */
   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
      bit_depth != 8 && bit_depth != 16)
      png_error(png_ptr, "Invalid bit depth in IHDR");

   if (color_type < 0 || color_type == 1 ||
      color_type == 5 || color_type > 6)
      png_error(png_ptr, "Invalid color type in IHDR");

   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
       ((color_type == PNG_COLOR_TYPE_RGB ||
         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
      png_error(png_ptr, "Invalid color type/bit depth combination in IHDR");

   if (interlace_type >= PNG_INTERLACE_LAST)
      png_error(png_ptr, "Unknown interlace method in IHDR");

   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
      png_error(png_ptr, "Unknown compression method in IHDR");

#if defined(PNG_MNG_FEATURES_SUPPORTED)
   /* Accept filter_method 64 (intrapixel differencing) only if
    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
    * 2. Libpng did not read a PNG signature (this filter_method is only
    *    used in PNG datastreams that are embedded in MNG datastreams) and
    * 3. The application called png_permit_mng_features with a mask that
    *    included PNG_FLAG_MNG_FILTER_64 and
    * 4. The filter_method is 64 and
    * 5. The color_type is RGB or RGBA
    */
   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&png_ptr->mng_features_permitted)
      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream\n");
   if(filter_type != PNG_FILTER_TYPE_BASE)
   {
     if(!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
        (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
        ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
        (color_type == PNG_COLOR_TYPE_RGB || 
         color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
        png_error(png_ptr, "Unknown filter method in IHDR");
     if(png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)
        png_warning(png_ptr, "Invalid filter method in IHDR");
   }
#else
   if(filter_type != PNG_FILTER_TYPE_BASE)
      png_error(png_ptr, "Unknown filter method in IHDR");
#endif

   info_ptr->width = width;
   info_ptr->height = height;
   info_ptr->bit_depth = (png_byte)bit_depth;
   info_ptr->color_type =(png_byte) color_type;
   info_ptr->compression_type = (png_byte)compression_type;
   info_ptr->filter_type = (png_byte)filter_type;
   info_ptr->interlace_type = (png_byte)interlace_type;
   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;
   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
      info_ptr->channels = 3;
   else
      info_ptr->channels = 1;
   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
      info_ptr->channels++;
   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);

   /* check for overflow */
   rowbytes_per_pixel = (info_ptr->pixel_depth + 7) >> 3;
   if (( width > PNG_MAX_UINT/rowbytes_per_pixel))
   {
      png_warning(png_ptr,
         "Width too large to process image data; rowbytes will overflow.");
      info_ptr->rowbytes = (png_size_t)0;
   }
   else
      info_ptr->rowbytes = (info_ptr->width * info_ptr->pixel_depth + 7) >> 3;
}

#if defined(PNG_oFFs_SUPPORTED)
void PNGAPI
png_set_oFFs(png_structp png_ptr, png_infop info_ptr,
   png_int_32 offset_x, png_int_32 offset_y, int unit_type)
{
   png_debug1(1, "in %s storage function\n", "oFFs");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->x_offset = offset_x;
   info_ptr->y_offset = offset_y;
   info_ptr->offset_unit_type = (png_byte)unit_type;
   info_ptr->valid |= PNG_INFO_oFFs;
}
#endif

#if defined(PNG_pCAL_SUPPORTED)
void PNGAPI
png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
   png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
   png_charp units, png_charpp params)
{
   png_uint_32 length;
   int i;

   png_debug1(1, "in %s storage function\n", "pCAL");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   length = png_strlen(purpose) + 1;
   png_debug1(3, "allocating purpose for info (%lu bytes)\n", length);
   info_ptr->pcal_purpose = (png_charp)png_malloc(png_ptr, length);
   png_memcpy(info_ptr->pcal_purpose, purpose, (png_size_t)length);

   png_debug(3, "storing X0, X1, type, and nparams in info\n");
   info_ptr->pcal_X0 = X0;
   info_ptr->pcal_X1 = X1;
   info_ptr->pcal_type = (png_byte)type;
   info_ptr->pcal_nparams = (png_byte)nparams;

   length = png_strlen(units) + 1;
   png_debug1(3, "allocating units for info (%lu bytes)\n", length);
   info_ptr->pcal_units = (png_charp)png_malloc(png_ptr, length);
   png_memcpy(info_ptr->pcal_units, units, (png_size_t)length);

   info_ptr->pcal_params = (png_charpp)png_malloc(png_ptr,
      (png_uint_32)((nparams + 1) * sizeof(png_charp)));

   info_ptr->pcal_params[nparams] = NULL;

   for (i = 0; i < nparams; i++)
   {
      length = png_strlen(params[i]) + 1;
      png_debug2(3, "allocating parameter %d for info (%lu bytes)\n", i, length);
      info_ptr->pcal_params[i] = (png_charp)png_malloc(png_ptr, length);
      png_memcpy(info_ptr->pcal_params[i], params[i], (png_size_t)length);
   }

   info_ptr->valid |= PNG_INFO_pCAL;
#ifdef PNG_FREE_ME_SUPPORTED
   info_ptr->free_me |= PNG_FREE_PCAL;
#endif
}
#endif

#if defined(PNG_READ_sCAL_SUPPORTED) || defined(PNG_WRITE_sCAL_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
void PNGAPI
png_set_sCAL(png_structp png_ptr, png_infop info_ptr,
             int unit, double width, double height)
{
   png_debug1(1, "in %s storage function\n", "sCAL");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->scal_unit = (png_byte)unit;
   info_ptr->scal_pixel_width = width;
   info_ptr->scal_pixel_height = height;

   info_ptr->valid |= PNG_INFO_sCAL;
}
#else
#ifdef PNG_FIXED_POINT_SUPPORTED
void PNGAPI
png_set_sCAL_s(png_structp png_ptr, png_infop info_ptr,
             int unit, png_charp swidth, png_charp sheight)
{
   png_uint_32 length;

   png_debug1(1, "in %s storage function\n", "sCAL");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->scal_unit = (png_byte)unit;

   length = png_strlen(swidth) + 1;
   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
   info_ptr->scal_s_width = (png_charp)png_malloc(png_ptr, length);
   png_memcpy(info_ptr->scal_s_width, swidth, (png_size_t)length);

   length = png_strlen(sheight) + 1;
   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
   info_ptr->scal_s_height = (png_charp)png_malloc(png_ptr, length);
   png_memcpy(info_ptr->scal_s_height, sheight, (png_size_t)length);

   info_ptr->valid |= PNG_INFO_sCAL;
#ifdef PNG_FREE_ME_SUPPORTED
   info_ptr->free_me |= PNG_FREE_SCAL;
#endif
}
#endif
#endif
#endif

#if defined(PNG_pHYs_SUPPORTED)
void PNGAPI
png_set_pHYs(png_structp png_ptr, png_infop info_ptr,
   png_uint_32 res_x, png_uint_32 res_y, int unit_type)
{
   png_debug1(1, "in %s storage function\n", "pHYs");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->x_pixels_per_unit = res_x;
   info_ptr->y_pixels_per_unit = res_y;
   info_ptr->phys_unit_type = (png_byte)unit_type;
   info_ptr->valid |= PNG_INFO_pHYs;
}
#endif

void PNGAPI
png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
   png_colorp palette, int num_palette)
{

   png_debug1(1, "in %s storage function\n", "PLTE");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   /*
    * It may not actually be necessary to set png_ptr->palette here;
    * we do it for backward compatibility with the way the png_handle_tRNS
    * function used to do the allocation.
    */
#ifdef PNG_FREE_ME_SUPPORTED
   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
#endif
   png_ptr->palette = (png_colorp)png_zalloc(png_ptr, (uInt)num_palette,
      sizeof (png_color));
   png_memcpy(png_ptr->palette, palette, num_palette * sizeof (png_color));
   info_ptr->palette = png_ptr->palette;
   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;

#ifdef PNG_FREE_ME_SUPPORTED
   info_ptr->free_me |= PNG_FREE_PLTE;
#else
   png_ptr->flags |= PNG_FLAG_FREE_PLTE;
#endif

   info_ptr->valid |= PNG_INFO_PLTE;
}

#if defined(PNG_sBIT_SUPPORTED)
void PNGAPI
png_set_sBIT(png_structp png_ptr, png_infop info_ptr,
   png_color_8p sig_bit)
{
   png_debug1(1, "in %s storage function\n", "sBIT");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   png_memcpy(&(info_ptr->sig_bit), sig_bit, sizeof (png_color_8));
   info_ptr->valid |= PNG_INFO_sBIT;
}
#endif

#if defined(PNG_sRGB_SUPPORTED)
void PNGAPI
png_set_sRGB(png_structp png_ptr, png_infop info_ptr, int intent)
{
   png_debug1(1, "in %s storage function\n", "sRGB");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   info_ptr->srgb_intent = (png_byte)intent;
   info_ptr->valid |= PNG_INFO_sRGB;
}

void PNGAPI
png_set_sRGB_gAMA_and_cHRM(png_structp png_ptr, png_infop info_ptr,
   int intent)
{
#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
   float file_gamma;
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
   png_fixed_point int_file_gamma;
#endif
#endif
#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
   float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
   png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
      int_green_y, int_blue_x, int_blue_y;
#endif
#endif
   png_debug1(1, "in %s storage function\n", "sRGB_gAMA_and_cHRM");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   png_set_sRGB(png_ptr, info_ptr, intent);

#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
   file_gamma = (float).45455;
   png_set_gAMA(png_ptr, info_ptr, file_gamma);
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
   int_file_gamma = 45455L;
   png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
#endif
#endif

#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FIXED_POINT_SUPPORTED
   int_white_x = 31270L;
   int_white_y = 32900L;
   int_red_x   = 64000L;
   int_red_y   = 33000L;
   int_green_x = 30000L;
   int_green_y = 60000L;
   int_blue_x  = 15000L;
   int_blue_y  =  6000L;

   png_set_cHRM_fixed(png_ptr, info_ptr,
      int_white_x, int_white_y, int_red_x, int_red_y, int_green_x, int_green_y,
      int_blue_x, int_blue_y);
#endif
#ifdef PNG_FLOATING_POINT_SUPPORTED
   white_x = (float).3127;
   white_y = (float).3290;
   red_x   = (float).64;
   red_y   = (float).33;
   green_x = (float).30;
   green_y = (float).60;
   blue_x  = (float).15;
   blue_y  = (float).06;

   png_set_cHRM(png_ptr, info_ptr,
      white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
#endif
#endif
}
#endif


#if defined(PNG_iCCP_SUPPORTED)
void PNGAPI
png_set_iCCP(png_structp png_ptr, png_infop info_ptr,
             png_charp name, int compression_type,
             png_charp profile, png_uint_32 proflen)
{
   png_charp new_iccp_name;
   png_charp new_iccp_profile;

   png_debug1(1, "in %s storage function\n", "iCCP");
   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
      return;

   new_iccp_name = (png_charp)png_malloc(png_ptr, png_strlen(name)+1);
   png_strcpy(new_iccp_name, name);
   new_iccp_profile = (png_charp)png_malloc(png_ptr, proflen);
   png_memcpy(new_iccp_profile, profile, (png_size_t)proflen);

   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);

   info_ptr->iccp_proflen = proflen;
   info_ptr->iccp_name = new_iccp_name;
   info_ptr->iccp_profile = new_iccp_profile;
   /* Compression is always zero but is here so the API and info structure
    * does not have to change if we introduce multiple compression types */
   info_ptr->iccp_compression = (png_byte)compression_type;
#ifdef PNG_FREE_ME_SUPPORTED
   info_ptr->free_me |= PNG_FREE_ICCP;
#endif
   info_ptr->valid |= PNG_INFO_iCCP;
}
#endif

#if defined(PNG_TEXT_SUPPORTED)
void PNGAPI
png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
   int num_text)
{
   int i;

   png_debug1(1, "in %s storage function\n", (png_ptr->chunk_name[0] == '\0' ?
      "text" : (png_const_charp)png_ptr->chunk_name));

   if (png_ptr == NULL || info_ptr == NULL || num_text == 0)
      return;

   /* Make sure we have enough space in the "text" array in info_struct
    * to hold all of the incoming text_ptr objects.
    */
   if (info_ptr->num_text + num_text > info_ptr->max_text)
   {
      if (info_ptr->text != NULL)
      {
         png_textp old_text;
         int old_max;

         old_max = info_ptr->max_text;
         info_ptr->max_text = info_ptr->num_text + num_text + 8;
         old_text = info_ptr->text;
         info_ptr->text = (png_textp)png_malloc(png_ptr,
            (png_uint_32)(info_ptr->max_text * sizeof (png_text)));
         png_memcpy(info_ptr->text, old_text, (png_size_t)(old_max *
            sizeof(png_text)));
         png_free(png_ptr, old_text);
      }
      else
      {
         info_ptr->max_text = num_text + 8;
         info_ptr->num_text = 0;
         info_ptr->text = (png_textp)png_malloc(png_ptr,
            (png_uint_32)(info_ptr->max_text * sizeof (png_text)));
#ifdef PNG_FREE_ME_SUPPORTED
         info_ptr->free_me |= PNG_FREE_TEXT;
#endif
      }
      png_debug1(3, "allocated %d entries for info_ptr->text\n",
         info_ptr->max_text);
   }
   for (i = 0; i < num_text; i++)
   {
      png_size_t text_length,key_len;
      png_size_t lang_len,lang_key_len;
      png_textp textp = &(info_ptr->text[info_ptr->num_text]);

      if (text_ptr[i].key == NULL)
          continue;

      key_len = png_strlen(text_ptr[i].key);

      if(text_ptr[i].compression <= 0)
      {
        lang_len = 0;
        lang_key_len = 0;
      }
      else
#ifdef PNG_iTXt_SUPPORTED
      {
        /* set iTXt data */
        if (text_ptr[i].key != NULL)
          lang_len = png_strlen(text_ptr[i].lang);
        else
          lang_len = 0;
        if (text_ptr[i].lang_key != NULL)
          lang_key_len = png_strlen(text_ptr[i].lang_key);
        else
          lang_key_len = 0;
      }
#else
      {
        png_warning(png_ptr, "iTXt chunk not supported.");
        continue;
      }
#endif

      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
      {
         text_length = 0;
#ifdef PNG_iTXt_SUPPORTED
         if(text_ptr[i].compression > 0)
            textp->compression = PNG_ITXT_COMPRESSION_NONE;
         else
#endif
            textp->compression = PNG_TEXT_COMPRESSION_NONE;
      }
      else
      {
         text_length = png_strlen(text_ptr[i].text);
         textp->compression = text_ptr[i].compression;
      }

      textp->key = (png_charp)png_malloc(png_ptr,
         (png_uint_32)(key_len + text_length + lang_len + lang_key_len + 4));
      png_debug2(2, "Allocated %lu bytes at %x in png_set_text\n",
         (png_uint_32)(key_len + lang_len + lang_key_len + text_length + 4),
         (int)textp->key);

      png_memcpy(textp->key, text_ptr[i].key,
         (png_size_t)(key_len));
      *(textp->key+key_len) = '\0';
#ifdef PNG_iTXt_SUPPORTED
      if (text_ptr[i].compression > 0)
      {
         textp->lang=textp->key + key_len + 1;
         png_memcpy(textp->lang, text_ptr[i].lang, lang_len);
         *(textp->lang+lang_len) = '\0';
         textp->lang_key=textp->lang + lang_len + 1;
         png_memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
         *(textp->lang_key+lang_key_len) = '\0';
         textp->text=textp->lang_key + lang_key_len + 1;
      }
      else
#endif
      {
#ifdef PNG_iTXt_SUPPORTED
         textp->lang=(png_charp)NULL;
         textp->lang_key=(png_charp)NULL;
#endif
         textp->text=textp->key + key_len + 1;
      }
      if(text_length)
         png_memcpy(textp->text, text_ptr[i].text,
            (png_size_t)(text_length));
      *(textp->text+text_length) = '\0';

#ifdef PNG_iTXt_SUPPORTED
      if(textp->compression > 0)
      {
         textp->text_length = 0;
         textp->itxt_length = text_length;
      }
      else
#endif
      {
         textp->text_length = text_length;
#ifdef PNG_iTXt_SUPPORTED
         textp->itxt_length = 0;
#endif
      }
      info_ptr->text[info_ptr->num_text]= *textp;
      info_ptr->num_text++;
      png_debug1(3, "transferred text chunk %d\n", info_ptr->num_text);
   }
}
#endif

#if defined(PNG_tIME_SUPPORTED)
void PNGAPI
png_set_tIME(png_structp png_ptr, png_infop info_ptr, png_timep mod_time)
{
   png_debug1(1, "in %s storage function\n", "tIME");
   if (png_ptr == NULL || info_ptr == NULL ||
       (png_ptr->mode & PNG_WROTE_tIME))
      return;

   png_memcpy(&(info_ptr->mod_time), mod_time, sizeof (png_time));
   info_ptr->valid |= PNG_INFO_tIME;
}
#endif

#if defined(PNG_tRNS_SUPPORTED)
void PNGAPI
png_set_tRNS(png_structp png_ptr, png_infop info_ptr,
   png_bytep trans, int num_trans, png_color_16p trans_values)
{
   png_debug1(1, "in %s storage function\n", "tRNS");
   if (png_ptr == NULL || info_ptr == NULL)
      return;

   if (trans != NULL)
   {
       /*
	* It may not actually be necessary to set png_ptr->trans here;
	* we do it for backward compatibility with the way the png_handle_tRNS
	* function used to do the allocation.
	*/
#ifdef PNG_FREE_ME_SUPPORTED
       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
#endif
       png_ptr->trans = info_ptr->trans = (png_bytep)png_malloc(png_ptr,
           num_trans);
       png_memcpy(info_ptr->trans, trans, num_trans);
#ifdef PNG_FREE_ME_SUPPORTED
       info_ptr->free_me |= PNG_FREE_TRNS;
#else
       png_ptr->flags |= PNG_FLAG_FREE_TRNS;
#endif
   }

   if (trans_values != NULL)
   {
      png_memcpy(&(info_ptr->trans_values), trans_values,
         sizeof(png_color_16));
      if (num_trans == 0)
        num_trans = 1;
   }
   info_ptr->num_trans = (png_uint_16)num_trans;
   info_ptr->valid |= PNG_INFO_tRNS;
}
#endif

#if defined(PNG_sPLT_SUPPORTED)
void PNGAPI
png_set_sPLT(png_structp png_ptr,
             png_infop info_ptr, png_sPLT_tp entries, int nentries)
{
    png_sPLT_tp np;
    int i;

    np = (png_sPLT_tp)png_malloc(png_ptr,
        (info_ptr->splt_palettes_num + nentries) * sizeof(png_sPLT_t));

    png_memcpy(np, info_ptr->splt_palettes,
           info_ptr->splt_palettes_num * sizeof(png_sPLT_t));
    png_free(png_ptr, info_ptr->splt_palettes);
    info_ptr->splt_palettes=NULL;

    for (i = 0; i < nentries; i++)
    {
        png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
        png_sPLT_tp from = entries + i;

        to->name = (png_charp)png_malloc(png_ptr,
            png_strlen(from->name) + 1);
        png_strcpy(to->name, from->name);
        to->entries = (png_sPLT_entryp)png_malloc(png_ptr,
            from->nentries * sizeof(png_sPLT_t));
        png_memcpy(to->entries, from->entries,
            from->nentries * sizeof(png_sPLT_t));
        to->nentries = from->nentries;
        to->depth = from->depth;
    }

    info_ptr->splt_palettes = np;
    info_ptr->splt_palettes_num += nentries;
    info_ptr->valid |= PNG_INFO_sPLT;
#ifdef PNG_FREE_ME_SUPPORTED
    info_ptr->free_me |= PNG_FREE_SPLT;
#endif
}
#endif /* PNG_sPLT_SUPPORTED */

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
void PNGAPI
png_set_unknown_chunks(png_structp png_ptr,
   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns)
{
    png_unknown_chunkp np;
    int i;

    if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
        return;

    np = (png_unknown_chunkp)png_malloc(png_ptr,
        (info_ptr->unknown_chunks_num + num_unknowns) *
        sizeof(png_unknown_chunk));

    png_memcpy(np, info_ptr->unknown_chunks,
           info_ptr->unknown_chunks_num * sizeof(png_unknown_chunk));
    png_free(png_ptr, info_ptr->unknown_chunks);
    info_ptr->unknown_chunks=NULL;

    for (i = 0; i < num_unknowns; i++)
    {
        png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
        png_unknown_chunkp from = unknowns + i;

        png_strcpy((png_charp)to->name, (png_charp)from->name);
        to->data = (png_bytep)png_malloc(png_ptr, from->size);
        png_memcpy(to->data, from->data, from->size);
        to->size = from->size;

        /* note our location in the read or write sequence */
        to->location = (png_byte)(png_ptr->mode & 0xff);
    }

    info_ptr->unknown_chunks = np;
    info_ptr->unknown_chunks_num += num_unknowns;
#ifdef PNG_FREE_ME_SUPPORTED
    info_ptr->free_me |= PNG_FREE_UNKN;
#endif
}
void PNGAPI
png_set_unknown_chunk_location(png_structp png_ptr, png_infop info_ptr,
   int chunk, int location)
{
   if(png_ptr != NULL && info_ptr != NULL && chunk >= 0 && chunk <
         (int)info_ptr->unknown_chunks_num)
      info_ptr->unknown_chunks[chunk].location = (png_byte)location;
}
#endif

#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
void PNGAPI
png_permit_empty_plte (png_structp png_ptr, int empty_plte_permitted)
{
   /* This function is deprecated in favor of png_permit_mng_features()
      and will be removed from libpng-2.0.0 */
   png_debug(1, "in png_permit_empty_plte, DEPRECATED.\n");
   if (png_ptr == NULL)
      return;
   png_ptr->mng_features_permitted = (png_byte)
     ((png_ptr->mng_features_permitted & (~(PNG_FLAG_MNG_EMPTY_PLTE))) |
     ((empty_plte_permitted & PNG_FLAG_MNG_EMPTY_PLTE)));
}
#endif

#if defined(PNG_MNG_FEATURES_SUPPORTED)
png_uint_32 PNGAPI
png_permit_mng_features (png_structp png_ptr, png_uint_32 mng_features)
{
   png_debug(1, "in png_permit_mng_features\n");
   if (png_ptr == NULL)
      return (png_uint_32)0;
   png_ptr->mng_features_permitted =
     (png_byte)(mng_features & PNG_ALL_MNG_FEATURES);
   return (png_uint_32)png_ptr->mng_features_permitted;
}
#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
void PNGAPI
png_set_keep_unknown_chunks(png_structp png_ptr, int keep, png_bytep
   chunk_list, int num_chunks)
{
    png_bytep new_list, p;
    int i, old_num_chunks;
    if (num_chunks == 0)
    {
      if(keep == HANDLE_CHUNK_ALWAYS || keep == HANDLE_CHUNK_IF_SAFE)
        png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
      else
        png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;

      if(keep == HANDLE_CHUNK_ALWAYS)
        png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
      else
        png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
      return;
    }
    if (chunk_list == NULL)
      return;
    old_num_chunks=png_ptr->num_chunk_list;
    new_list=(png_bytep)png_malloc(png_ptr,5*(num_chunks+old_num_chunks));
    if(png_ptr->chunk_list != NULL)
    {
       png_memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
       png_free(png_ptr, png_ptr->chunk_list);
       png_ptr->chunk_list=NULL;
    }
    png_memcpy(new_list+5*old_num_chunks, chunk_list, 5*num_chunks);
    for (p=new_list+5*old_num_chunks+4, i=0; i<num_chunks; i++, p+=5)
       *p=(png_byte)keep;
    png_ptr->num_chunk_list=old_num_chunks+num_chunks;
    png_ptr->chunk_list=new_list;
#ifdef PNG_FREE_ME_SUPPORTED
    png_ptr->free_me |= PNG_FREE_LIST;
#endif
}
#endif

#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
void PNGAPI
png_set_read_user_chunk_fn(png_structp png_ptr, png_voidp user_chunk_ptr,
   png_user_chunk_ptr read_user_chunk_fn)
{
   png_debug(1, "in png_set_read_user_chunk_fn\n");
   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
   png_ptr->user_chunk_ptr = user_chunk_ptr;
}
#endif

#if defined(PNG_INFO_IMAGE_SUPPORTED)
void PNGAPI
png_set_rows(png_structp png_ptr, png_infop info_ptr, png_bytepp row_pointers)
{
   png_debug1(1, "in %s storage function\n", "rows");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   if(info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
   info_ptr->row_pointers = row_pointers;
   if(row_pointers)
      info_ptr->valid |= PNG_INFO_IDAT;
}
#endif

void PNGAPI
png_set_compression_buffer_size(png_structp png_ptr, png_uint_32 size)
{
    if(png_ptr->zbuf)
       png_free(png_ptr, png_ptr->zbuf);
    png_ptr->zbuf_size = (png_size_t)size;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, size);
    png_ptr->zstream.next_out = png_ptr->zbuf;
    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
}

void PNGAPI
png_set_invalid(png_structp png_ptr, png_infop info_ptr, int mask)
{
   if (png_ptr && info_ptr)
      info_ptr->valid &= ~(mask);
}



--- NEW FILE: pngwrite.c ---

/* pngwrite.c - general routines to write a PNG file
 *
 * libpng 1.0.12 - June 8, 2001
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2001 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.)
 */

/* get internal access to png.h */
#define PNG_INTERNAL
#include "png.h"
#ifdef PNG_WRITE_SUPPORTED

/* Writes all the PNG information.  This is the suggested way to use the
 * library.  If you have a new chunk to add, make a function to write it,
 * and put it in the correct location here.  If you want the chunk written
 * after the image data, put it in png_write_end().  I strongly encourage
[...1409 lines suppressed...]
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   /* swap bits of 1, 2, 4 bit packed pixel formats */
   if (transforms & PNG_TRANSFORM_PACKSWAP)
       png_set_packswap(png_ptr);
#endif

   /* ----------------------- end of transformations ------------------- */

   /* write the bits */
   if (info_ptr->valid & PNG_INFO_IDAT)
       png_write_image(png_ptr, info_ptr->row_pointers);

   /* It is REQUIRED to call this to finish writing the rest of the file */
   png_write_end(png_ptr, info_ptr);

   if(transforms == 0 || params == NULL)
      /* quiet compiler warnings */ return;
}
#endif
#endif /* PNG_WRITE_SUPPORTED */




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