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src/Source/LibPNG/pngtest.c  view on Meta::CPAN

/* pngtest.c - a simple test program to test libpng
 *
 * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 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 code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 *
 * 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
 *    exist in the input file.
 * 4) others not listed here...
 * In these cases, it is best to check with another tool such as "pngcheck"
 * to see what the differences between the two files are.
 *
 * If a filename is given on the command-line, then this file is used
 * for the input, rather than the default "pngtest.png".  This allows
 * testing a wide variety of files easily.  You can also test a number
 * of files at once by typing "pngtest -m file1.png file2.png ..."
 */

#define _POSIX_SOURCE 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Defined so I can write to a file on gui/windowing platforms */
/*  #define STDERR stderr  */
#define STDERR stdout   /* For DOS */

#include "png.h"

/* Known chunks that exist in pngtest.png must be supported or pngtest will fail
 * simply as a result of re-ordering them.  This may be fixed in 1.7
 *
 * pngtest allocates a single row buffer for each row and overwrites it,
 * therefore if the write side doesn't support the writing of interlaced images
 * nothing can be done for an interlaced image (and the code below will fail
 * horribly trying to write extra data after writing garbage).
 */
#if defined PNG_READ_SUPPORTED && /* else nothing can be done */\
   defined PNG_READ_bKGD_SUPPORTED &&\
   defined PNG_READ_cHRM_SUPPORTED &&\
   defined PNG_READ_gAMA_SUPPORTED &&\
   defined PNG_READ_oFFs_SUPPORTED &&\
   defined PNG_READ_pCAL_SUPPORTED &&\
   defined PNG_READ_pHYs_SUPPORTED &&\
   defined PNG_READ_sBIT_SUPPORTED &&\
   defined PNG_READ_sCAL_SUPPORTED &&\
   defined PNG_READ_sRGB_SUPPORTED &&\
   defined PNG_READ_tEXt_SUPPORTED &&\
   defined PNG_READ_tIME_SUPPORTED &&\
   defined PNG_READ_zTXt_SUPPORTED &&\
   defined PNG_WRITE_INTERLACING_SUPPORTED

#ifdef PNG_ZLIB_HEADER
#  include PNG_ZLIB_HEADER /* defined by pnglibconf.h from 1.7 */
#else
#  include "zlib.h"
#endif

/* Copied from pngpriv.h but only used in error messages below. */
#ifndef PNG_ZBUF_SIZE
#  define PNG_ZBUF_SIZE 8192
#endif
#define FCLOSE(file) fclose(file)

#ifndef PNG_STDIO_SUPPORTED
typedef FILE                * png_FILE_p;
#endif

/* Makes pngtest verbose so we can find problems. */