pngtest.c

/* pngtest.c - a simple test program to test libpng
 *
 * libpng 1.00.97
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
 * Copyright (c) 1996, 1997 Andreas Dilger
 * May 28, 1997
 *
 * 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 fail in certain legitimate cases:
 * 1) when the compression level or filter selection method is changed.
 * 2) when the chunk size is smaller than 8K.
 * 3) unknown ancillary 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 images 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.
 */

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

/* Makes pngtest verbose so we can find problems (needs to be before png.h) */
#ifndef PNG_DEBUG
#define PNG_DEBUG 0
#endif

#include "png.h"

#ifdef __TURBOC__
#include <mem.h>
#endif

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

/* START of code to validate stdio-free compilation */
/* These copies of the default read/write functions come from pngrio.c and */
/* pngwio.c.  They allow "don't include stdio" testing of the library. */
#if defined(PNG_NO_STDIO)
/* This is the function which 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
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.
    */
   check = (png_size_t)fread(data, (png_size_t)1, length,
      (FILE *)png_ptr->io_ptr);

   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
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   int check;
   png_byte *n_data;
   FILE *io_ptr;

   /* Check if data really is near. If so, use usual code. */
   n_data = (png_byte *)CVT_PTR_NOCHECK(data);
   io_ptr = (FILE *)CVT_PTR(png_ptr->io_ptr);
   if ((png_bytep)n_data == data)
   {
      check = fread(n_data, 1, length, io_ptr);
   }
   else
   {
      png_byte buf[NEAR_BUF_SIZE];
      png_size_t read, remaining, err;
      check = 0;
      remaining = length;
      do
      {
         read = MIN(NEAR_BUF_SIZE, remaining);
         err = fread(buf, (png_size_t)1, read, io_ptr);
         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 (check != length)
   {
      png_error(png_ptr, "read Error");
   }
}
#endif

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
static void
png_default_flush(png_structp png_ptr)
{
   FILE *io_ptr;
   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));
   if (io_ptr != NULL)
      fflush(io_ptr);
}
#endif

/* This is the function which 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
png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
   png_uint_32 check;

   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));
   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
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" */
   FILE *io_ptr;

   /* Check if data really is near. If so, use usual code. */
   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
   io_ptr = (FILE *)CVT_PTR(png_ptr->io_ptr);
   if ((png_bytep)near_data == data)
   {
      check = fwrite(near_data, 1, length, io_ptr);
   }
   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 */
         err = fwrite(buf, 1, written, io_ptr);
         if (err != written)
            break;
         else
            check += err;
         data += written;
         remaining -= written;
      }
      while (remaining != 0);
   }
   if (check != length)
   {
      png_error(png_ptr, "Write Error");
   }
}

#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 to.  In the default configuration, png_ptr is
 * not used, but it is passed in case it may be useful.
 */
static void
png_default_warning(png_structp png_ptr, png_const_charp message)
{
   PNG_CONST char *name = "UNKNOWN (ERROR!)";
   if (png_ptr != NULL && png_ptr->error_ptr != NULL)
      name = png_ptr->error_ptr;
   fprintf(STDERR, "%s: libpng warning: %s\n", name, message);
}

/* 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
png_default_error(png_structp png_ptr, png_const_charp message)
{
   png_default_warning(png_ptr, message);
   /* We can return because png_error calls the default handler which is
    * actually ok in this case. */
}
#endif
/* END of code to validate stdio-free compilation */

/* Test one file */
int test(PNG_CONST char *inname, PNG_CONST char *outname)
{
   FILE *fpin, *fpout;
   png_structp read_ptr, write_ptr;
   png_infop read_info_ptr, write_info_ptr, end_info_ptr;
   png_bytep row_buf;
   png_uint_32 y;
   png_uint_32 width, height;
   int num_pass, pass;
   int bit_depth, color_type;
#ifdef USE_FAR_KEYWORD
   jmp_buf jmpbuf;
#endif   
   
   char inbuf[256], outbuf[256];

   row_buf = (png_bytep)NULL;

   if ((fpin = fopen(inname, "rb")) == NULL)
   {
      fprintf(STDERR, "Could not find input file %s\n", inname);
      return 1;
   }

   if ((fpout = fopen(outname, "wb")) == NULL)
   {
      fprintf(STDERR, "Could not open output file %s\n", outname);
      fclose(fpin);
      return 1;
   }

   png_debug(0, "Allocating read and write structures\n");
   read_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
      (png_error_ptr)NULL, (png_error_ptr)NULL);
#if defined(PNG_NO_STDIO)
   png_set_error_fn(read_ptr, (png_voidp)inname, png_default_error, png_default_warning);
#endif
   write_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
      (png_error_ptr)NULL, (png_error_ptr)NULL);
#if defined(PNG_NO_STDIO)
   png_set_error_fn(write_ptr, (png_voidp)inname, png_default_error, png_default_warning);
#endif
   png_debug(0, "Allocating read_info, write_info and end_info structures\n");
   read_info_ptr = png_create_info_struct(read_ptr);
   write_info_ptr = png_create_info_struct(read_ptr);
   end_info_ptr = png_create_info_struct(read_ptr);

   png_debug(0, "Setting jmpbuf for read struct\n");
#ifdef USE_FAR_KEYWORD
   if (setjmp(jmpbuf))
#else
   if (setjmp(read_ptr->jmpbuf))
#endif
   {
      fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname);
      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
      png_destroy_write_struct(&write_ptr, &write_info_ptr);
      fclose(fpin);
      fclose(fpout);
      return 1;
   }

   png_debug(0, "Setting jmpbuf for write struct\n");
#ifdef USE_FAR_KEYWORD
   png_memcpy(read_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
   if (setjmp(jmpbuf))
#else
   if (setjmp(write_ptr->jmpbuf))
#endif
   {
      fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname);
      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
      png_destroy_write_struct(&write_ptr, &write_info_ptr);
      fclose(fpin);
      fclose(fpout);
      return 1;
   }

#ifdef USE_FAR_KEYWORD
   png_memcpy(write_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
#endif
   png_debug(0, "Initializing input and output streams\n");
#if !defined(PNG_NO_STDIO)
   png_init_io(read_ptr, fpin);
   png_init_io(write_ptr, fpout);
#else
   png_set_read_fn(read_ptr, (png_voidp)fpin, png_default_read_data);
   png_set_write_fn(write_ptr, (png_voidp)fpout,  png_default_write_data,
#if defined(PNG_WRITE_FLUSH_SUPPORTED)
      png_default_flush);
#else
      NULL);
#endif
#endif

   png_debug(0, "Reading info struct\n");
   png_read_info(read_ptr, read_info_ptr);

   png_debug(0, "Transferring info struct\n");
   {
      int interlace_type, compression_type, filter_type;

      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
          &color_type, &interlace_type, &compression_type, &filter_type))
      {
         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
            color_type, interlace_type, compression_type, filter_type);
      }
   }
#if defined(PNG_READ_bKGD_SUPPORTED) && defined(PNG_WRITE_bKGD_SUPPORTED)
   {
      png_color_16p background;

      if (png_get_bKGD(read_ptr, read_info_ptr, &background))
      {
         png_set_bKGD(write_ptr, write_info_ptr, background);
      }
   }
#endif
#if defined(PNG_READ_cHRM_SUPPORTED) && defined(PNG_WRITE_cHRM_SUPPORTED)
   {
      double white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;

      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
         &red_y, &green_x, &green_y, &blue_x, &blue_y))
      {
         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
      }
   }
#endif
#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_WRITE_gAMA_SUPPORTED)
   {
      double gamma;

      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
      {
         png_set_gAMA(write_ptr, write_info_ptr, gamma);
      }
   }
#endif
#if defined(PNG_READ_sRGB_SUPPORTED) && defined(PNG_WRITE_sRGB_SUPPORTED)
   {
      png_byte intent;

      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
      {
         png_set_sRGB(write_ptr, write_info_ptr, intent);
      }
   }
#endif
#if defined(PNG_READ_hIST_SUPPORTED) && defined(PNG_WRITE_hIST_SUPPORTED)
   {
      png_uint_16p hist;

      if (png_get_hIST(read_ptr, read_info_ptr, &hist))
      {
         png_set_hIST(write_ptr, write_info_ptr, hist);
      }
   }
#endif
#if defined(PNG_READ_oFFs_SUPPORTED) && defined(PNG_WRITE_oFFs_SUPPORTED)
   {
      png_uint_32 offset_x, offset_y;
      int unit_type;

      if (png_get_oFFs(read_ptr, read_info_ptr,&offset_x,&offset_y,&unit_type))
      {
         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
      }
   }
#endif
#if defined(PNG_READ_pCAL_SUPPORTED) && defined(PNG_WRITE_pCAL_SUPPORTED)
   {
      png_charp purpose, units;
      png_charpp params;
      png_int_32 X0, X1;
      int type, nparams;

      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
         &nparams, &units, &params))
      {
         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
            nparams, units, params);
      }
   }
#endif
#if defined(PNG_READ_pHYs_SUPPORTED) && defined(PNG_WRITE_pHYs_SUPPORTED)
   {
      png_uint_32 res_x, res_y;
      int unit_type;

      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
      {
         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
      }
   }
#endif
   {
      png_colorp palette;
      int num_palette;

      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
      {
         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
      }
   }
#if defined(PNG_READ_sBIT_SUPPORTED) && defined(PNG_WRITE_sBIT_SUPPORTED)
   {
      png_color_8p sig_bit;

      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
      {
         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
      }
   }
#endif
#if (defined(PNG_READ_tEXt_SUPPORTED) && defined(PNG_WRITE_tEXt_SUPPORTED)) || \
    (defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED))
   {
      png_textp text_ptr;
      int num_text;

      if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)
      {
         png_debug1(0, "Handling %d tEXt/zTXt chunks\n", num_text);
         png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);
      }
   }
#endif
#if defined(PNG_READ_tIME_SUPPORTED) && defined(PNG_WRITE_tIME_SUPPORTED)
   {
      png_timep mod_time;

      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))
      {
         png_set_tIME(write_ptr, write_info_ptr, mod_time);
      }
   }
#endif
#if defined(PNG_READ_tRNS_SUPPORTED) && defined(PNG_WRITE_tRNS_SUPPORTED)
   {
      png_bytep trans;
      int num_trans;
      png_color_16p trans_values;

      if (png_get_tRNS(read_ptr, read_info_ptr, &trans, &num_trans,
         &trans_values))
      {
         png_set_tRNS(write_ptr, write_info_ptr, trans, num_trans,
            trans_values);
      }
   }
#endif

   png_debug(0, "\nWriting info struct\n");
   png_write_info(write_ptr, write_info_ptr);

   row_buf = (png_bytep)png_malloc(read_ptr, 
      png_get_rowbytes(read_ptr, read_info_ptr));
   if (row_buf == NULL)
   {
      fprintf(STDERR, "No memory to allocate row buffer\n");
      png_destroy_read_struct(&read_ptr, &read_info_ptr, (png_infopp)NULL);
      png_destroy_write_struct(&write_ptr, &write_info_ptr);
      fclose(fpin);
      fclose(fpout);
      return 1;
   }

   num_pass = png_set_interlace_handling(read_ptr);
   png_set_interlace_handling(write_ptr);

   for (pass = 0; pass < num_pass; pass++)
   {
      for (y = 0; y < height; y++)
      {
         png_read_rows(read_ptr, (png_bytepp)&row_buf, (png_bytepp)NULL, 1);
         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);
      }
   }

   png_debug(0, "Reading and writing end_info data\n");
   png_read_end(read_ptr, end_info_ptr);
   png_write_end(write_ptr, end_info_ptr);

   png_debug(0, "Destroying data structs\n");
   png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
   png_destroy_write_struct(&write_ptr, &write_info_ptr);

   fclose(fpin);
   fclose(fpout);

   png_free(read_ptr, row_buf);

   png_debug(0, "Opening files for comparison\n");
   if ((fpin = fopen(inname, "rb")) == NULL)
   {
      fprintf(STDERR, "Could not find file %s\n", inname);
      return 1;
   }

   if ((fpout = fopen(outname, "rb")) == NULL)
   {
      fprintf(STDERR, "Could not find file %s\n", outname);
      fclose(fpin);
      return 1;
   }

   while (1)
   {
      png_size_t num_in, num_out;

      num_in = fread(inbuf, 1, 1, fpin);
      num_out = fread(outbuf, 1, 1, fpout);

      if (num_in != num_out)
      {
         fprintf(STDERR, "Files %s and %s are of a different size\n",
                 inname, outname);
         fclose(fpin);
         fclose(fpout);
         return 1;
      }

      if (!num_in)
         break;

      if (png_memcmp(inbuf, outbuf, num_in))
      {
         fprintf(STDERR, "Files %s and %s are different\n", inname, outname);
         fclose(fpin);
         fclose(fpout);
         return 1;
      }
   }

   fclose(fpin);
   fclose(fpout);

   return 0;
}

/* input and output filenames */
#ifdef RISCOS
PNG_CONST char *inname = "pngtest_png";
PNG_CONST char *outname = "pngout_png";
#else
PNG_CONST char *inname = "pngtest.png";
PNG_CONST char *outname = "pngout.png";
#endif

int
main(int argc, char *argv[])
{
   int multiple = 0;
   int ierror = 0;

   fprintf(STDERR, "Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);

   if (strcmp(png_libpng_ver, PNG_LIBPNG_VER_STRING))
   {
      fprintf(STDERR,
         "Warning: versions are different between png.h and png.c\n");
      fprintf(STDERR, "  png.h version: %s\n", PNG_LIBPNG_VER_STRING);
      fprintf(STDERR, "  png.c version: %s\n\n", png_libpng_ver);
      ++ierror;
   }

   if (argc > 1)
   {
   if (strcmp(argv[1], "-m") == 0)
      multiple = 1;
   else
      inname = argv[1];
   }

   if (!multiple && argc == 3)
     outname = argv[2];

   if (!multiple && argc > 3 || multiple && argc < 2)
   {
     fprintf(STDERR, "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
        argv[0], argv[0]);
     fprintf(STDERR, "  reads/writes one PNG file (without -m) or multiple files (-m)\n");
     fprintf(STDERR, "  with -m %s is used as a temporary file\n", outname);
     exit(1);
   }

   if (multiple)
   {
      int i;
      for (i=2; i<argc; ++i)
         ierror += test(argv[i], outname);
   }
   else
   {
      ierror += test(inname, outname);
   }

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