pngtest.c

hl2 source code. Do not use it illegal.

/* pngtest.c - a simple test program to test libpng
 *
 * libpng 1.0.3 -January 14, 1999
 * 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
 * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
 *
 * 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 chunk size is not 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.  You can also test a number
 * of files at once by typing "pngtest -m file1.png file2.png ..."
 */

#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"

#if defined(PNG_TIME_RFC1123_SUPPORTED)
static int tIME_chunk_present=0;
static char tIME_string[30] = "no tIME chunk present in file";
#endif /* PNG_TIME_RFC1123_SUPPORTED */

int test_one_file PNGARG((PNG_CONST char *inname, PNG_CONST char *outname));

#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 */

/* example of using row callbacks to make a simple progress meter */
static int status_pass=1;
static int status_dots_requested=0;
static int status_dots=1;

void
read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
{
    if(png_ptr == NULL || row_number > 0x3fffffffL) return;
    if(status_pass != pass)
    {
       fprintf(stdout,"\n Pass %d: ",pass);
       status_pass = pass;
       status_dots = 30;
    }
    status_dots--;
    if(status_dots == 0)
    {
       fprintf(stdout, "\n         ");
       status_dots=30;
    }
    fprintf(stdout, "r");
}

void
write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
{
    if(png_ptr == NULL || row_number > 0x3fffffffL || pass > 7) return;
    fprintf(stdout, "w");
}


#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
/* example of using user transform callback (we don't transform anything,
   but merely count the zero samples) */

static png_uint_32 zero_samples;

void
count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
{
   png_bytep dp = data;
   if(png_ptr == NULL)return;

   /* contents of 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)
    */

    /* counts the number of zero samples (or zero pixels if color_type is 3 */

    if(row_info->color_type == 0 || row_info->color_type == 3)
    {
       int pos=0;
       png_uint_32 n, nstop;
       for (n=0, nstop=row_info->width; n<nstop; n++)
       {
          if(row_info->bit_depth == 1)
          {
             if(((*dp << pos++ )& 0x80) == 0) zero_samples++;
             if(pos == 8)
             {
                pos = 0;
                dp++;
             }
          }
          if(row_info->bit_depth == 2)
          {
             if(((*dp << (pos+=2))& 0xc0) == 0) zero_samples++;
             if(pos == 8)
             {
                pos = 0;
                dp++;
             }
          }
          if(row_info->bit_depth == 4)
          {
             if(((*dp << (pos+=4))& 0xf0) == 0) zero_samples++;
             if(pos == 8)
             {
                pos = 0;
                dp++;
             }
          }
          if(row_info->bit_depth == 8)
             if(*dp++ == 0) zero_samples++;
          if(row_info->bit_depth == 16)
          {
             if((*dp | *(dp+1)) == 0) zero_samples++;
             dp+=2;
          }
       }
    }
    else /* other color types */
    {
       png_uint_32 n, nstop;
       int channel;
       int color_channels = row_info->channels;
       if(row_info->color_type > 3)color_channels--;

       for (n=0, nstop=row_info->width; n<nstop; n++)
       {
          for (channel = 0; channel < color_channels; channel++)
          {
             if(row_info->bit_depth == 8)
                if(*dp++ == 0) zero_samples++;
             if(row_info->bit_depth == 16)
             {
                if((*dp | *(dp+1)) == 0) zero_samples++;
                dp+=2;
             }
          }
          if(row_info->color_type > 3)
          {
             dp++;
             if(row_info->bit_depth == 16)dp++;
          }
       }
    }
}
#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */

static int verbose = 0;
static int wrote_question = 0;

#if defined(PNG_NO_STDIO)
/* 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. */
/* 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
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 /* USE_FAR_KEYWORD */

#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 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
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 /* USE_FAR_KEYWORD */

/* 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. */