kc3-lang/libpng/contrib/libtests/fakepng.c

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• Hash : b9c62013
  Author :
  Date : 2015-11-12T07:00:12
  

  [master] Imported from libpng-1.6.19.tar
  

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• contrib/libtests/fakepng.c

• /* Fake a PNG - just write it out directly.
   *
   * COPYRIGHT: Written by John Cunningham Bowler, 2014.
   * To the extent possible under law, the author has waived all copyright and
   * related or neighboring rights to this work.  This work is published from:
   * United States.
   *
   */
  
  #include <stdio.h>
  #include <zlib.h> /* for crc32 */
  
  void
  put_uLong(uLong val)
  {
     putchar(val >> 24);
     putchar(val >> 16);
     putchar(val >>  8);
     putchar(val >>  0);
  }
  
  void
  put_chunk(const unsigned char *chunk, uInt length)
  {
     uLong crc;
  
     put_uLong(length-4); /* Exclude the tag */
  
     fwrite(chunk, length, 1, stdout);
  
     crc = crc32(0, Z_NULL, 0);
     put_uLong(crc32(crc, chunk, length));
  }
  
  const unsigned char signature[] =
  {
     137, 80, 78, 71, 13, 10, 26, 10
  };
  
  const unsigned char IHDR[] =
  {
     73, 72, 68, 82, /* IHDR */
     0, 0, 0, 1, /* width */
     0, 0, 0, 1, /* height */
     1, /* bit depth */
     0, /* color type: greyscale */
     0, /* compression method */
     0, /* filter method */
     0  /* interlace method: none */
  };
  
  const unsigned char unknown[] =
  {
     'u', 'n', 'K', 'n' /* "unKn" - private safe to copy */
  };
  
  int
  main(void)
  {
     fwrite(signature, sizeof signature, 1, stdout);
     put_chunk(IHDR, sizeof IHDR);
  
     for (;;)
        put_chunk(unknown, sizeof unknown);
  }
  

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