pngwutil.c

hl2 source code. Do not use it illegal.

}
#endif

#if defined(PNG_WRITE_cHRM_SUPPORTED)
/* write the cHRM chunk */
void
png_write_cHRM(png_structp png_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_uint_32 itemp;
   png_byte buf[32];

   png_debug(1, "in png_write_cHRM\n");
   /* each value is saved int 1/1000000ths */
   if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
       white_x + white_y > 1.0)
   {
      png_warning(png_ptr, "Invalid cHRM white point specified");
      return;
   }
   itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
   png_save_uint_32(buf, itemp);
   itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
   png_save_uint_32(buf + 4, itemp);

   if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 ||
       red_x + red_y > 1.0)
   {
      png_warning(png_ptr, "Invalid cHRM red point specified");
      return;
   }
   itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
   png_save_uint_32(buf + 8, itemp);
   itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
   png_save_uint_32(buf + 12, itemp);

   if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 ||
       green_x + green_y > 1.0)
   {
      png_warning(png_ptr, "Invalid cHRM green point specified");
      return;
   }
   itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
   png_save_uint_32(buf + 16, itemp);
   itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
   png_save_uint_32(buf + 20, itemp);

   if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 ||
       blue_x + blue_y > 1.0)
   {
      png_warning(png_ptr, "Invalid cHRM blue point specified");
      return;
   }
   itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
   png_save_uint_32(buf + 24, itemp);
   itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
   png_save_uint_32(buf + 28, itemp);

   png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
}
#endif

#if defined(PNG_WRITE_tRNS_SUPPORTED)
/* write the tRNS chunk */
void
png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
   int num_trans, int color_type)
{
   png_byte buf[6];

   png_debug(1, "in png_write_tRNS\n");
   if (color_type == PNG_COLOR_TYPE_PALETTE)
   {
      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
      {
         png_warning(png_ptr,"Invalid number of transparent colors specified");
         return;
      }
      /* write the chunk out as it is */
      png_write_chunk(png_ptr, png_tRNS, trans, (png_size_t)num_trans);
   }
   else if (color_type == PNG_COLOR_TYPE_GRAY)
   {
      /* one 16 bit value */
      png_save_uint_16(buf, tran->gray);
      png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
   }
   else if (color_type == PNG_COLOR_TYPE_RGB)
   {
      /* three 16 bit values */
      png_save_uint_16(buf, tran->red);
      png_save_uint_16(buf + 2, tran->green);
      png_save_uint_16(buf + 4, tran->blue);
      png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
   }
   else
   {
      png_warning(png_ptr, "Can't write tRNS with an alpha channel");
   }
}
#endif

#if defined(PNG_WRITE_bKGD_SUPPORTED)
/* write the background chunk */
void
png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
{
   png_byte buf[6];

   png_debug(1, "in png_write_bKGD\n");
   if (color_type == PNG_COLOR_TYPE_PALETTE)
   {
      if (back->index > png_ptr->num_palette)
      {
         png_warning(png_ptr, "Invalid background palette index");
         return;
      }
      buf[0] = back->index;
      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
   }
   else if (color_type & PNG_COLOR_MASK_COLOR)
   {
      png_save_uint_16(buf, back->red);
      png_save_uint_16(buf + 2, back->green);
      png_save_uint_16(buf + 4, back->blue);
      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
   }
   else
   {
      png_save_uint_16(buf, back->gray);
      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
   }
}
#endif

#if defined(PNG_WRITE_hIST_SUPPORTED)
/* write the histogram */
void
png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
{
   int i;
   png_byte buf[3];

   png_debug(1, "in png_write_hIST\n");
   if (num_hist > (int)png_ptr->num_palette)
   {
      png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
         png_ptr->num_palette);
      png_warning(png_ptr, "Invalid number of histogram entries specified");
      return;
   }

   png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
   for (i = 0; i < num_hist; i++)
   {
      png_save_uint_16(buf, hist[i]);
      png_write_chunk_data(png_ptr, buf, (png_size_t)2);
   }
   png_write_chunk_end(png_ptr);
}
#endif

#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED) || \
    defined(PNG_WRITE_pCAL_SUPPORTED)
/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
 * and if invalid, correct the keyword rather than discarding the entire
 * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
 * length, forbids leading or trailing whitespace, multiple internal spaces,
 * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
 *
 * The new_key is allocated to hold the corrected keyword and must be freed
 * by the calling routine.  This avoids problems with trying to write to
 * static keywords without having to have duplicate copies of the strings.
 */
png_size_t
png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
{
   png_size_t key_len;
   png_charp kp, dp;
   int kflag;

   png_debug(1, "in png_check_keyword\n");
   *new_key = NULL;

   if (key == NULL || (key_len = png_strlen(key)) == 0)
   {
      png_chunk_warning(png_ptr, "zero length keyword");
      return ((png_size_t)0);
   }

   png_debug1(2, "Keyword to be checked is '%s'\n", key);

   *new_key = (png_charp)png_malloc(png_ptr, (png_uint_32)(key_len + 1));

   /* Replace non-printing characters with a blank and print a warning */
   for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
   {
      if (*kp < 0x20 || (*kp > 0x7E && (png_byte)*kp < 0xA1))
      {
#if !defined(PNG_NO_STDIO)
         char msg[40];

         sprintf(msg, "invalid keyword character 0x%02X", *kp);
         png_chunk_warning(png_ptr, msg);
#else
         png_chunk_warning(png_ptr, "invalid character in keyword");
#endif
         *dp = ' ';
      }
      else
      {
         *dp = *kp;
      }
   }
   *dp = '\0';

   /* Remove any trailing white space. */
   kp = *new_key + key_len - 1;
   if (*kp == ' ')
   {
      png_chunk_warning(png_ptr, "trailing spaces removed from keyword");

      while (*kp == ' ')
      {
        *(kp--) = '\0';
        key_len--;
      }
   }

   /* Remove any leading white space. */
   kp = *new_key;
   if (*kp == ' ')
   {
      png_chunk_warning(png_ptr, "leading spaces removed from keyword");

      while (*kp == ' ')
      {
        kp++;
        key_len--;
      }
   }

   png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);

   /* Remove multiple internal spaces. */
   for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
   {
      if (*kp == ' ' && kflag == 0)
      {
         *(dp++) = *kp;
         kflag = 1;
      }
      else if (*kp == ' ')
      {
         key_len--;
      }
      else
      {
         *(dp++) = *kp;
         kflag = 0;
      }
   }
   *dp = '\0';

   if (key_len == 0)
   {
      png_chunk_warning(png_ptr, "zero length keyword");
   }

   if (key_len > 79)
   {
      png_chunk_warning(png_ptr, "keyword length must be 1 - 79 characters");
      new_key[79] = '\0';
      key_len = 79;
   }

   return (key_len);
}
#endif

#if defined(PNG_WRITE_tEXt_SUPPORTED)
/* write a tEXt chunk */
void
png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
   png_size_t text_len)
{
   png_size_t key_len;
   png_charp new_key;

   png_debug(1, "in png_write_tEXt\n");
   if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
   {
      png_warning(png_ptr, "Empty keyword in tEXt chunk");
      return;
   }

   if (text == NULL || *text == '\0')
      text_len = 0;

   /* make sure we include the 0 after the key */
   png_write_chunk_start(png_ptr, png_tEXt, (png_uint_32)key_len+text_len+1);
   png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
   if (text_len)
      png_write_chunk_data(png_ptr, (png_bytep)text, text_len);

   png_write_chunk_end(png_ptr);
   png_free(png_ptr, new_key);
}
#endif

#if defined(PNG_WRITE_zTXt_SUPPORTED)
/* write a compressed text chunk */
void
png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
   png_size_t text_len, int compression)
{
   png_size_t key_len;
   char buf[1];
   png_charp new_key;
   int i, ret;
   png_charpp output_ptr = NULL; /* array of pointers to output */
   int num_output_ptr = 0; /* number of output pointers used */
   int max_output_ptr = 0; /* size of output_ptr */

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

   if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
   {
      png_warning(png_ptr, "Empty keyword in zTXt chunk");
      return;
   }

   if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
   {
      png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
      png_free(png_ptr, new_key);
      return;
   }

   png_free(png_ptr, new_key);

   if (compression >= PNG_TEXT_COMPRESSION_LAST)
   {
#if !defined(PNG_NO_STDIO)
      char msg[50];
      sprintf(msg, "Unknown zTXt compression type %d", compression);
      png_warning(png_ptr, msg);
#else
      png_warning(png_ptr, "Unknown zTXt compression type");
#endif
      compression = PNG_TEXT_COMPRESSION_zTXt;
   }

   /* We can't write the chunk until we find out how much data we have,
    * which means we need to run the compressor first and save the
    * output.  This shouldn't be a problem, as the vast majority of
    * comments should be reasonable, but we will set up an array of
    * malloc'd pointers to be sure.
    *
    * If we knew the application was well behaved, we could simplify this
    * greatly by assuming we can always malloc an output buffer large
    * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
    * and malloc this directly.  The only time this would be a bad idea is
    * if we can't malloc more than 64K and we have 64K of random input
    * data, or if the input string is incredibly large (although this
    * wouldn't cause a failure, just a slowdown due to swapping).
    */

   /* set up the compression buffers */
   png_ptr->zstream.avail_in = (uInt)text_len;
   png_ptr->zstream.next_in = (Bytef *)text;
   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
   png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;

   /* this is the same compression loop as in png_write_row() */
   do
   {
      /* compress the data */
      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
      if (ret != Z_OK)
      {
         /* error */
         if (png_ptr->zstream.msg != NULL)
            png_error(png_ptr, png_ptr->zstream.msg);
         else
            png_error(png_ptr, "zlib error");
      }
      /* check to see if we need more room */
      if (!png_ptr->zstream.avail_out && png_ptr->zstream.avail_in)
      {
         /* make sure the output array has room */
         if (num_output_ptr >= max_output_ptr)
         {
            int old_max;

            old_max = max_output_ptr;
            max_output_ptr = num_output_ptr + 4;
            if (output_ptr != NULL)
            {
               png_charpp old_ptr;

               old_ptr = output_ptr;
               output_ptr = (png_charpp)png_malloc(png_ptr,
                  (png_uint_32)(max_output_ptr * sizeof (png_charpp)));
               png_memcpy(output_ptr, old_ptr, old_max * sizeof (png_charp));
               png_free(png_ptr, old_ptr);
            }
            else
               output_ptr = (png_charpp)png_malloc(png_ptr,
                  (png_uint_32)(max_output_ptr * sizeof (png_charp)));
         }