/* Read the information before the actual image data.  This has been
 * changed in v0.90 to allow reading a file that already has the magic
 * bytes read from the stream.  You can tell libpng how many bytes have
 * been read from the beginning of the stream (up to the maximum of 8)
 * via png_set_sig_bytes(), and we will only check the remaining bytes
 * here.  The application can then have access to the signature bytes we
 * read if it is determined that this isn't a valid PNG file.
 */
void PNGAPI
png_read_info(png_structp png_ptr, png_infop info_ptr)
{
   png_debug(1, "in png_read_info");

   if (png_ptr == NULL || info_ptr == NULL)
      return;

   /* Read and check the PNG file signature. */
   png_read_sig(png_ptr, info_ptr);

   for (;;)
   {
      PNG_IHDR;
      PNG_IDAT;
      PNG_IEND;
      PNG_PLTE;
#ifdef PNG_READ_bKGD_SUPPORTED
      PNG_bKGD;
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
      PNG_cHRM;
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
      PNG_gAMA;
#endif
#ifdef PNG_READ_hIST_SUPPORTED
      PNG_hIST;
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
      PNG_iCCP;
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
      PNG_iTXt;
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
      PNG_oFFs;
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
      PNG_pCAL;
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
      PNG_pHYs;
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
      PNG_sBIT;
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
      PNG_sCAL;
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
      PNG_sPLT;
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
      PNG_sRGB;
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
      PNG_tEXt;
#endif
#ifdef PNG_READ_tIME_SUPPORTED
      PNG_tIME;
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
      PNG_tRNS;
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
      PNG_zTXt;
#endif
      png_uint_32 length = png_read_chunk_header(png_ptr);
      PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;

      /* This should be a binary subdivision search or a hash for
       * matching the chunk name rather than a linear search.
       */
      if (!png_memcmp(chunk_name, png_IDAT, 4))
        if (png_ptr->mode & PNG_AFTER_IDAT)
          png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      if (!png_memcmp(chunk_name, png_IHDR, 4))
         png_handle_IHDR(png_ptr, info_ptr, length);
      else if (!png_memcmp(chunk_name, png_IEND, 4))
         png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
      else if (png_handle_as_unknown(png_ptr, chunk_name))
      {
         if (!png_memcmp(chunk_name, png_IDAT, 4))
            png_ptr->mode |= PNG_HAVE_IDAT;
         png_handle_unknown(png_ptr, info_ptr, length);
         if (!png_memcmp(chunk_name, png_PLTE, 4))
            png_ptr->mode |= PNG_HAVE_PLTE;
         else if (!png_memcmp(chunk_name, png_IDAT, 4))
         {
            if (!(png_ptr->mode & PNG_HAVE_IHDR))
               png_error(png_ptr, "Missing IHDR before IDAT");
            else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                     !(png_ptr->mode & PNG_HAVE_PLTE))
               png_error(png_ptr, "Missing PLTE before IDAT");
            break;
         }
      }
#endif
      else if (!png_memcmp(chunk_name, png_PLTE, 4))
         png_handle_PLTE(png_ptr, info_ptr, length);
      else if (!png_memcmp(chunk_name, png_IDAT, 4))
      {
         if (!(png_ptr->mode & PNG_HAVE_IHDR))
            png_error(png_ptr, "Missing IHDR before IDAT");
         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                  !(png_ptr->mode & PNG_HAVE_PLTE))
            png_error(png_ptr, "Missing PLTE before IDAT");

         png_ptr->idat_size = length;
         png_ptr->mode |= PNG_HAVE_IDAT;
         break;
      }
#ifdef PNG_READ_bKGD_SUPPORTED
      else if (!png_memcmp(chunk_name, png_bKGD, 4))
         png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
      else if (!png_memcmp(chunk_name, png_cHRM, 4))
         png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
      else if (!png_memcmp(chunk_name, png_gAMA, 4))
         png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_hIST_SUPPORTED
      else if (!png_memcmp(chunk_name, png_hIST, 4))
         png_handle_hIST(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
      else if (!png_memcmp(chunk_name, png_oFFs, 4))
         png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
      else if (!png_memcmp(chunk_name, png_pCAL, 4))
         png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sCAL, 4))
         png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
      else if (!png_memcmp(chunk_name, png_pHYs, 4))
         png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sBIT, 4))
         png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sRGB, 4))
         png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
      else if (!png_memcmp(chunk_name, png_iCCP, 4))
         png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sPLT, 4))
         png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tEXt, 4))
         png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tIME_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tIME, 4))
         png_handle_tIME(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tRNS, 4))
         png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_zTXt, 4))
         png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_iTXt, 4))
         png_handle_iTXt(png_ptr, info_ptr, length);
#endif
      else
         png_handle_unknown(png_ptr, info_ptr, length);
   }
}
/* Read the end of the PNG file.  Will not read past the end of the
 * file, will verify the end is accurate, and will read any comments
 * or time information at the end of the file, if info is not NULL.
 */
void PNGAPI
png_read_end(png_structp png_ptr, png_infop info_ptr)
{
   png_debug(1, "in png_read_end");

   if (png_ptr == NULL)
      return;
   png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */

   do
   {
      PNG_IHDR;
      PNG_IDAT;
      PNG_IEND;
      PNG_PLTE;
#ifdef PNG_READ_bKGD_SUPPORTED
      PNG_bKGD;
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
      PNG_cHRM;
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
      PNG_gAMA;
#endif
#ifdef PNG_READ_hIST_SUPPORTED
      PNG_hIST;
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
      PNG_iCCP;
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
      PNG_iTXt;
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
      PNG_oFFs;
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
      PNG_pCAL;
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
      PNG_pHYs;
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
      PNG_sBIT;
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
      PNG_sCAL;
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
      PNG_sPLT;
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
      PNG_sRGB;
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
      PNG_tEXt;
#endif
#ifdef PNG_READ_tIME_SUPPORTED
      PNG_tIME;
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
      PNG_tRNS;
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
      PNG_zTXt;
#endif
      png_uint_32 length = png_read_chunk_header(png_ptr);
      PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;

      if (!png_memcmp(chunk_name, png_IHDR, 4))
         png_handle_IHDR(png_ptr, info_ptr, length);
      else if (!png_memcmp(chunk_name, png_IEND, 4))
         png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
      else if (png_handle_as_unknown(png_ptr, chunk_name))
      {
         if (!png_memcmp(chunk_name, png_IDAT, 4))
         {
            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
               png_benign_error(png_ptr, "Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length);
         if (!png_memcmp(chunk_name, png_PLTE, 4))
            png_ptr->mode |= PNG_HAVE_PLTE;
      }
#endif
      else if (!png_memcmp(chunk_name, png_IDAT, 4))
      {
         /* Zero length IDATs are legal after the last IDAT has been
          * read, but not after other chunks have been read.
          */
         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
            png_benign_error(png_ptr, "Too many IDATs found");
         png_crc_finish(png_ptr, length);
      }
      else if (!png_memcmp(chunk_name, png_PLTE, 4))
         png_handle_PLTE(png_ptr, info_ptr, length);
#ifdef PNG_READ_bKGD_SUPPORTED
      else if (!png_memcmp(chunk_name, png_bKGD, 4))
         png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
      else if (!png_memcmp(chunk_name, png_cHRM, 4))
         png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
      else if (!png_memcmp(chunk_name, png_gAMA, 4))
         png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_hIST_SUPPORTED
      else if (!png_memcmp(chunk_name, png_hIST, 4))
         png_handle_hIST(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
      else if (!png_memcmp(chunk_name, png_oFFs, 4))
         png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
      else if (!png_memcmp(chunk_name, png_pCAL, 4))
         png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sCAL, 4))
         png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
      else if (!png_memcmp(chunk_name, png_pHYs, 4))
         png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sBIT, 4))
         png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sRGB, 4))
         png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
      else if (!png_memcmp(chunk_name, png_iCCP, 4))
         png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
      else if (!png_memcmp(chunk_name, png_sPLT, 4))
         png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tEXt, 4))
         png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tIME_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tIME, 4))
         png_handle_tIME(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
      else if (!png_memcmp(chunk_name, png_tRNS, 4))
         png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_zTXt, 4))
         png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
      else if (!png_memcmp(chunk_name, png_iTXt, 4))
         png_handle_iTXt(png_ptr, info_ptr, length);
#endif
      else
         png_handle_unknown(png_ptr, info_ptr, length);
   } while (!(png_ptr->mode & PNG_HAVE_IEND));
}
Esempio n. 3
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void /* PRIVATE */
png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
{
#ifdef PNG_USE_LOCAL_ARRAYS
      PNG_CONST PNG_IHDR;
      PNG_CONST PNG_IDAT;
      PNG_CONST PNG_IEND;
      PNG_CONST PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
      PNG_CONST PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
      PNG_CONST PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
      PNG_CONST PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
      PNG_CONST PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
      PNG_CONST PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
      PNG_CONST PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
      PNG_CONST PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
      PNG_CONST PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
      PNG_CONST PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
      PNG_CONST PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
      PNG_CONST PNG_sCAL;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
      PNG_CONST PNG_sRGB;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
      PNG_CONST PNG_sPLT;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
      PNG_CONST PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
      PNG_CONST PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
      PNG_CONST PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
      PNG_CONST PNG_zTXt;
#endif
#endif /* PNG_USE_LOCAL_ARRAYS */
   /* First we make sure we have enough data for the 4 byte chunk name
    * and the 4 byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
    * sure we have enough data in the buffer for the 4 byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
   {
      png_byte chunk_length[4];

      if (png_ptr->buffer_size < 8)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
      png_reset_crc(png_ptr);
      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
   }

   if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
     if(png_ptr->mode & PNG_AFTER_IDAT)
        png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

   if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }
   else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
      png_push_have_end(png_ptr, info_ptr);
   }
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
         png_ptr->mode |= PNG_HAVE_IDAT;
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
      if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
         png_ptr->mode |= PNG_HAVE_PLTE;
      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
      {
         if (!(png_ptr->mode & PNG_HAVE_IHDR))
            png_error(png_ptr, "Missing IHDR before IDAT");
         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                  !(png_ptr->mode & PNG_HAVE_PLTE))
            png_error(png_ptr, "Missing PLTE before IDAT");
      }
   }
#endif
   else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }
   else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
   {
      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
     if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before IDAT");
     else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
         !(png_ptr->mode & PNG_HAVE_PLTE))
       png_error(png_ptr, "Missing PLTE before IDAT");

      if (png_ptr->mode & PNG_HAVE_IDAT)
      {
         if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
           if (png_ptr->push_length == 0)
              return;

         if (png_ptr->mode & PNG_AFTER_IDAT)
            png_error(png_ptr, "Too many IDAT's found");
      }

      png_ptr->idat_size = png_ptr->push_length;
      png_ptr->mode |= PNG_HAVE_IDAT;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;
      png_push_have_info(png_ptr, info_ptr);
      png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
      png_ptr->zstream.next_out = png_ptr->row_buf;
      return;
   }
#if defined(PNG_READ_gAMA_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_bKGD_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
   else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif
   else
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
   }

   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}
Esempio n. 4
0
/* Read the information before the actual image data.  This has been
 * changed in v0.90 to allow reading a file that already has the magic
 * bytes read from the stream.  You can tell libpng how many bytes have
 * been read from the beginning of the stream (up to the maximum of 8)
 * via png_set_sig_bytes(), and we will only check the remaining bytes
 * here.  The application can then have access to the signature bytes we
 * read if it is determined that this isn't a valid PNG file.
 */
void PNGAPI
png_read_info(png_structp png_ptr, png_infop info_ptr)
{
   if(png_ptr == NULL) return;
   png_debug(1, "in png_read_info\n");
   /* If we haven't checked all of the PNG signature bytes, do so now. */
   if (png_ptr->sig_bytes < 8)
   {
      png_size_t num_checked = png_ptr->sig_bytes,
                 num_to_check = 8 - num_checked;

      png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
      png_ptr->sig_bytes = 8;

      if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
      {
         if (num_checked < 4 &&
             png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
            png_error(png_ptr, "Not a PNG file");
         else
            png_error(png_ptr, "PNG file corrupted by ASCII conversion");
      }
      if (num_checked < 3)
         png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
   }

   for(;;)
   {
#ifdef PNG_USE_LOCAL_ARRAYS
      PNG_CONST PNG_IHDR;
      PNG_CONST PNG_IDAT;
      PNG_CONST PNG_IEND;
      PNG_CONST PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
      PNG_CONST PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
      PNG_CONST PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
      PNG_CONST PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
      PNG_CONST PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
      PNG_CONST PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
      PNG_CONST PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
      PNG_CONST PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
      PNG_CONST PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
      PNG_CONST PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
      PNG_CONST PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
      PNG_CONST PNG_sCAL;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
      PNG_CONST PNG_sPLT;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
      PNG_CONST PNG_sRGB;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
      PNG_CONST PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
      PNG_CONST PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
      PNG_CONST PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
      PNG_CONST PNG_zTXt;
#endif
#endif /* PNG_USE_LOCAL_ARRAYS */
      png_byte chunk_length[4];
      png_uint_32 length;

      png_read_data(png_ptr, chunk_length, 4);
      length = png_get_uint_31(png_ptr,chunk_length);

      png_reset_crc(png_ptr);
      png_crc_read(png_ptr, png_ptr->chunk_name, 4);

      png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
         length);

      /* This should be a binary subdivision search or a hash for
       * matching the chunk name rather than a linear search.
       */
      if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
        if(png_ptr->mode & PNG_AFTER_IDAT)
          png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
         png_handle_IHDR(png_ptr, info_ptr, length);
      else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
         png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
      else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
      {
         if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
            png_ptr->mode |= PNG_HAVE_IDAT;
         png_handle_unknown(png_ptr, info_ptr, length);
         if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
            png_ptr->mode |= PNG_HAVE_PLTE;
         else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
         {
            if (!(png_ptr->mode & PNG_HAVE_IHDR))
               png_error(png_ptr, "Missing IHDR before IDAT");
            else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                     !(png_ptr->mode & PNG_HAVE_PLTE))
               png_error(png_ptr, "Missing PLTE before IDAT");
            break;
         }
      }
#endif
      else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
         png_handle_PLTE(png_ptr, info_ptr, length);
      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
      {
         if (!(png_ptr->mode & PNG_HAVE_IHDR))
            png_error(png_ptr, "Missing IHDR before IDAT");
         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                  !(png_ptr->mode & PNG_HAVE_PLTE))
            png_error(png_ptr, "Missing PLTE before IDAT");

         png_ptr->idat_size = length;
         png_ptr->mode |= PNG_HAVE_IDAT;
         break;
      }
#if defined(PNG_READ_bKGD_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
         png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
         png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
         png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
         png_handle_hIST(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
         png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
         png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
         png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
         png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
         png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
         png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
         png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
         png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
         png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
         png_handle_tIME(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
         png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
         png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
         png_handle_iTXt(png_ptr, info_ptr, length);
#endif
      else
         png_handle_unknown(png_ptr, info_ptr, length);
   }
}
Esempio n. 5
0
/* Read the end of the PNG file.  Will not read past the end of the
 * file, will verify the end is accurate, and will read any comments
 * or time information at the end of the file, if info is not NULL.
 */
void PNGAPI
png_read_end(png_structp png_ptr, png_infop info_ptr)
{
   png_byte chunk_length[4];
   png_uint_32 length;

   png_debug(1, "in png_read_end\n");
   png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */

   do
   {
#ifdef PNG_USE_LOCAL_ARRAYS
      PNG_IHDR;
      PNG_IDAT;
      PNG_IEND;
      PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
      PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
      PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
      PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
      PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
      PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
      PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
      PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
      PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
      PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
      PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
      PNG_sCAL;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
      PNG_sPLT;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
      PNG_sRGB;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
      PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
      PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
      PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
      PNG_zTXt;
#endif
#endif /* PNG_USE_LOCAL_ARRAYS */

      png_read_data(png_ptr, chunk_length, 4);
      length = png_get_uint_31(png_ptr,chunk_length);

      png_reset_crc(png_ptr);
      png_crc_read(png_ptr, png_ptr->chunk_name, 4);

      png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);

      if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
         png_handle_IHDR(png_ptr, info_ptr, length);
      else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
         png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
      else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
      {
         if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
         {
            if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
               png_error(png_ptr, "Too many IDAT's found");
         }
         else
            png_ptr->mode |= PNG_AFTER_IDAT;
         png_handle_unknown(png_ptr, info_ptr, length);
         if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
            png_ptr->mode |= PNG_HAVE_PLTE;
      }
#endif
      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
      {
         /* Zero length IDATs are legal after the last IDAT has been
          * read, but not after other chunks have been read.
          */
         if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
            png_error(png_ptr, "Too many IDAT's found");
         png_crc_finish(png_ptr, length);
      }
      else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
         png_handle_PLTE(png_ptr, info_ptr, length);
#if defined(PNG_READ_bKGD_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
         png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
         png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
         png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
         png_handle_hIST(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
         png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
         png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
         png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
         png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
         png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
         png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
         png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
         png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
         png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
         png_handle_tIME(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
         png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
         png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
      else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
         png_handle_iTXt(png_ptr, info_ptr, length);
#endif
      else
         png_handle_unknown(png_ptr, info_ptr, length);
   } while (!(png_ptr->mode & PNG_HAVE_IEND));
}
Esempio n. 6
0
void /* PRIVATE */
png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
{
   png_uint_32 chunk_name;
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   int keep; /* unknown handling method */
#endif

   /* First we make sure we have enough data for the 4-byte chunk name
    * and the 4-byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
    * sure we have enough data in the buffer for the 4-byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
      png_crc_read(png_ptr, chunk_tag, 4);
      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
   }

   chunk_name = png_ptr->chunk_name;

   if (chunk_name == png_IDAT)
   {
      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
         png_error(png_ptr, "Missing IHDR before IDAT");

      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
         png_error(png_ptr, "Missing PLTE before IDAT");

      png_ptr->mode |= PNG_HAVE_IDAT;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;

      if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
         if (png_ptr->push_length == 0)
            return;

      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_benign_error(png_ptr, "Too many IDATs found");
   }

   if (chunk_name == png_IHDR)
   {
      if (png_ptr->push_length != 13)
         png_error(png_ptr, "Invalid IHDR length");

      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IEND)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
      png_push_have_end(png_ptr, info_ptr);
   }

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);

      if (chunk_name == png_PLTE)
         png_ptr->mode |= PNG_HAVE_PLTE;
   }
#endif

   else if (chunk_name == png_PLTE)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IDAT)
   {
      png_ptr->idat_size = png_ptr->push_length;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;
      png_push_have_info(png_ptr, info_ptr);
      png_ptr->zstream.avail_out =
          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
          png_ptr->iwidth) + 1;
      png_ptr->zstream.next_out = png_ptr->row_buf;
      return;
   }

#ifdef PNG_READ_gAMA_SUPPORTED
   else if (png_ptr->chunk_name == png_gAMA)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sBIT_SUPPORTED
   else if (png_ptr->chunk_name == png_sBIT)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_cHRM_SUPPORTED
   else if (png_ptr->chunk_name == png_cHRM)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sRGB_SUPPORTED
   else if (chunk_name == png_sRGB)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_iCCP_SUPPORTED
   else if (png_ptr->chunk_name == png_iCCP)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sPLT_SUPPORTED
   else if (chunk_name == png_sPLT)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tRNS_SUPPORTED
   else if (chunk_name == png_tRNS)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_bKGD_SUPPORTED
   else if (chunk_name == png_bKGD)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_hIST_SUPPORTED
   else if (chunk_name == png_hIST)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_pHYs_SUPPORTED
   else if (chunk_name == png_pHYs)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_oFFs_SUPPORTED
   else if (chunk_name == png_oFFs)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif

#ifdef PNG_READ_pCAL_SUPPORTED
   else if (chunk_name == png_pCAL)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sCAL_SUPPORTED
   else if (chunk_name == png_sCAL)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tIME_SUPPORTED
   else if (chunk_name == png_tIME)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tEXt_SUPPORTED
   else if (chunk_name == png_tEXt)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_zTXt_SUPPORTED
   else if (chunk_name == png_zTXt)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_iTXt_SUPPORTED
   else if (chunk_name == png_iTXt)
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif

   else
   {
      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
         PNG_HANDLE_CHUNK_AS_DEFAULT);
   }

   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}
Esempio n. 7
0
void /* PRIVATE */
png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
{
   png_uint_32 chunk_name;
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   int keep; /* unknown handling method */
#endif

   /* First we make sure we have enough data for the 4 byte chunk name
    * and the 4 byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
    * sure we have enough data in the buffer for the 4 byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      if (png_ptr->buffer_size < 8)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
      png_crc_read(png_ptr, chunk_tag, 4);
      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
   }

   chunk_name = png_ptr->chunk_name;

#ifdef PNG_READ_APNG_SUPPORTED
   if (png_ptr->num_frames_read > 0 &&
       png_ptr->num_frames_read < info_ptr->num_frames)
   {
      if (chunk_name == png_IDAT)
      {
         /* Discard trailing IDATs for the first frame */
         if (png_ptr->mode & PNG_HAVE_fcTL || png_ptr->num_frames_read > 1)
            png_error(png_ptr, "out of place IDAT");

         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
         {
            png_push_save_buffer(png_ptr);
            return;
         }

         png_push_crc_skip(png_ptr, png_ptr->push_length);
         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
         return;
      }
      else if (chunk_name == png_fdAT)
      {
         if (png_ptr->buffer_size < 4)
         {
            png_push_save_buffer(png_ptr);
            return;
         }

         png_ensure_sequence_number(png_ptr, 4);

         if (!(png_ptr->mode & PNG_HAVE_fcTL))
         {
            /* Discard trailing fdATs for frames other than the first */
            if (png_ptr->num_frames_read < 2)
               png_error(png_ptr, "out of place fdAT");

            if (png_ptr->push_length + 4 > png_ptr->buffer_size)
            {
               png_push_save_buffer(png_ptr);
               return;
            }

            png_push_crc_skip(png_ptr, png_ptr->push_length);
            png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
            return;
         }

         else
         {
            /* frame data follows */
            png_ptr->idat_size = png_ptr->push_length - 4;
            png_ptr->mode |= PNG_HAVE_IDAT;
            png_ptr->process_mode = PNG_READ_IDAT_MODE;

            return;
         }
      }

      else if (chunk_name == png_fcTL)
      {
         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
         {
            png_push_save_buffer(png_ptr);
            return;
         }

         png_read_reset(png_ptr);
         png_ptr->mode &= ~PNG_HAVE_fcTL;

         png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);

         if (!(png_ptr->mode & PNG_HAVE_fcTL))
            png_error(png_ptr, "missing required fcTL chunk");

         png_read_reinit(png_ptr, info_ptr);
         png_progressive_read_reset(png_ptr);

         if (png_ptr->frame_info_fn != NULL)
            (*(png_ptr->frame_info_fn))(png_ptr, png_ptr->num_frames_read);

         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;

         return;
      }

      else
      {
         if (png_ptr->push_length + 4 > png_ptr->buffer_size)
         {
            png_push_save_buffer(png_ptr);
            return;
         }
         png_warning(png_ptr, "Skipped (ignored) a chunk "
                              "between APNG chunks");
         png_push_crc_skip(png_ptr, png_ptr->push_length);
         png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
         return;
      }

      return;
   }
#endif /* PNG_READ_APNG_SUPPORTED */

   if (chunk_name == png_IDAT)
   {
      if (png_ptr->mode & PNG_AFTER_IDAT)
         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
      if (!(png_ptr->mode & PNG_HAVE_IHDR))
         png_error(png_ptr, "Missing IHDR before IDAT");

      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
          !(png_ptr->mode & PNG_HAVE_PLTE))
         png_error(png_ptr, "Missing PLTE before IDAT");

      png_ptr->mode |= PNG_HAVE_IDAT;

      if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
         if (png_ptr->push_length == 0)
            return;

      if (png_ptr->mode & PNG_AFTER_IDAT)
         png_benign_error(png_ptr, "Too many IDATs found");
   }

   if (chunk_name == png_IHDR)
   {
      if (png_ptr->push_length != 13)
         png_error(png_ptr, "Invalid IHDR length");

      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IEND)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
      png_push_have_end(png_ptr, info_ptr);
   }

#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);

      if (chunk_name == png_PLTE)
         png_ptr->mode |= PNG_HAVE_PLTE;
   }

#endif
   else if (chunk_name == png_PLTE)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IDAT)
   {
#ifdef PNG_READ_APNG_SUPPORTED
      png_have_info(png_ptr, info_ptr);
#endif
      png_ptr->idat_size = png_ptr->push_length;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;
      png_push_have_info(png_ptr, info_ptr);
      png_ptr->zstream.avail_out =
          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
          png_ptr->iwidth) + 1;
      png_ptr->zstream.next_out = png_ptr->row_buf;
      return;
   }

#ifdef PNG_READ_gAMA_SUPPORTED
   else if (png_ptr->chunk_name == png_gAMA)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sBIT_SUPPORTED
   else if (png_ptr->chunk_name == png_sBIT)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_cHRM_SUPPORTED
   else if (png_ptr->chunk_name == png_cHRM)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sRGB_SUPPORTED
   else if (chunk_name == png_sRGB)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_iCCP_SUPPORTED
   else if (png_ptr->chunk_name == png_iCCP)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sPLT_SUPPORTED
   else if (chunk_name == png_sPLT)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tRNS_SUPPORTED
   else if (chunk_name == png_tRNS)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_bKGD_SUPPORTED
   else if (chunk_name == png_bKGD)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_hIST_SUPPORTED
   else if (chunk_name == png_hIST)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_pHYs_SUPPORTED
   else if (chunk_name == png_pHYs)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_oFFs_SUPPORTED
   else if (chunk_name == png_oFFs)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif

#ifdef PNG_READ_pCAL_SUPPORTED
   else if (chunk_name == png_pCAL)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_sCAL_SUPPORTED
   else if (chunk_name == png_sCAL)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tIME_SUPPORTED
   else if (chunk_name == png_tIME)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_tEXt_SUPPORTED
   else if (chunk_name == png_tEXt)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_zTXt_SUPPORTED
   else if (chunk_name == png_zTXt)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_iTXt_SUPPORTED
   else if (chunk_name == png_iTXt)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

#endif
#ifdef PNG_READ_APNG_SUPPORTED
   else if (chunk_name == png_acTL)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_acTL(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_fcTL)
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }

      png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
   }
#endif /* PNG_READ_APNG_SUPPORTED */

   else
   {
      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
      {
         png_push_save_buffer(png_ptr);
         return;
      }
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
         PNG_HANDLE_CHUNK_AS_DEFAULT);
   }

   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}