예제 #1
0
파일: pngpread.c 프로젝트: 007Indian/opencv
void /* PRIVATE */
png_push_read_IDAT(png_structrp png_ptr)
{
   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      /* TODO: this code can be commoned up with the same code in push_read */
      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_ptr->mode |= PNG_HAVE_CHUNK_HEADER;

      if (png_ptr->chunk_name != png_IDAT)
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;

         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
            png_error(png_ptr, "Not enough compressed data");

         return;
      }

      png_ptr->idat_size = png_ptr->push_length;
   }

   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;

      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
       * are of different types and we don't know which variable has the fewest
       * bits.  Carefully select the smaller and cast it to the type of the
       * larger - this cannot overflow.  Do not cast in the following test - it
       * will break on either 16-bit or 64-bit platforms.
       */
      if (idat_size < save_size)
         save_size = (png_size_t)idat_size;

      else
         idat_size = (png_uint_32)save_size;

      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);

      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);

      png_ptr->idat_size -= idat_size;
      png_ptr->buffer_size -= save_size;
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }

   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;

      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
       * are of different types and we don't know which variable has the fewest
       * bits.  Carefully select the smaller and cast it to the type of the
       * larger - this cannot overflow.
       */
      if (idat_size < save_size)
         save_size = (png_size_t)idat_size;

      else
         idat_size = (png_uint_32)save_size;

      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);

      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);

      png_ptr->idat_size -= idat_size;
      png_ptr->buffer_size -= save_size;
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }

   if (png_ptr->idat_size == 0)
   {
      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
      png_ptr->mode |= PNG_AFTER_IDAT;
      png_ptr->zowner = 0;
   }
}
예제 #2
0
void /* PRIVATE */
png_push_read_IDAT(png_structrp png_ptr)
{
    if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
    {
        png_byte chunk_length[4];
        png_byte chunk_tag[4];

        /* TODO: this code can be commoned up with the same code in push_read */
#ifdef PNG_READ_APNG_SUPPORTED
        PNG_PUSH_SAVE_BUFFER_IF_LT(12)
#else
        PNG_PUSH_SAVE_BUFFER_IF_LT(8)
#endif
        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_ptr->mode |= PNG_HAVE_CHUNK_HEADER;

#ifdef PNG_READ_APNG_SUPPORTED
        if (png_ptr->chunk_name != png_fdAT && png_ptr->num_frames_read > 0)
        {
            if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) != 0)
            {
                png_ptr->process_mode = PNG_READ_CHUNK_MODE;
                if (png_ptr->frame_end_fn != NULL)
                    (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read);
                png_ptr->num_frames_read++;
                return;
            }
            else
            {
                if (png_ptr->chunk_name == png_IEND)
                    png_error(png_ptr, "Not enough image data");
                PNG_PUSH_SAVE_BUFFER_IF_FULL
                png_warning(png_ptr, "Skipping (ignoring) a chunk between "
                            "APNG chunks");
                png_crc_finish(png_ptr, png_ptr->push_length);
                png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
                return;
            }
        }
        else
#endif
#ifdef PNG_READ_APNG_SUPPORTED
            if (png_ptr->chunk_name != png_IDAT && png_ptr->num_frames_read == 0)
#else
            if (png_ptr->chunk_name != png_IDAT)
#endif
            {
                png_ptr->process_mode = PNG_READ_CHUNK_MODE;

                if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
                    png_error(png_ptr, "Not enough compressed data");

#ifdef PNG_READ_APNG_SUPPORTED
                if (png_ptr->frame_end_fn != NULL)
                    (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read);
                png_ptr->num_frames_read++;
#endif

                return;
            }

        png_ptr->idat_size = png_ptr->push_length;

#ifdef PNG_READ_APNG_SUPPORTED
        if (png_ptr->num_frames_read > 0)
        {
            png_ensure_sequence_number(png_ptr, 4);
            png_ptr->idat_size -= 4;
        }
#endif
    }

    if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
    {
        png_size_t save_size = png_ptr->save_buffer_size;
        png_uint_32 idat_size = png_ptr->idat_size;

        /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
         * are of different types and we don't know which variable has the fewest
         * bits.  Carefully select the smaller and cast it to the type of the
         * larger - this cannot overflow.  Do not cast in the following test - it
         * will break on either 16-bit or 64-bit platforms.
         */
        if (idat_size < save_size)
            save_size = (png_size_t)idat_size;

        else
            idat_size = (png_uint_32)save_size;

        png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);

        png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);

        png_ptr->idat_size -= idat_size;
        png_ptr->buffer_size -= save_size;
        png_ptr->save_buffer_size -= save_size;
        png_ptr->save_buffer_ptr += save_size;
    }

    if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
    {
        png_size_t save_size = png_ptr->current_buffer_size;
        png_uint_32 idat_size = png_ptr->idat_size;

        /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
         * are of different types and we don't know which variable has the fewest
         * bits.  Carefully select the smaller and cast it to the type of the
         * larger - this cannot overflow.
         */
        if (idat_size < save_size)
            save_size = (png_size_t)idat_size;

        else
            idat_size = (png_uint_32)save_size;

        png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);

        png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);

        png_ptr->idat_size -= idat_size;
        png_ptr->buffer_size -= save_size;
        png_ptr->current_buffer_size -= save_size;
        png_ptr->current_buffer_ptr += save_size;
    }

    if (png_ptr->idat_size == 0)
    {
        PNG_PUSH_SAVE_BUFFER_IF_LT(4)
        png_crc_finish(png_ptr, 0);
        png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
        png_ptr->mode |= PNG_AFTER_IDAT;
        png_ptr->zowner = 0;
    }
}
예제 #3
0
파일: pngpread.c 프로젝트: 007Indian/opencv
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;
}
예제 #4
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;
}