-void /* PRIVATE */
-png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
-{
- png_ptr->process_mode = PNG_SKIP_MODE;
- png_ptr->skip_length = skip;
-}
-
-void /* PRIVATE */
-png_push_crc_finish(png_structrp png_ptr)
-{
- if (png_ptr->skip_length && png_ptr->save_buffer_size)
- {
- png_size_t save_size = png_ptr->save_buffer_size;
- png_uint_32 skip_length = png_ptr->skip_length;
-
- /* We want the smaller of 'skip_length' and 'save_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 or 64 bit platforms.
- */
- if (skip_length < save_size)
- save_size = (png_size_t)skip_length;
-
- else
- skip_length = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
- png_ptr->skip_length -= skip_length;
- png_ptr->buffer_size -= save_size;
- png_ptr->save_buffer_size -= save_size;
- png_ptr->save_buffer_ptr += save_size;
- }
- if (png_ptr->skip_length && png_ptr->current_buffer_size)
- {
- png_size_t save_size = png_ptr->current_buffer_size;
- png_uint_32 skip_length = png_ptr->skip_length;
-
- /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
- * the same problem exists as above and the same solution.
- */
- if (skip_length < save_size)
- save_size = (png_size_t)skip_length;
-
- else
- skip_length = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
- png_ptr->skip_length -= skip_length;
- png_ptr->buffer_size -= save_size;
- png_ptr->current_buffer_size -= save_size;
- png_ptr->current_buffer_ptr += save_size;
- }
- if (!png_ptr->skip_length)
- {
- if (png_ptr->buffer_size < 4)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_crc_finish(png_ptr, 0);
- png_ptr->process_mode = PNG_READ_CHUNK_MODE;
- }
-}
-