diff options
| -rw-r--r-- | pngrutil.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/pngrutil.c b/pngrutil.c index 381d83076..f78934807 100644 --- a/pngrutil.c +++ b/pngrutil.c @@ -236,6 +236,13 @@ png_crc_finish(png_structrp png_ptr, png_uint_32 skip) } #ifdef PNG_INDEX_SUPPORTED +/* If tile index is used to skip over data and decode a partial image + * the crc value may be incorrect. + * The crc will only be calculated for the partial data read, + * not the entire data, which will result in an incorrect crc value. + * This function treats a png_crc_error as a warning, as opposed to the + * original function png_crc_finish, which will treat it as an error. + */ int /* PRIVATE */ png_opt_crc_finish(png_structrp png_ptr, png_uint_32 skip) { @@ -4143,6 +4150,14 @@ png_read_finish_IDAT(png_structrp png_ptr) * crc_finish here. If idat_size is non-zero we also need to read the * spurious bytes at the end of the chunk now. */ +#ifdef PNG_INDEX_SUPPORTED + if (png_ptr->index) + { + (void)png_opt_crc_finish(png_ptr, png_ptr->idat_size); + png_ptr->index->stream_idat_position = png_ptr->total_data_read; + } + else +#endif (void)png_crc_finish(png_ptr, png_ptr->idat_size); } } |