diff options
author | John Bowler <jbowler@acm.org> | 2012-08-15 22:53:00 -0500 |
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committer | Glenn Randers-Pehrson <glennrp at users.sourceforge.net> | 2012-08-15 22:53:00 -0500 |
commit | e9567514dd42a4a756def1f21d3b52ea83966777 (patch) | |
tree | 3483dc7bbcccef34253fae94a0b6439988d4e591 /pngpread.c | |
parent | b593b3f0353fa039fc73347d1e63210538034a88 (diff) | |
download | libpng-e9567514dd42a4a756def1f21d3b52ea83966777.tar.gz |
[libpng16] Unknown handling fixes and clean up. This adds more correct option
control of the unknown handling, corrects the pre-existing bug where
the per-chunk 'keep' setting is ignored and makes it possible to skip
IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
There is a new test program, test-unknown.c, which is a work in progress
(not currently part of the test suite). Comments in the header files now
explain how the unknown handling works.
Diffstat (limited to 'pngpread.c')
-rw-r--r-- | pngpread.c | 72 |
1 files changed, 27 insertions, 45 deletions
diff --git a/pngpread.c b/pngpread.c index 608eda10b..2da3dfe3c 100644 --- a/pngpread.c +++ b/pngpread.c @@ -185,6 +185,9 @@ 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 @@ -216,14 +219,28 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) if (chunk_name == png_IDAT) { - /* This is here above the if/else case statement below because if the - * unknown handling marks 'IDAT' as unknown then the IDAT handling case is - * completely skipped. - * - * TODO: there must be a better way of doing this. - */ 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) @@ -255,7 +272,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) } #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED - else if (png_chunk_unknown_handling(png_ptr, chunk_name)) + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name))) { if (png_ptr->push_length + 4 > png_ptr->buffer_size) { @@ -263,23 +280,10 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) return; } - if (chunk_name == png_IDAT) - png_ptr->mode |= PNG_HAVE_IDAT; - - png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); + png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep); if (chunk_name == png_PLTE) png_ptr->mode |= PNG_HAVE_PLTE; - - else if (chunk_name == png_IDAT) - { - 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 @@ -295,30 +299,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) else if (chunk_name == png_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"); - - 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_benign_error(png_ptr, "Too many IDATs 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 = @@ -556,7 +537,8 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) png_push_save_buffer(png_ptr); return; } - png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); + png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, + PNG_HANDLE_CHUNK_AS_DEFAULT); } png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; |