[devel] IDAT compression failed if preceded by a compressed text chunk

This was because the attempt to reset the zlib stream in png_write_IDAT
happened after the first IDAT chunk had been deflated - much too late.
In this change internal functions are added to claim/release the z_stream
and, hopefully, make the code more robust.  Also deflateEnd checking is
added - previously libpng would ignore an error at the end of the stream.
This commit is contained in:
John Bowler
2011-05-05 17:35:39 -05:00
committed by Glenn Randers-Pehrson
parent c559bb58ed
commit c5bef946b1
9 changed files with 203 additions and 104 deletions

2
png.h
View File

@@ -1394,6 +1394,7 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
#ifdef PNG_WRITE_SUPPORTED
/* Set the library compression level. Currently, valid values range from
* 0 - 9, corresponding directly to the zlib compression levels 0 - 9
* (0 - no compression, 9 - "maximal" compression). Note that tests have
@@ -1415,6 +1416,7 @@ PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structp png_ptr,
PNG_EXPORT(73, void, png_set_compression_method, (png_structp png_ptr,
int method));
#endif
#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
/* Also set zlib parameters for compressing non-IDAT chunks */