Fix inconsistent handling of invalid zlib data
In libpng 1.6 zlib initialization was changed to use the window size in the zlib
stream, not a fixed value. This causes some invalid images, ones where CINFO is
too large, to display 'correctly' if the rest of the data is valid. This
provides a work-round for zlib versions where the error arises (ones that
support the API change to use the window size in the stream).
Signed-off-by: John Bowler <jbowler@acm.org>
diff --git a/pngstruct.h b/pngstruct.h
index c8c0e46..d0bcc79 100644
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -263,6 +263,9 @@
/* pixel depth used for the row buffers */
png_byte transformed_pixel_depth;
/* pixel depth after read/write transforms */
+#if PNG_ZLIB_VERNUM >= 0x1240
+ png_byte zstream_start; /* at start of an input zlib stream */
+#endif /* Zlib >= 1.2.4 */
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
png_uint_16 filler; /* filler bytes for pixel expansion */
#endif