tree c9b07b2ffbe15a7f5f9b469a51993ddf45b9eb63
parent c559bb58ed25ae0d6b732283afeaabb36e4b430f
author John Bowler <jbowler@acm.org> 1304634939 -0500
committer Glenn Randers-Pehrson <glennrp at users.sourceforge.net> 1304634939 -0500

[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.