From ab4f92b809f69e5aa438deb842e017752d981bc8 Mon Sep 17 00:00:00 2001 From: Marius Strobl Date: Sun, 10 Sep 2017 00:56:28 +0000 Subject: [PATCH] Permit a deflateParams() parameter change as soon as possible. This commit allows a parameter change even if the input data has not all been compressed and copied to the application output buffer, so long as all of the input data has been compressed to the internal pending output buffer. This also allows an immediate deflateParams change so long as there have been no deflate calls since initialization or reset. Obtained from: upstream (f9694097dd69354b03cb8af959094c7f260db0a1) --- deflate.c | 6 +++--- zlib.h | 11 ++++++----- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/deflate.c b/deflate.c index 1ec761448de..7f2c8a2a2a6 100644 --- a/deflate.c +++ b/deflate.c @@ -494,7 +494,7 @@ int ZEXPORT deflateResetKeep (strm) s->wrap == 2 ? crc32(0L, Z_NULL, 0) : #endif adler32(0L, Z_NULL, 0); - s->last_flush = Z_NO_FLUSH; + s->last_flush = -2; _tr_init(s); @@ -587,12 +587,12 @@ int ZEXPORT deflateParams(strm, level, strategy) func = configuration_table[s->level].func; if ((strategy != s->strategy || func != configuration_table[level].func) && - s->high_water) { + s->last_flush != -2) { /* Flush the last buffer: */ int err = deflate(strm, Z_BLOCK); if (err == Z_STREAM_ERROR) return err; - if (strm->avail_out == 0) + if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead) return Z_BUF_ERROR; } if (s->level != level) { diff --git a/zlib.h b/zlib.h index f09cdaf1e05..001624e5ed8 100644 --- a/zlib.h +++ b/zlib.h @@ -712,11 +712,12 @@ ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, used to switch between compression and straight copy of the input data, or to switch to a different kind of input data requiring a different strategy. If the compression approach (which is a function of the level) or the - strategy is changed, and if any input has been consumed in a previous - deflate() call, then the input available so far is compressed with the old - level and strategy using deflate(strm, Z_BLOCK). There are three approaches - for the compression levels 0, 1..3, and 4..9 respectively. The new level - and strategy will take effect at the next call of deflate(). + strategy is changed, and if there have been any deflate() calls since the + state was initialized or reset, then the input available so far is + compressed with the old level and strategy using deflate(strm, Z_BLOCK). + There are three approaches for the compression levels 0, 1..3, and 4..9 + respectively. The new level and strategy will take effect at the next call + of deflate(). If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does not have enough output space to complete, then the parameter change will not