MFV: r323381

Permit a deflateParams() parameter change as soon as possible.

This change fixes compression errors seen when the embedded Tomcat
web server of a UniFi Controller zlib compresses responses. Given
that Tomcat just uses Java/OpenJDK which in turn employs zlib for
its compression/decompression support, this bug might very well
affect other applications, too.

PR:	222136
This commit is contained in:
Marius Strobl 2017-09-10 01:25:15 +00:00
commit f47cbbee8a
2 changed files with 9 additions and 8 deletions

View File

@ -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) {

View File

@ -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