From: Mark Adler <madler@alumni.caltech.edu>
Date: Mon, 16 Jan 2017 17:49:35 +0000 (-0800)
Subject: Permit a deflateParams() parameter change as soon as possible.
X-Git-Tag: 1.9.9-b1~564
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11413c0618ff9209639775a22bb7dbe492ef4b65;p=thirdparty%2Fzlib-ng.git

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.
---

diff --git a/deflate.c b/deflate.c
index 64d870f0..fc48a31d 100644
--- a/deflate.c
+++ b/deflate.c
@@ -510,7 +510,7 @@ int ZEXPORT PREFIX(deflateResetKeep)(PREFIX3(stream) *strm) {
     else
 #endif
         strm->adler = functable.adler32(0L, NULL, 0);
-    s->last_flush = Z_NO_FLUSH;
+    s->last_flush = -2;
 
     _tr_init(s);
 
@@ -586,12 +586,13 @@ int ZEXPORT PREFIX(deflateParams)(PREFIX3(stream) *strm, int level, int strategy
     }
     func = configuration_table[s->level].func;
 
-    if ((strategy != s->strategy || func != configuration_table[level].func) && s->high_water) {
+    if ((strategy != s->strategy || func != configuration_table[level].func) &&
+        s->last_flush != -2) {
         /* Flush the last buffer: */
         int err = PREFIX(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-ng.h b/zlib-ng.h
index 3a52d1f2..3d972a0c 100644
--- a/zlib-ng.h
+++ b/zlib-ng.h
@@ -693,11 +693,12 @@ ZEXTERN int ZEXPORT zng_deflateParams(zng_stream *strm, int level, int strategy)
    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
diff --git a/zlib.h b/zlib.h
index afe71ea1..89135001 100644
--- a/zlib.h
+++ b/zlib.h
@@ -704,11 +704,12 @@ ZEXTERN int ZEXPORT deflateParams(z_stream *strm, int level, int strategy);
    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