Permit immediate deflateParams changes before any deflate input.

This permits deflateParams to change the strategy and level right
after deflateInit, without having to wait until a header has been
written. The parameters can be changed immediately up until the
first deflate call that consumes any input data.

1 files changed, 5 insertions, 4 deletions

diff --git a/zlib.h b/zlib.h
index ab0b41d..119b392 100644
--- a/zlib.h
+++ b/zlib.h
@@ -704,10 +704,11 @@ 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, 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 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().
 
      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