From: Nathan Moinvaziri <nathan@nathanm.com>
Date: Tue, 15 Jun 2021 00:42:24 +0000 (-0700)
Subject: Minor prev_length calculation improvement in deflate_slow.
X-Git-Tag: 2.1.0-beta1~547
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8543ecaa4824994827708d3e5684777eaeb4cfc;p=thirdparty%2Fzlib-ng.git

Minor prev_length calculation improvement in deflate_slow.
---

diff --git a/deflate_slow.c b/deflate_slow.c
index a3af11bcf..e0232c0a1 100644
--- a/deflate_slow.c
+++ b/deflate_slow.c
@@ -81,9 +81,10 @@ Z_INTERNAL block_state deflate_slow(deflate_state *s, int flush) {
              * enough lookahead, the last two strings are not inserted in
              * the hash table.
              */
-            s->lookahead -= s->prev_length-1;
+            s->prev_length -= 1;
+            s->lookahead -= s->prev_length;
 
-            unsigned int mov_fwd = s->prev_length - 2;
+            unsigned int mov_fwd = s->prev_length - 1;
             if (max_insert > s->strstart) {
                 unsigned int insert_cnt = mov_fwd;
                 if (UNLIKELY(insert_cnt > max_insert - s->strstart))