From: Nathan Moinvaziri <nathan@nathanm.com>
Date: Thu, 4 Jun 2020 18:17:04 +0000 (-0700)
Subject: Move check for hash_head != 0 directly after quick_insert_string.
X-Git-Tag: 1.9.9-b1~186
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4fbbf00ce043041e897042ebdede3e3e45379e1e;p=thirdparty%2Fzlib-ng.git

Move check for hash_head != 0 directly after quick_insert_string.
---

diff --git a/deflate_fast.c b/deflate_fast.c
index 92a091f7..3a2dc4d2 100644
--- a/deflate_fast.c
+++ b/deflate_fast.c
@@ -38,22 +38,22 @@ ZLIB_INTERNAL block_state deflate_fast(deflate_state *s, int flush) {
         /* Insert the string window[strstart .. strstart+2] in the
          * dictionary, and set hash_head to the head of the hash chain:
          */
-        hash_head = NIL;
+        s->match_length = 0;
         if (s->lookahead >= MIN_MATCH) {
             hash_head = functable.quick_insert_string(s, s->strstart);
-        }
-
-        /* Find the longest match, discarding those <= prev_length.
-         * At this point we have always match_length < MIN_MATCH
-         */
-        if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
-            /* To simplify the code, we prevent matches with the string
-             * of window index 0 (in particular we have to avoid a match
-             * of the string with itself at the start of the input file).
+            /* Find the longest match, discarding those <= prev_length.
+             * At this point we have always match_length < MIN_MATCH
              */
-            s->match_length = functable.longest_match(s, hash_head);
-            /* longest_match() sets match_start */
+            if (hash_head != 0 && s->strstart - hash_head <= MAX_DIST(s)) {
+                /* To simplify the code, we prevent matches with the string
+                 * of window index 0 (in particular we have to avoid a match
+                 * of the string with itself at the start of the input file).
+                 */
+                s->match_length = functable.longest_match(s, hash_head);
+                /* longest_match() sets match_start */
+            }
         }
+
         if (s->match_length >= MIN_MATCH) {
             check_match(s, s->strstart, s->match_start, s->match_length);