From 56d3d9851a824aeb921c9853042776866aa195a3 Mon Sep 17 00:00:00 2001
From: Hans Kristian Rosbach <hk-git@circlestorm.org>
Date: Wed, 21 Feb 2024 14:50:18 +0100
Subject: [PATCH] Clean up insert_match() in deflate_medium

---
 deflate_medium.c | 43 +++++++++++++++----------------------------
 1 file changed, 15 insertions(+), 28 deletions(-)

diff --git a/deflate_medium.c b/deflate_medium.c
index ca334e4b35..2aeebe2026 100644
--- a/deflate_medium.c
+++ b/deflate_medium.c
@@ -45,10 +45,12 @@ static void insert_match(deflate_state *s, struct match match) {
     if (UNLIKELY(s->lookahead <= (unsigned int)(match.match_length + WANT_MIN_MATCH)))
         return;
 
+    /* string at strstart already in table */
+    match.strstart++;
+    match.match_length--;
+
     /* matches that are not long enough we need to emit as literals */
-    if (LIKELY(match.match_length < WANT_MIN_MATCH)) {
-        match.strstart++;
-        match.match_length--;
+    if (LIKELY(match.match_length < WANT_MIN_MATCH - 1)) {
         if (UNLIKELY(match.match_length > 0)) {
             if (match.strstart >= match.orgstart) {
                 if (match.strstart + match.match_length - 1 >= match.orgstart) {
@@ -63,33 +65,18 @@ static void insert_match(deflate_state *s, struct match match) {
         return;
     }
 
-    /* Insert new strings in the hash table. */
-    if (s->lookahead >= WANT_MIN_MATCH) {
-        match.match_length--; /* string at strstart already in table */
-        match.strstart++;
-
-        if (LIKELY(match.strstart >= match.orgstart)) {
-            if (LIKELY(match.strstart + match.match_length - 1 >= match.orgstart)) {
-                insert_string(s, match.strstart, match.match_length);
-            } else {
-                insert_string(s, match.strstart, match.orgstart - match.strstart + 1);
-            }
-        } else if (match.orgstart < match.strstart + match.match_length) {
-            insert_string(s, match.orgstart, match.strstart + match.match_length - match.orgstart);
+    /* Insert into hash table. */
+    if (LIKELY(match.strstart >= match.orgstart)) {
+        if (LIKELY(match.strstart + match.match_length - 1 >= match.orgstart)) {
+            insert_string(s, match.strstart, match.match_length);
+        } else {
+            insert_string(s, match.strstart, match.orgstart - match.strstart + 1);
         }
-        match.strstart += match.match_length;
-        match.match_length = 0;
-    } else {
-        match.strstart += match.match_length;
-        match.match_length = 0;
-
-        if (match.strstart >= (STD_MIN_MATCH - 2))
-            quick_insert_string(s, match.strstart + 2 - STD_MIN_MATCH);
-
-        /* If lookahead < WANT_MIN_MATCH, ins_h is garbage, but it does not
-         * matter since it will be recomputed at next deflate call.
-         */
+    } else if (match.orgstart < match.strstart + match.match_length) {
+        insert_string(s, match.orgstart, match.strstart + match.match_length - match.orgstart);
     }
+    match.strstart += match.match_length;
+    match.match_length = 0;
 }
 
 static void fizzle_matches(deflate_state *s, struct match *current, struct match *next) {