From 144d14797751e7bf4de7d1444b4122f464a39014 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Thu, 14 Dec 2017 14:26:33 +1100
Subject: src/lstrlib.js: Optimise find_subarray using .indexOf

---
 src/lstrlib.js | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

(limited to 'src')

diff --git a/src/lstrlib.js b/src/lstrlib.js
index c4dd1ae..23b0404 100644
--- a/src/lstrlib.js
+++ b/src/lstrlib.js
@@ -1148,13 +1148,20 @@ const reprepstate = function(ms) {
 
 const find_subarray = function(arr, subarr, from_index) {
     var i = from_index >>> 0,
-        sl = subarr.length,
-        l = arr.length + 1 - sl;
+        sl = subarr.length;
 
-    loop: for (; i < l; i++) {
-        for (let j = 0; j < sl; j++)
-            if (arr[i+j] !== subarr[j])
+    if (sl === 0)
+        return i;
+
+    loop: for (;;) {
+        i = arr.indexOf(subarr[0], i);
+        if (i === -1) break;
+        for (let j = 1; j < sl; j++) {
+            if (arr[i+j] !== subarr[j]) {
+                i++;
                 continue loop;
+            }
+        }
         return i;
     }
     return -1;
-- 
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