From df1e22f2e4148e7a819b040f0ef4782f2db8d06c Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Fri, 30 Dec 2011 14:59:00 -0800
Subject: [PATCH] Switch to push instead of slice. Faster on jsperf, but
 doesn't seem to be faster testing locally.

---
 src/function.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/function.js b/src/function.js
index 996b62c6a..83db53ba1 100644
--- a/src/function.js
+++ b/src/function.js
@@ -437,8 +437,9 @@ var PostScriptStack = (function PostScriptStackClosure() {
     copy: function copy(n) {
       if (this.stack.length + n >= MAX_STACK_SIZE)
         error('PostScript function stack overflow.');
-      var part = this.stack.slice(this.stack.length - n);
-      this.stack = this.stack.concat(part);
+      var stack = this.stack;
+      for (var i = stack.length - n, j = n - 1; j >= 0; j--, i++)
+        stack.push(stack[i]);
     },
     index: function index(n) {
       this.push(this.stack[this.stack.length - n - 1]);