From 22ae39a8c3d25f512605806646e166d6a87e0eb2 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Wed, 3 Aug 2011 11:59:19 -0500
Subject: [PATCH] Faster 1.8 codepoint encoder

---
 lib/execjs/external_runtime.rb | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/execjs/external_runtime.rb b/lib/execjs/external_runtime.rb
index bf58b0a..f3257ce 100644
--- a/lib/execjs/external_runtime.rb
+++ b/lib/execjs/external_runtime.rb
@@ -74,9 +74,11 @@ def encode_unicode_codepoints(str)
           end
         else
           def encode_unicode_codepoints(str)
-            str.unpack("U*").map { |b|
-              b >= 128 ? "\\u%04x" % b : b.chr
-            }.join("")
+            str.gsub(/([\xC0-\xDF][\x80-\xBF]|
+                       [\xE0-\xEF][\x80-\xBF]{2}|
+                       [\xF0-\xF7][\x80-\xBF]{3})+/nx) do |ch|
+              "\\u%04x" % ch.unpack("U*")
+            end
           end
         end
     end