Added multi-byte support for string#chop

gistfile1.txt

From 2f5fa63bf565c7dcc6f3ff4808eab337f1240dff Mon Sep 17 00:00:00 2001
From: Alejandro Ciniglio <mail@alejandrociniglio.com>
Date: Wed, 5 Dec 2012 12:08:45 -0500
Subject: [PATCH] Added multi-byte support for String#chop

Added support for string19
Added spec to test under 1.9
---
 kernel/common/string19.rb          | 11 ++++++++++-
 spec/ruby/core/string/chop_spec.rb |  5 +++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/kernel/common/string19.rb b/kernel/common/string19.rb
index 9e54523..c20b41d 100644
--- a/kernel/common/string19.rb
+++ b/kernel/common/string19.rb
@@ -487,7 +487,16 @@ class String
         @data[@num_bytes-1] == 10 and @data[@num_bytes-2] == 13
       self.num_bytes -= 2
     else
-      self.num_bytes -= 1
+      if @data[@num_bytes-1] & 128 == 0
+        self.num_bytes -= 1
+      elsif @data[@num_bytes-2] & (128|64) == (128|64)
+        self.num_bytes -= 2
+      elsif @data[@num_bytes-3] & (128|64|32) == (128|64|32)
+        self.num_bytes -= 3
+      elsif @data[@num_bytes-4] & (128|64|32|16) == (128|64|32|16)
+        self.num_bytes -= 4
+      end
+
     end
 
     self
diff --git a/spec/ruby/core/string/chop_spec.rb b/spec/ruby/core/string/chop_spec.rb
index fb18eef..fa91c0d 100644
--- a/spec/ruby/core/string/chop_spec.rb
+++ b/spec/ruby/core/string/chop_spec.rb
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 require File.expand_path('../../../spec_helper', __FILE__)
 require File.expand_path('../fixtures/classes.rb', __FILE__)
 
@@ -46,6 +47,10 @@ describe "String#chop" do
       "hello".untrust.chop.untrusted?.should == true
       "".untrust.chop.untrusted?.should == true
     end
+
+    it "works with multi-byte characters" do
+      "日本語".chop.should == "日本"
+    end
   end
 
   it "returns subclass instances when called on a subclass" do
-- 
1.8.0.1