From b57a8abd59fb6eb85c075771be921c7a2379035c Mon Sep 17 00:00:00 2001
From: Huan Du <i@huandu.me>
Date: Thu, 8 Jan 2015 20:58:13 +0800
Subject: [PATCH] refs #7. reverse string.

---
 manipulate.go      | 26 ++++++++++++++++++++++++++
 manipulate_test.go | 16 ++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 manipulate.go
 create mode 100644 manipulate_test.go

diff --git a/manipulate.go b/manipulate.go
new file mode 100644
index 0000000..86bfcae
--- /dev/null
+++ b/manipulate.go
@@ -0,0 +1,26 @@
+// Copyright 2015 Huan Du. All rights reserved.
+// Licensed under the MIT license that can be found in the LICENSE file.
+
+package xstrings
+
+import (
+	"unicode/utf8"
+)
+
+// Reverse a utf8 encoded string.
+func Reverse(str string) string {
+	var size int
+
+	tail := len(str)
+	buf := make([]byte, tail)
+	s := buf
+
+	for len(str) > 0 {
+		_, size = utf8.DecodeRuneInString(str)
+		tail -= size
+		s = append(s[:tail], []byte(str[:size])...)
+		str = str[size:]
+	}
+
+	return string(buf)
+}
diff --git a/manipulate_test.go b/manipulate_test.go
new file mode 100644
index 0000000..6f109db
--- /dev/null
+++ b/manipulate_test.go
@@ -0,0 +1,16 @@
+// Copyright 2015 Huan Du. All rights reserved.
+// Licensed under the MIT license that can be found in the LICENSE file.
+
+package xstrings
+
+import (
+	"testing"
+)
+
+func TestReverse(t *testing.T) {
+	runTestCases(t, Reverse, map[string]string{
+		"reverse string": "gnirts esrever",
+		"中文如何？":          "？何如文中",
+		"中en文混~排怎样？a":    "a？样怎排~混文ne中",
+	})
+}