From 5dbed7d9ca1bbd6efcf00bb2bab56ae0d86d6e1f Mon Sep 17 00:00:00 2001
From: eliang <eliang.cs@gmail.com>
Date: Thu, 19 Dec 2013 00:52:04 +0800
Subject: [PATCH] Add support for UTF-16.

---
 index.js       | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++
 test/buffer.js | 18 ++++++++++
 2 files changed, 107 insertions(+)

diff --git a/index.js b/index.js
index ce7e854..ecddf51 100644
--- a/index.js
+++ b/index.js
@@ -143,6 +143,14 @@ Buffer.byteLength = function (str, encoding) {
     case 'base64':
       return base64ToBytes(str).length
 
+    case 'ucs2':
+    case 'ucs-2':
+    case 'utf16le':
+    case 'utf-16le':
+    case 'utf16be':
+    case 'utf-16be':
+      return str.length * 2
+
     default:
       throw new Error('Unknown encoding')
   }
@@ -232,6 +240,21 @@ function _base64Write (buf, string, offset, length) {
   return Buffer._charsWritten = blitBuffer(base64ToBytes(string), buf, offset, length)
 }
 
+function _utf16leWrite (buf, string, offset, length) {
+  var bytes, pos
+  return Buffer._charsWritten = blitBuffer(utf16leToBytes(string), buf, offset, length)
+}
+
+function _utf16leWrite (buf, string, offset, length) {
+  var bytes, pos
+  return Buffer._charsWritten = blitBuffer(utf16leToBytes(string), buf, offset, length)
+}
+
+function _utf16beWrite (buf, string, offset, length) {
+  var bytes, pos
+  return Buffer._charsWritten = blitBuffer(utf16beToBytes(string), buf, offset, length)
+}
+
 function BufferWrite (string, offset, length, encoding) {
   // Support both (string, offset, length, encoding)
   // and the legacy (string, encoding, offset, length)
@@ -276,6 +299,16 @@ function BufferWrite (string, offset, length, encoding) {
     case 'base64':
       return _base64Write(this, string, offset, length)
 
+    case 'ucs2':
+    case 'ucs-2':
+    case 'utf16le':
+    case 'utf-16le':
+      return _utf16leWrite(this, string, offset, length)
+
+    case 'utf16be':
+    case 'utf-16be':
+      return _utf16beWrite(this, string, offset, length)
+
     default:
       throw new Error('Unknown encoding')
   }
@@ -313,6 +346,16 @@ function BufferToString (encoding, start, end) {
     case 'base64':
       return _base64Slice(self, start, end)
 
+    case 'ucs2':
+    case 'ucs-2':
+    case 'utf16le':
+    case 'utf-16le':
+      return _utf16leSlice(self, start, end)
+
+    case 'utf16be':
+    case 'utf-16be':
+      return _utf16beSlice(self, start, end)
+
     default:
       throw new Error('Unknown encoding')
   }
@@ -406,6 +449,24 @@ function _hexSlice (buf, start, end) {
   return out
 }
 
+function _utf16leSlice (buf, start, end) {
+  var bytes = buf.slice(start, end)
+  var res = ''
+  for (var i = 0; i < bytes.length; i += 2) {
+    res += String.fromCharCode(bytes[i] + bytes[i+1] * 256)
+  }
+  return res
+}
+
+function _utf16beSlice (buf, start, end) {
+  var bytes = buf.slice(start, end)
+  var res = ''
+  for (var i = 0; i < bytes.length; i += 2) {
+    res += String.fromCharCode(bytes[i] * 256 + bytes[i+1])
+  }
+  return res
+}
+
 // TODO: add test that modifying the new buffer slice will modify memory in the
 // original buffer! Use code from:
 // http://nodejs.org/api/buffer.html#buffer_buf_slice_start_end
@@ -1090,6 +1151,34 @@ function asciiToBytes (str) {
   return byteArray
 }
 
+function utf16leToBytes (str) {
+  var c, hi, lo
+  var byteArray = []
+  for (var i = 0; i < str.length; i++) {
+    c = str.charCodeAt(i)
+    hi = c >> 8
+    lo = c % 256
+    byteArray.push(lo)
+    byteArray.push(hi)
+  }
+
+  return byteArray
+}
+
+function utf16beToBytes (str) {
+  var c, hi, lo
+  var byteArray = []
+  for (var i = 0; i < str.length; i++) {
+    c = str.charCodeAt(i)
+    hi = c >> 8
+    lo = c % 256
+    byteArray.push(hi)
+    byteArray.push(lo)
+  }
+
+  return byteArray
+}
+
 function base64ToBytes (str) {
   return base64.toByteArray(str)
 }
diff --git a/test/buffer.js b/test/buffer.js
index 0d8ff7b..dfab08c 100644
--- a/test/buffer.js
+++ b/test/buffer.js
@@ -28,6 +28,24 @@ test('utf8 to utf8', function (t) {
     t.end();
 });
 
+test('utf16be to hexutf16', function (t) {
+    t.plan(1);
+    t.equal(
+        new B("abcd", "utf16be").toString('hex'),
+        '0061006200630064'
+    );
+    t.end();
+});
+
+test('utf16le to hex', function (t) {
+    t.plan(1);
+    t.equal(
+        new B("abcd", "utf16le").toString('hex'),
+        '6100620063006400'
+    );
+    t.end();
+});
+
 test('ascii buffer to base64', function (t) {
     t.plan(1);
     t.equal(
-- 
2.34.1