1/*!
 2 * ws: a node.js websocket client
 3 * Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
 4 * MIT Licensed
 5 */
 6
 7module.exports.BufferUtil = {
 8  merge: function(mergedBuffer, buffers) {
 9    var offset = 0;
10    for (var i = 0, l = buffers.length; i < l; ++i) {
11      var buf = buffers[i];
12      buf.copy(mergedBuffer, offset);
13      offset += buf.length;
14    }
15  },
16  mask: function(source, mask, output, offset, length) {
17    var maskNum = mask.readUInt32LE(0, true);
18    var i = 0;
19    for (; i < length - 3; i += 4) {
20      var num = maskNum ^ source.readUInt32LE(i, true);
21      if (num < 0) num = 4294967296 + num;
22      output.writeUInt32LE(num, offset + i, true);
23    }
24    switch (length % 4) {
25      case 3: output[offset + i + 2] = source[i + 2] ^ mask[2];
26      case 2: output[offset + i + 1] = source[i + 1] ^ mask[1];
27      case 1: output[offset + i] = source[i] ^ mask[0];
28      case 0:;
29    }
30  },
31  unmask: function(data, mask) {
32    var maskNum = mask.readUInt32LE(0, true);
33    var length = data.length;
34    var i = 0;
35    for (; i < length - 3; i += 4) {
36      var num = maskNum ^ data.readUInt32LE(i, true);
37      if (num < 0) num = 4294967296 + num;
38      data.writeUInt32LE(num, i, true);
39    }
40    switch (length % 4) {
41      case 3: data[i + 2] = data[i + 2] ^ mask[2];
42      case 2: data[i + 1] = data[i + 1] ^ mask[1];
43      case 1: data[i] = data[i] ^ mask[0];
44      case 0:;
45    }
46  }
47}