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/*!
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 * Copied from:
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 * ws: a node.js websocket client
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 * Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
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 * MIT Licensed
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 */
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/* jshint -W086 */
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module.exports.BufferUtil = {
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  merge: function(mergedBuffer, buffers) {
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    var offset = 0;
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    for (var i = 0, l = buffers.length; i < l; ++i) {
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      var buf = buffers[i];
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      buf.copy(mergedBuffer, offset);
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      offset += buf.length;
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    }
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  },
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  mask: function(source, mask, output, offset, length) {
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    var maskNum = mask.readUInt32LE(0, true);
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    var i = 0;
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    for (; i < length - 3; i += 4) {
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      var num = maskNum ^ source.readUInt32LE(i, true);
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      if (num < 0) { num = 4294967296 + num; }
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      output.writeUInt32LE(num, offset + i, true);
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    }
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    switch (length % 4) {
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      case 3: output[offset + i + 2] = source[i + 2] ^ mask[2];
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      case 2: output[offset + i + 1] = source[i + 1] ^ mask[1];
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      case 1: output[offset + i] = source[i] ^ mask[0];
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      case 0:
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    }
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  },
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  unmask: function(data, mask) {
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    var maskNum = mask.readUInt32LE(0, true);
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    var length = data.length;
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    var i = 0;
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    for (; i < length - 3; i += 4) {
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      var num = maskNum ^ data.readUInt32LE(i, true);
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      if (num < 0) { num = 4294967296 + num; }
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      data.writeUInt32LE(num, i, true);
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    }
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    switch (length % 4) {
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      case 3: data[i + 2] = data[i + 2] ^ mask[2];
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      case 2: data[i + 1] = data[i + 1] ^ mask[1];
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      case 1: data[i] = data[i] ^ mask[0];
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      case 0:
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    }
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  }
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};
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/* jshint +W086 */