text: /*!
   * ws: a node.js websocket client
   * Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
   * MIT Licensed
   */
  
  'use strict';
  
  const safeBuffer = require('safe-buffer');
  
  const Buffer = safeBuffer.Buffer;
  
  /**
   * Merges an array of buffers into a new buffer.
   *
   * @param {Buffer[]} list The array of buffers to concat
   * @param {Number} totalLength The total length of buffers in the list
   * @return {Buffer} The resulting buffer
   * @public
   */
  const concat = (list, totalLength) => {
    const target = Buffer.allocUnsafe(totalLength);
    var offset = 0;
  
    for (var i = 0; i < list.length; i++) {
      const buf = list[i];
      target.set(buf, offset);
      offset += buf.length;
    }
  
    return target;
  };
  
  try {
    const bufferUtil = require('bufferutil');
  
    module.exports = Object.assign({ concat }, bufferUtil.BufferUtil || bufferUtil);
  } catch (e) /* istanbul ignore next */ {
    /**
     * Masks a buffer using the given mask.
     *
     * @param {Buffer} source The buffer to mask
     * @param {Buffer} mask The mask to use
     * @param {Buffer} output The buffer where to store the result
     * @param {Number} offset The offset at which to start writing
     * @param {Number} length The number of bytes to mask.
     * @public
     */
    const _mask = (source, mask, output, offset, length) => {
      for (var i = 0; i < length; i++) {
        output[offset + i] = source[i] ^ mask[i & 3];
      }
    };
  
    /**
     * Unmasks a buffer using the given mask.
     *
     * @param {Buffer} buffer The buffer to unmask
     * @param {Buffer} mask The mask to use
     * @public
     */
    const _unmask = (buffer, mask) => {
      // Required until https://github.com/nodejs/node/issues/9006 is resolved.
      const length = buffer.length;
      for (var i = 0; i < length; i++) {
        buffer[i] ^= mask[i & 3];
      }
    };
  
  
    try {
      const bufferUtil = require('bufferutil');
      const bu = bufferUtil.BufferUtil || bufferUtil;
  
      module.exports = {
        concat,
        mask(source, mask, output, offset, length) {
          if (length < 48) _mask(source, mask, output, offset, length);
          else bu.mask(source, mask, output, offset, length);
        },
        unmask(buffer, mask) {
          if (buffer.length < 32) _unmask(buffer, mask);
          else bu.unmask(buffer, mask);
        }
      };
    } catch (e) /* istanbul ignore next */ {
      module.exports = {
        concat,
        mask: _mask,
        unmask: _unmask
      };
    }
  }
  