text: 'use strict';
  
  function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
  
  var Buffer = require('safe-buffer').Buffer;
  var util = require('util');
  
  function copyBuffer(src, target, offset) {
    src.copy(target, offset);
  }
  
  module.exports = function () {
    function BufferList() {
      _classCallCheck(this, BufferList);
  
      this.head = null;
      this.tail = null;
      this.length = 0;
    }
  
    BufferList.prototype.push = function push(v) {
      var entry = { data: v, next: null };
      if (this.length > 0) this.tail.next = entry;else this.head = entry;
      this.tail = entry;
      ++this.length;
    };
  
    BufferList.prototype.unshift = function unshift(v) {
      var entry = { data: v, next: this.head };
      if (this.length === 0) this.tail = entry;
      this.head = entry;
      ++this.length;
    };
  
    BufferList.prototype.shift = function shift() {
      if (this.length === 0) return;
      var ret = this.head.data;
      if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
      --this.length;
      return ret;
    };
  
    BufferList.prototype.clear = function clear() {
      this.head = this.tail = null;
      this.length = 0;
    };
  
    BufferList.prototype.join = function join(s) {
      if (this.length === 0) return '';
      var p = this.head;
      var ret = '' + p.data;
      while (p = p.next) {
        ret += s + p.data;
      }return ret;
    };
  
    BufferList.prototype.concat = function concat(n) {
      if (this.length === 0) return Buffer.alloc(0);
      if (this.length === 1) return this.head.data;
      var ret = Buffer.allocUnsafe(n >>> 0);
      var p = this.head;
      var i = 0;
      while (p) {
        copyBuffer(p.data, ret, i);
        i += p.data.length;
        p = p.next;
      }
      return ret;
    };
  
    return BufferList;
  }();
  
  if (util && util.inspect && util.inspect.custom) {
    module.exports.prototype[util.inspect.custom] = function () {
      var obj = util.inspect({ length: this.length });
      return this.constructor.name + ' ' + obj;
    };
  }