socket.io-stream/socket.io-stream.js

stream for socket.io

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.ss = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){

module.exports = require('./lib');


},{"./lib":3}],2:[function(require,module,exports){
(function (Buffer){
var util = require('util');
var Readable = require('stream').Readable;
var bind = require('component-bind');


module.exports = BlobReadStream;

util.inherits(BlobReadStream, Readable);

/**
 * Readable stream for Blob and File on browser.
 *
 * @param {Object} options
 * @api private
 */
function BlobReadStream(blob, options) {
  if (!(this instanceof BlobReadStream)) {
    return new BlobReadStream(blob, options);
  }

  Readable.call(this, options);

  options = options || {};
  this.blob = blob;
  this.slice = blob.slice || blob.webkitSlice || blob.mozSlice;
  this.start = 0;
  this.sync = options.synchronous || false;

  var fileReader;

  if (options.synchronous) {
    fileReader = this.fileReader = new FileReaderSync();
  } else {
    fileReader = this.fileReader = new FileReader();
  }

  fileReader.onload = bind(this, '_onload');
  fileReader.onerror = bind(this, '_onerror');
}

BlobReadStream.prototype._read = function(size) {
  var start = this.start;
  var end = this.start = this.start + size;
  var chunk = this.slice.call(this.blob, start, end);

  if (chunk.size) {
    if (this.sync) {
      var bufferChunk = new Buffer(new Uint8Array(this.fileReader.readAsArrayBuffer(chunk)));
      this.push(bufferChunk);
    } else {
      this.fileReader.readAsArrayBuffer(chunk);
    }
  } else {
    this.push(null);
  }
}

BlobReadStream.prototype._onload = function(e) {
  var chunk = new Buffer(new Uint8Array(e.target.result));
  this.push(chunk);
};

BlobReadStream.prototype._onerror = function(e) {
  var err = e.target.error;
  this.emit('error', err);
};


}).call(this,require("buffer").Buffer)
},{"buffer":11,"component-bind":12,"stream":35,"util":40}],3:[function(require,module,exports){
(function (Buffer){
var Socket = require('./socket');
var IOStream = require('./iostream');
var BlobReadStream = require('./blob-read-stream');


exports = module.exports = lookup;

/**
 * Expose Node Buffer for browser.
 *
 * @api public
 */
exports.Buffer = Buffer;

/**
 * Expose Socket constructor.
 *
 * @api public
 */
exports.Socket = Socket;

/**
 * Expose IOStream constructor.
 *
 * @api public
 */
exports.IOStream = IOStream;

/**
 * Forces base 64 encoding when emitting. Must be set to true for Socket.IO v0.9 or lower.
 *
 * @api public
 */
exports.forceBase64 = false;

/**
 * Look up an existing Socket.
 *
 * @param {socket.io#Socket} socket.io
 * @param {Object} options
 * @return {Socket} Socket instance
 * @api public
 */
function lookup(sio, options) {
  options = options || {};
  if (null == options.forceBase64) {
    options.forceBase64 = exports.forceBase64;
  }

  if (!sio._streamSocket) {
    sio._streamSocket = new Socket(sio, options);
  }
  return sio._streamSocket;
}

/**
 * Creates a new duplex stream.
 *
 * @param {Object} options
 * @return {IOStream} duplex stream
 * @api public
 */
exports.createStream = function(options) {
  return new IOStream(options);
};

/**
 * Creates a new readable stream for Blob/File on browser.
 *
 * @param {Blob} blob
 * @param {Object} options
 * @return {BlobReadStream} stream
 * @api public
 */
exports.createBlobReadStream = function(blob, options) {
  return new BlobReadStream(blob, options);
};

}).call(this,require("buffer").Buffer)
},{"./blob-read-stream":2,"./iostream":4,"./socket":6,"buffer":11}],4:[function(require,module,exports){
var util = require('util');
var Duplex = require('stream').Duplex;
var bind = require('component-bind');
var uuid = require('./uuid');
var debug = require('debug')('socket.io-stream:iostream');


module.exports = IOStream;

util.inherits(IOStream, Duplex);

/**
 * Duplex
 *
 * @param {Object} options
 * @api private
 */
function IOStream(options) {
  if (!(this instanceof IOStream)) {
    return new IOStream(options);
  }

  IOStream.super_.call(this, options);

  this.options = options;
  this.id = uuid();
  this.socket = null;

  // Buffers
  this.pushBuffer = [];
  this.writeBuffer = [];

  // Op states
  this._readable = false;
  this._writable = false;
  this.destroyed = false;

  // default to *not* allowing half open sockets
  this.allowHalfOpen = options && options.allowHalfOpen || false;

  this.on('finish', this._onfinish);
  this.on('end', this._onend);
  this.on('error', this._onerror);
}

/**
 * Ensures that no more I/O activity happens on this stream.
 * Not necessary in the usual case.
 *
 * @api public
 */
IOStream.prototype.destroy = function() {
  debug('destroy');

  if (this.destroyed) {
    debug('already destroyed');
    return;
  }

  this.readable = this.writable = false;

  if (this.socket) {
    debug('clean up');
    this.socket.cleanup(this.id);
    this.socket = null;
  }

  this.destroyed = true;
};

/**
 * Local read
 *
 * @api private
 */
IOStream.prototype._read = function(size) {
  var push;

  // We can not read from the socket if it's destroyed obviously ...
  if (this.destroyed) return;

  if (this.pushBuffer.length) {
    // flush buffer and end if it exists.
    while (push = this.pushBuffer.shift()) {
      if (!push()) break;
    }
    return;
  }

  this._readable = true;

  // Go get data from remote stream
  // Calls
  // ._onread remotely
  // then
  // ._onwrite locally
  this.socket._read(this.id, size);
};


/**
 * Read from remote stream
 *
 * @api private
 */
IOStream.prototype._onread = function(size) {
  var write = this.writeBuffer.shift();
  if (write) return write();

  this._writable = true;
};

/**
 * Write local data to remote stream
 * Calls
 * remtote ._onwrite
 *
 * @api private
 */
IOStream.prototype._write = function(chunk, encoding, callback) {
  var self = this;

  function write() {
    // We can not write to the socket if it's destroyed obviously ...
    if (self.destroyed) return;

    self._writable = false;
    self.socket._write(self.id, chunk, encoding, callback);
  }

  if (this._writable) {
    write();
  } else {
    this.writeBuffer.push(write);
  }
};

/**
 * Write the data fetched remotely
 * so that we can now read locally
 *
 * @api private
 */
IOStream.prototype._onwrite = function(chunk, encoding, callback) {
  var self = this;

  function push() {
    self._readable = false;
    var ret = self.push(chunk || '', encoding);
    callback();
    return ret;
  }

  if (this._readable) {
    push();
  } else {
    this.pushBuffer.push(push);
  }
};

/**
 * When ending send 'end' event to remote stream
 *
 * @api private
 */
IOStream.prototype._end = function() {
  if (this.pushBuffer.length) {
    // end after flushing buffer.
    this.pushBuffer.push(bind(this, '_done'));
  } else {
    this._done();
  }
};

/**
 * Remote stream just ended
 *
 * @api private
 */
IOStream.prototype._done = function() {
  this._readable = false;

  // signal the end of the data.
  return this.push(null);
};

/**
 * the user has called .end(), and all the bytes have been
 * sent out to the other side.
 * If allowHalfOpen is false, or if the readable side has
 * ended already, then destroy.
 * If allowHalfOpen is true, then we need to set writable false,
 * so that only the writable side will be cleaned up.
 *
 * @api private
 */
IOStream.prototype._onfinish = function() {
  debug('_onfinish');
  // Local socket just finished
  // send 'end' event to remote
  if (this.socket) {
    this.socket._end(this.id);
  }

  this.writable = false;
  this._writableState.ended = true;

  if (!this.readable || this._readableState.ended) {
    debug('_onfinish: ended, destroy %s', this._readableState);
    return this.destroy();
  }

  debug('_onfinish: not ended');

  if (!this.allowHalfOpen) {
    this.push(null);

    // just in case we're waiting for an EOF.
    if (this.readable && !this._readableState.endEmitted) {
      this.read(0);
    }
  }
};

/**
 * the EOF has been received, and no more bytes are coming.
 * if the writable side has ended already, then clean everything
 * up.
 *
 * @api private
 */
IOStream.prototype._onend = function() {
  debug('_onend');
  this.readable = false;
  this._readableState.ended = true;

  if (!this.writable || this._writableState.finished) {
    debug('_onend: %s', this._writableState);
    return this.destroy();
  }

  debug('_onend: not finished');

  if (!this.allowHalfOpen) {
    this.end();
  }
};

/**
 * When error in local stream
 * notyify remote
 * if err.remote = true
 * then error happened on remote stream
 *
 * @api private
 */
IOStream.prototype._onerror = function(err) {
  // check if the error came from remote stream.
  if (!err.remote && this.socket) {
    // notify the error to the corresponding remote stream.
    this.socket._error(this.id, err);
  }

  this.destroy();
};

},{"./uuid":7,"component-bind":12,"debug":14,"stream":35,"util":40}],5:[function(require,module,exports){
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var IOStream = require('./iostream');
var slice = Array.prototype.slice;

exports.Encoder = Encoder;
exports.Decoder = Decoder;

util.inherits(Encoder, EventEmitter);

function Encoder() {
  EventEmitter.call(this);
}

/**
 * Encode streams to placeholder objects.
 *
 * @api public
 */
Encoder.prototype.encode = function(v) {
  if (v instanceof IOStream) {
    return this.encodeStream(v);
  } else if (util.isArray(v)) {
    return this.encodeArray(v);
  } else if (v && 'object' == typeof v) {
    return this.encodeObject(v);
  }
  return v;
}

Encoder.prototype.encodeStream = function(stream) {
  this.emit('stream', stream);

  // represent a stream in an object.
  var v = { $stream: stream.id };
  if (stream.options) {
    v.options = stream.options;
  }
  return v;
}

Encoder.prototype.encodeArray = function(arr) {
  var v = [];
  for (var i = 0, len = arr.length; i < len; i++) {
    v.push(this.encode(arr[i]));
  }
  return v;
}

Encoder.prototype.encodeObject = function(obj) {
  var v = {};
  for (var k in obj) {
    if (obj.hasOwnProperty(k)) {
      v[k] = this.encode(obj[k]);
    }
  }
  return v;
}

util.inherits(Decoder, EventEmitter);

function Decoder() {
  EventEmitter.call(this);
}

/**
 * Decode placeholder objects to streams.
 *
 * @api public
 */
Decoder.prototype.decode = function(v) {
  if (v && v.$stream) {
    return this.decodeStream(v);
  } else if (util.isArray(v)) {
    return this.decodeArray(v);
  } else if (v && 'object' == typeof v) {
    return this.decodeObject(v);
  }
  return v;
}

Decoder.prototype.decodeStream = function(obj) {
  var stream = new IOStream(obj.options);
  stream.id = obj.$stream;
  this.emit('stream', stream);
  return stream;
}

Decoder.prototype.decodeArray = function(arr) {
  var v = [];
  for (var i = 0, len = arr.length; i < len; i++) {
    v.push(this.decode(arr[i]));
  }
  return v;
}

Decoder.prototype.decodeObject = function(obj) {
  var v = {};
  for (var k in obj) {
    if (obj.hasOwnProperty(k)) {
      v[k] = this.decode(obj[k]);
    }
  }
  return v;
}

},{"./iostream":4,"events":16,"util":40}],6:[function(require,module,exports){
(function (global,Buffer){
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var bind = require('component-bind');
var IOStream = require('./iostream');
var parser = require('./parser');
var debug = require('debug')('socket.io-stream:socket');
var emit = EventEmitter.prototype.emit;
var on = EventEmitter.prototype.on;
var slice = Array.prototype.slice;


exports = module.exports = Socket;

/**
 * Base event name for messaging.
 *
 * @api public
 */
exports.event = '$stream';

exports.events = [
  'error',
  'newListener',
  'removeListener'
];

util.inherits(Socket, EventEmitter);

/**
 * Bidirectional stream socket which wraps Socket.IO.
 *
 * @param {socket.io#Socket} socket.io
 * @api public
 */
function Socket(sio, options) {
  if (!(this instanceof Socket)) {
    return new Socket(sio, options);
  }

  EventEmitter.call(this);

  options = options || {};

  this.sio = sio;
  this.forceBase64 = !!options.forceBase64;
  this.streams = {};
  this.encoder = new parser.Encoder();
  this.decoder = new parser.Decoder();

  var eventName = exports.event;
  sio.on(eventName, bind(this, emit));
  sio.on(eventName + '-read', bind(this, '_onread'));
  sio.on(eventName + '-write', bind(this, '_onwrite'));
  sio.on(eventName + '-end', bind(this, '_onend'));
  sio.on(eventName + '-error', bind(this, '_onerror'));
  sio.on('error', bind(this, emit, 'error'));
  sio.on('disconnect', bind(this, '_ondisconnect'));

  this.encoder.on('stream', bind(this, '_onencode'));
  this.decoder.on('stream', bind(this, '_ondecode'));
}

/**
 * Original emit function.
 *
 * @api private
 */
Socket.prototype.$emit = emit;

/**
 * Emits streams to this corresponding server/client.
 *
 * @return {Socket} self
 * @api public
 */
Socket.prototype.emit = function(type) {
  if (~exports.events.indexOf(type)) {
    return emit.apply(this, arguments);
  }
  this._stream.apply(this, arguments);
  return this;
};

Socket.prototype.on = function(type, listener) {
  if (~exports.events.indexOf(type)) {
    return on.apply(this, arguments);
  }

  this._onstream(type, listener);
  return this;
};

/**
 * Sends a new stream request.
 *
 * @param {String} event type
 * @api private
 */
Socket.prototype._stream = function(type) {
  debug('sending new streams');

  var self = this;
  var args = slice.call(arguments, 1);
  var ack = args[args.length - 1];
  if ('function' == typeof ack) {
    args[args.length - 1] = function() {
      var args = slice.call(arguments);
      args = self.decoder.decode(args);
      ack.apply(this, args);
    };
  }

  args = this.encoder.encode(args);
  var sio = this.sio;
  sio.emit.apply(sio, [exports.event, type].concat(args));
};

/**
 * Notifies the read event.
 *
 * @api private
 */
Socket.prototype._read = function(id, size) {
  this.sio.emit(exports.event + '-read', id, size);
};

/**
 * Requests to write a chunk.
 *
 * @api private
 */
Socket.prototype._write = function(id, chunk, encoding, callback) {
  if (Buffer.isBuffer(chunk)) {
    if (this.forceBase64) {
      encoding = 'base64';
      chunk = chunk.toString(encoding);
    } else if (!global.Buffer) {
      // socket.io can't handle Buffer when using browserify.
      if (chunk.toArrayBuffer) {
        chunk = chunk.toArrayBuffer();
      } else {
        chunk = chunk.buffer;
      }
    }
  }
  this.sio.emit(exports.event + '-write', id, chunk, encoding, callback);
};

Socket.prototype._end = function(id) {
  this.sio.emit(exports.event + '-end', id);
};

Socket.prototype._error = function(id, err) {
  this.sio.emit(exports.event + '-error', id, err.message || err);
};

/**
 * Handles a new stream request.
 *
 * @param {String} event type
 * @param {Function} listener
 *
 * @api private
 */
Socket.prototype._onstream = function(type, listener) {
  if ('function' != typeof listener) {
    throw TypeError('listener must be a function');
  }

  function onstream() {
    debug('new streams');
    var self = this;
    var args = slice.call(arguments);
    var ack = args[args.length - 1];
    if ('function' == typeof ack) {
      args[args.length - 1] = function() {
        var args = slice.call(arguments);
        args = self.encoder.encode(args);
        ack.apply(this, args);
      };
    }

    args = this.decoder.decode(args);
    listener.apply(this, args);
  }

  // for removeListener
  onstream.listener = listener;

  on.call(this, type, onstream);
};

Socket.prototype._onread = function(id, size) {
  debug('read: "%s"', id);

  var stream = this.streams[id];
  if (stream) {
    stream._onread(size);
  } else {
    debug('ignore invalid stream id');
  }
};

Socket.prototype._onwrite = function(id, chunk, encoding, callback) {
  debug('write: "%s"', id);

  var stream = this.streams[id];
  if (!stream) {
    callback('invalid stream id: ' + id);
    return;
  }

  if (global.ArrayBuffer && chunk instanceof ArrayBuffer) {
    // make sure that chunk is a buffer for stream
    chunk = new Buffer(new Uint8Array(chunk));
  }
  stream._onwrite(chunk, encoding, callback);
};

Socket.prototype._onend = function(id) {
  debug('end: "%s"', id);

  var stream = this.streams[id];
  if (!stream) {
    debug('ignore non-existent stream id: "%s"', id);
    return;
  }

  stream._end();
};

Socket.prototype._onerror = function(id, message) {
  debug('error: "%s", "%s"', id, message);

  var stream = this.streams[id];
  if (!stream) {
    debug('invalid stream id: "%s"', id);
    return;
  }

  var err = new Error(message);
  err.remote = true;
  stream.emit('error', err);
};

Socket.prototype._ondisconnect = function() {
  var stream;
  for (var id in this.streams) {
    stream = this.streams[id];
    stream.destroy();

    // Close streams when the underlaying
    // socket.io connection is closed (regardless why)
    stream.emit('close');
    stream.emit('error', new Error('Connection aborted'));
  }
};

Socket.prototype._onencode = function(stream) {
  if (stream.socket || stream.destroyed) {
    throw new Error('stream has already been sent.');
  }

  var id = stream.id;
  if (this.streams[id]) {
    throw new Error('Encoded stream already exists: ' + id);
  }

  this.streams[id] = stream;
  stream.socket = this;
};

Socket.prototype._ondecode = function(stream) {
  var id = stream.id;
  if (this.streams[id]) {
    this._error(id, new Error('Decoded stream already exists: ' + id));
    return;
  }

  this.streams[id] = stream;
  stream.socket = this;
};

Socket.prototype.cleanup = function(id) {
  delete this.streams[id];
};


}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {},require("buffer").Buffer)
},{"./iostream":4,"./parser":5,"buffer":11,"component-bind":12,"debug":14,"events":16,"util":40}],7:[function(require,module,exports){
// UUID function from https://gist.github.com/jed/982883
// More lightweight than node-uuid
function b(
  a                  // placeholder
){
  return a           // if the placeholder was passed, return
    ? (              // a random number from 0 to 15
      a ^            // unless b is 8,
      Math.random()  // in which case
      * 16           // a random number from
      >> a/4         // 8 to 11
      ).toString(16) // in hexadecimal
    : (              // or otherwise a concatenated string:
      [1e7] +        // 10000000 +
      -1e3 +         // -1000 +
      -4e3 +         // -4000 +
      -8e3 +         // -80000000 +
      -1e11          // -100000000000,
      ).replace(     // replacing
        /[018]/g,    // zeroes, ones, and eights with
        b            // random hex digits
      )
}

module.exports = b;

},{}],8:[function(require,module,exports){
'use strict'

exports.byteLength = byteLength
exports.toByteArray = toByteArray
exports.fromByteArray = fromByteArray

var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array

var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var i = 0, len = code.length; i < len; ++i) {
  lookup[i] = code[i]
  revLookup[code.charCodeAt(i)] = i
}

revLookup['-'.charCodeAt(0)] = 62
revLookup['_'.charCodeAt(0)] = 63

function placeHoldersCount (b64) {
  var len = b64.length
  if (len % 4 > 0) {
    throw new Error('Invalid string. Length must be a multiple of 4')
  }

  // the number of equal signs (place holders)
  // if there are two placeholders, than the two characters before it
  // represent one byte
  // if there is only one, then the three characters before it represent 2 bytes
  // this is just a cheap hack to not do indexOf twice
  return b64[len - 2] === '=' ? 2 : b64[len - 1] === '=' ? 1 : 0
}

function byteLength (b64) {
  // base64 is 4/3 + up to two characters of the original data
  return b64.length * 3 / 4 - placeHoldersCount(b64)
}

function toByteArray (b64) {
  var i, j, l, tmp, placeHolders, arr
  var len = b64.length
  placeHolders = placeHoldersCount(b64)

  arr = new Arr(len * 3 / 4 - placeHolders)

  // if there are placeholders, only get up to the last complete 4 chars
  l = placeHolders > 0 ? len - 4 : len

  var L = 0

  for (i = 0, j = 0; i < l; i += 4, j += 3) {
    tmp = (revLookup[b64.charCodeAt(i)] << 18) | (revLookup[b64.charCodeAt(i + 1)] << 12) | (revLookup[b64.charCodeAt(i + 2)] << 6) | revLookup[b64.charCodeAt(i + 3)]
    arr[L++] = (tmp >> 16) & 0xFF
    arr[L++] = (tmp >> 8) & 0xFF
    arr[L++] = tmp & 0xFF
  }

  if (placeHolders === 2) {
    tmp = (revLookup[b64.charCodeAt(i)] << 2) | (revLookup[b64.charCodeAt(i + 1)] >> 4)
    arr[L++] = tmp & 0xFF
  } else if (placeHolders === 1) {
    tmp = (revLookup[b64.charCodeAt(i)] << 10) | (revLookup[b64.charCodeAt(i + 1)] << 4) | (revLookup[b64.charCodeAt(i + 2)] >> 2)
    arr[L++] = (tmp >> 8) & 0xFF
    arr[L++] = tmp & 0xFF
  }

  return arr
}

function tripletToBase64 (num) {
  return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F]
}

function encodeChunk (uint8, start, end) {
  var tmp
  var output = []
  for (var i = start; i < end; i += 3) {
    tmp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2])
    output.push(tripletToBase64(tmp))
  }
  return output.join('')
}

function fromByteArray (uint8) {
  var tmp
  var len = uint8.length
  var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
  var output = ''
  var parts = []
  var maxChunkLength = 16383 // must be multiple of 3

  // go through the array every three bytes, we'll deal with trailing stuff later
  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
    parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)))
  }

  // pad the end with zeros, but make sure to not forget the extra bytes
  if (extraBytes === 1) {
    tmp = uint8[len - 1]
    output += lookup[tmp >> 2]
    output += lookup[(tmp << 4) & 0x3F]
    output += '=='
  } else if (extraBytes === 2) {
    tmp = (uint8[len - 2] << 8) + (uint8[len - 1])
    output += lookup[tmp >> 10]
    output += lookup[(tmp >> 4) & 0x3F]
    output += lookup[(tmp << 2) & 0x3F]
    output += '='
  }

  parts.push(output)

  return parts.join('')
}

},{}],9:[function(require,module,exports){

},{}],10:[function(require,module,exports){
(function (global){
'use strict';

var buffer = require('buffer');
var Buffer = buffer.Buffer;
var SlowBuffer = buffer.SlowBuffer;
var MAX_LEN = buffer.kMaxLength || 2147483647;
exports.alloc = function alloc(size, fill, encoding) {
  if (typeof Buffer.alloc === 'function') {
    return Buffer.alloc(size, fill, encoding);
  }
  if (typeof encoding === 'number') {
    throw new TypeError('encoding must not be number');
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size > MAX_LEN) {
    throw new RangeError('size is too large');
  }
  var enc = encoding;
  var _fill = fill;
  if (_fill === undefined) {
    enc = undefined;
    _fill = 0;
  }
  var buf = new Buffer(size);
  if (typeof _fill === 'string') {
    var fillBuf = new Buffer(_fill, enc);
    var flen = fillBuf.length;
    var i = -1;
    while (++i < size) {
      buf[i] = fillBuf[i % flen];
    }
  } else {
    buf.fill(_fill);
  }
  return buf;
}
exports.allocUnsafe = function allocUnsafe(size) {
  if (typeof Buffer.allocUnsafe === 'function') {
    return Buffer.allocUnsafe(size);
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size > MAX_LEN) {
    throw new RangeError('size is too large');
  }
  return new Buffer(size);
}
exports.from = function from(value, encodingOrOffset, length) {
  if (typeof Buffer.from === 'function' && (!global.Uint8Array || Uint8Array.from !== Buffer.from)) {
    return Buffer.from(value, encodingOrOffset, length);
  }
  if (typeof value === 'number') {
    throw new TypeError('"value" argument must not be a number');
  }
  if (typeof value === 'string') {
    return new Buffer(value, encodingOrOffset);
  }
  if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
    var offset = encodingOrOffset;
    if (arguments.length === 1) {
      return new Buffer(value);
    }
    if (typeof offset === 'undefined') {
      offset = 0;
    }
    var len = length;
    if (typeof len === 'undefined') {
      len = value.byteLength - offset;
    }
    if (offset >= value.byteLength) {
      throw new RangeError('\'offset\' is out of bounds');
    }
    if (len > value.byteLength - offset) {
      throw new RangeError('\'length\' is out of bounds');
    }
    return new Buffer(value.slice(offset, offset + len));
  }
  if (Buffer.isBuffer(value)) {
    var out = new Buffer(value.length);
    value.copy(out, 0, 0, value.length);
    return out;
  }
  if (value) {
    if (Array.isArray(value) || (typeof ArrayBuffer !== 'undefined' && value.buffer instanceof ArrayBuffer) || 'length' in value) {
      return new Buffer(value);
    }
    if (value.type === 'Buffer' && Array.isArray(value.data)) {
      return new Buffer(value.data);
    }
  }

  throw new TypeError('First argument must be a string, Buffer, ' + 'ArrayBuffer, Array, or array-like object.');
}
exports.allocUnsafeSlow = function allocUnsafeSlow(size) {
  if (typeof Buffer.allocUnsafeSlow === 'function') {
    return Buffer.allocUnsafeSlow(size);
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size >= MAX_LEN) {
    throw new RangeError('size is too large');
  }
  return new SlowBuffer(size);
}

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"buffer":11}],11:[function(require,module,exports){
(function (global){
/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
 * @license  MIT
 */
/* eslint-disable no-proto */

'use strict'

var base64 = require('base64-js')
var ieee754 = require('ieee754')
var isArray = require('isarray')

exports.Buffer = Buffer
exports.SlowBuffer = SlowBuffer
exports.INSPECT_MAX_BYTES = 50

/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Use Object implementation (most compatible, even IE6)
 *
 * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
 * Opera 11.6+, iOS 4.2+.
 *
 * Due to various browser bugs, sometimes the Object implementation will be used even
 * when the browser supports typed arrays.
 *
 * Note:
 *
 *   - Firefox 4-29 lacks support for adding new properties to `Uint8Array` instances,
 *     See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
 *
 *   - Chrome 9-10 is missing the `TypedArray.prototype.subarray` function.
 *
 *   - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
 *     incorrect length in some situations.

 * We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they
 * get the Object implementation, which is slower but behaves correctly.
 */
Buffer.TYPED_ARRAY_SUPPORT = global.TYPED_ARRAY_SUPPORT !== undefined
  ? global.TYPED_ARRAY_SUPPORT
  : typedArraySupport()

/*
 * Export kMaxLength after typed array support is determined.
 */
exports.kMaxLength = kMaxLength()

function typedArraySupport () {
  try {
    var arr = new Uint8Array(1)
    arr.__proto__ = {__proto__: Uint8Array.prototype, foo: function () { return 42 }}
    return arr.foo() === 42 && // typed array instances can be augmented
        typeof arr.subarray === 'function' && // chrome 9-10 lack `subarray`
        arr.subarray(1, 1).byteLength === 0 // ie10 has broken `subarray`
  } catch (e) {
    return false
  }
}

function kMaxLength () {
  return Buffer.TYPED_ARRAY_SUPPORT
    ? 0x7fffffff
    : 0x3fffffff
}

function createBuffer (that, length) {
  if (kMaxLength() < length) {
    throw new RangeError('Invalid typed array length')
  }
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = new Uint8Array(length)
    that.__proto__ = Buffer.prototype
  } else {
    // Fallback: Return an object instance of the Buffer class
    if (that === null) {
      that = new Buffer(length)
    }
    that.length = length
  }

  return that
}

/**
 * The Buffer constructor returns instances of `Uint8Array` that have their
 * prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
 * `Uint8Array`, so the returned instances will have all the node `Buffer` methods
 * and the `Uint8Array` methods. Square bracket notation works as expected -- it
 * returns a single octet.
 *
 * The `Uint8Array` prototype remains unmodified.
 */

function Buffer (arg, encodingOrOffset, length) {
  if (!Buffer.TYPED_ARRAY_SUPPORT && !(this instanceof Buffer)) {
    return new Buffer(arg, encodingOrOffset, length)
  }

  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new Error(
        'If encoding is specified then the first argument must be a string'
      )
    }
    return allocUnsafe(this, arg)
  }
  return from(this, arg, encodingOrOffset, length)
}

Buffer.poolSize = 8192 // not used by this implementation

// TODO: Legacy, not needed anymore. Remove in next major version.
Buffer._augment = function (arr) {
  arr.__proto__ = Buffer.prototype
  return arr
}

function from (that, value, encodingOrOffset, length) {
  if (typeof value === 'number') {
    throw new TypeError('"value" argument must not be a number')
  }

  if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
    return fromArrayBuffer(that, value, encodingOrOffset, length)
  }

  if (typeof value === 'string') {
    return fromString(that, value, encodingOrOffset)
  }

  return fromObject(that, value)
}

/**
 * Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
 * if value is a number.
 * Buffer.from(str[, encoding])
 * Buffer.from(array)
 * Buffer.from(buffer)
 * Buffer.from(arrayBuffer[, byteOffset[, length]])
 **/
Buffer.from = function (value, encodingOrOffset, length) {
  return from(null, value, encodingOrOffset, length)
}

if (Buffer.TYPED_ARRAY_SUPPORT) {
  Buffer.prototype.__proto__ = Uint8Array.prototype
  Buffer.__proto__ = Uint8Array
  if (typeof Symbol !== 'undefined' && Symbol.species &&
      Buffer[Symbol.species] === Buffer) {
    // Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
    Object.defineProperty(Buffer, Symbol.species, {
      value: null,
      configurable: true
    })
  }
}

function assertSize (size) {
  if (typeof size !== 'number') {
    throw new TypeError('"size" argument must be a number')
  } else if (size < 0) {
    throw new RangeError('"size" argument must not be negative')
  }
}

function alloc (that, size, fill, encoding) {
  assertSize(size)
  if (size <= 0) {
    return createBuffer(that, size)
  }
  if (fill !== undefined) {
    // Only pay attention to encoding if it's a string. This
    // prevents accidentally sending in a number that would
    // be interpretted as a start offset.
    return typeof encoding === 'string'
      ? createBuffer(that, size).fill(fill, encoding)
      : createBuffer(that, size).fill(fill)
  }
  return createBuffer(that, size)
}

/**
 * Creates a new filled Buffer instance.
 * alloc(size[, fill[, encoding]])
 **/
Buffer.alloc = function (size, fill, encoding) {
  return alloc(null, size, fill, encoding)
}

function allocUnsafe (that, size) {
  assertSize(size)
  that = createBuffer(that, size < 0 ? 0 : checked(size) | 0)
  if (!Buffer.TYPED_ARRAY_SUPPORT) {
    for (var i = 0; i < size; ++i) {
      that[i] = 0
    }
  }
  return that
}

/**
 * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
 * */
Buffer.allocUnsafe = function (size) {
  return allocUnsafe(null, size)
}
/**
 * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
 */
Buffer.allocUnsafeSlow = function (size) {
  return allocUnsafe(null, size)
}

function fromString (that, string, encoding) {
  if (typeof encoding !== 'string' || encoding === '') {
    encoding = 'utf8'
  }

  if (!Buffer.isEncoding(encoding)) {
    throw new TypeError('"encoding" must be a valid string encoding')
  }

  var length = byteLength(string, encoding) | 0
  that = createBuffer(that, length)

  var actual = that.write(string, encoding)

  if (actual !== length) {
    // Writing a hex string, for example, that contains invalid characters will
    // cause everything after the first invalid character to be ignored. (e.g.
    // 'abxxcd' will be treated as 'ab')
    that = that.slice(0, actual)
  }

  return that
}

function fromArrayLike (that, array) {
  var length = array.length < 0 ? 0 : checked(array.length) | 0
  that = createBuffer(that, length)
  for (var i = 0; i < length; i += 1) {
    that[i] = array[i] & 255
  }
  return that
}

function fromArrayBuffer (that, array, byteOffset, length) {
  array.byteLength // this throws if `array` is not a valid ArrayBuffer

  if (byteOffset < 0 || array.byteLength < byteOffset) {
    throw new RangeError('\'offset\' is out of bounds')
  }

  if (array.byteLength < byteOffset + (length || 0)) {
    throw new RangeError('\'length\' is out of bounds')
  }

  if (byteOffset === undefined && length === undefined) {
    array = new Uint8Array(array)
  } else if (length === undefined) {
    array = new Uint8Array(array, byteOffset)
  } else {
    array = new Uint8Array(array, byteOffset, length)
  }

  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = array
    that.__proto__ = Buffer.prototype
  } else {
    // Fallback: Return an object instance of the Buffer class
    that = fromArrayLike(that, array)
  }
  return that
}

function fromObject (that, obj) {
  if (Buffer.isBuffer(obj)) {
    var len = checked(obj.length) | 0
    that = createBuffer(that, len)

    if (that.length === 0) {
      return that
    }

    obj.copy(that, 0, 0, len)
    return that
  }

  if (obj) {
    if ((typeof ArrayBuffer !== 'undefined' &&
        obj.buffer instanceof ArrayBuffer) || 'length' in obj) {
      if (typeof obj.length !== 'number' || isnan(obj.length)) {
        return createBuffer(that, 0)
      }
      return fromArrayLike(that, obj)
    }

    if (obj.type === 'Buffer' && isArray(obj.data)) {
      return fromArrayLike(that, obj.data)
    }
  }

  throw new TypeError('First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.')
}

function checked (length) {
  // Note: cannot use `length < kMaxLength()` here because that fails when
  // length is NaN (which is otherwise coerced to zero.)
  if (length >= kMaxLength()) {
    throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
                         'size: 0x' + kMaxLength().toString(16) + ' bytes')
  }
  return length | 0
}

function SlowBuffer (length) {
  if (+length != length) { // eslint-disable-line eqeqeq
    length = 0
  }
  return Buffer.alloc(+length)
}

Buffer.isBuffer = function isBuffer (b) {
  return !!(b != null && b._isBuffer)
}

Buffer.compare = function compare (a, b) {
  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
    throw new TypeError('Arguments must be Buffers')
  }

  if (a === b) return 0

  var x = a.length
  var y = b.length

  for (var i = 0, len = Math.min(x, y); i < len; ++i) {
    if (a[i] !== b[i]) {
      x = a[i]
      y = b[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

Buffer.isEncoding = function isEncoding (encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'latin1':
    case 'binary':
    case 'base64':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true
    default:
      return false
  }
}

Buffer.concat = function concat (list, length) {
  if (!isArray(list)) {
    throw new TypeError('"list" argument must be an Array of Buffers')
  }

  if (list.length === 0) {
    return Buffer.alloc(0)
  }

  var i
  if (length === undefined) {
    length = 0
    for (i = 0; i < list.length; ++i) {
      length += list[i].length
    }
  }

  var buffer = Buffer.allocUnsafe(length)
  var pos = 0
  for (i = 0; i < list.length; ++i) {
    var buf = list[i]
    if (!Buffer.isBuffer(buf)) {
      throw new TypeError('"list" argument must be an Array of Buffers')
    }
    buf.copy(buffer, pos)
    pos += buf.length
  }
  return buffer
}

function byteLength (string, encoding) {
  if (Buffer.isBuffer(string)) {
    return string.length
  }
  if (typeof ArrayBuffer !== 'undefined' && typeof ArrayBuffer.isView === 'function' &&
      (ArrayBuffer.isView(string) || string instanceof ArrayBuffer)) {
    return string.byteLength
  }
  if (typeof string !== 'string') {
    string = '' + string
  }

  var len = string.length
  if (len === 0) return 0

  // Use a for loop to avoid recursion
  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'ascii':
      case 'latin1':
      case 'binary':
        return len
      case 'utf8':
      case 'utf-8':
      case undefined:
        return utf8ToBytes(string).length
      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return len * 2
      case 'hex':
        return len >>> 1
      case 'base64':
        return base64ToBytes(string).length
      default:
        if (loweredCase) return utf8ToBytes(string).length // assume utf8
        encoding = ('' + encoding).toLowerCase()
        loweredCase = true
    }
  }
}
Buffer.byteLength = byteLength

function slowToString (encoding, start, end) {
  var loweredCase = false

  // No need to verify that "this.length <= MAX_UINT32" since it's a read-only
  // property of a typed array.

  // This behaves neither like String nor Uint8Array in that we set start/end
  // to their upper/lower bounds if the value passed is out of range.
  // undefined is handled specially as per ECMA-262 6th Edition,
  // Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
  if (start === undefined || start < 0) {
    start = 0
  }
  // Return early if start > this.length. Done here to prevent potential uint32
  // coercion fail below.
  if (start > this.length) {
    return ''
  }

  if (end === undefined || end > this.length) {
    end = this.length
  }

  if (end <= 0) {
    return ''
  }

  // Force coersion to uint32. This will also coerce falsey/NaN values to 0.
  end >>>= 0
  start >>>= 0

  if (end <= start) {
    return ''
  }

  if (!encoding) encoding = 'utf8'

  while (true) {
    switch (encoding) {
      case 'hex':
        return hexSlice(this, start, end)

      case 'utf8':
      case 'utf-8':
        return utf8Slice(this, start, end)

      case 'ascii':
        return asciiSlice(this, start, end)

      case 'latin1':
      case 'binary':
        return latin1Slice(this, start, end)

      case 'base64':
        return base64Slice(this, start, end)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return utf16leSlice(this, start, end)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = (encoding + '').toLowerCase()
        loweredCase = true
    }
  }
}

// The property is used by `Buffer.isBuffer` and `is-buffer` (in Safari 5-7) to detect
// Buffer instances.
Buffer.prototype._isBuffer = true

function swap (b, n, m) {
  var i = b[n]
  b[n] = b[m]
  b[m] = i
}

Buffer.prototype.swap16 = function swap16 () {
  var len = this.length
  if (len % 2 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 16-bits')
  }
  for (var i = 0; i < len; i += 2) {
    swap(this, i, i + 1)
  }
  return this
}

Buffer.prototype.swap32 = function swap32 () {
  var len = this.length
  if (len % 4 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 32-bits')
  }
  for (var i = 0; i < len; i += 4) {
    swap(this, i, i + 3)
    swap(this, i + 1, i + 2)
  }
  return this
}

Buffer.prototype.swap64 = function swap64 () {
  var len = this.length
  if (len % 8 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 64-bits')
  }
  for (var i = 0; i < len; i += 8) {
    swap(this, i, i + 7)
    swap(this, i + 1, i + 6)
    swap(this, i + 2, i + 5)
    swap(this, i + 3, i + 4)
  }
  return this
}

Buffer.prototype.toString = function toString () {
  var length = this.length | 0
  if (length === 0) return ''
  if (arguments.length === 0) return utf8Slice(this, 0, length)
  return slowToString.apply(this, arguments)
}

Buffer.prototype.equals = function equals (b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
  if (this === b) return true
  return Buffer.compare(this, b) === 0
}

Buffer.prototype.inspect = function inspect () {
  var str = ''
  var max = exports.INSPECT_MAX_BYTES
  if (this.length > 0) {
    str = this.toString('hex', 0, max).match(/.{2}/g).join(' ')
    if (this.length > max) str += ' ... '
  }
  return '<Buffer ' + str + '>'
}

Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
  if (!Buffer.isBuffer(target)) {
    throw new TypeError('Argument must be a Buffer')
  }

  if (start === undefined) {
    start = 0
  }
  if (end === undefined) {
    end = target ? target.length : 0
  }
  if (thisStart === undefined) {
    thisStart = 0
  }
  if (thisEnd === undefined) {
    thisEnd = this.length
  }

  if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
    throw new RangeError('out of range index')
  }

  if (thisStart >= thisEnd && start >= end) {
    return 0
  }
  if (thisStart >= thisEnd) {
    return -1
  }
  if (start >= end) {
    return 1
  }

  start >>>= 0
  end >>>= 0
  thisStart >>>= 0
  thisEnd >>>= 0

  if (this === target) return 0

  var x = thisEnd - thisStart
  var y = end - start
  var len = Math.min(x, y)

  var thisCopy = this.slice(thisStart, thisEnd)
  var targetCopy = target.slice(start, end)

  for (var i = 0; i < len; ++i) {
    if (thisCopy[i] !== targetCopy[i]) {
      x = thisCopy[i]
      y = targetCopy[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
  // Empty buffer means no match
  if (buffer.length === 0) return -1

  // Normalize byteOffset
  if (typeof byteOffset === 'string') {
    encoding = byteOffset
    byteOffset = 0
  } else if (byteOffset > 0x7fffffff) {
    byteOffset = 0x7fffffff
  } else if (byteOffset < -0x80000000) {
    byteOffset = -0x80000000
  }
  byteOffset = +byteOffset  // Coerce to Number.
  if (isNaN(byteOffset)) {
    // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
    byteOffset = dir ? 0 : (buffer.length - 1)
  }

  // Normalize byteOffset: negative offsets start from the end of the buffer
  if (byteOffset < 0) byteOffset = buffer.length + byteOffset
  if (byteOffset >= buffer.length) {
    if (dir) return -1
    else byteOffset = buffer.length - 1
  } else if (byteOffset < 0) {
    if (dir) byteOffset = 0
    else return -1
  }

  // Normalize val
  if (typeof val === 'string') {
    val = Buffer.from(val, encoding)
  }

  // Finally, search either indexOf (if dir is true) or lastIndexOf
  if (Buffer.isBuffer(val)) {
    // Special case: looking for empty string/buffer always fails
    if (val.length === 0) {
      return -1
    }
    return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
  } else if (typeof val === 'number') {
    val = val & 0xFF // Search for a byte value [0-255]
    if (Buffer.TYPED_ARRAY_SUPPORT &&
        typeof Uint8Array.prototype.indexOf === 'function') {
      if (dir) {
        return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
      } else {
        return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset)
      }
    }
    return arrayIndexOf(buffer, [ val ], byteOffset, encoding, dir)
  }

  throw new TypeError('val must be string, number or Buffer')
}

function arrayIndexOf (arr, val, byteOffset, encoding, dir) {
  var indexSize = 1
  var arrLength = arr.length
  var valLength = val.length

  if (encoding !== undefined) {
    encoding = String(encoding).toLowerCase()
    if (encoding === 'ucs2' || encoding === 'ucs-2' ||
        encoding === 'utf16le' || encoding === 'utf-16le') {
      if (arr.length < 2 || val.length < 2) {
        return -1
      }
      indexSize = 2
      arrLength /= 2
      valLength /= 2
      byteOffset /= 2
    }
  }

  function read (buf, i) {
    if (indexSize === 1) {
      return buf[i]
    } else {
      return buf.readUInt16BE(i * indexSize)
    }
  }

  var i
  if (dir) {
    var foundIndex = -1
    for (i = byteOffset; i < arrLength; i++) {
      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
        if (foundIndex === -1) foundIndex = i
        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize
      } else {
        if (foundIndex !== -1) i -= i - foundIndex
        foundIndex = -1
      }
    }
  } else {
    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength
    for (i = byteOffset; i >= 0; i--) {
      var found = true
      for (var j = 0; j < valLength; j++) {
        if (read(arr, i + j) !== read(val, j)) {
          found = false
          break
        }
      }
      if (found) return i
    }
  }

  return -1
}

Buffer.prototype.includes = function includes (val, byteOffset, encoding) {
  return this.indexOf(val, byteOffset, encoding) !== -1
}

Buffer.prototype.indexOf = function indexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, true)
}

Buffer.prototype.lastIndexOf = function lastIndexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, false)
}

function hexWrite (buf, string, offset, length) {
  offset = Number(offset) || 0
  var remaining = buf.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }

  // must be an even number of digits
  var strLen = string.length
  if (strLen % 2 !== 0) throw new TypeError('Invalid hex string')

  if (length > strLen / 2) {
    length = strLen / 2
  }
  for (var i = 0; i < length; ++i) {
    var parsed = parseInt(string.substr(i * 2, 2), 16)
    if (isNaN(parsed)) return i
    buf[offset + i] = parsed
  }
  return i
}

function utf8Write (buf, string, offset, length) {
  return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
}

function asciiWrite (buf, string, offset, length) {
  return blitBuffer(asciiToBytes(string), buf, offset, length)
}

function latin1Write (buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length)
}

function base64Write (buf, string, offset, length) {
  return blitBuffer(base64ToBytes(string), buf, offset, length)
}

function ucs2Write (buf, string, offset, length) {
  return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
}

Buffer.prototype.write = function write (string, offset, length, encoding) {
  // Buffer#write(string)
  if (offset === undefined) {
    encoding = 'utf8'
    length = this.length
    offset = 0
  // Buffer#write(string, encoding)
  } else if (length === undefined && typeof offset === 'string') {
    encoding = offset
    length = this.length
    offset = 0
  // Buffer#write(string, offset[, length][, encoding])
  } else if (isFinite(offset)) {
    offset = offset | 0
    if (isFinite(length)) {
      length = length | 0
      if (encoding === undefined) encoding = 'utf8'
    } else {
      encoding = length
      length = undefined
    }
  // legacy write(string, encoding, offset, length) - remove in v0.13
  } else {
    throw new Error(
      'Buffer.write(string, encoding, offset[, length]) is no longer supported'
    )
  }

  var remaining = this.length - offset
  if (length === undefined || length > remaining) length = remaining

  if ((string.length > 0 && (length < 0 || offset < 0)) || offset > this.length) {
    throw new RangeError('Attempt to write outside buffer bounds')
  }

  if (!encoding) encoding = 'utf8'

  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'hex':
        return hexWrite(this, string, offset, length)

      case 'utf8':
      case 'utf-8':
        return utf8Write(this, string, of