gistfile1.js

/*!
 * socket.io-node
 * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
 * MIT Licensed
 */

/**
 * Module dependencies.
 */

/**
 * Packet types.
 */

var packets = exports.packets = {
      'disconnect': 0
    , 'connect': 1
    , 'heartbeat': 2
    , 'message': 3
    , 'json': 4
    , 'event': 5
    , 'ack': 6
    , 'error': 7
    , 'noop': 8
  }
  , packetslist = Object.keys(packets);

/**
 * Errors reasons.
 */

var reasons = exports.reasons = {
      'transport not supported': 0
    , 'client not handshaken': 1
    , 'unauthorized': 2
  }
  , reasonslist = Object.keys(reasons);

/**
 * Errors advice.
 */

var advice = exports.advice = {
      'reconnect': 0
  }
  , advicelist = Object.keys(advice);

/**
 * Encodes a packet.
 *
 * @api private
 */
 
var encoder =  {
  'message': function(data, packet) {
    if (packet.data !== '')
      data = packet.data;
    return data;
  },
  'event': function(data, packet) {
    var ev = { name: packet.name };
    if (packet.args && packet.args.length) {
      ev.args = packet.args;
    }
    data = JSON.stringify(ev);
    return data;
  },
  'json': function(data, packet) {
    data = JSON.stringify(packet.data);
    return data;
  },
  'ack': function(data, packet) {
    data = packet.ackId
      + (packet.args && packet.args.length
          ? '+' + JSON.stringify(packet.args) : '');
    return data;
  },
  'connect': function(data, packet) {
    if (packet.qs)
      data = packet.qs;
    return data;
  },
  'error': function(data, packet) {
    var reason = packet.reason ? reasons[packet.reason] : ''
      , adv = packet.advice ? advice[packet.advice] : ''
 
    if (reason !== '' || adv !== '')
      data = reason + (adv !== '' ? ('+' + adv) : '')
    return data;
  }
}

exports.encodePacket = function (packet) {
  var type = packets[packet.type]
    , id = packet.id || ''
    , endpoint = packet.endpoint || ''
    , ack = packet.ack
    , data = null;

   data = encoder[packet.type](data, packet);

  // construct packet with required fragments
  var encoded = [
      type
    , id + (ack == 'data' ? '+' : '')
    , endpoint
  ];

  // data fragment is optional
  if (data !== null && data !== undefined)
    encoded.push(data);

  return encoded.join(':');
};

/**
 * Encodes multiple messages (payload).
 *
 * @param {Array} messages
 * @api private
 */

exports.encodePayload = function (packets) {
  var decoded = '';

  if (packets.length == 1)
    return packets[0];

  for (var i = 0, l = packets.length; i < l; i++) {
    var packet = packets[i];
    decoded += '\ufffd' + packet.length + '\ufffd' + packets[i]
  }

  return decoded;
};

/**
 * Decodes a packet
 *
 * @api private
 */

var regexp = /([^:]+):([0-9]+)?(\+)?:([^:]+)?:?([\s\S]*)?/;
var parse = JSON.parse;
var decoder =  {
  'message': function(data, packet) {
    packet.data = data || '';
  },
  'event': function(data, packet) {
    try {
      var pieces = parse(data);
      packet.name = pieces.name;
      packet.args = pieces.args;
    } catch (e) { }
    packet.args = packet.args || [];
  },
  'json': function(data, packet) {
    try {
      packet.data = parse(data);
    } catch (e) { }
  },
  'connect': function(data, packet) {
    packet.qs = data || '';
  },
  'ack': function(data, packet) {
    var pieces = data.match(/^([0-9]+)(\+)?(.*)/);
    if (pieces) {
      packet.ackId = pieces[1];
      packet.args = [];

      if (pieces[3]) {
        try {
          packet.args = pieces[3] ? parse(pieces[3]) : [];
        } catch (e) { }
      }
    }
  },
  'error': function(data, packet) {
    var pieces = data.split('+');
    packet.reason = reasonslist[pieces[0]] || '';
    packet.advice = advicelist[pieces[1]] || '';
  }
}

exports.decodePacket = function (data) {
  var pieces = data.match(regexp);

  if (!pieces) return {};

  var id = pieces[2] || ''
    , data = pieces[5] || ''
    , packet = {
          type: packetslist[pieces[1]]
        , endpoint: pieces[4] || ''
      };

  // whether we need to acknowledge the packet
  if (id) {
    packet.id = id;
    if (pieces[3])
      packet.ack = 'data';
    else
      packet.ack = true;
  }

  // handle different packet types
  decoder[packet.type](data, packet);

  return packet;
};

/**
 * Decodes data payload. Detects multiple messages
 *
 * @return {Array} messages
 * @api public
 */

exports.decodePayload = function (data) {
  if (undefined == data || null == data) {
    return [];
  }

  if (data[0] == '\ufffd') {
    var ret = [];

    for (var i = 1, length = ''; i < data.length; i++) {
      if (data[i] == '\ufffd') {
        ret.push(exports.decodePacket(data.substr(i + 1).substr(0, length)));
        i += Number(length) + 1;
        length = '';
      } else {
        length += data[i];
      }
    }

    return ret;
  } else {
    return [exports.decodePacket(data)];
  }
};

my experimental changes

Executed benchmark encoding (string)
Count (80769), Cycles (95), Elapsed (5.036), Hz (1503795.6932021)
Executed benchmark encoding (event+ack)
Count (37727), Cycles (96), Elapsed (5.029), Hz (714417.3243181611)
Executed benchmark encoding (event+data)
Count (16332), Cycles (100), Elapsed (5.051), Hz (319930.5813885676)
Executed benchmark encoding (payload)
Count (9851), Cycles (100), Elapsed (5.051), Hz (194113.86759713356)
Executed benchmark decoding (string)
Count (106126), Cycles (100), Elapsed (5.001), Hz (2101277.3588654296)
Executed benchmark decoding (event)
Count (53514), Cycles (100), Elapsed (5.02), Hz (1058395.1330354088)
Executed benchmark decoding (event+ack)
Count (47672), Cycles (100), Elapsed (5.018), Hz (938549.735871924)
Executed benchmark decoding (event+data)
Count (27802), Cycles (100), Elapsed (5.032), Hz (548953.1866758841)
Executed benchmark decoding (payload)
Count (7937), Cycles (100), Elapsed (5.006), Hz (157456.94950931493)

original

Executed benchmark encoding (string)
Count (69519), Cycles (100), Elapsed (5.038), Hz (1372022.3509649534)
Executed benchmark encoding (event+ack)
Count (36560), Cycles (99), Elapsed (5.01), Hz (716103.8763114816)
Executed benchmark encoding (event+data)
Count (17507), Cycles (100), Elapsed (5.03), Hz (345261.3699044089)
Executed benchmark encoding (payload)
Count (10575), Cycles (100), Elapsed (5.024), Hz (209442.11976789756)
Executed benchmark decoding (string)
Count (93225), Cycles (101), Elapsed (5.05), Hz (1842997.7012547196)
Executed benchmark decoding (event)
Count (51114), Cycles (95), Elapsed (5.039), Hz (956307.723505352)
Executed benchmark decoding (event+ack)
Count (45895), Cycles (100), Elapsed (5.02), Hz (906246.2343380426)
Executed benchmark decoding (event+data)
Count (25581), Cycles (100), Elapsed (5.022), Hz (505888.965932063)
Executed benchmark decoding (payload)
Count (8067), Cycles (101), Elapsed (5.039), Hz (160269.65544290532)