fingerprint.js

/*
* fingerprintJS 0.1 - Fast browser fingerprint library
* https://github.com/Valve/fingerprintJS
* Copyright (c) 2013 Valentin Vasilyev (iamvalentin@gmail.com)
* Licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) license.
*/
function Fingerprint(hasher){
  var nativeForEach = Array.prototype.forEach;
  var nativeMap = Array.prototype.map;
  this.each = function(obj, iterator, context) {
    if (obj == null) return;
    if (nativeForEach && obj.forEach === nativeForEach) {
      obj.forEach(iterator, context);
    } else if (obj.length === +obj.length) {
      for (var i = 0, l = obj.length; i < l; i++) {
        if (iterator.call(context, obj[i], i, obj) === {}) return;
      }
    } else {
      for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
          if (iterator.call(context, obj[key], key, obj) === {}) return;
        }
      }
    }
  };
  this.map = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
    this.each(obj, function(value, index, list) {
      results[results.length] = iterator.call(context, value, index, list);
    });
    return results;
  };

  if(hasher){
    this.hasher = hasher;
  }
}

Fingerprint.prototype = {

  get: function(){
    keys = [];
    keys.push(navigator.userAgent);
    keys.push([screen.height, screen.width, screen.colorDepth].join('x'));
    keys.push(new Date().getTimezoneOffset());
    keys.push(!!window.sessionStorage);
    keys.push(!!window.localStorage);
    var pluginsString = this.map(navigator.plugins, function(p){
      var mimeTypes = this.map(p, function(mt){
        return [mt.type, mt.suffixes].join('~');
      }).join(',');
      return [p.name, p.description, mimeTypes].join('::');
    }, this).join(';');
    keys.push(pluginsString);
    if(this.hasher){
      return this.hasher(keys.join('###'), 31);
    } else {
      return this.murmurhash3_32_gc(keys.join('###'), 31);
    }
  },

  /**
   * JS Implementation of MurmurHash3 (r136) (as of May 20, 2011)
   * 
   * @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
   * @see http://github.com/garycourt/murmurhash-js
   * @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
   * @see http://sites.google.com/site/murmurhash/
   * 
   * @param {string} key ASCII only
   * @param {number} seed Positive integer only
   * @return {number} 32-bit positive integer hash 
   */

  murmurhash3_32_gc: function(key, seed) {
    var remainder, bytes, h1, h1b, c1, c1b, c2, c2b, k1, i;
    
    remainder = key.length & 3; // key.length % 4
    bytes = key.length - remainder;
    h1 = seed;
    c1 = 0xcc9e2d51;
    c2 = 0x1b873593;
    i = 0;
    
    while (i < bytes) {
        k1 = 
          ((key.charCodeAt(i) & 0xff)) |
          ((key.charCodeAt(++i) & 0xff) << 8) |
          ((key.charCodeAt(++i) & 0xff) << 16) |
          ((key.charCodeAt(++i) & 0xff) << 24);
      ++i;
      
      k1 = ((((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16))) & 0xffffffff;
      k1 = (k1 << 15) | (k1 >>> 17);
      k1 = ((((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16))) & 0xffffffff;

      h1 ^= k1;
          h1 = (h1 << 13) | (h1 >>> 19);
      h1b = ((((h1 & 0xffff) * 5) + ((((h1 >>> 16) * 5) & 0xffff) << 16))) & 0xffffffff;
      h1 = (((h1b & 0xffff) + 0x6b64) + ((((h1b >>> 16) + 0xe654) & 0xffff) << 16));
    }
    
    k1 = 0;
    
    switch (remainder) {
      case 3: k1 ^= (key.charCodeAt(i + 2) & 0xff) << 16;
      case 2: k1 ^= (key.charCodeAt(i + 1) & 0xff) << 8;
      case 1: k1 ^= (key.charCodeAt(i) & 0xff);
      
      k1 = (((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16)) & 0xffffffff;
      k1 = (k1 << 15) | (k1 >>> 17);
      k1 = (((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16)) & 0xffffffff;
      h1 ^= k1;
    }
    
    h1 ^= key.length;

    h1 ^= h1 >>> 16;
    h1 = (((h1 & 0xffff) * 0x85ebca6b) + ((((h1 >>> 16) * 0x85ebca6b) & 0xffff) << 16)) & 0xffffffff;
    h1 ^= h1 >>> 13;
    h1 = ((((h1 & 0xffff) * 0xc2b2ae35) + ((((h1 >>> 16) * 0xc2b2ae35) & 0xffff) << 16))) & 0xffffffff;
    h1 ^= h1 >>> 16;

    return h1 >>> 0;
  }
}