xethya-random-bbs/dist/index.umd.js

An implementation of the Blum Blum Shub PRNG.

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('babel-runtime/core-js/object/assign'), require('babel-runtime/helpers/classCallCheck'), require('babel-runtime/helpers/createClass')) :
  typeof define === 'function' && define.amd ? define(['exports', 'babel-runtime/core-js/object/assign', 'babel-runtime/helpers/classCallCheck', 'babel-runtime/helpers/createClass'], factory) :
  (factory((global.xethya-random-bbs = global.xethya-random-bbs || {}),global._Object$assign,global._classCallCheck,global._createClass));
}(this, function (exports,_Object$assign,_classCallCheck,_createClass) { 'use strict';

  _Object$assign = 'default' in _Object$assign ? _Object$assign['default'] : _Object$assign;
  _classCallCheck = 'default' in _classCallCheck ? _classCallCheck['default'] : _classCallCheck;
  _createClass = 'default' in _createClass ? _createClass['default'] : _createClass;

  /**
   * xethya-random-bbs
   *
   * Copyright © 2016 Joel A. Villarreal Bertoldi. All rights reserved.
   *
   * This source code is licensed under the MIT license found in the
   * LICENSE.txt file in the root directory of this source tree.
   */

  /**
   * Default constant value for setting up the BBS PRNG.
   * P must be a prime number.
   * @type {Number}
   */
  var P = 87566873;

  /**
   * Default constant value for setting up the BBS PRNG.
   * Q must be a prime number.
   * @type {Number}
   */
  var Q = 5631179;

  /**
   * A list of default seed values, tested to be evenly distributed.
   * @see  http://wiki.fib.upc.es/sim/index.php/Blum_Blum_Shub#Tests
   * @type {Array.<Number>}
   */
  var DefaultSeeds = [193945, 740191, 191];

  /**
   * Instantiates a Blum Blum Shub PRNG.
   */

  var BlumBlumShub = function () {

    /**
     * Initializes the generator.
     *
     * @param  {Number} p    A prime value (defaults to P).
     * @param  {Number} q    A prime value (defaults to Q).
     * @param  {Number} seedNumber A seed number to feed the generator (defaults to any value
     *                       in DefaultSeeds).
     * @constructor
     */
    function BlumBlumShub(settings) {
      _classCallCheck(this, BlumBlumShub);

      var defaults = {
        p: P,
        q: Q,
        seedNumber: null
      };

      this.settings = _Object$assign({}, defaults, settings);

      var seedNumber = this.settings.seedNumber;
      var _settings = this.settings;
      var p = _settings.p;
      var q = _settings.q;


      if (seedNumber) {
        seedNumber = Math.abs(seedNumber);
      } else {
        seedNumber = DefaultSeeds[Math.floor(Math.random() * DefaultSeeds.length)];
      }

      this.seedNumber = seedNumber;
      this.randomIndex = seedNumber;
      this.M = p * q;
      this.P = p;
      this.Q = q;
    }

    /**
     * Determines if the generator works better by being reinstantiated after
     * every generated number.
     *
     * @return {Boolean}
     * @static
     */


    _createClass(BlumBlumShub, [{
      key: 'generateRandom',


      /**
       * Generates a pseudo-random number and updates the seed for a next roll.
       * Number is always between 0 and 1.
       *
       * @return {Number}
       */
      value: function generateRandom() {
        var r = this.randomIndex * this.randomIndex % this.M;
        this.randomIndex = r;
        return Math.abs(r / this.M);
      }

      /**
       * Same as `generateRandom()`, but converts the number to an Integer.
       *
       * @return {Number}
       */

    }, {
      key: 'generateRandomInteger',
      value: function generateRandomInteger() {
        return Number(this.generateRandom().toString().replace(/\./, ''));
      }
    }], [{
      key: 'recommendsToReinstantiate',
      value: function recommendsToReinstantiate() {
        return false;
      }
    }]);

    return BlumBlumShub;
  }();

  exports.P = P;
  exports.Q = Q;
  exports.DefaultSeeds = DefaultSeeds;
  exports.BlumBlumShub = BlumBlumShub;

  Object.defineProperty(exports, '__esModule', { value: true });

}));
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