LFIB4.js

import Mash from './Mash';

// From http://baagoe.com/en/RandomMusings/javascript/
export default function LFIB4() {
  // George Marsaglia's LFIB4,
  //http://groups.google.com/group/sci.crypt/msg/eb4ddde782b17051
  var args = Array.prototype.slice.call(arguments);
  var k0 = 0,
    k1 = 58,
    k2 = 119,
    k3 = 178;

  var s = [];

  var mash = Mash();
  if (args.length === 0) {
    args = [+new Date()];
  }
  for (var j = 0; j < 256; j++) {
    s[j] = mash(' ');
    s[j] -= mash(' ') * 4.76837158203125e-7; // 2^-21
    if (s[j] < 0) {
      s[j] += 1;
    }
  }
  for (var i = 0; i < args.length; i++) {
    for (var j = 0; j < 256; j++) {
      s[j] -= mash(args[i]);
      s[j] -= mash(args[i]) * 4.76837158203125e-7; // 2^-21
      if (s[j] < 0) {
        s[j] += 1;
      }
    }
  }
  mash = null;

  var random = function () {
    var x;

    k0 = (k0 + 1) & 255;
    k1 = (k1 + 1) & 255;
    k2 = (k2 + 1) & 255;
    k3 = (k3 + 1) & 255;

    x = s[k0] - s[k1];
    if (x < 0) {
      x += 1;
    }
    x -= s[k2];
    if (x < 0) {
      x += 1;
    }
    x -= s[k3];
    if (x < 0) {
      x += 1;
    }

    return s[k0] = x;
  }

  random.uint32 = function () {
    return random() * 0x100000000 >>> 0; // 2^32
  };
  random.fract53 = random;
  random.version = 'LFIB4 0.9';
  random.args = args;

  return random;
};