From eb83c5250e10c1260c0dc2e58b2cea792f93decf Mon Sep 17 00:00:00 2001
From: Gary Kwong <gary@rumblingedge.com>
Date: Thu, 6 Apr 2017 12:22:57 +0200
Subject: [PATCH] Add jruderman's version of Mersenne Twister from funfuzz rev
 2ab19c2b.

---
 random/mersennetwister.js | 114 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 random/mersennetwister.js

diff --git a/random/mersennetwister.js b/random/mersennetwister.js
new file mode 100644
index 0000000..6af13ae
--- /dev/null
+++ b/random/mersennetwister.js
@@ -0,0 +1,114 @@
+// this program is a JavaScript version of Mersenne Twister, with concealment and encapsulation in class,
+// an almost straight conversion from the original program, mt19937ar.c,
+// translated by y. okada on July 17, 2006.
+
+// Changes by Jesse Ruderman:
+//   * Use intish/int32 rather than uint32 for intermediate calculations
+//     (see https://bugzilla.mozilla.org/show_bug.cgi?id=883748#c1)
+//   * Added functions for exporting/importing the entire PRNG state
+//   * Removed parts not needed for fuzzing
+
+// in this program, procedure descriptions and comments of original source code were not removed.
+// lines commented with //c// were originally descriptions of c procedure. and a few following lines are appropriate JavaScript descriptions.
+// lines commented with /* and */ are original comments.
+// lines commented with // are additional comments in this JavaScript version.
+// before using this version, create at least one instance of MersenneTwister19937 class, and initialize the each state, given below in c comments, of all the instances.
+
+/*
+   A C-program for MT19937, with initialization improved 2002/1/26.
+   Coded by Takuji Nishimura and Makoto Matsumoto.
+
+   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+     1. Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+
+     2. Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+
+     3. The names of its contributors may not be used to endorse or promote
+        products derived from this software without specific prior written
+        permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+   Any feedback is very welcome.
+   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
+*/
+
+
+function MersenneTwister19937()
+{
+  const N = 624;
+  const M = 397;
+  const MAG01 = new Int32Array([0, 0x9908b0df]);
+
+  var mt = new Int32Array(N);   /* the array for the state vector */
+  var mti = 625;
+
+  this.seed = function (s) {
+    mt[0] = s | 0;
+    for (mti=1; mti<N; mti++) {
+      mt[mti] = Math.imul(1812433253, mt[mti-1] ^ (mt[mti-1] >>> 30)) + mti;
+    }
+  };
+
+  this.export_state = function() { return [mt, mti]; };
+  this.import_state = function(s) { mt = s[0]; mti = s[1]; };
+  this.export_mta = function() { return mt; };
+  this.import_mta = function(_mta) { mt = _mta; };
+  this.export_mti = function() { return mti; };
+  this.import_mti = function(_mti) { mti = _mti; };
+
+  function mag01(y)
+  {
+    return MAG01[y & 0x1];
+  }
+
+  this.int32 = function () {
+    var y;
+    var kk;
+
+    if (mti >= N) { /* generate N words at one time */
+      for (kk=0;kk<N-M;kk++) {
+        y = ((mt[kk]&0x80000000)|(mt[kk+1]&0x7fffffff));
+        mt[kk] = (mt[kk+M] ^ (y >>> 1) ^ mag01(y));
+      }
+      for (;kk<N-1;kk++) {
+        y = ((mt[kk]&0x80000000)|(mt[kk+1]&0x7fffffff));
+        mt[kk] = (mt[kk+(M-N)] ^ (y >>> 1) ^ mag01(y));
+      }
+      y = ((mt[N-1]&0x80000000)|(mt[0]&0x7fffffff));
+      mt[N-1] = (mt[M-1] ^ (y >>> 1) ^ mag01(y));
+      mti = 0;
+    }
+
+    y = mt[mti++];
+
+    /* Tempering */
+    y = y ^ (y >>> 11);
+    y = y ^ ((y << 7) & 0x9d2c5680);
+    y = y ^ ((y << 15) & 0xefc60000);
+    y = y ^ (y >>> 18);
+
+    return y;
+  };
+}