/*SPEL virtual machine
Copyright (C) 2016  Logan Streondj

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

contact: streondj at gmail dot com
*/
/*  Written in 2015 by Sebastiano Vigna (vigna@acm.org)

To the extent possible under law, the author has dedicated all copyright
and related and neighboring rights to this software to the public domain
worldwide. This software is distributed without any warranty.

See <http://creativecommons.org/publicdomain/zero/1.0/>. */

#include <stdint.h>
#include "prng.h"

/* This is a fixed-increment version of Java 8's SplittableRandom generator
   See http://dx.doi.org/10.1145/2714064.2660195 and
   http://docs.oracle.com/javase/8/docs/api/java/util/SplittableRandom.html

   It is a very fast generator passing BigCrush, and it can be useful if
   for some reason you absolutely want 64 bits of state; otherwise, we
   rather suggest to use a xoroshiro128+ (for moderately parallel
   computations) or xorshift1024* (for massively parallel computations)
   generator. */

uint64_t splitMix64(uint64_t *seed) {
  uint64_t z = (*seed += UINT64_C(0x9E3779B97F4A7C15));
  z = (z ^ (z >> 30)) * UINT64_C(0xBF58476D1CE4E5B9);
  z = (z ^ (z >> 27)) * UINT64_C(0x94D049BB133111EB);
  return z ^ (z >> 31);
}