/simpletypesystem/trunk

/*

Copyright (c) 2013-2017 Gustav Hartvigsson

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

THE SOFTWARE.

 */

/*

Adaptation of

http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/VERSIONS/C-LANG/mt19937-64.c

with the following license:

Copyright (C) 2004, 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.

*/

#include "Random.h"

#include "primes.h"

#include <time.h>

#define NN 312

#define MM 156

#define MATRIX_A 0xB5026F5AA96619E9ULL

#define UM 0xFFFFFFFF80000000ULL /* Most significant 33 bits */

#define LM 0x7FFFFFFFULL /* Least significant 31 bits */

struct SRandom {

  sulong seed;

  sulong current;

  size_t index;

  size_t itt;

  sulong * list;

};

void

_s_internal_random_init (SRandom * self);

SRandom *

s_random_new () {

  return s_random_new_with_seed ((slong) time (NULL));

}

SRandom *

s_random_new_with_seed (sulong seed) {

  SRandom * self = s_malloc (sizeof (SRandom));

  self->seed = seed;

  self->list = s_calloc(NN, sizeof (sulong));

  self->itt = NN+1;

  return self;

}

void

s_random_reseed (SRandom * self, sulong seed) {

  /* We just have to re-set these things. */

  self->seed = seed;

  self->itt = NN+1;

}

sulong

s_random_next (SRandom * self) {

  size_t i;

  slong x;

  static slong mag01[2]={0ULL, MATRIX_A};

  if (self->itt >= NN) {

    if (self->itt == NN+1) {

      _s_internal_random_init (self);

    }

    for (i = 0; i < NN - MM; i++) {

      x = (self->list[i] & UM) | (self->list[i+1] & LM);

      self->list[i] = self->list[i + MM] ^

                                (x >> 1) ^

                mag01[(sint)(x & 1ULL)];

    }

    for (/* i */; i < NN - 1; i++) {

      x = (self->list[i] & UM) | (self->list[i + 1] & LM);

      self->list[i] = self->list[i + (MM - NN)] ^

                                       (x >> 1) ^

                        mag01[(sint)(x & 1ULL)];

    }

    x = (self->list[NN - 1] & UM) | (self->list[0] & LM);

    self->list[NN - 1] = self->list[MM - 1] ^

                                   (x >> 1) ^

                   mag01[(sint) (x & 1ULL)];

    self->itt = 0;

  }

  self->current = self->list[self->itt];

  x = self->list[self->itt++];

  x ^= (x >> 29) & 0x5555555555555555ULL;

  x ^= (x << 17) & 0x71D67FFFEDA60000ULL;

  x ^= (x << 37) & 0xFFF7EEE000000000ULL;

  x ^= (x >> 43);

  return x;

}

sulong

s_random_current (SRandom * self) {

  return self->current;

}

slong

s_random_next_long (SRandom * self) {

  return (s_random_next (self) >> 1); 

}

sdouble

s_random_next_real (SRandom * self) {

  return (s_random_next (self) >> 11) * (1.0/9007199254740991.0);

}

slong

s_random_current_long (SRandom * self) {

  sulong current = self->current;

  return (current >> 1); 

}

sdouble

s_random_current_real (SRandom * self) {

  sulong current = self->current;

  return (current >> 11) * (1.0/9007199254740991.0);

}

void

_s_internal_random_init (SRandom * self) {

  self->list[0] = self->seed;

  for (self->itt = 0; self->itt < NN; self->itt++) {

    self->list[self->itt] =

       (6364136223846793005ULL * (self->list[self->itt - 1] ^

          (self->list[self->itt - 1] >> 62)) + self->itt);

  }

}

#if 0

slong

s_random_get_entropy () {

  #ifdef _WIN32

  #elif __unix__

  #else

    #error "We can't get at an entropy pool?"

  #endif

}

#endif