/* * random.cxx * * Mersenne Twister random number generator. * From Makoto Matsumoto and Takuji Nishimura. * * Portable Windows Library * * Copyright (c) 1993-2000 Equivalence Pty. Ltd. * * The contents of this file are subject to the Mozilla Public License * Version 1.0 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See * the License for the specific language governing rights and limitations * under the License. * * The Original Code is Portable Windows Library. * * The Initial Developer of the Original Code is Equivalence Pty. Ltd. * * Based on code originally under the following license: * * This library is free software; you can redistribute it and/or    * modify it under the terms of the GNU Library General Public      * License as published by the Free Software Foundation; either     * version 2 of the License, or (at your option) any later          * version.                                                         * This library 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 Library General Public License for more details.     * You should have received a copy of the GNU Library General       * Public License along with this library; if not, write to the     * Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA    * 02111-1307  USA                                                  *  * Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura.        * When you use this, send an email to: matumoto@math.keio.ac.jp    * with an appropriate reference to your work.                      * * Contributor(s): ______________________________________. * * $Log: random.cxx,v $ * Revision 1.1  2000/02/17 12:05:02  robertj * Added better random number generator after finding major flaws in MSVCRT version. * */#ifdef __GNUC__#pragma implementation "random.h"#endif#include <ptlib.h>#include <ptclib/random.h>/* Period parameters */  #define M 397#define MATRIX_A 0x9908b0df   /* constant vector a */#define UPPER_MASK 0x80000000 /* most significant w-r bits */#define LOWER_MASK 0x7fffffff /* least significant r bits *//* Tempering parameters */   #define TEMPERING_MASK_B 0x9d2c5680#define TEMPERING_MASK_C 0xefc60000#define TEMPERING_SHIFT_U(y)  (y >> 11)#define TEMPERING_SHIFT_S(y)  (y << 7)#define TEMPERING_SHIFT_T(y)  (y << 15)#define TEMPERING_SHIFT_L(y)  (y >> 18)///////////////////////////////////////////////////////////////////////////////// PRandomPRandom::PRandom(){  SetSeed((DWORD)(time(NULL)+clock()));}PRandom::PRandom(DWORD seed){  SetSeed(seed);}void PRandom::SetSeed(DWORD seed){    /* setting initial seeds to mt[N] using         */    /* the generator Line 25 of Table 1 in          */    /* [KNUTH 1981, The Art of Computer Programming */    /*    Vol. 2 (2nd Ed.), pp102]                  */    mt[0] = seed & 0xffffffff;    for (mti = 1; mti < N; mti++)        mt[mti] = (69069 * mt[mti-1]) & 0xffffffff;}unsigned PRandom::Generate(){  unsigned long y;  static unsigned long mag01[2]={0x0, MATRIX_A};  /* mag01[x] = x * MATRIX_A  for x=0,1 */  if (mti >= N) { /* generate N words at one time */    int kk;    for (kk=0;kk<N-M;kk++) {      y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);      mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];    }    for (;kk<N-1;kk++) {      y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);      mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1];    }    y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);    mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];    mti = 0;  }  y = mt[mti++];  y ^= TEMPERING_SHIFT_U(y);  y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;  y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;  y ^= TEMPERING_SHIFT_L(y);  return y; }unsigned PRandom::Number(){  static PMutex mutex;  PWaitAndSignal wait(mutex);  static PRandom rand;  return rand;}// End Of File ///////////////////////////////////////////////////////////////