rand.h

   1 // Copyright 2006 David Hilvert <dhilvert@auricle.dyndns.org>,
   2 //                              <dhilvert@ugcs.caltech.edu>
   3 //                              <dhilvert@gmail.com>
   4
   5 /*  This file is part of the Anti-Lamenessing Engine.
   6
   7     The Anti-Lamenessing Engine is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 3 of the License, or
  10     (at your option) any later version.
  11
  12     The Anti-Lamenessing Engine is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with the Anti-Lamenessing Engine; if not, write to the Free Software
  19     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 */
  21
  22 /*
  23  * rand.h: random number generator class.
  24  */
  25
  26 #ifndef __rand_h__
  27 #define __rand_h__
  28
  29 #include <assert.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #ifdef USE_PTHREAD
  35 #include <pthread.h>
  36 #endif
  37
  38 class rng_t {
  39 #ifdef USE_PTHREAD
  40         static pthread_mutex_t rand_mutex;
  41 #endif
  42         union {
  43                 unsigned int state_ui;
  44                 unsigned short state_us3[3];
  45         } state_vars;
  46 public:
  47
  48         void seed(unsigned int s) {
  49 #ifdef USE_PTHREAD
  50                 state_vars.state_us3[0] = (unsigned short) s;
  51                 state_vars.state_us3[1] = 0;
  52                 state_vars.state_us3[2] = 0;
  53                 state_vars.state_ui = s;
  54 #else
  55                 srand(s);
  56 #endif
  57         }
  58         int get() {
  59 #ifdef USE_PTHREAD
  60 #if HAVE_NRAND48
  61                 return (int) nrand48(state_vars.state_us3) % RAND_MAX;
  62 #elif HAVE_RAND_R
  63                 return rand_r(&state_vars.state_ui);
  64 #else
  65                 int result;
  66
  67                 pthread_mutex_lock(&rand_mutex);
  68                 srand(state_vars.state_ui);
  69                 result = rand();
  70                 pthread_mutex_unlock(&rand_mutex);
  71
  72                 state_vars.state_ui = (unsigned int) result;
  73
  74                 return result;
  75 #endif
  76 #else
  77                 return rand();
  78 #endif
  79         }
  80 };
  81
  82 #endif