wmMatrix/yarandom.h

   1 /* xscreensaver, Copyright (c) 1997, 1998 by Jamie Zawinski <jwz@jwz.org>
   2  *
   3  * Permission to use, copy, modify, distribute, and sell this software and its
   4  * documentation for any purpose is hereby granted without fee, provided that
   5  * the above copyright notice appear in all copies and that both that
   6  * copyright notice and this permission notice appear in supporting
   7  * documentation.  No representations are made about the suitability of this
   8  * software for any purpose.  It is provided "as is" without express or
   9  * implied warranty.
  10  */
  11
  12 #ifndef __YARANDOM_H__
  13 #define __YARANDOM_H__
  14
  15 #undef random
  16 #undef rand
  17 #undef drand48
  18 #undef srandom
  19 #undef srand
  20 #undef srand48
  21 #undef frand
  22 #undef RAND_MAX
  23
  24 #ifdef VMS
  25 #include "vms-gtod.h"
  26 #endif
  27
  28 #define random()   ya_random()
  29 #define srandom(i) ya_rand_init(0)
  30 #define RAND_MAX   0x7FFFFFFF
  31
  32 extern unsigned int ya_random(void);
  33 extern void ya_rand_init(unsigned int);
  34
  35 #if defined (__GNUC__) && (__GNUC__ >= 2)
  36  /* Implement frand using GCC's statement-expression extension. */
  37
  38 #define frand(f)                                                        \
  39   ({ double tmp = (((double) random()) /                                \
  40                    (((double) ((unsigned int)~0)) / ((double) (f))));   \
  41      tmp < 0 ? (-tmp) : tmp; })
  42
  43 #else                                                   /* not GCC2 - implement frand using a global variable. */
  44
  45 static double _frand_tmp_;
  46 #define frand(f)                                                        \
  47   (_frand_tmp_ = (((double) random()) /                                 \
  48                   (((double) ((unsigned int)~0)) / ((double) (f)))),    \
  49    _frand_tmp_ < 0 ? (-_frand_tmp_) : _frand_tmp_)
  50
  51 #endif                                                  /* not GCC2 */
  52
  53 #endif                                                  /* __YARANDOM_H__ */