xs_yarandom.h

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/* xscreensaver, Copyright (c) 1997 by Jamie Zawinski <[e-mail]>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation.  No representations are made about the suitability of this
 * software for any purpose.  It is provided "as is" without express or 
 * implied warranty.
 */

#ifndef __YARANDOM_H__
#define __YARANDOM_H__

#undef random
#undef rand
#undef drand48
#undef srandom
#undef srand
#undef srand48
#undef frand

#ifdef VMS
# include "vms-gtod.h"
#endif

/* #define random()   ya_random()
 #define srandom(i) ya_rand_init(0) */

extern unsigned int ya_random (void);
extern void ya_rand_init (unsigned int);


#if defined (__GNUC__) && (__GNUC__ >= 2)
 /* Implement frand using GCC's statement-expression extension. */

# define frand(f)							\
  ({ double tmp = (((double) random()) /				\
		   (((double) ((unsigned int)~0)) / ((double) (f))));	\
     tmp < 0 ? (-tmp) : tmp; })

#else /* not GCC2 - implement frand using a global variable.*/

static double _frand_tmp_;
# define frand(f)							\
  (_frand_tmp_ = (((double) random()) / 				\
		  (((double) ((unsigned int)~0)) / ((double) (f)))),	\
   _frand_tmp_ < 0 ? (-_frand_tmp_) : _frand_tmp_)

#endif /* not GCC2 */

#endif /* __YARANDOM_H__ */