This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/os/random.c

147 lines
2.9 KiB
C
Raw Normal View History

#include "sysbits.h"
#if HAVE_TIME_H
#include <time.h>
#endif
unsigned int current_seed;
extern int rand(void);
double
Yap_random (void)
{
#if HAVE_DRAND48
return drand48();
#elif HAVE_RANDOM
/* extern long random (); */
return (((double) random ()) / 0x7fffffffL /* 2**31-1 */);
#elif HAVE_RAND
return (((double) (rand ()) / RAND_MAX));
#else
Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil,
"random not available in this configuration");
return (0.0);
#endif
}
#if HAVE_RANDOM
static Int
p_init_random_state ( USES_REGS1 )
{
register Term t0 = Deref (ARG1);
char *old, *new;
if (IsVarTerm (t0)) {
return(Yap_unify(ARG1,MkIntegerTerm((Int)current_seed)));
}
if(!IsNumTerm (t0))
return (FALSE);
if (IsIntTerm (t0))
current_seed = (unsigned int) IntOfTerm (t0);
else if (IsFloatTerm (t0))
current_seed = (unsigned int) FloatOfTerm (t0);
else
current_seed = (unsigned int) LongIntOfTerm (t0);
new = (char *) malloc(256);
old = initstate(random(), new, 256);
return Yap_unify(ARG2, MkIntegerTerm((Int)old)) &&
Yap_unify(ARG3, MkIntegerTerm((Int)new));
}
static Int
p_set_random_state ( USES_REGS1 )
{
register Term t0 = Deref (ARG1);
char *old, * new;
if (IsVarTerm (t0)) {
return FALSE;
}
if (IsIntegerTerm (t0))
new = (char *) IntegerOfTerm (t0);
else
return FALSE;
old = setstate( new );
return Yap_unify(ARG2, MkIntegerTerm((Int)old));
}
static Int
p_release_random_state ( USES_REGS1 )
{
register Term t0 = Deref (ARG1);
char *old;
if (IsVarTerm (t0)) {
return FALSE;
}
if (IsIntegerTerm (t0))
old = (char *) IntegerOfTerm (t0);
else
return FALSE;
free( old );
return TRUE;
}
#endif
static Int
Srandom ( USES_REGS1 )
{
register Term t0 = Deref (ARG1);
if (IsVarTerm (t0)) {
return(Yap_unify(ARG1,MkIntegerTerm((Int)current_seed)));
}
if(!IsNumTerm (t0))
return (FALSE);
if (IsIntTerm (t0))
current_seed = (unsigned int) IntOfTerm (t0);
else if (IsFloatTerm (t0))
current_seed = (unsigned int) FloatOfTerm (t0);
else
current_seed = (unsigned int) LongIntOfTerm (t0);
#if HAVE_SRAND48
srand48(current_seed);
#elif HAVE_SRANDOM
srandom(current_seed);
#elif HAVE_SRAND
srand(current_seed);
#endif
return (TRUE);
}
/**
* Initialize the defaulr tandom number generator.
*
* uses the process's tome call.
*
*/
void
Yap_InitRandom (void)
{
current_seed = (unsigned int) time (NULL);
#if HAVE_SRAND48
srand48 (current_seed);
#elif HAVE_SRANDOM
srandom (current_seed);
#elif HAVE_SRAND
srand (current_seed);
#endif
}
void
Yap_InitRandomPreds (void)
{
Yap_InitCPred ("srandom", 1, Srandom, SafePredFlag);
#if HAVE_RANDOM
Yap_InitCPred ("init_random_state", 3, p_init_random_state, SafePredFlag);
Yap_InitCPred ("set_random_state", 2, p_set_random_state, SafePredFlag);
Yap_InitCPred ("release_random_state", 1, p_release_random_state, SafePredFlag);
#endif
}