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