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yap-6.3/C/depth_bound.c
2013-01-20 23:15:09 +00:00

96 lines
2.3 KiB
C

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: it_deep.c *
* Last rev: *
* mods: *
* comments: Support for Iterative Deepening *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif /* SCCS */
#include <math.h>
#ifndef INFINITY
#define INFINITY (1.0/0.0)
#endif
#include "Yap.h"
#ifdef DEPTH_LIMIT
#include "Yatom.h"
STD_PROTO(static Int p_get_depth_limit, ( USES_REGS1 ));
STD_PROTO(static Int p_set_depth_limit, ( USES_REGS1 ));
static Int p_get_depth_limit( USES_REGS1 )
{
Int d = IntOfTerm(DEPTH);
if (d % 2 == 1)
return(Yap_unify(ARG1, MkFloatTerm(INFINITY)));
return(Yap_unify_constant(ARG1, MkIntTerm(d/2)));
}
static Int p_set_depth_limit( USES_REGS1 )
{
Term d = Deref(ARG1);
if (IsVarTerm(d)) {
Yap_Error(INSTANTIATION_ERROR, d, "set-depth_limit");
return(FALSE);
} else if (!IsIntegerTerm(d)) {
if (IsFloatTerm(d) && isinf(FloatOfTerm(d))) {
d = RESET_DEPTH();
} else {
Yap_Error(TYPE_ERROR_INTEGER, d, "set-depth_limit");
return(FALSE);
}
}
d = MkIntTerm(IntegerOfTerm(d)*2);
YENV[E_DEPTH] = d;
DEPTH = d;
return(TRUE);
}
static Int p_set_depth_limit_for_next_call( USES_REGS1 )
{
Term d = Deref(ARG1);
if (IsVarTerm(d)) {
Yap_Error(INSTANTIATION_ERROR, d, "set-depth_limit");
return(FALSE);
} else if (!IsIntegerTerm(d)) {
if (IsFloatTerm(d) && isinf(FloatOfTerm(d))) {
DEPTH = RESET_DEPTH();
return TRUE;
}
Yap_Error(TYPE_ERROR_INTEGER, d, "set-depth_limit");
return(FALSE);
}
d = MkIntTerm(IntegerOfTerm(d)*2);
DEPTH = d;
return(TRUE);
}
void Yap_InitItDeepenPreds(void)
{
Yap_InitCPred("get_depth_limit", 1, p_get_depth_limit, SafePredFlag);
Yap_InitCPred("$set_depth_limit", 1, p_set_depth_limit, 0);
Yap_InitCPred("$set_depth_limit_for_next_call", 1, p_set_depth_limit_for_next_call, 0);
}
#endif