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