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69 lines
1 KiB
C
69 lines
1 KiB
C
/* public domain rewrite of isinf(3) */
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#ifdef __osf__
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#define _IEEE 1
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#include <nan.h>
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int
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isinf(double n)
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{
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if (IsNANorINF(n) && IsINF(n)) {
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return 1;
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}
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else {
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return 0;
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}
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}
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#else
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#include "ruby/3/config.h"
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#if defined(HAVE_FINITE) && defined(HAVE_ISNAN)
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#include <math.h>
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#ifdef HAVE_IEEEFP_H
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#include <ieeefp.h>
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#endif
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/*
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* isinf may be provided only as a macro.
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* ex. HP-UX, Solaris 10
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* http://www.gnu.org/software/automake/manual/autoconf/Function-Portability.html
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*/
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#ifndef isinf
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int
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isinf(double n)
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{
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return (!finite(n) && !isnan(n));
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}
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#endif
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#else
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#ifdef HAVE_STRING_H
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# include <string.h>
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#else
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# include <strings.h>
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#endif
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static double zero(void) { return 0.0; }
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static double one (void) { return 1.0; }
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static double inf (void) { return one() / zero(); }
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int
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isinf(double n)
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{
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static double pinf = 0.0;
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static double ninf = 0.0;
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if (pinf == 0.0) {
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pinf = inf();
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ninf = -pinf;
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}
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return memcmp(&n, &pinf, sizeof n) == 0
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|| memcmp(&n, &ninf, sizeof n) == 0;
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}
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#endif
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#endif
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