/*-------------------------------------------------------------------------
 *
 * isinf.c
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/port/isinf.c,v 1.6 2004/12/31 22:03:53 pgsql Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "c.h"

#include <float.h>
#include <math.h>

#if HAVE_FPCLASS				/* this is _not_ HAVE_FP_CLASS, and not
								 * typo */

#if HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
int
isinf(double d)
{
	fpclass_t	type = fpclass(d);

	switch (type)
	{
		case FP_NINF:
		case FP_PINF:
			return 1;
		default:
			break;
	}
	return 0;
}

#else

#if defined(HAVE_FP_CLASS) || defined(HAVE_FP_CLASS_D)

#if HAVE_FP_CLASS_H
#include <fp_class.h>
#endif
int
isinf(x)
double		x;
{
#if HAVE_FP_CLASS
	int			fpclass = fp_class(x);

#else
	int			fpclass = fp_class_d(x);
#endif

	if (fpclass == FP_POS_INF)
		return 1;
	if (fpclass == FP_NEG_INF)
		return -1;
	return 0;
}

#elif defined(HAVE_CLASS)
int
isinf(double x)
{
	int			fpclass = class(x);

	if (fpclass == FP_PLUS_INF)
		return 1;
	if (fpclass == FP_MINUS_INF)
		return -1;
	return 0;
}
#endif
#endif

#ifdef __QNX__
#include <float.h>

int
isinf(double x)
{
	if (x == HUGE_VAL)
		return 1;
	if (x == -HUGE_VAL)
		return -1;
	return 0;
}

#endif
