path: root/src/backend/utils/adt/float.c

/*-------------------------------------------------------------------------
 *
 * float.c
 *	  Functions for the built-in floating-point types.
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/float.c,v 1.76 2001/10/28 06:25:52 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
/*----------
 * OLD COMMENTS
 *		Basic float4 ops:
 *		 float4in, float4out, float4abs, float4um, float4up
 *		Basic float8 ops:
 *		 float8in, float8out, float8abs, float8um, float8up
 *		Arithmetic operators:
 *		 float4pl, float4mi, float4mul, float4div
 *		 float8pl, float8mi, float8mul, float8div
 *		Comparison operators:
 *		 float4eq, float4ne, float4lt, float4le, float4gt, float4ge, float4cmp
 *		 float8eq, float8ne, float8lt, float8le, float8gt, float8ge, float8cmp
 *		Conversion routines:
 *		 ftod, dtof, i4tod, dtoi4, i2tod, dtoi2, itof, ftoi, i2tof, ftoi2
 *
 *		Random float8 ops:
 *		 dround, dtrunc, dsqrt, dcbrt, dpow, dexp, dlog1
 *		Arithmetic operators:
 *		 float48pl, float48mi, float48mul, float48div
 *		 float84pl, float84mi, float84mul, float84div
 *		Comparison operators:
 *		 float48eq, float48ne, float48lt, float48le, float48gt, float48ge
 *		 float84eq, float84ne, float84lt, float84le, float84gt, float84ge
 *
 *		(You can do the arithmetic and comparison stuff using conversion
 *		 routines, but then you pay the overhead of invoking a separate
 *		 conversion function...)
 *
 * XXX GLUESOME STUFF. FIX IT! -AY '94
 *
 *		Added some additional conversion routines and cleaned up
 *		 a bit of the existing code. Need to change the error checking
 *		 for calls to pow(), exp() since on some machines (my Linux box
 *		 included) these routines do not set errno. - tgl 97/05/10
 *----------
 */
#include "postgres.h"

#include <ctype.h>
#include <errno.h>
#include <float.h>				/* faked on sunos4 */
#include <math.h>

#include <limits.h>
/* for finite() on Solaris */
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

#include "fmgr.h"
#include "utils/array.h"
#include "utils/builtins.h"


#if !(NeXT && NX_CURRENT_COMPILER_RELEASE > NX_COMPILER_RELEASE_3_2)
 /* NS3.3 has conflicting declarations of these in <math.h> */

#ifndef atof
extern double atof(const char *p);
#endif

#ifndef HAVE_CBRT
#define cbrt my_cbrt
static double cbrt(double x);

#else
#if !defined(nextstep)
extern double cbrt(double x);
#endif
#endif	 /* HAVE_CBRT */

#ifndef HAVE_RINT
#define rint my_rint
static double rint(double x);

#else
extern double rint(double x);
#endif	 /* HAVE_RINT */
#endif	 /* NeXT check */


static void CheckFloat4Val(double val);
static void CheckFloat8Val(double val);

#ifndef M_PI
/* from my RH5.2 gcc math.h file - thomas 2000-04-03 */
#define M_PI 3.14159265358979323846
#endif

#ifndef NAN
#define NAN		(0.0/0.0)
#endif

#ifndef SHRT_MAX
#define SHRT_MAX 32767
#endif
#ifndef SHRT_MIN
#define SHRT_MIN (-32768)
#endif

#define FORMAT			'g'		/* use "g" output format as standard
								 * format */
/* not sure what the following should be, but better to make it over-sufficient */
#define MAXFLOATWIDTH	64
#define MAXDOUBLEWIDTH	128

/* ========== USER I/O ROUTINES ========== */


#define FLOAT4_MAX		 FLT_MAX
#define FLOAT4_MIN		 FLT_MIN
#define FLOAT8_MAX		 DBL_MAX
#define FLOAT8_MIN		 DBL_MIN


/*
   check to see if a float4 val is outside of
   the FLOAT4_MIN, FLOAT4_MAX bounds.

   raise an elog warning if it is
*/
static void
CheckFloat4Val(double val)
{
	/*
	 * defining unsafe floats's will make float4 and float8 ops faster at
	 * the cost of safety, of course!
	 */
#ifdef UNSAFE_FLOATS
	return;
#else
	if (fabs(val) > FLOAT4_MAX)
		elog(ERROR, "Bad float4 input format -- overflow");
	if (val != 0.0 && fabs(val) < FLOAT4_MIN)
		elog(ERROR, "Bad float4 input format -- underflow");
	return;
#endif	 /* UNSAFE_FLOATS */
}

/*
   check to see if a float8 val is outside of
   the FLOAT8_MIN, FLOAT8_MAX bounds.

   raise an elog warning if it is
*/
static void
CheckFloat8Val(double val)
{
	/*
	 * defining unsafe floats's will make float4 and float8 ops faster at
	 * the cost of safety, of course!
	 */
#ifdef UNSAFE_FLOATS
	return;
#else
	if (fabs(val) > FLOAT8_MAX)
		elog(ERROR, "Bad float8 input format -- overflow");
	if (val != 0.0 && fabs(val) < FLOAT8_MIN)
		elog(ERROR, "Bad float8 input format -- underflow");
	return;
#endif	 /* UNSAFE_FLOATS */
}

/*
 *		float4in		- converts "num" to float
 *						  restricted syntax:
 *						  {<sp>} [+|-] {digit} [.{digit}] [<exp>]
 *						  where <sp> is a space, digit is 0-9,
 *						  <exp> is "e" or "E" followed by an integer.
 */
Datum
float4in(PG_FUNCTION_ARGS)
{
	char	   *num = PG_GETARG_CSTRING(0);
	double		val;
	char	   *endptr;

	errno = 0;
	val = strtod(num, &endptr);
	if (*endptr != '\0')
	{
		/*
		 * XXX we should accept "Infinity" and "-Infinity" too, but what
		 * are the correct values to assign?  HUGE_VAL will provoke an
		 * error from CheckFloat4Val.
		 */
		if (strcasecmp(num, "NaN") == 0)
			val = NAN;
		else
			elog(ERROR, "Bad float4 input format '%s'", num);
	}
	else
	{
		if (errno == ERANGE)
			elog(ERROR, "Input '%s' is out of range for float4", num);
	}

	/*
	 * if we get here, we have a legal double, still need to check to see
	 * if it's a legal float
	 */
	CheckFloat4Val(val);

	PG_RETURN_FLOAT4((float4) val);
}

/*
 *		float4out		- converts a float4 number to a string
 *						  using a standard output format
 */
Datum
float4out(PG_FUNCTION_ARGS)
{
	float4		num = PG_GETARG_FLOAT4(0);
	char	   *ascii = (char *) palloc(MAXFLOATWIDTH + 1);
	int			infflag;

	if (isnan(num))
		PG_RETURN_CSTRING(strcpy(ascii, "NaN"));
	infflag = isinf(num);
	if (infflag > 0)
		PG_RETURN_CSTRING(strcpy(ascii, "Infinity"));
	if (infflag < 0)
		PG_RETURN_CSTRING(strcpy(ascii, "-Infinity"));

	sprintf(ascii, "%.*g", FLT_DIG, num);
	PG_RETURN_CSTRING(ascii);
}

/*
 *		float8in		- converts "num" to float8
 *						  restricted syntax:
 *						  {<sp>} [+|-] {digit} [.{digit}] [<exp>]
 *						  where <sp> is a space, digit is 0-9,
 *						  <exp> is "e" or "E" followed by an integer.
 */
Datum
float8in(PG_FUNCTION_ARGS)
{
	char	   *