float.c

关系型数据库 Postgresql 6.5.2

/*
 *		dtoi4			- converts a float8 number to an int4 number
 */
int32
dtoi4(float64 num)
{
	int32		result;

	if (!PointerIsValid(num))
		elog(ERROR, "dtoi4: unable to convert null", NULL);

	if ((*num < INT_MIN) || (*num > INT_MAX))
		elog(ERROR, "dtoi4: integer out of range", NULL);

	result = rint(*num);
	return result;
}


/*
 *		dtoi2			- converts a float8 number to an int2 number
 */
int16
dtoi2(float64 num)
{
	int16		result;

	if (!PointerIsValid(num))
		elog(ERROR, "dtoi2: unable to convert null", NULL);

	if ((*num < SHRT_MIN) || (*num > SHRT_MAX))
		elog(ERROR, "dtoi2: integer out of range", NULL);

	result = rint(*num);
	return result;
}


/*
 *		i4tod			- converts an int4 number to a float8 number
 */
float64
i4tod(int32 num)
{
	float64		result;

	result = (float64) palloc(sizeof(float64data));

	*result = num;
	return result;
}


/*
 *		i2tod			- converts an int2 number to a float8 number
 */
float64
i2tod(int16 num)
{
	float64		result;

	result = (float64) palloc(sizeof(float64data));

	*result = num;
	return result;
}


/*
 *		ftoi4			- converts a float8 number to an int4 number
 */
int32
ftoi4(float32 num)
{
	int32		result;

	if (!PointerIsValid(num))
		elog(ERROR, "ftoi4: unable to convert null", NULL);

	if ((*num < INT_MIN) || (*num > INT_MAX))
		elog(ERROR, "ftoi4: integer out of range", NULL);

	result = rint(*num);
	return result;
}


/*
 *		ftoi2			- converts a float8 number to an int2 number
 */
int16
ftoi2(float32 num)
{
	int16		result;

	if (!PointerIsValid(num))
		elog(ERROR, "ftoi2: unable to convert null", NULL);

	if ((*num < SHRT_MIN) || (*num > SHRT_MAX))
		elog(ERROR, "ftoi2: integer out of range", NULL);

	result = rint(*num);
	return result;
}


/*
 *		i4tof			- converts an int4 number to a float8 number
 */
float32
i4tof(int32 num)
{
	float32		result;

	result = (float32) palloc(sizeof(float32data));

	*result = num;
	return result;
}


/*
 *		i2tof			- converts an int2 number to a float8 number
 */
float32
i2tof(int16 num)
{
	float32		result;

	result = (float32) palloc(sizeof(float32data));

	*result = num;
	return result;
}


/*
 *		float8_text		- converts a float8 number to a text string
 */
text *
float8_text(float64 num)
{
	text	   *result;
	int			len;
	char	   *str;

	str = float8out(num);
	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

	VARSIZE(result) = len;
	memmove(VARDATA(result), str, (len - VARHDRSZ));

	pfree(str);
	return result;
}	/* float8_text() */


/*
 *		text_float8		- converts a text string to a float8 number
 */
float64
text_float8(text *string)
{
	float64		result;
	int			len;
	char	   *str;

	len = (VARSIZE(string) - VARHDRSZ);
	str = palloc(len + 1);
	memmove(str, VARDATA(string), len);
	*(str + len) = '\0';

	result = float8in(str);
	pfree(str);

	return result;
}	/* text_float8() */


/*
 *		float4_text		- converts a float4 number to a text string
 */
text *
float4_text(float32 num)
{
	text	   *result;
	int			len;
	char	   *str;

	str = float4out(num);
	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

	VARSIZE(result) = len;
	memmove(VARDATA(result), str, (len - VARHDRSZ));

	pfree(str);
	return result;
}	/* float4_text() */


/*
 *		text_float4		- converts a text string to a float4 number
 */
float32
text_float4(text *string)
{
	float32		result;
	int			len;
	char	   *str;

	len = (VARSIZE(string) - VARHDRSZ);
	str = palloc(len + 1);
	memmove(str, VARDATA(string), len);
	*(str + len) = '\0';

	result = float4in(str);
	pfree(str);

	return result;
}	/* text_float4() */


/*
 *		=======================
 *		RANDOM FLOAT8 OPERATORS
 *		=======================
 */

/*
 *		dround			- returns a pointer to	ROUND(arg1)
 */
float64
dround(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
	*result = (float64data) rint(tmp);
	return result;
}


/*
 *		dtrunc			- returns a pointer to	truncation of arg1,
 *						  arg1 >= 0 ... the greatest integer as float8 less
 *										than or equal to arg1
 *						  arg1 < 0	... the greatest integer as float8 greater
 *										than or equal to arg1
 */
float64
dtrunc(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
	if (*arg1 >= 0)
		*result = (float64data) floor(tmp);
	else
		*result = (float64data) -(floor(-tmp));
	return result;
}


/*
 *		dsqrt			- returns a pointer to square root of arg1
 */
float64
dsqrt(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
	*result = (float64data) sqrt(tmp);
	return result;
}


/*
 *		dcbrt			- returns a pointer to cube root of arg1
 */
float64
dcbrt(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
	*result = (float64data) cbrt(tmp);
	return result;
}


/*
 *		dpow			- returns a pointer to pow(arg1,arg2)
 */
float64
dpow(float64 arg1, float64 arg2)
{
	float64		result;
	double		tmp1,
				tmp2;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp1 = *arg1;
	tmp2 = *arg2;
#ifndef finite
	errno = 0;
#endif
	*result = (float64data) pow(tmp1, tmp2);
#ifndef finite
	if (errno != 0)				/* on some machines both EDOM & ERANGE can
								 * occur */
#else
	if (!finite(*result))
#endif
		elog(ERROR, "pow() result is out of range");

	CheckFloat8Val(*result);
	return result;
}


/*
 *		dexp			- returns a pointer to the exponential function of arg1
 */
float64
dexp(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
#ifndef finite
	errno = 0;
#endif
	*result = (float64data) exp(tmp);
#ifndef finite
	if (errno == ERANGE)
#else
	/* infinity implies overflow, zero implies underflow */
	if (!finite(*result) || *result == 0.0)
#endif
		elog(ERROR, "exp() result is out of range");

	CheckFloat8Val(*result);
	return result;
}


/*
 *		dlog1			- returns a pointer to the natural logarithm of arg1
 *						  ("dlog" is already a logging routine...)
 */
float64
dlog1(float64 arg1)
{
	float64		result;
	double		tmp;

	if (!arg1)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	tmp = *arg1;
	if (tmp == 0.0)
		elog(ERROR, "can't take log of zero");
	if (tmp < 0)
		elog(ERROR, "can't take log of a negative number");
	*result = (float64data) log(tmp);

	CheckFloat8Val(*result);
	return result;
}


/*
 *		====================
 *		ARITHMETIC OPERATORS
 *		====================
 */

/*
 *		float48pl		- returns a pointer to arg1 + arg2
 *		float48mi		- returns a pointer to arg1 - arg2
 *		float48mul		- returns a pointer to arg1 * arg2
 *		float48div		- returns a pointer to arg1 / arg2
 */
float64
float48pl(float32 arg1, float64 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 + *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float48mi(float32 arg1, float64 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 - *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float48mul(float32 arg1, float64 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 * *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float48div(float32 arg1, float64 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	if (*arg2 == 0.0)
		elog(ERROR, "float48div: divide by zero");

	*result = *arg1 / *arg2;
	CheckFloat8Val(*result);
	return result;
}

/*
 *		float84pl		- returns a pointer to arg1 + arg2
 *		float84mi		- returns a pointer to arg1 - arg2
 *		float84mul		- returns a pointer to arg1 * arg2
 *		float84div		- returns a pointer to arg1 / arg2
 */
float64
float84pl(float64 arg1, float32 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 + *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float84mi(float64 arg1, float32 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 - *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float84mul(float64 arg1, float32 arg2)
{

	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	*result = *arg1 * *arg2;
	CheckFloat8Val(*result);
	return result;
}

float64
float84div(float64 arg1, float32 arg2)
{
	float64		result;

	if (!arg1 || !arg2)
		return (float64) NULL;

	result = (float64) palloc(sizeof(float64data));

	if (*arg2 == 0.0)
		elog(ERROR, "float48div: divide by zero");

	*result = *arg1 / *arg2;
	CheckFloat8Val(*result);
	return result;
}

/*
 *		====================
 *		COMPARISON OPERATORS
 *		====================
 */

/*
 *		float48{eq,ne,lt,le,gt,ge}		- float4/float8 comparison operations
 */
bool
float48eq(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 == (float) *arg2;
}

bool
float48ne(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 != (float) *arg2;
}

bool
float48lt(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 < (float) *arg2;
}

bool
float48le(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 <= (float) *arg2;
}

bool
float48gt(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 > (float) *arg2;
}

bool
float48ge(float32 arg1, float64 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return *arg1 >= (float) *arg2;
}

/*
 *		float84{eq,ne,lt,le,gt,ge}		- float4/float8 comparison operations
 */
bool
float84eq(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 == *arg2;
}

bool
float84ne(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 != *arg2;
}

bool
float84lt(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 < *arg2;
}

bool
float84le(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 <= *arg2;
}

bool
float84gt(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 > *arg2;
}

bool
float84ge(float64 arg1, float32 arg2)
{
	if (!arg1 || !arg2)
		return 0;

	return (float) *arg1 >= *arg2;
}

/* ========== PRIVATE ROUTINES ========== */

/* From "fdlibm" @ netlib.att.com */

#ifndef HAVE_RINT

/* @(#)s_rint.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

/*
 * rint(x)
 * Return x rounded to integral value according to the prevailing
 * rounding mode.
 * Method:
 *		Using floating addition.
 * Exception:
 *		Inexact flag raised if x not equal to rint(x).
 */

#ifdef __STDC__
static const double
#else
static double
#endif
			one = 1.0,
			TWO52[2] = {
	4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
	-4.50359962737049600000e+15,/* 0xC3300000, 0x00000000 */
};

#ifdef __STDC__
static double
rint(double x)
#else
static double
rint(x)
double		x;

#endif
{
	int			i0,
				n0,
				j0,
				sx;
	unsigned	i,
				i1;
	double		w,
				t;

	n0 = (*((int *) &one) >> 29) ^ 1;
	i0 = *(n0 + (int *) &x);
	sx = (i0 >> 31) & 1;
	i1 = *(1 - n0 + (int *) &x);
	j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
	if (j0 < 20)
	{
		if (j0 < 0)
		{
			if (((i0 & 0x7fffffff) | i1) == 0)
				return x;
			i1 |= (i0 & 0x0fffff);
			i0 &= 0xfffe0000;
			i0 |= ((i1 | -i1) >> 12) & 0x80000;
			*(n0 + (int *) &x) = i0;
			w = TWO52[sx] + x;
			t = w - TWO52[sx];
			i0 = *(n0 + (int *) &t);
			*(n0 + (int *) &t) = (i0 & 0x7fffffff) | (sx << 31);
			return t;
		}
		else
		{
			i = (0x000fffff) >> j0;
			if (((i0 & i) | i1) == 0)
				return x;		/* x is integral */
			i >>= 1;
			if (((i0 & i) | i1) != 0)
			{
				if (j0 == 19)
					i1 = 0x40000000;
				else
					i0 = (i0 & (~i)) | ((0x20000) >> j0);
			}
		}
	}
	else if (j0 > 51)
	{
		if (j0 == 0x400)
			return x + x;		/* inf or NaN */
		else
			return x;			/* x is integral */
	}
	else
	{
		i = ((unsigned) (0xffffffff)) >> (j0 - 20);
		if ((i1 & i) == 0)
			return x;			/* x is integral */
		i >>= 1;
		if ((i1 & i) != 0)
			i1 = (i1 & (~i)) | ((0x40000000) >> (j0 - 20));
	}
	*(n0 + (int *) &x) = i0;
	*(1 - n0 + (int *) &x) = i1;
	w = TWO52[sx] + x;
	return w - TWO52[sx];
}

#endif	 /* !HAVE_RINT */

#ifndef HAVE_CBRT

static
double
cbrt(x)
double		x;
{
	int			isneg = (x < 0.0);
	double		tmpres = pow(fabs(x), (double) 1.0 / (double) 3.0);

	return isneg ? -tmpres : tmpres;
}

#endif	 /* !HAVE_CBRT */