float.c

postgresql8.3.4源码,开源数据库

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

/*
 *		float4pl		- returns arg1 + arg2
 *		float4mi		- returns arg1 - arg2
 *		float4mul		- returns arg1 * arg2
 *		float4div		- returns arg1 / arg2
 */
Datum
float4pl(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT4(1);
	float4		result;

	result = arg1 + arg2;

	/*
	 * There isn't any way to check for underflow of addition/subtraction
	 * because numbers near the underflow value have been already been to the
	 * point where we can't detect the that the two values were originally
	 * different, e.g. on x86, '1e-45'::float4 == '2e-45'::float4 ==
	 * 1.4013e-45.
	 */
	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), true);
	PG_RETURN_FLOAT4(result);
}

Datum
float4mi(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float4		result;

	result = arg1 - arg2;
	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), true);
	PG_RETURN_FLOAT4(result);
}

Datum
float4mul(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float4		result;

	result = arg1 * arg2;
	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2),
				  arg1 == 0 || arg2 == 0);
	PG_RETURN_FLOAT4(result);
}

Datum
float4div(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float4		result;

	if (arg2 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_DIVISION_BY_ZERO),
				 errmsg("division by zero")));

	/* Do division in float8, then check for overflow */
	result = arg1 / arg2;

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), arg1 == 0);
	PG_RETURN_FLOAT4(result);
}

/*
 *		float8pl		- returns arg1 + arg2
 *		float8mi		- returns arg1 - arg2
 *		float8mul		- returns arg1 * arg2
 *		float8div		- returns arg1 / arg2
 */
Datum
float8pl(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 + arg2;

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), true);
	PG_RETURN_FLOAT8(result);
}

Datum
float8mi(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 - arg2;

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), true);
	PG_RETURN_FLOAT8(result);
}

Datum
float8mul(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 * arg2;

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2),
				  arg1 == 0 || arg2 == 0);
	PG_RETURN_FLOAT8(result);
}

Datum
float8div(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	if (arg2 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_DIVISION_BY_ZERO),
				 errmsg("division by zero")));

	result = arg1 / arg2;

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), arg1 == 0);
	PG_RETURN_FLOAT8(result);
}


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

/*
 *		float4{eq,ne,lt,le,gt,ge}		- float4/float4 comparison operations
 */
static int
float4_cmp_internal(float4 a, float4 b)
{
	/*
	 * We consider all NANs to be equal and larger than any non-NAN. This is
	 * somewhat arbitrary; the important thing is to have a consistent sort
	 * order.
	 */
	if (isnan(a))
	{
		if (isnan(b))
			return 0;			/* NAN = NAN */
		else
			return 1;			/* NAN > non-NAN */
	}
	else if (isnan(b))
	{
		return -1;				/* non-NAN < NAN */
	}
	else
	{
		if (a > b)
			return 1;
		else if (a < b)
			return -1;
		else
			return 0;
	}
}

Datum
float4eq(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) == 0);
}

Datum
float4ne(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) != 0);
}

Datum
float4lt(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) < 0);
}

Datum
float4le(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) <= 0);
}

Datum
float4gt(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) > 0);
}

Datum
float4ge(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float4_cmp_internal(arg1, arg2) >= 0);
}

Datum
btfloat4cmp(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_INT32(float4_cmp_internal(arg1, arg2));
}

/*
 *		float8{eq,ne,lt,le,gt,ge}		- float8/float8 comparison operations
 */
static int
float8_cmp_internal(float8 a, float8 b)
{
	/*
	 * We consider all NANs to be equal and larger than any non-NAN. This is
	 * somewhat arbitrary; the important thing is to have a consistent sort
	 * order.
	 */
	if (isnan(a))
	{
		if (isnan(b))
			return 0;			/* NAN = NAN */
		else
			return 1;			/* NAN > non-NAN */
	}
	else if (isnan(b))
	{
		return -1;				/* non-NAN < NAN */
	}
	else
	{
		if (a > b)
			return 1;
		else if (a < b)
			return -1;
		else
			return 0;
	}
}

Datum
float8eq(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) == 0);
}

Datum
float8ne(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) != 0);
}

Datum
float8lt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) < 0);
}

Datum
float8le(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) <= 0);
}

Datum
float8gt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) > 0);
}

Datum
float8ge(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) >= 0);
}

Datum
btfloat8cmp(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_INT32(float8_cmp_internal(arg1, arg2));
}

Datum
btfloat48cmp(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	/* widen float4 to float8 and then compare */
	PG_RETURN_INT32(float8_cmp_internal(arg1, arg2));
}

Datum
btfloat84cmp(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	/* widen float4 to float8 and then compare */
	PG_RETURN_INT32(float8_cmp_internal(arg1, arg2));
}


/*
 *		===================
 *		CONVERSION ROUTINES
 *		===================
 */

/*
 *		ftod			- converts a float4 number to a float8 number
 */
Datum
ftod(PG_FUNCTION_ARGS)
{
	float4		num = PG_GETARG_FLOAT4(0);

	PG_RETURN_FLOAT8((float8) num);
}


/*
 *		dtof			- converts a float8 number to a float4 number
 */
Datum
dtof(PG_FUNCTION_ARGS)
{
	float8		num = PG_GETARG_FLOAT8(0);

	CHECKFLOATVAL((float4) num, isinf(num), num == 0);

	PG_RETURN_FLOAT4((float4) num);
}


/*
 *		dtoi4			- converts a float8 number to an int4 number
 */
Datum
dtoi4(PG_FUNCTION_ARGS)
{
	float8		num = PG_GETARG_FLOAT8(0);
	int32		result;

	/* 'Inf' is handled by INT_MAX */
	if (num < INT_MIN || num > INT_MAX || isnan(num))
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("integer out of range")));

	result = (int32) rint(num);
	PG_RETURN_INT32(result);
}


/*
 *		dtoi2			- converts a float8 number to an int2 number
 */
Datum
dtoi2(PG_FUNCTION_ARGS)
{
	float8		num = PG_GETARG_FLOAT8(0);

	if (num < SHRT_MIN || num > SHRT_MAX || isnan(num))
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("smallint out of range")));

	PG_RETURN_INT16((int16) rint(num));
}


/*
 *		i4tod			- converts an int4 number to a float8 number
 */
Datum
i4tod(PG_FUNCTION_ARGS)
{
	int32		num = PG_GETARG_INT32(0);

	PG_RETURN_FLOAT8((float8) num);
}


/*
 *		i2tod			- converts an int2 number to a float8 number
 */
Datum
i2tod(PG_FUNCTION_ARGS)
{
	int16		num = PG_GETARG_INT16(0);

	PG_RETURN_FLOAT8((float8) num);
}


/*
 *		ftoi4			- converts a float4 number to an int4 number
 */
Datum
ftoi4(PG_FUNCTION_ARGS)
{
	float4		num = PG_GETARG_FLOAT4(0);

	if (num < INT_MIN || num > INT_MAX || isnan(num))
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("integer out of range")));

	PG_RETURN_INT32((int32) rint(num));
}


/*
 *		ftoi2			- converts a float4 number to an int2 number
 */
Datum
ftoi2(PG_FUNCTION_ARGS)
{
	float4		num = PG_GETARG_FLOAT4(0);

	if (num < SHRT_MIN || num > SHRT_MAX || isnan(num))
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("smallint out of range")));

	PG_RETURN_INT16((int16) rint(num));
}


/*
 *		i4tof			- converts an int4 number to a float4 number
 */
Datum
i4tof(PG_FUNCTION_ARGS)
{
	int32		num = PG_GETARG_INT32(0);

	PG_RETURN_FLOAT4((float4) num);
}


/*
 *		i2tof			- converts an int2 number to a float4 number
 */
Datum
i2tof(PG_FUNCTION_ARGS)
{
	int16		num = PG_GETARG_INT16(0);

	PG_RETURN_FLOAT4((float4) num);
}


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

/*
 *		dround			- returns	ROUND(arg1)
 */
Datum
dround(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);

	PG_RETURN_FLOAT8(rint(arg1));
}

/*
 *		dceil			- returns the smallest integer greater than or
 *						  equal to the specified float
 */
Datum
dceil(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);

	PG_RETURN_FLOAT8(ceil(arg1));
}

/*
 *		dfloor			- returns the largest integer lesser than or
 *						  equal to the specified float
 */
Datum
dfloor(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);

	PG_RETURN_FLOAT8(floor(arg1));
}

/*
 *		dsign			- returns -1 if the argument is less than 0, 0
 *						  if the argument is equal to 0, and 1 if the
 *						  argument is greater than zero.
 */
Datum
dsign(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	if (arg1 > 0)
		result = 1.0;
	else if (arg1 < 0)
		result = -1.0;
	else
		result = 0.0;

	PG_RETURN_FLOAT8(result);
}

/*
 *		dtrunc			- returns truncation-towards-zero of arg1,
 *						  arg1 >= 0 ... the greatest integer less
 *										than or equal to arg1
 *						  arg1 < 0	... the least integer greater
 *										than or equal to arg1
 */
Datum
dtrunc(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	if (arg1 >= 0)
		result = floor(arg1);
	else
		result = -floor(-arg1);

	PG_RETURN_FLOAT8(result);
}


/*
 *		dsqrt			- returns square root of arg1
 */
Datum
dsqrt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	if (arg1 < 0)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_POWER_FUNCTION),
				 errmsg("cannot take square root of a negative number")));

	result = sqrt(arg1);

	CHECKFLOATVAL(result, isinf(arg1), arg1 == 0);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dcbrt			- returns cube root of arg1
 */
Datum
dcbrt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	result = cbrt(arg1);
	CHECKFLOATVAL(result, isinf(arg1), arg1 == 0);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dpow			- returns pow(arg1,arg2)
 */
Datum
dpow(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	/*
	 * The SQL spec requires that we emit a particular SQLSTATE error code for
	 * certain error conditions.
	 */
	if ((arg1 == 0 && arg2 < 0) ||
		(arg1 < 0 && floor(arg2) != arg2))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_POWER_FUNCTION),
				 errmsg("invalid argument for power function")));

	/*
	 * pow() sets errno only on some platforms, depending on whether it
	 * follows _IEEE_, _POSIX_, _XOPEN_, or _SVID_, so we try to avoid using
	 * errno.  However, some platform/CPU combinations return errno == EDOM
	 * and result == Nan for negative arg1 and very large arg2 (they must be
	 * using something different from our floor() test to decide it's
	 * invalid).  Other platforms (HPPA) return errno == ERANGE and a large
	 * (HUGE_VAL) but finite result to signal overflow.
	 */
	errno = 0;
	result = pow(arg1, arg2);
	if (errno == EDOM && isnan(result))
	{
		if ((fabs(arg1) > 1 && arg2 >= 0) || (fabs(arg1) < 1 && arg2 < 0))
			/* The sign of Inf is not significant in this case. */
			result = get_float8_infinity();
		else if (fabs(arg1) != 1)
			result = 0;
		else
			result = 1;
	}
	else if (errno == ERANGE && result != 0 && !isinf(result))
		result = get_float8_infinity();

	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), arg1 == 0);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dexp			- returns the exponential function of arg1
 */
Datum
dexp(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;