float.c

postgresql8.3.4源码,开源数据库

	errno = 0;
	result = exp(arg1);
	if (errno == ERANGE && result != 0 && !isinf(result))
		result = get_float8_infinity();

	CHECKFLOATVAL(result, isinf(arg1), false);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dlog1			- returns the natural logarithm of arg1
 */
Datum
dlog1(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	/*
	 * Emit particular SQLSTATE error codes for ln(). This is required by the
	 * SQL standard.
	 */
	if (arg1 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_LOG),
				 errmsg("cannot take logarithm of zero")));
	if (arg1 < 0)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_LOG),
				 errmsg("cannot take logarithm of a negative number")));

	result = log(arg1);

	CHECKFLOATVAL(result, isinf(arg1), arg1 == 1);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dlog10			- returns the base 10 logarithm of arg1
 */
Datum
dlog10(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	/*
	 * Emit particular SQLSTATE error codes for log(). The SQL spec doesn't
	 * define log(), but it does define ln(), so it makes sense to emit the
	 * same error code for an analogous error condition.
	 */
	if (arg1 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_LOG),
				 errmsg("cannot take logarithm of zero")));
	if (arg1 < 0)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_LOG),
				 errmsg("cannot take logarithm of a negative number")));

	result = log10(arg1);

	CHECKFLOATVAL(result, isinf(arg1), arg1 == 1);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dacos			- returns the arccos of arg1 (radians)
 */
Datum
dacos(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	/*
	 * We use errno here because the trigonometric functions are cyclic and
	 * hard to check for underflow.
	 */
	errno = 0;
	result = acos(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		dasin			- returns the arcsin of arg1 (radians)
 */
Datum
dasin(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = asin(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		datan			- returns the arctan of arg1 (radians)
 */
Datum
datan(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = atan(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		atan2			- returns the arctan2 of arg1 (radians)
 */
Datum
datan2(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	errno = 0;
	result = atan2(arg1, arg2);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		dcos			- returns the cosine of arg1 (radians)
 */
Datum
dcos(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = cos(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		dcot			- returns the cotangent of arg1 (radians)
 */
Datum
dcot(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = tan(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	result = 1.0 / result;
	CHECKFLOATVAL(result, true /* cotan(pi/2) == inf */ , true);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dsin			- returns the sine of arg1 (radians)
 */
Datum
dsin(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = sin(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

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


/*
 *		dtan			- returns the tangent of arg1 (radians)
 */
Datum
dtan(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = tan(arg1);
	if (errno != 0)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CHECKFLOATVAL(result, true /* tan(pi/2) == Inf */ , true);
	PG_RETURN_FLOAT8(result);
}


/*
 *		degrees		- returns degrees converted from radians
 */
Datum
degrees(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	result = arg1 * (180.0 / M_PI);

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


/*
 *		dpi				- returns the constant PI
 */
Datum
dpi(PG_FUNCTION_ARGS)
{
	PG_RETURN_FLOAT8(M_PI);
}


/*
 *		radians		- returns radians converted from degrees
 */
Datum
radians(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	result = arg1 * (M_PI / 180.0);

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


/*
 *		drandom		- returns a random number
 */
Datum
drandom(PG_FUNCTION_ARGS)
{
	float8		result;

	/* result [0.0 - 1.0) */
	result = (double) random() / ((double) MAX_RANDOM_VALUE + 1);

	PG_RETURN_FLOAT8(result);
}


/*
 *		setseed		- set seed for the random number generator
 */
Datum
setseed(PG_FUNCTION_ARGS)
{
	float8		seed = PG_GETARG_FLOAT8(0);
	int			iseed = (int) (seed * MAX_RANDOM_VALUE);

	srandom((unsigned int) iseed);

	PG_RETURN_VOID();
}



/*
 *		=========================
 *		FLOAT AGGREGATE OPERATORS
 *		=========================
 *
 *		float8_accum		- accumulate for AVG(), variance aggregates, etc.
 *		float4_accum		- same, but input data is float4
 *		float8_avg			- produce final result for float AVG()
 *		float8_var_samp		- produce final result for float VAR_SAMP()
 *		float8_var_pop		- produce final result for float VAR_POP()
 *		float8_stddev_samp	- produce final result for float STDDEV_SAMP()
 *		float8_stddev_pop	- produce final result for float STDDEV_POP()
 *
 * The transition datatype for all these aggregates is a 3-element array
 * of float8, holding the values N, sum(X), sum(X*X) in that order.
 *
 * Note that we represent N as a float to avoid having to build a special
 * datatype.  Given a reasonable floating-point implementation, there should
 * be no accuracy loss unless N exceeds 2 ^ 52 or so (by which time the
 * user will have doubtless lost interest anyway...)
 */

static float8 *
check_float8_array(ArrayType *transarray, const char *caller, int n)
{
	/*
	 * We expect the input to be an N-element float array; verify that. We
	 * don't need to use deconstruct_array() since the array data is just
	 * going to look like a C array of N float8 values.
	 */
	if (ARR_NDIM(transarray) != 1 ||
		ARR_DIMS(transarray)[0] != n ||
		ARR_HASNULL(transarray) ||
		ARR_ELEMTYPE(transarray) != FLOAT8OID)
		elog(ERROR, "%s: expected %d-element float8 array", caller, n);
	return (float8 *) ARR_DATA_PTR(transarray);
}

Datum
float8_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8		newval = PG_GETARG_FLOAT8(1);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2;

	transvalues = check_float8_array(transarray, "float8_accum", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	N += 1.0;
	sumX += newval;
	CHECKFLOATVAL(sumX, isinf(transvalues[1]) || isinf(newval), true);
	sumX2 += newval * newval;
	CHECKFLOATVAL(sumX2, isinf(transvalues[2]) || isinf(newval), true);

	/*
	 * If we're invoked by nodeAgg, we can cheat and modify our first
	 * parameter in-place to reduce palloc overhead. Otherwise we construct a
	 * new array with the updated transition data and return it.
	 */
	if (fcinfo->context && IsA(fcinfo->context, AggState))
	{
		transvalues[0] = N;
		transvalues[1] = sumX;
		transvalues[2] = sumX2;

		PG_RETURN_ARRAYTYPE_P(transarray);
	}
	else
	{
		Datum		transdatums[3];
		ArrayType  *result;

		transdatums[0] = Float8GetDatumFast(N);
		transdatums[1] = Float8GetDatumFast(sumX);
		transdatums[2] = Float8GetDatumFast(sumX2);

		result = construct_array(transdatums, 3,
								 FLOAT8OID,
							 sizeof(float8), false /* float8 byval */ , 'd');

		PG_RETURN_ARRAYTYPE_P(result);
	}
}

Datum
float4_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);

	/* do computations as float8 */
	float8		newval = PG_GETARG_FLOAT4(1);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2;

	transvalues = check_float8_array(transarray, "float4_accum", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	N += 1.0;
	sumX += newval;
	CHECKFLOATVAL(sumX, isinf(transvalues[1]) || isinf(newval), true);
	sumX2 += newval * newval;
	CHECKFLOATVAL(sumX2, isinf(transvalues[2]) || isinf(newval), true);

	/*
	 * If we're invoked by nodeAgg, we can cheat and modify our first
	 * parameter in-place to reduce palloc overhead. Otherwise we construct a
	 * new array with the updated transition data and return it.
	 */
	if (fcinfo->context && IsA(fcinfo->context, AggState))
	{
		transvalues[0] = N;
		transvalues[1] = sumX;
		transvalues[2] = sumX2;

		PG_RETURN_ARRAYTYPE_P(transarray);
	}
	else
	{
		Datum		transdatums[3];
		ArrayType  *result;

		transdatums[0] = Float8GetDatumFast(N);
		transdatums[1] = Float8GetDatumFast(sumX);
		transdatums[2] = Float8GetDatumFast(sumX2);

		result = construct_array(transdatums, 3,
								 FLOAT8OID,
							 sizeof(float8), false /* float8 byval */ , 'd');

		PG_RETURN_ARRAYTYPE_P(result);
	}
}

Datum
float8_avg(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX;

	transvalues = check_float8_array(transarray, "float8_avg", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	/* ignore sumX2 */

	/* SQL92 defines AVG of no values to be NULL */
	if (N == 0.0)
		PG_RETURN_NULL();

	PG_RETURN_FLOAT8(sumX / N);
}

Datum
float8_var_pop(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_var_pop", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Population variance is undefined when N is 0, so return NULL */
	if (N == 0.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;
	CHECKFLOATVAL(numerator, isinf(sumX2) || isinf(sumX), true);

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(numerator / (N * N));
}

Datum
float8_var_samp(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_var_samp", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Sample variance is undefined when N is 0 or 1, so return NULL */
	if (N <= 1.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;
	CHECKFLOATVAL(numerator, isinf(sumX2) || isinf(sumX), true);

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(numerator / (N * (N - 1.0)));
}

Datum
float8_stddev_pop(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_stddev_pop", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Population stddev is undefined when N is 0, so return NULL */
	if (N == 0.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;
	CHECKFLOATVAL(numerator, isinf(sumX2) || isinf(sumX), true);

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(sqrt(numerator / (N * N)));
}

Datum
float8_stddev_samp(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_stddev_samp", 3);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Sample stddev is undefined when N is 0 or 1, so return NULL */
	if (N <= 1.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;
	CHECKFLOATVAL(numerator, isinf(sumX2) || isinf(sumX), true);

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(sqrt(numerator / (N * (N - 1.0))));
}

/*
 *		=========================
 *		SQL2003 BINARY AGGREGATES
 *		=========================
 *
 * The transition datatype for all these aggregates is a 6-element array of
 * float8, holding the values N, sum(X), sum(X*X), sum(Y), sum(Y*Y), sum(X*Y)
 * in that order.  Note that Y is the first argument to the aggregates!
 *
 * It might seem attractive to optimize this by having multiple accumulator
 * functions that only calculate the sums actually needed.	But on most
 * modern machines, a couple of extra floating-point multiplies will be
 * insignificant compared to the other per-tuple overhead, so I've chosen
 * to minimize code space instead.
 */

Datum
float8_regr_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8		newvalY = PG_GETARG_FLOAT8(1);
	float8		newvalX = PG_GETARG_FLOAT8(2);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				sumY,
				sumY2,
				sumXY;

	transvalues = check_float8_array(transarray, "float8_regr_accum", 6);
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];
	sumY = transvalues[3];
	sumY2 = transvalues[4];
	sumXY = transvalues[5];

	N += 1.0;
	sumX += newvalX;
	CHECKFLOATVAL(sumX, isinf(transvalues[1]) || isinf(newvalX), true);
	sumX2 += newvalX * newvalX;
	CHECKFLOATVAL(sumX2, isinf(transvalues[2]) || isinf(newvalX), true);
	sumY += newvalY;
	CHECKFLOATVAL(sumY, isinf(transvalues[3]) || isinf(newvalY), true);
	sumY2 += newvalY * newvalY;
	CHECKFLOATVAL(sumY2, isinf(transvalues[4]) || isinf(newvalY), true);
	sumXY += newvalX * newvalY;
	CHECKFLOATVAL(sumXY, isinf(transvalues[5]) || isinf(newvalX) ||
				  isinf(newvalY), true);

	/*
	 * If we're invoked by nodeAgg, we can cheat and modify our first
	 * parameter in-place to reduce palloc overhead. Otherwise we construct a
	 * new array with the updated transition data and return it.
	 */
	if (fcinfo->context && IsA(fcinfo->context, AggState))
	{
		transvalues[0] = N;
		transvalues[1] = sumX;
		transvalues[2] = sumX2;
		transvalues[3] = sumY;
		transvalues[4] = sumY2;
		transvalues[5] = sumXY;

		PG_RETURN_ARRAYTYPE_P(transarray);
	}
	else
	{
		Datum		transdatums[6];
		ArrayType  *result;

		transdatums[0] = Float8GetDatumFast(N);
		transdatums[1] = Float8GetDatumFast(sumX);
		transdatums[2] = Float8GetDatumFast(sumX2);
		transdatums[3] = Float8GetDatumFast(sumY);
		transdatums[4] = Float8GetDatumFast(sumY2);
		transdatums[5] = Float8GetDatumFast(sumXY);

		result = construct_array(transdatums, 6,
								 FLOAT8OID,
								 sizeof(float8),
								 false /* float8 byval */ , 'd');

		PG_RETURN_ARRAYTYPE_P(result);
	}
}

Datum
float8_regr_sxx(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,