timestamp.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * timestamp.c
 *	  Functions for the built-in SQL92 types "timestamp" and "interval".
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.157.2.1 2005/11/22 18:23:22 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <ctype.h>
#include <math.h>
#include <float.h>
#include <limits.h>
#include <sys/time.h>

#include "access/hash.h"
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "parser/scansup.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/datetime.h"


/*
 * gcc's -ffast-math switch breaks routines that expect exact results from
 * expressions like timeval / SECS_PER_HOUR, where timeval is double.
 */
#ifdef __FAST_MATH__
#error -ffast-math is known to break this code
#endif


/* Set at postmaster start */
TimestampTz PgStartTime;


#ifdef HAVE_INT64_TIMESTAMP
static int64 time2t(const int hour, const int min, const int sec, const fsec_t fsec);
#else
static double time2t(const int hour, const int min, const int sec, const fsec_t fsec);
#endif
static int	EncodeSpecialTimestamp(Timestamp dt, char *str);
static Timestamp dt2local(Timestamp dt, int timezone);
static void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
static void AdjustIntervalForTypmod(Interval *interval, int32 typmod);
static TimestampTz timestamp2timestamptz(Timestamp timestamp);


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

/* timestamp_in()
 * Convert a string to internal form.
 */
Datum
timestamp_in(PG_FUNCTION_ARGS)
{
	char	   *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	Timestamp	result;
	fsec_t		fsec;
	struct pg_tm tt,
			   *tm = &tt;
	int			tz;
	int			dtype;
	int			nf;
	int			dterr;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		workbuf[MAXDATELEN + MAXDATEFIELDS];

	dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
						  field, ftype, MAXDATEFIELDS, &nf);
	if (dterr == 0)
		dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
	if (dterr != 0)
		DateTimeParseError(dterr, str, "timestamp");

	switch (dtype)
	{
		case DTK_DATE:
			if (tm2timestamp(tm, fsec, NULL, &result) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range: \"%s\"", str)));
			break;

		case DTK_EPOCH:
			result = SetEpochTimestamp();
			break;

		case DTK_LATE:
			TIMESTAMP_NOEND(result);
			break;

		case DTK_EARLY:
			TIMESTAMP_NOBEGIN(result);
			break;

		case DTK_INVALID:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			  errmsg("date/time value \"%s\" is no longer supported", str)));

			TIMESTAMP_NOEND(result);
			break;

		default:
			elog(ERROR, "unexpected dtype %d while parsing timestamp \"%s\"",
				 dtype, str);
			TIMESTAMP_NOEND(result);
	}

	AdjustTimestampForTypmod(&result, typmod);

	PG_RETURN_TIMESTAMP(result);
}

/* timestamp_out()
 * Convert a timestamp to external form.
 */
Datum
timestamp_out(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	char	   *result;
	struct pg_tm tt,
			   *tm = &tt;
	fsec_t		fsec;
	char	   *tzn = NULL;
	char		buf[MAXDATELEN + 1];

	if (TIMESTAMP_NOT_FINITE(timestamp))
		EncodeSpecialTimestamp(timestamp, buf);
	else if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) == 0)
		EncodeDateTime(tm, fsec, NULL, &tzn, DateStyle, buf);
	else
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	result = pstrdup(buf);
	PG_RETURN_CSTRING(result);
}

/*
 *		timestamp_recv			- converts external binary format to timestamp
 *
 * We make no attempt to provide compatibility between int and float
 * timestamp representations ...
 */
Datum
timestamp_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	Timestamp	timestamp;
	struct pg_tm tt,
			   *tm = &tt;
	fsec_t		fsec;

#ifdef HAVE_INT64_TIMESTAMP
	timestamp = (Timestamp) pq_getmsgint64(buf);
#else
	timestamp = (Timestamp) pq_getmsgfloat8(buf);
#endif

	/* rangecheck: see if timestamp_out would like it */
	if (TIMESTAMP_NOT_FINITE(timestamp))
		 /* ok */ ;
	else if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) != 0)
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	AdjustTimestampForTypmod(&timestamp, typmod);

	PG_RETURN_TIMESTAMP(timestamp);
}

/*
 *		timestamp_send			- converts timestamp to binary format
 */
Datum
timestamp_send(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	StringInfoData buf;

	pq_begintypsend(&buf);
#ifdef HAVE_INT64_TIMESTAMP
	pq_sendint64(&buf, timestamp);
#else
	pq_sendfloat8(&buf, timestamp);
#endif
	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


/* timestamp_scale()
 * Adjust time type for specified scale factor.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
timestamp_scale(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	int32		typmod = PG_GETARG_INT32(1);
	Timestamp	result;

	result = timestamp;

	AdjustTimestampForTypmod(&result, typmod);

	PG_RETURN_TIMESTAMP(result);
}

static void
AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
{
#ifdef HAVE_INT64_TIMESTAMP
	static const int64 TimestampScales[MAX_TIMESTAMP_PRECISION + 1] = {
		INT64CONST(1000000),
		INT64CONST(100000),
		INT64CONST(10000),
		INT64CONST(1000),
		INT64CONST(100),
		INT64CONST(10),
		INT64CONST(1)
	};

	static const int64 TimestampOffsets[MAX_TIMESTAMP_PRECISION + 1] = {
		INT64CONST(500000),
		INT64CONST(50000),
		INT64CONST(5000),
		INT64CONST(500),
		INT64CONST(50),
		INT64CONST(5),
		INT64CONST(0)
	};
#else
	static const double TimestampScales[MAX_TIMESTAMP_PRECISION + 1] = {
		1,
		10,
		100,
		1000,
		10000,
		100000,
		1000000
	};
#endif

	if (!TIMESTAMP_NOT_FINITE(*time)
		&& (typmod != -1) && (typmod != MAX_TIMESTAMP_PRECISION))
	{
		if (typmod < 0 || typmod > MAX_TIMESTAMP_PRECISION)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				  errmsg("timestamp(%d) precision must be between %d and %d",
						 typmod, 0, MAX_TIMESTAMP_PRECISION)));

		/*
		 * Note: this round-to-nearest code is not completely consistent about
		 * rounding values that are exactly halfway between integral values.
		 * On most platforms, rint() will implement round-to-nearest-even, but
		 * the integer code always rounds up (away from zero).	Is it worth
		 * trying to be consistent?
		 */
#ifdef HAVE_INT64_TIMESTAMP
		if (*time >= INT64CONST(0))
		{
			*time = ((*time + TimestampOffsets[typmod]) / TimestampScales[typmod]) *
				TimestampScales[typmod];
		}
		else
		{
			*time = -((((-*time) + TimestampOffsets[typmod]) / TimestampScales[typmod])
					  * TimestampScales[typmod]);
		}
#else
		*time = rint((double) *time * TimestampScales[typmod]) / TimestampScales[typmod];
#endif
	}
}


/* timestamptz_in()
 * Convert a string to internal form.
 */
Datum
timestamptz_in(PG_FUNCTION_ARGS)
{
	char	   *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	TimestampTz result;
	fsec_t		fsec;
	struct pg_tm tt,
			   *tm = &tt;
	int			tz;
	int			dtype;
	int			nf;
	int			dterr;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		workbuf[MAXDATELEN + MAXDATEFIELDS];

	dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
						  field, ftype, MAXDATEFIELDS, &nf);
	if (dterr == 0)
		dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
	if (dterr != 0)
		DateTimeParseError(dterr, str, "timestamp with time zone");

	switch (dtype)
	{
		case DTK_DATE:
			if (tm2timestamp(tm, fsec, &tz, &result) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range: \"%s\"", str)));
			break;

		case DTK_EPOCH:
			result = SetEpochTimestamp();
			break;

		case DTK_LATE:
			TIMESTAMP_NOEND(result);
			break;

		case DTK_EARLY:
			TIMESTAMP_NOBEGIN(result);
			break;

		case DTK_INVALID:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			  errmsg("date/time value \"%s\" is no longer supported", str)));

			TIMESTAMP_NOEND(result);
			break;

		default:
			elog(ERROR, "unexpected dtype %d while parsing timestamptz \"%s\"",
				 dtype, str);
			TIMESTAMP_NOEND(result);
	}

	AdjustTimestampForTypmod(&result, typmod);

	PG_RETURN_TIMESTAMPTZ(result);
}

/* timestamptz_out()
 * Convert a timestamp to external form.
 */
Datum
timestamptz_out(PG_FUNCTION_ARGS)
{
	TimestampTz dt = PG_GETARG_TIMESTAMPTZ(0);
	char	   *result;
	int			tz;
	struct pg_tm tt,
			   *tm = &tt;
	fsec_t		fsec;
	char	   *tzn;
	char		buf[MAXDATELEN + 1];

	if (TIMESTAMP_NOT_FINITE(dt))
		EncodeSpecialTimestamp(dt, buf);
	else if (timestamp2tm(dt, &tz, tm, &fsec, &tzn, NULL) == 0)
		EncodeDateTime(tm, fsec, &tz, &tzn, DateStyle, buf);
	else
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	result = pstrdup(buf);
	PG_RETURN_CSTRING(result);
}

/*
 *		timestamptz_recv			- converts external binary format to timestamptz
 *
 * We make no attempt to provide compatibility between int and float
 * timestamp representations ...
 */
Datum
timestamptz_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	TimestampTz timestamp;
	int			tz;
	struct pg_tm tt,
			   *tm = &tt;
	fsec_t		fsec;
	char	   *tzn;

#ifdef HAVE_INT64_TIMESTAMP
	timestamp = (TimestampTz) pq_getmsgint64(buf);
#else
	timestamp = (TimestampTz) pq_getmsgfloat8(buf);
#endif

	/* rangecheck: see if timestamptz_out would like it */
	if (TIMESTAMP_NOT_FINITE(timestamp))
		 /* ok */ ;
	else if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn, NULL) != 0)
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	AdjustTimestampForTypmod(&timestamp, typmod);

	PG_RETURN_TIMESTAMPTZ(timestamp);
}

/*
 *		timestamptz_send			- converts timestamptz to binary format
 */
Datum
timestamptz_send(PG_FUNCTION_ARGS)
{
	TimestampTz timestamp = PG_GETARG_TIMESTAMPTZ(0);
	StringInfoData buf;

	pq_begintypsend(&buf);
#ifdef HAVE_INT64_TIMESTAMP
	pq_sendint64(&buf, timestamp);
#else
	pq_sendfloat8(&buf, timestamp);
#endif
	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


/* timestamptz_scale()
 * Adjust time type for specified scale factor.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
timestamptz_scale(PG_FUNCTION_ARGS)
{
	TimestampTz timestamp = PG_GETARG_TIMESTAMPTZ(0);
	int32		typmod = PG_GETARG_INT32(1);
	TimestampTz result;

	result = timestamp;

	AdjustTimestampForTypmod(&result, typmod);

	PG_RETURN_TIMESTAMPTZ(result);
}


/* interval_in()
 * Convert a string to internal form.
 *
 * External format(s):
 *	Uses the generic date/time parsing and decoding routines.
 */
Datum
interval_in(PG_FUNCTION_ARGS)
{
	char	   *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	Interval   *result;
	fsec_t		fsec;
	struct pg_tm tt,
			   *tm = &tt;
	int			dtype;
	int			nf;
	int			dterr;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		workbuf[256];

	tm->tm_year = 0;
	tm->tm_mon = 0;
	tm->tm_mday = 0;
	tm->tm_hour = 0;
	tm->tm_min = 0;
	tm->tm_sec = 0;
	fsec = 0;

	dterr = ParseDateTime(str, workbuf, sizeof(workbuf), field,
						  ftype, MAXDATEFIELDS, &nf);
	if (dterr == 0)
		dterr = DecodeInterval(field, ftype, nf, &dtype, tm, &fsec);
	if (dterr != 0)
	{
		if (dterr == DTERR_FIELD_OVERFLOW)
			dterr = DTERR_INTERVAL_OVERFLOW;
		DateTimeParseError(dterr, str, "interval");
	}

	result = (Interval *) palloc(sizeof(Interval));

	switch (dtype)
	{
		case DTK_DELTA:
			if (tm2interval(tm, fsec, result) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("interval out of range")));
			break;

		case DTK_INVALID:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			  errmsg("date/time value \"%s\" is no longer supported", str)));
			break;

		default:
			elog(ERROR, "unexpected dtype %d while parsing interval \"%s\"",
				 dtype, str);
	}

	AdjustIntervalForTypmod(result, typmod);

	PG_RETURN_INTERVAL_P(result);