date.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,274 行 · 第 1/4 页

/*-------------------------------------------------------------------------
 *
 * date.c
 *	  implements DATE and TIME data types specified in SQL-92 standard
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994-5, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/date.c,v 1.93.2.1 2004/06/13 17:17:48 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <ctype.h>
#include <limits.h>
#include <time.h>
#include <float.h>

#include "access/hash.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/nabstime.h"
#include "utils/timestamp.h"

/*
 * gcc's -ffast-math switch breaks routines that expect exact results from
 * expressions like timeval / 3600, where timeval is double.
 */
#ifdef __FAST_MATH__
#error -ffast-math is known to break this code
#endif


static int	time2tm(TimeADT time, struct tm * tm, fsec_t *fsec);
static int	timetz2tm(TimeTzADT *time, struct tm * tm, fsec_t *fsec, int *tzp);
static int	tm2time(struct tm * tm, fsec_t fsec, TimeADT *result);
static int	tm2timetz(struct tm * tm, fsec_t fsec, int tz, TimeTzADT *result);
static void AdjustTimeForTypmod(TimeADT *time, int32 typmod);

/*****************************************************************************
 *	 Date ADT
 *****************************************************************************/


/* date_in()
 * Given date text string, convert to internal date format.
 */
Datum
date_in(PG_FUNCTION_ARGS)
{
	char	   *str = PG_GETARG_CSTRING(0);
	DateADT		date;
	fsec_t		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			tzp;
	int			dtype;
	int			nf;
	int			dterr;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		lowstr[MAXDATELEN + 1];

	if (strlen(str) >= sizeof(lowstr))
		dterr = DTERR_BAD_FORMAT;
	else
		dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
	if (dterr == 0)
		dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tzp);
	if (dterr != 0)
		DateTimeParseError(dterr, str, "date");

	switch (dtype)
	{
		case DTK_DATE:
			break;

		case DTK_CURRENT:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("date/time value \"current\" is no longer supported")));

			GetCurrentDateTime(tm);
			break;

		case DTK_EPOCH:
			GetEpochTime(tm);
			break;

		default:
			DateTimeParseError(DTERR_BAD_FORMAT, str, "date");
			break;
	}

	date = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;

	PG_RETURN_DATEADT(date);
}

/* date_out()
 * Given internal format date, convert to text string.
 */
Datum
date_out(PG_FUNCTION_ARGS)
{
	DateADT		date = PG_GETARG_DATEADT(0);
	char	   *result;
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];

	j2date(date + POSTGRES_EPOCH_JDATE,
		   &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));

	EncodeDateOnly(tm, DateStyle, buf);

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

/*
 *		date_recv			- converts external binary format to date
 */
Datum
date_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);

	PG_RETURN_DATEADT((DateADT) pq_getmsgint(buf, sizeof(DateADT)));
}

/*
 *		date_send			- converts date to binary format
 */
Datum
date_send(PG_FUNCTION_ARGS)
{
	DateADT		date = PG_GETARG_DATEADT(0);
	StringInfoData buf;

	pq_begintypsend(&buf);
	pq_sendint(&buf, date, sizeof(date));
	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


Datum
date_eq(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 == dateVal2);
}

Datum
date_ne(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 != dateVal2);
}

Datum
date_lt(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 < dateVal2);
}

Datum
date_le(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 <= dateVal2);
}

Datum
date_gt(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 > dateVal2);
}

Datum
date_ge(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_BOOL(dateVal1 >= dateVal2);
}

Datum
date_cmp(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	if (dateVal1 < dateVal2)
		PG_RETURN_INT32(-1);
	else if (dateVal1 > dateVal2)
		PG_RETURN_INT32(1);
	PG_RETURN_INT32(0);
}

Datum
date_larger(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_DATEADT((dateVal1 > dateVal2) ? dateVal1 : dateVal2);
}

Datum
date_smaller(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_DATEADT((dateVal1 < dateVal2) ? dateVal1 : dateVal2);
}

/* Compute difference between two dates in days.
 */
Datum
date_mi(PG_FUNCTION_ARGS)
{
	DateADT		dateVal1 = PG_GETARG_DATEADT(0);
	DateADT		dateVal2 = PG_GETARG_DATEADT(1);

	PG_RETURN_INT32((int32) (dateVal1 - dateVal2));
}

/* Add a number of days to a date, giving a new date.
 * Must handle both positive and negative numbers of days.
 */
Datum
date_pli(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	int32		days = PG_GETARG_INT32(1);

	PG_RETURN_DATEADT(dateVal + days);
}

/* Subtract a number of days from a date, giving a new date.
 */
Datum
date_mii(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	int32		days = PG_GETARG_INT32(1);

	PG_RETURN_DATEADT(dateVal - days);
}

#if NOT_USED
/* date_pl_interval() and date_mi_interval() are probably
 * better implmented by converting the input date
 * to timestamp without time zone. So that is what we do
 * in pg_proc.h - thomas 2002-03-11
 */

/* Add an interval to a date, giving a new date.
 * Must handle both positive and negative intervals.
 */
Datum
date_pl_interval(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	struct tm	tt,
			   *tm = &tt;

	if (span->month != 0)
	{
		j2date(dateVal + POSTGRES_EPOCH_JDATE,
			   &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));
		tm->tm_mon += span->month;
		dateVal = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;
	}
	if (span->time != 0)
		dateVal += (span->time / 86400e0);

	PG_RETURN_DATEADT(dateVal);
}

/* Subtract an interval from a date, giving a new date.
 * Must handle both positive and negative intervals.
 */
Datum
date_mi_interval(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	struct tm	tt,
			   *tm = &tt;

	if (span->month != 0)
	{
		j2date(dateVal + POSTGRES_EPOCH_JDATE,
			   &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));
		tm->tm_mon -= span->month;
		dateVal = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;
	}
	if (span->time != 0)
		dateVal -= (span->time / 86400e0);

	PG_RETURN_DATEADT(dateVal);
}
#endif

/* date_timestamp()
 * Convert date to timestamp data type.
 */
Datum
date_timestamp(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	Timestamp	result;

#ifdef HAVE_INT64_TIMESTAMP
	/* date is days since 2000, timestamp is microseconds since same... */
	result = dateVal * INT64CONST(86400000000);
#else
	/* date is days since 2000, timestamp is seconds since same... */
	result = dateVal * 86400.0;
#endif

	PG_RETURN_TIMESTAMP(result);
}


/* timestamp_date()
 * Convert timestamp to date data type.
 */
Datum
timestamp_date(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	DateADT		result;
	struct tm	tt,
			   *tm = &tt;
	fsec_t		fsec;

	if (TIMESTAMP_NOT_FINITE(timestamp))
		PG_RETURN_NULL();

	if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) != 0)
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	result = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;

	PG_RETURN_DATEADT(result);
}


/* date_timestamptz()
 * Convert date to timestamp with time zone data type.
 */
Datum
date_timestamptz(PG_FUNCTION_ARGS)
{
	DateADT		dateVal = PG_GETARG_DATEADT(0);
	TimestampTz result;
	struct tm	tt,
			   *tm = &tt;

	j2date(dateVal + POSTGRES_EPOCH_JDATE,
		   &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));

	if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
	{
		int			tz;

		tm->tm_hour = 0;
		tm->tm_min = 0;
		tm->tm_sec = 0;
		tz = DetermineLocalTimeZone(tm);

#ifdef HAVE_INT64_TIMESTAMP
		result = (dateVal * INT64CONST(86400000000))
			+ (tz * INT64CONST(1000000));
#else
		result = dateVal * 86400.0 + tz;
#endif
	}
	else
	{
		/* Outside of range for timezone support, so assume UTC */
#ifdef HAVE_INT64_TIMESTAMP
		result = (dateVal * INT64CONST(86400000000));
#else
		result = dateVal * 86400.0;
#endif
	}

	PG_RETURN_TIMESTAMP(result);
}


/* timestamptz_date()
 * Convert timestamp with time zone to date data type.
 */
Datum
timestamptz_date(PG_FUNCTION_ARGS)
{
	TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
	DateADT		result;
	struct tm	tt,
			   *tm = &tt;
	fsec_t		fsec;
	int			tz;
	char	   *tzn;

	if (TIMESTAMP_NOT_FINITE(timestamp))
		PG_RETURN_NULL();

	if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) != 0)
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	result = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;

	PG_RETURN_DATEADT(result);
}


/* abstime_date()
 * Convert abstime to date data type.
 */
Datum
abstime_date(PG_FUNCTION_ARGS)
{
	AbsoluteTime abstime = PG_GETARG_ABSOLUTETIME(0);
	DateADT		result;
	struct tm	tt,
			   *tm = &tt;
	int			tz;

	switch (abstime)
	{
		case INVALID_ABSTIME:
		case NOSTART_ABSTIME:
		case NOEND_ABSTIME:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			   errmsg("cannot convert reserved abstime value to date")));

			/*
			 * pretend to drop through to make compiler think that result
			 * will be set
			 */

		default:
			abstime2tm(abstime, &tz, tm, NULL);
			result = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;
			break;
	}

	PG_RETURN_DATEADT(result);
}


/* date_text()
 * Convert date to text data type.
 */
Datum
date_text(PG_FUNCTION_ARGS)
{
	/* Input is a Date, but may as well leave it in Datum form */
	Datum		date = PG_GETARG_DATUM(0);
	text	   *result;
	char	   *str;
	int			len;

	str = DatumGetCString(DirectFunctionCall1(date_out, date));

	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

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

	pfree(str);

	PG_RETURN_TEXT_P(result);
}


/* text_date()
 * Convert text string to date.
 * Text type is not null terminated, so use temporary string
 *	then call the standard input routine.
 */
Datum
text_date(PG_FUNCTION_ARGS)
{
	text	   *str = PG_GETARG_TEXT_P(0);
	int			i;
	char	   *sp,
			   *dp,
				dstr[MAXDATELEN + 1];

	if (VARSIZE(str) - VARHDRSZ > MAXDATELEN)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
				 errmsg("invalid input syntax for type date: \"%s\"",
						VARDATA(str))));

	sp = VARDATA(str);
	dp = dstr;
	for (i = 0; i < (VARSIZE(str) - VARHDRSZ); i++)
		*dp++ = *sp++;
	*dp = '\0';

	return DirectFunctionCall1(date_in,
							   CStringGetDatum(dstr));
}


/*****************************************************************************
 *	 Time ADT
 *****************************************************************************/

Datum
time_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);
	TimeADT		result;
	fsec_t		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			tz;
	int			nf;
	int			dterr;
	char		lowstr[MAXDATELEN + 1];
	char	   *field[MAXDATEFIELDS];
	int			dtype;
	int			ftype[MAXDATEFIELDS];

	if (strlen(str) >= sizeof(lowstr))
		dterr = DTERR_BAD_FORMAT;
	else
		dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);