dt.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * dt.c
 *	  Functions for the built-in type "dt".
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /usr/local/cvsroot/pgsql/src/backend/utils/adt/dt.c,v 1.72.2.1 1999/08/02 05:24:51 scrappy Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <ctype.h>
#include <math.h>
#include <sys/types.h>
#include <errno.h>

#include "postgres.h"
#ifdef HAVE_FLOAT_H
#include <float.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifndef USE_POSIX_TIME
#include <sys/timeb.h>
#endif

#include "miscadmin.h"
#include "utils/builtins.h"

static int	DecodeDate(char *str, int fmask, int *tmask, struct tm * tm);
static int DecodeNumber(int flen, char *field,
	int fmask, int *tmask, struct tm * tm, double *fsec, int *is2digits);
static int DecodeNumberField(int len, char *str,
	int fmask, int *tmask, struct tm * tm, double *fsec, int *is2digits);
static int	DecodeSpecial(int field, char *lowtoken, int *val);
static int DecodeTime(char *str, int fmask, int *tmask,
		   struct tm * tm, double *fsec);
static int	DecodeTimezone(char *str, int *tzp);
static int	DecodeUnits(int field, char *lowtoken, int *val);
static int	EncodeSpecialDateTime(DateTime dt, char *str);
static datetkn *datebsearch(char *key, datetkn *base, unsigned int nel);
static DateTime dt2local(DateTime dt, int timezone);
static void dt2time(DateTime dt, int *hour, int *min, double *sec);
static int	j2day(int jd);
static double time2t(const int hour, const int min, const double sec);
static int	timespan2tm(TimeSpan span, struct tm * tm, float8 *fsec);
static int	tm2timespan(struct tm * tm, double fsec, TimeSpan *span);


#define USE_DATE_CACHE 1
#define ROUND_ALL 0

int			day_tab[2][13] = {
	{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0},
{31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0}};


char	   *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL};

char	   *days[] = {"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday", NULL};

/* TMODULO()
 * Macro to replace modf(), which is broken on some platforms.
 */
#define TMODULO(t,q,u) \
do { \
	q = ((t < 0)? ceil(t / u): floor(t / u)); \
	if (q != 0) \
		t -= rint(q * u); \
} while(0)

static void GetEpochTime(struct tm * tm);

#define UTIME_MINYEAR (1901)
#define UTIME_MINMONTH (12)
#define UTIME_MINDAY (14)
#define UTIME_MAXYEAR (2038)
#define UTIME_MAXMONTH (01)
#define UTIME_MAXDAY (18)

#define IS_VALID_UTIME(y,m,d) (((y > UTIME_MINYEAR) \
 || ((y == UTIME_MINYEAR) && ((m > UTIME_MINMONTH) \
  || ((m == UTIME_MINMONTH) && (d >= UTIME_MINDAY))))) \
 && ((y < UTIME_MAXYEAR) \
 || ((y == UTIME_MAXYEAR) && ((m < UTIME_MAXMONTH) \
  || ((m == UTIME_MAXMONTH) && (d <= UTIME_MAXDAY))))))


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

/* datetime_in()
 * Convert a string to internal form.
 */
DateTime   *
datetime_in(char *str)
{
	DateTime   *result;

	double		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			tz;
	int			dtype;
	int			nf;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		lowstr[MAXDATELEN + 1];

	if (!PointerIsValid(str))
		elog(ERROR, "Bad (null) datetime external representation", NULL);

	if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
	  || (DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz) != 0))
		elog(ERROR, "Bad datetime external representation '%s'", str);

	result = palloc(sizeof(DateTime));

	switch (dtype)
	{
		case DTK_DATE:
			if (tm2datetime(tm, fsec, &tz, result) != 0)
				elog(ERROR, "Datetime out of range '%s'", str);

#ifdef DATEDEBUG
			printf("datetime_in- date is %f\n", *result);
#endif

			break;

		case DTK_EPOCH:
			DATETIME_EPOCH(*result);
			break;

		case DTK_CURRENT:
			DATETIME_CURRENT(*result);
			break;

		case DTK_LATE:
			DATETIME_NOEND(*result);
			break;

		case DTK_EARLY:
			DATETIME_NOBEGIN(*result);
			break;

		case DTK_INVALID:
			DATETIME_INVALID(*result);
			break;

		default:
			elog(ERROR, "Internal coding error, can't input datetime '%s'", str);
	}

	return result;
}	/* datetime_in() */

/* datetime_out()
 * Convert a datetime to external form.
 */
char *
datetime_out(DateTime *dt)
{
	char	   *result;
	int			tz;
	struct tm	tt,
			   *tm = &tt;
	double		fsec;
	char	   *tzn;
	char		buf[MAXDATELEN + 1];

	if (!PointerIsValid(dt))
		return NULL;

	if (DATETIME_IS_RESERVED(*dt))
	{
		EncodeSpecialDateTime(*dt, buf);

	}
	else if (datetime2tm(*dt, &tz, tm, &fsec, &tzn) == 0)
	{
		EncodeDateTime(tm, fsec, &tz, &tzn, DateStyle, buf);

	}
	else
		EncodeSpecialDateTime(DT_INVALID, buf);

	result = palloc(strlen(buf) + 1);

	strcpy(result, buf);

	return result;
}	/* datetime_out() */


/* timespan_in()
 * Convert a string to internal form.
 *
 * External format(s):
 *	Uses the generic date/time parsing and decoding routines.
 */
TimeSpan   *
timespan_in(char *str)
{
	TimeSpan   *span;

	double		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			dtype;
	int			nf;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		lowstr[MAXDATELEN + 1];

	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;

	if (!PointerIsValid(str))
		elog(ERROR, "Bad (null) timespan external representation", NULL);

	if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
		|| (DecodeDateDelta(field, ftype, nf, &dtype, tm, &fsec) != 0))
		elog(ERROR, "Bad timespan external representation '%s'", str);

	span = palloc(sizeof(TimeSpan));

	switch (dtype)
	{
		case DTK_DELTA:
			if (tm2timespan(tm, fsec, span) != 0)
			{
#if NOT_USED
				TIMESPAN_INVALID(span);
#endif
				elog(ERROR, "Bad timespan external representation '%s'", str);
			}
			break;

		default:
			elog(ERROR, "Internal coding error, can't input timespan '%s'", str);
	}

	return span;
}	/* timespan_in() */

/* timespan_out()
 * Convert a time span to external form.
 */
char *
timespan_out(TimeSpan *span)
{
	char	   *result;

	struct tm	tt,
			   *tm = &tt;
	double		fsec;
	char		buf[MAXDATELEN + 1];

	if (!PointerIsValid(span))
		return NULL;

	if (timespan2tm(*span, tm, &fsec) != 0)
		return NULL;

	if (EncodeTimeSpan(tm, fsec, DateStyle, buf) != 0)
		elog(ERROR, "Unable to format timespan", NULL);

	result = palloc(strlen(buf) + 1);

	strcpy(result, buf);
	return result;
}	/* timespan_out() */


/*****************************************************************************
 *	 PUBLIC ROUTINES														 *
 *****************************************************************************/


bool
datetime_finite(DateTime *datetime)
{
	if (!PointerIsValid(datetime))
		return FALSE;

	return !DATETIME_NOT_FINITE(*datetime);
}	/* datetime_finite() */

bool
timespan_finite(TimeSpan *timespan)
{
	if (!PointerIsValid(timespan))
		return FALSE;

	return !TIMESPAN_NOT_FINITE(*timespan);
}	/* timespan_finite() */


/*----------------------------------------------------------
 *	Relational operators for datetime.
 *---------------------------------------------------------*/

static void
GetEpochTime(struct tm * tm)
{
	struct tm  *t0;
	time_t		epoch = 0;

	t0 = gmtime(&epoch);

	tm->tm_year = t0->tm_year;
	tm->tm_mon = t0->tm_mon;
	tm->tm_mday = t0->tm_mday;
	tm->tm_hour = t0->tm_hour;
	tm->tm_min = t0->tm_min;
	tm->tm_sec = t0->tm_sec;

	if (tm->tm_year < 1900)
		tm->tm_year += 1900;
	tm->tm_mon++;

#ifdef DATEDEBUG
	printf("GetEpochTime- %04d-%02d-%02d %02d:%02d:%02d\n",
		   tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
#endif

	return;
}	/* GetEpochTime() */

DateTime
SetDateTime(DateTime dt)
{
	struct tm	tt;

	if (DATETIME_IS_CURRENT(dt))
	{
		GetCurrentTime(&tt);
		tm2datetime(&tt, 0, NULL, &dt);
		dt = dt2local(dt, -CTimeZone);

#ifdef DATEDEBUG
		printf("SetDateTime- current time is %f\n", dt);
#endif
	}
	else
	{							/* if (DATETIME_IS_EPOCH(dt1)) */
		GetEpochTime(&tt);
		tm2datetime(&tt, 0, NULL, &dt);
#ifdef DATEDEBUG
		printf("SetDateTime- epoch time is %f\n", dt);
#endif
	}

	return dt;
}	/* SetDateTime() */

/*		datetime_relop	- is datetime1 relop datetime2
 */
bool
datetime_eq(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

	return dt1 == dt2;
}	/* datetime_eq() */

bool
datetime_ne(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

	return dt1 != dt2;
}	/* datetime_ne() */

bool
datetime_lt(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

	return dt1 < dt2;
}	/* datetime_lt() */

bool
datetime_gt(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

#ifdef DATEDEBUG
	printf("datetime_gt- %f %s greater than %f\n", dt1, ((dt1 > dt2) ? "is" : "is not"), dt2);
#endif
	return dt1 > dt2;
}	/* datetime_gt() */

bool
datetime_le(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

	return dt1 <= dt2;
}	/* datetime_le() */

bool
datetime_ge(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return FALSE;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1) || DATETIME_IS_INVALID(dt2))
		return FALSE;

	if (DATETIME_IS_RELATIVE(dt1))
		dt1 = SetDateTime(dt1);
	if (DATETIME_IS_RELATIVE(dt2))
		dt2 = SetDateTime(dt2);

	return dt1 >= dt2;
}	/* datetime_ge() */


/*		datetime_cmp	- 3-state comparison for datetime
 *		collate invalid datetime at the end
 */
int
datetime_cmp(DateTime *datetime1, DateTime *datetime2)
{
	DateTime	dt1,
				dt2;

	if (!PointerIsValid(datetime1) || !PointerIsValid(datetime2))
		return 0;

	dt1 = *datetime1;
	dt2 = *datetime2;

	if (DATETIME_IS_INVALID(dt1))
	{
		return (DATETIME_IS_INVALID(dt2) ? 0 : 1);

	}
	else if (DATETIME_IS_INVALID(dt2))
	{
		return -1;

	}
	else
	{
		if (DATETIME_IS_RELATIVE(dt1))
			dt1 = SetDateTime(dt1);
		if (DATETIME_IS_RELATIVE(dt2))
			dt2 = SetDateTime(dt2);
	}

	return ((dt1 < dt2) ? -1 : ((dt1 > dt2) ? 1 : 0));
}	/* datetime_cmp() */


/*		timespan_relop	- is timespan1 relop timespan2
 */
bool
timespan_eq(TimeSpan *timespan1, TimeSpan *timespan2)
{
	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

	if (TIMESPAN_IS_INVALID(*timespan1) || TIMESPAN_IS_INVALID(*timespan2))
		return FALSE;

	return ((timespan1->time == timespan2->time)
			&& (timespan1->month == timespan2->month));
}	/* timespan_eq() */

bool
timespan_ne(TimeSpan *timespan1, TimeSpan *timespan2)
{
	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

	if (TIMESPAN_IS_INVALID(*timespan1) || TIMESPAN_IS_INVALID(*timespan2))