/*-------------------------------------------------------------------------
 *
 * dt.c
 *	  Functions for the built-in type "dt".
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/dt.c,v 1.75 1999/07/16 05:00:08 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <stdio.h>
#include <ctype.h>
#include <math.h>
#include <string.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))
		return FALSE;

	return ((timespan1->time != timespan2->time)
			|| (timespan1->month != timespan2->month));
}	/* timespan_ne() */

bool
timespan_lt(TimeSpan *timespan1, TimeSpan *timespan2)
{
	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

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

	span1 = timespan1->time;
	if (timespan1->month != 0)
		span1 += (timespan1->month * (30.0 * 86400));
	span2 = timespan2->time;
	if (timespan2->month != 0)
		span2 += (timespan2->month * (30.0 * 86400));

	return span1 < span2;
}	/* timespan_lt() */

bool
timespan_gt(TimeSpan *timespan1, TimeSpan *timespan2)
{
	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

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

	span1 = timespan1->time;
	if (timespan1->month != 0)
		span1 += (timespan1->month * (30.0 * 86400));
	span2 = timespan2->time;
	if (timespan2->month != 0)
		span2 += (timespan2->month * (30.0 * 86400));

	return span1 > span2;
}	/* timespan_gt() */

bool
timespan_le(TimeSpan *timespan1, TimeSpan *timespan2)
{
	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

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

	span1 = timespan1->time;
	if (timespan1->month != 0)
		span1 += (timespan1->month * (30.0 * 86400));
	span2 = timespan2->time;
	if (timespan2->month != 0)
		span2 += (timespan2->month * (30.0 * 86400));

	return span1 <= span2;
}	/* timespan_le() */

bool
timespan_ge(TimeSpan *timespan1, TimeSpan *timespan2)
{
	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return FALSE;

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

	span1 = timespan1->time;
	if (timespan1->month != 0)
		span1 += (timespan1->month * (30.0 * 86400));
	span2 = timespan2->time;
	if (timespan2->month != 0)
		span2 += (timespan2->month * (30.0 * 86400));

	return span1 >= span2;
}	/* timespan_ge() */


/*		timespan_cmp	- 3-state comparison for timespan
 */
int
timespan_cmp(TimeSpan *timespan1, TimeSpan *timespan2)
{
	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return 0;

	if (TIMESPAN_IS_INVALID(*timespan1))
	{
		return TIMESPAN_IS_INVALID(*timespan2) ? 0 : 1;

	}
	else if (TIMESPAN_IS_INVALID(*timespan2))
		return -1;

	span1 = timespan1->time;
	if (timespan1->month != 0)
		span1 += (timespan1->month * (30.0 * 86400));
	span2 = timespan2->time;
	if (timespan2->month != 0)
		span2 += (timespan2->month * (30.0 * 86400));

	return (span1 < span2) ? -1 : (span1 > span2) ? 1 : 0;
}	/* timespan_cmp() */


/*----------------------------------------------------------
 *	"Arithmetic" operators on date/times.
 *		datetime_foo	returns foo as an object (pointer) that
 *						can be passed between languages.
 *		datetime_xx		is an internal routine which returns the
 *						actual value.
 *---------------------------------------------------------*/

DateTime   *
datetime_smaller(DateTime *datetime1, DateTime *datetime2)
{
	DateTime   *result;

	DateTime	dt1,
				dt2;

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

	dt1 = *datetime1;
	dt2 = *datetime2;

	result = palloc(sizeof(DateTime));

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

	if (DATETIME_IS_INVALID(dt1))
		*result = dt2;
	else if (DATETIME_IS_INVALID(dt2))
		*result = dt1;
	else
		*result = ((dt2 < dt1) ? dt2 : dt1);

	return result;
}	/* datetime_smaller() */

DateTime   *
datetime_larger(DateTime *datetime1, DateTime *datetime2)
{
	DateTime   *result;

	DateTime	dt1,
				dt2;

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

	dt1 = *datetime1;
	dt2 = *datetime2;

	result = palloc(sizeof(DateTime));

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

	if (DATETIME_IS_INVALID(dt1))
		*result = dt2;
	else if (DATETIME_IS_INVALID(dt2))
		*result = dt1;
	else
		*result = ((dt2 > dt1) ? dt2 : dt1);

	return result;
}	/* datetime_larger() */


TimeSpan   *
datetime_mi(DateTime *datetime1, DateTime *datetime2)
{
	TimeSpan   *result;

	DateTime	dt1,
				dt2;

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

	dt1 = *datetime1;
	dt2 = *datetime2;

	result = palloc(sizeof(TimeSpan));

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

#ifdef DATEDEBUG
	printf("datetime_mi- evaluate %f - %f\n", dt1, dt2);
#endif

	if (DATETIME_IS_INVALID(dt1)
		|| DATETIME_IS_INVALID(dt2))
	{
		DATETIME_INVALID(result->time);

	}
	else
		result->time = JROUND(dt1 - dt2);
	result->month = 0;

	return result;
}	/* datetime_mi() */


/* datetime_pl_span()
 * Add a timespan to a datetime data type.
 * Note that timespan has provisions for qualitative year/month
 *	units, so try to do the right thing with them.
 * To add a month, increment the month, and use the same day of month.
 * Then, if the next month has fewer days, set the day of month
 *	to the last day of month.
 */
DateTime   *
datetime_pl_span(DateTime *datetime, TimeSpan *span)
{
	DateTime   *result;
	DateTime	dt;
	int			tz;
	char	   *tzn;

	if ((!PointerIsValid(datetime)) || (!PointerIsValid(span)))
		return NULL;

	result = palloc(sizeof(DateTime));

#ifdef DATEDEBUG
	printf("datetime_pl_span- add %f to %d %f\n", *datetime, span->month, span->time);
#endif

	if (DATETIME_NOT_FINITE(*datetime))
	{
		*result = *datetime;

	}
	else if (TIMESPAN_IS_INVALID(*span))
	{
		DATETIME_INVALID(*result);

	}
	else
	{
		dt = (DATETIME_IS_RELATIVE(*datetime) ? SetDateTime(*datetime) : *datetime);

#ifdef ROUND_ALL
		dt = JROUND(dt + span->time);
#else
		dt += span->time;
#endif

		if (span->month != 0)
		{
			struct tm	tt,
					   *tm = &tt;
			double		fsec;

			if (datetime2tm(dt, &tz, tm, &fsec, &tzn) == 0)
			{
#ifdef DATEDEBUG
				printf("datetime_pl_span- date was %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
				tm->tm_mon += span->month;
				if (tm->tm_mon > 12)
				{
					tm->tm_year += ((tm->tm_mon - 1) / 12);
					tm->tm_mon = (((tm->tm_mon - 1) % 12) + 1);
				}
				else if (tm->tm_mon < 1)
				{
					tm->tm_year += ((tm->tm_mon / 12) - 1);
					tm->tm_mon = ((tm->tm_mon % 12) + 12);
				}

				/* adjust for end of month boundary problems... */
				if (tm->tm_mday > day_tab[isleap(tm->tm_year)][tm->tm_mon - 1])
					tm->tm_mday = (day_tab[isleap(tm->tm_year)][tm->tm_mon - 1]);

#ifdef DATEDEBUG
				printf("datetime_pl_span- date becomes %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
				if (tm2datetime(tm, fsec, &tz, &dt) != 0)
					elog(ERROR, "Unable to add datetime and timespan", NULL);

			}
			else
				DATETIME_INVALID(dt);
		}

		*result = dt;
	}

	return result;
}	/* datetime_pl_span() */

DateTime   *
datetime_mi_span(DateTime *datetime, TimeSpan *span)
{
	DateTime   *result;
	TimeSpan	tspan;

	if (!PointerIsValid(datetime) || !PointerIsValid(span))
		return NULL;

	tspan.month = -span->month;
	tspan.time = -span->time;

	result = datetime_pl_span(datetime, &tspan);

	return result;
}	/* datetime_mi_span() */


TimeSpan   *
timespan_um(TimeSpan *timespan)
{
	TimeSpan   *result;

	if (!PointerIsValid(timespan))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	result->time = -(timespan->time);
	result->month = -(timespan->month);

	return result;
}	/* timespan_um() */


TimeSpan   *
timespan_smaller(TimeSpan *timespan1, TimeSpan *timespan2)
{
	TimeSpan   *result;

	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	if (TIMESPAN_IS_INVALID(*timespan1))
	{
		result->time = timespan2->time;
		result->month = timespan2->month;

	}
	else if (TIMESPAN_IS_INVALID(*timespan2))
	{
		result->time = timespan1->time;
		result->month = timespan1->month;

	}
	else
	{
		span1 = timespan1->time;
		if (timespan1->month != 0)
			span1 += (timespan1->month * (30.0 * 86400));
		span2 = timespan2->time;
		if (timespan2->month != 0)
			span2 += (timespan2->month * (30.0 * 86400));

#ifdef DATEDEBUG
		printf("timespan_smaller- months %d %d times %f %f spans %f %f\n",
			   timespan1->month, timespan2->month, timespan1->time, timespan2->time, span1, span2);
#endif

		if (span2 < span1)
		{
			result->time = timespan2->time;
			result->month = timespan2->month;

		}
		else
		{
			result->time = timespan1->time;
			result->month = timespan1->month;
		}
	}

	return result;
}	/* timespan_smaller() */

TimeSpan   *
timespan_larger(TimeSpan *timespan1, TimeSpan *timespan2)
{
	TimeSpan   *result;

	double		span1,
				span2;

	if (!PointerIsValid(timespan1) || !PointerIsValid(timespan2))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	if (TIMESPAN_IS_INVALID(*timespan1))
	{
		result->time = timespan2->time;
		result->month = timespan2->month;

	}
	else if (TIMESPAN_IS_INVALID(*timespan2))
	{
		result->time = timespan1->time;
		result->month = timespan1->month;

	}
	else
	{
		span1 = timespan1->time;
		if (timespan1->month != 0)
			span1 += (timespan1->month * (30.0 * 86400));
		span2 = timespan2->time;
		if (timespan2->month != 0)
			span2 += (timespan2->month * (30.0 * 86400));

#ifdef DATEDEBUG
		printf("timespan_larger- months %d %d times %f %f spans %f %f\n",
			   timespan1->month, timespan2->month, timespan1->time, timespan2->time, span1, span2);
#endif

		if (span2 > span1)
		{
			result->time = timespan2->time;
			result->month = timespan2->month;

		}
		else
		{
			result->time = timespan1->time;
			result->month = timespan1->month;
		}
	}

	return result;
}	/* timespan_larger() */


TimeSpan   *
timespan_pl(TimeSpan *span1, TimeSpan *span2)
{
	TimeSpan   *result;

	if ((!PointerIsValid(span1)) || (!PointerIsValid(span2)))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	result->month = (span1->month + span2->month);
	result->time = JROUND(span1->time + span2->time);

	return result;
}	/* timespan_pl() */

TimeSpan   *
timespan_mi(TimeSpan *span1, TimeSpan *span2)
{
	TimeSpan   *result;

	if ((!PointerIsValid(span1)) || (!PointerIsValid(span2)))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	result->month = (span1->month - span2->month);
	result->time = JROUND(span1->time - span2->time);

	return result;
}	/* timespan_mi() */

TimeSpan   *
timespan_div(TimeSpan *span1, float8 *arg2)
{
	TimeSpan   *result;

	if ((!PointerIsValid(span1)) || (!PointerIsValid(arg2)))
		return NULL;

	if (!PointerIsValid(result = palloc(sizeof(TimeSpan))))
		elog(ERROR, "Memory allocation failed, can't divide timespans", NULL);

	if (*arg2 == 0.0)
		elog(ERROR, "timespan_div:  divide by 0.0 error");

	result->month = rint(span1->month / *arg2);
	result->time = JROUND(span1->time / *arg2);

	return result;
}	/* timespan_div() */

/* datetime_age()
 * Calculate time difference while retaining year/month fields.
 * Note that this does not result in an accurate absolute time span
 *	since year and month are out of context once the arithmetic
 *	is done.
 */
TimeSpan   *
datetime_age(DateTime *datetime1, DateTime *datetime2)
{
	TimeSpan   *result;

	DateTime	dt1,
				dt2;
	double		fsec,
				fsec1,
				fsec2;
	struct tm	tt,
			   *tm = &tt;
	struct tm	tt1,
			   *tm1 = &tt1;
	struct tm	tt2,
			   *tm2 = &tt2;

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

	result = palloc(sizeof(TimeSpan));

	dt1 = *datetime1;
	dt2 = *datetime2;

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

	if (DATETIME_IS_INVALID(dt1)
		|| DATETIME_IS_INVALID(dt2))
	{
		DATETIME_INVALID(result->time);

	}
	else if ((datetime2tm(dt1, NULL, tm1, &fsec1, NULL) == 0)
			 && (datetime2tm(dt2, NULL, tm2, &fsec2, NULL) == 0))
	{
		fsec = (fsec1 - fsec2);
		tm->tm_sec = (tm1->tm_sec - tm2->tm_sec);
		tm->tm_min = (tm1->tm_min - tm2->tm_min);
		tm->tm_hour = (tm1->tm_hour - tm2->tm_hour);
		tm->tm_mday = (tm1->tm_mday - tm2->tm_mday);
		tm->tm_mon = (tm1->tm_mon - tm2->tm_mon);
		tm->tm_year = (tm1->tm_year - tm2->tm_year);

		/* flip sign if necessary... */
		if (dt1 < dt2)
		{
			fsec = -fsec;
			tm->tm_sec = -tm->tm_sec;
			tm->tm_min = -tm->tm_min;
			tm->tm_hour = -tm->tm_hour;
			tm->tm_mday = -tm->tm_mday;
			tm->tm_mon = -tm->tm_mon;
			tm->tm_year = -tm->tm_year;
		}

		if (tm->tm_sec < 0)
		{
			tm->tm_sec += 60;
			tm->tm_min--;
		}

		if (tm->tm_min < 0)
		{
			tm->tm_min += 60;
			tm->tm_hour--;
		}

		if (tm->tm_hour < 0)
		{
			tm->tm_hour += 24;
			tm->tm_mday--;
		}

		if (tm->tm_mday < 0)
		{
			if (dt1 < dt2)
			{
				tm->tm_mday += day_tab[isleap(tm1->tm_year)][tm1->tm_mon - 1];
				tm->tm_mon--;
			}
			else
			{
				tm->tm_mday += day_tab[isleap(tm2->tm_year)][tm2->tm_mon - 1];
				tm->tm_mon--;
			}
		}

		if (tm->tm_mon < 0)
		{
			tm->tm_mon += 12;
			tm->tm_year--;
		}

		/* recover sign if necessary... */
		if (dt1 < dt2)
		{
			fsec = -fsec;
			tm->tm_sec = -tm->tm_sec;
			tm->tm_min = -tm->tm_min;
			tm->tm_hour = -tm->tm_hour;
			tm->tm_mday = -tm->tm_mday;
			tm->tm_mon = -tm->tm_mon;
			tm->tm_year = -tm->tm_year;
		}

		if (tm2timespan(tm, fsec, result) != 0)
			elog(ERROR, "Unable to decode datetime", NULL);

	}
	else
		elog(ERROR, "Unable to decode datetime", NULL);

	return result;
}	/* datetime_age() */


/*----------------------------------------------------------
 *	Conversion operators.
 *---------------------------------------------------------*/


/* datetime_text()
 * Convert datetime to text data type.
 */
text *
datetime_text(DateTime *datetime)
{
	text	   *result;
	char	   *str;
	int			len;

	if (!PointerIsValid(datetime))
		return NULL;

	str = datetime_out(datetime);

	if (!PointerIsValid(str))
		return NULL;

	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

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

	pfree(str);

	return result;
}	/* datetime_text() */


/* text_datetime()
 * Convert text string to datetime.
 * Text type is not null terminated, so use temporary string
 *	then call the standard input routine.
 */
DateTime   *
text_datetime(text *str)
{
	DateTime   *result;
	int			i;
	char	   *sp,
			   *dp,
				dstr[MAXDATELEN + 1];

	if (!PointerIsValid(str))
		return NULL;

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

	result = datetime_in(dstr);

	return result;
}	/* text_datetime() */


/* timespan_text()
 * Convert timespan to text data type.
 */
text *
timespan_text(TimeSpan *timespan)
{
	text	   *result;
	char	   *str;
	int			len;

	if (!PointerIsValid(timespan))
		return NULL;

	str = timespan_out(timespan);

	if (!PointerIsValid(str))
		return NULL;

	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

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

	pfree(str);

	return result;
}	/* timespan_text() */


/* text_timespan()
 * Convert text string to timespan.
 * Text type may not be null terminated, so copy to temporary string
 *	then call the standard input routine.
 */
TimeSpan   *
text_timespan(text *str)
{
	TimeSpan   *result;
	int			i;
	char	   *sp,
			   *dp,
				dstr[MAXDATELEN + 1];

	if (!PointerIsValid(str))
		return NULL;

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

	result = timespan_in(dstr);

	return result;
}	/* text_timespan() */

/* datetime_trunc()
 * Extract specified field from datetime.
 */
DateTime   *
datetime_trunc(text *units, DateTime *datetime)
{
	DateTime   *result;

	DateTime	dt;
	int			tz;
	int			type,
				val;
	int			i;
	char	   *up,
			   *lp,
				lowunits[MAXDATELEN + 1];
	double		fsec;
	char	   *tzn;
	struct tm	tt,
			   *tm = &tt;

	if ((!PointerIsValid(units)) || (!PointerIsValid(datetime)))
		return NULL;

	result = palloc(sizeof(DateTime));

	up = VARDATA(units);
	lp = lowunits;
	for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
		*lp++ = tolower(*up++);
	*lp = '\0';

	type = DecodeUnits(0, lowunits, &val);

#ifdef DATEDEBUG
	if (type == IGNORE)
		strcpy(lowunits, "(unknown)");
	printf("datetime_trunc- units %s type=%d value=%d\n", lowunits, type, val);
#endif

	if (DATETIME_NOT_FINITE(*datetime))
	{
#if NOT_USED
/* should return null but Postgres doesn't like that currently. - tgl 97/06/12 */
		elog(ERROR, "Datetime is not finite", NULL);
#endif
		*result = 0;

	}
	else
	{
		dt = (DATETIME_IS_RELATIVE(*datetime) ? SetDateTime(*datetime) : *datetime);

		if ((type == UNITS) && (datetime2tm(dt, &tz, tm, &fsec, &tzn) == 0))
		{
			switch (val)
			{
				case DTK_MILLENIUM:
					tm->tm_year = (tm->tm_year / 1000) * 1000;
				case DTK_CENTURY:
					tm->tm_year = (tm->tm_year / 100) * 100;
				case DTK_DECADE:
					tm->tm_year = (tm->tm_year / 10) * 10;
				case DTK_YEAR:
					tm->tm_mon = 1;
				case DTK_QUARTER:
					tm->tm_mon = (3 * (tm->tm_mon / 4)) + 1;
				case DTK_MONTH:
					tm->tm_mday = 1;
				case DTK_DAY:
					tm->tm_hour = 0;
				case DTK_HOUR:
					tm->tm_min = 0;
				case DTK_MINUTE:
					tm->tm_sec = 0;
				case DTK_SECOND:
					fsec = 0;
					break;

				case DTK_MILLISEC:
					fsec = rint(fsec * 1000) / 1000;
					break;

				case DTK_MICROSEC:
					fsec = rint(fsec * 1000000) / 1000000;
					break;

				default:
					elog(ERROR, "Datetime units '%s' not supported", lowunits);
					result = NULL;
			}

			if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
			{
#ifdef USE_POSIX_TIME
				tm->tm_isdst = -1;
				tm->tm_year -= 1900;
				tm->tm_mon -= 1;
				tm->tm_isdst = -1;
				mktime(tm);
				tm->tm_year += 1900;
				tm->tm_mon += 1;

#if defined(HAVE_TM_ZONE)
				tz = -(tm->tm_gmtoff);	/* tm_gmtoff is Sun/DEC-ism */
#elif defined(HAVE_INT_TIMEZONE)

#ifdef __CYGWIN__
				tz = (tm->tm_isdst ? (_timezone - 3600) : _timezone);
#else
				tz = (tm->tm_isdst ? (timezone - 3600) : timezone);
#endif

#else
#error USE_POSIX_TIME is defined but neither HAVE_TM_ZONE or HAVE_INT_TIMEZONE are defined
#endif

#else							/* !USE_POSIX_TIME */
				tz = CTimeZone;
#endif
			}
			else
			{
				tm->tm_isdst = 0;
				tz = 0;
			}

			if (tm2datetime(tm, fsec, &tz, result) != 0)
				elog(ERROR, "Unable to truncate datetime to '%s'", lowunits);

#if NOT_USED
		}
		else if ((type == RESERV) && (val == DTK_EPOCH))
		{
			DATETIME_EPOCH(*result);
			*result = dt - SetDateTime(*result);
#endif

		}
		else
		{
			elog(ERROR, "Datetime units '%s' not recognized", lowunits);
			result = NULL;
		}
	}

	return result;
}	/* datetime_trunc() */

/* timespan_trunc()
 * Extract specified field from timespan.
 */
TimeSpan   *
timespan_trunc(text *units, TimeSpan *timespan)
{
	TimeSpan   *result;

	int			type,
				val;
	int			i;
	char	   *up,
			   *lp,
				lowunits[MAXDATELEN + 1];
	double		fsec;
	struct tm	tt,
			   *tm = &tt;

	if ((!PointerIsValid(units)) || (!PointerIsValid(timespan)))
		return NULL;

	result = palloc(sizeof(TimeSpan));

	up = VARDATA(units);
	lp = lowunits;
	for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
		*lp++ = tolower(*up++);
	*lp = '\0';

	type = DecodeUnits(0, lowunits, &val);

#ifdef DATEDEBUG
	if (type == IGNORE)
		strcpy(lowunits, "(unknown)");
	printf("timespan_trunc- units %s type=%d value=%d\n", lowunits, type, val);
#endif

	if (TIMESPAN_IS_INVALID(*timespan))
	{
#if NOT_USED
		elog(ERROR, "Timespan is not finite", NULL);
#endif
		result = NULL;

	}
	else if (type == UNITS)
	{

		if (timespan2tm(*timespan, tm, &fsec) == 0)
		{
			switch (val)
			{
				case DTK_MILLENIUM:
					tm->tm_year = (tm->tm_year / 1000) * 1000;
				case DTK_CENTURY:
					tm->tm_year = (tm->tm_year / 100) * 100;
				case DTK_DECADE:
					tm->tm_year = (tm->tm_year / 10) * 10;
				case DTK_YEAR:
					tm->tm_mon = 0;
				case DTK_QUARTER:
					tm->tm_mon = (3 * (tm->tm_mon / 4));
				case DTK_MONTH:
					tm->tm_mday = 0;
				case DTK_DAY:
					tm->tm_hour = 0;
				case DTK_HOUR:
					tm->tm_min = 0;
				case DTK_MINUTE:
					tm->tm_sec = 0;
				case DTK_SECOND:
					fsec = 0;
					break;

				case DTK_MILLISEC:
					fsec = rint(fsec * 1000) / 1000;
					break;

				case DTK_MICROSEC:
					fsec = rint(fsec * 1000000) / 1000000;
					break;

				default:
					elog(ERROR, "Timespan units '%s' not supported", lowunits);
					result = NULL;
			}

			if (tm2timespan(tm, fsec, result) != 0)
				elog(ERROR, "Unable to truncate timespan to '%s'", lowunits);

		}
		else
		{
			elog(NOTICE, "Timespan out of range", NULL);
			result = NULL;
		}

#if NOT_USED
	}
	else if ((type == RESERV) && (val == DTK_EPOCH))
	{
		*result = timespan->time;
		if (timespan->month != 0)
		{
			*result += ((365.25 * 86400) * (timespan->month / 12));
			*result += ((30 * 86400) * (timespan->month % 12));
		}
#endif

	}
	else
	{
		elog(ERROR, "Timespan units '%s' not recognized", units);
		result = NULL;
	}

	return result;
}	/* timespan_trunc() */


/* datetime_part()
 * Extract specified field from datetime.
 */
float64
datetime_part(text *units, DateTime *datetime)
{
	float64		result;

	DateTime	dt;
	int			tz;
	int			type,
				val;
	int			i;
	char	   *up,
			   *lp,
				lowunits[MAXDATELEN + 1];
	double		dummy;
	double		fsec;
	char	   *tzn;
	struct tm	tt,
			   *tm = &tt;

	if ((!PointerIsValid(units)) || (!PointerIsValid(datetime)))
		return NULL;

	result = palloc(sizeof(float64data));

	up = VARDATA(units);
	lp = lowunits;
	for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
		*lp++ = tolower(*up++);
	*lp = '\0';

	type = DecodeUnits(0, lowunits, &val);
	if (type == IGNORE)
		type = DecodeSpecial(0, lowunits, &val);

#ifdef DATEDEBUG
	if (type == IGNORE)
		strcpy(lowunits, "(unknown)");
	printf("datetime_part- units %s type=%d value=%d\n", lowunits, type, val);
#endif

	if (DATETIME_NOT_FINITE(*datetime))
	{
#if NOT_USED
/* should return null but Postgres doesn't like that currently. - tgl 97/06/12 */
		elog(ERROR, "Datetime is not finite", NULL);
#endif
		*result = 0;

	}
	else
	{
		dt = (DATETIME_IS_RELATIVE(*datetime) ? SetDateTime(*datetime) : *datetime);

		if ((type == UNITS) && (datetime2tm(dt, &tz, tm, &fsec, &tzn) == 0))
		{
			switch (val)
			{
				case DTK_TZ:
					*result = tz;
					break;

				case DTK_TZ_MINUTE:
					*result = tz / 60;
					TMODULO(*result, dummy, 60e0);
					break;

				case DTK_TZ_HOUR:
					dummy = tz;
					TMODULO(dummy, *result, 3600e0);
					break;

				case DTK_MICROSEC:
					*result = (fsec * 1000000);
					break;

				case DTK_MILLISEC:
					*result = (fsec * 1000);
					break;

				case DTK_SECOND:
					*result = (tm->tm_sec + fsec);
					break;

				case DTK_MINUTE:
					*result = tm->tm_min;
					break;

				case DTK_HOUR:
					*result = tm->tm_hour;
					break;

				case DTK_DAY:
					*result = tm->tm_mday;
					break;

				case DTK_MONTH:
					*result = tm->tm_mon;
					break;

				case DTK_QUARTER:
					*result = (tm->tm_mon / 4) + 1;
					break;

				case DTK_YEAR:
					*result = tm->tm_year;
					break;

				case DTK_DECADE:
					*result = (tm->tm_year / 10);
					break;

				case DTK_CENTURY:
					*result = (tm->tm_year / 100);
					break;

				case DTK_MILLENIUM:
					*result = (tm->tm_year / 1000);
					break;

				default:
					elog(ERROR, "Datetime units '%s' not supported", lowunits);
					*result = 0;
			}

		}
		else if (type == RESERV)
		{
			switch (val)
			{
				case DTK_EPOCH:
					DATETIME_EPOCH(*result);
					*result = dt - SetDateTime(*result);
					break;

				case DTK_DOW:
					if (datetime2tm(dt, &tz, tm, &fsec, &tzn) != 0)
						elog(ERROR, "Unable to encode datetime", NULL);

					*result = j2day(date2j(tm->tm_year, tm->tm_mon, tm->tm_mday));
					break;

				case DTK_DOY:
					if (datetime2tm(dt, &tz, tm, &fsec, &tzn) != 0)
						elog(ERROR, "Unable to encode datetime", NULL);

					*result = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday)
							   - date2j(tm->tm_year, 1, 1) + 1);
					break;

				default:
					elog(ERROR, "Datetime units '%s' not supported", lowunits);
					*result = 0;
			}

		}
		else
		{
			elog(ERROR, "Datetime units '%s' not recognized", lowunits);
			*result = 0;
		}
	}

	return result;
}	/* datetime_part() */


/* timespan_part()
 * Extract specified field from timespan.
 */
float64
timespan_part(text *units, TimeSpan *timespan)
{
	float64		result;

	int			type,
				val;
	int			i;
	char	   *up,
			   *lp,
				lowunits[MAXDATELEN + 1];
	double		fsec;
	struct tm	tt,
			   *tm = &tt;

	if ((!PointerIsValid(units)) || (!PointerIsValid(timespan)))
		return NULL;

	result = palloc(sizeof(float64data));

	up = VARDATA(units);
	lp = lowunits;
	for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
		*lp++ = tolower(*up++);
	*lp = '\0';

	type = DecodeUnits(0, lowunits, &val);
	if (type == IGNORE)
		type = DecodeSpecial(0, lowunits, &val);

#ifdef DATEDEBUG
	if (type == IGNORE)
		strcpy(lowunits, "(unknown)");
	printf("timespan_part- units %s type=%d value=%d\n", lowunits, type, val);
#endif

	if (TIMESPAN_IS_INVALID(*timespan))
	{
#if NOT_USED
		elog(ERROR, "Timespan is not finite", NULL);
#endif
		*result = 0;

	}
	else if (type == UNITS)
	{

		if (timespan2tm(*timespan, tm, &fsec) == 0)
		{
			switch (val)
			{
				case DTK_MICROSEC:
					*result = (fsec * 1000000);
					break;

				case DTK_MILLISEC:
					*result = (fsec * 1000);
					break;

				case DTK_SECOND:
					*result = (tm->tm_sec + fsec);
					break;

				case DTK_MINUTE:
					*result = tm->tm_min;
					break;

				case DTK_HOUR:
					*result = tm->tm_hour;
					break;

				case DTK_DAY:
					*result = tm->tm_mday;
					break;

				case DTK_MONTH:
					*result = tm->tm_mon;
					break;

				case DTK_QUARTER:
					*result = (tm->tm_mon / 4) + 1;
					break;

				case DTK_YEAR:
					*result = tm->tm_year;
					break;

				case DTK_DECADE:
					*result = (tm->tm_year / 10);
					break;

				case DTK_CENTURY:
					*result = (tm->tm_year / 100);
					break;

				case DTK_MILLENIUM:
					*result = (tm->tm_year / 1000);
					break;

				default:
					elog(ERROR, "Timespan units '%s' not yet supported", units);
					result = NULL;
			}

		}
		else
		{
			elog(NOTICE, "Timespan out of range", NULL);
			*result = 0;
		}

	}
	else if ((type == RESERV) && (val == DTK_EPOCH))
	{
		*result = timespan->time;
		if (timespan->month != 0)
		{
			*result += ((365.25 * 86400) * (timespan->month / 12));
			*result += ((30 * 86400) * (timespan->month % 12));
		}

	}
	else
	{
		elog(ERROR, "Timespan units '%s' not recognized", units);
		*result = 0;
	}

	return result;
}	/* timespan_part() */


/* datetime_zone()
 * Encode datetime type with specified time zone.
 */
text *
datetime_zone(text *zone, DateTime *datetime)
{
	text	   *result;

	DateTime	dt;
	int			tz;
	int			type,
				val;
	int			i;
	char	   *up,
			   *lp,
				lowzone[MAXDATELEN + 1];
	char	   *tzn,
				upzone[MAXDATELEN + 1];
	double		fsec;
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];
	int			len;

	if ((!PointerIsValid(zone)) || (!PointerIsValid(datetime)))
		return NULL;

	up = VARDATA(zone);
	lp = lowzone;
	for (i = 0; i < (VARSIZE(zone) - VARHDRSZ); i++)
		*lp++ = tolower(*up++);
	*lp = '\0';

	type = DecodeSpecial(0, lowzone, &val);

#ifdef DATEDEBUG
	if (type == IGNORE)
		strcpy(lowzone, "(unknown)");
	printf("datetime_zone- zone %s type=%d value=%d\n", lowzone, type, val);
#endif

	if (DATETIME_NOT_FINITE(*datetime))
	{

		/*
		 * could return null but Postgres doesn't like that currently. -
		 * tgl 97/06/12
		 */
		elog(ERROR, "Datetime is not finite", NULL);
		result = NULL;

	}
	else if ((type == TZ) || (type == DTZ))
	{
		tm->tm_isdst = ((type == DTZ) ? 1 : 0);
		tz = val * 60;

		dt = (DATETIME_IS_RELATIVE(*datetime) ? SetDateTime(*datetime) : *datetime);
		dt = dt2local(dt, tz);

		if (datetime2tm(dt, NULL, tm, &fsec, NULL) != 0)
			elog(ERROR, "Datetime not legal", NULL);

		up = upzone;
		lp = lowzone;
		for (i = 0; *lp != '\0'; i++)
			*up++ = toupper(*lp++);
		*up = '\0';

		tzn = upzone;
		EncodeDateTime(tm, fsec, &tz, &tzn, DateStyle, buf);

		len = (strlen(buf) + VARHDRSZ);

		result = palloc(len);

		VARSIZE(result) = len;
		memmove(VARDATA(result), buf, (len - VARHDRSZ));

	}
	else
	{
		elog(ERROR, "Time zone '%s' not recognized", lowzone);
		result = NULL;
	}

	return result;
}	/* datetime_zone() */


/*****************************************************************************
 *	 PRIVATE ROUTINES														 *
 *****************************************************************************/

/* definitions for squeezing values into "value" */
#define ABS_SIGNBIT		(char) 0200
#define VALMASK			(char) 0177
#define NEG(n)			((n)|ABS_SIGNBIT)
#define SIGNEDCHAR(c)	((c)&ABS_SIGNBIT? -((c)&VALMASK): (c))
#define FROMVAL(tp)		(-SIGNEDCHAR((tp)->value) * 10) /* uncompress */
#define TOVAL(tp, v)	((tp)->value = ((v) < 0? NEG((-(v))/10): (v)/10))

/*
 * to keep this table reasonably small, we divide the lexval for TZ and DTZ
 * entries by 10 and truncate the text field at MAXTOKLEN characters.
 * the text field is not guaranteed to be NULL-terminated.
 */
static datetkn datetktbl[] = {
/*		text			token	lexval */
	{EARLY, RESERV, DTK_EARLY}, /* "-infinity" reserved for "early time" */
	{"acsst", DTZ, 63},			/* Cent. Australia */
	{"acst", TZ, 57},			/* Cent. Australia */
	{DA_D, ADBC, AD},			/* "ad" for years >= 0 */
	{"abstime", IGNORE, 0},		/* "abstime" for pre-v6.1 "Invalid
								 * Abstime" */
	{"adt", DTZ, NEG(18)},		/* Atlantic Daylight Time */
	{"aesst", DTZ, 66},			/* E. Australia */
	{"aest", TZ, 60},			/* Australia Eastern Std Time */
	{"ahst", TZ, NEG(60)},		/* Alaska-Hawaii Std Time */
	{"allballs", RESERV, DTK_ZULU},		/* 00:00:00 */
	{"am", AMPM, AM},
	{"apr", MONTH, 4},
	{"april", MONTH, 4},
	{"ast", TZ, NEG(24)},		/* Atlantic Std Time (Canada) */
	{"at", IGNORE, 0},			/* "at" (throwaway) */
	{"aug", MONTH, 8},
	{"august", MONTH, 8},
	{"awsst", DTZ, 54},			/* W. Australia */
	{"awst", TZ, 48},			/* W. Australia */
	{DB_C, ADBC, BC},			/* "bc" for years < 0 */
	{"bst", TZ, 6},				/* British Summer Time */
	{"bt", TZ, 18},				/* Baghdad Time */
	{"cadt", DTZ, 63},			/* Central Australian DST */
	{"cast", TZ, 57},			/* Central Australian ST */
	{"cat", TZ, NEG(60)},		/* Central Alaska Time */
	{"cct", TZ, 48},			/* China Coast */
	{"cdt", DTZ, NEG(30)},		/* Central Daylight Time */
	{"cet", TZ, 6},				/* Central European Time */
	{"cetdst", DTZ, 12},		/* Central European Dayl.Time */
	{"cst", TZ, NEG(36)},		/* Central Standard Time */
	{DCURRENT, RESERV, DTK_CURRENT},	/* "current" is always now */
	{"dec", MONTH, 12},
	{"december", MONTH, 12},
	{"dnt", TZ, 6},				/* Dansk Normal Tid */
	{"dow", RESERV, DTK_DOW},	/* day of week */
	{"doy", RESERV, DTK_DOY},	/* day of year */
	{"dst", DTZMOD, 6},
	{"east", TZ, NEG(60)},		/* East Australian Std Time */
	{"edt", DTZ, NEG(24)},		/* Eastern Daylight Time */
	{"eet", TZ, 12},			/* East. Europe, USSR Zone 1 */
	{"eetdst", DTZ, 18},		/* Eastern Europe */
	{EPOCH, RESERV, DTK_EPOCH}, /* "epoch" reserved for system epoch time */
#if USE_AUSTRALIAN_RULES
	{"est", TZ, 60},			/* Australia Eastern Std Time */
#else
	{"est", TZ, NEG(30)},		/* Eastern Standard Time */
#endif
	{"feb", MONTH, 2},
	{"february", MONTH, 2},
	{"fri", DOW, 5},
	{"friday", DOW, 5},
	{"fst", TZ, 6},				/* French Summer Time */
	{"fwt", DTZ, 12},			/* French Winter Time  */
	{"gmt", TZ, 0},				/* Greenwish Mean Time */
	{"gst", TZ, 60},			/* Guam Std Time, USSR Zone 9 */
	{"hdt", DTZ, NEG(54)},		/* Hawaii/Alaska */
	{"hmt", DTZ, 18},			/* Hellas ? ? */
	{"hst", TZ, NEG(60)},		/* Hawaii Std Time */
	{"idle", TZ, 72},			/* Intl. Date Line, East */
	{"idlw", TZ, NEG(72)},		/* Intl. Date Line, West */
	{LATE, RESERV, DTK_LATE},	/* "infinity" reserved for "late time" */
	{INVALID, RESERV, DTK_INVALID},
	/* "invalid" reserved for invalid time */
	{"ist", TZ, 12},			/* Israel */
	{"it", TZ, 21},				/* Iran Time */
	{"jan", MONTH, 1},
	{"january", MONTH, 1},
	{"jst", TZ, 54},			/* Japan Std Time,USSR Zone 8 */
	{"jt", TZ, 45},				/* Java Time */
	{"jul", MONTH, 7},
	{"july", MONTH, 7},
	{"jun", MONTH, 6},
	{"june", MONTH, 6},
	{"kst", TZ, 54},			/* Korea Standard Time */
	{"ligt", TZ, 60},			/* From Melbourne, Australia */
	{"mar", MONTH, 3},
	{"march", MONTH, 3},
	{"may", MONTH, 5},
	{"mdt", DTZ, NEG(36)},		/* Mountain Daylight Time */
	{"mest", DTZ, 12},			/* Middle Europe Summer Time */
	{"met", TZ, 6},				/* Middle Europe Time */
	{"metdst", DTZ, 12},		/* Middle Europe Daylight Time */
	{"mewt", TZ, 6},			/* Middle Europe Winter Time */
	{"mez", TZ, 6},				/* Middle Europe Zone */
	{"mon", DOW, 1},
	{"monday", DOW, 1},
	{"mst", TZ, NEG(42)},		/* Mountain Standard Time */
	{"mt", TZ, 51},				/* Moluccas Time */
	{"ndt", DTZ, NEG(15)},		/* Nfld. Daylight Time */
	{"nft", TZ, NEG(21)},		/* Newfoundland Standard Time */
	{"nor", TZ, 6},				/* Norway Standard Time */
	{"nov", MONTH, 11},
	{"november", MONTH, 11},
	{NOW, RESERV, DTK_NOW},		/* current transaction time */
	{"nst", TZ, NEG(21)},		/* Nfld. Standard Time */
	{"nt", TZ, NEG(66)},		/* Nome Time */
	{"nzdt", DTZ, 78},			/* New Zealand Daylight Time */
	{"nzst", TZ, 72},			/* New Zealand Standard Time */
	{"nzt", TZ, 72},			/* New Zealand Time */
	{"oct", MONTH, 10},
	{"october", MONTH, 10},
	{"on", IGNORE, 0},			/* "on" (throwaway) */
	{"pdt", DTZ, NEG(42)},		/* Pacific Daylight Time */
	{"pm", AMPM, PM},
	{"pst", TZ, NEG(48)},		/* Pacific Standard Time */
	{"sadt", DTZ, 63},			/* S. Australian Dayl. Time */
	{"sast", TZ, 57},			/* South Australian Std Time */
	{"sat", DOW, 6},
	{"saturday", DOW, 6},
	{"sep", MONTH, 9},
	{"sept", MONTH, 9},
	{"september", MONTH, 9},
	{"set", TZ, NEG(6)},		/* Seychelles Time ?? */
	{"sst", DTZ, 12},			/* Swedish Summer Time */
	{"sun", DOW, 0},
	{"sunday", DOW, 0},
	{"swt", TZ, 6},				/* Swedish Winter Time	*/
	{"thu", DOW, 4},
	{"thur", DOW, 4},
	{"thurs", DOW, 4},
	{"thursday", DOW, 4},
	{TODAY, RESERV, DTK_TODAY}, /* midnight */
	{TOMORROW, RESERV, DTK_TOMORROW},	/* tomorrow midnight */
	{"tue", DOW, 2},
	{"tues", DOW, 2},
	{"tuesday", DOW, 2},
	{"undefined", RESERV, DTK_INVALID}, /* "undefined" pre-v6.1 invalid
										 * time */
	{"ut", TZ, 0},
	{"utc", TZ, 0},
	{"wadt", DTZ, 48},			/* West Australian DST */
	{"wast", TZ, 42},			/* West Australian Std Time */
	{"wat", TZ, NEG(6)},		/* West Africa Time */
	{"wdt", DTZ, 54},			/* West Australian DST */
	{"wed", DOW, 3},
	{"wednesday", DOW, 3},
	{"weds", DOW, 3},
	{"wet", TZ, 0},				/* Western Europe */
	{"wetdst", DTZ, 6},			/* Western Europe */
	{"wst", TZ, 48},			/* West Australian Std Time */
	{"ydt", DTZ, NEG(48)},		/* Yukon Daylight Time */
	{YESTERDAY, RESERV, DTK_YESTERDAY}, /* yesterday midnight */
	{"yst", TZ, NEG(54)},		/* Yukon Standard Time */
	{"zp4", TZ, NEG(24)},		/* GMT +4  hours. */
	{"zp5", TZ, NEG(30)},		/* GMT +5  hours. */
	{"zp6", TZ, NEG(36)},		/* GMT +6  hours. */
	{"z", RESERV, DTK_ZULU},	/* 00:00:00 */
	{ZULU, RESERV, DTK_ZULU},	/* 00:00:00 */
};

static unsigned int szdatetktbl = sizeof datetktbl / sizeof datetktbl[0];

static datetkn deltatktbl[] = {
/*		text			token	lexval */
	{"@", IGNORE, 0},			/* postgres relative time prefix */
	{DAGO, AGO, 0},				/* "ago" indicates negative time offset */
	{"c", UNITS, DTK_CENTURY},	/* "century" relative time units */
	{"cent", UNITS, DTK_CENTURY},		/* "century" relative time units */
	{"centuries", UNITS, DTK_CENTURY},	/* "centuries" relative time units */
	{DCENTURY, UNITS, DTK_CENTURY},		/* "century" relative time units */
	{"d", UNITS, DTK_DAY},		/* "day" relative time units */
	{DDAY, UNITS, DTK_DAY},		/* "day" relative time units */
	{"days", UNITS, DTK_DAY},	/* "days" relative time units */
	{"dec", UNITS, DTK_DECADE}, /* "decade" relative time units */
	{"decs", UNITS, DTK_DECADE},/* "decades" relative time units */
	{DDECADE, UNITS, DTK_DECADE},		/* "decade" relative time units */
	{"decades", UNITS, DTK_DECADE},		/* "decades" relative time units */
	{"h", UNITS, DTK_HOUR},		/* "hour" relative time units */
	{DHOUR, UNITS, DTK_HOUR},	/* "hour" relative time units */
	{"hours", UNITS, DTK_HOUR}, /* "hours" relative time units */
	{"hr", UNITS, DTK_HOUR},	/* "hour" relative time units */
	{"hrs", UNITS, DTK_HOUR},	/* "hours" relative time units */
	{INVALID, RESERV, DTK_INVALID},		/* "invalid" reserved for invalid
										 * time */
	{"m", UNITS, DTK_MINUTE},	/* "minute" relative time units */
	{"microsecon", UNITS, DTK_MICROSEC},		/* "microsecond" relative
												 * time units */
	{"mil", UNITS, DTK_MILLENIUM},		/* "millenium" relative time units */
	{"mils", UNITS, DTK_MILLENIUM},		/* "millenia" relative time units */
	{"millenia", UNITS, DTK_MILLENIUM}, /* "millenia" relative time units */
	{DMILLENIUM, UNITS, DTK_MILLENIUM}, /* "millenium" relative time units */
	{"millisecon", UNITS, DTK_MILLISEC},		/* relative time units */
	{"min", UNITS, DTK_MINUTE}, /* "minute" relative time units */
	{"mins", UNITS, DTK_MINUTE},/* "minutes" relative time units */
	{"mins", UNITS, DTK_MINUTE},/* "minutes" relative time units */
	{DMINUTE, UNITS, DTK_MINUTE},		/* "minute" relative time units */
	{"minutes", UNITS, DTK_MINUTE},		/* "minutes" relative time units */
	{"mon", UNITS, DTK_MONTH},	/* "months" relative time units */
	{"mons", UNITS, DTK_MONTH}, /* "months" relative time units */
	{DMONTH, UNITS, DTK_MONTH}, /* "month" relative time units */
	{"months", UNITS, DTK_MONTH},
	{"ms", UNITS, DTK_MILLISEC},
	{"msec", UNITS, DTK_MILLISEC},
	{DMILLISEC, UNITS, DTK_MILLISEC},
	{"mseconds", UNITS, DTK_MILLISEC},
	{"msecs", UNITS, DTK_MILLISEC},
	{"qtr", UNITS, DTK_QUARTER},/* "quarter" relative time */
	{DQUARTER, UNITS, DTK_QUARTER},		/* "quarter" relative time */
	{"reltime", IGNORE, 0},		/* for pre-v6.1 "Undefined Reltime" */
	{"s", UNITS, DTK_SECOND},
	{"sec", UNITS, DTK_SECOND},
	{DSECOND, UNITS, DTK_SECOND},
	{"seconds", UNITS, DTK_SECOND},
	{"secs", UNITS, DTK_SECOND},
	{DTIMEZONE, UNITS, DTK_TZ}, /* "timezone" time offset */
	{"tz", UNITS, DTK_TZ},		/* "timezone" time offset */
	{"tz_hour", UNITS, DTK_TZ_HOUR},	/* timezone hour units */
	{"tz_minute", UNITS, DTK_TZ_MINUTE},		/* timezone minutes units */
	{"undefined", RESERV, DTK_INVALID}, /* pre-v6.1 invalid time */
	{"us", UNITS, DTK_MICROSEC},/* "microsecond" relative time units */
	{"usec", UNITS, DTK_MICROSEC},		/* "microsecond" relative time
										 * units */
	{DMICROSEC, UNITS, DTK_MICROSEC},	/* "microsecond" relative time
										 * units */
	{"useconds", UNITS, DTK_MICROSEC},	/* "microseconds" relative time
										 * units */
	{"usecs", UNITS, DTK_MICROSEC},		/* "microseconds" relative time
										 * units */
	{"w", UNITS, DTK_WEEK},		/* "week" relative time units */
	{DWEEK, UNITS, DTK_WEEK},	/* "week" relative time units */
	{"weeks", UNITS, DTK_WEEK}, /* "weeks" relative time units */
	{"y", UNITS, DTK_YEAR},		/* "year" relative time units */
	{DYEAR, UNITS, DTK_YEAR},	/* "year" relative time units */
	{"years", UNITS, DTK_YEAR}, /* "years" relative time units */
	{"yr", UNITS, DTK_YEAR},	/* "year" relative time units */
	{"yrs", UNITS, DTK_YEAR},	/* "years" relative time units */
};

static unsigned int szdeltatktbl = sizeof deltatktbl / sizeof deltatktbl[0];

#if USE_DATE_CACHE
datetkn    *datecache[MAXDATEFIELDS] = {NULL};

datetkn    *deltacache[MAXDATEFIELDS] = {NULL};

#endif


/*
 * Calendar time to Julian date conversions.
 * Julian date is commonly used in astronomical applications,
 *	since it is numerically accurate and computationally simple.
 * The algorithms here will accurately convert between Julian day
 *	and calendar date for all non-negative Julian days
 *	(i.e. from Nov 23, -4713 on).
 *
 * Ref: Explanatory Supplement to the Astronomical Almanac, 1992.
 *	University Science Books, 20 Edgehill Rd. Mill Valley CA 94941.
 *
 * Use the algorithm by Henry Fliegel, a former NASA/JPL colleague
 *	now at Aerospace Corp. (hi, Henry!)
 *
 * These routines will be used by other date/time packages - tgl 97/02/25
 */

int
date2j(int y, int m, int d)
{
	int			m12 = (m - 14) / 12;

	return ((1461 * (y + 4800 + m12)) / 4 + (367 * (m - 2 - 12 * (m12))) / 12
			- (3 * ((y + 4900 + m12) / 100)) / 4 + d - 32075);
}	/* date2j() */

void
j2date(int jd, int *year, int *month, int *day)
{
	int			j,
				y,
				m,
				d;

	int			i,
				l,
				n;

	l = jd + 68569;
	n = (4 * l) / 146097;
	l -= (146097 * n + 3) / 4;
	i = (4000 * (l + 1)) / 1461001;
	l += 31 - (1461 * i) / 4;
	j = (80 * l) / 2447;
	d = l - (2447 * j) / 80;
	l = j / 11;
	m = (j + 2) - (12 * l);
	y = 100 * (n - 49) + i + l;

	*year = y;
	*month = m;
	*day = d;
	return;
}	/* j2date() */

static int
j2day(int date)
{
	int			day;

	day = (date + 1) % 7;

	return day;
}	/* j2day() */


/* datetime2tm()
 * Convert datetime data type to POSIX time structure.
 * Note that year is _not_ 1900-based, but is an explicit full value.
 * Also, month is one-based, _not_ zero-based.
 * Returns:
 *	 0 on success
 *	-1 on out of range
 *
 * For dates within the system-supported time_t range, convert to the
 *	local time zone. If out of this range, leave as GMT. - tgl 97/05/27
 */
int
datetime2tm(DateTime dt, int *tzp, struct tm * tm, double *fsec, char **tzn)
{
	double		date,
				date0,
				time,
				sec;
	time_t		utime;

#ifdef USE_POSIX_TIME
	struct tm  *tx;

#endif

	date0 = date2j(2000, 1, 1);

	time = dt;
	TMODULO(time, date, 86400e0);

	if (time < 0)
	{
		time += 86400;
		date -= 1;
	}

	/* Julian day routine does not work for negative Julian days */
	if (date < -date0)
		return -1;

	/* add offset to go from J2000 back to standard Julian date */
	date += date0;

#ifdef DATEDEBUG
	printf("datetime2tm- date is %f (%f %f)\n", dt, date, time);
#endif

	j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
	dt2time(time, &tm->tm_hour, &tm->tm_min, &sec);

#ifdef DATEDEBUG
	printf("datetime2tm- date is %d.%02d.%02d\n", tm->tm_year, tm->tm_mon, tm->tm_mday);
	printf("datetime2tm- time is %02d:%02d:%02.0f\n", tm->tm_hour, tm->tm_min, sec);
#endif

	*fsec = JROUND(sec);
	TMODULO(*fsec, tm->tm_sec, 1e0);

#ifdef DATEDEBUG
	printf("datetime2tm- time is %02d:%02d:%02d %.7f\n", tm->tm_hour, tm->tm_min, tm->tm_sec, *fsec);
#endif

	if (tzp != NULL)
	{
		if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
		{
			utime = (dt + (date0 - date2j(1970, 1, 1)) * 86400);

#ifdef USE_POSIX_TIME
			tx = localtime(&utime);
#ifdef DATEDEBUG
#if defined(HAVE_TM_ZONE)
			printf("datetime2tm- (localtime) %d.%02d.%02d %02d:%02d:%02.0f %s dst=%d\n",
				   tx->tm_year, tx->tm_mon, tx->tm_mday, tx->tm_hour, tx->tm_min, sec,
				   tx->tm_zone, tx->tm_isdst);
#elif defined(HAVE_INT_TIMEZONE)
			printf("datetime2tm- (localtime) %d.%02d.%02d %02d:%02d:%02.0f %s %s dst=%d\n",
				   tx->tm_year, tx->tm_mon, tx->tm_mday, tx->tm_hour, tx->tm_min, sec,
				   tzname[0], tzname[1], tx->tm_isdst);
#else
#error USE_POSIX_TIME is defined but neither HAVE_TM_ZONE or HAVE_INT_TIMEZONE are defined
#endif
#endif
			tm->tm_year = tx->tm_year + 1900;
			tm->tm_mon = tx->tm_mon + 1;
			tm->tm_mday = tx->tm_mday;
			tm->tm_hour = tx->tm_hour;
			tm->tm_min = tx->tm_min;
#if NOT_USED
/* XXX HACK
 * Argh! My Linux box puts in a 1 second offset for dates less than 1970
 *	but only if the seconds field was non-zero. So, don't copy the seconds
 *	field and instead carry forward from the original - tgl 97/06/18
 * Note that GNU/Linux uses the standard freeware zic package as do
 *	many other platforms so this may not be GNU/Linux/ix86-specific.
 */
			tm->tm_sec = tx->tm_sec;
#endif
			tm->tm_isdst = tx->tm_isdst;

#if defined(HAVE_TM_ZONE)
			tm->tm_gmtoff = tx->tm_gmtoff;
			tm->tm_zone = tx->tm_zone;

			*tzp = -(tm->tm_gmtoff);	/* tm_gmtoff is Sun/DEC-ism */
			if (tzn != NULL)
				*tzn = (char *) tm->tm_zone;
#elif defined(HAVE_INT_TIMEZONE)
#ifdef __CYGWIN__
			*tzp = (tm->tm_isdst ? (_timezone - 3600) : _timezone);
#else
			*tzp = (tm->tm_isdst ? (timezone - 3600) : timezone);
#endif
			if (tzn != NULL)
				*tzn = tzname[(tm->tm_isdst > 0)];
#else
#error USE_POSIX_TIME is defined but neither HAVE_TM_ZONE or HAVE_INT_TIMEZONE are defined
#endif

#else							/* !USE_POSIX_TIME */
			*tzp = CTimeZone;	/* V7 conventions; don't know timezone? */
			if (tzn != NULL)
				*tzn = CTZName;
#endif

		}
		else
		{
			*tzp = 0;
			tm->tm_isdst = 0;
			if (tzn != NULL)
				*tzn = NULL;
		}

		dt = dt2local(dt, *tzp);

	}
	else
	{
		tm->tm_isdst = 0;
		if (tzn != NULL)
			*tzn = NULL;
	}

#ifdef DATEDEBUG
	printf("datetime2tm- date is %d.%02d.%02d\n", tm->tm_year, tm->tm_mon, tm->tm_mday);
	printf("datetime2tm- time is %02d:%02d:%02d %.7f\n", tm->tm_hour, tm->tm_min, tm->tm_sec, *fsec);
#endif

#ifdef DATEDEBUG
#ifdef USE_POSIX_TIME
#if defined(HAVE_TM_ZONE)
	printf("datetime2tm- timezone is %s; offset is %d\n",
		   tm->tm_zone, ((tzp != NULL) ? *tzp : 0));
#elif defined(HAVE_INT_TIMEZONE)
	printf("datetime2tm- timezone is %s; offset is %d (%d); daylight is %d\n",
		   tzname[tm->tm_isdst != 0], ((tzp != NULL) ? *tzp : 0), CTimeZone, CDayLight);
#endif
#endif
#endif

	return 0;
}	/* datetime2tm() */


/* tm2datetime()
 * Convert a tm structure to a datetime data type.
 * Note that year is _not_ 1900-based, but is an explicit full value.
 * Also, month is one-based, _not_ zero-based.
 */
int
tm2datetime(struct tm * tm, double fsec, int *tzp, DateTime *result)
{

	double		date,
				time;

	/* Julian day routines are not correct for negative Julian days */
	if (!IS_VALID_JULIAN(tm->tm_year, tm->tm_mon, tm->tm_mday))
		return -1;

	date = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - date2j(2000, 1, 1);
	time = time2t(tm->tm_hour, tm->tm_min, (tm->tm_sec + fsec));
	*result = (date * 86400 + time);
#ifdef DATEDEBUG
	printf("tm2datetime- date is %f (%f %f %d)\n", *result, date, time, (((tm->tm_hour * 60) + tm->tm_min) * 60 + tm->tm_sec));
	printf("tm2datetime- time is %f %02d:%02d:%02d %f\n", time, tm->tm_hour, tm->tm_min, tm->tm_sec, fsec);
#endif
	if (tzp != NULL)
		*result = dt2local(*result, -(*tzp));

	return 0;
}	/* tm2datetime() */


/* timespan2tm()
 * Convert a timespan data type to a tm structure.
 */
static int
timespan2tm(TimeSpan span, struct tm * tm, float8 *fsec)
{
	double		time;

	if (span.month != 0)
	{
		tm->tm_year = span.month / 12;
		tm->tm_mon = span.month % 12;

	}
	else
	{
		tm->tm_year = 0;
		tm->tm_mon = 0;
	}

#ifdef ROUND_ALL
	time = JROUND(span.time);
#else
	time = span.time;
#endif

	TMODULO(time, tm->tm_mday, 86400e0);
	TMODULO(time, tm->tm_hour, 3600e0);
	TMODULO(time, tm->tm_min, 60e0);
	TMODULO(time, tm->tm_sec, 1e0);
	*fsec = time;

#ifdef DATEDEBUG
	printf("timespan2tm- %d %f = %04d-%02d-%02d %02d:%02d:%02d %.2f\n", span.month, span.time,
		   tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, *fsec);
#endif

	return 0;
}	/* timespan2tm() */

static int
tm2timespan(struct tm * tm, double fsec, TimeSpan *span)
{
	span->month = ((tm->tm_year * 12) + tm->tm_mon);
	span->time = ((((((tm->tm_mday * 24) + tm->tm_hour) * 60) + tm->tm_min) * 60) + tm->tm_sec);
	span->time = JROUND(span->time + fsec);

#ifdef DATEDEBUG
	printf("tm2timespan- %d %f = %04d-%02d-%02d %02d:%02d:%02d %.2f\n", span->month, span->time,
		   tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, fsec);
#endif

	return 0;
}	/* tm2timespan() */


static DateTime
dt2local(DateTime dt, int tz)
{
	dt -= tz;
	dt = JROUND(dt);
	return dt;
}	/* dt2local() */

static double
time2t(const int hour, const int min, const double sec)
{
	return (((hour * 60) + min) * 60) + sec;
}	/* time2t() */

static void
dt2time(DateTime jd, int *hour, int *min, double *sec)
{
	double		time;

	time = jd;

	*hour = (time / 3600);
	time -= ((*hour) * 3600);
	*min = (time / 60);
	time -= ((*min) * 60);
	*sec = JROUND(time);

	return;
}	/* dt2time() */


/*
 * parse and convert date in timestr (the normal interface)
 *
 * Returns the number of seconds since epoch (J2000)
 */

/* ParseDateTime()
 * Break string into tokens based on a date/time context.
 */
int
ParseDateTime(char *timestr, char *lowstr,
			  char **field, int *ftype, int maxfields, int *numfields)
{
	int			nf = 0;
	char	   *cp = timestr;
	char	   *lp = lowstr;

#ifdef DATEDEBUG
	printf("ParseDateTime- input string is %s\n", timestr);
#endif
	/* outer loop through fields */
	while (*cp != '\0')
	{
		field[nf] = lp;

		/* leading digit? then date or time */
		if (isdigit(*cp) || (*cp == '.'))
		{
			*lp++ = *cp++;
			while (isdigit(*cp))
				*lp++ = *cp++;
			/* time field? */
			if (*cp == ':')
			{
				ftype[nf] = DTK_TIME;
				while (isdigit(*cp) || (*cp == ':') || (*cp == '.'))
					*lp++ = *cp++;

			}
			/* date field? allow embedded text month */
			else if ((*cp == '-') || (*cp == '/') || (*cp == '.'))
			{
				ftype[nf] = DTK_DATE;
				while (isalnum(*cp) || (*cp == '-') || (*cp == '/') || (*cp == '.'))
					*lp++ = tolower(*cp++);

			}

			/*
			 * otherwise, number only and will determine year, month, or
			 * day later
			 */
			else
				ftype[nf] = DTK_NUMBER;

		}

		/*
		 * text? then date string, month, day of week, special, or
		 * timezone
		 */
		else if (isalpha(*cp))
		{
			ftype[nf] = DTK_STRING;
			*lp++ = tolower(*cp++);
			while (isalpha(*cp))
				*lp++ = tolower(*cp++);

			/* full date string with leading text month? */
			if ((*cp == '-') || (*cp == '/') || (*cp == '.'))
			{
				ftype[nf] = DTK_DATE;
				while (isdigit(*cp) || (*cp == '-') || (*cp == '/') || (*cp == '.'))
					*lp++ = tolower(*cp++);
			}

			/* skip leading spaces */
		}
		else if (isspace(*cp))
		{
			cp++;
			continue;

			/* sign? then special or numeric timezone */
		}
		else if ((*cp == '+') || (*cp == '-'))
		{
			*lp++ = *cp++;
			/* soak up leading whitespace */
			while (isspace(*cp))
				cp++;
			/* numeric timezone? */
			if (isdigit(*cp))
			{
				ftype[nf] = DTK_TZ;
				*lp++ = *cp++;
				while (isdigit(*cp) || (*cp == ':'))
					*lp++ = *cp++;

				/* special? */
			}
			else if (isalpha(*cp))
			{
				ftype[nf] = DTK_SPECIAL;
				*lp++ = tolower(*cp++);
				while (isalpha(*cp))
					*lp++ = tolower(*cp++);

				/* otherwise something wrong... */
			}
			else
				return -1;

			/* ignore punctuation but use as delimiter */
		}
		else if (ispunct(*cp))
		{
			cp++;
			continue;

		}
		else
			return -1;

		/* force in a delimiter */
		*lp++ = '\0';
		nf++;
		if (nf > MAXDATEFIELDS)
			return -1;
#ifdef DATEDEBUG
		printf("ParseDateTime- set field[%d] to %s type %d\n", (nf - 1), field[nf - 1], ftype[nf - 1]);
#endif
	}

	*numfields = nf;

	return 0;
}	/* ParseDateTime() */


/* DecodeDateTime()
 * Interpret previously parsed fields for general date and time.
 * Return 0 if full date, 1 if only time, and -1 if problems.
 *		External format(s):
 *				"<weekday> <month>-<day>-<year> <hour>:<minute>:<second>"
 *				"Fri Feb-7-1997 15:23:27"
 *				"Feb-7-1997 15:23:27"
 *				"2-7-1997 15:23:27"
 *				"1997-2-7 15:23:27"
 *				"1997.038 15:23:27"		(day of year 1-366)
 *		Also supports input in compact time:
 *				"970207 152327"
 *				"97038 152327"
 *
 * Use the system-provided functions to get the current time zone
 *	if not specified in the input string.
 * If the date is outside the time_t system-supported time range,
 *	then assume GMT time zone. - tgl 97/05/27
 */
int
DecodeDateTime(char **field, int *ftype, int nf,
			   int *dtype, struct tm * tm, double *fsec, int *tzp)
{
	int			fmask = 0,
				tmask,
				type;
	int			i;
	int			flen,
				val;
	int			mer = HR24;
	int			haveTextMonth = FALSE;
	int			is2digits = FALSE;
	int			bc = FALSE;

	*dtype = DTK_DATE;
	tm->tm_hour = 0;
	tm->tm_min = 0;
	tm->tm_sec = 0;
	*fsec = 0;
	tm->tm_isdst = -1;			/* don't know daylight savings time status
								 * apriori */
	if (tzp != NULL)
		*tzp = 0;

	for (i = 0; i < nf; i++)
	{
#ifdef DATEDEBUG
		printf("DecodeDateTime- field[%d] is %s (type %d)\n", i, field[i], ftype[i]);
#endif
		switch (ftype[i])
		{
			case DTK_DATE:
				if (DecodeDate(field[i], fmask, &tmask, tm) != 0)
					return -1;
				break;

			case DTK_TIME:
				if (DecodeTime(field[i], fmask, &tmask, tm, fsec) != 0)
					return -1;

				/*
				 * check upper limit on hours; other limits checked in
				 * DecodeTime()
				 */
				if (tm->tm_hour > 23)
					return -1;
				break;

			case DTK_TZ:
				if (tzp == NULL)
					return -1;
				if (DecodeTimezone(field[i], tzp) != 0)
					return -1;
				tmask = DTK_M(TZ);
				break;

			case DTK_NUMBER:
				flen = strlen(field[i]);

				/*
				 * long numeric string and either no date or no time read
				 * yet? then interpret as a concatenated date or time...
				 */
				if ((flen > 4) && !((fmask & DTK_DATE_M) && (fmask & DTK_TIME_M)))
				{
					if (DecodeNumberField(flen, field[i], fmask, &tmask, tm, fsec, &is2digits) != 0)
						return -1;

				}
				/* otherwise it is a single date/time field... */
				else
				{
					if (DecodeNumber(flen, field[i], fmask, &tmask, tm, fsec, &is2digits) != 0)
						return -1;
				}
				break;

			case DTK_STRING:
			case DTK_SPECIAL:
				type = DecodeSpecial(i, field[i], &val);
#ifdef DATEDEBUG
				printf("DecodeDateTime- special field[%d] %s type=%d value=%d\n", i, field[i], type, val);
#endif
				if (type == IGNORE)
					continue;

				tmask = DTK_M(type);
				switch (type)
				{
					case RESERV:
#ifdef DATEDEBUG
						printf("DecodeDateTime- RESERV field %s value is %d\n", field[i], val);
#endif
						switch (val)
						{
							case DTK_NOW:
								tmask = (DTK_DATE_M | DTK_TIME_M | DTK_M(TZ));
								*dtype = DTK_DATE;
								GetCurrentTime(tm);
								if (tzp != NULL)
									*tzp = CTimeZone;
								break;

							case DTK_YESTERDAY:
								tmask = DTK_DATE_M;
								*dtype = DTK_DATE;
								GetCurrentTime(tm);
								j2date((date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - 1),
								&tm->tm_year, &tm->tm_mon, &tm->tm_mday);
								tm->tm_hour = 0;
								tm->tm_min = 0;
								tm->tm_sec = 0;
								break;

							case DTK_TODAY:
								tmask = DTK_DATE_M;
								*dtype = DTK_DATE;
								GetCurrentTime(tm);
								tm->tm_hour = 0;
								tm->tm_min = 0;
								tm->tm_sec = 0;
								break;

							case DTK_TOMORROW:
								tmask = DTK_DATE_M;
								*dtype = DTK_DATE;
								GetCurrentTime(tm);
								j2date((date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + 1),
								&tm->tm_year, &tm->tm_mon, &tm->tm_mday);
								tm->tm_hour = 0;
								tm->tm_min = 0;
								tm->tm_sec = 0;
								break;

							case DTK_ZULU:
								tmask = (DTK_TIME_M | DTK_M(TZ));
								*dtype = DTK_DATE;
								tm->tm_hour = 0;
								tm->tm_min = 0;
								tm->tm_sec = 0;
								if (tzp != NULL)
									*tzp = 0;
								break;

							default:
								*dtype = val;
						}

						break;

					case MONTH:
#ifdef DATEDEBUG
						printf("DecodeDateTime- month field %s value is %d\n", field[i], val);
#endif

						/*
						 * already have a (numeric) month? then see if we
						 * can substitute...
						 */
						if ((fmask & DTK_M(MONTH)) && (!haveTextMonth)
							&& (!(fmask & DTK_M(DAY)))
							&& ((tm->tm_mon >= 1) && (tm->tm_mon <= 31)))
						{
							tm->tm_mday = tm->tm_mon;
							tmask = DTK_M(DAY);
#ifdef DATEDEBUG
							printf("DecodeNumber- misidentified month previously; assign as day %d\n", tm->tm_mday);
#endif
						}
						haveTextMonth = TRUE;
						tm->tm_mon = val;
						break;

					case DTZMOD:

						/*
						 * daylight savings time modifier (solves "MET
						 * DST" syntax)
						 */
						tmask |= DTK_M(DTZ);
						tm->tm_isdst = 1;
						if (tzp == NULL)
							return -1;
						*tzp += val * 60;
						break;

					case DTZ:

						/*
						 * set mask for TZ here _or_ check for DTZ later
						 * when getting default timezone
						 */
						tmask |= DTK_M(TZ);
						tm->tm_isdst = 1;
						if (tzp == NULL)
							return -1;
						*tzp = val * 60;
						break;

					case TZ:
						tm->tm_isdst = 0;
						if (tzp == NULL)
							return -1;
						*tzp = val * 60;
						break;

					case IGNORE:
						break;

					case AMPM:
						mer = val;
						break;

					case ADBC:
						bc = (val == BC);
						break;

					case DOW:
						tm->tm_wday = val;
						break;

					default:
						return -1;
				}
				break;

			default:
				return -1;
		}

#ifdef DATEDEBUG
		printf("DecodeDateTime- field[%d] %s (%08x/%08x) value is %d\n",
			   i, field[i], fmask, tmask, val);
#endif

		if (tmask & fmask)
			return -1;
		fmask |= tmask;
	}

	/* there is no year zero in AD/BC notation; i.e. "1 BC" == year 0 */
	if (bc)
	{
		if (tm->tm_year > 0)
			tm->tm_year = -(tm->tm_year - 1);
		else
			elog(ERROR, "Inconsistant use of year %04d and 'BC'", tm->tm_year);
	}
	else if (is2digits)
	{
		if (tm->tm_year < 70)
			tm->tm_year += 2000;
		else if (tm->tm_year < 100)
			tm->tm_year += 1900;
	}

	if ((mer != HR24) && (tm->tm_hour > 12))
		return -1;
	if ((mer == AM) && (tm->tm_hour == 12))
		tm->tm_hour = 0;
	else if ((mer == PM) && (tm->tm_hour != 12))
		tm->tm_hour += 12;

#ifdef DATEDEBUG
	printf("DecodeDateTime- mask %08x (%08x)", fmask, DTK_DATE_M);
	printf(" set y%04d m%02d d%02d", tm->tm_year, tm->tm_mon, tm->tm_mday);
	printf(" %02d:%02d:%02d\n", tm->tm_hour, tm->tm_min, tm->tm_sec);
#endif

	/* do additional checking for full date specs... */
	if (*dtype == DTK_DATE)
	{
		if ((fmask & DTK_DATE_M) != DTK_DATE_M)
			return ((fmask & DTK_TIME_M) == DTK_TIME_M) ? 1 : -1;

		/*
		 * check for valid day of month, now that we know for sure the
		 * month and year...
		 */
		if ((tm->tm_mday < 1)
		 || (tm->tm_mday > day_tab[isleap(tm->tm_year)][tm->tm_mon - 1]))
			return -1;

		/* timezone not specified? then find local timezone if possible */
		if (((fmask & DTK_DATE_M) == DTK_DATE_M)
			&& (tzp != NULL) && (!(fmask & DTK_M(TZ))))
		{

			/*
			 * daylight savings time modifier but no standard timezone?
			 * then error
			 */
			if (fmask & DTK_M(DTZMOD))
				return -1;

			if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
			{
#ifdef USE_POSIX_TIME
				tm->tm_year -= 1900;
				tm->tm_mon -= 1;
				tm->tm_isdst = -1;
				mktime(tm);
				tm->tm_year += 1900;
				tm->tm_mon += 1;

#if defined(HAVE_TM_ZONE)
				*tzp = -(tm->tm_gmtoff);		/* tm_gmtoff is
												 * Sun/DEC-ism */
#elif defined(HAVE_INT_TIMEZONE)
#ifdef __CYGWIN__
				*tzp = ((tm->tm_isdst > 0) ? (_timezone - 3600) : _timezone);
#else
				*tzp = ((tm->tm_isdst > 0) ? (timezone - 3600) : timezone);
#endif
#else
#error USE_POSIX_TIME is defined but neither HAVE_TM_ZONE or HAVE_INT_TIMEZONE are defined
#endif

#else							/* !USE_POSIX_TIME */
				*tzp = CTimeZone;
#endif
			}
			else
			{
				tm->tm_isdst = 0;
				*tzp = 0;
			}
		}
	}

	return 0;
}	/* DecodeDateTime() */


/* DecodeTimeOnly()
 * Interpret parsed string as time fields only.
 */
int
DecodeTimeOnly(char **field, int *ftype, int nf, int *dtype, struct tm * tm, double *fsec)
{
	int			fmask,
				tmask,
				type;
	int			i;
	int			flen,
				val;
	int			is2digits = FALSE;
	int			mer = HR24;

	*dtype = DTK_TIME;
	tm->tm_hour = 0;
	tm->tm_min = 0;
	tm->tm_sec = 0;
	tm->tm_isdst = -1;			/* don't know daylight savings time status
								 * apriori */
	*fsec = 0;

	fmask = DTK_DATE_M;

	for (i = 0; i < nf; i++)
	{
#ifdef DATEDEBUG
		printf("DecodeTimeOnly- field[%d] is %s (type %d)\n", i, field[i], ftype[i]);
#endif
		switch (ftype[i])
		{
			case DTK_TIME:
				if (DecodeTime(field[i], fmask, &tmask, tm, fsec) != 0)
					return -1;
				break;

			case DTK_NUMBER:
				flen = strlen(field[i]);

				if (DecodeNumberField(flen, field[i], fmask, &tmask, tm, fsec, &is2digits) != 0)
					return -1;
				break;

			case DTK_STRING:
			case DTK_SPECIAL:
				type = DecodeSpecial(i, field[i], &val);
#ifdef DATEDEBUG
				printf("DecodeTimeOnly- special field[%d] %s type=%d value=%d\n", i, field[i], type, val);
#endif
				if (type == IGNORE)
					continue;

				tmask = DTK_M(type);
				switch (type)
				{
					case RESERV:
#ifdef DATEDEBUG
						printf("DecodeTimeOnly- RESERV field %s value is %d\n", field[i], val);
#endif
						switch (val)
						{
							case DTK_NOW:
								tmask = DTK_TIME_M;
								*dtype = DTK_TIME;
								GetCurrentTime(tm);
								break;

							case DTK_ZULU:
								tmask = (DTK_TIME_M | DTK_M(TZ));
								*dtype = DTK_TIME;
								tm->tm_hour = 0;
								tm->tm_min = 0;
								tm->tm_sec = 0;
								tm->tm_isdst = 0;
								break;

							default:
								return -1;
						}

						break;

					case IGNORE:
						break;

					case AMPM:
						mer = val;
						break;

					default:
						return -1;
				}
				break;

			default:
				return -1;
		}

		if (tmask & fmask)
			return -1;
		fmask |= tmask;

#ifdef DATEDEBUG
		printf("DecodeTimeOnly- field[%d] %s value is %d\n", i, field[i], val);
#endif
	}

#ifdef DATEDEBUG
	printf("DecodeTimeOnly- mask %08x (%08x)", fmask, DTK_TIME_M);
	printf(" %02d:%02d:%02d (%f)\n", tm->tm_hour, tm->tm_min, tm->tm_sec, *fsec);
#endif

	if ((mer != HR24) && (tm->tm_hour > 12))
		return -1;
	if ((mer == AM) && (tm->tm_hour == 12))
		tm->tm_hour = 0;
	else if ((mer == PM) && (tm->tm_hour != 12))
		tm->tm_hour += 12;

	if (((tm->tm_hour < 0) || (tm->tm_hour > 23))
		|| ((tm->tm_min < 0) || (tm->tm_min > 59))
		|| ((tm->tm_sec < 0) || ((tm->tm_sec + *fsec) >= 60)))
		return -1;

	if ((fmask & DTK_TIME_M) != DTK_TIME_M)
		return -1;

	return 0;
}	/* DecodeTimeOnly() */


/* DecodeDate()
 * Decode date string which includes delimiters.
 * Insist on a complete set of fields.
 */
static int
DecodeDate(char *str, int fmask, int *tmask, struct tm * tm)
{
	double		fsec;

	int			nf = 0;
	int			i,
				len;
	int			bc = FALSE;
	int			is2digits = FALSE;
	int			type,
				val,
				dmask = 0;
	char	   *field[MAXDATEFIELDS];

	/* parse this string... */
	while ((*str != '\0') && (nf < MAXDATEFIELDS))
	{
		/* skip field separators */
		while (!isalnum(*str))
			str++;

		field[nf] = str;
		if (isdigit(*str))
		{
			while (isdigit(*str))
				str++;
		}
		else if (isalpha(*str))
		{
			while (isalpha(*str))
				str++;
		}

		if (*str != '\0')
			*str++ = '\0';
		nf++;
	}

#if 0
	/* don't allow too many fields */
	if (nf > 3)
		return -1;
#endif

	*tmask = 0;

	/* look first for text fields, since that will be unambiguous month */
	for (i = 0; i < nf; i++)
	{
		if (isalpha(*field[i]))
		{
			type = DecodeSpecial(i, field[i], &val);
			if (type == IGNORE)
				continue;

			dmask = DTK_M(type);
			switch (type)
			{
				case MONTH:
#ifdef DATEDEBUG
					printf("DecodeDate- month field %s value is %d\n", field[i], val);
#endif
					tm->tm_mon = val;
					break;

				case ADBC:
					bc = (val == BC);
					break;

				default:
#ifdef DATEDEBUG
					printf("DecodeDate- illegal field %s value is %d\n", field[i], val);
#endif
					return -1;
			}
			if (fmask & dmask)
				return -1;

			fmask |= dmask;
			*tmask |= dmask;

			/* mark this field as being completed */
			field[i] = NULL;
		}
	}

	/* now pick up remaining numeric fields */
	for (i = 0; i < nf; i++)
	{
		if (field[i] == NULL)
			continue;

		if ((len = strlen(field[i])) <= 0)
			return -1;

		if (DecodeNumber(len, field[i], fmask, &dmask, tm, &fsec, &is2digits) != 0)
			return -1;

		if (fmask & dmask)
			return -1;

		fmask |= dmask;
		*tmask |= dmask;
	}

	if ((fmask & ~(DTK_M(DOY) | DTK_M(TZ))) != DTK_DATE_M)
		return -1;

	/* there is no year zero in AD/BC notation; i.e. "1 BC" == year 0 */
	if (bc)
	{
		if (tm->tm_year > 0)
			tm->tm_year = -(tm->tm_year - 1);
		else
			elog(ERROR, "Inconsistant use of year %04d and 'BC'", tm->tm_year);
	}
	else if (is2digits)
	{
		if (tm->tm_year < 70)
			tm->tm_year += 2000;
		else if (tm->tm_year < 100)
			tm->tm_year += 1900;
	}

	return 0;
}	/* DecodeDate() */


/* DecodeTime()
 * Decode time string which includes delimiters.
 * Only check the lower limit on hours, since this same code
 *	can be used to represent time spans.
 */
static int
DecodeTime(char *str, int fmask, int *tmask, struct tm * tm, double *fsec)
{
	char	   *cp;

	*tmask = DTK_TIME_M;

	tm->tm_hour = strtol(str, &cp, 10);
	if (*cp != ':')
		return -1;
	str = cp + 1;
	tm->tm_min = strtol(str, &cp, 10);
	if (*cp == '\0')
	{
		tm->tm_sec = 0;
		*fsec = 0;

	}
	else if (*cp != ':')
	{
		return -1;

	}
	else
	{
		str = cp + 1;
		tm->tm_sec = strtol(str, &cp, 10);
		if (*cp == '\0')
			*fsec = 0;
		else if (*cp == '.')
		{
			str = cp;
			*fsec = strtod(str, &cp);
			if (cp == str)
				return -1;
		}
		else
			return -1;
	}

	/* do a sanity check */
	if ((tm->tm_hour < 0)
		|| (tm->tm_min < 0) || (tm->tm_min > 59)
		|| (tm->tm_sec < 0) || (tm->tm_sec > 59))
		return -1;

	return 0;
}	/* DecodeTime() */


/* DecodeNumber()
 * Interpret numeric field as a date value in context.
 */
static int
DecodeNumber(int flen, char *str, int fmask,
			 int *tmask, struct tm * tm, double *fsec, int *is2digits)
{
	int			val;
	char	   *cp;

	*tmask = 0;

	val = strtol(str, &cp, 10);
	if (cp == str)
		return -1;
	if (*cp == '.')
	{
		*fsec = strtod(cp, &cp);
		if (*cp != '\0')
			return -1;
	}

#ifdef DATEDEBUG
	printf("DecodeNumber- %s is %d fmask=%08x tmask=%08x\n", str, val, fmask, *tmask);
#endif

	/* Special case day of year? */
	if ((flen == 3) && (fmask & DTK_M(YEAR))
		&& ((val >= 1) && (val <= 366)))
	{
		*tmask = (DTK_M(DOY) | DTK_M(MONTH) | DTK_M(DAY));
		tm->tm_yday = val;
		j2date((date2j(tm->tm_year, 1, 1) + tm->tm_yday - 1),
			   &tm->tm_year, &tm->tm_mon, &tm->tm_mday);

	}

	/*
	 * Enough digits to be unequivocal year? Used to test for 4 digits or
	 * more, but we now test first for a three-digit doy so anything
	 * bigger than two digits had better be an explicit year. - thomas
	 * 1999-01-09
	 */
	else if (flen > 2)
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- match %d (%s) as year\n", val, str);
#endif
		*tmask = DTK_M(YEAR);

		/* already have a year? then see if we can substitute... */
		if ((fmask & DTK_M(YEAR)) && (!(fmask & DTK_M(DAY)))
			&& ((tm->tm_year >= 1) && (tm->tm_year <= 31)))
		{
			tm->tm_mday = tm->tm_year;
			*tmask = DTK_M(DAY);
#ifdef DATEDEBUG
			printf("DecodeNumber- misidentified year previously; assign as day %d\n", tm->tm_mday);
#endif
		}

		tm->tm_year = val;

	}
	/* already have year? then could be month */
	else if ((fmask & DTK_M(YEAR)) && (!(fmask & DTK_M(MONTH)))
			 && ((val >= 1) && (val <= 12)))
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- match %d (%s) as month\n", val, str);
#endif
		*tmask = DTK_M(MONTH);
		tm->tm_mon = val;

		/* no year and EuroDates enabled? then could be day */
	}
	else if ((EuroDates || (fmask & DTK_M(MONTH)))
			 && (!(fmask & DTK_M(YEAR)) && !(fmask & DTK_M(DAY)))
			 && ((val >= 1) && (val <= 31)))
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- match %d (%s) as day\n", val, str);
#endif
		*tmask = DTK_M(DAY);
		tm->tm_mday = val;

	}
	else if ((!(fmask & DTK_M(MONTH)))
			 && ((val >= 1) && (val <= 12)))
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- (2) match %d (%s) as month\n", val, str);
#endif
		*tmask = DTK_M(MONTH);
		tm->tm_mon = val;

	}
	else if ((!(fmask & DTK_M(DAY)))
			 && ((val >= 1) && (val <= 31)))
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- (2) match %d (%s) as day\n", val, str);
#endif
		*tmask = DTK_M(DAY);
		tm->tm_mday = val;

	}
	else if (!(fmask & DTK_M(YEAR)))
	{
#ifdef DATEDEBUG
		printf("DecodeNumber- (2) match %d (%s) as year\n", val, str);
#endif
		*tmask = DTK_M(YEAR);
		tm->tm_year = val;

		/* adjust ONLY if exactly two digits... */
		*is2digits = (flen == 2);

	}
	else
		return -1;

	return 0;
}	/* DecodeNumber() */


/* DecodeNumberField()
 * Interpret numeric string as a concatenated date field.
 */
static int
DecodeNumberField(int len, char *str, int fmask,
				int *tmask, struct tm * tm, double *fsec, int *is2digits)
{
	char	   *cp;

	/* yyyymmdd? */
	if (len == 8)
	{
#ifdef DATEDEBUG
		printf("DecodeNumberField- %s is 8 character date fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif

		*tmask = DTK_DATE_M;

		tm->tm_mday = atoi(str + 6);
		*(str + 6) = '\0';
		tm->tm_mon = atoi(str + 4);
		*(str + 4) = '\0';
		tm->tm_year = atoi(str + 0);

		/* yymmdd or hhmmss? */
	}
	else if (len == 6)
	{
#ifdef DATEDEBUG
		printf("DecodeNumberField- %s is 6 characters fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif
		if (fmask & DTK_DATE_M)
		{
#ifdef DATEDEBUG
			printf("DecodeNumberField- %s is time field fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif
			*tmask = DTK_TIME_M;
			tm->tm_sec = atoi(str + 4);
			*(str + 4) = '\0';
			tm->tm_min = atoi(str + 2);
			*(str + 2) = '\0';
			tm->tm_hour = atoi(str + 0);

		}
		else
		{
#ifdef DATEDEBUG
			printf("DecodeNumberField- %s is date field fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif
			*tmask = DTK_DATE_M;
			tm->tm_mday = atoi(str + 4);
			*(str + 4) = '\0';
			tm->tm_mon = atoi(str + 2);
			*(str + 2) = '\0';
			tm->tm_year = atoi(str + 0);
			*is2digits = TRUE;
		}

	}
	else if ((len == 5) && !(fmask & DTK_DATE_M))
	{
#ifdef DATEDEBUG
		printf("DecodeNumberField- %s is 5 characters fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif
		*tmask = DTK_DATE_M;
		tm->tm_mday = atoi(str + 2);
		*(str + 2) = '\0';
		tm->tm_mon = 1;
		tm->tm_year = atoi(str + 0);
		*is2digits = TRUE;
	}
	else if (strchr(str, '.') != NULL)
	{
#ifdef DATEDEBUG
		printf("DecodeNumberField- %s is time field fmask=%08x tmask=%08x\n", str, fmask, *tmask);
#endif
		*tmask = DTK_TIME_M;
		tm->tm_sec = strtod((str + 4), &cp);
		if (cp == (str + 4))
			return -1;
		if (*cp == '.')
			*fsec = strtod(cp, NULL);
		*(str + 4) = '\0';
		tm->tm_min = strtod((str + 2), &cp);
		*(str + 2) = '\0';
		tm->tm_hour = strtod((str + 0), &cp);

	}
	else
		return -1;

	return 0;
}	/* DecodeNumberField() */


/* DecodeTimezone()
 * Interpret string as a numeric timezone.
 */
static int
DecodeTimezone(char *str, int *tzp)
{
	int			tz;
	int			hr,
				min;
	char	   *cp;
	int			len;

	/* assume leading character is "+" or "-" */
	hr = strtol((str + 1), &cp, 10);

	/* explicit delimiter? */
	if (*cp == ':')
	{
		min = strtol((cp + 1), &cp, 10);

		/* otherwise, might have run things together... */
	}
	else if ((*cp == '\0') && ((len = strlen(str)) > 3))
	{
		min = strtol((str + len - 2), &cp, 10);
		*(str + len - 2) = '\0';
		hr = strtol((str + 1), &cp, 10);

	}
	else
		min = 0;

	tz = (hr * 60 + min) * 60;
	if (*str == '-')
		tz = -tz;

	*tzp = -tz;
	return *cp != '\0';
}	/* DecodeTimezone() */


/* DecodeSpecial()
 * Decode text string using lookup table.
 * Implement a cache lookup since it is likely that dates
 *	will be related in format.
 */
static int
DecodeSpecial(int field, char *lowtoken, int *val)
{
	int			type;
	datetkn    *tp;

#if USE_DATE_CACHE
	if ((datecache[field] != NULL)
		&& (strncmp(lowtoken, datecache[field]->token, TOKMAXLEN) == 0))
		tp = datecache[field];
	else
	{
#endif
		tp = datebsearch(lowtoken, datetktbl, szdatetktbl);
#if USE_DATE_CACHE
	}
	datecache[field] = tp;
#endif
	if (tp == NULL)
	{
		type = IGNORE;
		*val = 0;
	}
	else
	{
		type = tp->type;
		switch (type)
		{
			case TZ:
			case DTZ:
			case DTZMOD:
				*val = FROMVAL(tp);
				break;

			default:
				*val = tp->value;
				break;
		}
	}

	return type;
}	/* DecodeSpecial() */


/* DecodeDateDelta()
 * Interpret previously parsed fields for general time interval.
 * Return 0 if decoded and -1 if problems.
 *
 * Allow "date" field DTK_DATE since this could be just
 *	an unsigned floating point number. - thomas 1997-11-16
 *
 * Allow ISO-style time span, with implicit units on number of days
 *	preceeding an hh:mm:ss field. - thomas 1998-04-30
 */
int
DecodeDateDelta(char **field, int *ftype, int nf, int *dtype, struct tm * tm, double *fsec)
{
	int			is_before = FALSE;

	char	   *cp;
	int			fmask = 0,
				tmask,
				type;
	int			i;
	int			flen,
				val;
	double		fval;
	double		sec;

	*dtype = DTK_DELTA;

	type = DTK_SECOND;
	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;

	/* read through list backwards to pick up units before values */
	for (i = nf - 1; i >= 0; i--)
	{
#ifdef DATEDEBUG
		printf("DecodeDateDelta- field[%d] is %s (type %d)\n", i, field[i], ftype[i]);
#endif
		switch (ftype[i])
		{
			case DTK_TIME:
				if (DecodeTime(field[i], fmask, &tmask, tm, fsec) != 0)
					return -1;
				type = DTK_DAY;
				break;

			case DTK_TZ:

				/*
				 * Timezone is a token with a leading sign character and
				 * otherwise the same as a non-signed numeric field
				 */
			case DTK_DATE:
			case DTK_NUMBER:
				val = strtol(field[i], &cp, 10);
				if (*cp == '.')
				{
					fval = strtod(cp, &cp);
					if (*cp != '\0')
						return -1;

					if (val < 0)
						fval = -(fval);
				}
				else if (*cp == '\0')
					fval = 0;
				else
					return -1;

				flen = strlen(field[i]);
				tmask = 0;		/* DTK_M(type); */

				switch (type)
				{
					case DTK_MICROSEC:
						*fsec += ((val + fval) * 1e-6);
						break;

					case DTK_MILLISEC:
						*fsec += ((val + fval) * 1e-3);
						break;

					case DTK_SECOND:
						tm->tm_sec += val;
						*fsec += fval;
						tmask = DTK_M(SECOND);
						break;

					case DTK_MINUTE:
						tm->tm_min += val;
						if (fval != 0)
							tm->tm_sec += (fval * 60);
						tmask = DTK_M(MINUTE);
						break;

					case DTK_HOUR:
						tm->tm_hour += val;
						if (fval != 0)
							tm->tm_sec += (fval * 3600);
						tmask = DTK_M(HOUR);
						break;

					case DTK_DAY:
						tm->tm_mday += val;
						if (fval != 0)
							tm->tm_sec += (fval * 86400);
						tmask = ((fmask & DTK_M(DAY)) ? 0 : DTK_M(DAY));
						break;

					case DTK_WEEK:
						tm->tm_mday += val * 7;
						if (fval != 0)
							tm->tm_sec += (fval * (7 * 86400));
						tmask = ((fmask & DTK_M(DAY)) ? 0 : DTK_M(DAY));
						break;

					case DTK_MONTH:
						tm->tm_mon += val;
						if (fval != 0)
							tm->tm_sec += (fval * (30 * 86400));
						tmask = DTK_M(MONTH);
						break;

					case DTK_YEAR:
						tm->tm_year += val;
						if (fval != 0)
							tm->tm_mon += (fval * 12);
						tmask = ((fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR));
						break;

					case DTK_DECADE:
						tm->tm_year += val * 10;
						if (fval != 0)
							tm->tm_mon += (fval * 120);
						tmask = ((fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR));
						break;

					case DTK_CENTURY:
						tm->tm_year += val * 100;
						if (fval != 0)
							tm->tm_mon += (fval * 1200);
						tmask = ((fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR));
						break;

					case DTK_MILLENIUM:
						tm->tm_year += val * 1000;
						if (fval != 0)
							tm->tm_mon += (fval * 12000);
						tmask = ((fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR));
						break;

					default:
						return -1;
				}
				break;

			case DTK_STRING:
			case DTK_SPECIAL:
				type = DecodeUnits(i, field[i], &val);
#ifdef DATEDEBUG
				printf("DecodeDateDelta- special field[%d] %s type=%d value=%d\n", i, field[i], type, val);
#endif
				if (type == IGNORE)
					continue;

				tmask = 0;		/* DTK_M(type); */
				switch (type)
				{
					case UNITS:
#ifdef DATEDEBUG
						printf("DecodeDateDelta- UNITS field %s value is %d\n", field[i], val);
#endif
						type = val;
						break;

					case AGO:
						is_before = TRUE;
						type = val;
						break;

					case RESERV:
						tmask = (DTK_DATE_M || DTK_TIME_M);
						*dtype = val;
						break;

					default:
						return -1;
				}
				break;

			default:
				return -1;
		}

#ifdef DATEDEBUG
		printf("DecodeDateDelta- (%08x/%08x) field[%d] %s value is %d\n",
			   fmask, tmask, i, field[i], val);
#endif

		if (tmask & fmask)
			return -1;
		fmask |= tmask;
	}

	if (*fsec != 0)
	{
		TMODULO(*fsec, sec, 1e0);
		tm->tm_sec += sec;
	}

	if (is_before)
	{
		*fsec = -(*fsec);
		tm->tm_sec = -(tm->tm_sec);
		tm->tm_min = -(tm->tm_min);
		tm->tm_hour = -(tm->tm_hour);
		tm->tm_mday = -(tm->tm_mday);
		tm->tm_mon = -(tm->tm_mon);
		tm->tm_year = -(tm->tm_year);
	}

#ifdef DATEDEBUG
	printf("DecodeDateDelta- mask %08x (%08x)", fmask, DTK_DATE_M);
	printf(" set y%04d m%02d d%02d", tm->tm_year, tm->tm_mon, tm->tm_mday);
	printf(" %02d:%02d:%02d\n", tm->tm_hour, tm->tm_min, tm->tm_sec);
#endif

	/* ensure that at least one time field has been found */
	return (fmask != 0) ? 0 : -1;
}	/* DecodeDateDelta() */


/* DecodeUnits()
 * Decode text string using lookup table.
 * This routine supports time interval decoding.
 */
static int
DecodeUnits(int field, char *lowtoken, int *val)
{
	int			type;
	datetkn    *tp;

#if USE_DATE_CACHE
	if ((deltacache[field] != NULL)
		&& (strncmp(lowtoken, deltacache[field]->token, TOKMAXLEN) == 0))
		tp = deltacache[field];
	else
	{
#endif
		tp = datebsearch(lowtoken, deltatktbl, szdeltatktbl);
#if USE_DATE_CACHE
	}
	deltacache[field] = tp;
#endif
	if (tp == NULL)
	{
		type = IGNORE;
		*val = 0;
	}
	else
	{
		type = tp->type;
		if ((type == TZ) || (type == DTZ))
			*val = FROMVAL(tp);
		else
			*val = tp->value;
	}

	return type;
}	/* DecodeUnits() */


/* datebsearch()
 * Binary search -- from Knuth (6.2.1) Algorithm B.  Special case like this
 * is WAY faster than the generic bsearch().
 */
static datetkn *
datebsearch(char *key, datetkn *base, unsigned int nel)
{
	datetkn    *last = base + nel - 1,
			   *position;
	int			result;

	while (last >= base)
	{
		position = base + ((last - base) >> 1);
		result = key[0] - position->token[0];
		if (result == 0)
		{
			result = strncmp(key, position->token, TOKMAXLEN);
			if (result == 0)
				return position;
		}
		if (result < 0)
			last = position - 1;
		else
			base = position + 1;
	}
	return NULL;
}


/* EncodeSpecialDateTime()
 * Convert reserved datetime data type to string.
 */
static int
EncodeSpecialDateTime(DateTime dt, char *str)
{
	if (DATETIME_IS_RESERVED(dt))
	{
		if (DATETIME_IS_INVALID(dt))
		{
			strcpy(str, INVALID);

		}
		else if (DATETIME_IS_NOBEGIN(dt))
		{
			strcpy(str, EARLY);

		}
		else if (DATETIME_IS_NOEND(dt))
		{
			strcpy(str, LATE);

		}
		else if (DATETIME_IS_CURRENT(dt))
		{
			strcpy(str, DCURRENT);

		}
		else if (DATETIME_IS_EPOCH(dt))
		{
			strcpy(str, EPOCH);

		}
		else
		{
#ifdef DATEDEBUG
			printf("EncodeSpecialDateTime- unrecognized date\n");
#endif
			strcpy(str, INVALID);
		}
		return TRUE;
	}

	return FALSE;
}	/* EncodeSpecialDateTime() */


/* EncodeDateOnly()
 * Encode date as local time.
 */
int
EncodeDateOnly(struct tm * tm, int style, char *str)
{
	if ((tm->tm_mon < 1) || (tm->tm_mon > 12))
		return -1;

	switch (style)
	{
			/* compatible with ISO date formats */
		case USE_ISO_DATES:
			if (tm->tm_year > 0)
				sprintf(str, "%04d-%02d-%02d",
						tm->tm_year, tm->tm_mon, tm->tm_mday);
			else
				sprintf(str, "%04d-%02d-%02d %s",
					  -(tm->tm_year - 1), tm->tm_mon, tm->tm_mday, "BC");
			break;

			/* compatible with Oracle/Ingres date formats */
		case USE_SQL_DATES:
			if (EuroDates)
				sprintf(str, "%02d/%02d", tm->tm_mday, tm->tm_mon);
			else
				sprintf(str, "%02d/%02d", tm->tm_mon, tm->tm_mday);
			if (tm->tm_year > 0)
				sprintf((str + 5), "/%04d", tm->tm_year);
			else
				sprintf((str + 5), "/%04d %s", -(tm->tm_year - 1), "BC");
			break;

			/* German-style date format */
		case USE_GERMAN_DATES:
			sprintf(str, "%02d.%02d", tm->tm_mday, tm->tm_mon);
			if (tm->tm_year > 0)
				sprintf((str + 5), ".%04d", tm->tm_year);
			else
				sprintf((str + 5), ".%04d %s", -(tm->tm_year - 1), "BC");
			break;

			/* traditional date-only style for Postgres */
		case USE_POSTGRES_DATES:
		default:
			if (EuroDates)
				sprintf(str, "%02d-%02d", tm->tm_mday, tm->tm_mon);
			else
				sprintf(str, "%02d-%02d", tm->tm_mon, tm->tm_mday);
			if (tm->tm_year > 0)
				sprintf((str + 5), "-%04d", tm->tm_year);
			else
				sprintf((str + 5), "-%04d %s", -(tm->tm_year - 1), "BC");
			break;
	}

#ifdef DATEDEBUG
	printf("EncodeDateOnly- date result is %s\n", str);
#endif

	return TRUE;
}	/* EncodeDateOnly() */


/* EncodeTimeOnly()
 * Encode time fields only.
 */
int
EncodeTimeOnly(struct tm * tm, double fsec, int style, char *str)
{
	double		sec;

	if ((tm->tm_hour < 0) || (tm->tm_hour > 24))
		return -1;

	sec = (tm->tm_sec + fsec);

	sprintf(str, "%02d:%02d:", tm->tm_hour, tm->tm_min);
	sprintf((str + 6), ((fsec != 0) ? "%05.2f" : "%02.0f"), sec);

#ifdef DATEDEBUG
	printf("EncodeTimeOnly- time result is %s\n", str);
#endif

	return TRUE;
}	/* EncodeTimeOnly() */


/* EncodeDateTime()
 * Encode date and time interpreted as local time.
 * Support several date styles:
 *	Postgres - day mon hh:mm:ss yyyy tz
 *	SQL - mm/dd/yyyy hh:mm:ss.ss tz
 *	ISO - yyyy-mm-dd hh:mm:ss+/-tz
 *	German - dd.mm/yyyy hh:mm:ss tz
 * Variants (affects order of month and day for Postgres and SQL styles):
 *	US - mm/dd/yyyy
 *	European - dd/mm/yyyy
 */
int
EncodeDateTime(struct tm * tm, double fsec, int *tzp, char **tzn, int style, char *str)
{
	int			day,
				hour,
				min;
	double		sec;

	if ((tm->tm_mon < 1) || (tm->tm_mon > 12))
		return -1;

	sec = (tm->tm_sec + fsec);

#ifdef DATEDEBUG
#ifdef USE_POSIX_TIME
#if defined(HAVE_TM_ZONE)
	printf("EncodeDateTime- timezone is %s (%s); offset is %ld (%d); daylight is %d (%d)\n",
		   *tzn, tm->tm_zone, (-tm->tm_gmtoff), CTimeZone, tm->tm_isdst, CDayLight);
#elif defined(HAVE_INT_TIMEZONE)
	printf("EncodeDateTime- timezone is %s (%s); offset is %d (%d); daylight is %d (%d)\n",
		   *tzn, tzname[0], *tzp, CTimeZone, tm->tm_isdst, CDayLight);
#else
#error USE_POSIX_TIME is defined but neither HAVE_TM_ZONE or HAVE_INT_TIMEZONE are defined
#endif
#else
	printf("EncodeDateTime- timezone is %s (%s); offset is %d; daylight is %d\n",
		   *tzn, CTZName, CTimeZone, CDayLight);
#endif
#endif

	switch (style)
	{
			/* compatible with ISO date formats */

		case USE_ISO_DATES:
			if (tm->tm_year > 0)
			{
				sprintf(str, "%04d-%02d-%02d %02d:%02d:",
						tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min);
				sprintf((str + 17), ((fsec != 0) ? "%05.2f" : "%02.0f"), sec);

				if ((*tzn != NULL) && (tm->tm_isdst >= 0))
				{
					if (tzp != NULL)
					{
						hour = -(*tzp / 3600);
						min = ((abs(*tzp) / 60) % 60);
					}
					else
					{
						hour = 0;
						min = 0;
					}
					sprintf((str + strlen(str)), ((min != 0) ? "%+03d:%02d" : "%+03d"), hour, min);
				}

			}
			else
			{
				if (tm->tm_hour || tm->tm_min)
					sprintf(str, "%04d-%02d-%02d %02d:%02d %s",
							-(tm->tm_year - 1), tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, "BC");
				else
					sprintf(str, "%04d-%02d-%02d %s",
					  -(tm->tm_year - 1), tm->tm_mon, tm->tm_mday, "BC");
			}
			break;

			/* compatible with Oracle/Ingres date formats */
		case USE_SQL_DATES:
			if (EuroDates)
				sprintf(str, "%02d/%02d", tm->tm_mday, tm->tm_mon);
			else
				sprintf(str, "%02d/%02d", tm->tm_mon, tm->tm_mday);

			if (tm->tm_year > 0)
			{
				sprintf((str + 5), "/%04d %02d:%02d:%05.2f",
						tm->tm_year, tm->tm_hour, tm->tm_min, sec);

				if ((*tzn != NULL) && (tm->tm_isdst >= 0))
				{
					strcpy((str + 22), " ");
					strcpy((str + 23), *tzn);
				}

			}
			else
				sprintf((str + 5), "/%04d %02d:%02d %s",
					  -(tm->tm_year - 1), tm->tm_hour, tm->tm_min, "BC");
			break;

			/* German variant on European style */
		case USE_GERMAN_DATES:
			sprintf(str, "%02d.%02d", tm->tm_mday, tm->tm_mon);
			if (tm->tm_year > 0)
			{
				sprintf((str + 5), ".%04d %02d:%02d:%05.2f",
						tm->tm_year, tm->tm_hour, tm->tm_min, sec);

				if ((*tzn != NULL) && (tm->tm_isdst >= 0))
				{
					strcpy((str + 22), " ");
					strcpy((str + 23), *tzn);
				}

			}
			else
				sprintf((str + 5), ".%04d %02d:%02d %s",
					  -(tm->tm_year - 1), tm->tm_hour, tm->tm_min, "BC");
			break;

			/* backward-compatible with traditional Postgres abstime dates */
		case USE_POSTGRES_DATES:
		default:
			day = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday);
#ifdef DATEDEBUG
			printf("EncodeDateTime- day is %d\n", day);
#endif
			tm->tm_wday = j2day(day);

			strncpy(str, days[tm->tm_wday], 3);
			strcpy((str + 3), " ");

			if (EuroDates)
				sprintf((str + 4), "%02d %3s", tm->tm_mday, months[tm->tm_mon - 1]);
			else
				sprintf((str + 4), "%3s %02d", months[tm->tm_mon - 1], tm->tm_mday);

			if (tm->tm_year > 0)
			{
				sprintf((str + 10), " %02d:%02d", tm->tm_hour, tm->tm_min);
				if (fsec != 0)
				{
					sprintf((str + 16), ":%05.2f %04d", sec, tm->tm_year);
					if ((*tzn != NULL) && (tm->tm_isdst >= 0))
					{
						strcpy((str + 27), " ");
						strcpy((str + 28), *tzn);
					}
				}
				else
				{
					sprintf((str + 16), ":%02.0f %04d", sec, tm->tm_year);
					if ((*tzn != NULL) && (tm->tm_isdst >= 0))
					{
						strcpy((str + 24), " ");
						strcpy((str + 25), *tzn);
					}
				}

			}
			else
			{
				sprintf((str + 10), " %02d:%02d %04d %s",
					  tm->tm_hour, tm->tm_min, -(tm->tm_year - 1), "BC");
			}
			break;
	}

#ifdef DATEDEBUG
	printf("EncodeDateTime- date result is %s\n", str);
#endif

	return TRUE;
}	/* EncodeDateTime() */


/* EncodeTimeSpan()
 * Interpret time structure as a delta time and convert to string.
 *
 * Support "traditional Postgres" and ISO-8601 styles.
 * Actually, afaik ISO does not address time interval formatting,
 *	but this looks similar to the spec for absolute date/time.
 * - thomas 1998-04-30
 */
int
EncodeTimeSpan(struct tm * tm, double fsec, int style, char *str)
{
	int			is_before = FALSE;
	int			is_nonzero = FALSE;
	char	   *cp = str;

	switch (style)
	{
			/* compatible with ISO date formats */
		case USE_ISO_DATES:
			break;

		default:
			strcpy(cp, "@ ");
			cp += strlen(cp);
			break;
	}

	if (tm->tm_year != 0)
	{
		is_before |= (tm->tm_year < 0);
		sprintf(cp, "%d year%s",
				abs(tm->tm_year), ((abs(tm->tm_year) != 1) ? "s" : ""));
		cp += strlen(cp);
		is_nonzero = TRUE;
	}

	if (tm->tm_mon != 0)
	{
		is_before |= (tm->tm_mon < 0);
		sprintf(cp, "%s%d mon%s", (is_nonzero ? " " : ""),
				abs(tm->tm_mon), ((abs(tm->tm_mon) != 1) ? "s" : ""));
		cp += strlen(cp);
		is_nonzero = TRUE;
	}

	switch (style)
	{
			/* compatible with ISO date formats */
		case USE_ISO_DATES:
			if (tm->tm_mday != 0)
			{
				is_before |= (tm->tm_mday < 0);
				sprintf(cp, "%s%d", (is_nonzero ? " " : ""), abs(tm->tm_mday));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}
			is_before |= ((tm->tm_hour < 0) || (tm->tm_min < 0));
			sprintf(cp, "%s%02d:%02d", (is_nonzero ? " " : ""),
					abs(tm->tm_hour), abs(tm->tm_min));
			cp += strlen(cp);
			if ((tm->tm_hour != 0) || (tm->tm_min != 0))
				is_nonzero = TRUE;

			/* fractional seconds? */
			if (fsec != 0)
			{
				fsec += tm->tm_sec;
				is_before |= (fsec < 0);
				sprintf(cp, ":%05.2f", fabs(fsec));
				cp += strlen(cp);
				is_nonzero = TRUE;

				/* otherwise, integer seconds only? */
			}
			else if (tm->tm_sec != 0)
			{
				is_before |= (tm->tm_sec < 0);
				sprintf(cp, ":%02d", abs(tm->tm_sec));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}
			break;

		case USE_POSTGRES_DATES:
		default:
			if (tm->tm_mday != 0)
			{
				is_before |= (tm->tm_mday < 0);
				sprintf(cp, "%s%d day%s", (is_nonzero ? " " : ""),
				 abs(tm->tm_mday), ((abs(tm->tm_mday) != 1) ? "s" : ""));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}
			if (tm->tm_hour != 0)
			{
				is_before |= (tm->tm_hour < 0);
				sprintf(cp, "%s%d hour%s", (is_nonzero ? " " : ""),
				 abs(tm->tm_hour), ((abs(tm->tm_hour) != 1) ? "s" : ""));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}

			if (tm->tm_min != 0)
			{
				is_before |= (tm->tm_min < 0);
				sprintf(cp, "%s%d min%s", (is_nonzero ? " " : ""),
				   abs(tm->tm_min), ((abs(tm->tm_min) != 1) ? "s" : ""));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}

			/* fractional seconds? */
			if (fsec != 0)
			{
				fsec += tm->tm_sec;
				is_before |= (fsec < 0);
				sprintf(cp, "%s%.2f secs", (is_nonzero ? " " : ""), fabs(fsec));
				cp += strlen(cp);
				is_nonzero = TRUE;

				/* otherwise, integer seconds only? */
			}
			else if (tm->tm_sec != 0)
			{
				is_before |= (tm->tm_sec < 0);
				sprintf(cp, "%s%d sec%s", (is_nonzero ? " " : ""),
				   abs(tm->tm_sec), ((abs(tm->tm_sec) != 1) ? "s" : ""));
				cp += strlen(cp);
				is_nonzero = TRUE;
			}
			break;
	}

	/* identically zero? then put in a unitless zero... */
	if (!is_nonzero)
	{
		strcat(cp, "0");
		cp += strlen(cp);
	}

	if (is_before)
	{
		strcat(cp, " ago");
		cp += strlen(cp);
	}

#ifdef DATEDEBUG
	printf("EncodeTimeSpan- result is %s\n", str);
#endif

	return 0;
}	/* EncodeTimeSpan() */


#if defined(linux) && defined(__powerpc__)
int
datetime_is_epoch(double j)
{
	static union
	{
		double		epoch;
		unsigned char c[8];
	}			u;

	u.c[0] = 0x80;				/* sign bit */
	u.c[1] = 0x10;				/* DBL_MIN */

	return j == u.epoch;
}
int
datetime_is_current(double j)
{
	static union
	{
		double		current;
		unsigned char c[8];
	}			u;

	u.c[1] = 0x10;				/* DBL_MIN */

	return j == u.current;
}

#endif
