timestamp.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	 */
	if (attimezone == NULL && HasCTZSet)
	{
		*tzp = CTimeZone;
		tm->tm_isdst = 0;
		tm->tm_gmtoff = CTimeZone;
		tm->tm_zone = NULL;
		if (tzn != NULL)
			*tzn = NULL;
		return 0;
	}

	/*
	 * If the time falls within the range of pg_time_t, use pg_localtime() to
	 * rotate to the local time zone.
	 *
	 * First, convert to an integral timestamp, avoiding possibly
	 * platform-specific roundoff-in-wrong-direction errors, and adjust to
	 * Unix epoch.	Then see if we can convert to pg_time_t without loss. This
	 * coding avoids hardwiring any assumptions about the width of pg_time_t,
	 * so it should behave sanely on machines without int64.
	 */
#ifdef HAVE_INT64_TIMESTAMP
	dt = (dt - *fsec) / USECS_PER_SEC +
		(POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY;
#else
	dt = rint(dt - *fsec +
			  (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);
#endif
	utime = (pg_time_t) dt;
	if ((Timestamp) utime == dt)
	{
		struct pg_tm *tx = pg_localtime(&utime,
								  attimezone ? attimezone : global_timezone);

		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;
		tm->tm_sec = tx->tm_sec;
		tm->tm_isdst = tx->tm_isdst;
		tm->tm_gmtoff = tx->tm_gmtoff;
		tm->tm_zone = tx->tm_zone;
		*tzp = -tm->tm_gmtoff;
		if (tzn != NULL)
			*tzn = (char *) tm->tm_zone;
	}
	else
	{
		/*
		 * When out of range of pg_time_t, treat as GMT
		 */
		*tzp = 0;
		/* Mark this as *no* time zone available */
		tm->tm_isdst = -1;
		tm->tm_gmtoff = 0;
		tm->tm_zone = NULL;
		if (tzn != NULL)
			*tzn = NULL;
	}

	return 0;
}


/* tm2timestamp()
 * Convert a tm structure to a timestamp data type.
 * Note that year is _not_ 1900-based, but is an explicit full value.
 * Also, month is one-based, _not_ zero-based.
 *
 * Returns -1 on failure (value out of range).
 */
int
tm2timestamp(struct pg_tm * tm, fsec_t fsec, int *tzp, Timestamp *result)
{
#ifdef HAVE_INT64_TIMESTAMP
	int			date;
	int64		time;
#else
	double		date,
				time;
#endif

	/* 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) - POSTGRES_EPOCH_JDATE;
	time = time2t(tm->tm_hour, tm->tm_min, tm->tm_sec, fsec);

#ifdef HAVE_INT64_TIMESTAMP
	*result = date * USECS_PER_DAY + time;
	/* check for major overflow */
	if ((*result - time) / USECS_PER_DAY != date)
		return -1;
	/* check for just-barely overflow (okay except time-of-day wraps) */
	if ((*result < 0 && date >= 0) ||
		(*result >= 0 && date < 0))
		return -1;
#else
	*result = date * SECS_PER_DAY + time;
#endif
	if (tzp != NULL)
		*result = dt2local(*result, -(*tzp));

	return 0;
}


/* interval2tm()
 * Convert a interval data type to a tm structure.
 */
int
interval2tm(Interval span, struct pg_tm * tm, fsec_t *fsec)
{
#ifdef HAVE_INT64_TIMESTAMP
	int64		time;
	int64		tfrac;
#else
	double		time;
	double		tfrac;
#endif

	tm->tm_year = span.month / MONTHS_PER_YEAR;
	tm->tm_mon = span.month % MONTHS_PER_YEAR;
	tm->tm_mday = span.day;
	time = span.time;

#ifdef HAVE_INT64_TIMESTAMP
	tfrac = time / USECS_PER_HOUR;
	time -= tfrac * USECS_PER_HOUR;
	tm->tm_hour = tfrac;		/* could overflow ... */
	tfrac = time / USECS_PER_MINUTE;
	time -= tfrac * USECS_PER_MINUTE;
	tm->tm_min = tfrac;
	tfrac = time / USECS_PER_SEC;
	*fsec = time - (tfrac * USECS_PER_SEC);
	tm->tm_sec = tfrac;
#else
recalc:
	TMODULO(time, tfrac, (double) SECS_PER_HOUR);
	tm->tm_hour = tfrac;		/* could overflow ... */
	TMODULO(time, tfrac, (double) SECS_PER_MINUTE);
	tm->tm_min = tfrac;
	TMODULO(time, tfrac, 1.0);
	tm->tm_sec = tfrac;
	time = TSROUND(time);
	/* roundoff may need to propagate to higher-order fields */
	if (time >= 1.0)
	{
		time = ceil(span.time);
		goto recalc;
	}
	*fsec = time;
#endif

	return 0;
}

int
tm2interval(struct pg_tm * tm, fsec_t fsec, Interval *span)
{
	span->month = tm->tm_year * MONTHS_PER_YEAR + tm->tm_mon;
	span->day = tm->tm_mday;
#ifdef HAVE_INT64_TIMESTAMP
	span->time = (((((tm->tm_hour * INT64CONST(60)) +
					 tm->tm_min) * INT64CONST(60)) +
				   tm->tm_sec) * USECS_PER_SEC) + fsec;
#else
	span->time = (((tm->tm_hour * (double) MINS_PER_HOUR) +
				   tm->tm_min) * (double) SECS_PER_MINUTE) +
		tm->tm_sec + fsec;
#endif

	return 0;
}

#ifdef HAVE_INT64_TIMESTAMP
static int64
time2t(const int hour, const int min, const int sec, const fsec_t fsec)
{
	return (((((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec) * USECS_PER_SEC) + fsec;
}	/* time2t() */
#else
static double
time2t(const int hour, const int min, const int sec, const fsec_t fsec)
{
	return (((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec;
}	/* time2t() */
#endif

static Timestamp
dt2local(Timestamp dt, int tz)
{
#ifdef HAVE_INT64_TIMESTAMP
	dt -= (tz * USECS_PER_SEC);
#else
	dt -= tz;
#endif
	return dt;
}	/* dt2local() */


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


Datum
timestamp_finite(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);

	PG_RETURN_BOOL(!TIMESTAMP_NOT_FINITE(timestamp));
}

Datum
interval_finite(PG_FUNCTION_ARGS)
{
	PG_RETURN_BOOL(true);
}


/*----------------------------------------------------------
 *	Relational operators for timestamp.
 *---------------------------------------------------------*/

void
GetEpochTime(struct pg_tm * tm)
{
	struct pg_tm *t0;
	pg_time_t	epoch = 0;

	t0 = pg_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;

	tm->tm_year += 1900;
	tm->tm_mon++;
}

Timestamp
SetEpochTimestamp(void)
{
	Timestamp	dt;
	struct pg_tm tt,
			   *tm = &tt;

	GetEpochTime(tm);
	/* we don't bother to test for failure ... */
	tm2timestamp(tm, 0, NULL, &dt);

	return dt;
}	/* SetEpochTimestamp() */

/*
 * We are currently sharing some code between timestamp and timestamptz.
 * The comparison functions are among them. - thomas 2001-09-25
 *
 *		timestamp_relop - is timestamp1 relop timestamp2
 *
 *		collate invalid timestamp at the end
 */
int
timestamp_cmp_internal(Timestamp dt1, Timestamp dt2)
{
#ifdef HAVE_INT64_TIMESTAMP
	return (dt1 < dt2) ? -1 : ((dt1 > dt2) ? 1 : 0);
#else

	/*
	 * When using float representation, we have to be wary of NaNs.
	 *
	 * We consider all NANs to be equal and larger than any non-NAN. This is
	 * somewhat arbitrary; the important thing is to have a consistent sort
	 * order.
	 */
	if (isnan(dt1))
	{
		if (isnan(dt2))
			return 0;			/* NAN = NAN */
		else
			return 1;			/* NAN > non-NAN */
	}
	else if (isnan(dt2))
	{
		return -1;				/* non-NAN < NAN */
	}
	else
	{
		if (dt1 > dt2)
			return 1;
		else if (dt1 < dt2)
			return -1;
		else
			return 0;
	}
#endif
}

Datum
timestamp_eq(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) == 0);
}

Datum
timestamp_ne(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) != 0);
}

Datum
timestamp_lt(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) < 0);
}

Datum
timestamp_gt(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) > 0);
}

Datum
timestamp_le(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) <= 0);
}

Datum
timestamp_ge(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) >= 0);
}

Datum
timestamp_cmp(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);

	PG_RETURN_INT32(timestamp_cmp_internal(dt1, dt2));
}


/*
 * Crosstype comparison functions for timestamp vs timestamptz
 */

Datum
timestamp_eq_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) == 0);
}

Datum
timestamp_ne_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) != 0);
}

Datum
timestamp_lt_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) < 0);
}

Datum
timestamp_gt_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) > 0);
}

Datum
timestamp_le_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) <= 0);
}

Datum
timestamp_ge_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) >= 0);
}

Datum
timestamp_cmp_timestamptz(PG_FUNCTION_ARGS)
{
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	TimestampTz dt1;

	dt1 = timestamp2timestamptz(timestampVal);

	PG_RETURN_INT32(timestamp_cmp_internal(dt1, dt2));
}

Datum
timestamptz_eq_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) == 0);
}

Datum
timestamptz_ne_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) != 0);
}

Datum
timestamptz_lt_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) < 0);
}

Datum
timestamptz_gt_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) > 0);
}

Datum
timestamptz_le_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) <= 0);
}

Datum
timestamptz_ge_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) >= 0);
}

Datum
timestamptz_cmp_timestamp(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	Timestamp	timestampVal = PG_GETARG_TIMESTAMP(1);
	TimestampTz dt2;

	dt2 = timestamp2timestamptz(timestampVal);

	PG_RETURN_INT32(timestamp_cmp_internal(dt1, dt2));
}


/*
 *		interval_relop	- is interval1 relop interval2
 *
 *		collate invalid interval at the end
 */
static int
interval_cmp_internal(Interval *interval1, Interval *interval2)
{
#ifdef HAVE_INT64_TIMESTAMP
	int64		span1,
				span2;