timestamp.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

#else
	double		span1,
				span2;
#endif

	span1 = interval1->time;
	span2 = interval2->time;

#ifdef HAVE_INT64_TIMESTAMP
	span1 += interval1->month * INT64CONST(30) * USECS_PER_DAY;
	span1 += interval1->day * INT64CONST(24) * USECS_PER_HOUR;
	span2 += interval2->month * INT64CONST(30) * USECS_PER_DAY;
	span2 += interval2->day * INT64CONST(24) * USECS_PER_HOUR;
#else
	span1 += interval1->month * ((double) DAYS_PER_MONTH * SECS_PER_DAY);
	span1 += interval1->day * ((double) HOURS_PER_DAY * SECS_PER_HOUR);
	span2 += interval2->month * ((double) DAYS_PER_MONTH * SECS_PER_DAY);
	span2 += interval2->day * ((double) HOURS_PER_DAY * SECS_PER_HOUR);
#endif

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

Datum
interval_eq(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) == 0);
}

Datum
interval_ne(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) != 0);
}

Datum
interval_lt(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) < 0);
}

Datum
interval_gt(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) > 0);
}

Datum
interval_le(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) <= 0);
}

Datum
interval_ge(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) >= 0);
}

Datum
interval_cmp(PG_FUNCTION_ARGS)
{
	Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
	Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

	PG_RETURN_INT32(interval_cmp_internal(interval1, interval2));
}

/*
 * interval, being an unusual size, needs a specialized hash function.
 */
Datum
interval_hash(PG_FUNCTION_ARGS)
{
	Interval   *key = PG_GETARG_INTERVAL_P(0);

	/*
	 * Specify hash length as sizeof(double) + sizeof(int4), not as
	 * sizeof(Interval), so that any garbage pad bytes in the structure won't
	 * be included in the hash!
	 */
	return hash_any((unsigned char *) key,
				  sizeof(key->time) + sizeof(key->day) + sizeof(key->month));
}

/* overlaps_timestamp() --- implements the SQL92 OVERLAPS operator.
 *
 * Algorithm is per SQL92 spec.  This is much harder than you'd think
 * because the spec requires us to deliver a non-null answer in some cases
 * where some of the inputs are null.
 */
Datum
overlaps_timestamp(PG_FUNCTION_ARGS)
{
	/*
	 * The arguments are Timestamps, but we leave them as generic Datums to
	 * avoid unnecessary conversions between value and reference forms --- not
	 * to mention possible dereferences of null pointers.
	 */
	Datum		ts1 = PG_GETARG_DATUM(0);
	Datum		te1 = PG_GETARG_DATUM(1);
	Datum		ts2 = PG_GETARG_DATUM(2);
	Datum		te2 = PG_GETARG_DATUM(3);
	bool		ts1IsNull = PG_ARGISNULL(0);
	bool		te1IsNull = PG_ARGISNULL(1);
	bool		ts2IsNull = PG_ARGISNULL(2);
	bool		te2IsNull = PG_ARGISNULL(3);

#define TIMESTAMP_GT(t1,t2) \
	DatumGetBool(DirectFunctionCall2(timestamp_gt,t1,t2))
#define TIMESTAMP_LT(t1,t2) \
	DatumGetBool(DirectFunctionCall2(timestamp_lt,t1,t2))

	/*
	 * If both endpoints of interval 1 are null, the result is null (unknown).
	 * If just one endpoint is null, take ts1 as the non-null one. Otherwise,
	 * take ts1 as the lesser endpoint.
	 */
	if (ts1IsNull)
	{
		if (te1IsNull)
			PG_RETURN_NULL();
		/* swap null for non-null */
		ts1 = te1;
		te1IsNull = true;
	}
	else if (!te1IsNull)
	{
		if (TIMESTAMP_GT(ts1, te1))
		{
			Datum		tt = ts1;

			ts1 = te1;
			te1 = tt;
		}
	}

	/* Likewise for interval 2. */
	if (ts2IsNull)
	{
		if (te2IsNull)
			PG_RETURN_NULL();
		/* swap null for non-null */
		ts2 = te2;
		te2IsNull = true;
	}
	else if (!te2IsNull)
	{
		if (TIMESTAMP_GT(ts2, te2))
		{
			Datum		tt = ts2;

			ts2 = te2;
			te2 = tt;
		}
	}

	/*
	 * At this point neither ts1 nor ts2 is null, so we can consider three
	 * cases: ts1 > ts2, ts1 < ts2, ts1 = ts2
	 */
	if (TIMESTAMP_GT(ts1, ts2))
	{
		/*
		 * This case is ts1 < te2 OR te1 < te2, which may look redundant but
		 * in the presence of nulls it's not quite completely so.
		 */
		if (te2IsNull)
			PG_RETURN_NULL();
		if (TIMESTAMP_LT(ts1, te2))
			PG_RETURN_BOOL(true);
		if (te1IsNull)
			PG_RETURN_NULL();

		/*
		 * If te1 is not null then we had ts1 <= te1 above, and we just found
		 * ts1 >= te2, hence te1 >= te2.
		 */
		PG_RETURN_BOOL(false);
	}
	else if (TIMESTAMP_LT(ts1, ts2))
	{
		/* This case is ts2 < te1 OR te2 < te1 */
		if (te1IsNull)
			PG_RETURN_NULL();
		if (TIMESTAMP_LT(ts2, te1))
			PG_RETURN_BOOL(true);
		if (te2IsNull)
			PG_RETURN_NULL();

		/*
		 * If te2 is not null then we had ts2 <= te2 above, and we just found
		 * ts2 >= te1, hence te2 >= te1.
		 */
		PG_RETURN_BOOL(false);
	}
	else
	{
		/*
		 * For ts1 = ts2 the spec says te1 <> te2 OR te1 = te2, which is a
		 * rather silly way of saying "true if both are nonnull, else null".
		 */
		if (te1IsNull || te2IsNull)
			PG_RETURN_NULL();
		PG_RETURN_BOOL(true);
	}

#undef TIMESTAMP_GT
#undef TIMESTAMP_LT
}


/*----------------------------------------------------------
 *	"Arithmetic" operators on date/times.
 *---------------------------------------------------------*/

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

	/* use timestamp_cmp_internal to be sure this agrees with comparisons */
	if (timestamp_cmp_internal(dt1, dt2) < 0)
		result = dt1;
	else
		result = dt2;
	PG_RETURN_TIMESTAMP(result);
}

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

	if (timestamp_cmp_internal(dt1, dt2) > 0)
		result = dt1;
	else
		result = dt2;
	PG_RETURN_TIMESTAMP(result);
}


Datum
timestamp_mi(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);
	Interval   *result;

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

	if (TIMESTAMP_NOT_FINITE(dt1) || TIMESTAMP_NOT_FINITE(dt2))
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("cannot subtract infinite timestamps")));

	result->time = dt1 - dt2;

	result->month = 0;
	result->day = 0;

	/*
	 * This is wrong, but removing it breaks a lot of regression tests. For
	 * example:
	 *
	 * test=> SET timezone = 'EST5EDT'; test=> SELECT test-> ('2005-10-30
	 * 13:22:00-05'::timestamptz - test(>  '2005-10-29
	 * 13:22:00-04'::timestamptz); ?column? ---------------- 1 day 01:00:00 (1
	 * row)
	 *
	 * so adding that to the first timestamp gets:
	 *
	 * test=> SELECT test-> ('2005-10-29 13:22:00-04'::timestamptz + test(>
	 * ('2005-10-30 13:22:00-05'::timestamptz - test(>	'2005-10-29
	 * 13:22:00-04'::timestamptz)) at time zone 'EST'; timezone
	 * -------------------- 2005-10-30 14:22:00 (1 row)
	 */
	result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
												 IntervalPGetDatum(result)));

	PG_RETURN_INTERVAL_P(result);
}

/*
 *	interval_justify_hours()
 *
 *	Adjust interval so 'time' contains less than a whole day, adding
 *	the excess to 'day'.  This is useful for
 *	situations (such as non-TZ) where '1 day' = '24 hours' is valid,
 *	e.g. interval subtraction and division.
 */
Datum
interval_justify_hours(PG_FUNCTION_ARGS)
{
	Interval   *span = PG_GETARG_INTERVAL_P(0);
	Interval   *result;

#ifdef HAVE_INT64_TIMESTAMP
	int64		wholeday;
#else
	double		wholeday;
#endif

	result = (Interval *) palloc(sizeof(Interval));
	result->month = span->month;
	result->day = span->day;
	result->time = span->time;

#ifdef HAVE_INT64_TIMESTAMP
	TMODULO(result->time, wholeday, USECS_PER_DAY);
#else
	TMODULO(result->time, wholeday, (double) SECS_PER_DAY);
#endif
	result->day += wholeday;	/* could overflow... */

	PG_RETURN_INTERVAL_P(result);
}

/*
 *	interval_justify_days()
 *
 *	Adjust interval so 'day' contains less than 30 days, adding
 *	the excess to 'month'.
 */
Datum
interval_justify_days(PG_FUNCTION_ARGS)
{
	Interval   *span = PG_GETARG_INTERVAL_P(0);
	Interval   *result;
	int32		wholemonth;

	result = (Interval *) palloc(sizeof(Interval));
	result->month = span->month;
	result->day = span->day;
	result->time = span->time;

	wholemonth = result->day / DAYS_PER_MONTH;
	result->day -= wholemonth * DAYS_PER_MONTH;
	result->month += wholemonth;

	PG_RETURN_INTERVAL_P(result);
}

/* timestamp_pl_interval()
 * Add a interval to a timestamp data type.
 * Note that interval has provisions for qualitative year/month and day
 *	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.
 * To add a day, increment the mday, and use the same time of day.
 * Lastly, add in the "quantitative time".
 */
Datum
timestamp_pl_interval(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	Timestamp	result;

	if (TIMESTAMP_NOT_FINITE(timestamp))
		result = timestamp;
	else
	{
		if (span->month != 0)
		{
			struct pg_tm tt,
					   *tm = &tt;
			fsec_t		fsec;

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

			tm->tm_mon += span->month;
			if (tm->tm_mon > MONTHS_PER_YEAR)
			{
				tm->tm_year += (tm->tm_mon - 1) / MONTHS_PER_YEAR;
				tm->tm_mon = ((tm->tm_mon - 1) % MONTHS_PER_YEAR) + 1;
			}
			else if (tm->tm_mon < 1)
			{
				tm->tm_year += tm->tm_mon / MONTHS_PER_YEAR - 1;
				tm->tm_mon = tm->tm_mon % MONTHS_PER_YEAR + MONTHS_PER_YEAR;
			}

			/* 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]);

			if (tm2timestamp(tm, fsec, NULL, &timestamp) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range")));
		}

		if (span->day != 0)
		{
			struct pg_tm tt,
					   *tm = &tt;
			fsec_t		fsec;
			int			julian;

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

			/* Add days by converting to and from julian */
			julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + span->day;
			j2date(julian, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);

			if (tm2timestamp(tm, fsec, NULL, &timestamp) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range")));
		}

		timestamp += span->time;
		result = timestamp;
	}

	PG_RETURN_TIMESTAMP(result);
}

Datum
timestamp_mi_interval(PG_FUNCTION_ARGS)
{
	Timestamp	timestamp = PG_GETARG_TIMESTAMP(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	Interval	tspan;

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

	return DirectFunctionCall2(timestamp_pl_interval,
							   TimestampGetDatum(timestamp),
							   PointerGetDatum(&tspan));
}


/* timestamptz_pl_interval()
 * Add a interval to a timestamp with time zone data type.
 * Note that interval 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.
 * Lastly, add in the "quantitative time".
 */
Datum
timestamptz_pl_interval(PG_FUNCTION_ARGS)
{
	TimestampTz timestamp = PG_GETARG_TIMESTAMPTZ(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	TimestampTz result;
	int			tz;
	char	   *tzn;

	if (TIMESTAMP_NOT_FINITE(timestamp))
		result = timestamp;
	else
	{
		if (span->month != 0)
		{
			struct pg_tm tt,
					   *tm = &tt;
			fsec_t		fsec;

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

			tm->tm_mon += span->month;
			if (tm->tm_mon > MONTHS_PER_YEAR)
			{
				tm->tm_year += (tm->tm_mon - 1) / MONTHS_PER_YEAR;
				tm->tm_mon = ((tm->tm_mon - 1) % MONTHS_PER_YEAR) + 1;
			}
			else if (tm->tm_mon < 1)
			{
				tm->tm_year += tm->tm_mon / MONTHS_PER_YEAR - 1;
				tm->tm_mon = tm->tm_mon % MONTHS_PER_YEAR + MONTHS_PER_YEAR;
			}

			/* 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]);

			tz = DetermineTimeZoneOffset(tm, global_timezone);

			if (tm2timestamp(tm, fsec, &tz, &timestamp) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range")));
		}

		if (span->day != 0)
		{
			struct pg_tm tt,
					   *tm = &tt;
			fsec_t		fsec;
			int			julian;

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

			/* Add days by converting to and from julian */
			julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + span->day;
			j2date(julian, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);

			tz = DetermineTimeZoneOffset(tm, global_timezone);

			if (tm2timestamp(tm, fsec, &tz, &timestamp) != 0)
				ereport(ERROR,
						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
						 errmsg("timestamp out of range")));
		}

		timestamp += span->time;
		result = timestamp;
	}

	PG_RETURN_TIMESTAMP(result);
}

Datum