timestamp.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

timestamptz_mi_interval(PG_FUNCTION_ARGS)
{
	TimestampTz timestamp = PG_GETARG_TIMESTAMPTZ(0);
	Interval   *span = PG_GETARG_INTERVAL_P(1);
	Interval	tspan;

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

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


Datum
interval_um(PG_FUNCTION_ARGS)
{
	Interval   *interval = PG_GETARG_INTERVAL_P(0);
	Interval   *result;

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

	result->time = -interval->time;
	result->day = -interval->day;
	result->month = -interval->month;

	PG_RETURN_INTERVAL_P(result);
}


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

	/* use interval_cmp_internal to be sure this agrees with comparisons */
	if (interval_cmp_internal(interval1, interval2) < 0)
		result = interval1;
	else
		result = interval2;
	PG_RETURN_INTERVAL_P(result);
}

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

	if (interval_cmp_internal(interval1, interval2) > 0)
		result = interval1;
	else
		result = interval2;
	PG_RETURN_INTERVAL_P(result);
}

Datum
interval_pl(PG_FUNCTION_ARGS)
{
	Interval   *span1 = PG_GETARG_INTERVAL_P(0);
	Interval   *span2 = PG_GETARG_INTERVAL_P(1);
	Interval   *result;

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

	result->month = span1->month + span2->month;
	result->day = span1->day + span2->day;
	result->time = span1->time + span2->time;

	PG_RETURN_INTERVAL_P(result);
}

Datum
interval_mi(PG_FUNCTION_ARGS)
{
	Interval   *span1 = PG_GETARG_INTERVAL_P(0);
	Interval   *span2 = PG_GETARG_INTERVAL_P(1);
	Interval   *result;

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

	result->month = span1->month - span2->month;
	result->day = span1->day - span2->day;
	result->time = span1->time - span2->time;

	PG_RETURN_INTERVAL_P(result);
}

Datum
interval_mul(PG_FUNCTION_ARGS)
{
	Interval   *span = PG_GETARG_INTERVAL_P(0);
	float8		factor = PG_GETARG_FLOAT8(1);
	double		month_remainder,
				day_remainder,
				month_remainder_days;
	Interval   *result;

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

	month_remainder = span->month * factor;
	day_remainder = span->day * factor;
	result->month = (int32) month_remainder;
	result->day = (int32) day_remainder;
	month_remainder -= result->month;
	day_remainder -= result->day;

	/*
	 * The above correctly handles the whole-number part of the month and day
	 * products, but we have to do something with any fractional part
	 * resulting when the factor is nonintegral.  We cascade the fractions
	 * down to lower units using the conversion factors DAYS_PER_MONTH and
	 * SECS_PER_DAY.  Note we do NOT cascade up, since we are not forced to do
	 * so by the representation.  The user can choose to cascade up later,
	 * using justify_hours and/or justify_days.
	 */

	/* fractional months full days into days */
	month_remainder_days = month_remainder * DAYS_PER_MONTH;
	result->day += (int32) month_remainder_days;
	/* fractional months partial days into time */
	day_remainder += month_remainder_days - (int32) month_remainder_days;

#ifdef HAVE_INT64_TIMESTAMP
	result->time = rint(span->time * factor + day_remainder * USECS_PER_DAY);
#else
	result->time = span->time * factor + day_remainder * SECS_PER_DAY;
#endif

	PG_RETURN_INTERVAL_P(result);
}

Datum
mul_d_interval(PG_FUNCTION_ARGS)
{
	/* Args are float8 and Interval *, but leave them as generic Datum */
	Datum		factor = PG_GETARG_DATUM(0);
	Datum		span = PG_GETARG_DATUM(1);

	return DirectFunctionCall2(interval_mul, span, factor);
}

Datum
interval_div(PG_FUNCTION_ARGS)
{
	Interval   *span = PG_GETARG_INTERVAL_P(0);
	float8		factor = PG_GETARG_FLOAT8(1);
	double		month_remainder,
				day_remainder,
				month_remainder_days;
	Interval   *result;

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

	if (factor == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_DIVISION_BY_ZERO),
				 errmsg("division by zero")));

	month_remainder = span->month / factor;
	day_remainder = span->day / factor;
	result->month = (int32) month_remainder;
	result->day = (int32) day_remainder;
	month_remainder -= result->month;
	day_remainder -= result->day;

	/*
	 * Handle any fractional parts the same way as in interval_mul.
	 */

	/* fractional months full days into days */
	month_remainder_days = month_remainder * DAYS_PER_MONTH;
	result->day += (int32) month_remainder_days;
	/* fractional months partial days into time */
	day_remainder += month_remainder_days - (int32) month_remainder_days;

#ifdef HAVE_INT64_TIMESTAMP
	result->time = rint(span->time / factor + day_remainder * USECS_PER_DAY);
#else
	result->time = span->time / factor + day_remainder * SECS_PER_DAY;
#endif

	PG_RETURN_INTERVAL_P(result);
}

/*
 * interval_accum and interval_avg implement the AVG(interval) aggregate.
 *
 * The transition datatype for this aggregate is a 2-element array of
 * intervals, where the first is the running sum and the second contains
 * the number of values so far in its 'time' field.  This is a bit ugly
 * but it beats inventing a specialized datatype for the purpose.
 */

Datum
interval_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	Interval   *newval = PG_GETARG_INTERVAL_P(1);
	Datum	   *transdatums;
	int			ndatums;
	Interval	sumX,
				N;
	Interval   *newsum;
	ArrayType  *result;

	deconstruct_array(transarray,
					  INTERVALOID, sizeof(Interval), false, 'd',
					  &transdatums, &ndatums);
	if (ndatums != 2)
		elog(ERROR, "expected 2-element interval array");

	/*
	 * XXX memcpy, instead of just extracting a pointer, to work around buggy
	 * array code: it won't ensure proper alignment of Interval objects on
	 * machines where double requires 8-byte alignment. That should be fixed,
	 * but in the meantime...
	 *
	 * Note: must use DatumGetPointer here, not DatumGetIntervalP, else some
	 * compilers optimize into double-aligned load/store anyway.
	 */
	memcpy((void *) &sumX, DatumGetPointer(transdatums[0]), sizeof(Interval));
	memcpy((void *) &N, DatumGetPointer(transdatums[1]), sizeof(Interval));

	newsum = DatumGetIntervalP(DirectFunctionCall2(interval_pl,
												   IntervalPGetDatum(&sumX),
												 IntervalPGetDatum(newval)));
	N.time += 1;

	transdatums[0] = IntervalPGetDatum(newsum);
	transdatums[1] = IntervalPGetDatum(&N);

	result = construct_array(transdatums, 2,
							 INTERVALOID, sizeof(Interval), false, 'd');

	PG_RETURN_ARRAYTYPE_P(result);
}

Datum
interval_avg(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	Datum	   *transdatums;
	int			ndatums;
	Interval	sumX,
				N;

	deconstruct_array(transarray,
					  INTERVALOID, sizeof(Interval), false, 'd',
					  &transdatums, &ndatums);
	if (ndatums != 2)
		elog(ERROR, "expected 2-element interval array");

	/*
	 * XXX memcpy, instead of just extracting a pointer, to work around buggy
	 * array code: it won't ensure proper alignment of Interval objects on
	 * machines where double requires 8-byte alignment. That should be fixed,
	 * but in the meantime...
	 *
	 * Note: must use DatumGetPointer here, not DatumGetIntervalP, else some
	 * compilers optimize into double-aligned load/store anyway.
	 */
	memcpy((void *) &sumX, DatumGetPointer(transdatums[0]), sizeof(Interval));
	memcpy((void *) &N, DatumGetPointer(transdatums[1]), sizeof(Interval));

	/* SQL92 defines AVG of no values to be NULL */
	if (N.time == 0)
		PG_RETURN_NULL();

	return DirectFunctionCall2(interval_div,
							   IntervalPGetDatum(&sumX),
							   Float8GetDatum(N.time));
}


/* timestamp_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.
 */
Datum
timestamp_age(PG_FUNCTION_ARGS)
{
	Timestamp	dt1 = PG_GETARG_TIMESTAMP(0);
	Timestamp	dt2 = PG_GETARG_TIMESTAMP(1);
	Interval   *result;
	fsec_t		fsec,
				fsec1,
				fsec2;
	struct pg_tm tt,
			   *tm = &tt;
	struct pg_tm tt1,
			   *tm1 = &tt1;
	struct pg_tm tt2,
			   *tm2 = &tt2;

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

	if (timestamp2tm(dt1, NULL, tm1, &fsec1, NULL, NULL) == 0 &&
		timestamp2tm(dt2, NULL, tm2, &fsec2, NULL, 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;
		}

		while (tm->tm_sec < 0)
		{
			tm->tm_sec += SECS_PER_MINUTE;
			tm->tm_min--;
		}

		while (tm->tm_min < 0)
		{
			tm->tm_min += MINS_PER_HOUR;
			tm->tm_hour--;
		}

		while (tm->tm_hour < 0)
		{
			tm->tm_hour += HOURS_PER_DAY;
			tm->tm_mday--;
		}

		while (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--;
			}
		}

		while (tm->tm_mon < 0)
		{
			tm->tm_mon += MONTHS_PER_YEAR;
			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 (tm2interval(tm, fsec, result) != 0)
			ereport(ERROR,
					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
					 errmsg("interval out of range")));
	}
	else
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	PG_RETURN_INTERVAL_P(result);
}


/* timestamptz_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.
 */
Datum
timestamptz_age(PG_FUNCTION_ARGS)
{
	TimestampTz dt1 = PG_GETARG_TIMESTAMPTZ(0);
	TimestampTz dt2 = PG_GETARG_TIMESTAMPTZ(1);
	Interval   *result;
	fsec_t		fsec,
				fsec1,
				fsec2;
	struct pg_tm tt,
			   *tm = &tt;
	struct pg_tm tt1,
			   *tm1 = &tt1;
	struct pg_tm tt2,
			   *tm2 = &tt2;
	int			tz1;
	int			tz2;
	char	   *tzn;

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

	if (timestamp2tm(dt1, &tz1, tm1, &fsec1, &tzn, NULL) == 0 &&
		timestamp2tm(dt2, &tz2, tm2, &fsec2, &tzn, 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;
		}

		while (tm->tm_sec < 0)
		{
			tm->tm_sec += SECS_PER_MINUTE;
			tm->tm_min--;
		}

		while (tm->tm_min < 0)
		{
			tm->tm_min += MINS_PER_HOUR;
			tm->tm_hour--;
		}

		while (tm->tm_hour < 0)
		{
			tm->tm_hour += HOURS_PER_DAY;
			tm->tm_mday--;
		}

		while (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--;
			}
		}

		while (tm->tm_mon < 0)
		{
			tm->tm_mon += MONTHS_PER_YEAR;
			tm->tm_year--;
		}

		/*
		 * Note: we deliberately ignore any difference between tz1 and tz2.
		 */

		/* 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 (tm2interval(tm, fsec, result) != 0)
			ereport(ERROR,
					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
					 errmsg("interval out of range")));
	}
	else
		ereport(ERROR,
				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
				 errmsg("timestamp out of range")));

	PG_RETURN_INTERVAL_P(result);
}


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


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

	str = DatumGetCString(DirectFunctionCall1(timestamp_out, timestamp));

	len = (strlen(str) + VARHDRSZ);

	result = palloc(len);

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

	pfree(str);

	PG_RETURN_TEXT_P(result);
}


/* text_timestamp()
 * Convert text string to timestamp.
 * Text type is not null terminated, so use temporary string
 *	then call the standard input routine.
 */
Datum
text_timestamp(PG_FUNCTION_ARGS)
{
	text	   *str = PG_GETARG_TEXT_P(0);
	int			i;
	char	   *sp,
			   *dp