timestamp.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

}

/* interval_out()
 * Convert a time span to external form.
 */
Datum
interval_out(PG_FUNCTION_ARGS)
{
	Interval   *span = PG_GETARG_INTERVAL_P(0);
	char	   *result;
	struct pg_tm tt,
			   *tm = &tt;
	fsec_t		fsec;
	char		buf[MAXDATELEN + 1];

	if (interval2tm(*span, tm, &fsec) != 0)
		elog(ERROR, "could not convert interval to tm");

	if (EncodeInterval(tm, fsec, DateStyle, buf) != 0)
		elog(ERROR, "could not format interval");

	result = pstrdup(buf);
	PG_RETURN_CSTRING(result);
}

/*
 *		interval_recv			- converts external binary format to interval
 */
Datum
interval_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);

#ifdef NOT_USED
	Oid			typelem = PG_GETARG_OID(1);
#endif
	int32		typmod = PG_GETARG_INT32(2);
	Interval   *interval;

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

#ifdef HAVE_INT64_TIMESTAMP
	interval->time = pq_getmsgint64(buf);
#else
	interval->time = pq_getmsgfloat8(buf);
#endif
	interval->day = pq_getmsgint(buf, sizeof(interval->day));
	interval->month = pq_getmsgint(buf, sizeof(interval->month));

	AdjustIntervalForTypmod(interval, typmod);

	PG_RETURN_INTERVAL_P(interval);
}

/*
 *		interval_send			- converts interval to binary format
 */
Datum
interval_send(PG_FUNCTION_ARGS)
{
	Interval   *interval = PG_GETARG_INTERVAL_P(0);
	StringInfoData buf;

	pq_begintypsend(&buf);
#ifdef HAVE_INT64_TIMESTAMP
	pq_sendint64(&buf, interval->time);
#else
	pq_sendfloat8(&buf, interval->time);
#endif
	pq_sendint(&buf, interval->day, sizeof(interval->day));
	pq_sendint(&buf, interval->month, sizeof(interval->month));
	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


/* interval_scale()
 * Adjust interval type for specified fields.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
interval_scale(PG_FUNCTION_ARGS)
{
	Interval   *interval = PG_GETARG_INTERVAL_P(0);
	int32		typmod = PG_GETARG_INT32(1);
	Interval   *result;

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

	AdjustIntervalForTypmod(result, typmod);

	PG_RETURN_INTERVAL_P(result);
}

/*
 *	Adjust interval for specified precision, in both YEAR to SECOND
 *	range and sub-second precision.
 */
static void
AdjustIntervalForTypmod(Interval *interval, int32 typmod)
{
#ifdef HAVE_INT64_TIMESTAMP
	static const int64 IntervalScales[MAX_INTERVAL_PRECISION + 1] = {
		INT64CONST(1000000),
		INT64CONST(100000),
		INT64CONST(10000),
		INT64CONST(1000),
		INT64CONST(100),
		INT64CONST(10),
		INT64CONST(1)
	};

	static const int64 IntervalOffsets[MAX_INTERVAL_PRECISION + 1] = {
		INT64CONST(500000),
		INT64CONST(50000),
		INT64CONST(5000),
		INT64CONST(500),
		INT64CONST(50),
		INT64CONST(5),
		INT64CONST(0)
	};
#else
	static const double IntervalScales[MAX_INTERVAL_PRECISION + 1] = {
		1,
		10,
		100,
		1000,
		10000,
		100000,
		1000000
	};
#endif

	/*
	 * Unspecified range and precision? Then not necessary to adjust. Setting
	 * typmod to -1 is the convention for all types.
	 */
	if (typmod != -1)
	{
		int			range = INTERVAL_RANGE(typmod);
		int			precision = INTERVAL_PRECISION(typmod);

		if (range == INTERVAL_FULL_RANGE)
		{
			/* Do nothing... */
		}
		else if (range == INTERVAL_MASK(YEAR))
		{
			interval->month = (interval->month / MONTHS_PER_YEAR) * MONTHS_PER_YEAR;
			interval->day = 0;
			interval->time = 0;
		}
		else if (range == INTERVAL_MASK(MONTH))
		{
			interval->month %= MONTHS_PER_YEAR;
			interval->day = 0;
			interval->time = 0;
		}
		/* YEAR TO MONTH */
		else if (range == (INTERVAL_MASK(YEAR) | INTERVAL_MASK(MONTH)))
		{
			/* month is already year to month */
			interval->day = 0;
			interval->time = 0;
		}
		else if (range == INTERVAL_MASK(DAY))
		{
			interval->month = 0;
			interval->time = 0;
		}
		else if (range == INTERVAL_MASK(HOUR))
		{
			interval->month = 0;
			interval->day = 0;

#ifdef HAVE_INT64_TIMESTAMP
			interval->time = (interval->time / USECS_PER_HOUR) *
				USECS_PER_HOUR;
#else
			interval->time = ((int) (interval->time / SECS_PER_HOUR)) * (double) SECS_PER_HOUR;
#endif
		}
		else if (range == INTERVAL_MASK(MINUTE))
		{
#ifdef HAVE_INT64_TIMESTAMP
			int64		hour;
#else
			double		hour;
#endif

			interval->month = 0;
			interval->day = 0;

#ifdef HAVE_INT64_TIMESTAMP
			hour = interval->time / USECS_PER_HOUR;
			interval->time -= hour * USECS_PER_HOUR;
			interval->time = (interval->time / USECS_PER_MINUTE) *
				USECS_PER_MINUTE;
#else
			TMODULO(interval->time, hour, (double) SECS_PER_HOUR);
			interval->time = ((int) (interval->time / SECS_PER_MINUTE)) * (double) SECS_PER_MINUTE;
#endif
		}
		else if (range == INTERVAL_MASK(SECOND))
		{
#ifdef HAVE_INT64_TIMESTAMP
			int64		minute;
#else
			double		minute;
#endif

			interval->month = 0;
			interval->day = 0;

#ifdef HAVE_INT64_TIMESTAMP
			minute = interval->time / USECS_PER_MINUTE;
			interval->time -= minute * USECS_PER_MINUTE;
#else
			TMODULO(interval->time, minute, (double) SECS_PER_MINUTE);
			/* return subseconds too */
#endif
		}
		/* DAY TO HOUR */
		else if (range == (INTERVAL_MASK(DAY) |
						   INTERVAL_MASK(HOUR)))
		{
			interval->month = 0;

#ifdef HAVE_INT64_TIMESTAMP
			interval->time = (interval->time / USECS_PER_HOUR) *
				USECS_PER_HOUR;
#else
			interval->time = ((int) (interval->time / SECS_PER_HOUR)) * (double) SECS_PER_HOUR;
#endif
		}
		/* DAY TO MINUTE */
		else if (range == (INTERVAL_MASK(DAY) |
						   INTERVAL_MASK(HOUR) |
						   INTERVAL_MASK(MINUTE)))
		{
			interval->month = 0;

#ifdef HAVE_INT64_TIMESTAMP
			interval->time = (interval->time / USECS_PER_MINUTE) *
				USECS_PER_MINUTE;
#else
			interval->time = ((int) (interval->time / SECS_PER_MINUTE)) * (double) SECS_PER_MINUTE;
#endif
		}
		/* DAY TO SECOND */
		else if (range == (INTERVAL_MASK(DAY) |
						   INTERVAL_MASK(HOUR) |
						   INTERVAL_MASK(MINUTE) |
						   INTERVAL_MASK(SECOND)))
			interval->month = 0;

		/* HOUR TO MINUTE */
		else if (range == (INTERVAL_MASK(HOUR) |
						   INTERVAL_MASK(MINUTE)))
		{
			interval->month = 0;
			interval->day = 0;

#ifdef HAVE_INT64_TIMESTAMP
			interval->time = (interval->time / USECS_PER_MINUTE) *
				USECS_PER_MINUTE;
#else
			interval->time = ((int) (interval->time / SECS_PER_MINUTE)) * (double) SECS_PER_MINUTE;
#endif
		}
		/* HOUR TO SECOND */
		else if (range == (INTERVAL_MASK(HOUR) |
						   INTERVAL_MASK(MINUTE) |
						   INTERVAL_MASK(SECOND)))
		{
			interval->month = 0;
			interval->day = 0;
			/* return subseconds too */
		}
		/* MINUTE TO SECOND */
		else if (range == (INTERVAL_MASK(MINUTE) |
						   INTERVAL_MASK(SECOND)))
		{
#ifdef HAVE_INT64_TIMESTAMP
			int64		hour;
#else
			double		hour;
#endif

			interval->month = 0;
			interval->day = 0;

#ifdef HAVE_INT64_TIMESTAMP
			hour = interval->time / USECS_PER_HOUR;
			interval->time -= hour * USECS_PER_HOUR;
#else
			TMODULO(interval->time, hour, (double) SECS_PER_HOUR);
#endif
		}
		else
			elog(ERROR, "unrecognized interval typmod: %d", typmod);

		/* Need to adjust subsecond precision? */
		if (precision != INTERVAL_FULL_PRECISION)
		{
			if (precision < 0 || precision > MAX_INTERVAL_PRECISION)
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				   errmsg("interval(%d) precision must be between %d and %d",
						  precision, 0, MAX_INTERVAL_PRECISION)));

			/*
			 * Note: this round-to-nearest code is not completely consistent
			 * about rounding values that are exactly halfway between integral
			 * values.	On most platforms, rint() will implement
			 * round-to-nearest-even, but the integer code always rounds up
			 * (away from zero).  Is it worth trying to be consistent?
			 */
#ifdef HAVE_INT64_TIMESTAMP
			if (interval->time >= INT64CONST(0))
			{
				interval->time = ((interval->time +
								   IntervalOffsets[precision]) /
								  IntervalScales[precision]) *
					IntervalScales[precision];
			}
			else
			{
				interval->time = -(((-interval->time +
									 IntervalOffsets[precision]) /
									IntervalScales[precision]) *
								   IntervalScales[precision]);
			}
#else
			interval->time = rint(((double) interval->time) *
								  IntervalScales[precision]) /
				IntervalScales[precision];
#endif
		}
	}

	return;
}


/* EncodeSpecialTimestamp()
 * Convert reserved timestamp data type to string.
 */
static int
EncodeSpecialTimestamp(Timestamp dt, char *str)
{
	if (TIMESTAMP_IS_NOBEGIN(dt))
		strcpy(str, EARLY);
	else if (TIMESTAMP_IS_NOEND(dt))
		strcpy(str, LATE);
	else
		return FALSE;

	return TRUE;
}	/* EncodeSpecialTimestamp() */

Datum
now(PG_FUNCTION_ARGS)
{
	PG_RETURN_TIMESTAMPTZ(GetCurrentTransactionStartTimestamp());
}

Datum
pgsql_postmaster_start_time(PG_FUNCTION_ARGS)
{
	PG_RETURN_TIMESTAMPTZ(PgStartTime);
}

/*
 * GetCurrentTimestamp -- get the current operating system time
 *
 * Result is in the form of a TimestampTz value, and is expressed to the
 * full precision of the gettimeofday() syscall
 */
TimestampTz
GetCurrentTimestamp(void)
{
	TimestampTz result;
	struct timeval tp;

	gettimeofday(&tp, NULL);

	result = (TimestampTz) tp.tv_sec -
		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);

#ifdef HAVE_INT64_TIMESTAMP
	result = (result * USECS_PER_SEC) + tp.tv_usec;
#else
	result = result + (tp.tv_usec / 1000000.0);
#endif

	return result;
}


/*
 * Convert a time_t to TimestampTz.
 *
 * We do not use time_t internally in Postgres, but this is provided for use
 * by functions that need to interpret, say, a stat(2) result.
 */
TimestampTz
time_t_to_timestamptz(time_t tm)
{
	TimestampTz result;

	result = (TimestampTz) tm -
		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);

#ifdef HAVE_INT64_TIMESTAMP
	result *= USECS_PER_SEC;
#endif

	return result;
}


void
dt2time(Timestamp jd, int *hour, int *min, int *sec, fsec_t *fsec)
{
#ifdef HAVE_INT64_TIMESTAMP
	int64		time;
#else
	double		time;
#endif

	time = jd;

#ifdef HAVE_INT64_TIMESTAMP
	*hour = time / USECS_PER_HOUR;
	time -= (*hour) * USECS_PER_HOUR;
	*min = time / USECS_PER_MINUTE;
	time -= (*min) * USECS_PER_MINUTE;
	*sec = time / USECS_PER_SEC;
	*fsec = time - (*sec * USECS_PER_SEC);
#else
	*hour = time / SECS_PER_HOUR;
	time -= (*hour) * SECS_PER_HOUR;
	*min = time / SECS_PER_MINUTE;
	time -= (*min) * SECS_PER_MINUTE;
	*sec = time;
	*fsec = time - *sec;
#endif
}	/* dt2time() */


/*
 * timestamp2tm() - Convert timestamp 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
 *
 * If attimezone is NULL, the global timezone (including possibly brute forced
 * timezone) will be used.
 */
int
timestamp2tm(Timestamp dt, int *tzp, struct pg_tm * tm, fsec_t *fsec, char **tzn, pg_tz *attimezone)
{
	Timestamp	date;
	Timestamp	time;
	pg_time_t	utime;

	/*
	 * If HasCTZSet is true then we have a brute force time zone specified. Go
	 * ahead and rotate to the local time zone since we will later bypass any
	 * calls which adjust the tm fields.
	 */
	if (attimezone == NULL && HasCTZSet && tzp != NULL)
	{
#ifdef HAVE_INT64_TIMESTAMP
		dt -= CTimeZone * USECS_PER_SEC;
#else
		dt -= CTimeZone;
#endif
	}

#ifdef HAVE_INT64_TIMESTAMP
	time = dt;
	TMODULO(time, date, USECS_PER_DAY);

	if (time < INT64CONST(0))
	{
		time += USECS_PER_DAY;
		date -= 1;
	}

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

	/* Julian day routine does not work for negative Julian days */
	if (date < 0 || date > (Timestamp) INT_MAX)
		return -1;

	j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
	dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);
#else
	time = dt;
	TMODULO(time, date, (double) SECS_PER_DAY);

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

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

recalc_d:
	/* Julian day routine does not work for negative Julian days */
	if (date < 0 || date > (Timestamp) INT_MAX)
		return -1;

	j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
recalc_t:
	dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);

	*fsec = TSROUND(*fsec);
	/* roundoff may need to propagate to higher-order fields */
	if (*fsec >= 1.0)
	{
		time = ceil(time);
		if (time >= (double) SECS_PER_DAY)
		{
			time = 0;
			date += 1;
			goto recalc_d;
		}
		goto recalc_t;
	}
#endif

	/* Done if no TZ conversion wanted */
	if (tzp == NULL)
	{
		tm->tm_isdst = -1;
		tm->tm_gmtoff = 0;
		tm->tm_zone = NULL;
		if (tzn != NULL)
			*tzn = NULL;
		return 0;
	}

	/*
	 * We have a brute force time zone per SQL99? Then use it without change
	 * since we have already rotated to the time zone.