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/*-------------------------------------------------------------------------
*
* timestamp.h
* Timestamp and Interval typedefs and related macros.
*
* Note: this file must be includable in both frontend and backend contexts.
*
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/datatype/timestamp.h
*
*-------------------------------------------------------------------------
*/
#ifndef DATATYPE_TIMESTAMP_H
#define DATATYPE_TIMESTAMP_H
#include <math.h>
#include <limits.h>
#include <float.h>
/*
* Timestamp represents absolute time.
*
* Interval represents delta time. Keep track of months (and years), days,
* and hours/minutes/seconds separately since the elapsed time spanned is
* unknown until instantiated relative to an absolute time.
*
* Note that Postgres uses "time interval" to mean a bounded interval,
* consisting of a beginning and ending time, not a time span - thomas 97/03/20
*
* We have two implementations, one that uses int64 values with units of
* microseconds, and one that uses double values with units of seconds.
*
* TimeOffset and fsec_t are convenience typedefs for temporary variables
* that are of different types in the two cases. Do not use fsec_t in values
* stored on-disk, since it is not the same size in both implementations.
* Also, fsec_t is only meant for *fractional* seconds; beware of overflow
* if the value you need to store could be many seconds.
*/
#ifdef HAVE_INT64_TIMESTAMP
typedef int64 Timestamp;
typedef int64 TimestampTz;
typedef int64 TimeOffset;
typedef int32 fsec_t; /* fractional seconds (in microseconds) */
#else
typedef double Timestamp;
typedef double TimestampTz;
typedef double TimeOffset;
typedef double fsec_t; /* fractional seconds (in seconds) */
#endif
typedef struct
{
TimeOffset time; /* all time units other than days, months and
* years */
int32 day; /* days, after time for alignment */
int32 month; /* months and years, after time for alignment */
} Interval;
#define MAX_TIMESTAMP_PRECISION 6
#define MAX_INTERVAL_PRECISION 6
/*
* Round off to MAX_TIMESTAMP_PRECISION decimal places.
* Note: this is also used for rounding off intervals.
*/
#define TS_PREC_INV 1000000.0
#define TSROUND(j) (rint(((double) (j)) * TS_PREC_INV) / TS_PREC_INV)
/*
* Assorted constants for datetime-related calculations
*/
#define DAYS_PER_YEAR 365.25 /* assumes leap year every four years */
#define MONTHS_PER_YEAR 12
/*
* DAYS_PER_MONTH is very imprecise. The more accurate value is
* 365.2425/12 = 30.436875, or '30 days 10:29:06'. Right now we only
* return an integral number of days, but someday perhaps we should
* also return a 'time' value to be used as well. ISO 8601 suggests
* 30 days.
*/
#define DAYS_PER_MONTH 30 /* assumes exactly 30 days per month */
#define HOURS_PER_DAY 24 /* assume no daylight savings time changes */
/*
* This doesn't adjust for uneven daylight savings time intervals or leap
* seconds, and it crudely estimates leap years. A more accurate value
* for days per years is 365.2422.
*/
#define SECS_PER_YEAR (36525 * 864) /* avoid floating-point computation */
#define SECS_PER_DAY 86400
#define SECS_PER_HOUR 3600
#define SECS_PER_MINUTE 60
#define MINS_PER_HOUR 60
#define USECS_PER_DAY INT64CONST(86400000000)
#define USECS_PER_HOUR INT64CONST(3600000000)
#define USECS_PER_MINUTE INT64CONST(60000000)
#define USECS_PER_SEC INT64CONST(1000000)
/*
* We allow numeric timezone offsets up to 15:59:59 either way from Greenwich.
* Currently, the record holders for wackiest offsets in actual use are zones
* Asia/Manila, at -15:56:00 until 1844, and America/Metlakatla, at +15:13:42
* until 1867. If we were to reject such values we would fail to dump and
* restore old timestamptz values with these zone settings.
*/
#define MAX_TZDISP_HOUR 15 /* maximum allowed hour part */
#define TZDISP_LIMIT ((MAX_TZDISP_HOUR + 1) * SECS_PER_HOUR)
/*
* DT_NOBEGIN represents timestamp -infinity; DT_NOEND represents +infinity
*/
#ifdef HAVE_INT64_TIMESTAMP
#define DT_NOBEGIN (-INT64CONST(0x7fffffffffffffff) - 1)
#define DT_NOEND (INT64CONST(0x7fffffffffffffff))
#else /* !HAVE_INT64_TIMESTAMP */
#ifdef HUGE_VAL
#define DT_NOBEGIN (-HUGE_VAL)
#define DT_NOEND (HUGE_VAL)
#else
#define DT_NOBEGIN (-DBL_MAX)
#define DT_NOEND (DBL_MAX)
#endif
#endif /* HAVE_INT64_TIMESTAMP */
#define TIMESTAMP_NOBEGIN(j) \
do {(j) = DT_NOBEGIN;} while (0)
#define TIMESTAMP_IS_NOBEGIN(j) ((j) == DT_NOBEGIN)
#define TIMESTAMP_NOEND(j) \
do {(j) = DT_NOEND;} while (0)
#define TIMESTAMP_IS_NOEND(j) ((j) == DT_NOEND)
#define TIMESTAMP_NOT_FINITE(j) (TIMESTAMP_IS_NOBEGIN(j) || TIMESTAMP_IS_NOEND(j))
/*
* Julian date support.
*
* IS_VALID_JULIAN checks the minimum date exactly, but is a bit sloppy
* about the maximum, since it's far enough out to not be especially
* interesting.
*/
#define JULIAN_MINYEAR (-4713)
#define JULIAN_MINMONTH (11)
#define JULIAN_MINDAY (24)
#define JULIAN_MAXYEAR (5874898)
#define IS_VALID_JULIAN(y,m,d) \
(((y) > JULIAN_MINYEAR \
|| ((y) == JULIAN_MINYEAR && \
((m) > JULIAN_MINMONTH \
|| ((m) == JULIAN_MINMONTH && (d) >= JULIAN_MINDAY)))) \
&& (y) < JULIAN_MAXYEAR)
#define JULIAN_MAX (2147483494) /* == date2j(JULIAN_MAXYEAR, 1, 1) */
/* Julian-date equivalents of Day 0 in Unix and Postgres reckoning */
#define UNIX_EPOCH_JDATE 2440588 /* == date2j(1970, 1, 1) */
#define POSTGRES_EPOCH_JDATE 2451545 /* == date2j(2000, 1, 1) */
#endif /* DATATYPE_TIMESTAMP_H */
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