diff options
Diffstat (limited to 'src/include/datatype/timestamp.h')
| -rw-r--r-- | src/include/datatype/timestamp.h | 79 |
1 files changed, 69 insertions, 10 deletions
diff --git a/src/include/datatype/timestamp.h b/src/include/datatype/timestamp.h index 12a2a8afadb..68a41ebdc51 100644 --- a/src/include/datatype/timestamp.h +++ b/src/include/datatype/timestamp.h @@ -147,27 +147,86 @@ typedef struct /* * 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. + * date2j() and j2date() nominally handle the Julian date range 0..INT_MAX, + * or 4714-11-24 BC to 5874898-06-03 AD. In practice, date2j() will work and + * give correct negative Julian dates for dates before 4714-11-24 BC as well. + * We rely on it to do so back to 4714-11-01 BC. Allowing at least one day's + * slop is necessary so that timestamp rotation doesn't produce dates that + * would be rejected on input. For example, '4714-11-24 00:00 GMT BC' is a + * legal timestamptz value, but in zones east of Greenwich it would print as + * sometime in the afternoon of 4714-11-23 BC; if we couldn't process such a + * date we'd have a dump/reload failure. So the idea is for IS_VALID_JULIAN + * to accept a slightly wider range of dates than we really support, and + * then we apply the exact checks in IS_VALID_DATE or IS_VALID_TIMESTAMP, + * after timezone rotation if any. To save a few cycles, we can make + * IS_VALID_JULIAN check only to the month boundary, since its exact cutoffs + * are not very critical in this scheme. + * + * It is correct that JULIAN_MINYEAR is -4713, not -4714; it is defined to + * allow easy comparison to tm_year values, in which we follow the convention + * that tm_year <= 0 represents abs(tm_year)+1 BC. */ #define JULIAN_MINYEAR (-4713) #define JULIAN_MINMONTH (11) #define JULIAN_MINDAY (24) #define JULIAN_MAXYEAR (5874898) +#define JULIAN_MAXMONTH (6) +#define JULIAN_MAXDAY (3) #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) */ + (((y) > JULIAN_MINYEAR || \ + ((y) == JULIAN_MINYEAR && ((m) >= JULIAN_MINMONTH))) && \ + ((y) < JULIAN_MAXYEAR || \ + ((y) == JULIAN_MAXYEAR && ((m) < JULIAN_MAXMONTH)))) /* 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) */ +/* + * Range limits for dates and timestamps. + * + * We have traditionally allowed Julian day zero as a valid datetime value, + * so that is the lower bound for both dates and timestamps. + * + * The upper limit for dates is 5874897-12-31, which is a bit less than what + * the Julian-date code can allow. We use that same limit for timestamps when + * using floating-point timestamps (so that the timezone offset problem would + * exist here too if there were no slop). For integer timestamps, the upper + * limit is 294276-12-31. The int64 overflow limit would be a few days later; + * again, leaving some slop avoids worries about corner-case overflow, and + * provides a simpler user-visible definition. + */ + +/* First allowed date, and first disallowed date, in Julian-date form */ +#define DATETIME_MIN_JULIAN (0) +#define DATE_END_JULIAN (2147483494) /* == date2j(JULIAN_MAXYEAR, 1, 1) */ +#ifdef HAVE_INT64_TIMESTAMP +#define TIMESTAMP_END_JULIAN (109203528) /* == date2j(294277, 1, 1) */ +#else +#define TIMESTAMP_END_JULIAN DATE_END_JULIAN +#endif + +/* Timestamp limits */ +#ifdef HAVE_INT64_TIMESTAMP +#define MIN_TIMESTAMP INT64CONST(-211813488000000000) +/* == (DATETIME_MIN_JULIAN - POSTGRES_EPOCH_JDATE) * USECS_PER_DAY */ +#define END_TIMESTAMP INT64CONST(9223371331200000000) +/* == (TIMESTAMP_END_JULIAN - POSTGRES_EPOCH_JDATE) * USECS_PER_DAY */ +#else +#define MIN_TIMESTAMP (-211813488000.0) +/* == (DATETIME_MIN_JULIAN - POSTGRES_EPOCH_JDATE) * SECS_PER_DAY */ +#define END_TIMESTAMP 185330760393600.0 +/* == (TIMESTAMP_END_JULIAN - POSTGRES_EPOCH_JDATE) * SECS_PER_DAY */ +#endif + +/* Range-check a date (given in Postgres, not Julian, numbering) */ +#define IS_VALID_DATE(d) \ + ((DATETIME_MIN_JULIAN - POSTGRES_EPOCH_JDATE) <= (d) && \ + (d) < (DATE_END_JULIAN - POSTGRES_EPOCH_JDATE)) + +/* Range-check a timestamp */ +#define IS_VALID_TIMESTAMP(t) (MIN_TIMESTAMP <= (t) && (t) < END_TIMESTAMP) + #endif /* DATATYPE_TIMESTAMP_H */ |