Patch to extend range of timestamps

Greetings once again,

The following patches eliminate the overflows in the j2date() and date2j()
functions which limited the maximum date for a timestamp to AD 1465001.
The new limit is AD 5874897.
The files affected are:

doc/src/sgml/datatype.sgml:
Documentation change due to patch. Included is a notice about
the reduced range when using an eight-byte integer for timestamps.

src/backend/utils/adt/datetime.c:
Replacement functions for j2date() and date2j() functions.

src/include/utils/datetime.h:
Corrected a bug with the limit on the earliest possible date,
Nov 23,-4713 has a Julian day count of -1. The earliest possible
date should be Nov 24, -4713 with a day count of 0.

src/test/regress/expected/horology-no-DST-before-1970.out:
src/test/regress/expected/horology-solaris-1947.out:
src/test/regress/expected/horology.out:
Copies of expected output for regression testing.
Note: Only horology.out has been physically tested. I do not have access
to a Solaris box and I don't know how to provoke the "pre-1970" test.

src/test/regress/sql/horology.sql:
Added some test cases to check extended range.

---- CUT HERE ----

Index: doc/src/sgml/datatype.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/datatype.sgml,v
retrieving revision 1.113
diff -c -r1.113 datatype.sgml
*** doc/src/sgml/datatype.sgml 2003/01/31 01:08:07 1.113
--- doc/src/sgml/datatype.sgml 2003/02/06 01:27:00
***************
*** 1243,1249 ****
<entry>both date and time</entry>
<entry>8 bytes</entry>
<entry>4713 BC</entry>
! <entry>AD 1465001</entry>
<entry>1 microsecond / 14 digits</entry>
</row>
<row>
--- 1243,1249 ----
<entry>both date and time</entry>
<entry>8 bytes</entry>
<entry>4713 BC</entry>
! <entry>AD 5874897</entry>
<entry>1 microsecond / 14 digits</entry>
</row>
<row>
***************
*** 1251,1257 ****
<entry>both date and time</entry>
<entry>8 bytes</entry>
<entry>4713 BC</entry>
! <entry>AD 1465001</entry>
<entry>1 microsecond / 14 digits</entry>
</row>
<row>
--- 1251,1257 ----
<entry>both date and time</entry>
<entry>8 bytes</entry>
<entry>4713 BC</entry>
! <entry>AD 5874897</entry>
<entry>1 microsecond / 14 digits</entry>
</row>
<row>
***************
*** 1309,1315 ****
a few years of 2000-01-01, but the precision degrades for dates further
away. When timestamps are stored as eight-byte integers (a compile-time
option), microsecond precision is available over the full range of
! values.
</para>
</note>

--- 1309,1316 ----
a few years of 2000-01-01, but the precision degrades for dates further
away. When timestamps are stored as eight-byte integers (a compile-time
option), microsecond precision is available over the full range of
! values. However eight-byte integer timestamps have a reduced range of
! dates from 4713 BC up to 294276 AD.
</para>
</note>

Index: src/backend/utils/adt/datetime.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/adt/datetime.c,v
retrieving revision 1.99
diff -c -r1.99 datetime.c
*** src/backend/utils/adt/datetime.c 2003/01/29 01:08:42 1.99
--- src/backend/utils/adt/datetime.c 2003/02/06 01:27:30
***************
*** 587,652 ****
* since it is numerically accurate and computationally simple.
* The algorithms here will accurately convert between Julian day
* and calendar date for all non-negative Julian days
! * (i.e. from Nov 23, -4713 on).
*
- * Ref: Explanatory Supplement to the Astronomical Almanac, 1992.
- * University Science Books, 20 Edgehill Rd. Mill Valley CA 94941.
- *
- * Use the algorithm by Henry Fliegel, a former NASA/JPL colleague
- * now at Aerospace Corp. (hi, Henry!)
- *
* These routines will be used by other date/time packages
* - thomas 97/02/25
*/

int
date2j(int y, int m, int d)
{
! int m12 = (m - 14) / 12;

! return ((1461 * (y + 4800 + m12)) / 4
! + (367 * (m - 2 - 12 * (m12))) / 12
! - (3 * ((y + 4900 + m12) / 100)) / 4
! + d - 32075);
} /* date2j() */

void
j2date(int jd, int *year, int *month, int *day)
{
! int j,
! y,
! m,
! d;
!
! int i,
! l,
! n;
!
! l = jd + 68569;
! n = (4 * l) / 146097;
! l -= (146097 * n + 3) / 4;
! i = (4000 * (l + 1)) / 1461001;
! l += 31 - (1461 * i) / 4;
! j = (80 * l) / 2447;
! d = l - (2447 * j) / 80;
! l = j / 11;
! m = (j + 2) - (12 * l);
! y = 100 * (n - 49) + i + l;
!
! *year = y;
! *month = m;
! *day = d;
return;
} /* j2date() */

int
j2day(int date)
{
! int day;

! day = (date + 1) % 7;

! return day;
} /* j2day() */


--- 587,663 ----
* since it is numerically accurate and computationally simple.
* The algorithms here will accurately convert between Julian day
* and calendar date for all non-negative Julian days
! * (i.e. from Nov 24, -4713 on).
*
* These routines will be used by other date/time packages
* - thomas 97/02/25
+ *
+ * Rewritten to eliminate overflow problems. This now allows the
+ * routines to work correctly for all Julian day counts from
+ * 0 to 2147483647 (Nov 24, -4713 to Jun 3, 5874898) assuming
+ * a 32-bit integer. Longer types should also work to the limits
+ * of their precision.
*/

int
date2j(int y, int m, int d)
{
! int julian;
! int century;

! if (m > 2) {
! m += 1;
! y += 4800;
! } else {
! m += 13;
! y += 4799;
! }
!
! century = y/100;
! julian = y*365 - 32167;
! julian += y/4 - century + century/4;
! julian += 7834*m/256 + d;
!
! return julian;
} /* date2j() */

void
j2date(int jd, int *year, int *month, int *day)
{
! unsigned int julian;
! unsigned int quad;
! unsigned int extra;
! int y;
!
! julian = jd;
! julian += 32044;
! quad = julian/146097;
! extra = (julian - quad*146097)*4 + 3;
! julian += 60 + quad*3 + extra/146097;
! quad = julian/1461;
! julian -= quad*1461;
! y = julian * 4 / 1461;
! julian = ((y != 0) ? ((julian + 305) % 365) : ((julian + 306) % 366))
! + 123;
! y += quad*4;
! *year = y - 4800;
! quad = julian * 2141 / 65536;
! *day = julian - 7834*quad/256;
! *month = (quad + 10) % 12 + 1;
!
return;
} /* j2date() */

int
j2day(int date)
{
! unsigned int day;

! day = date;
! day += 1;
! day %= 7;

! return (int) day;
} /* j2day() */


Index: src/include/utils/datetime.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/utils/datetime.h,v
retrieving revision 1.34
diff -c -r1.34 datetime.h
*** src/include/utils/datetime.h 2003/01/16 00:26:49 1.34
--- src/include/utils/datetime.h 2003/02/06 01:27:44
***************
*** 239,245 ****

#define JULIAN_MINYEAR (-4713)
#define JULIAN_MINMONTH (11)
! #define JULIAN_MINDAY (23)

#define IS_VALID_JULIAN(y,m,d) (((y) > JULIAN_MINYEAR) \
|| (((y) == JULIAN_MINYEAR) && (((m) > JULIAN_MINMONTH) \
--- 239,245 ----

#define JULIAN_MINYEAR (-4713)
#define JULIAN_MINMONTH (11)
! #define JULIAN_MINDAY (24)

#define IS_VALID_JULIAN(y,m,d) (((y) > JULIAN_MINYEAR) \
|| (((y) == JULIAN_MINYEAR) && (((m) > JULIAN_MINMONTH) \
Index: src/test/regress/expected/horology-no-DST-before-1970.out
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/test/regress/expected/horology-no-DST-before-1970.out,v
retrieving revision 1.27
diff -c -r1.27 horology-no-DST-before-1970.out
*** src/test/regress/expected/horology-no-DST-before-1970.out 2003/01/31 01:08:08 1.27
--- src/test/regress/expected/horology-no-DST-before-1970.out 2003/02/06 01:28:17
***************
*** 328,333 ****
--- 328,357 ----
Fri Dec 31 23:59:59 1999
(1 row)

+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '1000000000 days' AS "Nov 27, 2733194";
+ Nov 27, 2733194
+ -----------------------------
+ Sun Nov 27 00:00:00 2733194
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '2000000000 days' AS "Nov 30, 5471101";
+ Nov 30, 5471101
+ -----------------------------
+ Sat Nov 30 00:00:00 5471101
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 25, 4714 BC' + interval '2147483492 days' AS "Dec 31, 5874897";
+ Dec 31, 5874897
+ -----------------------------
+ Tue Dec 31 00:00:00 5874897
+ (1 row)
+
+ SELECT timestamp without time zone '12/31/5874897' - timestamp without time zone 'Nov 24, 4714 BC' AS "2147483493 Days";
+ 2147483493 Days
+ -------------------
+ @ 2147483493 days
+ (1 row)
+
-- Shorthand values
-- Not directly usable for regression testing since these are not constants.
-- So, just try to test parser and hope for the best - thomas 97/04/26
Index: src/test/regress/expected/horology-solaris-1947.out
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/test/regress/expected/horology-solaris-1947.out,v
retrieving revision 1.21
diff -c -r1.21 horology-solaris-1947.out
*** src/test/regress/expected/horology-solaris-1947.out 2003/01/31 01:08:08 1.21
--- src/test/regress/expected/horology-solaris-1947.out 2003/02/06 01:28:34
***************
*** 328,333 ****
--- 328,357 ----
Fri Dec 31 23:59:59 1999
(1 row)

+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '1000000000 days' AS "Nov 27, 2733194";
+ Nov 27, 2733194
+ -----------------------------
+ Sun Nov 27 00:00:00 2733194
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '2000000000 days' AS "Nov 30, 5471101";
+ Nov 30, 5471101
+ -----------------------------
+ Sat Nov 30 00:00:00 5471101
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 25, 4714 BC' + interval '2147483492 days' AS "Dec 31, 5874897";
+ Dec 31, 5874897
+ -----------------------------
+ Tue Dec 31 00:00:00 5874897
+ (1 row)
+
+ SELECT timestamp without time zone '12/31/5874897' - timestamp without time zone 'Nov 24, 4714 BC' AS "2147483493 Days";
+ 2147483493 Days
+ -------------------
+ @ 2147483493 days
+ (1 row)
+
-- Shorthand values
-- Not directly usable for regression testing since these are not constants.
-- So, just try to test parser and hope for the best - thomas 97/04/26
Index: src/test/regress/expected/horology.out
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/test/regress/expected/horology.out,v
retrieving revision 1.40
diff -c -r1.40 horology.out
*** src/test/regress/expected/horology.out 2003/01/31 01:08:08 1.40
--- src/test/regress/expected/horology.out 2003/02/06 01:28:56
***************
*** 328,333 ****
--- 328,357 ----
Fri Dec 31 23:59:59 1999
(1 row)

+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '1000000000 days' AS "Nov 27, 2733194";
+ Nov 27, 2733194
+ -----------------------------
+ Sun Nov 27 00:00:00 2733194
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '2000000000 days' AS "Nov 30, 5471101";
+ Nov 30, 5471101
+ -----------------------------
+ Sat Nov 30 00:00:00 5471101
+ (1 row)
+
+ SELECT timestamp without time zone 'Nov 25, 4714 BC' + interval '2147483492 days' AS "Dec 31, 5874897";
+ Dec 31, 5874897
+ -----------------------------
+ Tue Dec 31 00:00:00 5874897
+ (1 row)
+
+ SELECT timestamp without time zone '12/31/5874897' - timestamp without time zone 'Nov 24, 4714 BC' AS "2147483493 Days";
+ 2147483493 Days
+ -------------------
+ @ 2147483493 days
+ (1 row)
+
-- Shorthand values
-- Not directly usable for regression testing since these are not constants.
-- So, just try to test parser and hope for the best - thomas 97/04/26
Index: src/test/regress/sql/horology.sql
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/test/regress/sql/horology.sql,v
retrieving revision 1.25
diff -c -r1.25 horology.sql
*** src/test/regress/sql/horology.sql 2003/01/31 01:08:08 1.25
--- src/test/regress/sql/horology.sql 2003/02/06 01:28:58
***************
*** 76,81 ****
--- 76,85 ----
SELECT timestamp without time zone '1999-03-01' - interval '1 second' AS "Feb 28";
SELECT timestamp without time zone '2000-03-01' - interval '1 second' AS "Feb 29";
SELECT timestamp without time zone '1999-12-01' + interval '1 month - 1 second' AS "Dec 31";
+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '1000000000 days' AS "Nov 27, 2733194";
+ SELECT timestamp without time zone 'Nov 24, 4714 BC' + interval '2000000000 days' AS "Nov 30, 5471101";
+ SELECT timestamp without time zone 'Nov 25, 4714 BC' + interval '2147483492 days' AS "Dec 31, 5874897";
+ SELECT timestamp without time zone '12/31/5874897' - timestamp without time zone 'Nov 24, 4714 BC' AS "2147483493 Days";

-- Shorthand values
-- Not directly usable for regression testing since these are not constants.