From ac78c4178bec7b252d22a39515ad6efd6c1a7d7e Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Tue, 7 Aug 2012 13:34:44 -0400
Subject: [PATCH] Fix to_char(), to_date(), and to_timestamp() to handle
negative/BC century specifications just like positive/AD centuries.
Previously the behavior was either wrong or inconsistent with positive/AD
handling.
Centuries without years now always assume the first year of the century,
which is now documented.
---
doc/src/sgml/func.sgml | 4 +-
src/backend/utils/adt/formatting.c | 49 +++++++++++++++--------
src/test/regress/expected/timestamp.out | 4 +-
src/test/regress/expected/timestamptz.out | 4 +-
4 files changed, 39 insertions(+), 22 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index ee42da80257..d5ad4718b15 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -5575,7 +5575,9 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
if there is a <literal>YYY</literal>, <literal>YYYY</literal> or
<literal>Y,YYY</literal> field. If <literal>CC</literal> is used with
<literal>YY</literal> or <literal>Y</literal> then the year is computed
- as <literal>(CC-1)*100+YY</literal>.
+ as the year in the specified century. If the century is
+ specified but the year is not, the first year of the century
+ is assumed.
</para>
</listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 4347ad317fa..ddb89c463bc 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -2640,8 +2640,15 @@ DCH_to_char(FormatNode *node, bool is_interval, TmToChar *in, char *out, Oid col
case DCH_CC:
if (is_interval) /* straight calculation */
i = tm->tm_year / 100;
- else /* century 21 starts in 2001 */
- i = (tm->tm_year - 1) / 100 + 1;
+ else
+ {
+ if (tm->tm_year > 0)
+ /* Century 20 == 1901 - 2000 */
+ i = (tm->tm_year - 1) / 100 + 1;
+ else
+ /* Century 6BC == 600BC - 501BC */
+ i = tm->tm_year / 100 - 1;
+ }
if (i <= 99 && i >= -99)
sprintf(s, "%0*d", S_FM(n->suffix) ? 0 : 2, i);
else
@@ -3465,33 +3472,41 @@ do_to_timestamp(text *date_txt, text *fmt,
/*
* If CC and YY (or Y) are provided, use YY as 2 low-order digits for
* the year in the given century. Keep in mind that the 21st century
- * runs from 2001-2100, not 2000-2099.
- *
- * If a 4-digit year is provided, we use that and ignore CC.
+ * AD runs from 2001-2100, not 2000-2099; 6th century BC runs from
+ * 600BC to 501BC.
*/
if (tmfc.cc && tmfc.yysz <= 2)
{
+ if (tmfc.bc)
+ tmfc.cc = -tmfc.cc;
tm->tm_year = tmfc.year % 100;
if (tm->tm_year)
- tm->tm_year += (tmfc.cc - 1) * 100;
+ {
+ if (tmfc.cc >= 0)
+ tm->tm_year += (tmfc.cc - 1) * 100;
+ else
+ tm->tm_year = (tmfc.cc + 1) * 100 - tm->tm_year + 1;
+ }
else
- tm->tm_year = tmfc.cc * 100;
+ /* find century year for dates ending in "00" */
+ tm->tm_year = tmfc.cc * 100 + ((tmfc.cc >= 0) ? 0 : 1);
}
else
+ /* If a 4-digit year is provided, we use that and ignore CC. */
+ {
tm->tm_year = tmfc.year;
+ if (tmfc.bc && tm->tm_year > 0)
+ tm->tm_year = -(tm->tm_year - 1);
+ }
}
- else if (tmfc.cc) /* use first year of century */
- tm->tm_year = (tmfc.cc - 1) * 100 + 1;
-
- if (tmfc.bc)
+ else if (tmfc.cc) /* use first year of century */
{
- if (tm->tm_year > 0)
- tm->tm_year = -(tm->tm_year - 1);
+ if (tmfc.bc)
+ tmfc.cc = -tmfc.cc;
+ if (tmfc.cc >= 0)
+ tm->tm_year = (tmfc.cc - 1) * 100 + 1;
else
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_DATETIME_FORMAT),
- errmsg("inconsistent use of year %04d and \"BC\"",
- tm->tm_year)));
+ tm->tm_year = tmfc.cc * 100 + 1;
}
if (tmfc.j)
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index ab8faab52e1..db2cfe60333 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -992,7 +992,7 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
| 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
| 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
| 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
- | 0,097 0097 097 97 7 01 1 02 07 047 16 3 1686042
+ | 0,097 0097 097 97 7 -1 1 02 07 047 16 3 1686042
| 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
| 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
| 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
@@ -1063,7 +1063,7 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
| 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
| 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
| 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
- | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042
+ | 0,097 97 97 97 7 -1 1 2 7 47 16 3 1686042
| 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
| 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
| 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index 9a4ce3e3363..6581b5e6a97 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -1074,7 +1074,7 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
| 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
| 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
| 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
- | 0,097 0097 097 97 7 01 1 02 07 047 16 3 1686042
+ | 0,097 0097 097 97 7 -1 1 02 07 047 16 3 1686042
| 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
| 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
| 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
@@ -1146,7 +1146,7 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
| 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
| 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
| 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
- | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042
+ | 0,097 97 97 97 7 -1 1 2 7 47 16 3 1686042
| 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
| 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
| 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778
--
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