Fix to_char for 1 BC. Previously it returned 1 AD.

bmomjian · bmomjian · commit fd071bd478f4 · 2004-03-30T15:53:18.000Z
Fix to_char(year) for BC dates.  Previously it returned one less than
the current year.

Add documentation mentioning that there is no 0 AD.
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.195 2004/03/19 19:13:26 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.196 2004/03/30 15:53:18 momjian Exp $
 PostgreSQL documentation
 -->
 
@@ -5216,8 +5216,7 @@ SELECT EXTRACT(SECOND FROM TIME '17:12:28.5');
       <term><literal>week</literal></term>
       <listitem>
        <para>
-        The number of
-        the week of the year that the day is in.  By definition
+        The number of the week of the year that the day is in.  By definition
         (<acronym>ISO</acronym> 8601), the first week of a year
         contains January 4 of that year.  (The <acronym>ISO</acronym>-8601
         week starts on Monday.)  In other words, the first Thursday of
@@ -5235,7 +5234,8 @@ SELECT EXTRACT(WEEK FROM TIMESTAMP '2001-02-16 20:38:40');
       <term><literal>year</literal></term>
       <listitem>
        <para>
-        The year field
+        The year field.  Keep in mind there is no <literal>0 AD</>, so subtracting 
+        <literal>BC</> years from <literal>AD</> years should be done with care.
        </para>
 
 <screen>
diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.125 2004/02/25 19:41:23 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.126 2004/03/30 15:53:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -93,7 +93,7 @@ static datetkn datetktbl[] = {
 	{"acsst", DTZ, POS(42)},	/* Cent. Australia */
 	{"acst", DTZ, NEG(16)},		/* Atlantic/Porto Acre Summer Time */
 	{"act", TZ, NEG(20)},		/* Atlantic/Porto Acre Time */
-	{DA_D, ADBC, AD},			/* "ad" for years >= 0 */
+	{DA_D, ADBC, AD},			/* "ad" for years > 0 */
 	{"adt", DTZ, NEG(12)},		/* Atlantic Daylight Time */
 	{"aesst", DTZ, POS(44)},	/* E. Australia */
 	{"aest", TZ, POS(40)},		/* Australia Eastern Std Time */
@@ -139,7 +139,7 @@ static datetkn datetktbl[] = {
 	{"azot", TZ, NEG(4)},		/* Azores Time */
 	{"azst", DTZ, POS(20)},		/* Azerbaijan Summer Time */
 	{"azt", TZ, POS(16)},		/* Azerbaijan Time */
-	{DB_C, ADBC, BC},			/* "bc" for years < 0 */
+	{DB_C, ADBC, BC},			/* "bc" for years <= 0 */
 	{"bdst", TZ, POS(8)},		/* British Double Summer Time */
 	{"bdt", TZ, POS(24)},		/* Dacca */
 	{"bnt", TZ, POS(32)},		/* Brunei Darussalam Time */
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------
  * formatting.c
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.72 2004/01/07 18:56:28 neilc Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.73 2004/03/30 15:53:18 momjian Exp $
  *
  *
  *	 Portions Copyright (c) 1999-2003, PostgreSQL Global Development Group
@@ -169,7 +169,7 @@ static char *months_full[] = {
  * AC / DC
  * ----------
  */
-#define YEAR_ABS(_y)	(_y < 0 ? -(_y -1) : _y)
+#define YEAR_ABS(_y)	(_y <= 0 ? -(_y -1) : _y)
 #define BC_STR_ORIG " BC"
 
 #define A_D_STR		"A.D."
@@ -2119,7 +2119,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 		case DCH_B_C:
 			if (flag == TO_CHAR)
 			{
-				strcpy(inout, (tm->tm_year < 0 ? B_C_STR : A_D_STR));
+				strcpy(inout, (tm->tm_year <= 0 ? B_C_STR : A_D_STR));
 				return 3;
 
 			}
@@ -2134,7 +2134,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 		case DCH_BC:
 			if (flag == TO_CHAR)
 			{
-				strcpy(inout, (tm->tm_year < 0 ? BC_STR : AD_STR));
+				strcpy(inout, (tm->tm_year <= 0 ? BC_STR : AD_STR));
 				return 1;
 
 			}
@@ -2149,7 +2149,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 		case DCH_b_c:
 			if (flag == TO_CHAR)
 			{
-				strcpy(inout, (tm->tm_year < 0 ? b_c_STR : a_d_STR));
+				strcpy(inout, (tm->tm_year <= 0 ? b_c_STR : a_d_STR));
 				return 3;
 
 			}
@@ -2164,7 +2164,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 		case DCH_bc:
 			if (flag == TO_CHAR)
 			{
-				strcpy(inout, (tm->tm_year < 0 ? bc_STR : ad_STR));
+				strcpy(inout, (tm->tm_year <= 0 ? bc_STR : ad_STR));
 				return 1;
 
 			}
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.102 2004/03/22 01:38:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.103 2004/03/30 15:53:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3261,7 +3261,11 @@ timestamp_part(PG_FUNCTION_ARGS)
 				break;
 
 			case DTK_YEAR:
-				result = tm->tm_year;
+				if (tm->tm_year > 0)
+					result = tm->tm_year;
+				else
+					/* there is no year 0, just 1 BC and 1 AD*/
+					result = tm->tm_year - 1;	
 				break;
 
 			case DTK_DECADE:

Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,7 @@`
`1`	`1`	`/* -----------------------------------------------------------------------`
`2`	`2`	`* formatting.c`
`3`	`3`	`*`
`4`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.72 2004/01/07 18:56:28 neilc Exp $`
	`4`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.73 2004/03/30 15:53:18 momjian Exp $`
`5`	`5`	`*`
`6`	`6`	`*`
`7`	`7`	`* Portions Copyright (c) 1999-2003, PostgreSQL Global Development Group`
`@@ -169,7 +169,7 @@ static char *months_full[] = {`
`169`	`169`	`* AC / DC`
`170`	`170`	`* ----------`
`171`	`171`	`*/`
`172`		`-#define YEAR_ABS(_y) (_y < 0 ? -(_y -1) : _y)`
	`172`	`+#define YEAR_ABS(_y) (_y <= 0 ? -(_y -1) : _y)`
`173`	`173`	`#define BC_STR_ORIG " BC"`
`174`	`174`
`175`	`175`	`#define A_D_STR "A.D."`
`@@ -2119,7 +2119,7 @@ dch_date(int arg, char inout, int suf, int flag, FormatNode node, void *data)`
`2119`	`2119`	`case DCH_B_C:`
`2120`	`2120`	`if (flag == TO_CHAR)`
`2121`	`2121`	`{`
`2122`		`- strcpy(inout, (tm->tm_year < 0 ? B_C_STR : A_D_STR));`
	`2122`	`+ strcpy(inout, (tm->tm_year <= 0 ? B_C_STR : A_D_STR));`
`2123`	`2123`	`return 3;`
`2124`	`2124`
`2125`	`2125`	`}`
`@@ -2134,7 +2134,7 @@ dch_date(int arg, char inout, int suf, int flag, FormatNode node, void *data)`
`2134`	`2134`	`case DCH_BC:`
`2135`	`2135`	`if (flag == TO_CHAR)`
`2136`	`2136`	`{`
`2137`		`- strcpy(inout, (tm->tm_year < 0 ? BC_STR : AD_STR));`
	`2137`	`+ strcpy(inout, (tm->tm_year <= 0 ? BC_STR : AD_STR));`
`2138`	`2138`	`return 1;`
`2139`	`2139`
`2140`	`2140`	`}`
`@@ -2149,7 +2149,7 @@ dch_date(int arg, char inout, int suf, int flag, FormatNode node, void *data)`
`2149`	`2149`	`case DCH_b_c:`
`2150`	`2150`	`if (flag == TO_CHAR)`
`2151`	`2151`	`{`
`2152`		`- strcpy(inout, (tm->tm_year < 0 ? b_c_STR : a_d_STR));`
	`2152`	`+ strcpy(inout, (tm->tm_year <= 0 ? b_c_STR : a_d_STR));`
`2153`	`2153`	`return 3;`
`2154`	`2154`
`2155`	`2155`	`}`
`@@ -2164,7 +2164,7 @@ dch_date(int arg, char inout, int suf, int flag, FormatNode node, void *data)`
`2164`	`2164`	`case DCH_bc:`
`2165`	`2165`	`if (flag == TO_CHAR)`
`2166`	`2166`	`{`
`2167`		`- strcpy(inout, (tm->tm_year < 0 ? bc_STR : ad_STR));`
	`2167`	`+ strcpy(inout, (tm->tm_year <= 0 ? bc_STR : ad_STR));`
`2168`	`2168`	`return 1;`
`2169`	`2169`
`2170`	`2170`	`}`
Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.102 2004/03/22 01:38:17 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.103 2004/03/30 15:53:18 momjian Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -3261,7 +3261,11 @@ timestamp_part(PG_FUNCTION_ARGS)`
`3261`	`3261`	`break;`
`3262`	`3262`
`3263`	`3263`	`case DTK_YEAR:`
`3264`		`- result = tm->tm_year;`
	`3264`	`+ if (tm->tm_year > 0)`
	`3265`	`+ result = tm->tm_year;`
	`3266`	`+ else`
	`3267`	`+ /* there is no year 0, just 1 BC and 1 AD*/`
	`3268`	`+ result = tm->tm_year - 1;`
`3265`	`3269`	`break;`
`3266`	`3270`
`3267`	`3271`	`case DTK_DECADE:`