From bb2bff498cb453726da5fc95bdc169bd879ae311 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 2 Jan 2002 22:09:23 +0000
Subject: [PATCH] Fix to_timestamp/to_date so that zero year input for Y, YY,
 or YYY formats will be taken as 2000, not year zero.  Per bug report from
 Aasmund Midttun Godal.  Fix from Karel Zak.

---
 src/backend/utils/adt/formatting.c | 97 +++++++++++++-----------------
 1 file changed, 41 insertions(+), 56 deletions(-)

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index e5ac6c7751..5970cde8ca 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------
  * formatting.c
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.47 2001/12/10 15:34:05 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.48 2002/01/02 22:09:23 tgl Exp $
  *
  *
  *	 Portions Copyright (c) 1999-2000, PostgreSQL Global Development Group
@@ -371,10 +371,7 @@ typedef struct
 				ddd,
 				mm,
 				ms,
-				yyyy,
-				yyy,
-				yy,
-				y,
+				year,
 				bc,
 				iw,
 				ww,
@@ -393,10 +390,10 @@ typedef struct
  */
 #ifdef DEBUG_TO_FROM_CHAR
 #define DEBUG_TMFC( _X ) \
-		elog(DEBUG_elog_output, "TMFC:\nhh %d\nam %d\npm %d\nmi %d\nss %d\nssss %d\nd %d\ndd %d\nddd %d\nmm %d\nms: %d\nyyyy %d\nbc %d\niw %d\nww %d\nw %d\ncc %d\nq %d\nj %d\nus: %d", \
+		elog(DEBUG_elog_output, "TMFC:\nhh %d\nam %d\npm %d\nmi %d\nss %d\nssss %d\nd %d\ndd %d\nddd %d\nmm %d\nms: %d\nyear %d\nbc %d\niw %d\nww %d\nw %d\ncc %d\nq %d\nj %d\nus: %d", \
 			(_X)->hh, (_X)->am, (_X)->pm, (_X)->mi, (_X)->ss, \
 			(_X)->ssss, (_X)->d, (_X)->dd, (_X)->ddd, (_X)->mm, (_X)->ms, \
-			(_X)->yyyy, (_X)->bc, (_X)->iw, (_X)->ww, (_X)->w, \
+			(_X)->year, (_X)->bc, (_X)->iw, (_X)->ww, (_X)->w, \
 			(_X)->cc, (_X)->q, (_X)->j, (_X)->us);
 #define DEBUG_TM( _X ) \
 		elog(DEBUG_elog_output, "TM:\nsec %d\nyear %d\nmin %d\nwday %d\nhour %d\nyday %d\nmday %d\nnisdst %d\nmon %d\n",\
@@ -2396,8 +2393,8 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 			{
 				int			cc;
 
-				sscanf(inout, "%d,%03d", &cc, &tmfc->yyyy);
-				tmfc->yyyy += (cc * 1000);
+				sscanf(inout, "%d,%03d", &cc, &tmfc->year);
+				tmfc->year += (cc * 1000);
 
 				return strdigits_len(inout) + 3 + SKIP_THth(suf);
 			}
@@ -2417,12 +2414,12 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 			{
 				if (S_FM(suf) || is_next_separator(node))
 				{
-					sscanf(inout, "%d", &tmfc->yyyy);
+					sscanf(inout, "%d", &tmfc->year);
 					return strdigits_len(inout) - 1 + SKIP_THth(suf);
 				}
 				else
 				{
-					sscanf(inout, "%04d", &tmfc->yyyy);
+					sscanf(inout, "%04d", &tmfc->year);
 					return 3 + SKIP_THth(suf);
 				}
 			}
@@ -2443,7 +2440,18 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 			}
 			else if (flag == FROM_CHAR)
 			{
-				sscanf(inout, "%03d", &tmfc->yyy);
+				sscanf(inout, "%03d", &tmfc->year);
+				
+				/*
+				 * 3-digit year:
+				 *	'100' ... '999' = 1100 ... 1999
+				 *	'000' ... '099' = 2000 ... 2099
+				 */
+				if (tmfc->year >= 100)
+					tmfc->year += 1000;
+				else
+					tmfc->year += 2000;
+
 				return 2 + SKIP_THth(suf);
 			}
 			break;
@@ -2463,7 +2471,18 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 			}
 			else if (flag == FROM_CHAR)
 			{
-				sscanf(inout, "%02d", &tmfc->yy);
+				sscanf(inout, "%02d", &tmfc->year);
+
+				/*
+				 * 2-digit year:
+				 * '00' ... '69'  = 2000 ... 2069
+				 * '70' ... '99'  = 1970 ... 1999
+		 		 */
+				if (tmfc->year < 70)
+					tmfc->year += 2000;
+				else
+					tmfc->year += 1900;
+
 				return 1 + SKIP_THth(suf);
 			}
 			break;
@@ -2483,7 +2502,13 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
 			}
 			else if (flag == FROM_CHAR)
 			{
-				sscanf(inout, "%1d", &tmfc->y);
+				sscanf(inout, "%1d", &tmfc->year);
+				
+				/*
+				 * 1-digit year: always +2000
+				 */
+				tmfc->year += 2000;
+
 				return 0 + SKIP_THth(suf);
 			}
 			break;
@@ -3002,48 +3027,8 @@ to_timestamp(PG_FUNCTION_ARGS)
 			break;
 	}
 
-	if (tmfc.yyyy)
-		tm.tm_year = tmfc.yyyy;
-
-	else if (tmfc.y)
-	{
-		/*
-		 * 1-digit year: always +2000
-		 */
-		tm.tm_year = tmfc.y + 2000;
-	}
-	else if (tmfc.yy)
-	{
-
-		/*---------
-		 * 2-digit year:
-		 * '00' ... '69'  = 2000 ... 2069
-		 * '70' ... '99'  = 1970 ... 1999
-		 *---------
-		 */
-		tm.tm_year = tmfc.yy;
-
-		if (tm.tm_year < 70)
-			tm.tm_year += 2000;
-		else
-			tm.tm_year += 1900;
-	}
-	else if (tmfc.yyy)
-	{
-
-		/*---------
-		 * 3-digit year:
-		 *	'100' ... '999' = 1100 ... 1999
-		 *	'000' ... '099' = 2000 ... 2099
-		 *---------
-		 */
-		tm.tm_year = tmfc.yyy;
-
-		if (tm.tm_year >= 100)
-			tm.tm_year += 1000;
-		else
-			tm.tm_year += 2000;
-	}
+	if (tmfc.year)
+		tm.tm_year = tmfc.year;
 
 	if (tmfc.bc)
 	{