From f4898c945fb18c3ced03101adecb6c58e4128ad5 Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Thu, 11 Mar 2010 18:43:24 +0000
Subject: Sync timezone code with tzcode 2010c from the Olson group.  This
 fixes some corner cases that come up in certain timezones (apparently, only
 those with lots and lots of distinct TZ transition rules, as far as I can
 gather from a quick scan of their archives).  Per suggestion from Jeevan
 Chalke.

Back-patch to 8.4.  Possibly we need to push this into earlier releases
as well, but I'm hesitant to update them to the 64-bit tzcode without
more thought and testing.
---
 src/timezone/localtime.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

(limited to 'src/timezone/localtime.c')

diff --git a/src/timezone/localtime.c b/src/timezone/localtime.c
index 869b4462092..da1646c25d9 100644
--- a/src/timezone/localtime.c
+++ b/src/timezone/localtime.c
@@ -3,7 +3,7 @@
  * 1996-06-05 by Arthur David Olson.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.21 2009/06/11 14:49:15 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.22 2010/03/11 18:43:24 tgl Exp $
  */
 
 /*
@@ -164,6 +164,7 @@ tzload(const char *name, char *canonname, struct state * sp, int doextend)
 									4 * TZ_MAX_TIMES];
 	}			u;
 
+	sp->goback = sp->goahead = FALSE;
 	if (name == NULL && (name = TZDEFAULT) == NULL)
 		return -1;
 	if (name[0] == ':')
@@ -357,16 +358,25 @@ tzload(const char *name, char *canonname, struct state * sp, int doextend)
 			sp->ttis[sp->typecnt++] = ts.ttis[1];
 		}
 	}
-	i = 2 * YEARSPERREPEAT;
-	sp->goback = sp->goahead = sp->timecnt > i;
-	sp->goback = sp->goback &&
-		typesequiv(sp, sp->types[i], sp->types[0]) &&
-		differ_by_repeat(sp->ats[i], sp->ats[0]);
-	sp->goahead = sp->goahead &&
-		typesequiv(sp, sp->types[sp->timecnt - 1],
-				   sp->types[sp->timecnt - 1 - i]) &&
-		differ_by_repeat(sp->ats[sp->timecnt - 1],
-						 sp->ats[sp->timecnt - 1 - i]);
+	if (sp->timecnt > 1)
+	{
+		for (i = 1; i < sp->timecnt; ++i)
+			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
+				differ_by_repeat(sp->ats[i], sp->ats[0]))
+			{
+				sp->goback = TRUE;
+				break;
+			}
+		for (i = sp->timecnt - 2; i >= 0; --i)
+			if (typesequiv(sp, sp->types[sp->timecnt - 1],
+						   sp->types[i]) &&
+				differ_by_repeat(sp->ats[sp->timecnt - 1],
+								 sp->ats[i]))
+			{
+				sp->goahead = TRUE;
+				break;
+			}
+	}
 	return 0;
 }
 
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