Fix the various forms of AT TIME ZONE to accept either timezones found

in the zic database or zone names found in the date token table.  This
preserves the old ability to do AT TIME ZONE 'PST' along with the new
ability to do AT TIME ZONE 'PST8PDT'.  Per gripe from Bricklen Anderson.
Also, fix some inconsistencies in usage of TZ_STRLEN_MAX --- the old
code had the potential for one-byte buffer overruns, though given
alignment considerations it's unlikely there was any real risk.

1 files changed, 90 insertions, 52 deletions

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 2b15e64e061..b2d6f774c2f 100644
--- 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 1.151 2005/08/25 05:01:43 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.152 2005/09/09 02:31:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1014,7 +1014,7 @@ dt2time(Timestamp jd, int *hour, int *min, int *sec, fsec_t *fsec)
  *	 0 on success
  *	-1 on out of range
  *
- * If attimezone is NULL, the global timezone (including possblly brute forced
+ * If attimezone is NULL, the global timezone (including possibly brute forced
  * timezone) will be used.
  */
 int
@@ -1113,8 +1113,8 @@ timestamp2tm(Timestamp dt, int *tzp, struct pg_tm *tm, fsec_t *fsec, char **tzn,
 	utime = (pg_time_t) dt;
 	if ((Timestamp) utime == dt)
 	{
-		struct pg_tm *tx = pg_localtime(&utime, (attimezone != NULL) ?
-										attimezone : global_timezone);
+		struct pg_tm *tx = pg_localtime(&utime,
+										attimezone ? attimezone : global_timezone);
 
 		tm->tm_year = tx->tm_year + 1900;
 		tm->tm_mon = tx->tm_mon + 1;
@@ -3948,48 +3948,64 @@ Datum
 timestamp_zone(PG_FUNCTION_ARGS)
 {
 	text	   *zone = PG_GETARG_TEXT_P(0);
-	Timestamp timestamp = PG_GETARG_TIMESTAMP(1);
+	Timestamp	timestamp = PG_GETARG_TIMESTAMP(1);
 	TimestampTz	result;
 	int			tz;
 	pg_tz      *tzp;
-	char        tzname[TZ_STRLEN_MAX+1];
+	char        tzname[TZ_STRLEN_MAX + 1];
 	int         len;
-	struct pg_tm tm;
-	fsec_t      fsec;
-	bool		fail;
 	
 	if (TIMESTAMP_NOT_FINITE(timestamp))
 		PG_RETURN_TIMESTAMPTZ(timestamp);
 
-	/* Find the specified timezone */
-	len = (VARSIZE(zone) - VARHDRSZ>TZ_STRLEN_MAX) ?
-			TZ_STRLEN_MAX : VARSIZE(zone) - VARHDRSZ;
+	/*
+	 * Look up the requested timezone.  First we look in the timezone
+	 * database (to handle cases like "America/New_York"), and if that
+	 * fails, we look in the date token table (to handle cases like "EST").
+	 */ 
+	len = Min(VARSIZE(zone) - VARHDRSZ, TZ_STRLEN_MAX);
 	memcpy(tzname, VARDATA(zone), len);
-	tzname[len] = 0;
+	tzname[len] = '\0';
 	tzp = pg_tzset(tzname);
-	if (!tzp)
+	if (tzp)
 	{
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("time zone \"%s\" not recognised",
-				        tzname)));
-		PG_RETURN_NULL();
-	}
+		/* Apply the timezone change */
+		struct pg_tm tm;
+		fsec_t      fsec;
 
-	/* Apply the timezone change */
-	fail = (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, tzp) != 0);
-	if (!fail)
-	{
+		if (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, tzp) != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+					 errmsg("timestamp out of range")));
 		tz = DetermineTimeZoneOffset(&tm, tzp);
-		fail = (tm2timestamp(&tm, fsec, &tz, &result) != 0);
+		if (tm2timestamp(&tm, fsec, &tz, &result) != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("could not convert to time zone \"%s\"",
+							tzname)));
 	}
-	if (fail)
+	else
 	{
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("could not convert to time zone \"%s\"",
-				        tzname)));
-		PG_RETURN_NULL();
+		char	   *lowzone;
+		int			type,
+					val;
+
+		lowzone = downcase_truncate_identifier(VARDATA(zone),
+											   VARSIZE(zone) - VARHDRSZ,
+											   false);
+		type = DecodeSpecial(0, lowzone, &val);
+
+		if (type == TZ || type == DTZ)
+			tz = -(val * 60);
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("time zone \"%s\" not recognized", tzname)));
+			tz = 0;				/* keep compiler quiet */
+		}
+
+		result = dt2local(timestamp, tz);
 	}
 
 	PG_RETURN_TIMESTAMPTZ(result);
@@ -4109,37 +4125,59 @@ timestamptz_zone(PG_FUNCTION_ARGS)
 	Timestamp	result;
 	int			tz;
 	pg_tz	   *tzp;
-	char        tzname[TZ_STRLEN_MAX];
+	char        tzname[TZ_STRLEN_MAX + 1];
 	int         len;
-	struct pg_tm tm;
-	fsec_t      fsec = 0;
 
 	if (TIMESTAMP_NOT_FINITE(timestamp))
-		PG_RETURN_NULL();
+		PG_RETURN_TIMESTAMP(timestamp);
 
-	/* Find the specified zone */
-	len = (VARSIZE(zone) - VARHDRSZ > TZ_STRLEN_MAX) ?
-			TZ_STRLEN_MAX : VARSIZE(zone) - VARHDRSZ;
+	/*
+	 * Look up the requested timezone.  First we look in the timezone
+	 * database (to handle cases like "America/New_York"), and if that
+	 * fails, we look in the date token table (to handle cases like "EST").
+	 */ 
+	len = Min(VARSIZE(zone) - VARHDRSZ, TZ_STRLEN_MAX);
 	memcpy(tzname, VARDATA(zone), len);
-	tzname[len] = 0;
+	tzname[len] = '\0';
 	tzp = pg_tzset(tzname);
-
-	if (!tzp)
+	if (tzp)
 	{
-		ereport(ERROR,
-			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-			 errmsg("time zone \"%s\" not recognized", tzname)));
+		/* Apply the timezone change */
+		struct pg_tm tm;
+		fsec_t      fsec;
 
-		PG_RETURN_NULL();
+		if (timestamp2tm(timestamp, &tz, &tm, &fsec, NULL, tzp) != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+					 errmsg("timestamp out of range")));
+		if (tm2timestamp(&tm, fsec, NULL, &result) != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("could not convert to time zone \"%s\"",
+							tzname)));
 	}
+	else
+	{
+		char	   *lowzone;
+		int			type,
+					val;
 
-	if (timestamp2tm(timestamp, &tz, &tm, &fsec, NULL, tzp) != 0 ||
-	    tm2timestamp(&tm, fsec, NULL, &result))
-	{ 
-		ereport(ERROR,
-			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-			errmsg("could not to convert to time zone \"%s\"", tzname)));
-		PG_RETURN_NULL();
+		lowzone = downcase_truncate_identifier(VARDATA(zone),
+											   VARSIZE(zone) - VARHDRSZ,
+											   false);
+		type = DecodeSpecial(0, lowzone, &val);
+
+		if (type == TZ || type == DTZ)
+			tz = val * 60;
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("time zone \"%s\" not recognized", tzname)));
+			tz = 0;				/* keep compiler quiet */
+		}
+
+		result = dt2local(timestamp, tz);
 	}
 
 	PG_RETURN_TIMESTAMP(result);