/**
* Returns the normalized (Olson) timezone name of a timezone alias.
*
* We currently support Windows and Lotus timezone names, and timezone
* abbreviations.
*
* @since Horde_Date 2.3.0
*
* @param string $timezone Some timezone alias.
*
* @return string The Olson timezone name, or the original value, if no
* alias found.
*/
public static function getTimezoneAlias($timezone)
{
if (empty(self::$_timezoneIdentifiers)) {
self::$_timezoneIdentifiers = array_flip(DateTimeZone::listIdentifiers());
}
if (isset(self::$_timezoneIdentifiers[$timezone])) {
return $timezone;
}
/* Workaround for standard cases of bug #11688 */
if (isset(self::$_timezoneAliases[$timezone])) {
$timezone = self::$_timezoneAliases[$timezone];
}
if (empty(self::$_timezoneAbbreviations)) {
self::$_timezoneAbbreviations = DateTimeZone::listAbbreviations();
}
$lower = Horde_String::lower($timezone);
if (isset(self::$_timezoneAbbreviations[$lower])) {
$timezone = reset(self::$_timezoneAbbreviations[$lower]);
$timezone = $timezone['timezone_id'];
}
return $timezone;
}