/**
* Returns the timestamp for first day of the year for the given date.
*
* @param timestamp
* @return timestamp
*/
public static function firstDayOfYear($ts = null)
{
// default to now
if ($ts === null) {
$ts = sfDateTimeToolkit::now();
}
return sfTime::subtractMonth(sfTime::firstDayOfMonth($ts), date('m', $ts) - 1);
}
