TimeHelper::getTimestampByUserDate

public function getTimestampByUserDate($formattedDate, $userId, $format = null)
{
	$dateFormat = $this->getDateFormat();
	if ($format !== null)
	{
		$dateFormat = $format;
	}

	$ts = $this->buildTimestampByFormattedDateForServer($formattedDate, $dateFormat);
	return $ts > 0 ? $ts - $this->getUserToServerOffset($userId) : null;
}