TimeStamp methods + receive date + add days to date

//set these functions in a class : else remove the public hint.
public function getDate($length = 0){
    $date = new DateTime(date("Y")."-".date("m")."-".date("d"));
    $length = ($length == null || !(is_int($length))) ? 0 : $length;
    $date = $date->add(new DateInterval('P'.$length.'D'));
    return $date->format('d-m-Y');
}

public function convertToTimestamp($date){
    $date = explode('-', $date);
    $timestamp = mktime(0, 0, 0, $date[1], $date[0], $date[2]);
    return $timestamp;
}

public function convertToDate($timestamp){
    $date = date('d-m-Y', $timestamp);
    return $date;
}

//usage:

convertToTimestamp(getDate(30)); //get's converted current date with 30 days added

convertToDate($timestamp); //return the date from the timestamp using day-month-year