datediff in PHP?

[OhMyGod]

tempo fai trovai come open source la funzione DateDiff dell'ASP convertita in PHP per scopi didattici

function datediff($interval, $date1, $date2) {
    $seconds = $date2 - $date1;
    switch ($interval) {
        case "y":    // years
            list($year1, $month1, $day1) = split('-', date('Y-m-d', $date1));
            list($year2, $month2, $day2) = split('-', date('Y-m-d', $date2));
            $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
            $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
            $diff = $year2 - $year1;
            if($month1 > $month2) {
                $diff -= 1;
            } elseif($month1 == $month2) {
                if($day1 > $day2) {
                    $diff -= 1;
                } elseif($day1 == $day2) {
                    if($time1 > $time2) {
                        $diff -= 1;
                    }
                }
            }
            break;
        case "m":    // months
            list($year1, $month1, $day1) = split('-', date('Y-m-d', $date1));
            list($year2, $month2, $day2) = split('-', date('Y-m-d', $date2));
            $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
            $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
            $diff = ($year2 * 12 + $month2) - ($year1 * 12 + $month1);
            if($day1 > $day2) {
                $diff -= 1;
            } elseif($day1 == $day2) {
                if($time1 > $time2) {
                    $diff -= 1;
                }
            }
            break;
       case "w":    // weeks
            // Only simple seconds calculation needed from here on
            $diff = floor($seconds / 604800);
            break;
       case "d":    // days
            $diff = floor($seconds / 86400);
            break;
       case "h":    // hours
            $diff = floor($seconds / 3600);
            break;
       case "i":    // minutes
            $diff = floor($seconds / 60);
            break;
       case "s":    // seconds
            $diff = $seconds;
            break;
    }
    return $diff;
}