Mine

unset($esctype);if (preg_match_all('/\%([A-Fa-f0-9]{2})/',$_SERVER['QUERY_STRING'], $cmat)) {    foreach($cmat[1] as $c) {        if (!ctype_digit($c)) {            if (strtoupper($c) == $c) {                if (!isset($esctype) || $esctype == 'up')                    $esctype = 'up';                elseif ($esctype == 'low') {                    $esctype = 'mix';                    break;                }            }            elseif (strtolower($c) == $c) {                if (!isset($esctype) || $esctype == 'low')                    $esctype = 'low';                elseif ($esctype == 'up') {                    $esctype = 'mix';                    break;                }            }            else {                $esctype = 'mix';                break;            }        }    }}