convert file to utf8

function convert_to_utf8_recursively($dat)
{
    if (is_string($dat)) {
        return mb_convert_encoding($dat, 'UTF-8', 'UTF-8');
    } elseif (is_array($dat)) {
        $ret = array();
        foreach ($dat as $i => $d) $ret[ $i ] = convert_to_utf8_recursively($d);

        return $ret;
    } elseif (is_object($dat)) {
        foreach ($dat as $i => $d) $dat->$i = convert_to_utf8_recursively($d);

        return $dat;
    } else {
        return $dat;
    }
}