DNS_import improvement

Good afternoon; this is my first post. When I used the dns import process, I obtain some errors when the TTL field is specified in a non-numeric format (4h, 1d, ...)

The following function (in file ispconfig/interface/web/dns/dns_import.php ) solve this issue (if it's used in the right if/switch):

//ASIG funcion is_numericTTL
// $fff is the evaluated string
// Function result return: true is the $fff argument is a TTL number; false in other case.
// $numttl (by reference) the numeric value of the $fff string (if the argument is a TTL number); else -1
function is_numericTTL($fff, &$numttl) {
$time_format = strtolower(substr($fff, -1));
switch ($time_format) {
case 's':
$numttl = (int)(substr($fff, 0, -1));
break;
case 'm':
$numttl = (int)(substr($fff, 0, -1) * 60);
break;
case 'h':
$numttl = (int)(substr($fff, 0, -1) * 3600);
break;
case 'd':
$numttl = (int)(substr($fff, 0, -1) * 86400);
break;
case 'w':
$numttl = (int)(substr($fff, 0, -1) * 604800);
break;
default:
if (is_numeric($fff)) {
$numttl = (int)$fff;
} else {
$numttl = -1; }
}
return ($numttl != -1);
}