return $sc >= 200 &&
$sc < 300;
}function is_redirect ($sc) { return $sc >= 300 &&
$sc < 400;
}function is_error ($sc) { return $sc >= 400 &&
$sc < 600;
}function is_client_error ($sc) { return $sc >= 400 &&
$sc < 500;
}function is_server_error ($sc) { return $sc >= 500 &&
$sc < 600;
}class RSSCache { var $BASE_CACHE; // where the cache files are stored
var $MAX_AGE = 43200; // when are files stale, default twelve hours
var $ERROR = ''; // accumulate error messages