public function getDelta(): IP
    {
        if ($this->delta === null) {
            if ($this->prefix == 0) {
                $this->delta = new static::$ip_class(static::$ip_class::MAX_INT);
            } else {
                $this->delta = new static::$ip_class(gmp_sub(gmp_shiftl(1, static::$ip_class::NB_BITS - $this->prefix), 1));
            }
        }

        return $this->delta;
    }
public function getDelta(): IP
    {
        if ($this->delta === null) {
            if ($this->prefix == 0) {
                $this->delta = new static::$ip_class(static::$ip_class::MAX_INT);
            } else {
                $this->delta = new static::$ip_class(gmp_sub(gmp_shiftl(1, static::$ip_class::NB_BITS - $this->prefix), 1));
            }
        }

        return $this->delta;
    }
public function getDelta ( ) : IP { if ( $ this -> delta === null ) { if ( $ this -> prefix == 0 ) { $ this -> delta = new static :: $ ip_class ( static :: $ ip_class :: MAX_INT ) ; } else { $ this -> delta = new static :: $ ip_class ( gmp_sub ( gmp_shiftl ( 1 , static :: $ ip_class :: NB_BITS - $ this -> prefix ) , 1 ) ) ; } } return $ this -> delta ; }
Return delta to last IP address.

@return IP
Return delta to last IP address .