public long toLong() {
        long t = (long) first << 24 | (long) second << 16 | (long) third << 8 | (long) fourth;
        if (mask == 32) return t;
        else return t - (t % toHostMask());
    }

    public long toHostMask() {
        return (long) 1 << (32 - mask);
    }

    public boolean in(IPAddress address) {
        long thisLong = this.toLong();
        long addressLong = address.toLong();
        return thisLong >= addressLong && thisLong <= (addressLong + address.toHostMask() - 1);
    }