public func getUInt64 (offset: Int) -> UInt64 {
        let eight = UInt64(data[allowedOffset + offset]) << 56
        let seven = UInt64(data[allowedOffset + offset + 1]) << 48
        let six = UInt64(data[allowedOffset + offset + 2]) << 40
        let five = UInt64(data[allowedOffset + offset + 3]) << 32