int numBytes = isIpv6 ? 16 : 4;

    byte[] addressBytes = address.toByteArray();
    byte[] targetCopyArray = new byte[numBytes];

    int srcPos = Math.max(0, addressBytes.length - numBytes);
    int copyLength = addressBytes.length - srcPos;
    int destPos = numBytes - copyLength;

    // Check the extra bytes in the BigInteger are all zero.