return null;
    }
    int partsSkipped = IPV6_PART_COUNT - (delimiterCount + 1); // estimate; may be modified later
    boolean hasSkip = false;
    // Scan for the appearance of ::, to mark a skip-format IPV6 string and adjust the partsSkipped
    // estimate.
    for (int i = 0; i < ipString.length() - 1; i++) {