std::string Record::IntToIPv6(std::string line)
{
    uint64_t num = 0;
    char* endptr;
    num = strtoll(line.c_str(), &endptr, 10);

    std::ostringstream os;
    os << std::hex << std::setw( 16) << num;
    std::string ret = os.str();
    for (int i = 4; i < 15; i+=4) {
        ret.insert(i++, 1, ':');
    }
    return ret;
}