Method resolve

src/SFML/Network/Dns.cpp:438–564

///////////////////////////////////////////////////////

{
////////////////////////////////////////////////////////////
std::optional<std::vector<IpAddress>> Dns::resolve(const String&                 hostname,
                                                   const std::vector<IpAddress>& servers,
                                                   std::optional<Time>           timeout)
{
    std::vector<IpAddress> addresses;

    if (hostname.isEmpty())
        return std::nullopt;

    // Check if the hostname is actually the string representation of an IP address
    if (const auto address = IpAddress::fromString(hostname.toAnsiString()); address)
    {
        addresses.emplace_back(*address);
        return addresses;
    }

    // Not a string representation of an IP address, do a full lookup

    auto encoded = encodeHostname(hostname);

    if (!servers.empty())
    {
        // Use user provided servers
        auto querySuccess = false;

        queryDns(
            [&](const char* data, std::size_t length, const char*, std::uint16_t responseType, std::uint16_t responseClass)
            {
                querySuccess = true;

                // AAAA, IN
                if ((responseType != 28) || (responseClass != 1))
                    return;

                if (length == 16)
                {
                    std::array<std::uint8_t, 16> bytes{};
                    std::memcpy(bytes.data(), data, 16);
                    if (std::any_of(bytes.begin(), bytes.end(), [](auto b) { return b != 0; }))
                        addresses.emplace_back(bytes);
                }
            },
            timeout,
            {{servers,
              28, // AAAA
              1,  // IN
              encoded}});

        queryDns(
            [&](const char* data, std::size_t length, const char*, std::uint16_t responseType, std::uint16_t responseClass)
            {
                querySuccess = true;

                // A, IN
                if ((responseType != 1) || (responseClass != 1))
                    return;

                if (const auto bytes = readU32(data, data + length); bytes != 0)