Method GetMessageType

src/net.cpp:1420–1458

}

std::optional<std::string> V2Transport::GetMessageType(std::span<const uint8_t>& contents) noexcept
{
    if (contents.size() == 0) return std::nullopt; // Empty contents
    uint8_t first_byte = contents[0];
    contents = contents.subspan(1); // Strip first byte.

    if (first_byte != 0) {
        // Short (1 byte) encoding.
        if (first_byte < std::size(V2_MESSAGE_IDS)) {
            // Valid short message id.
            return V2_MESSAGE_IDS[first_byte];
        } else {
            // Unknown short message id.
            return std::nullopt;
        }
    }

    if (contents.size() < CMessageHeader::MESSAGE_TYPE_SIZE) {
        return std::nullopt; // Long encoding needs 12 message type bytes.
    }

    size_t msg_type_len{0};
    while (msg_type_len < CMessageHeader::MESSAGE_TYPE_SIZE && contents[msg_type_len] != 0) {
        // Verify that message type bytes before the first 0x00 are in range.
        if (contents[msg_type_len] < ' ' || contents[msg_type_len] > 0x7F) {
            return {};
        }
        ++msg_type_len;
    }
    std::string ret{reinterpret_cast<const char*>(contents.data()), msg_type_len};
    while (msg_type_len < CMessageHeader::MESSAGE_TYPE_SIZE) {
        // Verify that message type bytes after the first 0x00 are also 0x00.
        if (contents[msg_type_len] != 0) return {};
        ++msg_type_len;
    }
    // Strip message type bytes of contents.
    contents = contents.subspan(CMessageHeader::MESSAGE_TYPE_SIZE);
    return ret;
}

CNetMessage V2Transport::GetReceivedMessage(NodeClock::time_point time, bool& reject_message) noexcept
{