Question

I’m doing serialization with boost:

bool saveParams(std::string filename)
{
    using boost::serialization::make_nvp;
    std::ofstream ofs(filename.c_str());
    if(ofs.is_open() == false) return false;
    boost::archive::xml_oarchive xml(ofs);

    xml << make_nvp("Param1", param1value);
    xml << make_nvp("Param2", param2value);
    xml << make_nvp("Param3", param3value);
    xml << make_nvp("Param4", param4value);
}

Loading is done with:

bool loadParams(std::string filename)
{
    using boost::serialization::make_nvp;
    std::ifstream ifs(filename.c_str());
    if(ifs.is_open() == false) return false;
    boost::archive::xml_iarchive xml(ifs);

    xml >> BOOST_SERIALIZATION_NVP(param1value);
    xml >> BOOST_SERIALIZATION_NVP(param2value);
    xml >> BOOST_SERIALIZATION_NVP(param3value);
    xml >> BOOST_SERIALIZATION_NVP(param4value);
}

Now I want to add Param5. How to add aditional version info and cope it when loading? I’ve found in docs how to do it when class is serialized with BOOST_CLASS_VERSION(serialized_class, version).

Answer 1

So I will present my ugly solution as an answer. When better solution will appear I will accept it.

I’ve coped versions with exceptions:

bool loadParams(std::string filename)
{
    using boost::serialization::make_nvp;
    std::ifstream ifs(filename.c_str());
    if(ifs.is_open() == false) return false;
    boost::archive::xml_iarchive xml(ifs);

    try
    {
       xml >> BOOST_SERIALIZATION_NVP(param1value);
       xml >> BOOST_SERIALIZATION_NVP(param2value);
       xml >> BOOST_SERIALIZATION_NVP(param3value);
       xml >> BOOST_SERIALIZATION_NVP(param4value);
    }
    catch(boost::archive::archive_exception e)
    {
       qDebug()<<"Exception: "<<e.what();
    }
    try
    {
       xml >> BOOST_SERIALIZATION_NVP(newParam);
    }
    catch(boost::archive::archive_exception e)
    {
       qDebug()<<"New version!";
    }
}