Re: How to serialize reference members using boost::serialization

From:

Abhishek Padmanabh <abhishek.padmanabh@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Sat, 21 Apr 2007 02:46:14 CST

Message-ID:

<1177135526.514661.85210@e65g2000hsc.googlegroups.com>

I just noticed that I was advised about posting the code directly
here. So, here is my another attempt to find an answer - posting the
best I could do about serializing reference members:

[CODE]

#include <iostream>
#include <fstream>
#include <string>

#include <boost/archive/xml_iarchive.hpp>
#include <boost/archive/xml_oarchive.hpp>

//for name value pairs when doing XML archiving
#include <boost/serialization/nvp.hpp>

class MyClassWithNoDefaultConstructor;
std::ostream& operator<<(std::ostream& os, const
MyClassWithNoDefaultConstructor& object);

class MyClassWithNoDefaultConstructor
{
    public:
        MyClassWithNoDefaultConstructor(int i, char& c_)
            : intMember(i), c(c_)
        {}
        const int& getConstIntMember() const
        {
            return intMember;
        }
        const char& getConstCharRefMember() const
        {
            return c;
        }
    private:
        const int intMember;
        /*const*/ char& c;
        template<class Archive>
        void serialize(Archive& ar, const unsigned int version)
        {
            //ar & BOOST_SERIALIZATION_NVP(c);
        }

    friend class boost::serialization::access;
    friend std::ostream& operator<<(std::ostream& os, const
MyClassWithNoDefaultConstructor& object);
};

std::ostream& operator<<(std::ostream& os, const
MyClassWithNoDefaultConstructor& object)
{
    os << "\nMyClassWithNoDefaultConstructor contents:\n";
    os << "intMember - " << object.intMember << "\n";
    os << "charmember - " << object.c << "\n";
    return os;
}

namespace boost
{
    namespace serialization
    {
        template<class Archive>
        inline void save_construct_data(Archive & ar, const
MyClassWithNoDefaultConstructor* t, const unsigned int file_version)
        {
            ar << boost::serialization::make_nvp("intMember", t-

getConstIntMember());

ar << boost::serialization::make_nvp("charrefMember", t-

getConstCharRefMember());

}

        template<class Archive>
        inline void load_construct_data(Archive & ar,
MyClassWithNoDefaultConstructor* t, const unsigned int file_version)
        {
            int m;
            char *c = new char();
            ar >> boost::serialization::make_nvp("intMember",m);
            ar >> boost::serialization::make_nvp("charrefMember",*c);
            ::new(t)MyClassWithNoDefaultConstructor(m,*c);
        }
    }
}

void SerializeMyClassWithNoDefaultConstructor(const std::string&
filename)
{
    char c = 'X';
     MyClassWithNoDefaultConstructor object(111, c);
     std::ofstream ofs(filename.c_str());
     assert(ofs.good());
     boost::archive::xml_oarchive xml_oa(ofs);
     MyClassWithNoDefaultConstructor * object_ptr = & object;
     xml_oa << BOOST_SERIALIZATION_NVP(object_ptr);
}

void DeserializeMyClassWithNoDefaultConstructor(const std::string&
filename)
{
    MyClassWithNoDefaultConstructor * object_ptr;
    std::ifstream ifs(filename.c_str());
    assert(ifs.good());
    boost::archive::xml_iarchive xml_ia(ifs);
    xml_ia >> BOOST_SERIALIZATION_NVP(object_ptr);
    std::cout << *object_ptr;
    delete &(object_ptr->getConstCharRefMember()); //delete the char
created on free store inside load_construct_data...
    delete object_ptr;
}

int main()
{
    const std::string filenameMyClassWithNoDefaultConstructor="/tmp/
testfileMyClassWithNoDefaultConstructor.xml";
    try
    {

SerializeMyClassWithNoDefaultConstructor(filenameMyClassWithNoDefaultConstructor);

DeserializeMyClassWithNoDefaultConstructor(filenameMyClassWithNoDefaultConstructor);
    }
    catch(const boost::archive::archive_exception& ex)
    {
        std::cout << ex.what() << "\n";
    }
    catch(const std::exception& ex)
    {
        std::cout << ex.what() << "\n";
    }
    return 0;
}

Any suggestions about what am I doing wrong? Or if this is the right
way to do this. And any problems associated with it - or any
alternative solutions or if what I am doing doesn't make sense? Thanks
very much in advance!

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