Boost serialization: Problem reading strings from binary archive

Hello,

I hope this is the right place to post a question on Boost. If not,
please let me know where I can post this message and I will do so.

I am having a strange problem with std::string as I am trying to read
from a binary archive using Boost serialization. I am new to this, and
it is possible that I have not understood the usage. In the code
below, the string "faultblock" seems to be causing the problem. The
code crashes in the ia & tst line which is reading back the archive -
the stack indicates that it is trying to read an invalid string.

I have tried to minimize the code I need to post, but sorry if this is
still too much.

I'd appreciate any help with this. I am using Boost 1.34.0 on windows
XP.

Best Regards

Mahesh

//
// test.cpp
//
#include <iomanip>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <boost/archive/text_iarchive
..hpp>
#include <boost/archive/text_oarchive.hpp
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/serialization/base_object.hpp>
#include <boost/serialization/utility.hpp>
#include <boost/serialization/list.hpp>

#include "Attribute4dv.h"

using namespace std;

class Test
{
private:
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    {
    ar.template register_type<AttrDouble4dv>();
    ar.template register_type<AttrString4dv>();

    ar & _attrs;
    }

public:

    vector<Attribute4dv*> _attrs;

    Test() {}
    ~Test() {}

};

int main(int argc, char* arv[])
{
    // save data to archive
    {
    Test* tst = new Test;
    vector<double> dVals;
    dVals.push_back(1.1);
    dVals.push_back(2.2);
    AttrDouble4dv* attr1 = new AttrDouble4dv;
    attr1->_name = "attr1";
    attr1->_vals = dVals;
    tst->_attrs.push_back(attr1);

    vector<string> lut;
    lut.push_back("2001");
    lut.push_back("2002");
    vector<int> lutIndices;
    lutIndices.push_back (0);
    lutIndices.push_back(1);
    AttrString4dv* attr2 = new AttrString4dv;
    attr2->_name = "faultblock";
    attr2->_indices = lutIndices;
    attr2->_lut = lut;
    tst->_attrs.push_back(attr2);

    const Test* tst2 = tst;
    std::ofstream ofs("test.bin");
        boost::archive::binary_oarchive oa(ofs);
        oa & tst2;
    }

    // read data from archive
    {
    Test* tst;
    std::ifstream ifs("test.bin", std::ios::binary);
    boost::archive::binary_iarchive ia(ifs);
    ia & tst;
    int j = 0;
    }

    return 0;
}

//
// Attribute4dv.h
//
#ifndef _ATTRIBUTE4DV_H
#define _ATTRIBUTE4DV_H

#include <vector>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/base_object.hpp>
#include <boost/serialization/string.hpp>
#include <boost/serialization/vector.hpp>

// Base class
class Attribute4dv
{
 public:

    Attribute4dv() {}
    virtual ~Attribute4dv() {}

    // name of attribute
    std::string _name;

 private:

    // for serialization
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int version)
    {
    ar & _name;
    }

};

// double attributes
class AttrDouble4dv : public Attribute4dv
{
 public:

    AttrDouble4dv() {}
    ~AttrDouble4dv() {}

    std::vector<double> _vals;

 private:

    // for serialization
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int version)
    {
    // save/load base class info
    ar & boost::serialization::base_object<Attribute4dv>(*this);

    ar & _vals;
    }
};

// string attributes
class AttrString4dv : public Attribute4dv
{
 public:

    AttrString4dv() {}
    ~AttrString4dv() {}

    // a lookup table (LUT) of strings
    std::vector<std::string> _lut;
    // indices to the LUT
    std::vector<int> _indices;

 private:

    // for serialization
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int version)
    {
    // save/load base class info
    ar & boost::serialization::base_object<Attribute4dv>(*this);

    ar & _lut;
    ar & _indices;
    }
};

#endif // _ATTRIBUTE4DV_H