nvp.hpp

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#ifndef BOOST_SERIALIZATION_NVP_HPP
#define BOOST_SERIALIZATION_NVP_HPP
 
// MS compatible compilers support #pragma once
#if defined(_MSC_VER)
# pragma once
#endif
 
// nvp.hpp: interface for serialization system.
 
// (C) Copyright 2002 Robert Ramey - http://www.rrsd.com . 
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
 
//  See http://www.boost.org for updates, documentation, and revision history.
 
#include <utility>
 
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
 
#include <boost/serialization/level.hpp>
#include <boost/serialization/tracking.hpp>
#include <boost/serialization/split_member.hpp>
#include <boost/serialization/base_object.hpp>
#include <boost/serialization/traits.hpp>
#include <boost/serialization/wrapper.hpp>
 
namespace boost {
namespace serialization {
 
template<class T>
struct nvp : 
    public std::pair<const char *, T *>,
    public wrapper_traits<const nvp< T > >
{
//private:
    nvp(const nvp & rhs) :
        std::pair<const char *, T *>(rhs.first, rhs.second)
    {}
public:
    explicit nvp(const char * name_, T & t) :
        // note: added _ to suppress useless gcc warning
        std::pair<const char *, T *>(name_, & t)
    {}
 
    const char * name() const {
        return this->first;
    }
    T & value() const {
        return *(this->second);
    }
 
    const T & const_value() const {
        return *(this->second);
    }
 
    template<class Archive>
    void save(
        Archive & ar,
        const unsigned int /* file_version */
    ) const {
        ar.operator<<(const_value());
    }
    template<class Archive>
    void load(
        Archive & ar,
        const unsigned int /* file_version */
    ){
        ar.operator>>(value());
    }
    BOOST_SERIALIZATION_SPLIT_MEMBER()
};
 
template<class T>
inline
const nvp< T > make_nvp(const char * name, T & t){
    return nvp< T >(name, t);
}
 
// to maintain efficiency and portability, we want to assign
// specific serialization traits to all instances of this wrappers.
// we can't strait forward method below as it depends upon
// Partial Template Specialization and doing so would mean that wrappers
// wouldn't be treated the same on different platforms.  This would
// break archive portability. Leave this here as reminder not to use it !!!
 
template <class T>
struct implementation_level<nvp< T > >
{
    typedef mpl::integral_c_tag tag;
    typedef mpl::int_<object_serializable> type;
    BOOST_STATIC_CONSTANT(int, value = implementation_level::type::value);
};
 
// nvp objects are generally created on the stack and are never tracked
template<class T>
struct tracking_level<nvp< T > >
{
    typedef mpl::integral_c_tag tag;
    typedef mpl::int_<track_never> type;
    BOOST_STATIC_CONSTANT(int, value = tracking_level::type::value);
};
 
} // seralization
} // boost
 
#include <boost/preprocessor/stringize.hpp>
 
#define BOOST_SERIALIZATION_NVP(name)                              \
    boost::serialization::make_nvp(BOOST_PP_STRINGIZE(name), name)
 
 
#define BOOST_SERIALIZATION_BASE_OBJECT_NVP(name)                  \
    boost::serialization::make_nvp(                                \
        BOOST_PP_STRINGIZE(name),                                  \
        boost::serialization::base_object<name >(*this)            \
    )
 
 
#endif // BOOST_SERIALIZATION_NVP_HPP