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boost/property_tree/ptree_serialization.hpp

// ----------------------------------------------------------------------------
// Copyright (C) 2002-2006 Marcin Kalicinski
//
// Distributed under 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)
//
// For more information, see www.boost.org
// ----------------------------------------------------------------------------
#ifndef BOOST_PROPERTY_TREE_PTREE_SERIALIZATION_HPP_INCLUDED
#define BOOST_PROPERTY_TREE_PTREE_SERIALIZATION_HPP_INCLUDED

#include <boost/property_tree/ptree.hpp>

#include <boost/serialization/nvp.hpp>
#include <boost/serialization/collections_save_imp.hpp>
#include <boost/serialization/detail/stack_constructor.hpp>
#include <boost/serialization/split_free.hpp>
#include <boost/serialization/utility.hpp>
#include <boost/serialization/library_version_type.hpp>

namespace boost { namespace property_tree
{

    ///////////////////////////////////////////////////////////////////////////
    // boost::serialization support

    /**
     * Serialize the property tree to the given archive.
     * @note In addition to serializing to regular archives, this supports
     *       serializing to archives requiring name-value pairs, e.g. XML
     *       archives.  However, the output format in the XML archive is not
     *       guaranteed to be the same as that when using the Boost.PropertyTree
     *       library's @c boost::property_tree::xml_parser::write_xml.
     * @param ar The archive to which to save the serialized property tree.
     *           This archive should conform to the concept laid out by the
     *           Boost.Serialization library.
     * @param t The property tree to serialize.
     * @param file_version file_version for the archive.
     * @post @c ar will contain the serialized form of @c t.
     */
    template<class Archive, class K, class D, class C>
    inline void save(Archive &ar,
                     const basic_ptree<K, D, C> &t,
                     const unsigned int file_version)
    {
        using namespace boost::serialization;
        stl::save_collection<Archive, basic_ptree<K, D, C> >(ar, t);
        ar << make_nvp("data", t.data());
    }

    namespace detail
    {
        template <class Archive, class K, class D, class C>
        inline void load_children(Archive &ar,
                                  basic_ptree<K, D, C> &t)
        {
            namespace bsl = boost::serialization;

            typedef basic_ptree<K, D, C> tree;
            typedef typename tree::value_type value_type;
    
            bsl::collection_size_type count;
            ar >> BOOST_SERIALIZATION_NVP(count);
            bsl::item_version_type item_version(0);
            const bsl::library_version_type library_version(
                ar.get_library_version()
            );
            if(bsl::library_version_type(3) < library_version){
                ar >> BOOST_SERIALIZATION_NVP(item_version);
            }
            // Can't use the serialization helper, it expects resize() to exist
            // for default-constructible elements.
            // This is a copy/paste of the fallback version.
            t.clear();
            while(count-- > 0){
                bsl::detail::stack_construct<Archive, value_type>
                    u(ar, item_version);
                ar >> bsl::make_nvp("item", u.reference());
                t.push_back(u.reference());
                ar.reset_object_address(& t.back() , & u.reference());
            }
        }
    }

    /**
     * De-serialize the property tree to the given archive.
     * @note In addition to de-serializing from regular archives, this supports
     *       loading from archives requiring name-value pairs, e.g. XML
     *       archives. The format should be that used by
     *       boost::property_tree::save.
     * @param ar The archive from which to load the serialized property tree.
     *           This archive should conform to the concept laid out by the
     *           Boost.Serialization library.
     * @param t The property tree to de-serialize.
     * @param file_version file_version for the archive.
     * @post @c t will contain the de-serialized data from @c ar.
     */
    template<class Archive, class K, class D, class C>
    inline void load(Archive &ar,
                     basic_ptree<K, D, C> &t,
                     const unsigned int file_version)
    {
        namespace bsl = boost::serialization;

        detail::load_children(ar, t);
        ar >> bsl::make_nvp("data", t.data());
    }

    /**
     * Load or store the property tree using the given archive.
     * @param ar The archive from which to load or save the serialized property
     *           tree. The type of this archive will determine whether saving or
     *           loading is performed.
     * @param t The property tree to load or save.
     * @param file_version file_version for the archive.
     */
    template<class Archive, class K, class D, class C>
    inline void serialize(Archive &ar,
                          basic_ptree<K, D, C> &t,
                          const unsigned int file_version)
    {
        using namespace boost::serialization;
        split_free(ar, t, file_version);
    }

} }

#endif