detail/cpp03/deref_data_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2009 Christopher Schmidt
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007
0008 #ifndef BOOST_FUSION_CONTAINER_MAP_DETAIL_DEREF_DATA_IMPL_HPP
0009 #define BOOST_FUSION_CONTAINER_MAP_DETAIL_DEREF_DATA_IMPL_HPP
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/fusion/iterator/value_of.hpp>
0013 #include <boost/fusion/iterator/deref.hpp>
0014 #include <boost/fusion/support/detail/access.hpp>
0015 #include <boost/type_traits/is_const.hpp>
0016 #include <boost/mpl/if.hpp>
0017
0018 namespace boost { namespace fusion { namespace extension
0019 {
0020     template <typename>
0021     struct deref_data_impl;
0022
0023     template <>
0024     struct deref_data_impl<map_iterator_tag>
0025     {
0026         template <typename It>
0027         struct apply
0028         {
0029             typedef typename result_of::value_of<It>::type::second_type data;
0030
0031             typedef typename
0032                 mpl::if_<
0033                     is_const<typename It::seq_type>
0034                   , typename detail::cref_result<data>::type
0035                   , typename detail::ref_result<data>::type
0036                 >::type
0037             type;
0038
0039             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0040             static type
0041             call(It const& it)
0042             {
0043                 return fusion::deref(it).second;
0044             }
0045         };
0046     };
0047 }}}
0048
0049 #endif