view/nview/nview.hpp

0001 /*=============================================================================
0002     Copyright (c) 2009 Hartmut Kaiser
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 #if !defined(BOOST_FUSION_NVIEW_SEP_23_2009_0948PM)
0009 #define BOOST_FUSION_NVIEW_SEP_23_2009_0948PM
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/mpl/if.hpp>
0013
0014 #include <boost/type_traits/add_reference.hpp>
0015 #include <boost/type_traits/add_const.hpp>
0016
0017 #include <boost/fusion/support/is_view.hpp>
0018 #include <boost/fusion/support/sequence_base.hpp>
0019 #include <boost/fusion/container/vector.hpp>
0020 #include <boost/fusion/sequence/intrinsic/size.hpp>
0021 #include <boost/fusion/view/transform_view.hpp>
0022
0023 #include <boost/config.hpp>
0024
0025 namespace boost { namespace fusion
0026 {
0027     namespace detail
0028     {
0029         struct addref
0030         {
0031             template<typename Sig>
0032             struct result;
0033
0034             template<typename U>
0035             struct result<addref(U)> : add_reference<U> {};
0036
0037 #ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
0038             template <typename T>
0039             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0040             typename add_reference<T>::type
0041             operator()(T& x) const
0042             {
0043                 return x;
0044             }
0045 #else
0046             template <typename T>
0047             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0048             typename result<addref(T)>::type
0049             operator()(T&& x) const
0050             {
0051                 return x;
0052             }
0053 #endif
0054         };
0055
0056         struct addconstref
0057         {
0058             template<typename Sig>
0059             struct result;
0060
0061             template<typename U>
0062             struct result<addconstref(U)>
0063               : add_reference<typename add_const<U>::type>
0064             {};
0065
0066             template <typename T>
0067             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0068             typename add_reference<typename add_const<T>::type>::type
0069             operator()(T& x) const
0070             {
0071                 return x;
0072             }
0073
0074             template <typename T>
0075             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0076             typename add_reference<typename add_const<T>::type>::type
0077             operator()(T const& x) const
0078             {
0079                 return x;
0080             }
0081         };
0082     }
0083
0084     struct nview_tag;
0085     struct random_access_traversal_tag;
0086     struct fusion_sequence_tag;
0087
0088     template<typename Sequence, typename Indicies>
0089     struct nview
0090       : sequence_base<nview<Sequence, Indicies> >
0091     {
0092         typedef nview_tag fusion_tag;
0093         typedef fusion_sequence_tag tag; // this gets picked up by MPL
0094         typedef random_access_traversal_tag category;
0095
0096         typedef mpl::true_ is_view;
0097         typedef Indicies index_type;
0098         typedef typename result_of::size<Indicies>::type size;
0099
0100         typedef typename mpl::if_<
0101             is_const<Sequence>, detail::addconstref, detail::addref
0102         >::type transform_type;
0103         typedef transform_view<Sequence, transform_type> transform_view_type;
0104         typedef typename result_of::as_vector<transform_view_type>::type
0105             sequence_type;
0106
0107         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0108         explicit nview(Sequence& val)
0109           : seq(sequence_type(transform_view_type(val, transform_type())))
0110         {}
0111
0112         sequence_type seq;
0113     };
0114
0115 }}
0116
0117 // define the nview() generator functions
0118 #include <boost/fusion/view/nview/detail/nview_impl.hpp>
0119
0120 #endif
0121
0122