1 /*=============================================================================
2     Copyright (c) 2009 Hartmut Kaiser
3 
4     Distributed under the Boost Software License, Version 1.0. (See accompanying
5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 ==============================================================================*/
7 
8 #if !defined(BOOST_FUSION_NVIEW_SEP_23_2009_0948PM)
9 #define BOOST_FUSION_NVIEW_SEP_23_2009_0948PM
10 
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/mpl/size.hpp>
13 #include <boost/mpl/if.hpp>
14 #include <boost/mpl/vector_c.hpp>
15 #include <boost/utility/result_of.hpp>
16 
17 #include <boost/type_traits/remove_reference.hpp>
18 #include <boost/type_traits/add_reference.hpp>
19 #include <boost/type_traits/add_const.hpp>
20 
21 #include <boost/fusion/support/is_view.hpp>
22 #include <boost/fusion/support/category_of.hpp>
23 #include <boost/fusion/support/sequence_base.hpp>
24 #include <boost/fusion/container/vector.hpp>
25 #include <boost/fusion/view/transform_view.hpp>
26 
27 #include <boost/config.hpp>
28 
29 namespace boost { namespace fusion
30 {
31     namespace detail
32     {
33         struct addref
34         {
35             template<typename Sig>
36             struct result;
37 
38             template<typename U>
39             struct result<addref(U)> : add_reference<U> {};
40 
41 #ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
42             template <typename T>
43             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
44             typename add_reference<T>::type
operator ()boost::fusion::detail::addref45             operator()(T& x) const
46             {
47                 return x;
48             }
49 #else
50             template <typename T>
51             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
52             typename result<addref(T)>::type
operator ()boost::fusion::detail::addref53             operator()(T&& x) const
54             {
55                 return x;
56             }
57 #endif
58         };
59 
60         struct addconstref
61         {
62             template<typename Sig>
63             struct result;
64 
65             template<typename U>
66             struct result<addconstref(U)>
67               : add_reference<typename add_const<U>::type>
68             {};
69 
70             template <typename T>
71             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
72             typename add_reference<typename add_const<T>::type>::type
operator ()boost::fusion::detail::addconstref73             operator()(T& x) const
74             {
75                 return x;
76             }
77 
78             template <typename T>
79             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
80             typename add_reference<typename add_const<T>::type>::type
operator ()boost::fusion::detail::addconstref81             operator()(T const& x) const
82             {
83                 return x;
84             }
85         };
86     }
87 
88     struct nview_tag;
89     struct random_access_traversal_tag;
90     struct fusion_sequence_tag;
91 
92     template<typename Sequence, typename Indicies>
93     struct nview
94       : sequence_base<nview<Sequence, Indicies> >
95     {
96         typedef nview_tag fusion_tag;
97         typedef fusion_sequence_tag tag; // this gets picked up by MPL
98         typedef random_access_traversal_tag category;
99 
100         typedef mpl::true_ is_view;
101         typedef Indicies index_type;
102         typedef typename mpl::size<Indicies>::type size;
103 
104         typedef typename mpl::if_<
105             is_const<Sequence>, detail::addconstref, detail::addref
106         >::type transform_type;
107         typedef transform_view<Sequence, transform_type> transform_view_type;
108         typedef typename result_of::as_vector<transform_view_type>::type
109             sequence_type;
110 
111         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
nviewboost::fusion::nview112         explicit nview(Sequence& val)
113           : seq(sequence_type(transform_view_type(val, transform_type())))
114         {}
115 
116         sequence_type seq;
117     };
118 
119 }}
120 
121 // define the nview() generator functions
122 #include <boost/fusion/view/nview/detail/nview_impl.hpp>
123 
124 #endif
125 
126 
127