1 /*=============================================================================
2     Copyright (c) 2014 Kohei Takahashi
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 #if !defined(BOOST_FUSION_BUILD_STD_TUPLE_05292014_0100)
8 #define BOOST_FUSION_BUILD_STD_TUPLE_05292014_0100
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/fusion/support/detail/index_sequence.hpp>
12 #include <boost/fusion/iterator/equal_to.hpp>
13 #include <boost/fusion/iterator/next.hpp>
14 #include <boost/fusion/iterator/value_of.hpp>
15 #include <boost/fusion/iterator/deref.hpp>
16 #include <tuple>
17 #include <cstddef>
18 
19 namespace boost { namespace fusion { namespace detail
20 {
21     template <typename First, typename Last,
22               bool is_empty = result_of::equal_to<First, Last>::value>
23     struct build_std_tuple;
24 
25     template <typename First, typename Last>
26     struct build_std_tuple<First, Last, true>
27     {
28         typedef std::tuple<> type;
29 
30         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
31         static type
callboost::fusion::detail::build_std_tuple32         call(First const&, Last const&)
33         {
34             return type();
35         }
36     };
37 
38     template <typename T, typename Rest>
39     struct push_front_std_tuple;
40 
41     template <typename T, typename ...Rest>
42     struct push_front_std_tuple<T, std::tuple<Rest...> >
43     {
44         typedef std::tuple<T, Rest...> type;
45 
46         template <std::size_t ...I>
47         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
48         static type
indexed_callboost::fusion::detail::push_front_std_tuple49         indexed_call(T const& first, std::tuple<Rest...> const& rest, index_sequence<I...>)
50         {
51             return type(first, std::get<I>(rest)...);
52         }
53 
54         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
55         static type
callboost::fusion::detail::push_front_std_tuple56         call(T const& first, std::tuple<Rest...> const& rest)
57         {
58             typedef typename make_index_sequence<sizeof...(Rest)>::type gen;
59             return indexed_call(first, rest, gen());
60         }
61     };
62 
63     template <typename First, typename Last>
64     struct build_std_tuple<First, Last, false>
65     {
66         typedef
67             build_std_tuple<typename result_of::next<First>::type, Last>
68         next_build_std_tuple;
69 
70         typedef push_front_std_tuple<
71             typename result_of::value_of<First>::type
72           , typename next_build_std_tuple::type>
73         push_front;
74 
75         typedef typename push_front::type type;
76 
77         BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
78         static type
callboost::fusion::detail::build_std_tuple79         call(First const& f, Last const& l)
80         {
81             typename result_of::value_of<First>::type v = *f;
82             return push_front::call(
83                 v, next_build_std_tuple::call(fusion::next(f), l));
84         }
85     };
86 }}}
87 
88 #endif
89