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1 | /*! |
2 | @file | |
3 | Defines `boost::hana::detail::variadic::split_at`. | |
4 | ||
5 | @copyright Louis Dionne 2013-2016 | |
6 | Distributed under the Boost Software License, Version 1.0. | |
7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_DETAIL_VARIADIC_SPLIT_AT_HPP | |
11 | #define BOOST_HANA_DETAIL_VARIADIC_SPLIT_AT_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | #include <boost/hana/functional/partial.hpp> | |
15 | #include <boost/hana/functional/reverse_partial.hpp> | |
16 | ||
17 | #include <cstddef> | |
18 | ||
19 | ||
20 | BOOST_HANA_NAMESPACE_BEGIN namespace detail { namespace variadic { | |
21 | template <std::size_t n> | |
22 | struct split_at_t { | |
23 | template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename X7, typename X8, typename ...Xs> | |
24 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, X7&& x7, X8&& x8, Xs&& ...xs) const { | |
25 | return split_at_t<n - 8>{}( | |
26 | hana::partial(static_cast<F&&>(f), | |
27 | static_cast<X1&&>(x1), | |
28 | static_cast<X2&&>(x2), | |
29 | static_cast<X3&&>(x3), | |
30 | static_cast<X4&&>(x4), | |
31 | static_cast<X5&&>(x5), | |
32 | static_cast<X6&&>(x6), | |
33 | static_cast<X7&&>(x7), | |
34 | static_cast<X8&&>(x8) | |
35 | ), | |
36 | static_cast<Xs&&>(xs)... | |
37 | ); | |
38 | } | |
39 | }; | |
40 | ||
41 | template <> | |
42 | struct split_at_t<0> { | |
43 | template <typename F, typename ...Xs> | |
44 | constexpr decltype(auto) operator()(F&& f, Xs&& ...xs) const { | |
45 | return static_cast<F&&>(f)()(static_cast<Xs&&>(xs)...); | |
46 | } | |
47 | }; | |
48 | ||
49 | template <> | |
50 | struct split_at_t<1> { | |
51 | template <typename F, typename X1, typename ...Xs> | |
52 | constexpr decltype(auto) operator()(F&& f, X1&& x1, Xs&& ...xs) const { | |
53 | return static_cast<F&&>(f)( | |
54 | static_cast<X1&&>(x1) | |
55 | )(static_cast<Xs&&>(xs)...); | |
56 | } | |
57 | }; | |
58 | ||
59 | template <> | |
60 | struct split_at_t<2> { | |
61 | template <typename F, typename X1, typename X2, typename ...Xs> | |
62 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, Xs&& ...xs) const { | |
63 | return static_cast<F&&>(f)( | |
64 | static_cast<X1&&>(x1), | |
65 | static_cast<X2&&>(x2) | |
66 | )(static_cast<Xs&&>(xs)...); | |
67 | } | |
68 | }; | |
69 | ||
70 | template <> | |
71 | struct split_at_t<3> { | |
72 | template <typename F, typename X1, typename X2, typename X3, typename ...Xs> | |
73 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, Xs&& ...xs) const { | |
74 | return static_cast<F&&>(f)( | |
75 | static_cast<X1&&>(x1), | |
76 | static_cast<X2&&>(x2), | |
77 | static_cast<X3&&>(x3) | |
78 | )(static_cast<Xs&&>(xs)...); | |
79 | } | |
80 | }; | |
81 | ||
82 | template <> | |
83 | struct split_at_t<4> { | |
84 | template <typename F, typename X1, typename X2, typename X3, typename X4, typename ...Xs> | |
85 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, Xs&& ...xs) const { | |
86 | return static_cast<F&&>(f)( | |
87 | static_cast<X1&&>(x1), | |
88 | static_cast<X2&&>(x2), | |
89 | static_cast<X3&&>(x3), | |
90 | static_cast<X4&&>(x4) | |
91 | )(static_cast<Xs&&>(xs)...); | |
92 | } | |
93 | }; | |
94 | ||
95 | template <> | |
96 | struct split_at_t<5> { | |
97 | template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename ...Xs> | |
98 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, Xs&& ...xs) const { | |
99 | return static_cast<F&&>(f)( | |
100 | static_cast<X1&&>(x1), | |
101 | static_cast<X2&&>(x2), | |
102 | static_cast<X3&&>(x3), | |
103 | static_cast<X4&&>(x4), | |
104 | static_cast<X5&&>(x5) | |
105 | )(static_cast<Xs&&>(xs)...); | |
106 | } | |
107 | }; | |
108 | ||
109 | template <> | |
110 | struct split_at_t<6> { | |
111 | template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename ...Xs> | |
112 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, Xs&& ...xs) const { | |
113 | return static_cast<F&&>(f)( | |
114 | static_cast<X1&&>(x1), | |
115 | static_cast<X2&&>(x2), | |
116 | static_cast<X3&&>(x3), | |
117 | static_cast<X4&&>(x4), | |
118 | static_cast<X5&&>(x5), | |
119 | static_cast<X6&&>(x6) | |
120 | )(static_cast<Xs&&>(xs)...); | |
121 | } | |
122 | }; | |
123 | ||
124 | template <> | |
125 | struct split_at_t<7> { | |
126 | template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename X7, typename ...Xs> | |
127 | constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, X7&& x7, Xs&& ...xs) const { | |
128 | return static_cast<F&&>(f)( | |
129 | static_cast<X1&&>(x1), | |
130 | static_cast<X2&&>(x2), | |
131 | static_cast<X3&&>(x3), | |
132 | static_cast<X4&&>(x4), | |
133 | static_cast<X5&&>(x5), | |
134 | static_cast<X6&&>(x6), | |
135 | static_cast<X7&&>(x7) | |
136 | )(static_cast<Xs&&>(xs)...); | |
137 | } | |
138 | }; | |
139 | ||
140 | template <std::size_t n> | |
141 | struct _makesplit_at_t { | |
142 | template <typename ...Xs> | |
143 | constexpr decltype(auto) operator()(Xs&& ...xs) const { | |
144 | return hana::reverse_partial(split_at_t<n>{}, | |
145 | static_cast<Xs&&>(xs)...); | |
146 | } | |
147 | }; | |
148 | ||
149 | template <std::size_t n> | |
150 | constexpr _makesplit_at_t<n> split_at{}; | |
151 | }} BOOST_HANA_NAMESPACE_END | |
152 | ||
153 | #endif // !BOOST_HANA_DETAIL_VARIADIC_SPLIT_AT_HPP |