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1 | #ifndef BOOST_LEAF_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED |
2 | #define BOOST_LEAF_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED | |
3 | ||
4 | // Copyright (c) 2018-2020 Emil Dotchevski and Reverge Studios, Inc. | |
5 | ||
6 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
7 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
8 | ||
9 | #ifndef BOOST_LEAF_ENABLE_WARNINGS | |
10 | # if defined(__clang__) | |
11 | # pragma clang system_header | |
12 | # elif (__GNUC__*100+__GNUC_MINOR__>301) | |
13 | # pragma GCC system_header | |
14 | # elif defined(_MSC_VER) | |
15 | # pragma warning(push,1) | |
16 | # endif | |
17 | #endif | |
18 | ||
19 | #include <boost/leaf/detail/mp11.hpp> | |
20 | #include <tuple> | |
21 | ||
22 | namespace boost { namespace leaf { | |
23 | ||
24 | namespace leaf_detail | |
25 | { | |
26 | template<class...> | |
27 | struct gcc49_workaround //Thanks Glen Fernandes | |
28 | { | |
29 | using type = void; | |
30 | }; | |
31 | ||
32 | template<class... T> | |
33 | using void_t = typename gcc49_workaround<T...>::type; | |
34 | ||
35 | template<class F,class V=void> | |
36 | struct function_traits | |
37 | { | |
38 | constexpr static int arity = -1; | |
39 | }; | |
40 | ||
41 | template<class F> | |
42 | struct function_traits<F, void_t<decltype(&F::operator())>> | |
43 | { | |
44 | private: | |
45 | ||
46 | using tr = function_traits<decltype(&F::operator())>; | |
47 | ||
48 | public: | |
49 | ||
50 | using return_type = typename tr::return_type; | |
51 | static constexpr int arity = tr::arity - 1; | |
52 | ||
53 | using mp_args = typename leaf_detail_mp11::mp_rest<typename tr::mp_args>; | |
54 | ||
55 | template <int I> | |
56 | struct arg: | |
57 | tr::template arg<I+1> | |
58 | { | |
59 | }; | |
60 | }; | |
61 | ||
62 | template<class R, class... A> | |
63 | struct function_traits<R(A...)> | |
64 | { | |
65 | using return_type = R; | |
66 | static constexpr int arity = sizeof...(A); | |
67 | ||
68 | using mp_args = leaf_detail_mp11::mp_list<A...>; | |
69 | ||
70 | template <int I> | |
71 | struct arg | |
72 | { | |
73 | static_assert(I < arity, "I out of range"); | |
74 | using type = typename std::tuple_element<I,std::tuple<A...>>::type; | |
75 | }; | |
76 | }; | |
77 | ||
78 | template<class F> struct function_traits<F&> : function_traits<F> { }; | |
79 | template<class F> struct function_traits<F&&> : function_traits<F> { }; | |
80 | template<class R, class... A> struct function_traits<R(*)(A...)> : function_traits<R(A...)> { }; | |
81 | template<class R, class... A> struct function_traits<R(* &)(A...)> : function_traits<R(A...)> { }; | |
82 | template<class R, class... A> struct function_traits<R(* const &)(A...)> : function_traits<R(A...)> { }; | |
83 | template<class C, class R, class... A> struct function_traits<R(C::*)(A...)> : function_traits<R(C&,A...)> { }; | |
84 | template<class C, class R, class... A> struct function_traits<R(C::*)(A...) const> : function_traits<R(C const &,A...)> { }; | |
85 | template<class C, class R> struct function_traits<R(C::*)> : function_traits<R(C&)> { }; | |
86 | ||
87 | template <class F> | |
88 | using fn_return_type = typename function_traits<F>::return_type; | |
89 | ||
90 | template <class F, int I> | |
91 | using fn_arg_type = typename function_traits<F>::template arg<I>::type; | |
92 | ||
93 | template <class F> | |
94 | using fn_mp_args = typename function_traits<F>::mp_args; | |
95 | ||
96 | } | |
97 | ||
98 | } } | |
99 | ||
100 | #endif |