xref: /freebsd/contrib/llvm-project/libcxx/include/__functional/mem_fn.h (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___FUNCTIONAL_MEM_FN_H
11 #define _LIBCPP___FUNCTIONAL_MEM_FN_H
12 
13 #include <__config>
14 #include <__functional/binary_function.h>
15 #include <__functional/invoke.h>
16 #include <__functional/weak_result_type.h>
17 #include <__utility/forward.h>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _Tp>
26 class __mem_fn : public __weak_result_type<_Tp>
27 {
28 public:
29     // types
30     typedef _Tp type;
31 private:
32     type __f_;
33 
34 public:
35     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
36     __mem_fn(type __f) _NOEXCEPT : __f_(__f) {}
37 
38     // invoke
39     template <class... _ArgTypes>
40     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
41 
42     typename __invoke_return<type, _ArgTypes...>::type
43     operator() (_ArgTypes&&... __args) const {
44         return std::__invoke(__f_, std::forward<_ArgTypes>(__args)...);
45     }
46 };
47 
48 template<class _Rp, class _Tp>
49 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
50 __mem_fn<_Rp _Tp::*>
51 mem_fn(_Rp _Tp::* __pm) _NOEXCEPT
52 {
53     return __mem_fn<_Rp _Tp::*>(__pm);
54 }
55 
56 _LIBCPP_END_NAMESPACE_STD
57 
58 #endif // _LIBCPP___FUNCTIONAL_MEM_FN_H
59