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/weak_result_type.h>
16#include <__type_traits/invoke.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
25template <class _Tp>
26class __mem_fn : public __weak_result_type<_Tp> {
27public:
28  // types
29  typedef _Tp type;
30
31private:
32  type __f_;
33
34public:
35  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __mem_fn(type __f) _NOEXCEPT : __f_(__f) {}
36
37  // invoke
38  template <class... _ArgTypes>
39  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __invoke_result_t<const _Tp&, _ArgTypes...>
40  operator()(_ArgTypes&&... __args) const _NOEXCEPT_(__is_nothrow_invocable_v<const _Tp&, _ArgTypes...>) {
41    return std::__invoke(__f_, std::forward<_ArgTypes>(__args)...);
42  }
43};
44
45template <class _Rp, class _Tp>
46inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __mem_fn<_Rp _Tp::*> mem_fn(_Rp _Tp::*__pm) _NOEXCEPT {
47  return __mem_fn<_Rp _Tp::*>(__pm);
48}
49
50_LIBCPP_END_NAMESPACE_STD
51
52#endif // _LIBCPP___FUNCTIONAL_MEM_FN_H