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_NOT_FN_H
11#define _LIBCPP___FUNCTIONAL_NOT_FN_H
12
13#include <__config>
14#include <__functional/invoke.h>
15#include <__functional/perfect_forward.h>
16#include <__type_traits/decay.h>
17#include <__type_traits/enable_if.h>
18#include <__type_traits/is_constructible.h>
19#include <__utility/forward.h>
20
21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22# pragma GCC system_header
23#endif
24
25_LIBCPP_BEGIN_NAMESPACE_STD
26
27#if _LIBCPP_STD_VER >= 17
28
29struct __not_fn_op {
30 template <class... _Args>
31 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto operator()(_Args&&... __args) const
32 noexcept(noexcept(!std::invoke(std::forward<_Args>(__args)...)))
33 -> decltype(!std::invoke(std::forward<_Args>(__args)...)) {
34 return !std::invoke(std::forward<_Args>(__args)...);
35 }
36};
37
38template <class _Fn>
39struct __not_fn_t : __perfect_forward<__not_fn_op, _Fn> {
40 using __perfect_forward<__not_fn_op, _Fn>::__perfect_forward;
41};
42
43template <class _Fn,
44 class = enable_if_t< is_constructible_v<decay_t<_Fn>, _Fn> && is_move_constructible_v<decay_t<_Fn>> >>
45_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto not_fn(_Fn&& __f) {
46 return __not_fn_t<decay_t<_Fn>>(std::forward<_Fn>(__f));
47}
48
49#endif // _LIBCPP_STD_VER >= 17
50
51_LIBCPP_END_NAMESPACE_STD
52
53#endif // _LIBCPP___FUNCTIONAL_NOT_FN_H
54