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 <utility>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #pragma GCC system_header
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 #if _LIBCPP_STD_VER > 14
25 
26 struct __not_fn_op {
27     template <class... _Args>
28     _LIBCPP_HIDE_FROM_ABI
29     _LIBCPP_CONSTEXPR_AFTER_CXX17 auto operator()(_Args&&... __args) const
30         noexcept(noexcept(!_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
31         -> decltype(      !_VSTD::invoke(_VSTD::forward<_Args>(__args)...))
32         { return          !_VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
33 };
34 
35 template <class _Fn>
36 struct __not_fn_t : __perfect_forward<__not_fn_op, _Fn> {
37     using __perfect_forward<__not_fn_op, _Fn>::__perfect_forward;
38 };
39 
40 template <class _Fn, class = enable_if_t<
41     is_constructible_v<decay_t<_Fn>, _Fn> &&
42     is_move_constructible_v<decay_t<_Fn>>
43 >>
44 _LIBCPP_HIDE_FROM_ABI
45 _LIBCPP_CONSTEXPR_AFTER_CXX17 auto not_fn(_Fn&& __f) {
46     return __not_fn_t<decay_t<_Fn>>(_VSTD::forward<_Fn>(__f));
47 }
48 
49 #endif // _LIBCPP_STD_VER > 14
50 
51 _LIBCPP_END_NAMESPACE_STD
52 
53 #endif // _LIBCPP___FUNCTIONAL_NOT_FN_H
54