xref: /freebsd/contrib/llvm-project/libcxx/include/__functional/not_fn.h (revision 43a5ec4eb41567cc92586503212743d89686d78f)
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/perfect_forward.h>
15 #include <__functional/invoke.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 {
28     template<class... _Args>
29     static _LIBCPP_CONSTEXPR_AFTER_CXX17 auto __call(_Args&&... __args)
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          class = _EnableIf<is_constructible_v<decay_t<_Fn>, _Fn> &&
37                            is_move_constructible_v<_Fn>>>
38 _LIBCPP_CONSTEXPR_AFTER_CXX17 auto not_fn(_Fn&& __f)
39 {
40     return __perfect_forward<__not_fn_op, _Fn>(_VSTD::forward<_Fn>(__f));
41 }
42 
43 #endif // _LIBCPP_STD_VER > 14
44 
45 _LIBCPP_END_NAMESPACE_STD
46 
47 #endif // _LIBCPP___FUNCTIONAL_NOT_FN_H
48