not_fn.h 1.8 KB

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