| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___UTILITY_FORWARD_LIKE_H |
| #define _LIBCPP___UTILITY_FORWARD_LIKE_H |
| |
| #include <__config> |
| #include <__type_traits/conditional.h> |
| #include <__type_traits/is_const.h> |
| #include <__type_traits/is_reference.h> |
| #include <__type_traits/remove_reference.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 20 |
| |
| template <class _Ap, class _Bp> |
| using _CopyConst = _If<is_const_v<_Ap>, const _Bp, _Bp>; |
| |
| template <class _Ap, class _Bp> |
| using _OverrideRef = _If<is_rvalue_reference_v<_Ap>, remove_reference_t<_Bp>&&, _Bp&>; |
| |
| template <class _Ap, class _Bp> |
| using _ForwardLike = _OverrideRef<_Ap&&, _CopyConst<remove_reference_t<_Ap>, remove_reference_t<_Bp>>>; |
| |
| template <class _Tp, class _Up> |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto forward_like(_Up&& __ux) noexcept -> _ForwardLike<_Tp, _Up> { |
| return static_cast<_ForwardLike<_Tp, _Up>>(__ux); |
| } |
| |
| #endif // _LIBCPP_STD_VER > 20 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___UTILITY_FORWARD_LIKE_H |
