1bdd1243dSDimitry Andric // -*- C++ -*- 2bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 3bdd1243dSDimitry Andric // 4bdd1243dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5bdd1243dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6bdd1243dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7bdd1243dSDimitry Andric // 8bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 9bdd1243dSDimitry Andric 10bdd1243dSDimitry Andric #ifndef _LIBCPP___UTILITY_FORWARD_LIKE_H 11bdd1243dSDimitry Andric #define _LIBCPP___UTILITY_FORWARD_LIKE_H 12bdd1243dSDimitry Andric 13bdd1243dSDimitry Andric #include <__config> 14bdd1243dSDimitry Andric #include <__type_traits/conditional.h> 15bdd1243dSDimitry Andric #include <__type_traits/is_const.h> 16bdd1243dSDimitry Andric #include <__type_traits/is_reference.h> 17bdd1243dSDimitry Andric #include <__type_traits/remove_reference.h> 18bdd1243dSDimitry Andric 19bdd1243dSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20bdd1243dSDimitry Andric # pragma GCC system_header 21bdd1243dSDimitry Andric #endif 22bdd1243dSDimitry Andric 23bdd1243dSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 24bdd1243dSDimitry Andric 2506c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 23 26bdd1243dSDimitry Andric 27bdd1243dSDimitry Andric template <class _Ap, class _Bp> 28bdd1243dSDimitry Andric using _CopyConst = _If<is_const_v<_Ap>, const _Bp, _Bp>; 29bdd1243dSDimitry Andric 30bdd1243dSDimitry Andric template <class _Ap, class _Bp> 31bdd1243dSDimitry Andric using _OverrideRef = _If<is_rvalue_reference_v<_Ap>, remove_reference_t<_Bp>&&, _Bp&>; 32bdd1243dSDimitry Andric 33bdd1243dSDimitry Andric template <class _Ap, class _Bp> 34bdd1243dSDimitry Andric using _ForwardLike = _OverrideRef<_Ap&&, _CopyConst<remove_reference_t<_Ap>, remove_reference_t<_Bp>>>; 35bdd1243dSDimitry Andric 36bdd1243dSDimitry Andric template <class _Tp, class _Up> 37*0fca6ea1SDimitry Andric [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto 38*0fca6ea1SDimitry Andric forward_like(_LIBCPP_LIFETIMEBOUND _Up&& __ux) noexcept -> _ForwardLike<_Tp, _Up> { 39bdd1243dSDimitry Andric return static_cast<_ForwardLike<_Tp, _Up>>(__ux); 40bdd1243dSDimitry Andric } 41bdd1243dSDimitry Andric 4206c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 23 43bdd1243dSDimitry Andric 44bdd1243dSDimitry Andric _LIBCPP_END_NAMESPACE_STD 45bdd1243dSDimitry Andric 46bdd1243dSDimitry Andric #endif // _LIBCPP___UTILITY_FORWARD_LIKE_H 47