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___ITERATOR_ITER_MOVE_H 11 #define _LIBCPP___ITERATOR_ITER_MOVE_H 12 13 #include <__concepts/class_or_enum.h> 14 #include <__config> 15 #include <__iterator/iterator_traits.h> 16 #include <__type_traits/is_reference.h> 17 #include <__type_traits/remove_cvref.h> 18 #include <__utility/declval.h> 19 #include <__utility/forward.h> 20 #include <__utility/move.h> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 _LIBCPP_PUSH_MACROS 27 #include <__undef_macros> 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 #if _LIBCPP_STD_VER >= 20 32 33 // [iterator.cust.move] 34 35 namespace ranges { 36 namespace __iter_move { 37 38 void iter_move(); 39 40 template <class _Tp> 41 concept __unqualified_iter_move = __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 42 // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap 43 iter_move(std::forward<_Tp>(__t)); 44 }; 45 46 template <class _Tp> 47 concept __move_deref = !__unqualified_iter_move<_Tp> && requires(_Tp&& __t) { 48 *__t; 49 requires is_lvalue_reference_v<decltype(*__t)>; 50 }; 51 52 template <class _Tp> 53 concept __just_deref = !__unqualified_iter_move<_Tp> && !__move_deref<_Tp> && requires(_Tp&& __t) { 54 *__t; 55 requires(!is_lvalue_reference_v<decltype(*__t)>); 56 }; 57 58 // [iterator.cust.move] 59 60 struct __fn { 61 // NOLINTBEGIN(libcpp-robust-against-adl) iter_move ADL calls should only be made through ranges::iter_move 62 template <class _Ip> 63 requires __unqualified_iter_move<_Ip> 64 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const 65 noexcept(noexcept(iter_move(std::forward<_Ip>(__i)))) { 66 return iter_move(std::forward<_Ip>(__i)); 67 } 68 // NOLINTEND(libcpp-robust-against-adl) 69 70 template <class _Ip> 71 requires __move_deref<_Ip> 72 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 73 noexcept(noexcept(std::move(*std::forward<_Ip>(__i)))) -> decltype(std::move(*std::forward<_Ip>(__i))) { 74 return std::move(*std::forward<_Ip>(__i)); 75 } 76 77 template <class _Ip> 78 requires __just_deref<_Ip> 79 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 80 noexcept(noexcept(*std::forward<_Ip>(__i))) -> decltype(*std::forward<_Ip>(__i)) { 81 return *std::forward<_Ip>(__i); 82 } 83 }; 84 } // namespace __iter_move 85 86 inline namespace __cpo { 87 inline constexpr auto iter_move = __iter_move::__fn{}; 88 } // namespace __cpo 89 } // namespace ranges 90 91 template <__dereferenceable _Tp> 92 requires requires(_Tp& __t) { 93 { ranges::iter_move(__t) } -> __can_reference; 94 } 95 using iter_rvalue_reference_t = decltype(ranges::iter_move(std::declval<_Tp&>())); 96 97 #endif // _LIBCPP_STD_VER >= 20 98 99 _LIBCPP_END_NAMESPACE_STD 100 101 _LIBCPP_POP_MACROS 102 103 #endif // _LIBCPP___ITERATOR_ITER_MOVE_H 104