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 = 42 __class_or_enum<remove_cvref_t<_Tp>> && 43 requires (_Tp&& __t) { 44 // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap 45 iter_move(std::forward<_Tp>(__t)); 46 }; 47 48 template<class _Tp> 49 concept __move_deref = 50 !__unqualified_iter_move<_Tp> && 51 requires (_Tp&& __t) { 52 *__t; 53 requires is_lvalue_reference_v<decltype(*__t)>; 54 }; 55 56 template<class _Tp> 57 concept __just_deref = 58 !__unqualified_iter_move<_Tp> && 59 !__move_deref<_Tp> && 60 requires (_Tp&& __t) { 61 *__t; 62 requires (!is_lvalue_reference_v<decltype(*__t)>); 63 }; 64 65 // [iterator.cust.move] 66 67 struct __fn { 68 // NOLINTBEGIN(libcpp-robust-against-adl) iter_move ADL calls should only be made through ranges::iter_move 69 template<class _Ip> 70 requires __unqualified_iter_move<_Ip> 71 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const 72 noexcept(noexcept(iter_move(std::forward<_Ip>(__i)))) 73 { 74 return iter_move(std::forward<_Ip>(__i)); 75 } 76 // NOLINTEND(libcpp-robust-against-adl) 77 78 template<class _Ip> 79 requires __move_deref<_Ip> 80 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 81 noexcept(noexcept(std::move(*std::forward<_Ip>(__i)))) 82 -> decltype( std::move(*std::forward<_Ip>(__i))) 83 { return std::move(*std::forward<_Ip>(__i)); } 84 85 template<class _Ip> 86 requires __just_deref<_Ip> 87 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 88 noexcept(noexcept(*std::forward<_Ip>(__i))) 89 -> decltype( *std::forward<_Ip>(__i)) 90 { return *std::forward<_Ip>(__i); } 91 }; 92 } // namespace __iter_move 93 94 inline namespace __cpo { 95 inline constexpr auto iter_move = __iter_move::__fn{}; 96 } // namespace __cpo 97 } // namespace ranges 98 99 template<__dereferenceable _Tp> 100 requires requires(_Tp& __t) { { ranges::iter_move(__t) } -> __can_reference; } 101 using iter_rvalue_reference_t = decltype(ranges::iter_move(std::declval<_Tp&>())); 102 103 #endif // _LIBCPP_STD_VER >= 20 104 105 _LIBCPP_END_NAMESPACE_STD 106 107 _LIBCPP_POP_MACROS 108 109 #endif // _LIBCPP___ITERATOR_ITER_MOVE_H 110