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_BEGIN_NAMESPACE_STD
27
28#if _LIBCPP_STD_VER > 17
29
30// [iterator.cust.move]
31
32namespace ranges {
33namespace __iter_move {
34
35void iter_move();
36
37template <class _Tp>
38concept __unqualified_iter_move =
39  __class_or_enum<remove_cvref_t<_Tp>> &&
40  requires (_Tp&& __t) {
41    // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap
42    iter_move(std::forward<_Tp>(__t));
43  };
44
45template<class _Tp>
46concept __move_deref =
47  !__unqualified_iter_move<_Tp> &&
48  requires (_Tp&& __t) {
49    *__t;
50    requires is_lvalue_reference_v<decltype(*__t)>;
51  };
52
53template<class _Tp>
54concept __just_deref =
55  !__unqualified_iter_move<_Tp> &&
56  !__move_deref<_Tp> &&
57  requires (_Tp&& __t) {
58    *__t;
59    requires (!is_lvalue_reference_v<decltype(*__t)>);
60  };
61
62// [iterator.cust.move]
63
64struct __fn {
65  // NOLINTBEGIN(libcpp-robust-against-adl) iter_move ADL calls should only be made through ranges::iter_move
66  template<class _Ip>
67    requires __unqualified_iter_move<_Ip>
68  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const
69    noexcept(noexcept(iter_move(std::forward<_Ip>(__i))))
70  {
71    return iter_move(std::forward<_Ip>(__i));
72  }
73  // NOLINTEND(libcpp-robust-against-adl)
74
75  template<class _Ip>
76    requires __move_deref<_Ip>
77  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const
78    noexcept(noexcept(std::move(*std::forward<_Ip>(__i))))
79    -> decltype(      std::move(*std::forward<_Ip>(__i)))
80    { return          std::move(*std::forward<_Ip>(__i)); }
81
82  template<class _Ip>
83    requires __just_deref<_Ip>
84  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const
85    noexcept(noexcept(*std::forward<_Ip>(__i)))
86    -> decltype(      *std::forward<_Ip>(__i))
87    { return          *std::forward<_Ip>(__i); }
88};
89} // namespace __iter_move
90
91inline namespace __cpo {
92  inline constexpr auto iter_move = __iter_move::__fn{};
93} // namespace __cpo
94} // namespace ranges
95
96template<__dereferenceable _Tp>
97  requires requires(_Tp& __t) { { ranges::iter_move(__t) } -> __can_reference; }
98using iter_rvalue_reference_t = decltype(ranges::iter_move(std::declval<_Tp&>()));
99
100#endif // _LIBCPP_STD_VER > 17
101
102_LIBCPP_END_NAMESPACE_STD
103
104#endif // _LIBCPP___ITERATOR_ITER_MOVE_H
105