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
35namespace ranges {
36namespace __iter_move {
37
38void iter_move();
39
40template <class _Tp>
41concept __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
46template <class _Tp>
47concept __move_deref = !__unqualified_iter_move<_Tp> && requires(_Tp&& __t) {
48  *__t;
49  requires is_lvalue_reference_v<decltype(*__t)>;
50};
51
52template <class _Tp>
53concept __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
60struct __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
86inline namespace __cpo {
87inline constexpr auto iter_move = __iter_move::__fn{};
88} // namespace __cpo
89} // namespace ranges
90
91template <__dereferenceable _Tp>
92  requires requires(_Tp& __t) {
93    { ranges::iter_move(__t) } -> __can_reference;
94  }
95using 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