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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_SWAP_H
11#define _LIBCPP___ITERATOR_ITER_SWAP_H
12
13#include <__concepts/class_or_enum.h>
14#include <__concepts/swappable.h>
15#include <__config>
16#include <__iterator/concepts.h>
17#include <__iterator/iter_move.h>
18#include <__iterator/iterator_traits.h>
19#include <__iterator/readable_traits.h>
20#include <__type_traits/remove_cvref.h>
21#include <__utility/declval.h>
22#include <__utility/forward.h>
23#include <__utility/move.h>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32_LIBCPP_BEGIN_NAMESPACE_STD
33
34#if _LIBCPP_STD_VER >= 20
35
36// [iter.cust.swap]
37
38namespace ranges {
39namespace __iter_swap {
40template <class _I1, class _I2>
41void iter_swap(_I1, _I2) = delete;
42
43template <class _T1, class _T2>
44concept __unqualified_iter_swap =
45 (__class_or_enum<remove_cvref_t<_T1>> || __class_or_enum<remove_cvref_t<_T2>>) && requires(_T1&& __x, _T2&& __y) {
46 // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap
47 iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y));
48 };
49
50template <class _T1, class _T2>
51concept __readable_swappable =
52 indirectly_readable<_T1> && indirectly_readable<_T2> &&
53 swappable_with<iter_reference_t<_T1>, iter_reference_t<_T2>>;
54
55struct __fn {
56 // NOLINTBEGIN(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap
57 template <class _T1, class _T2>
58 requires __unqualified_iter_swap<_T1, _T2>
59 _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
60 noexcept(noexcept(iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y)))) {
61 (void)iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y));
62 }
63 // NOLINTEND(libcpp-robust-against-adl)
64
65 template <class _T1, class _T2>
66 requires(!__unqualified_iter_swap<_T1, _T2>) && __readable_swappable<_T1, _T2>
67 _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
68 noexcept(noexcept(ranges::swap(*std::forward<_T1>(__x), *std::forward<_T2>(__y)))) {
69 ranges::swap(*std::forward<_T1>(__x), *std::forward<_T2>(__y));
70 }
71
72 template <class _T1, class _T2>
73 requires(!__unqualified_iter_swap<_T1, _T2> && //
74 !__readable_swappable<_T1, _T2>) && //
75 indirectly_movable_storable<_T1, _T2> && //
76 indirectly_movable_storable<_T2, _T1>
77 _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
78 noexcept(noexcept(iter_value_t<_T2>(ranges::iter_move(__y))) && //
79 noexcept(*__y = ranges::iter_move(__x)) && //
80 noexcept(*std::forward<_T1>(__x) = std::declval<iter_value_t<_T2>>())) {
81 iter_value_t<_T2> __old(ranges::iter_move(__y));
82 *__y = ranges::iter_move(__x);
83 *std::forward<_T1>(__x) = std::move(__old);
84 }
85};
86} // namespace __iter_swap
87
88inline namespace __cpo {
89inline constexpr auto iter_swap = __iter_swap::__fn{};
90} // namespace __cpo
91} // namespace ranges
92
93template <class _I1, class _I2 = _I1>
94concept indirectly_swappable =
95 indirectly_readable<_I1> && indirectly_readable<_I2> && requires(const _I1 __i1, const _I2 __i2) {
96 ranges::iter_swap(__i1, __i1);
97 ranges::iter_swap(__i2, __i2);
98 ranges::iter_swap(__i1, __i2);
99 ranges::iter_swap(__i2, __i1);
100 };
101
102#endif // _LIBCPP_STD_VER >= 20
103
104_LIBCPP_END_NAMESPACE_STD
105
106_LIBCPP_POP_MACROS
107
108#endif // _LIBCPP___ITERATOR_ITER_SWAP_H