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
109