1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___ALGORITHM_RANGES_SWAP_RANGES_H
10#define _LIBCPP___ALGORITHM_RANGES_SWAP_RANGES_H
11
12#include <__algorithm/in_in_result.h>
13#include <__algorithm/iterator_operations.h>
14#include <__algorithm/min.h>
15#include <__algorithm/swap_ranges.h>
16#include <__config>
17#include <__iterator/concepts.h>
18#include <__iterator/iter_swap.h>
19#include <__ranges/access.h>
20#include <__ranges/concepts.h>
21#include <__ranges/dangling.h>
22#include <__type_traits/is_same.h>
23#include <__utility/move.h>
24#include <__utility/pair.h>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27# pragma GCC system_header
28#endif
29
30_LIBCPP_PUSH_MACROS
31#include <__undef_macros>
32
33#if _LIBCPP_STD_VER >= 20
34
35_LIBCPP_BEGIN_NAMESPACE_STD
36
37namespace ranges {
38
39template <class _I1, class _I2>
40using swap_ranges_result = in_in_result<_I1, _I2>;
41
42struct __swap_ranges {
43 template <input_iterator _I1, sentinel_for<_I1> _S1, input_iterator _I2, sentinel_for<_I2> _S2>
44 requires indirectly_swappable<_I1, _I2>
45 _LIBCPP_HIDE_FROM_ABI constexpr swap_ranges_result<_I1, _I2>
46 operator()(_I1 __first1, _S1 __last1, _I2 __first2, _S2 __last2) const {
47 if constexpr (sized_sentinel_for<_I1, _S1> && sized_sentinel_for<_I2, _S2> &&
48 (random_access_iterator<_I1> || random_access_iterator<_I2> ||
49 (is_same_v<_I1, _S1> && is_same_v<_I2, _S2>))) {
50 auto __offset = std::min(__last1 - __first1, __last2 - __first2);
51
52 auto __ret = [&] {
53 if constexpr (random_access_iterator<_I1>)
54 return std::__swap_ranges<_RangeAlgPolicy>(__first1, __first1 + __offset, std::move(__first2));
55 else if constexpr (random_access_iterator<_I2>)
56 return std::__swap_ranges<_RangeAlgPolicy>(__first2, __first2 + __offset, std::move(__first1));
57 else if (__last2 - __first2 < __last1 - __first1) {
58 auto __reversed =
59 std::__swap_ranges<_RangeAlgPolicy>(std::move(__first2), std::move(__last2), std::move(__first1));
60 return std::pair<_I1, _I2>(std::move(__reversed.second), std::move(__reversed.first));
61 } else
62 return std::__swap_ranges<_RangeAlgPolicy>(std::move(__first1), std::move(__last1), std::move(__first2));
63 }();
64 return {std::move(__ret.first), std::move(__ret.second)};
65 } else {
66 while (__first1 != __last1 && __first2 != __last2) {
67 ranges::iter_swap(__first1, __first2);
68 ++__first1;
69 ++__first2;
70 }
71
72 return {std::move(__first1), std::move(__first2)};
73 }
74 }
75
76 template <input_range _R1, input_range _R2>
77 requires indirectly_swappable<iterator_t<_R1>, iterator_t<_R2>>
78 _LIBCPP_HIDE_FROM_ABI constexpr swap_ranges_result<borrowed_iterator_t<_R1>, borrowed_iterator_t<_R2>>
79 operator()(_R1&& __r1, _R2&& __r2) const {
80 return operator()(ranges::begin(__r1), ranges::end(__r1), ranges::begin(__r2), ranges::end(__r2));
81 }
82};
83
84inline namespace __cpo {
85inline constexpr auto swap_ranges = __swap_ranges{};
86} // namespace __cpo
87} // namespace ranges
88
89_LIBCPP_END_NAMESPACE_STD
90
91#endif // _LIBCPP_STD_VER >= 20
92
93_LIBCPP_POP_MACROS
94
95#endif // _LIBCPP___ALGORITHM_RANGES_SWAP_RANGES_H
96