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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_ROTATE_H
10#define _LIBCPP___ALGORITHM_ROTATE_H
11
12#include <__algorithm/copy.h>
13#include <__algorithm/copy_backward.h>
14#include <__algorithm/iterator_operations.h>
15#include <__algorithm/move.h>
16#include <__algorithm/move_backward.h>
17#include <__algorithm/swap_ranges.h>
18#include <__config>
19#include <__cstddef/size_t.h>
20#include <__fwd/bit_reference.h>
21#include <__iterator/iterator_traits.h>
22#include <__memory/construct_at.h>
23#include <__memory/pointer_traits.h>
24#include <__type_traits/is_constant_evaluated.h>
25#include <__type_traits/is_trivially_assignable.h>
26#include <__utility/move.h>
27#include <__utility/pair.h>
28
29#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
30# pragma GCC system_header
31#endif
32
33_LIBCPP_PUSH_MACROS
34#include <__undef_macros>
35
36_LIBCPP_BEGIN_NAMESPACE_STD
37
38template <class _AlgPolicy, class _ForwardIterator>
39_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
40__rotate_left(_ForwardIterator __first, _ForwardIterator __last) {
41 typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
42 using _Ops = _IterOps<_AlgPolicy>;
43
44 value_type __tmp = _Ops::__iter_move(__first);
45 _ForwardIterator __lm1 = std::__move<_AlgPolicy>(_Ops::next(__first), __last, __first).second;
46 *__lm1 = std::move(__tmp);
47 return __lm1;
48}
49
50template <class _AlgPolicy, class _BidirectionalIterator>
51_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator
52__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last) {
53 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
54 using _Ops = _IterOps<_AlgPolicy>;
55
56 _BidirectionalIterator __lm1 = _Ops::prev(__last);
57 value_type __tmp = _Ops::__iter_move(__lm1);
58 _BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last)).second;
59 *__first = std::move(__tmp);
60 return __fp1;
61}
62
63template <class _AlgPolicy, class _ForwardIterator>
64_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _ForwardIterator
65__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
66 _ForwardIterator __i = __middle;
67 while (true) {
68 _IterOps<_AlgPolicy>::iter_swap(__first, __i);
69 ++__first;
70 if (++__i == __last)
71 break;
72 if (__first == __middle)
73 __middle = __i;
74 }
75 _ForwardIterator __r = __first;
76 if (__first != __middle) {
77 __i = __middle;
78 while (true) {
79 _IterOps<_AlgPolicy>::iter_swap(__first, __i);
80 ++__first;
81 if (++__i == __last) {
82 if (__first == __middle)
83 break;
84 __i = __middle;
85 } else if (__first == __middle)
86 __middle = __i;
87 }
88 }
89 return __r;
90}
91
92template <typename _Integral>
93inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _Integral __algo_gcd(_Integral __x, _Integral __y) {
94 do {
95 _Integral __t = __x % __y;
96 __x = __y;
97 __y = __t;
98 } while (__y);
99 return __x;
100}
101
102template <class _AlgPolicy, typename _RandomAccessIterator>
103_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _RandomAccessIterator
104__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) {
105 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
106 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
107 using _Ops = _IterOps<_AlgPolicy>;
108
109 const difference_type __m1 = __middle - __first;
110 const difference_type __m2 = _Ops::distance(__middle, __last);
111 if (__m1 == __m2) {
112 std::__swap_ranges<_AlgPolicy>(__first, __middle, __middle, __last);
113 return __middle;
114 }
115 const difference_type __g = std::__algo_gcd(__m1, __m2);
116 for (_RandomAccessIterator __p = __first + __g; __p != __first;) {
117 value_type __t(_Ops::__iter_move(--__p));
118 _RandomAccessIterator __p1 = __p;
119 _RandomAccessIterator __p2 = __p1 + __m1;
120 do {
121 *__p1 = _Ops::__iter_move(__p2);
122 __p1 = __p2;
123 const difference_type __d = _Ops::distance(__p2, __last);
124 if (__m1 < __d)
125 __p2 += __m1;
126 else
127 __p2 = __first + (__m1 - __d);
128 } while (__p2 != __p);
129 *__p1 = std::move(__t);
130 }
131 return __first + __m2;
132}
133
134template <class _AlgPolicy, class _ForwardIterator>
135inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
136__rotate_impl(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, std::forward_iterator_tag) {
137 typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
138 if (is_trivially_move_assignable<value_type>::value) {
139 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
140 return std::__rotate_left<_AlgPolicy>(__first, __last);
141 }
142 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
143}
144
145template <class _AlgPolicy, class _BidirectionalIterator>
146inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator __rotate_impl(
147 _BidirectionalIterator __first,
148 _BidirectionalIterator __middle,
149 _BidirectionalIterator __last,
150 bidirectional_iterator_tag) {
151 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
152 if (is_trivially_move_assignable<value_type>::value) {
153 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
154 return std::__rotate_left<_AlgPolicy>(__first, __last);
155 if (_IterOps<_AlgPolicy>::next(__middle) == __last)
156 return std::__rotate_right<_AlgPolicy>(__first, __last);
157 }
158 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
159}
160
161template <class _AlgPolicy, class _RandomAccessIterator>
162inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _RandomAccessIterator __rotate_impl(
163 _RandomAccessIterator __first,
164 _RandomAccessIterator __middle,
165 _RandomAccessIterator __last,
166 random_access_iterator_tag) {
167 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
168 if (is_trivially_move_assignable<value_type>::value) {
169 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
170 return std::__rotate_left<_AlgPolicy>(__first, __last);
171 if (_IterOps<_AlgPolicy>::next(__middle) == __last)
172 return std::__rotate_right<_AlgPolicy>(__first, __last);
173 return std::__rotate_gcd<_AlgPolicy>(__first, __middle, __last);
174 }
175 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
176}
177
178template <class _AlgPolicy, class _Iterator, class _Sentinel>
179_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iterator, _Iterator>
180__rotate(_Iterator __first, _Iterator __middle, _Sentinel __last) {
181 using _Ret = pair<_Iterator, _Iterator>;
182 _Iterator __last_iter = _IterOps<_AlgPolicy>::next(__middle, __last);
183
184 if (__first == __middle)
185 return _Ret(__last_iter, __last_iter);
186 if (__middle == __last)
187 return _Ret(std::move(__first), std::move(__last_iter));
188
189 using _IterCategory = typename _IterOps<_AlgPolicy>::template __iterator_category<_Iterator>;
190 auto __result = std::__rotate_impl<_AlgPolicy>(std::move(__first), std::move(__middle), __last_iter, _IterCategory());
191
192 return _Ret(std::move(__result), std::move(__last_iter));
193}
194
195template <class, class _Cp>
196_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cp, false>, __bit_iterator<_Cp, false> >
197__rotate(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __middle, __bit_iterator<_Cp, false> __last) {
198 using _I1 = __bit_iterator<_Cp, false>;
199 using difference_type = typename _I1::difference_type;
200 difference_type __d1 = __middle - __first;
201 difference_type __d2 = __last - __middle;
202 _I1 __r = __first + __d2;
203 while (__d1 != 0 && __d2 != 0) {
204 if (__d1 <= __d2) {
205 if (__d1 <= __bit_array<_Cp>::capacity()) {
206 __bit_array<_Cp> __b(__d1);
207 std::copy(__first, __middle, __b.begin());
208 std::copy(__b.begin(), __b.end(), std::copy(__middle, __last, __first));
209 break;
210 } else {
211 __bit_iterator<_Cp, false> __mp = std::swap_ranges(__first, __middle, __middle);
212 __first = __middle;
213 __middle = __mp;
214 __d2 -= __d1;
215 }
216 } else {
217 if (__d2 <= __bit_array<_Cp>::capacity()) {
218 __bit_array<_Cp> __b(__d2);
219 std::copy(__middle, __last, __b.begin());
220 std::copy_backward(__b.begin(), __b.end(), std::copy_backward(__first, __middle, __last));
221 break;
222 } else {
223 __bit_iterator<_Cp, false> __mp = __first + __d2;
224 std::swap_ranges(__first, __mp, __middle);
225 __first = __mp;
226 __d1 -= __d2;
227 }
228 }
229 }
230 return std::make_pair(__r, __last);
231}
232
233template <class _ForwardIterator>
234inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
235rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
236 return std::__rotate<_ClassicAlgPolicy>(std::move(__first), std::move(__middle), std::move(__last)).first;
237}
238
239_LIBCPP_END_NAMESPACE_STD
240
241_LIBCPP_POP_MACROS
242
243#endif // _LIBCPP___ALGORITHM_ROTATE_H