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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___CXX03___ALGORITHM_STABLE_SORT_H
10#define _LIBCPP___CXX03___ALGORITHM_STABLE_SORT_H
11
12#include <__cxx03/__algorithm/comp.h>
13#include <__cxx03/__algorithm/comp_ref_type.h>
14#include <__cxx03/__algorithm/inplace_merge.h>
15#include <__cxx03/__algorithm/iterator_operations.h>
16#include <__cxx03/__algorithm/sort.h>
17#include <__cxx03/__config>
18#include <__cxx03/__debug_utils/strict_weak_ordering_check.h>
19#include <__cxx03/__iterator/iterator_traits.h>
20#include <__cxx03/__memory/destruct_n.h>
21#include <__cxx03/__memory/temporary_buffer.h>
22#include <__cxx03/__memory/unique_ptr.h>
23#include <__cxx03/__type_traits/is_trivially_assignable.h>
24#include <__cxx03/__utility/move.h>
25#include <__cxx03/__utility/pair.h>
26#include <__cxx03/new>
27
28#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
29# pragma GCC system_header
30#endif
31
32_LIBCPP_PUSH_MACROS
33#include <__cxx03/__undef_macros>
34
35_LIBCPP_BEGIN_NAMESPACE_STD
36
37template <class _AlgPolicy, class _Compare, class _BidirectionalIterator>
38_LIBCPP_HIDE_FROM_ABI void __insertion_sort_move(
39 _BidirectionalIterator __first1,
40 _BidirectionalIterator __last1,
41 typename iterator_traits<_BidirectionalIterator>::value_type* __first2,
42 _Compare __comp) {
43 using _Ops = _IterOps<_AlgPolicy>;
44
45 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
46 if (__first1 != __last1) {
47 __destruct_n __d(0);
48 unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
49 value_type* __last2 = __first2;
50 ::new ((void*)__last2) value_type(_Ops::__iter_move(__first1));
51 __d.template __incr<value_type>();
52 for (++__last2; ++__first1 != __last1; ++__last2) {
53 value_type* __j2 = __last2;
54 value_type* __i2 = __j2;
55 if (__comp(*__first1, *--__i2)) {
56 ::new ((void*)__j2) value_type(std::move(*__i2));
57 __d.template __incr<value_type>();
58 for (--__j2; __i2 != __first2 && __comp(*__first1, *--__i2); --__j2)
59 *__j2 = std::move(*__i2);
60 *__j2 = _Ops::__iter_move(__first1);
61 } else {
62 ::new ((void*)__j2) value_type(_Ops::__iter_move(__first1));
63 __d.template __incr<value_type>();
64 }
65 }
66 __h.release();
67 }
68}
69
70template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2>
71_LIBCPP_HIDE_FROM_ABI void __merge_move_construct(
72 _InputIterator1 __first1,
73 _InputIterator1 __last1,
74 _InputIterator2 __first2,
75 _InputIterator2 __last2,
76 typename iterator_traits<_InputIterator1>::value_type* __result,
77 _Compare __comp) {
78 using _Ops = _IterOps<_AlgPolicy>;
79
80 typedef typename iterator_traits<_InputIterator1>::value_type value_type;
81 __destruct_n __d(0);
82 unique_ptr<value_type, __destruct_n&> __h(__result, __d);
83 for (; true; ++__result) {
84 if (__first1 == __last1) {
85 for (; __first2 != __last2; ++__first2, (void)++__result, __d.template __incr<value_type>())
86 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2));
87 __h.release();
88 return;
89 }
90 if (__first2 == __last2) {
91 for (; __first1 != __last1; ++__first1, (void)++__result, __d.template __incr<value_type>())
92 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1));
93 __h.release();
94 return;
95 }
96 if (__comp(*__first2, *__first1)) {
97 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2));
98 __d.template __incr<value_type>();
99 ++__first2;
100 } else {
101 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1));
102 __d.template __incr<value_type>();
103 ++__first1;
104 }
105 }
106}
107
108template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
109_LIBCPP_HIDE_FROM_ABI void __merge_move_assign(
110 _InputIterator1 __first1,
111 _InputIterator1 __last1,
112 _InputIterator2 __first2,
113 _InputIterator2 __last2,
114 _OutputIterator __result,
115 _Compare __comp) {
116 using _Ops = _IterOps<_AlgPolicy>;
117
118 for (; __first1 != __last1; ++__result) {
119 if (__first2 == __last2) {
120 for (; __first1 != __last1; ++__first1, (void)++__result)
121 *__result = _Ops::__iter_move(__first1);
122 return;
123 }
124 if (__comp(*__first2, *__first1)) {
125 *__result = _Ops::__iter_move(__first2);
126 ++__first2;
127 } else {
128 *__result = _Ops::__iter_move(__first1);
129 ++__first1;
130 }
131 }
132 for (; __first2 != __last2; ++__first2, (void)++__result)
133 *__result = _Ops::__iter_move(__first2);
134}
135
136template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
137void __stable_sort(_RandomAccessIterator __first,
138 _RandomAccessIterator __last,
139 _Compare __comp,
140 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
141 typename iterator_traits<_RandomAccessIterator>::value_type* __buff,
142 ptrdiff_t __buff_size);
143
144template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
145void __stable_sort_move(_RandomAccessIterator __first1,
146 _RandomAccessIterator __last1,
147 _Compare __comp,
148 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
149 typename iterator_traits<_RandomAccessIterator>::value_type* __first2) {
150 using _Ops = _IterOps<_AlgPolicy>;
151
152 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
153 switch (__len) {
154 case 0:
155 return;
156 case 1:
157 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
158 return;
159 case 2:
160 __destruct_n __d(0);
161 unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
162 if (__comp(*--__last1, *__first1)) {
163 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1));
164 __d.template __incr<value_type>();
165 ++__first2;
166 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
167 } else {
168 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
169 __d.template __incr<value_type>();
170 ++__first2;
171 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1));
172 }
173 __h2.release();
174 return;
175 }
176 if (__len <= 8) {
177 std::__insertion_sort_move<_AlgPolicy, _Compare>(__first1, __last1, __first2, __comp);
178 return;
179 }
180 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
181 _RandomAccessIterator __m = __first1 + __l2;
182 std::__stable_sort<_AlgPolicy, _Compare>(__first1, __m, __comp, __l2, __first2, __l2);
183 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
184 std::__merge_move_construct<_AlgPolicy, _Compare>(__first1, __m, __m, __last1, __first2, __comp);
185}
186
187template <class _Tp>
188struct __stable_sort_switch {
189 static const unsigned value = 128 * is_trivially_copy_assignable<_Tp>::value;
190};
191
192template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
193void __stable_sort(_RandomAccessIterator __first,
194 _RandomAccessIterator __last,
195 _Compare __comp,
196 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
197 typename iterator_traits<_RandomAccessIterator>::value_type* __buff,
198 ptrdiff_t __buff_size) {
199 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
200 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
201 switch (__len) {
202 case 0:
203 case 1:
204 return;
205 case 2:
206 if (__comp(*--__last, *__first))
207 _IterOps<_AlgPolicy>::iter_swap(__first, __last);
208 return;
209 }
210 if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value)) {
211 std::__insertion_sort<_AlgPolicy, _Compare>(__first, __last, __comp);
212 return;
213 }
214 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
215 _RandomAccessIterator __m = __first + __l2;
216 if (__len <= __buff_size) {
217 __destruct_n __d(0);
218 unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
219 std::__stable_sort_move<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff);
220 __d.__set(__l2, (value_type*)nullptr);
221 std::__stable_sort_move<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
222 __d.__set(__len, (value_type*)nullptr);
223 std::__merge_move_assign<_AlgPolicy, _Compare>(
224 __buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
225 // std::__merge<_Compare>(move_iterator<value_type*>(__buff),
226 // move_iterator<value_type*>(__buff + __l2),
227 // move_iterator<_RandomAccessIterator>(__buff + __l2),
228 // move_iterator<_RandomAccessIterator>(__buff + __len),
229 // __first, __comp);
230 return;
231 }
232 std::__stable_sort<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
233 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
234 std::__inplace_merge<_AlgPolicy>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
235}
236
237template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
238inline _LIBCPP_HIDE_FROM_ABI void
239__stable_sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
240 using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
241 using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
242
243 difference_type __len = __last - __first;
244 pair<value_type*, ptrdiff_t> __buf(0, 0);
245 unique_ptr<value_type, __return_temporary_buffer> __h;
246 if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value)) {
247 // TODO: Remove the use of std::get_temporary_buffer
248 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
249 __buf = std::get_temporary_buffer<value_type>(__len);
250 _LIBCPP_SUPPRESS_DEPRECATED_POP
251 __h.reset(__buf.first);
252 }
253
254 std::__stable_sort<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __last, __comp, __len, __buf.first, __buf.second);
255 std::__check_strict_weak_ordering_sorted(__first, __last, __comp);
256}
257
258template <class _RandomAccessIterator, class _Compare>
259inline _LIBCPP_HIDE_FROM_ABI void
260stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
261 std::__stable_sort_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
262}
263
264template <class _RandomAccessIterator>
265inline _LIBCPP_HIDE_FROM_ABI void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last) {
266 std::stable_sort(__first, __last, __less<>());
267}
268
269_LIBCPP_END_NAMESPACE_STD
270
271_LIBCPP_POP_MACROS
272
273#endif // _LIBCPP___CXX03___ALGORITHM_STABLE_SORT_H
274

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source code of libcxx/include/__cxx03/__algorithm/stable_sort.h