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_STABLE_SORT_H 10 #define _LIBCPP___ALGORITHM_STABLE_SORT_H 11 12 #include <__algorithm/comp.h> 13 #include <__algorithm/comp_ref_type.h> 14 #include <__algorithm/inplace_merge.h> 15 #include <__algorithm/iterator_operations.h> 16 #include <__algorithm/sort.h> 17 #include <__config> 18 #include <__debug_utils/strict_weak_ordering_check.h> 19 #include <__iterator/iterator_traits.h> 20 #include <__memory/destruct_n.h> 21 #include <__memory/temporary_buffer.h> 22 #include <__memory/unique_ptr.h> 23 #include <__type_traits/is_trivially_assignable.h> 24 #include <__utility/move.h> 25 #include <__utility/pair.h> 26 #include <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 <__undef_macros> 34 35 _LIBCPP_BEGIN_NAMESPACE_STD 36 37 template <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 70 template <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 } 107 108 template <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 } 135 136 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 137 void __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); 143 144 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 145 void __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 } 186 187 template <class _Tp> 188 struct __stable_sort_switch { 189 static const unsigned value = 128 * is_trivially_copy_assignable<_Tp>::value; 190 }; 191 192 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 193 void __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 } 236 237 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare> 238 inline _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 } 257 258 template <class _RandomAccessIterator, class _Compare> 259 inline _LIBCPP_HIDE_FROM_ABI void 260 stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { 261 std::__stable_sort_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp); 262 } 263 264 template <class _RandomAccessIterator> 265 inline _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___ALGORITHM_STABLE_SORT_H 274