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 <__iterator/iterator_traits.h> 19 #include <__memory/destruct_n.h> 20 #include <__memory/temporary_buffer.h> 21 #include <__memory/unique_ptr.h> 22 #include <__type_traits/is_trivially_copy_assignable.h> 23 #include <__utility/move.h> 24 #include <__utility/pair.h> 25 #include <new> 26 27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 28 # pragma GCC system_header 29 #endif 30 31 _LIBCPP_BEGIN_NAMESPACE_STD 32 33 template <class _AlgPolicy, class _Compare, class _BidirectionalIterator> 34 _LIBCPP_HIDE_FROM_ABI 35 void __insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterator __last1, 36 typename iterator_traits<_BidirectionalIterator>::value_type* __first2, _Compare __comp) { 37 using _Ops = _IterOps<_AlgPolicy>; 38 39 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type; 40 if (__first1 != __last1) { 41 __destruct_n __d(0); 42 unique_ptr<value_type, __destruct_n&> __h(__first2, __d); 43 value_type* __last2 = __first2; 44 ::new ((void*)__last2) value_type(_Ops::__iter_move(__first1)); 45 __d.template __incr<value_type>(); 46 for (++__last2; ++__first1 != __last1; ++__last2) { 47 value_type* __j2 = __last2; 48 value_type* __i2 = __j2; 49 if (__comp(*__first1, *--__i2)) { 50 ::new ((void*)__j2) value_type(std::move(*__i2)); 51 __d.template __incr<value_type>(); 52 for (--__j2; __i2 != __first2 && __comp(*__first1, *--__i2); --__j2) 53 *__j2 = std::move(*__i2); 54 *__j2 = _Ops::__iter_move(__first1); 55 } else { 56 ::new ((void*)__j2) value_type(_Ops::__iter_move(__first1)); 57 __d.template __incr<value_type>(); 58 } 59 } 60 __h.release(); 61 } 62 } 63 64 template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2> 65 _LIBCPP_HIDE_FROM_ABI void 66 __merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1, 67 _InputIterator2 __first2, _InputIterator2 __last2, 68 typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp) 69 { 70 using _Ops = _IterOps<_AlgPolicy>; 71 72 typedef typename iterator_traits<_InputIterator1>::value_type value_type; 73 __destruct_n __d(0); 74 unique_ptr<value_type, __destruct_n&> __h(__result, __d); 75 for (; true; ++__result) 76 { 77 if (__first1 == __last1) 78 { 79 for (; __first2 != __last2; ++__first2, (void) ++__result, __d.template __incr<value_type>()) 80 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2)); 81 __h.release(); 82 return; 83 } 84 if (__first2 == __last2) 85 { 86 for (; __first1 != __last1; ++__first1, (void) ++__result, __d.template __incr<value_type>()) 87 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1)); 88 __h.release(); 89 return; 90 } 91 if (__comp(*__first2, *__first1)) 92 { 93 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2)); 94 __d.template __incr<value_type>(); 95 ++__first2; 96 } 97 else 98 { 99 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1)); 100 __d.template __incr<value_type>(); 101 ++__first1; 102 } 103 } 104 } 105 106 template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator> 107 _LIBCPP_HIDE_FROM_ABI void 108 __merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1, 109 _InputIterator2 __first2, _InputIterator2 __last2, 110 _OutputIterator __result, _Compare __comp) 111 { 112 using _Ops = _IterOps<_AlgPolicy>; 113 114 for (; __first1 != __last1; ++__result) 115 { 116 if (__first2 == __last2) 117 { 118 for (; __first1 != __last1; ++__first1, (void) ++__result) 119 *__result = _Ops::__iter_move(__first1); 120 return; 121 } 122 if (__comp(*__first2, *__first1)) 123 { 124 *__result = _Ops::__iter_move(__first2); 125 ++__first2; 126 } 127 else 128 { 129 *__result = _Ops::__iter_move(__first1); 130 ++__first1; 131 } 132 } 133 for (; __first2 != __last2; ++__first2, (void) ++__result) 134 *__result = _Ops::__iter_move(__first2); 135 } 136 137 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 138 void 139 __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp, 140 typename iterator_traits<_RandomAccessIterator>::difference_type __len, 141 typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size); 142 143 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 144 void 145 __stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp, 146 typename iterator_traits<_RandomAccessIterator>::difference_type __len, 147 typename iterator_traits<_RandomAccessIterator>::value_type* __first2) 148 { 149 using _Ops = _IterOps<_AlgPolicy>; 150 151 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type; 152 switch (__len) 153 { 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 { 164 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1)); 165 __d.template __incr<value_type>(); 166 ++__first2; 167 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1)); 168 } 169 else 170 { 171 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1)); 172 __d.template __incr<value_type>(); 173 ++__first2; 174 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1)); 175 } 176 __h2.release(); 177 return; 178 } 179 if (__len <= 8) 180 { 181 std::__insertion_sort_move<_AlgPolicy, _Compare>(__first1, __last1, __first2, __comp); 182 return; 183 } 184 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2; 185 _RandomAccessIterator __m = __first1 + __l2; 186 std::__stable_sort<_AlgPolicy, _Compare>(__first1, __m, __comp, __l2, __first2, __l2); 187 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2); 188 std::__merge_move_construct<_AlgPolicy, _Compare>(__first1, __m, __m, __last1, __first2, __comp); 189 } 190 191 template <class _Tp> 192 struct __stable_sort_switch 193 { 194 static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value; 195 }; 196 197 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 198 void 199 __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp, 200 typename iterator_traits<_RandomAccessIterator>::difference_type __len, 201 typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size) 202 { 203 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type; 204 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type; 205 switch (__len) 206 { 207 case 0: 208 case 1: 209 return; 210 case 2: 211 if (__comp(*--__last, *__first)) 212 _IterOps<_AlgPolicy>::iter_swap(__first, __last); 213 return; 214 } 215 if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value)) 216 { 217 std::__insertion_sort<_AlgPolicy, _Compare>(__first, __last, __comp); 218 return; 219 } 220 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2; 221 _RandomAccessIterator __m = __first + __l2; 222 if (__len <= __buff_size) 223 { 224 __destruct_n __d(0); 225 unique_ptr<value_type, __destruct_n&> __h2(__buff, __d); 226 std::__stable_sort_move<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff); 227 __d.__set(__l2, (value_type*)nullptr); 228 std::__stable_sort_move<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff + __l2); 229 __d.__set(__len, (value_type*)nullptr); 230 std::__merge_move_assign<_AlgPolicy, _Compare>( 231 __buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp); 232 // _VSTD::__merge<_Compare>(move_iterator<value_type*>(__buff), 233 // move_iterator<value_type*>(__buff + __l2), 234 // move_iterator<_RandomAccessIterator>(__buff + __l2), 235 // move_iterator<_RandomAccessIterator>(__buff + __len), 236 // __first, __comp); 237 return; 238 } 239 std::__stable_sort<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff, __buff_size); 240 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size); 241 std::__inplace_merge<_AlgPolicy>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size); 242 } 243 244 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare> 245 inline _LIBCPP_HIDE_FROM_ABI 246 void __stable_sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) { 247 using value_type = typename iterator_traits<_RandomAccessIterator>::value_type; 248 using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type; 249 250 difference_type __len = __last - __first; 251 pair<value_type*, ptrdiff_t> __buf(0, 0); 252 unique_ptr<value_type, __return_temporary_buffer> __h; 253 if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value)) { 254 // TODO: Remove the use of std::get_temporary_buffer 255 _LIBCPP_SUPPRESS_DEPRECATED_PUSH 256 __buf = std::get_temporary_buffer<value_type>(__len); 257 _LIBCPP_SUPPRESS_DEPRECATED_POP 258 __h.reset(__buf.first); 259 } 260 261 std::__stable_sort<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __last, __comp, __len, __buf.first, __buf.second); 262 } 263 264 template <class _RandomAccessIterator, class _Compare> 265 inline _LIBCPP_HIDE_FROM_ABI 266 void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { 267 std::__stable_sort_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp); 268 } 269 270 template <class _RandomAccessIterator> 271 inline _LIBCPP_HIDE_FROM_ABI 272 void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last) { 273 std::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); 274 } 275 276 _LIBCPP_END_NAMESPACE_STD 277 278 #endif // _LIBCPP___ALGORITHM_STABLE_SORT_H 279