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_SORT_H 10 #define _LIBCPP___ALGORITHM_SORT_H 11 12 #include <__config> 13 #include <__algorithm/comp.h> 14 #include <__algorithm/comp_ref_type.h> 15 #include <__algorithm/min_element.h> 16 #include <__algorithm/partial_sort.h> 17 #include <__algorithm/unwrap_iter.h> 18 #include <__utility/swap.h> 19 #include <memory> 20 #include <type_traits> // swap 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 #pragma GCC system_header 24 #endif 25 26 _LIBCPP_PUSH_MACROS 27 #include <__undef_macros> 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 // stable, 2-3 compares, 0-2 swaps 32 33 template <class _Compare, class _ForwardIterator> 34 _LIBCPP_CONSTEXPR_AFTER_CXX11 unsigned 35 __sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c) 36 { 37 unsigned __r = 0; 38 if (!__c(*__y, *__x)) // if x <= y 39 { 40 if (!__c(*__z, *__y)) // if y <= z 41 return __r; // x <= y && y <= z 42 // x <= y && y > z 43 swap(*__y, *__z); // x <= z && y < z 44 __r = 1; 45 if (__c(*__y, *__x)) // if x > y 46 { 47 swap(*__x, *__y); // x < y && y <= z 48 __r = 2; 49 } 50 return __r; // x <= y && y < z 51 } 52 if (__c(*__z, *__y)) // x > y, if y > z 53 { 54 swap(*__x, *__z); // x < y && y < z 55 __r = 1; 56 return __r; 57 } 58 swap(*__x, *__y); // x > y && y <= z 59 __r = 1; // x < y && x <= z 60 if (__c(*__z, *__y)) // if y > z 61 { 62 swap(*__y, *__z); // x <= y && y < z 63 __r = 2; 64 } 65 return __r; 66 } // x <= y && y <= z 67 68 // stable, 3-6 compares, 0-5 swaps 69 70 template <class _Compare, class _ForwardIterator> 71 unsigned 72 __sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3, 73 _ForwardIterator __x4, _Compare __c) 74 { 75 unsigned __r = _VSTD::__sort3<_Compare>(__x1, __x2, __x3, __c); 76 if (__c(*__x4, *__x3)) 77 { 78 swap(*__x3, *__x4); 79 ++__r; 80 if (__c(*__x3, *__x2)) 81 { 82 swap(*__x2, *__x3); 83 ++__r; 84 if (__c(*__x2, *__x1)) 85 { 86 swap(*__x1, *__x2); 87 ++__r; 88 } 89 } 90 } 91 return __r; 92 } 93 94 // stable, 4-10 compares, 0-9 swaps 95 96 template <class _Compare, class _ForwardIterator> 97 _LIBCPP_HIDDEN 98 unsigned 99 __sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3, 100 _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c) 101 { 102 unsigned __r = _VSTD::__sort4<_Compare>(__x1, __x2, __x3, __x4, __c); 103 if (__c(*__x5, *__x4)) 104 { 105 swap(*__x4, *__x5); 106 ++__r; 107 if (__c(*__x4, *__x3)) 108 { 109 swap(*__x3, *__x4); 110 ++__r; 111 if (__c(*__x3, *__x2)) 112 { 113 swap(*__x2, *__x3); 114 ++__r; 115 if (__c(*__x2, *__x1)) 116 { 117 swap(*__x1, *__x2); 118 ++__r; 119 } 120 } 121 } 122 } 123 return __r; 124 } 125 126 // Assumes size > 0 127 template <class _Compare, class _BidirectionalIterator> 128 _LIBCPP_CONSTEXPR_AFTER_CXX11 void 129 __selection_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) 130 { 131 _BidirectionalIterator __lm1 = __last; 132 for (--__lm1; __first != __lm1; ++__first) 133 { 134 _BidirectionalIterator __i = _VSTD::min_element<_BidirectionalIterator, 135 typename add_lvalue_reference<_Compare>::type> 136 (__first, __last, __comp); 137 if (__i != __first) 138 swap(*__first, *__i); 139 } 140 } 141 142 template <class _Compare, class _BidirectionalIterator> 143 void 144 __insertion_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) 145 { 146 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type; 147 if (__first != __last) 148 { 149 _BidirectionalIterator __i = __first; 150 for (++__i; __i != __last; ++__i) 151 { 152 _BidirectionalIterator __j = __i; 153 value_type __t(_VSTD::move(*__j)); 154 for (_BidirectionalIterator __k = __i; __k != __first && __comp(__t, *--__k); --__j) 155 *__j = _VSTD::move(*__k); 156 *__j = _VSTD::move(__t); 157 } 158 } 159 } 160 161 template <class _Compare, class _RandomAccessIterator> 162 void 163 __insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) 164 { 165 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type; 166 _RandomAccessIterator __j = __first+2; 167 _VSTD::__sort3<_Compare>(__first, __first+1, __j, __comp); 168 for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i) 169 { 170 if (__comp(*__i, *__j)) 171 { 172 value_type __t(_VSTD::move(*__i)); 173 _RandomAccessIterator __k = __j; 174 __j = __i; 175 do 176 { 177 *__j = _VSTD::move(*__k); 178 __j = __k; 179 } while (__j != __first && __comp(__t, *--__k)); 180 *__j = _VSTD::move(__t); 181 } 182 __j = __i; 183 } 184 } 185 186 template <class _Compare, class _RandomAccessIterator> 187 bool 188 __insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) 189 { 190 switch (__last - __first) 191 { 192 case 0: 193 case 1: 194 return true; 195 case 2: 196 if (__comp(*--__last, *__first)) 197 swap(*__first, *__last); 198 return true; 199 case 3: 200 _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp); 201 return true; 202 case 4: 203 _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp); 204 return true; 205 case 5: 206 _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp); 207 return true; 208 } 209 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type; 210 _RandomAccessIterator __j = __first+2; 211 _VSTD::__sort3<_Compare>(__first, __first+1, __j, __comp); 212 const unsigned __limit = 8; 213 unsigned __count = 0; 214 for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i) 215 { 216 if (__comp(*__i, *__j)) 217 { 218 value_type __t(_VSTD::move(*__i)); 219 _RandomAccessIterator __k = __j; 220 __j = __i; 221 do 222 { 223 *__j = _VSTD::move(*__k); 224 __j = __k; 225 } while (__j != __first && __comp(__t, *--__k)); 226 *__j = _VSTD::move(__t); 227 if (++__count == __limit) 228 return ++__i == __last; 229 } 230 __j = __i; 231 } 232 return true; 233 } 234 235 template <class _Compare, class _BidirectionalIterator> 236 void 237 __insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterator __last1, 238 typename iterator_traits<_BidirectionalIterator>::value_type* __first2, _Compare __comp) 239 { 240 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type; 241 if (__first1 != __last1) 242 { 243 __destruct_n __d(0); 244 unique_ptr<value_type, __destruct_n&> __h(__first2, __d); 245 value_type* __last2 = __first2; 246 ::new ((void*)__last2) value_type(_VSTD::move(*__first1)); 247 __d.template __incr<value_type>(); 248 for (++__last2; ++__first1 != __last1; ++__last2) 249 { 250 value_type* __j2 = __last2; 251 value_type* __i2 = __j2; 252 if (__comp(*__first1, *--__i2)) 253 { 254 ::new ((void*)__j2) value_type(_VSTD::move(*__i2)); 255 __d.template __incr<value_type>(); 256 for (--__j2; __i2 != __first2 && __comp(*__first1, *--__i2); --__j2) 257 *__j2 = _VSTD::move(*__i2); 258 *__j2 = _VSTD::move(*__first1); 259 } 260 else 261 { 262 ::new ((void*)__j2) value_type(_VSTD::move(*__first1)); 263 __d.template __incr<value_type>(); 264 } 265 } 266 __h.release(); 267 } 268 } 269 270 template <class _Compare, class _RandomAccessIterator> 271 void 272 __sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) 273 { 274 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type; 275 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type; 276 const difference_type __limit = is_trivially_copy_constructible<value_type>::value && 277 is_trivially_copy_assignable<value_type>::value ? 30 : 6; 278 while (true) 279 { 280 __restart: 281 difference_type __len = __last - __first; 282 switch (__len) 283 { 284 case 0: 285 case 1: 286 return; 287 case 2: 288 if (__comp(*--__last, *__first)) 289 swap(*__first, *__last); 290 return; 291 case 3: 292 _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp); 293 return; 294 case 4: 295 _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp); 296 return; 297 case 5: 298 _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp); 299 return; 300 } 301 if (__len <= __limit) 302 { 303 _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp); 304 return; 305 } 306 // __len > 5 307 _RandomAccessIterator __m = __first; 308 _RandomAccessIterator __lm1 = __last; 309 --__lm1; 310 unsigned __n_swaps; 311 { 312 difference_type __delta; 313 if (__len >= 1000) 314 { 315 __delta = __len/2; 316 __m += __delta; 317 __delta /= 2; 318 __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp); 319 } 320 else 321 { 322 __delta = __len/2; 323 __m += __delta; 324 __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp); 325 } 326 } 327 // *__m is median 328 // partition [__first, __m) < *__m and *__m <= [__m, __last) 329 // (this inhibits tossing elements equivalent to __m around unnecessarily) 330 _RandomAccessIterator __i = __first; 331 _RandomAccessIterator __j = __lm1; 332 // j points beyond range to be tested, *__m is known to be <= *__lm1 333 // The search going up is known to be guarded but the search coming down isn't. 334 // Prime the downward search with a guard. 335 if (!__comp(*__i, *__m)) // if *__first == *__m 336 { 337 // *__first == *__m, *__first doesn't go in first part 338 // manually guard downward moving __j against __i 339 while (true) 340 { 341 if (__i == --__j) 342 { 343 // *__first == *__m, *__m <= all other elements 344 // Parition instead into [__first, __i) == *__first and *__first < [__i, __last) 345 ++__i; // __first + 1 346 __j = __last; 347 if (!__comp(*__first, *--__j)) // we need a guard if *__first == *(__last-1) 348 { 349 while (true) 350 { 351 if (__i == __j) 352 return; // [__first, __last) all equivalent elements 353 if (__comp(*__first, *__i)) 354 { 355 swap(*__i, *__j); 356 ++__n_swaps; 357 ++__i; 358 break; 359 } 360 ++__i; 361 } 362 } 363 // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1 364 if (__i == __j) 365 return; 366 while (true) 367 { 368 while (!__comp(*__first, *__i)) 369 ++__i; 370 while (__comp(*__first, *--__j)) 371 ; 372 if (__i >= __j) 373 break; 374 swap(*__i, *__j); 375 ++__n_swaps; 376 ++__i; 377 } 378 // [__first, __i) == *__first and *__first < [__i, __last) 379 // The first part is sorted, sort the second part 380 // _VSTD::__sort<_Compare>(__i, __last, __comp); 381 __first = __i; 382 goto __restart; 383 } 384 if (__comp(*__j, *__m)) 385 { 386 swap(*__i, *__j); 387 ++__n_swaps; 388 break; // found guard for downward moving __j, now use unguarded partition 389 } 390 } 391 } 392 // It is known that *__i < *__m 393 ++__i; 394 // j points beyond range to be tested, *__m is known to be <= *__lm1 395 // if not yet partitioned... 396 if (__i < __j) 397 { 398 // known that *(__i - 1) < *__m 399 // known that __i <= __m 400 while (true) 401 { 402 // __m still guards upward moving __i 403 while (__comp(*__i, *__m)) 404 ++__i; 405 // It is now known that a guard exists for downward moving __j 406 while (!__comp(*--__j, *__m)) 407 ; 408 if (__i > __j) 409 break; 410 swap(*__i, *__j); 411 ++__n_swaps; 412 // It is known that __m != __j 413 // If __m just moved, follow it 414 if (__m == __i) 415 __m = __j; 416 ++__i; 417 } 418 } 419 // [__first, __i) < *__m and *__m <= [__i, __last) 420 if (__i != __m && __comp(*__m, *__i)) 421 { 422 swap(*__i, *__m); 423 ++__n_swaps; 424 } 425 // [__first, __i) < *__i and *__i <= [__i+1, __last) 426 // If we were given a perfect partition, see if insertion sort is quick... 427 if (__n_swaps == 0) 428 { 429 bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp); 430 if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp)) 431 { 432 if (__fs) 433 return; 434 __last = __i; 435 continue; 436 } 437 else 438 { 439 if (__fs) 440 { 441 __first = ++__i; 442 continue; 443 } 444 } 445 } 446 // sort smaller range with recursive call and larger with tail recursion elimination 447 if (__i - __first < __last - __i) 448 { 449 _VSTD::__sort<_Compare>(__first, __i, __comp); 450 // _VSTD::__sort<_Compare>(__i+1, __last, __comp); 451 __first = ++__i; 452 } 453 else 454 { 455 _VSTD::__sort<_Compare>(__i+1, __last, __comp); 456 // _VSTD::__sort<_Compare>(__first, __i, __comp); 457 __last = __i; 458 } 459 } 460 } 461 462 template <class _Compare, class _Tp> 463 inline _LIBCPP_INLINE_VISIBILITY 464 void 465 __sort(_Tp** __first, _Tp** __last, __less<_Tp*>&) 466 { 467 __less<uintptr_t> __comp; 468 _VSTD::__sort<__less<uintptr_t>&, uintptr_t*>((uintptr_t*)__first, (uintptr_t*)__last, __comp); 469 } 470 471 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&)) 472 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&)) 473 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&)) 474 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&)) 475 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&)) 476 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&)) 477 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&)) 478 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&)) 479 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&)) 480 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&)) 481 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&)) 482 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&)) 483 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&)) 484 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&)) 485 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&)) 486 487 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&)) 488 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&)) 489 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&)) 490 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&)) 491 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&)) 492 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&)) 493 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&)) 494 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&)) 495 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&)) 496 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&)) 497 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&)) 498 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&)) 499 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&)) 500 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&)) 501 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&)) 502 503 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&)) 504 505 template <class _RandomAccessIterator, class _Compare> 506 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 507 void 508 sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) 509 { 510 typedef typename __comp_ref_type<_Compare>::type _Comp_ref; 511 if (__libcpp_is_constant_evaluated()) { 512 _VSTD::__partial_sort<_Comp_ref>(__first, __last, __last, _Comp_ref(__comp)); 513 } else { 514 _VSTD::__sort<_Comp_ref>(_VSTD::__unwrap_iter(__first), _VSTD::__unwrap_iter(__last), _Comp_ref(__comp)); 515 } 516 } 517 518 template <class _RandomAccessIterator> 519 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 520 void 521 sort(_RandomAccessIterator __first, _RandomAccessIterator __last) 522 { 523 _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); 524 } 525 526 _LIBCPP_END_NAMESPACE_STD 527 528 _LIBCPP_POP_MACROS 529 530 #endif // _LIBCPP___ALGORITHM_SORT_H 531