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1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
11 #define _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
12 
13 #include <__algorithm/copy.h>
14 #include <__algorithm/move.h>
15 #include <__config>
16 #include <__iterator/iterator_traits.h>
17 #include <__iterator/reverse_iterator.h>
18 #include <__memory/addressof.h>
19 #include <__memory/allocator_traits.h>
20 #include <__memory/construct_at.h>
21 #include <__memory/pointer_traits.h>
22 #include <__memory/voidify.h>
23 #include <__type_traits/extent.h>
24 #include <__type_traits/is_array.h>
25 #include <__type_traits/is_constant_evaluated.h>
26 #include <__type_traits/is_trivially_copy_assignable.h>
27 #include <__type_traits/is_trivially_copy_constructible.h>
28 #include <__type_traits/is_trivially_move_assignable.h>
29 #include <__type_traits/is_trivially_move_constructible.h>
30 #include <__type_traits/is_unbounded_array.h>
31 #include <__type_traits/negation.h>
32 #include <__type_traits/remove_const.h>
33 #include <__type_traits/remove_extent.h>
34 #include <__utility/exception_guard.h>
35 #include <__utility/move.h>
36 #include <__utility/pair.h>
37 #include <new>
38 
39 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
40 #  pragma GCC system_header
41 #endif
42 
43 _LIBCPP_BEGIN_NAMESPACE_STD
44 
45 // This is a simplified version of C++20 `unreachable_sentinel` that doesn't use concepts and thus can be used in any
46 // language mode.
47 struct __unreachable_sentinel {
48   template <class _Iter>
49   _LIBCPP_HIDE_FROM_ABI friend _LIBCPP_CONSTEXPR bool operator!=(const _Iter&, __unreachable_sentinel) _NOEXCEPT {
50     return true;
51   }
52 };
53 
54 // uninitialized_copy
55 
56 template <class _ValueType, class _InputIterator, class _Sentinel1, class _ForwardIterator, class _Sentinel2>
57 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
__uninitialized_copy(_InputIterator __ifirst,_Sentinel1 __ilast,_ForwardIterator __ofirst,_Sentinel2 __olast)58 __uninitialized_copy(_InputIterator __ifirst, _Sentinel1 __ilast,
59                      _ForwardIterator __ofirst, _Sentinel2 __olast) {
60   _ForwardIterator __idx = __ofirst;
61 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
62   try {
63 #endif
64     for (; __ifirst != __ilast && __idx != __olast; ++__ifirst, (void)++__idx)
65       ::new (_VSTD::__voidify(*__idx)) _ValueType(*__ifirst);
66 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
67   } catch (...) {
68     _VSTD::__destroy(__ofirst, __idx);
69     throw;
70   }
71 #endif
72 
73   return pair<_InputIterator, _ForwardIterator>(_VSTD::move(__ifirst), _VSTD::move(__idx));
74 }
75 
76 template <class _InputIterator, class _ForwardIterator>
77 _LIBCPP_HIDE_FROM_ABI
uninitialized_copy(_InputIterator __ifirst,_InputIterator __ilast,_ForwardIterator __ofirst)78 _ForwardIterator uninitialized_copy(_InputIterator __ifirst, _InputIterator __ilast,
79                                     _ForwardIterator __ofirst) {
80   typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
81   auto __result = _VSTD::__uninitialized_copy<_ValueType>(_VSTD::move(__ifirst), _VSTD::move(__ilast),
82                                                           _VSTD::move(__ofirst), __unreachable_sentinel());
83   return _VSTD::move(__result.second);
84 }
85 
86 // uninitialized_copy_n
87 
88 template <class _ValueType, class _InputIterator, class _Size, class _ForwardIterator, class _Sentinel>
89 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
__uninitialized_copy_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst,_Sentinel __olast)90 __uninitialized_copy_n(_InputIterator __ifirst, _Size __n,
91                        _ForwardIterator __ofirst, _Sentinel __olast) {
92   _ForwardIterator __idx = __ofirst;
93 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
94   try {
95 #endif
96     for (; __n > 0 && __idx != __olast; ++__ifirst, (void)++__idx, (void)--__n)
97       ::new (_VSTD::__voidify(*__idx)) _ValueType(*__ifirst);
98 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
99   } catch (...) {
100     _VSTD::__destroy(__ofirst, __idx);
101     throw;
102   }
103 #endif
104 
105   return pair<_InputIterator, _ForwardIterator>(_VSTD::move(__ifirst), _VSTD::move(__idx));
106 }
107 
108 template <class _InputIterator, class _Size, class _ForwardIterator>
uninitialized_copy_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst)109 inline _LIBCPP_HIDE_FROM_ABI _ForwardIterator uninitialized_copy_n(_InputIterator __ifirst, _Size __n,
110                                                                    _ForwardIterator __ofirst) {
111   typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
112   auto __result = _VSTD::__uninitialized_copy_n<_ValueType>(_VSTD::move(__ifirst), __n, _VSTD::move(__ofirst),
113                                                             __unreachable_sentinel());
114   return _VSTD::move(__result.second);
115 }
116 
117 // uninitialized_fill
118 
119 template <class _ValueType, class _ForwardIterator, class _Sentinel, class _Tp>
120 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_fill(_ForwardIterator __first,_Sentinel __last,const _Tp & __x)121 _ForwardIterator __uninitialized_fill(_ForwardIterator __first, _Sentinel __last, const _Tp& __x)
122 {
123     _ForwardIterator __idx = __first;
124 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
125     try
126     {
127 #endif
128         for (; __idx != __last; ++__idx)
129             ::new (_VSTD::__voidify(*__idx)) _ValueType(__x);
130 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
131     }
132     catch (...)
133     {
134         _VSTD::__destroy(__first, __idx);
135         throw;
136     }
137 #endif
138 
139     return __idx;
140 }
141 
142 template <class _ForwardIterator, class _Tp>
143 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_fill(_ForwardIterator __first,_ForwardIterator __last,const _Tp & __x)144 void uninitialized_fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __x)
145 {
146     typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
147     (void)_VSTD::__uninitialized_fill<_ValueType>(__first, __last, __x);
148 }
149 
150 // uninitialized_fill_n
151 
152 template <class _ValueType, class _ForwardIterator, class _Size, class _Tp>
153 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_fill_n(_ForwardIterator __first,_Size __n,const _Tp & __x)154 _ForwardIterator __uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
155 {
156     _ForwardIterator __idx = __first;
157 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
158     try
159     {
160 #endif
161         for (; __n > 0; ++__idx, (void) --__n)
162             ::new (_VSTD::__voidify(*__idx)) _ValueType(__x);
163 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
164     }
165     catch (...)
166     {
167         _VSTD::__destroy(__first, __idx);
168         throw;
169     }
170 #endif
171 
172     return __idx;
173 }
174 
175 template <class _ForwardIterator, class _Size, class _Tp>
176 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_fill_n(_ForwardIterator __first,_Size __n,const _Tp & __x)177 _ForwardIterator uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
178 {
179     typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
180     return _VSTD::__uninitialized_fill_n<_ValueType>(__first, __n, __x);
181 }
182 
183 #if _LIBCPP_STD_VER >= 17
184 
185 // uninitialized_default_construct
186 
187 template <class _ValueType, class _ForwardIterator, class _Sentinel>
188 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_default_construct(_ForwardIterator __first,_Sentinel __last)189 _ForwardIterator __uninitialized_default_construct(_ForwardIterator __first, _Sentinel __last) {
190     auto __idx = __first;
191 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
192     try {
193 #endif
194     for (; __idx != __last; ++__idx)
195         ::new (_VSTD::__voidify(*__idx)) _ValueType;
196 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
197     } catch (...) {
198         _VSTD::__destroy(__first, __idx);
199         throw;
200     }
201 #endif
202 
203     return __idx;
204 }
205 
206 template <class _ForwardIterator>
207 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_default_construct(_ForwardIterator __first,_ForwardIterator __last)208 void uninitialized_default_construct(_ForwardIterator __first, _ForwardIterator __last) {
209     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
210     (void)_VSTD::__uninitialized_default_construct<_ValueType>(
211         _VSTD::move(__first), _VSTD::move(__last));
212 }
213 
214 // uninitialized_default_construct_n
215 
216 template <class _ValueType, class _ForwardIterator, class _Size>
217 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_default_construct_n(_ForwardIterator __first,_Size __n)218 _ForwardIterator __uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
219     auto __idx = __first;
220 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
221     try {
222 #endif
223     for (; __n > 0; ++__idx, (void) --__n)
224         ::new (_VSTD::__voidify(*__idx)) _ValueType;
225 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
226     } catch (...) {
227         _VSTD::__destroy(__first, __idx);
228         throw;
229     }
230 #endif
231 
232     return __idx;
233 }
234 
235 template <class _ForwardIterator, class _Size>
236 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_default_construct_n(_ForwardIterator __first,_Size __n)237 _ForwardIterator uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
238     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
239     return _VSTD::__uninitialized_default_construct_n<_ValueType>(_VSTD::move(__first), __n);
240 }
241 
242 // uninitialized_value_construct
243 
244 template <class _ValueType, class _ForwardIterator, class _Sentinel>
245 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_value_construct(_ForwardIterator __first,_Sentinel __last)246 _ForwardIterator __uninitialized_value_construct(_ForwardIterator __first, _Sentinel __last) {
247     auto __idx = __first;
248 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
249     try {
250 #endif
251     for (; __idx != __last; ++__idx)
252         ::new (_VSTD::__voidify(*__idx)) _ValueType();
253 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
254     } catch (...) {
255         _VSTD::__destroy(__first, __idx);
256         throw;
257     }
258 #endif
259 
260     return __idx;
261 }
262 
263 template <class _ForwardIterator>
264 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_value_construct(_ForwardIterator __first,_ForwardIterator __last)265 void uninitialized_value_construct(_ForwardIterator __first, _ForwardIterator __last) {
266     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
267     (void)_VSTD::__uninitialized_value_construct<_ValueType>(
268         _VSTD::move(__first), _VSTD::move(__last));
269 }
270 
271 // uninitialized_value_construct_n
272 
273 template <class _ValueType, class _ForwardIterator, class _Size>
274 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_value_construct_n(_ForwardIterator __first,_Size __n)275 _ForwardIterator __uninitialized_value_construct_n(_ForwardIterator __first, _Size __n) {
276     auto __idx = __first;
277 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
278     try {
279 #endif
280     for (; __n > 0; ++__idx, (void) --__n)
281         ::new (_VSTD::__voidify(*__idx)) _ValueType();
282 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
283     } catch (...) {
284         _VSTD::__destroy(__first, __idx);
285         throw;
286     }
287 #endif
288 
289     return __idx;
290 }
291 
292 template <class _ForwardIterator, class _Size>
293 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_value_construct_n(_ForwardIterator __first,_Size __n)294 _ForwardIterator uninitialized_value_construct_n(_ForwardIterator __first, _Size __n) {
295     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
296     return std::__uninitialized_value_construct_n<_ValueType>(_VSTD::move(__first), __n);
297 }
298 
299 // uninitialized_move
300 
301 template <class _ValueType, class _InputIterator, class _Sentinel1, class _ForwardIterator, class _Sentinel2,
302           class _IterMove>
303 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
__uninitialized_move(_InputIterator __ifirst,_Sentinel1 __ilast,_ForwardIterator __ofirst,_Sentinel2 __olast,_IterMove __iter_move)304 __uninitialized_move(_InputIterator __ifirst, _Sentinel1 __ilast,
305                      _ForwardIterator __ofirst, _Sentinel2 __olast, _IterMove __iter_move) {
306   auto __idx = __ofirst;
307 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
308   try {
309 #endif
310     for (; __ifirst != __ilast && __idx != __olast; ++__idx, (void)++__ifirst) {
311       ::new (_VSTD::__voidify(*__idx)) _ValueType(__iter_move(__ifirst));
312     }
313 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
314   } catch (...) {
315     _VSTD::__destroy(__ofirst, __idx);
316     throw;
317   }
318 #endif
319 
320   return {_VSTD::move(__ifirst), _VSTD::move(__idx)};
321 }
322 
323 template <class _InputIterator, class _ForwardIterator>
uninitialized_move(_InputIterator __ifirst,_InputIterator __ilast,_ForwardIterator __ofirst)324 inline _LIBCPP_HIDE_FROM_ABI _ForwardIterator uninitialized_move(_InputIterator __ifirst, _InputIterator __ilast,
325                                                                  _ForwardIterator __ofirst) {
326   using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
327   auto __iter_move = [](auto&& __iter) -> decltype(auto) { return _VSTD::move(*__iter); };
328 
329   auto __result = _VSTD::__uninitialized_move<_ValueType>(_VSTD::move(__ifirst), _VSTD::move(__ilast),
330                                                           _VSTD::move(__ofirst), __unreachable_sentinel(), __iter_move);
331   return _VSTD::move(__result.second);
332 }
333 
334 // uninitialized_move_n
335 
336 template <class _ValueType, class _InputIterator, class _Size, class _ForwardIterator, class _Sentinel, class _IterMove>
337 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
__uninitialized_move_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst,_Sentinel __olast,_IterMove __iter_move)338 __uninitialized_move_n(_InputIterator __ifirst, _Size __n,
339                        _ForwardIterator __ofirst, _Sentinel __olast, _IterMove __iter_move) {
340   auto __idx = __ofirst;
341 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
342   try {
343 #endif
344     for (; __n > 0 && __idx != __olast; ++__idx, (void)++__ifirst, --__n)
345       ::new (_VSTD::__voidify(*__idx)) _ValueType(__iter_move(__ifirst));
346 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
347   } catch (...) {
348     _VSTD::__destroy(__ofirst, __idx);
349     throw;
350   }
351 #endif
352 
353   return {_VSTD::move(__ifirst), _VSTD::move(__idx)};
354 }
355 
356 template <class _InputIterator, class _Size, class _ForwardIterator>
357 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
uninitialized_move_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst)358 uninitialized_move_n(_InputIterator __ifirst, _Size __n, _ForwardIterator __ofirst) {
359   using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
360   auto __iter_move = [](auto&& __iter) -> decltype(auto) { return _VSTD::move(*__iter); };
361 
362   return _VSTD::__uninitialized_move_n<_ValueType>(_VSTD::move(__ifirst), __n, _VSTD::move(__ofirst),
363                                                    __unreachable_sentinel(), __iter_move);
364 }
365 
366 // TODO: Rewrite this to iterate left to right and use reverse_iterators when calling
367 // Destroys every element in the range [first, last) FROM RIGHT TO LEFT using allocator
368 // destruction. If elements are themselves C-style arrays, they are recursively destroyed
369 // in the same manner.
370 //
371 // This function assumes that destructors do not throw, and that the allocator is bound to
372 // the correct type.
373 template<class _Alloc, class _BidirIter, class = __enable_if_t<
374     __is_cpp17_bidirectional_iterator<_BidirIter>::value
375 >>
376 _LIBCPP_HIDE_FROM_ABI
__allocator_destroy_multidimensional(_Alloc & __alloc,_BidirIter __first,_BidirIter __last)377 constexpr void __allocator_destroy_multidimensional(_Alloc& __alloc, _BidirIter __first, _BidirIter __last) noexcept {
378     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
379     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _ValueType>,
380         "The allocator should already be rebound to the correct type");
381 
382     if (__first == __last)
383         return;
384 
385     if constexpr (is_array_v<_ValueType>) {
386         static_assert(!__libcpp_is_unbounded_array<_ValueType>::value,
387             "arrays of unbounded arrays don't exist, but if they did we would mess up here");
388 
389         using _Element = remove_extent_t<_ValueType>;
390         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
391         do {
392             --__last;
393             decltype(auto) __array = *__last;
394             std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + extent_v<_ValueType>);
395         } while (__last != __first);
396     } else {
397         do {
398             --__last;
399             allocator_traits<_Alloc>::destroy(__alloc, std::addressof(*__last));
400         } while (__last != __first);
401     }
402 }
403 
404 // Constructs the object at the given location using the allocator's construct method.
405 //
406 // If the object being constructed is an array, each element of the array is allocator-constructed,
407 // recursively. If an exception is thrown during the construction of an array, the initialized
408 // elements are destroyed in reverse order of initialization using allocator destruction.
409 //
410 // This function assumes that the allocator is bound to the correct type.
411 template<class _Alloc, class _Tp>
412 _LIBCPP_HIDE_FROM_ABI
__allocator_construct_at_multidimensional(_Alloc & __alloc,_Tp * __loc)413 constexpr void __allocator_construct_at_multidimensional(_Alloc& __alloc, _Tp* __loc) {
414     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _Tp>,
415         "The allocator should already be rebound to the correct type");
416 
417     if constexpr (is_array_v<_Tp>) {
418         using _Element = remove_extent_t<_Tp>;
419         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
420         size_t __i = 0;
421         _Tp& __array = *__loc;
422 
423         // If an exception is thrown, destroy what we have constructed so far in reverse order.
424         auto __guard = std::__make_exception_guard([&]() {
425           std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + __i);
426         });
427 
428         for (; __i != extent_v<_Tp>; ++__i) {
429             std::__allocator_construct_at_multidimensional(__elem_alloc, std::addressof(__array[__i]));
430         }
431         __guard.__complete();
432     } else {
433         allocator_traits<_Alloc>::construct(__alloc, __loc);
434     }
435 }
436 
437 // Constructs the object at the given location using the allocator's construct method, passing along
438 // the provided argument.
439 //
440 // If the object being constructed is an array, the argument is also assumed to be an array. Each
441 // each element of the array being constructed is allocator-constructed from the corresponding
442 // element of the argument array. If an exception is thrown during the construction of an array,
443 // the initialized elements are destroyed in reverse order of initialization using allocator
444 // destruction.
445 //
446 // This function assumes that the allocator is bound to the correct type.
447 template<class _Alloc, class _Tp, class _Arg>
448 _LIBCPP_HIDE_FROM_ABI
__allocator_construct_at_multidimensional(_Alloc & __alloc,_Tp * __loc,_Arg const & __arg)449 constexpr void __allocator_construct_at_multidimensional(_Alloc& __alloc, _Tp* __loc, _Arg const& __arg) {
450     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _Tp>,
451         "The allocator should already be rebound to the correct type");
452 
453     if constexpr (is_array_v<_Tp>) {
454         static_assert(is_array_v<_Arg>,
455             "Provided non-array initialization argument to __allocator_construct_at_multidimensional when "
456             "trying to construct an array.");
457 
458         using _Element = remove_extent_t<_Tp>;
459         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
460         size_t __i = 0;
461         _Tp& __array = *__loc;
462 
463         // If an exception is thrown, destroy what we have constructed so far in reverse order.
464         auto __guard = std::__make_exception_guard([&]() {
465           std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + __i);
466         });
467         for (; __i != extent_v<_Tp>; ++__i) {
468             std::__allocator_construct_at_multidimensional(__elem_alloc, std::addressof(__array[__i]), __arg[__i]);
469         }
470         __guard.__complete();
471     } else {
472         allocator_traits<_Alloc>::construct(__alloc, __loc, __arg);
473     }
474 }
475 
476 // Given a range starting at it and containing n elements, initializes each element in the
477 // range from left to right using the construct method of the allocator (rebound to the
478 // correct type).
479 //
480 // If an exception is thrown, the initialized elements are destroyed in reverse order of
481 // initialization using allocator_traits destruction. If the elements in the range are C-style
482 // arrays, they are initialized element-wise using allocator construction, and recursively so.
483 template<class _Alloc, class _BidirIter, class _Tp, class _Size = typename iterator_traits<_BidirIter>::difference_type>
484 _LIBCPP_HIDE_FROM_ABI constexpr void
__uninitialized_allocator_fill_n_multidimensional(_Alloc & __alloc,_BidirIter __it,_Size __n,_Tp const & __value)485 __uninitialized_allocator_fill_n_multidimensional(_Alloc& __alloc, _BidirIter __it, _Size __n, _Tp const& __value) {
486     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
487     __allocator_traits_rebind_t<_Alloc, _ValueType> __value_alloc(__alloc);
488     _BidirIter __begin = __it;
489 
490     // If an exception is thrown, destroy what we have constructed so far in reverse order.
491     auto __guard = std::__make_exception_guard([&]() { std::__allocator_destroy_multidimensional(__value_alloc, __begin, __it); });
492     for (; __n != 0; --__n, ++__it) {
493         std::__allocator_construct_at_multidimensional(__value_alloc, std::addressof(*__it), __value);
494     }
495     __guard.__complete();
496 }
497 
498 // Same as __uninitialized_allocator_fill_n_multidimensional, but doesn't pass any initialization argument
499 // to the allocator's construct method, which results in value initialization.
500 template <class _Alloc, class _BidirIter, class _Size = typename iterator_traits<_BidirIter>::difference_type>
501 _LIBCPP_HIDE_FROM_ABI constexpr void
__uninitialized_allocator_value_construct_n_multidimensional(_Alloc & __alloc,_BidirIter __it,_Size __n)502 __uninitialized_allocator_value_construct_n_multidimensional(_Alloc& __alloc, _BidirIter __it, _Size __n) {
503     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
504     __allocator_traits_rebind_t<_Alloc, _ValueType> __value_alloc(__alloc);
505     _BidirIter __begin = __it;
506 
507     // If an exception is thrown, destroy what we have constructed so far in reverse order.
508     auto __guard = std::__make_exception_guard([&]() { std::__allocator_destroy_multidimensional(__value_alloc, __begin, __it); });
509     for (; __n != 0; --__n, ++__it) {
510         std::__allocator_construct_at_multidimensional(__value_alloc, std::addressof(*__it));
511     }
512     __guard.__complete();
513 }
514 
515 #endif // _LIBCPP_STD_VER >= 17
516 
517 // Destroy all elements in [__first, __last) from left to right using allocator destruction.
518 template <class _Alloc, class _Iter, class _Sent>
519 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
__allocator_destroy(_Alloc & __alloc,_Iter __first,_Sent __last)520 __allocator_destroy(_Alloc& __alloc, _Iter __first, _Sent __last) {
521   for (; __first != __last; ++__first)
522      allocator_traits<_Alloc>::destroy(__alloc, std::__to_address(__first));
523 }
524 
525 template <class _Alloc, class _Iter>
526 class _AllocatorDestroyRangeReverse {
527 public:
528   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
_AllocatorDestroyRangeReverse(_Alloc & __alloc,_Iter & __first,_Iter & __last)529   _AllocatorDestroyRangeReverse(_Alloc& __alloc, _Iter& __first, _Iter& __last)
530       : __alloc_(__alloc), __first_(__first), __last_(__last) {}
531 
operator()532   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void operator()() const {
533     std::__allocator_destroy(__alloc_, std::reverse_iterator<_Iter>(__last_), std::reverse_iterator<_Iter>(__first_));
534   }
535 
536 private:
537   _Alloc& __alloc_;
538   _Iter& __first_;
539   _Iter& __last_;
540 };
541 
542 // Copy-construct [__first1, __last1) in [__first2, __first2 + N), where N is distance(__first1, __last1).
543 //
544 // The caller has to ensure that __first2 can hold at least N uninitialized elements. If an exception is thrown the
545 // already copied elements are destroyed in reverse order of their construction.
546 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
547 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2
__uninitialized_allocator_copy(_Alloc & __alloc,_Iter1 __first1,_Sent1 __last1,_Iter2 __first2)548 __uninitialized_allocator_copy(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
549   auto __destruct_first = __first2;
550   auto __guard =
551       std::__make_exception_guard(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
552   while (__first1 != __last1) {
553     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), *__first1);
554     ++__first1;
555     ++__first2;
556   }
557   __guard.__complete();
558   return __first2;
559 }
560 
561 template <class _Alloc, class _Type>
562 struct __allocator_has_trivial_copy_construct : _Not<__has_construct<_Alloc, _Type*, const _Type&> > {};
563 
564 template <class _Type>
565 struct __allocator_has_trivial_copy_construct<allocator<_Type>, _Type> : true_type {};
566 
567 template <class _Alloc,
568           class _Type,
569           class _RawType = __remove_const_t<_Type>,
570           __enable_if_t<
571               // using _RawType because of the allocator<T const> extension
572               is_trivially_copy_constructible<_RawType>::value && is_trivially_copy_assignable<_RawType>::value &&
573               __allocator_has_trivial_copy_construct<_Alloc, _RawType>::value>* = nullptr>
574 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Type*
575 __uninitialized_allocator_copy(_Alloc&, const _Type* __first1, const _Type* __last1, _Type* __first2) {
576   // TODO: Remove the const_cast once we drop support for std::allocator<T const>
577   if (__libcpp_is_constant_evaluated()) {
578     while (__first1 != __last1) {
579       std::__construct_at(std::__to_address(__first2), *__first1);
580       ++__first1;
581       ++__first2;
582     }
583     return __first2;
584   } else {
585     return std::copy(__first1, __last1, const_cast<_RawType*>(__first2));
586   }
587 }
588 
589 // Move-construct the elements [__first1, __last1) into [__first2, __first2 + N)
590 // if the move constructor is noexcept, where N is distance(__first1, __last1).
591 //
592 // Otherwise try to copy all elements. If an exception is thrown the already copied
593 // elements are destroyed in reverse order of their construction.
594 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
595 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2 __uninitialized_allocator_move_if_noexcept(
596     _Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
597   static_assert(__is_cpp17_move_insertable<_Alloc>::value,
598                 "The specified type does not meet the requirements of Cpp17MoveInsertable");
599   auto __destruct_first = __first2;
600   auto __guard =
601       std::__make_exception_guard(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
602   while (__first1 != __last1) {
603 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
604     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), std::move_if_noexcept(*__first1));
605 #else
606     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), std::move(*__first1));
607 #endif
608     ++__first1;
609     ++__first2;
610   }
611   __guard.__complete();
612   return __first2;
613 }
614 
615 template <class _Alloc, class _Type>
616 struct __allocator_has_trivial_move_construct : _Not<__has_construct<_Alloc, _Type*, _Type&&> > {};
617 
618 template <class _Type>
619 struct __allocator_has_trivial_move_construct<allocator<_Type>, _Type> : true_type {};
620 
621 #ifndef _LIBCPP_COMPILER_GCC
622 template <
623     class _Alloc,
624     class _Iter1,
625     class _Iter2,
626     class _Type = typename iterator_traits<_Iter1>::value_type,
627     class = __enable_if_t<is_trivially_move_constructible<_Type>::value && is_trivially_move_assignable<_Type>::value &&
628                           __allocator_has_trivial_move_construct<_Alloc, _Type>::value> >
629 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2
630 __uninitialized_allocator_move_if_noexcept(_Alloc&, _Iter1 __first1, _Iter1 __last1, _Iter2 __first2) {
631   if (__libcpp_is_constant_evaluated()) {
632     while (__first1 != __last1) {
633       std::__construct_at(std::__to_address(__first2), std::move(*__first1));
634       ++__first1;
635       ++__first2;
636     }
637     return __first2;
638   } else {
639     return std::move(__first1, __last1, __first2);
640   }
641 }
642 #endif // _LIBCPP_COMPILER_GCC
643 
644 _LIBCPP_END_NAMESPACE_STD
645 
646 #endif // _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
647