libstdc++
memory
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1 // <memory> -*- C++ -*-
2 
3 // Copyright (C) 2001-2019 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  * Copyright (c) 1997-1999
27  * Silicon Graphics Computer Systems, Inc.
28  *
29  * Permission to use, copy, modify, distribute and sell this software
30  * and its documentation for any purpose is hereby granted without fee,
31  * provided that the above copyright notice appear in all copies and
32  * that both that copyright notice and this permission notice appear
33  * in supporting documentation. Silicon Graphics makes no
34  * representations about the suitability of this software for any
35  * purpose. It is provided "as is" without express or implied warranty.
36  *
37  */
38 
39 /** @file include/memory
40  * This is a Standard C++ Library header.
41  */
42 
43 #ifndef _GLIBCXX_MEMORY
44 #define _GLIBCXX_MEMORY 1
45 
46 #pragma GCC system_header
47 
48 /**
49  * @defgroup memory Memory
50  * @ingroup utilities
51  *
52  * Components for memory allocation, deallocation, and management.
53  */
54 
55 /**
56  * @defgroup pointer_abstractions Pointer Abstractions
57  * @ingroup memory
58  *
59  * Smart pointers, etc.
60  */
61 
62 #include <bits/stl_algobase.h>
63 #include <bits/allocator.h>
64 #include <bits/stl_construct.h>
65 #include <bits/stl_uninitialized.h>
66 #include <bits/stl_tempbuf.h>
67 #include <bits/stl_raw_storage_iter.h>
68 
69 #if __cplusplus >= 201103L
70 # include <exception> // std::exception
71 # include <typeinfo> // std::type_info in get_deleter
72 # include <iosfwd> // std::basic_ostream
73 # include <ext/atomicity.h>
74 # include <ext/concurrence.h>
75 # include <bits/functexcept.h>
76 # include <bits/stl_function.h> // std::less
77 # include <bits/uses_allocator.h>
78 # include <type_traits>
79 # include <debug/debug.h>
80 # include <bits/unique_ptr.h>
81 # include <bits/shared_ptr.h>
82 # include <bits/shared_ptr_atomic.h>
83 # if _GLIBCXX_USE_DEPRECATED
84 # include <backward/auto_ptr.h>
85 # endif
86 #else
87 # include <backward/auto_ptr.h>
88 #endif
89 
90 #if __cplusplus >= 201103L
91 #include <cstdint>
92 #if __cplusplus > 201703L
93 # include <bit> // for ispow2
94 # include <new> // for placement operator new
95 # include <tuple> // for tuple, make_tuple, make_from_tuple
96 #endif
97 namespace std _GLIBCXX_VISIBILITY(default)
98 {
99 _GLIBCXX_BEGIN_NAMESPACE_VERSION
100 
101 /**
102  * @brief Fit aligned storage in buffer.
103  *
104  * [ptr.align]
105  *
106  * This function tries to fit @a __size bytes of storage with alignment
107  * @a __align into the buffer @a __ptr of size @a __space bytes. If such
108  * a buffer fits then @a __ptr is changed to point to the first byte of the
109  * aligned storage and @a __space is reduced by the bytes used for alignment.
110  *
111  * @param __align A fundamental or extended alignment value.
112  * @param __size Size of the aligned storage required.
113  * @param __ptr Pointer to a buffer of @a __space bytes.
114  * @param __space Size of the buffer pointed to by @a __ptr.
115  * @return the updated pointer if the aligned storage fits, otherwise nullptr.
116  */
117 inline void*
118 align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
119 {
120 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
121  const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
122 #else
123  // Cannot use std::uintptr_t so assume that std::size_t can be used instead.
124  static_assert(sizeof(size_t) >= sizeof(void*),
125  "std::size_t must be a suitable substitute for std::uintptr_t");
126  const auto __intptr = reinterpret_cast<unsigned long long>(__ptr);
127 #endif
128  const auto __aligned = (__intptr - 1u + __align) & -__align;
129  const auto __diff = __aligned - __intptr;
130  if ((__size + __diff) > __space)
131  return nullptr;
132  else
133  {
134  __space -= __diff;
135  return __ptr = reinterpret_cast<void*>(__aligned);
136  }
137 }
138 
139 // 20.7.4 [util.dynamic.safety], pointer safety
140 
141 enum class pointer_safety { relaxed, preferred, strict };
142 
143 inline void
144 declare_reachable(void*) { }
145 
146 template <typename _Tp>
147  inline _Tp*
148  undeclare_reachable(_Tp* __p) { return __p; }
149 
150 inline void
151 declare_no_pointers(char*, size_t) { }
152 
153 inline void
154 undeclare_no_pointers(char*, size_t) { }
155 
156 inline pointer_safety
157 get_pointer_safety() noexcept { return pointer_safety::relaxed; }
158 
159 #if __cplusplus > 201703L
160  /// Inform the compiler that a pointer is aligned.
161  template<size_t _Align, class _Tp>
162  [[nodiscard,__gnu__::__always_inline__]]
163  constexpr _Tp* assume_aligned(_Tp* __ptr)
164  {
165  static_assert(std::ispow2(_Align));
166  _GLIBCXX_DEBUG_ASSERT((std::uintptr_t)__ptr % _Align == 0);
167  return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Align));
168  }
169 #endif // C++2a
170 
171 #if __cplusplus > 201703L
172  template<typename _Tp>
173  struct __is_pair : false_type { };
174  template<typename _Tp, typename _Up>
175  struct __is_pair<pair<_Tp, _Up>> : true_type { };
176  template<typename _Tp, typename _Up>
177  struct __is_pair<const pair<_Tp, _Up>> : true_type { };
178 
179  template<typename _Tp, typename __ = _Require<__not_<__is_pair<_Tp>>>,
180  typename _Alloc, typename... _Args>
181  constexpr auto
182  __uses_alloc_args(const _Alloc& __a, _Args&&... __args) noexcept
183  {
184  if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
185  {
186  if constexpr (is_constructible_v<_Tp, allocator_arg_t,
187  const _Alloc&, _Args...>)
188  {
189  return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
190  allocator_arg, __a, std::forward<_Args>(__args)...);
191  }
192  else
193  {
194  static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
195  "construction with an allocator must be possible"
196  " if uses_allocator is true");
197 
198  return tuple<_Args&&..., const _Alloc&>(
199  std::forward<_Args>(__args)..., __a);
200  }
201  }
202  else
203  {
204  static_assert(is_constructible_v<_Tp, _Args...>);
205 
206  return tuple<_Args&&...>(std::forward<_Args>(__args)...);
207  }
208  }
209 
210 #if __cpp_concepts
211  template<typename _Tp>
212  concept _Std_pair = __is_pair<_Tp>::value;
213 #endif
214 
215 // This is a temporary workaround until -fconcepts is implied by -std=gnu++2a
216 #if __cpp_concepts
217 # define _GLIBCXX_STD_PAIR_CONSTRAINT(T) _Std_pair T
218 # define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) _Std_pair T
219 #else
220 # define _GLIBCXX_STD_PAIR_CONSTRAINT(T) \
221  typename T, typename __ = _Require<__is_pair<T>>
222 # define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) typename T, typename
223 #endif
224 
225  template<typename _Tp,
226 #if ! __cpp_concepts
227  typename __ = _Require<__not_<__is_pair<_Tp>>>,
228 #endif
229  typename _Alloc, typename... _Args>
230  constexpr auto
231  uses_allocator_construction_args(const _Alloc& __a,
232  _Args&&... __args) noexcept
233 #if __cpp_concepts
234  requires (! _Std_pair<_Tp>)
235 #endif
236  {
237  return std::__uses_alloc_args<_Tp>(__a, std::forward<_Args>(__args)...);
238  }
239 
240  template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
241  typename _Tuple1, typename _Tuple2>
242  constexpr auto
243  uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
244  _Tuple1&& __x, _Tuple2&& __y) noexcept;
245 
246  template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc>
247  constexpr auto
248  uses_allocator_construction_args(const _Alloc&) noexcept;
249 
250  template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
251  typename _Up, typename _Vp>
252  constexpr auto
253  uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
254 
255  template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
256  typename _Up, typename _Vp>
257  constexpr auto
258  uses_allocator_construction_args(const _Alloc&,
259  const pair<_Up, _Vp>&) noexcept;
260 
261  template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
262  typename _Up, typename _Vp>
263  constexpr auto
264  uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
265 
266  template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
267  typename _Tuple1, typename _Tuple2>
268  constexpr auto
269  uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
270  _Tuple1&& __x, _Tuple2&& __y) noexcept
271  {
272  using _Tp1 = typename _Tp::first_type;
273  using _Tp2 = typename _Tp::second_type;
274 
275  return std::make_tuple(piecewise_construct,
276  std::apply([&__a](auto&&... __args1) {
277  return std::uses_allocator_construction_args<_Tp1>(
278  __a, std::forward<decltype(__args1)>(__args1)...);
279  }, std::forward<_Tuple1>(__x)),
280  std::apply([&__a](auto&&... __args2) {
281  return std::uses_allocator_construction_args<_Tp2>(
282  __a, std::forward<decltype(__args2)>(__args2)...);
283  }, std::forward<_Tuple2>(__y)));
284  }
285 
286  template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc>
287  constexpr auto
288  uses_allocator_construction_args(const _Alloc& __a) noexcept
289  {
290  using _Tp1 = typename _Tp::first_type;
291  using _Tp2 = typename _Tp::second_type;
292 
293  return std::make_tuple(piecewise_construct,
294  std::uses_allocator_construction_args<_Tp1>(__a),
295  std::uses_allocator_construction_args<_Tp2>(__a));
296  }
297 
298  template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
299  typename _Up, typename _Vp>
300  constexpr auto
301  uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
302  noexcept
303  {
304  using _Tp1 = typename _Tp::first_type;
305  using _Tp2 = typename _Tp::second_type;
306 
307  return std::make_tuple(piecewise_construct,
308  std::uses_allocator_construction_args<_Tp1>(__a,
309  std::forward<_Up>(__u)),
310  std::uses_allocator_construction_args<_Tp2>(__a,
311  std::forward<_Vp>(__v)));
312  }
313 
314  template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
315  typename _Up, typename _Vp>
316  constexpr auto
317  uses_allocator_construction_args(const _Alloc& __a,
318  const pair<_Up, _Vp>& __pr) noexcept
319  {
320  using _Tp1 = typename _Tp::first_type;
321  using _Tp2 = typename _Tp::second_type;
322 
323  return std::make_tuple(piecewise_construct,
324  std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
325  std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
326  }
327 
328  template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
329  typename _Up, typename _Vp>
330  constexpr auto
331  uses_allocator_construction_args(const _Alloc& __a,
332  pair<_Up, _Vp>&& __pr) noexcept
333  {
334  using _Tp1 = typename _Tp::first_type;
335  using _Tp2 = typename _Tp::second_type;
336 
337  return std::make_tuple(piecewise_construct,
338  std::uses_allocator_construction_args<_Tp1>(__a,
339  std::move(__pr).first),
340  std::uses_allocator_construction_args<_Tp2>(__a,
341  std::move(__pr).second));
342  }
343 
344  template<typename _Tp, typename _Alloc, typename... _Args>
345  inline _Tp
346  make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
347  {
348  return std::make_from_tuple<_Tp>(
349  std::uses_allocator_construction_args<_Tp>(__a,
350  std::forward<_Args>(__args)...));
351  }
352 
353  template<typename _Tp, typename _Alloc, typename... _Args>
354  inline _Tp*
355  uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
356  _Args&&... __args)
357  {
358  void* __vp = const_cast<void*>(static_cast<const volatile void*>(__p));
359  return ::new(__vp) _Tp(std::make_obj_using_allocator<_Tp>(__a,
360  std::forward<_Args>(__args)...));
361  }
362 
363 #endif // C++2a
364 
365 _GLIBCXX_END_NAMESPACE_VERSION
366 } // namespace
367 #endif // C++11
368 
369 #if __cplusplus > 201402L
370 // Parallel STL algorithms
371 # if __PSTL_EXECUTION_POLICIES_DEFINED
372 // If <execution> has already been included, pull in implementations
373 # include <pstl/glue_memory_impl.h>
374 # else
375 // Otherwise just pull in forward declarations
376 # include <pstl/glue_memory_defs.h>
377 # endif
378 
379 // Feature test macro for parallel algorithms
380 # define __cpp_lib_parallel_algorithm 201603L
381 #endif // C++17
382 
383 #endif /* _GLIBCXX_MEMORY */