1 // <memory> -*- C++ -*-
3 // Copyright (C) 2001-2020 Free Software Foundation, Inc.
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)
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.
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.
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/>.
26 * Copyright (c) 1997-1999
27 * Silicon Graphics Computer Systems, Inc.
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.
39 /** @file include/memory
40 * This is a Standard C++ Library header.
44 #ifndef _GLIBCXX_MEMORY
45 #define _GLIBCXX_MEMORY 1
47 #pragma GCC system_header
50 * @defgroup memory Memory
53 * Components for memory allocation, deallocation, and management.
57 * @defgroup pointer_abstractions Pointer Abstractions
60 * Smart pointers, etc.
63 #include <bits/stl_algobase.h>
64 #include <bits/allocator.h>
65 #include <bits/stl_construct.h>
66 #include <bits/stl_uninitialized.h>
67 #include <bits/stl_tempbuf.h>
68 #include <bits/stl_raw_storage_iter.h>
69 #include <bits/ranges_uninitialized.h>
71 #if __cplusplus >= 201103L
72 # include <exception> // std::exception
73 # include <typeinfo> // std::type_info in get_deleter
74 # include <iosfwd> // std::basic_ostream
75 # include <ext/atomicity.h>
76 # include <ext/concurrence.h>
77 # include <bits/functexcept.h>
78 # include <bits/stl_function.h> // std::less
79 # include <bits/uses_allocator.h>
80 # include <bits/alloc_traits.h>
81 # include <type_traits>
82 # include <debug/debug.h>
83 # include <bits/unique_ptr.h>
84 # include <bits/shared_ptr.h>
85 # include <bits/shared_ptr_atomic.h>
86 # if _GLIBCXX_USE_DEPRECATED
87 # include <backward/auto_ptr.h>
90 # include <backward/auto_ptr.h>
93 #if __cplusplus >= 201103L
95 #if __cplusplus > 201703L
96 # include <bit> // for has_single_bit
97 # include <new> // for placement operator new
98 # include <tuple> // for tuple, make_tuple, make_from_tuple
100 namespace std _GLIBCXX_VISIBILITY(default)
102 _GLIBCXX_BEGIN_NAMESPACE_VERSION
105 * @brief Fit aligned storage in buffer.
108 * This function tries to fit @a __size bytes of storage with alignment
109 * @a __align into the buffer @a __ptr of size @a __space bytes. If such
110 * a buffer fits then @a __ptr is changed to point to the first byte of the
111 * aligned storage and @a __space is reduced by the bytes used for alignment.
113 * C++11 20.6.5 [ptr.align]
115 * @param __align A fundamental or extended alignment value.
116 * @param __size Size of the aligned storage required.
117 * @param __ptr Pointer to a buffer of @a __space bytes.
118 * @param __space Size of the buffer pointed to by @a __ptr.
119 * @return the updated pointer if the aligned storage fits, otherwise nullptr.
123 align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
125 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
126 const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
128 // Cannot use std::uintptr_t so assume that std::size_t can be used instead.
129 static_assert(sizeof(size_t) >= sizeof(void*),
130 "std::size_t must be a suitable substitute for std::uintptr_t");
131 const auto __intptr = reinterpret_cast<unsigned long long>(__ptr);
133 const auto __aligned = (__intptr - 1u + __align) & -__align;
134 const auto __diff = __aligned - __intptr;
135 if ((__size + __diff) > __space)
140 return __ptr = reinterpret_cast<void*>(__aligned);
144 /** @defgroup ptr_safety Pointer Safety and Garbage Collection
147 * Utilities to assist with garbage collection in an implementation
148 * that supports <em>strict pointer safety</em>.
149 * This implementation only supports <em>relaxed pointer safety</em>
150 * and so these functions have no effect.
152 * C++11 20.6.4 [util.dynamic.safety], Pointer safety
157 /// Constants representing the different types of pointer safety.
158 enum class pointer_safety { relaxed, preferred, strict };
160 /// Inform a garbage collector that an object is still in use.
162 declare_reachable(void*) { }
164 /// Unregister an object previously registered with declare_reachable.
165 template <typename _Tp>
167 undeclare_reachable(_Tp* __p) { return __p; }
169 /// Inform a garbage collector that a region of memory need not be traced.
171 declare_no_pointers(char*, size_t) { }
173 /// Unregister a range previously registered with declare_no_pointers.
175 undeclare_no_pointers(char*, size_t) { }
177 /// The type of pointer safety supported by the implementation.
178 inline pointer_safety
179 get_pointer_safety() noexcept { return pointer_safety::relaxed; }
182 #if __cplusplus > 201703L
183 /** @brief Inform the compiler that a pointer is aligned.
185 * @tparam _Align An alignment value (i.e. a power of two)
186 * @tparam _Tp An object type
187 * @param __ptr A pointer that is aligned to _Align
190 template<size_t _Align, class _Tp>
191 [[nodiscard,__gnu__::__always_inline__]]
192 constexpr _Tp* assume_aligned(_Tp* __ptr)
194 static_assert(std::has_single_bit(_Align));
195 _GLIBCXX_DEBUG_ASSERT((std::uintptr_t)__ptr % _Align == 0);
196 return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Align));
200 #if __cplusplus > 201703L
201 template<typename _Tp>
202 struct __is_pair : false_type { };
203 template<typename _Tp, typename _Up>
204 struct __is_pair<pair<_Tp, _Up>> : true_type { };
205 template<typename _Tp, typename _Up>
206 struct __is_pair<const pair<_Tp, _Up>> : true_type { };
208 /** @addtogroup allocators
211 template<typename _Tp, typename __ = _Require<__not_<__is_pair<_Tp>>>,
212 typename _Alloc, typename... _Args>
214 __uses_alloc_args(const _Alloc& __a, _Args&&... __args) noexcept
216 if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
218 if constexpr (is_constructible_v<_Tp, allocator_arg_t,
219 const _Alloc&, _Args...>)
221 return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
222 allocator_arg, __a, std::forward<_Args>(__args)...);
226 static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
227 "construction with an allocator must be possible"
228 " if uses_allocator is true");
230 return tuple<_Args&&..., const _Alloc&>(
231 std::forward<_Args>(__args)..., __a);
236 static_assert(is_constructible_v<_Tp, _Args...>);
238 return tuple<_Args&&...>(std::forward<_Args>(__args)...);
243 template<typename _Tp>
244 concept _Std_pair = __is_pair<_Tp>::value;
247 // This is a temporary workaround until -fconcepts is implied by -std=gnu++2a
249 # define _GLIBCXX_STD_PAIR_CONSTRAINT(T) _Std_pair T
250 # define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) _Std_pair T
252 # define _GLIBCXX_STD_PAIR_CONSTRAINT(T) \
253 typename T, typename __ = _Require<__is_pair<T>>
254 # define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) typename T, typename
257 template<typename _Tp,
259 typename __ = _Require<__not_<__is_pair<_Tp>>>,
261 typename _Alloc, typename... _Args>
263 uses_allocator_construction_args(const _Alloc& __a,
264 _Args&&... __args) noexcept
266 requires (! _Std_pair<_Tp>)
269 return std::__uses_alloc_args<_Tp>(__a, std::forward<_Args>(__args)...);
272 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
273 typename _Tuple1, typename _Tuple2>
275 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
276 _Tuple1&& __x, _Tuple2&& __y) noexcept;
278 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc>
280 uses_allocator_construction_args(const _Alloc&) noexcept;
282 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
283 typename _Up, typename _Vp>
285 uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
287 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
288 typename _Up, typename _Vp>
290 uses_allocator_construction_args(const _Alloc&,
291 const pair<_Up, _Vp>&) noexcept;
293 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
294 typename _Up, typename _Vp>
296 uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
298 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
299 typename _Tuple1, typename _Tuple2>
301 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
302 _Tuple1&& __x, _Tuple2&& __y) noexcept
304 using _Tp1 = typename _Tp::first_type;
305 using _Tp2 = typename _Tp::second_type;
307 return std::make_tuple(piecewise_construct,
308 std::apply([&__a](auto&&... __args1) {
309 return std::uses_allocator_construction_args<_Tp1>(
310 __a, std::forward<decltype(__args1)>(__args1)...);
311 }, std::forward<_Tuple1>(__x)),
312 std::apply([&__a](auto&&... __args2) {
313 return std::uses_allocator_construction_args<_Tp2>(
314 __a, std::forward<decltype(__args2)>(__args2)...);
315 }, std::forward<_Tuple2>(__y)));
318 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc>
320 uses_allocator_construction_args(const _Alloc& __a) noexcept
322 using _Tp1 = typename _Tp::first_type;
323 using _Tp2 = typename _Tp::second_type;
325 return std::make_tuple(piecewise_construct,
326 std::uses_allocator_construction_args<_Tp1>(__a),
327 std::uses_allocator_construction_args<_Tp2>(__a));
330 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
331 typename _Up, typename _Vp>
333 uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
336 using _Tp1 = typename _Tp::first_type;
337 using _Tp2 = typename _Tp::second_type;
339 return std::make_tuple(piecewise_construct,
340 std::uses_allocator_construction_args<_Tp1>(__a,
341 std::forward<_Up>(__u)),
342 std::uses_allocator_construction_args<_Tp2>(__a,
343 std::forward<_Vp>(__v)));
346 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
347 typename _Up, typename _Vp>
349 uses_allocator_construction_args(const _Alloc& __a,
350 const pair<_Up, _Vp>& __pr) noexcept
352 using _Tp1 = typename _Tp::first_type;
353 using _Tp2 = typename _Tp::second_type;
355 return std::make_tuple(piecewise_construct,
356 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
357 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
360 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
361 typename _Up, typename _Vp>
363 uses_allocator_construction_args(const _Alloc& __a,
364 pair<_Up, _Vp>&& __pr) noexcept
366 using _Tp1 = typename _Tp::first_type;
367 using _Tp2 = typename _Tp::second_type;
369 return std::make_tuple(piecewise_construct,
370 std::uses_allocator_construction_args<_Tp1>(__a,
371 std::move(__pr).first),
372 std::uses_allocator_construction_args<_Tp2>(__a,
373 std::move(__pr).second));
376 template<typename _Tp, typename _Alloc, typename... _Args>
378 make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
380 return std::make_from_tuple<_Tp>(
381 std::uses_allocator_construction_args<_Tp>(__a,
382 std::forward<_Args>(__args)...));
385 template<typename _Tp, typename _Alloc, typename... _Args>
387 uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
390 return std::apply([&](auto&&... __xs) {
391 return std::construct_at(__p, std::forward<decltype(__xs)>(__xs)...);
392 }, std::uses_allocator_construction_args<_Tp>(__a,
393 std::forward<_Args>(__args)...));
399 _GLIBCXX_END_NAMESPACE_VERSION
403 #if __cplusplus > 201402L
404 // Parallel STL algorithms
405 # if _PSTL_EXECUTION_POLICIES_DEFINED
406 // If <execution> has already been included, pull in implementations
407 # include <pstl/glue_memory_impl.h>
409 // Otherwise just pull in forward declarations
410 # include <pstl/glue_memory_defs.h>
413 // Feature test macro for parallel algorithms
414 # define __cpp_lib_parallel_algorithm 201603L
417 #endif /* _GLIBCXX_MEMORY */