3// Copyright (C) 2001-2019 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.
43#ifndef _GLIBCXX_MEMORY
44#define _GLIBCXX_MEMORY 1
46#pragma GCC system_header
49 * @defgroup memory Memory
52 * Components for memory allocation, deallocation, and management.
56 * @defgroup pointer_abstractions Pointer Abstractions
59 * Smart pointers, etc.
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>
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>
87# include <backward/auto_ptr.h>
90#if __cplusplus >= 201103L
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
97namespace std _GLIBCXX_VISIBILITY(default)
99_GLIBCXX_BEGIN_NAMESPACE_VERSION
102 * @brief Fit aligned storage in buffer.
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.
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.
118align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
120#ifdef _GLIBCXX_USE_C99_STDINT_TR1
121 const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
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);
128 const auto __aligned = (__intptr - 1u + __align) & -__align;
129 const auto __diff = __aligned - __intptr;
130 if ((__size + __diff) > __space)
135 return __ptr = reinterpret_cast<void*>(__aligned);
139// 20.7.4 [util.dynamic.safety], pointer safety
141enum class pointer_safety { relaxed, preferred, strict };
144declare_reachable(void*) { }
146template <typename _Tp>
148 undeclare_reachable(_Tp* __p) { return __p; }
151declare_no_pointers(char*, size_t) { }
154undeclare_no_pointers(char*, size_t) { }
157get_pointer_safety() noexcept { return pointer_safety::relaxed; }
159#if __cplusplus > 201703L
160#define __cpp_lib_assume_aligned 201811L
161 /** @brief Inform the compiler that a pointer is aligned.
163 * @tparam _Align An alignment value (i.e. a power of two)
164 * @tparam _Tp An object type
165 * @param __ptr A pointer that is aligned to _Align
167 * C++20 20.10.6 [ptr.align]
171 template<size_t _Align, class _Tp>
172 [[nodiscard,__gnu__::__always_inline__]]
174 assume_aligned(_Tp* __ptr) noexcept
176 static_assert(std::ispow2(_Align));
177 if (std::is_constant_evaluated())
181 // This function is expected to be used in hot code, where
182 // __glibcxx_assert would add unwanted overhead.
183 _GLIBCXX_DEBUG_ASSERT((std::uintptr_t)__ptr % _Align == 0);
184 return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Align));
189#if __cplusplus > 201703L
190 template<typename _Tp>
191 struct __is_pair : false_type { };
192 template<typename _Tp, typename _Up>
193 struct __is_pair<pair<_Tp, _Up>> : true_type { };
194 template<typename _Tp, typename _Up>
195 struct __is_pair<const pair<_Tp, _Up>> : true_type { };
197 template<typename _Tp, typename __ = _Require<__not_<__is_pair<_Tp>>>,
198 typename _Alloc, typename... _Args>
200 __uses_alloc_args(const _Alloc& __a, _Args&&... __args) noexcept
202 if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
204 if constexpr (is_constructible_v<_Tp, allocator_arg_t,
205 const _Alloc&, _Args...>)
207 return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
208 allocator_arg, __a, std::forward<_Args>(__args)...);
212 static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
213 "construction with an allocator must be possible"
214 " if uses_allocator is true");
216 return tuple<_Args&&..., const _Alloc&>(
217 std::forward<_Args>(__args)..., __a);
222 static_assert(is_constructible_v<_Tp, _Args...>);
224 return tuple<_Args&&...>(std::forward<_Args>(__args)...);
229 template<typename _Tp>
230 concept _Std_pair = __is_pair<_Tp>::value;
233// This is a temporary workaround until -fconcepts is implied by -std=gnu++2a
235# define _GLIBCXX_STD_PAIR_CONSTRAINT(T) _Std_pair T
236# define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) _Std_pair T
238# define _GLIBCXX_STD_PAIR_CONSTRAINT(T) \
239 typename T, typename __ = _Require<__is_pair<T>>
240# define _GLIBCXX_STD_PAIR_CONSTRAINT_(T) typename T, typename
243 template<typename _Tp,
245 typename __ = _Require<__not_<__is_pair<_Tp>>>,
247 typename _Alloc, typename... _Args>
249 uses_allocator_construction_args(const _Alloc& __a,
250 _Args&&... __args) noexcept
252 requires (! _Std_pair<_Tp>)
255 return std::__uses_alloc_args<_Tp>(__a, std::forward<_Args>(__args)...);
258 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
259 typename _Tuple1, typename _Tuple2>
261 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
262 _Tuple1&& __x, _Tuple2&& __y) noexcept;
264 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc>
266 uses_allocator_construction_args(const _Alloc&) noexcept;
268 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
269 typename _Up, typename _Vp>
271 uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
273 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
274 typename _Up, typename _Vp>
276 uses_allocator_construction_args(const _Alloc&,
277 const pair<_Up, _Vp>&) noexcept;
279 template<_GLIBCXX_STD_PAIR_CONSTRAINT(_Tp), typename _Alloc,
280 typename _Up, typename _Vp>
282 uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
284 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
285 typename _Tuple1, typename _Tuple2>
287 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
288 _Tuple1&& __x, _Tuple2&& __y) noexcept
290 using _Tp1 = typename _Tp::first_type;
291 using _Tp2 = typename _Tp::second_type;
293 return std::make_tuple(piecewise_construct,
294 std::apply([&__a](auto&&... __args1) {
295 return std::uses_allocator_construction_args<_Tp1>(
296 __a, std::forward<decltype(__args1)>(__args1)...);
297 }, std::forward<_Tuple1>(__x)),
298 std::apply([&__a](auto&&... __args2) {
299 return std::uses_allocator_construction_args<_Tp2>(
300 __a, std::forward<decltype(__args2)>(__args2)...);
301 }, std::forward<_Tuple2>(__y)));
304 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc>
306 uses_allocator_construction_args(const _Alloc& __a) noexcept
308 using _Tp1 = typename _Tp::first_type;
309 using _Tp2 = typename _Tp::second_type;
311 return std::make_tuple(piecewise_construct,
312 std::uses_allocator_construction_args<_Tp1>(__a),
313 std::uses_allocator_construction_args<_Tp2>(__a));
316 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
317 typename _Up, typename _Vp>
319 uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
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::forward<_Up>(__u)),
328 std::uses_allocator_construction_args<_Tp2>(__a,
329 std::forward<_Vp>(__v)));
332 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
333 typename _Up, typename _Vp>
335 uses_allocator_construction_args(const _Alloc& __a,
336 const pair<_Up, _Vp>& __pr) noexcept
338 using _Tp1 = typename _Tp::first_type;
339 using _Tp2 = typename _Tp::second_type;
341 return std::make_tuple(piecewise_construct,
342 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
343 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
346 template<_GLIBCXX_STD_PAIR_CONSTRAINT_(_Tp), typename _Alloc,
347 typename _Up, typename _Vp>
349 uses_allocator_construction_args(const _Alloc& __a,
350 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,
357 std::move(__pr).first),
358 std::uses_allocator_construction_args<_Tp2>(__a,
359 std::move(__pr).second));
362 template<typename _Tp, typename _Alloc, typename... _Args>
364 make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
366 return std::make_from_tuple<_Tp>(
367 std::uses_allocator_construction_args<_Tp>(__a,
368 std::forward<_Args>(__args)...));
371 template<typename _Tp, typename _Alloc, typename... _Args>
373 uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
376 void* __vp = const_cast<void*>(static_cast<const volatile void*>(__p));
377 return ::new(__vp) _Tp(std::make_obj_using_allocator<_Tp>(__a,
378 std::forward<_Args>(__args)...));
383_GLIBCXX_END_NAMESPACE_VERSION
387#if __cplusplus > 201402L
388// Parallel STL algorithms
389# if __PSTL_EXECUTION_POLICIES_DEFINED
390// If <execution> has already been included, pull in implementations
391# include <pstl/glue_memory_impl.h>
393// Otherwise just pull in forward declarations
394# include <pstl/glue_memory_defs.h>
397// Feature test macro for parallel algorithms
398# define __cpp_lib_parallel_algorithm 201603L
401#endif /* _GLIBCXX_MEMORY */