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1 | // Guarded Allocation -*- C++ -*- |
2 | ||
a945c346 | 3 | // Copyright (C) 2014-2024 Free Software Foundation, Inc. |
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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 | /** @file bits/allocated_ptr.h | |
26 | * This is an internal header file, included by other library headers. | |
27 | * Do not attempt to use it directly. @headername{memory} | |
28 | */ | |
29 | ||
30 | #ifndef _ALLOCATED_PTR_H | |
31 | #define _ALLOCATED_PTR_H 1 | |
32 | ||
33 | #if __cplusplus < 201103L | |
34 | # include <bits/c++0xwarning.h> | |
35 | #else | |
36 | # include <type_traits> | |
37 | # include <bits/ptr_traits.h> | |
38 | # include <bits/alloc_traits.h> | |
39 | ||
40 | namespace std _GLIBCXX_VISIBILITY(default) | |
41 | { | |
42 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
6667d5fe | 43 | /// @cond undocumented |
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44 | |
45 | /// Non-standard RAII type for managing pointers obtained from allocators. | |
46 | template<typename _Alloc> | |
47 | struct __allocated_ptr | |
48 | { | |
49 | using pointer = typename allocator_traits<_Alloc>::pointer; | |
50 | using value_type = typename allocator_traits<_Alloc>::value_type; | |
51 | ||
52 | /// Take ownership of __ptr | |
53 | __allocated_ptr(_Alloc& __a, pointer __ptr) noexcept | |
91b142ff | 54 | : _M_alloc(std::__addressof(__a)), _M_ptr(__ptr) |
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55 | { } |
56 | ||
57 | /// Convert __ptr to allocator's pointer type and take ownership of it | |
58 | template<typename _Ptr, | |
59 | typename _Req = _Require<is_same<_Ptr, value_type*>>> | |
60 | __allocated_ptr(_Alloc& __a, _Ptr __ptr) | |
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61 | : _M_alloc(std::__addressof(__a)), |
62 | _M_ptr(pointer_traits<pointer>::pointer_to(*__ptr)) | |
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63 | { } |
64 | ||
65 | /// Transfer ownership of the owned pointer | |
66 | __allocated_ptr(__allocated_ptr&& __gd) noexcept | |
67 | : _M_alloc(__gd._M_alloc), _M_ptr(__gd._M_ptr) | |
68 | { __gd._M_ptr = nullptr; } | |
69 | ||
70 | /// Deallocate the owned pointer | |
71 | ~__allocated_ptr() | |
72 | { | |
73 | if (_M_ptr != nullptr) | |
74 | std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1); | |
75 | } | |
76 | ||
77 | /// Release ownership of the owned pointer | |
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78 | __allocated_ptr& |
79 | operator=(std::nullptr_t) noexcept | |
80 | { | |
81 | _M_ptr = nullptr; | |
82 | return *this; | |
83 | } | |
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84 | |
85 | /// Get the address that the owned pointer refers to. | |
2af96386 | 86 | value_type* get() { return std::__to_address(_M_ptr); } |
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87 | |
88 | private: | |
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89 | _Alloc* _M_alloc; |
90 | pointer _M_ptr; | |
91 | }; | |
92 | ||
93 | /// Allocate space for a single object using __a | |
94 | template<typename _Alloc> | |
95 | __allocated_ptr<_Alloc> | |
96 | __allocate_guarded(_Alloc& __a) | |
97 | { | |
98 | return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) }; | |
99 | } | |
100 | ||
6667d5fe | 101 | /// @endcond |
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102 | _GLIBCXX_END_NAMESPACE_VERSION |
103 | } // namespace std | |
104 | ||
105 | #endif | |
106 | #endif |