1 | // Guarded Allocation -*- C++ -*- |
2 | |
3 | // Copyright (C) 2014-2021 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 | /** @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 |
43 | /// @cond undocumented |
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 |
54 | : _M_alloc(std::__addressof(__a)), _M_ptr(__ptr) |
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) |
61 | : _M_alloc(std::__addressof(__a)), |
62 | _M_ptr(pointer_traits<pointer>::pointer_to(*__ptr)) |
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 |
78 | __allocated_ptr& |
79 | operator=(std::nullptr_t) noexcept |
80 | { |
81 | _M_ptr = nullptr; |
82 | return *this; |
83 | } |
84 | |
85 | /// Get the address that the owned pointer refers to. |
86 | value_type* get() { return std::__to_address(_M_ptr); } |
87 | |
88 | private: |
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 | |
101 | /// @endcond |
102 | _GLIBCXX_END_NAMESPACE_VERSION |
103 | } // namespace std |
104 | |
105 | #endif |
106 | #endif |
107 | |