allocated_ptr.h source code [include/c++/7/bits/allocated

1	// Guarded Allocation -- C++ --
2
3	// Copyright (C) 2014-2017 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
44	/// Non-standard RAII type for managing pointers obtained from allocators.
45	template<typename _Alloc>
46	struct __allocated_ptr
47	{
48	using pointer = typename allocator_traits<_Alloc>::pointer;
49	using value_type = typename allocator_traits<_Alloc>::value_type;
50
51	/// Take ownership of __ptr
52	__allocated_ptr(_Alloc& __a, pointer __ptr) noexcept
53	: _M_alloc(std::__addressof(__a)), _M_ptr(__ptr)
54	{ }
55
56	/// Convert __ptr to allocator's pointer type and take ownership of it
57	template<typename _Ptr,
58	typename _Req = _Require<is_same<_Ptr, value_type*>>>
59	__allocated_ptr(_Alloc& __a, _Ptr __ptr)
60	: _M_alloc(std::__addressof(__a)),
61	_M_ptr(pointer_traits<pointer>::pointer_to(*__ptr))
62	{ }
63
64	/// Transfer ownership of the owned pointer
65	__allocated_ptr(__allocated_ptr&& __gd) noexcept
66	: _M_alloc(__gd._M_alloc), _M_ptr(__gd._M_ptr)
67	{ __gd._M_ptr = nullptr; }
68
69	/// Deallocate the owned pointer
70	~__allocated_ptr()
71	{
72	if (_M_ptr != nullptr)
73	std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1);
74	}
75
76	/// Release ownership of the owned pointer
77	__allocated_ptr&
78	operator=(std::nullptr_t) noexcept
79	{
80	_M_ptr = nullptr;
81	return *this;
82	}
83
84	/// Get the address that the owned pointer refers to.
85	value_type* get() { return _S_raw_ptr(_M_ptr); }
86
87	private:
88	static value_type* _S_raw_ptr(value_type* __ptr) { return __ptr; }
89
90	template<typename _Ptr>
91	static auto
92	_S_raw_ptr(_Ptr __ptr) -> decltype(_S_raw_ptr(__ptr.operator->()))
93	{ return _S_raw_ptr(__ptr.operator->()); }
94
95	_Alloc* _M_alloc;
96	pointer _M_ptr;
97	};
98
99	/// Allocate space for a single object using __a
100	template<typename _Alloc>
101	__allocated_ptr<_Alloc>
102	__allocate_guarded(_Alloc& __a)
103	{
104	return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) };
105	}
106
107	_GLIBCXX_END_NAMESPACE_VERSION
108	} // namespace std
109
110	#endif
111	#endif
112

std::__allocated_ptr::get

std::__allocated_ptr::_S_raw_ptr

std::__allocated_ptr::_M_alloc

std::__allocated_ptr::_M_ptr

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