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1 : // Guarded Allocation -*- C++ -*- 2 : 3 : // Copyright (C) 2014-2019 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 48256290 : __allocated_ptr(_Alloc& __a, pointer __ptr) noexcept 53 48257245 : : _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 48257245 : ~__allocated_ptr() 71 : { 72 : if (_M_ptr != nullptr) 73 48256290 : std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1); 74 : } 75 : 76 : /// Release ownership of the owned pointer 77 : __allocated_ptr& 78 48256290 : operator=(std::nullptr_t) noexcept 79 : { 80 48256290 : _M_ptr = nullptr; 81 : return *this; 82 : } 83 : 84 : /// Get the address that the owned pointer refers to. 85 955 : value_type* get() { return std::__to_address(_M_ptr); } 86 : 87 : private: 88 : _Alloc* _M_alloc; 89 : pointer _M_ptr; 90 : }; 91 : 92 : /// Allocate space for a single object using __a 93 : template<typename _Alloc> 94 : __allocated_ptr<_Alloc> 95 955 : __allocate_guarded(_Alloc& __a) 96 : { 97 955 : return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) }; 98 : } 99 : 100 : _GLIBCXX_END_NAMESPACE_VERSION 101 : } // namespace std 102 : 103 : #endif 104 : #endif