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107 lines
3.3 KiB
107 lines
3.3 KiB
3 years ago
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// Guarded Allocation -*- C++ -*-
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// Copyright (C) 2014-2021 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file bits/allocated_ptr.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{memory}
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*/
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#ifndef _ALLOCATED_PTR_H
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#define _ALLOCATED_PTR_H 1
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#if __cplusplus < 201103L
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# include <bits/c++0xwarning.h>
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#else
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# include <type_traits>
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# include <bits/ptr_traits.h>
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# include <bits/alloc_traits.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/// @cond undocumented
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/// Non-standard RAII type for managing pointers obtained from allocators.
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template<typename _Alloc>
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struct __allocated_ptr
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{
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using pointer = typename allocator_traits<_Alloc>::pointer;
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using value_type = typename allocator_traits<_Alloc>::value_type;
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/// Take ownership of __ptr
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__allocated_ptr(_Alloc& __a, pointer __ptr) noexcept
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: _M_alloc(std::__addressof(__a)), _M_ptr(__ptr)
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{ }
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/// Convert __ptr to allocator's pointer type and take ownership of it
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template<typename _Ptr,
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typename _Req = _Require<is_same<_Ptr, value_type*>>>
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__allocated_ptr(_Alloc& __a, _Ptr __ptr)
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: _M_alloc(std::__addressof(__a)),
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_M_ptr(pointer_traits<pointer>::pointer_to(*__ptr))
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{ }
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/// Transfer ownership of the owned pointer
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__allocated_ptr(__allocated_ptr&& __gd) noexcept
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: _M_alloc(__gd._M_alloc), _M_ptr(__gd._M_ptr)
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{ __gd._M_ptr = nullptr; }
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/// Deallocate the owned pointer
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~__allocated_ptr()
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{
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if (_M_ptr != nullptr)
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std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1);
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}
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/// Release ownership of the owned pointer
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__allocated_ptr&
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operator=(std::nullptr_t) noexcept
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{
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_M_ptr = nullptr;
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return *this;
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}
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/// Get the address that the owned pointer refers to.
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value_type* get() { return std::__to_address(_M_ptr); }
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private:
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_Alloc* _M_alloc;
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pointer _M_ptr;
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};
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/// Allocate space for a single object using __a
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template<typename _Alloc>
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__allocated_ptr<_Alloc>
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__allocate_guarded(_Alloc& __a)
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{
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return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) };
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}
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/// @endcond
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif
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#endif
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