allocated_ptr.h
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// Guarded Allocation -*- C++ -*-
// Copyright (C) 2014-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/allocated_ptr.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{memory}
*/
#ifndef _ALLOCATED_PTR_H
#define _ALLOCATED_PTR_H 1
#if __cplusplus < 201103L
# include <bits/c++0xwarning.h>
#else
# include <type_traits>
# include <bits/ptr_traits.h>
# include <bits/alloc_traits.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/// @cond undocumented
/// Non-standard RAII type for managing pointers obtained from allocators.
template<typename _Alloc>
struct __allocated_ptr
{
using pointer = typename allocator_traits<_Alloc>::pointer;
using value_type = typename allocator_traits<_Alloc>::value_type;
/// Take ownership of __ptr
__allocated_ptr(_Alloc& __a, pointer __ptr) noexcept
: _M_alloc(std::__addressof(__a)), _M_ptr(__ptr)
{ }
/// Convert __ptr to allocator's pointer type and take ownership of it
template<typename _Ptr,
typename _Req = _Require<is_same<_Ptr, value_type*>>>
__allocated_ptr(_Alloc& __a, _Ptr __ptr)
: _M_alloc(std::__addressof(__a)),
_M_ptr(pointer_traits<pointer>::pointer_to(*__ptr))
{ }
/// Transfer ownership of the owned pointer
__allocated_ptr(__allocated_ptr&& __gd) noexcept
: _M_alloc(__gd._M_alloc), _M_ptr(__gd._M_ptr)
{ __gd._M_ptr = nullptr; }
/// Deallocate the owned pointer
~__allocated_ptr()
{
if (_M_ptr != nullptr)
std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1);
}
/// Release ownership of the owned pointer
__allocated_ptr&
operator=(std::nullptr_t) noexcept
{
_M_ptr = nullptr;
return *this;
}
/// Get the address that the owned pointer refers to.
value_type* get() { return std::__to_address(_M_ptr); }
private:
_Alloc* _M_alloc;
pointer _M_ptr;
};
/// Allocate space for a single object using __a
template<typename _Alloc>
__allocated_ptr<_Alloc>
__allocate_guarded(_Alloc& __a)
{
return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) };
}
/// @endcond
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif
#endif
ptr_traits.h
std::__addressof
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:49
std
ISO C++ entities toplevel namespace is std.
std::allocator_traits::pointer
__detected_or_t< value_type *, __pointer, _Alloc > pointer
The allocator's pointer type.
Definition: bits/alloc_traits.h:102
std::allocator_traits::allocate
static constexpr pointer allocate(_Alloc &__a, size_type __n)
Allocate memory.
Definition: bits/alloc_traits.h:317
std::allocator_traits::value_type
_Alloc::value_type value_type
The allocated type.
Definition: bits/alloc_traits.h:95
std::allocator_traits::deallocate
static constexpr void deallocate(_Alloc &__a, pointer __p, size_type __n)
Deallocate memory.
Definition: bits/alloc_traits.h:344
alloc_traits.h
type_traits