node_handle.h
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// Node handles for containers -*- C++ -*-
// Copyright (C) 2016-2018 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/node_handle.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly.
* @headername{map,set,unordered_map,unordered_set}
*/
#ifndef _NODE_HANDLE
#define _NODE_HANDLE 1
#pragma GCC system_header
#if __cplusplus > 201402L
# define __cpp_lib_node_extract 201606
#include <optional>
#include <bits/alloc_traits.h>
#include <bits/ptr_traits.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/// Base class for node handle types of maps and sets.
template<typename _Val, typename _NodeAlloc>
class _Node_handle_common
{
using _AllocTraits = allocator_traits<_NodeAlloc>;
public:
using allocator_type = __alloc_rebind<_NodeAlloc, _Val>;
allocator_type
get_allocator() const noexcept
{
__glibcxx_assert(!this->empty());
return allocator_type(*_M_alloc);
}
explicit operator bool() const noexcept { return _M_ptr != nullptr; }
[[nodiscard]] bool empty() const noexcept { return _M_ptr == nullptr; }
protected:
constexpr _Node_handle_common() noexcept : _M_ptr(), _M_alloc() {}
~_Node_handle_common() { _M_destroy(); }
_Node_handle_common(_Node_handle_common&& __nh) noexcept
: _M_ptr(__nh._M_ptr), _M_alloc(std::move(__nh._M_alloc))
{
__nh._M_ptr = nullptr;
__nh._M_alloc = nullopt;
}
_Node_handle_common&
operator=(_Node_handle_common&& __nh) noexcept
{
_M_destroy();
_M_ptr = __nh._M_ptr;
if constexpr (is_move_assignable_v<_NodeAlloc>)
{
if (_AllocTraits::propagate_on_container_move_assignment::value
|| !this->_M_alloc)
this->_M_alloc = std::move(__nh._M_alloc);
else
{
__glibcxx_assert(this->_M_alloc == __nh._M_alloc);
}
}
else
{
__glibcxx_assert(_M_alloc);
}
__nh._M_ptr = nullptr;
__nh._M_alloc = nullopt;
return *this;
}
_Node_handle_common(typename _AllocTraits::pointer __ptr,
const _NodeAlloc& __alloc)
: _M_ptr(__ptr), _M_alloc(__alloc) { }
void
_M_swap(_Node_handle_common& __nh) noexcept
{
using std::swap;
swap(_M_ptr, __nh._M_ptr);
if (_AllocTraits::propagate_on_container_swap
|| !_M_alloc || !__nh._M_alloc)
_M_alloc.swap(__nh._M_alloc);
else
{
__glibcxx_assert(_M_alloc == __nh._M_alloc);
}
}
private:
void
_M_destroy() noexcept
{
if (_M_ptr != nullptr)
{
allocator_type __alloc(*_M_alloc);
allocator_traits<allocator_type>::destroy(__alloc,
_M_ptr->_M_valptr());
_AllocTraits::deallocate(*_M_alloc, _M_ptr, 1);
}
}
protected:
typename _AllocTraits::pointer _M_ptr;
private:
optional<_NodeAlloc> _M_alloc;
template<typename _Key2, typename _Value2, typename _KeyOfValue,
typename _Compare, typename _ValueAlloc>
friend class _Rb_tree;
};
/// Node handle type for maps.
template<typename _Key, typename _Value, typename _NodeAlloc>
class _Node_handle : public _Node_handle_common<_Value, _NodeAlloc>
{
public:
constexpr _Node_handle() noexcept = default;
~_Node_handle() = default;
_Node_handle(_Node_handle&&) noexcept = default;
_Node_handle&
operator=(_Node_handle&&) noexcept = default;
using key_type = _Key;
using mapped_type = typename _Value::second_type;
key_type&
key() const noexcept
{
__glibcxx_assert(!this->empty());
return *_M_pkey;
}
mapped_type&
mapped() const noexcept
{
__glibcxx_assert(!this->empty());
return *_M_pmapped;
}
void
swap(_Node_handle& __nh) noexcept
{
this->_M_swap(__nh);
using std::swap;
swap(_M_pkey, __nh._M_pkey);
swap(_M_pmapped, __nh._M_pmapped);
}
friend void
swap(_Node_handle& __x, _Node_handle& __y)
noexcept(noexcept(__x.swap(__y)))
{ __x.swap(__y); }
private:
using _AllocTraits = allocator_traits<_NodeAlloc>;
_Node_handle(typename _AllocTraits::pointer __ptr,
const _NodeAlloc& __alloc)
: _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc)
{
if (__ptr)
{
auto& __key = const_cast<_Key&>(__ptr->_M_valptr()->first);
_M_pkey = _S_pointer_to(__key);
_M_pmapped = _S_pointer_to(__ptr->_M_valptr()->second);
}
else
{
_M_pkey = nullptr;
_M_pmapped = nullptr;
}
}
template<typename _Tp>
using __pointer
= __ptr_rebind<typename _AllocTraits::pointer,
remove_reference_t<_Tp>>;
__pointer<_Key> _M_pkey = nullptr;
__pointer<typename _Value::second_type> _M_pmapped = nullptr;
template<typename _Tp>
__pointer<_Tp>
_S_pointer_to(_Tp& __obj)
{ return pointer_traits<__pointer<_Tp>>::pointer_to(__obj); }
const key_type&
_M_key() const noexcept { return key(); }
template<typename _Key2, typename _Value2, typename _KeyOfValue,
typename _Compare, typename _ValueAlloc>
friend class _Rb_tree;
template<typename _Key2, typename _Value2, typename _ValueAlloc,
typename _ExtractKey, typename _Equal,
typename _H1, typename _H2, typename _Hash,
typename _RehashPolicy, typename _Traits>
friend class _Hashtable;
};
/// Node handle type for sets.
template<typename _Value, typename _NodeAlloc>
class _Node_handle<_Value, _Value, _NodeAlloc>
: public _Node_handle_common<_Value, _NodeAlloc>
{
public:
constexpr _Node_handle() noexcept = default;
~_Node_handle() = default;
_Node_handle(_Node_handle&&) noexcept = default;
_Node_handle&
operator=(_Node_handle&&) noexcept = default;
using value_type = _Value;
value_type&
value() const noexcept
{
__glibcxx_assert(!this->empty());
return *this->_M_ptr->_M_valptr();
}
void
swap(_Node_handle& __nh) noexcept
{ this->_M_swap(__nh); }
friend void
swap(_Node_handle& __x, _Node_handle& __y)
noexcept(noexcept(__x.swap(__y)))
{ __x.swap(__y); }
private:
using _AllocTraits = allocator_traits<_NodeAlloc>;
_Node_handle(typename _AllocTraits::pointer __ptr,
const _NodeAlloc& __alloc)
: _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc) { }
const value_type&
_M_key() const noexcept { return value(); }
template<typename _Key, typename _Val, typename _KeyOfValue,
typename _Compare, typename _Alloc>
friend class _Rb_tree;
template<typename _Key2, typename _Value2, typename _ValueAlloc,
typename _ExtractKey, typename _Equal,
typename _H1, typename _H2, typename _Hash,
typename _RehashPolicy, typename _Traits>
friend class _Hashtable;
};
/// Return type of insert(node_handle&&) on unique maps/sets.
template<typename _Iterator, typename _NodeHandle>
struct _Node_insert_return
{
_Iterator position = _Iterator();
bool inserted = false;
_NodeHandle node;
};
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++17
#endif
std::experimental::fundamentals_v1::nullopt
constexpr nullopt_t nullopt
Tag to disengage optional objects.
Definition: optional:107
optional
alloc_traits.h
std::__ptr_rebind
typename pointer_traits< _Ptr >::template rebind< _Tp > __ptr_rebind
Convenience alias for rebinding pointers.
Definition: ptr_traits.h:147
ptr_traits.h
std
ISO C++ entities toplevel namespace is std.
std::allocator_traits::destroy
static void destroy(_Alloc &__a, _Tp *__p)
Destroy an object of type _Tp.
Definition: bits/alloc_traits.h:355