| // Node handles for containers -*- C++ -*- |
| |
| // Copyright (C) 2016-2022 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/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 >= 201703L |
| # define __cpp_lib_node_extract 201606L |
| |
| #include <new> |
| #include <bits/alloc_traits.h> |
| #include <bits/ptr_traits.h> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| /** |
| * @defgroup node_handles Node handles |
| * @ingroup associative_containers |
| * @since C++17 |
| * |
| * The associative containers (`map`, `set`, `multimap` and `multiset`) |
| * support extracting and re-inserting nodes from the container. Those |
| * operations use the container's `node_handle` type, which is an alias |
| * for a `_Node_handle<...>` type. You should always use the container's |
| * `node_handle` type (e.g. `std::set<int>::node_handle`) to refer to |
| * these types, not the non-standard internal `_Node_handle` names. |
| * |
| * @{ |
| */ |
| |
| /// 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._M_alloc); |
| } |
| |
| explicit operator bool() const noexcept { return _M_ptr != nullptr; } |
| |
| [[nodiscard]] bool empty() const noexcept { return _M_ptr == nullptr; } |
| |
| /// @cond undocumented |
| protected: |
| constexpr _Node_handle_common() noexcept : _M_ptr() { } |
| |
| ~_Node_handle_common() |
| { |
| if (!empty()) |
| _M_reset(); |
| } |
| |
| _Node_handle_common(_Node_handle_common&& __nh) noexcept |
| : _M_ptr(__nh._M_ptr) |
| { |
| if (_M_ptr) |
| _M_move(std::move(__nh)); |
| } |
| |
| _Node_handle_common& |
| operator=(_Node_handle_common&& __nh) noexcept |
| { |
| if (empty()) |
| { |
| if (!__nh.empty()) |
| _M_move(std::move(__nh)); |
| } |
| else if (__nh.empty()) |
| _M_reset(); |
| else |
| { |
| // Free the current node before replacing the allocator. |
| _AllocTraits::destroy(*_M_alloc, _M_ptr->_M_valptr()); |
| _AllocTraits::deallocate(*_M_alloc, _M_ptr, 1); |
| |
| _M_alloc = __nh._M_alloc.release(); // assigns if POCMA |
| _M_ptr = __nh._M_ptr; |
| __nh._M_ptr = nullptr; |
| } |
| return *this; |
| } |
| |
| _Node_handle_common(typename _AllocTraits::pointer __ptr, |
| const _NodeAlloc& __alloc) |
| : _M_ptr(__ptr), _M_alloc(__alloc) |
| { |
| __glibcxx_assert(__ptr != nullptr); |
| } |
| |
| void |
| _M_swap(_Node_handle_common& __nh) noexcept |
| { |
| if (empty()) |
| { |
| if (!__nh.empty()) |
| _M_move(std::move(__nh)); |
| } |
| else if (__nh.empty()) |
| __nh._M_move(std::move(*this)); |
| else |
| { |
| using std::swap; |
| swap(_M_ptr, __nh._M_ptr); |
| _M_alloc.swap(__nh._M_alloc); // swaps if POCS |
| } |
| } |
| |
| private: |
| // Moves the pointer and allocator from __nh to *this. |
| // Precondition: empty() && !__nh.empty() |
| // Postcondition: !empty() && __nh.empty() |
| void |
| _M_move(_Node_handle_common&& __nh) noexcept |
| { |
| ::new (std::__addressof(_M_alloc)) _NodeAlloc(__nh._M_alloc.release()); |
| _M_ptr = __nh._M_ptr; |
| __nh._M_ptr = nullptr; |
| } |
| |
| // Deallocates the node, destroys the allocator. |
| // Precondition: !empty() |
| // Postcondition: empty() |
| void |
| _M_reset() noexcept |
| { |
| _NodeAlloc __alloc = _M_alloc.release(); |
| _AllocTraits::destroy(__alloc, _M_ptr->_M_valptr()); |
| _AllocTraits::deallocate(__alloc, _M_ptr, 1); |
| _M_ptr = nullptr; |
| } |
| |
| protected: |
| typename _AllocTraits::pointer _M_ptr; |
| |
| private: |
| // A simplified, non-copyable std::optional<_NodeAlloc>. |
| // Call release() before destruction iff the allocator member is active. |
| union _Optional_alloc |
| { |
| _Optional_alloc() { } |
| ~_Optional_alloc() { } |
| |
| _Optional_alloc(_Optional_alloc&&) = delete; |
| _Optional_alloc& operator=(_Optional_alloc&&) = delete; |
| |
| _Optional_alloc(const _NodeAlloc& __alloc) noexcept |
| : _M_alloc(__alloc) |
| { } |
| |
| // Precondition: _M_alloc is the active member of the union. |
| void |
| operator=(_NodeAlloc&& __alloc) noexcept |
| { |
| using _ATr = _AllocTraits; |
| if constexpr (_ATr::propagate_on_container_move_assignment::value) |
| _M_alloc = std::move(__alloc); |
| else if constexpr (!_AllocTraits::is_always_equal::value) |
| __glibcxx_assert(_M_alloc == __alloc); |
| } |
| |
| // Precondition: _M_alloc is the active member of both unions. |
| void |
| swap(_Optional_alloc& __other) noexcept |
| { |
| using std::swap; |
| if constexpr (_AllocTraits::propagate_on_container_swap::value) |
| swap(_M_alloc, __other._M_alloc); |
| else if constexpr (!_AllocTraits::is_always_equal::value) |
| __glibcxx_assert(_M_alloc == __other._M_alloc); |
| } |
| |
| // Precondition: _M_alloc is the active member of the union. |
| _NodeAlloc& operator*() noexcept { return _M_alloc; } |
| |
| // Precondition: _M_alloc is the active member of the union. |
| _NodeAlloc release() noexcept |
| { |
| _NodeAlloc __tmp = std::move(_M_alloc); |
| _M_alloc.~_NodeAlloc(); |
| return __tmp; |
| } |
| |
| struct _Empty { }; |
| |
| [[__no_unique_address__]] _Empty _M_empty; |
| [[__no_unique_address__]] _NodeAlloc _M_alloc; |
| }; |
| |
| [[__no_unique_address__]] _Optional_alloc _M_alloc; |
| |
| template<typename _Key2, typename _Value2, typename _KeyOfValue, |
| typename _Compare, typename _ValueAlloc> |
| friend class _Rb_tree; |
| |
| /// @endcond |
| }; |
| |
| /// 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 _Hash, typename _RangeHash, typename _Unused, |
| 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 _Hash, typename _RangeHash, typename _Unused, |
| 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 |