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// Node handles for containers -*- C++ -*- |
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|
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// Copyright (C) 2016-2021 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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|
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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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|
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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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|
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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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|
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/** @file bits/node_handle.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. |
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* @headername{map,set,unordered_map,unordered_set} |
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*/ |
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|
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#ifndef _NODE_HANDLE |
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#define _NODE_HANDLE 1 |
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|
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#pragma GCC system_header |
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|
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#if __cplusplus >= 201703L |
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# define __cpp_lib_node_extract 201606 |
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|
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#include <new> |
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#include <bits/alloc_traits.h> |
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#include <bits/ptr_traits.h> |
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|
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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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|
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/// Base class for node handle types of maps and sets. |
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template<typename _Val, typename _NodeAlloc> |
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class _Node_handle_common |
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{ |
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using _AllocTraits = allocator_traits<_NodeAlloc>; |
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|
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public: |
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using allocator_type = __alloc_rebind<_NodeAlloc, _Val>; |
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|
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allocator_type |
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get_allocator() const noexcept |
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{ |
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__glibcxx_assert(!this->empty()); |
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return allocator_type(_M_alloc._M_alloc); |
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} |
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|
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explicit operator bool() const noexcept { return _M_ptr != nullptr; } |
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|
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[[nodiscard]] bool empty() const noexcept { return _M_ptr == nullptr; } |
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|
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protected: |
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constexpr _Node_handle_common() noexcept : _M_ptr() { } |
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|
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~_Node_handle_common() |
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{ |
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if (!empty()) |
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_M_reset(); |
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} |
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|
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_Node_handle_common(_Node_handle_common&& __nh) noexcept |
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: _M_ptr(__nh._M_ptr) |
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{ |
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if (_M_ptr) |
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_M_move(std::move(__nh)); |
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} |
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|
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_Node_handle_common& |
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operator=(_Node_handle_common&& __nh) noexcept |
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{ |
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if (empty()) |
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{ |
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if (!__nh.empty()) |
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_M_move(std::move(__nh)); |
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} |
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else if (__nh.empty()) |
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_M_reset(); |
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else |
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{ |
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// Free the current node before replacing the allocator. |
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_AllocTraits::destroy(*_M_alloc, _M_ptr->_M_valptr()); |
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_AllocTraits::deallocate(*_M_alloc, _M_ptr, 1); |
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|
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_M_alloc = __nh._M_alloc.release(); // assigns if POCMA |
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_M_ptr = __nh._M_ptr; |
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__nh._M_ptr = nullptr; |
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} |
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return *this; |
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} |
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|
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_Node_handle_common(typename _AllocTraits::pointer __ptr, |
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const _NodeAlloc& __alloc) |
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: _M_ptr(__ptr), _M_alloc(__alloc) |
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{ |
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__glibcxx_assert(__ptr != nullptr); |
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} |
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|
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void |
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_M_swap(_Node_handle_common& __nh) noexcept |
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{ |
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if (empty()) |
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{ |
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if (!__nh.empty()) |
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_M_move(std::move(__nh)); |
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} |
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else if (__nh.empty()) |
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__nh._M_move(std::move(*this)); |
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else |
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{ |
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using std::swap; |
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swap(_M_ptr, __nh._M_ptr); |
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_M_alloc.swap(__nh._M_alloc); // swaps if POCS |
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} |
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} |
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|
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private: |
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// Moves the pointer and allocator from __nh to *this. |
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// Precondition: empty() && !__nh.empty() |
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// Postcondition: !empty() && __nh.empty() |
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void |
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_M_move(_Node_handle_common&& __nh) noexcept |
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{ |
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::new (std::__addressof(_M_alloc)) _NodeAlloc(__nh._M_alloc.release()); |
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_M_ptr = __nh._M_ptr; |
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__nh._M_ptr = nullptr; |
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} |
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|
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// Deallocates the node, destroys the allocator. |
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// Precondition: !empty() |
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// Postcondition: empty() |
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void |
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_M_reset() noexcept |
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{ |
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_NodeAlloc __alloc = _M_alloc.release(); |
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_AllocTraits::destroy(__alloc, _M_ptr->_M_valptr()); |
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_AllocTraits::deallocate(__alloc, _M_ptr, 1); |
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_M_ptr = nullptr; |
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} |
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|
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protected: |
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typename _AllocTraits::pointer _M_ptr; |
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|
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private: |
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// A simplified, non-copyable std::optional<_NodeAlloc>. |
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// Call release() before destruction iff the allocator member is active. |
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union _Optional_alloc |
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{ |
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_Optional_alloc() { } |
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~_Optional_alloc() { } |
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|
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_Optional_alloc(_Optional_alloc&&) = delete; |
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_Optional_alloc& operator=(_Optional_alloc&&) = delete; |
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|
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_Optional_alloc(const _NodeAlloc& __alloc) noexcept |
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: _M_alloc(__alloc) |
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{ } |
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|
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// Precondition: _M_alloc is the active member of the union. |
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void |
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operator=(_NodeAlloc&& __alloc) noexcept |
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{ |
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using _ATr = _AllocTraits; |
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if constexpr (_ATr::propagate_on_container_move_assignment::value) |
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_M_alloc = std::move(__alloc); |
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else if constexpr (!_AllocTraits::is_always_equal::value) |
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__glibcxx_assert(_M_alloc == __alloc); |
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} |
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|
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// Precondition: _M_alloc is the active member of both unions. |
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void |
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swap(_Optional_alloc& __other) noexcept |
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{ |
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using std::swap; |
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if constexpr (_AllocTraits::propagate_on_container_swap::value) |
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swap(_M_alloc, __other._M_alloc); |
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else if constexpr (!_AllocTraits::is_always_equal::value) |
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__glibcxx_assert(_M_alloc == __other._M_alloc); |
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} |
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|
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// Precondition: _M_alloc is the active member of the union. |
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_NodeAlloc& operator*() noexcept { return _M_alloc; } |
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|
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// Precondition: _M_alloc is the active member of the union. |
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_NodeAlloc release() noexcept |
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{ |
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_NodeAlloc __tmp = std::move(_M_alloc); |
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_M_alloc.~_NodeAlloc(); |
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return __tmp; |
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} |
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|
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struct _Empty { }; |
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|
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[[__no_unique_address__]] _Empty _M_empty; |
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[[__no_unique_address__]] _NodeAlloc _M_alloc; |
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}; |
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|
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[[__no_unique_address__]] _Optional_alloc _M_alloc; |
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|
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template<typename _Key2, typename _Value2, typename _KeyOfValue, |
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typename _Compare, typename _ValueAlloc> |
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friend class _Rb_tree; |
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}; |
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|
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/// Node handle type for maps. |
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template<typename _Key, typename _Value, typename _NodeAlloc> |
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class _Node_handle : public _Node_handle_common<_Value, _NodeAlloc> |
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{ |
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public: |
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constexpr _Node_handle() noexcept = default; |
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~_Node_handle() = default; |
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_Node_handle(_Node_handle&&) noexcept = default; |
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|
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_Node_handle& |
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operator=(_Node_handle&&) noexcept = default; |
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|
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using key_type = _Key; |
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using mapped_type = typename _Value::second_type; |
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|
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key_type& |
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key() const noexcept |
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{ |
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__glibcxx_assert(!this->empty()); |
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return *_M_pkey; |
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} |
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|
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mapped_type& |
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mapped() const noexcept |
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{ |
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__glibcxx_assert(!this->empty()); |
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return *_M_pmapped; |
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} |
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|
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void |
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swap(_Node_handle& __nh) noexcept |
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{ |
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this->_M_swap(__nh); |
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using std::swap; |
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swap(_M_pkey, __nh._M_pkey); |
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swap(_M_pmapped, __nh._M_pmapped); |
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} |
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|
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friend void |
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swap(_Node_handle& __x, _Node_handle& __y) |
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noexcept(noexcept(__x.swap(__y))) |
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{ __x.swap(__y); } |
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|
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private: |
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using _AllocTraits = allocator_traits<_NodeAlloc>; |
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|
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_Node_handle(typename _AllocTraits::pointer __ptr, |
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const _NodeAlloc& __alloc) |
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: _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc) |
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{ |
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if (__ptr) |
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{ |
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auto& __key = const_cast<_Key&>(__ptr->_M_valptr()->first); |
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_M_pkey = _S_pointer_to(__key); |
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_M_pmapped = _S_pointer_to(__ptr->_M_valptr()->second); |
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} |
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else |
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{ |
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_M_pkey = nullptr; |
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_M_pmapped = nullptr; |
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} |
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} |
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|
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template<typename _Tp> |
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using __pointer |
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= __ptr_rebind<typename _AllocTraits::pointer, |
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remove_reference_t<_Tp>>; |
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|
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__pointer<_Key> _M_pkey = nullptr; |
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__pointer<typename _Value::second_type> _M_pmapped = nullptr; |
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|
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template<typename _Tp> |
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__pointer<_Tp> |
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_S_pointer_to(_Tp& __obj) |
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{ return pointer_traits<__pointer<_Tp>>::pointer_to(__obj); } |
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|
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const key_type& |
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_M_key() const noexcept { return key(); } |
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|
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template<typename _Key2, typename _Value2, typename _KeyOfValue, |
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typename _Compare, typename _ValueAlloc> |
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friend class _Rb_tree; |
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|
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template<typename _Key2, typename _Value2, typename _ValueAlloc, |
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typename _ExtractKey, typename _Equal, |
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typename _Hash, typename _RangeHash, typename _Unused, |
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typename _RehashPolicy, typename _Traits> |
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friend class _Hashtable; |
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}; |
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|
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/// Node handle type for sets. |
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template<typename _Value, typename _NodeAlloc> |
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class _Node_handle<_Value, _Value, _NodeAlloc> |
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: public _Node_handle_common<_Value, _NodeAlloc> |
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{ |
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public: |
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constexpr _Node_handle() noexcept = default; |
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~_Node_handle() = default; |
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_Node_handle(_Node_handle&&) noexcept = default; |
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|
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_Node_handle& |
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operator=(_Node_handle&&) noexcept = default; |
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|
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using value_type = _Value; |
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|
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value_type& |
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value() const noexcept |
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{ |
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__glibcxx_assert(!this->empty()); |
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return *this->_M_ptr->_M_valptr(); |
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} |
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|
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void |
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swap(_Node_handle& __nh) noexcept |
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{ this->_M_swap(__nh); } |
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|
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friend void |
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swap(_Node_handle& __x, _Node_handle& __y) |
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noexcept(noexcept(__x.swap(__y))) |
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{ __x.swap(__y); } |
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|
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private: |
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using _AllocTraits = allocator_traits<_NodeAlloc>; |
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|
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_Node_handle(typename _AllocTraits::pointer __ptr, |
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const _NodeAlloc& __alloc) |
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: _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc) { } |
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|
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const value_type& |
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_M_key() const noexcept { return value(); } |
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|
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template<typename _Key, typename _Val, typename _KeyOfValue, |
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typename _Compare, typename _Alloc> |
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friend class _Rb_tree; |
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|
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template<typename _Key2, typename _Value2, typename _ValueAlloc, |
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typename _ExtractKey, typename _Equal, |
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typename _Hash, typename _RangeHash, typename _Unused, |
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typename _RehashPolicy, typename _Traits> |
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friend class _Hashtable; |
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}; |
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|
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/// Return type of insert(node_handle&&) on unique maps/sets. |
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template<typename _Iterator, typename _NodeHandle> |
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struct _Node_insert_return |
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{ |
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_Iterator position = _Iterator(); |
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bool inserted = false; |
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_NodeHandle node; |
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}; |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace std |
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|
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#endif // C++17 |
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#endif |
