libstdc++-v3/include/bits/node_handle.h - gcc - Git at Google

 // Node handles for containers -*- C++ -*-

 // Copyright (C) 2016-2021 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 201606

 #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
	// Node handles for containers -- C++ --

	// Copyright (C) 2016-2021 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 201606

	#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