2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
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31 #ifndef CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H
32 #define CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H
34 #include <cds/intrusive/details/michael_list_base.h>
35 #include <cds/details/make_const_type.h>
37 namespace cds { namespace intrusive {
39 /// Michael's lock-free ordered single-linked list
40 /** @ingroup cds_intrusive_list
41 \anchor cds_intrusive_MichaelList_hp
43 Usually, ordered single-linked list is used as a building block for the hash table implementation.
44 The complexity of searching is <tt>O(N)</tt>.
47 - [2002] Maged Michael "High performance dynamic lock-free hash tables and list-based sets"
50 - \p GC - Garbage collector used. Note the \p GC must be the same as the GC used for item type \p T (see \p michael_list::node).
51 - \p T - type to be stored in the list. The type must be based on \p michael_list::node (for \p michael_list::base_hook)
52 or it must have a member of type \p michael_list::node (for \p michael_list::member_hook).
53 - \p Traits - type traits, default is \p michael_list::traits. It is possible to declare option-based
54 list with \p cds::intrusive::michael_list::make_traits metafunction:
55 For example, the following traits-based declaration of \p gc::HP Michael's list
57 #include <cds/intrusive/michael_list_hp.h>
58 // Declare item stored in your list
59 struct item: public cds::intrusive::michael_list::node< cds::gc::HP >
65 // Declare comparator for the item
67 int operator()( item const& i1, item const& i2 ) const
69 return i1.nKey - i2.nKey;
74 struct my_traits: public cds::intrusive::michael_list::traits
76 typedef cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
77 typedef my_compare compare;
80 // Declare traits-based list
81 typedef cds::intrusive::MichaelList< cds::gc::HP, item, my_traits > traits_based_list;
83 is equivalent for the following option-based list
85 #include <cds/intrusive/michael_list_hp.h>
87 // item struct and my_compare are the same
89 // Declare option-based list
90 typedef cds::intrusive::MichaelList< cds::gc::HP, item,
91 typename cds::intrusive::michael_list::make_traits<
92 cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP > > > // hook option
93 ,cds::intrusive::opt::compare< my_compare > // item comparator option
99 There are different specializations of this template for each garbage collecting schema.
100 You should select GC needed and include appropriate .h-file:
101 - for \p gc::HP: <tt> <cds/intrusive/michael_list_hp.h> </tt>
102 - for \p gc::DHP: <tt> <cds/intrusive/michael_list_dhp.h> </tt>
103 - for \ref cds_urcu_gc "RCU type" - see \ref cds_intrusive_MichaelList_rcu "RCU-based MichaelList"
104 - for \p gc::nogc: <tt> <cds/intrusive/michael_list_nogc.h> </tt>
105 See \ref cds_intrusive_MichaelList_nogc "non-GC MichaelList"
107 Then, you should incorporate \p michael_list::node into your struct \p T and provide
108 appropriate \p michael_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits you
109 define a struct based on \p michael_list::traits.
111 Example for \p gc::DHP and base hook:
113 // Include GC-related Michael's list specialization
114 #include <cds/intrusive/michael_list_dhp.h>
116 // Data stored in Michael's list
117 struct my_data: public cds::intrusive::michael_list::node< cds::gc::DHP >
126 // my_data comparing functor
128 int operator()( const my_data& d1, const my_data& d2 )
130 return d1.strKey.compare( d2.strKey );
133 int operator()( const my_data& d, const std::string& s )
135 return d.strKey.compare(s);
138 int operator()( const std::string& s, const my_data& d )
140 return s.compare( d.strKey );
146 struct my_traits: public cds::intrusive::michael_list::traits
148 typedef cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::DHP > > hook;
149 typedef my_data_cmp compare;
153 typedef cds::intrusive::MichaelList< cds::gc::DHP, my_data, my_traits > traits_based_list;
156 Equivalent option-based code:
158 // GC-related specialization
159 #include <cds/intrusive/michael_list_dhp.h>
168 // Declare option-based list
169 typedef cds::intrusive::MichaelList< cds::gc::DHP
171 , typename cds::intrusive::michael_list::make_traits<
172 cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::DHP > > >
173 ,cds::intrusive::opt::compare< my_data_cmp >
182 #ifdef CDS_DOXYGEN_INVOKED
183 ,class Traits = michael_list::traits
191 typedef T value_type; ///< type of value stored in the list
192 typedef Traits traits; ///< Traits template parameter
194 typedef typename traits::hook hook; ///< hook type
195 typedef typename hook::node_type node_type; ///< node type
197 # ifdef CDS_DOXYGEN_INVOKED
198 typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
200 typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
203 typedef typename traits::disposer disposer; ///< disposer used
204 typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
205 typedef typename michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
207 typedef GC gc ; ///< Garbage collector
208 typedef typename traits::back_off back_off; ///< back-off strategy
209 typedef typename traits::item_counter item_counter; ///< Item counting policy used
210 typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
212 typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
214 static CDS_CONSTEXPR const size_t c_nHazardPtrCount = 4; ///< Count of hazard pointer required for the algorithm
217 // Rebind traits (split-list support)
218 template <typename... Options>
219 struct rebind_traits {
223 , typename cds::opt::make_options< traits, Options...>::type
229 typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic node pointer
230 typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
232 typedef atomic_node_ptr auxiliary_head; ///< Auxiliary head type (for split-list support)
234 atomic_node_ptr m_pHead; ///< Head pointer
235 item_counter m_ItemCounter; ///< Item counter
238 /// Position pointer for item search
240 atomic_node_ptr * pPrev ; ///< Previous node
241 node_type * pCur ; ///< Current node
242 node_type * pNext ; ///< Next node
244 typename gc::template GuardArray<3> guards ; ///< Guards array
253 struct clean_disposer {
254 void operator()( value_type * p )
256 michael_list::node_cleaner<gc, node_type, memory_model>()( node_traits::to_node_ptr( p ));
264 static void retire_node( node_type * pNode )
266 assert( pNode != nullptr );
267 gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ));
270 static bool link_node( node_type * pNode, position& pos )
272 assert( pNode != nullptr );
273 link_checker::is_empty( pNode );
275 marked_node_ptr cur(pos.pCur);
276 pNode->m_pNext.store( cur, memory_model::memory_order_release );
277 return pos.pPrev->compare_exchange_strong( cur, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed );
280 static bool unlink_node( position& pos )
282 assert( pos.pPrev != nullptr );
283 assert( pos.pCur != nullptr );
285 // Mark the node (logical deleting)
286 marked_node_ptr next(pos.pNext, 0);
287 if ( pos.pCur->m_pNext.compare_exchange_strong( next, marked_node_ptr(pos.pNext, 1), memory_model::memory_order_release, atomics::memory_order_relaxed )) {
288 // physical deletion may be performed by search function if it detects that a node is logically deleted (marked)
289 // CAS may be successful here or in other thread that searching something
290 marked_node_ptr cur(pos.pCur);
291 if ( pos.pPrev->compare_exchange_strong( cur, marked_node_ptr( pos.pNext ), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
292 retire_node( pos.pCur );
301 template <bool IsConst>
304 friend class MichaelList;
307 value_type * m_pNode;
308 typename gc::Guard m_Guard;
313 typename gc::Guard g;
314 node_type * pCur = node_traits::to_node_ptr( *m_pNode );
316 marked_node_ptr pNext;
318 pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed);
319 g.assign( node_traits::to_value_ptr( pNext.ptr()));
320 } while ( pNext != pCur->m_pNext.load(memory_model::memory_order_acquire));
323 m_pNode = m_Guard.assign( g.template get<value_type>());
331 iterator_type( atomic_node_ptr const& pNode )
334 marked_node_ptr p = pNode.load(memory_model::memory_order_relaxed);
336 m_pNode = m_Guard.assign( node_traits::to_value_ptr( p.ptr()));
342 if ( p == pNode.load(memory_model::memory_order_acquire))
348 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
349 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
355 iterator_type( iterator_type const& src )
358 m_pNode = m_Guard.assign( src.m_pNode );
364 value_ptr operator ->() const
369 value_ref operator *() const
371 assert( m_pNode != nullptr );
376 iterator_type& operator ++()
382 iterator_type& operator = (iterator_type const& src)
384 m_pNode = src.m_pNode;
385 m_Guard.assign( m_pNode );
391 void operator ++(int)
398 bool operator ==(iterator_type<C> const& i ) const
400 return m_pNode == i.m_pNode;
403 bool operator !=(iterator_type<C> const& i ) const
405 return m_pNode != i.m_pNode;
411 ///@name Forward iterators (only for debugging purpose)
415 The forward iterator for Michael's list has some features:
416 - it has no post-increment operator
417 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
418 For some GC (like as \p gc::HP), a guard is a limited resource per thread, so an exception (or assertion) "no free guard"
419 may be thrown if the limit of guard count per thread is exceeded.
420 - The iterator cannot be moved across thread boundary since it contains thread-private GC's guard.
421 - Iterator ensures thread-safety even if you delete the item the iterator points to. However, in case of concurrent
422 deleting operations there is no guarantee that you iterate all item in the list.
423 Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
425 @warning Use this iterator on the concurrent container for debugging purpose only.
427 The iterator interface:
431 // Default constructor
435 iterator( iterator const& src );
437 // Dereference operator
438 value_type * operator ->() const;
440 // Dereference operator
441 value_type& operator *() const;
443 // Preincrement operator
444 iterator& operator ++();
446 // Assignment operator
447 iterator& operator = (iterator const& src);
449 // Equality operators
450 bool operator ==(iterator const& i ) const;
451 bool operator !=(iterator const& i ) const;
455 typedef iterator_type<false> iterator;
456 /// Const forward iterator
458 For iterator's features and requirements see \ref iterator
460 typedef iterator_type<true> const_iterator;
462 /// Returns a forward iterator addressing the first element in a list
464 For empty list \code begin() == end() \endcode
468 return iterator( m_pHead );
471 /// Returns an iterator that addresses the location succeeding the last element in a list
473 Do not use the value returned by <tt>end</tt> function to access any item.
474 Internally, <tt>end</tt> returning value equals to \p nullptr.
476 The returned value can be used only to control reaching the end of the list.
477 For empty list <tt>begin() == end()</tt>
484 /// Returns a forward const iterator addressing the first element in a list
485 const_iterator cbegin() const
487 return const_iterator( m_pHead );
490 /// Returns a forward const iterator addressing the first element in a list
491 const_iterator begin() const
493 return const_iterator( m_pHead );
496 /// Returns an const iterator that addresses the location succeeding the last element in a list
497 const_iterator end() const
499 return const_iterator();
502 /// Returns an const iterator that addresses the location succeeding the last element in a list
503 const_iterator cend() const
505 return const_iterator();
510 /// Default constructor initializes empty list
514 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
517 /// Destroys the list object
525 The function inserts \p val into the list if the list does not contain
526 an item with key equal to \p val.
528 Returns \p true if \p val has been linked to the list, \p false otherwise.
530 bool insert( value_type& val )
532 return insert_at( m_pHead, val );
537 This function is intended for derived non-intrusive containers.
539 The function allows to split new item creating into two part:
540 - create item with key only
541 - insert new item into the list
542 - if inserting is success, calls \p f functor to initialize value-field of \p val.
544 The functor signature is:
546 void func( value_type& val );
548 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
549 \p val no any other changes could be made on this list's item by concurrent threads.
550 The user-defined functor is called only if the inserting is success.
552 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
554 template <typename Func>
555 bool insert( value_type& val, Func f )
557 return insert_at( m_pHead, val, f );
562 The operation performs inserting or changing data with lock-free manner.
564 If the item \p val is not found in the list, then \p val is inserted
565 iff \p bInsert is \p true.
566 Otherwise, the functor \p func is called with item found.
567 The functor signature is:
569 void func( bool bNew, value_type& item, value_type& val );
572 - \p bNew - \p true if the item has been inserted, \p false otherwise
573 - \p item - item of the list
574 - \p val - argument \p val passed into the \p update() function
575 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
576 refers to the same thing.
578 The functor may change non-key fields of the \p item; however, \p func must guarantee
579 that during changing no any other modifications could be made on this item by concurrent threads.
581 Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
582 \p second is \p true if new item has been added or \p false if the item with \p key
583 already is in the list.
585 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
587 template <typename Func>
588 std::pair<bool, bool> update( value_type& val, Func func, bool bInsert = true )
590 return update_at( m_pHead, val, func, bInsert );
594 template <typename Func>
595 CDS_DEPRECATED("ensure() is deprecated, use update()")
596 std::pair<bool, bool> ensure( value_type& val, Func func )
598 return update( val, func, true );
602 /// Unlinks the item \p val from the list
604 The function searches the item \p val in the list and unlinks it from the list
605 if it is found and it is equal to \p val.
607 Difference between \p erase() and \p %unlink(): \p %erase() finds <i>a key</i>
608 and deletes the item found. \p %unlink() finds an item by key and deletes it
609 only if \p val is an item of the list, i.e. the pointer to item found
610 is equal to <tt> &val </tt>.
612 \p disposer specified in \p Traits is called for deleted item.
614 The function returns \p true if success and \p false otherwise.
616 bool unlink( value_type& val )
618 return unlink_at( m_pHead, val );
621 /// Deletes the item from the list
622 /** \anchor cds_intrusive_MichaelList_hp_erase_val
623 The function searches an item with key equal to \p key in the list,
624 unlinks it from the list, and returns \p true.
625 If \p key is not found the function return \p false.
627 \p disposer specified in \p Traits is called for deleted item.
629 template <typename Q>
630 bool erase( Q const& key )
632 return erase_at( m_pHead, key, key_comparator());
635 /// Deletes the item from the list using \p pred predicate for searching
637 The function is an analog of \ref cds_intrusive_MichaelList_hp_erase_val "erase(Q const&)"
638 but \p pred is used for key comparing.
639 \p Less functor has the interface like \p std::less.
640 \p pred must imply the same element order as the comparator used for building the list.
642 \p disposer specified in \p Traits is called for deleted item.
644 template <typename Q, typename Less>
645 bool erase_with( Q const& key, Less pred )
648 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
651 /// Deletes the item from the list
652 /** \anchor cds_intrusive_MichaelList_hp_erase_func
653 The function searches an item with key equal to \p key in the list,
654 call \p func functor with item found, unlinks it from the list, and returns \p true.
655 The \p Func interface is
658 void operator()( value_type const& item );
661 If \p key is not found the function return \p false, \p func is not called.
663 \p disposer specified in \p Traits is called for deleted item.
665 template <typename Q, typename Func>
666 bool erase( Q const& key, Func func )
668 return erase_at( m_pHead, key, key_comparator(), func );
671 /// Deletes the item from the list using \p pred predicate for searching
673 The function is an analog of \ref cds_intrusive_MichaelList_hp_erase_func "erase(Q const&, Func)"
674 but \p pred is used for key comparing.
675 \p Less functor has the interface like \p std::less.
676 \p pred must imply the same element order as the comparator used for building the list.
678 \p disposer specified in \p Traits is called for deleted item.
680 template <typename Q, typename Less, typename Func>
681 bool erase_with( Q const& key, Less pred, Func f )
684 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
687 /// Extracts the item from the list with specified \p key
688 /** \anchor cds_intrusive_MichaelList_hp_extract
689 The function searches an item with key equal to \p key,
690 unlinks it from the list, and returns it as \p guarded_ptr.
691 If \p key is not found returns an empty guarded pointer.
693 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
695 The \ref disposer specified in \p Traits class template parameter is called automatically
696 by garbage collector \p GC when returned \ref guarded_ptr object will be destroyed or released.
697 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
701 typedef cds::intrusive::MichaelList< cds::gc::HP, foo, my_traits > ord_list;
705 ord_list::guarded_ptr gp(theList.extract( 5 ));
710 // Destructor of gp releases internal HP guard
714 template <typename Q>
715 guarded_ptr extract( Q const& key )
718 extract_at( m_pHead, gp.guard(), key, key_comparator());
722 /// Extracts the item using compare functor \p pred
724 The function is an analog of \ref cds_intrusive_MichaelList_hp_extract "extract(Q const&)"
725 but \p pred predicate is used for key comparing.
727 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
729 \p pred must imply the same element order as the comparator used for building the list.
731 template <typename Q, typename Less>
732 guarded_ptr extract_with( Q const& key, Less pred )
736 extract_at( m_pHead, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
740 /// Finds \p key in the list
741 /** \anchor cds_intrusive_MichaelList_hp_find_func
742 The function searches the item with key equal to \p key and calls the functor \p f for item found.
743 The interface of \p Func functor is:
746 void operator()( value_type& item, Q& key );
749 where \p item is the item found, \p key is the <tt>find</tt> function argument.
751 The functor may change non-key fields of \p item. Note that the function is only guarantee
752 that \p item cannot be disposed during functor is executing.
753 The function does not serialize simultaneous access to the \p item. If such access is
754 possible you must provide your own synchronization schema to keep out unsafe item modifications.
756 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
757 may modify both arguments.
759 The function returns \p true if \p val is found, \p false otherwise.
761 template <typename Q, typename Func>
762 bool find( Q& key, Func f )
764 return find_at( m_pHead, key, key_comparator(), f );
767 template <typename Q, typename Func>
768 bool find( Q const& key, Func f )
770 return find_at( m_pHead, key, key_comparator(), f );
774 /// Finds the \p key using \p pred predicate for searching
776 The function is an analog of \ref cds_intrusive_MichaelList_hp_find_func "find(Q&, Func)"
777 but \p pred is used for key comparing.
778 \p Less functor has the interface like \p std::less.
779 \p pred must imply the same element order as the comparator used for building the list.
781 template <typename Q, typename Less, typename Func>
782 bool find_with( Q& key, Less pred, Func f )
785 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
788 template <typename Q, typename Less, typename Func>
789 bool find_with( Q const& key, Less pred, Func f )
792 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
796 /// Checks whether the list contains \p key
798 The function searches the item with key equal to \p key
799 and returns \p true if it is found, and \p false otherwise.
801 template <typename Q>
802 bool contains( Q const& key )
804 return find_at( m_pHead, key, key_comparator());
807 template <typename Q>
808 CDS_DEPRECATED("deprecated, use contains()")
809 bool find( Q const& key )
811 return contains( key );
815 /// Checks whether the list contains \p key using \p pred predicate for searching
817 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
818 \p Less functor has the interface like \p std::less.
819 \p Less must imply the same element order as the comparator used for building the list.
821 template <typename Q, typename Less>
822 bool contains( Q const& key, Less pred )
825 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
828 template <typename Q, typename Less>
829 CDS_DEPRECATED("deprecated, use contains()")
830 bool find_with( Q const& key, Less pred )
832 return contains( key, pred );
836 /// Finds the \p key and return the item found
837 /** \anchor cds_intrusive_MichaelList_hp_get
838 The function searches the item with key equal to \p key
839 and returns it as \p guarded_ptr.
840 If \p key is not found the function returns an empty guarded pointer.
842 The \ref disposer specified in \p Traits class template parameter is called
843 by garbage collector \p GC automatically when returned \ref guarded_ptr object
844 will be destroyed or released.
845 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
849 typedef cds::intrusive::MichaelList< cds::gc::HP, foo, my_traits > ord_list;
853 ord_list::guarded_ptr gp(theList.get( 5 ));
858 // Destructor of guarded_ptr releases internal HP guard
862 Note the compare functor specified for \p Traits template parameter
863 should accept a parameter of type \p Q that can be not the same as \p value_type.
865 template <typename Q>
866 guarded_ptr get( Q const& key )
869 get_at( m_pHead, gp.guard(), key, key_comparator());
873 /// Finds the \p key and return the item found
875 The function is an analog of \ref cds_intrusive_MichaelList_hp_get "get( Q const&)"
876 but \p pred is used for comparing the keys.
878 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
880 \p pred must imply the same element order as the comparator used for building the list.
882 template <typename Q, typename Less>
883 guarded_ptr get_with( Q const& key, Less pred )
887 get_at( m_pHead, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
893 The function unlink all items from the list.
897 typename gc::Guard guard;
898 marked_node_ptr head;
900 head = m_pHead.load(memory_model::memory_order_relaxed);
902 guard.assign( node_traits::to_value_ptr( *head.ptr()));
903 if ( m_pHead.load(memory_model::memory_order_acquire) == head ) {
904 if ( head.ptr() == nullptr )
906 value_type& val = *node_traits::to_value_ptr( *head.ptr());
912 /// Checks whether the list is empty
915 return m_pHead.load( memory_model::memory_order_relaxed ).all() == nullptr;
918 /// Returns list's item count
920 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
921 this function always returns 0.
923 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
924 is empty. To check list emptyness use \p empty() method.
928 return m_ItemCounter.value();
933 // split-list support
934 bool insert_aux_node( node_type * pNode )
936 return insert_aux_node( m_pHead, pNode );
939 // split-list support
940 bool insert_aux_node( atomic_node_ptr& refHead, node_type * pNode )
942 assert( pNode != nullptr );
944 // Hack: convert node_type to value_type.
945 // In principle, auxiliary node can be non-reducible to value_type
946 // We assume that comparator can correctly distinguish aux and regular node.
947 return insert_at( refHead, *node_traits::to_value_ptr( pNode ));
950 bool insert_at( atomic_node_ptr& refHead, value_type& val )
952 node_type * pNode = node_traits::to_node_ptr( val );
956 if ( search( refHead, val, pos, key_comparator()))
959 if ( link_node( pNode, pos )) {
965 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
969 template <typename Func>
970 bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
972 node_type * pNode = node_traits::to_node_ptr( val );
976 if ( search( refHead, val, pos, key_comparator()))
979 typename gc::Guard guard;
980 guard.assign( &val );
981 if ( link_node( pNode, pos )) {
988 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
992 template <typename Func>
993 std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
997 node_type * pNode = node_traits::to_node_ptr( val );
999 if ( search( refHead, val, pos, key_comparator())) {
1000 if ( pos.pCur->m_pNext.load(memory_model::memory_order_acquire).bits()) {
1002 continue; // the node found is marked as deleted
1004 assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur )) == 0 );
1006 func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
1007 return std::make_pair( true, false );
1011 return std::make_pair( false, false );
1013 typename gc::Guard guard;
1014 guard.assign( &val );
1015 if ( link_node( pNode, pos )) {
1017 func( true, val, val );
1018 return std::make_pair( true, true );
1021 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
1026 bool unlink_at( atomic_node_ptr& refHead, value_type& val )
1031 while ( search( refHead, val, pos, key_comparator())) {
1032 if ( node_traits::to_value_ptr( *pos.pCur ) == &val ) {
1033 if ( unlink_node( pos )) {
1046 template <typename Q, typename Compare, typename Func>
1047 bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp, Func f, position& pos )
1050 while ( search( refHead, val, pos, cmp )) {
1051 if ( unlink_node( pos )) {
1052 f( *node_traits::to_value_ptr( *pos.pCur ));
1062 template <typename Q, typename Compare, typename Func>
1063 bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp, Func f )
1066 return erase_at( refHead, val, cmp, f, pos );
1069 template <typename Q, typename Compare>
1070 bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1073 return erase_at( refHead, val, cmp, [](value_type const&){}, pos );
1076 template <typename Q, typename Compare>
1077 bool extract_at( atomic_node_ptr& refHead, typename guarded_ptr::native_guard& dest, Q const& val, Compare cmp )
1081 while ( search( refHead, val, pos, cmp )) {
1082 if ( unlink_node( pos )) {
1083 dest.set( pos.guards.template get<value_type>( position::guard_current_item ));
1093 template <typename Q, typename Compare>
1094 bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1097 return search( refHead, val, pos, cmp );
1100 template <typename Q, typename Compare, typename Func>
1101 bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f )
1104 if ( search( refHead, val, pos, cmp )) {
1105 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1111 template <typename Q, typename Compare>
1112 bool get_at( atomic_node_ptr& refHead, typename guarded_ptr::native_guard& guard, Q const& val, Compare cmp )
1115 if ( search( refHead, val, pos, cmp )) {
1116 guard.set( pos.guards.template get<value_type>( position::guard_current_item ));
1127 template <typename Q, typename Compare >
1128 bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp )
1130 atomic_node_ptr * pPrev;
1131 marked_node_ptr pNext;
1132 marked_node_ptr pCur;
1140 pCur = pos.guards.protect( position::guard_current_item, *pPrev,
1141 [](marked_node_ptr p) -> value_type *
1143 return node_traits::to_value_ptr( p.ptr());
1147 if ( pCur.ptr() == nullptr ) {
1150 pos.pNext = nullptr;
1154 pNext = pos.guards.protect( position::guard_next_item, pCur->m_pNext,
1155 [](marked_node_ptr p ) -> value_type *
1157 return node_traits::to_value_ptr( p.ptr());
1159 if ( pPrev->load(memory_model::memory_order_acquire).all() != pCur.ptr()) {
1164 // pNext contains deletion mark for pCur
1165 if ( pNext.bits() == 1 ) {
1166 // pCur marked i.e. logically deleted. Help the erase/unlink function to unlink pCur node
1167 marked_node_ptr cur( pCur.ptr());
1168 if ( pPrev->compare_exchange_strong( cur, marked_node_ptr( pNext.ptr()), memory_model::memory_order_acquire, atomics::memory_order_relaxed )) {
1169 retire_node( pCur.ptr());
1177 assert( pCur.ptr() != nullptr );
1178 int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr()), val );
1181 pos.pCur = pCur.ptr();
1182 pos.pNext = pNext.ptr();
1185 pPrev = &( pCur->m_pNext );
1186 pos.guards.copy( position::guard_prev_item, position::guard_current_item );
1189 pos.guards.copy( position::guard_current_item, position::guard_next_item );
1194 }} // namespace cds::intrusive
1196 #endif // #ifndef CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H