3 #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H
4 #define CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H
6 #include <type_traits> // is_base_of
7 #include <cds/container/details/bronson_avltree_base.h>
8 #include <cds/urcu/details/check_deadlock.h>
9 #include <cds/urcu/exempt_ptr.h>
11 namespace cds { namespace container {
13 /// Bronson et al AVL-tree (RCU specialization for storing pointer to values)
14 /** @ingroup cds_nonintrusive_map
15 @ingroup cds_nonintrusive_tree
16 @headerfile cds/container/bronson_avltree_map_rcu.h
17 @anchor cds_container_BronsonAVLTreeMap_rcu_ptr
19 This is the specialization of \ref cds_container_BronsonAVLTreeMap_rcu "RCU-based Bronson et al AVL-tree"
20 for "key -> value pointer" map. This specialization stores the pointer to user-allocated values instead of the copy
21 of the value. When a tree node is removed, the algorithm does not free the value pointer directly, instead, it call
22 the disposer functor provided by \p Traits template parameter.
24 <b>Template arguments</b>:
25 - \p RCU - one of \ref cds_urcu_gc "RCU type"
27 - \p T - value type to be stored in tree's nodes. Note, the specialization stores the pointer to user-allocated
29 - \p Traits - tree traits, default is \p bronson_avltree::traits
30 It is possible to declare option-based tree with \p bronson_avltree::make_traits metafunction
31 instead of \p Traits template argument.
33 @note Before including <tt><cds/container/bronson_avltree_map_rcu.h></tt> you should include appropriate RCU header file,
34 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
40 # ifdef CDS_DOXYGEN_INVOKED
41 typename Traits = bronson_avltree::traits
46 class BronsonAVLTreeMap< cds::urcu::gc<RCU>, Key, T*, Traits >
49 typedef cds::urcu::gc<RCU> gc; ///< RCU Garbage collector
50 typedef Key key_type; ///< type of a key stored in the map
51 typedef T * mapped_type; ///< type of value stored in the map
52 typedef Traits traits; ///< Traits template parameter
54 # ifdef CDS_DOXYGEN_INVOKED
55 typedef implementation_defined key_comparator; ///< key compare functor based on \p Traits::compare and \p Traits::less
57 typedef typename opt::details::make_comparator< key_type, traits >::type key_comparator;
59 typedef typename traits::item_counter item_counter; ///< Item counting policy
60 typedef typename traits::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model option
61 typedef typename traits::node_allocator node_allocator_type; ///< allocator for maintaining internal nodes
62 typedef typename traits::stat stat; ///< internal statistics
63 typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
64 typedef typename traits::back_off back_off; ///< Back-off strategy
65 typedef typename traits::disposer disposer; ///< Value disposer
66 typedef typename traits::sync_monitor sync_monitor; ///< @ref cds_sync_monitor "Synchronization monitor" type for node-level locking
68 /// Enabled or disabled @ref bronson_avltree::relaxed_insert "relaxed insertion"
69 static CDS_CONSTEXPR bool const c_bRelaxedInsert = traits::relaxed_insert;
71 /// Group of \p extract_xxx functions does not require external locking
72 static CDS_CONSTEXPR const bool c_bExtractLockExternal = false;
74 # ifdef CDS_DOXYGEN_INVOKED
75 /// Returned pointer to \p mapped_type of extracted node
76 typedef cds::urcu::exempt_ptr< gc, T, T, disposer, void > exempt_ptr;
78 typedef cds::urcu::exempt_ptr< gc,
79 typename std::remove_pointer<mapped_type>::type,
80 typename std::remove_pointer<mapped_type>::type,
86 typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
90 typedef bronson_avltree::node< key_type, mapped_type, sync_monitor > node_type;
91 typedef typename node_type::version_type version_type;
93 typedef cds::details::Allocator< node_type, node_allocator_type > cxx_allocator;
94 typedef cds::urcu::details::check_deadlock_policy< gc, rcu_check_deadlock > check_deadlock_policy;
96 enum class find_result
113 result_inserted = allow_insert,
114 result_updated = allow_update,
121 nothing_required = -3,
122 rebalance_required = -2,
131 typedef typename sync_monitor::template scoped_lock<node_type> node_scoped_lock;
136 template <typename K>
137 static node_type * alloc_node( K&& key, int nHeight, version_type version, node_type * pParent, node_type * pLeft, node_type * pRight )
139 return cxx_allocator().New( std::forward<K>( key ), nHeight, version, pParent, pLeft, pRight );
142 static void free_node( node_type * pNode )
144 // Free node without disposer
145 assert( !pNode->is_valued( memory_model::memory_order_relaxed ));
146 assert( pNode->m_SyncMonitorInjection.check_free());
147 cxx_allocator().Delete( pNode );
150 static void free_value( mapped_type pVal )
155 static node_type * child( node_type * pNode, int nDir, atomics::memory_order order = memory_model::memory_order_relaxed )
157 return pNode->child( nDir ).load( order );
160 static node_type * parent( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
162 return pNode->m_pParent.load( order );
168 node_type * m_pRetiredList; ///< head of retired node list
169 mapped_type m_pRetiredValue; ///< value retired
173 : m_pRetiredList( nullptr )
174 , m_pRetiredValue( nullptr )
182 void dispose( node_type * pNode )
184 assert( !pNode->is_valued( memory_model::memory_order_relaxed ));
185 pNode->m_pNextRemoved = m_pRetiredList;
186 m_pRetiredList = pNode;
189 void dispose_value( mapped_type pVal )
191 assert( m_pRetiredValue == nullptr );
192 m_pRetiredValue = pVal;
196 struct internal_disposer
198 void operator()( node_type * p ) const
206 assert( !gc::is_locked() );
208 // TODO: use RCU::batch_retire
211 for ( node_type * p = m_pRetiredList; p; ) {
212 node_type * pNext = static_cast<node_type *>( p->m_pNextRemoved );
213 // Value already disposed
214 gc::template retire_ptr<internal_disposer>( p );
219 if ( m_pRetiredValue )
220 gc::template retire_ptr<disposer>( m_pRetiredValue );
228 typename node_type::base_class m_Root;
230 item_counter m_ItemCounter;
231 mutable sync_monitor m_Monitor;
236 /// Creates empty map
238 : m_pRoot( static_cast<node_type *>( &m_Root ))
249 The \p key_type should be constructible from a value of type \p K.
251 RCU \p synchronize() can be called. RCU should not be locked.
253 Returns \p true if inserting successful, \p false otherwise.
255 template <typename K>
256 bool insert( K const& key, mapped_type pVal )
258 return do_update(key, key_comparator(),
259 [pVal]( node_type * pNode ) -> mapped_type
261 assert( pNode->m_pValue.load( memory_model::memory_order_relaxed ) == nullptr );
265 update_flags::allow_insert
266 ) == update_flags::result_inserted;
269 /// Updates the value for \p key
271 The operation performs inserting or updating the value for \p key with lock-free manner.
272 If \p bInsert is \p false, only updating of existing node is possible.
274 If \p key is not found and inserting is allowed (i.e. \p bInsert is \p true),
275 then the new node created from \p key will be inserted into the map; note that in this case the \ref key_type should be
276 constructible from type \p K.
277 Otherwise, the value for \p key will be changed to \p pVal.
279 RCU \p synchronize() method can be called. RCU should not be locked.
281 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
282 \p second is \p true if new node has been added or \p false if the node with \p key
285 template <typename K>
286 std::pair<bool, bool> update( K const& key, mapped_type pVal, bool bInsert = true )
288 int result = do_update( key, key_comparator(),
289 [pVal]( node_type * ) -> mapped_type
293 update_flags::allow_update | (bInsert ? update_flags::allow_insert : 0)
295 return std::make_pair( result != 0, (result & update_flags::result_inserted) != 0 );
299 template <typename K>
300 std::pair<bool, bool> ensure( K const& key, mapped_type pVal )
302 return update( key, pVal, true );
307 /// Delete \p key from the map
309 RCU \p synchronize() method can be called. RCU should not be locked.
311 Return \p true if \p key is found and deleted, \p false otherwise
313 template <typename K>
314 bool erase( K const& key )
319 []( key_type const&, mapped_type pVal, rcu_disposer& disp ) -> bool { disp.dispose_value( pVal ); return true; }
323 /// Deletes the item from the map using \p pred predicate for searching
325 The function is an analog of \p erase(K const&)
326 but \p pred is used for key comparing.
327 \p Less functor has the interface like \p std::less.
328 \p Less must imply the same element order as the comparator used for building the map.
330 template <typename K, typename Less>
331 bool erase_with( K const& key, Less pred )
336 cds::opt::details::make_comparator_from_less<Less>(),
337 []( key_type const&, mapped_type pVal, rcu_disposer& disp ) -> bool { disp.dispose_value( pVal ); return true; }
341 /// Delete \p key from the map
343 The function searches an item with key \p key, calls \p f functor
344 and deletes the item. If \p key is not found, the functor is not called.
346 The functor \p Func interface:
349 void operator()( key_type const& key, std::remove_pointer<mapped_type>::type& val) { ... }
353 RCU \p synchronize method can be called. RCU should not be locked.
355 Return \p true if key is found and deleted, \p false otherwise
357 template <typename K, typename Func>
358 bool erase( K const& key, Func f )
363 [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
366 disp.dispose_value(pVal);
372 /// Deletes the item from the map using \p pred predicate for searching
374 The function is an analog of \p erase(K const&, Func)
375 but \p pred is used for key comparing.
376 \p Less functor has the interface like \p std::less.
377 \p Less must imply the same element order as the comparator used for building the map.
379 template <typename K, typename Less, typename Func>
380 bool erase_with( K const& key, Less pred, Func f )
385 cds::opt::details::make_comparator_from_less<Less>(),
386 [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
389 disp.dispose_value(pVal);
395 /// Extracts a value with minimal key from the map
397 Returns \p exempt_ptr to the leftmost item.
398 If the tree is empty, returns empty \p exempt_ptr.
400 Note that the function returns only the value for minimal key.
401 To retrieve its key use \p extract_min( Func ) member function.
403 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
404 It means that the function gets leftmost leaf of the tree and tries to unlink it.
405 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
406 So, the function returns the item with minimum key at the moment of tree traversing.
408 RCU \p synchronize method can be called. RCU should NOT be locked.
409 The function does not free the item.
410 The deallocator will be implicitly invoked when the returned object is destroyed or when
411 its \p release() member function is called.
413 exempt_ptr extract_min()
415 return exempt_ptr(do_extract_min( []( key_type const& ) {}));
418 /// Extracts minimal key key and corresponding value
420 Returns \p exempt_ptr to the leftmost item.
421 If the tree is empty, returns empty \p exempt_ptr.
423 \p Func functor is used to store minimal key.
424 \p Func has the following signature:
427 void operator()( key_type const& key );
430 If the tree is empty, \p f is not called.
431 Otherwise, is it called with minimal key, the pointer to corresponding value is returned
434 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
435 It means that the function gets leftmost leaf of the tree and tries to unlink it.
436 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
437 So, the function returns the item with minimum key at the moment of tree traversing.
439 RCU \p synchronize method can be called. RCU should NOT be locked.
440 The function does not free the item.
441 The deallocator will be implicitly invoked when the returned object is destroyed or when
442 its \p release() member function is called.
444 template <typename Func>
445 exempt_ptr extract_min( Func f )
447 return exempt_ptr(do_extract_min( [&f]( key_type const& key ) { f(key); }));
450 /// Extracts minimal key key and corresponding value
452 This function is a shortcut for the following call:
455 exempt_ptr xp = theTree.extract_min( [&key]( key_type const& k ) { key = k; } );
457 \p key_type should be copy-assignable. The copy of minimal key
458 is returned in \p min_key argument.
460 typename std::enable_if< std::is_copy_assignable<key_type>::value, exempt_ptr >::type
461 extract_min_key( key_type& min_key )
463 return exempt_ptr(do_extract_min( [&min_key]( key_type const& key ) { min_key = key; }));
466 /// Extracts a value with maximal key from the tree
468 Returns \p exempt_ptr pointer to the rightmost item.
469 If the set is empty, returns empty \p exempt_ptr.
471 Note that the function returns only the value for maximal key.
472 To retrieve its key use \p extract_max( Func ) member function.
474 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
475 It means that the function gets rightmost leaf of the tree and tries to unlink it.
476 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
477 So, the function returns the item with maximum key at the moment of tree traversing.
479 RCU \p synchronize method can be called. RCU should NOT be locked.
480 The function does not free the item.
481 The deallocator will be implicitly invoked when the returned object is destroyed or when
482 its \p release() is called.
484 exempt_ptr extract_max()
486 return exempt_ptr(do_extract_max( []( key_type const& ) {}));
489 /// Extracts the maximal key and corresponding value
491 Returns \p exempt_ptr pointer to the rightmost item.
492 If the set is empty, returns empty \p exempt_ptr.
494 \p Func functor is used to store maximal key.
495 \p Func has the following signature:
498 void operator()( key_type const& key );
501 If the tree is empty, \p f is not called.
502 Otherwise, is it called with maximal key, the pointer to corresponding value is returned
505 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
506 It means that the function gets rightmost leaf of the tree and tries to unlink it.
507 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
508 So, the function returns the item with maximum key at the moment of tree traversing.
510 RCU \p synchronize method can be called. RCU should NOT be locked.
511 The function does not free the item.
512 The deallocator will be implicitly invoked when the returned object is destroyed or when
513 its \p release() is called.
515 template <typename Func>
516 exempt_ptr extract_max( Func f )
518 return exempt_ptr(do_extract_max( [&f]( key_type const& key ) { f(key); }));
521 /// Extracts the maximal key and corresponding value
523 This function is a shortcut for the following call:
526 exempt_ptr xp = theTree.extract_max( [&key]( key_type const& k ) { key = k; } );
528 \p key_type should be copy-assignable. The copy of maximal key
529 is returned in \p max_key argument.
531 typename std::enable_if< std::is_copy_assignable<key_type>::value, exempt_ptr >::type
532 extract_max_key( key_type& max_key )
534 return exempt_ptr(do_extract_max( [&max_key]( key_type const& key ) { max_key = key; }));
537 /// Extracts an item from the map
539 The function searches an item with key equal to \p key in the tree,
540 unlinks it, and returns \p exempt_ptr pointer to a value found.
541 If \p key is not found the function returns an empty \p exempt_ptr.
543 RCU \p synchronize method can be called. RCU should NOT be locked.
544 The function does not destroy the value found.
545 The disposer will be implicitly invoked when the returned object is destroyed or when
546 its \p release() member function is called.
548 template <typename Q>
549 exempt_ptr extract( Q const& key )
551 return exempt_ptr(do_extract( key ));
555 /// Extracts an item from the map using \p pred for searching
557 The function is an analog of \p extract(Q const&)
558 but \p pred is used for key compare.
559 \p Less has the interface like \p std::less.
560 \p pred must imply the same element order as the comparator used for building the tree.
562 template <typename Q, typename Less>
563 exempt_ptr extract_with( Q const& key, Less pred )
565 return exempt_ptr(do_extract_with( key, pred ));
568 /// Find the key \p key
570 The function searches the item with key equal to \p key and calls the functor \p f for item found.
571 The interface of \p Func functor is:
574 void operator()( key_type const& key, mapped_type& item );
577 where \p item is the item found.
578 The functor is called under node-level lock.
580 The function applies RCU lock internally.
582 The function returns \p true if \p key is found, \p false otherwise.
584 template <typename K, typename Func>
585 bool find( K const& key, Func f )
587 return do_find( key, key_comparator(),
588 [&f]( node_type * pNode ) -> bool {
589 assert( pNode != nullptr );
590 mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
592 f( pNode->m_key, *pVal );
600 /// Finds the key \p val using \p pred predicate for searching
602 The function is an analog of \p find(K const&, Func)
603 but \p pred is used for key comparing.
604 \p Less functor has the interface like \p std::less.
605 \p Less must imply the same element order as the comparator used for building the map.
607 template <typename K, typename Less, typename Func>
608 bool find_with( K const& key, Less pred, Func f )
611 return do_find( key, cds::opt::details::make_comparator_from_less<Less>(),
612 [&f]( node_type * pNode ) -> bool {
613 assert( pNode != nullptr );
614 mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
616 f( pNode->m_key, *pVal );
624 /// Find the key \p key
626 The function searches the item with key equal to \p key
627 and returns \p true if it is found, and \p false otherwise.
629 The function applies RCU lock internally.
631 template <typename K>
632 bool find( K const& key )
634 return do_find( key, key_comparator(), []( node_type * ) -> bool { return true; });
637 /// Finds the key \p val using \p pred predicate for searching
639 The function is an analog of \p find(K const&)
640 but \p pred is used for key comparing.
641 \p Less functor has the interface like \p std::less.
642 \p Less must imply the same element order as the comparator used for building the map.
644 template <typename K, typename Less>
645 bool find_with( K const& key, Less pred )
648 return do_find( key, cds::opt::details::make_comparator_from_less<Less>(), []( node_type * ) -> bool { return true; } );
651 /// Clears the tree (thread safe, not atomic)
653 The function unlink all items from the tree.
654 The function is thread safe but not atomic: in multi-threaded environment with parallel insertions
658 assert( set.empty() );
660 the assertion could be raised.
662 For each node the \ref disposer will be called after unlinking.
664 RCU \p synchronize method can be called. RCU should not be locked.
668 while ( extract_min() );
671 /// Clears the tree (not thread safe)
673 This function is not thread safe and may be called only when no other thread deals with the tree.
674 The function is used in the tree destructor.
678 clear(); // temp solution
682 /// Checks if the map is empty
685 return m_Root.m_pRight.load( memory_model::memory_order_relaxed ) == nullptr;
688 /// Returns item count in the map
690 Only leaf nodes containing user data are counted.
692 The value returned depends on item counter type provided by \p Traits template parameter.
693 If it is \p atomicity::empty_item_counter this function always returns 0.
695 The function is not suitable for checking the tree emptiness, use \p empty()
696 member function for this purpose.
700 return m_ItemCounter;
703 /// Returns const reference to internal statistics
704 stat const& statistics() const
709 /// Returns reference to \p sync_monitor object
710 sync_monitor& monitor()
715 sync_monitor const& monitor() const
721 /// Checks internal consistency (not atomic, not thread-safe)
723 The debugging function to check internal consistency of the tree.
725 bool check_consistency() const
727 return check_consistency([]( size_t /*nLevel*/, size_t /*hLeft*/, size_t /*hRight*/ ){} );
730 /// Checks internal consistency (not atomic, not thread-safe)
732 The debugging function to check internal consistency of the tree.
733 The functor \p Func is called if a violation of internal tree structure
737 void operator()( size_t nLevel, size_t hLeft, size_t hRight );
741 - \p nLevel - the level where the violation is found
742 - \p hLeft - the height of left subtree
743 - \p hRight - the height of right subtree
745 The functor is called for each violation found.
747 template <typename Func>
748 bool check_consistency( Func f ) const
750 node_type * pChild = child( m_pRoot, right_child );
753 do_check_consistency( pChild, 1, f, nErrors );
761 template <typename Func>
762 size_t do_check_consistency( node_type * pNode, size_t nLevel, Func f, size_t& nErrors ) const
766 node_type * pLeft = child( pNode, left_child );
767 node_type * pRight = child( pNode, right_child );
768 if ( pLeft && cmp( pLeft->m_key, pNode->m_key ) > 0 )
770 if ( pRight && cmp( pNode->m_key, pRight->m_key ) > 0 )
773 size_t hLeft = do_check_consistency( pLeft, nLevel + 1, f, nErrors );
774 size_t hRight = do_check_consistency( pRight, nLevel + 1, f, nErrors );
776 if ( hLeft >= hRight ) {
777 if ( hLeft - hRight > 1 ) {
778 f( nLevel, hLeft, hRight );
784 if ( hRight - hLeft > 1 ) {
785 f( nLevel, hLeft, hRight );
794 template <typename Q, typename Compare, typename Func>
795 bool do_find( Q& key, Compare cmp, Func f ) const
800 result = try_find( key, cmp, f, m_pRoot, 1, 0 );
802 assert( result != find_result::retry );
803 return result == find_result::found;
806 template <typename K, typename Compare, typename Func>
807 int do_update( K const& key, Compare cmp, Func funcUpdate, int nFlags )
809 check_deadlock_policy::check();
811 rcu_disposer removed_list;
814 return try_update_root( key, cmp, nFlags, funcUpdate, removed_list );
818 template <typename K, typename Compare, typename Func>
819 bool do_remove( K const& key, Compare cmp, Func func )
821 // Func must return true if the value was disposed
822 // or false if the value was extracted
824 check_deadlock_policy::check();
826 rcu_disposer removed_list;
829 return try_remove_root( key, cmp, func, removed_list );
833 template <typename Func>
834 mapped_type do_extract_min( Func f )
836 mapped_type pExtracted = nullptr;
839 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
844 template <typename Func>
845 mapped_type do_extract_max( Func f )
847 mapped_type pExtracted = nullptr;
850 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
855 template <typename Func>
856 void do_extract_minmax( int nDir, Func func )
858 check_deadlock_policy::check();
860 rcu_disposer removed_list;
864 int result = update_flags::failed;
866 // get right child of root
867 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
869 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
870 if ( nChildVersion & node_type::shrinking ) {
871 m_stat.onRemoveRootWaitShrinking();
872 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
873 result = update_flags::retry;
875 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
876 result = try_extract_minmax( nDir, func, m_pRoot, pChild, nChildVersion, removed_list );
879 } while ( result == update_flags::retry );
883 template <typename Q>
884 mapped_type do_extract( Q const& key )
886 mapped_type pExtracted = nullptr;
890 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
895 template <typename Q, typename Less>
896 mapped_type do_extract_with( Q const& key, Less pred )
899 mapped_type pExtracted = nullptr;
902 cds::opt::details::make_comparator_from_less<Less>(),
903 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
911 static int height( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
914 return pNode->m_nHeight.load( order );
916 static void set_height( node_type * pNode, int h, atomics::memory_order order = memory_model::memory_order_relaxed )
919 pNode->m_nHeight.store( h, order );
921 static int height_null( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
923 return pNode ? height( pNode, order ) : 0;
926 template <typename Q, typename Compare, typename Func>
927 find_result try_find( Q const& key, Compare cmp, Func f, node_type * pNode, int nDir, version_type nVersion ) const
929 assert( gc::is_locked() );
933 node_type * pChild = child( pNode, nDir );
935 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
936 m_stat.onFindRetry();
937 return find_result::retry;
940 m_stat.onFindFailed();
941 return find_result::not_found;
944 int nCmp = cmp( key, pChild->m_key );
946 if ( pChild->is_valued( memory_model::memory_order_relaxed ) ) {
948 node_scoped_lock l( m_Monitor, *pChild );
949 if ( pChild->is_valued( memory_model::memory_order_relaxed )) {
951 m_stat.onFindSuccess();
952 return find_result::found;
957 m_stat.onFindFailed();
958 return find_result::not_found;
961 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
962 if ( nChildVersion & node_type::shrinking ) {
963 m_stat.onFindWaitShrinking();
964 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
966 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
967 m_stat.onFindRetry();
968 return find_result::retry;
971 else if ( nChildVersion != node_type::unlinked ) {
972 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
973 m_stat.onFindRetry();
974 return find_result::retry;
977 find_result found = try_find( key, cmp, f, pChild, nCmp, nChildVersion );
978 if ( found != find_result::retry ) {
979 if ( found == find_result::not_found && child(pNode, nDir) != pChild ) {
980 // Oops! That is a bug!!!
981 m_stat.onFindNotFoundRetry();
988 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
989 m_stat.onFindRetry();
990 return find_result::retry;
995 template <typename K, typename Compare, typename Func>
996 int try_update_root( K const& key, Compare cmp, int nFlags, Func funcUpdate, rcu_disposer& disp )
998 assert( gc::is_locked() );
1002 // get right child of root
1003 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
1005 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
1006 if ( nChildVersion & node_type::shrinking ) {
1007 m_stat.onUpdateRootWaitShrinking();
1008 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1009 result = update_flags::retry;
1011 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
1012 result = try_update( key, cmp, nFlags, funcUpdate, m_pRoot, pChild, nChildVersion, disp );
1015 result = update_flags::retry;
1018 // the tree is empty
1019 if ( nFlags & update_flags::allow_insert ) {
1020 // insert into tree as right child of the root
1022 node_scoped_lock l( m_Monitor, *m_pRoot );
1023 if ( child( m_pRoot, right_child, memory_model::memory_order_acquire ) != nullptr ) {
1024 result = update_flags::retry;
1028 node_type * pNew = alloc_node( key, 1, 0, m_pRoot, nullptr, nullptr );
1029 mapped_type pVal = funcUpdate( pNew );
1030 assert( pVal != nullptr );
1031 pNew->m_pValue.store( pVal, memory_model::memory_order_release );
1033 m_pRoot->child( pNew, right_child, memory_model::memory_order_relaxed );
1034 set_height( m_pRoot, 2 );
1038 m_stat.onInsertSuccess();
1039 return update_flags::result_inserted;
1042 return update_flags::failed;
1044 } while ( result == update_flags::retry );
1048 template <typename K, typename Compare, typename Func>
1049 bool try_remove_root( K const& key, Compare cmp, Func func, rcu_disposer& disp )
1051 assert( gc::is_locked() );
1055 // get right child of root
1056 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
1058 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
1059 if ( nChildVersion & node_type::shrinking ) {
1060 m_stat.onRemoveRootWaitShrinking();
1061 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1062 result = update_flags::retry;
1064 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
1065 result = try_remove( key, cmp, func, m_pRoot, pChild, nChildVersion, disp );
1068 result = update_flags::retry;
1072 } while ( result == update_flags::retry );
1074 return result == update_flags::result_removed;
1077 template <typename K, typename Compare, typename Func>
1078 int try_update( K const& key, Compare cmp, int nFlags, Func funcUpdate, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1080 assert( gc::is_locked() );
1081 assert( nVersion != node_type::unlinked );
1082 CDS_UNUSED( pParent );
1084 int nCmp = cmp( key, pNode->m_key );
1086 if ( nFlags & update_flags::allow_update ) {
1087 return try_update_node( funcUpdate, pNode, disp );
1089 return update_flags::failed;
1094 node_type * pChild = child( pNode, nCmp );
1095 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1096 m_stat.onUpdateRetry();
1097 return update_flags::retry;
1100 if ( pChild == nullptr ) {
1102 if ( nFlags & update_flags::allow_insert )
1103 result = try_insert_node( key, funcUpdate, pNode, nCmp, nVersion, disp );
1105 result = update_flags::failed;
1109 result = update_flags::retry;
1110 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1111 if ( nChildVersion & node_type::shrinking ) {
1112 m_stat.onUpdateWaitShrinking();
1113 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1116 else if ( pChild == child( pNode, nCmp )) {
1117 // this second read is important, because it is protected by nChildVersion
1119 // validate the read that our caller took to get to node
1120 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1121 m_stat.onUpdateRetry();
1122 return update_flags::retry;
1125 // At this point we know that the traversal our parent took to get to node is still valid.
1126 // The recursive implementation will validate the traversal from node to
1127 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1128 // This means that we are no longer vulnerable to node shrinks, and we don't need
1129 // to validate node version any more.
1130 result = try_update( key, cmp, nFlags, funcUpdate, pNode, pChild, nChildVersion, disp );
1134 if ( result == update_flags::retry && pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1135 m_stat.onUpdateRetry();
1136 return update_flags::retry;
1138 } while ( result == update_flags::retry );
1142 template <typename K, typename Compare, typename Func>
1143 int try_remove( K const& key, Compare cmp, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1145 assert( gc::is_locked() );
1146 assert( nVersion != node_type::unlinked );
1148 int nCmp = cmp( key, pNode->m_key );
1150 return try_remove_node( pParent, pNode, nVersion, func, disp );
1154 node_type * pChild = child( pNode, nCmp );
1155 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1156 m_stat.onRemoveRetry();
1157 return update_flags::retry;
1160 if ( pChild == nullptr ) {
1161 return update_flags::failed;
1165 result = update_flags::retry;
1166 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1167 if ( nChildVersion & node_type::shrinking ) {
1168 m_stat.onRemoveWaitShrinking();
1169 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1172 else if ( pChild == child( pNode, nCmp )) {
1173 // this second read is important, because it is protected by nChildVersion
1175 // validate the read that our caller took to get to node
1176 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1177 m_stat.onRemoveRetry();
1178 return update_flags::retry;
1181 // At this point we know that the traversal our parent took to get to node is still valid.
1182 // The recursive implementation will validate the traversal from node to
1183 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1184 // This means that we are no longer vulnerable to node shrinks, and we don't need
1185 // to validate node version any more.
1186 result = try_remove( key, cmp, func, pNode, pChild, nChildVersion, disp );
1190 if ( result == update_flags::retry && pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1191 m_stat.onRemoveRetry();
1192 return update_flags::retry;
1194 } while ( result == update_flags::retry );
1198 template <typename Func>
1199 int try_extract_minmax( int nDir, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1201 assert( gc::is_locked() );
1202 assert( nVersion != node_type::unlinked );
1206 node_type * pChild = child( pNode, nDir );
1207 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1208 m_stat.onRemoveRetry();
1209 return update_flags::retry;
1212 if ( pChild == nullptr ) {
1214 return try_remove_node( pParent, pNode, nVersion, func, disp );
1217 result = update_flags::retry;
1218 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1219 if ( nChildVersion & node_type::shrinking ) {
1220 m_stat.onRemoveWaitShrinking();
1221 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1224 else if ( pChild == child( pNode, nDir )) {
1225 // this second read is important, because it is protected by nChildVersion
1227 // validate the read that our caller took to get to node
1228 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1229 m_stat.onRemoveRetry();
1230 return update_flags::retry;
1233 // At this point we know that the traversal our parent took to get to node is still valid.
1234 // The recursive implementation will validate the traversal from node to
1235 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1236 // This means that we are no longer vulnerable to node shrinks, and we don't need
1237 // to validate node version any more.
1238 result = try_extract_minmax( nDir, func, pNode, pChild, nChildVersion, disp );
1242 if ( result == update_flags::retry && pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1243 m_stat.onRemoveRetry();
1244 return update_flags::retry;
1246 } while ( result == update_flags::retry );
1250 template <typename K, typename Func>
1251 int try_insert_node( K const& key, Func funcUpdate, node_type * pNode, int nDir, version_type nVersion, rcu_disposer& disp )
1255 auto fnCreateNode = [&funcUpdate]( node_type * pNew ) {
1256 mapped_type pVal = funcUpdate( pNew );
1257 assert( pVal != nullptr );
1258 pNew->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1261 if ( c_bRelaxedInsert ) {
1262 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1263 || child( pNode, nDir ) != nullptr )
1265 m_stat.onInsertRetry();
1266 return update_flags::retry;
1269 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1272 node_type * pDamaged;
1274 assert( pNode != nullptr );
1275 node_scoped_lock l( m_Monitor, *pNode );
1277 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion
1278 || child( pNode, nDir ) != nullptr )
1280 if ( c_bRelaxedInsert ) {
1281 mapped_type pVal = pNew->m_pValue.load( memory_model::memory_order_relaxed );
1282 pNew->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1285 m_stat.onRelaxedInsertFailed();
1288 m_stat.onInsertRetry();
1289 return update_flags::retry;
1292 if ( !c_bRelaxedInsert )
1293 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1295 pNode->child( pNew, nDir, memory_model::memory_order_relaxed );
1296 pDamaged = fix_height_locked( pNode );
1300 m_stat.onInsertSuccess();
1303 fix_height_and_rebalance( pDamaged, disp );
1304 m_stat.onInsertRebalanceRequired();
1307 return update_flags::result_inserted;
1310 template <typename Func>
1311 int try_update_node( Func funcUpdate, node_type * pNode, rcu_disposer& disp )
1314 assert( pNode != nullptr );
1316 node_scoped_lock l( m_Monitor, *pNode );
1318 if ( pNode->is_unlinked( memory_model::memory_order_relaxed )) {
1319 m_stat.onUpdateUnlinked();
1320 return update_flags::retry;
1323 pOld = pNode->value( memory_model::memory_order_relaxed );
1324 mapped_type pVal = funcUpdate( pNode );
1328 assert( pVal != nullptr );
1329 pNode->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1334 disp.dispose_value(pOld);
1335 m_stat.onDisposeValue();
1338 m_stat.onUpdateSuccess();
1339 return update_flags::result_updated;
1342 template <typename Func>
1343 int try_remove_node( node_type * pParent, node_type * pNode, version_type nVersion, Func func, rcu_disposer& disp )
1345 assert( pParent != nullptr );
1346 assert( pNode != nullptr );
1348 if ( !pNode->is_valued( atomics::memory_order_relaxed ) )
1349 return update_flags::failed;
1351 if ( child( pNode, left_child ) == nullptr || child( pNode, right_child ) == nullptr ) {
1352 node_type * pDamaged;
1355 node_scoped_lock lp( m_Monitor, *pParent );
1356 if ( pParent->is_unlinked( atomics::memory_order_relaxed ) || parent( pNode ) != pParent )
1357 return update_flags::retry;
1360 node_scoped_lock ln( m_Monitor, *pNode );
1361 pOld = pNode->value( memory_model::memory_order_relaxed );
1362 if ( !( pNode->version( memory_model::memory_order_relaxed ) == nVersion
1364 && try_unlink_locked( pParent, pNode, disp )))
1366 return update_flags::retry;
1369 pDamaged = fix_height_locked( pParent );
1373 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1374 m_stat.onDisposeValue();
1376 m_stat.onExtractValue();
1379 fix_height_and_rebalance( pDamaged, disp );
1380 m_stat.onRemoveRebalanceRequired();
1382 return update_flags::result_removed;
1385 int result = update_flags::retry;
1388 node_scoped_lock ln( m_Monitor, *pNode );
1389 pOld = pNode->value( atomics::memory_order_relaxed );
1390 if ( pNode->version( atomics::memory_order_relaxed ) == nVersion && pOld ) {
1391 pNode->m_pValue.store( nullptr, atomics::memory_order_relaxed );
1392 result = update_flags::result_removed;
1396 if ( result == update_flags::result_removed ) {
1398 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1399 m_stat.onDisposeValue();
1401 m_stat.onExtractValue();
1408 bool try_unlink_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1410 // pParent and pNode must be locked
1411 assert( !pParent->is_unlinked(memory_model::memory_order_relaxed) );
1413 node_type * pParentLeft = child( pParent, left_child );
1414 node_type * pParentRight = child( pParent, right_child );
1415 if ( pNode != pParentLeft && pNode != pParentRight ) {
1416 // node is no longer a child of parent
1420 assert( !pNode->is_unlinked( memory_model::memory_order_relaxed ) );
1421 assert( pParent == parent( pNode ));
1423 node_type * pLeft = child( pNode, left_child );
1424 node_type * pRight = child( pNode, right_child );
1425 if ( pLeft != nullptr && pRight != nullptr ) {
1426 // splicing is no longer possible
1429 node_type * pSplice = pLeft ? pLeft : pRight;
1431 if ( pParentLeft == pNode )
1432 pParent->m_pLeft.store( pSplice, memory_model::memory_order_relaxed );
1434 pParent->m_pRight.store( pSplice, memory_model::memory_order_relaxed );
1437 pSplice->m_pParent.store( pParent, memory_model::memory_order_release );
1439 // Mark the node as unlinked
1440 pNode->version( node_type::unlinked, memory_model::memory_order_release );
1442 // The value will be disposed by calling function
1443 pNode->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1445 disp.dispose( pNode );
1446 m_stat.onDisposeNode();
1453 private: // rotations
1455 int estimate_node_condition( node_type * pNode )
1457 node_type * pLeft = child( pNode, left_child );
1458 node_type * pRight = child( pNode, right_child );
1460 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1461 return unlink_required;
1463 int h = height( pNode );
1464 int hL = height_null( pLeft );
1465 int hR = height_null( pRight );
1467 int hNew = 1 + std::max( hL, hR );
1468 int nBalance = hL - hR;
1470 if ( nBalance < -1 || nBalance > 1 )
1471 return rebalance_required;
1473 return h != hNew ? hNew : nothing_required;
1476 node_type * fix_height( node_type * pNode )
1478 assert( pNode != nullptr );
1479 node_scoped_lock l( m_Monitor, *pNode );
1480 return fix_height_locked( pNode );
1483 node_type * fix_height_locked( node_type * pNode )
1485 // pNode must be locked!!!
1486 int h = estimate_node_condition( pNode );
1488 case rebalance_required:
1489 case unlink_required:
1491 case nothing_required:
1494 set_height( pNode, h );
1495 return parent( pNode );
1499 void fix_height_and_rebalance( node_type * pNode, rcu_disposer& disp )
1501 while ( pNode && parent( pNode )) {
1502 int nCond = estimate_node_condition( pNode );
1503 if ( nCond == nothing_required || pNode->is_unlinked( memory_model::memory_order_relaxed ) )
1506 if ( nCond != unlink_required && nCond != rebalance_required )
1507 pNode = fix_height( pNode );
1509 node_type * pParent = parent( pNode );
1510 assert( pParent != nullptr );
1512 node_scoped_lock lp( m_Monitor, *pParent );
1513 if ( !pParent->is_unlinked( memory_model::memory_order_relaxed ) && parent( pNode ) == pParent ) {
1514 node_scoped_lock ln( m_Monitor, *pNode );
1515 pNode = rebalance_locked( pParent, pNode, disp );
1522 node_type * rebalance_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1524 // pParent and pNode should be locked.
1525 // Returns a damaged node, or nullptr if no more rebalancing is necessary
1526 assert( parent( pNode ) == pParent );
1528 node_type * pLeft = child( pNode, left_child );
1529 node_type * pRight = child( pNode, right_child );
1531 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1532 if ( try_unlink_locked( pParent, pNode, disp ))
1533 return fix_height_locked( pParent );
1535 // retry needed for pNode
1540 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1542 int h = height( pNode );
1543 int hL = height_null( pLeft );
1544 int hR = height_null( pRight );
1545 int hNew = 1 + std::max( hL, hR );
1546 int balance = hL - hR;
1549 return rebalance_to_right_locked( pParent, pNode, pLeft, hR );
1550 else if ( balance < -1 )
1551 return rebalance_to_left_locked( pParent, pNode, pRight, hL );
1552 else if ( hNew != h ) {
1553 set_height( pNode, hNew );
1555 // pParent is already locked
1556 return fix_height_locked( pParent );
1562 node_type * rebalance_to_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR )
1564 assert( parent( pNode ) == pParent );
1565 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1567 // pParent and pNode is locked yet
1568 // pNode->pLeft is too large, we will rotate-right.
1569 // If pLeft->pRight is taller than pLeft->pLeft, then we will first rotate-left pLeft.
1572 assert( pLeft != nullptr );
1573 node_scoped_lock l( m_Monitor, *pLeft );
1574 if ( pNode->m_pLeft.load( memory_model::memory_order_relaxed ) != pLeft )
1575 return pNode; // retry for pNode
1577 int hL = height( pLeft );
1579 return pNode; // retry
1581 node_type * pLRight = child( pLeft, right_child );
1582 int hLR = height_null( pLRight );
1583 node_type * pLLeft = child( pLeft, left_child );
1584 int hLL = height_null( pLLeft );
1588 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1591 assert( pLRight != nullptr );
1593 node_scoped_lock lr( m_Monitor, *pLRight );
1594 if ( pLeft->m_pRight.load( memory_model::memory_order_relaxed ) != pLRight )
1595 return pNode; // retry
1597 hLR = height( pLRight );
1599 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1601 int hLRL = height_null( child( pLRight, left_child ));
1602 int balance = hLL - hLRL;
1603 if ( balance >= -1 && balance <= 1 && !((hLL == 0 || hLRL == 0) && !pLeft->is_valued(memory_model::memory_order_relaxed))) {
1604 // nParent.child.left won't be damaged after a double rotation
1605 return rotate_right_over_left_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLRL );
1609 // focus on pLeft, if necessary pNode will be balanced later
1610 return rebalance_to_left_locked( pNode, pLeft, pLRight, hLL );
1615 node_type * rebalance_to_left_locked( node_type * pParent, node_type * pNode, node_type * pRight, int hL )
1617 assert( parent( pNode ) == pParent );
1618 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1620 // pParent and pNode is locked yet
1622 assert( pRight != nullptr );
1623 node_scoped_lock l( m_Monitor, *pRight );
1624 if ( pNode->m_pRight.load( memory_model::memory_order_relaxed ) != pRight )
1625 return pNode; // retry for pNode
1627 int hR = height( pRight );
1628 if ( hL - hR >= -1 )
1629 return pNode; // retry
1631 node_type * pRLeft = child( pRight, left_child );
1632 int hRL = height_null( pRLeft );
1633 node_type * pRRight = child( pRight, right_child );
1634 int hRR = height_null( pRRight );
1636 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1639 assert( pRLeft != nullptr );
1640 node_scoped_lock lrl( m_Monitor, *pRLeft );
1641 if ( pRight->m_pLeft.load( memory_model::memory_order_relaxed ) != pRLeft )
1642 return pNode; // retry
1644 hRL = height( pRLeft );
1646 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1648 node_type * pRLRight = child( pRLeft, right_child );
1649 int hRLR = height_null( pRLRight );
1650 int balance = hRR - hRLR;
1651 if ( balance >= -1 && balance <= 1 && !((hRR == 0 || hRLR == 0) && !pRight->is_valued( memory_model::memory_order_relaxed )))
1652 return rotate_left_over_right_locked( pParent, pNode, hL, pRight, pRLeft, hRR, hRLR );
1654 return rebalance_to_right_locked( pNode, pRight, pRLeft, hRR );
1658 static void begin_change( node_type * pNode, version_type version )
1660 pNode->version( version | node_type::shrinking, memory_model::memory_order_release );
1662 static void end_change( node_type * pNode, version_type version )
1664 // Clear shrinking and unlinked flags and increment version
1665 pNode->version( (version | node_type::version_flags) + 1, memory_model::memory_order_release );
1668 node_type * rotate_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLR )
1670 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1671 node_type * pParentLeft = child( pParent, left_child );
1673 begin_change( pNode, nodeVersion );
1675 pNode->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1676 if ( pLRight != nullptr )
1677 pLRight->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1679 pLeft->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1680 pNode->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
1682 if ( pParentLeft == pNode )
1683 pParent->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1685 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1686 pParent->m_pRight.store( pLeft, memory_model::memory_order_relaxed );
1688 pLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1690 // fix up heights links
1691 int hNode = 1 + std::max( hLR, hR );
1692 set_height( pNode, hNode );
1693 set_height( pLeft, 1 + std::max( hLL, hNode ));
1695 end_change( pNode, nodeVersion );
1696 m_stat.onRotateRight();
1698 // We have damaged pParent, pNode (now parent.child.right), and pLeft (now
1699 // parent.child). pNode is the deepest. Perform as many fixes as we can
1700 // with the locks we've got.
1702 // We've already fixed the height for pNode, but it might still be outside
1703 // our allowable balance range. In that case a simple fix_height_locked()
1705 int nodeBalance = hLR - hR;
1706 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1707 // we need another rotation at pNode
1711 // we've fixed balance and height damage for pNode, now handle
1712 // extra-routing node damage
1713 if ( (pLRight == nullptr || hR == 0) && !pNode->is_valued(memory_model::memory_order_relaxed)) {
1714 // we need to remove pNode and then repair
1718 // we've already fixed the height at pLeft, do we need a rotation here?
1719 int leftBalance = hLL - hNode;
1720 if ( leftBalance < -1 || leftBalance > 1 )
1723 // pLeft might also have routing node damage (if pLeft.left was null)
1724 if ( hLL == 0 && !pLeft->is_valued( memory_model::memory_order_relaxed ))
1727 // try to fix the parent height while we've still got the lock
1728 return fix_height_locked( pParent );
1731 node_type * rotate_left_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRL, int hRR )
1733 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1734 node_type * pParentLeft = child( pParent, left_child );
1736 begin_change( pNode, nodeVersion );
1738 // fix up pNode links, careful to be compatible with concurrent traversal for all but pNode
1739 pNode->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1740 if ( pRLeft != nullptr )
1741 pRLeft->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1743 pRight->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1744 pNode->m_pParent.store( pRight, memory_model::memory_order_relaxed );
1746 if ( pParentLeft == pNode )
1747 pParent->m_pLeft.store( pRight, memory_model::memory_order_relaxed );
1749 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1750 pParent->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1752 pRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1755 int hNode = 1 + std::max( hL, hRL );
1756 set_height( pNode, hNode );
1757 set_height( pRight, 1 + std::max( hNode, hRR ));
1759 end_change( pNode, nodeVersion );
1760 m_stat.onRotateLeft();
1762 int nodeBalance = hRL - hL;
1763 if ( nodeBalance < -1 || nodeBalance > 1 )
1766 if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1769 int rightBalance = hRR - hNode;
1770 if ( rightBalance < -1 || rightBalance > 1 )
1773 if ( hRR == 0 && !pRight->is_valued( memory_model::memory_order_relaxed ))
1776 return fix_height_locked( pParent );
1779 node_type * rotate_right_over_left_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLRL )
1781 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1782 version_type leftVersion = pLeft->version( memory_model::memory_order_relaxed );
1784 node_type * pPL = child( pParent, left_child );
1785 node_type * pLRL = child( pLRight, left_child );
1786 node_type * pLRR = child( pLRight, right_child );
1787 int hLRR = height_null( pLRR );
1789 begin_change( pNode, nodeVersion );
1790 begin_change( pLeft, leftVersion );
1792 // fix up pNode links, careful about the order!
1793 pNode->m_pLeft.store( pLRR, memory_model::memory_order_relaxed );
1794 if ( pLRR != nullptr )
1795 pLRR->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1797 pLeft->m_pRight.store( pLRL, memory_model::memory_order_relaxed );
1798 if ( pLRL != nullptr )
1799 pLRL->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
1801 pLRight->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1802 pLeft->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
1803 pLRight->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1804 pNode->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
1807 pParent->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1809 assert( child( pParent, right_child ) == pNode );
1810 pParent->m_pRight.store( pLRight, memory_model::memory_order_relaxed );
1812 pLRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1815 int hNode = 1 + std::max( hLRR, hR );
1816 set_height( pNode, hNode );
1817 int hLeft = 1 + std::max( hLL, hLRL );
1818 set_height( pLeft, hLeft );
1819 set_height( pLRight, 1 + std::max( hLeft, hNode ));
1821 end_change( pNode, nodeVersion );
1822 end_change( pLeft, leftVersion );
1823 m_stat.onRotateRightOverLeft();
1825 // caller should have performed only a single rotation if pLeft was going
1826 // to end up damaged
1827 assert( hLL - hLRL <= 1 && hLRL - hLL <= 1 );
1828 assert( !((hLL == 0 || pLRL == nullptr) && !pLeft->is_valued( memory_model::memory_order_relaxed )));
1830 // We have damaged pParent, pLR (now parent.child), and pNode (now
1831 // parent.child.right). pNode is the deepest. Perform as many fixes as we
1832 // can with the locks we've got.
1834 // We've already fixed the height for pNode, but it might still be outside
1835 // our allowable balance range. In that case a simple fix_height_locked()
1837 int nodeBalance = hLRR - hR;
1838 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1839 // we need another rotation at pNode
1843 // pNode might also be damaged by being an unnecessary routing node
1844 if ( (pLRR == nullptr || hR == 0) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1845 // repair involves splicing out pNode and maybe more rotations
1849 // we've already fixed the height at pLRight, do we need a rotation here?
1850 int balanceLR = hLeft - hNode;
1851 if ( balanceLR < -1 || balanceLR > 1 )
1854 // try to fix the parent height while we've still got the lock
1855 return fix_height_locked( pParent );
1858 node_type * rotate_left_over_right_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRR, int hRLR )
1860 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1861 version_type rightVersion = pRight->version( memory_model::memory_order_relaxed );
1863 node_type * pPL = child( pParent, left_child );
1864 node_type * pRLL = child( pRLeft, left_child );
1865 node_type * pRLR = child( pRLeft, right_child );
1866 int hRLL = height_null( pRLL );
1868 begin_change( pNode, nodeVersion );
1869 begin_change( pRight, rightVersion );
1871 // fix up pNode links, careful about the order!
1872 pNode->m_pRight.store( pRLL, memory_model::memory_order_relaxed );
1873 if ( pRLL != nullptr )
1874 pRLL->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1876 pRight->m_pLeft.store( pRLR, memory_model::memory_order_relaxed );
1877 if ( pRLR != nullptr )
1878 pRLR->m_pParent.store( pRight, memory_model::memory_order_relaxed );
1880 pRLeft->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1881 pRight->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
1882 pRLeft->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1883 pNode->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
1886 pParent->m_pLeft.store( pRLeft, memory_model::memory_order_relaxed );
1888 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1889 pParent->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1891 pRLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1894 int hNode = 1 + std::max( hL, hRLL );
1895 set_height( pNode, hNode );
1896 int hRight = 1 + std::max( hRLR, hRR );
1897 set_height( pRight, hRight );
1898 set_height( pRLeft, 1 + std::max( hNode, hRight ));
1900 end_change( pNode, nodeVersion );
1901 end_change( pRight, rightVersion );
1902 m_stat.onRotateLeftOverRight();
1904 assert( hRR - hRLR <= 1 && hRLR - hRR <= 1 );
1906 int nodeBalance = hRLL - hL;
1907 if ( nodeBalance < -1 || nodeBalance > 1 )
1909 if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1912 int balRL = hRight - hNode;
1913 if ( balRL < -1 || balRL > 1 )
1916 return fix_height_locked( pParent );
1921 }} // namespace cds::container
1923 #endif // #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H