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 )
157 return pNode->child( nDir ).load( order );
160 static node_type * parent( node_type * pNode, atomics::memory_order order )
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, memory_model::memory_order_relaxed );
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
765 size_t hLeft = do_check_consistency( child( pNode, left_child, memory_model::memory_order_relaxed ), nLevel + 1, f, nErrors );
766 size_t hRight = do_check_consistency( child( pNode, right_child, memory_model::memory_order_relaxed ), nLevel + 1, f, nErrors );
768 if ( hLeft >= hRight ) {
769 if ( hLeft - hRight > 1 ) {
770 f( nLevel, hLeft, hRight );
776 if ( hRight - hLeft > 1 ) {
777 f( nLevel, hLeft, hRight );
786 template <typename Q, typename Compare, typename Func>
787 bool do_find( Q& key, Compare cmp, Func f ) const
792 result = try_find( key, cmp, f, m_pRoot, 1, 0 );
794 assert( result != find_result::retry );
795 return result == find_result::found;
798 template <typename K, typename Compare, typename Func>
799 int do_update( K const& key, Compare cmp, Func funcUpdate, int nFlags )
801 check_deadlock_policy::check();
803 rcu_disposer removed_list;
806 return try_update_root( key, cmp, nFlags, funcUpdate, removed_list );
810 template <typename K, typename Compare, typename Func>
811 bool do_remove( K const& key, Compare cmp, Func func )
813 // Func must return true if the value was disposed
814 // or false if the value was extracted
816 check_deadlock_policy::check();
818 rcu_disposer removed_list;
821 return try_remove_root( key, cmp, func, removed_list );
825 template <typename Func>
826 mapped_type do_extract_min( Func f )
828 mapped_type pExtracted = nullptr;
831 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
836 template <typename Func>
837 mapped_type do_extract_max( Func f )
839 mapped_type pExtracted = nullptr;
842 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
847 template <typename Func>
848 void do_extract_minmax( int nDir, Func func )
850 check_deadlock_policy::check();
852 rcu_disposer removed_list;
856 int result = update_flags::failed;
858 // get right child of root
859 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
861 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
862 if ( nChildVersion & node_type::shrinking ) {
863 m_stat.onRemoveRootWaitShrinking();
864 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
865 result = update_flags::retry;
867 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
868 result = try_extract_minmax( nDir, func, m_pRoot, pChild, nChildVersion, removed_list );
871 } while ( result == update_flags::retry );
875 template <typename Q>
876 mapped_type do_extract( Q const& key )
878 mapped_type pExtracted = nullptr;
882 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
887 template <typename Q, typename Less>
888 mapped_type do_extract_with( Q const& key, Less pred )
891 mapped_type pExtracted = nullptr;
894 cds::opt::details::make_comparator_from_less<Less>(),
895 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
904 template <typename Q, typename Compare, typename Func>
905 find_result try_find( Q const& key, Compare cmp, Func f, node_type * pNode, int nDir, version_type nVersion ) const
907 assert( gc::is_locked() );
911 node_type * pChild = child( pNode, nDir, memory_model::memory_order_relaxed );
913 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
914 m_stat.onFindRetry();
915 return find_result::retry;
918 m_stat.onFindFailed();
919 return find_result::not_found;
922 int nCmp = cmp( key, pChild->m_key );
924 if ( pChild->is_valued( memory_model::memory_order_relaxed ) ) {
926 node_scoped_lock l( m_Monitor, *pChild );
927 if ( pChild->is_valued( memory_model::memory_order_relaxed )) {
929 m_stat.onFindSuccess();
930 return find_result::found;
935 m_stat.onFindFailed();
936 return find_result::not_found;
939 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
940 if ( nChildVersion & node_type::shrinking ) {
941 m_stat.onFindWaitShrinking();
942 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
944 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
945 m_stat.onFindRetry();
946 return find_result::retry;
949 else if ( nChildVersion != node_type::unlinked ) {
951 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
952 m_stat.onFindRetry();
953 return find_result::retry;
956 find_result found = try_find( key, cmp, f, pChild, nCmp, nChildVersion );
957 if ( found != find_result::retry )
963 template <typename K, typename Compare, typename Func>
964 int try_update_root( K const& key, Compare cmp, int nFlags, Func funcUpdate, rcu_disposer& disp )
966 assert( gc::is_locked() );
970 // get right child of root
971 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
973 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
974 if ( nChildVersion & node_type::shrinking ) {
975 m_stat.onUpdateRootWaitShrinking();
976 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
977 result = update_flags::retry;
979 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
980 result = try_update( key, cmp, nFlags, funcUpdate, m_pRoot, pChild, nChildVersion, disp );
983 result = update_flags::retry;
987 if ( nFlags & update_flags::allow_insert ) {
988 // insert into tree as right child of the root
990 node_scoped_lock l( m_Monitor, *m_pRoot );
991 if ( child( m_pRoot, right_child, memory_model::memory_order_acquire ) != nullptr ) {
992 result = update_flags::retry;
996 node_type * pNew = alloc_node( key, 1, 0, m_pRoot, nullptr, nullptr );
997 mapped_type pVal = funcUpdate( pNew );
998 assert( pVal != nullptr );
999 pNew->m_pValue.store( pVal, memory_model::memory_order_release );
1001 m_pRoot->child( pNew, right_child, memory_model::memory_order_relaxed );
1002 m_pRoot->height( 2, memory_model::memory_order_relaxed );
1006 m_stat.onInsertSuccess();
1007 return update_flags::result_inserted;
1010 return update_flags::failed;
1012 } while ( result == update_flags::retry );
1016 template <typename K, typename Compare, typename Func>
1017 bool try_remove_root( K const& key, Compare cmp, Func func, rcu_disposer& disp )
1019 assert( gc::is_locked() );
1023 // get right child of root
1024 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
1026 version_type nChildVersion = pChild->version( memory_model::memory_order_relaxed );
1027 if ( nChildVersion & node_type::shrinking ) {
1028 m_stat.onRemoveRootWaitShrinking();
1029 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1030 result = update_flags::retry;
1032 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
1033 result = try_remove( key, cmp, func, m_pRoot, pChild, nChildVersion, disp );
1036 result = update_flags::retry;
1040 } while ( result == update_flags::retry );
1042 return result == update_flags::result_removed;
1045 template <typename K, typename Compare, typename Func>
1046 int try_update( K const& key, Compare cmp, int nFlags, Func funcUpdate, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1048 assert( gc::is_locked() );
1049 assert( nVersion != node_type::unlinked );
1050 CDS_UNUSED( pParent );
1052 int nCmp = cmp( key, pNode->m_key );
1054 if ( nFlags & update_flags::allow_update ) {
1055 return try_update_node( funcUpdate, pNode, disp );
1057 return update_flags::failed;
1062 node_type * pChild = child( pNode, nCmp, memory_model::memory_order_relaxed );
1063 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1064 m_stat.onUpdateRetry();
1065 return update_flags::retry;
1068 if ( pChild == nullptr ) {
1070 if ( nFlags & update_flags::allow_insert )
1071 result = try_insert_node( key, funcUpdate, pNode, nCmp, nVersion, disp );
1073 result = update_flags::failed;
1077 result = update_flags::retry;
1078 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1079 if ( nChildVersion & node_type::shrinking ) {
1080 m_stat.onUpdateWaitShrinking();
1081 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1084 else if ( pChild == child( pNode, nCmp, memory_model::memory_order_relaxed )) {
1085 // this second read is important, because it is protected by nChildVersion
1087 // validate the read that our caller took to get to node
1088 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1089 m_stat.onUpdateRetry();
1090 return update_flags::retry;
1093 // At this point we know that the traversal our parent took to get to node is still valid.
1094 // The recursive implementation will validate the traversal from node to
1095 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1096 // This means that we are no longer vulnerable to node shrinks, and we don't need
1097 // to validate node version any more.
1098 result = try_update( key, cmp, nFlags, funcUpdate, pNode, pChild, nChildVersion, disp );
1101 } while ( result == update_flags::retry );
1105 template <typename K, typename Compare, typename Func>
1106 int try_remove( K const& key, Compare cmp, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1108 assert( gc::is_locked() );
1109 assert( nVersion != node_type::unlinked );
1111 int nCmp = cmp( key, pNode->m_key );
1113 return try_remove_node( pParent, pNode, nVersion, func, disp );
1117 node_type * pChild = child( pNode, nCmp, memory_model::memory_order_relaxed );
1118 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1119 m_stat.onRemoveRetry();
1120 return update_flags::retry;
1123 if ( pChild == nullptr ) {
1124 return update_flags::failed;
1128 result = update_flags::retry;
1129 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1130 if ( nChildVersion & node_type::shrinking ) {
1131 m_stat.onRemoveWaitShrinking();
1132 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1135 else if ( pChild == child( pNode, nCmp, memory_model::memory_order_relaxed )) {
1136 // this second read is important, because it is protected by nChildVersion
1138 // validate the read that our caller took to get to node
1139 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1140 m_stat.onRemoveRetry();
1141 return update_flags::retry;
1144 // At this point we know that the traversal our parent took to get to node is still valid.
1145 // The recursive implementation will validate the traversal from node to
1146 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1147 // This means that we are no longer vulnerable to node shrinks, and we don't need
1148 // to validate node version any more.
1149 result = try_remove( key, cmp, func, pNode, pChild, nChildVersion, disp );
1152 } while ( result == update_flags::retry );
1156 template <typename Func>
1157 int try_extract_minmax( int nDir, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1159 assert( gc::is_locked() );
1160 assert( nVersion != node_type::unlinked );
1164 node_type * pChild = child( pNode, nDir, memory_model::memory_order_relaxed );
1165 if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
1166 m_stat.onRemoveRetry();
1167 return update_flags::retry;
1170 if ( pChild == nullptr ) {
1172 return try_remove_node( pParent, pNode, nVersion, func, disp );
1175 result = update_flags::retry;
1176 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1177 if ( nChildVersion & node_type::shrinking ) {
1178 m_stat.onRemoveWaitShrinking();
1179 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1182 else if ( pChild == child( pNode, nDir, memory_model::memory_order_relaxed )) {
1183 // this second read is important, because it is protected by nChildVersion
1185 // validate the read that our caller took to get to node
1186 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion ) {
1187 m_stat.onRemoveRetry();
1188 return update_flags::retry;
1191 // At this point we know that the traversal our parent took to get to node is still valid.
1192 // The recursive implementation will validate the traversal from node to
1193 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1194 // This means that we are no longer vulnerable to node shrinks, and we don't need
1195 // to validate node version any more.
1196 result = try_extract_minmax( nDir, func, pNode, pChild, nChildVersion, disp );
1199 } while ( result == update_flags::retry );
1203 template <typename K, typename Func>
1204 int try_insert_node( K const& key, Func funcUpdate, node_type * pNode, int nDir, version_type nVersion, rcu_disposer& disp )
1208 auto fnCreateNode = [&funcUpdate]( node_type * pNew ) {
1209 mapped_type pVal = funcUpdate( pNew );
1210 assert( pVal != nullptr );
1211 pNew->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1214 if ( c_bRelaxedInsert ) {
1215 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1216 || child( pNode, nDir, memory_model::memory_order_relaxed ) != nullptr )
1218 m_stat.onInsertRetry();
1219 return update_flags::retry;
1222 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1225 node_type * pDamaged;
1227 assert( pNode != nullptr );
1228 node_scoped_lock l( m_Monitor, *pNode );
1230 if ( pNode->version( memory_model::memory_order_relaxed ) != nVersion
1231 || child( pNode, nDir, memory_model::memory_order_relaxed ) != nullptr )
1233 if ( c_bRelaxedInsert ) {
1234 mapped_type pVal = pNew->m_pValue.load( memory_model::memory_order_relaxed );
1235 pNew->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1238 m_stat.onRelaxedInsertFailed();
1241 m_stat.onInsertRetry();
1242 return update_flags::retry;
1245 if ( !c_bRelaxedInsert )
1246 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1248 pNode->child( pNew, nDir, memory_model::memory_order_relaxed );
1249 pDamaged = fix_height_locked( pNode );
1253 m_stat.onInsertSuccess();
1256 fix_height_and_rebalance( pDamaged, disp );
1257 m_stat.onInsertRebalanceRequired();
1260 return update_flags::result_inserted;
1263 template <typename Func>
1264 int try_update_node( Func funcUpdate, node_type * pNode, rcu_disposer& disp )
1267 assert( pNode != nullptr );
1269 node_scoped_lock l( m_Monitor, *pNode );
1271 if ( pNode->is_unlinked( memory_model::memory_order_relaxed )) {
1272 m_stat.onUpdateUnlinked();
1273 return update_flags::retry;
1276 pOld = pNode->value( memory_model::memory_order_relaxed );
1277 mapped_type pVal = funcUpdate( pNode );
1281 assert( pVal != nullptr );
1282 pNode->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1287 disp.dispose_value(pOld);
1288 m_stat.onDisposeValue();
1291 m_stat.onUpdateSuccess();
1292 return update_flags::result_updated;
1295 template <typename Func>
1296 int try_remove_node( node_type * pParent, node_type * pNode, version_type nVersion, Func func, rcu_disposer& disp )
1298 assert( pParent != nullptr );
1299 assert( pNode != nullptr );
1301 if ( !pNode->is_valued( atomics::memory_order_relaxed ) )
1302 return update_flags::failed;
1304 if ( child( pNode, left_child, memory_model::memory_order_relaxed ) == nullptr
1305 || child( pNode, right_child, memory_model::memory_order_relaxed ) == nullptr )
1307 node_type * pDamaged;
1310 node_scoped_lock lp( m_Monitor, *pParent );
1311 if ( pParent->is_unlinked( atomics::memory_order_relaxed ) || parent( pNode, memory_model::memory_order_relaxed ) != pParent )
1312 return update_flags::retry;
1315 node_scoped_lock ln( m_Monitor, *pNode );
1316 pOld = pNode->value( memory_model::memory_order_relaxed );
1317 if ( !( pNode->version( memory_model::memory_order_relaxed ) == nVersion
1319 && try_unlink_locked( pParent, pNode, disp )))
1321 return update_flags::retry;
1324 pDamaged = fix_height_locked( pParent );
1328 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1329 m_stat.onDisposeValue();
1331 m_stat.onExtractValue();
1334 fix_height_and_rebalance( pDamaged, disp );
1335 m_stat.onRemoveRebalanceRequired();
1337 return update_flags::result_removed;
1340 int result = update_flags::retry;
1343 node_scoped_lock ln( m_Monitor, *pNode );
1344 pOld = pNode->value( atomics::memory_order_relaxed );
1345 if ( pNode->version( atomics::memory_order_relaxed ) == nVersion && pOld ) {
1346 pNode->m_pValue.store( nullptr, atomics::memory_order_relaxed );
1347 result = update_flags::result_removed;
1351 if ( result == update_flags::result_removed ) {
1353 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1354 m_stat.onDisposeValue();
1356 m_stat.onExtractValue();
1363 bool try_unlink_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1365 // pParent and pNode must be locked
1366 assert( !pParent->is_unlinked(memory_model::memory_order_relaxed) );
1368 node_type * pParentLeft = child( pParent, left_child, memory_model::memory_order_relaxed );
1369 node_type * pParentRight = child( pParent, right_child, memory_model::memory_order_relaxed );
1370 if ( pNode != pParentLeft && pNode != pParentRight ) {
1371 // node is no longer a child of parent
1375 assert( !pNode->is_unlinked( memory_model::memory_order_relaxed ) );
1376 assert( pParent == parent( pNode, memory_model::memory_order_relaxed));
1378 node_type * pLeft = child( pNode, left_child, memory_model::memory_order_relaxed );
1379 node_type * pRight = child( pNode, right_child, memory_model::memory_order_relaxed );
1380 if ( pLeft != nullptr && pRight != nullptr ) {
1381 // splicing is no longer possible
1384 node_type * pSplice = pLeft ? pLeft : pRight;
1386 if ( pParentLeft == pNode )
1387 pParent->m_pLeft.store( pSplice, memory_model::memory_order_relaxed );
1389 pParent->m_pRight.store( pSplice, memory_model::memory_order_relaxed );
1392 pSplice->m_pParent.store( pParent, memory_model::memory_order_release );
1394 // Mark the node as unlinked
1395 pNode->version( node_type::unlinked, memory_model::memory_order_release );
1397 // The value will be disposed by calling function
1398 pNode->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1400 disp.dispose( pNode );
1401 m_stat.onDisposeNode();
1408 private: // rotations
1410 int estimate_node_condition( node_type * pNode )
1412 node_type * pLeft = child( pNode, left_child, memory_model::memory_order_relaxed );
1413 node_type * pRight = child( pNode, right_child, memory_model::memory_order_relaxed );
1415 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1416 return unlink_required;
1418 int h = pNode->height( memory_model::memory_order_relaxed );
1419 int hL = pLeft ? pLeft->height( memory_model::memory_order_relaxed ) : 0;
1420 int hR = pRight ? pRight->height( memory_model::memory_order_relaxed ) : 0;
1422 int hNew = 1 + std::max( hL, hR );
1423 int nBalance = hL - hR;
1425 if ( nBalance < -1 || nBalance > 1 )
1426 return rebalance_required;
1428 return h != hNew ? hNew : nothing_required;
1431 node_type * fix_height( node_type * pNode )
1433 assert( pNode != nullptr );
1434 node_scoped_lock l( m_Monitor, *pNode );
1435 return fix_height_locked( pNode );
1438 node_type * fix_height_locked( node_type * pNode )
1440 // pNode must be locked!!!
1441 int h = estimate_node_condition( pNode );
1443 case rebalance_required:
1444 case unlink_required:
1446 case nothing_required:
1449 pNode->height( h, memory_model::memory_order_relaxed );
1450 return parent( pNode, memory_model::memory_order_relaxed );
1454 void fix_height_and_rebalance( node_type * pNode, rcu_disposer& disp )
1456 while ( pNode && parent( pNode, memory_model::memory_order_relaxed )) {
1457 int nCond = estimate_node_condition( pNode );
1458 if ( nCond == nothing_required || pNode->is_unlinked( memory_model::memory_order_relaxed ) )
1461 if ( nCond != unlink_required && nCond != rebalance_required )
1462 pNode = fix_height( pNode );
1464 node_type * pParent = parent( pNode, memory_model::memory_order_relaxed );
1465 assert( pParent != nullptr );
1467 node_scoped_lock lp( m_Monitor, *pParent );
1468 if ( !pParent->is_unlinked( memory_model::memory_order_relaxed )
1469 && parent( pNode, memory_model::memory_order_relaxed ) == pParent )
1471 node_scoped_lock ln( m_Monitor, *pNode );
1472 pNode = rebalance_locked( pParent, pNode, disp );
1479 node_type * rebalance_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1481 // pParent and pNode should be locked.
1482 // Returns a damaged node, or nullptr if no more rebalancing is necessary
1483 assert( parent( pNode, memory_model::memory_order_relaxed ) == pParent );
1485 node_type * pLeft = child( pNode, left_child, memory_model::memory_order_relaxed );
1486 node_type * pRight = child( pNode, right_child, memory_model::memory_order_relaxed );
1488 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1489 if ( try_unlink_locked( pParent, pNode, disp ))
1490 return fix_height_locked( pParent );
1492 // retry needed for pNode
1497 assert( child( pParent, left_child, memory_model::memory_order_relaxed ) == pNode
1498 || child( pParent, right_child, memory_model::memory_order_relaxed ) == pNode );
1500 int h = pNode->height( memory_model::memory_order_relaxed );
1501 int hL = pLeft ? pLeft->height( memory_model::memory_order_relaxed ) : 0;
1502 int hR = pRight ? pRight->height( memory_model::memory_order_relaxed ) : 0;
1503 int hNew = 1 + std::max( hL, hR );
1504 int balance = hL - hR;
1507 return rebalance_to_right_locked( pParent, pNode, pLeft, hR );
1508 else if ( balance < -1 )
1509 return rebalance_to_left_locked( pParent, pNode, pRight, hL );
1510 else if ( hNew != h ) {
1511 pNode->height( hNew, memory_model::memory_order_relaxed );
1513 // pParent is already locked
1514 return fix_height_locked( pParent );
1520 node_type * rebalance_to_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR )
1522 assert( parent( pNode, memory_model::memory_order_relaxed ) == pParent );
1523 assert( child( pParent, left_child, memory_model::memory_order_relaxed ) == pNode
1524 || child( pParent, right_child, memory_model::memory_order_relaxed ) == pNode );
1526 // pParent and pNode is locked yet
1527 // pNode->pLeft is too large, we will rotate-right.
1528 // If pLeft->pRight is taller than pLeft->pLeft, then we will first rotate-left pLeft.
1531 assert( pLeft != nullptr );
1532 node_scoped_lock l( m_Monitor, *pLeft );
1533 if ( pNode->m_pLeft.load( memory_model::memory_order_relaxed ) != pLeft )
1534 return pNode; // retry for pNode
1536 int hL = pLeft->height( memory_model::memory_order_relaxed );
1538 return pNode; // retry
1540 node_type * pLRight = child( pLeft, right_child, memory_model::memory_order_relaxed );
1541 int hLR = pLRight ? pLRight->height( memory_model::memory_order_relaxed ) : 0;
1542 node_type * pLLeft = child( pLeft, left_child, memory_model::memory_order_relaxed );
1543 int hLL = pLLeft ? pLLeft->height( memory_model::memory_order_relaxed ) : 0;
1547 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1550 assert( pLRight != nullptr );
1552 node_scoped_lock lr( m_Monitor, *pLRight );
1553 if ( pLeft->m_pRight.load( memory_model::memory_order_relaxed ) != pLRight )
1554 return pNode; // retry
1556 hLR = pLRight->height( memory_model::memory_order_relaxed );
1558 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1560 node_type * pLRLeft = child( pLRight, left_child, memory_model::memory_order_relaxed );
1561 int hLRL = pLRLeft ? pLRLeft->height( memory_model::memory_order_relaxed ) : 0;
1562 int balance = hLL - hLRL;
1563 if ( balance >= -1 && balance <= 1 && !((hLL == 0 || hLRL == 0) && !pLeft->is_valued(memory_model::memory_order_relaxed))) {
1564 // nParent.child.left won't be damaged after a double rotation
1565 return rotate_right_over_left_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLRL );
1569 // focus on pLeft, if necessary pNode will be balanced later
1570 return rebalance_to_left_locked( pNode, pLeft, pLRight, hLL );
1575 node_type * rebalance_to_left_locked( node_type * pParent, node_type * pNode, node_type * pRight, int hL )
1577 assert( parent( pNode, memory_model::memory_order_relaxed ) == pParent );
1578 assert( child( pParent, left_child, memory_model::memory_order_relaxed ) == pNode
1579 || child( pParent, right_child, memory_model::memory_order_relaxed ) == pNode );
1581 // pParent and pNode is locked yet
1583 assert( pRight != nullptr );
1584 node_scoped_lock l( m_Monitor, *pRight );
1585 if ( pNode->m_pRight.load( memory_model::memory_order_relaxed ) != pRight )
1586 return pNode; // retry for pNode
1588 int hR = pRight->height( memory_model::memory_order_relaxed );
1589 if ( hL - hR >= -1 )
1590 return pNode; // retry
1592 node_type * pRLeft = child( pRight, left_child, memory_model::memory_order_relaxed );
1593 int hRL = pRLeft ? pRLeft->height( memory_model::memory_order_relaxed ) : 0;
1594 node_type * pRRight = child( pRight, right_child, memory_model::memory_order_relaxed );
1595 int hRR = pRRight ? pRRight->height( memory_model::memory_order_relaxed ) : 0;
1597 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1600 assert( pRLeft != nullptr );
1601 node_scoped_lock lrl( m_Monitor, *pRLeft );
1602 if ( pRight->m_pLeft.load( memory_model::memory_order_relaxed ) != pRLeft )
1603 return pNode; // retry
1605 hRL = pRLeft->height( memory_model::memory_order_relaxed );
1607 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1609 node_type * pRLRight = child( pRLeft, right_child, memory_model::memory_order_relaxed );
1610 int hRLR = pRLRight ? pRLRight->height( memory_model::memory_order_relaxed ) : 0;
1611 int balance = hRR - hRLR;
1612 if ( balance >= -1 && balance <= 1 && !((hRR == 0 || hRLR == 0) && !pRight->is_valued( memory_model::memory_order_relaxed )))
1613 return rotate_left_over_right_locked( pParent, pNode, hL, pRight, pRLeft, hRR, hRLR );
1615 return rebalance_to_right_locked( pNode, pRight, pRLeft, hRR );
1619 static void begin_change( node_type * pNode, version_type version )
1621 pNode->version( version | node_type::shrinking, memory_model::memory_order_release );
1623 static void end_change( node_type * pNode, version_type version )
1625 // Clear shrinking and unlinked flags and increment version
1626 pNode->version( (version | node_type::version_flags) + 1, memory_model::memory_order_release );
1629 node_type * rotate_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLR )
1631 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1632 node_type * pParentLeft = child( pParent, left_child, memory_model::memory_order_relaxed );
1634 begin_change( pNode, nodeVersion );
1636 pNode->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1637 if ( pLRight != nullptr )
1638 pLRight->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1640 pLeft->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1641 pNode->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
1643 if ( pParentLeft == pNode )
1644 pParent->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1646 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1647 pParent->m_pRight.store( pLeft, memory_model::memory_order_relaxed );
1649 pLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1651 // fix up heights links
1652 int hNode = 1 + std::max( hLR, hR );
1653 pNode->height( hNode, memory_model::memory_order_relaxed );
1654 pLeft->height( 1 + std::max( hLL, hNode ), memory_model::memory_order_relaxed );
1656 end_change( pNode, nodeVersion );
1657 m_stat.onRotateRight();
1659 // We have damaged pParent, pNode (now parent.child.right), and pLeft (now
1660 // parent.child). pNode is the deepest. Perform as many fixes as we can
1661 // with the locks we've got.
1663 // We've already fixed the height for pNode, but it might still be outside
1664 // our allowable balance range. In that case a simple fix_height_locked()
1666 int nodeBalance = hLR - hR;
1667 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1668 // we need another rotation at pNode
1672 // we've fixed balance and height damage for pNode, now handle
1673 // extra-routing node damage
1674 if ( (pLRight == nullptr || hR == 0) && !pNode->is_valued(memory_model::memory_order_relaxed)) {
1675 // we need to remove pNode and then repair
1679 // we've already fixed the height at pLeft, do we need a rotation here?
1680 int leftBalance = hLL - hNode;
1681 if ( leftBalance < -1 || leftBalance > 1 )
1684 // pLeft might also have routing node damage (if pLeft.left was null)
1685 if ( hLL == 0 && !pLeft->is_valued( memory_model::memory_order_relaxed ))
1688 // try to fix the parent height while we've still got the lock
1689 return fix_height_locked( pParent );
1692 node_type * rotate_left_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRL, int hRR )
1694 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1695 node_type * pParentLeft = child( pParent, left_child, memory_model::memory_order_relaxed );
1697 begin_change( pNode, nodeVersion );
1699 // fix up pNode links, careful to be compatible with concurrent traversal for all but pNode
1700 pNode->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1701 if ( pRLeft != nullptr )
1702 pRLeft->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1704 pRight->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1705 pNode->m_pParent.store( pRight, memory_model::memory_order_relaxed );
1707 if ( pParentLeft == pNode )
1708 pParent->m_pLeft.store( pRight, memory_model::memory_order_relaxed );
1710 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1711 pParent->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1713 pRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1716 int hNode = 1 + std::max( hL, hRL );
1717 pNode->height( hNode, memory_model::memory_order_relaxed );
1718 pRight->height( 1 + std::max( hNode, hRR ), memory_model::memory_order_relaxed );
1720 end_change( pNode, nodeVersion );
1721 m_stat.onRotateLeft();
1723 int nodeBalance = hRL - hL;
1724 if ( nodeBalance < -1 || nodeBalance > 1 )
1727 if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1730 int rightBalance = hRR - hNode;
1731 if ( rightBalance < -1 || rightBalance > 1 )
1734 if ( hRR == 0 && !pRight->is_valued( memory_model::memory_order_relaxed ))
1737 return fix_height_locked( pParent );
1740 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 )
1742 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1743 version_type leftVersion = pLeft->version( memory_model::memory_order_relaxed );
1745 node_type * pPL = child( pParent, left_child, memory_model::memory_order_relaxed );
1746 node_type * pLRL = child( pLRight, left_child, memory_model::memory_order_relaxed );
1747 node_type * pLRR = child( pLRight, right_child, memory_model::memory_order_relaxed );
1748 int hLRR = pLRR ? pLRR->height( memory_model::memory_order_relaxed ) : 0;
1750 begin_change( pNode, nodeVersion );
1751 begin_change( pLeft, leftVersion );
1753 // fix up pNode links, careful about the order!
1754 pNode->m_pLeft.store( pLRR, memory_model::memory_order_relaxed );
1755 if ( pLRR != nullptr )
1756 pLRR->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1758 pLeft->m_pRight.store( pLRL, memory_model::memory_order_relaxed );
1759 if ( pLRL != nullptr )
1760 pLRL->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
1762 pLRight->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1763 pLeft->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
1764 pLRight->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1765 pNode->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
1768 pParent->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1770 assert( child( pParent, right_child, memory_model::memory_order_relaxed ) == pNode );
1771 pParent->m_pRight.store( pLRight, memory_model::memory_order_relaxed );
1773 pLRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1776 int hNode = 1 + std::max( hLRR, hR );
1777 pNode->height( hNode, memory_model::memory_order_relaxed );
1778 int hLeft = 1 + std::max( hLL, hLRL );
1779 pLeft->height( hLeft, memory_model::memory_order_relaxed );
1780 pLRight->height( 1 + std::max( hLeft, hNode ), memory_model::memory_order_relaxed );
1782 end_change( pNode, nodeVersion );
1783 end_change( pLeft, leftVersion );
1784 m_stat.onRotateRightOverLeft();
1786 // caller should have performed only a single rotation if pLeft was going
1787 // to end up damaged
1788 assert( hLL - hLRL <= 1 && hLRL - hLL <= 1 );
1789 assert( !((hLL == 0 || pLRL == nullptr) && !pLeft->is_valued( memory_model::memory_order_relaxed )));
1791 // We have damaged pParent, pLR (now parent.child), and pNode (now
1792 // parent.child.right). pNode is the deepest. Perform as many fixes as we
1793 // can with the locks we've got.
1795 // We've already fixed the height for pNode, but it might still be outside
1796 // our allowable balance range. In that case a simple fix_height_locked()
1798 int nodeBalance = hLRR - hR;
1799 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1800 // we need another rotation at pNode
1804 // pNode might also be damaged by being an unnecessary routing node
1805 if ( (pLRR == nullptr || hR == 0) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1806 // repair involves splicing out pNode and maybe more rotations
1810 // we've already fixed the height at pLRight, do we need a rotation here?
1811 int balanceLR = hLeft - hNode;
1812 if ( balanceLR < -1 || balanceLR > 1 )
1815 // try to fix the parent height while we've still got the lock
1816 return fix_height_locked( pParent );
1819 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 )
1821 version_type nodeVersion = pNode->version( memory_model::memory_order_relaxed );
1822 version_type rightVersion = pRight->version( memory_model::memory_order_relaxed );
1824 node_type * pPL = child( pParent, left_child, memory_model::memory_order_relaxed );
1825 node_type * pRLL = child( pRLeft, left_child, memory_model::memory_order_relaxed );
1826 node_type * pRLR = child( pRLeft, right_child, memory_model::memory_order_relaxed );
1827 int hRLL = pRLL ? pRLL->height( memory_model::memory_order_relaxed ) : 0;
1829 begin_change( pNode, nodeVersion );
1830 begin_change( pRight, rightVersion );
1832 // fix up pNode links, careful about the order!
1833 pNode->m_pRight.store( pRLL, memory_model::memory_order_relaxed );
1834 if ( pRLL != nullptr )
1835 pRLL->m_pParent.store( pNode, memory_model::memory_order_relaxed );
1837 pRight->m_pLeft.store( pRLR, memory_model::memory_order_relaxed );
1838 if ( pRLR != nullptr )
1839 pRLR->m_pParent.store( pRight, memory_model::memory_order_relaxed );
1841 pRLeft->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1842 pRight->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
1843 pRLeft->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1844 pNode->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
1847 pParent->m_pLeft.store( pRLeft, memory_model::memory_order_relaxed );
1849 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1850 pParent->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1852 pRLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
1855 int hNode = 1 + std::max( hL, hRLL );
1856 pNode->height( hNode, memory_model::memory_order_relaxed );
1857 int hRight = 1 + std::max( hRLR, hRR );
1858 pRight->height( hRight, memory_model::memory_order_relaxed );
1859 pRLeft->height( 1 + std::max( hNode, hRight ), memory_model::memory_order_relaxed );
1861 end_change( pNode, nodeVersion );
1862 end_change( pRight, rightVersion );
1863 m_stat.onRotateLeftOverRight();
1865 assert( hRR - hRLR <= 1 && hRLR - hRR <= 1 );
1867 int nodeBalance = hRLL - hL;
1868 if ( nodeBalance < -1 || nodeBalance > 1 )
1870 if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1873 int balRL = hRight - hNode;
1874 if ( balRL < -1 || balRL > 1 )
1877 return fix_height_locked( pParent );
1882 }} // namespace cds::container
1884 #endif // #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H