3 #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H
4 #define CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H
6 #include <cds/container/details/ellen_bintree_base.h>
7 #include <cds/intrusive/ellen_bintree_rcu.h>
9 namespace cds { namespace container {
11 /// Set based on Ellen's et al binary search tree (RCU specialization)
12 /** @ingroup cds_nonintrusive_set
13 @ingroup cds_nonintrusive_tree
14 @anchor cds_container_EllenBinTreeSet_rcu
17 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
19 %EllenBinTreeSet is an unbalanced leaf-oriented binary search tree that implements the <i>set</i>
20 abstract data type. Nodes maintains child pointers but not parent pointers.
21 Every internal node has exactly two children, and all data of type \p T currently in
22 the tree are stored in the leaves. Internal nodes of the tree are used to direct \p find
23 operation along the path to the correct leaf. The keys (of \p Key type) stored in internal nodes
24 may or may not be in the set. \p Key type is a subset of \p T type.
25 There should be exactly defined a key extracting functor for converting object of type \p T to
26 object of type \p Key.
28 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeSet can act as
29 a <i>priority queue</i>. In this case you should provide unique compound key, for example,
30 the priority value plus some uniformly distributed random value.
32 @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
33 for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
35 @note In the current implementation we do not use helping technique described in original paper.
36 So, the current implementation is near to fine-grained lock-based tree.
37 Helping will be implemented in future release
39 <b>Template arguments</b> :
40 - \p RCU - one of \ref cds_urcu_gc "RCU type"
41 - \p Key - key type, a subset of \p T
42 - \p T - type to be stored in tree's leaf nodes.
43 - \p Traits - set traits, default is \p ellen_bintree::traits.
44 It is possible to declare option-based tree with \p ellen_bintree::make_set_traits metafunction
45 instead of \p Traits template argument.
47 @note Before including <tt><cds/container/ellen_bintree_set_rcu.h></tt> you should include appropriate RCU header file,
48 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
50 @anchor cds_container_EllenBinTreeSet_rcu_less
51 <b>Predicate requirements</b>
53 opt::less, opt::compare and other predicates using with member fuctions should accept at least parameters
54 of type \p T and \p Key in any combination.
55 For example, for \p Foo struct with \p std::string key field the appropiate \p less functor is:
64 bool operator()( Foo const& v1, Foo const& v2 ) const
65 { return v1.m_strKey < v2.m_strKey ; }
67 bool operator()( Foo const& v, std::string const& s ) const
68 { return v.m_strKey < s ; }
70 bool operator()( std::string const& s, Foo const& v ) const
71 { return s < v.m_strKey ; }
73 // Support comparing std::string and char const *
74 bool operator()( std::string const& s, char const * p ) const
75 { return s.compare(p) < 0 ; }
77 bool operator()( Foo const& v, char const * p ) const
78 { return v.m_strKey.compare(p) < 0 ; }
80 bool operator()( char const * p, std::string const& s ) const
81 { return s.compare(p) > 0; }
83 bool operator()( char const * p, Foo const& v ) const
84 { return v.m_strKey.compare(p) > 0; }
93 #ifdef CDS_DOXYGEN_INVOKED
94 class Traits = ellen_bintree::traits
99 class EllenBinTreeSet< cds::urcu::gc<RCU>, Key, T, Traits >
100 #ifdef CDS_DOXYGEN_INVOKED
101 : public cds::intrusive::EllenBinTree< cds::urcu::gc<RCU>, Key, T, Traits >
103 : public ellen_bintree::details::make_ellen_bintree_set< cds::urcu::gc<RCU>, Key, T, Traits >::type
107 typedef ellen_bintree::details::make_ellen_bintree_set< cds::urcu::gc<RCU>, Key, T, Traits > maker;
108 typedef typename maker::type base_class;
112 typedef cds::urcu::gc<RCU> gc; ///< RCU Garbage collector
113 typedef Key key_type; ///< type of a key stored in internal nodes; key is a part of \p value_type
114 typedef T value_type; ///< type of value stored in the binary tree
115 typedef Traits traits; ///< Traits template parameter
117 # ifdef CDS_DOXYGEN_INVOKED
118 typedef implementation_defined key_comparator; ///< key compare functor based on \p Traits::compare and \p Traits::less
120 typedef typename maker::intrusive_traits::compare key_comparator;
122 typedef typename base_class::item_counter item_counter; ///< Item counting policy
123 typedef typename base_class::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model
124 typedef typename base_class::stat stat; ///< internal statistics type
125 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
126 typedef typename traits::key_extractor key_extractor; ///< key extracting functor
127 typedef typename traits::back_off back_off; ///< Back-off strategy
130 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
131 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
132 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
134 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
138 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
139 typedef typename base_class::value_type leaf_node;
140 typedef typename base_class::internal_node internal_node;
141 typedef std::unique_ptr< leaf_node, typename maker::intrusive_traits::disposer > scoped_node_ptr;
145 typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
147 /// pointer to extracted node
148 using exempt_ptr = cds::urcu::exempt_ptr < gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
149 cds::urcu::details::conventional_exempt_member_cast < leaf_node, value_type >
153 /// Default constructor
164 The function creates a node with copy of \p val value
165 and then inserts the node created into the set.
167 The type \p Q should contain at least the complete key for the node.
168 The object of \ref value_type should be constructible from a value of type \p Q.
169 In trivial case, \p Q is equal to \ref value_type.
171 RCU \p synchronize() method can be called. RCU should not be locked.
173 Returns \p true if \p val is inserted into the set, \p false otherwise.
175 template <typename Q>
176 bool insert( Q const& val )
178 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
179 if ( base_class::insert( *sp.get() )) {
188 The function allows to split creating of new item into two part:
189 - create item with key only
190 - insert new item into the set
191 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
193 The functor signature is:
195 void func( value_type& val );
197 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
198 \p val no any other changes could be made on this set's item by concurrent threads.
199 The user-defined functor is called only if the inserting is success.
201 RCU \p synchronize() can be called. RCU should not be locked.
203 template <typename Q, typename Func>
204 bool insert( Q const& val, Func f )
206 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
207 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
214 /// Ensures that the item exists in the set
216 The operation performs inserting or changing data with lock-free manner.
218 If the \p val key not found in the set, then the new item created from \p val
219 is inserted into the set. Otherwise, the functor \p func is called with the item found.
220 The functor \p Func should be a function with signature:
222 void func( bool bNew, value_type& item, const Q& val );
227 void operator()( bool bNew, value_type& item, const Q& val );
232 - \p bNew - \p true if the item has been inserted, \p false otherwise
233 - \p item - item of the set
234 - \p val - argument \p key passed into the \p ensure function
236 The functor may change non-key fields of the \p item; however, \p func must guarantee
237 that during changing no any other modifications could be made on this item by concurrent threads.
239 RCU \p synchronize() can be called. RCU should not be locked.
241 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
242 \p second is true if new item has been added or \p false if the item with \p key
243 already is in the set.
245 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
247 template <typename Q, typename Func>
248 std::pair<bool, bool> ensure( const Q& val, Func func )
250 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
251 std::pair<bool, bool> bRes = base_class::ensure( *sp,
252 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); });
253 if ( bRes.first && bRes.second )
258 /// Inserts data of type \p value_type created in-place from \p args
260 Returns \p true if inserting successful, \p false otherwise.
262 RCU \p synchronize method can be called. RCU should not be locked.
264 template <typename... Args>
265 bool emplace( Args&&... args )
267 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
268 if ( base_class::insert( *sp.get() )) {
275 /// Delete \p key from the set
276 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_val
278 The item comparator should be able to compare the type \p value_type
281 RCU \p synchronize method can be called. RCU should not be locked.
283 Return \p true if key is found and deleted, \p false otherwise
285 template <typename Q>
286 bool erase( Q const& key )
288 return base_class::erase( key );
291 /// Deletes the item from the set using \p pred predicate for searching
293 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_val "erase(Q const&)"
294 but \p pred is used for key comparing.
295 \p Less functor has the interface like \p std::less.
296 \p Less must imply the same element order as the comparator used for building the set.
298 template <typename Q, typename Less>
299 bool erase_with( Q const& key, Less pred )
302 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
305 /// Delete \p key from the set
306 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_func
308 The function searches an item with key \p key, calls \p f functor
309 and deletes the item. If \p key is not found, the functor is not called.
311 The functor \p Func interface:
314 void operator()(value_type const& val);
318 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
319 template parameter \p Q defines the key type searching in the list.
320 The list item comparator should be able to compare the type \p T of list item
323 RCU \p synchronize method can be called. RCU should not be locked.
325 Return \p true if key is found and deleted, \p false otherwise
329 template <typename Q, typename Func>
330 bool erase( Q const& key, Func f )
332 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
335 /// Deletes the item from the set using \p pred predicate for searching
337 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_func "erase(Q const&, Func)"
338 but \p pred is used for key comparing.
339 \p Less functor has the interface like \p std::less.
340 \p Less must imply the same element order as the comparator used for building the set.
342 template <typename Q, typename Less, typename Func>
343 bool erase_with( Q const& key, Less pred, Func f )
346 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
347 [&f]( leaf_node const& node) { f( node.m_Value ); } );
350 /// Extracts an item with minimal key from the set
352 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
353 If the set is empty, returns empty \p exempt_ptr.
355 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
356 It means that the function gets leftmost leaf of the tree and tries to unlink it.
357 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
358 So, the function returns the item with minimum key at the moment of tree traversing.
360 RCU \p synchronize method can be called. RCU should NOT be locked.
361 The function does not free the item.
362 The deallocator will be implicitly invoked when the returned object is destroyed or when
363 its \p release() member function is called.
365 exempt_ptr extract_min()
367 return exempt_ptr( base_class::extract_min_());
370 /// Extracts an item with maximal key from the set
372 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
373 If the set is empty, returns empty \p exempt_ptr.
375 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
376 It means that the function gets rightmost leaf of the tree and tries to unlink it.
377 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
378 So, the function returns the item with maximum key at the moment of tree traversing.
380 RCU \p synchronize method can be called. RCU should NOT be locked.
381 The function does not free the item.
382 The deallocator will be implicitly invoked when the returned object is destroyed or when
383 its \p release() member function is called.
385 exempt_ptr extract_max()
387 return exempt_ptr( base_class::extract_max_());
390 /// Extracts an item from the set
391 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_extract
392 The function searches an item with key equal to \p key in the tree,
393 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
394 If \p key is not found the function returns an empty \p exempt_ptr.
396 RCU \p synchronize method can be called. RCU should NOT be locked.
397 The function does not destroy the item found.
398 The dealloctor will be implicitly invoked when the returned object is destroyed or when
399 its release() member function is called.
401 template <typename Q>
402 exempt_ptr extract( Q const& key )
404 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
407 /// Extracts an item from the set using \p pred for searching
409 The function is an analog of \p extract(Q const&) but \p pred is used for key compare.
410 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
411 "predicate requirements".
412 \p pred must imply the same element order as the comparator used for building the set.
414 template <typename Q, typename Less>
415 exempt_ptr extract_with( Q const& key, Less pred )
418 return exempt_ptr( base_class::extract_with_( key,
419 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() ));
422 /// Find the key \p key
424 @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_func
426 The function searches the item with key equal to \p key and calls the functor \p f for item found.
427 The interface of \p Func functor is:
430 void operator()( value_type& item, Q& key );
433 where \p item is the item found, \p key is the <tt>find</tt> function argument.
435 The functor may change non-key fields of \p item. Note that the functor is only guarantee
436 that \p item cannot be disposed during functor is executing.
437 The functor does not serialize simultaneous access to the set's \p item. If such access is
438 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
440 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
441 can modify both arguments.
443 Note the hash functor specified for class \p Traits template parameter
444 should accept a parameter of type \p Q that may be not the same as \p value_type.
446 The function applies RCU lock internally.
448 The function returns \p true if \p key is found, \p false otherwise.
450 template <typename Q, typename Func>
451 bool find( Q& key, Func f ) const
453 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
456 template <typename Q, typename Func>
457 bool find( Q const& key, Func f ) const
459 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
463 /// Finds the key \p key using \p pred predicate for searching
465 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_func "find(Q&, Func)"
466 but \p pred is used for key comparing.
467 \p Less functor has the interface like \p std::less.
468 \p Less must imply the same element order as the comparator used for building the set.
470 template <typename Q, typename Less, typename Func>
471 bool find_with( Q& key, Less pred, Func f ) const
474 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
475 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
478 template <typename Q, typename Less, typename Func>
479 bool find_with( Q const& key, Less pred, Func f ) const
482 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
483 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
487 /// Find the key \p key
488 /** @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_val
490 The function searches the item with key equal to \p key
491 and returns \p true if it is found, and \p false otherwise.
493 Note the hash functor specified for class \p Traits template parameter
494 should accept a parameter of type \p Q that may be not the same as \ref value_type.
496 The function applies RCU lock internally.
498 template <typename Q>
499 bool find( Q const& key ) const
501 return base_class::find( key );
504 /// Finds the key \p key using \p pred predicate for searching
506 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_val "find(Q const&)"
507 but \p pred is used for key comparing.
508 \p Less functor has the interface like \p std::less.
509 \p Less must imply the same element order as the comparator used for building the set.
511 template <typename Q, typename Less>
512 bool find_with( Q const& key, Less pred ) const
515 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
518 /// Finds \p key and return the item found
519 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_get
520 The function searches the item with key equal to \p key and returns the pointer to item found.
521 If \p key is not found it returns \p nullptr.
523 RCU should be locked before call the function.
524 Returned pointer is valid while RCU is locked.
526 template <typename Q>
527 value_type * get( Q const& key ) const
529 leaf_node * pNode = base_class::get( key );
530 return pNode ? &pNode->m_Value : nullptr;
533 /// Finds \p key with \p pred predicate and return the item found
535 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_get "get(Q const&)"
536 but \p pred is used for comparing the keys.
538 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
539 and \p Q in any order.
540 \p pred must imply the same element order as the comparator used for building the set.
542 template <typename Q, typename Less>
543 value_type * get_with( Q const& key, Less pred ) const
546 leaf_node * pNode = base_class::get_with( key,
547 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
548 return pNode ? &pNode->m_Value : nullptr;
551 /// Clears the set (non-atomic)
553 The function unlink all items from the tree.
554 The function is not atomic, thus, in multi-threaded environment with parallel insertions
558 assert( set.empty() );
560 the assertion could be raised.
562 For each leaf the \ref disposer will be called after unlinking.
564 RCU \p synchronize method can be called. RCU should not be locked.
571 /// Checks if the set is empty
574 return base_class::empty();
577 /// Returns item count in the set
579 Only leaf nodes containing user data are counted.
581 The value returned depends on item counter type provided by \p Traits template parameter.
582 If it is \p atomicity::empty_item_counter \p %size() always returns 0.
583 Therefore, the function is not suitable for checking the tree emptiness, use \p empty()
584 member function for this purpose.
588 return base_class::size();
591 /// Returns const reference to internal statistics
592 stat const& statistics() const
594 return base_class::statistics();
597 /// Checks internal consistency (not atomic, not thread-safe)
599 The debugging function to check internal consistency of the tree.
601 bool check_consistency() const
603 return base_class::check_consistency();
606 }} // namespace cds::container
608 #endif // #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H