3 #ifndef __CDS_CONTAINER_ELLEN_BINTREE_SET_RCU_H
4 #define __CDS_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
128 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
129 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
130 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
132 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
136 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
137 typedef typename base_class::value_type leaf_node;
138 typedef typename base_class::internal_node internal_node;
139 typedef std::unique_ptr< leaf_node, typename maker::intrusive_traits::disposer > scoped_node_ptr;
143 typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
145 /// pointer to extracted node
146 typedef cds::urcu::exempt_ptr< gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
147 cds::urcu::details::conventional_exempt_member_cast<leaf_node, value_type>
151 /// Default constructor
162 The function creates a node with copy of \p val value
163 and then inserts the node created into the set.
165 The type \p Q should contain at least the complete key for the node.
166 The object of \ref value_type should be constructible from a value of type \p Q.
167 In trivial case, \p Q is equal to \ref value_type.
169 RCU \p synchronize() method can be called. RCU should not be locked.
171 Returns \p true if \p val is inserted into the set, \p false otherwise.
173 template <typename Q>
174 bool insert( Q const& val )
176 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
177 if ( base_class::insert( *sp.get() )) {
186 The function allows to split creating of new item into two part:
187 - create item with key only
188 - insert new item into the set
189 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
191 The functor signature is:
193 void func( value_type& val );
195 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
196 \p val no any other changes could be made on this set's item by concurrent threads.
197 The user-defined functor is called only if the inserting is success.
199 RCU \p synchronize() can be called. RCU should not be locked.
201 template <typename Q, typename Func>
202 bool insert( Q const& val, Func f )
204 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
205 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
212 /// Ensures that the item exists in the set
214 The operation performs inserting or changing data with lock-free manner.
216 If the \p val key not found in the set, then the new item created from \p val
217 is inserted into the set. Otherwise, the functor \p func is called with the item found.
218 The functor \p Func should be a function with signature:
220 void func( bool bNew, value_type& item, const Q& val );
225 void operator()( bool bNew, value_type& item, const Q& val );
230 - \p bNew - \p true if the item has been inserted, \p false otherwise
231 - \p item - item of the set
232 - \p val - argument \p key passed into the \p ensure function
234 The functor may change non-key fields of the \p item; however, \p func must guarantee
235 that during changing no any other modifications could be made on this item by concurrent threads.
237 RCU \p synchronize() can be called. RCU should not be locked.
239 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
240 \p second is true if new item has been added or \p false if the item with \p key
241 already is in the set.
243 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
245 template <typename Q, typename Func>
246 std::pair<bool, bool> ensure( const Q& val, Func func )
248 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
249 std::pair<bool, bool> bRes = base_class::ensure( *sp,
250 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); });
251 if ( bRes.first && bRes.second )
256 /// Inserts data of type \p value_type created in-place from \p args
258 Returns \p true if inserting successful, \p false otherwise.
260 RCU \p synchronize method can be called. RCU should not be locked.
262 template <typename... Args>
263 bool emplace( Args&&... args )
265 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
266 if ( base_class::insert( *sp.get() )) {
273 /// Delete \p key from the set
274 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_val
276 The item comparator should be able to compare the type \p value_type
279 RCU \p synchronize method can be called. RCU should not be locked.
281 Return \p true if key is found and deleted, \p false otherwise
283 template <typename Q>
284 bool erase( Q const& key )
286 return base_class::erase( key );
289 /// Deletes the item from the set using \p pred predicate for searching
291 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_val "erase(Q const&)"
292 but \p pred is used for key comparing.
293 \p Less functor has the interface like \p std::less.
294 \p Less must imply the same element order as the comparator used for building the set.
296 template <typename Q, typename Less>
297 bool erase_with( Q const& key, Less pred )
299 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
302 /// Delete \p key from the set
303 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_func
305 The function searches an item with key \p key, calls \p f functor
306 and deletes the item. If \p key is not found, the functor is not called.
308 The functor \p Func interface:
311 void operator()(value_type const& val);
315 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
316 template parameter \p Q defines the key type searching in the list.
317 The list item comparator should be able to compare the type \p T of list item
320 RCU \p synchronize method can be called. RCU should not be locked.
322 Return \p true if key is found and deleted, \p false otherwise
326 template <typename Q, typename Func>
327 bool erase( Q const& key, Func f )
329 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
332 /// Deletes the item from the set using \p pred predicate for searching
334 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_func "erase(Q const&, Func)"
335 but \p pred is used for key comparing.
336 \p Less functor has the interface like \p std::less.
337 \p Less must imply the same element order as the comparator used for building the set.
339 template <typename Q, typename Less, typename Func>
340 bool erase_with( Q const& key, Less pred, Func f )
342 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
343 [&f]( leaf_node const& node) { f( node.m_Value ); } );
346 /// Extracts an item with minimal key from the set
348 If the set is not empty, the function returns \p true, \p result contains a pointer to value.
349 If the set is empty, the function returns \p false, \p result is left unchanged.
351 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
352 It means that the function gets leftmost leaf of the tree and tries to unlink it.
353 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
354 So, the function returns the item with minimum key at the moment of tree traversing.
356 RCU \p synchronize method can be called. RCU should NOT be locked.
357 The function does not free the item.
358 The deallocator will be implicitly invoked when \p result object is destroyed or when
359 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
360 @note Before reusing \p result object you should call its \p release() method.
362 bool extract_min( exempt_ptr& result )
364 return base_class::extract_min_( result );
367 /// Extracts an item with maximal key from the set
369 If the set is not empty, the function returns \p true, \p result contains a pointer to extracted item.
370 If the set is empty, the function returns \p false, \p result is left unchanged.
372 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
373 It means that the function gets rightmost leaf of the tree and tries to unlink it.
374 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
375 So, the function returns the item with maximum key at the moment of tree traversing.
377 RCU \p synchronize method can be called. RCU should NOT be locked.
378 The function does not free the item.
379 The deallocator will be implicitly invoked when \p result object is destroyed or when
380 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
381 @note Before reusing \p result object you should call its \p release() method.
383 bool extract_max( exempt_ptr& result )
385 return base_class::extract_max_( result );
388 /// Extracts an item from the set
389 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_extract
390 The function searches an item with key equal to \p key in the tree,
391 unlinks it, and returns pointer to an item found in \p result parameter.
392 If \p key is not found the function returns \p false.
394 RCU \p synchronize method can be called. RCU should NOT be locked.
395 The function does not destroy the item found.
396 The dealloctor will be implicitly invoked when \p result object is destroyed or when
397 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
398 @note Before reusing \p result object you should call its \p release() method.
400 template <typename Q>
401 bool extract( exempt_ptr& result, Q const& key )
403 return base_class::extract_( result, key, typename base_class::node_compare());
406 /// Extracts an item from the set using \p pred for searching
408 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_extract "extract(exempt_ptr&, Q const&)"
409 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 bool extract_with( exempt_ptr& result, Q const& val, Less pred )
417 return base_class::extract_with_( result, val,
418 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() );
421 /// Find the key \p key
423 @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_func
425 The function searches the item with key equal to \p key and calls the functor \p f for item found.
426 The interface of \p Func functor is:
429 void operator()( value_type& item, Q& key );
432 where \p item is the item found, \p key is the <tt>find</tt> function argument.
434 The functor may change non-key fields of \p item. Note that the functor is only guarantee
435 that \p item cannot be disposed during functor is executing.
436 The functor does not serialize simultaneous access to the set's \p item. If such access is
437 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
439 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
440 can modify both arguments.
442 Note the hash functor specified for class \p Traits template parameter
443 should accept a parameter of type \p Q that may be not the same as \p value_type.
445 The function applies RCU lock internally.
447 The function returns \p true if \p key is found, \p false otherwise.
449 template <typename Q, typename Func>
450 bool find( Q& key, Func f ) const
452 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
455 template <typename Q, typename Func>
456 bool find( Q const& key, Func f ) const
458 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
462 /// Finds the key \p key using \p pred predicate for searching
464 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_func "find(Q&, Func)"
465 but \p pred is used for key comparing.
466 \p Less functor has the interface like \p std::less.
467 \p Less must imply the same element order as the comparator used for building the set.
469 template <typename Q, typename Less, typename Func>
470 bool find_with( Q& key, Less pred, Func f ) const
472 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
473 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
476 template <typename Q, typename Less, typename Func>
477 bool find_with( Q const& key, Less pred, Func f ) const
479 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
480 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
484 /// Find the key \p key
485 /** @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_val
487 The function searches the item with key equal to \p key
488 and returns \p true if it is found, and \p false otherwise.
490 Note the hash functor specified for class \p Traits template parameter
491 should accept a parameter of type \p Q that may be not the same as \ref value_type.
493 The function applies RCU lock internally.
495 template <typename Q>
496 bool find( Q const& key ) const
498 return base_class::find( key );
501 /// Finds the key \p key using \p pred predicate for searching
503 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_val "find(Q const&)"
504 but \p pred is used for key comparing.
505 \p Less functor has the interface like \p std::less.
506 \p Less must imply the same element order as the comparator used for building the set.
508 template <typename Q, typename Less>
509 bool find_with( Q const& key, Less pred ) const
511 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
514 /// Finds \p key and return the item found
515 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_get
516 The function searches the item with key equal to \p key and returns the pointer to item found.
517 If \p key is not found it returns \p nullptr.
519 RCU should be locked before call the function.
520 Returned pointer is valid while RCU is locked.
522 template <typename Q>
523 value_type * get( Q const& key ) const
525 leaf_node * pNode = base_class::get( key );
526 return pNode ? &pNode->m_Value : nullptr;
529 /// Finds \p key with \p pred predicate and return the item found
531 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_get "get(Q const&)"
532 but \p pred is used for comparing the keys.
534 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
535 and \p Q in any order.
536 \p pred must imply the same element order as the comparator used for building the set.
538 template <typename Q, typename Less>
539 value_type * get_with( Q const& key, Less pred ) const
541 leaf_node * pNode = base_class::get_with( key,
542 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
543 return pNode ? &pNode->m_Value : nullptr;
546 /// Clears the set (non-atomic)
548 The function unlink all items from the tree.
549 The function is not atomic, thus, in multi-threaded environment with parallel insertions
553 assert( set.empty() );
555 the assertion could be raised.
557 For each leaf the \ref disposer will be called after unlinking.
559 RCU \p synchronize method can be called. RCU should not be locked.
566 /// Checks if the set is empty
569 return base_class::empty();
572 /// Returns item count in the set
574 Only leaf nodes containing user data are counted.
576 The value returned depends on item counter type provided by \p Traits template parameter.
577 If it is \p atomicity::empty_item_counter \p %size() always returns 0.
578 Therefore, the function is not suitable for checking the tree emptiness, use \p empty()
579 member function for this purpose.
583 return base_class::size();
586 /// Returns const reference to internal statistics
587 stat const& statistics() const
589 return base_class::statistics();
592 /// Checks internal consistency (not atomic, not thread-safe)
594 The debugging function to check internal consistency of the tree.
596 bool check_consistency() const
598 return base_class::check_consistency();
601 }} // namespace cds::container
603 #endif // #ifndef __CDS_CONTAINER_ELLEN_BINTREE_SET_RCU_H