3 #ifndef CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H
4 #define CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H
7 #include <cds/container/details/ellen_bintree_base.h>
8 #include <cds/intrusive/impl/ellen_bintree.h>
9 #include <cds/container/details/guarded_ptr_cast.h>
11 namespace cds { namespace container {
13 /// Set based on Ellen's et al binary search tree
14 /** @ingroup cds_nonintrusive_set
15 @ingroup cds_nonintrusive_tree
16 @anchor cds_container_EllenBinTreeSet
19 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
21 %EllenBinTreeSet is an unbalanced leaf-oriented binary search tree that implements the <i>set</i>
22 abstract data type. Nodes maintains child pointers but not parent pointers.
23 Every internal node has exactly two children, and all data of type \p T currently in
24 the tree are stored in the leaves. Internal nodes of the tree are used to direct \p find
25 operation along the path to the correct leaf. The keys (of \p Key type) stored in internal nodes
26 may or may not be in the set. \p Key type is a subset of \p T type.
27 There should be exactly defined a key extracting functor for converting object of type \p T to
28 object of type \p Key.
30 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeSet can act as
31 a <i>priority queue</i>. In this case you should provide unique compound key, for example,
32 the priority value plus some uniformly distributed random value.
34 @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
35 for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
37 @note In the current implementation we do not use helping technique described in the original paper.
38 In Hazard Pointer schema helping is too complicated and does not give any observable benefits.
39 Instead of helping, when a thread encounters a concurrent operation it just spins waiting for
40 the operation done. Such solution allows greatly simplify the implementation of tree.
42 <b>Template arguments</b> :
43 - \p GC - safe memory reclamation (i.e. light-weight garbage collector) type, like \p cds::gc::HP, cds::gc::DHP
44 - \p Key - key type, a subset of \p T
45 - \p T - type to be stored in tree's leaf nodes.
46 - \p Traits - set traits, default is \p ellen_bintree::traits
47 It is possible to declare option-based tree with \p ellen_bintree::make_set_traits metafunction
48 instead of \p Traits template argument.
50 @note Do not include <tt><cds/container/impl/ellen_bintree_set.h></tt> header file directly.
51 There are header file for each GC type:
52 - <tt><cds/container/ellen_bintree_set_hp.h></tt> - for \p cds::gc::HP
53 - <tt><cds/container/ellen_bintree_set_dhp.h></tt> - for \p cds::gc::DHP
54 - <tt><cds/container/ellen_bintree_set_rcu.h></tt> - for RCU GC
55 (see \ref cds_container_EllenBinTreeSet_rcu "RCU-based EllenBinTreeSet")
57 @anchor cds_container_EllenBinTreeSet_less
58 <b>Predicate requirements</b>
60 \p Traits::less, \p Traits::compare and other predicates using with member fuctions should accept at least parameters
61 of type \p T and \p Key in any combination.
62 For example, for \p Foo struct with \p std::string key field the appropiate \p less functor is:
71 bool operator()( Foo const& v1, Foo const& v2 ) const
72 { return v1.m_strKey < v2.m_strKey ; }
74 bool operator()( Foo const& v, std::string const& s ) const
75 { return v.m_strKey < s ; }
77 bool operator()( std::string const& s, Foo const& v ) const
78 { return s < v.m_strKey ; }
80 // Support comparing std::string and char const *
81 bool operator()( std::string const& s, char const * p ) const
82 { return s.compare(p) < 0 ; }
84 bool operator()( Foo const& v, char const * p ) const
85 { return v.m_strKey.compare(p) < 0 ; }
87 bool operator()( char const * p, std::string const& s ) const
88 { return s.compare(p) > 0; }
90 bool operator()( char const * p, Foo const& v ) const
91 { return v.m_strKey.compare(p) > 0; }
99 #ifdef CDS_DOXYGEN_INVOKED
100 class Traits = ellen_bintree::traits
105 class EllenBinTreeSet
106 #ifdef CDS_DOXYGEN_INVOKED
107 : public cds::intrusive::EllenBinTree< GC, Key, T, Traits >
109 : public ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits >::type
113 typedef ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits > maker;
114 typedef typename maker::type base_class;
118 typedef GC gc; ///< Garbage collector
119 typedef Key key_type; ///< type of a key to be stored in internal nodes; key is a part of \p value_type
120 typedef T value_type; ///< type of value to be stored in the binary tree
121 typedef Traits traits; ///< Traits template parameter
123 # ifdef CDS_DOXYGEN_INVOKED
124 typedef implementation_defined key_comparator ; ///< key compare functor based on opt::compare and opt::less option setter.
126 typedef typename maker::intrusive_traits::compare key_comparator;
128 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
129 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
130 typedef typename base_class::stat stat; ///< internal statistics type
131 typedef typename traits::key_extractor key_extractor; ///< key extracting functor
132 typedef typename traits::back_off back_off; ///< Back-off strategy
134 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
135 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
136 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
139 typedef cds::container::ellen_bintree::implementation_tag implementation_tag;
144 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
145 typedef typename base_class::value_type leaf_node;
146 typedef typename base_class::internal_node internal_node;
148 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
153 typedef typename gc::template guarded_ptr< leaf_node, value_type, details::guarded_ptr_cast_set<leaf_node, value_type> > guarded_ptr;
156 /// Default constructor
167 The function creates a node with copy of \p val value
168 and then inserts the node created into the set.
170 The type \p Q should contain at least the complete key for the node.
171 The object of \ref value_type should be constructible from a value of type \p Q.
172 In trivial case, \p Q is equal to \ref value_type.
174 Returns \p true if \p val is inserted into the set, \p false otherwise.
176 template <typename Q>
177 bool insert( Q const& val )
179 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
180 if ( base_class::insert( *sp.get() )) {
189 The function allows to split creating of new item into two part:
190 - create item with key only
191 - insert new item into the set
192 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
194 The functor signature is:
196 void func( value_type& val );
198 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
199 \p val no any other changes could be made on this set's item by concurrent threads.
200 The user-defined functor is called only if the inserting is success.
202 template <typename Q, typename Func>
203 bool insert( Q const& val, Func f )
205 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
206 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
215 The operation performs inserting or changing data with lock-free manner.
217 If the item \p val is not found in the set, then \p val is inserted into the set
218 iff \p bAllowInsert is \p true.
219 Otherwise, the functor \p func is called with item found.
220 The functor \p func signature is:
223 void operator()( bool bNew, value_type& item, const Q& val );
228 - \p bNew - \p true if the item has been inserted, \p false otherwise
229 - \p item - item of the set
230 - \p val - argument \p key passed into the \p %update() function
232 The functor can change non-key fields of the \p item; however, \p func must guarantee
233 that during changing no any other modifications could be made on this item by concurrent threads.
235 Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
236 i.e. the node has been inserted or updated,
237 \p second is \p true if new item has been added or \p false if the item with \p key
240 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
242 template <typename Q, typename Func>
243 std::pair<bool, bool> update( const Q& val, Func func, bool bAllowInsert = true )
245 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
246 std::pair<bool, bool> bRes = base_class::update( *sp,
247 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); },
249 if ( bRes.first && bRes.second )
254 // Deprecated, use update()
255 template <typename Q, typename Func>
256 std::pair<bool, bool> ensure( const Q& val, Func func )
258 return update( val, func, true );
262 /// Inserts data of type \p value_type created in-place from \p args
264 Returns \p true if inserting successful, \p false otherwise.
266 template <typename... Args>
267 bool emplace( Args&&... args )
269 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
270 if ( base_class::insert( *sp.get() )) {
277 /// Delete \p key from the set
278 /** \anchor cds_nonintrusive_EllenBinTreeSet_erase_val
280 The item comparator should be able to compare the type \p value_type
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_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_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 Return \p true if key is found and deleted, \p false otherwise
325 template <typename Q, typename Func>
326 bool erase( Q const& key, Func f )
328 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
331 /// Deletes the item from the set using \p pred predicate for searching
333 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_erase_func "erase(Q const&, Func)"
334 but \p pred is used for key comparing.
335 \p Less functor has the interface like \p std::less.
336 \p Less must imply the same element order as the comparator used for building the set.
338 template <typename Q, typename Less, typename Func>
339 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 a guarded pointer to minimum value.
349 If the set is empty, the function returns an empty \p guarded_ptr.
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 The guarded pointer prevents deallocation of returned item,
357 see \p cds::gc::guarded_ptr for explanation.
358 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
360 guarded_ptr extract_min()
363 base_class::extract_min_( gp.guard() );
367 /// Extracts an item with maximal key from the set
369 If the set is not empty, the function returns a guarded pointer to maximal value.
370 If the set is empty, the function returns an empty \p guarded_ptr.
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 The guarded pointer prevents deallocation of returned item,
378 see \p cds::gc::guarded_ptr for explanation.
379 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
381 guarded_ptr extract_max()
384 base_class::extract_max_( gp.guard() );
388 /// Extracts an item from the tree
389 /** \anchor cds_nonintrusive_EllenBinTreeSet_extract
390 The function searches an item with key equal to \p key in the tree,
391 unlinks it, and returns an guarded pointer to it.
392 If the item is not found the function returns an empty \p guarded_ptr.
394 The guarded pointer prevents deallocation of returned item,
395 see \p cds::gc::guarded_ptr for explanation.
396 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
398 template <typename Q>
399 guarded_ptr extract( Q const& key )
402 base_class::extract_( gp.guard(), key );
406 /// Extracts an item from the set using \p pred for searching
408 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_extract "extract(Q const&)"
409 but \p pred is used for key compare.
410 \p Less has the interface like \p std::less.
411 \p pred must imply the same element order as the comparator used for building the set.
413 template <typename Q, typename Less>
414 guarded_ptr extract_with( Q const& key, Less pred )
418 base_class::extract_with_( gp.guard(), key,
419 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
423 /// Find the key \p key
425 @anchor cds_nonintrusive_EllenBinTreeSet_find_func
427 The function searches the item with key equal to \p key and calls the functor \p f for item found.
428 The interface of \p Func functor is:
431 void operator()( value_type& item, Q& key );
434 where \p item is the item found, \p key is the <tt>find</tt> function argument.
436 The functor may change non-key fields of \p item. Note that the functor is only guarantee
437 that \p item cannot be disposed during functor is executing.
438 The functor does not serialize simultaneous access to the set's \p item. If such access is
439 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
441 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
442 can modify both arguments.
444 Note the hash functor specified for class \p Traits template parameter
445 should accept a parameter of type \p Q that may be not the same as \p value_type.
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 )
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 )
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_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 )
473 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
474 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
477 template <typename Q, typename Less, typename Func>
478 bool find_with( Q const& key, Less pred, Func f )
481 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
482 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
486 /// Checks whether the set contains \p key
488 The function searches the item with key equal to \p key
489 and returns \p true if it is found, and \p false otherwise.
491 template <typename Q>
492 bool contains( Q const & key )
494 return base_class::contains( key );
497 // Deprecated, use contains()
498 template <typename Q>
499 bool find( Q const & key )
501 return contains( key );
505 /// Checks whether the set contains \p key using \p pred predicate for searching
507 The function is similar to <tt>contains( key )</tt> 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 contains( Q const& key, Less pred )
515 return base_class::contains( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
518 // Deprecated, use contains()
519 template <typename Q, typename Less>
520 bool find_with( Q const& key, Less pred )
522 return contains( key, pred );
526 /// Finds \p key and returns the item found
527 /** @anchor cds_nonintrusive_EllenBinTreeSet_get
528 The function searches the item with key equal to \p key and returns the item found as an guarded pointer.
529 The function returns \p true if \p key is found, \p false otherwise.
531 The guarded pointer prevents deallocation of returned item,
532 see \p cds::gc::guarded_ptr for explanation.
533 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
535 template <typename Q>
536 guarded_ptr get( Q const& key )
539 base_class::get_( gp.guard(), key );
543 /// Finds \p key with predicate \p pred and returns the item found
545 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_get "get(Q const&)"
546 but \p pred is used for key comparing.
547 \p Less functor has the interface like \p std::less.
548 \p pred must imply the same element order as the comparator used for building the set.
550 template <typename Q, typename Less>
551 guarded_ptr get_with( Q const& key, Less pred )
555 base_class::get_with_( gp.guard(), key,
556 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() );
560 /// Clears the set (not atomic)
562 The function unlink all items from the tree.
563 The function is not atomic, thus, in multi-threaded environment with parallel insertions
567 assert( set.empty() );
569 the assertion could be raised.
571 For each leaf the \ref disposer will be called after unlinking.
578 /// Checks if the set is empty
581 return base_class::empty();
584 /// Returns item count in the set
586 Only leaf nodes containing user data are counted.
588 The value returned depends on item counter type provided by \p Traits template parameter.
589 If it is \p atomicity::empty_item_counter this function always returns 0.
591 The function is not suitable for checking the tree emptiness, use \p empty()
592 member function for this purpose.
596 return base_class::size();
599 /// Returns const reference to internal statistics
600 stat const& statistics() const
602 return base_class::statistics();
605 /// Checks internal consistency (not atomic, not thread-safe)
607 The debugging function to check internal consistency of the tree.
609 bool check_consistency() const
611 return base_class::check_consistency();
615 }} // namespace cds::container
617 #endif // #ifndef CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H