3 #ifndef __CDS_CONTAINER_IMPL_ELLEN_BINTREE_SET_H
4 #define __CDS_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 original paper.
38 So, the current implementation is near to fine-grained lock-based tree.
39 Helping will be implemented in future release
41 <b>Template arguments</b> :
42 - \p GC - safe memory reclamation (i.e. light-weight garbage collector) type, like \p cds::gc::HP, cds::gc::DHP
43 - \p Key - key type, a subset of \p T
44 - \p T - type to be stored in tree's leaf nodes.
45 - \p Traits - set traits, default is \p ellen_bintree::traits
46 It is possible to declare option-based tree with \p ellen_bintree::make_set_traits metafunction
47 instead of \p Traits template argument.
49 @note Do not include <tt><cds/container/impl/ellen_bintree_set.h></tt> header file directly.
50 There are header file for each GC type:
51 - <tt><cds/container/ellen_bintree_set_hp.h></tt> - for \p cds::gc::HP
52 - <tt><cds/container/ellen_bintree_set_ptb.h></tt> - for \p cds::gc::DHP
53 - <tt><cds/container/ellen_bintree_set_rcu.h></tt> - for RCU GC
54 (see \ref cds_container_EllenBinTreeSet_rcu "RCU-based EllenBinTreeSet")
56 @anchor cds_container_EllenBinTreeSet_less
57 <b>Predicate requirements</b>
59 \p Traits::less, \p Traits::compare and other predicates using with member fuctions should accept at least parameters
60 of type \p T and \p Key in any combination.
61 For example, for \p Foo struct with \p std::string key field the appropiate \p less functor is:
70 bool operator()( Foo const& v1, Foo const& v2 ) const
71 { return v1.m_strKey < v2.m_strKey ; }
73 bool operator()( Foo const& v, std::string const& s ) const
74 { return v.m_strKey < s ; }
76 bool operator()( std::string const& s, Foo const& v ) const
77 { return s < v.m_strKey ; }
79 // Support comparing std::string and char const *
80 bool operator()( std::string const& s, char const * p ) const
81 { return s.compare(p) < 0 ; }
83 bool operator()( Foo const& v, char const * p ) const
84 { return v.m_strKey.compare(p) < 0 ; }
86 bool operator()( char const * p, std::string const& s ) const
87 { return s.compare(p) > 0; }
89 bool operator()( char const * p, Foo const& v ) const
90 { return v.m_strKey.compare(p) > 0; }
98 #ifdef CDS_DOXYGEN_INVOKED
99 class Traits = ellen_bintree::traits
104 class EllenBinTreeSet
105 #ifdef CDS_DOXYGEN_INVOKED
106 : public cds::intrusive::EllenBinTree< GC, Key, T, Traits >
108 : public ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits >::type
112 typedef ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits > maker;
113 typedef typename maker::type base_class;
117 typedef GC gc; ///< Garbage collector
118 typedef Key key_type; ///< type of a key to be stored in internal nodes; key is a part of \p value_type
119 typedef T value_type; ///< type of value to be stored in the binary tree
120 typedef Traits traits; ///< Traits template parameter
122 # ifdef CDS_DOXYGEN_INVOKED
123 typedef implementation_defined key_comparator ; ///< key compare functor based on opt::compare and opt::less option setter.
125 typedef typename maker::intrusive_type_traits::compare key_comparator;
127 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
128 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
129 typedef typename base_class::stat stat; ///< internal statistics type
130 typedef typename traits::key_extractor key_extractor; ///< key extracting functor
132 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
133 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
134 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
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;
142 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
147 typedef cds::gc::guarded_ptr< gc, leaf_node, value_type, details::guarded_ptr_cast_set<leaf_node, value_type> > guarded_ptr;
150 /// Default constructor
161 The function creates a node with copy of \p val value
162 and then inserts the node created into the set.
164 The type \p Q should contain at least the complete key for the node.
165 The object of \ref value_type should be constructible from a value of type \p Q.
166 In trivial case, \p Q is equal to \ref value_type.
168 Returns \p true if \p val is inserted into the set, \p false otherwise.
170 template <typename Q>
171 bool insert( Q const& val )
173 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
174 if ( base_class::insert( *sp.get() )) {
183 The function allows to split creating of new item into two part:
184 - create item with key only
185 - insert new item into the set
186 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
188 The functor signature is:
190 void func( value_type& val );
192 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
193 \p val no any other changes could be made on this set's item by concurrent threads.
194 The user-defined functor is called only if the inserting is success.
196 template <typename Q, typename Func>
197 bool insert( Q const& val, Func f )
199 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
200 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
207 /// Ensures that the item exists in the set
209 The operation performs inserting or changing data with lock-free manner.
211 If the \p val key not found in the set, then the new item created from \p val
212 is inserted into the set. Otherwise, the functor \p func is called with the item found.
213 The functor \p Func should be a function with signature:
215 void func( bool bNew, value_type& item, const Q& val );
220 void operator()( bool bNew, value_type& item, const Q& val );
225 - \p bNew - \p true if the item has been inserted, \p false otherwise
226 - \p item - item of the set
227 - \p val - argument \p key passed into the \p ensure function
229 The functor may change non-key fields of the \p item; however, \p func must guarantee
230 that during changing no any other modifications could be made on this item by concurrent threads.
232 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
233 \p second is true if new item has been added or \p false if the item with \p key
234 already is in the set.
236 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
238 template <typename Q, typename Func>
239 std::pair<bool, bool> ensure( const Q& val, Func func )
241 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
242 std::pair<bool, bool> bRes = base_class::ensure( *sp,
243 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); });
244 if ( bRes.first && bRes.second )
249 /// Inserts data of type \p value_type created in-place from \p args
251 Returns \p true if inserting successful, \p false otherwise.
253 template <typename... Args>
254 bool emplace( Args&&... args )
256 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
257 if ( base_class::insert( *sp.get() )) {
264 /// Delete \p key from the set
265 /** \anchor cds_nonintrusive_EllenBinTreeSet_erase_val
267 The item comparator should be able to compare the type \p value_type
270 Return \p true if key is found and deleted, \p false otherwise
272 template <typename Q>
273 bool erase( Q const& key )
275 return base_class::erase( key );
278 /// Deletes the item from the set using \p pred predicate for searching
280 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_erase_val "erase(Q const&)"
281 but \p pred is used for key comparing.
282 \p Less functor has the interface like \p std::less.
283 \p Less must imply the same element order as the comparator used for building the set.
285 template <typename Q, typename Less>
286 bool erase_with( Q const& key, Less pred )
288 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
291 /// Delete \p key from the set
292 /** \anchor cds_nonintrusive_EllenBinTreeSet_erase_func
294 The function searches an item with key \p key, calls \p f functor
295 and deletes the item. If \p key is not found, the functor is not called.
297 The functor \p Func interface:
300 void operator()(value_type const& val);
304 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
305 template parameter \p Q defines the key type searching in the list.
306 The list item comparator should be able to compare the type \p T of list item
309 Return \p true if key is found and deleted, \p false otherwise
311 template <typename Q, typename Func>
312 bool erase( Q const& key, Func f )
314 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
317 /// Deletes the item from the set using \p pred predicate for searching
319 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_erase_func "erase(Q const&, Func)"
320 but \p pred is used for key comparing.
321 \p Less functor has the interface like \p std::less.
322 \p Less must imply the same element order as the comparator used for building the set.
324 template <typename Q, typename Less, typename Func>
325 bool erase_with( Q const& key, Less pred, Func f )
327 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
328 [&f]( leaf_node const& node) { f( node.m_Value ); } );
331 /// Extracts an item with minimal key from the set
333 If the set is not empty, the function returns \p true, \p result contains a pointer to minimum value.
334 If the set is empty, the function returns \p false, \p result is left unchanged.
336 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
337 It means that the function gets leftmost leaf of the tree and tries to unlink it.
338 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
339 So, the function returns the item with minimum key at the moment of tree traversing.
341 The guarded pointer \p dest prevents deallocation of returned item,
342 see cds::gc::guarded_ptr for explanation.
343 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
345 bool extract_min( guarded_ptr& result )
347 return base_class::extract_min_( result.guard() );
350 /// Extracts an item with maximal key from the set
352 If the set is not empty, the function returns \p true, \p result contains a pointer to maximal value.
353 If the set is empty, the function returns \p false, \p result is left unchanged.
355 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
356 It means that the function gets rightmost leaf of the tree and tries to unlink it.
357 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
358 So, the function returns the item with maximum key at the moment of tree traversing.
360 The guarded pointer \p dest prevents deallocation of returned item,
361 see cds::gc::guarded_ptr for explanation.
362 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
364 bool extract_max( guarded_ptr& result )
366 return base_class::extract_max_( result.guard() );
369 /// Extracts an item from the tree
370 /** \anchor cds_nonintrusive_EllenBinTreeSet_extract
371 The function searches an item with key equal to \p key in the tree,
372 unlinks it, and returns pointer to an item found in \p result parameter.
373 If the item is not found the function returns \p false.
375 The guarded pointer \p dest prevents deallocation of returned item,
376 see cds::gc::guarded_ptr for explanation.
377 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
379 template <typename Q>
380 bool extract( guarded_ptr& result, Q const& key )
382 return base_class::extract_( result.guard(), key );
385 /// Extracts an item from the set using \p pred for searching
387 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_extract "extract(guarded_ptr& dest, Q const&)"
388 but \p pred is used for key compare.
389 \p Less has the interface like \p std::less.
390 \p pred must imply the same element order as the comparator used for building the set.
392 template <typename Q, typename Less>
393 bool extract_with( guarded_ptr& result, Q const& key, Less pred )
395 return base_class::extract_with_( result.guard(), key,
396 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
399 /// Find the key \p key
401 @anchor cds_nonintrusive_EllenBinTreeSet_find_func
403 The function searches the item with key equal to \p key and calls the functor \p f for item found.
404 The interface of \p Func functor is:
407 void operator()( value_type& item, Q& key );
410 where \p item is the item found, \p key is the <tt>find</tt> function argument.
412 You may pass \p f argument by reference using \p std::ref.
414 The functor may change non-key fields of \p item. Note that the functor is only guarantee
415 that \p item cannot be disposed during functor is executing.
416 The functor does not serialize simultaneous access to the set's \p item. If such access is
417 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
419 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
420 can modify both arguments.
422 Note the hash functor specified for class \p Traits template parameter
423 should accept a parameter of type \p Q that may be not the same as \p value_type.
425 The function returns \p true if \p key is found, \p false otherwise.
427 template <typename Q, typename Func>
428 bool find( Q& key, Func f )
430 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
433 template <typename Q, typename Func>
434 bool find( Q const& key, Func f )
436 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
440 /// Finds the key \p key using \p pred predicate for searching
442 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_find_func "find(Q&, Func)"
443 but \p pred is used for key comparing.
444 \p Less functor has the interface like \p std::less.
445 \p Less must imply the same element order as the comparator used for building the set.
447 template <typename Q, typename Less, typename Func>
448 bool find_with( Q& key, Less pred, Func f )
450 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
451 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
454 template <typename Q, typename Less, typename Func>
455 bool find_with( Q const& key, Less pred, Func f )
457 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
458 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
462 /// Find the key \p key
463 /** @anchor cds_nonintrusive_EllenBinTreeSet_find_val
465 The function searches the item with key equal to \p key
466 and returns \p true if it is found, and \p false otherwise.
468 Note the hash functor specified for class \p Traits template parameter
469 should accept a parameter of type \p Q that may be not the same as \ref value_type.
471 template <typename Q>
472 bool find( Q const & key )
474 return base_class::find( key );
477 /// Finds the key \p key using \p pred predicate for searching
479 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_find_val "find(Q const&)"
480 but \p pred is used for key comparing.
481 \p Less functor has the interface like \p std::less.
482 \p Less must imply the same element order as the comparator used for building the set.
484 template <typename Q, typename Less>
485 bool find_with( Q const& key, Less pred )
487 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
490 /// Finds \p key and returns the item found
491 /** @anchor cds_nonintrusive_EllenBinTreeSet_get
492 The function searches the item with key equal to \p key and returns the item found in \p result parameter.
493 The function returns \p true if \p key is found, \p false otherwise.
495 The guarded pointer \p dest prevents deallocation of returned item,
496 see cds::gc::guarded_ptr for explanation.
497 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
499 template <typename Q>
500 bool get( guarded_ptr& result, Q const& key )
502 return base_class::get_( result.guard(), key );
505 /// Finds \p key with predicate \p pred and returns the item found
507 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_get "get(guarded_ptr&, Q const&)"
508 but \p pred is used for key comparing.
509 \p Less functor has the interface like \p std::less.
510 \p pred must imply the same element order as the comparator used for building the set.
512 template <typename Q, typename Less>
513 bool get_with( guarded_ptr& result, Q const& key, Less pred )
515 return base_class::get_with_( result.guard(), key,
516 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() );
519 /// Clears the set (not atomic)
521 The function unlink all items from the tree.
522 The function is not atomic, thus, in multi-threaded environment with parallel insertions
526 assert( set.empty() );
528 the assertion could be raised.
530 For each leaf the \ref disposer will be called after unlinking.
537 /// Checks if the set is empty
540 return base_class::empty();
543 /// Returns item count in the set
545 Only leaf nodes containing user data are counted.
547 The value returned depends on item counter type provided by \p Traits template parameter.
548 If it is \p atomicity::empty_item_counter this function always returns 0.
550 The function is not suitable for checking the tree emptiness, use \p empty()
551 member function for this purpose.
555 return base_class::size();
558 /// Returns const reference to internal statistics
559 stat const& statistics() const
561 return base_class::statistics();
564 /// Checks internal consistency (not atomic, not thread-safe)
566 The debugging function to check internal consistency of the tree.
568 bool check_consistency() const
570 return base_class::check_consistency();
574 }} // namespace cds::container
576 #endif // #ifndef __CDS_CONTAINER_IMPL_ELLEN_BINTREE_SET_H