2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
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31 #ifndef CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H
32 #define CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H
34 #include <type_traits>
35 #include <cds/container/details/ellen_bintree_base.h>
36 #include <cds/intrusive/impl/ellen_bintree.h>
37 #include <cds/container/details/guarded_ptr_cast.h>
39 namespace cds { namespace container {
41 /// Set based on Ellen's et al binary search tree
42 /** @ingroup cds_nonintrusive_set
43 @ingroup cds_nonintrusive_tree
44 @anchor cds_container_EllenBinTreeSet
47 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
49 %EllenBinTreeSet is an unbalanced leaf-oriented binary search tree that implements the <i>set</i>
50 abstract data type. Nodes maintains child pointers but not parent pointers.
51 Every internal node has exactly two children, and all data of type \p T currently in
52 the tree are stored in the leaves. Internal nodes of the tree are used to direct \p find
53 operation along the path to the correct leaf. The keys (of \p Key type) stored in internal nodes
54 may or may not be in the set. \p Key type is a subset of \p T type.
55 There should be exactly defined a key extracting functor for converting object of type \p T to
56 object of type \p Key.
58 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeSet can act as
59 a <i>priority queue</i>. In this case you should provide unique compound key, for example,
60 the priority value plus some uniformly distributed random value.
62 @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
63 for uniformly distributed random keys, but in the worst case the complexity is <tt>O(N)</tt>.
65 @note In the current implementation we do not use helping technique described in the original paper.
66 In Hazard Pointer schema helping is too complicated and does not give any observable benefits.
67 Instead of helping, when a thread encounters a concurrent operation it just spins waiting for
68 the operation done. Such solution allows greatly simplify the implementation of tree.
70 <b>Template arguments</b> :
71 - \p GC - safe memory reclamation (i.e. light-weight garbage collector) type, like \p cds::gc::HP, cds::gc::DHP
72 - \p Key - key type, a subset of \p T
73 - \p T - type to be stored in tree's leaf nodes.
74 - \p Traits - set traits, default is \p ellen_bintree::traits
75 It is possible to declare option-based tree with \p ellen_bintree::make_set_traits metafunction
76 instead of \p Traits template argument.
78 @note Do not include <tt><cds/container/impl/ellen_bintree_set.h></tt> header file directly.
79 There are header file for each GC type:
80 - <tt><cds/container/ellen_bintree_set_hp.h></tt> - for \p cds::gc::HP
81 - <tt><cds/container/ellen_bintree_set_dhp.h></tt> - for \p cds::gc::DHP
82 - <tt><cds/container/ellen_bintree_set_rcu.h></tt> - for RCU GC
83 (see \ref cds_container_EllenBinTreeSet_rcu "RCU-based EllenBinTreeSet")
85 @anchor cds_container_EllenBinTreeSet_less
86 <b>Predicate requirements</b>
88 \p Traits::less, \p Traits::compare and other predicates using with member fuctions should accept at least parameters
89 of type \p T and \p Key in any combination.
90 For example, for \p Foo struct with \p std::string key field the appropiate \p less functor is:
99 bool operator()( Foo const& v1, Foo const& v2 ) const
100 { return v1.m_strKey < v2.m_strKey ; }
102 bool operator()( Foo const& v, std::string const& s ) const
103 { return v.m_strKey < s ; }
105 bool operator()( std::string const& s, Foo const& v ) const
106 { return s < v.m_strKey ; }
108 // Support comparing std::string and char const *
109 bool operator()( std::string const& s, char const * p ) const
110 { return s.compare(p) < 0 ; }
112 bool operator()( Foo const& v, char const * p ) const
113 { return v.m_strKey.compare(p) < 0 ; }
115 bool operator()( char const * p, std::string const& s ) const
116 { return s.compare(p) > 0; }
118 bool operator()( char const * p, Foo const& v ) const
119 { return v.m_strKey.compare(p) > 0; }
127 #ifdef CDS_DOXYGEN_INVOKED
128 class Traits = ellen_bintree::traits
133 class EllenBinTreeSet
134 #ifdef CDS_DOXYGEN_INVOKED
135 : public cds::intrusive::EllenBinTree< GC, Key, T, Traits >
137 : public ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits >::type
141 typedef ellen_bintree::details::make_ellen_bintree_set< GC, Key, T, Traits > maker;
142 typedef typename maker::type base_class;
146 typedef GC gc; ///< Garbage collector
147 typedef Key key_type; ///< type of a key to be stored in internal nodes; key is a part of \p value_type
148 typedef T value_type; ///< type of value to be stored in the binary tree
149 typedef Traits traits; ///< Traits template parameter
151 # ifdef CDS_DOXYGEN_INVOKED
152 typedef implementation_defined key_comparator ; ///< key compare functor based on opt::compare and opt::less option setter.
154 typedef typename maker::intrusive_traits::compare key_comparator;
156 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
157 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
158 typedef typename base_class::stat stat; ///< internal statistics type
159 typedef typename traits::key_extractor key_extractor; ///< key extracting functor
160 typedef typename traits::back_off back_off; ///< Back-off strategy
162 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
163 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
164 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
168 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
169 typedef typename base_class::value_type leaf_node;
170 typedef typename base_class::internal_node internal_node;
172 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
177 typedef typename gc::template guarded_ptr< leaf_node, value_type, details::guarded_ptr_cast_set<leaf_node, value_type> > guarded_ptr;
180 /// Default constructor
191 The function creates a node with copy of \p val value
192 and then inserts the node created into the set.
194 The type \p Q should contain at least the complete key for the node.
195 The object of \ref value_type should be constructible from a value of type \p Q.
196 In trivial case, \p Q is equal to \ref value_type.
198 Returns \p true if \p val is inserted into the set, \p false otherwise.
200 template <typename Q>
201 bool insert( Q const& val )
203 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
204 if ( base_class::insert( *sp.get())) {
213 The function allows to split creating of new item into two part:
214 - create item with key only
215 - insert new item into the set
216 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
218 The functor signature is:
220 void func( value_type& val );
222 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
223 \p val no any other changes could be made on this set's item by concurrent threads.
224 The user-defined functor is called only if the inserting is success.
226 template <typename Q, typename Func>
227 bool insert( Q const& val, Func f )
229 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
230 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
239 The operation performs inserting or changing data with lock-free manner.
241 If the item \p val is not found in the set, then \p val is inserted into the set
242 iff \p bAllowInsert is \p true.
243 Otherwise, the functor \p func is called with item found.
244 The functor \p func signature is:
247 void operator()( bool bNew, value_type& item, const Q& val );
252 - \p bNew - \p true if the item has been inserted, \p false otherwise
253 - \p item - item of the set
254 - \p val - argument \p key passed into the \p %update() function
256 The functor can change non-key fields of the \p item; however, \p func must guarantee
257 that during changing no any other modifications could be made on this item by concurrent threads.
259 Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
260 i.e. the node has been inserted or updated,
261 \p second is \p true if new item has been added or \p false if the item with \p key
264 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
266 template <typename Q, typename Func>
267 std::pair<bool, bool> update( const Q& val, Func func, bool bAllowInsert = true )
269 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
270 std::pair<bool, bool> bRes = base_class::update( *sp,
271 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); },
273 if ( bRes.first && bRes.second )
278 template <typename Q, typename Func>
279 CDS_DEPRECATED("ensure() is deprecated, use update()")
280 std::pair<bool, bool> ensure( const Q& val, Func func )
282 return update( val, func, true );
286 /// Inserts data of type \p value_type created in-place from \p args
288 Returns \p true if inserting successful, \p false otherwise.
290 template <typename... Args>
291 bool emplace( Args&&... args )
293 scoped_node_ptr sp( cxx_leaf_node_allocator().MoveNew( std::forward<Args>(args)... ));
294 if ( base_class::insert( *sp.get())) {
301 /// Delete \p key from the set
302 /** \anchor cds_nonintrusive_EllenBinTreeSet_erase_val
304 The item comparator should be able to compare the type \p value_type
307 Return \p true if key is found and deleted, \p false otherwise
309 template <typename Q>
310 bool erase( Q const& key )
312 return base_class::erase( key );
315 /// Deletes the item from the set using \p pred predicate for searching
317 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_erase_val "erase(Q const&)"
318 but \p pred is used for key comparing.
319 \p Less functor has the interface like \p std::less.
320 \p Less must imply the same element order as the comparator used for building the set.
322 template <typename Q, typename Less>
323 bool erase_with( Q const& key, Less pred )
326 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
329 /// Delete \p key from the set
330 /** \anchor cds_nonintrusive_EllenBinTreeSet_erase_func
332 The function searches an item with key \p key, calls \p f functor
333 and deletes the item. If \p key is not found, the functor is not called.
335 The functor \p Func interface:
338 void operator()(value_type const& val);
342 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
343 template parameter \p Q defines the key type searching in the list.
344 The list item comparator should be able to compare the type \p T of list item
347 Return \p true if key is found and deleted, \p false otherwise
349 template <typename Q, typename Func>
350 bool erase( Q const& key, Func f )
352 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
355 /// Deletes the item from the set using \p pred predicate for searching
357 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_erase_func "erase(Q const&, Func)"
358 but \p pred is used for key comparing.
359 \p Less functor has the interface like \p std::less.
360 \p Less must imply the same element order as the comparator used for building the set.
362 template <typename Q, typename Less, typename Func>
363 bool erase_with( Q const& key, Less pred, Func f )
366 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
367 [&f]( leaf_node const& node) { f( node.m_Value ); } );
370 /// Extracts an item with minimal key from the set
372 If the set is not empty, the function returns a guarded pointer to minimum value.
373 If the set is empty, the function returns an empty \p guarded_ptr.
375 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
376 It means that the function gets leftmost leaf of the tree and tries to unlink it.
377 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
378 So, the function returns the item with minimum key at the moment of tree traversing.
380 The guarded pointer prevents deallocation of returned item,
381 see \p cds::gc::guarded_ptr for explanation.
382 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
384 guarded_ptr extract_min()
386 return guarded_ptr( base_class::extract_min_());
389 /// Extracts an item with maximal key from the set
391 If the set is not empty, the function returns a guarded pointer to maximal value.
392 If the set is empty, the function returns an empty \p guarded_ptr.
394 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
395 It means that the function gets rightmost leaf of the tree and tries to unlink it.
396 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
397 So, the function returns the item with maximum key at the moment of tree traversing.
399 The guarded pointer prevents deallocation of returned item,
400 see \p cds::gc::guarded_ptr for explanation.
401 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
403 guarded_ptr extract_max()
405 return guarded_ptr( base_class::extract_max_());
408 /// Extracts an item from the tree
409 /** \anchor cds_nonintrusive_EllenBinTreeSet_extract
410 The function searches an item with key equal to \p key in the tree,
411 unlinks it, and returns an guarded pointer to it.
412 If the item is not found the function returns an empty \p guarded_ptr.
414 The guarded pointer prevents deallocation of returned item,
415 see \p cds::gc::guarded_ptr for explanation.
416 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
418 template <typename Q>
419 guarded_ptr extract( Q const& key )
421 return base_class::extract_( key );
424 /// Extracts an item from the set using \p pred for searching
426 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_extract "extract(Q const&)"
427 but \p pred is used for key compare.
428 \p Less has the interface like \p std::less.
429 \p pred must imply the same element order as the comparator used for building the set.
431 template <typename Q, typename Less>
432 guarded_ptr extract_with( Q const& key, Less pred )
435 return base_class::extract_with_( key,
436 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
439 /// Find the key \p key
441 @anchor cds_nonintrusive_EllenBinTreeSet_find_func
443 The function searches the item with key equal to \p key and calls the functor \p f for item found.
444 The interface of \p Func functor is:
447 void operator()( value_type& item, Q& key );
450 where \p item is the item found, \p key is the <tt>find</tt> function argument.
452 The functor may change non-key fields of \p item. Note that the functor is only guarantee
453 that \p item cannot be disposed during functor is executing.
454 The functor does not serialize simultaneous access to the set's \p item. If such access is
455 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
457 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
458 can modify both arguments.
460 Note the hash functor specified for class \p Traits template parameter
461 should accept a parameter of type \p Q that may be not the same as \p value_type.
463 The function returns \p true if \p key is found, \p false otherwise.
465 template <typename Q, typename Func>
466 bool find( Q& key, Func f )
468 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
471 template <typename Q, typename Func>
472 bool find( Q const& key, Func f )
474 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
478 /// Finds the key \p key using \p pred predicate for searching
480 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_find_func "find(Q&, Func)"
481 but \p pred is used for key comparing.
482 \p Less functor has the interface like \p std::less.
483 \p Less must imply the same element order as the comparator used for building the set.
485 template <typename Q, typename Less, typename Func>
486 bool find_with( Q& key, Less pred, Func f )
489 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
490 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
493 template <typename Q, typename Less, typename Func>
494 bool find_with( Q const& key, Less pred, Func f )
497 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
498 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
502 /// Checks whether the set contains \p key
504 The function searches the item with key equal to \p key
505 and returns \p true if it is found, and \p false otherwise.
507 template <typename Q>
508 bool contains( Q const & key )
510 return base_class::contains( key );
513 template <typename Q>
514 CDS_DEPRECATED("deprecated, use contains()")
515 bool find( Q const & key )
517 return contains( key );
521 /// Checks whether the set contains \p key using \p pred predicate for searching
523 The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
524 \p Less functor has the interface like \p std::less.
525 \p Less must imply the same element order as the comparator used for building the set.
527 template <typename Q, typename Less>
528 bool contains( Q const& key, Less pred )
531 return base_class::contains( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
534 template <typename Q, typename Less>
535 CDS_DEPRECATED("deprecated, use contains()")
536 bool find_with( Q const& key, Less pred )
538 return contains( key, pred );
542 /// Finds \p key and returns the item found
543 /** @anchor cds_nonintrusive_EllenBinTreeSet_get
544 The function searches the item with key equal to \p key and returns the item found as an guarded pointer.
545 The function returns \p true if \p key is found, \p false otherwise.
547 The guarded pointer prevents deallocation of returned item,
548 see \p cds::gc::guarded_ptr for explanation.
549 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
551 template <typename Q>
552 guarded_ptr get( Q const& key )
554 return base_class::get_( key );
557 /// Finds \p key with predicate \p pred and returns the item found
559 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_get "get(Q const&)"
560 but \p pred is used for key comparing.
561 \p Less functor has the interface like \p std::less.
562 \p pred must imply the same element order as the comparator used for building the set.
564 template <typename Q, typename Less>
565 guarded_ptr get_with( Q const& key, Less pred )
568 return base_class::get_with_( key,
569 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
572 /// Clears the set (not atomic)
574 The function unlink all items from the tree.
575 The function is not atomic, thus, in multi-threaded environment with parallel insertions
579 assert( set.empty());
581 the assertion could be raised.
583 For each leaf the \ref disposer will be called after unlinking.
590 /// Checks if the set is empty
593 return base_class::empty();
596 /// Returns item count in the set
598 Only leaf nodes containing user data are counted.
600 The value returned depends on item counter type provided by \p Traits template parameter.
601 If it is \p atomicity::empty_item_counter this function always returns 0.
603 The function is not suitable for checking the tree emptiness, use \p empty()
604 member function for this purpose.
608 return base_class::size();
611 /// Returns const reference to internal statistics
612 stat const& statistics() const
614 return base_class::statistics();
617 /// Checks internal consistency (not atomic, not thread-safe)
619 The debugging function to check internal consistency of the tree.
621 bool check_consistency() const
623 return base_class::check_consistency();
627 }} // namespace cds::container
629 #endif // #ifndef CDSLIB_CONTAINER_IMPL_ELLEN_BINTREE_SET_H