3 #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_MAP_RCU_H
4 #define CDSLIB_CONTAINER_ELLEN_BINTREE_MAP_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 /// Map based on Ellen's et al binary search tree (RCU specialization)
12 /** @ingroup cds_nonintrusive_map
13 @ingroup cds_nonintrusive_tree
14 @anchor cds_container_EllenBinTreeMap_rcu
17 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
19 %EllenBinTreeMap is an unbalanced leaf-oriented binary search tree that implements the <i>map</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 <tt>std::pair<Key const, T></tt>
22 currently in 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 map.
25 Unlike \ref cds_container_EllenBinTreeSet_rcu "EllenBinTreeSet" keys are not a part of \p T type.
26 The map can be represented as a set containing <tt>std::pair< Key const, T> </tt> values.
28 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeMap 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"
42 - \p T - value type to be stored in tree's leaf nodes.
43 - \p Traits - map traits, default is \p ellen_bintree::traits.
44 It is possible to declare option-based tree with \p ellen_bintree::make_map_traits metafunction
45 instead of \p Traits template argument.
47 @note Before including <tt><cds/container/ellen_bintree_map_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.
54 #ifdef CDS_DOXYGEN_INVOKED
55 class Traits = ellen_bintree::traits
60 class EllenBinTreeMap< cds::urcu::gc<RCU>, Key, T, Traits >
61 #ifdef CDS_DOXYGEN_INVOKED
62 : public cds::intrusive::EllenBinTree< cds::urcu::gc<RCU>, Key, T, Traits >
64 : public ellen_bintree::details::make_ellen_bintree_map< cds::urcu::gc<RCU>, Key, T, Traits >::type
68 typedef ellen_bintree::details::make_ellen_bintree_map< cds::urcu::gc<RCU>, Key, T, Traits > maker;
69 typedef typename maker::type base_class;
72 typedef cds::urcu::gc<RCU> gc; ///< RCU Garbage collector
73 typedef Key key_type; ///< type of a key stored in the map
74 typedef T mapped_type; ///< type of value stored in the map
75 typedef std::pair< key_type const, mapped_type > value_type; ///< Key-value pair stored in leaf node of the mp
76 typedef Traits traits; ///< Traits template parameter
78 # ifdef CDS_DOXYGEN_INVOKED
79 typedef implementation_defined key_comparator ; ///< key compare functor based on \p Traits::compare and \p Traits::less
81 typedef typename maker::intrusive_traits::compare key_comparator;
83 typedef typename base_class::item_counter item_counter; ///< Item counting policy
84 typedef typename base_class::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model option
85 typedef typename base_class::node_allocator node_allocator_type; ///< allocator for maintaining internal node
86 typedef typename base_class::stat stat; ///< internal statistics
87 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
88 typedef typename traits::copy_policy copy_policy; ///< key copy policy
89 typedef typename traits::back_off back_off; ///< Back-off strategy
91 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
92 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
93 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
95 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
99 typedef typename base_class::value_type leaf_node;
100 typedef typename base_class::internal_node internal_node;
101 typedef typename base_class::update_desc update_desc;
103 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
105 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
109 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
111 /// pointer to extracted node
112 using exempt_ptr = cds::urcu::exempt_ptr < gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
113 cds::urcu::details::conventional_exempt_member_cast < leaf_node, value_type >
117 /// Default constructor
126 /// Inserts new node with key and default value
128 The function creates a node with \p key and default value, and then inserts the node created into the map.
131 - The \p key_type should be constructible from a value of type \p K.
132 - The \p mapped_type should be default-constructible.
134 RCU \p synchronize() can be called. RCU should not be locked.
136 Returns \p true if inserting successful, \p false otherwise.
138 template <typename K>
139 bool insert( K const& key )
141 return insert_with( key, [](value_type&){} );
146 The function creates a node with copy of \p val value
147 and then inserts the node created into the map.
150 - The \p key_type should be constructible from \p key of type \p K.
151 - The \p value_type should be constructible from \p val of type \p V.
153 RCU \p synchronize() method can be called. RCU should not be locked.
155 Returns \p true if \p val is inserted into the map, \p false otherwise.
157 template <typename K, typename V>
158 bool insert( K const& key, V const& val )
160 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key, val ));
161 if ( base_class::insert( *pNode ))
169 /// Inserts new node and initialize it by a functor
171 This function inserts new node with key \p key and if inserting is successful then it calls
172 \p func functor with signature
175 void operator()( value_type& item );
179 The argument \p item of user-defined functor \p func is the reference
180 to the map's item inserted:
181 - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
182 - <tt>item.second</tt> is a reference to item's value that may be changed.
184 The key_type should be constructible from value of type \p K.
186 The function allows to split creating of new item into two part:
187 - create item from \p key;
188 - insert new item into the map;
189 - if inserting is successful, initialize the value of item by calling \p func functor
191 This can be useful if complete initialization of object of \p value_type is heavyweight and
192 it is preferable that the initialization should be completed only if inserting is successful.
194 RCU \p synchronize() method can be called. RCU should not be locked.
196 template <typename K, typename Func>
197 bool insert_with( K const& key, Func func )
199 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
200 if ( base_class::insert( *pNode, [&func]( leaf_node& item ) { func( item.m_Value ); } )) {
207 /// For key \p key inserts data of type \p value_type created in-place from \p args
209 Returns \p true if inserting successful, \p false otherwise.
211 RCU \p synchronize() method can be called. RCU should not be locked.
213 template <typename K, typename... Args>
214 bool emplace( K&& key, Args&&... args )
216 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( std::forward<K>(key), std::forward<Args>(args)... ));
217 if ( base_class::insert( *pNode )) {
226 The operation performs inserting or changing data with lock-free manner.
228 If the item \p val is not found in the map, then \p val is inserted iff \p bAllowInsert is \p true.
229 Otherwise, the functor \p func is called with item found.
230 The functor \p func signature is:
233 void operator()( bool bNew, value_type& item );
238 - \p bNew - \p true if the item has been inserted, \p false otherwise
239 - \p item - item of the map
241 The functor may change any fields of the \p item.second that is \p mapped_type;
242 however, \p func must guarantee that during changing no any other modifications
243 could be made on this item by concurrent threads.
245 RCU \p synchronize() method can be called. RCU should not be locked.
247 Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
248 i.e. the node has been inserted or updated,
249 \p second is \p true if new item has been added or \p false if the item with \p key
252 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
254 template <typename K, typename Func>
255 std::pair<bool, bool> update( K const& key, Func func, bool bAllowInsert = true )
257 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
258 std::pair<bool, bool> res = base_class::update( *pNode,
259 [&func](bool bNew, leaf_node& item, leaf_node const& ){ func( bNew, item.m_Value ); },
262 if ( res.first && res.second )
267 // Deprecated, use update()
268 template <typename K, typename Func>
269 std::pair<bool, bool> ensure( K const& key, Func func )
271 return update( key, func, true );
275 /// Delete \p key from the map
276 /**\anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_val
278 RCU \p synchronize() method can be called. RCU should not be locked.
280 Return \p true if \p key is found and deleted, \p false otherwise
282 template <typename K>
283 bool erase( K const& key )
285 return base_class::erase(key);
288 /// Deletes the item from the map using \p pred predicate for searching
290 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_val "erase(K const&)"
291 but \p pred is used for key comparing.
292 \p Less functor has the interface like \p std::less.
293 \p Less must imply the same element order as the comparator used for building the map.
295 template <typename K, typename Less>
296 bool erase_with( K const& key, Less pred )
299 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
302 /// Delete \p key from the map
303 /** \anchor cds_nonintrusive_EllenBinTreeMap_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& item) { ... }
315 RCU \p synchronize method can be called. RCU should not be locked.
317 Return \p true if key is found and deleted, \p false otherwise
319 template <typename K, typename Func>
320 bool erase( K const& key, Func f )
322 return base_class::erase( key, [&f]( leaf_node& node) { f( node.m_Value ); } );
325 /// Deletes the item from the map using \p pred predicate for searching
327 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_func "erase(K const&, Func)"
328 but \p pred is used for key comparing.
329 \p Less functor has the interface like \p std::less.
330 \p Less must imply the same element order as the comparator used for building the map.
332 template <typename K, typename Less, typename Func>
333 bool erase_with( K const& key, Less pred, Func f )
336 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
337 [&f]( leaf_node& node) { f( node.m_Value ); } );
340 /// Extracts an item with minimal key from the map
342 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
343 If the set is empty, returns empty \p exempt_ptr.
345 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
346 It means that the function gets leftmost leaf of the tree and tries to unlink it.
347 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
348 So, the function returns the item with minimum key at the moment of tree traversing.
350 RCU \p synchronize method can be called. RCU should NOT be locked.
351 The function does not free the item.
352 The deallocator will be implicitly invoked when the returned object is destroyed or when
353 its \p release() member function is called.
355 exempt_ptr extract_min()
357 return exempt_ptr( base_class::extract_min_());
360 /// Extracts an item with maximal key from the map
362 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
363 If the set is empty, returns empty \p exempt_ptr.
365 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
366 It means that the function gets rightmost leaf of the tree and tries to unlink it.
367 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
368 So, the function returns the item with maximum key at the moment of tree traversing.
370 RCU \p synchronize method can be called. RCU should NOT be locked.
371 The function does not free the item.
372 The deallocator will be implicitly invoked when the returned object is destroyed or when
373 its \p release() is called.
374 @note Before reusing \p result object you should call its \p release() method.
376 exempt_ptr extract_max()
378 return exempt_ptr( base_class::extract_max_());
381 /// Extracts an item from the map
382 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_extract
383 The function searches an item with key equal to \p key in the tree,
384 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
385 If \p key is not found the function returns an empty \p exempt_ptr.
387 RCU \p synchronize method can be called. RCU should NOT be locked.
388 The function does not destroy the item found.
389 The dealloctor will be implicitly invoked when the returned object is destroyed or when
390 its \p release() member function is called.
392 template <typename Q>
393 exempt_ptr extract( Q const& key )
395 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
398 /// Extracts an item from the map using \p pred for searching
400 The function is an analog of \p extract(Q const&)
401 but \p pred is used for key compare.
402 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
403 "predicate requirements".
404 \p pred must imply the same element order as the comparator used for building the map.
406 template <typename Q, typename Less>
407 exempt_ptr extract_with( Q const& key, Less pred )
410 return exempt_ptr( base_class::extract_with_( key,
411 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() ));
414 /// Find the key \p key
415 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc
417 The function searches the item with key equal to \p key and calls the functor \p f for item found.
418 The interface of \p Func functor is:
421 void operator()( value_type& item );
424 where \p item is the item found.
426 The functor may change \p item.second.
428 The function applies RCU lock internally.
430 The function returns \p true if \p key is found, \p false otherwise.
432 template <typename K, typename Func>
433 bool find( K const& key, Func f )
435 return base_class::find( key, [&f](leaf_node& item, K const& ) { f( item.m_Value );});
438 /// Finds the key \p val using \p pred predicate for searching
440 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc "find(K const&, Func)"
441 but \p pred is used for key comparing.
442 \p Less functor has the interface like \p std::less.
443 \p Less must imply the same element order as the comparator used for building the map.
445 template <typename K, typename Less, typename Func>
446 bool find_with( K const& key, Less pred, Func f )
449 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
450 [&f](leaf_node& item, K const& ) { f( item.m_Value );});
453 /// Checks whether the map contains \p key
455 The function searches the item with key equal to \p key
456 and returns \p true if it is found, and \p false otherwise.
458 The function applies RCU lock internally.
460 template <typename K>
461 bool contains( K const& key )
463 return base_class::contains( key );
466 // Deprecated, use contains()
467 template <typename K>
468 bool find( K const& key )
470 return contains( key );
474 /// Checks whether the map contains \p key using \p pred predicate for searching
476 The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
477 \p Less functor has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_rcu_less
478 "Predicate requirements".
479 \p Less must imply the same element order as the comparator used for building the set.
481 template <typename K, typename Less>
482 bool contains( K const& key, Less pred )
485 return base_class::contains( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
488 // Deprecated, use contains()
489 template <typename K, typename Less>
490 bool find_with( K const& key, Less pred )
492 return contains( key, pred );
496 /// Finds \p key and return the item found
497 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_get
498 The function searches the item with key equal to \p key and returns the pointer to item found.
499 If \p key is not found it returns \p nullptr.
501 RCU should be locked before call the function.
502 Returned pointer is valid while RCU is locked.
504 template <typename Q>
505 value_type * get( Q const& key ) const
507 leaf_node * pNode = base_class::get( key );
508 return pNode ? &pNode->m_Value : nullptr;
511 /// Finds \p key with \p pred predicate and return the item found
513 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_get "get(Q const&)"
514 but \p pred is used for comparing the keys.
516 \p Less functor has the semantics like \p std::less but should take arguments of type \p key_type
517 and \p Q in any order.
518 \p pred must imply the same element order as the comparator used for building the map.
520 template <typename Q, typename Less>
521 value_type * get_with( Q const& key, Less pred ) const
524 leaf_node * pNode = base_class::get_with( key,
525 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
526 return pNode ? &pNode->m_Value : nullptr;
535 /// Checks if the map is empty
538 return base_class::empty();
541 /// Returns item count in the map
543 Only leaf nodes containing user data are counted.
545 The value returned depends on item counter type provided by \p Traits template parameter.
546 If it is \p atomicity::empty_item_counter this function always returns 0.
548 The function is not suitable for checking the tree emptiness, use \p empty()
549 member function for this purpose.
553 return base_class::size();
556 /// Returns const reference to internal statistics
557 stat const& statistics() const
559 return base_class::statistics();
562 /// Checks internal consistency (not atomic, not thread-safe)
564 The debugging function to check internal consistency of the tree.
566 bool check_consistency() const
568 return base_class::check_consistency();
571 }} // namespace cds::container
573 #endif //#ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_MAP_RCU_H