3 #ifndef __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H
4 #define __CDS_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
92 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
93 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
94 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
96 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
100 typedef typename base_class::value_type leaf_node;
101 typedef typename base_class::internal_node internal_node;
102 typedef typename base_class::update_desc update_desc;
104 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
106 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
110 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
112 /// pointer to extracted node
113 using exempt_ptr = cds::urcu::exempt_ptr < gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
114 cds::urcu::details::conventional_exempt_member_cast < leaf_node, value_type >
118 /// Default constructor
127 /// Inserts new node with key and default value
129 The function creates a node with \p key and default value, and then inserts the node created into the map.
132 - The \p key_type should be constructible from a value of type \p K.
133 - The \p mapped_type should be default-constructible.
135 RCU \p synchronize() can be called. RCU should not be locked.
137 Returns \p true if inserting successful, \p false otherwise.
139 template <typename K>
140 bool insert( K const& key )
142 return insert_key( key, [](value_type&){} );
147 The function creates a node with copy of \p val value
148 and then inserts the node created into the map.
151 - The \p key_type should be constructible from \p key of type \p K.
152 - The \p value_type should be constructible from \p val of type \p V.
154 RCU \p synchronize() method can be called. RCU should not be locked.
156 Returns \p true if \p val is inserted into the map, \p false otherwise.
158 template <typename K, typename V>
159 bool insert( K const& key, V const& val )
161 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key, val ));
162 if ( base_class::insert( *pNode ))
170 /// Inserts new node and initialize it by a functor
172 This function inserts new node with key \p key and if inserting is successful then it calls
173 \p func functor with signature
176 void operator()( value_type& item );
180 The argument \p item of user-defined functor \p func is the reference
181 to the map's item inserted:
182 - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
183 - <tt>item.second</tt> is a reference to item's value that may be changed.
185 The key_type should be constructible from value of type \p K.
187 The function allows to split creating of new item into two part:
188 - create item from \p key;
189 - insert new item into the map;
190 - if inserting is successful, initialize the value of item by calling \p func functor
192 This can be useful if complete initialization of object of \p value_type is heavyweight and
193 it is preferable that the initialization should be completed only if inserting is successful.
195 RCU \p synchronize() method can be called. RCU should not be locked.
197 template <typename K, typename Func>
198 bool insert_key( const K& key, Func func )
200 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
201 if ( base_class::insert( *pNode, [&func]( leaf_node& item ) { func( item.m_Value ); } )) {
208 /// For key \p key inserts data of type \p value_type created in-place from \p args
210 Returns \p true if inserting successful, \p false otherwise.
212 RCU \p synchronize() method can be called. RCU should not be locked.
214 template <typename K, typename... Args>
215 bool emplace( K&& key, Args&&... args )
217 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( std::forward<K>(key), std::forward<Args>(args)... ));
218 if ( base_class::insert( *pNode )) {
225 /// Ensures that the \p key exists in the map
227 The operation performs inserting or changing data with lock-free manner.
229 If the \p key not found in the map, then the new item created from \p key
230 is inserted into the map (note that in this case the \ref key_type should be
231 constructible from type \p K).
232 Otherwise, the functor \p func is called with item found.
233 The functor \p Func may be a function with signature:
235 void func( bool bNew, value_type& item );
240 void operator()( bool bNew, value_type& item );
245 - \p bNew - \p true if the item has been inserted, \p false otherwise
246 - \p item - item of the list
248 The functor may change any fields of the \p item.second that is \ref value_type.
250 RCU \p synchronize() method can be called. RCU should not be locked.
252 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
253 \p second is true if new item has been added or \p false if the item with \p key
254 already is in the list.
256 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
258 template <typename K, typename Func>
259 std::pair<bool, bool> ensure( K const& key, Func func )
261 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
262 std::pair<bool, bool> res = base_class::ensure( *pNode,
263 [&func](bool bNew, leaf_node& item, leaf_node const& ){ func( bNew, item.m_Value ); }
265 if ( res.first && res.second )
270 /// Delete \p key from the map
271 /**\anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_val
273 RCU \p synchronize() method can be called. RCU should not be locked.
275 Return \p true if \p key is found and deleted, \p false otherwise
277 template <typename K>
278 bool erase( K const& key )
280 return base_class::erase(key);
283 /// Deletes the item from the map using \p pred predicate for searching
285 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_val "erase(K const&)"
286 but \p pred is used for key comparing.
287 \p Less functor has the interface like \p std::less.
288 \p Less must imply the same element order as the comparator used for building the map.
290 template <typename K, typename Less>
291 bool erase_with( K const& key, Less pred )
293 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
296 /// Delete \p key from the map
297 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_func
299 The function searches an item with key \p key, calls \p f functor
300 and deletes the item. If \p key is not found, the functor is not called.
302 The functor \p Func interface:
305 void operator()(value_type& item) { ... }
309 RCU \p synchronize method can be called. RCU should not be locked.
311 Return \p true if key is found and deleted, \p false otherwise
313 template <typename K, typename Func>
314 bool erase( K const& key, Func f )
316 return base_class::erase( key, [&f]( leaf_node& node) { f( node.m_Value ); } );
319 /// Deletes the item from the map using \p pred predicate for searching
321 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_func "erase(K const&, Func)"
322 but \p pred is used for key comparing.
323 \p Less functor has the interface like \p std::less.
324 \p Less must imply the same element order as the comparator used for building the map.
326 template <typename K, typename Less, typename Func>
327 bool erase_with( K const& key, Less pred, Func f )
329 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
330 [&f]( leaf_node& node) { f( node.m_Value ); } );
333 /// Extracts an item with minimal key from the map
335 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
336 If the set is empty, returns empty \p exempt_ptr.
338 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
339 It means that the function gets leftmost leaf of the tree and tries to unlink it.
340 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
341 So, the function returns the item with minimum key at the moment of tree traversing.
343 RCU \p synchronize method can be called. RCU should NOT be locked.
344 The function does not free the item.
345 The deallocator will be implicitly invoked when the returned object is destroyed or when
346 its \p release() member function is called.
348 exempt_ptr extract_min()
350 return exempt_ptr( base_class::extract_min_());
353 /// Extracts an item with maximal key from the map
355 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
356 If the set is empty, returns empty \p exempt_ptr.
358 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
359 It means that the function gets rightmost leaf of the tree and tries to unlink it.
360 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
361 So, the function returns the item with maximum key at the moment of tree traversing.
363 RCU \p synchronize method can be called. RCU should NOT be locked.
364 The function does not free the item.
365 The deallocator will be implicitly invoked when the returned object is destroyed or when
366 its \p release() is called.
367 @note Before reusing \p result object you should call its \p release() method.
369 exempt_ptr extract_max()
371 return exempt_ptr( base_class::extract_max_());
374 /// Extracts an item from the map
375 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_extract
376 The function searches an item with key equal to \p key in the tree,
377 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
378 If \p key is not found the function returns an empty \p exempt_ptr.
380 RCU \p synchronize method can be called. RCU should NOT be locked.
381 The function does not destroy the item found.
382 The dealloctor will be implicitly invoked when the returned object is destroyed or when
383 its \p release() member function is called.
385 template <typename Q>
386 exempt_ptr extract( Q const& key )
388 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
391 /// Extracts an item from the map using \p pred for searching
393 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_extract "extract(exempt_ptr&, Q const&)"
394 but \p pred is used for key compare.
395 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
396 "predicate requirements".
397 \p pred must imply the same element order as the comparator used for building the map.
399 template <typename Q, typename Less>
400 exempt_ptr extract_with( Q const& val, Less pred )
402 return exempt_ptr( base_class::extract_with_( val,
403 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() ));
406 /// Find the key \p key
407 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc
409 The function searches the item with key equal to \p key and calls the functor \p f for item found.
410 The interface of \p Func functor is:
413 void operator()( value_type& item );
416 where \p item is the item found.
418 The functor may change \p item.second.
420 The function applies RCU lock internally.
422 The function returns \p true if \p key is found, \p false otherwise.
424 template <typename K, typename Func>
425 bool find( K const& key, Func f )
427 return base_class::find( key, [&f](leaf_node& item, K const& ) { f( item.m_Value );});
430 /// Finds the key \p val using \p pred predicate for searching
432 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc "find(K const&, Func)"
433 but \p pred is used for key comparing.
434 \p Less functor has the interface like \p std::less.
435 \p Less must imply the same element order as the comparator used for building the map.
437 template <typename K, typename Less, typename Func>
438 bool find_with( K const& key, Less pred, Func f )
440 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
441 [&f](leaf_node& item, K const& ) { f( item.m_Value );});
444 /// Find the key \p key
445 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_val
447 The function searches the item with key equal to \p key
448 and returns \p true if it is found, and \p false otherwise.
450 The function applies RCU lock internally.
452 template <typename K>
453 bool find( K const& key )
455 return base_class::find( key );
458 /// Finds the key \p val using \p pred predicate for searching
460 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_val "find(K const&)"
461 but \p pred is used for key comparing.
462 \p Less functor has the interface like \p std::less.
463 \p Less must imply the same element order as the comparator used for building the map.
465 template <typename K, typename Less>
466 bool find_with( K const& key, Less pred )
468 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
471 /// Finds \p key and return the item found
472 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_get
473 The function searches the item with key equal to \p key and returns the pointer to item found.
474 If \p key is not found it returns \p nullptr.
476 RCU should be locked before call the function.
477 Returned pointer is valid while RCU is locked.
479 template <typename Q>
480 value_type * get( Q const& key ) const
482 leaf_node * pNode = base_class::get( key );
483 return pNode ? &pNode->m_Value : nullptr;
486 /// Finds \p key with \p pred predicate and return the item found
488 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_get "get(Q const&)"
489 but \p pred is used for comparing the keys.
491 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
492 and \p Q in any order.
493 \p pred must imply the same element order as the comparator used for building the map.
495 template <typename Q, typename Less>
496 value_type * get_with( Q const& key, Less pred ) const
498 leaf_node * pNode = base_class::get_with( key,
499 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
500 return pNode ? &pNode->m_Value : nullptr;
509 /// Checks if the map is empty
512 return base_class::empty();
515 /// Returns item count in the map
517 Only leaf nodes containing user data are counted.
519 The value returned depends on item counter type provided by \p Traits template parameter.
520 If it is \p atomicity::empty_item_counter this function always returns 0.
522 The function is not suitable for checking the tree emptiness, use \p empty()
523 member function for this purpose.
527 return base_class::size();
530 /// Returns const reference to internal statistics
531 stat const& statistics() const
533 return base_class::statistics();
536 /// Checks internal consistency (not atomic, not thread-safe)
538 The debugging function to check internal consistency of the tree.
540 bool check_consistency() const
542 return base_class::check_consistency();
545 }} // namespace cds::container
547 #endif //#ifndef __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H