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
98 typedef cds::container::ellen_bintree::implementation_tag implementation_tag;
103 typedef typename base_class::value_type leaf_node;
104 typedef typename base_class::internal_node internal_node;
105 typedef typename base_class::update_desc update_desc;
107 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
109 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
113 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
115 /// pointer to extracted node
116 using exempt_ptr = cds::urcu::exempt_ptr < gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
117 cds::urcu::details::conventional_exempt_member_cast < leaf_node, value_type >
121 /// Default constructor
130 /// Inserts new node with key and default value
132 The function creates a node with \p key and default value, and then inserts the node created into the map.
135 - The \p key_type should be constructible from a value of type \p K.
136 - The \p mapped_type should be default-constructible.
138 RCU \p synchronize() can be called. RCU should not be locked.
140 Returns \p true if inserting successful, \p false otherwise.
142 template <typename K>
143 bool insert( K const& key )
145 return insert_with( key, [](value_type&){} );
150 The function creates a node with copy of \p val value
151 and then inserts the node created into the map.
154 - The \p key_type should be constructible from \p key of type \p K.
155 - The \p value_type should be constructible from \p val of type \p V.
157 RCU \p synchronize() method can be called. RCU should not be locked.
159 Returns \p true if \p val is inserted into the map, \p false otherwise.
161 template <typename K, typename V>
162 bool insert( K const& key, V const& val )
164 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key, val ));
165 if ( base_class::insert( *pNode ))
173 /// Inserts new node and initialize it by a functor
175 This function inserts new node with key \p key and if inserting is successful then it calls
176 \p func functor with signature
179 void operator()( value_type& item );
183 The argument \p item of user-defined functor \p func is the reference
184 to the map's item inserted:
185 - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
186 - <tt>item.second</tt> is a reference to item's value that may be changed.
188 The key_type should be constructible from value of type \p K.
190 The function allows to split creating of new item into two part:
191 - create item from \p key;
192 - insert new item into the map;
193 - if inserting is successful, initialize the value of item by calling \p func functor
195 This can be useful if complete initialization of object of \p value_type is heavyweight and
196 it is preferable that the initialization should be completed only if inserting is successful.
198 RCU \p synchronize() method can be called. RCU should not be locked.
200 template <typename K, typename Func>
201 bool insert_with( K const& key, Func func )
203 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
204 if ( base_class::insert( *pNode, [&func]( leaf_node& item ) { func( item.m_Value ); } )) {
211 /// For key \p key inserts data of type \p value_type created in-place from \p args
213 Returns \p true if inserting successful, \p false otherwise.
215 RCU \p synchronize() method can be called. RCU should not be locked.
217 template <typename K, typename... Args>
218 bool emplace( K&& key, Args&&... args )
220 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( std::forward<K>(key), std::forward<Args>(args)... ));
221 if ( base_class::insert( *pNode )) {
228 /// Ensures that the \p key exists in the map
230 The operation performs inserting or changing data with lock-free manner.
232 If the \p key not found in the map, then the new item created from \p key
233 is inserted into the map (note that in this case the \p key_type should be
234 constructible from type \p K).
235 Otherwise, the functor \p func is called with item found.
236 The functor \p Func may be a function with signature:
238 void func( bool bNew, value_type& item );
243 void operator()( bool bNew, value_type& item );
248 - \p bNew - \p true if the item has been inserted, \p false otherwise
249 - \p item - item of the tree
251 The functor may change any fields of the \p item.second that is \p value_type.
253 RCU \p synchronize() method can be called. RCU should not be locked.
255 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
256 \p second is \p true if new item has been added or \p false if the item with \p key
257 already is in the tree.
259 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
261 template <typename K, typename Func>
262 std::pair<bool, bool> ensure( K const& key, Func func )
264 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
265 std::pair<bool, bool> res = base_class::ensure( *pNode,
266 [&func](bool bNew, leaf_node& item, leaf_node const& ){ func( bNew, item.m_Value ); }
268 if ( res.first && res.second )
273 /// Delete \p key from the map
274 /**\anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_val
276 RCU \p synchronize() method can be called. RCU should not be locked.
278 Return \p true if \p key is found and deleted, \p false otherwise
280 template <typename K>
281 bool erase( K const& key )
283 return base_class::erase(key);
286 /// Deletes the item from the map using \p pred predicate for searching
288 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_val "erase(K const&)"
289 but \p pred is used for key comparing.
290 \p Less functor has the interface like \p std::less.
291 \p Less must imply the same element order as the comparator used for building the map.
293 template <typename K, typename Less>
294 bool erase_with( K const& key, Less pred )
297 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
300 /// Delete \p key from the map
301 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_func
303 The function searches an item with key \p key, calls \p f functor
304 and deletes the item. If \p key is not found, the functor is not called.
306 The functor \p Func interface:
309 void operator()(value_type& item) { ... }
313 RCU \p synchronize method can be called. RCU should not be locked.
315 Return \p true if key is found and deleted, \p false otherwise
317 template <typename K, typename Func>
318 bool erase( K const& key, Func f )
320 return base_class::erase( key, [&f]( leaf_node& node) { f( node.m_Value ); } );
323 /// Deletes the item from the map using \p pred predicate for searching
325 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_func "erase(K const&, Func)"
326 but \p pred is used for key comparing.
327 \p Less functor has the interface like \p std::less.
328 \p Less must imply the same element order as the comparator used for building the map.
330 template <typename K, typename Less, typename Func>
331 bool erase_with( K const& key, Less pred, Func f )
334 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
335 [&f]( leaf_node& node) { f( node.m_Value ); } );
338 /// Extracts an item with minimal key from the map
340 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
341 If the set is empty, returns empty \p exempt_ptr.
343 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
344 It means that the function gets leftmost leaf of the tree and tries to unlink it.
345 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
346 So, the function returns the item with minimum key at the moment of tree traversing.
348 RCU \p synchronize method can be called. RCU should NOT be locked.
349 The function does not free the item.
350 The deallocator will be implicitly invoked when the returned object is destroyed or when
351 its \p release() member function is called.
353 exempt_ptr extract_min()
355 return exempt_ptr( base_class::extract_min_());
358 /// Extracts an item with maximal key from the map
360 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
361 If the set is empty, returns empty \p exempt_ptr.
363 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
364 It means that the function gets rightmost leaf of the tree and tries to unlink it.
365 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
366 So, the function returns the item with maximum key at the moment of tree traversing.
368 RCU \p synchronize method can be called. RCU should NOT be locked.
369 The function does not free the item.
370 The deallocator will be implicitly invoked when the returned object is destroyed or when
371 its \p release() is called.
372 @note Before reusing \p result object you should call its \p release() method.
374 exempt_ptr extract_max()
376 return exempt_ptr( base_class::extract_max_());
379 /// Extracts an item from the map
380 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_extract
381 The function searches an item with key equal to \p key in the tree,
382 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
383 If \p key is not found the function returns an empty \p exempt_ptr.
385 RCU \p synchronize method can be called. RCU should NOT be locked.
386 The function does not destroy the item found.
387 The dealloctor will be implicitly invoked when the returned object is destroyed or when
388 its \p release() member function is called.
390 template <typename Q>
391 exempt_ptr extract( Q const& key )
393 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
396 /// Extracts an item from the map using \p pred for searching
398 The function is an analog of \p extract(Q const&)
399 but \p pred is used for key compare.
400 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
401 "predicate requirements".
402 \p pred must imply the same element order as the comparator used for building the map.
404 template <typename Q, typename Less>
405 exempt_ptr extract_with( Q const& key, Less pred )
408 return exempt_ptr( base_class::extract_with_( key,
409 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() ));
412 /// Find the key \p key
413 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc
415 The function searches the item with key equal to \p key and calls the functor \p f for item found.
416 The interface of \p Func functor is:
419 void operator()( value_type& item );
422 where \p item is the item found.
424 The functor may change \p item.second.
426 The function applies RCU lock internally.
428 The function returns \p true if \p key is found, \p false otherwise.
430 template <typename K, typename Func>
431 bool find( K const& key, Func f )
433 return base_class::find( key, [&f](leaf_node& item, K const& ) { f( item.m_Value );});
436 /// Finds the key \p val using \p pred predicate for searching
438 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc "find(K const&, Func)"
439 but \p pred is used for key comparing.
440 \p Less functor has the interface like \p std::less.
441 \p Less must imply the same element order as the comparator used for building the map.
443 template <typename K, typename Less, typename Func>
444 bool find_with( K const& key, Less pred, Func f )
447 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
448 [&f](leaf_node& item, K const& ) { f( item.m_Value );});
451 /// Find the key \p key
452 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_val
454 The function searches the item with key equal to \p key
455 and returns \p true if it is found, and \p false otherwise.
457 The function applies RCU lock internally.
459 template <typename K>
460 bool find( K const& key )
462 return base_class::find( key );
465 /// Finds the key \p val using \p pred predicate for searching
467 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_val "find(K const&)"
468 but \p pred is used for key comparing.
469 \p Less functor has the interface like \p std::less.
470 \p Less must imply the same element order as the comparator used for building the map.
472 template <typename K, typename Less>
473 bool find_with( K const& key, Less pred )
476 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
479 /// Finds \p key and return the item found
480 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_get
481 The function searches the item with key equal to \p key and returns the pointer to item found.
482 If \p key is not found it returns \p nullptr.
484 RCU should be locked before call the function.
485 Returned pointer is valid while RCU is locked.
487 template <typename Q>
488 value_type * get( Q const& key ) const
490 leaf_node * pNode = base_class::get( key );
491 return pNode ? &pNode->m_Value : nullptr;
494 /// Finds \p key with \p pred predicate and return the item found
496 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_get "get(Q const&)"
497 but \p pred is used for comparing the keys.
499 \p Less functor has the semantics like \p std::less but should take arguments of type \p key_type
500 and \p Q in any order.
501 \p pred must imply the same element order as the comparator used for building the map.
503 template <typename Q, typename Less>
504 value_type * get_with( Q const& key, Less pred ) const
507 leaf_node * pNode = base_class::get_with( key,
508 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
509 return pNode ? &pNode->m_Value : nullptr;
518 /// Checks if the map is empty
521 return base_class::empty();
524 /// Returns item count in the map
526 Only leaf nodes containing user data are counted.
528 The value returned depends on item counter type provided by \p Traits template parameter.
529 If it is \p atomicity::empty_item_counter this function always returns 0.
531 The function is not suitable for checking the tree emptiness, use \p empty()
532 member function for this purpose.
536 return base_class::size();
539 /// Returns const reference to internal statistics
540 stat const& statistics() const
542 return base_class::statistics();
545 /// Checks internal consistency (not atomic, not thread-safe)
547 The debugging function to check internal consistency of the tree.
549 bool check_consistency() const
551 return base_class::check_consistency();
554 }} // namespace cds::container
556 #endif //#ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_MAP_RCU_H