2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
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_MICHAEL_KVLIST_H
32 #define CDSLIB_CONTAINER_IMPL_MICHAEL_KVLIST_H
35 #include <cds/container/details/guarded_ptr_cast.h>
37 namespace cds { namespace container {
39 /// Michael's ordered list fo key-value pair
40 /** @ingroup cds_nonintrusive_list
41 \anchor cds_nonintrusive_MichaelKVList_gc
43 This is key-value variation of non-intrusive MichaelList.
44 Like standard container, this implementation split a value stored into two part -
45 constant key and alterable value.
47 Usually, ordered single-linked list is used as a building block for the hash table implementation.
48 The complexity of searching is <tt>O(N)</tt> where \p N is the item count in the list, not in the
52 - \p GC - garbage collector used
53 - \p Key - key type of an item stored in the list. It should be copy-constructible
54 - \p Value - value type stored in a list
55 - \p Traits - type traits, default is \p michael_list::traits
57 It is possible to declare option-based list with \p cds::container::michael_list::make_traits metafunction istead of \p Traits template
58 argument. For example, the following traits-based declaration of \p gc::HP Michael's list
60 #include <cds/container/michael_kvlist_hp.h>
61 // Declare comparator for the item
63 int operator ()( int i1, int i2 )
70 struct my_traits: public cds::container::michael_list::traits
72 typedef my_compare compare;
75 // Declare traits-based list
76 typedef cds::container::MichaelKVList< cds::gc::HP, int, int, my_traits > traits_based_list;
78 is equivalent for the following option-based list
80 #include <cds/container/michael_kvlist_hp.h>
82 // my_compare is the same
84 // Declare option-based list
85 typedef cds::container::MichaelKVList< cds::gc::HP, int, int,
86 typename cds::container::michael_list::make_traits<
87 cds::container::opt::compare< my_compare > // item comparator option
93 There are different specializations of this template for each garbage collecting schema used.
94 You should include appropriate .h-file depending on GC you are using:
95 - for gc::HP: \code #include <cds/container/michael_kvlist_hp.h> \endcode
96 - for gc::DHP: \code #include <cds/container/michael_kvlist_dhp.h> \endcode
97 - for \ref cds_urcu_desc "RCU": \code #include <cds/container/michael_kvlist_rcu.h> \endcode
98 - for gc::nogc: \code #include <cds/container/michael_kvlist_nogc.h> \endcode
104 #ifdef CDS_DOXYGEN_INVOKED
105 typename Traits = michael_list::traits
111 #ifdef CDS_DOXYGEN_INVOKED
112 protected intrusive::MichaelList< GC, implementation_defined, Traits >
114 protected details::make_michael_kvlist< GC, Key, Value, Traits >::type
118 typedef details::make_michael_kvlist< GC, Key, Value, Traits > maker;
119 typedef typename maker::type base_class;
123 #ifdef CDS_DOXYGEN_INVOKED
124 typedef Key key_type ; ///< Key type
125 typedef Value mapped_type ; ///< Type of value stored in the list
126 typedef std::pair<key_type const, mapped_type> value_type ; ///< key/value pair stored in the list
128 typedef typename maker::key_type key_type;
129 typedef typename maker::value_type mapped_type;
130 typedef typename maker::pair_type value_type;
133 typedef typename base_class::gc gc; ///< Garbage collector used
134 typedef typename base_class::back_off back_off; ///< Back-off strategy used
135 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
136 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
137 typedef typename maker::key_comparator key_comparator; ///< key comparison functor
138 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
142 typedef typename base_class::value_type node_type;
143 typedef typename maker::cxx_allocator cxx_allocator;
144 typedef typename maker::node_deallocator node_deallocator;
145 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
147 typedef typename base_class::atomic_node_ptr head_type;
152 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
156 template <typename K>
157 static node_type * alloc_node(const K& key)
159 return cxx_allocator().New( key );
162 template <typename K, typename V>
163 static node_type * alloc_node( const K& key, const V& val )
165 return cxx_allocator().New( key, val );
168 template <typename K, typename... Args>
169 static node_type * alloc_node( K&& key, Args&&... args )
171 return cxx_allocator().MoveNew( std::forward<K>(key), std::forward<Args>(args)...);
174 static void free_node( node_type * pNode )
176 cxx_allocator().Delete( pNode );
179 struct node_disposer {
180 void operator()( node_type * pNode )
185 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
189 return base_class::m_pHead;
192 head_type const& head() const
194 return base_class::m_pHead;
200 template <bool IsConst>
201 class iterator_type: protected base_class::template iterator_type<IsConst>
203 typedef typename base_class::template iterator_type<IsConst> iterator_base;
205 iterator_type( head_type const& pNode )
206 : iterator_base( pNode )
209 friend class MichaelKVList;
212 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
213 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
215 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
216 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
221 iterator_type( iterator_type const& src )
222 : iterator_base( src )
225 key_type const& key() const
227 typename iterator_base::value_ptr p = iterator_base::operator ->();
228 assert( p != nullptr );
229 return p->m_Data.first;
232 pair_ptr operator ->() const
234 typename iterator_base::value_ptr p = iterator_base::operator ->();
235 return p ? &(p->m_Data) : nullptr;
238 pair_ref operator *() const
240 typename iterator_base::value_ref p = iterator_base::operator *();
244 value_ref val() const
246 typename iterator_base::value_ptr p = iterator_base::operator ->();
247 assert( p != nullptr );
248 return p->m_Data.second;
252 iterator_type& operator ++()
254 iterator_base::operator ++();
259 bool operator ==(iterator_type<C> const& i ) const
261 return iterator_base::operator ==(i);
264 bool operator !=(iterator_type<C> const& i ) const
266 return iterator_base::operator !=(i);
274 The forward iterator for Michael's list has some features:
275 - it has no post-increment operator
276 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
277 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
278 may be thrown if a limit of guard count per thread is exceeded.
279 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
280 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
281 deleting operations it is no guarantee that you iterate all item in the list.
283 @warning Use this iterator on the concurrent container for debugging purpose only.
285 The iterator interface to access item data:
286 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
287 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
288 - <tt> const key_type& key() </tt> - returns a key reference for iterator
289 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
291 For both functions the iterator should not be equal to <tt> end() </tt>
293 typedef iterator_type<false> iterator;
295 /// Const forward iterator
297 For iterator's features and requirements see \ref iterator
299 typedef iterator_type<true> const_iterator;
301 ///@name Forward iterators (only for debugging purpose)
303 /// Returns a forward iterator addressing the first element in a list
305 For empty list \code begin() == end() \endcode
309 return iterator( head() );
312 /// Returns an iterator that addresses the location succeeding the last element in a list
314 Do not use the value returned by <tt>end</tt> function to access any item.
315 Internally, <tt>end</tt> returning value equals to \p nullptr.
317 The returned value can be used only to control reaching the end of the list.
318 For empty list \code begin() == end() \endcode
325 /// Returns a forward const iterator addressing the first element in a list
326 const_iterator begin() const
328 return const_iterator( head() );
331 /// Returns a forward const iterator addressing the first element in a list
332 const_iterator cbegin() const
334 return const_iterator( head() );
337 /// Returns an const iterator that addresses the location succeeding the last element in a list
338 const_iterator end() const
340 return const_iterator();
343 /// Returns an const iterator that addresses the location succeeding the last element in a list
344 const_iterator cend() const
346 return const_iterator();
351 /// Default constructor
353 Initializes empty list
367 /// Inserts new node with key and default value
369 The function creates a node with \p key and default value, and then inserts the node created into the list.
372 - The \p key_type should be constructible from value of type \p K.
373 In trivial case, \p K is equal to \p key_type.
374 - The \p mapped_type should be default-constructible.
376 Returns \p true if inserting successful, \p false otherwise.
378 template <typename K>
379 bool insert( const K& key )
381 return insert_at( head(), key );
384 /// Inserts new node with a key and a value
386 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
389 - The \p key_type should be constructible from \p key of type \p K.
390 - The \p mapped_type should be constructible from \p val of type \p V.
392 Returns \p true if inserting successful, \p false otherwise.
394 template <typename K, typename V>
395 bool insert( const K& key, const V& val )
397 // We cannot use insert with functor here
398 // because we cannot lock inserted node for updating
399 // Therefore, we use separate function
400 return insert_at( head(), key, val );
403 /// Inserts new node and initialize it by a functor
405 This function inserts new node with key \p key and if inserting is successful then it calls
406 \p func functor with signature
409 void operator()( value_type& item );
413 The argument \p item of user-defined functor \p func is the reference
414 to the item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
415 User-defined functor \p func should guarantee that during changing item's value no any other changes
416 could be made on this list's item by concurrent threads.
417 The user-defined functor is called only if inserting is successful.
419 The \p key_type should be constructible from value of type \p K.
421 The function allows to split creating of new item into two part:
422 - create a new item from \p key;
423 - insert the new item into the list;
424 - if inserting is successful, initialize the value of item by calling \p func functor
426 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
427 it is preferable that the initialization should be completed only if inserting is successful.
429 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
431 template <typename K, typename Func>
432 bool insert_with( const K& key, Func func )
434 return insert_with_at( head(), key, func );
437 /// Updates data by \p key
439 The operation performs inserting or replacing the element with lock-free manner.
441 If the \p key not found in the list, then the new item created from \p key
442 will be inserted iff \p bAllowInsert is \p true.
443 (note that in this case the \ref key_type should be constructible from type \p K).
444 Otherwise, if \p key is found, the functor \p func is called with item found.
446 The functor \p Func signature is:
449 void operator()( bool bNew, value_type& item );
453 - \p bNew - \p true if the item has been inserted, \p false otherwise
454 - \p item - the item found or inserted
456 The functor may change any fields of the \p item.second of \p mapped_type;
457 however, \p func must guarantee that during changing no any other modifications
458 could be made on this item by concurrent threads.
460 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
461 \p second is true if new item has been added or \p false if the item with \p key
464 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
466 template <typename K, typename Func>
467 std::pair<bool, bool> update( K const& key, Func f, bool bAllowInsert = true )
469 return update_at( head(), key, f, bAllowInsert );
472 template <typename K, typename Func>
473 CDS_DEPRECATED("ensure() is deprecated, use update()")
474 std::pair<bool, bool> ensure( K const& key, Func f )
476 return update( key, f, true );
480 /// Inserts a new node using move semantics
482 \p key_type field of new item is constructed from \p key argument,
483 \p mapped_type field is done from \p args.
485 Returns \p true if inserting successful, \p false otherwise.
487 template <typename K, typename... Args>
488 bool emplace( K&& key, Args&&... args )
490 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
493 /// Deletes \p key from the list
494 /** \anchor cds_nonintrusive_MichaelKVList_hp_erase_val
496 Returns \p true if \p key is found and has been deleted, \p false otherwise
498 template <typename K>
499 bool erase( K const& key )
501 return erase_at( head(), key, intrusive_key_comparator() );
504 /// Deletes the item from the list using \p pred predicate for searching
506 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_erase_val "erase(K const&)"
507 but \p pred is used for key comparing.
508 \p Less functor has the interface like \p std::less.
509 \p pred must imply the same element order as the comparator used for building the list.
511 template <typename K, typename Less>
512 bool erase_with( K const& key, Less pred )
515 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
518 /// Deletes \p key from the list
519 /** \anchor cds_nonintrusive_MichaelKVList_hp_erase_func
520 The function searches an item with key \p key, calls \p f functor
521 and deletes the item. If \p key is not found, the functor is not called.
523 The functor \p Func interface:
526 void operator()(value_type& val) { ... }
530 Return \p true if key is found and deleted, \p false otherwise
534 template <typename K, typename Func>
535 bool erase( K const& key, Func f )
537 return erase_at( head(), key, intrusive_key_comparator(), f );
540 /// Deletes the item from the list using \p pred predicate for searching
542 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_erase_func "erase(K const&, Func)"
543 but \p pred is used for key comparing.
544 \p Less functor has the interface like \p std::less.
545 \p pred must imply the same element order as the comparator used for building the list.
547 template <typename K, typename Less, typename Func>
548 bool erase_with( K const& key, Less pred, Func f )
551 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
554 /// Extracts the item from the list with specified \p key
555 /** \anchor cds_nonintrusive_MichaelKVList_hp_extract
556 The function searches an item with key equal to \p key,
557 unlinks it from the list, and returns it as \p guarded_ptr.
558 If \p key is not found the function returns an empty guarded pointer.
560 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
562 The \p disposer specified in \p Traits class template parameter is called automatically
563 by garbage collector \p GC specified in class' template parameters when returned \p guarded_ptr object
564 will be destroyed or released.
565 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
569 typedef cds::container::MichaelKVList< cds::gc::HP, int, foo, my_traits > ord_list;
573 ord_list::guarded_ptr gp(theList.extract( 5 ));
578 // Destructor of gp releases internal HP guard
582 template <typename K>
583 guarded_ptr extract( K const& key )
586 extract_at( head(), gp.guard(), key, intrusive_key_comparator() );
590 /// Extracts the item from the list with comparing functor \p pred
592 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_extract "extract(K const&)"
593 but \p pred predicate is used for key comparing.
595 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
597 \p pred must imply the same element order as the comparator used for building the list.
599 template <typename K, typename Less>
600 guarded_ptr extract_with( K const& key, Less pred )
604 extract_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
608 /// Checks whether the list contains \p key
610 The function searches the item with key equal to \p key
611 and returns \p true if it is found, and \p false otherwise.
613 template <typename Q>
614 bool contains( Q const& key )
616 return find_at( head(), key, intrusive_key_comparator() );
619 template <typename Q>
620 CDS_DEPRECATED("deprecated, use contains()")
621 bool find( Q const& key )
623 return contains( key );
627 /// Checks whether the map contains \p key using \p pred predicate for searching
629 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
630 \p Less functor has the interface like \p std::less.
631 \p Less must imply the same element order as the comparator used for building the list.
633 template <typename Q, typename Less>
634 bool contains( Q const& key, Less pred )
637 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
640 template <typename Q, typename Less>
641 CDS_DEPRECATED("deprecated, use contains()")
642 bool find_with( Q const& key, Less pred )
645 return contains( key, pred );
649 /// Finds the key \p key and performs an action with it
650 /** \anchor cds_nonintrusive_MichaelKVList_hp_find_func
651 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
652 The interface of \p Func functor is:
655 void operator()( value_type& item );
658 where \p item is the item found.
660 The functor may change <tt>item.second</tt> that is reference to value of node.
661 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
662 The function does not serialize simultaneous access to the list \p item. If such access is
663 possible you must provide your own synchronization schema to exclude unsafe item modifications.
665 The function returns \p true if \p key is found, \p false otherwise.
667 template <typename Q, typename Func>
668 bool find( Q const& key, Func f )
670 return find_at( head(), key, intrusive_key_comparator(), f );
673 /// Finds the key \p val using \p pred predicate for searching
675 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_find_func "find(Q&, Func)"
676 but \p pred is used for key comparing.
677 \p Less functor has the interface like \p std::less.
678 \p pred must imply the same element order as the comparator used for building the list.
680 template <typename Q, typename Less, typename Func>
681 bool find_with( Q const& key, Less pred, Func f )
684 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
687 /// Finds the \p key and return the item found
688 /** \anchor cds_nonintrusive_MichaelKVList_hp_get
689 The function searches the item with key equal to \p key
690 and returns it as \p guarded_ptr.
691 If \p key is not found the function returns an empty guarded pointer.
693 The \p disposer specified in \p Traits class template parameter is called
694 by garbage collector \p GC automatically when returned \p guarded_ptr object
695 will be destroyed or released.
696 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
700 typedef cds::container::MichaelKVList< cds::gc::HP, int, foo, my_traits > ord_list;
704 ord_list::guarded_ptr gp(theList.get( 5 ));
709 // Destructor of guarded_ptr releases internal HP guard
713 Note the compare functor specified for class \p Traits template parameter
714 should accept a parameter of type \p K that can be not the same as \p key_type.
716 template <typename K>
717 guarded_ptr get( K const& key )
720 get_at( head(), gp.guard(), key, intrusive_key_comparator() );
724 /// Finds the \p key and return the item found
726 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_get "get( guarded_ptr& ptr, K const&)"
727 but \p pred is used for comparing the keys.
729 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
731 \p pred must imply the same element order as the comparator used for building the list.
733 template <typename K, typename Less>
734 guarded_ptr get_with( K const& key, Less pred )
738 get_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
742 /// Checks if the list is empty
745 return base_class::empty();
748 /// Returns list's item count
750 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
751 this function always returns 0.
753 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
754 is empty. To check list emptyness use \p empty() method.
758 return base_class::size();
769 bool insert_node_at( head_type& refHead, node_type * pNode )
771 assert( pNode != nullptr );
772 scoped_node_ptr p( pNode );
773 if ( base_class::insert_at( refHead, *pNode )) {
780 template <typename K>
781 bool insert_at( head_type& refHead, const K& key )
783 return insert_node_at( refHead, alloc_node( key ));
786 template <typename K, typename V>
787 bool insert_at( head_type& refHead, const K& key, const V& val )
789 return insert_node_at( refHead, alloc_node( key, val ));
792 template <typename K, typename Func>
793 bool insert_with_at( head_type& refHead, const K& key, Func f )
795 scoped_node_ptr pNode( alloc_node( key ));
797 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
804 template <typename K, typename... Args>
805 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
807 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
810 template <typename K, typename Func>
811 std::pair<bool, bool> update_at( head_type& refHead, const K& key, Func f, bool bAllowInsert )
813 scoped_node_ptr pNode( alloc_node( key ));
815 std::pair<bool, bool> ret = base_class::update_at( refHead, *pNode,
816 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); },
818 if ( ret.first && ret.second )
824 template <typename K, typename Compare>
825 bool erase_at( head_type& refHead, K const& key, Compare cmp )
827 return base_class::erase_at( refHead, key, cmp );
830 template <typename K, typename Compare, typename Func>
831 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
833 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
835 template <typename K, typename Compare>
836 bool extract_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
838 return base_class::extract_at( refHead, guard, key, cmp );
841 template <typename K, typename Compare>
842 bool find_at( head_type& refHead, K const& key, Compare cmp )
844 return base_class::find_at( refHead, key, cmp );
847 template <typename K, typename Compare, typename Func>
848 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
850 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
853 template <typename K, typename Compare>
854 bool get_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
856 return base_class::get_at( refHead, guard, key, cmp );
862 }} // namespace cds::container
864 #endif // #ifndef CDSLIB_CONTAINER_IMPL_MICHAEL_KVLIST_H