3 #ifndef CDSLIB_CONTAINER_SPLIT_LIST_SET_H
4 #define CDSLIB_CONTAINER_SPLIT_LIST_SET_H
6 #include <cds/intrusive/split_list.h>
7 #include <cds/container/details/make_split_list_set.h>
9 namespace cds { namespace container {
11 /// Split-ordered list set
12 /** @ingroup cds_nonintrusive_set
13 \anchor cds_nonintrusive_SplitListSet_hp
15 Hash table implementation based on split-ordered list algorithm discovered by Ori Shalev and Nir Shavit, see
16 - [2003] Ori Shalev, Nir Shavit "Split-Ordered Lists - Lock-free Resizable Hash Tables"
17 - [2008] Nir Shavit "The Art of Multiprocessor Programming"
19 See \p intrusive::SplitListSet for a brief description of the split-list algorithm.
22 - \p GC - Garbage collector used
23 - \p T - type to be stored in the split-list.
24 - \p Traits - type traits, default is \p split_list::traits. Instead of declaring \p split_list::traits -based
25 struct you may apply option-based notation with \p split_list::make_traits metafunction.
27 There are the specializations:
28 - for \ref cds_urcu_desc "RCU" - declared in <tt>cd/container/split_list_set_rcu.h</tt>,
29 see \ref cds_nonintrusive_SplitListSet_rcu "SplitListSet<RCU>".
30 - for \ref cds::gc::nogc declared in <tt>cds/container/split_list_set_nogc.h</tt>,
31 see \ref cds_nonintrusive_SplitListSet_nogc "SplitListSet<gc::nogc>".
35 You should decide what garbage collector you want, and what ordered list you want to use as a base. Split-ordered list
36 is original data structure based on an ordered list.
38 Suppose, you want construct split-list set based on \p gc::DHP GC
39 and \p LazyList as ordered list implementation. So, you beginning your program with following include:
41 #include <cds/container/lazy_list_dhp.h>
42 #include <cds/container/split_list_set.h>
44 namespace cc = cds::container;
46 // The data belonged to split-ordered list
48 int nKey; // key field
49 std::string strValue ; // value field
52 The inclusion order is important: first, include header for ordered-list implementation (for this example, <tt>cds/container/lazy_list_dhp.h</tt>),
53 then the header for split-list set <tt>cds/container/split_list_set.h</tt>.
55 Now, you should declare traits for split-list set. The main parts of traits are a hash functor for the set and a comparing functor for ordered list.
56 Note that we define several function in <tt>foo_hash</tt> and <tt>foo_less</tt> functors for different argument types since we want call our \p %SplitListSet
57 object by the key of type <tt>int</tt> and by the value of type <tt>foo</tt>.
59 The second attention: instead of using \p %LazyList in \p %SplitListSet traits we use a tag \p cds::contaner::lazy_list_tag for the lazy list.
60 The split-list requires significant support from underlying ordered list class and it is not good idea to dive you
61 into deep implementation details of split-list and ordered list interrelations. The tag paradigm simplifies split-list interface.
66 size_t operator()( int key ) const { return std::hash( key ) ; }
67 size_t operator()( foo const& item ) const { return std::hash( item.nKey ) ; }
72 bool operator()(int i, foo const& f ) const { return i < f.nKey ; }
73 bool operator()(foo const& f, int i ) const { return f.nKey < i ; }
74 bool operator()(foo const& f1, foo const& f2) const { return f1.nKey < f2.nKey; }
77 // SplitListSet traits
78 struct foo_set_traits: public cc::split_list::traits
80 typedef cc::lazy_list_tag ordered_list; // what type of ordered list we want to use
81 typedef foo_hash hash; // hash functor for our data stored in split-list set
83 // Type traits for our LazyList class
84 struct ordered_list_traits: public cc::lazy_list::traits
86 typedef foo_less less ; // use our foo_less as comparator to order list nodes
91 Now you are ready to declare our set class based on \p %SplitListSet:
93 typedef cc::SplitListSet< cds::gc::DHP, foo, foo_set_traits > foo_set;
96 You may use the modern option-based declaration instead of classic traits-based one:
98 typedef cc::SplitListSet<
99 cs::gc::DHP // GC used
100 ,foo // type of data stored
101 ,cc::split_list::make_traits< // metafunction to build split-list traits
102 cc::split_list::ordered_list<cc::lazy_list_tag> // tag for underlying ordered list implementation
103 ,cc::opt::hash< foo_hash > // hash functor
104 ,cc::split_list::ordered_list_traits< // ordered list traits desired
105 cc::lazy_list::make_traits< // metafunction to build lazy list traits
106 cc::opt::less< foo_less > // less-based compare functor
112 In case of option-based declaration using split_list::make_traits metafunction
113 the struct \p foo_set_traits is not required.
115 Now, the set of type \p foo_set is ready to use in your program.
117 Note that in this example we show only mandatory \p traits parts, optional ones is the default and they are inherited
118 from \p cds::container::split_list::traits.
119 There are many other options for deep tuning the split-list and ordered-list containers.
124 #ifdef CDS_DOXYGEN_INVOKED
125 class Traits = split_list::traits
131 #ifdef CDS_DOXYGEN_INVOKED
132 protected intrusive::SplitListSet<GC, typename Traits::ordered_list, Traits>
134 protected details::make_split_list_set< GC, T, typename Traits::ordered_list, split_list::details::wrap_set_traits<T, Traits> >::type
139 typedef details::make_split_list_set< GC, T, typename Traits::ordered_list, split_list::details::wrap_set_traits<T, Traits> > maker;
140 typedef typename maker::type base_class;
144 typedef GC gc; ///< Garbage collector
145 typedef T value_type; ///< Type of vlue to be stored in split-list
146 typedef Traits traits; ///< \p Traits template argument
147 typedef typename maker::ordered_list ordered_list; ///< Underlying ordered list class
148 typedef typename base_class::key_comparator key_comparator; ///< key compare functor
150 /// Hash functor for \p %value_type and all its derivatives that you use
151 typedef typename base_class::hash hash;
152 typedef typename base_class::item_counter item_counter; ///< Item counter type
153 typedef typename base_class::stat stat; ///< Internal statistics
156 typedef cds::container::split_list::implementation_tag implementation_tag;
161 typedef typename maker::cxx_node_allocator cxx_node_allocator;
162 typedef typename maker::node_type node_type;
167 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_set<node_type, value_type> > guarded_ptr;
171 template <typename Q>
172 static node_type * alloc_node(Q const& v )
174 return cxx_node_allocator().New( v );
177 template <typename... Args>
178 static node_type * alloc_node( Args&&... args )
180 return cxx_node_allocator().MoveNew( std::forward<Args>( args )... );
183 static void free_node( node_type * pNode )
185 cxx_node_allocator().Delete( pNode );
188 template <typename Q, typename Func>
189 bool find_( Q& val, Func f )
191 return base_class::find( val, [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
194 template <typename Q, typename Less, typename Func>
195 bool find_with_( Q& val, Less pred, Func f )
198 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(),
199 [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
202 struct node_disposer {
203 void operator()( node_type * pNode )
208 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
210 bool insert_node( node_type * pNode )
212 assert( pNode != nullptr );
213 scoped_node_ptr p(pNode);
215 if ( base_class::insert( *pNode ) ) {
227 \p IsConst - constness boolean flag
229 The forward iterator for a split-list has the following features:
230 - it has no post-increment operator
231 - it depends on underlying ordered list iterator
232 - The iterator object cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
233 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
234 deleting operations it is no guarantee that you iterate all item in the split-list.
236 Therefore, the use of iterators in concurrent environment is not good idea. Use it for debug purpose only.
238 template <bool IsConst>
239 class iterator_type: protected base_class::template iterator_type<IsConst>
242 typedef typename base_class::template iterator_type<IsConst> iterator_base_class;
243 friend class SplitListSet;
246 /// Value pointer type (const for const iterator)
247 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
248 /// Value reference type (const for const iterator)
249 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
257 iterator_type( iterator_type const& src )
258 : iterator_base_class( src )
263 explicit iterator_type( iterator_base_class const& src )
264 : iterator_base_class( src )
269 /// Dereference operator
270 value_ptr operator ->() const
272 return &(iterator_base_class::operator->()->m_Value);
275 /// Dereference operator
276 value_ref operator *() const
278 return iterator_base_class::operator*().m_Value;
282 iterator_type& operator ++()
284 iterator_base_class::operator++();
288 /// Assignment operator
289 iterator_type& operator = (iterator_type const& src)
291 iterator_base_class::operator=(src);
295 /// Equality operator
297 bool operator ==(iterator_type<C> const& i ) const
299 return iterator_base_class::operator==(i);
302 /// Equality operator
304 bool operator !=(iterator_type<C> const& i ) const
306 return iterator_base_class::operator!=(i);
311 /// Initializes split-ordered list of default capacity
313 The default capacity is defined in bucket table constructor.
314 See \p intrusive::split_list::expandable_bucket_table, \p intrusive::split_list::static_bucket_table
315 which selects by \p split_list::dynamic_bucket_table option.
321 /// Initializes split-ordered list
323 size_t nItemCount ///< estimated average of item count
324 , size_t nLoadFactor = 1 ///< the load factor - average item count per bucket. Small integer up to 8, default is 1.
326 : base_class( nItemCount, nLoadFactor )
331 typedef iterator_type<false> iterator;
333 /// Const forward iterator
334 typedef iterator_type<true> const_iterator;
336 /// Returns a forward iterator addressing the first element in a set
338 For empty set \code begin() == end() \endcode
342 return iterator( base_class::begin() );
345 /// Returns an iterator that addresses the location succeeding the last element in a set
347 Do not use the value returned by <tt>end</tt> function to access any item.
348 The returned value can be used only to control reaching the end of the set.
349 For empty set \code begin() == end() \endcode
353 return iterator( base_class::end() );
356 /// Returns a forward const iterator addressing the first element in a set
357 const_iterator begin() const
361 /// Returns a forward const iterator addressing the first element in a set
362 const_iterator cbegin() const
364 return const_iterator( base_class::cbegin() );
367 /// Returns an const iterator that addresses the location succeeding the last element in a set
368 const_iterator end() const
372 /// Returns an const iterator that addresses the location succeeding the last element in a set
373 const_iterator cend() const
375 return const_iterator( base_class::cend() );
381 The function creates a node with copy of \p val value
382 and then inserts the node created into the set.
384 The type \p Q should contain as minimum the complete key for the node.
385 The object of \ref value_type should be constructible from a value of type \p Q.
386 In trivial case, \p Q is equal to \ref value_type.
388 Returns \p true if \p val is inserted into the set, \p false otherwise.
390 template <typename Q>
391 bool insert( Q const& val )
393 return insert_node( alloc_node( val ) );
398 The function allows to split creating of new item into two part:
399 - create item with key only
400 - insert new item into the set
401 - if inserting is success, calls \p f functor to initialize value-field of \p val.
403 The functor signature is:
405 void func( value_type& val );
407 where \p val is the item inserted.
409 The user-defined functor is called only if the inserting is success.
411 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
412 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
415 template <typename Q, typename Func>
416 bool insert( Q const& val, Func f )
418 scoped_node_ptr pNode( alloc_node( val ));
420 if ( base_class::insert( *pNode, [&f](node_type& node) { f( node.m_Value ) ; } )) {
427 /// Inserts data of type \p value_type created from \p args
429 Returns \p true if inserting successful, \p false otherwise.
431 template <typename... Args>
432 bool emplace( Args&&... args )
434 return insert_node( alloc_node( std::forward<Args>(args)...));
439 The operation performs inserting or changing data with lock-free manner.
441 If \p key is not found in the set, then \p key is inserted iff \p bAllowInsert is \p true.
442 Otherwise, the functor \p func is called with item found.
444 The functor signature is:
447 void operator()( bool bNew, value_type& item, const Q& val );
451 - \p bNew - \p true if the item has been inserted, \p false otherwise
452 - \p item - item of the set
453 - \p val - argument \p val passed into the \p %update() function
455 The functor may change non-key fields of the \p item.
457 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
458 \p second is true if new item has been added or \p false if the item with \p key
459 already is in the map.
461 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
462 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
465 template <typename Q, typename Func>
466 std::pair<bool, bool> update( Q const& val, Func func, bool bAllowInsert = true )
468 scoped_node_ptr pNode( alloc_node( val ));
470 std::pair<bool, bool> bRet = base_class::update( *pNode,
471 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
472 func( bNew, item.m_Value, val );
475 if ( bRet.first && bRet.second )
480 // Deprecated, use update()
481 template <typename Q, typename Func>
482 std::pair<bool, bool> ensure( Q const& val, Func func )
484 return update( val, func, true );
488 /// Deletes \p key from the set
489 /** \anchor cds_nonintrusive_SplitListSet_erase_val
491 The item comparator should be able to compare the values of type \p value_type
494 Return \p true if key is found and deleted, \p false otherwise
496 template <typename Q>
497 bool erase( Q const& key )
499 return base_class::erase( key );
502 /// Deletes the item from the set using \p pred predicate for searching
504 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
505 but \p pred is used for key comparing.
506 \p Less functor has the interface like \p std::less.
507 \p Less must imply the same element order as the comparator used for building the set.
509 template <typename Q, typename Less>
510 bool erase_with( Q const& key, Less pred )
513 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
516 /// Deletes \p key from the set
517 /** \anchor cds_nonintrusive_SplitListSet_erase_func
519 The function searches an item with key \p key, calls \p f functor
520 and deletes the item. If \p key is not found, the functor is not called.
522 The functor \p Func interface:
525 void operator()(value_type const& val);
529 Since the key of split-list \p value_type is not explicitly specified,
530 template parameter \p Q defines the key type searching in the list.
531 The list item comparator should be able to compare the values of the type \p value_type
534 Return \p true if key is found and deleted, \p false otherwise
536 template <typename Q, typename Func>
537 bool erase( Q const& key, Func f )
539 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
542 /// Deletes the item from the set using \p pred predicate for searching
544 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
545 but \p pred is used for key comparing.
546 \p Less functor has the interface like \p std::less.
547 \p Less must imply the same element order as the comparator used for building the set.
549 template <typename Q, typename Less, typename Func>
550 bool erase_with( Q const& key, Less pred, Func f )
553 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
554 [&f](node_type& node) { f( node.m_Value ); } );
557 /// Extracts the item with specified \p key
558 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
559 The function searches an item with key equal to \p key,
560 unlinks it from the set, and returns it as \p guarded_ptr.
561 If \p key is not found the function returns an empty guarded pointer.
563 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
565 The extracted item is freed automatically when returned \p guarded_ptr object will be destroyed or released.
566 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
570 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
571 splitlist_set theSet;
574 splitlist_set::guarded_ptr gp(theSet.extract( 5 ));
579 // Destructor of gp releases internal HP guard
583 template <typename Q>
584 guarded_ptr extract( Q const& key )
587 extract_( gp.guard(), key );
591 /// Extracts the item using compare functor \p pred
593 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(Q const&)"
594 but \p pred predicate is used for key comparing.
596 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
598 \p pred must imply the same element order as the comparator used for building the set.
600 template <typename Q, typename Less>
601 guarded_ptr extract_with( Q const& key, Less pred )
604 extract_with_( gp.guard(), key, pred );
608 /// Finds the key \p key
609 /** \anchor cds_nonintrusive_SplitListSet_find_func
611 The function searches the item with key equal to \p key and calls the functor \p f for item found.
612 The interface of \p Func functor is:
615 void operator()( value_type& item, Q& key );
618 where \p item is the item found, \p key is the <tt>find</tt> function argument.
620 The functor may change non-key fields of \p item. Note that the functor is only guarantee
621 that \p item cannot be disposed during functor is executing.
622 The functor does not serialize simultaneous access to the set's \p item. If such access is
623 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
625 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
626 may modify both arguments.
628 Note the hash functor specified for class \p Traits template parameter
629 should accept a parameter of type \p Q that can be not the same as \p value_type.
631 The function returns \p true if \p key is found, \p false otherwise.
633 template <typename Q, typename Func>
634 bool find( Q& key, Func f )
636 return find_( key, f );
639 template <typename Q, typename Func>
640 bool find( Q const& key, Func f )
642 return find_( key, f );
646 /// Finds the key \p key using \p pred predicate for searching
648 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
649 but \p pred is used for key comparing.
650 \p Less functor has the interface like \p std::less.
651 \p Less must imply the same element order as the comparator used for building the set.
653 template <typename Q, typename Less, typename Func>
654 bool find_with( Q& key, Less pred, Func f )
656 return find_with_( key, pred, f );
659 template <typename Q, typename Less, typename Func>
660 bool find_with( Q const& key, Less pred, Func f )
662 return find_with_( key, pred, f );
666 /// Checks whether the set contains \p key
668 The function searches the item with key equal to \p key
669 and returns \p true if it is found, and \p false otherwise.
671 Note the hash functor specified for class \p Traits template parameter
672 should accept a parameter of type \p Q that can be not the same as \p value_type.
673 Otherwise, you may use \p contains( Q const&, Less pred ) functions with explicit predicate for key comparing.
675 template <typename Q>
676 bool contains( Q const& key )
678 return base_class::contains( key );
681 // Deprecated, use contains()
682 template <typename Q>
683 bool find( Q const& key )
685 return contains( key );
689 /// Checks whether the map contains \p key using \p pred predicate for searching
691 The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
692 \p Less functor has the interface like \p std::less.
693 \p Less must imply the same element order as the comparator used for building the map.
695 template <typename Q, typename Less>
696 bool contains( Q const& key, Less pred )
699 return base_class::contains( key, typename maker::template predicate_wrapper<Less>::type() );
702 // Deprecated, use contains()
703 template <typename Q, typename Less>
704 bool find_with( Q const& key, Less pred )
706 return contains( key, pred );
710 /// Finds the key \p key and return the item found
711 /** \anchor cds_nonintrusive_SplitListSet_hp_get
712 The function searches the item with key equal to \p key
713 and returns the item found as \p guarded_ptr.
714 If \p key is not found the function returns an empty guarded pointer.
716 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
720 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
721 splitlist_set theSet;
724 splitlist_set::guarded_ptr gp(theSet.get( 5 ));
729 // Destructor of guarded_ptr releases internal HP guard
733 Note the compare functor specified for split-list set
734 should accept a parameter of type \p Q that can be not the same as \p value_type.
736 template <typename Q>
737 guarded_ptr get( Q const& key )
740 get_( gp.guard(), key );
744 /// Finds \p key and return the item found
746 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( Q const&)"
747 but \p pred is used for comparing the keys.
749 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
751 \p pred must imply the same element order as the comparator used for building the set.
753 template <typename Q, typename Less>
754 guarded_ptr get_with( Q const& key, Less pred )
757 get_with_( gp.guard(), key, pred );
761 /// Clears the set (not atomic)
767 /// Checks if the set is empty
769 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
770 Thus, the correct item counting feature is an important part of split-list set implementation.
774 return base_class::empty();
777 /// Returns item count in the set
780 return base_class::size();
783 /// Returns internal statistics
784 stat const& statistics() const
786 return base_class::statistics();
791 using base_class::extract_;
792 using base_class::get_;
794 template <typename Q, typename Less>
795 bool extract_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
798 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
801 template <typename Q, typename Less>
802 bool get_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
805 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
813 }} // namespace cds::container
815 #endif // #ifndef CDSLIB_CONTAINER_SPLIT_LIST_SET_H