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)...));
437 /// Ensures that the \p item exists in the set
439 The operation performs inserting or changing data with lock-free manner.
441 If the \p val key not found in the set, then the new item created from \p val
442 is inserted into the set. Otherwise, the functor \p func is called with the item found.
443 The functor \p Func should be a function with signature:
445 void func( bool bNew, value_type& item, const Q& val );
450 void operator()( bool bNew, value_type& item, const Q& val );
455 - \p bNew - \p true if the item has been inserted, \p false otherwise
456 - \p item - item of the set
457 - \p val - argument \p val passed into the \p ensure function
459 The functor may change non-key fields of the \p item.
461 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
462 \p second is true if new item has been added or \p false if the item with \p key
463 already is in the set.
465 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
466 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
469 template <typename Q, typename Func>
470 std::pair<bool, bool> ensure( Q const& val, Func func )
472 scoped_node_ptr pNode( alloc_node( val ));
474 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
475 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
476 func( bNew, item.m_Value, val );
479 if ( bRet.first && bRet.second )
484 /// Deletes \p key from the set
485 /** \anchor cds_nonintrusive_SplitListSet_erase_val
487 The item comparator should be able to compare the values of type \p value_type
490 Return \p true if key is found and deleted, \p false otherwise
492 template <typename Q>
493 bool erase( Q const& key )
495 return base_class::erase( key );
498 /// Deletes the item from the set using \p pred predicate for searching
500 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
501 but \p pred is used for key comparing.
502 \p Less functor has the interface like \p std::less.
503 \p Less must imply the same element order as the comparator used for building the set.
505 template <typename Q, typename Less>
506 bool erase_with( Q const& key, Less pred )
509 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
512 /// Deletes \p key from the set
513 /** \anchor cds_nonintrusive_SplitListSet_erase_func
515 The function searches an item with key \p key, calls \p f functor
516 and deletes the item. If \p key is not found, the functor is not called.
518 The functor \p Func interface:
521 void operator()(value_type const& val);
525 Since the key of split-list \p value_type is not explicitly specified,
526 template parameter \p Q defines the key type searching in the list.
527 The list item comparator should be able to compare the values of the type \p value_type
530 Return \p true if key is found and deleted, \p false otherwise
532 template <typename Q, typename Func>
533 bool erase( Q const& key, Func f )
535 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
538 /// Deletes the item from the set using \p pred predicate for searching
540 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
541 but \p pred is used for key comparing.
542 \p Less functor has the interface like \p std::less.
543 \p Less must imply the same element order as the comparator used for building the set.
545 template <typename Q, typename Less, typename Func>
546 bool erase_with( Q const& key, Less pred, Func f )
549 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
550 [&f](node_type& node) { f( node.m_Value ); } );
553 /// Extracts the item with specified \p key
554 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
555 The function searches an item with key equal to \p key,
556 unlinks it from the set, and returns it as \p guarded_ptr.
557 If \p key is not found the function returns an empty guarded pointer.
559 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
561 The extracted item is freed automatically when returned \p guarded_ptr object will be destroyed or released.
562 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
566 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
567 splitlist_set theSet;
570 splitlist_set::guarded_ptr gp(theSet.extract( 5 ));
575 // Destructor of gp releases internal HP guard
579 template <typename Q>
580 guarded_ptr extract( Q const& key )
583 extract_( gp.guard(), key );
587 /// Extracts the item using compare functor \p pred
589 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(Q const&)"
590 but \p pred predicate is used for key comparing.
592 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
594 \p pred must imply the same element order as the comparator used for building the set.
596 template <typename Q, typename Less>
597 guarded_ptr extract_with( Q const& key, Less pred )
600 extract_with_( gp.guard(), key, pred );
604 /// Finds the key \p key
605 /** \anchor cds_nonintrusive_SplitListSet_find_func
607 The function searches the item with key equal to \p key and calls the functor \p f for item found.
608 The interface of \p Func functor is:
611 void operator()( value_type& item, Q& key );
614 where \p item is the item found, \p key is the <tt>find</tt> function argument.
616 The functor may change non-key fields of \p item. Note that the functor is only guarantee
617 that \p item cannot be disposed during functor is executing.
618 The functor does not serialize simultaneous access to the set's \p item. If such access is
619 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
621 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
622 may modify both arguments.
624 Note the hash functor specified for class \p Traits template parameter
625 should accept a parameter of type \p Q that can be not the same as \p value_type.
627 The function returns \p true if \p key is found, \p false otherwise.
629 template <typename Q, typename Func>
630 bool find( Q& key, Func f )
632 return find_( key, f );
635 template <typename Q, typename Func>
636 bool find( Q const& key, Func f )
638 return find_( key, f );
642 /// Finds the key \p key using \p pred predicate for searching
644 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
645 but \p pred is used for key comparing.
646 \p Less functor has the interface like \p std::less.
647 \p Less must imply the same element order as the comparator used for building the set.
649 template <typename Q, typename Less, typename Func>
650 bool find_with( Q& key, Less pred, Func f )
652 return find_with_( key, pred, f );
655 template <typename Q, typename Less, typename Func>
656 bool find_with( Q const& key, Less pred, Func f )
658 return find_with_( key, pred, f );
662 /// Finds the key \p key
663 /** \anchor cds_nonintrusive_SplitListSet_find_val
665 The function searches the item with key equal to \p key
666 and returns \p true if it is found, and \p false otherwise.
668 Note the hash functor specified for class \p Traits template parameter
669 should accept a parameter of type \p Q that can be not the same as \ref value_type.
671 template <typename Q>
672 bool find( Q const& key )
674 return base_class::find( key );
677 /// Finds the key \p key using \p pred predicate for searching
679 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
680 but \p pred is used for key comparing.
681 \p Less functor has the interface like \p std::less.
682 \p Less must imply the same element order as the comparator used for building the set.
684 template <typename Q, typename Less>
685 bool find_with( Q const& key, Less pred )
688 return base_class::find_with( key, typename maker::template predicate_wrapper<Less>::type() );
691 /// Finds the key \p key and return the item found
692 /** \anchor cds_nonintrusive_SplitListSet_hp_get
693 The function searches the item with key equal to \p key
694 and returns the item found as \p guarded_ptr.
695 If \p key is not found the function returns an empty guarded pointer.
697 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
701 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
702 splitlist_set theSet;
705 splitlist_set::guarded_ptr gp(theSet.get( 5 ));
710 // Destructor of guarded_ptr releases internal HP guard
714 Note the compare functor specified for split-list set
715 should accept a parameter of type \p Q that can be not the same as \p value_type.
717 template <typename Q>
718 guarded_ptr get( Q const& key )
721 get_( gp.guard(), key );
725 /// Finds \p key and return the item found
727 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( Q const&)"
728 but \p pred is used for comparing the keys.
730 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
732 \p pred must imply the same element order as the comparator used for building the set.
734 template <typename Q, typename Less>
735 guarded_ptr get_with( Q const& key, Less pred )
738 get_with_( gp.guard(), key, pred );
742 /// Clears the set (not atomic)
748 /// Checks if the set is empty
750 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
751 Thus, the correct item counting feature is an important part of split-list set implementation.
755 return base_class::empty();
758 /// Returns item count in the set
761 return base_class::size();
764 /// Returns internal statistics
765 stat const& statistics() const
767 return base_class::statistics();
772 using base_class::extract_;
773 using base_class::get_;
775 template <typename Q, typename Less>
776 bool extract_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
779 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
782 template <typename Q, typename Less>
783 bool get_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
786 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
794 }} // namespace cds::container
796 #endif // #ifndef CDSLIB_CONTAINER_SPLIT_LIST_SET_H