3 #ifndef __CDS_CONTAINER_SPLIT_LIST_SET_H
4 #define __CDS_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
157 typedef typename maker::cxx_node_allocator cxx_node_allocator;
158 typedef typename maker::node_type node_type;
163 typedef cds::gc::guarded_ptr< gc, node_type, value_type, details::guarded_ptr_cast_set<node_type, value_type> > guarded_ptr;
167 template <typename Q>
168 static node_type * alloc_node(Q const& v )
170 return cxx_node_allocator().New( v );
173 template <typename... Args>
174 static node_type * alloc_node( Args&&... args )
176 return cxx_node_allocator().MoveNew( std::forward<Args>( args )... );
179 static void free_node( node_type * pNode )
181 cxx_node_allocator().Delete( pNode );
184 template <typename Q, typename Func>
185 bool find_( Q& val, Func f )
187 return base_class::find( val, [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
190 template <typename Q, typename Less, typename Func>
191 bool find_with_( Q& val, Less pred, Func f )
193 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(),
194 [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
197 struct node_disposer {
198 void operator()( node_type * pNode )
203 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
205 bool insert_node( node_type * pNode )
207 assert( pNode != nullptr );
208 scoped_node_ptr p(pNode);
210 if ( base_class::insert( *pNode ) ) {
222 \p IsConst - constness boolean flag
224 The forward iterator for a split-list has the following features:
225 - it has no post-increment operator
226 - it depends on underlying ordered list iterator
227 - The iterator object cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
228 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
229 deleting operations it is no guarantee that you iterate all item in the split-list.
231 Therefore, the use of iterators in concurrent environment is not good idea. Use it for debug purpose only.
233 template <bool IsConst>
234 class iterator_type: protected base_class::template iterator_type<IsConst>
237 typedef typename base_class::template iterator_type<IsConst> iterator_base_class;
238 friend class SplitListSet;
241 /// Value pointer type (const for const iterator)
242 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
243 /// Value reference type (const for const iterator)
244 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
252 iterator_type( iterator_type const& src )
253 : iterator_base_class( src )
258 explicit iterator_type( iterator_base_class const& src )
259 : iterator_base_class( src )
264 /// Dereference operator
265 value_ptr operator ->() const
267 return &(iterator_base_class::operator->()->m_Value);
270 /// Dereference operator
271 value_ref operator *() const
273 return iterator_base_class::operator*().m_Value;
277 iterator_type& operator ++()
279 iterator_base_class::operator++();
283 /// Assignment operator
284 iterator_type& operator = (iterator_type const& src)
286 iterator_base_class::operator=(src);
290 /// Equality operator
292 bool operator ==(iterator_type<C> const& i ) const
294 return iterator_base_class::operator==(i);
297 /// Equality operator
299 bool operator !=(iterator_type<C> const& i ) const
301 return iterator_base_class::operator!=(i);
306 /// Initializes split-ordered list of default capacity
308 The default capacity is defined in bucket table constructor.
309 See \p intrusive::split_list::expandable_bucket_table, \p intrusive::split_list::static_bucket_table
310 which selects by \p split_list::dynamic_bucket_table option.
316 /// Initializes split-ordered list
318 size_t nItemCount ///< estimated average of item count
319 , size_t nLoadFactor = 1 ///< the load factor - average item count per bucket. Small integer up to 8, default is 1.
321 : base_class( nItemCount, nLoadFactor )
326 typedef iterator_type<false> iterator;
328 /// Const forward iterator
329 typedef iterator_type<true> const_iterator;
331 /// Returns a forward iterator addressing the first element in a set
333 For empty set \code begin() == end() \endcode
337 return iterator( base_class::begin() );
340 /// Returns an iterator that addresses the location succeeding the last element in a set
342 Do not use the value returned by <tt>end</tt> function to access any item.
343 The returned value can be used only to control reaching the end of the set.
344 For empty set \code begin() == end() \endcode
348 return iterator( base_class::end() );
351 /// Returns a forward const iterator addressing the first element in a set
352 const_iterator begin() const
356 /// Returns a forward const iterator addressing the first element in a set
357 const_iterator cbegin() const
359 return const_iterator( base_class::cbegin() );
362 /// Returns an const iterator that addresses the location succeeding the last element in a set
363 const_iterator end() const
367 /// Returns an const iterator that addresses the location succeeding the last element in a set
368 const_iterator cend() const
370 return const_iterator( base_class::cend() );
376 The function creates a node with copy of \p val value
377 and then inserts the node created into the set.
379 The type \p Q should contain as minimum the complete key for the node.
380 The object of \ref value_type should be constructible from a value of type \p Q.
381 In trivial case, \p Q is equal to \ref value_type.
383 Returns \p true if \p val is inserted into the set, \p false otherwise.
385 template <typename Q>
386 bool insert( Q const& val )
388 return insert_node( alloc_node( val ) );
393 The function allows to split creating of new item into two part:
394 - create item with key only
395 - insert new item into the set
396 - if inserting is success, calls \p f functor to initialize value-field of \p val.
398 The functor signature is:
400 void func( value_type& val );
402 where \p val is the item inserted.
404 The user-defined functor is called only if the inserting is success.
406 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
407 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
410 template <typename Q, typename Func>
411 bool insert( Q const& val, Func f )
413 scoped_node_ptr pNode( alloc_node( val ));
415 if ( base_class::insert( *pNode, [&f](node_type& node) { f( node.m_Value ) ; } )) {
422 /// Inserts data of type \p value_type created from \p args
424 Returns \p true if inserting successful, \p false otherwise.
426 template <typename... Args>
427 bool emplace( Args&&... args )
429 return insert_node( alloc_node( std::forward<Args>(args)...));
432 /// Ensures that the \p item exists in the set
434 The operation performs inserting or changing data with lock-free manner.
436 If the \p val key not found in the set, then the new item created from \p val
437 is inserted into the set. Otherwise, the functor \p func is called with the item found.
438 The functor \p Func should be a function with signature:
440 void func( bool bNew, value_type& item, const Q& val );
445 void operator()( bool bNew, value_type& item, const Q& val );
450 - \p bNew - \p true if the item has been inserted, \p false otherwise
451 - \p item - item of the set
452 - \p val - argument \p val passed into the \p ensure function
454 The functor may change non-key fields of the \p item.
456 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
457 \p second is true if new item has been added or \p false if the item with \p key
458 already is in the set.
460 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
461 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
464 template <typename Q, typename Func>
465 std::pair<bool, bool> ensure( Q const& val, Func func )
467 scoped_node_ptr pNode( alloc_node( val ));
469 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
470 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
471 func( bNew, item.m_Value, val );
474 if ( bRet.first && bRet.second )
479 /// Deletes \p key from the set
480 /** \anchor cds_nonintrusive_SplitListSet_erase_val
482 The item comparator should be able to compare the values of type \p value_type
485 Return \p true if key is found and deleted, \p false otherwise
487 template <typename Q>
488 bool erase( Q const& key )
490 return base_class::erase( key );
493 /// Deletes the item from the set using \p pred predicate for searching
495 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
496 but \p pred is used for key comparing.
497 \p Less functor has the interface like \p std::less.
498 \p Less must imply the same element order as the comparator used for building the set.
500 template <typename Q, typename Less>
501 bool erase_with( Q const& key, Less pred )
503 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
506 /// Deletes \p key from the set
507 /** \anchor cds_nonintrusive_SplitListSet_erase_func
509 The function searches an item with key \p key, calls \p f functor
510 and deletes the item. If \p key is not found, the functor is not called.
512 The functor \p Func interface:
515 void operator()(value_type const& val);
519 Since the key of split-list \p value_type is not explicitly specified,
520 template parameter \p Q defines the key type searching in the list.
521 The list item comparator should be able to compare the values of the type \p value_type
524 Return \p true if key is found and deleted, \p false otherwise
526 template <typename Q, typename Func>
527 bool erase( Q const& key, Func f )
529 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
532 /// Deletes the item from the set using \p pred predicate for searching
534 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
535 but \p pred is used for key comparing.
536 \p Less functor has the interface like \p std::less.
537 \p Less must imply the same element order as the comparator used for building the set.
539 template <typename Q, typename Less, typename Func>
540 bool erase_with( Q const& key, Less pred, Func f )
542 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
543 [&f](node_type& node) { f( node.m_Value ); } );
546 /// Extracts the item with specified \p key
547 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
548 The function searches an item with key equal to \p key,
549 unlinks it from the set, and returns it in \p dest parameter.
550 If the item with key equal to \p key is not found the function returns \p false.
552 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
554 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
555 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
559 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
560 splitlist_set theSet;
563 splitlist_set::guarded_ptr gp;
564 theSet.extract( gp, 5 );
568 // Destructor of gp releases internal HP guard
572 template <typename Q>
573 bool extract( guarded_ptr& dest, Q const& key )
575 return extract_( dest.guard(), key );
578 /// Extracts the item using compare functor \p pred
580 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(guarded_ptr&, Q const&)"
581 but \p pred predicate is used for key comparing.
583 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
585 \p pred must imply the same element order as the comparator used for building the set.
587 template <typename Q, typename Less>
588 bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
590 return extract_with_( dest.guard(), key, pred );
593 /// Finds the key \p key
594 /** \anchor cds_nonintrusive_SplitListSet_find_func
596 The function searches the item with key equal to \p key and calls the functor \p f for item found.
597 The interface of \p Func functor is:
600 void operator()( value_type& item, Q& key );
603 where \p item is the item found, \p key is the <tt>find</tt> function argument.
605 The functor may change non-key fields of \p item. Note that the functor is only guarantee
606 that \p item cannot be disposed during functor is executing.
607 The functor does not serialize simultaneous access to the set's \p item. If such access is
608 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
610 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
611 may modify both arguments.
613 Note the hash functor specified for class \p Traits template parameter
614 should accept a parameter of type \p Q that can be not the same as \p value_type.
616 The function returns \p true if \p key is found, \p false otherwise.
618 template <typename Q, typename Func>
619 bool find( Q& key, Func f )
621 return find_( key, f );
624 template <typename Q, typename Func>
625 bool find( Q const& key, Func f )
627 return find_( key, f );
631 /// Finds the key \p key using \p pred predicate for searching
633 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
634 but \p pred is used for key comparing.
635 \p Less functor has the interface like \p std::less.
636 \p Less must imply the same element order as the comparator used for building the set.
638 template <typename Q, typename Less, typename Func>
639 bool find_with( Q& key, Less pred, Func f )
641 return find_with_( key, pred, f );
644 template <typename Q, typename Less, typename Func>
645 bool find_with( Q const& key, Less pred, Func f )
647 return find_with_( key, pred, f );
651 /// Finds the key \p key
652 /** \anchor cds_nonintrusive_SplitListSet_find_val
654 The function searches the item with key equal to \p key
655 and returns \p true if it is found, and \p false otherwise.
657 Note the hash functor specified for class \p Traits template parameter
658 should accept a parameter of type \p Q that can be not the same as \ref value_type.
660 template <typename Q>
661 bool find( Q const& key )
663 return base_class::find( key );
666 /// Finds the key \p key using \p pred predicate for searching
668 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
669 but \p pred is used for key comparing.
670 \p Less functor has the interface like \p std::less.
671 \p Less must imply the same element order as the comparator used for building the set.
673 template <typename Q, typename Less>
674 bool find_with( Q const& key, Less pred )
676 return base_class::find_with( key, typename maker::template predicate_wrapper<Less>::type() );
679 /// Finds the key \p key and return the item found
680 /** \anchor cds_nonintrusive_SplitListSet_hp_get
681 The function searches the item with key equal to \p key
682 and assigns the item found to guarded pointer \p ptr.
683 The function returns \p true if \p key is found, and \p false otherwise.
684 If \p key is not found the \p ptr parameter is not changed.
686 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
690 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
691 splitlist_set theSet;
694 splitlist_set::guarded_ptr gp;
695 if ( theSet.get( gp, 5 )) {
699 // Destructor of guarded_ptr releases internal HP guard
703 Note the compare functor specified for split-list set
704 should accept a parameter of type \p Q that can be not the same as \p value_type.
706 template <typename Q>
707 bool get( guarded_ptr& ptr, Q const& key )
709 return get_( ptr.guard(), key );
712 /// Finds \p key and return the item found
714 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( guarded_ptr&, Q const&)"
715 but \p pred is used for comparing the keys.
717 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
719 \p pred must imply the same element order as the comparator used for building the set.
721 template <typename Q, typename Less>
722 bool get_with( guarded_ptr& ptr, Q const& key, Less pred )
724 return get_with_( ptr.guard(), key, pred );
727 /// Clears the set (not atomic)
733 /// Checks if the set is empty
735 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
736 Thus, the correct item counting feature is an important part of split-list set implementation.
740 return base_class::empty();
743 /// Returns item count in the set
746 return base_class::size();
749 /// Returns internal statistics
750 stat const& statistics() const
752 return base_class::statistics();
757 using base_class::extract_;
758 using base_class::get_;
760 template <typename Q, typename Less>
761 bool extract_with_( typename gc::Guard& guard, Q const& key, Less pred )
763 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
766 template <typename Q, typename Less>
767 bool get_with_( typename gc::Guard& guard, Q const& key, Less pred )
769 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
777 }} // namespace cds::container
779 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_SET_H