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
157 typedef typename maker::cxx_node_allocator cxx_node_allocator;
158 typedef typename maker::node_type node_type;
163 typedef typename gc::template guarded_ptr< 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 )
194 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(),
195 [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
198 struct node_disposer {
199 void operator()( node_type * pNode )
204 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
206 bool insert_node( node_type * pNode )
208 assert( pNode != nullptr );
209 scoped_node_ptr p(pNode);
211 if ( base_class::insert( *pNode ) ) {
223 \p IsConst - constness boolean flag
225 The forward iterator for a split-list has the following features:
226 - it has no post-increment operator
227 - it depends on underlying ordered list iterator
228 - The iterator object cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
229 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
230 deleting operations it is no guarantee that you iterate all item in the split-list.
232 Therefore, the use of iterators in concurrent environment is not good idea. Use it for debug purpose only.
234 template <bool IsConst>
235 class iterator_type: protected base_class::template iterator_type<IsConst>
238 typedef typename base_class::template iterator_type<IsConst> iterator_base_class;
239 friend class SplitListSet;
242 /// Value pointer type (const for const iterator)
243 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
244 /// Value reference type (const for const iterator)
245 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
253 iterator_type( iterator_type const& src )
254 : iterator_base_class( src )
259 explicit iterator_type( iterator_base_class const& src )
260 : iterator_base_class( src )
265 /// Dereference operator
266 value_ptr operator ->() const
268 return &(iterator_base_class::operator->()->m_Value);
271 /// Dereference operator
272 value_ref operator *() const
274 return iterator_base_class::operator*().m_Value;
278 iterator_type& operator ++()
280 iterator_base_class::operator++();
284 /// Assignment operator
285 iterator_type& operator = (iterator_type const& src)
287 iterator_base_class::operator=(src);
291 /// Equality operator
293 bool operator ==(iterator_type<C> const& i ) const
295 return iterator_base_class::operator==(i);
298 /// Equality operator
300 bool operator !=(iterator_type<C> const& i ) const
302 return iterator_base_class::operator!=(i);
307 /// Initializes split-ordered list of default capacity
309 The default capacity is defined in bucket table constructor.
310 See \p intrusive::split_list::expandable_bucket_table, \p intrusive::split_list::static_bucket_table
311 which selects by \p split_list::dynamic_bucket_table option.
317 /// Initializes split-ordered list
319 size_t nItemCount ///< estimated average of item count
320 , size_t nLoadFactor = 1 ///< the load factor - average item count per bucket. Small integer up to 8, default is 1.
322 : base_class( nItemCount, nLoadFactor )
327 typedef iterator_type<false> iterator;
329 /// Const forward iterator
330 typedef iterator_type<true> const_iterator;
332 /// Returns a forward iterator addressing the first element in a set
334 For empty set \code begin() == end() \endcode
338 return iterator( base_class::begin() );
341 /// Returns an iterator that addresses the location succeeding the last element in a set
343 Do not use the value returned by <tt>end</tt> function to access any item.
344 The returned value can be used only to control reaching the end of the set.
345 For empty set \code begin() == end() \endcode
349 return iterator( base_class::end() );
352 /// Returns a forward const iterator addressing the first element in a set
353 const_iterator begin() const
357 /// Returns a forward const iterator addressing the first element in a set
358 const_iterator cbegin() const
360 return const_iterator( base_class::cbegin() );
363 /// Returns an const iterator that addresses the location succeeding the last element in a set
364 const_iterator end() const
368 /// Returns an const iterator that addresses the location succeeding the last element in a set
369 const_iterator cend() const
371 return const_iterator( base_class::cend() );
377 The function creates a node with copy of \p val value
378 and then inserts the node created into the set.
380 The type \p Q should contain as minimum the complete key for the node.
381 The object of \ref value_type should be constructible from a value of type \p Q.
382 In trivial case, \p Q is equal to \ref value_type.
384 Returns \p true if \p val is inserted into the set, \p false otherwise.
386 template <typename Q>
387 bool insert( Q const& val )
389 return insert_node( alloc_node( val ) );
394 The function allows to split creating of new item into two part:
395 - create item with key only
396 - insert new item into the set
397 - if inserting is success, calls \p f functor to initialize value-field of \p val.
399 The functor signature is:
401 void func( value_type& val );
403 where \p val is the item inserted.
405 The user-defined functor is called only if the inserting is success.
407 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
408 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
411 template <typename Q, typename Func>
412 bool insert( Q const& val, Func f )
414 scoped_node_ptr pNode( alloc_node( val ));
416 if ( base_class::insert( *pNode, [&f](node_type& node) { f( node.m_Value ) ; } )) {
423 /// Inserts data of type \p value_type created from \p args
425 Returns \p true if inserting successful, \p false otherwise.
427 template <typename... Args>
428 bool emplace( Args&&... args )
430 return insert_node( alloc_node( std::forward<Args>(args)...));
435 The operation performs inserting or changing data with lock-free manner.
437 If \p key is not found in the set, then \p key is inserted iff \p bAllowInsert is \p true.
438 Otherwise, the functor \p func is called with item found.
440 The functor signature is:
443 void operator()( bool bNew, value_type& item, const Q& val );
447 - \p bNew - \p true if the item has been inserted, \p false otherwise
448 - \p item - item of the set
449 - \p val - argument \p val passed into the \p %update() function
451 The functor may change non-key fields of the \p item.
453 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
454 \p second is true if new item has been added or \p false if the item with \p key
455 already is in the map.
457 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
458 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
461 template <typename Q, typename Func>
462 std::pair<bool, bool> update( Q const& val, Func func, bool bAllowInsert = true )
464 scoped_node_ptr pNode( alloc_node( val ));
466 std::pair<bool, bool> bRet = base_class::update( *pNode,
467 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
468 func( bNew, item.m_Value, val );
471 if ( bRet.first && bRet.second )
476 template <typename Q, typename Func>
477 CDS_DEPRECATED("ensure() is deprecated, use update()")
478 std::pair<bool, bool> ensure( Q const& val, Func func )
480 return update( val, func, true );
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 /// Checks whether the set contains \p key
664 The function searches the item with key equal to \p key
665 and returns \p true if it is found, and \p false otherwise.
667 Note the hash functor specified for class \p Traits template parameter
668 should accept a parameter of type \p Q that can be not the same as \p value_type.
669 Otherwise, you may use \p contains( Q const&, Less pred ) functions with explicit predicate for key comparing.
671 template <typename Q>
672 bool contains( Q const& key )
674 return base_class::contains( key );
677 template <typename Q>
678 CDS_DEPRECATED("deprecated, use contains()")
679 bool find( Q const& key )
681 return contains( key );
685 /// Checks whether the map contains \p key using \p pred predicate for searching
687 The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
688 \p Less functor has the interface like \p std::less.
689 \p Less must imply the same element order as the comparator used for building the map.
691 template <typename Q, typename Less>
692 bool contains( Q const& key, Less pred )
695 return base_class::contains( key, typename maker::template predicate_wrapper<Less>::type() );
698 template <typename Q, typename Less>
699 CDS_DEPRECATED("deprecated, use contains()")
700 bool find_with( Q const& key, Less pred )
702 return contains( key, pred );
706 /// Finds the key \p key and return the item found
707 /** \anchor cds_nonintrusive_SplitListSet_hp_get
708 The function searches the item with key equal to \p key
709 and returns the item found as \p guarded_ptr.
710 If \p key is not found the function returns an empty guarded pointer.
712 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
716 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
717 splitlist_set theSet;
720 splitlist_set::guarded_ptr gp(theSet.get( 5 ));
725 // Destructor of guarded_ptr releases internal HP guard
729 Note the compare functor specified for split-list set
730 should accept a parameter of type \p Q that can be not the same as \p value_type.
732 template <typename Q>
733 guarded_ptr get( Q const& key )
736 get_( gp.guard(), key );
740 /// Finds \p key and return the item found
742 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( Q const&)"
743 but \p pred is used for comparing the keys.
745 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
747 \p pred must imply the same element order as the comparator used for building the set.
749 template <typename Q, typename Less>
750 guarded_ptr get_with( Q const& key, Less pred )
753 get_with_( gp.guard(), key, pred );
757 /// Clears the set (not atomic)
763 /// Checks if the set is empty
765 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
766 Thus, the correct item counting feature is an important part of split-list set implementation.
770 return base_class::empty();
773 /// Returns item count in the set
776 return base_class::size();
779 /// Returns internal statistics
780 stat const& statistics() const
782 return base_class::statistics();
787 using base_class::extract_;
788 using base_class::get_;
790 template <typename Q, typename Less>
791 bool extract_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
794 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
797 template <typename Q, typename Less>
798 bool get_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
801 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
809 }} // namespace cds::container
811 #endif // #ifndef CDSLIB_CONTAINER_SPLIT_LIST_SET_H