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::PTB, 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::PTB // 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
354 return const_iterator( base_class::begin() );
357 /// Returns an const iterator that addresses the location succeeding the last element in a set
358 const_iterator end() const
360 return const_iterator( base_class::end() );
366 The function creates a node with copy of \p val value
367 and then inserts the node created into the set.
369 The type \p Q should contain as minimum the complete key for the node.
370 The object of \ref value_type should be constructible from a value of type \p Q.
371 In trivial case, \p Q is equal to \ref value_type.
373 Returns \p true if \p val is inserted into the set, \p false otherwise.
375 template <typename Q>
376 bool insert( Q const& val )
378 return insert_node( alloc_node( val ) );
383 The function allows to split creating of new item into two part:
384 - create item with key only
385 - insert new item into the set
386 - if inserting is success, calls \p f functor to initialize value-field of \p val.
388 The functor signature is:
390 void func( value_type& val );
392 where \p val is the item inserted.
394 The user-defined functor is called only if the inserting is success.
396 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
397 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
400 template <typename Q, typename Func>
401 bool insert( Q const& val, Func f )
403 scoped_node_ptr pNode( alloc_node( val ));
405 if ( base_class::insert( *pNode, [&f](node_type& node) { f( node.m_Value ) ; } )) {
412 /// Inserts data of type \p value_type created from \p args
414 Returns \p true if inserting successful, \p false otherwise.
416 template <typename... Args>
417 bool emplace( Args&&... args )
419 return insert_node( alloc_node( std::forward<Args>(args)...));
422 /// Ensures that the \p item exists in the set
424 The operation performs inserting or changing data with lock-free manner.
426 If the \p val key not found in the set, then the new item created from \p val
427 is inserted into the set. Otherwise, the functor \p func is called with the item found.
428 The functor \p Func should be a function with signature:
430 void func( bool bNew, value_type& item, const Q& val );
435 void operator()( bool bNew, value_type& item, const Q& val );
440 - \p bNew - \p true if the item has been inserted, \p false otherwise
441 - \p item - item of the set
442 - \p val - argument \p val passed into the \p ensure function
444 The functor may change non-key fields of the \p item.
446 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
447 \p second is true if new item has been added or \p false if the item with \p key
448 already is in the set.
450 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
451 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
454 template <typename Q, typename Func>
455 std::pair<bool, bool> ensure( Q const& val, Func func )
457 scoped_node_ptr pNode( alloc_node( val ));
459 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
460 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
461 func( bNew, item.m_Value, val );
464 if ( bRet.first && bRet.second )
469 /// Deletes \p key from the set
470 /** \anchor cds_nonintrusive_SplitListSet_erase_val
472 The item comparator should be able to compare the values of type \p value_type
475 Return \p true if key is found and deleted, \p false otherwise
477 template <typename Q>
478 bool erase( Q const& key )
480 return base_class::erase( key );
483 /// Deletes the item from the set using \p pred predicate for searching
485 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
486 but \p pred is used for key comparing.
487 \p Less functor has the interface like \p std::less.
488 \p Less must imply the same element order as the comparator used for building the set.
490 template <typename Q, typename Less>
491 bool erase_with( Q const& key, Less pred )
493 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
496 /// Deletes \p key from the set
497 /** \anchor cds_nonintrusive_SplitListSet_erase_func
499 The function searches an item with key \p key, calls \p f functor
500 and deletes the item. If \p key is not found, the functor is not called.
502 The functor \p Func interface:
505 void operator()(value_type const& val);
509 Since the key of split-list \p value_type is not explicitly specified,
510 template parameter \p Q defines the key type searching in the list.
511 The list item comparator should be able to compare the values of the type \p value_type
514 Return \p true if key is found and deleted, \p false otherwise
516 template <typename Q, typename Func>
517 bool erase( Q const& key, Func f )
519 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
522 /// Deletes the item from the set using \p pred predicate for searching
524 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
525 but \p pred is used for key comparing.
526 \p Less functor has the interface like \p std::less.
527 \p Less must imply the same element order as the comparator used for building the set.
529 template <typename Q, typename Less, typename Func>
530 bool erase_with( Q const& key, Less pred, Func f )
532 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
533 [&f](node_type& node) { f( node.m_Value ); } );
536 /// Extracts the item with specified \p key
537 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
538 The function searches an item with key equal to \p key,
539 unlinks it from the set, and returns it in \p dest parameter.
540 If the item with key equal to \p key is not found the function returns \p false.
542 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
544 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
545 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
549 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
550 splitlist_set theSet;
553 splitlist_set::guarded_ptr gp;
554 theSet.extract( gp, 5 );
558 // Destructor of gp releases internal HP guard
562 template <typename Q>
563 bool extract( guarded_ptr& dest, Q const& key )
565 return extract_( dest.guard(), key );
568 /// Extracts the item using compare functor \p pred
570 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(guarded_ptr&, Q const&)"
571 but \p pred predicate is used for key comparing.
573 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
575 \p pred must imply the same element order as the comparator used for building the set.
577 template <typename Q, typename Less>
578 bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
580 return extract_with_( dest.guard(), key, pred );
583 /// Finds the key \p key
584 /** \anchor cds_nonintrusive_SplitListSet_find_func
586 The function searches the item with key equal to \p key and calls the functor \p f for item found.
587 The interface of \p Func functor is:
590 void operator()( value_type& item, Q& key );
593 where \p item is the item found, \p key is the <tt>find</tt> function argument.
595 You may pass \p f argument by reference using \p std::ref.
597 The functor may change non-key fields of \p item. Note that the functor is only guarantee
598 that \p item cannot be disposed during functor is executing.
599 The functor does not serialize simultaneous access to the set's \p item. If such access is
600 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
602 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
603 may modify both arguments.
605 Note the hash functor specified for class \p Traits template parameter
606 should accept a parameter of type \p Q that can be not the same as \p value_type.
608 The function returns \p true if \p key is found, \p false otherwise.
610 template <typename Q, typename Func>
611 bool find( Q& key, Func f )
613 return find_( key, f );
616 /// Finds the key \p key using \p pred predicate for searching
618 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
619 but \p pred is used for key comparing.
620 \p Less functor has the interface like \p std::less.
621 \p Less must imply the same element order as the comparator used for building the set.
623 template <typename Q, typename Less, typename Func>
624 bool find_with( Q& key, Less pred, Func f )
626 return find_with_( key, pred, f );
629 /// Finds the key \p key
630 /** \anchor cds_nonintrusive_SplitListSet_find_val
632 The function searches the item with key equal to \p key
633 and returns \p true if it is found, and \p false otherwise.
635 Note the hash functor specified for class \p Traits template parameter
636 should accept a parameter of type \p Q that can be not the same as \ref value_type.
638 template <typename Q>
639 bool find( Q const& key )
641 return base_class::find( key );
644 /// Finds the key \p key using \p pred predicate for searching
646 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
647 but \p pred is used for key comparing.
648 \p Less functor has the interface like \p std::less.
649 \p Less must imply the same element order as the comparator used for building the set.
651 template <typename Q, typename Less>
652 bool find_with( Q const& key, Less pred )
654 return base_class::find_with( key, typename maker::template predicate_wrapper<Less>::type() );
657 /// Finds the key \p key and return the item found
658 /** \anchor cds_nonintrusive_SplitListSet_hp_get
659 The function searches the item with key equal to \p key
660 and assigns the item found to guarded pointer \p ptr.
661 The function returns \p true if \p key is found, and \p false otherwise.
662 If \p key is not found the \p ptr parameter is not changed.
664 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
668 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
669 splitlist_set theSet;
672 splitlist_set::guarded_ptr gp;
673 if ( theSet.get( gp, 5 )) {
677 // Destructor of guarded_ptr releases internal HP guard
681 Note the compare functor specified for split-list set
682 should accept a parameter of type \p Q that can be not the same as \p value_type.
684 template <typename Q>
685 bool get( guarded_ptr& ptr, Q const& key )
687 return get_( ptr.guard(), key );
690 /// Finds \p key and return the item found
692 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( guarded_ptr&, Q const&)"
693 but \p pred is used for comparing the keys.
695 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
697 \p pred must imply the same element order as the comparator used for building the set.
699 template <typename Q, typename Less>
700 bool get_with( guarded_ptr& ptr, Q const& key, Less pred )
702 return get_with_( ptr.guard(), key, pred );
705 /// Clears the set (not atomic)
711 /// Checks if the set is empty
713 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
714 Thus, the correct item counting feature is an important part of split-list set implementation.
718 return base_class::empty();
721 /// Returns item count in the set
724 return base_class::size();
727 /// Returns internal statistics
728 stat const& statistics() const
730 return base_class::statistics();
735 using base_class::extract_;
736 using base_class::get_;
738 template <typename Q, typename Less>
739 bool extract_with_( typename gc::Guard& guard, Q const& key, Less pred )
741 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
744 template <typename Q, typename Less>
745 bool get_with_( typename gc::Guard& guard, Q const& key, Less pred )
747 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
755 }} // namespace cds::container
757 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_SET_H