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
156 typedef typename maker::cxx_node_allocator cxx_node_allocator;
157 typedef typename maker::node_type node_type;
162 typedef cds::gc::guarded_ptr< gc, node_type, value_type, details::guarded_ptr_cast_set<node_type, value_type> > guarded_ptr;
166 template <typename Q>
167 static node_type * alloc_node(Q const& v )
169 return cxx_node_allocator().New( v );
172 template <typename... Args>
173 static node_type * alloc_node( Args&&... args )
175 return cxx_node_allocator().MoveNew( std::forward<Args>( args )... );
178 static void free_node( node_type * pNode )
180 cxx_node_allocator().Delete( pNode );
183 template <typename Q, typename Func>
184 bool find_( Q& val, Func f )
186 return base_class::find( val, [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
189 template <typename Q, typename Less, typename Func>
190 bool find_with_( Q& val, Less pred, Func f )
192 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(),
193 [&f]( node_type& item, Q& val ) { f(item.m_Value, val) ; } );
196 struct node_disposer {
197 void operator()( node_type * pNode )
202 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
204 bool insert_node( node_type * pNode )
206 assert( pNode != nullptr );
207 scoped_node_ptr p(pNode);
209 if ( base_class::insert( *pNode ) ) {
221 \p IsConst - constness boolean flag
223 The forward iterator for a split-list has the following features:
224 - it has no post-increment operator
225 - it depends on underlying ordered list iterator
226 - The iterator object cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
227 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
228 deleting operations it is no guarantee that you iterate all item in the split-list.
230 Therefore, the use of iterators in concurrent environment is not good idea. Use it for debug purpose only.
232 template <bool IsConst>
233 class iterator_type: protected base_class::template iterator_type<IsConst>
236 typedef typename base_class::template iterator_type<IsConst> iterator_base_class;
237 friend class SplitListSet;
240 /// Value pointer type (const for const iterator)
241 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
242 /// Value reference type (const for const iterator)
243 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
251 iterator_type( iterator_type const& src )
252 : iterator_base_class( src )
257 explicit iterator_type( iterator_base_class const& src )
258 : iterator_base_class( src )
263 /// Dereference operator
264 value_ptr operator ->() const
266 return &(iterator_base_class::operator->()->m_Value);
269 /// Dereference operator
270 value_ref operator *() const
272 return iterator_base_class::operator*().m_Value;
276 iterator_type& operator ++()
278 iterator_base_class::operator++();
282 /// Assignment operator
283 iterator_type& operator = (iterator_type const& src)
285 iterator_base_class::operator=(src);
289 /// Equality operator
291 bool operator ==(iterator_type<C> const& i ) const
293 return iterator_base_class::operator==(i);
296 /// Equality operator
298 bool operator !=(iterator_type<C> const& i ) const
300 return iterator_base_class::operator!=(i);
305 /// Initializes split-ordered list of default capacity
307 The default capacity is defined in bucket table constructor.
308 See \p intrusive::split_list::expandable_bucket_table, \p intrusive::split_list::static_bucket_table
309 which selects by \p split_list::dynamic_bucket_table option.
315 /// Initializes split-ordered list
317 size_t nItemCount ///< estimated average of item count
318 , size_t nLoadFactor = 1 ///< the load factor - average item count per bucket. Small integer up to 8, default is 1.
320 : base_class( nItemCount, nLoadFactor )
325 typedef iterator_type<false> iterator;
327 /// Const forward iterator
328 typedef iterator_type<true> const_iterator;
330 /// Returns a forward iterator addressing the first element in a set
332 For empty set \code begin() == end() \endcode
336 return iterator( base_class::begin() );
339 /// Returns an iterator that addresses the location succeeding the last element in a set
341 Do not use the value returned by <tt>end</tt> function to access any item.
342 The returned value can be used only to control reaching the end of the set.
343 For empty set \code begin() == end() \endcode
347 return iterator( base_class::end() );
350 /// Returns a forward const iterator addressing the first element in a set
351 const_iterator begin() const
353 return const_iterator( base_class::begin() );
356 /// Returns an const iterator that addresses the location succeeding the last element in a set
357 const_iterator end() const
359 return const_iterator( base_class::end() );
365 The function creates a node with copy of \p val value
366 and then inserts the node created into the set.
368 The type \p Q should contain as minimum the complete key for the node.
369 The object of \ref value_type should be constructible from a value of type \p Q.
370 In trivial case, \p Q is equal to \ref value_type.
372 Returns \p true if \p val is inserted into the set, \p false otherwise.
374 template <typename Q>
375 bool insert( Q const& val )
377 return insert_node( alloc_node( val ) );
382 The function allows to split creating of new item into two part:
383 - create item with key only
384 - insert new item into the set
385 - if inserting is success, calls \p f functor to initialize value-field of \p val.
387 The functor signature is:
389 void func( value_type& val );
391 where \p val is the item inserted.
393 The user-defined functor is called only if the inserting is success.
395 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
396 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
399 template <typename Q, typename Func>
400 bool insert( Q const& val, Func f )
402 scoped_node_ptr pNode( alloc_node( val ));
404 if ( base_class::insert( *pNode, [&f](node_type& node) { f( node.m_Value ) ; } )) {
411 /// Inserts data of type \p value_type created from \p args
413 Returns \p true if inserting successful, \p false otherwise.
415 template <typename... Args>
416 bool emplace( Args&&... args )
418 return insert_node( alloc_node( std::forward<Args>(args)...));
421 /// Ensures that the \p item exists in the set
423 The operation performs inserting or changing data with lock-free manner.
425 If the \p val key not found in the set, then the new item created from \p val
426 is inserted into the set. Otherwise, the functor \p func is called with the item found.
427 The functor \p Func should be a function with signature:
429 void func( bool bNew, value_type& item, const Q& val );
434 void operator()( bool bNew, value_type& item, const Q& val );
439 - \p bNew - \p true if the item has been inserted, \p false otherwise
440 - \p item - item of the set
441 - \p val - argument \p val passed into the \p ensure function
443 The functor may change non-key fields of the \p item.
445 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
446 \p second is true if new item has been added or \p false if the item with \p key
447 already is in the set.
449 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
450 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
453 template <typename Q, typename Func>
454 std::pair<bool, bool> ensure( Q const& val, Func func )
456 scoped_node_ptr pNode( alloc_node( val ));
458 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
459 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
460 func( bNew, item.m_Value, val );
463 if ( bRet.first && bRet.second )
468 /// Deletes \p key from the set
469 /** \anchor cds_nonintrusive_SplitListSet_erase_val
471 The item comparator should be able to compare the values of type \p value_type
474 Return \p true if key is found and deleted, \p false otherwise
476 template <typename Q>
477 bool erase( Q const& key )
479 return base_class::erase( key );
482 /// Deletes the item from the set using \p pred predicate for searching
484 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
485 but \p pred is used for key comparing.
486 \p Less functor has the interface like \p std::less.
487 \p Less must imply the same element order as the comparator used for building the set.
489 template <typename Q, typename Less>
490 bool erase_with( Q const& key, Less pred )
492 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
495 /// Deletes \p key from the set
496 /** \anchor cds_nonintrusive_SplitListSet_erase_func
498 The function searches an item with key \p key, calls \p f functor
499 and deletes the item. If \p key is not found, the functor is not called.
501 The functor \p Func interface:
504 void operator()(value_type const& val);
508 Since the key of split-list \p value_type is not explicitly specified,
509 template parameter \p Q defines the key type searching in the list.
510 The list item comparator should be able to compare the values of the type \p value_type
513 Return \p true if key is found and deleted, \p false otherwise
515 template <typename Q, typename Func>
516 bool erase( Q const& key, Func f )
518 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
521 /// Deletes the item from the set using \p pred predicate for searching
523 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
524 but \p pred is used for key comparing.
525 \p Less functor has the interface like \p std::less.
526 \p Less must imply the same element order as the comparator used for building the set.
528 template <typename Q, typename Less, typename Func>
529 bool erase_with( Q const& key, Less pred, Func f )
531 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
532 [&f](node_type& node) { f( node.m_Value ); } );
535 /// Extracts the item with specified \p key
536 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
537 The function searches an item with key equal to \p key,
538 unlinks it from the set, and returns it in \p dest parameter.
539 If the item with key equal to \p key is not found the function returns \p false.
541 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
543 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
544 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
548 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
549 splitlist_set theSet;
552 splitlist_set::guarded_ptr gp;
553 theSet.extract( gp, 5 );
557 // Destructor of gp releases internal HP guard
561 template <typename Q>
562 bool extract( guarded_ptr& dest, Q const& key )
564 return extract_( dest.guard(), key );
567 /// Extracts the item using compare functor \p pred
569 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(guarded_ptr&, Q const&)"
570 but \p pred predicate is used for key comparing.
572 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
574 \p pred must imply the same element order as the comparator used for building the set.
576 template <typename Q, typename Less>
577 bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
579 return extract_with_( dest.guard(), key, pred );
582 /// Finds the key \p key
583 /** \anchor cds_nonintrusive_SplitListSet_find_func
585 The function searches the item with key equal to \p key and calls the functor \p f for item found.
586 The interface of \p Func functor is:
589 void operator()( value_type& item, Q& key );
592 where \p item is the item found, \p key is the <tt>find</tt> function argument.
594 You may pass \p f argument by reference using \p std::ref.
596 The functor may change non-key fields of \p item. Note that the functor is only guarantee
597 that \p item cannot be disposed during functor is executing.
598 The functor does not serialize simultaneous access to the set's \p item. If such access is
599 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
601 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
602 may modify both arguments.
604 Note the hash functor specified for class \p Traits template parameter
605 should accept a parameter of type \p Q that can be not the same as \p value_type.
607 The function returns \p true if \p key is found, \p false otherwise.
609 template <typename Q, typename Func>
610 bool find( Q& key, Func f )
612 return find_( key, f );
615 /// Finds the key \p key using \p pred predicate for searching
617 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
618 but \p pred is used for key comparing.
619 \p Less functor has the interface like \p std::less.
620 \p Less must imply the same element order as the comparator used for building the set.
622 template <typename Q, typename Less, typename Func>
623 bool find_with( Q& key, Less pred, Func f )
625 return find_with_( key, pred, f );
628 /// Finds the key \p key
629 /** \anchor cds_nonintrusive_SplitListSet_find_val
631 The function searches the item with key equal to \p key
632 and returns \p true if it is found, and \p false otherwise.
634 Note the hash functor specified for class \p Traits template parameter
635 should accept a parameter of type \p Q that can be not the same as \ref value_type.
637 template <typename Q>
638 bool find( Q const& key )
640 return base_class::find( key );
643 /// Finds the key \p key using \p pred predicate for searching
645 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
646 but \p pred is used for key comparing.
647 \p Less functor has the interface like \p std::less.
648 \p Less must imply the same element order as the comparator used for building the set.
650 template <typename Q, typename Less>
651 bool find_with( Q const& key, Less pred )
653 return base_class::find_with( key, typename maker::template predicate_wrapper<Less>::type() );
656 /// Finds the key \p key and return the item found
657 /** \anchor cds_nonintrusive_SplitListSet_hp_get
658 The function searches the item with key equal to \p key
659 and assigns the item found to guarded pointer \p ptr.
660 The function returns \p true if \p key is found, and \p false otherwise.
661 If \p key is not found the \p ptr parameter is not changed.
663 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
667 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
668 splitlist_set theSet;
671 splitlist_set::guarded_ptr gp;
672 if ( theSet.get( gp, 5 )) {
676 // Destructor of guarded_ptr releases internal HP guard
680 Note the compare functor specified for split-list set
681 should accept a parameter of type \p Q that can be not the same as \p value_type.
683 template <typename Q>
684 bool get( guarded_ptr& ptr, Q const& key )
686 return get_( ptr.guard(), key );
689 /// Finds \p key and return the item found
691 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( guarded_ptr&, Q const&)"
692 but \p pred is used for comparing the keys.
694 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
696 \p pred must imply the same element order as the comparator used for building the set.
698 template <typename Q, typename Less>
699 bool get_with( guarded_ptr& ptr, Q const& key, Less pred )
701 return get_with_( ptr.guard(), key, pred );
704 /// Clears the set (not atomic)
710 /// Checks if the set is empty
712 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
713 Thus, the correct item counting feature is an important part of split-list set implementation.
717 return base_class::empty();
720 /// Returns item count in the set
723 return base_class::size();
728 using base_class::extract_;
729 using base_class::get_;
731 template <typename Q, typename Less>
732 bool extract_with_( typename gc::Guard& guard, Q const& key, Less pred )
734 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
737 template <typename Q, typename Less>
738 bool get_with_( typename gc::Guard& guard, Q const& key, Less pred )
740 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
748 }} // namespace cds::container
750 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_SET_H