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>
8 #include <cds/details/functor_wrapper.h>
10 namespace cds { namespace container {
12 /// Split-ordered list set
13 /** @ingroup cds_nonintrusive_set
14 \anchor cds_nonintrusive_SplitListSet_hp
16 Hash table implementation based on split-ordered list algorithm discovered by Ori Shalev and Nir Shavit, see
17 - [2003] Ori Shalev, Nir Shavit "Split-Ordered Lists - Lock-free Resizable Hash Tables"
18 - [2008] Nir Shavit "The Art of Multiprocessor Programming"
20 See intrusive::SplitListSet for a brief description of the split-list algorithm.
23 - \p GC - Garbage collector used
24 - \p T - type stored in the split-list. The type must be default- and copy-constructible.
25 - \p Traits - type traits, default is split_list::type_traits. Instead of declaring split_list::type_traits -based
26 struct you may apply option-based notation with split_list::make_traits metafunction.
28 There are the specializations:
29 - for \ref cds_urcu_desc "RCU" - declared in <tt>cd/container/split_list_set_rcu.h</tt>,
30 see \ref cds_nonintrusive_SplitListSet_rcu "SplitListSet<RCU>".
31 - for \ref cds::gc::nogc declared in <tt>cds/container/split_list_set_nogc.h</tt>,
32 see \ref cds_nonintrusive_SplitListSet_nogc "SplitListSet<gc::nogc>".
36 You should decide what garbage collector you want, and what ordered list you want to use. Split-ordered list
37 is original data structure based on an ordered list. Suppose, you want construct split-list set based on gc::PTB GC
38 and LazyList as ordered list implementation. So, you beginning your program with following include:
40 #include <cds/container/lazy_list_ptb.h>
41 #include <cds/container/split_list_set.h>
43 namespace cc = cds::container;
45 // The data belonged to split-ordered list
47 int nKey; // key field
48 std::string strValue ; // value field
51 The inclusion order is important: first, include header for ordered-list implementation (for this example, <tt>cds/container/lazy_list_ptb.h</tt>),
52 then the header for split-list set <tt>cds/container/split_list_set.h</tt>.
54 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.
55 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
56 object by the key of type <tt>int</tt> and by the value of type <tt>foo</tt>.
58 The second attention: instead of using \p %LazyList in \p %SplitListSet traits we use a tag <tt>cds::contaner::lazy_list_tag</tt> for the lazy list.
59 The split-list requires significant support from underlying ordered list class and it is not good idea to dive you
60 into deep implementation details of split-list and ordered list interrelations. The tag paradigm simplifies split-list interface.
65 size_t operator()( int key ) const { return std::hash( key ) ; }
66 size_t operator()( foo const& item ) const { return std::hash( item.nKey ) ; }
71 bool operator()(int i, foo const& f ) const { return i < f.nKey ; }
72 bool operator()(foo const& f, int i ) const { return f.nKey < i ; }
73 bool operator()(foo const& f1, foo const& f2) const { return f1.nKey < f2.nKey; }
76 // SplitListSet traits
77 struct foo_set_traits: public cc::split_list::type_traits
79 typedef cc::lazy_list_tag ordered_list ; // what type of ordered list we want to use
80 typedef foo_hash hash ; // hash functor for our data stored in split-list set
82 // Type traits for our LazyList class
83 struct ordered_list_traits: public cc::lazy_list::type_traits
85 typedef foo_less less ; // use our foo_less as comparator to order list nodes
90 Now you are ready to declare our set class based on \p %SplitListSet:
92 typedef cc::SplitListSet< cds::gc::PTB, foo, foo_set_traits > foo_set;
95 You may use the modern option-based declaration instead of classic type-traits-based one:
97 typedef cc:SplitListSet<
98 cs::gc::PTB // GC used
99 ,foo // type of data stored
100 ,cc::split_list::make_traits< // metafunction to build split-list traits
101 cc::split_list::ordered_list<cc::lazy_list_tag> // tag for underlying ordered list implementation
102 ,cc::opt::hash< foo_hash > // hash functor
103 ,cc::split_list::ordered_list_traits< // ordered list traits desired
104 cc::lazy_list::make_traits< // metafunction to build lazy list traits
105 cc::opt::less< foo_less > // less-based compare functor
111 In case of option-based declaration using split_list::make_traits metafunction
112 the struct \p foo_set_traits is not required.
114 Now, the set of type \p foo_set is ready to use in your program.
116 Note that in this example we show only mandatory type_traits parts, optional ones is the default and they are inherited
117 from cds::container::split_list::type_traits.
118 The <b>cds</b> library contains many other options for deep tuning of behavior of the split-list and
119 ordered-list containers.
124 #ifdef CDS_DOXYGEN_INVOKED
125 class Traits = split_list::type_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 Traits options ; ///< \p Traits template argument
145 typedef typename maker::gc gc ; ///< Garbage collector
146 typedef typename maker::value_type value_type ; ///< type of value stored in the list
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 Q, typename Func>
173 bool find_( Q& val, Func f )
175 # ifdef CDS_CXX11_LAMBDA_SUPPORT
176 return base_class::find( val, [&f]( node_type& item, Q& val ) { cds::unref(f)(item.m_Value, val) ; } );
178 find_functor_wrapper<Func> fw(f);
179 return base_class::find( val, cds::ref(fw) );
183 template <typename Q, typename Less, typename Func>
184 bool find_with_( Q& val, Less pred, Func f )
186 # ifdef CDS_CXX11_LAMBDA_SUPPORT
187 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(),
188 [&f]( node_type& item, Q& val ) { cds::unref(f)(item.m_Value, val) ; } );
190 find_functor_wrapper<Func> fw(f);
191 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type(), cds::ref(fw) );
195 template <typename... Args>
196 static node_type * alloc_node( Args&&... args )
198 return cxx_node_allocator().MoveNew( std::forward<Args>(args)...);
201 static void free_node( node_type * pNode )
203 cxx_node_allocator().Delete( pNode );
206 struct node_disposer {
207 void operator()( node_type * pNode )
212 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
214 bool insert_node( node_type * pNode )
216 assert( pNode != nullptr );
217 scoped_node_ptr p(pNode);
219 if ( base_class::insert( *pNode ) ) {
231 # ifndef CDS_CXX11_LAMBDA_SUPPORT
232 template <typename Func>
233 class insert_functor_wrapper: protected cds::details::functor_wrapper<Func>
235 typedef cds::details::functor_wrapper<Func> base_class;
237 insert_functor_wrapper( Func f ): base_class(f) {}
239 void operator()(node_type& node)
241 base_class::get()( node.m_Value );
245 template <typename Func, typename Q>
246 class ensure_functor_wrapper: protected cds::details::functor_wrapper<Func>
248 typedef cds::details::functor_wrapper<Func> base_class;
251 ensure_functor_wrapper( Func f, Q const& v ): base_class(f), m_val(v) {}
253 void operator()( bool bNew, node_type& item, node_type const& /*val*/ )
255 base_class::get()( bNew, item.m_Value, m_val );
259 template <typename Func>
260 class find_functor_wrapper: protected cds::details::functor_wrapper<Func>
262 typedef cds::details::functor_wrapper<Func> base_class;
264 find_functor_wrapper( Func f ): base_class(f) {}
266 template <typename Q>
267 void operator()( node_type& item, Q& val )
269 base_class::get()( item.m_Value, val );
273 template <typename Func>
274 class erase_functor_wrapper: protected cds::details::functor_wrapper<Func>
276 typedef cds::details::functor_wrapper<Func> base_class;
278 erase_functor_wrapper( Func f ): base_class( f ) {}
280 void operator()(node_type& node)
282 base_class::get()( node.m_Value );
285 # endif // ifndef CDS_CXX11_LAMBDA_SUPPORT
291 \p IsConst - constness boolean flag
293 The forward iterator for a split-list has the following features:
294 - it has no post-increment operator
295 - it depends on underlying ordered list iterator
296 - The iterator object cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
297 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
298 deleting operations it is no guarantee that you iterate all item in the split-list.
300 Therefore, the use of iterators in concurrent environment is not good idea. Use it for debug purpose only.
302 template <bool IsConst>
303 class iterator_type: protected base_class::template iterator_type<IsConst>
306 typedef typename base_class::template iterator_type<IsConst> iterator_base_class;
307 friend class SplitListSet;
310 /// Value pointer type (const for const iterator)
311 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
312 /// Value reference type (const for const iterator)
313 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
321 iterator_type( iterator_type const& src )
322 : iterator_base_class( src )
327 explicit iterator_type( iterator_base_class const& src )
328 : iterator_base_class( src )
333 /// Dereference operator
334 value_ptr operator ->() const
336 return &(iterator_base_class::operator->()->m_Value);
339 /// Dereference operator
340 value_ref operator *() const
342 return iterator_base_class::operator*().m_Value;
346 iterator_type& operator ++()
348 iterator_base_class::operator++();
352 /// Assignment operator
353 iterator_type& operator = (iterator_type const& src)
355 iterator_base_class::operator=(src);
359 /// Equality operator
361 bool operator ==(iterator_type<C> const& i ) const
363 return iterator_base_class::operator==(i);
366 /// Equality operator
368 bool operator !=(iterator_type<C> const& i ) const
370 return iterator_base_class::operator!=(i);
375 /// Initializes split-ordered list of default capacity
377 The default capacity is defined in bucket table constructor.
378 See intrusive::split_list::expandable_bucket_table, intrusive::split_list::static_bucket_table
379 which selects by intrusive::split_list::dynamic_bucket_table option.
385 /// Initializes split-ordered list
387 size_t nItemCount ///< estimate average of item count
388 , size_t nLoadFactor = 1 ///< load factor - average item count per bucket. Small integer up to 8, default is 1.
390 : base_class( nItemCount, nLoadFactor )
395 typedef iterator_type<false> iterator;
397 /// Const forward iterator
398 typedef iterator_type<true> const_iterator;
400 /// Returns a forward iterator addressing the first element in a set
402 For empty set \code begin() == end() \endcode
406 return iterator( base_class::begin() );
409 /// Returns an iterator that addresses the location succeeding the last element in a set
411 Do not use the value returned by <tt>end</tt> function to access any item.
412 The returned value can be used only to control reaching the end of the set.
413 For empty set \code begin() == end() \endcode
417 return iterator( base_class::end() );
420 /// Returns a forward const iterator addressing the first element in a set
421 const_iterator begin() const
423 return const_iterator( base_class::begin() );
426 /// Returns an const iterator that addresses the location succeeding the last element in a set
427 const_iterator end() const
429 return const_iterator( base_class::end() );
435 The function creates a node with copy of \p val value
436 and then inserts the node created into the set.
438 The type \p Q should contain as minimum the complete key for the node.
439 The object of \ref value_type should be constructible from a value of type \p Q.
440 In trivial case, \p Q is equal to \ref value_type.
442 Returns \p true if \p val is inserted into the set, \p false otherwise.
444 template <typename Q>
445 bool insert( Q const& val )
447 return insert_node( alloc_node( val ) );
452 The function allows to split creating of new item into two part:
453 - create item with key only
454 - insert new item into the set
455 - if inserting is success, calls \p f functor to initialize value-field of \p val.
457 The functor signature is:
459 void func( value_type& val );
461 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
462 \p val no any other changes could be made on this set's item by concurrent threads.
463 The user-defined functor is called only if the inserting is success. It may be passed by reference
464 using <tt>boost::ref</tt>
466 template <typename Q, typename Func>
467 bool insert( Q const& val, Func f )
469 scoped_node_ptr pNode( alloc_node( val ));
471 # ifdef CDS_CXX11_LAMBDA_SUPPORT
472 if ( base_class::insert( *pNode, [&f](node_type& node) { cds::unref(f)( node.m_Value ) ; } ))
474 insert_functor_wrapper<Func> fw(f);
475 if ( base_class::insert( *pNode, cds::ref(fw) ) )
484 /// Inserts data of type \p %value_type constructed with <tt>std::forward<Args>(args)...</tt>
486 Returns \p true if inserting successful, \p false otherwise.
488 template <typename... Args>
489 bool emplace( Args&&... args )
491 return insert_node( alloc_node( std::forward<Args>(args)...));
494 /// Ensures that the \p item exists in the set
496 The operation performs inserting or changing data with lock-free manner.
498 If the \p val key not found in the set, then the new item created from \p val
499 is inserted into the set. Otherwise, the functor \p func is called with the item found.
500 The functor \p Func should be a function with signature:
502 void func( bool bNew, value_type& item, const Q& val );
507 void operator()( bool bNew, value_type& item, const Q& val );
512 - \p bNew - \p true if the item has been inserted, \p false otherwise
513 - \p item - item of the set
514 - \p val - argument \p val passed into the \p ensure function
516 The functor may change non-key fields of the \p item; however, \p func must guarantee
517 that during changing no any other modifications could be made on this item by concurrent threads.
519 You may pass \p func argument by reference using <tt>boost::ref</tt>.
521 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
522 \p second is true if new item has been added or \p false if the item with \p key
523 already is in the set.
525 template <typename Q, typename Func>
526 std::pair<bool, bool> ensure( Q const& val, Func func )
528 scoped_node_ptr pNode( alloc_node( val ));
530 # ifdef CDS_CXX11_LAMBDA_SUPPORT
531 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
532 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
533 cds::unref(func)( bNew, item.m_Value, val );
536 ensure_functor_wrapper<Func, Q> fw( func, val );
537 std::pair<bool, bool> bRet = base_class::ensure( *pNode, cds::ref(fw) );
540 if ( bRet.first && bRet.second )
545 /// Deletes \p key from the set
546 /** \anchor cds_nonintrusive_SplitListSet_erase_val
548 The item comparator should be able to compare the values of type \p value_type
551 Return \p true if key is found and deleted, \p false otherwise
553 template <typename Q>
554 bool erase( Q const& key )
556 return base_class::erase( key );
559 /// Deletes the item from the set using \p pred predicate for searching
561 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
562 but \p pred is used for key comparing.
563 \p Less functor has the interface like \p std::less.
564 \p Less must imply the same element order as the comparator used for building the set.
566 template <typename Q, typename Less>
567 bool erase_with( Q const& key, Less pred )
569 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
572 /// Deletes \p key from the set
573 /** \anchor cds_nonintrusive_SplitListSet_erase_func
575 The function searches an item with key \p key, calls \p f functor
576 and deletes the item. If \p key is not found, the functor is not called.
578 The functor \p Func interface:
581 void operator()(value_type const& val);
584 The functor may be passed by reference using <tt>boost:ref</tt>
586 Since the key of SplitListSet's \p value_type is not explicitly specified,
587 template parameter \p Q defines the key type searching in the list.
588 The list item comparator should be able to compare the values of the type \p value_type
591 Return \p true if key is found and deleted, \p false otherwise
593 template <typename Q, typename Func>
594 bool erase( Q const& key, Func f )
596 # ifdef CDS_CXX11_LAMBDA_SUPPORT
597 return base_class::erase( key, [&f](node_type& node) { cds::unref(f)( node.m_Value ); } );
599 erase_functor_wrapper<Func> fw( f );
600 return base_class::erase( key, cds::ref(fw) );
604 /// Deletes the item from the set using \p pred predicate for searching
606 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
607 but \p pred is used for key comparing.
608 \p Less functor has the interface like \p std::less.
609 \p Less must imply the same element order as the comparator used for building the set.
611 template <typename Q, typename Less, typename Func>
612 bool erase_with( Q const& key, Less pred, Func f )
614 # ifdef CDS_CXX11_LAMBDA_SUPPORT
615 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
616 [&f](node_type& node) { cds::unref(f)( node.m_Value ); } );
618 erase_functor_wrapper<Func> fw( f );
619 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(), cds::ref(fw) );
623 /// Extracts the item with specified \p key
624 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
625 The function searches an item with key equal to \p key,
626 unlinks it from the set, and returns it in \p dest parameter.
627 If the item with key equal to \p key is not found the function returns \p false.
629 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
631 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
632 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
636 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
637 splitlist_set theSet;
640 splitlist_set::guarded_ptr gp;
641 theSet.extract( gp, 5 );
645 // Destructor of gp releases internal HP guard
649 template <typename Q>
650 bool extract( guarded_ptr& dest, Q const& key )
652 return extract_( dest.guard(), key );
655 /// Extracts the item using compare functor \p pred
657 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(guarded_ptr&, Q const&)"
658 but \p pred predicate is used for key comparing.
660 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
662 \p pred must imply the same element order as the comparator used for building the set.
664 template <typename Q, typename Less>
665 bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
667 return extract_with_( dest.guard(), key, pred );
670 /// Finds the key \p val
671 /** \anchor cds_nonintrusive_SplitListSet_find_func
673 The function searches the item with key equal to \p val and calls the functor \p f for item found.
674 The interface of \p Func functor is:
677 void operator()( value_type& item, Q& val );
680 where \p item is the item found, \p val is the <tt>find</tt> function argument.
682 You may pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
684 The functor may change non-key fields of \p item. Note that the functor is only guarantee
685 that \p item cannot be disposed during functor is executing.
686 The functor does not serialize simultaneous access to the set's \p item. If such access is
687 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
689 The \p val argument is non-const since it can be used as \p f functor destination i.e., the functor
690 may modify both arguments.
692 Note the hash functor specified for class \p Traits template parameter
693 should accept a parameter of type \p Q that can be not the same as \p value_type.
695 The function returns \p true if \p val is found, \p false otherwise.
697 template <typename Q, typename Func>
698 bool find( Q& val, Func f )
700 return find_( val, f );
703 /// Finds the key \p val using \p pred predicate for searching
705 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
706 but \p pred is used for key comparing.
707 \p Less functor has the interface like \p std::less.
708 \p Less must imply the same element order as the comparator used for building the set.
710 template <typename Q, typename Less, typename Func>
711 bool find_with( Q& val, Less pred, Func f )
713 return find_with_( val, pred, f );
716 /// Finds the key \p val
717 /** \anchor cds_nonintrusive_SplitListSet_find_cfunc
719 The function searches the item with key equal to \p val and calls the functor \p f for item found.
720 The interface of \p Func functor is:
723 void operator()( value_type& item, Q const& val );
726 where \p item is the item found, \p val is the <tt>find</tt> function argument.
728 You may pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
730 The functor may change non-key fields of \p item. Note that the functor is only guarantee
731 that \p item cannot be disposed during functor is executing.
732 The functor does not serialize simultaneous access to the set's \p item. If such access is
733 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
735 Note the hash functor specified for class \p Traits template parameter
736 should accept a parameter of type \p Q that can be not the same as \p value_type.
738 The function returns \p true if \p val is found, \p false otherwise.
740 template <typename Q, typename Func>
741 bool find( Q const& val, Func f )
743 return find_( val, f );
746 /// Finds the key \p val using \p pred predicate for searching
748 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_cfunc "find(Q const&, Func)"
749 but \p pred is used for key comparing.
750 \p Less functor has the interface like \p std::less.
751 \p Less must imply the same element order as the comparator used for building the set.
753 template <typename Q, typename Less, typename Func>
754 bool find_with( Q const& val, Less pred, Func f )
756 return find_with_( val, pred, f );
759 /// Finds the key \p val
760 /** \anchor cds_nonintrusive_SplitListSet_find_val
762 The function searches the item with key equal to \p val
763 and returns \p true if it is found, and \p false otherwise.
765 Note the hash functor specified for class \p Traits template parameter
766 should accept a parameter of type \p Q that can be not the same as \ref value_type.
768 template <typename Q>
769 bool find( Q const& val )
771 return base_class::find( val );
774 /// Finds the key \p val using \p pred predicate for searching
776 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
777 but \p pred is used for key comparing.
778 \p Less functor has the interface like \p std::less.
779 \p Less must imply the same element order as the comparator used for building the set.
781 template <typename Q, typename Less>
782 bool find_with( Q const& val, Less pred )
784 return base_class::find_with( val, typename maker::template predicate_wrapper<Less>::type() );
787 /// Finds the key \p key and return the item found
788 /** \anchor cds_nonintrusive_SplitListSet_hp_get
789 The function searches the item with key equal to \p key
790 and assigns the item found to guarded pointer \p ptr.
791 The function returns \p true if \p key is found, and \p false otherwise.
792 If \p key is not found the \p ptr parameter is not changed.
794 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
798 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
799 splitlist_set theSet;
802 splitlist_set::guarded_ptr gp;
803 if ( theSet.get( gp, 5 )) {
807 // Destructor of guarded_ptr releases internal HP guard
811 Note the compare functor specified for split-list set
812 should accept a parameter of type \p Q that can be not the same as \p value_type.
814 template <typename Q>
815 bool get( guarded_ptr& ptr, Q const& key )
817 return get_( ptr.guard(), key );
820 /// Finds \p key and return the item found
822 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( guarded_ptr&, Q const&)"
823 but \p pred is used for comparing the keys.
825 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
827 \p pred must imply the same element order as the comparator used for building the set.
829 template <typename Q, typename Less>
830 bool get_with( guarded_ptr& ptr, Q const& key, Less pred )
832 return get_with_( ptr.guard(), key, pred );
835 /// Clears the set (non-atomic)
837 The function unlink all items from the set.
838 The function is not atomic and not lock-free and should be used for debugging only.
845 /// Checks if the set is empty
847 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
848 Thus, the correct item counting feature is an important part of split-list set implementation.
852 return base_class::empty();
855 /// Returns item count in the set
858 return base_class::size();
863 using base_class::extract_;
864 using base_class::get_;
866 template <typename Q, typename Less>
867 bool extract_with_( typename gc::Guard& guard, Q const& key, Less pred )
869 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
872 template <typename Q, typename Less>
873 bool get_with_( typename gc::Guard& guard, Q const& key, Less pred )
875 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
883 }} // namespace cds::container
885 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_SET_H