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)...));
433 /// Ensures that the \p item exists in the set
435 The operation performs inserting or changing data with lock-free manner.
437 If the \p val key not found in the set, then the new item created from \p val
438 is inserted into the set. Otherwise, the functor \p func is called with the item found.
439 The functor \p Func should be a function with signature:
441 void func( bool bNew, value_type& item, const Q& val );
446 void operator()( bool bNew, value_type& item, const Q& val );
451 - \p bNew - \p true if the item has been inserted, \p false otherwise
452 - \p item - item of the set
453 - \p val - argument \p val passed into the \p ensure function
455 The functor may change non-key fields of the \p item.
457 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
458 \p second is true if new item has been added or \p false if the item with \p key
459 already is in the set.
461 @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
462 \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
465 template <typename Q, typename Func>
466 std::pair<bool, bool> ensure( Q const& val, Func func )
468 scoped_node_ptr pNode( alloc_node( val ));
470 std::pair<bool, bool> bRet = base_class::ensure( *pNode,
471 [&func, &val]( bool bNew, node_type& item, node_type const& /*val*/ ) {
472 func( bNew, item.m_Value, val );
475 if ( bRet.first && bRet.second )
480 /// Deletes \p key from the set
481 /** \anchor cds_nonintrusive_SplitListSet_erase_val
483 The item comparator should be able to compare the values of type \p value_type
486 Return \p true if key is found and deleted, \p false otherwise
488 template <typename Q>
489 bool erase( Q const& key )
491 return base_class::erase( key );
494 /// Deletes the item from the set using \p pred predicate for searching
496 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_val "erase(Q const&)"
497 but \p pred is used for key comparing.
498 \p Less functor has the interface like \p std::less.
499 \p Less must imply the same element order as the comparator used for building the set.
501 template <typename Q, typename Less>
502 bool erase_with( Q const& key, Less pred )
505 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type() );
508 /// Deletes \p key from the set
509 /** \anchor cds_nonintrusive_SplitListSet_erase_func
511 The function searches an item with key \p key, calls \p f functor
512 and deletes the item. If \p key is not found, the functor is not called.
514 The functor \p Func interface:
517 void operator()(value_type const& val);
521 Since the key of split-list \p value_type is not explicitly specified,
522 template parameter \p Q defines the key type searching in the list.
523 The list item comparator should be able to compare the values of the type \p value_type
526 Return \p true if key is found and deleted, \p false otherwise
528 template <typename Q, typename Func>
529 bool erase( Q const& key, Func f )
531 return base_class::erase( key, [&f](node_type& node) { f( node.m_Value ); } );
534 /// Deletes the item from the set using \p pred predicate for searching
536 The function is an analog of \ref cds_nonintrusive_SplitListSet_erase_func "erase(Q const&, Func)"
537 but \p pred is used for key comparing.
538 \p Less functor has the interface like \p std::less.
539 \p Less must imply the same element order as the comparator used for building the set.
541 template <typename Q, typename Less, typename Func>
542 bool erase_with( Q const& key, Less pred, Func f )
545 return base_class::erase_with( key, typename maker::template predicate_wrapper<Less>::type(),
546 [&f](node_type& node) { f( node.m_Value ); } );
549 /// Extracts the item with specified \p key
550 /** \anchor cds_nonintrusive_SplitListSet_hp_extract
551 The function searches an item with key equal to \p key,
552 unlinks it from the set, and returns it as \p guarded_ptr.
553 If \p key is not found the function returns an empty guarded pointer.
555 Note the compare functor should accept a parameter of type \p Q that may be not the same as \p value_type.
557 The extracted item is freed automatically when returned \p guarded_ptr object will be destroyed or released.
558 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
562 typedef cds::container::SplitListSet< your_template_args > splitlist_set;
563 splitlist_set theSet;
566 splitlist_set::guarded_ptr gp(theSet.extract( 5 ));
571 // Destructor of gp releases internal HP guard
575 template <typename Q>
576 guarded_ptr extract( Q const& key )
579 extract_( gp.guard(), key );
583 /// Extracts the item using compare functor \p pred
585 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_extract "extract(Q const&)"
586 but \p pred predicate is used for key comparing.
588 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
590 \p pred must imply the same element order as the comparator used for building the set.
592 template <typename Q, typename Less>
593 guarded_ptr extract_with( Q const& key, Less pred )
596 extract_with_( gp.guard(), key, pred );
600 /// Finds the key \p key
601 /** \anchor cds_nonintrusive_SplitListSet_find_func
603 The function searches the item with key equal to \p key and calls the functor \p f for item found.
604 The interface of \p Func functor is:
607 void operator()( value_type& item, Q& key );
610 where \p item is the item found, \p key is the <tt>find</tt> function argument.
612 The functor may change non-key fields of \p item. Note that the functor is only guarantee
613 that \p item cannot be disposed during functor is executing.
614 The functor does not serialize simultaneous access to the set's \p item. If such access is
615 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
617 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
618 may modify both arguments.
620 Note the hash functor specified for class \p Traits template parameter
621 should accept a parameter of type \p Q that can be not the same as \p value_type.
623 The function returns \p true if \p key is found, \p false otherwise.
625 template <typename Q, typename Func>
626 bool find( Q& key, Func f )
628 return find_( key, f );
631 template <typename Q, typename Func>
632 bool find( Q const& key, Func f )
634 return find_( key, f );
638 /// Finds the key \p key using \p pred predicate for searching
640 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_func "find(Q&, Func)"
641 but \p pred is used for key comparing.
642 \p Less functor has the interface like \p std::less.
643 \p Less must imply the same element order as the comparator used for building the set.
645 template <typename Q, typename Less, typename Func>
646 bool find_with( Q& key, Less pred, Func f )
648 return find_with_( key, pred, f );
651 template <typename Q, typename Less, typename Func>
652 bool find_with( Q const& key, Less pred, Func f )
654 return find_with_( key, pred, f );
658 /// Finds the key \p key
659 /** \anchor cds_nonintrusive_SplitListSet_find_val
661 The function searches the item with key equal to \p key
662 and returns \p true if it is found, and \p false otherwise.
664 Note the hash functor specified for class \p Traits template parameter
665 should accept a parameter of type \p Q that can be not the same as \ref value_type.
667 template <typename Q>
668 bool find( Q const& key )
670 return base_class::find( key );
673 /// Finds the key \p key using \p pred predicate for searching
675 The function is an analog of \ref cds_nonintrusive_SplitListSet_find_val "find(Q const&)"
676 but \p pred is used for key comparing.
677 \p Less functor has the interface like \p std::less.
678 \p Less must imply the same element order as the comparator used for building the set.
680 template <typename Q, typename Less>
681 bool find_with( Q const& key, Less pred )
684 return base_class::find_with( key, typename maker::template predicate_wrapper<Less>::type() );
687 /// Finds the key \p key and return the item found
688 /** \anchor cds_nonintrusive_SplitListSet_hp_get
689 The function searches the item with key equal to \p key
690 and returns the item found as \p guarded_ptr.
691 If \p key is not found the function returns an empty guarded pointer.
693 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
697 typedef cds::container::SplitListSet< your_template_params > splitlist_set;
698 splitlist_set theSet;
701 splitlist_set::guarded_ptr gp(theSet.get( 5 ));
706 // Destructor of guarded_ptr releases internal HP guard
710 Note the compare functor specified for split-list set
711 should accept a parameter of type \p Q that can be not the same as \p value_type.
713 template <typename Q>
714 guarded_ptr get( Q const& key )
717 get_( gp.guard(), key );
721 /// Finds \p key and return the item found
723 The function is an analog of \ref cds_nonintrusive_SplitListSet_hp_get "get( Q const&)"
724 but \p pred is used for comparing the keys.
726 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
728 \p pred must imply the same element order as the comparator used for building the set.
730 template <typename Q, typename Less>
731 guarded_ptr get_with( Q const& key, Less pred )
734 get_with_( gp.guard(), key, pred );
738 /// Clears the set (not atomic)
744 /// Checks if the set is empty
746 Emptiness is checked by item counting: if item count is zero then assume that the set is empty.
747 Thus, the correct item counting feature is an important part of split-list set implementation.
751 return base_class::empty();
754 /// Returns item count in the set
757 return base_class::size();
760 /// Returns internal statistics
761 stat const& statistics() const
763 return base_class::statistics();
768 using base_class::extract_;
769 using base_class::get_;
771 template <typename Q, typename Less>
772 bool extract_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
775 return base_class::extract_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
778 template <typename Q, typename Less>
779 bool get_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less pred )
782 return base_class::get_with_( guard, key, typename maker::template predicate_wrapper<Less>::type() );
790 }} // namespace cds::container
792 #endif // #ifndef CDSLIB_CONTAINER_SPLIT_LIST_SET_H