3 #ifndef __CDS_CONTAINER_SPLIT_LIST_MAP_H
4 #define __CDS_CONTAINER_SPLIT_LIST_MAP_H
6 #include <cds/container/split_list_set.h>
7 #include <cds/details/binary_functor_wrapper.h>
9 namespace cds { namespace container {
11 /// Split-ordered list map
12 /** @ingroup cds_nonintrusive_map
13 \anchor cds_nonintrusive_SplitListMap_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 intrusive::SplitListSet for a brief description of the split-list algorithm.
22 - \p GC - Garbage collector used
23 - \p Key - key type of an item stored in the map. It should be copy-constructible
24 - \p Value - value type stored in the map
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_map_rcu.h</tt>,
30 see \ref cds_nonintrusive_SplitListMap_rcu "SplitListMap<RCU>".
31 - for \ref cds::gc::nogc declared in <tt>cds/container/split_list_map_nogc.h</tt>,
32 see \ref cds_nonintrusive_SplitListMap_nogc "SplitListMap<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 map based on gc::HP GC
38 and MichaelList as ordered list implementation. Your map should map \p int key to <tt>std::string</tt> value.
39 So, you beginning your program with following include:
41 #include <cds/container/michael_list_hp.h>
42 #include <cds/container/split_list_map.h>
44 namespace cc = cds::container;
46 The inclusion order is important: first, include file for ordered-list implementation (for this example, <tt>cds/container/michael_list_hp.h</tt>),
47 then the header for split-list map <tt>cds/container/split_list_map.h</tt>.
49 Now, you should declare traits for split-list map. The main parts of traits are a hash functor for the map key and a comparing functor for ordered list.
50 We use <tt>std::hash<int></tt> as hash functor and <tt>std::less<int></tt> predicate as comparing functor.
52 The second attention: instead of using \p %MichaelList in \p %SplitListMap traits we use a tag <tt>cds::contaner::michael_list_tag</tt> for the Michael's list.
53 The split-list requires significant support from underlying ordered list class and it is not good idea to dive you
54 into deep implementation details of split-list and ordered list interrelations. The tag paradigm simplifies split-list interface.
57 // SplitListMap traits
58 struct foo_set_traits: public cc::split_list::type_traits
60 typedef cc::michael_list_tag ordered_list ; // what type of ordered list we want to use
61 typedef std::hash<int> hash ; // hash functor for the key stored in split-list map
63 // Type traits for our MichaelList class
64 struct ordered_list_traits: public cc::michael_list::type_traits
66 typedef std::less<int> less ; // use our std::less predicate as comparator to order list nodes
71 Now you are ready to declare our map class based on SplitListMap:
73 typedef cc::SplitListMap< cds::gc::PTB, int, std::string, foo_set_traits > int_string_map;
76 You may use the modern option-based declaration instead of classic type-traits-based one:
78 typedef cc:SplitListMap<
79 cs::gc::PTB // GC used
81 ,std::string // value type
82 ,cc::split_list::make_traits< // metafunction to build split-list traits
83 cc::split_list::ordered_list<cc::michael_list_tag> // tag for underlying ordered list implementation
84 ,cc::opt::hash< std::hash<int> > // hash functor
85 ,cc::split_list::ordered_list_traits< // ordered list traits desired
86 cc::michael_list::make_traits< // metafunction to build lazy list traits
87 cc::opt::less< std::less<int> > // less-based compare functor
93 In case of option-based declaration using split_list::make_traits metafunction the struct \p foo_set_traits is not required.
95 Now, the map of type \p int_string_map is ready to use in your program.
97 Note that in this example we show only mandatory type_traits parts, optional ones is the default and they are inherited
98 from cds::container::split_list::type_traits.
99 The <b>cds</b> library contains many other options for deep tuning of behavior of the split-list and
100 ordered-list containers.
106 #ifdef CDS_DOXYGEN_INVOKED
107 class Traits = split_list::type_traits
113 protected container::SplitListSet<
115 std::pair<Key const, Value>,
116 split_list::details::wrap_map_traits<Key, Value, Traits>
120 typedef container::SplitListSet<
122 std::pair<Key const, Value>,
123 split_list::details::wrap_map_traits<Key, Value, Traits>
128 typedef typename base_class::gc gc ; ///< Garbage collector
129 typedef Key key_type ; ///< key type
130 typedef Value mapped_type ; ///< type of value stored in the map
131 typedef Traits options ; ///< \p Traits template argument
133 typedef std::pair<key_type const, mapped_type> value_type ; ///< key-value pair type
134 typedef typename base_class::ordered_list ordered_list; ///< Underlying ordered list class
135 typedef typename base_class::key_comparator key_comparator ; ///< key compare functor
137 typedef typename base_class::hash hash ; ///< Hash functor for \ref key_type
138 typedef typename base_class::item_counter item_counter ; ///< Item counter type
142 typedef typename base_class::maker::type_traits::key_accessor key_accessor;
143 typedef typename base_class::node_type node_type;
147 typedef cds::gc::guarded_ptr< gc, node_type, value_type, details::guarded_ptr_cast_set<node_type, value_type> > guarded_ptr;
150 # ifndef CDS_CXX11_LAMBDA_SUPPORT
151 template <typename Func>
152 class ensure_functor_wrapper: protected cds::details::functor_wrapper<Func>
154 typedef cds::details::functor_wrapper<Func> base_class;
156 ensure_functor_wrapper() {}
157 ensure_functor_wrapper( Func f ): base_class(f) {}
159 template <typename Q>
160 void operator()( bool bNew, value_type& item, const Q& /*val*/ )
162 base_class::get()( bNew, item );
166 template <typename Func>
167 class find_functor_wrapper: protected cds::details::functor_wrapper<Func>
169 typedef cds::details::functor_wrapper<Func> base_class;
171 find_functor_wrapper() {}
172 find_functor_wrapper( Func f ): base_class(f) {}
174 template <typename Q>
175 void operator()( value_type& pair, Q const& /*val*/ )
177 base_class::get()( pair );
180 # endif // ifndef CDS_CXX11_LAMBDA_SUPPORT
184 /// Forward iterator (see SplitListSet::iterator)
186 Remember, the iterator <tt>operator -> </tt> and <tt>operator *</tt> returns \ref value_type pointer and reference.
187 To access item key and value use <tt>it->first</tt> and <tt>it->second</tt> respectively.
189 typedef typename base_class::iterator iterator;
191 /// Const forward iterator (see SplitListSet::const_iterator)
192 typedef typename base_class::const_iterator const_iterator;
194 /// Returns a forward iterator addressing the first element in a map
196 For empty map \code begin() == end() \endcode
200 return base_class::begin();
203 /// Returns an iterator that addresses the location succeeding the last element in a map
205 Do not use the value returned by <tt>end</tt> function to access any item.
206 The returned value can be used only to control reaching the end of the map.
207 For empty map \code begin() == end() \endcode
211 return base_class::end();
214 /// Returns a forward const iterator addressing the first element in a map
216 const_iterator begin() const
218 return base_class::begin();
220 const_iterator cbegin()
222 return base_class::cbegin();
226 /// Returns an const iterator that addresses the location succeeding the last element in a map
228 const_iterator end() const
230 return base_class::end();
232 const_iterator cend()
234 return base_class::cend();
239 /// Initializes split-ordered map of default capacity
241 The default capacity is defined in bucket table constructor.
242 See intrusive::split_list::expandable_bucket_table, intrusive::split_list::static_bucket_table
243 which selects by intrusive::split_list::dynamic_bucket_table option.
249 /// Initializes split-ordered map
251 size_t nItemCount ///< estimate average item count
252 , size_t nLoadFactor = 1 ///< load factor - average item count per bucket. Small integer up to 10, default is 1.
254 : base_class( nItemCount, nLoadFactor )
258 /// Inserts new node with key and default value
260 The function creates a node with \p key and default value, and then inserts the node created into the map.
263 - The \ref key_type should be constructible from value of type \p K.
264 In trivial case, \p K is equal to \ref key_type.
265 - The \ref mapped_type should be default-constructible.
267 Returns \p true if inserting successful, \p false otherwise.
269 template <typename K>
270 bool insert( K const& key )
272 //TODO: pass arguments by reference (make_pair makes copy)
273 return base_class::insert( std::make_pair( key, mapped_type() ) );
278 The function creates a node with copy of \p val value
279 and then inserts the node created into the map.
282 - The \ref key_type should be constructible from \p key of type \p K.
283 - The \ref mapped_type should be constructible from \p val of type \p V.
285 Returns \p true if \p val is inserted into the map, \p false otherwise.
287 template <typename K, typename V>
288 bool insert( K const& key, V const& val )
290 //TODO: pass arguments by reference (make_pair makes copy)
291 return base_class::insert( std::make_pair(key, val) );
294 /// Inserts new node and initialize it by a functor
296 This function inserts new node with key \p key and if inserting is successful then it calls
297 \p func functor with signature
300 void operator()( value_type& item );
304 The argument \p item of user-defined functor \p func is the reference
305 to the map's item inserted:
306 - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
307 - <tt>item.second</tt> is a reference to item's value that may be changed.
309 It should be keep in mind that concurrent modifications of \p <tt>item.second</tt> may be possible.
310 User-defined functor \p func should guarantee that during changing item's value no any other changes
311 could be made on this \p item by concurrent threads.
313 The user-defined functor can be passed by reference using <tt>boost::ref</tt>
314 and it is called only if inserting is successful.
316 The key_type should be constructible from value of type \p K.
318 The function allows to split creating of new item into two part:
319 - create item from \p key;
320 - insert new item into the map;
321 - if inserting is successful, initialize the value of item by calling \p func functor
323 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
324 it is preferable that the initialization should be completed only if inserting is successful.
326 template <typename K, typename Func>
327 bool insert_key( K const& key, Func func )
329 //TODO: pass arguments by reference (make_pair makes copy)
330 return base_class::insert( std::make_pair( key, mapped_type() ), func );
333 /// For key \p key inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
335 \p key_type should be constructible from type \p K
337 Returns \p true if inserting successful, \p false otherwise.
339 template <typename K, typename... Args>
340 bool emplace( K&& key, Args&&... args )
342 return base_class::emplace( std::forward<K>(key), std::move(mapped_type(std::forward<Args>(args)...)));
345 /// Ensures that the \p key exists in the map
347 The operation performs inserting or changing data with lock-free manner.
349 If the \p key not found in the map, then the new item created from \p key
350 is inserted into the map (note that in this case the \ref key_type should be
351 constructible from type \p K).
352 Otherwise, the functor \p func is called with item found.
353 The functor \p Func may be a function with signature:
355 void func( bool bNew, value_type& item );
360 void operator()( bool bNew, value_type& item );
365 - \p bNew - \p true if the item has been inserted, \p false otherwise
366 - \p item - item of the list
368 The functor may change any fields of the \p item.second that is \ref mapped_type;
369 however, \p func must guarantee that during changing no any other modifications
370 could be made on this item by concurrent threads.
372 You may pass \p func argument by reference using <tt>boost::ref</tt>.
374 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
375 \p second is true if new item has been added or \p false if the item with \p key
376 already is in the list.
378 template <typename K, typename Func>
379 std::pair<bool, bool> ensure( K const& key, Func func )
381 //TODO: pass arguments by reference (make_pair makes copy)
382 # ifdef CDS_CXX11_LAMBDA_SUPPORT
383 return base_class::ensure( std::make_pair( key, mapped_type() ),
384 [&func](bool bNew, value_type& item, value_type const& /*val*/) {
385 cds::unref(func)( bNew, item );
388 ensure_functor_wrapper<Func> fw( func );
389 return base_class::ensure( std::make_pair( key, mapped_type() ), cds::ref(fw) );
393 /// Deletes \p key from the map
394 /** \anchor cds_nonintrusive_SplitListMap_erase_val
396 Return \p true if \p key is found and deleted, \p false otherwise
398 template <typename K>
399 bool erase( K const& key )
401 return base_class::erase( key );
404 /// Deletes the item from the map using \p pred predicate for searching
406 The function is an analog of \ref cds_nonintrusive_SplitListMap_erase_val "erase(K const&)"
407 but \p pred is used for key comparing.
408 \p Less functor has the interface like \p std::less.
409 \p Less must imply the same element order as the comparator used for building the map.
411 template <typename K, typename Less>
412 bool erase_with( K const& key, Less pred )
414 return base_class::erase_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
417 /// Deletes \p key from the map
418 /** \anchor cds_nonintrusive_SplitListMap_erase_func
420 The function searches an item with key \p key, calls \p f functor
421 and deletes the item. If \p key is not found, the functor is not called.
423 The functor \p Func interface is:
426 void operator()(value_type& item) { ... }
429 The functor may be passed by reference using <tt>boost:ref</tt>
431 Return \p true if key is found and deleted, \p false otherwise
433 template <typename K, typename Func>
434 bool erase( K const& key, Func f )
436 return base_class::erase( key, f );
439 /// Deletes the item from the map using \p pred predicate for searching
441 The function is an analog of \ref cds_nonintrusive_SplitListMap_erase_func "erase(K const&, Func)"
442 but \p pred is used for key comparing.
443 \p Less functor has the interface like \p std::less.
444 \p Less must imply the same element order as the comparator used for building the map.
446 template <typename K, typename Less, typename Func>
447 bool erase_with( K const& key, Less pred, Func f )
449 return base_class::erase_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>(), f );
452 /// Extracts the item with specified \p key
453 /** \anchor cds_nonintrusive_SplitListMap_hp_extract
454 The function searches an item with key equal to \p key,
455 unlinks it from the map, and returns it in \p dest parameter.
456 If the item with key equal to \p key is not found the function returns \p false.
458 Note the compare functor should accept a parameter of type \p K that may be not the same as \p value_type.
460 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
461 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
465 typedef cds::container::SplitListMap< your_template_args > splitlist_map;
466 splitlist_map theMap;
469 splitlist_map::guarded_ptr gp;
470 theMap.extract( gp, 5 );
474 // Destructor of gp releases internal HP guard
478 template <typename K>
479 bool extract( guarded_ptr& dest, K const& key )
481 return base_class::extract_( dest.guard(), key );
484 /// Extracts the item using compare functor \p pred
486 The function is an analog of \ref cds_nonintrusive_SplitListMap_hp_extract "extract(guarded_ptr&, K const&)"
487 but \p pred predicate is used for key comparing.
489 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p K
491 \p pred must imply the same element order as the comparator used for building the map.
493 template <typename K, typename Less>
494 bool extract_with( guarded_ptr& dest, K const& key, Less pred )
496 return base_class::extract_with_( dest.guard(), key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
499 /// Finds the key \p key
500 /** \anchor cds_nonintrusive_SplitListMap_find_cfunc
502 The function searches the item with key equal to \p key and calls the functor \p f for item found.
503 The interface of \p Func functor is:
506 void operator()( value_type& item );
509 where \p item is the item found.
511 You may pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
513 The functor may change \p item.second. Note that the functor is only guarantee
514 that \p item cannot be disposed during functor is executing.
515 The functor does not serialize simultaneous access to the map's \p item. If such access is
516 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
518 The function returns \p true if \p key is found, \p false otherwise.
520 template <typename K, typename Func>
521 bool find( K const& key, Func f )
523 # ifdef CDS_CXX11_LAMBDA_SUPPORT
524 return base_class::find( key, [&f](value_type& pair, K const&){ cds::unref(f)( pair ); } );
526 find_functor_wrapper<Func> fw(f);
527 return base_class::find( key, cds::ref(fw) );
531 /// Finds the key \p val using \p pred predicate for searching
533 The function is an analog of \ref cds_nonintrusive_SplitListMap_find_cfunc "find(K const&, Func)"
534 but \p pred is used for key comparing.
535 \p Less functor has the interface like \p std::less.
536 \p Less must imply the same element order as the comparator used for building the map.
538 template <typename K, typename Less, typename Func>
539 bool find_with( K const& key, Less pred, Func f )
541 # ifdef CDS_CXX11_LAMBDA_SUPPORT
542 return base_class::find_with( key,
543 cds::details::predicate_wrapper<value_type, Less, key_accessor>(),
544 [&f](value_type& pair, K const&){ cds::unref(f)( pair ); } );
546 find_functor_wrapper<Func> fw(f);
547 return base_class::find_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>(), cds::ref(fw) );
551 /// Finds the key \p key
552 /** \anchor cds_nonintrusive_SplitListMap_find_val
554 The function searches the item with key equal to \p key
555 and returns \p true if it is found, and \p false otherwise.
557 template <typename K>
558 bool find( K const& key )
560 return base_class::find( key );
563 /// Finds the key \p val using \p pred predicate for searching
565 The function is an analog of \ref cds_nonintrusive_SplitListMap_find_val "find(K const&)"
566 but \p pred is used for key comparing.
567 \p Less functor has the interface like \p std::less.
568 \p Less must imply the same element order as the comparator used for building the map.
570 template <typename K, typename Less>
571 bool find_with( K const& key, Less pred )
573 return base_class::find( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
576 /// Finds \p key and return the item found
577 /** \anchor cds_nonintrusive_SplitListMap_hp_get
578 The function searches the item with key equal to \p key
579 and assigns the item found to guarded pointer \p ptr.
580 The function returns \p true if \p key is found, and \p false otherwise.
581 If \p key is not found the \p ptr parameter is not changed.
583 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
587 typedef cds::container::SplitListMap< your_template_params > splitlist_map;
588 splitlist_map theMap;
591 splitlist_map::guarded_ptr gp;
592 if ( theMap.get( gp, 5 )) {
596 // Destructor of guarded_ptr releases internal HP guard
600 Note the compare functor specified for split-list map
601 should accept a parameter of type \p K that can be not the same as \p value_type.
603 template <typename K>
604 bool get( guarded_ptr& ptr, K const& key )
606 return base_class::get_( ptr.guard(), key );
609 /// Finds \p key and return the item found
611 The function is an analog of \ref cds_nonintrusive_SplitListMap_hp_get "get( guarded_ptr&, K const&)"
612 but \p pred is used for comparing the keys.
614 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p K
616 \p pred must imply the same element order as the comparator used for building the map.
618 template <typename K, typename Less>
619 bool get_with( guarded_ptr& ptr, K const& key, Less pred )
621 return base_class::get_with_( ptr.guard(), key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
624 /// Clears the map (non-atomic)
626 The function unlink all items from the map.
627 The function is not atomic and not lock-free and should be used for debugging only.
634 /// Checks if the map is empty
636 Emptiness is checked by item counting: if item count is zero then the map is empty.
637 Thus, the correct item counting is an important part of the map implementation.
641 return base_class::empty();
644 /// Returns item count in the map
647 return base_class::size();
652 }} // namespace cds::container
654 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_MAP_H