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 # ifdef CDS_EMPLACE_SUPPORT
334 /// For key \p key inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
336 \p key_type should be constructible from type \p K
338 Returns \p true if inserting successful, \p false otherwise.
340 This function is available only for compiler that supports
341 variadic template and move semantics
343 template <typename K, typename... Args>
344 bool emplace( K&& key, Args&&... args )
346 return base_class::emplace( std::forward<K>(key), std::move(mapped_type(std::forward<Args>(args)...)));
351 /// Ensures that the \p key exists in the map
353 The operation performs inserting or changing data with lock-free manner.
355 If the \p key not found in the map, then the new item created from \p key
356 is inserted into the map (note that in this case the \ref key_type should be
357 constructible from type \p K).
358 Otherwise, the functor \p func is called with item found.
359 The functor \p Func may be a function with signature:
361 void func( bool bNew, value_type& item );
366 void operator()( bool bNew, value_type& item );
371 - \p bNew - \p true if the item has been inserted, \p false otherwise
372 - \p item - item of the list
374 The functor may change any fields of the \p item.second that is \ref mapped_type;
375 however, \p func must guarantee that during changing no any other modifications
376 could be made on this item by concurrent threads.
378 You may pass \p func argument by reference using <tt>boost::ref</tt>.
380 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
381 \p second is true if new item has been added or \p false if the item with \p key
382 already is in the list.
384 template <typename K, typename Func>
385 std::pair<bool, bool> ensure( K const& key, Func func )
387 //TODO: pass arguments by reference (make_pair makes copy)
388 # ifdef CDS_CXX11_LAMBDA_SUPPORT
389 return base_class::ensure( std::make_pair( key, mapped_type() ),
390 [&func](bool bNew, value_type& item, value_type const& /*val*/) {
391 cds::unref(func)( bNew, item );
394 ensure_functor_wrapper<Func> fw( func );
395 return base_class::ensure( std::make_pair( key, mapped_type() ), cds::ref(fw) );
399 /// Deletes \p key from the map
400 /** \anchor cds_nonintrusive_SplitListMap_erase_val
402 Return \p true if \p key is found and deleted, \p false otherwise
404 template <typename K>
405 bool erase( K const& key )
407 return base_class::erase( key );
410 /// Deletes the item from the map using \p pred predicate for searching
412 The function is an analog of \ref cds_nonintrusive_SplitListMap_erase_val "erase(K const&)"
413 but \p pred is used for key comparing.
414 \p Less functor has the interface like \p std::less.
415 \p Less must imply the same element order as the comparator used for building the map.
417 template <typename K, typename Less>
418 bool erase_with( K const& key, Less pred )
420 return base_class::erase_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
423 /// Deletes \p key from the map
424 /** \anchor cds_nonintrusive_SplitListMap_erase_func
426 The function searches an item with key \p key, calls \p f functor
427 and deletes the item. If \p key is not found, the functor is not called.
429 The functor \p Func interface is:
432 void operator()(value_type& item) { ... }
435 The functor may be passed by reference using <tt>boost:ref</tt>
437 Return \p true if key is found and deleted, \p false otherwise
439 template <typename K, typename Func>
440 bool erase( K const& key, Func f )
442 return base_class::erase( key, f );
445 /// Deletes the item from the map using \p pred predicate for searching
447 The function is an analog of \ref cds_nonintrusive_SplitListMap_erase_func "erase(K const&, Func)"
448 but \p pred is used for key comparing.
449 \p Less functor has the interface like \p std::less.
450 \p Less must imply the same element order as the comparator used for building the map.
452 template <typename K, typename Less, typename Func>
453 bool erase_with( K const& key, Less pred, Func f )
455 return base_class::erase_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>(), f );
458 /// Extracts the item with specified \p key
459 /** \anchor cds_nonintrusive_SplitListMap_hp_extract
460 The function searches an item with key equal to \p key,
461 unlinks it from the map, and returns it in \p dest parameter.
462 If the item with key equal to \p key is not found the function returns \p false.
464 Note the compare functor should accept a parameter of type \p K that may be not the same as \p value_type.
466 The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
467 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
471 typedef cds::container::SplitListMap< your_template_args > splitlist_map;
472 splitlist_map theMap;
475 splitlist_map::guarded_ptr gp;
476 theMap.extract( gp, 5 );
480 // Destructor of gp releases internal HP guard
484 template <typename K>
485 bool extract( guarded_ptr& dest, K const& key )
487 return base_class::extract_( dest.guard(), key );
490 /// Extracts the item using compare functor \p pred
492 The function is an analog of \ref cds_nonintrusive_SplitListMap_hp_extract "extract(guarded_ptr&, K const&)"
493 but \p pred predicate is used for key comparing.
495 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p K
497 \p pred must imply the same element order as the comparator used for building the map.
499 template <typename K, typename Less>
500 bool extract_with( guarded_ptr& dest, K const& key, Less pred )
502 return base_class::extract_with_( dest.guard(), key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
505 /// Finds the key \p key
506 /** \anchor cds_nonintrusive_SplitListMap_find_cfunc
508 The function searches the item with key equal to \p key and calls the functor \p f for item found.
509 The interface of \p Func functor is:
512 void operator()( value_type& item );
515 where \p item is the item found.
517 You may pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
519 The functor may change \p item.second. Note that the functor is only guarantee
520 that \p item cannot be disposed during functor is executing.
521 The functor does not serialize simultaneous access to the map's \p item. If such access is
522 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
524 The function returns \p true if \p key is found, \p false otherwise.
526 template <typename K, typename Func>
527 bool find( K const& key, Func f )
529 # ifdef CDS_CXX11_LAMBDA_SUPPORT
530 return base_class::find( key, [&f](value_type& pair, K const&){ cds::unref(f)( pair ); } );
532 find_functor_wrapper<Func> fw(f);
533 return base_class::find( key, cds::ref(fw) );
537 /// Finds the key \p val using \p pred predicate for searching
539 The function is an analog of \ref cds_nonintrusive_SplitListMap_find_cfunc "find(K const&, Func)"
540 but \p pred is used for key comparing.
541 \p Less functor has the interface like \p std::less.
542 \p Less must imply the same element order as the comparator used for building the map.
544 template <typename K, typename Less, typename Func>
545 bool find_with( K const& key, Less pred, Func f )
547 # ifdef CDS_CXX11_LAMBDA_SUPPORT
548 return base_class::find_with( key,
549 cds::details::predicate_wrapper<value_type, Less, key_accessor>(),
550 [&f](value_type& pair, K const&){ cds::unref(f)( pair ); } );
552 find_functor_wrapper<Func> fw(f);
553 return base_class::find_with( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>(), cds::ref(fw) );
557 /// Finds the key \p key
558 /** \anchor cds_nonintrusive_SplitListMap_find_val
560 The function searches the item with key equal to \p key
561 and returns \p true if it is found, and \p false otherwise.
563 template <typename K>
564 bool find( K const& key )
566 return base_class::find( key );
569 /// Finds the key \p val using \p pred predicate for searching
571 The function is an analog of \ref cds_nonintrusive_SplitListMap_find_val "find(K const&)"
572 but \p pred is used for key comparing.
573 \p Less functor has the interface like \p std::less.
574 \p Less must imply the same element order as the comparator used for building the map.
576 template <typename K, typename Less>
577 bool find_with( K const& key, Less pred )
579 return base_class::find( key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
582 /// Finds \p key and return the item found
583 /** \anchor cds_nonintrusive_SplitListMap_hp_get
584 The function searches the item with key equal to \p key
585 and assigns the item found to guarded pointer \p ptr.
586 The function returns \p true if \p key is found, and \p false otherwise.
587 If \p key is not found the \p ptr parameter is not changed.
589 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
593 typedef cds::container::SplitListMap< your_template_params > splitlist_map;
594 splitlist_map theMap;
597 splitlist_map::guarded_ptr gp;
598 if ( theMap.get( gp, 5 )) {
602 // Destructor of guarded_ptr releases internal HP guard
606 Note the compare functor specified for split-list map
607 should accept a parameter of type \p K that can be not the same as \p value_type.
609 template <typename K>
610 bool get( guarded_ptr& ptr, K const& key )
612 return base_class::get_( ptr.guard(), key );
615 /// Finds \p key and return the item found
617 The function is an analog of \ref cds_nonintrusive_SplitListMap_hp_get "get( guarded_ptr&, K const&)"
618 but \p pred is used for comparing the keys.
620 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p K
622 \p pred must imply the same element order as the comparator used for building the map.
624 template <typename K, typename Less>
625 bool get_with( guarded_ptr& ptr, K const& key, Less pred )
627 return base_class::get_with_( ptr.guard(), key, cds::details::predicate_wrapper<value_type, Less, key_accessor>() );
630 /// Clears the map (non-atomic)
632 The function unlink all items from the map.
633 The function is not atomic and not lock-free and should be used for debugging only.
640 /// Checks if the map is empty
642 Emptiness is checked by item counting: if item count is zero then the map is empty.
643 Thus, the correct item counting is an important part of the map implementation.
647 return base_class::empty();
650 /// Returns item count in the map
653 return base_class::size();
658 }} // namespace cds::container
660 #endif // #ifndef __CDS_CONTAINER_SPLIT_LIST_MAP_H