3 #ifndef __CDS_CONTAINER_MICHAEL_MAP_NOGC_H
4 #define __CDS_CONTAINER_MICHAEL_MAP_NOGC_H
6 #include <cds/container/details/michael_map_base.h>
7 #include <cds/gc/nogc.h>
8 #include <cds/details/allocator.h>
10 namespace cds { namespace container {
12 /// Michael's hash map (template specialization for \p cds::gc::nogc)
13 /** @ingroup cds_nonintrusive_map
14 \anchor cds_nonintrusive_MichaelHashMap_nogc
16 This specialization is so-called append-only when no item
17 reclamation may be performed. The class does not support deleting of map item.
19 See \ref cds_nonintrusive_MichaelHashMap_hp "MichaelHashMap" for description of template parameters.
23 #ifdef CDS_DOXYGEN_INVOKED
24 class Traits = michael_map::traits
29 class MichaelHashMap<cds::gc::nogc, OrderedList, Traits>
32 typedef cds::gc::nogc gc; ///< No garbage collector
33 typedef OrderedList bucket_type; ///< type of ordered list used as a bucket implementation
34 typedef Traits traits; ///< Map traits
36 typedef typename bucket_type::key_type key_type; ///< key type
37 typedef typename bucket_type::mapped_type mapped_type; ///< type of value to be stored in the map
38 typedef typename bucket_type::value_type value_type; ///< Pair used as the some functor's argument
40 typedef typename bucket_type::key_comparator key_comparator; ///< key comparing functor
42 /// Hash functor for \ref key_type and all its derivatives that you use
43 typedef typename cds::opt::v::hash_selector< typename traits::hash >::type hash;
44 typedef typename traits::item_counter item_counter; ///< Item counter type
46 /// Bucket table allocator
47 typedef cds::details::Allocator< bucket_type, typename traits::allocator > bucket_table_allocator;
51 typedef typename bucket_type::iterator bucket_iterator;
52 typedef typename bucket_type::const_iterator bucket_const_iterator;
56 item_counter m_ItemCounter; ///< Item counter
57 hash m_HashFunctor; ///< Hash functor
58 bucket_type * m_Buckets; ///< bucket table
62 const size_t m_nHashBitmask;
67 /// Calculates hash value of \p key
68 size_t hash_value( key_type const & key ) const
70 return m_HashFunctor( key ) & m_nHashBitmask;
73 /// Returns the bucket (ordered list) for \p key
74 bucket_type& bucket( key_type const& key )
76 return m_Buckets[ hash_value( key ) ];
83 \p IsConst - constness boolean flag
85 The forward iterator for Michael's map is based on \p OrderedList forward iterator and has some features:
86 - it has no post-increment operator, only pre-increment
87 - it iterates items in unordered fashion
89 template <bool IsConst>
90 class iterator_type: private cds::intrusive::michael_set::details::iterator< bucket_type, IsConst >
93 typedef cds::intrusive::michael_set::details::iterator< bucket_type, IsConst > base_class;
94 friend class MichaelHashMap;
99 //typedef typename base_class::bucket_type bucket_type;
100 typedef typename base_class::bucket_ptr bucket_ptr;
101 typedef typename base_class::list_iterator list_iterator;
103 //typedef typename bucket_type::key_type key_type;
107 /// Value pointer type (const for const_iterator)
108 typedef typename cds::details::make_const_type<typename MichaelHashMap::mapped_type, IsConst>::pointer value_ptr;
109 /// Value reference type (const for const_iterator)
110 typedef typename cds::details::make_const_type<typename MichaelHashMap::mapped_type, IsConst>::reference value_ref;
112 /// Key-value pair pointer type (const for const_iterator)
113 typedef typename cds::details::make_const_type<typename MichaelHashMap::value_type, IsConst>::pointer pair_ptr;
114 /// Key-value pair reference type (const for const_iterator)
115 typedef typename cds::details::make_const_type<typename MichaelHashMap::value_type, IsConst>::reference pair_ref;
119 iterator_type( list_iterator const& it, bucket_ptr pFirst, bucket_ptr pLast )
120 : base_class( it, pFirst, pLast )
131 iterator_type( const iterator_type& src )
135 /// Dereference operator
136 pair_ptr operator ->() const
138 assert( base_class::m_pCurBucket != nullptr );
139 return base_class::m_itList.operator ->();
142 /// Dereference operator
143 pair_ref operator *() const
145 assert( base_class::m_pCurBucket != nullptr );
146 return base_class::m_itList.operator *();
150 iterator_type& operator ++()
152 base_class::operator++();
156 /// Assignment operator
157 iterator_type& operator = (const iterator_type& src)
159 base_class::operator =(src);
163 /// Returns current bucket (debug function)
164 bucket_ptr bucket() const
166 return base_class::bucket();
169 /// Equality operator
171 bool operator ==(iterator_type<C> const& i ) const
173 return base_class::operator ==( i );
175 /// Equality operator
177 bool operator !=(iterator_type<C> const& i ) const
179 return !( *this == i );
182 /// Checks if the iterator is not equal to \p end()
183 explicit operator bool() const
185 return *this != iterator_type();
192 typedef iterator_type< false > iterator;
194 /// Const forward iterator
195 typedef iterator_type< true > const_iterator;
197 /// Returns a forward iterator addressing the first element in a set
199 For empty set \code begin() == end() \endcode
203 return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() );
206 /// Returns an iterator that addresses the location succeeding the last element in a set
208 Do not use the value returned by <tt>end</tt> function to access any item.
209 The returned value can be used only to control reaching the end of the set.
210 For empty set \code begin() == end() \endcode
214 return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
217 /// Returns a forward const iterator addressing the first element in a set
219 const_iterator begin() const
221 return get_const_begin();
223 const_iterator cbegin()
225 return get_const_begin();
229 /// Returns an const iterator that addresses the location succeeding the last element in a set
231 const_iterator end() const
233 return get_const_end();
235 const_iterator cend()
237 return get_const_end();
243 const_iterator get_const_begin() const
245 return const_iterator( const_cast<bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count() );
247 const_iterator get_const_end() const
249 return const_iterator( const_cast<bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
254 /// Initialize the map
255 /** @copydetails cds_nonintrusive_MichaelHashMap_hp_ctor
258 size_t nMaxItemCount, ///< estimation of max item count in the hash set
259 size_t nLoadFactor ///< load factor: estimation of max number of items in the bucket
260 ) : m_nHashBitmask( michael_map::details::init_hash_bitmask( nMaxItemCount, nLoadFactor ))
262 // GC and OrderedList::gc must be the same
263 static_assert( std::is_same<gc, typename bucket_type::gc>::value, "GC and OrderedList::gc must be the same");
265 // atomicity::empty_item_counter is not allowed as a item counter
266 static_assert( !std::is_same<item_counter, atomicity::empty_item_counter>::value,
267 "cds::atomicity::empty_item_counter is not allowed as a item counter");
269 m_Buckets = bucket_table_allocator().NewArray( bucket_count() );
272 /// Clears hash set and destroys it
276 bucket_table_allocator().Delete( m_Buckets, bucket_count() );
279 /// Inserts new node with key and default value
281 The function creates a node with \p key and default value, and then inserts the node created into the map.
284 - The \ref key_type should be constructible from value of type \p K.
285 In trivial case, \p K is equal to \ref key_type.
286 - The \ref mapped_type should be default-constructible.
288 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
290 template <typename K>
291 iterator insert( const K& key )
293 bucket_type& refBucket = bucket( key );
294 bucket_iterator it = refBucket.insert( key );
296 if ( it != refBucket.end() ) {
298 return iterator( it, &refBucket, m_Buckets + bucket_count() );
306 The function creates a node with copy of \p val value
307 and then inserts the node created into the map.
310 - The \ref key_type should be constructible from \p key of type \p K.
311 - The \ref mapped_type should be constructible from \p val of type \p V.
313 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
315 template <typename K, typename V>
316 iterator insert( K const& key, V const& val )
318 bucket_type& refBucket = bucket( key );
319 bucket_iterator it = refBucket.insert( key, val );
321 if ( it != refBucket.end() ) {
323 return iterator( it, &refBucket, m_Buckets + bucket_count() );
329 /// Inserts new node and initialize it by a functor
331 This function inserts new node with key \p key and if inserting is successful then it calls
332 \p func functor with signature
335 void operator()( value_type& item );
339 The argument \p item of user-defined functor \p func is the reference
340 to the map's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
342 The user-defined functor it is called only if the inserting is successful.
343 The \p key_type should be constructible from value of type \p K.
345 The function allows to split creating of new item into two part:
346 - create item from \p key;
347 - insert new item into the map;
348 - if inserting is successful, initialize the value of item by calling \p f functor
350 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
351 it is preferable that the initialization should be completed only if inserting is successful.
353 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
355 @warning For \ref cds_nonintrusive_MichaelKVList_nogc "MichaelKVList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
356 \ref cds_nonintrusive_LazyKVList_nogc "LazyKVList" provides exclusive access to inserted item and does not require any node-level
359 template <typename K, typename Func>
360 iterator insert_key( const K& key, Func func )
362 bucket_type& refBucket = bucket( key );
363 bucket_iterator it = refBucket.insert_key( key, func );
365 if ( it != refBucket.end() ) {
367 return iterator( it, &refBucket, m_Buckets + bucket_count() );
373 /// For key \p key inserts data of type \p mapped_type created from \p args
375 \p key_type should be constructible from type \p K
377 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
379 template <typename K, typename... Args>
380 iterator emplace( K&& key, Args&&... args )
382 bucket_type& refBucket = bucket( key );
383 bucket_iterator it = refBucket.emplace( std::forward<K>(key), std::forward<Args>(args)... );
385 if ( it != refBucket.end() ) {
387 return iterator( it, &refBucket, m_Buckets + bucket_count() );
393 /// Ensures that the key \p key exists in the map
395 The operation inserts new item if the key \p key is not found in the map.
396 Otherwise, the function returns an iterator that points to item found.
398 Returns <tt> std::pair<iterator, bool> </tt> where \p first is an iterator pointing to
399 item found or inserted, \p second is true if new item has been added or \p false if the item
400 already is in the list.
402 @warning For \ref cds_nonintrusive_MichaelKVList_nogc "MichaelKVList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
403 \ref cds_nonintrusive_LazyKVList_nogc "LazyKVList" provides exclusive access to inserted item and does not require any node-level
406 template <typename K>
407 std::pair<iterator, bool> ensure( const K& key )
409 bucket_type& refBucket = bucket( key );
410 std::pair<bucket_iterator, bool> ret = refBucket.ensure( key );
415 return std::make_pair( iterator( ret.first, &refBucket, m_Buckets + bucket_count() ), ret.second );
418 /// Find the key \p key
419 /** \anchor cds_nonintrusive_MichaelMap_nogc_find
421 The function searches the item with key equal to \p key
422 and returns an iterator pointed to item found if the key is found,
423 and \ref end() otherwise
425 template <typename K>
426 iterator find( const K& key )
428 bucket_type& refBucket = bucket( key );
429 bucket_iterator it = refBucket.find( key );
431 if ( it != refBucket.end() )
432 return iterator( it, &refBucket, m_Buckets + bucket_count() );
437 /// Finds the key \p val using \p pred predicate for searching
439 The function is an analog of \ref cds_nonintrusive_MichaelMap_nogc_find "find(K const&)"
440 but \p pred is used for key comparing.
441 \p Less functor has the interface like \p std::less.
442 \p Less must imply the same element order as the comparator used for building the map.
444 template <typename K, typename Less>
445 iterator find_with( const K& key, Less pred )
447 bucket_type& refBucket = bucket( key );
448 bucket_iterator it = refBucket.find_with( key, pred );
450 if ( it != refBucket.end() )
451 return iterator( it, &refBucket, m_Buckets + bucket_count() );
456 /// Clears the map (not atomic)
459 for ( size_t i = 0; i < bucket_count(); ++i )
460 m_Buckets[i].clear();
461 m_ItemCounter.reset();
464 /// Checks whether the map is empty
466 Emptiness is checked by item counting: if item count is zero then the map is empty.
467 Thus, the correct item counting feature is an important part of Michael's map implementation.
474 /// Returns item count in the map
477 return m_ItemCounter;
480 /// Returns the size of hash table
482 Since \p %MichaelHashMap cannot dynamically extend the hash table size,
483 the value returned is an constant depending on object initialization parameters;
484 see \p MichaelHashMap::MichaelHashMap for explanation.
486 size_t bucket_count() const
488 return m_nHashBitmask + 1;
491 }} // namespace cds::container
493 #endif // ifndef __CDS_CONTAINER_MICHAEL_MAP_NOGC_H