3 #ifndef __CDS_CONTAINER_SKIP_LIST_MAP_NOGC_H
4 #define __CDS_CONTAINER_SKIP_LIST_MAP_NOGC_H
6 #include <cds/container/skip_list_set_nogc.h>
8 namespace cds { namespace container {
10 namespace skip_list { namespace details {
11 struct map_key_accessor
13 template <typename NodeType>
14 typename NodeType::stored_value_type::first_type const& operator()( NodeType const& node ) const
16 return node.m_Value.first;
19 }} // namespace skip_list::details
22 /// Lock-free skip-list map (template specialization for gc::nogc)
23 /** @ingroup cds_nonintrusive_map
24 \anchor cds_nonintrusive_SkipListMap_nogc
26 This specialization is intended for so-called persistent usage when no item
27 reclamation may be performed. The class does not support deleting of map item.
28 See \ref cds_nonintrusive_SkipListMap_hp "SkipListMap" for detailed description.
31 - \p K - type of a key to be stored in the map.
32 - \p T - type of a value to be stored in the map.
33 - \p Traits - map traits, default is \p skip_list::traits
34 It is possible to declare option-based list with \p cds::container::skip_list::make_traits
35 metafunction istead of \p Traits template argument.
40 #ifdef CDS_DOXYGEN_INVOKED
41 typename Traits = skip_list::traits
46 class SkipListMap< cds::gc::nogc, Key, T, Traits >:
47 #ifdef CDS_DOXYGEN_INVOKED
48 protected SkipListSet< cds::gc::nogc, std::pair< Key const, T >, Traits >
50 protected SkipListSet<
52 ,std::pair< Key const, T >
53 ,typename cds::opt::replace_key_accessor< Traits, skip_list::details::map_key_accessor >::type
60 ,std::pair< Key const, T >
61 ,typename cds::opt::replace_key_accessor< Traits, skip_list::details::map_key_accessor >::type
66 typedef cds::gc::nogc gc; ///< Garbage collector
67 typedef Key key_type; ///< Key type
68 typedef T mapped_type; ///< Mapped type
69 typedef std::pair< key_type const, mapped_type> value_type; ///< Key-value pair stored in the map
70 typedef Traits traits; ///< Options specified
72 typedef typename base_class::back_off back_off; ///< Back-off strategy
73 typedef typename base_class::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the skip-list nodes
74 typedef typename base_class::item_counter item_counter; ///< Item counting policy
75 typedef typename base_class::key_comparator key_comparator; ///< key compare functor
76 typedef typename base_class::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model option
77 typedef typename base_class::stat stat; ///< internal statistics type
78 typedef typename base_class::random_level_generator random_level_generator; ///< random level generator
82 typedef typename base_class::node_type node_type;
83 typedef typename base_class::node_allocator node_allocator;
87 /// Default constructor
92 /// Destructor clears the map
99 Remember, the iterator <tt>operator -> </tt> and <tt>operator *</tt> returns \ref value_type pointer and reference.
100 To access item key and value use <tt>it->first</tt> and <tt>it->second</tt> respectively.
102 typedef typename base_class::iterator iterator;
104 /// Const forward iterator
105 typedef typename base_class::const_iterator const_iterator;
107 /// Returns a forward iterator addressing the first element in a map
109 For empty set \code begin() == end() \endcode
113 return base_class::begin();
116 /// Returns an iterator that addresses the location succeeding the last element in a map
118 Do not use the value returned by <tt>end</tt> function to access any item.
119 The returned value can be used only to control reaching the end of the set.
120 For empty set \code begin() == end() \endcode
124 return base_class::end();
127 /// Returns a forward const iterator addressing the first element in a map
128 const_iterator begin() const
130 return base_class::begin();
132 /// Returns a forward const iterator addressing the first element in a map
133 const_iterator cbegin() const
135 return base_class::cbegin();
138 /// Returns an const iterator that addresses the location succeeding the last element in a map
139 const_iterator end() const
141 return base_class::end();
143 /// Returns an const iterator that addresses the location succeeding the last element in a map
144 const_iterator cend() const
146 return base_class::cend();
150 /// Inserts new node with key and default value
152 The function creates a node with \p key and default value, and then inserts the node created into the map.
155 - The \ref key_type should be constructible from value of type \p K.
156 In trivial case, \p K is equal to \ref key_type.
157 - The \ref mapped_type should be default-constructible.
159 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
161 template <typename K>
162 iterator insert( K const& key )
164 //TODO: pass arguments by reference (make_pair makes copy)
165 return base_class::insert( std::make_pair( key, mapped_type() ) );
170 The function creates a node with copy of \p val value
171 and then inserts the node created into the map.
174 - The \ref key_type should be constructible from \p key of type \p K.
175 - The \ref mapped_type should be constructible from \p val of type \p V.
177 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
179 template <typename K, typename V>
180 iterator insert( K const& key, V const& val )
182 //TODO: pass arguments by reference (make_pair makes copy)
183 return base_class::insert( std::make_pair( key, val ) );
186 /// Inserts new node and initialize it by a functor
188 This function inserts new node with key \p key and if inserting is successful then it calls
189 \p func functor with signature
192 void operator()( value_type& item );
196 The argument \p item of user-defined functor \p func is the reference
197 to the map's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
198 User-defined functor \p func should guarantee that during changing item's value no any other changes
199 could be made on this map's item by concurrent threads.
201 The key_type should be constructible from value of type \p K.
203 The function allows to split creating of new item into three part:
204 - create item from \p key;
205 - insert new item into the map;
206 - if inserting is successful, initialize the value of item by calling \p f functor
208 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
209 it is preferable that the initialization should be completed only if inserting is successful.
211 Returns an iterator pointed to inserted value, or \p end() if inserting is failed
213 template <typename K, typename Func>
214 iterator insert_with( K const& key, Func func )
216 iterator it = insert( key );
222 /// For key \p key inserts data of type \p mapped_type created in-place from \p args
224 \p key_type should be constructible from type \p K
226 Returns \p true if inserting successful, \p false otherwise.
228 template <typename K, typename... Args>
229 iterator emplace( K&& key, Args&&... args )
231 return base_class::emplace( std::forward<K>(key), std::move(mapped_type(std::forward<Args>(args)...)));
234 /// Ensures that the key \p key exists in the map
236 The operation inserts new item if the key \p key is not found in the map.
237 Otherwise, the function returns an iterator that points to item found.
239 Returns <tt> std::pair<iterator, bool> </tt> where \p first is an iterator pointing to
240 item found or inserted, \p second is true if new item has been added or \p false if the item
241 already is in the list.
243 template <typename K>
244 std::pair<iterator, bool> ensure( K const& key )
246 //TODO: pass arguments by reference (make_pair makes copy)
247 return base_class::ensure( std::make_pair( key, mapped_type() ));
250 /// Finds the key \p key
251 /** \anchor cds_nonintrusive_SkipListMap_nogc_find_val
253 The function searches the item with key equal to \p key
254 and returns an iterator pointed to item found if the key is found,
255 and \ref end() otherwise
257 template <typename K>
258 iterator find( K const& key )
260 return base_class::find( key );
263 /// Finds the key \p key with comparing functor \p cmp
265 The function is an analog of \ref cds_nonintrusive_SkipListMap_nogc_find_val "find(K const&)"
266 but \p pred is used for key comparing.
267 \p Less functor has the interface like \p std::less.
268 \p Less must imply the same element order as the comparator used for building the set.
270 template <typename K, typename Less>
271 iterator find_with( K const& key, Less pred ) const
273 return base_class::find_with( key, pred );
276 /// Gets minimum key from the map
278 If the map is empty the function returns \p nullptr
280 value_type * get_min() const
282 return base_class::get_min();
285 /// Gets maximum key from the map
287 The function returns \p nullptr if the map is empty
289 value_type * get_max() const
291 return base_class::get_max();
294 /// Clears the map (not atomic)
296 Finding and/or inserting is prohibited while clearing.
297 Otherwise an unpredictable result may be encountered.
298 Thus, \p clear() may be used only for debugging purposes.
305 /// Checks if the map is empty
307 Emptiness is checked by item counting: if item count is zero then the map is empty.
308 Thus, the correct item counting feature is an important part of Michael's map implementation.
312 return base_class::empty();
315 /// Returns item count in the map
318 return base_class::size();
321 /// Returns maximum height of skip-list. The max height is a constant for each object and does not exceed 32.
322 static CDS_CONSTEXPR unsigned int max_height() CDS_NOEXCEPT
324 return base_class::max_height();
327 /// Returns const reference to internal statistics
328 stat const& statistics() const
330 return base_class::statistics();
334 }} // namespace cds::container
337 #endif // #ifndef __CDS_CONTAINER_SKIP_LIST_MAP_NOGC_H