--- /dev/null
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef CDSLIB_CONTAINER_SKIP_LIST_MAP_RCU_H
+#define CDSLIB_CONTAINER_SKIP_LIST_MAP_RCU_H
+
+#include <cds/container/details/skip_list_base.h>
+#include <cds/intrusive/skip_list_rcu.h>
+#include <cds/container/details/make_skip_list_map.h>
+
+namespace cds { namespace container {
+
+ /// Lock-free skip-list map (template specialization for \ref cds_urcu_desc "RCU")
+ /** @ingroup cds_nonintrusive_map
+ \anchor cds_nonintrusive_SkipListMap_rcu
+
+ The implementation of well-known probabilistic data structure called skip-list
+ invented by W.Pugh in his papers:
+ - [1989] W.Pugh Skip Lists: A Probabilistic Alternative to Balanced Trees
+ - [1990] W.Pugh A Skip List Cookbook
+
+ A skip-list is a probabilistic data structure that provides expected logarithmic
+ time search without the need of rebalance. The skip-list is a collection of sorted
+ linked list. Nodes are ordered by key. Each node is linked into a subset of the lists.
+ Each list has a level, ranging from 0 to 32. The bottom-level list contains
+ all the nodes, and each higher-level list is a sublist of the lower-level lists.
+ Each node is created with a random top level (with a random height), and belongs
+ to all lists up to that level. The probability that a node has the height 1 is 1/2.
+ The probability that a node has the height N is 1/2 ** N (more precisely,
+ the distribution depends on an random generator provided, but our generators
+ have this property).
+
+ The lock-free variant of skip-list is implemented according to book
+ - [2008] M.Herlihy, N.Shavit "The Art of Multiprocessor Programming",
+ chapter 14.4 "A Lock-Free Concurrent Skiplist"
+
+ Template arguments:
+ - \p RCU - one of \ref cds_urcu_gc "RCU type".
+ - \p K - type of a key to be stored in the list.
+ - \p T - type of a value to be stored in the list.
+ - \p Traits - map traits, default is \p skip_list::traits.
+ It is possible to declare option-based list with \p cds::container::skip_list::make_traits metafunction
+ instead of \p Traits template argument.
+
+ Like STL map class, \p %SkipListMap stores its key-value pair as <tt>std:pair< K const, T></tt>.
+
+ @note Before including <tt><cds/container/skip_list_map_rcu.h></tt> you should include appropriate RCU header file,
+ see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
+
+ <b>Iterators</b>
+
+ The class supports a forward iterator (\ref iterator and \ref const_iterator).
+ The iteration is ordered.
+ You may iterate over skip-list set items only under RCU lock.
+ Only in this case the iterator is thread-safe since
+ while RCU is locked any set's item cannot be reclaimed.
+
+ The requirement of RCU lock during iterating means that deletion of the elements (i.e. \ref erase)
+ is not possible.
+
+ @warning The iterator object cannot be passed between threads
+
+ The iterator class supports the following minimalistic interface:
+ \code
+ struct iterator {
+ // Default ctor
+ iterator();
+
+ // Copy ctor
+ iterator( iterator const& s);
+
+ value_type * operator ->() const;
+ value_type& operator *() const;
+
+ // Pre-increment
+ iterator& operator ++();
+
+ // Copy assignment
+ iterator& operator = (const iterator& src);
+
+ bool operator ==(iterator const& i ) const;
+ bool operator !=(iterator const& i ) const;
+ };
+ \endcode
+ Note, the iterator object returned by \ref end, \p cend member functions points to \p nullptr and should not be dereferenced.
+
+ */
+ template <
+ typename RCU,
+ typename Key,
+ typename T,
+#ifdef CDS_DOXYGEN_INVOKED
+ typename Traits = skip_list::traits
+#else
+ typename Traits
+#endif
+ >
+ class SkipListMap< cds::urcu::gc< RCU >, Key, T, Traits >:
+#ifdef CDS_DOXYGEN_INVOKED
+ protected intrusive::SkipListSet< cds::urcu::gc< RCU >, std::pair<Key const, T>, Traits >
+#else
+ protected details::make_skip_list_map< cds::urcu::gc< RCU >, Key, T, Traits >::type
+#endif
+ {
+ //@cond
+ typedef details::make_skip_list_map< cds::urcu::gc< RCU >, Key, T, Traits > maker;
+ typedef typename maker::type base_class;
+ //@endcond
+ public:
+ typedef cds::urcu::gc< RCU > gc; ///< Garbage collector used
+ typedef Key key_type; ///< Key type
+ typedef T mapped_type; ///< Mapped type
+# ifdef CDS_DOXYGEN_INVOKED
+ typedef std::pair< K const, T> value_type; ///< Value type stored in the map
+# else
+ typedef typename maker::value_type value_type;
+# endif
+ typedef Traits traits; ///< Map traits
+
+ typedef typename base_class::back_off back_off; ///< Back-off strategy used
+ typedef typename traits::allocator allocator_type; ///< Allocator type used for allocate/deallocate the skip-list nodes
+ typedef typename base_class::item_counter item_counter; ///< Item counting policy used
+ typedef typename maker::key_comparator key_comparator; ///< key comparison functor
+ typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
+ typedef typename traits::random_level_generator random_level_generator; ///< random level generator
+ typedef typename traits::stat stat; ///< internal statistics type
+
+ protected:
+ //@cond
+ typedef typename maker::node_type node_type;
+ typedef typename maker::node_allocator node_allocator;
+
+ typedef std::unique_ptr< node_type, typename maker::node_deallocator > scoped_node_ptr;
+ //@endcond
+
+ public:
+ typedef typename base_class::rcu_lock rcu_lock; ///< RCU scoped lock
+ /// Group of \p extract_xxx functions do not require external locking
+ static constexpr const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal;
+
+ /// pointer to extracted node
+ using exempt_ptr = cds::urcu::exempt_ptr< gc, node_type, value_type, typename maker::intrusive_type_traits::disposer >;
+
+ private:
+ //@cond
+ struct raw_ptr_converter
+ {
+ value_type * operator()( node_type * p ) const
+ {
+ return p ? &p->m_Value : nullptr;
+ }
+
+ value_type& operator()( node_type& n ) const
+ {
+ return n.m_Value;
+ }
+
+ value_type const& operator()( node_type const& n ) const
+ {
+ return n.m_Value;
+ }
+ };
+ //@endcond
+
+ public:
+ /// Result of \p get(), \p get_with() functions - pointer to the node found
+ typedef cds::urcu::raw_ptr_adaptor< value_type, typename base_class::raw_ptr, raw_ptr_converter > raw_ptr;
+
+ protected:
+ //@cond
+ unsigned int random_level()
+ {
+ return base_class::random_level();
+ }
+ //@endcond
+
+ public:
+ /// Default ctor
+ SkipListMap()
+ : base_class()
+ {}
+
+ /// Destructor destroys the set object
+ ~SkipListMap()
+ {}
+
+ public:
+ ///@name Forward ordered iterators (thread-safe under RCU lock)
+ //@{
+ /// Forward iterator
+ /**
+ The forward iterator has some features:
+ - it has no post-increment operator
+ - it depends on iterator of underlying \p OrderedList
+
+ You may safely use iterators in multi-threaded environment only under RCU lock.
+ Otherwise, a crash is possible if another thread deletes the element the iterator points to.
+ */
+ typedef skip_list::details::iterator< typename base_class::iterator > iterator;
+
+ /// Const iterator type
+ typedef skip_list::details::iterator< typename base_class::const_iterator > const_iterator;
+
+ /// Returns a forward iterator addressing the first element in a map
+ iterator begin()
+ {
+ return iterator( base_class::begin());
+ }
+
+ /// Returns a forward const iterator addressing the first element in a map
+ const_iterator begin() const
+ {
+ return cbegin();
+ }
+ /// Returns a forward const iterator addressing the first element in a map
+ const_iterator cbegin() const
+ {
+ return const_iterator( base_class::cbegin());
+ }
+
+ /// Returns a forward iterator that addresses the location succeeding the last element in a map.
+ iterator end()
+ {
+ return iterator( base_class::end());
+ }
+
+ /// Returns a forward const iterator that addresses the location succeeding the last element in a map.
+ const_iterator end() const
+ {
+ return cend();
+ }
+ /// Returns a forward const iterator that addresses the location succeeding the last element in a map.
+ const_iterator cend() const
+ {
+ return const_iterator( base_class::cend());
+ }
+ //@}
+
+ public:
+ /// Inserts new node with key and default value
+ /**
+ The function creates a node with \p key and default value, and then inserts the node created into the map.
+
+ Preconditions:
+ - The \p key_type should be constructible from a value of type \p K.
+ In trivial case, \p K is equal to \p key_type.
+ - The \p mapped_type should be default-constructible.
+
+ RCU \p synchronize method can be called. RCU should not be locked.
+
+ Returns \p true if inserting successful, \p false otherwise.
+ */
+ template <typename K>
+ bool insert( K const& key )
+ {
+ return insert_with( key, [](value_type&){} );
+ }
+
+ /// Inserts new node
+ /**
+ The function creates a node with copy of \p val value
+ and then inserts the node created into the map.
+
+ Preconditions:
+ - The \p key_type should be constructible from \p key of type \p K.
+ - The \p value_type should be constructible from \p val of type \p V.
+
+ RCU \p synchronize method can be called. RCU should not be locked.
+
+ Returns \p true if \p val is inserted into the set, \p false otherwise.
+ */
+ template <typename K, typename V>
+ bool insert( K const& key, V const& val )
+ {
+ scoped_node_ptr pNode( node_allocator().New( random_level(), key, val ));
+ if ( base_class::insert( *pNode ))
+ {
+ pNode.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Inserts new node and initialize it by a functor
+ /**
+ This function inserts new node with key \p key and if inserting is successful then it calls
+ \p func functor with signature
+ \code
+ struct functor {
+ void operator()( value_type& item );
+ };
+ \endcode
+
+ The argument \p item of user-defined functor \p func is the reference
+ to the map's item inserted:
+ - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
+ - <tt>item.second</tt> is a reference to item's value that may be changed.
+
+ The function allows to split creating of new item into three part:
+ - create item from \p key;
+ - insert new item into the map;
+ - if inserting is successful, initialize the value of item by calling \p func functor
+
+ This can be useful if complete initialization of object of \p value_type is heavyweight and
+ it is preferable that the initialization should be completed only if inserting is successful.
+
+ RCU \p synchronize method can be called. RCU should not be locked.
+ */
+ template <typename K, typename Func>
+ bool insert_with( const K& key, Func func )
+ {
+ scoped_node_ptr pNode( node_allocator().New( random_level(), key ));
+ if ( base_class::insert( *pNode, [&func]( node_type& item ) { func( item.m_Value ); } )) {
+ pNode.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// For key \p key inserts data of type \p value_type created in-place from \p args
+ /**
+ Returns \p true if inserting successful, \p false otherwise.
+
+ RCU \p synchronize() method can be called. RCU should not be locked.
+ */
+ template <typename K, typename... Args>
+ bool emplace( K&& key, Args&&... args )
+ {
+ scoped_node_ptr pNode( node_allocator().New( random_level(), std::forward<K>(key), std::forward<Args>(args)... ));
+ if ( base_class::insert( *pNode )) {
+ pNode.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Updates data by \p key
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If the \p key not found in the map, then the new item created from \p key
+ is inserted into the map iff \p bInsert is \p true.
+ Otherwise, if \p key found, the functor \p func is called with item found.
+ The functor \p Func interface is:
+ \code
+ struct my_functor {
+ void operator()( bool bNew, value_type& item );
+ };
+ \endcode
+ where:
+ - \p bNew - \p true if the item has been inserted, \p false otherwise
+ - \p item - item of the map
+
+ The functor may change any fields of \p item.second.
+
+ RCU \p synchronize() method can be called. RCU should not be locked.
+
+ Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successful,
+ \p second is \p true if new item has been added or \p false if the item with \p key
+ already exists.
+
+ @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
+ */
+ template <typename K, typename Func>
+ std::pair<bool, bool> update( K const& key, Func func, bool bInsert = true )
+ {
+ scoped_node_ptr pNode( node_allocator().New( random_level(), key ));
+ std::pair<bool, bool> res = base_class::update( *pNode,
+ [&func](bool bNew, node_type& item, node_type const& ){ func( bNew, item.m_Value );},
+ bInsert
+ );
+ if ( res.first && res.second )
+ pNode.release();
+ return res;
+ }
+ //@cond
+ template <typename K, typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( K const& key, Func func )
+ {
+ return update( key, func, true );
+ }
+ //@endcond
+
+ /// Delete \p key from the map
+ /**\anchor cds_nonintrusive_SkipListMap_rcu_erase_val
+
+ RCU \p synchronize method can be called. RCU should not be locked.
+
+ Return \p true if \p key is found and deleted, \p false otherwise
+ */
+ template <typename K>
+ bool erase( K const& key )
+ {
+ return base_class::erase(key);
+ }
+
+ /// Deletes the item from the map using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListMap_rcu_erase_val "erase(K const&)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p Less must imply the same element order as the comparator used for building the map.
+ */
+ template <typename K, typename Less>
+ bool erase_with( K const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return base_class::erase_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >());
+ }
+
+ /// Delete \p key from the map
+ /** \anchor cds_nonintrusive_SkipListMap_rcu_erase_func
+
+ The function searches an item with key \p key, calls \p f functor
+ and deletes the item. If \p key is not found, the functor is not called.
+
+ The functor \p Func interface:
+ \code
+ struct extractor {
+ void operator()(value_type& item) { ... }
+ };
+ \endcode
+
+ RCU \p synchronize method can be called. RCU should not be locked.
+
+ Return \p true if key is found and deleted, \p false otherwise
+ */
+ template <typename K, typename Func>
+ bool erase( K const& key, Func f )
+ {
+ return base_class::erase( key, [&f]( node_type& node) { f( node.m_Value ); } );
+ }
+
+ /// Deletes the item from the map using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListMap_rcu_erase_func "erase(K const&, Func)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p Less must imply the same element order as the comparator used for building the map.
+ */
+ template <typename K, typename Less, typename Func>
+ bool erase_with( K const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return base_class::erase_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >(),
+ [&f]( node_type& node) { f( node.m_Value ); } );
+ }
+
+ /// Extracts the item from the map with specified \p key
+ /** \anchor cds_nonintrusive_SkipListMap_rcu_extract
+ The function searches an item with key equal to \p key in the map,
+ unlinks it from the set, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
+ If the item is not found the function returns an empty \p exempt_ptr
+
+ Note the compare functor from \p Traits class' template argument
+ should accept a parameter of type \p K that can be not the same as \p key_type.
+
+ RCU \p synchronize() method can be called. RCU should NOT be locked.
+
+ The function does not free the item found.
+ The item will be implicitly freed when the returned object is destroyed or when
+ its \p release() member function is called.
+ */
+ template <typename K>
+ exempt_ptr extract( K const& key )
+ {
+ return exempt_ptr( base_class::do_extract( key ));
+ }
+
+ /// Extracts the item from the map with comparing functor \p pred
+ /**
+ The function is an analog of \p extract(K const&) but \p pred predicate is used for key comparing.
+ \p Less has the semantics like \p std::less.
+ \p pred must imply the same element order as the comparator used for building the map.
+ */
+ template <typename K, typename Less>
+ exempt_ptr extract_with( K const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return exempt_ptr( base_class::do_extract_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >()));
+ }
+
+ /// Extracts an item with minimal key from the map
+ /**
+ The function searches an item with minimal key, unlinks it,
+ and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item.
+ If the skip-list is empty the function returns an empty \p exempt_ptr.
+
+ RCU \p synchronize method can be called. RCU should NOT be locked.
+
+ The function does not free the item found.
+ The item will be implicitly freed when the returned object is destroyed or when
+ its \p release() member function is called.
+ */
+ exempt_ptr extract_min()
+ {
+ return exempt_ptr( base_class::do_extract_min());
+ }
+
+ /// Extracts an item with maximal key from the map
+ /**
+ The function searches an item with maximal key, unlinks it from the set,
+ and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item.
+ If the skip-list is empty the function returns an empty \p exempt_ptr.
+
+ RCU \p synchronize method can be called. RCU should NOT be locked.
+
+ The function does not free the item found.
+ The item will be implicitly freed when the returned object is destroyed or when
+ its \p release() member function is called.
+ */
+ exempt_ptr extract_max()
+ {
+ return exempt_ptr( base_class::do_extract_max());
+ }
+
+ /// Find the key \p key
+ /** \anchor cds_nonintrusive_SkipListMap_rcu_find_cfunc
+
+ The function searches the item with key equal to \p key and calls the functor \p f for item found.
+ The interface of \p Func functor is:
+ \code
+ struct functor {
+ void operator()( value_type& item );
+ };
+ \endcode
+ where \p item is the item found.
+
+ The functor may change \p item.second.
+
+ The function applies RCU lock internally.
+
+ The function returns \p true if \p key is found, \p false otherwise.
+ */
+ template <typename K, typename Func>
+ bool find( K const& key, Func f )
+ {
+ return base_class::find( key, [&f](node_type& item, K const& ) { f( item.m_Value );});
+ }
+
+ /// Finds the key \p val using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListMap_rcu_find_cfunc "find(K const&, Func)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p Less must imply the same element order as the comparator used for building the map.
+ */
+ template <typename K, typename Less, typename Func>
+ bool find_with( K const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return base_class::find_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >(),
+ [&f](node_type& item, K const& ) { f( item.m_Value );});
+ }
+
+ /// Checks whether the map contains \p key
+ /**
+ The function searches the item with key equal to \p key
+ and returns \p true if it is found, and \p false otherwise.
+
+ The function applies RCU lock internally.
+ */
+ template <typename K>
+ bool contains( K const& key )
+ {
+ return base_class::contains( key );
+ }
+ //@cond
+ template <typename K>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( K const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
+
+ /// Checks whether the map contains \p key using \p pred predicate for searching
+ /**
+ The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p Less must imply the same element order as the comparator used for building the set.
+ */
+ template <typename K, typename Less>
+ bool contains( K const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return base_class::contains( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >());
+ }
+ //@cond
+ template <typename K, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( K const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
+
+ /// Finds the key \p key and return the item found
+ /** \anchor cds_nonintrusive_SkipListMap_rcu_get
+ The function searches the item with key equal to \p key and returns a \p raw_ptr object pointing to an item found.
+ If \p key is not found it returns empty \p raw_ptr.
+
+ Note the compare functor in \p Traits class' template argument
+ should accept a parameter of type \p K that can be not the same as \p key_type.
+
+ RCU should be locked before call of this function.
+ Returned item is valid only while RCU is locked:
+ \code
+ typedef cds::container::SkipListMap< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > skip_list;
+ skip_list theList;
+ // ...
+ typename skip_list::raw_ptr pVal;
+ {
+ // Lock RCU
+ skip_list::rcu_lock lock;
+
+ pVal = theList.get( 5 );
+ if ( pVal ) {
+ // Deal with pVal
+ //...
+ }
+ }
+ // You can manually release pVal after RCU-locked section
+ pVal.release();
+ \endcode
+ */
+ template <typename K>
+ raw_ptr get( K const& key )
+ {
+ return raw_ptr( base_class::get( key ));
+ }
+
+ /// Finds the key \p key and return the item found
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListMap_rcu_get "get(K const&)"
+ but \p pred is used for comparing the keys.
+
+ \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
+ in any order.
+ \p pred must imply the same element order as the comparator used for building the map.
+ */
+ template <typename K, typename Less>
+ raw_ptr get_with( K const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return raw_ptr( base_class::get_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::key_accessor >()));
+ }
+
+ /// Clears the map (not atomic)
+ void clear()
+ {
+ base_class::clear();
+ }
+
+ /// Checks if the map is empty
+ /**
+ Emptiness is checked by item counting: if item count is zero then the map is empty.
+ */
+ bool empty() const
+ {
+ return base_class::empty();
+ }
+
+ /// Returns item count in the map
+ size_t size() const
+ {
+ return base_class::size();
+ }
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return base_class::statistics();
+ }
+ };
+}} // namespace cds::container
+
+#endif // #ifndef CDSLIB_CONTAINER_SKIP_LIST_MAP_RCU_H
projects / c11concurrency-benchmarks.git / blobdiff