--- /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_IMPL_SKIP_LIST_SET_H
+#define CDSLIB_CONTAINER_IMPL_SKIP_LIST_SET_H
+
+#include <cds/details/binary_functor_wrapper.h>
+#include <cds/container/details/guarded_ptr_cast.h>
+
+namespace cds { namespace container {
+
+ /// Lock-free skip-list set
+ /** @ingroup cds_nonintrusive_set
+ \anchor cds_nonintrusive_SkipListSet_hp
+
+ 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 GC - Garbage collector used.
+ - \p T - type to be stored in the list.
+ - \p Traits - set traits, default is \p skip_list::traits.
+ It is possible to declare option-based list with \p cds::container::skip_list::make_traits metafunction
+ istead of \p Traits template argument.
+
+ @warning The skip-list requires up to 67 hazard pointers that may be critical for some GCs for which
+ the guard count is limited (like as \p gc::HP). Those GCs should be explicitly initialized with
+ hazard pointer enough: \code cds::gc::HP myhp( 67 ) \endcode. Otherwise an run-time exception may be raised
+ when you try to create skip-list object.
+
+ @note There are several specializations of \p %SkipListSet for each \p GC. You should include:
+ - <tt><cds/container/skip_list_set_hp.h></tt> for \p gc::HP garbage collector
+ - <tt><cds/container/skip_list_set_dhp.h></tt> for \p gc::DHP garbage collector
+ - <tt><cds/container/skip_list_set_rcu.h></tt> for \ref cds_nonintrusive_SkipListSet_rcu "RCU type"
+ - <tt><cds/container/skip_list_set_nogc.h></tt> for \ref cds_nonintrusive_SkipListSet_nogc "non-deletable SkipListSet"
+
+ <b>Iterators</b>
+
+ The class supports a forward iterator (\ref iterator and \ref const_iterator).
+ The iteration is ordered.
+ The iterator object is thread-safe: the element pointed by the iterator object is guarded,
+ so, the element cannot be reclaimed while the iterator object is alive.
+ However, passing an iterator object between threads is dangerous.
+
+ \warning Due to concurrent nature of skip-list set it is not guarantee that you can iterate
+ all elements in the set: any concurrent deletion can exclude the element
+ pointed by the iterator from the set, and your iteration can be terminated
+ before end of the set. Therefore, such iteration is more suitable for debugging purpose only
+
+ Remember, each iterator object requires 2 additional hazard pointers, that may be
+ a limited resource for \p GC like \p gc::HP (for \p gc::DHP the count of
+ guards is unlimited).
+
+ 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 \p end(), \p cend() member functions points to \p nullptr and should not be dereferenced.
+ */
+ template <
+ typename GC,
+ typename T,
+#ifdef CDS_DOXYGEN_INVOKED
+ typename Traits = skip_list::traits
+#else
+ typename Traits
+#endif
+ >
+ class SkipListSet:
+#ifdef CDS_DOXYGEN_INVOKED
+ protected intrusive::SkipListSet< GC, T, Traits >
+#else
+ protected details::make_skip_list_set< GC, T, Traits >::type
+#endif
+ {
+ //@cond
+ typedef details::make_skip_list_set< GC, T, Traits > maker;
+ typedef typename maker::type base_class;
+ //@endcond
+ public:
+ typedef GC gc; ///< Garbage collector used
+ typedef T value_type; ///< @anchor cds_containewr_SkipListSet_value_type Value type to be stored in the set
+ typedef Traits traits; ///< Options specified
+
+ typedef typename base_class::back_off back_off; ///< Back-off strategy
+ 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
+
+ static size_t const c_nHazardPtrCount = base_class::c_nHazardPtrCount; ///< Count of hazard pointer required for the skip-list
+
+ 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:
+ /// Guarded pointer
+ typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_set<node_type, value_type> > guarded_ptr;
+
+ protected:
+ //@cond
+ unsigned int random_level()
+ {
+ return base_class::random_level();
+ }
+ //@endcond
+
+ public:
+ /// Default ctor
+ SkipListSet()
+ : base_class()
+ {}
+
+ /// Destructor destroys the set object
+ ~SkipListSet()
+ {}
+
+ public:
+ ///@name Forward iterators (only for debugging purpose)
+ //@{
+ /// Iterator type
+ /**
+ The forward iterator has some features:
+ - it has no post-increment operator
+ - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
+ For some GC (like as \p gc::HP), a guard is a limited resource per thread, so an exception (or assertion) "no free guard"
+ may be thrown if the limit of guard count per thread is exceeded.
+ - The iterator cannot be moved across thread boundary because it contains thread-private GC's guard.
+ - Iterator ensures thread-safety even if you delete the item the iterator points to. However, in case of concurrent
+ deleting operations there is no guarantee that you iterate all item in the list.
+ Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
+
+ @warning Use this iterator on the concurrent container for debugging purpose only.
+
+ The iterator interface:
+ \code
+ class iterator {
+ public:
+ // Default constructor
+ iterator();
+
+ // Copy construtor
+ iterator( iterator const& src );
+
+ // Dereference operator
+ value_type * operator ->() const;
+
+ // Dereference operator
+ value_type& operator *() const;
+
+ // Preincrement operator
+ iterator& operator ++();
+
+ // Assignment operator
+ iterator& operator = (iterator const& src);
+
+ // Equality operators
+ bool operator ==(iterator const& i ) const;
+ bool operator !=(iterator const& i ) const;
+ };
+ \endcode
+ */
+ 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 set
+ iterator begin()
+ {
+ return iterator( base_class::begin());
+ }
+
+ /// Returns a forward const iterator addressing the first element in a set
+ const_iterator begin() const
+ {
+ return const_iterator( base_class::begin());
+ }
+
+ /// Returns a forward const iterator addressing the first element in a set
+ const_iterator cbegin() const
+ {
+ return const_iterator( base_class::cbegin());
+ }
+
+ /// Returns a forward iterator that addresses the location succeeding the last element in a set.
+ iterator end()
+ {
+ return iterator( base_class::end());
+ }
+
+ /// Returns a forward const iterator that addresses the location succeeding the last element in a set.
+ const_iterator end() const
+ {
+ return const_iterator( base_class::end());
+ }
+
+ /// Returns a forward const iterator that addresses the location succeeding the last element in a set.
+ const_iterator cend() const
+ {
+ return const_iterator( base_class::cend());
+ }
+ //@}
+
+ public:
+ /// Inserts new node
+ /**
+ The function creates a node with copy of \p val value
+ and then inserts the node created into the set.
+
+ The type \p Q should contain as minimum the complete key for the node.
+ The object of \ref value_type should be constructible from a value of type \p Q.
+ In trivial case, \p Q is equal to \ref value_type.
+
+ Returns \p true if \p val is inserted into the set, \p false otherwise.
+ */
+ template <typename Q>
+ bool insert( Q const& val )
+ {
+ scoped_node_ptr sp( node_allocator().New( random_level(), val ));
+ if ( base_class::insert( *sp.get())) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Inserts new node
+ /**
+ The function allows to split creating of new item into two part:
+ - create item with key only
+ - insert new item into the set
+ - if inserting is success, calls \p f functor to initialize value-fields of \p val.
+
+ The functor signature is:
+ \code
+ void func( value_type& val );
+ \endcode
+ where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
+ \p val no any other changes could be made on this set's item by concurrent threads.
+ The user-defined functor is called only if the inserting is success.
+ */
+ template <typename Q, typename Func>
+ bool insert( Q const& val, Func f )
+ {
+ scoped_node_ptr sp( node_allocator().New( random_level(), val ));
+ if ( base_class::insert( *sp.get(), [&f]( node_type& v ) { f( v.m_Value ); } )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Updates the item
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If the \p val key not found in the set, then the new item created from \p val
+ will be inserted into the set iff \p bInsert is \p true.
+ Otherwise, if \p val is found, the functor \p func will be called with the item found.
+
+ The functor \p Func signature:
+ \code
+ struct my_functor {
+ void operator()( bool bNew, value_type& item, const Q& val );
+ };
+ \endcode
+ where:
+ - \p bNew - \p true if the item has been inserted, \p false otherwise
+ - \p item - item of the set
+ - \p val - argument \p key passed into the \p %update() function
+
+ The functor may change non-key fields of the \p item; however, \p func must guarantee
+ that during changing no any other modifications could be made on this item by concurrent threads.
+
+ Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successful,
+ i.e. the item has been inserted or updated,
+ \p second is \p true if new item has been added or \p false if the item with key equal to \p val
+ already exists.
+
+ @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
+ */
+ template <typename Q, typename Func>
+ std::pair<bool, bool> update( const Q& val, Func func, bool bInsert = true )
+ {
+ scoped_node_ptr sp( node_allocator().New( random_level(), val ));
+ std::pair<bool, bool> bRes = base_class::update( *sp,
+ [&func, &val](bool bNew, node_type& node, node_type&){ func( bNew, node.m_Value, val ); },
+ bInsert );
+ if ( bRes.first && bRes.second )
+ sp.release();
+ return bRes;
+ }
+ //@cond
+ template <typename Q, typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( const Q& val, Func func )
+ {
+ return update( val, func, true );
+ }
+ //@endcond
+
+ /// Inserts data of type \p value_type created in-place from <tt>std::forward<Args>(args)...</tt>
+ /**
+ Returns \p true if inserting successful, \p false otherwise.
+ */
+ template <typename... Args>
+ bool emplace( Args&&... args )
+ {
+ scoped_node_ptr sp( node_allocator().New( random_level(), std::forward<Args>(args)... ));
+ if ( base_class::insert( *sp.get())) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Delete \p key from the set
+ /** \anchor cds_nonintrusive_SkipListSet_erase_val
+
+ The set item comparator should be able to compare the type \p value_type
+ and the type \p Q.
+
+ Return \p true if key is found and deleted, \p false otherwise
+ */
+ template <typename Q>
+ bool erase( Q const& key )
+ {
+ return base_class::erase( key );
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListSet_erase_val "erase(Q 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 set.
+ */
+ template <typename Q, typename Less>
+ bool erase_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return base_class::erase_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor >());
+ }
+
+ /// Delete \p key from the set
+ /** \anchor cds_nonintrusive_SkipListSet_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 const& val);
+ };
+ \endcode
+
+ Since the key of \p value_type is not explicitly specified,
+ template parameter \p Q defines the key type to search in the list.
+ The list item comparator should be able to compare the type \p T of list item
+ and the type \p Q.
+
+ Return \p true if key is found and deleted, \p false otherwise
+ */
+ template <typename Q, typename Func>
+ bool erase( Q const& key, Func f )
+ {
+ return base_class::erase( key, [&f]( node_type const& node) { f( node.m_Value ); } );
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListSet_erase_func "erase(Q 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 set.
+ */
+ template <typename Q, typename Less, typename Func>
+ bool erase_with( Q const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return base_class::erase_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor >(),
+ [&f]( node_type const& node) { f( node.m_Value ); } );
+ }
+
+ /// Extracts the item from the set with specified \p key
+ /** \anchor cds_nonintrusive_SkipListSet_hp_extract
+ The function searches an item with key equal to \p key in the set,
+ unlinks it from the set, and returns it as \p guarded_ptr.
+ If \p key is not found the function returns an empty guarded pointer.
+
+ Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
+
+ The item extracted is freed automatically by garbage collector \p GC
+ when returned \p guarded_ptr object will be destroyed or released.
+ @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::container::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
+ skip_list theList;
+ // ...
+ {
+ skip_list::guarded_ptr gp(theList.extract( 5 ))
+ if ( gp ) {
+ // Deal with gp
+ // ...
+ }
+ // Destructor of gp releases internal HP guard and frees the pointer
+ }
+ \endcode
+ */
+ template <typename Q>
+ guarded_ptr extract( Q const& key )
+ {
+ return base_class::extract_( key, typename base_class::key_comparator());
+ }
+
+ /// Extracts the item from the set with comparing functor \p pred
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListSet_hp_extract "extract(Q const&)"
+ but \p pred predicate is used for key comparing.
+
+ \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
+ in any order.
+ \p pred must imply the same element order as the comparator used for building the set.
+ */
+ template <typename Q, typename Less>
+ guarded_ptr extract_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ typedef cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor > wrapped_less;
+ return base_class::extract_( key, cds::opt::details::make_comparator_from_less<wrapped_less>());
+ }
+
+ /// Extracts an item with minimal key from the set
+ /**
+ The function searches an item with minimal key, unlinks it, and returns pointer to the item found as \p guarded_ptr.
+ If the skip-list is empty the function returns an empty guarded pointer.
+
+ The item extracted is freed automatically by garbage collector \p GC
+ when returned \p guarded_ptr object will be destroyed or released.
+ @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::continer::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
+ skip_list theList;
+ // ...
+ {
+ skip_list::guarded_ptr gp( theList.extract_min());
+ if ( gp ) {
+ // Deal with gp
+ //...
+ }
+ // Destructor of gp releases internal HP guard and then frees the pointer
+ }
+ \endcode
+ */
+ guarded_ptr extract_min()
+ {
+ return base_class::extract_min_();
+ }
+
+ /// Extracts an item with maximal key from the set
+ /**
+ The function searches an item with maximal key, unlinks it, and returns the pointer to item found as \p guarded_ptr.
+ If the skip-list is empty the function returns an empty guarded pointer.
+
+ The item found is freed by garbage collector \p GC automatically
+ when returned \p guarded_ptr object will be destroyed or released.
+ @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::container::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
+ skip_list theList;
+ // ...
+ {
+ skip_list::guarded_ptr gp( theList.extract_max());
+ if ( gp ) {
+ // Deal with gp
+ //...
+ }
+ // Destructor of gp releases internal HP guard and then frees the pointer
+ }
+ \endcode
+ */
+ guarded_ptr extract_max()
+ {
+ return base_class::extract_max_();
+ }
+
+ /// Find the \p key
+ /** \anchor cds_nonintrusive_SkipListSet_find_func
+
+ 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, Q& key );
+ };
+ \endcode
+ where \p item is the item found, \p key is the <tt>find</tt> function argument.
+
+ The functor may change non-key fields of \p item. Note that the functor is only guarantee
+ that \p item cannot be disposed during functor is executing.
+ The functor does not serialize simultaneous access to the set's \p item. If such access is
+ possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
+
+ Note the hash functor specified for class \p Traits template parameter
+ should accept a parameter of type \p Q that may be not the same as \p value_type.
+
+ The function returns \p true if \p key is found, \p false otherwise.
+ */
+ template <typename Q, typename Func>
+ bool find( Q& key, Func f )
+ {
+ return base_class::find( key, [&f]( node_type& node, Q& v ) { f( node.m_Value, v ); });
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
+ {
+ return base_class::find( key, [&f]( node_type& node, Q& v ) { f( node.m_Value, v ); } );
+ }
+ //@endcond
+
+ /// Finds \p key using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListSet_find_func "find(Q&, 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 set.
+ */
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return base_class::find_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor >(),
+ [&f]( node_type& node, Q& v ) { f( node.m_Value, v ); } );
+ }
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return base_class::find_with( key, cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor >(),
+ [&f]( node_type& node, Q const& v ) { f( node.m_Value, v ); } );
+ }
+ //@endcond
+
+ /// Checks whether the set 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.
+ */
+ template <typename Q>
+ bool contains( Q const& key )
+ {
+ return base_class::contains( key );
+ }
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
+
+ /// Checks whether the set 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 Q, typename Less>
+ bool contains( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return base_class::contains( key, cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor >());
+ }
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
+
+ /// Finds \p key and return the item found
+ /** \anchor cds_nonintrusive_SkipListSet_hp_get
+ The function searches the item with key equal to \p key
+ and returns a guarded pointer to the item found.
+ If \p key is not found the function returns an empty guarded pointer.
+
+ It is safe when a concurrent thread erases the item returned in \p result guarded pointer.
+ In this case the item will be freed later by garbage collector \p GC automatically
+ when \p guarded_ptr object will be destroyed or released.
+ @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::container::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
+ skip_list theList;
+ // ...
+ {
+ skip_list::guarded_ptr gp( theList.get( 5 ));
+ if ( theList.get( 5 )) {
+ // Deal with gp
+ //...
+ }
+ // Destructor of guarded_ptr releases internal HP guard
+ }
+ \endcode
+
+ Note the compare functor specified for class \p Traits template parameter
+ should accept a parameter of type \p Q that can be not the same as \p value_type.
+ */
+ template <typename Q>
+ guarded_ptr get( Q const& key )
+ {
+ return base_class::get_with_( key, typename base_class::key_comparator());
+ }
+
+ /// Finds \p key and return the item found
+ /**
+ The function is an analog of \ref cds_nonintrusive_SkipListSet_hp_get "get(Q 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 value_type and \p Q
+ in any order.
+ \p pred must imply the same element order as the comparator used for building the set.
+ */
+ template <typename Q, typename Less>
+ guarded_ptr get_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ typedef cds::details::predicate_wrapper< node_type, Less, typename maker::value_accessor > wrapped_less;
+ return base_class::get_with_( key, cds::opt::details::make_comparator_from_less< wrapped_less >());
+ }
+
+ /// Clears the set (not atomic).
+ /**
+ The function deletes all items from the set.
+ The function is not atomic, thus, in multi-threaded environment with parallel insertions
+ this sequence
+ \code
+ set.clear();
+ assert( set.empty());
+ \endcode
+ the assertion could be raised.
+
+ For each item the \ref disposer provided by \p Traits template parameter will be called.
+ */
+ void clear()
+ {
+ base_class::clear();
+ }
+
+ /// Checks if the set is empty
+ bool empty() const
+ {
+ return base_class::empty();
+ }
+
+ /// Returns item count in the set
+ /**
+ The value returned depends on item counter type provided by \p Traits template parameter.
+ If it is \p atomicity::empty_item_counter this function always returns 0.
+ Therefore, the function is not suitable for checking the set emptiness, use \p empty()
+ member function for this purpose.
+ */
+ 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_IMPL_SKIP_LIST_SET_H
projects / c11concurrency-benchmarks.git / blobdiff