--- /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_MICHAEL_SET_RCU_H
+#define CDSLIB_CONTAINER_MICHAEL_SET_RCU_H
+
+#include <cds/container/details/michael_set_base.h>
+#include <cds/details/allocator.h>
+
+namespace cds { namespace container {
+
+ /// Michael's hash set (template specialization for \ref cds_urcu_desc "RCU")
+ /** @ingroup cds_nonintrusive_set
+ \anchor cds_nonintrusive_MichaelHashSet_rcu
+
+ Source:
+ - [2002] Maged Michael "High performance dynamic lock-free hash tables and list-based sets"
+
+ Michael's hash table algorithm is based on lock-free ordered list and it is very simple.
+ The main structure is an array \p T of size \p M. Each element in \p T is basically a pointer
+ to a hash bucket, implemented as a singly linked list. The array of buckets cannot be dynamically expanded.
+ However, each bucket may contain unbounded number of items.
+
+ Template parameters are:
+ - \p RCU - one of \ref cds_urcu_gc "RCU type"
+ - \p OrderedList - ordered list implementation used as the bucket for hash set, for example,
+ \ref cds_nonintrusive_MichaelList_rcu "MichaelList".
+ The ordered list implementation specifies the type \p T stored in the hash-set,
+ the comparison functor for the type \p T and other features specific for
+ the ordered list.
+ - \p Traits - set traits, default is michael_set::traits.
+ Instead of defining \p Traits struct you may use option-based syntax with michael_set::make_traits metafunction.
+
+ About hash functor see \ref cds_nonintrusive_MichaelHashSet_hash_functor "MichaelSet hash functor".
+
+ <b>How to use</b>
+
+ Suppose, we have the following type \p Foo that we want to store in your \p %MichaelHashSet:
+ \code
+ struct Foo {
+ int nKey ; // key field
+ int nVal ; // value field
+ };
+ \endcode
+
+ To use \p %MichaelHashSet for \p Foo values, you should first choose suitable ordered list class
+ that will be used as a bucket for the set. We will cds::urcu::general_buffered<> RCU type and
+ MichaelList as a bucket type.
+ You should include RCU-related header file (<tt>cds/urcu/general_buffered.h</tt> in this example)
+ before including <tt>cds/container/michael_set_rcu.h</tt>.
+ Also, for ordered list we should develop a comparator for our \p Foo struct.
+ \code
+ #include <cds/urcu/general_buffered.h>
+ #include <cds/container/michael_list_rcu.h>
+ #include <cds/container/michael_set_rcu.h>
+
+ namespace cc = cds::container;
+
+ // Foo comparator
+ struct Foo_cmp {
+ int operator ()(Foo const& v1, Foo const& v2 ) const
+ {
+ if ( std::less( v1.nKey, v2.nKey ))
+ return -1;
+ return std::less(v2.nKey, v1.nKey) ? 1 : 0;
+ }
+ };
+
+ // Ordered list
+ typedef cc::MichaelList< cds::urcu::gc< cds::urcu::general_buffered<> >, Foo,
+ typename cc::michael_list::make_traits<
+ cc::opt::compare< Foo_cmp > // item comparator option
+ >::type
+ > bucket_list;
+
+ // Hash functor for Foo
+ struct foo_hash {
+ size_t operator ()( int i ) const
+ {
+ return std::hash( i );
+ }
+ size_t operator()( Foo const& i ) const
+ {
+ return std::hash( i.nKey );
+ }
+ };
+
+ // Declare the set
+ // Note that \p RCU template parameter of ordered list must be equal \p RCU for the set.
+ typedef cc::MichaelHashSet< cds::urcu::gc< cds::urcu::general_buffered<> >, bucket_list,
+ cc::michael_set::make_traits<
+ cc::opt::hash< foo_hash >
+ >::type
+ > foo_set;
+
+ foo_set fooSet;
+ \endcode
+ */
+ template <
+ class RCU,
+ class OrderedList,
+#ifdef CDS_DOXYGEN_INVOKED
+ class Traits = michael_set::traits
+#else
+ class Traits
+#endif
+ >
+ class MichaelHashSet< cds::urcu::gc< RCU >, OrderedList, Traits >
+ {
+ public:
+ typedef cds::urcu::gc< RCU > gc; ///< RCU used as garbage collector
+ typedef OrderedList ordered_list; ///< type of ordered list to be used as a bucket implementation
+ typedef Traits traits; ///< Set traits
+
+ typedef typename ordered_list::value_type value_type; ///< type of value to be stored in the list
+ typedef typename ordered_list::key_comparator key_comparator; ///< key comparing functor
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename ordered_list::stat stat; ///< Internal statistics
+ typedef typename ordered_list::exempt_ptr exempt_ptr; ///< pointer to extracted node
+ typedef typename ordered_list::raw_ptr raw_ptr; ///< Return type of \p get() member function and its derivatives
+#endif
+
+ /// Hash functor for \ref value_type and all its derivatives that you use
+ typedef typename cds::opt::v::hash_selector< typename traits::hash >::type hash;
+ typedef typename traits::item_counter item_counter; ///< Item counter type
+ typedef typename traits::allocator allocator; ///< Bucket table allocator
+
+ typedef typename ordered_list::rcu_lock rcu_lock; ///< RCU scoped lock
+ /// Group of \p extract_xxx functions require external locking if underlying ordered list requires that
+ static constexpr const bool c_bExtractLockExternal = ordered_list::c_bExtractLockExternal;
+
+ // GC and OrderedList::gc must be the same
+ static_assert(std::is_same<gc, typename ordered_list::gc>::value, "GC and OrderedList::gc must be the same");
+
+ //@cond
+ typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat;
+
+ typedef typename ordered_list::template rebind_traits<
+ cds::opt::item_counter< cds::atomicity::empty_item_counter >
+ , cds::opt::stat< typename bucket_stat::wrapped_stat >
+ >::type internal_bucket_type_;
+
+ class internal_bucket_type: public internal_bucket_type_
+ {
+ typedef internal_bucket_type_ base_class;
+ public:
+ using base_class::base_class;
+ using typename base_class::node_type;
+ using base_class::alloc_node;
+ using base_class::insert_node;
+ using base_class::node_to_value;
+ };
+
+ typedef typename internal_bucket_type::exempt_ptr exempt_ptr;
+ typedef typename internal_bucket_type::raw_ptr raw_ptr;
+ typedef typename bucket_stat::stat stat;
+ //@endcond
+
+ protected:
+ //@cond
+ /// Bucket table allocator
+ typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator;
+
+ const size_t m_nHashBitmask;
+ hash m_HashFunctor; ///< Hash functor
+ internal_bucket_type* m_Buckets; ///< bucket table
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
+ //@endcond
+
+ public:
+ ///@name Forward iterators (thread-safe under RCU lock)
+ //@{
+ /// Forward iterator
+ /**
+ The forward iterator for Michael's set is based on \p OrderedList forward iterator and has some features:
+ - it has no post-increment operator
+ - it iterates items in unordered fashion
+
+ 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.
+
+ 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 michael_set::details::iterator< internal_bucket_type, false > iterator;
+
+ /// Const forward iterator
+ typedef michael_set::details::iterator< internal_bucket_type, true > const_iterator;
+
+ /// Returns a forward iterator addressing the first element in a set
+ /**
+ For empty set \code begin() == end() \endcode
+ */
+ iterator begin()
+ {
+ return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count());
+ }
+
+ /// Returns an iterator that addresses the location succeeding the last element in a set
+ /**
+ Do not use the value returned by <tt>end</tt> function to access any item.
+ The returned value can be used only to control reaching the end of the set.
+ For empty set \code begin() == end() \endcode
+ */
+ iterator end()
+ {
+ return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
+ }
+
+ /// Returns a forward const iterator addressing the first element in a set
+ const_iterator begin() const
+ {
+ return get_const_begin();
+ }
+
+ /// Returns a forward const iterator addressing the first element in a set
+ const_iterator cbegin() const
+ {
+ return get_const_begin();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
+ const_iterator end() const
+ {
+ return get_const_end();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
+ const_iterator cend() const
+ {
+ return get_const_end();
+ }
+ //@}
+
+ public:
+ /// Initialize hash set
+ /**
+ The Michael's hash set is non-expandable container. You should point the average count of items \p nMaxItemCount
+ when you create an object.
+ \p nLoadFactor parameter defines average count of items per bucket and it should be small number between 1 and 10.
+ Remember, since the bucket implementation is an ordered list, searching in the bucket is linear [<tt>O(nLoadFactor)</tt>].
+
+ The ctor defines hash table size as rounding <tt>nMaxItemCount / nLoadFactor</tt> up to nearest power of two.
+ */
+ MichaelHashSet(
+ size_t nMaxItemCount, ///< estimation of max item count in the hash set
+ size_t nLoadFactor ///< load factor: estimation of max number of items in the bucket
+ ) : m_nHashBitmask( michael_set::details::init_hash_bitmask( nMaxItemCount, nLoadFactor ))
+ , m_Buckets( bucket_table_allocator().allocate( bucket_count()))
+ {
+ for ( auto it = m_Buckets, itEnd = m_Buckets + bucket_count(); it != itEnd; ++it )
+ construct_bucket<bucket_stat>( it );
+ }
+
+ /// Clears hash set and destroys it
+ ~MichaelHashSet()
+ {
+ clear();
+
+ for ( auto it = m_Buckets, itEnd = m_Buckets + bucket_count(); it != itEnd; ++it )
+ it->~internal_bucket_type();
+ bucket_table_allocator().deallocate( m_Buckets, bucket_count());
+
+ }
+
+ /// 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.
+
+ The function applies RCU lock internally.
+
+ Returns \p true if \p val is inserted into the set, \p false otherwise.
+ */
+ template <typename Q>
+ bool insert( Q&& val )
+ {
+ const bool bRet = bucket( val ).insert( std::forward<Q>( val ));
+ if ( bRet )
+ ++m_ItemCounter;
+ return bRet;
+ }
+
+ /// 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.
+ The user-defined functor is called only if the inserting is success.
+
+ The function applies RCU lock internally.
+
+ @warning For \ref cds_nonintrusive_MichaelList_rcu "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_nonintrusive_LazyList_rcu "LazyList" provides exclusive access to inserted item and does not require any node-level
+ synchronization.
+ */
+ template <typename Q, typename Func>
+ bool insert( Q&& val, Func f )
+ {
+ const bool bRet = bucket( val ).insert( std::forward<Q>( val ), f );
+ if ( bRet )
+ ++m_ItemCounter;
+ return bRet;
+ }
+
+ /// Updates the element
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If the item \p val not found in the set, then \p val is inserted iff \p bAllowInsert is \p true.
+ Otherwise, the functor \p func is called with item found.
+ The functor signature is:
+ \code
+ struct functor {
+ void operator()( bool bNew, value_type& item, Q const& val );
+ };
+ \endcode
+ with arguments:
+ - \p bNew - \p true if the item has been inserted, \p false otherwise
+ - \p item - item of the set
+ - \p val - argument \p val passed into the \p %update() function
+
+ The functor may change non-key fields of the \p item.
+
+ The function applies RCU lock internally.
+
+ 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 is in the set.
+
+ @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
+ synchronization.
+ */
+ template <typename Q, typename Func>
+ std::pair<bool, bool> update( Q const& val, Func func, bool bAllowInsert = true )
+ {
+ std::pair<bool, bool> bRet = bucket( val ).update( val, func, bAllowInsert );
+ if ( bRet.second )
+ ++m_ItemCounter;
+ return bRet;
+ }//@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 from \p args
+ /**
+ Returns \p true if inserting successful, \p false otherwise.
+
+ The function applies RCU lock internally.
+ */
+ template <typename... Args>
+ bool emplace( Args&&... args )
+ {
+ typename internal_bucket_type::node_type * pNode = internal_bucket_type::alloc_node( std::forward<Args>( args )... );
+ bool bRet = bucket( internal_bucket_type::node_to_value( *pNode )).insert_node( pNode );
+ if ( bRet )
+ ++m_ItemCounter;
+ return bRet;
+ }
+
+ /// Deletes \p key from the set
+ /** \anchor cds_nonintrusive_MichealSet_rcu_erase_val
+
+ Since the key of MichaelHashSet's item type \p value_type is not explicitly specified,
+ template parameter \p Q defines the key type searching in the list.
+ The set item comparator should be able to compare the type \p value_type
+ and the type \p Q.
+
+ 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 Q>
+ bool erase( Q const& key )
+ {
+ const bool bRet = bucket( key ).erase( key );
+ if ( bRet )
+ --m_ItemCounter;
+ return bRet;
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_MichealSet_rcu_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 )
+ {
+ const bool bRet = bucket( key ).erase_with( key, pred );
+ if ( bRet )
+ --m_ItemCounter;
+ return bRet;
+ }
+
+ /// Deletes \p key from the set
+ /** \anchor cds_nonintrusive_MichealSet_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 const& val);
+ };
+ \endcode
+
+ Since the key of %MichaelHashSet's \p value_type is not explicitly specified,
+ template parameter \p Q defines the key type searching in the list.
+ The list item comparator should be able to compare the type \p T of list item
+ and the type \p Q.
+
+ 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 Q, typename Func>
+ bool erase( Q const& key, Func f )
+ {
+ const bool bRet = bucket( key ).erase( key, f );
+ if ( bRet )
+ --m_ItemCounter;
+ return bRet;
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_MichealSet_rcu_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 )
+ {
+ const bool bRet = bucket( key ).erase_with( key, pred, f );
+ if ( bRet )
+ --m_ItemCounter;
+ return bRet;
+ }
+
+ /// Extracts an item from the set
+ /** \anchor cds_nonintrusive_MichaelHashSet_rcu_extract
+ The function searches an item with key equal to \p key in the set,
+ unlinks it from the set, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
+ If the item with the key equal to \p key is not found the function return an empty \p exempt_ptr.
+
+ The function just excludes the item from the set and returns a pointer to item found.
+ Depends on \p ordered_list you should or should not lock RCU before calling of this function:
+ - for the set based on \ref cds_nonintrusive_MichaelList_rcu "MichaelList" RCU should not be locked
+ - for the set based on \ref cds_nonintrusive_LazyList_rcu "LazyList" RCU should be locked
+ See ordered list implementation for details.
+
+ \code
+ #include <cds/urcu/general_buffered.h>
+ #include <cds/container/michael_list_rcu.h>
+ #include <cds/container/michael_set_rcu.h>
+
+ typedef cds::urcu::gc< general_buffered<> > rcu;
+ typedef cds::container::MichaelList< rcu, Foo > rcu_michael_list;
+ typedef cds::container::MichaelHashSet< rcu, rcu_michael_list, foo_traits > rcu_michael_set;
+
+ rcu_michael_set theSet;
+ // ...
+
+ typename rcu_michael_set::exempt_ptr p;
+
+ // For MichaelList we should not lock RCU
+
+ // Note that you must not delete the item found inside the RCU lock
+ p = theSet.extract( 10 );
+ if ( p ) {
+ // do something with p
+ ...
+ }
+
+ // We may safely release p here
+ // release() passes the pointer to RCU reclamation cycle
+ p.release();
+ \endcode
+ */
+ template <typename Q>
+ exempt_ptr extract( Q const& key )
+ {
+ exempt_ptr p = bucket( key ).extract( key );
+ if ( p )
+ --m_ItemCounter;
+ return p;
+ }
+
+ /// Extracts an item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \p extract(Q const&) but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p pred must imply the same element order as the comparator used for building the set.
+ */
+ template <typename Q, typename Less>
+ exempt_ptr extract_with( Q const& key, Less pred )
+ {
+ exempt_ptr p = bucket( key ).extract_with( key, pred );
+ if ( p )
+ --m_ItemCounter;
+ return p;
+ }
+
+ /// Finds the key \p key
+ /** \anchor cds_nonintrusive_MichealSet_rcu_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.
+
+ The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
+ can modify both arguments.
+
+ 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 applies RCU lock internally.
+
+ 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 bucket( key ).find( key, f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
+ {
+ return bucket( key ).find( key, f );
+ }
+ //@endcond
+
+ /// Finds the key \p key using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_nonintrusive_MichealSet_rcu_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 )
+ {
+ return bucket( key ).find_with( key, pred, f );
+ }
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
+ {
+ return bucket( key ).find_with( key, pred, f );
+ }
+ //@endcond
+
+ /// Checks whether the set contains \p key
+ /**
+
+ The function searches the item with key equal to \p key
+ and returns \p true if the key is found, and \p false otherwise.
+
+ Note the hash 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>
+ bool contains( Q const& key )
+ {
+ return bucket( key ).contains( key );
+ }
+ //@cond
+ template <typename Q>
+ CDS_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 an analog of <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 )
+ {
+ return bucket( key ).contains( key, pred );
+ }
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
+
+ /// Finds the key \p key and return the item found
+ /** \anchor cds_nonintrusive_MichaelHashSet_rcu_get
+ The function searches the item with key equal to \p key and returns the pointer to item found.
+ If \p key is not found it returns \p nullptr.
+ Note the type of returned value depends on underlying \p ordered_list.
+ For details, see documentation of ordered list you use.
+
+ Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
+
+ RCU should be locked before call of this function.
+ Returned item is valid only while RCU is locked:
+ \code
+ typedef cds::container::MichaelHashSet< your_template_parameters > hash_set;
+ hash_set theSet;
+ typename hash_set::raw_ptr gp;
+ // ...
+ {
+ // Lock RCU
+ hash_set::rcu_lock lock;
+
+ gp = theSet.get( 5 );
+ if ( gp ) {
+ // Deal with pVal
+ //...
+ }
+ // Unlock RCU by rcu_lock destructor
+ // gp can be reclaimed at any time after RCU has been unlocked
+ }
+ \endcode
+ */
+ template <typename Q>
+ raw_ptr get( Q const& key )
+ {
+ return bucket( key ).get( key );
+ }
+
+ /// Finds the key \p key and return the item found
+ /**
+ The function is an analog of \ref cds_nonintrusive_MichaelHashSet_rcu_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>
+ raw_ptr get_with( Q const& key, Less pred )
+ {
+ return bucket( key ).get_with( key, pred );
+ }
+
+ /// Clears the set (not atomic)
+ void clear()
+ {
+ for ( size_t i = 0; i < bucket_count(); ++i )
+ m_Buckets[i].clear();
+ m_ItemCounter.reset();
+ }
+
+ /// Checks if the set is empty
+ /**
+ @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns \p true.
+ */
+ bool empty() const
+ {
+ return size() == 0;
+ }
+
+ /// Returns item count in the set
+ /**
+ @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns 0.
+ */
+ size_t size() const
+ {
+ return m_ItemCounter;
+ }
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
+ /// Returns the size of hash table
+ /**
+ Since \p %MichaelHashSet cannot dynamically extend the hash table size,
+ the value returned is an constant depending on object initialization parameters;
+ see MichaelHashSet::MichaelHashSet for explanation.
+ */
+ size_t bucket_count() const
+ {
+ return m_nHashBitmask + 1;
+ }
+
+ protected:
+ //@cond
+ /// Calculates hash value of \p key
+ template <typename Q>
+ size_t hash_value( Q const& key ) const
+ {
+ return m_HashFunctor( key ) & m_nHashBitmask;
+ }
+
+ /// Returns the bucket (ordered list) for \p key
+ template <typename Q>
+ internal_bucket_type& bucket( Q const& key )
+ {
+ return m_Buckets[hash_value( key )];
+ }
+ template <typename Q>
+ internal_bucket_type const& bucket( Q const& key ) const
+ {
+ return m_Buckets[hash_value( key )];
+ }
+
+ template <typename Stat>
+ typename std::enable_if< Stat::empty >::type construct_bucket( internal_bucket_type* bkt )
+ {
+ new (bkt) internal_bucket_type;
+ }
+
+ template <typename Stat>
+ typename std::enable_if< !Stat::empty >::type construct_bucket( internal_bucket_type* bkt )
+ {
+ new (bkt) internal_bucket_type( m_Stat );
+ }
+
+ const_iterator get_const_begin() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count());
+ }
+ const_iterator get_const_end() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
+ }
+ //@endcond
+ };
+
+}} // namespace cds::container
+
+#endif // ifndef CDSLIB_CONTAINER_MICHAEL_SET_RCU_H
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