--- /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_INTRUSIVE_MICHAEL_SET_RCU_H
+#define CDSLIB_INTRUSIVE_MICHAEL_SET_RCU_H
+
+#include <cds/intrusive/details/michael_set_base.h>
+
+namespace cds { namespace intrusive {
+
+ /// Michael's hash set, \ref cds_urcu_desc "RCU" specialization
+ /** @ingroup cds_intrusive_map
+ \anchor cds_intrusive_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 bucket for hash set, for example, MichaelList, LazyList.
+ The intrusive ordered list implementation specifies the type \p T stored in the hash-set, the reclamation
+ schema \p GC used by hash-set, the comparison functor for the type \p T and other features specific for
+ the ordered list.
+ - \p Traits - type traits, default is \p michael_set::traits.
+ Instead of defining \p Traits struct you can use option-based syntax with \p michael_set::make_traits metafunction.
+
+ \par Usage
+ Before including <tt><cds/intrusive/michael_set_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.
+ For example, for \ref cds_urcu_general_buffered_gc "general-purpose buffered RCU" you should include:
+ \code
+ #include <cds/urcu/general_buffered.h>
+ #include <cds/intrusive/michael_list_rcu.h>
+ #include <cds/intrusive/michael_set_rcu.h>
+
+ struct Foo { ... };
+ // Hash functor for struct Foo
+ struct foo_hash {
+ size_t operator()( Foo const& foo ) const { return ... }
+ };
+
+ // Now, you can declare Michael's list for type Foo and default traits:
+ typedef cds::intrusive::MichaelList<cds::urcu::gc< general_buffered<> >, Foo > rcu_michael_list;
+
+ // Declare Michael's set with MichaelList as bucket type
+ typedef cds::intrusive::MichaelSet<
+ cds::urcu::gc< general_buffered<> >,
+ rcu_michael_list,
+ cds::intrusive::michael_set::make_traits<
+ cds::opt::::hash< foo_hash >
+ >::type
+ > rcu_michael_set;
+
+ // Declares hash set for 1000000 items with load factor 2
+ rcu_michael_set theSet( 1000000, 2 );
+
+ // Now you can use theSet object in many threads without any synchronization.
+ \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 schema
+ typedef OrderedList ordered_list; ///< type of ordered list used as a bucket implementation
+ typedef Traits traits; ///< Set traits
+
+ typedef typename ordered_list::value_type value_type; ///< type of value stored in the list
+ typedef typename ordered_list::key_comparator key_comparator; ///< key comparing functor
+ typedef typename ordered_list::disposer disposer; ///< Node disposer functor
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename ordered_list::stat stat; ///< Internal statistics
+#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");
+
+ protected:
+ //@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;
+
+ typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator;
+ //@endcond
+
+ public:
+ typedef typename internal_bucket_type::exempt_ptr exempt_ptr; ///< pointer to extracted node
+ typedef typename internal_bucket_type::raw_ptr raw_ptr; ///< Return type of \p get() member function and its derivatives
+
+ //@cond
+ typedef typename bucket_stat::stat stat;
+ //@endcond
+
+ private:
+ //@cond
+ hash m_HashFunctor; ///< Hash functor
+ size_t const m_nHashBitmask;
+ 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
+ /**
+ For iterator's features and requirements see \ref 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 cbegin();
+ }
+
+ /// Returns a forward const iterator addressing the first element in a set
+ const_iterator cbegin() const
+ {
+ return const_iterator( m_Buckets[0].cbegin(), m_Buckets, m_Buckets + bucket_count());
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
+ const_iterator end() const
+ {
+ return cend();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
+ const_iterator cend() const
+ {
+ return const_iterator( m_Buckets[bucket_count() - 1].cend(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
+ }
+ //@}
+
+ public:
+ /// Initialize hash set
+ /**
+ The Michael's hash set is an unbounded container, but its hash table is non-expandable.
+ At construction time you should pass estimated maximum item count and a load factor.
+ The load factor is average size of one bucket - a small number between 1 and 10.
+ The bucket is an ordered single-linked list, the complexity of searching in the bucket is linear <tt>O(nLoadFactor)</tt>.
+ The constructor 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: average size of 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 );
+ }
+
+ /// Clear hash set and destroy 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 inserts \p val in the set if it does not contain
+ an item with key equal to \p val.
+
+ Returns \p true if \p val is placed into the set, \p false otherwise.
+ */
+ bool insert( value_type& val )
+ {
+ bool bRet = bucket( val ).insert( val );
+ if ( bRet )
+ ++m_ItemCounter;
+ return bRet;
+ }
+
+ /// Inserts new node
+ /**
+ This function is intended for derived non-intrusive containers.
+
+ 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-field 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.
+
+ @warning For \ref cds_intrusive_MichaelList_rcu "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_intrusive_LazyList_rcu "LazyList" provides exclusive access to inserted item and does not require any node-level
+ synchronization.
+ */
+ template <typename Func>
+ bool insert( value_type& val, Func f )
+ {
+ bool bRet = bucket( val ).insert( 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, value_type& 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
+ If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
+ refers to the same thing.
+
+ The functor may change non-key fields of the \p item.
+
+ 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 Func>
+ std::pair<bool, bool> update( value_type& 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 Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( value_type& val, Func func )
+ {
+ return update( val, func, true );
+ }
+ //@endcond
+
+ /// Unlinks the item \p val from the set
+ /**
+ The function searches the item \p val in the set and unlink it from the set
+ if it is found and is equal to \p val.
+
+ The function returns \p true if success and \p false otherwise.
+ */
+ bool unlink( value_type& val )
+ {
+ bool bRet = bucket( val ).unlink( val );
+ if ( bRet )
+ --m_ItemCounter;
+ return bRet;
+ }
+
+ /// Deletes the item from the set
+ /** \anchor cds_intrusive_MichaelHashSet_rcu_erase
+ The function searches an item with key equal to \p key in the set,
+ unlinks it from the set, and returns \p true.
+ If the item with key equal to \p key is not found the function return \p false.
+
+ Note the hash functor should accept a parameter of type \p Q that may be not the same as \p value_type.
+ */
+ template <typename Q>
+ bool erase( Q const& key )
+ {
+ if ( bucket( key ).erase( key )) {
+ --m_ItemCounter;
+ return true;
+ }
+ return false;
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelHashSet_rcu_erase "erase(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>
+ bool erase_with( Q const& key, Less pred )
+ {
+ if ( bucket( key ).erase_with( key, pred )) {
+ --m_ItemCounter;
+ return true;
+ }
+ return false;
+ }
+
+ /// Deletes the item from the set
+ /** \anchor cds_intrusive_MichaelHashSet_rcu_erase_func
+ The function searches an item with key equal to \p key in the set,
+ call \p f functor with item found, and unlinks it from the set.
+ The \ref disposer specified in \p OrderedList class template parameter is called
+ by garbage collector \p GC asynchronously.
+
+ The \p Func interface is
+ \code
+ struct functor {
+ void operator()( value_type const& item );
+ };
+ \endcode
+
+ If the item with key equal to \p key is not found the function return \p false.
+
+ Note the hash functor should accept a parameter of type \p Q that can be not the same as \p value_type.
+ */
+ template <typename Q, typename Func>
+ bool erase( const Q& key, Func f )
+ {
+ if ( bucket( key ).erase( key, f )) {
+ --m_ItemCounter;
+ return true;
+ }
+ return false;
+ }
+
+ /// Deletes the item from the set using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelHashSet_rcu_erase_func "erase(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, typename Func>
+ bool erase_with( const Q& key, Less pred, Func f )
+ {
+ if ( bucket( key ).erase_with( key, pred, f )) {
+ --m_ItemCounter;
+ return true;
+ }
+ return false;
+ }
+
+ /// Extracts an item from the set
+ /** \anchor cds_intrusive_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 returns an empty \p exempt_ptr.
+
+ Depends on \p ordered_list you should or should not lock RCU before calling of this function:
+ - for the set based on \ref cds_intrusive_MichaelList_rcu "MichaelList" RCU should not be locked
+ - for the set based on \ref cds_intrusive_LazyList_rcu "LazyList" RCU should be locked
+
+ See ordered list implementation for details.
+
+ \code
+ #include <cds/urcu/general_buffered.h>
+ #include <cds/intrusive/michael_list_rcu.h>
+ #include <cds/intrusive/michael_set_rcu.h>
+
+ typedef cds::urcu::gc< general_buffered<> > rcu;
+ typedef cds::intrusive::MichaelList< rcu, Foo > rcu_michael_list;
+ typedef cds::intrusive::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
+
+ // Now, you can apply extract function
+ // 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:
+ // it invokes RCU retire_ptr function with the disposer you provided for rcu_michael_list.
+ 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;
+ }
+
+ /// 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
+
+ /// Find the key \p key
+ /** \anchor cds_intrusive_MichaelHashSet_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 can change non-key fields of \p item.
+ The functor does not serialize simultaneous access to the set \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 can 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 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_intrusive_MichaelHashSet_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 pred 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
+
+ /// Finds the key \p key and return the item found
+ /** \anchor cds_intrusive_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::intrusive::MichaelHashSet< your_template_parameters > hash_set;
+ hash_set theSet;
+ // ...
+ // Result of get() call
+ typename hash_set::raw_ptr ptr;
+ {
+ // Lock RCU
+ hash_set::rcu_lock lock;
+
+ ptr = theSet.get( 5 );
+ if ( ptr ) {
+ // Deal with ptr
+ //...
+ }
+ // Unlock RCU by rcu_lock destructor
+ // ptr can be reclaimed by disposer 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_intrusive_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 (non-atomic)
+ /**
+ The function unlink all items from the set.
+ The function is not atomic. It cleans up each bucket and then resets the item counter to zero.
+ If there are a thread that performs insertion while \p clear is working the result is undefined in general case:
+ <tt> empty() </tt> may return \p true but the set may contain item(s).
+ Therefore, \p clear may be used only for debugging purposes.
+
+ For each item the \p disposer is called after unlinking.
+ */
+ 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
+ /**
+ 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 the size of hash table
+ /**
+ Since %MichaelHashSet cannot dynamically extend the hash table size,
+ the value returned is an constant depending on object initialization parameters;
+ see \ref cds_intrusive_MichaelHashSet_hp "MichaelHashSet" for explanation.
+ */
+ size_t bucket_count() const
+ {
+ return m_nHashBitmask + 1;
+ }
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
+ private:
+ //@cond
+ 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 );
+ }
+
+ /// 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 )];
+ }
+ //@endcond
+ };
+
+}} // namespace cds::intrusive
+
+#endif // #ifndef CDSLIB_INTRUSIVE_MICHAEL_SET_NOGC_H
projects / c11concurrency-benchmarks.git / blobdiff