X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=cds%2Fintrusive%2Fmichael_set_rcu.h;h=2a0d9bd4eae353d796dcb041bbe95bd5dd42c97e;hb=e360657e258514a73ab99af0bd726c21d05156fc;hp=d155e93d8213490ae8df1a028b220d148d8ab186;hpb=2e8a58841ca3d7cc736cc9483b691cf70c3ecdb3;p=libcds.git diff --git a/cds/intrusive/michael_set_rcu.h b/cds/intrusive/michael_set_rcu.h index d155e93d..2a0d9bd4 100644 --- a/cds/intrusive/michael_set_rcu.h +++ b/cds/intrusive/michael_set_rcu.h @@ -1,10 +1,37 @@ -//$$CDS-header$$ +/* + This file is a part of libcds - Concurrent Data Structures library -#ifndef __CDS_INTRUSIVE_MICHAEL_SET_RCU_H -#define __CDS_INTRUSIVE_MICHAEL_SET_RCU_H + (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017 -#include -#include + 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 namespace cds { namespace intrusive { @@ -26,8 +53,8 @@ namespace cds { namespace intrusive { 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. See michael_set::type_traits for explanation. - Instead of defining \p Traits struct you can use option-based syntax with michael_set::make_traits metafunction. + - \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 you should include appropriate RCU header file, @@ -66,7 +93,7 @@ namespace cds { namespace intrusive { class RCU, class OrderedList, #ifdef CDS_DOXYGEN_INVOKED - class Traits = michael_set::type_traits + class Traits = michael_set::traits #else class Traits #endif @@ -74,73 +101,105 @@ namespace cds { namespace intrusive { class MichaelHashSet< cds::urcu::gc< RCU >, OrderedList, Traits > { public: - typedef OrderedList bucket_type ; ///< type of ordered list used as a bucket implementation - typedef Traits options ; ///< Traits template parameters + 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 bucket_type::value_type value_type ; ///< type of value stored in the list - typedef cds::urcu::gc< RCU > gc ; ///< RCU schema - typedef typename bucket_type::key_comparator key_comparator ; ///< key comparison functor - typedef typename bucket_type::disposer disposer ; ///< Node disposer functor + 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 options::hash >::type hash; - typedef typename options::item_counter item_counter ; ///< Item counter type + 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 - /// Bucket table allocator - typedef cds::details::Allocator< bucket_type, typename options::allocator > bucket_table_allocator; - - typedef typename bucket_type::rcu_lock rcu_lock ; ///< RCU scoped lock - typedef typename bucket_type::exempt_ptr exempt_ptr ; ///< pointer to extracted node + 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 CDS_CONSTEXPR_CONST bool c_bExtractLockExternal = bucket_type::c_bExtractLockExternal; + static CDS_CONSTEXPR const bool c_bExtractLockExternal = ordered_list::c_bExtractLockExternal; + + // GC and OrderedList::gc must be the same + static_assert(std::is_same::value, "GC and OrderedList::gc must be the same"); protected: - item_counter m_ItemCounter ; ///< Item counter - hash m_HashFunctor ; ///< Hash functor + //@cond + typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat; - bucket_type * m_Buckets ; ///< bucket table + 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; - private: - //@cond - const size_t m_nHashBitmask; + typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator; //@endcond - protected: + 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 - /// Calculates hash value of \p key - template - size_t hash_value( Q const& key ) const - { - return m_HashFunctor( key ) & m_nHashBitmask; - } + typedef typename bucket_stat::stat stat; + //@endcond - /// Returns the bucket (ordered list) for \p key - template - bucket_type& bucket( Q const& key ) - { - return m_Buckets[ hash_value( key ) ]; - } - template - bucket_type const& bucket( Q const& key ) const - { - return m_Buckets[ hash_value( key ) ]; - } + 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< bucket_type, false > iterator; + 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< bucket_type, true > const_iterator; + typedef michael_set::details::iterator< internal_bucket_type, true > const_iterator; /// Returns a forward iterator addressing the first element in a set /** @@ -148,7 +207,7 @@ namespace cds { namespace intrusive { */ iterator begin() { - return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() ); + 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 @@ -159,44 +218,33 @@ namespace cds { namespace intrusive { */ iterator end() { - return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() ); + 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(); + return cbegin(); } - const_iterator cbegin() + + /// Returns a forward const iterator addressing the first element in a set + const_iterator cbegin() const { - return get_const_begin(); + 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 get_const_end(); + return cend(); } - const_iterator cend() - { - return get_const_end(); - } - //@} - private: - //@cond - const_iterator get_const_begin() const - { - return const_iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() ); - } - const_iterator get_const_end() const + /// 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].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() ); + return const_iterator( m_Buckets[bucket_count() - 1].cend(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count()); } - //@endcond + //@} public: /// Initialize hash set @@ -211,21 +259,20 @@ namespace cds { namespace intrusive { 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())) { - // GC and OrderedList::gc must be the same - static_assert(( std::is_same::value ), "GC and OrderedList::gc must be the same"); - - // atomicity::empty_item_counter is not allowed as a item counter - static_assert(( !std::is_same::value ), "atomicity::empty_item_counter is not allowed as a item counter"); - - m_Buckets = bucket_table_allocator().NewArray( bucket_count() ); + for ( auto it = m_Buckets, itEnd = m_Buckets + bucket_count(); it != itEnd; ++it ) + construct_bucket( it ); } /// Clear hash set and destroy it ~MichaelHashSet() { clear(); - bucket_table_allocator().Delete( m_Buckets, bucket_count() ); + + 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 @@ -256,10 +303,12 @@ namespace cds { namespace intrusive { \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 and can be passed by reference - using boost::ref + 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 bool insert( value_type& val, Func f ) @@ -270,40 +319,51 @@ namespace cds { namespace intrusive { return bRet; } - /// Ensures that the \p item exists in the set + /// 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 into the set. + 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 - void func( bool bNew, value_type& item, value_type& val ); + 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 ensure function + - \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 can 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. - - You can pass \p func argument by value or by reference using boost::ref or cds::ref. + The functor may change non-key fields of the \p item. - Returns std::pair where \p first is \p true if operation is successfull, + Returns std::pair 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 - std::pair ensure( value_type& val, Func func ) + std::pair update( value_type& val, Func func, bool bAllowInsert = true ) { - std::pair bRet = bucket( val ).ensure( val, func ); - if ( bRet.first && bRet.second ) + std::pair bRet = bucket( val ).update( val, func, bAllowInsert ); + if ( bRet.second ) ++m_ItemCounter; return bRet; } + //@cond + template + CDS_DEPRECATED("ensure() is deprecated, use update()") + std::pair ensure( value_type& val, Func func ) + { + return update( val, func, true ); + } + //@endcond /// Unlinks the item \p val from the set /** @@ -322,16 +382,16 @@ namespace cds { namespace intrusive { /// Deletes the item from the set /** \anchor cds_intrusive_MichaelHashSet_rcu_erase - The function searches an item with key equal to \p val in the set, + 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 val is not found the function return \p false. + 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 - bool erase( Q const& val ) + bool erase( Q const& key ) { - if ( bucket( val ).erase( val )) { + if ( bucket( key ).erase( key )) { --m_ItemCounter; return true; } @@ -346,9 +406,9 @@ namespace cds { namespace intrusive { \p pred must imply the same element order as the comparator used for building the set. */ template - bool erase_with( Q const& val, Less pred ) + bool erase_with( Q const& key, Less pred ) { - if ( bucket( val ).erase_with( val, pred )) { + if ( bucket( key ).erase_with( key, pred )) { --m_ItemCounter; return true; } @@ -357,7 +417,7 @@ namespace cds { namespace intrusive { /// Deletes the item from the set /** \anchor cds_intrusive_MichaelHashSet_rcu_erase_func - The function searches an item with key equal to \p val in the set, + 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. @@ -368,16 +428,15 @@ namespace cds { namespace intrusive { void operator()( value_type const& item ); }; \endcode - The functor may be passed by reference with boost:ref - If the item with key equal to \p val is not found the function return \p false. + 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 - bool erase( const Q& val, Func f ) + bool erase( const Q& key, Func f ) { - if ( bucket( val ).erase( val, f )) { + if ( bucket( key ).erase( key, f )) { --m_ItemCounter; return true; } @@ -392,9 +451,9 @@ namespace cds { namespace intrusive { \p pred must imply the same element order as the comparator used for building the set. */ template - bool erase_with( const Q& val, Less pred, Func f ) + bool erase_with( const Q& key, Less pred, Func f ) { - if ( bucket( val ).erase_with( val, pred, f )) { + if ( bucket( key ).erase_with( key, pred, f )) { --m_ItemCounter; return true; } @@ -403,15 +462,15 @@ namespace cds { namespace intrusive { /// Extracts an item from the set /** \anchor cds_intrusive_MichaelHashSet_rcu_extract - The function searches an item with key equal to \p val in the set, - unlinks it from the set, places item pointer into \p dest argument, and returns \p true. - If the item with the key equal to \p val is not found the function return \p false. + 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 - @note The function does NOT call RCU read-side lock or synchronization, - and does NOT dispose the item found. It just excludes the item from the set - and returns a pointer to item found. - You should lock RCU before calling of the function, and you should synchronize RCU - outside the RCU lock before reusing returned pointer. + See ordered list implementation for details. \code #include @@ -425,17 +484,16 @@ namespace cds { namespace intrusive { rcu_michael_set theSet; // ... - rcu_michael_set::exempt_ptr p; - { - // first, we should lock RCU - rcu_michael_set::rcu_lock lock; - - // Now, you can apply extract function - // Note that you must not delete the item found inside the RCU lock - if ( theSet.extract( p, 10 )) { - // do something with p - ... - } + 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 @@ -445,88 +503,109 @@ namespace cds { namespace intrusive { \endcode */ template - bool extract( exempt_ptr& dest, Q const& val ) + exempt_ptr extract( Q const& key ) { - if ( bucket( val ).extract( dest, val )) { + exempt_ptr p( bucket( key ).extract( key )); + if ( p ) --m_ItemCounter; - return true; - } - return false; + return p; } /// Extracts an item from the set using \p pred predicate for searching /** - The function is an analog of \ref cds_intrusive_MichaelHashSet_rcu_extract "extract(exempt_ptr&, Q const&)" - but \p pred is used for key comparing. + 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 - bool extract_with( exempt_ptr& dest, Q const& val, Less pred ) + exempt_ptr extract_with( Q const& key, Less pred ) { - if ( bucket( val ).extract_with( dest, val, pred )) { + exempt_ptr p( bucket( key ).extract_with( key, pred )); + if ( p ) --m_ItemCounter; - return true; - } - return false; + return p; } - /// Finds the key \p val - /** \anchor cds_intrusive_MichaelHashSet_rcu_find_val - The function searches the item with key equal to \p val - and returns \p true if \p val found or \p false otherwise. + /// 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 - bool find( Q const& val ) const + bool contains( Q const& key ) + { + return bucket( key ).contains( key ); + } + //@cond + template + CDS_DEPRECATED("use contains()") + bool find( Q const& key ) { - return bucket( val ).find( val ); + return contains( key ); } + //@endcond - /// Finds the key \p val using \p pred predicate for searching + /// Checks whether the set contains \p key using \p pred predicate for searching /** - The function is an analog of \ref cds_intrusive_MichaelHashSet_rcu_find_val "find(Q const&)" - but \p pred is used for key comparing. + The function is an analog of contains( key ) 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. + \p Less must imply the same element order as the comparator used for building the set. */ template - bool find_with( Q const& val, Less pred ) const + bool contains( Q const& key, Less pred ) + { + return bucket( key ).contains( key, pred ); + } + //@cond + template + CDS_DEPRECATED("use contains()") + bool find_with( Q const& key, Less pred ) { - return bucket( val ).find_with( val, pred ); + return contains( key, pred ); } + //@endcond - /// Find the key \p val + /// Find the key \p key /** \anchor cds_intrusive_MichaelHashSet_rcu_find_func - The function searches the item with key equal to \p val and calls the functor \p f for item found. + 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& val ); + void operator()( value_type& item, Q& key ); }; \endcode - where \p item is the item found, \p val is the find function argument. - - You can pass \p f argument by value or by reference using boost::ref or cds::ref. + where \p item is the item found, \p key is the find 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 val argument is non-const since it can be used as \p f functor destination i.e., the functor + 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 val is found, \p false otherwise. + The function returns \p true if \p key is found, \p false otherwise. */ template - bool find( Q& val, Func f ) const + bool find( Q& key, Func f ) { - return bucket( val ).find( val, f ); + return bucket( key ).find( key, f ); } + //@cond + template + bool find( Q const& key, Func f ) + { + return bucket( key ).find( key, f ); + } + //@endcond - /// Finds the key \p val using \p pred predicate for searching + /// 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. @@ -534,56 +613,24 @@ namespace cds { namespace intrusive { \p pred must imply the same element order as the comparator used for building the set. */ template - bool find_with( Q& val, Less pred, Func f ) const - { - return bucket( val ).find_with( val, pred, f ); - } - - /// Find the key \p val - /** \anchor cds_intrusive_MichaelHashSet_rcu_find_cfunc - The function searches the item with key equal to \p val 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 const& val ); - }; - \endcode - where \p item is the item found, \p val is the find function argument. - - You can pass \p f argument by value or by reference using boost::ref or cds::ref. - - 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. - - 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 val is found, \p false otherwise. - */ - template - bool find( Q const& val, Func f ) const + bool find_with( Q& key, Less pred, Func f ) { - return bucket( val ).find( val, f ); + return bucket( key ).find_with( key, pred, f ); } - - /// Finds the key \p val using \p pred predicate for searching - /** - The function is an analog of \ref cds_intrusive_MichaelHashSet_rcu_find_cfunc "find(Q const&, 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. - */ + //@cond template - bool find_with( Q const& val, Less pred, Func f ) const + bool find_with( Q const& key, Less pred, Func f ) { - return bucket( val ).find_with( val, pred, f ); + return bucket( key ).find_with( key, pred, f ); } + //@endcond - /// Finds the key \p val and return the item found + /// 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 val and returns the pointer to item found. - If \p val is not found it returns \p nullptr. + 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. @@ -593,27 +640,29 @@ namespace cds { namespace intrusive { 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; - foo * pVal = theSet.get( 5 ); - if ( pVal ) { - // Deal with pVal + ptr = theSet.get( 5 ); + if ( ptr ) { + // Deal with ptr //... } // Unlock RCU by rcu_lock destructor - // pVal can be retired by disposer at any time after RCU has been unlocked + // ptr can be reclaimed by disposer at any time after RCU has been unlocked } \endcode */ template - value_type * get( Q const& val ) const + raw_ptr get( Q const& key ) { - return bucket( val ).get( val ); + return bucket( key ).get( key ); } - /// Finds the key \p val and return the item found + /// 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. @@ -623,9 +672,9 @@ namespace cds { namespace intrusive { \p pred must imply the same element order as the comparator used for building the set. */ template - value_type * get_with( Q const& val, Less pred ) const + raw_ptr get_with( Q const& key, Less pred ) { - return bucket( val ).get_with( val, pred ); + return bucket( key ).get_with( key, pred ); } /// Clears the set (non-atomic) @@ -648,8 +697,8 @@ namespace cds { namespace intrusive { /// Checks if the set is empty /** - Emptiness is checked by item counting: if item count is zero then the set is empty. - Thus, the correct item counting feature is an important part of Michael's set implementation. + @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter, + the function always returns \p true. */ bool empty() const { @@ -657,6 +706,10 @@ namespace cds { namespace intrusive { } /// 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; @@ -673,9 +726,47 @@ namespace cds { namespace intrusive { return m_nHashBitmask + 1; } + /// Returns const reference to internal statistics + stat const& statistics() const + { + return m_Stat; + } + + private: + //@cond + template + typename std::enable_if< Stat::empty >::type construct_bucket( internal_bucket_type * bkt ) + { + new (bkt) internal_bucket_type; + } + + template + 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 + size_t hash_value( Q const& key ) const + { + return m_HashFunctor( key ) & m_nHashBitmask; + } + + /// Returns the bucket (ordered list) for \p key + template + internal_bucket_type& bucket( Q const& key ) + { + return m_Buckets[hash_value( key )]; + } + template + internal_bucket_type const& bucket( Q const& key ) const + { + return m_Buckets[hash_value( key )]; + } + //@endcond }; }} // namespace cds::intrusive -#endif // #ifndef __CDS_INTRUSIVE_MICHAEL_SET_NOGC_H - +#endif // #ifndef CDSLIB_INTRUSIVE_MICHAEL_SET_NOGC_H