--- /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_FELDMAN_HASHSET_RCU_H
+#define CDSLIB_CONTAINER_FELDMAN_HASHSET_RCU_H
+
+#include <cds/intrusive/feldman_hashset_rcu.h>
+#include <cds/container/details/feldman_hashset_base.h>
+
+namespace cds { namespace container {
+
+ /// Hash set based on multi-level array, \ref cds_urcu_desc "RCU" specialization
+ /** @ingroup cds_nonintrusive_set
+ @anchor cds_container_FeldmanHashSet_rcu
+
+ Source:
+ - [2013] Steven Feldman, Pierre LaBorde, Damian Dechev "Concurrent Multi-level Arrays:
+ Wait-free Extensible Hash Maps"
+
+ See algorithm short description @ref cds_intrusive_FeldmanHashSet_hp "here"
+
+ @note Two important things you should keep in mind when you're using \p %FeldmanHashSet:
+ - all keys must be fixed-size. It means that you cannot use \p std::string as a key for \p %FeldmanHashSet.
+ Instead, for the strings you should use well-known hashing algorithms like <a href="https://en.wikipedia.org/wiki/Secure_Hash_Algorithm">SHA1, SHA2</a>,
+ <a href="https://en.wikipedia.org/wiki/MurmurHash">MurmurHash</a>, <a href="https://en.wikipedia.org/wiki/CityHash">CityHash</a>
+ or its successor <a href="https://code.google.com/p/farmhash/">FarmHash</a> and so on, which
+ converts variable-length strings to fixed-length bit-strings, and use that hash as a key in \p %FeldmanHashSet.
+ - \p %FeldmanHashSet uses a perfect hashing. It means that if two different keys, for example, of type \p std::string,
+ have identical hash then you cannot insert both that keys in the set. \p %FeldmanHashSet does not maintain the key,
+ it maintains its fixed-size hash value.
+
+ The set supports @ref cds_container_FeldmanHashSet_iterators "bidirectional thread-safe iterators".
+
+ Template parameters:
+ - \p RCU - one of \ref cds_urcu_gc "RCU type"
+ - \p T - a value type to be stored in the set
+ - \p Traits - type traits, the structure based on \p feldman_hashset::traits or result of \p feldman_hashset::make_traits metafunction.
+ \p Traits is the mandatory argument because it has one mandatory type - an @ref feldman_hashset::traits::hash_accessor "accessor"
+ to hash value of \p T. The set algorithm does not calculate that hash value.
+
+ @note Before including <tt><cds/intrusive/feldman_hashset_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.
+
+ The set supports @ref cds_container_FeldmanHashSet_rcu_iterators "bidirectional thread-safe iterators"
+ with some restrictions.
+ */
+ template <
+ class RCU
+ , typename T
+#ifdef CDS_DOXYGEN_INVOKED
+ , class Traits = feldman_hashset::traits
+#else
+ , class Traits
+#endif
+ >
+ class FeldmanHashSet< cds::urcu::gc< RCU >, T, Traits >
+#ifdef CDS_DOXYGEN_INVOKED
+ : protected cds::intrusive::FeldmanHashSet< cds::urcu::gc< RCU >, T, Traits >
+#else
+ : protected cds::container::details::make_feldman_hashset< cds::urcu::gc< RCU >, T, Traits >::type
+#endif
+ {
+ //@cond
+ typedef cds::container::details::make_feldman_hashset< cds::urcu::gc< RCU >, T, Traits > maker;
+ typedef typename maker::type base_class;
+ //@endcond
+
+ public:
+ typedef cds::urcu::gc< RCU > gc; ///< RCU garbage collector
+ typedef T value_type; ///< type of value stored in the set
+ typedef Traits traits; ///< Traits template parameter, see \p feldman_hashset::traits
+
+ typedef typename base_class::hash_accessor hash_accessor; ///< Hash accessor functor
+ typedef typename base_class::hash_type hash_type; ///< Hash type deduced from \p hash_accessor return type
+ typedef typename base_class::hash_comparator hash_comparator; ///< hash compare functor based on \p opt::compare and \p opt::less option setter
+
+ typedef typename traits::item_counter item_counter; ///< Item counter type
+ typedef typename traits::allocator allocator; ///< Element allocator
+ typedef typename traits::node_allocator node_allocator; ///< Array node allocator
+ typedef typename traits::memory_model memory_model; ///< Memory model
+ typedef typename traits::back_off back_off; ///< Backoff strategy
+ typedef typename traits::stat stat; ///< Internal statistics type
+ typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
+ typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
+ static constexpr const bool c_bExtractLockExternal = false; ///< Group of \p extract_xxx functions does not require external locking
+ typedef typename base_class::exempt_ptr exempt_ptr; ///< pointer to extracted node
+
+ /// The size of hash_type in bytes, see \p feldman_hashset::traits::hash_size for explanation
+ static constexpr size_t const c_hash_size = base_class::c_hash_size;
+
+ /// Level statistics
+ typedef feldman_hashset::level_statistics level_statistics;
+
+ protected:
+ //@cond
+ typedef typename maker::cxx_node_allocator cxx_node_allocator;
+ typedef std::unique_ptr< value_type, typename maker::node_disposer > scoped_node_ptr;
+ //@endcond
+
+ public:
+ /// Creates empty set
+ /**
+ @param head_bits - 2<sup>head_bits</sup> specifies the size of head array, minimum is 4.
+ @param array_bits - 2<sup>array_bits</sup> specifies the size of array node, minimum is 2.
+
+ Equation for \p head_bits and \p array_bits:
+ \code
+ sizeof(hash_type) * 8 == head_bits + N * array_bits
+ \endcode
+ where \p N is multi-level array depth.
+ */
+ FeldmanHashSet( size_t head_bits = 8, size_t array_bits = 4 )
+ : base_class( head_bits, array_bits )
+ {}
+
+ /// Destructs the set and frees all data
+ ~FeldmanHashSet()
+ {}
+
+ /// Inserts new element
+ /**
+ The function creates an element with copy of \p val value and then inserts it into the set.
+
+ The type \p Q should contain as minimum the complete hash for the element.
+ 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.
+
+ The function locks RCU internally.
+ */
+ template <typename Q>
+ bool insert( Q const& val )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().New( val ));
+ if ( base_class::insert( *sp )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Inserts new element
+ /**
+ 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.
+
+ The function locks RCU internally.
+ */
+ template <typename Q, typename Func>
+ bool insert( Q const& val, Func f )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().New( val ));
+ if ( base_class::insert( *sp, f )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Updates the element
+ /**
+ The operation performs inserting or replacing 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, it is replaced with new item created from \p val
+ and previous item is disposed.
+ In both cases \p func functor is called.
+
+ The functor \p Func signature:
+ \code
+ struct my_functor {
+ void operator()( value_type& cur, value_type * prev );
+ };
+ \endcode
+ where:
+ - \p cur - current element
+ - \p prev - pointer to previous element with such hash. \p prev is \p nullptr
+ if \p cur was just inserted.
+
+ 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 the new item has been added or \p false if the item with key equal to \p val
+ already exists.
+ */
+ template <typename Q, typename Func>
+ std::pair<bool, bool> update( Q const& val, Func func, bool bInsert = true )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().New( val ));
+ std::pair<bool, bool> bRes = base_class::do_update( *sp, func, bInsert );
+ if ( bRes.first )
+ sp.release();
+ return bRes;
+ }
+
+ /// 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( cxx_node_allocator().MoveNew( std::forward<Args>(args)... ));
+ if ( base_class::insert( *sp )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Deletes the item from the set
+ /**
+ The function searches \p hash in the set,
+ deletes the item found, and returns \p true.
+ If that item is not found the function returns \p false.
+
+ RCU should not be locked. The function locks RCU internally.
+ */
+ bool erase( hash_type const& hash )
+ {
+ return base_class::erase( hash );
+ }
+
+ /// Deletes the item from the set
+ /**
+ The function searches \p hash in the set,
+ call \p f functor with item found, and deltes the element from the set.
+
+ The \p Func interface is
+ \code
+ struct functor {
+ void operator()( value_type& item );
+ };
+ \endcode
+
+ If \p hash is not found the function returns \p false.
+
+ RCU should not be locked. The function locks RCU internally.
+ */
+ template <typename Func>
+ bool erase( hash_type const& hash, Func f )
+ {
+ return base_class::erase( hash, f );
+ }
+
+ /// Extracts the item with specified \p hash
+ /**
+ The function searches \p hash 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 key equal to \p key is not found the function returns an empty \p exempt_ptr.
+
+ RCU \p synchronize method can be called. RCU should NOT be locked.
+ The function does not call the disposer for the item found.
+ The disposer will be implicitly invoked when the returned object is destroyed or when
+ its \p release() member function is called.
+ Example:
+ \code
+ typedef cds::container::FeldmanHashSet< cds::urcu::gc< cds::urcu::general_buffered<> >, foo, my_traits > set_type;
+ set_type theSet;
+ // ...
+
+ typename set_type::exempt_ptr ep( theSet.extract( 5 ));
+ if ( ep ) {
+ // Deal with ep
+ //...
+
+ // Dispose returned item.
+ ep.release();
+ }
+ \endcode
+ */
+ exempt_ptr extract( hash_type const& hash )
+ {
+ return base_class::extract( hash );
+ }
+
+ /// Finds an item by it's \p hash
+ /**
+ The function searches the item by \p hash and calls the functor \p f for item found.
+ The interface of \p Func functor is:
+ \code
+ struct functor {
+ void operator()( value_type& item );
+ };
+ \endcode
+ where \p item is the item found.
+
+ The functor may change non-key fields of \p item. Note that the functor is only guarantee
+ that \p item cannot be disposed during the 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 prevent unsafe item modifications.
+
+ The function returns \p true if \p hash is found, \p false otherwise.
+ */
+ template <typename Func>
+ bool find( hash_type const& hash, Func f )
+ {
+ return base_class::find( hash, f );
+ }
+
+ /// Checks whether the set contains \p hash
+ /**
+ The function searches the item by its \p hash
+ and returns \p true if it is found, or \p false otherwise.
+ */
+ bool contains( hash_type const& hash )
+ {
+ return base_class::contains( hash );
+ }
+
+ /// Finds an item by it's \p hash and returns the item found
+ /**
+ The function searches the item by its \p hash
+ and returns the pointer to the item found.
+ If \p hash is not found the function returns \p nullptr.
+
+ RCU should be locked before the function invocation.
+ Returned pointer is valid only while RCU is locked.
+
+ Usage:
+ \code
+ typedef cds::container::FeldmanHashSet< your_template_params > my_set;
+ my_set theSet;
+ // ...
+ {
+ // lock RCU
+ my_set::rcu_lock lock;
+
+ foo * p = theSet.get( 5 );
+ if ( p ) {
+ // Deal with p
+ //...
+ }
+ }
+ \endcode
+ */
+ value_type * get( hash_type const& hash )
+ {
+ return base_class::get( hash );
+ }
+
+ /// Clears the set (non-atomic)
+ /**
+ The function unlink all data node from the set.
+ The function is not atomic but is thread-safe.
+ After \p %clear() the set may not be empty because another threads may insert items.
+ */
+ void clear()
+ {
+ base_class::clear();
+ }
+
+ /// 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 the set implementation.
+ */
+ bool empty() const
+ {
+ return base_class::empty();
+ }
+
+ /// Returns item count in the set
+ size_t size() const
+ {
+ return base_class::size();
+ }
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return base_class::statistics();
+ }
+
+ /// Returns the size of head node
+ size_t head_size() const
+ {
+ return base_class::head_size();
+ }
+
+ /// Returns the size of the array node
+ size_t array_node_size() const
+ {
+ return base_class::array_node_size();
+ }
+
+ /// Collects tree level statistics into \p stat
+ /**
+ The function traverses the set and collects statistics for each level of the tree
+ into \p feldman_hashset::level_statistics struct. The element of \p stat[i]
+ represents statistics for level \p i, level 0 is head array.
+ The function is thread-safe and may be called in multi-threaded environment.
+
+ Result can be useful for estimating efficiency of hash functor you use.
+ */
+ void get_level_statistics(std::vector< feldman_hashset::level_statistics>& stat) const
+ {
+ base_class::get_level_statistics(stat);
+ }
+
+ public:
+ ///@name Thread-safe iterators
+ ///@{
+ /// Bidirectional iterator
+ /** @anchor cds_container_FeldmanHashSet_rcu_iterators
+ The set supports thread-safe iterators: you may iterate over the set in multi-threaded environment
+ under explicit RCU lock.
+ RCU lock requirement means that inserting or searching is allowed but you must not erase the items from the set
+ since erasing under RCU lock can lead to a deadlock. However, another thread can call \p erase() safely
+ while your thread is iterating.
+
+ A typical example is:
+ \code
+ struct foo {
+ uint32_t hash;
+ // ... other fields
+ uint32_t payload; // only for example
+ };
+ struct set_traits: cds::container::feldman_hashset::traits
+ {
+ struct hash_accessor {
+ uint32_t operator()( foo const& src ) const
+ {
+ retur src.hash;
+ }
+ };
+ };
+
+ typedef cds::urcu::gc< cds::urcu::general_buffered<>> rcu;
+ typedef cds::container::FeldmanHashSet< rcu, foo, set_traits > set_type;
+
+ set_type s;
+
+ // ...
+
+ // iterate over the set
+ {
+ // lock the RCU.
+ typename set_type::rcu_lock l; // scoped RCU lock
+
+ // traverse the set
+ for ( auto i = s.begin(); i != s.end(); ++i ) {
+ // deal with i. Remember, erasing is prohibited here!
+ i->payload++;
+ }
+ } // at this point RCU lock is released
+ \endcode
+
+ Each iterator object supports the common interface:
+ - dereference operators:
+ @code
+ value_type [const] * operator ->() noexcept
+ value_type [const] & operator *() noexcept
+ @endcode
+ - pre-increment and pre-decrement. Post-operators is not supported
+ - equality operators <tt>==</tt> and <tt>!=</tt>.
+ Iterators are equal iff they point to the same cell of the same array node.
+ Note that for two iterators \p it1 and \p it2 the condition <tt> it1 == it2 </tt>
+ does not entail <tt> &(*it1) == &(*it2) </tt>: welcome to concurrent containers
+
+ @note It is possible the item can be iterated more that once, for example, if an iterator points to the item
+ in an array node that is being splitted.
+ */
+ typedef typename base_class::iterator iterator;
+ typedef typename base_class::const_iterator const_iterator; ///< @ref cds_container_FeldmanHashSet_rcu_iterators "bidirectional const iterator" type
+ typedef typename base_class::reverse_iterator reverse_iterator; ///< @ref cds_container_FeldmanHashSet_rcu_iterators "bidirectional reverse iterator" type
+ typedef typename base_class::const_reverse_iterator const_reverse_iterator; ///< @ref cds_container_FeldmanHashSet_rcu_iterators "bidirectional reverse const iterator" type
+
+ /// Returns an iterator to the beginning of the set
+ iterator begin()
+ {
+ return base_class::begin();
+ }
+
+ /// Returns an const iterator to the beginning of the set
+ const_iterator begin() const
+ {
+ return base_class::begin();
+ }
+
+ /// Returns an const iterator to the beginning of the set
+ const_iterator cbegin()
+ {
+ return base_class::cbegin();
+ }
+
+ /// Returns an iterator to the element following the last element of the set. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ iterator end()
+ {
+ return base_class::end();
+ }
+
+ /// Returns a const iterator to the element following the last element of the set. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ const_iterator end() const
+ {
+ return base_class::end();
+ }
+
+ /// Returns a const iterator to the element following the last element of the set. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ const_iterator cend()
+ {
+ return base_class::cend();
+ }
+
+ /// Returns a reverse iterator to the first element of the reversed set
+ reverse_iterator rbegin()
+ {
+ return base_class::rbegin();
+ }
+
+ /// Returns a const reverse iterator to the first element of the reversed set
+ const_reverse_iterator rbegin() const
+ {
+ return base_class::rbegin();
+ }
+
+ /// Returns a const reverse iterator to the first element of the reversed set
+ const_reverse_iterator crbegin()
+ {
+ return base_class::crbegin();
+ }
+
+ /// Returns a reverse iterator to the element following the last element of the reversed set
+ /**
+ It corresponds to the element preceding the first element of the non-reversed container.
+ This element acts as a placeholder, attempting to access it results in undefined behavior.
+ */
+ reverse_iterator rend()
+ {
+ return base_class::rend();
+ }
+
+ /// Returns a const reverse iterator to the element following the last element of the reversed set
+ /**
+ It corresponds to the element preceding the first element of the non-reversed container.
+ This element acts as a placeholder, attempting to access it results in undefined behavior.
+ */
+ const_reverse_iterator rend() const
+ {
+ return base_class::rend();
+ }
+
+ /// Returns a const reverse iterator to the element following the last element of the reversed set
+ /**
+ It corresponds to the element preceding the first element of the non-reversed container.
+ This element acts as a placeholder, attempting to access it results in undefined behavior.
+ */
+ const_reverse_iterator crend()
+ {
+ return base_class::crend();
+ }
+ ///@}
+ };
+
+}} // namespace cds::container
+
+#endif // #ifndef CDSLIB_CONTAINER_FELDMAN_HASHSET_RCU_H
projects / c11concurrency-benchmarks.git / blobdiff