--- /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_HASHMAP_RCU_H
+#define CDSLIB_CONTAINER_FELDMAN_HASHMAP_RCU_H
+
+#include <cds/intrusive/feldman_hashset_rcu.h>
+#include <cds/container/details/feldman_hashmap_base.h>
+
+namespace cds { namespace container {
+
+ /// Hash map based on multi-level array
+ /** @ingroup cds_nonintrusive_map
+ @anchor cds_container_FeldmanHashMap_rcu
+
+ Source:
+ - [2013] Steven Feldman, Pierre LaBorde, Damian Dechev "Concurrent Multi-level Arrays:
+ Wait-free Extensible Hash Maps"
+
+ See algorithm short description @ref cds_container_FeldmanHashMap_hp "here"
+
+ @note Two important things you should keep in mind when you're using \p %FeldmanHashMap:
+ - all keys is converted to fixed-size bit-string by hash functor provided.
+ You can use variable-length keys, for example, \p std::string as a key for \p %FeldmanHashMap,
+ but real key in the map will be fixed-size hash values of your keys.
+ For the strings you may 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 such hash values will be the keys in \p %FeldmanHashMap.
+ If your key is fixed-sized the hash functor is optional, see \p feldman_hashmap::traits::hash for explanation and examples.
+ - \p %FeldmanHashMap 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 map. \p %FeldmanHashMap does not maintain the key,
+ it maintains its fixed-size hash value.
+
+ The map supports @ref cds_container_FeldmanHashMap_rcu_iterators "bidirectional thread-safe iterators".
+
+ Template parameters:
+ - \p RCU - one of \ref cds_urcu_gc "RCU type"
+ - \p Key - a key type to be stored in the map
+ - \p T - a value type to be stored in the map
+ - \p Traits - type traits, the structure based on \p feldman_hashmap::traits or result of \p feldman_hashmap::make_traits metafunction.
+
+ @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.
+ */
+ template <
+ class RCU
+ ,typename Key
+ ,typename T
+#ifdef CDS_DOXYGEN_INVOKED
+ ,class Traits = feldman_hashmap::traits
+#else
+ ,class Traits
+#endif
+ >
+ class FeldmanHashMap< cds::urcu::gc< RCU >, Key, T, Traits >
+#ifdef CDS_DOXYGEN_INVOKED
+ : protected cds::intrusive::FeldmanHashSet< cds::urcu::gc< RCU >, std::pair<Key const, T>, Traits >
+#else
+ : protected cds::container::details::make_feldman_hashmap< cds::urcu::gc< RCU >, Key, T, Traits >::type
+#endif
+ {
+ //@cond
+ typedef cds::container::details::make_feldman_hashmap< cds::urcu::gc< RCU >, Key, T, Traits > maker;
+ typedef typename maker::type base_class;
+ //@endcond
+ public:
+ typedef cds::urcu::gc< RCU > gc; ///< RCU garbage collector
+ typedef Key key_type; ///< Key type
+ typedef T mapped_type; ///< Mapped type
+ typedef std::pair< key_type const, mapped_type> value_type; ///< Key-value pair to be stored in the map
+ typedef Traits traits; ///< Map traits
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename traits::hash hasher; ///< Hash functor, see \p feldman_hashmap::traits::hash
+#else
+ typedef typename maker::hasher hasher;
+#endif
+
+ typedef typename maker::hash_type hash_type; ///< Hash type deduced from \p hasher return type
+ typedef typename base_class::hash_comparator hash_comparator; ///< hash compare functor based on \p Traits::compare and \p Traits::less
+ 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; ///< Back-off 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
+
+ /// Level statistics
+ typedef feldman_hashmap::level_statistics level_statistics;
+
+ protected:
+ //@cond
+ typedef typename maker::node_type node_type;
+ typedef typename maker::cxx_node_allocator cxx_node_allocator;
+ typedef std::unique_ptr< node_type, typename maker::node_disposer > scoped_node_ptr;
+ typedef typename base_class::check_deadlock_policy check_deadlock_policy;
+
+ struct node_cast
+ {
+ value_type * operator()(node_type * p) const
+ {
+ return p ? &p->m_Value : nullptr;
+ }
+ };
+
+ public:
+ /// pointer to extracted node
+ using exempt_ptr = cds::urcu::exempt_ptr< gc, node_type, value_type, typename base_class::disposer, node_cast >;
+
+ protected:
+ template <bool IsConst>
+ class bidirectional_iterator: public base_class::iterator_base
+ {
+ friend class FeldmanHashMap;
+ typedef typename base_class::iterator_base iterator_base;
+
+ protected:
+ static constexpr bool const c_bConstantIterator = IsConst;
+
+ public:
+ typedef typename std::conditional< IsConst, value_type const*, value_type*>::type value_ptr; ///< Value pointer
+ typedef typename std::conditional< IsConst, value_type const&, value_type&>::type value_ref; ///< Value reference
+
+ public:
+ bidirectional_iterator() noexcept
+ {}
+
+ bidirectional_iterator( bidirectional_iterator const& rhs ) noexcept
+ : iterator_base( rhs )
+ {}
+
+ bidirectional_iterator& operator=(bidirectional_iterator const& rhs) noexcept
+ {
+ iterator_base::operator=( rhs );
+ return *this;
+ }
+
+ bidirectional_iterator& operator++()
+ {
+ iterator_base::operator++();
+ return *this;
+ }
+
+ bidirectional_iterator& operator--()
+ {
+ iterator_base::operator--();
+ return *this;
+ }
+
+ value_ptr operator ->() const noexcept
+ {
+ node_type * p = iterator_base::pointer();
+ return p ? &p->m_Value : nullptr;
+ }
+
+ value_ref operator *() const noexcept
+ {
+ node_type * p = iterator_base::pointer();
+ assert( p );
+ return p->m_Value;
+ }
+
+ void release()
+ {
+ iterator_base::release();
+ }
+
+ template <bool IsConst2>
+ bool operator ==(bidirectional_iterator<IsConst2> const& rhs) const noexcept
+ {
+ return iterator_base::operator==( rhs );
+ }
+
+ template <bool IsConst2>
+ bool operator !=(bidirectional_iterator<IsConst2> const& rhs) const noexcept
+ {
+ return !( *this == rhs );
+ }
+
+ public: // for internal use only!
+ bidirectional_iterator( base_class const& set, typename base_class::array_node * pNode, size_t idx, bool )
+ : iterator_base( set, pNode, idx, false )
+ {}
+
+ bidirectional_iterator( base_class const& set, typename base_class::array_node * pNode, size_t idx )
+ : iterator_base( set, pNode, idx )
+ {}
+ };
+
+ /// Reverse bidirectional iterator
+ template <bool IsConst>
+ class reverse_bidirectional_iterator : public base_class::iterator_base
+ {
+ friend class FeldmanHashMap;
+ typedef typename base_class::iterator_base iterator_base;
+
+ public:
+ typedef typename std::conditional< IsConst, value_type const*, value_type*>::type value_ptr; ///< Value pointer
+ typedef typename std::conditional< IsConst, value_type const&, value_type&>::type value_ref; ///< Value reference
+
+ public:
+ reverse_bidirectional_iterator() noexcept
+ : iterator_base()
+ {}
+
+ reverse_bidirectional_iterator( reverse_bidirectional_iterator const& rhs ) noexcept
+ : iterator_base( rhs )
+ {}
+
+ reverse_bidirectional_iterator& operator=( reverse_bidirectional_iterator const& rhs) noexcept
+ {
+ iterator_base::operator=( rhs );
+ return *this;
+ }
+
+ reverse_bidirectional_iterator& operator++()
+ {
+ iterator_base::operator--();
+ return *this;
+ }
+
+ reverse_bidirectional_iterator& operator--()
+ {
+ iterator_base::operator++();
+ return *this;
+ }
+
+ value_ptr operator ->() const noexcept
+ {
+ node_type * p = iterator_base::pointer();
+ return p ? &p->m_Value : nullptr;
+ }
+
+ value_ref operator *() const noexcept
+ {
+ node_type * p = iterator_base::pointer();
+ assert( p );
+ return p->m_Value;
+ }
+
+ void release()
+ {
+ iterator_base::release();
+ }
+
+ template <bool IsConst2>
+ bool operator ==(reverse_bidirectional_iterator<IsConst2> const& rhs) const
+ {
+ return iterator_base::operator==( rhs );
+ }
+
+ template <bool IsConst2>
+ bool operator !=(reverse_bidirectional_iterator<IsConst2> const& rhs)
+ {
+ return !( *this == rhs );
+ }
+
+ public: // for internal use only!
+ reverse_bidirectional_iterator( base_class const& set, typename base_class::array_node * pNode, size_t idx, bool )
+ : iterator_base( set, pNode, idx, false )
+ {}
+
+ reverse_bidirectional_iterator( base_class const& set, typename base_class::array_node * pNode, size_t idx )
+ : iterator_base( set, pNode, idx, false )
+ {
+ iterator_base::backward();
+ }
+ };
+ //@endcond
+
+ public:
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef implementation_defined iterator; ///< @ref cds_container_FeldmanHashMap_rcu_iterators "bidirectional iterator" type
+ typedef implementation_defined const_iterator; ///< @ref cds_container_FeldmanHashMap_rcu_iterators "bidirectional const iterator" type
+ typedef implementation_defined reverse_iterator; ///< @ref cds_container_FeldmanHashMap_rcu_iterators "bidirectional reverse iterator" type
+ typedef implementation_defined const_reverse_iterator; ///< @ref cds_container_FeldmanHashMap_rcu_iterators "bidirectional reverse const iterator" type
+#else
+ typedef bidirectional_iterator<false> iterator;
+ typedef bidirectional_iterator<true> const_iterator;
+ typedef reverse_bidirectional_iterator<false> reverse_iterator;
+ typedef reverse_bidirectional_iterator<true> const_reverse_iterator;
+#endif
+
+ protected:
+ //@cond
+ hasher m_Hasher;
+ //@endcond
+
+ public:
+ /// Creates empty map
+ /**
+ @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.
+ */
+ FeldmanHashMap( size_t head_bits = 8, size_t array_bits = 4 )
+ : base_class( head_bits, array_bits )
+ {}
+
+ /// Destructs the map and frees all data
+ ~FeldmanHashMap()
+ {}
+
+ /// Inserts new element with key and default value
+ /**
+ The function creates an element with \p key and default value, and then inserts the node created into the map.
+
+ Preconditions:
+ - The \p key_type should be constructible from a value of type \p K.
+ In trivial case, \p K is equal to \p key_type.
+ - The \p mapped_type should be default-constructible.
+
+ Returns \p true if inserting successful, \p false otherwise.
+
+ The function locks RCU internally.
+ */
+ template <typename K>
+ bool insert( K&& key )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().MoveNew( m_Hasher, std::forward<K>(key)));
+ if ( base_class::insert( *sp )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Inserts new element
+ /**
+ The function creates a node with copy of \p val value
+ and then inserts the node created into the map.
+
+ Preconditions:
+ - The \p key_type should be constructible from \p key of type \p K.
+ - The \p value_type should be constructible from \p val of type \p V.
+
+ Returns \p true if \p val is inserted into the map, \p false otherwise.
+
+ The function locks RCU internally.
+ */
+ template <typename K, typename V>
+ bool insert( K&& key, V&& val )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().MoveNew( m_Hasher, std::forward<K>(key), std::forward<V>(val)));
+ if ( base_class::insert( *sp )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Inserts new element and initialize it by a functor
+ /**
+ This function inserts new element with key \p key and if inserting is successful then it calls
+ \p func functor with signature
+ \code
+ struct functor {
+ void operator()( value_type& item );
+ };
+ \endcode
+
+ The argument \p item of user-defined functor \p func is the reference
+ to the map's item inserted:
+ - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
+ - <tt>item.second</tt> is a reference to item's value that may be changed.
+
+ \p key_type should be constructible from value of type \p K.
+
+ The function allows to split creating of new item into two part:
+ - create item from \p key;
+ - insert new item into the map;
+ - if inserting is successful, initialize the value of item by calling \p func functor
+
+ This can be useful if complete initialization of object of \p value_type is heavyweight and
+ it is preferable that the initialization should be completed only if inserting is successful.
+
+ The function locks RCU internally.
+ */
+ template <typename K, typename Func>
+ bool insert_with( K&& key, Func func )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().MoveNew( m_Hasher, std::forward<K>(key)));
+ if ( base_class::insert( *sp, [&func]( node_type& item ) { func( item.m_Value ); } )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// For key \p key 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.
+
+ The function locks RCU internally.
+ */
+ template <typename K, typename... Args>
+ bool emplace( K&& key, Args&&... args )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().MoveNew( m_Hasher, std::forward<K>(key), std::forward<Args>(args)... ));
+ if ( base_class::insert( *sp )) {
+ sp.release();
+ return true;
+ }
+ return false;
+ }
+
+ /// Updates data by \p key
+ /**
+ The operation performs inserting or replacing the element with lock-free manner.
+
+ If the \p key not found in the map, then the new item created from \p key
+ will be inserted into the map iff \p bInsert is \p true
+ (note that in this case the \ref key_type should be constructible from type \p K).
+ Otherwise, if \p key is found, it is replaced with a new item created from
+ \p key.
+ The functor \p Func signature:
+ \code
+ struct my_functor {
+ void operator()( value_type& item, value_type * old );
+ };
+ \endcode
+ where:
+ - \p item - item of the map
+ - \p old - old item of the map, if \p nullptr - the new item was inserted
+
+ The functor may change any fields of the \p item.second.
+
+ 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 \p key already exists.
+
+ The function locks RCU internally.
+
+ @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
+ */
+ template <typename K, typename Func>
+ std::pair<bool, bool> update( K&& key, Func func, bool bInsert = true )
+ {
+ scoped_node_ptr sp( cxx_node_allocator().MoveNew( m_Hasher, std::forward<K>(key)));
+ std::pair<bool, bool> result = base_class::do_update( *sp,
+ [&func]( node_type& node, node_type * old ) { func( node.m_Value, old ? &old->m_Value : nullptr );},
+ bInsert );
+ if ( result.first )
+ sp.release();
+ return result;
+ }
+
+ /// Delete \p key from the map
+ /**
+ \p key_type must be constructible from value of type \p K.
+ The function deletes the element with hash value equal to <tt>hash( key_type( key ))</tt>
+
+ Return \p true if \p key is found and deleted, \p false otherwise.
+
+ RCU should not be locked. The function locks RCU internally.
+ */
+ template <typename K>
+ bool erase( K const& key )
+ {
+ return base_class::erase(m_Hasher(key_type(key)));
+ }
+
+ /// Delete \p key from the map
+ /**
+ The function searches an item with hash value equal to <tt>hash( key_type( key ))</tt>,
+ 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& item) { ... }
+ };
+ \endcode
+ where \p item is the element found.
+
+ \p key_type must be constructible from value of type \p K.
+
+ Return \p true if key is found and deleted, \p false otherwise
+
+ RCU should not be locked. The function locks RCU internally.
+ */
+ template <typename K, typename Func>
+ bool erase( K const& key, Func f )
+ {
+ return base_class::erase(m_Hasher(key_type(key)), [&f]( node_type& node) { f( node.m_Value ); });
+ }
+
+ /// Extracts the item from the map with specified \p key
+ /**
+ The function searches an item with key equal to <tt>hash( key_type( key ))</tt> in the map,
+ unlinks it from the map, and returns a guarded pointer to the item found.
+ If \p key is not found the function returns an empty guarded pointer.
+
+ 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::FeldmanHashMap< cds::urcu::gc< cds::urcu::general_buffered<>>, int, foo, my_traits > map_type;
+ map_type theMap;
+ // ...
+
+ typename map_type::exempt_ptr ep( theMap.extract( 5 ));
+ if ( ep ) {
+ // Deal with ep
+ //...
+
+ // Dispose returned item.
+ ep.release();
+ }
+ \endcode
+ */
+ template <typename K>
+ exempt_ptr extract( K const& key )
+ {
+ check_deadlock_policy::check();
+
+ node_type * p;
+ {
+ rcu_lock rcuLock;
+ p = base_class::do_erase( m_Hasher( key_type(key)), [](node_type const&) -> bool {return true;});
+ }
+ return exempt_ptr(p);
+ }
+
+ /// Checks whether the map contains \p key
+ /**
+ The function searches the item by its hash that is equal to <tt>hash( key_type( key ))</tt>
+ and returns \p true if it is found, or \p false otherwise.
+ */
+ template <typename K>
+ bool contains( K const& key )
+ {
+ return base_class::contains( m_Hasher( key_type( key )));
+ }
+
+ /// Find the key \p key
+ /**
+
+ The function searches the item by its hash that is equal to <tt>hash( key_type( key ))</tt>
+ 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 \p item.second.
+
+ The function returns \p true if \p key is found, \p false otherwise.
+ */
+ template <typename K, typename Func>
+ bool find( K const& key, Func f )
+ {
+ return base_class::find( m_Hasher( key_type( key )), [&f](node_type& node) { f( node.m_Value );});
+ }
+
+ /// Finds the key \p key and return 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::FeldmanHashMap< your_template_params > my_map;
+ my_map theMap;
+ // ...
+ {
+ // lock RCU
+ my_map::rcu_lock;
+
+ foo * p = theMap.get( 5 );
+ if ( p ) {
+ // Deal with p
+ //...
+ }
+ }
+ \endcode
+ */
+ template <typename K>
+ value_type * get( K const& key )
+ {
+ node_type * p = base_class::get( m_Hasher( key_type( key )));
+ return p ? &p->m_Value : nullptr;
+ }
+
+ /// Clears the map (non-atomic)
+ /**
+ The function unlink all data node from the map.
+ The function is not atomic but is thread-safe.
+ After \p %clear() the map may not be empty because another threads may insert items.
+ */
+ void clear()
+ {
+ base_class::clear();
+ }
+
+ /// Checks if the map is empty
+ /**
+ Emptiness is checked by item counting: if item count is zero then the map is empty.
+ Thus, the correct item counting feature is an important part of the map implementation.
+ */
+ bool empty() const
+ {
+ return base_class::empty();
+ }
+
+ /// Returns item count in the map
+ 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_hashmap::level_statistics>& stat) const
+ {
+ base_class::get_level_statistics(stat);
+ }
+
+ public:
+ ///@name Thread-safe iterators
+ /** @anchor cds_container_FeldmanHashMap_rcu_iterators
+ The map supports thread-safe iterators: you may iterate over the map 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 map
+ 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 {
+ // ... other fields
+ uint32_t payload; // only for example
+ };
+ typedef cds::urcu::gc< cds::urcu::general_buffered<>> rcu;
+ typedef cds::container::FeldmanHashMap< rcu, std::string, foo> map_type;
+
+ map_type m;
+
+ // ...
+
+ // iterate over the map
+ {
+ // lock the RCU.
+ typename set_type::rcu_lock l; // scoped RCU lock
+
+ // traverse the map
+ for ( auto i = m.begin(); i != s.end(); ++i ) {
+ // deal with i. Remember, erasing is prohibited here!
+ i->second.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.
+ */
+ ///@{
+ /// Returns an iterator to the beginning of the map
+ iterator begin()
+ {
+ return base_class::template init_begin<iterator>();
+ }
+
+ /// Returns an const iterator to the beginning of the map
+ const_iterator begin() const
+ {
+ return base_class::template init_begin<const_iterator>();
+ }
+
+ /// Returns an const iterator to the beginning of the map
+ const_iterator cbegin()
+ {
+ return base_class::template init_begin<const_iterator>();
+ }
+
+ /// Returns an iterator to the element following the last element of the map. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ iterator end()
+ {
+ return base_class::template init_end<iterator>();
+ }
+
+ /// Returns a const iterator to the element following the last element of the map. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ const_iterator end() const
+ {
+ return base_class::template init_end<const_iterator>();
+ }
+
+ /// Returns a const iterator to the element following the last element of the map. This element acts as a placeholder; attempting to access it results in undefined behavior.
+ const_iterator cend()
+ {
+ return base_class::template init_end<const_iterator>();
+ }
+
+ /// Returns a reverse iterator to the first element of the reversed map
+ reverse_iterator rbegin()
+ {
+ return base_class::template init_rbegin<reverse_iterator>();
+ }
+
+ /// Returns a const reverse iterator to the first element of the reversed map
+ const_reverse_iterator rbegin() const
+ {
+ return base_class::template init_rbegin<const_reverse_iterator>();
+ }
+
+ /// Returns a const reverse iterator to the first element of the reversed map
+ const_reverse_iterator crbegin()
+ {
+ return base_class::template init_rbegin<const_reverse_iterator>();
+ }
+
+ /// Returns a reverse iterator to the element following the last element of the reversed map
+ /**
+ 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::template init_rend<reverse_iterator>();
+ }
+
+ /// Returns a const reverse iterator to the element following the last element of the reversed map
+ /**
+ 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::template init_rend<const_reverse_iterator>();
+ }
+
+ /// Returns a const reverse iterator to the element following the last element of the reversed map
+ /**
+ 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::template init_rend<const_reverse_iterator>();
+ }
+ ///@}
+ };
+}} // namespace cds::container
+
+#endif // #ifndef CDSLIB_CONTAINER_FELDMAN_HASHMAP_RCU_H
projects / c11concurrency-benchmarks.git / blobdiff