-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
#ifndef CDSLIB_CONTAINER_MICHAEL_MAP_NOGC_H
#define CDSLIB_CONTAINER_MICHAEL_MAP_NOGC_H
This specialization is so-called append-only when no item
reclamation may be performed. The class does not support deleting of map item.
- See \ref cds_nonintrusive_MichaelHashMap_hp "MichaelHashMap" for description of template parameters.
+ See @ref cds_nonintrusive_MichaelHashMap_hp "MichaelHashMap" for description of template parameters.
*/
template <
class OrderedList,
{
public:
typedef cds::gc::nogc gc; ///< No garbage collector
- typedef OrderedList bucket_type; ///< type of ordered list used as a bucket implementation
+ typedef OrderedList ordered_list; ///< type of ordered list used as a bucket implementation
typedef Traits traits; ///< Map traits
- typedef typename bucket_type::key_type key_type; ///< key type
- typedef typename bucket_type::mapped_type mapped_type; ///< type of value to be stored in the map
- typedef typename bucket_type::value_type value_type; ///< Pair used as the some functor's argument
+ typedef typename ordered_list::key_type key_type; ///< key type
+ typedef typename ordered_list::mapped_type mapped_type; ///< type of value to be stored in the map
+ typedef typename ordered_list::value_type value_type; ///< Pair used as the some functor's argument
- typedef typename bucket_type::key_comparator key_comparator; ///< key comparing functor
+ typedef typename ordered_list::key_comparator key_comparator; ///< key comparing functor
/// Hash functor for \ref key_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::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 traits::allocator > bucket_table_allocator;
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename ordered_list::stat stat; ///< Internal statistics
+#endif
- //@cond
- typedef cds::container::michael_map::implementation_tag implementation_tag;
- //@endcond
+ // 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 bucket_type::iterator bucket_iterator;
- typedef typename bucket_type::const_iterator bucket_const_iterator;
- //@endcond
+ typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat;
- protected:
- item_counter m_ItemCounter; ///< Item counter
- hash m_HashFunctor; ///< Hash functor
- 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:
+ /// Bucket table allocator
+ typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator;
+
+ typedef typename internal_bucket_type::iterator bucket_iterator;
+ typedef typename internal_bucket_type::const_iterator bucket_const_iterator;
+ //@endcond
+
+ public:
//@cond
- const size_t m_nHashBitmask;
+ typedef typename bucket_stat::stat stat;
//@endcond
protected:
//@cond
- /// Calculates hash value of \p key
- size_t hash_value( key_type const & key ) const
- {
- return m_HashFunctor( key ) & m_nHashBitmask;
- }
-
- /// Returns the bucket (ordered list) for \p key
- bucket_type& bucket( key_type const& key )
- {
- return m_Buckets[ hash_value( key ) ];
- }
+ const size_t m_nHashBitmask;
+ hash m_HashFunctor; ///< Hash functor
+ internal_bucket_type* m_Buckets; ///< bucket table
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
//@endcond
protected:
- /// Forward iterator
- /**
- \p IsConst - constness boolean flag
-
- The forward iterator for Michael's map is based on \p OrderedList forward iterator and has some features:
- - it has no post-increment operator, only pre-increment
- - it iterates items in unordered fashion
- */
+ //@cond
template <bool IsConst>
- class iterator_type: private cds::intrusive::michael_set::details::iterator< bucket_type, IsConst >
+ class iterator_type: private cds::intrusive::michael_set::details::iterator< internal_bucket_type, IsConst >
{
- //@cond
- typedef cds::intrusive::michael_set::details::iterator< bucket_type, IsConst > base_class;
+ typedef cds::intrusive::michael_set::details::iterator< internal_bucket_type, IsConst > base_class;
friend class MichaelHashMap;
- //@endcond
protected:
- //@cond
- //typedef typename base_class::bucket_type bucket_type;
typedef typename base_class::bucket_ptr bucket_ptr;
typedef typename base_class::list_iterator list_iterator;
- //typedef typename bucket_type::key_type key_type;
- //@endcond
-
public:
/// Value pointer type (const for const_iterator)
typedef typename cds::details::make_const_type<typename MichaelHashMap::mapped_type, IsConst>::pointer value_ptr;
typedef typename cds::details::make_const_type<typename MichaelHashMap::value_type, IsConst>::reference pair_ref;
protected:
- //@cond
iterator_type( list_iterator const& it, bucket_ptr pFirst, bucket_ptr pLast )
: base_class( it, pFirst, pLast )
{}
- //@endcond
public:
/// Default ctor
return !( *this == i );
}
};
-
+ //@endcond
public:
+ ///@name Forward iterators
+ //@{
/// Forward iterator
+ /**
+ The forward iterator for Michael's map is based on \p OrderedList forward iterator and has some features:
+ - it has no post-increment operator
+ - it iterates items in unordered fashion
+
+ 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 iterator_type< false > iterator;
/// Const forward iterator
*/
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
*/
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();
}
+
+ /// Returns a forward const iterator addressing the first element in a set
const_iterator cbegin() const
{
return get_const_begin();
}
- //@}
/// Returns an const iterator that addresses the location succeeding the last element in a set
- //@{
const_iterator end() const
{
return get_const_end();
}
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
const_iterator cend() const
{
return get_const_end();
}
- //@}
-
- private:
- //@cond
- const_iterator get_const_begin() const
- {
- return const_iterator( const_cast<bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count() );
- }
- const_iterator get_const_end() const
- {
- return const_iterator( const_cast<bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
- }
- //@endcond
+ //@}
public:
/// Initialize the map
- /** @copydetails cds_nonintrusive_MichaelHashMap_hp_ctor
+ /**
+ The Michael's hash map is non-expandable container. You should point the average count of items \p nMaxItemCount
+ when you create an object.
+ \p nLoadFactor parameter defines average count of items per bucket and it should be small number between 1 and 10.
+ Remember, since the bucket implementation is an ordered list, searching in the bucket is linear [<tt>O(nLoadFactor)</tt>].
+ Note, that many popular STL hash map implementation uses load factor 1.
+
+ The ctor defines hash table size as rounding <tt>nMacItemCount / nLoadFactor</tt> up to nearest power of two.
*/
MichaelHashMap(
size_t nMaxItemCount, ///< estimation of max item count in the hash set
size_t nLoadFactor ///< load factor: estimation of max number of items in the bucket
) : m_nHashBitmask( michael_map::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<gc, typename bucket_type::gc>::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<item_counter, atomicity::empty_item_counter>::value,
- "cds::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<bucket_stat>( it );
}
/// Clears hash set and destroys it
~MichaelHashMap()
{
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 with key and default value
template <typename K>
iterator insert( const K& key )
{
- bucket_type& refBucket = bucket( key );
+ internal_bucket_type& refBucket = bucket( key );
bucket_iterator it = refBucket.insert( key );
- if ( it != refBucket.end() ) {
+ if ( it != refBucket.end()) {
++m_ItemCounter;
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
}
return end();
template <typename K, typename V>
iterator insert( K const& key, V const& val )
{
- bucket_type& refBucket = bucket( key );
+ internal_bucket_type& refBucket = bucket( key );
bucket_iterator it = refBucket.insert( key, val );
- if ( it != refBucket.end() ) {
+ if ( it != refBucket.end()) {
++m_ItemCounter;
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
}
return end();
template <typename K, typename Func>
iterator insert_with( const K& key, Func func )
{
- bucket_type& refBucket = bucket( key );
+ internal_bucket_type& refBucket = bucket( key );
bucket_iterator it = refBucket.insert_with( key, func );
- if ( it != refBucket.end() ) {
+ if ( it != refBucket.end()) {
++m_ItemCounter;
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
}
return end();
template <typename K, typename... Args>
iterator emplace( K&& key, Args&&... args )
{
- bucket_type& refBucket = bucket( key );
+ internal_bucket_type& refBucket = bucket( key );
bucket_iterator it = refBucket.emplace( std::forward<K>(key), std::forward<Args>(args)... );
- if ( it != refBucket.end() ) {
+ if ( it != refBucket.end()) {
++m_ItemCounter;
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
}
return end();
}
- /// Ensures that the key \p key exists in the map
+ /// Updates the item
/**
- The operation inserts new item if the key \p key is not found in the map.
- Otherwise, the function returns an iterator that points to item found.
+ If \p key is not in the map and \p bAllowInsert is \p true, the function inserts a new item.
+ Otherwise, the function returns an iterator pointing to the item found.
- Returns <tt> std::pair<iterator, bool> </tt> where \p first is an iterator pointing to
- item found or inserted, \p second is true if new item has been added or \p false if the item
- already is in the list.
+ Returns <tt> std::pair<iterator, bool> </tt> where \p first is an iterator pointing to
+ item found or inserted (if inserting is not allowed and \p key is not found, the iterator will be \p end()),
+
+ \p second is true if new item has been added or \p false if the item
+ already is in the map.
@warning For \ref cds_nonintrusive_MichaelKVList_nogc "MichaelKVList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
\ref cds_nonintrusive_LazyKVList_nogc "LazyKVList" provides exclusive access to inserted item and does not require any node-level
synchronization.
*/
template <typename K>
- std::pair<iterator, bool> ensure( const K& key )
+ std::pair<iterator, bool> update( const K& key, bool bAllowInsert = true )
{
- bucket_type& refBucket = bucket( key );
- std::pair<bucket_iterator, bool> ret = refBucket.ensure( key );
+ internal_bucket_type& refBucket = bucket( key );
+ std::pair<bucket_iterator, bool> ret = refBucket.update( key, bAllowInsert );
if ( ret.second )
++m_ItemCounter;
-
- return std::make_pair( iterator( ret.first, &refBucket, m_Buckets + bucket_count() ), ret.second );
+ else if ( ret.first == refBucket.end())
+ return std::make_pair( end(), false );
+ return std::make_pair( iterator( ret.first, &refBucket, m_Buckets + bucket_count()), ret.second );
}
+ //@cond
+ template <typename K>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<iterator, bool> ensure( K const& key )
+ {
+ return update( key, true );
+ }
+ //@endcond
- /// Find the key \p key
- /** \anchor cds_nonintrusive_MichaelMap_nogc_find
-
+ /// Checks whether the map contains \p key
+ /**
The function searches the item with key equal to \p key
- and returns an iterator pointed to item found if the key is found,
- and \ref end() otherwise
+ and returns an iterator pointed to item found and \ref end() otherwise
*/
template <typename K>
- iterator find( const K& key )
+ iterator contains( K const& key )
{
- bucket_type& refBucket = bucket( key );
- bucket_iterator it = refBucket.find( key );
+ internal_bucket_type& refBucket = bucket( key );
+ bucket_iterator it = refBucket.contains( key );
- if ( it != refBucket.end() )
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ if ( it != refBucket.end())
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
return end();
}
+ //@cond
+ template <typename K>
+ CDS_DEPRECATED("deprecated, use contains()")
+ iterator find( K const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
- /// Finds the key \p val using \p pred predicate for searching
+ /// Checks whether the map contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_nonintrusive_MichaelMap_nogc_find "find(K const&)"
- but \p pred is used for key comparing.
+ 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 map.
+ \p pred must imply the same element order as the comparator used for building the map.
+ Hash functor specified in \p Traits should accept parameters of type \p K.
*/
template <typename K, typename Less>
- iterator find_with( const K& key, Less pred )
+ iterator contains( K const& key, Less pred )
{
- bucket_type& refBucket = bucket( key );
- bucket_iterator it = refBucket.find_with( key, pred );
+ internal_bucket_type& refBucket = bucket( key );
+ bucket_iterator it = refBucket.contains( key, pred );
- if ( it != refBucket.end() )
- return iterator( it, &refBucket, m_Buckets + bucket_count() );
+ if ( it != refBucket.end())
+ return iterator( it, &refBucket, m_Buckets + bucket_count());
return end();
}
+ //@cond
+ template <typename K, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ iterator find_with( K const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
/// Clears the map (not atomic)
void clear()
/// Checks whether 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 Michael's map implementation.
+ @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns \p true.
*/
bool empty() const
{
}
/// Returns item count in the map
+ /**
+ If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns 0.
+ */
size_t size() const
{
return m_ItemCounter;
}
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
/// Returns the size of hash table
/**
Since \p %MichaelHashMap cannot dynamically extend the hash table size,
{
return m_nHashBitmask + 1;
}
+
+ protected:
+ //@cond
+ /// Calculates hash value of \p key
+ template <typename K>
+ size_t hash_value( K const & key ) const
+ {
+ return m_HashFunctor( key ) & m_nHashBitmask;
+ }
+
+ /// Returns the bucket (ordered list) for \p key
+ template <typename K>
+ internal_bucket_type& bucket( K const& key )
+ {
+ return m_Buckets[hash_value( key )];
+ }
+ //@endcond
+
+ private:
+ //@cond
+ const_iterator get_const_begin() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count());
+ }
+ const_iterator get_const_end() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
+ }
+
+ template <typename Stat>
+ typename std::enable_if< Stat::empty >::type construct_bucket( internal_bucket_type* b )
+ {
+ new (b) internal_bucket_type;
+ }
+
+ template <typename Stat>
+ typename std::enable_if< !Stat::empty >::type construct_bucket( internal_bucket_type* b )
+ {
+ new (b) internal_bucket_type( m_Stat );
+ }
+ //@endcond
};
}} // namespace cds::container
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