-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
-#ifndef __CDS_CONTAINER_MICHAEL_MAP_H
-#define __CDS_CONTAINER_MICHAEL_MAP_H
+ (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_H
+#define CDSLIB_CONTAINER_MICHAEL_MAP_H
#include <cds/container/details/michael_map_base.h>
+#include <cds/container/details/iterable_list_base.h>
#include <cds/details/allocator.h>
namespace cds { namespace container {
- \p GC - Garbage collector used. You may use any \ref cds_garbage_collector "Garbage collector"
from the \p libcds library.
Note the \p GC must be the same as the GC used for \p OrderedList
- - \p OrderedList - ordered key-value list implementation used as bucket for hash map, for example, MichaelKVList
- or LazyKVList. The ordered list implementation specifies the \p Key and \p Value types stored in the hash-map,
- the reclamation schema \p GC used by hash-map, the comparison functor for the type \p Key and other features
- specific for the ordered list.
- - \p Traits - type traits. See michael_map::type_traits for explanation.
-
- Instead of defining \p Traits struct you may use option-based syntax with \p michael_map::make_traits metafunction
- (this metafunction is a synonym for michael_set::make_traits).
- For \p michael_map::make_traits the following option may be used:
- - opt::hash - mandatory option, specifies hash functor.
- - opt::item_counter - optional, specifies item counting policy. See michael_map::type_traits for explanation.
- - opt::allocator - optional, bucket table allocator. Default is \ref CDS_DEFAULT_ALLOCATOR.
-
- Many of the class function take a key argument of type \p K that in general is not \ref key_type.
+ - \p OrderedList - ordered key-value list implementation used as bucket for hash map, for example, \p MichaelKVList,
+ \p LazyKVList, \p IterableKVList. The ordered list implementation specifies the \p Key and \p Value types
+ stored in the hash-map, the reclamation schema \p GC used by hash-map, the comparison functor for the type \p Key
+ and other features specific for the ordered list.
+ - \p Traits - map traits, default is \p michael_map::traits.
+ Instead of defining \p Traits struct you may use option-based syntax with \p michael_map::make_traits metafunction.
+
+ Many of the class function take a key argument of type \p K that in general is not \p key_type.
\p key_type and an argument of template type \p K must meet the following requirements:
- \p key_type should be constructible from value of type \p K;
- the hash functor should be able to calculate correct hash value from argument \p key of type \p K:
- <tt> hash( key_type(key) ) == hash( key ) </tt>
+ <tt> hash( key_type(key)) == hash( key ) </tt>
- values of type \p key_type and \p K should be comparable
There are the specializations:
- - for \ref cds_urcu_desc "RCU" - declared in <tt>cd/container/michael_map_rcu.h</tt>,
+ - for \ref cds_urcu_desc "RCU" - declared in <tt>cds/container/michael_map_rcu.h</tt>,
see \ref cds_nonintrusive_MichaelHashMap_rcu "MichaelHashMap<RCU>".
- - for \ref cds::gc::nogc declared in <tt>cds/container/michael_map_nogc.h</tt>,
+ - for \p cds::gc::nogc declared in <tt>cds/container/michael_map_nogc.h</tt>,
see \ref cds_nonintrusive_MichaelHashMap_nogc "MichaelHashMap<gc::nogc>".
- <b>Iterators</b>
-
- The class supports a forward iterator (\ref iterator and \ref const_iterator).
- The iteration is unordered.
- The iterator object is thread-safe: the element pointed by the iterator object is guarded,
- so, the element cannot be reclaimed while the iterator object is alive.
- However, passing an iterator object between threads is dangerous.
-
- \warning Due to concurrent nature of Michael's set it is not guarantee that you can iterate
- all elements in the set: any concurrent deletion can exclude the element
- pointed by the iterator from the set, and your iteration can be terminated
- before end of the set. Therefore, such iteration is more suitable for debugging purpose only
-
- Remember, each iterator object requires an additional hazard pointer, that may be
- a limited resource for \p GC like \p gc::HP (for gc::PTB the count of
- guards is unlimited).
-
- The iterator class supports the following minimalistic interface:
- \code
- struct iterator {
- // Default ctor
- iterator();
-
- // Copy ctor
- iterator( iterator const& s);
-
- value_type * operator ->() const;
- value_type& operator *() const;
-
- // Pre-increment
- iterator& operator ++();
-
- // Copy assignment
- iterator& operator = (const iterator& src);
-
- bool operator ==(iterator const& i ) const;
- bool operator !=(iterator const& i ) const;
- };
- \endcode
- Note, the iterator object returned by \ref end, \p cend member functions points to \p nullptr and should not be dereferenced.
-
\anchor cds_nonintrusive_MichaelHashMap_how_touse
<b>How to use</b>
Suppose, you want to make \p int to \p int map for Hazard Pointer garbage collector. You should
- choose suitable ordered list class that will be used as a bucket for the map; it may be MichaelKVList.
+ choose suitable ordered list class that will be used as a bucket for the map; it may be \p MichaelKVList.
\code
#include <cds/container/michael_kvlist_hp.h> // MichaelKVList for gc::HP
- #include <cds/container/michael_map.h> // MIchaelHashMap
+ #include <cds/container/michael_map.h> // MichaelHashMap
// List traits based on std::less predicate
- struct list_traits: public cds::container::michael_list::type_traits
+ struct list_traits: public cds::container::michael_list::traits
{
typedef std::less<int> less;
};
typedef cds::container::MichaelKVList< cds::gc::HP, int, int, list_traits> int2int_list;
// Map traits
- struct map_traits: public cds::container::michael_map::type_traits
+ struct map_traits: public cds::container::michael_map::traits
{
struct hash {
size_t operator()( int i ) const
You may use option-based declaration:
\code
#include <cds/container/michael_kvlist_hp.h> // MichaelKVList for gc::HP
- #include <cds/container/michael_map.h> // MIchaelHashMap
+ #include <cds/container/michael_map.h> // MichaelHashMap
// Ordered list
typedef cds::container::MichaelKVList< cds::gc::HP, int, int,
class GC,
class OrderedList,
#ifdef CDS_DOXYGEN_INVOKED
- class Traits = michael_map::type_traits
+ class Traits = michael_map::traits
#else
class Traits
#endif
class MichaelHashMap
{
public:
- typedef OrderedList bucket_type ; ///< type of ordered list used as a bucket implementation
- typedef Traits options ; ///< Traits template parameters
+ typedef GC gc; ///< Garbage collector
+ typedef OrderedList ordered_list; ///< type of ordered list to be used as a bucket
+ typedef Traits traits; ///< Map traits
- typedef typename bucket_type::key_type key_type ; ///< key type
- typedef typename bucket_type::mapped_type mapped_type ; ///< value type
- typedef typename bucket_type::value_type value_type ; ///< key/value pair stored in the map
+ typedef typename ordered_list::key_type key_type; ///< key type
+ typedef typename ordered_list::mapped_type mapped_type; ///< value type
+ typedef typename ordered_list::value_type value_type; ///< key/value pair stored in the map
+ typedef typename traits::allocator allocator; ///< Bucket table allocator
- typedef GC gc ; ///< Garbage collector
- typedef typename bucket_type::key_comparator key_comparator ; ///< key compare functor
+ typedef typename ordered_list::key_comparator key_comparator; ///< key compare functor
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename ordered_list::stat stat; ///< Internal statistics
+ /// Guarded pointer - a result of \p get() and \p extract() functions
+ typedef typename ordered_list::guarded_ptr guarded_ptr;
+#endif
/// Hash functor for \ref key_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
- /// Bucket table allocator
- typedef cds::details::Allocator< bucket_type, typename options::allocator > bucket_table_allocator;
- typedef typename bucket_type::guarded_ptr guarded_ptr; ///< Guarded pointer
+ // 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:
- item_counter m_ItemCounter ; ///< Item counter
- hash m_HashFunctor ; ///< Hash functor
-
- bucket_type * m_Buckets ; ///< bucket table
+ static CDS_CONSTEXPR const size_t c_nHazardPtrCount = ordered_list::c_nHazardPtrCount; ///< Count of hazard pointer required
- private:
//@cond
- const size_t m_nHashBitmask;
+ typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat;
+
+ typedef typename ordered_list::template rebind_traits<
+ cds::opt::item_counter< cds::atomicity::empty_item_counter >
+ , cds::opt::stat< typename bucket_stat::wrapped_stat >
+ >::type internal_bucket_type;
+
+ typedef typename internal_bucket_type::guarded_ptr guarded_ptr;
+ typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator;
+ typedef typename bucket_stat::stat stat;
//@endcond
protected:
- /// Calculates hash value of \p key
- template <typename Q>
- size_t hash_value( Q const& key ) const
- {
- return m_HashFunctor( key ) & m_nHashBitmask;
- }
-
- /// Returns the bucket (ordered list) for \p key
- template <typename Q>
- bucket_type& bucket( Q const& key )
- {
- return m_Buckets[ hash_value( key ) ];
- }
+ //@cond
+ const size_t m_nHashBitmask;
+ internal_bucket_type* m_Buckets; ///< bucket table
+ hash m_HashFunctor; ///< Hash functor
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
+ //@endcond
protected:
//@cond
/// Forward iterator
template <bool IsConst>
- class iterator_type: private cds::intrusive::michael_set::details::iterator< bucket_type, IsConst >
+ class iterator_type: protected cds::intrusive::michael_set::details::iterator< internal_bucket_type, IsConst >
{
- 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;
protected:
/// Equality operator
template <bool C>
- bool operator ==(iterator_type<C> const& i )
+ bool operator ==(iterator_type<C> const& i ) const
{
return base_class::operator ==( i );
}
/// Equality operator
template <bool C>
- bool operator !=(iterator_type<C> const& i )
+ bool operator !=(iterator_type<C> const& i ) const
{
return !( *this == i );
}
//@endcond
public:
+ ///@name Forward iterators (only for debugging purpose)
+ //@{
/// Forward iterator
+ /**
+ The forward iterator for Michael's map has some features:
+ - it has no post-increment operator
+ - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
+ For some GC (like as \p gc::HP), a guard is a limited resource per thread, so an exception (or assertion) "no free guard"
+ may be thrown if the limit of guard count per thread is exceeded.
+ - The iterator cannot be moved across thread boundary because it contains thread-private GC's guard.
+
+ Iterator thread safety depends on type of \p OrderedList:
+ - for \p MichaelKVList and \p LazyKVList: iterator guarantees safety even if you delete the item that iterator points to
+ because that item is guarded by hazard pointer.
+ However, in case of concurrent deleting operations it is no guarantee that you iterate all item in the map.
+ Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
+ Use this iterator on the concurrent container for debugging purpose only.
+ - for \p IterableList: iterator is thread-safe. You may use it freely in concurrent environment.
+
+ 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
+
+ @note The iterator object returned by \p end(), \p cend() member functions points to \p nullptr and should not be dereferenced.
+ */
typedef iterator_type< false > iterator;
/// Const forward iterator
*/
iterator begin()
{
- return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() );
+ return iterator( bucket_begin()->begin(), bucket_begin(), bucket_end());
}
/// Returns an iterator that addresses the location succeeding the last element in a map
*/
iterator end()
{
- return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
+ return iterator( bucket_end()[-1].end(), bucket_end() - 1, bucket_end());
}
/// Returns a forward const iterator addressing the first element in a map
- //@{
const_iterator begin() const
{
return get_const_begin();
}
- const_iterator cbegin()
+ /// Returns a forward const iterator addressing the first element in a map
+ const_iterator cbegin() const
{
return get_const_begin();
}
- //@}
/// Returns an const iterator that addresses the location succeeding the last element in a map
- //@{
const_iterator end() const
{
return get_const_end();
}
- const_iterator cend()
+ /// Returns an const iterator that addresses the location succeeding the last element in a map
+ 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:
/// Initializes the map
- /**
+ /** @anchor 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.
MichaelHashMap(
size_t nMaxItemCount, ///< estimation of max item count in the hash map
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_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 ), "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 map 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
Returns \p true if inserting successful, \p false otherwise.
*/
template <typename K>
- bool insert( const K& key )
+ bool insert( K&& key )
{
- const bool bRet = bucket( key ).insert( key );
+ const bool bRet = bucket( key ).insert( std::forward<K>( key ));
if ( bRet )
++m_ItemCounter;
return bRet;
Returns \p true if \p val is inserted into the map, \p false otherwise.
*/
template <typename K, typename V>
- bool insert( K const& key, V const& val )
+ bool insert( K&& key, V&& val )
{
- const bool bRet = bucket( key ).insert( key, val );
+ const bool bRet = bucket( key ).insert( std::forward<K>( key ), std::forward<V>( val ));
if ( bRet )
++m_ItemCounter;
return bRet;
- <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.
- User-defined functor \p func should guarantee that during changing item's value no any other changes
- could be made on this map's item by concurrent threads.
- The user-defined functor can be passed by reference using \p std::ref
- and it is called only if inserting is successful.
+ The user-defined functor is called only if inserting is successful.
- The key_type should be constructible from value of type \p K.
+ The \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;
This can be useful if complete initialization of object of \p mapped_type is heavyweight and
it is preferable that the initialization should be completed only if inserting is successful.
+
+ @warning For \ref cds_nonintrusive_MichaelKVList_gc "MichaelKVList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_nonintrusive_LazyKVList_gc "LazyKVList" provides exclusive access to inserted item and does not require any node-level
+ synchronization.
*/
template <typename K, typename Func>
- bool insert_key( const K& key, Func func )
+ bool insert_with( K&& key, Func func )
{
- const bool bRet = bucket( key ).insert_key( key, func );
+ const bool bRet = bucket( key ).insert_with( std::forward<K>( key ), func );
if ( bRet )
++m_ItemCounter;
return bRet;
}
-
- /// Ensures that the \p key exists in the map
+ /// Updates data by \p key
/**
- The operation performs inserting or changing data with lock-free manner.
+ 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
- is inserted into the map (note that in this case the \p key_type should be
- constructible from type \p K).
- Otherwise, the functor \p func is called with item found.
- The functor \p Func may be a function with signature:
- \code
- void func( bool bNew, value_type& item );
- \endcode
- or a functor:
+ will be inserted into the map iff \p bAllowInsert 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, the functor \p func is called with item found.
+
+ The functor \p func signature depends on \p OrderedList:
+
+ <b>for \p MichaelKVList, \p LazyKVList</b>
\code
struct my_functor {
void operator()( bool bNew, value_type& item );
};
\endcode
-
with arguments:
- \p bNew - \p true if the item has been inserted, \p false otherwise
- - \p item - item of the list
+ - \p item - the item found or inserted
- The functor may change any fields of the \p item.second that is \p mapped_type;
- however, \p func must guarantee that during changing no any other modifications
- could be made on this item by concurrent threads.
+ The functor may change any fields of the \p item.second that is \p mapped_type.
+
+ <b>for \p IterableKVList</b>
+ \code
+ void func( value_type& val, value_type * old );
+ \endcode
+ where
+ - \p val - a new data constructed from \p key
+ - \p old - old value that will be retired. If new item has been inserted then \p old is \p nullptr.
- You may pass \p func argument by reference using \p std::ref
+ The functor may change non-key fields of \p val; 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 true if operation is successfull,
+ @return <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successful,
\p second is true if new item has been added or \p false if the item with \p key
- already is in the list.
+ already exists.
+
+ @warning For \ref cds_nonintrusive_MichaelKVList_gc "MichaelKVList" and \ref cds_nonintrusive_IterableKVList_gc "IterableKVList"
+ as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_nonintrusive_LazyKVList_gc "LazyKVList" provides exclusive access to inserted item and does not require any node-level
+ synchronization.
*/
+ template <typename K, typename Func >
+ std::pair<bool, bool> update( K&& key, Func func, bool bAllowInsert = true )
+ {
+ std::pair<bool, bool> bRet = bucket( key ).update( std::forward<K>( key ), func, bAllowInsert );
+ if ( bRet.first && bRet.second )
+ ++m_ItemCounter;
+ return bRet;
+ }
+ //@cond
template <typename K, typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
std::pair<bool, bool> ensure( K const& key, Func func )
{
- std::pair<bool, bool> bRet = bucket( key ).ensure( key, func );
+ std::pair<bool, bool> bRet = bucket( key ).update( key, func, true );
if ( bRet.first && bRet.second )
++m_ItemCounter;
return bRet;
}
+ //@endcond
+
+ /// Inserts or updates the node (only for \p IterableKVList)
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If \p key is not found in the map, then \p key is inserted iff \p bAllowInsert is \p true.
+ Otherwise, the current element is changed to \p val, the old element will be retired later.
+
+ Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
+ \p second is \p true if \p val has been added or \p false if the item with that key
+ already in the map.
+ */
+ template <typename Q, typename V>
+#ifdef CDS_DOXYGEN_INVOKED
+ std::pair<bool, bool>
+#else
+ typename std::enable_if<
+ std::is_same< Q, Q>::value && is_iterable_list< ordered_list >::value,
+ std::pair<bool, bool>
+ >::type
+#endif
+ upsert( Q&& key, V&& val, bool bAllowInsert = true )
+ {
+ std::pair<bool, bool> bRet = bucket( val ).upsert( std::forward<Q>( key ), std::forward<V>( val ), bAllowInsert );
+ if ( bRet.second )
+ ++m_ItemCounter;
+ return bRet;
+ }
- /// For key \p key inserts data of type \p mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
+ /// For key \p key inserts data of type \p mapped_type created from \p args
/**
\p key_type should be constructible from type \p K
void operator()(value_type& item) { ... }
};
\endcode
- The functor may be passed by reference using <tt>boost:ref</tt>
Return \p true if key is found and deleted, \p false otherwise
*/
return bRet;
}
+ /// Deletes the item pointed by iterator \p iter (only for \p IterableList based map)
+ /**
+ Returns \p true if the operation is successful, \p false otherwise.
+ The function can return \p false if the node the iterator points to has already been deleted
+ by other thread.
+
+ The function does not invalidate the iterator, it remains valid and can be used for further traversing.
+
+ @note \p %erase_at() is supported only for \p %MichaelHashMap based on \p IterableList.
+ */
+#ifdef CDS_DOXYGEN_INVOKED
+ bool erase_at( iterator const& iter )
+#else
+ template <typename Iterator>
+ typename std::enable_if< std::is_same<Iterator, iterator>::value && is_iterable_list< ordered_list >::value, bool >::type
+ erase_at( Iterator const& iter )
+#endif
+ {
+ assert( iter != end());
+ assert( iter.bucket() != nullptr );
+
+ if ( iter.bucket()->erase_at( iter.underlying_iterator())) {
+ --m_ItemCounter;
+ return true;
+ }
+ return false;
+ }
+
/// Extracts the item with specified \p key
/** \anchor cds_nonintrusive_MichaelHashMap_hp_extract
The function searches an item with key equal to \p key,
- unlinks it from the set, and returns it in \p dest parameter.
- If the item with key equal to \p key is not found the function returns \p false.
+ unlinks it from the map, and returns it as \p guarded_ptr.
+ If \p key is not found the function returns an empty guarded pointer.
Note the compare functor should accept a parameter of type \p K that may be not the same as \p key_type.
- The extracted item is freed automatically when returned \ref guarded_ptr object will be destroyed or released.
+ The extracted item is freed automatically when returned \p guarded_ptr object will be destroyed or released.
@note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
Usage:
michael_map theMap;
// ...
{
- michael_map::guarded_ptr gp;
- theMap.extract( gp, 5 );
- // Deal with gp
- // ...
-
+ michael_map::guarded_ptr gp( theMap.extract( 5 ));
+ if ( gp ) {
+ // Deal with gp
+ // ...
+ }
// Destructor of gp releases internal HP guard
}
\endcode
*/
template <typename K>
- bool extract( guarded_ptr& dest, K const& key )
+ guarded_ptr extract( K const& key )
{
- const bool bRet = bucket( key ).extract( dest, key );
- if ( bRet )
+ guarded_ptr gp( bucket( key ).extract( key ));
+ if ( gp )
--m_ItemCounter;
- return bRet;
+ return gp;
}
/// Extracts the item using compare functor \p pred
/**
- The function is an analog of \ref cds_nonintrusive_MichaelHashMap_hp_extract "extract(guarded_ptr&, K const&)"
+ The function is an analog of \ref cds_nonintrusive_MichaelHashMap_hp_extract "extract(K const&)"
but \p pred predicate is used for key comparing.
- \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
+ \p Less functor has the semantics like \p std::less but should take arguments of type \p key_type and \p K
in any order.
\p pred must imply the same element order as the comparator used for building the map.
*/
template <typename K, typename Less>
- bool extract_with( guarded_ptr& dest, K const& key, Less pred )
+ guarded_ptr extract_with( K const& key, Less pred )
{
- const bool bRet = bucket( key ).extract_with( dest, key, pred );
- if ( bRet )
+ guarded_ptr gp( bucket( key ).extract_with( key, pred ));
+ if ( gp )
--m_ItemCounter;
- return bRet;
+ return gp;
}
/// Finds the key \p key
\endcode
where \p item is the item found.
- You may pass \p f argument by reference using \p std::ref.
-
The functor may change \p item.second. Note that the functor is only guarantee
that \p item cannot be disposed during functor is executing.
The functor does not serialize simultaneous access to the map's \p item. If such access is
return bucket( key ).find( key, f );
}
+ /// Finds \p key and returns iterator pointed to the item found (only for \p IterableList)
+ /**
+ If \p key is not found the function returns \p end().
+
+ @note This function is supported only for map based on \p IterableList
+ */
+ template <typename K>
+#ifdef CDS_DOXYGEN_INVOKED
+ iterator
+#else
+ typename std::enable_if< std::is_same<K,K>::value && is_iterable_list< ordered_list >::value, iterator >::type
+#endif
+ find( K const& key )
+ {
+ auto& b = bucket( key );
+ auto it = b.find( key );
+ if ( it == b.end())
+ return end();
+ return iterator( it, &b, bucket_end());
+ }
+
+
/// Finds the key \p val using \p pred predicate for searching
/**
The function is an analog of \ref cds_nonintrusive_MichaelMap_find_cfunc "find(K const&, Func)"
return bucket( key ).find_with( key, pred, f );
}
- /// Finds the key \p key
- /** \anchor cds_nonintrusive_MichaelMap_find_val
+ /// Finds \p key using \p pred predicate and returns iterator pointed to the item found (only for \p IterableList)
+ /**
+ The function is an analog of \p find(K&) 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.
+
+ If \p key is not found the function returns \p end().
+
+ @note This function is supported only for map based on \p IterableList
+ */
+ template <typename K, typename Less>
+#ifdef CDS_DOXYGEN_INVOKED
+ iterator
+#else
+ typename std::enable_if< std::is_same<K, K>::value && is_iterable_list< ordered_list >::value, iterator >::type
+#endif
+ find_with( K const& key, Less pred )
+ {
+ auto& b = bucket( key );
+ auto it = b.find_with( key, pred );
+ if ( it == b.end())
+ return end();
+ return iterator( it, &b, bucket_end());
+ }
+
+ /// Checks whether the map contains \p key
+ /**
The function searches the item with key equal to \p key
and returns \p true if it is found, and \p false otherwise.
*/
template <typename K>
- bool find( K const& key )
+ bool contains( K const& key )
{
- return bucket( key ).find( key );
+ return bucket( key ).contains( key );
}
- /// 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_find_val "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.
*/
template <typename K, typename Less>
- bool find_with( K const& key, Less pred )
+ bool contains( K const& key, Less pred )
{
- return bucket( key ).find_with( key, pred );
+ return bucket( key ).contains( key, pred );
}
/// Finds \p key and return the item found
/** \anchor cds_nonintrusive_MichaelHashMap_hp_get
The function searches the item with key equal to \p key
- and assigns the item found to guarded pointer \p ptr.
- The function returns \p true if \p key is found, and \p false otherwise.
- If \p key is not found the \p ptr parameter is not changed.
+ and returns the guarded pointer to the item found.
+ If \p key is not found the function returns an empty guarded pointer,
@note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
michael_map theMap;
// ...
{
- michael_map::guarded_ptr gp;
- if ( theMap.get( gp, 5 )) {
+ michael_map::guarded_ptr gp( theMap.get( 5 ));
+ if ( gp ) {
// Deal with gp
//...
}
should accept a parameter of type \p K that can be not the same as \p key_type.
*/
template <typename K>
- bool get( guarded_ptr& ptr, K const& key )
+ guarded_ptr get( K const& key )
{
- return bucket( key ).get( ptr, key );
+ return bucket( key ).get( key );
}
/// Finds \p key and return the item found
/**
- The function is an analog of \ref cds_nonintrusive_MichaelHashMap_hp_get "get( guarded_ptr& ptr, K const&)"
+ The function is an analog of \ref cds_nonintrusive_MichaelHashMap_hp_get "get( K const&)"
but \p pred is used for comparing the keys.
- \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
+ \p Less functor has the semantics like \p std::less but should take arguments of type \p key_type and \p K
in any order.
\p pred must imply the same element order as the comparator used for building the map.
*/
template <typename K, typename Less>
- bool get_with( guarded_ptr& ptr, K const& key, Less pred )
+ guarded_ptr get_with( K const& key, Less pred )
{
- return bucket( key ).get_with( ptr, key, pred );
+ return bucket( key ).get_with( key, pred );
}
- /// Clears the map (non-atomic)
- /**
- The function erases all items from the map.
-
- The function is not atomic. It cleans up each bucket and then resets the item counter to zero.
- If there are a thread that performs insertion while \p clear is working the result is undefined in general case:
- <tt> empty() </tt> may return \p true but the map may contain item(s).
- Therefore, \p clear may be used only for debugging purposes.
- */
+ /// Clears the map (not atomic)
void clear()
{
for ( size_t i = 0; i < bucket_count(); ++i )
/// 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 is an important part of the 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 the size of hash table
/**
- Since MichaelHashMap cannot dynamically extend the hash table size,
+ Since \p %MichaelHashMap cannot dynamically extend the hash table size,
the value returned is an constant depending on object initialization parameters;
- see MichaelHashMap::MichaelHashMap for explanation.
+ see \p MichaelHashMap::MichaelHashMap for explanation.
*/
size_t bucket_count() const
{
return m_nHashBitmask + 1;
}
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
+ protected:
+ //@cond
+ /// Calculates hash value of \p key
+ template <typename Q>
+ size_t hash_value( Q const& key ) const
+ {
+ return m_HashFunctor( key ) & m_nHashBitmask;
+ }
+
+ /// Returns the bucket (ordered list) for \p key
+ template <typename Q>
+ internal_bucket_type& bucket( Q const& key )
+ {
+ return m_Buckets[hash_value( key )];
+ }
+ //@endcond
+
+ private:
+ //@cond
+ internal_bucket_type* bucket_begin() const
+ {
+ return m_Buckets;
+ }
+
+ internal_bucket_type* bucket_end() const
+ {
+ return m_Buckets + bucket_count();
+ }
+
+ const_iterator get_const_begin() const
+ {
+ return const_iterator( bucket_begin()->cbegin(), bucket_begin(), bucket_end());
+ }
+ const_iterator get_const_end() const
+ {
+ return const_iterator( (bucket_end() - 1)->cend(), bucket_end() - 1, bucket_end());
+ }
+
+ 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
-#endif // ifndef __CDS_CONTAINER_MICHAEL_MAP_H
+#endif // ifndef CDSLIB_CONTAINER_MICHAEL_MAP_H
projects / libcds.git / blobdiff