Michael's hash set. More...

#include <cds/intrusive/michael_set.h>

Public Types
typedef GC	gc
	Garbage collector.

typedef OrderedList	ordered_list
	type of ordered list used as a bucket implementation

typedef Traits	traits
	Set traits.

typedef ordered_list::value_type	value_type
	type of value to be stored in the set

typedef ordered_list::key_comparator	key_comparator
	key comparing functor

typedef ordered_list::disposer	disposer
	Node disposer functor.

typedef ordered_list::stat	stat
	Internal statistics.

typedef cds::opt::v::hash_selector< typename traits::hash >::type	hash
	Hash functor for `value_type` and all its derivatives that you use.

typedef traits::item_counter	item_counter
	Item counter type.

typedef traits::allocator	allocator
	Bucket table allocator.

typedef ordered_list::guarded_ptr	guarded_ptr
	Guarded pointer.

Public Member Functions
	MichaelHashSet (size_t nMaxItemCount, size_t nLoadFactor)
	Initializes hash set. More...

	~MichaelHashSet ()
	Clears hash set object and destroys it.

bool	insert (value_type &val)
	Inserts new node. More...

template<typename Func >
bool	insert (value_type &val, Func f)
	Inserts new node. More...

template<typename Func >
std::pair< bool, bool >	update (value_type &val, Func func, bool bAllowInsert=true)
	Updates the element. More...

std::pair< bool, bool >	upsert (value_type &val, bool bAllowInsert=true)
	Inserts or updates the node (only for `IterableList`) More...

bool	unlink (value_type &val)
	Unlinks the item `val` from the set. More...

template<typename Q >
bool	erase (Q const &key)
	Deletes the item from the set. More...

template<typename Q , typename Less >
bool	erase_with (Q const &key, Less pred)
	Deletes the item from the set using `pred` predicate for searching. More...

template<typename Q , typename Func >
bool	erase (Q const &key, Func f)
	Deletes the item from the set. More...

template<typename Q , typename Less , typename Func >
bool	erase_with (Q const &key, Less pred, Func f)
	Deletes the item from the set using `pred` predicate for searching. More...

bool	erase_at (iterator const &iter)
	Deletes the item pointed by iterator `iter` (only for `IterableList` based set) More...

template<typename Q >
guarded_ptr	extract (Q const &key)
	Extracts the item with specified `key`. More...

template<typename Q , typename Less >
guarded_ptr	extract_with (Q const &key, Less pred)
	Extracts the item using compare functor `pred`. More...

template<typename Q , typename Func >
bool	find (Q &key, Func f)
	Finds the key `key`. More...

template<typename Q >
iterator	find (Q &key)
	Finds `key` and returns iterator pointed to the item found (only for `IterableList`) More...

template<typename Q , typename Less , typename Func >
bool	find_with (Q &key, Less pred, Func f)
	Finds the key `key` using `pred` predicate for searching. More...

template<typename Q , typename Less >
iterator	find_with (Q &key, Less pred)
	Finds `key` using `pred` predicate and returns iterator pointed to the item found (only for `IterableList`) More...

template<typename Q >
bool	contains (Q const &key)
	Checks whether the set contains `key`. More...

template<typename Q , typename Less >
bool	contains (Q const &key, Less pred)
	Checks whether the set contains `key` using `pred` predicate for searching. More...

template<typename Q >
guarded_ptr	get (Q const &key)
	Finds the key `key` and return the item found. More...

template<typename Q , typename Less >
guarded_ptr	get_with (Q const &key, Less pred)
	Finds the key `key` and return the item found. More...

void	clear ()
	Clears the set (non-atomic) More...

bool	empty () const
	Checks if the set is empty. More...

size_t	size () const
	Returns item count in the set. More...

stat const &	statistics () const
	Returns const reference to internal statistics.

size_t	bucket_count () const
	Returns the size of hash table. More...

Static Public Attributes
static constexpr const size_t	c_nHazardPtrCount = ordered_list::c_nHazardPtrCount
	Count of hazard pointer required for the algorithm.

Forward iterators
typedef michael_set::details::iterator< internal_bucket_type, false >	iterator
	Forward iterator. More...

typedef michael_set::details::iterator< internal_bucket_type, true >	const_iterator
	Const forward iterator. More...

iterator	begin ()
	Returns a forward iterator addressing the first element in a set. More...

iterator	end ()
	Returns an iterator that addresses the location succeeding the last element in a set. More...

const_iterator	begin () const
	Returns a forward const iterator addressing the first element in a set.

const_iterator	cbegin () const
	Returns a forward const iterator addressing the first element in a set.

const_iterator	end () const
	Returns an const iterator that addresses the location succeeding the last element in a set.

const_iterator	cend () const
	Returns an const iterator that addresses the location succeeding the last element in a set.

Detailed Description

template<class GC, class OrderedList, class Traits = michael_set::traits>
class cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >

Michael's hash set.

Source:

[2002] Maged Michael "High performance dynamic lock-free hash tables and list-based sets"

Michael's hash table algorithm is based on lock-free ordered list and it is very simple. The main structure is an array T of size M. Each element in T is basically a pointer to a hash bucket, implemented as a singly linked list. The array of buckets cannot be dynamically expanded. However, each bucket may contain unbounded number of items.

Template parameters are:

GC - Garbage collector used. Note the GC must be the same as the GC used for OrderedList
OrderedList - ordered list implementation used as bucket for hash set, possible implementations: MichaelList, LazyList, IterableList. The intrusive ordered list implementation specifies the type T stored in the hash-set, the reclamation schema GC used by hash-set, the comparison functor for the type T and other features specific for the ordered list.
Traits - type traits. See michael_set::traits for explanation. Instead of defining Traits struct you can use option-based syntax with michael_set::make_traits metafunction.

There are several specializations of MichaelHashSet for each GC. You should include:

<cds/intrusive/michael_set_rcu.h> for RCU type
<cds/intrusive/michael_set_nogc.h> for cds_intrusive_MichaelHashSet_nogc for append-only set
<cds/intrusive/michael_set.h> for gc::HP, gc::DHP

Hash functor

Some member functions of Michael's hash set accept the key parameter of type Q which differs from value_type. It is expected that type Q contains full key of value_type, and for equal keys of type Q and value_type the hash values of these keys must be equal. The hash functor Traits::hash should accept parameters of both type:

// Our node type
struct Foo {
    std::string key_; // key field
    // ... other fields
};
// Hash functor
struct fooHash {
    size_t operator()( const std::string& s ) const
    {
        return std::hash( s );
    }
    size_t operator()( const Foo& f ) const
    {
        return (*this)( f.key_ );
    }
};

How to use

First, you should define ordered list type to use in your hash set:

// For gc::HP-based MichaelList implementation
#include <cds/intrusive/michael_list_hp.h>
// cds::intrusive::MichaelHashSet declaration
#include <cds/intrusive/michael_set.h>
// Type of hash-set items
struct Foo: public cds::intrusive::michael_list::node< cds::gc::HP >
{
    std::string     key_    ;   // key field
    unsigned        val_    ;   // value field
    // ...  other value fields
};
// Declare comparator for the item
struct FooCmp
{
    int operator()( const Foo& f1, const Foo& f2 ) const
    {
        return f1.key_.compare( f2.key_ );
    }
};
// Declare bucket type for Michael's hash set
// The bucket type is any ordered list type like MichaelList, LazyList
typedef cds::intrusive::MichaelList< cds::gc::HP, Foo,
    typename cds::intrusive::michael_list::make_traits<
        // hook option
        cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP > > >
        // item comparator option
        ,cds::opt::compare< FooCmp >
    >::type
>  Foo_bucket;

Second, you should declare Michael's hash set container:

// Declare hash functor
// Note, the hash functor accepts parameter type Foo and std::string
struct FooHash {
    size_t operator()( const Foo& f ) const
    {
        return cds::opt::v::hash<std::string>()( f.key_ );
    }
    size_t operator()( const std::string& f ) const
    {
        return cds::opt::v::hash<std::string>()( f );
    }
};
// Michael's set typedef
typedef cds::intrusive::MichaelHashSet<
    cds::gc::HP
    ,Foo_bucket
    ,typename cds::intrusive::michael_set::make_traits<
        cds::opt::hash< FooHash >
    >::type
> Foo_set;

Now, you can use Foo_set in your application.

Like other intrusive containers, you may build several containers on single item structure:

#include <cds/intrusive/michael_list_hp.h>
#include <cds/intrusive/michael_list_dhp.h>
#include <cds/intrusive/michael_set.h>
struct tag_key1_idx;
struct tag_key2_idx;
// Your two-key data
// The first key is maintained by gc::HP, second key is maintained by gc::DHP garbage collectors
// (I don't know what is needed for, but it is correct)
struct Foo
    : public cds::intrusive::michael_list::node< cds::gc::HP, tag_key1_idx >
    , public cds::intrusive::michael_list::node< cds::gc::DHP, tag_key2_idx >
{
    std::string     key1_   ;   // first key field
    unsigned int    key2_   ;   // second key field
    // ... value fields and fields for controlling item's lifetime
};
// Declare comparators for the item
struct Key1Cmp
{
    int operator()( const Foo& f1, const Foo& f2 ) const { return f1.key1_.compare( f2.key1_ ) ; }
};
struct Key2Less
{
    bool operator()( const Foo& f1, const Foo& f2 ) const { return f1.key2_ < f2.key1_ ; }
};
// Declare bucket type for Michael's hash set indexed by key1_ field and maintained by gc::HP
typedef cds::intrusive::MichaelList< cds::gc::HP, Foo,
    typename cds::intrusive::michael_list::make_traits<
        // hook option
        cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP >, tag_key1_idx > >
        // item comparator option
        ,cds::opt::compare< Key1Cmp >
    >::type
>  Key1_bucket;
// Declare bucket type for Michael's hash set indexed by key2_ field and maintained by gc::DHP
typedef cds::intrusive::MichaelList< cds::gc::DHP, Foo,
    typename cds::intrusive::michael_list::make_traits<
        // hook option
        cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::DHP >, tag_key2_idx > >
        // item comparator option
        ,cds::opt::less< Key2Less >
    >::type
>  Key2_bucket;
// Declare hash functor
struct Key1Hash {
    size_t operator()( const Foo& f ) const { return cds::opt::v::hash<std::string>()( f.key1_ ) ; }
    size_t operator()( const std::string& s ) const { return cds::opt::v::hash<std::string>()( s ) ; }
};
inline size_t Key2Hash( const Foo& f ) { return (size_t) f.key2_  ; }
// Michael's set indexed by key1_ field
typedef cds::intrusive::MichaelHashSet<
    cds::gc::HP
    ,Key1_bucket
    ,typename cds::intrusive::michael_set::make_traits<
        cds::opt::hash< Key1Hash >
    >::type
> key1_set;
// Michael's set indexed by key2_ field
typedef cds::intrusive::MichaelHashSet<
    cds::gc::DHP
    ,Key2_bucket
    ,typename cds::intrusive::michael_set::make_traits<
        cds::opt::hash< Key2Hash >
    >::type
> key2_set;

Member Typedef Documentation

◆ const_iterator

template<class GC , class OrderedList , class Traits = michael_set::traits>

typedef michael_set::details::iterator< internal_bucket_type, true > cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::const_iterator

Const forward iterator.

For iterator's features and requirements see iterator

◆ iterator

template<class GC , class OrderedList , class Traits = michael_set::traits>

typedef michael_set::details::iterator< internal_bucket_type, false > cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::iterator

Forward iterator.

The forward iterator for Michael's set is based on OrderedList forward iterator and has some features:

it has no post-increment operator
it iterates items in unordered fashion
The iterator cannot be moved across thread boundary because it may contain GC's guard that is thread-private GC data.

Iterator thread safety depends on type of OrderedList:

for MichaelList and LazyList: 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 set. 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 IterableList: iterator is thread-safe. You may use it freely in concurrent environment.

Constructor & Destructor Documentation

◆ MichaelHashSet()

template<class GC , class OrderedList , class Traits = michael_set::traits>

cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::MichaelHashSet	(	size_t	nMaxItemCount,
		size_t	nLoadFactor
	)

inline

Initializes hash set.

The Michael's hash set is an unbounded container, but its hash table is non-expandable. At construction time you should pass estimated maximum item count and a load factor. The load factor is average size of one bucket - a small number between 1 and 10. The bucket is an ordered single-linked list, searching in the bucket has linear complexity O(nLoadFactor). The constructor defines hash table size as rounding nMaxItemCount / nLoadFactor up to nearest power of two.

Parameters

nMaxItemCount	estimation of max item count in the hash set
nLoadFactor	load factor: estimation of max number of items in the bucket. Small integer up to 10.

Member Function Documentation

◆ begin()

template<class GC , class OrderedList , class Traits = michael_set::traits>

iterator cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::begin ( )

inline

Returns a forward iterator addressing the first element in a set.

For empty set

begin() == end()

◆ bucket_count()

template<class GC , class OrderedList , class Traits = michael_set::traits>

size_t cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::bucket_count ( ) const

inline

Returns the size of hash table.

Since MichaelHashSet cannot dynamically extend the hash table size, the value returned is an constant depending on object initialization parameters, see MichaelHashSet::MichaelHashSet.

◆ clear()

template<class GC , class OrderedList , class Traits = michael_set::traits>

void cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::clear ( )

inline

Clears the set (non-atomic)

The function unlink all items from the set. 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 clear() is working the result is undefined in general case: empty() may return true but the set may contain item(s). Therefore, clear() may be used only for debugging purposes.

For each item the disposer is called after unlinking.

◆ contains() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::contains ( Q const & key )

inline

Checks whether the set contains key.

The function searches the item with key equal to key and returns true if the key is found, and false otherwise.

Note the hash functor specified for class Traits template parameter should accept a parameter of type Q that can be not the same as value_type.

◆ contains() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::contains	(	Q const &	key,
		Less	pred
	)

inline

Checks whether the set contains key using pred predicate for searching.

The function is an analog of contains( key ) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the set.

◆ empty()

template<class GC , class OrderedList , class Traits = michael_set::traits>

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::empty ( ) const

inline

Checks if the set is empty.

Warning: If you use atomicity::empty_item_counter in traits::item_counter, the function always returns true.

◆ end()

template<class GC , class OrderedList , class Traits = michael_set::traits>

iterator cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::end ( )

inline

Returns an iterator that addresses the location succeeding the last element in a set.

Do not use the value returned by end function to access any item. The returned value can be used only to control reaching the end of the set. For empty set

begin() == end()

◆ erase() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::erase ( Q const & key )

inline

Deletes the item from the set.

The function searches an item with key equal to key in the set, unlinks it, and returns true. If the item with key equal to key is not found the function return false.

Note the hash functor should accept a parameter of type Q that can be not the same as value_type.

◆ erase() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Func >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::erase	(	Q const &	key,
		Func	f
	)

inline

Deletes the item from the set.

The function searches an item with key equal to key in the set, call f functor with item found, and unlinks it from the set. The disposer specified in OrderedList class template parameter is called by garbage collector GC asynchronously.

The Func interface is

struct functor {
    void operator()( value_type const& item );
};

If the item with key equal to key is not found the function return false.

Note the hash functor should accept a parameter of type Q that can be not the same as value_type.

◆ erase_at()

template<class GC , class OrderedList , class Traits = michael_set::traits>

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::erase_at ( iterator const & iter )

inline

Deletes the item pointed by iterator iter (only for IterableList based set)

Returns true if the operation is successful, false otherwise. The function can return 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: erase_at() is supported only for MichaelHashSet based on IterableList.

◆ erase_with() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::erase_with	(	Q const &	key,
		Less	pred
	)

inline

Deletes the item from the set using pred predicate for searching.

The function is an analog of erase(Q const&) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

◆ erase_with() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less , typename Func >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::erase_with	(	Q const &	key,
		Less	pred,
		Func	f
	)

inline

Deletes the item from the set using pred predicate for searching.

The function is an analog of erase(Q const&, Func) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

◆ extract()

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q >

guarded_ptr cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::extract ( Q const & key )

inline

Extracts the item with specified key.

The function searches an item with key equal to key, unlinks it from the set, and returns an guarded pointer to the item extracted. If key is not found the function returns an empty guarded pointer.

Note the compare functor should accept a parameter of type Q that may be not the same as value_type.

The disposer specified in OrderedList class' template parameter is called automatically by garbage collector GC when returned guarded_ptr object will be destroyed or released.

Note: Each guarded_ptr object uses the GC's guard that can be limited resource.

Usage:

typedef cds::intrusive::MichaelHashSet< your_template_args > michael_set;
michael_set theSet;
// ...
{
    michael_set::guarded_ptr gp( theSet.extract( 5 ));
    if ( gp ) {
        // Deal with gp
        // ...
    }
    // Destructor of gp releases internal HP guard
}

◆ extract_with()

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less >

guarded_ptr cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::extract_with	(	Q const &	key,
		Less	pred
	)

inline

Extracts the item using compare functor pred.

The function is an analog of extract(Q const&) but pred predicate is used for key comparing.

Less functor has the semantics like std::less but should take arguments of type value_type and Q in any order. pred must imply the same element order as the comparator used for building the list.

◆ find() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Func >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::find	(	Q &	key,
		Func	f
	)

inline

Finds the key key.

The function searches the item with key equal to key and calls the functor f for item found. The interface of Func functor is:

struct functor {
    void operator()( value_type& item, Q& key );
};

where item is the item found, key is the find function argument.

The functor may change non-key fields of item. Note that the functor is only guarantee that item cannot be disposed during functor is executing. The functor does not serialize simultaneous access to the set item. If such access is possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.

The key argument is non-const since it can be used as f functor destination i.e., the functor may modify both arguments.

Note the hash functor specified for class Traits template parameter should accept a parameter of type Q that can be not the same as value_type.

The function returns true if key is found, false otherwise.

◆ find() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q >

iterator cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::find ( Q & key )

inline

Finds key and returns iterator pointed to the item found (only for IterableList)

If key is not found the function returns end().

Note: This function is supported only for the set based on IterableList

◆ find_with() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less , typename Func >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::find_with	(	Q &	key,
		Less	pred,
		Func	f
	)

inline

Finds the key key using pred predicate for searching.

The function is an analog of find(Q&, Func) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

◆ find_with() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less >

iterator cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::find_with	(	Q &	key,
		Less	pred
	)

inline

Finds key using pred predicate and returns iterator pointed to the item found (only for IterableList)

The function is an analog of find(Q&) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

If key is not found the function returns end().

Note: This function is supported only for the set based on IterableList

◆ get()

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q >

guarded_ptr cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::get ( Q const & key )

inline

Finds the key key and return the item found.

The function searches the item with key equal to key and returns the guarded pointer to the item found. If key is not found the function returns an empty guarded_ptr.

Note: Each guarded_ptr object uses one GC's guard which can be limited resource.

Usage:

typedef cds::intrusive::MichaelHashSet< your_template_params >  michael_set;
michael_set theSet;
// ...
{
    michael_set::guarded_ptr gp( theSet.get( 5 ));
    if ( theSet.get( 5 )) {
        // Deal with gp
        //...
    }
    // Destructor of guarded_ptr releases internal HP guard
}

Note the compare functor specified for OrderedList template parameter should accept a parameter of type Q that can be not the same as value_type.

◆ get_with()

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Q , typename Less >

guarded_ptr cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::get_with	(	Q const &	key,
		Less	pred
	)

inline

Finds the key key and return the item found.

The function is an analog of get( Q const&) but pred is used for comparing the keys.

Less functor has the semantics like std::less but should take arguments of type value_type and Q in any order. pred must imply the same element order as the comparator used for building the set.

◆ insert() [1/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::insert ( value_type & val )

inline

Inserts new node.

The function inserts val in the set if it does not contain an item with key equal to val.

Returns true if val is placed into the set, false otherwise.

◆ insert() [2/2]

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Func >

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::insert	(	value_type &	val,
		Func	f
	)

inline

Inserts new node.

This function is intended for derived non-intrusive containers.

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 f functor to initialize value-field of val.

The functor signature is:

void func( value_type& val );

where val is the item inserted.

The user-defined functor is called only if the inserting is success.

Warning: For MichaelList as the bucket see insert item troubleshooting. LazyList provides exclusive access to inserted item and does not require any node-level synchronization.

◆ size()

template<class GC , class OrderedList , class Traits = michael_set::traits>

size_t cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::size ( ) const

inline

Returns item count in the set.

If you use atomicity::empty_item_counter in traits::item_counter, the function always returns 0.

◆ unlink()

template<class GC , class OrderedList , class Traits = michael_set::traits>

bool cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::unlink ( value_type & val )

inline

Unlinks the item val from the set.

The function searches the item val in the set and unlink it if it is found and is equal to val.

The function returns true if success and false otherwise.

◆ update()

template<class GC , class OrderedList , class Traits = michael_set::traits>

template<typename Func >

std::pair<bool, bool> cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::update	(	value_type &	val,
		Func	func,
		bool	bAllowInsert = `true`
	)

inline

Updates the element.

The operation performs inserting or changing data with lock-free manner.

If the item val not found in the set, then val is inserted iff bAllowInsert is true. Otherwise, the functor func is called with item found.

The functor signature depends of the type of OrderedList:

for MichaelList, LazyList

struct functor {
    void operator()( bool bNew, value_type& item, value_type& val );
};

with arguments:

bNew - true if the item has been inserted, false otherwise
item - item of the set
val - argument val passed into the update() function If new item has been inserted (i.e. bNew is true) then item and val arguments refers to the same thing.

The functor may change non-key fields of the item.

Warning: For MichaelList as the bucket see insert item troubleshooting. LazyList provides exclusive access to inserted item and does not require any node-level synchronization.

for IterableList

void func( value_type& val, value_type * old );

where

val - argument val passed into the update() function
old - old value that will be retired. If new item has been inserted then old is nullptr.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if new item has been added or false if the item with key already is in the set.

◆ upsert()

template<class GC , class OrderedList , class Traits = michael_set::traits>

std::pair<bool, bool> cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >::upsert	(	value_type &	val,
		bool	bAllowInsert = `true`
	)

inline

Inserts or updates the node (only for IterableList)

The operation performs inserting or changing data with lock-free manner.

If the item val is not found in the set, then val is inserted iff bAllowInsert is true. Otherwise, the current element is changed to val, the old element will be retired later by call Traits::disposer.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if val has been added or false if the item with that key already in the set.

The documentation for this class was generated from the following file:

cds/intrusive/michael_set.h

Public Types

Public Member Functions

Static Public Attributes

Forward iterators

Detailed Description

template<class GC, class OrderedList, class Traits = michael_set::traits> class cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >

Member Typedef Documentation

◆ const_iterator

◆ iterator

Constructor & Destructor Documentation

◆ MichaelHashSet()

Member Function Documentation

◆ begin()

◆ bucket_count()

◆ clear()

◆ contains() [1/2]

◆ contains() [2/2]

◆ empty()

◆ end()

◆ erase() [1/2]

◆ erase() [2/2]

◆ erase_at()

◆ erase_with() [1/2]

◆ erase_with() [2/2]

◆ extract()

◆ extract_with()

◆ find() [1/2]

◆ find() [2/2]

◆ find_with() [1/2]

◆ find_with() [2/2]

◆ get()

◆ get_with()

◆ insert() [1/2]

◆ insert() [2/2]

◆ size()

◆ unlink()

◆ update()

◆ upsert()

template<class GC, class OrderedList, class Traits = michael_set::traits>
class cds::intrusive::MichaelHashSet< GC, OrderedList, Traits >