-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+
+ 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_INTRUSIVE_IMPL_ELLEN_BINTREE_H
#define CDSLIB_INTRUSIVE_IMPL_ELLEN_BINTREE_H
the priority value plus some uniformly distributed random value.
@note In the current implementation we do not use helping technique described in the original paper.
- In Hazard Pointer schema helping is too complicated and does not give any observable benefits.
+ In Hazard Pointer schema the helping is too complicated and does not give any observable benefits.
Instead of helping, when a thread encounters a concurrent operation it just spins waiting for
- the operation done. Such solution allows greatly simplify the implementation of tree.
+ the operation done. Such solution allows greatly simplify implementation of the tree.
- @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
+ @attention Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
@note Do not include <tt><cds/intrusive/impl/ellen_bintree.h></tt> header file explicitly.
typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
- //@cond
- typedef cds::intrusive::ellen_bintree::implementation_tag implementation_tag;
- //@endcond
-
protected:
//@cond
typedef ellen_bintree::base_node< gc > tree_node; ///< Base type of tree node
typedef typename traits::node_allocator node_allocator; ///< Allocator for internal node
typedef typename traits::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
+ static CDS_CONSTEXPR const size_t c_nHazardPtrCount = 9; ///< Count of hazard pointer required for the algorithm
+
protected:
//@cond
typedef ellen_bintree::details::compare< key_type, value_type, key_comparator, node_traits > node_compare;
Guard_Leaf,
Guard_updGrandParent,
Guard_updParent,
-
- // helping
- Guard_helpLeaf,
+ Guard_temporary,
// end of guard indices
guard_count
,bRightLeaf( false )
,bRightParent( false )
{}
-
- void clean_help_guards()
- {
- guards.clear( Guard_helpLeaf );
- }
};
//@endcond
return true;
}
- /// Ensures that the \p val exists in the tree
+ /// Updates the node
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val is not found in the tree, then \p val is inserted into the tree.
+ If the item \p val is not found in the set, then \p val is inserted into the set
+ iff \p bAllowInsert is \p true.
Otherwise, the functor \p func is called with item found.
- The functor signature is:
+ The functor \p func signature is:
\code
void func( bool bNew, value_type& item, value_type& val );
\endcode
with arguments:
- \p bNew - \p true if the item has been inserted, \p false otherwise
- - \p item - an item of the tree
- - \p val - the argument \p val passed to the \p ensure function
+ - \p item - item of the set
+ - \p val - argument \p val passed into the \p %update() function
If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
refer to the same thing.
that during changing no any other modifications could be made on this item by concurrent threads.
Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
+ i.e. the node has been inserted or updated,
\p second is \p true if new item has been added or \p false if the item with \p key
- already is in the tree.
+ already exists.
@warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
*/
template <typename Func>
- std::pair<bool, bool> ensure( value_type& val, Func func )
+ std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
{
typename gc::Guard guardInsert;
guardInsert.assign( &val );
}
if ( res.updGrandParent.bits() == update_desc::Clean && res.updParent.bits() == update_desc::Clean ) {
+ if ( !bAllowInsert )
+ return std::make_pair( false, false );
if ( !pNewInternal.get() )
pNewInternal.reset( alloc_internal_node() );
m_Stat.onEnsureNew();
return std::make_pair( true, true );
}
+ //@cond
+ template <typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( value_type& val, Func func )
+ {
+ return update( val, func, true );
+ }
+ //@endcond
/// Unlinks the item \p val from the tree
/**
return gp;
}
- /// Finds the key \p key
- /** @anchor cds_intrusive_EllenBinTree_find_val
+ /// Checks whether the set 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.
-
- Note the hash functor specified for class \p Traits template parameter
- should accept a parameter of type \p Q that can be not the same as \p value_type.
*/
template <typename Q>
- bool find( Q const& key ) const
+ bool contains( Q const& key ) const
{
search_result res;
if ( search( res, key, node_compare() )) {
m_Stat.onFindFailed();
return false;
}
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key ) const
+ {
+ return contains( key );
+ }
+ //@endcond
- /// Finds the key \p key with comparing functor \p pred
+ /// Checks whether the set contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_EllenBinTree_find_val "find(Q const&)"
- but \p pred is used for key compare.
- \p Less functor has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_less
- "Predicate requirements".
- \p pred must imply the same element order as the comparator used for building the tree.
- \p pred should accept arguments of type \p Q, \p key_type, \p value_type in any combination.
+ The function is similar to <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 set.
*/
template <typename Q, typename Less>
- bool find_with( Q const& key, Less pred ) const
+ bool contains( Q const& key, Less pred ) const
{
CDS_UNUSED( pred );
typedef ellen_bintree::details::compare<
m_Stat.onFindFailed();
return false;
}
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred ) const
+ {
+ return contains( key, pred );
+ }
+ //@endcond
/// Finds the key \p key
/** @anchor cds_intrusive_EllenBinTree_find_func
tree_node * protect_child_node( search_result& res, internal_node * pParent, bool bRight, update_ptr updParent ) const
{
- tree_node * p;
- tree_node * pn = bRight ? pParent->m_pRight.load( memory_model::memory_order_relaxed ) : pParent->m_pLeft.load( memory_model::memory_order_relaxed );
- do {
- p = pn;
- res.guards.assign( search_result::Guard_Leaf, static_cast<internal_node *>( p ));
- res.guards.assign( search_result::Guard_helpLeaf, node_traits::to_value_ptr( static_cast<leaf_node *>( p ) ));
- pn = bRight ? pParent->m_pRight.load( memory_model::memory_order_acquire ) : pParent->m_pLeft.load( memory_model::memory_order_acquire );
- } while ( p != pn );
+ retry:
+ tree_node * p = bRight
+ ? res.guards.protect( search_result::Guard_Leaf, pParent->m_pRight,
+ []( tree_node * p ) -> internal_node* { return static_cast<internal_node *>(p);})
+ : res.guards.protect( search_result::Guard_Leaf, pParent->m_pLeft,
+ []( tree_node * p ) -> internal_node* { return static_cast<internal_node *>(p);});
+
+ // If we use member hook, data node pointer != internal node pointer
+ // So, we need protect the child twice: as internal node and as data node
+ // and then analyze what kind of node we have
+ tree_node * pVal = bRight
+ ? res.guards.protect( search_result::Guard_temporary, pParent->m_pRight,
+ []( tree_node * p ) -> value_type* { return node_traits::to_value_ptr( static_cast<leaf_node *>(p));} )
+ : res.guards.protect( search_result::Guard_temporary, pParent->m_pLeft,
+ []( tree_node * p ) -> value_type* { return node_traits::to_value_ptr( static_cast<leaf_node *>(p));} );
// child node is guarded
// See whether pParent->m_pUpdate has not been changed
return nullptr;
}
- if ( p && p->is_leaf() )
- res.guards.copy( search_result::Guard_Leaf, search_result::Guard_helpLeaf );
- res.guards.clear( search_result::Guard_helpLeaf );
+ if ( p != pVal )
+ goto retry;
+
+ if ( p && p->is_leaf())
+ res.guards.assign( search_result::Guard_Leaf, node_traits::to_value_ptr( static_cast<leaf_node *>( p )));
+
+ res.guards.clear( search_result::Guard_temporary );
+
return p;
}
- update_ptr search_protect_update( search_result& res, atomics::atomic<update_ptr> const& src ) const
+ static update_ptr search_protect_update( search_result& res, atomics::atomic<update_ptr> const& src )
{
- update_ptr ret;
- update_ptr upd( src.load( memory_model::memory_order_relaxed ) );
- do {
- ret = upd;
- res.guards.assign( search_result::Guard_updParent, upd );
- } while ( ret != (upd = src.load( memory_model::memory_order_acquire )) );
- return ret;
+ return res.guards.protect( search_result::Guard_updParent, src, [](update_ptr p) -> update_desc* { return p.ptr(); });
}
template <typename KeyValue, typename Compare>
assert( res.pGrandParent != nullptr );
- return
- static_cast<internal_node *>(
- res.bRightParent
- ? res.pGrandParent->m_pRight.load(memory_model::memory_order_relaxed)
- : res.pGrandParent->m_pLeft.load(memory_model::memory_order_relaxed)
- ) == res.pParent
- &&
- static_cast<leaf_node *>(
- res.bRightLeaf
- ? res.pParent->m_pRight.load(memory_model::memory_order_relaxed)
- : res.pParent->m_pLeft.load(memory_model::memory_order_relaxed)
- ) == res.pLeaf;
+ return static_cast<internal_node *>(res.pGrandParent->get_child( res.bRightParent, memory_model::memory_order_relaxed )) == res.pParent
+ && static_cast<leaf_node *>( res.pParent->get_child( res.bRightLeaf, memory_model::memory_order_relaxed )) == res.pLeaf;
}
bool help_delete( update_desc * pOp )
}
}
- tree_node * protect_sibling( typename gc::Guard& guard, atomics::atomic<tree_node *>& sibling )
+ static tree_node * protect_sibling( typename gc::Guard& guard, atomics::atomic<tree_node *>& sibling )
{
- typename gc::Guard guardLeaf;
-
- tree_node * pSibling;
- tree_node * p = sibling.load( memory_model::memory_order_relaxed );
- do {
- pSibling = p;
- guard.assign( static_cast<internal_node *>(p) );
- guardLeaf.assign( node_traits::to_value_ptr( static_cast<leaf_node *>(p)));
- } while ( pSibling != ( p = sibling.load( memory_model::memory_order_acquire )) );
-
+ tree_node * pSibling = guard.protect( sibling, [](tree_node * p) -> internal_node* { return static_cast<internal_node *>(p); } );
if ( pSibling->is_leaf() )
- guard.copy( guardLeaf );
-
+ guard.assign( node_traits::to_value_ptr( static_cast<leaf_node *>( pSibling )));
return pSibling;
}
assert( res.pLeaf->is_leaf() );
// check search result
- if ( (res.bRightLeaf
- ? res.pParent->m_pRight.load( memory_model::memory_order_acquire )
- : res.pParent->m_pLeft.load( memory_model::memory_order_acquire )) == res.pLeaf ) {
+ if ( res.pParent->get_child( res.bRightLeaf, memory_model::memory_order_acquire ) == res.pLeaf ) {
leaf_node * pNewLeaf = node_traits::to_node_ptr( val );
int nCmp = node_compare()(val, *res.pLeaf);
}
else {
assert( !res.pLeaf->is_internal() );
- pNewInternal->infinite_key( 0 );
+ pNewInternal->infinite_key( 0 );
key_extractor()(pNewInternal->m_Key, val);
pNewInternal->m_pLeft.store( static_cast<tree_node *>(res.pLeaf), memory_model::memory_order_relaxed );
pNewInternal->m_pRight.store( static_cast<tree_node *>(pNewLeaf), memory_model::memory_order_release );
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