-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
-#ifndef __CDS_INTRUSIVE_IMPL_SKIP_LIST_H
-#define __CDS_INTRUSIVE_IMPL_SKIP_LIST_H
+ (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_SKIP_LIST_H
+#define CDSLIB_INTRUSIVE_IMPL_SKIP_LIST_H
#include <type_traits>
#include <memory>
#include <cds/intrusive/details/skip_list_base.h>
#include <cds/opt/compare.h>
#include <cds/details/binary_functor_wrapper.h>
-#include <cds/gc/guarded_ptr.h>
namespace cds { namespace intrusive {
typedef BackOff back_off;
typedef typename node_traits::node_type node_type;
typedef typename node_traits::value_type value_type;
- static bool const c_isConst = IsConst;
+ static CDS_CONSTEXPR bool const c_isConst = IsConst;
- typedef typename std::conditional< c_isConst, value_type const &, value_type &>::type value_ref;
+ typedef typename std::conditional< c_isConst, value_type const&, value_type&>::type value_ref;
protected:
typedef typename node_type::marked_ptr marked_ptr;
protected:
static value_type * gc_protect( marked_ptr p )
{
- return node_traits::to_value_ptr( p.ptr() );
+ return node_traits::to_value_ptr( p.ptr());
}
void next()
back_off bkoff;
for (;;) {
- if ( m_pNode->next( m_pNode->height() - 1 ).load( atomics::memory_order_acquire ).bits() ) {
+ if ( m_pNode->next( m_pNode->height() - 1 ).load( atomics::memory_order_acquire ).bits()) {
// Current node is marked as deleted. So, its next pointer can point to anything
// In this case we interrupt our iteration and returns end() iterator.
*this = iterator();
marked_ptr p = m_guard.protect( (*m_pNode)[0], gc_protect );
node_type * pp = p.ptr();
- if ( p.bits() ) {
+ if ( p.bits()) {
// p is marked as deleted. Spin waiting for physical removal
bkoff();
continue;
}
- else if ( pp && pp->next( pp->height() - 1 ).load( atomics::memory_order_relaxed ).bits() ) {
+ else if ( pp && pp->next( pp->height() - 1 ).load( atomics::memory_order_relaxed ).bits()) {
// p is marked as deleted. Spin waiting for physical removal
bkoff();
continue;
for (;;) {
marked_ptr p = m_guard.protect( refHead[0], gc_protect );
- if ( !p.ptr() ) {
+ if ( !p.ptr()) {
// empty skip-list
m_guard.clear();
break;
node_type * pp = p.ptr();
// Logically deleted node is marked from highest level
- if ( !pp->next( pp->height() - 1 ).load( atomics::memory_order_acquire ).bits() ) {
+ if ( !pp->next( pp->height() - 1 ).load( atomics::memory_order_acquire ).bits()) {
m_pNode = pp;
break;
}
iterator( iterator const& s)
: m_pNode( s.m_pNode )
{
- m_guard.assign( node_traits::to_value_ptr(m_pNode) );
+ m_guard.assign( node_traits::to_value_ptr(m_pNode));
}
value_type * operator ->() const
return *this;
}
- iterator& operator = (const iterator& src)
+ iterator& operator =(const iterator& src)
{
m_pNode = src.m_pNode;
m_guard.copy( src.m_guard );
The lock-free variant of skip-list is implemented according to book
- [2008] M.Herlihy, N.Shavit "The Art of Multiprocessor Programming",
chapter 14.4 "A Lock-Free Concurrent Skiplist".
- \note The algorithm described in this book cannot be directly adapted for C++ (roughly speaking,
- the algo contains a lot of bugs). The \b libcds implementation applies the approach discovered
- by M.Michael in his \ref cds_intrusive_MichaelList_hp "lock-free linked list".
<b>Template arguments</b>:
- - \p GC - Garbage collector used. Note the \p GC must be the same as the GC used for item type \p T (see skip_list::node).
- - \p T - type to be stored in the list. The type must be based on skip_list::node (for skip_list::base_hook)
- or it must have a member of type skip_list::node (for skip_list::member_hook).
- - \p Traits - type traits. See skip_list::type_traits for explanation.
-
- It is possible to declare option-based list with cds::intrusive::skip_list::make_traits metafunction istead of \p Traits template
- argument.
- Template argument list \p Options of cds::intrusive::skip_list::make_traits metafunction are:
- - opt::hook - hook used. Possible values are: skip_list::base_hook, skip_list::member_hook, skip_list::traits_hook.
- If the option is not specified, <tt>skip_list::base_hook<></tt> and gc::HP is used.
- - opt::compare - key comparison functor. No default functor is provided.
- If the option is not specified, the opt::less is used.
- - opt::less - specifies binary predicate used for key comparison. Default is \p std::less<T>.
- - opt::disposer - the functor used for dispose removed items. Default is opt::v::empty_disposer. Due the nature
- of GC schema the disposer may be called asynchronously.
- - opt::item_counter - the type of item counting feature. Default is \ref atomicity::empty_item_counter that is no item counting.
- - opt::memory_model - C++ memory ordering model. Can be opt::v::relaxed_ordering (relaxed memory model, the default)
- or opt::v::sequential_consistent (sequentially consisnent memory model).
- - skip_list::random_level_generator - random level generator. Can be skip_list::xorshift, skip_list::turbo_pascal or
- user-provided one. See skip_list::random_level_generator option description for explanation.
- Default is \p %skip_list::turbo_pascal.
- - opt::allocator - although the skip-list is an intrusive container,
- an allocator should be provided to maintain variable randomly-calculated height of the node
- since the node can contain up to 32 next pointers. The allocator option is used to allocate an array of next pointers
- for nodes which height is more than 1. Default is \ref CDS_DEFAULT_ALLOCATOR.
- - opt::back_off - back-off strategy used. If the option is not specified, the cds::backoff::Default is used.
- - opt::stat - internal statistics. Available types: skip_list::stat, skip_list::empty_stat (the default)
-
- \warning The skip-list requires up to 67 hazard pointers that may be critical for some GCs for which
+ - \p GC - Garbage collector used. Note the \p GC must be the same as the GC used for item type \p T, see \p skip_list::node.
+ - \p T - type to be stored in the list. The type must be based on \p skip_list::node (for \p skip_list::base_hook)
+ or it must have a member of type \p skip_list::node (for \p skip_list::member_hook).
+ - \p Traits - skip-list traits, default is \p skip_list::traits.
+ It is possible to declare option-based list with \p cds::intrusive::skip_list::make_traits metafunction istead of \p Traits
+ template argument.
+
+ @warning The skip-list requires up to 67 hazard pointers that may be critical for some GCs for which
the guard count is limited (like as \p gc::HP). Those GCs should be explicitly initialized with
hazard pointer enough: \code cds::gc::HP myhp( 67 ) \endcode. Otherwise an run-time exception may be raised
when you try to create skip-list object.
- \note There are several specializations of \p %SkipListSet for each \p GC. You should include:
+ There are several specializations of \p %SkipListSet for each \p GC. You should include:
- <tt><cds/intrusive/skip_list_hp.h></tt> for \p gc::HP garbage collector
- <tt><cds/intrusive/skip_list_dhp.h></tt> for \p gc::DHP garbage collector
- - <tt><cds/intrusive/skip_list_nogc.h></tt> for \ref cds_intrusive_SkipListSet_nogc for persistent set
+ - <tt><cds/intrusive/skip_list_nogc.h></tt> for \ref cds_intrusive_SkipListSet_nogc for append-only set
- <tt><cds/intrusive/skip_list_rcu.h></tt> for \ref cds_intrusive_SkipListSet_rcu "RCU type"
<b>Iterators</b>
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 skip-list set it is not guarantee that you can iterate
+ @warning Due to concurrent nature of skip-list 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 2 additional hazard pointers, that may be
- a limited resource for \p GC like as \p gc::HP (for \p gc::PTB the count of
+ a limited resource for \p GC like as \p gc::HP (for \p gc::DHP the count of
guards is unlimited).
The iterator class supports the following minimalistic interface:
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.
+ Note, the iterator object returned by \p end(), \p cend() member functions points to \p nullptr and should not be dereferenced.
<b>How to use</b>
- You should incorporate skip_list::node into your struct \p T and provide
- appropriate skip_list::type_traits::hook in your \p Traits template parameters. Usually, for \p Traits you
- define a struct based on skip_list::type_traits.
+ You should incorporate \p skip_list::node into your struct \p T and provide
+ appropriate \p skip_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits you
+ define a struct based on \p skip_list::traits.
- Example for gc::HP and base hook:
+ Example for \p gc::HP and base hook:
\code
// Include GC-related skip-list specialization
#include <cds/intrusive/skip_list_hp.h>
};
- // Declare type_traits
- struct my_traits: public cds::intrusive::skip_list::type_traits
+ // Declare your traits
+ struct my_traits: public cds::intrusive::skip_list::traits
{
typedef cds::intrusive::skip_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
typedef my_data_cmp compare;
class GC
,typename T
#ifdef CDS_DOXYGEN_INVOKED
- ,typename Traits = skip_list::type_traits
+ ,typename Traits = skip_list::traits
#else
,typename Traits
#endif
class SkipListSet
{
public:
- typedef T value_type ; ///< type of value stored in the skip-list
- typedef Traits options ; ///< Traits template parameter
+ typedef GC gc; ///< Garbage collector
+ typedef T value_type; ///< type of value stored in the skip-list
+ typedef Traits traits; ///< Traits template parameter
- typedef typename options::hook hook ; ///< hook type
- typedef typename hook::node_type node_type ; ///< node type
+ typedef typename traits::hook hook; ///< hook type
+ typedef typename hook::node_type node_type; ///< node type
# ifdef CDS_DOXYGEN_INVOKED
typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
# else
- typedef typename opt::details::make_comparator< value_type, options >::type key_comparator;
+ typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
# endif
- typedef typename options::disposer disposer ; ///< disposer used
- typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
+ typedef typename traits::disposer disposer; ///< item disposer
+ typedef typename get_node_traits< value_type, node_type, hook>::type node_traits; ///< node traits
- typedef GC gc ; ///< Garbage collector
- typedef typename options::item_counter item_counter ; ///< Item counting policy used
- typedef typename options::memory_model memory_model ; ///< Memory ordering. See cds::opt::memory_model option
- typedef typename options::random_level_generator random_level_generator ; ///< random level generator
- typedef typename options::allocator allocator_type ; ///< allocator for maintaining array of next pointers of the node
- typedef typename options::back_off back_off ; ///< Back-off strategy
- typedef typename options::stat stat ; ///< internal statistics type
+ typedef typename traits::item_counter item_counter; ///< Item counting policy
+ typedef typename traits::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model option
+ typedef typename traits::random_level_generator random_level_generator; ///< random level generator
+ typedef typename traits::allocator allocator_type; ///< allocator for maintaining array of next pointers of the node
+ typedef typename traits::back_off back_off; ///< Back-off strategy
+ typedef typename traits::stat stat; ///< internal statistics type
public:
- typedef cds::gc::guarded_ptr< gc, value_type > guarded_ptr; ///< Guarded pointer
+ typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
/// Max node height. The actual node height should be in range <tt>[0 .. c_nMaxHeight)</tt>
/**
The max height is specified by \ref skip_list::random_level_generator "random level generator" constant \p m_nUpperBound
- but it should be no more than 32 (\ref skip_list::c_nHeightLimit).
+ but it should be no more than 32 (\p skip_list::c_nHeightLimit).
*/
static unsigned int const c_nMaxHeight = std::conditional<
(random_level_generator::c_nUpperBound <= skip_list::c_nHeightLimit),
static unsigned int const c_nMinHeight = 5;
//@endcond
+ // c_nMaxHeight * 2 - pPred/pSucc guards
+ // + 1 - for erase, unlink
+ // + 1 - for clear
+ static size_t const c_nHazardPtrCount = c_nMaxHeight * 2 + 2; ///< Count of hazard pointer required for the skip-list
+
protected:
- typedef typename node_type::atomic_marked_ptr atomic_node_ptr ; ///< Atomic marked node pointer
- typedef typename node_type::marked_ptr marked_node_ptr ; ///< Node marked pointer
+ typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic marked node pointer
+ typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
protected:
//@cond
typedef skip_list::details::intrusive_node_builder< node_type, atomic_node_ptr, allocator_type > intrusive_node_builder;
typedef typename std::conditional<
- std::is_same< typename options::internal_node_builder, cds::opt::none >::value
+ std::is_same< typename traits::internal_node_builder, cds::opt::none >::value
,intrusive_node_builder
- ,typename options::internal_node_builder
+ ,typename traits::internal_node_builder
>::type node_builder;
- typedef std::unique_ptr< node_type, typename node_builder::node_disposer > scoped_node_ptr;
+ typedef std::unique_ptr< node_type, typename node_builder::node_disposer > scoped_node_ptr;
- // c_nMaxHeight * 2 - pPred/pSucc guards
- // + 1 - for erase, unlink
- // + 1 - for clear
- static size_t const c_nHazardPtrCount = c_nMaxHeight * 2 + 2;
struct position {
node_type * pPrev[ c_nMaxHeight ];
node_type * pSucc[ c_nMaxHeight ];
- typename gc::template GuardArray< c_nMaxHeight * 2 > guards ; ///< Guards array for pPrev/pSucc
-
- node_type * pCur ; // guarded by guards; needed only for *ensure* function
+ typename gc::template GuardArray< c_nMaxHeight * 2 > guards; ///< Guards array for pPrev/pSucc
+ node_type * pCur; // guarded by guards; needed only for \p update()
};
//@endcond
protected:
- skip_list::details::head_node< node_type > m_Head ; ///< head tower (max height)
+ skip_list::details::head_node< node_type > m_Head; ///< head tower (max height)
- item_counter m_ItemCounter ; ///< item counter
- random_level_generator m_RandomLevelGen ; ///< random level generator instance
- atomics::atomic<unsigned int> m_nHeight ; ///< estimated high level
- mutable stat m_Stat ; ///< internal statistics
+ item_counter m_ItemCounter; ///< item counter
+ random_level_generator m_RandomLevelGen; ///< random level generator instance
+ atomics::atomic<unsigned int> m_nHeight; ///< estimated high level
+ mutable stat m_Stat; ///< internal statistics
protected:
//@cond
static value_type * gc_protect( marked_node_ptr p )
{
- return node_traits::to_value_ptr( p.ptr() );
+ return node_traits::to_value_ptr( p.ptr());
}
static void dispose_node( value_type * pVal )
{
assert( pVal != nullptr );
- typename node_builder::node_disposer()( node_traits::to_node_ptr(pVal) );
+ typename node_builder::node_disposer()( node_traits::to_node_ptr(pVal));
disposer()( pVal );
}
pos.guards.assign( nLevel * 2, node_traits::to_value_ptr( pPred ));
while ( true ) {
pCur = pos.guards.protect( nLevel * 2 + 1, pPred->next( nLevel ), gc_protect );
- if ( pCur.bits() ) {
+ if ( pCur.bits()) {
// pCur.bits() means that pPred is logically deleted
goto retry;
}
}
// pSucc contains deletion mark for pCur
- pSucc = pCur->next( nLevel ).load( memory_model::memory_order_relaxed );
+ pSucc = pCur->next( nLevel ).load( memory_model::memory_order_acquire );
- if ( pPred->next( nLevel ).load( memory_model::memory_order_relaxed ).all() != pCur.ptr() )
+ if ( pPred->next( nLevel ).load( memory_model::memory_order_acquire ).all() != pCur.ptr())
goto retry;
- if ( pSucc.bits() ) {
+ if ( pSucc.bits()) {
// pCur is marked, i.e. logically deleted.
- marked_node_ptr p( pCur.ptr() );
- if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr() ),
- memory_model::memory_order_release, atomics::memory_order_relaxed ))
+ marked_node_ptr p( pCur.ptr());
+ if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr()),
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
{
if ( nLevel == 0 ) {
- gc::retire( node_traits::to_value_ptr( pCur.ptr() ), dispose_node );
+ gc::retire( node_traits::to_value_ptr( pCur.ptr()), dispose_node );
m_Stat.onEraseWhileFind();
}
}
// head cannot be deleted
assert( pCur.bits() == 0 );
- if ( pCur.ptr() ) {
+ if ( pCur.ptr()) {
// pSucc contains deletion mark for pCur
- pSucc = pCur->next( nLevel ).load( memory_model::memory_order_relaxed );
+ pSucc = pCur->next( nLevel ).load( memory_model::memory_order_acquire );
- if ( pPred->next( nLevel ).load( memory_model::memory_order_relaxed ).all() != pCur.ptr() )
+ if ( pPred->next( nLevel ).load( memory_model::memory_order_acquire ).all() != pCur.ptr())
goto retry;
- if ( pSucc.bits() ) {
+ if ( pSucc.bits()) {
// pCur is marked, i.e. logically deleted.
- marked_node_ptr p( pCur.ptr() );
- if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr() ),
- memory_model::memory_order_release, atomics::memory_order_relaxed ))
+ marked_node_ptr p( pCur.ptr());
+ if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr()),
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
{
- if ( nLevel == 0 )
- gc::retire( node_traits::to_value_ptr( pCur.ptr() ), dispose_node );
+ if ( nLevel == 0 ) {
+ gc::retire( node_traits::to_value_ptr( pCur.ptr()), dispose_node );
+ m_Stat.onEraseWhileFind();
+ }
}
goto retry;
}
pos.guards.assign( nLevel * 2, node_traits::to_value_ptr( pPred ));
while ( true ) {
pCur = pos.guards.protect( nLevel * 2 + 1, pPred->next( nLevel ), gc_protect );
- if ( pCur.bits() ) {
+ if ( pCur.bits()) {
// pCur.bits() means that pPred is logically deleted
goto retry;
}
}
// pSucc contains deletion mark for pCur
- pSucc = pCur->next( nLevel ).load( memory_model::memory_order_relaxed );
+ pSucc = pCur->next( nLevel ).load( memory_model::memory_order_acquire );
- if ( pPred->next( nLevel ).load( memory_model::memory_order_relaxed ).all() != pCur.ptr() )
+ if ( pPred->next( nLevel ).load( memory_model::memory_order_acquire ).all() != pCur.ptr())
goto retry;
- if ( pSucc.bits() ) {
+ if ( pSucc.bits()) {
// pCur is marked, i.e. logically deleted.
- marked_node_ptr p( pCur.ptr() );
- if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr() ),
- memory_model::memory_order_release, atomics::memory_order_relaxed ))
+ marked_node_ptr p( pCur.ptr());
+ if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr()),
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
{
- if ( nLevel == 0 )
- gc::retire( node_traits::to_value_ptr( pCur.ptr() ), dispose_node );
+ if ( nLevel == 0 ) {
+ gc::retire( node_traits::to_value_ptr( pCur.ptr()), dispose_node );
+ m_Stat.onEraseWhileFind();
+ }
}
goto retry;
}
else {
- if ( !pSucc.ptr() )
+ if ( !pSucc.ptr())
break;
pPred = pCur.ptr();
for ( unsigned int nLevel = 1; nLevel < nHeight; ++nLevel )
pNode->next(nLevel).store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ // Insert at level 0
{
marked_node_ptr p( pos.pSucc[0] );
pNode->next( 0 ).store( p, memory_model::memory_order_release );
- if ( !pos.pPrev[0]->next(0).compare_exchange_strong( p, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed ) ) {
+ if ( !pos.pPrev[0]->next(0).compare_exchange_strong( p, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed ))
return false;
- }
+
f( val );
}
+ // Insert at level 1..max
for ( unsigned int nLevel = 1; nLevel < nHeight; ++nLevel ) {
marked_node_ptr p;
while ( true ) {
if ( !pNode->next( nLevel ).compare_exchange_strong( p, q, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
// pNode has been marked as removed while we are inserting it
// Stop inserting
- assert( p.bits() );
+ assert( p.bits());
m_Stat.onLogicDeleteWhileInsert();
return true;
}
p = q;
- if ( pos.pPrev[nLevel]->next(nLevel).compare_exchange_strong( q, marked_node_ptr( pNode ), memory_model::memory_order_release, atomics::memory_order_relaxed ) )
+ if ( pos.pPrev[nLevel]->next(nLevel).compare_exchange_strong( q, marked_node_ptr( pNode ), memory_model::memory_order_release, atomics::memory_order_relaxed ))
break;
// Renew insert position
assert( pDel != nullptr );
marked_node_ptr pSucc;
- typename gc::Guard gSucc;
// logical deletion (marking)
for ( unsigned int nLevel = pDel->height() - 1; nLevel > 0; --nLevel ) {
while ( true ) {
- pSucc = gSucc.protect( pDel->next(nLevel), gc_protect );
+ pSucc = pDel->next(nLevel);
if ( pSucc.bits() || pDel->next(nLevel).compare_exchange_weak( pSucc, pSucc | 1,
- memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
+ memory_model::memory_order_release, atomics::memory_order_relaxed ))
{
break;
}
}
while ( true ) {
- pSucc = gSucc.protect( pDel->next(0), gc_protect );
- marked_node_ptr p( pSucc.ptr() );
- if ( pDel->next(0).compare_exchange_strong( p, marked_node_ptr(p.ptr(), 1),
- memory_model::memory_order_acquire, atomics::memory_order_relaxed ))
+ marked_node_ptr p( pDel->next(0).load(memory_model::memory_order_relaxed).ptr());
+ if ( pDel->next(0).compare_exchange_strong( p, p | 1, memory_model::memory_order_release, atomics::memory_order_relaxed ))
{
f( *node_traits::to_value_ptr( pDel ));
// try fast erase
p = pDel;
for ( int nLevel = static_cast<int>( pDel->height() - 1 ); nLevel >= 0; --nLevel ) {
- pSucc = gSucc.protect( pDel->next(nLevel), gc_protect );
+ pSucc = pDel->next(nLevel).load(memory_model::memory_order_relaxed);
if ( !pos.pPrev[nLevel]->next(nLevel).compare_exchange_strong( p, marked_node_ptr(pSucc.ptr()),
- memory_model::memory_order_release, atomics::memory_order_relaxed) )
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed))
{
// Make slow erase
find_position( *node_traits::to_value_ptr( pDel ), pos, key_comparator(), false );
return true;
}
else {
- if ( p.bits() ) {
+ if ( p.bits()) {
+ // Another thread is deleting pDel right now
return false;
}
}
+ m_Stat.onEraseRetry();
}
}
continue;
while ( pCur != pNull ) {
- if ( pCur.bits() ) {
+ if ( pCur.bits()) {
unsigned int nAttempt = 0;
while ( pCur.bits() && nAttempt++ < 16 ) {
bkoff();
}
bkoff.reset();
- if ( pCur.bits() ) {
+ if ( pCur.bits()) {
// Maybe, we are on deleted node sequence
// Abort searching, try slow-path
return find_fastpath_abort;
}
}
- if ( pCur.ptr() ) {
- int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr() ), val );
+ if ( pCur.ptr()) {
+ int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr()), val );
if ( nCmp < 0 ) {
guards.copy( 0, 1 );
pPred = pCur.ptr();
}
else if ( nCmp == 0 ) {
// found
- f( *node_traits::to_value_ptr( pCur.ptr() ), val );
+ f( *node_traits::to_value_ptr( pCur.ptr()), val );
return find_fastpath_found;
}
else // pCur > val - go down
}
template <typename Q, typename Compare>
- bool get_with_( typename gc::Guard& guard, Q const& val, Compare cmp )
+ guarded_ptr get_with_( Q const& val, Compare cmp )
{
- return find_with_( val, cmp, [&guard](value_type& found, Q const& ) { guard.assign(&found); } );
+ guarded_ptr gp;
+ if ( find_with_( val, cmp, [&gp](value_type& found, Q const& ) { gp.reset(&found); } ))
+ return gp;
+ return guarded_ptr();
}
template <typename Q, typename Compare, typename Func>
{
position pos;
- if ( !find_position( val, pos, cmp, false ) ) {
+ if ( !find_position( val, pos, cmp, false )) {
m_Stat.onEraseFailed();
return false;
}
node_type * pDel = pos.pCur;
typename gc::Guard gDel;
- gDel.assign( node_traits::to_value_ptr(pDel) );
+ gDel.assign( node_traits::to_value_ptr(pDel));
assert( cmp( *node_traits::to_value_ptr( pDel ), val ) == 0 );
unsigned int nHeight = pDel->height();
}
template <typename Q, typename Compare>
- bool extract_( typename gc::Guard& guard, Q const& val, Compare cmp )
+ guarded_ptr extract_( Q const& val, Compare cmp )
{
position pos;
+ guarded_ptr gp;
for (;;) {
- if ( !find_position( val, pos, cmp, false ) ) {
+ if ( !find_position( val, pos, cmp, false )) {
m_Stat.onExtractFailed();
- return false;
+ return guarded_ptr();
}
node_type * pDel = pos.pCur;
- guard.assign( node_traits::to_value_ptr(pDel));
+ gp.reset( node_traits::to_value_ptr( pDel ));
assert( cmp( *node_traits::to_value_ptr( pDel ), val ) == 0 );
unsigned int nHeight = pDel->height();
--m_ItemCounter;
m_Stat.onRemoveNode( nHeight );
m_Stat.onExtractSuccess();
- return true;
+ return gp;
}
-
m_Stat.onExtractRetry();
}
}
- bool extract_min_( typename gc::Guard& gDel )
+ guarded_ptr extract_min_()
{
position pos;
+ guarded_ptr gp;
for (;;) {
- if ( !find_min_position( pos ) ) {
+ if ( !find_min_position( pos )) {
// The list is empty
m_Stat.onExtractMinFailed();
- return false;
+ return guarded_ptr();
}
node_type * pDel = pos.pCur;
unsigned int nHeight = pDel->height();
- gDel.assign( node_traits::to_value_ptr(pDel) );
+ gp.reset( node_traits::to_value_ptr(pDel));
if ( try_remove_at( pDel, pos, [](value_type const&) {} )) {
--m_ItemCounter;
m_Stat.onRemoveNode( nHeight );
m_Stat.onExtractMinSuccess();
- return true;
+ return gp;
}
m_Stat.onExtractMinRetry();
}
}
- bool extract_max_( typename gc::Guard& gDel )
+ guarded_ptr extract_max_()
{
position pos;
+ guarded_ptr gp;
for (;;) {
- if ( !find_max_position( pos ) ) {
+ if ( !find_max_position( pos )) {
// The list is empty
m_Stat.onExtractMaxFailed();
- return false;
+ return guarded_ptr();
}
node_type * pDel = pos.pCur;
unsigned int nHeight = pDel->height();
- gDel.assign( node_traits::to_value_ptr(pDel) );
+ gp.reset( node_traits::to_value_ptr(pDel));
if ( try_remove_at( pDel, pos, [](value_type const&) {} )) {
--m_ItemCounter;
m_Stat.onRemoveNode( nHeight );
m_Stat.onExtractMaxSuccess();
- return true;
+ return gp;
}
m_Stat.onExtractMaxRetry();
}
public:
+ ///@name Forward iterators (only for debugging purpose)
+ //@{
/// Iterator type
+ /**
+ The forward iterator 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 ensures thread-safety even if you delete the item the iterator points to. However, in case of concurrent
+ deleting operations there is no guarantee that you iterate all item in the list.
+ Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
+
+ @warning Use this iterator on the concurrent container for debugging purpose only.
+
+ 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 skip_list::details::iterator< gc, node_traits, back_off, false > iterator;
/// Const iterator type
/// Returns a forward iterator addressing the first element in a set
iterator begin()
{
- return iterator( *m_Head.head() );
+ return iterator( *m_Head.head());
}
/// Returns a forward const iterator addressing the first element in a set
- //@{
const_iterator begin() const
{
- return const_iterator( *m_Head.head() );
+ return const_iterator( *m_Head.head());
}
+ /// Returns a forward const iterator addressing the first element in a set
const_iterator cbegin() const
{
- return const_iterator( *m_Head.head() );
+ return const_iterator( *m_Head.head());
}
- //@}
/// Returns a forward iterator that addresses the location succeeding the last element in a set.
iterator end()
}
/// Returns a forward const iterator that addresses the location succeeding the last element in a set.
- //@{
const_iterator end() const
{
return const_iterator();
}
+ /// Returns a forward const iterator that addresses the location succeeding the last element in a set.
const_iterator cend() const
{
return const_iterator();
}
- //@}
+ //@}
public:
/// Inserts new node
\endcode
where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
\p val no any other changes could be made on this set's item by concurrent threads.
- The user-defined functor is called only if the inserting is success and may be passed by reference
- using \p std::ref
+ The user-defined functor is called only if the inserting is success.
*/
template <typename Func>
bool insert( value_type& val, Func f )
position pos;
while ( true )
{
- bool bFound = find_position( val, pos, key_comparator(), true );
- if ( bFound ) {
+ if ( find_position( val, pos, key_comparator(), true )) {
// scoped_node_ptr deletes the node tower if we create it
if ( !bTowerMade )
scp.release();
}
}
- /// Ensures that the \p val exists in the set
+ /// Updates the node
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val is not found in the set, then \p val is inserted into the set.
+ If the item \p val is not found in the set, then \p val is inserted into the set
+ iff \p bInsert 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 - item of the set
- - \p val - argument \p val passed into the \p ensure function
+ - \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.
- The functor can change non-key fields of the \p item; however, \p func must guarantee
- that during changing no any other modifications could be made on this item by concurrent threads.
-
- You can pass \p func argument by value or by reference using \p std::ref.
-
- Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
+ Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
+ 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 set.
+ 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 bInsert = true )
{
typename gc::Guard gNew;
gNew.assign( &val );
scp.release();
func( false, *node_traits::to_value_ptr(pos.pCur), val );
- m_Stat.onEnsureExist();
+ m_Stat.onUpdateExist();
return std::make_pair( true, false );
}
+ if ( !bInsert ) {
+ scp.release();
+ return std::make_pair( false, false );
+ }
+
if ( !bTowerOk ) {
build_node( pNode );
nHeight = pNode->height();
++m_ItemCounter;
scp.release();
m_Stat.onAddNode( nHeight );
- m_Stat.onEnsureNew();
+ m_Stat.onUpdateNew();
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 set
/**
The function searches the item \p val in the set and unlink it from the set
if it is found and is equal to \p val.
- Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
- and deletes the item found. \p unlink finds an item by key and deletes it
+ Difference between \p erase() and \p %unlink() functions: \p %erase() finds <i>a key</i>
+ and deletes the item found. \p %unlink() finds an item by key and deletes it
only if \p val is an item of that set, i.e. the pointer to item found
is equal to <tt> &val </tt>.
- The \ref disposer specified in \p Traits class template parameter is called
+ The \p disposer specified in \p Traits class template parameter is called
by garbage collector \p GC asynchronously.
The function returns \p true if success and \p false otherwise.
{
position pos;
- if ( !find_position( val, pos, key_comparator(), false ) ) {
+ if ( !find_position( val, pos, key_comparator(), false )) {
m_Stat.onUnlinkFailed();
return false;
}
unsigned int nHeight = pDel->height();
typename gc::Guard gDel;
- gDel.assign( node_traits::to_value_ptr(pDel) );
+ gDel.assign( node_traits::to_value_ptr(pDel));
if ( node_traits::to_value_ptr( pDel ) == &val && try_remove_at( pDel, pos, [](value_type const&) {} )) {
--m_ItemCounter;
/// Extracts the item from the set with specified \p key
/** \anchor cds_intrusive_SkipListSet_hp_extract
The function searches an item with key equal to \p key in the set,
- 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 set, and returns it as \p guarded_ptr object.
+ If \p key is not found the function returns an empty guarded pointer.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
- The \ref disposer specified in \p Traits class template parameter is called automatically
- by garbage collector \p GC specified in class' template parameters when returned \ref guarded_ptr object
+ The \p disposer specified in \p Traits class template parameter is called automatically
+ by garbage collector \p GC specified in class' template parameters 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.
skip_list theList;
// ...
{
- skip_list::guarded_ptr gp;
- theList.extract( gp, 5 );
- // Deal with gp
- // ...
-
+ skip_list::guarded_ptr gp(theList.extract( 5 ));
+ if ( gp ) {
+ // Deal with gp
+ // ...
+ }
// Destructor of gp releases internal HP guard
}
\endcode
*/
template <typename Q>
- bool extract( guarded_ptr& dest, Q const& key )
+ guarded_ptr extract( Q const& key )
{
- return extract_( dest.guard(), key, key_comparator() );
+ return extract_( key, key_comparator());
}
/// Extracts the item from the set with comparing functor \p pred
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less>
- bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
+ guarded_ptr extract_with( Q const& key, Less pred )
{
- return extract_( dest.guard(), key, cds::opt::details::make_comparator_from_less<Less>() );
+ CDS_UNUSED( pred );
+ return extract_( key, cds::opt::details::make_comparator_from_less<Less>());
}
/// Extracts an item with minimal key from the list
/**
- The function searches an item with minimal key, unlinks it, and returns the item found in \p dest parameter.
- If the skip-list is empty the function returns \p false.
+ The function searches an item with minimal key, unlinks it, and returns it as \p guarded_ptr object.
+ If the skip-list is empty the function returns an empty guarded pointer.
@note Due the concurrent nature of the list, the function extracts <i>nearly</i> minimum key.
It means that the function gets leftmost item and tries to unlink it.
During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
So, the function returns the item with minimum key at the moment of list traversing.
- The \ref disposer specified in \p Traits class template parameter is called
- by garbage collector \p GC automatically when returned \ref guarded_ptr object
+ The \p disposer specified in \p Traits class template parameter is called
+ by garbage collector \p GC 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.
skip_list theList;
// ...
{
- skip_list::guarded_ptr gp;
- if ( theList.extract_min( gp )) {
+ skip_list::guarded_ptr gp(theList.extract_min());
+ if ( gp ) {
// Deal with gp
//...
}
}
\endcode
*/
- bool extract_min( guarded_ptr& dest)
+ guarded_ptr extract_min()
{
- return extract_min_( dest.guard() );
+ return extract_min_();
}
/// Extracts an item with maximal key from the list
/**
- The function searches an item with maximal key, unlinks it, and returns the pointer to item found in \p dest parameter.
- If the skip-list is empty the function returns empty \p guarded_ptr.
+ The function searches an item with maximal key, unlinks it, and returns the pointer to item
+ as \p guarded_ptr object.
+ If the skip-list is empty the function returns an empty \p guarded_ptr.
@note Due the concurrent nature of the list, the function extracts <i>nearly</i> maximal key.
It means that the function gets rightmost item and tries to unlink it.
During unlinking, a concurrent thread may insert an item with key greater than rightmost item's key.
So, the function returns the item with maximum key at the moment of list traversing.
- The \ref disposer specified in \p Traits class template parameter is called
+ The \p disposer specified in \p Traits class template parameter is called
by garbage collector \p GC asynchronously when returned \ref 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:
\code
- typedef cds::intrusive::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
+ typedef cds::intrusive::SkipListSet< cds::gc::HP, foo, my_traits > skip_list;
skip_list theList;
// ...
{
- skip_list::guarded_ptr gp;
- if ( theList.extract_max( gp )) {
+ skip_list::guarded_ptr gp( theList.extract_max( gp ));
+ if ( gp ) {
// Deal with gp
//...
}
}
\endcode
*/
- bool extract_max( guarded_ptr& dest )
+ guarded_ptr extract_max()
{
- return extract_max_( dest.guard() );
+ return extract_max_();
}
/// Deletes the item from the set
/** \anchor cds_intrusive_SkipListSet_hp_erase
- The function searches an item with key equal to \p val in the set,
+ The function searches an item with key equal to \p key in the set,
unlinks it from the set, and returns \p true.
- If the item with key equal to \p val is not found the function return \p false.
+ If the item with key equal to \p key is not found the function return \p false.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
*/
template <typename Q>
- bool erase( Q const& val )
+ bool erase( Q const& key )
{
- return erase_( val, key_comparator(), [](value_type const&) {} );
+ return erase_( key, key_comparator(), [](value_type const&) {} );
}
/// Deletes the item from the set with comparing functor \p pred
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less>
- bool erase_with( Q const& val, Less pred )
+ bool erase_with( Q const& key, Less pred )
{
- return erase_( val, cds::opt::details::make_comparator_from_less<Less>(), [](value_type const&) {} );
+ CDS_UNUSED( pred );
+ return erase_( key, cds::opt::details::make_comparator_from_less<Less>(), [](value_type const&) {} );
}
/// Deletes the item from the set
/** \anchor cds_intrusive_SkipListSet_hp_erase_func
- The function searches an item with key equal to \p val in the set,
+ The function searches an item with key equal to \p key in the set,
call \p f functor with item found, unlinks it from the set, and returns \p true.
The \ref disposer specified in \p Traits class template parameter is called
by garbage collector \p GC asynchronously.
void operator()( value_type const& item );
};
\endcode
- The functor can be passed by reference with <tt>boost:ref</tt>
- If the item with key equal to \p val is not found the function return \p false.
+ If the item with key equal to \p key is not found the function return \p false.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
*/
template <typename Q, typename Func>
- bool erase( Q const& val, Func f )
+ bool erase( Q const& key, Func f )
{
- return erase_( val, key_comparator(), f );
+ return erase_( key, key_comparator(), f );
}
/// Deletes the item from the set with comparing functor \p pred
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less, typename Func>
- bool erase_with( Q const& val, Less pred, Func f )
+ bool erase_with( Q const& key, Less pred, Func f )
{
- return erase_( val, cds::opt::details::make_comparator_from_less<Less>(), f );
+ CDS_UNUSED( pred );
+ return erase_( key, cds::opt::details::make_comparator_from_less<Less>(), f );
}
- /// Finds the key \p val
+ /// Finds \p key
/** \anchor cds_intrusive_SkipListSet_hp_find_func
- The function searches the item with key equal to \p val and calls the functor \p f for item found.
+ The function searches the item with key equal to \p key and calls the functor \p f for item found.
The interface of \p Func functor is:
\code
struct functor {
- void operator()( value_type& item, Q& val );
+ void operator()( value_type& item, Q& key );
};
\endcode
- where \p item is the item found, \p val is the <tt>find</tt> function argument.
-
- You can pass \p f argument by value or by reference using \p std::ref.
+ where \p item is the item found, \p key is the <tt>find</tt> function argument.
The functor can change non-key fields of \p item. 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 set \p item. If such access is
- possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
-
- The \p val argument is non-const since it can be used as \p f functor destination i.e., the functor
- can modify both arguments.
+ possible you must provide your own synchronization on item level to exclude unsafe item modifications.
Note the compare 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.
- The function returns \p true if \p val is found, \p false otherwise.
+ The function returns \p true if \p key is found, \p false otherwise.
*/
template <typename Q, typename Func>
- bool find( Q& val, Func f )
+ bool find( Q& key, Func f )
+ {
+ return find_with_( key, key_comparator(), f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
{
- return find_with_( val, key_comparator(), f );
+ return find_with_( key, key_comparator(), f );
}
+ //@endcond
- /// Finds the key \p val with \p pred predicate for comparing
+ /// Finds the key \p key with \p pred predicate for comparing
/**
The function is an analog of \ref cds_intrusive_SkipListSet_hp_find_func "find(Q&, Func)"
but \p pred is used for key compare.
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less, typename Func>
- bool find_with( Q& val, Less pred, Func f )
+ bool find_with( Q& key, Less pred, Func f )
{
- return find_with_( val, cds::opt::details::make_comparator_from_less<Less>(), f );
+ CDS_UNUSED( pred );
+ return find_with_( key, cds::opt::details::make_comparator_from_less<Less>(), f );
}
-
- /// Finds the key \p val
- /** \anchor cds_intrusive_SkipListSet_hp_find_cfunc
- The function searches the item with key equal to \p val and calls the functor \p f for item found.
- The interface of \p Func functor is:
- \code
- struct functor {
- void operator()( value_type& item, Q const& val );
- };
- \endcode
- where \p item is the item found, \p val is the <tt>find</tt> function argument.
-
- You can pass \p f argument by value or by reference using \p std::ref.
-
- The functor can change non-key fields of \p item. 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 set \p item. If such access is
- possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
-
- Note the compare 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.
-
- The function returns \p true if \p val is found, \p false otherwise.
- */
- template <typename Q, typename Func>
- bool find( Q const& val, Func f )
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
{
- return find_with_( val, key_comparator(), f );
+ CDS_UNUSED( pred );
+ return find_with_( key, cds::opt::details::make_comparator_from_less<Less>(), f );
}
+ //@endcond
- /// Finds the key \p val with \p pred predicate for comparing
+ /// Checks whether the set contains \p key
/**
- The function is an analog of \ref cds_intrusive_SkipListSet_hp_find_cfunc "find(Q const&, Func)"
- but \p pred is used for key compare.
- \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
- in any order.
- \p pred must imply the same element order as the comparator used for building the set.
+ 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 Q, typename Less, typename Func>
- bool find_with( Q const& val, Less pred, Func f )
+ template <typename Q>
+ bool contains( Q const& key )
{
- return find_with_( val, cds::opt::details::make_comparator_from_less<Less>(), f );
+ return find_with_( key, key_comparator(), [](value_type& , Q const& ) {} );
}
-
- /// Finds the key \p val
- /** \anchor cds_intrusive_SkipListSet_hp_find_val
- The function searches the item with key equal to \p val
- and returns \p true if it is found, and \p false otherwise.
-
- Note the compare 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.
- */
+ //@cond
template <typename Q>
- bool find( Q const & val )
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
{
- return find_with_( val, key_comparator(), [](value_type& , Q const& ) {} );
+ return contains( key );
}
+ //@endcond
- /// Finds the key \p val 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_SkipListSet_hp_find_val "find(Q 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 value_type and \p Q
- in any order.
- \p pred must imply the same element order as the comparator used for building the set.
+ 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& val, Less pred )
+ bool contains( Q const& key, Less pred )
{
- return find_with_( val, cds::opt::details::make_comparator_from_less<Less>(), [](value_type& , Q const& ) {} );
+ CDS_UNUSED( pred );
+ return find_with_( key, cds::opt::details::make_comparator_from_less<Less>(), [](value_type& , Q const& ) {} );
}
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
- /// Finds the key \p val and return the item found
+ /// Finds \p key and return the item found
/** \anchor cds_intrusive_SkipListSet_hp_get
- The function searches the item with key equal to \p val
- and assigns the item found to guarded pointer \p ptr.
- The function returns \p true if \p val is found, and \p false otherwise.
- If \p val is not found the \p ptr parameter is not changed.
+ The function searches the item with key equal to \p key
+ and returns the pointer to the item found as \p guarded_ptr.
+ If \p key is not found the function returns an empt guarded pointer.
- The \ref disposer specified in \p Traits class template parameter is called
+ The \p disposer specified in \p Traits class template parameter is called
by garbage collector \p GC asynchronously when returned \ref guarded_ptr object
will be destroyed or released.
@note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
skip_list theList;
// ...
{
- skip_list::guarded_ptr gp;
- if ( theList.get( gp, 5 )) {
+ skip_list::guarded_ptr gp(theList.get( 5 ));
+ if ( gp ) {
// Deal with gp
//...
}
should accept a parameter of type \p Q that can be not the same as \p value_type.
*/
template <typename Q>
- bool get( guarded_ptr& ptr, Q const& val )
+ guarded_ptr get( Q const& key )
{
- return get_with_( ptr.guard(), val, key_comparator() );
+ return get_with_( key, key_comparator());
}
- /// Finds the key \p val and return the item found
+ /// Finds \p key and return the item found
/**
- The function is an analog of \ref cds_intrusive_SkipListSet_hp_get "get( guarded_ptr& ptr, Q const&)"
+ The function is an analog of \ref cds_intrusive_SkipListSet_hp_get "get( Q 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 value_type and \p Q
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less>
- bool get_with( guarded_ptr& ptr, Q const& val, Less pred )
+ guarded_ptr get_with( Q const& key, Less pred )
{
- return get_with_( ptr.guard(), val, cds::opt::details::make_comparator_from_less<Less>() );
+ CDS_UNUSED( pred );
+ return get_with_( key, cds::opt::details::make_comparator_from_less<Less>());
}
/// Returns item count in the set
/**
The value returned depends on item counter type provided by \p Traits template parameter.
- If it is atomicity::empty_item_counter this function always returns 0.
- Therefore, the function is not suitable for checking the set emptiness, use \ref empty
- member function for this purpose.
+ If it is \p atomicity::empty_item_counter this function always returns 0.
+ Therefore, the function is not suitable for checking the set emptiness, use \p empty()
+ for this purpose.
*/
size_t size() const
{
return m_Head.head()->next( 0 ).load( memory_model::memory_order_relaxed ) == nullptr;
}
- /// Clears the set (non-atomic)
+ /// Clears the set (not atomic)
/**
The function unlink all items from the set.
The function is not atomic, i.e., in multi-threaded environment with parallel insertions
this sequence
\code
set.clear();
- assert( set.empty() );
+ assert( set.empty());
\endcode
the assertion could be raised.
*/
void clear()
{
- guarded_ptr gp;
- while ( extract_min( gp ));
+ while ( extract_min_());
}
/// Returns maximum height of skip-list. The max height is a constant for each object and does not exceed 32.
{
return m_Stat;
}
-
};
}} // namespace cds::intrusive
-#endif // #ifndef __CDS_INTRUSIVE_IMPL_SKIP_LIST_H
+#endif // #ifndef CDSLIB_INTRUSIVE_IMPL_SKIP_LIST_H
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