/*
This file is a part of libcds - Concurrent Data Structures library
- (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
Source code repo: http://github.com/khizmax/libcds/
Download: http://sourceforge.net/projects/libcds/files/
-
+
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
*/
typedef opt::none less;
- /// Type of mutual-exclusion lock
+ /// Type of mutual-exclusion lock. The lock is not need to be recursive.
typedef cds::sync::spin lock_type;
/// Back-off strategy
- typedef backoff::yield back_off;
+ typedef backoff::Default back_off;
/// Internal statistics
/**
typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
# endif
- typedef typename traits::lock_type lock_type; ///< heap's size lock type
- typedef typename traits::back_off back_off; ///< Back-off strategy
- typedef typename traits::stat stat; ///< internal statistics type
+ typedef typename traits::lock_type lock_type; ///< heap's size lock type
+ typedef typename traits::back_off back_off; ///< Back-off strategy
+ typedef typename traits::stat stat; ///< internal statistics type, see \p mspriority_queue::traits::stat
+ typedef typename cds::bitop::bit_reverse_counter<> item_counter;///< Item counter type
protected:
//@cond
/// Creates empty node
node()
: m_pVal( nullptr )
- , m_nTag( tag_type(Empty) )
+ , m_nTag( tag_type(Empty))
{}
/// Lock the node
typedef typename traits::buffer::template rebind<node>::other buffer_type ; ///< Heap array buffer type
//@cond
- typedef cds::bitop::bit_reverse_counter<> item_counter_type;
- typedef typename item_counter_type::counter_type counter_type;
+ typedef typename item_counter::counter_type counter_type;
//@endcond
protected:
- item_counter_type m_ItemCounter ; ///< Item counter
+ item_counter m_ItemCounter ; ///< Item counter
mutable lock_type m_Lock ; ///< Heap's size lock
buffer_type m_Heap ; ///< Heap array
stat m_Stat ; ///< internal statistics accumulator
// Insert new item at bottom of the heap
m_Lock.lock();
- if ( m_ItemCounter.value() >= capacity() ) {
+ if ( m_ItemCounter.value() >= capacity()) {
// the heap is full
m_Lock.unlock();
m_Stat.onPushFailed();
}
counter_type i = m_ItemCounter.inc();
- assert( i < m_Heap.capacity() );
+ assert( i < m_Heap.capacity());
node& refNode = m_Heap[i];
refNode.lock();
m_Lock.unlock();
+ assert( refNode.m_nTag == tag_type( Empty ));
+ assert( refNode.m_pVal == nullptr );
refNode.m_pVal = &val;
refNode.m_nTag = curId;
refNode.unlock();
- // Move item towards top of the heap while it has higher priority than parent
+ // Move item towards top of heap while it has a higher priority than its parent
heapify_after_push( i, curId );
m_Stat.onPushSuccess();
*/
value_type * pop()
{
+ node& refTop = m_Heap[1];
+
m_Lock.lock();
if ( m_ItemCounter.value() == 0 ) {
// the heap is empty
m_Stat.onPopFailed();
return nullptr;
}
- counter_type nBottom = m_ItemCounter.reversed_value();
- m_ItemCounter.dec();
- // Since m_Heap[0] is not used, capacity() returns m_Heap.capacity() - 1
- // Consequently, "<=" is here
- assert( nBottom <= capacity() );
+ counter_type nBottom = m_ItemCounter.dec();
+ assert( nBottom < m_Heap.capacity());
assert( nBottom > 0 );
- node& refBottom = m_Heap[ nBottom ];
+ refTop.lock();
+ if ( nBottom == 1 ) {
+ refTop.m_nTag = tag_type( Empty );
+ value_type * pVal = refTop.m_pVal;
+ refTop.m_pVal = nullptr;
+ refTop.unlock();
+ m_Lock.unlock();
+ m_Stat.onPopSuccess();
+ return pVal;
+ }
+
+ node& refBottom = m_Heap[nBottom];
refBottom.lock();
m_Lock.unlock();
refBottom.m_nTag = tag_type(Empty);
refBottom.m_pVal = nullptr;
refBottom.unlock();
- node& refTop = m_Heap[ 1 ];
- refTop.lock();
- if ( refTop.m_nTag == tag_type(Empty) ) {
+ if ( refTop.m_nTag == tag_type(Empty)) {
// nBottom == nTop
refTop.unlock();
m_Stat.onPopSuccess();
refTop.m_nTag = tag_type( Available );
// refTop will be unlocked inside heapify_after_pop
- heapify_after_pop( 1, &refTop );
+ heapify_after_pop( &refTop );
m_Stat.onPopSuccess();
return pVal;
template <typename Func>
void clear_with( Func f )
{
- while ( !empty() ) {
- value_type * pVal = pop();
- if ( pVal )
- f( *pVal );
- }
+ value_type * pVal;
+ while (( pVal = pop()) != nullptr )
+ f( *pVal );
}
/// Checks is the priority queue is empty
i = 0;
}
}
- else if ( refParent.m_nTag == tag_type( Empty ) ) {
+ else if ( refParent.m_nTag == tag_type( Empty )) {
m_Stat.onItemMovedTop();
i = 0;
}
}
}
- void heapify_after_pop( counter_type nParent, node * pParent )
+ void heapify_after_pop( node * pParent )
{
key_comparator cmp;
+ counter_type const nCapacity = m_Heap.capacity();
+
+ counter_type nParent = 1;
+ for ( counter_type nChild = nParent * 2; nChild < nCapacity; nChild *= 2 ) {
+ node* pChild = &m_Heap[ nChild ];
+ pChild->lock();
- while ( nParent < m_Heap.capacity() / 2 ) {
- counter_type nLeft = nParent * 2;
- counter_type nRight = nLeft + 1;
- node& refLeft = m_Heap[nLeft];
- node& refRight = m_Heap[nRight];
- refLeft.lock();
- refRight.lock();
-
- counter_type nChild;
- node * pChild;
- if ( refLeft.m_nTag == tag_type(Empty) ) {
- refRight.unlock();
- refLeft.unlock();
+ if ( pChild->m_nTag == tag_type( Empty )) {
+ pChild->unlock();
break;
}
- else if ( refRight.m_nTag == tag_type(Empty) || cmp( *refLeft.m_pVal, *refRight.m_pVal ) > 0 ) {
- refRight.unlock();
- nChild = nLeft;
- pChild = &refLeft;
- }
- else {
- refLeft.unlock();
- nChild = nRight;
- pChild = &refRight;
+
+ counter_type const nRight = nChild + 1;
+ if ( nRight < nCapacity ) {
+ node& refRight = m_Heap[nRight];
+ refRight.lock();
+
+ if ( refRight.m_nTag != tag_type( Empty ) && cmp( *refRight.m_pVal, *pChild->m_pVal ) > 0 ) {
+ // get right child
+ pChild->unlock();
+ nChild = nRight;
+ pChild = &refRight;
+ }
+ else
+ refRight.unlock();
}
- // If child has higher priority that parent then swap
+ // If child has higher priority than parent then swap
// Otherwise stop
if ( cmp( *pChild->m_pVal, *pParent->m_pVal ) > 0 ) {
std::swap( pParent->m_nTag, pChild->m_nTag );
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