Initial import of svn+ssh:://svn.icir.org/bro/trunk/bro as of r7088

src/PriorityQueue.cc

@@ -0,0 +1,138 @@
+// $Id: PriorityQueue.cc 6219 2008-10-01 05:39:07Z vern $
+//
+// See the file "COPYING" in the main distribution directory for copyright.
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "PriorityQueue.h"
+#include "util.h"
+
+PriorityQueue::PriorityQueue(int initial_size)
+	{
+	max_heap_size = initial_size;
+	heap = new PQ_Element*[max_heap_size];
+	peak_heap_size = heap_size = 0;
+	}
+
+PriorityQueue::~PriorityQueue()
+	{
+	for ( int i = 0; i < heap_size; ++i )
+		delete heap[i];
+
+	delete [] heap;
+	}
+
+PQ_Element* PriorityQueue::Remove()
+	{
+	if ( heap_size == 0 )
+		return 0;
+
+	PQ_Element* top = heap[0];
+
+	--heap_size;
+	SetElement(0, heap[heap_size]);
+	BubbleDown(0);
+
+	top->SetOffset(-1);	// = not in heap
+	return top;
+	}
+
+PQ_Element* PriorityQueue::Remove(PQ_Element* e)
+	{
+	if ( e->Offset() < 0 || e->Offset() >= heap_size ||
+	     heap[e->Offset()] != e )
+		return 0;	// not in heap
+
+	e->MinimizeTime();
+	BubbleUp(e->Offset());
+
+	PQ_Element* e2 = Remove();
+
+	if ( e != e2 )
+		internal_error("inconsistency in PriorityQueue::Remove");
+
+	return e2;
+	}
+
+int PriorityQueue::Add(PQ_Element* e)
+	{
+	SetElement(heap_size, e);
+
+	BubbleUp(heap_size);
+
+	if ( ++heap_size > peak_heap_size )
+		peak_heap_size = heap_size;
+
+	if ( heap_size >= max_heap_size )
+		return Resize(max_heap_size * 2);
+	else
+		return 1;
+	}
+
+int PriorityQueue::Resize(int new_size)
+	{
+	PQ_Element** tmp = new PQ_Element*[new_size];
+	for ( int i = 0; i < max_heap_size; ++i )
+		tmp[i] = heap[i];
+
+	delete [] heap;
+	heap = tmp;
+
+	max_heap_size = new_size;
+
+	return heap != 0;
+	}
+
+void PriorityQueue::BubbleUp(int bin)
+	{
+	if ( bin == 0 )
+		return;
+
+	int p = Parent(bin);
+	if ( heap[p]->Time() > heap[bin]->Time() )
+		{
+		Swap(p, bin);
+		BubbleUp(p);
+		}
+	}
+
+void PriorityQueue::BubbleDown(int bin)
+	{
+	double v = heap[bin]->Time();
+
+	int l = LeftChild(bin);
+	int r = RightChild(bin);
+
+	if ( l >= heap_size )
+		return;		// No children.
+
+	if ( r >= heap_size )
+		{ // Just a left child.
+		if ( heap[l]->Time() < v )
+			Swap(l, bin);
+		}
+
+	else
+		{
+		double lv = heap[l]->Time();
+		double rv = heap[r]->Time();
+
+		if ( lv < rv )
+			{
+			if ( lv < v )
+				{
+				Swap(l, bin);
+				BubbleDown(l);
+				}
+			}
+
+		else if ( rv < v )
+			{
+			Swap(r, bin);
+			BubbleDown(r);
+			}
+		}
+	}