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

src/PriorityQueue.h

@@ -0,0 +1,99 @@
+// $Id: PriorityQueue.h 6219 2008-10-01 05:39:07Z vern $
+//
+// See the file "COPYING" in the main distribution directory for copyright.
+
+#ifndef __PriorityQueue__
+#define __PriorityQueue__
+
+#include <math.h>
+
+class PriorityQueue;
+
+class PQ_Element {
+public:
+	PQ_Element(double t)	{ time = t; offset = -1; }
+	virtual ~PQ_Element()	{ }
+
+	double Time() const	{ return time; }
+
+	int Offset() const	{ return offset; }
+	void SetOffset(int off)	{ offset = off; }
+
+	void MinimizeTime()	{ time = -HUGE_VAL; }
+
+protected:
+	PQ_Element()		{ }
+	double time;
+	int offset;
+};
+
+class PriorityQueue {
+public:
+	PriorityQueue(int initial_size = 16);
+	~PriorityQueue();
+
+	// Returns the top of queue, or nil if the queue is empty.
+	PQ_Element* Top() const
+		{
+		if ( heap_size == 0 )
+			return 0;
+		else
+			return heap[0];
+		}
+
+	// Removes (and returns) top of queue.  Returns nil if the queue
+	// is empty.
+	PQ_Element* Remove();
+
+	// Removes element e.  Returns e, or nil if e wasn't in the queue.
+	// Note that e will be modified via MinimizeTime().
+	PQ_Element* Remove(PQ_Element* e);
+
+	// Add a new element to the queue.  Returns 0 on failure (not enough
+	// memory to add the element), 1 on success.
+	int Add(PQ_Element* e);
+
+	int Size() const	{ return heap_size; }
+	int PeakSize() const	{ return peak_heap_size; }
+
+protected:
+	int Resize(int new_size);
+
+	void BubbleUp(int bin);
+	void BubbleDown(int bin);
+
+	int Parent(int bin) const
+		{
+		return bin >> 1;
+		}
+
+	int LeftChild(int bin) const
+		{
+		return bin << 1;
+		}
+
+	int RightChild(int bin) const
+		{
+		return LeftChild(bin) + 1;
+		}
+
+	void SetElement(int bin, PQ_Element* e)
+		{
+		heap[bin] = e;
+		e->SetOffset(bin);
+		}
+
+	void Swap(int bin1, int bin2)
+		{
+		PQ_Element* t = heap[bin1];
+		SetElement(bin1, heap[bin2]);
+		SetElement(bin2, t);
+		}
+
+	PQ_Element** heap;
+	int heap_size;
+	int peak_heap_size;
+	int max_heap_size;
+};
+
+#endif