Heap<HeapEntry> heap = new SequentialHeap<HeapEntry>(occurrences, true);
for(int i=0; i<frequency.length; i++){
if(frequency[i]>0){
heap.add(new HeapEntry(frequency[i], new LeafNode(min+i)));
}
}
if(this.current<HuffmanOutputStream.blocksize){
// consider also EOF!