public boolean next() throws IOException {
   pointer++;
   if (pointer < docFreq) {
     in.seek(postingMaps[pointer].offset);
     freq = in.readVInt();
     position = 0;
     return true;
   }
   return false;
 }
 public int nextPosition() throws IOException {
   int positionIncrement = in.readVInt();
   position += positionIncrement;
   return position;
 }