code: @Override
      public long position() throws IOException
      {
          if (inflater == null && deflater == null)
          {
              return 0;
          }
          if (inflater != null)
          {
              return inflater.getBytesWritten();
          }
          else
          {
              return deflater.getBytesRead();
          }
      }
docs: return uncompressed position
  @return
  @throws IOException