code: public void readFrom(java.io.InputStream is) throws IOException {
          int howmuch = 0;
          do {
              _write_pos += howmuch;
              moveWindow(_write_pos);
              howmuch = is.read(_memory_buffer);
          } while (howmuch != -1);
      }
docs: Reads all available data from input stream.
  @param is
  @throws IOException