reset() of Reader in zxing - android

Question

I'm looking the zxing repository at GitHub for hours. The BenchmarkAsyncTask of androidtest walk throught a file path and continuously decode some image files wihout call reset() of the reader.

But in the comment of Reader.reset, it says that

Resets any internal state the implementation has after a decode, to prepare it for reuse.

Since we reused the multiFormatReader, should do not we call the reset()?

Answer 1

If you debug the ZXing source code step by step, you will see that reset() does nothing for all readers except RSS14Reader and RSSExpandedReader.

Do nothing:

@Override
  public void reset() {
    // do nothing
  }

RSS14Reader.reset():

@Override
  public void reset() {
    possibleLeftPairs.clear();
    possibleRightPairs.clear();
  }

RSSExpandedReader.reset()

@Override
  public void reset() {
    this.pairs.clear();
    this.rows.clear();
  }

If you just want to read QR code, there's no difference. For example:

String[] fileNames = new String[]{"qrcode-1.jpg", "qrcode-2.jpg"};
File file = null;
BufferedImage image = null;
RGBLuminanceSource source = null;
BinaryBitmap bitmap = null;
Result result = null;
MultiFormatReader reader = new MultiFormatReader();

try {
    for (String fileName : fileNames) {
        file = new File(fileName);
        image = ImageIO.read(file);
        System.out.println(image.getWidth() + ", " + image.getHeight());
        int[] pixels = image.getRGB(0, 0, image.getWidth(), image.getHeight(), null, 0, image.getWidth());
        source = new RGBLuminanceSource(image.getWidth(), image.getHeight(), pixels);
        bitmap = new BinaryBitmap(new HybridBinarizer(source));
        result = reader.decode(bitmap);
        System.out.println(result.getText());
        //reader.reset();
    }
}
catch (Exception exception) {
    System.out.println(exception);
}