import jdk.incubator.vector.*;

final sclass BWIntegralImage_vectorized implements MakesBufferedImage, IBWIntegralImage {

  int w, h;

  int vecShift; // vector size used as dual log

  int[] data; // 1 entry per pixel

  ifdef BWIntegralImage_CountAccesses

    long accesses;

  endifdef

  *() {}

  *(File f) { this(loadImage2(f)); }

  *(MakesBufferedImage img) { this(toBufferedImage(img)); }

  //*(BufferedImage img) { this(BWImage(img)); }

  *(BufferedImage image) ctex {

    alloc(image.getWidth(), image.getHeight());

    // Just grab directly into data array

    PixelGrabber pixelGrabber = new PixelGrabber(image, 0, 0, w, h, data, 0, w);

    if (!pixelGrabber.grabPixels())

      fail("Could not grab pixels");

    VectorSpecies<Int> species = IntVector.SPECIES_PREFERRED;

    vecShift = dualLog(species.length());

    int upperBound = species.loopBound(w);

    // for brightness of pixels,

    // for now we cheat by just using one of the channels

    // first row

    int i = 0, sum = 0;

    for (; i < upperBound; i += species.length()) {

      IntVector v = IntVector.fromArray(species, data, i);

      v = v.and(255).add(sum);

      v.intoArray(data, i);

      sum += v.reduceLanes(VectorOperators.ADD);

    }

    for (; i < w; i++)

      data[i] = (data[i] & 255) + sum;

    // subsequent rows

    int i = w;

    for (int y = 1; y < h; y++) {

      sum = 0;

      int x = 0;

      for (; x < upperBound; x += species.length(), i += species.length()) {

        IntVector v = IntVector.fromArray(species, data, i);

        IntVector v_last = IntVector.fromArray(species, data, i-w);

        v = v.and(255).add(v_last).add(sum);

        v.intoArray(data, i);

        sum += v.reduceLanes(VectorOperators.ADD);

      }

      for (; x < w; x++, i++)

        data[i] = (data[i] & 255) + sum;

    }

  }

  private void alloc(int w, int h) {

    this.w = w;

    this.h = h;

    if (w*h > 8*1024*1024)

      fail("Image too large (more than 8 MP): " + w + "*" + h);

    data = new int[w*h];

  }

  // pixels outside of image are considered black

  int get(int x, int y) {

    ifdef BWIntegralImage_CountAccesses

      ++accesses;

    endifdef

    ret x < 0 || y < 0 || x >= w || y >= h ? 0

      : data[min(y, h-1)*w+min(x, w-1)];

  }

  public double getPixelAverage(int x1, int y1, int x2, int y2) {

    int area = (x2-x1)*(y2-y1);

    ret doubleRatio(bwIntegralImage_sumRect(this, x1, y1, x2, y2), area);

  }

  int getPixel(int x, int y) {

    ret bwIntegralImage_sumRect(this, x, y, x+1, y+1);

  }

  int getPixel(Pt p) { ret getPixel(p.x, p.y); }

  public int getWidth() { ret w; }

  public int getHeight() { ret h; }

  // unoptimized

  public BufferedImage getBufferedImage() {

    ret scaleDownUsingIntegralImageBW(this, w).getBufferedImage();

  }

}