protected void filter()

in src/main/java/org/apache/pdfbox/jbig2/image/Scanline.java [392:447]
45 lines of code
14 McCabe index (conditional complexity)

        protected void filter(final int[] preShift, final int[] postShift, final Weighttab[] tabs,
                final Scanline dst)
        {
            final GenericRasterScanline grs = (GenericRasterScanline) dst;
            final int nx = dst.length;

            // start sum at 1<<shift-1 for rounding
            final int start[] = tmp;
            for (int c = 0; c < componentCount; c++)
                start[c] = 1 << postShift[c] - 1;

            final int l = data[0].length;

            // the next two blocks are duplicated except for the missing shift
            // operation if preShift==0.
            boolean hasPreShift = false;
            for (int c = 0; c < componentCount && !hasPreShift; c++)
                hasPreShift |= preShift[c] != 0;
            if (hasPreShift)
                for (int c = 0; c < componentCount; c++)
                {
                    final int ac[] = data[c];
                    final int bc[] = grs.data[c];
                    final int m = channelMask[c];
                    for (int b = 0; b < nx; b++)
                    {
                        final Weighttab wtab = tabs[b];
                        final int an = wtab.weights.length;

                        int sum = start[c];
                        for (int wp = 0, ap = wtab.i0; wp < an && ap < l; wp++, ap++)
                            sum += wtab.weights[wp] * (ac[ap] >> preShift[c]);

                        final int t = sum >> postShift[c];
                        bc[b] = t < 0 ? 0 : t > m ? m : t;
                    }
                }
            else
                for (int c = 0; c < componentCount; c++)
                {
                    final int ac[] = data[c];
                    final int bc[] = grs.data[c];

                    for (int b = 0; b < nx; b++)
                    {
                        final Weighttab wtab = tabs[b];
                        final int an = wtab.weights.length;

                        int sum = start[c];
                        for (int wp = 0, ap = wtab.i0; wp < an && ap < l; wp++, ap++)
                            sum += wtab.weights[wp] * ac[ap];

                        bc[b] = sum >> postShift[c];
                    }
                }
        }