protected void filter()

in src/main/java/org/apache/pdfbox/jbig2/image/Scanline.java [531:575]

• 36 lines of code
• 9 McCabe index (conditional complexity)

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

            // start sum at 1<<shift-1 for rounding
            final int start = 1 << postShift[0] - 1;
            final int abuf[] = data;
            final int bbuf[] = bblps.data;

            // the next two blocks are duplicated except for the missing shift
            // operation if preShift==0.
            final int preShift0 = preShift[0];
            final int postShift0 = postShift[0];
            if (preShift0 != 0)
                for (int bp = 0, b = 0; b < nx; b++)
                {
                    final Weighttab wtab = tabs[b];
                    final int an = wtab.weights.length;

                    int sum = start;
                    for (int wp = 0, ap = wtab.i0; wp < an && ap < abuf.length; wp++)
                    {
                        sum += wtab.weights[wp] * (abuf[ap++] >> preShift0);
                    }

                    final int t = sum >> postShift0;
                    bbuf[bp++] = t < 0 ? 0 : t > 255 ? 255 : t;
                }
            else
                for (int bp = 0, b = 0; b < nx; b++)
                {
                    final Weighttab wtab = tabs[b];
                    final int an = wtab.weights.length;

                    int sum = start;
                    for (int wp = 0, ap = wtab.i0; wp < an && ap < abuf.length; wp++)
                    {
                        sum += wtab.weights[wp] * abuf[ap++];
                    }

                    bbuf[bp++] = sum >> postShift0;
                }
        }