public int align(int alignValue) {
        long align = currentIndex % alignValue;
        if (align == 0) {
            return 0;
        }
        currentIndex = currentIndex + (alignValue - align);
        return (int)(alignValue - align);
    }
Aligns the current index on the specified alignment value.
For example, if current index was 123 and align value was
16, then current index would become 128.
@param alignValue
@return the number of bytes required to align
GPL/DMG/src/dmg/java/mobiledevices/dmg/ghidra/GBinaryReader.java