from a QIndex (row/column coordinate system), get the buffer index of the byte

def qindex2index(index):
        """ from a QIndex (row/column coordinate system), get the buffer index of the byte """
        r = index.row()
        c = index.column()
        if c > 0x10:
            return (0x10 * r) + c - 0x11
        else:
            return (0x10 * r) + c