changedOneline(buf_T *buf, linenr_T lnum)
{
    if (buf->b_mod_set)
    {
	// find the maximum area that must be redisplayed
	if (lnum < buf->b_mod_top)
	    buf->b_mod_top = lnum;
	else if (lnum >= buf->b_mod_bot)
	    buf->b_mod_bot = lnum + 1;
    }
    else
    {
	// set the area that must be redisplayed to one line
	buf->b_mod_set = TRUE;
	buf->b_mod_top = lnum;
	buf->b_mod_bot = lnum + 1;
	buf->b_mod_xlines = 0;
    }
}
changedOneline(buf_T *buf, linenr_T lnum)
{
    if (buf->b_mod_set)
    {
	 
	if (lnum < buf->b_mod_top)
	    buf->b_mod_top = lnum;
	else if (lnum >= buf->b_mod_bot)
	    buf->b_mod_bot = lnum + 1;
    }
    else
    {
	 
	buf->b_mod_set = TRUE;
	buf->b_mod_top = lnum;
	buf->b_mod_bot = lnum + 1;
	buf->b_mod_xlines = 0;
    }
}