check_woffset
if ((r = check_woffset(buf, offset, 8, &p)) != 0)
if ((r = check_woffset(buf, offset, 4, &p)) != 0)
if ((r = check_woffset(buf, offset, 2, &p)) != 0)
if ((r = check_woffset(buf, offset, 1, &p)) != 0)
if ((r = check_woffset(buf, offset, len, &p)) != 0)