    bool isExvType(BasicIo& iIo, bool advance)
    {
        bool result = true;
        byte tmpBuf[7];
        iIo.read(tmpBuf, 7);
        if (iIo.error() || iIo.eof()) return false;

        if (   0xff != tmpBuf[0] || 0x01 != tmpBuf[1]
            || memcmp(tmpBuf + 2, ExvImage::exiv2Id_, 5) != 0) {
            result = false;
        }
        if (!advance || !result) iIo.seek(-7, BasicIo::cur);
        return result;
    }
Unknown