QDataStream read from a specific sequence

beecksche

Hi,
i save some informations as binary data into a file. I serialize the data with the QDataStream class.

QFile file("export.dat");
file.open();

QDataStream stream(&file);
stream << QString("Header1");
stream << m_value1 << m_value2;

stream << QString("Header2");
stream << m_value3 << m_value4;

file.close();

And read it with:

QFile file("export.dat");
file.open();

QDataStream stream(&file);
QString header1;
stream >> header1;

double m_value1, m_value2;
stream >> m_value1 >> m_value2;

QString header2;
stream >> header2;

double m_value3, m_value4;
stream >> m_value3 >>m_value4;

file.close();

I search a way just to read the values after Header2. Is there a way like

QFile file("export.dat");
file.open();

QDataStream stream(&file);

bool ok = stream.readFrom(QString("Header2"));
double m_value3, m_value4;
stream >> m_value3 >>m_value4;

Or do just need to read the file as byte array and search for the Header2 sequence?

Thanks for any advice.

Edit:

My solution:

QFile file("export.dat");
file.open();

QByteArray bytes = file.readAll();

QByteArray headerAsBytes;
QDataStream headerStream(&headerAsBytes, QIODevice::WriteOnly);
headerStream << QString("Header2");
int startIndex = bytes.indexOf(headerAsBytes);

QDataStream stream(&bytes, QIODevice::ReadOnly);
stream.skipRawData(startIndex);

QString header2;
stream >> header2;

double m_value3, m_value4;
stream >> m_value3 >>m_value4;

The section where the header2 - QString is converted as QByteArray is really ugly, but it works for me.