Parsing a qbytearray from a binary file

Question

Im trying to read around 3000 binary files each binary file is written in little endian. I seek to the file offset and read the entire buffer into a qbytearray.

The binary format is int32 stringlength; (4 bytes) string stringname; + 'null'

File example:

//09 00 00 00 63 6f 6e 76 65 72 74 65 72 00 05 00 00 00 63 6f 75 6e 74 00
// 9 is the size then string.. then size then string..

QFile file("papers.bin");
if (!file.open(QIODevice::ReadOnly))
    return;

file.seek(file.size() - 266 );

QByteArray binarydata = file.readall();

//09 00 00 00 63 6f 6e 76 65 72 74 65 72 00 05 00 00 00 63 6f 75 6e 74

//loop data

How would i loop the data inside the qbytearray?

Answer 1

Use a QDataStream to read chunks:

QDataStream stream(binarydata);
stream.setByteOrder(QDataStream::LittleEndian);
while (!stream.atEnd()) {
    qint32 length;
    stream >> length;

    QByteArray buf(length, 0);
    stream.readRawData(buf.data(), length);
    QString str = QString::fromUtf8(buf);
    // do something with str

    stream.skipRawData(1); // Skip the 00 byte
}