QSettings write and read function

[ivareske]

When using ini files, does anyone know how QSettings transforms say a QStringList (or any other object) into the text that is written to the ini file? I am trying to encrypt the data before it is written. It would be great to just access the default read and write functions of qsettings, but I don`t find any info on these functions... Another possibility could be to tell QSettings to read/write using the standard functions to a QBuffer, then encrypt and then write to file. Doesn anyone know how to do this?

-Ivar

[wysota]

When using ini files, does anyone know how QSettings transforms say a QStringList (or any other object) into the text that is written to the ini file?

Qt is open-source. The easiest way is to look at the code responsible for this.

But since you want to do mangle the data I don't see the point in duplicating what QSettings does for ini files. Just provide your own read and write functions that save to a custom format and do the encryption as part of the process. The simplest possible read/write combination is:

bool readFile(QIODevice &device, QSettings::SettingsMap &map) {
    QDataStream stream(&device);
    device >> map;
    return true;
}
 
bool writeFile(QIODevice &device, const QSettings::SettingsMap &map) {
    QDataStream stream(&device);
    device << map;
    return true;
}

bool readFile(QIODevice &device, QSettings::SettingsMap &map) {
    QDataStream stream(&device);
    device >> map;
    return true;
}

bool writeFile(QIODevice &device, const QSettings::SettingsMap &map) {
    QDataStream stream(&device);
    device << map;
    return true;
}

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[ivareske]

Ok, but I still don`t understand how to convert my custom classes to QString. The map contains my custom object as a QVariant, how to I convert that to string so I can encrypt it?

[wysota]

I don't see your point. You can encrypt data regardless of the format it is in.

bool writeFile(QIODevice &device, const QSettings::SettingsMap &map) {
    QBuffer buffer;
    buffer.open(QIODevice::WriteOnly);
    QDataStream stream(&buffer);
    device << map;
    QByteArray encrypted = encrypt(buffer.data());
    device.write(encrypted);
    return true;
}

bool writeFile(QIODevice &device, const QSettings::SettingsMap &map) {
    QBuffer buffer;
    buffer.open(QIODevice::WriteOnly);
    QDataStream stream(&buffer);
    device << map;
    QByteArray encrypted = encrypt(buffer.data());
    device.write(encrypted);
    return true;
}

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