QT5 QByteArray Struct convert

To convert a `QByteArray` to a `struct`, you can use a combination of `QDataStream` and `memcpy`.

First, define your `struct` with the desired fields and their types. For example:

struct MyStruct {
    int id;
    QByteArray name;
    double value;
};

Then, to convert a `QByteArray` to this `struct`, you can use the following code:

QByteArray byteArray = ... // your QByteArray
MyStruct myStruct;

QDataStream stream(&byteArray, QIODevice::ReadOnly);
stream.readRawData((char*) &myStruct.id, sizeof(myStruct.id));
stream >> myStruct.name;
stream.readRawData((char*) &myStruct.value, sizeof(myStruct.value));

This reads each field from the `QByteArray` using `QDataStream`, and uses `memcpy` to copy the data into the corresponding field in the `struct`.

Similarly, to convert a `struct` to a `QByteArray`, you can use the following code:

MyStruct myStruct = ... // your struct
QByteArray byteArray;

QDataStream stream(&byteArray, QIODevice::WriteOnly);
stream.writeRawData((char*) &myStruct.id, sizeof(myStruct.id));
stream << myStruct.name;
stream.writeRawData((char*) &myStruct.value, sizeof(myStruct.value));

This writes each field of the `struct` to the `QByteArray` using `QDataStream`, and the resulting `QByteArray` can be sent or stored as needed.