QDatastream read raw data

[saitej]

I have used QDatastream to write Qbytearray to a file using writerawdata().

I tried reading this same file using QDatastream. I wanted to use readrawdata() but I dont know its length. So what is the other way to read the data again in to a qbytearray?

[kuzulis]

There are two ways:

1. Just use << / >> with QByteArray directly:

QByteArray to = ...
out << to;

QByteArray from;
in >> from;

2. Or use writerawdata/readrawdata and store the array size, like:

QByteArray to = ...
out << qint64(to.size());
out.writerawdata(..., size);

QByteArray from;
qint64 size = 0;
in >> size;
in.readrawdata(..., size);

PS: I prefer the first way, if there no any restrictions/requirements for the file format.