QDataStream >>QByteArray [was QByteArray resize not working?!]

[pdoria]

Well ... it's an array of bytes of arbitrary binary content...

funny thing the compiler is perfectly happy with QDataStream >> QByteArray...
Why does it fail the call is still beyond me... (and this is exactly the kind of thing that gets you stuck for hours on end )

To be honest, and never forgetting my place (newbie), I'd call this one a bug on QT4.
This call should fetch myQByteArray.size bytes from the stream, regardless of content.
Reading the docs for QByteArray it's stated "QByteArray can be used to store both raw bytes..." so it shouldn't matter what kind of content, or where it came from, one puts in it...


Bottom line: is there no other (optimized) way than being stuck with this?

qint8 c;
 for (int i = 0; i < sPacket.size_app_payload; i++) {
records >> c;
sPacket.app_payload[i] = c;
}

qint8 c;
 for (int i = 0; i < sPacket.size_app_payload; i++) {
records >> c;
sPacket.app_payload[i] = c;
}

To copy to clipboard, switch view to plain text mode 

Regarding my other difficulty ...
I want to extract the first two bytes from it to a quint16

Could you please show me a way?

TIA,
Pedro.

[wysota]

Well ... it's an array of bytes of arbitrary binary content...

So it won't work.

funny thing the compiler is perfectly happy with QDataStream >> QByteArray...

Because this is syntactically correct.

Why does it fail the call is still beyond me... (and this is exactly the kind of thing that gets you stuck for hours on end )

Then read the first sentence of QDataStream documentation and then use QIODevice::read() on the socket directly.

To be honest, and never forgetting my place (newbie), I'd call this one a bug on QT4.

It's not a bug, it's a misunderstanding of what QDataStream is.

This call should fetch myQByteArray.size bytes from the stream, regardless of content.

No. Make the following experiment:

QFile f("test.bin");
f.open(QFile::WriteOnly);
QDataStream dstream(&f);
dstream << 7;
f.close();

QFile f("test.bin");
f.open(QFile::WriteOnly);
QDataStream dstream(&f);
dstream << 7;
f.close();

To copy to clipboard, switch view to plain text mode 

Now go and take a look at size of the created file and its content and everything will become clear.