Can't read file more than n bytes

[metaDom]

Hey guys,

I'm trying to parse a json file, however for some unknown reason it fails to read it completely. I can read 29276 bytes, then it suddenly stops. It doesn't matter if I try to save the content as QByteArray or QString. The qDebug() line is simply not executed, all code after works...

http://pastebin.com/raw/eQ9v0AyT

QFile dataFile("data.json");
if(dataFile.open(QIODevice::ReadOnly))
{
	QByteArray ba = dataFile.readAll();
	qDebug() << "File Content: " << ba;
	dataFile.close();
}

Any help is appreciated. Thanks in advance!

[m.sue]

Hi,
maybe qDebug() << ba; just doesn't show it all. Can you try qDebug() << ba.count();
-Michael.

[metaDom]

@m.sue dataFile.count() or dataFile.size() etc do work fine. What doesn't work is outputting the ba itself or stuff like ba.trimmed()

[m.sue]

Yes, but my point is about what it is that does not work: The reading itself or the output of the read-in bytearray via qDebug.
Please add the line:

qDebug() << ba.count();

-Michael.

[metaDom]

@m.sue sorry, typo. didn't mean dataFile.count(). "qDebug() << ba.count();" does work fine and give proper output.

When reading more than my limit, for example with "QByteArray ba = dataFile.read(29277)", ba.count() also does work. So yes, the reading works.

Adding the following returns "true". So the doc is also empty when using the ByteArray.

QJsonDocument doc = QJsonDocument::fromJson(ba);
                qDebug() << doc.isEmpty();

[m.sue]

That may be restriction in the buffer length of the (place where you view the) qDebug output.
Maybe just view it in two parts will show you the results:

qDebug() << ba.right(25000);
qDebug() << ba.mid(25000);    //+/- 1

[metaDom]

@m.sue said in Can't read file more than n bytes:

That may be restriction in the buffer length of the (place where you view the) qDebug output.
Maybe just view it in two parts will show you the results:

qDebug() << ba.right(25000);
qDebug() << ba.mid(25000);    //+/- 1

This actually works for output. I've used:

                qDebug() << "AAA";
                qDebug() << ba.left(dataFile.size()/2);
                qDebug() << "BBB";
                qDebug() << ba.right(dataFile.size()/2);
                qDebug() << "CCC";

Anyway, the buffer also seems to be there when doing:

QJsonDocument doc = QJsonDocument::fromJson(ba);

If I split the file, the json is invalid and can't be put with fromJson anymore. This seems to be a very weird limitation?!

[raspe88]

Have you tried the following steps to get a valid document:

1. Allocate a char-array of the size you need.
2. Copy the file-content using QTextStream to this array.
3. Get a valid QJsonDocument by using QJsonDocument::fromRawData

[jsulm]

@metaDom I think it is a limitation of qDebug: it just stops at some point to not to print too much. You can try to print with std::cout << ba;

[SGaist]

Hi,

Do you have any special character in your .json file ?