Binary file Reading.........

[umulingu]

Hai


I have a binary file I want to read that

either I have to use QBitArray or ByteArray ... DataStream

pl help me

[yogeshgokul]

If you want to access data bit by bit. For various binary operations. You should use QBitArray.
Otherwise QByteArray and QDataStream will work.

[umulingu]

Hai

that binary file in LittleEndian format

what to do?

pl give some example..

[yogeshgokul]

Hai
that binary file in LittleEndian format

The QDataStream class provides serialization of binary data to a QIODevice.
A data stream is a binary stream of encoded information which is 100% independent of the host computer's operating system, CPU or byte order

pl give some example..

QFile file("file.dat");
file.open(QIODevice::ReadOnly);
QDataStream in(&file);    // read the data serialized from the file
QString str;
qint32 a;
in >> str >> a;           // extract "the answer is" and 42

QFile file("file.dat");
file.open(QIODevice::ReadOnly);
QDataStream in(&file);    // read the data serialized from the file
QString str;
qint32 a;
in >> str >> a;           // extract "the answer is" and 42

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[umulingu]

hai

i tried with QDataStream and QByteArray. but the data is empty...

QFile fileA("/home/suresh/file1.lnd");
QByteArray buffer;
if(! fileA.open(QIODevice::ReadOnly))
{
QMessageBox::information(this,tr("Unable to Open"),fileA.errorString());
return;
}
buffer=fileA.readAll();
qDebug()<<buffer.data();
qDebug()<<buffer.size();

QFile fileA("/home/suresh/file1.lnd");
QByteArray buffer;
if(! fileA.open(QIODevice::ReadOnly))
{
QMessageBox::information(this,tr("Unable to Open"),fileA.errorString());
return;
}
buffer=fileA.readAll();
qDebug()<<buffer.data();
qDebug()<<buffer.size();

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output



206368

[nish]

dont use buffer.data() in qDebug... just use buffer... because a zero may terminate the char* at any point..

[yogeshgokul]

qDebug()<<buffer.data();
qDebug()<<buffer.size();


output
206368

The data is in the buffer, its just not printed by qDebug. You can write this buffer in another file and see. Both files should be identical.

[umulingu]

Hai
thanks for ur reply

actually that is binary file .
I want to read the data

how to get the datas?

[nish]

every binary file has a format... do you have the format (struct etc)..?

[umulingu]

yes I have that program and format

[nish]

then just go simple.. nad read the data as it was written in that program..

it must be written as
FILE* fp
fwrite(struct* ,fp);

so read it that way only..
FILE* fp
fread();...

[umulingu]

Thanks to all


I got solution.