Binary files and conversion

[timmu]

Thanks Wysota!

This following gives me all byte integer values but how do I get the individual bits out of it.
What I need is a continuous array of 0's and 1's.

void binarytobits()
{
int i, mybit;
 
QFile in("indata.dat");
 
if (!in.open(QIODevice::ReadOnly)) return;
 
 
QByteArray blob = in.readAll();
int size = blob.size();
 
 
for(i=0; i<size; i++)
{
mybit=blob.at(i); cout << mybit << "\n";
}
 
}

void binarytobits()
{
int i, mybit;

QFile in("indata.dat");

if (!in.open(QIODevice::ReadOnly)) return;


QByteArray blob = in.readAll();
int size = blob.size();


for(i=0; i<size; i++)
{
mybit=blob.at(i); cout << mybit << "\n";
}

}

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I wonder if this is a valid and good way to convert QByteArray to QBitArray

QByteArray blob = in.readAll();
QBitArray blob2=QVariant(blob2).toBitArray();

QByteArray blob = in.readAll();
QBitArray blob2=QVariant(blob2).toBitArray();

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[wysota]

This following gives me all byte integer values but how do I get the individual bits out of it.

Do you have ANY C/C++ knowledge? So far we are guiding you step by step and you don't seem to be making any effort yourself...

Use bit shifting or masking to extract specific bits from a byte value. This is a strictly C/C++ task, please try to solve it yourself.

[timmu]

Thanks!

Yes I do, I just don't know the bit operations. I was curious if Qt had something to that effect.

[wysota]

There is no need for Qt to have "something to that effect" if the programming language already provides it. There is no QAddTwoIntegers class in Qt the same way as there is no QInteger and no QIntegerAsBitString class. Even if there was no bit shifting in C, you should still be able to think your way through using regular integer divison.

[timmu]

I was wondering why the code below cannot read binary file and create a file with two columns:
showing the numerical value of each byte and then also its binary representation?

void binarytobits()
{
int i, size;
char mybyte;
 
QFile in("infile.dat"); if (!in.open(QIODevice::ReadOnly)) return;
QFile out("outfile.txt"); if (!out.open(QIODevice::WriteOnly)) return;
QTextStream out_stream(&out);
 
QByteArray blob = in.readAll();
size = blob.size();
 
for(i=0; i<size; i++)
{
mybyte=blob.at(i);
QString myBits( QString::number( mybyte, sizeof(&mybyte) ) );
out_stream << mybyte << " " << myBits <<"\n";
}
 
}

void binarytobits()
{
int i, size;
char mybyte;

QFile in("infile.dat"); if (!in.open(QIODevice::ReadOnly)) return;
QFile out("outfile.txt"); if (!out.open(QIODevice::WriteOnly)) return;
QTextStream out_stream(&out);

QByteArray blob = in.readAll();
size = blob.size();

for(i=0; i<size; i++)
{
mybyte=blob.at(i);
QString myBits( QString::number( mybyte, sizeof(&mybyte) ) );
out_stream << mybyte << " " << myBits <<"\n";
}

}

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[wysota]

Read the docs for QString::number().

Hint: sizeof(&mybyte) = sizeof(char*) = 4 (or 8)

[timmu]

Indeed sizeof(char*) is 4 in my case.

Are you suggesting that QString::number() is not appropriate for what I'm doing?

The code above is generating a binary file and I cannot open it with text editor. Why is it binary?

[wysota]

Are you suggesting that QString::number() is not appropriate for what I'm doing?

I'm suggesting you should read the documentation.

The code above is generating a binary file and I cannot open it with text editor. Why is it binary?

No idea. Text files are also binary files.