qprogressbar without knowing the time

In post QProgress Bar-Time Measuring is used a known time. How do I do if I do not know the time?
I have a program that read a file with many lines. This program takes the first line and test whether it is equal to some other line of the file. Take the next does the same thing to the end. But the program hangs and only responds when you finish the test.
I would like a QProgressBar controlling it. But I have no idea.
Someone help me? Thanks.

Code:

---

while (!in.atEnd()) {
                    novo:
                    line = in.readLine();
                    next = in.pos();
                    test.clear();
 
                    test = line.split(QRegExp("\\s+"));
                    zero = test[2].toFloat(&ok);
                    zero2 = test[3].toFloat(&ok2);
 
                    if(!ok || !ok2 || zero == 0.0 || zero2 == 0.0 || test.size() <= 3){
 
                        if(in.atEnd()){
                            continue;
                        }else {
                            goto novo;
                        }
                    }else {
 
                        junto = test[2] + test[3];
 
                        while (!in.atEnd()) {
                            line = in.readLine();
                            comp.clear();
                            comp = line.split(QRegExp("\\s+"));
                            zero = comp[2].toFloat(&ok);
                            zero2 = comp[3].toFloat(&ok2);
 
                            if (!ok || !ok2 || zero == 0.0 || zero2 == 0.0 || comp.size() <= 3){
                                //relout << comp.size() << "Comp " << comp[3] << endl;
                                if (varrer.atEnd())
                                    break;
                                else
                                    continue;
                            }else if (junto == comp[2]+comp[3]){
                                relout << "Equal: Line " << comp[2] << " PT " << comp[3] << endl;
                                file.close();
                                break;
                                //return;
                            }
                        }
                        in.seek(next);
                  }
}

---

You could try increasing the bar inside the loop where you read the file contents.
When it reaches 100 reduce it by say 20, and continue.

Once out of the loop, set it to 100

But that does not solve the lock of the window. The file contains 4500 lines. During the process the program tests if any line is equal. This generates a lot of information and just locking the widget parent.
I tried to use, but did not worked.

Code:

---

int i = 0;
while (!xx.atEnd()) {
++i;
if ((i % 100) == 0) {
QCoreApplication::processEvents();
}
// processes which need to be processed.
}

---

any ideas?

Problem solved. I used QProgressDialog :p