How can i evit when i use this code:

Qt Code: 
  1. QByteArray buffer;
  2.     QByteArray newBuffer;
  3.  
  4.     QFile file("Test.rar");
  5.     file.open(QIODevice::ReadOnly);
  6.     buffer = file.readAll();
  7.     file.close();
  8.  
  9.     QFile temp("temp");
  10.     temp.open(QIODevice::WriteOnly);
  11.  
  12.     QTextStream out(&temp);
  13.     out << buffer;
  14.     temp.close();
  15.  
  16.     temp.open(QIODevice::ReadOnly);
  17.     newBuffer = temp.readAll();
  18.  
  19.     QFile fileOut("TestOut.rar");
  20.     fileOut.open(QIODevice::WriteOnly);
  21.     fileOut.write(newBuffer);
  22.     fileOut.close();
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that some characters of the original QByteArray when i use QTextStream are replace with "?"

Look, Like This

?it?? = with QTextStream
˜it€€ = without passing to QTextSteam

How can i evit this replacing of unkwown charcaters