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  1. #1
    Join Date
    Apr 2009
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    Qt products
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    Windows

    Default Reading and writing bytes in file

    I am attempting to read the bytes from one file, compress them, stick them in another file, and read that file back in at a later time to get those bytes. But the bytes I write don't seem to be the same bytes I read back in and they should be. I tried computing a checksum to verify but the problem I see is that checksumBefore does not equal checksumAfter (see below). What am I missing?

    Qt Code:
    1. QList<QByteArray> _compressedArrayList;
    2.  
    3. QFile file1( "foo.xml" );
    4. file1.open( QFile::ReadOnly );
    5. QByteArray fileBytes = file1.readAll();
    6. QByteArray compressedFileBytes = qCompress( fileBytes );
    7. quint16 checksumBefore = qChecksum( compressedFileBytes.data(), compressedFileBytes.count() );
    8. _compressedArrayList << compressedFileBytes;
    9. file1.close();
    10.  
    11. QFile file( "out" );
    12. if( file.open( QIODevice::WriteOnly | QIODevice::Truncate ) )
    13. {
    14. QDataStream fout( &file );
    15. foreach( QByteArray byteArray, _compressedArrayList )
    16. {
    17. fout << byteArray.data();
    18. }
    19. file.close();
    20. }
    21.  
    22. //..............
    23. //..............
    24. QFile packageFile( "out" );
    25. packageFile.open( QFile::ReadOnly );
    26. QByteArray compressedFileBytes = packageFile.read( compressedFileBytes.count() );
    27. quint16 checksumAfter = qChecksum( compressedFileBytes.data(), compressedFileBytes.count() );
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    Last edited by DiamonDogX; 20th May 2009 at 18:42.

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