How to make QFile read the whole line

[JonB]

@ManiRon
OK, in that case it sounds right if it is followed by a "Nul". Personally I would put a comment into your code then to explain that is why you are seeking to byte #33.

I don't see anything which would stop at a NUL in your code. What makes you think it is doing so? Are you just relying on the output of qDebug("FILEDATA %s",fileData.data()); and thinking that shows it has not read past a NUL, that may be an artefact of how qDebug() displays the data? Try debugging out the length of the data?

[ManiRon]

@JonB Actually my requirement is to calculate checksum for the data and store it in the same file where the data i am writing to . So i planned to write the checksum at the begining and followed by the data.

Now when i start the application i will validate the file by reading the checksum stored in file and compare it with the remaining data in file by calculating checksum for them .

Note the stored checksum is calculated using the data and not the whole file

[VRonin]

could you replace fileData = file.read(size_of_file); with :

fileData.resize(size_of_file);
const auto actualRead = file.read(fileData.data(),size_of_file);
Q_ASSERT(actualRead==size_of_file);

[ManiRon]

@VRonin said in How to make QFile read the whole line:

actualRead

I tried sir but i am getting this kind of error

[jsulm]

@ManiRon It's not hard to fix:

const qint64 actualRead = file.read(fileData.data(),size_of_file);

[ManiRon]

@jsulm said in How to make QFile read the whole line:

const qint64 actualRead

error resolved

[ManiRon]

@VRonin but thsi doest read the full data

[ManiRon]

@JonB

No sir i checked the read by removing the NUL from the data in the file and i was able to see that it read the whole data and qDebug() was displaying the full data

This is the whole data when i removed the NUL : " WQA.,?E>t1?dWQA.,DE_??n1?d7be1526df618c0c4d1bab3959adb65ada9f20bd969493e532a7861d29bc6e698{TB.)?V1??n1?dS[H21?z7_??n1?d340819615bcd7cb87459cac37070456eb0af53716c1f0064c4771857728d3777 "

[ManiRon]

@ManiRon

But when the data conatins NUL the data will be " WQA.,?E>t1?dWQA.,DE_??n1?d7be1526df618c0c4d1bab3959adb65ada9f20bd969493e532a7861d29bc6e698 "

[jsulm]

@ManiRon said in How to make QFile read the whole line:

but thsi doest read the full data

What is the output of

qDebug() << actualRead << size_of_file;

?

[ManiRon]

@jsulm said in How to make QFile read the whole line:

size_of_file

Size = 194 .

I thought it was qdebug problem so i wrote the data read from the file to another file then also it remains the same as the data shown in the debug

[VRonin]

What is the value of actualRead?

[ManiRon]

@VRonin

Size = 194

[VRonin]

That means the read doesn't actually stop with the null

[ManiRon]

This post is deleted!

[ManiRon]

@VRonin

Yes you are right sir, So what can we do ?

[JonB]

@ManiRon
"What can we do" about what? You've spent the whole time claiming the read stops at the NUL, now you confirm it does not, so what's the problem?

[ManiRon]

@JonB

I am storing the data in QBytearray will that be a problem?

[ManiRon]

@JonB

the size it specifies is correct but the data displayed is till the NUL

[JonB]

@ManiRon said in How to make QFile read the whole line:

@JonB

the size it specifies is correct but the data displayed is till the NUL

But I said that was just how qDebug() displays data. Read up about how qDebug() displays strings/bytes, which may contain NUL.