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How to make QFile read the whole line

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  • VRoninV 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);
    
    ManiRonM Offline
    ManiRonM Offline
    ManiRon
    wrote on last edited by
    #14

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

    actualRead

    1_1542281674674_Untitled2.jpg 0_1542281674660_Untitled1.jpg

    I tried sir but i am getting this kind of error

    jsulmJ 1 Reply Last reply
    0
    • ManiRonM ManiRon

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

      actualRead

      1_1542281674674_Untitled2.jpg 0_1542281674660_Untitled1.jpg

      I tried sir but i am getting this kind of error

      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #15

      @ManiRon It's not hard to fix:

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

      https://forum.qt.io/topic/113070/qt-code-of-conduct

      ManiRonM 1 Reply Last reply
      1
      • jsulmJ jsulm

        @ManiRon It's not hard to fix:

        const qint64 actualRead = file.read(fileData.data(),size_of_file);
        
        ManiRonM Offline
        ManiRonM Offline
        ManiRon
        wrote on last edited by
        #16

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

        const qint64 actualRead

        error resolved

        1 Reply Last reply
        0
        • VRoninV 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);
          
          ManiRonM Offline
          ManiRonM Offline
          ManiRon
          wrote on last edited by
          #17

          @VRonin but thsi doest read the full data

          jsulmJ 1 Reply Last reply
          0
          • JonBJ 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?

            ManiRonM Offline
            ManiRonM Offline
            ManiRon
            wrote on last edited by ManiRon
            #18

            @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 "

            ManiRonM 1 Reply Last reply
            0
            • ManiRonM 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 "

              ManiRonM Offline
              ManiRonM Offline
              ManiRon
              wrote on last edited by
              #19

              @ManiRon

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

              1 Reply Last reply
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              • ManiRonM ManiRon

                @VRonin but thsi doest read the full data

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #20

                @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;
                

                ?

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                ManiRonM 1 Reply Last reply
                0
                • jsulmJ 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;
                  

                  ?

                  ManiRonM Offline
                  ManiRonM Offline
                  ManiRon
                  wrote on last edited by ManiRon
                  #21

                  @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

                  ManiRonM 1 Reply Last reply
                  0
                  • VRoninV Offline
                    VRoninV Offline
                    VRonin
                    wrote on last edited by
                    #22

                    What is the value of actualRead?

                    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                    ~Napoleon Bonaparte

                    On a crusade to banish setIndexWidget() from the holy land of Qt

                    ManiRonM 1 Reply Last reply
                    1
                    • VRoninV VRonin

                      What is the value of actualRead?

                      ManiRonM Offline
                      ManiRonM Offline
                      ManiRon
                      wrote on last edited by
                      #23

                      @VRonin

                      Size = 194

                      1 Reply Last reply
                      0
                      • VRoninV Offline
                        VRoninV Offline
                        VRonin
                        wrote on last edited by
                        #24

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

                        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                        ~Napoleon Bonaparte

                        On a crusade to banish setIndexWidget() from the holy land of Qt

                        ManiRonM 1 Reply Last reply
                        1
                        • ManiRonM 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

                          ManiRonM Offline
                          ManiRonM Offline
                          ManiRon
                          wrote on last edited by
                          #25
                          This post is deleted!
                          1 Reply Last reply
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                          • VRoninV VRonin

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

                            ManiRonM Offline
                            ManiRonM Offline
                            ManiRon
                            wrote on last edited by ManiRon
                            #26

                            @VRonin

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

                            JonBJ 1 Reply Last reply
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                            • ManiRonM ManiRon

                              @VRonin

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

                              JonBJ Online
                              JonBJ Online
                              JonB
                              wrote on last edited by JonB
                              #27

                              @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?

                              ManiRonM 2 Replies Last reply
                              1
                              • JonBJ 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?

                                ManiRonM Offline
                                ManiRonM Offline
                                ManiRon
                                wrote on last edited by
                                #28

                                @JonB

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

                                1 Reply Last reply
                                0
                                • JonBJ 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?

                                  ManiRonM Offline
                                  ManiRonM Offline
                                  ManiRon
                                  wrote on last edited by
                                  #29

                                  @JonB

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

                                  JonBJ 1 Reply Last reply
                                  0
                                  • ManiRonM ManiRon

                                    @JonB

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

                                    JonBJ Online
                                    JonBJ Online
                                    JonB
                                    wrote on last edited by
                                    #30

                                    @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.

                                    ManiRonM 1 Reply Last reply
                                    0
                                    • JonBJ 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.

                                      ManiRonM Offline
                                      ManiRonM Offline
                                      ManiRon
                                      wrote on last edited by
                                      #31

                                      @JonB

                                      I have doubt in storing the data i store the data read in QBytearray

                                      JonBJ 1 Reply Last reply
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                                      • ManiRonM ManiRon

                                        @JonB

                                        I have doubt in storing the data i store the data read in QBytearray

                                        JonBJ Online
                                        JonBJ Online
                                        JonB
                                        wrote on last edited by
                                        #32

                                        @ManiRon
                                        So read up how qDebug() displays a QByteArray (as well as a QString)!!
                                        Something even as old as https://www.qtcentre.org/threads/54236-qDebug-donsn-t-display-0x00?p=243053#post243053 will presumably do you.....

                                        ManiRonM 1 Reply Last reply
                                        2
                                        • JonBJ JonB

                                          @ManiRon
                                          So read up how qDebug() displays a QByteArray (as well as a QString)!!
                                          Something even as old as https://www.qtcentre.org/threads/54236-qDebug-donsn-t-display-0x00?p=243053#post243053 will presumably do you.....

                                          ManiRonM Offline
                                          ManiRonM Offline
                                          ManiRon
                                          wrote on last edited by ManiRon
                                          #33

                                          @JonB

                                          Yes sir i can understand that it will take NUL as a terminate . Is there any way that i can store the full data along with the NUL

                                          Christian EhrlicherC 1 Reply Last reply
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