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std::string to QString can't convert properly

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  • Ketan__Patel__0011K Ketan__Patel__0011

    @JonB

    Yes i was read about windows / codecs / qDebug() / QTextEdit
    And you misunderstood about my reply

    and If i used this way

             qDebug() << QString::fromLocal8Bit (Data.c_str()) << endl;  
    

    Then i get most of data but i did't get all character same as std::string

    JonBJ Offline
    JonBJ Offline
    JonB
    wrote on last edited by JonB
    #8

    @Ketan__Patel__0011
    But @Bonnie already told you:

    But some characters cannot be printed by QDebug (I don't know why).

    (which is true), and he said:

    You can show the text in a text edit or something else, and you'll see the result is right.

    ui->textEdit->setPlainText(QString::fromStdString (Data));
    

    So why try qDebug() output again, when he has made this suggestion for you to at least give a go?

    but i did't get all character same as std::string

    If that's really the case once you have tried QTextEdit, then check what the length is of the std::string vs that of the converted QString.

    Ketan__Patel__0011K 1 Reply Last reply
    1
    • JonBJ JonB

      @Ketan__Patel__0011
      But @Bonnie already told you:

      But some characters cannot be printed by QDebug (I don't know why).

      (which is true), and he said:

      You can show the text in a text edit or something else, and you'll see the result is right.

      ui->textEdit->setPlainText(QString::fromStdString (Data));
      

      So why try qDebug() output again, when he has made this suggestion for you to at least give a go?

      but i did't get all character same as std::string

      If that's really the case once you have tried QTextEdit, then check what the length is of the std::string vs that of the converted QString.

      Ketan__Patel__0011K Offline
      Ketan__Patel__0011K Offline
      Ketan__Patel__0011
      wrote on last edited by
      #9

      @JonB

      i am use this line in my code

                   ui->textEdit->setPlainText(QString::fromStdString(Data));
      

      and you can see output

      12.PNG

      and my actual string data string is :

           std::string  Data = "Z¾xÞ?î?é?ðuفçzá?æ?ö?èæYÆV½MÃT¾T¿M³";
      
      1 Reply Last reply
      0
      • Christian EhrlicherC Online
        Christian EhrlicherC Online
        Christian Ehrlicher
        Lifetime Qt Champion
        wrote on last edited by
        #10

        @Ketan__Patel__0011 said in std::string to QString can't convert properly:

        and my actual string data string is :

        again: which encoding is this string?

        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
        Visit the Qt Academy at https://academy.qt.io/catalog

        Ketan__Patel__0011K 1 Reply Last reply
        1
        • Christian EhrlicherC Christian Ehrlicher

          @Ketan__Patel__0011 said in std::string to QString can't convert properly:

          and my actual string data string is :

          again: which encoding is this string?

          Ketan__Patel__0011K Offline
          Ketan__Patel__0011K Offline
          Ketan__Patel__0011
          wrote on last edited by
          #11

          @Christian-Ehrlicher

          i generate this string using my encryption algorithm and i am using some high logic for it

          Like Multiple Looping Statements And Leader Conditions

          B JonBJ 2 Replies Last reply
          0
          • Ketan__Patel__0011K Ketan__Patel__0011

            @Christian-Ehrlicher

            i generate this string using my encryption algorithm and i am using some high logic for it

            Like Multiple Looping Statements And Leader Conditions

            B Offline
            B Offline
            Bonnie
            wrote on last edited by Bonnie
            #12

            @Ketan__Patel__0011 I think maybe your cpp file is not saved in UTF8...
            But never mind, since the string is just an output of encryption algorithm...There'll be characters that even UTF8 cannot handle.
            You should know that we usually don't save that kind of string (or we should call it raw data) directly, because it is not readable / printable.
            We encode the raw data to hex / base64 string, and use that to save / transfer to others.
            And when we need the raw data, we decode from that hex / base64 string.
            If you don't want to save / transfer / make it readable, just want to get rid of a std::string and use Qt's class to store it, then you should use QByteArray instead of QString.
            So there won't be any option about "what codec should be used to convert the string" since it is not a really string!

            1 Reply Last reply
            1
            • Ketan__Patel__0011K Ketan__Patel__0011

              @Christian-Ehrlicher

              i generate this string using my encryption algorithm and i am using some high logic for it

              Like Multiple Looping Statements And Leader Conditions

              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by
              #13

              @Ketan__Patel__0011
              Additional to @Bonnie's latest.

              i generate this string using my encryption algorithm

              So should it not be a byte array/vector rather than a string?

              Ketan__Patel__0011K 1 Reply Last reply
              0
              • JonBJ JonB

                @Ketan__Patel__0011
                Additional to @Bonnie's latest.

                i generate this string using my encryption algorithm

                So should it not be a byte array/vector rather than a string?

                Ketan__Patel__0011K Offline
                Ketan__Patel__0011K Offline
                Ketan__Patel__0011
                wrote on last edited by
                #14

                @JonB

                Thanks For Reply

                ByteArray Or Vector Is good concept but it's is not good for sensitive data

                and even it is not good for any encrypted data or any sensitive data

                And Otherthing is am able to write this data in any text file

                but when i try to save this string in my MYSQL Database that time it is can't store
                with complete and proper data some characters are changes

                Please Help me to solve this problem

                This problem spoiled my whole day

                JonBJ B 2 Replies Last reply
                0
                • Ketan__Patel__0011K Ketan__Patel__0011

                  @JonB

                  Thanks For Reply

                  ByteArray Or Vector Is good concept but it's is not good for sensitive data

                  and even it is not good for any encrypted data or any sensitive data

                  And Otherthing is am able to write this data in any text file

                  but when i try to save this string in my MYSQL Database that time it is can't store
                  with complete and proper data some characters are changes

                  Please Help me to solve this problem

                  This problem spoiled my whole day

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #15

                  @Ketan__Patel__0011 said in std::string to QString can't convert properly:

                  ByteArray Or Vector Is good concept but it's is not good for sensitive data
                  and even it is not good for any encrypted data or any sensitive data

                  No idea what you are talking about here. I never said you should not encrypt. I asked whether the result of the encryption isn't a byte array rather than a string as you say it is. It looks like bytes and not characters to me. But if you say it's text that's up to you.

                  And Otherthing is am able to write this data in any text file

                  Regardless of encoding/codec?

                  but when i try to save this string in my MYSQL Database that time it is can't store
                  with complete and proper data some characters are changes

                  I wonder if that's because it's bytes and not text?

                  Ketan__Patel__0011K 1 Reply Last reply
                  1
                  • Ketan__Patel__0011K Ketan__Patel__0011

                    @JonB

                    Thanks For Reply

                    ByteArray Or Vector Is good concept but it's is not good for sensitive data

                    and even it is not good for any encrypted data or any sensitive data

                    And Otherthing is am able to write this data in any text file

                    but when i try to save this string in my MYSQL Database that time it is can't store
                    with complete and proper data some characters are changes

                    Please Help me to solve this problem

                    This problem spoiled my whole day

                    B Offline
                    B Offline
                    Bonnie
                    wrote on last edited by Bonnie
                    #16

                    @Ketan__Patel__0011 I don't think anyone can / want to help you if you don't listen to anyone.
                    Here I'll tell you what I usually do to store encrypted data to database.
                    Option 1: I use QByteArray to store the encrypted data, and then save it to database as BLOB.
                    Option 2: I convert it to hex / base64 string, and then save it to database as string.
                    That's over. I'll not reply this post anymore.

                    1 Reply Last reply
                    3
                    • JonBJ JonB

                      @Ketan__Patel__0011 said in std::string to QString can't convert properly:

                      ByteArray Or Vector Is good concept but it's is not good for sensitive data
                      and even it is not good for any encrypted data or any sensitive data

                      No idea what you are talking about here. I never said you should not encrypt. I asked whether the result of the encryption isn't a byte array rather than a string as you say it is. It looks like bytes and not characters to me. But if you say it's text that's up to you.

                      And Otherthing is am able to write this data in any text file

                      Regardless of encoding/codec?

                      but when i try to save this string in my MYSQL Database that time it is can't store
                      with complete and proper data some characters are changes

                      I wonder if that's because it's bytes and not text?

                      Ketan__Patel__0011K Offline
                      Ketan__Patel__0011K Offline
                      Ketan__Patel__0011
                      wrote on last edited by Ketan__Patel__0011
                      #17

                      @JonB

                      my Whole Process

                      1 -> define a normal string like:
                      std::string data="Welcome For Process";
                      2 -> Applying my encryption algorithm on this string
                      3 -> then store encrypted string into my file
                      4 -> Now for Backup i am try to save my encrypted string in MYSQL Database

                      But i can't store my encrypted string properly, some character are changed

                      otherthing is when open my encrypted string file in notepad
                      then it show it is ANSI encoding

                      Please help me to solve this problem

                      Again My Major problem is
                      i want to store my encrypted string in MYSQL Database

                      JonBJ mrjjM 2 Replies Last reply
                      0
                      • Ketan__Patel__0011K Ketan__Patel__0011

                        @JonB

                        my Whole Process

                        1 -> define a normal string like:
                        std::string data="Welcome For Process";
                        2 -> Applying my encryption algorithm on this string
                        3 -> then store encrypted string into my file
                        4 -> Now for Backup i am try to save my encrypted string in MYSQL Database

                        But i can't store my encrypted string properly, some character are changed

                        otherthing is when open my encrypted string file in notepad
                        then it show it is ANSI encoding

                        Please help me to solve this problem

                        Again My Major problem is
                        i want to store my encrypted string in MYSQL Database

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by
                        #18

                        @Ketan__Patel__0011 said in std::string to QString can't convert properly:

                        2 -> Applying my encryption algorithm on this string

                        And how does your encryption algorithm work? Is it really producing text characters from text characters, or is it actually manipulating and producing bytes?

                        otherthis is when open my encrypted string file in notepad
                        then it show it is ANSI encoding

                        Not sure that tells you anything from Notepad, but I'm not certain.

                        Please help me to solve this problem

                        So you keep saying.

                        i want to store my encrypted string in MYSQL Database

                        Yes, we understand this.

                        @Bonnie's two options are indeed the normal way to save any encrypted data to a database.

                        1 Reply Last reply
                        1
                        • Ketan__Patel__0011K Ketan__Patel__0011

                          @JonB

                          my Whole Process

                          1 -> define a normal string like:
                          std::string data="Welcome For Process";
                          2 -> Applying my encryption algorithm on this string
                          3 -> then store encrypted string into my file
                          4 -> Now for Backup i am try to save my encrypted string in MYSQL Database

                          But i can't store my encrypted string properly, some character are changed

                          otherthing is when open my encrypted string file in notepad
                          then it show it is ANSI encoding

                          Please help me to solve this problem

                          Again My Major problem is
                          i want to store my encrypted string in MYSQL Database

                          mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by mrjj
                          #19

                          @Ketan__Patel__0011
                          Hi
                          Since its not unicode or UTF8 or real text at all you cannot just store it in the DB as it expects it to be valid text
                          with valid encoding.

                          So do as @Bonnie says and store them in a blop via QByteArray.
                          Like this sample storing images.
                          https://wiki.qt.io/How_to_Store_and_Retrieve_Image_on_SQLite

                          Note, the type used for creating the table
                          query.exec( "CREATE TABLE IF NOT EXISTS imgTable ( filename TEXT, imagedata BLOB )" );

                          Then it won't alter your data and it should work.
                          Your output from the encryption is no longer valid text. Treat it as a binary thing and
                          use QByteArray in case it might add a zero in there. std::string and QString is not ok for this sort of data
                          in many cases.

                          1 Reply Last reply
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