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Structures in VC

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  • L Offline
    L Offline
    Lost User
    wrote on last edited by
    #1

    how do we copy data from a buffer to a structure

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    • L Lost User

      how do we copy data from a buffer to a structure

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      A Offline
      Abebe
      wrote on last edited by
      #2

      you can use bitwise operators (>>, &, |, <<) to copy certain bytes from a buffer to the corresponding field in the structure. Er zit een korstje op mijn aars.

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      • A Abebe

        you can use bitwise operators (>>, &, |, <<) to copy certain bytes from a buffer to the corresponding field in the structure. Er zit een korstje op mijn aars.

        K Offline
        K Offline
        kakan
        wrote on last edited by
        #3

        Or memcpy(&struct, buffer, sizeof(struct));

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        • L Lost User

          how do we copy data from a buffer to a structure

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          toxcct
          wrote on last edited by
          #4

          you cannot copy a whole group of varialbes into a structure, except at its initialization. the rest of the time, you'll have to point each member of the structure to affect it... this is because generally, the members of a structure may be by side, but not necessarily...


          TOXCCT >>> GEII power
          [toxcct][VisualCalc]

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          • L Lost User

            how do we copy data from a buffer to a structure

            J Offline
            J Offline
            Jose Lamas Rios
            wrote on last edited by
            #5

            Try being more specific. How is the buffer declared? What's its content? In what format? How is the structure declared? Withouth such details, the answer can only be as vague as your question: Q: how do we copy data from a buffer to a structure? A: you extract pieces of data from the buffer and put them into the appropriate fields of the structure. :) -- jlr http://jlamas.blogspot.com/[^]

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            • A Abebe

              you can use bitwise operators (>>, &, |, <<) to copy certain bytes from a buffer to the corresponding field in the structure. Er zit een korstje op mijn aars.

              L Offline
              L Offline
              Lost User
              wrote on last edited by
              #6

              actually the thing isthat we have stored data in a buffer.....now we declared an aaray of a structure to copy that data.abb i dont know that how do we specify no of bytes using bitwize operator.

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              • J Jose Lamas Rios

                Try being more specific. How is the buffer declared? What's its content? In what format? How is the structure declared? Withouth such details, the answer can only be as vague as your question: Q: how do we copy data from a buffer to a structure? A: you extract pieces of data from the buffer and put them into the appropriate fields of the structure. :) -- jlr http://jlamas.blogspot.com/[^]

                L Offline
                L Offline
                Lost User
                wrote on last edited by
                #7

                i have read a log file through buffer.it tells us that how many calls are in the log file!now wat i have to do is that i have to copy the certain bytes of each call in a structure. lets suppose 364 bytes i have to copy of each call!

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                • K kakan

                  Or memcpy(&struct, buffer, sizeof(struct));

                  C Offline
                  C Offline
                  Cedric Moonen
                  wrote on last edited by
                  #8

                  That's a solution but you'll need to be sure that the data in the buffer has the same format as your structure. What I mean is that in your structure, the members will be aligned on a 8 bytes boundary (but you can change that). So, if it is not the case in your buffer, you will have some problems.

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                  • J Jose Lamas Rios

                    Try being more specific. How is the buffer declared? What's its content? In what format? How is the structure declared? Withouth such details, the answer can only be as vague as your question: Q: how do we copy data from a buffer to a structure? A: you extract pieces of data from the buffer and put them into the appropriate fields of the structure. :) -- jlr http://jlamas.blogspot.com/[^]

                    L Offline
                    L Offline
                    Lost User
                    wrote on last edited by
                    #9

                    now tell me how do we extract peices of data from buffer?

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                    • L Lost User

                      now tell me how do we extract peices of data from buffer?

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                      toxcct
                      wrote on last edited by
                      #10

                      see this[^] posted on the forum yesterday... it's quite similar as you extract datas from a buffer...


                      TOXCCT >>> GEII power
                      [toxcct][VisualCalc]

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                      • L Lost User

                        how do we copy data from a buffer to a structure

                        L Offline
                        L Offline
                        Lost User
                        wrote on last edited by
                        #11

                        we have character data in our main buffer and also we need to pack two bytes of data from our main buffer into 1 byte of data in our small buffer.how we'll do this:mad:

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                        • L Lost User

                          we have character data in our main buffer and also we need to pack two bytes of data from our main buffer into 1 byte of data in our small buffer.how we'll do this:mad:

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                          toxcct
                          wrote on last edited by
                          #12

                          hey hey hey, please calm down, otherwise, noboody will help you... moreover, you question is far from being clean... what are those buffers ? i've understood you had only one, and now, you talk of two buffers ! :omg: i think the best way to make us understand is to provide so little schemas (into <pre></pre> tags) and some code... explicit also you question clearly, with what you have, what you want, what don't work and what error messages are sent.


                          TOXCCT >>> GEII power
                          [toxcct][VisualCalc]

                          L 1 Reply Last reply
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                          • T toxcct

                            hey hey hey, please calm down, otherwise, noboody will help you... moreover, you question is far from being clean... what are those buffers ? i've understood you had only one, and now, you talk of two buffers ! :omg: i think the best way to make us understand is to provide so little schemas (into <pre></pre> tags) and some code... explicit also you question clearly, with what you have, what you want, what don't work and what error messages are sent.


                            TOXCCT >>> GEII power
                            [toxcct][VisualCalc]

                            L Offline
                            L Offline
                            Lost User
                            wrote on last edited by
                            #13

                            :(( actually i'm in office.....n m tensed as well...oki let me explain again that i've read a file and stored its data in buffer righttt! now i have to copy some specific bytes from that buffer to a structure.the thing is that the data in my file is stored in characters.means there is one character at each index.and i have to pick two characters at a time and store it in a structure....right now plzz tell me how we'l do this.......

                            C M 2 Replies Last reply
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                            • L Lost User

                              :(( actually i'm in office.....n m tensed as well...oki let me explain again that i've read a file and stored its data in buffer righttt! now i have to copy some specific bytes from that buffer to a structure.the thing is that the data in my file is stored in characters.means there is one character at each index.and i have to pick two characters at a time and store it in a structure....right now plzz tell me how we'l do this.......

                              C Offline
                              C Offline
                              Cedric Moonen
                              wrote on last edited by
                              #14

                              If you could post your structure, this would help a little bit more. You have to understand that we cannot see what's on your screen so we have to guess what you want to do with the little clues you gave us. Ok, in which 'format' you want to store this two characters ? Is it an integer or a string ? If it is a string, you can simply do that: struct.MyString[0] = Buffer[Index]; struct.MyString[1] = Buffer[Index+1]; If it is an integer, you could do that: char Temp[3]; Temp[0] = Buffer[Index]; Temp[1] = Buffer[Index+1]; Temp[2] = '\0'; struct.MyInt = atoi(Temp); If it doesn't help, try to be more specific and POST CODE !!

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                              • L Lost User

                                :(( actually i'm in office.....n m tensed as well...oki let me explain again that i've read a file and stored its data in buffer righttt! now i have to copy some specific bytes from that buffer to a structure.the thing is that the data in my file is stored in characters.means there is one character at each index.and i have to pick two characters at a time and store it in a structure....right now plzz tell me how we'l do this.......

                                M Offline
                                M Offline
                                MailtoGops
                                wrote on last edited by
                                #15

                                Nadia, Could you please provide us your structure prototype?. And I also intersteded in your buffer data?. How they are categorised/delimited from each item? What do you mean by big buffer and small buffer :)? " Action without vision is only passing time, Vision without action is merely day dreaming, But vision with action can change the world " - Words from Nelson Mandela Thanks & Regards, Gopalakrishnan

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                                • M MailtoGops

                                  Nadia, Could you please provide us your structure prototype?. And I also intersteded in your buffer data?. How they are categorised/delimited from each item? What do you mean by big buffer and small buffer :)? " Action without vision is only passing time, Vision without action is merely day dreaming, But vision with action can change the world " - Words from Nelson Mandela Thanks & Regards, Gopalakrishnan

                                  T Offline
                                  T Offline
                                  toxcct
                                  wrote on last edited by
                                  #16

                                  enough !!! :mad: there are too many posts on CP Forums that are just reposts of what's just been said right before... Cedric and I already asked what you just posted there. did you bother read the answers before making yours ?


                                  TOXCCT >>> GEII power
                                  [toxcct][VisualCalc]

                                  M 1 Reply Last reply
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                                  • T toxcct

                                    enough !!! :mad: there are too many posts on CP Forums that are just reposts of what's just been said right before... Cedric and I already asked what you just posted there. did you bother read the answers before making yours ?


                                    TOXCCT >>> GEII power
                                    [toxcct][VisualCalc]

                                    M Offline
                                    M Offline
                                    MailtoGops
                                    wrote on last edited by
                                    #17

                                    :) What you understood by all your post...:laugh: " Action without vision is only passing time, Vision without action is merely day dreaming, But vision with action can change the world " - Words from Nelson Mandela Thanks & Regards, Gopalakrishnan

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                                    • C Cedric Moonen

                                      That's a solution but you'll need to be sure that the data in the buffer has the same format as your structure. What I mean is that in your structure, the members will be aligned on a 8 bytes boundary (but you can change that). So, if it is not the case in your buffer, you will have some problems.

                                      T Offline
                                      T Offline
                                      Tim Smith
                                      wrote on last edited by
                                      #18

                                      Alignment can be adjusted and by default uses natual alignment up to 8 byte PODs. VC doesn't use 8 byte alignment. Tim Smith I'm going to patent thought. I have yet to see any prior art.

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                                      • T Tim Smith

                                        Alignment can be adjusted and by default uses natual alignment up to 8 byte PODs. VC doesn't use 8 byte alignment. Tim Smith I'm going to patent thought. I have yet to see any prior art.

                                        C Offline
                                        C Offline
                                        Cedric Moonen
                                        wrote on last edited by
                                        #19

                                        Tim Smith wrote: Alignment can be adjusted and by default uses natual alignment up to 8 byte PODs Yes, that's what I said :). Tim Smith wrote: VC doesn't use 8 byte alignment :doh: Err, pretty sure that it does. I had a bug two years ago because of that (loading data from a file and memcpy it to a struct) and I spent a lot of time to solve it. And it was because of the member struct alignement that was to 8 by default.

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