urgent: vb6 code to calculate 16 bit CRC-CCITT - Visual Basic Discussion Boards

Henry Minute7-Apr-09 0:56

7-Apr-09 0:56

But you did ask. You asked every CP member.

If you had said that you had googled and found nothing, that would be a different story, but as others have pointed out there are loads of suitable answers on the web.

If you had tried to use one of those solutions and got stuck whilst doing so, you would have almost certainly got lots of help.

On the other hand, if it appears that someone is not capable of doing basic research first, they should not expect help.

I really do hope that you find one of the links suggested by others useful, and solve your problem.

But google is your best friend in situations like this.

Good luck! Smile | :)

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Re: Paging in Datagrids

parkash_C7-Apr-09 1:40

parkash_C

7-Apr-09 1:40

i am a starter dear ,it takes me time to understand
i never search code, i look for proper function
they enhance your logic
i was looking for a datagrid property or function,like in web forms
which i dont thing exist, if there is do tell me Wink | ;)

Re: Paging in Datagrids

Henry Minute7-Apr-09 1:48

Henry Minute

7-Apr-09 1:48

AFAIK there is no property or function in the datagrid control to allow paging (by the way is it a DataGrid or a DataGridView? It makes no difference in this case, but it probably will if you have othter problems).

There are lots of different ways to do it, so have a look at the links given by others to see if there is something that can help you, or at least give you some ideas to implement your own solution.

vb and flash

ahlamissa6-Apr-09 2:38

ahlamissa

6-Apr-09 2:38

when press button in flash talk to vb to show certain form

Re: vb and flash

Dave Kreskowiak6-Apr-09 10:45

Dave Kreskowiak

6-Apr-09 10:45

AFAIK, Flash has no methods of communication to notify its host of anything happening.

In other words, there's no way for your code to know a button has been clicked in a Flash window.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: vb and flash

Christian Graus6-Apr-09 16:58

Christian Graus

6-Apr-09 16:58

This is not a question. Try posting something that is, and that includes what you did to try to solve your issue.

Christian Graus

Driven to the arms of OSX by Vista.

"I am new to programming world. I have been learning c# for about past four weeks. I am quite acquainted with the fundamentals of c#. Now I have to work on a project which converts given flat files to XML using the XML serialization method" - SK64 ( but the forums have stuff like this posted every day )

Re: vb and flash

Anubhava Dimri6-Apr-09 21:50

Anubhava Dimri

6-Apr-09 21:50

Flash has support programming.so You Can use Script on Flash for Running Application.

Best Regard
Anubhava Dimri

mailto: anubhava.prodata@gmail.com

urgent: vb6 code to calculate 16 bit CRC-CCITT

singende6-Apr-09 2:15

singende

6-Apr-09 2:15

please help i need a visual basic 6 conversion or equivalence of the below code
i tried several codes but i am getting different results

urgently in need of help

/*************************************************************************
Function: 16 bit CRC-CCITT calculation
--------------------------------------------------------------------------
Call: calc_crc(unsigned short crc_buff, unsigned char input)
--------------------------------------------------------------------------
Response: Newly calculated 16 bit CRC checksum
--------------------------------------------------------------------------
Description: Calculates the checksum for 'input' in accordance with the CRC polynomial x^16 + x^12 + x^5 + 1. 'crc_buff' is the previously calculated checksum. This must be set to 0xFFFF at the beginning of a test sequence.
*************************************************************************/
unsigned short calc_crc(unsigned short crc_buff, unsigned char input)
{
unsigned char i;
unsigned short x16; // we’ll use this to hold the XOR mask
for (i=0; i<8; i++)
{
// XOR current D0 and next input bit to determine x16 value
if( (crc_buff & 0x0001) ^ (input & 0x01) )
x16 = 0x8408;
else
x16 = 0x0000;
// shift crc buffer
crc_buff = crc_buff >> 1;
// XOR in the x16 value
crc_buff ^= x16;
// shift input for next iteration
input = input >> 1;
}
return(crc_buff);
}
File: UMB-Protokoll 1_0 Version 1_5_e.doc,
Version 1.5,
Status 14.12.2007
37
// ******************* MAIN ************************************
void main(void)
{
// example: CRC for 8 Bytes
unsigned char values[8] =
{0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37};
// initialise startvalue FFFFh
unsigned short crc = 0xFFFF;
// calculation
for(int n = 0; n < 8; n++)
{
crc = calc_crc(crc, values[n]);
}
// output
printf("\ndata: 30h, 31h, 32h, 33h, 34h, 35h, 36h, 37h");
printf("\nCRC: %04Xh\n", crc);
}

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

Jay Royall6-Apr-09 2:24

Jay Royall

6-Apr-09 2:24

Can you post your attempts at converting this and explain what is going wrong? It is unlikely that someone will just do it for you, unless you pay them of course!

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini6-Apr-09 3:32

CPallini

6-Apr-09 3:32

the following is VBA (VB6 is dead on my system)

Private Sub CommandButton1_Click()
    Dim crc As Long
    Dim n As Integer
    Dim values(8) As Byte
    crc = &HFFFF&
    
    For n = 0 To 7
        values(n) = &H30 + n
    Next n
    For n = 0 To 7
        crc = calc_crc(crc, values(n))
    Next n
    MsgBox ("Crc " & crc)
   
End Sub

Private Function calc_crc(ByVal crc_buff As Long, ByVal inp As Byte) As Long
    Dim i As Byte
    Dim x16 As Long
    For i = 0 To 7
    
        If ((crc_buff And 1) Xor (inp And 1)) = 1 Then
            x16 = &H8408&
        Else
            x16 = 0
        End If
        crc_buff = crc_buff \ 2
        crc_buff = crc_buff Xor x16
        inp = inp \ 2
    Next i
    calc_crc = crc_buff
End Function

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

singende6-Apr-09 4:08

singende

6-Apr-09 4:08

please be blessed i have seen some light with your code. i will come back to you in due course let me try to implement it it looks it will do the magic

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

0x3c06-Apr-09 4:11

0x3c0

6-Apr-09 4:11

That code might not work correctly. Doesn't VB6 implicitly pass all parameters by reference?

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini6-Apr-09 5:01

CPallini

6-Apr-09 5:01

Computafreak wrote:
Doesn't VB6 implicitly pass all parameters by reference?

Unless you specify, as I did, ByVal.
Smile | :)

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

0x3c06-Apr-09 5:53

0x3c0

6-Apr-09 5:53

Doesn't the calc_crc method try to alter the parameters in the for-loop?

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini6-Apr-09 10:44

CPallini

6-Apr-09 10:44

Nope, none of the two versions, of course.
Smile | :)

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

0x3c06-Apr-09 23:24

0x3c0

6-Apr-09 23:24

CPallini wrote:

Private Function calc_crc(ByVal crc_buff As Long, ByVal inp As Byte) As Long
    Dim i As Byte
    Dim x16 As Long
    For i = 0 To 7
    
        If ((crc_buff And 1) Xor (inp And 1)) = 1 Then
            x16 = &H8408&
        Else
            x16 = 0
        End If
        <big>crc_buff = crc_buff \ 2</big>
        <big>crc_buff = crc_buff Xor x16</big>
        <big>inp = inp \ 2</big>
    Next i
    calc_crc = crc_buff
End Function

Either way, my VB6 is rather rusty. I've not used it for years, so I could be wrong

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini6-Apr-09 23:31

CPallini

6-Apr-09 23:31

Both crc_buff and inp are passed by value (ByVal), i.e. the called function (calc_crc) receives a copy of each passed parameter and cannot change the original ones.
Smile | :)

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

0x3c07-Apr-09 1:36

0x3c0

7-Apr-09 1:36

Ugh. Stupid mistake. Sorry about that

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini7-Apr-09 1:48

CPallini

7-Apr-09 1:48

Don't worry, my VB6 is rusty too (actually VB6 by itself is quite rusty... Roll eyes | :rolleyes:

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

singende6-Apr-09 5:11

singende

6-Apr-09 5:11

i am newbie into this vb6.
Tell me how best i can implement this, What i really want is to get two check sum bytes for my stream of data i am sending via a MScomms and use it again to cross check the check sum of the incoming data packet and so the validity of the incoming packet

the frame i am sending is like this
0x01 0x10 0x01 0xF0 0x0A 0x02 0x23 0x10 0x10 0x00 0x59 0x16 0x1F ...22bytes with 2 bytes for check sum

And i am receiving a request of length 16bytes so i want to verify the request then send a reply as required by the protocol

will be very thankful for help

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

Vimalsoft(Pty) Ltd6-Apr-09 21:05

Vimalsoft(Pty) Ltd

6-Apr-09 21:05

VB6

I'd better be a newbie in (Hair Styling) than be a newbie in VB6.

Do you know what year is it ? They have invented a First Flying car read here http://dsc.discovery.com/news/2009/01/22/flying-car.html[^]

When VB6 was used we were using Camels and Horses to work Smile | :)

Vuyiswa Maseko,

Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."

C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
www.ITS.co.za

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

Dave Kreskowiak6-Apr-09 10:43

Dave Kreskowiak

6-Apr-09 10:43

Schmuck! Now you're stuck supporting the code you posted! Laugh | :laugh:

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

CPallini6-Apr-09 10:46

CPallini

6-Apr-09 10:46

My code is unsopported by definition: I'm a Klingon programmer [^].
Laugh | :laugh:

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

Christian Graus6-Apr-09 16:59

Christian Graus

6-Apr-09 16:59

Why are you using VB6 ? Do you hate yourself ?

Re: urgent: vb6 code to calculate 16 bit CRC-CCITT

DaveyM697-Apr-09 0:37

DaveyM69

7-Apr-09 0:37

Christian Graus wrote:
Why are you using VB6 ? Do you hate yourself ?

Classic! Made my day Laugh | :laugh:

- added to my signature Big Grin | :-D

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)
Why are you using VB6 ? Do you hate yourself ? (Christian Graus)

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