Re: LRC calculation... What did I miss? - C# Discussion Boards

7-Nov-09 18:46

I'm sorry if anyone posted this question before, but i was wondering how can i remove and XML tag, and i mean just the tag not the entire element example:

 <font face="Arial">
  <font style="FONT-SIZE: 12pt">Un tehnician în munca lui se foloseşte de diverse scule. Aproape orice trusă de scule conţine una sau mai multe şurubelniţe drepte (vezi figura1 </font>
  <font size="3">si 7</font>
  <font size="3">).</font>
</font>

to become :

<font face="Arial">
      <font style="FONT-SIZE: 12pt">Un tehnician în munca lui se foloseşte de diverse scule. Aproape orice trusă de scule conţine una sau mai multe şurubelniţe drepte (vezi figura1 </font>si 7 ).
    </font>

ericwnws8-Nov-09 6:51

ericwnws

8-Nov-09 6:51

This is a tough question to answer without knowing the overall goal of the routine you are trying to write.

If you are just trying to eliminate unnecessary HTML, I recommend using a tool like HTML Tidy.

Writing your own solution to clean up HTML would require a great deal of effort.

If you simply want to remove all instances of and the corresponding surrounding text from your XML, there are a couple of options:
1 - Load XML into XmlDocument and use XSLT to transform output the way you like. You would have a XSLT template to match font[@size="3"] which would just output the inner content.
2 - Loop through the string, looking for instances of and build a new string by adding the text between the and the next tag, eliminating the tags.

My guess is that you are looking to cleanup unnecessary HTML, so I would go with a third party option for doing this.

toby318-Nov-09 9:54

8-Nov-09 9:54

Unfortunetly i never used XSLT and i don't really know how to used but that sounds like a good idea. I'll try to use it. And the sencond option doesn't really work for me because the input and output xml may vary very much.

Any help with XSLT world really be apreciated

ericwnws9-Nov-09 4:30

ericwnws

9-Nov-09 4:30

I've not actually tested the code samples below, but they should get you started.

Create a file called mytransform.xslt with the following content:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" ><br />
<br />
  <xsl:output method="xhtml" omit-xml-declaration="yes" indent="no" /><br />
<br />
  <xsl:template match="/"><br />
    <xsl:apply-templates select="font" /><br />
  </xsl:template><br />
<br />
  <xsl:template match="font[@size='3']"><br />
    <xsl:value-of select="." disable-output-escaping="yes" /><br />
  </xsl:template><br />
</xsl:stylesheet>

Use the following C# code in conjunction with the new XSLT to transform:

/* load content to be filtered into XmlDocument */<br />
string contentToTransform = "<font>my text <font size=\"3\">some text</font> more text <font size=\"3\">end text</font></font>"; <br />
XmlDocument docToTransform = new XmlDocument(); <br />
docToTransform.LoadXml(contentToTransform); <br />
<br />
/* create XslTransform object where mytransform.xslt is the XSLT to use for the transformation */<br />
XmlDocument xDoc = new XmlDocument();<br />
xDoc.Load(HttpContext.Current.Server.MapPath("/mytransform.xslt")); /* assumes in the root of your site, adjust appropriately */<br />
XslTransform xsl = new XslTransform(); <br />
xsl.Load(xDoc);<br />
<br />
/* transform the content */<br />
StringWriter sw = new StringWriter();<br />
HtmlTextWriter writer = new HtmlTextWriter(sw);<br />
xsl.Transform(docToTransform, null /* XsltArgumentList */, writer)<br />
<br />
/* sw.ToString() will return the transformed data, if you are doing this in an ASPX page, you can override the Render and use the HtmlTextWriter that is passed to that method to output the content to screen */

toby3110-Nov-09 8:02

LRC calculation... What did I miss? [modified] Solved

10-Nov-09 8:02

Thank you very much

Kiotaya7-Nov-09 18:39

7-Nov-09 18:39

I need to get the LRC (longitudinal redundancy check) value of a string. This data is being sent to a credit card processing network over SSL. After I get the LRC I am coverting it to string, then to a byte, and adding it to the end of a byte[] to send through SSL. When I send the transaction I am getting a NAK response to my LRC. What am I doing wrong?

I have tried this

RequestMessage contains Message+ETX only

public static char ReturnLRC(string RequestMessage)
{
    int lrcAnswer = 0;
    for (int i = 0; i < RequestMessage.Length; i++)
    {
     lrcAnswer = lrcAnswer ^ (Byte)(Encoding.UTF7.GetBytes(RequestMessage.Substring(i, 1))[0]);
    }
     return (Char)lrcAnswer;
}

char charLrc = ReturnLRC(Trans);
string lrcString = charLrc.ToString();
byte[] LRC = unicode.GetBytes(lrcString );
fullMessage[addLRCHere] = LRC[0];

I have also tried this seperatly.

RequestMessage contains Message+ETX only

public static char theReturnLRC(string RequestMessage)
{
     int lrcAnswer = 0;
     byte[] byArray = Encoding.UTF7.GetBytes(RequestMessage);

     foreach (byte curByte in byArray)
     {
                 lrcAnswer ^= curByte;
     }
             return (char)lrcAnswer;
}

char charLrc = ReturnLRC(Trans);
string lrcString = charLrc.ToString();
byte[] LRC = unicode.GetBytes(lrcString );
fullMessage[addLRCHere] = LRC[0];

Neither process works, are the methods incorrect or is my conversions afterwards messing everything up? Thanks in advance for any help or advice.

Removing all the conversion confusion I found that I was generating the correct LRC. Thanks Everyone!!!

Kiotaya

modified on Monday, November 16, 2009 10:57 AM

OriginalGriff7-Nov-09 21:53

OriginalGriff

7-Nov-09 21:53

I am amazed that a credit card company is using only LRC - I would have thought at least CRC-16.

However, assuming LRC is what they want, then I would be reasonably sure that it is the various conversions that are causing the problem. You are starting with a UTF16, convering it to a byte via UTF7, then back to a char (UTF16) and up to a string (still UTF16) and then back to a byte. I would start with a similar data set from them, and examine that. What do they send as the data, what do they send as the LRC? You should then be able to work it out from that.

No trees were harmed in the sending of this message; however, a significant number of electrons were slightly inconvenienced.

This message is made of fully recyclable Zeros and Ones

"Rumour has it that if you play Microsoft CDs backwards you will hear Satanic messages.Worse still, is that if you play them forwards they will install Windows"

Luc Pattyn8-Nov-09 1:17

8-Nov-09 1:17

Kiotaya wrote:
(Byte)(Encoding.UTF7.GetBytes(RequestMessage.Substring(i, 1))[0]

This does not seem right: you choose UTF7 encoding, however for each string character you only use the first byte GetBytes returns.

You should have two distinct steps:
- represent your string as a byte array in the encoding of your choice;
- calculate LRC on that byte array.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Kiotaya8-Nov-09 7:14

8-Nov-09 7:14

Thank you for your response Luc. However it looks like what you are telling me is what I did in the second example I show. Please correct me if I am wrong in this assumtion. Here is the second example.

RequestMessage contains Message+ETX only

public static char theReturnLRC(string RequestMessage)
{     
     int lrcAnswer = 0;     
     byte[] byArray = Encoding.UTF7.GetBytes(RequestMessage);
     
     foreach (byte curByte in byArray)     
     {                 
       lrcAnswer ^= curByte;     
     }             
       return (char)lrcAnswer;
}

char charLrc = ReturnLRC(Trans);
string lrcString = charLrc.ToString();
byte[] LRC = unicode.GetBytes(lrcString );
fullMessage[addLRCHere] = LRC[0];

Luc Pattyn8-Nov-09 7:39

8-Nov-09 7:39

OK, two comments:

1.

Kiotaya wrote:
string lrcString = charLrc.ToString();
byte[] LRC = unicode.GetBytes(lrcString );
fullMessage[addLRCHere] = LRC[0];

what is all this stuff? you perform calculations on bytes, turn the result in a char, then a string, then a byte array, and then take the first byte. Why can't theReturnLRC() just return the byte result for immediate use?

2.

Your LRC is starting from zero, and XORing the bytes. There are hundreds of "standard" checksums and the like (using XOR or ADD; using left shifts, with recycling some carry, etc). Are you sure this is the one you need? Can you confirm with a few simple examples that are known to be good?

This[^] says "...may be computed in software by the following algorithm...". While this[^] uses a different definition.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Luc Pattyn8-Nov-09 8:13

8-Nov-09 8:13

I forgot one remark:

if (I don't know, you haven't told us enough to be sure) your communication is basically binary possibly with an occasional letter or word embedded in it, then you should not be using any strings at all, instead you then should be using byte[] exclusively.

Do you have the full specification?

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Kiotaya9-Nov-09 5:44

9-Nov-09 5:44

I am going to be running some more tests today. I will give you more details this afternoon. Thank you very much for your help and time.

Kiotaya7-Jan-10 14:14

Re: LRC calculation...Solution pls...

7-Jan-10 14:14

Sorry I didn't reply to this much sooner but the help you game me help me clear up this problem.
Thanks Luc Pattyn and everyone else.

Member 77181421-Mar-11 21:24

Member 7718142

1-Mar-11 21:24

Hello would you be able to post the solution for this?
I have a scenario where its been mentioned that my message will be sent in the following format

STX Data ETX BCC

And that BCC = LRC - XOR over all characters excluding STX but including ETX.
I am kind of trying to figure out how this works?

Here is the LRCCalculation method I have implemented.

private char CalculateLongitudinalRedundancyCheck(string source)
        {
            int result = 0;
            for (int i = 0; i < source.Length; i++)
            {
                result = result ^ (Byte)(Encoding.ASCII.GetBytes(source.Substring(i, 1))[0]);
            }
            return (Char)result;
        }

I get the LRC from this and then what...!!
For ex: say my data is something like "345565645023495767714.12.1988021114:33 15.8001".

Re: LRC calculation...Solution pls...

Michael Sogos 202128-Jun-21 13:37

Michael Sogos 2021

28-Jun-21 13:37

I land to the same issue.
Guys how did you resolved it?

WIA and Windows 7

toby317-Nov-09 18:36

7-Nov-09 18:36

I've tried writing an application that is using WIA in Windows 7 and i get the classic
Exception from HRESULT: Ox80210015 which means that my cameras don't support WIA. But i've moved run the exe on my eeePC and it works. So my question is does anyone know if there are any problems with Windows 7 and WIA ?

Re: WIA and Windows 7

oeatek8-Dec-09 4:43

oeatek

8-Dec-09 4:43

I have the same problem. Works fine on XP SP3 but
no luck on Win 7!

Did you get anywhere with this?

Re: WIA and Windows 7

toby318-Dec-09 10:15

HOw to create MySql database backup programmatically in C#.net

8-Dec-09 10:15

Unfortunelty no, but i'm not quite sure that it's Windows 7, because i connected my Nokia Cell Phone via bluetooth by mistake and it worked as in i stop getting the error, beacause WIA reconised my phone cam. So it think that it might not be Windows 7 but the webcams that i was using (the funny this is that one of the is from Microsoft).

Maybe the drivers for the camera might be outdated.

But to be honest i not really sure what it the problem. If you find out anything please let me know

gopal_bnvs7-Nov-09 18:22

gopal_bnvs

7-Nov-09 18:22

Hi

I have the code to make the backup of the MySql database like this..

try
{
DateTime backupTime = DateTime.Now;
int year = backupTime.Year;
int month = backupTime.Month;
int day = backupTime.Day;
int hour = backupTime.Hour;
int minute = backupTime.Minute;
int second = backupTime.Second;
int ms = backupTime.Millisecond;

String tmestr = backupTime.ToString();
tmestr = "C:\\" + year + "-" + month + "-" + day + "-" + hour + "-" + minute + ".sql";
StreamWriter file = new StreamWriter(tmestr);
ProcessStartInfo proc = new ProcessStartInfo();
string cmd = string.Format(@"-u{0} -p{1} -h{2} {3} > {4};", "root", "password", "localhost", "dbfile", "backup.sql");
proc.FileName = "mysqldump";
proc.RedirectStandardInput = false;
proc.RedirectStandardOutput = true;
proc.Arguments = cmd;//"-u root -p smartdb > testdb.sql";
proc.UseShellExecute = false;
Process p = Process.Start(proc);
string res;
res = p.StandardOutput.ReadToEnd();
file.WriteLine(res);
p.WaitForExit();
file.Close();

}

catch (IOException ex)
{
MessageBox.Show("Disk full or other IO error , unable to backup!");
}
}

while executing the program it is showing an error as shown

"The system cannot find the file specified" with caption "Win32Exception was unhandled "...

can anyone help todo this.....

bump attempt

Luc Pattyn8-Nov-09 1:19