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Message
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| Vitor |
 Posted: Fri Oct 28, 2011 8:56 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| mattfarney wrote: |
| I had to add a structure like this to get the conversion to work. Some of the bytes converted to FFFFFF52 instead of 52. |
Now why do you think that would be?
I can just about see that you could use this for logging, though IMHO something a bit more business-related would have more value. It's all very well logging the message id, but when some user claims that transaction on customer x didn't make it through the infrastructure how are you going to trace that?
The OP is trying to invent his own assured delivery mechanism based on these ids. It's not impossible, in the same way my brother in law can get a supercharged V8 into his otherwise unmodified & somewhat rusty 2005 Blazer. It doesn't make it a good idea (though if he manages to avoid killing anyone else or hitting anything with value the downsides will be limited)
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| bruce2359 |
| Posted: Fri Oct 28, 2011 9:03 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9475
Location: US: west coast, almost. Otherwise, enroute.
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Units of work can't span multiple qmgrs. I've chatted with a few sysadmin/developer types that thought: "Hey, I can write an app that MQCONNects to two different qmgrs concurrently, then MQPUT/MQGET to queues one and/or the other, then MQCMIT/MQBACK both!'
Yes, but what if the first qmgr you MQCMIT works OK; but the 2nd fails? How do you backout what you've already committed? "That's easy," he said; "I'll just write the things I've committed to a file, and replay the file." Sound familiar?
Not so easy, he discovered.
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Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| mattfarney |
| Posted: Fri Oct 28, 2011 10:35 am Post subject: |
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Disciple
Joined: 17 Jan 2006
Posts: 167
Location: Ohio
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This statement is not 100% true.
| Quote: |
| Not all BYTE (hex) characters are printable. |
There are ways to encode binary values and have the result be printable (re: Base 64).
Assume I have a byte string of AMQ followed by \01, \04, and \13.
One printable encoding of that byte string is: 414D52010413
-mf |
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| fjb_saper |
| Posted: Fri Oct 28, 2011 10:51 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20763
Location: LI,NY
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| mattfarney wrote: |
This statement is not 100% true.
| Quote: |
| Not all BYTE (hex) characters are printable. |
There are ways to encode binary values and have the result be printable (re: Base 64).
Assume I have a byte string of AMQ followed by \01, \04, and \13.
One printable encoding of that byte string is: 414D52010413
-mf |
Even easier than base64 encoding: a hex representation of the byte array... 
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MQ & Broker admin |
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| bruce2359 |
| Posted: Fri Oct 28, 2011 11:03 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9475
Location: US: west coast, almost. Otherwise, enroute.
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We're talking about digital data. Why does it need to be printed anyway?
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I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| Vitor |
| Posted: Fri Oct 28, 2011 11:08 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| bruce2359 wrote: |
| We're talking about digital data. Why does it need to be printed anyway? |
Not printed but printable - the OP's trying to use it as a file name in his home spun assured delivery system.
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| bruce2359 |
| Posted: Fri Oct 28, 2011 11:14 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9475
Location: US: west coast, almost. Otherwise, enroute.
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How about this: His app could create a table of MsgIds and program-generated filenames - like MSG00001, MSG00002, and so on. No need to fiddle with the MsgId.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| Vitor |
| Posted: Fri Oct 28, 2011 11:16 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| bruce2359 wrote: |
| How about this: His app could create a table of MsgIds and program-generated filenames - like MSG00001, MSG00002, and so on. No need to fiddle with the MsgId. |
How about this: he uses the inbuilt assured delivery?
I wouldn't do it with files either.
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| bruce2359 |
| Posted: Fri Oct 28, 2011 12:39 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9475
Location: US: west coast, almost. Otherwise, enroute.
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| Vitor wrote: |
How about this: he uses the inbuilt assured delivery? |
What's fun about that? And it would be too easy.
Much better to write a needlessly and overly-complicated, and fraught-with-problems application program.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| gbaddeley |
| Posted: Sun Oct 30, 2011 2:21 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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| lyntongrice wrote: |
Below is a small sample program that produces the "wrong result".....i assune i must use a byte array instead of char?
The output for the following is:
Result: 414D5120514D30312020202020202020FFFFFF4EFFFF6
| Code: |
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(){
char name[41]="AMQ QM01 \275\364\250N\242\243\006";
char buffer[82]="";
char *pbuffer = buffer;
int rc = convertStrToHex(buffer, name);
printf( "Result: %s\n", pbuffer );
}
return 0;
}
int convertStrToHex(char *buffer, char str[10]){
int len = strlen(str);
int i;
for( i = 0; i < len ;i++ ){
sprintf(buffer, "%X", str[i]);
buffer +=2;
};
} |
Thanks for the help 
Lynton |
The sprintf needs format specification "%02X" to print 2 hex bytes per array entry.
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| mvic |
| Posted: Tue Nov 01, 2011 5:53 pm Post subject: |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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A few questions:
- Why char str[10] in the parameter list of convertStrToHex()? The code appears to be passing many more bytes than that.
- Why is the code using null-terminated strings? It appears to be intended to deal with non-terminated data that can have nulls in the middle of the data. If I am right about that, you would need to avoid strlen().
- unsigned char is probably needed, in order to make the %02X work the way it seems intended to work. gbaddeley is right to say %02X is needed rather than %X. But if you test it and find that that is not enough, unsigned char might be worth a try. |
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| mvic |
| Posted: Tue Nov 01, 2011 5:59 pm Post subject: |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| mattfarney wrote: |
I have a logging program that turns the msgId and corId into printable text.
I had to add a structure like this to get the conversion to work. Some of the bytes converted to FFFFFF52 instead of 52.
| Code: |
char hexValueHold[8];
string msgIdAsHex;
string bufferFix;
memcpy(hexValueHold," ",8);
sprintf(hexValueHold,"%02X",hold[i]);
bufferFix = hexValueHold;
if (bufferFix.substr(0,6) == "FFFFFF")
bufferFix = bufferFix.substr(6,2);
msgIdAsHex.append(bufferFix);
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-mf |
Like lyntongrice I suggest you experiment with using the "unsigned char" type. What type is the variable "hold", by the way? Even if the code you've written works (I cannot be sure it does), I still think it should be unnecessary to write that "if" test. |
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| mattfarney |
| Posted: Thu Nov 03, 2011 1:31 pm Post subject: |
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Disciple
Joined: 17 Jan 2006
Posts: 167
Location: Ohio
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I think you are correct.
| Quote: |
| unsigned char hold[24]; |
would probably remove the need for the manual removal of what looks a negative value to me (FFFFFFXX).
-mf |
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| gbaddeley |
| Posted: Thu Nov 03, 2011 2:41 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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Its Friday here, I'm feeling generous:
| Code: |
/* -------------------------------------------------------------
* Format a fixed length byte array into a null terminated
* string buffer as hexadecimal representations of the bytes.
* The size of WorkBuffer needs to be at least DataLen * 2 + 1.
* Returns pointer to hex characters.
*/
char *FormatHex( void *pData, int DataLen, char *pWorkBuffer )
{
int i;
unsigned char *pUData;
char *pBuffOut;
static char HexDigits[16] = "0123456789ABCDEF";
pUData = (unsigned char *)pData;
pBuffOut = pWorkBuffer;
for( i = 0 ; i < DataLen ; i++ )
{
*pBuffOut++ = HexDigits[ *pUData / 16 ];
*pBuffOut++ = HexDigits[ *pUData++ % 16 ];
}
*pBuffOut = '\0'; /* Null terminate */
return pWorkBuffer;
}
Usage:
char Work[50];
sprintf( "MsgIdHex=%s\n", FormatHex( Mqmd.MsgId, MQ_MSG_ID_LENGTH, Work ) ); |
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Glenn |
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| rekarm01 |
| Posted: Fri Nov 04, 2011 4:10 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 1415
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| gbaddeley wrote: |
| The sprintf needs format specification "%02X" to print 2 hex bytes per array entry. |
"%.2X" will probably work better. |
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