?
Solved

Bit mask error codes

Posted on 2009-05-15
10
Medium Priority
?
470 Views
Last Modified: 2013-11-07
Hi All

We have an application that returns error code data as bit mapped.

ie
1 - error 1
2 - error 2
4 - error 3
8 - error 4
16 error 5

etc

If the app returne either a 1,2,4,8... I kow the error, but more oft than not it is a combination of errors ie

9 - error 1 and error 4.

Does anyone have an algorithm to convert these decimals back ito the error codes. I have a list of codes.

Ideally I'd like to do this on SQL Server, but code behind would be ok.

Andy
0
Comment
Question by:Andy Green
  • 4
  • 3
  • 2
  • +1
10 Comments
 
LVL 16

Expert Comment

by:ToddBeaulieu
ID: 24396504
You need BITWISE operators
declare @ERROR_1 int
declare @ERROR_2 int
declare @ERROR_3 int
declare @ERROR_4 int
 
set @ERROR_1 = 1
set @ERROR_2 = 2
set @ERROR_3 = 4
set @ERROR_4 = 8
 
declare @err int
set @err = @ERROR_1 | @ERROR_3
print '@err = ' + convert(varchar, @err)
 
if (@err & @ERROR_1 = @ERROR_1)
  print 'ERROR 1'
if (@err & @ERROR_2= @ERROR_2)
  print 'ERROR 2'
if (@err & @ERROR_3 = @ERROR_3)
  print 'ERROR 3'
if (@err & @ERROR_4 = @ERROR_4)
  print 'ERROR 4'

Open in new window

0
 
LVL 75

Expert Comment

by:Aneesh Retnakaran
ID: 24396617
You need to use a logical AND operation

DECLARE @Error int
SELECT @Error = 9
SELECT CASE WHEN @Error&1 =0 THEN 'False' ELSE 'True' END as 'Error 1',
CASE WHEN @Error&2 =0 THEN 'False' ELSE 'True' END as 'Error 2',
CASE WHEN @Error&4 =0 THEN 'False' ELSE 'True' END as 'Error 3',
CASE WHEN @Error&8 =0 THEN 'False' ELSE 'True' END as 'Error 4'
0
 
LVL 3

Author Comment

by:Andy Green
ID: 24397769
Not sure I understand your solution, or maybe it's my descrition of the problem.
I get a decimal value from the external app, which when converted to binary, equates to an error code, where ever there ia a 1.
The posible values go up to 1024. ie
1,2,4,8,16,32,64,128,256,512,1024 11 possible errors.
I cant test for every posible combination, how do I take the decimal, convert to binary and map to the error codes.
Andy
0
Never miss a deadline with monday.com

The revolutionary project management tool is here!   Plan visually with a single glance and make sure your projects get done.

 
LVL 16

Expert Comment

by:ToddBeaulieu
ID: 24397816
Why wouldn't you test for every condition? You have to, in order to map to the error codes, right?
You do a bit-wise AND against a test code and if the result = the test code, then that error code is contained in the map.
0
 
LVL 3

Author Comment

by:Andy Green
ID: 24397894
I see what you are saying, yes I agree I have to test aginst each of the 11, but I dont see how I get from the decimal to the actual bits, that represent the errors.
I'll take a look over the weekend. Friday at 5 club now  (well I'm late) and that means beer.
Andy
0
 
LVL 16

Accepted Solution

by:
ToddBeaulieu earned 1500 total points
ID: 24411161
If you take a number, AND it with another number, it returns a result comprised of every BIT that was 1 in both numbers. Since you want to test for individual errors, you don't care what the "BITS" are. You simply need to see if the error code ANDed with a test error code is exactly equal to the test error code.
0
 
LVL 3

Author Closing Comment

by:Andy Green
ID: 31581950
Thanks - got it now. It was the conversion into binary that stumped me and it does it for you implicitly.

Andy
0
 
LVL 75

Expert Comment

by:Anthony Perkins
ID: 24414298
>>I dont see how I get from the decimal to the actual bits<<
You may not have any control over this, but there is no need to use decimals for this, an integer will suffice.  In fact if all you have are 11 variations then a smallint will do.
0
 
LVL 16

Expert Comment

by:ToddBeaulieu
ID: 24414344
"decimal" did not refer to a data type, but rather to "base 10".
0
 
LVL 75

Expert Comment

by:Anthony Perkins
ID: 24414545
Ah, good point.  I should read more carefully.
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

An alternative to the "For XML" way of pivoting and concatenating result sets into strings, and an easy introduction to "common table expressions" (CTEs). Being someone who is always looking for alternatives to "work your data", I came across this …
The PowerShell Core 6.0 of .NET release is just the beginning. The upcoming PowerShell Core 6.1 would have artificial intelligence and internet of things capabilities. So many things to look forward to in the upcoming release.
This video shows, step by step, how to configure Oracle Heterogeneous Services via the Generic Gateway Agent in order to make a connection from an Oracle session and access a remote SQL Server database table.
Using examples as well as descriptions, and references to Books Online, show the documentation available for date manipulation functions and by using a select few of these functions, show how date based data can be manipulated with these functions.

588 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question