From: anansi <kazaam@...>
Date: 2007-06-07T03:00:11+09:00
Subject: best DRY solution for this task

Hi,
I have a certain problem here and can't find a proper DRY solution for 
this so I wondered if someone here has an idea and could help me.

I'm reading a file byte for byte. This file is structured and I try to 
give out each structures element and the meaning of it. So let's pretend
the file content would be this in bytes (you get it e.g. with 
file.read(7)): 1 3d 0 233 0 1 2f


now I wanna read the file byte for byte and output if the first 3 bytes 
are equal 1 3d 0:
     startflag : good (1 3d 0)
or if the check fails
     startflag : bad (2 3d 0)
now the fourth byte is read and if it is 1
     debg_mode : on
if it is 0 : out and if it is 233 : don't know  ...


My problem with a DRY solution is that some bytes in this file are 
grouped together and have just together a meaning as the first three 
starting bytes: 1 3d 0 at the beginning and some bytes have alone a 
meaning as the fourth byte 233 in the example.
And that everything has another ouput. So the first three bytes meaning 
is another than the one of the fourt or the fifth byte.

My solution until now:


target = open('testfile.txt','r')

startflag = target.read(3)
     print("startflag: ")
     if startflag == $startflag # here I took a global var because 
"\x13d0" didn't work
      print(" good")
     else
      print(" bad")
     end
     startflag.each_byte  do |x|
     printf("%x ",x)
                          end
puts ""


dbg_mode = target.read(1)
printf("dbg_mode: ")
    if dbg_mode == "\x1"
      print(" on")
    elseif dbg_mode == "\x255"
      print("don't know")
    else
      print(" bad")
    end
dbg_mode.each_byte  {|x| printf("%x ",x) }
puts ""

and so on and on and on...

so how can I do this check and outputting better? Because there are many 
bytes with many different meanings and as said sometimes I need to read 
in 4 bytes then just one then again 2 bytes... is this at all possible 
to do dry-like?

thanks



-- 
greets

                     one must still have chaos in oneself to be able to 
give birth to a dancing star