From: Joel VanderWerf <vjoel@...>
Date: 2006-10-19T11:54:08+09:00
Subject: Re: Bitwise operations

Rob Lee wrote:
> Hi,
> 
> I have a binary packet stored in a string.  I also have a packet 
> specification and I'd like to print the first byte as a hex value to 
> check it corresponds to the expected value from the specification 
> ('7F').  I can't understand how to access the first byte from a string 
> (a series of 8 bit bytes I believe).  There don't seem to be any 
> bit-shift operators in Ruby for a string - could anybody advise how I go 
> about this ?

It would be overkill for just getting the first byte, but you may find 
bit-struct helpful in defining and parsing binary strings.

http://raa.ruby-lang.org/project/bit-struct/

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407