From: Robert Klemme <shortcutter@...>
Date: 2008-02-28T17:55:06+09:00
Subject: Re: extracting hex keys from file

2008/2/28, Ben Aroia <benaroia@gmail.com>:
> The java background is killing me here. ;) Thanks for pointing out the
>  IO#pos.

IMHO something else is killing you: you did give only fractions of
your problem description making it hard for people to come up with
suggestions.

Back to your problem: here's a more efficient solution than looping:

def read_hex_io(io, offset, count)
  io.seek offset, File::SEEK_SET
  bytes = io.read count
  bytes.unpack("H*").shift
end

def read_hex(file, offset, count)
  File.open(file, "rb") do |io|
    read_hex_io io, offset, count
  end
end

Note: use the block form of File.open to ensure timely and safe
closing of file descriptors.

Cheers

robert

-- 
use.inject do |as, often| as.you_can - without end