From: Joel VanderWerf <vjoel@...>
Date: 2006-11-21T08:11:40+09:00
Subject: Re: Fast 32 bit ints in ruby ?

devesh wrote:
> Hi Folks,
> 
> I want an efficient implementation of an Ipaddress class. The ones I
> have seen (for eg: lib/ipaddr.rb) all represent things internally in
> the form of a Bignum. And that is turning out to be a bottleneck for
> me. Ideally I would want to create some kind of a class, in which I can
> wrap in a normal C int and then operate with it directly. Does anyone
> know of how to do this ?. Another way would be to create a struct
> wrapping this int and then access that from my C extension (Like it is
> done with the Jukebox example in the Pickaxe book). I am new to ruby
> and to mixing C and ruby. What would be a good way to achieve the
> following interface:

What about packing the 4 bytes in a string:

p "192.168.1.2".split(".").map{|d|Integer(d)}.pack("C*")
# ==> "\300\250\001\002"

Unfortunately, there's no fast way to do & on strings of bits in pure 
ruby, AFAIK. Now, that might be a nice extension: bit operations on 
strings, including reading and writing bits n1 through n2 as a substring 
of bits, & ^ | on substrings of bits, etc.

Actually, maybe this will help:

http://raa.ruby-lang.org/project/bitset/

never used it though...

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