From: Robert Klemme <shortcutter@...>
Date: 2007-01-29T07:30:09+09:00
Subject: Re: "a string".xor("another string")

On 28.01.2007 21:28, Erik Veenstra wrote:
> I want to do an XOR of two strings:
> 
>  "a string".xor("another string")
> 
> It's not that hard to implement, but it's not fast either,
> since it walks through the data string, byte-by-byte.
> 
> Any ideas? For example: "It's memory-hungry!". Any solutions?
> 
> gegroet,
> Erik V. - http://www.erikveen.dds.nl/
> 
> ----------------------------------------------------------------
> 
>  class String
>    def xor(other)
>      if other.empty?
>        self
>      else
>        a1        = self.unpack("c*")
>        a2        = other.unpack("c*")
> 
>        a2 *= 2   while a2.length < a1.length
> 
>        a1.zip(a2).collect{|c1,c2| c1^c2}.pack("c*")
>      end
>    end
>  end
> 
> ----------------------------------------------------------------

irb(main):008:0> a="a string"
=> "a string"
irb(main):009:0> b="another string"
=> "another string"
irb(main):014:0> s="";[a.size, b.size].max.times {|i| s << ((a[i]||0) ^ 
(b[i]||0))}
=> 14
irb(main):015:0> s
=> "\000N\034\000\032\f\034Gstring"

Hm....

	robert