URL shortner

url_shortner.rb

# -*- encoding : utf-8 -*-
require 'digest/md5'

module UrlShorter
  
  ALPHABET = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".split(//)

  def self.short!(url)
    
    hex = Digest::MD5.hexdigest(url)
    hexlen = hex.length
    subhexlen = hexlen / 8 
    
    output = []
    
    for i in 0..subhexlen-1
      subhex = hex[i*8,8]
      int = 0x3FFFFFFF & ("0x#{subhex}".to_i(16))
      out = ""
      
      for j in 0..5
        val = 0x0000001F & int
        int = int >> 5
        out += ALPHABET[val]
      end
      
      output << out
    end
  
    return output[0]
  end
end