hashname.rb

#!/usr/bin/env ruby

module Hashname
  def self.calc_hashname(name)
    name.chars.inject(5381) do |hash, ch|
      max_int = (hash << 5) + hash + ch.ord
      self.force_overflow_unsigned(max_int)
    end
  end

  def self.force_overflow_unsigned(i)
    i % 2**32 # or equivalently: i & 0xffffffff
  end
end

if __FILE__ == $0
  ARGV.each do |name|
    puts "#{name} = #{Hashname.calc_hashname(name)}"
  end
end