Find all-zero hash

hash-all-zero.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-

class StringAndHash
  def initialize(s, h)
    @string = s
    @hash = h
    @length_zero = (/^0+/ =~ @hash) ? $&.length : 0
  end

  attr_reader :length_zero

  def to_s
    "#{@hash} (#{length_zero}) #{@string}"
  end
end

class HashAllZero
  def initialize(string_init = "a", digest = :md5)
    @string = string_init.dup
    @digest = digest
    @length_max = 0

    require "digest/#{@digest}"
    case @digest
    when :md5
      @dclass = Digest::MD5
    when :sha1
      @dclass = Digest::SHA1
    else
      die "#{@digest}: no such digest name"
    end
  end

  attr_reader :string

  def start
    while true
      d = @dclass.hexdigest(@string)
      if d[0, 1] == "0"
        sh = StringAndHash.new(@string, d)
        if sh.length_zero > @length_max
          puts sh
          @length_max = sh.length_zero
        end
      end
      @string.succ!
    end
  end
end

if __FILE__ == $0
  haz = HashAllZero.new(ARGV.shift || "a")
  while true
    begin
      haz.start
    rescue Interrupt
      puts "[interrupt] trying #{haz.string}"
    end
  end
end

did you succeed tho? :D