slug.rb

slug.rb

class Slug

  def self.substituion
    {
      '0' => 'c',
      '1' => '0',
      '2' => 'd',
      '3' => '3',
      '4' => 'p',
      '5' => 'e',
      '6' => 'n',
      '7' => '2',
      '8' => '3',
      '9' => '4'
    }
  end

  def self.encode number
    Slug.sub number.to_s, Slug.substituion
  end

  def self.decode value
    Slug.sub value, Slug.substituion.invert
  end

  private

  def self.sub val, from
    out = []
    val.to_s.each_char do |c|
      out << from[c]
    end
    out.join
  end
end