base62.rb

class Base62

  CHARS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
  SIZE = CHARS.size

  def self.short(number)
    return 0 if number == 0
    chars = ''
    while number != 0 do
      number, mod = number.divmod(SIZE)
      chars << CHARS[mod]
    end
    chars.reverse
  end

end