module Faker::Base58

def self.encode(str)
  alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
  base = alphabet.size
  lv = 0
  str.split('').reverse.each_with_index { |v, i| lv += v.unpack('C')[0] * 256**i }
  ret = +''
  while lv.positive?
    lv, mod = lv.divmod(base)
    ret << alphabet[mod]
  end
  npad = str.match(/^#{0.chr}*/)[0].to_s.size
  '1' * npad + ret.reverse
end