base64

alphabet = ("A".."Z").to_a + ("a".."z").to_a + (0..9).to_a + ["/"] + ["+"]

str = "test222222222222"
output = ""
bits = ""

str.each_byte do |c|
  bitstr =  c.to_s(2).rjust(8, "0")
  bits += bitstr #8 bits long
end

bits.scan( /.{1,6}/).each do |x|
  index = x.ljust(6, "0").to_i(2)
  output += alphabet[ index]
end

unless output.length % 4 == 0
  pad = (output.length / 4 + 1) * 4
  output.ljust( pad, "=")
else
  output
end