base64 encoding

Base64.groovy

intToBase64 = [
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
]

def encode(InputStream is) {
  int countByte = 2
  int twentyFourBit = 0
  is.each {
    twentyFourBit |= it << (countByte * 8)
    countByte--
    if (countByte == -1) {
      for (int shift = 18; shift >= 0; shift -= 6) {
        print intToBase64[(twentyFourBit >> shift) & 63]
      }
      countByte = 2
      twentyFourBit = 0
    }
  }
  if (countByte != 2) {
    int shift = 18
    for (int i = 0; i < 3 - countByte; i++) {
      print intToBase64[(twentyFourBit >> shift) & 63]
      shift -= 6
    }
    for (int i = countByte; i >= 0; i--) {
      print '='
    }
  }
}
def sc = new Scanner(System.in)
while (true) {
  encode(new ByteArrayInputStream(sc.nextLine().bytes))
  println()
}

3바이트씩 읽어주는 InputStream을 만들면 좋을 것 같다는 피드백을 받음