RLE圧縮アルゴリズム

def self.decode(bytes, length)

  buf = []

  off = 0

  while buf.size < length

    byte = bytes[off]; off += 1

    if byte >= 0xC0

      len = byte & 0x3F

      byte = bytes[off]; off += 1

      buf += [byte] * len

    else

      buf << byte

    end

  end

  return buf

end

def self.encode(bytes)

  packets = []

  byte0 = bytes[0]

  count = 1

  (1...bytes.size).each do |i|

    byte1 = bytes[i]

    if byte0 == byte1

      count += 1

    else

      packets << [count, byte0]

      byte0 = byte1

      count = 1

    end

  end

  packets << [count, byte0]

  buf = []

  packets.each do |packet|

    cnt = packet[0] / 0x3F

    rem = packet[0] % 0x3F

    buf += [0xC0 | 0x3F, packet[1]] * cnt if cnt > 0

    if rem > 0

      if rem == 1 && packet[1] < 0xC0

        buf += [packet[1]]

      else

        buf += [0xC0 | rem, packet[1]]

      end

    end

  end

  return buf.pack('C*')

end