B64.java

    /**
     * Encode the given bytes as a b64 string
     *
     * @param data the data to encode
     * @return the encoded String
     */
    public static String encode(byte[] data) {
        if (data.length % 3 != 0) {
            throw new IllegalArgumentException("Input length not divisible by 3");
        }
        StringBuilder output = new StringBuilder((data.length / 3) * 4);
        for (int i = 0; i < data.length; i += 3) {
            byte b0 = data[i];
            byte b1 = data[i + 1];
            byte b2 = data[i + 2];
            int w = (Byte.toUnsignedInt(b2) << 16) | (Byte.toUnsignedInt(b1) << 8) | Byte.toUnsignedInt(b0);
            // WRONG
            w = (b << 16) | (b1 << 8) | b0
            for (int j = 0; j < 4; j++) {
                output.append(B64_LOOKUP.charAt(w & 0b111111));
                w >>>= 6;
            }
        }
        return output.toString();
    }