Method Xor

src/streams.h:420–436

* XOR the contents of this stream with a certain key. * * @param[in] key The key used to XOR the data in this stream. */

     * @param[in] key    The key used to XOR the data in this stream.
     */
    void Xor(const std::vector<unsigned char>& key)
    {
        if (key.size() == 0) {
            return;
        }

        for (size_type i = 0, j = 0; i != size(); i++) {
            vch[i] ^= key[j++];

            // This potentially acts on very many bytes of data, so it's
            // important that we calculate `j`, i.e. the `key` index in this
            // way instead of doing a %, which would effectively be a division
            // for each byte Xor'd -- much slower than need be.
            if (j == key.size())
                j = 0;
        }
    }
};