def nonce_increment(nonce, nlen):
    """
    Increase nonce by 1 in little endian
    From libsodium sodium_increment():
    for (; i < nlen; i++) {
        c += (uint_fast16_t) n[i];
        n[i] = (unsigned char) c;
        c >>= 8;
    }
    :param nonce: string_buffer nonce
    :param nlen: nonce length
    :return: nonce plus by 1
    """
    c = 1
    i = 0
    while i < nlen:
        c += ord(nonce[i])
        nonce[i] = chr(c & 255)
        c >>= 8
        i += 1
    return
