/* -*- c++ -*- */
/*
 * Copyright 2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "random_pdu_impl.h"
#include <gnuradio/blocks/pdu.h>
#include <gnuradio/io_signature.h>

namespace gr {
namespace blocks {

random_pdu::sptr
random_pdu::make(int min_items, int max_items, unsigned char byte_mask, int length_modulo)
{
    return gnuradio::get_initial_sptr(
        new random_pdu_impl(min_items, max_items, byte_mask, length_modulo));
}

random_pdu_impl::random_pdu_impl(int min_items,
                                 int max_items,
                                 unsigned char byte_mask,
                                 int length_modulo)
    : block("random_pdu", io_signature::make(0, 0, 0), io_signature::make(0, 0, 0)),
      d_urange(min_items, max_items),
      d_brange(0, 255),
      d_rvar(d_rng, d_urange),
      d_bvar(d_rng, d_brange),
      d_mask(byte_mask),
      d_length_modulo(length_modulo)
{
    message_port_register_out(pdu::pdu_port_id());
    message_port_register_in(pmt::mp("generate"));
    set_msg_handler(pmt::mp("generate"),
                    boost::bind(&random_pdu_impl::generate_pdu, this, _1));
    if (length_modulo < 1)
        throw std::runtime_error("length_module must be >= 1");
    if (max_items < length_modulo)
        throw std::runtime_error("max_items must be >= to length_modulo");
}

bool random_pdu_impl::start()
{
    output_random();
    return true;
}

void random_pdu_impl::output_random()
{
    // pick a random vector length
    int len = d_rvar();
    len = std::max(d_length_modulo, len - len % d_length_modulo);

    // fill it with random bytes
    std::vector<unsigned char> vec(len);
    for (int i = 0; i < len; i++)
        vec[i] = ((unsigned char)d_bvar()) & d_mask;

    // send the vector
    pmt::pmt_t vecpmt(pmt::make_blob(&vec[0], len));
    pmt::pmt_t pdu(pmt::cons(pmt::PMT_NIL, vecpmt));

    message_port_pub(pdu::pdu_port_id(), pdu);
}

} /* namespace blocks */
} /* namespace gr */
