/* -*- c++ -*- */
/*
 * Copyright 2013-2014 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 "decoder_impl.h"
#include <gnuradio/io_signature.h>
#include <stdio.h>

namespace gr {
namespace fec {

decoder::sptr decoder::make(generic_decoder::sptr my_decoder,
                            size_t input_item_size,
                            size_t output_item_size)
{
    return gnuradio::get_initial_sptr(
        new decoder_impl(my_decoder, input_item_size, output_item_size));
}

decoder_impl::decoder_impl(generic_decoder::sptr my_decoder,
                           size_t input_item_size,
                           size_t output_item_size)
    : block("fec_decoder",
            io_signature::make(1, 1, input_item_size),
            io_signature::make(1, 1, output_item_size)),
      d_input_item_size(input_item_size),
      d_output_item_size(output_item_size)
{
    set_fixed_rate(true);
    set_relative_rate((uint64_t)my_decoder->get_output_size(),
                      (uint64_t)my_decoder->get_input_size());

    // want to guarantee you have enough to run at least one time...
    // remember! this is not a sync block... set_output_multiple does not
    // actually guarantee the output multiple... it DOES guarantee how many
    // outputs (hence inputs) are made available... this is WEIRD to do in
    // GNU Radio, and the algorithm is sensitive to this value
    set_output_multiple(my_decoder->get_output_size() + (my_decoder->get_history()));
    d_decoder = my_decoder;
}

int decoder_impl::fixed_rate_ninput_to_noutput(int ninput)
{
    return (int)(0.5 + ninput * relative_rate());
}

int decoder_impl::fixed_rate_noutput_to_ninput(int noutput)
{
    return (int)(0.5 + noutput / relative_rate());
}

void decoder_impl::forecast(int noutput_items, gr_vector_int& ninput_items_required)
{
    ninput_items_required[0] = 0.5 + fixed_rate_noutput_to_ninput(noutput_items);
}

int decoder_impl::general_work(int noutput_items,
                               gr_vector_int& ninput_items,
                               gr_vector_const_void_star& input_items,
                               gr_vector_void_star& output_items)
{
    const unsigned char* in = (unsigned char*)input_items[0];
    unsigned char* out = (unsigned char*)output_items[0];

    int outnum = (int)(((1.0 / relative_rate()) * noutput_items) + 0.5);
    int innum =
        (int)(relative_rate() * (ninput_items[0] - d_decoder->get_history()) + 0.5) /
        (output_multiple() - d_decoder->get_history());

    int items = (outnum <= ninput_items[0] - d_decoder->get_history())
                    ? noutput_items / (output_multiple() - d_decoder->get_history())
                    : innum;

    for (int i = 0; i < items; ++i) {
        d_decoder->generic_work(
            (void*)(in + (i * d_decoder->get_input_size() * d_input_item_size)),
            (void*)(out + (i * d_decoder->get_output_size() * d_output_item_size)));

        add_item_tag(0,
                     nitems_written(0) +
                         ((i + 1) * d_decoder->get_output_size() * d_output_item_size),
                     pmt::intern(d_decoder->alias()),
                     pmt::PMT_T,
                     pmt::intern(alias()));
    }

    int consumed = static_cast<int>(
        items / relative_rate() * (output_multiple() - d_decoder->get_history()) + 0.5);
    int returned = items * (output_multiple() - d_decoder->get_history());

    consume_each(consumed);
    return returned;
}

} /* namespace fec */
} /* namespace gr */
