/* -*- c++ -*- */
/*
 * Copyright 2015,2016 Free Software Foundation, Inc.
 *
 * This 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.
 *
 * This software 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 this software; 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 "dvbt_reed_solomon_enc_impl.h"
#include <gnuradio/io_signature.h>

namespace gr {
namespace dtv {

static const int rs_init_symsize = 8;
static const int rs_init_fcr = 0;  // first consecutive root
static const int rs_init_prim = 1; // primitive is 1 (alpha)

dvbt_reed_solomon_enc::sptr dvbt_reed_solomon_enc::make(
    int p, int m, int gfpoly, int n, int k, int t, int s, int blocks)
{
    return gnuradio::get_initial_sptr(
        new dvbt_reed_solomon_enc_impl(p, m, gfpoly, n, k, t, s, blocks));
}

/*
 * The private constructor
 */
dvbt_reed_solomon_enc_impl::dvbt_reed_solomon_enc_impl(
    int p, int m, int gfpoly, int n, int k, int t, int s, int blocks)
    : block("dvbt_reed_solomon",
            io_signature::make(1, 1, sizeof(unsigned char) * blocks * (k - s)),
            io_signature::make(1, 1, sizeof(unsigned char) * blocks * (n - s))),
      d_n(n),
      d_k(k),
      d_s(s),
      d_blocks(blocks)
{
    d_rs = init_rs_char(rs_init_symsize, gfpoly, rs_init_fcr, rs_init_prim, (n - k));
    if (d_rs == NULL) {
        GR_LOG_FATAL(d_logger, "Reed-Solomon Encoder, cannot allocate memory for d_rs.");
        throw std::bad_alloc();
    }
    // The full input frame size (d_k) (no need to add in d_s, as the block input is the
    // pre-shortedned K)
    d_data = (unsigned char*)malloc(sizeof(unsigned char) * (d_k));
    if (d_data == NULL) {
        GR_LOG_FATAL(d_logger,
                     "Reed-Solomon Encoder, cannot allocate memory for d_data.");
        free_rs_char(d_rs);
        throw std::bad_alloc();
    }
}

/*
 * Our virtual destructor.
 */
dvbt_reed_solomon_enc_impl::~dvbt_reed_solomon_enc_impl()
{
    free(d_data);
    free_rs_char(d_rs);
}

void dvbt_reed_solomon_enc_impl::forecast(int noutput_items,
                                          gr_vector_int& ninput_items_required)
{
    ninput_items_required[0] = noutput_items;
}

void dvbt_reed_solomon_enc_impl::encode(const unsigned char* in, unsigned char* out)
{
    // Shortened Reed-Solomon: prepend zero bytes to message (discarded after encoding)
    std::memset(d_data, 0, d_s);
    // This is the number of data bytes we need from the input stream.
    int shortened_k = d_k - d_s;
    std::memcpy(&d_data[d_s], in, shortened_k);

    // Copy input message to output then append Reed-Solomon bits
    std::memcpy(out, in, shortened_k);
    encode_rs_char(d_rs, d_data, &out[shortened_k]);
}

int dvbt_reed_solomon_enc_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 = (const unsigned char*)input_items[0];
    unsigned char* out = (unsigned char*)output_items[0];
    int j = 0;
    int k = 0;

    for (int i = 0; i < noutput_items * d_blocks; i++) {
        encode(in + j, out + k);
        j += (d_k - d_s);
        k += (d_n - d_s);
    }

    // Tell runtime system how many input items we consumed on
    // each input stream.
    consume_each(noutput_items);

    // Tell runtime system how many output items we produced.
    return noutput_items;
}

} /* namespace dtv */
} /* namespace gr */
