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/* -*- c++ -*- */
/*
* Copyright 2015 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 <gnuradio/io_signature.h>
#include "atsc_rs_encoder_impl.h"
namespace gr {
namespace dtv {
static const int rs_init_symsize = 8;
static const int rs_init_gfpoly = 0x11d;
static const int rs_init_fcr = 0; // first consecutive root
static const int rs_init_prim = 1; // primitive is 1 (alpha)
static const int rs_init_nroots = 20;
static const int N = (1 << rs_init_symsize) - 1; // 255
static const int K = N - rs_init_nroots; // 235
static const int amount_of_pad = N - ATSC_MPEG_RS_ENCODED_LENGTH; // 48
atsc_rs_encoder::sptr
atsc_rs_encoder::make()
{
return gnuradio::get_initial_sptr
(new atsc_rs_encoder_impl());
}
atsc_rs_encoder_impl::atsc_rs_encoder_impl()
: gr::sync_block("atsc_rs_encoder",
gr::io_signature::make(1, 1, sizeof(atsc_mpeg_packet_no_sync)),
gr::io_signature::make(1, 1, sizeof(atsc_mpeg_packet_rs_encoded)))
{
d_rs = init_rs_char(rs_init_symsize, rs_init_gfpoly, rs_init_fcr, rs_init_prim, rs_init_nroots);
assert (d_rs != 0);
}
atsc_rs_encoder_impl::~atsc_rs_encoder_impl()
{
if (d_rs) {
free_rs_char(d_rs);
}
d_rs = 0;
}
void
atsc_rs_encoder_impl::encode(atsc_mpeg_packet_rs_encoded &out, const atsc_mpeg_packet_no_sync &in)
{
unsigned char tmp[K];
assert((int)(amount_of_pad + sizeof (in.data)) == K);
// add missing prefix zero padding to message
memset(tmp, 0, amount_of_pad);
memcpy(&tmp[amount_of_pad], in.data, sizeof (in.data));
// copy message portion to output packet
memcpy(out.data, in.data, sizeof (in.data));
// now compute parity bytes and add them to tail end of output packet
encode_rs_char(d_rs, tmp, &out.data[sizeof (in.data)]);
}
int
atsc_rs_encoder_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const atsc_mpeg_packet_no_sync *in = (const atsc_mpeg_packet_no_sync *) input_items[0];
atsc_mpeg_packet_rs_encoded *out = (atsc_mpeg_packet_rs_encoded *) output_items[0];
for (int i = 0; i < noutput_items; i++) {
assert(in[i].pli.regular_seg_p());
out[i].pli = in[i].pli; // copy pipeline info...
encode(out[i], in[i]);
}
// Tell runtime system how many output items we produced.
return noutput_items;
}
} /* namespace dtv */
} /* namespace gr */
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