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/* -*- c++ -*- */
/*
* Copyright 2015 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 <gnuradio/io_signature.h>
#include <gnuradio/fec/polar_decoder_sc.h>
#include <volk/volk.h>
#include <cmath>
#include <cstdio>
namespace gr
{
namespace fec
{
generic_decoder::sptr
polar_decoder_sc::make(int block_size, int num_info_bits, std::vector<int> frozen_bit_positions,
std::vector<char> frozen_bit_values, bool is_packed)
{
return generic_decoder::sptr(
new polar_decoder_sc(block_size, num_info_bits, frozen_bit_positions, frozen_bit_values,
is_packed));
}
polar_decoder_sc::polar_decoder_sc(int block_size, int num_info_bits,
std::vector<int> frozen_bit_positions,
std::vector<char> frozen_bit_values, bool is_packed) :
polar_decoder_common(block_size, num_info_bits, frozen_bit_positions, frozen_bit_values, is_packed),
d_frozen_bit_counter(0)
{
d_llr_vec = (float*) volk_malloc(sizeof(float) * block_size * (block_power() + 1), volk_get_alignment());
memset(d_llr_vec, 0, sizeof(float) * block_size * (block_power() + 1));
d_u_hat_vec = (unsigned char*) volk_malloc(block_size * (block_power() + 1), volk_get_alignment());
memset(d_u_hat_vec, 0, sizeof(unsigned char) * block_size * (block_power() + 1));
}
polar_decoder_sc::~polar_decoder_sc()
{
volk_free(d_llr_vec);
volk_free(d_u_hat_vec);
}
void
polar_decoder_sc::generic_work(void* in_buffer, void* out_buffer)
{
const float *in = (const float*) in_buffer;
unsigned char *out = (unsigned char*) out_buffer;
initialize_llr_vector(d_llr_vec, in);
sc_decode(d_llr_vec, d_u_hat_vec);
extract_info_bits(out, d_u_hat_vec);
}
void
polar_decoder_sc::sc_decode(float* llrs, unsigned char* u)
{
d_frozen_bit_counter = 0;
memset(u, 0, sizeof(unsigned char) * block_size() * block_power());
for(int i = 0; i < block_size(); i++){
butterfly(llrs, u, 0, i, i);
u[i] = retrieve_bit_from_llr(llrs[i], i);
}
}
unsigned char
polar_decoder_sc::retrieve_bit_from_llr(float llr, const int pos)
{
if(d_frozen_bit_counter < d_frozen_bit_positions.size() && pos == d_frozen_bit_positions.at(d_frozen_bit_counter)){
return d_frozen_bit_values.at(d_frozen_bit_counter++);
}
return llr_bit_decision(llr);
}
} /* namespace fec */
} /* namespace gr */
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