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/* -*- c++ -*- */
/*
* Copyright 2015 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gnuradio/fec/polar_decoder_sc.h>
#include <gnuradio/io_signature.h>
#include <volk/volk.h>
#include <cmath>
#include <cstdio>
namespace gr {
namespace fec {
namespace code {
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)
{
return generic_decoder::sptr(new polar_decoder_sc(
block_size, num_info_bits, frozen_bit_positions, frozen_bit_values));
}
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)
: polar_decoder_common(
block_size, num_info_bits, frozen_bit_positions, frozen_bit_values)
{
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_decoder(d_u_hat_vec, 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)
{
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 (is_frozen_bit(pos)) {
return next_frozen_bit();
}
return llr_bit_decision(llr);
}
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
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