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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_common.h>
#include <volk/volk.h>
#include <gnuradio/blocks/pack_k_bits.h>
#include <gnuradio/blocks/unpack_k_bits.h>
#include <cmath>
#include <stdexcept>
#include <iostream>
#include <vector>
namespace gr {
namespace fec {
namespace code {
polar_common::polar_common(int block_size, int num_info_bits,
std::vector<int> frozen_bit_positions,
std::vector<char> frozen_bit_values) :
d_frozen_bit_positions(frozen_bit_positions), d_frozen_bit_values(frozen_bit_values),
d_block_size(block_size), d_block_power((int) log2(float(block_size))),
d_num_info_bits(num_info_bits)
{
if(pow(2, d_block_power) != d_block_size){
throw std::runtime_error("block_size MUST be a power of 2!");
}
unsigned int num_frozen_bits = d_block_size - d_num_info_bits;
if(num_frozen_bits != d_frozen_bit_positions.size()){
throw std::runtime_error(
"number of frozen bit positions must equal block_size - num_info_bits");
}
// According to papers frozen bits default to '0'.
while(d_frozen_bit_values.size() < num_frozen_bits){
d_frozen_bit_values.push_back(0);
}
initialize_info_bit_position_vector();
setup_volk_vectors();
setup_info_bit_positions_reversed();
d_unpacker = new gr::blocks::kernel::unpack_k_bits(8);
}
void
polar_common::initialize_info_bit_position_vector()
{
int num_frozen_bit = 0;
int frozen_pos = d_frozen_bit_positions.at(num_frozen_bit);
for(int i = 0; i < d_block_size; i++) {
if(i != frozen_pos) {
d_info_bit_positions.push_back((int) i);
}
else {
num_frozen_bit++;
num_frozen_bit = std::min(num_frozen_bit, (int) (d_frozen_bit_positions.size() - 1));
frozen_pos = d_frozen_bit_positions.at(num_frozen_bit);
}
}
if((int) d_info_bit_positions.size() != num_info_bits()) {
throw std::runtime_error("polar_common: number of info bit positions MUST equal num_info_bits (K)!");
}
}
void
polar_common::setup_info_bit_positions_reversed()
{
for(unsigned int i = 0; i < d_info_bit_positions.size(); i++){
d_info_bit_positions_reversed.push_back((int) bit_reverse((long) d_info_bit_positions.at(i), block_power()));
}
if((int) d_info_bit_positions_reversed.size() != num_info_bits()) {
throw std::runtime_error("polar_encoder: number of info bit positions MUST equal num_info_bits (K)!");
}
}
void
polar_common::setup_volk_vectors()
{
int nfrozen = block_size() - num_info_bits();
d_volk_temp = (unsigned char*) volk_malloc(sizeof(unsigned char) * block_size(), volk_get_alignment());
d_volk_frozen_bit_mask = (unsigned char*) volk_malloc(sizeof(unsigned char) * block_size(), volk_get_alignment());
d_volk_frozen_bits = (unsigned char*) volk_malloc(sizeof(unsigned char) * nfrozen, volk_get_alignment());
std::copy(d_frozen_bit_values.begin(), d_frozen_bit_values.end(), d_volk_frozen_bits);
std::fill(d_volk_frozen_bits + d_frozen_bit_values.size(), d_volk_frozen_bits + nfrozen, 0);
int nfbit = 0;
for(int i = 0; i < block_size(); i++){
unsigned char m = 0x00;
if(nfbit < d_frozen_bit_positions.size() && d_frozen_bit_positions[nfbit] == i){
m = 0xFF;
nfbit++;
}
d_volk_frozen_bit_mask[i] = m;
}
}
void
polar_common::volk_encode(unsigned char* out_buf, const unsigned char* in_buf)
{
volk_8u_x3_encodepolar_8u_x2(out_buf, d_volk_temp, d_volk_frozen_bit_mask, d_volk_frozen_bits, in_buf, block_size());
}
void
polar_common::volk_encode_block(unsigned char* out_buf, unsigned char* in_buf)
{
volk_8u_x2_encodeframepolar_8u(out_buf, in_buf, block_size());
}
polar_common::~polar_common()
{
delete d_unpacker;
volk_free(d_volk_temp);
volk_free(d_volk_frozen_bit_mask);
volk_free(d_volk_frozen_bits);
}
long
polar_common::bit_reverse(long value, int active_bits) const
{
long r = 0;
for(int i = 0; i < active_bits; i++) {
r <<= 1;
r |= value & 1;
value >>= 1;
}
return r;
}
void
polar_common::print_packed_bit_array(const unsigned char* printed_array,
const int num_bytes) const
{
int num_bits = num_bytes << 3;
unsigned char* temp = new unsigned char[num_bits];
d_unpacker->unpack(temp, printed_array, num_bytes);
std::cout << "[";
for(int i = 0; i < num_bits; i++) {
std::cout << (int) *(temp + i) << " ";
}
std::cout << "]" << std::endl;
delete [] temp;
}
void
polar_common::print_unpacked_bit_array(const unsigned char* bits,
const unsigned int num_bytes) const
{
std::cout << "( ";
for(unsigned int i = 0; i < num_bytes; i++){
std::cout << (int) *bits++ << ", ";
}
std::cout << ")" << std::endl;
}
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
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