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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 <ldpc_bit_flip_decoder_impl.h>
#include <math.h>
#include <boost/assign/list_of.hpp>
#include <volk/volk.h>
#include <sstream>
#include <stdio.h>
#include <vector>
namespace gr {
namespace fec {
namespace code {
generic_decoder::sptr
ldpc_bit_flip_decoder::make(const fec_mtrx_sptr mtrx_obj,
unsigned int max_iter)
{
return generic_decoder::sptr
(new ldpc_bit_flip_decoder_impl(mtrx_obj, max_iter));
}
ldpc_bit_flip_decoder_impl::ldpc_bit_flip_decoder_impl(const fec_mtrx_sptr mtrx_obj,
unsigned int max_iter)
: generic_decoder("ldpc_bit_flip_decoder")
{
// FEC matrix object to use for decoding
d_mtrx = mtrx_obj;
d_rate = static_cast<double>(d_mtrx->k())/static_cast<double>(d_mtrx->n());
// Set frame size to k, the # of bits in the information word
// All buffers and settings will be based on this value.
set_frame_size(d_mtrx->k());
// Maximum number of iterations in the decoding algorithm
d_max_iterations = max_iter;
}
ldpc_bit_flip_decoder_impl::~ldpc_bit_flip_decoder_impl()
{
}
int
ldpc_bit_flip_decoder_impl::get_output_size()
{
return d_output_size;
}
int
ldpc_bit_flip_decoder_impl::get_input_size()
{
return d_input_size;
}
bool
ldpc_bit_flip_decoder_impl::set_frame_size(unsigned int frame_size)
{
if(frame_size % d_mtrx->k() != 0) {
GR_LOG_ERROR(d_logger, boost::format("Frame size (%1% bits) must be a "
"multiple of the information word "
"size of the LDPC matrix, %2%") \
% frame_size % (d_mtrx->k()));
throw std::runtime_error("ldpc_bit_flip_decoder: cannot use frame size.");
}
d_output_size = frame_size;
d_input_size = static_cast<int>(round(frame_size / d_rate));
return true;
}
double
ldpc_bit_flip_decoder_impl::rate()
{
return d_rate;
}
void
ldpc_bit_flip_decoder_impl::generic_work(void *inbuffer,
void *outbuffer)
{
// Populate the information word
const float *in = (const float*)inbuffer;
unsigned char *out = (unsigned char*) outbuffer;
int j = 0;
for(int i = 0; i < d_input_size; i+=d_mtrx->n()) {
d_mtrx->decode(&out[j], &in[i], d_mtrx->k(), d_max_iterations);
j += d_mtrx->k();
}
} /* ldpc_bit_flip_decoder_impl::generic_work() */
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
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