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/* -*- c++ -*- */
/*
* Copyright 2013-2014 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 "ccsds_decoder_impl.h"
#include <math.h>
#include <boost/assign/list_of.hpp>
#include <volk/volk.h>
#include <sstream>
#include <vector>
#include <iostream>
namespace gr {
namespace fec {
namespace code {
generic_decoder::sptr
ccsds_decoder::make(int frame_size,
int start_state, int end_state,
cc_mode_t mode)
{
return generic_decoder::sptr
(new ccsds_decoder_impl(frame_size, start_state, end_state, mode));
}
ccsds_decoder_impl::ccsds_decoder_impl(int frame_size,
int start_state, int end_state,
cc_mode_t mode)
: generic_decoder("ccsds_decoder"),
d_count(0), d_frame_size(frame_size),
d_mode(mode),
d_start_state_chaining(start_state),
d_start_state_nonchaining(start_state),
d_end_state_nonchaining(end_state)
{
// Set max frame size here; all buffers and settings will be
// based on this value.
d_max_frame_size = frame_size;
set_frame_size(frame_size);
float RATE = 0.5;
float ebn0 = 12.0;
float esn0 = RATE*pow(10.0, ebn0/10.0);
gen_met(d_mettab, 100, esn0, 0.0, 4);
viterbi_chunks_init(d_state0);
viterbi_chunks_init(d_state1);
}
ccsds_decoder_impl::~ccsds_decoder_impl()
{
}
int
ccsds_decoder_impl::get_output_size()
{
// packed bits
return d_frame_size/8;
}
int
ccsds_decoder_impl::get_input_size()
{
if(d_mode == CC_TERMINATED) {
return 2*(d_frame_size + 7 - 1);
}
else {
return 2*d_frame_size;
}
}
int
ccsds_decoder_impl::get_input_item_size()
{
return sizeof(float);
}
int
ccsds_decoder_impl::get_history()
{
if(d_mode == CC_STREAMING) {
return 2*(7 - 1);
}
else {
return 0;
}
}
float
ccsds_decoder_impl::get_shift()
{
return 0.0;
}
const char*
ccsds_decoder_impl::get_input_conversion()
{
return "none";
}
const char*
ccsds_decoder_impl::get_output_conversion()
{
return "unpack";
}
bool
ccsds_decoder_impl::set_frame_size(unsigned int frame_size)
{
bool ret = true;
if(frame_size > d_max_frame_size) {
GR_LOG_INFO(d_logger, boost::format("tried to set frame to %1%; max possible is %2%") \
% frame_size % d_max_frame_size);
frame_size = d_max_frame_size;
ret = false;
}
d_frame_size = frame_size;
return ret;
}
double
ccsds_decoder_impl::rate()
{
return 0.5;
}
void
ccsds_decoder_impl::generic_work(void *inbuffer, void *outbuffer)
{
const float *in = (const float*)inbuffer;
unsigned char *out = (unsigned char*)outbuffer;
switch(d_mode) {
case(CC_STREAMING):
for(unsigned int i = 0; i < d_frame_size*2; i++) {
// Translate and clip [-1.0..1.0] to [28..228]
float sample = in[i]*100.0+128.0;
if(sample > 255.0)
sample = 255.0;
else if(sample < 0.0)
sample = 0.0;
d_viterbi_in[d_count % 4] = (unsigned char)(floorf(sample));
if((d_count % 4) == 3) {
// Every fourth symbol, perform butterfly operation
viterbi_butterfly2(d_viterbi_in, d_mettab, d_state0, d_state1);
// Every sixteenth symbol, read out a byte
if(d_count % 16 == 11) {
unsigned char tmp;
viterbi_get_output(d_state0, out++);
viterbi_get_output(d_state0, &tmp);
}
}
d_count++;
}
break;
default:
throw std::runtime_error("ccsds_decoder: mode not recognized");
}
}
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
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