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/* -*- c++ -*- */
/*
* Copyright 2007,2010-2012 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "ofdm_insert_preamble_impl.h"
#include <gnuradio/io_signature.h>
#include <stdexcept>
#include <iostream>
#include <string>
namespace gr {
namespace digital {
ofdm_insert_preamble::sptr
ofdm_insert_preamble::make(int fft_length,
const std::vector<std::vector<gr_complex> > &preamble)
{
return gnuradio::get_initial_sptr
(new ofdm_insert_preamble_impl(fft_length, preamble));
}
ofdm_insert_preamble_impl::ofdm_insert_preamble_impl(int fft_length,
const std::vector<std::vector<gr_complex> > &preamble)
: block("ofdm_insert_preamble",
io_signature::make2(1, 2,
sizeof(gr_complex)*fft_length,
sizeof(char)),
io_signature::make2(1, 2,
sizeof(gr_complex)*fft_length,
sizeof(char))),
d_fft_length(fft_length),
d_state(ST_IDLE),
d_nsymbols_output(0),
d_pending_flag(0),
d_preamble(preamble)
{
// sanity check preamble symbols
for(size_t i = 0; i < d_preamble.size(); i++) {
if(d_preamble[i].size() != (size_t) d_fft_length)
throw std::invalid_argument("ofdm_insert_preamble_impl: invalid length for preamble symbol");
}
enter_idle();
}
ofdm_insert_preamble_impl::~ofdm_insert_preamble_impl()
{
}
void
ofdm_insert_preamble_impl::forecast(int noutput_items, gr_vector_int &ninput_items_required)
{
ninput_items_required[0] = noutput_items;
}
int
ofdm_insert_preamble_impl::general_work(int noutput_items,
gr_vector_int &ninput_items_v,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
int ninput_items = ninput_items_v.size() == 2 ?
std::min(ninput_items_v[0], ninput_items_v[1]) : ninput_items_v[0];
const gr_complex *in_sym = (const gr_complex *)input_items[0];
const unsigned char *in_flag = 0;
if(input_items.size() == 2)
in_flag = (const unsigned char*)input_items[1];
gr_complex *out_sym = (gr_complex*)output_items[0];
unsigned char *out_flag = 0;
if(output_items.size() == 2)
out_flag = (unsigned char*)output_items[1];
int no = 0; // number items output
int ni = 0; // number items read from input
#define write_out_flag() \
do { \
if(out_flag) \
out_flag[no] = d_pending_flag; \
d_pending_flag = 0; \
} while(0)
while(no < noutput_items && ni < ninput_items) {
switch(d_state) {
case ST_IDLE:
if(in_flag && in_flag[ni] & 0x1) // this is first symbol of new payload
enter_preamble();
else
ni++; // eat one input symbol
break;
case ST_PREAMBLE:
assert(!in_flag || in_flag[ni] & 0x1);
if(d_nsymbols_output >= (int) d_preamble.size()) {
// we've output all the preamble
enter_first_payload();
}
else {
memcpy(&out_sym[no * d_fft_length],
&d_preamble[d_nsymbols_output][0],
d_fft_length*sizeof(gr_complex));
write_out_flag();
no++;
d_nsymbols_output++;
}
break;
case ST_FIRST_PAYLOAD:
// copy first payload symbol from input to output
memcpy(&out_sym[no * d_fft_length],
&in_sym[ni * d_fft_length],
d_fft_length * sizeof(gr_complex));
write_out_flag();
no++;
ni++;
enter_payload();
break;
case ST_PAYLOAD:
if(in_flag && in_flag[ni] & 0x1) { // this is first symbol of a new payload
enter_preamble();
break;
}
// copy a symbol from input to output
memcpy(&out_sym[no * d_fft_length],
&in_sym[ni * d_fft_length],
d_fft_length * sizeof(gr_complex));
write_out_flag();
no++;
ni++;
break;
default:
std::cerr << "ofdm_insert_preamble_impl: (can't happen) invalid state, resetting\n";
enter_idle();
}
}
consume_each(ni);
return no;
}
void
ofdm_insert_preamble_impl::enter_idle()
{
d_state = ST_IDLE;
d_nsymbols_output = 0;
d_pending_flag = 0;
}
void
ofdm_insert_preamble_impl::enter_preamble()
{
d_state = ST_PREAMBLE;
d_nsymbols_output = 0;
d_pending_flag = 1;
}
void
ofdm_insert_preamble_impl::enter_first_payload()
{
d_state = ST_FIRST_PAYLOAD;
}
void
ofdm_insert_preamble_impl::enter_payload()
{
d_state = ST_PAYLOAD;
}
} /* namespace digital */
} /* namespace gr */
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