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/* -*- c++ -*- */
/*
* Copyright 2005-2011 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 "throttle_impl.h"
#include <gnuradio/io_signature.h>
#include <cstring>
#include <boost/thread/thread.hpp>
#include <limits>
pmt::pmt_t throttle_rx_rate_pmt(pmt::intern("rx_rate"));
namespace gr {
namespace blocks {
throttle::sptr
throttle::make(size_t itemsize, double samples_per_sec, bool ignore_tags)
{
return gnuradio::get_initial_sptr
(new throttle_impl(itemsize, samples_per_sec, ignore_tags));
}
throttle_impl::throttle_impl(size_t itemsize,
double samples_per_second,
bool ignore_tags)
: sync_block("throttle",
io_signature::make(1, 1, itemsize),
io_signature::make(1, 1, itemsize)),
d_itemsize(itemsize),
d_ignore_tags(ignore_tags)
{
set_sample_rate(samples_per_second);
}
throttle_impl::~throttle_impl()
{
}
bool
throttle_impl::start()
{
d_start = boost::get_system_time();
d_total_samples = 0;
return block::start();
}
void
throttle_impl::set_sample_rate(double rate)
{
//changing the sample rate performs a reset of state params
d_start = boost::get_system_time();
d_total_samples = 0;
d_samps_per_tick = rate/boost::posix_time::time_duration::ticks_per_second();
d_samps_per_us = rate/1e6;
}
double
throttle_impl::sample_rate() const
{
return d_samps_per_us * 1e6;
}
int
throttle_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
// check for updated rx_rate tag
if(!d_ignore_tags){
uint64_t abs_N = nitems_read(0);
std::vector<tag_t> all_tags;
get_tags_in_range(all_tags, 0, abs_N, abs_N + noutput_items);
std::vector<tag_t>::iterator itr;
for(itr = all_tags.begin(); itr != all_tags.end(); itr++) {
if(pmt::eq( (*itr).key, throttle_rx_rate_pmt)){
double new_rate = pmt::to_double( (*itr).value );
set_sample_rate(new_rate);
}
}
}
//calculate the expected number of samples to have passed through
boost::system_time now = boost::get_system_time();
boost::int64_t ticks = (now - d_start).ticks();
uint64_t expected_samps = uint64_t(d_samps_per_tick*ticks);
//if the expected samples was less, we need to throttle back
if(d_total_samples > expected_samps) {
double sleep_time = (d_total_samples - expected_samps)/d_samps_per_us;
if (std::numeric_limits<long>::max() < sleep_time) {
GR_LOG_ALERT(d_logger, "WARNING: Throttle sleep time overflow! You "
"are probably using a very low sample rate.");
}
boost::this_thread::sleep(boost::posix_time::microseconds
(long(sleep_time)));
}
//copy all samples output[i] <= input[i]
const char *in = (const char *)input_items[0];
char *out = (char *)output_items[0];
std::memcpy(out, in, noutput_items * d_itemsize);
d_total_samples += noutput_items;
return noutput_items;
}
void
throttle_impl::setup_rpc()
{
#ifdef GR_CTRLPORT
d_rpc_vars.push_back(
rpcbasic_sptr(new rpcbasic_register_get<throttle, double>(
alias(), "sample_rate", &throttle::sample_rate,
pmt::mp(0.0), pmt::mp(100.0e6), pmt::mp(0.0),
"Hz", "Sample Rate", RPC_PRIVLVL_MIN,
DISPTIME | DISPOPTSTRIP)));
d_rpc_vars.push_back(
rpcbasic_sptr(new rpcbasic_register_set<throttle, double>(
alias(), "sample_rate", &throttle::set_sample_rate,
pmt::mp(0.0), pmt::mp(100.0e6), pmt::mp(0.0),
"Hz", "Sample Rate", RPC_PRIVLVL_MIN,
DISPTIME | DISPOPTSTRIP)));
#endif /* GR_CTRLPORT */
}
} /* namespace blocks */
} /* namespace gr */
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