From a54dc5bab6cc38513e9732be9f5c2670145b160f Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Sun, 24 Feb 2013 18:55:04 -0500
Subject: blocks: adding threshold, strech, and throttle to gr-blocks.
---
gr-blocks/lib/throttle_impl.cc | 97 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 97 insertions(+)
create mode 100644 gr-blocks/lib/throttle_impl.cc
(limited to 'gr-blocks/lib/throttle_impl.cc')
diff --git a/gr-blocks/lib/throttle_impl.cc b/gr-blocks/lib/throttle_impl.cc
new file mode 100644
index 0000000000..49743e3f26
--- /dev/null
+++ b/gr-blocks/lib/throttle_impl.cc
@@ -0,0 +1,97 @@
+/* -*- 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 <gr_io_signature.h>
+#include <cstring>
+#include <boost/thread/thread.hpp>
+
+namespace gr {
+ namespace blocks {
+
+ throttle::sptr
+ throttle::make(size_t itemsize, double samples_per_sec)
+ {
+ return gnuradio::get_initial_sptr
+ (new throttle_impl(itemsize, samples_per_sec));
+ }
+
+ throttle_impl::throttle_impl(size_t itemsize,
+ double samples_per_second)
+ : gr_sync_block("throttle",
+ gr_make_io_signature(1, 1, itemsize),
+ gr_make_io_signature(1, 1, itemsize)),
+ d_itemsize(itemsize)
+ {
+ set_sample_rate(samples_per_second);
+ }
+
+ throttle_impl::~throttle_impl()
+ {
+ }
+
+ 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)
+ {
+ //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) {
+ boost::this_thread::sleep(boost::posix_time::microseconds
+ (long((d_total_samples - expected_samps)/d_samps_per_us)));
+ }
+
+ //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;
+ }
+
+ } /* namespace blocks */
+} /* namespace gr */
--
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