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/* -*- c++ -*- */
/*
* Copyright 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 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 "keep_one_in_n_impl.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace blocks {
keep_one_in_n::sptr keep_one_in_n::make(size_t itemsize, int n)
{
return gnuradio::get_initial_sptr(new keep_one_in_n_impl(itemsize, n));
}
keep_one_in_n_impl::keep_one_in_n_impl(size_t itemsize, int n)
: block("keep_one_in_n",
io_signature::make(1, 1, itemsize),
io_signature::make(1, 1, itemsize)),
d_count(n)
{
// To avoid bad behavior with using set_relative_rate in this block with
// VERY large values of n, we will keep track of things ourselves. Using
// this to turn off automatic tag propagation, which will be handled
// locally in general_work().
set_tag_propagation_policy(TPP_DONT);
set_n(n);
}
void keep_one_in_n_impl::set_n(int n)
{
if (n < 1) {
throw std::invalid_argument("N must be at least 1.");
}
d_n = n;
d_count = n;
// keep our internal understanding of the relative rate of this block
// don't set the relative rate, though, and we will handle our own
// tag propagation.
d_decim_rate = 1.0 / (float)d_n;
}
int keep_one_in_n_impl::general_work(int noutput_items,
gr_vector_int& ninput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const char* in = (const char*)input_items[0];
char* out = (char*)output_items[0];
size_t item_size = input_signature()->sizeof_stream_item(0);
int ni = 0;
int no = 0;
while (ni < ninput_items[0] && no < noutput_items) {
d_count--;
if (d_count <= 0) {
memcpy(out, in, item_size); // copy 1 item
out += item_size;
no++;
d_count = d_n;
}
in += item_size;
ni++;
}
// Because we have set TPP_DONT, we have to propagate the tags here manually.
// Adjustment of the tag sample value is done using the float d_decim_rate.
std::vector<tag_t> tags;
get_tags_in_range(tags, 0, nitems_read(0), nitems_read(0) + ni);
for (const auto& tag : tags) {
tag_t new_tag = tag;
new_tag.offset *= d_decim_rate;
add_item_tag(0, new_tag);
}
consume_each(ni);
return no;
}
} /* namespace blocks */
} /* namespace gr */
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