1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
/* -*- 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 <gr_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)
: gr_block("keep_one_in_n",
gr_make_io_signature (1, 1, itemsize),
gr_make_io_signature (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)
n = 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<gr_tag_t> tags;
std::vector<gr_tag_t>::iterator t;
get_tags_in_range(tags, 0, nitems_read(0), nitems_read(0)+ni);
for(t = tags.begin(); t != tags.end(); t++) {
gr_tag_t new_tag = *t;
new_tag.offset *= d_decim_rate;
add_item_tag(0, new_tag);
}
consume_each (ni);
return no;
}
} /* namespace blocks */
} /* namespace gr */
|
