1 /* -*- c++ -*- */
2 /*
3 * Copyright 2006,2010,2012 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include "diff_decoder_bb_impl.h"
28 #include <gnuradio/io_signature.h>
29
30 namespace gr {
31 namespace digital {
make(unsigned int modulus)32 diff_decoder_bb::sptr diff_decoder_bb::make(unsigned int modulus)
33 {
34 return gnuradio::get_initial_sptr(new diff_decoder_bb_impl(modulus));
35 }
36
diff_decoder_bb_impl(unsigned int modulus)37 diff_decoder_bb_impl::diff_decoder_bb_impl(unsigned int modulus)
38 : sync_block("diff_decoder_bb",
39 io_signature::make(1, 1, sizeof(unsigned char)),
40 io_signature::make(1, 1, sizeof(unsigned char))),
41 d_modulus(modulus)
42 {
43 set_history(2); // need to look at two inputs
44 }
45
~diff_decoder_bb_impl()46 diff_decoder_bb_impl::~diff_decoder_bb_impl() {}
47
work(int noutput_items,gr_vector_const_void_star & input_items,gr_vector_void_star & output_items)48 int diff_decoder_bb_impl::work(int noutput_items,
49 gr_vector_const_void_star& input_items,
50 gr_vector_void_star& output_items)
51 {
52 const unsigned char* in = (const unsigned char*)input_items[0];
53 unsigned char* out = (unsigned char*)output_items[0];
54 in += 1; // ensure that in[-1] is valid
55
56 unsigned modulus = d_modulus;
57
58 for (int i = 0; i < noutput_items; i++) {
59 out[i] = (in[i] - in[i - 1]) % modulus;
60 }
61
62 return noutput_items;
63 }
64
65 } /* namespace digital */
66 } /* namespace gr */
67