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/* -*- c++ -*- */
/*
* Copyright 2006,2010,2012 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 <digital_diff_decoder_bb.h>
#include <gr_io_signature.h>
digital_diff_decoder_bb_sptr
digital_make_diff_decoder_bb (unsigned int modulus)
{
return gnuradio::get_initial_sptr(new digital_diff_decoder_bb(modulus));
}
digital_diff_decoder_bb::digital_diff_decoder_bb (unsigned int modulus)
: gr_sync_block ("diff_decoder_bb",
gr_make_io_signature (1, 1, sizeof (unsigned char)),
gr_make_io_signature (1, 1, sizeof (unsigned char))),
d_modulus(modulus)
{
set_history(2); // need to look at two inputs
}
int
digital_diff_decoder_bb::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const unsigned char *in = (const unsigned char *) input_items[0];
unsigned char *out = (unsigned char *) output_items[0];
in += 1; // ensure that in[-1] is valid
unsigned modulus = d_modulus;
for (int i = 0; i < noutput_items; i++) {
out[i] = (in[i] - in[i-1]) % modulus;
}
return noutput_items;
}
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