91 lines
2.2 KiB
C++
91 lines
2.2 KiB
C++
/* -*- c++ -*- */
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/*
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* Copyright 2019 Thomas Kolb.
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gnuradio/io_signature.h>
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#include "scrambler_impl.h"
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namespace gr {
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namespace hamnet70 {
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scrambler::sptr
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scrambler::make(uint8_t start, uint8_t polynom)
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{
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return gnuradio::get_initial_sptr
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(new scrambler_impl(start, polynom));
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}
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/*
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* The private constructor
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*/
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scrambler_impl::scrambler_impl(uint8_t start, uint8_t polynom)
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: gr::tagged_stream_block("scrambler",
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gr::io_signature::make(1, 1, sizeof(uint8_t)),
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gr::io_signature::make(1, 1, sizeof(uint8_t)), "packet_len"),
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d_start(start),
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d_polynom(polynom)
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{}
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/*
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* Our virtual destructor.
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*/
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scrambler_impl::~scrambler_impl()
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{
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}
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int
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scrambler_impl::calculate_output_stream_length(const gr_vector_int &ninput_items)
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{
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int noutput_items = ninput_items[0];
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return noutput_items ;
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}
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int
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scrambler_impl::work (int noutput_items,
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gr_vector_int &ninput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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const uint8_t *in = (const uint8_t *) input_items[0];
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uint8_t *out = (uint8_t *) output_items[0];
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uint8_t lfsr = d_start;
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for(size_t i = 0; i < noutput_items; i++) {
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*out = *in ^ lfsr;
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if(lfsr & 0x1) {
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lfsr = (lfsr >> 1) ^ d_polynom;
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} else {
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lfsr >>= 1;
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}
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}
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// Tell runtime system how many output items we produced.
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return noutput_items;
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}
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} /* namespace hamnet70 */
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} /* namespace gr */
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