120 lines
3.5 KiB
C++
120 lines
3.5 KiB
C++
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/* -*- c++ -*- */
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/*
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* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
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*
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* Copyright (C) 2018, Libre Space Foundation <http://librespacefoundation.org/>
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*
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* This program 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 of the License, or
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* (at your option) any later version.
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*
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* This program 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 program. If not, see <http://www.gnu.org/licenses/>.
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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 "decoder_8b10b_impl.h"
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#include <gnuradio/blocks/count_bits.h>
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namespace gr
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{
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namespace satnogs
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{
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decoder_8b10b::sptr
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decoder_8b10b::make (const std::string& control_symbol,
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size_t max_frame_len, int comp_type)
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{
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return gnuradio::get_initial_sptr (
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new decoder_8b10b_impl (control_symbol, max_frame_len, comp_type));
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}
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/*
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* The private constructor
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*/
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decoder_8b10b_impl::decoder_8b10b_impl (const std::string& control_symbol,
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size_t max_frame_len, int comp_type) :
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gr::sync_block ("decoder_8b10b",
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gr::io_signature::make (1, 1, sizeof(char)),
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gr::io_signature::make (0, 0, 0)),
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d_max_frame_len (max_frame_len),
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d_comp_type (comp_type),
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d_control_symbol_pos (0),
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d_control_symbol_neg (0),
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d_data_reg (0)
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{
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message_port_register_out (pmt::mp ("pdu"));
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if (!set_access_code (control_symbol)) {
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GR_LOG_ERROR(d_logger, "control_symbol is not 10 bits");
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throw std::out_of_range ("control_symbol is not 10 bits");
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}
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}
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/*
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* Our virtual destructor.
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*/
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decoder_8b10b_impl::~decoder_8b10b_impl ()
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{
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}
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bool
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decoder_8b10b_impl::set_access_code (const std::string &control_symbol)
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{
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unsigned len = control_symbol.length (); // # of bytes in string
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/* if the control sequence is not 10-bit then throw exception */
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if (len != 10) {
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return false;
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}
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for (size_t i = 0; i < len; i++) {
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d_control_symbol_pos = (d_control_symbol_pos << 1)
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| (control_symbol[i] & 0x1);
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}
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d_control_symbol_neg = ~d_control_symbol_pos;
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return true;
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}
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int
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decoder_8b10b_impl::work (int noutput_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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for (int i = 0; i < noutput_items; i++) {
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d_data_reg = (d_data_reg << 1) | (in[i] & 0x1);
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unsigned long long wrong_bits = (d_data_reg ^ d_control_symbol_pos)
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& 0x3FF;
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unsigned int nwrong = gr::blocks::count_bits64 (wrong_bits);
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if (nwrong <= 1) {
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d_data_reg = 0;
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printf ("Packet found \n");
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}
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//GR_LOG_DEBUG(d_logger, boost::format ("Wrong number: %u") % wrong_bits);
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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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}
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/* namespace satnogs */
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} /* namespace gr */
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