108 lines
2.6 KiB
C++
108 lines
2.6 KiB
C++
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/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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* Copyright (C) 2018 Furrtek
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*
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* This file is part of PortaPack.
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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 2, or (at your option)
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* 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; 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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#include "acars_packet.hpp"
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#include "crc.hpp"
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#include <cstdlib>
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namespace acars {
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size_t Packet::length() const {
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return packet_.size();
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}
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bool Packet::is_valid() const {
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return true; //length_valid() && crc_ok();
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}
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Timestamp Packet::received_at() const {
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return packet_.timestamp();
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}
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uint8_t Packet::block_id() const {
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return field_.read(96, 8);
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}
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std::string Packet::registration_number() const {
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std::string result;
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result.reserve(7);
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const size_t character_length = 8;
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for(size_t i=16; i<(16+7*character_length); i+=character_length) {
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result += (field_.read(i, character_length) & 0x7F);
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}
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return result;
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}
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uint32_t Packet::read(const size_t start_bit, const size_t length) const {
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return field_.read(start_bit, length);
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}
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/*std::string Packet::text(
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const size_t start_bit,
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const size_t character_count
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) const {
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std::string result;
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result.reserve(character_count);
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const size_t character_length = 6;
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const size_t end_bit = start_bit + character_count * character_length;
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for(size_t i=start_bit; i<end_bit; i+=character_length) {
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result += char_to_ascii(field_.read(i, character_length));
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}
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return result;
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}*/
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bool Packet::crc_ok() const {
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CRCReader field_crc { packet_ };
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CRC<16> acars_fcs { 0x1021, 0x0000, 0x0000 };
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for(size_t i=0; i<data_length(); i+=8) {
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acars_fcs.process_byte(field_crc.read(i, 8));
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}
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return (acars_fcs.checksum() == (unsigned)field_crc.read(data_length(), fcs_length));
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}
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size_t Packet::data_and_fcs_length() const {
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return length() - 8;
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}
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size_t Packet::data_length() const {
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return data_and_fcs_length() - fcs_length;
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}
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bool Packet::length_valid() const {
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const size_t extra_bits = data_and_fcs_length() & 7;
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if( extra_bits != 0 ) {
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return false;
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}
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return true;
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}
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} /* namespace ais */
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