portapack-mayhem/firmware/application/app_ais.cpp
2015-12-02 14:05:25 -08:00

379 lines
9.7 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* This program 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 2, or (at your option)
* any later version.
*
* This program 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 this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "app_ais.hpp"
#include "portapack.hpp"
using namespace portapack;
#include "crc.hpp"
#include "string_format.hpp"
namespace baseband {
namespace ais {
struct CRCBitRemap {
size_t operator()(const size_t bit_index) const {
return bit_index;
}
};
using CRCFieldReader = ::FieldReader<std::bitset<1024>, CRCBitRemap>;
struct PacketLengthRange {
constexpr PacketLengthRange(
) : min_bytes { 0 },
max_bytes { 0 }
{
}
constexpr PacketLengthRange(
const uint16_t min_bits,
const uint16_t max_bits
) : min_bytes { static_cast<uint8_t>(min_bits / 8U) },
max_bytes { static_cast<uint8_t>(max_bits / 8U) }
{
// static_assert((min_bits & 7) == 0, "minimum bits not a multiple of 8");
// static_assert((max_bits & 7) == 0, "minimum bits not a multiple of 8");
}
bool contains(const size_t bit_count) const {
return !is_above(bit_count) && !is_below(bit_count);
}
bool is_above(const size_t bit_count) const {
return (min() > bit_count);
}
bool is_below(const size_t bit_count) const {
return (max() < bit_count);
}
size_t min() const {
return min_bytes * 8;
}
size_t max() const {
return max_bytes * 8;
}
private:
const uint8_t min_bytes;
const uint8_t max_bytes;
};
static constexpr std::array<PacketLengthRange, 64> packet_length_range { {
{ 0, 0 }, // 0
{ 168, 168 }, // 1
{ 168, 168 }, // 2
{ 168, 168 }, // 3
{ 168, 168 }, // 4
{ 424, 424 }, // 5
{ 0, 0 }, // 6
{ 0, 0 }, // 7
{ 0, 1008 }, // 8
{ 0, 0 }, // 9
{ 0, 0 }, // 10
{ 0, 0 }, // 11
{ 0, 0 }, // 12
{ 0, 0 }, // 13
{ 0, 0 }, // 14
{ 0, 0 }, // 15
{ 0, 0 }, // 16
{ 0, 0 }, // 17
{ 168, 168 }, // 18
{ 0, 0 }, // 19
{ 72, 160 }, // 20
{ 272, 360 }, // 21
{ 168, 168 }, // 22
{ 160, 160 }, // 23
{ 160, 168 }, // 24
{ 0, 168 }, // 25
{ 0, 0 }, // 26
{ 0, 0 }, // 27
{ 0, 0 }, // 28
{ 0, 0 }, // 29
{ 0, 0 }, // 30
{ 0, 0 }, // 31
} };
struct PacketLengthValidator {
bool operator()(const uint_fast8_t message_id, const size_t length) {
return packet_length_range[message_id].contains(length);
}
};
struct PacketTooLong {
bool operator()(const uint_fast8_t message_id, const size_t length) {
return packet_length_range[message_id].is_below(length);
}
};
struct CRCCheck {
bool operator()(const std::bitset<1024>& payload, const size_t data_length) {
CRCFieldReader field_crc { payload };
CRC<uint16_t> ais_fcs { 0x1021 };
uint16_t crc_calculated = 0xffff;
for(size_t i=0; i<data_length + 16; i+=8) {
if( i == data_length ) {
crc_calculated ^= 0xffff;
}
const uint8_t byte = field_crc.read(i, 8);
crc_calculated = ais_fcs.calculate_byte(crc_calculated, byte);
}
return crc_calculated == 0x0000;
}
};
static std::string format_latlon_normalized(const int32_t normalized) {
const int32_t t = (normalized * 5) / 3;
const int32_t degrees = t / (100 * 10000);
const int32_t fraction = std::abs(t) % (100 * 10000);
return to_string_dec_int(degrees) + "." + to_string_dec_int(fraction, 6, '0');
}
static std::string format_datetime(
const DateTime& datetime
) {
return to_string_dec_uint(datetime.year, 4, '0') + "/" +
to_string_dec_uint(datetime.month, 2, '0') + "/" +
to_string_dec_uint(datetime.day, 2, '0') + " " +
to_string_dec_uint(datetime.hour, 2, '0') + ":" +
to_string_dec_uint(datetime.minute, 2, '0') + ":" +
to_string_dec_uint(datetime.second, 2, '0');
}
static std::string format_navigational_status(const unsigned int value) {
switch(value) {
case 0: return "under way w/engine";
case 1: return "at anchor";
case 2: return "not under command";
case 3: return "restricted maneuv";
case 4: return "constrained draught";
case 5: return "moored";
case 6: return "aground";
case 7: return "fishing";
case 8: return "sailing";
case 9: case 10: case 13: return "reserved";
case 11: return "towing astern";
case 12: return "towing ahead/along";
case 14: return "SART/MOB/EPIRB";
case 15: return "undefined";
default: return "unexpected";
}
}
static char char_to_ascii(const uint8_t c) {
return (c ^ 32) + 32;
}
size_t Packet::length() const {
return payload_length_;
}
bool Packet::is_valid() const {
// Subtract end flag (8 bits) - one unstuffing bit (occurs during end flag).
const size_t data_and_fcs_length = payload_length_ - 7;
if( data_and_fcs_length < 38 ) {
return false;
}
const size_t extra_bits = data_and_fcs_length & 7;
if( extra_bits != 0 ) {
return false;
}
const size_t data_length = data_and_fcs_length - 16;
PacketLengthValidator packet_length_valid;
if( !packet_length_valid(message_id(), data_length) ) {
return false;
}
CRCCheck crc_ok;
if( !crc_ok(payload_, data_length) ) {
return false;
}
return true;
}
uint32_t Packet::message_id() const {
return field_.read(0, 6);
}
uint32_t Packet::source_id() const {
return field_.read(8, 30);
}
uint32_t Packet::read(const size_t start_bit, const size_t length) const {
return field_.read(start_bit, length);
}
std::string Packet::text(
const size_t start_bit,
const size_t character_count
) const {
std::string result;
const size_t character_length = 6;
const size_t end_bit = start_bit + character_count * character_length;
for(size_t i=start_bit; i<end_bit; i+=character_length) {
result += char_to_ascii(field_.read(i, character_length));
}
return result;
}
DateTime Packet::datetime(const size_t start_bit) const {
return {
static_cast<uint16_t>(field_.read(start_bit + 0, 14)),
static_cast<uint8_t >(field_.read(start_bit + 14, 4)),
static_cast<uint8_t >(field_.read(start_bit + 18, 5)),
static_cast<uint8_t >(field_.read(start_bit + 23, 5)),
static_cast<uint8_t >(field_.read(start_bit + 28, 6)),
static_cast<uint8_t >(field_.read(start_bit + 34, 6)),
};
}
Latitude Packet::latitude(const size_t start_bit) const {
// Shifting and dividing is to sign-extend the source field.
// TODO: There's probably a more elegant way to do it.
return static_cast<int32_t>(field_.read(start_bit, 27) << 5) / 32;
}
Longitude Packet::longitude(const size_t start_bit) const {
// Shifting and dividing is to sign-extend the source field.
// TODO: There's probably a more elegant way to do it.
return static_cast<int32_t>(field_.read(start_bit, 28) << 4) / 16;
}
} /* namespace ais */
} /* namespace baseband */
AISModel::AISModel() {
receiver_model.set_baseband_configuration({
.mode = 3,
.sampling_rate = 2457600,
.decimation_factor = 4,
});
receiver_model.set_baseband_bandwidth(1750000);
log_file.open_for_append("ais.txt");
}
bool AISModel::on_packet(const baseband::ais::Packet& packet) {
// TODO: Unstuff here, not in baseband!
if( !packet.is_valid() ) {
return false;
}
if( log_file.is_ready() ) {
std::string entry;
entry.reserve((packet.length() + 3) / 4);
for(size_t i=0; i<packet.length(); i+=4) {
const auto nibble = packet.read(i, 4);
entry += (nibble >= 10) ? ('W' + nibble) : ('0' + nibble);
}
log_file.write_entry(entry);
}
return true;
}
namespace ui {
void AISView::on_show() {
Console::on_show();
auto& message_map = context().message_map();
message_map.register_handler(Message::ID::AISPacket,
[this](Message* const p) {
const auto message = static_cast<const AISPacketMessage*>(p);
const baseband::ais::Packet packet { message->packet.payload, message->packet.bits_received };
if( this->model.on_packet(packet) ) {
this->log(packet);
}
}
);
}
void AISView::on_hide() {
auto& message_map = context().message_map();
message_map.unregister_handler(Message::ID::AISPacket);
Console::on_hide();
}
void AISView::log(const baseband::ais::Packet& packet) {
std::string result { to_string_dec_uint(packet.message_id(), 2) + " " + to_string_dec_uint(packet.source_id(), 10) };
switch(packet.message_id()) {
case 1:
case 2:
case 3:
{
const auto navigational_status = packet.read(38, 4);
result += " " + baseband::ais::format_navigational_status(navigational_status);
result += " " + baseband::ais::format_latlon_normalized(packet.latitude(89));
result += " " + baseband::ais::format_latlon_normalized(packet.longitude(61));
}
break;
case 4:
{
result += " " + baseband::ais::format_datetime(packet.datetime(38));
result += " " + baseband::ais::format_latlon_normalized(packet.latitude(107));
result += " " + baseband::ais::format_latlon_normalized(packet.longitude(79));
}
break;
case 5:
{
const auto call_sign = packet.text(70, 7);
const auto name = packet.text(112, 20);
const auto destination = packet.text(302, 20);
result += " \"" + call_sign + "\" \"" + name + "\" \"" + destination + "\"";
}
break;
case 21:
{
const auto name = packet.text(43, 20);
result += " \"" + name + "\" " + baseband::ais::format_latlon_normalized(packet.latitude(192)) + " " + baseband::ais::format_latlon_normalized(packet.longitude(164));
}
break;
default:
break;
}
writeln(result);
}
} /* namespace ui */