mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-12-24 23:09:26 -05:00
AIS: Large refactor to separate packet decode from UI/log formatting.
This commit is contained in:
Jared Boone
parent
4baf2a06f2
commit
b8ee19f8e6
@ -24,7 +24,6 @@
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#include "portapack.hpp"
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using namespace portapack;
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#include "field_reader.hpp"
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#include "crc.hpp"
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// TODO: Move string formatting elsewhere!!!
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@ -33,21 +32,12 @@ using namespace portapack;
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namespace baseband {
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namespace ais {
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decoded_packet packet_decode(const std::bitset<1024>& data, const size_t data_length);
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struct BitRemap {
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size_t operator()(const size_t bit_index) const {
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return bit_index ^ 7;
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}
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};
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struct CRCBitRemap {
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size_t operator()(const size_t bit_index) const {
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return bit_index;
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}
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};
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using FieldReader = ::FieldReader<std::bitset<1024>, BitRemap>;
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using CRCFieldReader = ::FieldReader<std::bitset<1024>, CRCBitRemap>;
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struct PacketLengthRange {
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@ -158,75 +148,16 @@ struct CRCCheck {
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}
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};
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static int32_t ais_latitude_normalized(
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const FieldReader& field,
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const size_t start_bit
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) {
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// Shifting and dividing is to sign-extend the source field.
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// TODO: There's probably a more elegant way to do it.
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return static_cast<int32_t>(field.read(start_bit, 27) << 5) / 32;
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}
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static int32_t ais_longitude_normalized(
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const FieldReader& field,
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const size_t start_bit
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) {
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// Shifting and dividing is to sign-extend the source field.
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// TODO: There's probably a more elegant way to do it.
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return static_cast<int32_t>(field.read(start_bit, 28) << 4) / 16;
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}
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static std::string ais_format_latlon_normalized(const int32_t normalized) {
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static std::string format_latlon_normalized(const int32_t normalized) {
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const int32_t t = (normalized * 5) / 3;
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const int32_t degrees = t / (100 * 10000);
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const int32_t fraction = std::abs(t) % (100 * 10000);
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return ui::to_string_dec_int(degrees) + "." + ui::to_string_dec_int(fraction, 6, '0');
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}
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static std::string ais_format_latitude(
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const FieldReader& field,
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const size_t start_bit
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static std::string format_datetime(
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const DateTime& datetime
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) {
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const auto value = static_cast<int32_t>(field.read(start_bit, 27) << 5) / 32;
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return ais_format_latlon_normalized(value);
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}
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static std::string ais_format_longitude(
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const FieldReader& field,
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const size_t start_bit
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) {
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const auto value = static_cast<int32_t>(field.read(start_bit, 28) << 4) / 16;
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return ais_format_latlon_normalized(value);
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}
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struct ais_datetime {
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uint16_t year;
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uint8_t month;
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uint8_t day;
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uint8_t hour;
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uint8_t minute;
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uint8_t second;
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};
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static ais_datetime ais_get_datetime(
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const FieldReader& field,
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const size_t start_bit
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) {
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return {
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static_cast<uint16_t>(field.read(start_bit + 0, 14)),
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static_cast<uint8_t >(field.read(start_bit + 14, 4)),
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static_cast<uint8_t >(field.read(start_bit + 18, 5)),
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static_cast<uint8_t >(field.read(start_bit + 23, 5)),
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static_cast<uint8_t >(field.read(start_bit + 28, 6)),
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static_cast<uint8_t >(field.read(start_bit + 34, 6)),
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};
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}
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static std::string ais_format_datetime(
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const FieldReader& field,
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const size_t start_bit
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) {
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const auto datetime = ais_get_datetime(field, start_bit);
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return ui::to_string_dec_uint(datetime.year, 4) + "/" +
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ui::to_string_dec_uint(datetime.month, 2, '0') + "/" +
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ui::to_string_dec_uint(datetime.day, 2, '0') + " " +
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@ -235,26 +166,7 @@ static std::string ais_format_datetime(
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ui::to_string_dec_uint(datetime.second, 2, '0');
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}
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static char ais_char_to_ascii(const uint8_t c) {
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return (c ^ 32) + 32;
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}
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static std::string ais_read_text(
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const FieldReader& field,
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const size_t start_bit,
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const size_t character_count
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) {
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std::string result;
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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 += ais_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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static std::string ais_format_navigational_status(const unsigned int value) {
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static std::string format_navigational_status(const unsigned int value) {
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switch(value) {
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case 0: return "under way w/engine";
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case 1: return "at anchor";
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@ -274,80 +186,88 @@ static std::string ais_format_navigational_status(const unsigned int value) {
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}
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}
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decoded_packet packet_decode(const std::bitset<1024>& payload, const size_t payload_length) {
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// TODO: Unstuff here, not in baseband!
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static char char_to_ascii(const uint8_t c) {
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return (c ^ 32) + 32;
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}
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size_t Packet::length() const {
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return payload_length_;
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}
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bool Packet::is_valid() const {
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// Subtract end flag (8 bits) - one unstuffing bit (occurs during end flag).
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const size_t data_and_fcs_length = payload_length - 7;
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const size_t data_and_fcs_length = payload_length_ - 7;
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if( data_and_fcs_length < 38 ) {
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return { "short " + ui::to_string_dec_uint(data_and_fcs_length, 3), "" };
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return false;
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}
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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 { "extra bits " + ui::to_string_dec_uint(data_and_fcs_length, 3), "" };
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return false;
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}
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FieldReader field { payload };
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const auto message_id = field.read(0, 6);
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const size_t data_length = data_and_fcs_length - 16;
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PacketLengthValidator packet_length_valid;
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if( !packet_length_valid(message_id, data_length) ) {
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return { "bad length " + ui::to_string_dec_uint(data_length, 3), "" };
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if( !packet_length_valid(message_id(), data_length) ) {
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return false;
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}
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CRCCheck crc_ok;
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if( !crc_ok(payload, data_length) ) {
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return { "crc", "" };
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if( !crc_ok(payload_, data_length) ) {
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return false;
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}
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const auto source_id = field.read(8, 30);
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std::string result { ui::to_string_dec_uint(message_id, 2) + " " + ui::to_string_dec_uint(source_id, 10) };
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return true;
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}
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switch(message_id) {
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case 1:
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case 2:
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case 3:
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{
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const auto navigational_status = field.read(38, 4);
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result += " " + ais_format_navigational_status(navigational_status);
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result += " " + ais_format_latlon_normalized(ais_latitude_normalized(field, 89));
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result += " " + ais_format_latlon_normalized(ais_longitude_normalized(field, 61));
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}
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break;
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uint32_t Packet::message_id() const {
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return field_.read(0, 6);
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}
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case 4:
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{
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result += " " + ais_format_datetime(field, 38);
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result += " " + ais_format_latlon_normalized(ais_latitude_normalized(field, 107));
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result += " " + ais_format_latlon_normalized(ais_longitude_normalized(field, 79));
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}
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break;
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uint32_t Packet::source_id() const {
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return field_.read(8, 30);
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}
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case 5:
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{
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const auto call_sign = ais_read_text(field, 70, 7);
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const auto name = ais_read_text(field, 112, 20);
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const auto destination = ais_read_text(field, 302, 20);
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result += " \"" + call_sign + "\" \"" + name + "\" \"" + destination + "\"";
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}
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break;
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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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case 21:
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{
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const auto name = ais_read_text(field, 43, 20);
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result += " \"" + name + "\" " + ais_format_latitude(field, 192) + " " + ais_format_longitude(field, 164);
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}
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break;
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default:
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break;
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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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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 { "OK", result };
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return result;
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}
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DateTime Packet::datetime(const size_t start_bit) const {
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return {
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static_cast<uint16_t>(field_.read(start_bit + 0, 14)),
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static_cast<uint8_t >(field_.read(start_bit + 14, 4)),
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static_cast<uint8_t >(field_.read(start_bit + 18, 5)),
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static_cast<uint8_t >(field_.read(start_bit + 23, 5)),
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static_cast<uint8_t >(field_.read(start_bit + 28, 6)),
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static_cast<uint8_t >(field_.read(start_bit + 34, 6)),
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};
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}
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Latitude Packet::latitude(const size_t start_bit) const {
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// Shifting and dividing is to sign-extend the source field.
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// TODO: There's probably a more elegant way to do it.
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return static_cast<int32_t>(field_.read(start_bit, 27) << 5) / 32;
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}
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Longitude Packet::longitude(const size_t start_bit) const {
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// Shifting and dividing is to sign-extend the source field.
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// TODO: There's probably a more elegant way to do it.
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return static_cast<int32_t>(field_.read(start_bit, 28) << 4) / 16;
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}
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} /* namespace ais */
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@ -364,15 +284,27 @@ AISModel::AISModel() {
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log_file.open_for_append("ais.txt");
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}
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baseband::ais::decoded_packet AISModel::on_packet(const AISPacketMessage& message) {
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const auto result = baseband::ais::packet_decode(message.packet.payload, message.packet.bits_received);
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bool AISModel::on_packet(const baseband::ais::Packet& packet) {
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// TODO: Unstuff here, not in baseband!
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if( !packet.is_valid() ) {
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return false;
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}
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if( log_file.is_ready() ) {
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std::string entry = result.first + "/" + result.second + "\r\n";
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std::string entry;
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entry.reserve((packet.length() + 3) / 4);
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for(size_t i=0; i<packet.length(); i+=4) {
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const auto nibble = packet.read(i, 4);
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entry += (nibble >= 10) ? ('W' + nibble) : ('0' + nibble);
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}
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entry += "\r\n";
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log_file.write(entry);
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}
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return result;
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return true;
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}
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namespace ui {
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@ -384,7 +316,10 @@ void AISView::on_show() {
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message_map.register_handler(Message::ID::AISPacket,
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[this](Message* const p) {
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const auto message = static_cast<const AISPacketMessage*>(p);
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this->log(this->model.on_packet(*message));
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const baseband::ais::Packet packet { message->packet.payload, message->packet.bits_received };
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if( this->model.on_packet(packet) ) {
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this->log(packet);
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}
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}
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);
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}
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@ -396,10 +331,50 @@ void AISView::on_hide() {
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Console::on_hide();
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}
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void AISView::log(const baseband::ais::decoded_packet decoded) {
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if( decoded.first == "OK" ) {
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writeln(decoded.second);
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void AISView::log(const baseband::ais::Packet& packet) {
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std::string result { ui::to_string_dec_uint(packet.message_id(), 2) + " " + ui::to_string_dec_uint(packet.source_id(), 10) };
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switch(packet.message_id()) {
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case 1:
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case 2:
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case 3:
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{
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const auto navigational_status = packet.read(38, 4);
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result += " " + baseband::ais::format_navigational_status(navigational_status);
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result += " " + baseband::ais::format_latlon_normalized(packet.latitude(89));
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result += " " + baseband::ais::format_latlon_normalized(packet.longitude(61));
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}
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break;
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case 4:
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{
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result += " " + baseband::ais::format_datetime(packet.datetime(38));
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result += " " + baseband::ais::format_latlon_normalized(packet.latitude(107));
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result += " " + baseband::ais::format_latlon_normalized(packet.longitude(79));
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}
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break;
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case 5:
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{
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const auto call_sign = packet.text(70, 7);
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const auto name = packet.text(112, 20);
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const auto destination = packet.text(302, 20);
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result += " \"" + call_sign + "\" \"" + name + "\" \"" + destination + "\"";
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}
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break;
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case 21:
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{
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const auto name = packet.text(43, 20);
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result += " \"" + name + "\" " + baseband::ais::format_latlon_normalized(packet.latitude(192)) + " " + baseband::ais::format_latlon_normalized(packet.longitude(164));
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}
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break;
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default:
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break;
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}
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writeln(result);
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}
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} /* namespace ui */
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@ -25,14 +25,69 @@
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#include "ui_console.hpp"
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#include "message.hpp"
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#include "log_file.hpp"
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#include "field_reader.hpp"
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#include <cstdint>
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#include <cstddef>
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#include <string>
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#include <bitset>
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#include <utility>
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namespace baseband {
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namespace ais {
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using decoded_packet = std::pair<std::string, std::string>;
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struct BitRemap {
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size_t operator()(const size_t bit_index) const {
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return bit_index ^ 7;
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}
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};
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using FieldReader = ::FieldReader<std::bitset<1024>, BitRemap>;
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struct DateTime {
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uint16_t year;
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uint8_t month;
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uint8_t day;
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uint8_t hour;
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uint8_t minute;
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uint8_t second;
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};
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using Latitude = int32_t;
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using Longitude = int32_t;
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class Packet {
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public:
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constexpr Packet(
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const std::bitset<1024>& payload,
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const size_t payload_length
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) : payload_ { payload },
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payload_length_ { payload_length },
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field_ { payload_ }
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{
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}
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size_t length() const;
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bool is_valid() const;
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uint32_t message_id() const;
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uint32_t source_id() const;
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uint32_t read(const size_t start_bit, const size_t length) const;
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std::string text(const size_t start_bit, const size_t character_count) const;
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DateTime datetime(const size_t start_bit) const;
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Latitude latitude(const size_t start_bit) const;
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Longitude longitude(const size_t start_bit) const;
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private:
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const std::bitset<1024> payload_;
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const size_t payload_length_;
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const FieldReader field_;
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};
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} /* namespace ais */
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} /* namespace baseband */
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@ -41,7 +96,7 @@ class AISModel {
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public:
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AISModel();
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baseband::ais::decoded_packet on_packet(const AISPacketMessage& message);
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bool on_packet(const baseband::ais::Packet& packet);
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private:
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LogFile log_file;
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@ -57,7 +112,7 @@ public:
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private:
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AISModel model;
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void log(const baseband::ais::decoded_packet decoded);
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void log(const baseband::ais::Packet& packet);
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};
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} /* namespace ui */
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