mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2026-08-22 07:29:03 +00:00
Separate AIS packet and formatting code from app code.
This commit is contained in:
Jared Boone
@@ -21,124 +21,31 @@
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#include "ais_app.hpp"
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#include "string_format.hpp"
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#include "portapack.hpp"
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using namespace portapack;
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#include "crc.hpp"
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#include "string_format.hpp"
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#include <algorithm>
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namespace baseband {
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namespace ais {
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namespace format {
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using CRCFieldReader = ::FieldReader<baseband::Packet, BitRemapNone>;
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struct PacketLengthRange {
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constexpr PacketLengthRange(
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) : min_bytes { 0 },
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max_bytes { 0 }
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{
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}
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constexpr PacketLengthRange(
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const uint16_t min_bits,
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const uint16_t max_bits
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) : min_bytes { static_cast<uint8_t>(min_bits / 8U) },
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max_bytes { static_cast<uint8_t>(max_bits / 8U) }
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{
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// static_assert((min_bits & 7) == 0, "minimum bits not a multiple of 8");
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// static_assert((max_bits & 7) == 0, "minimum bits not a multiple of 8");
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}
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constexpr bool contains(const size_t bit_count) const {
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return !is_above(bit_count) && !is_below(bit_count);
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}
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constexpr bool is_above(const size_t bit_count) const {
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return (min() > bit_count);
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}
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constexpr bool is_below(const size_t bit_count) const {
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return (max() < bit_count);
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}
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constexpr size_t min() const {
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return min_bytes * 8;
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}
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constexpr size_t max() const {
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return max_bytes * 8;
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}
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private:
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const uint8_t min_bytes;
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const uint8_t max_bytes;
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};
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static constexpr std::array<PacketLengthRange, 64> packet_length_range { {
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{ 0, 0 }, // 0
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{ 168, 168 }, // 1
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{ 168, 168 }, // 2
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{ 168, 168 }, // 3
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{ 168, 168 }, // 4
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{ 424, 424 }, // 5
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{ 0, 0 }, // 6
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{ 0, 0 }, // 7
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{ 0, 1008 }, // 8
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{ 0, 0 }, // 9
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{ 0, 0 }, // 10
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{ 0, 0 }, // 11
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{ 0, 0 }, // 12
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{ 0, 0 }, // 13
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{ 0, 0 }, // 14
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{ 0, 0 }, // 15
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{ 0, 0 }, // 16
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{ 0, 0 }, // 17
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{ 168, 168 }, // 18
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{ 0, 0 }, // 19
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{ 72, 160 }, // 20
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{ 272, 360 }, // 21
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{ 168, 168 }, // 22
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{ 160, 160 }, // 23
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{ 160, 168 }, // 24
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{ 0, 168 }, // 25
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{ 0, 0 }, // 26
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{ 0, 0 }, // 27
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{ 0, 0 }, // 28
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{ 0, 0 }, // 29
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{ 0, 0 }, // 30
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{ 0, 0 }, // 31
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} };
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struct PacketLengthValidator {
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constexpr bool operator()(const uint_fast8_t message_id, const size_t length) const {
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return packet_length_range[message_id].contains(length);
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}
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};
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struct PacketTooLong {
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constexpr bool operator()(const uint_fast8_t message_id, const size_t length) const {
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return packet_length_range[message_id].is_below(length);
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}
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};
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static std::string format_latlon_normalized(const int32_t normalized) {
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static std::string 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 to_string_dec_int(degrees) + "." + to_string_dec_int(fraction, 6, '0');
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}
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static std::string format_mmsi(
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const MMSI& mmsi
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static std::string mmsi(
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const baseband::ais::MMSI& mmsi
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) {
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return to_string_dec_uint(mmsi, 9, '0');
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}
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static std::string format_datetime(
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const DateTime& datetime
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static std::string datetime(
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const baseband::ais::DateTime& datetime
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) {
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return to_string_dec_uint(datetime.year, 4, '0') + "/" +
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to_string_dec_uint(datetime.month, 2, '0') + "/" +
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@@ -148,7 +55,7 @@ static std::string format_datetime(
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to_string_dec_uint(datetime.second, 2, '0');
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}
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static std::string format_navigational_status(const unsigned int value) {
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static std::string 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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@@ -168,113 +75,8 @@ static std::string format_navigational_status(const unsigned int value) {
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}
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}
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static constexpr 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 packet_.size();
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}
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bool Packet::is_valid() const {
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return length_valid() && crc_ok();
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}
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rtc::RTC Packet::received_at() const {
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return received_at_;
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}
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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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MMSI Packet::user_id() const {
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return field_.read(8, 30);
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}
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MMSI Packet::source_id() const {
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return field_.read(8, 30);
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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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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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bool Packet::crc_ok() const {
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CRCFieldReader field_crc { packet_ };
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CRC<uint16_t> ais_fcs { 0x1021, 0xffff, 0xffff };
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for(size_t i=0; i<data_length(); i+=8) {
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ais_fcs.process_byte(field_crc.read(i, 8));
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}
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return (ais_fcs.checksum() == 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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// Subtract end flag (8 bits) - one unstuffing bit (occurs during end flag).
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return length() - 7;
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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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const PacketLengthValidator packet_length_valid;
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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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return true;
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}
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} /* namespace format */
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} /* namespace ais */
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} /* namespace baseband */
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AISModel::AISModel() {
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receiver_model.set_baseband_configuration({
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@@ -416,7 +218,7 @@ void AISView::draw_entry(
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Painter& painter,
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const Style& s
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) {
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std::string line = baseband::ais::format_mmsi(entry.mmsi) + " ";
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std::string line = ais::format::mmsi(entry.mmsi) + " ";
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if( !entry.name.empty() ) {
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line += entry.name;
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} else {
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