DBC parser initial commit.

This commit is contained in:
2026-03-13 13:00:01 -04:00
parent 4270459973
commit 2a90b2d79d
11 changed files with 789 additions and 0 deletions

315
dbc_parser.cpp Normal file
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#include "dbc_parser.h"
#include <fstream>
#include <sstream>
#include <stdexcept>
#include <algorithm>
#include <cctype>
namespace {
/**
* @brief Remove leading and trailing spaces.
* @param text Input text.
* @return Trimmed text.
*/
std::string TrimText (const std::string &text) {
std::string::size_type begin = 0U;
while ((begin < text.size()) && std::isspace (static_cast<unsigned char> (text[begin])))
++begin;
std::string::size_type end = text.size();
while ((end > begin) && std::isspace (static_cast<unsigned char> (text[end - 1U])))
--end;
return text.substr (begin, end - begin);
}
}
DbcDatabase DbcParser::ParseFile (const std::string &filePath) const {
std::ifstream input (filePath.c_str());
if (!input.is_open())
throw std::runtime_error ("Failed to open DBC file: " + filePath);
DbcDatabase database;
FrameInfo *currentFrame = nullptr;
std::string line;
while (std::getline (input, line)) {
line = Trim (line);
if (line.empty())
continue;
if (IsFrameLine (line)) {
FrameInfo frame = ParseFrameLine (line);
database.frames.push_back (frame);
currentFrame = &database.frames.back();
} else if (IsSignalLine (line)) {
if (currentFrame == nullptr)
throw std::runtime_error ("Signal found before any frame definition.");
SignalInfo signal = ParseSignalLine (line);
currentFrame->signals.push_back (signal);
} else if (IsCommentLine (line))
ParseCommentLine (line, database);
}
return database;
}
bool DbcParser::IsFrameLine (const std::string &line) {
return (line.size() >= 4U) && (line.compare (0U, 4U, "BO_ ") == 0);
}
bool DbcParser::IsSignalLine (const std::string &line) {
return (line.size() >= 4U) && (line.compare (0U, 4U, "SG_ ") == 0);
}
bool DbcParser::IsCommentLine (const std::string &line) {
return (line.size() >= 4U) && (line.compare (0U, 4U, "CM_ ") == 0);
}
std::string DbcParser::Trim (const std::string &text) {
return TrimText (text);
}
std::vector<std::string> DbcParser::SplitReceivers (const std::string &text) {
std::vector<std::string> receivers;
std::string token;
std::istringstream stream (text);
while (std::getline (stream, token, ',')) {
token = TrimText (token);
if (!token.empty())
receivers.push_back (token);
}
return receivers;
}
std::uint32_t DbcParser::TryExtractPgn (std::uint32_t canId, bool &hasPgn) {
hasPgn = false;
/*
* Very simplified J1939 PGN extraction.
* Assumes 29-bit identifier.
*/
if ((canId & 0x1FFFFFFFU) != canId)
return 0U;
const std::uint32_t pf = (canId >> 16U) & 0xFFU;
const std::uint32_t ps = (canId >> 8U) & 0xFFU;
const std::uint32_t dp = (canId >> 24U) & 0x01U;
std::uint32_t pgn = 0U;
if (pf < 240U)
pgn = (dp << 16U) | (pf << 8U);
else
pgn = (dp << 16U) | (pf << 8U) | ps;
hasPgn = true;
return pgn;
}
FrameInfo DbcParser::ParseFrameLine (const std::string &line) {
/*
* Example:
* BO_ 256 EngineData: 8 Vector__XXX
*/
std::istringstream stream (line);
std::string token;
FrameInfo frame;
stream >> token;
if (token != "BO_")
throw std::runtime_error ("Invalid frame line: " + line);
stream >> frame.canId;
stream >> token;
if (token.empty())
throw std::runtime_error ("Missing frame name: " + line);
if (token[token.size() - 1U] == ':')
token.erase (token.size() - 1U, 1U);
frame.name = token;
{
unsigned int dlcValue = 0U;
stream >> dlcValue;
frame.dlc = static_cast<std::uint8_t> (dlcValue);
}
stream >> frame.transmitter;
frame.pgn = TryExtractPgn (frame.canId, frame.hasPgn);
return frame;
}
SignalInfo DbcParser::ParseSignalLine (const std::string &line) {
/*
* Example:
* SG_ EngineSpeed : 0|16@1+ (0.125,0) [0|8000] "rpm" Vector__XXX
*/
SignalInfo signal;
std::string work = TrimText (line);
if (work.compare (0U, 4U, "SG_ ") != 0)
throw std::runtime_error ("Invalid signal line: " + line);
work.erase (0U, 4U);
const std::string::size_type colonPos = work.find (':');
if (colonPos == std::string::npos)
throw std::runtime_error ("Signal line missing ':' : " + line);
signal.name = TrimText (work.substr (0U, colonPos));
std::string rest = TrimText (work.substr (colonPos + 1U));
const std::string::size_type pipePos = rest.find ('|');
const std::string::size_type atPos = rest.find ('@');
const std::string::size_type signPos = rest.find_first_of ("+-", atPos);
const std::string::size_type factorBegin = rest.find ('(');
const std::string::size_type factorComma = rest.find (',', factorBegin);
const std::string::size_type factorEnd = rest.find (')', factorComma);
const std::string::size_type rangeBegin = rest.find ('[');
const std::string::size_type rangeSep = rest.find ('|', rangeBegin);
const std::string::size_type rangeEnd = rest.find (']', rangeSep);
const std::string::size_type unitBegin = rest.find ('"', rangeEnd);
const std::string::size_type unitEnd = rest.find ('"', unitBegin + 1U);
if ((pipePos == std::string::npos) ||
(atPos == std::string::npos) ||
(signPos == std::string::npos) ||
(factorBegin == std::string::npos) ||
(factorComma == std::string::npos) ||
(factorEnd == std::string::npos) ||
(rangeBegin == std::string::npos) ||
(rangeSep == std::string::npos) ||
(rangeEnd == std::string::npos) ||
(unitBegin == std::string::npos) ||
(unitEnd == std::string::npos))
throw std::runtime_error ("Unsupported signal syntax: " + line);
signal.startBit = static_cast<std::uint32_t> (
std::stoul (TrimText (rest.substr (0U, pipePos)))
);
signal.length = static_cast<std::uint32_t> (
std::stoul (TrimText (rest.substr (pipePos + 1U, atPos - pipePos - 1U)))
);
{
if ((atPos + 1U) >= rest.size())
throw std::runtime_error ("Invalid endianness in signal: " + line);
const char endianChar = rest[atPos + 1U];
signal.isLittleEndian = (endianChar == '1');
}
{
const char signChar = rest[signPos];
signal.isSigned = (signChar == '-');
}
signal.factor = std::stod (
TrimText (rest.substr (factorBegin + 1U, factorComma - factorBegin - 1U))
);
signal.offset = std::stod (
TrimText (rest.substr (factorComma + 1U, factorEnd - factorComma - 1U))
);
signal.minimum = std::stod (
TrimText (rest.substr (rangeBegin + 1U, rangeSep - rangeBegin - 1U))
);
signal.maximum = std::stod (
TrimText (rest.substr (rangeSep + 1U, rangeEnd - rangeSep - 1U))
);
signal.unit = rest.substr (unitBegin + 1U, unitEnd - unitBegin - 1U);
{
const std::string receiversText = TrimText (rest.substr (unitEnd + 1U));
signal.receivers = SplitReceivers (receiversText);
}
return signal;
}
void DbcParser::ParseCommentLine (const std::string &line, DbcDatabase &database) {
/*
* Examples:
* CM_ BO_ 256 "Frame comment";
* CM_ SG_ 256 EngineSpeed "Signal comment";
*/
std::istringstream stream (line);
std::string token;
stream >> token;
if (token != "CM_")
return;
stream >> token;
if (token == "BO_") {
std::uint32_t canId = 0U;
stream >> canId;
const std::string::size_type quoteBegin = line.find ('"');
const std::string::size_type quoteEnd = line.rfind ('"');
if ((quoteBegin == std::string::npos) ||
(quoteEnd == std::string::npos) ||
(quoteEnd <= quoteBegin))
return;
FrameInfo *frame = FindFrameById (database, canId);
if (frame != nullptr)
frame->comment = line.substr (quoteBegin + 1U, quoteEnd - quoteBegin - 1U);
} else if (token == "SG_") {
std::uint32_t canId = 0U;
std::string signalName;
stream >> canId;
stream >> signalName;
const std::string::size_type quoteBegin = line.find ('"');
const std::string::size_type quoteEnd = line.rfind ('"');
if ((quoteBegin == std::string::npos) ||
(quoteEnd == std::string::npos) ||
(quoteEnd <= quoteBegin))
return;
FrameInfo *frame = FindFrameById (database, canId);
if (frame != nullptr) {
SignalInfo *signal = FindSignalByName (*frame, signalName);
if (signal != nullptr)
signal->comment = line.substr (quoteBegin + 1U, quoteEnd - quoteBegin - 1U);
}
}
}
FrameInfo *DbcParser::FindFrameById (DbcDatabase &database, std::uint32_t canId) {
for (std::size_t index = 0U; index < database.frames.size(); ++index) {
if (database.frames[index].canId == canId)
return &database.frames[index];
}
return nullptr;
}
SignalInfo *DbcParser::FindSignalByName (FrameInfo &frame, const std::string &signalName) {
for (std::size_t index = 0U; index < frame.signals.size(); ++index) {
if (frame.signals[index].name == signalName)
return &frame.signals[index];
}
return nullptr;
}