can_dbc

Pure Dart DBC file parser and signal compiler for CAN bus databases. Parses standard .dbc files into structured Dart objects and compiles signal definitions to native FFI structs for use with can_engine.

Features

• Full DBC file parsing: messages, signals, nodes, comments, value descriptions
• Standard and extended multiplexing support (M, m<N>, m<N>M)
• Intel (little-endian) and Motorola (big-endian) byte ordering
• Signal compilation to native C structs for zero-copy engine interop
• Extended CAN ID (29-bit) detection
• Validated against real-world DBC corpora (opendbc, j1939_dbc)

Getting started

dependencies:
  can_dbc: ^0.1.0

Usage

Parse a DBC file

import 'package:can_dbc/can_dbc.dart';

void main() async {
  final db = await DbcParser().parseFile('vehicle.dbc');

  print('Version: ${db.version}');
  print('Nodes: ${db.nodes.length}');
  print('Messages: ${db.messages.length}');
  print('Signals: ${db.signalCount}');
}

Parse from a string

final db = DbcParser().parse('''
VERSION "1.0"
BU_: ECU1 ECU2

BO_ 100 EngineData: 8 ECU1
 SG_ EngineSpeed : 0|16@1+ (0.25,0) [0|16383.75] "rpm" ECU2
 SG_ EngineTemp : 16|8@1- (1,-40) [-40|215] "degC" ECU2

CM_ SG_ 100 EngineSpeed "Current engine speed";
VAL_ 100 EngineTemp 0 "Cold" 1 "Normal" 2 "Hot" ;
''');

Access messages and signals

final msg = db.messageById(100)!;
print('${msg.name} from ${msg.transmitter}, ${msg.length} bytes');

for (final sig in msg.signals) {
  print('  ${sig.name}: ${sig.startBit}|${sig.length}'
      ' factor=${sig.factor} offset=${sig.offset}'
      ' [${sig.minimum}..${sig.maximum}] "${sig.unit}"');

  if (sig.valueDescriptions != null) {
    sig.valueDescriptions!.forEach((k, v) => print('    $k = $v'));
  }
}

Multiplexed signals

for (final sig in msg.signals) {
  switch (sig.multiplexType) {
    case MultiplexType.multiplexer:
      print('${sig.name} is the mux selector');
    case MultiplexType.multiplexed:
      print('${sig.name} active when mux == ${sig.multiplexValue}');
    case MultiplexType.extendedMultiplexor:
      print('${sig.name} is a sub-mux (parent=${sig.multiplexValue})');
    case MultiplexType.none:
      break;
  }
}

Compile to native structs (for can_engine)

final compiler = SignalCompiler();
final compiled = compiler.compile(db);

print('${compiled.signalCount} signals, ${compiled.messageCount} messages');

// Pass compiled.signalDefs and compiled.messageDefs to can_engine via FFI.

compiled.dispose(); // Free native memory.

DBC format support

Testing

dart test

# Optional: validate against real-world DBC corpora (requires network)
CAN_DBC_NETWORK_TESTS=1 dart test

License

Apache 2.0 -- see LICENSE for details.