Added decoding support to runtime decode.

dbc_parser.cpp

@@ -3,7 +3,6 @@
 #include <fstream>
 #include <sstream>
 #include <stdexcept>
-#include <algorithm>
 #include <cctype>
 
 namespace {
@@ -14,11 +13,13 @@ namespace {
    */
   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])))
+    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])))
+    while ((end > begin) &&
+           std::isspace (static_cast<unsigned char> (text[end - 1U])))
       --end;
 
     return text.substr (begin, end - begin);
@@ -86,13 +87,29 @@ std::vector<std::string> DbcParser::SplitReceivers (const std::string &text) {
   return receivers;
 }
 
-std::uint32_t DbcParser::TryExtractPgn (std::uint32_t canId, bool &hasPgn) {
+void DbcParser::NormalizeCanId (std::uint32_t rawCanId,
+                                std::uint32_t &normalizedCanId,
+                                bool &isExtended) {
+  /*
+   * DBC commonly stores extended identifiers with bit 31 set.
+   * Example:
+   * raw id = 0x80000000 | actual_29_bit_id
+   */
+  if ((rawCanId & 0x80000000U) != 0U) {
+    isExtended = true;
+    normalizedCanId = (rawCanId & 0x1FFFFFFFU);
+  } else {
+    isExtended = (rawCanId > 0x7FFU);
+    normalizedCanId = rawCanId;
+  }
+}
+
+std::uint32_t DbcParser::TryExtractPgn (std::uint32_t canId, bool isExtended, bool &hasPgn) {
   hasPgn = false;
 
-  /*
-   * Very simplified J1939 PGN extraction.
-   * Assumes 29-bit identifier.
-   */
+  if (!isExtended)
+    return 0U;
+
   if ((canId & 0x1FFFFFFFU) != canId)
     return 0U;
 
@@ -114,20 +131,22 @@ std::uint32_t DbcParser::TryExtractPgn (std::uint32_t canId, bool &hasPgn) {
 FrameInfo DbcParser::ParseFrameLine (const std::string &line) {
   /*
    * Example:
-   * BO_ 256 EngineData: 8 Vector__XXX
+   * BO_ 256 EngineData: 8 EEC1
    */
 
   std::istringstream stream (line);
   std::string token;
   FrameInfo frame;
+  std::uint32_t rawCanId = 0U;
 
   stream >> token;
   if (token != "BO_")
     throw std::runtime_error ("Invalid frame line: " + line);
 
-  stream >> frame.canId;
-  stream >> token;
+  stream >> rawCanId;
+  NormalizeCanId (rawCanId, frame.canId, frame.isExtended);
 
+  stream >> token;
   if (token.empty())
     throw std::runtime_error ("Missing frame name: " + line);
 
@@ -143,7 +162,7 @@ FrameInfo DbcParser::ParseFrameLine (const std::string &line) {
   }
 
   stream >> frame.transmitter;
-  frame.pgn = TryExtractPgn (frame.canId, frame.hasPgn);
+  frame.pgn = TryExtractPgn (frame.canId, frame.isExtended, frame.hasPgn);
 
   return frame;
 }
@@ -151,7 +170,7 @@ FrameInfo DbcParser::ParseFrameLine (const std::string &line) {
 SignalInfo DbcParser::ParseSignalLine (const std::string &line) {
   /*
    * Example:
-   * SG_ EngineSpeed : 0|16@1+ (0.125,0) [0|8000] "rpm" Vector__XXX
+   * SG_ EngineSpeed : 0|16@1+ (0.125,0) [0|8000] "rpm" ECU1,ECU2
    */
 
   SignalInfo signal;
@@ -258,8 +277,12 @@ void DbcParser::ParseCommentLine (const std::string &line, DbcDatabase &database
   stream >> token;
 
   if (token == "BO_") {
+    std::uint32_t rawCanId = 0U;
     std::uint32_t canId = 0U;
-    stream >> canId;
+    bool isExtended = false;
+
+    stream >> rawCanId;
+    NormalizeCanId (rawCanId, canId, isExtended);
 
     const std::string::size_type quoteBegin = line.find ('"');
     const std::string::size_type quoteEnd = line.rfind ('"');
@@ -269,16 +292,20 @@ void DbcParser::ParseCommentLine (const std::string &line, DbcDatabase &database
         (quoteEnd <= quoteBegin))
       return;
 
-    FrameInfo *frame = FindFrameById (database, canId);
+    FrameInfo *frame = FindFrameById (database, canId, isExtended);
     if (frame != nullptr)
       frame->comment = line.substr (quoteBegin + 1U, quoteEnd - quoteBegin - 1U);
   } else if (token == "SG_") {
+    std::uint32_t rawCanId = 0U;
     std::uint32_t canId = 0U;
+    bool isExtended = false;
     std::string signalName;
 
-    stream >> canId;
+    stream >> rawCanId;
     stream >> signalName;
 
+    NormalizeCanId (rawCanId, canId, isExtended);
+
     const std::string::size_type quoteBegin = line.find ('"');
     const std::string::size_type quoteEnd = line.rfind ('"');
 
@@ -287,7 +314,7 @@ void DbcParser::ParseCommentLine (const std::string &line, DbcDatabase &database
         (quoteEnd <= quoteBegin))
       return;
 
-    FrameInfo *frame = FindFrameById (database, canId);
+    FrameInfo *frame = FindFrameById (database, canId, isExtended);
     if (frame != nullptr) {
       SignalInfo *signal = FindSignalByName (*frame, signalName);
       if (signal != nullptr)
@@ -296,9 +323,12 @@ void DbcParser::ParseCommentLine (const std::string &line, DbcDatabase &database
   }
 }
 
-FrameInfo *DbcParser::FindFrameById (DbcDatabase &database, std::uint32_t canId) {
+FrameInfo *DbcParser::FindFrameById (DbcDatabase &database,
+                                     std::uint32_t canId,
+                                     bool isExtended) {
   for (std::size_t index = 0U; index < database.frames.size(); ++index) {
-    if (database.frames[index].canId == canId)
+    if ((database.frames[index].canId == canId) &&
+        (database.frames[index].isExtended == isExtended))
       return &database.frames[index];
   }