CANParser: parse DBC from stream (commaai#718)

budney · Oct 18, 2022 · c131dce · c131dce
1 parent dde0ff6
commit c131dce
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Showing 2 changed files with 24 additions and 20 deletions.
diff --git a/can/common_dbc.h b/can/common_dbc.h
@@ -72,6 +72,17 @@ struct DBC {
   std::vector<Val> vals;
 };
 
+typedef struct ChecksumState {
+  int checksum_size;
+  int counter_size;
+  int checksum_start_bit;
+  int counter_start_bit;
+  bool little_endian;
+  SignalType checksum_type;
+  unsigned int (*calc_checksum)(uint32_t address, const Signal &sig, const std::vector<uint8_t> &d);
+} ChecksumState;
+
 DBC* dbc_parse(const std::string& dbc_path);
+DBC* dbc_parse_from_stream(const std::string &dbc_name, std::istream &stream, ChecksumState *checksum = nullptr);
 const DBC* dbc_lookup(const std::string& dbc_name);
 std::vector<std::string> get_dbc_names();
diff --git a/can/dbc.cc b/can/dbc.cc
@@ -47,16 +47,6 @@ inline std::string& trim(std::string& s, const char* t = " \t\n\r\f\v") {
   return s.erase(0, s.find_first_not_of(t));
 }
 
-typedef struct ChecksumState {
-  int checksum_size;
-  int counter_size;
-  int checksum_start_bit;
-  int counter_start_bit;
-  bool little_endian;
-  SignalType checksum_type;
-  unsigned int (*calc_checksum)(uint32_t address, const Signal &sig, const std::vector<uint8_t> &d);
-} ChecksumState;
-
 ChecksumState* get_checksum(const std::string& dbc_name) {
   ChecksumState* s = nullptr;
   if (startswith(dbc_name, {"honda_", "acura_"})) {
@@ -107,14 +97,7 @@ void set_signal_type(Signal& s, ChecksumState* chk, const std::string& dbc_name,
   }
 }
 
-DBC* dbc_parse(const std::string& dbc_path) {
-  std::ifstream infile(dbc_path);
-  if (!infile) return nullptr;
-
-  const std::string dbc_name = std::filesystem::path(dbc_path).filename();
-
-  std::unique_ptr<ChecksumState> checksum(get_checksum(dbc_name));
-
+DBC* dbc_parse_from_stream(const std::string &dbc_name, std::istream &stream, ChecksumState *checksum) {
   uint32_t address = 0;
   std::set<uint32_t> address_set;
   std::set<std::string> msg_name_set;
@@ -134,7 +117,7 @@ DBC* dbc_parse(const std::string& dbc_path) {
   int line_num = 0;
   std::smatch match;
   // TODO: see if we can speed up the regex statements in this loop, SG_ is specifically the slowest
-  while (std::getline(infile, line)) {
+  while (std::getline(stream, line)) {
     line = trim(line);
     line_num += 1;
     if (startswith(line, "BO_ ")) {
@@ -168,7 +151,7 @@ DBC* dbc_parse(const std::string& dbc_path) {
       sig.is_signed = match[offset + 5].str() == "-";
       sig.factor = std::stod(match[offset + 6].str());
       sig.offset = std::stod(match[offset + 7].str());
-      set_signal_type(sig, checksum.get(), dbc_name, line_num);
+      set_signal_type(sig, checksum, dbc_name, line_num);
       if (sig.is_little_endian) {
         sig.lsb = sig.start_bit;
         sig.msb = sig.start_bit + sig.size - 1;
@@ -213,6 +196,16 @@ DBC* dbc_parse(const std::string& dbc_path) {
   return dbc;
 }
 
+DBC* dbc_parse(const std::string& dbc_path) {
+  std::ifstream infile(dbc_path);
+  if (!infile) return nullptr;
+
+  const std::string dbc_name = std::filesystem::path(dbc_path).filename();
+
+  std::unique_ptr<ChecksumState> checksum(get_checksum(dbc_name));
+  return dbc_parse_from_stream(dbc_name, infile, checksum.get());
+}
+
 const std::string get_dbc_root_path() {
   char *basedir = std::getenv("BASEDIR");
   if (basedir != NULL) {