DBC parser initial commit.

dbc.pro

@@ -0,0 +1,18 @@
+TEMPLATE = app
+CONFIG += console c++17
+CONFIG -= app_bundle
+CONFIG -= qt
+
+SOURCES += \
+        dbc_parser.cpp \
+        dbc_tree_builder.cpp \
+        main.cpp \
+        tree_node.cpp
+
+HEADERS += \
+  dbc_database.h \
+  dbc_parser.h \
+  dbc_tree_builder.h \
+  frame_info.h \
+  signal_info.h \
+  tree_node.h

dbc_database.h

@@ -0,0 +1,15 @@
+#ifndef DBC_DATABASE_H
+#define DBC_DATABASE_H
+
+#include <vector>
+
+#include "frame_info.h"
+
+/**
+ * @brief Parsed DBC content stored in a simple internal form.
+ */
+struct DbcDatabase {
+  std::vector<FrameInfo> frames; /**< All frames found in DBC file. */
+};
+
+#endif /* DBC_DATABASE_H */

dbc_parser.cpp

@@ -0,0 +1,315 @@
+#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;
+}

dbc_parser.h

@@ -0,0 +1,51 @@
+#ifndef DBC_PARSER_H
+#define DBC_PARSER_H
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+#include "dbc_database.h"
+
+/**
+ * @brief Minimal DBC parser.
+ *
+ * Supports:
+ * - BO_
+ * - SG_
+ * - CM_ BO_
+ * - CM_ SG_
+ *
+ * Ignores:
+ * - attributes
+ * - multiplexing
+ * - value tables
+ */
+class DbcParser {
+  public:
+    /**
+     * @brief Parse DBC file.
+     * @param filePath Path to input file.
+     * @return Parsed database.
+     * @throws std::runtime_error on file or parse errors.
+     */
+    DbcDatabase ParseFile (const std::string &filePath) const;
+
+  private:
+    static bool IsFrameLine (const std::string &line);
+    static bool IsSignalLine (const std::string &line);
+    static bool IsCommentLine (const std::string &line);
+    static std::string Trim (const std::string &text);
+    static std::vector<std::string> SplitReceivers (const std::string &text);
+    static std::uint32_t TryExtractPgn (std::uint32_t canId, bool &hasPgn);
+
+    static FrameInfo ParseFrameLine (const std::string &line);
+    static SignalInfo ParseSignalLine (const std::string &line);
+
+    static void ParseCommentLine (const std::string &line, DbcDatabase &database);
+
+    static FrameInfo *FindFrameById (DbcDatabase &database, std::uint32_t canId);
+    static SignalInfo *FindSignalByName (FrameInfo &frame, const std::string &signalName);
+};
+
+#endif /* DBC_PARSER_H */

dbc_tree_builder.cpp

@@ -0,0 +1,20 @@
+#include "dbc_tree_builder.h"
+
+std::unique_ptr<TreeNode> DbcTreeBuilder::Build (const DbcDatabase &database) const {
+  std::unique_ptr<TreeNode> root (new TreeNode());
+
+  for (std::size_t frameIndex = 0U; frameIndex < database.frames.size(); ++frameIndex) {
+    const FrameInfo &frame = database.frames[frameIndex];
+    std::unique_ptr<TreeNode> frameNode (new TreeNode (frame));
+
+    for (std::size_t signalIndex = 0U; signalIndex < frame.signals.size(); ++signalIndex) {
+      const SignalInfo &signal = frame.signals[signalIndex];
+      std::unique_ptr<TreeNode> signalNode (new TreeNode (signal));
+      frameNode->AddChild (std::move (signalNode));
+    }
+
+    root->AddChild (std::move (frameNode));
+  }
+
+  return root;
+}

dbc_tree_builder.h

@@ -0,0 +1,22 @@
+#ifndef DBC_TREE_BUILDER_H
+#define DBC_TREE_BUILDER_H
+
+#include <memory>
+
+#include "dbc_database.h"
+#include "tree_node.h"
+
+/**
+ * @brief Builds a simple tree from parsed DBC database.
+ */
+class DbcTreeBuilder {
+  public:
+    /**
+     * @brief Build tree representation of parsed DBC data.
+     * @param database Parsed database.
+     * @return Root node of the tree.
+     */
+    std::unique_ptr<TreeNode> Build (const DbcDatabase &database) const;
+};
+
+#endif /* DBC_TREE_BUILDER_H */

frame_info.h

@@ -0,0 +1,35 @@
+#ifndef FRAME_INFO_H
+#define FRAME_INFO_H
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+#include "signal_info.h"
+
+/**
+ * @brief Describes one CAN frame from a DBC file.
+ */
+struct FrameInfo {
+  std::string name;                  /**< Frame name. */
+  std::uint32_t canId;               /**< Raw CAN identifier from DBC. */
+  std::uint32_t pgn;                 /**< J1939 PGN if applicable. */
+  bool hasPgn;                       /**< true if PGN was derived. */
+  std::uint8_t dlc;                  /**< Frame payload length. */
+  std::string transmitter;           /**< Transmitter ECU name. */
+  std::string comment;               /**< Optional frame comment. */
+  std::vector<SignalInfo> signals;   /**< Signals contained in the frame. */
+
+  FrameInfo()
+    : name()
+    , canId (0U)
+    , pgn (0U)
+    , hasPgn (false)
+    , dlc (0U)
+    , transmitter()
+    , comment()
+    , signals() {
+  }
+};
+
+#endif /* FRAME_INFO_H */

main.cpp

@@ -0,0 +1,99 @@
+#include <iostream>
+#include <memory>
+#include <cstddef>
+
+#include "dbc_parser.h"
+#include "dbc_tree_builder.h"
+#include "tree_node.h"
+
+static void PrintReceivers (const std::vector<std::string> &receivers) {
+  for (std::size_t index = 0U; index < receivers.size(); ++index) {
+    if (index != 0U)
+      std::cout << ",";
+
+    std::cout << receivers[index];
+  }
+}
+
+static void PrintTree (const TreeNode *node, int indent) {
+  if (node == nullptr)
+    return;
+
+  for (int i = 0; i < indent; ++i)
+    std::cout << "  ";
+
+  switch (node->GetType()) {
+    case NodeType::Root:
+      std::cout << "[root] " << node->GetName() << "\n";
+      break;
+
+    case NodeType::Frame: {
+      const FrameInfo *frame = node->GetFrame();
+      std::cout << "[frame] " << node->GetName();
+
+      if (frame != nullptr) {
+        std::cout << " id=" << frame->canId
+                  << " dlc=" << static_cast<unsigned int> (frame->dlc)
+                  << " tx=" << frame->transmitter;
+
+        if (frame->hasPgn)
+          std::cout << " pgn=" << frame->pgn;
+
+        if (!frame->comment.empty())
+          std::cout << " comment=\"" << frame->comment << "\"";
+      }
+
+      std::cout << "\n";
+      break;
+    }
+
+    case NodeType::Signal: {
+      const SignalInfo *signal = node->GetSignal();
+      std::cout << "[signal] " << node->GetName();
+
+      if (signal != nullptr) {
+        std::cout << " start=" << signal->startBit
+                  << " len=" << signal->length
+                  << " unit=" << signal->unit
+                  << " rx=";
+
+        PrintReceivers (signal->receivers);
+
+        if (!signal->comment.empty())
+          std::cout << " comment=\"" << signal->comment << "\"";
+      }
+
+      std::cout << "\n";
+      break;
+    }
+
+    default:
+      std::cout << "[unknown]\n";
+      break;
+  }
+
+  for (std::size_t i = 0U; i < node->GetChildCount(); ++i)
+    PrintTree (node->GetChild (i), indent + 1);
+}
+
+int main (int argc, char *argv[]) {
+  if (argc < 2) {
+    std::cerr << "Usage: dbc_demo <file.dbc>\n";
+    return 1;
+  }
+
+  try {
+    DbcParser parser;
+    DbcDatabase database = parser.ParseFile (argv[1]);
+
+    DbcTreeBuilder builder;
+    std::unique_ptr<TreeNode> root = builder.Build (database);
+
+    PrintTree (root.get(), 0);
+  } catch (const std::exception &ex) {
+    std::cerr << "Error: " << ex.what() << "\n";
+    return 2;
+  }
+
+  return 0;
+}

signal_info.h

@@ -0,0 +1,41 @@
+#ifndef SIGNAL_INFO_H
+#define SIGNAL_INFO_H
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+/**
+ * @brief Describes one signal inside a DBC frame.
+ */
+struct SignalInfo {
+  std::string name;                   /**< Signal name. */
+  std::uint32_t startBit;             /**< Start bit in DBC notation. */
+  std::uint32_t length;               /**< Signal length in bits. */
+  bool isLittleEndian;                /**< true for Intel, false for Motorola. */
+  bool isSigned;                      /**< true if signal is signed. */
+  double factor;                      /**< Scaling factor. */
+  double offset;                      /**< Physical offset. */
+  double minimum;                     /**< Minimum physical value. */
+  double maximum;                     /**< Maximum physical value. */
+  std::string unit;                   /**< Physical unit. */
+  std::vector<std::string> receivers; /**< Receivers of this signal. */
+  std::string comment;                /**< Optional signal comment. */
+
+  SignalInfo()
+    : name()
+    , startBit (0U)
+    , length (0U)
+    , isLittleEndian (true)
+    , isSigned (false)
+    , factor (1.0)
+    , offset (0.0)
+    , minimum (0.0)
+    , maximum (0.0)
+    , unit()
+    , receivers()
+    , comment() {
+  }
+};
+
+#endif /* SIGNAL_INFO_H */

tree_node.cpp

@@ -0,0 +1,64 @@
+#include "tree_node.h"
+
+TreeNode::TreeNode()
+  : m_type (NodeType::Root)
+  , m_name ("dbc")
+  , m_children()
+  , m_frame()
+  , m_signal() {
+}
+
+TreeNode::TreeNode (const FrameInfo &frame)
+  : m_type (NodeType::Frame)
+  , m_name (frame.name)
+  , m_children()
+  , m_frame (new FrameInfo (frame))
+  , m_signal() {
+}
+
+TreeNode::TreeNode (const SignalInfo &signal)
+  : m_type (NodeType::Signal)
+  , m_name (signal.name)
+  , m_children()
+  , m_frame()
+  , m_signal (new SignalInfo (signal)) {
+}
+
+void TreeNode::AddChild (std::unique_ptr<TreeNode> child) {
+  if (child)
+    m_children.push_back (std::move (child));
+}
+
+std::size_t TreeNode::GetChildCount() const {
+  return m_children.size();
+}
+
+const TreeNode *TreeNode::GetChild (std::size_t index) const {
+  if (index >= m_children.size())
+    return nullptr;
+
+  return m_children[index].get();
+}
+
+TreeNode *TreeNode::GetChild (std::size_t index) {
+  if (index >= m_children.size())
+    return nullptr;
+
+  return m_children[index].get();
+}
+
+NodeType TreeNode::GetType() const {
+  return m_type;
+}
+
+const std::string &TreeNode::GetName() const {
+  return m_name;
+}
+
+const FrameInfo *TreeNode::GetFrame() const {
+  return m_frame.get();
+}
+
+const SignalInfo *TreeNode::GetSignal() const {
+  return m_signal.get();
+}

tree_node.h

@@ -0,0 +1,109 @@
+#ifndef TREE_NODE_H
+#define TREE_NODE_H
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <cstddef>
+
+#include "frame_info.h"
+#include "signal_info.h"
+
+/**
+ * @brief Type of a tree node.
+ */
+enum class NodeType {
+  Root,
+  Frame,
+  Signal
+};
+
+/**
+ * @brief Tree node for later use in model/view or other hierarchy consumers.
+ */
+class TreeNode {
+  public:
+    /**
+     * @brief Create root node.
+     */
+    TreeNode();
+
+    /**
+     * @brief Create frame node.
+     * @param frame Frame payload.
+     */
+    explicit TreeNode (const FrameInfo &frame);
+
+    /**
+     * @brief Create signal node.
+     * @param signal Signal payload.
+     */
+    explicit TreeNode (const SignalInfo &signal);
+
+    ~TreeNode() = default;
+
+    TreeNode (const TreeNode &) = delete;
+    TreeNode &operator= (const TreeNode &) = delete;
+
+    TreeNode (TreeNode &&) = default;
+    TreeNode &operator= (TreeNode &&) = default;
+
+    /**
+     * @brief Add child node.
+     * @param child Child node to add.
+     */
+    void AddChild (std::unique_ptr<TreeNode> child);
+
+    /**
+     * @brief Get child count.
+     * @return Number of children.
+     */
+    std::size_t GetChildCount() const;
+
+    /**
+     * @brief Get child by index.
+     * @param index Child index.
+     * @return Child pointer or nullptr if index is invalid.
+     */
+    const TreeNode *GetChild (std::size_t index) const;
+
+    /**
+     * @brief Get mutable child by index.
+     * @param index Child index.
+     * @return Child pointer or nullptr if index is invalid.
+     */
+    TreeNode *GetChild (std::size_t index);
+
+    /**
+     * @brief Get node type.
+     * @return Node type.
+     */
+    NodeType GetType() const;
+
+    /**
+     * @brief Get display name.
+     * @return Node name.
+     */
+    const std::string &GetName() const;
+
+    /**
+     * @brief Get frame payload if node is frame.
+     * @return Pointer to frame info or nullptr.
+     */
+    const FrameInfo *GetFrame() const;
+
+    /**
+     * @brief Get signal payload if node is signal.
+     * @return Pointer to signal info or nullptr.
+     */
+    const SignalInfo *GetSignal() const;
+
+  private:
+    NodeType m_type;
+    std::string m_name;
+    std::vector<std::unique_ptr<TreeNode> > m_children;
+    std::unique_ptr<FrameInfo> m_frame;
+    std::unique_ptr<SignalInfo> m_signal;
+};
+
+#endif /* TREE_NODE_H */