build message lookup table in dbc

can/common.h

@@ -92,11 +92,10 @@ class CANPacker {
 private:
   const DBC *dbc = NULL;
   std::map<std::pair<uint32_t, std::string>, Signal> signal_lookup;
-  std::map<uint32_t, Msg> message_lookup;
   std::map<uint32_t, uint32_t> counters;
 
 public:
   CANPacker(const std::string& dbc_name);
-  std::vector<uint8_t> pack(uint32_t address, const std::vector<SignalPackValue> &values);
+  std::pair<uint32_t, std::vector<uint8_t>> pack(const std::string &name_or_address, const std::vector<SignalPackValue> &values);
   Msg* lookup_message(uint32_t address);
 };

can/common.pxd

@@ -71,5 +71,5 @@ cdef extern from "common.h":
     void update_strings(vector[string]&, vector[SignalValue]&, bool) except +
 
   cdef cppclass CANPacker:
-   CANPacker(string)
-   vector[uint8_t] pack(uint32_t, vector[SignalPackValue]&)
+   CANPacker(string) except +
+   pair[uint32_t, vector[uint8_t]] pack(const string&, vector[SignalPackValue]&)

can/common_dbc.h

@@ -1,8 +1,8 @@
 #pragma once
 
-#include <cstddef>
 #include <cstdint>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #define ARRAYSIZE(x) (sizeof(x)/sizeof(x[0]))
@@ -61,6 +61,10 @@ struct DBC {
   std::string name;
   std::vector<Msg> msgs;
   std::vector<Val> vals;
+  std::unordered_map<uint32_t, const Msg*> address_to_msg;
+  std::unordered_map<std::string, const Msg*> name_to_msg;
+
+  const Msg *findMessage(const std::string &name_or_address) const;
 };
 
 typedef struct ChecksumState {

can/dbc.cc

@@ -200,6 +200,8 @@ DBC* dbc_parse_from_stream(const std::string &dbc_name, std::istream &stream, Ch
 
   for (auto& m : dbc->msgs) {
     m.sigs = signals[m.address];
+    dbc->address_to_msg[m.address] = &m;
+    dbc->name_to_msg[m.name] = &m;
   }
   for (auto& v : dbc->vals) {
     v.sigs = signals[v.address];
@@ -256,3 +258,15 @@ std::vector<std::string> get_dbc_names() {
   }
   return dbcs;
 }
+
+const Msg* DBC::findMessage(const std::string& name_or_address) const {
+  auto it = name_to_msg.find(name_or_address);
+  if (it != name_to_msg.end()) return it->second;
+
+  try {
+    uint32_t address = std::stoul(name_or_address);
+    return address_to_msg.at(address);
+  } catch (std::exception& ex) {
+    return nullptr;
+  }
+}

can/packer.cc

@@ -30,19 +30,25 @@ void set_value(std::vector<uint8_t> &msg, const Signal &sig, int64_t ival) {
 
 CANPacker::CANPacker(const std::string& dbc_name) {
   dbc = dbc_lookup(dbc_name);
-  assert(dbc);
+  if (!dbc) {
+    throw std::runtime_error("Can't find DBC: " + dbc_name);
+  }
 
   for (const auto& msg : dbc->msgs) {
-    message_lookup[msg.address] = msg;
     for (const auto& sig : msg.sigs) {
       signal_lookup[std::make_pair(msg.address, std::string(sig.name))] = sig;
     }
   }
   init_crc_lookup_tables();
 }
 
-std::vector<uint8_t> CANPacker::pack(uint32_t address, const std::vector<SignalPackValue> &signals) {
-  std::vector<uint8_t> ret(message_lookup[address].size, 0);
+std::pair<uint32_t, std::vector<uint8_t>> CANPacker::pack(const std::string &name_or_address, const std::vector<SignalPackValue> &signals) {
+  auto msg = dbc->findMessage(name_or_address);
+  if (!msg) {
+    throw std::runtime_error("Can't find message: " + name_or_address);
+  }
+  uint32_t address = msg->address;
+  std::vector<uint8_t> ret(msg->size, 0);
 
   // set all values for all given signal/value pairs
   bool counter_set = false;
@@ -89,10 +95,10 @@ std::vector<uint8_t> CANPacker::pack(uint32_t address, const std::vector<SignalP
     }
   }
 
-  return ret;
+  return std::make_pair(address, ret);
 }
 
 // This function has a definition in common.h and is used in PlotJuggler
 Msg* CANPacker::lookup_message(uint32_t address) {
-  return &message_lookup[address];
+  return (Msg*)dbc->address_to_msg.at(address);
 }

can/packer_pyx.pyx

@@ -1,49 +1,24 @@
 # distutils: language = c++
 # cython: c_string_encoding=ascii, language_level=3
 
-from libc.stdint cimport uint8_t
 from libcpp.vector cimport vector
-from libcpp.map cimport map
-from libcpp.string cimport string
-
 from .common cimport CANPacker as cpp_CANPacker
-from .common cimport dbc_lookup, SignalPackValue, DBC
-
+from .common cimport SignalPackValue
 
 cdef class CANPacker:
-  cdef:
-    cpp_CANPacker *packer
-    const DBC *dbc
-    map[string, int] name_to_address
+  cdef cpp_CANPacker *packer
 
   def __init__(self, dbc_name):
-    self.dbc = dbc_lookup(dbc_name)
-    if not self.dbc:
-      raise RuntimeError(f"Can't lookup {dbc_name}")
-
     self.packer = new cpp_CANPacker(dbc_name)
-    for i in range(self.dbc[0].msgs.size()):
-      msg = self.dbc[0].msgs[i]
-      self.name_to_address[string(msg.name)] = msg.address
 
-  cdef vector[uint8_t] pack(self, addr, values):
+  cpdef make_can_msg(self, name_or_addr, bus, values):
     cdef vector[SignalPackValue] values_thing
     values_thing.reserve(len(values))
     cdef SignalPackValue spv
-
     for name, value in values.iteritems():
       spv.name = name.encode("utf8")
       spv.value = value
       values_thing.push_back(spv)
 
-    return self.packer.pack(addr, values_thing)
-
-  cpdef make_can_msg(self, name_or_addr, bus, values):
-    cdef int addr
-    if isinstance(name_or_addr, int):
-      addr = name_or_addr
-    else:
-      addr = self.name_to_address[name_or_addr.encode("utf8")]
-
-    cdef vector[uint8_t] val = self.pack(addr, values)
-    return [addr, 0, (<char *>&val[0])[:val.size()], bus]
+    ret = self.packer.pack(name_or_addr, values_thing)
+    return [ret.first, 0, (<char *>ret.second.data())[:ret.second.size()], bus]