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https://github.com/xR3b0rn/dbcppp
C/C++ DBC file parser/tool
https://github.com/xR3b0rn/dbcppp
command-line-tool dbc kcd parser
Last synced: 27 days ago
JSON representation
C/C++ DBC file parser/tool
- Host: GitHub
- URL: https://github.com/xR3b0rn/dbcppp
- Owner: xR3b0rn
- License: mit
- Created: 2019-04-14T14:57:38.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-07-24T09:01:30.000Z (5 months ago)
- Last Synced: 2024-08-04T04:07:37.895Z (4 months ago)
- Topics: command-line-tool, dbc, kcd, parser
- Language: C++
- Homepage:
- Size: 9.85 MB
- Stars: 222
- Watchers: 12
- Forks: 71
- Open Issues: 20
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-canbus - dbcppp - C/C++ DBC file parser/tool. (CAN Database / DBC only)
README
[
# dbcppp
A C/C++ DBC file parser based on `boost.spirit`. This library is designed for decoding performance.
# Features
* very fast decoding
* verbose parser output in error case
* DBC is editable through C/C++ interface exported from the library
* read/write DBC file
* decode functionality for frames of arbitrarily byte length
* [cantools](https://github.com/eerimoq/cantools) like decoding
* [KCD](https://github.com/julietkilo/kcd) file format support
# Getting started
## Build & Install
```
git clone --recurse-submodules https://github.com/xR3b0rn/dbcppp.git
cd dbcppp
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j
make RunTests
make install
ldconfig # on Unix-systems only
```
# Usage example
## Command line tool
### dbc2
```
# generate C source from DBC/KCD
dbcparser dbc2 --dbc=file.dbc --format=C
# beauty or merge DBC/KCD
dbcparser dbc2 --dbc=file1.dbc --dbc=file2.kcd --format=DBC
# print DBC/KCD in human readable format
dbcparser dbc2 --dbc=file1.dbc --dbc=file2.kcd --format=human
```
### decode
[cantools](https://github.com/eerimoq/cantools) like decoding:
```
candump any | dbcppp decode --bus=vcan0,file1.dbc --bus=vcan1,file2.dbc
```
## Library
* [Examples](https://github.com/xR3b0rn/dbcppp/tree/master/examples)
* `C++`
```C++
#include
#include
int main()
{
std::unique_ptr net;
{
std::ifstream idbc("your.dbc");
net = dbcppp::INetwork::LoadDBCFromIs(idbc);
}
std::unordered_map messages;
for (const dbcppp::IMessage& msg : net->Messages())
{
messages.insert(std::make_pair(msg.Id(), &msg));
}
can_frame frame;
while (1)
{
receive_frame_data(&frame);
auto iter = messages.find(frame.can_id);
if (iter != messages.end())
{
const dbcppp::IMessage* msg = iter->second;
std::cout << "Received Message: " << msg->Name() << "\n";
for (const dbcppp::ISignal& sig : msg->Signals())
{
const dbcppp::ISignal* mux_sig = msg->MuxSignal();
if (sig.MultiplexerIndicator() != dbcppp::ISignal::EMultiplexer::MuxValue ||
(mux_sig && mux_sig->Decode(frame.data) == sig.MultiplexerSwitchValue()))
{
std::cout << "\t" << sig.Name() << "=" << sig.RawToPhys(sig.Decode(frame.data)) << sig.Unit() << "\n";
}
}
}
}
}
```
* `C`
```C
#include
#include
int main()
{
const dbcppp_Nework* net = dbcppp_NetworkLoadDBCFromFile("your.dbc");
if (net)
{
can_frame frame;
while (1)
{
receive_can_frame_from_somewhere(&frame);
const dbcppp_Message* msg = nullptr;
auto n_msgs = dbcppp_NetworkMessages_Size(net);
for (uint64_t i = 0; i < n_msgs; i++)
{
const dbcppp_Message* msg = dbcppp_NetworkMessages_Get(i);
if (dbcppp_MessageId(tmp) == frame.can_id)
{
printf("Received message: %s\n", dbcppp_MessageGetName(msg));
dbcppp_MessageForEachSignal(msg, print_signal_data, &frame);
for (uint64_t i = 0; i < dbcppp_MessageSignals_Size(msg); i++)
{
const dbcppp_Signal* sig = dbcppp_MessageSignals_Get(msg, i);
uint64_t raw = dbcppp_SignalDecode(sig, frame.data);
double phys = dbcppp_SignalRawToPhys(sig, raw);
printf("\t%s=%f\n", dbcppp_SignalName(sig), phys);
}
}
}
}
}
dbcppp_NetworkFree(net);
}
```
# DBC data types
## Supported
* version
* new_symbols
* bit_timing
* nodes
* value_tables
* messages
* message_transmitters
* environment_variables
* environment_variables_data
* signal_types
* comments
* attribute_definitions
* attribute_defaults
* attribute_values
* value_descriptions
* signal_extended_value_type_list
* signal_groups
* signal_multiplexer_value
## Not supported yet
* sigtype_attr_list
* signal_type_refs
# Decode-function
The signals decode function is using prestored masks and fixed offsets to speed up calculation, therefore the decoding-function should be almost as fast as a code generated decode function would be. The assembly of the `decode`-function on its critical path (signed and byte swap must happen) looks like this (VS19 10.0.18362.0 compiler):
```
template
double template_decode(const Signal* sig, const void* nbytes) noexcept
00007FF8025BCA73 mov rax,rcx
00007FF8025BCA76 mov rcx,qword ptr [rcx+140h]
00007FF8025BCA7D xorps xmm0,xmm0
00007FF8025BCA80 bswap r8
00007FF8025BCA83 shr r8,cl
00007FF8025BCA86 and r8,qword ptr [rax+130h]
00007FF8025BCA8D mov rcx,qword ptr [rax+138h]
00007FF8025BCA94 mov rax,rcx
00007FF8025BCA97 or rcx,r8
00007FF8025BCA9A and rax,r8
00007FF8025BCA9D cmove rcx,r8
00007FF8025BCAA1 cvtsi2sd xmm0,rcx
00007FF8025BCAA6 ret
```
On the best path (no byteswap must take place and ExtendedValueType == Double) the decode function only has 5 instructions:
```
template
double template_decode(const Signal* sig, const void* nbytes) noexcept
00007FF8025BCAF0 mov rax,qword ptr [rdx]
00007FF8025BCAF3 mov qword ptr [rsp+8],rcx
00007FF8025BCAF8 mov qword ptr [sig],rax
00007FF8025BCAFD movsd xmm0,mmword ptr [data]
00007FF8025BCB03 ret
```
# Known issues
* tests for decoding function for float/double is failing on some machines (currently only confirmed for System/s390x)
# Similar projects
* [Vector_DBC](https://bitbucket.org/tobylorenz/vector_dbc/src/master/) Does basically the same, the biggest difference is that it uses `bison` instead of `boost::spirit` for grammar parsing
* [CAN BUS tools in Python 3 (cantools)](https://github.com/eerimoq/cantools)