(C) 2019 Jaguar Land Rover
The vspec2c tooling allows a vehicle signal specification to be translated from its source YAML file to native C code that has the entire specification encoded in it.
The specification is encoded as two header files, one hosting a struct array with all signal specification data, and one with a set of macros to access signals.
The two header files are included by the application, which is then linked with the vehicle signal specification built in this repo.
Please see the schematics below for details.
The example signal_spec.h file contains an array of vss_signal_t
structs, each element defining one signal.
NOTE: signal_spec.h containing global definitions, should only be included by
a single source file in a project. If it is included multiple times, the
linker will failed with multiple defintions of vss_signal and other symbols.
signak_macro.h can be included by all source file that needs a macro reference to
specific signals
There is also a sha256 signature for the specification as a whole, which can be used by an application to ensure that the correct vehicle signal specification is being used.
To build the library providing the vss_... functions used to inspect the signal specification, run:
make
The build process generates libvss.so and libvss.a, to be linked
by the appliction.
To install the built vss library and header files under /usr/local, run:
make install
You can specify an alternate destination directory through the
DESTDIR environment variable:
DESTDIR=/usr make install
The demo can be built by changing into the example directory and run make:
cd example
make
The vspec2.py is executed to read the spec file and generate the
signal_spec.h and signal_macro.h files. Please see the top-level
README.md file for this repo for details on spec files, id files,
and other aspects of the signal specifictaion toolkit.
The vss_dump demo, which prints out the entire vehicle signal spec on screen, can be run from the example directory via:
./vss_dump