- Does serialization/de-serialization require dynamic memory allocation? From what I've seen it looks like it doesn't.
- How are you handling endianness? floating point numbers?
- How complete/tested is the library? Are you aware of projects using it?
This library works well in an embedded context. I've personally used it on Cortex-M class micro controller firmware.
The serializer/deserializer does not require dynamic memory allocation. Whether or not dynamic allocation happens depends on how you use the library. If you avoid using data types that perform dynamic allocation (e.g. std::vector) and use (or write) Reader/Writer types that use static memory (e.g. nop::BufferReader/nop::BufferWriter) then you should be fine.
There are some nice tricks you can use to permit protocols that have convenient dynamic containers on the host and static versions on the embedded device:
https://github.com/google/libnop/blob/master/docs/getting-st... https://github.com/google/libnop/blob/master/docs/getting-st... https://github.com/google/libnop/blob/master/examples/shared...
Endianness is assumed to be little because the vast majority of hardware is little endian. There are utilities to convert here:
https://github.com/google/libnop/blob/master/include/nop/uti...
These are not currently used by the Reader and Writer types included with libnop for efficiency, but are available for you to use in your own Reader and Writer types if you really need it.
Floating point is a much stickier problem due to lack of standardization across hardware. The library does not address this automatically and just packs floating point types in machine order. However, the library provides tools to help address the issue. One approach that works well is to use a fixed point representation for the wire type -- a value wrapper type is convenient for automating this:
https://github.com/google/libnop/blob/master/docs/getting-st...
See the Fixed template in the example. This is especially handy if you have a micro controller without floating point support or you want to minimize the size of the payload at the cost of range and/or precision.
The library has a complete suite of tests and 97.9% line coverage according to GCOV, with particular attention to conditional and error paths.
We use the library for a few internal embedded prototypes. I have not tracked its usage outside of Google since its recent release.
Best, C
Do you have any evidence of this? I would be flabbergasted if a modern compiler couldn't optimize out a no-op endiannes conversion.
Moreover, endian conversion templates are unusually frustrating in the current C++ standard. I wish there were a better way, but one does not currently exist.