msgbuf 0.0.9

Protobuf-like data (de)serialisation using D meta programming.

To use this package, run the following command in your project's root directory:

Manual usage
Put the following dependency into your project's dependences section:

ubuntu macos windows coverage

D Message Buffers

I was pondering the use of either protobuf or flatbuffers for a private project of mine, and there are some good D modules out there that enable the use of those serialisation libraries from within D programs.

However, I was trying to find out if it would be possible to do a (de)serialisation without the use of external schema files that needed to be precompiled (i.e. .proto or .fbs) and instead use plain D data types directly.

This library is the result of this experiment.

It only uses D's brilliant meta programming capabilities to (de)serialise data from/to binary format. No external schema files or precompilation is required.

Tested with the following compilers:

  • LDC2 1.26.0, 1.27.0, 1.28.0
  • DMD64 v2.097.0, v2.097.2-beta.1, v2.098

LDC2 takes a bit longer to compile than DMD, but produces much faster code.

What works, what doesn't?


  • most structure based types should be ok (as long as the members are public)
  • types with private members can define toMsgBuf()/fromMsgBuf() methods for custom (de)serialization
  • static arrays
  • dynamic arrays
  • associative arrays
  • all basic D types
  • enum (only integers at the moment)
  • nested structures
  • as long as new fields are appended to the end, old programs can read new message formats and vice versa
  • oneof (types in a oneof message must be unique)
  • CI/CD (built and tested on Ubuntu, macOS and Windows)

Doesn't work (yet)

  • "any" (this should be easy to simulate using a ubyte[] member for the data and maybe a type / url / uuid field)
  • adding/removing fields at arbitrary places (though adding new fields to the end is fine)
  • D classes, unions (probably won't do)

Possible future improvements

  • fixing stuff that doesn't work yet if sensible
  • adding @attributes to D message structures and fields to specify e.g. field/version numbers
  • adding a JSON encoding like e.g. proto3 does (see:

Some Microbenchmarks, take with a grain of salt.

Using Flat msgbuf (i.e. similar to Google Flatbuffers)

serialized size: 130072 (Flat)
performed 1000 rounds in 39 ms (3335179 bytes / ms)

Using Variable msgbuf (i.e. similar to Google Protobuf)

serialized size: 109919 (Var)
performed 1000 rounds in 76 ms (1446302 bytes / ms)

Google Protobuf

serialized size: 109921
performed 1000 rounds in 96 ms (1145010 bytes / ms)

Google Flatbuffers (note: these figures need to be verified!)

serialized size: 130096
performed 1000 ops in 107 ms (7650790 bytes / ms)

I have never worked with flatbuffers before, so I welcome all constructive criticism.


Please refer to the samples directory.


  • v0.0.9 Removed bidirectional control characters from unicode tests.
  • v0.0.8 Added endianess (defaulting to little endian).
  • Sinisa Susnjar
0.0.9 2023-May-23
0.0.8 2021-Oct-07
0.0.7 2021-Aug-24
0.0.6 2021-Aug-14
0.0.5 2021-Jul-16
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