MessagePack for C++

According to MessagePack specification

m5gpack is a family of C++ types and functions to provide next functionality:

• serialize C++ data structures to MessagePack sequence of bytes
• deserialize series of bytes to C++ data tuples

A list of types:

namespace m5g {
   using value = ...;  /// The MessagePack value can contain 
                       /// nil, boolean, integer, float-point, 
                       /// blob, array, map and timestamp
   using nil_t = ...;
   constexpr auto nil = nil_t{};
   using bin   = ...;  /// Growable array of bytes (std::vector<uint8_t>)
   using array = ...;  /// Growable array of m5g::value`s (std::vector<m5g::value>)
   using arr   = array;
   using map   = ...;  /// Growable assosiative array of m5g::value`s
   using ext   = ...;  /// see MessagePack specification
   using timestamp = ...;   /// Timestamp representation seconds+nanoseconds
   using stream = ...; /// Stream of bytes. To be stored or transferred.
                       /// m5g::value could be serialized to 
                       /// and deserialized from m5g::stream 
                       /// using operators << and >>
   using byte_stream = stream;
}

m5g::value is extended std::variant<nil_t,bin,arr,map,ext,timestamp>. m5g::value is constructable from any of MessagePack types. Everything applicable to std::variant<> is also applicable to m5g::value, i.e std::visit(). m5g::value could be serialized to m5g::stream and deserialized from it. m5g::stream in its turn is an extension of std::vector<uint8_t>, all functions applicable to std::vector<uint8_t> are also applicable to m5g::stream.

Example of operation

Lets consider example program m5gpack-demo.cpp

ToDo add demo program source

This is an output from ./m5gpack-demo

ToDo add output

Build and run it with:

cmake -Bbuild  &&  cmake --build build  &&  ./build/m5gpack-demo 

Integrate to user project [TODO validate and fix]

1. The most straightforward way is to include this project's directory.

I suggest to use git subrepo instead of git subtree and git submodule.

git subrepo clone [email protected]:kyb/m5gpack.git m5gpack

Then add m5gpack project directory to includes.

2. Using the only header file – may be the most convenient way

Download amalgama header from the project's releases page

cd your/project/include_dir
curl -fsSL https://gitlab.com/kyb/m5gpack/raw/artifacts/master/$(curl https://gitlab.com/kyb/m5gpack/raw/artifacts/master/m5gpack.hh -fsSL) -o m5gpack.hh

3. Using CMake target_link_libraries with interface library

Assuming the repo has been already cloned as sugested in (1)
Since m5gpack this is header-only library there is no need to link with it. But CMake has feature INTERFACE LIBRARIES. m5gpack provides two interface libraries: m5gpack and m5gpack_amalgama. Linking against them addes include directory to the target.

1. m5gpack

   target_link_libraries(your_executable PRIVATE m5gpack)
   

   #include "m5gpack.hpp"
   #include "byte_range.hpp"
   #include "byte_range_ascii.hpp"
   #include "byte_range_hex.hpp"
   

2. m5gpack_amalgama

   target_link_libraries(your_executable PRIVATE m5gpack_amalgama)
   

   #include "m5gpack.hh"