v1_0_cpp_adaptor

adaptors

When you want to pack to msgpack::object from a various type object, you need an adaptor. Converting to msgpack::object from a various type object and vice versa, it requires an adaptor too.

See conversion.

predefined adaptors

msgpack-c provides predefined adaptors for C++ primitive types and standard libraries.

C++ type	msgpack::object type
bool	bool
char*	str
std::deque	array
char	positive/negative integer
signed ints *1	positive/negative integer
unsigned ints *2	positive integer
std::list	array
std::map	array
std::pair	array
std::set	array
std::string	str
std::vector	array
std::vector<char>	bin

C++11 type	msgpack::object type
std::array	array
std::array<char>	bin
std::forward_list	array
std::tuple	array
std::array	array
std::unordered_map	array
std::unordered_set	array

*1 signed ints signed char, signed short, signed int, signed long, signed long long

*2 unsigned ints unsigned char, unsigned short, unsigned int, signed long, signed long long

msgpack::object type is defined as follows: https://github.com/msgpack/msgpack/blob/master/spec.md

These adaptors are defined in the following directory: https://github.com/msgpack/msgpack-c/tree/cpp-1.0.1/include/msgpack/adaptor

defining custom adaptors

classes

intrusive approach

When you want to adapt your class to msgpack, use MSGPACK_DEFINE macro.

#include <msgpack_fwd.hpp>

struct your_class {
    int a;
    std::string b;
    MSGPACK_DEFINE(a, b);
};

#include <msgpack.hpp>

// ...

The macro MSGPACK_DEFINE provides packing, converting to msgpack object with zone, and converting to your_class from msgpack::object functionalities. your_class is packed/converted as msgpack array.

https://github.com/msgpack/msgpack-c/blob/cpp-1.0.1/example/cpp03/class_intrusive.cpp

non-intrusive approach

https://github.com/msgpack/msgpack-c/blob/cpp-1.0.1/example/cpp03/class_non_intrusive.cpp

enums

When you want to adapt enum or enum class to msgpack, use MSGPACK_ADD_ENUM macro.

#include <msgpack_fwd.hpp>

enum your_enum {
    elem1,
    elem2
};

MSGPACK_ADD_ENUM(your_enum);

enum class your_enum_class {
    elem1,
    elem2
};

MSGPACK_ADD_ENUM(your_enum_class);

#include <msgpack.hpp>

// ...

You need to use MSGPACK_ADD_ENUM in the global namespace. And you need to use MSGPACK_ADD_ENUM before include msgpack.hpp. You might need to re-struct your source code.

The macro MSGPACK_DEFINE provides packing, converting to msgpack object with or without zone, and converting to your_enum from msgpack::object functionalities. your_enum is packed/converted as msgpack positive/negative integer.

See an example.