gistfile1.txt

#include <msgpack.hpp>
#include <iostream>

struct pack_int32 {
public:
	pack_int32(int64_t value = 0) : value(value) { }
	operator int64_t() const { return value; }
	int64_t get() const { return value; }

public:
	template <typename Packer>
	void msgpack_pack(Packer& pk) const
	{
		if(value > std::numeric_limits<int32_t>::max()) {
			pk.pack_fix_int64(value);
		} else {
			pk.pack_fix_int32(value);
		}
	}

	void msgpack_unpack(msgpack::object o)
	{
		o.convert(&value);
	}

private:
	int64_t value;
};


int main(void)
{
	// wrap in time
	{
		int64_t val = 0;
		msgpack::sbuffer out;
		msgpack::pack(&out, pack_int32(val));
		std::cout << out.size() << " bytes" << std::endl;  // 5 bytes
	}

	// wrap in time
	{
		int64_t val = 1LL << 32;
		msgpack::sbuffer out;
		msgpack::pack(&out, pack_int32(val));
		std::cout << out.size() << " bytes" << std::endl;  // 9 bytes
	}

	// implicit conversion
	{
		pack_int32 val = 1LL << 32;
		int64_t prim = val;
		pack_int32 val2 = prim;
		bool eq = prim == val2;
	}
}