Added map based packing and converting example.

example/cpp03/map_based_versionup.cpp

@@ -0,0 +1,120 @@
+// MessagePack for C++ example
+//
+// Copyright (C) 2015 KONDO Takatoshi
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+
+#include <string>
+#include <iostream>
+#include <iomanip>
+#include <sstream>
+#include <cassert>
+
+#define MSGPACK_USE_BOOST
+#include <msgpack.hpp>
+
+struct base1 {
+    base1():a("default") {}
+    std::string a;
+    MSGPACK_DEFINE_MAP(a);
+};
+
+struct v1 : base1 {
+    v1():name("default"), age(0) {}
+    std::string name;
+    int age;
+    MSGPACK_DEFINE_MAP(MSGPACK_BASE_MAP(base1), name, age);
+};
+
+struct base2 {
+    base2():a("default") {}
+    std::string a;
+    MSGPACK_DEFINE_MAP(a);
+};
+
+// Removed: base1, name
+// Added  : base2, address
+struct v2 : base2 {
+    v2(): age(0), address("default") {}
+    int age;
+    std::string address;
+    MSGPACK_DEFINE_MAP(MSGPACK_BASE_MAP(base2), age, address);
+};
+
+// The member variable "age" is in common between v1 and v2.
+
+void print(std::string const& buf) {
+    for (std::string::const_iterator it = buf.begin(), end = buf.end();
+         it != end;
+         ++it) {
+        std::cout
+            << std::setw(2)
+            << std::hex
+            << std::setfill('0')
+            << (static_cast<int>(*it) & 0xff)
+            << ' ';
+    }
+    std::cout << std::dec << std::endl;
+}
+
+int main() {
+    { // pack v1, unpack, convert to v2
+        v1 v;
+        v.a = "ABC";
+        v.name = "John Smith";
+        v.age = 35;
+
+        std::stringstream ss;
+        msgpack::pack(ss, v);
+
+        print(ss.str());
+
+        msgpack::unpacked unp = msgpack::unpack(ss.str().data(), ss.str().size());
+
+        msgpack::object obj = unp.get();
+        std::cout << obj << std::endl;
+
+        v2 newv = obj.as<v2>();
+
+        std::cout << "v2::a       " << newv.a << std::endl;
+        std::cout << "v2::age     " << newv.age << std::endl;
+        std::cout << "v2::address " << newv.address << std::endl;
+
+        // "age" is set from v1
+        assert(newv.a == "default");
+        assert(newv.age == 35);
+        assert(newv.address == "default");
+    }
+    { // create v2 object with zone, convert to v1
+        v2 v;
+        v.a = "DEF";
+        v.age = 42;
+        v.address = "Tokyo";
+
+        msgpack::zone z;
+        msgpack::object obj(v, z);
+        std::cout << obj << std::endl;
+
+        v1 newv = obj.as<v1>();
+
+        std::cout << "v1::a       " << newv.a << std::endl;
+        std::cout << "v1::name    " << newv.name << std::endl;
+        std::cout << "v1::age     " << newv.age << std::endl;
+
+        // "age" is set from v2
+        assert(newv.a == "default");
+        assert(newv.name == "default");
+        assert(newv.age == 42);
+    }
+}