Added new example.

example/x3/parse.cpp

@@ -0,0 +1,119 @@
+// MessagePack for C++ example
+//
+// Copyright (C) 2017 KONDO Takatoshi
+//
+//    Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//    http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <iostream>
+#include <sstream>
+#include <cassert>
+
+// MSGPACK_USE_X3_PARSE should be defined before including msgpack.hpp
+// It usually defined as a compiler option as -DMSGPACK_USE_X3_PARSE.
+
+#include <msgpack.hpp>
+
+struct json_like_visitor : msgpack::v2::null_visitor {
+    json_like_visitor(std::string& s):m_s(s) {}
+
+    bool visit_nil() {
+        m_s += "null";
+        return true;
+    }
+    bool visit_boolean(bool v) {
+        if (v) m_s += "true";
+        else m_s += "false";
+        return true;
+    }
+    bool visit_positive_integer(uint64_t v) {
+        std::stringstream ss;
+        ss << v;
+        m_s += ss.str();
+        return true;
+    }
+    bool visit_negative_integer(int64_t v) {
+        std::stringstream ss;
+        ss << v;
+        m_s += ss.str();
+        return true;
+    }
+    bool visit_float(double v) {
+        std::stringstream ss;
+        ss << v;
+        m_s += ss.str();
+        return true;
+    }
+    bool visit_str(const char* v, uint32_t size) {
+        m_s += '"' + std::string(v, size) + '"';
+        return true;
+    }
+    bool start_array(uint32_t /*num_elements*/) {
+        m_s += "[";
+        return true;
+    }
+    bool end_array_item() {
+        m_s += ",";
+        return true;
+    }
+    bool end_array() {
+        m_s.erase(m_s.size() - 1, 1); // remove the last ','
+        m_s += "]";
+        return true;
+    }
+    bool start_map(uint32_t /*num_kv_pairs*/) {
+        m_s += "{";
+        return true;
+    }
+    bool end_map_key() {
+        m_s += ":";
+        return true;
+    }
+    bool end_map_value() {
+        m_s += ",";
+        return true;
+    }
+    bool end_map() {
+        m_s.erase(m_s.size() - 1, 1); // remove the last ','
+        m_s += "}";
+        return true;
+    }
+    void parse_error(size_t /*parsed_offset*/, size_t /*error_offset*/) {
+    }
+    void insufficient_bytes(size_t /*parsed_offset*/, size_t /*error_offset*/) {
+    }
+    std::string& m_s;
+};
+
+int main() {
+    std::stringstream ss;
+    std::map<std::string, std::vector<int>> v1 {
+        { "ABC", { 1, 2, 3 } },
+        { "DEFG", { 4, 5 } }
+    };
+    std::vector<std::string> v2 {
+        "HIJ", "KLM", "NOP"
+    };
+    msgpack::pack(ss, v1);
+    msgpack::pack(ss, v2);
+
+    std::string const& buf = ss.str();
+    auto it = buf.begin();
+    auto end = buf.end();
+    {
+        std::string str;
+        bool ret = msgpack::parse(it, end, json_like_visitor(str));
+        // it is updated here.
+        assert(ret);
+        std::cout << str << std::endl;
+    }
+    {
+        std::string str;
+        bool ret = msgpack::parse(it, end, json_like_visitor(str));
+        // it is updated here.
+        assert(ret);
+        std::cout << str << std::endl;
+    }
+}