c++ - rapidjson: How can I split a Document object to a smaller Document object? -

i working on c++ project , use rapidjson json parsing. have json:

{   "a": "vala",   "b": {     "ba": "valba",     "bb": "valbb",     "bc": "valbc"   },   "c": "valc" } 

i parse whole json , document object containing values. want somehow process document object , extract b part. if parsing json:

{   "b": {     "ba": "valba",     "bb": "valbb",     "bc": "valbc"   } } 

i thought of parsing document object myself wondering if there easier/faster way of doing that. ideas?

"b" element can extracted , put new document way:

#include <iostream> #include <rapidjson/document.h> #include <rapidjson/stringbuffer.h> #include <rapidjson/writer.h>  using namespace rapidjson;  int main(void) {     const char* json = "{\"a\": \"vala\",\"b\": {\"ba\": \"valba\",\"bb\": \"valbb\",\"bc\": \"valbc\"},\"c\": \"valc\"}";      document d;     d.parse<0>(json);      value& data = d["b"];      document d2;     d2.setobject();     d2.addmember("b", data, d2.getallocator());      rapidjson::stringbuffer buffer;     rapidjson::writer<rapidjson::stringbuffer> writer(buffer);     d2.accept(writer);      std::cout << buffer.getstring() << std::endl;      return 0; } 

output:

{"b":{"ba":"valba","bb":"valbb","bc":"valbc"}}