In "Using the acl library to serialize and deserialize programming for C++ objects" , the function of serializing and deserializing C/C++ struct objects in the acl library is introduced, and a simple example is given. This article will introduce some more complex examples.
1. Example 1: Example of Supporting Multiple Inheritance
First define the struct.stub file:
#pragma once
#include <string>
struct student
{
std::string shcool;
std::string class_name;
};
struct province
{
std::string province_name;
std::string position;
};
struct user : student, province
{
std::string name;
int age;
bool male;
};
In the above definition, user inherits from student and province.
Then use the gson tool (run: ./gson -d ) to generate the target source and header files from this struct.stub: gson.cpp, gson.h, struct.h.
The business logic code can be written as follows:
#include "stdafx.h"
#include <list>
#include <vector>
#include <map>
#include <stdio.h>
#include <iostream>
#include <time.h>
#include "struct.h" // Converted from struct.stub by gson tool
#include "gson.h" // Generated by gson tool based on struct.stub
// serialization process
static void serialize(void)
{
user u;
u.name = "zsx";
u.age = 11;
u.male = true;
u.province_name = "省";
u.position = "位置";
u.shcool = "大学";
u.class_name = "班级";
acl::json json;
// Convert user object to json object
acl::json_node& node = acl::gson(json, u);
printf("serialize:\r\n");
printf("json: %s\r\n", node.to_string().c_str());
printf("\r\n");
}
// deserialization process
static void deserialize(void)
{
const char *s = "{\"shcool\": \"大学\", \"class_name\": \"班级\", \"province_name\": \"省\", \"position\": \"位置\", \"name\": \"zsx\", \"age\": 11, \"male\": true}";
printf("deserialize:\r\n");
acl::json json;
json.update(s);
user u;
// Convert json object to user object
std::pair<bool, std::string> ret = acl::gson(json.get_root(), u);
// If the conversion fails, print the reason for the conversion failure
if (ret.first == false)
printf("error: %s\r\n", ret.second.c_str());
else
{
printf("name: %s, age: %d, male: %s\r\n",
u.name.c_str(), u.age, u.male ? "yes" : "no");
printf("province_name: %s, position: %s\r\n",
u.province_name.c_str(), u.position.c_str());
printf("shcool: %s, class_name: %s\r\n",
u.shcool.c_str(), u.class_name.c_str());
}
}
int main(void)
{
serialize();
deserialize();
return 0;
}
Compile and run the example, the results are as follows:
serialize:
json: {"shcool": "大学", "class_name": "班级", "province_name": "省", "position": "位置", "name": "zsx", "age": 11, "male": true}
deserialize:
name: zsx, age: 11, male: yes
province_name: province, position: position
shcool: university, class_name: class
2. Example 2: An example of supporting C++11
Define the struct.stub file as follows:
#pragma once
struct user
{
// constructor with parameters
user(const char* user_name, const char* user_domain,
int user_age, bool user_male)
: username(user_name)
, domain(user_domain)
, age(user_age)
, male(user_male)
{}
user() {}
~user() {}
acl::string username;
acl::string domain;
int age = 100;
bool male = true;
};
struct message
{
int type;
acl::string cmd;
std::list<user> user_list;
std::list<user> user_vector;
std::map<acl::string, user> user_map;
std::list<user*> *user_list_ptr = nullptr;
std::vector<user*> *user_vector_ptr = nullptr;
std::map<acl::string, user*> *user_map_ptr = nullptr;
int n = 100; // c++11 allows initialization of member variables
long n1 = 1000;
long long int n2 = 1000;
short n3 = 100;
// Gson @ optional
user* u = nullptr;
message() {}
~message()
{
if (user_list_ptr)
{
for (auto it : *user_list_ptr)
delete it;
delete user_list_ptr;
}
if (user_vector_ptr)
{
for (auto it : *user_vector_ptr)
delete it;
delete user_vector_ptr;
}
if (user_map_ptr)
{
for (auto it : *user_map_ptr)
delete it.second;
delete user_map_ptr;
}
}
};
Use the gson tool to generate the same three files from the above stub file: gson.cpp, gson.h, struct.h, and then write the business processing code as follows:
#include "stdafx.h"
#include <list>
#include <vector>
#include <map>
#include <stdio.h>
#include <iostream>
#include <time.h>
#include "struct.h"
#include "gson.h"
static void print_msg(message& msg)
{
printf("=======================================================\r\n");
printf("type: %d\r\n", msg.type);
printf("cmd: %s\r\n", msg.cmd.c_str());
printf("-------------------- user list ------------------------\r\n");
size_t i = 0;
for (auto cit : msg.user_list)
{
printf(">>username: %s, domain: %s, age: %d, male: %s\r\n",
cit.username.c_str(), cit.domain.c_str(),
cit.age, cit.male ? "true" : "false");
if (++i >= 10)
break;
}
printf("-------------------- user vector ----------------------\r\n");
i = 0;
for (auto cit : msg.user_vector)
{
printf(">>username: %s, domain: %s, age: %d, male: %s\r\n",
cit.username.c_str(), cit.domain.c_str(),
cit.age, cit.male ? "true" : "false");
if (++i >= 10)
break;
}
printf("------------------- user map --------------------------\r\n");
i = 0;
for (auto cit : msg.user_map)
{
printf(">>key: %s, username: %s, domain: %s, age: %d, male: %s\r\n",
cit.first.c_str(),
cit.second.username.c_str(),
cit.second.domain.c_str(),
cit.second.age,
cit.second.male ? "true" : "false");
if (++i >= 10)
break;
}
printf("-------------------- user list ptr --------------------\r\n");
i = 0;
for (auto cit : *msg.user_list_ptr)
{
printf(">>username: %s, domain: %s, age: %d, male: %s\r\n",
cit->username.c_str(), cit->domain.c_str(),
cit->age, cit->male ? "true" : "false");
if (++i >= 10)
break;
}
printf("-------------------- user vector ptr ------------------\r\n");
i = 0;
for (auto cit : *msg.user_vector_ptr)
{
printf(">>username: %s, domain: %s, age: %d, male: %s\r\n",
cit->username.c_str(), cit->domain.c_str(),
cit->age, cit->male ? "true" : "false");
if (++i >= 10)
break;
}
printf("------------------- user map ptr ----------------------\r\n");
i = 0;
for (auto cit : *msg.user_map_ptr)
{
printf(">>key: %s, username: %s, domain: %s, age: %d, male: %s\r\n",
cit.first.c_str(),
cit.second->username.c_str(),
cit.second->domain.c_str(),
cit.second->age,
cit.second->male ? "true" : "false");
if (++i >= 10)
break;
}
printf("-------------------------------------------------------\r\n");
}
static void test(void)
{
//////////////////////////////////////////////////////////////////
// serialization process
message msg;
msg.user_list_ptr = new std::list<user*>;
msg.user_vector_ptr = new std::vector<user*>;
msg.user_map_ptr = new std::map<acl::string, user*>;
msg.type = 1;
msg.cmd = "add";
user u = {"zsx1", "263.net", 11, true};
msg.user_list.push_back(u);
msg.user_list.emplace_back(u);
msg.user_list.emplace_back("zsx1", "263.net", 13, false);
u = {"zsx2", "263.net", 11, true};
msg.user_vector.push_back(u);
msg.user_vector.emplace_back(u);
msg.user_vector.emplace_back("zsx2", "263.net4", 14, true);
u = {"zsx31", "263.net", 11, true};
msg.user_map[u.username] = u;
msg.user_map["zsx32"] = {"zsx32", "263.net", 11, true };
msg.user_list_ptr->push_back(new user("zsx4", "263.net1", 11, true));
msg.user_list_ptr->push_back(new user("zsx4", "263.net2", 12, true));
msg.user_vector_ptr->push_back(new user("zsx5", "263.net1", 11, true));
msg.user_vector_ptr->push_back(new user("zsx5", "263.net2", 12, true));
(*msg.user_map_ptr)["zsx61"] = new user("zsx61:", "263.net1", 11, true);
(*msg.user_map_ptr)["zsx62"] = new user("zsx62", "263.net2", 12, true);
acl::json json;
// Serialization
acl::json_node& node = acl::gson(json, msg);
printf("serialize: %s\r\n", node.to_string().c_str());
/////////////////////////////////////////////////////////////////////
// deserialization process
message msg1;
acl::json json1;
json1.update(node.to_string());
printf("json1 to_string: %s\r\n", json1.to_string().c_str());
// deserialize
std::pair<bool, std::string> ret = acl::gson(json1.get_root(), msg1);
if (ret.first == false)
printf("error: %s\r\n", ret.second.c_str());
else
print_msg(msg);
}
int main(void)
{
test();
return 0;
}
The above example mainly embodies two characteristics of gson: 1. It allows constructors, 2. It supports the initialization of structure members in C++11.
3. Reference
Article reference: " Using the acl library for serialization and deserialization of C++ objects "
More examples: https://github.com/acl-dev/acl/tree/master/app/gson/test
acl github：https://github.com/acl-dev/acl
acl download: https://sourceforge.net/projects/acl/
QQ group: 242722074