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- Used to convert between C++ objects and json/xml/json/libconfig
- json/xml is header file only, no need to compile librarys
- json is enabled by default, others need to modify config.h
- The following example uses json as an example. Others can refer to api of x2struct::X in x2struct.hpp
- Basic usage
- Mandatory
- Alias
- Inherit
- Bit field
- Load conditional
- char array
- check exist
- local class
- customize type
- thirdparty class
- Format indent
- Qt support
- xml bson libconfig
- Generate Golang struct
- IMPORTANT
#include <iostream>
#include "x2struct/x2struct.hpp" // include this header file
using namespace std;
struct User {
int64_t id;
string name;
string mail;
User(int64_t i=0, const string& n="", const string& m=""):id(i),name(n),mail(m){}
XTOSTRUCT(O(id, name, mail)); // add XTOSTRUCT at the end of struct/class
};
struct Group {
string name;
int64_t master;
vector<User> members;
XTOSTRUCT(O(name, master, members)); // add XTOSTRUCT at the end of struct/class
};
int main(int argc, char *argv[]) {
Group g;
g.name = "C++";
g.master = 2019;
g.members.resize(2);
g.members[0] = User(1, "Jack", "[email protected]");
g.members[1] = User(2, "Pony", "[email protected]");
string json = x2struct::X::tojson(g); // C++ object to json
cout<<json<<endl;
Group n;
x2struct::X::loadjson(json, n, false); // json to C++ object
cout<<n.name<<endl;
vector<int> vi;
x2struct::X::loadjson("[1,2,3]", vi, false); // load vector directory
cout<<vi.size()<<','<<vi[1]<<endl;
map<int, int> m;
x2struct::X::loadjson("{\"1\":10, \"2\":20}", m, false); // load map directory
cout<<m.size()<<','<<m[2]<<endl;
return 0;
}- include "x2struct.hpp"
- add XTOSTRUCT at the end of struct, put all the variables inside "O"
- use x2struct::X::tojson to convert C++ object to json
- use x2struct::X::loadjson to load json to C++ object
- for json to C++ object
- use M to include those mandatory variables
- if mandatory field miss in json, an exception will throw
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Test {
int64_t id;
string name;
XTOSTRUCT(M(id), O(name)); // "id" is mandatory and "name" is optional
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"name\":\"Pony\"}";
x2struct::X::loadjson(json, t, false); // will throw exception(id is mandatory and no "id" in json)
return 0;
}- used for scenes where the variable name and json key name are inconsistent
- use A to include alias variable. "A" take two parameters, 1st is variable, 2nd is tag-field
- tag format is "[type:]alias[,extension]", Tag-field can contain multiple tags, separated by spaces
- type is one of "json"/"xml"/"bson"/"config", no type field in tag means this tag is applied to all type
- for example, "tid" means use tid as alias for all type
- "tid json:xid" means json use "xid" as alias and other types use "tid"
- extension only support "m" now, means mandatory(A like O, optional)
- if no alias in json, loadjson will also try variable name
- tojson use alias
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Test {
int64_t uid;
string name;
XTOSTRUCT(A(uid, "id"), O(name)); // "uid" use alias "id"
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"id\":123, \"name\":\"Pony\"}";
x2struct::X::loadjson(json, t, false);
cout<<t.uid<<endl;
return 0;
}
- use I to include parents classs
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct P1 {
string mail;
XTOSTRUCT(O(mail));
};
struct P2 {
int64_t version;
XTOSTRUCT(O(version));
};
struct Test:public P1, public P2 {
int64_t uid;
string name;
XTOSTRUCT(I(P1, P2), O(uid, name));
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"mail\":\"[email protected]\", \"version\":2019, \"id\":123, \"name\":\"Pony\"}";
x2struct::X::loadjson(json, t, false);
cout<<t.mail<<endl;
cout<<t.version<<endl;
return 0;
}
- use B to include those bit field variables
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Test {
int16_t ver:8;
int16_t len:8;
string name;
XTOSTRUCT(B(ver, len), O(name));
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"ver\":4, \"len\":20, \"name\":\"IPv4\"}";
x2struct::X::loadjson(json, t, false);
cout<<t.ver<<endl;
cout<<t.len<<endl;
return 0;
}- load at most one object from an array of objects
- use C to include those conditional variables at the beginning of XTOSTRUCT
- conditional variables still need included in one of O,A or M
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Task {
int id;
string name;
XTOSTRUCT(O(id, name));
};
struct Test {
int tid;
Task task;
XTOSTRUCT(C(task), O(tid, task)); // task included in C and O, C must at beginning of XTOSTRUCT
/*
XTOSTRUCT_CONDITION take two parameters, 1st is class name, 2nd is variable name
XTOSTRUCT_CONDITION defined a function take one parameter named "obj", pointer to xdoc of variable
"task" in json is array, load conditional only load the one that this functin return true
*/
XTOSTRUCT_CONDITION(Test, task) {
int id;
// only load the one that Task.id is equal to Test.tid
return obj.convert("id", id)&&id==this->tid;
}
};
int main(int argc, char *argv[]) {
string s = "{\"tid\":2019,\"task\":[{\"id\":2018,\"name\":\"hello\"},{\"id\":2019,\"name\":\"world\"}]}";
Test t;
x2struct::X::loadjson(s, t, false);
cout<<t.task.name<<endl;
}modify config.h to enable XTOSTRUCT_SUPPORT_CHAR_ARRAY
- to check if field exist after load json to C++ object
- use xhas to check if field exist
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Test {
int64_t id;
string name;
XTOSTRUCT(O(id, name));
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"name\":\"Pony\"}";
x2struct::X::loadjson(json, t, false, true); // 4th parameter apply true
cout<<t.xhas("id")<<endl; // use xhas to check exist
cout<<t.xhas("name")<<endl;
return 0;
}- XTOSTRUCT will add some template function, and local class could not define template function
- use XTOSTRUCT_NT(types) instead of XTOSTRUCT, types support Json/Xml/Bson/Config
- need C++11 support
- not support load conditional now
// nt.cpp
// g++ -o t nt.cpp -std=c++11
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
int main(int argc, char *argv[]) {
struct Test {
int64_t id;
string name;
XTOSTRUCT_NT(Json)(O(id, name));
};
Test t;
string json="{\"id\":123, \"name\":\"Pony\"}";
x2struct::X::loadjson(json, t, false);
cout<<t.name<<endl;
return 0;
}- customize type is string
- need implement:
- std::string format() const; use to format data to string
- void parse(const std::string&); use to load string to data
- typedef XType to define customize type
- following is an IPv4 example
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
// just example, no error handle
struct _XIPv4 {
uint32_t ip;
std::string format() const {
char buf[64];
int len = sprintf(buf, "%u.%u.%u.%u", ip>>24, 0xff&(ip>>16), 0xff&(ip>>8), 0xff&ip);
return string(buf, len);
}
void parse(const std::string& d) {
uint32_t u[4];
sscanf(d.c_str(), "%u.%u.%u.%u", &u[0], &u[1], &u[2], &u[3]);
ip = (u[0]<<24)+(u[1]<<16)+(u[2]<<8)+u[3];
}
};
typedef x2struct::XType<_XIPv4> XIPv4;
struct Test {
XIPv4 ip;
XIPv4 mask;
XTOSTRUCT(O(ip, mask));
};
int main(int argc, char *argv[]) {
Test t;
string json="{\"ip\":\"192.168.1.2\", \"mask\":\"255.255.255.0\"}";
x2struct::X::loadjson(json, t, false);
cout<<t.ip.ip<<','<<t.mask.ip<<endl;
cout<<x2struct::X::tojson(t)<<endl;
return 0;
}- last two parameters of tojson control format indent
- modify config.h to enable macro XTOSTRUCT_QT
- support QString/QList/QMap/QVector now
- need c++11 support
- use XTOSTRUCT_OUT instead of XTOSTRUCT
#include <sys/time.h>
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
/*
struct timeval {
time_t tv_sec;
suseconds_t tv_usec;
};
*/
// timeval is thirdparty struct
XTOSTRUCT_OUT(timeval, O(tv_sec, tv_usec));
struct T {
int a;
string b;
timeval t;
XTOSTRUCT(O(a, b, t));
};
int main(int argc, char *argv[]) {
T t;
T r;
t.a = 123;
t.b = "x2struct";
t.t.tv_sec = 888;
t.t.tv_usec = 999;
string s = x2struct::X::tojson(t);
cout<<s<<endl;
x2struct::X::loadjson(s, r, false);
cout<<r.a<<','<<r.b<<','<<r.t.tv_sec<<','<<r.t.tv_usec<<endl;
return 0;
}- need to modify config.h to enable
- not support load vector map directory
- xml/libconfig not permit use digit as key, so if want to use map<int, xxx>, key need add 'x', e.g. x100
- mongoxclient(https://github.com/xyz347/mongoxclient) is a wrapper of mongo-cxx-driver use bson
- use to generate Golang struct define by C++ struct
- need to define macro XTOSTRUCT_GOCODE
// go.cpp
// g++ -o t go.cpp -DXTOSTRUCT_GOCODE
#include <iostream>
#include "x2struct/x2struct.hpp"
using namespace std;
struct Test {
int64_t id;
vector<string> names;
XTOSTRUCT(O(id, names));
};
int main(int argc, char *argv[]) {
Test t;
cout<<x2struct::X::togocode(t, true, true, true)<<endl; // last 3 parameter to generate (json/bson/xml) tags
return 0;
}
output is:
type Test struct {
Id int64 `json:"id" bson:"id" xml:"id"`
Names []string `json:"names" bson:"names" xml:"names"`
}- Encode/decode json is use rapidjson
- Decode xml is use rapidxml
- Decode bson is use libbson
- Decode libconfig is use libconfig
- Encode of xml/bson is written by myself. Without reference to the RFC, there may be cases where the standard is not met.
- The library of bson/libconfig is precompiled. The environment is: Ubuntu12.04 g++4.9.2. Other environments may need to download the code and recompile if you need to use these two libraries.