x2struct

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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
xml bson libconfig
Generate Golang struct
IMPORTANT

Basic usage

#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

Mandatory

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;
}

Alias

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;
}

Inherit

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;
}

Bit field

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 conditional

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;
}

char array

modify config.h to enable XTOSTRUCT_SUPPORT_CHAR_ARRAY

check exist

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;
}

local class

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

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;
}

Format indent

last two parameters of tojson control format indent

thirdparty class

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;
}

xml bson libconfig

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

Generate Golang struct

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"`
}

IMPORTANT

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.

yuanyewa / x2struct Goto Github PK

x2struct's Introduction

x2struct

Basic usage

Mandatory

Alias

Inherit

Bit field

Load conditional

char array

check exist

local class

customize type

Format indent

thirdparty class

xml bson libconfig

Generate Golang struct

IMPORTANT

x2struct's People

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