How to convert csv file to json using C++

Question

Is there any existing standard frame works to do this? currently i'm converting csv fields to an array then converting to one more array as JSON format, which is very slow. I want to know if there are any standard frameworks available or any other fast method out there?

Answer 1

The library jscons allows you to do so without an additional array for the CSV data:

#include <iostream>
#include "jsoncons/json.hpp"
#include "jsoncons_ext/csv/csv.hpp"

using namespace std;
using namespace jsoncons;
using namespace jsoncons::csv;

int main(int argc, char** argv) {

    json result = decode_csv<json>(cin);

    cout << result << endl;

    return 0;
}

On Linux you could use it like this (assume convert is your compiled binary):

$ cat data.csv | convert

On Windows it might be:

> convert < data.csv

When you want to use this with file names you could do it like this:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <stdexcept>

#include "jsoncons/json.hpp"
#include "jsoncons_ext/csv/csv.hpp"

using namespace std;
using namespace jsoncons;
using namespace jsoncons::csv;

int main(int argc, char** argv) {
    try {
        vector<string> arguments(argv + 1, argv + argc);

        if (arguments.size() != 2)
            throw runtime_error("usage: convert <input> <output>");

        ifstream input(arguments[0]);
        ofstream output(arguments[1]);

        if (!input.is_open())
            throw runtime_error(arguments[0] + ": open failed");

        if (!output.is_open())
            throw runtime_error(arguments[1] + ": open failed");

        json result = decode_csv<json>(input);

        output << result << endl;
    }
    catch (exception& e) {
        cout << e.what() << endl;
    }

    return 0;
}

You should call it like this:

$ convert data.csv data.json

To compile all that you have to put the folders jsoncons and jsoncons_ext into your include directory.