Convert Settings from Libconfig++ to NLohmann's JSON

libconfig-json.cpp

#include <config/config.h>
#include <nlohmann/json.hpp>

namespace libconfig
{
void to_json(nlohmann::json &j, const Setting &setting)
{
	json *data;

	try {
		auto n = setting.getName();
		data = &j[n];
	} catch (const std::exception &) {
		data = &j;
	}

	switch (setting.getType()) {
	case Setting::TypeInt:
		*data = (int) setting;
		break;
	case Setting::TypeInt64:
		*data = (long long) setting;
		break;
	case Setting::TypeFloat:
		*data = (double) setting;
		break;
	case Setting::TypeString:
		*data = (const char *) setting;
		break;
	case Setting::TypeBoolean:
		*data = (bool) setting;
		break;

	case Setting::TypeGroup:
		*data = json::object();
		for (auto &sub : setting)
			data->update(sub);
		break;

	case Setting::TypeArray:
	case Setting::TypeList:
		*data = json::array();
		for (auto &sub : setting)
			data->push_back(sub);
		break;

	case Setting::TypeNone:
	default:
		throw std::invalid_argument("unknown setting type");
		break;
	}
}
} // namespace libconfig