json.hpp

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// Copyright (c) 2013-2023 Anton Kozhevnikov, Thomas Schulthess
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/** \file json.hpp
 *
 *  \brief Interface to nlohmann::json library and helper functions.
 */
 
#ifndef __JSON_HPP__
#define __JSON_HPP__
 
#include <fstream>
#define JSON_USE_IMPLICIT_CONVERSIONS 0
#include "nlohmann_json.hpp"
#include "core/rte/rte.hpp"
 
/// Read json dictionary from file or string.
/** Terminate if file doesn't exist. */
inline nlohmann::json try_parse(std::istream &is) {
    nlohmann::json dict;
 
    try {
        is >> dict;
    } catch (std::exception& e) {
        std::stringstream s;
        s << "cannot parse input JSON" << std::endl << e.what();
        RTE_THROW(s);
    }
 
    return dict;
}
 
inline nlohmann::json read_json_from_file(std::string const &filename) {
    std::ifstream file{filename};
    if (!file.is_open()) {
        std::stringstream s;
        s << "file " << filename << " can't be opened";
        RTE_THROW(s);
    }
 
    return try_parse(file);
}
 
inline nlohmann::json read_json_from_string(std::string const &str) {
    if (str.empty()) {
        return {};
    }
    std::istringstream input{str};
    return try_parse(input);
}
 
inline nlohmann::json read_json_from_file_or_string(std::string const& str__)
{
    if (str__.empty()) {
        return {};
    }
    // Detect JSON
    if (str__.find("{") == std::string::npos) {
        return read_json_from_file(str__);
    } else {
        return read_json_from_string(str__);
    }
}
 
#endif /* __JSON_HPP__ */