YamlToJson.cpp

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// Original source code from https://github.com/mircodezorzi/tojson (MIT License)
 
#include "YamlToJson.hpp"
 
#include <polyfem/utils/Logger.hpp>
 
#include <yaml-cpp/yaml.h>
 
namespace polyfem::io
{
    namespace
    {
        inline nlohmann::json parse_scalar(const YAML::Node &node)
        {
            int i;
            double d;
            bool b;
            std::string s;
 
            // handle special bool values in YAML: y, yes, on, n, no, off
            if (YAML::convert<std::string>::decode(node, s) && s == "y")
                log_and_throw_error("ambiguous yaml value: {} could be bool or string", s);
 
            if (YAML::convert<int>::decode(node, i))
                return i;
            if (YAML::convert<double>::decode(node, d))
                return d;
            if (YAML::convert<bool>::decode(node, b))
                return b;
            if (YAML::convert<std::string>::decode(node, s))
                return s;
 
            return nullptr;
        }
 
        inline nlohmann::json yaml_to_json(const YAML::Node &root)
        {
            nlohmann::json j{};
 
            switch (root.Type())
            {
            case YAML::NodeType::Null:
                break;
            case YAML::NodeType::Scalar:
                return parse_scalar(root);
            case YAML::NodeType::Sequence:
                for (auto &&node : root)
                    j.emplace_back(yaml_to_json(node));
                break;
            case YAML::NodeType::Map:
                for (auto &&it : root)
                    j[it.first.as<std::string>()] = yaml_to_json(it.second);
                break;
            default:
                break;
            }
            return j;
        }
    } // namespace
 
    json yaml_string_to_json(const std::string &yaml_str)
    {
        YAML::Node root = YAML::Load(yaml_str);
        return yaml_to_json(root);
    }
 
    json yaml_file_to_json(const std::string &yaml_filepath)
    {
        YAML::Node root = YAML::LoadFile(yaml_filepath);
        return yaml_to_json(root);
    }
} // namespace polyfem::io