vpJsonParsing.h

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2023 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * JSON parsing helpers.
 */
 
#ifndef _vpJsonParsing_h_
#define _vpJsonParsing_h_
 
#include <visp3/core/vpConfig.h>
 
#ifdef VISP_HAVE_NLOHMANN_JSON
#include <nlohmann/json.hpp>
 
template<typename E>
int flagsFromJSON(const nlohmann::json &j)
{
  int flags = 0;
  if (j.is_array()) {
    flags = 0;
    for (const auto &v : j) {
      E value = v.get<E>(); // If a value is incorrect, this will default to the first value of the enum
      flags |= value;
    }
  }
  else if (j.is_number_integer()) {
    flags = j.get<int>();
  }
  return flags;
}
 
template<typename E>
nlohmann::json flagsToJSON(const int flags, const std::vector<E> &options)
{
  nlohmann::json j = nlohmann::json::array();
  for (const E option : options) {
    if (flags & option) {
      j.push_back(option);
    }
  }
  return j;
}
 
template<typename T>
bool convertFromTypeAndBuildFrom(const nlohmann::json &, T &)
{
  return false;
}
 
template<typename T, typename O, typename... Os>
bool convertFromTypeAndBuildFrom(const nlohmann::json &j, T &t)
{
  if (j["type"] == O::jsonTypeName) {
    O other = j;
    t.buildFrom(other);
    return true;
  }
  else {
    return convertFromTypeAndBuildFrom<T, Os...>(j, t);
  }
}
 
#endif
#endif