json_serializers.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2023 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program 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.
 *
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
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 */
 
#ifndef JSON_SERIALIZERS_H_
#define JSON_SERIALIZERS_H_
 
#include <nlohmann/json.hpp>
#include <wx/string.h>
#include <optional>
 
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{
// silly hack to silence warnings about std::char_traits<wxUniChar> not being supported by the standard
// nolhmann json internally has its own char_traits templated to support some exotic char traits
template <>
struct char_traits<wxUniChar> : std::char_traits<char>
{
    using char_type = wxUniChar;
    using int_type = uint32_t;      // this is wxwidget's internal data type
 
    // Redefine to_int_type function
    static int_type to_int_type( char_type c ) noexcept { return static_cast<int_type>( c ); }
 
    static char_type to_char_type( int_type i ) noexcept { return static_cast<char_type>( i ); }
 
    static constexpr int_type eof() noexcept { return static_cast<int_type>( EOF ); }
};
} // namespace detail
NLOHMANN_JSON_NAMESPACE_END
 
namespace nlohmann
{
template <>
struct adl_serializer<wxString>
{
    static void from_json( const json& j, wxString& s )
    {
        s = wxString::FromUTF8( j.get<std::string>().c_str() );
    }
 
    static void to_json( json& j, const wxString& s ) { j = s.ToUTF8(); }
};
 
template <typename T>
struct adl_serializer<std::optional<T>>
{
    static void from_json( const json& j, std::optional<T>& opt )
    {
        if( j.is_null() )
        {
            opt = std::nullopt;
        }
        else
        {
            opt = j.template get<T>();
        }
    }
 
    static void to_json( json& j, const std::optional<T>& opt )
    {
        if( opt.has_value() )
        {
            j = *opt;
        }
        else
        {
            j = nullptr;
        }
    }
};
} // namespace nlohmann
 
 
#endif // JSON_SERIALIZERS_H_