/*! \file variant.hpp
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\brief Support for std::variant
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\ingroup STLSupport */
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/*
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Copyright (c) 2014, 2017, Randolph Voorhies, Shane Grant, Juan Pedro
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Bolivar Puente. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef CEREAL_TYPES_STD_VARIANT_HPP_
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#define CEREAL_TYPES_STD_VARIANT_HPP_
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#include "../cereal.hpp"
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#include <variant>
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#include <cstdint>
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namespace cereal
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{
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namespace variant_detail
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{
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//! @internal
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template <class Archive>
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struct variant_save_visitor
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{
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variant_save_visitor(Archive & ar_) : ar(ar_) {}
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template<class T>
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void operator()(T const & value) const
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{
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ar( CEREAL_NVP_("data", value) );
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}
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Archive & ar;
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};
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//! @internal
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template<int N, class Variant, class Archive>
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typename std::enable_if<N == std::variant_size_v<Variant>, void>::type
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load_variant(Archive & /*ar*/, int /*target*/, Variant & /*variant*/)
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{
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throw ::cereal::Exception("Error traversing variant during load");
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}
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//! @internal
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template<int N, class Variant, class Archive>
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typename std::enable_if<N < std::variant_size_v<Variant>, void>::type
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load_variant(Archive & ar, int target, Variant & variant)
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{
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if(N == target)
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{
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variant.template emplace<N>();
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ar( CEREAL_NVP_("data", std::get<N>(variant)) );
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}
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else
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load_variant<N+1>(ar, target, variant);
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}
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} // namespace variant_detail
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//! Saving for std::variant
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template <class Archive, typename VariantType1, typename... VariantTypes> inline
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void CEREAL_SAVE_FUNCTION_NAME( Archive & ar, std::variant<VariantType1, VariantTypes...> const & variant )
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{
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std::int32_t index = static_cast<std::int32_t>(variant.index());
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ar( CEREAL_NVP_("index", index) );
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variant_detail::variant_save_visitor<Archive> visitor(ar);
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std::visit(visitor, variant);
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}
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//! Loading for std::variant
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template <class Archive, typename... VariantTypes> inline
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void CEREAL_LOAD_FUNCTION_NAME( Archive & ar, std::variant<VariantTypes...> & variant )
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{
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using variant_t = typename std::variant<VariantTypes...>;
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std::int32_t index;
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ar( CEREAL_NVP_("index", index) );
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if(index >= static_cast<std::int32_t>(std::variant_size_v<variant_t>))
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throw Exception("Invalid 'index' selector when deserializing std::variant");
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variant_detail::load_variant<0>(ar, index, variant);
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}
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//! Serializing a std::monostate
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template <class Archive>
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void CEREAL_SERIALIZE_FUNCTION_NAME( Archive &, std::monostate const & ) {}
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} // namespace cereal
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#endif // CEREAL_TYPES_STD_VARIANT_HPP_
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