cereal/details/traits.hpp

#ifndef CEREAL_DETAILS_TRAITS_HPP_
#define CEREAL_DETAILS_TRAITS_HPP_

#include <type_traits>
#include <memory>

namespace cereal
{
  namespace traits
  {
    template<typename> struct Void { typedef void type; };

    // ######################################################################
    // Member Serialize
    template<typename T, class A, typename Sfinae = void>
      struct has_member_serialize: std::false_type {};

    template<typename T, class A>
      struct has_member_serialize< T, A,
      typename Void<
        decltype( std::declval<T&>().serialize( std::declval<A&>() ) )
        >::type
        >: std::true_type {};

    // ######################################################################
    // Non Member Serialize
    template<typename T, typename A> char & serialize(A&, T&);
    template<typename T, typename A>
      bool constexpr has_non_member_serialize()
      { return std::is_void<decltype(serialize(std::declval<A&>(), std::declval<T&>()))>::value; };

    // ######################################################################
    // Member Load
    template<typename T, class A, typename Sfinae = void>
      struct has_member_load: std::false_type {};

    template<typename T, class A>
      struct has_member_load< T, A,
      typename Void<
        decltype( std::declval<T&>().load( std::declval<A&>() ) )
        >::type
        >: std::true_type {};

    // ######################################################################
    // Non Member Load
    template<typename T, typename A> char & load(A&, T&);
    template<typename T, typename A>
      bool constexpr has_non_member_load()
      { return std::is_void<decltype(load(std::declval<A&>(), std::declval<T&>()))>::value; };

    // ######################################################################
    // Member Save
    template<typename T, class A, typename Sfinae = void>
      struct has_member_save: std::false_type {};

    template<typename T, class A>
      struct has_member_save< T, A,
      typename Void<
        decltype( std::declval<T const &>().save( std::declval<A&>() ) )
        >::type
        >: std::true_type {};

    // ######################################################################
    // Non Member Save
    template<typename T, typename A> char & save(A&, T const &);
    template<typename T, typename A>
      bool constexpr has_non_member_save()
      { return std::is_void<decltype(save(std::declval<A&>(), std::declval<T&>()))>::value; };

    // ######################################################################
    template <class T, class InputArchive, class OutputArchive>
      constexpr bool has_member_split()
      { return has_member_load<T, InputArchive>() && has_member_save<T, OutputArchive>(); }

    // ######################################################################
    template <class T, class InputArchive, class OutputArchive>
      constexpr bool has_non_member_split()
      { return has_non_member_load<T, InputArchive>() && has_non_member_save<T, OutputArchive>(); }

    // ######################################################################
    template <class T, class OutputArchive>
      constexpr bool is_output_serializable()
      {
        return
          has_member_save<T, OutputArchive>() ^
          has_non_member_save<T, OutputArchive>() ^
          has_member_serialize<T, OutputArchive>() ^
          has_non_member_serialize<T, OutputArchive>();
      }

    // ######################################################################
    template <class T, class InputArchive>
      constexpr bool is_input_serializable()
      {
        return
          has_member_load<T, InputArchive>() ^
          has_non_member_load<T, InputArchive>() ^
          has_member_serialize<T, InputArchive>() ^
          has_non_member_serialize<T, InputArchive>();
      }

    // ######################################################################
    template <class T>
    constexpr size_t sizeofArray( size_t rank = std::rank<T>::value )
    {
      return rank == 0 ? 1 : std::extent<T>::value * sizeofArray<typename std::remove_extent<T>::type>( rank - 1 );
    }

    // ######################################################################
    //! A macro to use to restrict which types of archives your serialize function will work for.
    /*! This requires you to have a template class parameter named Archive and replaces the void return
        type for your serialize function.

        INTYPE refers to the input archive type you wish to restrict on.
        OUTTYPE refers to the output archive type you wish to restrict on.

        For example, if we want to limit a serialize to only work with binary serialization:

        @code{.cpp}
        template <class Archive>
        CEREAL_ARCHIVE_RESTRICT_SERIALIZE(BinaryInputArchive, BinaryOutputArchive)
        serialize( Archive & ar, MyCoolType & m )
        {
          ar & m;
        }
        @endcode
     */
    #define CEREAL_ARCHIVE_RESTRICT_SERIALIZE(INTYPE, OUTTYPE) \
    typename std::enable_if<std::is_same<Archive, INTYPE>::value || std::is_same<Archive, OUTTYPE>::value, void>::type
  }
}

#endif // CEREAL_DETAILS_TRAITS_HPP_