cereal
A C++11 library for serialization
boost_variant.hpp
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4 /*
5  Copyright (c) 2014, Randolph Voorhies, Shane Grant
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30 #ifndef CEREAL_TYPES_BOOST_VARIANT_HPP_
31 #define CEREAL_TYPES_BOOST_VARIANT_HPP_
32 
33 #include "cereal/cereal.hpp"
34 #include <boost/variant.hpp>
35 #include <boost/mpl/size.hpp>
36 
37 namespace cereal
38 {
39  namespace variant_detail
40  {
42  template <class Archive>
43  struct variant_save_visitor : boost::static_visitor<>
44  {
45  variant_save_visitor(Archive & ar_) : ar(ar_) {}
46 
47  template<class T>
48  void operator()(T const & value) const
49  {
50  ar( CEREAL_NVP_("data", value) );
51  }
52 
53  Archive & ar;
54  };
55 
57  template<int N, class Variant, class ... Args, class Archive>
58  typename std::enable_if<N == boost::mpl::size<typename Variant::types>::value, void>::type
59  load_variant(Archive & /*ar*/, int /*target*/, Variant & /*variant*/)
60  {
61  throw ::cereal::Exception("Error traversing variant during load");
62  }
63 
65  template<int N, class Variant, class H, class ... T, class Archive>
66  typename std::enable_if<N < boost::mpl::size<typename Variant::types>::value, void>::type
67  load_variant(Archive & ar, int target, Variant & variant)
68  {
69  if(N == target)
70  {
71  H value;
72  ar( CEREAL_NVP_("data", value) );
73  variant = value;
74  }
75  else
76  load_variant<N+1, Variant, T...>(ar, target, variant);
77  }
78 
79  } // namespace variant_detail
80 
82  template <class Archive, typename VariantType1, typename... VariantTypes> inline
83  void CEREAL_SAVE_FUNCTION_NAME( Archive & ar, boost::variant<VariantType1, VariantTypes...> const & variant )
84  {
85  int32_t which = variant.which();
86  ar( CEREAL_NVP_("which", which) );
87  variant_detail::variant_save_visitor<Archive> visitor(ar);
88  variant.apply_visitor(visitor);
89  }
90 
92  template <class Archive, typename VariantType1, typename... VariantTypes> inline
93  void CEREAL_LOAD_FUNCTION_NAME( Archive & ar, boost::variant<VariantType1, VariantTypes...> & variant )
94  {
95  typedef typename boost::variant<VariantType1, VariantTypes...>::types types;
96 
97  int32_t which;
98  ar( CEREAL_NVP_("which", which) );
99  if(which >= boost::mpl::size<types>::value)
100  throw Exception("Invalid 'which' selector when deserializing boost::variant");
101 
102  variant_detail::load_variant<0, boost::variant<VariantType1, VariantTypes...>, VariantType1, VariantTypes...>(ar, which, variant);
103  }
104 } // namespace cereal
105 
106 #endif // CEREAL_TYPES_BOOST_VARIANT_HPP_
#define CEREAL_NVP_(name, value)
Convenience for creating a templated NVP.
Definition: helpers.hpp:199
Definition: boost_variant.hpp:43
Definition: access.hpp:40
Main cereal functionality.
#define CEREAL_LOAD_FUNCTION_NAME
The deserialization (load) function name to search for.
Definition: macros.hpp:85
#define CEREAL_SAVE_FUNCTION_NAME
The serialization (save) function name to search for.
Definition: macros.hpp:92