Added boost variant serialization

include/cereal/binary_archive/boost_variant.hpp

@@ -0,0 +1,99 @@
+/*
+  Copyright (c) 2013, Randolph Voorhies, Shane Grant
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+      * Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+      * Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+      * Neither the name of cereal nor the
+        names of its contributors may be used to endorse or promote products
+        derived from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#ifndef CEREAL_BINARY_ARCHIVE_BOOST_VARIANT_HPP_
+#define CEREAL_BINARY_ARCHIVE_BOOST_VARIANT_HPP_
+
+#include <cereal/binary_archive/binary_archive.hpp>
+#include <boost/variant.hpp>
+#include <boost/mpl/size.hpp>
+
+namespace cereal
+{
+  namespace binary_detail
+  {
+    struct variant_save_visitor : boost::static_visitor<> 
+    {
+      variant_save_visitor(BinaryOutputArchive & ar) : ar(ar) {}
+
+      template<class T>
+        void operator()(T const & value) const
+        {
+          ar & CEREAL_NVP(value); 
+        }
+
+      BinaryOutputArchive & ar;
+    };
+    
+    template<int N, class Variant, class ... Args>
+    typename std::enable_if<N == boost::mpl::size<typename Variant::types>::value, void>::type
+    load_variant(BinaryInputArchive & ar, int target, Variant & variant)
+    {
+      throw ::cereal::Exception("Error traversing variant during load");
+    }
+
+    template<int N, class Variant, class H, class ... T>
+    typename std::enable_if<N < boost::mpl::size<typename Variant::types>::value, void>::type
+    load_variant(BinaryInputArchive & ar, int target, Variant & variant)
+    {
+      if(N == target)
+      {
+        H value;
+        ar & CEREAL_NVP(value);
+        variant = value;
+      }
+      else
+        load_variant<N+1, Variant, T...>(ar, target, variant);
+    }
+
+  } // namespace binary_detail
+
+  //! Saving for boost::variant to binary
+  template <typename... VariantTypes> inline
+  void save( BinaryOutputArchive & ar, boost::variant<VariantTypes...> const & variant )
+  {
+    int which = variant.which();
+    ar & CEREAL_NVP(which);
+    binary_detail::variant_save_visitor visitor(ar);
+    variant.apply_visitor(visitor);
+  }
+
+  //! Loading for boost::variant from binary
+  template <typename... VariantTypes> inline
+  void load( BinaryInputArchive & ar, boost::variant<VariantTypes...> & variant )
+  {
+    typedef typename boost::variant<VariantTypes...>::types types;
+
+    int which;
+    ar & cereal::make_nvp("which", which);
+    if(which >= boost::mpl::size<types>::value) 
+      throw Exception("Invalid 'which' selector when deserializing boost::variant");
+
+    binary_detail::load_variant<0, boost::variant<VariantTypes...>, VariantTypes...>(ar, which, variant);
+  }
+} // namespace cereal
+
+#endif // CEREAL_BINARY_ARCHIVE_BOOST_VARIANT_HPP_