helpers.hpp

/*
  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_DETAILS_HELPERS_HPP_
#define CEREAL_DETAILS_HELPERS_HPP_

#include <type_traits>
#include <cstdint>
#include <utility>

namespace cereal
{
  // forward decls
  class BinaryOutputArchive;
  class BinaryInputArchive;

  // ######################################################################
  namespace detail
  {
    struct NameValuePairCore {};
  }


  template <class T>
  class NameValuePair : detail::NameValuePairCore
  {
    private:
      // If we get passed an RValue, we'll just make a local copy if it here
      // otherwise, we store a reference
      using DT = typename std::decay<T>::type;
      using Type = typename std::conditional<std::is_rvalue_reference<T>::value,
                                             DT,
                                            typename std::add_lvalue_reference<DT>::type>::type;
      // prevent nested nvps
      static_assert( !std::is_base_of<detail::NameValuePairCore, T>::value,
                     "Cannot pair a name to a NameValuePair" );

    public:

      NameValuePair( char const * n, T && v ) : name(n), value(const_cast<Type>(v)) {}

      char const * name;
      Type value;
  };


  template<class Archive, class T> inline
  typename
  std::enable_if<std::is_same<Archive, ::cereal::BinaryInputArchive>::value ||
                 std::is_same<Archive, ::cereal::BinaryOutputArchive>::value,
  T && >::type
  make_nvp( const char *, T && value )
  {
    return std::forward<T>(value);
  }


  template<class Archive, class T> inline
  typename
  std::enable_if<!std::is_same<Archive, ::cereal::BinaryInputArchive>::value &&
                 !std::is_same<Archive, ::cereal::BinaryOutputArchive>::value,
  NameValuePair<T> >::type
  make_nvp( const char * name, T && value)
  {
    return {name, std::forward<T>(value)};
  }


#define _CEREAL_NVP(name, value) ::cereal::make_nvp<Archive>(name, value)

  // ######################################################################

  template <class T>
  struct BinaryData
  {
    using PT = typename std::conditional<std::is_const<typename std::remove_pointer<T>::type>::value,
                                         const void *,
                                         void *>::type;

    BinaryData( T && d, uint64_t s ) : data(d), size(s) {}

    PT data;   
    uint64_t size; 
  };

  // ######################################################################
  namespace detail
  {
    // base classes for type checking
    struct OutputArchiveBase {};
    struct InputArchiveBase {};

    // forward decls for polymorphic support
    template <class Archive, class T> struct polymorphic_serialization_support;
    struct adl_tag;

    // used during saving pointers
    static const int32_t msb_32bit = 0x80000000;
    static const int32_t msb2_32bit = 0x40000000;
  }

  // ######################################################################

  template <class T>
  class SizeTag
  {
    private:
      // If we get passed an RValue, we'll just make a local copy if it here
      // otherwise, we store a reference
      using DT = typename std::decay<T>::type;
      using Type = typename std::conditional<std::is_rvalue_reference<T>::value,
                                             DT,
                                             typename std::add_lvalue_reference<DT>::type>::type;

    public:
      SizeTag( T && sz ) : size(const_cast<Type>(sz)) {}

      Type size;
  };

  // ######################################################################

  template <class Key, class Value>
  struct MapItem
  {
    using DecayKey = typename std::decay<Key>::type;
    using KeyType = typename std::conditional<
      std::is_rvalue_reference<Key>::value,
      DecayKey,
      typename std::add_lvalue_reference<DecayKey>::type>::type;

    using DecayValue = typename std::decay<Value>::type;
    using ValueType = typename std::conditional<
      std::is_rvalue_reference<Value>::value,
      DecayValue,
      typename std::add_lvalue_reference<DecayValue>::type>::type;


    MapItem( Key && key, Value && value ) : key(const_cast<KeyType>(key)), value(const_cast<ValueType>(value)) {}

    KeyType key;
    ValueType value;

    template <class Archive> inline
    void serialize(Archive & archive)
    {
      archive( make_nvp<Archive>("key",   key),
               make_nvp<Archive>("value", value) );
    }
  };


  template <class KeyType, class ValueType> inline
  MapItem<KeyType, ValueType> make_map_item(KeyType && key, ValueType && value)
  {
    return {std::forward<KeyType>(key), std::forward<ValueType>(value)};
  }
} // namespace cereal

#endif // CEREAL_DETAILS_HELPERS_HPP_