helpers.hpp

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/*
  Copyright (c) 2014, 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 the copyright holder 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 THE COPYRIGHT HOLDER OR CONTRIBUTORS 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>
#include <memory>
#include <unordered_map>
#include <stdexcept>
 
#include "cereal/macros.hpp"
#include "cereal/details/static_object.hpp"
 
namespace cereal
{
  // ######################################################################

  struct Exception : public std::runtime_error
  {
    explicit Exception( const std::string & what_ ) : std::runtime_error(what_) {}
    explicit Exception( const char * what_ ) : std::runtime_error(what_) {}
  };
 
  // ######################################################################

  using size_type = CEREAL_SIZE_TYPE;
 
  // forward decls
  class BinaryOutputArchive;
  class BinaryInputArchive;
 
  // ######################################################################
  namespace detail
  {
    struct NameValuePairCore {}; 
    struct DeferredDataCore {}; 
  }
 
  // ######################################################################

  template <class T>
  class NameValuePair : detail::NameValuePairCore
  {
    private:
      // If we get passed an array, keep the type as is, otherwise store
      // a reference if we were passed an l value reference, else copy the value
      using Type = typename std::conditional<std::is_array<typename std::remove_reference<T>::type>::value,
                                             typename std::remove_cv<T>::type,
                                             typename std::conditional<std::is_lvalue_reference<T>::value,
                                                                       T,
                                                                       typename std::decay<T>::type>::type>::type;
 
      // prevent nested nvps
      static_assert( !std::is_base_of<detail::NameValuePairCore, T>::value,
                     "Cannot pair a name to a NameValuePair" );
 
      NameValuePair & operator=( NameValuePair const & ) = delete;
 
    public:

      NameValuePair( char const * n, T && v ) : name(n), value(std::forward<T>(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<typename std::remove_reference<T>::type>::type>::value,
                                         const void *,
                                         void *>::type;
 
    BinaryData( T && d, uint64_t s ) : data(std::forward<T>(d)), size(s) {}
 
    PT data;       
    uint64_t size; 
  };
 
  // ######################################################################

  template <class T>
  class DeferredData : detail::DeferredDataCore
  {
    private:
      // If we get passed an array, keep the type as is, otherwise store
      // a reference if we were passed an l value reference, else copy the value
      using Type = typename std::conditional<std::is_array<typename std::remove_reference<T>::type>::value,
                                             typename std::remove_cv<T>::type,
                                             typename std::conditional<std::is_lvalue_reference<T>::value,
                                                                       T,
                                                                       typename std::decay<T>::type>::type>::type;
 
      // prevent nested nvps
      static_assert( !std::is_base_of<detail::DeferredDataCore, T>::value,
                     "Cannot defer DeferredData" );
 
      DeferredData & operator=( DeferredData const & ) = delete;
 
    public:

      DeferredData( T && v ) : value(std::forward<T>(v)) {}
 
      Type value;
  };
 
  // ######################################################################
  namespace detail
  {
    // base classes for type checking
    /* The rtti virtual function only exists to enable an archive to
       be used in a polymorphic fashion, if necessary.  See the
       archive adapters for an example of this */
    class OutputArchiveBase
    {
      public:
        OutputArchiveBase() = default;
        OutputArchiveBase( OutputArchiveBase && ) CEREAL_NOEXCEPT {}
        OutputArchiveBase & operator=( OutputArchiveBase && ) CEREAL_NOEXCEPT { return *this; }
        virtual ~OutputArchiveBase() CEREAL_NOEXCEPT = default;
 
      private:
        virtual void rtti() {}
    };
 
    class InputArchiveBase
    {
      public:
        InputArchiveBase() = default;
        InputArchiveBase( InputArchiveBase && ) CEREAL_NOEXCEPT {}
        InputArchiveBase & operator=( InputArchiveBase && ) CEREAL_NOEXCEPT { return *this; }
        virtual ~InputArchiveBase() CEREAL_NOEXCEPT = default;
 
      private:
        virtual void rtti() {}
    };
 
    // forward decls for polymorphic support
    template <class Archive, class T> struct polymorphic_serialization_support;
    struct adl_tag;
 
    // used during saving pointers
    static const uint32_t msb_32bit  = 0x80000000;
    static const int32_t msb2_32bit = 0x40000000;
  }
 
  // ######################################################################

  template <class T>
  class SizeTag
  {
    private:
      // Store a reference if passed an lvalue reference, otherwise
      // make a copy of the data
      using Type = typename std::conditional<std::is_lvalue_reference<T>::value,
                                             T,
                                             typename std::decay<T>::type>::type;
 
      SizeTag & operator=( SizeTag const & ) = delete;
 
    public:
      SizeTag( T && sz ) : size(std::forward<T>(sz)) {}
 
      Type size;
  };
 
  // ######################################################################

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


    MapItem( Key && key_, Value && value_ ) : key(std::forward<Key>(key_)), value(std::forward<Value>(value_)) {}
 
    MapItem & operator=( MapItem const & ) = delete;
 
    KeyType key;
    ValueType value;

    template <class Archive> inline
    void CEREAL_SERIALIZE_FUNCTION_NAME(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 detail
  {

    namespace{ struct version_binding_tag {}; }
 
    // ######################################################################

    template <class T, class BindingTag = version_binding_tag> struct Version
    {
      static const std::uint32_t version = 0;
      // we don't need to explicitly register these types since they
      // always get a version number of 0
    };

    struct Versions
    {
      std::unordered_map<std::size_t, std::uint32_t> mapping;
 
      std::uint32_t find( std::size_t hash, std::uint32_t version )
      {
        const auto result = mapping.emplace( hash, version );
        return result.first->second;
      }
    }; // struct Versions
  } // namespace detail
} // namespace cereal
 
#endif // CEREAL_DETAILS_HELPERS_HPP_