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/*!
 * @file datavariant.h
 * @brief defines a class that can hold every datatype (Header only)
 * @details
 * @author Bernhard Buchwinkler
 * @date august 2010
 */
#ifndef ORG_PROGGEN_DEDUPE_DATAVARIANT_H
#define ORG_PROGGEN_DEDUPE_DATAVARIANT_H

#include <typeinfo>
#include <string>
#include "statedataholding.h"

#include <iostream>

namespace Dedupe
{
  /**
    *Namespace Dataholding contains everything to operate the dataholding
    *module
    */
  namespace Dataholding
  {
    /**
      *Namespace Variant includes two classes to handle various datatypes
      *which come out of an SQLite Database (alternative to BOOST::Variant)
      */

    namespace Variant
    {
      /**
        *Data is a pure virtual baseclass to use baseclasspointers for the
        *following class
        */

      class Data
      {
        public:
        virtual const std::type_info & GetType() const = 0;
      };

      /**
        *DataVariant is a template, that can hold every datatype
        */

      template<class T> class DataVariant : public Data
      {
        T HoldedData;

        public:

        /**
          *To construct such a object, the datatype in the template and
          *the given data must be the same datatype
          */
        DataVariant( T data ) : HoldedData( data ) {};

        /**
          *@return the holded filetype as type_info struct
          */

        virtual const std::type_info & GetType() const
        {
          const std::type_info &ti = typeid( HoldedData );

          return ti;
        }

        /**
          *@return the holded data
          */
        T GetData() const
        {
          return HoldedData;
        }
      };


      /**
        *A free function to get the data from GetData while using only the
        *baseclasspointer. First argument is the baseclasspointer, second
        *argument is the variable where the data is written, if there were no
        *cast errors.
        *@return one type from CastResults
        */
      template<class T> CastResults CastDataVariant( Data *incoming, T &returning )
      {
        /*Make sure, holded data and the
          returning variable are frome the same type
        */
        if( incoming->GetType() != typeid( T ) ) return DifferentDatatypes;

        //Define the pointer here, cause the cast is in a different scope
        DataVariant<T> *ptr = NULL;

        //catch bad_cast exceptions and return an BadCastExecption error
        try
        {
          ptr = dynamic_cast
          <Dedupe::Dataholding::Variant::DataVariant<T> *>(incoming);
        }
        catch (std::bad_cast& bc)
        {
          return BadCastException;
        }

        if( ptr == NULL ) return CouldNotCast;
        //write the data to the returning varible
        returning = ptr->GetData();

        return CastOK;
      }
    }
  }
}
#endif

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Dedupe::Dataholding::Variant::Data *Basepointer = new Dedupe::Dataholding::Variant::Datavariant<int>(20);

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 if( incoming->GetType() != typeid( T ) ) return DifferentDatatypes;

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xin@trinity:~/workspace/dedupe/branches/dataholding$ cmake .
-- Configuring done
CMake Error in CMakeLists.txt:
  Cannot find source file "testsqlitewrapper.h".  Tried extensions .c .C .c++
  .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp .hxx .in .txx


-- Build files have been written to: /home/xin/workspace/dedupe/branches/dataholding
xin@trinity:~/workspace/dedupe/branches/dataholding$ 

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basepointer = &IntegerObject;