PreparedItemCopy.h

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 /*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.
 
    This file is part of the TerraLib - a Framework for building GIS enabled applications.
 
    TerraLib is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License,
    or (at your option) any later version.
 
    TerraLib is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */
 
/*!
  \file terralib/memory/PreparedItemCopy.h
 
  \brief This class is used to optimize the copy of several dataSetItems by caching the mapping between the columns from the input and the output
*/
 
#ifndef __TERRALIB_MEMORY_INTERNAL_PREPAREDITEMCOPY_H
#define __TERRALIB_MEMORY_INTERNAL_PREPAREDITEMCOPY_H
 
// TerraLib
#include "Config.h"
 
#include <utility>
#include <vector>
 
namespace te
{
  namespace da
  {
// Forward declaration
    class DataSetItem;
  }
 
  namespace mem
  {
    using ColumnMapping = std::vector< std::pair<std::size_t, std::size_t> >;
 
    class DataSetItem;
 
    /*!
      \class PreparedItemCopy
 
      \brief This class is used to optimize the copy of several dataSetItems by caching the mapping between the columns from the input and the output
    */
    class TEMEMORYEXPORT PreparedItemCopy
    {
      public:
 
        PreparedItemCopy();
 
        ~PreparedItemCopy();
 
        void reset();
 
        /*!
        \brief Copies the values from the source dataSet item to the destination dataSet item by matching the column names. If a column from the source does not exist in the destination, it will not be copied
        */
        void copyValues(const te::da::DataSetItem* source, te::mem::DataSetItem* destination, bool copyGeometries = true) const;
 
    protected:
      
      /*!
        \brief Creates a list mapping the input columns to the output columns. This is used to optmize significantly when you need to copy several items with the same column order
        */
      ColumnMapping prepareCopyValues(const te::da::DataSetItem* source, te::mem::DataSetItem* destination, bool copyGeometries) const;
 
      /*!
        \brief Copies the values from the source dataSet item to the destination dataSet item using the given pre calculated vecColumnsMapping.
        */
      void copyValues(const te::da::DataSetItem* source, te::mem::DataSetItem* destination, const ColumnMapping& vecColumnsMapping) const;
 
    protected:
 
      mutable ColumnMapping m_columnMapping;
    };
  } // end namespace mem
}   // end namespace te
 
#endif  // __TERRALIB_MEMORY_INTERNAL_PREPAREDITEMCOPY_H