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Extractor.h
//
// Extractor.h
//
// $Id: //poco/1.4/Data/ODBC/include/Poco/Data/ODBC/Extractor.h#1 $
//
// Library: Data/ODBC
// Package: ODBC
// Module:  Extractor
//
// Definition of the Extractor class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef DataConnectors_ODBC_Extractor_INCLUDED
#define DataConnectors_ODBC_Extractor_INCLUDED


#include "Poco/Data/ODBC/ODBC.h"
#include "Poco/Data/AbstractExtractor.h"
#include "Poco/Data/ODBC/Preparation.h"
#include "Poco/Data/ODBC/ODBCColumn.h"
#include "Poco/Data/ODBC/Error.h"
#include "Poco/Data/ODBC/Utility.h"
#include "Poco/Exception.h"
#include <map>
#ifdef POCO_OS_FAMILY_WINDOWS
#include <windows.h>
#endif
#include <sqltypes.h>


namespace Poco {
namespace Data {
namespace ODBC {


00062 class ODBC_API Extractor: public Poco::Data::AbstractExtractor
      /// Extracts and converts data values from the result row returned by ODBC.
      /// If NULL is received, the incoming val value is not changed and false is returned
{
public:
      Extractor(const StatementHandle& rStmt, 
            Preparation& rPreparation);
            /// Creates the Extractor.

      ~Extractor();
            /// Destroys the Extractor.

      bool extract(std::size_t pos, Poco::Int8& val);
            /// Extracts an Int8.

      bool extract(std::size_t pos, Poco::UInt8& val);
            /// Extracts an UInt8.

      bool extract(std::size_t pos, Poco::Int16& val);
            /// Extracts an Int16.

      bool extract(std::size_t pos, Poco::UInt16& val);
            /// Extracts an UInt16.

      bool extract(std::size_t pos, Poco::Int32& val);
            /// Extracts an Int32.

      bool extract(std::size_t pos, Poco::UInt32& val);
            /// Extracts an UInt32.

      bool extract(std::size_t pos, Poco::Int64& val);
            /// Extracts an Int64.

      bool extract(std::size_t pos, Poco::UInt64& val);
            /// Extracts an UInt64.

      bool extract(std::size_t pos, bool& val);
            /// Extracts a boolean.

      bool extract(std::size_t pos, float& val);
            /// Extracts a float.

      bool extract(std::size_t pos, double& val);
            /// Extracts a double.

      bool extract(std::size_t pos, char& val);
            /// Extracts a single character.

      bool extract(std::size_t pos, std::string& val);
            /// Extracts a string.

      bool extract(std::size_t pos, Poco::Data::BLOB& val);
            /// Extracts a BLOB.
      
      bool extract(std::size_t pos, Poco::Any& val);
            /// Extracts an Any.

      void setDataExtraction(Preparation::DataExtraction ext);
            /// Set data extraction mode.

      Preparation::DataExtraction getDataExtraction() const;
            /// Returns data extraction mode.

private:
00126       static const int CHUNK_SIZE = 1024;
      /// Amount of data retrieved in one SQLGetData() request when doing manual extract.

00129       static const std::string FLD_SIZE_EXCEEDED_FMT;
      /// String format for the exception message when the field size is exceeded.

      void checkDataSize(std::size_t size);
            /// This check is only performed for bound data
            /// retrieval from variable length columns.
            /// The reason for this check is to ensure we can
            /// accept the value ODBC driver is supplying
            /// (i.e. the bound buffer is large enough to receive
            /// the returned value)

      template<typename T>
00141       bool extractBoundImpl(std::size_t pos, T& val)
      {
            poco_assert (typeid(T) == _rPreparation[pos].type());
            val = *AnyCast<T>(&_rPreparation[pos]); 
            return true;
      }

      template<typename T>
      bool extractManualImpl(std::size_t pos, T& val, SQLSMALLINT cType)
      {
            SQLRETURN rc = 0;
            SQLLEN len = 0;
            T value = (T) 0;
            
            rc = SQLGetData(_rStmt, 
                  (SQLUSMALLINT) pos + 1, 
                  cType,  //C data type
                  &value, //returned value
                  0,      //buffer length (ignored)
                  &len);  //length indicator

            //for fixed-length data, buffer must be large enough
            //otherwise, driver may write past the end
            poco_assert_dbg (len <= sizeof(T));

            if (Utility::isError(rc))
                  throw StatementException(_rStmt, "SQLGetData()");
            
            if (SQL_NULL_DATA == len) val = (T) 0;
            else val = value;

            return true;
      }

      const StatementHandle& _rStmt;
      Preparation& _rPreparation;
      Preparation::DataExtraction _dataExtraction;
};


///
/// inlines
///


00186 inline void Extractor::setDataExtraction(Preparation::DataExtraction ext)
{
      _rPreparation.setDataExtraction(_dataExtraction = ext);
}


00192 inline Preparation::DataExtraction Extractor::getDataExtraction() const
{
      return _dataExtraction;
}


} } } // namespace Poco::Data::ODBC


#endif // DataConnectors_ODBC_Extractor_INCLUDED

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