RDefineReader.hxx

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// Author: Enrico Guiraud CERN 09/2020
 
/*************************************************************************
 * Copyright (C) 1995-2020, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#ifndef ROOT_RDF_RDEFINEREADER
#define ROOT_RDF_RDEFINEREADER
 
#include "RColumnReaderBase.hxx"
#include "RDefineBase.hxx"
#include <Rtypes.h>  // Long64_t, R__CLING_PTRCHECK
 
#include <limits>
#include <type_traits>
 
namespace ROOT {
namespace Internal {
namespace RDF {
 
namespace RDFDetail = ROOT::Detail::RDF;
 
void CheckDefineType(RDFDetail::RDefineBase &define, const std::type_info &tid);
 
/// Column reader for defined (aka custom) columns.
class R__CLING_PTRCHECK(off) RDefineReader final : public ROOT::Detail::RDF::RColumnReaderBase {
   /// Non-owning reference to the node responsible for the custom column. Needed when querying custom values.
   RDFDetail::RDefineBase &fDefine;
 
   /// Non-owning ptr to the value of a custom column.
   void *fCustomValuePtr = nullptr;
 
   /// The slot this value belongs to.
   unsigned int fSlot = std::numeric_limits<unsigned int>::max();
 
   void *GetImpl(Long64_t entry) final
   {
      fDefine.Update(fSlot, entry);
      return fCustomValuePtr;
   }
 
public:
   RDefineReader(unsigned int slot, RDFDetail::RDefineBase &define, const std::type_info &tid)
      : fDefine(define), fCustomValuePtr(define.GetValuePtr(slot)), fSlot(slot)
   {
      CheckDefineType(define, tid);
   }
};
 
}
}
}
 
#endif