dataVectorAsELV.h

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
 
/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
// $Id$
 
 
#ifndef ATHCONTAINERS_DATAVECTORASELV_H
#define ATHCONTAINERS_DATAVECTORASELV_H
 
 
#include "AthContainers/AuxVectorData.h"
#include "AthContainers/OwnershipPolicy.h"
#include "AthContainers/exceptions.h"
#include "AthContainers/tools/CurrentEventStore.h"
#include "AthContainersInterfaces/AuxStore_traits.h"
#include "AthLinks/ElementLink.h"
#include <vector>
 
 
namespace SG {
 
 
#ifdef XAOD_STANDALONE
using AthContainers::IProxyDict;
#endif // XAOD_STANDALONE
 

template <class DV>
void dataVectorViewAsELV (const std::true_type&,
                          const DV& v,
                          std::vector<ElementLink<DV> >& ret,
                          IProxyDict* store)
{
  const DV* last_d = nullptr;
  const SG::AuxVectorData* last_b = nullptr;
  for (const typename DV::base_value_type* elt : v) {
    const SG::AuxVectorData* cont_b = elt->container();
    if (cont_b != last_b) {
      last_b = cont_b;
      last_d = dynamic_cast<const DV*>(cont_b);
    }
    if (!last_d)
      throw SG::ExcDVToELV ("Element not in a container");
    ret.emplace_back (*last_d, elt->index(), store);
  }
}
 
 

template <class DV>
void dataVectorViewAsELV (const std::false_type&,
                          const DV&,
                          std::vector<ElementLink<DV> >&,
                          IProxyDict*)
{
  throw SG::ExcDVToELV ("Element in view container does not derive from AuxElement.");
}
 
 

template <class DV>
std::vector<ElementLink<DV> >
dataVectorAsELV (const DV& v, IProxyDict* store = 0)
{
  std::vector<ElementLink<DV> > ret;
  size_t sz = v.size();
  ret.reserve (sz);
 
  if (!store) store = SG::CurrentEventStore::store();
 
  if (v.ownPolicy() == SG::OWN_ELEMENTS) {
    // Could hoist the sgkey lookup.
    // But this will probably not be a common case, so don't do that
    // unless it's needed.
    for (size_t i = 0; i < sz; i++)
      ret.emplace_back (v, i, store);
  }
  else {
    dataVectorViewAsELV (typename AuxStore_traits<DV>::flag(), v, ret, store);
  }
  
  return ret;
}
 
 
} // namespace SG
 
 
#endif // not ATHCONTAINERS_DATAVECTORASELV_H