PackedLinkImpl.h

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
/*
 * Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration.
 */
 
 
#ifndef ATHCONTAINERS_PACKEDLINKIMPL_H
#define ATHCONTAINERS_PACKEDLINKIMPL_H
 
 
#ifndef XAOD_STANDALONE
#include "AthLinks/tools/ElementLinkTraits.h"
#endif
#include "CxxUtils/ones.h"
#include <concepts>
#include <cstdint>
#include <cassert>
 
 
namespace SG {
 

struct PackedLinkBase
{
  static constexpr unsigned NBITS = 32;
  static constexpr unsigned COLLECTION_NBITS = 8;
  static constexpr unsigned INDEX_NBITS = NBITS - COLLECTION_NBITS;
  static constexpr uint32_t COLLECTION_MAX = CxxUtils::ones<uint32_t> (COLLECTION_NBITS);
  static constexpr uint32_t INDEX_MAX = CxxUtils::ones<uint32_t> (INDEX_NBITS);

  PackedLinkBase();
 

  PackedLinkBase (unsigned int collection, unsigned int index);
 

  bool operator== (const PackedLinkBase& other) const;
 

  unsigned int collection() const;
 

  unsigned int index() const;
 

  void setCollection (unsigned int collection);
 

  void setIndex (unsigned int index);
 
 
private:
  uint32_t m_packed;
};
 

template <class STORABLE>
#ifndef XAOD_STANDALONE
// To be usable as a packed link, the index must be integral.
requires (std::integral<typename SG::ElementLinkTraits<STORABLE>::IndexingPolicy::index_type>)
#endif
struct PackedLink
  : public PackedLinkBase
{
public:
  using PackedLinkBase::PackedLinkBase;
};
 
 
} // namespace SG
 
 
#include "AthContainers/PackedLinkImpl.icc"
 
 
#endif // not ATHCONTAINERS_PACKEDLINKIMPL_H