PackedLinkAccessor.icc

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/*
 * Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration.
 */
/**
 * @file AthContainers/PackedLinkAccessor.icc
 * @author scott snyder <snyder@bnl.gov>
 * @date Oct, 2023
 * @brief Helper class to provide type-safe access to aux data,
 *        specialized for @c PackedLink.
 */
 
 
#include "AthContainers/AuxElement.h"
#include "AthContainers/AuxTypeRegistry.h"
#include "AthContainers/exceptions.h"
#include "CxxUtils/checker_macros.h"
 
 
namespace SG {
 
 
/**
 * @brief Constructor.
 * @param name Name of this aux variable.
 *
 * The name -> auxid lookup is done here.
 */
template <class CONT, class ALLOC>
inline
Accessor<PackedLink<CONT>, ALLOC>::Accessor (const std::string& name)
  : Base (name)
{
}
 
 
/**
 * @brief Constructor.
 * @param name Name of this aux variable.
 * @param clsname The name of its associated class.  May be blank.
 *
 * The name -> auxid lookup is done here.
 */
template <class CONT, class ALLOC>
inline
Accessor<PackedLink<CONT>, ALLOC>::Accessor (const std::string& name,
                                             const std::string& clsname)
  : Base (name, clsname)
{
}
 
 
/**
 * @brief Constructor taking an auxid directly.
 * @param auxid ID for this auxiliary variable.
 *
 * Will throw @c SG::ExcAuxTypeMismatch if the types don't match.
 */
template <class CONT, class ALLOC>
inline
Accessor<PackedLink<CONT>, ALLOC>::Accessor (const SG::auxid_t auxid)
  : Base (auxid)
{
  // cppcheck-suppress missingReturn; false positive
}
 
 
/**
 * @brief Fetch the variable for one element.
 * @param e The element for which to fetch the variable.
 *
 * Will return an @c ElementLink proxy, which may be converted to
 * or assigned from an @c ElementLink.
 */
template <class CONT, class ALLOC>
template <IsAuxElement ELT>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::operator() (ELT& e) const -> ELProxy
{
  assert (e.container() != 0);
  return ELProxy (e.container()->template getData<PLink_t> (this->m_auxid, e.index()),
                  *e.container(),
                  this->m_auxid,
                  this->m_linkedAuxid);
}
 
 
/**
 * @brief Fetch the variable for one element.
 * @param container The container from which to fetch the variable.
 * @param index The index of the desired element.
 *
 * This allows retrieving aux data by container / index.
 *
 * Will return an @c ElementLink proxy, which may be converted to
 * or assigned from an @c ElementLink.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::operator() (AuxVectorData& container,
                                               size_t index) const -> ELProxy
{
  return ELProxy (container.template getData<PLink_t> (this->m_auxid, index),
                  container,
                  this->m_auxid,
                  this->m_linkedAuxid);
}
 
 
/**
 * @brief Set the variable for one element.
 * @param e The element for which to fetch the variable.
 * @param l The @c ElementLink to set.
 */
template <class CONT, class ALLOC>
inline
void Accessor<PackedLink<CONT>, ALLOC>::set (AuxElement& e, const Link_t& l) const
{
  set (*e.container(), e.index(), l);
}
 
 
/**
 * @brief Set the variable for one element.
 * @param container The container from which to fetch the variable.
 * @param index The index of the desired element.
 * @param l The @c ElementLink to set.
 */
template <class CONT, class ALLOC>
void Accessor<PackedLink<CONT>, ALLOC>::set (AuxVectorData& container,
                                             size_t index,
                                             const Link_t& x) const
{
  // Have to do this before creating the converter.
  PLink_t& ll = container.template getData<PLink_t> (this->m_auxid, index);
  detail::PackedLinkConverter<CONT> cnv (container,
                                         this->m_auxid,
                                         this->m_linkedAuxid);
  cnv.set (ll, x);
}
 
 
/**
 * @brief Get a pointer to the start of the array of @c PackedLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::getPackedLinkArray (AuxVectorData& container) const
  -> PLink_t*
{
  return reinterpret_cast<PLink_t*> (container.getDataArray (this->m_auxid));
}
 
 
/**
 * @brief Get a pointer to the start of the linked array of @c DataLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::getDataLinkArray (AuxVectorData& container) const
  -> DLink_t*
{
  return reinterpret_cast<DLink_t*>
    (container.getDataArray (this->m_linkedAuxid));
}
 
 
/**
 * @brief Get a span over the array of @c PackedLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::getPackedLinkSpan (AuxVectorData& container) const
  -> PackedLink_span
{
  // nb. AuxVectorData::getDataSpan is suitable only for const;
  // getDataArray may throw if the container is empty.
  size_t sz = container.size_v();
  PLink_t* beg = nullptr;
  if (sz) {
    beg = reinterpret_cast<PLink_t*> (container.getDataArray (this->m_auxid));
  }
  return PackedLink_span (beg, sz);
}
 
 
/**
 * @brief Get a span over the array of @c DataLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::getDataLinkSpan (AuxVectorData& container) const
  -> DataLink_span
{
  const AuxDataSpanBase sp = *container.getDataSpan (this->m_linkedAuxid);
  if (sp.size > 0) {
    // Accessibility check.  ??? Can we get rid of this?
    (void)container.getDataArray (this->m_linkedAuxid);
  }
  return DataLink_span (reinterpret_cast<DLink_t*>(sp.beg), sp.size);
}
 
 
 
/**
 * @brief Get a span of @c ElementLink proxies.
 * @param container The container from which to fetch the variable.
 *
 * The proxies may be converted to or assigned from @c ElementLink.
 */
template <class CONT, class ALLOC>
inline
auto
Accessor<PackedLink<CONT>, ALLOC>::getDataSpan (AuxVectorData& container) const
  -> span
{
  return span (getPackedLinkSpan(container),
               detail::PackedLinkConverter<CONT> (container,
                                                  this->m_auxid,
                                                  this->m_linkedAuxid));
}
 
 
/**
 * @brief Test to see if this variable exists in the store and is writable.
 * @param e An element of the container which to test the variable.
 */
template <class CONT, class ALLOC>
inline
bool
Accessor<PackedLink<CONT>, ALLOC>::isAvailableWritable (AuxElement& e) const
{
  return e.container() &&
    e.container()->isAvailableWritable (this->m_auxid) &&
    e.container()->isAvailableWritable (this->m_linkedAuxid);
}
 
 
/**
 * @brief Test to see if this variable exists in the store and is writable.
 * @param c The container which to test the variable.
 */
template <class CONT, class ALLOC>
inline
bool
Accessor<PackedLink<CONT>, ALLOC>::isAvailableWritable (AuxVectorData& c) const
{
  return c.isAvailableWritable (this->m_auxid) &&
    c.isAvailableWritable (this->m_linkedAuxid);
}
 
 
//************************************************************************
 
 
// To make the declarations a bit more readable.
#define ACCESSOR Accessor<std::vector<PackedLink<CONT>, VALLOC>, ALLOC>
 
 
/**
 * @brief Constructor.
 * @param name Name of this aux variable.
 *
 * The name -> auxid lookup is done here.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
ACCESSOR::Accessor (const std::string& name)
  : Base (name)
{
}
 
 
/**
 * @brief Constructor.
 * @param name Name of this aux variable.
 * @param clsname The name of its associated class.  May be blank.
 *
 * The name -> auxid lookup is done here.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
ACCESSOR::Accessor (const std::string& name,
                    const std::string& clsname)
  : Base (name, clsname)
{
}
 
 
/**
 * @brief Constructor taking an auxid directly.
 * @param auxid ID for this auxiliary variable.
 *
 * Will throw @c SG::ExcAuxTypeMismatch if the types don't match.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
ACCESSOR::Accessor (const SG::auxid_t auxid)
  : Base (auxid)
{
}
 
 
/**
 * @brief Fetch the variable for one element.
 * @param e The element for which to fetch the variable.
 *
 * This will return a range of @c ElementLink proxies.
 * These proxies may be converted to or assigned from @c ElementLink.
 */
template <class CONT, class ALLOC, class VALLOC>
template <IsAuxElement ELT>
auto
ACCESSOR::operator() (ELT& e) const -> elt_span
{
  assert (e.container() != 0);
  VElt_t* veltArr = getPackedLinkVectorArray(*e.container());
  return elt_span (veltArr[e.index()], *e.container(),
                   this->m_auxid,
                   this->m_linkedAuxid);
}
 
 
/**
 * @brief Fetch the variable for one element, as a non-const reference.
 * @param container The container from which to fetch the variable.
 * @param index The index of the desired element.
 *
 * This allows retrieving aux data by container / index.
 *
 * This will return a range of @c ElementLink proxies.
 * These proxies may be converted to or assigned from @c ElementLink.
 */
template <class CONT, class ALLOC, class VALLOC>
auto
ACCESSOR::operator() (AuxVectorData& container,
                      size_t index) const -> elt_span
{
  VElt_t* veltArr = getPackedLinkVectorArray(container);
  return elt_span (veltArr[index], container,
                   this->m_auxid,
                   this->m_linkedAuxid);
}
 
 
/**
 * @brief Set the variable for one element.
 * @param e The element for which to fetch the variable.
 * @param r The variable value to set, as a range over @c ElementLink.
 */
template <class CONT, class ALLOC, class VALLOC>
template <detail::ElementLinkRange<CONT> RANGE>
void ACCESSOR::set (AuxElement& e, const RANGE& r) const
{
  set (*e.container(), e.index(), r);
}
 
 
/**
 * @brief Set the variable for one element.
 * @param container The container for which to set the variable.
 * @param index The index of the desired element.
 * @param r The variable value to set, as a range over @c ElementLink.
 */
template <class CONT, class ALLOC, class VALLOC>
template <detail::ElementLinkRange<CONT> RANGE>
void ACCESSOR::set (AuxVectorData& container,
                    size_t index,
                    const RANGE& r) const
{
  detail::PackedLinkConverter<CONT> cnv (container,
                                         this->m_auxid,
                                         this->m_linkedAuxid);
  VElt_t& velt = container.template getData<VElt_t> (this->m_auxid, index);
  cnv.set (velt, r);
}
 
 
/**
 * @brief Get a pointer to the start of the array of vectors of @c PackedLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
auto
ACCESSOR::getPackedLinkVectorArray (AuxVectorData& container) const
  -> VElt_t*
{
  return reinterpret_cast<VElt_t*>
    (container.getDataArray (this->m_auxid));
}
 
 
/**
 * @brief Get a pointer to the start of the linked array of @c DataLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
auto
ACCESSOR::getDataLinkArray (AuxVectorData& container) const
  -> DLink_t*
{
  return reinterpret_cast<DLink_t*>
    (container.getDataArray (this->m_linkedAuxid));
}
 
 
/**
 * @brief Get a span over the vector of @c PackedLinks for a given element.
 * @param e The element for which to fetch the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
auto
ACCESSOR::getPackedLinkSpan (AuxElement& e) const
  -> PackedLink_span
{
  auto elt = reinterpret_cast<VElt_t*>
    (e.container()->getDataArray (this->m_auxid)) + e.index();
  return PackedLink_span (elt->data(), elt->size());
}
 
 
/**
 * @brief Get a span over the vector of @c PackedLinks for a given element.
 * @param container The container from which to fetch the variable.
 * @param index The index of the desired element.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
auto
ACCESSOR::getPackedLinkSpan (AuxVectorData& container,
                             size_t index) const
  -> PackedLink_span
{
  auto elt = reinterpret_cast<VElt_t*>
    (container.getDataArray (this->m_auxid)) + index;
  return PackedLink_span (elt->data(), elt->size());
}
 
 
/**
 * @brief Get a span over the vectors of @c PackedLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
auto
ACCESSOR::getPackedLinkVectorSpan (AuxVectorData& container) const
  -> PackedLinkVector_span
{
  auto beg = reinterpret_cast<VElt_t*> (container.getDataArray (this->m_auxid));
  return PackedLinkVector_span (beg, container.size_v());
}
 
/**
 * @brief Get a span over the array of @c DataLinks.
 * @param container The container from which to fetch the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
auto
ACCESSOR::getDataLinkSpan (AuxVectorData& container) const
  -> DataLink_span
{
  const AuxDataSpanBase* sp = container.getDataSpan (this->m_linkedAuxid);
  return DataLink_span (reinterpret_cast<DLink_t*>(sp->beg), sp->size);
}
 
/**
 * @brief Get a span over spans of @c ElementLink proxies.
 * @param container The container from which to fetch the variable.
 *
 * The individual proxies may be converted to or assigned from @c ElementLink.
 * Each element may also be assigned from a range of @c ElementLink,
 * or converted to a vector of @c ElementLink.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
auto
ACCESSOR::getDataSpan (AuxVectorData& container) const
  -> span
{
  return span (getPackedLinkVectorSpan(container),
               ELSpanConverter (container, this->m_auxid, this->m_linkedAuxid));
}
 
 
/**
 * @brief Test to see if this variable exists in the store and is writable.
 * @param e An element of the container in which to test the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
bool
ACCESSOR::isAvailableWritable (AuxElement& e) const
{
  return e.container() &&
    e.container()->isAvailableWritable (this->m_auxid) &&
    e.container()->isAvailableWritable (this->m_linkedAuxid);
}
 
 
/**
 * @brief Test to see if this variable exists in the store and is writable.
 * @param c The container in which to test the variable.
 */
template <class CONT, class ALLOC, class VALLOC>
inline
bool
ACCESSOR::isAvailableWritable (AuxVectorData& c) const
{
  return c.isAvailableWritable (this->m_auxid) &&
    c.isAvailableWritable (this->m_linkedAuxid);
}
 
 
#undef ACCESSOR
 
 
} // namespace SG