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//============================================================================

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//============================================================================
// Copyright (c) 2018, The Regents of the University of California, through
// Lawrence Berkeley National Laboratory (subject to receipt of any required approvals
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//=============================================================================
//  The PPP2 algorithm and software were jointly developed by
//  Hamish Carr (University of Leeds), Gunther H. Weber (LBNL), and
//  Oliver Ruebel (LBNL)
//==============================================================================

#ifndef viskores_worklet_contourtree_distributed_hierarchical_augmenter_fill_empty_iteration_worklet_h
#define viskores_worklet_contourtree_distributed_hierarchical_augmenter_fill_empty_iteration_worklet_h

#include <viskores/filter/scalar_topology/worklet/contourtree_augmented/Types.h>
#include <viskores/worklet/WorkletMapField.h>

namespace viskores
{
namespace worklet
{
namespace contourtree_distributed
{
namespace hierarchical_augmenter
{

// Worklet for a rare case where an iteration has no supernode
// need to update the FirstSupernodePerIteration array to avoid crash
class FillEmptyIterationWorklet : public viskores::worklet::WorkletMapField
{
public:
  using ControlSignature = void(
    WholeArrayInOut augmentedTreeFirstSupernodePerIteration // input/output
  );
  using ExecutionSignature = void(InputIndex, _1);
  using InputDomain = _1;

  VISKORES_EXEC_CONT
  FillEmptyIterationWorklet() {}

  /// operator() of the worklet
  template <typename InOutFieldPortalType>
  VISKORES_EXEC void operator()(const viskores::Id& inputIndex,
                                InOutFieldPortalType& firstSupernodePerIteration) const
  {
    if (inputIndex == 0 || inputIndex == firstSupernodePerIteration.GetNumberOfValues() - 1)
      return;
    if (firstSupernodePerIteration.Get(inputIndex) == 0)
    {
      viskores::Id nextSupernode = firstSupernodePerIteration.Get(inputIndex + 1);
      firstSupernodePerIteration.Set(inputIndex, nextSupernode);
    }
  } // operator()()
};  // FillEmptyIterationWorklet

} // namespace hierarchical_augmenter
} // namespace contourtree_distributed
} // namespace worklet
} // namespace viskores

#endif
