//============================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt for details.
//  This software is distributed WITHOUT ANY WARRANTY; without even
//  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
//  PURPOSE.  See the above copyright notice for more information.
//
//  Copyright 2014 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
//  Copyright 2014 UT-Battelle, LLC.
//  Copyright 2014 Los Alamos National Security.
//
//  Under the terms of Contract DE-NA0003525 with NTESS,
//  the U.S. Government retains certain rights in this software.
//
//  Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
//  Laboratory (LANL), the U.S. Government retains certain rights in
//  this software.
//============================================================================
// Copyright (c) 2018, The Regents of the University of California, through
// Lawrence Berkeley National Laboratory (subject to receipt of any required approvals
// from the U.S. Dept. of Energy).  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// (1) Redistributions of source code must retain the above copyright notice, this
//     list of conditions and the following disclaimer.
//
// (2) Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//
// (3) Neither the name of the University of California, Lawrence Berkeley National
//     Laboratory, U.S. Dept. of Energy nor the names of its contributors may be
//     used to endorse or promote products derived from this software without
//     specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//
//=============================================================================
//
//  This code is an extension of the algorithm presented in the paper:
//  Parallel Peak Pruning for Scalable SMP Contour Tree Computation.
//  Hamish Carr, Gunther Weber, Christopher Sewell, and James Ahrens.
//  Proceedings of the IEEE Symposium on Large Data Analysis and Visualization
//  (LDAV), October 2016, Baltimore, Maryland.
//
//  The PPP2 algorithm and software were jointly developed by
//  Hamish Carr (University of Leeds), Gunther H. Weber (LBNL), and
//  Oliver Ruebel (LBNL)
//==============================================================================

#ifndef vtk_m_worklet_contourtree_augmented_contourtree_mesh_inc_combined_vector_different_from_next_h
#define vtk_m_worklet_contourtree_augmented_contourtree_mesh_inc_combined_vector_different_from_next_h

#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/ExecutionAndControlObjectBase.h>
#include <vtkm/worklet/contourtree_augmented/Types.h>

namespace vtkm
{
namespace worklet
{
namespace contourtree_augmented
{
namespace mesh_dem_contourtree_mesh_inc
{

/// Decorator to compute if element i is different from element i+1 in an arrays. The
/// resulting array should hence be 1 element shorter than the input arrays
class CombinedVectorDifferentFromNextDecoratorImpl
{
public:
  template <typename Portal1Type, typename Portal2Type, typename Portal3Type>
  struct Functor
  {
    Portal1Type OverallSortOrderPortal;
    Portal2Type ThisGlobalMeshIndex;
    Portal3Type OtherGlobalMeshIndex;

    VTKM_EXEC_CONT inline vtkm::Id GetGlobalMeshIndex(vtkm::Id idx) const
    {
      return vtkm::worklet::contourtree_augmented::IsThis(idx)
        ? this->ThisGlobalMeshIndex.Get(MaskedIndex(idx))
        : this->OtherGlobalMeshIndex.Get(MaskedIndex(idx));
    }

    VTKM_EXEC_CONT vtkm::Id operator()(vtkm::Id i) const
    {
      vtkm::Id currGlobalIdx = this->GetGlobalMeshIndex(this->OverallSortOrderPortal.Get(i));
      vtkm::Id nextGlobalIdx = this->GetGlobalMeshIndex(this->OverallSortOrderPortal.Get(i + 1));
      return (currGlobalIdx != nextGlobalIdx) ? 1 : 0;
    }
  };

  template <typename PT1, typename PT2, typename PT3>
  Functor<PT1, PT2, PT3> CreateFunctor(PT1 OverallSortOrderPortal,
                                       PT2 ThisGlobalMeshIndex,
                                       PT3 OtherGlobalMeshIndex) const
  {
    return { OverallSortOrderPortal, ThisGlobalMeshIndex, OtherGlobalMeshIndex };
  }
};

} // namespace mesh_dem_contourtree_mesh_inc
} // namespace contourtree_augmented
} // namespace worklet
} // namespace vtkm

#endif
