//============================================================================
//  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 2016 Sandia Corporation.
//  Copyright 2016 UT-Battelle, LLC.
//  Copyright 2016 Los Alamos National Security.
//
//  Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
//  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.
//============================================================================
#ifndef vtk_m_exec_arg_ThreadIndicesReduceByKey_h
#define vtk_m_exec_arg_ThreadIndicesReduceByKey_h

#include <vtkm/exec/arg/ThreadIndicesBasic.h>

#include <vtkm/exec/internal/ReduceByKeyLookup.h>

namespace vtkm {
namespace exec {
namespace arg {

/// \brief Container for thread indices in a reduce by key invocation.
///
/// This specialization of \c ThreadIndices adds extra indices that deal with a
/// reduce by key. In particular, it save the indices used to map from a unique
/// key index to the group of input values that has that key associated with
/// it.
///
class ThreadIndicesReduceByKey : public vtkm::exec::arg::ThreadIndicesBasic
{
  using Superclass = vtkm::exec::arg::ThreadIndicesBasic;

public:
  template<typename P1, typename P2, typename P3>
  VTKM_EXEC
  ThreadIndicesReduceByKey(
      vtkm::Id threadIndex,
      vtkm::Id inIndex,
      vtkm::IdComponent visitIndex,
      const vtkm::exec::internal::ReduceByKeyLookup<P1,P2,P3> &keyLookup,
      vtkm::Id globalThreadIndexOffset=0)
    : Superclass(threadIndex, inIndex, visitIndex, globalThreadIndexOffset),
      ValueOffset(keyLookup.Offsets.Get(inIndex)),
      NumberOfValues(keyLookup.Counts.Get(inIndex))
  {  }

  VTKM_EXEC
  vtkm::Id GetValueOffset() const
  {
    return this->ValueOffset;
  }

  VTKM_EXEC
  vtkm::IdComponent GetNumberOfValues() const
  {
    return this->NumberOfValues;
  }

private:
  vtkm::Id ValueOffset;
  vtkm::IdComponent NumberOfValues;
};

}
}
} // namespace vtkm::exec::arg

#endif //vtk_m_exec_arg_ThreadIndicesReduceByKey_h
