//=============================================================================
//
//  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 2015 Sandia Corporation.
//  Copyright 2015 UT-Battelle, LLC.
//  Copyright 2015 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_cont_ArrayHandleCast_h
#define vtk_m_cont_ArrayHandleCast_h

#include <vtkm/cont/ArrayHandleTransform.h>

namespace vtkm {
namespace cont {

namespace internal {

template<typename FromType, typename ToType>
struct VTKM_ALWAYS_EXPORT Cast
{
  VTKM_EXEC_CONT
  ToType operator()(const FromType &val) const
  {
    return static_cast<ToType>(val);
  }
};

} // namespace internal


/// \brief Cast the values of an array to the specified type, on demand.
///
/// ArrayHandleCast is a specialization of ArrayHandleTransform. Given an ArrayHandle
/// and a type, it creates a new handle that returns the elements of the array cast
/// to the specified type.
///
template <typename T, typename ArrayHandleType>
class ArrayHandleCast :
  public vtkm::cont::ArrayHandleTransform<
    T,
    ArrayHandleType,
    internal::Cast<typename ArrayHandleType::ValueType, T>,
    internal::Cast<T, typename ArrayHandleType::ValueType> >
{
public:
  VTKM_ARRAY_HANDLE_SUBCLASS(
    ArrayHandleCast,
    (ArrayHandleCast<T, ArrayHandleType>),
    (vtkm::cont::ArrayHandleTransform<
     T,
     ArrayHandleType,
     internal::Cast<typename ArrayHandleType::ValueType, T>,
     internal::Cast<T, typename ArrayHandleType::ValueType> >));

  ArrayHandleCast(const ArrayHandleType &handle)
    : Superclass(handle)
  { }
};

/// make_ArrayHandleCast is convenience function to generate an
/// ArrayHandleCast.
///
template <typename T, typename HandleType>
VTKM_CONT
ArrayHandleCast<T, HandleType> make_ArrayHandleCast(const HandleType &handle,
                                                    const T& = T())
{
  return ArrayHandleCast<T, HandleType>(handle);
}

}
} // namespace vtkm::cont

#endif // vtk_m_cont_ArrayHandleCast_h
