ArrayCopyDevice.h

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//============================================================================
//  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.
//============================================================================
#ifndef vtk_m_cont_ArrayCopyDevice_h
#define vtk_m_cont_ArrayCopyDevice_h
 
#include <vtkm/cont/Algorithm.h>
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/DeviceAdapterTag.h>
#include <vtkm/cont/ErrorExecution.h>
#include <vtkm/cont/Logging.h>
#include <vtkm/cont/UnknownArrayHandle.h>
 
#include <vtkm/cont/vtkm_cont_export.h>
 
// TODO: When virtual arrays are available, compile the implementation in a .cxx/.cu file. Common
// arrays are copied directly but anything else would be copied through virtual methods.
 
namespace vtkm
{
namespace cont
{
 
namespace detail
{
 
template <typename T1, typename S1, typename T2, typename S2>
VTKM_CONT void ArrayCopyImpl(const vtkm::cont::ArrayHandle<T1, S1>& source,
                             vtkm::cont::ArrayHandle<T2, S2>& destination)
{
  VTKM_STATIC_ASSERT((!std::is_same<T1, T2>::value || !std::is_same<S1, S2>::value));
 
  // Current implementation of Algorithm::Copy will first try to copy on devices where the
  // data is already available.
  vtkm::cont::Algorithm::Copy(source, destination);
}
 
template <typename T, typename S>
VTKM_CONT void ArrayCopyImpl(const vtkm::cont::ArrayHandle<T, S>& source,
                             vtkm::cont::ArrayHandle<T, S>& destination)
{
  destination.DeepCopyFrom(source);
}
 
} // namespace detail
 
template <typename InValueType, typename InStorage, typename OutValueType, typename OutStorage>
VTKM_CONT void ArrayCopyDevice(const vtkm::cont::ArrayHandle<InValueType, InStorage>& source,
                               vtkm::cont::ArrayHandle<OutValueType, OutStorage>& destination)
{
  using InArrayType = vtkm::cont::ArrayHandle<InValueType, InStorage>;
  using OutArrayType = vtkm::cont::ArrayHandle<OutValueType, OutStorage>;
  using SameTypes = std::is_same<InArrayType, OutArrayType>;
  using IsWritable = vtkm::cont::internal::IsWritableArrayHandle<OutArrayType>;
 
  // There are three cases handled here:
  // 1. The arrays are the same type:
  //    -> Deep copy the buffers and the Storage object
  // 2. The arrays are different and the output is writable:
  //    -> Do element-wise copy
  // 3. The arrays are different and the output is not writable:
  //    -> fail (cannot copy)
 
  // Give a nice error message for case 3:
  VTKM_STATIC_ASSERT_MSG(IsWritable::value || SameTypes::value,
                         "Cannot copy to a read-only array with a different "
                         "type than the source.");
 
  // Static dispatch cases 1 & 2
  detail::ArrayCopyImpl(source, destination);
}
 
 
}
} // namespace vtkm::cont
 
#endif //vtk_m_cont_ArrayCopyDevice_h