vtk-m/vtkm/cont/ArrayPortal.h

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3.1 KiB
C++

//============================================================================
// 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 Sandia Corporation.
// Copyright 2014 UT-Battelle, LLC.
// Copyright 2014 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_ArrayPortal_h
#define vtk_m_cont_ArrayPortal_h
#include <vtkm/Types.h>
namespace vtkm {
namespace cont {
#ifdef VTKM_DOXYGEN_ONLY
/// \brief A class that points to and access and array of data.
///
/// The ArrayPortal class itself does not exist; this code is provided for
/// documentation purposes only.
///
/// An ArrayPortal object acts like a pointer to a random-access container
/// (that is, an array) and also lets you set and get values in that array. In
/// many respects an ArrayPortal is similar in concept to that of iterators but
/// with a much simpler interface and no internal concept of position.
/// Otherwise, ArrayPortal objects may be passed and copied around so that
/// multiple entities may be accessing the same array.
///
/// An ArrayPortal differs from an ArrayHandle in that the ArrayPortal is a
/// much lighterweight object and that it does not manage things like
/// allocation and control/execution sharing. An ArrayPortal also differs from
/// a Storage in that it does not actually contain the data but rather
/// points to it. In this way the ArrayPortal can be copied and passed and
/// still point to the same data.
///
/// Most VTKm users generally do not need to do much or anything with
/// ArrayPortal objects. It is mostly an internal mechanism. However, an
/// ArrayPortal can be used to pass constant input data to an ArrayHandle.
///
/// Although this documentation is given for the control environment, there are
/// instances of an identical concept in the execution environment, although
/// some features are missing there.
///
template<typename T>
class ArrayPortal
{
public:
/// The type of each value in the array.
///
typedef T ValueType;
/// The total number of values in the array. They are index from 0 to
/// GetNumberOfValues()-1.
///
VTKM_CONT_EXPORT
vtkm::Id GetNumberOfValues() const;
/// Gets a value from the array.
///
VTKM_CONT_EXPORT
ValueType Get(vtkm::Id index) const;
/// Sets a value in the array. This function may not exist for an ArrayPortal
/// pointing to a const array.
///
VTKM_CONT_EXPORT
void Set(vtkm::Id index, const ValueType &value) const;
};
#endif // VTKM_DOXYGEN_ONLY
}
} // namespace vtkm::cont
#endif //vtk_m_cont_ArrayPortal_h