ArrayHandleConstant.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_ArrayHandleConstant_h
#define vtk_m_cont_ArrayHandleConstant_h
 
#include <vtkm/cont/ArrayExtractComponent.h>
#include <vtkm/cont/ArrayHandleImplicit.h>
 
#include <vtkm/cont/internal/ArrayRangeComputeUtils.h>
 
#include <vtkm/Range.h>
#include <vtkm/VecFlat.h>
#include <vtkm/VectorAnalysis.h>
 
namespace vtkm
{
namespace cont
{
 
struct VTKM_ALWAYS_EXPORT StorageTagConstant
{
};
 
namespace internal
{
 
template <typename ValueType>
struct VTKM_ALWAYS_EXPORT ConstantFunctor
{
  VTKM_EXEC_CONT
  ConstantFunctor(const ValueType& value = ValueType())
    : Value(value)
  {
  }
 
  VTKM_EXEC_CONT
  ValueType operator()(vtkm::Id vtkmNotUsed(index)) const { return this->Value; }
 
private:
  ValueType Value;
};
 
template <typename T>
using StorageTagConstantSuperclass =
  typename vtkm::cont::ArrayHandleImplicit<ConstantFunctor<T>>::StorageTag;
 
template <typename T>
struct Storage<T, vtkm::cont::StorageTagConstant> : Storage<T, StorageTagConstantSuperclass<T>>
{
};
 
} // namespace internal
 
template <typename T>
class ArrayHandleConstant : public vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>
{
public:
  VTKM_ARRAY_HANDLE_SUBCLASS(ArrayHandleConstant,
                             (ArrayHandleConstant<T>),
                             (vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>));
 
  VTKM_CONT
  ArrayHandleConstant(T value, vtkm::Id numberOfValues = 0)
    : Superclass(internal::FunctorToArrayHandleImplicitBuffers(internal::ConstantFunctor<T>(value),
                                                               numberOfValues))
  {
  }
 
  VTKM_CONT T GetValue() const { return this->ReadPortal().GetFunctor()(0); }
};
 
template <typename T>
vtkm::cont::ArrayHandleConstant<T> make_ArrayHandleConstant(T value, vtkm::Id numberOfValues)
{
  return vtkm::cont::ArrayHandleConstant<T>(value, numberOfValues);
}
 
namespace internal
{
 
template <>
struct VTKM_CONT_EXPORT ArrayExtractComponentImpl<vtkm::cont::StorageTagConstant>
{
  template <typename T>
  VTKM_CONT auto operator()(const vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>& src,
                            vtkm::IdComponent componentIndex,
                            vtkm::CopyFlag allowCopy) const
  {
    if (allowCopy != vtkm::CopyFlag::On)
    {
      throw vtkm::cont::ErrorBadValue(
        "Cannot extract component of ArrayHandleConstant without copying. "
        "(However, the whole array does not need to be copied.)");
    }
 
    vtkm::cont::ArrayHandleConstant<T> srcArray = src;
 
    vtkm::VecFlat<T> vecValue{ srcArray.GetValue() };
 
    // Make a basic array with one entry (the constant value).
    auto basicArray = vtkm::cont::make_ArrayHandle({ vecValue[componentIndex] });
 
    // Set up a modulo = 1 so all indices go to this one value.
    return vtkm::cont::make_ArrayHandleStride(basicArray, src.GetNumberOfValues(), 1, 0, 1, 1);
  }
};
 
template <typename S>
struct ArrayRangeComputeImpl;
 
template <>
struct VTKM_CONT_EXPORT ArrayRangeComputeImpl<vtkm::cont::StorageTagConstant>
{
  template <typename T>
  VTKM_CONT vtkm::cont::ArrayHandle<vtkm::Range> operator()(
    const vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>& input,
    const vtkm::cont::ArrayHandle<vtkm::UInt8>& maskArray,
    bool computeFiniteRange,
    vtkm::cont::DeviceAdapterId devId) const
  {
    bool allMasked = false;
    if (maskArray.GetNumberOfValues() != 0)
    {
      // Find if there is atleast one value that is not masked
      auto ids = GetFirstAndLastUnmaskedIndices(maskArray, devId);
      allMasked = (ids[1] < ids[0]);
    }
 
    auto value = vtkm::make_VecFlat(input.ReadPortal().Get(0));
 
    vtkm::cont::ArrayHandle<vtkm::Range> result;
    result.Allocate(value.GetNumberOfComponents());
    auto resultPortal = result.WritePortal();
    for (vtkm::IdComponent index = 0; index < value.GetNumberOfComponents(); ++index)
    {
      auto comp = static_cast<vtkm::Float64>(value[index]);
      if (allMasked || (computeFiniteRange && !vtkm::IsFinite(comp)))
      {
        resultPortal.Set(index, vtkm::Range{});
      }
      else
      {
        resultPortal.Set(index, vtkm::Range{ comp, comp });
      }
    }
    return result;
  }
};
 
template <typename S>
struct ArrayRangeComputeMagnitudeImpl;
 
template <>
struct VTKM_CONT_EXPORT ArrayRangeComputeMagnitudeImpl<vtkm::cont::StorageTagConstant>
{
  template <typename T>
  VTKM_CONT vtkm::Range operator()(
    const vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>& input,
    const vtkm::cont::ArrayHandle<vtkm::UInt8>& maskArray,
    bool computeFiniteRange,
    vtkm::cont::DeviceAdapterId devId) const
  {
    if (maskArray.GetNumberOfValues() != 0)
    {
      // Find if there is atleast one value that is not masked
      auto ids = GetFirstAndLastUnmaskedIndices(maskArray, devId);
      if (ids[1] < ids[0])
      {
        return vtkm::Range{};
      }
    }
 
    auto value = input.ReadPortal().Get(0);
    vtkm::Float64 rangeValue = vtkm::Magnitude(vtkm::make_VecFlat(value));
    return (computeFiniteRange && !vtkm::IsFinite(rangeValue))
      ? vtkm::Range{}
      : vtkm::Range{ rangeValue, rangeValue };
  }
};
 
} // namespace internal
 
}
} // vtkm::cont
 
//=============================================================================
// Specializations of serialization related classes
namespace vtkm
{
namespace cont
{
 
template <typename T>
struct SerializableTypeString<vtkm::cont::ArrayHandleConstant<T>>
{
  static VTKM_CONT const std::string& Get()
  {
    static std::string name = "AH_Constant<" + SerializableTypeString<T>::Get() + ">";
    return name;
  }
};
 
template <typename T>
struct SerializableTypeString<vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>>
  : SerializableTypeString<vtkm::cont::ArrayHandleConstant<T>>
{
};
}
} // vtkm::cont
 
namespace mangled_diy_namespace
{
 
template <typename T>
struct Serialization<vtkm::cont::ArrayHandleConstant<T>>
{
private:
  using Type = vtkm::cont::ArrayHandleConstant<T>;
  using BaseType = vtkm::cont::ArrayHandle<typename Type::ValueType, typename Type::StorageTag>;
 
public:
  static VTKM_CONT void save(BinaryBuffer& bb, const BaseType& obj)
  {
    vtkmdiy::save(bb, obj.GetNumberOfValues());
    vtkmdiy::save(bb, obj.ReadPortal().Get(0));
  }
 
  static VTKM_CONT void load(BinaryBuffer& bb, BaseType& obj)
  {
    vtkm::Id count = 0;
    vtkmdiy::load(bb, count);
 
    T value;
    vtkmdiy::load(bb, value);
 
    obj = vtkm::cont::make_ArrayHandleConstant(value, count);
  }
};
 
template <typename T>
struct Serialization<vtkm::cont::ArrayHandle<T, vtkm::cont::StorageTagConstant>>
  : Serialization<vtkm::cont::ArrayHandleConstant<T>>
{
};
 
} // diy
 
#endif //vtk_m_cont_ArrayHandleConstant_h