ArrayHandleConstant.h

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//============================================================================
//  The contents of this file are covered by the Viskores license. See
//  LICENSE.txt for details.
//
//  By contributing to this file, all contributors agree to the Developer
//  Certificate of Origin Version 1.1 (DCO 1.1) as stated in DCO.txt.
//============================================================================
 
//============================================================================
//  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 viskores_cont_ArrayHandleConstant_h
#define viskores_cont_ArrayHandleConstant_h
 
#include <viskores/cont/ArrayExtractComponent.h>
#include <viskores/cont/ArrayHandleImplicit.h>
 
#include <viskores/cont/internal/ArrayRangeComputeUtils.h>
 
#include <viskores/Range.h>
#include <viskores/VecFlat.h>
#include <viskores/VectorAnalysis.h>
 
namespace viskores
{
namespace cont
{
 
struct VISKORES_ALWAYS_EXPORT StorageTagConstant
{
};
 
namespace internal
{
 
template <typename ValueType>
struct VISKORES_ALWAYS_EXPORT ConstantFunctor
{
  VISKORES_EXEC_CONT
  ConstantFunctor(const ValueType& value = ValueType())
    : Value(value)
  {
  }
 
  VISKORES_EXEC_CONT
  ValueType operator()(viskores::Id viskoresNotUsed(index)) const { return this->Value; }
 
private:
  ValueType Value;
};
 
template <typename T>
using StorageTagConstantSuperclass =
  typename viskores::cont::ArrayHandleImplicit<ConstantFunctor<T>>::StorageTag;
 
template <typename T>
struct Storage<T, viskores::cont::StorageTagConstant> : Storage<T, StorageTagConstantSuperclass<T>>
{
};
 
} // namespace internal
 
template <typename T>
class ArrayHandleConstant
  : public viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>
{
public:
  VISKORES_ARRAY_HANDLE_SUBCLASS(
    ArrayHandleConstant,
    (ArrayHandleConstant<T>),
    (viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>));
 
  VISKORES_CONT
  ArrayHandleConstant(T value, viskores::Id numberOfValues = 0)
    : Superclass(internal::FunctorToArrayHandleImplicitBuffers(internal::ConstantFunctor<T>(value),
                                                               numberOfValues))
  {
  }
 
  VISKORES_CONT T GetValue() const { return this->ReadPortal().GetFunctor()(0); }
};
 
template <typename T>
viskores::cont::ArrayHandleConstant<T> make_ArrayHandleConstant(T value,
                                                                viskores::Id numberOfValues)
{
  return viskores::cont::ArrayHandleConstant<T>(value, numberOfValues);
}
 
namespace internal
{
 
template <>
struct VISKORES_CONT_EXPORT ArrayExtractComponentImpl<viskores::cont::StorageTagConstant>
{
  template <typename T>
  VISKORES_CONT auto operator()(
    const viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>& src,
    viskores::IdComponent componentIndex,
    viskores::CopyFlag allowCopy) const
  {
    if (allowCopy != viskores::CopyFlag::On)
    {
      throw viskores::cont::ErrorBadValue(
        "Cannot extract component of ArrayHandleConstant without copying. "
        "(However, the whole array does not need to be copied.)");
    }
 
    viskores::cont::ArrayHandleConstant<T> srcArray = src;
 
    viskores::VecFlat<T> vecValue{ srcArray.GetValue() };
 
    // Make a basic array with one entry (the constant value).
    auto basicArray = viskores::cont::make_ArrayHandle({ vecValue[componentIndex] });
 
    // Set up a modulo = 1 so all indices go to this one value.
    return viskores::cont::make_ArrayHandleStride(basicArray, src.GetNumberOfValues(), 1, 0, 1, 1);
  }
};
 
template <typename S>
struct ArrayRangeComputeImpl;
 
template <>
struct VISKORES_CONT_EXPORT ArrayRangeComputeImpl<viskores::cont::StorageTagConstant>
{
  template <typename T>
  VISKORES_CONT viskores::cont::ArrayHandle<viskores::Range> operator()(
    const viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>& input,
    const viskores::cont::ArrayHandle<viskores::UInt8>& maskArray,
    bool computeFiniteRange,
    viskores::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 = viskores::make_VecFlat(input.ReadPortal().Get(0));
 
    viskores::cont::ArrayHandle<viskores::Range> result;
    result.Allocate(value.GetNumberOfComponents());
    auto resultPortal = result.WritePortal();
    for (viskores::IdComponent index = 0; index < value.GetNumberOfComponents(); ++index)
    {
      auto comp = static_cast<viskores::Float64>(value[index]);
      if (allMasked || (computeFiniteRange && !viskores::IsFinite(comp)))
      {
        resultPortal.Set(index, viskores::Range{});
      }
      else
      {
        resultPortal.Set(index, viskores::Range{ comp, comp });
      }
    }
    return result;
  }
};
 
template <typename S>
struct ArrayRangeComputeMagnitudeImpl;
 
template <>
struct VISKORES_CONT_EXPORT ArrayRangeComputeMagnitudeImpl<viskores::cont::StorageTagConstant>
{
  template <typename T>
  VISKORES_CONT viskores::Range operator()(
    const viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>& input,
    const viskores::cont::ArrayHandle<viskores::UInt8>& maskArray,
    bool computeFiniteRange,
    viskores::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 viskores::Range{};
      }
    }
 
    auto value = input.ReadPortal().Get(0);
    viskores::Float64 rangeValue = viskores::Magnitude(viskores::make_VecFlat(value));
    return (computeFiniteRange && !viskores::IsFinite(rangeValue))
      ? viskores::Range{}
      : viskores::Range{ rangeValue, rangeValue };
  }
};
 
} // namespace internal
 
}
} // viskores::cont
 
//=============================================================================
// Specializations of serialization related classes
namespace viskores
{
namespace cont
{
 
template <typename T>
struct SerializableTypeString<viskores::cont::ArrayHandleConstant<T>>
{
  static VISKORES_CONT const std::string& Get()
  {
    static std::string name = "AH_Constant<" + SerializableTypeString<T>::Get() + ">";
    return name;
  }
};
 
template <typename T>
struct SerializableTypeString<viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>>
  : SerializableTypeString<viskores::cont::ArrayHandleConstant<T>>
{
};
}
} // viskores::cont
 
namespace mangled_diy_namespace
{
 
template <typename T>
struct Serialization<viskores::cont::ArrayHandleConstant<T>>
{
private:
  using Type = viskores::cont::ArrayHandleConstant<T>;
  using BaseType = viskores::cont::ArrayHandle<typename Type::ValueType, typename Type::StorageTag>;
 
public:
  static VISKORES_CONT void save(BinaryBuffer& bb, const BaseType& obj)
  {
    viskoresdiy::save(bb, obj.GetNumberOfValues());
    viskoresdiy::save(bb, obj.ReadPortal().Get(0));
  }
 
  static VISKORES_CONT void load(BinaryBuffer& bb, BaseType& obj)
  {
    viskores::Id count = 0;
    viskoresdiy::load(bb, count);
 
    T value;
    viskoresdiy::load(bb, value);
 
    obj = viskores::cont::make_ArrayHandleConstant(value, count);
  }
};
 
template <typename T>
struct Serialization<viskores::cont::ArrayHandle<T, viskores::cont::StorageTagConstant>>
  : Serialization<viskores::cont::ArrayHandleConstant<T>>
{
};
 
} // diy
 
#endif //viskores_cont_ArrayHandleConstant_h