Function GetCastToHalfFloat

cpp/src/arrow/compute/kernels/scalar_cast_numeric.cc:1036–1060

}

std::shared_ptr<CastFunction> GetCastToHalfFloat() {
  // HalfFloat is a bit brain-damaged for now
  auto func = std::make_shared<CastFunction>("func", Type::HALF_FLOAT);
  AddCommonCasts(Type::HALF_FLOAT, float16(), func.get());

  // Casts from integer to floating point
  for (const std::shared_ptr<DataType>& in_ty : IntTypes()) {
    DCHECK_OK(func->AddKernel(in_ty->id(), {in_ty},
                              TypeTraits<HalfFloatType>::type_singleton(),
                              CastIntegerToFloating));
  }

  // Cast from other strings to half float.
  for (const std::shared_ptr<DataType>& in_ty : BaseBinaryTypes()) {
    auto exec = GenerateVarBinaryBase<CastFunctor, HalfFloatType>(*in_ty);
    DCHECK_OK(func->AddKernel(in_ty->id(), {in_ty},
                              TypeTraits<HalfFloatType>::type_singleton(), exec));
  }

  DCHECK_OK(func.get()->AddKernel(Type::FLOAT, {InputType(Type::FLOAT)}, float16(),
                                  CastFloatingToFloating));
  DCHECK_OK(func.get()->AddKernel(Type::DOUBLE, {InputType(Type::DOUBLE)}, float16(),
                                  CastFloatingToFloating));
  return func;
}

struct NullExtensionTypeMatcher : public TypeMatcher {
  ~NullExtensionTypeMatcher() override = default;