iterator_utilities.hpp

/*
 * Copyright (c) 2021-2024, NVIDIA CORPORATION.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
 
#include <cudf/detail/iterator.cuh>
#include <cudf/types.hpp>
#include <cudf/utilities/export.hpp>
 
#include <thrust/iterator/constant_iterator.h>
#include <thrust/iterator/transform_iterator.h>
 
#include <iterator>
 
namespace CUDF_EXPORT cudf {
namespace test {
namespace iterators {
template <typename Iter>
[[maybe_unused]] static auto nulls_at(Iter index_start, Iter index_end)
{
  using index_type = typename std::iterator_traits<Iter>::value_type;
 
  return cudf::detail::make_counting_transform_iterator(
    0, [indices = std::vector<index_type>{index_start, index_end}](auto i) {
      return std::find(indices.cbegin(), indices.cend(), i) == indices.cend();
    });
}
 
[[maybe_unused]] static auto nulls_at(std::vector<cudf::size_type> const& indices)
{
  return nulls_at(indices.cbegin(), indices.cend());
}
 
[[maybe_unused]] static auto null_at(cudf::size_type index)
{
  return nulls_at(std::vector<cudf::size_type>{index});
}
 
[[maybe_unused]] static auto all_nulls() { return thrust::make_constant_iterator(false); }
 
[[maybe_unused]] static auto no_nulls() { return thrust::make_constant_iterator(true); }
 
template <class T>
[[maybe_unused]] static auto nulls_from_nullptrs(std::vector<T const*> const& ptrs)
{
  return thrust::make_transform_iterator(ptrs.begin(), [](auto ptr) { return ptr != nullptr; });
}
 
}  // namespace iterators
}  // namespace test
}  // namespace CUDF_EXPORT cudf