Function ListViewArrayFromArrays

cpp/src/arrow/array/array_nested.cc:145–213

template <typename TYPE>
Result<std::shared_ptr<typename TypeTraits<TYPE>::ArrayType>> ListViewArrayFromArrays(
    std::shared_ptr<DataType> type, const Array& offsets, const Array& sizes,
    const Array& values, MemoryPool* pool, std::shared_ptr<Buffer> null_bitmap = NULLPTR,
    int64_t null_count = kUnknownNullCount) {
  using offset_type = typename TYPE::offset_type;
  using ArrayType = typename TypeTraits<TYPE>::ArrayType;
  using OffsetArrowType = typename CTypeTraits<offset_type>::ArrowType;

  if (offsets.type_id() != OffsetArrowType::type_id) {
    return Status::TypeError("List offsets must be ", OffsetArrowType::type_name());
  }

  if (sizes.length() != offsets.length() && sizes.length() != offsets.length() - 1) {
    return Status::Invalid(
        "List sizes must have the same length as offsets or one less than offsets");
  }
  if (sizes.type_id() != OffsetArrowType::type_id) {
    return Status::TypeError("List sizes must be ", OffsetArrowType::type_name());
  }

  if (offsets.offset() != sizes.offset()) {
    return Status::Invalid("List offsets and sizes must have the same offset");
  }
  const int64_t array_offset = sizes.offset();

  if (null_bitmap) {
    if (offsets.null_count() > 0 || sizes.null_count() > 0) {
      return Status::Invalid(
          "Ambiguous to specify both validity map and offsets or sizes with nulls");
    }
    if (array_offset != 0) {
      return Status::Invalid(
          "List offsets and sizes must not be slices if a validity map is specified");
    }
  } else {
    if (offsets.null_count() > 0 && sizes.null_count() > 0) {
      return Status::Invalid("Ambiguous to specify both offsets and sizes with nulls");
    }
  }

  DCHECK(offsets.length() == sizes.length() || offsets.length() - 1 == sizes.length());

  using OffsetArrayType = typename TypeTraits<OffsetArrowType>::ArrayType;
  const auto& typed_offsets = checked_cast<const OffsetArrayType&>(offsets);
  const auto& typed_sizes = checked_cast<const OffsetArrayType&>(sizes);

  auto derived_validity_buffer = std::move(null_bitmap);
  if (offsets.null_count() > 0) {
    derived_validity_buffer = offsets.null_bitmap();
    null_count = offsets.null_count();
    // We allow construction from an offsets array containing one extra value.
    // If that is the case, we might need to discount one null from out_null_count.
    if (offsets.length() - 1 == sizes.length() && !offsets.IsValid(sizes.length())) {
      null_count -= 1;
    }
  } else if (sizes.null_count() > 0) {
    derived_validity_buffer = sizes.null_bitmap();
    null_count = sizes.null_count();