felipecrv commented on code in PR #35345:
URL: https://github.com/apache/arrow/pull/35345#discussion_r1319886685
##########
cpp/src/arrow/array/array_nested.cc:
##########
@@ -189,11 +261,109 @@ Result<std::shared_ptr<Array>> FlattenListArray(const
ListArrayT& list_array,
return Concatenate(non_null_fragments, memory_pool);
}
+template <typename ListViewArrayT>
+Result<std::shared_ptr<Array>> FlattenListViewArray(const ListViewArrayT&
list_view_array,
+ MemoryPool* memory_pool) {
+ using offset_type = typename ListViewArrayT::offset_type;
+ const int64_t list_view_array_length = list_view_array.length();
+ std::shared_ptr<arrow::Array> value_array = list_view_array.values();
+
+ if (list_view_array_length == 0) {
+ return SliceArrayWithOffsets(*value_array, 0, 0);
+ }
+
+ // If the list array is *all* nulls, then just return an empty array.
+ if (list_view_array.null_count() == list_view_array.length()) {
+ return MakeEmptyArray(value_array->type(), memory_pool);
+ }
+
+ const auto* validity = list_view_array.data()->template
GetValues<uint8_t>(0);
+ const auto* offsets = list_view_array.data()->template
GetValues<offset_type>(1);
+ const auto* sizes = list_view_array.data()->template
GetValues<offset_type>(2);
+
+ // If a ListViewArray:
+ //
+ // 1) does not contain nulls
+ // 2) has sorted offsets
+ // 3) every view is disjoint
+ //
+ // then simply slice its value array with the first offset and end of the
last list
+ // view.
+ if (list_view_array.null_count() == 0) {
+ bool sorted_and_disjoint = true;
+ for (int64_t i = 1; sorted_and_disjoint && i < list_view_array_length;
++i) {
+ sorted_and_disjoint &=
+ sizes[i - 1] == 0 || offsets[i] - offsets[i - 1] == sizes[i - 1];
+ }
+
+ if (sorted_and_disjoint) {
+ const auto begin_offset = list_view_array.value_offset(0);
+ const auto end_offset =
list_view_array.value_offset(list_view_array_length - 1) +
+
list_view_array.value_length(list_view_array_length - 1);
+ return SliceArrayWithOffsets(*value_array, begin_offset, end_offset);
+ }
+ }
+
+ std::vector<std::shared_ptr<Array>> non_null_fragments;
+ // Index of first valid list-view and last offset
+ // of the current contiguous fragment in values.
+ int64_t first_i = -1;
+ offset_type end_offset = -1;
+ int64_t i = 0;
+ for (; i < list_view_array_length; i++) {
+ if ((validity && !bit_util::GetBit(validity, i)) || sizes[i] == 0) {
+ continue;
+ }
+ first_i = i;
+ end_offset = offsets[i] + sizes[i];
+ break;
+ }
+ i += 1;
+ for (; i < list_view_array_length; i++) {
Review Comment:
I can extract a few more functions. Just a minute.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
