jorisvandenbossche commented on code in PR #34408: URL: https://github.com/apache/arrow/pull/34408#discussion_r1164143465
########## cpp/src/arrow/util/union_util.cc: ########## @@ -0,0 +1,58 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you 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. + +#include "arrow/util/union_util.h" + +#include <cstdint> + +#include "arrow/array/data.h" +#include "arrow/util/checked_cast.h" +#include "arrow/util/logging.h" + +namespace arrow::union_util { + +int64_t LogicalSparseUnionNullCount(const ArraySpan& span) { + const auto* sparse_union_type = + internal::checked_cast<const SparseUnionType*>(span.type); + DCHECK_LE(span.child_data.size(), 128); + + const int8_t* types = span.GetValues<int8_t>(1); // NOLINT + int64_t null_count = 0; + for (int64_t i = 0; i < span.length; i++) { + const int8_t child_id = sparse_union_type->child_ids()[types[span.offset + i]]; + + null_count += span.child_data[child_id].IsNull(i); Review Comment: Did you test this with a sliced array? (don't directly see it in the tests) Because in https://github.com/apache/arrow/pull/35036, I based my implementation on this function, and I am finding that I need to remove/add the offset like so: ```suggestion const int8_t child_id = sparse_union_type->child_ids()[types[i]]; null_count += span.child_data[child_id].IsNull(span.offset + i); ``` So `types`, which is the result of `Span.GetValues()` already takes into account the span's offset, but `IsNull()` is called on the child_data, and accessing child_data gives the original array data without offset already taken into account. -- 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: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
