arrow/util/list_util.h

0001 // Licensed to the Apache Software Foundation (ASF) under one
0002 // or more contributor license agreements.  See the NOTICE file
0003 // distributed with this work for additional information
0004 // regarding copyright ownership.  The ASF licenses this file
0005 // to you under the Apache License, Version 2.0 (the
0006 // "License"); you may not use this file except in compliance
0007 // with the License.  You may obtain a copy of the License at
0008 //
0009 //   http://www.apache.org/licenses/LICENSE-2.0
0010 //
0011 // Unless required by applicable law or agreed to in writing,
0012 // software distributed under the License is distributed on an
0013 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
0014 // KIND, either express or implied.  See the License for the
0015 // specific language governing permissions and limitations
0016 // under the License.
0017
0018 #pragma once
0019
0020 #include <cstdint>
0021 #include <utility>
0022
0023 #include "arrow/array/data.h"
0024 #include "arrow/result.h"
0025
0026 namespace arrow {
0027 namespace list_util {
0028 namespace internal {
0029
0030 /// \brief Calculate the smallest continuous range of values used by the
0031 /// var-length list-like input (list, map and list-view types).
0032 ///
0033 /// \param input The input array such that is_var_length_list_like(input.type)
0034 /// is true
0035 /// \return A pair of (offset, length) describing the range
0036 ARROW_EXPORT Result<std::pair<int64_t, int64_t>> RangeOfValuesUsed(
0037     const ArraySpan& input);
0038
0039 /// \brief Calculate the sum of the sizes of all valid lists or list-views
0040 ///
0041 /// This is usually the same as the length of the RangeOfValuesUsed() range, but
0042 /// it can be:
0043 /// - Smaller: when the child array contains many values that are not
0044 /// referenced by the lists or list-views in the parent array
0045 /// - Greater: when the list-views share child array ranges
0046 ///
0047 /// \param input The input array such that is_var_length_list_like(input.type)
0048 /// is true
0049 /// \return The sum of all list or list-view sizes
0050 ARROW_EXPORT Result<int64_t> SumOfLogicalListSizes(const ArraySpan& input);
0051
0052 }  // namespace internal
0053
0054 }  // namespace list_util
0055 }  // namespace arrow