Abhilash437 commented on code in PR #408: URL: https://github.com/apache/arrow-dotnet/pull/408#discussion_r3776767590
########## src/Apache.Arrow/Arrays/RunEndEncodedArray.Builder.cs: ########## @@ -0,0 +1,400 @@ +// 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. + +using System; +using System.Collections.Generic; +using Apache.Arrow.Memory; + +namespace Apache.Arrow; + +public partial class RunEndEncodedArray +{ + /// <summary> + /// Builder for <see cref="RunEndEncodedArray"/>. + /// </summary> + /// <typeparam name="TRunEndBuilder">The type of the run ends array builder.</typeparam> + /// <typeparam name="TValueBuilder">The type of the values array builder.</typeparam> + /// <typeparam name="TRunEndArray">The type of the run ends array (must be Int16Array, Int32Array, or Int64Array).</typeparam> + /// <typeparam name="TValueArray">The type of the values array.</typeparam> + /// <typeparam name="TValue">The type of values contained in the values array.</typeparam> + public class Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> + : IArrowArrayBuilder<TValue, RunEndEncodedArray, Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue>> + where TRunEndBuilder : IArrowArrayBuilder<TRunEndArray> + where TValueBuilder : IArrowArrayBuilder<TValueArray> + where TRunEndArray : IArrowArray + where TValueArray : IArrowArray + { + private readonly IEqualityComparer<TValue> _comparer; + private int _currentRunLength; + private TValue _lastValue; + private bool _lastValueIsNull; + private bool _hasValue; + + /// <summary> + /// Gets the run ends builder. + /// </summary> + public TRunEndBuilder RunEndsBuilder { get; } + + /// <summary> + /// Gets the values builder. + /// </summary> + public TValueBuilder ValuesBuilder { get; } + + /// <summary> + /// Gets the total logical length of elements appended to this builder. + /// </summary> + public int Length => _currentRunLength; + + /// <summary> + /// Initializes a new instance of the <see cref="Builder{TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue}"/> class. + /// </summary> + /// <param name="runEndsBuilder">The builder to use for run-ends.</param> + /// <param name="valuesBuilder">The builder to use for values.</param> + /// <param name="comparer">Optional equality comparer for value run-length grouping.</param> + public Builder(TRunEndBuilder runEndsBuilder, TValueBuilder valuesBuilder, IEqualityComparer<TValue> comparer = null) + { + RunEndsBuilder = runEndsBuilder ?? throw new ArgumentNullException(nameof(runEndsBuilder)); + ValuesBuilder = valuesBuilder ?? throw new ArgumentNullException(nameof(valuesBuilder)); + _comparer = comparer ?? EqualityComparer<TValue>.Default; + } + + /// <summary> + /// Appends a single value to the builder, automatically grouping identical consecutive values into runs. + /// </summary> + /// <param name="value">The value to append.</param> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> Append(TValue value) + { + if (value is null) + { + return AppendNull(); + } + + if (_hasValue) + { + if (!_lastValueIsNull && _comparer.Equals(value, _lastValue)) + { + _currentRunLength++; + } + else + { + FlushCurrentRun(); + StartNewRun(value, isNull: false); + } + } + else + { + StartNewRun(value, isNull: false); + } + + return this; + } + + /// <summary> + /// Appends a null value to the builder. + /// </summary> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> AppendNull() + { + if (_hasValue) + { + if (_lastValueIsNull) + { + _currentRunLength++; + } + else + { + FlushCurrentRun(); + StartNewRun(default, isNull: true); + } + } + else + { + StartNewRun(default, isNull: true); + } + + return this; + } + + /// <summary> + /// Appends a span of values to the builder. + /// </summary> + /// <param name="span">The span of values to append.</param> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> Append(ReadOnlySpan<TValue> span) + { + foreach (TValue value in span) + { + Append(value); + } + return this; + } + + /// <summary> + /// Appends a sequence of values to the builder. + /// </summary> + /// <param name="values">The sequence of values to append.</param> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> AppendRange(IEnumerable<TValue> values) + { + if (values == null) + { + throw new ArgumentNullException(nameof(values)); + } + + foreach (TValue value in values) + { + Append(value); + } + return this; + } + + /// <summary> + /// Reserves capacity in the inner builders. + /// </summary> + /// <param name="capacity">The capacity to reserve.</param> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> Reserve(int capacity) + { + return this; + } + + /// <summary> + /// Resizes the builder. + /// </summary> + /// <param name="length">The target length.</param> + /// <returns>The builder instance for method chaining.</returns> + public Builder<TRunEndBuilder, TValueBuilder, TRunEndArray, TValueArray, TValue> Resize(int length) + { + return this; + } Review Comment: Updated `Resize(length)` to throw a `NotSupportedException("Resize is not supported on RunEndEncodedArray.Builder.")` to align with the behavior of `Set` and `Swap` on REE builders. -- This is an automated message from the Apache Git Service. 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