westonpace commented on code in PR #37885: URL: https://github.com/apache/arrow/pull/37885#discussion_r1338664548
########## csharp/src/Apache.Arrow/Types/MapType.cs: ########## @@ -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. + +using System.Collections.Generic; + +namespace Apache.Arrow.Types +{ + public sealed class MapType : NestedType // MapType = ListType(StrucType("key", "value")) Review Comment: ```suggestion public sealed class MapType : NestedType // MapType = ListType(StructType("key", "value")) ``` ########## csharp/src/Apache.Arrow/Arrays/MapArray.cs: ########## @@ -0,0 +1,174 @@ +// 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; +using Apache.Arrow.Types; + +namespace Apache.Arrow +{ + public class MapArray : ListArray // MapArray = ListArray(StrucArray("key", "value")) Review Comment: ```suggestion public class MapArray : ListArray // MapArray = ListArray(StructArray("key", "value")) ``` ########## csharp/src/Apache.Arrow/Arrays/ArrayDataConcatenator.cs: ########## @@ -151,6 +145,8 @@ public void Visit(UnionType type) Result = new ArrayData(type, _totalLength, _totalNullCount, 0, buffers, children); } + public void Visit(MapType type) => ConcatenateLists(type.UnsortedKey()); Review Comment: Technically I suppose there is a possibility the output map is still sorted (e.g. all the keys in the left map are less than the keys in the right map) but I agree this is the right call. I don't know that there is any good spot to document this very minor note though. ########## csharp/src/Apache.Arrow/Arrays/MapArray.cs: ########## @@ -0,0 +1,174 @@ +// 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; +using Apache.Arrow.Types; + +namespace Apache.Arrow +{ + public class MapArray : ListArray // MapArray = ListArray(StrucArray("key", "value")) + { + // Same as ListArray.Builder, but with KeyBuilder + public new class Builder : IArrowArrayBuilder<MapArray, Builder> + { + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> KeyBuilder { get; } + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> ValueBuilder { get; } + + public int Length => ValueOffsetsBufferBuilder.Length; + + private ArrowBuffer.Builder<int> ValueOffsetsBufferBuilder { get; } + + private ArrowBuffer.BitmapBuilder ValidityBufferBuilder { get; } + + public int NullCount { get; protected set; } + + public MapType DataType { get; } + + public Builder(MapType type) + { + KeyBuilder = ArrowArrayBuilderFactory.Build(type.KeyField.DataType); + ValueBuilder = ArrowArrayBuilderFactory.Build(type.ValueField.DataType); + ValueOffsetsBufferBuilder = new ArrowBuffer.Builder<int>(); + ValidityBufferBuilder = new ArrowBuffer.BitmapBuilder(); + DataType = type; + } + + /// <summary> + /// Start a new variable-length list slot + /// + /// This function should be called before beginning to append elements to the + /// value builder + /// </summary> + /// <returns></returns> + public Builder Append() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(true); + + return this; + } + + public Builder AppendNull() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(false); + NullCount++; + + return this; + } + + public MapArray Build(MemoryAllocator allocator = default) + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + + ArrowBuffer validityBuffer = NullCount > 0 ? ValidityBufferBuilder.Build(allocator) : ArrowBuffer.Empty; + + StructArray structs = new StructArray( + DataType.KeyValueType, KeyBuilder.Length, + new IArrowArray[] { KeyBuilder.Build(allocator), ValueBuilder.Build(allocator) }, + ArrowBuffer.Empty, 0 + ); + + return new MapArray(DataType, Length - 1, ValueOffsetsBufferBuilder.Build(allocator), structs, validityBuffer, NullCount); + } + + public Builder Reserve(int capacity) + { + ValueOffsetsBufferBuilder.Reserve(capacity + 1); + ValidityBufferBuilder.Reserve(capacity + 1); + return this; + } + + public Builder Resize(int length) + { + ValueOffsetsBufferBuilder.Resize(length + 1); + ValidityBufferBuilder.Resize(length + 1); Review Comment: Same question, why +1 for validity buffer here? ########## csharp/src/Apache.Arrow/Arrays/MapArray.cs: ########## @@ -0,0 +1,174 @@ +// 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; +using Apache.Arrow.Types; + +namespace Apache.Arrow +{ + public class MapArray : ListArray // MapArray = ListArray(StrucArray("key", "value")) + { + // Same as ListArray.Builder, but with KeyBuilder + public new class Builder : IArrowArrayBuilder<MapArray, Builder> + { + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> KeyBuilder { get; } + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> ValueBuilder { get; } + + public int Length => ValueOffsetsBufferBuilder.Length; + + private ArrowBuffer.Builder<int> ValueOffsetsBufferBuilder { get; } + + private ArrowBuffer.BitmapBuilder ValidityBufferBuilder { get; } + + public int NullCount { get; protected set; } + + public MapType DataType { get; } + + public Builder(MapType type) + { + KeyBuilder = ArrowArrayBuilderFactory.Build(type.KeyField.DataType); + ValueBuilder = ArrowArrayBuilderFactory.Build(type.ValueField.DataType); + ValueOffsetsBufferBuilder = new ArrowBuffer.Builder<int>(); + ValidityBufferBuilder = new ArrowBuffer.BitmapBuilder(); + DataType = type; + } + + /// <summary> + /// Start a new variable-length list slot + /// + /// This function should be called before beginning to append elements to the + /// value builder + /// </summary> + /// <returns></returns> + public Builder Append() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(true); + + return this; + } + + public Builder AppendNull() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(false); + NullCount++; + + return this; + } + + public MapArray Build(MemoryAllocator allocator = default) + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + + ArrowBuffer validityBuffer = NullCount > 0 ? ValidityBufferBuilder.Build(allocator) : ArrowBuffer.Empty; + + StructArray structs = new StructArray( + DataType.KeyValueType, KeyBuilder.Length, + new IArrowArray[] { KeyBuilder.Build(allocator), ValueBuilder.Build(allocator) }, + ArrowBuffer.Empty, 0 + ); + + return new MapArray(DataType, Length - 1, ValueOffsetsBufferBuilder.Build(allocator), structs, validityBuffer, NullCount); + } + + public Builder Reserve(int capacity) + { + ValueOffsetsBufferBuilder.Reserve(capacity + 1); + ValidityBufferBuilder.Reserve(capacity + 1); + return this; + } + + public Builder Resize(int length) + { + ValueOffsetsBufferBuilder.Resize(length + 1); + ValidityBufferBuilder.Resize(length + 1); + return this; + } + + public Builder Clear() + { + ValueOffsetsBufferBuilder.Clear(); + KeyBuilder.Clear(); + ValueBuilder.Clear(); + ValidityBufferBuilder.Clear(); + return this; + } + + } + + public StructArray KeyValues => base.Values as StructArray; + public IArrowArray Keys => KeyValues.Fields[0]; + public new IArrowArray Values => KeyValues.Fields[1]; + + public MapArray(IArrowType dataType, int length, + ArrowBuffer valueOffsetsBuffer, IArrowArray structs, + ArrowBuffer nullBitmapBuffer, int nullCount = 0, int offset = 0) + : this( + new ArrayData( + dataType, length, nullCount, offset, new[] { nullBitmapBuffer, valueOffsetsBuffer }, + new[] { structs.Data } + ), structs) + { + } + + public MapArray(ArrayData data) + : this(data, ArrowArrayFactory.BuildArray(data.Children[0])) + { + } + + private MapArray(ArrayData data, IArrowArray structs) : base(data, structs, ArrowTypeId.Map) + { + } + + public IEnumerable<Tuple<K, V>> GetTuples<TKeyArray, K, TValueArray, V>(int index, Func<TKeyArray, int, K> getKey, Func<TValueArray, int, V> getValue) + where TKeyArray : Array where TValueArray : Array + { + ReadOnlySpan<int> offsets = ValueOffsets; + // Get key values + int start = offsets[index]; + int end = offsets[index + 1]; + StructArray array = KeyValues.Slice(start, end - start) as StructArray; + + TKeyArray keyArray = array.Fields[0] as TKeyArray; + TValueArray valueArray = array.Fields[1] as TValueArray; + + for (int i = start; i < end; i++) + { + yield return new Tuple<K, V>(getKey(keyArray, i), getValue(valueArray, i)); + } + } + + public IEnumerable<KeyValuePair<K,V>> GetKeyValuePairs<TKeyArray, K, TValueArray, V>(int index, Func<TKeyArray, int, K> getKey, Func<TValueArray, int, V> getValue) + where TKeyArray : Array where TValueArray : Array + { + ReadOnlySpan<int> offsets = ValueOffsets; + // Get key values + int start = offsets[index]; + int end = offsets[index + 1]; + StructArray array = KeyValues.Slice(start, end - start) as StructArray; + + TKeyArray keyArray = array.Fields[0] as TKeyArray; + TValueArray valueArray = array.Fields[1] as TValueArray; + + for (int i = start; i < end; i++) + { + yield return new KeyValuePair<K,V>(getKey(keyArray, i), getValue(valueArray, i)); + } + } Review Comment: These APIs are a little more complex than others (due to the need for `getKey` and `getValue`. It shouldn't be done as part of this PR but I wonder if we might want to start working on "examples" or a "cookbook" for C# at some point. Accessing map values would be a good example. ########## csharp/src/Apache.Arrow/Arrays/ArrayDataConcatenator.cs: ########## @@ -114,14 +107,15 @@ public void Visit(FixedSizeListType type) public void Visit(StructType type) { CheckData(type, 1); + ArrowBuffer validityBuffer = ConcatenateValidityBuffer(); Review Comment: Good catch. For regression purposes, can you add a test case that would have caught this? ########## csharp/src/Apache.Arrow/Arrays/MapArray.cs: ########## @@ -0,0 +1,174 @@ +// 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; +using Apache.Arrow.Types; + +namespace Apache.Arrow +{ + public class MapArray : ListArray // MapArray = ListArray(StrucArray("key", "value")) + { + // Same as ListArray.Builder, but with KeyBuilder + public new class Builder : IArrowArrayBuilder<MapArray, Builder> + { + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> KeyBuilder { get; } + public IArrowArrayBuilder<IArrowArray, IArrowArrayBuilder<IArrowArray>> ValueBuilder { get; } + + public int Length => ValueOffsetsBufferBuilder.Length; + + private ArrowBuffer.Builder<int> ValueOffsetsBufferBuilder { get; } + + private ArrowBuffer.BitmapBuilder ValidityBufferBuilder { get; } + + public int NullCount { get; protected set; } + + public MapType DataType { get; } + + public Builder(MapType type) + { + KeyBuilder = ArrowArrayBuilderFactory.Build(type.KeyField.DataType); + ValueBuilder = ArrowArrayBuilderFactory.Build(type.ValueField.DataType); + ValueOffsetsBufferBuilder = new ArrowBuffer.Builder<int>(); + ValidityBufferBuilder = new ArrowBuffer.BitmapBuilder(); + DataType = type; + } + + /// <summary> + /// Start a new variable-length list slot + /// + /// This function should be called before beginning to append elements to the + /// value builder + /// </summary> + /// <returns></returns> + public Builder Append() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(true); + + return this; + } + + public Builder AppendNull() + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + ValidityBufferBuilder.Append(false); + NullCount++; + + return this; + } + + public MapArray Build(MemoryAllocator allocator = default) + { + ValueOffsetsBufferBuilder.Append(KeyBuilder.Length); + + ArrowBuffer validityBuffer = NullCount > 0 ? ValidityBufferBuilder.Build(allocator) : ArrowBuffer.Empty; + + StructArray structs = new StructArray( + DataType.KeyValueType, KeyBuilder.Length, + new IArrowArray[] { KeyBuilder.Build(allocator), ValueBuilder.Build(allocator) }, + ArrowBuffer.Empty, 0 + ); + + return new MapArray(DataType, Length - 1, ValueOffsetsBufferBuilder.Build(allocator), structs, validityBuffer, NullCount); + } + + public Builder Reserve(int capacity) + { + ValueOffsetsBufferBuilder.Reserve(capacity + 1); + ValidityBufferBuilder.Reserve(capacity + 1); Review Comment: Why +1 for the validity buffer? -- 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]
