import quincy 17.2.0

[ceph.git] / ceph / src / arrow / csharp / src / Apache.Arrow / Table.cs

diff --git a/ceph/src/arrow/csharp/src/Apache.Arrow/Table.cs b/ceph/src/arrow/csharp/src/Apache.Arrow/Table.cs
new file mode 100644 (file)
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+++ b/ceph/src/arrow/csharp/src/Apache.Arrow/Table.cs
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+// 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;
+
+namespace Apache.Arrow
+{
+    /// <summary>
+    /// A logical Table class to represent a dataset as a sequence of Columns
+    /// </summary>
+    public class Table
+    {
+        public Schema Schema { get; }
+        public long RowCount { get; }
+        public int ColumnCount { get; private set; }
+        public Column Column(int columnIndex) => _columns[columnIndex];
+
+        private readonly IList<Column> _columns;
+        public static Table TableFromRecordBatches(Schema schema, IList<RecordBatch> recordBatches)
+        {
+            int nBatches = recordBatches.Count;
+            int nColumns = schema.Fields.Count;
+
+            List<Column> columns = new List<Column>(nColumns);
+            List<Array> columnArrays = new List<Array>(nBatches);
+            for (int icol = 0; icol < nColumns; icol++)
+            {
+                for (int jj = 0; jj < nBatches; jj++)
+                {
+                    columnArrays.Add(recordBatches[jj].Column(icol) as Array);
+                }
+                columns.Add(new Arrow.Column(schema.GetFieldByIndex(icol), columnArrays));
+                columnArrays.Clear();
+            }
+
+            return new Table(schema, columns);
+        }
+
+        public Table(Schema schema, IList<Column> columns)
+        {
+            Schema = schema;
+            _columns = columns;
+            if (columns.Count > 0)
+            {
+                RowCount = columns[0].Length;
+                ColumnCount = columns.Count;
+            }
+        }
+
+        public Table()
+        {
+            Schema = new Schema.Builder().Build();
+            _columns = new List<Column>();
+        }
+
+        public Table RemoveColumn(int columnIndex)
+        {
+            Schema newSchema = Schema.RemoveField(columnIndex);
+            IList<Column> newColumns = Utility.DeleteListElement(_columns, columnIndex);
+            return new Table(newSchema, newColumns);
+        }
+
+        public Table InsertColumn(int columnIndex, Column column)
+        {
+            column = column ?? throw new ArgumentNullException(nameof(column));
+            if (columnIndex < 0 || columnIndex > _columns.Count)
+            {
+                throw new ArgumentException($"Invalid columnIndex {columnIndex} passed into Table.AddColumn");
+            }
+            if (column.Length != RowCount)
+            {
+                throw new ArgumentException($"Column's length {column.Length} must match Table's length {RowCount}");
+            }
+
+            Schema newSchema = Schema.InsertField(columnIndex, column.Field);
+            IList<Column> newColumns = Utility.AddListElement(_columns, columnIndex, column);
+            return new Table(newSchema, newColumns);
+        }
+
+        public Table SetColumn(int columnIndex, Column column)
+        {
+            column = column ?? throw new ArgumentNullException(nameof(column));
+            if (columnIndex < 0 || columnIndex >= ColumnCount)
+            {
+                throw new ArgumentException($"Invalid columnIndex {columnIndex} passed in to Table.SetColumn");
+            }
+
+            if (column.Length != RowCount)
+            {
+                throw new ArgumentException($"Column's length {column.Length} must match table's length {RowCount}");
+            }
+
+            Schema newSchema = Schema.SetField(columnIndex, column.Field);
+            IList<Column> newColumns = Utility.SetListElement(_columns, columnIndex, column);
+            return new Table(newSchema, newColumns);
+        }
+
+        // TODO: Flatten for Tables with Lists/Structs?
+    }
+}