1 // Licensed to the Apache Software Foundation (ASF) under one or more
2 // contributor license agreements. See the NOTICE file distributed with
3 // this work for additional information regarding copyright ownership.
4 // The ASF licenses this file to You under the Apache License, Version 2.0
5 // (the "License"); you may not use this file except in compliance with
6 // the License.  You may obtain a copy of the License at
7 //
8 //     http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 
16 using Apache.Arrow.Memory;
17 using System.IO;
18 using System.Threading;
19 using System.Threading.Tasks;
20 
21 namespace Apache.Arrow.Ipc
22 {
23     /// <summary>
24     /// Implements an <see cref="ArrowStreamReader"/> that can read Arrow files.
25     /// </summary>
26     public class ArrowFileReader : ArrowStreamReader
27     {
28         private ArrowFileReaderImplementation Implementation =>
29             (ArrowFileReaderImplementation)_implementation;
30 
31         public bool IsFileValid => Implementation.IsFileValid;
32 
ArrowFileReader(Stream stream)33         public ArrowFileReader(Stream stream)
34             : this(stream, leaveOpen: false)
35         {
36         }
37 
ArrowFileReader(Stream stream, MemoryAllocator allocator)38         public ArrowFileReader(Stream stream, MemoryAllocator allocator)
39             : this(stream, allocator, leaveOpen: false)
40         {
41         }
42 
ArrowFileReader(Stream stream, bool leaveOpen)43         public ArrowFileReader(Stream stream, bool leaveOpen)
44             : this(stream, allocator: null, leaveOpen)
45         {
46         }
47 
ArrowFileReader(Stream stream, MemoryAllocator allocator, bool leaveOpen)48         public ArrowFileReader(Stream stream, MemoryAllocator allocator, bool leaveOpen)
49             : base(new ArrowFileReaderImplementation(stream, allocator, leaveOpen))
50         {
51         }
52 
FromFile(string filename)53         public static ArrowFileReader FromFile(string filename)
54         {
55             var stream = new FileStream(filename, FileMode.Open, FileAccess.Read);
56             return new ArrowFileReader(stream);
57         }
58 
RecordBatchCountAsync()59         public ValueTask<int> RecordBatchCountAsync()
60         {
61             return Implementation.RecordBatchCountAsync();
62         }
63 
ReadRecordBatchAsync(int index, CancellationToken cancellationToken = default)64         public ValueTask<RecordBatch> ReadRecordBatchAsync(int index, CancellationToken cancellationToken = default)
65         {
66             return Implementation.ReadRecordBatchAsync(index, cancellationToken);
67         }
68     }
69 }
70