1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.compress.utils;
18
19 import java.io.IOException;
20 import java.nio.ByteBuffer;
21 import java.nio.channels.SeekableByteChannel;
22
23 /**
24 * InputStream that delegates requests to the underlying SeekableByteChannel, making sure that only bytes from a certain range can be read.
25 *
26 * @ThreadSafe
27 * @since 1.21
28 */
29 public class BoundedSeekableByteChannelInputStream extends BoundedArchiveInputStream {
30
31 private final SeekableByteChannel channel;
32
33 /**
34 * Constructs a bounded stream on the underlying {@link SeekableByteChannel}
35 *
36 * @param start Position in the stream from where the reading of this bounded stream starts
37 * @param remaining Amount of bytes which are allowed to read from the bounded stream
38 * @param channel Channel which the reads will be delegated to
39 */
40 public BoundedSeekableByteChannelInputStream(final long start, final long remaining, final SeekableByteChannel channel) {
41 super(start, remaining);
42 this.channel = channel;
43 }
44
45 @Override
46 protected int read(final long pos, final ByteBuffer buf) throws IOException {
47 int read;
48 synchronized (channel) {
49 channel.position(pos);
50 read = channel.read(buf);
51 }
52 buf.flip();
53 return read;
54 }
55 }