001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.commons.compress.utils; 019 020import java.io.IOException; 021import java.nio.ByteBuffer; 022import java.nio.channels.SeekableByteChannel; 023 024/** 025 * InputStream that delegates requests to the underlying SeekableByteChannel, making sure that only bytes from a certain 026 * range can be read. 027 * @ThreadSafe 028 * @since 1.21 029 */ 030public class BoundedSeekableByteChannelInputStream extends BoundedArchiveInputStream { 031 032 private final SeekableByteChannel channel; 033 034 /** 035 * Create a bounded stream on the underlying {@link SeekableByteChannel} 036 * 037 * @param start Position in the stream from where the reading of this bounded stream starts 038 * @param remaining Amount of bytes which are allowed to read from the bounded stream 039 * @param channel Channel which the reads will be delegated to 040 */ 041 public BoundedSeekableByteChannelInputStream(final long start, final long remaining, 042 final SeekableByteChannel channel) { 043 super(start, remaining); 044 this.channel = channel; 045 } 046 047 @Override 048 protected int read(long pos, ByteBuffer buf) throws IOException { 049 int read; 050 synchronized (channel) { 051 channel.position(pos); 052 read = channel.read(buf); 053 } 054 buf.flip(); 055 return read; 056 } 057}