src/main/java/org/apache/commons/compress/archivers/sevenz/BoundedRandomAccessFileInputStream.java

/*
 *  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.
 *
 */
package org.apache.commons.compress.archivers.sevenz;

import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;

class BoundedRandomAccessFileInputStream extends InputStream {
    private final RandomAccessFile file;
    private long bytesRemaining;

    public BoundedRandomAccessFileInputStream(final RandomAccessFile file,
            final long size) {
        this.file = file;
        this.bytesRemaining = size;
    }
    
    @Override
    public int read() throws IOException {
        if (bytesRemaining > 0) {
            --bytesRemaining;
            return file.read();
        }
        return -1;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        if (bytesRemaining == 0) {
            return -1;
        }
        int bytesToRead = len;
        if (bytesToRead > bytesRemaining) {
            bytesToRead = (int) bytesRemaining;
        }
        final int bytesRead = file.read(b, off, bytesToRead);
        if (bytesRead >= 0) {
            bytesRemaining -= bytesRead;
        }
        return bytesRead;
    }

    @Override
    public void close() {
        // the nested RandomAccessFile is controlled externally
    }
}