TarArchiveSparseZeroInputStream.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
 *
 *   https://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.tar;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

import org.apache.commons.io.IOUtils;

/**
 * This is an InputStream that always return 0, this is used when reading the "holes" of a sparse file
 */
final class TarArchiveSparseZeroInputStream extends InputStream {

    /**
     * Returns 0.
     *
     * @return Always 0.
     */
    @Override
    public int read() {
        return 0;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        IOUtils.checkFromIndexSize(b, off, len);
        if (len == 0) {
            return 0;
        }
        Arrays.fill(b, off, off + len, (byte) 0);
        return len;
    }

    /**
     * Returns the input.
     *
     * @param n a value to return.
     * @return the input.
     */
    @Override
    public long skip(final long n) {
        return n;
    }
}