org.apache.commons.compress.archivers.tar.TarArchiveSparseEntry Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of commons-compress Show documentation

Apache Commons Compress defines an API for working with compression and archive formats. These include bzip2, gzip, pack200, LZMA, XZ, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.

There is a newer version: 1.27.1

Show newest version

/*
 * 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.tar;

import java.io.IOException;

/**
 * This class represents a sparse entry in a Tar archive.
 *
 * 
 * The C structure for a sparse entry is:
 * 
 * struct posix_header {
 * struct sparse sp[21]; // TarConstants.SPARSELEN_GNU_SPARSE     - offset 0
 * char isextended;      // TarConstants.ISEXTENDEDLEN_GNU_SPARSE - offset 504
 * };
 * 
 * Whereas, "struct sparse" is:
 *  * struct sparse {
 * char offset[12];   // offset 0
 * char numbytes[12]; // offset 12
 * };
 * 
 */

public class TarArchiveSparseEntry implements TarConstants {
    /** If an extension sparse header follows. */
    private final boolean isExtended;

    /**
     * Construct an entry from an archive's header bytes. File is set
     * to null.
     *
     * @param headerBuf The header bytes from a tar archive entry.
     * @throws IOException on unknown format
     */
    public TarArchiveSparseEntry(byte[] headerBuf) throws IOException {
        int offset = 0;
        offset += SPARSELEN_GNU_SPARSE;
        isExtended = TarUtils.parseBoolean(headerBuf, offset);
    }

    public boolean isExtended() {
        return isExtended;
    }
}