    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one
    003     * or more contributor license agreements.  See the NOTICE file
    004     * distributed with this work for additional information
    005     * regarding copyright ownership.  The ASF licenses this file
    006     * to you under the Apache License, Version 2.0 (the
    007     * "License"); you may not use this file except in compliance
    008     * with the License.  You may obtain a copy of the License at
    009     *
    010     * http://www.apache.org/licenses/LICENSE-2.0
    011     *
    012     * Unless required by applicable law or agreed to in writing,
    013     * software distributed under the License is distributed on an
    014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015     * KIND, either express or implied.  See the License for the
    016     * specific language governing permissions and limitations
    017     * under the License.
    018     */
    019    package org.apache.commons.compress.archivers.tar;
    020
    021    import java.io.IOException;
    022
    023    /**
    024     * This class represents a sparse entry in a Tar archive.
    025     *
    026     * <p>
    027     * The C structure for a sparse entry is:
    028     * <pre>
    029     * struct posix_header {
    030     * struct sparse sp[21]; // TarConstants.SPARSELEN_GNU_SPARSE     - offset 0
    031     * char isextended;      // TarConstants.ISEXTENDEDLEN_GNU_SPARSE - offset 504
    032     * };
    033     * </pre>
    034     * Whereas, "struct sparse" is:
    035     * <pre>
    036     * struct sparse {
    037     * char offset[12];   // offset 0
    038     * char numbytes[12]; // offset 12
    039     * };
    040     * </pre>
    041     */
    042
    043    public class TarArchiveSparseEntry implements TarConstants {
    044        /** If an extension sparse header follows. */
    045        private boolean isExtended;
    046
    047        /**
    048         * Construct an entry from an archive's header bytes. File is set
    049         * to null.
    050         *
    051         * @param headerBuf The header bytes from a tar archive entry.
    052         * @throws IOException on unknown format
    053         */
    054        public TarArchiveSparseEntry(byte[] headerBuf) throws IOException {
    055            int offset = 0;
    056            offset += SPARSELEN_GNU_SPARSE;
    057            isExtended = TarUtils.parseBoolean(headerBuf, offset);
    058        }
    059
    060        public boolean isExtended() {
    061            return isExtended;
    062        }
    063    }