    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 */
    019package org.apache.commons.compress.archivers.tar;
    020
    021import 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
    043public class TarArchiveSparseEntry implements TarConstants {
    044    /** If an extension sparse header follows. */
    045    private final 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(final 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}