    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 *   https://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.zip;
    020
    021import java.util.zip.ZipException;
    022
    023/**
    024 * X.509 Certificate ID and Signature for central directory (0x0016).
    025 *
    026 * <p>
    027 * This field contains the information about which certificate in the PKCS#7 store was used to sign the central directory structure. When the Central Directory
    028 * Encryption feature is enabled for a ZIP file, this record will appear in the Archive Extra Data Record, otherwise it will appear in the first central
    029 * directory record.
    030 * </p>
    031 *
    032 * <p>
    033 * Note: all fields stored in Intel low-byte/high-byte order.
    034 * </p>
    035 *
    036 * <pre>
    037 *         Value     Size     Description
    038 *         -----     ----     -----------
    039 * (CDID)  0x0016    2 bytes  Tag for this "extra" block type
    040 *         TSize     2 bytes  Size of data that follows
    041 *         RCount    4 bytes  Number of recipients. (inferred)
    042 *         HashAlg   2 bytes  Hash algorithm identifier. (inferred)
    043 *         TData     TSize    Data
    044 * </pre>
    045 *
    046 * @NotThreadSafe
    047 * @since 1.11
    048 */
    049public class X0016_CertificateIdForCentralDirectory extends PKWareExtraHeader {
    050
    051    static final ZipShort HEADER_ID = new ZipShort(0x0016);
    052
    053    private int rcount;
    054
    055    private HashAlgorithm hashAlg;
    056
    057    /**
    058     * Constructs a new instance.
    059     */
    060    public X0016_CertificateIdForCentralDirectory() {
    061        super(HEADER_ID);
    062    }
    063
    064    /**
    065     * Gets hash algorithm.
    066     *
    067     * @return the hash algorithm
    068     */
    069    public HashAlgorithm getHashAlgorithm() {
    070        return hashAlg;
    071    }
    072
    073    /**
    074     * Gets record count.
    075     *
    076     * @return the record count
    077     */
    078    public int getRecordCount() {
    079        return rcount;
    080    }
    081
    082    @Override
    083    public void parseFromCentralDirectoryData(final byte[] data, final int offset, final int length) throws ZipException {
    084        assertMinimalLength(4, length);
    085        // TODO: double check we really do not want to call super here
    086        this.rcount = ZipShort.getValue(data, offset);
    087        this.hashAlg = HashAlgorithm.getAlgorithmByCode(ZipShort.getValue(data, offset + 2));
    088    }
    089}