    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.zip;
    020
    021import java.util.zip.ZipException;
    022
    023/**
    024 * General format of extra field data.
    025 *
    026 * <p>Extra fields usually appear twice per file, once in the local
    027 * file data and once in the central directory.  Usually they are the
    028 * same, but they don't have to be.  {@link
    029 * java.util.zip.ZipOutputStream java.util.zip.ZipOutputStream} will
    030 * only use the local file data in both places.</p>
    031 *
    032 */
    033public interface ZipExtraField {
    034    /**
    035     * Size of an extra field header (id + length).
    036     * @since 1.14
    037     */
    038    int EXTRAFIELD_HEADER_SIZE = 4;
    039
    040    /**
    041     * The actual data to put into central directory - without Header-ID or
    042     * length specifier.
    043     * @return the data
    044     */
    045    byte[] getCentralDirectoryData();
    046
    047    /**
    048     * Length of the extra field in the central directory - without
    049     * Header-ID or length specifier.
    050     * @return the length of the field in the central directory
    051     */
    052    ZipShort getCentralDirectoryLength();
    053
    054    /**
    055     * The Header-ID.
    056     *
    057     * @return The HeaderId value
    058     */
    059    ZipShort getHeaderId();
    060
    061    /**
    062     * The actual data to put into local file data - without Header-ID
    063     * or length specifier.
    064     * @return the data
    065     */
    066    byte[] getLocalFileDataData();
    067
    068    /**
    069     * Length of the extra field in the local file data - without
    070     * Header-ID or length specifier.
    071     * @return the length of the field in the local file data
    072     */
    073    ZipShort getLocalFileDataLength();
    074
    075    /**
    076     * Populate data from this array as if it was in central directory data.
    077     *
    078     * @param buffer the buffer to read data from
    079     * @param offset offset into buffer to read data
    080     * @param length the length of data
    081     * @throws ZipException on error
    082     */
    083    void parseFromCentralDirectoryData(byte[] buffer, int offset, int length)
    084        throws ZipException;
    085
    086    /**
    087     * Populate data from this array as if it was in local file data.
    088     *
    089     * @param buffer the buffer to read data from
    090     * @param offset offset into buffer to read data
    091     * @param length the length of data
    092     * @throws ZipException on error
    093     */
    094    void parseFromLocalFileData(byte[] buffer, int offset, int length)
    095        throws ZipException;
    096}