    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     * The Header-ID.
    036     *
    037     * @return The HeaderId value
    038     */
    039    ZipShort getHeaderId();
    040
    041    /**
    042     * Length of the extra field in the local file data - without
    043     * Header-ID or length specifier.
    044     * @return the length of the field in the local file data
    045     */
    046    ZipShort getLocalFileDataLength();
    047
    048    /**
    049     * Length of the extra field in the central directory - without
    050     * Header-ID or length specifier.
    051     * @return the length of the field in the central directory
    052     */
    053    ZipShort getCentralDirectoryLength();
    054
    055    /**
    056     * The actual data to put into local file data - without Header-ID
    057     * or length specifier.
    058     * @return the data
    059     */
    060    byte[] getLocalFileDataData();
    061
    062    /**
    063     * The actual data to put into central directory - without Header-ID or
    064     * length specifier.
    065     * @return the data
    066     */
    067    byte[] getCentralDirectoryData();
    068
    069    /**
    070     * Populate data from this array as if it was in local file data.
    071     *
    072     * @param buffer the buffer to read data from
    073     * @param offset offset into buffer to read data
    074     * @param length the length of data
    075     * @throws ZipException on error
    076     */
    077    void parseFromLocalFileData(byte[] buffer, int offset, int length)
    078        throws ZipException;
    079
    080    /**
    081     * Populate data from this array as if it was in central directory data.
    082     *
    083     * @param buffer the buffer to read data from
    084     * @param offset offset into buffer to read data
    085     * @param length the length of data
    086     * @throws ZipException on error
    087     */
    088    void parseFromCentralDirectoryData(byte[] buffer, int offset, int length)
    089        throws ZipException;
    090}