/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
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 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.zip;

import java.util.zip.ZipException;

/**
 * General format of extra field data.
 *
 * <p>Extra fields usually appear twice per file, once in the local
 * file data and once in the central directory.  Usually they are the
 * same, but they don't have to be.  {@link
 * java.util.zip.ZipOutputStream java.util.zip.ZipOutputStream} will
 * only use the local file data in both places.</p>
 *
 * @author <a href="stefan.bodewig@epost.de">Stefan Bodewig</a>
 * @version $Revision: 1.2 $
 */
public interface ZipExtraField {

    /**
     * The Header-ID.
     *
     * @since 1.1
     */
    public ZipShort getHeaderId();

    /**
     * Length of the extra field in the local file data - without
     * Header-ID or length specifier.
     *
     * @since 1.1
     */
    public ZipShort getLocalFileDataLength();

    /**
     * Length of the extra field in the central directory - without
     * Header-ID or length specifier.
     *
     * @since 1.1
     */
    public ZipShort getCentralDirectoryLength();

    /**
     * The actual data to put into local file data - without Header-ID
     * or length specifier.
     *
     * @since 1.1
     */
    public byte[] getLocalFileDataData();

    /**
     * The actual data to put central directory - without Header-ID or
     * length specifier.
     *
     * @since 1.1
     */
    public byte[] getCentralDirectoryData();

    /**
     * Populate data from this array as if it was in local file data.
     *
     * @since 1.1
     */
    public void parseFromLocalFileData(byte[] data, int offset, int length)
        throws ZipException;
}