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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   * http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.commons.compress.archivers.zip;
20  
21  import java.util.zip.ZipException;
22  
23  /**
24   * General format of extra field data.
25   *
26   * <p>
27   * 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
28   * be. {@link java.util.zip.ZipOutputStream java.util.zip.ZipOutputStream} will only use the local file data in both places.
29   * </p>
30   */
31  public interface ZipExtraField {
32      /**
33       * Size of an extra field header (id + length).
34       *
35       * @since 1.14
36       */
37      int EXTRAFIELD_HEADER_SIZE = 4;
38  
39      /**
40       * The actual data to put into central directory - without Header-ID or length specifier.
41       *
42       * @return the data
43       */
44      byte[] getCentralDirectoryData();
45  
46      /**
47       * Length of the extra field in the central directory - without Header-ID or length specifier.
48       *
49       * @return the length of the field in the central directory
50       */
51      ZipShort getCentralDirectoryLength();
52  
53      /**
54       * The Header-ID.
55       *
56       * @return The HeaderId value
57       */
58      ZipShort getHeaderId();
59  
60      /**
61       * The actual data to put into local file data - without Header-ID or length specifier.
62       *
63       * @return the data
64       */
65      byte[] getLocalFileDataData();
66  
67      /**
68       * Length of the extra field in the local file data - without Header-ID or length specifier.
69       *
70       * @return the length of the field in the local file data
71       */
72      ZipShort getLocalFileDataLength();
73  
74      /**
75       * Populate data from this array as if it was in central directory data.
76       *
77       * @param buffer the buffer to read data from
78       * @param offset offset into buffer to read data
79       * @param length the length of data
80       * @throws ZipException on error
81       */
82      void parseFromCentralDirectoryData(byte[] buffer, int offset, int length) throws ZipException;
83  
84      /**
85       * Populate data from this array as if it was in local file data.
86       *
87       * @param buffer the buffer to read data from
88       * @param offset offset into buffer to read data
89       * @param length the length of data
90       * @throws ZipException on error
91       */
92      void parseFromLocalFileData(byte[] buffer, int offset, int length) throws ZipException;
93  }