001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 */
018 package org.apache.commons.compress.archivers.zip;
019
020 import java.util.ArrayList;
021 import java.util.HashMap;
022 import java.util.List;
023 import java.util.Map;
024 import java.util.zip.ZipException;
025
026 /**
027 * ZipExtraField related methods
028 * @NotThreadSafe because the HashMap is not synch.
029 */
030 // CheckStyle:HideUtilityClassConstructorCheck OFF (bc)
031 public class ExtraFieldUtils {
032
033 private static final int WORD = 4;
034
035 /**
036 * Static registry of known extra fields.
037 */
038 private static final Map implementations;
039
040 static {
041 implementations = new HashMap();
042 register(AsiExtraField.class);
043 register(JarMarker.class);
044 register(UnicodePathExtraField.class);
045 register(UnicodeCommentExtraField.class);
046 }
047
048 /**
049 * Register a ZipExtraField implementation.
050 *
051 * <p>The given class must have a no-arg constructor and implement
052 * the {@link ZipExtraField ZipExtraField interface}.</p>
053 * @param c the class to register
054 */
055 public static void register(Class c) {
056 try {
057 ZipExtraField ze = (ZipExtraField) c.newInstance();
058 implementations.put(ze.getHeaderId(), c);
059 } catch (ClassCastException cc) {
060 throw new RuntimeException(c + " doesn\'t implement ZipExtraField");
061 } catch (InstantiationException ie) {
062 throw new RuntimeException(c + " is not a concrete class");
063 } catch (IllegalAccessException ie) {
064 throw new RuntimeException(c + "\'s no-arg constructor is not public");
065 }
066 }
067
068 /**
069 * Create an instance of the approriate ExtraField, falls back to
070 * {@link UnrecognizedExtraField UnrecognizedExtraField}.
071 * @param headerId the header identifier
072 * @return an instance of the appropiate ExtraField
073 * @exception InstantiationException if unable to instantiate the class
074 * @exception IllegalAccessException if not allowed to instatiate the class
075 */
076 public static ZipExtraField createExtraField(ZipShort headerId)
077 throws InstantiationException, IllegalAccessException {
078 Class c = (Class) implementations.get(headerId);
079 if (c != null) {
080 return (ZipExtraField) c.newInstance();
081 }
082 UnrecognizedExtraField u = new UnrecognizedExtraField();
083 u.setHeaderId(headerId);
084 return u;
085 }
086
087 /**
088 * Split the array into ExtraFields and populate them with the
089 * given data as local file data.
090 * @param data an array of bytes as it appears in local file data
091 * @return an array of ExtraFields
092 * @throws ZipException on error
093 */
094 public static ZipExtraField[] parse(byte[] data) throws ZipException {
095 return parse(data, true);
096 }
097
098 /**
099 * Split the array into ExtraFields and populate them with the
100 * given data.
101 * @param data an array of bytes
102 * @param local whether data originates from the local file data
103 * or the central directory
104 * @return an array of ExtraFields
105 * @throws ZipException on error
106 */
107 public static ZipExtraField[] parse(byte[] data, boolean local)
108 throws ZipException {
109 List v = new ArrayList();
110 int start = 0;
111 while (start <= data.length - WORD) {
112 ZipShort headerId = new ZipShort(data, start);
113 int length = (new ZipShort(data, start + 2)).getValue();
114 if (start + WORD + length > data.length) {
115 throw new ZipException("data starting at " + start
116 + " is in unknown format");
117 }
118 try {
119 ZipExtraField ze = createExtraField(headerId);
120 if (local) {
121 ze.parseFromLocalFileData(data, start + WORD, length);
122 } else {
123 ze.parseFromCentralDirectoryData(data, start + WORD,
124 length);
125 }
126 v.add(ze);
127 } catch (InstantiationException ie) {
128 throw new ZipException(ie.getMessage());
129 } catch (IllegalAccessException iae) {
130 throw new ZipException(iae.getMessage());
131 }
132 start += (length + WORD);
133 }
134
135 ZipExtraField[] result = new ZipExtraField[v.size()];
136 return (ZipExtraField[]) v.toArray(result);
137 }
138
139 /**
140 * Merges the local file data fields of the given ZipExtraFields.
141 * @param data an array of ExtraFiles
142 * @return an array of bytes
143 */
144 public static byte[] mergeLocalFileDataData(ZipExtraField[] data) {
145 int sum = WORD * data.length;
146 for (int i = 0; i < data.length; i++) {
147 sum += data[i].getLocalFileDataLength().getValue();
148 }
149 byte[] result = new byte[sum];
150 int start = 0;
151 for (int i = 0; i < data.length; i++) {
152 System.arraycopy(data[i].getHeaderId().getBytes(),
153 0, result, start, 2);
154 System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
155 0, result, start + 2, 2);
156 byte[] local = data[i].getLocalFileDataData();
157 System.arraycopy(local, 0, result, start + WORD, local.length);
158 start += (local.length + WORD);
159 }
160 return result;
161 }
162
163 /**
164 * Merges the central directory fields of the given ZipExtraFields.
165 * @param data an array of ExtraFields
166 * @return an array of bytes
167 */
168 public static byte[] mergeCentralDirectoryData(ZipExtraField[] data) {
169 int sum = WORD * data.length;
170 for (int i = 0; i < data.length; i++) {
171 sum += data[i].getCentralDirectoryLength().getValue();
172 }
173 byte[] result = new byte[sum];
174 int start = 0;
175 for (int i = 0; i < data.length; i++) {
176 System.arraycopy(data[i].getHeaderId().getBytes(),
177 0, result, start, 2);
178 System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
179 0, result, start + 2, 2);
180 byte[] local = data[i].getCentralDirectoryData();
181 System.arraycopy(local, 0, result, start + WORD, local.length);
182 start += (local.length + WORD);
183 }
184 return result;
185 }
186 }