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, throwing an exception if the
090 * data cannot be parsed.
091 * @param data an array of bytes as it appears in local file data
092 * @return an array of ExtraFields
093 * @throws ZipException on error
094 */
095 public static ZipExtraField[] parse(byte[] data) throws ZipException {
096 return parse(data, true, UnparseableExtraField.THROW);
097 }
098
099 /**
100 * Split the array into ExtraFields and populate them with the
101 * given data, throwing an exception if the data cannot be parsed.
102 * @param data an array of bytes
103 * @param local whether data originates from the local file data
104 * or the central directory
105 * @return an array of ExtraFields
106 * @throws ZipException on error
107 */
108 public static ZipExtraField[] parse(byte[] data, boolean local)
109 throws ZipException {
110 return parse(data, local, UnparseableExtraField.THROW);
111 }
112
113 /**
114 * Split the array into ExtraFields and populate them with the
115 * given data.
116 * @param data an array of bytes
117 * @param local whether data originates from the local file data
118 * or the central directory
119 * @param onUnparseableData what to do if the extra field data
120 * cannot be parsed.
121 * @return an array of ExtraFields
122 * @throws ZipException on error
123 *
124 * @since Apache Commons Compress 1.1
125 */
126 public static ZipExtraField[] parse(byte[] data, boolean local,
127 UnparseableExtraField onUnparseableData)
128 throws ZipException {
129 List v = new ArrayList();
130 int start = 0;
131 LOOP:
132 while (start <= data.length - WORD) {
133 ZipShort headerId = new ZipShort(data, start);
134 int length = (new ZipShort(data, start + 2)).getValue();
135 if (start + WORD + length > data.length) {
136 switch(onUnparseableData.getKey()) {
137 case UnparseableExtraField.THROW_KEY:
138 throw new ZipException("bad extra field starting at "
139 + start + ". Block length of "
140 + length + " bytes exceeds remaining"
141 + " data of "
142 + (data.length - start - WORD)
143 + " bytes.");
144 case UnparseableExtraField.READ_KEY:
145 UnparseableExtraFieldData field =
146 new UnparseableExtraFieldData();
147 if (local) {
148 field.parseFromLocalFileData(data, start,
149 data.length - start);
150 } else {
151 field.parseFromCentralDirectoryData(data, start,
152 data.length - start);
153 }
154 v.add(field);
155 //$FALL-THROUGH$
156 case UnparseableExtraField.SKIP_KEY:
157 // since we cannot parse the data we must assume
158 // the extra field consumes the whole rest of the
159 // available data
160 break LOOP;
161 default:
162 throw new ZipException("unknown UnparseableExtraField key: "
163 + onUnparseableData.getKey());
164 }
165 }
166 try {
167 ZipExtraField ze = createExtraField(headerId);
168 if (local) {
169 ze.parseFromLocalFileData(data, start + WORD, length);
170 } else {
171 ze.parseFromCentralDirectoryData(data, start + WORD,
172 length);
173 }
174 v.add(ze);
175 } catch (InstantiationException ie) {
176 throw new ZipException(ie.getMessage());
177 } catch (IllegalAccessException iae) {
178 throw new ZipException(iae.getMessage());
179 }
180 start += (length + WORD);
181 }
182
183 ZipExtraField[] result = new ZipExtraField[v.size()];
184 return (ZipExtraField[]) v.toArray(result);
185 }
186
187 /**
188 * Merges the local file data fields of the given ZipExtraFields.
189 * @param data an array of ExtraFiles
190 * @return an array of bytes
191 */
192 public static byte[] mergeLocalFileDataData(ZipExtraField[] data) {
193 final boolean lastIsUnparseableHolder = data.length > 0
194 && data[data.length - 1] instanceof UnparseableExtraFieldData;
195 int regularExtraFieldCount =
196 lastIsUnparseableHolder ? data.length - 1 : data.length;
197
198 int sum = WORD * regularExtraFieldCount;
199 for (int i = 0; i < data.length; i++) {
200 sum += data[i].getLocalFileDataLength().getValue();
201 }
202
203 byte[] result = new byte[sum];
204 int start = 0;
205 for (int i = 0; i < regularExtraFieldCount; i++) {
206 System.arraycopy(data[i].getHeaderId().getBytes(),
207 0, result, start, 2);
208 System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
209 0, result, start + 2, 2);
210 byte[] local = data[i].getLocalFileDataData();
211 System.arraycopy(local, 0, result, start + WORD, local.length);
212 start += (local.length + WORD);
213 }
214 if (lastIsUnparseableHolder) {
215 byte[] local = data[data.length - 1].getLocalFileDataData();
216 System.arraycopy(local, 0, result, start, local.length);
217 }
218 return result;
219 }
220
221 /**
222 * Merges the central directory fields of the given ZipExtraFields.
223 * @param data an array of ExtraFields
224 * @return an array of bytes
225 */
226 public static byte[] mergeCentralDirectoryData(ZipExtraField[] data) {
227 final boolean lastIsUnparseableHolder = data.length > 0
228 && data[data.length - 1] instanceof UnparseableExtraFieldData;
229 int regularExtraFieldCount =
230 lastIsUnparseableHolder ? data.length - 1 : data.length;
231
232 int sum = WORD * regularExtraFieldCount;
233 for (int i = 0; i < data.length; i++) {
234 sum += data[i].getCentralDirectoryLength().getValue();
235 }
236 byte[] result = new byte[sum];
237 int start = 0;
238 for (int i = 0; i < regularExtraFieldCount; i++) {
239 System.arraycopy(data[i].getHeaderId().getBytes(),
240 0, result, start, 2);
241 System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
242 0, result, start + 2, 2);
243 byte[] local = data[i].getCentralDirectoryData();
244 System.arraycopy(local, 0, result, start + WORD, local.length);
245 start += (local.length + WORD);
246 }
247 if (lastIsUnparseableHolder) {
248 byte[] local = data[data.length - 1].getCentralDirectoryData();
249 System.arraycopy(local, 0, result, start, local.length);
250 }
251 return result;
252 }
253
254 /**
255 * "enum" for the possible actions to take if the extra field
256 * cannot be parsed.
257 *
258 * @since Apache Commons Compress 1.1
259 */
260 public static final class UnparseableExtraField {
261 /**
262 * Key for "throw an exception" action.
263 */
264 public static final int THROW_KEY = 0;
265 /**
266 * Key for "skip" action.
267 */
268 public static final int SKIP_KEY = 1;
269 /**
270 * Key for "read" action.
271 */
272 public static final int READ_KEY = 2;
273
274 /**
275 * Throw an exception if field cannot be parsed.
276 */
277 public static final UnparseableExtraField THROW
278 = new UnparseableExtraField(THROW_KEY);
279
280 /**
281 * Skip the extra field entirely and don't make its data
282 * available - effectively removing the extra field data.
283 */
284 public static final UnparseableExtraField SKIP
285 = new UnparseableExtraField(SKIP_KEY);
286
287 /**
288 * Read the extra field data into an instance of {@link
289 * UnparseableExtraFieldData UnparseableExtraFieldData}.
290 */
291 public static final UnparseableExtraField READ
292 = new UnparseableExtraField(READ_KEY);
293
294 private final int key;
295
296 private UnparseableExtraField(int k) {
297 key = k;
298 }
299
300 /**
301 * Key of the action to take.
302 */
303 public int getKey() { return key; }
304 }
305 }