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<ZipShort, Class<?>> implementations;
039    
040        static {
041            implementations = new HashMap<ZipShort, Class<?>>();
042            register(AsiExtraField.class);
043            register(JarMarker.class);
044            register(UnicodePathExtraField.class);
045            register(UnicodeCommentExtraField.class);
046            register(Zip64ExtendedInformationExtraField.class);
047        }
048    
049        /**
050         * Register a ZipExtraField implementation.
051         *
052         * <p>The given class must have a no-arg constructor and implement
053         * the {@link ZipExtraField ZipExtraField interface}.</p>
054         * @param c the class to register
055         */
056        public static void register(Class<?> c) {
057            try {
058                ZipExtraField ze = (ZipExtraField) c.newInstance();
059                implementations.put(ze.getHeaderId(), c);
060            } catch (ClassCastException cc) {
061                throw new RuntimeException(c + " doesn\'t implement ZipExtraField");
062            } catch (InstantiationException ie) {
063                throw new RuntimeException(c + " is not a concrete class");
064            } catch (IllegalAccessException ie) {
065                throw new RuntimeException(c + "\'s no-arg constructor is not public");
066            }
067        }
068    
069        /**
070         * Create an instance of the approriate ExtraField, falls back to
071         * {@link UnrecognizedExtraField UnrecognizedExtraField}.
072         * @param headerId the header identifier
073         * @return an instance of the appropiate ExtraField
074         * @exception InstantiationException if unable to instantiate the class
075         * @exception IllegalAccessException if not allowed to instatiate the class
076         */
077        public static ZipExtraField createExtraField(ZipShort headerId)
078            throws InstantiationException, IllegalAccessException {
079            Class<?> c = implementations.get(headerId);
080            if (c != null) {
081                return (ZipExtraField) c.newInstance();
082            }
083            UnrecognizedExtraField u = new UnrecognizedExtraField();
084            u.setHeaderId(headerId);
085            return u;
086        }
087    
088        /**
089         * Split the array into ExtraFields and populate them with the
090         * given data as local file data, throwing an exception if the
091         * data cannot be parsed.
092         * @param data an array of bytes as it appears in local file data
093         * @return an array of ExtraFields
094         * @throws ZipException on error
095         */
096        public static ZipExtraField[] parse(byte[] data) throws ZipException {
097            return parse(data, true, UnparseableExtraField.THROW);
098        }
099    
100        /**
101         * Split the array into ExtraFields and populate them with the
102         * given data, throwing an exception if the data cannot be parsed.
103         * @param data an array of bytes
104         * @param local whether data originates from the local file data
105         * or the central directory
106         * @return an array of ExtraFields
107         * @throws ZipException on error
108         */
109        public static ZipExtraField[] parse(byte[] data, boolean local)
110            throws ZipException {
111            return parse(data, local, UnparseableExtraField.THROW);
112        }
113    
114        /**
115         * Split the array into ExtraFields and populate them with the
116         * given data.
117         * @param data an array of bytes
118         * @param local whether data originates from the local file data
119         * or the central directory
120         * @param onUnparseableData what to do if the extra field data
121         * cannot be parsed.
122         * @return an array of ExtraFields
123         * @throws ZipException on error
124         *
125         * @since Apache Commons Compress 1.1
126         */
127        @SuppressWarnings("fallthrough")
128        public static ZipExtraField[] parse(byte[] data, boolean local,
129                                            UnparseableExtraField onUnparseableData)
130            throws ZipException {
131            List<ZipExtraField> v = new ArrayList<ZipExtraField>();
132            int start = 0;
133            LOOP:
134            while (start <= data.length - WORD) {
135                ZipShort headerId = new ZipShort(data, start);
136                int length = (new ZipShort(data, start + 2)).getValue();
137                if (start + WORD + length > data.length) {
138                    switch(onUnparseableData.getKey()) {
139                    case UnparseableExtraField.THROW_KEY:
140                        throw new ZipException("bad extra field starting at "
141                                               + start + ".  Block length of "
142                                               + length + " bytes exceeds remaining"
143                                               + " data of "
144                                               + (data.length - start - WORD)
145                                               + " bytes.");
146                    case UnparseableExtraField.READ_KEY:
147                        UnparseableExtraFieldData field =
148                            new UnparseableExtraFieldData();
149                        if (local) {
150                            field.parseFromLocalFileData(data, start,
151                                                         data.length - start);
152                        } else {
153                            field.parseFromCentralDirectoryData(data, start,
154                                                                data.length - start);
155                        }
156                        v.add(field);
157                        //$FALL-THROUGH$
158                    case UnparseableExtraField.SKIP_KEY:
159                        // since we cannot parse the data we must assume
160                        // the extra field consumes the whole rest of the
161                        // available data
162                        break LOOP;
163                    default:
164                        throw new ZipException("unknown UnparseableExtraField key: "
165                                               + onUnparseableData.getKey());
166                    }
167                }
168                try {
169                    ZipExtraField ze = createExtraField(headerId);
170                    if (local) {
171                        ze.parseFromLocalFileData(data, start + WORD, length);
172                    } else {
173                        ze.parseFromCentralDirectoryData(data, start + WORD,
174                                                         length);
175                    }
176                    v.add(ze);
177                } catch (InstantiationException ie) {
178                    throw new ZipException(ie.getMessage());
179                } catch (IllegalAccessException iae) {
180                    throw new ZipException(iae.getMessage());
181                }
182                start += (length + WORD);
183            }
184    
185            ZipExtraField[] result = new ZipExtraField[v.size()];
186            return v.toArray(result);
187        }
188    
189        /**
190         * Merges the local file data fields of the given ZipExtraFields.
191         * @param data an array of ExtraFiles
192         * @return an array of bytes
193         */
194        public static byte[] mergeLocalFileDataData(ZipExtraField[] data) {
195            final boolean lastIsUnparseableHolder = data.length > 0
196                && data[data.length - 1] instanceof UnparseableExtraFieldData;
197            int regularExtraFieldCount =
198                lastIsUnparseableHolder ? data.length - 1 : data.length;
199    
200            int sum = WORD * regularExtraFieldCount;
201            for (int i = 0; i < data.length; i++) {
202                sum += data[i].getLocalFileDataLength().getValue();
203            }
204    
205            byte[] result = new byte[sum];
206            int start = 0;
207            for (int i = 0; i < regularExtraFieldCount; i++) {
208                System.arraycopy(data[i].getHeaderId().getBytes(),
209                                 0, result, start, 2);
210                System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
211                                 0, result, start + 2, 2);
212                byte[] local = data[i].getLocalFileDataData();
213                System.arraycopy(local, 0, result, start + WORD, local.length);
214                start += (local.length + WORD);
215            }
216            if (lastIsUnparseableHolder) {
217                byte[] local = data[data.length - 1].getLocalFileDataData();
218                System.arraycopy(local, 0, result, start, local.length);
219            }
220            return result;
221        }
222    
223        /**
224         * Merges the central directory fields of the given ZipExtraFields.
225         * @param data an array of ExtraFields
226         * @return an array of bytes
227         */
228        public static byte[] mergeCentralDirectoryData(ZipExtraField[] data) {
229            final boolean lastIsUnparseableHolder = data.length > 0
230                && data[data.length - 1] instanceof UnparseableExtraFieldData;
231            int regularExtraFieldCount =
232                lastIsUnparseableHolder ? data.length - 1 : data.length;
233    
234            int sum = WORD * regularExtraFieldCount;
235            for (int i = 0; i < data.length; i++) {
236                sum += data[i].getCentralDirectoryLength().getValue();
237            }
238            byte[] result = new byte[sum];
239            int start = 0;
240            for (int i = 0; i < regularExtraFieldCount; i++) {
241                System.arraycopy(data[i].getHeaderId().getBytes(),
242                                 0, result, start, 2);
243                System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
244                                 0, result, start + 2, 2);
245                byte[] local = data[i].getCentralDirectoryData();
246                System.arraycopy(local, 0, result, start + WORD, local.length);
247                start += (local.length + WORD);
248            }
249            if (lastIsUnparseableHolder) {
250                byte[] local = data[data.length - 1].getCentralDirectoryData();
251                System.arraycopy(local, 0, result, start, local.length);
252            }
253            return result;
254        }
255    
256        /**
257         * "enum" for the possible actions to take if the extra field
258         * cannot be parsed.
259         *
260         * @since Apache Commons Compress 1.1
261         */
262        public static final class UnparseableExtraField {
263            /**
264             * Key for "throw an exception" action.
265             */
266            public static final int THROW_KEY = 0;
267            /**
268             * Key for "skip" action.
269             */
270            public static final int SKIP_KEY = 1;
271            /**
272             * Key for "read" action.
273             */
274            public static final int READ_KEY = 2;
275    
276            /**
277             * Throw an exception if field cannot be parsed.
278             */
279            public static final UnparseableExtraField THROW
280                = new UnparseableExtraField(THROW_KEY);
281    
282            /**
283             * Skip the extra field entirely and don't make its data
284             * available - effectively removing the extra field data.
285             */
286            public static final UnparseableExtraField SKIP
287                = new UnparseableExtraField(SKIP_KEY);
288    
289            /**
290             * Read the extra field data into an instance of {@link
291             * UnparseableExtraFieldData UnparseableExtraFieldData}.
292             */
293            public static final UnparseableExtraField READ
294                = new UnparseableExtraField(READ_KEY);
295    
296            private final int key;
297    
298            private UnparseableExtraField(int k) {
299                key = k;
300            }
301    
302            /**
303             * Key of the action to take.
304             */
305            public int getKey() { return key; }
306        }
307    }