    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    }