    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 */
    018package org.apache.commons.compress.archivers.zip;
    019
    020import java.util.ArrayList;
    021import java.util.List;
    022import java.util.Map;
    023import java.util.concurrent.ConcurrentHashMap;
    024import java.util.zip.ZipException;
    025
    026/**
    027 * ZipExtraField related methods
    028 * @NotThreadSafe because the HashMap is not synch.
    029 */
    030// CheckStyle:HideUtilityClassConstructorCheck OFF (bc)
    031public 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 ConcurrentHashMap<ZipShort, Class<?>>();
    042        register(AsiExtraField.class);
    043        register(X5455_ExtendedTimestamp.class);
    044        register(X7875_NewUnix.class);
    045        register(JarMarker.class);
    046        register(UnicodePathExtraField.class);
    047        register(UnicodeCommentExtraField.class);
    048        register(Zip64ExtendedInformationExtraField.class);
    049        register(X000A_NTFS.class);
    050        register(X0014_X509Certificates.class);
    051        register(X0015_CertificateIdForFile.class);
    052        register(X0016_CertificateIdForCentralDirectory.class);
    053        register(X0017_StrongEncryptionHeader.class);
    054        register(X0019_EncryptionRecipientCertificateList.class);
    055    }
    056
    057    /**
    058     * Register a ZipExtraField implementation.
    059     *
    060     * <p>The given class must have a no-arg constructor and implement
    061     * the {@link ZipExtraField ZipExtraField interface}.</p>
    062     * @param c the class to register
    063     */
    064    public static void register(final Class<?> c) {
    065        try {
    066            final ZipExtraField ze = (ZipExtraField) c.newInstance();
    067            implementations.put(ze.getHeaderId(), c);
    068        } catch (final ClassCastException cc) {
    069            throw new RuntimeException(c + " doesn\'t implement ZipExtraField");
    070        } catch (final InstantiationException ie) {
    071            throw new RuntimeException(c + " is not a concrete class");
    072        } catch (final IllegalAccessException ie) {
    073            throw new RuntimeException(c + "\'s no-arg constructor is not public");
    074        }
    075    }
    076
    077    /**
    078     * Create an instance of the appropriate ExtraField, falls back to
    079     * {@link UnrecognizedExtraField UnrecognizedExtraField}.
    080     * @param headerId the header identifier
    081     * @return an instance of the appropriate ExtraField
    082     * @throws InstantiationException if unable to instantiate the class
    083     * @throws IllegalAccessException if not allowed to instantiate the class
    084     */
    085    public static ZipExtraField createExtraField(final ZipShort headerId)
    086        throws InstantiationException, IllegalAccessException {
    087        final Class<?> c = implementations.get(headerId);
    088        if (c != null) {
    089            return (ZipExtraField) c.newInstance();
    090        }
    091        final UnrecognizedExtraField u = new UnrecognizedExtraField();
    092        u.setHeaderId(headerId);
    093        return u;
    094    }
    095
    096    /**
    097     * Split the array into ExtraFields and populate them with the
    098     * given data as local file data, throwing an exception if the
    099     * data cannot be parsed.
    100     * @param data an array of bytes as it appears in local file data
    101     * @return an array of ExtraFields
    102     * @throws ZipException on error
    103     */
    104    public static ZipExtraField[] parse(final byte[] data) throws ZipException {
    105        return parse(data, true, UnparseableExtraField.THROW);
    106    }
    107
    108    /**
    109     * Split the array into ExtraFields and populate them with the
    110     * given data, throwing an exception if the data cannot be parsed.
    111     * @param data an array of bytes
    112     * @param local whether data originates from the local file data
    113     * or the central directory
    114     * @return an array of ExtraFields
    115     * @throws ZipException on error
    116     */
    117    public static ZipExtraField[] parse(final byte[] data, final boolean local)
    118        throws ZipException {
    119        return parse(data, local, UnparseableExtraField.THROW);
    120    }
    121
    122    /**
    123     * Split the array into ExtraFields and populate them with the
    124     * given data.
    125     * @param data an array of bytes
    126     * @param local whether data originates from the local file data
    127     * or the central directory
    128     * @param onUnparseableData what to do if the extra field data
    129     * cannot be parsed.
    130     * @return an array of ExtraFields
    131     * @throws ZipException on error
    132     *
    133     * @since 1.1
    134     */
    135    public static ZipExtraField[] parse(final byte[] data, final boolean local,
    136                                        final UnparseableExtraField onUnparseableData)
    137        throws ZipException {
    138        final List<ZipExtraField> v = new ArrayList<ZipExtraField>();
    139        int start = 0;
    140        LOOP:
    141        while (start <= data.length - WORD) {
    142            final ZipShort headerId = new ZipShort(data, start);
    143            final int length = new ZipShort(data, start + 2).getValue();
    144            if (start + WORD + length > data.length) {
    145                switch(onUnparseableData.getKey()) {
    146                case UnparseableExtraField.THROW_KEY:
    147                    throw new ZipException("bad extra field starting at "
    148                                           + start + ".  Block length of "
    149                                           + length + " bytes exceeds remaining"
    150                                           + " data of "
    151                                           + (data.length - start - WORD)
    152                                           + " bytes.");
    153                case UnparseableExtraField.READ_KEY:
    154                    final UnparseableExtraFieldData field =
    155                        new UnparseableExtraFieldData();
    156                    if (local) {
    157                        field.parseFromLocalFileData(data, start,
    158                                                     data.length - start);
    159                    } else {
    160                        field.parseFromCentralDirectoryData(data, start,
    161                                                            data.length - start);
    162                    }
    163                    v.add(field);
    164                    //$FALL-THROUGH$
    165                case UnparseableExtraField.SKIP_KEY:
    166                    // since we cannot parse the data we must assume
    167                    // the extra field consumes the whole rest of the
    168                    // available data
    169                    break LOOP;
    170                default:
    171                    throw new ZipException("unknown UnparseableExtraField key: "
    172                                           + onUnparseableData.getKey());
    173                }
    174            }
    175            try {
    176                final ZipExtraField ze = createExtraField(headerId);
    177                if (local) {
    178                    ze.parseFromLocalFileData(data, start + WORD, length);
    179                } else {
    180                    ze.parseFromCentralDirectoryData(data, start + WORD,
    181                                                     length);
    182                }
    183                v.add(ze);
    184            } catch (final InstantiationException ie) {
    185                throw (ZipException) new ZipException(ie.getMessage()).initCause(ie);
    186            } catch (final IllegalAccessException iae) {
    187                throw (ZipException) new ZipException(iae.getMessage()).initCause(iae);
    188            }
    189            start += length + WORD;
    190        }
    191
    192        final ZipExtraField[] result = new ZipExtraField[v.size()];
    193        return v.toArray(result);
    194    }
    195
    196    /**
    197     * Merges the local file data fields of the given ZipExtraFields.
    198     * @param data an array of ExtraFiles
    199     * @return an array of bytes
    200     */
    201    public static byte[] mergeLocalFileDataData(final ZipExtraField[] data) {
    202        final boolean lastIsUnparseableHolder = data.length > 0
    203            && data[data.length - 1] instanceof UnparseableExtraFieldData;
    204        final int regularExtraFieldCount =
    205            lastIsUnparseableHolder ? data.length - 1 : data.length;
    206
    207        int sum = WORD * regularExtraFieldCount;
    208        for (final ZipExtraField element : data) {
    209            sum += element.getLocalFileDataLength().getValue();
    210        }
    211
    212        final byte[] result = new byte[sum];
    213        int start = 0;
    214        for (int i = 0; i < regularExtraFieldCount; i++) {
    215            System.arraycopy(data[i].getHeaderId().getBytes(),
    216                             0, result, start, 2);
    217            System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
    218                             0, result, start + 2, 2);
    219            start += WORD;
    220            final byte[] local = data[i].getLocalFileDataData();
    221            if (local != null) {
    222                System.arraycopy(local, 0, result, start, local.length);
    223                start += local.length;
    224            }
    225        }
    226        if (lastIsUnparseableHolder) {
    227            final byte[] local = data[data.length - 1].getLocalFileDataData();
    228            if (local != null) {
    229                System.arraycopy(local, 0, result, start, local.length);
    230            }
    231        }
    232        return result;
    233    }
    234
    235    /**
    236     * Merges the central directory fields of the given ZipExtraFields.
    237     * @param data an array of ExtraFields
    238     * @return an array of bytes
    239     */
    240    public static byte[] mergeCentralDirectoryData(final ZipExtraField[] data) {
    241        final boolean lastIsUnparseableHolder = data.length > 0
    242            && data[data.length - 1] instanceof UnparseableExtraFieldData;
    243        final int regularExtraFieldCount =
    244            lastIsUnparseableHolder ? data.length - 1 : data.length;
    245
    246        int sum = WORD * regularExtraFieldCount;
    247        for (final ZipExtraField element : data) {
    248            sum += element.getCentralDirectoryLength().getValue();
    249        }
    250        final byte[] result = new byte[sum];
    251        int start = 0;
    252        for (int i = 0; i < regularExtraFieldCount; i++) {
    253            System.arraycopy(data[i].getHeaderId().getBytes(),
    254                             0, result, start, 2);
    255            System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
    256                             0, result, start + 2, 2);
    257            start += WORD;
    258            final byte[] local = data[i].getCentralDirectoryData();
    259            if (local != null) {
    260                System.arraycopy(local, 0, result, start, local.length);
    261                start += local.length;
    262            }
    263        }
    264        if (lastIsUnparseableHolder) {
    265            final byte[] local = data[data.length - 1].getCentralDirectoryData();
    266            if (local != null) {
    267                System.arraycopy(local, 0, result, start, local.length);
    268            }
    269        }
    270        return result;
    271    }
    272
    273    /**
    274     * "enum" for the possible actions to take if the extra field
    275     * cannot be parsed.
    276     *
    277     * @since 1.1
    278     */
    279    public static final class UnparseableExtraField {
    280        /**
    281         * Key for "throw an exception" action.
    282         */
    283        public static final int THROW_KEY = 0;
    284        /**
    285         * Key for "skip" action.
    286         */
    287        public static final int SKIP_KEY = 1;
    288        /**
    289         * Key for "read" action.
    290         */
    291        public static final int READ_KEY = 2;
    292
    293        /**
    294         * Throw an exception if field cannot be parsed.
    295         */
    296        public static final UnparseableExtraField THROW
    297            = new UnparseableExtraField(THROW_KEY);
    298
    299        /**
    300         * Skip the extra field entirely and don't make its data
    301         * available - effectively removing the extra field data.
    302         */
    303        public static final UnparseableExtraField SKIP
    304            = new UnparseableExtraField(SKIP_KEY);
    305
    306        /**
    307         * Read the extra field data into an instance of {@link
    308         * UnparseableExtraFieldData UnparseableExtraFieldData}.
    309         */
    310        public static final UnparseableExtraField READ
    311            = new UnparseableExtraField(READ_KEY);
    312
    313        private final int key;
    314
    315        private UnparseableExtraField(final int k) {
    316            key = k;
    317        }
    318
    319        /**
    320         * Key of the action to take.
    321         * @return the key
    322         */
    323        public int getKey() { return key; }
    324    }
    325}