    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 * http://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.compressors;
    020
    021import java.util.Collections;
    022import java.util.HashMap;
    023import java.util.Locale;
    024import java.util.Map;
    025
    026/**
    027 * File name mapping code for the compression formats.
    028 * @ThreadSafe
    029 * @since 1.4
    030 */
    031public class FileNameUtil {
    032
    033    /**
    034     * Map from common file name suffixes to the suffixes that identify compressed
    035     * versions of those file types. For example: from ".tar" to ".tgz".
    036     */
    037    private final Map<String, String> compressSuffix =
    038        new HashMap<>();
    039
    040    /**
    041     * Map from common file name suffixes of compressed files to the
    042     * corresponding suffixes of uncompressed files. For example: from
    043     * ".tgz" to ".tar".
    044     * <p>
    045     * This map also contains format-specific suffixes like ".gz" and "-z".
    046     * These suffixes are mapped to the empty string, as they should simply
    047     * be removed from the file name when the file is uncompressed.
    048     */
    049    private final Map<String, String> uncompressSuffix;
    050
    051    /**
    052     * Length of the longest compressed suffix.
    053     */
    054    private final int longestCompressedSuffix;
    055
    056    /**
    057     * Length of the shortest compressed suffix.
    058     */
    059    private final int shortestCompressedSuffix;
    060
    061    /**
    062     * Length of the longest uncompressed suffix.
    063     */
    064    private final int longestUncompressedSuffix;
    065
    066    /**
    067     * Length of the shortest uncompressed suffix longer than the
    068     * empty string.
    069     */
    070    private final int shortestUncompressedSuffix;
    071
    072    /**
    073     * The format's default extension.
    074     */
    075    private final String defaultExtension;
    076
    077    /**
    078     * sets up the utility with a map of known compressed to
    079     * uncompressed suffix mappings and the default extension of the
    080     * format.
    081     *
    082     * @param uncompressSuffix Map from common file name suffixes of
    083     * compressed files to the corresponding suffixes of uncompressed
    084     * files. For example: from ".tgz" to ".tar".  This map also
    085     * contains format-specific suffixes like ".gz" and "-z".  These
    086     * suffixes are mapped to the empty string, as they should simply
    087     * be removed from the file name when the file is uncompressed.
    088     *
    089     * @param defaultExtension the format's default extension like ".gz"
    090     */
    091    public FileNameUtil(final Map<String, String> uncompressSuffix,
    092                        final String defaultExtension) {
    093        this.uncompressSuffix = Collections.unmodifiableMap(uncompressSuffix);
    094        int lc = Integer.MIN_VALUE, sc = Integer.MAX_VALUE;
    095        int lu = Integer.MIN_VALUE, su = Integer.MAX_VALUE;
    096        for (final Map.Entry<String, String> ent : uncompressSuffix.entrySet()) {
    097            final int cl = ent.getKey().length();
    098            if (cl > lc) {
    099                lc = cl;
    100            }
    101            if (cl < sc) {
    102                sc = cl;
    103            }
    104
    105            final String u = ent.getValue();
    106            final int ul = u.length();
    107            if (ul > 0) {
    108                compressSuffix.computeIfAbsent(u, k -> ent.getKey());
    109                if (ul > lu) {
    110                    lu = ul;
    111                }
    112                if (ul < su) {
    113                    su = ul;
    114                }
    115            }
    116        }
    117        longestCompressedSuffix = lc;
    118        longestUncompressedSuffix = lu;
    119        shortestCompressedSuffix = sc;
    120        shortestUncompressedSuffix = su;
    121        this.defaultExtension = defaultExtension;
    122    }
    123
    124    /**
    125     * Maps the given file name to the name that the file should have after
    126     * compression. Common file types with custom suffixes for
    127     * compressed versions are automatically detected and correctly mapped.
    128     * For example the name "package.tar" is mapped to "package.tgz". If no
    129     * custom mapping is applicable, then the default ".gz" suffix is appended
    130     * to the file name.
    131     *
    132     * @param fileName name of a file
    133     * @return name of the corresponding compressed file
    134     * @deprecated Use {@link #getCompressedFileName(String)}.
    135     */
    136    @Deprecated
    137    public String getCompressedFilename(final String fileName) {
    138        return getCompressedFileName(fileName);
    139    }
    140
    141    /**
    142     * Maps the given file name to the name that the file should have after
    143     * compression. Common file types with custom suffixes for
    144     * compressed versions are automatically detected and correctly mapped.
    145     * For example the name "package.tar" is mapped to "package.tgz". If no
    146     * custom mapping is applicable, then the default ".gz" suffix is appended
    147     * to the file name.
    148     *
    149     * @param fileName name of a file
    150     * @return name of the corresponding compressed file
    151     * @since 1.25.0
    152     */
    153    public String getCompressedFileName(final String fileName) {
    154        final String lower = fileName.toLowerCase(Locale.ENGLISH);
    155        final int n = lower.length();
    156        for (int i = shortestUncompressedSuffix;
    157             i <= longestUncompressedSuffix && i < n; i++) {
    158            final String suffix = compressSuffix.get(lower.substring(n - i));
    159            if (suffix != null) {
    160                return fileName.substring(0, n - i) + suffix;
    161            }
    162        }
    163        // No custom suffix found, just append the default
    164        return fileName + defaultExtension;
    165    }
    166
    167    /**
    168     * Maps the given name of a compressed file to the name that the
    169     * file should have after uncompression. Commonly used file type specific
    170     * suffixes like ".tgz" or ".svgz" are automatically detected and
    171     * correctly mapped. For example the name "package.tgz" is mapped to
    172     * "package.tar". And any file names with the generic ".gz" suffix
    173     * (or any other generic gzip suffix) is mapped to a name without that
    174     * suffix. If no format suffix is detected, then the file name is returned
    175     * unmapped.
    176     *
    177     * @param fileName name of a file
    178     * @return name of the corresponding uncompressed file
    179     * @deprecated Use {@link #getUncompressedFileName(String)}.
    180     */
    181    @Deprecated
    182    public String getUncompressedFilename(final String fileName) {
    183        return getUncompressedFileName(fileName);
    184    }
    185
    186    /**
    187     * Maps the given name of a compressed file to the name that the
    188     * file should have after uncompression. Commonly used file type specific
    189     * suffixes like ".tgz" or ".svgz" are automatically detected and
    190     * correctly mapped. For example the name "package.tgz" is mapped to
    191     * "package.tar". And any file names with the generic ".gz" suffix
    192     * (or any other generic gzip suffix) is mapped to a name without that
    193     * suffix. If no format suffix is detected, then the file name is returned
    194     * unmapped.
    195     *
    196     * @param fileName name of a file
    197     * @return name of the corresponding uncompressed file
    198     * @since 1.25.0
    199     */
    200    public String getUncompressedFileName(final String fileName) {
    201        final String lower = fileName.toLowerCase(Locale.ENGLISH);
    202        final int n = lower.length();
    203        for (int i = shortestCompressedSuffix;
    204             i <= longestCompressedSuffix && i < n; i++) {
    205            final String suffix = uncompressSuffix.get(lower.substring(n - i));
    206            if (suffix != null) {
    207                return fileName.substring(0, n - i) + suffix;
    208            }
    209        }
    210        return fileName;
    211    }
    212
    213    /**
    214     * Detects common format suffixes in the given file name.
    215     *
    216     * @param fileName name of a file
    217     * @return {@code true} if the file name has a common format suffix,
    218     *         {@code false} otherwise
    219     * @deprecated Use {@link #isCompressedFileName(String)}.
    220     */
    221    @Deprecated
    222    public boolean isCompressedFilename(final String fileName) {
    223        return isCompressedFileName(fileName);
    224    }
    225
    226    /**
    227     * Detects common format suffixes in the given file name.
    228     *
    229     * @param fileName name of a file
    230     * @return {@code true} if the file name has a common format suffix,
    231     *         {@code false} otherwise
    232     * @since 1.25.0
    233     */
    234    public boolean isCompressedFileName(final String fileName) {
    235        final String lower = fileName.toLowerCase(Locale.ENGLISH);
    236        final int n = lower.length();
    237        for (int i = shortestCompressedSuffix;
    238             i <= longestCompressedSuffix && i < n; i++) {
    239            if (uncompressSuffix.containsKey(lower.substring(n - i))) {
    240                return true;
    241            }
    242        }
    243        return false;
    244    }
    245}