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.gzip;
020
021import java.nio.charset.Charset;
022import java.nio.charset.StandardCharsets;
023import java.util.LinkedHashMap;
024import java.util.Map;
025
026import org.apache.commons.compress.compressors.FileNameUtil;
027
028/**
029 * Utility code for the gzip compression format.
030 *
031 * @ThreadSafe
032 */
033public class GzipUtils {
034
035    private static final FileNameUtil fileNameUtil;
036
037    static {
038        // using LinkedHashMap so .tgz is preferred over .taz as
039        // compressed extension of .tar as FileNameUtil will use the
040        // first one found
041        final Map<String, String> uncompressSuffix = new LinkedHashMap<>();
042        uncompressSuffix.put(".tgz", ".tar");
043        uncompressSuffix.put(".taz", ".tar");
044        uncompressSuffix.put(".svgz", ".svg");
045        uncompressSuffix.put(".cpgz", ".cpio");
046        uncompressSuffix.put(".wmz", ".wmf");
047        uncompressSuffix.put(".emz", ".emf");
048        uncompressSuffix.put(".gz", "");
049        uncompressSuffix.put(".z", "");
050        uncompressSuffix.put("-gz", "");
051        uncompressSuffix.put("-z", "");
052        uncompressSuffix.put("_z", "");
053        fileNameUtil = new FileNameUtil(uncompressSuffix, ".gz");
054    }
055
056    /**
057     * Encoding for file name and comments per the <a href="https://tools.ietf.org/html/rfc1952">GZIP File Format Specification</a>
058     */
059    static final Charset GZIP_ENCODING = StandardCharsets.ISO_8859_1;
060
061    /**
062     * Maps the given file name to the name that the file should have after compression with gzip. Common file types with custom suffixes for compressed
063     * versions are automatically detected and correctly mapped. For example the name "package.tar" is mapped to "package.tgz". If no custom mapping is
064     * applicable, then the default ".gz" suffix is appended to the file name.
065     *
066     * @param fileName name of a file
067     * @return name of the corresponding compressed file
068     * @deprecated Use {@link #getCompressedFileName(String)}.
069     */
070    @Deprecated
071    public static String getCompressedFilename(final String fileName) {
072        return fileNameUtil.getCompressedFileName(fileName);
073    }
074
075    /**
076     * Maps the given file name to the name that the file should have after compression with gzip. Common file types with custom suffixes for compressed
077     * versions are automatically detected and correctly mapped. For example the name "package.tar" is mapped to "package.tgz". If no custom mapping is
078     * applicable, then the default ".gz" suffix is appended to the file name.
079     *
080     * @param fileName name of a file
081     * @return name of the corresponding compressed file
082     * @since 1.25.0
083     */
084    public static String getCompressedFileName(final String fileName) {
085        return fileNameUtil.getCompressedFileName(fileName);
086    }
087
088    /**
089     * Maps the given name of a gzip-compressed file to the name that the file should have after uncompression. Commonly used file type specific suffixes like
090     * ".tgz" or ".svgz" are automatically detected and correctly mapped. For example the name "package.tgz" is mapped to "package.tar". And any file names with
091     * the generic ".gz" suffix (or any other generic gzip suffix) is mapped to a name without that suffix. If no gzip suffix is detected, then the file name is
092     * returned unmapped.
093     *
094     * @param fileName name of a file
095     * @return name of the corresponding uncompressed file
096     * @deprecated Use {@link #getUncompressedFileName(String)}.
097     */
098    @Deprecated
099    public static String getUncompressedFilename(final String fileName) {
100        return fileNameUtil.getUncompressedFileName(fileName);
101    }
102
103    /**
104     * Maps the given name of a gzip-compressed file to the name that the file should have after uncompression. Commonly used file type specific suffixes like
105     * ".tgz" or ".svgz" are automatically detected and correctly mapped. For example the name "package.tgz" is mapped to "package.tar". And any file names with
106     * the generic ".gz" suffix (or any other generic gzip suffix) is mapped to a name without that suffix. If no gzip suffix is detected, then the file name is
107     * returned unmapped.
108     *
109     * @param fileName name of a file
110     * @return name of the corresponding uncompressed file
111     * @since 1.25.0
112     */
113    public static String getUncompressedFileName(final String fileName) {
114        return fileNameUtil.getUncompressedFileName(fileName);
115    }
116
117    /**
118     * Detects common gzip suffixes in the given file name.
119     *
120     * @param fileName name of a file
121     * @return {@code true} if the file name has a common gzip suffix, {@code false} otherwise
122     * @deprecated Use {@link #isCompressedFileName(String)}.
123     */
124    @Deprecated
125    public static boolean isCompressedFilename(final String fileName) {
126        return fileNameUtil.isCompressedFileName(fileName);
127    }
128
129    /**
130     * Detects common gzip suffixes in the given file name.
131     *
132     * @param fileName name of a file
133     * @return {@code true} if the file name has a common gzip suffix, {@code false} otherwise
134     * @since 1.25.0
135     */
136    public static boolean isCompressedFileName(final String fileName) {
137        return fileNameUtil.isCompressedFileName(fileName);
138    }
139
140    /** Private constructor to prevent instantiation of this utility class. */
141    private GzipUtils() {
142    }
143
144}