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 */
019 package org.apache.commons.compress.compressors.gzip;
020
021 import java.util.LinkedHashMap;
022 import java.util.Map;
023 import org.apache.commons.compress.compressors.FileNameUtil;
024
025 /**
026 * Utility code for the gzip compression format.
027 * @ThreadSafe
028 */
029 public class GzipUtils {
030
031 private static final FileNameUtil fileNameUtil;
032
033 static {
034 // using LinkedHashMap so .tgz is preferred over .taz as
035 // compressed extension of .tar as FileNameUtil will use the
036 // first one found
037 Map<String, String> uncompressSuffix =
038 new LinkedHashMap<String, String>();
039 uncompressSuffix.put(".tgz", ".tar");
040 uncompressSuffix.put(".taz", ".tar");
041 uncompressSuffix.put(".svgz", ".svg");
042 uncompressSuffix.put(".cpgz", ".cpio");
043 uncompressSuffix.put(".wmz", ".wmf");
044 uncompressSuffix.put(".emz", ".emf");
045 uncompressSuffix.put(".gz", "");
046 uncompressSuffix.put(".z", "");
047 uncompressSuffix.put("-gz", "");
048 uncompressSuffix.put("-z", "");
049 uncompressSuffix.put("_z", "");
050 fileNameUtil = new FileNameUtil(uncompressSuffix, ".gz");
051 }
052
053 /** Private constructor to prevent instantiation of this utility class. */
054 private GzipUtils() {
055 }
056
057 /**
058 * Detects common gzip suffixes in the given filename.
059 *
060 * @param filename name of a file
061 * @return {@code true} if the filename has a common gzip suffix,
062 * {@code false} otherwise
063 */
064 public static boolean isCompressedFilename(String filename) {
065 return fileNameUtil.isCompressedFilename(filename);
066 }
067
068 /**
069 * Maps the given name of a gzip-compressed file to the name that the
070 * file should have after uncompression. Commonly used file type specific
071 * suffixes like ".tgz" or ".svgz" are automatically detected and
072 * correctly mapped. For example the name "package.tgz" is mapped to
073 * "package.tar". And any filenames with the generic ".gz" suffix
074 * (or any other generic gzip suffix) is mapped to a name without that
075 * suffix. If no gzip suffix is detected, then the filename is returned
076 * unmapped.
077 *
078 * @param filename name of a file
079 * @return name of the corresponding uncompressed file
080 */
081 public static String getUncompressedFilename(String filename) {
082 return fileNameUtil.getUncompressedFilename(filename);
083 }
084
085 /**
086 * Maps the given filename to the name that the file should have after
087 * compression with gzip. Common file types with custom suffixes for
088 * compressed versions are automatically detected and correctly mapped.
089 * For example the name "package.tar" is mapped to "package.tgz". If no
090 * custom mapping is applicable, then the default ".gz" suffix is appended
091 * to the filename.
092 *
093 * @param filename name of a file
094 * @return name of the corresponding compressed file
095 */
096 public static String getCompressedFilename(String filename) {
097 return fileNameUtil.getCompressedFilename(filename);
098 }
099
100 }