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.util.LinkedHashMap; 022import java.util.Map; 023import org.apache.commons.compress.compressors.FileNameUtil; 024 025/** 026 * Utility code for the gzip compression format. 027 * @ThreadSafe 028 */ 029public 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 final Map<String, String> uncompressSuffix = 038 new LinkedHashMap<>(); 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(final 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(final 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(final String filename) { 097 return fileNameUtil.getCompressedFilename(filename); 098 } 099 100}