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 020package org.apache.commons.compress.compressors.pack200; 021 022import java.io.File; 023import java.io.FilterInputStream; 024import java.io.IOException; 025import java.io.InputStream; 026import java.util.Map; 027import java.util.jar.JarOutputStream; 028import java.util.jar.Pack200; 029 030import org.apache.commons.compress.compressors.CompressorInputStream; 031 032/** 033 * An input stream that decompresses from the Pack200 format to be read 034 * as any other stream. 035 * 036 * <p>The {@link CompressorInputStream#getCount getCount} and {@link 037 * CompressorInputStream#getBytesRead getBytesRead} methods always 038 * return 0.</p> 039 * 040 * @NotThreadSafe 041 * @since 1.3 042 */ 043public class Pack200CompressorInputStream extends CompressorInputStream { 044 private final InputStream originalInput; 045 private final StreamBridge streamBridge; 046 047 /** 048 * Decompresses the given stream, caching the decompressed data in 049 * memory. 050 * 051 * <p>When reading from a file the File-arg constructor may 052 * provide better performance.</p> 053 */ 054 public Pack200CompressorInputStream(final InputStream in) 055 throws IOException { 056 this(in, Pack200Strategy.IN_MEMORY); 057 } 058 059 /** 060 * Decompresses the given stream using the given strategy to cache 061 * the results. 062 * 063 * <p>When reading from a file the File-arg constructor may 064 * provide better performance.</p> 065 */ 066 public Pack200CompressorInputStream(final InputStream in, 067 final Pack200Strategy mode) 068 throws IOException { 069 this(in, null, mode, null); 070 } 071 072 /** 073 * Decompresses the given stream, caching the decompressed data in 074 * memory and using the given properties. 075 * 076 * <p>When reading from a file the File-arg constructor may 077 * provide better performance.</p> 078 */ 079 public Pack200CompressorInputStream(final InputStream in, 080 final Map<String, String> props) 081 throws IOException { 082 this(in, Pack200Strategy.IN_MEMORY, props); 083 } 084 085 /** 086 * Decompresses the given stream using the given strategy to cache 087 * the results and the given properties. 088 * 089 * <p>When reading from a file the File-arg constructor may 090 * provide better performance.</p> 091 */ 092 public Pack200CompressorInputStream(final InputStream in, 093 final Pack200Strategy mode, 094 final Map<String, String> props) 095 throws IOException { 096 this(in, null, mode, props); 097 } 098 099 /** 100 * Decompresses the given file, caching the decompressed data in 101 * memory. 102 */ 103 public Pack200CompressorInputStream(final File f) throws IOException { 104 this(f, Pack200Strategy.IN_MEMORY); 105 } 106 107 /** 108 * Decompresses the given file using the given strategy to cache 109 * the results. 110 */ 111 public Pack200CompressorInputStream(final File f, final Pack200Strategy mode) 112 throws IOException { 113 this(null, f, mode, null); 114 } 115 116 /** 117 * Decompresses the given file, caching the decompressed data in 118 * memory and using the given properties. 119 */ 120 public Pack200CompressorInputStream(final File f, 121 final Map<String, String> props) 122 throws IOException { 123 this(f, Pack200Strategy.IN_MEMORY, props); 124 } 125 126 /** 127 * Decompresses the given file using the given strategy to cache 128 * the results and the given properties. 129 */ 130 public Pack200CompressorInputStream(final File f, final Pack200Strategy mode, 131 final Map<String, String> props) 132 throws IOException { 133 this(null, f, mode, props); 134 } 135 136 private Pack200CompressorInputStream(final InputStream in, final File f, 137 final Pack200Strategy mode, 138 final Map<String, String> props) 139 throws IOException { 140 originalInput = in; 141 streamBridge = mode.newStreamBridge(); 142 JarOutputStream jarOut = new JarOutputStream(streamBridge); 143 Pack200.Unpacker u = Pack200.newUnpacker(); 144 if (props != null) { 145 u.properties().putAll(props); 146 } 147 if (f == null) { 148 u.unpack(new FilterInputStream(in) { 149 @Override 150 public void close() { 151 // unpack would close this stream but we 152 // want to give the user code more control 153 } 154 }, 155 jarOut); 156 } else { 157 u.unpack(f, jarOut); 158 } 159 jarOut.close(); 160 } 161 162 @Override 163 public int read() throws IOException { 164 return streamBridge.getInput().read(); 165 } 166 167 @Override 168 public int read(byte[] b) throws IOException { 169 return streamBridge.getInput().read(b); 170 } 171 172 @Override 173 public int read(byte[] b, int off, int count) throws IOException { 174 return streamBridge.getInput().read(b, off, count); 175 } 176 177 @Override 178 public int available() throws IOException { 179 return streamBridge.getInput().available(); 180 } 181 182 @Override 183 public boolean markSupported() { 184 try { 185 return streamBridge.getInput().markSupported(); 186 } catch (IOException ex) { 187 return false; 188 } 189 } 190 191 @Override 192 public void mark(int limit) { 193 try { 194 streamBridge.getInput().mark(limit); 195 } catch (IOException ex) { 196 throw new RuntimeException(ex); 197 } 198 } 199 200 @Override 201 public void reset() throws IOException { 202 streamBridge.getInput().reset(); 203 } 204 205 @Override 206 public long skip(long count) throws IOException { 207 return streamBridge.getInput().skip(count); 208 } 209 210 @Override 211 public void close() throws IOException { 212 try { 213 streamBridge.stop(); 214 } finally { 215 if (originalInput != null) { 216 originalInput.close(); 217 } 218 } 219 } 220 221 private static final byte[] CAFE_DOOD = new byte[] { 222 (byte) 0xCA, (byte) 0xFE, (byte) 0xD0, (byte) 0x0D 223 }; 224 private static final int SIG_LENGTH = CAFE_DOOD.length; 225 226 /** 227 * Checks if the signature matches what is expected for a pack200 228 * file (0xCAFED00D). 229 * 230 * @param signature 231 * the bytes to check 232 * @param length 233 * the number of bytes to check 234 * @return true, if this stream is a pack200 compressed stream, 235 * false otherwise 236 */ 237 public static boolean matches(byte[] signature, int length) { 238 if (length < SIG_LENGTH) { 239 return false; 240 } 241 242 for (int i = 0; i < SIG_LENGTH; i++) { 243 if (signature[i] != CAFE_DOOD[i]) { 244 return false; 245 } 246 } 247 248 return true; 249 } 250}