1 /* 2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * @(#)UUDecoderStream.java 1.8 02/07/08 28 */ 29 30 31 32 package com.sun.xml.internal.messaging.saaj.packaging.mime.util; 33 34 import java.io.*; 35 36 /** 37 * This class implements a UUDecoder. It is implemented as 38 * a FilterInputStream, so one can just wrap this class around 39 * any input stream and read bytes from this filter. The decoding 40 * is done as the bytes are read out. 41 * 42 * @author John Mani 43 * @author Bill Shannon 44 */ 45 46 public class UUDecoderStream extends FilterInputStream { 47 private String name; 48 private int mode; 49 50 private byte[] buffer; // cache of decoded bytes 51 private int bufsize = 0; // size of the cache 52 private int index = 0; // index into the cache 53 private boolean gotPrefix = false; 54 private boolean gotEnd = false; 55 private LineInputStream lin; 56 57 /** 58 * Create a UUdecoder that decodes the specified input stream 59 * @param in the input stream 60 */ 61 public UUDecoderStream(InputStream in) { 62 super(in); 63 lin = new LineInputStream(in); 64 buffer = new byte[45]; // max decoded chars in a line = 45 65 } 66 67 /** 68 * Read the next decoded byte from this input stream. The byte 69 * is returned as an <code>int</code> in the range <code>0</code> 70 * to <code>255</code>. If no byte is available because the end of 71 * the stream has been reached, the value <code>-1</code> is returned. 72 * This method blocks until input data is available, the end of the 73 * stream is detected, or an exception is thrown. 74 * 75 * @return next byte of data, or <code>-1</code> if the end of 76 * stream is reached. 77 * @exception IOException if an I/O error occurs. 78 * @see java.io.FilterInputStream#in 79 */ 80 81 @Override 82 public int read() throws IOException { 83 if (index >= bufsize) { 84 readPrefix(); 85 if (!decode()) 86 return -1; 87 index = 0; // reset index into buffer 88 } 89 return buffer[index++] & 0xff; // return lower byte 90 } 91 92 @Override 93 public int read(byte[] buf, int off, int len) throws IOException { 94 int i, c; 95 for (i = 0; i < len; i++) { 96 if ((c = read()) == -1) { 97 if (i == 0) // At end of stream, so we should 98 i = -1; // return -1, NOT 0. 99 break; 100 } 101 buf[off+i] = (byte)c; 102 } 103 return i; 104 } 105 106 @Override 107 public boolean markSupported() { 108 return false; 109 } 110 111 @Override 112 public int available() throws IOException { 113 // This is only an estimate, since in.available() 114 // might include CRLFs too .. 115 return ((in.available() * 3)/4 + (bufsize-index)); 116 } 117 118 /** 119 * Get the "name" field from the prefix. This is meant to 120 * be the pathname of the decoded file 121 * 122 * @return name of decoded file 123 * @exception IOException if an I/O error occurs. 124 */ 125 public String getName() throws IOException { 126 readPrefix(); 127 return name; 128 } 129 130 /** 131 * Get the "mode" field from the prefix. This is the permission 132 * mode of the source file. 133 * 134 * @return permission mode of source file 135 * @exception IOException if an I/O error occurs. 136 */ 137 public int getMode() throws IOException { 138 readPrefix(); 139 return mode; 140 } 141 142 /** 143 * UUencoded streams start off with the line: 144 * "begin <mode> <filename>" 145 * Search for this prefix and gobble it up. 146 */ 147 private void readPrefix() throws IOException { 148 if (gotPrefix) // got the prefix 149 return; 150 151 String s; 152 for (;;) { 153 // read till we get the prefix: "begin MODE FILENAME" 154 s = lin.readLine(); // NOTE: readLine consumes CRLF pairs too 155 if (s == null) 156 throw new IOException("UUDecoder error: No Begin"); 157 if (s.regionMatches(true, 0, "begin", 0, 5)) { 158 try { 159 mode = Integer.parseInt(s.substring(6,9)); 160 } catch (NumberFormatException ex) { 161 throw new IOException("UUDecoder error: " + ex.toString()); 162 } 163 name = s.substring(10); 164 gotPrefix = true; 165 return; 166 } 167 } 168 } 169 170 private boolean decode() throws IOException { 171 172 if (gotEnd) 173 return false; 174 bufsize = 0; 175 String line; 176 do { 177 line = lin.readLine(); 178 179 /* 180 * Improperly encoded data sometimes omits the zero length 181 * line that starts with a space character, we detect the 182 * following "end" line here. 183 */ 184 if (line == null) 185 throw new IOException("Missing End"); 186 if (line.regionMatches(true, 0, "end", 0, 3)) { 187 gotEnd = true; 188 return false; 189 } 190 } while (line.length() == 0); 191 int count = line.charAt(0); 192 if (count < ' ') 193 throw new IOException("Buffer format error"); 194 195 /* 196 * The first character in a line is the number of original (not 197 * the encoded atoms) characters in the line. Note that all the 198 * code below has to handle the <SPACE> character that indicates 199 * end of encoded stream. 200 */ 201 count = (count - ' ') & 0x3f; 202 203 if (count == 0) { 204 line = lin.readLine(); 205 if (line == null || !line.regionMatches(true, 0, "end", 0, 3)) 206 throw new IOException("Missing End"); 207 gotEnd = true; 208 return false; 209 } 210 211 int need = ((count * 8)+5)/6; 212 //System.out.println("count " + count + ", need " + need + ", len " + line.length()); 213 if (line.length() < need + 1) 214 throw new IOException("Short buffer error"); 215 216 int i = 1; 217 byte a, b; 218 /* 219 * A correct uuencoder always encodes 3 characters at a time, even 220 * if there aren't 3 characters left. But since some people out 221 * there have broken uuencoders we handle the case where they 222 * don't include these "unnecessary" characters. 223 */ 224 while (bufsize < count) { 225 // continue decoding until we get 'count' decoded chars 226 a = (byte)((line.charAt(i++) - ' ') & 0x3f); 227 b = (byte)((line.charAt(i++) - ' ') & 0x3f); 228 buffer[bufsize++] = (byte)(((a << 2) & 0xfc) | ((b >>> 4) & 3)); 229 230 if (bufsize < count) { 231 a = b; 232 b = (byte)((line.charAt(i++) - ' ') & 0x3f); 233 buffer[bufsize++] = 234 (byte)(((a << 4) & 0xf0) | ((b >>> 2) & 0xf)); 235 } 236 237 if (bufsize < count) { 238 a = b; 239 b = (byte)((line.charAt(i++) - ' ') & 0x3f); 240 buffer[bufsize++] = (byte)(((a << 6) & 0xc0) | (b & 0x3f)); 241 } 242 } 243 return true; 244 } 245 246 /*** begin TEST program ***** 247 public static void main(String argv[]) throws Exception { 248 FileInputStream infile = new FileInputStream(argv[0]); 249 UUDecoderStream decoder = new UUDecoderStream(infile); 250 int c; 251 252 try { 253 while ((c = decoder.read()) != -1) 254 System.out.write(c); 255 System.out.flush(); 256 } catch (Exception e) { 257 e.printStackTrace(); 258 } 259 } 260 **** end TEST program ****/ 261 }