J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2001 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | package sun.misc; |
| 26 | |
| 27 | import java.io.PushbackInputStream; |
| 28 | import java.io.OutputStream; |
| 29 | import java.io.PrintStream; |
| 30 | import java.io.IOException; |
| 31 | |
| 32 | /** |
| 33 | * This class implements a Berkeley uu character decoder. This decoder |
| 34 | * was made famous by the uudecode program. |
| 35 | * |
| 36 | * The basic character coding is algorithmic, taking 6 bits of binary |
| 37 | * data and adding it to an ASCII ' ' (space) character. This converts |
| 38 | * these six bits into a printable representation. Note that it depends |
| 39 | * on the ASCII character encoding standard for english. Groups of three |
| 40 | * bytes are converted into 4 characters by treating the three bytes |
| 41 | * a four 6 bit groups, group 1 is byte 1's most significant six bits, |
| 42 | * group 2 is byte 1's least significant two bits plus byte 2's four |
| 43 | * most significant bits. etc. |
| 44 | * |
| 45 | * In this encoding, the buffer prefix is: |
| 46 | * <pre> |
| 47 | * begin [mode] [filename] |
| 48 | * </pre> |
| 49 | * |
| 50 | * This is followed by one or more lines of the form: |
| 51 | * <pre> |
| 52 | * (len)(data)(data)(data) ... |
| 53 | * </pre> |
| 54 | * where (len) is the number of bytes on this line. Note that groupings |
| 55 | * are always four characters, even if length is not a multiple of three |
| 56 | * bytes. When less than three characters are encoded, the values of the |
| 57 | * last remaining bytes is undefined and should be ignored. |
| 58 | * |
| 59 | * The last line of data in a uuencoded buffer is represented by a single |
| 60 | * space character. This is translated by the decoding engine to a line |
| 61 | * length of zero. This is immediately followed by a line which contains |
| 62 | * the word 'end[newline]' |
| 63 | * |
| 64 | * If an error is encountered during decoding this class throws a |
| 65 | * CEFormatException. The specific detail messages are: |
| 66 | * |
| 67 | * <pre> |
| 68 | * "UUDecoder: No begin line." |
| 69 | * "UUDecoder: Malformed begin line." |
| 70 | * "UUDecoder: Short Buffer." |
| 71 | * "UUDecoder: Bad Line Length." |
| 72 | * "UUDecoder: Missing 'end' line." |
| 73 | * </pre> |
| 74 | * |
| 75 | * @author Chuck McManis |
| 76 | * @see CharacterDecoder |
| 77 | * @see UUEncoder |
| 78 | */ |
| 79 | public class UUDecoder extends CharacterDecoder { |
| 80 | |
| 81 | /** |
| 82 | * This string contains the name that was in the buffer being decoded. |
| 83 | */ |
| 84 | public String bufferName; |
| 85 | |
| 86 | /** |
| 87 | * Represents UNIX(tm) mode bits. Generally three octal digits |
| 88 | * representing read, write, and execute permission of the owner, |
| 89 | * group owner, and others. They should be interpreted as the bit groups: |
| 90 | * <pre> |
| 91 | * (owner) (group) (others) |
| 92 | * rwx rwx rwx (r = read, w = write, x = execute) |
| 93 | *</pre> |
| 94 | * |
| 95 | */ |
| 96 | public int mode; |
| 97 | |
| 98 | |
| 99 | /** |
| 100 | * UU encoding specifies 3 bytes per atom. |
| 101 | */ |
| 102 | protected int bytesPerAtom() { |
| 103 | return (3); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * All UU lines have 45 bytes on them, for line length of 15*4+1 or 61 |
| 108 | * characters per line. |
| 109 | */ |
| 110 | protected int bytesPerLine() { |
| 111 | return (45); |
| 112 | } |
| 113 | |
| 114 | /** This is used to decode the atoms */ |
| 115 | private byte decoderBuffer[] = new byte[4]; |
| 116 | |
| 117 | /** |
| 118 | * Decode a UU atom. Note that if l is less than 3 we don't write |
| 119 | * the extra bits, however the encoder always encodes 4 character |
| 120 | * groups even when they are not needed. |
| 121 | */ |
| 122 | protected void decodeAtom(PushbackInputStream inStream, OutputStream outStream, int l) |
| 123 | throws IOException { |
| 124 | int i, c1, c2, c3, c4; |
| 125 | int a, b, c; |
| 126 | StringBuffer x = new StringBuffer(); |
| 127 | |
| 128 | for (i = 0; i < 4; i++) { |
| 129 | c1 = inStream.read(); |
| 130 | if (c1 == -1) { |
| 131 | throw new CEStreamExhausted(); |
| 132 | } |
| 133 | x.append((char)c1); |
| 134 | decoderBuffer[i] = (byte) ((c1 - ' ') & 0x3f); |
| 135 | } |
| 136 | a = ((decoderBuffer[0] << 2) & 0xfc) | ((decoderBuffer[1] >>> 4) & 3); |
| 137 | b = ((decoderBuffer[1] << 4) & 0xf0) | ((decoderBuffer[2] >>> 2) & 0xf); |
| 138 | c = ((decoderBuffer[2] << 6) & 0xc0) | (decoderBuffer[3] & 0x3f); |
| 139 | outStream.write((byte)(a & 0xff)); |
| 140 | if (l > 1) { |
| 141 | outStream.write((byte)( b & 0xff)); |
| 142 | } |
| 143 | if (l > 2) { |
| 144 | outStream.write((byte)(c&0xff)); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * For uuencoded buffers, the data begins with a line of the form: |
| 150 | * begin MODE FILENAME |
| 151 | * This line always starts in column 1. |
| 152 | */ |
| 153 | protected void decodeBufferPrefix(PushbackInputStream inStream, OutputStream outStream) throws IOException { |
| 154 | int c; |
| 155 | StringBuffer q = new StringBuffer(32); |
| 156 | String r; |
| 157 | boolean sawNewLine; |
| 158 | |
| 159 | /* |
| 160 | * This works by ripping through the buffer until it finds a 'begin' |
| 161 | * line or the end of the buffer. |
| 162 | */ |
| 163 | sawNewLine = true; |
| 164 | while (true) { |
| 165 | c = inStream.read(); |
| 166 | if (c == -1) { |
| 167 | throw new CEFormatException("UUDecoder: No begin line."); |
| 168 | } |
| 169 | if ((c == 'b') && sawNewLine){ |
| 170 | c = inStream.read(); |
| 171 | if (c == 'e') { |
| 172 | break; |
| 173 | } |
| 174 | } |
| 175 | sawNewLine = (c == '\n') || (c == '\r'); |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Now we think its begin, (we've seen ^be) so verify it here. |
| 180 | */ |
| 181 | while ((c != '\n') && (c != '\r')) { |
| 182 | c = inStream.read(); |
| 183 | if (c == -1) { |
| 184 | throw new CEFormatException("UUDecoder: No begin line."); |
| 185 | } |
| 186 | if ((c != '\n') && (c != '\r')) { |
| 187 | q.append((char)c); |
| 188 | } |
| 189 | } |
| 190 | r = q.toString(); |
| 191 | if (r.indexOf(' ') != 3) { |
| 192 | throw new CEFormatException("UUDecoder: Malformed begin line."); |
| 193 | } |
| 194 | mode = Integer.parseInt(r.substring(4,7)); |
| 195 | bufferName = r.substring(r.indexOf(' ',6)+1); |
| 196 | /* |
| 197 | * Check for \n after \r |
| 198 | */ |
| 199 | if (c == '\r') { |
| 200 | c = inStream.read (); |
| 201 | if ((c != '\n') && (c != -1)) |
| 202 | inStream.unread (c); |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * In uuencoded buffers, encoded lines start with a character that |
| 208 | * represents the number of bytes encoded in this line. The last |
| 209 | * line of input is always a line that starts with a single space |
| 210 | * character, which would be a zero length line. |
| 211 | */ |
| 212 | protected int decodeLinePrefix(PushbackInputStream inStream, OutputStream outStream) throws IOException { |
| 213 | int c; |
| 214 | |
| 215 | c = inStream.read(); |
| 216 | if (c == ' ') { |
| 217 | c = inStream.read(); /* discard the (first)trailing CR or LF */ |
| 218 | c = inStream.read(); /* check for a second one */ |
| 219 | if ((c != '\n') && (c != -1)) |
| 220 | inStream.unread (c); |
| 221 | throw new CEStreamExhausted(); |
| 222 | } else if (c == -1) { |
| 223 | throw new CEFormatException("UUDecoder: Short Buffer."); |
| 224 | } |
| 225 | |
| 226 | c = (c - ' ') & 0x3f; |
| 227 | if (c > bytesPerLine()) { |
| 228 | throw new CEFormatException("UUDecoder: Bad Line Length."); |
| 229 | } |
| 230 | return (c); |
| 231 | } |
| 232 | |
| 233 | |
| 234 | /** |
| 235 | * Find the end of the line for the next operation. |
| 236 | * The following sequences are recognized as end-of-line |
| 237 | * CR, CR LF, or LF |
| 238 | */ |
| 239 | protected void decodeLineSuffix(PushbackInputStream inStream, OutputStream outStream) throws IOException { |
| 240 | int c; |
| 241 | while (true) { |
| 242 | c = inStream.read(); |
| 243 | if (c == -1) { |
| 244 | throw new CEStreamExhausted(); |
| 245 | } |
| 246 | if (c == '\n') { |
| 247 | break; |
| 248 | } |
| 249 | if (c == '\r') { |
| 250 | c = inStream.read(); |
| 251 | if ((c != '\n') && (c != -1)) { |
| 252 | inStream.unread (c); |
| 253 | } |
| 254 | break; |
| 255 | } |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * UUencoded files have a buffer suffix which consists of the word |
| 261 | * end. This line should immediately follow the line with a single |
| 262 | * space in it. |
| 263 | */ |
| 264 | protected void decodeBufferSuffix(PushbackInputStream inStream, OutputStream outStream) throws IOException { |
| 265 | int c; |
| 266 | |
| 267 | c = inStream.read(decoderBuffer); |
| 268 | if ((decoderBuffer[0] != 'e') || (decoderBuffer[1] != 'n') || |
| 269 | (decoderBuffer[2] != 'd')) { |
| 270 | throw new CEFormatException("UUDecoder: Missing 'end' line."); |
| 271 | } |
| 272 | } |
| 273 | |
| 274 | } |