J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2004 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.InputStream; |
| 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 encoder. This encoder |
| 34 | * was made famous by uuencode 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 file 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 | * @author Chuck McManis |
| 65 | * @see CharacterEncoder |
| 66 | * @see UUDecoder |
| 67 | */ |
| 68 | public class UUEncoder extends CharacterEncoder { |
| 69 | |
| 70 | /** |
| 71 | * This name is stored in the begin line. |
| 72 | */ |
| 73 | private String bufferName; |
| 74 | |
| 75 | /** |
| 76 | * Represents UNIX(tm) mode bits. Generally three octal digits representing |
| 77 | * read, write, and execute permission of the owner, group owner, and |
| 78 | * others. They should be interpreted as the bit groups: |
| 79 | * (owner) (group) (others) |
| 80 | * rwx rwx rwx (r = read, w = write, x = execute) |
| 81 | * |
| 82 | * By default these are set to 644 (UNIX rw-r--r-- permissions). |
| 83 | */ |
| 84 | private int mode; |
| 85 | |
| 86 | |
| 87 | /** |
| 88 | * Default - buffer begin line will be: |
| 89 | * <pre> |
| 90 | * begin 644 encoder.buf |
| 91 | * </pre> |
| 92 | */ |
| 93 | public UUEncoder() { |
| 94 | bufferName = "encoder.buf"; |
| 95 | mode = 644; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * Specifies a name for the encoded buffer, begin line will be: |
| 100 | * <pre> |
| 101 | * begin 644 [FNAME] |
| 102 | * </pre> |
| 103 | */ |
| 104 | public UUEncoder(String fname) { |
| 105 | bufferName = fname; |
| 106 | mode = 644; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Specifies a name and mode for the encoded buffer, begin line will be: |
| 111 | * <pre> |
| 112 | * begin [MODE] [FNAME] |
| 113 | * </pre> |
| 114 | */ |
| 115 | public UUEncoder(String fname, int newMode) { |
| 116 | bufferName = fname; |
| 117 | mode = newMode; |
| 118 | } |
| 119 | |
| 120 | /** number of bytes per atom in uuencoding is 3 */ |
| 121 | protected int bytesPerAtom() { |
| 122 | return (3); |
| 123 | } |
| 124 | |
| 125 | /** number of bytes per line in uuencoding is 45 */ |
| 126 | protected int bytesPerLine() { |
| 127 | return (45); |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * encodeAtom - take three bytes and encodes them into 4 characters |
| 132 | * If len is less than 3 then remaining bytes are filled with '1'. |
| 133 | * This insures that the last line won't end in spaces and potentiallly |
| 134 | * be truncated. |
| 135 | */ |
| 136 | protected void encodeAtom(OutputStream outStream, byte data[], int offset, int len) |
| 137 | throws IOException { |
| 138 | byte a, b = 1, c = 1; |
| 139 | int c1, c2, c3, c4; |
| 140 | |
| 141 | a = data[offset]; |
| 142 | if (len > 1) { |
| 143 | b = data[offset+1]; |
| 144 | } |
| 145 | if (len > 2) { |
| 146 | c = data[offset+2]; |
| 147 | } |
| 148 | |
| 149 | c1 = (a >>> 2) & 0x3f; |
| 150 | c2 = ((a << 4) & 0x30) | ((b >>> 4) & 0xf); |
| 151 | c3 = ((b << 2) & 0x3c) | ((c >>> 6) & 0x3); |
| 152 | c4 = c & 0x3f; |
| 153 | outStream.write(c1 + ' '); |
| 154 | outStream.write(c2 + ' '); |
| 155 | outStream.write(c3 + ' '); |
| 156 | outStream.write(c4 + ' '); |
| 157 | return; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Encode the line prefix which consists of the single character. The |
| 162 | * lenght is added to the value of ' ' (32 decimal) and printed. |
| 163 | */ |
| 164 | protected void encodeLinePrefix(OutputStream outStream, int length) |
| 165 | throws IOException { |
| 166 | outStream.write((length & 0x3f) + ' '); |
| 167 | } |
| 168 | |
| 169 | |
| 170 | /** |
| 171 | * The line suffix for uuencoded files is simply a new line. |
| 172 | */ |
| 173 | protected void encodeLineSuffix(OutputStream outStream) throws IOException { |
| 174 | pStream.println(); |
| 175 | } |
| 176 | |
| 177 | /** |
| 178 | * encodeBufferPrefix writes the begin line to the output stream. |
| 179 | */ |
| 180 | protected void encodeBufferPrefix(OutputStream a) throws IOException { |
| 181 | super.pStream = new PrintStream(a); |
| 182 | super.pStream.print("begin "+mode+" "); |
| 183 | if (bufferName != null) { |
| 184 | super.pStream.println(bufferName); |
| 185 | } else { |
| 186 | super.pStream.println("encoder.bin"); |
| 187 | } |
| 188 | super.pStream.flush(); |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * encodeBufferSuffix writes the single line containing space (' ') and |
| 193 | * the line containing the word 'end' to the output stream. |
| 194 | */ |
| 195 | protected void encodeBufferSuffix(OutputStream a) throws IOException { |
| 196 | super.pStream.println(" \nend"); |
| 197 | super.pStream.flush(); |
| 198 | } |
| 199 | |
| 200 | } |