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| 1 | /* | ||
| 2 | * Copyright (c) 1995, 2005, 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 | package sun.misc; | ||
| 27 | |||
| 28 | import java.io.InputStream; | ||
| 29 | import java.io.ByteArrayInputStream; | ||
| 30 | import java.io.OutputStream; | ||
| 31 | import java.io.ByteArrayOutputStream; | ||
| 32 | import java.io.PrintStream; | ||
| 33 | import java.io.IOException; | ||
| 34 | import java.nio.ByteBuffer; | ||
| 35 | |||
| 36 | |||
| 37 | /** | ||
| 38 | * This class defines the encoding half of character encoders. | ||
| 39 | * A character encoder is an algorithim for transforming 8 bit binary | ||
| 40 | * data into text (generally 7 bit ASCII or 8 bit ISO-Latin-1 text) | ||
| 41 | * for transmition over text channels such as e-mail and network news. | ||
| 42 | * | ||
| 43 | * The character encoders have been structured around a central theme | ||
| 44 | * that, in general, the encoded text has the form: | ||
| 45 | * | ||
| 46 | * <pre> | ||
| 47 | * [Buffer Prefix] | ||
| 48 | * [Line Prefix][encoded data atoms][Line Suffix] | ||
| 49 | * [Buffer Suffix] | ||
| 50 | * </pre> | ||
| 51 | * | ||
| 52 | * In the CharacterEncoder and CharacterDecoder classes, one complete | ||
| 53 | * chunk of data is referred to as a <i>buffer</i>. Encoded buffers | ||
| 54 | * are all text, and decoded buffers (sometimes just referred to as | ||
| 55 | * buffers) are binary octets. | ||
| 56 | * | ||
| 57 | * To create a custom encoder, you must, at a minimum, overide three | ||
| 58 | * abstract methods in this class. | ||
| 59 | * <DL> | ||
| 60 | * <DD>bytesPerAtom which tells the encoder how many bytes to | ||
| 61 | * send to encodeAtom | ||
| 62 | * <DD>encodeAtom which encodes the bytes sent to it as text. | ||
| 63 | * <DD>bytesPerLine which tells the encoder the maximum number of | ||
| 64 | * bytes per line. | ||
| 65 | * </DL> | ||
| 66 | * | ||
| 67 | * Several useful encoders have already been written and are | ||
| 68 | * referenced in the See Also list below. | ||
| 69 | * | ||
| 70 | * @author Chuck McManis | ||
| 71 | * @see CharacterDecoder; | ||
| 72 | * @see UCEncoder | ||
| 73 | * @see UUEncoder | ||
| 74 | * @see BASE64Encoder | ||
| 75 | */ | ||
| 76 | public abstract class CharacterEncoder { | ||
| 77 | |||
| 78 | /** Stream that understands "printing" */ | ||
| 79 | protected PrintStream pStream; | ||
| 80 | |||
| 81 | /** Return the number of bytes per atom of encoding */ | ||
| 82 | abstract protected int bytesPerAtom(); | ||
| 83 | |||
| 84 | /** Return the number of bytes that can be encoded per line */ | ||
| 85 | abstract protected int bytesPerLine(); | ||
| 86 | |||
| 87 | /** | ||
| 88 | * Encode the prefix for the entire buffer. By default is simply | ||
| 89 | * opens the PrintStream for use by the other functions. | ||
| 90 | */ | ||
| 91 | protected void encodeBufferPrefix(OutputStream aStream) throws IOException { | ||
| 92 | pStream = new PrintStream(aStream); | ||
| 93 | } | ||
| 94 | |||
| 95 | /** | ||
| 96 | * Encode the suffix for the entire buffer. | ||
| 97 | */ | ||
| 98 | protected void encodeBufferSuffix(OutputStream aStream) throws IOException { | ||
| 99 | } | ||
| 100 | |||
| 101 | /** | ||
| 102 | * Encode the prefix that starts every output line. | ||
| 103 | */ | ||
| 104 | protected void encodeLinePrefix(OutputStream aStream, int aLength) | ||
| 105 | throws IOException { | ||
| 106 | } | ||
| 107 | |||
| 108 | /** | ||
| 109 | * Encode the suffix that ends every output line. By default | ||
| 110 | * this method just prints a <newline> into the output stream. | ||
| 111 | */ | ||
| 112 | protected void encodeLineSuffix(OutputStream aStream) throws IOException { | ||
| 113 | pStream.println(); | ||
| 114 | } | ||
| 115 | |||
| 116 | /** Encode one "atom" of information into characters. */ | ||
| 117 | abstract protected void encodeAtom(OutputStream aStream, byte someBytes[], | ||
| 118 | int anOffset, int aLength) throws IOException; | ||
| 119 | |||
| 120 | /** | ||
| 121 | * This method works around the bizarre semantics of BufferedInputStream's | ||
| 122 | * read method. | ||
| 123 | */ | ||
| 124 | protected int readFully(InputStream in, byte buffer[]) | ||
| 125 | throws java.io.IOException { | ||
| 126 | for (int i = 0; i < buffer.length; i++) { | ||
| 127 | int q = in.read(); | ||
| 128 | if (q == -1) | ||
| 129 | return i; | ||
| 130 | buffer[i] = (byte)q; | ||
| 131 | } | ||
| 132 | return buffer.length; | ||
| 133 | } | ||
| 134 | |||
| 135 | /** | ||
| 136 | * Encode bytes from the input stream, and write them as text characters | ||
| 137 | * to the output stream. This method will run until it exhausts the | ||
| 138 | * input stream, but does not print the line suffix for a final | ||
| 139 | * line that is shorter than bytesPerLine(). | ||
| 140 | */ | ||
| 141 | public void encode(InputStream inStream, OutputStream outStream) | ||
| 142 | throws IOException { | ||
| 143 | int j; | ||
| 144 | int numBytes; | ||
| 145 | byte tmpbuffer[] = new byte[bytesPerLine()]; | ||
| 146 | |||
| 147 | encodeBufferPrefix(outStream); | ||
| 148 | |||
| 149 | while (true) { | ||
| 150 | numBytes = readFully(inStream, tmpbuffer); | ||
| 151 | if (numBytes == 0) { | ||
| 152 | break; | ||
| 153 | } | ||
| 154 | encodeLinePrefix(outStream, numBytes); | ||
| 155 | for (j = 0; j < numBytes; j += bytesPerAtom()) { | ||
| 156 | |||
| 157 | if ((j + bytesPerAtom()) <= numBytes) { | ||
| 158 | encodeAtom(outStream, tmpbuffer, j, bytesPerAtom()); | ||
| 159 | } else { | ||
| 160 | encodeAtom(outStream, tmpbuffer, j, (numBytes)- j); | ||
| 161 | } | ||
| 162 | } | ||
| 163 | if (numBytes < bytesPerLine()) { | ||
| 164 | break; | ||
| 165 | } else { | ||
| 166 | encodeLineSuffix(outStream); | ||
| 167 | } | ||
| 168 | } | ||
| 169 | encodeBufferSuffix(outStream); | ||
| 170 | } | ||
| 171 | |||
| 172 | /** | ||
| 173 | * Encode the buffer in <i>aBuffer</i> and write the encoded | ||
| 174 | * result to the OutputStream <i>aStream</i>. | ||
| 175 | */ | ||
| 176 | public void encode(byte aBuffer[], OutputStream aStream) | ||
| 177 | throws IOException { | ||
| 178 | ByteArrayInputStream inStream = new ByteArrayInputStream(aBuffer); | ||
| 179 | encode(inStream, aStream); | ||
| 180 | } | ||
| 181 | |||
| 182 | /** | ||
| 183 | * A 'streamless' version of encode that simply takes a buffer of | ||
| 184 | * bytes and returns a string containing the encoded buffer. | ||
| 185 | */ | ||
| 186 | public String encode(byte aBuffer[]) { | ||
| 187 | ByteArrayOutputStream outStream = new ByteArrayOutputStream(); | ||
| 188 | ByteArrayInputStream inStream = new ByteArrayInputStream(aBuffer); | ||
| 189 | String retVal = null; | ||
| 190 | try { | ||
| 191 | encode(inStream, outStream); | ||
| 192 | // explicit ascii->unicode conversion | ||
| 193 | retVal = outStream.toString("8859_1"); | ||
| 194 | } catch (Exception IOException) { | ||
| 195 | // This should never happen. | ||
| 196 | throw new Error("CharacterEncoder.encode internal error"); | ||
| 197 | } | ||
| 198 | return (retVal); | ||
| 199 | } | ||
| 200 | |||
| 201 | /** | ||
| 202 | * Return a byte array from the remaining bytes in this ByteBuffer. | ||
| 203 | * <P> | ||
| 204 | * The ByteBuffer's position will be advanced to ByteBuffer's limit. | ||
| 205 | * <P> | ||
| 206 | * To avoid an extra copy, the implementation will attempt to return the | ||
| 207 | * byte array backing the ByteBuffer. If this is not possible, a | ||
| 208 | * new byte array will be created. | ||
| 209 | */ | ||
| 210 | private byte [] getBytes(ByteBuffer bb) { | ||
| 211 | /* | ||
| 212 | * This should never return a BufferOverflowException, as we're | ||
| 213 | * careful to allocate just the right amount. | ||
| 214 | */ | ||
| 215 | byte [] buf = null; | ||
| 216 | |||
| 217 | /* | ||
| 218 | * If it has a usable backing byte buffer, use it. Use only | ||
| 219 | * if the array exactly represents the current ByteBuffer. | ||
| 220 | */ | ||
| 221 | if (bb.hasArray()) { | ||
| 222 | byte [] tmp = bb.array(); | ||
| 223 | if ((tmp.length == bb.capacity()) && | ||
| 224 | (tmp.length == bb.remaining())) { | ||
| 225 | buf = tmp; | ||
| 226 | bb.position(bb.limit()); | ||
| 227 | } | ||
| 228 | } | ||
| 229 | |||
| 230 | if (buf == null) { | ||
| 231 | /* | ||
| 232 | * This class doesn't have a concept of encode(buf, len, off), | ||
| 233 | * so if we have a partial buffer, we must reallocate | ||
| 234 | * space. | ||
| 235 | */ | ||
| 236 | buf = new byte[bb.remaining()]; | ||
| 237 | |||
| 238 | /* | ||
| 239 | * position() automatically updated | ||
| 240 | */ | ||
| 241 | bb.get(buf); | ||
| 242 | } | ||
| 243 | |||
| 244 | return buf; | ||
| 245 | } | ||
| 246 | |||
| 247 | /** | ||
| 248 | * Encode the <i>aBuffer</i> ByteBuffer and write the encoded | ||
| 249 | * result to the OutputStream <i>aStream</i>. | ||
| 250 | * <P> | ||
| 251 | * The ByteBuffer's position will be advanced to ByteBuffer's limit. | ||
| 252 | */ | ||
| 253 | public void encode(ByteBuffer aBuffer, OutputStream aStream) | ||
| 254 | throws IOException { | ||
| 255 | byte [] buf = getBytes(aBuffer); | ||
| 256 | encode(buf, aStream); | ||
| 257 | } | ||
| 258 | |||
| 259 | /** | ||
| 260 | * A 'streamless' version of encode that simply takes a ByteBuffer | ||
| 261 | * and returns a string containing the encoded buffer. | ||
| 262 | * <P> | ||
| 263 | * The ByteBuffer's position will be advanced to ByteBuffer's limit. | ||
| 264 | */ | ||
| 265 | public String encode(ByteBuffer aBuffer) { | ||
| 266 | byte [] buf = getBytes(aBuffer); | ||
| 267 | return encode(buf); | ||
| 268 | } | ||
| 269 | |||
| 270 | /** | ||
| 271 | * Encode bytes from the input stream, and write them as text characters | ||
| 272 | * to the output stream. This method will run until it exhausts the | ||
| 273 | * input stream. It differs from encode in that it will add the | ||
| 274 | * line at the end of a final line that is shorter than bytesPerLine(). | ||
| 275 | */ | ||
| 276 | public void encodeBuffer(InputStream inStream, OutputStream outStream) | ||
| 277 | throws IOException { | ||
| 278 | int j; | ||
| 279 | int numBytes; | ||
| 280 | byte tmpbuffer[] = new byte[bytesPerLine()]; | ||
| 281 | |||
| 282 | encodeBufferPrefix(outStream); | ||
| 283 | |||
| 284 | while (true) { | ||
| 285 | numBytes = readFully(inStream, tmpbuffer); | ||
| 286 | if (numBytes == 0) { | ||
| 287 | break; | ||
| 288 | } | ||
| 289 | encodeLinePrefix(outStream, numBytes); | ||
| 290 | for (j = 0; j < numBytes; j += bytesPerAtom()) { | ||
| 291 | if ((j + bytesPerAtom()) <= numBytes) { | ||
| 292 | encodeAtom(outStream, tmpbuffer, j, bytesPerAtom()); | ||
| 293 | } else { | ||
| 294 | encodeAtom(outStream, tmpbuffer, j, (numBytes)- j); | ||
| 295 | } | ||
| 296 | } | ||
| 297 | encodeLineSuffix(outStream); | ||
| 298 | if (numBytes < bytesPerLine()) { | ||
| 299 | break; | ||
| 300 | } | ||
| 301 | } | ||
| 302 | encodeBufferSuffix(outStream); | ||
| 303 | } | ||
| 304 | |||
| 305 | /** | ||
| 306 | * Encode the buffer in <i>aBuffer</i> and write the encoded | ||
| 307 | * result to the OutputStream <i>aStream</i>. | ||
| 308 | */ | ||
| 309 | public void encodeBuffer(byte aBuffer[], OutputStream aStream) | ||
| 310 | throws IOException { | ||
| 311 | ByteArrayInputStream inStream = new ByteArrayInputStream(aBuffer); | ||
| 312 | encodeBuffer(inStream, aStream); | ||
| 313 | } | ||
| 314 | |||
| 315 | /** | ||
| 316 | * A 'streamless' version of encode that simply takes a buffer of | ||
| 317 | * bytes and returns a string containing the encoded buffer. | ||
| 318 | */ | ||
| 319 | public String encodeBuffer(byte aBuffer[]) { | ||
| 320 | ByteArrayOutputStream outStream = new ByteArrayOutputStream(); | ||
| 321 | ByteArrayInputStream inStream = new ByteArrayInputStream(aBuffer); | ||
| 322 | try { | ||
| 323 | encodeBuffer(inStream, outStream); | ||
| 324 | } catch (Exception IOException) { | ||
| 325 | // This should never happen. | ||
| 326 | throw new Error("CharacterEncoder.encodeBuffer internal error"); | ||
| 327 | } | ||
| 328 | return (outStream.toString()); | ||
| 329 | } | ||
| 330 | |||
| 331 | /** | ||
| 332 | * Encode the <i>aBuffer</i> ByteBuffer and write the encoded | ||
| 333 | * result to the OutputStream <i>aStream</i>. | ||
| 334 | * <P> | ||
| 335 | * The ByteBuffer's position will be advanced to ByteBuffer's limit. | ||
| 336 | */ | ||
| 337 | public void encodeBuffer(ByteBuffer aBuffer, OutputStream aStream) | ||
| 338 | throws IOException { | ||
| 339 | byte [] buf = getBytes(aBuffer); | ||
| 340 | encodeBuffer(buf, aStream); | ||
| 341 | } | ||
| 342 | |||
| 343 | /** | ||
| 344 | * A 'streamless' version of encode that simply takes a ByteBuffer | ||
| 345 | * and returns a string containing the encoded buffer. | ||
| 346 | * <P> | ||
| 347 | * The ByteBuffer's position will be advanced to ByteBuffer's limit. | ||
| 348 | */ | ||
| 349 | public String encodeBuffer(ByteBuffer aBuffer) { | ||
| 350 | byte [] buf = getBytes(aBuffer); | ||
| 351 | return encodeBuffer(buf); | ||
| 352 | } | ||
| 353 | |||
| 354 | } | ||