1 /* 2 * Copyright (c) 2000, 2013, 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 #warn This file is preprocessed before being compiled 27 28 package java.nio.charset; 29 30 import java.nio.Buffer; 31 import java.nio.ByteBuffer; 32 import java.nio.CharBuffer; 33 import java.nio.BufferOverflowException; 34 import java.nio.BufferUnderflowException; 35 import java.lang.ref.WeakReference; 36 import java.nio.charset.CoderMalfunctionError; // javadoc 37 import java.util.Arrays; 38 39 40 /** 41 * An engine that can transform a sequence of $itypesPhrase$ into a sequence of 42 * $otypesPhrase$. 43 * 44 * <a id="steps"></a> 45 * 46 * <p> The input $itype$ sequence is provided in a $itype$ buffer or a series 47 * of such buffers. The output $otype$ sequence is written to a $otype$ buffer 48 * or a series of such buffers. $A$ $coder$ should always be used by making 49 * the following sequence of method invocations, hereinafter referred to as $a$ 50 * <i>$coding$ operation</i>: 51 * 52 * <ol> 53 * 54 * <li><p> Reset the $coder$ via the {@link #reset reset} method, unless it 55 * has not been used before; </p></li> 56 * 57 * <li><p> Invoke the {@link #$code$ $code$} method zero or more times, as 58 * long as additional input may be available, passing {@code false} for the 59 * {@code endOfInput} argument and filling the input buffer and flushing the 60 * output buffer between invocations; </p></li> 61 * 62 * <li><p> Invoke the {@link #$code$ $code$} method one final time, passing 63 * {@code true} for the {@code endOfInput} argument; and then </p></li> 64 * 65 * <li><p> Invoke the {@link #flush flush} method so that the $coder$ can 66 * flush any internal state to the output buffer. </p></li> 67 * 68 * </ol> 69 * 70 * Each invocation of the {@link #$code$ $code$} method will $code$ as many 71 * $itype$s as possible from the input buffer, writing the resulting $otype$s 72 * to the output buffer. The {@link #$code$ $code$} method returns when more 73 * input is required, when there is not enough room in the output buffer, or 74 * when $a$ $coding$ error has occurred. In each case a {@link CoderResult} 75 * object is returned to describe the reason for termination. An invoker can 76 * examine this object and fill the input buffer, flush the output buffer, or 77 * attempt to recover from $a$ $coding$ error, as appropriate, and try again. 78 * 79 * <a id="ce"></a> 80 * 81 * <p> There are two general types of $coding$ errors. If the input $itype$ 82 * sequence is $notLegal$ then the input is considered <i>malformed</i>. If 83 * the input $itype$ sequence is legal but cannot be mapped to a valid 84 * $outSequence$ then an <i>unmappable character</i> has been encountered. 85 * 86 * <a id="cae"></a> 87 * 88 * <p> How $a$ $coding$ error is handled depends upon the action requested for 89 * that type of error, which is described by an instance of the {@link 90 * CodingErrorAction} class. The possible error actions are to {@linkplain 91 * CodingErrorAction#IGNORE ignore} the erroneous input, {@linkplain 92 * CodingErrorAction#REPORT report} the error to the invoker via 93 * the returned {@link CoderResult} object, or {@linkplain CodingErrorAction#REPLACE 94 * replace} the erroneous input with the current value of the 95 * replacement $replTypeName$. The replacement 96 * 97 #if[encoder] 98 * is initially set to the $coder$'s default replacement, which often 99 * (but not always) has the initial value $defaultReplName$; 100 #end[encoder] 101 #if[decoder] 102 * has the initial value $defaultReplName$; 103 #end[decoder] 104 * 105 * its value may be changed via the {@link #replaceWith($replFQType$) 106 * replaceWith} method. 107 * 108 * <p> The default action for malformed-input and unmappable-character errors 109 * is to {@linkplain CodingErrorAction#REPORT report} them. The 110 * malformed-input error action may be changed via the {@link 111 * #onMalformedInput(CodingErrorAction) onMalformedInput} method; the 112 * unmappable-character action may be changed via the {@link 113 * #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter} method. 114 * 115 * <p> This class is designed to handle many of the details of the $coding$ 116 * process, including the implementation of error actions. $A$ $coder$ for a 117 * specific charset, which is a concrete subclass of this class, need only 118 * implement the abstract {@link #$code$Loop $code$Loop} method, which 119 * encapsulates the basic $coding$ loop. A subclass that maintains internal 120 * state should, additionally, override the {@link #implFlush implFlush} and 121 * {@link #implReset implReset} methods. 122 * 123 * <p> Instances of this class are not safe for use by multiple concurrent 124 * threads. </p> 125 * 126 * 127 * @author Mark Reinhold 128 * @author JSR-51 Expert Group 129 * @since 1.4 130 * 131 * @see ByteBuffer 132 * @see CharBuffer 133 * @see Charset 134 * @see Charset$OtherCoder$ 135 */ 136 137 public abstract class Charset$Coder$ { 138 139 private final Charset charset; 140 private final float average$ItypesPerOtype$; 141 private final float max$ItypesPerOtype$; 142 143 private $replType$ replacement; 144 private CodingErrorAction malformedInputAction 145 = CodingErrorAction.REPORT; 146 private CodingErrorAction unmappableCharacterAction 147 = CodingErrorAction.REPORT; 148 149 // Internal states 150 // 151 private static final int ST_RESET = 0; 152 private static final int ST_CODING = 1; 153 private static final int ST_END = 2; 154 private static final int ST_FLUSHED = 3; 155 156 private int state = ST_RESET; 157 158 private static String stateNames[] 159 = { "RESET", "CODING", "CODING_END", "FLUSHED" }; 160 161 162 /** 163 * Initializes a new $coder$. The new $coder$ will have the given 164 * $otypes-per-itype$ and replacement values. 165 * 166 * @param cs 167 * The charset that created this $coder$ 168 * 169 * @param average$ItypesPerOtype$ 170 * A positive float value indicating the expected number of 171 * $otype$s that will be produced for each input $itype$ 172 * 173 * @param max$ItypesPerOtype$ 174 * A positive float value indicating the maximum number of 175 * $otype$s that will be produced for each input $itype$ 176 * 177 * @param replacement 178 * The initial replacement; must not be {@code null}, must have 179 * non-zero length, must not be longer than max$ItypesPerOtype$, 180 * and must be {@linkplain #isLegalReplacement legal} 181 * 182 * @throws IllegalArgumentException 183 * If the preconditions on the parameters do not hold 184 */ 185 {#if[encoder]?protected:private} 186 Charset$Coder$(Charset cs, 187 float average$ItypesPerOtype$, 188 float max$ItypesPerOtype$, 189 $replType$ replacement) 190 { 191 this.charset = cs; 192 if (average$ItypesPerOtype$ <= 0.0f) 193 throw new IllegalArgumentException("Non-positive " 194 + "average$ItypesPerOtype$"); 195 if (max$ItypesPerOtype$ <= 0.0f) 196 throw new IllegalArgumentException("Non-positive " 197 + "max$ItypesPerOtype$"); 198 if (average$ItypesPerOtype$ > max$ItypesPerOtype$) 199 throw new IllegalArgumentException("average$ItypesPerOtype$" 200 + " exceeds " 201 + "max$ItypesPerOtype$"); 202 this.replacement = replacement; 203 this.average$ItypesPerOtype$ = average$ItypesPerOtype$; 204 this.max$ItypesPerOtype$ = max$ItypesPerOtype$; 205 replaceWith(replacement); 206 } 207 208 /** 209 * Initializes a new $coder$. The new $coder$ will have the given 210 * $otypes-per-itype$ values and its replacement will be the 211 * $replTypeName$ $defaultReplName$. 212 * 213 * @param cs 214 * The charset that created this $coder$ 215 * 216 * @param average$ItypesPerOtype$ 217 * A positive float value indicating the expected number of 218 * $otype$s that will be produced for each input $itype$ 219 * 220 * @param max$ItypesPerOtype$ 221 * A positive float value indicating the maximum number of 222 * $otype$s that will be produced for each input $itype$ 223 * 224 * @throws IllegalArgumentException 225 * If the preconditions on the parameters do not hold 226 */ 227 protected Charset$Coder$(Charset cs, 228 float average$ItypesPerOtype$, 229 float max$ItypesPerOtype$) 230 { 231 this(cs, 232 average$ItypesPerOtype$, max$ItypesPerOtype$, 233 $defaultRepl$); 234 } 235 236 /** 237 * Returns the charset that created this $coder$. 238 * 239 * @return This $coder$'s charset 240 */ 241 public final Charset charset() { 242 return charset; 243 } 244 245 /** 246 * Returns this $coder$'s replacement value. 247 * 248 * @return This $coder$'s current replacement, 249 * which is never {@code null} and is never empty 250 */ 251 public final $replType$ replacement() { 252 #if[decoder] 253 return replacement; 254 #end[decoder] 255 #if[encoder] 256 return Arrays.copyOf(replacement, replacement.$replLength$); 257 #end[encoder] 258 } 259 260 /** 261 * Changes this $coder$'s replacement value. 262 * 263 * <p> This method invokes the {@link #implReplaceWith implReplaceWith} 264 * method, passing the new replacement, after checking that the new 265 * replacement is acceptable. </p> 266 * 267 * @param newReplacement The new replacement; must not be 268 * {@code null}, must have non-zero length, 269 #if[decoder] 270 * and must not be longer than the value returned by the 271 * {@link #max$ItypesPerOtype$() max$ItypesPerOtype$} method 272 #end[decoder] 273 #if[encoder] 274 * must not be longer than the value returned by the 275 * {@link #max$ItypesPerOtype$() max$ItypesPerOtype$} method, and 276 * must be {@link #isLegalReplacement legal} 277 #end[encoder] 278 * 279 * @return This $coder$ 280 * 281 * @throws IllegalArgumentException 282 * If the preconditions on the parameter do not hold 283 */ 284 public final Charset$Coder$ replaceWith($replType$ newReplacement) { 285 if (newReplacement == null) 286 throw new IllegalArgumentException("Null replacement"); 287 int len = newReplacement.$replLength$; 288 if (len == 0) 289 throw new IllegalArgumentException("Empty replacement"); 290 if (len > max$ItypesPerOtype$) 291 throw new IllegalArgumentException("Replacement too long"); 292 #if[decoder] 293 this.replacement = newReplacement; 294 #end[decoder] 295 #if[encoder] 296 if (!isLegalReplacement(newReplacement)) 297 throw new IllegalArgumentException("Illegal replacement"); 298 this.replacement = Arrays.copyOf(newReplacement, newReplacement.$replLength$); 299 #end[encoder] 300 implReplaceWith(this.replacement); 301 return this; 302 } 303 304 /** 305 * Reports a change to this $coder$'s replacement value. 306 * 307 * <p> The default implementation of this method does nothing. This method 308 * should be overridden by $coder$s that require notification of changes to 309 * the replacement. </p> 310 * 311 * @param newReplacement The replacement value 312 */ 313 protected void implReplaceWith($replType$ newReplacement) { 314 } 315 316 #if[encoder] 317 318 private WeakReference<CharsetDecoder> cachedDecoder = null; 319 320 /** 321 * Tells whether or not the given byte array is a legal replacement value 322 * for this encoder. 323 * 324 * <p> A replacement is legal if, and only if, it is a legal sequence of 325 * bytes in this encoder's charset; that is, it must be possible to decode 326 * the replacement into one or more sixteen-bit Unicode characters. 327 * 328 * <p> The default implementation of this method is not very efficient; it 329 * should generally be overridden to improve performance. </p> 330 * 331 * @param repl The byte array to be tested 332 * 333 * @return {@code true} if, and only if, the given byte array 334 * is a legal replacement value for this encoder 335 */ 336 public boolean isLegalReplacement(byte[] repl) { 337 WeakReference<CharsetDecoder> wr = cachedDecoder; 338 CharsetDecoder dec = null; 339 if ((wr == null) || ((dec = wr.get()) == null)) { 340 dec = charset().newDecoder(); 341 dec.onMalformedInput(CodingErrorAction.REPORT); 342 dec.onUnmappableCharacter(CodingErrorAction.REPORT); 343 cachedDecoder = new WeakReference<CharsetDecoder>(dec); 344 } else { 345 dec.reset(); 346 } 347 ByteBuffer bb = ByteBuffer.wrap(repl); 348 CharBuffer cb = CharBuffer.allocate((int)(bb.remaining() 349 * dec.maxCharsPerByte())); 350 CoderResult cr = dec.decode(bb, cb, true); 351 return !cr.isError(); 352 } 353 354 #end[encoder] 355 356 /** 357 * Returns this $coder$'s current action for malformed-input errors. 358 * 359 * @return The current malformed-input action, which is never {@code null} 360 */ 361 public CodingErrorAction malformedInputAction() { 362 return malformedInputAction; 363 } 364 365 /** 366 * Changes this $coder$'s action for malformed-input errors. 367 * 368 * <p> This method invokes the {@link #implOnMalformedInput 369 * implOnMalformedInput} method, passing the new action. </p> 370 * 371 * @param newAction The new action; must not be {@code null} 372 * 373 * @return This $coder$ 374 * 375 * @throws IllegalArgumentException 376 * If the precondition on the parameter does not hold 377 */ 378 public final Charset$Coder$ onMalformedInput(CodingErrorAction newAction) { 379 if (newAction == null) 380 throw new IllegalArgumentException("Null action"); 381 malformedInputAction = newAction; 382 implOnMalformedInput(newAction); 383 return this; 384 } 385 386 /** 387 * Reports a change to this $coder$'s malformed-input action. 388 * 389 * <p> The default implementation of this method does nothing. This method 390 * should be overridden by $coder$s that require notification of changes to 391 * the malformed-input action. </p> 392 * 393 * @param newAction The new action 394 */ 395 protected void implOnMalformedInput(CodingErrorAction newAction) { } 396 397 /** 398 * Returns this $coder$'s current action for unmappable-character errors. 399 * 400 * @return The current unmappable-character action, which is never 401 * {@code null} 402 */ 403 public CodingErrorAction unmappableCharacterAction() { 404 return unmappableCharacterAction; 405 } 406 407 /** 408 * Changes this $coder$'s action for unmappable-character errors. 409 * 410 * <p> This method invokes the {@link #implOnUnmappableCharacter 411 * implOnUnmappableCharacter} method, passing the new action. </p> 412 * 413 * @param newAction The new action; must not be {@code null} 414 * 415 * @return This $coder$ 416 * 417 * @throws IllegalArgumentException 418 * If the precondition on the parameter does not hold 419 */ 420 public final Charset$Coder$ onUnmappableCharacter(CodingErrorAction 421 newAction) 422 { 423 if (newAction == null) 424 throw new IllegalArgumentException("Null action"); 425 unmappableCharacterAction = newAction; 426 implOnUnmappableCharacter(newAction); 427 return this; 428 } 429 430 /** 431 * Reports a change to this $coder$'s unmappable-character action. 432 * 433 * <p> The default implementation of this method does nothing. This method 434 * should be overridden by $coder$s that require notification of changes to 435 * the unmappable-character action. </p> 436 * 437 * @param newAction The new action 438 */ 439 protected void implOnUnmappableCharacter(CodingErrorAction newAction) { } 440 441 /** 442 * Returns the average number of $otype$s that will be produced for each 443 * $itype$ of input. This heuristic value may be used to estimate the size 444 * of the output buffer required for a given input sequence. 445 * 446 * @return The average number of $otype$s produced 447 * per $itype$ of input 448 */ 449 public final float average$ItypesPerOtype$() { 450 return average$ItypesPerOtype$; 451 } 452 453 /** 454 * Returns the maximum number of $otype$s that will be produced for each 455 * $itype$ of input. This value may be used to compute the worst-case size 456 * of the output buffer required for a given input sequence. 457 * 458 * @return The maximum number of $otype$s that will be produced per 459 * $itype$ of input 460 */ 461 public final float max$ItypesPerOtype$() { 462 return max$ItypesPerOtype$; 463 } 464 465 /** 466 * $Code$s as many $itype$s as possible from the given input buffer, 467 * writing the results to the given output buffer. 468 * 469 * <p> The buffers are read from, and written to, starting at their current 470 * positions. At most {@link Buffer#remaining in.remaining()} $itype$s 471 * will be read and at most {@link Buffer#remaining out.remaining()} 472 * $otype$s will be written. The buffers' positions will be advanced to 473 * reflect the $itype$s read and the $otype$s written, but their marks and 474 * limits will not be modified. 475 * 476 * <p> In addition to reading $itype$s from the input buffer and writing 477 * $otype$s to the output buffer, this method returns a {@link CoderResult} 478 * object to describe its reason for termination: 479 * 480 * <ul> 481 * 482 * <li><p> {@link CoderResult#UNDERFLOW} indicates that as much of the 483 * input buffer as possible has been $code$d. If there is no further 484 * input then the invoker can proceed to the next step of the 485 * <a href="#steps">$coding$ operation</a>. Otherwise this method 486 * should be invoked again with further input. </p></li> 487 * 488 * <li><p> {@link CoderResult#OVERFLOW} indicates that there is 489 * insufficient space in the output buffer to $code$ any more $itype$s. 490 * This method should be invoked again with an output buffer that has 491 * more {@linkplain Buffer#remaining remaining} $otype$s. This is 492 * typically done by draining any $code$d $otype$s from the output 493 * buffer. </p></li> 494 * 495 * <li><p> A {@linkplain CoderResult#malformedForLength 496 * malformed-input} result indicates that a malformed-input 497 * error has been detected. The malformed $itype$s begin at the input 498 * buffer's (possibly incremented) position; the number of malformed 499 * $itype$s may be determined by invoking the result object's {@link 500 * CoderResult#length() length} method. This case applies only if the 501 * {@linkplain #onMalformedInput malformed action} of this $coder$ 502 * is {@link CodingErrorAction#REPORT}; otherwise the malformed input 503 * will be ignored or replaced, as requested. </p></li> 504 * 505 * <li><p> An {@linkplain CoderResult#unmappableForLength 506 * unmappable-character} result indicates that an 507 * unmappable-character error has been detected. The $itype$s that 508 * $code$ the unmappable character begin at the input buffer's (possibly 509 * incremented) position; the number of such $itype$s may be determined 510 * by invoking the result object's {@link CoderResult#length() length} 511 * method. This case applies only if the {@linkplain #onUnmappableCharacter 512 * unmappable action} of this $coder$ is {@link 513 * CodingErrorAction#REPORT}; otherwise the unmappable character will be 514 * ignored or replaced, as requested. </p></li> 515 * 516 * </ul> 517 * 518 * In any case, if this method is to be reinvoked in the same $coding$ 519 * operation then care should be taken to preserve any $itype$s remaining 520 * in the input buffer so that they are available to the next invocation. 521 * 522 * <p> The {@code endOfInput} parameter advises this method as to whether 523 * the invoker can provide further input beyond that contained in the given 524 * input buffer. If there is a possibility of providing additional input 525 * then the invoker should pass {@code false} for this parameter; if there 526 * is no possibility of providing further input then the invoker should 527 * pass {@code true}. It is not erroneous, and in fact it is quite 528 * common, to pass {@code false} in one invocation and later discover that 529 * no further input was actually available. It is critical, however, that 530 * the final invocation of this method in a sequence of invocations always 531 * pass {@code true} so that any remaining un$code$d input will be treated 532 * as being malformed. 533 * 534 * <p> This method works by invoking the {@link #$code$Loop $code$Loop} 535 * method, interpreting its results, handling error conditions, and 536 * reinvoking it as necessary. </p> 537 * 538 * 539 * @param in 540 * The input $itype$ buffer 541 * 542 * @param out 543 * The output $otype$ buffer 544 * 545 * @param endOfInput 546 * {@code true} if, and only if, the invoker can provide no 547 * additional input $itype$s beyond those in the given buffer 548 * 549 * @return A coder-result object describing the reason for termination 550 * 551 * @throws IllegalStateException 552 * If $a$ $coding$ operation is already in progress and the previous 553 * step was an invocation neither of the {@link #reset reset} 554 * method, nor of this method with a value of {@code false} for 555 * the {@code endOfInput} parameter, nor of this method with a 556 * value of {@code true} for the {@code endOfInput} parameter 557 * but a return value indicating an incomplete $coding$ operation 558 * 559 * @throws CoderMalfunctionError 560 * If an invocation of the $code$Loop method threw 561 * an unexpected exception 562 */ 563 public final CoderResult $code$($Itype$Buffer in, $Otype$Buffer out, 564 boolean endOfInput) 565 { 566 int newState = endOfInput ? ST_END : ST_CODING; 567 if ((state != ST_RESET) && (state != ST_CODING) 568 && !(endOfInput && (state == ST_END))) 569 throwIllegalStateException(state, newState); 570 state = newState; 571 572 for (;;) { 573 574 CoderResult cr; 575 try { 576 cr = $code$Loop(in, out); 577 } catch (BufferUnderflowException x) { 578 throw new CoderMalfunctionError(x); 579 } catch (BufferOverflowException x) { 580 throw new CoderMalfunctionError(x); 581 } 582 583 if (cr.isOverflow()) 584 return cr; 585 586 if (cr.isUnderflow()) { 587 if (endOfInput && in.hasRemaining()) { 588 cr = CoderResult.malformedForLength(in.remaining()); 589 // Fall through to malformed-input case 590 } else { 591 return cr; 592 } 593 } 594 595 CodingErrorAction action = null; 596 if (cr.isMalformed()) 597 action = malformedInputAction; 598 else if (cr.isUnmappable()) 599 action = unmappableCharacterAction; 600 else 601 assert false : cr.toString(); 602 603 if (action == CodingErrorAction.REPORT) 604 return cr; 605 606 if (action == CodingErrorAction.REPLACE) { 607 if (out.remaining() < replacement.$replLength$) 608 return CoderResult.OVERFLOW; 609 out.put(replacement); 610 } 611 612 if ((action == CodingErrorAction.IGNORE) 613 || (action == CodingErrorAction.REPLACE)) { 614 // Skip erroneous input either way 615 in.position(in.position() + cr.length()); 616 continue; 617 } 618 619 assert false; 620 } 621 622 } 623 624 /** 625 * Flushes this $coder$. 626 * 627 * <p> Some $coder$s maintain internal state and may need to write some 628 * final $otype$s to the output buffer once the overall input sequence has 629 * been read. 630 * 631 * <p> Any additional output is written to the output buffer beginning at 632 * its current position. At most {@link Buffer#remaining out.remaining()} 633 * $otype$s will be written. The buffer's position will be advanced 634 * appropriately, but its mark and limit will not be modified. 635 * 636 * <p> If this method completes successfully then it returns {@link 637 * CoderResult#UNDERFLOW}. If there is insufficient room in the output 638 * buffer then it returns {@link CoderResult#OVERFLOW}. If this happens 639 * then this method must be invoked again, with an output buffer that has 640 * more room, in order to complete the current <a href="#steps">$coding$ 641 * operation</a>. 642 * 643 * <p> If this $coder$ has already been flushed then invoking this method 644 * has no effect. 645 * 646 * <p> This method invokes the {@link #implFlush implFlush} method to 647 * perform the actual flushing operation. </p> 648 * 649 * @param out 650 * The output $otype$ buffer 651 * 652 * @return A coder-result object, either {@link CoderResult#UNDERFLOW} or 653 * {@link CoderResult#OVERFLOW} 654 * 655 * @throws IllegalStateException 656 * If the previous step of the current $coding$ operation was an 657 * invocation neither of the {@link #flush flush} method nor of 658 * the three-argument {@link 659 * #$code$($Itype$Buffer,$Otype$Buffer,boolean) $code$} method 660 * with a value of {@code true} for the {@code endOfInput} 661 * parameter 662 */ 663 public final CoderResult flush($Otype$Buffer out) { 664 if (state == ST_END) { 665 CoderResult cr = implFlush(out); 666 if (cr.isUnderflow()) 667 state = ST_FLUSHED; 668 return cr; 669 } 670 671 if (state != ST_FLUSHED) 672 throwIllegalStateException(state, ST_FLUSHED); 673 674 return CoderResult.UNDERFLOW; // Already flushed 675 } 676 677 /** 678 * Flushes this $coder$. 679 * 680 * <p> The default implementation of this method does nothing, and always 681 * returns {@link CoderResult#UNDERFLOW}. This method should be overridden 682 * by $coder$s that may need to write final $otype$s to the output buffer 683 * once the entire input sequence has been read. </p> 684 * 685 * @param out 686 * The output $otype$ buffer 687 * 688 * @return A coder-result object, either {@link CoderResult#UNDERFLOW} or 689 * {@link CoderResult#OVERFLOW} 690 */ 691 protected CoderResult implFlush($Otype$Buffer out) { 692 return CoderResult.UNDERFLOW; 693 } 694 695 /** 696 * Resets this $coder$, clearing any internal state. 697 * 698 * <p> This method resets charset-independent state and also invokes the 699 * {@link #implReset() implReset} method in order to perform any 700 * charset-specific reset actions. </p> 701 * 702 * @return This $coder$ 703 * 704 */ 705 public final Charset$Coder$ reset() { 706 implReset(); 707 state = ST_RESET; 708 return this; 709 } 710 711 /** 712 * Resets this $coder$, clearing any charset-specific internal state. 713 * 714 * <p> The default implementation of this method does nothing. This method 715 * should be overridden by $coder$s that maintain internal state. </p> 716 */ 717 protected void implReset() { } 718 719 /** 720 * $Code$s one or more $itype$s into one or more $otype$s. 721 * 722 * <p> This method encapsulates the basic $coding$ loop, $coding$ as many 723 * $itype$s as possible until it either runs out of input, runs out of room 724 * in the output buffer, or encounters $a$ $coding$ error. This method is 725 * invoked by the {@link #$code$ $code$} method, which handles result 726 * interpretation and error recovery. 727 * 728 * <p> The buffers are read from, and written to, starting at their current 729 * positions. At most {@link Buffer#remaining in.remaining()} $itype$s 730 * will be read, and at most {@link Buffer#remaining out.remaining()} 731 * $otype$s will be written. The buffers' positions will be advanced to 732 * reflect the $itype$s read and the $otype$s written, but their marks and 733 * limits will not be modified. 734 * 735 * <p> This method returns a {@link CoderResult} object to describe its 736 * reason for termination, in the same manner as the {@link #$code$ $code$} 737 * method. Most implementations of this method will handle $coding$ errors 738 * by returning an appropriate result object for interpretation by the 739 * {@link #$code$ $code$} method. An optimized implementation may instead 740 * examine the relevant error action and implement that action itself. 741 * 742 * <p> An implementation of this method may perform arbitrary lookahead by 743 * returning {@link CoderResult#UNDERFLOW} until it receives sufficient 744 * input. </p> 745 * 746 * @param in 747 * The input $itype$ buffer 748 * 749 * @param out 750 * The output $otype$ buffer 751 * 752 * @return A coder-result object describing the reason for termination 753 */ 754 protected abstract CoderResult $code$Loop($Itype$Buffer in, 755 $Otype$Buffer out); 756 757 /** 758 * Convenience method that $code$s the remaining content of a single input 759 * $itype$ buffer into a newly-allocated $otype$ buffer. 760 * 761 * <p> This method implements an entire <a href="#steps">$coding$ 762 * operation</a>; that is, it resets this $coder$, then it $code$s the 763 * $itype$s in the given $itype$ buffer, and finally it flushes this 764 * $coder$. This method should therefore not be invoked if $a$ $coding$ 765 * operation is already in progress. </p> 766 * 767 * @param in 768 * The input $itype$ buffer 769 * 770 * @return A newly-allocated $otype$ buffer containing the result of the 771 * $coding$ operation. The buffer's position will be zero and its 772 * limit will follow the last $otype$ written. 773 * 774 * @throws IllegalStateException 775 * If $a$ $coding$ operation is already in progress 776 * 777 * @throws MalformedInputException 778 * If the $itype$ sequence starting at the input buffer's current 779 * position is $notLegal$ and the current malformed-input action 780 * is {@link CodingErrorAction#REPORT} 781 * 782 * @throws UnmappableCharacterException 783 * If the $itype$ sequence starting at the input buffer's current 784 * position cannot be mapped to an equivalent $otype$ sequence and 785 * the current unmappable-character action is {@link 786 * CodingErrorAction#REPORT} 787 */ 788 public final $Otype$Buffer $code$($Itype$Buffer in) 789 throws CharacterCodingException 790 { 791 int n = (int)(in.remaining() * average$ItypesPerOtype$()); 792 $Otype$Buffer out = $Otype$Buffer.allocate(n); 793 794 if ((n == 0) && (in.remaining() == 0)) 795 return out; 796 reset(); 797 for (;;) { 798 CoderResult cr = in.hasRemaining() ? 799 $code$(in, out, true) : CoderResult.UNDERFLOW; 800 if (cr.isUnderflow()) 801 cr = flush(out); 802 803 if (cr.isUnderflow()) 804 break; 805 if (cr.isOverflow()) { 806 n = 2*n + 1; // Ensure progress; n might be 0! 807 $Otype$Buffer o = $Otype$Buffer.allocate(n); 808 out.flip(); 809 o.put(out); 810 out = o; 811 continue; 812 } 813 cr.throwException(); 814 } 815 out.flip(); 816 return out; 817 } 818 819 #if[decoder] 820 821 /** 822 * Tells whether or not this decoder implements an auto-detecting charset. 823 * 824 * <p> The default implementation of this method always returns 825 * {@code false}; it should be overridden by auto-detecting decoders to 826 * return {@code true}. </p> 827 * 828 * @return {@code true} if, and only if, this decoder implements an 829 * auto-detecting charset 830 */ 831 public boolean isAutoDetecting() { 832 return false; 833 } 834 835 /** 836 * Tells whether or not this decoder has yet detected a 837 * charset <i>(optional operation)</i>. 838 * 839 * <p> If this decoder implements an auto-detecting charset then at a 840 * single point during a decoding operation this method may start returning 841 * {@code true} to indicate that a specific charset has been detected in 842 * the input byte sequence. Once this occurs, the {@link #detectedCharset 843 * detectedCharset} method may be invoked to retrieve the detected charset. 844 * 845 * <p> That this method returns {@code false} does not imply that no bytes 846 * have yet been decoded. Some auto-detecting decoders are capable of 847 * decoding some, or even all, of an input byte sequence without fixing on 848 * a particular charset. 849 * 850 * <p> The default implementation of this method always throws an {@link 851 * UnsupportedOperationException}; it should be overridden by 852 * auto-detecting decoders to return {@code true} once the input charset 853 * has been determined. </p> 854 * 855 * @return {@code true} if, and only if, this decoder has detected a 856 * specific charset 857 * 858 * @throws UnsupportedOperationException 859 * If this decoder does not implement an auto-detecting charset 860 */ 861 public boolean isCharsetDetected() { 862 throw new UnsupportedOperationException(); 863 } 864 865 /** 866 * Retrieves the charset that was detected by this 867 * decoder <i>(optional operation)</i>. 868 * 869 * <p> If this decoder implements an auto-detecting charset then this 870 * method returns the actual charset once it has been detected. After that 871 * point, this method returns the same value for the duration of the 872 * current decoding operation. If not enough input bytes have yet been 873 * read to determine the actual charset then this method throws an {@link 874 * IllegalStateException}. 875 * 876 * <p> The default implementation of this method always throws an {@link 877 * UnsupportedOperationException}; it should be overridden by 878 * auto-detecting decoders to return the appropriate value. </p> 879 * 880 * @return The charset detected by this auto-detecting decoder, 881 * or {@code null} if the charset has not yet been determined 882 * 883 * @throws IllegalStateException 884 * If insufficient bytes have been read to determine a charset 885 * 886 * @throws UnsupportedOperationException 887 * If this decoder does not implement an auto-detecting charset 888 */ 889 public Charset detectedCharset() { 890 throw new UnsupportedOperationException(); 891 } 892 893 #end[decoder] 894 895 #if[encoder] 896 897 private boolean canEncode(CharBuffer cb) { 898 if (state == ST_FLUSHED) 899 reset(); 900 else if (state != ST_RESET) 901 throwIllegalStateException(state, ST_CODING); 902 CodingErrorAction ma = malformedInputAction(); 903 CodingErrorAction ua = unmappableCharacterAction(); 904 try { 905 onMalformedInput(CodingErrorAction.REPORT); 906 onUnmappableCharacter(CodingErrorAction.REPORT); 907 encode(cb); 908 } catch (CharacterCodingException x) { 909 return false; 910 } finally { 911 onMalformedInput(ma); 912 onUnmappableCharacter(ua); 913 reset(); 914 } 915 return true; 916 } 917 918 /** 919 * Tells whether or not this encoder can encode the given character. 920 * 921 * <p> This method returns {@code false} if the given character is a 922 * surrogate character; such characters can be interpreted only when they 923 * are members of a pair consisting of a high surrogate followed by a low 924 * surrogate. The {@link #canEncode(java.lang.CharSequence) 925 * canEncode(CharSequence)} method may be used to test whether or not a 926 * character sequence can be encoded. 927 * 928 * <p> This method may modify this encoder's state; it should therefore not 929 * be invoked if an <a href="#steps">encoding operation</a> is already in 930 * progress. 931 * 932 * <p> The default implementation of this method is not very efficient; it 933 * should generally be overridden to improve performance. </p> 934 * 935 * @param c 936 * The given character 937 * 938 * @return {@code true} if, and only if, this encoder can encode 939 * the given character 940 * 941 * @throws IllegalStateException 942 * If $a$ $coding$ operation is already in progress 943 */ 944 public boolean canEncode(char c) { 945 CharBuffer cb = CharBuffer.allocate(1); 946 cb.put(c); 947 cb.flip(); 948 return canEncode(cb); 949 } 950 951 /** 952 * Tells whether or not this encoder can encode the given character 953 * sequence. 954 * 955 * <p> If this method returns {@code false} for a particular character 956 * sequence then more information about why the sequence cannot be encoded 957 * may be obtained by performing a full <a href="#steps">encoding 958 * operation</a>. 959 * 960 * <p> This method may modify this encoder's state; it should therefore not 961 * be invoked if an encoding operation is already in progress. 962 * 963 * <p> The default implementation of this method is not very efficient; it 964 * should generally be overridden to improve performance. </p> 965 * 966 * @param cs 967 * The given character sequence 968 * 969 * @return {@code true} if, and only if, this encoder can encode 970 * the given character without throwing any exceptions and without 971 * performing any replacements 972 * 973 * @throws IllegalStateException 974 * If $a$ $coding$ operation is already in progress 975 */ 976 public boolean canEncode(CharSequence cs) { 977 CharBuffer cb; 978 if (cs instanceof CharBuffer) 979 cb = ((CharBuffer)cs).duplicate(); 980 else 981 cb = CharBuffer.wrap(cs.toString()); 982 return canEncode(cb); 983 } 984 985 #end[encoder] 986 987 988 private void throwIllegalStateException(int from, int to) { 989 throw new IllegalStateException("Current state = " + stateNames[from] 990 + ", new state = " + stateNames[to]); 991 } 992 993 }