1 /* 2 *************************************************************************** 3 * Copyright (C) 1999-2008 International Business Machines Corporation * 4 * and others. All rights reserved. * 5 *************************************************************************** 6 7 ********************************************************************** 8 * Date Name Description 9 * 10/22/99 alan Creation. 10 * 11/11/99 rgillam Complete port from Java. 11 ********************************************************************** 12 */ 13 14 #ifndef RBBI_H 15 #define RBBI_H 16 17 #include "unicode/utypes.h" 18 19 /** 20 * \file 21 * \brief C++ API: Rule Based Break Iterator 22 */ 23 24 #if !UCONFIG_NO_BREAK_ITERATION 25 26 #include "unicode/brkiter.h" 27 #include "unicode/udata.h" 28 #include "unicode/parseerr.h" 29 #include "unicode/schriter.h" 30 #include "unicode/uchriter.h" 31 32 33 struct UTrie; 34 35 U_NAMESPACE_BEGIN 36 37 /** @internal */ 38 struct RBBIDataHeader; 39 class RuleBasedBreakIteratorTables; 40 class BreakIterator; 41 class RBBIDataWrapper; 42 class UStack; 43 class LanguageBreakEngine; 44 class UnhandledEngine; 45 struct RBBIStateTable; 46 47 48 49 50 /** 51 * 52 * A subclass of BreakIterator whose behavior is specified using a list of rules. 53 * <p>Instances of this class are most commonly created by the factory methods of 54 * BreakIterator::createWordInstance(), BreakIterator::createLineInstance(), etc., 55 * and then used via the abstract API in class BreakIterator</p> 56 * 57 * <p>See the ICU User Guide for information on Break Iterator Rules.</p> 58 * 59 * <p>This class is not intended to be subclassed. (Class DictionaryBasedBreakIterator 60 * is a subclass, but that relationship is effectively internal to the ICU 61 * implementation. The subclassing interface to RulesBasedBreakIterator is 62 * not part of the ICU API, and may not remain stable.</p> 63 * 64 */ 65 class U_COMMON_API RuleBasedBreakIterator : public BreakIterator { 66 67 protected: 68 /** 69 * The UText through which this BreakIterator accesses the text 70 * @internal 71 */ 72 UText *fText; 73 74 /** 75 * A character iterator that refers to the same text as the UText, above. 76 * Only included for compatibility with old API, which was based on CharacterIterators. 77 * Value may be adopted from outside, or one of fSCharIter or fDCharIter, below. 78 */ 79 CharacterIterator *fCharIter; 80 81 /** 82 * When the input text is provided by a UnicodeString, this will point to 83 * a characterIterator that wraps that data. Needed only for the 84 * implementation of getText(), a backwards compatibility issue. 85 */ 86 StringCharacterIterator *fSCharIter; 87 88 /** 89 * When the input text is provided by a UText, this 90 * dummy CharacterIterator over an empty string will 91 * be returned from getText() 92 */ 93 UCharCharacterIterator *fDCharIter; 94 95 /** 96 * The rule data for this BreakIterator instance 97 * @internal 98 */ 99 RBBIDataWrapper *fData; 100 101 /** Index of the Rule {tag} values for the most recent match. 102 * @internal 103 */ 104 int32_t fLastRuleStatusIndex; 105 106 /** 107 * Rule tag value valid flag. 108 * Some iterator operations don't intrinsically set the correct tag value. 109 * This flag lets us lazily compute the value if we are ever asked for it. 110 * @internal 111 */ 112 UBool fLastStatusIndexValid; 113 114 /** 115 * Counter for the number of characters encountered with the "dictionary" 116 * flag set. 117 * @internal 118 */ 119 uint32_t fDictionaryCharCount; 120 121 /** 122 * When a range of characters is divided up using the dictionary, the break 123 * positions that are discovered are stored here, preventing us from having 124 * to use either the dictionary or the state table again until the iterator 125 * leaves this range of text. Has the most impact for line breaking. 126 * @internal 127 */ 128 int32_t* fCachedBreakPositions; 129 130 /** 131 * The number of elements in fCachedBreakPositions 132 * @internal 133 */ 134 int32_t fNumCachedBreakPositions; 135 136 /** 137 * if fCachedBreakPositions is not null, this indicates which item in the 138 * cache the current iteration position refers to 139 * @internal 140 */ 141 int32_t fPositionInCache; 142 143 /** 144 * 145 * If present, UStack of LanguageBreakEngine objects that might handle 146 * dictionary characters. Searched from top to bottom to find an object to 147 * handle a given character. 148 * @internal 149 */ 150 UStack *fLanguageBreakEngines; 151 152 /** 153 * 154 * If present, the special LanguageBreakEngine used for handling 155 * characters that are in the dictionary set, but not handled by any 156 * LangugageBreakEngine. 157 * @internal 158 */ 159 UnhandledEngine *fUnhandledBreakEngine; 160 161 /** 162 * 163 * The type of the break iterator, or -1 if it has not been set. 164 * @internal 165 */ 166 int32_t fBreakType; 167 168 protected: 169 //======================================================================= 170 // constructors 171 //======================================================================= 172 173 /** 174 * Constant to be used in the constructor 175 * RuleBasedBreakIterator(RBBIDataHeader*, EDontAdopt, UErrorCode &); 176 * which does not adopt the memory indicated by the RBBIDataHeader* 177 * parameter. 178 * 179 * @internal 180 */ 181 enum EDontAdopt { 182 kDontAdopt 183 }; 184 185 /** 186 * Constructor from a flattened set of RBBI data in malloced memory. 187 * RulesBasedBreakIterators built from a custom set of rules 188 * are created via this constructor; the rules are compiled 189 * into memory, then the break iterator is constructed here. 190 * 191 * The break iterator adopts the memory, and will 192 * free it when done. 193 * @internal 194 */ 195 RuleBasedBreakIterator(RBBIDataHeader* data, UErrorCode &status); 196 197 /** 198 * Constructor from a flattened set of RBBI data in memory which need not 199 * be malloced (e.g. it may be a memory-mapped file, etc.). 200 * 201 * This version does not adopt the memory, and does not 202 * free it when done. 203 * @internal 204 */ 205 RuleBasedBreakIterator(const RBBIDataHeader* data, enum EDontAdopt dontAdopt, UErrorCode &status); 206 207 208 friend class RBBIRuleBuilder; 209 /** @internal */ 210 friend class BreakIterator; 211 212 213 214 public: 215 216 /** Default constructor. Creates an empty shell of an iterator, with no 217 * rules or text to iterate over. Object can subsequently be assigned to. 218 * @stable ICU 2.2 219 */ 220 RuleBasedBreakIterator(); 221 222 /** 223 * Copy constructor. Will produce a break iterator with the same behavior, 224 * and which iterates over the same text, as the one passed in. 225 * @param that The RuleBasedBreakIterator passed to be copied 226 * @stable ICU 2.0 227 */ 228 RuleBasedBreakIterator(const RuleBasedBreakIterator& that); 229 230 /** 231 * Construct a RuleBasedBreakIterator from a set of rules supplied as a string. 232 * @param rules The break rules to be used. 233 * @param parseError In the event of a syntax error in the rules, provides the location 234 * within the rules of the problem. 235 * @param status Information on any errors encountered. 236 * @stable ICU 2.2 237 */ 238 RuleBasedBreakIterator( const UnicodeString &rules, 239 UParseError &parseError, 240 UErrorCode &status); 241 242 243 /** 244 * This constructor uses the udata interface to create a BreakIterator 245 * whose internal tables live in a memory-mapped file. "image" is an 246 * ICU UDataMemory handle for the pre-compiled break iterator tables. 247 * @param image handle to the memory image for the break iterator data. 248 * Ownership of the UDataMemory handle passes to the Break Iterator, 249 * which will be responsible for closing it when it is no longer needed. 250 * @param status Information on any errors encountered. 251 * @see udata_open 252 * @see #getBinaryRules 253 * @stable ICU 2.8 254 */ 255 RuleBasedBreakIterator(UDataMemory* image, UErrorCode &status); 256 257 /** 258 * Destructor 259 * @stable ICU 2.0 260 */ 261 virtual ~RuleBasedBreakIterator(); 262 263 /** 264 * Assignment operator. Sets this iterator to have the same behavior, 265 * and iterate over the same text, as the one passed in. 266 * @param that The RuleBasedBreakItertor passed in 267 * @return the newly created RuleBasedBreakIterator 268 * @stable ICU 2.0 269 */ 270 RuleBasedBreakIterator& operator=(const RuleBasedBreakIterator& that); 271 272 /** 273 * Equality operator. Returns TRUE if both BreakIterators are of the 274 * same class, have the same behavior, and iterate over the same text. 275 * @param that The BreakIterator to be compared for equality 276 * @return TRUE if both BreakIterators are of the 277 * same class, have the same behavior, and iterate over the same text. 278 * @stable ICU 2.0 279 */ 280 virtual UBool operator==(const BreakIterator& that) const; 281 282 /** 283 * Not-equal operator. If operator== returns TRUE, this returns FALSE, 284 * and vice versa. 285 * @param that The BreakIterator to be compared for inequality 286 * @return TRUE if both BreakIterators are not same. 287 * @stable ICU 2.0 288 */ 289 UBool operator!=(const BreakIterator& that) const; 290 291 /** 292 * Returns a newly-constructed RuleBasedBreakIterator with the same 293 * behavior, and iterating over the same text, as this one. 294 * Differs from the copy constructor in that it is polymorphic, and 295 * will correctly clone (copy) a derived class. 296 * clone() is thread safe. Multiple threads may simultaeneously 297 * clone the same source break iterator. 298 * @return a newly-constructed RuleBasedBreakIterator 299 * @stable ICU 2.0 300 */ 301 virtual BreakIterator* clone() const; 302 303 /** 304 * Compute a hash code for this BreakIterator 305 * @return A hash code 306 * @stable ICU 2.0 307 */ 308 virtual int32_t hashCode(void) const; 309 310 /** 311 * Returns the description used to create this iterator 312 * @return the description used to create this iterator 313 * @stable ICU 2.0 314 */ 315 virtual const UnicodeString& getRules(void) const; 316 317 //======================================================================= 318 // BreakIterator overrides 319 //======================================================================= 320 321 /** 322 * <p> 323 * Return a CharacterIterator over the text being analyzed. 324 * The returned character iterator is owned by the break iterator, and must 325 * not be deleted by the caller. Repeated calls to this function may 326 * return the same CharacterIterator. 327 * </p> 328 * <p> 329 * The returned character iterator must not be used concurrently with 330 * the break iterator. If concurrent operation is needed, clone the 331 * returned character iterator first and operate on the clone. 332 * </p> 333 * <p> 334 * When the break iterator is operating on text supplied via a UText, 335 * this function will fail. Lacking any way to signal failures, it 336 * returns an CharacterIterator containing no text. 337 * The function getUText() provides similar functionality, 338 * is reliable, and is more efficient. 339 * </p> 340 * 341 * TODO: deprecate this function? 342 * 343 * @return An iterator over the text being analyzed. 344 * @stable ICU 2.0 345 */ 346 virtual CharacterIterator& getText(void) const; 347 348 349 /** 350 * Get a UText for the text being analyzed. 351 * The returned UText is a shallow clone of the UText used internally 352 * by the break iterator implementation. It can safely be used to 353 * access the text without impacting any break iterator operations, 354 * but the underlying text itself must not be altered. 355 * 356 * @param fillIn A UText to be filled in. If NULL, a new UText will be 357 * allocated to hold the result. 358 * @param status receives any error codes. 359 * @return The current UText for this break iterator. If an input 360 * UText was provided, it will always be returned. 361 * @stable ICU 3.4 362 */ 363 virtual UText *getUText(UText *fillIn, UErrorCode &status) const; 364 365 /** 366 * Set the iterator to analyze a new piece of text. This function resets 367 * the current iteration position to the beginning of the text. 368 * @param newText An iterator over the text to analyze. The BreakIterator 369 * takes ownership of the character iterator. The caller MUST NOT delete it! 370 * @stable ICU 2.0 371 */ 372 virtual void adoptText(CharacterIterator* newText); 373 374 /** 375 * Set the iterator to analyze a new piece of text. This function resets 376 * the current iteration position to the beginning of the text. 377 * @param newText The text to analyze. 378 * @stable ICU 2.0 379 */ 380 virtual void setText(const UnicodeString& newText); 381 382 /** 383 * Reset the break iterator to operate over the text represented by 384 * the UText. The iterator position is reset to the start. 385 * 386 * This function makes a shallow clone of the supplied UText. This means 387 * that the caller is free to immediately close or otherwise reuse the 388 * Utext that was passed as a parameter, but that the underlying text itself 389 * must not be altered while being referenced by the break iterator. 390 * 391 * @param text The UText used to change the text. 392 * @param status Receives any error codes. 393 * @stable ICU 3.4 394 */ 395 virtual void setText(UText *text, UErrorCode &status); 396 397 /** 398 * Sets the current iteration position to the beginning of the text. 399 * @return The offset of the beginning of the text. 400 * @stable ICU 2.0 401 */ 402 virtual int32_t first(void); 403 404 /** 405 * Sets the current iteration position to the end of the text. 406 * @return The text's past-the-end offset. 407 * @stable ICU 2.0 408 */ 409 virtual int32_t last(void); 410 411 /** 412 * Advances the iterator either forward or backward the specified number of steps. 413 * Negative values move backward, and positive values move forward. This is 414 * equivalent to repeatedly calling next() or previous(). 415 * @param n The number of steps to move. The sign indicates the direction 416 * (negative is backwards, and positive is forwards). 417 * @return The character offset of the boundary position n boundaries away from 418 * the current one. 419 * @stable ICU 2.0 420 */ 421 virtual int32_t next(int32_t n); 422 423 /** 424 * Advances the iterator to the next boundary position. 425 * @return The position of the first boundary after this one. 426 * @stable ICU 2.0 427 */ 428 virtual int32_t next(void); 429 430 /** 431 * Moves the iterator backwards, to the last boundary preceding this one. 432 * @return The position of the last boundary position preceding this one. 433 * @stable ICU 2.0 434 */ 435 virtual int32_t previous(void); 436 437 /** 438 * Sets the iterator to refer to the first boundary position following 439 * the specified position. 440 * @param offset The position from which to begin searching for a break position. 441 * @return The position of the first break after the current position. 442 * @stable ICU 2.0 443 */ 444 virtual int32_t following(int32_t offset); 445 446 /** 447 * Sets the iterator to refer to the last boundary position before the 448 * specified position. 449 * @param offset The position to begin searching for a break from. 450 * @return The position of the last boundary before the starting position. 451 * @stable ICU 2.0 452 */ 453 virtual int32_t preceding(int32_t offset); 454 455 /** 456 * Returns true if the specfied position is a boundary position. As a side 457 * effect, leaves the iterator pointing to the first boundary position at 458 * or after "offset". 459 * @param offset the offset to check. 460 * @return True if "offset" is a boundary position. 461 * @stable ICU 2.0 462 */ 463 virtual UBool isBoundary(int32_t offset); 464 465 /** 466 * Returns the current iteration position. 467 * @return The current iteration position. 468 * @stable ICU 2.0 469 */ 470 virtual int32_t current(void) const; 471 472 473 /** 474 * Return the status tag from the break rule that determined the most recently 475 * returned break position. For break rules that do not specify a 476 * status, a default value of 0 is returned. If more than one break rule 477 * would cause a boundary to be located at some position in the text, 478 * the numerically largest of the applicable status values is returned. 479 * <p> 480 * Of the standard types of ICU break iterators, only word break and 481 * line break provide status values. The values are defined in 482 * the header file ubrk.h. For Word breaks, the status allows distinguishing between words 483 * that contain alphabetic letters, "words" that appear to be numbers, 484 * punctuation and spaces, words containing ideographic characters, and 485 * more. For Line Break, the status distinguishes between hard (mandatory) breaks 486 * and soft (potential) break positions. 487 * <p> 488 * <code>getRuleStatus()</code> can be called after obtaining a boundary 489 * position from <code>next()</code>, <code>previous()</code>, or 490 * any other break iterator functions that returns a boundary position. 491 * <p> 492 * When creating custom break rules, one is free to define whatever 493 * status values may be convenient for the application. 494 * <p> 495 * Note: this function is not thread safe. It should not have been 496 * declared const, and the const remains only for compatibility 497 * reasons. (The function is logically const, but not bit-wise const). 498 * <p> 499 * @return the status from the break rule that determined the most recently 500 * returned break position. 501 * 502 * @see UWordBreak 503 * @stable ICU 2.2 504 */ 505 virtual int32_t getRuleStatus() const; 506 507 /** 508 * Get the status (tag) values from the break rule(s) that determined the most 509 * recently returned break position. 510 * <p> 511 * The returned status value(s) are stored into an array provided by the caller. 512 * The values are stored in sorted (ascending) order. 513 * If the capacity of the output array is insufficient to hold the data, 514 * the output will be truncated to the available length, and a 515 * U_BUFFER_OVERFLOW_ERROR will be signaled. 516 * 517 * @param fillInVec an array to be filled in with the status values. 518 * @param capacity the length of the supplied vector. A length of zero causes 519 * the function to return the number of status values, in the 520 * normal way, without attemtping to store any values. 521 * @param status receives error codes. 522 * @return The number of rule status values from rules that determined 523 * the most recent boundary returned by the break iterator. 524 * In the event of a U_BUFFER_OVERFLOW_ERROR, the return value 525 * is the total number of status values that were available, 526 * not the reduced number that were actually returned. 527 * @see getRuleStatus 528 * @stable ICU 3.0 529 */ 530 virtual int32_t getRuleStatusVec(int32_t *fillInVec, int32_t capacity, UErrorCode &status); 531 532 /** 533 * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. 534 * This method is to implement a simple version of RTTI, since not all 535 * C++ compilers support genuine RTTI. Polymorphic operator==() and 536 * clone() methods call this method. 537 * 538 * @return The class ID for this object. All objects of a 539 * given class have the same class ID. Objects of 540 * other classes have different class IDs. 541 * @stable ICU 2.0 542 */ 543 virtual UClassID getDynamicClassID(void) const; 544 545 /** 546 * Returns the class ID for this class. This is useful only for 547 * comparing to a return value from getDynamicClassID(). For example: 548 * 549 * Base* polymorphic_pointer = createPolymorphicObject(); 550 * if (polymorphic_pointer->getDynamicClassID() == 551 * Derived::getStaticClassID()) ... 552 * 553 * @return The class ID for all objects of this class. 554 * @stable ICU 2.0 555 */ 556 static UClassID U_EXPORT2 getStaticClassID(void); 557 558 /* 559 * Create a clone (copy) of this break iterator in memory provided 560 * by the caller. The idea is to increase performance by avoiding 561 * a storage allocation. Use of this functoin is NOT RECOMMENDED. 562 * Performance gains are minimal, and correct buffer management is 563 * tricky. Use clone() instead. 564 * 565 * @param stackBuffer The pointer to the memory into which the cloned object 566 * should be placed. If NULL, allocate heap memory 567 * for the cloned object. 568 * @param BufferSize The size of the buffer. If zero, return the required 569 * buffer size, but do not clone the object. If the 570 * size was too small (but not zero), allocate heap 571 * storage for the cloned object. 572 * 573 * @param status Error status. U_SAFECLONE_ALLOCATED_WARNING will be 574 * returned if the the provided buffer was too small, and 575 * the clone was therefore put on the heap. 576 * 577 * @return Pointer to the clone object. This may differ from the stackBuffer 578 * address if the byte alignment of the stack buffer was not suitable 579 * or if the stackBuffer was too small to hold the clone. 580 * @stable ICU 2.0 581 */ 582 virtual BreakIterator * createBufferClone(void *stackBuffer, 583 int32_t &BufferSize, 584 UErrorCode &status); 585 586 587 /** 588 * Return the binary form of compiled break rules, 589 * which can then be used to create a new break iterator at some 590 * time in the future. Creating a break iterator from pre-compiled rules 591 * is much faster than building one from the source form of the 592 * break rules. 593 * 594 * The binary data can only be used with the same version of ICU 595 * and on the same platform type (processor endian-ness) 596 * 597 * @param length Returns the length of the binary data. (Out paramter.) 598 * 599 * @return A pointer to the binary (compiled) rule data. The storage 600 * belongs to the RulesBasedBreakIterator object, not the 601 * caller, and must not be modified or deleted. 602 * @internal 603 */ 604 virtual const uint8_t *getBinaryRules(uint32_t &length); 605 606 607 protected: 608 //======================================================================= 609 // implementation 610 //======================================================================= 611 /** 612 * Dumps caches and performs other actions associated with a complete change 613 * in text or iteration position. 614 * @internal 615 */ 616 virtual void reset(void); 617 618 #if 0 619 /** 620 * Return true if the category lookup for this char 621 * indicates that it is in the set of dictionary lookup chars. 622 * This function is intended for use by dictionary based break iterators. 623 * @return true if the category lookup for this char 624 * indicates that it is in the set of dictionary lookup chars. 625 * @internal 626 */ 627 virtual UBool isDictionaryChar(UChar32); 628 629 /** 630 * Get the type of the break iterator. 631 * @internal 632 */ 633 virtual int32_t getBreakType() const; 634 #endif 635 636 /** 637 * Set the type of the break iterator. 638 * @internal 639 */ 640 virtual void setBreakType(int32_t type); 641 642 /** 643 * Common initialization function, used by constructors and bufferClone. 644 * (Also used by DictionaryBasedBreakIterator::createBufferClone().) 645 * @internal 646 */ 647 void init(); 648 649 private: 650 651 /** 652 * This method backs the iterator back up to a "safe position" in the text. 653 * This is a position that we know, without any context, must be a break position. 654 * The various calling methods then iterate forward from this safe position to 655 * the appropriate position to return. (For more information, see the description 656 * of buildBackwardsStateTable() in RuleBasedBreakIterator.Builder.) 657 * @param statetable state table used of moving backwards 658 * @internal 659 */ 660 int32_t handlePrevious(const RBBIStateTable *statetable); 661 662 /** 663 * This method is the actual implementation of the next() method. All iteration 664 * vectors through here. This method initializes the state machine to state 1 665 * and advances through the text character by character until we reach the end 666 * of the text or the state machine transitions to state 0. We update our return 667 * value every time the state machine passes through a possible end state. 668 * @param statetable state table used of moving forwards 669 * @internal 670 */ 671 int32_t handleNext(const RBBIStateTable *statetable); 672 673 protected: 674 675 /** 676 * This is the function that actually implements dictionary-based 677 * breaking. Covering at least the range from startPos to endPos, 678 * it checks for dictionary characters, and if it finds them determines 679 * the appropriate object to deal with them. It may cache found breaks in 680 * fCachedBreakPositions as it goes. It may well also look at text outside 681 * the range startPos to endPos. 682 * If going forward, endPos is the normal Unicode break result, and 683 * if goind in reverse, startPos is the normal Unicode break result 684 * @param startPos The start position of a range of text 685 * @param endPos The end position of a range of text 686 * @param reverse The call is for the reverse direction 687 * @internal 688 */ 689 int32_t checkDictionary(int32_t startPos, int32_t endPos, UBool reverse); 690 691 private: 692 693 /** 694 * This function returns the appropriate LanguageBreakEngine for a 695 * given character c. 696 * @param c A character in the dictionary set 697 * @internal 698 */ 699 const LanguageBreakEngine *getLanguageBreakEngine(UChar32 c); 700 701 /** 702 * @internal 703 */ 704 void makeRuleStatusValid(); 705 706 }; 707 708 //------------------------------------------------------------------------------ 709 // 710 // Inline Functions Definitions ... 711 // 712 //------------------------------------------------------------------------------ 713 714 inline UBool RuleBasedBreakIterator::operator!=(const BreakIterator& that) const { 715 return !operator==(that); 716 } 717 718 U_NAMESPACE_END 719 720 #endif /* #if !UCONFIG_NO_BREAK_ITERATION */ 721 722 #endif 723
