1 /* 2 ********************************************************************** 3 * Copyright (C) 2001-2010 IBM and others. All rights reserved. 4 ********************************************************************** 5 * Date Name Description 6 * 06/28/2001 synwee Creation. 7 ********************************************************************** 8 */ 9 #ifndef USEARCH_H 10 #define USEARCH_H 11 12 #include "unicode/utypes.h" 13 14 #if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION 15 16 #include "unicode/localpointer.h" 17 #include "unicode/ucol.h" 18 #include "unicode/ucoleitr.h" 19 #include "unicode/ubrk.h" 20 21 /** 22 * \file 23 * \brief C API: StringSearch 24 * 25 * C Apis for an engine that provides language-sensitive text searching based 26 * on the comparison rules defined in a <tt>UCollator</tt> data struct, 27 * see <tt>ucol.h</tt>. This ensures that language eccentricity can be 28 * handled, e.g. for the German collator, characters ß and SS will be matched 29 * if case is chosen to be ignored. 30 * See the <a href="http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm"> 31 * "ICU Collation Design Document"</a> for more information. 32 * <p> 33 * The algorithm implemented is a modified form of the Boyer Moore's search. 34 * For more information see 35 * <a href="http://icu-project.org/docs/papers/efficient_text_searching_in_java.html"> 36 * "Efficient Text Searching in Java"</a>, published in <i>Java Report</i> 37 * in February, 1999, for further information on the algorithm. 38 * <p> 39 * There are 2 match options for selection:<br> 40 * Let S' be the sub-string of a text string S between the offsets start and 41 * end <start, end>. 42 * <br> 43 * A pattern string P matches a text string S at the offsets <start, end> 44 * if 45 * <pre> 46 * option 1. Some canonical equivalent of P matches some canonical equivalent 47 * of S' 48 * option 2. P matches S' and if P starts or ends with a combining mark, 49 * there exists no non-ignorable combining mark before or after S' 50 * in S respectively. 51 * </pre> 52 * Option 2. will be the default. 53 * <p> 54 * This search has APIs similar to that of other text iteration mechanisms 55 * such as the break iterators in <tt>ubrk.h</tt>. Using these 56 * APIs, it is easy to scan through text looking for all occurances of 57 * a given pattern. This search iterator allows changing of direction by 58 * calling a <tt>reset</tt> followed by a <tt>next</tt> or <tt>previous</tt>. 59 * Though a direction change can occur without calling <tt>reset</tt> first, 60 * this operation comes with some speed penalty. 61 * Generally, match results in the forward direction will match the result 62 * matches in the backwards direction in the reverse order 63 * <p> 64 * <tt>usearch.h</tt> provides APIs to specify the starting position 65 * within the text string to be searched, e.g. <tt>usearch_setOffset</tt>, 66 * <tt>usearch_preceding</tt> and <tt>usearch_following</tt>. Since the 67 * starting position will be set as it is specified, please take note that 68 * there are some dangerous positions which the search may render incorrect 69 * results: 70 * <ul> 71 * <li> The midst of a substring that requires normalization. 72 * <li> If the following match is to be found, the position should not be the 73 * second character which requires to be swapped with the preceding 74 * character. Vice versa, if the preceding match is to be found, 75 * position to search from should not be the first character which 76 * requires to be swapped with the next character. E.g certain Thai and 77 * Lao characters require swapping. 78 * <li> If a following pattern match is to be found, any position within a 79 * contracting sequence except the first will fail. Vice versa if a 80 * preceding pattern match is to be found, a invalid starting point 81 * would be any character within a contracting sequence except the last. 82 * </ul> 83 * <p> 84 * A breakiterator can be used if only matches at logical breaks are desired. 85 * Using a breakiterator will only give you results that exactly matches the 86 * boundaries given by the breakiterator. For instance the pattern "e" will 87 * not be found in the string "\u00e9" if a character break iterator is used. 88 * <p> 89 * Options are provided to handle overlapping matches. 90 * E.g. In English, overlapping matches produces the result 0 and 2 91 * for the pattern "abab" in the text "ababab", where else mutually 92 * exclusive matches only produce the result of 0. 93 * <p> 94 * Though collator attributes will be taken into consideration while 95 * performing matches, there are no APIs here for setting and getting the 96 * attributes. These attributes can be set by getting the collator 97 * from <tt>usearch_getCollator</tt> and using the APIs in <tt>ucol.h</tt>. 98 * Lastly to update String Search to the new collator attributes, 99 * usearch_reset() has to be called. 100 * <p> 101 * Restriction: <br> 102 * Currently there are no composite characters that consists of a 103 * character with combining class > 0 before a character with combining 104 * class == 0. However, if such a character exists in the future, the 105 * search mechanism does not guarantee the results for option 1. 106 * 107 * <p> 108 * Example of use:<br> 109 * <pre><code> 110 * char *tgtstr = "The quick brown fox jumped over the lazy fox"; 111 * char *patstr = "fox"; 112 * UChar target[64]; 113 * UChar pattern[16]; 114 * UErrorCode status = U_ZERO_ERROR; 115 * u_uastrcpy(target, tgtstr); 116 * u_uastrcpy(pattern, patstr); 117 * 118 * UStringSearch *search = usearch_open(pattern, -1, target, -1, "en_US", 119 * NULL, &status); 120 * if (U_SUCCESS(status)) { 121 * for (int pos = usearch_first(search, &status); 122 * pos != USEARCH_DONE; 123 * pos = usearch_next(search, &status)) 124 * { 125 * printf("Found match at %d pos, length is %d\n", pos, 126 * usearch_getMatchLength(search)); 127 * } 128 * } 129 * 130 * usearch_close(search); 131 * </code></pre> 132 * @stable ICU 2.4 133 */ 134 135 /** 136 * DONE is returned by previous() and next() after all valid matches have 137 * been returned, and by first() and last() if there are no matches at all. 138 * @stable ICU 2.4 139 */ 140 #define USEARCH_DONE -1 141 142 /** 143 * Data structure for searching 144 * @stable ICU 2.4 145 */ 146 struct UStringSearch; 147 /** 148 * Data structure for searching 149 * @stable ICU 2.4 150 */ 151 typedef struct UStringSearch UStringSearch; 152 153 /** 154 * @stable ICU 2.4 155 */ 156 typedef enum { 157 /** Option for overlapping matches */ 158 USEARCH_OVERLAP, 159 /** 160 * Option for canonical matches. option 1 in header documentation. 161 * The default value will be USEARCH_OFF 162 */ 163 USEARCH_CANONICAL_MATCH, 164 /** 165 * Option to control how collation elements are compared. 166 * The default value will be USEARCH_STANDARD_ELEMENT_COMPARISON. 167 * @stable ICU 4.4 168 */ 169 USEARCH_ELEMENT_COMPARISON, 170 171 USEARCH_ATTRIBUTE_COUNT 172 } USearchAttribute; 173 174 /** 175 * @stable ICU 2.4 176 */ 177 typedef enum { 178 /** Default value for any USearchAttribute */ 179 USEARCH_DEFAULT = -1, 180 /** Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH */ 181 USEARCH_OFF, 182 /** Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH */ 183 USEARCH_ON, 184 /** 185 * Value (default) for USEARCH_ELEMENT_COMPARISON; 186 * standard collation element comparison at the specified collator 187 * strength. 188 * @stable ICU 4.4 189 */ 190 USEARCH_STANDARD_ELEMENT_COMPARISON, 191 /** 192 * Value for USEARCH_ELEMENT_COMPARISON; 193 * collation element comparison is modified to effectively provide 194 * behavior between the specified strength and strength - 1. Collation 195 * elements in the pattern that have the base weight for the specified 196 * strength are treated as "wildcards" that match an element with any 197 * other weight at that collation level in the searched text. For 198 * example, with a secondary-strength English collator, a plain 'e' in 199 * the pattern will match a plain e or an e with any diacritic in the 200 * searched text, but an e with diacritic in the pattern will only 201 * match an e with the same diacritic in the searched text. 202 * @stable ICU 4.4 203 */ 204 USEARCH_PATTERN_BASE_WEIGHT_IS_WILDCARD, 205 /** 206 * Value for USEARCH_ELEMENT_COMPARISON. 207 * collation element comparison is modified to effectively provide 208 * behavior between the specified strength and strength - 1. Collation 209 * elements in either the pattern or the searched text that have the 210 * base weight for the specified strength are treated as "wildcards" 211 * that match an element with any other weight at that collation level. 212 * For example, with a secondary-strength English collator, a plain 'e' 213 * in the pattern will match a plain e or an e with any diacritic in the 214 * searched text, but an e with diacritic in the pattern will only 215 * match an e with the same diacritic or a plain e in the searched text. 216 * @stable ICU 4.4 217 */ 218 USEARCH_ANY_BASE_WEIGHT_IS_WILDCARD, 219 220 USEARCH_ATTRIBUTE_VALUE_COUNT 221 } USearchAttributeValue; 222 223 /* open and close ------------------------------------------------------ */ 224 225 /** 226 * Creating a search iterator data struct using the argument locale language 227 * rule set. A collator will be created in the process, which will be owned by 228 * this search and will be deleted in <tt>usearch_close</tt>. 229 * @param pattern for matching 230 * @param patternlength length of the pattern, -1 for null-termination 231 * @param text text string 232 * @param textlength length of the text string, -1 for null-termination 233 * @param locale name of locale for the rules to be used 234 * @param breakiter A BreakIterator that will be used to restrict the points 235 * at which matches are detected. If a match is found, but 236 * the match's start or end index is not a boundary as 237 * determined by the <tt>BreakIterator</tt>, the match will 238 * be rejected and another will be searched for. 239 * If this parameter is <tt>NULL</tt>, no break detection is 240 * attempted. 241 * @param status for errors if it occurs. If pattern or text is NULL, or if 242 * patternlength or textlength is 0 then an 243 * U_ILLEGAL_ARGUMENT_ERROR is returned. 244 * @return search iterator data structure, or NULL if there is an error. 245 * @stable ICU 2.4 246 */ 247 U_STABLE UStringSearch * U_EXPORT2 usearch_open(const UChar *pattern, 248 int32_t patternlength, 249 const UChar *text, 250 int32_t textlength, 251 const char *locale, 252 UBreakIterator *breakiter, 253 UErrorCode *status); 254 255 /** 256 * Creating a search iterator data struct using the argument collator language 257 * rule set. Note, user retains the ownership of this collator, thus the 258 * responsibility of deletion lies with the user. 259 * NOTE: string search cannot be instantiated from a collator that has 260 * collate digits as numbers (CODAN) turned on. 261 * @param pattern for matching 262 * @param patternlength length of the pattern, -1 for null-termination 263 * @param text text string 264 * @param textlength length of the text string, -1 for null-termination 265 * @param collator used for the language rules 266 * @param breakiter A BreakIterator that will be used to restrict the points 267 * at which matches are detected. If a match is found, but 268 * the match's start or end index is not a boundary as 269 * determined by the <tt>BreakIterator</tt>, the match will 270 * be rejected and another will be searched for. 271 * If this parameter is <tt>NULL</tt>, no break detection is 272 * attempted. 273 * @param status for errors if it occurs. If collator, pattern or text is NULL, 274 * or if patternlength or textlength is 0 then an 275 * U_ILLEGAL_ARGUMENT_ERROR is returned. 276 * @return search iterator data structure, or NULL if there is an error. 277 * @stable ICU 2.4 278 */ 279 U_STABLE UStringSearch * U_EXPORT2 usearch_openFromCollator( 280 const UChar *pattern, 281 int32_t patternlength, 282 const UChar *text, 283 int32_t textlength, 284 const UCollator *collator, 285 UBreakIterator *breakiter, 286 UErrorCode *status); 287 288 /** 289 * Destroying and cleaning up the search iterator data struct. 290 * If a collator is created in <tt>usearch_open</tt>, it will be destroyed here. 291 * @param searchiter data struct to clean up 292 * @stable ICU 2.4 293 */ 294 U_STABLE void U_EXPORT2 usearch_close(UStringSearch *searchiter); 295 296 #if U_SHOW_CPLUSPLUS_API 297 298 U_NAMESPACE_BEGIN 299 300 /** 301 * \class LocalUStringSearchPointer 302 * "Smart pointer" class, closes a UStringSearch via usearch_close(). 303 * For most methods see the LocalPointerBase base class. 304 * 305 * @see LocalPointerBase 306 * @see LocalPointer 307 * @stable ICU 4.4 308 */ 309 U_DEFINE_LOCAL_OPEN_POINTER(LocalUStringSearchPointer, UStringSearch, usearch_close); 310 311 U_NAMESPACE_END 312 313 #endif 314 315 /* get and set methods -------------------------------------------------- */ 316 317 /** 318 * Sets the current position in the text string which the next search will 319 * start from. Clears previous states. 320 * This method takes the argument index and sets the position in the text 321 * string accordingly without checking if the index is pointing to a 322 * valid starting point to begin searching. 323 * Search positions that may render incorrect results are highlighted in the 324 * header comments 325 * @param strsrch search iterator data struct 326 * @param position position to start next search from. If position is less 327 * than or greater than the text range for searching, 328 * an U_INDEX_OUTOFBOUNDS_ERROR will be returned 329 * @param status error status if any. 330 * @stable ICU 2.4 331 */ 332 U_STABLE void U_EXPORT2 usearch_setOffset(UStringSearch *strsrch, 333 int32_t position, 334 UErrorCode *status); 335 336 /** 337 * Return the current index in the string text being searched. 338 * If the iteration has gone past the end of the text (or past the beginning 339 * for a backwards search), <tt>USEARCH_DONE</tt> is returned. 340 * @param strsrch search iterator data struct 341 * @see #USEARCH_DONE 342 * @stable ICU 2.4 343 */ 344 U_STABLE int32_t U_EXPORT2 usearch_getOffset(const UStringSearch *strsrch); 345 346 /** 347 * Sets the text searching attributes located in the enum USearchAttribute 348 * with values from the enum USearchAttributeValue. 349 * <tt>USEARCH_DEFAULT</tt> can be used for all attributes for resetting. 350 * @param strsrch search iterator data struct 351 * @param attribute text attribute to be set 352 * @param value text attribute value 353 * @param status for errors if it occurs 354 * @see #usearch_getAttribute 355 * @stable ICU 2.4 356 */ 357 U_STABLE void U_EXPORT2 usearch_setAttribute(UStringSearch *strsrch, 358 USearchAttribute attribute, 359 USearchAttributeValue value, 360 UErrorCode *status); 361 362 /** 363 * Gets the text searching attributes. 364 * @param strsrch search iterator data struct 365 * @param attribute text attribute to be retrieve 366 * @return text attribute value 367 * @see #usearch_setAttribute 368 * @stable ICU 2.4 369 */ 370 U_STABLE USearchAttributeValue U_EXPORT2 usearch_getAttribute( 371 const UStringSearch *strsrch, 372 USearchAttribute attribute); 373 374 /** 375 * Returns the index to the match in the text string that was searched. 376 * This call returns a valid result only after a successful call to 377 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 378 * or <tt>usearch_last</tt>. 379 * Just after construction, or after a searching method returns 380 * <tt>USEARCH_DONE</tt>, this method will return <tt>USEARCH_DONE</tt>. 381 * <p> 382 * Use <tt>usearch_getMatchedLength</tt> to get the matched string length. 383 * @param strsrch search iterator data struct 384 * @return index to a substring within the text string that is being 385 * searched. 386 * @see #usearch_first 387 * @see #usearch_next 388 * @see #usearch_previous 389 * @see #usearch_last 390 * @see #USEARCH_DONE 391 * @stable ICU 2.4 392 */ 393 U_STABLE int32_t U_EXPORT2 usearch_getMatchedStart( 394 const UStringSearch *strsrch); 395 396 /** 397 * Returns the length of text in the string which matches the search pattern. 398 * This call returns a valid result only after a successful call to 399 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 400 * or <tt>usearch_last</tt>. 401 * Just after construction, or after a searching method returns 402 * <tt>USEARCH_DONE</tt>, this method will return 0. 403 * @param strsrch search iterator data struct 404 * @return The length of the match in the string text, or 0 if there is no 405 * match currently. 406 * @see #usearch_first 407 * @see #usearch_next 408 * @see #usearch_previous 409 * @see #usearch_last 410 * @see #USEARCH_DONE 411 * @stable ICU 2.4 412 */ 413 U_STABLE int32_t U_EXPORT2 usearch_getMatchedLength( 414 const UStringSearch *strsrch); 415 416 /** 417 * Returns the text that was matched by the most recent call to 418 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 419 * or <tt>usearch_last</tt>. 420 * If the iterator is not pointing at a valid match (e.g. just after 421 * construction or after <tt>USEARCH_DONE</tt> has been returned, returns 422 * an empty string. If result is not large enough to store the matched text, 423 * result will be filled with the partial text and an U_BUFFER_OVERFLOW_ERROR 424 * will be returned in status. result will be null-terminated whenever 425 * possible. If the buffer fits the matched text exactly, a null-termination 426 * is not possible, then a U_STRING_NOT_TERMINATED_ERROR set in status. 427 * Pre-flighting can be either done with length = 0 or the API 428 * <tt>usearch_getMatchLength</tt>. 429 * @param strsrch search iterator data struct 430 * @param result UChar buffer to store the matched string 431 * @param resultCapacity length of the result buffer 432 * @param status error returned if result is not large enough 433 * @return exact length of the matched text, not counting the null-termination 434 * @see #usearch_first 435 * @see #usearch_next 436 * @see #usearch_previous 437 * @see #usearch_last 438 * @see #USEARCH_DONE 439 * @stable ICU 2.4 440 */ 441 U_STABLE int32_t U_EXPORT2 usearch_getMatchedText(const UStringSearch *strsrch, 442 UChar *result, 443 int32_t resultCapacity, 444 UErrorCode *status); 445 446 #if !UCONFIG_NO_BREAK_ITERATION 447 448 /** 449 * Set the BreakIterator that will be used to restrict the points at which 450 * matches are detected. 451 * @param strsrch search iterator data struct 452 * @param breakiter A BreakIterator that will be used to restrict the points 453 * at which matches are detected. If a match is found, but 454 * the match's start or end index is not a boundary as 455 * determined by the <tt>BreakIterator</tt>, the match will 456 * be rejected and another will be searched for. 457 * If this parameter is <tt>NULL</tt>, no break detection is 458 * attempted. 459 * @param status for errors if it occurs 460 * @see #usearch_getBreakIterator 461 * @stable ICU 2.4 462 */ 463 U_STABLE void U_EXPORT2 usearch_setBreakIterator(UStringSearch *strsrch, 464 UBreakIterator *breakiter, 465 UErrorCode *status); 466 467 /** 468 * Returns the BreakIterator that is used to restrict the points at which 469 * matches are detected. This will be the same object that was passed to the 470 * constructor or to <tt>usearch_setBreakIterator</tt>. Note that 471 * <tt>NULL</tt> 472 * is a legal value; it means that break detection should not be attempted. 473 * @param strsrch search iterator data struct 474 * @return break iterator used 475 * @see #usearch_setBreakIterator 476 * @stable ICU 2.4 477 */ 478 U_STABLE const UBreakIterator * U_EXPORT2 usearch_getBreakIterator( 479 const UStringSearch *strsrch); 480 481 #endif 482 483 /** 484 * Set the string text to be searched. Text iteration will hence begin at the 485 * start of the text string. This method is useful if you want to re-use an 486 * iterator to search for the same pattern within a different body of text. 487 * @param strsrch search iterator data struct 488 * @param text new string to look for match 489 * @param textlength length of the new string, -1 for null-termination 490 * @param status for errors if it occurs. If text is NULL, or textlength is 0 491 * then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change 492 * done to strsrch. 493 * @see #usearch_getText 494 * @stable ICU 2.4 495 */ 496 U_STABLE void U_EXPORT2 usearch_setText( UStringSearch *strsrch, 497 const UChar *text, 498 int32_t textlength, 499 UErrorCode *status); 500 501 /** 502 * Return the string text to be searched. 503 * @param strsrch search iterator data struct 504 * @param length returned string text length 505 * @return string text 506 * @see #usearch_setText 507 * @stable ICU 2.4 508 */ 509 U_STABLE const UChar * U_EXPORT2 usearch_getText(const UStringSearch *strsrch, 510 int32_t *length); 511 512 /** 513 * Gets the collator used for the language rules. 514 * <p> 515 * Deleting the returned <tt>UCollator</tt> before calling 516 * <tt>usearch_close</tt> would cause the string search to fail. 517 * <tt>usearch_close</tt> will delete the collator if this search owns it. 518 * @param strsrch search iterator data struct 519 * @return collator 520 * @stable ICU 2.4 521 */ 522 U_STABLE UCollator * U_EXPORT2 usearch_getCollator( 523 const UStringSearch *strsrch); 524 525 /** 526 * Sets the collator used for the language rules. User retains the ownership 527 * of this collator, thus the responsibility of deletion lies with the user. 528 * This method causes internal data such as Boyer-Moore shift tables to 529 * be recalculated, but the iterator's position is unchanged. 530 * @param strsrch search iterator data struct 531 * @param collator to be used 532 * @param status for errors if it occurs 533 * @stable ICU 2.4 534 */ 535 U_STABLE void U_EXPORT2 usearch_setCollator( UStringSearch *strsrch, 536 const UCollator *collator, 537 UErrorCode *status); 538 539 /** 540 * Sets the pattern used for matching. 541 * Internal data like the Boyer Moore table will be recalculated, but the 542 * iterator's position is unchanged. 543 * @param strsrch search iterator data struct 544 * @param pattern string 545 * @param patternlength pattern length, -1 for null-terminated string 546 * @param status for errors if it occurs. If text is NULL, or textlength is 0 547 * then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change 548 * done to strsrch. 549 * @stable ICU 2.4 550 */ 551 U_STABLE void U_EXPORT2 usearch_setPattern( UStringSearch *strsrch, 552 const UChar *pattern, 553 int32_t patternlength, 554 UErrorCode *status); 555 556 /** 557 * Gets the search pattern 558 * @param strsrch search iterator data struct 559 * @param length return length of the pattern, -1 indicates that the pattern 560 * is null-terminated 561 * @return pattern string 562 * @stable ICU 2.4 563 */ 564 U_STABLE const UChar * U_EXPORT2 usearch_getPattern( 565 const UStringSearch *strsrch, 566 int32_t *length); 567 568 /* methods ------------------------------------------------------------- */ 569 570 /** 571 * Returns the first index at which the string text matches the search 572 * pattern. 573 * The iterator is adjusted so that its current index (as returned by 574 * <tt>usearch_getOffset</tt>) is the match position if one was found. 575 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 576 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>. 577 * @param strsrch search iterator data struct 578 * @param status for errors if it occurs 579 * @return The character index of the first match, or 580 * <tt>USEARCH_DONE</tt> if there are no matches. 581 * @see #usearch_getOffset 582 * @see #USEARCH_DONE 583 * @stable ICU 2.4 584 */ 585 U_STABLE int32_t U_EXPORT2 usearch_first(UStringSearch *strsrch, 586 UErrorCode *status); 587 588 /** 589 * Returns the first index greater than <tt>position</tt> at which the string 590 * text 591 * matches the search pattern. The iterator is adjusted so that its current 592 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 593 * one was found. 594 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 595 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 596 * <p> 597 * Search positions that may render incorrect results are highlighted in the 598 * header comments. If position is less than or greater than the text range 599 * for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned 600 * @param strsrch search iterator data struct 601 * @param position to start the search at 602 * @param status for errors if it occurs 603 * @return The character index of the first match following <tt>pos</tt>, 604 * or <tt>USEARCH_DONE</tt> if there are no matches. 605 * @see #usearch_getOffset 606 * @see #USEARCH_DONE 607 * @stable ICU 2.4 608 */ 609 U_STABLE int32_t U_EXPORT2 usearch_following(UStringSearch *strsrch, 610 int32_t position, 611 UErrorCode *status); 612 613 /** 614 * Returns the last index in the target text at which it matches the search 615 * pattern. The iterator is adjusted so that its current 616 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 617 * one was found. 618 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 619 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>. 620 * @param strsrch search iterator data struct 621 * @param status for errors if it occurs 622 * @return The index of the first match, or <tt>USEARCH_DONE</tt> if there 623 * are no matches. 624 * @see #usearch_getOffset 625 * @see #USEARCH_DONE 626 * @stable ICU 2.4 627 */ 628 U_STABLE int32_t U_EXPORT2 usearch_last(UStringSearch *strsrch, 629 UErrorCode *status); 630 631 /** 632 * Returns the first index less than <tt>position</tt> at which the string text 633 * matches the search pattern. The iterator is adjusted so that its current 634 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 635 * one was found. 636 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 637 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 638 * <p> 639 * Search positions that may render incorrect results are highlighted in the 640 * header comments. If position is less than or greater than the text range 641 * for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned 642 * @param strsrch search iterator data struct 643 * @param position index position the search is to begin at 644 * @param status for errors if it occurs 645 * @return The character index of the first match preceding <tt>pos</tt>, 646 * or <tt>USEARCH_DONE</tt> if there are no matches. 647 * @see #usearch_getOffset 648 * @see #USEARCH_DONE 649 * @stable ICU 2.4 650 */ 651 U_STABLE int32_t U_EXPORT2 usearch_preceding(UStringSearch *strsrch, 652 int32_t position, 653 UErrorCode *status); 654 655 /** 656 * Returns the index of the next point at which the string text matches the 657 * search pattern, starting from the current position. 658 * The iterator is adjusted so that its current 659 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 660 * one was found. 661 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 662 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 663 * @param strsrch search iterator data struct 664 * @param status for errors if it occurs 665 * @return The index of the next match after the current position, or 666 * <tt>USEARCH_DONE</tt> if there are no more matches. 667 * @see #usearch_first 668 * @see #usearch_getOffset 669 * @see #USEARCH_DONE 670 * @stable ICU 2.4 671 */ 672 U_STABLE int32_t U_EXPORT2 usearch_next(UStringSearch *strsrch, 673 UErrorCode *status); 674 675 /** 676 * Returns the index of the previous point at which the string text matches 677 * the search pattern, starting at the current position. 678 * The iterator is adjusted so that its current 679 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 680 * one was found. 681 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 682 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 683 * @param strsrch search iterator data struct 684 * @param status for errors if it occurs 685 * @return The index of the previous match before the current position, 686 * or <tt>USEARCH_DONE</tt> if there are no more matches. 687 * @see #usearch_last 688 * @see #usearch_getOffset 689 * @see #USEARCH_DONE 690 * @stable ICU 2.4 691 */ 692 U_STABLE int32_t U_EXPORT2 usearch_previous(UStringSearch *strsrch, 693 UErrorCode *status); 694 695 /** 696 * Reset the iteration. 697 * Search will begin at the start of the text string if a forward iteration 698 * is initiated before a backwards iteration. Otherwise if a backwards 699 * iteration is initiated before a forwards iteration, the search will begin 700 * at the end of the text string. 701 * @param strsrch search iterator data struct 702 * @see #usearch_first 703 * @stable ICU 2.4 704 */ 705 U_STABLE void U_EXPORT2 usearch_reset(UStringSearch *strsrch); 706 707 /** 708 * Simple forward search for the pattern, starting at a specified index, 709 * and using using a default set search options. 710 * 711 * This is an experimental function, and is not an official part of the 712 * ICU API. 713 * 714 * The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored. 715 * 716 * The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and 717 * any Break Iterator are ignored. 718 * 719 * Matches obey the following constraints: 720 * 721 * Characters at the start or end positions of a match that are ignorable 722 * for collation are not included as part of the match, unless they 723 * are part of a combining sequence, as described below. 724 * 725 * A match will not include a partial combining sequence. Combining 726 * character sequences are considered to be inseperable units, 727 * and either match the pattern completely, or are considered to not match 728 * at all. Thus, for example, an A followed a combining accent mark will 729 * not be found when searching for a plain (unaccented) A. (unless 730 * the collation strength has been set to ignore all accents). 731 * 732 * When beginning a search, the initial starting position, startIdx, 733 * is assumed to be an acceptable match boundary with respect to 734 * combining characters. A combining sequence that spans across the 735 * starting point will not supress a match beginning at startIdx. 736 * 737 * Characters that expand to multiple collation elements 738 * (German sharp-S becoming 'ss', or the composed forms of accented 739 * characters, for example) also must match completely. 740 * Searching for a single 's' in a string containing only a sharp-s will 741 * find no match. 742 * 743 * 744 * @param strsrch the UStringSearch struct, which references both 745 * the text to be searched and the pattern being sought. 746 * @param startIdx The index into the text to begin the search. 747 * @param matchStart An out parameter, the starting index of the matched text. 748 * This parameter may be NULL. 749 * A value of -1 will be returned if no match was found. 750 * @param matchLimit Out parameter, the index of the first position following the matched text. 751 * The matchLimit will be at a suitable position for beginning a subsequent search 752 * in the input text. 753 * This parameter may be NULL. 754 * A value of -1 will be returned if no match was found. 755 * 756 * @param status Report any errors. Note that no match found is not an error. 757 * @return TRUE if a match was found, FALSE otherwise. 758 * 759 * @internal 760 */ 761 U_INTERNAL UBool U_EXPORT2 usearch_search(UStringSearch *strsrch, 762 int32_t startIdx, 763 int32_t *matchStart, 764 int32_t *matchLimit, 765 UErrorCode *status); 766 767 /** 768 * Simple backwards search for the pattern, starting at a specified index, 769 * and using using a default set search options. 770 * 771 * This is an experimental function, and is not an official part of the 772 * ICU API. 773 * 774 * The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored. 775 * 776 * The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and 777 * any Break Iterator are ignored. 778 * 779 * Matches obey the following constraints: 780 * 781 * Characters at the start or end positions of a match that are ignorable 782 * for collation are not included as part of the match, unless they 783 * are part of a combining sequence, as described below. 784 * 785 * A match will not include a partial combining sequence. Combining 786 * character sequences are considered to be inseperable units, 787 * and either match the pattern completely, or are considered to not match 788 * at all. Thus, for example, an A followed a combining accent mark will 789 * not be found when searching for a plain (unaccented) A. (unless 790 * the collation strength has been set to ignore all accents). 791 * 792 * When beginning a search, the initial starting position, startIdx, 793 * is assumed to be an acceptable match boundary with respect to 794 * combining characters. A combining sequence that spans across the 795 * starting point will not supress a match beginning at startIdx. 796 * 797 * Characters that expand to multiple collation elements 798 * (German sharp-S becoming 'ss', or the composed forms of accented 799 * characters, for example) also must match completely. 800 * Searching for a single 's' in a string containing only a sharp-s will 801 * find no match. 802 * 803 * 804 * @param strsrch the UStringSearch struct, which references both 805 * the text to be searched and the pattern being sought. 806 * @param startIdx The index into the text to begin the search. 807 * @param matchStart An out parameter, the starting index of the matched text. 808 * This parameter may be NULL. 809 * A value of -1 will be returned if no match was found. 810 * @param matchLimit Out parameter, the index of the first position following the matched text. 811 * The matchLimit will be at a suitable position for beginning a subsequent search 812 * in the input text. 813 * This parameter may be NULL. 814 * A value of -1 will be returned if no match was found. 815 * 816 * @param status Report any errors. Note that no match found is not an error. 817 * @return TRUE if a match was found, FALSE otherwise. 818 * 819 * @internal 820 */ 821 U_INTERNAL UBool U_EXPORT2 usearch_searchBackwards(UStringSearch *strsrch, 822 int32_t startIdx, 823 int32_t *matchStart, 824 int32_t *matchLimit, 825 UErrorCode *status); 826 827 #endif /* #if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION */ 828 829 #endif 830