1// Copyright (C) 2016 and later: Unicode, Inc. and others. 2// License & terms of use: http://www.unicode.org/copyright.html 3/* 4********************************************************************** 5* Copyright (C) 2001-2011,2014 IBM and others. All rights reserved. 6********************************************************************** 7* Date Name Description 8* 06/28/2001 synwee Creation. 9********************************************************************** 10*/ 11#ifndef USEARCH_H 12#define USEARCH_H 13 14#include "unicode/utypes.h" 15 16#if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION 17 18#include "unicode/localpointer.h" 19#include "unicode/ucol.h" 20#include "unicode/ucoleitr.h" 21#include "unicode/ubrk.h" 22 23/** 24 * \file 25 * \brief C API: StringSearch 26 * 27 * C Apis for an engine that provides language-sensitive text searching based 28 * on the comparison rules defined in a <tt>UCollator</tt> data struct, 29 * see <tt>ucol.h</tt>. This ensures that language eccentricity can be 30 * handled, e.g. for the German collator, characters ß and SS will be matched 31 * if case is chosen to be ignored. 32 * See the <a href="http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm"> 33 * "ICU Collation Design Document"</a> for more information. 34 * <p> 35 * The implementation may use a linear search or a modified form of the Boyer-Moore 36 * search; for more information on the latter see 37 * <a href="http://icu-project.org/docs/papers/efficient_text_searching_in_java.html"> 38 * "Efficient Text Searching in Java"</a>, published in <i>Java Report</i> 39 * in February, 1999. 40 * <p> 41 * There are 2 match options for selection:<br> 42 * Let S' be the sub-string of a text string S between the offsets start and 43 * end <start, end>. 44 * <br> 45 * A pattern string P matches a text string S at the offsets <start, end> 46 * if 47 * <pre> 48 * option 1. Some canonical equivalent of P matches some canonical equivalent 49 * of S' 50 * option 2. P matches S' and if P starts or ends with a combining mark, 51 * there exists no non-ignorable combining mark before or after S' 52 * in S respectively. 53 * </pre> 54 * Option 2. will be the default. 55 * <p> 56 * This search has APIs similar to that of other text iteration mechanisms 57 * such as the break iterators in <tt>ubrk.h</tt>. Using these 58 * APIs, it is easy to scan through text looking for all occurances of 59 * a given pattern. This search iterator allows changing of direction by 60 * calling a <tt>reset</tt> followed by a <tt>next</tt> or <tt>previous</tt>. 61 * Though a direction change can occur without calling <tt>reset</tt> first, 62 * this operation comes with some speed penalty. 63 * Generally, match results in the forward direction will match the result 64 * matches in the backwards direction in the reverse order 65 * <p> 66 * <tt>usearch.h</tt> provides APIs to specify the starting position 67 * within the text string to be searched, e.g. <tt>usearch_setOffset</tt>, 68 * <tt>usearch_preceding</tt> and <tt>usearch_following</tt>. Since the 69 * starting position will be set as it is specified, please take note that 70 * there are some dangerous positions which the search may render incorrect 71 * results: 72 * <ul> 73 * <li> The midst of a substring that requires normalization. 74 * <li> If the following match is to be found, the position should not be the 75 * second character which requires to be swapped with the preceding 76 * character. Vice versa, if the preceding match is to be found, 77 * position to search from should not be the first character which 78 * requires to be swapped with the next character. E.g certain Thai and 79 * Lao characters require swapping. 80 * <li> If a following pattern match is to be found, any position within a 81 * contracting sequence except the first will fail. Vice versa if a 82 * preceding pattern match is to be found, a invalid starting point 83 * would be any character within a contracting sequence except the last. 84 * </ul> 85 * <p> 86 * A breakiterator can be used if only matches at logical breaks are desired. 87 * Using a breakiterator will only give you results that exactly matches the 88 * boundaries given by the breakiterator. For instance the pattern "e" will 89 * not be found in the string "\u00e9" if a character break iterator is used. 90 * <p> 91 * Options are provided to handle overlapping matches. 92 * E.g. In English, overlapping matches produces the result 0 and 2 93 * for the pattern "abab" in the text "ababab", where else mutually 94 * exclusive matches only produce the result of 0. 95 * <p> 96 * Options are also provided to implement "asymmetric search" as described in 97 * <a href="http://www.unicode.org/reports/tr10/#Asymmetric_Search"> 98 * UTS #10 Unicode Collation Algorithm</a>, specifically the USearchAttribute 99 * USEARCH_ELEMENT_COMPARISON and its values. 100 * <p> 101 * Though collator attributes will be taken into consideration while 102 * performing matches, there are no APIs here for setting and getting the 103 * attributes. These attributes can be set by getting the collator 104 * from <tt>usearch_getCollator</tt> and using the APIs in <tt>ucol.h</tt>. 105 * Lastly to update String Search to the new collator attributes, 106 * usearch_reset() has to be called. 107 * <p> 108 * Restriction: <br> 109 * Currently there are no composite characters that consists of a 110 * character with combining class > 0 before a character with combining 111 * class == 0. However, if such a character exists in the future, the 112 * search mechanism does not guarantee the results for option 1. 113 * 114 * <p> 115 * Example of use:<br> 116 * <pre><code> 117 * char *tgtstr = "The quick brown fox jumped over the lazy fox"; 118 * char *patstr = "fox"; 119 * UChar target[64]; 120 * UChar pattern[16]; 121 * UErrorCode status = U_ZERO_ERROR; 122 * u_uastrcpy(target, tgtstr); 123 * u_uastrcpy(pattern, patstr); 124 * 125 * UStringSearch *search = usearch_open(pattern, -1, target, -1, "en_US", 126 * NULL, &status); 127 * if (U_SUCCESS(status)) { 128 * for (int pos = usearch_first(search, &status); 129 * pos != USEARCH_DONE; 130 * pos = usearch_next(search, &status)) 131 * { 132 * printf("Found match at %d pos, length is %d\n", pos, 133 * usearch_getMatchLength(search)); 134 * } 135 * } 136 * 137 * usearch_close(search); 138 * </code></pre> 139 * @stable ICU 2.4 140 */ 141 142/** 143* DONE is returned by previous() and next() after all valid matches have 144* been returned, and by first() and last() if there are no matches at all. 145* @stable ICU 2.4 146*/ 147#define USEARCH_DONE -1 148 149/** 150* Data structure for searching 151* @stable ICU 2.4 152*/ 153struct UStringSearch; 154/** 155* Data structure for searching 156* @stable ICU 2.4 157*/ 158typedef struct UStringSearch UStringSearch; 159 160/** 161* @stable ICU 2.4 162*/ 163typedef enum { 164 /** 165 * Option for overlapping matches 166 * @stable ICU 2.4 167 */ 168 USEARCH_OVERLAP = 0, 169#ifndef U_HIDE_DEPRECATED_API 170 /** 171 * Option for canonical matches; option 1 in header documentation. 172 * The default value will be USEARCH_OFF. 173 * Note: Setting this option to USEARCH_ON currently has no effect on 174 * search behavior, and this option is deprecated. Instead, to control 175 * canonical match behavior, you must set UCOL_NORMALIZATION_MODE 176 * appropriately (to UCOL_OFF or UCOL_ON) in the UCollator used by 177 * the UStringSearch object. 178 * @see usearch_openFromCollator 179 * @see usearch_getCollator 180 * @see usearch_setCollator 181 * @see ucol_getAttribute 182 * @deprecated ICU 53 183 */ 184 USEARCH_CANONICAL_MATCH = 1, 185#endif /* U_HIDE_DEPRECATED_API */ 186 /** 187 * Option to control how collation elements are compared. 188 * The default value will be USEARCH_STANDARD_ELEMENT_COMPARISON. 189 * @stable ICU 4.4 190 */ 191 USEARCH_ELEMENT_COMPARISON = 2, 192 193#ifndef U_HIDE_DEPRECATED_API 194 /** 195 * One more than the highest normal USearchAttribute value. 196 * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420. 197 */ 198 USEARCH_ATTRIBUTE_COUNT = 3 199#endif // U_HIDE_DEPRECATED_API 200} USearchAttribute; 201 202/** 203* @stable ICU 2.4 204*/ 205typedef enum { 206 /** 207 * Default value for any USearchAttribute 208 * @stable ICU 2.4 209 */ 210 USEARCH_DEFAULT = -1, 211 /** 212 * Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH 213 * @stable ICU 2.4 214 */ 215 USEARCH_OFF, 216 /** 217 * Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH 218 * @stable ICU 2.4 219 */ 220 USEARCH_ON, 221 /** 222 * Value (default) for USEARCH_ELEMENT_COMPARISON; 223 * standard collation element comparison at the specified collator 224 * strength. 225 * @stable ICU 4.4 226 */ 227 USEARCH_STANDARD_ELEMENT_COMPARISON, 228 /** 229 * Value for USEARCH_ELEMENT_COMPARISON; 230 * collation element comparison is modified to effectively provide 231 * behavior between the specified strength and strength - 1. Collation 232 * elements in the pattern that have the base weight for the specified 233 * strength are treated as "wildcards" that match an element with any 234 * other weight at that collation level in the searched text. For 235 * example, with a secondary-strength English collator, a plain 'e' in 236 * the pattern will match a plain e or an e with any diacritic in the 237 * searched text, but an e with diacritic in the pattern will only 238 * match an e with the same diacritic in the searched text. 239 * 240 * This supports "asymmetric search" as described in 241 * <a href="http://www.unicode.org/reports/tr10/#Asymmetric_Search"> 242 * UTS #10 Unicode Collation Algorithm</a>. 243 * 244 * @stable ICU 4.4 245 */ 246 USEARCH_PATTERN_BASE_WEIGHT_IS_WILDCARD, 247 /** 248 * Value for USEARCH_ELEMENT_COMPARISON. 249 * collation element comparison is modified to effectively provide 250 * behavior between the specified strength and strength - 1. Collation 251 * elements in either the pattern or the searched text that have the 252 * base weight for the specified strength are treated as "wildcards" 253 * that match an element with any other weight at that collation level. 254 * For example, with a secondary-strength English collator, a plain 'e' 255 * in the pattern will match a plain e or an e with any diacritic in the 256 * searched text, but an e with diacritic in the pattern will only 257 * match an e with the same diacritic or a plain e in the searched text. 258 * 259 * This option is similar to "asymmetric search" as described in 260 * <a href="http://www.unicode.org/reports/tr10/#Asymmetric_Search"> 261 * UTS #10 Unicode Collation Algorithm</a, but also allows unmarked 262 * characters in the searched text to match marked or unmarked versions of 263 * that character in the pattern. 264 * 265 * @stable ICU 4.4 266 */ 267 USEARCH_ANY_BASE_WEIGHT_IS_WILDCARD, 268 269#ifndef U_HIDE_DEPRECATED_API 270 /** 271 * One more than the highest normal USearchAttributeValue value. 272 * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420. 273 */ 274 USEARCH_ATTRIBUTE_VALUE_COUNT 275#endif // U_HIDE_DEPRECATED_API 276} USearchAttributeValue; 277 278/* open and close ------------------------------------------------------ */ 279 280/** 281* Creating a search iterator data struct using the argument locale language 282* rule set. A collator will be created in the process, which will be owned by 283* this search and will be deleted in <tt>usearch_close</tt>. 284* @param pattern for matching 285* @param patternlength length of the pattern, -1 for null-termination 286* @param text text string 287* @param textlength length of the text string, -1 for null-termination 288* @param locale name of locale for the rules to be used 289* @param breakiter A BreakIterator that will be used to restrict the points 290* at which matches are detected. If a match is found, but 291* the match's start or end index is not a boundary as 292* determined by the <tt>BreakIterator</tt>, the match will 293* be rejected and another will be searched for. 294* If this parameter is <tt>NULL</tt>, no break detection is 295* attempted. 296* @param status for errors if it occurs. If pattern or text is NULL, or if 297* patternlength or textlength is 0 then an 298* U_ILLEGAL_ARGUMENT_ERROR is returned. 299* @return search iterator data structure, or NULL if there is an error. 300* @stable ICU 2.4 301*/ 302U_STABLE UStringSearch * U_EXPORT2 usearch_open(const UChar *pattern, 303 int32_t patternlength, 304 const UChar *text, 305 int32_t textlength, 306 const char *locale, 307 UBreakIterator *breakiter, 308 UErrorCode *status); 309 310/** 311* Creating a search iterator data struct using the argument collator language 312* rule set. Note, user retains the ownership of this collator, thus the 313* responsibility of deletion lies with the user. 314* NOTE: string search cannot be instantiated from a collator that has 315* collate digits as numbers (CODAN) turned on. 316* @param pattern for matching 317* @param patternlength length of the pattern, -1 for null-termination 318* @param text text string 319* @param textlength length of the text string, -1 for null-termination 320* @param collator used for the language rules 321* @param breakiter A BreakIterator that will be used to restrict the points 322* at which matches are detected. If a match is found, but 323* the match's start or end index is not a boundary as 324* determined by the <tt>BreakIterator</tt>, the match will 325* be rejected and another will be searched for. 326* If this parameter is <tt>NULL</tt>, no break detection is 327* attempted. 328* @param status for errors if it occurs. If collator, pattern or text is NULL, 329* or if patternlength or textlength is 0 then an 330* U_ILLEGAL_ARGUMENT_ERROR is returned. 331* @return search iterator data structure, or NULL if there is an error. 332* @stable ICU 2.4 333*/ 334U_STABLE UStringSearch * U_EXPORT2 usearch_openFromCollator( 335 const UChar *pattern, 336 int32_t patternlength, 337 const UChar *text, 338 int32_t textlength, 339 const UCollator *collator, 340 UBreakIterator *breakiter, 341 UErrorCode *status); 342 343/** 344* Destroying and cleaning up the search iterator data struct. 345* If a collator is created in <tt>usearch_open</tt>, it will be destroyed here. 346* @param searchiter data struct to clean up 347* @stable ICU 2.4 348*/ 349U_STABLE void U_EXPORT2 usearch_close(UStringSearch *searchiter); 350 351#if U_SHOW_CPLUSPLUS_API 352 353U_NAMESPACE_BEGIN 354 355/** 356 * \class LocalUStringSearchPointer 357 * "Smart pointer" class, closes a UStringSearch via usearch_close(). 358 * For most methods see the LocalPointerBase base class. 359 * 360 * @see LocalPointerBase 361 * @see LocalPointer 362 * @stable ICU 4.4 363 */ 364U_DEFINE_LOCAL_OPEN_POINTER(LocalUStringSearchPointer, UStringSearch, usearch_close); 365 366U_NAMESPACE_END 367 368#endif 369 370/* get and set methods -------------------------------------------------- */ 371 372/** 373* Sets the current position in the text string which the next search will 374* start from. Clears previous states. 375* This method takes the argument index and sets the position in the text 376* string accordingly without checking if the index is pointing to a 377* valid starting point to begin searching. 378* Search positions that may render incorrect results are highlighted in the 379* header comments 380* @param strsrch search iterator data struct 381* @param position position to start next search from. If position is less 382* than or greater than the text range for searching, 383* an U_INDEX_OUTOFBOUNDS_ERROR will be returned 384* @param status error status if any. 385* @stable ICU 2.4 386*/ 387U_STABLE void U_EXPORT2 usearch_setOffset(UStringSearch *strsrch, 388 int32_t position, 389 UErrorCode *status); 390 391/** 392* Return the current index in the string text being searched. 393* If the iteration has gone past the end of the text (or past the beginning 394* for a backwards search), <tt>USEARCH_DONE</tt> is returned. 395* @param strsrch search iterator data struct 396* @see #USEARCH_DONE 397* @stable ICU 2.4 398*/ 399U_STABLE int32_t U_EXPORT2 usearch_getOffset(const UStringSearch *strsrch); 400 401/** 402* Sets the text searching attributes located in the enum USearchAttribute 403* with values from the enum USearchAttributeValue. 404* <tt>USEARCH_DEFAULT</tt> can be used for all attributes for resetting. 405* @param strsrch search iterator data struct 406* @param attribute text attribute to be set 407* @param value text attribute value 408* @param status for errors if it occurs 409* @see #usearch_getAttribute 410* @stable ICU 2.4 411*/ 412U_STABLE void U_EXPORT2 usearch_setAttribute(UStringSearch *strsrch, 413 USearchAttribute attribute, 414 USearchAttributeValue value, 415 UErrorCode *status); 416 417/** 418* Gets the text searching attributes. 419* @param strsrch search iterator data struct 420* @param attribute text attribute to be retrieve 421* @return text attribute value 422* @see #usearch_setAttribute 423* @stable ICU 2.4 424*/ 425U_STABLE USearchAttributeValue U_EXPORT2 usearch_getAttribute( 426 const UStringSearch *strsrch, 427 USearchAttribute attribute); 428 429/** 430* Returns the index to the match in the text string that was searched. 431* This call returns a valid result only after a successful call to 432* <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 433* or <tt>usearch_last</tt>. 434* Just after construction, or after a searching method returns 435* <tt>USEARCH_DONE</tt>, this method will return <tt>USEARCH_DONE</tt>. 436* <p> 437* Use <tt>usearch_getMatchedLength</tt> to get the matched string length. 438* @param strsrch search iterator data struct 439* @return index to a substring within the text string that is being 440* searched. 441* @see #usearch_first 442* @see #usearch_next 443* @see #usearch_previous 444* @see #usearch_last 445* @see #USEARCH_DONE 446* @stable ICU 2.4 447*/ 448U_STABLE int32_t U_EXPORT2 usearch_getMatchedStart( 449 const UStringSearch *strsrch); 450 451/** 452* Returns the length of text in the string which matches the search pattern. 453* This call returns a valid result only after a successful call to 454* <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 455* or <tt>usearch_last</tt>. 456* Just after construction, or after a searching method returns 457* <tt>USEARCH_DONE</tt>, this method will return 0. 458* @param strsrch search iterator data struct 459* @return The length of the match in the string text, or 0 if there is no 460* match currently. 461* @see #usearch_first 462* @see #usearch_next 463* @see #usearch_previous 464* @see #usearch_last 465* @see #USEARCH_DONE 466* @stable ICU 2.4 467*/ 468U_STABLE int32_t U_EXPORT2 usearch_getMatchedLength( 469 const UStringSearch *strsrch); 470 471/** 472* Returns the text that was matched by the most recent call to 473* <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 474* or <tt>usearch_last</tt>. 475* If the iterator is not pointing at a valid match (e.g. just after 476* construction or after <tt>USEARCH_DONE</tt> has been returned, returns 477* an empty string. If result is not large enough to store the matched text, 478* result will be filled with the partial text and an U_BUFFER_OVERFLOW_ERROR 479* will be returned in status. result will be null-terminated whenever 480* possible. If the buffer fits the matched text exactly, a null-termination 481* is not possible, then a U_STRING_NOT_TERMINATED_ERROR set in status. 482* Pre-flighting can be either done with length = 0 or the API 483* <tt>usearch_getMatchLength</tt>. 484* @param strsrch search iterator data struct 485* @param result UChar buffer to store the matched string 486* @param resultCapacity length of the result buffer 487* @param status error returned if result is not large enough 488* @return exact length of the matched text, not counting the null-termination 489* @see #usearch_first 490* @see #usearch_next 491* @see #usearch_previous 492* @see #usearch_last 493* @see #USEARCH_DONE 494* @stable ICU 2.4 495*/ 496U_STABLE int32_t U_EXPORT2 usearch_getMatchedText(const UStringSearch *strsrch, 497 UChar *result, 498 int32_t resultCapacity, 499 UErrorCode *status); 500 501#if !UCONFIG_NO_BREAK_ITERATION 502 503/** 504* Set the BreakIterator that will be used to restrict the points at which 505* matches are detected. 506* @param strsrch search iterator data struct 507* @param breakiter A BreakIterator that will be used to restrict the points 508* at which matches are detected. If a match is found, but 509* the match's start or end index is not a boundary as 510* determined by the <tt>BreakIterator</tt>, the match will 511* be rejected and another will be searched for. 512* If this parameter is <tt>NULL</tt>, no break detection is 513* attempted. 514* @param status for errors if it occurs 515* @see #usearch_getBreakIterator 516* @stable ICU 2.4 517*/ 518U_STABLE void U_EXPORT2 usearch_setBreakIterator(UStringSearch *strsrch, 519 UBreakIterator *breakiter, 520 UErrorCode *status); 521 522/** 523* Returns the BreakIterator that is used to restrict the points at which 524* matches are detected. This will be the same object that was passed to the 525* constructor or to <tt>usearch_setBreakIterator</tt>. Note that 526* <tt>NULL</tt> 527* is a legal value; it means that break detection should not be attempted. 528* @param strsrch search iterator data struct 529* @return break iterator used 530* @see #usearch_setBreakIterator 531* @stable ICU 2.4 532*/ 533U_STABLE const UBreakIterator * U_EXPORT2 usearch_getBreakIterator( 534 const UStringSearch *strsrch); 535 536#endif 537 538/** 539* Set the string text to be searched. Text iteration will hence begin at the 540* start of the text string. This method is useful if you want to re-use an 541* iterator to search for the same pattern within a different body of text. 542* @param strsrch search iterator data struct 543* @param text new string to look for match 544* @param textlength length of the new string, -1 for null-termination 545* @param status for errors if it occurs. If text is NULL, or textlength is 0 546* then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change 547* done to strsrch. 548* @see #usearch_getText 549* @stable ICU 2.4 550*/ 551U_STABLE void U_EXPORT2 usearch_setText( UStringSearch *strsrch, 552 const UChar *text, 553 int32_t textlength, 554 UErrorCode *status); 555 556/** 557* Return the string text to be searched. 558* @param strsrch search iterator data struct 559* @param length returned string text length 560* @return string text 561* @see #usearch_setText 562* @stable ICU 2.4 563*/ 564U_STABLE const UChar * U_EXPORT2 usearch_getText(const UStringSearch *strsrch, 565 int32_t *length); 566 567/** 568* Gets the collator used for the language rules. 569* <p> 570* Deleting the returned <tt>UCollator</tt> before calling 571* <tt>usearch_close</tt> would cause the string search to fail. 572* <tt>usearch_close</tt> will delete the collator if this search owns it. 573* @param strsrch search iterator data struct 574* @return collator 575* @stable ICU 2.4 576*/ 577U_STABLE UCollator * U_EXPORT2 usearch_getCollator( 578 const UStringSearch *strsrch); 579 580/** 581* Sets the collator used for the language rules. User retains the ownership 582* of this collator, thus the responsibility of deletion lies with the user. 583* This method causes internal data such as Boyer-Moore shift tables to 584* be recalculated, but the iterator's position is unchanged. 585* @param strsrch search iterator data struct 586* @param collator to be used 587* @param status for errors if it occurs 588* @stable ICU 2.4 589*/ 590U_STABLE void U_EXPORT2 usearch_setCollator( UStringSearch *strsrch, 591 const UCollator *collator, 592 UErrorCode *status); 593 594/** 595* Sets the pattern used for matching. 596* Internal data like the Boyer Moore table will be recalculated, but the 597* iterator's position is unchanged. 598* @param strsrch search iterator data struct 599* @param pattern string 600* @param patternlength pattern length, -1 for null-terminated string 601* @param status for errors if it occurs. If text is NULL, or textlength is 0 602* then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change 603* done to strsrch. 604* @stable ICU 2.4 605*/ 606U_STABLE void U_EXPORT2 usearch_setPattern( UStringSearch *strsrch, 607 const UChar *pattern, 608 int32_t patternlength, 609 UErrorCode *status); 610 611/** 612* Gets the search pattern 613* @param strsrch search iterator data struct 614* @param length return length of the pattern, -1 indicates that the pattern 615* is null-terminated 616* @return pattern string 617* @stable ICU 2.4 618*/ 619U_STABLE const UChar * U_EXPORT2 usearch_getPattern( 620 const UStringSearch *strsrch, 621 int32_t *length); 622 623/* methods ------------------------------------------------------------- */ 624 625/** 626* Returns the first index at which the string text matches the search 627* pattern. 628* The iterator is adjusted so that its current index (as returned by 629* <tt>usearch_getOffset</tt>) is the match position if one was found. 630* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 631* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>. 632* @param strsrch search iterator data struct 633* @param status for errors if it occurs 634* @return The character index of the first match, or 635* <tt>USEARCH_DONE</tt> if there are no matches. 636* @see #usearch_getOffset 637* @see #USEARCH_DONE 638* @stable ICU 2.4 639*/ 640U_STABLE int32_t U_EXPORT2 usearch_first(UStringSearch *strsrch, 641 UErrorCode *status); 642 643/** 644* Returns the first index equal or greater than <tt>position</tt> at which 645* the string text 646* matches the search pattern. The iterator is adjusted so that its current 647* index (as returned by <tt>usearch_getOffset</tt>) is the match position if 648* one was found. 649* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 650* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 651* <p> 652* Search positions that may render incorrect results are highlighted in the 653* header comments. If position is less than or greater than the text range 654* for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned 655* @param strsrch search iterator data struct 656* @param position to start the search at 657* @param status for errors if it occurs 658* @return The character index of the first match following <tt>pos</tt>, 659* or <tt>USEARCH_DONE</tt> if there are no matches. 660* @see #usearch_getOffset 661* @see #USEARCH_DONE 662* @stable ICU 2.4 663*/ 664U_STABLE int32_t U_EXPORT2 usearch_following(UStringSearch *strsrch, 665 int32_t position, 666 UErrorCode *status); 667 668/** 669* Returns the last index in the target text at which it matches the search 670* pattern. The iterator is adjusted so that its current 671* index (as returned by <tt>usearch_getOffset</tt>) is the match position if 672* one was found. 673* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 674* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>. 675* @param strsrch search iterator data struct 676* @param status for errors if it occurs 677* @return The index of the first match, or <tt>USEARCH_DONE</tt> if there 678* are no matches. 679* @see #usearch_getOffset 680* @see #USEARCH_DONE 681* @stable ICU 2.4 682*/ 683U_STABLE int32_t U_EXPORT2 usearch_last(UStringSearch *strsrch, 684 UErrorCode *status); 685 686/** 687* Returns the first index less than <tt>position</tt> at which the string text 688* matches the search pattern. The iterator is adjusted so that its current 689* index (as returned by <tt>usearch_getOffset</tt>) is the match position if 690* one was found. 691* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 692* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 693* <p> 694* Search positions that may render incorrect results are highlighted in the 695* header comments. If position is less than or greater than the text range 696* for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned. 697* <p> 698* When <tt>USEARCH_OVERLAP</tt> option is off, the last index of the 699* result match is always less than <tt>position</tt>. 700* When <tt>USERARCH_OVERLAP</tt> is on, the result match may span across 701* <tt>position</tt>. 702* @param strsrch search iterator data struct 703* @param position index position the search is to begin at 704* @param status for errors if it occurs 705* @return The character index of the first match preceding <tt>pos</tt>, 706* or <tt>USEARCH_DONE</tt> if there are no matches. 707* @see #usearch_getOffset 708* @see #USEARCH_DONE 709* @stable ICU 2.4 710*/ 711U_STABLE int32_t U_EXPORT2 usearch_preceding(UStringSearch *strsrch, 712 int32_t position, 713 UErrorCode *status); 714 715/** 716* Returns the index of the next point at which the string text matches the 717* search pattern, starting from the current position. 718* The iterator is adjusted so that its current 719* index (as returned by <tt>usearch_getOffset</tt>) is the match position if 720* one was found. 721* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 722* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 723* @param strsrch search iterator data struct 724* @param status for errors if it occurs 725* @return The index of the next match after the current position, or 726* <tt>USEARCH_DONE</tt> if there are no more matches. 727* @see #usearch_first 728* @see #usearch_getOffset 729* @see #USEARCH_DONE 730* @stable ICU 2.4 731*/ 732U_STABLE int32_t U_EXPORT2 usearch_next(UStringSearch *strsrch, 733 UErrorCode *status); 734 735/** 736* Returns the index of the previous point at which the string text matches 737* the search pattern, starting at the current position. 738* The iterator is adjusted so that its current 739* index (as returned by <tt>usearch_getOffset</tt>) is the match position if 740* one was found. 741* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and 742* the iterator will be adjusted to the index <tt>USEARCH_DONE</tt> 743* @param strsrch search iterator data struct 744* @param status for errors if it occurs 745* @return The index of the previous match before the current position, 746* or <tt>USEARCH_DONE</tt> if there are no more matches. 747* @see #usearch_last 748* @see #usearch_getOffset 749* @see #USEARCH_DONE 750* @stable ICU 2.4 751*/ 752U_STABLE int32_t U_EXPORT2 usearch_previous(UStringSearch *strsrch, 753 UErrorCode *status); 754 755/** 756* Reset the iteration. 757* Search will begin at the start of the text string if a forward iteration 758* is initiated before a backwards iteration. Otherwise if a backwards 759* iteration is initiated before a forwards iteration, the search will begin 760* at the end of the text string. 761* @param strsrch search iterator data struct 762* @see #usearch_first 763* @stable ICU 2.4 764*/ 765U_STABLE void U_EXPORT2 usearch_reset(UStringSearch *strsrch); 766 767#ifndef U_HIDE_INTERNAL_API 768/** 769 * Simple forward search for the pattern, starting at a specified index, 770 * and using using a default set search options. 771 * 772 * This is an experimental function, and is not an official part of the 773 * ICU API. 774 * 775 * The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored. 776 * 777 * The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and 778 * any Break Iterator are ignored. 779 * 780 * Matches obey the following constraints: 781 * 782 * Characters at the start or end positions of a match that are ignorable 783 * for collation are not included as part of the match, unless they 784 * are part of a combining sequence, as described below. 785 * 786 * A match will not include a partial combining sequence. Combining 787 * character sequences are considered to be inseperable units, 788 * and either match the pattern completely, or are considered to not match 789 * at all. Thus, for example, an A followed a combining accent mark will 790 * not be found when searching for a plain (unaccented) A. (unless 791 * the collation strength has been set to ignore all accents). 792 * 793 * When beginning a search, the initial starting position, startIdx, 794 * is assumed to be an acceptable match boundary with respect to 795 * combining characters. A combining sequence that spans across the 796 * starting point will not supress a match beginning at startIdx. 797 * 798 * Characters that expand to multiple collation elements 799 * (German sharp-S becoming 'ss', or the composed forms of accented 800 * characters, for example) also must match completely. 801 * Searching for a single 's' in a string containing only a sharp-s will 802 * find no match. 803 * 804 * 805 * @param strsrch the UStringSearch struct, which references both 806 * the text to be searched and the pattern being sought. 807 * @param startIdx The index into the text to begin the search. 808 * @param matchStart An out parameter, the starting index of the matched text. 809 * This parameter may be NULL. 810 * A value of -1 will be returned if no match was found. 811 * @param matchLimit Out parameter, the index of the first position following the matched text. 812 * The matchLimit will be at a suitable position for beginning a subsequent search 813 * in the input text. 814 * This parameter may be NULL. 815 * A value of -1 will be returned if no match was found. 816 * 817 * @param status Report any errors. Note that no match found is not an error. 818 * @return TRUE if a match was found, FALSE otherwise. 819 * 820 * @internal 821 */ 822U_INTERNAL UBool U_EXPORT2 usearch_search(UStringSearch *strsrch, 823 int32_t startIdx, 824 int32_t *matchStart, 825 int32_t *matchLimit, 826 UErrorCode *status); 827 828/** 829 * Simple backwards search for the pattern, starting at a specified index, 830 * and using using a default set search options. 831 * 832 * This is an experimental function, and is not an official part of the 833 * ICU API. 834 * 835 * The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored. 836 * 837 * The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and 838 * any Break Iterator are ignored. 839 * 840 * Matches obey the following constraints: 841 * 842 * Characters at the start or end positions of a match that are ignorable 843 * for collation are not included as part of the match, unless they 844 * are part of a combining sequence, as described below. 845 * 846 * A match will not include a partial combining sequence. Combining 847 * character sequences are considered to be inseperable units, 848 * and either match the pattern completely, or are considered to not match 849 * at all. Thus, for example, an A followed a combining accent mark will 850 * not be found when searching for a plain (unaccented) A. (unless 851 * the collation strength has been set to ignore all accents). 852 * 853 * When beginning a search, the initial starting position, startIdx, 854 * is assumed to be an acceptable match boundary with respect to 855 * combining characters. A combining sequence that spans across the 856 * starting point will not supress a match beginning at startIdx. 857 * 858 * Characters that expand to multiple collation elements 859 * (German sharp-S becoming 'ss', or the composed forms of accented 860 * characters, for example) also must match completely. 861 * Searching for a single 's' in a string containing only a sharp-s will 862 * find no match. 863 * 864 * 865 * @param strsrch the UStringSearch struct, which references both 866 * the text to be searched and the pattern being sought. 867 * @param startIdx The index into the text to begin the search. 868 * @param matchStart An out parameter, the starting index of the matched text. 869 * This parameter may be NULL. 870 * A value of -1 will be returned if no match was found. 871 * @param matchLimit Out parameter, the index of the first position following the matched text. 872 * The matchLimit will be at a suitable position for beginning a subsequent search 873 * in the input text. 874 * This parameter may be NULL. 875 * A value of -1 will be returned if no match was found. 876 * 877 * @param status Report any errors. Note that no match found is not an error. 878 * @return TRUE if a match was found, FALSE otherwise. 879 * 880 * @internal 881 */ 882U_INTERNAL UBool U_EXPORT2 usearch_searchBackwards(UStringSearch *strsrch, 883 int32_t startIdx, 884 int32_t *matchStart, 885 int32_t *matchLimit, 886 UErrorCode *status); 887#endif /* U_HIDE_INTERNAL_API */ 888 889#endif /* #if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION */ 890 891#endif 892