icuSources/i18n/unicode/usearch.h

   1 // © 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 &szlig; 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 occurrences 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_getMatchedLength(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 */
 153 struct UStringSearch;
 154 /**
 155 * Data structure for searching
 156 * @stable ICU 2.4
 157 */
 158 typedef struct UStringSearch UStringSearch;
 159
 160 /**
 161 * @stable ICU 2.4
 162 */
 163 typedef 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 */
 205 typedef 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      * [UTS #10 Unicode Collation Algorithm](http://www.unicode.org/reports/tr10/#Asymmetric_Search),
 261      * but also allows unmarked characters in the searched text to match
 262      * marked or unmarked versions of that character in the pattern.
 263      *
 264      * @stable ICU 4.4
 265      */
 266     USEARCH_ANY_BASE_WEIGHT_IS_WILDCARD,
 267
 268 #ifndef U_HIDE_DEPRECATED_API
 269     /**
 270      * One more than the highest normal USearchAttributeValue value.
 271      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
 272      */
 273     USEARCH_ATTRIBUTE_VALUE_COUNT
 274 #endif  /* U_HIDE_DEPRECATED_API */
 275 } USearchAttributeValue;
 276
 277 /* open and close ------------------------------------------------------ */
 278
 279 /**
 280 * Creating a search iterator data struct using the argument locale language
 281 * rule set. A collator will be created in the process, which will be owned by
 282 * this search and will be deleted in <tt>usearch_close</tt>.
 283 * @param pattern for matching
 284 * @param patternlength length of the pattern, -1 for null-termination
 285 * @param text text string
 286 * @param textlength length of the text string, -1 for null-termination
 287 * @param locale name of locale for the rules to be used
 288 * @param breakiter A BreakIterator that will be used to restrict the points
 289 *                  at which matches are detected. If a match is found, but
 290 *                  the match's start or end index is not a boundary as
 291 *                  determined by the <tt>BreakIterator</tt>, the match will
 292 *                  be rejected and another will be searched for.
 293 *                  If this parameter is <tt>NULL</tt>, no break detection is
 294 *                  attempted.
 295 * @param status for errors if it occurs. If pattern or text is NULL, or if
 296 *               patternlength or textlength is 0 then an
 297 *               U_ILLEGAL_ARGUMENT_ERROR is returned.
 298 * @return search iterator data structure, or NULL if there is an error.
 299 * @stable ICU 2.4
 300 */
 301 U_STABLE UStringSearch * U_EXPORT2 usearch_open(const UChar          *pattern,
 302                                               int32_t         patternlength,
 303                                         const UChar          *text,
 304                                               int32_t         textlength,
 305                                         const char           *locale,
 306                                               UBreakIterator *breakiter,
 307                                               UErrorCode     *status);
 308
 309 /**
 310 * Creating a search iterator data struct using the argument collator language
 311 * rule set. Note, user retains the ownership of this collator, thus the
 312 * responsibility of deletion lies with the user.
 313 * NOTE: string search cannot be instantiated from a collator that has
 314 * collate digits as numbers (CODAN) turned on.
 315 * @param pattern for matching
 316 * @param patternlength length of the pattern, -1 for null-termination
 317 * @param text text string
 318 * @param textlength length of the text string, -1 for null-termination
 319 * @param collator used for the language rules
 320 * @param breakiter A BreakIterator that will be used to restrict the points
 321 *                  at which matches are detected. If a match is found, but
 322 *                  the match's start or end index is not a boundary as
 323 *                  determined by the <tt>BreakIterator</tt>, the match will
 324 *                  be rejected and another will be searched for.
 325 *                  If this parameter is <tt>NULL</tt>, no break detection is
 326 *                  attempted.
 327 * @param status for errors if it occurs. If collator, pattern or text is NULL,
 328 *               or if patternlength or textlength is 0 then an
 329 *               U_ILLEGAL_ARGUMENT_ERROR is returned.
 330 * @return search iterator data structure, or NULL if there is an error.
 331 * @stable ICU 2.4
 332 */
 333 U_STABLE UStringSearch * U_EXPORT2 usearch_openFromCollator(
 334                                          const UChar *pattern,
 335                                                int32_t         patternlength,
 336                                          const UChar          *text,
 337                                                int32_t         textlength,
 338                                          const UCollator      *collator,
 339                                                UBreakIterator *breakiter,
 340                                                UErrorCode     *status);
 341
 342 /**
 343 * Destroying and cleaning up the search iterator data struct.
 344 * If a collator is created in <tt>usearch_open</tt>, it will be destroyed here.
 345 * @param searchiter data struct to clean up
 346 * @stable ICU 2.4
 347 */
 348 U_STABLE void U_EXPORT2 usearch_close(UStringSearch *searchiter);
 349
 350 #if U_SHOW_CPLUSPLUS_API
 351
 352 U_NAMESPACE_BEGIN
 353
 354 /**
 355  * \class LocalUStringSearchPointer
 356  * "Smart pointer" class, closes a UStringSearch via usearch_close().
 357  * For most methods see the LocalPointerBase base class.
 358  *
 359  * @see LocalPointerBase
 360  * @see LocalPointer
 361  * @stable ICU 4.4
 362  */
 363 U_DEFINE_LOCAL_OPEN_POINTER(LocalUStringSearchPointer, UStringSearch, usearch_close);
 364
 365 U_NAMESPACE_END
 366
 367 #endif
 368
 369 /* get and set methods -------------------------------------------------- */
 370
 371 /**
 372 * Sets the current position in the text string which the next search will
 373 * start from. Clears previous states.
 374 * This method takes the argument index and sets the position in the text
 375 * string accordingly without checking if the index is pointing to a
 376 * valid starting point to begin searching.
 377 * Search positions that may render incorrect results are highlighted in the
 378 * header comments
 379 * @param strsrch search iterator data struct
 380 * @param position position to start next search from. If position is less
 381 *          than or greater than the text range for searching,
 382 *          an U_INDEX_OUTOFBOUNDS_ERROR will be returned
 383 * @param status error status if any.
 384 * @stable ICU 2.4
 385 */
 386 U_STABLE void U_EXPORT2 usearch_setOffset(UStringSearch *strsrch,
 387                                         int32_t    position,
 388                                         UErrorCode    *status);
 389
 390 /**
 391 * Return the current index in the string text being searched.
 392 * If the iteration has gone past the end of the text (or past the beginning
 393 * for a backwards search), <tt>USEARCH_DONE</tt> is returned.
 394 * @param strsrch search iterator data struct
 395 * @see #USEARCH_DONE
 396 * @stable ICU 2.4
 397 */
 398 U_STABLE int32_t U_EXPORT2 usearch_getOffset(const UStringSearch *strsrch);
 399
 400 /**
 401 * Sets the text searching attributes located in the enum USearchAttribute
 402 * with values from the enum USearchAttributeValue.
 403 * <tt>USEARCH_DEFAULT</tt> can be used for all attributes for resetting.
 404 * @param strsrch search iterator data struct
 405 * @param attribute text attribute to be set
 406 * @param value text attribute value
 407 * @param status for errors if it occurs
 408 * @see #usearch_getAttribute
 409 * @stable ICU 2.4
 410 */
 411 U_STABLE void U_EXPORT2 usearch_setAttribute(UStringSearch         *strsrch,
 412                                            USearchAttribute       attribute,
 413                                            USearchAttributeValue  value,
 414                                            UErrorCode            *status);
 415
 416 /**
 417 * Gets the text searching attributes.
 418 * @param strsrch search iterator data struct
 419 * @param attribute text attribute to be retrieve
 420 * @return text attribute value
 421 * @see #usearch_setAttribute
 422 * @stable ICU 2.4
 423 */
 424 U_STABLE USearchAttributeValue U_EXPORT2 usearch_getAttribute(
 425                                          const UStringSearch    *strsrch,
 426                                                USearchAttribute  attribute);
 427
 428 /**
 429 * Returns the index to the match in the text string that was searched.
 430 * This call returns a valid result only after a successful call to
 431 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>,
 432 * or <tt>usearch_last</tt>.
 433 * Just after construction, or after a searching method returns
 434 * <tt>USEARCH_DONE</tt>, this method will return <tt>USEARCH_DONE</tt>.
 435 * <p>
 436 * Use <tt>usearch_getMatchedLength</tt> to get the matched string length.
 437 * @param strsrch search iterator data struct
 438 * @return index to a substring within the text string that is being
 439 *         searched.
 440 * @see #usearch_first
 441 * @see #usearch_next
 442 * @see #usearch_previous
 443 * @see #usearch_last
 444 * @see #USEARCH_DONE
 445 * @stable ICU 2.4
 446 */
 447 U_STABLE int32_t U_EXPORT2 usearch_getMatchedStart(
 448                                                const UStringSearch *strsrch);
 449
 450 /**
 451 * Returns the length of text in the string which matches the search pattern.
 452 * This call returns a valid result only after a successful call to
 453 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>,
 454 * or <tt>usearch_last</tt>.
 455 * Just after construction, or after a searching method returns
 456 * <tt>USEARCH_DONE</tt>, this method will return 0.
 457 * @param strsrch search iterator data struct
 458 * @return The length of the match in the string text, or 0 if there is no
 459 *         match currently.
 460 * @see #usearch_first
 461 * @see #usearch_next
 462 * @see #usearch_previous
 463 * @see #usearch_last
 464 * @see #USEARCH_DONE
 465 * @stable ICU 2.4
 466 */
 467 U_STABLE int32_t U_EXPORT2 usearch_getMatchedLength(
 468                                                const UStringSearch *strsrch);
 469
 470 /**
 471 * Returns the text that was matched by the most recent call to
 472 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>,
 473 * or <tt>usearch_last</tt>.
 474 * If the iterator is not pointing at a valid match (e.g. just after
 475 * construction or after <tt>USEARCH_DONE</tt> has been returned, returns
 476 * an empty string. If result is not large enough to store the matched text,
 477 * result will be filled with the partial text and an U_BUFFER_OVERFLOW_ERROR
 478 * will be returned in status. result will be null-terminated whenever
 479 * possible. If the buffer fits the matched text exactly, a null-termination
 480 * is not possible, then a U_STRING_NOT_TERMINATED_ERROR set in status.
 481 * Pre-flighting can be either done with length = 0 or the API
 482 * <tt>usearch_getMatchedLength</tt>.
 483 * @param strsrch search iterator data struct
 484 * @param result UChar buffer to store the matched string
 485 * @param resultCapacity length of the result buffer
 486 * @param status error returned if result is not large enough
 487 * @return exact length of the matched text, not counting the null-termination
 488 * @see #usearch_first
 489 * @see #usearch_next
 490 * @see #usearch_previous
 491 * @see #usearch_last
 492 * @see #USEARCH_DONE
 493 * @stable ICU 2.4
 494 */
 495 U_STABLE int32_t U_EXPORT2 usearch_getMatchedText(const UStringSearch *strsrch,
 496                                             UChar         *result,
 497                                             int32_t        resultCapacity,
 498                                             UErrorCode    *status);
 499
 500 #if !UCONFIG_NO_BREAK_ITERATION
 501
 502 /**
 503 * Set the BreakIterator that will be used to restrict the points at which
 504 * matches are detected.
 505 * @param strsrch search iterator data struct
 506 * @param breakiter A BreakIterator that will be used to restrict the points
 507 *                  at which matches are detected. If a match is found, but
 508 *                  the match's start or end index is not a boundary as
 509 *                  determined by the <tt>BreakIterator</tt>, the match will
 510 *                  be rejected and another will be searched for.
 511 *                  If this parameter is <tt>NULL</tt>, no break detection is
 512 *                  attempted.
 513 * @param status for errors if it occurs
 514 * @see #usearch_getBreakIterator
 515 * @stable ICU 2.4
 516 */
 517 U_STABLE void U_EXPORT2 usearch_setBreakIterator(UStringSearch  *strsrch,
 518                                                UBreakIterator *breakiter,
 519                                                UErrorCode     *status);
 520
 521 /**
 522 * Returns the BreakIterator that is used to restrict the points at which
 523 * matches are detected. This will be the same object that was passed to the
 524 * constructor or to <tt>usearch_setBreakIterator</tt>. Note that
 525 * <tt>NULL</tt>
 526 * is a legal value; it means that break detection should not be attempted.
 527 * @param strsrch search iterator data struct
 528 * @return break iterator used
 529 * @see #usearch_setBreakIterator
 530 * @stable ICU 2.4
 531 */
 532 U_STABLE const UBreakIterator * U_EXPORT2 usearch_getBreakIterator(
 533                                               const UStringSearch *strsrch);
 534
 535 #endif
 536
 537 /**
 538 * Set the string text to be searched. Text iteration will hence begin at the
 539 * start of the text string. This method is useful if you want to re-use an
 540 * iterator to search for the same pattern within a different body of text.
 541 * @param strsrch search iterator data struct
 542 * @param text new string to look for match
 543 * @param textlength length of the new string, -1 for null-termination
 544 * @param status for errors if it occurs. If text is NULL, or textlength is 0
 545 *               then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change
 546 *               done to strsrch.
 547 * @see #usearch_getText
 548 * @stable ICU 2.4
 549 */
 550 U_STABLE void U_EXPORT2 usearch_setText(      UStringSearch *strsrch,
 551                                       const UChar         *text,
 552                                             int32_t        textlength,
 553                                             UErrorCode    *status);
 554
 555 /**
 556 * Return the string text to be searched.
 557 * @param strsrch search iterator data struct
 558 * @param length returned string text length
 559 * @return string text
 560 * @see #usearch_setText
 561 * @stable ICU 2.4
 562 */
 563 U_STABLE const UChar * U_EXPORT2 usearch_getText(const UStringSearch *strsrch,
 564                                                int32_t       *length);
 565
 566 /**
 567 * Gets the collator used for the language rules.
 568 * <p>
 569 * Deleting the returned <tt>UCollator</tt> before calling
 570 * <tt>usearch_close</tt> would cause the string search to fail.
 571 * <tt>usearch_close</tt> will delete the collator if this search owns it.
 572 * @param strsrch search iterator data struct
 573 * @return collator
 574 * @stable ICU 2.4
 575 */
 576 U_STABLE UCollator * U_EXPORT2 usearch_getCollator(
 577                                                const UStringSearch *strsrch);
 578
 579 /**
 580 * Sets the collator used for the language rules. User retains the ownership
 581 * of this collator, thus the responsibility of deletion lies with the user.
 582 * This method causes internal data such as Boyer-Moore shift tables to
 583 * be recalculated, but the iterator's position is unchanged.
 584 * @param strsrch search iterator data struct
 585 * @param collator to be used
 586 * @param status for errors if it occurs
 587 * @stable ICU 2.4
 588 */
 589 U_STABLE void U_EXPORT2 usearch_setCollator(      UStringSearch *strsrch,
 590                                           const UCollator     *collator,
 591                                                 UErrorCode    *status);
 592
 593 /**
 594 * Sets the pattern used for matching.
 595 * Internal data like the Boyer Moore table will be recalculated, but the
 596 * iterator's position is unchanged.
 597 * @param strsrch search iterator data struct
 598 * @param pattern string
 599 * @param patternlength pattern length, -1 for null-terminated string
 600 * @param status for errors if it occurs. If text is NULL, or textlength is 0
 601 *               then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change
 602 *               done to strsrch.
 603 * @stable ICU 2.4
 604 */
 605 U_STABLE void U_EXPORT2 usearch_setPattern(      UStringSearch *strsrch,
 606                                          const UChar         *pattern,
 607                                                int32_t        patternlength,
 608                                                UErrorCode    *status);
 609
 610 /**
 611 * Gets the search pattern
 612 * @param strsrch search iterator data struct
 613 * @param length return length of the pattern, -1 indicates that the pattern
 614 *               is null-terminated
 615 * @return pattern string
 616 * @stable ICU 2.4
 617 */
 618 U_STABLE const UChar * U_EXPORT2 usearch_getPattern(
 619                                                const UStringSearch *strsrch,
 620                                                      int32_t       *length);
 621
 622 /* methods ------------------------------------------------------------- */
 623
 624 /**
 625 * Returns the first index at which the string text matches the search
 626 * pattern.
 627 * The iterator is adjusted so that its current index (as returned by
 628 * <tt>usearch_getOffset</tt>) is the match position if one was found.
 629 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 630 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>.
 631 * @param strsrch search iterator data struct
 632 * @param status for errors if it occurs
 633 * @return The character index of the first match, or
 634 * <tt>USEARCH_DONE</tt> if there are no matches.
 635 * @see #usearch_getOffset
 636 * @see #USEARCH_DONE
 637 * @stable ICU 2.4
 638 */
 639 U_STABLE int32_t U_EXPORT2 usearch_first(UStringSearch *strsrch,
 640                                            UErrorCode    *status);
 641
 642 /**
 643 * Returns the first index equal or greater than <tt>position</tt> at which
 644 * the string text
 645 * matches the search pattern. The iterator is adjusted so that its current
 646 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if
 647 * one was found.
 648 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 649 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>
 650 * <p>
 651 * Search positions that may render incorrect results are highlighted in the
 652 * header comments. If position is less than or greater than the text range
 653 * for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned
 654 * @param strsrch search iterator data struct
 655 * @param position to start the search at
 656 * @param status for errors if it occurs
 657 * @return The character index of the first match following <tt>pos</tt>,
 658 *         or <tt>USEARCH_DONE</tt> if there are no matches.
 659 * @see #usearch_getOffset
 660 * @see #USEARCH_DONE
 661 * @stable ICU 2.4
 662 */
 663 U_STABLE int32_t U_EXPORT2 usearch_following(UStringSearch *strsrch,
 664                                                int32_t    position,
 665                                                UErrorCode    *status);
 666
 667 /**
 668 * Returns the last index in the target text at which it matches the search
 669 * pattern. The iterator is adjusted so that its current
 670 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if
 671 * one was found.
 672 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 673 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>.
 674 * @param strsrch search iterator data struct
 675 * @param status for errors if it occurs
 676 * @return The index of the first match, or <tt>USEARCH_DONE</tt> if there
 677 *         are no matches.
 678 * @see #usearch_getOffset
 679 * @see #USEARCH_DONE
 680 * @stable ICU 2.4
 681 */
 682 U_STABLE int32_t U_EXPORT2 usearch_last(UStringSearch *strsrch,
 683                                           UErrorCode    *status);
 684
 685 /**
 686 * Returns the first index less than <tt>position</tt> at which the string text
 687 * matches the search pattern. The iterator is adjusted so that its current
 688 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if
 689 * one was found.
 690 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 691 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>
 692 * <p>
 693 * Search positions that may render incorrect results are highlighted in the
 694 * header comments. If position is less than or greater than the text range
 695 * for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned.
 696 * <p>
 697 * When <tt>USEARCH_OVERLAP</tt> option is off, the last index of the
 698 * result match is always less than <tt>position</tt>.
 699 * When <tt>USERARCH_OVERLAP</tt> is on, the result match may span across
 700 * <tt>position</tt>.
 701 * @param strsrch search iterator data struct
 702 * @param position index position the search is to begin at
 703 * @param status for errors if it occurs
 704 * @return The character index of the first match preceding <tt>pos</tt>,
 705 *         or <tt>USEARCH_DONE</tt> if there are no matches.
 706 * @see #usearch_getOffset
 707 * @see #USEARCH_DONE
 708 * @stable ICU 2.4
 709 */
 710 U_STABLE int32_t U_EXPORT2 usearch_preceding(UStringSearch *strsrch,
 711                                                int32_t    position,
 712                                                UErrorCode    *status);
 713
 714 /**
 715 * Returns the index of the next point at which the string text matches the
 716 * search pattern, starting from the current position.
 717 * The iterator is adjusted so that its current
 718 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if
 719 * one was found.
 720 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 721 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>
 722 * @param strsrch search iterator data struct
 723 * @param status for errors if it occurs
 724 * @return The index of the next match after the current position, or
 725 *         <tt>USEARCH_DONE</tt> if there are no more matches.
 726 * @see #usearch_first
 727 * @see #usearch_getOffset
 728 * @see #USEARCH_DONE
 729 * @stable ICU 2.4
 730 */
 731 U_STABLE int32_t U_EXPORT2 usearch_next(UStringSearch *strsrch,
 732                                           UErrorCode    *status);
 733
 734 /**
 735 * Returns the index of the previous point at which the string text matches
 736 * the search pattern, starting at the current position.
 737 * The iterator is adjusted so that its current
 738 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if
 739 * one was found.
 740 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
 741 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>
 742 * @param strsrch search iterator data struct
 743 * @param status for errors if it occurs
 744 * @return The index of the previous match before the current position,
 745 *         or <tt>USEARCH_DONE</tt> if there are no more matches.
 746 * @see #usearch_last
 747 * @see #usearch_getOffset
 748 * @see #USEARCH_DONE
 749 * @stable ICU 2.4
 750 */
 751 U_STABLE int32_t U_EXPORT2 usearch_previous(UStringSearch *strsrch,
 752                                               UErrorCode    *status);
 753
 754 /**
 755 * Reset the iteration.
 756 * Search will begin at the start of the text string if a forward iteration
 757 * is initiated before a backwards iteration. Otherwise if a backwards
 758 * iteration is initiated before a forwards iteration, the search will begin
 759 * at the end of the text string.
 760 * @param strsrch search iterator data struct
 761 * @see #usearch_first
 762 * @stable ICU 2.4
 763 */
 764 U_STABLE void U_EXPORT2 usearch_reset(UStringSearch *strsrch);
 765
 766 #ifndef U_HIDE_INTERNAL_API
 767 /**
 768   *  Simple forward search for the pattern, starting at a specified index,
 769   *     and 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  inseparable 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 suppress 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_search(UStringSearch *strsrch,
 822                                           int32_t        startIdx,
 823                                           int32_t        *matchStart,
 824                                           int32_t        *matchLimit,
 825                                           UErrorCode     *status);
 826
 827 /**
 828   *  Simple backwards search for the pattern, starting at a specified index,
 829   *     and using using a default set search options.
 830   *
 831   *  This is an experimental function, and is not an official part of the
 832   *      ICU API.
 833   *
 834   *  The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored.
 835   *
 836   *  The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and
 837   *  any Break Iterator are ignored.
 838   *
 839   *  Matches obey the following constraints:
 840   *
 841   *      Characters at the start or end positions of a match that are ignorable
 842   *      for collation are not included as part of the match, unless they
 843   *      are part of a combining sequence, as described below.
 844   *
 845   *      A match will not include a partial combining sequence.  Combining
 846   *      character sequences  are considered to be  inseparable units,
 847   *      and either match the pattern completely, or are considered to not match
 848   *      at all.  Thus, for example, an A followed a combining accent mark will
 849   *      not be found when searching for a plain (unaccented) A.   (unless
 850   *      the collation strength has been set to ignore all accents).
 851   *
 852   *      When beginning a search, the initial starting position, startIdx,
 853   *      is assumed to be an acceptable match boundary with respect to
 854   *      combining characters.  A combining sequence that spans across the
 855   *      starting point will not suppress a match beginning at startIdx.
 856   *
 857   *      Characters that expand to multiple collation elements
 858   *      (German sharp-S becoming 'ss', or the composed forms of accented
 859   *      characters, for example) also must match completely.
 860   *      Searching for a single 's' in a string containing only a sharp-s will
 861   *      find no match.
 862   *
 863   *
 864   *  @param strsrch    the UStringSearch struct, which references both
 865   *                    the text to be searched  and the pattern being sought.
 866   *  @param startIdx   The index into the text to begin the search.
 867   *  @param matchStart An out parameter, the starting index of the matched text.
 868   *                    This parameter may be NULL.
 869   *                    A value of -1 will be returned if no match was found.
 870   *  @param matchLimit Out parameter, the index of the first position following the matched text.
 871   *                    The matchLimit will be at a suitable position for beginning a subsequent search
 872   *                    in the input text.
 873   *                    This parameter may be NULL.
 874   *                    A value of -1 will be returned if no match was found.
 875   *
 876   *  @param status     Report any errors.  Note that no match found is not an error.
 877   *  @return           TRUE if a match was found, FALSE otherwise.
 878   *
 879   *  @internal
 880   */
 881 U_INTERNAL UBool U_EXPORT2 usearch_searchBackwards(UStringSearch *strsrch,
 882                                                    int32_t        startIdx,
 883                                                    int32_t        *matchStart,
 884                                                    int32_t        *matchLimit,
 885                                                    UErrorCode     *status);
 886 #endif  /* U_HIDE_INTERNAL_API */
 887
 888 #endif /* #if !UCONFIG_NO_COLLATION  && !UCONFIG_NO_BREAK_ITERATION */
 889
 890 #endif