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 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