1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 **********************************************************************
5 *   Copyright (C) 2004-2016, International Business Machines
6 *   Corporation and others.  All Rights Reserved.
7 **********************************************************************
8 *   file name:  uregex.h
9 *   encoding:   UTF-8
10 *   indentation:4
11 *
12 *   created on: 2004mar09
13 *   created by: Andy Heninger
14 *
15 *   ICU Regular Expressions, API for C
16 */
17 
18 /**
19  * \file
20  * \brief C API: Regular Expressions
21  *
22  * <p>This is a C wrapper around the C++ RegexPattern and RegexMatcher classes.</p>
23  */
24 
25 #ifndef UREGEX_H
26 #define UREGEX_H
27 
28 #include "unicode/utext.h"
29 #include "unicode/utypes.h"
30 
31 #if !UCONFIG_NO_REGULAR_EXPRESSIONS
32 
33 #include "unicode/localpointer.h"
34 #include "unicode/parseerr.h"
35 
36 struct URegularExpression;
37 /**
38   * Structure representing a compiled regular expression, plus the results
39   *    of a match operation.
40   * @stable ICU 3.0
41   */
42 typedef struct URegularExpression URegularExpression;
43 
44 
45 /**
46  * Constants for Regular Expression Match Modes.
47  * @stable ICU 2.4
48  */
49 typedef enum URegexpFlag{
50 
51 #ifndef U_HIDE_DRAFT_API
52     /** Forces normalization of pattern and strings.
53     Not implemented yet, just a placeholder, hence draft.
54     @draft ICU 2.4 */
55     UREGEX_CANON_EQ         = 128,
56 #endif /* U_HIDE_DRAFT_API */
57     /**  Enable case insensitive matching.  @stable ICU 2.4 */
58     UREGEX_CASE_INSENSITIVE = 2,
59 
60     /**  Allow white space and comments within patterns  @stable ICU 2.4 */
61     UREGEX_COMMENTS         = 4,
62 
63     /**  If set, '.' matches line terminators,  otherwise '.' matching stops at line end.
64       *  @stable ICU 2.4 */
65     UREGEX_DOTALL           = 32,
66 
67     /**  If set, treat the entire pattern as a literal string.
68       *  Metacharacters or escape sequences in the input sequence will be given
69       *  no special meaning.
70       *
71       *  The flag UREGEX_CASE_INSENSITIVE retains its impact
72       *  on matching when used in conjunction with this flag.
73       *  The other flags become superfluous.
74       *
75       * @stable ICU 4.0
76       */
77     UREGEX_LITERAL = 16,
78 
79     /**   Control behavior of "$" and "^"
80       *    If set, recognize line terminators within string,
81       *    otherwise, match only at start and end of input string.
82       *   @stable ICU 2.4 */
83     UREGEX_MULTILINE        = 8,
84 
85     /**   Unix-only line endings.
86       *   When this mode is enabled, only \\u000a is recognized as a line ending
87       *    in the behavior of ., ^, and $.
88       *   @stable ICU 4.0
89       */
90     UREGEX_UNIX_LINES = 1,
91 
92     /**  Unicode word boundaries.
93       *     If set, \b uses the Unicode TR 29 definition of word boundaries.
94       *     Warning: Unicode word boundaries are quite different from
95       *     traditional regular expression word boundaries.  See
96       *     http://unicode.org/reports/tr29/#Word_Boundaries
97       *     @stable ICU 2.8
98       */
99     UREGEX_UWORD            = 256,
100 
101      /**  Error on Unrecognized backslash escapes.
102        *     If set, fail with an error on patterns that contain
103        *     backslash-escaped ASCII letters without a known special
104        *     meaning.  If this flag is not set, these
105        *     escaped letters represent themselves.
106        *     @stable ICU 4.0
107        */
108      UREGEX_ERROR_ON_UNKNOWN_ESCAPES = 512
109 
110 }  URegexpFlag;
111 
112 /**
113   *  Open (compile) an ICU regular expression.  Compiles the regular expression in
114   *  string form into an internal representation using the specified match mode flags.
115   *  The resulting regular expression handle can then be used to perform various
116   *   matching operations.
117   *
118   *
119   * @param pattern        The Regular Expression pattern to be compiled.
120   * @param patternLength  The length of the pattern, or -1 if the pattern is
121   *                       NUL terminated.
122   * @param flags          Flags that alter the default matching behavior for
123   *                       the regular expression, UREGEX_CASE_INSENSITIVE, for
124   *                       example.  For default behavior, set this parameter to zero.
125   *                       See <code>enum URegexpFlag</code>.  All desired flags
126   *                       are bitwise-ORed together.
127   * @param pe             Receives the position (line and column numbers) of any syntax
128   *                       error within the source regular expression string.  If this
129   *                       information is not wanted, pass NULL for this parameter.
130   * @param status         Receives error detected by this function.
131   * @stable ICU 3.0
132   *
133   */
134 U_STABLE URegularExpression * U_EXPORT2
135 uregex_open( const  UChar          *pattern,
136                     int32_t         patternLength,
137                     uint32_t        flags,
138                     UParseError    *pe,
139                     UErrorCode     *status);
140 
141 /**
142   *  Open (compile) an ICU regular expression.  Compiles the regular expression in
143   *  string form into an internal representation using the specified match mode flags.
144   *  The resulting regular expression handle can then be used to perform various
145   *   matching operations.
146   *  <p>
147   *  The contents of the pattern UText will be extracted and saved. Ownership of the
148   *   UText struct itself remains with the caller. This is to match the behavior of
149   *   uregex_open().
150   *
151   * @param pattern        The Regular Expression pattern to be compiled.
152   * @param flags          Flags that alter the default matching behavior for
153   *                       the regular expression, UREGEX_CASE_INSENSITIVE, for
154   *                       example.  For default behavior, set this parameter to zero.
155   *                       See <code>enum URegexpFlag</code>.  All desired flags
156   *                       are bitwise-ORed together.
157   * @param pe             Receives the position (line and column numbers) of any syntax
158   *                       error within the source regular expression string.  If this
159   *                       information is not wanted, pass NULL for this parameter.
160   * @param status         Receives error detected by this function.
161   *
162   * @stable ICU 4.6
163   */
164 U_STABLE URegularExpression *  U_EXPORT2
165 uregex_openUText(UText          *pattern,
166                  uint32_t        flags,
167                  UParseError    *pe,
168                  UErrorCode     *status);
169 
170 #if !UCONFIG_NO_CONVERSION
171 /**
172   *  Open (compile) an ICU regular expression.  The resulting regular expression
173   *   handle can then be used to perform various matching operations.
174   *  <p>
175   *   This function is the same as uregex_open, except that the pattern
176   *   is supplied as an 8 bit char * string in the default code page.
177   *
178   * @param pattern        The Regular Expression pattern to be compiled,
179   *                       NUL terminated.
180   * @param flags          Flags that alter the default matching behavior for
181   *                       the regular expression, UREGEX_CASE_INSENSITIVE, for
182   *                       example.  For default behavior, set this parameter to zero.
183   *                       See <code>enum URegexpFlag</code>.  All desired flags
184   *                       are bitwise-ORed together.
185   * @param pe             Receives the position (line and column numbers) of any syntax
186   *                       error within the source regular expression string.  If this
187   *                       information is not wanted, pass NULL for this parameter.
188   * @param status         Receives errors detected by this function.
189   * @return               The URegularExpression object representing the compiled
190   *                       pattern.
191   *
192   * @stable ICU 3.0
193   */
194 U_STABLE URegularExpression * U_EXPORT2
195 uregex_openC( const char           *pattern,
196                     uint32_t        flags,
197                     UParseError    *pe,
198                     UErrorCode     *status);
199 #endif
200 
201 
202 
203 /**
204   *  Close the regular expression, recovering all resources (memory) it
205   *   was holding.
206   *
207   * @param regexp   The regular expression to be closed.
208   * @stable ICU 3.0
209   */
210 U_STABLE void U_EXPORT2
211 uregex_close(URegularExpression *regexp);
212 
213 #if U_SHOW_CPLUSPLUS_API
214 
215 U_NAMESPACE_BEGIN
216 
217 /**
218  * \class LocalURegularExpressionPointer
219  * "Smart pointer" class, closes a URegularExpression via uregex_close().
220  * For most methods see the LocalPointerBase base class.
221  *
222  * @see LocalPointerBase
223  * @see LocalPointer
224  * @stable ICU 4.4
225  */
226 U_DEFINE_LOCAL_OPEN_POINTER(LocalURegularExpressionPointer, URegularExpression, uregex_close);
227 
228 U_NAMESPACE_END
229 
230 #endif
231 
232 /**
233  * Make a copy of a compiled regular expression.  Cloning a regular
234  * expression is faster than opening a second instance from the source
235  * form of the expression, and requires less memory.
236  * <p>
237  * Note that the current input string and the position of any matched text
238  *  within it are not cloned; only the pattern itself and the
239  *  match mode flags are copied.
240  * <p>
241  * Cloning can be particularly useful to threaded applications that perform
242  * multiple match operations in parallel.  Each concurrent RE
243  * operation requires its own instance of a URegularExpression.
244  *
245  * @param regexp   The compiled regular expression to be cloned.
246  * @param status   Receives indication of any errors encountered
247  * @return the cloned copy of the compiled regular expression.
248  * @stable ICU 3.0
249  */
250 U_STABLE URegularExpression * U_EXPORT2
251 uregex_clone(const URegularExpression *regexp, UErrorCode *status);
252 
253 /**
254  *  Returns a pointer to the source form of the pattern for this regular expression.
255  *  This function will work even if the pattern was originally specified as a UText.
256  *
257  * @param regexp     The compiled regular expression.
258  * @param patLength  This output parameter will be set to the length of the
259  *                   pattern string.  A NULL pointer may be used here if the
260  *                   pattern length is not needed, as would be the case if
261  *                   the pattern is known in advance to be a NUL terminated
262  *                   string.
263  * @param status     Receives errors detected by this function.
264  * @return a pointer to the pattern string.  The storage for the string is
265  *                   owned by the regular expression object, and must not be
266  *                   altered or deleted by the application.  The returned string
267  *                   will remain valid until the regular expression is closed.
268  * @stable ICU 3.0
269  */
270 U_STABLE const UChar * U_EXPORT2
271 uregex_pattern(const URegularExpression *regexp,
272                      int32_t            *patLength,
273                      UErrorCode         *status);
274 
275 /**
276  *  Returns the source text of the pattern for this regular expression.
277  *  This function will work even if the pattern was originally specified as a UChar string.
278  *
279  * @param regexp     The compiled regular expression.
280  * @param status     Receives errors detected by this function.
281  * @return the pattern text.  The storage for the text is owned by the regular expression
282  *                   object, and must not be altered or deleted.
283  *
284  * @stable ICU 4.6
285  */
286 U_STABLE UText * U_EXPORT2
287 uregex_patternUText(const URegularExpression *regexp,
288                           UErrorCode         *status);
289 
290 /**
291   * Get the match mode flags that were specified when compiling this regular expression.
292   * @param status   Receives errors detected by this function.
293   * @param regexp   The compiled regular expression.
294   * @return         The match mode flags
295   * @see URegexpFlag
296   * @stable ICU 3.0
297   */
298 U_STABLE int32_t U_EXPORT2
299 uregex_flags(const  URegularExpression   *regexp,
300                     UErrorCode           *status);
301 
302 
303 /**
304   *  Set the subject text string upon which the regular expression will look for matches.
305   *  This function may be called any number of times, allowing the regular
306   *  expression pattern to be applied to different strings.
307   *  <p>
308   *  Regular expression matching operations work directly on the application's
309   *  string data.  No copy is made.  The subject string data must not be
310   *  altered after calling this function until after all regular expression
311   *  operations involving this string data are completed.
312   *  <p>
313   *  Zero length strings are permitted.  In this case, no subsequent match
314   *  operation will dereference the text string pointer.
315   *
316   * @param regexp     The compiled regular expression.
317   * @param text       The subject text string.
318   * @param textLength The length of the subject text, or -1 if the string
319   *                   is NUL terminated.
320   * @param status     Receives errors detected by this function.
321   * @stable ICU 3.0
322   */
323 U_STABLE void U_EXPORT2
324 uregex_setText(URegularExpression *regexp,
325                const UChar        *text,
326                int32_t             textLength,
327                UErrorCode         *status);
328 
329 
330 /**
331   *  Set the subject text string upon which the regular expression will look for matches.
332   *  This function may be called any number of times, allowing the regular
333   *  expression pattern to be applied to different strings.
334   *  <p>
335   *  Regular expression matching operations work directly on the application's
336   *  string data; only a shallow clone is made.  The subject string data must not be
337   *  altered after calling this function until after all regular expression
338   *  operations involving this string data are completed.
339   *
340   * @param regexp     The compiled regular expression.
341   * @param text       The subject text string.
342   * @param status     Receives errors detected by this function.
343   *
344   * @stable ICU 4.6
345   */
346 U_STABLE void U_EXPORT2
347 uregex_setUText(URegularExpression *regexp,
348                 UText              *text,
349                 UErrorCode         *status);
350 
351 /**
352   *  Get the subject text that is currently associated with this
353   *   regular expression object.  If the input was supplied using uregex_setText(),
354   *   that pointer will be returned.  Otherwise, the characters in the input will
355   *   be extracted to a buffer and returned.  In either case, ownership remains
356   *   with the regular expression object.
357   *
358   *  This function will work even if the input was originally specified as a UText.
359   *
360   * @param regexp      The compiled regular expression.
361   * @param textLength  The length of the string is returned in this output parameter.
362   *                    A NULL pointer may be used here if the
363   *                    text length is not needed, as would be the case if
364   *                    the text is known in advance to be a NUL terminated
365   *                    string.
366   * @param status      Receives errors detected by this function.
367   * @return            Pointer to the subject text string currently associated with
368   *                    this regular expression.
369   * @stable ICU 3.0
370   */
371 U_STABLE const UChar * U_EXPORT2
372 uregex_getText(URegularExpression *regexp,
373                int32_t            *textLength,
374                UErrorCode         *status);
375 
376 /**
377   *  Get the subject text that is currently associated with this
378   *   regular expression object.
379   *
380   *  This function will work even if the input was originally specified as a UChar string.
381   *
382   * @param regexp      The compiled regular expression.
383   * @param dest        A mutable UText in which to store the current input.
384   *                    If NULL, a new UText will be created as an immutable shallow clone
385   *                    of the actual input string.
386   * @param status      Receives errors detected by this function.
387   * @return            The subject text currently associated with this regular expression.
388   *                    If a pre-allocated UText was provided, it will always be used and returned.
389   *
390   * @stable ICU 4.6
391   */
392 U_STABLE UText * U_EXPORT2
393 uregex_getUText(URegularExpression *regexp,
394                 UText              *dest,
395                 UErrorCode         *status);
396 
397 /**
398   *  Set the subject text string upon which the regular expression is looking for matches
399   *  without changing any other aspect of the matching state.
400   *  The new and previous text strings must have the same content.
401   *
402   *  This function is intended for use in environments where ICU is operating on
403   *  strings that may move around in memory.  It provides a mechanism for notifying
404   *  ICU that the string has been relocated, and providing a new UText to access the
405   *  string in its new position.
406   *
407   *  Note that the regular expression implementation never copies the underlying text
408   *  of a string being matched, but always operates directly on the original text
409   *  provided by the user. Refreshing simply drops the references to the old text
410   *  and replaces them with references to the new.
411   *
412   *  Caution:  this function is normally used only by very specialized
413   *            system-level code.   One example use case is with garbage collection
414   *            that moves the text in memory.
415   *
416   * @param regexp     The compiled regular expression.
417   * @param text       The new (moved) text string.
418   * @param status     Receives errors detected by this function.
419   *
420   * @stable ICU 4.8
421   */
422 U_STABLE void U_EXPORT2
423 uregex_refreshUText(URegularExpression *regexp,
424                     UText              *text,
425                     UErrorCode         *status);
426 
427 /**
428   *   Attempts to match the input string against the pattern.
429   *   To succeed, the match must extend to the end of the string,
430   *   or cover the complete match region.
431   *
432   *   If startIndex >= zero the match operation starts at the specified
433   *   index and must extend to the end of the input string.  Any region
434   *   that has been specified is reset.
435   *
436   *   If startIndex == -1 the match must cover the input region, or the entire
437   *   input string if no region has been set.  This directly corresponds to
438   *   Matcher.matches() in Java
439   *
440   *    @param  regexp      The compiled regular expression.
441   *    @param  startIndex  The input string (native) index at which to begin matching, or -1
442   *                        to match the input Region.
443   *    @param  status      Receives errors detected by this function.
444   *    @return             TRUE if there is a match
445   *    @stable ICU 3.0
446   */
447 U_STABLE UBool U_EXPORT2
448 uregex_matches(URegularExpression *regexp,
449                 int32_t            startIndex,
450                 UErrorCode        *status);
451 
452 /**
453   *   64bit version of uregex_matches.
454   *   Attempts to match the input string against the pattern.
455   *   To succeed, the match must extend to the end of the string,
456   *   or cover the complete match region.
457   *
458   *   If startIndex >= zero the match operation starts at the specified
459   *   index and must extend to the end of the input string.  Any region
460   *   that has been specified is reset.
461   *
462   *   If startIndex == -1 the match must cover the input region, or the entire
463   *   input string if no region has been set.  This directly corresponds to
464   *   Matcher.matches() in Java
465   *
466   *    @param  regexp      The compiled regular expression.
467   *    @param  startIndex  The input string (native) index at which to begin matching, or -1
468   *                        to match the input Region.
469   *    @param  status      Receives errors detected by this function.
470   *    @return             TRUE if there is a match
471   *   @stable ICU 4.6
472   */
473 U_STABLE UBool U_EXPORT2
474 uregex_matches64(URegularExpression *regexp,
475                  int64_t            startIndex,
476                  UErrorCode        *status);
477 
478 /**
479   *   Attempts to match the input string, starting from the specified index, against the pattern.
480   *   The match may be of any length, and is not required to extend to the end
481   *   of the input string.  Contrast with uregex_matches().
482   *
483   *   <p>If startIndex is >= 0 any input region that was set for this
484   *   URegularExpression is reset before the operation begins.
485   *
486   *   <p>If the specified starting index == -1 the match begins at the start of the input
487   *   region, or at the start of the full string if no region has been specified.
488   *   This corresponds directly with Matcher.lookingAt() in Java.
489   *
490   *   <p>If the match succeeds then more information can be obtained via the
491   *    <code>uregexp_start()</code>, <code>uregexp_end()</code>,
492   *    and <code>uregex_group()</code> functions.</p>
493   *
494   *    @param   regexp      The compiled regular expression.
495   *    @param   startIndex  The input string (native) index at which to begin matching, or
496   *                         -1 to match the Input Region
497   *    @param   status      A reference to a UErrorCode to receive any errors.
498   *    @return  TRUE if there is a match.
499   *    @stable ICU 3.0
500   */
501 U_STABLE UBool U_EXPORT2
502 uregex_lookingAt(URegularExpression *regexp,
503                  int32_t             startIndex,
504                  UErrorCode         *status);
505 
506 /**
507   *   64bit version of uregex_lookingAt.
508   *   Attempts to match the input string, starting from the specified index, against the pattern.
509   *   The match may be of any length, and is not required to extend to the end
510   *   of the input string.  Contrast with uregex_matches().
511   *
512   *   <p>If startIndex is >= 0 any input region that was set for this
513   *   URegularExpression is reset before the operation begins.
514   *
515   *   <p>If the specified starting index == -1 the match begins at the start of the input
516   *   region, or at the start of the full string if no region has been specified.
517   *   This corresponds directly with Matcher.lookingAt() in Java.
518   *
519   *   <p>If the match succeeds then more information can be obtained via the
520   *    <code>uregexp_start()</code>, <code>uregexp_end()</code>,
521   *    and <code>uregex_group()</code> functions.</p>
522   *
523   *    @param   regexp      The compiled regular expression.
524   *    @param   startIndex  The input string (native) index at which to begin matching, or
525   *                         -1 to match the Input Region
526   *    @param   status      A reference to a UErrorCode to receive any errors.
527   *    @return  TRUE if there is a match.
528   *    @stable ICU 4.6
529   */
530 U_STABLE UBool U_EXPORT2
531 uregex_lookingAt64(URegularExpression *regexp,
532                    int64_t             startIndex,
533                    UErrorCode         *status);
534 
535 /**
536   *   Find the first matching substring of the input string that matches the pattern.
537   *   If startIndex is >= zero the search for a match begins at the specified index,
538   *          and any match region is reset.  This corresponds directly with
539   *          Matcher.find(startIndex) in Java.
540   *
541   *   If startIndex == -1 the search begins at the start of the input region,
542   *           or at the start of the full string if no region has been specified.
543   *
544   *   If a match is found, <code>uregex_start(), uregex_end()</code>, and
545   *   <code>uregex_group()</code> will provide more information regarding the match.
546   *
547   *   @param   regexp      The compiled regular expression.
548   *   @param   startIndex  The position (native) in the input string to begin the search, or
549   *                        -1 to search within the Input Region.
550   *   @param   status      A reference to a UErrorCode to receive any errors.
551   *   @return              TRUE if a match is found.
552   *   @stable ICU 3.0
553   */
554 U_STABLE UBool U_EXPORT2
555 uregex_find(URegularExpression *regexp,
556             int32_t             startIndex,
557             UErrorCode         *status);
558 
559 /**
560   *   64bit version of uregex_find.
561   *   Find the first matching substring of the input string that matches the pattern.
562   *   If startIndex is >= zero the search for a match begins at the specified index,
563   *          and any match region is reset.  This corresponds directly with
564   *          Matcher.find(startIndex) in Java.
565   *
566   *   If startIndex == -1 the search begins at the start of the input region,
567   *           or at the start of the full string if no region has been specified.
568   *
569   *   If a match is found, <code>uregex_start(), uregex_end()</code>, and
570   *   <code>uregex_group()</code> will provide more information regarding the match.
571   *
572   *   @param   regexp      The compiled regular expression.
573   *   @param   startIndex  The position (native) in the input string to begin the search, or
574   *                        -1 to search within the Input Region.
575   *   @param   status      A reference to a UErrorCode to receive any errors.
576   *   @return              TRUE if a match is found.
577   *   @stable ICU 4.6
578   */
579 U_STABLE UBool U_EXPORT2
580 uregex_find64(URegularExpression *regexp,
581               int64_t             startIndex,
582               UErrorCode         *status);
583 
584 /**
585   *  Find the next pattern match in the input string.  Begin searching
586   *  the input at the location following the end of he previous match,
587   *  or at the start of the string (or region) if there is no
588   *  previous match.  If a match is found, <code>uregex_start(), uregex_end()</code>, and
589   *  <code>uregex_group()</code> will provide more information regarding the match.
590   *
591   *  @param   regexp      The compiled regular expression.
592   *  @param   status      A reference to a UErrorCode to receive any errors.
593   *  @return              TRUE if a match is found.
594   *  @see uregex_reset
595   *  @stable ICU 3.0
596   */
597 U_STABLE UBool U_EXPORT2
598 uregex_findNext(URegularExpression *regexp,
599                 UErrorCode         *status);
600 
601 /**
602   *   Get the number of capturing groups in this regular expression's pattern.
603   *   @param   regexp      The compiled regular expression.
604   *   @param   status      A reference to a UErrorCode to receive any errors.
605   *   @return the number of capture groups
606   *   @stable ICU 3.0
607   */
608 U_STABLE int32_t U_EXPORT2
609 uregex_groupCount(URegularExpression *regexp,
610                   UErrorCode         *status);
611 
612 /**
613   * Get the group number corresponding to a named capture group.
614   * The returned number can be used with any function that access
615   * capture groups by number.
616   *
617   * The function returns an error status if the specified name does not
618   * appear in the pattern.
619   *
620   * @param  regexp      The compiled regular expression.
621   * @param  groupName   The capture group name.
622   * @param  nameLength  The length of the name, or -1 if the name is a
623   *                     nul-terminated string.
624   * @param  status      A pointer to a UErrorCode to receive any errors.
625   *
626   * @stable ICU 55
627   */
628 U_STABLE int32_t U_EXPORT2
629 uregex_groupNumberFromName(URegularExpression *regexp,
630                            const UChar        *groupName,
631                            int32_t             nameLength,
632                            UErrorCode          *status);
633 
634 
635 /**
636   * Get the group number corresponding to a named capture group.
637   * The returned number can be used with any function that access
638   * capture groups by number.
639   *
640   * The function returns an error status if the specified name does not
641   * appear in the pattern.
642   *
643   * @param  regexp      The compiled regular expression.
644   * @param  groupName   The capture group name,
645   *                     platform invariant characters only.
646   * @param  nameLength  The length of the name, or -1 if the name is
647   *                     nul-terminated.
648   * @param  status      A pointer to a UErrorCode to receive any errors.
649   *
650   * @stable ICU 55
651   */
652 U_STABLE int32_t U_EXPORT2
653 uregex_groupNumberFromCName(URegularExpression *regexp,
654                             const char         *groupName,
655                             int32_t             nameLength,
656                             UErrorCode          *status);
657 
658 /** Extract the string for the specified matching expression or subexpression.
659   * Group #0 is the complete string of matched text.
660   * Group #1 is the text matched by the first set of capturing parentheses.
661   *
662   *   @param   regexp       The compiled regular expression.
663   *   @param   groupNum     The capture group to extract.  Group 0 is the complete
664   *                         match.  The value of this parameter must be
665   *                         less than or equal to the number of capture groups in
666   *                         the pattern.
667   *   @param   dest         Buffer to receive the matching string data
668   *   @param   destCapacity Capacity of the dest buffer.
669   *   @param   status       A reference to a UErrorCode to receive any errors.
670   *   @return               Length of matching data,
671   *                         or -1 if no applicable match.
672   *   @stable ICU 3.0
673   */
674 U_STABLE int32_t U_EXPORT2
675 uregex_group(URegularExpression *regexp,
676              int32_t             groupNum,
677              UChar              *dest,
678              int32_t             destCapacity,
679              UErrorCode          *status);
680 
681 /** Returns a shallow immutable clone of the entire input string with the current index set
682   *   to the beginning of the requested capture group.  The capture group length is also
683   *   returned via groupLength.
684   * Group #0 is the complete string of matched text.
685   * Group #1 is the text matched by the first set of capturing parentheses.
686   *
687   *   @param   regexp       The compiled regular expression.
688   *   @param   groupNum     The capture group to extract.  Group 0 is the complete
689   *                         match.  The value of this parameter must be
690   *                         less than or equal to the number of capture groups in
691   *                         the pattern.
692   *   @param   dest         A mutable UText in which to store the current input.
693   *                         If NULL, a new UText will be created as an immutable shallow clone
694   *                         of the entire input string.
695   *   @param   groupLength  The group length of the desired capture group. Output parameter.
696   *   @param   status       A reference to a UErrorCode to receive any errors.
697   *   @return               The subject text currently associated with this regular expression.
698   *                         If a pre-allocated UText was provided, it will always be used and returned.
699 
700   *
701   *   @stable ICU 4.6
702   */
703 U_STABLE UText * U_EXPORT2
704 uregex_groupUText(URegularExpression *regexp,
705                   int32_t             groupNum,
706                   UText              *dest,
707                   int64_t            *groupLength,
708                   UErrorCode         *status);
709 
710 /**
711   *   Returns the index in the input string of the start of the text matched by the
712   *   specified capture group during the previous match operation.  Return -1 if
713   *   the capture group was not part of the last match.
714   *   Group #0 refers to the complete range of matched text.
715   *   Group #1 refers to the text matched by the first set of capturing parentheses.
716   *
717   *    @param   regexp      The compiled regular expression.
718   *    @param   groupNum    The capture group number
719   *    @param   status      A reference to a UErrorCode to receive any errors.
720   *    @return              the starting (native) position in the input of the text matched
721   *                         by the specified group.
722   *    @stable ICU 3.0
723   */
724 U_STABLE int32_t U_EXPORT2
725 uregex_start(URegularExpression *regexp,
726              int32_t             groupNum,
727              UErrorCode          *status);
728 
729 /**
730   *   64bit version of uregex_start.
731   *   Returns the index in the input string of the start of the text matched by the
732   *   specified capture group during the previous match operation.  Return -1 if
733   *   the capture group was not part of the last match.
734   *   Group #0 refers to the complete range of matched text.
735   *   Group #1 refers to the text matched by the first set of capturing parentheses.
736   *
737   *    @param   regexp      The compiled regular expression.
738   *    @param   groupNum    The capture group number
739   *    @param   status      A reference to a UErrorCode to receive any errors.
740   *    @return              the starting (native) position in the input of the text matched
741   *                         by the specified group.
742   *   @stable ICU 4.6
743   */
744 U_STABLE int64_t U_EXPORT2
745 uregex_start64(URegularExpression *regexp,
746                int32_t             groupNum,
747                UErrorCode          *status);
748 
749 /**
750   *   Returns the index in the input string of the position following the end
751   *   of the text matched by the specified capture group.
752   *   Return -1 if the capture group was not part of the last match.
753   *   Group #0 refers to the complete range of matched text.
754   *   Group #1 refers to the text matched by the first set of capturing parentheses.
755   *
756   *    @param   regexp      The compiled regular expression.
757   *    @param   groupNum    The capture group number
758   *    @param   status      A reference to a UErrorCode to receive any errors.
759   *    @return              the (native) index of the position following the last matched character.
760   *    @stable ICU 3.0
761   */
762 U_STABLE int32_t U_EXPORT2
763 uregex_end(URegularExpression   *regexp,
764            int32_t               groupNum,
765            UErrorCode           *status);
766 
767 /**
768   *   64bit version of uregex_end.
769   *   Returns the index in the input string of the position following the end
770   *   of the text matched by the specified capture group.
771   *   Return -1 if the capture group was not part of the last match.
772   *   Group #0 refers to the complete range of matched text.
773   *   Group #1 refers to the text matched by the first set of capturing parentheses.
774   *
775   *    @param   regexp      The compiled regular expression.
776   *    @param   groupNum    The capture group number
777   *    @param   status      A reference to a UErrorCode to receive any errors.
778   *    @return              the (native) index of the position following the last matched character.
779   *   @stable ICU 4.6
780   */
781 U_STABLE int64_t U_EXPORT2
782 uregex_end64(URegularExpression *regexp,
783              int32_t               groupNum,
784              UErrorCode           *status);
785 
786 /**
787   *  Reset any saved state from the previous match.  Has the effect of
788   *  causing uregex_findNext to begin at the specified index, and causing
789   *  uregex_start(), uregex_end() and uregex_group() to return an error
790   *  indicating that there is no match information available.  Clears any
791   *  match region that may have been set.
792   *
793   *    @param   regexp      The compiled regular expression.
794   *    @param   index       The position (native) in the text at which a
795   *                         uregex_findNext() should begin searching.
796   *    @param   status      A reference to a UErrorCode to receive any errors.
797   *    @stable ICU 3.0
798   */
799 U_STABLE void U_EXPORT2
800 uregex_reset(URegularExpression    *regexp,
801              int32_t               index,
802              UErrorCode            *status);
803 
804 /**
805   *  64bit version of uregex_reset.
806   *  Reset any saved state from the previous match.  Has the effect of
807   *  causing uregex_findNext to begin at the specified index, and causing
808   *  uregex_start(), uregex_end() and uregex_group() to return an error
809   *  indicating that there is no match information available.  Clears any
810   *  match region that may have been set.
811   *
812   *    @param   regexp      The compiled regular expression.
813   *    @param   index       The position (native) in the text at which a
814   *                         uregex_findNext() should begin searching.
815   *    @param   status      A reference to a UErrorCode to receive any errors.
816   *    @stable ICU 4.6
817   */
818 U_STABLE void U_EXPORT2
819 uregex_reset64(URegularExpression  *regexp,
820                int64_t               index,
821                UErrorCode            *status);
822 
823 /**
824   * Sets the limits of the matching region for this URegularExpression.
825   * The region is the part of the input string that will be considered when matching.
826   * Invoking this method resets any saved state from the previous match,
827   * then sets the region to start at the index specified by the start parameter
828   * and end at the index specified by the end parameter.
829   *
830   * Depending on the transparency and anchoring being used (see useTransparentBounds
831   * and useAnchoringBounds), certain constructs such as anchors may behave differently
832   * at or around the boundaries of the region
833   *
834   * The function will fail if start is greater than limit, or if either index
835   *  is less than zero or greater than the length of the string being matched.
836   *
837   * @param regexp The compiled regular expression.
838   * @param regionStart  The (native) index to begin searches at.
839   * @param regionLimit  The (native) index to end searches at (exclusive).
840   * @param status A pointer to a UErrorCode to receive any errors.
841   * @stable ICU 4.0
842   */
843 U_STABLE void U_EXPORT2
844 uregex_setRegion(URegularExpression   *regexp,
845                  int32_t               regionStart,
846                  int32_t               regionLimit,
847                  UErrorCode           *status);
848 
849 /**
850   * 64bit version of uregex_setRegion.
851   * Sets the limits of the matching region for this URegularExpression.
852   * The region is the part of the input string that will be considered when matching.
853   * Invoking this method resets any saved state from the previous match,
854   * then sets the region to start at the index specified by the start parameter
855   * and end at the index specified by the end parameter.
856   *
857   * Depending on the transparency and anchoring being used (see useTransparentBounds
858   * and useAnchoringBounds), certain constructs such as anchors may behave differently
859   * at or around the boundaries of the region
860   *
861   * The function will fail if start is greater than limit, or if either index
862   *  is less than zero or greater than the length of the string being matched.
863   *
864   * @param regexp The compiled regular expression.
865   * @param regionStart  The (native) index to begin searches at.
866   * @param regionLimit  The (native) index to end searches at (exclusive).
867   * @param status A pointer to a UErrorCode to receive any errors.
868   * @stable ICU 4.6
869   */
870 U_STABLE void U_EXPORT2
871 uregex_setRegion64(URegularExpression *regexp,
872                  int64_t               regionStart,
873                  int64_t               regionLimit,
874                  UErrorCode           *status);
875 
876 /**
877   *  Set the matching region and the starting index for subsequent matches
878   *  in a single operation.
879   *  This is useful because the usual function for setting the starting
880   *  index, urgex_reset(), also resets any region limits.
881   *
882   * @param regexp The compiled regular expression.
883   * @param regionStart  The (native) index to begin searches at.
884   * @param regionLimit  The (native) index to end searches at (exclusive).
885   * @param startIndex   The index in the input text at which the next
886   *                     match operation should begin.
887   * @param status A pointer to a UErrorCode to receive any errors.
888   * @stable ICU 4.6
889   */
890 U_STABLE void U_EXPORT2
891 uregex_setRegionAndStart(URegularExpression *regexp,
892                  int64_t               regionStart,
893                  int64_t               regionLimit,
894                  int64_t               startIndex,
895                  UErrorCode           *status);
896 
897 /**
898   * Reports the start index of the matching region. Any matches found are limited to
899   * to the region bounded by regionStart (inclusive) and regionEnd (exclusive).
900   *
901   * @param regexp The compiled regular expression.
902   * @param status A pointer to a UErrorCode to receive any errors.
903   * @return The starting (native) index of this matcher's region.
904   * @stable ICU 4.0
905   */
906 U_STABLE int32_t U_EXPORT2
907 uregex_regionStart(const  URegularExpression   *regexp,
908                           UErrorCode           *status);
909 
910 /**
911   * 64bit version of uregex_regionStart.
912   * Reports the start index of the matching region. Any matches found are limited to
913   * to the region bounded by regionStart (inclusive) and regionEnd (exclusive).
914   *
915   * @param regexp The compiled regular expression.
916   * @param status A pointer to a UErrorCode to receive any errors.
917   * @return The starting (native) index of this matcher's region.
918   * @stable ICU 4.6
919   */
920 U_STABLE int64_t U_EXPORT2
921 uregex_regionStart64(const  URegularExpression   *regexp,
922                             UErrorCode           *status);
923 
924 /**
925   * Reports the end index (exclusive) of the matching region for this URegularExpression.
926   * Any matches found are limited to to the region bounded by regionStart (inclusive)
927   * and regionEnd (exclusive).
928   *
929   * @param regexp The compiled regular expression.
930   * @param status A pointer to a UErrorCode to receive any errors.
931   * @return The ending point (native) of this matcher's region.
932   * @stable ICU 4.0
933   */
934 U_STABLE int32_t U_EXPORT2
935 uregex_regionEnd(const  URegularExpression   *regexp,
936                         UErrorCode           *status);
937 
938 /**
939   * 64bit version of uregex_regionEnd.
940   * Reports the end index (exclusive) of the matching region for this URegularExpression.
941   * Any matches found are limited to to the region bounded by regionStart (inclusive)
942   * and regionEnd (exclusive).
943   *
944   * @param regexp The compiled regular expression.
945   * @param status A pointer to a UErrorCode to receive any errors.
946   * @return The ending point (native) of this matcher's region.
947   * @stable ICU 4.6
948   */
949 U_STABLE int64_t U_EXPORT2
950 uregex_regionEnd64(const  URegularExpression   *regexp,
951                           UErrorCode           *status);
952 
953 /**
954   * Queries the transparency of region bounds for this URegularExpression.
955   * See useTransparentBounds for a description of transparent and opaque bounds.
956   * By default, matching boundaries are opaque.
957   *
958   * @param regexp The compiled regular expression.
959   * @param status A pointer to a UErrorCode to receive any errors.
960   * @return TRUE if this matcher is using opaque bounds, false if it is not.
961   * @stable ICU 4.0
962   */
963 U_STABLE UBool U_EXPORT2
964 uregex_hasTransparentBounds(const  URegularExpression   *regexp,
965                                    UErrorCode           *status);
966 
967 
968 /**
969   * Sets the transparency of region bounds for this URegularExpression.
970   * Invoking this function with an argument of TRUE will set matches to use transparent bounds.
971   * If the boolean argument is FALSE, then opaque bounds will be used.
972   *
973   * Using transparent bounds, the boundaries of the matching region are transparent
974   * to lookahead, lookbehind, and boundary matching constructs. Those constructs can
975   * see text beyond the boundaries of the region while checking for a match.
976   *
977   * With opaque bounds, no text outside of the matching region is visible to lookahead,
978   * lookbehind, and boundary matching constructs.
979   *
980   * By default, opaque bounds are used.
981   *
982   * @param   regexp The compiled regular expression.
983   * @param   b      TRUE for transparent bounds; FALSE for opaque bounds
984   * @param   status A pointer to a UErrorCode to receive any errors.
985   * @stable ICU 4.0
986   **/
987 U_STABLE void U_EXPORT2
988 uregex_useTransparentBounds(URegularExpression   *regexp,
989                             UBool                b,
990                             UErrorCode           *status);
991 
992 
993 /**
994   * Return true if this URegularExpression is using anchoring bounds.
995   * By default, anchoring region bounds are used.
996   *
997   * @param  regexp The compiled regular expression.
998   * @param  status A pointer to a UErrorCode to receive any errors.
999   * @return TRUE if this matcher is using anchoring bounds.
1000   * @stable ICU 4.0
1001   */
1002 U_STABLE UBool U_EXPORT2
1003 uregex_hasAnchoringBounds(const  URegularExpression   *regexp,
1004                                  UErrorCode           *status);
1005 
1006 
1007 /**
1008   * Set whether this URegularExpression is using Anchoring Bounds for its region.
1009   * With anchoring bounds, pattern anchors such as ^ and $ will match at the start
1010   * and end of the region.  Without Anchoring Bounds, anchors will only match at
1011   * the positions they would in the complete text.
1012   *
1013   * Anchoring Bounds are the default for regions.
1014   *
1015   * @param regexp The compiled regular expression.
1016   * @param b      TRUE if to enable anchoring bounds; FALSE to disable them.
1017   * @param status A pointer to a UErrorCode to receive any errors.
1018   * @stable ICU 4.0
1019   */
1020 U_STABLE void U_EXPORT2
1021 uregex_useAnchoringBounds(URegularExpression   *regexp,
1022                           UBool                 b,
1023                           UErrorCode           *status);
1024 
1025 /**
1026   * Return TRUE if the most recent matching operation touched the
1027   *  end of the text being processed.  In this case, additional input text could
1028   *  change the results of that match.
1029   *
1030   *  @param regexp The compiled regular expression.
1031   *  @param status A pointer to a UErrorCode to receive any errors.
1032   *  @return  TRUE if the most recent match hit the end of input
1033   *  @stable ICU 4.0
1034   */
1035 U_STABLE UBool U_EXPORT2
1036 uregex_hitEnd(const  URegularExpression   *regexp,
1037                      UErrorCode           *status);
1038 
1039 /**
1040   * Return TRUE the most recent match succeeded and additional input could cause
1041   * it to fail. If this function returns false and a match was found, then more input
1042   * might change the match but the match won't be lost. If a match was not found,
1043   * then requireEnd has no meaning.
1044   *
1045   * @param regexp The compiled regular expression.
1046   * @param status A pointer to a UErrorCode to receive any errors.
1047   * @return TRUE  if more input could cause the most recent match to no longer match.
1048   * @stable ICU 4.0
1049   */
1050 U_STABLE UBool U_EXPORT2
1051 uregex_requireEnd(const  URegularExpression   *regexp,
1052                          UErrorCode           *status);
1053 
1054 
1055 
1056 
1057 
1058 /**
1059   *    Replaces every substring of the input that matches the pattern
1060   *    with the given replacement string.  This is a convenience function that
1061   *    provides a complete find-and-replace-all operation.
1062   *
1063   *    This method scans the input string looking for matches of the pattern.
1064   *    Input that is not part of any match is copied unchanged to the
1065   *    destination buffer.  Matched regions are replaced in the output
1066   *    buffer by the replacement string.   The replacement string may contain
1067   *    references to capture groups; these take the form of $1, $2, etc.
1068   *
1069   *    @param   regexp             The compiled regular expression.
1070   *    @param   replacementText    A string containing the replacement text.
1071   *    @param   replacementLength  The length of the replacement string, or
1072   *                                -1 if it is NUL terminated.
1073   *    @param   destBuf            A (UChar *) buffer that will receive the result.
1074   *    @param   destCapacity       The capacity of the destination buffer.
1075   *    @param   status             A reference to a UErrorCode to receive any errors.
1076   *    @return                     The length of the string resulting from the find
1077   *                                and replace operation.  In the event that the
1078   *                                destination capacity is inadequate, the return value
1079   *                                is still the full length of the untruncated string.
1080   *    @stable ICU 3.0
1081   */
1082 U_STABLE int32_t U_EXPORT2
1083 uregex_replaceAll(URegularExpression    *regexp,
1084                   const UChar           *replacementText,
1085                   int32_t                replacementLength,
1086                   UChar                 *destBuf,
1087                   int32_t                destCapacity,
1088                   UErrorCode            *status);
1089 
1090 /**
1091   *    Replaces every substring of the input that matches the pattern
1092   *    with the given replacement string.  This is a convenience function that
1093   *    provides a complete find-and-replace-all operation.
1094   *
1095   *    This method scans the input string looking for matches of the pattern.
1096   *    Input that is not part of any match is copied unchanged to the
1097   *    destination buffer.  Matched regions are replaced in the output
1098   *    buffer by the replacement string.   The replacement string may contain
1099   *    references to capture groups; these take the form of $1, $2, etc.
1100   *
1101   *    @param   regexp         The compiled regular expression.
1102   *    @param   replacement    A string containing the replacement text.
1103   *    @param   dest           A mutable UText that will receive the result.
1104   *                             If NULL, a new UText will be created (which may not be mutable).
1105   *    @param   status         A reference to a UErrorCode to receive any errors.
1106   *    @return                 A UText containing the results of the find and replace.
1107   *                             If a pre-allocated UText was provided, it will always be used and returned.
1108   *
1109   *    @stable ICU 4.6
1110   */
1111 U_STABLE UText * U_EXPORT2
1112 uregex_replaceAllUText(URegularExpression *regexp,
1113                        UText              *replacement,
1114                        UText              *dest,
1115                        UErrorCode         *status);
1116 
1117 /**
1118   *    Replaces the first substring of the input that matches the pattern
1119   *    with the given replacement string.  This is a convenience function that
1120   *    provides a complete find-and-replace operation.
1121   *
1122   *    This method scans the input string looking for a match of the pattern.
1123   *    All input that is not part of the match is copied unchanged to the
1124   *    destination buffer.  The matched region is replaced in the output
1125   *    buffer by the replacement string.   The replacement string may contain
1126   *    references to capture groups; these take the form of $1, $2, etc.
1127   *
1128   *    @param   regexp             The compiled regular expression.
1129   *    @param   replacementText    A string containing the replacement text.
1130   *    @param   replacementLength  The length of the replacement string, or
1131   *                                -1 if it is NUL terminated.
1132   *    @param   destBuf            A (UChar *) buffer that will receive the result.
1133   *    @param   destCapacity       The capacity of the destination buffer.
1134   *    @param   status             a reference to a UErrorCode to receive any errors.
1135   *    @return                     The length of the string resulting from the find
1136   *                                and replace operation.  In the event that the
1137   *                                destination capacity is inadequate, the return value
1138   *                                is still the full length of the untruncated string.
1139   *    @stable ICU 3.0
1140   */
1141 U_STABLE int32_t U_EXPORT2
1142 uregex_replaceFirst(URegularExpression  *regexp,
1143                     const UChar         *replacementText,
1144                     int32_t              replacementLength,
1145                     UChar               *destBuf,
1146                     int32_t              destCapacity,
1147                     UErrorCode          *status);
1148 
1149 /**
1150   *    Replaces the first substring of the input that matches the pattern
1151   *    with the given replacement string.  This is a convenience function that
1152   *    provides a complete find-and-replace operation.
1153   *
1154   *    This method scans the input string looking for a match of the pattern.
1155   *    All input that is not part of the match is copied unchanged to the
1156   *    destination buffer.  The matched region is replaced in the output
1157   *    buffer by the replacement string.   The replacement string may contain
1158   *    references to capture groups; these take the form of $1, $2, etc.
1159   *
1160   *    @param   regexp         The compiled regular expression.
1161   *    @param   replacement    A string containing the replacement text.
1162   *    @param   dest           A mutable UText that will receive the result.
1163   *                             If NULL, a new UText will be created (which may not be mutable).
1164   *    @param   status         A reference to a UErrorCode to receive any errors.
1165   *    @return                 A UText containing the results of the find and replace.
1166   *                             If a pre-allocated UText was provided, it will always be used and returned.
1167   *
1168   *    @stable ICU 4.6
1169   */
1170 U_STABLE UText * U_EXPORT2
1171 uregex_replaceFirstUText(URegularExpression *regexp,
1172                          UText              *replacement,
1173                          UText              *dest,
1174                          UErrorCode         *status);
1175 
1176 /**
1177   *   Implements a replace operation intended to be used as part of an
1178   *   incremental find-and-replace.
1179   *
1180   *   <p>The input string, starting from the end of the previous match and ending at
1181   *   the start of the current match, is appended to the destination string.  Then the
1182   *   replacement string is appended to the output string,
1183   *   including handling any substitutions of captured text.</p>
1184   *
1185   *   <p>A note on preflight computation of buffersize and error handling:
1186   *   Calls to uregex_appendReplacement() and uregex_appendTail() are
1187   *   designed to be chained, one after another, with the destination
1188   *   buffer pointer and buffer capacity updated after each in preparation
1189   *   to for the next.  If the destination buffer is exhausted partway through such a
1190   *   sequence, a U_BUFFER_OVERFLOW_ERROR status will be returned.  Normal
1191   *   ICU conventions are for a function to perform no action if it is
1192   *   called with an error status, but for this one case, uregex_appendRepacement()
1193   *   will operate normally so that buffer size computations will complete
1194   *   correctly.
1195   *
1196   *   <p>For simple, prepackaged, non-incremental find-and-replace
1197   *      operations, see replaceFirst() or replaceAll().</p>
1198   *
1199   *   @param   regexp      The regular expression object.
1200   *   @param   replacementText The string that will replace the matched portion of the
1201   *                        input string as it is copied to the destination buffer.
1202   *                        The replacement text may contain references ($1, for
1203   *                        example) to capture groups from the match.
1204   *   @param   replacementLength  The length of the replacement text string,
1205   *                        or -1 if the string is NUL terminated.
1206   *   @param   destBuf     The buffer into which the results of the
1207   *                        find-and-replace are placed.  On return, this pointer
1208   *                        will be updated to refer to the beginning of the
1209   *                        unused portion of buffer, leaving it in position for
1210   *                        a subsequent call to this function.
1211   *   @param   destCapacity The size of the output buffer,  On return, this
1212   *                        parameter will be updated to reflect the space remaining
1213   *                        unused in the output buffer.
1214   *   @param   status      A reference to a UErrorCode to receive any errors.
1215   *   @return              The length of the result string.  In the event that
1216   *                        destCapacity is inadequate, the full length of the
1217   *                        untruncated output string is returned.
1218   *
1219   *   @stable ICU 3.0
1220   *
1221   */
1222 U_STABLE int32_t U_EXPORT2
1223 uregex_appendReplacement(URegularExpression    *regexp,
1224                          const UChar           *replacementText,
1225                          int32_t                replacementLength,
1226                          UChar                **destBuf,
1227                          int32_t               *destCapacity,
1228                          UErrorCode            *status);
1229 
1230 /**
1231   *   Implements a replace operation intended to be used as part of an
1232   *   incremental find-and-replace.
1233   *
1234   *   <p>The input string, starting from the end of the previous match and ending at
1235   *   the start of the current match, is appended to the destination string.  Then the
1236   *   replacement string is appended to the output string,
1237   *   including handling any substitutions of captured text.</p>
1238   *
1239   *   <p>For simple, prepackaged, non-incremental find-and-replace
1240   *      operations, see replaceFirst() or replaceAll().</p>
1241   *
1242   *   @param   regexp      The regular expression object.
1243   *   @param   replacementText The string that will replace the matched portion of the
1244   *                        input string as it is copied to the destination buffer.
1245   *                        The replacement text may contain references ($1, for
1246   *                        example) to capture groups from the match.
1247   *   @param   dest        A mutable UText that will receive the result. Must not be NULL.
1248   *   @param   status      A reference to a UErrorCode to receive any errors.
1249   *
1250   *   @stable ICU 4.6
1251   */
1252 U_STABLE void U_EXPORT2
1253 uregex_appendReplacementUText(URegularExpression    *regexp,
1254                               UText                 *replacementText,
1255                               UText                 *dest,
1256                               UErrorCode            *status);
1257 
1258 /**
1259   * As the final step in a find-and-replace operation, append the remainder
1260   * of the input string, starting at the position following the last match,
1261   * to the destination string. <code>uregex_appendTail()</code> is intended
1262   *  to be invoked after one or more invocations of the
1263   *  <code>uregex_appendReplacement()</code> function.
1264   *
1265   *   @param   regexp      The regular expression object.  This is needed to
1266   *                        obtain the input string and with the position
1267   *                        of the last match within it.
1268   *   @param   destBuf     The buffer in which the results of the
1269   *                        find-and-replace are placed.  On return, the pointer
1270   *                        will be updated to refer to the beginning of the
1271   *                        unused portion of buffer.
1272   *   @param   destCapacity The size of the output buffer,  On return, this
1273   *                        value will be updated to reflect the space remaining
1274   *                        unused in the output buffer.
1275   *   @param   status      A reference to a UErrorCode to receive any errors.
1276   *   @return              The length of the result string.  In the event that
1277   *                        destCapacity is inadequate, the full length of the
1278   *                        untruncated output string is returned.
1279   *
1280   *   @stable ICU 3.0
1281   */
1282 U_STABLE int32_t U_EXPORT2
1283 uregex_appendTail(URegularExpression    *regexp,
1284                   UChar                **destBuf,
1285                   int32_t               *destCapacity,
1286                   UErrorCode            *status);
1287 
1288 /**
1289   * As the final step in a find-and-replace operation, append the remainder
1290   * of the input string, starting at the position following the last match,
1291   * to the destination string. <code>uregex_appendTailUText()</code> is intended
1292   *  to be invoked after one or more invocations of the
1293   *  <code>uregex_appendReplacementUText()</code> function.
1294   *
1295   *   @param   regexp      The regular expression object.  This is needed to
1296   *                        obtain the input string and with the position
1297   *                        of the last match within it.
1298   *   @param   dest        A mutable UText that will receive the result. Must not be NULL.
1299   *
1300   *   @param status        Error code
1301   *
1302   *   @return              The destination UText.
1303   *
1304   *   @stable ICU 4.6
1305   */
1306 U_STABLE UText * U_EXPORT2
1307 uregex_appendTailUText(URegularExpression    *regexp,
1308                        UText                 *dest,
1309                        UErrorCode            *status);
1310 
1311  /**
1312    * Split a string into fields.  Somewhat like split() from Perl.
1313    *  The pattern matches identify delimiters that separate the input
1314    *  into fields.  The input data between the matches becomes the
1315    *  fields themselves.
1316    *
1317    *  Each of the fields is copied from the input string to the destination
1318    *  buffer, and NUL terminated.  The position of each field within
1319    *  the destination buffer is returned in the destFields array.
1320    *
1321    *  If the delimiter pattern includes capture groups, the captured text will
1322    *  also appear in the destination array of output strings, interspersed
1323    *  with the fields.  This is similar to Perl, but differs from Java,
1324    *  which ignores the presence of capture groups in the pattern.
1325    *
1326    *  Trailing empty fields will always be returned, assuming sufficient
1327    *  destination capacity.  This differs from the default behavior for Java
1328    *  and Perl where trailing empty fields are not returned.
1329    *
1330    *  The number of strings produced by the split operation is returned.
1331    *  This count includes the strings from capture groups in the delimiter pattern.
1332    *  This behavior differs from Java, which ignores capture groups.
1333    *
1334    *    @param   regexp      The compiled regular expression.
1335    *    @param   destBuf     A (UChar *) buffer to receive the fields that
1336    *                         are extracted from the input string. These
1337    *                         field pointers will refer to positions within the
1338    *                         destination buffer supplied by the caller.  Any
1339    *                         extra positions within the destFields array will be
1340    *                         set to NULL.
1341    *    @param   destCapacity The capacity of the destBuf.
1342    *    @param   requiredCapacity  The actual capacity required of the destBuf.
1343    *                         If destCapacity is too small, requiredCapacity will return
1344    *                         the total capacity required to hold all of the output, and
1345    *                         a U_BUFFER_OVERFLOW_ERROR will be returned.
1346    *    @param   destFields  An array to be filled with the position of each
1347    *                         of the extracted fields within destBuf.
1348    *    @param   destFieldsCapacity  The number of elements in the destFields array.
1349    *                If the number of fields found is less than destFieldsCapacity,
1350    *                the extra destFields elements are set to zero.
1351    *                If destFieldsCapacity is too small, the trailing part of the
1352    *                input, including any field delimiters, is treated as if it
1353    *                were the last field - it is copied to the destBuf, and
1354    *                its position is in the destBuf is stored in the last element
1355    *                of destFields.  This behavior mimics that of Perl.  It is not
1356    *                an error condition, and no error status is returned when all destField
1357    *                positions are used.
1358    * @param status  A reference to a UErrorCode to receive any errors.
1359    * @return        The number of fields into which the input string was split.
1360    * @stable ICU 3.0
1361    */
1362 U_STABLE int32_t U_EXPORT2
1363 uregex_split(   URegularExpression      *regexp,
1364                   UChar                 *destBuf,
1365                   int32_t                destCapacity,
1366                   int32_t               *requiredCapacity,
1367                   UChar                 *destFields[],
1368                   int32_t                destFieldsCapacity,
1369                   UErrorCode            *status);
1370 
1371   /**
1372    * Split a string into fields.  Somewhat like split() from Perl.
1373    * The pattern matches identify delimiters that separate the input
1374    *  into fields.  The input data between the matches becomes the
1375    *  fields themselves.
1376    * <p>
1377    * The behavior of this function is not very closely aligned with uregex_split();
1378    * instead, it is based on (and implemented directly on top of) the C++ split method.
1379    *
1380    * @param regexp  The compiled regular expression.
1381    * @param destFields    An array of mutable UText structs to receive the results of the split.
1382    *                If a field is NULL, a new UText is allocated to contain the results for
1383    *                that field. This new UText is not guaranteed to be mutable.
1384    * @param destFieldsCapacity  The number of elements in the destination array.
1385    *                If the number of fields found is less than destCapacity, the
1386    *                extra strings in the destination array are not altered.
1387    *                If the number of destination strings is less than the number
1388    *                of fields, the trailing part of the input string, including any
1389    *                field delimiters, is placed in the last destination string.
1390    *                This behavior mimics that of Perl.  It is not  an error condition, and no
1391    *                error status is returned when all destField positions are used.
1392    * @param status  A reference to a UErrorCode to receive any errors.
1393    * @return        The number of fields into which the input string was split.
1394    *
1395    * @stable ICU 4.6
1396    */
1397 U_STABLE int32_t U_EXPORT2
1398 uregex_splitUText(URegularExpression    *regexp,
1399                   UText                 *destFields[],
1400                   int32_t                destFieldsCapacity,
1401                   UErrorCode            *status);
1402 
1403 /**
1404  * Set a processing time limit for match operations with this URegularExpression.
1405  *
1406  * Some patterns, when matching certain strings, can run in exponential time.
1407  * For practical purposes, the match operation may appear to be in an
1408  * infinite loop.
1409  * When a limit is set a match operation will fail with an error if the
1410  * limit is exceeded.
1411  * <p>
1412  * The units of the limit are steps of the match engine.
1413  * Correspondence with actual processor time will depend on the speed
1414  * of the processor and the details of the specific pattern, but will
1415  * typically be on the order of milliseconds.
1416  * <p>
1417  * By default, the matching time is not limited.
1418  * <p>
1419  *
1420  * @param   regexp      The compiled regular expression.
1421  * @param   limit       The limit value, or 0 for no limit.
1422  * @param   status      A reference to a UErrorCode to receive any errors.
1423  * @stable ICU 4.0
1424  */
1425 U_STABLE void U_EXPORT2
1426 uregex_setTimeLimit(URegularExpression      *regexp,
1427                     int32_t                  limit,
1428                     UErrorCode              *status);
1429 
1430 /**
1431  * Get the time limit for for matches with this URegularExpression.
1432  * A return value of zero indicates that there is no limit.
1433  *
1434  * @param   regexp      The compiled regular expression.
1435  * @param   status      A reference to a UErrorCode to receive any errors.
1436  * @return the maximum allowed time for a match, in units of processing steps.
1437  * @stable ICU 4.0
1438  */
1439 U_STABLE int32_t U_EXPORT2
1440 uregex_getTimeLimit(const URegularExpression      *regexp,
1441                           UErrorCode              *status);
1442 
1443 /**
1444  * Set the amount of heap storage available for use by the match backtracking stack.
1445  * <p>
1446  * ICU uses a backtracking regular expression engine, with the backtrack stack
1447  * maintained on the heap.  This function sets the limit to the amount of memory
1448  * that can be used  for this purpose.  A backtracking stack overflow will
1449  * result in an error from the match operation that caused it.
1450  * <p>
1451  * A limit is desirable because a malicious or poorly designed pattern can use
1452  * excessive memory, potentially crashing the process.  A limit is enabled
1453  * by default.
1454  * <p>
1455  * @param   regexp      The compiled regular expression.
1456  * @param   limit       The maximum size, in bytes, of the matching backtrack stack.
1457  *                      A value of zero means no limit.
1458  *                      The limit must be greater than or equal to zero.
1459  * @param   status      A reference to a UErrorCode to receive any errors.
1460  *
1461  * @stable ICU 4.0
1462  */
1463 U_STABLE void U_EXPORT2
1464 uregex_setStackLimit(URegularExpression      *regexp,
1465                      int32_t                  limit,
1466                      UErrorCode              *status);
1467 
1468 /**
1469  * Get the size of the heap storage available for use by the back tracking stack.
1470  *
1471  * @return  the maximum backtracking stack size, in bytes, or zero if the
1472  *          stack size is unlimited.
1473  * @stable ICU 4.0
1474  */
1475 U_STABLE int32_t U_EXPORT2
1476 uregex_getStackLimit(const URegularExpression      *regexp,
1477                            UErrorCode              *status);
1478 
1479 
1480 /**
1481  * Function pointer for a regular expression matching callback function.
1482  * When set, a callback function will be called periodically during matching
1483  * operations.  If the call back function returns FALSE, the matching
1484  * operation will be terminated early.
1485  *
1486  * Note:  the callback function must not call other functions on this
1487  *        URegularExpression.
1488  *
1489  * @param context  context pointer.  The callback function will be invoked
1490  *                 with the context specified at the time that
1491  *                 uregex_setMatchCallback() is called.
1492  * @param steps    the accumulated processing time, in match steps,
1493  *                 for this matching operation.
1494  * @return         TRUE to continue the matching operation.
1495  *                 FALSE to terminate the matching operation.
1496  * @stable ICU 4.0
1497  */
1498 U_CDECL_BEGIN
1499 typedef UBool U_CALLCONV URegexMatchCallback (
1500                    const void *context,
1501                    int32_t     steps);
1502 U_CDECL_END
1503 
1504 /**
1505  * Set a callback function for this URegularExpression.
1506  * During matching operations the function will be called periodically,
1507  * giving the application the opportunity to terminate a long-running
1508  * match.
1509  *
1510  * @param   regexp      The compiled regular expression.
1511  * @param   callback    A pointer to the user-supplied callback function.
1512  * @param   context     User context pointer.  The value supplied at the
1513  *                      time the callback function is set will be saved
1514  *                      and passed to the callback each time that it is called.
1515  * @param   status      A reference to a UErrorCode to receive any errors.
1516  * @stable ICU 4.0
1517  */
1518 U_STABLE void U_EXPORT2
1519 uregex_setMatchCallback(URegularExpression      *regexp,
1520                         URegexMatchCallback     *callback,
1521                         const void              *context,
1522                         UErrorCode              *status);
1523 
1524 
1525 /**
1526  *  Get the callback function for this URegularExpression.
1527  *
1528  * @param   regexp      The compiled regular expression.
1529  * @param   callback    Out parameter, receives a pointer to the user-supplied
1530  *                      callback function.
1531  * @param   context     Out parameter, receives the user context pointer that
1532  *                      was set when uregex_setMatchCallback() was called.
1533  * @param   status      A reference to a UErrorCode to receive any errors.
1534  * @stable ICU 4.0
1535  */
1536 U_STABLE void U_EXPORT2
1537 uregex_getMatchCallback(const URegularExpression    *regexp,
1538                         URegexMatchCallback        **callback,
1539                         const void                 **context,
1540                         UErrorCode                  *status);
1541 
1542 /**
1543  * Function pointer for a regular expression find callback function.
1544  *
1545  * When set, a callback function will be called during a find operation
1546  * and for operations that depend on find, such as findNext, split and some replace
1547  * operations like replaceFirst.
1548  * The callback will usually be called after each attempt at a match, but this is not a
1549  * guarantee that the callback will be invoked at each character.  For finds where the
1550  * match engine is invoked at each character, this may be close to true, but less likely
1551  * for more optimized loops where the pattern is known to only start, and the match
1552  * engine invoked, at certain characters.
1553  * When invoked, this callback will specify the index at which a match operation is about
1554  * to be attempted, giving the application the opportunity to terminate a long-running
1555  * find operation.
1556  *
1557  * If the call back function returns FALSE, the find operation will be terminated early.
1558  *
1559  * Note:  the callback function must not call other functions on this
1560  *        URegularExpression
1561  *
1562  * @param context  context pointer.  The callback function will be invoked
1563  *                 with the context specified at the time that
1564  *                 uregex_setFindProgressCallback() is called.
1565  * @param matchIndex  the next index at which a match attempt will be attempted for this
1566  *                 find operation.  If this callback interrupts the search, this is the
1567  *                 index at which a find/findNext operation may be re-initiated.
1568  * @return         TRUE to continue the matching operation.
1569  *                 FALSE to terminate the matching operation.
1570  * @stable ICU 4.6
1571  */
1572 U_CDECL_BEGIN
1573 typedef UBool U_CALLCONV URegexFindProgressCallback (
1574                    const void *context,
1575                    int64_t     matchIndex);
1576 U_CDECL_END
1577 
1578 
1579 /**
1580  *  Set the find progress callback function for this URegularExpression.
1581  *
1582  * @param   regexp      The compiled regular expression.
1583  * @param   callback    A pointer to the user-supplied callback function.
1584  * @param   context     User context pointer.  The value supplied at the
1585  *                      time the callback function is set will be saved
1586  *                      and passed to the callback each time that it is called.
1587  * @param   status      A reference to a UErrorCode to receive any errors.
1588  * @stable ICU 4.6
1589  */
1590 U_STABLE void U_EXPORT2
1591 uregex_setFindProgressCallback(URegularExpression              *regexp,
1592                                 URegexFindProgressCallback      *callback,
1593                                 const void                      *context,
1594                                 UErrorCode                      *status);
1595 
1596 /**
1597  *  Get the find progress callback function for this URegularExpression.
1598  *
1599  * @param   regexp      The compiled regular expression.
1600  * @param   callback    Out parameter, receives a pointer to the user-supplied
1601  *                      callback function.
1602  * @param   context     Out parameter, receives the user context pointer that
1603  *                      was set when uregex_setFindProgressCallback() was called.
1604  * @param   status      A reference to a UErrorCode to receive any errors.
1605  * @stable ICU 4.6
1606  */
1607 U_STABLE void U_EXPORT2
1608 uregex_getFindProgressCallback(const URegularExpression          *regexp,
1609                                 URegexFindProgressCallback        **callback,
1610                                 const void                        **context,
1611                                 UErrorCode                        *status);
1612 
1613 #endif   /*  !UCONFIG_NO_REGULAR_EXPRESSIONS  */
1614 #endif   /*  UREGEX_H  */
1615