xref: /aosp_15_r20/external/cronet/third_party/icu/source/common/unicode/uniset.h (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 ***************************************************************************
5 * Copyright (C) 1999-2016, International Business Machines Corporation
6 * and others. All Rights Reserved.
7 ***************************************************************************
8 *   Date        Name        Description
9 *   10/20/99    alan        Creation.
10 ***************************************************************************
11 */
12 
13 #ifndef UNICODESET_H
14 #define UNICODESET_H
15 
16 #include "unicode/utypes.h"
17 
18 #if U_SHOW_CPLUSPLUS_API
19 
20 #include "unicode/ucpmap.h"
21 #include "unicode/unifilt.h"
22 #include "unicode/unistr.h"
23 #include "unicode/uset.h"
24 
25 /**
26  * \file
27  * \brief C++ API: Unicode Set
28  */
29 
30 U_NAMESPACE_BEGIN
31 
32 // Forward Declarations.
33 class BMPSet;
34 class ParsePosition;
35 class RBBIRuleScanner;
36 class SymbolTable;
37 class UnicodeSetStringSpan;
38 class UVector;
39 class RuleCharacterIterator;
40 
41 /**
42  * A mutable set of Unicode characters and multicharacter strings.  Objects of this class
43  * represent <em>character classes</em> used in regular expressions.
44  * A character specifies a subset of Unicode code points.  Legal
45  * code points are U+0000 to U+10FFFF, inclusive.
46  *
47  * <p>The UnicodeSet class is not designed to be subclassed.
48  *
49  * <p><code>UnicodeSet</code> supports two APIs. The first is the
50  * <em>operand</em> API that allows the caller to modify the value of
51  * a <code>UnicodeSet</code> object. It conforms to Java 2's
52  * <code>java.util.Set</code> interface, although
53  * <code>UnicodeSet</code> does not actually implement that
54  * interface. All methods of <code>Set</code> are supported, with the
55  * modification that they take a character range or single character
56  * instead of an <code>Object</code>, and they take a
57  * <code>UnicodeSet</code> instead of a <code>Collection</code>.  The
58  * operand API may be thought of in terms of boolean logic: a boolean
59  * OR is implemented by <code>add</code>, a boolean AND is implemented
60  * by <code>retain</code>, a boolean XOR is implemented by
61  * <code>complement</code> taking an argument, and a boolean NOT is
62  * implemented by <code>complement</code> with no argument.  In terms
63  * of traditional set theory function names, <code>add</code> is a
64  * union, <code>retain</code> is an intersection, <code>remove</code>
65  * is an asymmetric difference, and <code>complement</code> with no
66  * argument is a set complement with respect to the superset range
67  * <code>MIN_VALUE-MAX_VALUE</code>
68  *
69  * <p>The second API is the
70  * <code>applyPattern()</code>/<code>toPattern()</code> API from the
71  * <code>java.text.Format</code>-derived classes.  Unlike the
72  * methods that add characters, add categories, and control the logic
73  * of the set, the method <code>applyPattern()</code> sets all
74  * attributes of a <code>UnicodeSet</code> at once, based on a
75  * string pattern.
76  *
77  * <p><b>Pattern syntax</b></p>
78  *
79  * Patterns are accepted by the constructors and the
80  * <code>applyPattern()</code> methods and returned by the
81  * <code>toPattern()</code> method.  These patterns follow a syntax
82  * similar to that employed by version 8 regular expression character
83  * classes.  Here are some simple examples:
84  *
85  * \htmlonly<blockquote>\endhtmlonly
86  *   <table>
87  *     <tr align="top">
88  *       <td nowrap valign="top" align="left"><code>[]</code></td>
89  *       <td valign="top">No characters</td>
90  *     </tr><tr align="top">
91  *       <td nowrap valign="top" align="left"><code>[a]</code></td>
92  *       <td valign="top">The character 'a'</td>
93  *     </tr><tr align="top">
94  *       <td nowrap valign="top" align="left"><code>[ae]</code></td>
95  *       <td valign="top">The characters 'a' and 'e'</td>
96  *     </tr>
97  *     <tr>
98  *       <td nowrap valign="top" align="left"><code>[a-e]</code></td>
99  *       <td valign="top">The characters 'a' through 'e' inclusive, in Unicode code
100  *       point order</td>
101  *     </tr>
102  *     <tr>
103  *       <td nowrap valign="top" align="left"><code>[\\u4E01]</code></td>
104  *       <td valign="top">The character U+4E01</td>
105  *     </tr>
106  *     <tr>
107  *       <td nowrap valign="top" align="left"><code>[a{ab}{ac}]</code></td>
108  *       <td valign="top">The character 'a' and the multicharacter strings &quot;ab&quot; and
109  *       &quot;ac&quot;</td>
110  *     </tr>
111  *     <tr>
112  *       <td nowrap valign="top" align="left"><code>[\\p{Lu}]</code></td>
113  *       <td valign="top">All characters in the general category Uppercase Letter</td>
114  *     </tr>
115  *   </table>
116  * \htmlonly</blockquote>\endhtmlonly
117  *
118  * Any character may be preceded by a backslash in order to remove any special
119  * meaning.  White space characters, as defined by UCharacter.isWhitespace(), are
120  * ignored, unless they are escaped.
121  *
122  * <p>Property patterns specify a set of characters having a certain
123  * property as defined by the Unicode standard.  Both the POSIX-like
124  * "[:Lu:]" and the Perl-like syntax "\\p{Lu}" are recognized.  For a
125  * complete list of supported property patterns, see the User's Guide
126  * for UnicodeSet at
127  * <a href="https://unicode-org.github.io/icu/userguide/strings/unicodeset">
128  * https://unicode-org.github.io/icu/userguide/strings/unicodeset</a>.
129  * Actual determination of property data is defined by the underlying
130  * Unicode database as implemented by UCharacter.
131  *
132  * <p>Patterns specify individual characters, ranges of characters, and
133  * Unicode property sets.  When elements are concatenated, they
134  * specify their union.  To complement a set, place a '^' immediately
135  * after the opening '['.  Property patterns are inverted by modifying
136  * their delimiters; "[:^foo]" and "\\P{foo}".  In any other location,
137  * '^' has no special meaning.
138  *
139  * <p>Since ICU 70, "[^...]", "[:^foo]", "\\P{foo}", and "[:binaryProperty=No:]"
140  * perform a “code point complement” (all code points minus the original set),
141  * removing all multicharacter strings,
142  * equivalent to <code>.complement().removeAllStrings()</code>.
143  * The complement() API function continues to perform a
144  * symmetric difference with all code points and thus retains all multicharacter strings.
145  *
146  * <p>Ranges are indicated by placing two a '-' between two
147  * characters, as in "a-z".  This specifies the range of all
148  * characters from the left to the right, in Unicode order.  If the
149  * left character is greater than or equal to the
150  * right character it is a syntax error.  If a '-' occurs as the first
151  * character after the opening '[' or '[^', or if it occurs as the
152  * last character before the closing ']', then it is taken as a
153  * literal.  Thus "[a\-b]", "[-ab]", and "[ab-]" all indicate the same
154  * set of three characters, 'a', 'b', and '-'.
155  *
156  * <p>Sets may be intersected using the '&' operator or the asymmetric
157  * set difference may be taken using the '-' operator, for example,
158  * "[[:L:]&[\\u0000-\\u0FFF]]" indicates the set of all Unicode letters
159  * with values less than 4096.  Operators ('&' and '|') have equal
160  * precedence and bind left-to-right.  Thus
161  * "[[:L:]-[a-z]-[\\u0100-\\u01FF]]" is equivalent to
162  * "[[[:L:]-[a-z]]-[\\u0100-\\u01FF]]".  This only really matters for
163  * difference; intersection is commutative.
164  *
165  * <table>
166  * <tr valign=top><td nowrap><code>[a]</code><td>The set containing 'a'
167  * <tr valign=top><td nowrap><code>[a-z]</code><td>The set containing 'a'
168  * through 'z' and all letters in between, in Unicode order
169  * <tr valign=top><td nowrap><code>[^a-z]</code><td>The set containing
170  * all characters but 'a' through 'z',
171  * that is, U+0000 through 'a'-1 and 'z'+1 through U+10FFFF
172  * <tr valign=top><td nowrap><code>[[<em>pat1</em>][<em>pat2</em>]]</code>
173  * <td>The union of sets specified by <em>pat1</em> and <em>pat2</em>
174  * <tr valign=top><td nowrap><code>[[<em>pat1</em>]&[<em>pat2</em>]]</code>
175  * <td>The intersection of sets specified by <em>pat1</em> and <em>pat2</em>
176  * <tr valign=top><td nowrap><code>[[<em>pat1</em>]-[<em>pat2</em>]]</code>
177  * <td>The asymmetric difference of sets specified by <em>pat1</em> and
178  * <em>pat2</em>
179  * <tr valign=top><td nowrap><code>[:Lu:] or \\p{Lu}</code>
180  * <td>The set of characters having the specified
181  * Unicode property; in
182  * this case, Unicode uppercase letters
183  * <tr valign=top><td nowrap><code>[:^Lu:] or \\P{Lu}</code>
184  * <td>The set of characters <em>not</em> having the given
185  * Unicode property
186  * </table>
187  *
188  * <p><b>Formal syntax</b></p>
189  *
190  * \htmlonly<blockquote>\endhtmlonly
191  *   <table>
192  *     <tr align="top">
193  *       <td nowrap valign="top" align="right"><code>pattern :=&nbsp; </code></td>
194  *       <td valign="top"><code>('[' '^'? item* ']') |
195  *       property</code></td>
196  *     </tr>
197  *     <tr align="top">
198  *       <td nowrap valign="top" align="right"><code>item :=&nbsp; </code></td>
199  *       <td valign="top"><code>char | (char '-' char) | pattern-expr<br>
200  *       </code></td>
201  *     </tr>
202  *     <tr align="top">
203  *       <td nowrap valign="top" align="right"><code>pattern-expr :=&nbsp; </code></td>
204  *       <td valign="top"><code>pattern | pattern-expr pattern |
205  *       pattern-expr op pattern<br>
206  *       </code></td>
207  *     </tr>
208  *     <tr align="top">
209  *       <td nowrap valign="top" align="right"><code>op :=&nbsp; </code></td>
210  *       <td valign="top"><code>'&amp;' | '-'<br>
211  *       </code></td>
212  *     </tr>
213  *     <tr align="top">
214  *       <td nowrap valign="top" align="right"><code>special :=&nbsp; </code></td>
215  *       <td valign="top"><code>'[' | ']' | '-'<br>
216  *       </code></td>
217  *     </tr>
218  *     <tr align="top">
219  *       <td nowrap valign="top" align="right"><code>char :=&nbsp; </code></td>
220  *       <td valign="top"><em>any character that is not</em><code> special<br>
221  *       | ('\' </code><em>any character</em><code>)<br>
222  *       | ('\\u' hex hex hex hex)<br>
223  *       </code></td>
224  *     </tr>
225  *     <tr align="top">
226  *       <td nowrap valign="top" align="right"><code>hex :=&nbsp; </code></td>
227  *       <td valign="top"><code>'0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' |<br>
228  *       &nbsp;&nbsp;&nbsp;&nbsp;'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'a' | 'b' | 'c' | 'd' | 'e' | 'f'</code></td>
229  *     </tr>
230  *     <tr>
231  *       <td nowrap valign="top" align="right"><code>property :=&nbsp; </code></td>
232  *       <td valign="top"><em>a Unicode property set pattern</em></td>
233  *     </tr>
234  *   </table>
235  *   <br>
236  *   <table border="1">
237  *     <tr>
238  *       <td>Legend: <table>
239  *         <tr>
240  *           <td nowrap valign="top"><code>a := b</code></td>
241  *           <td width="20" valign="top">&nbsp; </td>
242  *           <td valign="top"><code>a</code> may be replaced by <code>b</code> </td>
243  *         </tr>
244  *         <tr>
245  *           <td nowrap valign="top"><code>a?</code></td>
246  *           <td valign="top"></td>
247  *           <td valign="top">zero or one instance of <code>a</code><br>
248  *           </td>
249  *         </tr>
250  *         <tr>
251  *           <td nowrap valign="top"><code>a*</code></td>
252  *           <td valign="top"></td>
253  *           <td valign="top">one or more instances of <code>a</code><br>
254  *           </td>
255  *         </tr>
256  *         <tr>
257  *           <td nowrap valign="top"><code>a | b</code></td>
258  *           <td valign="top"></td>
259  *           <td valign="top">either <code>a</code> or <code>b</code><br>
260  *           </td>
261  *         </tr>
262  *         <tr>
263  *           <td nowrap valign="top"><code>'a'</code></td>
264  *           <td valign="top"></td>
265  *           <td valign="top">the literal string between the quotes </td>
266  *         </tr>
267  *       </table>
268  *       </td>
269  *     </tr>
270  *   </table>
271  * \htmlonly</blockquote>\endhtmlonly
272  *
273  * <p>Note:
274  *  - Most UnicodeSet methods do not take a UErrorCode parameter because
275  *   there are usually very few opportunities for failure other than a shortage
276  *   of memory, error codes in low-level C++ string methods would be inconvenient,
277  *   and the error code as the last parameter (ICU convention) would prevent
278  *   the use of default parameter values.
279  *   Instead, such methods set the UnicodeSet into a "bogus" state
280  *   (see isBogus()) if an error occurs.
281  *
282  * @author Alan Liu
283  * @stable ICU 2.0
284  */
285 class U_COMMON_API UnicodeSet final : public UnicodeFilter {
286 private:
287     /**
288      * Enough for sets with few ranges.
289      * For example, White_Space has 10 ranges, list length 21.
290      */
291     static constexpr int32_t INITIAL_CAPACITY = 25;
292     // fFlags constant
293     static constexpr uint8_t kIsBogus = 1;  // This set is bogus (i.e. not valid)
294 
295     UChar32* list = stackList; // MUST be terminated with HIGH
296     int32_t capacity = INITIAL_CAPACITY; // capacity of list
297     int32_t len = 1; // length of list used; 1 <= len <= capacity
298     uint8_t fFlags = 0;         // Bit flag (see constants above)
299 
300     BMPSet *bmpSet = nullptr; // The set is frozen iff either bmpSet or stringSpan is not nullptr.
301     UChar32* buffer = nullptr; // internal buffer, may be nullptr
302     int32_t bufferCapacity = 0; // capacity of buffer
303 
304     /**
305      * The pattern representation of this set.  This may not be the
306      * most economical pattern.  It is the pattern supplied to
307      * applyPattern(), with variables substituted and whitespace
308      * removed.  For sets constructed without applyPattern(), or
309      * modified using the non-pattern API, this string will be empty,
310      * indicating that toPattern() must generate a pattern
311      * representation from the inversion list.
312      */
313     char16_t *pat = nullptr;
314     int32_t patLen = 0;
315 
316     UVector* strings = nullptr; // maintained in sorted order
317     UnicodeSetStringSpan *stringSpan = nullptr;
318 
319     /**
320      * Initial list array.
321      * Avoids some heap allocations, and list is never nullptr.
322      * Increases the object size a bit.
323      */
324     UChar32 stackList[INITIAL_CAPACITY];
325 
326 public:
327     /**
328      * Determine if this object contains a valid set.
329      * A bogus set has no value. It is different from an empty set.
330      * It can be used to indicate that no set value is available.
331      *
332      * @return true if the set is bogus/invalid, false otherwise
333      * @see setToBogus()
334      * @stable ICU 4.0
335      */
336     inline UBool isBogus(void) const;
337 
338     /**
339      * Make this UnicodeSet object invalid.
340      * The string will test true with isBogus().
341      *
342      * A bogus set has no value. It is different from an empty set.
343      * It can be used to indicate that no set value is available.
344      *
345      * This utility function is used throughout the UnicodeSet
346      * implementation to indicate that a UnicodeSet operation failed,
347      * and may be used in other functions,
348      * especially but not exclusively when such functions do not
349      * take a UErrorCode for simplicity.
350      *
351      * @see isBogus()
352      * @stable ICU 4.0
353      */
354     void setToBogus();
355 
356 public:
357 
358     enum {
359         /**
360          * Minimum value that can be stored in a UnicodeSet.
361          * @stable ICU 2.4
362          */
363         MIN_VALUE = 0,
364 
365         /**
366          * Maximum value that can be stored in a UnicodeSet.
367          * @stable ICU 2.4
368          */
369         MAX_VALUE = 0x10ffff
370     };
371 
372     //----------------------------------------------------------------
373     // Constructors &c
374     //----------------------------------------------------------------
375 
376 public:
377 
378     /**
379      * Constructs an empty set.
380      * @stable ICU 2.0
381      */
382     UnicodeSet();
383 
384     /**
385      * Constructs a set containing the given range. If <code>end <
386      * start</code> then an empty set is created.
387      *
388      * @param start first character, inclusive, of range
389      * @param end last character, inclusive, of range
390      * @stable ICU 2.4
391      */
392     UnicodeSet(UChar32 start, UChar32 end);
393 
394 #ifndef U_HIDE_INTERNAL_API
395     /**
396      * @internal
397      */
398     enum ESerialization {
399       kSerialized  /* result of serialize() */
400     };
401 
402     /**
403      * Constructs a set from the output of serialize().
404      *
405      * @param buffer the 16 bit array
406      * @param bufferLen the original length returned from serialize()
407      * @param serialization the value 'kSerialized'
408      * @param status error code
409      *
410      * @internal
411      */
412     UnicodeSet(const uint16_t buffer[], int32_t bufferLen,
413                ESerialization serialization, UErrorCode &status);
414 #endif  /* U_HIDE_INTERNAL_API */
415 
416     /**
417      * Constructs a set from the given pattern.  See the class
418      * description for the syntax of the pattern language.
419      * @param pattern a string specifying what characters are in the set
420      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
421      * contains a syntax error.
422      * @stable ICU 2.0
423      */
424     UnicodeSet(const UnicodeString& pattern,
425                UErrorCode& status);
426 
427 #ifndef U_HIDE_INTERNAL_API
428     /**
429      * Constructs a set from the given pattern.  See the class
430      * description for the syntax of the pattern language.
431      * @param pattern a string specifying what characters are in the set
432      * @param options bitmask for options to apply to the pattern.
433      * Valid options are USET_IGNORE_SPACE and
434      * at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
435      * These case options are mutually exclusive.
436      * @param symbols a symbol table mapping variable names to values
437      * and stand-in characters to UnicodeSets; may be nullptr
438      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
439      * contains a syntax error.
440      * @internal
441      */
442     UnicodeSet(const UnicodeString& pattern,
443                uint32_t options,
444                const SymbolTable* symbols,
445                UErrorCode& status);
446 #endif  /* U_HIDE_INTERNAL_API */
447 
448     /**
449      * Constructs a set from the given pattern.  See the class description
450      * for the syntax of the pattern language.
451      * @param pattern a string specifying what characters are in the set
452      * @param pos on input, the position in pattern at which to start parsing.
453      * On output, the position after the last character parsed.
454      * @param options bitmask for options to apply to the pattern.
455      * Valid options are USET_IGNORE_SPACE and
456      * at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
457      * These case options are mutually exclusive.
458      * @param symbols a symbol table mapping variable names to values
459      * and stand-in characters to UnicodeSets; may be nullptr
460      * @param status input-output error code
461      * @stable ICU 2.8
462      */
463     UnicodeSet(const UnicodeString& pattern, ParsePosition& pos,
464                uint32_t options,
465                const SymbolTable* symbols,
466                UErrorCode& status);
467 
468     /**
469      * Constructs a set that is identical to the given UnicodeSet.
470      * @stable ICU 2.0
471      */
472     UnicodeSet(const UnicodeSet& o);
473 
474     /**
475      * Destructs the set.
476      * @stable ICU 2.0
477      */
478     virtual ~UnicodeSet();
479 
480     /**
481      * Assigns this object to be a copy of another.
482      * A frozen set will not be modified.
483      * @stable ICU 2.0
484      */
485     UnicodeSet& operator=(const UnicodeSet& o);
486 
487     /**
488      * Compares the specified object with this set for equality.  Returns
489      * <tt>true</tt> if the two sets
490      * have the same size, and every member of the specified set is
491      * contained in this set (or equivalently, every member of this set is
492      * contained in the specified set).
493      *
494      * @param o set to be compared for equality with this set.
495      * @return <tt>true</tt> if the specified set is equal to this set.
496      * @stable ICU 2.0
497      */
498     virtual bool operator==(const UnicodeSet& o) const;
499 
500     /**
501      * Compares the specified object with this set for equality.  Returns
502      * <tt>true</tt> if the specified set is not equal to this set.
503      * @stable ICU 2.0
504      */
505     inline bool operator!=(const UnicodeSet& o) const;
506 
507     /**
508      * Returns a copy of this object.  All UnicodeFunctor objects have
509      * to support cloning in order to allow classes using
510      * UnicodeFunctors, such as Transliterator, to implement cloning.
511      * If this set is frozen, then the clone will be frozen as well.
512      * Use cloneAsThawed() for a mutable clone of a frozen set.
513      * @see cloneAsThawed
514      * @stable ICU 2.0
515      */
516     virtual UnicodeSet* clone() const override;
517 
518     /**
519      * Returns the hash code value for this set.
520      *
521      * @return the hash code value for this set.
522      * @see Object#hashCode()
523      * @stable ICU 2.0
524      */
525     virtual int32_t hashCode(void) const;
526 
527     /**
528      * Get a UnicodeSet pointer from a USet
529      *
530      * @param uset a USet (the ICU plain C type for UnicodeSet)
531      * @return the corresponding UnicodeSet pointer.
532      *
533      * @stable ICU 4.2
534      */
535     inline static UnicodeSet *fromUSet(USet *uset);
536 
537     /**
538      * Get a UnicodeSet pointer from a const USet
539      *
540      * @param uset a const USet (the ICU plain C type for UnicodeSet)
541      * @return the corresponding UnicodeSet pointer.
542      *
543      * @stable ICU 4.2
544      */
545     inline static const UnicodeSet *fromUSet(const USet *uset);
546 
547     /**
548      * Produce a USet * pointer for this UnicodeSet.
549      * USet is the plain C type for UnicodeSet
550      *
551      * @return a USet pointer for this UnicodeSet
552      * @stable ICU 4.2
553      */
554     inline USet *toUSet();
555 
556 
557     /**
558      * Produce a const USet * pointer for this UnicodeSet.
559      * USet is the plain C type for UnicodeSet
560      *
561      * @return a const USet pointer for this UnicodeSet
562      * @stable ICU 4.2
563      */
564     inline const USet * toUSet() const;
565 
566 
567     //----------------------------------------------------------------
568     // Freezable API
569     //----------------------------------------------------------------
570 
571     /**
572      * Determines whether the set has been frozen (made immutable) or not.
573      * See the ICU4J Freezable interface for details.
574      * @return true/false for whether the set has been frozen
575      * @see freeze
576      * @see cloneAsThawed
577      * @stable ICU 3.8
578      */
579     inline UBool isFrozen() const;
580 
581     /**
582      * Freeze the set (make it immutable).
583      * Once frozen, it cannot be unfrozen and is therefore thread-safe
584      * until it is deleted.
585      * See the ICU4J Freezable interface for details.
586      * Freezing the set may also make some operations faster, for example
587      * contains() and span().
588      * A frozen set will not be modified. (It remains frozen.)
589      * @return this set.
590      * @see isFrozen
591      * @see cloneAsThawed
592      * @stable ICU 3.8
593      */
594     UnicodeSet *freeze();
595 
596     /**
597      * Clone the set and make the clone mutable.
598      * See the ICU4J Freezable interface for details.
599      * @return the mutable clone
600      * @see freeze
601      * @see isFrozen
602      * @stable ICU 3.8
603      */
604     UnicodeSet *cloneAsThawed() const;
605 
606     //----------------------------------------------------------------
607     // Public API
608     //----------------------------------------------------------------
609 
610     /**
611      * Make this object represent the range `start - end`.
612      * If `start > end` then this object is set to an empty range.
613      * A frozen set will not be modified.
614      *
615      * @param start first character in the set, inclusive
616      * @param end last character in the set, inclusive
617      * @stable ICU 2.4
618      */
619     UnicodeSet& set(UChar32 start, UChar32 end);
620 
621     /**
622      * Return true if the given position, in the given pattern, appears
623      * to be the start of a UnicodeSet pattern.
624      * @stable ICU 2.4
625      */
626     static UBool resemblesPattern(const UnicodeString& pattern,
627                                   int32_t pos);
628 
629     /**
630      * Modifies this set to represent the set specified by the given
631      * pattern, ignoring Unicode Pattern_White_Space characters.
632      * See the class description for the syntax of the pattern language.
633      * A frozen set will not be modified.
634      * @param pattern a string specifying what characters are in the set
635      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
636      * contains a syntax error.
637      * <em> Empties the set passed before applying the pattern.</em>
638      * @return a reference to this
639      * @stable ICU 2.0
640      */
641     UnicodeSet& applyPattern(const UnicodeString& pattern,
642                              UErrorCode& status);
643 
644 #ifndef U_HIDE_INTERNAL_API
645     /**
646      * Modifies this set to represent the set specified by the given
647      * pattern, optionally ignoring Unicode Pattern_White_Space characters.
648      * See the class description for the syntax of the pattern language.
649      * A frozen set will not be modified.
650      * @param pattern a string specifying what characters are in the set
651      * @param options bitmask for options to apply to the pattern.
652      * Valid options are USET_IGNORE_SPACE and
653      * at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
654      * These case options are mutually exclusive.
655      * @param symbols a symbol table mapping variable names to
656      * values and stand-ins to UnicodeSets; may be nullptr
657      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
658      * contains a syntax error.
659      *<em> Empties the set passed before applying the pattern.</em>
660      * @return a reference to this
661      * @internal
662      */
663     UnicodeSet& applyPattern(const UnicodeString& pattern,
664                              uint32_t options,
665                              const SymbolTable* symbols,
666                              UErrorCode& status);
667 #endif  /* U_HIDE_INTERNAL_API */
668 
669     /**
670      * Parses the given pattern, starting at the given position.  The
671      * character at pattern.charAt(pos.getIndex()) must be '[', or the
672      * parse fails.  Parsing continues until the corresponding closing
673      * ']'.  If a syntax error is encountered between the opening and
674      * closing brace, the parse fails.  Upon return from a successful
675      * parse, the ParsePosition is updated to point to the character
676      * following the closing ']', and a StringBuffer containing a
677      * pairs list for the parsed pattern is returned.  This method calls
678      * itself recursively to parse embedded subpatterns.
679      *<em> Empties the set passed before applying the pattern.</em>
680      * A frozen set will not be modified.
681      *
682      * @param pattern the string containing the pattern to be parsed.
683      * The portion of the string from pos.getIndex(), which must be a
684      * '[', to the corresponding closing ']', is parsed.
685      * @param pos upon entry, the position at which to being parsing.
686      * The character at pattern.charAt(pos.getIndex()) must be a '['.
687      * Upon return from a successful parse, pos.getIndex() is either
688      * the character after the closing ']' of the parsed pattern, or
689      * pattern.length() if the closing ']' is the last character of
690      * the pattern string.
691      * @param options bitmask for options to apply to the pattern.
692      * Valid options are USET_IGNORE_SPACE and
693      * at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
694      * These case options are mutually exclusive.
695      * @param symbols a symbol table mapping variable names to
696      * values and stand-ins to UnicodeSets; may be nullptr
697      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
698      * contains a syntax error.
699      * @return a reference to this
700      * @stable ICU 2.8
701      */
702     UnicodeSet& applyPattern(const UnicodeString& pattern,
703                              ParsePosition& pos,
704                              uint32_t options,
705                              const SymbolTable* symbols,
706                              UErrorCode& status);
707 
708     /**
709      * Returns a string representation of this set.  If the result of
710      * calling this function is passed to a UnicodeSet constructor, it
711      * will produce another set that is equal to this one.
712      * A frozen set will not be modified.
713      * @param result the string to receive the rules.  Previous
714      * contents will be deleted.
715      * @param escapeUnprintable if true then convert unprintable
716      * character to their hex escape representations, \\uxxxx or
717      * \\Uxxxxxxxx.  Unprintable characters are those other than
718      * U+000A, U+0020..U+007E.
719      * @stable ICU 2.0
720      */
721     virtual UnicodeString& toPattern(UnicodeString& result,
722                                      UBool escapeUnprintable = false) const override;
723 
724     /**
725      * Modifies this set to contain those code points which have the given value
726      * for the given binary or enumerated property, as returned by
727      * u_getIntPropertyValue.  Prior contents of this set are lost.
728      * A frozen set will not be modified.
729      *
730      * @param prop a property in the range UCHAR_BIN_START..UCHAR_BIN_LIMIT-1
731      * or UCHAR_INT_START..UCHAR_INT_LIMIT-1
732      * or UCHAR_MASK_START..UCHAR_MASK_LIMIT-1.
733      *
734      * @param value a value in the range u_getIntPropertyMinValue(prop)..
735      * u_getIntPropertyMaxValue(prop), with one exception.  If prop is
736      * UCHAR_GENERAL_CATEGORY_MASK, then value should not be a UCharCategory, but
737      * rather a mask value produced by U_GET_GC_MASK().  This allows grouped
738      * categories such as [:L:] to be represented.
739      *
740      * @param ec error code input/output parameter
741      *
742      * @return a reference to this set
743      *
744      * @stable ICU 2.4
745      */
746     UnicodeSet& applyIntPropertyValue(UProperty prop,
747                                       int32_t value,
748                                       UErrorCode& ec);
749 
750     /**
751      * Modifies this set to contain those code points which have the
752      * given value for the given property.  Prior contents of this
753      * set are lost.
754      * A frozen set will not be modified.
755      *
756      * @param prop a property alias, either short or long.  The name is matched
757      * loosely.  See PropertyAliases.txt for names and a description of loose
758      * matching.  If the value string is empty, then this string is interpreted
759      * as either a General_Category value alias, a Script value alias, a binary
760      * property alias, or a special ID.  Special IDs are matched loosely and
761      * correspond to the following sets:
762      *
763      * "ANY" = [\\u0000-\\U0010FFFF],
764      * "ASCII" = [\\u0000-\\u007F],
765      * "Assigned" = [:^Cn:].
766      *
767      * @param value a value alias, either short or long.  The name is matched
768      * loosely.  See PropertyValueAliases.txt for names and a description of
769      * loose matching.  In addition to aliases listed, numeric values and
770      * canonical combining classes may be expressed numerically, e.g., ("nv",
771      * "0.5") or ("ccc", "220").  The value string may also be empty.
772      *
773      * @param ec error code input/output parameter
774      *
775      * @return a reference to this set
776      *
777      * @stable ICU 2.4
778      */
779     UnicodeSet& applyPropertyAlias(const UnicodeString& prop,
780                                    const UnicodeString& value,
781                                    UErrorCode& ec);
782 
783     /**
784      * Returns the number of elements in this set (its cardinality).
785      * Note than the elements of a set may include both individual
786      * codepoints and strings.
787      *
788      * This is slower than getRangeCount() because
789      * it counts the code points of all ranges.
790      *
791      * @return the number of elements in this set (its cardinality).
792      * @stable ICU 2.0
793      * @see getRangeCount
794      */
795     virtual int32_t size(void) const;
796 
797     /**
798      * Returns <tt>true</tt> if this set contains no elements.
799      *
800      * @return <tt>true</tt> if this set contains no elements.
801      * @stable ICU 2.0
802      */
803     virtual UBool isEmpty(void) const;
804 
805     /**
806      * @return true if this set contains multi-character strings or the empty string.
807      * @stable ICU 70
808      */
809     UBool hasStrings() const;
810 
811     /**
812      * Returns true if this set contains the given character.
813      * This function works faster with a frozen set.
814      * @param c character to be checked for containment
815      * @return true if the test condition is met
816      * @stable ICU 2.0
817      */
818     virtual UBool contains(UChar32 c) const override;
819 
820     /**
821      * Returns true if this set contains every character
822      * of the given range.
823      * @param start first character, inclusive, of the range
824      * @param end last character, inclusive, of the range
825      * @return true if the test condition is met
826      * @stable ICU 2.0
827      */
828     virtual UBool contains(UChar32 start, UChar32 end) const;
829 
830     /**
831      * Returns <tt>true</tt> if this set contains the given
832      * multicharacter string.
833      * @param s string to be checked for containment
834      * @return <tt>true</tt> if this set contains the specified string
835      * @stable ICU 2.4
836      */
837     UBool contains(const UnicodeString& s) const;
838 
839     /**
840      * Returns true if this set contains all the characters and strings
841      * of the given set.
842      * @param c set to be checked for containment
843      * @return true if the test condition is met
844      * @stable ICU 2.4
845      */
846     virtual UBool containsAll(const UnicodeSet& c) const;
847 
848     /**
849      * Returns true if this set contains all the characters
850      * of the given string.
851      * @param s string containing characters to be checked for containment
852      * @return true if the test condition is met
853      * @stable ICU 2.4
854      */
855     UBool containsAll(const UnicodeString& s) const;
856 
857     /**
858      * Returns true if this set contains none of the characters
859      * of the given range.
860      * @param start first character, inclusive, of the range
861      * @param end last character, inclusive, of the range
862      * @return true if the test condition is met
863      * @stable ICU 2.4
864      */
865     UBool containsNone(UChar32 start, UChar32 end) const;
866 
867     /**
868      * Returns true if this set contains none of the characters and strings
869      * of the given set.
870      * @param c set to be checked for containment
871      * @return true if the test condition is met
872      * @stable ICU 2.4
873      */
874     UBool containsNone(const UnicodeSet& c) const;
875 
876     /**
877      * Returns true if this set contains none of the characters
878      * of the given string.
879      * @param s string containing characters to be checked for containment
880      * @return true if the test condition is met
881      * @stable ICU 2.4
882      */
883     UBool containsNone(const UnicodeString& s) const;
884 
885     /**
886      * Returns true if this set contains one or more of the characters
887      * in the given range.
888      * @param start first character, inclusive, of the range
889      * @param end last character, inclusive, of the range
890      * @return true if the condition is met
891      * @stable ICU 2.4
892      */
893     inline UBool containsSome(UChar32 start, UChar32 end) const;
894 
895     /**
896      * Returns true if this set contains one or more of the characters
897      * and strings of the given set.
898      * @param s The set to be checked for containment
899      * @return true if the condition is met
900      * @stable ICU 2.4
901      */
902     inline UBool containsSome(const UnicodeSet& s) const;
903 
904     /**
905      * Returns true if this set contains one or more of the characters
906      * of the given string.
907      * @param s string containing characters to be checked for containment
908      * @return true if the condition is met
909      * @stable ICU 2.4
910      */
911     inline UBool containsSome(const UnicodeString& s) const;
912 
913     /**
914      * Returns the length of the initial substring of the input string which
915      * consists only of characters and strings that are contained in this set
916      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
917      * or only of characters and strings that are not contained
918      * in this set (USET_SPAN_NOT_CONTAINED).
919      * See USetSpanCondition for details.
920      * Similar to the strspn() C library function.
921      * Unpaired surrogates are treated according to contains() of their surrogate code points.
922      * This function works faster with a frozen set and with a non-negative string length argument.
923      * @param s start of the string
924      * @param length of the string; can be -1 for NUL-terminated
925      * @param spanCondition specifies the containment condition
926      * @return the length of the initial substring according to the spanCondition;
927      *         0 if the start of the string does not fit the spanCondition
928      * @stable ICU 3.8
929      * @see USetSpanCondition
930      */
931     int32_t span(const char16_t *s, int32_t length, USetSpanCondition spanCondition) const;
932 
933     /**
934      * Returns the end of the substring of the input string according to the USetSpanCondition.
935      * Same as <code>start+span(s.getBuffer()+start, s.length()-start, spanCondition)</code>
936      * after pinning start to 0<=start<=s.length().
937      * @param s the string
938      * @param start the start index in the string for the span operation
939      * @param spanCondition specifies the containment condition
940      * @return the exclusive end of the substring according to the spanCondition;
941      *         the substring s.tempSubStringBetween(start, end) fulfills the spanCondition
942      * @stable ICU 4.4
943      * @see USetSpanCondition
944      */
945     inline int32_t span(const UnicodeString &s, int32_t start, USetSpanCondition spanCondition) const;
946 
947     /**
948      * Returns the start of the trailing substring of the input string which
949      * consists only of characters and strings that are contained in this set
950      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
951      * or only of characters and strings that are not contained
952      * in this set (USET_SPAN_NOT_CONTAINED).
953      * See USetSpanCondition for details.
954      * Unpaired surrogates are treated according to contains() of their surrogate code points.
955      * This function works faster with a frozen set and with a non-negative string length argument.
956      * @param s start of the string
957      * @param length of the string; can be -1 for NUL-terminated
958      * @param spanCondition specifies the containment condition
959      * @return the start of the trailing substring according to the spanCondition;
960      *         the string length if the end of the string does not fit the spanCondition
961      * @stable ICU 3.8
962      * @see USetSpanCondition
963      */
964     int32_t spanBack(const char16_t *s, int32_t length, USetSpanCondition spanCondition) const;
965 
966     /**
967      * Returns the start of the substring of the input string according to the USetSpanCondition.
968      * Same as <code>spanBack(s.getBuffer(), limit, spanCondition)</code>
969      * after pinning limit to 0<=end<=s.length().
970      * @param s the string
971      * @param limit the exclusive-end index in the string for the span operation
972      *              (use s.length() or INT32_MAX for spanning back from the end of the string)
973      * @param spanCondition specifies the containment condition
974      * @return the start of the substring according to the spanCondition;
975      *         the substring s.tempSubStringBetween(start, limit) fulfills the spanCondition
976      * @stable ICU 4.4
977      * @see USetSpanCondition
978      */
979     inline int32_t spanBack(const UnicodeString &s, int32_t limit, USetSpanCondition spanCondition) const;
980 
981     /**
982      * Returns the length of the initial substring of the input string which
983      * consists only of characters and strings that are contained in this set
984      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
985      * or only of characters and strings that are not contained
986      * in this set (USET_SPAN_NOT_CONTAINED).
987      * See USetSpanCondition for details.
988      * Similar to the strspn() C library function.
989      * Malformed byte sequences are treated according to contains(0xfffd).
990      * This function works faster with a frozen set and with a non-negative string length argument.
991      * @param s start of the string (UTF-8)
992      * @param length of the string; can be -1 for NUL-terminated
993      * @param spanCondition specifies the containment condition
994      * @return the length of the initial substring according to the spanCondition;
995      *         0 if the start of the string does not fit the spanCondition
996      * @stable ICU 3.8
997      * @see USetSpanCondition
998      */
999     int32_t spanUTF8(const char *s, int32_t length, USetSpanCondition spanCondition) const;
1000 
1001     /**
1002      * Returns the start of the trailing substring of the input string which
1003      * consists only of characters and strings that are contained in this set
1004      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
1005      * or only of characters and strings that are not contained
1006      * in this set (USET_SPAN_NOT_CONTAINED).
1007      * See USetSpanCondition for details.
1008      * Malformed byte sequences are treated according to contains(0xfffd).
1009      * This function works faster with a frozen set and with a non-negative string length argument.
1010      * @param s start of the string (UTF-8)
1011      * @param length of the string; can be -1 for NUL-terminated
1012      * @param spanCondition specifies the containment condition
1013      * @return the start of the trailing substring according to the spanCondition;
1014      *         the string length if the end of the string does not fit the spanCondition
1015      * @stable ICU 3.8
1016      * @see USetSpanCondition
1017      */
1018     int32_t spanBackUTF8(const char *s, int32_t length, USetSpanCondition spanCondition) const;
1019 
1020     /**
1021      * Implement UnicodeMatcher::matches()
1022      * @stable ICU 2.4
1023      */
1024     virtual UMatchDegree matches(const Replaceable& text,
1025                          int32_t& offset,
1026                          int32_t limit,
1027                          UBool incremental) override;
1028 
1029 private:
1030     /**
1031      * Returns the longest match for s in text at the given position.
1032      * If limit > start then match forward from start+1 to limit
1033      * matching all characters except s.charAt(0).  If limit < start,
1034      * go backward starting from start-1 matching all characters
1035      * except s.charAt(s.length()-1).  This method assumes that the
1036      * first character, text.charAt(start), matches s, so it does not
1037      * check it.
1038      * @param text the text to match
1039      * @param start the first character to match.  In the forward
1040      * direction, text.charAt(start) is matched against s.charAt(0).
1041      * In the reverse direction, it is matched against
1042      * s.charAt(s.length()-1).
1043      * @param limit the limit offset for matching, either last+1 in
1044      * the forward direction, or last-1 in the reverse direction,
1045      * where last is the index of the last character to match.
1046      * @param s
1047      * @return If part of s matches up to the limit, return |limit -
1048      * start|.  If all of s matches before reaching the limit, return
1049      * s.length().  If there is a mismatch between s and text, return
1050      * 0
1051      */
1052     static int32_t matchRest(const Replaceable& text,
1053                              int32_t start, int32_t limit,
1054                              const UnicodeString& s);
1055 
1056     /**
1057      * Returns the smallest value i such that c < list[i].  Caller
1058      * must ensure that c is a legal value or this method will enter
1059      * an infinite loop.  This method performs a binary search.
1060      * @param c a character in the range MIN_VALUE..MAX_VALUE
1061      * inclusive
1062      * @return the smallest integer i in the range 0..len-1,
1063      * inclusive, such that c < list[i]
1064      */
1065     int32_t findCodePoint(UChar32 c) const;
1066 
1067 public:
1068 
1069     /**
1070      * Implementation of UnicodeMatcher API.  Union the set of all
1071      * characters that may be matched by this object into the given
1072      * set.
1073      * @param toUnionTo the set into which to union the source characters
1074      * @stable ICU 2.4
1075      */
1076     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const override;
1077 
1078     /**
1079      * Returns the index of the given character within this set, where
1080      * the set is ordered by ascending code point.  If the character
1081      * is not in this set, return -1.  The inverse of this method is
1082      * <code>charAt()</code>.
1083      * @return an index from 0..size()-1, or -1
1084      * @stable ICU 2.4
1085      */
1086     int32_t indexOf(UChar32 c) const;
1087 
1088     /**
1089      * Returns the character at the given index within this set, where
1090      * the set is ordered by ascending code point.  If the index is
1091      * out of range for characters, returns (UChar32)-1.
1092      * The inverse of this method is <code>indexOf()</code>.
1093      *
1094      * For iteration, this is slower than UnicodeSetIterator or
1095      * getRangeCount()/getRangeStart()/getRangeEnd(),
1096      * because for each call it skips linearly over <code>index</code>
1097      * characters in the ranges.
1098      *
1099      * @param index an index from 0..size()-1
1100      * @return the character at the given index, or (UChar32)-1.
1101      * @stable ICU 2.4
1102      */
1103     UChar32 charAt(int32_t index) const;
1104 
1105     /**
1106      * Adds the specified range to this set if it is not already
1107      * present.  If this set already contains the specified range,
1108      * the call leaves this set unchanged.  If <code>start > end</code>
1109      * then an empty range is added, leaving the set unchanged.
1110      * This is equivalent to a boolean logic OR, or a set UNION.
1111      * A frozen set will not be modified.
1112      *
1113      * @param start first character, inclusive, of range to be added
1114      * to this set.
1115      * @param end last character, inclusive, of range to be added
1116      * to this set.
1117      * @stable ICU 2.0
1118      */
1119     virtual UnicodeSet& add(UChar32 start, UChar32 end);
1120 
1121     /**
1122      * Adds the specified character to this set if it is not already
1123      * present.  If this set already contains the specified character,
1124      * the call leaves this set unchanged.
1125      * A frozen set will not be modified.
1126      *
1127      * @param c the character (code point)
1128      * @return this object, for chaining
1129      * @stable ICU 2.0
1130      */
1131     UnicodeSet& add(UChar32 c);
1132 
1133     /**
1134      * Adds the specified multicharacter to this set if it is not already
1135      * present.  If this set already contains the multicharacter,
1136      * the call leaves this set unchanged.
1137      * Thus "ch" => {"ch"}
1138      * A frozen set will not be modified.
1139      *
1140      * @param s the source string
1141      * @return this object, for chaining
1142      * @stable ICU 2.4
1143      */
1144     UnicodeSet& add(const UnicodeString& s);
1145 
1146  private:
1147     /**
1148      * @return a code point IF the string consists of a single one.
1149      * otherwise returns -1.
1150      * @param s string to test
1151      */
1152     static int32_t getSingleCP(const UnicodeString& s);
1153 
1154     void _add(const UnicodeString& s);
1155 
1156  public:
1157     /**
1158      * Adds each of the characters in this string to the set. Note: "ch" => {"c", "h"}
1159      * If this set already contains any particular character, it has no effect on that character.
1160      * A frozen set will not be modified.
1161      * @param s the source string
1162      * @return this object, for chaining
1163      * @stable ICU 2.4
1164      */
1165     UnicodeSet& addAll(const UnicodeString& s);
1166 
1167     /**
1168      * Retains EACH of the characters in this string. Note: "ch" == {"c", "h"}
1169      * A frozen set will not be modified.
1170      * @param s the source string
1171      * @return this object, for chaining
1172      * @stable ICU 2.4
1173      */
1174     UnicodeSet& retainAll(const UnicodeString& s);
1175 
1176     /**
1177      * Complement EACH of the characters in this string. Note: "ch" == {"c", "h"}
1178      * A frozen set will not be modified.
1179      * @param s the source string
1180      * @return this object, for chaining
1181      * @stable ICU 2.4
1182      */
1183     UnicodeSet& complementAll(const UnicodeString& s);
1184 
1185     /**
1186      * Remove EACH of the characters in this string. Note: "ch" == {"c", "h"}
1187      * A frozen set will not be modified.
1188      * @param s the source string
1189      * @return this object, for chaining
1190      * @stable ICU 2.4
1191      */
1192     UnicodeSet& removeAll(const UnicodeString& s);
1193 
1194     /**
1195      * Makes a set from a multicharacter string. Thus "ch" => {"ch"}
1196      *
1197      * @param s the source string
1198      * @return a newly created set containing the given string.
1199      * The caller owns the return object and is responsible for deleting it.
1200      * @stable ICU 2.4
1201      */
1202     static UnicodeSet* U_EXPORT2 createFrom(const UnicodeString& s);
1203 
1204 
1205     /**
1206      * Makes a set from each of the characters in the string. Thus "ch" => {"c", "h"}
1207      * @param s the source string
1208      * @return a newly created set containing the given characters
1209      * The caller owns the return object and is responsible for deleting it.
1210      * @stable ICU 2.4
1211      */
1212     static UnicodeSet* U_EXPORT2 createFromAll(const UnicodeString& s);
1213 
1214     /**
1215      * Retain only the elements in this set that are contained in the
1216      * specified range.  If <code>start > end</code> then an empty range is
1217      * retained, leaving the set empty.  This is equivalent to
1218      * a boolean logic AND, or a set INTERSECTION.
1219      * A frozen set will not be modified.
1220      *
1221      * @param start first character, inclusive, of range
1222      * @param end last character, inclusive, of range
1223      * @stable ICU 2.0
1224      */
1225     virtual UnicodeSet& retain(UChar32 start, UChar32 end);
1226 
1227 
1228     /**
1229      * Retain the specified character from this set if it is present.
1230      * A frozen set will not be modified.
1231      *
1232      * @param c the character (code point)
1233      * @return this object, for chaining
1234      * @stable ICU 2.0
1235      */
1236     UnicodeSet& retain(UChar32 c);
1237 
1238     /**
1239      * Retains only the specified string from this set if it is present.
1240      * Upon return this set will be empty if it did not contain s, or
1241      * will only contain s if it did contain s.
1242      * A frozen set will not be modified.
1243      *
1244      * @param s the source string
1245      * @return this object, for chaining
1246      * @stable ICU 69
1247      */
1248     UnicodeSet& retain(const UnicodeString &s);
1249 
1250     /**
1251      * Removes the specified range from this set if it is present.
1252      * The set will not contain the specified range once the call
1253      * returns.  If <code>start > end</code> then an empty range is
1254      * removed, leaving the set unchanged.
1255      * A frozen set will not be modified.
1256      *
1257      * @param start first character, inclusive, of range to be removed
1258      * from this set.
1259      * @param end last character, inclusive, of range to be removed
1260      * from this set.
1261      * @stable ICU 2.0
1262      */
1263     virtual UnicodeSet& remove(UChar32 start, UChar32 end);
1264 
1265     /**
1266      * Removes the specified character from this set if it is present.
1267      * The set will not contain the specified range once the call
1268      * returns.
1269      * A frozen set will not be modified.
1270      *
1271      * @param c the character (code point)
1272      * @return this object, for chaining
1273      * @stable ICU 2.0
1274      */
1275     UnicodeSet& remove(UChar32 c);
1276 
1277     /**
1278      * Removes the specified string from this set if it is present.
1279      * The set will not contain the specified character once the call
1280      * returns.
1281      * A frozen set will not be modified.
1282      * @param s the source string
1283      * @return this object, for chaining
1284      * @stable ICU 2.4
1285      */
1286     UnicodeSet& remove(const UnicodeString& s);
1287 
1288     /**
1289      * This is equivalent to
1290      * <code>complement(MIN_VALUE, MAX_VALUE)</code>.
1291      *
1292      * <strong>Note:</strong> This performs a symmetric difference with all code points
1293      * <em>and thus retains all multicharacter strings</em>.
1294      * In order to achieve a “code point complement” (all code points minus this set),
1295      * the easiest is to <code>.complement().removeAllStrings()</code>.
1296      *
1297      * A frozen set will not be modified.
1298      * @stable ICU 2.0
1299      */
1300     virtual UnicodeSet& complement();
1301 
1302     /**
1303      * Complements the specified range in this set.  Any character in
1304      * the range will be removed if it is in this set, or will be
1305      * added if it is not in this set.  If <code>start > end</code>
1306      * then an empty range is complemented, leaving the set unchanged.
1307      * This is equivalent to a boolean logic XOR.
1308      * A frozen set will not be modified.
1309      *
1310      * @param start first character, inclusive, of range
1311      * @param end last character, inclusive, of range
1312      * @stable ICU 2.0
1313      */
1314     virtual UnicodeSet& complement(UChar32 start, UChar32 end);
1315 
1316     /**
1317      * Complements the specified character in this set.  The character
1318      * will be removed if it is in this set, or will be added if it is
1319      * not in this set.
1320      * A frozen set will not be modified.
1321      *
1322      * @param c the character (code point)
1323      * @return this object, for chaining
1324      * @stable ICU 2.0
1325      */
1326     UnicodeSet& complement(UChar32 c);
1327 
1328     /**
1329      * Complement the specified string in this set.
1330      * The string will be removed if it is in this set, or will be added if it is not in this set.
1331      * A frozen set will not be modified.
1332      *
1333      * @param s the string to complement
1334      * @return this object, for chaining
1335      * @stable ICU 2.4
1336      */
1337     UnicodeSet& complement(const UnicodeString& s);
1338 
1339     /**
1340      * Adds all of the elements in the specified set to this set if
1341      * they're not already present.  This operation effectively
1342      * modifies this set so that its value is the <i>union</i> of the two
1343      * sets.  The behavior of this operation is unspecified if the specified
1344      * collection is modified while the operation is in progress.
1345      * A frozen set will not be modified.
1346      *
1347      * @param c set whose elements are to be added to this set.
1348      * @see #add(UChar32, UChar32)
1349      * @stable ICU 2.0
1350      */
1351     virtual UnicodeSet& addAll(const UnicodeSet& c);
1352 
1353     /**
1354      * Retains only the elements in this set that are contained in the
1355      * specified set.  In other words, removes from this set all of
1356      * its elements that are not contained in the specified set.  This
1357      * operation effectively modifies this set so that its value is
1358      * the <i>intersection</i> of the two sets.
1359      * A frozen set will not be modified.
1360      *
1361      * @param c set that defines which elements this set will retain.
1362      * @stable ICU 2.0
1363      */
1364     virtual UnicodeSet& retainAll(const UnicodeSet& c);
1365 
1366     /**
1367      * Removes from this set all of its elements that are contained in the
1368      * specified set.  This operation effectively modifies this
1369      * set so that its value is the <i>asymmetric set difference</i> of
1370      * the two sets.
1371      * A frozen set will not be modified.
1372      *
1373      * @param c set that defines which elements will be removed from
1374      *          this set.
1375      * @stable ICU 2.0
1376      */
1377     virtual UnicodeSet& removeAll(const UnicodeSet& c);
1378 
1379     /**
1380      * Complements in this set all elements contained in the specified
1381      * set.  Any character in the other set will be removed if it is
1382      * in this set, or will be added if it is not in this set.
1383      * A frozen set will not be modified.
1384      *
1385      * @param c set that defines which elements will be xor'ed from
1386      *          this set.
1387      * @stable ICU 2.4
1388      */
1389     virtual UnicodeSet& complementAll(const UnicodeSet& c);
1390 
1391     /**
1392      * Removes all of the elements from this set.  This set will be
1393      * empty after this call returns.
1394      * A frozen set will not be modified.
1395      * @stable ICU 2.0
1396      */
1397     virtual UnicodeSet& clear(void);
1398 
1399     /**
1400      * Close this set over the given attribute.  For the attribute
1401      * USET_CASE_INSENSITIVE, the result is to modify this set so that:
1402      *
1403      * 1. For each character or string 'a' in this set, all strings or
1404      * characters 'b' such that foldCase(a) == foldCase(b) are added
1405      * to this set.
1406      *
1407      * 2. For each string 'e' in the resulting set, if e !=
1408      * foldCase(e), 'e' will be removed.
1409      *
1410      * Example: [aq\\u00DF{Bc}{bC}{Fi}] => [aAqQ\\u00DF\\uFB01{ss}{bc}{fi}]
1411      *
1412      * (Here foldCase(x) refers to the operation u_strFoldCase, and a
1413      * == b denotes that the contents are the same, not pointer
1414      * comparison.)
1415      *
1416      * A frozen set will not be modified.
1417      *
1418      * @param attribute bitmask for attributes to close over.
1419      * Valid options:
1420      * At most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
1421      * These case options are mutually exclusive.
1422      * Unrelated options bits are ignored.
1423      * @return a reference to this set.
1424      * @stable ICU 4.2
1425      */
1426     UnicodeSet& closeOver(int32_t attribute);
1427 
1428     /**
1429      * Remove all strings from this set.
1430      *
1431      * @return a reference to this set.
1432      * @stable ICU 4.2
1433      */
1434     virtual UnicodeSet &removeAllStrings();
1435 
1436     /**
1437      * Iteration method that returns the number of ranges contained in
1438      * this set.
1439      * @see #getRangeStart
1440      * @see #getRangeEnd
1441      * @stable ICU 2.4
1442      */
1443     virtual int32_t getRangeCount(void) const;
1444 
1445     /**
1446      * Iteration method that returns the first character in the
1447      * specified range of this set.
1448      * @see #getRangeCount
1449      * @see #getRangeEnd
1450      * @stable ICU 2.4
1451      */
1452     virtual UChar32 getRangeStart(int32_t index) const;
1453 
1454     /**
1455      * Iteration method that returns the last character in the
1456      * specified range of this set.
1457      * @see #getRangeStart
1458      * @see #getRangeEnd
1459      * @stable ICU 2.4
1460      */
1461     virtual UChar32 getRangeEnd(int32_t index) const;
1462 
1463     /**
1464      * Serializes this set into an array of 16-bit integers.  Serialization
1465      * (currently) only records the characters in the set; multicharacter
1466      * strings are ignored.
1467      *
1468      * The array has following format (each line is one 16-bit
1469      * integer):
1470      *
1471      *  length     = (n+2*m) | (m!=0?0x8000:0)
1472      *  bmpLength  = n; present if m!=0
1473      *  bmp[0]
1474      *  bmp[1]
1475      *  ...
1476      *  bmp[n-1]
1477      *  supp-high[0]
1478      *  supp-low[0]
1479      *  supp-high[1]
1480      *  supp-low[1]
1481      *  ...
1482      *  supp-high[m-1]
1483      *  supp-low[m-1]
1484      *
1485      * The array starts with a header.  After the header are n bmp
1486      * code points, then m supplementary code points.  Either n or m
1487      * or both may be zero.  n+2*m is always <= 0x7FFF.
1488      *
1489      * If there are no supplementary characters (if m==0) then the
1490      * header is one 16-bit integer, 'length', with value n.
1491      *
1492      * If there are supplementary characters (if m!=0) then the header
1493      * is two 16-bit integers.  The first, 'length', has value
1494      * (n+2*m)|0x8000.  The second, 'bmpLength', has value n.
1495      *
1496      * After the header the code points are stored in ascending order.
1497      * Supplementary code points are stored as most significant 16
1498      * bits followed by least significant 16 bits.
1499      *
1500      * @param dest pointer to buffer of destCapacity 16-bit integers.
1501      * May be nullptr only if destCapacity is zero.
1502      * @param destCapacity size of dest, or zero.  Must not be negative.
1503      * @param ec error code.  Will be set to U_INDEX_OUTOFBOUNDS_ERROR
1504      * if n+2*m > 0x7FFF.  Will be set to U_BUFFER_OVERFLOW_ERROR if
1505      * n+2*m+(m!=0?2:1) > destCapacity.
1506      * @return the total length of the serialized format, including
1507      * the header, that is, n+2*m+(m!=0?2:1), or 0 on error other
1508      * than U_BUFFER_OVERFLOW_ERROR.
1509      * @stable ICU 2.4
1510      */
1511     int32_t serialize(uint16_t *dest, int32_t destCapacity, UErrorCode& ec) const;
1512 
1513     /**
1514      * Reallocate this objects internal structures to take up the least
1515      * possible space, without changing this object's value.
1516      * A frozen set will not be modified.
1517      * @stable ICU 2.4
1518      */
1519     virtual UnicodeSet& compact();
1520 
1521     /**
1522      * Return the class ID for this class.  This is useful only for
1523      * comparing to a return value from getDynamicClassID().  For example:
1524      * <pre>
1525      * .      Base* polymorphic_pointer = createPolymorphicObject();
1526      * .      if (polymorphic_pointer->getDynamicClassID() ==
1527      * .          Derived::getStaticClassID()) ...
1528      * </pre>
1529      * @return          The class ID for all objects of this class.
1530      * @stable ICU 2.0
1531      */
1532     static UClassID U_EXPORT2 getStaticClassID(void);
1533 
1534     /**
1535      * Implement UnicodeFunctor API.
1536      *
1537      * @return The class ID for this object. All objects of a given
1538      * class have the same class ID.  Objects of other classes have
1539      * different class IDs.
1540      * @stable ICU 2.4
1541      */
1542     virtual UClassID getDynamicClassID(void) const override;
1543 
1544 private:
1545 
1546     // Private API for the USet API
1547 
1548     friend class USetAccess;
1549 
1550     const UnicodeString* getString(int32_t index) const;
1551 
1552     //----------------------------------------------------------------
1553     // RuleBasedTransliterator support
1554     //----------------------------------------------------------------
1555 
1556 private:
1557 
1558     /**
1559      * Returns <tt>true</tt> if this set contains any character whose low byte
1560      * is the given value.  This is used by <tt>RuleBasedTransliterator</tt> for
1561      * indexing.
1562      */
1563     virtual UBool matchesIndexValue(uint8_t v) const override;
1564 
1565 private:
1566     friend class RBBIRuleScanner;
1567 
1568     //----------------------------------------------------------------
1569     // Implementation: Clone as thawed (see ICU4J Freezable)
1570     //----------------------------------------------------------------
1571 
1572     UnicodeSet(const UnicodeSet& o, UBool /* asThawed */);
1573     UnicodeSet& copyFrom(const UnicodeSet& o, UBool asThawed);
1574 
1575     //----------------------------------------------------------------
1576     // Implementation: Pattern parsing
1577     //----------------------------------------------------------------
1578 
1579     void applyPatternIgnoreSpace(const UnicodeString& pattern,
1580                                  ParsePosition& pos,
1581                                  const SymbolTable* symbols,
1582                                  UErrorCode& status);
1583 
1584     void applyPattern(RuleCharacterIterator& chars,
1585                       const SymbolTable* symbols,
1586                       UnicodeString& rebuiltPat,
1587                       uint32_t options,
1588                       UnicodeSet& (UnicodeSet::*caseClosure)(int32_t attribute),
1589                       int32_t depth,
1590                       UErrorCode& ec);
1591 
1592     void closeOverCaseInsensitive(bool simple);
1593     void closeOverAddCaseMappings();
1594 
1595     //----------------------------------------------------------------
1596     // Implementation: Utility methods
1597     //----------------------------------------------------------------
1598 
1599     static int32_t nextCapacity(int32_t minCapacity);
1600 
1601     bool ensureCapacity(int32_t newLen);
1602 
1603     bool ensureBufferCapacity(int32_t newLen);
1604 
1605     void swapBuffers(void);
1606 
1607     UBool allocateStrings(UErrorCode &status);
1608     int32_t stringsSize() const;
1609     UBool stringsContains(const UnicodeString &s) const;
1610 
1611     UnicodeString& _toPattern(UnicodeString& result,
1612                               UBool escapeUnprintable) const;
1613 
1614     UnicodeString& _generatePattern(UnicodeString& result,
1615                                     UBool escapeUnprintable) const;
1616 
1617     static void _appendToPat(UnicodeString& buf, const UnicodeString& s, UBool escapeUnprintable);
1618 
1619     static void _appendToPat(UnicodeString& buf, UChar32 c, UBool escapeUnprintable);
1620 
1621     static void _appendToPat(UnicodeString &result, UChar32 start, UChar32 end,
1622                              UBool escapeUnprintable);
1623 
1624     //----------------------------------------------------------------
1625     // Implementation: Fundamental operators
1626     //----------------------------------------------------------------
1627 
1628     void exclusiveOr(const UChar32* other, int32_t otherLen, int8_t polarity);
1629 
1630     void add(const UChar32* other, int32_t otherLen, int8_t polarity);
1631 
1632     void retain(const UChar32* other, int32_t otherLen, int8_t polarity);
1633 
1634     /**
1635      * Return true if the given position, in the given pattern, appears
1636      * to be the start of a property set pattern [:foo:], \\p{foo}, or
1637      * \\P{foo}, or \\N{name}.
1638      */
1639     static UBool resemblesPropertyPattern(const UnicodeString& pattern,
1640                                           int32_t pos);
1641 
1642     static UBool resemblesPropertyPattern(RuleCharacterIterator& chars,
1643                                           int32_t iterOpts);
1644 
1645     /**
1646      * Parse the given property pattern at the given parse position
1647      * and set this UnicodeSet to the result.
1648      *
1649      * The original design document is out of date, but still useful.
1650      * Ignore the property and value names:
1651      * https://htmlpreview.github.io/?https://github.com/unicode-org/icu-docs/blob/main/design/unicodeset_properties.html
1652      *
1653      * Recognized syntax:
1654      *
1655      * [:foo:] [:^foo:] - white space not allowed within "[:" or ":]"
1656      * \\p{foo} \\P{foo}  - white space not allowed within "\\p" or "\\P"
1657      * \\N{name}         - white space not allowed within "\\N"
1658      *
1659      * Other than the above restrictions, Unicode Pattern_White_Space characters are ignored.
1660      * Case is ignored except in "\\p" and "\\P" and "\\N".  In 'name' leading
1661      * and trailing space is deleted, and internal runs of whitespace
1662      * are collapsed to a single space.
1663      *
1664      * We support binary properties, enumerated properties, and the
1665      * following non-enumerated properties:
1666      *
1667      *  Numeric_Value
1668      *  Name
1669      *  Unicode_1_Name
1670      *
1671      * @param pattern the pattern string
1672      * @param ppos on entry, the position at which to begin parsing.
1673      * This should be one of the locations marked '^':
1674      *
1675      *   [:blah:]     \\p{blah}     \\P{blah}     \\N{name}
1676      *   ^       %    ^       %    ^       %    ^       %
1677      *
1678      * On return, the position after the last character parsed, that is,
1679      * the locations marked '%'.  If the parse fails, ppos is returned
1680      * unchanged.
1681      * @param ec status
1682      * @return a reference to this.
1683      */
1684     UnicodeSet& applyPropertyPattern(const UnicodeString& pattern,
1685                                      ParsePosition& ppos,
1686                                      UErrorCode &ec);
1687 
1688     void applyPropertyPattern(RuleCharacterIterator& chars,
1689                               UnicodeString& rebuiltPat,
1690                               UErrorCode& ec);
1691 
1692     /**
1693      * A filter that returns true if the given code point should be
1694      * included in the UnicodeSet being constructed.
1695      */
1696     typedef UBool (*Filter)(UChar32 codePoint, void* context);
1697 
1698     /**
1699      * Given a filter, set this UnicodeSet to the code points
1700      * contained by that filter.  The filter MUST be
1701      * property-conformant.  That is, if it returns value v for one
1702      * code point, then it must return v for all affiliated code
1703      * points, as defined by the inclusions list.  See
1704      * getInclusions().
1705      * src is a UPropertySource value.
1706      */
1707     void applyFilter(Filter filter,
1708                      void* context,
1709                      const UnicodeSet* inclusions,
1710                      UErrorCode &status);
1711 
1712     /**
1713      * Set the new pattern to cache.
1714      */
setPattern(const UnicodeString & newPat)1715     void setPattern(const UnicodeString& newPat) {
1716         setPattern(newPat.getBuffer(), newPat.length());
1717     }
1718     void setPattern(const char16_t *newPat, int32_t newPatLen);
1719     /**
1720      * Release existing cached pattern.
1721      */
1722     void releasePattern();
1723 
1724     friend class UnicodeSetIterator;
1725 };
1726 
1727 
1728 
1729 inline bool UnicodeSet::operator!=(const UnicodeSet& o) const {
1730     return !operator==(o);
1731 }
1732 
isFrozen()1733 inline UBool UnicodeSet::isFrozen() const {
1734     return (UBool)(bmpSet!=nullptr || stringSpan!=nullptr);
1735 }
1736 
containsSome(UChar32 start,UChar32 end)1737 inline UBool UnicodeSet::containsSome(UChar32 start, UChar32 end) const {
1738     return !containsNone(start, end);
1739 }
1740 
containsSome(const UnicodeSet & s)1741 inline UBool UnicodeSet::containsSome(const UnicodeSet& s) const {
1742     return !containsNone(s);
1743 }
1744 
containsSome(const UnicodeString & s)1745 inline UBool UnicodeSet::containsSome(const UnicodeString& s) const {
1746     return !containsNone(s);
1747 }
1748 
isBogus()1749 inline UBool UnicodeSet::isBogus() const {
1750     return (UBool)(fFlags & kIsBogus);
1751 }
1752 
fromUSet(USet * uset)1753 inline UnicodeSet *UnicodeSet::fromUSet(USet *uset) {
1754     return reinterpret_cast<UnicodeSet *>(uset);
1755 }
1756 
fromUSet(const USet * uset)1757 inline const UnicodeSet *UnicodeSet::fromUSet(const USet *uset) {
1758     return reinterpret_cast<const UnicodeSet *>(uset);
1759 }
1760 
toUSet()1761 inline USet *UnicodeSet::toUSet() {
1762     return reinterpret_cast<USet *>(this);
1763 }
1764 
toUSet()1765 inline const USet *UnicodeSet::toUSet() const {
1766     return reinterpret_cast<const USet *>(this);
1767 }
1768 
span(const UnicodeString & s,int32_t start,USetSpanCondition spanCondition)1769 inline int32_t UnicodeSet::span(const UnicodeString &s, int32_t start, USetSpanCondition spanCondition) const {
1770     int32_t sLength=s.length();
1771     if(start<0) {
1772         start=0;
1773     } else if(start>sLength) {
1774         start=sLength;
1775     }
1776     return start+span(s.getBuffer()+start, sLength-start, spanCondition);
1777 }
1778 
spanBack(const UnicodeString & s,int32_t limit,USetSpanCondition spanCondition)1779 inline int32_t UnicodeSet::spanBack(const UnicodeString &s, int32_t limit, USetSpanCondition spanCondition) const {
1780     int32_t sLength=s.length();
1781     if(limit<0) {
1782         limit=0;
1783     } else if(limit>sLength) {
1784         limit=sLength;
1785     }
1786     return spanBack(s.getBuffer(), limit, spanCondition);
1787 }
1788 
1789 U_NAMESPACE_END
1790 
1791 #endif /* U_SHOW_CPLUSPLUS_API */
1792 
1793 #endif
1794