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uniset.h (71860B)


      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() 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    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    int32_t hashCode() 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    int32_t size() 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    UBool isEmpty() 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    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    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    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     * Returns a C++ "range" for iterating over the code points of this set.
   1107     *
   1108     * \code
   1109     * UnicodeSet set(u"[abcçカ🚴]", errorCode);
   1110     * for (UChar32 c : set.codePoints()) {
   1111     *     printf("set.codePoint U+%04lx\n", (long)c);
   1112     * }
   1113     * \endcode
   1114     *
   1115     * @return a "range" object for iterating over the code points of this set.
   1116     * @stable ICU 76
   1117     * @see ranges
   1118     * @see strings
   1119     * @see begin
   1120     * @see end
   1121     */
   1122    inline U_HEADER_NESTED_NAMESPACE::USetCodePoints codePoints() const {
   1123        return U_HEADER_NESTED_NAMESPACE::USetCodePoints(toUSet());
   1124    }
   1125 
   1126    /**
   1127     * Returns a C++ "range" for iterating over the code point ranges of this set.
   1128     *
   1129     * \code
   1130     * UnicodeSet set(u"[abcçカ🚴]", errorCode);
   1131     * for (auto [start, end] : set.ranges()) {
   1132     *     printf("set.range U+%04lx..U+%04lx\n", (long)start, (long)end);
   1133     * }
   1134     * for (auto range : set.ranges()) {
   1135     *     for (UChar32 c : range) {
   1136     *         printf("set.range.c U+%04lx\n", (long)c);
   1137     *     }
   1138     * }
   1139     * \endcode
   1140     *
   1141     * @return a "range" object for iterating over the code point ranges of this set.
   1142     * @stable ICU 76
   1143     * @see codePoints
   1144     * @see strings
   1145     * @see begin
   1146     * @see end
   1147     */
   1148    inline U_HEADER_NESTED_NAMESPACE::USetRanges ranges() const {
   1149        return U_HEADER_NESTED_NAMESPACE::USetRanges(toUSet());
   1150    }
   1151 
   1152    /**
   1153     * Returns a C++ "range" for iterating over the empty and multi-character strings of this set.
   1154     * Returns each string as a std::u16string_view without copying its contents.
   1155     *
   1156     * \code
   1157     * UnicodeSet set(u"[abcçカ🚴{}{abc}{de}]", errorCode);
   1158     * for (auto s : set.strings()) {
   1159     *     UnicodeString us(s);
   1160     *     std::string u8;
   1161     *     printf("set.string length %ld \"%s\"\n", (long)s.length(), us.toUTF8String(u8).c_str());
   1162     * }
   1163     * \endcode
   1164     *
   1165     * @return a "range" object for iterating over the strings of this set.
   1166     * @stable ICU 76
   1167     * @see codePoints
   1168     * @see ranges
   1169     * @see begin
   1170     * @see end
   1171     */
   1172    inline U_HEADER_NESTED_NAMESPACE::USetStrings strings() const {
   1173        return U_HEADER_NESTED_NAMESPACE::USetStrings(toUSet());
   1174    }
   1175 
   1176 #ifndef U_HIDE_DRAFT_API
   1177    /**
   1178     * Returns a C++ iterator for iterating over all of the elements of this set.
   1179     * Convenient all-in one iteration, but creates a std::u16string for each
   1180     * code point or string.
   1181     * (Similar to how Java UnicodeSet *is an* Iterable&lt;String&gt;.)
   1182     *
   1183     * Code points are returned first, then empty and multi-character strings.
   1184     *
   1185     * \code
   1186     * UnicodeSet set(u"[abcçカ🚴{}{abc}{de}]", errorCode);
   1187     * for (auto el : set) {
   1188     *     UnicodeString us(el);
   1189     *     std::string u8;
   1190     *     printf("set.element length %ld \"%s\"\n", (long)us.length(), us.toUTF8String(u8).c_str());
   1191     * }
   1192     * \endcode
   1193     *
   1194     * @return an all-elements iterator.
   1195     * @draft ICU 77
   1196     * @see end
   1197     * @see codePoints
   1198     * @see ranges
   1199     * @see strings
   1200     */
   1201    inline U_HEADER_NESTED_NAMESPACE::USetElementIterator begin() const {
   1202        return U_HEADER_NESTED_NAMESPACE::USetElements(toUSet()).begin();
   1203    }
   1204 
   1205    /**
   1206     * @return an exclusive-end sentinel for iterating over all of the elements of this set.
   1207     * @draft ICU 77
   1208     * @see begin
   1209     * @see codePoints
   1210     * @see ranges
   1211     * @see strings
   1212     */
   1213    inline U_HEADER_NESTED_NAMESPACE::USetElementIterator end() const {
   1214        return U_HEADER_NESTED_NAMESPACE::USetElements(toUSet()).end();
   1215    }
   1216 #endif  // U_HIDE_DRAFT_API
   1217 
   1218    /**
   1219     * Adds the specified range to this set if it is not already
   1220     * present.  If this set already contains the specified range,
   1221     * the call leaves this set unchanged.  If <code>start > end</code>
   1222     * then an empty range is added, leaving the set unchanged.
   1223     * This is equivalent to a boolean logic OR, or a set UNION.
   1224     * A frozen set will not be modified.
   1225     *
   1226     * @param start first character, inclusive, of range to be added
   1227     * to this set.
   1228     * @param end last character, inclusive, of range to be added
   1229     * to this set.
   1230     * @stable ICU 2.0
   1231     */
   1232    UnicodeSet& add(UChar32 start, UChar32 end);
   1233 
   1234    /**
   1235     * Adds the specified character to this set if it is not already
   1236     * present.  If this set already contains the specified character,
   1237     * the call leaves this set unchanged.
   1238     * A frozen set will not be modified.
   1239     *
   1240     * @param c the character (code point)
   1241     * @return this object, for chaining
   1242     * @stable ICU 2.0
   1243     */
   1244    UnicodeSet& add(UChar32 c);
   1245 
   1246    /**
   1247     * Adds the specified multicharacter to this set if it is not already
   1248     * present.  If this set already contains the multicharacter,
   1249     * the call leaves this set unchanged.
   1250     * Thus "ch" => {"ch"}
   1251     * A frozen set will not be modified.
   1252     *
   1253     * @param s the source string
   1254     * @return this object, for chaining
   1255     * @stable ICU 2.4
   1256     */
   1257    UnicodeSet& add(const UnicodeString& s);
   1258 
   1259 private:
   1260    /**
   1261     * @return a code point IF the string consists of a single one.
   1262     * otherwise returns -1.
   1263     * @param s string to test
   1264     */
   1265    static int32_t getSingleCP(const UnicodeString& s);
   1266 
   1267    void _add(const UnicodeString& s);
   1268 
   1269 public:
   1270    /**
   1271     * Adds each of the characters in this string to the set. Note: "ch" => {"c", "h"}
   1272     * If this set already contains any particular character, it has no effect on that character.
   1273     * A frozen set will not be modified.
   1274     * @param s the source string
   1275     * @return this object, for chaining
   1276     * @stable ICU 2.4
   1277     */
   1278    UnicodeSet& addAll(const UnicodeString& s);
   1279 
   1280    /**
   1281     * Retains EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1282     * A frozen set will not be modified.
   1283     * @param s the source string
   1284     * @return this object, for chaining
   1285     * @stable ICU 2.4
   1286     */
   1287    UnicodeSet& retainAll(const UnicodeString& s);
   1288 
   1289    /**
   1290     * Complement EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1291     * A frozen set will not be modified.
   1292     * @param s the source string
   1293     * @return this object, for chaining
   1294     * @stable ICU 2.4
   1295     */
   1296    UnicodeSet& complementAll(const UnicodeString& s);
   1297 
   1298    /**
   1299     * Remove EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1300     * A frozen set will not be modified.
   1301     * @param s the source string
   1302     * @return this object, for chaining
   1303     * @stable ICU 2.4
   1304     */
   1305    UnicodeSet& removeAll(const UnicodeString& s);
   1306 
   1307    /**
   1308     * Makes a set from a multicharacter string. Thus "ch" => {"ch"}
   1309     *
   1310     * @param s the source string
   1311     * @return a newly created set containing the given string.
   1312     * The caller owns the return object and is responsible for deleting it.
   1313     * @stable ICU 2.4
   1314     */
   1315    static UnicodeSet* U_EXPORT2 createFrom(const UnicodeString& s);
   1316 
   1317 
   1318    /**
   1319     * Makes a set from each of the characters in the string. Thus "ch" => {"c", "h"}
   1320     * @param s the source string
   1321     * @return a newly created set containing the given characters
   1322     * The caller owns the return object and is responsible for deleting it.
   1323     * @stable ICU 2.4
   1324     */
   1325    static UnicodeSet* U_EXPORT2 createFromAll(const UnicodeString& s);
   1326 
   1327    /**
   1328     * Retain only the elements in this set that are contained in the
   1329     * specified range.  If <code>start > end</code> then an empty range is
   1330     * retained, leaving the set empty.  This is equivalent to
   1331     * a boolean logic AND, or a set INTERSECTION.
   1332     * A frozen set will not be modified.
   1333     *
   1334     * @param start first character, inclusive, of range
   1335     * @param end last character, inclusive, of range
   1336     * @stable ICU 2.0
   1337     */
   1338    UnicodeSet& retain(UChar32 start, UChar32 end);
   1339 
   1340 
   1341    /**
   1342     * Retain the specified character from this set if it is present.
   1343     * A frozen set will not be modified.
   1344     *
   1345     * @param c the character (code point)
   1346     * @return this object, for chaining
   1347     * @stable ICU 2.0
   1348     */
   1349    UnicodeSet& retain(UChar32 c);
   1350 
   1351    /**
   1352     * Retains only the specified string from this set if it is present.
   1353     * Upon return this set will be empty if it did not contain s, or
   1354     * will only contain s if it did contain s.
   1355     * A frozen set will not be modified.
   1356     *
   1357     * @param s the source string
   1358     * @return this object, for chaining
   1359     * @stable ICU 69
   1360     */
   1361    UnicodeSet& retain(const UnicodeString &s);
   1362 
   1363    /**
   1364     * Removes the specified range from this set if it is present.
   1365     * The set will not contain the specified range once the call
   1366     * returns.  If <code>start > end</code> then an empty range is
   1367     * removed, leaving the set unchanged.
   1368     * A frozen set will not be modified.
   1369     *
   1370     * @param start first character, inclusive, of range to be removed
   1371     * from this set.
   1372     * @param end last character, inclusive, of range to be removed
   1373     * from this set.
   1374     * @stable ICU 2.0
   1375     */
   1376    UnicodeSet& remove(UChar32 start, UChar32 end);
   1377 
   1378    /**
   1379     * Removes the specified character from this set if it is present.
   1380     * The set will not contain the specified range once the call
   1381     * returns.
   1382     * A frozen set will not be modified.
   1383     *
   1384     * @param c the character (code point)
   1385     * @return this object, for chaining
   1386     * @stable ICU 2.0
   1387     */
   1388    UnicodeSet& remove(UChar32 c);
   1389 
   1390    /**
   1391     * Removes the specified string from this set if it is present.
   1392     * The set will not contain the specified character once the call
   1393     * returns.
   1394     * A frozen set will not be modified.
   1395     * @param s the source string
   1396     * @return this object, for chaining
   1397     * @stable ICU 2.4
   1398     */
   1399    UnicodeSet& remove(const UnicodeString& s);
   1400 
   1401    /**
   1402     * This is equivalent to
   1403     * <code>complement(MIN_VALUE, MAX_VALUE)</code>.
   1404     *
   1405     * <strong>Note:</strong> This performs a symmetric difference with all code points
   1406     * <em>and thus retains all multicharacter strings</em>.
   1407     * In order to achieve a “code point complement” (all code points minus this set),
   1408     * the easiest is to <code>.complement().removeAllStrings()</code>.
   1409     *
   1410     * A frozen set will not be modified.
   1411     * @stable ICU 2.0
   1412     */
   1413    UnicodeSet& complement();
   1414 
   1415    /**
   1416     * Complements the specified range in this set.  Any character in
   1417     * the range will be removed if it is in this set, or will be
   1418     * added if it is not in this set.  If <code>start > end</code>
   1419     * then an empty range is complemented, leaving the set unchanged.
   1420     * This is equivalent to a boolean logic XOR.
   1421     * A frozen set will not be modified.
   1422     *
   1423     * @param start first character, inclusive, of range
   1424     * @param end last character, inclusive, of range
   1425     * @stable ICU 2.0
   1426     */
   1427    UnicodeSet& complement(UChar32 start, UChar32 end);
   1428 
   1429    /**
   1430     * Complements the specified character in this set.  The character
   1431     * will be removed if it is in this set, or will be added if it is
   1432     * not in this set.
   1433     * A frozen set will not be modified.
   1434     *
   1435     * @param c the character (code point)
   1436     * @return this object, for chaining
   1437     * @stable ICU 2.0
   1438     */
   1439    UnicodeSet& complement(UChar32 c);
   1440 
   1441    /**
   1442     * Complement the specified string in this set.
   1443     * The string will be removed if it is in this set, or will be added if it is not in this set.
   1444     * A frozen set will not be modified.
   1445     *
   1446     * @param s the string to complement
   1447     * @return this object, for chaining
   1448     * @stable ICU 2.4
   1449     */
   1450    UnicodeSet& complement(const UnicodeString& s);
   1451 
   1452    /**
   1453     * Adds all of the elements in the specified set to this set if
   1454     * they're not already present.  This operation effectively
   1455     * modifies this set so that its value is the <i>union</i> of the two
   1456     * sets.  The behavior of this operation is unspecified if the specified
   1457     * collection is modified while the operation is in progress.
   1458     * A frozen set will not be modified.
   1459     *
   1460     * @param c set whose elements are to be added to this set.
   1461     * @see #add(UChar32, UChar32)
   1462     * @stable ICU 2.0
   1463     */
   1464    UnicodeSet& addAll(const UnicodeSet& c);
   1465 
   1466    /**
   1467     * Retains only the elements in this set that are contained in the
   1468     * specified set.  In other words, removes from this set all of
   1469     * its elements that are not contained in the specified set.  This
   1470     * operation effectively modifies this set so that its value is
   1471     * the <i>intersection</i> of the two sets.
   1472     * A frozen set will not be modified.
   1473     *
   1474     * @param c set that defines which elements this set will retain.
   1475     * @stable ICU 2.0
   1476     */
   1477    UnicodeSet& retainAll(const UnicodeSet& c);
   1478 
   1479    /**
   1480     * Removes from this set all of its elements that are contained in the
   1481     * specified set.  This operation effectively modifies this
   1482     * set so that its value is the <i>asymmetric set difference</i> of
   1483     * the two sets.
   1484     * A frozen set will not be modified.
   1485     *
   1486     * @param c set that defines which elements will be removed from
   1487     *          this set.
   1488     * @stable ICU 2.0
   1489     */
   1490    UnicodeSet& removeAll(const UnicodeSet& c);
   1491 
   1492    /**
   1493     * Complements in this set all elements contained in the specified
   1494     * set.  Any character in the other set will be removed if it is
   1495     * in this set, or will be added if it is not in this set.
   1496     * A frozen set will not be modified.
   1497     *
   1498     * @param c set that defines which elements will be xor'ed from
   1499     *          this set.
   1500     * @stable ICU 2.4
   1501     */
   1502    UnicodeSet& complementAll(const UnicodeSet& c);
   1503 
   1504    /**
   1505     * Removes all of the elements from this set.  This set will be
   1506     * empty after this call returns.
   1507     * A frozen set will not be modified.
   1508     * @stable ICU 2.0
   1509     */
   1510    UnicodeSet& clear();
   1511 
   1512    /**
   1513     * Close this set over the given attribute.  For the attribute
   1514     * USET_CASE_INSENSITIVE, the result is to modify this set so that:
   1515     *
   1516     * 1. For each character or string 'a' in this set, all strings or
   1517     * characters 'b' such that foldCase(a) == foldCase(b) are added
   1518     * to this set.
   1519     *
   1520     * 2. For each string 'e' in the resulting set, if e !=
   1521     * foldCase(e), 'e' will be removed.
   1522     *
   1523     * Example: [aq\\u00DF{Bc}{bC}{Fi}] => [aAqQ\\u00DF\\uFB01{ss}{bc}{fi}]
   1524     *
   1525     * (Here foldCase(x) refers to the operation u_strFoldCase, and a
   1526     * == b denotes that the contents are the same, not pointer
   1527     * comparison.)
   1528     *
   1529     * A frozen set will not be modified.
   1530     *
   1531     * @param attribute bitmask for attributes to close over.
   1532     * Valid options:
   1533     * At most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
   1534     * These case options are mutually exclusive.
   1535     * Unrelated options bits are ignored.
   1536     * @return a reference to this set.
   1537     * @stable ICU 4.2
   1538     */
   1539    UnicodeSet& closeOver(int32_t attribute);
   1540 
   1541    /**
   1542     * Remove all strings from this set.
   1543     *
   1544     * @return a reference to this set.
   1545     * @stable ICU 4.2
   1546     */
   1547    UnicodeSet &removeAllStrings();
   1548 
   1549    /**
   1550     * Iteration method that returns the number of ranges contained in
   1551     * this set.
   1552     * @see #getRangeStart
   1553     * @see #getRangeEnd
   1554     * @stable ICU 2.4
   1555     */
   1556    int32_t getRangeCount() const;
   1557 
   1558    /**
   1559     * Iteration method that returns the first character in the
   1560     * specified range of this set.
   1561     * @see #getRangeCount
   1562     * @see #getRangeEnd
   1563     * @stable ICU 2.4
   1564     */
   1565    UChar32 getRangeStart(int32_t index) const;
   1566 
   1567    /**
   1568     * Iteration method that returns the last character in the
   1569     * specified range of this set.
   1570     * @see #getRangeStart
   1571     * @see #getRangeEnd
   1572     * @stable ICU 2.4
   1573     */
   1574    UChar32 getRangeEnd(int32_t index) const;
   1575 
   1576    /**
   1577     * Serializes this set into an array of 16-bit integers.  Serialization
   1578     * (currently) only records the characters in the set; multicharacter
   1579     * strings are ignored.
   1580     *
   1581     * The array has following format (each line is one 16-bit
   1582     * integer):
   1583     *
   1584     *  length     = (n+2*m) | (m!=0?0x8000:0)
   1585     *  bmpLength  = n; present if m!=0
   1586     *  bmp[0]
   1587     *  bmp[1]
   1588     *  ...
   1589     *  bmp[n-1]
   1590     *  supp-high[0]
   1591     *  supp-low[0]
   1592     *  supp-high[1]
   1593     *  supp-low[1]
   1594     *  ...
   1595     *  supp-high[m-1]
   1596     *  supp-low[m-1]
   1597     *
   1598     * The array starts with a header.  After the header are n bmp
   1599     * code points, then m supplementary code points.  Either n or m
   1600     * or both may be zero.  n+2*m is always <= 0x7FFF.
   1601     *
   1602     * If there are no supplementary characters (if m==0) then the
   1603     * header is one 16-bit integer, 'length', with value n.
   1604     *
   1605     * If there are supplementary characters (if m!=0) then the header
   1606     * is two 16-bit integers.  The first, 'length', has value
   1607     * (n+2*m)|0x8000.  The second, 'bmpLength', has value n.
   1608     *
   1609     * After the header the code points are stored in ascending order.
   1610     * Supplementary code points are stored as most significant 16
   1611     * bits followed by least significant 16 bits.
   1612     *
   1613     * @param dest pointer to buffer of destCapacity 16-bit integers.
   1614     * May be nullptr only if destCapacity is zero.
   1615     * @param destCapacity size of dest, or zero.  Must not be negative.
   1616     * @param ec error code.  Will be set to U_INDEX_OUTOFBOUNDS_ERROR
   1617     * if n+2*m > 0x7FFF.  Will be set to U_BUFFER_OVERFLOW_ERROR if
   1618     * n+2*m+(m!=0?2:1) > destCapacity.
   1619     * @return the total length of the serialized format, including
   1620     * the header, that is, n+2*m+(m!=0?2:1), or 0 on error other
   1621     * than U_BUFFER_OVERFLOW_ERROR.
   1622     * @stable ICU 2.4
   1623     */
   1624    int32_t serialize(uint16_t *dest, int32_t destCapacity, UErrorCode& ec) const;
   1625 
   1626    /**
   1627     * Reallocate this objects internal structures to take up the least
   1628     * possible space, without changing this object's value.
   1629     * A frozen set will not be modified.
   1630     * @stable ICU 2.4
   1631     */
   1632    UnicodeSet& compact();
   1633 
   1634    /**
   1635     * Return the class ID for this class.  This is useful only for
   1636     * comparing to a return value from getDynamicClassID().  For example:
   1637     * <pre>
   1638     * .      Base* polymorphic_pointer = createPolymorphicObject();
   1639     * .      if (polymorphic_pointer->getDynamicClassID() ==
   1640     * .          Derived::getStaticClassID()) ...
   1641     * </pre>
   1642     * @return          The class ID for all objects of this class.
   1643     * @stable ICU 2.0
   1644     */
   1645    static UClassID U_EXPORT2 getStaticClassID();
   1646 
   1647    /**
   1648     * Implement UnicodeFunctor API.
   1649     *
   1650     * @return The class ID for this object. All objects of a given
   1651     * class have the same class ID.  Objects of other classes have
   1652     * different class IDs.
   1653     * @stable ICU 2.4
   1654     */
   1655    virtual UClassID getDynamicClassID() const override;
   1656 
   1657  private:
   1658 
   1659    // Private API for the USet API
   1660 
   1661    friend class USetAccess;
   1662 
   1663    const UnicodeString* getString(int32_t index) const;
   1664 
   1665    //----------------------------------------------------------------
   1666    // RuleBasedTransliterator support
   1667    //----------------------------------------------------------------
   1668 
   1669 private:
   1670 
   1671    /**
   1672     * Returns <tt>true</tt> if this set contains any character whose low byte
   1673     * is the given value.  This is used by <tt>RuleBasedTransliterator</tt> for
   1674     * indexing.
   1675     */
   1676    virtual UBool matchesIndexValue(uint8_t v) const override;
   1677 
   1678 private:
   1679    friend class RBBIRuleScanner;
   1680 
   1681    //----------------------------------------------------------------
   1682    // Implementation: Clone as thawed (see ICU4J Freezable)
   1683    //----------------------------------------------------------------
   1684 
   1685    UnicodeSet(const UnicodeSet& o, UBool /* asThawed */);
   1686    UnicodeSet& copyFrom(const UnicodeSet& o, UBool asThawed);
   1687 
   1688    //----------------------------------------------------------------
   1689    // Implementation: Pattern parsing
   1690    //----------------------------------------------------------------
   1691 
   1692    void applyPatternIgnoreSpace(const UnicodeString& pattern,
   1693                                 ParsePosition& pos,
   1694                                 const SymbolTable* symbols,
   1695                                 UErrorCode& status);
   1696 
   1697    void applyPattern(RuleCharacterIterator& chars,
   1698                      const SymbolTable* symbols,
   1699                      UnicodeString& rebuiltPat,
   1700                      uint32_t options,
   1701                      UnicodeSet& (UnicodeSet::*caseClosure)(int32_t attribute),
   1702                      int32_t depth,
   1703                      UErrorCode& ec);
   1704 
   1705    void closeOverCaseInsensitive(bool simple);
   1706    void closeOverAddCaseMappings();
   1707 
   1708    //----------------------------------------------------------------
   1709    // Implementation: Utility methods
   1710    //----------------------------------------------------------------
   1711 
   1712    static int32_t nextCapacity(int32_t minCapacity);
   1713 
   1714    bool ensureCapacity(int32_t newLen);
   1715 
   1716    bool ensureBufferCapacity(int32_t newLen);
   1717 
   1718    void swapBuffers();
   1719 
   1720    UBool allocateStrings(UErrorCode &status);
   1721    int32_t stringsSize() const;
   1722    UBool stringsContains(const UnicodeString &s) const;
   1723 
   1724    UnicodeString& _toPattern(UnicodeString& result,
   1725                              UBool escapeUnprintable) const;
   1726 
   1727    UnicodeString& _generatePattern(UnicodeString& result,
   1728                                    UBool escapeUnprintable) const;
   1729 
   1730    static void _appendToPat(UnicodeString& buf, const UnicodeString& s, UBool escapeUnprintable);
   1731 
   1732    static void _appendToPat(UnicodeString& buf, UChar32 c, UBool escapeUnprintable);
   1733 
   1734    static void _appendToPat(UnicodeString &result, UChar32 start, UChar32 end,
   1735                             UBool escapeUnprintable);
   1736 
   1737    //----------------------------------------------------------------
   1738    // Implementation: Fundamental operators
   1739    //----------------------------------------------------------------
   1740 
   1741    void exclusiveOr(const UChar32* other, int32_t otherLen, int8_t polarity);
   1742 
   1743    void add(const UChar32* other, int32_t otherLen, int8_t polarity);
   1744 
   1745    void retain(const UChar32* other, int32_t otherLen, int8_t polarity);
   1746 
   1747    /**
   1748     * Return true if the given position, in the given pattern, appears
   1749     * to be the start of a property set pattern [:foo:], \\p{foo}, or
   1750     * \\P{foo}, or \\N{name}.
   1751     */
   1752    static UBool resemblesPropertyPattern(const UnicodeString& pattern,
   1753                                          int32_t pos);
   1754 
   1755    static UBool resemblesPropertyPattern(RuleCharacterIterator& chars,
   1756                                          int32_t iterOpts);
   1757 
   1758    /**
   1759     * Parse the given property pattern at the given parse position
   1760     * and set this UnicodeSet to the result.
   1761     *
   1762     * The original design document is out of date, but still useful.
   1763     * Ignore the property and value names:
   1764     * https://htmlpreview.github.io/?https://github.com/unicode-org/icu-docs/blob/main/design/unicodeset_properties.html
   1765     *
   1766     * Recognized syntax:
   1767     *
   1768     * [:foo:] [:^foo:] - white space not allowed within "[:" or ":]"
   1769     * \\p{foo} \\P{foo}  - white space not allowed within "\\p" or "\\P"
   1770     * \\N{name}         - white space not allowed within "\\N"
   1771     *
   1772     * Other than the above restrictions, Unicode Pattern_White_Space characters are ignored.
   1773     * Case is ignored except in "\\p" and "\\P" and "\\N".  In 'name' leading
   1774     * and trailing space is deleted, and internal runs of whitespace
   1775     * are collapsed to a single space.
   1776     *
   1777     * We support binary properties, enumerated properties, and the
   1778     * following non-enumerated properties:
   1779     *
   1780     *  Numeric_Value
   1781     *  Name
   1782     *  Unicode_1_Name
   1783     *
   1784     * @param pattern the pattern string
   1785     * @param ppos on entry, the position at which to begin parsing.
   1786     * This should be one of the locations marked '^':
   1787     *
   1788     *   [:blah:]     \\p{blah}     \\P{blah}     \\N{name}
   1789     *   ^       %    ^       %    ^       %    ^       %
   1790     *
   1791     * On return, the position after the last character parsed, that is,
   1792     * the locations marked '%'.  If the parse fails, ppos is returned
   1793     * unchanged.
   1794     * @param ec status
   1795     * @return a reference to this.
   1796     */
   1797    UnicodeSet& applyPropertyPattern(const UnicodeString& pattern,
   1798                                     ParsePosition& ppos,
   1799                                     UErrorCode &ec);
   1800 
   1801    void applyPropertyPattern(RuleCharacterIterator& chars,
   1802                              UnicodeString& rebuiltPat,
   1803                              UErrorCode& ec);
   1804 
   1805    /**
   1806     * A filter that returns true if the given code point should be
   1807     * included in the UnicodeSet being constructed.
   1808     */
   1809    typedef UBool (*Filter)(UChar32 codePoint, void* context);
   1810 
   1811    /**
   1812     * Given a filter, set this UnicodeSet to the code points
   1813     * contained by that filter.  The filter MUST be
   1814     * property-conformant.  That is, if it returns value v for one
   1815     * code point, then it must return v for all affiliated code
   1816     * points, as defined by the inclusions list.  See
   1817     * getInclusions().
   1818     * src is a UPropertySource value.
   1819     */
   1820    void applyFilter(Filter filter,
   1821                     void* context,
   1822                     const UnicodeSet* inclusions,
   1823                     UErrorCode &status);
   1824 
   1825    /**
   1826     * Set the new pattern to cache.
   1827     */
   1828    void setPattern(const UnicodeString& newPat) {
   1829        setPattern(newPat.getBuffer(), newPat.length());
   1830    }
   1831    void setPattern(const char16_t *newPat, int32_t newPatLen);
   1832    /**
   1833     * Release existing cached pattern.
   1834     */
   1835    void releasePattern();
   1836 
   1837    friend class UnicodeSetIterator;
   1838 };
   1839 
   1840 
   1841 
   1842 inline bool UnicodeSet::operator!=(const UnicodeSet& o) const {
   1843    return !operator==(o);
   1844 }
   1845 
   1846 inline UBool UnicodeSet::isFrozen() const {
   1847    return bmpSet != nullptr || stringSpan != nullptr;
   1848 }
   1849 
   1850 inline UBool UnicodeSet::containsSome(UChar32 start, UChar32 end) const {
   1851    return !containsNone(start, end);
   1852 }
   1853 
   1854 inline UBool UnicodeSet::containsSome(const UnicodeSet& s) const {
   1855    return !containsNone(s);
   1856 }
   1857 
   1858 inline UBool UnicodeSet::containsSome(const UnicodeString& s) const {
   1859    return !containsNone(s);
   1860 }
   1861 
   1862 inline UBool UnicodeSet::isBogus() const {
   1863    return fFlags & kIsBogus;
   1864 }
   1865 
   1866 inline UnicodeSet *UnicodeSet::fromUSet(USet *uset) {
   1867    return reinterpret_cast<UnicodeSet *>(uset);
   1868 }
   1869 
   1870 inline const UnicodeSet *UnicodeSet::fromUSet(const USet *uset) {
   1871    return reinterpret_cast<const UnicodeSet *>(uset);
   1872 }
   1873 
   1874 inline USet *UnicodeSet::toUSet() {
   1875    return reinterpret_cast<USet *>(this);
   1876 }
   1877 
   1878 inline const USet *UnicodeSet::toUSet() const {
   1879    return reinterpret_cast<const USet *>(this);
   1880 }
   1881 
   1882 inline int32_t UnicodeSet::span(const UnicodeString &s, int32_t start, USetSpanCondition spanCondition) const {
   1883    int32_t sLength=s.length();
   1884    if(start<0) {
   1885        start=0;
   1886    } else if(start>sLength) {
   1887        start=sLength;
   1888    }
   1889    return start+span(s.getBuffer()+start, sLength-start, spanCondition);
   1890 }
   1891 
   1892 inline int32_t UnicodeSet::spanBack(const UnicodeString &s, int32_t limit, USetSpanCondition spanCondition) const {
   1893    int32_t sLength=s.length();
   1894    if(limit<0) {
   1895        limit=0;
   1896    } else if(limit>sLength) {
   1897        limit=sLength;
   1898    }
   1899    return spanBack(s.getBuffer(), limit, spanCondition);
   1900 }
   1901 
   1902 U_NAMESPACE_END
   1903 
   1904 #endif /* U_SHOW_CPLUSPLUS_API */
   1905 
   1906 #endif