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      1 /*
      2 ***************************************************************************
      3 * Copyright (C) 1999-2009, International Business Machines Corporation
      4 * and others. All Rights Reserved.
      5 ***************************************************************************
      6 *   Date        Name        Description
      7 *   10/20/99    alan        Creation.
      8 ***************************************************************************
      9 */
     10 
     11 #ifndef UNICODESET_H
     12 #define UNICODESET_H
     13 
     14 #include "unicode/unifilt.h"
     15 #include "unicode/unistr.h"
     16 #include "unicode/uset.h"
     17 
     18 /**
     19  * \file
     20  * \brief C++ API: Unicode Set
     21  */
     22 
     23 U_NAMESPACE_BEGIN
     24 
     25 class BMPSet;
     26 class ParsePosition;
     27 class SymbolTable;
     28 class UnicodeSetStringSpan;
     29 class UVector;
     30 class RuleCharacterIterator;
     31 
     32 /**
     33  * A mutable set of Unicode characters and multicharacter strings.  Objects of this class
     34  * represent <em>character classes</em> used in regular expressions.
     35  * A character specifies a subset of Unicode code points.  Legal
     36  * code points are U+0000 to U+10FFFF, inclusive.
     37  *
     38  * <p>The UnicodeSet class is not designed to be subclassed.
     39  *
     40  * <p><code>UnicodeSet</code> supports two APIs. The first is the
     41  * <em>operand</em> API that allows the caller to modify the value of
     42  * a <code>UnicodeSet</code> object. It conforms to Java 2's
     43  * <code>java.util.Set</code> interface, although
     44  * <code>UnicodeSet</code> does not actually implement that
     45  * interface. All methods of <code>Set</code> are supported, with the
     46  * modification that they take a character range or single character
     47  * instead of an <code>Object</code>, and they take a
     48  * <code>UnicodeSet</code> instead of a <code>Collection</code>.  The
     49  * operand API may be thought of in terms of boolean logic: a boolean
     50  * OR is implemented by <code>add</code>, a boolean AND is implemented
     51  * by <code>retain</code>, a boolean XOR is implemented by
     52  * <code>complement</code> taking an argument, and a boolean NOT is
     53  * implemented by <code>complement</code> with no argument.  In terms
     54  * of traditional set theory function names, <code>add</code> is a
     55  * union, <code>retain</code> is an intersection, <code>remove</code>
     56  * is an asymmetric difference, and <code>complement</code> with no
     57  * argument is a set complement with respect to the superset range
     58  * <code>MIN_VALUE-MAX_VALUE</code>
     59  *
     60  * <p>The second API is the
     61  * <code>applyPattern()</code>/<code>toPattern()</code> API from the
     62  * <code>java.text.Format</code>-derived classes.  Unlike the
     63  * methods that add characters, add categories, and control the logic
     64  * of the set, the method <code>applyPattern()</code> sets all
     65  * attributes of a <code>UnicodeSet</code> at once, based on a
     66  * string pattern.
     67  *
     68  * <p><b>Pattern syntax</b></p>
     69  *
     70  * Patterns are accepted by the constructors and the
     71  * <code>applyPattern()</code> methods and returned by the
     72  * <code>toPattern()</code> method.  These patterns follow a syntax
     73  * similar to that employed by version 8 regular expression character
     74  * classes.  Here are some simple examples:
     75  *
     76  * \htmlonly<blockquote>\endhtmlonly
     77  *   <table>
     78  *     <tr align="top">
     79  *       <td nowrap valign="top" align="left"><code>[]</code></td>
     80  *       <td valign="top">No characters</td>
     81  *     </tr><tr align="top">
     82  *       <td nowrap valign="top" align="left"><code>[a]</code></td>
     83  *       <td valign="top">The character 'a'</td>
     84  *     </tr><tr align="top">
     85  *       <td nowrap valign="top" align="left"><code>[ae]</code></td>
     86  *       <td valign="top">The characters 'a' and 'e'</td>
     87  *     </tr>
     88  *     <tr>
     89  *       <td nowrap valign="top" align="left"><code>[a-e]</code></td>
     90  *       <td valign="top">The characters 'a' through 'e' inclusive, in Unicode code
     91  *       point order</td>
     92  *     </tr>
     93  *     <tr>
     94  *       <td nowrap valign="top" align="left"><code>[\\u4E01]</code></td>
     95  *       <td valign="top">The character U+4E01</td>
     96  *     </tr>
     97  *     <tr>
     98  *       <td nowrap valign="top" align="left"><code>[a{ab}{ac}]</code></td>
     99  *       <td valign="top">The character 'a' and the multicharacter strings &quot;ab&quot; and
    100  *       &quot;ac&quot;</td>
    101  *     </tr>
    102  *     <tr>
    103  *       <td nowrap valign="top" align="left"><code>[\\p{Lu}]</code></td>
    104  *       <td valign="top">All characters in the general category Uppercase Letter</td>
    105  *     </tr>
    106  *   </table>
    107  * \htmlonly</blockquote>\endhtmlonly
    108  *
    109  * Any character may be preceded by a backslash in order to remove any special
    110  * meaning.  White space characters, as defined by UCharacter.isWhitespace(), are
    111  * ignored, unless they are escaped.
    112  *
    113  * <p>Property patterns specify a set of characters having a certain
    114  * property as defined by the Unicode standard.  Both the POSIX-like
    115  * "[:Lu:]" and the Perl-like syntax "\\p{Lu}" are recognized.  For a
    116  * complete list of supported property patterns, see the User's Guide
    117  * for UnicodeSet at
    118  * <a href="http://icu-project.org/userguide/unicodeSet.html">
    119  * http://icu-project.org/userguide/unicodeSet.html</a>.
    120  * Actual determination of property data is defined by the underlying
    121  * Unicode database as implemented by UCharacter.
    122  *
    123  * <p>Patterns specify individual characters, ranges of characters, and
    124  * Unicode property sets.  When elements are concatenated, they
    125  * specify their union.  To complement a set, place a '^' immediately
    126  * after the opening '['.  Property patterns are inverted by modifying
    127  * their delimiters; "[:^foo]" and "\\P{foo}".  In any other location,
    128  * '^' has no special meaning.
    129  *
    130  * <p>Ranges are indicated by placing two a '-' between two
    131  * characters, as in "a-z".  This specifies the range of all
    132  * characters from the left to the right, in Unicode order.  If the
    133  * left character is greater than or equal to the
    134  * right character it is a syntax error.  If a '-' occurs as the first
    135  * character after the opening '[' or '[^', or if it occurs as the
    136  * last character before the closing ']', then it is taken as a
    137  * literal.  Thus "[a\-b]", "[-ab]", and "[ab-]" all indicate the same
    138  * set of three characters, 'a', 'b', and '-'.
    139  *
    140  * <p>Sets may be intersected using the '&' operator or the asymmetric
    141  * set difference may be taken using the '-' operator, for example,
    142  * "[[:L:]&[\\u0000-\\u0FFF]]" indicates the set of all Unicode letters
    143  * with values less than 4096.  Operators ('&' and '|') have equal
    144  * precedence and bind left-to-right.  Thus
    145  * "[[:L:]-[a-z]-[\\u0100-\\u01FF]]" is equivalent to
    146  * "[[[:L:]-[a-z]]-[\\u0100-\\u01FF]]".  This only really matters for
    147  * difference; intersection is commutative.
    148  *
    149  * <table>
    150  * <tr valign=top><td nowrap><code>[a]</code><td>The set containing 'a'
    151  * <tr valign=top><td nowrap><code>[a-z]</code><td>The set containing 'a'
    152  * through 'z' and all letters in between, in Unicode order
    153  * <tr valign=top><td nowrap><code>[^a-z]</code><td>The set containing
    154  * all characters but 'a' through 'z',
    155  * that is, U+0000 through 'a'-1 and 'z'+1 through U+10FFFF
    156  * <tr valign=top><td nowrap><code>[[<em>pat1</em>][<em>pat2</em>]]</code>
    157  * <td>The union of sets specified by <em>pat1</em> and <em>pat2</em>
    158  * <tr valign=top><td nowrap><code>[[<em>pat1</em>]&[<em>pat2</em>]]</code>
    159  * <td>The intersection of sets specified by <em>pat1</em> and <em>pat2</em>
    160  * <tr valign=top><td nowrap><code>[[<em>pat1</em>]-[<em>pat2</em>]]</code>
    161  * <td>The asymmetric difference of sets specified by <em>pat1</em> and
    162  * <em>pat2</em>
    163  * <tr valign=top><td nowrap><code>[:Lu:] or \\p{Lu}</code>
    164  * <td>The set of characters having the specified
    165  * Unicode property; in
    166  * this case, Unicode uppercase letters
    167  * <tr valign=top><td nowrap><code>[:^Lu:] or \\P{Lu}</code>
    168  * <td>The set of characters <em>not</em> having the given
    169  * Unicode property
    170  * </table>
    171  *
    172  * <p><b>Warning</b>: you cannot add an empty string ("") to a UnicodeSet.</p>
    173  *
    174  * <p><b>Formal syntax</b></p>
    175  *
    176  * \htmlonly<blockquote>\endhtmlonly
    177  *   <table>
    178  *     <tr align="top">
    179  *       <td nowrap valign="top" align="right"><code>pattern :=&nbsp; </code></td>
    180  *       <td valign="top"><code>('[' '^'? item* ']') |
    181  *       property</code></td>
    182  *     </tr>
    183  *     <tr align="top">
    184  *       <td nowrap valign="top" align="right"><code>item :=&nbsp; </code></td>
    185  *       <td valign="top"><code>char | (char '-' char) | pattern-expr<br>
    186  *       </code></td>
    187  *     </tr>
    188  *     <tr align="top">
    189  *       <td nowrap valign="top" align="right"><code>pattern-expr :=&nbsp; </code></td>
    190  *       <td valign="top"><code>pattern | pattern-expr pattern |
    191  *       pattern-expr op pattern<br>
    192  *       </code></td>
    193  *     </tr>
    194  *     <tr align="top">
    195  *       <td nowrap valign="top" align="right"><code>op :=&nbsp; </code></td>
    196  *       <td valign="top"><code>'&amp;' | '-'<br>
    197  *       </code></td>
    198  *     </tr>
    199  *     <tr align="top">
    200  *       <td nowrap valign="top" align="right"><code>special :=&nbsp; </code></td>
    201  *       <td valign="top"><code>'[' | ']' | '-'<br>
    202  *       </code></td>
    203  *     </tr>
    204  *     <tr align="top">
    205  *       <td nowrap valign="top" align="right"><code>char :=&nbsp; </code></td>
    206  *       <td valign="top"><em>any character that is not</em><code> special<br>
    207  *       | ('\' </code><em>any character</em><code>)<br>
    208  *       | ('\\u' hex hex hex hex)<br>
    209  *       </code></td>
    210  *     </tr>
    211  *     <tr align="top">
    212  *       <td nowrap valign="top" align="right"><code>hex :=&nbsp; </code></td>
    213  *       <td valign="top"><em>any character for which
    214  *       </em><code>Character.digit(c, 16)</code><em>
    215  *       returns a non-negative result</em></td>
    216  *     </tr>
    217  *     <tr>
    218  *       <td nowrap valign="top" align="right"><code>property :=&nbsp; </code></td>
    219  *       <td valign="top"><em>a Unicode property set pattern</em></td>
    220  *     </tr>
    221  *   </table>
    222  *   <br>
    223  *   <table border="1">
    224  *     <tr>
    225  *       <td>Legend: <table>
    226  *         <tr>
    227  *           <td nowrap valign="top"><code>a := b</code></td>
    228  *           <td width="20" valign="top">&nbsp; </td>
    229  *           <td valign="top"><code>a</code> may be replaced by <code>b</code> </td>
    230  *         </tr>
    231  *         <tr>
    232  *           <td nowrap valign="top"><code>a?</code></td>
    233  *           <td valign="top"></td>
    234  *           <td valign="top">zero or one instance of <code>a</code><br>
    235  *           </td>
    236  *         </tr>
    237  *         <tr>
    238  *           <td nowrap valign="top"><code>a*</code></td>
    239  *           <td valign="top"></td>
    240  *           <td valign="top">one or more instances of <code>a</code><br>
    241  *           </td>
    242  *         </tr>
    243  *         <tr>
    244  *           <td nowrap valign="top"><code>a | b</code></td>
    245  *           <td valign="top"></td>
    246  *           <td valign="top">either <code>a</code> or <code>b</code><br>
    247  *           </td>
    248  *         </tr>
    249  *         <tr>
    250  *           <td nowrap valign="top"><code>'a'</code></td>
    251  *           <td valign="top"></td>
    252  *           <td valign="top">the literal string between the quotes </td>
    253  *         </tr>
    254  *       </table>
    255  *       </td>
    256  *     </tr>
    257  *   </table>
    258  * \htmlonly</blockquote>\endhtmlonly
    259  *
    260  * <p>Note:
    261  *  - Most UnicodeSet methods do not take a UErrorCode parameter because
    262  *   there are usually very few opportunities for failure other than a shortage
    263  *   of memory, error codes in low-level C++ string methods would be inconvenient,
    264  *   and the error code as the last parameter (ICU convention) would prevent
    265  *   the use of default parameter values.
    266  *   Instead, such methods set the UnicodeSet into a "bogus" state
    267  *   (see isBogus()) if an error occurs.
    268  *
    269  * @author Alan Liu
    270  * @stable ICU 2.0
    271  */
    272 class U_COMMON_API UnicodeSet : public UnicodeFilter {
    273 
    274     int32_t len; // length of list used; 0 <= len <= capacity
    275     int32_t capacity; // capacity of list
    276     UChar32* list; // MUST be terminated with HIGH
    277     BMPSet *bmpSet; // The set is frozen iff either bmpSet or stringSpan is not NULL.
    278     UChar32* buffer; // internal buffer, may be NULL
    279     int32_t bufferCapacity; // capacity of buffer
    280     int32_t patLen;
    281 
    282     /**
    283      * The pattern representation of this set.  This may not be the
    284      * most economical pattern.  It is the pattern supplied to
    285      * applyPattern(), with variables substituted and whitespace
    286      * removed.  For sets constructed without applyPattern(), or
    287      * modified using the non-pattern API, this string will be empty,
    288      * indicating that toPattern() must generate a pattern
    289      * representation from the inversion list.
    290      */
    291     UChar *pat;
    292     UVector* strings; // maintained in sorted order
    293     UnicodeSetStringSpan *stringSpan;
    294 
    295 private:
    296     enum { // constants
    297         kIsBogus = 1       // This set is bogus (i.e. not valid)
    298     };
    299     uint8_t fFlags;         // Bit flag (see constants above)
    300 public:
    301     /**
    302      * Determine if this object contains a valid set.
    303      * A bogus set has no value. It is different from an empty set.
    304      * It can be used to indicate that no set value is available.
    305      *
    306      * @return TRUE if the set is valid, FALSE otherwise
    307      * @see setToBogus()
    308      * @stable ICU 4.0
    309      */
    310     inline UBool isBogus(void) const;
    311 
    312     /**
    313      * Make this UnicodeSet object invalid.
    314      * The string will test TRUE with isBogus().
    315      *
    316      * A bogus set has no value. It is different from an empty set.
    317      * It can be used to indicate that no set value is available.
    318      *
    319      * This utility function is used throughout the UnicodeSet
    320      * implementation to indicate that a UnicodeSet operation failed,
    321      * and may be used in other functions,
    322      * especially but not exclusively when such functions do not
    323      * take a UErrorCode for simplicity.
    324      *
    325      * @see isBogus()
    326      * @stable ICU 4.0
    327      */
    328     void setToBogus();
    329 
    330 public:
    331 
    332     enum {
    333         /**
    334          * Minimum value that can be stored in a UnicodeSet.
    335          * @stable ICU 2.4
    336          */
    337         MIN_VALUE = 0,
    338 
    339         /**
    340          * Maximum value that can be stored in a UnicodeSet.
    341          * @stable ICU 2.4
    342          */
    343         MAX_VALUE = 0x10ffff
    344     };
    345 
    346     //----------------------------------------------------------------
    347     // Constructors &c
    348     //----------------------------------------------------------------
    349 
    350 public:
    351 
    352     /**
    353      * Constructs an empty set.
    354      * @stable ICU 2.0
    355      */
    356     UnicodeSet();
    357 
    358     /**
    359      * Constructs a set containing the given range. If <code>end >
    360      * start</code> then an empty set is created.
    361      *
    362      * @param start first character, inclusive, of range
    363      * @param end last character, inclusive, of range
    364      * @stable ICU 2.4
    365      */
    366     UnicodeSet(UChar32 start, UChar32 end);
    367 
    368     /**
    369      * Constructs a set from the given pattern.  See the class
    370      * description for the syntax of the pattern language.
    371      * @param pattern a string specifying what characters are in the set
    372      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
    373      * contains a syntax error.
    374      * @stable ICU 2.0
    375      */
    376     UnicodeSet(const UnicodeString& pattern,
    377                UErrorCode& status);
    378 
    379     /**
    380      * Constructs a set from the given pattern.  See the class
    381      * description for the syntax of the pattern language.
    382      * @param pattern a string specifying what characters are in the set
    383      * @param options bitmask for options to apply to the pattern.
    384      * Valid options are USET_IGNORE_SPACE and USET_CASE_INSENSITIVE.
    385      * @param symbols a symbol table mapping variable names to values
    386      * and stand-in characters to UnicodeSets; may be NULL
    387      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
    388      * contains a syntax error.
    389      * @internal
    390      */
    391     UnicodeSet(const UnicodeString& pattern,
    392                uint32_t options,
    393                const SymbolTable* symbols,
    394                UErrorCode& status);
    395 
    396     /**
    397      * Constructs a set from the given pattern.  See the class description
    398      * for the syntax of the pattern language.
    399      * @param pattern a string specifying what characters are in the set
    400      * @param pos on input, the position in pattern at which to start parsing.
    401      * On output, the position after the last character parsed.
    402      * @param options bitmask for options to apply to the pattern.
    403      * Valid options are USET_IGNORE_SPACE and USET_CASE_INSENSITIVE.
    404      * @param symbols a symbol table mapping variable names to values
    405      * and stand-in characters to UnicodeSets; may be NULL
    406      * @param status input-output error code
    407      * @stable ICU 2.8
    408      */
    409     UnicodeSet(const UnicodeString& pattern, ParsePosition& pos,
    410                uint32_t options,
    411                const SymbolTable* symbols,
    412                UErrorCode& status);
    413 
    414     /**
    415      * Constructs a set that is identical to the given UnicodeSet.
    416      * @stable ICU 2.0
    417      */
    418     UnicodeSet(const UnicodeSet& o);
    419 
    420     /**
    421      * Destructs the set.
    422      * @stable ICU 2.0
    423      */
    424     virtual ~UnicodeSet();
    425 
    426     /**
    427      * Assigns this object to be a copy of another.
    428      * A frozen set will not be modified.
    429      * @stable ICU 2.0
    430      */
    431     UnicodeSet& operator=(const UnicodeSet& o);
    432 
    433     /**
    434      * Compares the specified object with this set for equality.  Returns
    435      * <tt>true</tt> if the two sets
    436      * have the same size, and every member of the specified set is
    437      * contained in this set (or equivalently, every member of this set is
    438      * contained in the specified set).
    439      *
    440      * @param o set to be compared for equality with this set.
    441      * @return <tt>true</tt> if the specified set is equal to this set.
    442      * @stable ICU 2.0
    443      */
    444     virtual UBool operator==(const UnicodeSet& o) const;
    445 
    446     /**
    447      * Compares the specified object with this set for equality.  Returns
    448      * <tt>true</tt> if the specified set is not equal to this set.
    449      * @stable ICU 2.0
    450      */
    451     UBool operator!=(const UnicodeSet& o) const;
    452 
    453     /**
    454      * Returns a copy of this object.  All UnicodeFunctor objects have
    455      * to support cloning in order to allow classes using
    456      * UnicodeFunctors, such as Transliterator, to implement cloning.
    457      * If this set is frozen, then the clone will be frozen as well.
    458      * Use cloneAsThawed() for a mutable clone of a frozen set.
    459      * @see cloneAsThawed
    460      * @stable ICU 2.0
    461      */
    462     virtual UnicodeFunctor* clone() const;
    463 
    464     /**
    465      * Returns the hash code value for this set.
    466      *
    467      * @return the hash code value for this set.
    468      * @see Object#hashCode()
    469      * @stable ICU 2.0
    470      */
    471     virtual int32_t hashCode(void) const;
    472 
    473     /**
    474      * Get a UnicodeSet pointer from a USet
    475      *
    476      * @param uset a USet (the ICU plain C type for UnicodeSet)
    477      * @return the corresponding UnicodeSet pointer.
    478      *
    479      * @draft ICU 4.2
    480      */
    481     inline static UnicodeSet *fromUSet(USet *uset);
    482 
    483     /**
    484      * Get a UnicodeSet pointer from a const USet
    485      *
    486      * @param uset a const USet (the ICU plain C type for UnicodeSet)
    487      * @return the corresponding UnicodeSet pointer.
    488      *
    489      * @draft ICU 4.2
    490      */
    491     inline static const UnicodeSet *fromUSet(const USet *uset);
    492 
    493     /**
    494      * Produce a USet * pointer for this UnicodeSet.
    495      * USet is the plain C type for UnicodeSet
    496      *
    497      * @return a USet pointer for this UnicodeSet
    498      * @draft ICU 4.2
    499      */
    500     inline USet *toUSet();
    501 
    502 
    503     /**
    504      * Produce a const USet * pointer for this UnicodeSet.
    505      * USet is the plain C type for UnicodeSet
    506      *
    507      * @return a const USet pointer for this UnicodeSet
    508      * @draft ICU 4.2
    509      */
    510     inline const USet * toUSet() const;
    511 
    512 
    513     //----------------------------------------------------------------
    514     // Freezable API
    515     //----------------------------------------------------------------
    516 
    517     /**
    518      * Determines whether the set has been frozen (made immutable) or not.
    519      * See the ICU4J Freezable interface for details.
    520      * @return TRUE/FALSE for whether the set has been frozen
    521      * @see freeze
    522      * @see cloneAsThawed
    523      * @stable ICU 3.8
    524      */
    525     inline UBool isFrozen() const;
    526 
    527     /**
    528      * Freeze the set (make it immutable).
    529      * Once frozen, it cannot be unfrozen and is therefore thread-safe
    530      * until it is deleted.
    531      * See the ICU4J Freezable interface for details.
    532      * Freezing the set may also make some operations faster, for example
    533      * contains() and span().
    534      * A frozen set will not be modified. (It remains frozen.)
    535      * @return this set.
    536      * @see isFrozen
    537      * @see cloneAsThawed
    538      * @stable ICU 3.8
    539      */
    540     UnicodeFunctor *freeze();
    541 
    542     /**
    543      * Clone the set and make the clone mutable.
    544      * See the ICU4J Freezable interface for details.
    545      * @return the mutable clone
    546      * @see freeze
    547      * @see isFrozen
    548      * @stable ICU 3.8
    549      */
    550     UnicodeFunctor *cloneAsThawed() const;
    551 
    552     //----------------------------------------------------------------
    553     // Public API
    554     //----------------------------------------------------------------
    555 
    556     /**
    557      * Make this object represent the range <code>start - end</code>.
    558      * If <code>end > start</code> then this object is set to an
    559      * an empty range.
    560      * A frozen set will not be modified.
    561      *
    562      * @param start first character in the set, inclusive
    563      * @param end last character in the set, inclusive
    564      * @stable ICU 2.4
    565      */
    566     UnicodeSet& set(UChar32 start, UChar32 end);
    567 
    568     /**
    569      * Return true if the given position, in the given pattern, appears
    570      * to be the start of a UnicodeSet pattern.
    571      * @stable ICU 2.4
    572      */
    573     static UBool resemblesPattern(const UnicodeString& pattern,
    574                                   int32_t pos);
    575 
    576     /**
    577      * Modifies this set to represent the set specified by the given
    578      * pattern, optionally ignoring white space.  See the class
    579      * description for the syntax of the pattern language.
    580      * A frozen set will not be modified.
    581      * @param pattern a string specifying what characters are in the set
    582      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
    583      * contains a syntax error.
    584      * <em> Empties the set passed before applying the pattern.</em>
    585      * @return a reference to this
    586      * @stable ICU 2.0
    587      */
    588     UnicodeSet& applyPattern(const UnicodeString& pattern,
    589                              UErrorCode& status);
    590 
    591     /**
    592      * Modifies this set to represent the set specified by the given
    593      * pattern, optionally ignoring white space.  See the class
    594      * description for the syntax of the pattern language.
    595      * A frozen set will not be modified.
    596      * @param pattern a string specifying what characters are in the set
    597      * @param options bitmask for options to apply to the pattern.
    598      * Valid options are USET_IGNORE_SPACE and USET_CASE_INSENSITIVE.
    599      * @param symbols a symbol table mapping variable names to
    600      * values and stand-ins to UnicodeSets; may be NULL
    601      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
    602      * contains a syntax error.
    603      *<em> Empties the set passed before applying the pattern.</em>
    604      * @return a reference to this
    605      * @internal
    606      */
    607     UnicodeSet& applyPattern(const UnicodeString& pattern,
    608                              uint32_t options,
    609                              const SymbolTable* symbols,
    610                              UErrorCode& status);
    611 
    612     /**
    613      * Parses the given pattern, starting at the given position.  The
    614      * character at pattern.charAt(pos.getIndex()) must be '[', or the
    615      * parse fails.  Parsing continues until the corresponding closing
    616      * ']'.  If a syntax error is encountered between the opening and
    617      * closing brace, the parse fails.  Upon return from a successful
    618      * parse, the ParsePosition is updated to point to the character
    619      * following the closing ']', and a StringBuffer containing a
    620      * pairs list for the parsed pattern is returned.  This method calls
    621      * itself recursively to parse embedded subpatterns.
    622      *<em> Empties the set passed before applying the pattern.</em>
    623      * A frozen set will not be modified.
    624      *
    625      * @param pattern the string containing the pattern to be parsed.
    626      * The portion of the string from pos.getIndex(), which must be a
    627      * '[', to the corresponding closing ']', is parsed.
    628      * @param pos upon entry, the position at which to being parsing.
    629      * The character at pattern.charAt(pos.getIndex()) must be a '['.
    630      * Upon return from a successful parse, pos.getIndex() is either
    631      * the character after the closing ']' of the parsed pattern, or
    632      * pattern.length() if the closing ']' is the last character of
    633      * the pattern string.
    634      * @param options bitmask for options to apply to the pattern.
    635      * Valid options are USET_IGNORE_SPACE and USET_CASE_INSENSITIVE.
    636      * @param symbols a symbol table mapping variable names to
    637      * values and stand-ins to UnicodeSets; may be NULL
    638      * @param status returns <code>U_ILLEGAL_ARGUMENT_ERROR</code> if the pattern
    639      * contains a syntax error.
    640      * @return a reference to this
    641      * @stable ICU 2.8
    642      */
    643     UnicodeSet& applyPattern(const UnicodeString& pattern,
    644                              ParsePosition& pos,
    645                              uint32_t options,
    646                              const SymbolTable* symbols,
    647                              UErrorCode& status);
    648 
    649     /**
    650      * Returns a string representation of this set.  If the result of
    651      * calling this function is passed to a UnicodeSet constructor, it
    652      * will produce another set that is equal to this one.
    653      * A frozen set will not be modified.
    654      * @param result the string to receive the rules.  Previous
    655      * contents will be deleted.
    656      * @param escapeUnprintable if TRUE then convert unprintable
    657      * character to their hex escape representations, \\uxxxx or
    658      * \\Uxxxxxxxx.  Unprintable characters are those other than
    659      * U+000A, U+0020..U+007E.
    660      * @stable ICU 2.0
    661      */
    662     virtual UnicodeString& toPattern(UnicodeString& result,
    663                              UBool escapeUnprintable = FALSE) const;
    664 
    665     /**
    666      * Modifies this set to contain those code points which have the given value
    667      * for the given binary or enumerated property, as returned by
    668      * u_getIntPropertyValue.  Prior contents of this set are lost.
    669      * A frozen set will not be modified.
    670      *
    671      * @param prop a property in the range UCHAR_BIN_START..UCHAR_BIN_LIMIT-1
    672      * or UCHAR_INT_START..UCHAR_INT_LIMIT-1
    673      * or UCHAR_MASK_START..UCHAR_MASK_LIMIT-1.
    674      *
    675      * @param value a value in the range u_getIntPropertyMinValue(prop)..
    676      * u_getIntPropertyMaxValue(prop), with one exception.  If prop is
    677      * UCHAR_GENERAL_CATEGORY_MASK, then value should not be a UCharCategory, but
    678      * rather a mask value produced by U_GET_GC_MASK().  This allows grouped
    679      * categories such as [:L:] to be represented.
    680      *
    681      * @param ec error code input/output parameter
    682      *
    683      * @return a reference to this set
    684      *
    685      * @stable ICU 2.4
    686      */
    687     UnicodeSet& applyIntPropertyValue(UProperty prop,
    688                                       int32_t value,
    689                                       UErrorCode& ec);
    690 
    691     /**
    692      * Modifies this set to contain those code points which have the
    693      * given value for the given property.  Prior contents of this
    694      * set are lost.
    695      * A frozen set will not be modified.
    696      *
    697      * @param prop a property alias, either short or long.  The name is matched
    698      * loosely.  See PropertyAliases.txt for names and a description of loose
    699      * matching.  If the value string is empty, then this string is interpreted
    700      * as either a General_Category value alias, a Script value alias, a binary
    701      * property alias, or a special ID.  Special IDs are matched loosely and
    702      * correspond to the following sets:
    703      *
    704      * "ANY" = [\\u0000-\\U0010FFFF],
    705      * "ASCII" = [\\u0000-\\u007F],
    706      * "Assigned" = [:^Cn:].
    707      *
    708      * @param value a value alias, either short or long.  The name is matched
    709      * loosely.  See PropertyValueAliases.txt for names and a description of
    710      * loose matching.  In addition to aliases listed, numeric values and
    711      * canonical combining classes may be expressed numerically, e.g., ("nv",
    712      * "0.5") or ("ccc", "220").  The value string may also be empty.
    713      *
    714      * @param ec error code input/output parameter
    715      *
    716      * @return a reference to this set
    717      *
    718      * @stable ICU 2.4
    719      */
    720     UnicodeSet& applyPropertyAlias(const UnicodeString& prop,
    721                                    const UnicodeString& value,
    722                                    UErrorCode& ec);
    723 
    724     /**
    725      * Returns the number of elements in this set (its cardinality).
    726      * Note than the elements of a set may include both individual
    727      * codepoints and strings.
    728      *
    729      * @return the number of elements in this set (its cardinality).
    730      * @stable ICU 2.0
    731      */
    732     virtual int32_t size(void) const;
    733 
    734     /**
    735      * Returns <tt>true</tt> if this set contains no elements.
    736      *
    737      * @return <tt>true</tt> if this set contains no elements.
    738      * @stable ICU 2.0
    739      */
    740     virtual UBool isEmpty(void) const;
    741 
    742     /**
    743      * Returns true if this set contains the given character.
    744      * This function works faster with a frozen set.
    745      * @param c character to be checked for containment
    746      * @return true if the test condition is met
    747      * @stable ICU 2.0
    748      */
    749     virtual UBool contains(UChar32 c) const;
    750 
    751     /**
    752      * Returns true if this set contains every character
    753      * of the given range.
    754      * @param start first character, inclusive, of the range
    755      * @param end last character, inclusive, of the range
    756      * @return true if the test condition is met
    757      * @stable ICU 2.0
    758      */
    759     virtual UBool contains(UChar32 start, UChar32 end) const;
    760 
    761     /**
    762      * Returns <tt>true</tt> if this set contains the given
    763      * multicharacter string.
    764      * @param s string to be checked for containment
    765      * @return <tt>true</tt> if this set contains the specified string
    766      * @stable ICU 2.4
    767      */
    768     UBool contains(const UnicodeString& s) const;
    769 
    770     /**
    771      * Returns true if this set contains all the characters and strings
    772      * of the given set.
    773      * @param c set to be checked for containment
    774      * @return true if the test condition is met
    775      * @stable ICU 2.4
    776      */
    777     virtual UBool containsAll(const UnicodeSet& c) const;
    778 
    779     /**
    780      * Returns true if this set contains all the characters
    781      * of the given string.
    782      * @param s string containing characters to be checked for containment
    783      * @return true if the test condition is met
    784      * @stable ICU 2.4
    785      */
    786     UBool containsAll(const UnicodeString& s) const;
    787 
    788     /**
    789      * Returns true if this set contains none of the characters
    790      * of the given range.
    791      * @param start first character, inclusive, of the range
    792      * @param end last character, inclusive, of the range
    793      * @return true if the test condition is met
    794      * @stable ICU 2.4
    795      */
    796     UBool containsNone(UChar32 start, UChar32 end) const;
    797 
    798     /**
    799      * Returns true if this set contains none of the characters and strings
    800      * of the given set.
    801      * @param c set to be checked for containment
    802      * @return true if the test condition is met
    803      * @stable ICU 2.4
    804      */
    805     UBool containsNone(const UnicodeSet& c) const;
    806 
    807     /**
    808      * Returns true if this set contains none of the characters
    809      * of the given string.
    810      * @param s string containing characters to be checked for containment
    811      * @return true if the test condition is met
    812      * @stable ICU 2.4
    813      */
    814     UBool containsNone(const UnicodeString& s) const;
    815 
    816     /**
    817      * Returns true if this set contains one or more of the characters
    818      * in the given range.
    819      * @param start first character, inclusive, of the range
    820      * @param end last character, inclusive, of the range
    821      * @return true if the condition is met
    822      * @stable ICU 2.4
    823      */
    824     inline UBool containsSome(UChar32 start, UChar32 end) const;
    825 
    826     /**
    827      * Returns true if this set contains one or more of the characters
    828      * and strings of the given set.
    829      * @param s The set to be checked for containment
    830      * @return true if the condition is met
    831      * @stable ICU 2.4
    832      */
    833     inline UBool containsSome(const UnicodeSet& s) const;
    834 
    835     /**
    836      * Returns true if this set contains one or more of the characters
    837      * of the given string.
    838      * @param s string containing characters to be checked for containment
    839      * @return true if the condition is met
    840      * @stable ICU 2.4
    841      */
    842     inline UBool containsSome(const UnicodeString& s) const;
    843 
    844     /**
    845      * Returns the length of the initial substring of the input string which
    846      * consists only of characters and strings that are contained in this set
    847      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
    848      * or only of characters and strings that are not contained
    849      * in this set (USET_SPAN_NOT_CONTAINED).
    850      * See USetSpanCondition for details.
    851      * Similar to the strspn() C library function.
    852      * Unpaired surrogates are treated according to contains() of their surrogate code points.
    853      * This function works faster with a frozen set and with a non-negative string length argument.
    854      * @param s start of the string
    855      * @param length of the string; can be -1 for NUL-terminated
    856      * @param spanCondition specifies the containment condition
    857      * @return the length of the initial substring according to the spanCondition;
    858      *         0 if the start of the string does not fit the spanCondition
    859      * @stable ICU 3.8
    860      * @see USetSpanCondition
    861      */
    862     int32_t span(const UChar *s, int32_t length, USetSpanCondition spanCondition) const;
    863 
    864     /**
    865      * Returns the start of the trailing substring of the input string which
    866      * consists only of characters and strings that are contained in this set
    867      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
    868      * or only of characters and strings that are not contained
    869      * in this set (USET_SPAN_NOT_CONTAINED).
    870      * See USetSpanCondition for details.
    871      * Unpaired surrogates are treated according to contains() of their surrogate code points.
    872      * This function works faster with a frozen set and with a non-negative string length argument.
    873      * @param s start of the string
    874      * @param length of the string; can be -1 for NUL-terminated
    875      * @param spanCondition specifies the containment condition
    876      * @return the start of the trailing substring according to the spanCondition;
    877      *         the string length if the end of the string does not fit the spanCondition
    878      * @stable ICU 3.8
    879      * @see USetSpanCondition
    880      */
    881     int32_t spanBack(const UChar *s, int32_t length, USetSpanCondition spanCondition) const;
    882 
    883     /**
    884      * Returns the length of the initial substring of the input string which
    885      * consists only of characters and strings that are contained in this set
    886      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
    887      * or only of characters and strings that are not contained
    888      * in this set (USET_SPAN_NOT_CONTAINED).
    889      * See USetSpanCondition for details.
    890      * Similar to the strspn() C library function.
    891      * Malformed byte sequences are treated according to contains(0xfffd).
    892      * This function works faster with a frozen set and with a non-negative string length argument.
    893      * @param s start of the string (UTF-8)
    894      * @param length of the string; can be -1 for NUL-terminated
    895      * @param spanCondition specifies the containment condition
    896      * @return the length of the initial substring according to the spanCondition;
    897      *         0 if the start of the string does not fit the spanCondition
    898      * @stable ICU 3.8
    899      * @see USetSpanCondition
    900      */
    901     int32_t spanUTF8(const char *s, int32_t length, USetSpanCondition spanCondition) const;
    902 
    903     /**
    904      * Returns the start of the trailing substring of the input string which
    905      * consists only of characters and strings that are contained in this set
    906      * (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
    907      * or only of characters and strings that are not contained
    908      * in this set (USET_SPAN_NOT_CONTAINED).
    909      * See USetSpanCondition for details.
    910      * Malformed byte sequences are treated according to contains(0xfffd).
    911      * This function works faster with a frozen set and with a non-negative string length argument.
    912      * @param s start of the string (UTF-8)
    913      * @param length of the string; can be -1 for NUL-terminated
    914      * @param spanCondition specifies the containment condition
    915      * @return the start of the trailing substring according to the spanCondition;
    916      *         the string length if the end of the string does not fit the spanCondition
    917      * @stable ICU 3.8
    918      * @see USetSpanCondition
    919      */
    920     int32_t spanBackUTF8(const char *s, int32_t length, USetSpanCondition spanCondition) const;
    921 
    922     /**
    923      * Implement UnicodeMatcher::matches()
    924      * @stable ICU 2.4
    925      */
    926     virtual UMatchDegree matches(const Replaceable& text,
    927                          int32_t& offset,
    928                          int32_t limit,
    929                          UBool incremental);
    930 
    931 private:
    932     /**
    933      * Returns the longest match for s in text at the given position.
    934      * If limit > start then match forward from start+1 to limit
    935      * matching all characters except s.charAt(0).  If limit < start,
    936      * go backward starting from start-1 matching all characters
    937      * except s.charAt(s.length()-1).  This method assumes that the
    938      * first character, text.charAt(start), matches s, so it does not
    939      * check it.
    940      * @param text the text to match
    941      * @param start the first character to match.  In the forward
    942      * direction, text.charAt(start) is matched against s.charAt(0).
    943      * In the reverse direction, it is matched against
    944      * s.charAt(s.length()-1).
    945      * @param limit the limit offset for matching, either last+1 in
    946      * the forward direction, or last-1 in the reverse direction,
    947      * where last is the index of the last character to match.
    948      * @return If part of s matches up to the limit, return |limit -
    949      * start|.  If all of s matches before reaching the limit, return
    950      * s.length().  If there is a mismatch between s and text, return
    951      * 0
    952      */
    953     static int32_t matchRest(const Replaceable& text,
    954                              int32_t start, int32_t limit,
    955                              const UnicodeString& s);
    956 
    957     /**
    958      * Returns the smallest value i such that c < list[i].  Caller
    959      * must ensure that c is a legal value or this method will enter
    960      * an infinite loop.  This method performs a binary search.
    961      * @param c a character in the range MIN_VALUE..MAX_VALUE
    962      * inclusive
    963      * @return the smallest integer i in the range 0..len-1,
    964      * inclusive, such that c < list[i]
    965      */
    966     int32_t findCodePoint(UChar32 c) const;
    967 
    968 public:
    969 
    970     /**
    971      * Implementation of UnicodeMatcher API.  Union the set of all
    972      * characters that may be matched by this object into the given
    973      * set.
    974      * @param toUnionTo the set into which to union the source characters
    975      * @stable ICU 2.4
    976      */
    977     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const;
    978 
    979     /**
    980      * Returns the index of the given character within this set, where
    981      * the set is ordered by ascending code point.  If the character
    982      * is not in this set, return -1.  The inverse of this method is
    983      * <code>charAt()</code>.
    984      * @return an index from 0..size()-1, or -1
    985      * @stable ICU 2.4
    986      */
    987     int32_t indexOf(UChar32 c) const;
    988 
    989     /**
    990      * Returns the character at the given index within this set, where
    991      * the set is ordered by ascending code point.  If the index is
    992      * out of range, return (UChar32)-1.  The inverse of this method is
    993      * <code>indexOf()</code>.
    994      * @param index an index from 0..size()-1
    995      * @return the character at the given index, or (UChar32)-1.
    996      * @stable ICU 2.4
    997      */
    998     UChar32 charAt(int32_t index) const;
    999 
   1000     /**
   1001      * Adds the specified range to this set if it is not already
   1002      * present.  If this set already contains the specified range,
   1003      * the call leaves this set unchanged.  If <code>end > start</code>
   1004      * then an empty range is added, leaving the set unchanged.
   1005      * This is equivalent to a boolean logic OR, or a set UNION.
   1006      * A frozen set will not be modified.
   1007      *
   1008      * @param start first character, inclusive, of range to be added
   1009      * to this set.
   1010      * @param end last character, inclusive, of range to be added
   1011      * to this set.
   1012      * @stable ICU 2.0
   1013      */
   1014     virtual UnicodeSet& add(UChar32 start, UChar32 end);
   1015 
   1016     /**
   1017      * Adds the specified character to this set if it is not already
   1018      * present.  If this set already contains the specified character,
   1019      * the call leaves this set unchanged.
   1020      * A frozen set will not be modified.
   1021      * @stable ICU 2.0
   1022      */
   1023     UnicodeSet& add(UChar32 c);
   1024 
   1025     /**
   1026      * Adds the specified multicharacter to this set if it is not already
   1027      * present.  If this set already contains the multicharacter,
   1028      * the call leaves this set unchanged.
   1029      * Thus "ch" => {"ch"}
   1030      * <br><b>Warning: you cannot add an empty string ("") to a UnicodeSet.</b>
   1031      * A frozen set will not be modified.
   1032      * @param s the source string
   1033      * @return this object, for chaining
   1034      * @stable ICU 2.4
   1035      */
   1036     UnicodeSet& add(const UnicodeString& s);
   1037 
   1038  private:
   1039     /**
   1040      * @return a code point IF the string consists of a single one.
   1041      * otherwise returns -1.
   1042      * @param s string to test
   1043      */
   1044     static int32_t getSingleCP(const UnicodeString& s);
   1045 
   1046     void _add(const UnicodeString& s);
   1047 
   1048  public:
   1049     /**
   1050      * Adds each of the characters in this string to the set. Thus "ch" => {"c", "h"}
   1051      * If this set already any particular character, it has no effect on that character.
   1052      * A frozen set will not be modified.
   1053      * @param s the source string
   1054      * @return this object, for chaining
   1055      * @stable ICU 2.4
   1056      */
   1057     UnicodeSet& addAll(const UnicodeString& s);
   1058 
   1059     /**
   1060      * Retains EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1061      * If this set already any particular character, it has no effect on that character.
   1062      * A frozen set will not be modified.
   1063      * @param s the source string
   1064      * @return this object, for chaining
   1065      * @stable ICU 2.4
   1066      */
   1067     UnicodeSet& retainAll(const UnicodeString& s);
   1068 
   1069     /**
   1070      * Complement EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1071      * If this set already any particular character, it has no effect on that character.
   1072      * A frozen set will not be modified.
   1073      * @param s the source string
   1074      * @return this object, for chaining
   1075      * @stable ICU 2.4
   1076      */
   1077     UnicodeSet& complementAll(const UnicodeString& s);
   1078 
   1079     /**
   1080      * Remove EACH of the characters in this string. Note: "ch" == {"c", "h"}
   1081      * If this set already any particular character, it has no effect on that character.
   1082      * A frozen set will not be modified.
   1083      * @param s the source string
   1084      * @return this object, for chaining
   1085      * @stable ICU 2.4
   1086      */
   1087     UnicodeSet& removeAll(const UnicodeString& s);
   1088 
   1089     /**
   1090      * Makes a set from a multicharacter string. Thus "ch" => {"ch"}
   1091      * <br><b>Warning: you cannot add an empty string ("") to a UnicodeSet.</b>
   1092      * @param s the source string
   1093      * @return a newly created set containing the given string.
   1094      * The caller owns the return object and is responsible for deleting it.
   1095      * @stable ICU 2.4
   1096      */
   1097     static UnicodeSet* U_EXPORT2 createFrom(const UnicodeString& s);
   1098 
   1099 
   1100     /**
   1101      * Makes a set from each of the characters in the string. Thus "ch" => {"c", "h"}
   1102      * @param s the source string
   1103      * @return a newly created set containing the given characters
   1104      * The caller owns the return object and is responsible for deleting it.
   1105      * @stable ICU 2.4
   1106      */
   1107     static UnicodeSet* U_EXPORT2 createFromAll(const UnicodeString& s);
   1108 
   1109     /**
   1110      * Retain only the elements in this set that are contained in the
   1111      * specified range.  If <code>end > start</code> then an empty range is
   1112      * retained, leaving the set empty.  This is equivalent to
   1113      * a boolean logic AND, or a set INTERSECTION.
   1114      * A frozen set will not be modified.
   1115      *
   1116      * @param start first character, inclusive, of range to be retained
   1117      * to this set.
   1118      * @param end last character, inclusive, of range to be retained
   1119      * to this set.
   1120      * @stable ICU 2.0
   1121      */
   1122     virtual UnicodeSet& retain(UChar32 start, UChar32 end);
   1123 
   1124 
   1125     /**
   1126      * Retain the specified character from this set if it is present.
   1127      * A frozen set will not be modified.
   1128      * @stable ICU 2.0
   1129      */
   1130     UnicodeSet& retain(UChar32 c);
   1131 
   1132     /**
   1133      * Removes the specified range from this set if it is present.
   1134      * The set will not contain the specified range once the call
   1135      * returns.  If <code>end > start</code> then an empty range is
   1136      * removed, leaving the set unchanged.
   1137      * A frozen set will not be modified.
   1138      *
   1139      * @param start first character, inclusive, of range to be removed
   1140      * from this set.
   1141      * @param end last character, inclusive, of range to be removed
   1142      * from this set.
   1143      * @stable ICU 2.0
   1144      */
   1145     virtual UnicodeSet& remove(UChar32 start, UChar32 end);
   1146 
   1147     /**
   1148      * Removes the specified character from this set if it is present.
   1149      * The set will not contain the specified range once the call
   1150      * returns.
   1151      * A frozen set will not be modified.
   1152      * @stable ICU 2.0
   1153      */
   1154     UnicodeSet& remove(UChar32 c);
   1155 
   1156     /**
   1157      * Removes the specified string from this set if it is present.
   1158      * The set will not contain the specified character once the call
   1159      * returns.
   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& remove(const UnicodeString& s);
   1166 
   1167     /**
   1168      * Inverts this set.  This operation modifies this set so that
   1169      * its value is its complement.  This is equivalent to
   1170      * <code>complement(MIN_VALUE, MAX_VALUE)</code>.
   1171      * A frozen set will not be modified.
   1172      * @stable ICU 2.0
   1173      */
   1174     virtual UnicodeSet& complement(void);
   1175 
   1176     /**
   1177      * Complements the specified range in this set.  Any character in
   1178      * the range will be removed if it is in this set, or will be
   1179      * added if it is not in this set.  If <code>end > start</code>
   1180      * then an empty range is complemented, leaving the set unchanged.
   1181      * This is equivalent to a boolean logic XOR.
   1182      * A frozen set will not be modified.
   1183      *
   1184      * @param start first character, inclusive, of range to be removed
   1185      * from this set.
   1186      * @param end last character, inclusive, of range to be removed
   1187      * from this set.
   1188      * @stable ICU 2.0
   1189      */
   1190     virtual UnicodeSet& complement(UChar32 start, UChar32 end);
   1191 
   1192     /**
   1193      * Complements the specified character in this set.  The character
   1194      * will be removed if it is in this set, or will be added if it is
   1195      * not in this set.
   1196      * A frozen set will not be modified.
   1197      * @stable ICU 2.0
   1198      */
   1199     UnicodeSet& complement(UChar32 c);
   1200 
   1201     /**
   1202      * Complement the specified string in this set.
   1203      * The set will not contain the specified string once the call
   1204      * returns.
   1205      * <br><b>Warning: you cannot add an empty string ("") to a UnicodeSet.</b>
   1206      * A frozen set will not be modified.
   1207      * @param s the string to complement
   1208      * @return this object, for chaining
   1209      * @stable ICU 2.4
   1210      */
   1211     UnicodeSet& complement(const UnicodeString& s);
   1212 
   1213     /**
   1214      * Adds all of the elements in the specified set to this set if
   1215      * they're not already present.  This operation effectively
   1216      * modifies this set so that its value is the <i>union</i> of the two
   1217      * sets.  The behavior of this operation is unspecified if the specified
   1218      * collection is modified while the operation is in progress.
   1219      * A frozen set will not be modified.
   1220      *
   1221      * @param c set whose elements are to be added to this set.
   1222      * @see #add(UChar32, UChar32)
   1223      * @stable ICU 2.0
   1224      */
   1225     virtual UnicodeSet& addAll(const UnicodeSet& c);
   1226 
   1227     /**
   1228      * Retains only the elements in this set that are contained in the
   1229      * specified set.  In other words, removes from this set all of
   1230      * its elements that are not contained in the specified set.  This
   1231      * operation effectively modifies this set so that its value is
   1232      * the <i>intersection</i> of the two sets.
   1233      * A frozen set will not be modified.
   1234      *
   1235      * @param c set that defines which elements this set will retain.
   1236      * @stable ICU 2.0
   1237      */
   1238     virtual UnicodeSet& retainAll(const UnicodeSet& c);
   1239 
   1240     /**
   1241      * Removes from this set all of its elements that are contained in the
   1242      * specified set.  This operation effectively modifies this
   1243      * set so that its value is the <i>asymmetric set difference</i> of
   1244      * the two sets.
   1245      * A frozen set will not be modified.
   1246      *
   1247      * @param c set that defines which elements will be removed from
   1248      *          this set.
   1249      * @stable ICU 2.0
   1250      */
   1251     virtual UnicodeSet& removeAll(const UnicodeSet& c);
   1252 
   1253     /**
   1254      * Complements in this set all elements contained in the specified
   1255      * set.  Any character in the other set will be removed if it is
   1256      * in this set, or will be added if it is not in this set.
   1257      * A frozen set will not be modified.
   1258      *
   1259      * @param c set that defines which elements will be xor'ed from
   1260      *          this set.
   1261      * @stable ICU 2.4
   1262      */
   1263     virtual UnicodeSet& complementAll(const UnicodeSet& c);
   1264 
   1265     /**
   1266      * Removes all of the elements from this set.  This set will be
   1267      * empty after this call returns.
   1268      * A frozen set will not be modified.
   1269      * @stable ICU 2.0
   1270      */
   1271     virtual UnicodeSet& clear(void);
   1272 
   1273     /**
   1274      * Close this set over the given attribute.  For the attribute
   1275      * USET_CASE, the result is to modify this set so that:
   1276      *
   1277      * 1. For each character or string 'a' in this set, all strings or
   1278      * characters 'b' such that foldCase(a) == foldCase(b) are added
   1279      * to this set.
   1280      *
   1281      * 2. For each string 'e' in the resulting set, if e !=
   1282      * foldCase(e), 'e' will be removed.
   1283      *
   1284      * Example: [aq\\u00DF{Bc}{bC}{Fi}] => [aAqQ\\u00DF\\uFB01{ss}{bc}{fi}]
   1285      *
   1286      * (Here foldCase(x) refers to the operation u_strFoldCase, and a
   1287      * == b denotes that the contents are the same, not pointer
   1288      * comparison.)
   1289      *
   1290      * A frozen set will not be modified.
   1291      *
   1292      * @param attribute bitmask for attributes to close over.
   1293      * Currently only the USET_CASE bit is supported.  Any undefined bits
   1294      * are ignored.
   1295      * @return a reference to this set.
   1296      * @draft ICU 4.2
   1297      */
   1298     UnicodeSet& closeOver(int32_t attribute);
   1299 
   1300     /**
   1301      * Remove all strings from this set.
   1302      *
   1303      * @return a reference to this set.
   1304      * @draft ICU 4.2
   1305      */
   1306     virtual UnicodeSet &removeAllStrings();
   1307 
   1308     /**
   1309      * Iteration method that returns the number of ranges contained in
   1310      * this set.
   1311      * @see #getRangeStart
   1312      * @see #getRangeEnd
   1313      * @stable ICU 2.4
   1314      */
   1315     virtual int32_t getRangeCount(void) const;
   1316 
   1317     /**
   1318      * Iteration method that returns the first character in the
   1319      * specified range of this set.
   1320      * @see #getRangeCount
   1321      * @see #getRangeEnd
   1322      * @stable ICU 2.4
   1323      */
   1324     virtual UChar32 getRangeStart(int32_t index) const;
   1325 
   1326     /**
   1327      * Iteration method that returns the last character in the
   1328      * specified range of this set.
   1329      * @see #getRangeStart
   1330      * @see #getRangeEnd
   1331      * @stable ICU 2.4
   1332      */
   1333     virtual UChar32 getRangeEnd(int32_t index) const;
   1334 
   1335     /**
   1336      * Serializes this set into an array of 16-bit integers.  Serialization
   1337      * (currently) only records the characters in the set; multicharacter
   1338      * strings are ignored.
   1339      *
   1340      * The array has following format (each line is one 16-bit
   1341      * integer):
   1342      *
   1343      *  length     = (n+2*m) | (m!=0?0x8000:0)
   1344      *  bmpLength  = n; present if m!=0
   1345      *  bmp[0]
   1346      *  bmp[1]
   1347      *  ...
   1348      *  bmp[n-1]
   1349      *  supp-high[0]
   1350      *  supp-low[0]
   1351      *  supp-high[1]
   1352      *  supp-low[1]
   1353      *  ...
   1354      *  supp-high[m-1]
   1355      *  supp-low[m-1]
   1356      *
   1357      * The array starts with a header.  After the header are n bmp
   1358      * code points, then m supplementary code points.  Either n or m
   1359      * or both may be zero.  n+2*m is always <= 0x7FFF.
   1360      *
   1361      * If there are no supplementary characters (if m==0) then the
   1362      * header is one 16-bit integer, 'length', with value n.
   1363      *
   1364      * If there are supplementary characters (if m!=0) then the header
   1365      * is two 16-bit integers.  The first, 'length', has value
   1366      * (n+2*m)|0x8000.  The second, 'bmpLength', has value n.
   1367      *
   1368      * After the header the code points are stored in ascending order.
   1369      * Supplementary code points are stored as most significant 16
   1370      * bits followed by least significant 16 bits.
   1371      *
   1372      * @param dest pointer to buffer of destCapacity 16-bit integers.
   1373      * May be NULL only if destCapacity is zero.
   1374      * @param destCapacity size of dest, or zero.  Must not be negative.
   1375      * @param ec error code.  Will be set to U_INDEX_OUTOFBOUNDS_ERROR
   1376      * if n+2*m > 0x7FFF.  Will be set to U_BUFFER_OVERFLOW_ERROR if
   1377      * n+2*m+(m!=0?2:1) > destCapacity.
   1378      * @return the total length of the serialized format, including
   1379      * the header, that is, n+2*m+(m!=0?2:1), or 0 on error other
   1380      * than U_BUFFER_OVERFLOW_ERROR.
   1381      * @stable ICU 2.4
   1382      */
   1383     int32_t serialize(uint16_t *dest, int32_t destCapacity, UErrorCode& ec) const;
   1384 
   1385     /**
   1386      * Reallocate this objects internal structures to take up the least
   1387      * possible space, without changing this object's value.
   1388      * A frozen set will not be modified.
   1389      * @stable ICU 2.4
   1390      */
   1391     virtual UnicodeSet& compact();
   1392 
   1393     /**
   1394      * Return the class ID for this class.  This is useful only for
   1395      * comparing to a return value from getDynamicClassID().  For example:
   1396      * <pre>
   1397      * .      Base* polymorphic_pointer = createPolymorphicObject();
   1398      * .      if (polymorphic_pointer->getDynamicClassID() ==
   1399      * .          Derived::getStaticClassID()) ...
   1400      * </pre>
   1401      * @return          The class ID for all objects of this class.
   1402      * @stable ICU 2.0
   1403      */
   1404     static UClassID U_EXPORT2 getStaticClassID(void);
   1405 
   1406     /**
   1407      * Implement UnicodeFunctor API.
   1408      *
   1409      * @return The class ID for this object. All objects of a given
   1410      * class have the same class ID.  Objects of other classes have
   1411      * different class IDs.
   1412      * @stable ICU 2.4
   1413      */
   1414     virtual UClassID getDynamicClassID(void) const;
   1415 
   1416 private:
   1417 
   1418     // Private API for the USet API
   1419 
   1420     friend class USetAccess;
   1421 
   1422     int32_t getStringCount() const;
   1423 
   1424     const UnicodeString* getString(int32_t index) const;
   1425 
   1426     //----------------------------------------------------------------
   1427     // RuleBasedTransliterator support
   1428     //----------------------------------------------------------------
   1429 
   1430 private:
   1431 
   1432     /**
   1433      * Returns <tt>true</tt> if this set contains any character whose low byte
   1434      * is the given value.  This is used by <tt>RuleBasedTransliterator</tt> for
   1435      * indexing.
   1436      */
   1437     virtual UBool matchesIndexValue(uint8_t v) const;
   1438 
   1439 private:
   1440 
   1441     //----------------------------------------------------------------
   1442     // Implementation: Clone as thawed (see ICU4J Freezable)
   1443     //----------------------------------------------------------------
   1444 
   1445     UnicodeSet(const UnicodeSet& o, UBool /* asThawed */);
   1446 
   1447     //----------------------------------------------------------------
   1448     // Implementation: Pattern parsing
   1449     //----------------------------------------------------------------
   1450 
   1451     void applyPattern(RuleCharacterIterator& chars,
   1452                       const SymbolTable* symbols,
   1453                       UnicodeString& rebuiltPat,
   1454                       uint32_t options,
   1455                       UErrorCode& ec);
   1456 
   1457     //----------------------------------------------------------------
   1458     // Implementation: Utility methods
   1459     //----------------------------------------------------------------
   1460 
   1461     void ensureCapacity(int32_t newLen, UErrorCode& ec);
   1462 
   1463     void ensureBufferCapacity(int32_t newLen, UErrorCode& ec);
   1464 
   1465     void swapBuffers(void);
   1466 
   1467     UBool allocateStrings(UErrorCode &status);
   1468 
   1469     UnicodeString& _toPattern(UnicodeString& result,
   1470                               UBool escapeUnprintable) const;
   1471 
   1472     UnicodeString& _generatePattern(UnicodeString& result,
   1473                                     UBool escapeUnprintable) const;
   1474 
   1475     static void _appendToPat(UnicodeString& buf, const UnicodeString& s, UBool escapeUnprintable);
   1476 
   1477     static void _appendToPat(UnicodeString& buf, UChar32 c, UBool escapeUnprintable);
   1478 
   1479     //----------------------------------------------------------------
   1480     // Implementation: Fundamental operators
   1481     //----------------------------------------------------------------
   1482 
   1483     void exclusiveOr(const UChar32* other, int32_t otherLen, int8_t polarity);
   1484 
   1485     void add(const UChar32* other, int32_t otherLen, int8_t polarity);
   1486 
   1487     void retain(const UChar32* other, int32_t otherLen, int8_t polarity);
   1488 
   1489     /**
   1490      * Return true if the given position, in the given pattern, appears
   1491      * to be the start of a property set pattern [:foo:], \\p{foo}, or
   1492      * \\P{foo}, or \\N{name}.
   1493      */
   1494     static UBool resemblesPropertyPattern(const UnicodeString& pattern,
   1495                                           int32_t pos);
   1496 
   1497     static UBool resemblesPropertyPattern(RuleCharacterIterator& chars,
   1498                                           int32_t iterOpts);
   1499 
   1500     /**
   1501      * Parse the given property pattern at the given parse position
   1502      * and set this UnicodeSet to the result.
   1503      *
   1504      * The original design document is out of date, but still useful.
   1505      * Ignore the property and value names:
   1506      * http://source.icu-project.org/repos/icu/icuhtml/trunk/design/unicodeset_properties.html
   1507      *
   1508      * Recognized syntax:
   1509      *
   1510      * [:foo:] [:^foo:] - white space not allowed within "[:" or ":]"
   1511      * \\p{foo} \\P{foo}  - white space not allowed within "\\p" or "\\P"
   1512      * \\N{name}         - white space not allowed within "\\N"
   1513      *
   1514      * Other than the above restrictions, white space is ignored.  Case
   1515      * is ignored except in "\\p" and "\\P" and "\\N".  In 'name' leading
   1516      * and trailing space is deleted, and internal runs of whitespace
   1517      * are collapsed to a single space.
   1518      *
   1519      * We support binary properties, enumerated properties, and the
   1520      * following non-enumerated properties:
   1521      *
   1522      *  Numeric_Value
   1523      *  Name
   1524      *  Unicode_1_Name
   1525      *
   1526      * @param pattern the pattern string
   1527      * @param ppos on entry, the position at which to begin parsing.
   1528      * This should be one of the locations marked '^':
   1529      *
   1530      *   [:blah:]     \\p{blah}     \\P{blah}     \\N{name}
   1531      *   ^       %    ^       %    ^       %    ^       %
   1532      *
   1533      * On return, the position after the last character parsed, that is,
   1534      * the locations marked '%'.  If the parse fails, ppos is returned
   1535      * unchanged.
   1536      * @return a reference to this.
   1537      */
   1538     UnicodeSet& applyPropertyPattern(const UnicodeString& pattern,
   1539                                      ParsePosition& ppos,
   1540                                      UErrorCode &ec);
   1541 
   1542     void applyPropertyPattern(RuleCharacterIterator& chars,
   1543                               UnicodeString& rebuiltPat,
   1544                               UErrorCode& ec);
   1545 
   1546     static const UnicodeSet* getInclusions(int32_t src, UErrorCode &status);
   1547 
   1548     /**
   1549      * A filter that returns TRUE if the given code point should be
   1550      * included in the UnicodeSet being constructed.
   1551      */
   1552     typedef UBool (*Filter)(UChar32 codePoint, void* context);
   1553 
   1554     /**
   1555      * Given a filter, set this UnicodeSet to the code points
   1556      * contained by that filter.  The filter MUST be
   1557      * property-conformant.  That is, if it returns value v for one
   1558      * code point, then it must return v for all affiliated code
   1559      * points, as defined by the inclusions list.  See
   1560      * getInclusions().
   1561      * src is a UPropertySource value.
   1562      */
   1563     void applyFilter(Filter filter,
   1564                      void* context,
   1565                      int32_t src,
   1566                      UErrorCode &status);
   1567 
   1568     /**
   1569      * Set the new pattern to cache.
   1570      */
   1571     void setPattern(const UnicodeString& newPat);
   1572     /**
   1573      * Release existing cached pattern.
   1574      */
   1575     void releasePattern();
   1576 
   1577     friend class UnicodeSetIterator;
   1578 };
   1579 
   1580 
   1581 
   1582 inline UBool UnicodeSet::operator!=(const UnicodeSet& o) const {
   1583     return !operator==(o);
   1584 }
   1585 
   1586 inline UBool UnicodeSet::isFrozen() const {
   1587     return (UBool)(bmpSet!=NULL || stringSpan!=NULL);
   1588 }
   1589 
   1590 inline UBool UnicodeSet::containsSome(UChar32 start, UChar32 end) const {
   1591     return !containsNone(start, end);
   1592 }
   1593 
   1594 inline UBool UnicodeSet::containsSome(const UnicodeSet& s) const {
   1595     return !containsNone(s);
   1596 }
   1597 
   1598 inline UBool UnicodeSet::containsSome(const UnicodeString& s) const {
   1599     return !containsNone(s);
   1600 }
   1601 
   1602 inline UBool UnicodeSet::isBogus() const {
   1603     return (UBool)(fFlags & kIsBogus);
   1604 }
   1605 
   1606 inline UnicodeSet *UnicodeSet::fromUSet(USet *uset) {
   1607     return reinterpret_cast<UnicodeSet *>(uset);
   1608 }
   1609 
   1610 inline const UnicodeSet *UnicodeSet::fromUSet(const USet *uset) {
   1611     return reinterpret_cast<const UnicodeSet *>(uset);
   1612 }
   1613 
   1614 inline USet *UnicodeSet::toUSet() {
   1615     return reinterpret_cast<USet *>(this);
   1616 }
   1617 
   1618 inline const USet *UnicodeSet::toUSet() const {
   1619     return reinterpret_cast<const USet *>(this);
   1620 }
   1621 
   1622 U_NAMESPACE_END
   1623 
   1624 #endif
   1625