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uset.h (64545B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*
*   Copyright (C) 2002-2014, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
*******************************************************************************
*   file name:  uset.h
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2002mar07
*   created by: Markus W. Scherer
*
*   C version of UnicodeSet.
*/


/**
* \file
* \brief C API: Unicode Set
*
* <p>This is a C wrapper around the C++ UnicodeSet class.</p>
*/

#ifndef __USET_H__
#define __USET_H__

#include "unicode/utypes.h"
#include "unicode/uchar.h"

#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
#include <string>
#include <string_view>
#include "unicode/char16ptr.h"
#include "unicode/localpointer.h"
#include "unicode/utf16.h"
#endif

#ifndef USET_DEFINED

#ifndef U_IN_DOXYGEN
#define USET_DEFINED
#endif
/**
* USet is the C API type corresponding to C++ class UnicodeSet.
* Use the uset_* API to manipulate.  Create with
* uset_open*, and destroy with uset_close.
* @stable ICU 2.4
*/
typedef struct USet USet;
#endif

/**
* Bitmask values to be passed to uset_openPatternOptions() or
* uset_applyPattern() taking an option parameter.
*
* Use at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
* These case options are mutually exclusive.
*
* Undefined options bits are ignored, and reserved for future use.
*
* @stable ICU 2.4
*/
enum {
   /**
    * Ignore white space within patterns unless quoted or escaped.
    * @stable ICU 2.4
    */
   USET_IGNORE_SPACE = 1,

   /**
    * Enable case insensitive matching.  E.g., "[ab]" with this flag
    * will match 'a', 'A', 'b', and 'B'.  "[^ab]" with this flag will
    * match all except 'a', 'A', 'b', and 'B'. This performs a full
    * closure over case mappings, e.g. 'ſ' (U+017F long s) for 's'.
    *
    * The resulting set is a superset of the input for the code points but
    * not for the strings.
    * It performs a case mapping closure of the code points and adds
    * full case folding strings for the code points, and reduces strings of
    * the original set to their full case folding equivalents.
    *
    * This is designed for case-insensitive matches, for example
    * in regular expressions. The full code point case closure allows checking of
    * an input character directly against the closure set.
    * Strings are matched by comparing the case-folded form from the closure
    * set with an incremental case folding of the string in question.
    *
    * The closure set will also contain single code points if the original
    * set contained case-equivalent strings (like U+00DF for "ss" or "Ss" etc.).
    * This is not necessary (that is, redundant) for the above matching method
    * but results in the same closure sets regardless of whether the original
    * set contained the code point or a string.
    *
    * @stable ICU 2.4
    */
   USET_CASE_INSENSITIVE = 2,

   /**
    * Adds all case mappings for each element in the set.
    * This adds the full lower-, title-, and uppercase mappings as well as the full case folding
    * of each existing element in the set.
    *
    * Unlike the “case insensitive” options, this does not perform a closure.
    * For example, it does not add 'ſ' (U+017F long s) for 's',
    * 'K' (U+212A Kelvin sign) for 'k', or replace set strings by their case-folded versions.
    *
    * @stable ICU 3.2
    */
   USET_ADD_CASE_MAPPINGS = 4,

   /**
    * Enable case insensitive matching.
    * Same as USET_CASE_INSENSITIVE but using only Simple_Case_Folding (scf) mappings,
    * which map each code point to one code point,
    * not full Case_Folding (cf) mappings, which map some code points to multiple code points.
    *
    * This is designed for case-insensitive matches, for example in certain
    * regular expression implementations where only Simple_Case_Folding mappings are used,
    * such as in ECMAScript (JavaScript) regular expressions.
    *
    * @stable ICU 73
    */
   USET_SIMPLE_CASE_INSENSITIVE = 6
};

/**
* Argument values for whether span() and similar functions continue while
* the current character is contained vs. not contained in the set.
*
* The functionality is straightforward for sets with only single code points,
* without strings (which is the common case):
* - USET_SPAN_CONTAINED and USET_SPAN_SIMPLE work the same.
* - USET_SPAN_CONTAINED and USET_SPAN_SIMPLE are inverses of USET_SPAN_NOT_CONTAINED.
* - span() and spanBack() partition any string the same way when
*   alternating between span(USET_SPAN_NOT_CONTAINED) and
*   span(either "contained" condition).
* - Using a complemented (inverted) set and the opposite span conditions
*   yields the same results.
*
* When a set contains multi-code point strings, then these statements may not
* be true, depending on the strings in the set (for example, whether they
* overlap with each other) and the string that is processed.
* For a set with strings:
* - The complement of the set contains the opposite set of code points,
*   but the same set of strings.
*   Therefore, complementing both the set and the span conditions
*   may yield different results.
* - When starting spans at different positions in a string
*   (span(s, ...) vs. span(s+1, ...)) the ends of the spans may be different
*   because a set string may start before the later position.
* - span(USET_SPAN_SIMPLE) may be shorter than
*   span(USET_SPAN_CONTAINED) because it will not recursively try
*   all possible paths.
*   For example, with a set which contains the three strings "xy", "xya" and "ax",
*   span("xyax", USET_SPAN_CONTAINED) will return 4 but
*   span("xyax", USET_SPAN_SIMPLE) will return 3.
*   span(USET_SPAN_SIMPLE) will never be longer than
*   span(USET_SPAN_CONTAINED).
* - With either "contained" condition, span() and spanBack() may partition
*   a string in different ways.
*   For example, with a set which contains the two strings "ab" and "ba",
*   and when processing the string "aba",
*   span() will yield contained/not-contained boundaries of { 0, 2, 3 }
*   while spanBack() will yield boundaries of { 0, 1, 3 }.
*
* Note: If it is important to get the same boundaries whether iterating forward
* or backward through a string, then either only span() should be used and
* the boundaries cached for backward operation, or an ICU BreakIterator
* could be used.
*
* Note: Unpaired surrogates are treated like surrogate code points.
* Similarly, set strings match only on code point boundaries,
* never in the middle of a surrogate pair.
* Illegal UTF-8 sequences are treated like U+FFFD.
* When processing UTF-8 strings, malformed set strings
* (strings with unpaired surrogates which cannot be converted to UTF-8)
* are ignored.
*
* @stable ICU 3.8
*/
typedef enum USetSpanCondition {
   /**
    * Continues a span() while there is no set element at the current position.
    * Increments by one code point at a time.
    * Stops before the first set element (character or string).
    * (For code points only, this is like while contains(current)==false).
    *
    * When span() returns, the substring between where it started and the position
    * it returned consists only of characters that are not in the set,
    * and none of its strings overlap with the span.
    *
    * @stable ICU 3.8
    */
   USET_SPAN_NOT_CONTAINED = 0,
   /**
    * Spans the longest substring that is a concatenation of set elements (characters or strings).
    * (For characters only, this is like while contains(current)==true).
    *
    * When span() returns, the substring between where it started and the position
    * it returned consists only of set elements (characters or strings) that are in the set.
    *
    * If a set contains strings, then the span will be the longest substring for which there
    * exists at least one non-overlapping concatenation of set elements (characters or strings).
    * This is equivalent to a POSIX regular expression for <code>(OR of each set element)*</code>.
    * (Java/ICU/Perl regex stops at the first match of an OR.)
    *
    * @stable ICU 3.8
    */
   USET_SPAN_CONTAINED = 1,
   /**
    * Continues a span() while there is a set element at the current position.
    * Increments by the longest matching element at each position.
    * (For characters only, this is like while contains(current)==true).
    *
    * When span() returns, the substring between where it started and the position
    * it returned consists only of set elements (characters or strings) that are in the set.
    *
    * If a set only contains single characters, then this is the same
    * as USET_SPAN_CONTAINED.
    *
    * If a set contains strings, then the span will be the longest substring
    * with a match at each position with the longest single set element (character or string).
    *
    * Use this span condition together with other longest-match algorithms,
    * such as ICU converters (ucnv_getUnicodeSet()).
    *
    * @stable ICU 3.8
    */
   USET_SPAN_SIMPLE = 2,
#ifndef U_HIDE_DEPRECATED_API
   /**
    * One more than the last span condition.
    * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
    */
   USET_SPAN_CONDITION_COUNT
#endif  // U_HIDE_DEPRECATED_API
} USetSpanCondition;

enum {
   /**
    * Capacity of USerializedSet::staticArray.
    * Enough for any single-code point set.
    * Also provides padding for nice sizeof(USerializedSet).
    * @stable ICU 2.4
    */
   USET_SERIALIZED_STATIC_ARRAY_CAPACITY=8
};

/**
* A serialized form of a Unicode set.  Limited manipulations are
* possible directly on a serialized set.  See below.
* @stable ICU 2.4
*/
typedef struct USerializedSet {
   /**
    * The serialized Unicode Set.
    * @stable ICU 2.4
    */
   const uint16_t *array;
   /**
    * The length of the array that contains BMP characters.
    * @stable ICU 2.4
    */
   int32_t bmpLength;
   /**
    * The total length of the array.
    * @stable ICU 2.4
    */
   int32_t length;
   /**
    * A small buffer for the array to reduce memory allocations.
    * @stable ICU 2.4
    */
   uint16_t staticArray[USET_SERIALIZED_STATIC_ARRAY_CAPACITY];
} USerializedSet;

/*********************************************************************
* USet API
*********************************************************************/

/**
* Create an empty USet object.
* Equivalent to uset_open(1, 0).
* @return a newly created USet.  The caller must call uset_close() on
* it when done.
* @stable ICU 4.2
*/
U_CAPI USet* U_EXPORT2
uset_openEmpty(void);

/**
* Creates a USet object that contains the range of characters
* start..end, inclusive.  If <code>start > end</code> 
* then an empty set is created (same as using uset_openEmpty()).
* @param start first character of the range, inclusive
* @param end last character of the range, inclusive
* @return a newly created USet.  The caller must call uset_close() on
* it when done.
* @stable ICU 2.4
*/
U_CAPI USet* U_EXPORT2
uset_open(UChar32 start, UChar32 end);

/**
* Creates a set from the given pattern.  See the UnicodeSet class
* description for the syntax of the pattern language.
* @param pattern a string specifying what characters are in the set
* @param patternLength the length of the pattern, or -1 if null
* terminated
* @param ec the error code
* @stable ICU 2.4
*/
U_CAPI USet* U_EXPORT2
uset_openPattern(const UChar* pattern, int32_t patternLength,
                UErrorCode* ec);

/**
* Creates a set from the given pattern.  See the UnicodeSet class
* description for the syntax of the pattern language.
* @param pattern a string specifying what characters are in the set
* @param patternLength the length of the pattern, or -1 if null
* terminated
* @param options bitmask for options to apply to the pattern.
* Valid options are USET_IGNORE_SPACE and
* at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
* These case options are mutually exclusive.
* @param ec the error code
* @stable ICU 2.4
*/
U_CAPI USet* U_EXPORT2
uset_openPatternOptions(const UChar* pattern, int32_t patternLength,
                uint32_t options,
                UErrorCode* ec);

/**
* Disposes of the storage used by a USet object.  This function should
* be called exactly once for objects returned by uset_open().
* @param set the object to dispose of
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_close(USet* set);

#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

/**
* \class LocalUSetPointer
* "Smart pointer" class, closes a USet via uset_close().
* For most methods see the LocalPointerBase base class.
*
* @see LocalPointerBase
* @see LocalPointer
* @stable ICU 4.4
*/
U_DEFINE_LOCAL_OPEN_POINTER(LocalUSetPointer, USet, uset_close);

U_NAMESPACE_END

#endif

/**
* Returns a copy of this object.
* If this set is frozen, then the clone will be frozen as well.
* Use uset_cloneAsThawed() for a mutable clone of a frozen set.
* @param set the original set
* @return the newly allocated copy of the set
* @see uset_cloneAsThawed
* @stable ICU 3.8
*/
U_CAPI USet * U_EXPORT2
uset_clone(const USet *set);

/**
* Determines whether the set has been frozen (made immutable) or not.
* See the ICU4J Freezable interface for details.
* @param set the set
* @return true/false for whether the set has been frozen
* @see uset_freeze
* @see uset_cloneAsThawed
* @stable ICU 3.8
*/
U_CAPI UBool U_EXPORT2
uset_isFrozen(const USet *set);

/**
* Freeze the set (make it immutable).
* Once frozen, it cannot be unfrozen and is therefore thread-safe
* until it is deleted.
* See the ICU4J Freezable interface for details.
* Freezing the set may also make some operations faster, for example
* uset_contains() and uset_span().
* A frozen set will not be modified. (It remains frozen.)
* @param set the set
* @return the same set, now frozen
* @see uset_isFrozen
* @see uset_cloneAsThawed
* @stable ICU 3.8
*/
U_CAPI void U_EXPORT2
uset_freeze(USet *set);

/**
* Clone the set and make the clone mutable.
* See the ICU4J Freezable interface for details.
* @param set the set
* @return the mutable clone
* @see uset_freeze
* @see uset_isFrozen
* @see uset_clone
* @stable ICU 3.8
*/
U_CAPI USet * U_EXPORT2
uset_cloneAsThawed(const USet *set);

/**
* Causes the USet object to represent the range <code>start - end</code>.
* If <code>start > end</code> then this USet is set to an empty range.
* A frozen set will not be modified.
* @param set the object to set to the given range
* @param start first character in the set, inclusive
* @param end last character in the set, inclusive
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_set(USet* set,
        UChar32 start, UChar32 end);

/**
* Modifies the set to represent the set specified by the given
* pattern. See the UnicodeSet class description for the syntax of 
* the pattern language. See also the User Guide chapter about UnicodeSet.
* <em>Empties the set passed before applying the pattern.</em>
* A frozen set will not be modified.
* @param set               The set to which the pattern is to be applied. 
* @param pattern           A pointer to UChar string specifying what characters are in the set.
*                          The character at pattern[0] must be a '['.
* @param patternLength     The length of the UChar string. -1 if NUL terminated.
* @param options           A bitmask for options to apply to the pattern.
*                          Valid options are USET_IGNORE_SPACE and
*                          at most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS,
*                          USET_SIMPLE_CASE_INSENSITIVE.
*                          These case options are mutually exclusive.
* @param status            Returns an error if the pattern cannot be parsed.
* @return                  Upon successful parse, the value is either
*                          the index of the character after the closing ']' 
*                          of the parsed pattern.
*                          If the status code indicates failure, then the return value 
*                          is the index of the error in the source.
*
* @stable ICU 2.8
*/
U_CAPI int32_t U_EXPORT2 
uset_applyPattern(USet *set,
                 const UChar *pattern, int32_t patternLength,
                 uint32_t options,
                 UErrorCode *status);

/**
* Modifies the set to contain those code points which have the given value
* for the given binary or enumerated property, as returned by
* u_getIntPropertyValue.  Prior contents of this set are lost.
* A frozen set will not be modified.
*
* @param set the object to contain the code points defined by the property
*
* @param prop a property in the range UCHAR_BIN_START..UCHAR_BIN_LIMIT-1
* or UCHAR_INT_START..UCHAR_INT_LIMIT-1
* or UCHAR_MASK_START..UCHAR_MASK_LIMIT-1.
*
* @param value a value in the range u_getIntPropertyMinValue(prop)..
* u_getIntPropertyMaxValue(prop), with one exception.  If prop is
* UCHAR_GENERAL_CATEGORY_MASK, then value should not be a UCharCategory, but
* rather a mask value produced by U_GET_GC_MASK().  This allows grouped
* categories such as [:L:] to be represented.
*
* @param ec error code input/output parameter
*
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_applyIntPropertyValue(USet* set,
                          UProperty prop, int32_t value, UErrorCode* ec);

/**
* Modifies the set to contain those code points which have the
* given value for the given property.  Prior contents of this
* set are lost.
* A frozen set will not be modified.
*
* @param set the object to contain the code points defined by the given
* property and value alias
*
* @param prop a string specifying a property alias, either short or long.
* The name is matched loosely.  See PropertyAliases.txt for names and a
* description of loose matching.  If the value string is empty, then this
* string is interpreted as either a General_Category value alias, a Script
* value alias, a binary property alias, or a special ID.  Special IDs are
* matched loosely and correspond to the following sets:
*
* "ANY" = [\\u0000-\\U0010FFFF],
* "ASCII" = [\\u0000-\\u007F],
* "Assigned" = [:^Cn:].
*
* @param propLength the length of the prop, or -1 if NULL
*
* @param value a string specifying a value alias, either short or long.
* The name is matched loosely.  See PropertyValueAliases.txt for names
* and a description of loose matching.  In addition to aliases listed,
* numeric values and canonical combining classes may be expressed
* numerically, e.g., ("nv", "0.5") or ("ccc", "220").  The value string
* may also be empty.
*
* @param valueLength the length of the value, or -1 if NULL
*
* @param ec error code input/output parameter
*
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_applyPropertyAlias(USet* set,
                       const UChar *prop, int32_t propLength,
                       const UChar *value, int32_t valueLength,
                       UErrorCode* ec);

/**
* Return true if the given position, in the given pattern, appears
* to be the start of a UnicodeSet pattern.
*
* @param pattern a string specifying the pattern
* @param patternLength the length of the pattern, or -1 if NULL
* @param pos the given position
* @stable ICU 3.2
*/
U_CAPI UBool U_EXPORT2
uset_resemblesPattern(const UChar *pattern, int32_t patternLength,
                     int32_t pos);

/**
* Returns a string representation of this set.  If the result of
* calling this function is passed to a uset_openPattern(), it
* will produce another set that is equal to this one.
* @param set the set
* @param result the string to receive the rules, may be NULL
* @param resultCapacity the capacity of result, may be 0 if result is NULL
* @param escapeUnprintable if true then convert unprintable
* character to their hex escape representations, \\uxxxx or
* \\Uxxxxxxxx.  Unprintable characters are those other than
* U+000A, U+0020..U+007E.
* @param ec error code.
* @return length of string, possibly larger than resultCapacity
* @stable ICU 2.4
*/
U_CAPI int32_t U_EXPORT2
uset_toPattern(const USet* set,
              UChar* result, int32_t resultCapacity,
              UBool escapeUnprintable,
              UErrorCode* ec);

/**
* Adds the given character to the given USet.  After this call,
* uset_contains(set, c) will return true.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param c the character to add
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_add(USet* set, UChar32 c);

/**
* Adds all of the elements in the specified set to this set if
* they're not already present.  This operation effectively
* modifies this set so that its value is the <i>union</i> of the two
* sets.  The behavior of this operation is unspecified if the specified
* collection is modified while the operation is in progress.
* A frozen set will not be modified.
*
* @param set the object to which to add the set
* @param additionalSet the source set whose elements are to be added to this set.
* @stable ICU 2.6
*/
U_CAPI void U_EXPORT2
uset_addAll(USet* set, const USet *additionalSet);

/**
* Adds the given range of characters to the given USet.  After this call,
* uset_contains(set, start, end) will return true.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param start the first character of the range to add, inclusive
* @param end the last character of the range to add, inclusive
* @stable ICU 2.2
*/
U_CAPI void U_EXPORT2
uset_addRange(USet* set, UChar32 start, UChar32 end);

/**
* Adds the given string to the given USet.  After this call,
* uset_containsString(set, str, strLen) will return true.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param str the string to add
* @param strLen the length of the string or -1 if null terminated.
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_addString(USet* set, const UChar* str, int32_t strLen);

/**
* Adds each of the characters in this string to the set. Note: "ch" => {"c", "h"}
* If this set already contains any particular character, it has no effect on that character.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param str the source string
* @param strLen the length of the string or -1 if null terminated.
* @stable ICU 3.4
*/
U_CAPI void U_EXPORT2
uset_addAllCodePoints(USet* set, const UChar *str, int32_t strLen);

/**
* Removes the given character from the given USet.  After this call,
* uset_contains(set, c) will return false.
* A frozen set will not be modified.
* @param set the object from which to remove the character
* @param c the character to remove
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_remove(USet* set, UChar32 c);

/**
* Removes the given range of characters from the given USet.  After this call,
* uset_contains(set, start, end) will return false.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param start the first character of the range to remove, inclusive
* @param end the last character of the range to remove, inclusive
* @stable ICU 2.2
*/
U_CAPI void U_EXPORT2
uset_removeRange(USet* set, UChar32 start, UChar32 end);

/**
* Removes the given string to the given USet.  After this call,
* uset_containsString(set, str, strLen) will return false.
* A frozen set will not be modified.
* @param set the object to which to add the character
* @param str the string to remove
* @param strLen the length of the string or -1 if null terminated.
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_removeString(USet* set, const UChar* str, int32_t strLen);

/**
* Removes EACH of the characters in this string. Note: "ch" == {"c", "h"}
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param str the string
* @param length the length of the string, or -1 if NUL-terminated
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_removeAllCodePoints(USet *set, const UChar *str, int32_t length);

/**
* Removes from this set all of its elements that are contained in the
* specified set.  This operation effectively modifies this
* set so that its value is the <i>asymmetric set difference</i> of
* the two sets.
* A frozen set will not be modified.
* @param set the object from which the elements are to be removed
* @param removeSet the object that defines which elements will be
* removed from this set
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_removeAll(USet* set, const USet* removeSet);

/**
* Retain only the elements in this set that are contained in the
* specified range.  If <code>start > end</code> then an empty range is
* retained, leaving the set empty.  This is equivalent to
* a boolean logic AND, or a set INTERSECTION.
* A frozen set will not be modified.
*
* @param set the object for which to retain only the specified range
* @param start first character, inclusive, of range
* @param end last character, inclusive, of range
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_retain(USet* set, UChar32 start, UChar32 end);

/**
* Retains only the specified string from this set if it is present.
* Upon return this set will be empty if it did not contain s, or
* will only contain s if it did contain s.
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param str the string
* @param length the length of the string, or -1 if NUL-terminated
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_retainString(USet *set, const UChar *str, int32_t length);

/**
* Retains EACH of the characters in this string. Note: "ch" == {"c", "h"}
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param str the string
* @param length the length of the string, or -1 if NUL-terminated
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_retainAllCodePoints(USet *set, const UChar *str, int32_t length);

/**
* Retains only the elements in this set that are contained in the
* specified set.  In other words, removes from this set all of
* its elements that are not contained in the specified set.  This
* operation effectively modifies this set so that its value is
* the <i>intersection</i> of the two sets.
* A frozen set will not be modified.
*
* @param set the object on which to perform the retain
* @param retain set that defines which elements this set will retain
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_retainAll(USet* set, const USet* retain);

/**
* Reallocate this objects internal structures to take up the least
* possible space, without changing this object's value.
* A frozen set will not be modified.
*
* @param set the object on which to perform the compact
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_compact(USet* set);

/**
* This is equivalent to
* <code>uset_complementRange(set, 0, 0x10FFFF)</code>.
*
* <strong>Note:</strong> This performs a symmetric difference with all code points
* <em>and thus retains all multicharacter strings</em>.
* In order to achieve a “code point complement” (all code points minus this set),
* the easiest is to <code>uset_complement(set); uset_removeAllStrings(set);</code>.
*
* A frozen set will not be modified.
* @param set the set
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_complement(USet* set);

/**
* Complements the specified range in this set.  Any character in
* the range will be removed if it is in this set, or will be
* added if it is not in this set.  If <code>start > end</code>
* then an empty range is complemented, leaving the set unchanged.
* This is equivalent to a boolean logic XOR.
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param start first character, inclusive, of range
* @param end last character, inclusive, of range
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_complementRange(USet *set, UChar32 start, UChar32 end);

/**
* Complements the specified string in this set.
* The string will be removed if it is in this set, or will be added if it is not in this set.
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param str the string
* @param length the length of the string, or -1 if NUL-terminated
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_complementString(USet *set, const UChar *str, int32_t length);

/**
* Complements EACH of the characters in this string. Note: "ch" == {"c", "h"}
* A frozen set will not be modified.
*
* @param set the object to be modified
* @param str the string
* @param length the length of the string, or -1 if NUL-terminated
* @stable ICU 69
*/
U_CAPI void U_EXPORT2
uset_complementAllCodePoints(USet *set, const UChar *str, int32_t length);

/**
* Complements in this set all elements contained in the specified
* set.  Any character in the other set will be removed if it is
* in this set, or will be added if it is not in this set.
* A frozen set will not be modified.
*
* @param set the set with which to complement
* @param complement set that defines which elements will be xor'ed
* from this set.
* @stable ICU 3.2
*/
U_CAPI void U_EXPORT2
uset_complementAll(USet* set, const USet* complement);

/**
* Removes all of the elements from this set.  This set will be
* empty after this call returns.
* A frozen set will not be modified.
* @param set the set
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_clear(USet* set);

/**
* Close this set over the given attribute.  For the attribute
* USET_CASE_INSENSITIVE, the result is to modify this set so that:
*
* 1. For each character or string 'a' in this set, all strings or
* characters 'b' such that foldCase(a) == foldCase(b) are added
* to this set.
*
* 2. For each string 'e' in the resulting set, if e !=
* foldCase(e), 'e' will be removed.
*
* Example: [aq\\u00DF{Bc}{bC}{Fi}] => [aAqQ\\u00DF\\uFB01{ss}{bc}{fi}]
*
* (Here foldCase(x) refers to the operation u_strFoldCase, and a
* == b denotes that the contents are the same, not pointer
* comparison.)
*
* A frozen set will not be modified.
*
* @param set the set
*
* @param attributes bitmask for attributes to close over.
* Valid options:
* At most one of USET_CASE_INSENSITIVE, USET_ADD_CASE_MAPPINGS, USET_SIMPLE_CASE_INSENSITIVE.
* These case options are mutually exclusive.
* Unrelated options bits are ignored.
* @stable ICU 4.2
*/
U_CAPI void U_EXPORT2
uset_closeOver(USet* set, int32_t attributes);

/**
* Remove all strings from this set.
*
* @param set the set
* @stable ICU 4.2
*/
U_CAPI void U_EXPORT2
uset_removeAllStrings(USet* set);

/**
* Returns true if the given USet contains no characters and no
* strings.
* @param set the set
* @return true if set is empty
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_isEmpty(const USet* set);

/**
* @param set the set
* @return true if this set contains multi-character strings or the empty string.
* @stable ICU 70
*/
U_CAPI UBool U_EXPORT2
uset_hasStrings(const USet *set);

/**
* Returns true if the given USet contains the given character.
* This function works faster with a frozen set.
* @param set the set
* @param c The codepoint to check for within the set
* @return true if set contains c
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_contains(const USet* set, UChar32 c);

/**
* Returns true if the given USet contains all characters c
* where start <= c && c <= end.
* @param set the set
* @param start the first character of the range to test, inclusive
* @param end the last character of the range to test, inclusive
* @return true if set contains the range
* @stable ICU 2.2
*/
U_CAPI UBool U_EXPORT2
uset_containsRange(const USet* set, UChar32 start, UChar32 end);

/**
* Returns true if the given USet contains the given string.
* @param set the set
* @param str the string
* @param strLen the length of the string or -1 if null terminated.
* @return true if set contains str
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_containsString(const USet* set, const UChar* str, int32_t strLen);

/**
* Returns the index of the given character within this set, where
* the set is ordered by ascending code point.  If the character
* is not in this set, return -1.  The inverse of this method is
* <code>charAt()</code>.
* @param set the set
* @param c the character to obtain the index for
* @return an index from 0..size()-1, or -1
* @stable ICU 3.2
*/
U_CAPI int32_t U_EXPORT2
uset_indexOf(const USet* set, UChar32 c);

/**
* Returns the character at the given index within this set, where
* the set is ordered by ascending code point.  If the index is
* out of range for characters, returns (UChar32)-1.
* The inverse of this method is <code>indexOf()</code>.
*
* For iteration, this is slower than uset_getRangeCount()/uset_getItemCount()
* with uset_getItem(), because for each call it skips linearly over <code>index</code>
* characters in the ranges.
*
* @param set the set
* @param charIndex an index from 0..size()-1 to obtain the char for
* @return the character at the given index, or (UChar32)-1.
* @stable ICU 3.2
*/
U_CAPI UChar32 U_EXPORT2
uset_charAt(const USet* set, int32_t charIndex);

/**
* Returns the number of characters and strings contained in this set.
* The last uset_getStringCount() == (uset_getItemCount() - uset_getRangeCount()) items are strings.
*
* This is slower than uset_getRangeCount() and uset_getItemCount() because
* it counts the code points of all ranges.
*
* @param set the set
* @return a non-negative integer counting the characters and strings
* contained in set
* @stable ICU 2.4
* @see uset_getRangeCount
* @see uset_getStringCount
* @see uset_getItemCount
*/
U_CAPI int32_t U_EXPORT2
uset_size(const USet* set);

/**
* @param set the set
* @return the number of ranges in this set.
* @stable ICU 70
* @see uset_getItemCount
* @see uset_getItem
* @see uset_getStringCount
* @see uset_size
*/
U_CAPI int32_t U_EXPORT2
uset_getRangeCount(const USet *set);

/**
* @param set the set
* @return the number of strings in this set.
* @stable ICU 76
* @see uset_getRangeCount
* @see uset_getItemCount
* @see uset_size
*/
U_CAPI int32_t U_EXPORT2
uset_getStringCount(const USet *set);

/**
* Returns the index-th string (empty or multi-character) in the set.
* The string may not be NUL-terminated.
* The output length must be used, and the caller must not read more than that many UChars.
*
* @param set the set
* @param index the string index, 0 .. uset_getStringCount() - 1
* @param pLength the output string length; must not be NULL
* @return the pointer to the string; NULL if the index is out of range or pLength is NULL
* @stable ICU 76
* @see uset_getStringCount
*/
U_CAPI const UChar* U_EXPORT2
uset_getString(const USet *set, int32_t index, int32_t *pLength);

/**
* Returns the number of items in this set.  An item is either a range
* of characters or a single multicharacter string.
* @param set the set
* @return a non-negative integer counting the character ranges
* and/or strings contained in set
* @stable ICU 2.4
* @see uset_getRangeCount
* @see uset_getStringCount
*/
U_CAPI int32_t U_EXPORT2
uset_getItemCount(const USet* set);

/**
* Returns an item of this set.  An item is either a range of
* characters or a single multicharacter string (which can be the empty string).
*
* If <code>itemIndex</code> is less than uset_getRangeCount(), then this function returns 0,
* and the range is <code>*start</code>..<code>*end</code>.
*
* If <code>itemIndex</code> is at least uset_getRangeCount() and less than uset_getItemCount(), then
* this function copies the string into <code>str[strCapacity]</code> and
* returns the length of the string (0 for the empty string).
* See uset_getString() for a function that does not copy the string contents.
*
* If <code>itemIndex</code> is out of range, then this function returns -1.
*
* Note that 0 is returned for each range as well as for the empty string.
*
* @param set the set
* @param itemIndex a non-negative integer in the range 0..uset_getItemCount(set)-1
* @param start pointer to variable to receive first character in range, inclusive;
*              can be NULL for a string item
* @param end pointer to variable to receive last character in range, inclusive;
*            can be NULL for a string item
* @param str buffer to receive the string, may be NULL
* @param strCapacity capacity of str, or 0 if str is NULL
* @param ec error code; U_INDEX_OUTOFBOUNDS_ERROR if the itemIndex is out of range
* @return the length of the string (0 or >= 2), or 0 if the item is a range,
*         or -1 if the itemIndex is out of range
* @stable ICU 2.4
* @see uset_getString
*/
U_CAPI int32_t U_EXPORT2
uset_getItem(const USet* set, int32_t itemIndex,
            UChar32* start, UChar32* end,
            UChar* str, int32_t strCapacity,
            UErrorCode* ec);

/**
* Returns true if set1 contains all the characters and strings
* of set2. It answers the question, 'Is set1 a superset of set2?'
* @param set1 set to be checked for containment
* @param set2 set to be checked for containment
* @return true if the test condition is met
* @stable ICU 3.2
*/
U_CAPI UBool U_EXPORT2
uset_containsAll(const USet* set1, const USet* set2);

/**
* Returns true if this set contains all the characters
* of the given string. This is does not check containment of grapheme
* clusters, like uset_containsString.
* @param set set of characters to be checked for containment
* @param str string containing codepoints to be checked for containment
* @param strLen the length of the string or -1 if null terminated.
* @return true if the test condition is met
* @stable ICU 3.4
*/
U_CAPI UBool U_EXPORT2
uset_containsAllCodePoints(const USet* set, const UChar *str, int32_t strLen);

/**
* Returns true if set1 contains none of the characters and strings
* of set2. It answers the question, 'Is set1 a disjoint set of set2?'
* @param set1 set to be checked for containment
* @param set2 set to be checked for containment
* @return true if the test condition is met
* @stable ICU 3.2
*/
U_CAPI UBool U_EXPORT2
uset_containsNone(const USet* set1, const USet* set2);

/**
* Returns true if set1 contains some of the characters and strings
* of set2. It answers the question, 'Does set1 and set2 have an intersection?'
* @param set1 set to be checked for containment
* @param set2 set to be checked for containment
* @return true if the test condition is met
* @stable ICU 3.2
*/
U_CAPI UBool U_EXPORT2
uset_containsSome(const USet* set1, const USet* set2);

/**
* Returns the length of the initial substring of the input string which
* consists only of characters and strings that are contained in this set
* (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
* or only of characters and strings that are not contained
* in this set (USET_SPAN_NOT_CONTAINED).
* See USetSpanCondition for details.
* Similar to the strspn() C library function.
* Unpaired surrogates are treated according to contains() of their surrogate code points.
* This function works faster with a frozen set and with a non-negative string length argument.
* @param set the set
* @param s start of the string
* @param length of the string; can be -1 for NUL-terminated
* @param spanCondition specifies the containment condition
* @return the length of the initial substring according to the spanCondition;
*         0 if the start of the string does not fit the spanCondition
* @stable ICU 3.8
* @see USetSpanCondition
*/
U_CAPI int32_t U_EXPORT2
uset_span(const USet *set, const UChar *s, int32_t length, USetSpanCondition spanCondition);

/**
* Returns the start of the trailing substring of the input string which
* consists only of characters and strings that are contained in this set
* (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
* or only of characters and strings that are not contained
* in this set (USET_SPAN_NOT_CONTAINED).
* See USetSpanCondition for details.
* Unpaired surrogates are treated according to contains() of their surrogate code points.
* This function works faster with a frozen set and with a non-negative string length argument.
* @param set the set
* @param s start of the string
* @param length of the string; can be -1 for NUL-terminated
* @param spanCondition specifies the containment condition
* @return the start of the trailing substring according to the spanCondition;
*         the string length if the end of the string does not fit the spanCondition
* @stable ICU 3.8
* @see USetSpanCondition
*/
U_CAPI int32_t U_EXPORT2
uset_spanBack(const USet *set, const UChar *s, int32_t length, USetSpanCondition spanCondition);

/**
* Returns the length of the initial substring of the input string which
* consists only of characters and strings that are contained in this set
* (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
* or only of characters and strings that are not contained
* in this set (USET_SPAN_NOT_CONTAINED).
* See USetSpanCondition for details.
* Similar to the strspn() C library function.
* Malformed byte sequences are treated according to contains(0xfffd).
* This function works faster with a frozen set and with a non-negative string length argument.
* @param set the set
* @param s start of the string (UTF-8)
* @param length of the string; can be -1 for NUL-terminated
* @param spanCondition specifies the containment condition
* @return the length of the initial substring according to the spanCondition;
*         0 if the start of the string does not fit the spanCondition
* @stable ICU 3.8
* @see USetSpanCondition
*/
U_CAPI int32_t U_EXPORT2
uset_spanUTF8(const USet *set, const char *s, int32_t length, USetSpanCondition spanCondition);

/**
* Returns the start of the trailing substring of the input string which
* consists only of characters and strings that are contained in this set
* (USET_SPAN_CONTAINED, USET_SPAN_SIMPLE),
* or only of characters and strings that are not contained
* in this set (USET_SPAN_NOT_CONTAINED).
* See USetSpanCondition for details.
* Malformed byte sequences are treated according to contains(0xfffd).
* This function works faster with a frozen set and with a non-negative string length argument.
* @param set the set
* @param s start of the string (UTF-8)
* @param length of the string; can be -1 for NUL-terminated
* @param spanCondition specifies the containment condition
* @return the start of the trailing substring according to the spanCondition;
*         the string length if the end of the string does not fit the spanCondition
* @stable ICU 3.8
* @see USetSpanCondition
*/
U_CAPI int32_t U_EXPORT2
uset_spanBackUTF8(const USet *set, const char *s, int32_t length, USetSpanCondition spanCondition);

/**
* Returns true if set1 contains all of the characters and strings
* of set2, and vis versa. It answers the question, 'Is set1 equal to set2?'
* @param set1 set to be checked for containment
* @param set2 set to be checked for containment
* @return true if the test condition is met
* @stable ICU 3.2
*/
U_CAPI UBool U_EXPORT2
uset_equals(const USet* set1, const USet* set2);

/*********************************************************************
* Serialized set API
*********************************************************************/

/**
* Serializes this set into an array of 16-bit integers.  Serialization
* (currently) only records the characters in the set; multicharacter
* strings are ignored.
*
* The array
* has following format (each line is one 16-bit integer):
*
*  length     = (n+2*m) | (m!=0?0x8000:0)
*  bmpLength  = n; present if m!=0
*  bmp[0]
*  bmp[1]
*  ...
*  bmp[n-1]
*  supp-high[0]
*  supp-low[0]
*  supp-high[1]
*  supp-low[1]
*  ...
*  supp-high[m-1]
*  supp-low[m-1]
*
* The array starts with a header.  After the header are n bmp
* code points, then m supplementary code points.  Either n or m
* or both may be zero.  n+2*m is always <= 0x7FFF.
*
* If there are no supplementary characters (if m==0) then the
* header is one 16-bit integer, 'length', with value n.
*
* If there are supplementary characters (if m!=0) then the header
* is two 16-bit integers.  The first, 'length', has value
* (n+2*m)|0x8000.  The second, 'bmpLength', has value n.
*
* After the header the code points are stored in ascending order.
* Supplementary code points are stored as most significant 16
* bits followed by least significant 16 bits.
*
* @param set the set
* @param dest pointer to buffer of destCapacity 16-bit integers.
* May be NULL only if destCapacity is zero.
* @param destCapacity size of dest, or zero.  Must not be negative.
* @param pErrorCode pointer to the error code.  Will be set to
* U_INDEX_OUTOFBOUNDS_ERROR if n+2*m > 0x7FFF.  Will be set to
* U_BUFFER_OVERFLOW_ERROR if n+2*m+(m!=0?2:1) > destCapacity.
* @return the total length of the serialized format, including
* the header, that is, n+2*m+(m!=0?2:1), or 0 on error other
* than U_BUFFER_OVERFLOW_ERROR.
* @stable ICU 2.4
*/
U_CAPI int32_t U_EXPORT2
uset_serialize(const USet* set, uint16_t* dest, int32_t destCapacity, UErrorCode* pErrorCode);

/**
* Given a serialized array, fill in the given serialized set object.
* @param fillSet pointer to result
* @param src pointer to start of array
* @param srcLength length of array
* @return true if the given array is valid, otherwise false
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_getSerializedSet(USerializedSet* fillSet, const uint16_t* src, int32_t srcLength);

/**
* Set the USerializedSet to contain the given character (and nothing
* else).
* @param fillSet pointer to result
* @param c The codepoint to set
* @stable ICU 2.4
*/
U_CAPI void U_EXPORT2
uset_setSerializedToOne(USerializedSet* fillSet, UChar32 c);

/**
* Returns true if the given USerializedSet contains the given
* character.
* @param set the serialized set
* @param c The codepoint to check for within the set
* @return true if set contains c
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_serializedContains(const USerializedSet* set, UChar32 c);

/**
* Returns the number of disjoint ranges of characters contained in
* the given serialized set.  Ignores any strings contained in the
* set.
* @param set the serialized set
* @return a non-negative integer counting the character ranges
* contained in set
* @stable ICU 2.4
*/
U_CAPI int32_t U_EXPORT2
uset_getSerializedRangeCount(const USerializedSet* set);

/**
* Returns a range of characters contained in the given serialized
* set.
* @param set the serialized set
* @param rangeIndex a non-negative integer in the range 0..
* uset_getSerializedRangeCount(set)-1
* @param pStart pointer to variable to receive first character
* in range, inclusive
* @param pEnd pointer to variable to receive last character in range,
* inclusive
* @return true if rangeIndex is valid, otherwise false
* @stable ICU 2.4
*/
U_CAPI UBool U_EXPORT2
uset_getSerializedRange(const USerializedSet* set, int32_t rangeIndex,
                       UChar32* pStart, UChar32* pEnd);

#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API

namespace U_HEADER_ONLY_NAMESPACE {

// Note: Not U_COMMON_API, and not a subclass of UMemory, because this is a header-only class,
// not intended to be used via export from the ICU DLL.

/**
* Iterator returned by USetCodePoints.
* @stable ICU 76
*/
class USetCodePointIterator {
public:
   /** @stable ICU 76 */
   USetCodePointIterator(const USetCodePointIterator &other) = default;

   /** @stable ICU 76 */
   bool operator==(const USetCodePointIterator &other) const {
       // No need to compare rangeCount & end given private constructor
       // and assuming we don't compare iterators across the set being modified.
       // And comparing rangeIndex is redundant with comparing c.
       // We might even skip comparing uset.
       // Unless we want operator==() to be "correct" for more than iteration.
       return uset == other.uset && c == other.c;
   }

   /** @stable ICU 76 */
   bool operator!=(const USetCodePointIterator &other) const { return !operator==(other); }

   /** @stable ICU 76 */
   UChar32 operator*() const { return c; }

   /**
    * Pre-increment.
    * @stable ICU 76
    */
   USetCodePointIterator &operator++() {
       if (c < end) {
           ++c;
       } else if (rangeIndex < rangeCount) {
           UErrorCode errorCode = U_ZERO_ERROR;
           int32_t result = uset_getItem(uset, rangeIndex, &c, &end, nullptr, 0, &errorCode);
           if (U_SUCCESS(errorCode) && result == 0) {
               ++rangeIndex;
           } else {
               c = end = U_SENTINEL;
           }
       } else {
           c = end = U_SENTINEL;
       }
       return *this;
   }

   /**
    * Post-increment.
    * @stable ICU 76
    */
   USetCodePointIterator operator++(int) {
       USetCodePointIterator result(*this);
       operator++();
       return result;
   }

private:
   friend class USetCodePoints;

   USetCodePointIterator(const USet *pUset, int32_t nRangeIndex, int32_t nRangeCount)
           : uset(pUset), rangeIndex(nRangeIndex), rangeCount(nRangeCount),
               c(U_SENTINEL), end(U_SENTINEL) {
       // Fetch the first range.
       operator++();
   }

   const USet *uset;
   int32_t rangeIndex;
   int32_t rangeCount;
   UChar32 c, end;
};

/**
* C++ "range" for iterating over the code points of a USet.
*
* \code
* using U_HEADER_NESTED_NAMESPACE::USetCodePoints;
* LocalUSetPointer uset(uset_openPattern(u"[abcçカ🚴]", -1, &errorCode));
* for (UChar32 c : USetCodePoints(uset.getAlias())) {
*     printf("uset.codePoint U+%04lx\n", (long)c);
* }
* \endcode
*
* C++ UnicodeSet has member functions for iteration, including codePoints().
*
* @stable ICU 76
* @see USetRanges
* @see USetStrings
* @see USetElements
*/
class USetCodePoints {
public:
   /**
    * Constructs a C++ "range" object over the code points of the USet.
    * @stable ICU 76
    */
   USetCodePoints(const USet *pUset) : uset(pUset), rangeCount(uset_getRangeCount(pUset)) {}

   /** @stable ICU 76 */
   USetCodePoints(const USetCodePoints &other) = default;

   /** @stable ICU 76 */
   USetCodePointIterator begin() const {
       return USetCodePointIterator(uset, 0, rangeCount);
   }

   /** @stable ICU 76 */
   USetCodePointIterator end() const {
       return USetCodePointIterator(uset, rangeCount, rangeCount);
   }

private:
   const USet *uset;
   int32_t rangeCount;
};

/**
* A contiguous range of code points in a USet/UnicodeSet.
* Returned by USetRangeIterator which is returned by USetRanges.
* Both the rangeStart and rangeEnd are in the range.
* (end() returns an iterator corresponding to rangeEnd+1.)
* @stable ICU 76
*/
struct CodePointRange {
   /** @stable ICU 76 */
   struct iterator {
       /** @stable ICU 76 */
       iterator(UChar32 aC) : c(aC) {}

       /** @stable ICU 76 */
       bool operator==(const iterator &other) const { return c == other.c; }
       /** @stable ICU 76 */
       bool operator!=(const iterator &other) const { return !operator==(other); }

       /** @stable ICU 76 */
       UChar32 operator*() const { return c; }

       /**
        * Pre-increment.
        * @stable ICU 76
        */
       iterator &operator++() {
           ++c;
           return *this;
       }

       /**
        * Post-increment.
        * @stable ICU 76
        */
       iterator operator++(int) {
           return c++;
       }

       /**
        * The current code point in the range.
        * @stable ICU 76
        */
       UChar32 c;
   };

   /** @stable ICU 76 */
   CodePointRange(UChar32 start, UChar32 end) : rangeStart(start), rangeEnd(end) {}
   /** @stable ICU 76 */
   CodePointRange(const CodePointRange &other) = default;
   /** @stable ICU 76 */
   size_t size() const { return (rangeEnd + 1) - rangeStart; }
   /** @stable ICU 76 */
   iterator begin() const { return rangeStart; }
   /** @stable ICU 76 */
   iterator end() const { return rangeEnd + 1; }

   /**
    * Start of a USet/UnicodeSet range of code points.
    * @stable ICU 76
    */
   UChar32 rangeStart;
   /**
    * Inclusive end of a USet/UnicodeSet range of code points.
    * @stable ICU 76
    */
   UChar32 rangeEnd;
};

/**
* Iterator returned by USetRanges.
* @stable ICU 76
*/
class USetRangeIterator {
public:
   /** @stable ICU 76 */
   USetRangeIterator(const USetRangeIterator &other) = default;

   /** @stable ICU 76 */
   bool operator==(const USetRangeIterator &other) const {
       // No need to compare rangeCount given private constructor
       // and assuming we don't compare iterators across the set being modified.
       // We might even skip comparing uset.
       // Unless we want operator==() to be "correct" for more than iteration.
       return uset == other.uset && rangeIndex == other.rangeIndex;
   }

   /** @stable ICU 76 */
   bool operator!=(const USetRangeIterator &other) const { return !operator==(other); }

   /** @stable ICU 76 */
   CodePointRange operator*() const {
       if (rangeIndex < rangeCount) {
           UChar32 start, end;
           UErrorCode errorCode = U_ZERO_ERROR;
           int32_t result = uset_getItem(uset, rangeIndex, &start, &end, nullptr, 0, &errorCode);
           if (U_SUCCESS(errorCode) && result == 0) {
               return CodePointRange(start, end);
           }
       }
       return CodePointRange(U_SENTINEL, U_SENTINEL);
   }

   /**
    * Pre-increment.
    * @stable ICU 76
    */
   USetRangeIterator &operator++() {
       ++rangeIndex;
       return *this;
   }

   /**
    * Post-increment.
    * @stable ICU 76
    */
   USetRangeIterator operator++(int) {
       USetRangeIterator result(*this);
       ++rangeIndex;
       return result;
   }

private:
   friend class USetRanges;

   USetRangeIterator(const USet *pUset, int32_t nRangeIndex, int32_t nRangeCount)
           : uset(pUset), rangeIndex(nRangeIndex), rangeCount(nRangeCount) {}

   const USet *uset;
   int32_t rangeIndex;
   int32_t rangeCount;
};

/**
* C++ "range" for iterating over the code point ranges of a USet.
*
* \code
* using U_HEADER_NESTED_NAMESPACE::USetRanges;
* LocalUSetPointer uset(uset_openPattern(u"[abcçカ🚴]", -1, &errorCode));
* for (auto [start, end] : USetRanges(uset.getAlias())) {
*     printf("uset.range U+%04lx..U+%04lx\n", (long)start, (long)end);
* }
* for (auto range : USetRanges(uset.getAlias())) {
*     for (UChar32 c : range) {
*         printf("uset.range.c U+%04lx\n", (long)c);
*     }
* }
* \endcode
*
* C++ UnicodeSet has member functions for iteration, including ranges().
*
* @stable ICU 76
* @see USetCodePoints
* @see USetStrings
* @see USetElements
*/
class USetRanges {
public:
   /**
    * Constructs a C++ "range" object over the code point ranges of the USet.
    * @stable ICU 76
    */
   USetRanges(const USet *pUset) : uset(pUset), rangeCount(uset_getRangeCount(pUset)) {}

   /** @stable ICU 76 */
   USetRanges(const USetRanges &other) = default;

   /** @stable ICU 76 */
   USetRangeIterator begin() const {
       return USetRangeIterator(uset, 0, rangeCount);
   }

   /** @stable ICU 76 */
   USetRangeIterator end() const {
       return USetRangeIterator(uset, rangeCount, rangeCount);
   }

private:
   const USet *uset;
   int32_t rangeCount;
};

/**
* Iterator returned by USetStrings.
* @stable ICU 76
*/
class USetStringIterator {
public:
   /** @stable ICU 76 */
   USetStringIterator(const USetStringIterator &other) = default;

   /** @stable ICU 76 */
   bool operator==(const USetStringIterator &other) const {
       // No need to compare count given private constructor
       // and assuming we don't compare iterators across the set being modified.
       // We might even skip comparing uset.
       // Unless we want operator==() to be "correct" for more than iteration.
       return uset == other.uset && index == other.index;
   }

   /** @stable ICU 76 */
   bool operator!=(const USetStringIterator &other) const { return !operator==(other); }

   /** @stable ICU 76 */
   std::u16string_view operator*() const {
       if (index < count) {
           int32_t length;
           const UChar *uchars = uset_getString(uset, index, &length);
           // assert uchars != nullptr;
           return {uprv_char16PtrFromUChar(uchars), static_cast<size_t>(length)};
       }
       return {};
   }

   /**
    * Pre-increment.
    * @stable ICU 76
    */
   USetStringIterator &operator++() {
       ++index;
       return *this;
   }

   /**
    * Post-increment.
    * @stable ICU 76
    */
   USetStringIterator operator++(int) {
       USetStringIterator result(*this);
       ++index;
       return result;
   }

private:
   friend class USetStrings;

   USetStringIterator(const USet *pUset, int32_t nIndex, int32_t nCount)
           : uset(pUset), index(nIndex), count(nCount) {}

   const USet *uset;
   int32_t index;
   int32_t count;
};

/**
* C++ "range" for iterating over the empty and multi-character strings of a USet.
*
* \code
* using U_HEADER_NESTED_NAMESPACE::USetStrings;
* LocalUSetPointer uset(uset_openPattern(u"[abcçカ🚴{}{abc}{de}]", -1, &errorCode));
* for (auto s : USetStrings(uset.getAlias())) {
*     int32_t len32 = s.length();
*     char utf8[200];
*     u_strToUTF8WithSub(utf8, int32_t{sizeof(utf8) - 1}, nullptr,
*                        s.data(), len32, 0xFFFD, nullptr, errorCode);
*     printf("uset.string length %ld \"%s\"\n", long{len32}, utf8);
* }
* \endcode
*
* C++ UnicodeSet has member functions for iteration, including strings().
*
* @stable ICU 76
* @see USetCodePoints
* @see USetRanges
* @see USetElements
*/
class USetStrings {
public:
   /**
    * Constructs a C++ "range" object over the strings of the USet.
    * @stable ICU 76
    */
   USetStrings(const USet *pUset) : uset(pUset), count(uset_getStringCount(pUset)) {}

   /** @stable ICU 76 */
   USetStrings(const USetStrings &other) = default;

   /** @stable ICU 76 */
   USetStringIterator begin() const {
       return USetStringIterator(uset, 0, count);
   }

   /** @stable ICU 76 */
   USetStringIterator end() const {
       return USetStringIterator(uset, count, count);
   }

private:
   const USet *uset;
   int32_t count;
};

#ifndef U_HIDE_DRAFT_API
/**
* Iterator returned by USetElements.
* @draft ICU 77
*/
class USetElementIterator {
public:
   /** @draft ICU 77 */
   USetElementIterator(const USetElementIterator &other) = default;

   /** @draft ICU 77 */
   bool operator==(const USetElementIterator &other) const {
       // No need to compare rangeCount & end given private constructor
       // and assuming we don't compare iterators across the set being modified.
       // We might even skip comparing uset.
       // Unless we want operator==() to be "correct" for more than iteration.
       return uset == other.uset && c == other.c && index == other.index;
   }

   /** @draft ICU 77 */
   bool operator!=(const USetElementIterator &other) const { return !operator==(other); }

   /** @draft ICU 77 */
   std::u16string operator*() const {
       if (c >= 0) {
           return c <= 0xffff ?
               std::u16string({static_cast<char16_t>(c)}) :
               std::u16string({U16_LEAD(c), U16_TRAIL(c)});
       } else if (index < totalCount) {
           int32_t length;
           const UChar *uchars = uset_getString(uset, index - rangeCount, &length);
           // assert uchars != nullptr;
           return {uprv_char16PtrFromUChar(uchars), static_cast<size_t>(length)};
       } else {
           return {};
       }
   }

   /**
    * Pre-increment.
    * @draft ICU 77
    */
   USetElementIterator &operator++() {
       if (c < end) {
           ++c;
       } else if (index < rangeCount) {
           UErrorCode errorCode = U_ZERO_ERROR;
           int32_t result = uset_getItem(uset, index, &c, &end, nullptr, 0, &errorCode);
           if (U_SUCCESS(errorCode) && result == 0) {
               ++index;
           } else {
               c = end = U_SENTINEL;
           }
       } else if (c >= 0) {
           // assert index == rangeCount;
           // Switch from the last range to the first string.
           c = end = U_SENTINEL;
       } else {
           ++index;
       }
       return *this;
   }

   /**
    * Post-increment.
    * @draft ICU 77
    */
   USetElementIterator operator++(int) {
       USetElementIterator result(*this);
       operator++();
       return result;
   }

private:
   friend class USetElements;

   USetElementIterator(const USet *pUset, int32_t nIndex, int32_t nRangeCount, int32_t nTotalCount)
           : uset(pUset), index(nIndex), rangeCount(nRangeCount), totalCount(nTotalCount),
               c(U_SENTINEL), end(U_SENTINEL) {
       if (index < rangeCount) {
           // Fetch the first range.
           operator++();
       }
       // Otherwise don't move beyond the (index - rangeCount)-th string.
   }

   const USet *uset;
   int32_t index;
   /** Number of UnicodeSet/USet code point ranges. */
   int32_t rangeCount;
   /**
    * Number of code point ranges plus number of strings.
    * index starts from 0, counts ranges while less than rangeCount,
    * then counts strings while at least rangeCount and less than totalCount.
    *
    * Note that totalCount is the same as uset_getItemCount(), but usually
    * smaller than the number of elements returned by this iterator
    * because we return each code point of each range.
    */
   int32_t totalCount;
   UChar32 c, end;
};

/**
* A C++ "range" for iterating over all of the elements of a USet.
* Convenient all-in one iteration, but creates a std::u16string for each
* code point or string.
*
* Code points are returned first, then empty and multi-character strings.
*
* \code
* using U_HEADER_NESTED_NAMESPACE::USetElements;
* LocalUSetPointer uset(uset_openPattern(u"[abcçカ🚴{}{abc}{de}]", -1, &errorCode));
* for (auto el : USetElements(uset.getAlias())) {
*     int32_t len32 = el.length();
*     char utf8[200];
*     u_strToUTF8WithSub(utf8, int32_t{sizeof(utf8) - 1}, nullptr,
*                        el.data(), len32, 0xFFFD, nullptr, errorCode);
*     printf("uset.element length %ld \"%s\"\n", long{len32}, utf8);
* }
* \endcode
*
* C++ UnicodeSet has member functions for iteration, including begin() and end().
*
* @return an all-elements iterator.
* @draft ICU 77
* @see USetCodePoints
* @see USetRanges
* @see USetStrings
*/
class USetElements {
public:
   /**
    * Constructs a C++ "range" object over all of the elements of the USet.
    * @draft ICU 77
    */
   USetElements(const USet *pUset)
       : uset(pUset), rangeCount(uset_getRangeCount(pUset)),
           stringCount(uset_getStringCount(pUset)) {}

   /** @draft ICU 77 */
   USetElements(const USetElements &other) = default;

   /** @draft ICU 77 */
   USetElementIterator begin() const {
       return USetElementIterator(uset, 0, rangeCount, rangeCount + stringCount);
   }

   /** @draft ICU 77 */
   USetElementIterator end() const {
       return USetElementIterator(uset, rangeCount + stringCount, rangeCount, rangeCount + stringCount);
   }

private:
   const USet *uset;
   int32_t rangeCount, stringCount;
};

#endif  // U_HIDE_DRAFT_API

}  // namespace U_HEADER_ONLY_NAMESPACE

#endif  // U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API

#endif  // __USET_H__