324 lines
9.6 KiB
C++
324 lines
9.6 KiB
C++
// © 2016 and later: Unicode, Inc. and others.
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// License & terms of use: http://www.unicode.org/copyright.html
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/*
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**********************************************************************
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* Copyright (c) 2002-2014, International Business Machines
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* Corporation and others. All Rights Reserved.
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**********************************************************************
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*/
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#ifndef USETITER_H
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#define USETITER_H
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#include "unicode/utypes.h"
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#if U_SHOW_CPLUSPLUS_API
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#include "unicode/uobject.h"
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#include "unicode/unistr.h"
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/**
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* \file
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* \brief C++ API: UnicodeSetIterator iterates over the contents of a UnicodeSet.
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*/
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U_NAMESPACE_BEGIN
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class UnicodeSet;
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class UnicodeString;
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/**
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*
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* UnicodeSetIterator iterates over the contents of a UnicodeSet. It
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* iterates over either code points or code point ranges. After all
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* code points or ranges have been returned, it returns the
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* multicharacter strings of the UnicodeSet, if any.
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*
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* This class is not intended for public subclassing.
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*
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* <p>To iterate over code points and strings, use a loop like this:
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* <pre>
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* UnicodeSetIterator it(set);
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* while (it.next()) {
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* processItem(it.getString());
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* }
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* </pre>
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* <p>Each item in the set is accessed as a string. Set elements
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* consisting of single code points are returned as strings containing
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* just the one code point.
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*
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* <p>To iterate over code point ranges, instead of individual code points,
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* use a loop like this:
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* <pre>
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* UnicodeSetIterator it(set);
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* while (it.nextRange()) {
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* if (it.isString()) {
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* processString(it.getString());
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* } else {
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* processCodepointRange(it.getCodepoint(), it.getCodepointEnd());
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* }
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* }
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* </pre>
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*
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* To iterate over only the strings, start with <code>skipToStrings()</code>.
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*
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* @author M. Davis
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* @stable ICU 2.4
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*/
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class U_COMMON_API UnicodeSetIterator U_FINAL : public UObject {
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/**
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* Value of <tt>codepoint</tt> if the iterator points to a string.
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* If <tt>codepoint == IS_STRING</tt>, then examine
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* <tt>string</tt> for the current iteration result.
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*/
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enum { IS_STRING = -1 };
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/**
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* Current code point, or the special value <tt>IS_STRING</tt>, if
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* the iterator points to a string.
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*/
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UChar32 codepoint;
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/**
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* When iterating over ranges using <tt>nextRange()</tt>,
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* <tt>codepointEnd</tt> contains the inclusive end of the
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* iteration range, if <tt>codepoint != IS_STRING</tt>. If
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* iterating over code points using <tt>next()</tt>, or if
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* <tt>codepoint == IS_STRING</tt>, then the value of
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* <tt>codepointEnd</tt> is undefined.
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*/
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UChar32 codepointEnd;
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/**
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* If <tt>codepoint == IS_STRING</tt>, then <tt>string</tt> points
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* to the current string. If <tt>codepoint != IS_STRING</tt>, the
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* value of <tt>string</tt> is undefined.
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*/
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const UnicodeString* string;
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public:
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/**
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* Create an iterator over the given set. The iterator is valid
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* only so long as <tt>set</tt> is valid.
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* @param set set to iterate over
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* @stable ICU 2.4
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*/
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UnicodeSetIterator(const UnicodeSet& set);
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/**
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* Create an iterator over nothing. <tt>next()</tt> and
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* <tt>nextRange()</tt> return false. This is a convenience
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* constructor allowing the target to be set later.
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* @stable ICU 2.4
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*/
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UnicodeSetIterator();
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/**
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* Destructor.
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* @stable ICU 2.4
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*/
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virtual ~UnicodeSetIterator();
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/**
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* Returns true if the current element is a string. If so, the
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* caller can retrieve it with <tt>getString()</tt>. If this
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* method returns false, the current element is a code point or
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* code point range, depending on whether <tt>next()</tt> or
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* <tt>nextRange()</tt> was called.
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* Elements of types string and codepoint can both be retrieved
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* with the function <tt>getString()</tt>.
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* Elements of type codepoint can also be retrieved with
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* <tt>getCodepoint()</tt>.
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* For ranges, <tt>getCodepoint()</tt> returns the starting codepoint
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* of the range, and <tt>getCodepointEnd()</tt> returns the end
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* of the range.
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* @stable ICU 2.4
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*/
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inline UBool isString() const;
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/**
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* Returns the current code point, if <tt>isString()</tt> returned
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* false. Otherwise returns an undefined result.
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* @stable ICU 2.4
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*/
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inline UChar32 getCodepoint() const;
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/**
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* Returns the end of the current code point range, if
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* <tt>isString()</tt> returned false and <tt>nextRange()</tt> was
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* called. Otherwise returns an undefined result.
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* @stable ICU 2.4
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*/
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inline UChar32 getCodepointEnd() const;
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/**
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* Returns the current string, if <tt>isString()</tt> returned
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* true. If the current iteration item is a code point, a UnicodeString
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* containing that single code point is returned.
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*
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* Ownership of the returned string remains with the iterator.
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* The string is guaranteed to remain valid only until the iterator is
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* advanced to the next item, or until the iterator is deleted.
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*
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* @stable ICU 2.4
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*/
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const UnicodeString& getString();
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/**
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* Skips over the remaining code points/ranges, if any.
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* A following call to next() or nextRange() will yield a string, if there is one.
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* No-op if next() would return false, or if it would yield a string anyway.
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*
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* @return *this
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* @stable ICU 70
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* @see UnicodeSet#strings()
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*/
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inline UnicodeSetIterator &skipToStrings() {
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// Finish code point/range iteration.
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range = endRange;
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endElement = -1;
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nextElement = 0;
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return *this;
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}
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/**
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* Advances the iteration position to the next element in the set,
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* which can be either a single code point or a string.
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* If there are no more elements in the set, return false.
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*
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* <p>
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* If <tt>isString() == true</tt>, the value is a
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* string, otherwise the value is a
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* single code point. Elements of either type can be retrieved
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* with the function <tt>getString()</tt>, while elements of
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* consisting of a single code point can be retrieved with
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* <tt>getCodepoint()</tt>
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*
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* <p>The order of iteration is all code points in sorted order,
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* followed by all strings sorted order. Do not mix
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* calls to <tt>next()</tt> and <tt>nextRange()</tt> without
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* calling <tt>reset()</tt> between them. The results of doing so
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* are undefined.
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*
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* @return true if there was another element in the set.
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* @stable ICU 2.4
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*/
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UBool next();
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/**
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* Returns the next element in the set, either a code point range
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* or a string. If there are no more elements in the set, return
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* false. If <tt>isString() == true</tt>, the value is a
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* string and can be accessed with <tt>getString()</tt>. Otherwise the value is a
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* range of one or more code points from <tt>getCodepoint()</tt> to
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* <tt>getCodepointeEnd()</tt> inclusive.
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*
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* <p>The order of iteration is all code points ranges in sorted
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* order, followed by all strings sorted order. Ranges are
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* disjoint and non-contiguous. The value returned from <tt>getString()</tt>
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* is undefined unless <tt>isString() == true</tt>. Do not mix calls to
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* <tt>next()</tt> and <tt>nextRange()</tt> without calling
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* <tt>reset()</tt> between them. The results of doing so are
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* undefined.
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*
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* @return true if there was another element in the set.
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* @stable ICU 2.4
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*/
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UBool nextRange();
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/**
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* Sets this iterator to visit the elements of the given set and
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* resets it to the start of that set. The iterator is valid only
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* so long as <tt>set</tt> is valid.
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* @param set the set to iterate over.
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* @stable ICU 2.4
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*/
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void reset(const UnicodeSet& set);
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/**
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* Resets this iterator to the start of the set.
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* @stable ICU 2.4
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*/
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void reset();
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/**
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* ICU "poor man's RTTI", returns a UClassID for this class.
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*
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* @stable ICU 2.4
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*/
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static UClassID U_EXPORT2 getStaticClassID();
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/**
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* ICU "poor man's RTTI", returns a UClassID for the actual class.
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*
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* @stable ICU 2.4
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*/
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virtual UClassID getDynamicClassID() const override;
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// ======================= PRIVATES ===========================
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private:
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// endElement and nextElements are really UChar32's, but we keep
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// them as signed int32_t's so we can do comparisons with
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// endElement set to -1. Leave them as int32_t's.
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/** The set
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*/
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const UnicodeSet* set;
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/** End range
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*/
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int32_t endRange;
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/** Range
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*/
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int32_t range;
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/** End element
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*/
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int32_t endElement;
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/** Next element
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*/
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int32_t nextElement;
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/** Next string
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*/
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int32_t nextString;
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/** String count
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*/
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int32_t stringCount;
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/**
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* Points to the string to use when the caller asks for a
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* string and the current iteration item is a code point, not a string.
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*/
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UnicodeString *cpString;
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/** Copy constructor. Disallowed.
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*/
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UnicodeSetIterator(const UnicodeSetIterator&) = delete;
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/** Assignment operator. Disallowed.
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*/
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UnicodeSetIterator& operator=(const UnicodeSetIterator&) = delete;
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/** Load range
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*/
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void loadRange(int32_t range);
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};
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inline UBool UnicodeSetIterator::isString() const {
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return codepoint < 0;
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}
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inline UChar32 UnicodeSetIterator::getCodepoint() const {
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return codepoint;
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}
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inline UChar32 UnicodeSetIterator::getCodepointEnd() const {
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return codepointEnd;
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}
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U_NAMESPACE_END
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#endif /* U_SHOW_CPLUSPLUS_API */
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#endif
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