220 lines
8.1 KiB
C++
220 lines
8.1 KiB
C++
/*
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**************************************************************************
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* Copyright (C) 1999-2001, International Business Machines Corporation and
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* others. All Rights Reserved.
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**************************************************************************
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* Date Name Description
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* 11/17/99 aliu Creation. Ported from java. Modified to
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* match current UnicodeString API. Forced
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* to use name "handleReplaceBetween" because
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* of existing methods in UnicodeString.
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**************************************************************************
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*/
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#ifndef REP_H
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#define REP_H
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#include "unicode/utypes.h"
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U_NAMESPACE_BEGIN
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class UnicodeString;
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/**
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* <code>Replaceable</code> is an abstract base class representing a
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* string of characters that supports the replacement of a range of
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* itself with a new string of characters. It is used by APIs that
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* change a piece of text while retaining style attributes. In other
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* words, an implicit aspect of the <code>Replaceable</code> API is
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* that during a replace operation, new characters take on the
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* attributes, if any, of the old characters. For example, if the
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* string "the <b>bold</b> font" has range (4, 8) replaced with
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* "strong", then it becomes "the <b>strong</b> font".
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*
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* <p><code>Replaceable</code> specifies ranges using an initial
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* offset and a limit offset. The range of characters thus specified
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* includes the characters at offset initial..limit-1. That is, the
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* start offset is inclusive, and the limit offset is exclusive.
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*
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* <p><code>Replaceable</code> also includes API to access characters
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* in the string: <code>length()</code>, <code>charAt()</code>, and
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* <code>extractBetween()</code>.
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*
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* <p>If a subclass supports styles, then typically the behavior is the following:
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* <ul>
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* <li>Set the styles to the style of the first character replaced</li>
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* <li>If no characters are replaced, use the style of the previous
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* character</li>
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* <li>If there is no previous character (i.e. start == 0), use the following
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* character</li>
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* <li>If there is no following character (i.e. the replaceable was empty), a
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* default style.<br>
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* </li>
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* </ul>
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* If this is not the behavior, the subclass should document any differences.
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* @author Alan Liu
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* @stable
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*/
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class U_COMMON_API Replaceable {
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public:
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/**
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* Destructor.
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* @stable
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*/
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virtual ~Replaceable();
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/**
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* Return the number of characters in the text.
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* @return number of characters in text
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* @draft ICU 1.8
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*/
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inline int32_t length() const;
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/**
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* Return the Unicode code unit at the given offset into the text.
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* @param offset an integer between 0 and <code>length()</code>-1
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* inclusive
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* @return code unit of text at given offset
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* @draft ICU 1.8
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*/
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inline UChar charAt(UTextOffset offset) const;
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/**
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* Return the Unicode code point that contains the code unit
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* at the given offset into the text.
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* @param offset an integer between 0 and <code>length()</code>-1
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* inclusive that indicates the text offset of any of the code units
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* that will be assembled into a code point (21-bit value) and returned
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* @return code point of text at given offset
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* @draft ICU 1.8
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*/
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inline UChar32 char32At(UTextOffset offset) const;
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/**
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* Copy characters from this object into the destination character
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* array. The first character to be copied is at index
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* <code>srcStart</code>; the last character to be copied is at
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* index <code>srcLimit-1</code> (thus the total number of
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* characters to be copied is <code>srcLimit-srcStart</code>). The
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* characters are copied into the subarray of <code>dst</code>
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* starting at index <code>dstStart</code> and ending at index
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* <code>dstStart + (srcLimit-srcStart) - 1</code>.
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*
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* @param srcStart the beginning index to copy, inclusive; <code>0
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* <= srcStart <= srcLimit</code>.
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* @param srcLimit the ending index to copy, exclusive;
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* <code>srcStart <= srcLimit <= length()</code>.
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* @param dst the destination array.
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* @param dstStart the start offset in the destination array.
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* @draft
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*/
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/* THIS API IS NOT NEEDED, BUT KEPT HERE AS A COMMENT IN
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CASE OF FUTURE NEED. CURRENTLY INDIVIDUAL CHARACTER
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ACCESS SUFFICES. */
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/* virtual void extractBetween(UTextOffset srcStart,
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UTextOffset srcLimit,
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UChar* dst,
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UTextOffset dstStart = 0) const = 0; */
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/**
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* Replace a substring of this object with the given text. If the
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* characters being replaced have attributes, the new characters
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* that replace them should be given the same attributes.
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*
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* <p>Subclasses must ensure that if the text between start and
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* limit is equal to the replacement text, that replace has no
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* effect. That is, any out-of-band information such as styles
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* should be unaffected. In addition, subclasses are encourage to
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* check for initial and trailing identical characters, and make a
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* smaller replacement if possible. This will preserve as much
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* style information as possible.
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= length()</code>.
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* @param text the text to replace characters <code>start</code>
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* to <code>limit - 1</code>
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* @stable
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*/
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virtual void handleReplaceBetween(UTextOffset start,
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UTextOffset limit,
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const UnicodeString& text) = 0;
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// Note: All other methods in this class take the names of
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// existing UnicodeString methods. This method is the exception.
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// It is named differently because all replace methods of
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// UnicodeString return a UnicodeString&. The 'between' is
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// required in order to conform to the UnicodeString naming
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// convention; API taking start/length are named <operation>, and
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// those taking start/limit are named <operationBetween>. The
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// 'handle' is added because 'replaceBetween' and
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// 'doReplaceBetween' are already taken.
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/**
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* Copy a substring of this object, retaining attribute (out-of-band)
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* information. This method is used to duplicate or reorder substrings.
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* The destination index must not overlap the source range.
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* Implementations that do not care about maintaining out-of-band
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* information or performance during copying may use the naive
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* implementation:
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*
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* <pre> char[] text = new char[limit - start];
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* getChars(start, limit, text, 0);
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* replace(dest, dest, text, 0, limit - start);</pre>
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*
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* @param start the beginning index, inclusive; <code>0 <= start <=
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* limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit <=
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* length()</code>.
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* @param dest the destination index. The characters from
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* <code>start..limit-1</code> will be copied to <code>dest</code>.
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* Implementations of this method may assume that <code>dest <= start ||
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* dest >= limit</code>.
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* @stable */
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virtual void copy(int32_t start, int32_t limit, int32_t dest) = 0;
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protected:
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/**
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* Default constructor.
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*/
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Replaceable();
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/**
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* Virtual version of length().
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*/
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virtual int32_t getLength() const = 0;
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/**
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* Virtual version of charAt().
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*/
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virtual UChar getCharAt(UTextOffset offset) const = 0;
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/**
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* Virtual version of char32At().
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*/
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virtual UChar32 getChar32At(UTextOffset offset) const = 0;
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};
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inline Replaceable::Replaceable() {}
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inline Replaceable::~Replaceable() {}
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inline int32_t
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Replaceable::length() const {
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return getLength();
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}
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inline UChar
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Replaceable::charAt(UTextOffset offset) const {
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return getCharAt(offset);
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}
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inline UChar32
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Replaceable::char32At(UTextOffset offset) const {
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return getChar32At(offset);
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}
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U_NAMESPACE_END
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#endif
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