scuffed-code/icu4c/source/common/unicode/rep.h

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/*
**************************************************************************
* Copyright (C) 1999-2001, International Business Machines Corporation and
* others. All Rights Reserved.
**************************************************************************
* Date Name Description
* 11/17/99 aliu Creation. Ported from java. Modified to
* match current UnicodeString API. Forced
* to use name "handleReplaceBetween" because
* of existing methods in UnicodeString.
**************************************************************************
*/
#ifndef REP_H
#define REP_H
#include "unicode/utypes.h"
U_NAMESPACE_BEGIN
class UnicodeString;
/**
* <code>Replaceable</code> is an abstract base class representing a
* string of characters that supports the replacement of a range of
* itself with a new string of characters. It is used by APIs that
* change a piece of text while retaining style attributes. In other
* words, an implicit aspect of the <code>Replaceable</code> API is
* that during a replace operation, new characters take on the
* attributes, if any, of the old characters. For example, if the
* string "the <b>bold</b> font" has range (4, 8) replaced with
* "strong", then it becomes "the <b>strong</b> font".
*
* <p><code>Replaceable</code> specifies ranges using an initial
* offset and a limit offset. The range of characters thus specified
* includes the characters at offset initial..limit-1. That is, the
* start offset is inclusive, and the limit offset is exclusive.
*
* <p><code>Replaceable</code> also includes API to access characters
* in the string: <code>length()</code>, <code>charAt()</code>, and
* <code>extractBetween()</code>.
*
* <p>If a subclass supports styles, then typically the behavior is the following:
* <ul>
* <li>Set the styles to the style of the first character replaced</li>
* <li>If no characters are replaced, use the style of the previous
* character</li>
* <li>If there is no previous character (i.e. start == 0), use the following
* character</li>
* <li>If there is no following character (i.e. the replaceable was empty), a
* default style.<br>
* </li>
* </ul>
* If this is not the behavior, the subclass should document any differences.
* @author Alan Liu
* @stable
*/
class U_COMMON_API Replaceable {
public:
/**
* Destructor.
* @stable
*/
virtual ~Replaceable();
/**
* Return the number of characters in the text.
* @return number of characters in text
* @draft ICU 1.8
*/
inline int32_t length() const;
/**
* Return the Unicode code unit at the given offset into the text.
* @param offset an integer between 0 and <code>length()</code>-1
* inclusive
* @return code unit of text at given offset
* @draft ICU 1.8
*/
inline UChar charAt(int32_t offset) const;
/**
* Return the Unicode code point that contains the code unit
* at the given offset into the text.
* @param offset an integer between 0 and <code>length()</code>-1
* inclusive that indicates the text offset of any of the code units
* that will be assembled into a code point (21-bit value) and returned
* @return code point of text at given offset
* @draft ICU 1.8
*/
inline UChar32 char32At(int32_t offset) const;
/**
* Copy the characters in the range [<tt>start</tt>, <tt>limit</tt>)
* into the UnicodeString <tt>target</tt>.
* @param start offset of first character which will be copied
* @param limit offset immediately following the last character to
* be copied
* @param target UnicodeString into which to copy characters.
* @return A reference to <TT>target</TT>
* @draft ICU 2.1
*/
virtual void extractBetween(int32_t start,
int32_t limit,
UnicodeString& target) const = 0;
/**
* Replace a substring of this object with the given text. If the
* characters being replaced have attributes, the new characters
* that replace them should be given the same attributes.
*
* <p>Subclasses must ensure that if the text between start and
* limit is equal to the replacement text, that replace has no
* effect. That is, any out-of-band information such as styles
* should be unaffected. In addition, subclasses are encourage to
* check for initial and trailing identical characters, and make a
* smaller replacement if possible. This will preserve as much
* style information as possible.
* @param start the beginning index, inclusive; <code>0 <= start
* <= limit</code>.
* @param limit the ending index, exclusive; <code>start <= limit
* <= length()</code>.
* @param text the text to replace characters <code>start</code>
* to <code>limit - 1</code>
* @stable
*/
virtual void handleReplaceBetween(int32_t start,
int32_t limit,
const UnicodeString& text) = 0;
// Note: All other methods in this class take the names of
// existing UnicodeString methods. This method is the exception.
// It is named differently because all replace methods of
// UnicodeString return a UnicodeString&. The 'between' is
// required in order to conform to the UnicodeString naming
// convention; API taking start/length are named <operation>, and
// those taking start/limit are named <operationBetween>. The
// 'handle' is added because 'replaceBetween' and
// 'doReplaceBetween' are already taken.
/**
* Copy a substring of this object, retaining attribute (out-of-band)
* information. This method is used to duplicate or reorder substrings.
* The destination index must not overlap the source range.
* Implementations that do not care about maintaining out-of-band
* information or performance during copying may use the naive
* implementation:
*
* <pre> char[] text = new char[limit - start];
* getChars(start, limit, text, 0);
* replace(dest, dest, text, 0, limit - start);</pre>
*
* @param start the beginning index, inclusive; <code>0 <= start <=
* limit</code>.
* @param limit the ending index, exclusive; <code>start <= limit <=
* length()</code>.
* @param dest the destination index. The characters from
* <code>start..limit-1</code> will be copied to <code>dest</code>.
* Implementations of this method may assume that <code>dest <= start ||
* dest >= limit</code>.
* @stable */
virtual void copy(int32_t start, int32_t limit, int32_t dest) = 0;
protected:
/**
* Default constructor.
*/
Replaceable();
/**
* Virtual version of length().
*/
virtual int32_t getLength() const = 0;
/**
* Virtual version of charAt().
*/
virtual UChar getCharAt(int32_t offset) const = 0;
/**
* Virtual version of char32At().
*/
virtual UChar32 getChar32At(int32_t offset) const = 0;
};
inline Replaceable::Replaceable() {}
inline Replaceable::~Replaceable() {}
inline int32_t
Replaceable::length() const {
return getLength();
}
inline UChar
Replaceable::charAt(int32_t offset) const {
return getCharAt(offset);
}
inline UChar32
Replaceable::char32At(int32_t offset) const {
return getChar32At(offset);
}
U_NAMESPACE_END
#endif