/* ************************************************************************** * Copyright (C) 1999-2012, 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/uobject.h" /** * \file * \brief C++ API: Replaceable String */ 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 metadata. Metadata is data * other than the Unicode characters returned by char32At(). One * example of metadata is style attributes; another is an edit * history, marking each character with an author and revision number. * * <p>An implicit aspect of the <code>Replaceable</code> API is that * during a replace operation, new characters take on the metadata 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 a start * offset and a limit offset. The range of characters thus specified * includes the characters at offset start..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>, * <code>char32At()</code>, and <code>extractBetween()</code>. * * <p>For a subclass to support metadata, typical behavior of * <code>replace()</code> is the following: * <ul> * <li>Set the metadata of the new text to the metadata of the first * character replaced</li> * <li>If no characters are replaced, use the metadata 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), use default metadata.<br> * <li>If the code point U+FFFF is seen, it should be interpreted as * a special marker having no metadata<li> * </li> * </ul> * If this is not the behavior, the subclass should document any differences. * @author Alan Liu * @stable ICU 2.0 */ class U_COMMON_API Replaceable : public UObject { public: /** * Destructor. * @stable ICU 2.0 */ virtual ~Replaceable(); /** * Returns the number of 16-bit code units in the text. * @return number of 16-bit code units in text * @stable ICU 1.8 */ inline int32_t length() const; /** * Returns the 16-bit code unit at the given offset into the text. * @param offset an integer between 0 and <code>length()</code>-1 * inclusive * @return 16-bit code unit of text at given offset * @stable ICU 1.8 */ inline UChar charAt(int32_t offset) const; /** * Returns the 32-bit code point at the given 16-bit offset into * the text. This assumes the text is stored as 16-bit code units * with surrogate pairs intermixed. If the offset of a leading or * trailing code unit of a surrogate pair is given, return the * code point of the surrogate pair. * * @param offset an integer between 0 and <code>length()</code>-1 * inclusive * @return 32-bit code point of text at given offset * @stable ICU 1.8 */ inline UChar32 char32At(int32_t offset) const; /** * Copies 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> * @stable ICU 2.1 */ virtual void extractBetween(int32_t start, int32_t limit, UnicodeString& target) const = 0; /** * Replaces a substring of this object with the given text. If the * characters being replaced have metadata, the new characters * that replace them should be given the same metadata. * * <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 metadata * should be unaffected. In addition, subclasses are encouraged to * check for initial and trailing identical characters, and make a * smaller replacement if possible. This will preserve as much * metadata 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 ICU 2.0 */ 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. /** * Copies a substring of this object, retaining metadata. * This method is used to duplicate or reorder substrings. * The destination index must not overlap the source range. * * @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 ICU 2.0 */ virtual void copy(int32_t start, int32_t limit, int32_t dest) = 0; /** * Returns true if this object contains metadata. If a * Replaceable object has metadata, calls to the Replaceable API * must be made so as to preserve metadata. If it does not, calls * to the Replaceable API may be optimized to improve performance. * The default implementation returns true. * @return true if this object contains metadata * @stable ICU 2.2 */ virtual UBool hasMetaData() const; /** * Clone this object, an instance of a subclass of Replaceable. * Clones can be used concurrently in multiple threads. * If a subclass does not implement clone(), or if an error occurs, * then NULL is returned. * The clone functions in all subclasses return a pointer to a Replaceable * because some compilers do not support covariant (same-as-this) * return types; cast to the appropriate subclass if necessary. * The caller must delete the clone. * * @return a clone of this object * * @see getDynamicClassID * @stable ICU 2.6 */ virtual Replaceable *clone() const; protected: /** * Default constructor. * @stable ICU 2.4 */ inline Replaceable(); /* * Assignment operator not declared. The compiler will provide one * which does nothing since this class does not contain any data members. * API/code coverage may show the assignment operator as present and * untested - ignore. * Subclasses need this assignment operator if they use compiler-provided * assignment operators of their own. An alternative to not declaring one * here would be to declare and empty-implement a protected or public one. Replaceable &Replaceable::operator=(const Replaceable &); */ /** * Virtual version of length(). * @stable ICU 2.4 */ virtual int32_t getLength() const = 0; /** * Virtual version of charAt(). * @stable ICU 2.4 */ virtual UChar getCharAt(int32_t offset) const = 0; /** * Virtual version of char32At(). * @stable ICU 2.4 */ virtual UChar32 getChar32At(int32_t offset) const = 0; }; 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); } // There is no rep.cpp, see unistr.cpp for Replaceable function implementations. U_NAMESPACE_END #endif