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-rw-r--r-- | intl/icu/source/common/unicode/rep.h | 266 |
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diff --git a/intl/icu/source/common/unicode/rep.h b/intl/icu/source/common/unicode/rep.h new file mode 100644 index 0000000000..7115c97b82 --- /dev/null +++ b/intl/icu/source/common/unicode/rep.h @@ -0,0 +1,266 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +************************************************************************** +* 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/utypes.h" + +#if U_SHOW_CPLUSPLUS_API + +#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 char16_t 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 nullptr is returned. + * 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 char16_t 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 char16_t +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 /* U_SHOW_CPLUSPLUS_API */ + +#endif |