Replaceable 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. More...

#include <rep.h>

Inheritance diagram for icu::Replaceable:

Public Member Functions
virtual	~Replaceable ()
	Destructor.

int32_t	length () const
	Returns the number of 16-bit code units in the text.

char16_t	charAt (int32_t offset) const
	Returns the 16-bit code unit at the given offset into the text.

UChar32	char32At (int32_t offset) const
	Returns the 32-bit code point at the given 16-bit offset into the text.

virtual void	extractBetween (int32_t start, int32_t limit, UnicodeString &target) const =0
	Copies characters in the range [`start`, `limit`) into the UnicodeString `target`.

virtual void	handleReplaceBetween (int32_t start, int32_t limit, const UnicodeString &text)=0
	Replaces a substring of this object with the given text.

virtual void	copy (int32_t start, int32_t limit, int32_t dest)=0
	Copies a substring of this object, retaining metadata.

virtual UBool	hasMetaData () const
	Returns true if this object contains metadata.

virtual Replaceable *	clone () const
	Clone this object, an instance of a subclass of Replaceable.

Public Member Functions inherited from icu::UObject
virtual	~UObject ()
	Destructor.

virtual UClassID	getDynamicClassID () const
	ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.

Protected Member Functions
	Replaceable ()
	Default constructor.

virtual int32_t	getLength () const =0
	Virtual version of length().

virtual char16_t	getCharAt (int32_t offset) const =0
	Virtual version of charAt().

virtual UChar32	getChar32At (int32_t offset) const =0
	Virtual version of char32At().

Detailed Description

Replaceable 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.

An implicit aspect of the Replaceable 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".

Replaceable 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.

Replaceable also includes API to access characters in the string: length(), charAt(), char32At(), and extractBetween().

For a subclass to support metadata, typical behavior of replace() is the following:

Set the metadata of the new text to the metadata of the first character replaced
If no characters are replaced, use the metadata of the previous character
If there is no previous character (i.e. start == 0), use the following character
If there is no following character (i.e. the replaceable was empty), use default metadata.
If the code point U+FFFF is seen, it should be interpreted as a special marker having no metadata

If this is not the behavior, the subclass should document any differences.

Author: Alan Liu

Stable:: ICU 2.0

Definition at line 77 of file rep.h.

Constructor & Destructor Documentation

◆ ~Replaceable()

virtual icu::Replaceable::~Replaceable ( )

virtual

Destructor.

Stable:: ICU 2.0

◆ Replaceable()

icu::Replaceable::Replaceable ( )

inlineprotected

Default constructor.

Stable:: ICU 2.4

Definition at line 243 of file rep.h.

Member Function Documentation

◆ char32At()

UChar32 icu::Replaceable::char32At ( int32_t offset ) const

inline

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.

Parameters

offset an integer between 0 and length()-1 inclusive

Returns: 32-bit code point of text at given offset

Stable:: ICU 1.8

Definition at line 256 of file rep.h.

◆ charAt()

char16_t icu::Replaceable::charAt ( int32_t offset ) const

inline

Returns the 16-bit code unit at the given offset into the text.

Parameters

offset an integer between 0 and length()-1 inclusive

Returns: 16-bit code unit of text at given offset

Stable:: ICU 1.8

Definition at line 251 of file rep.h.

◆ clone()

virtual Replaceable * icu::Replaceable::clone ( ) const

virtual

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.

Returns: a clone of this object

See also: getDynamicClassID

Stable:: ICU 2.6

Reimplemented in icu::UnicodeString.

◆ copy()

virtual void icu::Replaceable::copy	(	int32_t	start,
		int32_t	limit,
		int32_t	dest
	)

pure virtual

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.

Parameters

start	the beginning index, inclusive; `0 <= start <= limit`.
limit	the ending index, exclusive; `start <= limit <= length()`.
dest	the destination index. The characters from `start..limit-1` will be copied to `dest`. Implementations of this method may assume that `dest <= start \|\| dest >= limit`.

Stable:: ICU 2.0

Implemented in icu::UnicodeString.

◆ extractBetween()

virtual void icu::Replaceable::extractBetween	(	int32_t	start,
		int32_t	limit,
		UnicodeString &	target
	)		const

pure virtual

Copies characters in the range [start, limit) into the UnicodeString target.

Parameters

start	offset of first character which will be copied
limit	offset immediately following the last character to be copied
target	UnicodeString into which to copy characters.

Returns: A reference to target

Stable:: ICU 2.1

Implemented in icu::UnicodeString.

◆ getChar32At()

virtual UChar32 icu::Replaceable::getChar32At ( int32_t offset ) const

protectedpure virtual

Virtual version of char32At().

Stable:: ICU 2.4

Implemented in icu::UnicodeString.

◆ getCharAt()

virtual char16_t icu::Replaceable::getCharAt ( int32_t offset ) const

protectedpure virtual

Virtual version of charAt().

Stable:: ICU 2.4

Implemented in icu::UnicodeString.

◆ getLength()

virtual int32_t icu::Replaceable::getLength ( ) const

protectedpure virtual

Virtual version of length().

Stable:: ICU 2.4

Implemented in icu::UnicodeString.

◆ handleReplaceBetween()

virtual void icu::Replaceable::handleReplaceBetween	(	int32_t	start,
		int32_t	limit,
		const UnicodeString &	text
	)

pure virtual

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.

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.

Parameters

start	the beginning index, inclusive; `0 <= start <= limit`.
limit	the ending index, exclusive; `start <= limit <= length()`.
text	the text to replace characters `start` to `limit - 1`

Stable:: ICU 2.0

Implemented in icu::UnicodeString.

◆ hasMetaData()

virtual UBool icu::Replaceable::hasMetaData ( ) const

virtual

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.

Returns: true if this object contains metadata

Stable:: ICU 2.2

Reimplemented in icu::UnicodeString.

◆ length()

int32_t icu::Replaceable::length ( ) const

inline

Returns the number of 16-bit code units in the text.

Returns: number of 16-bit code units in text

Stable:: ICU 1.8

Definition at line 246 of file rep.h.

Referenced by icu::UnicodeString::toUTF8String().

The documentation for this class was generated from the following file:

common/unicode/rep.h

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Replaceable()

◆ Replaceable()

Member Function Documentation

◆ char32At()

◆ charAt()

◆ clone()

◆ copy()

◆ extractBetween()

◆ getChar32At()

◆ getCharAt()

◆ getLength()

◆ handleReplaceBetween()

◆ hasMetaData()

◆ length()