ICU 59.1  59.1
Public Member Functions | Protected Member Functions
icu::Replaceable Class Referenceabstract

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:
icu::UObject icu::UMemory icu::UnicodeString

Public Member Functions

virtual ~Replaceable ()
 Destructor. More...
 
int32_t length () const
 Returns the number of 16-bit code units in the text. More...
 
char16_t charAt (int32_t offset) const
 Returns the 16-bit code unit at the given offset into the text. More...
 
UChar32 char32At (int32_t offset) const
 Returns the 32-bit code point at the given 16-bit offset into the text. More...
 
virtual void extractBetween (int32_t start, int32_t limit, UnicodeString &target) const =0
 Copies characters in the range [start, limit) into the UnicodeString target. More...
 
virtual void handleReplaceBetween (int32_t start, int32_t limit, const UnicodeString &text)=0
 Replaces a substring of this object with the given text. More...
 
virtual void copy (int32_t start, int32_t limit, int32_t dest)=0
 Copies a substring of this object, retaining metadata. More...
 
virtual UBool hasMetaData () const
 Returns true if this object contains metadata. More...
 
virtual Replaceableclone () const
 Clone this object, an instance of a subclass of Replaceable. More...
 
- Public Member Functions inherited from icu::UObject
virtual ~UObject ()
 Destructor. More...
 
virtual UClassID getDynamicClassID () const
 ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class. More...
 

Protected Member Functions

 Replaceable ()
 Default constructor. More...
 
virtual int32_t getLength () const =0
 Virtual version of length(). More...
 
virtual char16_t getCharAt (int32_t offset) const =0
 Virtual version of charAt(). More...
 
virtual UChar32 getChar32At (int32_t offset) const =0
 Virtual version of char32At(). More...
 

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:

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

Author
Alan Liu
Stable:
ICU 2.0

Definition at line 73 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 242 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
offsetan integer between 0 and length()-1 inclusive
Returns
32-bit code point of text at given offset
Stable:
ICU 1.8

Definition at line 255 of file rep.h.

References U_NAMESPACE_END.

§ 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
offsetan integer between 0 and length()-1 inclusive
Returns
16-bit code unit of text at given offset
Stable:
ICU 1.8

Definition at line 250 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 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.

Returns
a clone of this object
See also
getDynamicClassID
Stable:
ICU 2.6

Reimplemented in icu::UnicodeString.

Referenced by icu::UnicodeString::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
startthe beginning index, inclusive; 0 <= start <= limit.
limitthe ending index, exclusive; start <= limit <= length().
destthe 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
startoffset of first character which will be copied
limitoffset immediately following the last character to be copied
targetUnicodeString 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.

Referenced by icu::UnicodeString::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.

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

§ getLength()

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

Virtual version of length().

Stable:
ICU 2.4

Implemented in icu::UnicodeString.

Referenced by icu::UnicodeString::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
startthe beginning index, inclusive; 0 <= start <= limit.
limitthe ending index, exclusive; start <= limit <= length().
textthe 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 ( void  ) 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 245 of file rep.h.

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


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