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Abstract class that defines an API for iteration on text objects.More...

#include <chariter.h>

Inheritance diagram for icu::CharacterIterator:

Public Types
enum	EOrigin {kStart,kCurrent,kEnd }
	Origin enumeration for themove() andmove32() functions.More...

Public Types inherited fromicu::ForwardCharacterIterator
enum	{DONE = 0xffff }
	Value returned by most ofForwardCharacterIterator's functions when the iterator has reached the limits of its iteration.More...

Public Member Functions
virtual	~CharacterIterator ()
	Destructor.More...

virtualCharacterIterator *	clone () const =0
	Returns a pointer to a newCharacterIterator of the same concrete class as this one, and referring to the same character in the same text-storage object as this one.More...

virtual char16_t	first ()=0
	Sets the iterator to refer to the first code unit in its iteration range, and returns that code unit.More...

virtual char16_t	firstPostInc ()
	Sets the iterator to refer to the first code unit in its iteration range, returns that code unit, and moves the position to the second code unit.More...

virtualUChar32	first32 ()=0
	Sets the iterator to refer to the first code point in its iteration range, and returns that code unit, This can be used to begin an iteration withnext32().More...

virtualUChar32	first32PostInc ()
	Sets the iterator to refer to the first code point in its iteration range, returns that code point, and moves the position to the second code point.More...

int32_t	setToStart ()
	Sets the iterator to refer to the first code unit or code point in its iteration range.More...

virtual char16_t	last ()=0
	Sets the iterator to refer to the last code unit in its iteration range, and returns that code unit.More...

virtualUChar32	last32 ()=0
	Sets the iterator to refer to the last code point in its iteration range, and returns that code unit.More...

int32_t	setToEnd ()
	Sets the iterator to the end of its iteration range, just behind the last code unit or code point.More...

virtual char16_t	setIndex (int32_t position)=0
	Sets the iterator to refer to the "position"-th code unit in the text-storage object the iterator refers to, and returns that code unit.More...

virtualUChar32	setIndex32 (int32_t position)=0
	Sets the iterator to refer to the beginning of the code point that contains the "position"-th code unit in the text-storage object the iterator refers to, and returns that code point.More...

virtual char16_t	current () const =0
	Returns the code unit the iterator currently refers to.More...

virtualUChar32	current32 () const =0
	Returns the code point the iterator currently refers to.More...

virtual char16_t	next ()=0
	Advances to the next code unit in the iteration range (towardendIndex()), and returns that code unit.More...

virtualUChar32	next32 ()=0
	Advances to the next code point in the iteration range (towardendIndex()), and returns that code point.More...

virtual char16_t	previous ()=0
	Advances to the previous code unit in the iteration range (towardstartIndex()), and returns that code unit.More...

virtualUChar32	previous32 ()=0
	Advances to the previous code point in the iteration range (towardstartIndex()), and returns that code point.More...

virtualUBool	hasPrevious ()=0
	Returns false if there are no more code units or code points before the current position in the iteration range.More...

int32_t	startIndex () const
	Returns the numeric index in the underlying text-storage object of the character returned byfirst().More...

int32_t	endIndex () const
	Returns the numeric index in the underlying text-storage object of the position immediately BEYOND the character returned bylast().More...

int32_t	getIndex () const
	Returns the numeric index in the underlying text-storage object of the character the iterator currently refers to (i.e., the character returned bycurrent()).More...

int32_t	getLength () const
	Returns the length of the entire text in the underlying text-storage object.More...

virtual int32_t	move (int32_t delta,EOrigin origin)=0
	Moves the current position relative to the start or end of the iteration range, or relative to the current position itself.More...

virtual int32_t	move32 (int32_t delta,EOrigin origin)=0
	Moves the current position relative to the start or end of the iteration range, or relative to the current position itself.More...

virtual void	getText (UnicodeString &result)=0
	Copies the text under iteration into theUnicodeString referred to by "result".More...

Public Member Functions inherited fromicu::ForwardCharacterIterator
virtual	~ForwardCharacterIterator ()
	Destructor.More...

virtual bool	operator== (constForwardCharacterIterator &that) const =0
	Returns true when both iterators refer to the same character in the same character-storage object.More...

bool	operator!= (constForwardCharacterIterator &that) const
	Returns true when the iterators refer to different text-storage objects, or to different characters in the same text-storage object.More...

virtual int32_t	hashCode () const =0
	Generates a hash code for this iterator.More...

virtualUClassID	getDynamicClassID () const override=0
	Returns a UClassID for thisForwardCharacterIterator ("poor man'sRTTI").More...

virtual char16_t	nextPostInc ()=0
	Gets the current code unit for returning and advances to the next code unit in the iteration range (toward endIndex()).More...

virtualUChar32	next32PostInc ()=0
	Gets the current code point for returning and advances to the next code point in the iteration range (toward endIndex()).More...

virtualUBool	hasNext ()=0
	Returns false if there are no more code units or code points at or after the current position in the iteration range.More...

Public Member Functions inherited fromicu::UObject
virtual	~UObject ()
	Destructor.More...

Protected Member Functions
	CharacterIterator ()
	Empty constructor.More...

	CharacterIterator (int32_t length)
	Constructor, just setting the length field in this base class.More...

	CharacterIterator (int32_t length, int32_t position)
	Constructor, just setting the length and position fields in this base class.More...

	CharacterIterator (int32_t length, int32_t textBegin, int32_t textEnd, int32_t position)
	Constructor, just setting the length, start, end, and position fields in this base class.More...

	CharacterIterator (constCharacterIterator &that)
	Copy constructor.More...

CharacterIterator &	operator= (constCharacterIterator &that)
	Assignment operator.More...

Protected Member Functions inherited fromicu::ForwardCharacterIterator
	ForwardCharacterIterator ()
	Default constructor to be overridden in the implementing class.More...

	ForwardCharacterIterator (constForwardCharacterIterator &other)
	Copy constructor to be overridden in the implementing class.More...

ForwardCharacterIterator &	operator= (constForwardCharacterIterator &)
	Assignment operator to be overridden in the implementing class.More...

Protected Attributes
int32_t	textLength
	Base class text length field.More...

int32_t	pos
	Base class field for the current position.More...

int32_t	begin
	Base class field for the start of the iteration range.More...

int32_t	end
	Base class field for the end of the iteration range.More...

Detailed Description

Abstract class that defines an API for iteration on text objects.

This is an interface for forward and backward iteration and random access into a text object.

The API provides backward compatibility to the Java and older ICUCharacterIterator classes but extends them significantly:

CharacterIterator is now a subclass ofForwardCharacterIterator.
While the old API functions provided forward iteration with "pre-increment" semantics, the new one also provides functions with "post-increment" semantics. They are more efficient and should be the preferred iterator functions for new implementations. The backward iteration always had "pre-decrement" semantics, which are efficient.
Just likeForwardCharacterIterator, it provides access to both code units and code points. Code point access versions are available for the old and the new iteration semantics.
There are new functions for setting and moving the current position without returning a character, for efficiency.

SeeForwardCharacterIterator for examples for using the new forward iteration functions. For backward iteration, there is also ahasPrevious() function that can be used analogously tohasNext(). The old functions work as before and are shown below.

Examples for some of the new functions:

Forward iteration withhasNext():

void forward1(CharacterIterator &it) {

UChar32 c;

for(it.setToStart(); it.hasNext();) {

c=it.next32PostInc();

// use c

}

icu::CharacterIterator::CharacterIterator

CharacterIterator()

Empty constructor.

UChar32

int32_t UChar32

Define UChar32 as a type for single Unicode code points.

Definition:umachine.h:449

Forward iteration more similar to loops with the old forward iteration, showing a way to convert simple for() loops:

void forward2(CharacterIterator &it) {

char16_t c;

for(c=it.firstPostInc(); c!=CharacterIterator::DONE; c=it.nextPostInc()) {

// use c

}

Backward iteration withsetToEnd() andhasPrevious():

void backward1(CharacterIterator &it) {

UChar32 c;

for(it.setToEnd(); it.hasPrevious();) {

c=it.previous32();

// use c

}

Backward iteration with a more traditional for() loop:

void backward2(CharacterIterator &it) {

char16_t c;

for(c=it.last(); c!=CharacterIterator::DONE; c=it.previous()) {

// use c

}

Example for random access:

void random(CharacterIterator &it) {

// set to the third code point from the beginning

it.move32(3, CharacterIterator::kStart);

// get a code point from here without moving the position

UChar32 c=it.current32();

// get the position

int32_tpos=it.getIndex();

// get the previous code unit

char16_t u=it.previous();

// move back one more code unit

it.move(-1, CharacterIterator::kCurrent);

// set the position back to where it was

// and read the same code point c and move beyond it

it.setIndex(pos);

if(c!=it.next32PostInc()) {

exit(1);// CharacterIterator inconsistent

}

icu::CharacterIterator::pos

int32_t pos

Base class field for the current position.

Definition:chariter.h:680

Examples, especially for the old API:

Function processing characters, in this example simple output

void processChar( char16_t c )
{
    cout <<" " << c;
}

Traverse the text from start to finish

void traverseForward(CharacterIterator& iter)
{
for(char16_t c = iter.first(); c != CharacterIterator::DONE; c = iter.next()) {
        processChar(c);
    }
}

Traverse the text backwards, from end to start

void traverseBackward(CharacterIterator& iter)
{
for(char16_t c = iter.last(); c != CharacterIterator::DONE; c = iter.previous()) {
        processChar(c);
    }
}

Traverse both forward and backward from a given position in the text. Calls to notBoundary() in this example represents some additional stopping criteria.

void traverseOut(CharacterIterator& iter, int32_tpos)
{
     char16_t c;
for (c = iter.setIndex(pos);
     c != CharacterIterator::DONE && (Unicode::isLetter(c) || Unicode::isDigit(c));
         c = iter.next()) {}
     int32_tend = iter.getIndex();
for (c = iter.setIndex(pos);
         c != CharacterIterator::DONE && (Unicode::isLetter(c) || Unicode::isDigit(c));
         c = iter.previous()) {}
     int32_t start = iter.getIndex() + 1;
     cout <<"start: " << start <<" end: " <<end << endl;
for (c = iter.setIndex(start); iter.getIndex() <end; c = iter.next() ) {
         processChar(c);
    }
 }
icu::CharacterIterator::end
int32_t end
Base class field for the end of the iteration range.
Definition:chariter.h:692

Creating aStringCharacterIterator and calling the test functions

void CharacterIterator_Example(void )
 {
     cout << endl <<"===== CharacterIterator_Example: =====" << endl;
     UnicodeString text("Ein kleiner Satz.");
     StringCharacterIterator iterator(text);
     cout <<"----- traverseForward: -----------" << endl;
     traverseForward( iterator );
     cout << endl << endl <<"----- traverseBackward: ----------" << endl;
     traverseBackward( iterator );
     cout << endl << endl <<"----- traverseOut: ---------------" << endl;
     traverseOut( iterator, 7 );
     cout << endl << endl <<"-----" << endl;
 }

Stable:: ICU 2.0

Definition at line361 of filechariter.h.

Member Enumeration Documentation

◆ EOrigin

enumicu::CharacterIterator::EOrigin

Origin enumeration for themove() andmove32() functions.

Stable:: ICU 2.0

Definition at line367 of filechariter.h.

Constructor & Destructor Documentation

◆ ~CharacterIterator()

virtual icu::CharacterIterator::~CharacterIterator

(

)

virtual

Destructor.

Stable:: ICU 2.0

◆ CharacterIterator()[1/5]

icu::CharacterIterator::CharacterIterator

(

)

protected

Empty constructor.

Stable:: ICU 2.0

◆ CharacterIterator()[2/5]

icu::CharacterIterator::CharacterIterator

(

int32_t

length

)

protected

Constructor, just setting the length field in this base class.

Stable:: ICU 2.0

◆ CharacterIterator()[3/5]

icu::CharacterIterator::CharacterIterator	(	int32_t	length,
		int32_t	position
	)

protected

Constructor, just setting the length and position fields in this base class.

Stable:: ICU 2.0

◆ CharacterIterator()[4/5]

icu::CharacterIterator::CharacterIterator	(	int32_t	length,
		int32_t	textBegin,
		int32_t	textEnd,
		int32_t	position
	)

protected

Constructor, just setting the length, start, end, and position fields in this base class.

Stable:: ICU 2.0

◆ CharacterIterator()[5/5]

icu::CharacterIterator::CharacterIterator

(

constCharacterIterator &

that

)

protected

Copy constructor.

Parameters

that	TheCharacterIterator to be copied

Stable:: ICU 2.0

Member Function Documentation

◆ clone()

virtualCharacterIterator* icu::CharacterIterator::clone

(

)

const

pure virtual

Returns a pointer to a newCharacterIterator of the same concrete class as this one, and referring to the same character in the same text-storage object as this one.

The caller is responsible for deleting the new clone.

Returns: a pointer to a newCharacterIterator

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator, andicu::StringCharacterIterator.

◆ current()

virtual char16_t icu::CharacterIterator::current

(

)

const

pure virtual

Returns the code unit the iterator currently refers to.

Returns: the current code unit.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ current32()

virtualUChar32 icu::CharacterIterator::current32

(

)

const

pure virtual

Returns the code point the iterator currently refers to.

Returns: the current code point.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ endIndex()

int32_t icu::CharacterIterator::endIndex

(

)

const

inline

Returns the numeric index in the underlying text-storage object of the position immediately BEYOND the character returned bylast().

Returns: the numeric index in the underlying text-storage object of the position immediately BEYOND the character returned bylast().

Stable:: ICU 2.0

Definition at line716 of filechariter.h.

◆ first()

virtual char16_t icu::CharacterIterator::first

(

)

pure virtual

Sets the iterator to refer to the first code unit in its iteration range, and returns that code unit.

This can be used to begin an iteration withnext().

Returns: the first code unit in its iteration range.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ first32()

virtualUChar32 icu::CharacterIterator::first32

(

)

pure virtual

Sets the iterator to refer to the first code point in its iteration range, and returns that code unit, This can be used to begin an iteration withnext32().

Note that an iteration withnext32PostInc(), beginning with, e.g.,setToStart() orfirstPostInc(), is more efficient.

Returns: the first code point in its iteration range.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ first32PostInc()

virtualUChar32 icu::CharacterIterator::first32PostInc

(

)

virtual

Sets the iterator to refer to the first code point in its iteration range, returns that code point, and moves the position to the second code point.

This is an alternative tosetToStart() for forward iteration withnext32PostInc().

Returns: the first code point in its iteration range.

Stable:: ICU 2.0

Reimplemented inicu::UCharCharacterIterator.

◆ firstPostInc()

virtual char16_t icu::CharacterIterator::firstPostInc

(

)

virtual

Sets the iterator to refer to the first code unit in its iteration range, returns that code unit, and moves the position to the second code unit.

This is an alternative tosetToStart() for forward iteration withnextPostInc().

Returns: the first code unit in its iteration range.

Stable:: ICU 2.0

Reimplemented inicu::UCharCharacterIterator.

◆ getIndex()

int32_t icu::CharacterIterator::getIndex

(

)

const

inline

Returns the numeric index in the underlying text-storage object of the character the iterator currently refers to (i.e., the character returned bycurrent()).

Returns: the numeric index in the text-storage object of the character the iterator currently refers to

Stable:: ICU 2.0

Definition at line721 of filechariter.h.

◆ getLength()

int32_t icu::CharacterIterator::getLength

(

)

const

inline

Returns the length of the entire text in the underlying text-storage object.

Returns: the length of the entire text in the text-storage object

Stable:: ICU 2.0

Definition at line726 of filechariter.h.

◆ getText()

virtual void icu::CharacterIterator::getText

(

UnicodeString &

result

)

pure virtual

Copies the text under iteration into theUnicodeString referred to by "result".

Parameters

result

Receives a copy of the text under iteration.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator, andicu::StringCharacterIterator.

◆ hasPrevious()

virtualUBool icu::CharacterIterator::hasPrevious

(

)

pure virtual

Returns false if there are no more code units or code points before the current position in the iteration range.

This is used withprevious() orprevious32() in backward iteration.

Returns: false if there are no more code units or code points before the current position in the iteration range, return true otherwise.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ last()

virtual char16_t icu::CharacterIterator::last

(

)

pure virtual

Sets the iterator to refer to the last code unit in its iteration range, and returns that code unit.

This can be used to begin an iteration withprevious().

Returns: the last code unit.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ last32()

virtualUChar32 icu::CharacterIterator::last32

(

)

pure virtual

Sets the iterator to refer to the last code point in its iteration range, and returns that code unit.

This can be used to begin an iteration withprevious32().

Returns: the last code point.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ move()

virtual int32_t icu::CharacterIterator::move	(	int32_t	delta,
		EOrigin	origin
	)

pure virtual

Moves the current position relative to the start or end of the iteration range, or relative to the current position itself.

The movement is expressed in numbers of code units forward or backward by specifying a positive or negative delta.

Parameters

delta	the position relative to origin. A positive delta means forward; a negative delta means backward.
origin	Origin enumeration {kStart, kCurrent, kEnd}

Returns: the new position

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ move32()

virtual int32_t icu::CharacterIterator::move32	(	int32_t	delta,
		EOrigin	origin
	)

pure virtual

Moves the current position relative to the start or end of the iteration range, or relative to the current position itself.

The movement is expressed in numbers of code points forward or backward by specifying a positive or negative delta.

Parameters

delta	the position relative to origin. A positive delta means forward; a negative delta means backward.
origin	Origin enumeration {kStart, kCurrent, kEnd}

Returns: the new position

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ next()

virtual char16_t icu::CharacterIterator::next

(

)

pure virtual

Advances to the next code unit in the iteration range (towardendIndex()), and returns that code unit.

If there are no more code units to return, returns DONE.

Returns: the next code unit.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ next32()

virtualUChar32 icu::CharacterIterator::next32

(

)

pure virtual

Advances to the next code point in the iteration range (towardendIndex()), and returns that code point.

If there are no more code points to return, returns DONE. Note that iteration with "pre-increment" semantics is less efficient than iteration with "post-increment" semantics that is provided bynext32PostInc().

Returns: the next code point.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ operator=()

CharacterIterator& icu::CharacterIterator::operator=

(

constCharacterIterator &

that

)

protected

Assignment operator.

Sets thisCharacterIterator to have the same behavior, as the one passed in.

Parameters

that	TheCharacterIterator passed in.

Returns: the newly setCharacterIterator.

Stable:: ICU 2.0

◆ previous()

virtual char16_t icu::CharacterIterator::previous

(

)

pure virtual

Advances to the previous code unit in the iteration range (towardstartIndex()), and returns that code unit.

If there are no more code units to return, returns DONE.

Returns: the previous code unit.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ previous32()

virtualUChar32 icu::CharacterIterator::previous32

(

)

pure virtual

Advances to the previous code point in the iteration range (towardstartIndex()), and returns that code point.

If there are no more code points to return, returns DONE.

Returns: the previous code point.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ setIndex()

virtual char16_t icu::CharacterIterator::setIndex

(

int32_t

position

)

pure virtual

Sets the iterator to refer to the "position"-th code unit in the text-storage object the iterator refers to, and returns that code unit.

Parameters

position

the "position"-th code unit in the text-storage object

Returns: the "position"-th code unit.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ setIndex32()

virtualUChar32 icu::CharacterIterator::setIndex32

(

int32_t

position

)

pure virtual

Sets the iterator to refer to the beginning of the code point that contains the "position"-th code unit in the text-storage object the iterator refers to, and returns that code point.

The current position is adjusted to the beginning of the code point (its first code unit).

Parameters

position

the "position"-th code unit in the text-storage object

Returns: the "position"-th code point.

Stable:: ICU 2.0

Implemented inicu::UCharCharacterIterator.

◆ setToEnd()

int32_t icu::CharacterIterator::setToEnd

(

)

inline

Sets the iterator to the end of its iteration range, just behind the last code unit or code point.

This can be used to begin a backward iteration withprevious() orprevious32().

Returns: the end position of the iteration range

Stable:: ICU 2.0

Definition at line706 of filechariter.h.

◆ setToStart()

int32_t icu::CharacterIterator::setToStart

(

)

inline

Sets the iterator to refer to the first code unit or code point in its iteration range.

This can be used to begin a forward iteration withnextPostInc() ornext32PostInc().

Returns: the start position of the iteration range

Stable:: ICU 2.0

Definition at line701 of filechariter.h.

◆ startIndex()

int32_t icu::CharacterIterator::startIndex

(

)

const

inline

Returns the numeric index in the underlying text-storage object of the character returned byfirst().

Since it's possible to create an iterator that iterates across only part of a text-storage object, this number isn't necessarily 0.

Returns: the numeric index in the underlying text-storage object of the character returned byfirst().

Stable:: ICU 2.0

Definition at line711 of filechariter.h.

Field Documentation

◆ begin

int32_t icu::CharacterIterator::begin

protected

Base class field for the start of the iteration range.

Stable:: ICU 2.0

Definition at line686 of filechariter.h.

◆ end

int32_t icu::CharacterIterator::end

protected

Base class field for the end of the iteration range.

Stable:: ICU 2.0

Definition at line692 of filechariter.h.

◆ pos

int32_t icu::CharacterIterator::pos

protected

Base class field for the current position.

Stable:: ICU 2.0

Definition at line680 of filechariter.h.

◆ textLength

int32_t icu::CharacterIterator::textLength

protected

Base class text length field.

Necessary this for correctgetText() andhashCode().

Stable:: ICU 2.0

Definition at line674 of filechariter.h.

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

common/unicode/chariter.h

Movatterモバイル変換

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ EOrigin

Constructor & Destructor Documentation

◆ ~CharacterIterator()

◆ CharacterIterator()[1/5]

◆ CharacterIterator()[2/5]

◆ CharacterIterator()[3/5]

◆ CharacterIterator()[4/5]

◆ CharacterIterator()[5/5]

Member Function Documentation

◆ clone()

◆ current()

◆ current32()

◆ endIndex()

◆ first()

◆ first32()

◆ first32PostInc()

◆ firstPostInc()

◆ getIndex()

◆ getLength()

◆ getText()

◆ hasPrevious()

◆ last()

◆ last32()

◆ move()

◆ move32()

◆ next()

◆ next32()

◆ operator=()

◆ previous()

◆ previous32()

◆ setIndex()

◆ setIndex32()

◆ setToEnd()

◆ setToStart()

◆ startIndex()

Field Documentation

◆ begin

◆ end

◆ pos

◆ textLength