Transliterator is an abstract class that
* transliterates text from one format to another. The most common
* kind of transliterator is a script, or alphabet, transliterator.
* For example, a Russian to Latin transliterator changes Russian text
* written in Cyrillic characters to phonetically equivalent Latin
* characters. It does not translate Russian to English!
* Transliteration, unlike translation, operates on characters, without
* reference to the meanings of words and sentences.
*
* Although script conversion is its most common use, a
* transliterator can actually perform a more general class of tasks.
* In fact, Transliterator defines a very general API
* which specifies only that a segment of the input text is replaced
* by new text. The particulars of this conversion are determined
* entirely by subclasses of Transliterator.
*
*
Transliterators are stateless * *
Transliterator objects are stateless; they
* retain no information between calls to
* transliterate(). (However, this does not
* mean that threads may share transliterators without synchronizing
* them. Transliterators are not immutable, so they must be
* synchronized when shared between threads.) This1 might seem to
* limit the complexity of the transliteration operation. In
* practice, subclasses perform complex transliterations by delaying
* the replacement of text until it is known that no other
* replacements are possible. In other words, although the
* Transliterator objects are stateless, the source text
* itself embodies all the needed information, and delayed operation
* allows arbitrary complexity.
*
*
Batch transliteration * *
The simplest way to perform transliteration is all at once, on a
* string of existing text. This is referred to as batch
* transliteration. For example, given a string input
* and a transliterator t, the call
*
*
String result = t.transliterate(input);
* Keyboard transliteration * *
Somewhat more involved is keyboard, or incremental * transliteration. This is the transliteration of text that is * arriving from some source (typically the user's keyboard) one * character at a time, or in some other piecemeal fashion. * *
In keyboard transliteration, a Replaceable buffer
* stores the text. As text is inserted, as much as possible is
* transliterated on the fly. This means a GUI that displays the
* contents of the buffer may show text being modified as each new
* character arrives.
*
*
Consider the simple RuleBasedTransliterator:
*
*
* th>{theta}
* t>{tau}
*
* t>|{tau}
* {tau}h>{theta}
* transliterate(). Typically, the cursor will
* be coincident with the insertion point, but in a case like the one
* above, it will precede the insertion point.
*
* Keyboard transliteration methods maintain a set of three indices
* that are updated with each call to
* transliterate(), including the cursor, start,
* and limit. Since these indices are changed by the method, they are
* passed in an int[] array. The START index
* marks the beginning of the substring that the transliterator will
* look at. It is advanced as text becomes committed (but it is not
* the committed index; that's the CURSOR). The
* CURSOR index, described above, marks the point at
* which the transliterator last stopped, either because it reached
* the end, or because it required more characters to disambiguate
* between possible inputs. The CURSOR can also be
* explicitly set by rules in a RuleBasedTransliterator.
* Any characters before the CURSOR index are frozen;
* future keyboard transliteration calls within this input sequence
* will not change them. New text is inserted at the
* LIMIT index, which marks the end of the substring that
* the transliterator looks at.
*
*
Because keyboard transliteration assumes that more characters
* are to arrive, it is conservative in its operation. It only
* transliterates when it can do so unambiguously. Otherwise it waits
* for more characters to arrive. When the client code knows that no
* more characters are forthcoming, perhaps because the user has
* performed some input termination operation, then it should call
* finishTransliteration() to complete any
* pending transliterations.
*
*
Inverses * *
Pairs of transliterators may be inverses of one another. For
* example, if transliterator A transliterates characters by
* incrementing their Unicode value (so "abc" -> "def"), and
* transliterator B decrements character values, then A
* is an inverse of B and vice versa. If we compose A
* with B in a compound transliterator, the result is the
* indentity transliterator, that is, a transliterator that does not
* change its input text.
*
* The Transliterator method getInverse()
* returns a transliterator's inverse, if one exists, or
* null otherwise. However, the result of
* getInverse() usually will not be a true
* mathematical inverse. This is because true inverse transliterators
* are difficult to formulate. For example, consider two
* transliterators: AB, which transliterates the character 'A'
* to 'B', and BA, which transliterates 'B' to 'A'. It might
* seem that these are exact inverses, since
*
*
"A" x AB -> "B"* * where 'x' represents transliteration. However, * *
* "B" x BA -> "A"
"ABCD" x AB -> "BBCD"* * so AB composed with BA is not the * identity. Nonetheless, BA may be usefully considered to be * AB's inverse, and it is on this basis that * AB
* "BBCD" x BA -> "AACD"
.getInverse() could legitimately return
* BA.
*
* IDs and display names * *
A transliterator is designated by a short identifier string or * ID. IDs follow the format source-destination, * where source describes the entity being replaced, and * destination describes the entity replacing * source. The entities may be the names of scripts, * particular sequences of characters, or whatever else it is that the * transliterator converts to or from. For example, a transliterator * from Russian to Latin might be named "Russian-Latin". A * transliterator from keyboard escape sequences to Latin-1 characters * might be named "KeyboardEscape-Latin1". By convention, system * entity names are in English, with the initial letters of words * capitalized; user entity names may follow any format so long as * they do not contain dashes. * *
In addition to programmatic IDs, transliterator objects have * display names for presentation in user interfaces, returned by * {@link #getDisplayName()}. * *
Factory methods and registration * *
In general, client code should use the factory method
* {@link #createInstance()} to obtain an instance of a
* transliterator given its ID. Valid IDs may be enumerated using
* getAvailableIDs(). Since transliterators are mutable,
* multiple calls to {@link #createInstance()} with the same ID will
* return distinct objects.
*
*
In addition to the system transliterators registered at startup,
* user transliterators may be registered by calling
* registerInstance() at run time. A registered instance
* acts a template; future calls to {@link #createInstance()} with the ID
* of the registered object return clones of that object. Thus any
* object passed to registerInstance() must implement
* clone() propertly. To register a transliterator subclass
* without instantiating it (until it is needed), users may call
* registerClass(). In this case, the objects are
* instantiated by invoking the zero-argument public constructor of
* the class.
*
*
Subclassing
*
* Subclasses must implement the abstract method
* handleTransliterate().
Subclasses should override
* the transliterate() method taking a
* Replaceable and the transliterate()
* method taking a String and StringBuffer
* if the performance of these methods can be improved over the
* performance obtained by the default implementations in this class.
*
* @author Alan Liu
* @stable
*/
class U_I18N_API Transliterator : public UObject {
private:
/**
* Programmatic name, e.g., "Latin-Arabic".
*/
UnicodeString ID;
/**
* This transliterator's filter. Any character for which
* filter.contains() returns false will not be
* altered by this transliterator. If filter is
* null then no filtering is applied.
*/
UnicodeFilter* filter;
int32_t maximumContextLength;
public:
/**
* A context integer or pointer for a factory function, passed by
* value.
*/
union Token {
int32_t integer;
void* pointer;
};
/**
* Return a token containing an integer.
* @return a token containing an integer.
*/
inline static Token integerToken(int32_t);
/**
* Return a token containing a pointer.
* @return a token containing a pointer.
*/
inline static Token pointerToken(void*);
/**
* A function that creates and returns a Transliterator. When
* invoked, it will be passed the ID string that is being
* instantiated, together with the context pointer that was passed
* in when the factory function was first registered. Many
* factory functions will ignore both parameters, however,
* functions that are registered to more than one ID may use the
* ID or the context parameter to parameterize the transliterator
* they create.
* @param ID the string identifier for this transliterator
* @param context a context pointer that will be stored and
* later passed to the factory function when an ID matching
* the registration ID is being instantiated with this factory.
*/
typedef Transliterator* (*Factory)(const UnicodeString& ID, Token context);
protected:
/**
* Default constructor.
* @param ID the string identifier for this transliterator
* @param adoptedFilter the filter. Any character for which
* filter.contains() returns false will not be
* altered by this transliterator. If filter is
* null then no filtering is applied.
*/
Transliterator(const UnicodeString& ID, UnicodeFilter* adoptedFilter);
/**
* Copy constructor.
*/
Transliterator(const Transliterator&);
/**
* Assignment operator.
*/
Transliterator& operator=(const Transliterator&);
/**
* Create a transliterator from a basic ID. This is an ID
* containing only the forward direction source, target, and
* variant.
* @param id a basic ID of the form S-T or S-T/V.
* @param canon canonical ID to assign to the object, or
* NULL to leave the ID unchanged
* @return a newly created Transliterator or null if the ID is
* invalid.
*/
static Transliterator* createBasicInstance(const UnicodeString& id,
const UnicodeString* canon);
friend class TransliteratorParser; // for parseID()
friend class TransliteratorIDParser; // for createBasicInstance()
public:
/**
* Destructor.
* @stable
*/
virtual ~Transliterator();
/**
* Implements Cloneable.
* All subclasses are encouraged to implement this method if it is
* possible and reasonable to do so. Subclasses that are to be
* registered with the system using registerInstance()
* are required to implement this method. If a subclass does not
* implement clone() properly and is registered with the system
* using registerInstance(), then the default clone() implementation
* will return null, and calls to createInstance() will fail.
*
* @return a copy of the object.
* @see #registerInstance
* @stable
*/
virtual Transliterator* clone() const { return 0; }
/**
* Transliterates a segment of a string, with optional filtering.
*
* @param text the string to be transliterated
* @param start the beginning index, inclusive; 0 <= start
* <= limit.
* @param limit the ending index, exclusive; start <= limit
* <= text.length().
* @return The new limit index. The text previously occupying [start,
* limit) has been transliterated, possibly to a string of a different
* length, at [start, new-limit), where
* new-limit is the return value. If the input offsets are out of bounds,
* the returned value is -1 and the input string remains unchanged.
* @stable
*/
virtual int32_t transliterate(Replaceable& text,
int32_t start, int32_t limit) const;
/**
* Transliterates an entire string in place. Convenience method.
* @param text the string to be transliterated
* @stable
*/
virtual void transliterate(Replaceable& text) const;
/**
* Transliterates the portion of the text buffer that can be
* transliterated unambiguosly after new text has been inserted,
* typically as a result of a keyboard event. The new text in
* insertion will be inserted into text
* at index.limit, advancing
* index.limit by insertion.length().
* Then the transliterator will try to transliterate characters of
* text between index.cursor and
* index.limit. Characters before
* index.cursor will not be changed.
*
*
Upon return, values in index will be updated.
* index.start will be advanced to the first
* character that future calls to this method will read.
* index.cursor and index.limit will
* be adjusted to delimit the range of text that future calls to
* this method may change.
*
*
Typical usage of this method begins with an initial call
* with index.start and index.limit
* set to indicate the portion of text to be
* transliterated, and index.cursor == index.start.
* Thereafter, index can be used without
* modification in future calls, provided that all changes to
* text are made via this method.
*
*
This method assumes that future calls may be made that will * insert new text into the buffer. As a result, it only performs * unambiguous transliterations. After the last call to this * method, there may be untransliterated text that is waiting for * more input to resolve an ambiguity. In order to perform these * pending transliterations, clients should call {@link * #finishTransliteration()} after the last call to this * method has been made. * * @param text the buffer holding transliterated and untransliterated text * @param index an array of three integers. * *
index.start: the beginning index,
* inclusive; 0 <= index.start <= index.limit.
*
* index.limit: the ending index, exclusive;
* index.start <= index.limit <= text.length().
* insertion is inserted at
* index.limit.
*
* index.cursor: the next character to be
* considered for transliteration; index.start <=
* index.cursor <= index.limit. Characters before
* index.cursor will not be changed by future calls
* to this method.index.limit. If null then no text
* is inserted.
* @param status Output param to filled in with a success or an error.
* @see #handleTransliterate
* @exception IllegalArgumentException if index
* is invalid
* @see UTransPosition
* @stable
*/
virtual void transliterate(Replaceable& text, UTransPosition& index,
const UnicodeString& insertion,
UErrorCode& status) const;
/**
* Transliterates the portion of the text buffer that can be
* transliterated unambiguosly after a new character has been
* inserted, typically as a result of a keyboard event. This is a
* convenience method; see {@link
* #transliterate(Replaceable, UTransPosition, UnicodeString)} for details.
* @param text the buffer holding transliterated and
* untransliterated text
* @param index an array of three integers. See {@link
* #transliterate(Replaceable, UTransPosition, UnicodeString)}.
* @param insertion text to be inserted and possibly
* transliterated into the translation buffer at
* index.limit.
* @param status Output param to filled in with a success or an error.
* @see #transliterate(Replaceable, UTransPosition, UnicodeString)
* @stable
*/
virtual void transliterate(Replaceable& text, UTransPosition& index,
UChar32 insertion,
UErrorCode& status) const;
/**
* Transliterates the portion of the text buffer that can be
* transliterated unambiguosly. This is a convenience method; see
* {@link #transliterate(Replaceable, UTransPosition, UnicodeString)} for
* details.
* @param text the buffer holding transliterated and
* untransliterated text
* @param index an array of three integers. See {@link
* #transliterate(Replaceable, UTransPosition, UnicodeString)}.
* @param status Output param to filled in with a success or an error.
* @see #transliterate(Replaceable, int[], String)
* @stable
*/
virtual void transliterate(Replaceable& text, UTransPosition& index,
UErrorCode& status) const;
/**
* Finishes any pending transliterations that were waiting for
* more characters. Clients should call this method as the last
* call after a sequence of one or more calls to
* transliterate().
* @param text the buffer holding transliterated and
* untransliterated text.
* @param index the array of indices previously passed to {@link
* #transliterate()}
* @stable
*/
virtual void finishTransliteration(Replaceable& text,
UTransPosition& index) const;
private:
/**
* This internal method does incremental transliteration. If the
* 'insertion' is non-null then we append it to 'text' before
* proceeding. This method calls through to the pure virtual
* framework method handleTransliterate() to do the actual
* work.
* @param text the buffer holding transliterated and
* untransliterated text
* @param index an array of three integers. See {@link
* #transliterate(Replaceable, int[], String)}.
* @param insertion text to be inserted and possibly
* transliterated into the translation buffer at
* index.limit.
* @param status Output param to filled in with a success or an error.
*/
void _transliterate(Replaceable& text,
UTransPosition& index,
const UnicodeString* insertion,
UErrorCode &status) const;
protected:
/**
* Abstract method that concrete subclasses define to implement
* their transliteration algorithm. This method handles both
* incremental and non-incremental transliteration. Let
* originalStart refer to the value of
* pos.start upon entry.
*
* incremental is false, then this method
* should transliterate all characters between
* pos.start and pos.limit. Upon return
* pos.start must == pos.limit.incremental is true, then this method
* should transliterate all characters between
* pos.start and pos.limit that can be
* unambiguously transliterated, regardless of future insertions
* of text at pos.limit. Upon return,
* pos.start should be in the range
* [originalStart, pos.limit).
* pos.start should be positioned such that
* characters [originalStart,
* pos.start) will not be changed in the future by this
* transliterator and characters [pos.start,
* pos.limit) are unchanged.Implementations of this method should also obey the * following invariants:
* *pos.limit and pos.contextLimit
* should be updated to reflect changes in length of the text
* between pos.start and pos.limit. The
* difference pos.contextLimit - pos.limit should
* not change.pos.contextStart should not change.pos.start nor
* pos.limit should be less than
* originalStart.originalStart and text after
* pos.limit should not change.pos.contextStart and text after
* pos.contextLimit should be ignored.Subclasses may safely assume that all characters in
* [pos.start, pos.limit) are filtered.
* In other words, the filter has already been applied by the time
* this method is called. See
* filteredTransliterate().
*
*
This method is not for public consumption. Calling
* this method directly will transliterate
* [pos.start, pos.limit) without
* applying the filter. End user code should call
* transliterate() instead of this method. Subclass code
* should call filteredTransliterate() instead of
* this method.
*
* @param text the buffer holding transliterated and
* untransliterated text
*
* @param pos the indices indicating the start, limit, context
* start, and context limit of the text.
*
* @param incremental if true, assume more text may be inserted at
* pos.limit and act accordingly. Otherwise,
* transliterate all text between pos.start and
* pos.limit and move pos.start up to
* pos.limit.
*
* @see #transliterate
*/
virtual void handleTransliterate(Replaceable& text,
UTransPosition& pos,
UBool incremental) const = 0;
/**
* Transliterate a substring of text, as specified by index, taking filters
* into account. This method is for subclasses that need to delegate to
* another transliterator, such as CompoundTransliterator.
* @param text the text to be transliterated
* @param index the position indices
* @param incremental if TRUE, then assume more characters may be inserted
* at index.limit, and postpone processing to accomodate future incoming
* characters
*/
virtual void filteredTransliterate(Replaceable& text,
UTransPosition& index,
UBool incremental) const;
friend class CompoundTransliterator; // for filteredTransliterate()
friend class AnyTransliterator; // for filteredTransliterate()
private:
/**
* Top-level transliteration method, handling filtering, incremental and
* non-incremental transliteration, and rollback. All transliteration
* public API methods eventually call this method with a rollback argument
* of TRUE. Other entities may call this method but rollback should be
* FALSE.
*
*
If this transliterator has a filter, break up the input text into runs
* of unfiltered characters. Pass each run to
* In incremental mode, if rollback is TRUE, perform a special
* incremental procedure in which several passes are made over the input
* text, adding one character at a time, and committing successful
* transliterations as they occur. Unsuccessful transliterations are rolled
* back and retried with additional characters to give correct results.
*
* @param text the text to be transliterated
* @param index the position indices
* @param incremental if TRUE, then assume more characters may be inserted
* at index.limit, and postpone processing to accomodate future incoming
* characters
* @param rollback if TRUE and if incremental is TRUE, then perform special
* incremental processing, as described above, and undo partial
* transliterations where necessary. If incremental is FALSE then this
* parameter is ignored.
*/
virtual void filteredTransliterate(Replaceable& text,
UTransPosition& index,
UBool incremental,
UBool rollback) const;
public:
/**
* Returns the length of the longest context required by this transliterator.
* This is preceding context. The default implementation supplied
* by If no localized names exist in the system resource bundles,
* a name is synthesized using a localized
* Callers must take care if a transliterator is in use by
* multiple threads. The filter should not be changed by one
* thread while another thread may be transliterating.
*
* @deprecated This method will be made NON-VIRTUAL in Aug 2002.
*/
virtual void adoptFilter(UnicodeFilter* adoptedFilter);
#else
/**
* Changes the filter used by this transliterator. If the filter
* is set to null then no filtering will occur.
*
* Callers must take care if a transliterator is in use by
* multiple threads. The filter should not be changed by one
* thread while another thread may be transliterating.
* @param adoptedFilter the new filter to be adopted.
* @draft ICU 2.0
*/
void adoptFilter(UnicodeFilter* adoptedFilter);
#endif
/**
* Returns this transliterator's inverse. See the class
* documentation for details. This implementation simply inverts
* the two entities in the ID and attempts to retrieve the
* resulting transliterator. That is, if Subclasses with knowledge of their inverse may wish to
* override this method.
*
* @param status Output param to filled in with a success or an error.
* @return a transliterator that is an inverse, not necessarily
* exact, of this transliterator, or The relationship is symmetrical; registering (a, b) is
* equivalent to registering (b, a).
*
* The relevant IDs must still be registered separately as
* factories or classes.
*
* Only the targets are specified. Special inverses always
* have the form Any-Target1 <=> Any-Target2. The target should
* have canonical casing (the casing desired to be produced when
* an inverse is formed) and should contain no whitespace or other
* extraneous characters.
*
* @param target the target against which to register the inverse
* @param inverseTarget the inverse of target, that is
* Any-target.getInverse() => Any-inverseTarget
* @param bidirectional if true, register the reverse relation
* as well, that is, Any-inverseTarget.getInverse() => Any-target
* @internal
*/
static void _registerSpecialInverse(const UnicodeString& target,
const UnicodeString& inverseTarget,
UBool bidirectional);
public:
/**
* Unregisters a transliterator or class. This may be either
* a system transliterator or a user transliterator or class.
* Any attempt to construct an unregistered transliterator based
* on its ID will fail.
*
* @param ID the ID of the transliterator or class
* @return the Concrete subclasses of Transliterator that wish clients to
* be able to identify them should implement getDynamicClassID()
* and also a static method and data member:
*
* This method does not take filtering into account. The
* returned transliterator will have no filter.
*
* Subclasses with knowledge of their inverse may wish to
* override this method.
*
* @return a transliterator that is an inverse, not necessarily
* exact, of this transliterator, or Note: Most subclasses that implement
* handleTransliterator() will not want to use this
* method, since characters they see are already filtered. Only
* subclasses with special requirements, such as those overriding
* filteredTransliterate(), should need this method.
*
* @deprecated the new architecture provides filtering at the top
* level. This method will be removed Aug 2002.
*/
UChar filteredCharAt(const Replaceable& text, int32_t i) const;
#endif
};
inline int32_t Transliterator::getMaximumContextLength(void) const {
return maximumContextLength;
}
inline void Transliterator::setID(const UnicodeString& id) {
ID = id;
}
inline Transliterator::Token Transliterator::integerToken(int32_t i) {
Token t;
t.integer = i;
return t;
}
inline Transliterator::Token Transliterator::pointerToken(void* p) {
Token t;
t.pointer = p;
return t;
}
/**
* Definitions for deprecated API
* @deprecated Remove after Aug 2002
*/
#ifdef U_USE_DEPRECATED_TRANSLITERATOR_API
inline Transliterator* Transliterator::createInstance(const UnicodeString& ID,
UTransDirection dir,
UParseError* parseError){
UErrorCode status = U_ZERO_ERROR;
UParseError error;
if(parseError == NULL){
parseError = &error;
}
return Transliterator::createInstance(ID,dir,*parseError,status);
}
inline Transliterator* Transliterator::createInverse() const{
UErrorCode status = U_ZERO_ERROR;
return createInverse(status);
}
#endif
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_TRANSLITERATION */
#endif
Transliterator returns zero; subclasses
* that use preceding context should override this method to return the
* correct value. For example, if a transliterator translates "ddd" (where
* d is any digit) to "555" when preceded by "(ddd)", then the preceding
* context length is 5, the length of "(ddd)".
*
* @return The maximum number of preceding context characters this
* transliterator needs to examine
* @stable
*/
int32_t getMaximumContextLength(void) const;
protected:
/**
* Method for subclasses to use to set the maximum context length.
* @param maxContextLength the new value to be set.
* @see #getMaximumContextLength
*/
void setMaximumContextLength(int32_t maxContextLength);
public:
/**
* Returns a programmatic identifier for this transliterator.
* If this identifier is passed to createInstance(), it
* will return this object, if it has been registered.
* @return a programmatic identifier for this transliterator.
* @see #registerInstance
* @see #registerClass
* @see #getAvailableIDs
* @stable
*/
virtual const UnicodeString& getID(void) const;
/**
* Returns a name for this transliterator that is appropriate for
* display to the user in the default locale. See {@link
* #getDisplayName()} for details.
* @param ID the string identifier for this transliterator
* @param result Output param to receive the display name
* @return A reference to 'result'.
* @stable
*/
static UnicodeString& getDisplayName(const UnicodeString& ID,
UnicodeString& result);
/**
* Returns a name for this transliterator that is appropriate for
* display to the user in the given locale. This name is taken
* from the locale resource data in the standard manner of the
* java.text package.
*
* MessageFormat pattern from the resource data. The
* arguments to this pattern are an integer followed by one or two
* strings. The integer is the number of strings, either 1 or 2.
* The strings are formed by splitting the ID for this
* transliterator at the first '-'. If there is no '-', then the
* entire ID forms the only string.
* @param ID the string identifier for this transliterator
* @param inLocale the Locale in which the display name should be
* localized.
* @param result Output param to receive the display name
* @return A reference to 'result'.
* @stable
*/
static UnicodeString& getDisplayName(const UnicodeString& ID,
const Locale& inLocale,
UnicodeString& result);
/**
* Returns the filter used by this transliterator, or NULL
* if this transliterator uses no filter.
* @return the filter used by this transliterator, or NULL
* if this transliterator uses no filter.
* @stable
*/
const UnicodeFilter* getFilter(void) const;
/**
* Returns the filter used by this transliterator, or NULL if this
* transliterator uses no filter. The caller must eventually delete the
* result. After this call, this transliterator's filter is set to
* NULL.
* @return the filter used by this transliterator, or NULL if this
* transliterator uses no filter.
*/
UnicodeFilter* orphanFilter(void);
#ifdef U_USE_DEPRECATED_TRANSLITERATOR_API
/**
* Changes the filter used by this transliterator. If the filter
* is set to null then no filtering will occur.
*
* getID()
* returns "A-B", then this method will return the result of
* createInstance("B-A"), or null if that
* call fails.
*
* null if no such
* transliterator is registered.
* @see #registerInstance
* @stable
*/
Transliterator* createInverse(UErrorCode& status) const;
/**
* Returns a Transliterator object given its ID.
* The ID must be either a system transliterator ID or a ID registered
* using registerInstance().
*
* @param ID a valid ID, as enumerated by getAvailableIDs()
* @param dir either FORWARD or REVERSE.
* @param parseError Struct to recieve information on position
* of error if an error is encountered
* @param status Output param to filled in with a success or an error.
* @return A Transliterator object with the given ID
* @see #registerInstance
* @see #getAvailableIDs
* @see #getID
* @draft ICU 2.0
*/
static Transliterator* createInstance(const UnicodeString& ID,
UTransDirection dir,
UParseError& parseError,
UErrorCode& status);
/**
* Returns a Transliterator object given its ID.
* The ID must be either a system transliterator ID or a ID registered
* using registerInstance().
* @param ID a valid ID, as enumerated by getAvailableIDs()
* @param dir either FORWARD or REVERSE.
* @param status Output param to filled in with a success or an error.
* @return A Transliterator object with the given ID
* @draft ICU 2.0
*/
static Transliterator* createInstance(const UnicodeString& ID,
UTransDirection dir,
UErrorCode& status);
/**
* Returns a Transliterator object constructed from
* the given rule string. This will be a RuleBasedTransliterator,
* if the rule string contains only rules, or a
* CompoundTransliterator, if it contains ID blocks, or a
* NullTransliterator, if it contains ID blocks which parse as
* empty for the given direction.
* @param id the id for the transliterator.
* @param rules rules, separated by ';'
* @param dir either FORWARD or REVERSE.
* @param parseError Struct to recieve information on position
* of error if an error is encountered
* @param status Output param set to success/failure code.
* @draft ICU 2.0
*/
static Transliterator* createFromRules(const UnicodeString& ID,
const UnicodeString& rules,
UTransDirection dir,
UParseError& parseError,
UErrorCode& status);
/**
* Create a rule string that can be passed to createFromRules()
* to recreate this transliterator.
* @param result the string to receive the rules. Previous
* contents will be deleted.
* @param escapeUnprintable if TRUE then convert unprintable
* character to their hex escape representations, \uxxxx or
* \Uxxxxxxxx. Unprintable characters are those other than
* U+000A, U+0020..U+007E.
* @draft ICU 2.0
*/
virtual UnicodeString& toRules(UnicodeString& result,
UBool escapeUnprintable) const;
/**
* Returns the set of all characters that may be modified in the
* input text by this Transliterator. This incorporates this
* object's current filter; if the filter is changed, the return
* value of this function will change. The default implementation
* returns an empty set. Some subclasses may override {@link
* #handleGetSourceSet()} to return a more precise result. The
* return result is approximate in any case and is intended for
* use by tests, tools, or utilities.
* @param result receives result set; previous contents lost
* @return a reference to result
* @see #getTargetSet
* @see #handleGetSourceSet
*/
UnicodeSet& getSourceSet(UnicodeSet& result) const;
/**
* Framework method that returns the set of all characters that
* may be modified in the input text by this Transliterator,
* ignoring the effect of this object's filter. The base class
* implementation returns the empty set. Subclasses that wish to
* implement this should override this method.
* @return the set of characters that this transliterator may
* modify. The set may be modified, so subclasses should return a
* newly-created object.
* @param result receives result set; previous contents lost
* @see #getSourceSet
* @see #getTargetSet
*/
virtual void handleGetSourceSet(UnicodeSet& result) const;
/**
* Returns the set of all characters that may be generated as
* replacement text by this transliterator. The default
* implementation returns the empty set. Some subclasses may
* override this method to return a more precise result. The
* return result is approximate in any case and is intended for
* use by tests, tools, or utilities requiring such
* meta-information.
* @param result receives result set; previous contents lost
* @return a reference to result
* @see #getTargetSet
*/
virtual UnicodeSet& getTargetSet(UnicodeSet& result) const;
public:
/**
* Registers a factory function that creates transliterators of
* a given ID.
* @param id the ID being registered
* @param factory a function pointer that will be copied and
* called later when the given ID is passed to createInstance()
* @param context a context pointer that will be stored and
* later passed to the factory function when an ID matching
* the registration ID is being instantiated with this factory.
* @draft ICU 2.0
*/
static void registerFactory(const UnicodeString& id,
Factory factory,
Token context);
/**
* Registers a instance obj of a subclass of
* Transliterator with the system. When
* createInstance() is called with an ID string that is
* equal to obj->getID(), then obj->clone() is
* returned.
*
* After this call the Transliterator class owns the adoptedObj
* and will delete it.
*
* @param adoptedObj an instance of subclass of
* Transliterator that defines clone()
* @see #createInstance
* @see #registerClass
* @see #unregister
* @stable
*/
static void registerInstance(Transliterator* adoptedObj);
protected:
/**
* @internal
* @param id the ID being registered
* @param factory a function pointer that will be copied and
* called later when the given ID is passed to createInstance()
* @param context a context pointer that will be stored and
* later passed to the factory function when an ID matching
* the registration ID is being instantiated with this factory.
*/
static void _registerFactory(const UnicodeString& id,
Factory factory,
Token context);
/**
* @internal
*/
static void _registerInstance(Transliterator* adoptedObj);
/**
* Register two targets as being inverses of one another. For
* example, calling registerSpecialInverse("NFC", "NFD", true) causes
* Transliterator to form the following inverse relationships:
*
* NFC => NFD
* Any-NFC => Any-NFD
* NFD => NFC
* Any-NFD => Any-NFC
*
* (Without the special inverse registration, the inverse of NFC
* would be NFC-Any.) Note that NFD is shorthand for Any-NFD, but
* that the presence or absence of "Any-" is preserved.
*
* Object that was registered with
* ID, or null if none was
* @see #registerInstance
* @see #registerClass
* @stable
*/
static void unregister(const UnicodeString& ID);
public:
/**
* Return the number of IDs currently registered with the system.
* To retrieve the actual IDs, call getAvailableID(i) with
* i from 0 to countAvailableIDs() - 1.
* @return the number of IDs currently registered with the system.
* @stable
*/
static int32_t countAvailableIDs(void);
/**
* Return the index-th available ID. index must be between 0
* and countAvailableIDs() - 1, inclusive. If index is out of
* range, the result of getAvailableID(0) is returned.
* @param index the given ID index.
* @return the index-th available ID. index must be between 0
* and countAvailableIDs() - 1, inclusive. If index is out of
* range, the result of getAvailableID(0) is returned.
* @stable
*/
static const UnicodeString& getAvailableID(int32_t index);
/**
* Return the number of registered source specifiers.
* @return the number of registered source specifiers.
* @draft ICU 2.0
*/
static int32_t countAvailableSources(void);
/**
* Return a registered source specifier.
* @param index which specifier to return, from 0 to n-1, where
* n = countAvailableSources()
* @param result fill-in paramter to receive the source specifier.
* If index is out of range, result will be empty.
* @return reference to result
* @draft ICU 2.0
*/
static UnicodeString& getAvailableSource(int32_t index,
UnicodeString& result);
/**
* Return the number of registered target specifiers for a given
* source specifier.
* @param source the given source specifier.
* @return the number of registered target specifiers for a given
* source specifier.
* @draft ICU 2.0
*/
static int32_t countAvailableTargets(const UnicodeString& source);
/**
* Return a registered target specifier for a given source.
* @param index which specifier to return, from 0 to n-1, where
* n = countAvailableTargets(source)
* @param source the source specifier
* @param result fill-in paramter to receive the target specifier.
* If source is invalid or if index is out of range, result will
* be empty.
* @return reference to result
* @draft ICU 2.0
*/
static UnicodeString& getAvailableTarget(int32_t index,
const UnicodeString& source,
UnicodeString& result);
/**
* Return the number of registered variant specifiers for a given
* source-target pair.
* @param source the source specifiers.
* @param target the target specifiers.
* @draft ICU 2.0
*/
static int32_t countAvailableVariants(const UnicodeString& source,
const UnicodeString& target);
/**
* Return a registered variant specifier for a given source-target
* pair.
* @param index which specifier to return, from 0 to n-1, where
* n = countAvailableVariants(source, target)
* @param source the source specifier
* @param target the target specifier
* @param result fill-in paramter to receive the variant
* specifier. If source is invalid or if target is invalid or if
* index is out of range, result will be empty.
* @return reference to result
* @draft ICU 2.0
*/
static UnicodeString& getAvailableVariant(int32_t index,
const UnicodeString& source,
const UnicodeString& target,
UnicodeString& result);
protected:
/**
* Non-mutexed internal method
* @internal
*/
static int32_t _countAvailableSources(void);
/**
* Non-mutexed internal method
* @internal
*/
static UnicodeString& _getAvailableSource(int32_t index,
UnicodeString& result);
/**
* Non-mutexed internal method
* @internal
*/
static int32_t _countAvailableTargets(const UnicodeString& source);
/**
* Non-mutexed internal method
* @internal
*/
static UnicodeString& _getAvailableTarget(int32_t index,
const UnicodeString& source,
UnicodeString& result);
/**
* Non-mutexed internal method
* @internal
*/
static int32_t _countAvailableVariants(const UnicodeString& source,
const UnicodeString& target);
/**
* Non-mutexed internal method
* @internal
*/
static UnicodeString& _getAvailableVariant(int32_t index,
const UnicodeString& source,
const UnicodeString& target,
UnicodeString& result);
public:
/**
* Return the class ID for this class. This is useful only for
* comparing to a return value from getDynamicClassID(). For example:
*
* . Base* polymorphic_pointer = createPolymorphicObject();
* . if (polymorphic_pointer->getDynamicClassID() ==
* . Derived::getStaticClassID()) ...
*
* @return The class ID for all objects of this class.
* @draft ICU 2.0
*/
static UClassID getStaticClassID(void) { return (UClassID)&fgClassID; }
/**
* Returns a unique class ID polymorphically. This method
* is to implement a simple version of RTTI, since not all C++
* compilers support genuine RTTI. Polymorphic operator==() and
* clone() methods call this method.
*
*
* static UClassID getStaticClassID() { return (UClassID)&fgClassID; }
* static char fgClassID;
*
*
* Subclasses that do not implement this method will have a
* dynamic class ID of Transliterator::getStatisClassID().
*
* @return The class ID for this object. All objects of a given
* class have the same class ID. Objects of other classes have
* different class IDs.
* @draft ICU 2.0
*/
virtual UClassID getDynamicClassID(void) const { return getStaticClassID(); };
private:
/**
* Class identifier for subclasses of Transliterator that do not
* define their class (anonymous subclasses).
*/
static const char fgClassID;
protected:
/**
* Set the ID of this transliterators. Subclasses shouldn't do
* this, unless the underlying script behavior has changed.
* @param id the new id t to be set.
*/
void setID(const UnicodeString& id);
private:
static void initializeRegistry(void);
#ifdef U_USE_DEPRECATED_TRANSLITERATOR_API
public:
/**
* Returns a Transliterator object given its ID.
* The ID must be either a system transliterator ID or a ID registered
* using registerInstance().
*
* @param ID a valid ID, as enumerated by getAvailableIDs()
* @param dir either FORWARD or REVERSE.
* @param parseError Struct to recieve information on position
* @return A Transliterator object with the given ID
* @exception IllegalArgumentException if the given ID is invalid.
* @see #registerInstance
* @see #getAvailableIDs
* @see #getID
* @deprecated Remove after Aug 2002 use factory mehod that takes UParseError
* and UErrorCode
*/
inline Transliterator* createInstance(const UnicodeString& ID,
UTransDirection dir=UTRANS_FORWARD,
UParseError* parseError=0);
/**
* Returns this transliterator's inverse. See the class
* documentation for details. This implementation simply inverts
* the two entities in the ID and attempts to retrieve the
* resulting transliterator. That is, if getID()
* returns "A-B", then this method will return the result of
* createInstance("B-A"), or null if that
* call fails.
*
* null if no such
* transliterator is registered.
* @deprecated Remove after Aug 2002 use factory mehod that takes UErrorCode
*/
inline Transliterator* createInverse() const;
protected:
/**
* Method for subclasses to use to obtain a character in the given
* string, with filtering. If the character at the given offset
* is excluded by this transliterator's filter, then U+FFFE is returned.
*
*