/* ********************************************************************** * Copyright (C) 1999-2011, International Business Machines * Corporation and others. All Rights Reserved. ********************************************************************** * Date Name Description * 11/17/99 aliu Creation. ********************************************************************** */ #ifndef TRANSLIT_H #define TRANSLIT_H #include "unicode/utypes.h" /** * \file * \brief C++ API: Tranforms text from one format to another. */ #if !UCONFIG_NO_TRANSLITERATION #include "unicode/uobject.h" #include "unicode/unistr.h" #include "unicode/parseerr.h" #include "unicode/utrans.h" // UTransPosition, UTransDirection #include "unicode/strenum.h" U_NAMESPACE_BEGIN class UnicodeFilter; class UnicodeSet; class CompoundTransliterator; class TransliteratorParser; class NormalizationTransliterator; class TransliteratorIDParser; /** * * <code>Transliterator</code> 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 <em>translate</em> Russian to English! * Transliteration, unlike translation, operates on characters, without * reference to the meanings of words and sentences. * * <p>Although script conversion is its most common use, a * transliterator can actually perform a more general class of tasks. * In fact, <code>Transliterator</code> 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 <code>Transliterator</code>. * * <p><b>Transliterators are stateless</b> * * <p><code>Transliterator</code> objects are <em>stateless</em>; they * retain no information between calls to * <code>transliterate()</code>. (However, this does <em>not</em> * mean that threads may share transliterators without synchronizing * them. Transliterators are not immutable, so they must be * synchronized when shared between threads.) This 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 * <code>Transliterator</code> objects are stateless, the source text * itself embodies all the needed information, and delayed operation * allows arbitrary complexity. * * <p><b>Batch transliteration</b> * * <p>The simplest way to perform transliteration is all at once, on a * string of existing text. This is referred to as <em>batch</em> * transliteration. For example, given a string <code>input</code> * and a transliterator <code>t</code>, the call * * \htmlonly<blockquote>\endhtmlonly<code>String result = t.transliterate(input); * </code>\htmlonly</blockquote>\endhtmlonly * * will transliterate it and return the result. Other methods allow * the client to specify a substring to be transliterated and to use * {@link Replaceable } objects instead of strings, in order to * preserve out-of-band information (such as text styles). * * <p><b>Keyboard transliteration</b> * * <p>Somewhat more involved is <em>keyboard</em>, 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. * * <p>In keyboard transliteration, a <code>Replaceable</code> 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. * * <p>Consider the simple <code>RuleBasedTransliterator</code>: * * \htmlonly<blockquote>\endhtmlonly<code> * th>{theta}<br> * t>{tau} * </code>\htmlonly</blockquote>\endhtmlonly * * When the user types 't', nothing will happen, since the * transliterator is waiting to see if the next character is 'h'. To * remedy this, we introduce the notion of a cursor, marked by a '|' * in the output string: * * \htmlonly<blockquote>\endhtmlonly<code> * t>|{tau}<br> * {tau}h>{theta} * </code>\htmlonly</blockquote>\endhtmlonly * * Now when the user types 't', tau appears, and if the next character * is 'h', the tau changes to a theta. This is accomplished by * maintaining a cursor position (independent of the insertion point, * and invisible in the GUI) across calls to * <code>transliterate()</code>. Typically, the cursor will * be coincident with the insertion point, but in a case like the one * above, it will precede the insertion point. * * <p>Keyboard transliteration methods maintain a set of three indices * that are updated with each call to * <code>transliterate()</code>, including the cursor, start, * and limit. Since these indices are changed by the method, they are * passed in an <code>int[]</code> array. The <code>START</code> 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 <code>CURSOR</code>). The * <code>CURSOR</code> 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 <code>CURSOR</code> can also be * explicitly set by rules in a <code>RuleBasedTransliterator</code>. * Any characters before the <code>CURSOR</code> index are frozen; * future keyboard transliteration calls within this input sequence * will not change them. New text is inserted at the * <code>LIMIT</code> index, which marks the end of the substring that * the transliterator looks at. * * <p>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 * <code>finishTransliteration()</code> to complete any * pending transliterations. * * <p><b>Inverses</b> * * <p>Pairs of transliterators may be inverses of one another. For * example, if transliterator <b>A</b> transliterates characters by * incrementing their Unicode value (so "abc" -> "def"), and * transliterator <b>B</b> decrements character values, then <b>A</b> * is an inverse of <b>B</b> and vice versa. If we compose <b>A</b> * with <b>B</b> in a compound transliterator, the result is the * indentity transliterator, that is, a transliterator that does not * change its input text. * * The <code>Transliterator</code> method <code>getInverse()</code> * returns a transliterator's inverse, if one exists, or * <code>null</code> otherwise. However, the result of * <code>getInverse()</code> usually will <em>not</em> be a true * mathematical inverse. This is because true inverse transliterators * are difficult to formulate. For example, consider two * transliterators: <b>AB</b>, which transliterates the character 'A' * to 'B', and <b>BA</b>, which transliterates 'B' to 'A'. It might * seem that these are exact inverses, since * * \htmlonly<blockquote>\endhtmlonly"A" x <b>AB</b> -> "B"<br> * "B" x <b>BA</b> -> "A"\htmlonly</blockquote>\endhtmlonly * * where 'x' represents transliteration. However, * * \htmlonly<blockquote>\endhtmlonly"ABCD" x <b>AB</b> -> "BBCD"<br> * "BBCD" x <b>BA</b> -> "AACD"\htmlonly</blockquote>\endhtmlonly * * so <b>AB</b> composed with <b>BA</b> is not the * identity. Nonetheless, <b>BA</b> may be usefully considered to be * <b>AB</b>'s inverse, and it is on this basis that * <b>AB</b><code>.getInverse()</code> could legitimately return * <b>BA</b>. * * <p><b>IDs and display names</b> * * <p>A transliterator is designated by a short identifier string or * <em>ID</em>. IDs follow the format <em>source-destination</em>, * where <em>source</em> describes the entity being replaced, and * <em>destination</em> describes the entity replacing * <em>source</em>. 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. * * <p>In addition to programmatic IDs, transliterator objects have * display names for presentation in user interfaces, returned by * {@link #getDisplayName }. * * <p><b>Factory methods and registration</b> * * <p>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 * <code>getAvailableIDs()</code>. Since transliterators are mutable, * multiple calls to {@link #createInstance } with the same ID will * return distinct objects. * * <p>In addition to the system transliterators registered at startup, * user transliterators may be registered by calling * <code>registerInstance()</code> 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 <tt>registerInstance()</tt> must implement * <tt>clone()</tt> propertly. To register a transliterator subclass * without instantiating it (until it is needed), users may call * {@link #registerFactory }. In this case, the objects are * instantiated by invoking the zero-argument public constructor of * the class. * * <p><b>Subclassing</b> * * Subclasses must implement the abstract method * <code>handleTransliterate()</code>. <p>Subclasses should override * the <code>transliterate()</code> method taking a * <code>Replaceable</code> and the <code>transliterate()</code> * method taking a <code>String</code> and <code>StringBuffer</code> * if the performance of these methods can be improved over the * performance obtained by the default implementations in this class. * * @author Alan Liu * @stable ICU 2.0 */ class U_I18N_API Transliterator : public UObject { private: /** * Programmatic name, e.g., "Latin-Arabic". */ UnicodeString ID; /** * This transliterator's filter. Any character for which * <tt>filter.contains()</tt> returns <tt>false</tt> will not be * altered by this transliterator. If <tt>filter</tt> is * <tt>null</tt> then no filtering is applied. */ UnicodeFilter* filter; int32_t maximumContextLength; public: /** * A context integer or pointer for a factory function, passed by * value. * @stable ICU 2.4 */ union Token { /** * This token, interpreted as a 32-bit integer. * @stable ICU 2.4 */ int32_t integer; /** * This token, interpreted as a native pointer. * @stable ICU 2.4 */ void* pointer; }; #ifndef U_HIDE_INTERNAL_API /** * Return a token containing an integer. * @return a token containing an integer. * @internal */ inline static Token integerToken(int32_t); /** * Return a token containing a pointer. * @return a token containing a pointer. * @internal */ inline static Token pointerToken(void*); #endif /* U_HIDE_INTERNAL_API */ /** * 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. * @stable ICU 2.4 */ typedef Transliterator* (U_EXPORT2 *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 * <tt>filter.contains()</tt> returns <tt>false</tt> will not be * altered by this transliterator. If <tt>filter</tt> is * <tt>null</tt> then no filtering is applied. * @stable ICU 2.4 */ Transliterator(const UnicodeString& ID, UnicodeFilter* adoptedFilter); /** * Copy constructor. * @stable ICU 2.4 */ Transliterator(const Transliterator&); /** * Assignment operator. * @stable ICU 2.4 */ 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. * @stable ICU 2.4 */ static Transliterator* createBasicInstance(const UnicodeString& id, const UnicodeString* canon); friend class TransliteratorParser; // for parseID() friend class TransliteratorIDParser; // for createBasicInstance() friend class TransliteratorAlias; // for setID() public: /** * Destructor. * @stable ICU 2.0 */ 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 <tt>registerInstance()</tt> * 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 ICU 2.0 */ virtual Transliterator* clone() const; /** * Transliterates a segment of a string, with optional filtering. * * @param text the string to be transliterated * @param start the beginning index, inclusive; <code>0 <= start * <= limit</code>. * @param limit the ending index, exclusive; <code>start <= limit * <= text.length()</code>. * @return The new limit index. The text previously occupying <code>[start, * limit)</code> has been transliterated, possibly to a string of a different * length, at <code>[start, </code><em>new-limit</em><code>)</code>, where * <em>new-limit</em> is the return value. If the input offsets are out of bounds, * the returned value is -1 and the input string remains unchanged. * @stable ICU 2.0 */ 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 ICU 2.0 */ 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 * <code>insertion</code> will be inserted into <code>text</code> * at <code>index.limit</code>, advancing * <code>index.limit</code> by <code>insertion.length()</code>. * Then the transliterator will try to transliterate characters of * <code>text</code> between <code>index.cursor</code> and * <code>index.limit</code>. Characters before * <code>index.cursor</code> will not be changed. * * <p>Upon return, values in <code>index</code> will be updated. * <code>index.start</code> will be advanced to the first * character that future calls to this method will read. * <code>index.cursor</code> and <code>index.limit</code> will * be adjusted to delimit the range of text that future calls to * this method may change. * * <p>Typical usage of this method begins with an initial call * with <code>index.start</code> and <code>index.limit</code> * set to indicate the portion of <code>text</code> to be * transliterated, and <code>index.cursor == index.start</code>. * Thereafter, <code>index</code> can be used without * modification in future calls, provided that all changes to * <code>text</code> are made via this method. * * <p>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. * * <ul><li><code>index.start</code>: the beginning index, * inclusive; <code>0 <= index.start <= index.limit</code>. * * <li><code>index.limit</code>: the ending index, exclusive; * <code>index.start <= index.limit <= text.length()</code>. * <code>insertion</code> is inserted at * <code>index.limit</code>. * * <li><code>index.cursor</code>: the next character to be * considered for transliteration; <code>index.start <= * index.cursor <= index.limit</code>. Characters before * <code>index.cursor</code> will not be changed by future calls * to this method.</ul> * * @param insertion text to be inserted and possibly * transliterated into the translation buffer at * <code>index.limit</code>. If <code>null</code> then no text * is inserted. * @param status Output param to filled in with a success or an error. * @see #handleTransliterate * @exception IllegalArgumentException if <code>index</code> * is invalid * @see UTransPosition * @stable ICU 2.0 */ 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. * @param text the buffer holding transliterated and * untransliterated text * @param index an array of three integers. * @param insertion text to be inserted and possibly * transliterated into the translation buffer at * <code>index.limit</code>. * @param status Output param to filled in with a success or an error. * @see #transliterate(Replaceable&, UTransPosition&, const UnicodeString&, UErrorCode&) const * @stable ICU 2.0 */ 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&, const UnicodeString&, UErrorCode&) const } * for details. * @param text the buffer holding transliterated and * untransliterated text * @param index an array of three integers. See {@link * #transliterate(Replaceable&, UTransPosition&, const UnicodeString&, UErrorCode&) const }. * @param status Output param to filled in with a success or an error. * @see #transliterate(Replaceable, int[], String) * @stable ICU 2.0 */ 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 * <code>transliterate()</code>. * @param text the buffer holding transliterated and * untransliterated text. * @param index the array of indices previously passed to {@link * #transliterate } * @stable ICU 2.0 */ 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 * <code>index.limit</code>. * @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 * <code>originalStart</code> refer to the value of * <code>pos.start</code> upon entry. * * <ul> * <li>If <code>incremental</code> is false, then this method * should transliterate all characters between * <code>pos.start</code> and <code>pos.limit</code>. Upon return * <code>pos.start</code> must == <code> pos.limit</code>.</li> * * <li>If <code>incremental</code> is true, then this method * should transliterate all characters between * <code>pos.start</code> and <code>pos.limit</code> that can be * unambiguously transliterated, regardless of future insertions * of text at <code>pos.limit</code>. Upon return, * <code>pos.start</code> should be in the range * [<code>originalStart</code>, <code>pos.limit</code>). * <code>pos.start</code> should be positioned such that * characters [<code>originalStart</code>, <code> * pos.start</code>) will not be changed in the future by this * transliterator and characters [<code>pos.start</code>, * <code>pos.limit</code>) are unchanged.</li> * </ul> * * <p>Implementations of this method should also obey the * following invariants:</p> * * <ul> * <li> <code>pos.limit</code> and <code>pos.contextLimit</code> * should be updated to reflect changes in length of the text * between <code>pos.start</code> and <code>pos.limit</code>. The * difference <code> pos.contextLimit - pos.limit</code> should * not change.</li> * * <li><code>pos.contextStart</code> should not change.</li> * * <li>Upon return, neither <code>pos.start</code> nor * <code>pos.limit</code> should be less than * <code>originalStart</code>.</li> * * <li>Text before <code>originalStart</code> and text after * <code>pos.limit</code> should not change.</li> * * <li>Text before <code>pos.contextStart</code> and text after * <code> pos.contextLimit</code> should be ignored.</li> * </ul> * * <p>Subclasses may safely assume that all characters in * [<code>pos.start</code>, <code>pos.limit</code>) are filtered. * In other words, the filter has already been applied by the time * this method is called. See * <code>filteredTransliterate()</code>. * * <p>This method is <b>not</b> for public consumption. Calling * this method directly will transliterate * [<code>pos.start</code>, <code>pos.limit</code>) without * applying the filter. End user code should call <code> * transliterate()</code> instead of this method. Subclass code * and wrapping transliterators should call * <code>filteredTransliterate()</code> instead of this method.<p> * * @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 * <code>pos.limit</code> and act accordingly. Otherwise, * transliterate all text between <code>pos.start</code> and * <code>pos.limit</code> and move <code>pos.start</code> up to * <code>pos.limit</code>. * * @see #transliterate * @stable ICU 2.4 */ virtual void handleTransliterate(Replaceable& text, UTransPosition& pos, UBool incremental) const = 0; public: /** * 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 * @stable ICU 2.4 */ virtual void filteredTransliterate(Replaceable& text, UTransPosition& index, UBool incremental) const; 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. * * <p>If this transliterator has a filter, break up the input text into runs * of unfiltered characters. Pass each run to * subclass.handleTransliterate(). * * <p>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 <em>preceding</em> context. The default implementation supplied * by <code>Transliterator</code> 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 ICU 2.0 */ 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 * @stable ICU 2.4 */ void setMaximumContextLength(int32_t maxContextLength); public: /** * Returns a programmatic identifier for this transliterator. * If this identifier is passed to <code>createInstance()</code>, it * will return this object, if it has been registered. * @return a programmatic identifier for this transliterator. * @see #registerInstance * @see #registerFactory * @see #getAvailableIDs * @stable ICU 2.0 */ 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 ICU 2.0 */ static UnicodeString& U_EXPORT2 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 * <code>java.text</code> package. * * <p>If no localized names exist in the system resource bundles, * a name is synthesized using a localized * <code>MessageFormat</code> 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 ICU 2.0 */ static UnicodeString& U_EXPORT2 getDisplayName(const UnicodeString& ID, const Locale& inLocale, UnicodeString& result); /** * Returns the filter used by this transliterator, or <tt>NULL</tt> * if this transliterator uses no filter. * @return the filter used by this transliterator, or <tt>NULL</tt> * if this transliterator uses no filter. * @stable ICU 2.0 */ const UnicodeFilter* getFilter(void) const; /** * Returns the filter used by this transliterator, or <tt>NULL</tt> if this * transliterator uses no filter. The caller must eventually delete the * result. After this call, this transliterator's filter is set to * <tt>NULL</tt>. * @return the filter used by this transliterator, or <tt>NULL</tt> if this * transliterator uses no filter. * @stable ICU 2.4 */ UnicodeFilter* orphanFilter(void); /** * Changes the filter used by this transliterator. If the filter * is set to <tt>null</tt> then no filtering will occur. * * <p>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. * @stable ICU 2.0 */ void adoptFilter(UnicodeFilter* adoptedFilter); /** * 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 <code>getID()</code> * returns "A-B", then this method will return the result of * <code>createInstance("B-A")</code>, or <code>null</code> if that * call fails. * * <p>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 <code>null</code> if no such * transliterator is registered. * @see #registerInstance * @stable ICU 2.0 */ Transliterator* createInverse(UErrorCode& status) const; /** * Returns a <code>Transliterator</code> object given its ID. * The ID must be either a system transliterator ID or a ID registered * using <code>registerInstance()</code>. * * @param ID a valid ID, as enumerated by <code>getAvailableIDs()</code> * @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 <code>Transliterator</code> object with the given ID * @see #registerInstance * @see #getAvailableIDs * @see #getID * @stable ICU 2.0 */ static Transliterator* U_EXPORT2 createInstance(const UnicodeString& ID, UTransDirection dir, UParseError& parseError, UErrorCode& status); /** * Returns a <code>Transliterator</code> object given its ID. * The ID must be either a system transliterator ID or a ID registered * using <code>registerInstance()</code>. * @param ID a valid ID, as enumerated by <code>getAvailableIDs()</code> * @param dir either FORWARD or REVERSE. * @param status Output param to filled in with a success or an error. * @return A <code>Transliterator</code> object with the given ID * @stable ICU 2.0 */ static Transliterator* U_EXPORT2 createInstance(const UnicodeString& ID, UTransDirection dir, UErrorCode& status); /** * Returns a <code>Transliterator</code> 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. * @stable ICU 2.0 */ static Transliterator* U_EXPORT2 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. * @stable ICU 2.0 */ virtual UnicodeString& toRules(UnicodeString& result, UBool escapeUnprintable) const; /** * Return the number of elements that make up this transliterator. * For example, if the transliterator "NFD;Jamo-Latin;Latin-Greek" * were created, the return value of this method would be 3. * * <p>If this transliterator is not composed of other * transliterators, then this method returns 1. * @return the number of transliterators that compose this * transliterator, or 1 if this transliterator is not composed of * multiple transliterators * @stable ICU 3.0 */ int32_t countElements() const; /** * Return an element that makes up this transliterator. For * example, if the transliterator "NFD;Jamo-Latin;Latin-Greek" * were created, the return value of this method would be one * of the three transliterator objects that make up that * transliterator: [NFD, Jamo-Latin, Latin-Greek]. * * <p>If this transliterator is not composed of other * transliterators, then this method will return a reference to * this transliterator when given the index 0. * @param index a value from 0..countElements()-1 indicating the * transliterator to return * @param ec input-output error code * @return one of the transliterators that makes up this * transliterator, if this transliterator is made up of multiple * transliterators, otherwise a reference to this object if given * an index of 0 * @stable ICU 3.0 */ const Transliterator& getElement(int32_t index, UErrorCode& ec) 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 * @stable ICU 2.4 */ 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 * @stable ICU 2.4 */ 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 * @stable ICU 2.4 */ 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. * @stable ICU 2.0 */ static void U_EXPORT2 registerFactory(const UnicodeString& id, Factory factory, Token context); /** * Registers an instance <tt>obj</tt> of a subclass of * <code>Transliterator</code> with the system. When * <tt>createInstance()</tt> is called with an ID string that is * equal to <tt>obj->getID()</tt>, then <tt>obj->clone()</tt> is * returned. * * After this call the Transliterator class owns the adoptedObj * and will delete it. * * @param adoptedObj an instance of subclass of * <code>Transliterator</code> that defines <tt>clone()</tt> * @see #createInstance * @see #registerFactory * @see #unregister * @stable ICU 2.0 */ static void U_EXPORT2 registerInstance(Transliterator* adoptedObj); /** * Registers an ID string as an alias of another ID string. * That is, after calling this function, <tt>createInstance(aliasID)</tt> * will return the same thing as <tt>createInstance(realID)</tt>. * This is generally used to create shorter, more mnemonic aliases * for long compound IDs. * * @param aliasID The new ID being registered. * @param realID The ID that the new ID is to be an alias for. * This can be a compound ID and can include filters and should * refer to transliterators that have already been registered with * the framework, although this isn't checked. * @stable ICU 3.6 */ static void U_EXPORT2 registerAlias(const UnicodeString& aliasID, const UnicodeString& realID); protected: #ifndef U_HIDE_INTERNAL_API /** * @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); /** * @internal */ static void _registerAlias(const UnicodeString& aliasID, const UnicodeString& realID); /** * Register two targets as being inverses of one another. For * example, calling registerSpecialInverse("NFC", "NFD", true) causes * Transliterator to form the following inverse relationships: * * <pre>NFC => NFD * Any-NFC => Any-NFD * NFD => NFC * Any-NFD => Any-NFC</pre> * * (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. * * <p>The relationship is symmetrical; registering (a, b) is * equivalent to registering (b, a). * * <p>The relevant IDs must still be registered separately as * factories or classes. * * <p>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); #endif /* U_HIDE_INTERNAL_API */ 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 <code>Object</code> that was registered with * <code>ID</code>, or <code>null</code> if none was * @see #registerInstance * @see #registerFactory * @stable ICU 2.0 */ static void U_EXPORT2 unregister(const UnicodeString& ID); public: /** * Return a StringEnumeration over the IDs available at the time of the * call, including user-registered IDs. * @param ec input-output error code * @return a newly-created StringEnumeration over the transliterators * available at the time of the call. The caller should delete this object * when done using it. * @stable ICU 3.0 */ static StringEnumeration* U_EXPORT2 getAvailableIDs(UErrorCode& ec); /** * Return the number of registered source specifiers. * @return the number of registered source specifiers. * @stable ICU 2.0 */ static int32_t U_EXPORT2 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 * @stable ICU 2.0 */ static UnicodeString& U_EXPORT2 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. * @stable ICU 2.0 */ static int32_t U_EXPORT2 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 * @stable ICU 2.0 */ static UnicodeString& U_EXPORT2 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. * @stable ICU 2.0 */ static int32_t U_EXPORT2 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 * @stable ICU 2.0 */ static UnicodeString& U_EXPORT2 getAvailableVariant(int32_t index, const UnicodeString& source, const UnicodeString& target, UnicodeString& result); protected: #ifndef U_HIDE_INTERNAL_API /** * 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); #endif /* U_HIDE_INTERNAL_API */ 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. * @stable ICU 2.4 */ void setID(const UnicodeString& id); public: /** * Return the class ID for this class. This is useful only for * comparing to a return value from getDynamicClassID(). * Note that Transliterator is an abstract base class, and therefor * no fully constructed object will have a dynamic * UCLassID that equals the UClassID returned from * TRansliterator::getStaticClassID(). * @return The class ID for class Transliterator. * @stable ICU 2.0 */ static UClassID U_EXPORT2 getStaticClassID(void); /** * Returns a unique class ID <b>polymorphically</b>. 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. * * <p>Concrete subclasses of Transliterator must use the * UOBJECT_DEFINE_RTTI_IMPLEMENTATION macro from * uobject.h to provide the RTTI functions. * * @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. * @stable ICU 2.0 */ virtual UClassID getDynamicClassID(void) const = 0; private: static UBool initializeRegistry(UErrorCode &status); public: #ifndef U_HIDE_OBSOLETE_API /** * 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. * @obsolete ICU 3.4 use getAvailableIDs() instead */ static int32_t U_EXPORT2 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. * @obsolete ICU 3.4 use getAvailableIDs() instead; this function * is not thread safe, since it returns a reference to storage that * may become invalid if another thread calls unregister */ static const UnicodeString& U_EXPORT2 getAvailableID(int32_t index); #endif /* U_HIDE_OBSOLETE_API */ }; inline int32_t Transliterator::getMaximumContextLength(void) const { return maximumContextLength; } inline void Transliterator::setID(const UnicodeString& id) { ID = id; // NUL-terminate the ID string, which is a non-aliased copy. ID.append((UChar)0); ID.truncate(ID.length()-1); } #ifndef U_HIDE_INTERNAL_API 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; } #endif U_NAMESPACE_END #endif /* #if !UCONFIG_NO_TRANSLITERATION */ #endif