// © 2016 and later: Unicode, Inc. and others. // License & terms of use: http://www.unicode.org/copyright.html /* ********************************************************************** * Copyright (C) 1999-2014, 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" #if U_SHOW_CPLUSPLUS_API /** * \file * \brief C++ API: Transforms 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 TransliteratorParser; class NormalizationTransliterator; class TransliteratorIDParser; /** * * 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.) 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 * 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); * * 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). * *

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 rule-based Transliterator: *

 *     th>{theta}
 *     t>{tau}
 * 
* * 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: *
 *     t>|{tau}
 *     {tau}h>{theta}
 * 
* * 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 * 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 rule-based Transliterator. * 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 * identity 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 * * \htmlonly

\endhtmlonly"A" x AB -> "B"
* "B" x BA -> "A"\htmlonly
\endhtmlonly * * where 'x' represents transliteration. However, * * \htmlonly
\endhtmlonly"ABCD" x AB -> "BBCD"
* "BBCD" x BA -> "AACD"\htmlonly
\endhtmlonly * * 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.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() properly. 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. * *

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. * *

Rule syntax * *

A set of rules determines how to perform translations. * Rules within a rule set are separated by semicolons (';'). * To include a literal semicolon, prefix it with a backslash ('\'). * Unicode Pattern_White_Space is ignored. * If the first non-blank character on a line is '#', * the entire line is ignored as a comment. * *

Each set of rules consists of two groups, one forward, and one * reverse. This is a convention that is not enforced; rules for one * direction may be omitted, with the result that translations in * that direction will not modify the source text. In addition, * bidirectional forward-reverse rules may be specified for * symmetrical transformations. * *

Note: Another description of the Transliterator rule syntax is available in * section * Transform Rules Syntax of UTS #35: Unicode LDML. * The rules are shown there using arrow symbols ← and → and ↔. * ICU supports both those and the equivalent ASCII symbols < and > and <>. * *

Rule statements take one of the following forms: * *

*
$alefmadda=\\u0622;
*
Variable definition. The name on the * left is assigned the text on the right. In this example, * after this statement, instances of the left hand name, * "$alefmadda", will be replaced by * the Unicode character U+0622. Variable names must begin * with a letter and consist only of letters, digits, and * underscores. Case is significant. Duplicate names cause * an exception to be thrown, that is, variables cannot be * redefined. The right hand side may contain well-formed * text of any length, including no text at all ("$empty=;"). * The right hand side may contain embedded UnicodeSet * patterns, for example, "$softvowel=[eiyEIY]".
*
ai>$alefmadda;
*
Forward translation rule. This rule * states that the string on the left will be changed to the * string on the right when performing forward * transliteration.
*
ai<$alefmadda;
*
Reverse translation rule. This rule * states that the string on the right will be changed to * the string on the left when performing reverse * transliteration.
*
* *
*
ai<>$alefmadda;
*
Bidirectional translation rule. This * rule states that the string on the right will be changed * to the string on the left when performing forward * transliteration, and vice versa when performing reverse * transliteration.
*
* *

Translation rules consist of a match pattern and an output * string. The match pattern consists of literal characters, * optionally preceded by context, and optionally followed by * context. Context characters, like literal pattern characters, * must be matched in the text being transliterated. However, unlike * literal pattern characters, they are not replaced by the output * text. For example, the pattern "abc{def}" * indicates the characters "def" must be * preceded by "abc" for a successful match. * If there is a successful match, "def" will * be replaced, but not "abc". The final '}' * is optional, so "abc{def" is equivalent to * "abc{def}". Another example is "{123}456" * (or "123}456") in which the literal * pattern "123" must be followed by "456". * *

The output string of a forward or reverse rule consists of * characters to replace the literal pattern characters. If the * output string contains the character '|', this is * taken to indicate the location of the cursor after * replacement. The cursor is the point in the text at which the * next replacement, if any, will be applied. The cursor is usually * placed within the replacement text; however, it can actually be * placed into the preceding or following context by using the * special character '@'. Examples: * *

 *     a {foo} z > | @ bar; # foo -> bar, move cursor before a
 *     {foo} xyz > bar @@|; # foo -> bar, cursor between y and z
 * 
* *

UnicodeSet * *

UnicodeSet patterns may appear anywhere that * makes sense. They may appear in variable definitions. * Contrariwise, UnicodeSet patterns may themselves * contain variable references, such as "$a=[a-z];$not_a=[^$a]", * or "$range=a-z;$ll=[$range]". * *

UnicodeSet patterns may also be embedded directly * into rule strings. Thus, the following two rules are equivalent: * *

 *     $vowel=[aeiou]; $vowel>'*'; # One way to do this
 *     [aeiou]>'*'; # Another way
 * 
* *

See {@link UnicodeSet} for more documentation and examples. * *

Segments * *

Segments of the input string can be matched and copied to the * output string. This makes certain sets of rules simpler and more * general, and makes reordering possible. For example: * *

 *     ([a-z]) > $1 $1; # double lowercase letters
 *     ([:Lu:]) ([:Ll:]) > $2 $1; # reverse order of Lu-Ll pairs
 * 
* *

The segment of the input string to be copied is delimited by * "(" and ")". Up to * nine segments may be defined. Segments may not overlap. In the * output string, "$1" through "$9" * represent the input string segments, in left-to-right order of * definition. * *

Anchors * *

Patterns can be anchored to the beginning or the end of the text. This is done with the * special characters '^' and '$'. For example: * *

 *   ^ a   > 'BEG_A';   # match 'a' at start of text
 *     a   > 'A'; # match other instances of 'a'
 *     z $ > 'END_Z';   # match 'z' at end of text
 *     z   > 'Z';       # match other instances of 'z'
 * 
* *

It is also possible to match the beginning or the end of the text using a UnicodeSet. * This is done by including a virtual anchor character '$' at the end of the * set pattern. Although this is usually the match character for the end anchor, the set will * match either the beginning or the end of the text, depending on its placement. For * example: * *

 *   $x = [a-z$];   # match 'a' through 'z' OR anchor
 *   $x 1    > 2;   # match '1' after a-z or at the start
 *      3 $x > 4;   # match '3' before a-z or at the end
 * 
* *

Example * *

The following example rules illustrate many of the features of * the rule language. * * * * * * * * * * * * * * *
Rule 1.abc{def}>x|y
Rule 2.xyz>r
Rule 3.yz>q
* *

Applying these rules to the string "adefabcdefz" * yields the following results: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|adefabcdefzInitial state, no rules match. Advance * cursor.
a|defabcdefzStill no match. Rule 1 does not match * because the preceding context is not present.
ad|efabcdefzStill no match. Keep advancing until * there is a match...
ade|fabcdefz...
adef|abcdefz...
adefa|bcdefz...
adefab|cdefz...
adefabc|defzRule 1 matches; replace "def" * with "xy" and back up the cursor * to before the 'y'.
adefabcx|yzAlthough "xyz" is * present, rule 2 does not match because the cursor is * before the 'y', not before the 'x'. * Rule 3 does match. Replace "yz" * with "q".
adefabcxq|The cursor is at the end; * transliteration is complete.
* *

The order of rules is significant. If multiple rules may match * at some point, the first matching rule is applied. * *

Forward and reverse rules may have an empty output string. * Otherwise, an empty left or right hand side of any statement is a * syntax error. * *

Single quotes are used to quote any character other than a * digit or letter. To specify a single quote itself, inside or * outside of quotes, use two single quotes in a row. For example, * the rule "'>'>o''clock" changes the * string ">" to the string "o'clock". * *

Notes * *

While a Transliterator is being built from rules, it checks that * the rules are added in proper order. For example, if the rule * "a>x" is followed by the rule "ab>y", * then the second rule will throw an exception. The reason is that * the second rule can never be triggered, since the first rule * always matches anything it matches. In other words, the first * rule masks the second rule. * * @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 * 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. * @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 * filter.contains() returns false will not be * altered by this transliterator. If filter is * null 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 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 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; 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 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 * 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. * *

* * @param insertion text to be inserted and possibly * transliterated into the translation buffer at * 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 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 * index.limit. * @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. * @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, 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 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 * 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. * * * *

Implementations of this method should also obey the * following invariants:

* * * *

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 * and wrapping transliterators 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 * @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. * @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 accommodate 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. * *

If this transliterator has a filter, break up the input text into runs * of unfiltered characters. Pass each run to * subclass.handleTransliterate(). * *

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 accommodate 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 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 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 createInstance(), 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 * java.text package. * *

If no localized names exist in the system resource bundles, * a name is synthesized using a localized * 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 ICU 2.0 */ static UnicodeString& U_EXPORT2 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 ICU 2.0 */ 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. * @stable ICU 2.4 */ UnicodeFilter* orphanFilter(void); /** * 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. * @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 getID() * returns "A-B", then this method will return the result of * createInstance("B-A"), or null if that * call fails. * *

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 null if no such * transliterator is registered. * @see #registerInstance * @stable ICU 2.0 */ 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 receive 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 * @stable ICU 2.0 */ static Transliterator* U_EXPORT2 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 * @stable ICU 2.0 */ static Transliterator* U_EXPORT2 createInstance(const UnicodeString& ID, UTransDirection dir, UErrorCode& status); /** * Returns a Transliterator object constructed from * the given rule string. This will be a rule-based Transliterator, * if the rule string contains only rules, or a * compound Transliterator, if it contains ID blocks, or a * null Transliterator, 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 receive information on position * of error if an error is encountered * @param status Output param set to success/failure code. * @return a newly created Transliterator * @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. * *

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]. * *

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. * * Because ICU may choose to cache Transliterators internally, this must * be called at application startup, prior to any calls to * Transliterator::createXXX to avoid undefined behavior. * * @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 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. * * Because ICU may choose to cache Transliterators internally, this must * be called at application startup, prior to any calls to * Transliterator::createXXX to avoid undefined behavior. * * @param adoptedObj an instance of subclass of * Transliterator that defines clone() * @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, createInstance(aliasID) * will return the same thing as createInstance(realID). * 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 /** * @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. * @internal */ 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: * *

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. * *

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); #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. * * Because ICU may choose to cache Transliterators internally, this should * be called during application shutdown, after all calls to * Transliterator::createXXX to avoid undefined behavior. * * @param ID the ID of the transliterator or class * @return the Object that was registered with * ID, or null 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 parameter 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 parameter 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 parameter 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 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. * *

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 override = 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((char16_t)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_HIDE_INTERNAL_API */ U_NAMESPACE_END #endif /* #if !UCONFIG_NO_TRANSLITERATION */ #endif /* U_SHOW_CPLUSPLUS_API */ #endif