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diff --git a/intl/icu/source/i18n/unicode/translit.h b/intl/icu/source/i18n/unicode/translit.h new file mode 100644 index 000000000..b06879100 --- /dev/null +++ b/intl/icu/source/i18n/unicode/translit.h @@ -0,0 +1,1344 @@ +// Copyright (C) 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" + +/** + * \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. + * + * 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 <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. + * + * 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 + * <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 + /** + * @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: + * + * <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. + * + * 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 <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_HIDE_INTERNAL_API */ + +U_NAMESPACE_END + +#endif /* #if !UCONFIG_NO_TRANSLITERATION */ + +#endif |