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      1 /*
      2 **********************************************************************
      3 *   Copyright (c) 2001-2007, International Business Machines
      4 *   Corporation and others.  All Rights Reserved.
      5 **********************************************************************
      6 *   Date        Name        Description
      7 *   11/20/2001  aliu        Creation.
      8 **********************************************************************
      9 */
     10 #ifndef ESCTRN_H
     11 #define ESCTRN_H
     12 
     13 #include "unicode/utypes.h"
     14 
     15 #if !UCONFIG_NO_TRANSLITERATION
     16 
     17 #include "unicode/translit.h"
     18 
     19 U_NAMESPACE_BEGIN
     20 
     21 /**
     22  * A transliterator that converts Unicode characters to an escape
     23  * form.  Examples of escape forms are "U+4E01" and "".
     24  * Escape forms have a prefix and suffix, either of which may be
     25  * empty, a radix, typically 16 or 10, a minimum digit count,
     26  * typically 1, 4, or 8, and a boolean that specifies whether
     27  * supplemental characters are handled as 32-bit code points or as two
     28  * 16-bit code units.  Most escape forms handle 32-bit code points,
     29  * but some, such as the Java form, intentionally break them into two
     30  * surrogate pairs, for backward compatibility.
     31  *
     32  * <p>Some escape forms actually have two different patterns, one for
     33  * BMP characters (0..FFFF) and one for supplements (>FFFF).  To
     34  * handle this, a second EscapeTransliterator may be defined that
     35  * specifies the pattern to be produced for supplementals.  An example
     36  * of a form that requires this is the C form, which uses "\\uFFFF"
     37  * for BMP characters and "\\U0010FFFF" for supplementals.
     38  *
     39  * <p>This class is package private.  It registers several standard
     40  * variants with the system which are then accessed via their IDs.
     41  *
     42  * @author Alan Liu
     43  */
     44 class EscapeTransliterator : public Transliterator {
     45 
     46  private:
     47 
     48     /**
     49      * The prefix of the escape form; may be empty, but usually isn't.
     50      */
     51     UnicodeString prefix;
     52 
     53     /**
     54      * The prefix of the escape form; often empty.
     55      */
     56     UnicodeString suffix;
     57 
     58     /**
     59      * The radix to display the number in.  Typically 16 or 10.  Must
     60      * be in the range 2 to 36.
     61      */
     62     int32_t radix;
     63 
     64     /**
     65      * The minimum number of digits.  Typically 1, 4, or 8.  Values
     66      * less than 1 are equivalent to 1.
     67      */
     68     int32_t minDigits;
     69 
     70     /**
     71      * If true, supplementals are handled as 32-bit code points.  If
     72      * false, they are handled as two 16-bit code units.
     73      */
     74     UBool grokSupplementals;
     75 
     76     /**
     77      * The form to be used for supplementals.  If this is null then
     78      * the same form is used for BMP characters and supplementals.  If
     79      * this is not null and if grokSupplementals is true then the
     80      * prefix, suffix, radix, and minDigits of this object are used
     81      * for supplementals.  This pointer is owned.
     82      */
     83     EscapeTransliterator* supplementalHandler;
     84 
     85  public:
     86 
     87     /**
     88      * Registers standard variants with the system.  Called by
     89      * Transliterator during initialization.
     90      */
     91     static void registerIDs();
     92 
     93     /**
     94      * Constructs an escape transliterator with the given ID and
     95      * parameters.  See the class member documentation for details.
     96      */
     97     EscapeTransliterator(const UnicodeString& ID,
     98                          const UnicodeString& prefix, const UnicodeString& suffix,
     99                          int32_t radix, int32_t minDigits,
    100                          UBool grokSupplementals,
    101                          EscapeTransliterator* adoptedSupplementalHandler);
    102 
    103     /**
    104      * Copy constructor.
    105      */
    106     EscapeTransliterator(const EscapeTransliterator&);
    107 
    108     /**
    109      * Destructor.
    110      */
    111     virtual ~EscapeTransliterator();
    112 
    113     /**
    114      * Transliterator API.
    115      */
    116     virtual Transliterator* clone() const;
    117 
    118     /**
    119      * ICU "poor man's RTTI", returns a UClassID for the actual class.
    120      */
    121     virtual UClassID getDynamicClassID() const;
    122 
    123     /**
    124      * ICU "poor man's RTTI", returns a UClassID for this class.
    125      */
    126     U_I18N_API static UClassID U_EXPORT2 getStaticClassID();
    127 
    128  protected:
    129 
    130     /**
    131      * Implements {@link Transliterator#handleTransliterate}.
    132      */
    133     virtual void handleTransliterate(Replaceable& text, UTransPosition& offset,
    134                              UBool isIncremental) const;
    135 
    136 };
    137 
    138 U_NAMESPACE_END
    139 
    140 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
    141 
    142 #endif
    143