icuSources/i18n/esctrn.h

   1 /*
   2 **********************************************************************
   3 *   Copyright (c) 2001-2006, 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 "&#x10FFFF;".
  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 U_I18N_API 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     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