icuSources/i18n/esctrn.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 **********************************************************************
   5 *   Copyright (c) 2001-2007, International Business Machines
   6 *   Corporation and others.  All Rights Reserved.
   7 **********************************************************************
   8 *   Date        Name        Description
   9 *   11/20/2001  aliu        Creation.
  10 **********************************************************************
  11 */
  12 #ifndef ESCTRN_H
  13 #define ESCTRN_H
  14
  15 #include "unicode/utypes.h"
  16
  17 #if !UCONFIG_NO_TRANSLITERATION
  18
  19 #include "unicode/translit.h"
  20
  21 U_NAMESPACE_BEGIN
  22
  23 /**
  24  * A transliterator that converts Unicode characters to an escape
  25  * form.  Examples of escape forms are "U+4E01" and "&#x10FFFF;".
  26  * Escape forms have a prefix and suffix, either of which may be
  27  * empty, a radix, typically 16 or 10, a minimum digit count,
  28  * typically 1, 4, or 8, and a boolean that specifies whether
  29  * supplemental characters are handled as 32-bit code points or as two
  30  * 16-bit code units.  Most escape forms handle 32-bit code points,
  31  * but some, such as the Java form, intentionally break them into two
  32  * surrogate pairs, for backward compatibility.
  33  *
  34  * <p>Some escape forms actually have two different patterns, one for
  35  * BMP characters (0..FFFF) and one for supplements (>FFFF).  To
  36  * handle this, a second EscapeTransliterator may be defined that
  37  * specifies the pattern to be produced for supplementals.  An example
  38  * of a form that requires this is the C form, which uses "\\uFFFF"
  39  * for BMP characters and "\\U0010FFFF" for supplementals.
  40  *
  41  * <p>This class is package private.  It registers several standard
  42  * variants with the system which are then accessed via their IDs.
  43  *
  44  * @author Alan Liu
  45  */
  46 class EscapeTransliterator : public Transliterator {
  47
  48  private:
  49
  50     /**
  51      * The prefix of the escape form; may be empty, but usually isn't.
  52      */
  53     UnicodeString prefix;
  54
  55     /**
  56      * The prefix of the escape form; often empty.
  57      */
  58     UnicodeString suffix;
  59
  60     /**
  61      * The radix to display the number in.  Typically 16 or 10.  Must
  62      * be in the range 2 to 36.
  63      */
  64     int32_t radix;
  65
  66     /**
  67      * The minimum number of digits.  Typically 1, 4, or 8.  Values
  68      * less than 1 are equivalent to 1.
  69      */
  70     int32_t minDigits;
  71
  72     /**
  73      * If true, supplementals are handled as 32-bit code points.  If
  74      * false, they are handled as two 16-bit code units.
  75      */
  76     UBool grokSupplementals;
  77
  78     /**
  79      * The form to be used for supplementals.  If this is null then
  80      * the same form is used for BMP characters and supplementals.  If
  81      * this is not null and if grokSupplementals is true then the
  82      * prefix, suffix, radix, and minDigits of this object are used
  83      * for supplementals.  This pointer is owned.
  84      */
  85     EscapeTransliterator* supplementalHandler;
  86
  87  public:
  88
  89     /**
  90      * Registers standard variants with the system.  Called by
  91      * Transliterator during initialization.
  92      */
  93     static void registerIDs();
  94
  95     /**
  96      * Constructs an escape transliterator with the given ID and
  97      * parameters.  See the class member documentation for details.
  98      */
  99     EscapeTransliterator(const UnicodeString& ID,
 100                          const UnicodeString& prefix, const UnicodeString& suffix,
 101                          int32_t radix, int32_t minDigits,
 102                          UBool grokSupplementals,
 103                          EscapeTransliterator* adoptedSupplementalHandler);
 104
 105     /**
 106      * Copy constructor.
 107      */
 108     EscapeTransliterator(const EscapeTransliterator&);
 109
 110     /**
 111      * Destructor.
 112      */
 113     virtual ~EscapeTransliterator();
 114
 115     /**
 116      * Transliterator API.
 117      */
 118     virtual Transliterator* clone() const;
 119
 120     /**
 121      * ICU "poor man's RTTI", returns a UClassID for the actual class.
 122      */
 123     virtual UClassID getDynamicClassID() const;
 124
 125     /**
 126      * ICU "poor man's RTTI", returns a UClassID for this class.
 127      */
 128     U_I18N_API static UClassID U_EXPORT2 getStaticClassID();
 129
 130  protected:
 131
 132     /**
 133      * Implements {@link Transliterator#handleTransliterate}.
 134      */
 135     virtual void handleTransliterate(Replaceable& text, UTransPosition& offset,
 136                              UBool isIncremental) const;
 137
 138 };
 139
 140 U_NAMESPACE_END
 141
 142 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
 143
 144 #endif