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
19U_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 */
44class 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
138U_NAMESPACE_END
139
140#endif /* #if !UCONFIG_NO_TRANSLITERATION */
141
142#endif
143