1/*
2 * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
3 *
4 * This file is a modification of the ICU file IndicReordering.h
5 * by Jens Herden and Javier Sola for Khmer language
6 *
7 */
8
9#ifndef __KHMERREORDERING_H
10#define __KHMERREORDERING_H
11
12/**
13 * \file
14 * \internal
15 */
16
17#include "LETypes.h"
18#include "OpenTypeTables.h"
19
20U_NAMESPACE_BEGIN
21
22class LEGlyphStorage;
23
24// Vocabulary
25//     Base ->         A consonant or an independent vowel in its full (not subscript) form. It is the
26//                     center of the syllable, it can be souranded by coeng (subscript) consonants, vowels,
27//                     split vowels, signs... but there is only one base in a syllable, it has to be coded as
28//                     the first character of the syllable.
29//     split vowel --> vowel that has two parts placed separately (e.g. Before and after the consonant).
30//                     Khmer language has five of them. Khmer split vowels either have one part before the
31//                     base and one after the base or they have a part before the base and a part above the base.
32//                     The first part of all Khmer split vowels is the same character, identical to
33//                     the glyph of Khmer dependent vowel SRA EI
34//     coeng -->  modifier used in Khmer to construct coeng (subscript) consonants
35//                Differently than indian languages, the coeng modifies the consonant that follows it,
36//                not the one preceding it  Each consonant has two forms, the base form and the subscript form
37//                the base form is the normal one (using the consonants code-point), the subscript form is
38//                displayed when the combination coeng + consonant is encountered.
39//     Consonant of type 1 -> A consonant which has subscript for that only occupies space under a base consonant
40//     Consonant of type 2.-> Its subscript form occupies space under and before the base (only one, RO)
41//     Consonant of Type 3 -> Its subscript form occupies space under and after the base (KHO, CHHO, THHO, BA, YO, SA)
42//     Consonant shifter -> Khmer has to series of consonants. The same dependent vowel has different sounds
43//                          if it is attached to a consonant of the first series or a consonant of the second series
44//                          Most consonants have an equivalent in the other series, but some of theme exist only in
45//                          one series (for example SA). If we want to use the consonant SA with a vowel sound that
46//                          can only be done with a vowel sound that corresponds to a vowel accompanying a consonant
47//                          of the other series, then we need to use a consonant shifter: TRIISAP or MUSIKATOAN
48//                          x17C9 y x17CA. TRIISAP changes a first series consonant to second series sound and
49//                          MUSIKATOAN a second series consonant to have a first series vowel sound.
50//                          Consonant shifter are both normally supercript marks, but, when they are followed by a
51//                          superscript, they change shape and take the form of subscript dependent vowel SRA U.
52//                          If they are in the same syllable as a coeng consonant, Unicode 3.0 says that they
53//                          should be typed before the coeng. Unicode 4.0 breaks the standard and says that it should
54//                          be placed after the coeng consonant.
55//     Dependent vowel ->   In khmer dependent vowels can be placed above, below, before or after the base
56//                          Each vowel has its own position. Only one vowel per syllable is allowed.
57//     Signs            ->  Khmer has above signs and post signs. Only one above sign and/or one post sign are
58//                          Allowed in a syllable.
59//
60//
61
62struct KhmerClassTable    // This list must include all types of components that can be used inside a syllable
63{
64    enum CharClassValues  // order is important here! This order must be the same that is found in each horizontal
65                          // line in the statetable for Khmer (file KhmerReordering.cpp).
66    {
67        CC_RESERVED             =  0,
68        CC_CONSONANT            =  1, // consonant of type 1 or independent vowel
69        CC_CONSONANT2           =  2, // Consonant of type 2
70        CC_CONSONANT3           =  3, // Consonant of type 3
71        CC_ZERO_WIDTH_NJ_MARK   =  4, // Zero Width non joiner character (0x200C)
72        CC_CONSONANT_SHIFTER    =  5,
73        CC_ROBAT                =  6, // Khmer special diacritic accent -treated differently in state table
74        CC_COENG                =  7, // Subscript consonant combining character
75        CC_DEPENDENT_VOWEL      =  8,
76        CC_SIGN_ABOVE           =  9,
77        CC_SIGN_AFTER           = 10,
78        CC_ZERO_WIDTH_J_MARK    = 11, // Zero width joiner character
79        CC_COUNT                = 12  // This is the number of character classes
80    };
81
82    enum CharClassFlags
83    {
84        CF_CLASS_MASK    = 0x0000FFFF,
85
86        CF_CONSONANT     = 0x01000000,  // flag to speed up comparing
87        CF_SPLIT_VOWEL   = 0x02000000,  // flag for a split vowel -> the first part is added in front of the syllable
88        CF_DOTTED_CIRCLE = 0x04000000,  // add a dotted circle if a character with this flag is the first in a syllable
89        CF_COENG         = 0x08000000,  // flag to speed up comparing
90        CF_SHIFTER       = 0x10000000,  // flag to speed up comparing
91        CF_ABOVE_VOWEL   = 0x20000000,  // flag to speed up comparing
92
93        // position flags
94        CF_POS_BEFORE    = 0x00080000,
95        CF_POS_BELOW     = 0x00040000,
96        CF_POS_ABOVE     = 0x00020000,
97        CF_POS_AFTER     = 0x00010000,
98        CF_POS_MASK      = 0x000f0000
99    };
100
101    typedef le_uint32 CharClass;
102
103    typedef le_int32 ScriptFlags;
104
105    LEUnicode firstChar;   // for Khmer this will become x1780
106    LEUnicode lastChar;    //  and this x17DF
107    const CharClass *classTable;
108
109    CharClass getCharClass(LEUnicode ch) const;
110
111    static const KhmerClassTable *getKhmerClassTable();
112};
113
114
115class KhmerReordering /* not : public UObject because all methods are static */ {
116public:
117    static le_int32 reorder(const LEUnicode *theChars, le_int32 charCount, le_int32 scriptCode,
118        LEUnicode *outChars, LEGlyphStorage &glyphStorage);
119
120    static const FeatureMap *getFeatureMap(le_int32 &count);
121
122private:
123    // do not instantiate
124    KhmerReordering();
125
126    static le_int32 findSyllable(const KhmerClassTable *classTable, const LEUnicode *chars, le_int32 prev, le_int32 charCount);
127
128};
129
130
131U_NAMESPACE_END
132#endif
133