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1/*
2 *
3 * (C) Copyright IBM Corp. 1998-2013 - All Rights Reserved
4 *
5 * Developed at DIT - Government of Bhutan
6 *
7 * Contact person: Pema Geyleg - <pema_geyleg@druknet.bt>
8 *
9 * This file is a modification of the ICU file KhmerReordering.h
10 * by Jens Herden and Javier Sola who have given all their possible rights to IBM and the Governement of Bhutan
11 * A first module for Dzongkha was developed by Karunakar under Panlocalisation funding.
12 * Assistance for this module has been received from Namgay Thinley, Christopher Fynn and Javier Sola
13 *
14 */
15
16#ifndef __TIBETANREORDERING_H
17#define __TIBETANREORDERING_H
18
19/**
20 * \file
21 * \internal
22 */
23
24// #include "LETypes.h"
25// #include "OpenTypeTables.h"
26
27U_NAMESPACE_BEGIN
28
29class LEGlyphStorage;
30
31// Vocabulary
32// Base -> A consonant in its full (not subscript) form. It is the
33// center of the syllable, it can be souranded by subjoined consonants, vowels,
34// signs... but there is only one base in a stack, it has to be coded as
35// the first character of the syllable.Included here are also groups of base + subjoined
36// which are represented by one single code point in unicode (e.g. 0F43) Also other characters that might take
37// subjoined consonants or other combining characters.
38// Subjoined -> Subjoined consonants and groups of subjoined consonants which have a single code-point
39// to repersent the group (even if each subjoined consonant is represented independently
40// by anothe code-point
41// Tsa Phru --> Tsa Phru character, Bhutanese people will always place it right after the base, but sometimes, due to
42// "normalization"
43// is placed after all the subjoined consonants, and it is also permitted there.
44// A Chung Vowel lengthening mark --> . 0F71 It is placed after the base and any subjoined consonants but before any vowels
45// Precomposed Sanskrit vowels --> The are combinations of subjoined consonants + vowels that have been assigned
46// a given code-point (in spite of each single part of them having also a code-point
47// They are avoided, and users are encouraged to use the combination of code-points that
48// represents the same sound instead of using this combined characters. This is included here
49// for compatibility with possible texts that use them (they are not in the Dzongkha keyboard).
50// Halanta -> The Halanta or Virama character 0F84 indicates that a consonant should not use its inheernt vowel,
51// in spite of not having other vowels present. It is usually placed immediatly after a base consonant,
52// but in some special cases it can also be placed after a subjoined consonant, so this is also
53// permitted in this algorithm. (Halanta is always displayed in Tibetan not used as a connecting char)
54//
55// Subjoined vowels -> Dependent vowels (matras) placed below the base and below all subjoined consonants. There
56// might be as much as three subjoined vowels in a given stack (only one in general text, but up
57// to three for abreviations, they have to be permitted).
58// Superscript vowels -> There are three superscript vowels, and they can be repeated or combined (up to three
59// times. They can combine with subjoined vowels, and are always coded after these.
60// Anusvara --> Nasalisation sign. Traditioinally placed in absence of vowels, but also after vowels. In some
61// special cases it can be placed before a vowel, so this is also permitted
62// Candrabindu -> Forms of the Anusvara with different glyphs (and different in identity) which can be placed
63// without vowel or after the vowel, but never before. Cannot combine with Anusvara.
64// Stress marks -> Marks placed above or below a syllable, affecting the whole syllable. They are combining
65// marks, so they have to be attached to a specific stack. The are using to emphasise a syllable.
66//
67// Digits -> Digits are not considered as non-combining characters because there are a few characters which
68// combine with them, so they have to be considered independently.
69// Digit combining marks -> dependent marks that combine with digits.
70//
71// TODO
72// There are a number of characters in the CJK block that are used in Tibetan script, two of these are symbols
73// are used as bases for combining glyphs, and have not been encoded in Tibetan. As these characters are outside
74// of the tibetan block, they have not been treated in this program.
75
76
77struct TibetanClassTable // This list must include all types of components that can be used inside a syllable
78{
79 enum CharClassValues // order is important here! This order must be the same that is found in each horizontal
80 // line in the statetable for Tibetan (file TibetanReordering.cpp). It assigns one number
81 // to each type of character that has to be considered when analysing the order in which
82 // characters can be placed
83 {
84 CC_RESERVED = 0, //Non Combining Characters
85 CC_BASE = 1, // Base Consonants, Base Consonants with Subjoined attached in code point, Sanskrit base marks
86 CC_SUBJOINED = 2, // Subjoined Consonats, combination of more than Subjoined Consonants in the code point
87 CC_TSA_PHRU = 3, // Tsa-Phru character 0F39
88 CC_A_CHUNG = 4, // Vowel Lenthening a-chung mark 0F71
89 CC_COMP_SANSKRIT = 5, // Precomposed Sanskrit vowels including Subjoined characters and vowels
90 CC_HALANTA = 6, // Halanta Character 0F84
91 CC_BELOW_VOWEL = 7, // Subjoined vowels
92 CC_ABOVE_VOWEL = 8, // Superscript vowels
93 CC_ANUSVARA = 9, // Tibetan sign Rjes Su Nga Ro 0F7E
94 CC_CANDRABINDU = 10, // Tibetan sign Sna Ldan and Nyi Zla Naa Da 0F82, 0F83
95 CC_VISARGA = 11, // Tibetan sign Rnam Bcad (0F7F)
96 CC_ABOVE_S_MARK = 12, // Stress Marks placed above the text
97 CC_BELOW_S_MARK = 13, // Stress Marks placed below the text
98 CC_DIGIT = 14, // Dzongkha Digits
99 CC_PRE_DIGIT_MARK = 15, // Mark placed before the digit
100 CC_POST_BELOW_DIGIT_M = 16, // Mark placed below or after the digit
101 CC_COUNT = 17 // This is the number of character classes
102 };
103
104 enum CharClassFlags
105 {
106 CF_CLASS_MASK = 0x0000FFFF,
107
108 CF_DOTTED_CIRCLE = 0x04000000, // add a dotted circle if a character with this flag is the first in a syllable
109 CF_DIGIT = 0x01000000, // flag to speed up comparaisson
110 CF_PREDIGIT = 0x02000000, // flag to detect pre-digit marks for reordering
111
112 // position flags
113 CF_POS_BEFORE = 0x00080000,
114 CF_POS_BELOW = 0x00040000,
115 CF_POS_ABOVE = 0x00020000,
116 CF_POS_AFTER = 0x00010000,
117 CF_POS_MASK = 0x000f0000
118 };
119
120 typedef le_uint32 CharClass;
121
122 typedef le_int32 ScriptFlags;
123
124 LEUnicode firstChar; // for Tibetan this will become xOF00
125 LEUnicode lastChar; // and this x0FFF
126 const CharClass *classTable;
127
128 CharClass getCharClass(LEUnicode ch) const;
129
130 static const TibetanClassTable *getTibetanClassTable();
131};
132
133
134class TibetanReordering /* not : public UObject because all methods are static */ {
135public:
136 static le_int32 reorder(const LEUnicode *theChars, le_int32 charCount, le_int32 scriptCode,
137 LEUnicode *outChars, LEGlyphStorage &glyphStorage);
138
139 static const FeatureMap *getFeatureMap(le_int32 &count);
140
141private:
142 // do not instantiate
143 TibetanReordering();
144
145 static le_int32 findSyllable(const TibetanClassTable *classTable, const LEUnicode *chars, le_int32 prev, le_int32 charCount);
146
147};
148
149
150U_NAMESPACE_END
151#endif