152 lines
8.1 KiB
C++
152 lines
8.1 KiB
C++
/*
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*
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* (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
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*
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* Developed at DIT - Government of Bhutan
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*
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* Contact person: Pema Geyleg - <pema_geyleg@druknet.bt>
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*
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* This file is a modification of the ICU file KhmerReordering.h
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* by Jens Herden and Javier Sola who have given all their possible rights to IBM and the Governement of Bhutan
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* A first module for Dzongkha was developed by Karunakar under Panlocalisation funding.
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* Assistance for this module has been received from Namgay Thinley, Christopher Fynn and Javier Sola
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*
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*/
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#ifndef __TIBETANREORDERING_H
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#define __TIBETANORDERING_H
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/**
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* \file
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* \internal
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*/
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// #include "LETypes.h"
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// #include "OpenTypeTables.h"
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U_NAMESPACE_BEGIN
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class LEGlyphStorage;
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// Vocabulary
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// Base -> A consonant in its full (not subscript) form. It is the
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// center of the syllable, it can be souranded by subjoined consonants, vowels,
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// signs... but there is only one base in a stack, it has to be coded as
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// the first character of the syllable.Included here are also groups of base + subjoined
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// which are represented by one single code point in unicode (e.g. 0F43) Also other characters that might take
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// subjoined consonants or other combining characters.
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// Subjoined -> Subjoined consonants and groups of subjoined consonants which have a single code-point
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// to repersent the group (even if each subjoined consonant is represented independently
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// by anothe code-point
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// Tsa Phru --> Tsa Phru character, Bhutanese people will always place it right after the base, but sometimes, due to
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// "normalization"
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// is placed after all the subjoined consonants, and it is also permitted there.
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// A Chung Vowel lengthening mark --> . 0F71 It is placed after the base and any subjoined consonants but before any vowels
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// Precomposed Sanskrit vowels --> The are combinations of subjoined consonants + vowels that have been assigned
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// a given code-point (in spite of each single part of them having also a code-point
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// They are avoided, and users are encouraged to use the combination of code-points that
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// represents the same sound instead of using this combined characters. This is included here
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// for compatibility with possible texts that use them (they are not in the Dzongkha keyboard).
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// Halanta -> The Halanta or Virama character 0F84 indicates that a consonant should not use its inheernt vowel,
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// in spite of not having other vowels present. It is usually placed immediatly after a base consonant,
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// but in some special cases it can also be placed after a subjoined consonant, so this is also
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// permitted in this algorithm. (Halanta is always displayed in Tibetan not used as a connecting char)
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//
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// Subjoined vowels -> Dependent vowels (matras) placed below the base and below all subjoined consonants. There
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// might be as much as three subjoined vowels in a given stack (only one in general text, but up
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// to three for abreviations, they have to be permitted).
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// Superscript vowels -> There are three superscript vowels, and they can be repeated or combined (up to three
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// times. They can combine with subjoined vowels, and are always coded after these.
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// Anusvara --> Nasalisation sign. Traditioinally placed in absence of vowels, but also after vowels. In some
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// special cases it can be placed before a vowel, so this is also permitted
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// Candrabindu -> Forms of the Anusvara with different glyphs (and different in identity) which can be placed
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// without vowel or after the vowel, but never before. Cannot combine with Anusvara.
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// Stress marks -> Marks placed above or below a syllable, affecting the whole syllable. They are combining
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// marks, so they have to be attached to a specific stack. The are using to emphasise a syllable.
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//
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// Digits -> Digits are not considered as non-combining characters because there are a few characters which
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// combine with them, so they have to be considered independently.
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// Digit combining marks -> dependent marks that combine with digits.
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//
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// TODO
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// There are a number of characters in the CJK block that are used in Tibetan script, two of these are symbols
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// are used as bases for combining glyphs, and have not been encoded in Tibetan. As these characters are outside
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// of the tibetan block, they have not been treated in this program.
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struct TibetanClassTable // This list must include all types of components that can be used inside a syllable
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{
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enum CharClassValues // order is important here! This order must be the same that is found in each horizontal
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// line in the statetable for Tibetan (file TibetanReordering.cpp). It assigns one number
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// to each type of character that has to be considered when analysing the order in which
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// characters can be placed
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{
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CC_RESERVED = 0, //Non Combining Characters
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CC_BASE = 1, // Base Consonants, Base Consonants with Subjoined attached in code point, Sanskrit base marks
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CC_SUBJOINED = 2, // Subjoined Consonats, combination of more than Subjoined Consonants in the code point
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CC_TSA_PHRU = 3, // Tsa-Phru character 0F39
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CC_A_CHUNG = 4, // Vowel Lenthening a-chung mark 0F71
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CC_COMP_SANSKRIT = 5, // Precomposed Sanskrit vowels including Subjoined characters and vowels
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CC_HALANTA = 6, // Halanta Character 0F84
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CC_BELOW_VOWEL = 7, // Subjoined vowels
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CC_ABOVE_VOWEL = 8, // Superscript vowels
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CC_ANUSVARA = 9, // Tibetan sign Rjes Su Nga Ro 0F7E
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CC_CANDRABINDU = 10, // Tibetan sign Sna Ldan and Nyi Zla Naa Da 0F82, 0F83
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CC_VISARGA = 11, // Tibetan sign Rnam Bcad (0F7F)
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CC_ABOVE_S_MARK = 12, // Stress Marks placed above the text
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CC_BELOW_S_MARK = 13, // Stress Marks placed below the text
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CC_DIGIT = 14, // Dzongkha Digits
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CC_PRE_DIGIT_MARK = 15, // Mark placed before the digit
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CC_POST_BELOW_DIGIT_M = 16, // Mark placed below or after the digit
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CC_COUNT = 17 // This is the number of character classes
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};
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enum CharClassFlags
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{
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CF_CLASS_MASK = 0x0000FFFF,
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CF_DOTTED_CIRCLE = 0x04000000, // add a dotted circle if a character with this flag is the first in a syllable
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CF_DIGIT = 0x01000000, // flag to speed up comparaisson
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CF_PREDIGIT = 0x02000000, // flag to detect pre-digit marks for reordering
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// position flags
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CF_POS_BEFORE = 0x00080000,
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CF_POS_BELOW = 0x00040000,
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CF_POS_ABOVE = 0x00020000,
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CF_POS_AFTER = 0x00010000,
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CF_POS_MASK = 0x000f0000
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};
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typedef le_uint32 CharClass;
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typedef le_int32 ScriptFlags;
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LEUnicode firstChar; // for Tibetan this will become xOF00
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LEUnicode lastChar; // and this x0FFF
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const CharClass *classTable;
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CharClass getCharClass(LEUnicode ch) const;
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static const TibetanClassTable *getTibetanClassTable();
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};
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class TibetanReordering /* not : public UObject because all methods are static */ {
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public:
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static le_int32 reorder(const LEUnicode *theChars, le_int32 charCount, le_int32 scriptCode,
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LEUnicode *outChars, LEGlyphStorage &glyphStorage);
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static const FeatureMap *getFeatureMap(le_int32 &count);
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private:
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// do not instantiate
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TibetanReordering();
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static le_int32 findSyllable(const TibetanClassTable *classTable, const LEUnicode *chars, le_int32 prev, le_int32 charCount);
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};
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U_NAMESPACE_END
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#endif
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