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