492 lines
21 KiB
C++
492 lines
21 KiB
C++
/*
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*
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* (C) Copyright IBM Corp. 1998-2006 - All Rights Reserved
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*
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* This file is a modification of the ICU file IndicReordering.cpp
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* by Jens Herden and Javier Sola for Khmer language
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*
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*/
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#include "LETypes.h"
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#include "OpenTypeTables.h"
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#include "KhmerReordering.h"
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#include "LEGlyphStorage.h"
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U_NAMESPACE_BEGIN
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// Characters that get refered to by name...
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enum
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{
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C_SIGN_ZWNJ = 0x200C,
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C_SIGN_ZWJ = 0x200D,
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C_DOTTED_CIRCLE = 0x25CC,
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C_RO = 0x179A,
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C_VOWEL_AA = 0x17B6,
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C_SIGN_NIKAHIT = 0x17C6,
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C_VOWEL_E = 0x17C1,
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C_COENG = 0x17D2
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};
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enum
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{
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// simple classes, they are used in the statetable (in this file) to control the length of a syllable
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// they are also used to know where a character should be placed (location in reference to the base character)
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// and also to know if a character, when independtly displayed, should be displayed with a dotted-circle to
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// indicate error in syllable construction
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_xx = KhmerClassTable::CC_RESERVED,
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_sa = KhmerClassTable::CC_SIGN_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_POS_ABOVE,
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_sp = KhmerClassTable::CC_SIGN_AFTER | KhmerClassTable::CF_DOTTED_CIRCLE| KhmerClassTable::CF_POS_AFTER,
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_c1 = KhmerClassTable::CC_CONSONANT | KhmerClassTable::CF_CONSONANT,
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_c2 = KhmerClassTable::CC_CONSONANT2 | KhmerClassTable::CF_CONSONANT,
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_c3 = KhmerClassTable::CC_CONSONANT3 | KhmerClassTable::CF_CONSONANT,
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_rb = KhmerClassTable::CC_ROBAT | KhmerClassTable::CF_POS_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE,
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_cs = KhmerClassTable::CC_CONSONANT_SHIFTER | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_SHIFTER,
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_dl = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_BEFORE | KhmerClassTable::CF_DOTTED_CIRCLE,
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_db = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_BELOW | KhmerClassTable::CF_DOTTED_CIRCLE,
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_da = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_ABOVE_VOWEL,
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_dr = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_AFTER | KhmerClassTable::CF_DOTTED_CIRCLE,
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_co = KhmerClassTable::CC_COENG | KhmerClassTable::CF_COENG | KhmerClassTable::CF_DOTTED_CIRCLE,
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// split vowel
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_va = _da | KhmerClassTable::CF_SPLIT_VOWEL,
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_vr = _dr | KhmerClassTable::CF_SPLIT_VOWEL
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};
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// Character class tables
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// _xx character does not combine into syllable, such as numbers, puntuation marks, non-Khmer signs...
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// _sa Sign placed above the base
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// _sp Sign placed after the base
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// _c1 Consonant of type 1 or independent vowel (independent vowels behave as type 1 consonants)
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// _c2 Consonant of type 2 (only RO)
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// _c3 Consonant of type 3
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// _rb Khmer sign robat u17CC. combining mark for subscript consonants
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// _cd Consonant-shifter
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// _dl Dependent vowel placed before the base (left of the base)
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// _db Dependent vowel placed below the base
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// _da Dependent vowel placed above the base
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// _dr Dependent vowel placed behind the base (right of the base)
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// _co Khmer combining mark COENG u17D2, combines with the consonant or independent vowel following
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// it to create a subscript consonant or independent vowel
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// _va Khmer split vowel in wich the first part is before the base and the second one above the base
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// _vr Khmer split vowel in wich the first part is before the base and the second one behind (right of) the base
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static const KhmerClassTable::CharClass khmerCharClasses[] =
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{
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_c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c1, _c1, // 1780 - 178F
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_c1, _c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c2, _c1, _c1, _c1, _c3, _c3, // 1790 - 179F
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_c1, _c3, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, // 17A0 - 17AF
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_c1, _c1, _c1, _c1, _dr, _dr, _dr, _da, _da, _da, _da, _db, _db, _db, _va, _vr, // 17B0 - 17BF
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_vr, _dl, _dl, _dl, _vr, _vr, _sa, _sp, _sp, _cs, _cs, _sa, _rb, _sa, _sa, _sa, // 17C0 - 17CF
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_sa, _sa, _co, _sa, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _sa, _xx, _xx, // 17D0 - 17DF
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};
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//
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// Khmer Class Tables
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//
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//
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// The range of characters defined in the above table is defined here. FOr Khmer 1780 to 17DF
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// Even if the Khmer range is bigger, all other characters are not combinable, and therefore treated
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// as _xx
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static const KhmerClassTable khmerClassTable = {0x1780, 0x17df, khmerCharClasses};
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// Below we define how a character in the input string is either in the khmerCharClasses table
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// (in which case we get its type back), a ZWJ or ZWNJ (two characters that may appear
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// within the syllable, but are not in the table) we also get their type back, or an unknown object
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// in which case we get _xx (CC_RESERVED) back
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KhmerClassTable::CharClass KhmerClassTable::getCharClass(LEUnicode ch) const
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{
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if (ch == C_SIGN_ZWJ) {
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return CC_ZERO_WIDTH_J_MARK;
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}
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if (ch == C_SIGN_ZWNJ) {
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return CC_ZERO_WIDTH_NJ_MARK;
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}
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if (ch < firstChar || ch > lastChar) {
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return CC_RESERVED;
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}
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return classTable[ch - firstChar];
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}
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const KhmerClassTable *KhmerClassTable::getKhmerClassTable()
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{
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return &khmerClassTable;
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}
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class KhmerReorderingOutput : public UMemory {
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private:
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le_int32 fOutIndex;
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LEUnicode *fOutChars;
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LEGlyphStorage &fGlyphStorage;
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public:
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KhmerReorderingOutput(LEUnicode *outChars, LEGlyphStorage &glyphStorage)
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: fOutIndex(0), fOutChars(outChars), fGlyphStorage(glyphStorage)
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{
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// nothing else to do...
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}
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~KhmerReorderingOutput()
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{
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// nothing to do here...
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}
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void writeChar(LEUnicode ch, le_uint32 charIndex, FeatureMask charFeatures)
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{
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LEErrorCode success = LE_NO_ERROR;
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fOutChars[fOutIndex] = ch;
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fGlyphStorage.setCharIndex(fOutIndex, charIndex, success);
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fGlyphStorage.setAuxData(fOutIndex, charFeatures, success);
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fOutIndex += 1;
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}
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le_int32 getOutputIndex()
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{
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return fOutIndex;
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}
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};
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#define blwfFeatureTag LE_BLWF_FEATURE_TAG
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#define pstfFeatureTag LE_PSTF_FEATURE_TAG
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#define presFeatureTag LE_PRES_FEATURE_TAG
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#define blwsFeatureTag LE_BLWS_FEATURE_TAG
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#define abvsFeatureTag LE_ABVS_FEATURE_TAG
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#define pstsFeatureTag LE_PSTS_FEATURE_TAG
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#define blwmFeatureTag LE_BLWM_FEATURE_TAG
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#define abvmFeatureTag LE_ABVM_FEATURE_TAG
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#define distFeatureTag LE_DIST_FEATURE_TAG
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#define prefFeatureTag LE_PREF_FEATURE_TAG
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#define abvfFeatureTag LE_ABVF_FEATURE_TAG
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#define cligFeatureTag LE_CLIG_FEATURE_TAG
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#define mkmkFeatureTag LE_MKMK_FEATURE_TAG
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#define prefFeatureMask 0x80000000UL
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#define blwfFeatureMask 0x40000000UL
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#define abvfFeatureMask 0x20000000UL
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#define pstfFeatureMask 0x10000000UL
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#define presFeatureMask 0x08000000UL
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#define blwsFeatureMask 0x04000000UL
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#define abvsFeatureMask 0x02000000UL
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#define pstsFeatureMask 0x01000000UL
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#define cligFeatureMask 0x00800000UL
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#define distFeatureMask 0x00400000UL
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#define blwmFeatureMask 0x00200000UL
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#define abvmFeatureMask 0x00100000UL
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#define mkmkFeatureMask 0x00080000UL
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#define tagPref (prefFeatureMask | presFeatureMask | cligFeatureMask | distFeatureMask)
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#define tagAbvf (abvfFeatureMask | abvsFeatureMask | cligFeatureMask | distFeatureMask | abvmFeatureMask | mkmkFeatureMask)
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#define tagPstf (blwfFeatureMask | blwsFeatureMask | prefFeatureMask | presFeatureMask | pstfFeatureMask | pstsFeatureMask | cligFeatureMask | distFeatureMask | blwmFeatureMask)
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#define tagBlwf (blwfFeatureMask | blwsFeatureMask | cligFeatureMask | distFeatureMask | blwmFeatureMask | mkmkFeatureMask)
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#define tagDefault (prefFeatureMask | blwfFeatureMask | presFeatureMask | blwsFeatureMask | cligFeatureMask | distFeatureMask | abvmFeatureMask | blwmFeatureMask | mkmkFeatureMask)
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// These are in the order in which the features need to be applied
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// for correct processing
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static const FeatureMap featureMap[] =
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{
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// Shaping features
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{prefFeatureTag, prefFeatureMask},
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{blwfFeatureTag, blwfFeatureMask},
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{abvfFeatureTag, abvfFeatureMask},
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{pstfFeatureTag, pstfFeatureMask},
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{presFeatureTag, presFeatureMask},
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{blwsFeatureTag, blwsFeatureMask},
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{abvsFeatureTag, abvsFeatureMask},
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{pstsFeatureTag, pstsFeatureMask},
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{cligFeatureTag, cligFeatureMask},
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// Positioning features
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{distFeatureTag, distFeatureMask},
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{blwmFeatureTag, blwmFeatureMask},
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{abvmFeatureTag, abvmFeatureMask},
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{mkmkFeatureTag, mkmkFeatureMask},
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};
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static const le_int32 featureMapCount = LE_ARRAY_SIZE(featureMap);
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// The stateTable is used to calculate the end (the length) of a well
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// formed Khmer Syllable.
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//
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// Each horizontal line is ordered exactly the same way as the values in KhmerClassTable
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// CharClassValues in KhmerReordering.h This coincidence of values allows the
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// follow up of the table.
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//
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// Each line corresponds to a state, which does not necessarily need to be a type
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// of component... for example, state 2 is a base, with is always a first character
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// in the syllable, but the state could be produced a consonant of any type when
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// it is the first character that is analysed (in ground state).
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//
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// Differentiating 3 types of consonants is necessary in order to
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// forbid the use of certain combinations, such as having a second
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// coeng after a coeng RO,
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// The inexistent possibility of having a type 3 after another type 3 is permitted,
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// eliminating it would very much complicate the table, and it does not create typing
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// problems, as the case above.
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//
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// The table is quite complex, in order to limit the number of coeng consonants
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// to 2 (by means of the table).
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//
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// There a peculiarity, as far as Unicode is concerned:
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// - The consonant-shifter is considered in two possible different
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// locations, the one considered in Unicode 3.0 and the one considered in
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// Unicode 4.0. (there is a backwards compatibility problem in this standard).
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// xx independent character, such as a number, punctuation sign or non-khmer char
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//
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// c1 Khmer consonant of type 1 or an independent vowel
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// that is, a letter in which the subscript for is only under the
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// base, not taking any space to the right or to the left
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//
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// c2 Khmer consonant of type 2, the coeng form takes space under
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// and to the left of the base (only RO is of this type)
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//
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// c3 Khmer consonant of type 3. Its subscript form takes space under
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// and to the right of the base.
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//
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// cs Khmer consonant shifter
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//
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// rb Khmer robat
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//
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// co coeng character (u17D2)
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//
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// dv dependent vowel (including split vowels, they are treated in the same way).
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// even if dv is not defined above, the component that is really tested for is
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// KhmerClassTable::CC_DEPENDENT_VOWEL, which is common to all dependent vowels
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//
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// zwj Zero Width joiner
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//
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// zwnj Zero width non joiner
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//
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// sa above sign
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//
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// sp post sign
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//
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// there are lines with equal content but for an easier understanding
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// (and maybe change in the future) we did not join them
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//
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static const le_int8 khmerStateTable[][KhmerClassTable::CC_COUNT] =
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{
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// xx c1 c2 c3 zwnj cs rb co dv sa sp zwj
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{ 1, 2, 2, 2, 1, 1, 1, 6, 1, 1, 1, 2}, // 0 - ground state
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{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}, // 1 - exit state (or sign to the right of the syllable)
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{-1, -1, -1, -1, 3, 4, 5, 6, 16, 17, 1, -1}, // 2 - Base consonant
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{-1, -1, -1, -1, -1, 4, -1, -1, 16, -1, -1, -1}, // 3 - First ZWNJ before a register shifter
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// It can only be followed by a shifter or a vowel
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{-1, -1, -1, -1, 15, -1, -1, 6, 16, 17, 1, 14}, // 4 - First register shifter
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{-1, -1, -1, -1, -1, -1, -1, -1, 20, -1, 1, -1}, // 5 - Robat
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{-1, 7, 8, 9, -1, -1, -1, -1, -1, -1, -1, -1}, // 6 - First Coeng
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{-1, -1, -1, -1, 12, 13, -1, 10, 16, 17, 1, 14}, // 7 - First consonant of type 1 after coeng
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{-1, -1, -1, -1, 12, 13, -1, -1, 16, 17, 1, 14}, // 8 - First consonant of type 2 after coeng
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{-1, -1, -1, -1, 12, 13, -1, 10, 16, 17, 1, 14}, // 9 - First consonant or type 3 after ceong
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{-1, 11, 11, 11, -1, -1, -1, -1, -1, -1, -1, -1}, // 10 - Second Coeng (no register shifter before)
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{-1, -1, -1, -1, 15, -1, -1, -1, 16, 17, 1, 14}, // 11 - Second coeng consonant (or ind. vowel) no register shifter before
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{-1, -1, 1, -1, -1, 13, -1, -1, 16, -1, -1, -1}, // 12 - Second ZWNJ before a register shifter
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{-1, -1, -1, -1, 15, -1, -1, -1, 16, 17, 1, 14}, // 13 - Second register shifter
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{-1, -1, -1, -1, -1, -1, -1, -1, 16, -1, -1, -1}, // 14 - ZWJ before vowel
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{-1, -1, -1, -1, -1, -1, -1, -1, 16, -1, -1, -1}, // 15 - ZWNJ before vowel
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{-1, -1, -1, -1, -1, -1, -1, -1, -1, 17, 1, 18}, // 16 - dependent vowel
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{-1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 18}, // 17 - sign above
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{-1, -1, -1, -1, -1, -1, -1, 19, -1, -1, -1, -1}, // 18 - ZWJ after vowel
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{-1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1}, // 19 - Third coeng
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{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1}, // 20 - dependent vowel after a Robat
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};
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const FeatureMap *KhmerReordering::getFeatureMap(le_int32 &count)
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{
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count = featureMapCount;
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return featureMap;
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}
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// Given an input string of characters and a location in which to start looking
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// calculate, using the state table, which one is the last character of the syllable
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// that starts in the starting position.
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le_int32 KhmerReordering::findSyllable(const KhmerClassTable *classTable, const LEUnicode *chars, le_int32 prev, le_int32 charCount)
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{
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le_int32 cursor = prev;
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le_int8 state = 0;
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while (cursor < charCount) {
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KhmerClassTable::CharClass charClass = (classTable->getCharClass(chars[cursor]) & KhmerClassTable::CF_CLASS_MASK);
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state = khmerStateTable[state][charClass];
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if (state < 0) {
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break;
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}
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cursor += 1;
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}
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return cursor;
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}
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// This is the real reordering function as applied to the Khmer language
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le_int32 KhmerReordering::reorder(const LEUnicode *chars, le_int32 charCount, le_int32 /*scriptCode*/,
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LEUnicode *outChars, LEGlyphStorage &glyphStorage)
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{
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const KhmerClassTable *classTable = KhmerClassTable::getKhmerClassTable();
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KhmerReorderingOutput output(outChars, glyphStorage);
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KhmerClassTable::CharClass charClass;
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le_int32 i, prev = 0, coengRo;
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// This loop only exits when we reach the end of a run, which may contain
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// several syllables.
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while (prev < charCount) {
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le_int32 syllable = findSyllable(classTable, chars, prev, charCount);
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// write a pre vowel or the pre part of a split vowel first
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// and look out for coeng + ro. RO is the only vowel of type 2, and
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// therefore the only one that requires saving space before the base.
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coengRo = -1; // There is no Coeng Ro, if found this value will change
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for (i = prev; i < syllable; i += 1) {
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charClass = classTable->getCharClass(chars[i]);
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// if a split vowel, write the pre part. In Khmer the pre part
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// is the same for all split vowels, same glyph as pre vowel C_VOWEL_E
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if (charClass & KhmerClassTable::CF_SPLIT_VOWEL) {
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output.writeChar(C_VOWEL_E, i, tagPref);
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break; // there can be only one vowel
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}
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// if a vowel with pos before write it out
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if (charClass & KhmerClassTable::CF_POS_BEFORE) {
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output.writeChar(chars[i], i, tagPref);
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break; // there can be only one vowel
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}
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// look for coeng + ro and remember position
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// works because coeng + ro is always in front of a vowel (if there is a vowel)
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// and because CC_CONSONANT2 is enough to identify it, as it is the only consonant
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// with this flag
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if ( (charClass & KhmerClassTable::CF_COENG) && (i + 1 < syllable) &&
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( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK) == KhmerClassTable::CC_CONSONANT2) )
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{
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coengRo = i;
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}
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}
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// write coeng + ro if found
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if (coengRo > -1) {
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output.writeChar(C_COENG, coengRo, tagPref);
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output.writeChar(C_RO, coengRo + 1, tagPref);
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}
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|
// shall we add a dotted circle?
|
|
// If in the position in which the base should be (first char in the string) there is
|
|
// a character that has the Dotted circle flag (a character that cannot be a base)
|
|
// then write a dotted circle
|
|
if (classTable->getCharClass(chars[prev]) & KhmerClassTable::CF_DOTTED_CIRCLE) {
|
|
output.writeChar(C_DOTTED_CIRCLE, prev, tagDefault);
|
|
}
|
|
|
|
// copy what is left to the output, skipping before vowels and coeng Ro if they are present
|
|
for (i = prev; i < syllable; i += 1) {
|
|
charClass = classTable->getCharClass(chars[i]);
|
|
|
|
// skip a before vowel, it was already processed
|
|
if (charClass & KhmerClassTable::CF_POS_BEFORE) {
|
|
continue;
|
|
}
|
|
|
|
// skip coeng + ro, it was already processed
|
|
if (i == coengRo) {
|
|
i += 1;
|
|
continue;
|
|
}
|
|
|
|
switch (charClass & KhmerClassTable::CF_POS_MASK) {
|
|
case KhmerClassTable::CF_POS_ABOVE :
|
|
output.writeChar(chars[i], i, tagAbvf);
|
|
break;
|
|
|
|
case KhmerClassTable::CF_POS_AFTER :
|
|
output.writeChar(chars[i], i, tagPstf);
|
|
break;
|
|
|
|
case KhmerClassTable::CF_POS_BELOW :
|
|
output.writeChar(chars[i], i, tagBlwf);
|
|
break;
|
|
|
|
default:
|
|
// assign the correct flags to a coeng consonant
|
|
// Consonants of type 3 are taged as Post forms and those type 1 as below forms
|
|
if ( (charClass & KhmerClassTable::CF_COENG) && i + 1 < syllable ) {
|
|
if ( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK)
|
|
== KhmerClassTable::CC_CONSONANT3) {
|
|
output.writeChar(chars[i], i, tagPstf);
|
|
i += 1;
|
|
output.writeChar(chars[i], i, tagPstf);
|
|
}
|
|
else {
|
|
output.writeChar(chars[i], i, tagBlwf);
|
|
i += 1;
|
|
output.writeChar(chars[i], i, tagBlwf);
|
|
}
|
|
break;
|
|
}
|
|
// if a shifter is followed by an above vowel change the shifter to below form,
|
|
// an above vowel can have two possible positions i + 1 or i + 3
|
|
// (position i+1 corresponds to unicode 3, position i+3 to Unicode 4)
|
|
// and there is an extra rule for C_VOWEL_AA + C_SIGN_NIKAHIT also for two
|
|
// different positions, right after the shifter or after a vowel (Unicode 4)
|
|
if ( (charClass & KhmerClassTable::CF_SHIFTER) && (i + 1 < syllable) ) {
|
|
if ((classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_ABOVE_VOWEL)
|
|
|| (i + 2 < syllable
|
|
&& ( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK) == C_VOWEL_AA)
|
|
&& ( (classTable->getCharClass(chars[i + 2]) & KhmerClassTable::CF_CLASS_MASK) == C_SIGN_NIKAHIT))
|
|
|| (i + 3 < syllable && (classTable->getCharClass(chars[i + 3]) & KhmerClassTable::CF_ABOVE_VOWEL))
|
|
|| (i + 4 < syllable
|
|
&& ( (classTable->getCharClass(chars[i + 3]) & KhmerClassTable::CF_CLASS_MASK) == C_VOWEL_AA)
|
|
&& ( (classTable->getCharClass(chars[i + 4]) & KhmerClassTable::CF_CLASS_MASK) == C_SIGN_NIKAHIT) ) )
|
|
{
|
|
output.writeChar(chars[i], i, tagBlwf);
|
|
break;
|
|
}
|
|
|
|
}
|
|
// default - any other characters
|
|
output.writeChar(chars[i], i, tagDefault);
|
|
break;
|
|
} // switch
|
|
} // for
|
|
|
|
prev = syllable; // move the pointer to the start of next syllable
|
|
}
|
|
|
|
return output.getOutputIndex();
|
|
}
|
|
|
|
|
|
U_NAMESPACE_END
|