icuSources/layout/LigatureSubstSubtables.cpp

   1 /*
   2  * %W% %E%
   3  *
   4  * (C) Copyright IBM Corp. 1998-2003 - All Rights Reserved
   5  *
   6  */
   7
   8 #include "LETypes.h"
   9 #include "LEGlyphFilter.h"
  10 #include "OpenTypeTables.h"
  11 #include "GlyphSubstitutionTables.h"
  12 #include "LigatureSubstSubtables.h"
  13 #include "GlyphIterator.h"
  14 #include "LESwaps.h"
  15
  16 U_NAMESPACE_BEGIN
  17
  18 le_uint32 LigatureSubstitutionSubtable::process(GlyphIterator *glyphIterator, const LEGlyphFilter *filter) const
  19 {
  20     LEGlyphID glyph = glyphIterator->getCurrGlyphID();
  21     le_int32 coverageIndex = getGlyphCoverage(glyph);
  22
  23     if (coverageIndex >= 0) {
  24         Offset ligSetTableOffset = SWAPW(ligSetTableOffsetArray[coverageIndex]);
  25         const LigatureSetTable *ligSetTable = (const LigatureSetTable *) ((char *) this + ligSetTableOffset);
  26         le_uint16 ligCount = SWAPW(ligSetTable->ligatureCount);
  27
  28         for (le_uint16 lig = 0; lig < ligCount; lig += 1) {
  29             Offset ligTableOffset = SWAPW(ligSetTable->ligatureTableOffsetArray[lig]);
  30             const LigatureTable *ligTable = (const LigatureTable *) ((char *)ligSetTable + ligTableOffset);
  31             le_uint16 compCount = SWAPW(ligTable->compCount) - 1;
  32             le_int32 startPosition = glyphIterator->getCurrStreamPosition();
  33             TTGlyphID ligGlyph = SWAPW(ligTable->ligGlyph);
  34             le_uint16 comp;
  35
  36             if (filter != NULL && ! filter->accept(LE_SET_GLYPH(glyph, ligGlyph))) {
  37                 continue;
  38             }
  39
  40             for (comp = 0; comp < compCount; comp += 1) {
  41                 if (! glyphIterator->next()) {
  42                     break;
  43                 }
  44
  45                 if (LE_GET_GLYPH(glyphIterator->getCurrGlyphID()) != SWAPW(ligTable->componentArray[comp])) {
  46                     break;
  47                 }
  48             }
  49
  50             if (comp == compCount) {
  51                 GlyphIterator tempIterator(*glyphIterator);
  52                 TTGlyphID deletedGlyph = tempIterator.ignoresMarks()? 0xFFFE : 0xFFFF;
  53
  54                 while (comp > 0) {
  55                     tempIterator.setCurrGlyphID(deletedGlyph);
  56                     tempIterator.prev();
  57
  58                     comp -= 1;
  59                 }
  60
  61                 tempIterator.setCurrGlyphID(ligGlyph);
  62
  63                 return compCount + 1;
  64             }
  65
  66             glyphIterator->setCurrStreamPosition(startPosition);
  67         }
  68
  69     }
  70
  71     return 0;
  72 }
  73
  74 U_NAMESPACE_END