icuSources/layout/LigatureSubstSubtables.cpp

   1 /*
   2  * (C) Copyright IBM Corp. 1998-2006 - All Rights Reserved
   3  *
   4  */
   5
   6 #include "LETypes.h"
   7 #include "LEGlyphFilter.h"
   8 #include "OpenTypeTables.h"
   9 #include "GlyphSubstitutionTables.h"
  10 #include "LigatureSubstSubtables.h"
  11 #include "GlyphIterator.h"
  12 #include "LESwaps.h"
  13
  14 U_NAMESPACE_BEGIN
  15
  16 le_uint32 LigatureSubstitutionSubtable::process(GlyphIterator *glyphIterator, const LEGlyphFilter *filter) const
  17 {
  18     LEGlyphID glyph = glyphIterator->getCurrGlyphID();
  19     le_int32 coverageIndex = getGlyphCoverage(glyph);
  20
  21     if (coverageIndex >= 0) {
  22         Offset ligSetTableOffset = SWAPW(ligSetTableOffsetArray[coverageIndex]);
  23         const LigatureSetTable *ligSetTable = (const LigatureSetTable *) ((char *) this + ligSetTableOffset);
  24         le_uint16 ligCount = SWAPW(ligSetTable->ligatureCount);
  25
  26         for (le_uint16 lig = 0; lig < ligCount; lig += 1) {
  27             Offset ligTableOffset = SWAPW(ligSetTable->ligatureTableOffsetArray[lig]);
  28             const LigatureTable *ligTable = (const LigatureTable *) ((char *)ligSetTable + ligTableOffset);
  29             le_uint16 compCount = SWAPW(ligTable->compCount) - 1;
  30             le_int32 startPosition = glyphIterator->getCurrStreamPosition();
  31             TTGlyphID ligGlyph = SWAPW(ligTable->ligGlyph);
  32             le_uint16 comp;
  33
  34             for (comp = 0; comp < compCount; comp += 1) {
  35                 if (! glyphIterator->next()) {
  36                     break;
  37                 }
  38
  39                 if (LE_GET_GLYPH(glyphIterator->getCurrGlyphID()) != SWAPW(ligTable->componentArray[comp])) {
  40                     break;
  41                 }
  42             }
  43
  44             if (comp == compCount && (filter == NULL || filter->accept(LE_SET_GLYPH(glyph, ligGlyph)))) {
  45                 GlyphIterator tempIterator(*glyphIterator);
  46                 TTGlyphID deletedGlyph = tempIterator.ignoresMarks()? 0xFFFE : 0xFFFF;
  47
  48                 while (comp > 0) {
  49                     tempIterator.setCurrGlyphID(deletedGlyph);
  50                     tempIterator.prev();
  51
  52                     comp -= 1;
  53                 }
  54
  55                 tempIterator.setCurrGlyphID(ligGlyph);
  56
  57                 return compCount + 1;
  58             }
  59
  60             glyphIterator->setCurrStreamPosition(startPosition);
  61         }
  62
  63     }
  64
  65     return 0;
  66 }
  67
  68 U_NAMESPACE_END