icuSources/layout/MultipleSubstSubtables.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "LEGlyphFilter.h"
   9 #include "OpenTypeTables.h"
  10 #include "GlyphSubstitutionTables.h"
  11 #include "MultipleSubstSubtables.h"
  12 #include "GlyphIterator.h"
  13 #include "LESwaps.h"
  14
  15 U_NAMESPACE_BEGIN
  16
  17 le_uint32 MultipleSubstitutionSubtable::process(GlyphIterator *glyphIterator, const LEGlyphFilter *filter) const
  18 {
  19     LEGlyphID glyph = glyphIterator->getCurrGlyphID();
  20
  21     // If there's a filter, we only want to do the
  22     // substitution if the *input* glyphs doesn't
  23     // exist.
  24     //
  25     // FIXME: is this always the right thing to do?
  26     // FIXME: should this only be done for a non-zero
  27     //        glyphCount?
  28     if (filter != NULL && filter->accept(glyph)) {
  29         return 0;
  30     }
  31
  32     le_int32 coverageIndex = getGlyphCoverage(glyph);
  33     le_uint16 seqCount = SWAPW(sequenceCount);
  34
  35     if (coverageIndex >= 0 && coverageIndex < seqCount) {
  36         Offset sequenceTableOffset = SWAPW(sequenceTableOffsetArray[coverageIndex]);
  37         const SequenceTable *sequenceTable = (const SequenceTable *) ((char *) this + sequenceTableOffset);
  38         le_uint16 glyphCount = SWAPW(sequenceTable->glyphCount);
  39
  40         if (glyphCount == 0) {
  41             glyphIterator->setCurrGlyphID(0xFFFF);
  42             return 1;
  43         } else if (glyphCount == 1) {
  44             TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[0]);
  45
  46             if (filter != NULL && ! filter->accept(LE_SET_GLYPH(glyph, substitute))) {
  47                 return 0;
  48             }
  49
  50             glyphIterator->setCurrGlyphID(substitute);
  51             return 1;
  52         } else {
  53             // If there's a filter, make sure all of the output glyphs
  54             // exist.
  55             if (filter != NULL) {
  56                 for (le_int32 i = 0; i < glyphCount; i += 1) {
  57                     TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[i]);
  58
  59                     if (! filter->accept(substitute)) {
  60                         return 0;
  61                     }
  62                 }
  63             }
  64
  65             LEGlyphID *newGlyphs = glyphIterator->insertGlyphs(glyphCount);
  66             le_int32 insert = 0, direction = 1;
  67
  68             if (glyphIterator->isRightToLeft()) {
  69                 insert = glyphCount - 1;
  70                 direction = -1;
  71             }
  72
  73             for (le_int32 i = 0; i < glyphCount; i += 1) {
  74                 TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[i]);
  75
  76                 newGlyphs[insert] = LE_SET_GLYPH(glyph, substitute);
  77                 insert += direction;
  78             }
  79
  80             return 1;
  81         }
  82     }
  83
  84     return 0;
  85 }
  86
  87 U_NAMESPACE_END