icuSources/layout/MultipleSubstSubtables.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2008 - 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, LEErrorCode& success, const LEGlyphFilter *filter) const
  18 {
  19     if (LE_FAILURE(success)) {
  20         return 0;
  21     }
  22
  23     LEGlyphID glyph = glyphIterator->getCurrGlyphID();
  24
  25     // If there's a filter, we only want to do the
  26     // substitution if the *input* glyphs doesn't
  27     // exist.
  28     //
  29     // FIXME: is this always the right thing to do?
  30     // FIXME: should this only be done for a non-zero
  31     //        glyphCount?
  32     if (filter != NULL && filter->accept(glyph)) {
  33         return 0;
  34     }
  35
  36     le_int32 coverageIndex = getGlyphCoverage(glyph);
  37     le_uint16 seqCount = SWAPW(sequenceCount);
  38
  39     if (coverageIndex >= 0 && coverageIndex < seqCount) {
  40         Offset sequenceTableOffset = SWAPW(sequenceTableOffsetArray[coverageIndex]);
  41         const SequenceTable *sequenceTable = (const SequenceTable *) ((char *) this + sequenceTableOffset);
  42         le_uint16 glyphCount = SWAPW(sequenceTable->glyphCount);
  43
  44         if (glyphCount == 0) {
  45             glyphIterator->setCurrGlyphID(0xFFFF);
  46             return 1;
  47         } else if (glyphCount == 1) {
  48             TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[0]);
  49
  50             if (filter != NULL && ! filter->accept(LE_SET_GLYPH(glyph, substitute))) {
  51                 return 0;
  52             }
  53
  54             glyphIterator->setCurrGlyphID(substitute);
  55             return 1;
  56         } else {
  57             // If there's a filter, make sure all of the output glyphs
  58             // exist.
  59             if (filter != NULL) {
  60                 for (le_int32 i = 0; i < glyphCount; i += 1) {
  61                     TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[i]);
  62
  63                     if (! filter->accept(substitute)) {
  64                         return 0;
  65                     }
  66                 }
  67             }
  68
  69             LEGlyphID *newGlyphs = glyphIterator->insertGlyphs(glyphCount, success);
  70             if (LE_FAILURE(success)) {
  71                 return 0;
  72             }
  73
  74             le_int32 insert = 0, direction = 1;
  75
  76             if (glyphIterator->isRightToLeft()) {
  77                 insert = glyphCount - 1;
  78                 direction = -1;
  79             }
  80
  81             for (le_int32 i = 0; i < glyphCount; i += 1) {
  82                 TTGlyphID substitute = SWAPW(sequenceTable->substituteArray[i]);
  83
  84                 newGlyphs[insert] = LE_SET_GLYPH(glyph, substitute);
  85                 insert += direction;
  86             }
  87
  88             return 1;
  89         }
  90     }
  91
  92     return 0;
  93 }
  94
  95 U_NAMESPACE_END