icuSources/layout/LigatureSubstProc2.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp and Others. 1998-2013 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "MorphTables.h"
   9 #include "StateTables.h"
  10 #include "MorphStateTables.h"
  11 #include "SubtableProcessor2.h"
  12 #include "StateTableProcessor2.h"
  13 #include "LigatureSubstProc2.h"
  14 #include "LEGlyphStorage.h"
  15 #include "LESwaps.h"
  16
  17 U_NAMESPACE_BEGIN
  18
  19 #define ExtendedComplement(m) ((le_int32) (~((le_uint32) (m))))
  20 #define SignBit(m) ((ExtendedComplement(m) >> 1) & (le_int32)(m))
  21 #define SignExtend(v,m) (((v) & SignBit(m))? ((v) | ExtendedComplement(m)): (v))
  22
  23 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(LigatureSubstitutionProcessor2)
  24
  25 LigatureSubstitutionProcessor2::LigatureSubstitutionProcessor2(const MorphSubtableHeader2 *morphSubtableHeader)
  26   : StateTableProcessor2(morphSubtableHeader)
  27 {
  28     ligatureSubstitutionHeader = (const LigatureSubstitutionHeader2 *) morphSubtableHeader;
  29     ligActionOffset = SWAPL(ligatureSubstitutionHeader->ligActionOffset);
  30     componentOffset = SWAPL(ligatureSubstitutionHeader->componentOffset);
  31     ligatureOffset = SWAPL(ligatureSubstitutionHeader->ligatureOffset);
  32
  33     entryTable = (const LigatureSubstitutionStateEntry2 *) ((char *) &stateTableHeader->stHeader + entryTableOffset);
  34 }
  35
  36 LigatureSubstitutionProcessor2::~LigatureSubstitutionProcessor2()
  37 {
  38 }
  39
  40 void LigatureSubstitutionProcessor2::beginStateTable()
  41 {
  42     m = -1;
  43 }
  44
  45 le_uint16 LigatureSubstitutionProcessor2::processStateEntry(LEGlyphStorage &glyphStorage, le_int32 &currGlyph, EntryTableIndex2 index)
  46 {
  47     const LigatureSubstitutionStateEntry2 *entry = &entryTable[index];
  48     le_uint16 nextStateIndex = SWAPW(entry->nextStateIndex);
  49     le_uint16 flags = SWAPW(entry->entryFlags);
  50     le_uint16 ligActionIndex = SWAPW(entry->ligActionIndex);
  51
  52     if (flags & lsfSetComponent) {
  53         if (++m >= nComponents) {
  54             m = 0;
  55         }
  56         componentStack[m] = currGlyph;
  57     }
  58
  59     ByteOffset actionOffset = flags & lsfPerformAction;
  60
  61     if (actionOffset != 0) {
  62         const LigatureActionEntry *ap = (const LigatureActionEntry *) ((char *) &ligatureSubstitutionHeader->stHeader + ligActionOffset) + ligActionIndex;
  63         const TTGlyphID *ligatureTable = (const TTGlyphID *) ((char *) &ligatureSubstitutionHeader->stHeader + ligatureOffset);
  64         LigatureActionEntry action;
  65         le_int32 offset, i = 0;
  66         le_int32 stack[nComponents];
  67         le_int16 mm = -1;
  68
  69         const le_uint16 *componentTable = (const le_uint16 *)((char *) &ligatureSubstitutionHeader->stHeader + componentOffset);
  70
  71         do {
  72             le_uint32 componentGlyph = componentStack[m--]; // pop off
  73
  74             action = SWAPL(*ap++);
  75
  76             if (m < 0) {
  77                 m = nComponents - 1;
  78             }
  79
  80             offset = action & lafComponentOffsetMask;
  81             if (offset != 0) {
  82
  83                 i += SWAPW(componentTable[LE_GET_GLYPH(glyphStorage[componentGlyph]) + (SignExtend(offset, lafComponentOffsetMask))]);
  84
  85                 if (action & (lafLast | lafStore))  {
  86                     TTGlyphID ligatureGlyph = SWAPW(ligatureTable[i]);
  87                     glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], ligatureGlyph);
  88                     stack[++mm] = componentGlyph;
  89                     i = 0;
  90                 } else {
  91                     glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], 0xFFFF);
  92                 }
  93             }
  94         } while (!(action & lafLast));
  95
  96         while (mm >= 0) {
  97             if (++m >= nComponents) {
  98                 m = 0;
  99             }
 100
 101             componentStack[m] = stack[mm--];
 102         }
 103     }
 104
 105     if (!(flags & lsfDontAdvance)) {
 106         currGlyph += dir;
 107     }
 108
 109     return nextStateIndex;
 110 }
 111
 112 void LigatureSubstitutionProcessor2::endStateTable()
 113 {
 114 }
 115
 116 U_NAMESPACE_END