icuSources/layout/LigatureSubstProc2.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp and Others. 1998-2014 - 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 LEReferenceTo<MorphSubtableHeader2> &morphSubtableHeader, LEErrorCode &success)
  26   : StateTableProcessor2(morphSubtableHeader, success),
  27   ligActionOffset(0),
  28   componentOffset(0), ligatureOffset(0),  entryTable(), ligatureSubstitutionHeader(morphSubtableHeader, success)
  29 {
  30     if (LE_FAILURE(success)) return;
  31
  32     ligActionOffset = SWAPL(ligatureSubstitutionHeader->ligActionOffset);
  33     componentOffset = SWAPL(ligatureSubstitutionHeader->componentOffset);
  34     ligatureOffset = SWAPL(ligatureSubstitutionHeader->ligatureOffset);
  35
  36     entryTable = LEReferenceToArrayOf<LigatureSubstitutionStateEntry2>(stHeader, success, entryTableOffset, LE_UNBOUNDED_ARRAY);
  37 }
  38
  39 LigatureSubstitutionProcessor2::~LigatureSubstitutionProcessor2()
  40 {
  41 }
  42
  43 void LigatureSubstitutionProcessor2::beginStateTable()
  44 {
  45     m = -1;
  46 }
  47
  48 le_uint16 LigatureSubstitutionProcessor2::processStateEntry(LEGlyphStorage &glyphStorage, le_int32 &currGlyph, EntryTableIndex2 index, LEErrorCode &success)
  49 {
  50     const LigatureSubstitutionStateEntry2 *entry = entryTable.getAlias(index, success);
  51     if(LE_FAILURE(success)) return 0;
  52
  53     le_uint16 nextStateIndex = SWAPW(entry->nextStateIndex);
  54     le_uint16 flags = SWAPW(entry->entryFlags);
  55     le_uint16 ligActionIndex = SWAPW(entry->ligActionIndex);
  56
  57     if (flags & lsfSetComponent) {
  58         if (++m >= nComponents) {
  59             m = 0;
  60         }
  61         componentStack[m] = currGlyph;
  62     } else if ( m == -1) {
  63         // bad font- skip this glyph.
  64         //LE_DEBUG_BAD_FONT("m==-1 (componentCount went negative)")
  65         currGlyph+= dir;
  66         return nextStateIndex;
  67     }
  68
  69     ByteOffset actionOffset = flags & lsfPerformAction;
  70
  71     if (actionOffset != 0) {
  72         LEReferenceTo<LigatureActionEntry> ap(stHeader, success, ligActionOffset); // byte offset
  73         ap.addObject(ligActionIndex - 1, success);  // index offset ( one before the actual start, because we will pre-increment)
  74         LEReferenceToArrayOf<TTGlyphID> ligatureTable(stHeader, success, ligatureOffset, LE_UNBOUNDED_ARRAY);
  75         LigatureActionEntry action;
  76         le_int32 offset, i = 0;
  77         le_int32 stack[nComponents];
  78         le_int16 mm = -1;
  79
  80         LEReferenceToArrayOf<le_uint16> componentTable(stHeader, success, componentOffset, LE_UNBOUNDED_ARRAY);
  81         if(LE_FAILURE(success)) {
  82           currGlyph+= dir;
  83           return nextStateIndex; // get out! bad font
  84         }
  85
  86         do {
  87             le_int32 componentGlyph = componentStack[m--]; // pop off
  88
  89             ap.addObject(success);
  90             action = SWAPL(*ap.getAlias());
  91
  92             if (m < 0) {
  93                 m = nComponents - 1;
  94             }
  95
  96             offset = action & lafComponentOffsetMask;
  97             if (offset != 0) {
  98                 if(componentGlyph > glyphStorage.getGlyphCount() || componentGlyph < 0) {
  99                   LE_DEBUG_BAD_FONT("preposterous componentGlyph");
 100                   currGlyph+= dir;
 101                   return nextStateIndex; // get out! bad font
 102                 }
 103                 i += SWAPW(componentTable(LE_GET_GLYPH(glyphStorage[componentGlyph]) + (SignExtend(offset, lafComponentOffsetMask)),success));
 104
 105                 if (action & (lafLast | lafStore))  {
 106                   TTGlyphID ligatureGlyph = SWAPW(ligatureTable(i,success));
 107                     glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], ligatureGlyph);
 108                     if(mm==nComponents) {
 109                       LE_DEBUG_BAD_FONT("exceeded nComponents");
 110                       mm--; // don't overrun the stack.
 111                     }
 112                     stack[++mm] = componentGlyph;
 113                     i = 0;
 114                 } else {
 115                     glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], 0xFFFF);
 116                 }
 117             }
 118 #if LE_ASSERT_BAD_FONT
 119             if(m<0) {
 120               LE_DEBUG_BAD_FONT("m<0")
 121             }
 122 #endif
 123         } while (!(action & lafLast) && (m>=0) ); // stop if last bit is set, or if run out of items
 124
 125         while (mm >= 0) {
 126             if (++m >= nComponents) {
 127                 m = 0;
 128             }
 129
 130             componentStack[m] = stack[mm--];
 131         }
 132     }
 133
 134     if (!(flags & lsfDontAdvance)) {
 135         currGlyph += dir;
 136     }
 137
 138     return nextStateIndex;
 139 }
 140
 141 void LigatureSubstitutionProcessor2::endStateTable()
 142 {
 143 }
 144
 145 U_NAMESPACE_END