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      1 /*
      2  *
      3  * (C) Copyright IBM Corp. 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 "SubtableProcessor.h"
     12 #include "StateTableProcessor.h"
     13 #include "LigatureSubstProc.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(LigatureSubstitutionProcessor)
     24 
     25   LigatureSubstitutionProcessor::LigatureSubstitutionProcessor(const LEReferenceTo<MorphSubtableHeader> &morphSubtableHeader, LEErrorCode &success)
     26 : StateTableProcessor(morphSubtableHeader, success), ligatureSubstitutionHeader(morphSubtableHeader, success)
     27 {
     28     if(LE_FAILURE(success)) return;
     29     ligatureActionTableOffset = SWAPW(ligatureSubstitutionHeader->ligatureActionTableOffset);
     30     componentTableOffset = SWAPW(ligatureSubstitutionHeader->componentTableOffset);
     31     ligatureTableOffset = SWAPW(ligatureSubstitutionHeader->ligatureTableOffset);
     32 
     33     entryTable = LEReferenceToArrayOf<LigatureSubstitutionStateEntry>(stHeader, success, entryTableOffset, LE_UNBOUNDED_ARRAY);
     34 }
     35 
     36 LigatureSubstitutionProcessor::~LigatureSubstitutionProcessor()
     37 {
     38 }
     39 
     40 void LigatureSubstitutionProcessor::beginStateTable()
     41 {
     42     m = -1;
     43 }
     44 
     45 ByteOffset LigatureSubstitutionProcessor::processStateEntry(LEGlyphStorage &glyphStorage, le_int32 &currGlyph, EntryTableIndex index)
     46 {
     47   LEErrorCode success = LE_NO_ERROR;
     48   const LigatureSubstitutionStateEntry *entry = entryTable.getAlias(index, success);
     49 
     50     ByteOffset newState = SWAPW(entry->newStateOffset);
     51     le_int16 flags = SWAPW(entry->flags);
     52 
     53     if (flags & lsfSetComponent) {
     54         if (++m >= nComponents) {
     55             m = 0;
     56         }
     57 
     58         componentStack[m] = currGlyph;
     59     } else if ( m == -1) {
     60         // bad font- skip this glyph.
     61         currGlyph++;
     62         return newState;
     63     }
     64 
     65     ByteOffset actionOffset = flags & lsfActionOffsetMask;
     66 
     67     if (actionOffset != 0) {
     68       LEReferenceTo<LigatureActionEntry> ap(stHeader, success, actionOffset);
     69         LigatureActionEntry action;
     70         le_int32 offset, i = 0;
     71         le_int32 stack[nComponents];
     72         le_int16 mm = -1;
     73 
     74         do {
     75             le_uint32 componentGlyph = componentStack[m--];
     76 
     77             action = SWAPL(*ap.getAlias());
     78             ap.addObject(success); // ap++
     79 
     80             if (m < 0) {
     81                 m = nComponents - 1;
     82             }
     83 
     84             offset = action & lafComponentOffsetMask;
     85             if (offset != 0) {
     86               LEReferenceToArrayOf<le_int16> offsetTable(stHeader, success, 2 * SignExtend(offset, lafComponentOffsetMask), LE_UNBOUNDED_ARRAY);
     87 
     88               if(LE_FAILURE(success)) {
     89                   currGlyph++;
     90                   LE_DEBUG_BAD_FONT("off end of ligature substitution header");
     91                   return newState; // get out! bad font
     92               }
     93               if(componentGlyph > (le_uint32)glyphStorage.getGlyphCount()) {
     94                 LE_DEBUG_BAD_FONT("preposterous componentGlyph");
     95                 currGlyph++;
     96                 return newState; // get out! bad font
     97               }
     98               i += SWAPW(offsetTable.getObject(LE_GET_GLYPH(glyphStorage[componentGlyph]), success));
     99 
    100                 if (action & (lafLast | lafStore))  {
    101                   LEReferenceTo<TTGlyphID> ligatureOffset(stHeader, success, i);
    102                   TTGlyphID ligatureGlyph = SWAPW(*ligatureOffset.getAlias());
    103 
    104                   glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], ligatureGlyph);
    105                   if(mm==nComponents) {
    106                     LE_DEBUG_BAD_FONT("exceeded nComponents");
    107                     mm--; // don't overrun the stack.
    108                   }
    109                   stack[++mm] = componentGlyph;
    110                   i = 0;
    111                 } else {
    112                   glyphStorage[componentGlyph] = LE_SET_GLYPH(glyphStorage[componentGlyph], 0xFFFF);
    113                 }
    114             }
    115 #if LE_ASSERT_BAD_FONT
    116             if(m<0) {
    117               LE_DEBUG_BAD_FONT("m<0")
    118             }
    119 #endif
    120         } while (!(action & lafLast)  && (m>=0) ); // stop if last bit is set, or if run out of items
    121 
    122         while (mm >= 0) {
    123           if (++m >= nComponents) {
    124             m = 0;
    125           }
    126 
    127           componentStack[m] = stack[mm--];
    128         }
    129     }
    130 
    131     if (!(flags & lsfDontAdvance)) {
    132         // should handle reverse too!
    133         currGlyph += 1;
    134     }
    135 
    136     return newState;
    137 }
    138 
    139 void LigatureSubstitutionProcessor::endStateTable()
    140 {
    141 }
    142 
    143 U_NAMESPACE_END
    144