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
17U_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
23UOBJECT_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
36LigatureSubstitutionProcessor::~LigatureSubstitutionProcessor()
37{
38}
39
40void LigatureSubstitutionProcessor::beginStateTable()
41{
42    m = -1;
43}
44
45ByteOffset 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
139void LigatureSubstitutionProcessor::endStateTable()
140{
141}
142
143U_NAMESPACE_END
144