1/***************************************************************************
2*
3*   Copyright (C) 1998-2003, International Business Machines
4*   Corporation and others.  All Rights Reserved.
5*
6************************************************************************/
7
8#include "layout/LETypes.h"
9#include "layout/LESwaps.h"
10
11#include "sfnt.h"
12#include "cmaps.h"
13
14#define SWAPU16(code) ((LEUnicode16) SWAPW(code))
15#define SWAPU32(code) ((LEUnicode32) SWAPL(code))
16
17//
18// Finds the high bit by binary searching
19// through the bits in value.
20//
21static inline le_int8 highBit(le_uint32 value)
22{
23    le_uint8 bit = 0;
24
25    if (value >= 1 << 16) {
26        value >>= 16;
27        bit += 16;
28    }
29
30    if (value >= 1 << 8) {
31        value >>= 8;
32        bit += 8;
33    }
34
35    if (value >= 1 << 4) {
36        value >>= 4;
37        bit += 4;
38    }
39
40    if (value >= 1 << 2) {
41        value >>= 2;
42        bit += 2;
43    }
44
45    if (value >= 1 << 1) {
46        value >>= 1;
47        bit += 1;
48    }
49
50    return bit;
51}
52
53CMAPMapper *CMAPMapper::createUnicodeMapper(const CMAPTable *cmap)
54{
55    le_uint16 i;
56    le_uint16 nSubtables = SWAPW(cmap->numberSubtables);
57    const CMAPEncodingSubtable *subtable = NULL;
58    le_uint32 offset1 = 0, offset10 = 0;
59
60    for (i = 0; i < nSubtables; i += 1) {
61        const CMAPEncodingSubtableHeader *esh = &cmap->encodingSubtableHeaders[i];
62
63        if (SWAPW(esh->platformID) == 3) {
64            switch (SWAPW(esh->platformSpecificID)) {
65            case 1:
66                offset1 = SWAPL(esh->encodingOffset);
67                break;
68
69            case 10:
70                offset10 = SWAPL(esh->encodingOffset);
71                break;
72            }
73        }
74    }
75
76
77    if (offset10 != 0)
78    {
79        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset10);
80    } else if (offset1 != 0) {
81        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset1);
82    } else {
83        return NULL;
84    }
85
86    switch (SWAPW(subtable->format)) {
87    case 4:
88        return new CMAPFormat4Mapper(cmap, (const CMAPFormat4Encoding *) subtable);
89
90    case 12:
91    {
92        const CMAPFormat12Encoding *encoding = (const CMAPFormat12Encoding *) subtable;
93
94        return new CMAPGroupMapper(cmap, encoding->groups, SWAPL(encoding->nGroups));
95    }
96
97    default:
98        break;
99    }
100
101    return NULL;
102}
103
104CMAPFormat4Mapper::CMAPFormat4Mapper(const CMAPTable *cmap, const CMAPFormat4Encoding *header)
105    : CMAPMapper(cmap)
106{
107    le_uint16 segCount = SWAPW(header->segCountX2) / 2;
108
109    fEntrySelector = SWAPW(header->entrySelector);
110    fRangeShift = SWAPW(header->rangeShift) / 2;
111    fEndCodes = &header->endCodes[0];
112    fStartCodes = &header->endCodes[segCount + 1]; // + 1 for reservedPad...
113    fIdDelta = &fStartCodes[segCount];
114    fIdRangeOffset = &fIdDelta[segCount];
115}
116
117LEGlyphID CMAPFormat4Mapper::unicodeToGlyph(LEUnicode32 unicode32) const
118{
119    if (unicode32 >= 0x10000) {
120        return 0;
121    }
122
123    LEUnicode16 unicode = (LEUnicode16) unicode32;
124    le_uint16 index = 0;
125    le_uint16 probe = 1 << fEntrySelector;
126    TTGlyphID result = 0;
127
128    if (SWAPU16(fStartCodes[fRangeShift]) <= unicode) {
129        index = fRangeShift;
130    }
131
132    while (probe > (1 << 0)) {
133        probe >>= 1;
134
135        if (SWAPU16(fStartCodes[index + probe]) <= unicode) {
136            index += probe;
137        }
138    }
139
140    if (unicode >= SWAPU16(fStartCodes[index]) && unicode <= SWAPU16(fEndCodes[index])) {
141        if (fIdRangeOffset[index] == 0) {
142            result = (TTGlyphID) unicode;
143        } else {
144            le_uint16 offset = unicode - SWAPU16(fStartCodes[index]);
145            le_uint16 rangeOffset = SWAPW(fIdRangeOffset[index]);
146            le_uint16 *glyphIndexTable = (le_uint16 *) ((char *) &fIdRangeOffset[index] + rangeOffset);
147
148            result = SWAPW(glyphIndexTable[offset]);
149        }
150
151        result += SWAPW(fIdDelta[index]);
152    } else {
153        result = 0;
154    }
155
156    return LE_SET_GLYPH(0, result);
157}
158
159CMAPFormat4Mapper::~CMAPFormat4Mapper()
160{
161    // parent destructor does it all
162}
163
164CMAPGroupMapper::CMAPGroupMapper(const CMAPTable *cmap, const CMAPGroup *groups, le_uint32 nGroups)
165    : CMAPMapper(cmap), fGroups(groups)
166{
167    le_uint8 bit = highBit(nGroups);
168    fPower = 1 << bit;
169    fRangeOffset = nGroups - fPower;
170}
171
172LEGlyphID CMAPGroupMapper::unicodeToGlyph(LEUnicode32 unicode32) const
173{
174    le_int32 probe = fPower;
175    le_int32 range = 0;
176
177    if (SWAPU32(fGroups[fRangeOffset].startCharCode) <= unicode32) {
178        range = fRangeOffset;
179    }
180
181    while (probe > (1 << 0)) {
182        probe >>= 1;
183
184        if (SWAPU32(fGroups[range + probe].startCharCode) <= unicode32) {
185            range += probe;
186        }
187    }
188
189    if (SWAPU32(fGroups[range].startCharCode) <= unicode32 && SWAPU32(fGroups[range].endCharCode) >= unicode32) {
190        return (LEGlyphID) (SWAPU32(fGroups[range].startGlyphCode) + unicode32 - SWAPU32(fGroups[range].startCharCode));
191    }
192
193    return 0;
194}
195
196CMAPGroupMapper::~CMAPGroupMapper()
197{
198    // parent destructor does it all
199}
200
201