cmaps.cpp revision c73f511526464f8e56c242df80552e9b0d94ae3d 
1/*
2 ****************************************************************************** *
3 *
4 *   Copyright (C) 1999-2003, International Business Machines
5 *   Corporation and others.  All Rights Reserved.
6 *
7 ****************************************************************************** *
8 *   file name:  cmaps.cpp
9 *
10 *   created on: ??/??/2001
11 *   created by: Eric R. Mader
12 */
13
14#include "layout/LETypes.h"
15#include "layout/LESwaps.h"
16
17#include "sfnt.h"
18#include "cmaps.h"
19
20#define SWAPU16(code) ((LEUnicode16) SWAPW(code))
21#define SWAPU32(code) ((LEUnicode32) SWAPL(code))
22
23//
24// Finds the high bit by binary searching
25// through the bits in value.
26//
27le_uint8 highBit(le_uint32 value)
28{
29    le_uint8 bit = 0;
30
31    if (value >= 1 << 16) {
32        value >>= 16;
33        bit += 16;
34    }
35
36    if (value >= 1 << 8) {
37        value >>= 8;
38        bit += 8;
39    }
40
41    if (value >= 1 << 4) {
42        value >>= 4;
43        bit += 4;
44    }
45
46    if (value >= 1 << 2) {
47        value >>= 2;
48        bit += 2;
49    }
50
51    if (value >= 1 << 1) {
52        value >>= 1;
53        bit += 1;
54    }
55
56    return bit;
57}
58
59CMAPMapper *CMAPMapper::createUnicodeMapper(const CMAPTable *cmap)
60{
61    le_uint16 i;
62    le_uint16 nSubtables = SWAPW(cmap->numberSubtables);
63    const CMAPEncodingSubtable *subtable = NULL;
64    le_uint32 offset1 = 0, offset10 = 0;
65
66    for (i = 0; i < nSubtables; i += 1) {
67        const CMAPEncodingSubtableHeader *esh = &cmap->encodingSubtableHeaders[i];
68
69        if (SWAPW(esh->platformID) == 3) {
70            switch (SWAPW(esh->platformSpecificID)) {
71            case 1:
72                offset1 = SWAPL(esh->encodingOffset);
73                break;
74
75            case 10:
76                offset10 = SWAPL(esh->encodingOffset);
77                break;
78            }
79        }
80    }
81
82
83    if (offset10 != 0)
84    {
85        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset10);
86    } else if (offset1 != 0) {
87        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset1);
88    } else {
89        return NULL;
90    }
91
92    switch (SWAPW(subtable->format)) {
93    case 4:
94        return new CMAPFormat4Mapper(cmap, (const CMAPFormat4Encoding *) subtable);
95
96    case 12:
97    {
98        const CMAPFormat12Encoding *encoding = (const CMAPFormat12Encoding *) subtable;
99
100        return new CMAPGroupMapper(cmap, encoding->groups, SWAPL(encoding->nGroups));
101    }
102
103    default:
104        break;
105    }
106
107    return NULL;
108}
109
110CMAPFormat4Mapper::CMAPFormat4Mapper(const CMAPTable *cmap, const CMAPFormat4Encoding *header)
111    : CMAPMapper(cmap)
112{
113    le_uint16 segCount = SWAPW(header->segCountX2) / 2;
114
115    fEntrySelector = SWAPW(header->entrySelector);
116    fRangeShift = SWAPW(header->rangeShift) / 2;
117    fEndCodes = &header->endCodes[0];
118    fStartCodes = &header->endCodes[segCount + 1]; // + 1 for reservedPad...
119    fIdDelta = &fStartCodes[segCount];
120    fIdRangeOffset = &fIdDelta[segCount];
121}
122
123LEGlyphID CMAPFormat4Mapper::unicodeToGlyph(LEUnicode32 unicode32) const
124{
125    if (unicode32 >= 0x10000) {
126        return 0;
127    }
128
129    LEUnicode16 unicode = (LEUnicode16) unicode32;
130    le_uint16 index = 0;
131    le_uint16 probe = 1 << fEntrySelector;
132    TTGlyphID result = 0;
133
134    if (SWAPU16(fStartCodes[fRangeShift]) <= unicode) {
135        index = fRangeShift;
136    }
137
138    while (probe > (1 << 0)) {
139        probe >>= 1;
140
141        if (SWAPU16(fStartCodes[index + probe]) <= unicode) {
142            index += probe;
143        }
144    }
145
146    if (unicode >= SWAPU16(fStartCodes[index]) && unicode <= SWAPU16(fEndCodes[index])) {
147        if (fIdRangeOffset[index] == 0) {
148            result = (TTGlyphID) unicode;
149        } else {
150            le_uint16 offset = unicode - SWAPU16(fStartCodes[index]);
151            le_uint16 rangeOffset = SWAPW(fIdRangeOffset[index]);
152            le_uint16 *glyphIndexTable = (le_uint16 *) ((char *) &fIdRangeOffset[index] + rangeOffset);
153
154            result = SWAPW(glyphIndexTable[offset]);
155        }
156
157        result += SWAPW(fIdDelta[index]);
158    } else {
159        result = 0;
160    }
161
162    return LE_SET_GLYPH(0, result);
163}
164
165CMAPFormat4Mapper::~CMAPFormat4Mapper()
166{
167    // parent destructor does it all
168}
169
170CMAPGroupMapper::CMAPGroupMapper(const CMAPTable *cmap, const CMAPGroup *groups, le_uint32 nGroups)
171    : CMAPMapper(cmap), fGroups(groups)
172{
173    le_uint8 bit = highBit(nGroups);
174    fPower = 1 << bit;
175    fRangeOffset = nGroups - fPower;
176}
177
178LEGlyphID CMAPGroupMapper::unicodeToGlyph(LEUnicode32 unicode32) const
179{
180    le_int32 probe = fPower;
181    le_int32 range = 0;
182
183    if (SWAPU32(fGroups[fRangeOffset].startCharCode) <= unicode32) {
184        range = fRangeOffset;
185    }
186
187    while (probe > (1 << 0)) {
188        probe >>= 1;
189
190        if (SWAPU32(fGroups[range + probe].startCharCode) <= unicode32) {
191            range += probe;
192        }
193    }
194
195    if (SWAPU32(fGroups[range].startCharCode) <= unicode32 && SWAPU32(fGroups[range].endCharCode) >= unicode32) {
196        return (LEGlyphID) (SWAPU32(fGroups[range].startGlyphCode) + unicode32 - SWAPU32(fGroups[range].startCharCode));
197    }
198
199    return 0;
200}
201
202CMAPGroupMapper::~CMAPGroupMapper()
203{
204    // parent destructor does it all
205}
206
207