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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "gdef.h" | |
6 | |
7 #include <limits> | |
8 #include <vector> | |
9 | |
10 #include "gpos.h" | |
11 #include "gsub.h" | |
12 #include "layout.h" | |
13 #include "maxp.h" | |
14 | |
15 // GDEF - The Glyph Definition Table | |
16 // http://www.microsoft.com/typography/otspec/gdef.htm | |
17 | |
18 #define TABLE_NAME "GDEF" | |
19 | |
20 namespace { | |
21 | |
22 // The maximum class value in class definition tables. | |
23 const uint16_t kMaxClassDefValue = 0xFFFF; | |
24 // The maximum class value in the glyph class definision table. | |
25 const uint16_t kMaxGlyphClassDefValue = 4; | |
26 // The maximum format number of caret value tables. | |
27 // We don't support format 3 for now. See the comment in | |
28 // ParseLigCaretListTable() for the reason. | |
29 const uint16_t kMaxCaretValueFormat = 2; | |
30 | |
31 bool ParseGlyphClassDefTable(ots::OpenTypeFile *file, const uint8_t *data, | |
32 size_t length, const uint16_t num_glyphs) { | |
33 return ots::ParseClassDefTable(file, data, length, num_glyphs, | |
34 kMaxGlyphClassDefValue); | |
35 } | |
36 | |
37 bool ParseAttachListTable(ots::OpenTypeFile *file, const uint8_t *data, | |
38 size_t length, const uint16_t num_glyphs) { | |
39 ots::Buffer subtable(data, length); | |
40 | |
41 uint16_t offset_coverage = 0; | |
42 uint16_t glyph_count = 0; | |
43 if (!subtable.ReadU16(&offset_coverage) || | |
44 !subtable.ReadU16(&glyph_count)) { | |
45 return OTS_FAILURE_MSG("Failed to read gdef header"); | |
46 } | |
47 const unsigned attach_points_end = | |
48 2 * static_cast<unsigned>(glyph_count) + 4; | |
49 if (attach_points_end > std::numeric_limits<uint16_t>::max()) { | |
50 return OTS_FAILURE_MSG("Bad glyph count in gdef"); | |
51 } | |
52 if (offset_coverage == 0 || offset_coverage >= length || | |
53 offset_coverage < attach_points_end) { | |
54 return OTS_FAILURE_MSG("Bad coverage offset %d", offset_coverage); | |
55 } | |
56 if (glyph_count > num_glyphs) { | |
57 return OTS_FAILURE_MSG("Bad glyph count %u", glyph_count); | |
58 } | |
59 | |
60 std::vector<uint16_t> attach_points; | |
61 attach_points.resize(glyph_count); | |
62 for (unsigned i = 0; i < glyph_count; ++i) { | |
63 if (!subtable.ReadU16(&attach_points[i])) { | |
64 return OTS_FAILURE_MSG("Can't read attachment point %d", i); | |
65 } | |
66 if (attach_points[i] >= length || | |
67 attach_points[i] < attach_points_end) { | |
68 return OTS_FAILURE_MSG("Bad attachment point %d of %d", i, attach_points[i
]); | |
69 } | |
70 } | |
71 | |
72 // Parse coverage table | |
73 if (!ots::ParseCoverageTable(file, data + offset_coverage, | |
74 length - offset_coverage, num_glyphs)) { | |
75 return OTS_FAILURE_MSG("Bad coverage table"); | |
76 } | |
77 | |
78 // Parse attach point table | |
79 for (unsigned i = 0; i < attach_points.size(); ++i) { | |
80 subtable.set_offset(attach_points[i]); | |
81 uint16_t point_count = 0; | |
82 if (!subtable.ReadU16(&point_count)) { | |
83 return OTS_FAILURE_MSG("Can't read point count %d", i); | |
84 } | |
85 if (point_count == 0) { | |
86 return OTS_FAILURE_MSG("zero point count %d", i); | |
87 } | |
88 uint16_t last_point_index = 0; | |
89 uint16_t point_index = 0; | |
90 for (unsigned j = 0; j < point_count; ++j) { | |
91 if (!subtable.ReadU16(&point_index)) { | |
92 return OTS_FAILURE_MSG("Can't read point index %d in point %d", j, i); | |
93 } | |
94 // Contour point indeces are in increasing numerical order | |
95 if (last_point_index != 0 && last_point_index >= point_index) { | |
96 return OTS_FAILURE_MSG("bad contour indeces: %u >= %u", | |
97 last_point_index, point_index); | |
98 } | |
99 last_point_index = point_index; | |
100 } | |
101 } | |
102 return true; | |
103 } | |
104 | |
105 bool ParseLigCaretListTable(ots::OpenTypeFile *file, const uint8_t *data, | |
106 size_t length, const uint16_t num_glyphs) { | |
107 ots::Buffer subtable(data, length); | |
108 uint16_t offset_coverage = 0; | |
109 uint16_t lig_glyph_count = 0; | |
110 if (!subtable.ReadU16(&offset_coverage) || | |
111 !subtable.ReadU16(&lig_glyph_count)) { | |
112 return OTS_FAILURE_MSG("Can't read caret structure"); | |
113 } | |
114 const unsigned lig_glyphs_end = | |
115 2 * static_cast<unsigned>(lig_glyph_count) + 4; | |
116 if (lig_glyphs_end > std::numeric_limits<uint16_t>::max()) { | |
117 return OTS_FAILURE_MSG("Bad caret structure"); | |
118 } | |
119 if (offset_coverage == 0 || offset_coverage >= length || | |
120 offset_coverage < lig_glyphs_end) { | |
121 return OTS_FAILURE_MSG("Bad caret coverate offset %d", offset_coverage); | |
122 } | |
123 if (lig_glyph_count > num_glyphs) { | |
124 return OTS_FAILURE_MSG("bad ligature glyph count: %u", lig_glyph_count); | |
125 } | |
126 | |
127 std::vector<uint16_t> lig_glyphs; | |
128 lig_glyphs.resize(lig_glyph_count); | |
129 for (unsigned i = 0; i < lig_glyph_count; ++i) { | |
130 if (!subtable.ReadU16(&lig_glyphs[i])) { | |
131 return OTS_FAILURE_MSG("Can't read ligature glyph location %d", i); | |
132 } | |
133 if (lig_glyphs[i] >= length || lig_glyphs[i] < lig_glyphs_end) { | |
134 return OTS_FAILURE_MSG("Bad ligature glyph location %d in glyph %d", lig_g
lyphs[i], i); | |
135 } | |
136 } | |
137 | |
138 // Parse coverage table | |
139 if (!ots::ParseCoverageTable(file, data + offset_coverage, | |
140 length - offset_coverage, num_glyphs)) { | |
141 return OTS_FAILURE_MSG("Can't parse caret coverage table"); | |
142 } | |
143 | |
144 // Parse ligature glyph table | |
145 for (unsigned i = 0; i < lig_glyphs.size(); ++i) { | |
146 subtable.set_offset(lig_glyphs[i]); | |
147 uint16_t caret_count = 0; | |
148 if (!subtable.ReadU16(&caret_count)) { | |
149 return OTS_FAILURE_MSG("Can't read caret count for glyph %d", i); | |
150 } | |
151 if (caret_count == 0) { | |
152 return OTS_FAILURE_MSG("bad caret value count: %u", caret_count); | |
153 } | |
154 | |
155 std::vector<uint16_t> caret_value_offsets; | |
156 caret_value_offsets.resize(caret_count); | |
157 unsigned caret_value_offsets_end = 2 * static_cast<unsigned>(caret_count) +
2; | |
158 for (unsigned j = 0; j < caret_count; ++j) { | |
159 if (!subtable.ReadU16(&caret_value_offsets[j])) { | |
160 return OTS_FAILURE_MSG("Can't read caret offset %d for glyph %d", j, i); | |
161 } | |
162 if (caret_value_offsets[j] >= length || caret_value_offsets[j] < caret_val
ue_offsets_end) { | |
163 return OTS_FAILURE_MSG("Bad caret offset %d for caret %d glyph %d", care
t_value_offsets[j], j, i); | |
164 } | |
165 } | |
166 | |
167 // Parse caret values table | |
168 for (unsigned j = 0; j < caret_count; ++j) { | |
169 subtable.set_offset(lig_glyphs[i] + caret_value_offsets[j]); | |
170 uint16_t caret_format = 0; | |
171 if (!subtable.ReadU16(&caret_format)) { | |
172 return OTS_FAILURE_MSG("Can't read caret values table %d in glyph %d", j
, i); | |
173 } | |
174 // TODO(bashi): We only support caret value format 1 and 2 for now | |
175 // because there are no fonts which contain caret value format 3 | |
176 // as far as we investigated. | |
177 if (caret_format == 0 || caret_format > kMaxCaretValueFormat) { | |
178 return OTS_FAILURE_MSG("bad caret value format: %u", caret_format); | |
179 } | |
180 // CaretValueFormats contain a 2-byte field which could be | |
181 // arbitrary value. | |
182 if (!subtable.Skip(2)) { | |
183 return OTS_FAILURE_MSG("Bad caret value table structure %d in glyph %d",
j, i); | |
184 } | |
185 } | |
186 } | |
187 return true; | |
188 } | |
189 | |
190 bool ParseMarkAttachClassDefTable(ots::OpenTypeFile *file, const uint8_t *data, | |
191 size_t length, const uint16_t num_glyphs) { | |
192 return ots::ParseClassDefTable(file, data, length, num_glyphs, kMaxClassDefVal
ue); | |
193 } | |
194 | |
195 bool ParseMarkGlyphSetsDefTable(ots::OpenTypeFile *file, const uint8_t *data, | |
196 size_t length, const uint16_t num_glyphs) { | |
197 ots::Buffer subtable(data, length); | |
198 uint16_t format = 0; | |
199 uint16_t mark_set_count = 0; | |
200 if (!subtable.ReadU16(&format) || | |
201 !subtable.ReadU16(&mark_set_count)) { | |
202 return OTS_FAILURE_MSG("Can' read mark glyph table structure"); | |
203 } | |
204 if (format != 1) { | |
205 return OTS_FAILURE_MSG("bad mark glyph set table format: %u", format); | |
206 } | |
207 | |
208 const unsigned mark_sets_end = 2 * static_cast<unsigned>(mark_set_count) + 4; | |
209 if (mark_sets_end > std::numeric_limits<uint16_t>::max()) { | |
210 return OTS_FAILURE_MSG("Bad mark_set %d", mark_sets_end); | |
211 } | |
212 for (unsigned i = 0; i < mark_set_count; ++i) { | |
213 uint32_t offset_coverage = 0; | |
214 if (!subtable.ReadU32(&offset_coverage)) { | |
215 return OTS_FAILURE_MSG("Can't read covrage location for mark set %d", i); | |
216 } | |
217 if (offset_coverage >= length || | |
218 offset_coverage < mark_sets_end) { | |
219 return OTS_FAILURE_MSG("Bad coverage location %d for mark set %d", offset_
coverage, i); | |
220 } | |
221 if (!ots::ParseCoverageTable(file, data + offset_coverage, | |
222 length - offset_coverage, num_glyphs)) { | |
223 return OTS_FAILURE_MSG("Failed to parse coverage table for mark set %d", i
); | |
224 } | |
225 } | |
226 file->gdef->num_mark_glyph_sets = mark_set_count; | |
227 return true; | |
228 } | |
229 | |
230 } // namespace | |
231 | |
232 #define DROP_THIS_TABLE(msg_) \ | |
233 do { \ | |
234 OTS_FAILURE_MSG(msg_ ", table discarded"); \ | |
235 file->gdef->data = 0; \ | |
236 file->gdef->length = 0; \ | |
237 } while (0) | |
238 | |
239 namespace ots { | |
240 | |
241 bool ots_gdef_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { | |
242 // Grab the number of glyphs in the file from the maxp table to check | |
243 // GlyphIDs in GDEF table. | |
244 if (!file->maxp) { | |
245 return OTS_FAILURE_MSG("No maxp table in font, needed by GDEF"); | |
246 } | |
247 const uint16_t num_glyphs = file->maxp->num_glyphs; | |
248 | |
249 Buffer table(data, length); | |
250 | |
251 OpenTypeGDEF *gdef = new OpenTypeGDEF; | |
252 file->gdef = gdef; | |
253 | |
254 uint32_t version = 0; | |
255 if (!table.ReadU32(&version)) { | |
256 DROP_THIS_TABLE("Incomplete table"); | |
257 return true; | |
258 } | |
259 if (version < 0x00010000 || version == 0x00010001) { | |
260 DROP_THIS_TABLE("Bad version"); | |
261 return true; | |
262 } | |
263 | |
264 if (version >= 0x00010002) { | |
265 gdef->version_2 = true; | |
266 } | |
267 | |
268 uint16_t offset_glyph_class_def = 0; | |
269 uint16_t offset_attach_list = 0; | |
270 uint16_t offset_lig_caret_list = 0; | |
271 uint16_t offset_mark_attach_class_def = 0; | |
272 if (!table.ReadU16(&offset_glyph_class_def) || | |
273 !table.ReadU16(&offset_attach_list) || | |
274 !table.ReadU16(&offset_lig_caret_list) || | |
275 !table.ReadU16(&offset_mark_attach_class_def)) { | |
276 DROP_THIS_TABLE("Incomplete table"); | |
277 return true; | |
278 } | |
279 uint16_t offset_mark_glyph_sets_def = 0; | |
280 if (gdef->version_2) { | |
281 if (!table.ReadU16(&offset_mark_glyph_sets_def)) { | |
282 DROP_THIS_TABLE("Incomplete table"); | |
283 return true; | |
284 } | |
285 } | |
286 | |
287 unsigned gdef_header_end = 4 + 4 * 2; | |
288 if (gdef->version_2) | |
289 gdef_header_end += 2; | |
290 | |
291 // Parse subtables | |
292 if (offset_glyph_class_def) { | |
293 if (offset_glyph_class_def >= length || | |
294 offset_glyph_class_def < gdef_header_end) { | |
295 DROP_THIS_TABLE("Invalid offset to glyph classes"); | |
296 return true; | |
297 } | |
298 if (!ParseGlyphClassDefTable(file, data + offset_glyph_class_def, | |
299 length - offset_glyph_class_def, | |
300 num_glyphs)) { | |
301 DROP_THIS_TABLE("Invalid glyph classes"); | |
302 return true; | |
303 } | |
304 gdef->has_glyph_class_def = true; | |
305 } | |
306 | |
307 if (offset_attach_list) { | |
308 if (offset_attach_list >= length || | |
309 offset_attach_list < gdef_header_end) { | |
310 DROP_THIS_TABLE("Invalid offset to attachment list"); | |
311 return true; | |
312 } | |
313 if (!ParseAttachListTable(file, data + offset_attach_list, | |
314 length - offset_attach_list, | |
315 num_glyphs)) { | |
316 DROP_THIS_TABLE("Invalid attachment list"); | |
317 return true; | |
318 } | |
319 } | |
320 | |
321 if (offset_lig_caret_list) { | |
322 if (offset_lig_caret_list >= length || | |
323 offset_lig_caret_list < gdef_header_end) { | |
324 DROP_THIS_TABLE("Invalid offset to ligature caret list"); | |
325 return true; | |
326 } | |
327 if (!ParseLigCaretListTable(file, data + offset_lig_caret_list, | |
328 length - offset_lig_caret_list, | |
329 num_glyphs)) { | |
330 DROP_THIS_TABLE("Invalid ligature caret list"); | |
331 return true; | |
332 } | |
333 } | |
334 | |
335 if (offset_mark_attach_class_def) { | |
336 if (offset_mark_attach_class_def >= length || | |
337 offset_mark_attach_class_def < gdef_header_end) { | |
338 return OTS_FAILURE_MSG("Invalid offset to mark attachment list"); | |
339 } | |
340 if (!ParseMarkAttachClassDefTable(file, | |
341 data + offset_mark_attach_class_def, | |
342 length - offset_mark_attach_class_def, | |
343 num_glyphs)) { | |
344 DROP_THIS_TABLE("Invalid mark attachment list"); | |
345 return true; | |
346 } | |
347 gdef->has_mark_attachment_class_def = true; | |
348 } | |
349 | |
350 if (offset_mark_glyph_sets_def) { | |
351 if (offset_mark_glyph_sets_def >= length || | |
352 offset_mark_glyph_sets_def < gdef_header_end) { | |
353 return OTS_FAILURE_MSG("invalid offset to mark glyph sets"); | |
354 } | |
355 if (!ParseMarkGlyphSetsDefTable(file, | |
356 data + offset_mark_glyph_sets_def, | |
357 length - offset_mark_glyph_sets_def, | |
358 num_glyphs)) { | |
359 DROP_THIS_TABLE("Invalid mark glyph sets"); | |
360 return true; | |
361 } | |
362 gdef->has_mark_glyph_sets_def = true; | |
363 } | |
364 gdef->data = data; | |
365 gdef->length = length; | |
366 return true; | |
367 } | |
368 | |
369 bool ots_gdef_should_serialise(OpenTypeFile *file) { | |
370 return file->gdef != NULL && file->gdef->data != NULL; | |
371 } | |
372 | |
373 bool ots_gdef_serialise(OTSStream *out, OpenTypeFile *file) { | |
374 if (!out->Write(file->gdef->data, file->gdef->length)) { | |
375 return OTS_FAILURE_MSG("Failed to write GDEF table"); | |
376 } | |
377 | |
378 return true; | |
379 } | |
380 | |
381 void ots_gdef_free(OpenTypeFile *file) { | |
382 delete file->gdef; | |
383 } | |
384 | |
385 } // namespace ots | |
386 | |
387 #undef TABLE_NAME | |
388 #undef DROP_THIS_TABLE | |
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