bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 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 "layout.h" |
| 6 | |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 7 | #include <limits> |
| 8 | #include <vector> |
| 9 | |
| 10 | #include "gdef.h" |
| 11 | |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 12 | // OpenType Layout Common Table Formats |
| 13 | // http://www.microsoft.com/typography/otspec/chapter2.htm |
| 14 | |
| 15 | namespace { |
| 16 | |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 17 | // The 'DFLT' tag of script table. |
| 18 | const uint32_t kScriptTableTagDflt = 0x44464c54; |
| 19 | // The value which represents there is no required feature index. |
| 20 | const uint16_t kNoRequiredFeatureIndexDefined = 0xFFFF; |
| 21 | // The lookup flag bit which indicates existence of MarkFilteringSet. |
| 22 | const uint16_t kUseMarkFilteringSetBit = 0x0010; |
| 23 | // The mask for MarkAttachmentType. |
| 24 | const uint16_t kMarkAttachmentTypeMask = 0xFF00; |
| 25 | // The maximum type number of format for device tables. |
| 26 | const uint16_t kMaxDeltaFormatType = 3; |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 27 | // The maximum number of class value. |
| 28 | const uint16_t kMaxClassDefValue = 0xFFFF; |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 29 | |
| 30 | struct ScriptRecord { |
| 31 | uint32_t tag; |
| 32 | uint16_t offset; |
| 33 | }; |
| 34 | |
| 35 | struct LangSysRecord { |
| 36 | uint32_t tag; |
| 37 | uint16_t offset; |
| 38 | }; |
| 39 | |
| 40 | struct FeatureRecord { |
| 41 | uint32_t tag; |
| 42 | uint16_t offset; |
| 43 | }; |
| 44 | |
| 45 | bool ParseLangSysTable(ots::Buffer *subtable, const uint32_t tag, |
| 46 | const uint16_t num_features) { |
| 47 | uint16_t offset_lookup_order = 0; |
| 48 | uint16_t req_feature_index = 0; |
| 49 | uint16_t feature_count = 0; |
| 50 | if (!subtable->ReadU16(&offset_lookup_order) || |
| 51 | !subtable->ReadU16(&req_feature_index) || |
| 52 | !subtable->ReadU16(&feature_count)) { |
| 53 | return OTS_FAILURE(); |
| 54 | } |
| 55 | // |offset_lookup_order| is reserved and should be NULL. |
| 56 | if (offset_lookup_order != 0) { |
| 57 | return OTS_FAILURE(); |
| 58 | } |
| 59 | if (req_feature_index != kNoRequiredFeatureIndexDefined && |
| 60 | req_feature_index >= num_features) { |
| 61 | return OTS_FAILURE(); |
| 62 | } |
| 63 | if (feature_count > num_features) { |
| 64 | return OTS_FAILURE(); |
| 65 | } |
| 66 | |
| 67 | for (unsigned i = 0; i < feature_count; ++i) { |
| 68 | uint16_t feature_index = 0; |
| 69 | if (!subtable->ReadU16(&feature_index)) { |
| 70 | return OTS_FAILURE(); |
| 71 | } |
| 72 | if (feature_index >= num_features) { |
| 73 | return OTS_FAILURE(); |
| 74 | } |
| 75 | } |
| 76 | return true; |
| 77 | } |
| 78 | |
| 79 | bool ParseScriptTable(const uint8_t *data, const size_t length, |
| 80 | const uint32_t tag, const uint16_t num_features) { |
| 81 | ots::Buffer subtable(data, length); |
| 82 | |
| 83 | uint16_t offset_default_lang_sys = 0; |
| 84 | uint16_t lang_sys_count = 0; |
| 85 | if (!subtable.ReadU16(&offset_default_lang_sys) || |
| 86 | !subtable.ReadU16(&lang_sys_count)) { |
| 87 | return OTS_FAILURE(); |
| 88 | } |
| 89 | |
| 90 | // The spec requires a script table for 'DFLT' tag must contain non-NULL |
| 91 | // |offset_default_lang_sys| and |lang_sys_count| == 0 |
| 92 | if (tag == kScriptTableTagDflt && |
| 93 | (offset_default_lang_sys == 0 || lang_sys_count != 0)) { |
| 94 | OTS_WARNING("DFLT table doesn't satisfy the spec."); |
| 95 | return OTS_FAILURE(); |
| 96 | } |
| 97 | |
| 98 | const unsigned lang_sys_record_end = static_cast<unsigned>(4) + |
| 99 | lang_sys_count * 6; |
| 100 | if (lang_sys_record_end > std::numeric_limits<uint16_t>::max()) { |
| 101 | return OTS_FAILURE(); |
| 102 | } |
| 103 | |
| 104 | std::vector<LangSysRecord> lang_sys_records; |
| 105 | lang_sys_records.resize(lang_sys_count); |
| 106 | uint32_t last_tag = 0; |
| 107 | for (unsigned i = 0; i < lang_sys_count; ++i) { |
| 108 | if (!subtable.ReadU32(&lang_sys_records[i].tag) || |
| 109 | !subtable.ReadU16(&lang_sys_records[i].offset)) { |
| 110 | return OTS_FAILURE(); |
| 111 | } |
| 112 | // The record array must store the records alphabetically by tag |
| 113 | if (last_tag != 0 && last_tag > lang_sys_records[i].tag) { |
| 114 | return OTS_FAILURE(); |
| 115 | } |
| 116 | if (lang_sys_records[i].offset < lang_sys_record_end || |
| 117 | lang_sys_records[i].offset >= length) { |
| 118 | return OTS_FAILURE(); |
| 119 | } |
| 120 | last_tag = lang_sys_records[i].tag; |
| 121 | } |
| 122 | |
| 123 | // Check lang sys tables |
| 124 | for (unsigned i = 0; i < lang_sys_count; ++i) { |
| 125 | subtable.set_offset(lang_sys_records[i].offset); |
| 126 | if (!ParseLangSysTable(&subtable, lang_sys_records[i].tag, num_features)) { |
| 127 | return OTS_FAILURE(); |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | return true; |
| 132 | } |
| 133 | |
| 134 | bool ParseFeatureTable(const uint8_t *data, const size_t length, |
| 135 | const uint16_t num_lookups) { |
| 136 | ots::Buffer subtable(data, length); |
| 137 | |
| 138 | uint16_t offset_feature_params = 0; |
| 139 | uint16_t lookup_count = 0; |
| 140 | if (!subtable.ReadU16(&offset_feature_params) || |
| 141 | !subtable.ReadU16(&lookup_count)) { |
| 142 | return OTS_FAILURE(); |
| 143 | } |
| 144 | |
| 145 | const unsigned feature_table_end = static_cast<unsigned>(4) + |
| 146 | num_lookups * 2; |
| 147 | if (feature_table_end > std::numeric_limits<uint16_t>::max()) { |
| 148 | return OTS_FAILURE(); |
| 149 | } |
| 150 | // |offset_feature_params| is generally set to NULL. |
| 151 | if (offset_feature_params != 0 && |
| 152 | (offset_feature_params < feature_table_end || |
| 153 | offset_feature_params >= length)) { |
| 154 | return OTS_FAILURE(); |
| 155 | } |
| 156 | |
| 157 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 158 | uint16_t lookup_index = 0; |
| 159 | if (!subtable.ReadU16(&lookup_index)) { |
| 160 | return OTS_FAILURE(); |
| 161 | } |
| 162 | // lookup index starts with 0. |
| 163 | if (lookup_index >= num_lookups) { |
| 164 | return OTS_FAILURE(); |
| 165 | } |
| 166 | } |
| 167 | return true; |
| 168 | } |
| 169 | |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 170 | bool ParseLookupTable(ots::OpenTypeFile *file, const uint8_t *data, |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 171 | const size_t length, |
| 172 | const ots::LookupSubtableParser* parser) { |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 173 | ots::Buffer subtable(data, length); |
| 174 | |
| 175 | uint16_t lookup_type = 0; |
| 176 | uint16_t lookup_flag = 0; |
| 177 | uint16_t subtable_count = 0; |
| 178 | if (!subtable.ReadU16(&lookup_type) || |
| 179 | !subtable.ReadU16(&lookup_flag) || |
| 180 | !subtable.ReadU16(&subtable_count)) { |
| 181 | return OTS_FAILURE(); |
| 182 | } |
| 183 | |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 184 | if (lookup_type == 0 || lookup_type > parser->num_types) { |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 185 | return OTS_FAILURE(); |
| 186 | } |
| 187 | |
| 188 | // Check lookup flags. |
| 189 | if ((lookup_flag & kMarkAttachmentTypeMask) && |
| 190 | (!file->gdef || !file->gdef->has_mark_attachment_class_def)) { |
| 191 | return OTS_FAILURE(); |
| 192 | } |
| 193 | bool use_mark_filtering_set = false; |
| 194 | if (lookup_flag & kUseMarkFilteringSetBit) { |
| 195 | if (!file->gdef || !file->gdef->has_mark_glyph_sets_def) { |
| 196 | return OTS_FAILURE(); |
| 197 | } |
| 198 | use_mark_filtering_set = true; |
| 199 | } |
| 200 | |
| 201 | std::vector<uint16_t> subtables; |
| 202 | subtables.reserve(subtable_count); |
| 203 | // If the |kUseMarkFilteringSetBit| of |lookup_flag| is set, |
| 204 | // extra 2 bytes will follow after subtable offset array. |
| 205 | const unsigned lookup_table_end = |
| 206 | static_cast<unsigned>(use_mark_filtering_set ? 8 : 6) + |
| 207 | subtable_count * 2; |
| 208 | if (lookup_table_end > std::numeric_limits<uint16_t>::max()) { |
| 209 | return OTS_FAILURE(); |
| 210 | } |
| 211 | for (unsigned i = 0; i < subtable_count; ++i) { |
| 212 | if (!subtable.ReadU16(&subtables[i])) { |
| 213 | return OTS_FAILURE(); |
| 214 | } |
| 215 | if (subtables[i] < lookup_table_end || subtables[i] >= length) { |
| 216 | return OTS_FAILURE(); |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | if (use_mark_filtering_set) { |
| 221 | uint16_t mark_filtering_set = 0; |
| 222 | if (!subtable.ReadU16(&mark_filtering_set)) { |
| 223 | return OTS_FAILURE(); |
| 224 | } |
| 225 | if (file->gdef->num_mark_glyph_sets == 0 || |
| 226 | mark_filtering_set >= file->gdef->num_mark_glyph_sets) { |
| 227 | return OTS_FAILURE(); |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | // Parse lookup subtables for this lookup type. |
| 232 | for (unsigned i = 0; i < subtable_count; ++i) { |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 233 | if (!parser->Parse(file, data + subtables[i], length - subtables[i], |
| 234 | lookup_type)) { |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 235 | return OTS_FAILURE(); |
| 236 | } |
| 237 | } |
| 238 | return true; |
| 239 | } |
| 240 | |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 241 | bool ParseClassDefFormat1(const uint8_t *data, size_t length, |
| 242 | const uint16_t num_glyphs, |
| 243 | const uint16_t num_classes) { |
| 244 | ots::Buffer subtable(data, length); |
| 245 | |
| 246 | // Skip format field. |
| 247 | if (!subtable.Skip(2)) { |
| 248 | return OTS_FAILURE(); |
| 249 | } |
| 250 | |
| 251 | uint16_t start_glyph = 0; |
| 252 | if (!subtable.ReadU16(&start_glyph)) { |
| 253 | return OTS_FAILURE(); |
| 254 | } |
| 255 | if (start_glyph > num_glyphs) { |
| 256 | OTS_WARNING("bad start glyph ID: %u", start_glyph); |
| 257 | return OTS_FAILURE(); |
| 258 | } |
| 259 | |
| 260 | uint16_t glyph_count = 0; |
| 261 | if (!subtable.ReadU16(&glyph_count)) { |
| 262 | return OTS_FAILURE(); |
| 263 | } |
| 264 | if (glyph_count > num_glyphs) { |
| 265 | OTS_WARNING("bad glyph count: %u", glyph_count); |
| 266 | return OTS_FAILURE(); |
| 267 | } |
| 268 | for (unsigned i = 0; i < glyph_count; ++i) { |
| 269 | uint16_t class_value = 0; |
| 270 | if (!subtable.ReadU16(&class_value)) { |
| 271 | return OTS_FAILURE(); |
| 272 | } |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 273 | if (class_value > num_classes) { |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 274 | OTS_WARNING("bad class value: %u", class_value); |
| 275 | return OTS_FAILURE(); |
| 276 | } |
| 277 | } |
| 278 | |
| 279 | return true; |
| 280 | } |
| 281 | |
| 282 | bool ParseClassDefFormat2(const uint8_t *data, size_t length, |
| 283 | const uint16_t num_glyphs, |
| 284 | const uint16_t num_classes) { |
| 285 | ots::Buffer subtable(data, length); |
| 286 | |
| 287 | // Skip format field. |
| 288 | if (!subtable.Skip(2)) { |
| 289 | return OTS_FAILURE(); |
| 290 | } |
| 291 | |
| 292 | uint16_t range_count = 0; |
| 293 | if (!subtable.ReadU16(&range_count)) { |
| 294 | return OTS_FAILURE(); |
| 295 | } |
| 296 | if (range_count > num_glyphs) { |
| 297 | OTS_WARNING("bad range count: %u", range_count); |
| 298 | return OTS_FAILURE(); |
| 299 | } |
| 300 | |
| 301 | uint16_t last_end = 0; |
| 302 | for (unsigned i = 0; i < range_count; ++i) { |
| 303 | uint16_t start = 0; |
| 304 | uint16_t end = 0; |
| 305 | uint16_t class_value = 0; |
| 306 | if (!subtable.ReadU16(&start) || |
| 307 | !subtable.ReadU16(&end) || |
| 308 | !subtable.ReadU16(&class_value)) { |
| 309 | return OTS_FAILURE(); |
| 310 | } |
| 311 | if (start > end || (last_end && start <= last_end)) { |
| 312 | OTS_WARNING("glyph range is overlapping."); |
| 313 | return OTS_FAILURE(); |
| 314 | } |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 315 | if (class_value > num_classes) { |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 316 | OTS_WARNING("bad class value: %u", class_value); |
| 317 | return OTS_FAILURE(); |
| 318 | } |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 319 | last_end = end; |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 320 | } |
| 321 | |
| 322 | return true; |
| 323 | } |
| 324 | |
| 325 | bool ParseCoverageFormat1(const uint8_t *data, size_t length, |
| 326 | const uint16_t num_glyphs) { |
| 327 | ots::Buffer subtable(data, length); |
| 328 | |
| 329 | // Skip format field. |
| 330 | if (!subtable.Skip(2)) { |
| 331 | return OTS_FAILURE(); |
| 332 | } |
| 333 | |
| 334 | uint16_t glyph_count = 0; |
| 335 | if (!subtable.ReadU16(&glyph_count)) { |
| 336 | return OTS_FAILURE(); |
| 337 | } |
| 338 | if (glyph_count > num_glyphs) { |
| 339 | OTS_WARNING("bad glyph count: %u", glyph_count); |
| 340 | return OTS_FAILURE(); |
| 341 | } |
| 342 | for (unsigned i = 0; i < glyph_count; ++i) { |
| 343 | uint16_t glyph = 0; |
| 344 | if (!subtable.ReadU16(&glyph)) { |
| 345 | return OTS_FAILURE(); |
| 346 | } |
| 347 | if (glyph > num_glyphs) { |
| 348 | OTS_WARNING("bad glyph ID: %u", glyph); |
| 349 | return OTS_FAILURE(); |
| 350 | } |
| 351 | } |
| 352 | |
| 353 | return true; |
| 354 | } |
| 355 | |
| 356 | bool ParseCoverageFormat2(const uint8_t *data, size_t length, |
| 357 | const uint16_t num_glyphs) { |
| 358 | ots::Buffer subtable(data, length); |
| 359 | |
| 360 | // Skip format field. |
| 361 | if (!subtable.Skip(2)) { |
| 362 | return OTS_FAILURE(); |
| 363 | } |
| 364 | |
| 365 | uint16_t range_count = 0; |
| 366 | if (!subtable.ReadU16(&range_count)) { |
| 367 | return OTS_FAILURE(); |
| 368 | } |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 369 | if (range_count > num_glyphs) { |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 370 | OTS_WARNING("bad range count: %u", range_count); |
| 371 | return OTS_FAILURE(); |
| 372 | } |
| 373 | uint16_t last_end = 0; |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 374 | uint16_t last_start_coverage_index = 0; |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 375 | for (unsigned i = 0; i < range_count; ++i) { |
| 376 | uint16_t start = 0; |
| 377 | uint16_t end = 0; |
| 378 | uint16_t start_coverage_index = 0; |
| 379 | if (!subtable.ReadU16(&start) || |
| 380 | !subtable.ReadU16(&end) || |
| 381 | !subtable.ReadU16(&start_coverage_index)) { |
| 382 | return OTS_FAILURE(); |
| 383 | } |
| 384 | if (start > end || (last_end && start <= last_end)) { |
| 385 | OTS_WARNING("glyph range is overlapping."); |
| 386 | return OTS_FAILURE(); |
| 387 | } |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 388 | if (start_coverage_index != last_start_coverage_index) { |
| 389 | OTS_WARNING("bad start coverage index."); |
| 390 | return OTS_FAILURE(); |
| 391 | } |
| 392 | last_end = end; |
| 393 | last_start_coverage_index += end - start + 1; |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 394 | } |
| 395 | |
| 396 | return true; |
| 397 | } |
| 398 | |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 399 | // Parsers for Contextual subtables in GSUB/GPOS tables. |
| 400 | |
| 401 | bool ParseLookupRecord(ots::Buffer *subtable, const uint16_t num_glyphs, |
| 402 | const uint16_t num_lookups) { |
| 403 | uint16_t sequence_index = 0; |
| 404 | uint16_t lookup_list_index = 0; |
| 405 | if (!subtable->ReadU16(&sequence_index) || |
| 406 | !subtable->ReadU16(&lookup_list_index)) { |
| 407 | return OTS_FAILURE(); |
| 408 | } |
| 409 | if (sequence_index >= num_glyphs) { |
| 410 | return OTS_FAILURE(); |
| 411 | } |
| 412 | if (lookup_list_index >= num_lookups) { |
| 413 | return OTS_FAILURE(); |
| 414 | } |
| 415 | return true; |
| 416 | } |
| 417 | |
| 418 | bool ParseRuleSubtable(const uint8_t *data, const size_t length, |
| 419 | const uint16_t num_glyphs, |
| 420 | const uint16_t num_lookups) { |
| 421 | ots::Buffer subtable(data, length); |
| 422 | |
| 423 | uint16_t glyph_count = 0; |
| 424 | uint16_t lookup_count = 0; |
| 425 | if (!subtable.ReadU16(&glyph_count) || |
| 426 | !subtable.ReadU16(&lookup_count)) { |
| 427 | return OTS_FAILURE(); |
| 428 | } |
| 429 | |
| 430 | if (glyph_count == 0 || glyph_count >= num_glyphs) { |
| 431 | return OTS_FAILURE(); |
| 432 | } |
| 433 | for (unsigned i = 0; i < glyph_count - static_cast<unsigned>(1); ++i) { |
| 434 | uint16_t glyph_id = 0; |
| 435 | if (!subtable.ReadU16(&glyph_id)) { |
| 436 | return OTS_FAILURE(); |
| 437 | } |
| 438 | if (glyph_id > num_glyphs) { |
| 439 | return OTS_FAILURE(); |
| 440 | } |
| 441 | } |
| 442 | |
| 443 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 444 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 445 | return OTS_FAILURE(); |
| 446 | } |
| 447 | } |
| 448 | return true; |
| 449 | } |
| 450 | |
| 451 | bool ParseRuleSetTable(const uint8_t *data, const size_t length, |
| 452 | const uint16_t num_glyphs, |
| 453 | const uint16_t num_lookups) { |
| 454 | ots::Buffer subtable(data, length); |
| 455 | |
| 456 | uint16_t rule_count = 0; |
| 457 | if (!subtable.ReadU16(&rule_count)) { |
| 458 | return OTS_FAILURE(); |
| 459 | } |
| 460 | const unsigned rule_end = static_cast<unsigned>(2) + |
| 461 | rule_count * 2; |
| 462 | if (rule_end > std::numeric_limits<uint16_t>::max()) { |
| 463 | return OTS_FAILURE(); |
| 464 | } |
| 465 | |
| 466 | for (unsigned i = 0; i < rule_count; ++i) { |
| 467 | uint16_t offset_rule = 0; |
| 468 | if (!subtable.ReadU16(&offset_rule)) { |
| 469 | return OTS_FAILURE(); |
| 470 | } |
| 471 | if (offset_rule < rule_end || offset_rule >= length) { |
| 472 | return OTS_FAILURE(); |
| 473 | } |
| 474 | if (!ParseRuleSubtable(data + offset_rule, length - offset_rule, |
| 475 | num_glyphs, num_lookups)) { |
| 476 | return OTS_FAILURE(); |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | return true; |
| 481 | } |
| 482 | |
| 483 | bool ParseContextFormat1(const uint8_t *data, const size_t length, |
| 484 | const uint16_t num_glyphs, |
| 485 | const uint16_t num_lookups) { |
| 486 | ots::Buffer subtable(data, length); |
| 487 | |
| 488 | uint16_t offset_coverage = 0; |
| 489 | uint16_t rule_set_count = 0; |
| 490 | // Skip format field. |
| 491 | if (!subtable.Skip(2) || |
| 492 | !subtable.ReadU16(&offset_coverage) || |
| 493 | !subtable.ReadU16(&rule_set_count)) { |
| 494 | return OTS_FAILURE(); |
| 495 | } |
| 496 | |
| 497 | const unsigned rule_set_end = static_cast<unsigned>(6) + |
| 498 | rule_set_count * 2; |
| 499 | if (rule_set_end > std::numeric_limits<uint16_t>::max()) { |
| 500 | return OTS_FAILURE(); |
| 501 | } |
| 502 | if (offset_coverage < rule_set_end || offset_coverage >= length) { |
| 503 | return OTS_FAILURE(); |
| 504 | } |
| 505 | if (!ots::ParseCoverageTable(data + offset_coverage, |
| 506 | length - offset_coverage, num_glyphs)) { |
| 507 | return OTS_FAILURE(); |
| 508 | } |
| 509 | |
| 510 | for (unsigned i = 0; i < rule_set_count; ++i) { |
| 511 | uint16_t offset_rule = 0; |
| 512 | if (!subtable.ReadU16(&offset_rule)) { |
| 513 | return OTS_FAILURE(); |
| 514 | } |
| 515 | if (offset_rule < rule_set_end || offset_rule >= length) { |
| 516 | return OTS_FAILURE(); |
| 517 | } |
| 518 | if (!ParseRuleSetTable(data + offset_rule, length - offset_rule, |
| 519 | num_glyphs, num_lookups)) { |
| 520 | return OTS_FAILURE(); |
| 521 | } |
| 522 | } |
| 523 | |
| 524 | return true; |
| 525 | } |
| 526 | |
| 527 | bool ParseClassRuleTable(const uint8_t *data, const size_t length, |
| 528 | const uint16_t num_glyphs, |
| 529 | const uint16_t num_lookups) { |
| 530 | ots::Buffer subtable(data, length); |
| 531 | |
| 532 | uint16_t glyph_count = 0; |
| 533 | uint16_t lookup_count = 0; |
| 534 | if (!subtable.ReadU16(&glyph_count) || |
| 535 | !subtable.ReadU16(&lookup_count)) { |
| 536 | return OTS_FAILURE(); |
| 537 | } |
| 538 | |
| 539 | if (glyph_count == 0 || glyph_count >= num_glyphs) { |
| 540 | return OTS_FAILURE(); |
| 541 | } |
| 542 | |
| 543 | // ClassRule table contains an array of classes. Each value of classes |
| 544 | // could take arbitrary values including zero so we don't check these value. |
| 545 | const unsigned num_classes = glyph_count - static_cast<unsigned>(1); |
| 546 | if (!subtable.Skip(2 * num_classes)) { |
| 547 | return OTS_FAILURE(); |
| 548 | } |
| 549 | |
| 550 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 551 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 552 | return OTS_FAILURE(); |
| 553 | } |
| 554 | } |
| 555 | return true; |
| 556 | } |
| 557 | |
| 558 | bool ParseClassSetTable(const uint8_t *data, const size_t length, |
| 559 | const uint16_t num_glyphs, |
| 560 | const uint16_t num_lookups) { |
| 561 | ots::Buffer subtable(data, length); |
| 562 | |
| 563 | uint16_t class_rule_count = 0; |
| 564 | if (!subtable.ReadU16(&class_rule_count)) { |
| 565 | return OTS_FAILURE(); |
| 566 | } |
| 567 | const unsigned class_rule_end = static_cast<unsigned>(2) + |
| 568 | class_rule_count * 2; |
| 569 | if (class_rule_end > std::numeric_limits<uint16_t>::max()) { |
| 570 | return OTS_FAILURE(); |
| 571 | } |
| 572 | for (unsigned i = 0; i < class_rule_count; ++i) { |
| 573 | uint16_t offset_class_rule = 0; |
| 574 | if (!subtable.ReadU16(&offset_class_rule)) { |
| 575 | return OTS_FAILURE(); |
| 576 | } |
| 577 | if (offset_class_rule < class_rule_end || offset_class_rule >= length) { |
| 578 | return OTS_FAILURE(); |
| 579 | } |
| 580 | if (!ParseClassRuleTable(data + offset_class_rule, |
| 581 | length - offset_class_rule, num_glyphs, |
| 582 | num_lookups)) { |
| 583 | return OTS_FAILURE(); |
| 584 | } |
| 585 | } |
| 586 | |
| 587 | return true; |
| 588 | } |
| 589 | |
| 590 | bool ParseContextFormat2(const uint8_t *data, const size_t length, |
| 591 | const uint16_t num_glyphs, |
| 592 | const uint16_t num_lookups) { |
| 593 | ots::Buffer subtable(data, length); |
| 594 | |
| 595 | uint16_t offset_coverage = 0; |
| 596 | uint16_t offset_class_def = 0; |
| 597 | uint16_t class_set_cnt = 0; |
| 598 | // Skip format field. |
| 599 | if (!subtable.Skip(2) || |
| 600 | !subtable.ReadU16(&offset_coverage) || |
| 601 | !subtable.ReadU16(&offset_class_def) || |
| 602 | !subtable.ReadU16(&class_set_cnt)) { |
| 603 | return OTS_FAILURE(); |
| 604 | } |
| 605 | |
| 606 | const unsigned class_set_end = static_cast<unsigned>(8) + |
| 607 | class_set_cnt * 2; |
| 608 | if (class_set_end > std::numeric_limits<uint16_t>::max()) { |
| 609 | return OTS_FAILURE(); |
| 610 | } |
| 611 | if (offset_coverage < class_set_end || offset_coverage >= length) { |
| 612 | return OTS_FAILURE(); |
| 613 | } |
| 614 | if (!ots::ParseCoverageTable(data + offset_coverage, |
| 615 | length - offset_coverage, num_glyphs)) { |
| 616 | return OTS_FAILURE(); |
| 617 | } |
| 618 | |
| 619 | if (offset_class_def < class_set_end || offset_class_def >= length) { |
| 620 | return OTS_FAILURE(); |
| 621 | } |
| 622 | if (!ots::ParseClassDefTable(data + offset_class_def, |
| 623 | length - offset_class_def, |
| 624 | num_glyphs, kMaxClassDefValue)) { |
| 625 | return OTS_FAILURE(); |
| 626 | } |
| 627 | |
| 628 | for (unsigned i = 0; i < class_set_cnt; ++i) { |
| 629 | uint16_t offset_class_rule = 0; |
| 630 | if (!subtable.ReadU16(&offset_class_rule)) { |
| 631 | return OTS_FAILURE(); |
| 632 | } |
| 633 | if (offset_class_rule) { |
| 634 | if (offset_class_rule < class_set_end || offset_class_rule >= length) { |
| 635 | return OTS_FAILURE(); |
| 636 | } |
| 637 | if (!ParseClassSetTable(data + offset_class_rule, |
| 638 | length - offset_class_rule, num_glyphs, |
| 639 | num_lookups)) { |
| 640 | return OTS_FAILURE(); |
| 641 | } |
| 642 | } |
| 643 | } |
| 644 | |
| 645 | return true; |
| 646 | } |
| 647 | |
| 648 | bool ParseContextFormat3(const uint8_t *data, const size_t length, |
| 649 | const uint16_t num_glyphs, |
| 650 | const uint16_t num_lookups) { |
| 651 | ots::Buffer subtable(data, length); |
| 652 | |
| 653 | uint16_t glyph_count = 0; |
| 654 | uint16_t lookup_count = 0; |
| 655 | // Skip format field. |
| 656 | if (!subtable.Skip(2) || |
| 657 | !subtable.ReadU16(&glyph_count) || |
| 658 | !subtable.ReadU16(&lookup_count)) { |
| 659 | return OTS_FAILURE(); |
| 660 | } |
| 661 | |
| 662 | if (glyph_count >= num_glyphs) { |
| 663 | return OTS_FAILURE(); |
| 664 | } |
| 665 | const unsigned lookup_record_end = static_cast<unsigned>(6) + |
| 666 | glyph_count * 2 + lookup_count * 4; |
| 667 | if (lookup_record_end > std::numeric_limits<uint16_t>::max()) { |
| 668 | return OTS_FAILURE(); |
| 669 | } |
| 670 | for (unsigned i = 0; i < glyph_count; ++i) { |
| 671 | uint16_t offset_coverage = 0; |
| 672 | if (!subtable.ReadU16(&offset_coverage)) { |
| 673 | return OTS_FAILURE(); |
| 674 | } |
| 675 | if (offset_coverage < lookup_record_end || offset_coverage >= length) { |
| 676 | return OTS_FAILURE(); |
| 677 | } |
| 678 | if (!ots::ParseCoverageTable(data + offset_coverage, |
| 679 | length - offset_coverage, num_glyphs)) { |
| 680 | return OTS_FAILURE(); |
| 681 | } |
| 682 | } |
| 683 | |
| 684 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 685 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 686 | return OTS_FAILURE(); |
| 687 | } |
| 688 | } |
| 689 | |
| 690 | return true; |
| 691 | } |
| 692 | |
| 693 | // Parsers for Chaning Contextual subtables in GSUB/GPOS tables. |
| 694 | |
| 695 | bool ParseChainRuleSubtable(const uint8_t *data, const size_t length, |
| 696 | const uint16_t num_glyphs, |
| 697 | const uint16_t num_lookups) { |
| 698 | ots::Buffer subtable(data, length); |
| 699 | |
| 700 | uint16_t backtrack_count = 0; |
| 701 | if (!subtable.ReadU16(&backtrack_count)) { |
| 702 | return OTS_FAILURE(); |
| 703 | } |
| 704 | if (backtrack_count >= num_glyphs) { |
| 705 | return OTS_FAILURE(); |
| 706 | } |
| 707 | for (unsigned i = 0; i < backtrack_count; ++i) { |
| 708 | uint16_t glyph_id = 0; |
| 709 | if (!subtable.ReadU16(&glyph_id)) { |
| 710 | return OTS_FAILURE(); |
| 711 | } |
| 712 | if (glyph_id > num_glyphs) { |
| 713 | return OTS_FAILURE(); |
| 714 | } |
| 715 | } |
| 716 | |
| 717 | uint16_t input_count = 0; |
| 718 | if (!subtable.ReadU16(&input_count)) { |
| 719 | return OTS_FAILURE(); |
| 720 | } |
| 721 | if (input_count == 0 || input_count >= num_glyphs) { |
| 722 | return OTS_FAILURE(); |
| 723 | } |
| 724 | for (unsigned i = 0; i < input_count - static_cast<unsigned>(1); ++i) { |
| 725 | uint16_t glyph_id = 0; |
| 726 | if (!subtable.ReadU16(&glyph_id)) { |
| 727 | return OTS_FAILURE(); |
| 728 | } |
| 729 | if (glyph_id > num_glyphs) { |
| 730 | return OTS_FAILURE(); |
| 731 | } |
| 732 | } |
| 733 | |
| 734 | uint16_t lookahead_count = 0; |
| 735 | if (!subtable.ReadU16(&lookahead_count)) { |
| 736 | return OTS_FAILURE(); |
| 737 | } |
| 738 | if (lookahead_count >= num_glyphs) { |
| 739 | return OTS_FAILURE(); |
| 740 | } |
| 741 | for (unsigned i = 0; i < lookahead_count; ++i) { |
| 742 | uint16_t glyph_id = 0; |
| 743 | if (!subtable.ReadU16(&glyph_id)) { |
| 744 | return OTS_FAILURE(); |
| 745 | } |
| 746 | if (glyph_id > num_glyphs) { |
| 747 | return OTS_FAILURE(); |
| 748 | } |
| 749 | } |
| 750 | |
| 751 | uint16_t lookup_count = 0; |
| 752 | if (!subtable.ReadU16(&lookup_count)) { |
| 753 | return OTS_FAILURE(); |
| 754 | } |
| 755 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 756 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 757 | return OTS_FAILURE(); |
| 758 | } |
| 759 | } |
| 760 | |
| 761 | return true; |
| 762 | } |
| 763 | |
| 764 | bool ParseChainRuleSetTable(const uint8_t *data, const size_t length, |
| 765 | const uint16_t num_glyphs, |
| 766 | const uint16_t num_lookups) { |
| 767 | ots::Buffer subtable(data, length); |
| 768 | |
| 769 | uint16_t chain_rule_count = 0; |
| 770 | if (!subtable.ReadU16(&chain_rule_count)) { |
| 771 | return OTS_FAILURE(); |
| 772 | } |
| 773 | const unsigned chain_rule_end = static_cast<unsigned>(2) + |
| 774 | chain_rule_count * 2; |
| 775 | if (chain_rule_end > std::numeric_limits<uint16_t>::max()) { |
| 776 | return OTS_FAILURE(); |
| 777 | } |
| 778 | for (unsigned i = 0; i < chain_rule_count; ++i) { |
| 779 | uint16_t offset_chain_rule = 0; |
| 780 | if (!subtable.ReadU16(&offset_chain_rule)) { |
| 781 | return OTS_FAILURE(); |
| 782 | } |
| 783 | if (offset_chain_rule < chain_rule_end || offset_chain_rule >= length) { |
| 784 | return OTS_FAILURE(); |
| 785 | } |
| 786 | if (!ParseChainRuleSubtable(data + offset_chain_rule, |
| 787 | length - offset_chain_rule, |
| 788 | num_glyphs, num_lookups)) { |
| 789 | return OTS_FAILURE(); |
| 790 | } |
| 791 | } |
| 792 | |
| 793 | return true; |
| 794 | } |
| 795 | |
| 796 | bool ParseChainContextFormat1(const uint8_t *data, const size_t length, |
| 797 | const uint16_t num_glyphs, |
| 798 | const uint16_t num_lookups) { |
| 799 | ots::Buffer subtable(data, length); |
| 800 | |
| 801 | uint16_t offset_coverage = 0; |
| 802 | uint16_t chain_rule_set_count = 0; |
| 803 | // Skip format field. |
| 804 | if (!subtable.Skip(2) || |
| 805 | !subtable.ReadU16(&offset_coverage) || |
| 806 | !subtable.ReadU16(&chain_rule_set_count)) { |
| 807 | return OTS_FAILURE(); |
| 808 | } |
| 809 | |
| 810 | const unsigned chain_rule_set_end = static_cast<unsigned>(6) + |
| 811 | chain_rule_set_count * 2; |
| 812 | if (chain_rule_set_end > std::numeric_limits<uint16_t>::max()) { |
| 813 | return OTS_FAILURE(); |
| 814 | } |
| 815 | if (offset_coverage < chain_rule_set_end || offset_coverage >= length) { |
| 816 | return OTS_FAILURE(); |
| 817 | } |
| 818 | if (!ots::ParseCoverageTable(data + offset_coverage, |
| 819 | length - offset_coverage, num_glyphs)) { |
| 820 | return OTS_FAILURE(); |
| 821 | } |
| 822 | |
| 823 | for (unsigned i = 0; i < chain_rule_set_count; ++i) { |
| 824 | uint16_t offset_chain_rule_set = 0; |
| 825 | if (!subtable.ReadU16(&offset_chain_rule_set)) { |
| 826 | return OTS_FAILURE(); |
| 827 | } |
| 828 | if (offset_chain_rule_set < chain_rule_set_end || |
| 829 | offset_chain_rule_set >= length) { |
| 830 | return OTS_FAILURE(); |
| 831 | } |
| 832 | if (!ParseChainRuleSetTable(data + offset_chain_rule_set, |
| 833 | length - offset_chain_rule_set, |
| 834 | num_glyphs, num_lookups)) { |
| 835 | return OTS_FAILURE(); |
| 836 | } |
| 837 | } |
| 838 | |
| 839 | return true; |
| 840 | } |
| 841 | |
| 842 | bool ParseChainClassRuleSubtable(const uint8_t *data, const size_t length, |
| 843 | const uint16_t num_glyphs, |
| 844 | const uint16_t num_lookups) { |
| 845 | ots::Buffer subtable(data, length); |
| 846 | |
| 847 | // In this subtable, we don't check the value of classes for now since |
| 848 | // these could take arbitrary values. |
| 849 | |
| 850 | uint16_t backtrack_count = 0; |
| 851 | if (!subtable.ReadU16(&backtrack_count)) { |
| 852 | return OTS_FAILURE(); |
| 853 | } |
| 854 | if (backtrack_count >= num_glyphs) { |
| 855 | return OTS_FAILURE(); |
| 856 | } |
| 857 | if (!subtable.Skip(2 * backtrack_count)) { |
| 858 | return OTS_FAILURE(); |
| 859 | } |
| 860 | |
| 861 | uint16_t input_count = 0; |
| 862 | if (!subtable.ReadU16(&input_count)) { |
| 863 | return OTS_FAILURE(); |
| 864 | } |
| 865 | if (input_count == 0 || input_count >= num_glyphs) { |
| 866 | return OTS_FAILURE(); |
| 867 | } |
| 868 | if (!subtable.Skip(2 * (input_count - 1))) { |
| 869 | return OTS_FAILURE(); |
| 870 | } |
| 871 | |
| 872 | uint16_t lookahead_count = 0; |
| 873 | if (!subtable.ReadU16(&lookahead_count)) { |
| 874 | return OTS_FAILURE(); |
| 875 | } |
| 876 | if (lookahead_count >= num_glyphs) { |
| 877 | return OTS_FAILURE(); |
| 878 | } |
| 879 | if (!subtable.Skip(2 * lookahead_count)) { |
| 880 | return OTS_FAILURE(); |
| 881 | } |
| 882 | |
| 883 | uint16_t lookup_count = 0; |
| 884 | if (!subtable.ReadU16(&lookup_count)) { |
| 885 | return OTS_FAILURE(); |
| 886 | } |
| 887 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 888 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 889 | return OTS_FAILURE(); |
| 890 | } |
| 891 | } |
| 892 | |
| 893 | return true; |
| 894 | } |
| 895 | |
| 896 | bool ParseChainClassSetTable(const uint8_t *data, const size_t length, |
| 897 | const uint16_t num_glyphs, |
| 898 | const uint16_t num_lookups) { |
| 899 | ots::Buffer subtable(data, length); |
| 900 | |
| 901 | uint16_t chain_class_rule_count = 0; |
| 902 | if (!subtable.ReadU16(&chain_class_rule_count)) { |
| 903 | return OTS_FAILURE(); |
| 904 | } |
| 905 | const unsigned chain_class_rule_end = static_cast<unsigned>(2) + |
| 906 | chain_class_rule_count * 2; |
| 907 | if (chain_class_rule_end > std::numeric_limits<uint16_t>::max()) { |
| 908 | return OTS_FAILURE(); |
| 909 | } |
| 910 | for (unsigned i = 0; i < chain_class_rule_count; ++i) { |
| 911 | uint16_t offset_chain_class_rule = 0; |
| 912 | if (!subtable.ReadU16(&offset_chain_class_rule)) { |
| 913 | return OTS_FAILURE(); |
| 914 | } |
| 915 | if (offset_chain_class_rule < chain_class_rule_end || |
| 916 | offset_chain_class_rule >= length) { |
| 917 | return OTS_FAILURE(); |
| 918 | } |
| 919 | if (!ParseChainClassRuleSubtable(data + offset_chain_class_rule, |
| 920 | length - offset_chain_class_rule, |
| 921 | num_glyphs, num_lookups)) { |
| 922 | return OTS_FAILURE(); |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | return true; |
| 927 | } |
| 928 | |
| 929 | bool ParseChainContextFormat2(const uint8_t *data, const size_t length, |
| 930 | const uint16_t num_glyphs, |
| 931 | const uint16_t num_lookups) { |
| 932 | ots::Buffer subtable(data, length); |
| 933 | |
| 934 | uint16_t offset_coverage = 0; |
| 935 | uint16_t offset_backtrack_class_def = 0; |
| 936 | uint16_t offset_input_class_def = 0; |
| 937 | uint16_t offset_lookahead_class_def = 0; |
| 938 | uint16_t chain_class_set_count = 0; |
| 939 | // Skip format field. |
| 940 | if (!subtable.Skip(2) || |
| 941 | !subtable.ReadU16(&offset_coverage) || |
| 942 | !subtable.ReadU16(&offset_backtrack_class_def) || |
| 943 | !subtable.ReadU16(&offset_input_class_def) || |
| 944 | !subtable.ReadU16(&offset_lookahead_class_def) || |
| 945 | !subtable.ReadU16(&chain_class_set_count)) { |
| 946 | return OTS_FAILURE(); |
| 947 | } |
| 948 | |
| 949 | const unsigned chain_class_set_end = static_cast<unsigned>(12) + |
| 950 | chain_class_set_count * 2; |
| 951 | if (chain_class_set_end > std::numeric_limits<uint16_t>::max()) { |
| 952 | return OTS_FAILURE(); |
| 953 | } |
| 954 | if (offset_coverage < chain_class_set_end || offset_coverage >= length) { |
| 955 | return OTS_FAILURE(); |
| 956 | } |
| 957 | if (!ots::ParseCoverageTable(data + offset_coverage, |
| 958 | length - offset_coverage, num_glyphs)) { |
| 959 | return OTS_FAILURE(); |
| 960 | } |
| 961 | |
| 962 | // Classes for backtrack/lookahead sequences might not be defined. |
| 963 | if (offset_backtrack_class_def) { |
| 964 | if (offset_backtrack_class_def < chain_class_set_end || |
| 965 | offset_backtrack_class_def >= length) { |
| 966 | return OTS_FAILURE(); |
| 967 | } |
| 968 | if (!ots::ParseClassDefTable(data + offset_backtrack_class_def, |
| 969 | length - offset_backtrack_class_def, |
| 970 | num_glyphs, kMaxClassDefValue)) { |
| 971 | return OTS_FAILURE(); |
| 972 | } |
| 973 | } |
| 974 | |
| 975 | if (offset_input_class_def < chain_class_set_end || |
| 976 | offset_input_class_def >= length) { |
| 977 | return OTS_FAILURE(); |
| 978 | } |
| 979 | if (!ots::ParseClassDefTable(data + offset_input_class_def, |
| 980 | length - offset_input_class_def, |
| 981 | num_glyphs, kMaxClassDefValue)) { |
| 982 | return OTS_FAILURE(); |
| 983 | } |
| 984 | |
| 985 | if (offset_lookahead_class_def) { |
| 986 | if (offset_lookahead_class_def < chain_class_set_end || |
| 987 | offset_lookahead_class_def >= length) { |
| 988 | return OTS_FAILURE(); |
| 989 | } |
| 990 | if (!ots::ParseClassDefTable(data + offset_lookahead_class_def, |
| 991 | length - offset_lookahead_class_def, |
| 992 | num_glyphs, kMaxClassDefValue)) { |
| 993 | return OTS_FAILURE(); |
| 994 | } |
| 995 | } |
| 996 | |
| 997 | for (unsigned i = 0; i < chain_class_set_count; ++i) { |
| 998 | uint16_t offset_chain_class_set = 0; |
| 999 | if (!subtable.ReadU16(&offset_chain_class_set)) { |
| 1000 | return OTS_FAILURE(); |
| 1001 | } |
| 1002 | // |offset_chain_class_set| could be NULL. |
| 1003 | if (offset_chain_class_set) { |
| 1004 | if (offset_chain_class_set < chain_class_set_end || |
| 1005 | offset_chain_class_set >= length) { |
| 1006 | return OTS_FAILURE(); |
| 1007 | } |
| 1008 | if (!ParseChainClassSetTable(data + offset_chain_class_set, |
| 1009 | length - offset_chain_class_set, |
| 1010 | num_glyphs, num_lookups)) { |
| 1011 | return OTS_FAILURE(); |
| 1012 | } |
| 1013 | } |
| 1014 | } |
| 1015 | |
| 1016 | return true; |
| 1017 | } |
| 1018 | |
| 1019 | bool ParseChainContextFormat3(const uint8_t *data, const size_t length, |
| 1020 | const uint16_t num_glyphs, |
| 1021 | const uint16_t num_lookups) { |
| 1022 | ots::Buffer subtable(data, length); |
| 1023 | |
| 1024 | uint16_t backtrack_count = 0; |
| 1025 | // Skip format field. |
| 1026 | if (!subtable.Skip(2) || |
| 1027 | !subtable.ReadU16(&backtrack_count)) { |
| 1028 | return OTS_FAILURE(); |
| 1029 | } |
| 1030 | |
| 1031 | if (backtrack_count >= num_glyphs) { |
| 1032 | return OTS_FAILURE(); |
| 1033 | } |
| 1034 | std::vector<uint16_t> offsets_backtrack; |
| 1035 | offsets_backtrack.reserve(backtrack_count); |
| 1036 | for (unsigned i = 0; i < backtrack_count; ++i) { |
| 1037 | if (!subtable.ReadU16(&offsets_backtrack[i])) { |
| 1038 | return OTS_FAILURE(); |
| 1039 | } |
| 1040 | } |
| 1041 | |
| 1042 | uint16_t input_count = 0; |
| 1043 | if (!subtable.ReadU16(&input_count)) { |
| 1044 | return OTS_FAILURE(); |
| 1045 | } |
| 1046 | if (input_count >= num_glyphs) { |
| 1047 | return OTS_FAILURE(); |
| 1048 | } |
| 1049 | std::vector<uint16_t> offsets_input; |
| 1050 | offsets_input.reserve(input_count); |
| 1051 | for (unsigned i = 0; i < input_count; ++i) { |
| 1052 | if (!subtable.ReadU16(&offsets_input[i])) { |
| 1053 | return OTS_FAILURE(); |
| 1054 | } |
| 1055 | } |
| 1056 | |
| 1057 | uint16_t lookahead_count = 0; |
| 1058 | if (!subtable.ReadU16(&lookahead_count)) { |
| 1059 | return OTS_FAILURE(); |
| 1060 | } |
| 1061 | if (lookahead_count >= num_glyphs) { |
| 1062 | return OTS_FAILURE(); |
| 1063 | } |
| 1064 | std::vector<uint16_t> offsets_lookahead; |
| 1065 | offsets_lookahead.reserve(lookahead_count); |
| 1066 | for (unsigned i = 0; i < lookahead_count; ++i) { |
| 1067 | if (!subtable.ReadU16(&offsets_lookahead[i])) { |
| 1068 | return OTS_FAILURE(); |
| 1069 | } |
| 1070 | } |
| 1071 | |
| 1072 | uint16_t lookup_count = 0; |
| 1073 | if (!subtable.ReadU16(&lookup_count)) { |
| 1074 | return OTS_FAILURE(); |
| 1075 | } |
| 1076 | for (unsigned i = 0; i < lookup_count; ++i) { |
| 1077 | if (!ParseLookupRecord(&subtable, num_glyphs, num_lookups)) { |
| 1078 | return OTS_FAILURE(); |
| 1079 | } |
| 1080 | } |
| 1081 | |
| 1082 | const unsigned lookup_record_end = static_cast<unsigned>(10) + |
| 1083 | (backtrack_count + input_count + lookahead_count) * 2 + lookup_count * 4; |
| 1084 | if (lookup_record_end > std::numeric_limits<uint16_t>::max()) { |
| 1085 | return OTS_FAILURE(); |
| 1086 | } |
| 1087 | for (unsigned i = 0; i < backtrack_count; ++i) { |
| 1088 | if (offsets_backtrack[i] < lookup_record_end || |
| 1089 | offsets_backtrack[i] >= length) { |
| 1090 | return OTS_FAILURE(); |
| 1091 | } |
| 1092 | if (!ots::ParseCoverageTable(data + offsets_backtrack[i], |
| 1093 | length - offsets_backtrack[i], num_glyphs)) { |
| 1094 | return OTS_FAILURE(); |
| 1095 | } |
| 1096 | } |
| 1097 | for (unsigned i = 0; i < input_count; ++i) { |
| 1098 | if (offsets_input[i] < lookup_record_end || offsets_input[i] >= length) { |
| 1099 | return OTS_FAILURE(); |
| 1100 | } |
| 1101 | if (!ots::ParseCoverageTable(data + offsets_input[i], |
| 1102 | length - offsets_input[i], num_glyphs)) { |
| 1103 | return OTS_FAILURE(); |
| 1104 | } |
| 1105 | } |
| 1106 | for (unsigned i = 0; i < lookahead_count; ++i) { |
| 1107 | if (offsets_lookahead[i] < lookup_record_end || |
| 1108 | offsets_lookahead[i] >= length) { |
| 1109 | return OTS_FAILURE(); |
| 1110 | } |
| 1111 | if (!ots::ParseCoverageTable(data + offsets_lookahead[i], |
| 1112 | length - offsets_lookahead[i], num_glyphs)) { |
| 1113 | return OTS_FAILURE(); |
| 1114 | } |
| 1115 | } |
| 1116 | |
| 1117 | return true; |
| 1118 | } |
| 1119 | |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 1120 | } // namespace |
| 1121 | |
| 1122 | namespace ots { |
| 1123 | |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 1124 | bool LookupSubtableParser::Parse(const OpenTypeFile *file, const uint8_t *data, |
| 1125 | const size_t length, |
| 1126 | const uint16_t lookup_type) const { |
| 1127 | for (unsigned i = 0; i < num_types; ++i) { |
| 1128 | if (parsers[i].type == lookup_type && parsers[i].parse) { |
| 1129 | if (!parsers[i].parse(file, data, length)) { |
| 1130 | return OTS_FAILURE(); |
| 1131 | } |
| 1132 | return true; |
| 1133 | } |
| 1134 | } |
| 1135 | return OTS_FAILURE(); |
| 1136 | } |
| 1137 | |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 1138 | // Parsing ScriptListTable requires number of features so we need to |
| 1139 | // parse FeatureListTable before calling this function. |
| 1140 | bool ParseScriptListTable(const uint8_t *data, const size_t length, |
| 1141 | const uint16_t num_features) { |
| 1142 | Buffer subtable(data, length); |
| 1143 | |
| 1144 | uint16_t script_count = 0; |
| 1145 | if (!subtable.ReadU16(&script_count)) { |
| 1146 | return OTS_FAILURE(); |
| 1147 | } |
| 1148 | |
| 1149 | const unsigned script_record_end = static_cast<unsigned>(2) + |
| 1150 | script_count * 6; |
| 1151 | if (script_record_end > std::numeric_limits<uint16_t>::max()) { |
| 1152 | return OTS_FAILURE(); |
| 1153 | } |
| 1154 | std::vector<ScriptRecord> script_list; |
| 1155 | script_list.reserve(script_count); |
| 1156 | uint32_t last_tag = 0; |
| 1157 | for (unsigned i = 0; i < script_count; ++i) { |
| 1158 | if (!subtable.ReadU32(&script_list[i].tag) || |
| 1159 | !subtable.ReadU16(&script_list[i].offset)) { |
| 1160 | return OTS_FAILURE(); |
| 1161 | } |
| 1162 | // Script tags should be arranged alphabetically by tag |
| 1163 | if (last_tag != 0 && last_tag > script_list[i].tag) { |
| 1164 | return OTS_FAILURE(); |
| 1165 | } |
| 1166 | last_tag = script_list[i].tag; |
| 1167 | if (script_list[i].offset < script_record_end || |
| 1168 | script_list[i].offset >= length) { |
| 1169 | return OTS_FAILURE(); |
| 1170 | } |
| 1171 | } |
| 1172 | |
| 1173 | // Check script records. |
| 1174 | for (unsigned i = 0; i < script_count; ++i) { |
| 1175 | if (!ParseScriptTable(data + script_list[i].offset, |
| 1176 | length - script_list[i].offset, |
| 1177 | script_list[i].tag, num_features)) { |
| 1178 | return OTS_FAILURE(); |
| 1179 | } |
| 1180 | } |
| 1181 | |
| 1182 | return true; |
| 1183 | } |
| 1184 | |
| 1185 | // Parsing FeatureListTable requires number of lookups so we need to parse |
| 1186 | // LookupListTable before calling this function. |
| 1187 | bool ParseFeatureListTable(const uint8_t *data, const size_t length, |
| 1188 | const uint16_t num_lookups, |
| 1189 | uint16_t* num_features) { |
| 1190 | Buffer subtable(data, length); |
| 1191 | |
| 1192 | uint16_t feature_count = 0; |
| 1193 | if (!subtable.ReadU16(&feature_count)) { |
| 1194 | return OTS_FAILURE(); |
| 1195 | } |
| 1196 | |
| 1197 | std::vector<FeatureRecord> feature_records; |
| 1198 | feature_records.resize(feature_count); |
| 1199 | const unsigned feature_record_end = static_cast<unsigned>(2) + |
| 1200 | feature_count * 6; |
| 1201 | if (feature_record_end > std::numeric_limits<uint16_t>::max()) { |
| 1202 | return OTS_FAILURE(); |
| 1203 | } |
| 1204 | uint32_t last_tag = 0; |
| 1205 | for (unsigned i = 0; i < feature_count; ++i) { |
| 1206 | if (!subtable.ReadU32(&feature_records[i].tag) || |
| 1207 | !subtable.ReadU16(&feature_records[i].offset)) { |
| 1208 | return OTS_FAILURE(); |
| 1209 | } |
| 1210 | // Feature record array should be arranged alphabetically by tag |
| 1211 | if (last_tag != 0 && last_tag > feature_records[i].tag) { |
| 1212 | return OTS_FAILURE(); |
| 1213 | } |
| 1214 | last_tag = feature_records[i].tag; |
| 1215 | if (feature_records[i].offset < feature_record_end || |
| 1216 | feature_records[i].offset >= length) { |
| 1217 | return OTS_FAILURE(); |
| 1218 | } |
| 1219 | } |
| 1220 | |
| 1221 | for (unsigned i = 0; i < feature_count; ++i) { |
| 1222 | if (!ParseFeatureTable(data + feature_records[i].offset, |
| 1223 | length - feature_records[i].offset, num_lookups)) { |
| 1224 | return OTS_FAILURE(); |
| 1225 | } |
| 1226 | } |
| 1227 | *num_features = feature_count; |
| 1228 | return true; |
| 1229 | } |
| 1230 | |
| 1231 | // For parsing GPOS/GSUB tables, this function should be called at first to |
| 1232 | // obtain the number of lookups because parsing FeatureTableList requires |
| 1233 | // the number. |
| 1234 | bool ParseLookupListTable(OpenTypeFile *file, const uint8_t *data, |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 1235 | const size_t length, |
| 1236 | const LookupSubtableParser* parser, |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 1237 | uint16_t *num_lookups) { |
| 1238 | Buffer subtable(data, length); |
| 1239 | |
| 1240 | if (!subtable.ReadU16(num_lookups)) { |
| 1241 | return OTS_FAILURE(); |
| 1242 | } |
| 1243 | |
| 1244 | std::vector<uint16_t> lookups; |
| 1245 | lookups.reserve(*num_lookups); |
| 1246 | const unsigned lookup_end = static_cast<unsigned>(2) + |
| 1247 | (*num_lookups) * 2; |
| 1248 | if (lookup_end > std::numeric_limits<uint16_t>::max()) { |
| 1249 | return OTS_FAILURE(); |
| 1250 | } |
| 1251 | for (unsigned i = 0; i < *num_lookups; ++i) { |
| 1252 | if (!subtable.ReadU16(&lookups[i])) { |
| 1253 | return OTS_FAILURE(); |
| 1254 | } |
| 1255 | if (lookups[i] < lookup_end || lookups[i] >= length) { |
| 1256 | return OTS_FAILURE(); |
| 1257 | } |
| 1258 | } |
| 1259 | |
| 1260 | for (unsigned i = 0; i < *num_lookups; ++i) { |
| 1261 | if (!ParseLookupTable(file, data + lookups[i], length - lookups[i], |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 1262 | parser)) { |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 1263 | return OTS_FAILURE(); |
| 1264 | } |
| 1265 | } |
| 1266 | |
| 1267 | return true; |
| 1268 | } |
| 1269 | |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 1270 | bool ParseClassDefTable(const uint8_t *data, size_t length, |
| 1271 | const uint16_t num_glyphs, |
| 1272 | const uint16_t num_classes) { |
| 1273 | Buffer subtable(data, length); |
| 1274 | |
| 1275 | uint16_t format = 0; |
| 1276 | if (!subtable.ReadU16(&format)) { |
| 1277 | return OTS_FAILURE(); |
| 1278 | } |
| 1279 | if (format == 1) { |
| 1280 | return ParseClassDefFormat1(data, length, num_glyphs, num_classes); |
| 1281 | } else if (format == 2) { |
| 1282 | return ParseClassDefFormat2(data, length, num_glyphs, num_classes); |
| 1283 | } |
| 1284 | |
| 1285 | return OTS_FAILURE(); |
| 1286 | } |
| 1287 | |
| 1288 | bool ParseCoverageTable(const uint8_t *data, size_t length, |
| 1289 | const uint16_t num_glyphs) { |
| 1290 | Buffer subtable(data, length); |
| 1291 | |
| 1292 | uint16_t format = 0; |
| 1293 | if (!subtable.ReadU16(&format)) { |
| 1294 | return OTS_FAILURE(); |
| 1295 | } |
| 1296 | if (format == 1) { |
| 1297 | return ParseCoverageFormat1(data, length, num_glyphs); |
| 1298 | } else if (format == 2) { |
| 1299 | return ParseCoverageFormat2(data, length, num_glyphs); |
| 1300 | } |
| 1301 | |
| 1302 | return OTS_FAILURE(); |
| 1303 | } |
| 1304 | |
bashi@google.com | 78a8baa | 2011-02-07 06:21:25 +0000 | [diff] [blame] | 1305 | bool ParseDeviceTable(const uint8_t *data, size_t length) { |
| 1306 | Buffer subtable(data, length); |
| 1307 | |
| 1308 | uint16_t start_size = 0; |
| 1309 | uint16_t end_size = 0; |
| 1310 | uint16_t delta_format = 0; |
| 1311 | if (!subtable.ReadU16(&start_size) || |
| 1312 | !subtable.ReadU16(&end_size) || |
| 1313 | !subtable.ReadU16(&delta_format)) { |
| 1314 | return OTS_FAILURE(); |
| 1315 | } |
| 1316 | if (start_size > end_size) { |
| 1317 | OTS_WARNING("bad size range: %u > %u", start_size, end_size); |
| 1318 | return OTS_FAILURE(); |
| 1319 | } |
| 1320 | if (delta_format == 0 || delta_format > kMaxDeltaFormatType) { |
| 1321 | OTS_WARNING("bad delta format: %u", delta_format); |
| 1322 | return OTS_FAILURE(); |
| 1323 | } |
| 1324 | // The number of delta values per uint16. The device table should contain |
| 1325 | // at least |num_units| * 2 bytes compressed data. |
| 1326 | const unsigned num_units = (end_size - start_size) / |
| 1327 | (1 << (4 - delta_format)) + 1; |
| 1328 | // Just skip |num_units| * 2 bytes since the compressed data could take |
| 1329 | // arbitrary values. |
| 1330 | if (!subtable.Skip(num_units * 2)) { |
| 1331 | return OTS_FAILURE(); |
| 1332 | } |
| 1333 | return true; |
| 1334 | } |
| 1335 | |
bashi@chromium.org | ced7112 | 2011-02-17 10:23:47 +0000 | [diff] [blame^] | 1336 | bool ParseContextSubtable(const uint8_t *data, const size_t length, |
| 1337 | const uint16_t num_glyphs, |
| 1338 | const uint16_t num_lookups) { |
| 1339 | Buffer subtable(data, length); |
| 1340 | |
| 1341 | uint16_t format = 0; |
| 1342 | if (!subtable.ReadU16(&format)) { |
| 1343 | return OTS_FAILURE(); |
| 1344 | } |
| 1345 | |
| 1346 | if (format == 1) { |
| 1347 | if (!ParseContextFormat1(data, length, num_glyphs, num_lookups)) { |
| 1348 | return OTS_FAILURE(); |
| 1349 | } |
| 1350 | } else if (format == 2) { |
| 1351 | if (!ParseContextFormat2(data, length, num_glyphs, num_lookups)) { |
| 1352 | return OTS_FAILURE(); |
| 1353 | } |
| 1354 | } else if (format == 3) { |
| 1355 | if (!ParseContextFormat3(data, length, num_glyphs, num_lookups)) { |
| 1356 | return OTS_FAILURE(); |
| 1357 | } |
| 1358 | } else { |
| 1359 | return OTS_FAILURE(); |
| 1360 | } |
| 1361 | |
| 1362 | return true; |
| 1363 | } |
| 1364 | |
| 1365 | bool ParseChainingContextSubtable(const uint8_t *data, const size_t length, |
| 1366 | const uint16_t num_glyphs, |
| 1367 | const uint16_t num_lookups) { |
| 1368 | Buffer subtable(data, length); |
| 1369 | |
| 1370 | uint16_t format = 0; |
| 1371 | if (!subtable.ReadU16(&format)) { |
| 1372 | return OTS_FAILURE(); |
| 1373 | } |
| 1374 | |
| 1375 | if (format == 1) { |
| 1376 | if (!ParseChainContextFormat1(data, length, num_glyphs, num_lookups)) { |
| 1377 | return OTS_FAILURE(); |
| 1378 | } |
| 1379 | } else if (format == 2) { |
| 1380 | if (!ParseChainContextFormat2(data, length, num_glyphs, num_lookups)) { |
| 1381 | return OTS_FAILURE(); |
| 1382 | } |
| 1383 | } else if (format == 3) { |
| 1384 | if (!ParseChainContextFormat3(data, length, num_glyphs, num_lookups)) { |
| 1385 | return OTS_FAILURE(); |
| 1386 | } |
| 1387 | } else { |
| 1388 | return OTS_FAILURE(); |
| 1389 | } |
| 1390 | |
| 1391 | return true; |
| 1392 | } |
| 1393 | |
| 1394 | bool ParseExtensionSubtable(const OpenTypeFile *file, |
| 1395 | const uint8_t *data, const size_t length, |
| 1396 | const LookupSubtableParser* parser) { |
| 1397 | Buffer subtable(data, length); |
| 1398 | |
| 1399 | uint16_t format = 0; |
| 1400 | uint16_t lookup_type = 0; |
| 1401 | uint32_t offset_extension = 0; |
| 1402 | if (!subtable.ReadU16(&format) || |
| 1403 | !subtable.ReadU16(&lookup_type) || |
| 1404 | !subtable.ReadU32(&offset_extension)) { |
| 1405 | return OTS_FAILURE(); |
| 1406 | } |
| 1407 | |
| 1408 | if (format != 1) { |
| 1409 | return OTS_FAILURE(); |
| 1410 | } |
| 1411 | // |lookup_type| should be other than |parser->extension_type|. |
| 1412 | if (lookup_type < 1 || lookup_type > parser->num_types || |
| 1413 | lookup_type == parser->extension_type) { |
| 1414 | return OTS_FAILURE(); |
| 1415 | } |
| 1416 | |
| 1417 | const unsigned format_end = static_cast<unsigned>(8); |
| 1418 | if (offset_extension < format_end || |
| 1419 | offset_extension >= length) { |
| 1420 | return OTS_FAILURE(); |
| 1421 | } |
| 1422 | |
| 1423 | // Parse the extension subtable of |lookup_type|. |
| 1424 | if (!parser->Parse(file, data + offset_extension, length - offset_extension, |
| 1425 | lookup_type)) { |
| 1426 | return OTS_FAILURE(); |
| 1427 | } |
| 1428 | |
| 1429 | return true; |
| 1430 | } |
| 1431 | |
bashi@google.com | 00b790a | 2011-01-27 06:35:42 +0000 | [diff] [blame] | 1432 | } // namespace ots |
| 1433 | |