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[chromium-blink-merge.git] / third_party / harfbuzz-ng / src / hb-ot-cmap-table.hh
blob048231255387177aa6251e181f253a57ec16dba7
1 /*
2 * Copyright © 2014 Google, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod
25 */
26
27 #ifndef HB_OT_CMAP_TABLE_HH
28 #define HB_OT_CMAP_TABLE_HH
29
30 #include "hb-open-type-private.hh"
31
32
33 namespace OT {
34
35
36 /*
37 * cmap -- Character To Glyph Index Mapping Table
38 */
39
40 #define HB_OT_TAG_cmap HB_TAG('c','m','a','p')
41
42
43 struct CmapSubtableFormat0
44 {
45 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
46 {
47 hb_codepoint_t gid = codepoint < 256 ? glyphIdArray[codepoint] : 0;
48 if (!gid)
49 return false;
50 *glyph = gid;
51 return true;
52 }
53
54 inline bool sanitize (hb_sanitize_context_t *c) const
55 {
56 TRACE_SANITIZE (this);
57 return TRACE_RETURN (c->check_struct (this));
58 }
59
60 protected:
61 USHORT format; /* Format number is set to 0. */
62 USHORT lengthZ; /* Byte length of this subtable. */
63 USHORT languageZ; /* Ignore. */
64 BYTE glyphIdArray[256];/* An array that maps character
65 * code to glyph index values. */
66 public:
67 DEFINE_SIZE_STATIC (6 + 256);
68 };
69
70 struct CmapSubtableFormat4
71 {
72 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
73 {
74 unsigned int segCount;
75 const USHORT *endCount;
76 const USHORT *startCount;
77 const USHORT *idDelta;
78 const USHORT *idRangeOffset;
79 const USHORT *glyphIdArray;
80 unsigned int glyphIdArrayLength;
81
82 segCount = this->segCountX2 / 2;
83 endCount = this->values;
84 startCount = endCount + segCount + 1;
85 idDelta = startCount + segCount;
86 idRangeOffset = idDelta + segCount;
87 glyphIdArray = idRangeOffset + segCount;
88 glyphIdArrayLength = (this->length - 16 - 8 * segCount) / 2;
89
90 /* Custom two-array bsearch. */
91 int min = 0, max = (int) segCount - 1;
92 unsigned int i;
93 while (min <= max)
94 {
95 int mid = (min + max) / 2;
96 if (codepoint < startCount[mid])
97 max = mid - 1;
98 else if (codepoint > endCount[mid])
99 min = mid + 1;
100 else
101 {
102 i = mid;
103 goto found;
104 }
105 }
106 return false;
107
108 found:
109 hb_codepoint_t gid;
110 unsigned int rangeOffset = idRangeOffset[i];
111 if (rangeOffset == 0)
112 gid = codepoint + idDelta[i];
113 else
114 {
115 /* Somebody has been smoking... */
116 unsigned int index = rangeOffset / 2 + (codepoint - startCount[i]) + i - segCount;
117 if (unlikely (index >= glyphIdArrayLength))
118 return false;
119 gid = glyphIdArray[index];
120 if (unlikely (!gid))
121 return false;
122 gid += idDelta[i];
123 }
124
125 *glyph = gid & 0xFFFFu;
126 return true;
127 }
128
129 inline bool sanitize (hb_sanitize_context_t *c) const
130 {
131 TRACE_SANITIZE (this);
132 if (unlikely (!c->check_struct (this)))
133 return TRACE_RETURN (false);
134
135 if (unlikely (!c->check_range (this, length)))
136 {
137 /* Some broken fonts have too long of a "length" value.
138 * If that is the case, just change the value to truncate
139 * the subtable at the end of the blob. */
140 uint16_t new_length = (uint16_t) MIN ((uintptr_t) 65535,
141 (uintptr_t) (c->end -
142 (char *) this));
143 if (!c->try_set (&length, new_length))
144 return TRACE_RETURN (false);
145 }
146
147 return TRACE_RETURN (16 + 4 * (unsigned int) segCountX2 <= length);
148 }
149
150 protected:
151 USHORT format; /* Format number is set to 4. */
152 USHORT length; /* This is the length in bytes of the
153 * subtable. */
154 USHORT languageZ; /* Ignore. */
155 USHORT segCountX2; /* 2 x segCount. */
156 USHORT searchRangeZ; /* 2 * (2**floor(log2(segCount))) */
157 USHORT entrySelectorZ; /* log2(searchRange/2) */
158 USHORT rangeShiftZ; /* 2 x segCount - searchRange */
159
160 USHORT values[VAR];
161 #if 0
162 USHORT endCount[segCount]; /* End characterCode for each segment,
163 * last=0xFFFFu. */
164 USHORT reservedPad; /* Set to 0. */
165 USHORT startCount[segCount]; /* Start character code for each segment. */
166 SHORT idDelta[segCount]; /* Delta for all character codes in segment. */
167 USHORT idRangeOffset[segCount];/* Offsets into glyphIdArray or 0 */
168 USHORT glyphIdArray[VAR]; /* Glyph index array (arbitrary length) */
169 #endif
170
171 public:
172 DEFINE_SIZE_ARRAY (14, values);
173 };
174
175 struct CmapSubtableLongGroup
176 {
177 friend struct CmapSubtableFormat12;
178 friend struct CmapSubtableFormat13;
179
180 int cmp (hb_codepoint_t codepoint) const
181 {
182 if (codepoint < startCharCode) return -1;
183 if (codepoint > endCharCode) return +1;
184 return 0;
185 }
186
187 inline bool sanitize (hb_sanitize_context_t *c) const
188 {
189 TRACE_SANITIZE (this);
190 return TRACE_RETURN (c->check_struct (this));
191 }
192
193 private:
194 ULONG startCharCode; /* First character code in this group. */
195 ULONG endCharCode; /* Last character code in this group. */
196 ULONG glyphID; /* Glyph index; interpretation depends on
197 * subtable format. */
198 public:
199 DEFINE_SIZE_STATIC (12);
200 };
201
202 template <typename UINT>
203 struct CmapSubtableTrimmed
204 {
205 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
206 {
207 /* Rely on our implicit array bound-checking. */
208 hb_codepoint_t gid = glyphIdArray[codepoint - startCharCode];
209 if (!gid)
210 return false;
211 *glyph = gid;
212 return true;
213 }
214
215 inline bool sanitize (hb_sanitize_context_t *c) const
216 {
217 TRACE_SANITIZE (this);
218 return TRACE_RETURN (c->check_struct (this) && glyphIdArray.sanitize (c));
219 }
220
221 protected:
222 UINT formatReserved; /* Subtable format and (maybe) padding. */
223 UINT lengthZ; /* Byte length of this subtable. */
224 UINT languageZ; /* Ignore. */
225 UINT startCharCode; /* First character code covered. */
226 ArrayOf<GlyphID, UINT>
227 glyphIdArray; /* Array of glyph index values for character
228 * codes in the range. */
229 public:
230 DEFINE_SIZE_ARRAY (5 * sizeof (UINT), glyphIdArray);
231 };
232
233 struct CmapSubtableFormat6 : CmapSubtableTrimmed<USHORT> {};
234 struct CmapSubtableFormat10 : CmapSubtableTrimmed<ULONG > {};
235
236 template <typename T>
237 struct CmapSubtableLongSegmented
238 {
239 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
240 {
241 int i = groups.bsearch (codepoint);
242 if (i == -1)
243 return false;
244 *glyph = T::group_get_glyph (groups[i], codepoint);
245 return true;
246 }
247
248 inline bool sanitize (hb_sanitize_context_t *c) const
249 {
250 TRACE_SANITIZE (this);
251 return TRACE_RETURN (c->check_struct (this) && groups.sanitize (c));
252 }
253
254 protected:
255 USHORT format; /* Subtable format; set to 12. */
256 USHORT reservedZ; /* Reserved; set to 0. */
257 ULONG lengthZ; /* Byte length of this subtable. */
258 ULONG languageZ; /* Ignore. */
259 SortedArrayOf<CmapSubtableLongGroup, ULONG>
260 groups; /* Groupings. */
261 public:
262 DEFINE_SIZE_ARRAY (16, groups);
263 };
264
265 struct CmapSubtableFormat12 : CmapSubtableLongSegmented<CmapSubtableFormat12>
266 {
267 static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
268 hb_codepoint_t u)
269 { return group.glyphID + (u - group.startCharCode); }
270 };
271
272 struct CmapSubtableFormat13 : CmapSubtableLongSegmented<CmapSubtableFormat13>
273 {
274 static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
275 hb_codepoint_t u HB_UNUSED)
276 { return group.glyphID; }
277 };
278
279 typedef enum
280 {
281 GLYPH_VARIANT_NOT_FOUND = 0,
282 GLYPH_VARIANT_FOUND = 1,
283 GLYPH_VARIANT_USE_DEFAULT = 2
284 } glyph_variant_t;
285
286 struct UnicodeValueRange
287 {
288 inline int cmp (const hb_codepoint_t &codepoint) const
289 {
290 if (codepoint < startUnicodeValue) return -1;
291 if (codepoint > startUnicodeValue + additionalCount) return +1;
292 return 0;
293 }
294
295 inline bool sanitize (hb_sanitize_context_t *c) const
296 {
297 TRACE_SANITIZE (this);
298 return TRACE_RETURN (c->check_struct (this));
299 }
300
301 UINT24 startUnicodeValue; /* First value in this range. */
302 BYTE additionalCount; /* Number of additional values in this
303 * range. */
304 public:
305 DEFINE_SIZE_STATIC (4);
306 };
307
308 typedef SortedArrayOf<UnicodeValueRange, ULONG> DefaultUVS;
309
310 struct UVSMapping
311 {
312 inline int cmp (const hb_codepoint_t &codepoint) const
313 {
314 return unicodeValue.cmp (codepoint);
315 }
316
317 inline bool sanitize (hb_sanitize_context_t *c) const
318 {
319 TRACE_SANITIZE (this);
320 return TRACE_RETURN (c->check_struct (this));
321 }
322
323 UINT24 unicodeValue; /* Base Unicode value of the UVS */
324 GlyphID glyphID; /* Glyph ID of the UVS */
325 public:
326 DEFINE_SIZE_STATIC (5);
327 };
328
329 typedef SortedArrayOf<UVSMapping, ULONG> NonDefaultUVS;
330
331 struct VariationSelectorRecord
332 {
333 inline glyph_variant_t get_glyph (hb_codepoint_t codepoint,
334 hb_codepoint_t *glyph,
335 const void *base) const
336 {
337 int i;
338 const DefaultUVS &defaults = base+defaultUVS;
339 i = defaults.bsearch (codepoint);
340 if (i != -1)
341 return GLYPH_VARIANT_USE_DEFAULT;
342 const NonDefaultUVS &nonDefaults = base+nonDefaultUVS;
343 i = nonDefaults.bsearch (codepoint);
344 if (i != -1)
345 {
346 *glyph = nonDefaults[i].glyphID;
347 return GLYPH_VARIANT_FOUND;
348 }
349 return GLYPH_VARIANT_NOT_FOUND;
350 }
351
352 inline int cmp (const hb_codepoint_t &variation_selector) const
353 {
354 return varSelector.cmp (variation_selector);
355 }
356
357 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
358 {
359 TRACE_SANITIZE (this);
360 return TRACE_RETURN (c->check_struct (this) &&
361 defaultUVS.sanitize (c, base) &&
362 nonDefaultUVS.sanitize (c, base));
363 }
364
365 UINT24 varSelector; /* Variation selector. */
366 OffsetTo<DefaultUVS, ULONG>
367 defaultUVS; /* Offset to Default UVS Table. May be 0. */
368 OffsetTo<NonDefaultUVS, ULONG>
369 nonDefaultUVS; /* Offset to Non-Default UVS Table. May be 0. */
370 public:
371 DEFINE_SIZE_STATIC (11);
372 };
373
374 struct CmapSubtableFormat14
375 {
376 inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
377 hb_codepoint_t variation_selector,
378 hb_codepoint_t *glyph) const
379 {
380 return record[record.bsearch(variation_selector)].get_glyph (codepoint, glyph, this);
381 }
382
383 inline bool sanitize (hb_sanitize_context_t *c) const
384 {
385 TRACE_SANITIZE (this);
386 return TRACE_RETURN (c->check_struct (this) &&
387 record.sanitize (c, this));
388 }
389
390 protected:
391 USHORT format; /* Format number is set to 0. */
392 ULONG lengthZ; /* Byte length of this subtable. */
393 SortedArrayOf<VariationSelectorRecord, ULONG>
394 record; /* Variation selector records; sorted
395 * in increasing order of `varSelector'. */
396 public:
397 DEFINE_SIZE_ARRAY (10, record);
398 };
399
400 struct CmapSubtable
401 {
402 /* Note: We intentionally do NOT implement subtable formats 2 and 8. */
403
404 inline bool get_glyph (hb_codepoint_t codepoint,
405 hb_codepoint_t *glyph) const
406 {
407 switch (u.format) {
408 case 0: return u.format0 .get_glyph(codepoint, glyph);
409 case 4: return u.format4 .get_glyph(codepoint, glyph);
410 case 6: return u.format6 .get_glyph(codepoint, glyph);
411 case 10: return u.format10.get_glyph(codepoint, glyph);
412 case 12: return u.format12.get_glyph(codepoint, glyph);
413 case 13: return u.format13.get_glyph(codepoint, glyph);
414 case 14:
415 default: return false;
416 }
417 }
418
419 inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
420 hb_codepoint_t variation_selector,
421 hb_codepoint_t *glyph) const
422 {
423 switch (u.format) {
424 case 14: return u.format14.get_glyph_variant(codepoint, variation_selector, glyph);
425 default: return GLYPH_VARIANT_NOT_FOUND;
426 }
427 }
428
429 inline bool sanitize (hb_sanitize_context_t *c) const
430 {
431 TRACE_SANITIZE (this);
432 if (!u.format.sanitize (c)) return TRACE_RETURN (false);
433 switch (u.format) {
434 case 0: return TRACE_RETURN (u.format0 .sanitize (c));
435 case 4: return TRACE_RETURN (u.format4 .sanitize (c));
436 case 6: return TRACE_RETURN (u.format6 .sanitize (c));
437 case 10: return TRACE_RETURN (u.format10.sanitize (c));
438 case 12: return TRACE_RETURN (u.format12.sanitize (c));
439 case 13: return TRACE_RETURN (u.format13.sanitize (c));
440 case 14: return TRACE_RETURN (u.format14.sanitize (c));
441 default:return TRACE_RETURN (true);
442 }
443 }
444
445 protected:
446 union {
447 USHORT format; /* Format identifier */
448 CmapSubtableFormat0 format0;
449 CmapSubtableFormat4 format4;
450 CmapSubtableFormat6 format6;
451 CmapSubtableFormat10 format10;
452 CmapSubtableFormat12 format12;
453 CmapSubtableFormat13 format13;
454 CmapSubtableFormat14 format14;
455 } u;
456 public:
457 DEFINE_SIZE_UNION (2, format);
458 };
459
460
461 struct EncodingRecord
462 {
463 inline int cmp (const EncodingRecord &other) const
464 {
465 int ret;
466 ret = platformID.cmp (other.platformID);
467 if (ret) return ret;
468 ret = encodingID.cmp (other.encodingID);
469 if (ret) return ret;
470 return 0;
471 }
472
473 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
474 {
475 TRACE_SANITIZE (this);
476 return TRACE_RETURN (c->check_struct (this) &&
477 subtable.sanitize (c, base));
478 }
479
480 USHORT platformID; /* Platform ID. */
481 USHORT encodingID; /* Platform-specific encoding ID. */
482 OffsetTo<CmapSubtable, ULONG>
483 subtable; /* Byte offset from beginning of table to the subtable for this encoding. */
484 public:
485 DEFINE_SIZE_STATIC (8);
486 };
487
488 struct cmap
489 {
490 static const hb_tag_t tableTag = HB_OT_TAG_cmap;
491
492 inline const CmapSubtable *find_subtable (unsigned int platform_id,
493 unsigned int encoding_id) const
494 {
495 EncodingRecord key;
496 key.platformID.set (platform_id);
497 key.encodingID.set (encoding_id);
498
499 /* Note: We can use bsearch, but since it has no performance
500 * implications, we use lsearch and as such accept fonts with
501 * unsorted subtable list. */
502 int result = encodingRecord./*bsearch*/lsearch (key);
503 if (result == -1 || !encodingRecord[result].subtable)
504 return NULL;
505
506 return &(this+encodingRecord[result].subtable);
507 }
508
509 inline bool sanitize (hb_sanitize_context_t *c) const
510 {
511 TRACE_SANITIZE (this);
512 return TRACE_RETURN (c->check_struct (this) &&
513 likely (version == 0) &&
514 encodingRecord.sanitize (c, this));
515 }
516
517 USHORT version; /* Table version number (0). */
518 SortedArrayOf<EncodingRecord>
519 encodingRecord; /* Encoding tables. */
520 public:
521 DEFINE_SIZE_ARRAY (4, encodingRecord);
522 };
523
524
525 } /* namespace OT */
526
527
528 #endif /* HB_OT_CMAP_TABLE_HH */