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 (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 struct accelerator_t
73 {
74 inline void init (const CmapSubtableFormat4 *subtable)
75 {
76 segCount = subtable->segCountX2 / 2;
77 endCount = subtable->values;
78 startCount = endCount + segCount + 1;
79 idDelta = startCount + segCount;
80 idRangeOffset = idDelta + segCount;
81 glyphIdArray = idRangeOffset + segCount;
82 glyphIdArrayLength = (subtable->length - 16 - 8 * segCount) / 2;
83 }
84
85 static inline bool get_glyph_func (const void *obj, hb_codepoint_t codepoint, hb_codepoint_t *glyph)
86 {
87 const accelerator_t *thiz = (const accelerator_t *) obj;
88
89 /* Custom two-array bsearch. */
90 int min = 0, max = (int) thiz->segCount - 1;
91 const USHORT *startCount = thiz->startCount;
92 const USHORT *endCount = thiz->endCount;
93 unsigned int i;
94 while (min <= max)
95 {
96 int mid = (min + max) / 2;
97 if (codepoint < startCount[mid])
98 max = mid - 1;
99 else if (codepoint > endCount[mid])
100 min = mid + 1;
101 else
102 {
103 i = mid;
104 goto found;
105 }
106 }
107 return false;
108
109 found:
110 hb_codepoint_t gid;
111 unsigned int rangeOffset = thiz->idRangeOffset[i];
112 if (rangeOffset == 0)
113 gid = codepoint + thiz->idDelta[i];
114 else
115 {
116 /* Somebody has been smoking... */
117 unsigned int index = rangeOffset / 2 + (codepoint - thiz->startCount[i]) + i - thiz->segCount;
118 if (unlikely (index >= thiz->glyphIdArrayLength))
119 return false;
120 gid = thiz->glyphIdArray[index];
121 if (unlikely (!gid))
122 return false;
123 gid += thiz->idDelta[i];
124 }
125
126 *glyph = gid & 0xFFFFu;
127 return true;
128 }
129
130 const USHORT *endCount;
131 const USHORT *startCount;
132 const USHORT *idDelta;
133 const USHORT *idRangeOffset;
134 const USHORT *glyphIdArray;
135 unsigned int segCount;
136 unsigned int glyphIdArrayLength;
137 };
138
139 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
140 {
141 accelerator_t accel;
142 accel.init (this);
143 return accel.get_glyph_func (&accel, codepoint, glyph);
144 }
145
146 inline bool sanitize (hb_sanitize_context_t *c) const
147 {
148 TRACE_SANITIZE (this);
149 if (unlikely (!c->check_struct (this)))
150 return_trace (false);
151
152 if (unlikely (!c->check_range (this, length)))
153 {
154 /* Some broken fonts have too long of a "length" value.
155 * If that is the case, just change the value to truncate
156 * the subtable at the end of the blob. */
157 uint16_t new_length = (uint16_t) MIN ((uintptr_t) 65535,
158 (uintptr_t) (c->end -
159 (char *) this));
160 if (!c->try_set (&length, new_length))
161 return_trace (false);
162 }
163
164 return_trace (16 + 4 * (unsigned int) segCountX2 <= length);
165 }
166
167 protected:
168 USHORT format; /* Format number is set to 4. */
169 USHORT length; /* This is the length in bytes of the
170 * subtable. */
171 USHORT languageZ; /* Ignore. */
172 USHORT segCountX2; /* 2 x segCount. */
173 USHORT searchRangeZ; /* 2 * (2**floor(log2(segCount))) */
174 USHORT entrySelectorZ; /* log2(searchRange/2) */
175 USHORT rangeShiftZ; /* 2 x segCount - searchRange */
176
177 USHORT values[VAR];
178 #if 0
179 USHORT endCount[segCount]; /* End characterCode for each segment,
180 * last=0xFFFFu. */
181 USHORT reservedPad; /* Set to 0. */
182 USHORT startCount[segCount]; /* Start character code for each segment. */
183 SHORT idDelta[segCount]; /* Delta for all character codes in segment. */
184 USHORT idRangeOffset[segCount];/* Offsets into glyphIdArray or 0 */
185 USHORT glyphIdArray[VAR]; /* Glyph index array (arbitrary length) */
186 #endif
187
188 public:
189 DEFINE_SIZE_ARRAY (14, values);
190 };
191
192 struct CmapSubtableLongGroup
193 {
194 friend struct CmapSubtableFormat12;
195 friend struct CmapSubtableFormat13;
196
197 int cmp (hb_codepoint_t codepoint) const
198 {
199 if (codepoint < startCharCode) return -1;
200 if (codepoint > endCharCode) return +1;
201 return 0;
202 }
203
204 inline bool sanitize (hb_sanitize_context_t *c) const
205 {
206 TRACE_SANITIZE (this);
207 return_trace (c->check_struct (this));
208 }
209
210 private:
211 ULONG startCharCode; /* First character code in this group. */
212 ULONG endCharCode; /* Last character code in this group. */
213 ULONG glyphID; /* Glyph index; interpretation depends on
214 * subtable format. */
215 public:
216 DEFINE_SIZE_STATIC (12);
217 };
218
219 template <typename UINT>
220 struct CmapSubtableTrimmed
221 {
222 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
223 {
224 /* Rely on our implicit array bound-checking. */
225 hb_codepoint_t gid = glyphIdArray[codepoint - startCharCode];
226 if (!gid)
227 return false;
228 *glyph = gid;
229 return true;
230 }
231
232 inline bool sanitize (hb_sanitize_context_t *c) const
233 {
234 TRACE_SANITIZE (this);
235 return_trace (c->check_struct (this) && glyphIdArray.sanitize (c));
236 }
237
238 protected:
239 UINT formatReserved; /* Subtable format and (maybe) padding. */
240 UINT lengthZ; /* Byte length of this subtable. */
241 UINT languageZ; /* Ignore. */
242 UINT startCharCode; /* First character code covered. */
243 ArrayOf<GlyphID, UINT>
244 glyphIdArray; /* Array of glyph index values for character
245 * codes in the range. */
246 public:
247 DEFINE_SIZE_ARRAY (5 * sizeof (UINT), glyphIdArray);
248 };
249
250 struct CmapSubtableFormat6 : CmapSubtableTrimmed<USHORT> {};
251 struct CmapSubtableFormat10 : CmapSubtableTrimmed<ULONG > {};
252
253 template <typename T>
254 struct CmapSubtableLongSegmented
255 {
256 inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
257 {
258 int i = groups.bsearch (codepoint);
259 if (i == -1)
260 return false;
261 *glyph = T::group_get_glyph (groups[i], codepoint);
262 return true;
263 }
264
265 inline bool sanitize (hb_sanitize_context_t *c) const
266 {
267 TRACE_SANITIZE (this);
268 return_trace (c->check_struct (this) && groups.sanitize (c));
269 }
270
271 protected:
272 USHORT format; /* Subtable format; set to 12. */
273 USHORT reservedZ; /* Reserved; set to 0. */
274 ULONG lengthZ; /* Byte length of this subtable. */
275 ULONG languageZ; /* Ignore. */
276 SortedArrayOf<CmapSubtableLongGroup, ULONG>
277 groups; /* Groupings. */
278 public:
279 DEFINE_SIZE_ARRAY (16, groups);
280 };
281
282 struct CmapSubtableFormat12 : CmapSubtableLongSegmented<CmapSubtableFormat12>
283 {
284 static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
285 hb_codepoint_t u)
286 { return group.glyphID + (u - group.startCharCode); }
287 };
288
289 struct CmapSubtableFormat13 : CmapSubtableLongSegmented<CmapSubtableFormat13>
290 {
291 static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
292 hb_codepoint_t u HB_UNUSED)
293 { return group.glyphID; }
294 };
295
296 typedef enum
297 {
298 GLYPH_VARIANT_NOT_FOUND = 0,
299 GLYPH_VARIANT_FOUND = 1,
300 GLYPH_VARIANT_USE_DEFAULT = 2
301 } glyph_variant_t;
302
303 struct UnicodeValueRange
304 {
305 inline int cmp (const hb_codepoint_t &codepoint) const
306 {
307 if (codepoint < startUnicodeValue) return -1;
308 if (codepoint > startUnicodeValue + additionalCount) return +1;
309 return 0;
310 }
311
312 inline bool sanitize (hb_sanitize_context_t *c) const
313 {
314 TRACE_SANITIZE (this);
315 return_trace (c->check_struct (this));
316 }
317
318 UINT24 startUnicodeValue; /* First value in this range. */
319 BYTE additionalCount; /* Number of additional values in this
320 * range. */
321 public:
322 DEFINE_SIZE_STATIC (4);
323 };
324
325 typedef SortedArrayOf<UnicodeValueRange, ULONG> DefaultUVS;
326
327 struct UVSMapping
328 {
329 inline int cmp (const hb_codepoint_t &codepoint) const
330 {
331 return unicodeValue.cmp (codepoint);
332 }
333
334 inline bool sanitize (hb_sanitize_context_t *c) const
335 {
336 TRACE_SANITIZE (this);
337 return_trace (c->check_struct (this));
338 }
339
340 UINT24 unicodeValue; /* Base Unicode value of the UVS */
341 GlyphID glyphID; /* Glyph ID of the UVS */
342 public:
343 DEFINE_SIZE_STATIC (5);
344 };
345
346 typedef SortedArrayOf<UVSMapping, ULONG> NonDefaultUVS;
347
348 struct VariationSelectorRecord
349 {
350 inline glyph_variant_t get_glyph (hb_codepoint_t codepoint,
351 hb_codepoint_t *glyph,
352 const void *base) const
353 {
354 int i;
355 const DefaultUVS &defaults = base+defaultUVS;
356 i = defaults.bsearch (codepoint);
357 if (i != -1)
358 return GLYPH_VARIANT_USE_DEFAULT;
359 const NonDefaultUVS &nonDefaults = base+nonDefaultUVS;
360 i = nonDefaults.bsearch (codepoint);
361 if (i != -1)
362 {
363 *glyph = nonDefaults[i].glyphID;
364 return GLYPH_VARIANT_FOUND;
365 }
366 return GLYPH_VARIANT_NOT_FOUND;
367 }
368
369 inline int cmp (const hb_codepoint_t &variation_selector) const
370 {
371 return varSelector.cmp (variation_selector);
372 }
373
374 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
375 {
376 TRACE_SANITIZE (this);
377 return_trace (c->check_struct (this) &&
378 defaultUVS.sanitize (c, base) &&
379 nonDefaultUVS.sanitize (c, base));
380 }
381
382 UINT24 varSelector; /* Variation selector. */
383 LOffsetTo<DefaultUVS>
384 defaultUVS; /* Offset to Default UVS Table. May be 0. */
385 LOffsetTo<NonDefaultUVS>
386 nonDefaultUVS; /* Offset to Non-Default UVS Table. May be 0. */
387 public:
388 DEFINE_SIZE_STATIC (11);
389 };
390
391 struct CmapSubtableFormat14
392 {
393 inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
394 hb_codepoint_t variation_selector,
395 hb_codepoint_t *glyph) const
396 {
397 return record[record.bsearch(variation_selector)].get_glyph (codepoint, glyph, this);
398 }
399
400 inline bool sanitize (hb_sanitize_context_t *c) const
401 {
402 TRACE_SANITIZE (this);
403 return_trace (c->check_struct (this) &&
404 record.sanitize (c, this));
405 }
406
407 protected:
408 USHORT format; /* Format number is set to 14. */
409 ULONG lengthZ; /* Byte length of this subtable. */
410 SortedArrayOf<VariationSelectorRecord, ULONG>
411 record; /* Variation selector records; sorted
412 * in increasing order of `varSelector'. */
413 public:
414 DEFINE_SIZE_ARRAY (10, record);
415 };
416
417 struct CmapSubtable
418 {
419 /* Note: We intentionally do NOT implement subtable formats 2 and 8. */
420
421 inline bool get_glyph (hb_codepoint_t codepoint,
422 hb_codepoint_t *glyph) const
423 {
424 switch (u.format) {
425 case 0: return u.format0 .get_glyph(codepoint, glyph);
426 case 4: return u.format4 .get_glyph(codepoint, glyph);
427 case 6: return u.format6 .get_glyph(codepoint, glyph);
428 case 10: return u.format10.get_glyph(codepoint, glyph);
429 case 12: return u.format12.get_glyph(codepoint, glyph);
430 case 13: return u.format13.get_glyph(codepoint, glyph);
431 case 14:
432 default: return false;
433 }
434 }
435
436 inline bool sanitize (hb_sanitize_context_t *c) const
437 {
438 TRACE_SANITIZE (this);
439 if (!u.format.sanitize (c)) return_trace (false);
440 switch (u.format) {
441 case 0: return_trace (u.format0 .sanitize (c));
442 case 4: return_trace (u.format4 .sanitize (c));
443 case 6: return_trace (u.format6 .sanitize (c));
444 case 10: return_trace (u.format10.sanitize (c));
445 case 12: return_trace (u.format12.sanitize (c));
446 case 13: return_trace (u.format13.sanitize (c));
447 case 14: return_trace (u.format14.sanitize (c));
448 default:return_trace (true);
449 }
450 }
451
452 public:
453 union {
454 USHORT format; /* Format identifier */
455 CmapSubtableFormat0 format0;
456 CmapSubtableFormat4 format4;
457 CmapSubtableFormat6 format6;
458 CmapSubtableFormat10 format10;
459 CmapSubtableFormat12 format12;
460 CmapSubtableFormat13 format13;
461 CmapSubtableFormat14 format14;
462 } u;
463 public:
464 DEFINE_SIZE_UNION (2, format);
465 };
466
467
468 struct EncodingRecord
469 {
470 inline int cmp (const EncodingRecord &other) const
471 {
472 int ret;
473 ret = platformID.cmp (other.platformID);
474 if (ret) return ret;
475 ret = encodingID.cmp (other.encodingID);
476 if (ret) return ret;
477 return 0;
478 }
479
480 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
481 {
482 TRACE_SANITIZE (this);
483 return_trace (c->check_struct (this) &&
484 subtable.sanitize (c, base));
485 }
486
487 USHORT platformID; /* Platform ID. */
488 USHORT encodingID; /* Platform-specific encoding ID. */
489 LOffsetTo<CmapSubtable>
490 subtable; /* Byte offset from beginning of table to the subtable for this encoding. */
491 public:
492 DEFINE_SIZE_STATIC (8);
493 };
494
495 struct cmap
496 {
497 static const hb_tag_t tableTag = HB_OT_TAG_cmap;
498
499 inline const CmapSubtable *find_subtable (unsigned int platform_id,
500 unsigned int encoding_id) const
501 {
502 EncodingRecord key;
503 key.platformID.set (platform_id);
504 key.encodingID.set (encoding_id);
505
506 /* Note: We can use bsearch, but since it has no performance
507 * implications, we use lsearch and as such accept fonts with
508 * unsorted subtable list. */
509 int result = encodingRecord./*bsearch*/lsearch (key);
510 if (result == -1 || !encodingRecord[result].subtable)
511 return nullptr;
512
513 return &(this+encodingRecord[result].subtable);
514 }
515
516 inline bool sanitize (hb_sanitize_context_t *c) const
517 {
518 TRACE_SANITIZE (this);
519 return_trace (c->check_struct (this) &&
520 likely (version == 0) &&
521 encodingRecord.sanitize (c, this));
522 }
523
524 USHORT version; /* Table version number (0). */
525 SortedArrayOf<EncodingRecord>
526 encodingRecord; /* Encoding tables. */
527 public:
528 DEFINE_SIZE_ARRAY (4, encodingRecord);
529 };
530
531
532 } /* namespace OT */
533
534
535 #endif /* HB_OT_CMAP_TABLE_HH */