1 /*
2 * Copyright © 2007,2008,2009,2010 Red Hat, Inc.
3 * Copyright © 2012 Google, Inc.
4 *
5 * This is part of HarfBuzz, a text shaping library.
6 *
7 * Permission is hereby granted, without written agreement and without
8 * license or royalty fees, to use, copy, modify, and distribute this
9 * software and its documentation for any purpose, provided that the
10 * above copyright notice and the following two paragraphs appear in
11 * all copies of this software.
12 *
13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17 * DAMAGE.
18 *
19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24 *
25 * Red Hat Author(s): Behdad Esfahbod
26 * Google Author(s): Behdad Esfahbod
27 */
28
29 #ifndef HB_OPEN_TYPE_PRIVATE_HH
30 #define HB_OPEN_TYPE_PRIVATE_HH
31
32 #include "hb-private.hh"
33 #include "hb-debug.hh"
34 #include "hb-face-private.hh"
35
36
37 namespace OT {
38
39
40
41 /*
42 * Casts
43 */
44
45 /* Cast to struct T, reference to reference */
46 template<typename Type, typename TObject>
47 static inline const Type& CastR(const TObject &X)
48 { return reinterpret_cast<const Type&> (X); }
49 template<typename Type, typename TObject>
50 static inline Type& CastR(TObject &X)
51 { return reinterpret_cast<Type&> (X); }
52
53 /* Cast to struct T, pointer to pointer */
54 template<typename Type, typename TObject>
55 static inline const Type* CastP(const TObject *X)
56 { return reinterpret_cast<const Type*> (X); }
57 template<typename Type, typename TObject>
58 static inline Type* CastP(TObject *X)
59 { return reinterpret_cast<Type*> (X); }
60
61 /* StructAtOffset<T>(P,Ofs) returns the struct T& that is placed at memory
62 * location pointed to by P plus Ofs bytes. */
63 template<typename Type>
64 static inline const Type& StructAtOffset(const void *P, unsigned int offset)
65 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }
66 template<typename Type>
67 static inline Type& StructAtOffset(void *P, unsigned int offset)
68 { return * reinterpret_cast<Type*> ((char *) P + offset); }
69
70 /* StructAfter<T>(X) returns the struct T& that is placed after X.
71 * Works with X of variable size also. X must implement get_size() */
72 template<typename Type, typename TObject>
73 static inline const Type& StructAfter(const TObject &X)
74 { return StructAtOffset<Type>(&X, X.get_size()); }
75 template<typename Type, typename TObject>
76 static inline Type& StructAfter(TObject &X)
77 { return StructAtOffset<Type>(&X, X.get_size()); }
78
79
80
81 /*
82 * Size checking
83 */
84
85 /* Check _assertion in a method environment */
86 #define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \
87 inline void _instance_assertion_on_line_##_line (void) const \
88 { \
89 static_assert ((_assertion), ""); \
90 ASSERT_INSTANCE_POD (*this); /* Make sure it's POD. */ \
91 }
92 # define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)
93 # define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)
94
95 /* Check that _code compiles in a method environment */
96 #define _DEFINE_COMPILES_ASSERTION1(_line, _code) \
97 inline void _compiles_assertion_on_line_##_line (void) const \
98 { _code; }
99 # define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)
100 # define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)
101
102
103 #define DEFINE_SIZE_STATIC(size) \
104 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)); \
105 static const unsigned int static_size = (size); \
106 static const unsigned int min_size = (size); \
107 inline unsigned int get_size (void) const { return (size); }
108
109 #define DEFINE_SIZE_UNION(size, _member) \
110 DEFINE_INSTANCE_ASSERTION (0*sizeof(this->u._member.static_size) + sizeof(this->u._member) == (size)); \
111 static const unsigned int min_size = (size)
112
113 #define DEFINE_SIZE_MIN(size) \
114 DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)); \
115 static const unsigned int min_size = (size)
116
117 #define DEFINE_SIZE_ARRAY(size, array) \
118 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \
119 DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \
120 static const unsigned int min_size = (size)
121
122 #define DEFINE_SIZE_ARRAY2(size, array1, array2) \
123 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \
124 DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \
125 static const unsigned int min_size = (size)
126
127
128
129 /*
130 * Null objects
131 */
132
133 /* Global nul-content Null pool. Enlarge as necessary. */
134
135 #define HB_NULL_POOL_SIZE 264
136 static_assert (HB_NULL_POOL_SIZE % sizeof (void *) == 0, "Align HB_NULL_POOL_SIZE.");
137 extern HB_INTERNAL const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)];
138
139 /* Generic nul-content Null objects. */
140 template <typename Type>
141 static inline const Type& Null (void) {
142 static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
143 return *CastP<Type> (_hb_NullPool);
144 }
145
146 /* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
147 #define DEFINE_NULL_DATA(Type, data) \
148 static const char _Null##Type[sizeof (Type) + 1] = data; /* +1 is for nul-termination in data */ \
149 template <> \
150 /*static*/ inline const Type& Null<Type> (void) { \
151 return *CastP<Type> (_Null##Type); \
152 } /* The following line really exists such that we end in a place needing semicolon */ \
153 static_assert (Type::min_size + 1 <= sizeof (_Null##Type), "Null pool too small. Enlarge.")
154
155 /* Accessor macro. */
156 #define Null(Type) Null<Type>()
157
158
159 /*
160 * Dispatch
161 */
162
163 template <typename Context, typename Return, unsigned int MaxDebugDepth>
164 struct hb_dispatch_context_t
165 {
166 static const unsigned int max_debug_depth = MaxDebugDepth;
167 typedef Return return_t;
168 template <typename T, typename F>
169 inline bool may_dispatch (const T *obj, const F *format) { return true; }
170 static return_t no_dispatch_return_value (void) { return Context::default_return_value (); }
171 };
172
173
174 /*
175 * Sanitize
176 */
177
178 /* This limits sanitizing time on really broken fonts. */
179 #ifndef HB_SANITIZE_MAX_EDITS
180 #define HB_SANITIZE_MAX_EDITS 32
181 #endif
182
183 struct hb_sanitize_context_t :
184 hb_dispatch_context_t<hb_sanitize_context_t, bool, HB_DEBUG_SANITIZE>
185 {
186 inline hb_sanitize_context_t (void) :
187 debug_depth (0),
188 start (nullptr), end (nullptr),
189 writable (false), edit_count (0),
190 blob (nullptr) {}
191
192 inline const char *get_name (void) { return "SANITIZE"; }
193 template <typename T, typename F>
194 inline bool may_dispatch (const T *obj, const F *format)
195 { return format->sanitize (this); }
196 template <typename T>
197 inline return_t dispatch (const T &obj) { return obj.sanitize (this); }
198 static return_t default_return_value (void) { return true; }
199 static return_t no_dispatch_return_value (void) { return false; }
200 bool stop_sublookup_iteration (const return_t r) const { return !r; }
201
202 inline void init (hb_blob_t *b)
203 {
204 this->blob = hb_blob_reference (b);
205 this->writable = false;
206 }
207
208 inline void start_processing (void)
209 {
210 this->start = hb_blob_get_data (this->blob, nullptr);
211 this->end = this->start + hb_blob_get_length (this->blob);
212 assert (this->start <= this->end); /* Must not overflow. */
213 this->edit_count = 0;
214 this->debug_depth = 0;
215
216 DEBUG_MSG_LEVEL (SANITIZE, start, 0, +1,
217 "start [%p..%p] (%lu bytes)",
218 this->start, this->end,
219 (unsigned long) (this->end - this->start));
220 }
221
222 inline void end_processing (void)
223 {
224 DEBUG_MSG_LEVEL (SANITIZE, this->start, 0, -1,
225 "end [%p..%p] %u edit requests",
226 this->start, this->end, this->edit_count);
227
228 hb_blob_destroy (this->blob);
229 this->blob = nullptr;
230 this->start = this->end = nullptr;
231 }
232
233 inline bool check_range (const void *base, unsigned int len) const
234 {
235 const char *p = (const char *) base;
236 bool ok = this->start <= p && p <= this->end && (unsigned int) (this->end - p) >= len;
237
238 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
239 "check_range [%p..%p] (%d bytes) in [%p..%p] -> %s",
240 p, p + len, len,
241 this->start, this->end,
242 ok ? "OK" : "OUT-OF-RANGE");
243
244 return likely (ok);
245 }
246
247 inline bool check_array (const void *base, unsigned int record_size, unsigned int len) const
248 {
249 const char *p = (const char *) base;
250 bool overflows = _hb_unsigned_int_mul_overflows (len, record_size);
251 unsigned int array_size = record_size * len;
252 bool ok = !overflows && this->check_range (base, array_size);
253
254 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
255 "check_array [%p..%p] (%d*%d=%d bytes) in [%p..%p] -> %s",
256 p, p + (record_size * len), record_size, len, (unsigned int) array_size,
257 this->start, this->end,
258 overflows ? "OVERFLOWS" : ok ? "OK" : "OUT-OF-RANGE");
259
260 return likely (ok);
261 }
262
263 template <typename Type>
264 inline bool check_struct (const Type *obj) const
265 {
266 return likely (this->check_range (obj, obj->min_size));
267 }
268
269 inline bool may_edit (const void *base HB_UNUSED, unsigned int len HB_UNUSED)
270 {
271 if (this->edit_count >= HB_SANITIZE_MAX_EDITS)
272 return false;
273
274 const char *p = (const char *) base;
275 this->edit_count++;
276
277 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
278 "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",
279 this->edit_count,
280 p, p + len, len,
281 this->start, this->end,
282 this->writable ? "GRANTED" : "DENIED");
283
284 return this->writable;
285 }
286
287 template <typename Type, typename ValueType>
288 inline bool try_set (const Type *obj, const ValueType &v) {
289 if (this->may_edit (obj, obj->static_size)) {
290 const_cast<Type *> (obj)->set (v);
291 return true;
292 }
293 return false;
294 }
295
296 mutable unsigned int debug_depth;
297 const char *start, *end;
298 bool writable;
299 unsigned int edit_count;
300 hb_blob_t *blob;
301 };
302
303
304
305 /* Template to sanitize an object. */
306 template <typename Type>
307 struct Sanitizer
308 {
309 static hb_blob_t *sanitize (hb_blob_t *blob) {
310 hb_sanitize_context_t c[1];
311 bool sane;
312
313 /* TODO is_sane() stuff */
314
315 c->init (blob);
316
317 retry:
318 DEBUG_MSG_FUNC (SANITIZE, c->start, "start");
319
320 c->start_processing ();
321
322 if (unlikely (!c->start)) {
323 c->end_processing ();
324 return blob;
325 }
326
327 Type *t = CastP<Type> (const_cast<char *> (c->start));
328
329 sane = t->sanitize (c);
330 if (sane) {
331 if (c->edit_count) {
332 DEBUG_MSG_FUNC (SANITIZE, c->start, "passed first round with %d edits; going for second round", c->edit_count);
333
334 /* sanitize again to ensure no toe-stepping */
335 c->edit_count = 0;
336 sane = t->sanitize (c);
337 if (c->edit_count) {
338 DEBUG_MSG_FUNC (SANITIZE, c->start, "requested %d edits in second round; FAILLING", c->edit_count);
339 sane = false;
340 }
341 }
342 } else {
343 unsigned int edit_count = c->edit_count;
344 if (edit_count && !c->writable) {
345 c->start = hb_blob_get_data_writable (blob, nullptr);
346 c->end = c->start + hb_blob_get_length (blob);
347
348 if (c->start) {
349 c->writable = true;
350 /* ok, we made it writable by relocating. try again */
351 DEBUG_MSG_FUNC (SANITIZE, c->start, "retry");
352 goto retry;
353 }
354 }
355 }
356
357 c->end_processing ();
358
359 DEBUG_MSG_FUNC (SANITIZE, c->start, sane ? "PASSED" : "FAILED");
360 if (sane)
361 return blob;
362 else {
363 hb_blob_destroy (blob);
364 return hb_blob_get_empty ();
365 }
366 }
367
368 static const Type* lock_instance (hb_blob_t *blob) {
369 hb_blob_make_immutable (blob);
370 const char *base = hb_blob_get_data (blob, nullptr);
371 return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
372 }
373 };
374
375
376
377 /*
378 * Serialize
379 */
380
381
382 struct hb_serialize_context_t
383 {
384 inline hb_serialize_context_t (void *start_, unsigned int size)
385 {
386 this->start = (char *) start_;
387 this->end = this->start + size;
388
389 this->ran_out_of_room = false;
390 this->head = this->start;
391 this->debug_depth = 0;
392 }
393
394 template <typename Type>
395 inline Type *start_serialize (void)
396 {
397 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, +1,
398 "start [%p..%p] (%lu bytes)",
399 this->start, this->end,
400 (unsigned long) (this->end - this->start));
401
402 return start_embed<Type> ();
403 }
404
405 inline void end_serialize (void)
406 {
407 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, -1,
408 "end [%p..%p] serialized %d bytes; %s",
409 this->start, this->end,
410 (int) (this->head - this->start),
411 this->ran_out_of_room ? "RAN OUT OF ROOM" : "did not ran out of room");
412
413 }
414
415 template <typename Type>
416 inline Type *copy (void)
417 {
418 assert (!this->ran_out_of_room);
419 unsigned int len = this->head - this->start;
420 void *p = malloc (len);
421 if (p)
422 memcpy (p, this->start, len);
423 return reinterpret_cast<Type *> (p);
424 }
425
426 template <typename Type>
427 inline Type *allocate_size (unsigned int size)
428 {
429 if (unlikely (this->ran_out_of_room || this->end - this->head < ptrdiff_t (size))) {
430 this->ran_out_of_room = true;
431 return nullptr;
432 }
433 memset (this->head, 0, size);
434 char *ret = this->head;
435 this->head += size;
436 return reinterpret_cast<Type *> (ret);
437 }
438
439 template <typename Type>
440 inline Type *allocate_min (void)
441 {
442 return this->allocate_size<Type> (Type::min_size);
443 }
444
445 template <typename Type>
446 inline Type *start_embed (void)
447 {
448 Type *ret = reinterpret_cast<Type *> (this->head);
449 return ret;
450 }
451
452 template <typename Type>
453 inline Type *embed (const Type &obj)
454 {
455 unsigned int size = obj.get_size ();
456 Type *ret = this->allocate_size<Type> (size);
457 if (unlikely (!ret)) return nullptr;
458 memcpy (ret, obj, size);
459 return ret;
460 }
461
462 template <typename Type>
463 inline Type *extend_min (Type &obj)
464 {
465 unsigned int size = obj.min_size;
466 assert (this->start <= (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
467 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return nullptr;
468 return reinterpret_cast<Type *> (&obj);
469 }
470
471 template <typename Type>
472 inline Type *extend (Type &obj)
473 {
474 unsigned int size = obj.get_size ();
475 assert (this->start < (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
476 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return nullptr;
477 return reinterpret_cast<Type *> (&obj);
478 }
479
480 inline void truncate (void *new_head)
481 {
482 assert (this->start < new_head && new_head <= this->head);
483 this->head = (char *) new_head;
484 }
485
486 unsigned int debug_depth;
487 char *start, *end, *head;
488 bool ran_out_of_room;
489 };
490
491 template <typename Type>
492 struct Supplier
493 {
494 inline Supplier (const Type *array, unsigned int len_)
495 {
496 head = array;
497 len = len_;
498 }
499 inline const Type operator [] (unsigned int i) const
500 {
501 if (unlikely (i >= len)) return Type ();
502 return head[i];
503 }
504
505 inline void advance (unsigned int count)
506 {
507 if (unlikely (count > len))
508 count = len;
509 len -= count;
510 head += count;
511 }
512
513 private:
514 inline Supplier (const Supplier<Type> &); /* Disallow copy */
515 inline Supplier<Type>& operator= (const Supplier<Type> &); /* Disallow copy */
516
517 unsigned int len;
518 const Type *head;
519 };
520
521
522
523
524 /*
525 *
526 * The OpenType Font File: Data Types
527 */
528
529
530 /* "The following data types are used in the OpenType font file.
531 * All OpenType fonts use Motorola-style byte ordering (Big Endian):" */
532
533 /*
534 * Int types
535 */
536
537
538 template <typename Type, int Bytes> struct BEInt;
539
540 template <typename Type>
541 struct BEInt<Type, 1>
542 {
543 public:
544 inline void set (Type V)
545 {
546 v = V;
547 }
548 inline operator Type (void) const
549 {
550 return v;
551 }
552 private: uint8_t v;
553 };
554 template <typename Type>
555 struct BEInt<Type, 2>
556 {
557 public:
558 inline void set (Type V)
559 {
560 v[0] = (V >> 8) & 0xFF;
561 v[1] = (V ) & 0xFF;
562 }
563 inline operator Type (void) const
564 {
565 return (v[0] << 8)
566 + (v[1] );
567 }
568 private: uint8_t v[2];
569 };
570 template <typename Type>
571 struct BEInt<Type, 3>
572 {
573 public:
574 inline void set (Type V)
575 {
576 v[0] = (V >> 16) & 0xFF;
577 v[1] = (V >> 8) & 0xFF;
578 v[2] = (V ) & 0xFF;
579 }
580 inline operator Type (void) const
581 {
582 return (v[0] << 16)
583 + (v[1] << 8)
584 + (v[2] );
585 }
586 private: uint8_t v[3];
587 };
588 template <typename Type>
589 struct BEInt<Type, 4>
590 {
591 public:
592 inline void set (Type V)
593 {
594 v[0] = (V >> 24) & 0xFF;
595 v[1] = (V >> 16) & 0xFF;
596 v[2] = (V >> 8) & 0xFF;
597 v[3] = (V ) & 0xFF;
598 }
599 inline operator Type (void) const
600 {
601 return (v[0] << 24)
602 + (v[1] << 16)
603 + (v[2] << 8)
604 + (v[3] );
605 }
606 private: uint8_t v[4];
607 };
608
609 /* Integer types in big-endian order and no alignment requirement */
610 template <typename Type, unsigned int Size>
611 struct IntType
612 {
613 inline void set (Type i) { v.set (i); }
614 inline operator Type(void) const { return v; }
615 inline bool operator == (const IntType<Type,Size> &o) const { return (Type) v == (Type) o.v; }
616 inline bool operator != (const IntType<Type,Size> &o) const { return !(*this == o); }
617 static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }
618 template <typename Type2>
619 inline int cmp (Type2 a) const
620 {
621 Type b = v;
622 if (sizeof (Type) < sizeof (int) && sizeof (Type2) < sizeof (int))
623 return (int) a - (int) b;
624 else
625 return a < b ? -1 : a == b ? 0 : +1;
626 }
627 inline bool sanitize (hb_sanitize_context_t *c) const
628 {
629 TRACE_SANITIZE (this);
630 return_trace (likely (c->check_struct (this)));
631 }
632 protected:
633 BEInt<Type, Size> v;
634 public:
635 DEFINE_SIZE_STATIC (Size);
636 };
637
638 typedef IntType<int8_t, 1> CHAR; /* 8-bit signed integer. */
639 typedef IntType<uint8_t, 1> BYTE; /* 8-bit unsigned integer. */
640 typedef IntType<int8_t, 1> INT8; /* 8-bit signed integer. */
641 typedef IntType<uint16_t, 2> USHORT; /* 16-bit unsigned integer. */
642 typedef IntType<int16_t, 2> SHORT; /* 16-bit signed integer. */
643 typedef IntType<uint32_t, 4> ULONG; /* 32-bit unsigned integer. */
644 typedef IntType<int32_t, 4> LONG; /* 32-bit signed integer. */
645 typedef IntType<uint32_t, 3> UINT24; /* 24-bit unsigned integer. */
646
647 /* 16-bit signed integer (SHORT) that describes a quantity in FUnits. */
648 typedef SHORT FWORD;
649
650 /* 16-bit unsigned integer (USHORT) that describes a quantity in FUnits. */
651 typedef USHORT UFWORD;
652
653 /* 16-bit signed fixed number with the low 14 bits of fraction (2.14). */
654 struct F2DOT14 : SHORT
655 {
656 //inline float to_float (void) const { return ???; }
657 //inline void set_float (float f) { v.set (f * ???); }
658 public:
659 DEFINE_SIZE_STATIC (2);
660 };
661
662 /* 32-bit signed fixed-point number (16.16). */
663 struct Fixed: LONG
664 {
665 //inline float to_float (void) const { return ???; }
666 //inline void set_float (float f) { v.set (f * ???); }
667 public:
668 DEFINE_SIZE_STATIC (4);
669 };
670
671 /* Date represented in number of seconds since 12:00 midnight, January 1,
672 * 1904. The value is represented as a signed 64-bit integer. */
673 struct LONGDATETIME
674 {
675 inline bool sanitize (hb_sanitize_context_t *c) const
676 {
677 TRACE_SANITIZE (this);
678 return_trace (likely (c->check_struct (this)));
679 }
680 protected:
681 LONG major;
682 ULONG minor;
683 public:
684 DEFINE_SIZE_STATIC (8);
685 };
686
687 /* Array of four uint8s (length = 32 bits) used to identify a script, language
688 * system, feature, or baseline */
689 struct Tag : ULONG
690 {
691 /* What the char* converters return is NOT nul-terminated. Print using "%.4s" */
692 inline operator const char* (void) const { return reinterpret_cast<const char *> (&this->v); }
693 inline operator char* (void) { return reinterpret_cast<char *> (&this->v); }
694 public:
695 DEFINE_SIZE_STATIC (4);
696 };
697 DEFINE_NULL_DATA (Tag, " ");
698
699 /* Glyph index number, same as uint16 (length = 16 bits) */
700 typedef USHORT GlyphID;
701
702 /* Script/language-system/feature index */
703 struct Index : USHORT {
704 static const unsigned int NOT_FOUND_INDEX = 0xFFFFu;
705 };
706 DEFINE_NULL_DATA (Index, "\xff\xff");
707
708 /* Offset, Null offset = 0 */
709 template <typename Type=USHORT>
710 struct Offset : Type
711 {
712 inline bool is_null (void) const { return 0 == *this; }
713 public:
714 DEFINE_SIZE_STATIC (sizeof(Type));
715 };
716
717
718 /* CheckSum */
719 struct CheckSum : ULONG
720 {
721 /* This is reference implementation from the spec. */
722 static inline uint32_t CalcTableChecksum (const ULONG *Table, uint32_t Length)
723 {
724 uint32_t Sum = 0L;
725 const ULONG *EndPtr = Table+((Length+3) & ~3) / ULONG::static_size;
726
727 while (Table < EndPtr)
728 Sum += *Table++;
729 return Sum;
730 }
731
732 /* Note: data should be 4byte aligned and have 4byte padding at the end. */
733 inline void set_for_data (const void *data, unsigned int length)
734 { set (CalcTableChecksum ((const ULONG *) data, length)); }
735
736 public:
737 DEFINE_SIZE_STATIC (4);
738 };
739
740
741 /*
742 * Version Numbers
743 */
744
745 template <typename FixedType=USHORT>
746 struct FixedVersion
747 {
748 inline uint32_t to_int (void) const { return (major << (sizeof(FixedType) * 8)) + minor; }
749
750 inline bool sanitize (hb_sanitize_context_t *c) const
751 {
752 TRACE_SANITIZE (this);
753 return_trace (c->check_struct (this));
754 }
755
756 FixedType major;
757 FixedType minor;
758 public:
759 DEFINE_SIZE_STATIC (2 * sizeof(FixedType));
760 };
761
762
763
764 /*
765 * Template subclasses of Offset that do the dereferencing.
766 * Use: (base+offset)
767 */
768
769 template <typename Type, typename OffsetType=USHORT>
770 struct OffsetTo : Offset<OffsetType>
771 {
772 inline const Type& operator () (const void *base) const
773 {
774 unsigned int offset = *this;
775 if (unlikely (!offset)) return Null(Type);
776 return StructAtOffset<Type> (base, offset);
777 }
778
779 inline Type& serialize (hb_serialize_context_t *c, const void *base)
780 {
781 Type *t = c->start_embed<Type> ();
782 this->set ((char *) t - (char *) base); /* TODO(serialize) Overflow? */
783 return *t;
784 }
785
786 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
787 {
788 TRACE_SANITIZE (this);
789 if (unlikely (!c->check_struct (this))) return_trace (false);
790 unsigned int offset = *this;
791 if (unlikely (!offset)) return_trace (true);
792 if (unlikely (!c->check_range (base, offset))) return_trace (false);
793 const Type &obj = StructAtOffset<Type> (base, offset);
794 return_trace (likely (obj.sanitize (c)) || neuter (c));
795 }
796 template <typename T>
797 inline bool sanitize (hb_sanitize_context_t *c, const void *base, T user_data) const
798 {
799 TRACE_SANITIZE (this);
800 if (unlikely (!c->check_struct (this))) return_trace (false);
801 unsigned int offset = *this;
802 if (unlikely (!offset)) return_trace (true);
803 if (unlikely (!c->check_range (base, offset))) return_trace (false);
804 const Type &obj = StructAtOffset<Type> (base, offset);
805 return_trace (likely (obj.sanitize (c, user_data)) || neuter (c));
806 }
807
808 /* Set the offset to Null */
809 inline bool neuter (hb_sanitize_context_t *c) const {
810 return c->try_set (this, 0);
811 }
812 DEFINE_SIZE_STATIC (sizeof(OffsetType));
813 };
814 template <typename Type> struct LOffsetTo : OffsetTo<Type, ULONG> {};
815 template <typename Base, typename OffsetType, typename Type>
816 static inline const Type& operator + (const Base &base, const OffsetTo<Type, OffsetType> &offset) { return offset (base); }
817 template <typename Base, typename OffsetType, typename Type>
818 static inline Type& operator + (Base &base, OffsetTo<Type, OffsetType> &offset) { return offset (base); }
819
820
821 /*
822 * Array Types
823 */
824
825 /* An array with a number of elements. */
826 template <typename Type, typename LenType=USHORT>
827 struct ArrayOf
828 {
829 const Type *sub_array (unsigned int start_offset, unsigned int *pcount /* IN/OUT */) const
830 {
831 unsigned int count = len;
832 if (unlikely (start_offset > count))
833 count = 0;
834 else
835 count -= start_offset;
836 count = MIN (count, *pcount);
837 *pcount = count;
838 return array + start_offset;
839 }
840
841 inline const Type& operator [] (unsigned int i) const
842 {
843 if (unlikely (i >= len)) return Null(Type);
844 return array[i];
845 }
846 inline Type& operator [] (unsigned int i)
847 {
848 return array[i];
849 }
850 inline unsigned int get_size (void) const
851 { return len.static_size + len * Type::static_size; }
852
853 inline bool serialize (hb_serialize_context_t *c,
854 unsigned int items_len)
855 {
856 TRACE_SERIALIZE (this);
857 if (unlikely (!c->extend_min (*this))) return_trace (false);
858 len.set (items_len); /* TODO(serialize) Overflow? */
859 if (unlikely (!c->extend (*this))) return_trace (false);
860 return_trace (true);
861 }
862
863 inline bool serialize (hb_serialize_context_t *c,
864 Supplier<Type> &items,
865 unsigned int items_len)
866 {
867 TRACE_SERIALIZE (this);
868 if (unlikely (!serialize (c, items_len))) return_trace (false);
869 for (unsigned int i = 0; i < items_len; i++)
870 array[i] = items[i];
871 items.advance (items_len);
872 return_trace (true);
873 }
874
875 inline bool sanitize (hb_sanitize_context_t *c) const
876 {
877 TRACE_SANITIZE (this);
878 if (unlikely (!sanitize_shallow (c))) return_trace (false);
879
880 /* Note: for structs that do not reference other structs,
881 * we do not need to call their sanitize() as we already did
882 * a bound check on the aggregate array size. We just include
883 * a small unreachable expression to make sure the structs
884 * pointed to do have a simple sanitize(), ie. they do not
885 * reference other structs via offsets.
886 */
887 (void) (false && array[0].sanitize (c));
888
889 return_trace (true);
890 }
891 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
892 {
893 TRACE_SANITIZE (this);
894 if (unlikely (!sanitize_shallow (c))) return_trace (false);
895 unsigned int count = len;
896 for (unsigned int i = 0; i < count; i++)
897 if (unlikely (!array[i].sanitize (c, base)))
898 return_trace (false);
899 return_trace (true);
900 }
901 template <typename T>
902 inline bool sanitize (hb_sanitize_context_t *c, const void *base, T user_data) const
903 {
904 TRACE_SANITIZE (this);
905 if (unlikely (!sanitize_shallow (c))) return_trace (false);
906 unsigned int count = len;
907 for (unsigned int i = 0; i < count; i++)
908 if (unlikely (!array[i].sanitize (c, base, user_data)))
909 return_trace (false);
910 return_trace (true);
911 }
912
913 template <typename SearchType>
914 inline int lsearch (const SearchType &x) const
915 {
916 unsigned int count = len;
917 for (unsigned int i = 0; i < count; i++)
918 if (!this->array[i].cmp (x))
919 return i;
920 return -1;
921 }
922
923 private:
924 inline bool sanitize_shallow (hb_sanitize_context_t *c) const
925 {
926 TRACE_SANITIZE (this);
927 return_trace (len.sanitize (c) && c->check_array (array, Type::static_size, len));
928 }
929
930 public:
931 LenType len;
932 Type array[VAR];
933 public:
934 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
935 };
936 template <typename Type> struct LArrayOf : ArrayOf<Type, ULONG> {};
937
938 /* Array of Offset's */
939 template <typename Type, typename OffsetType=USHORT>
940 struct OffsetArrayOf : ArrayOf<OffsetTo<Type, OffsetType> > {};
941
942 /* Array of offsets relative to the beginning of the array itself. */
943 template <typename Type>
944 struct OffsetListOf : OffsetArrayOf<Type>
945 {
946 inline const Type& operator [] (unsigned int i) const
947 {
948 if (unlikely (i >= this->len)) return Null(Type);
949 return this+this->array[i];
950 }
951
952 inline bool sanitize (hb_sanitize_context_t *c) const
953 {
954 TRACE_SANITIZE (this);
955 return_trace (OffsetArrayOf<Type>::sanitize (c, this));
956 }
957 template <typename T>
958 inline bool sanitize (hb_sanitize_context_t *c, T user_data) const
959 {
960 TRACE_SANITIZE (this);
961 return_trace (OffsetArrayOf<Type>::sanitize (c, this, user_data));
962 }
963 };
964
965
966 /* An array starting at second element. */
967 template <typename Type, typename LenType=USHORT>
968 struct HeadlessArrayOf
969 {
970 inline const Type& operator [] (unsigned int i) const
971 {
972 if (unlikely (i >= len || !i)) return Null(Type);
973 return array[i-1];
974 }
975 inline unsigned int get_size (void) const
976 { return len.static_size + (len ? len - 1 : 0) * Type::static_size; }
977
978 inline bool serialize (hb_serialize_context_t *c,
979 Supplier<Type> &items,
980 unsigned int items_len)
981 {
982 TRACE_SERIALIZE (this);
983 if (unlikely (!c->extend_min (*this))) return_trace (false);
984 len.set (items_len); /* TODO(serialize) Overflow? */
985 if (unlikely (!items_len)) return_trace (true);
986 if (unlikely (!c->extend (*this))) return_trace (false);
987 for (unsigned int i = 0; i < items_len - 1; i++)
988 array[i] = items[i];
989 items.advance (items_len - 1);
990 return_trace (true);
991 }
992
993 inline bool sanitize (hb_sanitize_context_t *c) const
994 {
995 TRACE_SANITIZE (this);
996 if (unlikely (!sanitize_shallow (c))) return_trace (false);
997
998 /* Note: for structs that do not reference other structs,
999 * we do not need to call their sanitize() as we already did
1000 * a bound check on the aggregate array size. We just include
1001 * a small unreachable expression to make sure the structs
1002 * pointed to do have a simple sanitize(), ie. they do not
1003 * reference other structs via offsets.
1004 */
1005 (void) (false && array[0].sanitize (c));
1006
1007 return_trace (true);
1008 }
1009
1010 private:
1011 inline bool sanitize_shallow (hb_sanitize_context_t *c) const
1012 {
1013 TRACE_SANITIZE (this);
1014 return_trace (len.sanitize (c) &&
1015 (!len || c->check_array (array, Type::static_size, len - 1)));
1016 }
1017
1018 public:
1019 LenType len;
1020 Type array[VAR];
1021 public:
1022 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
1023 };
1024
1025
1026 /*
1027 * An array with sorted elements. Supports binary searching.
1028 */
1029 template <typename Type, typename LenType=USHORT>
1030 struct SortedArrayOf : ArrayOf<Type, LenType>
1031 {
1032 template <typename SearchType>
1033 inline int bsearch (const SearchType &x) const
1034 {
1035 /* Hand-coded bsearch here since this is in the hot inner loop. */
1036 const Type *array = this->array;
1037 int min = 0, max = (int) this->len - 1;
1038 while (min <= max)
1039 {
1040 int mid = (min + max) / 2;
1041 int c = array[mid].cmp (x);
1042 if (c < 0)
1043 max = mid - 1;
1044 else if (c > 0)
1045 min = mid + 1;
1046 else
1047 return mid;
1048 }
1049 return -1;
1050 }
1051 };
1052
1053 /*
1054 * Binary-search arrays
1055 */
1056
1057 struct BinSearchHeader
1058 {
1059 inline operator uint32_t (void) const { return len; }
1060
1061 inline bool sanitize (hb_sanitize_context_t *c) const
1062 {
1063 TRACE_SANITIZE (this);
1064 return_trace (c->check_struct (this));
1065 }
1066
1067 protected:
1068 USHORT len;
1069 USHORT searchRangeZ;
1070 USHORT entrySelectorZ;
1071 USHORT rangeShiftZ;
1072
1073 public:
1074 DEFINE_SIZE_STATIC (8);
1075 };
1076
1077 template <typename Type>
1078 struct BinSearchArrayOf : SortedArrayOf<Type, BinSearchHeader> {};
1079
1080
1081 /* Lazy struct and blob loaders. */
1082
1083 /* Logic is shared between hb_lazy_loader_t and hb_lazy_table_loader_t */
1084 template <typename T>
1085 struct hb_lazy_loader_t
1086 {
1087 inline void init (hb_face_t *face_)
1088 {
1089 face = face_;
1090 instance = nullptr;
1091 }
1092
1093 inline void fini (void)
1094 {
1095 if (instance && instance != &OT::Null(T))
1096 {
1097 instance->fini();
1098 free (instance);
1099 }
1100 }
1101
1102 inline const T* get (void) const
1103 {
1104 retry:
1105 T *p = (T *) hb_atomic_ptr_get (&instance);
1106 if (unlikely (!p))
1107 {
1108 p = (T *) calloc (1, sizeof (T));
1109 if (unlikely (!p))
1110 p = const_cast<T *> (&OT::Null(T));
1111 else
1112 p->init (face);
1113 if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p)))
1114 {
1115 if (p != &OT::Null(T))
1116 p->fini ();
1117 goto retry;
1118 }
1119 }
1120 return p;
1121 }
1122
1123 inline const T* operator-> (void) const
1124 {
1125 return get ();
1126 }
1127
1128 private:
1129 hb_face_t *face;
1130 T *instance;
1131 };
1132
1133 /* Logic is shared between hb_lazy_loader_t and hb_lazy_table_loader_t */
1134 template <typename T>
1135 struct hb_lazy_table_loader_t
1136 {
1137 inline void init (hb_face_t *face_)
1138 {
1139 face = face_;
1140 instance = nullptr;
1141 blob = nullptr;
1142 }
1143
1144 inline void fini (void)
1145 {
1146 hb_blob_destroy (blob);
1147 }
1148
1149 inline const T* get (void) const
1150 {
1151 retry:
1152 T *p = (T *) hb_atomic_ptr_get (&instance);
1153 if (unlikely (!p))
1154 {
1155 hb_blob_t *blob_ = OT::Sanitizer<T>::sanitize (face->reference_table (T::tableTag));
1156 p = const_cast<T *>(OT::Sanitizer<T>::lock_instance (blob_));
1157 if (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p))
1158 {
1159 hb_blob_destroy (blob_);
1160 goto retry;
1161 }
1162 blob = blob_;
1163 }
1164 return p;
1165 }
1166
1167 inline const T* operator-> (void) const
1168 {
1169 return get();
1170 }
1171
1172 private:
1173 hb_face_t *face;
1174 T *instance;
1175 mutable hb_blob_t *blob;
1176 };
1177
1178
1179 } /* namespace OT */
1180
1181
1182 #endif /* HB_OPEN_TYPE_PRIVATE_HH */