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comparison: gfx/harfbuzz/src/hb-open-type-private.hh

gfx/harfbuzz/src/hb-open-type-private.hh

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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
34
35 namespace OT {
36
37
38
39 /*
40 * Casts
41 */
42
43 /* Cast to struct T, reference to reference */
44 template<typename Type, typename TObject>
45 inline const Type& CastR(const TObject &X)
46 { return reinterpret_cast<const Type&> (X); }
47 template<typename Type, typename TObject>
48 inline Type& CastR(TObject &X)
49 { return reinterpret_cast<Type&> (X); }
50
51 /* Cast to struct T, pointer to pointer */
52 template<typename Type, typename TObject>
53 inline const Type* CastP(const TObject *X)
54 { return reinterpret_cast<const Type*> (X); }
55 template<typename Type, typename TObject>
56 inline Type* CastP(TObject *X)
57 { return reinterpret_cast<Type*> (X); }
58
59 /* StructAtOffset<T>(P,Ofs) returns the struct T& that is placed at memory
60 * location pointed to by P plus Ofs bytes. */
61 template<typename Type>
62 inline const Type& StructAtOffset(const void *P, unsigned int offset)
63 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }
64 template<typename Type>
65 inline Type& StructAtOffset(void *P, unsigned int offset)
66 { return * reinterpret_cast<Type*> ((char *) P + offset); }
67
68 /* StructAfter<T>(X) returns the struct T& that is placed after X.
69 * Works with X of variable size also. X must implement get_size() */
70 template<typename Type, typename TObject>
71 inline const Type& StructAfter(const TObject &X)
72 { return StructAtOffset<Type>(&X, X.get_size()); }
73 template<typename Type, typename TObject>
74 inline Type& StructAfter(TObject &X)
75 { return StructAtOffset<Type>(&X, X.get_size()); }
76
77
78
79 /*
80 * Size checking
81 */
82
83 /* Check _assertion in a method environment */
84 #define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \
85 inline void _instance_assertion_on_line_##_line (void) const \
86 { \
87 ASSERT_STATIC (_assertion); \
88 ASSERT_INSTANCE_POD (*this); /* Make sure it's POD. */ \
89 }
90 # define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)
91 # define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)
92
93 /* Check that _code compiles in a method environment */
94 #define _DEFINE_COMPILES_ASSERTION1(_line, _code) \
95 inline void _compiles_assertion_on_line_##_line (void) const \
96 { _code; }
97 # define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)
98 # define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)
99
100
101 #define DEFINE_SIZE_STATIC(size) \
102 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)); \
103 static const unsigned int static_size = (size); \
104 static const unsigned int min_size = (size)
105
106 /* Size signifying variable-sized array */
107 #define VAR 1
108
109 #define DEFINE_SIZE_UNION(size, _member) \
110 DEFINE_INSTANCE_ASSERTION (this->u._member.static_size == (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 /* TODO This really should be a extern HB_INTERNAL and defined somewhere... */
135 static const void *_NullPool[64 / sizeof (void *)];
136
137 /* Generic nul-content Null objects. */
138 template <typename Type>
139 static inline const Type& Null (void) {
140 ASSERT_STATIC (sizeof (Type) <= sizeof (_NullPool));
141 return *CastP<Type> (_NullPool);
142 }
143
144 /* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
145 #define DEFINE_NULL_DATA(Type, data) \
146 static const char _Null##Type[sizeof (Type) + 1] = data; /* +1 is for nul-termination in data */ \
147 template <> \
148 inline const Type& Null<Type> (void) { \
149 return *CastP<Type> (_Null##Type); \
150 } /* The following line really exists such that we end in a place needing semicolon */ \
151 ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))
152
153 /* Accessor macro. */
154 #define Null(Type) Null<Type>()
155
156
157
158 /*
159 * Sanitize
160 */
161
162 #ifndef HB_DEBUG_SANITIZE
163 #define HB_DEBUG_SANITIZE (HB_DEBUG+0)
164 #endif
165
166
167 #define TRACE_SANITIZE(this) \
168 hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace \
169 (&c->debug_depth, c->get_name (), this, HB_FUNC, \
170 "");
171
172 /* This limits sanitizing time on really broken fonts. */
173 #ifndef HB_SANITIZE_MAX_EDITS
174 #define HB_SANITIZE_MAX_EDITS 100
175 #endif
176
177 struct hb_sanitize_context_t
178 {
179 inline const char *get_name (void) { return "SANITIZE"; }
180 static const unsigned int max_debug_depth = HB_DEBUG_SANITIZE;
181 typedef bool return_t;
182 template <typename T>
183 inline return_t dispatch (const T &obj) { return obj.sanitize (this); }
184 static return_t default_return_value (void) { return true; }
185 bool stop_sublookup_iteration (const return_t r HB_UNUSED) const { return false; }
186
187 inline void init (hb_blob_t *b)
188 {
189 this->blob = hb_blob_reference (b);
190 this->writable = false;
191 }
192
193 inline void start_processing (void)
194 {
195 this->start = hb_blob_get_data (this->blob, NULL);
196 this->end = this->start + hb_blob_get_length (this->blob);
197 this->edit_count = 0;
198 this->debug_depth = 0;
199
200 DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, +1,
201 "start [%p..%p] (%lu bytes)",
202 this->start, this->end,
203 (unsigned long) (this->end - this->start));
204 }
205
206 inline void end_processing (void)
207 {
208 DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, -1,
209 "end [%p..%p] %u edit requests",
210 this->start, this->end, this->edit_count);
211
212 hb_blob_destroy (this->blob);
213 this->blob = NULL;
214 this->start = this->end = NULL;
215 }
216
217 inline bool check_range (const void *base, unsigned int len) const
218 {
219 const char *p = (const char *) base;
220
221 hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace
222 (&this->debug_depth, "SANITIZE", this->blob, NULL,
223 "check_range [%p..%p] (%d bytes) in [%p..%p]",
224 p, p + len, len,
225 this->start, this->end);
226
227 return TRACE_RETURN (likely (this->start <= p && p <= this->end && (unsigned int) (this->end - p) >= len));
228 }
229
230 inline bool check_array (const void *base, unsigned int record_size, unsigned int len) const
231 {
232 const char *p = (const char *) base;
233 bool overflows = _hb_unsigned_int_mul_overflows (len, record_size);
234
235 hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace
236 (&this->debug_depth, "SANITIZE", this->blob, NULL,
237 "check_array [%p..%p] (%d*%d=%ld bytes) in [%p..%p]",
238 p, p + (record_size * len), record_size, len, (unsigned long) record_size * len,
239 this->start, this->end);
240
241 return TRACE_RETURN (likely (!overflows && this->check_range (base, record_size * len)));
242 }
243
244 template <typename Type>
245 inline bool check_struct (const Type *obj) const
246 {
247 return likely (this->check_range (obj, obj->min_size));
248 }
249
250 inline bool may_edit (const void *base HB_UNUSED, unsigned int len HB_UNUSED)
251 {
252 if (this->edit_count >= HB_SANITIZE_MAX_EDITS)
253 return false;
254
255 const char *p = (const char *) base;
256 this->edit_count++;
257
258 hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace
259 (&this->debug_depth, "SANITIZE", this->blob, NULL,
260 "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",
261 this->edit_count,
262 p, p + len, len,
263 this->start, this->end,
264 this->writable ? "GRANTED" : "DENIED");
265
266 return TRACE_RETURN (this->writable);
267 }
268
269 mutable unsigned int debug_depth;
270 const char *start, *end;
271 bool writable;
272 unsigned int edit_count;
273 hb_blob_t *blob;
274 };
275
276
277
278 /* Template to sanitize an object. */
279 template <typename Type>
280 struct Sanitizer
281 {
282 static hb_blob_t *sanitize (hb_blob_t *blob) {
283 hb_sanitize_context_t c[1] = {{0}};
284 bool sane;
285
286 /* TODO is_sane() stuff */
287
288 c->init (blob);
289
290 retry:
291 DEBUG_MSG_FUNC (SANITIZE, blob, "start");
292
293 c->start_processing ();
294
295 if (unlikely (!c->start)) {
296 c->end_processing ();
297 return blob;
298 }
299
300 Type *t = CastP<Type> (const_cast<char *> (c->start));
301
302 sane = t->sanitize (c);
303 if (sane) {
304 if (c->edit_count) {
305 DEBUG_MSG_FUNC (SANITIZE, blob, "passed first round with %d edits; going for second round", c->edit_count);
306
307 /* sanitize again to ensure no toe-stepping */
308 c->edit_count = 0;
309 sane = t->sanitize (c);
310 if (c->edit_count) {
311 DEBUG_MSG_FUNC (SANITIZE, blob, "requested %d edits in second round; FAILLING", c->edit_count);
312 sane = false;
313 }
314 }
315 } else {
316 unsigned int edit_count = c->edit_count;
317 if (edit_count && !c->writable) {
318 c->start = hb_blob_get_data_writable (blob, NULL);
319 c->end = c->start + hb_blob_get_length (blob);
320
321 if (c->start) {
322 c->writable = true;
323 /* ok, we made it writable by relocating. try again */
324 DEBUG_MSG_FUNC (SANITIZE, blob, "retry");
325 goto retry;
326 }
327 }
328 }
329
330 c->end_processing ();
331
332 DEBUG_MSG_FUNC (SANITIZE, blob, sane ? "PASSED" : "FAILED");
333 if (sane)
334 return blob;
335 else {
336 hb_blob_destroy (blob);
337 return hb_blob_get_empty ();
338 }
339 }
340
341 static const Type* lock_instance (hb_blob_t *blob) {
342 hb_blob_make_immutable (blob);
343 const char *base = hb_blob_get_data (blob, NULL);
344 return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
345 }
346 };
347
348
349
350 /*
351 * Serialize
352 */
353
354 #ifndef HB_DEBUG_SERIALIZE
355 #define HB_DEBUG_SERIALIZE (HB_DEBUG+0)
356 #endif
357
358
359 #define TRACE_SERIALIZE(this) \
360 hb_auto_trace_t<HB_DEBUG_SERIALIZE, bool> trace \
361 (&c->debug_depth, "SERIALIZE", c, HB_FUNC, \
362 "");
363
364
365 struct hb_serialize_context_t
366 {
367 inline hb_serialize_context_t (void *start, unsigned int size)
368 {
369 this->start = (char *) start;
370 this->end = this->start + size;
371
372 this->ran_out_of_room = false;
373 this->head = this->start;
374 this->debug_depth = 0;
375 }
376
377 template <typename Type>
378 inline Type *start_serialize (void)
379 {
380 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, +1,
381 "start [%p..%p] (%lu bytes)",
382 this->start, this->end,
383 (unsigned long) (this->end - this->start));
384
385 return start_embed<Type> ();
386 }
387
388 inline void end_serialize (void)
389 {
390 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, -1,
391 "end [%p..%p] serialized %d bytes; %s",
392 this->start, this->end,
393 (int) (this->head - this->start),
394 this->ran_out_of_room ? "RAN OUT OF ROOM" : "did not ran out of room");
395
396 }
397
398 template <typename Type>
399 inline Type *copy (void)
400 {
401 assert (!this->ran_out_of_room);
402 unsigned int len = this->head - this->start;
403 void *p = malloc (len);
404 if (p)
405 memcpy (p, this->start, len);
406 return reinterpret_cast<Type *> (p);
407 }
408
409 template <typename Type>
410 inline Type *allocate_size (unsigned int size)
411 {
412 if (unlikely (this->ran_out_of_room || this->end - this->head < ptrdiff_t (size))) {
413 this->ran_out_of_room = true;
414 return NULL;
415 }
416 memset (this->head, 0, size);
417 char *ret = this->head;
418 this->head += size;
419 return reinterpret_cast<Type *> (ret);
420 }
421
422 template <typename Type>
423 inline Type *allocate_min (void)
424 {
425 return this->allocate_size<Type> (Type::min_size);
426 }
427
428 template <typename Type>
429 inline Type *start_embed (void)
430 {
431 Type *ret = reinterpret_cast<Type *> (this->head);
432 return ret;
433 }
434
435 template <typename Type>
436 inline Type *embed (const Type &obj)
437 {
438 unsigned int size = obj.get_size ();
439 Type *ret = this->allocate_size<Type> (size);
440 if (unlikely (!ret)) return NULL;
441 memcpy (ret, obj, size);
442 return ret;
443 }
444
445 template <typename Type>
446 inline Type *extend_min (Type &obj)
447 {
448 unsigned int size = obj.min_size;
449 assert (this->start <= (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
450 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
451 return reinterpret_cast<Type *> (&obj);
452 }
453
454 template <typename Type>
455 inline Type *extend (Type &obj)
456 {
457 unsigned int size = obj.get_size ();
458 assert (this->start < (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
459 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
460 return reinterpret_cast<Type *> (&obj);
461 }
462
463 inline void truncate (void *head)
464 {
465 assert (this->start < head && head <= this->head);
466 this->head = (char *) head;
467 }
468
469 unsigned int debug_depth;
470 char *start, *end, *head;
471 bool ran_out_of_room;
472 };
473
474 template <typename Type>
475 struct Supplier
476 {
477 inline Supplier (const Type *array, unsigned int len_)
478 {
479 head = array;
480 len = len_;
481 }
482 inline const Type operator [] (unsigned int i) const
483 {
484 if (unlikely (i >= len)) return Type ();
485 return head[i];
486 }
487
488 inline void advance (unsigned int count)
489 {
490 if (unlikely (count > len))
491 count = len;
492 len -= count;
493 head += count;
494 }
495
496 private:
497 inline Supplier (const Supplier<Type> &); /* Disallow copy */
498 inline Supplier<Type>& operator= (const Supplier<Type> &); /* Disallow copy */
499
500 unsigned int len;
501 const Type *head;
502 };
503
504
505
506
507 /*
508 *
509 * The OpenType Font File: Data Types
510 */
511
512
513 /* "The following data types are used in the OpenType font file.
514 * All OpenType fonts use Motorola-style byte ordering (Big Endian):" */
515
516 /*
517 * Int types
518 */
519
520
521 template <typename Type, int Bytes> struct BEInt;
522
523 template <typename Type>
524 struct BEInt<Type, 2>
525 {
526 public:
527 inline void set (Type i) { hb_be_uint16_put (v,i); }
528 inline operator Type (void) const { return hb_be_uint16_get (v); }
529 inline bool operator == (const BEInt<Type, 2>& o) const { return hb_be_uint16_eq (v, o.v); }
530 inline bool operator != (const BEInt<Type, 2>& o) const { return !(*this == o); }
531 private: uint8_t v[2];
532 };
533 template <typename Type>
534 struct BEInt<Type, 4>
535 {
536 public:
537 inline void set (Type i) { hb_be_uint32_put (v,i); }
538 inline operator Type (void) const { return hb_be_uint32_get (v); }
539 inline bool operator == (const BEInt<Type, 4>& o) const { return hb_be_uint32_eq (v, o.v); }
540 inline bool operator != (const BEInt<Type, 4>& o) const { return !(*this == o); }
541 private: uint8_t v[4];
542 };
543 template <typename Type>
544 struct BEInt<Type, 3>
545 {
546 public:
547 inline void set (Type i) { hb_be_uint24_put (v,i); }
548 inline operator Type (void) const { return hb_be_uint24_get (v); }
549 inline bool operator == (const BEInt<Type, 3>& o) const { return hb_be_uint24_eq (v, o.v); }
550 inline bool operator != (const BEInt<Type, 3>& o) const { return !(*this == o); }
551 private: uint8_t v[3];
552 };
553
554 /* Integer types in big-endian order and no alignment requirement */
555 template <typename Type, unsigned int Size>
556 struct IntType
557 {
558 inline void set (Type i) { v.set (i); }
559 inline operator Type(void) const { return v; }
560 inline bool operator == (const IntType<Type,Size> &o) const { return v == o.v; }
561 inline bool operator != (const IntType<Type,Size> &o) const { return v != o.v; }
562 static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }
563 inline int cmp (IntType<Type,Size> va) const { Type a = va; Type b = v; return a < b ? -1 : a == b ? 0 : +1; }
564 inline int cmp (Type a) const { Type b = v; return a < b ? -1 : a == b ? 0 : +1; }
565 inline bool sanitize (hb_sanitize_context_t *c) {
566 TRACE_SANITIZE (this);
567 return TRACE_RETURN (likely (c->check_struct (this)));
568 }
569 protected:
570 BEInt<Type, Size> v;
571 public:
572 DEFINE_SIZE_STATIC (Size);
573 };
574
575 typedef IntType<uint16_t, 2> USHORT; /* 16-bit unsigned integer. */
576 typedef IntType<int16_t, 2> SHORT; /* 16-bit signed integer. */
577 typedef IntType<uint32_t, 4> ULONG; /* 32-bit unsigned integer. */
578 typedef IntType<int32_t, 4> LONG; /* 32-bit signed integer. */
579 typedef IntType<uint32_t, 3> UINT24; /* 24-bit unsigned integer. */
580
581 /* 16-bit signed integer (SHORT) that describes a quantity in FUnits. */
582 typedef SHORT FWORD;
583
584 /* 16-bit unsigned integer (USHORT) that describes a quantity in FUnits. */
585 typedef USHORT UFWORD;
586
587 /* Date represented in number of seconds since 12:00 midnight, January 1,
588 * 1904. The value is represented as a signed 64-bit integer. */
589 struct LONGDATETIME
590 {
591 inline bool sanitize (hb_sanitize_context_t *c) {
592 TRACE_SANITIZE (this);
593 return TRACE_RETURN (likely (c->check_struct (this)));
594 }
595 protected:
596 LONG major;
597 ULONG minor;
598 public:
599 DEFINE_SIZE_STATIC (8);
600 };
601
602 /* Array of four uint8s (length = 32 bits) used to identify a script, language
603 * system, feature, or baseline */
604 struct Tag : ULONG
605 {
606 /* What the char* converters return is NOT nul-terminated. Print using "%.4s" */
607 inline operator const char* (void) const { return reinterpret_cast<const char *> (&this->v); }
608 inline operator char* (void) { return reinterpret_cast<char *> (&this->v); }
609 public:
610 DEFINE_SIZE_STATIC (4);
611 };
612 DEFINE_NULL_DATA (Tag, " ");
613
614 /* Glyph index number, same as uint16 (length = 16 bits) */
615 typedef USHORT GlyphID;
616
617 /* Script/language-system/feature index */
618 struct Index : USHORT {
619 static const unsigned int NOT_FOUND_INDEX = 0xFFFF;
620 };
621 DEFINE_NULL_DATA (Index, "\xff\xff");
622
623 /* Offset to a table, same as uint16 (length = 16 bits), Null offset = 0x0000 */
624 struct Offset : USHORT
625 {
626 inline bool is_null (void) const { return 0 == *this; }
627 public:
628 DEFINE_SIZE_STATIC (2);
629 };
630
631 /* LongOffset to a table, same as uint32 (length = 32 bits), Null offset = 0x00000000 */
632 struct LongOffset : ULONG
633 {
634 inline bool is_null (void) const { return 0 == *this; }
635 public:
636 DEFINE_SIZE_STATIC (4);
637 };
638
639
640 /* CheckSum */
641 struct CheckSum : ULONG
642 {
643 /* This is reference implementation from the spec. */
644 static inline uint32_t CalcTableChecksum (const ULONG *Table, uint32_t Length)
645 {
646 uint32_t Sum = 0L;
647 const ULONG *EndPtr = Table+((Length+3) & ~3) / ULONG::static_size;
648
649 while (Table < EndPtr)
650 Sum += *Table++;
651 return Sum;
652 }
653
654 /* Note: data should be 4byte aligned and have 4byte padding at the end. */
655 inline void set_for_data (const void *data, unsigned int length)
656 { set (CalcTableChecksum ((const ULONG *) data, length)); }
657
658 public:
659 DEFINE_SIZE_STATIC (4);
660 };
661
662
663 /*
664 * Version Numbers
665 */
666
667 struct FixedVersion
668 {
669 inline uint32_t to_int (void) const { return (major << 16) + minor; }
670
671 inline bool sanitize (hb_sanitize_context_t *c) {
672 TRACE_SANITIZE (this);
673 return TRACE_RETURN (c->check_struct (this));
674 }
675
676 USHORT major;
677 USHORT minor;
678 public:
679 DEFINE_SIZE_STATIC (4);
680 };
681
682
683
684 /*
685 * Template subclasses of Offset and LongOffset that do the dereferencing.
686 * Use: (base+offset)
687 */
688
689 template <typename OffsetType, typename Type>
690 struct GenericOffsetTo : OffsetType
691 {
692 inline const Type& operator () (const void *base) const
693 {
694 unsigned int offset = *this;
695 if (unlikely (!offset)) return Null(Type);
696 return StructAtOffset<Type> (base, offset);
697 }
698
699 inline Type& serialize (hb_serialize_context_t *c, void *base)
700 {
701 Type *t = c->start_embed<Type> ();
702 this->set ((char *) t - (char *) base); /* TODO(serialize) Overflow? */
703 return *t;
704 }
705
706 inline bool sanitize (hb_sanitize_context_t *c, void *base) {
707 TRACE_SANITIZE (this);
708 if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);
709 unsigned int offset = *this;
710 if (unlikely (!offset)) return TRACE_RETURN (true);
711 Type &obj = StructAtOffset<Type> (base, offset);
712 return TRACE_RETURN (likely (obj.sanitize (c)) || neuter (c));
713 }
714 template <typename T>
715 inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {
716 TRACE_SANITIZE (this);
717 if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);
718 unsigned int offset = *this;
719 if (unlikely (!offset)) return TRACE_RETURN (true);
720 Type &obj = StructAtOffset<Type> (base, offset);
721 return TRACE_RETURN (likely (obj.sanitize (c, user_data)) || neuter (c));
722 }
723
724 inline bool try_set (hb_sanitize_context_t *c, const OffsetType &v) {
725 if (c->may_edit (this, this->static_size)) {
726 this->set (v);
727 return true;
728 }
729 return false;
730 }
731 /* Set the offset to Null */
732 inline bool neuter (hb_sanitize_context_t *c) {
733 if (c->may_edit (this, this->static_size)) {
734 this->set (0); /* 0 is Null offset */
735 return true;
736 }
737 return false;
738 }
739 };
740 template <typename Base, typename OffsetType, typename Type>
741 inline const Type& operator + (const Base &base, const GenericOffsetTo<OffsetType, Type> &offset) { return offset (base); }
742 template <typename Base, typename OffsetType, typename Type>
743 inline Type& operator + (Base &base, GenericOffsetTo<OffsetType, Type> &offset) { return offset (base); }
744
745 template <typename Type>
746 struct OffsetTo : GenericOffsetTo<Offset, Type> {};
747
748 template <typename Type>
749 struct LongOffsetTo : GenericOffsetTo<LongOffset, Type> {};
750
751
752 /*
753 * Array Types
754 */
755
756 template <typename LenType, typename Type>
757 struct GenericArrayOf
758 {
759 const Type *sub_array (unsigned int start_offset, unsigned int *pcount /* IN/OUT */) const
760 {
761 unsigned int count = len;
762 if (unlikely (start_offset > count))
763 count = 0;
764 else
765 count -= start_offset;
766 count = MIN (count, *pcount);
767 *pcount = count;
768 return array + start_offset;
769 }
770
771 inline const Type& operator [] (unsigned int i) const
772 {
773 if (unlikely (i >= len)) return Null(Type);
774 return array[i];
775 }
776 inline Type& operator [] (unsigned int i)
777 {
778 return array[i];
779 }
780 inline unsigned int get_size (void) const
781 { return len.static_size + len * Type::static_size; }
782
783 inline bool serialize (hb_serialize_context_t *c,
784 unsigned int items_len)
785 {
786 TRACE_SERIALIZE (this);
787 if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
788 len.set (items_len); /* TODO(serialize) Overflow? */
789 if (unlikely (!c->extend (*this))) return TRACE_RETURN (false);
790 return TRACE_RETURN (true);
791 }
792
793 inline bool serialize (hb_serialize_context_t *c,
794 Supplier<Type> &items,
795 unsigned int items_len)
796 {
797 TRACE_SERIALIZE (this);
798 if (unlikely (!serialize (c, items_len))) return TRACE_RETURN (false);
799 for (unsigned int i = 0; i < items_len; i++)
800 array[i] = items[i];
801 items.advance (items_len);
802 return TRACE_RETURN (true);
803 }
804
805 inline bool sanitize (hb_sanitize_context_t *c) {
806 TRACE_SANITIZE (this);
807 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
808
809 /* Note: for structs that do not reference other structs,
810 * we do not need to call their sanitize() as we already did
811 * a bound check on the aggregate array size. We just include
812 * a small unreachable expression to make sure the structs
813 * pointed to do have a simple sanitize(), ie. they do not
814 * reference other structs via offsets.
815 */
816 (void) (false && array[0].sanitize (c));
817
818 return TRACE_RETURN (true);
819 }
820 inline bool sanitize (hb_sanitize_context_t *c, void *base) {
821 TRACE_SANITIZE (this);
822 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
823 unsigned int count = len;
824 for (unsigned int i = 0; i < count; i++)
825 if (unlikely (!array[i].sanitize (c, base)))
826 return TRACE_RETURN (false);
827 return TRACE_RETURN (true);
828 }
829 template <typename T>
830 inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {
831 TRACE_SANITIZE (this);
832 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
833 unsigned int count = len;
834 for (unsigned int i = 0; i < count; i++)
835 if (unlikely (!array[i].sanitize (c, base, user_data)))
836 return TRACE_RETURN (false);
837 return TRACE_RETURN (true);
838 }
839
840 private:
841 inline bool sanitize_shallow (hb_sanitize_context_t *c) {
842 TRACE_SANITIZE (this);
843 return TRACE_RETURN (c->check_struct (this) && c->check_array (this, Type::static_size, len));
844 }
845
846 public:
847 LenType len;
848 Type array[VAR];
849 public:
850 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
851 };
852
853 /* An array with a USHORT number of elements. */
854 template <typename Type>
855 struct ArrayOf : GenericArrayOf<USHORT, Type> {};
856
857 /* An array with a ULONG number of elements. */
858 template <typename Type>
859 struct LongArrayOf : GenericArrayOf<ULONG, Type> {};
860
861 /* Array of Offset's */
862 template <typename Type>
863 struct OffsetArrayOf : ArrayOf<OffsetTo<Type> > {};
864
865 /* Array of LongOffset's */
866 template <typename Type>
867 struct LongOffsetArrayOf : ArrayOf<LongOffsetTo<Type> > {};
868
869 /* LongArray of LongOffset's */
870 template <typename Type>
871 struct LongOffsetLongArrayOf : LongArrayOf<LongOffsetTo<Type> > {};
872
873 /* Array of offsets relative to the beginning of the array itself. */
874 template <typename Type>
875 struct OffsetListOf : OffsetArrayOf<Type>
876 {
877 inline const Type& operator [] (unsigned int i) const
878 {
879 if (unlikely (i >= this->len)) return Null(Type);
880 return this+this->array[i];
881 }
882
883 inline bool sanitize (hb_sanitize_context_t *c) {
884 TRACE_SANITIZE (this);
885 return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this));
886 }
887 template <typename T>
888 inline bool sanitize (hb_sanitize_context_t *c, T user_data) {
889 TRACE_SANITIZE (this);
890 return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this, user_data));
891 }
892 };
893
894
895 /* An array with a USHORT number of elements,
896 * starting at second element. */
897 template <typename Type>
898 struct HeadlessArrayOf
899 {
900 inline const Type& operator [] (unsigned int i) const
901 {
902 if (unlikely (i >= len || !i)) return Null(Type);
903 return array[i-1];
904 }
905 inline unsigned int get_size (void) const
906 { return len.static_size + (len ? len - 1 : 0) * Type::static_size; }
907
908 inline bool serialize (hb_serialize_context_t *c,
909 Supplier<Type> &items,
910 unsigned int items_len)
911 {
912 TRACE_SERIALIZE (this);
913 if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
914 len.set (items_len); /* TODO(serialize) Overflow? */
915 if (unlikely (!items_len)) return TRACE_RETURN (true);
916 if (unlikely (!c->extend (*this))) return TRACE_RETURN (false);
917 for (unsigned int i = 0; i < items_len - 1; i++)
918 array[i] = items[i];
919 items.advance (items_len - 1);
920 return TRACE_RETURN (true);
921 }
922
923 inline bool sanitize_shallow (hb_sanitize_context_t *c) {
924 return c->check_struct (this)
925 && c->check_array (this, Type::static_size, len);
926 }
927
928 inline bool sanitize (hb_sanitize_context_t *c) {
929 TRACE_SANITIZE (this);
930 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
931
932 /* Note: for structs that do not reference other structs,
933 * we do not need to call their sanitize() as we already did
934 * a bound check on the aggregate array size. We just include
935 * a small unreachable expression to make sure the structs
936 * pointed to do have a simple sanitize(), ie. they do not
937 * reference other structs via offsets.
938 */
939 (void) (false && array[0].sanitize (c));
940
941 return TRACE_RETURN (true);
942 }
943
944 USHORT len;
945 Type array[VAR];
946 public:
947 DEFINE_SIZE_ARRAY (sizeof (USHORT), array);
948 };
949
950
951 /* An array with sorted elements. Supports binary searching. */
952 template <typename Type>
953 struct SortedArrayOf : ArrayOf<Type> {
954
955 template <typename SearchType>
956 inline int search (const SearchType &x) const
957 {
958 /* Hand-coded bsearch here since this is in the hot inner loop. */
959 int min = 0, max = (int) this->len - 1;
960 while (min <= max)
961 {
962 int mid = (min + max) / 2;
963 int c = this->array[mid].cmp (x);
964 if (c < 0)
965 max = mid - 1;
966 else if (c > 0)
967 min = mid + 1;
968 else
969 return mid;
970 }
971 return -1;
972 }
973 };
974
975
976 } /* namespace OT */
977
978
979 #endif /* HB_OPEN_TYPE_PRIVATE_HH */

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