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 static inline const Type& CastR(const TObject &X)
46 { return reinterpret_cast<const Type&> (X); }
47 template<typename Type, typename TObject>
48 static 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 static inline const Type* CastP(const TObject *X)
54 { return reinterpret_cast<const Type*> (X); }
55 template<typename Type, typename TObject>
56 static 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 static 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 static 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 static inline const Type& StructAfter(const TObject &X)
72 { return StructAtOffset<Type>(&X, X.get_size()); }
73 template<typename Type, typename TObject>
74 static 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 inline unsigned int get_size (void) const { return (size); }
106
107 #define DEFINE_SIZE_UNION(size, _member) \
108 DEFINE_INSTANCE_ASSERTION (0*sizeof(this->u._member.static_size) + sizeof(this->u._member) == (size)); \
109 static const unsigned int min_size = (size)
110
111 #define DEFINE_SIZE_MIN(size) \
112 DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)); \
113 static const unsigned int min_size = (size)
114
115 #define DEFINE_SIZE_ARRAY(size, array) \
116 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \
117 DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \
118 static const unsigned int min_size = (size)
119
120 #define DEFINE_SIZE_ARRAY2(size, array1, array2) \
121 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \
122 DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \
123 static const unsigned int min_size = (size)
124
125
126
127 /*
128 * Null objects
129 */
130
131 /* Global nul-content Null pool. Enlarge as necessary. */
132 /* TODO This really should be a extern HB_INTERNAL and defined somewhere... */
133 static const void *_NullPool[(256+8) / sizeof (void *)];
134
135 /* Generic nul-content Null objects. */
136 template <typename Type>
137 static inline const Type& Null (void) {
138 ASSERT_STATIC (sizeof (Type) <= sizeof (_NullPool));
139 return *CastP<Type> (_NullPool);
140 }
141
142 /* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
143 #define DEFINE_NULL_DATA(Type, data) \
144 static const char _Null##Type[sizeof (Type) + 1] = data; /* +1 is for nul-termination in data */ \
145 template <> \
146 /*static*/ inline const Type& Null<Type> (void) { \
147 return *CastP<Type> (_Null##Type); \
148 } /* The following line really exists such that we end in a place needing semicolon */ \
149 ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))
150
151 /* Accessor macro. */
152 #define Null(Type) Null<Type>()
153
154
155 /*
156 * Dispatch
157 */
158
159 template <typename Context, typename Return, unsigned int MaxDebugDepth>
160 struct hb_dispatch_context_t
161 {
162 static const unsigned int max_debug_depth = MaxDebugDepth;
163 typedef Return return_t;
164 template <typename T, typename F>
165 inline bool may_dispatch (const T *obj, const F *format) { return true; }
166 static return_t no_dispatch_return_value (void) { return Context::default_return_value (); }
167 };
168
169
170 /*
171 * Sanitize
172 */
173
174 #ifndef HB_DEBUG_SANITIZE
175 #define HB_DEBUG_SANITIZE (HB_DEBUG+0)
176 #endif
177
178
179 #define TRACE_SANITIZE(this) \
180 hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace \
181 (&c->debug_depth, c->get_name (), this, HB_FUNC, \
182 "");
183
184 /* This limits sanitizing time on really broken fonts. */
185 #ifndef HB_SANITIZE_MAX_EDITS
186 #define HB_SANITIZE_MAX_EDITS 32
187 #endif
188
189 struct hb_sanitize_context_t :
190 hb_dispatch_context_t<hb_sanitize_context_t, bool, HB_DEBUG_SANITIZE>
191 {
192 inline hb_sanitize_context_t (void) :
193 debug_depth (0),
194 start (NULL), end (NULL),
195 writable (false), edit_count (0),
196 blob (NULL) {}
197
198 inline const char *get_name (void) { return "SANITIZE"; }
199 template <typename T, typename F>
200 inline bool may_dispatch (const T *obj, const F *format)
201 { return format->sanitize (this); }
202 template <typename T>
203 inline return_t dispatch (const T &obj) { return obj.sanitize (this); }
204 static return_t default_return_value (void) { return true; }
205 static return_t no_dispatch_return_value (void) { return false; }
206 bool stop_sublookup_iteration (const return_t r) const { return !r; }
207
208 inline void init (hb_blob_t *b)
209 {
210 this->blob = hb_blob_reference (b);
211 this->writable = false;
212 }
213
214 inline void start_processing (void)
215 {
216 this->start = hb_blob_get_data (this->blob, NULL);
217 this->end = this->start + hb_blob_get_length (this->blob);
218 assert (this->start <= this->end); /* Must not overflow. */
219 this->edit_count = 0;
220 this->debug_depth = 0;
221
222 DEBUG_MSG_LEVEL (SANITIZE, start, 0, +1,
223 "start [%p..%p] (%lu bytes)",
224 this->start, this->end,
225 (unsigned long) (this->end - this->start));
226 }
227
228 inline void end_processing (void)
229 {
230 DEBUG_MSG_LEVEL (SANITIZE, this->start, 0, -1,
231 "end [%p..%p] %u edit requests",
232 this->start, this->end, this->edit_count);
233
234 hb_blob_destroy (this->blob);
235 this->blob = NULL;
236 this->start = this->end = NULL;
237 }
238
239 inline bool check_range (const void *base, unsigned int len) const
240 {
241 const char *p = (const char *) base;
242 bool ok = this->start <= p && p <= this->end && (unsigned int) (this->end - p) >= len;
243
244 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
245 "check_range [%p..%p] (%d bytes) in [%p..%p] -> %s",
246 p, p + len, len,
247 this->start, this->end,
248 ok ? "OK" : "OUT-OF-RANGE");
249
250 return likely (ok);
251 }
252
253 inline bool check_array (const void *base, unsigned int record_size, unsigned int len) const
254 {
255 const char *p = (const char *) base;
256 bool overflows = _hb_unsigned_int_mul_overflows (len, record_size);
257 unsigned int array_size = record_size * len;
258 bool ok = !overflows && this->check_range (base, array_size);
259
260 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
261 "check_array [%p..%p] (%d*%d=%d bytes) in [%p..%p] -> %s",
262 p, p + (record_size * len), record_size, len, (unsigned int) array_size,
263 this->start, this->end,
264 overflows ? "OVERFLOWS" : ok ? "OK" : "OUT-OF-RANGE");
265
266 return likely (ok);
267 }
268
269 template <typename Type>
270 inline bool check_struct (const Type *obj) const
271 {
272 return likely (this->check_range (obj, obj->min_size));
273 }
274
275 inline bool may_edit (const void *base HB_UNUSED, unsigned int len HB_UNUSED)
276 {
277 if (this->edit_count >= HB_SANITIZE_MAX_EDITS)
278 return false;
279
280 const char *p = (const char *) base;
281 this->edit_count++;
282
283 DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
284 "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",
285 this->edit_count,
286 p, p + len, len,
287 this->start, this->end,
288 this->writable ? "GRANTED" : "DENIED");
289
290 return this->writable;
291 }
292
293 template <typename Type, typename ValueType>
294 inline bool try_set (const Type *obj, const ValueType &v) {
295 if (this->may_edit (obj, obj->static_size)) {
296 const_cast<Type *> (obj)->set (v);
297 return true;
298 }
299 return false;
300 }
301
302 mutable unsigned int debug_depth;
303 const char *start, *end;
304 bool writable;
305 unsigned int edit_count;
306 hb_blob_t *blob;
307 };
308
309
310
311 /* Template to sanitize an object. */
312 template <typename Type>
313 struct Sanitizer
314 {
315 static hb_blob_t *sanitize (hb_blob_t *blob) {
316 hb_sanitize_context_t c[1];
317 bool sane;
318
319 /* TODO is_sane() stuff */
320
321 c->init (blob);
322
323 retry:
324 DEBUG_MSG_FUNC (SANITIZE, c->start, "start");
325
326 c->start_processing ();
327
328 if (unlikely (!c->start)) {
329 c->end_processing ();
330 return blob;
331 }
332
333 Type *t = CastP<Type> (const_cast<char *> (c->start));
334
335 sane = t->sanitize (c);
336 if (sane) {
337 if (c->edit_count) {
338 DEBUG_MSG_FUNC (SANITIZE, c->start, "passed first round with %d edits; going for second round", c->edit_count);
339
340 /* sanitize again to ensure no toe-stepping */
341 c->edit_count = 0;
342 sane = t->sanitize (c);
343 if (c->edit_count) {
344 DEBUG_MSG_FUNC (SANITIZE, c->start, "requested %d edits in second round; FAILLING", c->edit_count);
345 sane = false;
346 }
347 }
348 } else {
349 unsigned int edit_count = c->edit_count;
350 if (edit_count && !c->writable) {
351 c->start = hb_blob_get_data_writable (blob, NULL);
352 c->end = c->start + hb_blob_get_length (blob);
353
354 if (c->start) {
355 c->writable = true;
356 /* ok, we made it writable by relocating. try again */
357 DEBUG_MSG_FUNC (SANITIZE, c->start, "retry");
358 goto retry;
359 }
360 }
361 }
362
363 c->end_processing ();
364
365 DEBUG_MSG_FUNC (SANITIZE, c->start, sane ? "PASSED" : "FAILED");
366 if (sane)
367 return blob;
368 else {
369 hb_blob_destroy (blob);
370 return hb_blob_get_empty ();
371 }
372 }
373
374 static const Type* lock_instance (hb_blob_t *blob) {
375 hb_blob_make_immutable (blob);
376 const char *base = hb_blob_get_data (blob, NULL);
377 return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
378 }
379 };
380
381
382
383 /*
384 * Serialize
385 */
386
387 #ifndef HB_DEBUG_SERIALIZE
388 #define HB_DEBUG_SERIALIZE (HB_DEBUG+0)
389 #endif
390
391
392 #define TRACE_SERIALIZE(this) \
393 hb_auto_trace_t<HB_DEBUG_SERIALIZE, bool> trace \
394 (&c->debug_depth, "SERIALIZE", c, HB_FUNC, \
395 "");
396
397
398 struct hb_serialize_context_t
399 {
400 inline hb_serialize_context_t (void *start_, unsigned int size)
401 {
402 this->start = (char *) start_;
403 this->end = this->start + size;
404
405 this->ran_out_of_room = false;
406 this->head = this->start;
407 this->debug_depth = 0;
408 }
409
410 template <typename Type>
411 inline Type *start_serialize (void)
412 {
413 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, +1,
414 "start [%p..%p] (%lu bytes)",
415 this->start, this->end,
416 (unsigned long) (this->end - this->start));
417
418 return start_embed<Type> ();
419 }
420
421 inline void end_serialize (void)
422 {
423 DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, -1,
424 "end [%p..%p] serialized %d bytes; %s",
425 this->start, this->end,
426 (int) (this->head - this->start),
427 this->ran_out_of_room ? "RAN OUT OF ROOM" : "did not ran out of room");
428
429 }
430
431 template <typename Type>
432 inline Type *copy (void)
433 {
434 assert (!this->ran_out_of_room);
435 unsigned int len = this->head - this->start;
436 void *p = malloc (len);
437 if (p)
438 memcpy (p, this->start, len);
439 return reinterpret_cast<Type *> (p);
440 }
441
442 template <typename Type>
443 inline Type *allocate_size (unsigned int size)
444 {
445 if (unlikely (this->ran_out_of_room || this->end - this->head < ptrdiff_t (size))) {
446 this->ran_out_of_room = true;
447 return NULL;
448 }
449 memset (this->head, 0, size);
450 char *ret = this->head;
451 this->head += size;
452 return reinterpret_cast<Type *> (ret);
453 }
454
455 template <typename Type>
456 inline Type *allocate_min (void)
457 {
458 return this->allocate_size<Type> (Type::min_size);
459 }
460
461 template <typename Type>
462 inline Type *start_embed (void)
463 {
464 Type *ret = reinterpret_cast<Type *> (this->head);
465 return ret;
466 }
467
468 template <typename Type>
469 inline Type *embed (const Type &obj)
470 {
471 unsigned int size = obj.get_size ();
472 Type *ret = this->allocate_size<Type> (size);
473 if (unlikely (!ret)) return NULL;
474 memcpy (ret, obj, size);
475 return ret;
476 }
477
478 template <typename Type>
479 inline Type *extend_min (Type &obj)
480 {
481 unsigned int size = obj.min_size;
482 assert (this->start <= (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
483 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
484 return reinterpret_cast<Type *> (&obj);
485 }
486
487 template <typename Type>
488 inline Type *extend (Type &obj)
489 {
490 unsigned int size = obj.get_size ();
491 assert (this->start < (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);
492 if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;
493 return reinterpret_cast<Type *> (&obj);
494 }
495
496 inline void truncate (void *new_head)
497 {
498 assert (this->start < new_head && new_head <= this->head);
499 this->head = (char *) new_head;
500 }
501
502 unsigned int debug_depth;
503 char *start, *end, *head;
504 bool ran_out_of_room;
505 };
506
507 template <typename Type>
508 struct Supplier
509 {
510 inline Supplier (const Type *array, unsigned int len_)
511 {
512 head = array;
513 len = len_;
514 }
515 inline const Type operator [] (unsigned int i) const
516 {
517 if (unlikely (i >= len)) return Type ();
518 return head[i];
519 }
520
521 inline void advance (unsigned int count)
522 {
523 if (unlikely (count > len))
524 count = len;
525 len -= count;
526 head += count;
527 }
528
529 private:
530 inline Supplier (const Supplier<Type> &); /* Disallow copy */
531 inline Supplier<Type>& operator= (const Supplier<Type> &); /* Disallow copy */
532
533 unsigned int len;
534 const Type *head;
535 };
536
537
538
539
540 /*
541 *
542 * The OpenType Font File: Data Types
543 */
544
545
546 /* "The following data types are used in the OpenType font file.
547 * All OpenType fonts use Motorola-style byte ordering (Big Endian):" */
548
549 /*
550 * Int types
551 */
552
553
554 template <typename Type, int Bytes> struct BEInt;
555
556 template <typename Type>
557 struct BEInt<Type, 1>
558 {
559 public:
560 inline void set (Type V)
561 {
562 v = V;
563 }
564 inline operator Type (void) const
565 {
566 return v;
567 }
568 private: uint8_t v;
569 };
570 template <typename Type>
571 struct BEInt<Type, 2>
572 {
573 public:
574 inline void set (Type V)
575 {
576 v[0] = (V >> 8) & 0xFF;
577 v[1] = (V ) & 0xFF;
578 }
579 inline operator Type (void) const
580 {
581 return (v[0] << 8)
582 + (v[1] );
583 }
584 private: uint8_t v[2];
585 };
586 template <typename Type>
587 struct BEInt<Type, 3>
588 {
589 public:
590 inline void set (Type V)
591 {
592 v[0] = (V >> 16) & 0xFF;
593 v[1] = (V >> 8) & 0xFF;
594 v[2] = (V ) & 0xFF;
595 }
596 inline operator Type (void) const
597 {
598 return (v[0] << 16)
599 + (v[1] << 8)
600 + (v[2] );
601 }
602 private: uint8_t v[3];
603 };
604 template <typename Type>
605 struct BEInt<Type, 4>
606 {
607 public:
608 inline void set (Type V)
609 {
610 v[0] = (V >> 24) & 0xFF;
611 v[1] = (V >> 16) & 0xFF;
612 v[2] = (V >> 8) & 0xFF;
613 v[3] = (V ) & 0xFF;
614 }
615 inline operator Type (void) const
616 {
617 return (v[0] << 24)
618 + (v[1] << 16)
619 + (v[2] << 8)
620 + (v[3] );
621 }
622 private: uint8_t v[4];
623 };
624
625 /* Integer types in big-endian order and no alignment requirement */
626 template <typename Type, unsigned int Size>
627 struct IntType
628 {
629 inline void set (Type i) { v.set (i); }
630 inline operator Type(void) const { return v; }
631 inline bool operator == (const IntType<Type,Size> &o) const { return (Type) v == (Type) o.v; }
632 inline bool operator != (const IntType<Type,Size> &o) const { return !(*this == o); }
633 static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }
634 inline int cmp (Type a) const
635 {
636 Type b = v;
637 if (sizeof (Type) < sizeof (int))
638 return (int) a - (int) b;
639 else
640 return a < b ? -1 : a == b ? 0 : +1;
641 }
642 inline bool sanitize (hb_sanitize_context_t *c) const
643 {
644 TRACE_SANITIZE (this);
645 return_trace (likely (c->check_struct (this)));
646 }
647 protected:
648 BEInt<Type, Size> v;
649 public:
650 DEFINE_SIZE_STATIC (Size);
651 };
652
653 typedef IntType<int8_t , 1> CHAR; /* 8-bit signed integer. */
654 typedef IntType<uint8_t , 1> BYTE; /* 8-bit unsigned integer. */
655 typedef IntType<int8_t , 1> INT8; /* 8-bit signed integer. */
656 typedef IntType<uint16_t, 2> USHORT; /* 16-bit unsigned integer. */
657 typedef IntType<int16_t, 2> SHORT; /* 16-bit signed integer. */
658 typedef IntType<uint32_t, 4> ULONG; /* 32-bit unsigned integer. */
659 typedef IntType<int32_t, 4> LONG; /* 32-bit signed integer. */
660 typedef IntType<uint32_t, 3> UINT24; /* 24-bit unsigned integer. */
661
662 /* 16-bit signed integer (SHORT) that describes a quantity in FUnits. */
663 typedef SHORT FWORD;
664
665 /* 16-bit unsigned integer (USHORT) that describes a quantity in FUnits. */
666 typedef USHORT UFWORD;
667
668 /* 16-bit signed fixed number with the low 14 bits of fraction (2.14). */
669 struct F2DOT14 : SHORT
670 {
671 //inline float to_float (void) const { return ???; }
672 //inline void set_float (float f) { v.set (f * ???); }
673 public:
674 DEFINE_SIZE_STATIC (2);
675 };
676
677 /* 32-bit signed fixed-point number (16.16). */
678 struct Fixed: LONG
679 {
680 //inline float to_float (void) const { return ???; }
681 //inline void set_float (float f) { v.set (f * ???); }
682 public:
683 DEFINE_SIZE_STATIC (4);
684 };
685
686 /* Date represented in number of seconds since 12:00 midnight, January 1,
687 * 1904. The value is represented as a signed 64-bit integer. */
688 struct LONGDATETIME
689 {
690 inline bool sanitize (hb_sanitize_context_t *c) const
691 {
692 TRACE_SANITIZE (this);
693 return_trace (likely (c->check_struct (this)));
694 }
695 protected:
696 LONG major;
697 ULONG minor;
698 public:
699 DEFINE_SIZE_STATIC (8);
700 };
701
702 /* Array of four uint8s (length = 32 bits) used to identify a script, language
703 * system, feature, or baseline */
704 struct Tag : ULONG
705 {
706 /* What the char* converters return is NOT nul-terminated. Print using "%.4s" */
707 inline operator const char* (void) const { return reinterpret_cast<const char *> (&this->v); }
708 inline operator char* (void) { return reinterpret_cast<char *> (&this->v); }
709 public:
710 DEFINE_SIZE_STATIC (4);
711 };
712 DEFINE_NULL_DATA (Tag, " ");
713
714 /* Glyph index number, same as uint16 (length = 16 bits) */
715 struct GlyphID : USHORT {
716 static inline int cmp (const GlyphID *a, const GlyphID *b) { return b->USHORT::cmp (*a); }
717 inline int cmp (hb_codepoint_t a) const { return (int) a - (int) *this; }
718 };
719
720 /* Script/language-system/feature index */
721 struct Index : USHORT {
722 static const unsigned int NOT_FOUND_INDEX = 0xFFFFu;
723 };
724 DEFINE_NULL_DATA (Index, "\xff\xff");
725
726 /* Offset, Null offset = 0 */
727 template <typename Type=USHORT>
728 struct Offset : Type
729 {
730 inline bool is_null (void) const { return 0 == *this; }
731 public:
732 DEFINE_SIZE_STATIC (sizeof(Type));
733 };
734
735
736 /* CheckSum */
737 struct CheckSum : ULONG
738 {
739 /* This is reference implementation from the spec. */
740 static inline uint32_t CalcTableChecksum (const ULONG *Table, uint32_t Length)
741 {
742 uint32_t Sum = 0L;
743 const ULONG *EndPtr = Table+((Length+3) & ~3) / ULONG::static_size;
744
745 while (Table < EndPtr)
746 Sum += *Table++;
747 return Sum;
748 }
749
750 /* Note: data should be 4byte aligned and have 4byte padding at the end. */
751 inline void set_for_data (const void *data, unsigned int length)
752 { set (CalcTableChecksum ((const ULONG *) data, length)); }
753
754 public:
755 DEFINE_SIZE_STATIC (4);
756 };
757
758
759 /*
760 * Version Numbers
761 */
762
763 template <typename FixedType=USHORT>
764 struct FixedVersion
765 {
766 inline uint32_t to_int (void) const { return (major << (sizeof(FixedType) * 8)) + minor; }
767
768 inline bool sanitize (hb_sanitize_context_t *c) const
769 {
770 TRACE_SANITIZE (this);
771 return_trace (c->check_struct (this));
772 }
773
774 FixedType major;
775 FixedType minor;
776 public:
777 DEFINE_SIZE_STATIC (2 * sizeof(FixedType));
778 };
779
780
781
782 /*
783 * Template subclasses of Offset that do the dereferencing.
784 * Use: (base+offset)
785 */
786
787 template <typename Type, typename OffsetType=USHORT>
788 struct OffsetTo : Offset<OffsetType>
789 {
790 inline const Type& operator () (const void *base) const
791 {
792 unsigned int offset = *this;
793 if (unlikely (!offset)) return Null(Type);
794 return StructAtOffset<Type> (base, offset);
795 }
796
797 inline Type& serialize (hb_serialize_context_t *c, const void *base)
798 {
799 Type *t = c->start_embed<Type> ();
800 this->set ((char *) t - (char *) base); /* TODO(serialize) Overflow? */
801 return *t;
802 }
803
804 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
805 {
806 TRACE_SANITIZE (this);
807 if (unlikely (!c->check_struct (this))) return_trace (false);
808 unsigned int offset = *this;
809 if (unlikely (!offset)) return_trace (true);
810 if (unlikely (!c->check_range (base, offset))) return_trace (false);
811 const Type &obj = StructAtOffset<Type> (base, offset);
812 return_trace (likely (obj.sanitize (c)) || neuter (c));
813 }
814 template <typename T>
815 inline bool sanitize (hb_sanitize_context_t *c, const void *base, T user_data) const
816 {
817 TRACE_SANITIZE (this);
818 if (unlikely (!c->check_struct (this))) return_trace (false);
819 unsigned int offset = *this;
820 if (unlikely (!offset)) return_trace (true);
821 if (unlikely (!c->check_range (base, offset))) return_trace (false);
822 const Type &obj = StructAtOffset<Type> (base, offset);
823 return_trace (likely (obj.sanitize (c, user_data)) || neuter (c));
824 }
825
826 /* Set the offset to Null */
827 inline bool neuter (hb_sanitize_context_t *c) const {
828 return c->try_set (this, 0);
829 }
830 DEFINE_SIZE_STATIC (sizeof(OffsetType));
831 };
832 template <typename Base, typename OffsetType, typename Type>
833 static inline const Type& operator + (const Base &base, const OffsetTo<Type, OffsetType> &offset) { return offset (base); }
834 template <typename Base, typename OffsetType, typename Type>
835 static inline Type& operator + (Base &base, OffsetTo<Type, OffsetType> &offset) { return offset (base); }
836
837
838 /*
839 * Array Types
840 */
841
842 /* An array with a number of elements. */
843 template <typename Type, typename LenType=USHORT>
844 struct ArrayOf
845 {
846 const Type *sub_array (unsigned int start_offset, unsigned int *pcount /* IN/OUT */) const
847 {
848 unsigned int count = len;
849 if (unlikely (start_offset > count))
850 count = 0;
851 else
852 count -= start_offset;
853 count = MIN (count, *pcount);
854 *pcount = count;
855 return array + start_offset;
856 }
857
858 inline const Type& operator [] (unsigned int i) const
859 {
860 if (unlikely (i >= len)) return Null(Type);
861 return array[i];
862 }
863 inline Type& operator [] (unsigned int i)
864 {
865 return array[i];
866 }
867 inline unsigned int get_size (void) const
868 { return len.static_size + len * Type::static_size; }
869
870 inline bool serialize (hb_serialize_context_t *c,
871 unsigned int items_len)
872 {
873 TRACE_SERIALIZE (this);
874 if (unlikely (!c->extend_min (*this))) return_trace (false);
875 len.set (items_len); /* TODO(serialize) Overflow? */
876 if (unlikely (!c->extend (*this))) return_trace (false);
877 return_trace (true);
878 }
879
880 inline bool serialize (hb_serialize_context_t *c,
881 Supplier<Type> &items,
882 unsigned int items_len)
883 {
884 TRACE_SERIALIZE (this);
885 if (unlikely (!serialize (c, items_len))) return_trace (false);
886 for (unsigned int i = 0; i < items_len; i++)
887 array[i] = items[i];
888 items.advance (items_len);
889 return_trace (true);
890 }
891
892 inline bool sanitize (hb_sanitize_context_t *c) const
893 {
894 TRACE_SANITIZE (this);
895 if (unlikely (!sanitize_shallow (c))) return_trace (false);
896
897 /* Note: for structs that do not reference other structs,
898 * we do not need to call their sanitize() as we already did
899 * a bound check on the aggregate array size. We just include
900 * a small unreachable expression to make sure the structs
901 * pointed to do have a simple sanitize(), ie. they do not
902 * reference other structs via offsets.
903 */
904 (void) (false && array[0].sanitize (c));
905
906 return_trace (true);
907 }
908 inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
909 {
910 TRACE_SANITIZE (this);
911 if (unlikely (!sanitize_shallow (c))) return_trace (false);
912 unsigned int count = len;
913 for (unsigned int i = 0; i < count; i++)
914 if (unlikely (!array[i].sanitize (c, base)))
915 return_trace (false);
916 return_trace (true);
917 }
918 template <typename T>
919 inline bool sanitize (hb_sanitize_context_t *c, const void *base, T user_data) const
920 {
921 TRACE_SANITIZE (this);
922 if (unlikely (!sanitize_shallow (c))) return_trace (false);
923 unsigned int count = len;
924 for (unsigned int i = 0; i < count; i++)
925 if (unlikely (!array[i].sanitize (c, base, user_data)))
926 return_trace (false);
927 return_trace (true);
928 }
929
930 template <typename SearchType>
931 inline int lsearch (const SearchType &x) const
932 {
933 unsigned int count = len;
934 for (unsigned int i = 0; i < count; i++)
935 if (!this->array[i].cmp (x))
936 return i;
937 return -1;
938 }
939
940 private:
941 inline bool sanitize_shallow (hb_sanitize_context_t *c) const
942 {
943 TRACE_SANITIZE (this);
944 return_trace (c->check_struct (this) && c->check_array (array, Type::static_size, len));
945 }
946
947 public:
948 LenType len;
949 Type array[VAR];
950 public:
951 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
952 };
953
954 /* Array of Offset's */
955 template <typename Type, typename OffsetType=USHORT>
956 struct OffsetArrayOf : ArrayOf<OffsetTo<Type, OffsetType> > {};
957
958 /* Array of offsets relative to the beginning of the array itself. */
959 template <typename Type>
960 struct OffsetListOf : OffsetArrayOf<Type>
961 {
962 inline const Type& operator [] (unsigned int i) const
963 {
964 if (unlikely (i >= this->len)) return Null(Type);
965 return this+this->array[i];
966 }
967
968 inline bool sanitize (hb_sanitize_context_t *c) const
969 {
970 TRACE_SANITIZE (this);
971 return_trace (OffsetArrayOf<Type>::sanitize (c, this));
972 }
973 template <typename T>
974 inline bool sanitize (hb_sanitize_context_t *c, T user_data) const
975 {
976 TRACE_SANITIZE (this);
977 return_trace (OffsetArrayOf<Type>::sanitize (c, this, user_data));
978 }
979 };
980
981
982 /* An array starting at second element. */
983 template <typename Type, typename LenType=USHORT>
984 struct HeadlessArrayOf
985 {
986 inline const Type& operator [] (unsigned int i) const
987 {
988 if (unlikely (i >= len || !i)) return Null(Type);
989 return array[i-1];
990 }
991 inline unsigned int get_size (void) const
992 { return len.static_size + (len ? len - 1 : 0) * Type::static_size; }
993
994 inline bool serialize (hb_serialize_context_t *c,
995 Supplier<Type> &items,
996 unsigned int items_len)
997 {
998 TRACE_SERIALIZE (this);
999 if (unlikely (!c->extend_min (*this))) return_trace (false);
1000 len.set (items_len); /* TODO(serialize) Overflow? */
1001 if (unlikely (!items_len)) return_trace (true);
1002 if (unlikely (!c->extend (*this))) return_trace (false);
1003 for (unsigned int i = 0; i < items_len - 1; i++)
1004 array[i] = items[i];
1005 items.advance (items_len - 1);
1006 return_trace (true);
1007 }
1008
1009 inline bool sanitize_shallow (hb_sanitize_context_t *c) const
1010 {
1011 return c->check_struct (this)
1012 && c->check_array (this, Type::static_size, len);
1013 }
1014
1015 inline bool sanitize (hb_sanitize_context_t *c) const
1016 {
1017 TRACE_SANITIZE (this);
1018 if (unlikely (!sanitize_shallow (c))) return_trace (false);
1019
1020 /* Note: for structs that do not reference other structs,
1021 * we do not need to call their sanitize() as we already did
1022 * a bound check on the aggregate array size. We just include
1023 * a small unreachable expression to make sure the structs
1024 * pointed to do have a simple sanitize(), ie. they do not
1025 * reference other structs via offsets.
1026 */
1027 (void) (false && array[0].sanitize (c));
1028
1029 return_trace (true);
1030 }
1031
1032 LenType len;
1033 Type array[VAR];
1034 public:
1035 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
1036 };
1037
1038
1039 /* An array with sorted elements. Supports binary searching. */
1040 template <typename Type, typename LenType=USHORT>
1041 struct SortedArrayOf : ArrayOf<Type, LenType>
1042 {
1043 template <typename SearchType>
1044 inline int bsearch (const SearchType &x) const
1045 {
1046 /* Hand-coded bsearch here since this is in the hot inner loop. */
1047 int min = 0, max = (int) this->len - 1;
1048 while (min <= max)
1049 {
1050 int mid = (min + max) / 2;
1051 int c = this->array[mid].cmp (x);
1052 if (c < 0)
1053 max = mid - 1;
1054 else if (c > 0)
1055 min = mid + 1;
1056 else
1057 return mid;
1058 }
1059 return -1;
1060 }
1061 };
1062
1063
1064 } /* namespace OT */
1065
1066
1067 #endif /* HB_OPEN_TYPE_PRIVATE_HH */