2 * Copyright © 2007,2008,2009,2010 Red Hat, Inc.
3 * Copyright © 2012 Google, Inc.
5 * This is part of HarfBuzz, a text shaping library.
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.
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
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.
25 * Red Hat Author(s): Behdad Esfahbod
26 * Google Author(s): Behdad Esfahbod
29 #ifndef HB_OPEN_TYPE_PRIVATE_HH
30 #define HB_OPEN_TYPE_PRIVATE_HH
32 #include "hb-private.hh"
42 /* Cast to struct T, reference to reference */
43 template<typename Type, typename TObject>
44 inline const Type& CastR(const TObject &X)
45 { return reinterpret_cast<const Type&> (X); }
46 template<typename Type, typename TObject>
47 inline Type& CastR(TObject &X)
48 { return reinterpret_cast<Type&> (X); }
50 /* Cast to struct T, pointer to pointer */
51 template<typename Type, typename TObject>
52 inline const Type* CastP(const TObject *X)
53 { return reinterpret_cast<const Type*> (X); }
54 template<typename Type, typename TObject>
55 inline Type* CastP(TObject *X)
56 { return reinterpret_cast<Type*> (X); }
58 /* StructAtOffset<T>(P,Ofs) returns the struct T& that is placed at memory
59 * location pointed to by P plus Ofs bytes. */
60 template<typename Type>
61 inline const Type& StructAtOffset(const void *P, unsigned int offset)
62 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }
63 template<typename Type>
64 inline Type& StructAtOffset(void *P, unsigned int offset)
65 { return * reinterpret_cast<Type*> ((char *) P + offset); }
67 /* StructAfter<T>(X) returns the struct T& that is placed after X.
68 * Works with X of variable size also. X must implement get_size() */
69 template<typename Type, typename TObject>
70 inline const Type& StructAfter(const TObject &X)
71 { return StructAtOffset<Type>(&X, X.get_size()); }
72 template<typename Type, typename TObject>
73 inline Type& StructAfter(TObject &X)
74 { return StructAtOffset<Type>(&X, X.get_size()); }
82 /* Check _assertion in a method environment */
83 #define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \
84 inline void _instance_assertion_on_line_##_line (void) const \
86 ASSERT_STATIC (_assertion); \
87 ASSERT_INSTANCE_POD (*this); /* Make sure it's POD. */ \
89 # define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)
90 # define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)
92 /* Check that _code compiles in a method environment */
93 #define _DEFINE_COMPILES_ASSERTION1(_line, _code) \
94 inline void _compiles_assertion_on_line_##_line (void) const \
96 # define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)
97 # define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)
100 #define DEFINE_SIZE_STATIC(size) \
101 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)); \
102 static const unsigned int static_size = (size); \
103 static const unsigned int min_size = (size)
105 /* Size signifying variable-sized array */
108 #define DEFINE_SIZE_UNION(size, _member) \
109 DEFINE_INSTANCE_ASSERTION (this->u._member.static_size == (size)); \
110 static const unsigned int min_size = (size)
112 #define DEFINE_SIZE_MIN(size) \
113 DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)); \
114 static const unsigned int min_size = (size)
116 #define DEFINE_SIZE_ARRAY(size, array) \
117 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \
118 DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \
119 static const unsigned int min_size = (size)
121 #define DEFINE_SIZE_ARRAY2(size, array1, array2) \
122 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \
123 DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \
124 static const unsigned int min_size = (size)
132 /* Global nul-content Null pool. Enlarge as necessary. */
133 /* TODO This really should be a extern HB_INTERNAL and defined somewhere... */
134 static const void *_NullPool[64 / sizeof (void *)];
136 /* Generic nul-content Null objects. */
137 template <typename Type>
138 static inline const Type& Null (void) {
139 ASSERT_STATIC (Type::min_size <= sizeof (_NullPool));
140 return *CastP<Type> (_NullPool);
143 /* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
144 #define DEFINE_NULL_DATA(Type, data) \
145 static const char _Null##Type[Type::min_size + 1] = data; /* +1 is for nul-termination in data */ \
147 inline const Type& Null<Type> (void) { \
148 return *CastP<Type> (_Null##Type); \
149 } /* The following line really exists such that we end in a place needing semicolon */ \
150 ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))
152 /* Accessor macro. */
153 #define Null(Type) Null<Type>()
161 #ifndef HB_DEBUG_SANITIZE
162 #define HB_DEBUG_SANITIZE (HB_DEBUG+0)
166 #define TRACE_SANITIZE() \
167 hb_auto_trace_t<HB_DEBUG_SANITIZE> trace (&c->debug_depth, "SANITIZE", this, HB_FUNC, "");
170 struct hb_sanitize_context_t
172 inline void init (hb_blob_t *b)
174 this->blob = hb_blob_reference (b);
175 this->writable = false;
178 inline void start_processing (void)
180 this->start = hb_blob_get_data (this->blob, NULL);
181 this->end = this->start + hb_blob_get_length (this->blob);
182 this->edit_count = 0;
183 this->debug_depth = 0;
185 DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, +1,
186 "start [%p..%p] (%lu bytes)",
187 this->start, this->end,
188 (unsigned long) (this->end - this->start));
191 inline void end_processing (void)
193 DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, -1,
194 "end [%p..%p] %u edit requests",
195 this->start, this->end, this->edit_count);
197 hb_blob_destroy (this->blob);
199 this->start = this->end = NULL;
202 inline bool check_range (const void *base, unsigned int len) const
204 const char *p = (const char *) base;
206 hb_auto_trace_t<HB_DEBUG_SANITIZE> trace (&this->debug_depth, "SANITIZE", this->blob, NULL,
207 "check_range [%p..%p] (%d bytes) in [%p..%p]",
209 this->start, this->end);
211 return TRACE_RETURN (likely (this->start <= p && p <= this->end && (unsigned int) (this->end - p) >= len));
214 inline bool check_array (const void *base, unsigned int record_size, unsigned int len) const
216 const char *p = (const char *) base;
217 bool overflows = _hb_unsigned_int_mul_overflows (len, record_size);
219 hb_auto_trace_t<HB_DEBUG_SANITIZE> trace (&this->debug_depth, "SANITIZE", this->blob, NULL,
220 "check_array [%p..%p] (%d*%d=%ld bytes) in [%p..%p]",
221 p, p + (record_size * len), record_size, len, (unsigned long) record_size * len,
222 this->start, this->end);
224 return TRACE_RETURN (likely (!overflows && this->check_range (base, record_size * len)));
227 template <typename Type>
228 inline bool check_struct (const Type *obj) const
230 return likely (this->check_range (obj, obj->min_size));
233 inline bool may_edit (const void *base HB_UNUSED, unsigned int len HB_UNUSED)
235 const char *p = (const char *) base;
238 hb_auto_trace_t<HB_DEBUG_SANITIZE> trace (&this->debug_depth, "SANITIZE", this->blob, NULL,
239 "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",
242 this->start, this->end);
244 return TRACE_RETURN (this->writable);
247 mutable unsigned int debug_depth;
248 const char *start, *end;
250 unsigned int edit_count;
256 /* Template to sanitize an object. */
257 template <typename Type>
260 static hb_blob_t *sanitize (hb_blob_t *blob) {
261 hb_sanitize_context_t c[1] = {{0}};
264 /* TODO is_sane() stuff */
269 DEBUG_MSG_FUNC (SANITIZE, blob, "start");
271 c->start_processing ();
273 if (unlikely (!c->start)) {
274 c->end_processing ();
278 Type *t = CastP<Type> (const_cast<char *> (c->start));
280 sane = t->sanitize (c);
283 DEBUG_MSG_FUNC (SANITIZE, blob, "passed first round with %d edits; going for second round", c->edit_count);
285 /* sanitize again to ensure no toe-stepping */
287 sane = t->sanitize (c);
289 DEBUG_MSG_FUNC (SANITIZE, blob, "requested %d edits in second round; FAILLING", c->edit_count);
294 unsigned int edit_count = c->edit_count;
295 if (edit_count && !c->writable) {
296 c->start = hb_blob_get_data_writable (blob, NULL);
297 c->end = c->start + hb_blob_get_length (blob);
301 /* ok, we made it writable by relocating. try again */
302 DEBUG_MSG_FUNC (SANITIZE, blob, "retry");
308 c->end_processing ();
310 DEBUG_MSG_FUNC (SANITIZE, blob, sane ? "PASSED" : "FAILED");
314 hb_blob_destroy (blob);
315 return hb_blob_get_empty ();
319 static const Type* lock_instance (hb_blob_t *blob) {
320 hb_blob_make_immutable (blob);
321 const char *base = hb_blob_get_data (blob, NULL);
322 return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
331 * The OpenType Font File: Data Types
335 /* "The following data types are used in the OpenType font file.
336 * All OpenType fonts use Motorola-style byte ordering (Big Endian):" */
343 template <typename Type, int Bytes> struct BEInt;
345 template <typename Type>
346 struct BEInt<Type, 2>
349 inline void set (Type i) { hb_be_uint16_put (v,i); }
350 inline operator Type (void) const { return hb_be_uint16_get (v); }
351 inline bool operator == (const BEInt<Type, 2>& o) const { return hb_be_uint16_eq (v, o.v); }
352 inline bool operator != (const BEInt<Type, 2>& o) const { return !(*this == o); }
353 private: uint8_t v[2];
355 template <typename Type>
356 struct BEInt<Type, 4>
359 inline void set (Type i) { hb_be_uint32_put (v,i); }
360 inline operator Type (void) const { return hb_be_uint32_get (v); }
361 inline bool operator == (const BEInt<Type, 4>& o) const { return hb_be_uint32_eq (v, o.v); }
362 inline bool operator != (const BEInt<Type, 4>& o) const { return !(*this == o); }
363 private: uint8_t v[4];
366 /* Integer types in big-endian order and no alignment requirement */
367 template <typename Type>
370 inline void set (Type i) { v.set (i); }
371 inline operator Type(void) const { return v; }
372 inline bool operator == (const IntType<Type> &o) const { return v == o.v; }
373 inline bool operator != (const IntType<Type> &o) const { return v != o.v; }
374 inline int cmp (Type a) const { Type b = v; return a < b ? -1 : a == b ? 0 : +1; }
375 inline bool sanitize (hb_sanitize_context_t *c) {
377 return TRACE_RETURN (likely (c->check_struct (this)));
380 BEInt<Type, sizeof (Type)> v;
382 DEFINE_SIZE_STATIC (sizeof (Type));
385 /* Typedef these to avoid clash with windows.h */
386 #define USHORT HB_USHORT
387 #define SHORT HB_SHORT
388 #define ULONG HB_ULONG
390 typedef IntType<uint16_t> USHORT; /* 16-bit unsigned integer. */
391 typedef IntType<int16_t> SHORT; /* 16-bit signed integer. */
392 typedef IntType<uint32_t> ULONG; /* 32-bit unsigned integer. */
393 typedef IntType<int32_t> LONG; /* 32-bit signed integer. */
395 /* 16-bit signed integer (SHORT) that describes a quantity in FUnits. */
398 /* 16-bit unsigned integer (USHORT) that describes a quantity in FUnits. */
399 typedef USHORT UFWORD;
401 /* Date represented in number of seconds since 12:00 midnight, January 1,
402 * 1904. The value is represented as a signed 64-bit integer. */
405 inline bool sanitize (hb_sanitize_context_t *c) {
407 return TRACE_RETURN (likely (c->check_struct (this)));
413 DEFINE_SIZE_STATIC (8);
416 /* Array of four uint8s (length = 32 bits) used to identify a script, language
417 * system, feature, or baseline */
420 /* What the char* converters return is NOT nul-terminated. Print using "%.4s" */
421 inline operator const char* (void) const { return reinterpret_cast<const char *> (&this->v); }
422 inline operator char* (void) { return reinterpret_cast<char *> (&this->v); }
424 DEFINE_SIZE_STATIC (4);
426 DEFINE_NULL_DATA (Tag, " ");
428 /* Glyph index number, same as uint16 (length = 16 bits) */
429 typedef USHORT GlyphID;
431 /* Script/language-system/feature index */
432 struct Index : USHORT {
433 static const unsigned int NOT_FOUND_INDEX = 0xFFFF;
435 DEFINE_NULL_DATA (Index, "\xff\xff");
437 /* Offset to a table, same as uint16 (length = 16 bits), Null offset = 0x0000 */
438 typedef USHORT Offset;
440 /* LongOffset to a table, same as uint32 (length = 32 bits), Null offset = 0x00000000 */
441 typedef ULONG LongOffset;
445 struct CheckSum : ULONG
447 static uint32_t CalcTableChecksum (ULONG *Table, uint32_t Length)
450 ULONG *EndPtr = Table+((Length+3) & ~3) / ULONG::static_size;
452 while (Table < EndPtr)
457 DEFINE_SIZE_STATIC (4);
467 inline uint32_t to_int (void) const { return (major << 16) + minor; }
469 inline bool sanitize (hb_sanitize_context_t *c) {
471 return TRACE_RETURN (c->check_struct (this));
477 DEFINE_SIZE_STATIC (4);
483 * Template subclasses of Offset and LongOffset that do the dereferencing.
487 template <typename OffsetType, typename Type>
488 struct GenericOffsetTo : OffsetType
490 inline const Type& operator () (const void *base) const
492 unsigned int offset = *this;
493 if (unlikely (!offset)) return Null(Type);
494 return StructAtOffset<Type> (base, offset);
497 inline bool sanitize (hb_sanitize_context_t *c, void *base) {
499 if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);
500 unsigned int offset = *this;
501 if (unlikely (!offset)) return TRACE_RETURN (true);
502 Type &obj = StructAtOffset<Type> (base, offset);
503 return TRACE_RETURN (likely (obj.sanitize (c)) || neuter (c));
505 template <typename T>
506 inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {
508 if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);
509 unsigned int offset = *this;
510 if (unlikely (!offset)) return TRACE_RETURN (true);
511 Type &obj = StructAtOffset<Type> (base, offset);
512 return TRACE_RETURN (likely (obj.sanitize (c, user_data)) || neuter (c));
516 /* Set the offset to Null */
517 inline bool neuter (hb_sanitize_context_t *c) {
518 if (c->may_edit (this, this->static_size)) {
519 this->set (0); /* 0 is Null offset */
525 template <typename Base, typename OffsetType, typename Type>
526 inline const Type& operator + (const Base &base, GenericOffsetTo<OffsetType, Type> offset) { return offset (base); }
528 template <typename Type>
529 struct OffsetTo : GenericOffsetTo<Offset, Type> {};
531 template <typename Type>
532 struct LongOffsetTo : GenericOffsetTo<LongOffset, Type> {};
539 template <typename LenType, typename Type>
540 struct GenericArrayOf
542 const Type *sub_array (unsigned int start_offset, unsigned int *pcount /* IN/OUT */) const
544 unsigned int count = len;
545 if (unlikely (start_offset > count))
548 count -= start_offset;
549 count = MIN (count, *pcount);
551 return array + start_offset;
554 inline const Type& operator [] (unsigned int i) const
556 if (unlikely (i >= len)) return Null(Type);
559 inline unsigned int get_size (void) const
560 { return len.static_size + len * Type::static_size; }
562 inline bool sanitize (hb_sanitize_context_t *c) {
564 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
566 /* Note: for structs that do not reference other structs,
567 * we do not need to call their sanitize() as we already did
568 * a bound check on the aggregate array size. We just include
569 * a small unreachable expression to make sure the structs
570 * pointed to do have a simple sanitize(), ie. they do not
571 * reference other structs via offsets.
573 (void) (false && array[0].sanitize (c));
575 return TRACE_RETURN (true);
577 inline bool sanitize (hb_sanitize_context_t *c, void *base) {
579 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
580 unsigned int count = len;
581 for (unsigned int i = 0; i < count; i++)
582 if (unlikely (!array[i].sanitize (c, base)))
583 return TRACE_RETURN (false);
584 return TRACE_RETURN (true);
586 template <typename T>
587 inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {
589 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
590 unsigned int count = len;
591 for (unsigned int i = 0; i < count; i++)
592 if (unlikely (!array[i].sanitize (c, base, user_data)))
593 return TRACE_RETURN (false);
594 return TRACE_RETURN (true);
598 inline bool sanitize_shallow (hb_sanitize_context_t *c) {
600 return TRACE_RETURN (c->check_struct (this) && c->check_array (this, Type::static_size, len));
607 DEFINE_SIZE_ARRAY (sizeof (LenType), array);
610 /* An array with a USHORT number of elements. */
611 template <typename Type>
612 struct ArrayOf : GenericArrayOf<USHORT, Type> {};
614 /* An array with a ULONG number of elements. */
615 template <typename Type>
616 struct LongArrayOf : GenericArrayOf<ULONG, Type> {};
618 /* Array of Offset's */
619 template <typename Type>
620 struct OffsetArrayOf : ArrayOf<OffsetTo<Type> > {};
622 /* Array of LongOffset's */
623 template <typename Type>
624 struct LongOffsetArrayOf : ArrayOf<LongOffsetTo<Type> > {};
626 /* LongArray of LongOffset's */
627 template <typename Type>
628 struct LongOffsetLongArrayOf : LongArrayOf<LongOffsetTo<Type> > {};
630 /* Array of offsets relative to the beginning of the array itself. */
631 template <typename Type>
632 struct OffsetListOf : OffsetArrayOf<Type>
634 inline const Type& operator [] (unsigned int i) const
636 if (unlikely (i >= this->len)) return Null(Type);
637 return this+this->array[i];
640 inline bool sanitize (hb_sanitize_context_t *c) {
642 return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this));
644 template <typename T>
645 inline bool sanitize (hb_sanitize_context_t *c, T user_data) {
647 return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this, user_data));
652 /* An array with a USHORT number of elements,
653 * starting at second element. */
654 template <typename Type>
655 struct HeadlessArrayOf
657 inline const Type& operator [] (unsigned int i) const
659 if (unlikely (i >= len || !i)) return Null(Type);
662 inline unsigned int get_size (void) const
663 { return len.static_size + (len ? len - 1 : 0) * Type::static_size; }
665 inline bool sanitize_shallow (hb_sanitize_context_t *c) {
666 return c->check_struct (this)
667 && c->check_array (this, Type::static_size, len);
670 inline bool sanitize (hb_sanitize_context_t *c) {
672 if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);
674 /* Note: for structs that do not reference other structs,
675 * we do not need to call their sanitize() as we already did
676 * a bound check on the aggregate array size. We just include
677 * a small unreachable expression to make sure the structs
678 * pointed to do have a simple sanitize(), ie. they do not
679 * reference other structs via offsets.
681 (void) (false && array[0].sanitize (c));
683 return TRACE_RETURN (true);
689 DEFINE_SIZE_ARRAY (sizeof (USHORT), array);
693 /* An array with sorted elements. Supports binary searching. */
694 template <typename Type>
695 struct SortedArrayOf : ArrayOf<Type> {
697 template <typename SearchType>
698 inline int search (const SearchType &x) const {
699 unsigned int count = this->len;
700 /* Linear search is *much* faster for small counts. */
701 if (likely (count < 32)) {
702 for (unsigned int i = 0; i < count; i++)
703 if (this->array[i].cmp (x) == 0)
708 static int cmp (const SearchType *a, const Type *b) { return b->cmp (*a); }
710 const Type *p = (const Type *) bsearch (&x, this->array, this->len, sizeof (this->array[0]), (hb_compare_func_t) Cmp::cmp);
711 return p ? p - this->array : -1;
718 #endif /* HB_OPEN_TYPE_PRIVATE_HH */