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 /*

  * Copyright © 2007,2008,2009,2010  Red Hat, Inc.

  * Copyright © 2012  Google, Inc.

  *

  *  This is part of HarfBuzz, a text shaping library.

  *

  * Permission is hereby granted, without written agreement and without

  * license or royalty fees, to use, copy, modify, and distribute this

  * software and its documentation for any purpose, provided that the

  * above copyright notice and the following two paragraphs appear in

  * all copies of this software.

  *

  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

  * DAMAGE.

  *

  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

  *

  * Red Hat Author(s): Behdad Esfahbod

  * Google Author(s): Behdad Esfahbod

  */

 #ifndef HB_OPEN_TYPE_PRIVATE_HH

 #define HB_OPEN_TYPE_PRIVATE_HH

 #include "hb-private.hh"

 namespace OT {

 /*

  * Casts

  */

 /* Cast to struct T, reference to reference */

 template<typename Type, typename TObject>

 inline const Type& CastR(const TObject &X)

 { return reinterpret_cast<const Type&> (X); }

 template<typename Type, typename TObject>

 inline Type& CastR(TObject &X)

 { return reinterpret_cast<Type&> (X); }

 /* Cast to struct T, pointer to pointer */

 template<typename Type, typename TObject>

 inline const Type* CastP(const TObject *X)

 { return reinterpret_cast<const Type*> (X); }

 template<typename Type, typename TObject>

 inline Type* CastP(TObject *X)

 { return reinterpret_cast<Type*> (X); }

 /* StructAtOffset<T>(P,Ofs) returns the struct T& that is placed at memory

  * location pointed to by P plus Ofs bytes. */

 template<typename Type>

 inline const Type& StructAtOffset(const void *P, unsigned int offset)

 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }

 template<typename Type>

 inline Type& StructAtOffset(void *P, unsigned int offset)

 { return * reinterpret_cast<Type*> ((char *) P + offset); }

 /* StructAfter<T>(X) returns the struct T& that is placed after X.

  * Works with X of variable size also.  X must implement get_size() */

 template<typename Type, typename TObject>

 inline const Type& StructAfter(const TObject &X)

 { return StructAtOffset<Type>(&X, X.get_size()); }

 template<typename Type, typename TObject>

 inline Type& StructAfter(TObject &X)

 { return StructAtOffset<Type>(&X, X.get_size()); }

 /*

  * Size checking

  */

 /* Check _assertion in a method environment */

 #define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \

   inline void _instance_assertion_on_line_##_line (void) const \

   { \

     ASSERT_STATIC (_assertion); \

     ASSERT_INSTANCE_POD (*this); /* Make sure it's POD. */ \

   }

 # define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)

 # define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)

 /* Check that _code compiles in a method environment */

 #define _DEFINE_COMPILES_ASSERTION1(_line, _code) \

   inline void _compiles_assertion_on_line_##_line (void) const \

   { _code; }

 # define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)

 # define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)

 #define DEFINE_SIZE_STATIC(size) \

   DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)); \

   static const unsigned int static_size = (size); \

   static const unsigned int min_size = (size)

 /* Size signifying variable-sized array */

 #define VAR 1

 #define DEFINE_SIZE_UNION(size, _member) \

   DEFINE_INSTANCE_ASSERTION (this->u._member.static_size == (size)); \

   static const unsigned int min_size = (size)

 #define DEFINE_SIZE_MIN(size) \

   DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)); \

   static const unsigned int min_size = (size)

 #define DEFINE_SIZE_ARRAY(size, array) \

   DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \

   DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \

   static const unsigned int min_size = (size)

 #define DEFINE_SIZE_ARRAY2(size, array1, array2) \

   DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \

   DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \

   static const unsigned int min_size = (size)

 /*

  * Null objects

  */

 /* Global nul-content Null pool.  Enlarge as necessary. */

 /* TODO This really should be a extern HB_INTERNAL and defined somewhere... */

 static const void *_NullPool[64 / sizeof (void *)];

 /* Generic nul-content Null objects. */

 template <typename Type>

 static inline const Type& Null (void) {

   ASSERT_STATIC (sizeof (Type) <= sizeof (_NullPool));

   return *CastP<Type> (_NullPool);

 }

 /* Specializaiton for arbitrary-content arbitrary-sized Null objects. */

 #define DEFINE_NULL_DATA(Type, data) \

 static const char _Null##Type[sizeof (Type) + 1] = data; /* +1 is for nul-termination in data */ \

 template <> \

 inline const Type& Null<Type> (void) { \

   return *CastP<Type> (_Null##Type); \

 } /* The following line really exists such that we end in a place needing semicolon */ \

 ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))

 /* Accessor macro. */

 #define Null(Type) Null<Type>()

 /*

  * Sanitize

  */

 #ifndef HB_DEBUG_SANITIZE

 #define HB_DEBUG_SANITIZE (HB_DEBUG+0)

 #endif

 #define TRACE_SANITIZE(this) \

 	hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "");

 /* This limits sanitizing time on really broken fonts. */

 #ifndef HB_SANITIZE_MAX_EDITS

 #define HB_SANITIZE_MAX_EDITS 100

 #endif

 struct hb_sanitize_context_t

 {

   inline const char *get_name (void) { return "SANITIZE"; }

   static const unsigned int max_debug_depth = HB_DEBUG_SANITIZE;

   typedef bool return_t;

   template <typename T>

   inline return_t dispatch (const T &obj) { return obj.sanitize (this); }

   static return_t default_return_value (void) { return true; }

   bool stop_sublookup_iteration (const return_t r HB_UNUSED) const { return false; }

   inline void init (hb_blob_t *b)

   {

     this->blob = hb_blob_reference (b);

     this->writable = false;

   }

   inline void start_processing (void)

   {

     this->start = hb_blob_get_data (this->blob, NULL);

     this->end = this->start + hb_blob_get_length (this->blob);

     this->edit_count = 0;

     this->debug_depth = 0;

     DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, +1,

 		     "start [%p..%p] (%lu bytes)",

 		     this->start, this->end,

 		     (unsigned long) (this->end - this->start));

   }

   inline void end_processing (void)

   {

     DEBUG_MSG_LEVEL (SANITIZE, this->blob, 0, -1,

 		     "end [%p..%p] %u edit requests",

 		     this->start, this->end, this->edit_count);

     hb_blob_destroy (this->blob);

     this->blob = NULL;

     this->start = this->end = NULL;

   }

   inline bool check_range (const void *base, unsigned int len) const

   {

     const char *p = (const char *) base;

     hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace

       (&this->debug_depth, "SANITIZE", this->blob, NULL,

        "check_range [%p..%p] (%d bytes) in [%p..%p]",

        p, p + len, len,

        this->start, this->end);

     return TRACE_RETURN (likely (this->start <= p && p <= this->end && (unsigned int) (this->end - p) >= len));

   }

   inline bool check_array (const void *base, unsigned int record_size, unsigned int len) const

   {

     const char *p = (const char *) base;

     bool overflows = _hb_unsigned_int_mul_overflows (len, record_size);

     hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace

       (&this->debug_depth, "SANITIZE", this->blob, NULL,

        "check_array [%p..%p] (%d*%d=%ld bytes) in [%p..%p]",

        p, p + (record_size * len), record_size, len, (unsigned long) record_size * len,

        this->start, this->end);

     return TRACE_RETURN (likely (!overflows && this->check_range (base, record_size * len)));

   }

   template <typename Type>

   inline bool check_struct (const Type *obj) const

   {

     return likely (this->check_range (obj, obj->min_size));

   }

   inline bool may_edit (const void *base HB_UNUSED, unsigned int len HB_UNUSED)

   {

     if (this->edit_count >= HB_SANITIZE_MAX_EDITS)

       return false;

     const char *p = (const char *) base;

     this->edit_count++;

     hb_auto_trace_t<HB_DEBUG_SANITIZE, bool> trace

       (&this->debug_depth, "SANITIZE", this->blob, NULL,

        "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",

        this->edit_count,

        p, p + len, len,

        this->start, this->end,

        this->writable ? "GRANTED" : "DENIED");

     return TRACE_RETURN (this->writable);

   }

   mutable unsigned int debug_depth;

   const char *start, *end;

   bool writable;

   unsigned int edit_count;

   hb_blob_t *blob;

 };

 /* Template to sanitize an object. */

 template <typename Type>

 struct Sanitizer

 {

   static hb_blob_t *sanitize (hb_blob_t *blob) {

     hb_sanitize_context_t c[1] = {{0}};

     bool sane;

     /* TODO is_sane() stuff */

     c->init (blob);

   retry:

     DEBUG_MSG_FUNC (SANITIZE, blob, "start");

     c->start_processing ();

     if (unlikely (!c->start)) {

       c->end_processing ();

       return blob;

     }

     Type *t = CastP<Type> (const_cast<char *> (c->start));

     sane = t->sanitize (c);

     if (sane) {

       if (c->edit_count) {

 	DEBUG_MSG_FUNC (SANITIZE, blob, "passed first round with %d edits; going for second round", c->edit_count);

         /* sanitize again to ensure no toe-stepping */

         c->edit_count = 0;

 	sane = t->sanitize (c);

 	if (c->edit_count) {

 	  DEBUG_MSG_FUNC (SANITIZE, blob, "requested %d edits in second round; FAILLING", c->edit_count);

 	  sane = false;

 	}

       }

     } else {

       unsigned int edit_count = c->edit_count;

       if (edit_count && !c->writable) {

         c->start = hb_blob_get_data_writable (blob, NULL);

 	c->end = c->start + hb_blob_get_length (blob);

 	if (c->start) {

 	  c->writable = true;

 	  /* ok, we made it writable by relocating.  try again */

 	  DEBUG_MSG_FUNC (SANITIZE, blob, "retry");

 	  goto retry;

 	}

       }

     }

     c->end_processing ();

     DEBUG_MSG_FUNC (SANITIZE, blob, sane ? "PASSED" : "FAILED");

     if (sane)

       return blob;

     else {

       hb_blob_destroy (blob);

       return hb_blob_get_empty ();

     }

   }

   static const Type* lock_instance (hb_blob_t *blob) {

     hb_blob_make_immutable (blob);

     const char *base = hb_blob_get_data (blob, NULL);

     return unlikely (!base) ? &Null(Type) : CastP<Type> (base);

   }

 };

 /*

  * Serialize

  */

 #ifndef HB_DEBUG_SERIALIZE

 #define HB_DEBUG_SERIALIZE (HB_DEBUG+0)

 #endif

 #define TRACE_SERIALIZE(this) \

 	hb_auto_trace_t<HB_DEBUG_SERIALIZE, bool> trace \

 	(&c->debug_depth, "SERIALIZE", c, HB_FUNC, \

 	 "");

 struct hb_serialize_context_t

 {

   inline hb_serialize_context_t (void *start, unsigned int size)

   {

     this->start = (char *) start;

     this->end = this->start + size;

     this->ran_out_of_room = false;

     this->head = this->start;

     this->debug_depth = 0;

   }

   template <typename Type>

   inline Type *start_serialize (void)

   {

     DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, +1,

 		     "start [%p..%p] (%lu bytes)",

 		     this->start, this->end,

 		     (unsigned long) (this->end - this->start));

     return start_embed<Type> ();

   }

   inline void end_serialize (void)

   {

     DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, -1,

 		     "end [%p..%p] serialized %d bytes; %s",

 		     this->start, this->end,

 		     (int) (this->head - this->start),

 		     this->ran_out_of_room ? "RAN OUT OF ROOM" : "did not ran out of room");

   }

   template <typename Type>

   inline Type *copy (void)

   {

     assert (!this->ran_out_of_room);

     unsigned int len = this->head - this->start;

     void *p = malloc (len);

     if (p)

       memcpy (p, this->start, len);

     return reinterpret_cast<Type *> (p);

   }

   template <typename Type>

   inline Type *allocate_size (unsigned int size)

   {

     if (unlikely (this->ran_out_of_room || this->end - this->head < ptrdiff_t (size))) {

       this->ran_out_of_room = true;

       return NULL;

     }

     memset (this->head, 0, size);

     char *ret = this->head;

     this->head += size;

     return reinterpret_cast<Type *> (ret);

   }

   template <typename Type>

   inline Type *allocate_min (void)

   {

     return this->allocate_size<Type> (Type::min_size);

   }

   template <typename Type>

   inline Type *start_embed (void)

   {

     Type *ret = reinterpret_cast<Type *> (this->head);

     return ret;

   }

   template <typename Type>

   inline Type *embed (const Type &obj)

   {

     unsigned int size = obj.get_size ();

     Type *ret = this->allocate_size<Type> (size);

     if (unlikely (!ret)) return NULL;

     memcpy (ret, obj, size);

     return ret;

   }

   template <typename Type>

   inline Type *extend_min (Type &obj)

   {

     unsigned int size = obj.min_size;

     assert (this->start <= (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);

     if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;

     return reinterpret_cast<Type *> (&obj);

   }

   template <typename Type>

   inline Type *extend (Type &obj)

   {

     unsigned int size = obj.get_size ();

     assert (this->start < (char *) &obj && (char *) &obj <= this->head && (char *) &obj + size >= this->head);

     if (unlikely (!this->allocate_size<Type> (((char *) &obj) + size - this->head))) return NULL;

     return reinterpret_cast<Type *> (&obj);

   }

   inline void truncate (void *head)

   {

     assert (this->start < head && head <= this->head);

     this->head = (char *) head;

   }

   unsigned int debug_depth;

   char *start, *end, *head;

   bool ran_out_of_room;

 };

 template <typename Type>

 struct Supplier

 {

   inline Supplier (const Type *array, unsigned int len_)

   {

     head = array;

     len = len_;

   }

   inline const Type operator [] (unsigned int i) const

   {

     if (unlikely (i >= len)) return Type ();

     return head[i];

   }

   inline void advance (unsigned int count)

   {

     if (unlikely (count > len))

       count = len;

     len -= count;

     head += count;

   }

   private:

   inline Supplier (const Supplier<Type> &); /* Disallow copy */

   inline Supplier<Type>& operator= (const Supplier<Type> &); /* Disallow copy */

   unsigned int len;

   const Type *head;

 };

 /*

  *

  * The OpenType Font File: Data Types

  */

 /* "The following data types are used in the OpenType font file.

  *  All OpenType fonts use Motorola-style byte ordering (Big Endian):" */

 /*

  * Int types

  */

 template <typename Type, int Bytes> struct BEInt;

 template <typename Type>

 struct BEInt<Type, 2>

 {

   public:

   inline void set (Type i) { hb_be_uint16_put (v,i); }

   inline operator Type (void) const { return hb_be_uint16_get (v); }

   inline bool operator == (const BEInt<Type, 2>& o) const { return hb_be_uint16_eq (v, o.v); }

   inline bool operator != (const BEInt<Type, 2>& o) const { return !(*this == o); }

   private: uint8_t v[2];

 };

 template <typename Type>

 struct BEInt<Type, 4>

 {

   public:

   inline void set (Type i) { hb_be_uint32_put (v,i); }

   inline operator Type (void) const { return hb_be_uint32_get (v); }

   inline bool operator == (const BEInt<Type, 4>& o) const { return hb_be_uint32_eq (v, o.v); }

   inline bool operator != (const BEInt<Type, 4>& o) const { return !(*this == o); }

   private: uint8_t v[4];

 };

 template <typename Type>

 struct BEInt<Type, 3>

 {

   public:

   inline void set (Type i) { hb_be_uint24_put (v,i); }

   inline operator Type (void) const { return hb_be_uint24_get (v); }

   inline bool operator == (const BEInt<Type, 3>& o) const { return hb_be_uint24_eq (v, o.v); }

   inline bool operator != (const BEInt<Type, 3>& o) const { return !(*this == o); }

   private: uint8_t v[3];

 };

 /* Integer types in big-endian order and no alignment requirement */

 template <typename Type, unsigned int Size>

 struct IntType

 {

   inline void set (Type i) { v.set (i); }

   inline operator Type(void) const { return v; }

   inline bool operator == (const IntType<Type,Size> &o) const { return v == o.v; }

   inline bool operator != (const IntType<Type,Size> &o) const { return v != o.v; }

   static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }

   inline int cmp (IntType<Type,Size> va) const { Type a = va; Type b = v; return a < b ? -1 : a == b ? 0 : +1; }

   inline int cmp (Type a) const { Type b = v; return a < b ? -1 : a == b ? 0 : +1; }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (likely (c->check_struct (this)));

   }

   protected:

   BEInt<Type, Size> v;

   public:

   DEFINE_SIZE_STATIC (Size);

 };

 typedef IntType<uint16_t, 2> USHORT;	/* 16-bit unsigned integer. */

 typedef IntType<int16_t,  2> SHORT;	/* 16-bit signed integer. */

 typedef IntType<uint32_t, 4> ULONG;	/* 32-bit unsigned integer. */

 typedef IntType<int32_t,  4> LONG;	/* 32-bit signed integer. */

 typedef IntType<uint32_t, 3> UINT24;	/* 24-bit unsigned integer. */

 /* 16-bit signed integer (SHORT) that describes a quantity in FUnits. */

 typedef SHORT FWORD;

 /* 16-bit unsigned integer (USHORT) that describes a quantity in FUnits. */

 typedef USHORT UFWORD;

 /* Date represented in number of seconds since 12:00 midnight, January 1,

  * 1904. The value is represented as a signed 64-bit integer. */

 struct LONGDATETIME

 {

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (likely (c->check_struct (this)));

   }

   protected:

   LONG major;

   ULONG minor;

   public:

   DEFINE_SIZE_STATIC (8);

 };

 /* Array of four uint8s (length = 32 bits) used to identify a script, language

  * system, feature, or baseline */

 struct Tag : ULONG

 {

   /* What the char* converters return is NOT nul-terminated.  Print using "%.4s" */

   inline operator const char* (void) const { return reinterpret_cast<const char *> (&this->v); }

   inline operator char* (void) { return reinterpret_cast<char *> (&this->v); }

   public:

   DEFINE_SIZE_STATIC (4);

 };

 DEFINE_NULL_DATA (Tag, "    ");

 /* Glyph index number, same as uint16 (length = 16 bits) */

 typedef USHORT GlyphID;

 /* Script/language-system/feature index */

 struct Index : USHORT {

   static const unsigned int NOT_FOUND_INDEX = 0xFFFF;

 };

 DEFINE_NULL_DATA (Index, "\xff\xff");

 /* Offset to a table, same as uint16 (length = 16 bits), Null offset = 0x0000 */

 struct Offset : USHORT

 {

   inline bool is_null (void) const { return 0 == *this; }

   public:

   DEFINE_SIZE_STATIC (2);

 };

 /* LongOffset to a table, same as uint32 (length = 32 bits), Null offset = 0x00000000 */

 struct LongOffset : ULONG

 {

   inline bool is_null (void) const { return 0 == *this; }

   public:

   DEFINE_SIZE_STATIC (4);

 };

 /* CheckSum */

 struct CheckSum : ULONG

 {

   /* This is reference implementation from the spec. */

   static inline uint32_t CalcTableChecksum (const ULONG *Table, uint32_t Length)

   {

     uint32_t Sum = 0L;

     const ULONG *EndPtr = Table+((Length+3) & ~3) / ULONG::static_size;

     while (Table < EndPtr)

       Sum += *Table++;

     return Sum;

   }

   /* Note: data should be 4byte aligned and have 4byte padding at the end. */

   inline void set_for_data (const void *data, unsigned int length)

   { set (CalcTableChecksum ((const ULONG *) data, length)); }

   public:

   DEFINE_SIZE_STATIC (4);

 };

 /*

  * Version Numbers

  */

 struct FixedVersion

 {

   inline uint32_t to_int (void) const { return (major << 16) + minor; }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (c->check_struct (this));

   }

   USHORT major;

   USHORT minor;

   public:

   DEFINE_SIZE_STATIC (4);

 };

 /*

  * Template subclasses of Offset and LongOffset that do the dereferencing.

  * Use: (base+offset)

  */

 template <typename OffsetType, typename Type>

 struct GenericOffsetTo : OffsetType

 {

   inline const Type& operator () (const void *base) const

   {

     unsigned int offset = *this;

     if (unlikely (!offset)) return Null(Type);

     return StructAtOffset<Type> (base, offset);

   }

   inline Type& serialize (hb_serialize_context_t *c, void *base)

   {

     Type *t = c->start_embed<Type> ();

     this->set ((char *) t - (char *) base); /* TODO(serialize) Overflow? */

     return *t;

   }

   inline bool sanitize (hb_sanitize_context_t *c, void *base) {

     TRACE_SANITIZE (this);

     if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);

     unsigned int offset = *this;

     if (unlikely (!offset)) return TRACE_RETURN (true);

     Type &obj = StructAtOffset<Type> (base, offset);

     return TRACE_RETURN (likely (obj.sanitize (c)) || neuter (c));

   }

   template <typename T>

   inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {

     TRACE_SANITIZE (this);

     if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);

     unsigned int offset = *this;

     if (unlikely (!offset)) return TRACE_RETURN (true);

     Type &obj = StructAtOffset<Type> (base, offset);

     return TRACE_RETURN (likely (obj.sanitize (c, user_data)) || neuter (c));

   }

   inline bool try_set (hb_sanitize_context_t *c, const OffsetType &v) {

     if (c->may_edit (this, this->static_size)) {

       this->set (v);

       return true;

     }

     return false;

   }

   /* Set the offset to Null */

   inline bool neuter (hb_sanitize_context_t *c) {

     if (c->may_edit (this, this->static_size)) {

       this->set (0); /* 0 is Null offset */

       return true;

     }

     return false;

   }

 };

 template <typename Base, typename OffsetType, typename Type>

 inline const Type& operator + (const Base &base, const GenericOffsetTo<OffsetType, Type> &offset) { return offset (base); }

 template <typename Base, typename OffsetType, typename Type>

 inline Type& operator + (Base &base, GenericOffsetTo<OffsetType, Type> &offset) { return offset (base); }

 template <typename Type>

 struct OffsetTo : GenericOffsetTo<Offset, Type> {};

 template <typename Type>

 struct LongOffsetTo : GenericOffsetTo<LongOffset, Type> {};

 /*

  * Array Types

  */

 template <typename LenType, typename Type>

 struct GenericArrayOf

 {

   const Type *sub_array (unsigned int start_offset, unsigned int *pcount /* IN/OUT */) const

   {

     unsigned int count = len;

     if (unlikely (start_offset > count))

       count = 0;

     else

       count -= start_offset;

     count = MIN (count, *pcount);

     *pcount = count;

     return array + start_offset;

   }

   inline const Type& operator [] (unsigned int i) const

   {

     if (unlikely (i >= len)) return Null(Type);

     return array[i];

   }

   inline Type& operator [] (unsigned int i)

   {

     return array[i];

   }

   inline unsigned int get_size (void) const

   { return len.static_size + len * Type::static_size; }

   inline bool serialize (hb_serialize_context_t *c,

 			 unsigned int items_len)

   {

     TRACE_SERIALIZE (this);

     if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);

     len.set (items_len); /* TODO(serialize) Overflow? */

     if (unlikely (!c->extend (*this))) return TRACE_RETURN (false);

     return TRACE_RETURN (true);

   }

   inline bool serialize (hb_serialize_context_t *c,

 			 Supplier<Type> &items,

 			 unsigned int items_len)

   {

     TRACE_SERIALIZE (this);

     if (unlikely (!serialize (c, items_len))) return TRACE_RETURN (false);

     for (unsigned int i = 0; i < items_len; i++)

       array[i] = items[i];

     items.advance (items_len);

     return TRACE_RETURN (true);

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);

     /* Note: for structs that do not reference other structs,

      * we do not need to call their sanitize() as we already did

      * a bound check on the aggregate array size.  We just include

      * a small unreachable expression to make sure the structs

      * pointed to do have a simple sanitize(), ie. they do not

      * reference other structs via offsets.

      */

     (void) (false && array[0].sanitize (c));

     return TRACE_RETURN (true);

   }

   inline bool sanitize (hb_sanitize_context_t *c, void *base) {

     TRACE_SANITIZE (this);

     if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);

     unsigned int count = len;

     for (unsigned int i = 0; i < count; i++)

       if (unlikely (!array[i].sanitize (c, base)))

         return TRACE_RETURN (false);

     return TRACE_RETURN (true);

   }

   template <typename T>

   inline bool sanitize (hb_sanitize_context_t *c, void *base, T user_data) {

     TRACE_SANITIZE (this);

     if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);

     unsigned int count = len;

     for (unsigned int i = 0; i < count; i++)

       if (unlikely (!array[i].sanitize (c, base, user_data)))

         return TRACE_RETURN (false);

     return TRACE_RETURN (true);

   }

   private:

   inline bool sanitize_shallow (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (c->check_struct (this) && c->check_array (this, Type::static_size, len));

   }

   public:

   LenType len;

   Type array[VAR];

   public:

   DEFINE_SIZE_ARRAY (sizeof (LenType), array);

 };

 /* An array with a USHORT number of elements. */

 template <typename Type>

 struct ArrayOf : GenericArrayOf<USHORT, Type> {};

 /* An array with a ULONG number of elements. */

 template <typename Type>

 struct LongArrayOf : GenericArrayOf<ULONG, Type> {};

 /* Array of Offset's */

 template <typename Type>

 struct OffsetArrayOf : ArrayOf<OffsetTo<Type> > {};

 /* Array of LongOffset's */

 template <typename Type>

 struct LongOffsetArrayOf : ArrayOf<LongOffsetTo<Type> > {};

 /* LongArray of LongOffset's */

 template <typename Type>

 struct LongOffsetLongArrayOf : LongArrayOf<LongOffsetTo<Type> > {};

 /* Array of offsets relative to the beginning of the array itself. */

 template <typename Type>

 struct OffsetListOf : OffsetArrayOf<Type>

 {

   inline const Type& operator [] (unsigned int i) const

   {

     if (unlikely (i >= this->len)) return Null(Type);

     return this+this->array[i];

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this));

   }

   template <typename T>

   inline bool sanitize (hb_sanitize_context_t *c, T user_data) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (OffsetArrayOf<Type>::sanitize (c, this, user_data));

   }

 };

 /* An array with a USHORT number of elements,

  * starting at second element. */

 template <typename Type>

 struct HeadlessArrayOf

 {

   inline const Type& operator [] (unsigned int i) const

   {

     if (unlikely (i >= len || !i)) return Null(Type);

     return array[i-1];

   }

   inline unsigned int get_size (void) const

   { return len.static_size + (len ? len - 1 : 0) * Type::static_size; }

   inline bool serialize (hb_serialize_context_t *c,

 			 Supplier<Type> &items,

 			 unsigned int items_len)

   {

     TRACE_SERIALIZE (this);

     if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);

     len.set (items_len); /* TODO(serialize) Overflow? */

     if (unlikely (!items_len)) return TRACE_RETURN (true);

     if (unlikely (!c->extend (*this))) return TRACE_RETURN (false);

     for (unsigned int i = 0; i < items_len - 1; i++)

       array[i] = items[i];

     items.advance (items_len - 1);

     return TRACE_RETURN (true);

   }

   inline bool sanitize_shallow (hb_sanitize_context_t *c) {

     return c->check_struct (this)

 	&& c->check_array (this, Type::static_size, len);

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (unlikely (!sanitize_shallow (c))) return TRACE_RETURN (false);

     /* Note: for structs that do not reference other structs,

      * we do not need to call their sanitize() as we already did

      * a bound check on the aggregate array size.  We just include

      * a small unreachable expression to make sure the structs

      * pointed to do have a simple sanitize(), ie. they do not

      * reference other structs via offsets.

      */

     (void) (false && array[0].sanitize (c));

     return TRACE_RETURN (true);

   }

   USHORT len;

   Type array[VAR];

   public:

   DEFINE_SIZE_ARRAY (sizeof (USHORT), array);

 };

 /* An array with sorted elements.  Supports binary searching. */

 template <typename Type>

 struct SortedArrayOf : ArrayOf<Type> {

   template <typename SearchType>

   inline int search (const SearchType &x) const

   {

     /* Hand-coded bsearch here since this is in the hot inner loop. */

     int min = 0, max = (int) this->len - 1;

     while (min <= max)

     {

       int mid = (min + max) / 2;

       int c = this->array[mid].cmp (x);

       if (c < 0)

         max = mid - 1;

       else if (c > 0)

         min = mid + 1;

       else

         return mid;

     }

     return -1;

   }

 };

 } /* namespace OT */

 #endif /* HB_OPEN_TYPE_PRIVATE_HH */