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

568 lines
17 KiB
C++

/*
* Copyright (C) 2007,2008,2009 Red Hat, Inc.
*
* This is part of HarfBuzz, an OpenType Layout engine 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
*/
#ifndef HB_OPEN_TYPES_PRIVATE_HH
#define HB_OPEN_TYPES_PRIVATE_HH
#include "hb-private.h"
#include "hb-blob.h"
#define NO_INDEX ((unsigned int) 0xFFFF)
#define NO_CONTEXT ((unsigned int) 0x110000)
#define NOT_COVERED ((unsigned int) 0x110000)
#define MAX_NESTING_LEVEL 8
/*
* Casts
*/
#define CONST_CHARP(X) (reinterpret_cast<const char *>(X))
#define DECONST_CHARP(X) ((char *)reinterpret_cast<const char *>(X))
#define CHARP(X) (reinterpret_cast<char *>(X))
#define CONST_CAST(T,X,Ofs) (*(reinterpret_cast<const T *>(CONST_CHARP(&(X)) + Ofs)))
#define DECONST_CAST(T,X,Ofs) (*(reinterpret_cast<T *>((char *)CONST_CHARP(&(X)) + Ofs)))
#define CAST(T,X,Ofs) (*(reinterpret_cast<T *>(CHARP(&(X)) + Ofs)))
#define CONST_NEXT(T,X) (*(reinterpret_cast<const T *>(CONST_CHARP(&(X)) + (X).get_size ())))
#define NEXT(T,X) (*(reinterpret_cast<T *>(CHARP(&(X)) + (X).get_size ())))
/*
* Class features
*/
/* Null objects */
/* Global nul-content Null pool. Enlarge as necessary. */
static const char NullPool[16] = "";
/* Generic template for nul-content sizeof-sized Null objects. */
template <typename Type>
struct Null
{
ASSERT_STATIC (sizeof (Type) <= sizeof (NullPool));
static inline const Type &get () { return *(const Type*)NullPool; }
};
/* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
#define DEFINE_NULL_DATA(Type, size, data) \
static const char _Null##Type[size] = data; \
template <> \
struct Null <Type> \
{ \
static inline const Type &get () { return *(const Type*)_Null##Type; } \
}
/* Accessor macro. */
#define Null(Type) (Null<Type>::get())
#define ASSERT_SIZE_DATA(Type, size, data) \
ASSERT_SIZE (Type, size); \
DEFINE_NULL_DATA (Type, size, data)
/* get_for_data() is a static class method returning a reference to an
* instance of Type located at the input data location. It's just a
* fancy, NULL-safe, cast! */
#define STATIC_DEFINE_GET_FOR_DATA(Type) \
static inline const Type& get_for_data (const char *data) \
{ \
if (HB_UNLIKELY (data == NULL)) return Null(Type); \
return *(const Type*)data; \
}
/* Like get_for_data(), but checks major version first. */
#define STATIC_DEFINE_GET_FOR_DATA_CHECK_MAJOR_VERSION(Type, MajorMin, MajorMax) \
static inline const Type& get_for_data (const char *data) \
{ \
if (HB_UNLIKELY (data == NULL)) return Null(Type); \
const Type& t = *(const Type*)data; \
if (HB_UNLIKELY (t.version.major < MajorMin || t.version.major > MajorMax)) return Null(Type); \
return t; \
}
/*
* Sanitize
*/
#if HB_DEBUG
#define SANITIZE_DEBUG_ARG_DEF , unsigned int sanitize_depth
#define SANITIZE_DEBUG_ARG , sanitize_depth + 1
#define SANITIZE_DEBUG_ARG_INIT , 1
#define SANITIZE_DEBUG() \
HB_STMT_START { \
if (sanitize_depth < HB_DEBUG) \
fprintf (stderr, "SANITIZE(%p) %-*d-> %s\n", \
(CONST_CHARP (this) == NullPool) ? 0 : this, \
sanitize_depth, sanitize_depth, \
__PRETTY_FUNCTION__); \
} HB_STMT_END
#else
#define SANITIZE_DEBUG_ARG_DEF
#define SANITIZE_DEBUG_ARG
#define SANITIZE_DEBUG_ARG_INIT
#define SANITIZE_DEBUG() HB_STMT_START {} HB_STMT_END
#endif
typedef struct _hb_sanitize_context_t hb_sanitize_context_t;
struct _hb_sanitize_context_t
{
const char *start, *end;
int edit_count;
hb_blob_t *blob;
};
static HB_GNUC_UNUSED void
_hb_sanitize_init (hb_sanitize_context_t *context,
hb_blob_t *blob)
{
context->blob = blob;
context->start = hb_blob_lock (blob);
context->end = context->start + hb_blob_get_length (blob);
context->edit_count = 0;
#if HB_DEBUG
fprintf (stderr, "sanitize %p init [%p..%p] (%u bytes)\n",
context->blob, context->start, context->end, context->end - context->start);
#endif
}
static HB_GNUC_UNUSED void
_hb_sanitize_fini (hb_sanitize_context_t *context,
bool unlock)
{
#if HB_DEBUG
fprintf (stderr, "sanitize %p fini [%p..%p] %u edit requests\n",
context->blob, context->start, context->end, context->edit_count);
#endif
if (unlock)
hb_blob_unlock (context->blob);
}
static HB_GNUC_UNUSED inline bool
_hb_sanitize_edit (hb_sanitize_context_t *context,
const char *base HB_GNUC_UNUSED,
unsigned int len HB_GNUC_UNUSED)
{
bool perm = hb_blob_try_writeable_inplace (context->blob);
context->edit_count++;
#if HB_DEBUG
fprintf (stderr, "sanitize %p edit %u requested for [%p..%p] (%d bytes) in [%p..%p] -> %s\n",
context->blob,
context->edit_count,
base, base+len, len,
context->start, context->end,
perm ? "granted" : "rejected");
#endif
return perm;
}
#define SANITIZE_ARG_DEF \
hb_sanitize_context_t *context SANITIZE_DEBUG_ARG_DEF
#define SANITIZE_ARG \
context SANITIZE_DEBUG_ARG
#define SANITIZE_ARG_INIT \
&context SANITIZE_DEBUG_ARG_INIT
#define SANITIZE(X) HB_LIKELY ((X).sanitize (SANITIZE_ARG))
#define SANITIZE2(X,Y) (SANITIZE (X) && SANITIZE (Y))
#define SANITIZE_THIS(X) HB_LIKELY ((X).sanitize (SANITIZE_ARG, CONST_CHARP(this)))
#define SANITIZE_THIS2(X,Y) (SANITIZE_THIS (X) && SANITIZE_THIS (Y))
#define SANITIZE_THIS3(X,Y,Z) (SANITIZE_THIS (X) && SANITIZE_THIS (Y) && SANITIZE_THIS(Z))
#define SANITIZE_BASE(X,B) HB_LIKELY ((X).sanitize (SANITIZE_ARG, B))
#define SANITIZE_BASE2(X,Y,B) (SANITIZE_BASE (X,B) && SANITIZE_BASE (Y,B))
#define SANITIZE_SELF() SANITIZE_OBJ (*this)
#define SANITIZE_OBJ(X) SANITIZE_MEM(&(X), sizeof (X))
#define SANITIZE_GET_SIZE() SANITIZE_SELF() && SANITIZE_MEM (this, this->get_size ())
/* TODO Optimize this if L is fixed (gcc magic) */
#define SANITIZE_MEM(B,L) \
HB_LIKELY (context->start <= CONST_CHARP(B) && \
CONST_CHARP(B) <= context->end && \
(unsigned int) (context->end - CONST_CHARP(B)) >= (unsigned int) (L))
#define NEUTER(Var, Val) \
(SANITIZE_OBJ (Var) && \
_hb_sanitize_edit (context, CONST_CHARP(&(Var)), sizeof (Var)) && \
((Var) = (Val), true))
/* Template to sanitize an object. */
template <typename Type>
struct Sanitizer
{
static hb_blob_t *sanitize (hb_blob_t *blob) {
hb_sanitize_context_t context;
bool sane;
/* TODO is_sane() stuff */
retry:
#if HB_DEBUG
fprintf (stderr, "Sanitizer %p start %s\n", blob, __PRETTY_FUNCTION__);
#endif
_hb_sanitize_init (&context, blob);
Type *t = &CAST (Type, *DECONST_CHARP(context.start), 0);
sane = t->sanitize (SANITIZE_ARG_INIT);
if (sane) {
if (context.edit_count) {
#if HB_DEBUG
fprintf (stderr, "Sanitizer %p passed first round with %d edits; going a second round %s\n",
blob, context.edit_count, __PRETTY_FUNCTION__);
#endif
/* sanitize again to ensure not toe-stepping */
context.edit_count = 0;
sane = t->sanitize (SANITIZE_ARG_INIT);
if (context.edit_count) {
#if HB_DEBUG
fprintf (stderr, "Sanitizer %p requested %d edits in second round; failing %s\n",
blob, context.edit_count, __PRETTY_FUNCTION__);
#endif
sane = false;
}
}
_hb_sanitize_fini (&context, true);
} else {
unsigned int edit_count = context.edit_count;
_hb_sanitize_fini (&context, true);
if (edit_count && !hb_blob_is_writeable (blob) && hb_blob_try_writeable (blob)) {
/* ok, we made it writeable by relocating. try again */
#if HB_DEBUG
fprintf (stderr, "Sanitizer %p retry %s\n", blob, __PRETTY_FUNCTION__);
#endif
goto retry;
}
}
#if HB_DEBUG
fprintf (stderr, "Sanitizer %p %s %s\n", blob, sane ? "passed" : "failed", __PRETTY_FUNCTION__);
#endif
if (sane)
return blob;
else {
hb_blob_destroy (blob);
return hb_blob_create_empty ();
}
}
static const Type& lock_instance (hb_blob_t *blob) {
return Type::get_for_data (hb_blob_lock (blob));
}
};
/*
*
* 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
*/
/* TODO On machines that allow unaligned access, use this version. */
#define _DEFINE_INT_TYPE1_UNALIGNED(NAME, TYPE, BIG_ENDIAN, BYTES) \
struct NAME \
{ \
inline NAME& operator = (TYPE i) { (TYPE&) v = BIG_ENDIAN (i); return *this; } \
inline operator TYPE(void) const { return BIG_ENDIAN ((TYPE&) v); } \
inline bool operator== (NAME o) const { return (TYPE&) v == (TYPE&) o.v; } \
inline bool sanitize (SANITIZE_ARG_DEF) { \
SANITIZE_DEBUG (); \
return SANITIZE_SELF (); \
} \
private: unsigned char v[BYTES]; \
}; \
ASSERT_SIZE (NAME, BYTES)
#define DEFINE_INT_TYPE1(NAME, TYPE, BIG_ENDIAN, BYTES) \
struct NAME \
{ \
inline NAME& operator = (TYPE i) { BIG_ENDIAN##_put_unaligned(v, i); return *this; } \
inline operator TYPE(void) const { return BIG_ENDIAN##_get_unaligned (v); } \
inline bool operator== (NAME o) const { return BIG_ENDIAN##_cmp_unaligned (v, o.v); } \
inline bool sanitize (SANITIZE_ARG_DEF) { \
SANITIZE_DEBUG (); \
return SANITIZE_SELF (); \
} \
private: unsigned char v[BYTES]; \
}; \
ASSERT_SIZE (NAME, BYTES)
#define DEFINE_INT_TYPE0(NAME, type, b) DEFINE_INT_TYPE1 (NAME, type##_t, hb_be_##type, b)
#define DEFINE_INT_TYPE(NAME, u, w) DEFINE_INT_TYPE0 (NAME, u##int##w, (w / 8))
DEFINE_INT_TYPE (USHORT, u, 16); /* 16-bit unsigned integer. */
DEFINE_INT_TYPE (SHORT, , 16); /* 16-bit signed integer. */
DEFINE_INT_TYPE (ULONG, u, 32); /* 32-bit unsigned integer. */
DEFINE_INT_TYPE (LONG, , 32); /* 32-bit signed integer. */
/* Array of four uint8s (length = 32 bits) used to identify a script, language
* system, feature, or baseline */
struct Tag : ULONG
{
inline Tag (const Tag &o) { *(ULONG*)this = (ULONG&) o; }
inline Tag (uint32_t i) { *(ULONG*)this = i; }
inline Tag (const char *c) { *(ULONG*)this = *(ULONG*)c; }
inline bool operator== (const char *c) const { return *(ULONG*)this == *(ULONG*)c; }
/* What the char* converters return is NOT nul-terminated. Print using "%.4s" */
inline operator const char* (void) const { return CONST_CHARP(this); }
inline operator char* (void) { return CHARP(this); }
inline bool sanitize (SANITIZE_ARG_DEF) {
SANITIZE_DEBUG ();
/* Note: Only accept ASCII-visible tags (mind DEL)
* This is one of the few times (only time?) we check
* for data integrity, as opposed o just boundary checks
*/
return SANITIZE_SELF () && (((uint32_t) *this) & 0x80808080) == 0;
}
};
ASSERT_SIZE (Tag, 4);
#define _NULL_TAG_INIT {' ', ' ', ' ', ' '}
DEFINE_NULL_DATA (Tag, 4, _NULL_TAG_INIT);
#undef _NULL_TAG_INIT
/* Glyph index number, same as uint16 (length = 16 bits) */
typedef USHORT GlyphID;
/* Offset to a table, same as uint16 (length = 16 bits), Null offset = 0x0000 */
typedef USHORT Offset;
/* LongOffset to a table, same as uint32 (length = 32 bits), Null offset = 0x00000000 */
typedef ULONG LongOffset;
/* CheckSum */
struct CheckSum : ULONG
{
static uint32_t CalcTableChecksum (ULONG *Table, uint32_t Length)
{
uint32_t Sum = 0L;
ULONG *EndPtr = Table+((Length+3) & ~3) / sizeof(ULONG);
while (Table < EndPtr)
Sum += *Table++;
return Sum;
}
};
ASSERT_SIZE (CheckSum, 4);
/*
* Version Numbers
*/
struct FixedVersion
{
inline operator uint32_t (void) const { return (major << 16) + minor; }
inline bool sanitize (SANITIZE_ARG_DEF) {
SANITIZE_DEBUG ();
return SANITIZE_SELF ();
}
USHORT major;
USHORT minor;
};
ASSERT_SIZE (FixedVersion, 4);
/*
* Template subclasses of Offset and LongOffset that do the dereferencing.
* Use: (this+memberName)
*/
template <typename OffsetType, typename Type>
struct GenericOffsetTo : OffsetType
{
inline const Type& operator() (const void *base) const
{
unsigned int offset = *this;
if (HB_UNLIKELY (!offset)) return Null(Type);
return CONST_CAST(Type, *CONST_CHARP(base), offset);
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base) {
SANITIZE_DEBUG ();
if (!SANITIZE_SELF ()) return false;
unsigned int offset = *this;
if (HB_UNLIKELY (!offset)) return true;
return SANITIZE (CAST(Type, *DECONST_CHARP(base), offset)) || NEUTER (DECONST_CAST(OffsetType,*this,0), 0);
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base, const void *base2) {
SANITIZE_DEBUG ();
if (!SANITIZE_SELF ()) return false;
unsigned int offset = *this;
if (HB_UNLIKELY (!offset)) return true;
return SANITIZE_BASE (CAST(Type, *DECONST_CHARP(base), offset), base2) || NEUTER (DECONST_CAST(OffsetType,*this,0), 0);
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base, unsigned int user_data) {
SANITIZE_DEBUG ();
if (!SANITIZE_SELF ()) return false;
unsigned int offset = *this;
if (HB_UNLIKELY (!offset)) return true;
return SANITIZE_BASE (CAST(Type, *DECONST_CHARP(base), offset), user_data) || NEUTER (DECONST_CAST(OffsetType,*this,0), 0);
}
};
template <typename Base, typename OffsetType, typename Type>
inline const Type& operator + (const 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
{
inline const Type& operator [] (unsigned int i) const
{
if (HB_UNLIKELY (i >= len)) return Null(Type);
return array[i];
}
inline unsigned int get_size () const
{ return sizeof (len) + len * sizeof (array[0]); }
inline bool sanitize (SANITIZE_ARG_DEF) {
SANITIZE_DEBUG ();
if (!SANITIZE_GET_SIZE()) return false;
/* Note; for non-recursive types, this is not much needed
unsigned int count = len;
for (unsigned int i = 0; i < count; i++)
if (!SANITIZE (array[i]))
return false;
*/
return true;
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base) {
SANITIZE_DEBUG ();
if (!SANITIZE_GET_SIZE()) return false;
unsigned int count = len;
for (unsigned int i = 0; i < count; i++)
if (!array[i].sanitize (SANITIZE_ARG, base))
return false;
return true;
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base, const void *base2) {
SANITIZE_DEBUG ();
if (!SANITIZE_GET_SIZE()) return false;
unsigned int count = len;
for (unsigned int i = 0; i < count; i++)
if (!array[i].sanitize (SANITIZE_ARG, base, base2))
return false;
return true;
}
inline bool sanitize (SANITIZE_ARG_DEF, const void *base, unsigned int user_data) {
SANITIZE_DEBUG ();
if (!SANITIZE_GET_SIZE()) return false;
unsigned int count = len;
for (unsigned int i = 0; i < count; i++)
if (!array[i].sanitize (SANITIZE_ARG, base, user_data))
return false;
return true;
}
LenType len;
Type 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> > {};
/* 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 (HB_UNLIKELY (i >= len || !i)) return Null(Type);
return array[i-1];
}
inline unsigned int get_size () const
{ return sizeof (len) + (len ? len - 1 : 0) * sizeof (array[0]); }
inline bool sanitize (SANITIZE_ARG_DEF) {
SANITIZE_DEBUG ();
if (!SANITIZE_GET_SIZE()) return false;
/* Note; for non-recursive types, this is not much needed
unsigned int count = len ? len - 1 : 0;
for (unsigned int i = 0; i < count; i++)
if (!SANITIZE (array[i]))
return false;
*/
return true;
}
USHORT len;
Type array[];
};
#endif /* HB_OPEN_TYPES_PRIVATE_HH */