/*
* Copyright © 2017 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.
*
* Google Author(s): Behdad Esfahbod
*/
#ifndef HB_AAT_LAYOUT_COMMON_HH
#define HB_AAT_LAYOUT_COMMON_HH
#include "hb-aat-layout.hh"
namespace AAT {
using namespace OT;
/*
* Binary Searching Tables
*/
struct BinSearchHeader
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
HBUINT16 unitSize; /* Size of a lookup unit for this search in bytes. */
HBUINT16 nUnits; /* Number of units of the preceding size to be searched. */
HBUINT16 searchRange; /* The value of unitSize times the largest power of 2
* that is less than or equal to the value of nUnits. */
HBUINT16 entrySelector; /* The log base 2 of the largest power of 2 less than
* or equal to the value of nUnits. */
HBUINT16 rangeShift; /* The value of unitSize times the difference of the
* value of nUnits minus the largest power of 2 less
* than or equal to the value of nUnits. */
public:
DEFINE_SIZE_STATIC (10);
};
template <typename Type>
struct BinSearchArrayOf
{
inline const Type& operator [] (unsigned int i) const
{
if (unlikely (i >= header.nUnits)) return Null(Type);
return StructAtOffset<Type> (&bytesZ, i * header.unitSize);
}
inline Type& operator [] (unsigned int i)
{
return StructAtOffset<Type> (&bytesZ, i * header.unitSize);
}
inline unsigned int get_size (void) const
{ return header.static_size + header.nUnits * header.unitSize; }
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (unlikely (!sanitize_shallow (c))) return_trace (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 && StructAtOffset<Type> (&bytesZ, 0).sanitize (c));
return_trace (true);
}
inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
{
TRACE_SANITIZE (this);
if (unlikely (!sanitize_shallow (c))) return_trace (false);
unsigned int count = header.nUnits;
for (unsigned int i = 0; i < count; i++)
if (unlikely (!(*this)[i].sanitize (c, base)))
return_trace (false);
return_trace (true);
}
template <typename T>
inline const Type *bsearch (const T &key) const
{
unsigned int size = header.unitSize;
int min = 0, max = (int) header.nUnits - 1;
while (min <= max)
{
int mid = (min + max) / 2;
const Type *p = (const Type *) (((const char *) &bytesZ) + (mid * size));
int c = p->cmp (key);
if (c < 0)
max = mid - 1;
else if (c > 0)
min = mid + 1;
else
return p;
}
return nullptr;
}
private:
inline bool sanitize_shallow (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (header.sanitize (c) &&
Type::static_size >= header.unitSize &&
c->check_array (bytesZ.arrayZ, header.nUnits, header.unitSize));
}
protected:
BinSearchHeader header;
UnsizedArrayOf<HBUINT8> bytesZ;
public:
DEFINE_SIZE_ARRAY (10, bytesZ);
};
/*
* Lookup Table
*/
template <typename T> struct Lookup;
template <typename T>
struct LookupFormat0
{
friend struct Lookup<T>;
private:
inline const T* get_value (hb_codepoint_t glyph_id, unsigned int num_glyphs) const
{
if (unlikely (glyph_id >= num_glyphs)) return nullptr;
return &arrayZ[glyph_id];
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (arrayZ.sanitize (c, c->get_num_glyphs ()));
}
protected:
HBUINT16 format; /* Format identifier--format = 0 */
UnsizedArrayOf<T>
arrayZ; /* Array of lookup values, indexed by glyph index. */
public:
DEFINE_SIZE_ARRAY (2, arrayZ);
};
template <typename T>
struct LookupSegmentSingle
{
inline int cmp (hb_codepoint_t g) const {
return g < first ? -1 : g <= last ? 0 : +1 ;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && value.sanitize (c));
}
GlyphID last; /* Last GlyphID in this segment */
GlyphID first; /* First GlyphID in this segment */
T value; /* The lookup value (only one) */
public:
DEFINE_SIZE_STATIC (4 + T::static_size);
};
template <typename T>
struct LookupFormat2
{
friend struct Lookup<T>;
private:
inline const T* get_value (hb_codepoint_t glyph_id) const
{
const LookupSegmentSingle<T> *v = segments.bsearch (glyph_id);
return v ? &v->value : nullptr;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (segments.sanitize (c));
}
protected:
HBUINT16 format; /* Format identifier--format = 2 */
BinSearchArrayOf<LookupSegmentSingle<T> >
segments; /* The actual segments. These must already be sorted,
* according to the first word in each one (the last
* glyph in each segment). */
public:
DEFINE_SIZE_ARRAY (8, segments);
};
template <typename T>
struct LookupSegmentArray
{
inline const T* get_value (hb_codepoint_t glyph_id, const void *base) const
{
return first <= glyph_id && glyph_id <= last ? &(base+valuesZ)[glyph_id - first] : nullptr;
}
inline int cmp (hb_codepoint_t g) const {
return g < first ? -1 : g <= last ? 0 : +1 ;
}
inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
first <= last &&
valuesZ.sanitize (c, base, last - first + 1));
}
GlyphID last; /* Last GlyphID in this segment */
GlyphID first; /* First GlyphID in this segment */
OffsetTo<UnsizedArrayOf<T>, HBUINT16, false>
valuesZ; /* A 16-bit offset from the start of
* the table to the data. */
public:
DEFINE_SIZE_STATIC (6);
};
template <typename T>
struct LookupFormat4
{
friend struct Lookup<T>;
private:
inline const T* get_value (hb_codepoint_t glyph_id) const
{
const LookupSegmentArray<T> *v = segments.bsearch (glyph_id);
return v ? v->get_value (glyph_id, this) : nullptr;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (segments.sanitize (c, this));
}
protected:
HBUINT16 format; /* Format identifier--format = 2 */
BinSearchArrayOf<LookupSegmentArray<T> >
segments; /* The actual segments. These must already be sorted,
* according to the first word in each one (the last
* glyph in each segment). */
public:
DEFINE_SIZE_ARRAY (8, segments);
};
template <typename T>
struct LookupSingle
{
inline int cmp (hb_codepoint_t g) const { return glyph.cmp (g); }
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && value.sanitize (c));
}
GlyphID glyph; /* Last GlyphID */
T value; /* The lookup value (only one) */
public:
DEFINE_SIZE_STATIC (4 + T::static_size);
};
template <typename T>
struct LookupFormat6
{
friend struct Lookup<T>;
private:
inline const T* get_value (hb_codepoint_t glyph_id) const
{
const LookupSingle<T> *v = entries.bsearch (glyph_id);
return v ? &v->value : nullptr;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (entries.sanitize (c));
}
protected:
HBUINT16 format; /* Format identifier--format = 6 */
BinSearchArrayOf<LookupSingle<T> >
entries; /* The actual entries, sorted by glyph index. */
public:
DEFINE_SIZE_ARRAY (8, entries);
};
template <typename T>
struct LookupFormat8
{
friend struct Lookup<T>;
private:
inline const T* get_value (hb_codepoint_t glyph_id) const
{
return firstGlyph <= glyph_id && glyph_id - firstGlyph < glyphCount ? &valueArrayZ[glyph_id - firstGlyph] : nullptr;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && valueArrayZ.sanitize (c, glyphCount));
}
protected:
HBUINT16 format; /* Format identifier--format = 6 */
GlyphID firstGlyph; /* First glyph index included in the trimmed array. */
HBUINT16 glyphCount; /* Total number of glyphs (equivalent to the last
* glyph minus the value of firstGlyph plus 1). */
UnsizedArrayOf<T>
valueArrayZ; /* The lookup values (indexed by the glyph index
* minus the value of firstGlyph). */
public:
DEFINE_SIZE_ARRAY (6, valueArrayZ);
};
template <typename T>
struct Lookup
{
inline const T* get_value (hb_codepoint_t glyph_id, unsigned int num_glyphs) const
{
switch (u.format) {
case 0: return u.format0.get_value (glyph_id, num_glyphs);
case 2: return u.format2.get_value (glyph_id);
case 4: return u.format4.get_value (glyph_id);
case 6: return u.format6.get_value (glyph_id);
case 8: return u.format8.get_value (glyph_id);
default:return nullptr;
}
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (!u.format.sanitize (c)) return_trace (false);
switch (u.format) {
case 0: return_trace (u.format0.sanitize (c));
case 2: return_trace (u.format2.sanitize (c));
case 4: return_trace (u.format4.sanitize (c));
case 6: return_trace (u.format6.sanitize (c));
case 8: return_trace (u.format8.sanitize (c));
default:return_trace (true);
}
}
protected:
union {
HBUINT16 format; /* Format identifier */
LookupFormat0<T> format0;
LookupFormat2<T> format2;
LookupFormat4<T> format4;
LookupFormat6<T> format6;
LookupFormat8<T> format8;
} u;
public:
DEFINE_SIZE_UNION (2, format);
};
/*
* Extended State Table
*/
template <typename T>
struct Entry
{
inline bool sanitize (hb_sanitize_context_t *c, unsigned int count) const
{
TRACE_SANITIZE (this);
/* Note, we don't recurse-sanitize data because we don't access it.
* That said, in our DEFINE_SIZE_STATIC we access T::static_size,
* which ensures that data has a simple sanitize(). To be determined
* if I need to remove that as well. */
return_trace (c->check_struct (this));
}
public:
HBUINT16 newState; /* Byte offset from beginning of state table
* to the new state. Really?!?! Or just state
* number? The latter in morx for sure. */
HBUINT16 flags; /* Table specific. */
T data; /* Optional offsets to per-glyph tables. */
public:
DEFINE_SIZE_STATIC (4 + T::static_size);
};
template <>
struct Entry<void>
{
inline bool sanitize (hb_sanitize_context_t *c, unsigned int count) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
public:
HBUINT16 newState; /* Byte offset from beginning of state table to the new state. */
HBUINT16 flags; /* Table specific. */
public:
DEFINE_SIZE_STATIC (4);
};
template <typename Extra>
struct StateTable
{
enum State
{
STATE_START_OF_TEXT = 0,
STATE_START_OF_LINE = 1,
};
enum Class
{
CLASS_END_OF_TEXT = 0,
CLASS_OUT_OF_BOUNDS = 1,
CLASS_DELETED_GLYPH = 2,
CLASS_END_OF_LINE = 3,
};
inline unsigned int get_class (hb_codepoint_t glyph_id, unsigned int num_glyphs) const
{
const HBUINT16 *v = (this+classTable).get_value (glyph_id, num_glyphs);
return v ? (unsigned) *v : (unsigned) CLASS_OUT_OF_BOUNDS;
}
inline const Entry<Extra> *get_entries () const
{
return (this+entryTable).arrayZ;
}
inline const Entry<Extra> *get_entryZ (unsigned int state, unsigned int klass) const
{
if (unlikely (klass >= nClasses)) return nullptr;
const HBUINT16 *states = (this+stateArrayTable).arrayZ;
const Entry<Extra> *entries = (this+entryTable).arrayZ;
unsigned int entry = states[state * nClasses + klass];
return &entries[entry];
}
inline bool sanitize (hb_sanitize_context_t *c,
unsigned int *num_entries_out = nullptr) const
{
TRACE_SANITIZE (this);
if (unlikely (!(c->check_struct (this) &&
classTable.sanitize (c, this)))) return_trace (false);
const HBUINT16 *states = (this+stateArrayTable).arrayZ;
const Entry<Extra> *entries = (this+entryTable).arrayZ;
unsigned int num_states = 1;
unsigned int num_entries = 0;
unsigned int state = 0;
unsigned int entry = 0;
while (state < num_states)
{
if (unlikely (!c->check_array (states,
num_states,
states[0].static_size * nClasses)))
return_trace (false);
{ /* Sweep new states. */
const HBUINT16 *stop = &states[num_states * nClasses];
for (const HBUINT16 *p = &states[state * nClasses]; p < stop; p++)
num_entries = MAX<unsigned int> (num_entries, *p + 1);
state = num_states;
}
if (unlikely (!c->check_array (entries, num_entries)))
return_trace (false);
{ /* Sweep new entries. */
const Entry<Extra> *stop = &entries[num_entries];
for (const Entry<Extra> *p = &entries[entry]; p < stop; p++)
num_states = MAX<unsigned int> (num_states, p->newState + 1);
entry = num_entries;
}
}
if (num_entries_out)
*num_entries_out = num_entries;
return_trace (true);
}
protected:
HBUINT32 nClasses; /* Number of classes, which is the number of indices
* in a single line in the state array. */
LOffsetTo<Lookup<HBUINT16>, false>
classTable; /* Offset to the class table. */
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
stateArrayTable;/* Offset to the state array. */
LOffsetTo<UnsizedArrayOf<Entry<Extra> >, false>
entryTable; /* Offset to the entry array. */
public:
DEFINE_SIZE_STATIC (16);
};
template <typename EntryData>
struct StateTableDriver
{
inline StateTableDriver (const StateTable<EntryData> &machine_,
hb_buffer_t *buffer_,
hb_face_t *face_) :
machine (machine_),
buffer (buffer_),
num_glyphs (face_->get_num_glyphs ()) {}
template <typename context_t>
inline void drive (context_t *c)
{
hb_glyph_info_t *info = buffer->info;
if (!c->in_place)
buffer->clear_output ();
unsigned int state = StateTable<EntryData>::STATE_START_OF_TEXT;
bool last_was_dont_advance = false;
for (buffer->idx = 0;;)
{
unsigned int klass = buffer->idx < buffer->len ?
machine.get_class (info[buffer->idx].codepoint, num_glyphs) :
(unsigned) StateTable<EntryData>::CLASS_END_OF_TEXT;
const Entry<EntryData> *entry = machine.get_entryZ (state, klass);
if (unlikely (!entry))
break;
/* Unsafe-to-break before this if not in state 0, as things might
* go differently if we start from state 0 here. */
if (state && buffer->idx)
{
/* If there's no action and we're just epsilon-transitioning to state 0,
* safe to break. */
if (c->is_actionable (this, entry) ||
!(entry->newState == StateTable<EntryData>::STATE_START_OF_TEXT &&
entry->flags == context_t::DontAdvance))
buffer->unsafe_to_break (buffer->idx - 1, buffer->idx + 1);
}
/* Unsafe-to-break if end-of-text would kick in here. */
if (buffer->idx + 2 <= buffer->len)
{
const Entry<EntryData> *end_entry = machine.get_entryZ (state, 0);
if (c->is_actionable (this, end_entry))
buffer->unsafe_to_break (buffer->idx, buffer->idx + 2);
}
if (unlikely (!c->transition (this, entry)))
break;
last_was_dont_advance = (entry->flags & context_t::DontAdvance) && buffer->max_ops-- > 0;
state = entry->newState;
if (buffer->idx == buffer->len)
break;
if (!last_was_dont_advance)
buffer->next_glyph ();
}
if (!c->in_place)
{
for (; buffer->idx < buffer->len;)
buffer->next_glyph ();
buffer->swap_buffers ();
}
}
public:
const StateTable<EntryData> &machine;
hb_buffer_t *buffer;
unsigned int num_glyphs;
};
struct hb_aat_apply_context_t :
hb_dispatch_context_t<hb_aat_apply_context_t, bool, HB_DEBUG_APPLY>
{
inline const char *get_name (void) { return "APPLY"; }
template <typename T>
inline return_t dispatch (const T &obj) { return obj.apply (this); }
static return_t default_return_value (void) { return false; }
bool stop_sublookup_iteration (return_t r) const { return r; }
hb_font_t *font;
hb_face_t *face;
hb_buffer_t *buffer;
hb_sanitize_context_t sanitizer;
/* Unused. For debug tracing only. */
unsigned int lookup_index;
unsigned int debug_depth;
inline hb_aat_apply_context_t (hb_font_t *font_,
hb_buffer_t *buffer_,
hb_blob_t *table) :
font (font_), face (font->face), buffer (buffer_),
sanitizer (), lookup_index (0), debug_depth (0)
{
sanitizer.init (table);
sanitizer.set_num_glyphs (face->get_num_glyphs ());
sanitizer.start_processing ();
}
inline void set_lookup_index (unsigned int i) { lookup_index = i; }
inline ~hb_aat_apply_context_t (void)
{
sanitizer.end_processing ();
}
};
} /* namespace AAT */
#endif /* HB_AAT_LAYOUT_COMMON_HH */
