Update to Harfbuzz 2.6.4

Quite a big change since it has been several years since
the last update. This drops the Harfbuzz source on top
of the existing code in Qt, and does the following
additional changes:

1. Deletes old source files that have been removed upstream
(everything named foo-private.hh is now renamed to just
foo.hh for instance).

2. Added a header guard to config.h because it may be
double-included.

3. Implement a memory barrier needed by hb-atomic.hh.

4. Changed the signature of hb_atomic_int_impl_add()
to take a pointer to match new upstream.

5. Updated .pro file to include new files and removed
old.

6. Updated qt_attribution.json

7. No longer disable deprecated APIs since
hb_ot_tags_from_script() is now deprecated and is used
from Qt code.

8. Updated and applied the patch in patches/ for CoreText.

9. Updated tst_qtextscriptengine::thaiWithZWJ() according to
changes in Harfbuzz and disabled it for system-harfbuzz,
since this may be an older version of harfbuzz depending on
the system.

Fixes: QTBUG-79606
Change-Id: I3f057a43ff44ee416628b75ef12fb1a221f31910
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 841 insertions, 0 deletions

diff --git a/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-common.hh b/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-common.hh
new file mode 100644
index 0000000000..473f2cdcd2
--- /dev/null
+++ b/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-common.hh
@@ -0,0 +1,841 @@
+/*
+ * 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"
+#include "hb-open-type.hh"
+
+
+namespace AAT {
+
+using namespace OT;
+
+
+/*
+ * Lookup Table
+ */
+
+template <typename T> struct Lookup;
+
+template <typename T>
+struct LookupFormat0
+{
+  friend struct Lookup<T>;
+
+  private:
+  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];
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (arrayZ.sanitize (c, c->get_num_glyphs ()));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (arrayZ.sanitize (c, c->get_num_glyphs (), base));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 0 */
+  UnsizedArrayOf<T>
+		arrayZ;		/* Array of lookup values, indexed by glyph index. */
+  public:
+  DEFINE_SIZE_UNBOUNDED (2);
+};
+
+
+template <typename T>
+struct LookupSegmentSingle
+{
+  static constexpr unsigned TerminationWordCount = 2u;
+
+  int cmp (hb_codepoint_t g) const
+  { return g < first ? -1 : g <= last ? 0 : +1 ; }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && value.sanitize (c));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && value.sanitize (c, base));
+  }
+
+  HBGlyphID	last;		/* Last GlyphID in this segment */
+  HBGlyphID	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:
+  const T* get_value (hb_codepoint_t glyph_id) const
+  {
+    const LookupSegmentSingle<T> *v = segments.bsearch (glyph_id);
+    return v ? &v->value : nullptr;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (segments.sanitize (c));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (segments.sanitize (c, base));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 2 */
+  VarSizedBinSearchArrayOf<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
+{
+  static constexpr unsigned TerminationWordCount = 2u;
+
+  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;
+  }
+
+  int cmp (hb_codepoint_t g) const
+  { return g < first ? -1 : g <= last ? 0 : +1; }
+
+  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));
+  }
+  template <typename ...Ts>
+  bool sanitize (hb_sanitize_context_t *c, const void *base, Ts&&... ds) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  first <= last &&
+		  valuesZ.sanitize (c, base, last - first + 1, hb_forward<Ts> (ds)...));
+  }
+
+  HBGlyphID	last;		/* Last GlyphID in this segment */
+  HBGlyphID	first;		/* First GlyphID in this segment */
+  NNOffsetTo<UnsizedArrayOf<T>>
+		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:
+  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;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (segments.sanitize (c, this));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (segments.sanitize (c, this, base));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 4 */
+  VarSizedBinSearchArrayOf<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
+{
+  static constexpr unsigned TerminationWordCount = 1u;
+
+  int cmp (hb_codepoint_t g) const { return glyph.cmp (g); }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && value.sanitize (c));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && value.sanitize (c, base));
+  }
+
+  HBGlyphID	glyph;		/* Last GlyphID */
+  T		value;		/* The lookup value (only one) */
+  public:
+  DEFINE_SIZE_STATIC (2 + T::static_size);
+};
+
+template <typename T>
+struct LookupFormat6
+{
+  friend struct Lookup<T>;
+
+  private:
+  const T* get_value (hb_codepoint_t glyph_id) const
+  {
+    const LookupSingle<T> *v = entries.bsearch (glyph_id);
+    return v ? &v->value : nullptr;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (entries.sanitize (c));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (entries.sanitize (c, base));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 6 */
+  VarSizedBinSearchArrayOf<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:
+  const T* get_value (hb_codepoint_t glyph_id) const
+  {
+    return firstGlyph <= glyph_id && glyph_id - firstGlyph < glyphCount ?
+	   &valueArrayZ[glyph_id - firstGlyph] : nullptr;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && valueArrayZ.sanitize (c, glyphCount));
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && valueArrayZ.sanitize (c, glyphCount, base));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 8 */
+  HBGlyphID	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 LookupFormat10
+{
+  friend struct Lookup<T>;
+
+  private:
+  const typename T::type get_value_or_null (hb_codepoint_t glyph_id) const
+  {
+    if (!(firstGlyph <= glyph_id && glyph_id - firstGlyph < glyphCount))
+      return Null(T);
+
+    const HBUINT8 *p = &valueArrayZ[(glyph_id - firstGlyph) * valueSize];
+
+    unsigned int v = 0;
+    unsigned int count = valueSize;
+    for (unsigned int i = 0; i < count; i++)
+      v = (v << 8) | *p++;
+
+    return v;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  valueSize <= 4 &&
+		  valueArrayZ.sanitize (c, glyphCount * valueSize));
+  }
+
+  protected:
+  HBUINT16	format;		/* Format identifier--format = 8 */
+  HBUINT16	valueSize;	/* Byte size of each value. */
+  HBGlyphID	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<HBUINT8>
+		valueArrayZ;	/* The lookup values (indexed by the glyph index
+				 * minus the value of firstGlyph). */
+  public:
+  DEFINE_SIZE_ARRAY (8, valueArrayZ);
+};
+
+template <typename T>
+struct Lookup
+{
+  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;
+    }
+  }
+
+  const typename T::type get_value_or_null (hb_codepoint_t glyph_id, unsigned int num_glyphs) const
+  {
+    switch (u.format) {
+      /* Format 10 cannot return a pointer. */
+      case 10: return u.format10.get_value_or_null (glyph_id);
+      default:
+      const T *v = get_value (glyph_id, num_glyphs);
+      return v ? *v : Null(T);
+    }
+  }
+
+  typename T::type get_class (hb_codepoint_t glyph_id,
+			      unsigned int num_glyphs,
+			      unsigned int outOfRange) const
+  {
+    const T *v = get_value (glyph_id, num_glyphs);
+    return v ? *v : outOfRange;
+  }
+
+  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));
+    case 10: return_trace (u.format10.sanitize (c));
+    default:return_trace (true);
+    }
+  }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    if (!u.format.sanitize (c)) return_trace (false);
+    switch (u.format) {
+    case 0: return_trace (u.format0.sanitize (c, base));
+    case 2: return_trace (u.format2.sanitize (c, base));
+    case 4: return_trace (u.format4.sanitize (c, base));
+    case 6: return_trace (u.format6.sanitize (c, base));
+    case 8: return_trace (u.format8.sanitize (c, base));
+    case 10: return_trace (false); /* We don't support format10 here currently. */
+    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;
+  LookupFormat10<T>	format10;
+  } u;
+  public:
+  DEFINE_SIZE_UNION (2, format);
+};
+/* Lookup 0 has unbounded size (dependant on num_glyphs).  So we need to defined
+ * special NULL objects for Lookup<> objects, but since it's template our macros
+ * don't work.  So we have to hand-code them here.  UGLY. */
+} /* Close namespace. */
+/* Ugly hand-coded null objects for template Lookup<> :(. */
+extern HB_INTERNAL const unsigned char _hb_Null_AAT_Lookup[2];
+template <typename T>
+struct Null<AAT::Lookup<T>> {
+  static AAT::Lookup<T> const & get_null ()
+  { return *reinterpret_cast<const AAT::Lookup<T> *> (_hb_Null_AAT_Lookup); }
+};
+namespace AAT {
+
+enum { DELETED_GLYPH = 0xFFFF };
+
+/*
+ * (Extended) State Table
+ */
+
+template <typename T>
+struct Entry
+{
+  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.
+     *
+     * HOWEVER! Because we are a template, our DEFINE_SIZE_STATIC
+     * assertion wouldn't be checked, hence the line below. */
+    static_assert (T::static_size, "");
+
+    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>
+{
+  bool sanitize (hb_sanitize_context_t *c, unsigned int count /*XXX Unused?*/) 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 Types, typename Extra>
+struct StateTable
+{
+  typedef typename Types::HBUINT HBUINT;
+  typedef typename Types::HBUSHORT HBUSHORT;
+  typedef typename Types::ClassTypeNarrow ClassType;
+
+  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,
+  };
+
+  int new_state (unsigned int newState) const
+  { return Types::extended ? newState : ((int) newState - (int) stateArrayTable) / (int) nClasses; }
+
+  unsigned int get_class (hb_codepoint_t glyph_id, unsigned int num_glyphs) const
+  {
+    if (unlikely (glyph_id == DELETED_GLYPH)) return CLASS_DELETED_GLYPH;
+    return (this+classTable).get_class (glyph_id, num_glyphs, 1);
+  }
+
+  const Entry<Extra> *get_entries () const
+  { return (this+entryTable).arrayZ; }
+
+  const Entry<Extra> &get_entry (int state, unsigned int klass) const
+  {
+    if (unlikely (klass >= nClasses))
+      klass = StateTable<Types, Entry<Extra>>::CLASS_OUT_OF_BOUNDS;
+
+    const HBUSHORT *states = (this+stateArrayTable).arrayZ;
+    const Entry<Extra> *entries = (this+entryTable).arrayZ;
+
+    unsigned int entry = states[state * nClasses + klass];
+    DEBUG_MSG (APPLY, nullptr, "e%u", entry);
+
+    return entries[entry];
+  }
+
+  bool sanitize (hb_sanitize_context_t *c,
+		 unsigned int *num_entries_out = nullptr) const
+  {
+    TRACE_SANITIZE (this);
+    if (unlikely (!(c->check_struct (this) &&
+		    nClasses >= 4 /* Ensure pre-defined classes fit.  */ &&
+		    classTable.sanitize (c, this)))) return_trace (false);
+
+    const HBUSHORT *states = (this+stateArrayTable).arrayZ;
+    const Entry<Extra> *entries = (this+entryTable).arrayZ;
+
+    unsigned int num_classes = nClasses;
+    if (unlikely (hb_unsigned_mul_overflows (num_classes, states[0].static_size)))
+      return_trace (false);
+    unsigned int row_stride = num_classes * states[0].static_size;
+
+    /* Apple 'kern' table has this peculiarity:
+     *
+     * "Because the stateTableOffset in the state table header is (strictly
+     * speaking) redundant, some 'kern' tables use it to record an initial
+     * state where that should not be StartOfText. To determine if this is
+     * done, calculate what the stateTableOffset should be. If it's different
+     * from the actual stateTableOffset, use it as the initial state."
+     *
+     * We implement this by calling the initial state zero, but allow *negative*
+     * states if the start state indeed was not the first state.  Since the code
+     * is shared, this will also apply to 'mort' table.  The 'kerx' / 'morx'
+     * tables are not affected since those address states by index, not offset.
+     */
+
+    int min_state = 0;
+    int max_state = 0;
+    unsigned int num_entries = 0;
+
+    int state_pos = 0;
+    int state_neg = 0;
+    unsigned int entry = 0;
+    while (min_state < state_neg || state_pos <= max_state)
+    {
+      if (min_state < state_neg)
+      {
+	/* Negative states. */
+	if (unlikely (hb_unsigned_mul_overflows (min_state, num_classes)))
+	  return_trace (false);
+	if (unlikely (!c->check_range (&states[min_state * num_classes],
+				       -min_state,
+				       row_stride)))
+	  return_trace (false);
+	if ((c->max_ops -= state_neg - min_state) <= 0)
+	  return_trace (false);
+	{ /* Sweep new states. */
+	  const HBUSHORT *stop = &states[min_state * num_classes];
+	  if (unlikely (stop > states))
+	    return_trace (false);
+	  for (const HBUSHORT *p = states; stop < p; p--)
+	    num_entries = hb_max (num_entries, *(p - 1) + 1);
+	  state_neg = min_state;
+	}
+      }
+
+      if (state_pos <= max_state)
+      {
+	/* Positive states. */
+	if (unlikely (!c->check_range (states,
+				       max_state + 1,
+				       row_stride)))
+	  return_trace (false);
+	if ((c->max_ops -= max_state - state_pos + 1) <= 0)
+	  return_trace (false);
+	{ /* Sweep new states. */
+	  if (unlikely (hb_unsigned_mul_overflows ((max_state + 1), num_classes)))
+	    return_trace (false);
+	  const HBUSHORT *stop = &states[(max_state + 1) * num_classes];
+	  if (unlikely (stop < states))
+	    return_trace (false);
+	  for (const HBUSHORT *p = &states[state_pos * num_classes]; p < stop; p++)
+	    num_entries = hb_max (num_entries, *p + 1);
+	  state_pos = max_state + 1;
+	}
+      }
+
+      if (unlikely (!c->check_array (entries, num_entries)))
+	return_trace (false);
+      if ((c->max_ops -= num_entries - entry) <= 0)
+	return_trace (false);
+      { /* Sweep new entries. */
+	const Entry<Extra> *stop = &entries[num_entries];
+	for (const Entry<Extra> *p = &entries[entry]; p < stop; p++)
+	{
+	  int newState = new_state (p->newState);
+	  min_state = hb_min (min_state, newState);
+	  max_state = hb_max (max_state, newState);
+	}
+	entry = num_entries;
+      }
+    }
+
+    if (num_entries_out)
+      *num_entries_out = num_entries;
+
+    return_trace (true);
+  }
+
+  protected:
+  HBUINT	nClasses;	/* Number of classes, which is the number of indices
+				 * in a single line in the state array. */
+  NNOffsetTo<ClassType, HBUINT>
+		classTable;	/* Offset to the class table. */
+  NNOffsetTo<UnsizedArrayOf<HBUSHORT>, HBUINT>
+		stateArrayTable;/* Offset to the state array. */
+  NNOffsetTo<UnsizedArrayOf<Entry<Extra>>, HBUINT>
+		entryTable;	/* Offset to the entry array. */
+
+  public:
+  DEFINE_SIZE_STATIC (4 * sizeof (HBUINT));
+};
+
+template <typename HBUCHAR>
+struct ClassTable
+{
+  unsigned int get_class (hb_codepoint_t glyph_id, unsigned int outOfRange) const
+  {
+    unsigned int i = glyph_id - firstGlyph;
+    return i >= classArray.len ? outOfRange : classArray.arrayZ[i];
+  }
+  unsigned int get_class (hb_codepoint_t glyph_id,
+			  unsigned int num_glyphs HB_UNUSED,
+			  unsigned int outOfRange) const
+  {
+    return get_class (glyph_id, outOfRange);
+  }
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && classArray.sanitize (c));
+  }
+  protected:
+  HBGlyphID		firstGlyph;	/* First glyph index included in the trimmed array. */
+  ArrayOf<HBUCHAR>	classArray;	/* The class codes (indexed by glyph index minus
+					 * firstGlyph). */
+  public:
+  DEFINE_SIZE_ARRAY (4, classArray);
+};
+
+struct ObsoleteTypes
+{
+  static constexpr bool extended = false;
+  typedef HBUINT16 HBUINT;
+  typedef HBUINT8 HBUSHORT;
+  typedef ClassTable<HBUINT8> ClassTypeNarrow;
+  typedef ClassTable<HBUINT16> ClassTypeWide;
+
+  template <typename T>
+  static unsigned int offsetToIndex (unsigned int offset,
+				     const void *base,
+				     const T *array)
+  {
+    return (offset - ((const char *) array - (const char *) base)) / T::static_size;
+  }
+  template <typename T>
+  static unsigned int byteOffsetToIndex (unsigned int offset,
+					 const void *base,
+					 const T *array)
+  {
+    return offsetToIndex (offset, base, array);
+  }
+  template <typename T>
+  static unsigned int wordOffsetToIndex (unsigned int offset,
+					 const void *base,
+					 const T *array)
+  {
+    return offsetToIndex (2 * offset, base, array);
+  }
+};
+struct ExtendedTypes
+{
+  static constexpr bool extended = true;
+  typedef HBUINT32 HBUINT;
+  typedef HBUINT16 HBUSHORT;
+  typedef Lookup<HBUINT16> ClassTypeNarrow;
+  typedef Lookup<HBUINT16> ClassTypeWide;
+
+  template <typename T>
+  static unsigned int offsetToIndex (unsigned int offset,
+				     const void *base HB_UNUSED,
+				     const T *array HB_UNUSED)
+  {
+    return offset;
+  }
+  template <typename T>
+  static unsigned int byteOffsetToIndex (unsigned int offset,
+					 const void *base HB_UNUSED,
+					 const T *array HB_UNUSED)
+  {
+    return offset / 2;
+  }
+  template <typename T>
+  static unsigned int wordOffsetToIndex (unsigned int offset,
+					 const void *base HB_UNUSED,
+					 const T *array HB_UNUSED)
+  {
+    return offset;
+  }
+};
+
+template <typename Types, typename EntryData>
+struct StateTableDriver
+{
+  StateTableDriver (const StateTable<Types, EntryData> &machine_,
+		    hb_buffer_t *buffer_,
+		    hb_face_t *face_) :
+	      machine (machine_),
+	      buffer (buffer_),
+	      num_glyphs (face_->get_num_glyphs ()) {}
+
+  template <typename context_t>
+  void drive (context_t *c)
+  {
+    if (!c->in_place)
+      buffer->clear_output ();
+
+    int state = StateTable<Types, EntryData>::STATE_START_OF_TEXT;
+    for (buffer->idx = 0; buffer->successful;)
+    {
+      unsigned int klass = buffer->idx < buffer->len ?
+			   machine.get_class (buffer->info[buffer->idx].codepoint, num_glyphs) :
+			   (unsigned) StateTable<Types, EntryData>::CLASS_END_OF_TEXT;
+      DEBUG_MSG (APPLY, nullptr, "c%u at %u", klass, buffer->idx);
+      const Entry<EntryData> &entry = machine.get_entry (state, klass);
+
+      /* Unsafe-to-break before this if not in state 0, as things might
+       * go differently if we start from state 0 here.
+       *
+       * Ugh.  The indexing here is ugly... */
+      if (state && buffer->backtrack_len () && buffer->idx < buffer->len)
+      {
+	/* 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<Types, EntryData>::STATE_START_OF_TEXT &&
+	      entry.flags == context_t::DontAdvance))
+	  buffer->unsafe_to_break_from_outbuffer (buffer->backtrack_len () - 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_entry (state, StateTable<Types, EntryData>::CLASS_END_OF_TEXT);
+	if (c->is_actionable (this, end_entry))
+	  buffer->unsafe_to_break (buffer->idx, buffer->idx + 2);
+      }
+
+      c->transition (this, entry);
+
+      state = machine.new_state (entry.newState);
+      DEBUG_MSG (APPLY, nullptr, "s%d", state);
+
+      if (buffer->idx == buffer->len)
+	break;
+
+      if (!(entry.flags & context_t::DontAdvance) || buffer->max_ops-- <= 0)
+	buffer->next_glyph ();
+    }
+
+    if (!c->in_place)
+    {
+      for (; buffer->successful && buffer->idx < buffer->len;)
+	buffer->next_glyph ();
+      buffer->swap_buffers ();
+    }
+  }
+
+  public:
+  const StateTable<Types, EntryData> &machine;
+  hb_buffer_t *buffer;
+  unsigned int num_glyphs;
+};
+
+
+struct ankr;
+
+struct hb_aat_apply_context_t :
+       hb_dispatch_context_t<hb_aat_apply_context_t, bool, HB_DEBUG_APPLY>
+{
+  const char *get_name () { return "APPLY"; }
+  template <typename T>
+  return_t dispatch (const T &obj) { return obj.apply (this); }
+  static return_t default_return_value () { return false; }
+  bool stop_sublookup_iteration (return_t r) const { return r; }
+
+  const hb_ot_shape_plan_t *plan;
+  hb_font_t *font;
+  hb_face_t *face;
+  hb_buffer_t *buffer;
+  hb_sanitize_context_t sanitizer;
+  const ankr *ankr_table;
+
+  /* Unused. For debug tracing only. */
+  unsigned int lookup_index;
+  unsigned int debug_depth;
+
+  HB_INTERNAL hb_aat_apply_context_t (const hb_ot_shape_plan_t *plan_,
+				      hb_font_t *font_,
+				      hb_buffer_t *buffer_,
+				      hb_blob_t *blob = const_cast<hb_blob_t *> (&Null(hb_blob_t)));
+
+  HB_INTERNAL ~hb_aat_apply_context_t ();
+
+  HB_INTERNAL void set_ankr_table (const AAT::ankr *ankr_table_);
+
+  void set_lookup_index (unsigned int i) { lookup_index = i; }
+};
+
+
+} /* namespace AAT */
+
+
+#endif /* HB_AAT_LAYOUT_COMMON_HH */