1 files changed, 35 insertions, 1306 deletions

diff --git a/src/3rdparty/harfbuzz-ng/src/hb-ot-layout-gsub-table.hh b/src/3rdparty/harfbuzz-ng/src/hb-ot-layout-gsub-table.hh
index 0b09c4e4a1..fd8a68be02 100644
--- a/src/3rdparty/harfbuzz-ng/src/hb-ot-layout-gsub-table.hh
+++ b/src/3rdparty/harfbuzz-ng/src/hb-ot-layout-gsub-table.hh
@@ -29,1336 +29,65 @@
 #ifndef HB_OT_LAYOUT_GSUB_TABLE_HH
 #define HB_OT_LAYOUT_GSUB_TABLE_HH
 
-#include "hb-ot-layout-gsubgpos-private.hh"
-
+#include "OT/Layout/GSUB/GSUB.hh"
 
 namespace OT {
+namespace Layout {
+namespace GSUB_impl {
 
+// TODO(garretrieger): Move into the new layout directory.
+/* Out-of-class implementation for methods recursing */
 
-struct SingleSubstFormat1
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    Coverage::Iter iter;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      /* TODO Switch to range-based API to work around malicious fonts.
-       * https://github.com/harfbuzz/harfbuzz/issues/363 */
-      hb_codepoint_t glyph_id = iter.get_glyph ();
-      if (c->glyphs->has (glyph_id))
-	c->glyphs->add ((glyph_id + deltaGlyphID) & 0xFFFFu);
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-    Coverage::Iter iter;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      /* TODO Switch to range-based API to work around malicious fonts.
-       * https://github.com/harfbuzz/harfbuzz/issues/363 */
-      hb_codepoint_t glyph_id = iter.get_glyph ();
-      c->output->add ((glyph_id + deltaGlyphID) & 0xFFFFu);
-    }
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    return_trace (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
-    unsigned int index = (this+coverage).get_coverage (glyph_id);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    /* According to the Adobe Annotated OpenType Suite, result is always
-     * limited to 16bit. */
-    glyph_id = (glyph_id + deltaGlyphID) & 0xFFFFu;
-    c->replace_glyph (glyph_id);
-
-    return_trace (true);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 unsigned int num_glyphs,
-			 int delta)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return_trace (false);
-    deltaGlyphID.set (delta); /* TODO(serilaize) overflow? */
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 1 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of Substitution table */
-  INT16		deltaGlyphID;		/* Add to original GlyphID to get
-					 * substitute GlyphID */
-  public:
-  DEFINE_SIZE_STATIC (6);
-};
-
-struct SingleSubstFormat2
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    Coverage::Iter iter;
-    unsigned int count = substitute.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      if (c->glyphs->has (iter.get_glyph ()))
-	c->glyphs->add (substitute[iter.get_coverage ()]);
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-    Coverage::Iter iter;
-    unsigned int count = substitute.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      c->output->add (substitute[iter.get_coverage ()]);
-    }
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    return_trace (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
-    unsigned int index = (this+coverage).get_coverage (glyph_id);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    if (unlikely (index >= substitute.len)) return_trace (false);
-
-    glyph_id = substitute[index];
-    c->replace_glyph (glyph_id);
-
-    return_trace (true);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<GlyphID> &substitutes,
-			 unsigned int num_glyphs)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!substitute.serialize (c, substitutes, num_glyphs))) return_trace (false);
-    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return_trace (false);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (coverage.sanitize (c, this) && substitute.sanitize (c));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 2 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of Substitution table */
-  ArrayOf<GlyphID>
-		substitute;		/* Array of substitute
-					 * GlyphIDs--ordered by Coverage Index */
-  public:
-  DEFINE_SIZE_ARRAY (6, substitute);
-};
-
-struct SingleSubst
-{
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<GlyphID> &substitutes,
-			 unsigned int num_glyphs)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (u.format))) return_trace (false);
-    unsigned int format = 2;
-    int delta = 0;
-    if (num_glyphs) {
-      format = 1;
-      /* TODO(serialize) check for wrap-around */
-      delta = substitutes[0] - glyphs[0];
-      for (unsigned int i = 1; i < num_glyphs; i++)
-	if (delta != substitutes[i] - glyphs[i]) {
-	  format = 2;
-	  break;
-	}
-    }
-    u.format.set (format);
-    switch (u.format) {
-    case 1: return_trace (u.format1.serialize (c, glyphs, num_glyphs, delta));
-    case 2: return_trace (u.format2.serialize (c, glyphs, substitutes, num_glyphs));
-    default:return_trace (false);
-    }
-  }
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  {
-    TRACE_DISPATCH (this, u.format);
-    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
-    switch (u.format) {
-    case 1: return_trace (c->dispatch (u.format1));
-    case 2: return_trace (c->dispatch (u.format2));
-    default:return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16		format;		/* Format identifier */
-  SingleSubstFormat1	format1;
-  SingleSubstFormat2	format2;
-  } u;
-};
-
-
-struct Sequence
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    unsigned int count = substitute.len;
-    for (unsigned int i = 0; i < count; i++)
-      c->glyphs->add (substitute[i]);
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    c->output->add_array (substitute.array, substitute.len);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    unsigned int count = substitute.len;
-
-    /* Special-case to make it in-place and not consider this
-     * as a "multiplied" substitution. */
-    if (unlikely (count == 1))
-    {
-      c->replace_glyph (substitute.array[0]);
-      return_trace (true);
-    }
-    /* Spec disallows this, but Uniscribe allows it.
-     * https://github.com/harfbuzz/harfbuzz/issues/253 */
-    else if (unlikely (count == 0))
-    {
-      c->buffer->delete_glyph ();
-      return_trace (true);
-    }
-
-    unsigned int klass = _hb_glyph_info_is_ligature (&c->buffer->cur()) ?
-			 HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH : 0;
-
-    for (unsigned int i = 0; i < count; i++) {
-      _hb_glyph_info_set_lig_props_for_component (&c->buffer->cur(), i);
-      c->output_glyph_for_component (substitute.array[i], klass);
-    }
-    c->buffer->skip_glyph ();
-
-    return_trace (true);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 unsigned int num_glyphs)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!substitute.serialize (c, glyphs, num_glyphs))) return_trace (false);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (substitute.sanitize (c));
-  }
-
-  protected:
-  ArrayOf<GlyphID>
-		substitute;		/* String of GlyphIDs to substitute */
-  public:
-  DEFINE_SIZE_ARRAY (2, substitute);
-};
-
-struct MultipleSubstFormat1
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    Coverage::Iter iter;
-    unsigned int count = sequence.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      if (c->glyphs->has (iter.get_glyph ()))
-	(this+sequence[iter.get_coverage ()]).closure (c);
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-    unsigned int count = sequence.len;
-    for (unsigned int i = 0; i < count; i++)
-	(this+sequence[i]).collect_glyphs (c);
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    return_trace (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-
-    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    return_trace ((this+sequence[index]).apply (c));
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<unsigned int> &substitute_len_list,
-			 unsigned int num_glyphs,
-			 Supplier<GlyphID> &substitute_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!sequence.serialize (c, num_glyphs))) return_trace (false);
-    for (unsigned int i = 0; i < num_glyphs; i++)
-      if (unlikely (!sequence[i].serialize (c, this).serialize (c,
-								substitute_glyphs_list,
-								substitute_len_list[i]))) return_trace (false);
-    substitute_len_list.advance (num_glyphs);
-    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return_trace (false);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (coverage.sanitize (c, this) && sequence.sanitize (c, this));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 1 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of Substitution table */
-  OffsetArrayOf<Sequence>
-		sequence;		/* Array of Sequence tables
-					 * ordered by Coverage Index */
-  public:
-  DEFINE_SIZE_ARRAY (6, sequence);
-};
-
-struct MultipleSubst
-{
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<unsigned int> &substitute_len_list,
-			 unsigned int num_glyphs,
-			 Supplier<GlyphID> &substitute_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (u.format))) return_trace (false);
-    unsigned int format = 1;
-    u.format.set (format);
-    switch (u.format) {
-    case 1: return_trace (u.format1.serialize (c, glyphs, substitute_len_list, num_glyphs, substitute_glyphs_list));
-    default:return_trace (false);
-    }
-  }
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  {
-    TRACE_DISPATCH (this, u.format);
-    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
-    switch (u.format) {
-    case 1: return_trace (c->dispatch (u.format1));
-    default:return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16		format;		/* Format identifier */
-  MultipleSubstFormat1	format1;
-  } u;
-};
-
-
-typedef ArrayOf<GlyphID> AlternateSet;	/* Array of alternate GlyphIDs--in
-					 * arbitrary order */
-
-struct AlternateSubstFormat1
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    Coverage::Iter iter;
-    unsigned int count = alternateSet.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      if (c->glyphs->has (iter.get_glyph ())) {
-	const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()];
-	unsigned int count = alt_set.len;
-	for (unsigned int i = 0; i < count; i++)
-	  c->glyphs->add (alt_set[i]);
-      }
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-    Coverage::Iter iter;
-    unsigned int count = alternateSet.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()];
-      c->output->add_array (alt_set.array, alt_set.len);
-    }
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    return_trace (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
-
-    unsigned int index = (this+coverage).get_coverage (glyph_id);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    const AlternateSet &alt_set = this+alternateSet[index];
-
-    if (unlikely (!alt_set.len)) return_trace (false);
-
-    hb_mask_t glyph_mask = c->buffer->cur().mask;
-    hb_mask_t lookup_mask = c->lookup_mask;
-
-    /* Note: This breaks badly if two features enabled this lookup together. */
-    unsigned int shift = _hb_ctz (lookup_mask);
-    unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift);
-
-    if (unlikely (alt_index > alt_set.len || alt_index == 0)) return_trace (false);
-
-    glyph_id = alt_set[alt_index - 1];
-
-    c->replace_glyph (glyph_id);
-
-    return_trace (true);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<unsigned int> &alternate_len_list,
-			 unsigned int num_glyphs,
-			 Supplier<GlyphID> &alternate_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!alternateSet.serialize (c, num_glyphs))) return_trace (false);
-    for (unsigned int i = 0; i < num_glyphs; i++)
-      if (unlikely (!alternateSet[i].serialize (c, this).serialize (c,
-								    alternate_glyphs_list,
-								    alternate_len_list[i]))) return_trace (false);
-    alternate_len_list.advance (num_glyphs);
-    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return_trace (false);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 1 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of Substitution table */
-  OffsetArrayOf<AlternateSet>
-		alternateSet;		/* Array of AlternateSet tables
-					 * ordered by Coverage Index */
-  public:
-  DEFINE_SIZE_ARRAY (6, alternateSet);
-};
-
-struct AlternateSubst
-{
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &glyphs,
-			 Supplier<unsigned int> &alternate_len_list,
-			 unsigned int num_glyphs,
-			 Supplier<GlyphID> &alternate_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (u.format))) return_trace (false);
-    unsigned int format = 1;
-    u.format.set (format);
-    switch (u.format) {
-    case 1: return_trace (u.format1.serialize (c, glyphs, alternate_len_list, num_glyphs, alternate_glyphs_list));
-    default:return_trace (false);
-    }
-  }
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  {
-    TRACE_DISPATCH (this, u.format);
-    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
-    switch (u.format) {
-    case 1: return_trace (c->dispatch (u.format1));
-    default:return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16		format;		/* Format identifier */
-  AlternateSubstFormat1	format1;
-  } u;
-};
-
-
-struct Ligature
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    unsigned int count = component.len;
-    for (unsigned int i = 1; i < count; i++)
-      if (!c->glyphs->has (component[i]))
-        return;
-    c->glyphs->add (ligGlyph);
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    c->input->add_array (component.array, component.len ? component.len - 1 : 0);
-    c->output->add (ligGlyph);
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    if (c->len != component.len)
-      return_trace (false);
-
-    for (unsigned int i = 1; i < c->len; i++)
-      if (likely (c->glyphs[i] != component[i]))
-	return_trace (false);
-
-    return_trace (true);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    unsigned int count = component.len;
-
-    if (unlikely (!count)) return_trace (false);
-
-    /* Special-case to make it in-place and not consider this
-     * as a "ligated" substitution. */
-    if (unlikely (count == 1))
-    {
-      c->replace_glyph (ligGlyph);
-      return_trace (true);
-    }
-
-    bool is_mark_ligature = false;
-    unsigned int total_component_count = 0;
-
-    unsigned int match_length = 0;
-    unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
-
-    if (likely (!match_input (c, count,
-			      &component[1],
-			      match_glyph,
-			      nullptr,
-			      &match_length,
-			      match_positions,
-			      &is_mark_ligature,
-			      &total_component_count)))
-      return_trace (false);
-
-    ligate_input (c,
-		  count,
-		  match_positions,
-		  match_length,
-		  ligGlyph,
-		  is_mark_ligature,
-		  total_component_count);
-
-    return_trace (true);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 GlyphID ligature,
-			 Supplier<GlyphID> &components, /* Starting from second */
-			 unsigned int num_components /* Including first component */)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    ligGlyph = ligature;
-    if (unlikely (!component.serialize (c, components, num_components))) return_trace (false);
-    return_trace (true);
-  }
-
-  public:
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (ligGlyph.sanitize (c) && component.sanitize (c));
-  }
-
-  protected:
-  GlyphID	ligGlyph;		/* GlyphID of ligature to substitute */
-  HeadlessArrayOf<GlyphID>
-		component;		/* Array of component GlyphIDs--start
-					 * with the second  component--ordered
-					 * in writing direction */
-  public:
-  DEFINE_SIZE_ARRAY (4, component);
-};
-
-struct LigatureSet
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    unsigned int num_ligs = ligature.len;
-    for (unsigned int i = 0; i < num_ligs; i++)
-      (this+ligature[i]).closure (c);
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    unsigned int num_ligs = ligature.len;
-    for (unsigned int i = 0; i < num_ligs; i++)
-      (this+ligature[i]).collect_glyphs (c);
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    unsigned int num_ligs = ligature.len;
-    for (unsigned int i = 0; i < num_ligs; i++)
-    {
-      const Ligature &lig = this+ligature[i];
-      if (lig.would_apply (c))
-        return_trace (true);
-    }
-    return_trace (false);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    unsigned int num_ligs = ligature.len;
-    for (unsigned int i = 0; i < num_ligs; i++)
-    {
-      const Ligature &lig = this+ligature[i];
-      if (lig.apply (c)) return_trace (true);
-    }
-
-    return_trace (false);
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &ligatures,
-			 Supplier<unsigned int> &component_count_list,
-			 unsigned int num_ligatures,
-			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!ligature.serialize (c, num_ligatures))) return_trace (false);
-    for (unsigned int i = 0; i < num_ligatures; i++)
-      if (unlikely (!ligature[i].serialize (c, this).serialize (c,
-								ligatures[i],
-								component_list,
-								component_count_list[i]))) return_trace (false);
-    ligatures.advance (num_ligatures);
-    component_count_list.advance (num_ligatures);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (ligature.sanitize (c, this));
-  }
-
-  protected:
-  OffsetArrayOf<Ligature>
-		ligature;		/* Array LigatureSet tables
-					 * ordered by preference */
-  public:
-  DEFINE_SIZE_ARRAY (2, ligature);
-};
-
-struct LigatureSubstFormat1
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    Coverage::Iter iter;
-    unsigned int count = ligatureSet.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      if (c->glyphs->has (iter.get_glyph ()))
-	(this+ligatureSet[iter.get_coverage ()]).closure (c);
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-    Coverage::Iter iter;
-    unsigned int count = ligatureSet.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      (this+ligatureSet[iter.get_coverage ()]).collect_glyphs (c);
-    }
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    unsigned int index = (this+coverage).get_coverage (c->glyphs[0]);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    const LigatureSet &lig_set = this+ligatureSet[index];
-    return_trace (lig_set.would_apply (c));
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
-
-    unsigned int index = (this+coverage).get_coverage (glyph_id);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    const LigatureSet &lig_set = this+ligatureSet[index];
-    return_trace (lig_set.apply (c));
-  }
-
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &first_glyphs,
-			 Supplier<unsigned int> &ligature_per_first_glyph_count_list,
-			 unsigned int num_first_glyphs,
-			 Supplier<GlyphID> &ligatures_list,
-			 Supplier<unsigned int> &component_count_list,
-			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (*this))) return_trace (false);
-    if (unlikely (!ligatureSet.serialize (c, num_first_glyphs))) return_trace (false);
-    for (unsigned int i = 0; i < num_first_glyphs; i++)
-      if (unlikely (!ligatureSet[i].serialize (c, this).serialize (c,
-								   ligatures_list,
-								   component_count_list,
-								   ligature_per_first_glyph_count_list[i],
-								   component_list))) return_trace (false);
-    ligature_per_first_glyph_count_list.advance (num_first_glyphs);
-    if (unlikely (!coverage.serialize (c, this).serialize (c, first_glyphs, num_first_glyphs))) return_trace (false);
-    return_trace (true);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 1 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of Substitution table */
-  OffsetArrayOf<LigatureSet>
-		ligatureSet;		/* Array LigatureSet tables
-					 * ordered by Coverage Index */
-  public:
-  DEFINE_SIZE_ARRAY (6, ligatureSet);
-};
-
-struct LigatureSubst
-{
-  inline bool serialize (hb_serialize_context_t *c,
-			 Supplier<GlyphID> &first_glyphs,
-			 Supplier<unsigned int> &ligature_per_first_glyph_count_list,
-			 unsigned int num_first_glyphs,
-			 Supplier<GlyphID> &ligatures_list,
-			 Supplier<unsigned int> &component_count_list,
-			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!c->extend_min (u.format))) return_trace (false);
-    unsigned int format = 1;
-    u.format.set (format);
-    switch (u.format) {
-    case 1: return_trace (u.format1.serialize (c,
-					       first_glyphs,
-					       ligature_per_first_glyph_count_list,
-					       num_first_glyphs,
-					       ligatures_list,
-					       component_count_list,
-					       component_list));
-    default:return_trace (false);
-    }
-  }
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  {
-    TRACE_DISPATCH (this, u.format);
-    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
-    switch (u.format) {
-    case 1: return_trace (c->dispatch (u.format1));
-    default:return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16		format;		/* Format identifier */
-  LigatureSubstFormat1	format1;
-  } u;
-};
-
-
-struct ContextSubst : Context {};
-
-struct ChainContextSubst : ChainContext {};
-
-struct ExtensionSubst : Extension<ExtensionSubst>
-{
-  typedef struct SubstLookupSubTable LookupSubTable;
-
-  inline bool is_reverse (void) const;
-};
-
-
-struct ReverseChainSingleSubstFormat1
-{
-  inline void closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
-
-    unsigned int count;
-
-    count = backtrack.len;
-    for (unsigned int i = 0; i < count; i++)
-      if (!(this+backtrack[i]).intersects (c->glyphs))
-        return;
-
-    count = lookahead.len;
-    for (unsigned int i = 0; i < count; i++)
-      if (!(this+lookahead[i]).intersects (c->glyphs))
-        return;
-
-    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
-    Coverage::Iter iter;
-    count = substitute.len;
-    for (iter.init (this+coverage); iter.more (); iter.next ())
-    {
-      if (unlikely (iter.get_coverage () >= count))
-        break; /* Work around malicious fonts. https://github.com/harfbuzz/harfbuzz/issues/363 */
-      if (c->glyphs->has (iter.get_glyph ()))
-	c->glyphs->add (substitute[iter.get_coverage ()]);
-    }
-  }
-
-  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    if (unlikely (!(this+coverage).add_coverage (c->input))) return;
-
-    unsigned int count;
-
-    count = backtrack.len;
-    for (unsigned int i = 0; i < count; i++)
-      if (unlikely (!(this+backtrack[i]).add_coverage (c->before))) return;
-
-    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
-    count = lookahead.len;
-    for (unsigned int i = 0; i < count; i++)
-      if (unlikely (!(this+lookahead[i]).add_coverage (c->after))) return;
-
-    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
-    count = substitute.len;
-    c->output->add_array (substitute.array, substitute.len);
-  }
-
-  inline const Coverage &get_coverage (void) const
-  {
-    return this+coverage;
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    TRACE_WOULD_APPLY (this);
-    return_trace (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
-      return_trace (false); /* No chaining to this type */
-
-    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
-    if (likely (index == NOT_COVERED)) return_trace (false);
-
-    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
-    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
-
-  unsigned int start_index = 0, end_index = 0;
-    if (match_backtrack (c,
-			 backtrack.len, (UINT16 *) backtrack.array,
-			 match_coverage, this,
-			 &start_index) &&
-        match_lookahead (c,
-			 lookahead.len, (UINT16 *) lookahead.array,
-			 match_coverage, this,
-			 1, &end_index))
-    {
-      c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);
-      c->replace_glyph_inplace (substitute[index]);
-      /* Note: We DON'T decrease buffer->idx.  The main loop does it
-       * for us.  This is useful for preventing surprises if someone
-       * calls us through a Context lookup. */
-      return_trace (true);
-    }
-
-    return_trace (false);
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
-      return_trace (false);
-    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
-    if (!lookahead.sanitize (c, this))
-      return_trace (false);
-    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
-    return_trace (substitute.sanitize (c));
-  }
-
-  protected:
-  UINT16	format;			/* Format identifier--format = 1 */
-  OffsetTo<Coverage>
-		coverage;		/* Offset to Coverage table--from
-					 * beginning of table */
-  OffsetArrayOf<Coverage>
-		backtrack;		/* Array of coverage tables
-					 * in backtracking sequence, in  glyph
-					 * sequence order */
-  OffsetArrayOf<Coverage>
-		lookaheadX;		/* Array of coverage tables
-					 * in lookahead sequence, in glyph
-					 * sequence order */
-  ArrayOf<GlyphID>
-		substituteX;		/* Array of substitute
-					 * GlyphIDs--ordered by Coverage Index */
-  public:
-  DEFINE_SIZE_MIN (10);
-};
-
-struct ReverseChainSingleSubst
-{
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  {
-    TRACE_DISPATCH (this, u.format);
-    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
-    switch (u.format) {
-    case 1: return_trace (c->dispatch (u.format1));
-    default:return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16				format;		/* Format identifier */
-  ReverseChainSingleSubstFormat1	format1;
-  } u;
-};
-
-
-
-/*
- * SubstLookup
- */
-
-struct SubstLookupSubTable
-{
-  friend struct SubstLookup;
-
-  enum Type {
-    Single		= 1,
-    Multiple		= 2,
-    Alternate		= 3,
-    Ligature		= 4,
-    Context		= 5,
-    ChainContext	= 6,
-    Extension		= 7,
-    ReverseChainSingle	= 8
-  };
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type) const
-  {
-    TRACE_DISPATCH (this, lookup_type);
-    if (unlikely (!c->may_dispatch (this, &u.sub_format))) return_trace (c->no_dispatch_return_value ());
-    switch (lookup_type) {
-    case Single:		return_trace (u.single.dispatch (c));
-    case Multiple:		return_trace (u.multiple.dispatch (c));
-    case Alternate:		return_trace (u.alternate.dispatch (c));
-    case Ligature:		return_trace (u.ligature.dispatch (c));
-    case Context:		return_trace (u.context.dispatch (c));
-    case ChainContext:		return_trace (u.chainContext.dispatch (c));
-    case Extension:		return_trace (u.extension.dispatch (c));
-    case ReverseChainSingle:	return_trace (u.reverseChainContextSingle.dispatch (c));
-    default:			return_trace (c->default_return_value ());
-    }
-  }
-
-  protected:
-  union {
-  UINT16			sub_format;
-  SingleSubst			single;
-  MultipleSubst			multiple;
-  AlternateSubst		alternate;
-  LigatureSubst			ligature;
-  ContextSubst			context;
-  ChainContextSubst		chainContext;
-  ExtensionSubst		extension;
-  ReverseChainSingleSubst	reverseChainContextSingle;
-  } u;
-  public:
-  DEFINE_SIZE_UNION (2, sub_format);
-};
-
-
-struct SubstLookup : Lookup
-{
-  inline const SubstLookupSubTable& get_subtable (unsigned int i) const
-  { return Lookup::get_subtable<SubstLookupSubTable> (i); }
-
-  inline static bool lookup_type_is_reverse (unsigned int lookup_type)
-  { return lookup_type == SubstLookupSubTable::ReverseChainSingle; }
-
-  inline bool is_reverse (void) const
-  {
-    unsigned int type = get_type ();
-    if (unlikely (type == SubstLookupSubTable::Extension))
-      return CastR<ExtensionSubst> (get_subtable(0)).is_reverse ();
-    return lookup_type_is_reverse (type);
-  }
-
-  inline bool apply (hb_apply_context_t *c) const
-  {
-    TRACE_APPLY (this);
-    return_trace (dispatch (c));
-  }
-
-  inline hb_closure_context_t::return_t closure (hb_closure_context_t *c) const
-  {
-    TRACE_CLOSURE (this);
-    c->set_recurse_func (dispatch_recurse_func<hb_closure_context_t>);
-    return_trace (dispatch (c));
-  }
-
-  inline hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
-  {
-    TRACE_COLLECT_GLYPHS (this);
-    c->set_recurse_func (dispatch_recurse_func<hb_collect_glyphs_context_t>);
-    return_trace (dispatch (c));
-  }
-
-  template <typename set_t>
-  inline void add_coverage (set_t *glyphs) const
-  {
-    hb_add_coverage_context_t<set_t> c (glyphs);
-    dispatch (&c);
-  }
-
-  inline bool would_apply (hb_would_apply_context_t *c,
-			   const hb_ot_layout_lookup_accelerator_t *accel) const
-  {
-    TRACE_WOULD_APPLY (this);
-    if (unlikely (!c->len))  return_trace (false);
-    if (!accel->may_have (c->glyphs[0]))  return_trace (false);
-      return_trace (dispatch (c));
-  }
-
-  static bool apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index);
-
-  inline SubstLookupSubTable& serialize_subtable (hb_serialize_context_t *c,
-						  unsigned int i)
-  { return get_subtables<SubstLookupSubTable> ()[i].serialize (c, this); }
-
-  inline bool serialize_single (hb_serialize_context_t *c,
-				uint32_t lookup_props,
-			        Supplier<GlyphID> &glyphs,
-			        Supplier<GlyphID> &substitutes,
-			        unsigned int num_glyphs)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Single, lookup_props, 1))) return_trace (false);
-    return_trace (serialize_subtable (c, 0).u.single.serialize (c, glyphs, substitutes, num_glyphs));
-  }
-
-  inline bool serialize_multiple (hb_serialize_context_t *c,
-				  uint32_t lookup_props,
-				  Supplier<GlyphID> &glyphs,
-				  Supplier<unsigned int> &substitute_len_list,
-				  unsigned int num_glyphs,
-				  Supplier<GlyphID> &substitute_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Multiple, lookup_props, 1))) return_trace (false);
-    return_trace (serialize_subtable (c, 0).u.multiple.serialize (c,
-								  glyphs,
-								  substitute_len_list,
-								  num_glyphs,
-								  substitute_glyphs_list));
-  }
-
-  inline bool serialize_alternate (hb_serialize_context_t *c,
-				   uint32_t lookup_props,
-				   Supplier<GlyphID> &glyphs,
-				   Supplier<unsigned int> &alternate_len_list,
-				   unsigned int num_glyphs,
-				   Supplier<GlyphID> &alternate_glyphs_list)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Alternate, lookup_props, 1))) return_trace (false);
-    return_trace (serialize_subtable (c, 0).u.alternate.serialize (c,
-								   glyphs,
-								   alternate_len_list,
-								   num_glyphs,
-								   alternate_glyphs_list));
-  }
-
-  inline bool serialize_ligature (hb_serialize_context_t *c,
-				  uint32_t lookup_props,
-				  Supplier<GlyphID> &first_glyphs,
-				  Supplier<unsigned int> &ligature_per_first_glyph_count_list,
-				  unsigned int num_first_glyphs,
-				  Supplier<GlyphID> &ligatures_list,
-				  Supplier<unsigned int> &component_count_list,
-				  Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
-  {
-    TRACE_SERIALIZE (this);
-    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Ligature, lookup_props, 1))) return_trace (false);
-    return_trace (serialize_subtable (c, 0).u.ligature.serialize (c,
-								  first_glyphs,
-								  ligature_per_first_glyph_count_list,
-								  num_first_glyphs,
-								  ligatures_list,
-								  component_count_list,
-								  component_list));
-  }
-
-  template <typename context_t>
-  static inline typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);
-
-  template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c) const
-  { return Lookup::dispatch<SubstLookupSubTable> (c); }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    if (unlikely (!Lookup::sanitize (c))) return_trace (false);
-    if (unlikely (!dispatch (c))) return_trace (false);
-
-    if (unlikely (get_type () == SubstLookupSubTable::Extension))
-    {
-      /* The spec says all subtables of an Extension lookup should
-       * have the same type, which shall not be the Extension type
-       * itself. This is specially important if one has a reverse type! */
-      unsigned int type = get_subtable (0).u.extension.get_type ();
-      if (unlikely (type == SubstLookupSubTable::Extension))
-	return_trace (false);
-      unsigned int count = get_subtable_count ();
-      for (unsigned int i = 1; i < count; i++)
-        if (get_subtable (i).u.extension.get_type () != type)
-	  return_trace (false);
-    }
-    return_trace (true);
-  }
-};
-
-typedef OffsetListOf<SubstLookup> SubstLookupList;
-
-/*
- * GSUB -- The Glyph Substitution Table
- */
-
-struct GSUB : GSUBGPOS
+#ifndef HB_NO_OT_LAYOUT
+/*static*/ inline bool ExtensionSubst::is_reverse () const
 {
-  static const hb_tag_t tableTag	= HB_OT_TAG_GSUB;
-
-  inline const SubstLookup& get_lookup (unsigned int i) const
-  { return CastR<SubstLookup> (GSUBGPOS::get_lookup (i)); }
-
-  static inline void substitute_start (hb_font_t *font, hb_buffer_t *buffer);
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    if (unlikely (!GSUBGPOS::sanitize (c))) return_trace (false);
-    const OffsetTo<SubstLookupList> &list = CastR<OffsetTo<SubstLookupList> > (lookupList);
-    return_trace (list.sanitize (c, this));
-  }
-};
-
-
-void
-GSUB::substitute_start (hb_font_t *font, hb_buffer_t *buffer)
+  return SubstLookup::lookup_type_is_reverse (get_type ());
+}
+template <typename context_t>
+/*static*/ typename context_t::return_t SubstLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
 {
-  _hb_buffer_assert_gsubgpos_vars (buffer);
-
-  const GDEF &gdef = *hb_ot_layout_from_face (font->face)->gdef;
-  unsigned int count = buffer->len;
-  for (unsigned int i = 0; i < count; i++)
-  {
-    _hb_glyph_info_set_glyph_props (&buffer->info[i], gdef.get_glyph_props (buffer->info[i].codepoint));
-    _hb_glyph_info_clear_lig_props (&buffer->info[i]);
-    buffer->info[i].syllable() = 0;
-  }
+  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (lookup_index);
+  return l.dispatch (c);
 }
 
-
-/* Out-of-class implementation for methods recursing */
-
-/*static*/ inline bool ExtensionSubst::is_reverse (void) const
+/*static*/ typename hb_closure_context_t::return_t SubstLookup::closure_glyphs_recurse_func (hb_closure_context_t *c, unsigned lookup_index, hb_set_t *covered_seq_indices, unsigned seq_index, unsigned end_index)
 {
-  unsigned int type = get_type ();
-  if (unlikely (type == SubstLookupSubTable::Extension))
-    return CastR<ExtensionSubst> (get_subtable<LookupSubTable>()).is_reverse ();
-  return SubstLookup::lookup_type_is_reverse (type);
+  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (lookup_index);
+  if (l.may_have_non_1to1 ())
+      hb_set_add_range (covered_seq_indices, seq_index, end_index);
+  return l.dispatch (c);
 }
 
-template <typename context_t>
-/*static*/ inline typename context_t::return_t SubstLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
+template <>
+inline hb_closure_lookups_context_t::return_t
+SubstLookup::dispatch_recurse_func<hb_closure_lookups_context_t> (hb_closure_lookups_context_t *c, unsigned this_index)
 {
-  const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
-  const SubstLookup &l = gsub.get_lookup (lookup_index);
-  return l.dispatch (c);
+  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (this_index);
+  return l.closure_lookups (c, this_index);
 }
 
-/*static*/ inline bool SubstLookup::apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index)
+template <>
+inline bool SubstLookup::dispatch_recurse_func<hb_ot_apply_context_t> (hb_ot_apply_context_t *c, unsigned int lookup_index)
 {
-  const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
-  const SubstLookup &l = gsub.get_lookup (lookup_index);
+  auto *gsub = c->face->table.GSUB.get_relaxed ();
+  const SubstLookup &l = gsub->table->get_lookup (lookup_index);
   unsigned int saved_lookup_props = c->lookup_props;
   unsigned int saved_lookup_index = c->lookup_index;
   c->set_lookup_index (lookup_index);
   c->set_lookup_props (l.get_props ());
-  bool ret = l.dispatch (c);
+
+  bool ret = false;
+  auto *accel = gsub->get_accel (lookup_index);
+  ret = accel && accel->apply (c, l.get_subtable_count (), false);
+
   c->set_lookup_index (saved_lookup_index);
   c->set_lookup_props (saved_lookup_props);
   return ret;
 }
+#endif
 
-
+} /* namespace GSUB_impl */
+} /* namespace Layout */
 } /* namespace OT */