HarfBuzz: Update to version 4.2.0

22 files changed, 2061 insertions, 0 deletions

diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSet.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSet.hh
new file mode 100644
index 0000000000..484f347468
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSet.hh
@@ -0,0 +1,110 @@
+#ifndef OT_LAYOUT_GSUB_ALTERNATESET_HH
+#define OT_LAYOUT_GSUB_ALTERNATESET_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct AlternateSet
+{
+  protected:
+  Array16Of<HBGlyphID16>
+                alternates;             /* Array of alternate GlyphIDs--in
+                                         * arbitrary order */
+  public:
+  DEFINE_SIZE_ARRAY (2, alternates);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (alternates.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return hb_any (alternates, glyphs); }
+
+  void closure (hb_closure_context_t *c) const
+  { c->output->add_array (alternates.arrayZ, alternates.len); }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { c->output->add_array (alternates.arrayZ, alternates.len); }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    unsigned int count = alternates.len;
+
+    if (unlikely (!count)) 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 alt_index is MAX_VALUE, randomize feature if it is the rand feature. */
+    if (alt_index == HB_OT_MAP_MAX_VALUE && c->random)
+    {
+      /* Maybe we can do better than unsafe-to-break all; but since we are
+       * changing random state, it would be hard to track that.  Good 'nough. */
+      c->buffer->unsafe_to_break (0, c->buffer->len);
+      alt_index = c->random_number () % count + 1;
+    }
+
+    if (unlikely (alt_index > count || alt_index == 0)) return_trace (false);
+
+    c->replace_glyph (alternates[alt_index - 1]);
+
+    return_trace (true);
+  }
+
+  unsigned
+  get_alternates (unsigned        start_offset,
+                  unsigned       *alternate_count  /* IN/OUT.  May be NULL. */,
+                  hb_codepoint_t *alternate_glyphs /* OUT.     May be NULL. */) const
+  {
+    if (alternates.len && alternate_count)
+    {
+      + alternates.sub_array (start_offset, alternate_count)
+      | hb_sink (hb_array (alternate_glyphs, *alternate_count))
+      ;
+    }
+    return alternates.len;
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator alts)
+  {
+    TRACE_SERIALIZE (this);
+    return_trace (alternates.serialize (c, alts));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto it =
+      + hb_iter (alternates)
+      | hb_filter (glyphset)
+      | hb_map (glyph_map)
+      ;
+
+    auto *out = c->serializer->start_embed (*this);
+    return_trace (out->serialize (c->serializer, it) &&
+                  out->alternates);
+  }
+};
+
+}
+}
+}
+
+
+#endif /* OT_LAYOUT_GSUB_ALTERNATESET_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubst.hh
new file mode 100644
index 0000000000..e5d999261f
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubst.hh
@@ -0,0 +1,51 @@
+#ifndef OT_LAYOUT_GSUB_ALTERNATESUBST_HH
+#define OT_LAYOUT_GSUB_ALTERNATESUBST_HH
+
+#include "AlternateSubstFormat1.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct AlternateSubst
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  AlternateSubstFormat1 format1;
+  } u;
+  public:
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) 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, std::forward<Ts> (ds)...));
+    default:return_trace (c->default_return_value ());
+    }
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> glyphs,
+                  hb_array_t<const unsigned int> alternate_len_list,
+                  hb_array_t<const HBGlyphID16> alternate_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (u.format))) return_trace (false);
+    unsigned int format = 1;
+    u.format = format;
+    switch (u.format) {
+    case 1: return_trace (u.format1.serialize (c, glyphs, alternate_len_list, alternate_glyphs_list));
+    default:return_trace (false);
+    }
+  }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_ALTERNATESUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubstFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubstFormat1.hh
new file mode 100644
index 0000000000..af1cd7bedb
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubstFormat1.hh
@@ -0,0 +1,128 @@
+#ifndef OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
+
+#include "AlternateSet.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct AlternateSubstFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  Array16OfOffset16To<AlternateSet>
+                alternateSet;           /* Array of AlternateSet tables
+                                         * ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_ARRAY (6, alternateSet);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  bool may_have_non_1to1 () const
+  { return false; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_zip (this+coverage, alternateSet)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const AlternateSet &_) { _.closure (c); })
+    ;
+
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    + hb_zip (this+coverage, alternateSet)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const AlternateSet &_) { _.collect_glyphs (c); })
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  unsigned
+  get_glyph_alternates (hb_codepoint_t  gid,
+                        unsigned        start_offset,
+                        unsigned       *alternate_count  /* IN/OUT.  May be NULL. */,
+                        hb_codepoint_t *alternate_glyphs /* OUT.     May be NULL. */) const
+  { return (this+alternateSet[(this+coverage).get_coverage (gid)])
+           .get_alternates (start_offset, alternate_count, alternate_glyphs); }
+
+  bool apply (hb_ot_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+alternateSet[index]).apply (c));
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> glyphs,
+                  hb_array_t<const unsigned int> alternate_len_list,
+                  hb_array_t<const HBGlyphID16> alternate_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    if (unlikely (!alternateSet.serialize (c, glyphs.length))) return_trace (false);
+    for (unsigned int i = 0; i < glyphs.length; i++)
+    {
+      unsigned int alternate_len = alternate_len_list[i];
+      if (unlikely (!alternateSet[i]
+                        .serialize_serialize (c, alternate_glyphs_list.sub_array (0, alternate_len))))
+        return_trace (false);
+      alternate_glyphs_list += alternate_len;
+    }
+    return_trace (coverage.serialize_serialize (c, glyphs));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->format = format;
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+    + hb_zip (this+coverage, alternateSet)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter (subset_offset_array (c, out->alternateSet, this), hb_second)
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+    out->coverage.serialize_serialize (c->serializer, new_coverage.iter ());
+    return_trace (bool (new_coverage));
+  }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/ChainContextSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ChainContextSubst.hh
new file mode 100644
index 0000000000..bbb88b222f
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ChainContextSubst.hh
@@ -0,0 +1,18 @@
+#ifndef OT_LAYOUT_GSUB_CHAINCONTEXTSUBST_HH
+#define OT_LAYOUT_GSUB_CHAINCONTEXTSUBST_HH
+
+// TODO(garretrieger): move to new layout.
+#include "../../../hb-ot-layout-gsubgpos.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct ChainContextSubst : ChainContext {};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_CHAINCONTEXTSUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/Common.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Common.hh
new file mode 100644
index 0000000000..f4c78a9f02
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Common.hh
@@ -0,0 +1,21 @@
+#ifndef OT_LAYOUT_GSUB_COMMON_HH
+#define OT_LAYOUT_GSUB_COMMON_HH
+
+#include "../../../hb-serialize.hh"
+#include "../../../hb-ot-layout-gsubgpos.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+typedef hb_pair_t<hb_codepoint_t, hb_codepoint_t> hb_codepoint_pair_t;
+
+template<typename Iterator>
+static void SingleSubst_serialize (hb_serialize_context_t *c,
+                                   Iterator it);
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GSUB_COMMON_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/ContextSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ContextSubst.hh
new file mode 100644
index 0000000000..2af54e8ff4
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ContextSubst.hh
@@ -0,0 +1,18 @@
+#ifndef OT_LAYOUT_GSUB_CONTEXTSUBST_HH
+#define OT_LAYOUT_GSUB_CONTEXTSUBST_HH
+
+// TODO(garretrieger): move to new layout.
+#include "../../../hb-ot-layout-gsubgpos.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct ContextSubst : Context {};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_CONTEXTSUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/ExtensionSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ExtensionSubst.hh
new file mode 100644
index 0000000000..40a3ff439f
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ExtensionSubst.hh
@@ -0,0 +1,22 @@
+#ifndef OT_LAYOUT_GSUB_EXTENSIONSUBST_HH
+#define OT_LAYOUT_GSUB_EXTENSIONSUBST_HH
+
+// TODO(garretrieger): move to new layout.
+#include "../../../hb-ot-layout-gsubgpos.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct ExtensionSubst : Extension<ExtensionSubst>
+{
+  typedef struct SubstLookupSubTable SubTable;
+  bool is_reverse () const;
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_EXTENSIONSUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/GSUB.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/GSUB.hh
new file mode 100644
index 0000000000..ad153ce8d7
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/GSUB.hh
@@ -0,0 +1,58 @@
+#ifndef OT_LAYOUT_GSUB_GSUB_HH
+#define OT_LAYOUT_GSUB_GSUB_HH
+
+// TODO(garretrieger): move to new layout.
+#include "../../../hb-ot-layout-gsubgpos.hh"
+#include "Common.hh"
+#include "SubstLookup.hh"
+
+using OT::Layout::GSUB::SubstLookup;
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+/*
+ * GSUB -- Glyph Substitution
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/gsub
+ */
+
+struct GSUB : GSUBGPOS
+{
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_GSUB;
+
+  const SubstLookup& get_lookup (unsigned int i) const
+  { return static_cast<const SubstLookup &> (GSUBGPOS::get_lookup (i)); }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    hb_subset_layout_context_t l (c, tableTag, c->plan->gsub_lookups, c->plan->gsub_langsys, c->plan->gsub_features);
+    return GSUBGPOS::subset<SubstLookup> (&l);
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  { return GSUBGPOS::sanitize<SubstLookup> (c); }
+
+  HB_INTERNAL bool is_blocklisted (hb_blob_t *blob,
+                                   hb_face_t *face) const;
+
+  void closure_lookups (hb_face_t      *face,
+                        const hb_set_t *glyphs,
+                        hb_set_t       *lookup_indexes /* IN/OUT */) const
+  { GSUBGPOS::closure_lookups<SubstLookup> (face, glyphs, lookup_indexes); }
+
+  typedef GSUBGPOS::accelerator_t<GSUB> accelerator_t;
+};
+
+
+}
+}
+
+struct GSUB_accelerator_t : Layout::GSUB::GSUB::accelerator_t {
+  GSUB_accelerator_t (hb_face_t *face) : Layout::GSUB::GSUB::accelerator_t (face) {}
+};
+
+
+}
+
+#endif  /* OT_LAYOUT_GSUB_GSUB_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/Ligature.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Ligature.hh
new file mode 100644
index 0000000000..0448d925d1
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Ligature.hh
@@ -0,0 +1,135 @@
+#ifndef OT_LAYOUT_GSUB_LIGATURE_HH
+#define OT_LAYOUT_GSUB_LIGATURE_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct Ligature
+{
+  protected:
+  HBGlyphID16   ligGlyph;               /* GlyphID of ligature to substitute */
+  HeadlessArrayOf<HBGlyphID16>
+                component;              /* Array of component GlyphIDs--start
+                                         * with the second  component--ordered
+                                         * in writing direction */
+  public:
+  DEFINE_SIZE_ARRAY (4, component);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (ligGlyph.sanitize (c) && component.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return hb_all (component, glyphs); }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    if (!intersects (c->glyphs)) return;
+    c->output->add (ligGlyph);
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    c->input->add_array (component.arrayZ, component.get_length ());
+    c->output->add (ligGlyph);
+  }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  {
+    if (c->len != component.lenP1)
+      return false;
+
+    for (unsigned int i = 1; i < c->len; i++)
+      if (likely (c->glyphs[i] != component[i]))
+        return false;
+
+    return true;
+  }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    unsigned int count = component.lenP1;
+
+    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);
+    }
+
+    unsigned int total_component_count = 0;
+
+    unsigned int match_end = 0;
+    unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
+
+    if (likely (!match_input (c, count,
+                              &component[1],
+                              match_glyph,
+                              nullptr,
+                              &match_end,
+                              match_positions,
+                              &total_component_count)))
+    {
+      c->buffer->unsafe_to_concat (c->buffer->idx, match_end);
+      return_trace (false);
+    }
+
+    ligate_input (c,
+                  count,
+                  match_positions,
+                  match_end,
+                  ligGlyph,
+                  total_component_count);
+
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  hb_codepoint_t ligature,
+                  Iterator components /* Starting from second */)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    ligGlyph = ligature;
+    if (unlikely (!component.serialize (c, components))) return_trace (false);
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c, unsigned coverage_idx) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    if (!intersects (&glyphset) || !glyphset.has (ligGlyph)) return_trace (false);
+    // Ensure Coverage table is always packed after this.
+    c->serializer->add_virtual_link (coverage_idx);
+
+    auto it =
+      + hb_iter (component)
+      | hb_map (glyph_map)
+      ;
+
+    auto *out = c->serializer->start_embed (*this);
+    return_trace (out->serialize (c->serializer,
+                                  glyph_map[ligGlyph],
+                                  it));  }
+};
+
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_LIGATURE_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSet.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSet.hh
new file mode 100644
index 0000000000..185b324b35
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSet.hh
@@ -0,0 +1,118 @@
+#ifndef OT_LAYOUT_GSUB_LIGATURESET_HH
+#define OT_LAYOUT_GSUB_LIGATURESET_HH
+
+#include "Common.hh"
+#include "Ligature.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct LigatureSet
+{
+  protected:
+  Array16OfOffset16To<Ligature>
+                ligature;               /* Array LigatureSet tables
+                                         * ordered by preference */
+  public:
+  DEFINE_SIZE_ARRAY (2, ligature);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (ligature.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return
+    + hb_iter (ligature)
+    | hb_map (hb_add (this))
+    | hb_map ([glyphs] (const Ligature &_) { return _.intersects (glyphs); })
+    | hb_any
+    ;
+  }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_iter (ligature)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const Ligature &_) { _.closure (c); })
+    ;
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    + hb_iter (ligature)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const Ligature &_) { _.collect_glyphs (c); })
+    ;
+  }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  {
+    return
+    + hb_iter (ligature)
+    | hb_map (hb_add (this))
+    | hb_map ([c] (const Ligature &_) { return _.would_apply (c); })
+    | hb_any
+    ;
+  }
+
+  bool apply (hb_ot_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);
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_array_t<const HBGlyphID16> ligatures,
+                  hb_array_t<const unsigned int> component_count_list,
+                  hb_array_t<const HBGlyphID16> &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, ligatures.length))) return_trace (false);
+    for (unsigned int i = 0; i < ligatures.length; i++)
+    {
+      unsigned int component_count = (unsigned) hb_max ((int) component_count_list[i] - 1, 0);
+      if (unlikely (!ligature[i].serialize_serialize (c,
+                                                      ligatures[i],
+                                                      component_list.sub_array (0, component_count))))
+        return_trace (false);
+      component_list += component_count;
+    }
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c, unsigned coverage_idx) const
+  {
+    TRACE_SUBSET (this);
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+
+    + hb_iter (ligature)
+    | hb_filter (subset_offset_array (c, out->ligature, this, coverage_idx))
+    | hb_drain
+    ;
+
+    if (bool (out->ligature))
+      // Ensure Coverage table is always packed after this.
+      c->serializer->add_virtual_link (coverage_idx);
+
+    return_trace (bool (out->ligature));
+  }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_LIGATURESET_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubst.hh
new file mode 100644
index 0000000000..a029bf5e9f
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubst.hh
@@ -0,0 +1,59 @@
+#ifndef OT_LAYOUT_GSUB_LIGATURESUBST_HH
+#define OT_LAYOUT_GSUB_LIGATURESUBST_HH
+
+#include "Common.hh"
+#include "LigatureSubstFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct LigatureSubst
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  LigatureSubstFormat1  format1;
+  } u;
+
+  public:
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) 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, std::forward<Ts> (ds)...));
+    default:return_trace (c->default_return_value ());
+    }
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> first_glyphs,
+                  hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
+                  hb_array_t<const HBGlyphID16> ligatures_list,
+                  hb_array_t<const unsigned int> component_count_list,
+                  hb_array_t<const HBGlyphID16> 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 = format;
+    switch (u.format) {
+    case 1: return_trace (u.format1.serialize (c,
+                                               first_glyphs,
+                                               ligature_per_first_glyph_count_list,
+                                               ligatures_list,
+                                               component_count_list,
+                                               component_list));
+    default:return_trace (false);
+    }
+  }
+};
+
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_LIGATURESUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubstFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubstFormat1.hh
new file mode 100644
index 0000000000..19dfe98469
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/LigatureSubstFormat1.hh
@@ -0,0 +1,165 @@
+#ifndef OT_LAYOUT_GSUB_LIGATURESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_LIGATURESUBSTFORMAT1_HH
+
+#include "Common.hh"
+#include "LigatureSet.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct LigatureSubstFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  Array16OfOffset16To<LigatureSet>
+                ligatureSet;            /* Array LigatureSet tables
+                                         * ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_ARRAY (6, ligatureSet);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return
+    + hb_zip (this+coverage, ligatureSet)
+    | hb_filter (*glyphs, hb_first)
+    | hb_map (hb_second)
+    | hb_map ([this, glyphs] (const Offset16To<LigatureSet> &_)
+              { return (this+_).intersects (glyphs); })
+    | hb_any
+    ;
+  }
+
+  bool may_have_non_1to1 () const
+  { return true; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_zip (this+coverage, ligatureSet)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const LigatureSet &_) { _.closure (c); })
+    ;
+
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+
+    + hb_zip (this+coverage, ligatureSet)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const LigatureSet &_) { _.collect_glyphs (c); })
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  {
+    unsigned int index = (this+coverage).get_coverage (c->glyphs[0]);
+    if (likely (index == NOT_COVERED)) return false;
+
+    const LigatureSet &lig_set = this+ligatureSet[index];
+    return lig_set.would_apply (c);
+  }
+
+  bool apply (hb_ot_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);
+
+    const LigatureSet &lig_set = this+ligatureSet[index];
+    return_trace (lig_set.apply (c));
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> first_glyphs,
+                  hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
+                  hb_array_t<const HBGlyphID16> ligatures_list,
+                  hb_array_t<const unsigned int> component_count_list,
+                  hb_array_t<const HBGlyphID16> 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, first_glyphs.length))) return_trace (false);
+    for (unsigned int i = 0; i < first_glyphs.length; i++)
+    {
+      unsigned int ligature_count = ligature_per_first_glyph_count_list[i];
+      if (unlikely (!ligatureSet[i]
+                        .serialize_serialize (c,
+                                              ligatures_list.sub_array (0, ligature_count),
+                                              component_count_list.sub_array (0, ligature_count),
+                                              component_list))) return_trace (false);
+      ligatures_list += ligature_count;
+      component_count_list += ligature_count;
+    }
+    return_trace (coverage.serialize_serialize (c, first_glyphs));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->format = format;
+
+    // Due to a bug in some older versions of windows 7 the Coverage table must be
+    // packed after the LigatureSet and Ligature tables, so serialize Coverage first
+    // which places it last in the packed order.
+    hb_set_t new_coverage;
+    + hb_zip (this+coverage, hb_iter (ligatureSet) | hb_map (hb_add (this)))
+    | hb_filter (glyphset, hb_first)
+    | hb_filter ([&] (const LigatureSet& _) {
+      return _.intersects (&glyphset);
+    }, hb_second)
+    | hb_map (hb_first)
+    | hb_sink (new_coverage);
+
+    if (!c->serializer->push<Coverage> ()
+        ->serialize (c->serializer,
+                     + new_coverage.iter () | hb_map_retains_sorting (glyph_map)))
+    {
+      c->serializer->pop_discard ();
+      return_trace (false);
+    }
+
+    unsigned coverage_idx = c->serializer->pop_pack ();
+     c->serializer->add_link (out->coverage, coverage_idx);
+
+    + hb_zip (this+coverage, ligatureSet)
+    | hb_filter (new_coverage, hb_first)
+    | hb_map (hb_second)
+    // to ensure that the repacker always orders the coverage table after the LigatureSet
+    // and LigatureSubtable's they will be linked to the Coverage table via a virtual link
+    // the coverage table object idx is passed down to facilitate this.
+    | hb_apply (subset_offset_array (c, out->ligatureSet, this, coverage_idx))
+    ;
+
+    return_trace (bool (new_coverage));
+  }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_LIGATURESUBSTFORMAT1_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubst.hh
new file mode 100644
index 0000000000..b289175504
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubst.hh
@@ -0,0 +1,53 @@
+#ifndef OT_LAYOUT_GSUB_MULTIPLESUBST_HH
+#define OT_LAYOUT_GSUB_MULTIPLESUBST_HH
+
+#include "Common.hh"
+#include "MultipleSubstFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct MultipleSubst
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  MultipleSubstFormat1  format1;
+  } u;
+
+  public:
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) 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, std::forward<Ts> (ds)...));
+    default:return_trace (c->default_return_value ());
+    }
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> glyphs,
+                  hb_array_t<const unsigned int> substitute_len_list,
+                  hb_array_t<const HBGlyphID16> substitute_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (u.format))) return_trace (false);
+    unsigned int format = 1;
+    u.format = format;
+    switch (u.format) {
+    case 1: return_trace (u.format1.serialize (c, glyphs, substitute_len_list, substitute_glyphs_list));
+    default:return_trace (false);
+    }
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GSUB_MULTIPLESUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubstFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubstFormat1.hh
new file mode 100644
index 0000000000..54c6dc8478
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/MultipleSubstFormat1.hh
@@ -0,0 +1,120 @@
+#ifndef OT_LAYOUT_GSUB_MULTIPLESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_MULTIPLESUBSTFORMAT1_HH
+
+#include "Common.hh"
+#include "Sequence.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct MultipleSubstFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  Array16OfOffset16To<Sequence>
+                sequence;               /* Array of Sequence tables
+                                         * ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_ARRAY (6, sequence);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && sequence.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  bool may_have_non_1to1 () const
+  { return true; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_zip (this+coverage, sequence)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const Sequence &_) { _.closure (c); })
+    ;
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    + hb_zip (this+coverage, sequence)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const Sequence &_) { _.collect_glyphs (c); })
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  bool apply (hb_ot_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));
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> glyphs,
+                  hb_array_t<const unsigned int> substitute_len_list,
+                  hb_array_t<const HBGlyphID16> substitute_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    if (unlikely (!sequence.serialize (c, glyphs.length))) return_trace (false);
+    for (unsigned int i = 0; i < glyphs.length; i++)
+    {
+      unsigned int substitute_len = substitute_len_list[i];
+      if (unlikely (!sequence[i]
+                        .serialize_serialize (c, substitute_glyphs_list.sub_array (0, substitute_len))))
+        return_trace (false);
+      substitute_glyphs_list += substitute_len;
+    }
+    return_trace (coverage.serialize_serialize (c, glyphs));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->format = format;
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+    + hb_zip (this+coverage, sequence)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter (subset_offset_array (c, out->sequence, this), hb_second)
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+    out->coverage.serialize_serialize (c->serializer, new_coverage.iter ());
+    return_trace (bool (new_coverage));
+  }
+};
+
+}
+}
+}
+
+
+#endif /* OT_LAYOUT_GSUB_MULTIPLESUBSTFORMAT1_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubst.hh
new file mode 100644
index 0000000000..435d80fd31
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubst.hh
@@ -0,0 +1,36 @@
+#ifndef OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBST_HH
+#define OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBST_HH
+
+#include "Common.hh"
+#include "ReverseChainSingleSubstFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct ReverseChainSingleSubst
+{
+  protected:
+  union {
+  HBUINT16                              format;         /* Format identifier */
+  ReverseChainSingleSubstFormat1        format1;
+  } u;
+
+  public:
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) 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, std::forward<Ts> (ds)...));
+    default:return_trace (c->default_return_value ());
+    }
+  }
+};
+
+}
+}
+}
+
+#endif  /* HB_OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubstFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubstFormat1.hh
new file mode 100644
index 0000000000..7a79a9df25
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/ReverseChainSingleSubstFormat1.hh
@@ -0,0 +1,228 @@
+#ifndef OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct ReverseChainSingleSubstFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of table */
+  Array16OfOffset16To<Coverage>
+                backtrack;              /* Array of coverage tables
+                                         * in backtracking sequence, in glyph
+                                         * sequence order */
+  Array16OfOffset16To<Coverage>
+                lookaheadX;             /* Array of coverage tables
+                                         * in lookahead sequence, in glyph
+                                         * sequence order */
+  Array16Of<HBGlyphID16>
+                substituteX;            /* Array of substitute
+                                         * GlyphIDs--ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_MIN (10);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
+      return_trace (false);
+    const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+    if (!lookahead.sanitize (c, this))
+      return_trace (false);
+    const Array16Of<HBGlyphID16> &substitute = StructAfter<Array16Of<HBGlyphID16>> (lookahead);
+    return_trace (substitute.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    if (!(this+coverage).intersects (glyphs))
+      return false;
+
+    const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+
+    unsigned int count;
+
+    count = backtrack.len;
+    for (unsigned int i = 0; i < count; i++)
+      if (!(this+backtrack[i]).intersects (glyphs))
+        return false;
+
+    count = lookahead.len;
+    for (unsigned int i = 0; i < count; i++)
+      if (!(this+lookahead[i]).intersects (glyphs))
+        return false;
+
+    return true;
+  }
+
+  bool may_have_non_1to1 () const
+  { return false; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    if (!intersects (c->glyphs)) return;
+
+    const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+    const Array16Of<HBGlyphID16> &substitute = StructAfter<Array16Of<HBGlyphID16>> (lookahead);
+
+    + hb_zip (this+coverage, substitute)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_sink (c->output)
+    ;
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+
+    unsigned int count;
+
+    count = backtrack.len;
+    for (unsigned int i = 0; i < count; i++)
+      if (unlikely (!(this+backtrack[i]).collect_coverage (c->before))) return;
+
+    const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+    count = lookahead.len;
+    for (unsigned int i = 0; i < count; i++)
+      if (unlikely (!(this+lookahead[i]).collect_coverage (c->after))) return;
+
+    const Array16Of<HBGlyphID16> &substitute = StructAfter<Array16Of<HBGlyphID16>> (lookahead);
+    count = substitute.len;
+    c->output->add_array (substitute.arrayZ, substitute.len);
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  bool apply (hb_ot_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 Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+    const Array16Of<HBGlyphID16> &substitute = StructAfter<Array16Of<HBGlyphID16>> (lookahead);
+
+    if (unlikely (index >= substitute.len)) return_trace (false);
+
+    unsigned int start_index = 0, end_index = 0;
+    if (match_backtrack (c,
+                         backtrack.len, (HBUINT16 *) backtrack.arrayZ,
+                         match_coverage, this,
+                         &start_index) &&
+        match_lookahead (c,
+                         lookahead.len, (HBUINT16 *) lookahead.arrayZ,
+                         match_coverage, this,
+                         c->buffer->idx + 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);
+    }
+    else
+    {
+      c->buffer->unsafe_to_concat_from_outbuffer (start_index, end_index);
+      return_trace (false);
+    }
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_iterator (Iterator))>
+  bool serialize_coverage_offset_array (hb_subset_context_t *c, Iterator it) const
+  {
+    TRACE_SERIALIZE (this);
+    auto *out = c->serializer->start_embed<Array16OfOffset16To<Coverage>> ();
+
+    if (unlikely (!c->serializer->allocate_size<HBUINT16> (HBUINT16::static_size)))
+      return_trace (false);
+
+    for (auto& offset : it) {
+      auto *o = out->serialize_append (c->serializer);
+      if (unlikely (!o) || !o->serialize_subset (c, offset, this))
+        return_trace (false);
+    }
+
+    return_trace (true);
+  }
+
+  template<typename Iterator, typename BacktrackIterator, typename LookaheadIterator,
+           hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_pair_t)),
+           hb_requires (hb_is_iterator (BacktrackIterator)),
+           hb_requires (hb_is_iterator (LookaheadIterator))>
+  bool serialize (hb_subset_context_t *c,
+                  Iterator coverage_subst_iter,
+                  BacktrackIterator backtrack_iter,
+                  LookaheadIterator lookahead_iter) const
+  {
+    TRACE_SERIALIZE (this);
+
+    auto *out = c->serializer->start_embed (this);
+    if (unlikely (!c->serializer->check_success (out))) return_trace (false);
+    if (unlikely (!c->serializer->embed (this->format))) return_trace (false);
+    if (unlikely (!c->serializer->embed (this->coverage))) return_trace (false);
+
+    if (!serialize_coverage_offset_array (c, backtrack_iter)) return_trace (false);
+    if (!serialize_coverage_offset_array (c, lookahead_iter)) return_trace (false);
+
+    auto *substitute_out = c->serializer->start_embed<Array16Of<HBGlyphID16>> ();
+    auto substitutes =
+    + coverage_subst_iter
+    | hb_map (hb_second)
+    ;
+
+    auto glyphs =
+    + coverage_subst_iter
+    | hb_map_retains_sorting (hb_first)
+    ;
+    if (unlikely (! c->serializer->check_success (substitute_out->serialize (c->serializer, substitutes))))
+        return_trace (false);
+
+    if (unlikely (!out->coverage.serialize_serialize (c->serializer, glyphs)))
+      return_trace (false);
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (backtrack);
+    const Array16Of<HBGlyphID16> &substitute = StructAfter<Array16Of<HBGlyphID16>> (lookahead);
+
+    auto it =
+    + hb_zip (this+coverage, substitute)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter (glyphset, hb_second)
+    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID16 &> p) -> hb_codepoint_pair_t
+                              { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
+    ;
+
+    return_trace (bool (it) && serialize (c, it, backtrack.iter (), lookahead.iter ()));
+  }
+};
+
+}
+}
+}
+
+#endif  /* HB_OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/Sequence.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Sequence.hh
new file mode 100644
index 0000000000..ebd451e6ba
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/Sequence.hh
@@ -0,0 +1,103 @@
+#ifndef OT_LAYOUT_GSUB_SEQUENCE_HH
+#define OT_LAYOUT_GSUB_SEQUENCE_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct Sequence
+{
+  protected:
+  Array16Of<HBGlyphID16>
+                substitute;             /* String of GlyphIDs to substitute */
+  public:
+  DEFINE_SIZE_ARRAY (2, substitute);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (substitute.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return hb_all (substitute, glyphs); }
+
+  void closure (hb_closure_context_t *c) const
+  { c->output->add_array (substitute.arrayZ, substitute.len); }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { c->output->add_array (substitute.arrayZ, substitute.len); }
+
+  bool apply (hb_ot_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.arrayZ[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;
+    unsigned lig_id = _hb_glyph_info_get_lig_id (&c->buffer->cur());
+
+    for (unsigned int i = 0; i < count; i++)
+    {
+      /* If is attached to a ligature, don't disturb that.
+       * https://github.com/harfbuzz/harfbuzz/issues/3069 */
+      if (!lig_id)
+        _hb_glyph_info_set_lig_props_for_component (&c->buffer->cur(), i);
+      c->output_glyph_for_component (substitute.arrayZ[i], klass);
+    }
+    c->buffer->skip_glyph ();
+
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator subst)
+  {
+    TRACE_SERIALIZE (this);
+    return_trace (substitute.serialize (c, subst));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    if (!intersects (&glyphset)) return_trace (false);
+
+    auto it =
+    + hb_iter (substitute)
+    | hb_map (glyph_map)
+    ;
+
+    auto *out = c->serializer->start_embed (*this);
+    return_trace (out->serialize (c->serializer, it));
+  }
+};
+
+
+}
+}
+}
+
+
+#endif /* OT_LAYOUT_GSUB_SEQUENCE_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubst.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubst.hh
new file mode 100644
index 0000000000..786428fe45
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubst.hh
@@ -0,0 +1,75 @@
+#ifndef OT_LAYOUT_GSUB_SINGLESUBST_HH
+#define OT_LAYOUT_GSUB_SINGLESUBST_HH
+
+#include "Common.hh"
+#include "SingleSubstFormat1.hh"
+#include "SingleSubstFormat2.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct SingleSubst
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  SingleSubstFormat1    format1;
+  SingleSubstFormat2    format2;
+  } u;
+
+  public:
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) 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, std::forward<Ts> (ds)...));
+    case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+    default:return_trace (c->default_return_value ());
+    }
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_sorted_source_of (Iterator,
+                                                const hb_codepoint_pair_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator glyphs)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (u.format))) return_trace (false);
+    unsigned format = 2;
+    unsigned delta = 0;
+    if (glyphs)
+    {
+      format = 1;
+      auto get_delta = [=] (hb_codepoint_pair_t _)
+                       { return (unsigned) (_.second - _.first) & 0xFFFF; };
+      delta = get_delta (*glyphs);
+      if (!hb_all (++(+glyphs), delta, get_delta)) format = 2;
+    }
+    u.format = format;
+    switch (u.format) {
+    case 1: return_trace (u.format1.serialize (c,
+                                               + glyphs
+                                               | hb_map_retains_sorting (hb_first),
+                                               delta));
+    case 2: return_trace (u.format2.serialize (c, glyphs));
+    default:return_trace (false);
+    }
+  }
+};
+
+template<typename Iterator>
+static void
+SingleSubst_serialize (hb_serialize_context_t *c,
+                       Iterator it)
+{ c->start_embed<SingleSubst> ()->serialize (c, it); }
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GSUB_SINGLESUBST_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat1.hh
new file mode 100644
index 0000000000..3c6b2954ce
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat1.hh
@@ -0,0 +1,122 @@
+#ifndef OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct SingleSubstFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  HBUINT16      deltaGlyphID;           /* Add to original GlyphID to get
+                                         * substitute GlyphID, modulo 0x10000 */
+
+  public:
+  DEFINE_SIZE_STATIC (6);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  bool may_have_non_1to1 () const
+  { return false; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    unsigned d = deltaGlyphID;
+
+    + hb_iter (this+coverage)
+    | hb_filter (c->parent_active_glyphs ())
+    | hb_map ([d] (hb_codepoint_t g) { return (g + d) & 0xFFFFu; })
+    | hb_sink (c->output)
+    ;
+
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    unsigned d = deltaGlyphID;
+    + hb_iter (this+coverage)
+    | hb_map ([d] (hb_codepoint_t g) { return (g + d) & 0xFFFFu; })
+    | hb_sink (c->output)
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  bool apply (hb_ot_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);
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator glyphs,
+                  unsigned delta)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    if (unlikely (!coverage.serialize_serialize (c, glyphs))) return_trace (false);
+    c->check_assign (deltaGlyphID, delta, HB_SERIALIZE_ERROR_INT_OVERFLOW);
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    hb_codepoint_t delta = deltaGlyphID;
+
+    auto it =
+    + hb_iter (this+coverage)
+    | hb_filter (glyphset)
+    | hb_map_retains_sorting ([&] (hb_codepoint_t g) {
+                                return hb_codepoint_pair_t (g,
+                                                            (g + delta) & 0xFFFF); })
+    | hb_filter (glyphset, hb_second)
+    | hb_map_retains_sorting ([&] (hb_codepoint_pair_t p) -> hb_codepoint_pair_t
+                              { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
+    ;
+
+    bool ret = bool (it);
+    SingleSubst_serialize (c->serializer, it);
+    return_trace (ret);
+  }
+};
+
+}
+}
+}
+
+
+#endif /* OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat2.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat2.hh
new file mode 100644
index 0000000000..df75bb52bb
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat2.hh
@@ -0,0 +1,120 @@
+#ifndef OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH
+#define OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct SingleSubstFormat2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 2 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  Array16Of<HBGlyphID16>
+                substitute;             /* Array of substitute
+                                         * GlyphIDs--ordered by Coverage Index */
+
+  public:
+  DEFINE_SIZE_ARRAY (6, substitute);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && substitute.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  bool may_have_non_1to1 () const
+  { return false; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_zip (this+coverage, substitute)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_sink (c->output)
+    ;
+
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    + hb_zip (this+coverage, substitute)
+    | hb_map (hb_second)
+    | hb_sink (c->output)
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  bool apply (hb_ot_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);
+
+    if (unlikely (index >= substitute.len)) return_trace (false);
+
+    c->replace_glyph (substitute[index]);
+
+    return_trace (true);
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_sorted_source_of (Iterator,
+                                                hb_codepoint_pair_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator it)
+  {
+    TRACE_SERIALIZE (this);
+    auto substitutes =
+      + it
+      | hb_map (hb_second)
+      ;
+    auto glyphs =
+      + it
+      | hb_map_retains_sorting (hb_first)
+      ;
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    if (unlikely (!substitute.serialize (c, substitutes))) return_trace (false);
+    if (unlikely (!coverage.serialize_serialize (c, glyphs))) return_trace (false);
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto it =
+    + hb_zip (this+coverage, substitute)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter (glyphset, hb_second)
+    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID16 &> p) -> hb_codepoint_pair_t
+                              { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
+    ;
+
+    bool ret = bool (it);
+    SingleSubst_serialize (c->serializer, it);
+    return_trace (ret);
+  }
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookup.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookup.hh
new file mode 100644
index 0000000000..3419b5a734
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookup.hh
@@ -0,0 +1,224 @@
+#ifndef OT_LAYOUT_GSUB_SUBSTLOOKUP_HH
+#define OT_LAYOUT_GSUB_SUBSTLOOKUP_HH
+
+#include "Common.hh"
+#include "SubstLookupSubTable.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct SubstLookup : Lookup
+{
+  typedef SubstLookupSubTable SubTable;
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  { return Lookup::sanitize<SubTable> (c); }
+
+  const SubTable& get_subtable (unsigned int i) const
+  { return Lookup::get_subtable<SubTable> (i); }
+
+  static inline bool lookup_type_is_reverse (unsigned int lookup_type)
+  { return lookup_type == SubTable::ReverseChainSingle; }
+
+  bool is_reverse () const
+  {
+    unsigned int type = get_type ();
+    if (unlikely (type == SubTable::Extension))
+      return reinterpret_cast<const ExtensionSubst &> (get_subtable (0)).is_reverse ();
+    return lookup_type_is_reverse (type);
+  }
+
+  bool may_have_non_1to1 () const
+  {
+    hb_have_non_1to1_context_t c;
+    return dispatch (&c);
+  }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    return_trace (dispatch (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    hb_intersects_context_t c (glyphs);
+    return dispatch (&c);
+  }
+
+  hb_closure_context_t::return_t closure (hb_closure_context_t *c, unsigned int this_index) const
+  {
+    if (!c->should_visit_lookup (this_index))
+      return hb_closure_context_t::default_return_value ();
+
+    c->set_recurse_func (dispatch_closure_recurse_func);
+
+    hb_closure_context_t::return_t ret = dispatch (c);
+
+    c->flush ();
+
+    return ret;
+  }
+
+  hb_closure_lookups_context_t::return_t closure_lookups (hb_closure_lookups_context_t *c, unsigned this_index) const
+  {
+    if (c->is_lookup_visited (this_index))
+      return hb_closure_lookups_context_t::default_return_value ();
+
+    c->set_lookup_visited (this_index);
+    if (!intersects (c->glyphs))
+    {
+      c->set_lookup_inactive (this_index);
+      return hb_closure_lookups_context_t::default_return_value ();
+    }
+
+    c->set_recurse_func (dispatch_closure_lookups_recurse_func);
+
+    hb_closure_lookups_context_t::return_t ret = dispatch (c);
+    return ret;
+  }
+
+  hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    c->set_recurse_func (dispatch_recurse_func<hb_collect_glyphs_context_t>);
+    return dispatch (c);
+  }
+
+  template <typename set_t>
+  void collect_coverage (set_t *glyphs) const
+  {
+    hb_collect_coverage_context_t<set_t> c (glyphs);
+    dispatch (&c);
+  }
+
+  bool would_apply (hb_would_apply_context_t *c,
+                    const hb_ot_layout_lookup_accelerator_t *accel) const
+  {
+    if (unlikely (!c->len)) return false;
+    if (!accel->may_have (c->glyphs[0])) return false;
+      return dispatch (c);
+  }
+
+  static inline bool apply_recurse_func (hb_ot_apply_context_t *c, unsigned int lookup_index);
+
+  bool serialize_single (hb_serialize_context_t *c,
+                         uint32_t lookup_props,
+                         hb_sorted_array_t<const HBGlyphID16> glyphs,
+                         hb_array_t<const HBGlyphID16> substitutes)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!Lookup::serialize (c, SubTable::Single, lookup_props, 1))) return_trace (false);
+    if (c->push<SubTable> ()->u.single.serialize (c, hb_zip (glyphs, substitutes)))
+    {
+      c->add_link (get_subtables<SubTable> ()[0], c->pop_pack ());
+      return_trace (true);
+    }
+    c->pop_discard ();
+    return_trace (false);
+  }
+
+  bool serialize_multiple (hb_serialize_context_t *c,
+                           uint32_t lookup_props,
+                           hb_sorted_array_t<const HBGlyphID16> glyphs,
+                           hb_array_t<const unsigned int> substitute_len_list,
+                           hb_array_t<const HBGlyphID16> substitute_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!Lookup::serialize (c, SubTable::Multiple, lookup_props, 1))) return_trace (false);
+    if (c->push<SubTable> ()->u.multiple.
+        serialize (c,
+                   glyphs,
+                   substitute_len_list,
+                   substitute_glyphs_list))
+    {
+      c->add_link (get_subtables<SubTable> ()[0], c->pop_pack ());
+      return_trace (true);
+    }
+    c->pop_discard ();
+    return_trace (false);
+  }
+
+  bool serialize_alternate (hb_serialize_context_t *c,
+                            uint32_t lookup_props,
+                            hb_sorted_array_t<const HBGlyphID16> glyphs,
+                            hb_array_t<const unsigned int> alternate_len_list,
+                            hb_array_t<const HBGlyphID16> alternate_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!Lookup::serialize (c, SubTable::Alternate, lookup_props, 1))) return_trace (false);
+
+    if (c->push<SubTable> ()->u.alternate.
+        serialize (c,
+                   glyphs,
+                   alternate_len_list,
+                   alternate_glyphs_list))
+    {
+      c->add_link (get_subtables<SubTable> ()[0], c->pop_pack ());
+      return_trace (true);
+    }
+    c->pop_discard ();
+    return_trace (false);
+  }
+
+  bool serialize_ligature (hb_serialize_context_t *c,
+                           uint32_t lookup_props,
+                           hb_sorted_array_t<const HBGlyphID16> first_glyphs,
+                           hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
+                           hb_array_t<const HBGlyphID16> ligatures_list,
+                           hb_array_t<const unsigned int> component_count_list,
+                           hb_array_t<const HBGlyphID16> component_list /* Starting from second for each ligature */)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!Lookup::serialize (c, SubTable::Ligature, lookup_props, 1))) return_trace (false);
+    if (c->push<SubTable> ()->u.ligature.
+        serialize (c,
+                   first_glyphs,
+                   ligature_per_first_glyph_count_list,
+                   ligatures_list,
+                   component_count_list,
+                   component_list))
+    {
+      c->add_link (get_subtables<SubTable> ()[0], c->pop_pack ());
+      return_trace (true);
+    }
+    c->pop_discard ();
+    return_trace (false);
+  }
+
+  template <typename context_t>
+  static inline typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);
+
+  static inline typename hb_closure_context_t::return_t closure_glyphs_recurse_func (hb_closure_context_t *c, unsigned lookup_index, hb_set_t *covered_seq_indices, unsigned seq_index, unsigned end_index);
+
+  static inline hb_closure_context_t::return_t dispatch_closure_recurse_func (hb_closure_context_t *c, unsigned lookup_index, hb_set_t *covered_seq_indices, unsigned seq_index, unsigned end_index)
+  {
+    if (!c->should_visit_lookup (lookup_index))
+      return hb_empty_t ();
+
+    hb_closure_context_t::return_t ret = closure_glyphs_recurse_func (c, lookup_index, covered_seq_indices, seq_index, end_index);
+
+    /* While in theory we should flush here, it will cause timeouts because a recursive
+     * lookup can keep growing the glyph set.  Skip, and outer loop will retry up to
+     * HB_CLOSURE_MAX_STAGES time, which should be enough for every realistic font. */
+    //c->flush ();
+
+    return ret;
+  }
+
+  HB_INTERNAL static hb_closure_lookups_context_t::return_t dispatch_closure_lookups_recurse_func (hb_closure_lookups_context_t *c, unsigned lookup_index);
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
+  { return Lookup::dispatch<SubTable> (c, std::forward<Ts> (ds)...); }
+
+  bool subset (hb_subset_context_t *c) const
+  { return Lookup::subset<SubTable> (c); }
+};
+
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_SUBSTLOOKUP_HH */
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookupSubTable.hh b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookupSubTable.hh
new file mode 100644
index 0000000000..53e963e2a2
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GSUB/SubstLookupSubTable.hh
@@ -0,0 +1,77 @@
+#ifndef OT_LAYOUT_GSUB_SUBSTLOOKUPSUBTABLE_HH
+#define OT_LAYOUT_GSUB_SUBSTLOOKUPSUBTABLE_HH
+
+#include "Common.hh"
+#include "SingleSubst.hh"
+#include "MultipleSubst.hh"
+#include "AlternateSubst.hh"
+#include "LigatureSubst.hh"
+#include "ContextSubst.hh"
+#include "ChainContextSubst.hh"
+#include "ExtensionSubst.hh"
+#include "ReverseChainSingleSubst.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB {
+
+struct SubstLookupSubTable
+{
+  friend struct ::OT::Lookup;
+  friend struct SubstLookup;
+
+  protected:
+  union {
+  SingleSubst                   single;
+  MultipleSubst                 multiple;
+  AlternateSubst                alternate;
+  LigatureSubst                 ligature;
+  ContextSubst                  context;
+  ChainContextSubst             chainContext;
+  ExtensionSubst                extension;
+  ReverseChainSingleSubst       reverseChainContextSingle;
+  } u;
+  public:
+  DEFINE_SIZE_MIN (0);
+
+  enum Type {
+    Single              = 1,
+    Multiple            = 2,
+    Alternate           = 3,
+    Ligature            = 4,
+    Context             = 5,
+    ChainContext        = 6,
+    Extension           = 7,
+    ReverseChainSingle  = 8
+  };
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type, Ts&&... ds) const
+  {
+    TRACE_DISPATCH (this, lookup_type);
+    switch (lookup_type) {
+    case Single:                return_trace (u.single.dispatch (c, std::forward<Ts> (ds)...));
+    case Multiple:              return_trace (u.multiple.dispatch (c, std::forward<Ts> (ds)...));
+    case Alternate:             return_trace (u.alternate.dispatch (c, std::forward<Ts> (ds)...));
+    case Ligature:              return_trace (u.ligature.dispatch (c, std::forward<Ts> (ds)...));
+    case Context:               return_trace (u.context.dispatch (c, std::forward<Ts> (ds)...));
+    case ChainContext:          return_trace (u.chainContext.dispatch (c, std::forward<Ts> (ds)...));
+    case Extension:             return_trace (u.extension.dispatch (c, std::forward<Ts> (ds)...));
+    case ReverseChainSingle:    return_trace (u.reverseChainContextSingle.dispatch (c, std::forward<Ts> (ds)...));
+    default:                    return_trace (c->default_return_value ());
+    }
+  }
+
+  bool intersects (const hb_set_t *glyphs, unsigned int lookup_type) const
+  {
+    hb_intersects_context_t c (glyphs);
+    return dispatch (&c, lookup_type);
+  }
+};
+
+
+}
+}
+}
+
+#endif  /* HB_OT_LAYOUT_GSUB_SUBSTLOOKUPSUBTABLE_HH */