Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

32 files changed, 3864 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/Anchor.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/Anchor.hh
new file mode 100644
index 0000000000..49e76e7750
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/Anchor.hh
@@ -0,0 +1,83 @@
+#ifndef OT_LAYOUT_GPOS_ANCHOR_HH
+#define OT_LAYOUT_GPOS_ANCHOR_HH
+
+#include "AnchorFormat1.hh"
+#include "AnchorFormat2.hh"
+#include "AnchorFormat3.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct Anchor
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  AnchorFormat1         format1;
+  AnchorFormat2         format2;
+  AnchorFormat3         format3;
+  } u;
+  public:
+  DEFINE_SIZE_UNION (2, format);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    if (!u.format.sanitize (c)) return_trace (false);
+    switch (u.format) {
+    case 1: return_trace (u.format1.sanitize (c));
+    case 2: return_trace (u.format2.sanitize (c));
+    case 3: return_trace (u.format3.sanitize (c));
+    default:return_trace (true);
+    }
+  }
+
+  void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id,
+                   float *x, float *y) const
+  {
+    *x = *y = 0;
+    switch (u.format) {
+    case 1: u.format1.get_anchor (c, glyph_id, x, y); return;
+    case 2: u.format2.get_anchor (c, glyph_id, x, y); return;
+    case 3: u.format3.get_anchor (c, glyph_id, x, y); return;
+    default:                                          return;
+    }
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    switch (u.format) {
+    case 1: return_trace (bool (reinterpret_cast<Anchor *> (u.format1.copy (c->serializer))));
+    case 2:
+      if (c->plan->flags & HB_SUBSET_FLAGS_NO_HINTING)
+      {
+        // AnchorFormat 2 just containins extra hinting information, so
+        // if hints are being dropped convert to format 1.
+        return_trace (bool (reinterpret_cast<Anchor *> (u.format1.copy (c->serializer))));
+      }
+      return_trace (bool (reinterpret_cast<Anchor *> (u.format2.copy (c->serializer))));
+    case 3: return_trace (u.format3.subset (c));
+    default:return_trace (false);
+    }
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    switch (u.format) {
+    case 1: case 2:
+      return;
+    case 3:
+      u.format3.collect_variation_indices (c);
+      return;
+    default: return;
+    }
+  }
+};
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_ANCHOR_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat1.hh
new file mode 100644
index 0000000000..738cc31bbf
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat1.hh
@@ -0,0 +1,46 @@
+#ifndef OT_LAYOUT_GPOS_ANCHORFORMAT1_HH
+#define OT_LAYOUT_GPOS_ANCHORFORMAT1_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct AnchorFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  FWORD         xCoordinate;            /* Horizontal value--in design units */
+  FWORD         yCoordinate;            /* Vertical value--in design units */
+  public:
+  DEFINE_SIZE_STATIC (6);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id HB_UNUSED,
+                   float *x, float *y) const
+  {
+    hb_font_t *font = c->font;
+    *x = font->em_fscale_x (xCoordinate);
+    *y = font->em_fscale_y (yCoordinate);
+  }
+
+  AnchorFormat1* copy (hb_serialize_context_t *c) const
+  {
+    TRACE_SERIALIZE (this);
+    AnchorFormat1* out = c->embed<AnchorFormat1> (this);
+    if (!out) return_trace (out);
+    out->format = 1;
+    return_trace (out);
+  }
+};
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_ANCHORFORMAT1_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat2.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat2.hh
new file mode 100644
index 0000000000..70b4d19f53
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat2.hh
@@ -0,0 +1,58 @@
+#ifndef OT_LAYOUT_GPOS_ANCHORFORMAT2_HH
+#define OT_LAYOUT_GPOS_ANCHORFORMAT2_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct AnchorFormat2
+{
+
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 2 */
+  FWORD         xCoordinate;            /* Horizontal value--in design units */
+  FWORD         yCoordinate;            /* Vertical value--in design units */
+  HBUINT16      anchorPoint;            /* Index to glyph contour point */
+  public:
+  DEFINE_SIZE_STATIC (8);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id,
+                   float *x, float *y) const
+  {
+    hb_font_t *font = c->font;
+
+#ifdef HB_NO_HINTING
+    *x = font->em_fscale_x (xCoordinate);
+    *y = font->em_fscale_y (yCoordinate);
+    return;
+#endif
+
+    unsigned int x_ppem = font->x_ppem;
+    unsigned int y_ppem = font->y_ppem;
+    hb_position_t cx = 0, cy = 0;
+    bool ret;
+
+    ret = (x_ppem || y_ppem) &&
+          font->get_glyph_contour_point_for_origin (glyph_id, anchorPoint, HB_DIRECTION_LTR, &cx, &cy);
+    *x = ret && x_ppem ? cx : font->em_fscale_x (xCoordinate);
+    *y = ret && y_ppem ? cy : font->em_fscale_y (yCoordinate);
+  }
+
+  AnchorFormat2* copy (hb_serialize_context_t *c) const
+  {
+    TRACE_SERIALIZE (this);
+    return_trace (c->embed<AnchorFormat2> (this));
+  }
+};
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_ANCHORFORMAT2_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat3.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat3.hh
new file mode 100644
index 0000000000..2e30ab33c3
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorFormat3.hh
@@ -0,0 +1,100 @@
+#ifndef OT_LAYOUT_GPOS_ANCHORFORMAT3_HH
+#define OT_LAYOUT_GPOS_ANCHORFORMAT3_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct AnchorFormat3
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 3 */
+  FWORD         xCoordinate;            /* Horizontal value--in design units */
+  FWORD         yCoordinate;            /* Vertical value--in design units */
+  Offset16To<Device>
+                xDeviceTable;           /* Offset to Device table for X
+                                         * coordinate-- from beginning of
+                                         * Anchor table (may be NULL) */
+  Offset16To<Device>
+                yDeviceTable;           /* Offset to Device table for Y
+                                         * coordinate-- from beginning of
+                                         * Anchor table (may be NULL) */
+  public:
+  DEFINE_SIZE_STATIC (10);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && xDeviceTable.sanitize (c, this) && yDeviceTable.sanitize (c, this));
+  }
+
+  void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id HB_UNUSED,
+                   float *x, float *y) const
+  {
+    hb_font_t *font = c->font;
+    *x = font->em_fscale_x (xCoordinate);
+    *y = font->em_fscale_y (yCoordinate);
+
+    if (font->x_ppem || font->num_coords)
+      *x += (this+xDeviceTable).get_x_delta (font, c->var_store, c->var_store_cache);
+    if (font->y_ppem || font->num_coords)
+      *y += (this+yDeviceTable).get_y_delta (font, c->var_store, c->var_store_cache);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!out)) return_trace (false);
+    if (unlikely (!c->serializer->embed (format))) return_trace (false);
+    if (unlikely (!c->serializer->embed (xCoordinate))) return_trace (false);
+    if (unlikely (!c->serializer->embed (yCoordinate))) return_trace (false);
+
+    unsigned x_varidx = xDeviceTable ? (this+xDeviceTable).get_variation_index () : HB_OT_LAYOUT_NO_VARIATIONS_INDEX;
+    if (c->plan->layout_variation_idx_delta_map->has (x_varidx))
+    {
+      int delta = hb_second (c->plan->layout_variation_idx_delta_map->get (x_varidx));
+      if (delta != 0)
+      {
+        if (!c->serializer->check_assign (out->xCoordinate, xCoordinate + delta,
+                                          HB_SERIALIZE_ERROR_INT_OVERFLOW))
+          return_trace (false);
+      }
+    }
+
+    unsigned y_varidx = yDeviceTable ? (this+yDeviceTable).get_variation_index () : HB_OT_LAYOUT_NO_VARIATIONS_INDEX;
+    if (c->plan->layout_variation_idx_delta_map->has (y_varidx))
+    {
+      int delta = hb_second (c->plan->layout_variation_idx_delta_map->get (y_varidx));
+      if (delta != 0)
+      {
+        if (!c->serializer->check_assign (out->yCoordinate, yCoordinate + delta,
+                                          HB_SERIALIZE_ERROR_INT_OVERFLOW))
+          return_trace (false);
+      }
+    }
+
+    if (c->plan->all_axes_pinned)
+      return_trace (c->serializer->check_assign (out->format, 1, HB_SERIALIZE_ERROR_INT_OVERFLOW));
+
+    if (!c->serializer->embed (xDeviceTable)) return_trace (false);
+    if (!c->serializer->embed (yDeviceTable)) return_trace (false);
+
+    out->xDeviceTable.serialize_copy (c->serializer, xDeviceTable, this, 0, hb_serialize_context_t::Head, c->plan->layout_variation_idx_delta_map);
+    out->yDeviceTable.serialize_copy (c->serializer, yDeviceTable, this, 0, hb_serialize_context_t::Head, c->plan->layout_variation_idx_delta_map);
+    return_trace (out);
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    (this+xDeviceTable).collect_variation_indices (c);
+    (this+yDeviceTable).collect_variation_indices (c);
+  }
+};
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_ANCHORFORMAT3_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorMatrix.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorMatrix.hh
new file mode 100644
index 0000000000..c442efa1ea
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/AnchorMatrix.hh
@@ -0,0 +1,77 @@
+#ifndef OT_LAYOUT_GPOS_ANCHORMATRIX_HH
+#define OT_LAYOUT_GPOS_ANCHORMATRIX_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct AnchorMatrix
+{
+  HBUINT16      rows;                   /* Number of rows */
+  UnsizedArrayOf<Offset16To<Anchor>>
+                matrixZ;                /* Matrix of offsets to Anchor tables--
+                                         * from beginning of AnchorMatrix table */
+  public:
+  DEFINE_SIZE_ARRAY (2, matrixZ);
+
+  bool sanitize (hb_sanitize_context_t *c, unsigned int cols) const
+  {
+    TRACE_SANITIZE (this);
+    if (!c->check_struct (this)) return_trace (false);
+    if (unlikely (hb_unsigned_mul_overflows (rows, cols))) return_trace (false);
+    unsigned int count = rows * cols;
+    if (!c->check_array (matrixZ.arrayZ, count)) return_trace (false);
+    for (unsigned int i = 0; i < count; i++)
+      if (!matrixZ[i].sanitize (c, this)) return_trace (false);
+    return_trace (true);
+  }
+
+  const Anchor& get_anchor (unsigned int row, unsigned int col,
+                            unsigned int cols, bool *found) const
+  {
+    *found = false;
+    if (unlikely (row >= rows || col >= cols)) return Null (Anchor);
+    *found = !matrixZ[row * cols + col].is_null ();
+    return this+matrixZ[row * cols + col];
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_iterator (Iterator))>
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  Iterator index_iter) const
+  {
+    for (unsigned i : index_iter)
+      (this+matrixZ[i]).collect_variation_indices (c);
+  }
+
+  template <typename Iterator,
+      hb_requires (hb_is_iterator (Iterator))>
+  bool subset (hb_subset_context_t *c,
+               unsigned             num_rows,
+               Iterator             index_iter) const
+  {
+    TRACE_SUBSET (this);
+
+    auto *out = c->serializer->start_embed (this);
+
+    if (!index_iter) return_trace (false);
+    if (unlikely (!c->serializer->extend_min (out)))  return_trace (false);
+
+    out->rows = num_rows;
+    for (const unsigned i : index_iter)
+    {
+      auto *offset = c->serializer->embed (matrixZ[i]);
+      if (!offset) return_trace (false);
+      offset->serialize_subset (c, matrixZ[i], this);
+    }
+
+    return_trace (true);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_ANCHORMATRIX_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/ChainContextPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/ChainContextPos.hh
new file mode 100644
index 0000000000..d551ac2a2b
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/ChainContextPos.hh
@@ -0,0 +1,14 @@
+#ifndef OT_LAYOUT_GPOS_CHAINCONTEXTPOS_HH
+#define OT_LAYOUT_GPOS_CHAINCONTEXTPOS_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct ChainContextPos : ChainContext {};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_CHAINCONTEXTPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/Common.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/Common.hh
new file mode 100644
index 0000000000..408197454f
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/Common.hh
@@ -0,0 +1,33 @@
+#ifndef OT_LAYOUT_GPOS_COMMON_HH
+#define OT_LAYOUT_GPOS_COMMON_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+enum attach_type_t {
+  ATTACH_TYPE_NONE      = 0X00,
+
+  /* Each attachment should be either a mark or a cursive; can't be both. */
+  ATTACH_TYPE_MARK      = 0X01,
+  ATTACH_TYPE_CURSIVE   = 0X02,
+};
+
+/* buffer **position** var allocations */
+#define attach_chain() var.i16[0] /* glyph to which this attaches to, relative to current glyphs; negative for going back, positive for forward. */
+#define attach_type() var.u8[2] /* attachment type */
+/* Note! if attach_chain() is zero, the value of attach_type() is irrelevant. */
+
+template<typename Iterator, typename SrcLookup>
+static void SinglePos_serialize (hb_serialize_context_t *c,
+                                 const SrcLookup *src,
+                                 Iterator it,
+                                 const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map,
+                                 bool all_axes_pinned);
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_COMMON_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/ContextPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/ContextPos.hh
new file mode 100644
index 0000000000..2a01eaa3a6
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/ContextPos.hh
@@ -0,0 +1,14 @@
+#ifndef OT_LAYOUT_GPOS_CONTEXTPOS_HH
+#define OT_LAYOUT_GPOS_CONTEXTPOS_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct ContextPos : Context {};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_CONTEXTPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePos.hh
new file mode 100644
index 0000000000..c105cfb091
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePos.hh
@@ -0,0 +1,35 @@
+#ifndef OT_LAYOUT_GPOS_CURSIVEPOS_HH
+#define OT_LAYOUT_GPOS_CURSIVEPOS_HH
+
+#include "CursivePosFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct CursivePos
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  CursivePosFormat1     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 /* OT_LAYOUT_GPOS_CURSIVEPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh
new file mode 100644
index 0000000000..7f58fac8b8
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh
@@ -0,0 +1,301 @@
+#ifndef OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH
+
+#include "Anchor.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct EntryExitRecord
+{
+  friend struct CursivePosFormat1;
+
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (entryAnchor.sanitize (c, base) && exitAnchor.sanitize (c, base));
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const void *src_base) const
+  {
+    (src_base+entryAnchor).collect_variation_indices (c);
+    (src_base+exitAnchor).collect_variation_indices (c);
+  }
+
+  EntryExitRecord* subset (hb_subset_context_t *c,
+                           const void *src_base) const
+  {
+    TRACE_SERIALIZE (this);
+    auto *out = c->serializer->embed (this);
+    if (unlikely (!out)) return_trace (nullptr);
+
+    out->entryAnchor.serialize_subset (c, entryAnchor, src_base);
+    out->exitAnchor.serialize_subset (c, exitAnchor, src_base);
+    return_trace (out);
+  }
+
+  protected:
+  Offset16To<Anchor>
+                entryAnchor;            /* Offset to EntryAnchor table--from
+                                         * beginning of CursivePos
+                                         * subtable--may be NULL */
+  Offset16To<Anchor>
+                exitAnchor;             /* Offset to ExitAnchor table--from
+                                         * beginning of CursivePos
+                                         * subtable--may be NULL */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
+static void
+reverse_cursive_minor_offset (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction, unsigned int new_parent) {
+  int chain = pos[i].attach_chain(), type = pos[i].attach_type();
+  if (likely (!chain || 0 == (type & ATTACH_TYPE_CURSIVE)))
+    return;
+
+  pos[i].attach_chain() = 0;
+
+  unsigned int j = (int) i + chain;
+
+  /* Stop if we see new parent in the chain. */
+  if (j == new_parent)
+    return;
+
+  reverse_cursive_minor_offset (pos, j, direction, new_parent);
+
+  if (HB_DIRECTION_IS_HORIZONTAL (direction))
+    pos[j].y_offset = -pos[i].y_offset;
+  else
+    pos[j].x_offset = -pos[i].x_offset;
+
+  pos[j].attach_chain() = -chain;
+  pos[j].attach_type() = type;
+}
+
+
+struct CursivePosFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  Array16Of<EntryExitRecord>
+                entryExitRecord;        /* Array of EntryExit records--in
+                                         * Coverage Index order */
+  public:
+  DEFINE_SIZE_ARRAY (6, entryExitRecord);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && entryExitRecord.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    + hb_zip (this+coverage, entryExitRecord)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    | hb_apply ([&] (const EntryExitRecord& record) { record.collect_variation_indices (c, this); })
+    ;
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { if (unlikely (!(this+coverage).collect_coverage (c->input))) return; }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+
+    const EntryExitRecord &this_record = entryExitRecord[(this+coverage).get_coverage  (buffer->cur().codepoint)];
+    if (!this_record.entryAnchor) return_trace (false);
+
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    unsigned unsafe_from;
+    if (!skippy_iter.prev (&unsafe_from))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    const EntryExitRecord &prev_record = entryExitRecord[(this+coverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint)];
+    if (!prev_record.exitAnchor)
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    unsigned int i = skippy_iter.idx;
+    unsigned int j = buffer->idx;
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "cursive attaching glyph at %d to glyph at %d",
+			  i, j);
+    }
+
+    buffer->unsafe_to_break (i, j + 1);
+    float entry_x, entry_y, exit_x, exit_y;
+    (this+prev_record.exitAnchor).get_anchor (c, buffer->info[i].codepoint, &exit_x, &exit_y);
+    (this+this_record.entryAnchor).get_anchor (c, buffer->info[j].codepoint, &entry_x, &entry_y);
+
+    hb_glyph_position_t *pos = buffer->pos;
+
+    hb_position_t d;
+    /* Main-direction adjustment */
+    switch (c->direction) {
+      case HB_DIRECTION_LTR:
+        pos[i].x_advance  = roundf (exit_x) + pos[i].x_offset;
+
+        d = roundf (entry_x) + pos[j].x_offset;
+        pos[j].x_advance -= d;
+        pos[j].x_offset  -= d;
+        break;
+      case HB_DIRECTION_RTL:
+        d = roundf (exit_x) + pos[i].x_offset;
+        pos[i].x_advance -= d;
+        pos[i].x_offset  -= d;
+
+        pos[j].x_advance  = roundf (entry_x) + pos[j].x_offset;
+        break;
+      case HB_DIRECTION_TTB:
+        pos[i].y_advance  = roundf (exit_y) + pos[i].y_offset;
+
+        d = roundf (entry_y) + pos[j].y_offset;
+        pos[j].y_advance -= d;
+        pos[j].y_offset  -= d;
+        break;
+      case HB_DIRECTION_BTT:
+        d = roundf (exit_y) + pos[i].y_offset;
+        pos[i].y_advance -= d;
+        pos[i].y_offset  -= d;
+
+        pos[j].y_advance  = roundf (entry_y);
+        break;
+      case HB_DIRECTION_INVALID:
+      default:
+        break;
+    }
+
+    /* Cross-direction adjustment */
+
+    /* We attach child to parent (think graph theory and rooted trees whereas
+     * the root stays on baseline and each node aligns itself against its
+     * parent.
+     *
+     * Optimize things for the case of RightToLeft, as that's most common in
+     * Arabic. */
+    unsigned int child  = i;
+    unsigned int parent = j;
+    hb_position_t x_offset = entry_x - exit_x;
+    hb_position_t y_offset = entry_y - exit_y;
+    if  (!(c->lookup_props & LookupFlag::RightToLeft))
+    {
+      unsigned int k = child;
+      child = parent;
+      parent = k;
+      x_offset = -x_offset;
+      y_offset = -y_offset;
+    }
+
+    /* If child was already connected to someone else, walk through its old
+     * chain and reverse the link direction, such that the whole tree of its
+     * previous connection now attaches to new parent.  Watch out for case
+     * where new parent is on the path from old chain...
+     */
+    reverse_cursive_minor_offset (pos, child, c->direction, parent);
+
+    pos[child].attach_type() = ATTACH_TYPE_CURSIVE;
+    pos[child].attach_chain() = (int) parent - (int) child;
+    buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+    if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
+      pos[child].y_offset = y_offset;
+    else
+      pos[child].x_offset = x_offset;
+
+    /* If parent was attached to child, separate them.
+     * https://github.com/harfbuzz/harfbuzz/issues/2469
+     */
+    if (unlikely (pos[parent].attach_chain() == -pos[child].attach_chain()))
+    {
+      pos[parent].attach_chain() = 0;
+      if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
+	pos[parent].y_offset = 0;
+      else
+	pos[parent].x_offset = 0;
+    }
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "cursive attached glyph at %d to glyph at %d",
+			  i, j);
+    }
+
+    buffer->idx++;
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_subset_context_t *c,
+                  Iterator it,
+                  const void *src_base)
+  {
+    if (unlikely (!c->serializer->extend_min ((*this)))) return;
+    this->format = 1;
+    this->entryExitRecord.len = it.len ();
+
+    for (const EntryExitRecord& entry_record : + it
+                                               | hb_map (hb_second))
+      entry_record.subset (c, src_base);
+
+    auto glyphs =
+    + it
+    | hb_map_retains_sorting (hb_first)
+    ;
+
+    coverage.serialize_serialize (c->serializer, 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 (!out)) return_trace (false);
+
+    auto it =
+    + hb_zip (this+coverage, entryExitRecord)
+    | hb_filter (glyphset, hb_first)
+    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const EntryExitRecord&> p) -> hb_pair_t<hb_codepoint_t, const EntryExitRecord&>
+                              { return hb_pair (glyph_map[p.first], p.second);})
+    ;
+
+    bool ret = bool (it);
+    out->serialize (c, it, this);
+    return_trace (ret);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/ExtensionPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/ExtensionPos.hh
new file mode 100644
index 0000000000..d1808adab4
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/ExtensionPos.hh
@@ -0,0 +1,17 @@
+#ifndef OT_LAYOUT_GPOS_EXTENSIONPOS_HH
+#define OT_LAYOUT_GPOS_EXTENSIONPOS_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct ExtensionPos : Extension<ExtensionPos>
+{
+  typedef struct PosLookupSubTable SubTable;
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_EXTENSIONPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/GPOS.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/GPOS.hh
new file mode 100644
index 0000000000..9493ec987e
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/GPOS.hh
@@ -0,0 +1,171 @@
+#ifndef OT_LAYOUT_GPOS_GPOS_HH
+#define OT_LAYOUT_GPOS_GPOS_HH
+
+#include "../../../hb-ot-layout-common.hh"
+#include "../../../hb-ot-layout-gsubgpos.hh"
+#include "Common.hh"
+#include "PosLookup.hh"
+
+namespace OT {
+
+using Layout::GPOS_impl::PosLookup;
+
+namespace Layout {
+
+static void
+propagate_attachment_offsets (hb_glyph_position_t *pos,
+                              unsigned int len,
+                              unsigned int i,
+                              hb_direction_t direction,
+                              unsigned nesting_level = HB_MAX_NESTING_LEVEL);
+
+/*
+ * GPOS -- Glyph Positioning
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
+ */
+
+struct GPOS : GSUBGPOS
+{
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_GPOS;
+
+  using Lookup = PosLookup;
+
+  const PosLookup& get_lookup (unsigned int i) const
+  { return static_cast<const PosLookup &> (GSUBGPOS::get_lookup (i)); }
+
+  static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
+  static inline void position_finish_advances (hb_font_t *font, hb_buffer_t *buffer);
+  static inline void position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer);
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    hb_subset_layout_context_t l (c, tableTag);
+    return GSUBGPOS::subset<PosLookup> (&l);
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (GSUBGPOS::sanitize<PosLookup> (c));
+  }
+
+  HB_INTERNAL bool is_blocklisted (hb_blob_t *blob,
+                                   hb_face_t *face) const;
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    for (unsigned i = 0; i < GSUBGPOS::get_lookup_count (); i++)
+    {
+      if (!c->gpos_lookups->has (i)) continue;
+      const PosLookup &l = get_lookup (i);
+      l.dispatch (c);
+    }
+  }
+
+  void closure_lookups (hb_face_t      *face,
+                        const hb_set_t *glyphs,
+                        hb_set_t       *lookup_indexes /* IN/OUT */) const
+  { GSUBGPOS::closure_lookups<PosLookup> (face, glyphs, lookup_indexes); }
+
+  typedef GSUBGPOS::accelerator_t<GPOS> accelerator_t;
+};
+
+
+static void
+propagate_attachment_offsets (hb_glyph_position_t *pos,
+                              unsigned int len,
+                              unsigned int i,
+                              hb_direction_t direction,
+                              unsigned nesting_level)
+{
+  /* Adjusts offsets of attached glyphs (both cursive and mark) to accumulate
+   * offset of glyph they are attached to. */
+  int chain = pos[i].attach_chain(), type = pos[i].attach_type();
+  if (likely (!chain))
+    return;
+
+  pos[i].attach_chain() = 0;
+
+  unsigned int j = (int) i + chain;
+
+  if (unlikely (j >= len))
+    return;
+
+  if (unlikely (!nesting_level))
+    return;
+
+  propagate_attachment_offsets (pos, len, j, direction, nesting_level - 1);
+
+  assert (!!(type & GPOS_impl::ATTACH_TYPE_MARK) ^ !!(type & GPOS_impl::ATTACH_TYPE_CURSIVE));
+
+  if (type & GPOS_impl::ATTACH_TYPE_CURSIVE)
+  {
+    if (HB_DIRECTION_IS_HORIZONTAL (direction))
+      pos[i].y_offset += pos[j].y_offset;
+    else
+      pos[i].x_offset += pos[j].x_offset;
+  }
+  else /*if (type & GPOS_impl::ATTACH_TYPE_MARK)*/
+  {
+    pos[i].x_offset += pos[j].x_offset;
+    pos[i].y_offset += pos[j].y_offset;
+
+    assert (j < i);
+    if (HB_DIRECTION_IS_FORWARD (direction))
+      for (unsigned int k = j; k < i; k++) {
+        pos[i].x_offset -= pos[k].x_advance;
+        pos[i].y_offset -= pos[k].y_advance;
+      }
+    else
+      for (unsigned int k = j + 1; k < i + 1; k++) {
+        pos[i].x_offset += pos[k].x_advance;
+        pos[i].y_offset += pos[k].y_advance;
+      }
+  }
+}
+
+void
+GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
+{
+  unsigned int count = buffer->len;
+  for (unsigned int i = 0; i < count; i++)
+    buffer->pos[i].attach_chain() = buffer->pos[i].attach_type() = 0;
+}
+
+void
+GPOS::position_finish_advances (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
+{
+  //_hb_buffer_assert_gsubgpos_vars (buffer);
+}
+
+void
+GPOS::position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
+{
+  _hb_buffer_assert_gsubgpos_vars (buffer);
+
+  unsigned int len;
+  hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
+  hb_direction_t direction = buffer->props.direction;
+
+  /* Handle attachments */
+  if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT)
+    for (unsigned i = 0; i < len; i++)
+      propagate_attachment_offsets (pos, len, i, direction);
+
+  if (unlikely (font->slant))
+  {
+    for (unsigned i = 0; i < len; i++)
+      if (unlikely (pos[i].y_offset))
+        pos[i].x_offset += _hb_roundf (font->slant_xy * pos[i].y_offset);
+  }
+}
+
+}
+
+struct GPOS_accelerator_t : Layout::GPOS::accelerator_t {
+  GPOS_accelerator_t (hb_face_t *face) : Layout::GPOS::accelerator_t (face) {}
+};
+
+}
+
+#endif  /* OT_LAYOUT_GPOS_GPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/LigatureArray.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/LigatureArray.hh
new file mode 100644
index 0000000000..a2d807cc32
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/LigatureArray.hh
@@ -0,0 +1,56 @@
+#ifndef OT_LAYOUT_GPOS_LIGATUREARRAY_HH
+#define OT_LAYOUT_GPOS_LIGATUREARRAY_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+
+typedef AnchorMatrix LigatureAttach;    /* component-major--
+                                         * in order of writing direction--,
+                                         * mark-minor--
+                                         * ordered by class--zero-based. */
+
+/* Array of LigatureAttach tables ordered by LigatureCoverage Index */
+struct LigatureArray : List16OfOffset16To<LigatureAttach>
+{
+  template <typename Iterator,
+            hb_requires (hb_is_iterator (Iterator))>
+  bool subset (hb_subset_context_t *c,
+               Iterator             coverage,
+               unsigned             class_count,
+               const hb_map_t      *klass_mapping) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+
+    auto *out = c->serializer->start_embed (this);
+    if (unlikely (!c->serializer->extend_min (out)))  return_trace (false);
+
+    for (const auto _ : + hb_zip (coverage, *this)
+                  | hb_filter (glyphset, hb_first))
+    {
+      auto *matrix = out->serialize_append (c->serializer);
+      if (unlikely (!matrix)) return_trace (false);
+
+      const LigatureAttach& src = (this + _.second);
+      auto indexes =
+          + hb_range (src.rows * class_count)
+          | hb_filter ([=] (unsigned index) { return klass_mapping->has (index % class_count); })
+          ;
+      matrix->serialize_subset (c,
+                                _.second,
+                                this,
+                                src.rows,
+                                indexes);
+    }
+    return_trace (this->len);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_LIGATUREARRAY_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkArray.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkArray.hh
new file mode 100644
index 0000000000..cb5e8b2689
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkArray.hh
@@ -0,0 +1,128 @@
+#ifndef OT_LAYOUT_GPOS_MARKARRAY_HH
+#define OT_LAYOUT_GPOS_MARKARRAY_HH
+
+#include "AnchorMatrix.hh"
+#include "MarkRecord.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct MarkArray : Array16Of<MarkRecord>        /* Array of MarkRecords--in Coverage order */
+{
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (Array16Of<MarkRecord>::sanitize (c, this));
+  }
+
+  bool apply (hb_ot_apply_context_t *c,
+              unsigned int mark_index, unsigned int glyph_index,
+              const AnchorMatrix &anchors, unsigned int class_count,
+              unsigned int glyph_pos) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    const MarkRecord &record = Array16Of<MarkRecord>::operator[](mark_index);
+    unsigned int mark_class = record.klass;
+
+    const Anchor& mark_anchor = this + record.markAnchor;
+    bool found;
+    const Anchor& glyph_anchor = anchors.get_anchor (glyph_index, mark_class, class_count, &found);
+    /* If this subtable doesn't have an anchor for this base and this class,
+     * return false such that the subsequent subtables have a chance at it. */
+    if (unlikely (!found)) return_trace (false);
+
+    float mark_x, mark_y, base_x, base_y;
+
+    buffer->unsafe_to_break (glyph_pos, buffer->idx + 1);
+    mark_anchor.get_anchor (c, buffer->cur().codepoint, &mark_x, &mark_y);
+    glyph_anchor.get_anchor (c, buffer->info[glyph_pos].codepoint, &base_x, &base_y);
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "attaching mark glyph at %d to glyph at %d",
+			  c->buffer->idx, glyph_pos);
+    }
+
+    hb_glyph_position_t &o = buffer->cur_pos();
+    o.x_offset = roundf (base_x - mark_x);
+    o.y_offset = roundf (base_y - mark_y);
+    o.attach_type() = ATTACH_TYPE_MARK;
+    o.attach_chain() = (int) glyph_pos - (int) buffer->idx;
+    buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "attached mark glyph at %d to glyph at %d",
+			  c->buffer->idx, glyph_pos);
+    }
+
+    buffer->idx++;
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+      hb_requires (hb_is_iterator (Iterator))>
+  bool subset (hb_subset_context_t *c,
+               Iterator             coverage,
+               const hb_map_t      *klass_mapping) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+
+    auto* out = c->serializer->start_embed (this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+
+    auto mark_iter =
+    + hb_zip (coverage, this->iter ())
+    | hb_filter (glyphset, hb_first)
+    | hb_map (hb_second)
+    ;
+
+    unsigned new_length = 0;
+    for (const auto& mark_record : mark_iter) {
+      if (unlikely (!mark_record.subset (c, this, klass_mapping)))
+        return_trace (false);
+      new_length++;
+    }
+
+    if (unlikely (!c->serializer->check_assign (out->len, new_length,
+                                                HB_SERIALIZE_ERROR_ARRAY_OVERFLOW)))
+      return_trace (false);
+
+    return_trace (true);
+  }
+};
+
+HB_INTERNAL inline
+void Markclass_closure_and_remap_indexes (const Coverage  &mark_coverage,
+                                          const MarkArray &mark_array,
+                                          const hb_set_t  &glyphset,
+                                          hb_map_t*        klass_mapping /* INOUT */)
+{
+  hb_set_t orig_classes;
+
+  + hb_zip (mark_coverage, mark_array)
+  | hb_filter (glyphset, hb_first)
+  | hb_map (hb_second)
+  | hb_map (&MarkRecord::get_class)
+  | hb_sink (orig_classes)
+  ;
+
+  unsigned idx = 0;
+  for (auto klass : orig_classes.iter ())
+  {
+    if (klass_mapping->has (klass)) continue;
+    klass_mapping->set (klass, idx);
+    idx++;
+  }
+}
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKARRAY_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePos.hh
new file mode 100644
index 0000000000..edf7099c07
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePos.hh
@@ -0,0 +1,41 @@
+#ifndef OT_LAYOUT_GPOS_MARKBASEPOS_HH
+#define OT_LAYOUT_GPOS_MARKBASEPOS_HH
+
+#include "MarkBasePosFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct MarkBasePos
+{
+  protected:
+  union {
+  HBUINT16				format;         /* Format identifier */
+  MarkBasePosFormat1_2<SmallTypes>	format1;
+#ifndef HB_NO_BEYOND_64K
+  MarkBasePosFormat1_2<MediumTypes>	format2;
+#endif
+  } 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)...));
+#ifndef HB_NO_BEYOND_64K
+    case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+#endif
+    default:return_trace (c->default_return_value ());
+    }
+  }
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKBASEPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePosFormat1.hh
new file mode 100644
index 0000000000..ebb8c31c67
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkBasePosFormat1.hh
@@ -0,0 +1,219 @@
+#ifndef OT_LAYOUT_GPOS_MARKBASEPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_MARKBASEPOSFORMAT1_HH
+
+#include "MarkArray.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+typedef AnchorMatrix BaseArray;         /* base-major--
+                                         * in order of BaseCoverage Index--,
+                                         * mark-minor--
+                                         * ordered by class--zero-based. */
+
+template <typename Types>
+struct MarkBasePosFormat1_2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  typename Types::template OffsetTo<Coverage>
+                markCoverage;           /* Offset to MarkCoverage table--from
+                                         * beginning of MarkBasePos subtable */
+  typename Types::template OffsetTo<Coverage>
+                baseCoverage;           /* Offset to BaseCoverage table--from
+                                         * beginning of MarkBasePos subtable */
+  HBUINT16      classCount;             /* Number of classes defined for marks */
+  typename Types::template OffsetTo<MarkArray>
+                markArray;              /* Offset to MarkArray table--from
+                                         * beginning of MarkBasePos subtable */
+  typename Types::template OffsetTo<BaseArray>
+                baseArray;              /* Offset to BaseArray table--from
+                                         * beginning of MarkBasePos subtable */
+
+  public:
+  DEFINE_SIZE_STATIC (4 + 4 * Types::size);
+
+    bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+                  markCoverage.sanitize (c, this) &&
+                  baseCoverage.sanitize (c, this) &&
+                  markArray.sanitize (c, this) &&
+                  baseArray.sanitize (c, this, (unsigned int) classCount));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return (this+markCoverage).intersects (glyphs) &&
+           (this+baseCoverage).intersects (glyphs);
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    + hb_zip (this+markCoverage, this+markArray)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    | hb_apply ([&] (const MarkRecord& record) { record.collect_variation_indices (c, &(this+markArray)); })
+    ;
+
+    hb_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+markCoverage, this+markArray, *c->glyph_set, &klass_mapping);
+
+    unsigned basecount = (this+baseArray).rows;
+    auto base_iter =
+    + hb_zip (this+baseCoverage, hb_range (basecount))
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    ;
+
+    hb_sorted_vector_t<unsigned> base_indexes;
+    for (const unsigned row : base_iter)
+    {
+      + hb_range ((unsigned) classCount)
+      | hb_filter (klass_mapping)
+      | hb_map ([&] (const unsigned col) { return row * (unsigned) classCount + col; })
+      | hb_sink (base_indexes)
+      ;
+    }
+    (this+baseArray).collect_variation_indices (c, base_indexes.iter ());
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+markCoverage).collect_coverage (c->input))) return;
+    if (unlikely (!(this+baseCoverage).collect_coverage (c->input))) return;
+  }
+
+  const Coverage &get_coverage () const { return this+markCoverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (mark_index == NOT_COVERED)) return_trace (false);
+
+    /* Now we search backwards for a non-mark glyph */
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
+    do {
+      unsigned unsafe_from;
+      if (!skippy_iter.prev (&unsafe_from))
+      {
+        buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+        return_trace (false);
+      }
+
+      /* We only want to attach to the first of a MultipleSubst sequence.
+       * https://github.com/harfbuzz/harfbuzz/issues/740
+       * Reject others...
+       * ...but stop if we find a mark in the MultipleSubst sequence:
+       * https://github.com/harfbuzz/harfbuzz/issues/1020 */
+      if (!_hb_glyph_info_multiplied (&buffer->info[skippy_iter.idx]) ||
+          0 == _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) ||
+          (skippy_iter.idx == 0 ||
+           _hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx - 1]) ||
+           !_hb_glyph_info_multiplied (&buffer->info[skippy_iter.idx - 1]) ||
+           _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx]) !=
+           _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx - 1]) ||
+           _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) !=
+           _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx - 1]) + 1
+           ))
+        break;
+      skippy_iter.reject ();
+    } while (true);
+
+    /* Checking that matched glyph is actually a base glyph by GDEF is too strong; disabled */
+    //if (!_hb_glyph_info_is_base_glyph (&buffer->info[skippy_iter.idx])) { return_trace (false); }
+
+    unsigned int base_index = (this+baseCoverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint);
+    if (base_index == NOT_COVERED)
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    return_trace ((this+markArray).apply (c, mark_index, base_index, this+baseArray, classCount, skippy_iter.idx));
+  }
+
+  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_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+markCoverage, this+markArray, glyphset, &klass_mapping);
+
+    if (!klass_mapping.get_population ()) return_trace (false);
+    out->classCount = klass_mapping.get_population ();
+
+    auto mark_iter =
+    + hb_zip (this+markCoverage, this+markArray)
+    | hb_filter (glyphset, hb_first)
+    ;
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+    + mark_iter
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+
+    if (!out->markCoverage.serialize_serialize (c->serializer, new_coverage.iter ()))
+      return_trace (false);
+
+    out->markArray.serialize_subset (c, markArray, this,
+                                     (this+markCoverage).iter (),
+                                     &klass_mapping);
+
+    unsigned basecount = (this+baseArray).rows;
+    auto base_iter =
+    + hb_zip (this+baseCoverage, hb_range (basecount))
+    | hb_filter (glyphset, hb_first)
+    ;
+
+    new_coverage.reset ();
+    + base_iter
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+
+    if (!out->baseCoverage.serialize_serialize (c->serializer, new_coverage.iter ()))
+      return_trace (false);
+
+    hb_sorted_vector_t<unsigned> base_indexes;
+    for (const unsigned row : + base_iter
+                              | hb_map (hb_second))
+    {
+      + hb_range ((unsigned) classCount)
+      | hb_filter (klass_mapping)
+      | hb_map ([&] (const unsigned col) { return row * (unsigned) classCount + col; })
+      | hb_sink (base_indexes)
+      ;
+    }
+
+    out->baseArray.serialize_subset (c, baseArray, this,
+                                     base_iter.len (),
+                                     base_indexes.iter ());
+
+    return_trace (true);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKBASEPOSFORMAT1_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPos.hh
new file mode 100644
index 0000000000..09152fd876
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPos.hh
@@ -0,0 +1,41 @@
+#ifndef OT_LAYOUT_GPOS_MARKLIGPOS_HH
+#define OT_LAYOUT_GPOS_MARKLIGPOS_HH
+
+#include "MarkLigPosFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct MarkLigPos
+{
+  protected:
+  union {
+  HBUINT16				format;         /* Format identifier */
+  MarkLigPosFormat1_2<SmallTypes>	format1;
+#ifndef HB_NO_BEYOND_64K
+  MarkLigPosFormat1_2<MediumTypes>	format2;
+#endif
+  } 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)...));
+#ifndef HB_NO_BEYOND_64K
+    case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+#endif
+    default:return_trace (c->default_return_value ());
+    }
+  }
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKLIGPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPosFormat1.hh
new file mode 100644
index 0000000000..1a8021237e
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkLigPosFormat1.hh
@@ -0,0 +1,206 @@
+#ifndef OT_LAYOUT_GPOS_MARKLIGPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_MARKLIGPOSFORMAT1_HH
+
+#include "LigatureArray.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+
+template <typename Types>
+struct MarkLigPosFormat1_2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  typename Types::template OffsetTo<Coverage>
+                markCoverage;           /* Offset to Mark Coverage table--from
+                                         * beginning of MarkLigPos subtable */
+  typename Types::template OffsetTo<Coverage>
+                ligatureCoverage;       /* Offset to Ligature Coverage
+                                         * table--from beginning of MarkLigPos
+                                         * subtable */
+  HBUINT16      classCount;             /* Number of defined mark classes */
+  typename Types::template OffsetTo<MarkArray>
+                markArray;              /* Offset to MarkArray table--from
+                                         * beginning of MarkLigPos subtable */
+  typename Types::template OffsetTo<LigatureArray>
+                ligatureArray;          /* Offset to LigatureArray table--from
+                                         * beginning of MarkLigPos subtable */
+  public:
+  DEFINE_SIZE_STATIC (4 + 4 * Types::size);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+                  markCoverage.sanitize (c, this) &&
+                  ligatureCoverage.sanitize (c, this) &&
+                  markArray.sanitize (c, this) &&
+                  ligatureArray.sanitize (c, this, (unsigned int) classCount));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return (this+markCoverage).intersects (glyphs) &&
+           (this+ligatureCoverage).intersects (glyphs);
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    + hb_zip (this+markCoverage, this+markArray)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    | hb_apply ([&] (const MarkRecord& record) { record.collect_variation_indices (c, &(this+markArray)); })
+    ;
+
+    hb_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+markCoverage, this+markArray, *c->glyph_set, &klass_mapping);
+
+    unsigned ligcount = (this+ligatureArray).len;
+    auto lig_iter =
+    + hb_zip (this+ligatureCoverage, hb_range (ligcount))
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    ;
+
+    const LigatureArray& lig_array = this+ligatureArray;
+    for (const unsigned i : lig_iter)
+    {
+      hb_sorted_vector_t<unsigned> lig_indexes;
+      unsigned row_count = lig_array[i].rows;
+      for (unsigned row : + hb_range (row_count))
+      {
+        + hb_range ((unsigned) classCount)
+        | hb_filter (klass_mapping)
+        | hb_map ([&] (const unsigned col) { return row * (unsigned) classCount + col; })
+        | hb_sink (lig_indexes)
+        ;
+      }
+
+      lig_array[i].collect_variation_indices (c, lig_indexes.iter ());
+    }
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+markCoverage).collect_coverage (c->input))) return;
+    if (unlikely (!(this+ligatureCoverage).collect_coverage (c->input))) return;
+  }
+
+  const Coverage &get_coverage () const { return this+markCoverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (mark_index == NOT_COVERED)) return_trace (false);
+
+    /* Now we search backwards for a non-mark glyph */
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
+    unsigned unsafe_from;
+    if (!skippy_iter.prev (&unsafe_from))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    /* Checking that matched glyph is actually a ligature by GDEF is too strong; disabled */
+    //if (!_hb_glyph_info_is_ligature (&buffer->info[skippy_iter.idx])) { return_trace (false); }
+
+    unsigned int j = skippy_iter.idx;
+    unsigned int lig_index = (this+ligatureCoverage).get_coverage  (buffer->info[j].codepoint);
+    if (lig_index == NOT_COVERED)
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    const LigatureArray& lig_array = this+ligatureArray;
+    const LigatureAttach& lig_attach = lig_array[lig_index];
+
+    /* Find component to attach to */
+    unsigned int comp_count = lig_attach.rows;
+    if (unlikely (!comp_count))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    /* We must now check whether the ligature ID of the current mark glyph
+     * is identical to the ligature ID of the found ligature.  If yes, we
+     * can directly use the component index.  If not, we attach the mark
+     * glyph to the last component of the ligature. */
+    unsigned int comp_index;
+    unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[j]);
+    unsigned int mark_id = _hb_glyph_info_get_lig_id (&buffer->cur());
+    unsigned int mark_comp = _hb_glyph_info_get_lig_comp (&buffer->cur());
+    if (lig_id && lig_id == mark_id && mark_comp > 0)
+      comp_index = hb_min (comp_count, _hb_glyph_info_get_lig_comp (&buffer->cur())) - 1;
+    else
+      comp_index = comp_count - 1;
+
+    return_trace ((this+markArray).apply (c, mark_index, comp_index, lig_attach, classCount, j));
+  }
+
+  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_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+markCoverage, this+markArray, glyphset, &klass_mapping);
+
+    if (!klass_mapping.get_population ()) return_trace (false);
+    out->classCount = klass_mapping.get_population ();
+
+    auto mark_iter =
+    + hb_zip (this+markCoverage, this+markArray)
+    | hb_filter (glyphset, hb_first)
+    ;
+
+    auto new_mark_coverage =
+    + mark_iter
+    | hb_map_retains_sorting (hb_first)
+    | hb_map_retains_sorting (glyph_map)
+    ;
+
+    if (!out->markCoverage.serialize_serialize (c->serializer, new_mark_coverage))
+      return_trace (false);
+
+    out->markArray.serialize_subset (c, markArray, this,
+                                     (this+markCoverage).iter (),
+                                     &klass_mapping);
+
+    auto new_ligature_coverage =
+    + hb_iter (this + ligatureCoverage)
+    | hb_filter (glyphset)
+    | hb_map_retains_sorting (glyph_map)
+    ;
+
+    if (!out->ligatureCoverage.serialize_serialize (c->serializer, new_ligature_coverage))
+      return_trace (false);
+
+    out->ligatureArray.serialize_subset (c, ligatureArray, this,
+                                         hb_iter (this+ligatureCoverage), classCount, &klass_mapping);
+
+    return_trace (true);
+  }
+
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKLIGPOSFORMAT1_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPos.hh
new file mode 100644
index 0000000000..4118fc304f
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPos.hh
@@ -0,0 +1,42 @@
+#ifndef OT_LAYOUT_GPOS_MARKMARKPOS_HH
+#define OT_LAYOUT_GPOS_MARKMARKPOS_HH
+
+#include "MarkMarkPosFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct MarkMarkPos
+{
+  protected:
+  union {
+  HBUINT16				format;         /* Format identifier */
+  MarkMarkPosFormat1_2<SmallTypes>	format1;
+#ifndef HB_NO_BEYOND_64K
+  MarkMarkPosFormat1_2<MediumTypes>	format2;
+#endif
+  } 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)...));
+#ifndef HB_NO_BEYOND_64K
+    case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+#endif
+    default:return_trace (c->default_return_value ());
+    }
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKMARKPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPosFormat1.hh
new file mode 100644
index 0000000000..fbcebb8044
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkMarkPosFormat1.hh
@@ -0,0 +1,228 @@
+#ifndef OT_LAYOUT_GPOS_MARKMARKPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_MARKMARKPOSFORMAT1_HH
+
+#include "MarkMarkPosFormat1.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+typedef AnchorMatrix Mark2Array;        /* mark2-major--
+                                         * in order of Mark2Coverage Index--,
+                                         * mark1-minor--
+                                         * ordered by class--zero-based. */
+
+template <typename Types>
+struct MarkMarkPosFormat1_2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  typename Types::template OffsetTo<Coverage>
+                mark1Coverage;          /* Offset to Combining Mark1 Coverage
+                                         * table--from beginning of MarkMarkPos
+                                         * subtable */
+  typename Types::template OffsetTo<Coverage>
+                mark2Coverage;          /* Offset to Combining Mark2 Coverage
+                                         * table--from beginning of MarkMarkPos
+                                         * subtable */
+  HBUINT16      classCount;             /* Number of defined mark classes */
+  typename Types::template OffsetTo<MarkArray>
+                mark1Array;             /* Offset to Mark1Array table--from
+                                         * beginning of MarkMarkPos subtable */
+  typename Types::template OffsetTo<Mark2Array>
+                mark2Array;             /* Offset to Mark2Array table--from
+                                         * beginning of MarkMarkPos subtable */
+  public:
+  DEFINE_SIZE_STATIC (4 + 4 * Types::size);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+                  mark1Coverage.sanitize (c, this) &&
+                  mark2Coverage.sanitize (c, this) &&
+                  mark1Array.sanitize (c, this) &&
+                  mark2Array.sanitize (c, this, (unsigned int) classCount));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return (this+mark1Coverage).intersects (glyphs) &&
+           (this+mark2Coverage).intersects (glyphs);
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    + hb_zip (this+mark1Coverage, this+mark1Array)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    | hb_apply ([&] (const MarkRecord& record) { record.collect_variation_indices (c, &(this+mark1Array)); })
+    ;
+
+    hb_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+mark1Coverage, this+mark1Array, *c->glyph_set, &klass_mapping);
+
+    unsigned mark2_count = (this+mark2Array).rows;
+    auto mark2_iter =
+    + hb_zip (this+mark2Coverage, hb_range (mark2_count))
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    ;
+
+    hb_sorted_vector_t<unsigned> mark2_indexes;
+    for (const unsigned row : mark2_iter)
+    {
+      + hb_range ((unsigned) classCount)
+      | hb_filter (klass_mapping)
+      | hb_map ([&] (const unsigned col) { return row * (unsigned) classCount + col; })
+      | hb_sink (mark2_indexes)
+      ;
+    }
+    (this+mark2Array).collect_variation_indices (c, mark2_indexes.iter ());
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+mark1Coverage).collect_coverage (c->input))) return;
+    if (unlikely (!(this+mark2Coverage).collect_coverage (c->input))) return;
+  }
+
+  const Coverage &get_coverage () const { return this+mark1Coverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int mark1_index = (this+mark1Coverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (mark1_index == NOT_COVERED)) return_trace (false);
+
+    /* now we search backwards for a suitable mark glyph until a non-mark glyph */
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    skippy_iter.set_lookup_props (c->lookup_props & ~(uint32_t)LookupFlag::IgnoreFlags);
+    unsigned unsafe_from;
+    if (!skippy_iter.prev (&unsafe_from))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    if (!_hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx]))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    unsigned int j = skippy_iter.idx;
+
+    unsigned int id1 = _hb_glyph_info_get_lig_id (&buffer->cur());
+    unsigned int id2 = _hb_glyph_info_get_lig_id (&buffer->info[j]);
+    unsigned int comp1 = _hb_glyph_info_get_lig_comp (&buffer->cur());
+    unsigned int comp2 = _hb_glyph_info_get_lig_comp (&buffer->info[j]);
+
+    if (likely (id1 == id2))
+    {
+      if (id1 == 0) /* Marks belonging to the same base. */
+        goto good;
+      else if (comp1 == comp2) /* Marks belonging to the same ligature component. */
+        goto good;
+    }
+    else
+    {
+      /* If ligature ids don't match, it may be the case that one of the marks
+       * itself is a ligature.  In which case match. */
+      if ((id1 > 0 && !comp1) || (id2 > 0 && !comp2))
+        goto good;
+    }
+
+    /* Didn't match. */
+    buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+    return_trace (false);
+
+    good:
+    unsigned int mark2_index = (this+mark2Coverage).get_coverage  (buffer->info[j].codepoint);
+    if (mark2_index == NOT_COVERED)
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    return_trace ((this+mark1Array).apply (c, mark1_index, mark2_index, this+mark2Array, classCount, j));
+  }
+
+  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_map_t klass_mapping;
+    Markclass_closure_and_remap_indexes (this+mark1Coverage, this+mark1Array, glyphset, &klass_mapping);
+
+    if (!klass_mapping.get_population ()) return_trace (false);
+    out->classCount = klass_mapping.get_population ();
+
+    auto mark1_iter =
+    + hb_zip (this+mark1Coverage, this+mark1Array)
+    | hb_filter (glyphset, hb_first)
+    ;
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+    + mark1_iter
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+
+    if (!out->mark1Coverage.serialize_serialize (c->serializer, new_coverage.iter ()))
+      return_trace (false);
+
+    out->mark1Array.serialize_subset (c, mark1Array, this,
+                                      (this+mark1Coverage).iter (),
+                                      &klass_mapping);
+
+    unsigned mark2count = (this+mark2Array).rows;
+    auto mark2_iter =
+    + hb_zip (this+mark2Coverage, hb_range (mark2count))
+    | hb_filter (glyphset, hb_first)
+    ;
+
+    new_coverage.reset ();
+    + mark2_iter
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+
+    if (!out->mark2Coverage.serialize_serialize (c->serializer, new_coverage.iter ()))
+      return_trace (false);
+
+    hb_sorted_vector_t<unsigned> mark2_indexes;
+    for (const unsigned row : + mark2_iter
+                              | hb_map (hb_second))
+    {
+      + hb_range ((unsigned) classCount)
+      | hb_filter (klass_mapping)
+      | hb_map ([&] (const unsigned col) { return row * (unsigned) classCount + col; })
+      | hb_sink (mark2_indexes)
+      ;
+    }
+
+    out->mark2Array.serialize_subset (c, mark2Array, this, mark2_iter.len (), mark2_indexes.iter ());
+
+    return_trace (true);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKMARKPOSFORMAT1_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/MarkRecord.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkRecord.hh
new file mode 100644
index 0000000000..a7d489d2a5
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/MarkRecord.hh
@@ -0,0 +1,52 @@
+#ifndef OT_LAYOUT_GPOS_MARKRECORD_HH
+#define OT_LAYOUT_GPOS_MARKRECORD_HH
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct MarkRecord
+{
+  friend struct MarkArray;
+
+  public:
+  HBUINT16      klass;                  /* Class defined for this mark */
+  Offset16To<Anchor>
+                markAnchor;             /* Offset to Anchor table--from
+                                         * beginning of MarkArray table */
+  public:
+  DEFINE_SIZE_STATIC (4);
+
+  unsigned get_class () const { return (unsigned) klass; }
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && markAnchor.sanitize (c, base));
+  }
+
+  MarkRecord *subset (hb_subset_context_t    *c,
+                      const void             *src_base,
+                      const hb_map_t         *klass_mapping) const
+  {
+    TRACE_SUBSET (this);
+    auto *out = c->serializer->embed (this);
+    if (unlikely (!out)) return_trace (nullptr);
+
+    out->klass = klass_mapping->get (klass);
+    out->markAnchor.serialize_subset (c, markAnchor, src_base);
+    return_trace (out);
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const void *src_base) const
+  {
+    (src_base+markAnchor).collect_variation_indices (c);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_MARKRECORD_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PairPos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPos.hh
new file mode 100644
index 0000000000..9823768cbc
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPos.hh
@@ -0,0 +1,46 @@
+#ifndef OT_LAYOUT_GPOS_PAIRPOS_HH
+#define OT_LAYOUT_GPOS_PAIRPOS_HH
+
+#include "PairPosFormat1.hh"
+#include "PairPosFormat2.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct PairPos
+{
+  protected:
+  union {
+  HBUINT16			format;         /* Format identifier */
+  PairPosFormat1_3<SmallTypes>	format1;
+  PairPosFormat2_4<SmallTypes>	format2;
+#ifndef HB_NO_BEYOND_64K
+  PairPosFormat1_3<MediumTypes>	format3;
+  PairPosFormat2_4<MediumTypes>	format4;
+#endif
+  } 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)...));
+#ifndef HB_NO_BEYOND_64K
+    case 3: return_trace (c->dispatch (u.format3, std::forward<Ts> (ds)...));
+    case 4: return_trace (c->dispatch (u.format4, std::forward<Ts> (ds)...));
+#endif
+    default:return_trace (c->default_return_value ());
+    }
+  }
+};
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_PAIRPOS_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat1.hh
new file mode 100644
index 0000000000..9c9b268889
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat1.hh
@@ -0,0 +1,219 @@
+#ifndef OT_LAYOUT_GPOS_PAIRPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_PAIRPOSFORMAT1_HH
+
+#include "PairSet.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+
+template <typename Types>
+struct PairPosFormat1_3
+{
+  using PairSet = GPOS_impl::PairSet<Types>;
+  using PairValueRecord = GPOS_impl::PairValueRecord<Types>;
+
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  typename Types::template OffsetTo<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  ValueFormat   valueFormat[2];         /* [0] Defines the types of data in
+                                         * ValueRecord1--for the first glyph
+                                         * in the pair--may be zero (0) */
+                                        /* [1] Defines the types of data in
+                                         * ValueRecord2--for the second glyph
+                                         * in the pair--may be zero (0) */
+  Array16Of<typename Types::template OffsetTo<PairSet>>
+                pairSet;                /* Array of PairSet tables
+                                         * ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_ARRAY (8 + Types::size, pairSet);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+
+    if (!c->check_struct (this)) return_trace (false);
+
+    unsigned int len1 = valueFormat[0].get_len ();
+    unsigned int len2 = valueFormat[1].get_len ();
+    typename PairSet::sanitize_closure_t closure =
+    {
+      valueFormat,
+      len1,
+      1 + len1 + len2
+    };
+
+    return_trace (coverage.sanitize (c, this) && pairSet.sanitize (c, this, &closure));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    auto &cov = this+coverage;
+
+    if (pairSet.len > glyphs->get_population () * hb_bit_storage ((unsigned) pairSet.len) / 4)
+    {
+      for (hb_codepoint_t g = HB_SET_VALUE_INVALID; glyphs->next (&g);)
+      {
+	unsigned i = cov.get_coverage (g);
+	if ((this+pairSet[i]).intersects (glyphs, valueFormat))
+	  return true;
+      }
+      return false;
+    }
+
+    return
+    + hb_zip (cov, pairSet)
+    | hb_filter (*glyphs, hb_first)
+    | hb_map (hb_second)
+    | hb_map ([glyphs, this] (const typename Types::template OffsetTo<PairSet> &_)
+              { return (this+_).intersects (glyphs, valueFormat); })
+    | hb_any
+    ;
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    if ((!valueFormat[0].has_device ()) && (!valueFormat[1].has_device ())) return;
+
+    auto it =
+    + hb_zip (this+coverage, pairSet)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    ;
+
+    if (!it) return;
+    + it
+    | hb_map (hb_add (this))
+    | hb_apply ([&] (const PairSet& _) { _.collect_variation_indices (c, valueFormat); })
+    ;
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    unsigned int count = pairSet.len;
+    for (unsigned int i = 0; i < count; i++)
+      (this+pairSet[i]).collect_glyphs (c, valueFormat);
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (index == NOT_COVERED)) return_trace (false);
+
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    unsigned unsafe_to;
+    if (!skippy_iter.next (&unsafe_to))
+    {
+      buffer->unsafe_to_concat (buffer->idx, unsafe_to);
+      return_trace (false);
+    }
+
+    return_trace ((this+pairSet[index]).apply (c, valueFormat, skippy_iter.idx));
+  }
+
+  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;
+    out->valueFormat[0] = valueFormat[0];
+    out->valueFormat[1] = valueFormat[1];
+    if (c->plan->flags & HB_SUBSET_FLAGS_NO_HINTING)
+    {
+      hb_pair_t<unsigned, unsigned> newFormats = compute_effective_value_formats (glyphset);
+      out->valueFormat[0] = newFormats.first;
+      out->valueFormat[1] = newFormats.second;
+    }
+
+    if (c->plan->all_axes_pinned)
+    {
+      out->valueFormat[0] = out->valueFormat[0].drop_device_table_flags ();
+      out->valueFormat[1] = out->valueFormat[1].drop_device_table_flags ();
+    }
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+
+    + hb_zip (this+coverage, pairSet)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter ([this, c, out] (const typename Types::template OffsetTo<PairSet>& _)
+                 {
+                   auto snap = c->serializer->snapshot ();
+                   auto *o = out->pairSet.serialize_append (c->serializer);
+                   if (unlikely (!o)) return false;
+                   bool ret = o->serialize_subset (c, _, this, valueFormat, out->valueFormat);
+                   if (!ret)
+                   {
+                     out->pairSet.pop ();
+                     c->serializer->revert (snap);
+                   }
+                   return ret;
+                 },
+                 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));
+  }
+
+
+  hb_pair_t<unsigned, unsigned> compute_effective_value_formats (const hb_set_t& glyphset) const
+  {
+    unsigned len1 = valueFormat[0].get_len ();
+    unsigned len2 = valueFormat[1].get_len ();
+    unsigned record_size = HBUINT16::static_size + Value::static_size * (len1 + len2);
+
+    unsigned format1 = 0;
+    unsigned format2 = 0;
+    for (const auto & _ :
+	  + hb_zip (this+coverage, pairSet)
+	  | hb_filter (glyphset, hb_first)
+	  | hb_map (hb_second)
+	)
+    {
+      const PairSet& set = (this + _);
+      const PairValueRecord *record = &set.firstPairValueRecord;
+
+      unsigned count = set.len;
+      for (unsigned i = 0; i < count; i++)
+      {
+        if (record->intersects (glyphset))
+        {
+          format1 = format1 | valueFormat[0].get_effective_format (record->get_values_1 ());
+          format2 = format2 | valueFormat[1].get_effective_format (record->get_values_2 (valueFormat[0]));
+        }
+        record = &StructAtOffset<const PairValueRecord> (record, record_size);
+      }
+
+      if (format1 == valueFormat[0] && format2 == valueFormat[1])
+        break;
+    }
+
+    return hb_pair (format1, format2);
+  }
+};
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_PAIRPOSFORMAT1_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat2.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat2.hh
new file mode 100644
index 0000000000..9c87ac2b03
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PairPosFormat2.hh
@@ -0,0 +1,351 @@
+#ifndef OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
+#define OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
+
+#include "ValueFormat.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+template <typename Types>
+struct PairPosFormat2_4
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 2 */
+  typename Types::template OffsetTo<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  ValueFormat   valueFormat1;           /* ValueRecord definition--for the
+                                         * first glyph of the pair--may be zero
+                                         * (0) */
+  ValueFormat   valueFormat2;           /* ValueRecord definition--for the
+                                         * second glyph of the pair--may be
+                                         * zero (0) */
+  typename Types::template OffsetTo<ClassDef>
+                classDef1;              /* Offset to ClassDef table--from
+                                         * beginning of PairPos subtable--for
+                                         * the first glyph of the pair */
+  typename Types::template OffsetTo<ClassDef>
+                classDef2;              /* Offset to ClassDef table--from
+                                         * beginning of PairPos subtable--for
+                                         * the second glyph of the pair */
+  HBUINT16      class1Count;            /* Number of classes in ClassDef1
+                                         * table--includes Class0 */
+  HBUINT16      class2Count;            /* Number of classes in ClassDef2
+                                         * table--includes Class0 */
+  ValueRecord   values;                 /* Matrix of value pairs:
+                                         * class1-major, class2-minor,
+                                         * Each entry has value1 and value2 */
+  public:
+  DEFINE_SIZE_ARRAY (10 + 3 * Types::size, values);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    if (!(c->check_struct (this)
+       && coverage.sanitize (c, this)
+       && classDef1.sanitize (c, this)
+       && classDef2.sanitize (c, this))) return_trace (false);
+
+    unsigned int len1 = valueFormat1.get_len ();
+    unsigned int len2 = valueFormat2.get_len ();
+    unsigned int stride = len1 + len2;
+    unsigned int record_size = valueFormat1.get_size () + valueFormat2.get_size ();
+    unsigned int count = (unsigned int) class1Count * (unsigned int) class2Count;
+    return_trace (c->check_range ((const void *) values,
+                                  count,
+                                  record_size) &&
+                  valueFormat1.sanitize_values_stride_unsafe (c, this, &values[0], count, stride) &&
+                  valueFormat2.sanitize_values_stride_unsafe (c, this, &values[len1], count, stride));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  {
+    return (this+coverage).intersects (glyphs) &&
+           (this+classDef2).intersects (glyphs);
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    if (!intersects (c->glyph_set)) return;
+    if ((!valueFormat1.has_device ()) && (!valueFormat2.has_device ())) return;
+
+    hb_set_t klass1_glyphs, klass2_glyphs;
+    if (!(this+classDef1).collect_coverage (&klass1_glyphs)) return;
+    if (!(this+classDef2).collect_coverage (&klass2_glyphs)) return;
+
+    hb_set_t class1_set, class2_set;
+    for (const unsigned cp : + c->glyph_set->iter () | hb_filter (this + coverage))
+    {
+      if (!klass1_glyphs.has (cp)) class1_set.add (0);
+      else
+      {
+        unsigned klass1 = (this+classDef1).get (cp);
+        class1_set.add (klass1);
+      }
+    }
+
+    class2_set.add (0);
+    for (const unsigned cp : + c->glyph_set->iter () | hb_filter (klass2_glyphs))
+    {
+      unsigned klass2 = (this+classDef2).get (cp);
+      class2_set.add (klass2);
+    }
+
+    if (class1_set.is_empty ()
+        || class2_set.is_empty ()
+        || (class2_set.get_population() == 1 && class2_set.has(0)))
+      return;
+
+    unsigned len1 = valueFormat1.get_len ();
+    unsigned len2 = valueFormat2.get_len ();
+    const hb_array_t<const Value> values_array = values.as_array ((unsigned)class1Count * (unsigned) class2Count * (len1 + len2));
+    for (const unsigned class1_idx : class1_set.iter ())
+    {
+      for (const unsigned class2_idx : class2_set.iter ())
+      {
+        unsigned start_offset = (class1_idx * (unsigned) class2Count + class2_idx) * (len1 + len2);
+        if (valueFormat1.has_device ())
+          valueFormat1.collect_variation_indices (c, this, values_array.sub_array (start_offset, len1));
+
+        if (valueFormat2.has_device ())
+          valueFormat2.collect_variation_indices (c, this, values_array.sub_array (start_offset+len1, len2));
+      }
+    }
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    if (unlikely (!(this+classDef2).collect_coverage (c->input))) return;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (index == NOT_COVERED)) return_trace (false);
+
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    unsigned unsafe_to;
+    if (!skippy_iter.next (&unsafe_to))
+    {
+      buffer->unsafe_to_concat (buffer->idx, unsafe_to);
+      return_trace (false);
+    }
+
+    unsigned int len1 = valueFormat1.get_len ();
+    unsigned int len2 = valueFormat2.get_len ();
+    unsigned int record_len = len1 + len2;
+
+    unsigned int klass1 = (this+classDef1).get_class (buffer->cur().codepoint);
+    unsigned int klass2 = (this+classDef2).get_class (buffer->info[skippy_iter.idx].codepoint);
+    if (unlikely (klass1 >= class1Count || klass2 >= class2Count))
+    {
+      buffer->unsafe_to_concat (buffer->idx, skippy_iter.idx + 1);
+      return_trace (false);
+    }
+
+    const Value *v = &values[record_len * (klass1 * class2Count + klass2)];
+
+    bool applied_first = false, applied_second = false;
+
+
+    /* Isolate simple kerning and apply it half to each side.
+     * Results in better cursor positinoing / underline drawing.
+     *
+     * Disabled, because causes issues... :-(
+     * https://github.com/harfbuzz/harfbuzz/issues/3408
+     * https://github.com/harfbuzz/harfbuzz/pull/3235#issuecomment-1029814978
+     */
+#ifndef HB_SPLIT_KERN
+    if (0)
+#endif
+    {
+      if (!len2)
+      {
+        const hb_direction_t dir = buffer->props.direction;
+        const bool horizontal = HB_DIRECTION_IS_HORIZONTAL (dir);
+        const bool backward = HB_DIRECTION_IS_BACKWARD (dir);
+        unsigned mask = horizontal ? ValueFormat::xAdvance : ValueFormat::yAdvance;
+        if (backward)
+          mask |= mask >> 2; /* Add eg. xPlacement in RTL. */
+        /* Add Devices. */
+        mask |= mask << 4;
+
+        if (valueFormat1 & ~mask)
+          goto bail;
+
+        /* Is simple kern. Apply value on an empty position slot,
+         * then split it between sides. */
+
+        hb_glyph_position_t pos{};
+        if (valueFormat1.apply_value (c, this, v, pos))
+        {
+          hb_position_t *src  = &pos.x_advance;
+          hb_position_t *dst1 = &buffer->cur_pos().x_advance;
+          hb_position_t *dst2 = &buffer->pos[skippy_iter.idx].x_advance;
+          unsigned i = horizontal ? 0 : 1;
+
+          hb_position_t kern  = src[i];
+          hb_position_t kern1 = kern >> 1;
+          hb_position_t kern2 = kern - kern1;
+
+          if (!backward)
+          {
+            dst1[i] += kern1;
+            dst2[i] += kern2;
+            dst2[i + 2] += kern2;
+          }
+          else
+          {
+            dst1[i] += kern1;
+            dst1[i + 2] += src[i + 2] - kern2;
+            dst2[i] += kern2;
+          }
+
+          applied_first = applied_second = kern != 0;
+          goto success;
+        }
+        goto boring;
+      }
+    }
+    bail:
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "try kerning glyphs at %d,%d",
+			  c->buffer->idx, skippy_iter.idx);
+    }
+
+    applied_first = valueFormat1.apply_value (c, this, v, buffer->cur_pos());
+    applied_second = valueFormat2.apply_value (c, this, v + len1, buffer->pos[skippy_iter.idx]);
+
+    if (applied_first || applied_second)
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->message (c->font,
+			    "kerned glyphs at %d,%d",
+			    c->buffer->idx, skippy_iter.idx);
+      }
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "tried kerning glyphs at %d,%d",
+			  c->buffer->idx, skippy_iter.idx);
+    }
+
+    success:
+    if (applied_first || applied_second)
+      buffer->unsafe_to_break (buffer->idx, skippy_iter.idx + 1);
+    else
+    boring:
+      buffer->unsafe_to_concat (buffer->idx, skippy_iter.idx + 1);
+
+    if (len2)
+    {
+      skippy_iter.idx++;
+      // https://github.com/harfbuzz/harfbuzz/issues/3824
+      // https://github.com/harfbuzz/harfbuzz/issues/3888#issuecomment-1326781116
+      buffer->unsafe_to_break (buffer->idx, skippy_iter.idx + 1);
+    }
+
+    buffer->idx = skippy_iter.idx;
+
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->format = format;
+
+    hb_map_t klass1_map;
+    out->classDef1.serialize_subset (c, classDef1, this, &klass1_map, true, true, &(this + coverage));
+    out->class1Count = klass1_map.get_population ();
+
+    hb_map_t klass2_map;
+    out->classDef2.serialize_subset (c, classDef2, this, &klass2_map, true, false);
+    out->class2Count = klass2_map.get_population ();
+
+    unsigned len1 = valueFormat1.get_len ();
+    unsigned len2 = valueFormat2.get_len ();
+
+    hb_pair_t<unsigned, unsigned> newFormats = hb_pair (valueFormat1, valueFormat2);
+    if (c->plan->flags & HB_SUBSET_FLAGS_NO_HINTING)
+      newFormats = compute_effective_value_formats (klass1_map, klass2_map);
+
+    out->valueFormat1 = newFormats.first;
+    out->valueFormat2 = newFormats.second;
+
+    if (c->plan->all_axes_pinned)
+    {
+      out->valueFormat1 = out->valueFormat1.drop_device_table_flags ();
+      out->valueFormat2 = out->valueFormat2.drop_device_table_flags ();
+    }
+
+    for (unsigned class1_idx : + hb_range ((unsigned) class1Count) | hb_filter (klass1_map))
+    {
+      for (unsigned class2_idx : + hb_range ((unsigned) class2Count) | hb_filter (klass2_map))
+      {
+        unsigned idx = (class1_idx * (unsigned) class2Count + class2_idx) * (len1 + len2);
+        valueFormat1.copy_values (c->serializer, out->valueFormat1, this, &values[idx], c->plan->layout_variation_idx_delta_map);
+        valueFormat2.copy_values (c->serializer, out->valueFormat2, this, &values[idx + len1], c->plan->layout_variation_idx_delta_map);
+      }
+    }
+
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto it =
+    + hb_iter (this+coverage)
+    | hb_filter (glyphset)
+    | hb_map_retains_sorting (glyph_map)
+    ;
+
+    out->coverage.serialize_serialize (c->serializer, it);
+    return_trace (out->class1Count && out->class2Count && bool (it));
+  }
+
+
+  hb_pair_t<unsigned, unsigned> compute_effective_value_formats (const hb_map_t& klass1_map,
+                                                                 const hb_map_t& klass2_map) const
+  {
+    unsigned len1 = valueFormat1.get_len ();
+    unsigned len2 = valueFormat2.get_len ();
+    unsigned record_size = len1 + len2;
+
+    unsigned format1 = 0;
+    unsigned format2 = 0;
+
+    for (unsigned class1_idx : + hb_range ((unsigned) class1Count) | hb_filter (klass1_map))
+    {
+      for (unsigned class2_idx : + hb_range ((unsigned) class2Count) | hb_filter (klass2_map))
+      {
+        unsigned idx = (class1_idx * (unsigned) class2Count + class2_idx) * record_size;
+        format1 = format1 | valueFormat1.get_effective_format (&values[idx]);
+        format2 = format2 | valueFormat2.get_effective_format (&values[idx + len1]);
+      }
+
+      if (format1 == valueFormat1 && format2 == valueFormat2)
+        break;
+    }
+
+    return hb_pair (format1, format2);
+  }
+};
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PairSet.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PairSet.hh
new file mode 100644
index 0000000000..a318f39913
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PairSet.hh
@@ -0,0 +1,203 @@
+#ifndef OT_LAYOUT_GPOS_PAIRSET_HH
+#define OT_LAYOUT_GPOS_PAIRSET_HH
+
+#include "PairValueRecord.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+
+template <typename Types>
+struct PairSet
+{
+  template <typename Types2>
+  friend struct PairPosFormat1_3;
+
+  using PairValueRecord = GPOS_impl::PairValueRecord<Types>;
+
+  protected:
+  HBUINT16              len;    /* Number of PairValueRecords */
+  PairValueRecord       firstPairValueRecord;
+                                /* Array of PairValueRecords--ordered
+                                 * by GlyphID of the second glyph */
+  public:
+  DEFINE_SIZE_MIN (2);
+
+  struct sanitize_closure_t
+  {
+    const ValueFormat *valueFormats;
+    unsigned int len1; /* valueFormats[0].get_len() */
+    unsigned int stride; /* 1 + len1 + len2 */
+  };
+
+  bool sanitize (hb_sanitize_context_t *c, const sanitize_closure_t *closure) const
+  {
+    TRACE_SANITIZE (this);
+    if (!(c->check_struct (this)
+       && c->check_range (&firstPairValueRecord,
+                          len,
+                          HBUINT16::static_size,
+                          closure->stride))) return_trace (false);
+
+    unsigned int count = len;
+    const PairValueRecord *record = &firstPairValueRecord;
+    return_trace (closure->valueFormats[0].sanitize_values_stride_unsafe (c, this, &record->values[0], count, closure->stride) &&
+                  closure->valueFormats[1].sanitize_values_stride_unsafe (c, this, &record->values[closure->len1], count, closure->stride));
+  }
+
+  bool intersects (const hb_set_t *glyphs,
+                   const ValueFormat *valueFormats) const
+  {
+    unsigned int len1 = valueFormats[0].get_len ();
+    unsigned int len2 = valueFormats[1].get_len ();
+    unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
+
+    const PairValueRecord *record = &firstPairValueRecord;
+    unsigned int count = len;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      if (glyphs->has (record->secondGlyph))
+        return true;
+      record = &StructAtOffset<const PairValueRecord> (record, record_size);
+    }
+    return false;
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c,
+                       const ValueFormat *valueFormats) const
+  {
+    unsigned int len1 = valueFormats[0].get_len ();
+    unsigned int len2 = valueFormats[1].get_len ();
+    unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
+
+    const PairValueRecord *record = &firstPairValueRecord;
+    c->input->add_array (&record->secondGlyph, len, record_size);
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const ValueFormat *valueFormats) const
+  {
+    unsigned len1 = valueFormats[0].get_len ();
+    unsigned len2 = valueFormats[1].get_len ();
+    unsigned record_size = HBUINT16::static_size * (1 + len1 + len2);
+
+    const PairValueRecord *record = &firstPairValueRecord;
+    unsigned count = len;
+    for (unsigned i = 0; i < count; i++)
+    {
+      if (c->glyph_set->has (record->secondGlyph))
+      { record->collect_variation_indices (c, valueFormats, this); }
+
+      record = &StructAtOffset<const PairValueRecord> (record, record_size);
+    }
+  }
+
+  bool apply (hb_ot_apply_context_t *c,
+              const ValueFormat *valueFormats,
+              unsigned int pos) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int len1 = valueFormats[0].get_len ();
+    unsigned int len2 = valueFormats[1].get_len ();
+    unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
+
+    const PairValueRecord *record = hb_bsearch (buffer->info[pos].codepoint,
+                                                &firstPairValueRecord,
+                                                len,
+                                                record_size);
+    if (record)
+    {
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->message (c->font,
+			    "try kerning glyphs at %d,%d",
+			    c->buffer->idx, pos);
+      }
+
+      bool applied_first = valueFormats[0].apply_value (c, this, &record->values[0], buffer->cur_pos());
+      bool applied_second = valueFormats[1].apply_value (c, this, &record->values[len1], buffer->pos[pos]);
+
+      if (applied_first || applied_second)
+	if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+	{
+	  c->buffer->message (c->font,
+			      "kerned glyphs at %d,%d",
+			      c->buffer->idx, pos);
+	}
+
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->message (c->font,
+			    "tried kerning glyphs at %d,%d",
+			    c->buffer->idx, pos);
+      }
+
+      if (applied_first || applied_second)
+        buffer->unsafe_to_break (buffer->idx, pos + 1);
+
+      if (len2)
+      {
+	pos++;
+      // https://github.com/harfbuzz/harfbuzz/issues/3824
+      // https://github.com/harfbuzz/harfbuzz/issues/3888#issuecomment-1326781116
+      buffer->unsafe_to_break (buffer->idx, pos + 1);
+      }
+
+      buffer->idx = pos;
+      return_trace (true);
+    }
+    buffer->unsafe_to_concat (buffer->idx, pos + 1);
+    return_trace (false);
+  }
+
+  bool subset (hb_subset_context_t *c,
+               const ValueFormat valueFormats[2],
+               const ValueFormat newFormats[2]) const
+  {
+    TRACE_SUBSET (this);
+    auto snap = c->serializer->snapshot ();
+
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->len = 0;
+
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    unsigned len1 = valueFormats[0].get_len ();
+    unsigned len2 = valueFormats[1].get_len ();
+    unsigned record_size = HBUINT16::static_size + Value::static_size * (len1 + len2);
+
+    typename PairValueRecord::context_t context =
+    {
+      this,
+      valueFormats,
+      newFormats,
+      len1,
+      &glyph_map,
+      c->plan->layout_variation_idx_delta_map
+    };
+
+    const PairValueRecord *record = &firstPairValueRecord;
+    unsigned count = len, num = 0;
+    for (unsigned i = 0; i < count; i++)
+    {
+      if (glyphset.has (record->secondGlyph)
+         && record->subset (c, &context)) num++;
+      record = &StructAtOffset<const PairValueRecord> (record, record_size);
+    }
+
+    out->len = num;
+    if (!num) c->serializer->revert (snap);
+    return_trace (num);
+  }
+};
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_PAIRSET_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PairValueRecord.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PairValueRecord.hh
new file mode 100644
index 0000000000..3222477764
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PairValueRecord.hh
@@ -0,0 +1,99 @@
+#ifndef OT_LAYOUT_GPOS_PAIRVALUERECORD_HH
+#define OT_LAYOUT_GPOS_PAIRVALUERECORD_HH
+
+#include "ValueFormat.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+
+template <typename Types>
+struct PairValueRecord
+{
+  template <typename Types2>
+  friend struct PairSet;
+
+  protected:
+  typename Types::HBGlyphID
+	        secondGlyph;            /* GlyphID of second glyph in the
+                                         * pair--first glyph is listed in the
+                                         * Coverage table */
+  ValueRecord   values;                 /* Positioning data for the first glyph
+                                         * followed by for second glyph */
+  public:
+  DEFINE_SIZE_ARRAY (Types::size, values);
+
+  int cmp (hb_codepoint_t k) const
+  { return secondGlyph.cmp (k); }
+
+  struct context_t
+  {
+    const void          *base;
+    const ValueFormat   *valueFormats;
+    const ValueFormat   *newFormats;
+    unsigned            len1; /* valueFormats[0].get_len() */
+    const hb_map_t      *glyph_map;
+    const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map;
+  };
+
+  bool subset (hb_subset_context_t *c,
+               context_t *closure) const
+  {
+    TRACE_SERIALIZE (this);
+    auto *s = c->serializer;
+    auto *out = s->start_embed (*this);
+    if (unlikely (!s->extend_min (out))) return_trace (false);
+
+    out->secondGlyph = (*closure->glyph_map)[secondGlyph];
+
+    closure->valueFormats[0].copy_values (s,
+                                          closure->newFormats[0],
+                                          closure->base, &values[0],
+                                          closure->layout_variation_idx_delta_map);
+    closure->valueFormats[1].copy_values (s,
+                                          closure->newFormats[1],
+                                          closure->base,
+                                          &values[closure->len1],
+                                          closure->layout_variation_idx_delta_map);
+
+    return_trace (true);
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const ValueFormat *valueFormats,
+                                  const void *base) const
+  {
+    unsigned record1_len = valueFormats[0].get_len ();
+    unsigned record2_len = valueFormats[1].get_len ();
+    const hb_array_t<const Value> values_array = values.as_array (record1_len + record2_len);
+
+    if (valueFormats[0].has_device ())
+      valueFormats[0].collect_variation_indices (c, base, values_array.sub_array (0, record1_len));
+
+    if (valueFormats[1].has_device ())
+      valueFormats[1].collect_variation_indices (c, base, values_array.sub_array (record1_len, record2_len));
+  }
+
+  bool intersects (const hb_set_t& glyphset) const
+  {
+    return glyphset.has(secondGlyph);
+  }
+
+  const Value* get_values_1 () const
+  {
+    return &values[0];
+  }
+
+  const Value* get_values_2 (ValueFormat format1) const
+  {
+    return &values[format1.get_len ()];
+  }
+};
+
+
+}
+}
+}
+
+#endif  // OT_LAYOUT_GPOS_PAIRVALUERECORD_HH
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookup.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookup.hh
new file mode 100644
index 0000000000..c4e57bb543
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookup.hh
@@ -0,0 +1,79 @@
+#ifndef OT_LAYOUT_GPOS_POSLOOKUP_HH
+#define OT_LAYOUT_GPOS_POSLOOKUP_HH
+
+#include "PosLookupSubTable.hh"
+#include "../../../hb-ot-layout-common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct PosLookup : Lookup
+{
+  using SubTable = PosLookupSubTable;
+
+  const SubTable& get_subtable (unsigned int i) const
+  { return Lookup::get_subtable<SubTable> (i); }
+
+  bool is_reverse () const
+  {
+    return false;
+  }
+
+  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_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { return dispatch (c); }
+
+  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 ();
+    }
+
+    hb_closure_lookups_context_t::return_t ret = dispatch (c);
+    return ret;
+  }
+
+  template <typename set_t>
+  void collect_coverage (set_t *glyphs) const
+  {
+    hb_collect_coverage_context_t<set_t> c (glyphs);
+    dispatch (&c);
+  }
+
+  template <typename context_t>
+  static typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int 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); }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  { return Lookup::sanitize<SubTable> (c); }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GPOS_POSLOOKUP_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookupSubTable.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookupSubTable.hh
new file mode 100644
index 0000000000..c19fbc323f
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/PosLookupSubTable.hh
@@ -0,0 +1,79 @@
+#ifndef OT_LAYOUT_GPOS_POSLOOKUPSUBTABLE_HH
+#define OT_LAYOUT_GPOS_POSLOOKUPSUBTABLE_HH
+
+#include "SinglePos.hh"
+#include "PairPos.hh"
+#include "CursivePos.hh"
+#include "MarkBasePos.hh"
+#include "MarkLigPos.hh"
+#include "MarkMarkPos.hh"
+#include "ContextPos.hh"
+#include "ChainContextPos.hh"
+#include "ExtensionPos.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct PosLookupSubTable
+{
+  friend struct ::OT::Lookup;
+  friend struct PosLookup;
+
+  enum Type {
+    Single              = 1,
+    Pair                = 2,
+    Cursive             = 3,
+    MarkBase            = 4,
+    MarkLig             = 5,
+    MarkMark            = 6,
+    Context             = 7,
+    ChainContext        = 8,
+    Extension           = 9
+  };
+
+  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 Pair:                  return_trace (u.pair.dispatch (c, std::forward<Ts> (ds)...));
+    case Cursive:               return_trace (u.cursive.dispatch (c, std::forward<Ts> (ds)...));
+    case MarkBase:              return_trace (u.markBase.dispatch (c, std::forward<Ts> (ds)...));
+    case MarkLig:               return_trace (u.markLig.dispatch (c, std::forward<Ts> (ds)...));
+    case MarkMark:              return_trace (u.markMark.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)...));
+    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);
+  }
+
+  protected:
+  union {
+  SinglePos             single;
+  PairPos               pair;
+  CursivePos            cursive;
+  MarkBasePos           markBase;
+  MarkLigPos            markLig;
+  MarkMarkPos           markMark;
+  ContextPos            context;
+  ChainContextPos       chainContext;
+  ExtensionPos          extension;
+  } u;
+  public:
+  DEFINE_SIZE_MIN (0);
+};
+
+}
+}
+}
+
+#endif  /* HB_OT_LAYOUT_GPOS_POSLOOKUPSUBTABLE_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePos.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePos.hh
new file mode 100644
index 0000000000..6dce3e6343
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePos.hh
@@ -0,0 +1,100 @@
+#ifndef OT_LAYOUT_GPOS_SINGLEPOS_HH
+#define OT_LAYOUT_GPOS_SINGLEPOS_HH
+
+#include "SinglePosFormat1.hh"
+#include "SinglePosFormat2.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct SinglePos
+{
+  protected:
+  union {
+  HBUINT16              format;         /* Format identifier */
+  SinglePosFormat1      format1;
+  SinglePosFormat2      format2;
+  } u;
+
+  public:
+  template<typename Iterator,
+           hb_requires (hb_is_iterator (Iterator))>
+  unsigned get_format (Iterator glyph_val_iter_pairs)
+  {
+    hb_array_t<const Value> first_val_iter = hb_second (*glyph_val_iter_pairs);
+
+    for (const auto iter : glyph_val_iter_pairs)
+      for (const auto _ : hb_zip (iter.second, first_val_iter))
+        if (_.first != _.second)
+          return 2;
+
+    return 1;
+  }
+
+  template<typename Iterator,
+      typename SrcLookup,
+      hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+                  const SrcLookup* src,
+                  Iterator glyph_val_iter_pairs,
+                  const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map,
+                  bool all_axes_pinned)
+  {
+    if (unlikely (!c->extend_min (u.format))) return;
+    unsigned format = 2;
+    ValueFormat new_format = src->get_value_format ();
+
+    if (all_axes_pinned)
+      new_format = new_format.drop_device_table_flags ();
+
+    if (glyph_val_iter_pairs)
+      format = get_format (glyph_val_iter_pairs);
+
+    u.format = format;
+    switch (u.format) {
+    case 1: u.format1.serialize (c,
+                                 src,
+                                 glyph_val_iter_pairs,
+                                 new_format,
+                                 layout_variation_idx_delta_map);
+      return;
+    case 2: u.format2.serialize (c,
+                                 src,
+                                 glyph_val_iter_pairs,
+                                 new_format,
+                                 layout_variation_idx_delta_map);
+      return;
+    default:return;
+    }
+  }
+
+  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, typename SrcLookup>
+static void
+SinglePos_serialize (hb_serialize_context_t *c,
+                     const SrcLookup *src,
+                     Iterator it,
+                     const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map,
+                     bool all_axes_pinned)
+{ c->start_embed<SinglePos> ()->serialize (c, src, it, layout_variation_idx_delta_map, all_axes_pinned); }
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_SINGLEPOS_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat1.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat1.hh
new file mode 100644
index 0000000000..b4c9fc3db0
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat1.hh
@@ -0,0 +1,156 @@
+#ifndef OT_LAYOUT_GPOS_SINGLEPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_SINGLEPOSFORMAT1_HH
+
+#include "Common.hh"
+#include "ValueFormat.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct SinglePosFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  ValueFormat   valueFormat;            /* Defines the types of data in the
+                                         * ValueRecord */
+  ValueRecord   values;                 /* Defines positioning
+                                         * value(s)--applied to all glyphs in
+                                         * the Coverage table */
+  public:
+  DEFINE_SIZE_ARRAY (6, values);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+                  coverage.sanitize (c, this) &&
+                  valueFormat.sanitize_value (c, this, values));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    if (!valueFormat.has_device ()) return;
+
+    hb_set_t intersection;
+    (this+coverage).intersect_set (*c->glyph_set, intersection);
+    if (!intersection) return;
+
+    valueFormat.collect_variation_indices (c, this, values.as_array (valueFormat.get_len ()));
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { if (unlikely (!(this+coverage).collect_coverage (c->input))) return; }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  ValueFormat get_value_format () const { return valueFormat; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (index == NOT_COVERED)) return_trace (false);
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "positioning glyph at %d",
+			  c->buffer->idx);
+    }
+
+    valueFormat.apply_value (c, this, values, buffer->cur_pos());
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "positioned glyph at %d",
+			  c->buffer->idx);
+    }
+
+    buffer->idx++;
+    return_trace (true);
+  }
+
+  bool
+  position_single (hb_font_t           *font,
+		   hb_direction_t       direction,
+		   hb_codepoint_t       gid,
+		   hb_glyph_position_t &pos) const
+  {
+    unsigned int index = (this+coverage).get_coverage  (gid);
+    if (likely (index == NOT_COVERED)) return false;
+
+    /* This is ugly... */
+    hb_buffer_t buffer;
+    buffer.props.direction = direction;
+    OT::hb_ot_apply_context_t c (1, font, &buffer);
+
+    valueFormat.apply_value (&c, this, values, pos);
+    return true;
+  }
+
+  template<typename Iterator,
+      typename SrcLookup,
+      hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+                  const SrcLookup *src,
+                  Iterator it,
+                  ValueFormat newFormat,
+                  const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map)
+  {
+    if (unlikely (!c->extend_min (this))) return;
+    if (unlikely (!c->check_assign (valueFormat,
+                                    newFormat,
+                                    HB_SERIALIZE_ERROR_INT_OVERFLOW))) return;
+
+    for (const hb_array_t<const Value>& _ : + it | hb_map (hb_second))
+    {
+      src->get_value_format ().copy_values (c, newFormat, src,  &_, layout_variation_idx_delta_map);
+      // Only serialize the first entry in the iterator, the rest are assumed to
+      // be the same.
+      break;
+    }
+
+    auto glyphs =
+    + it
+    | hb_map_retains_sorting (hb_first)
+    ;
+
+    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;
+
+    hb_set_t intersection;
+    (this+coverage).intersect_set (glyphset, intersection);
+
+    auto it =
+    + hb_iter (intersection)
+    | hb_map_retains_sorting (glyph_map)
+    | hb_zip (hb_repeat (values.as_array (valueFormat.get_len ())))
+    ;
+
+    bool ret = bool (it);
+    SinglePos_serialize (c->serializer, this, it, c->plan->layout_variation_idx_delta_map, c->plan->all_axes_pinned);
+    return_trace (ret);
+  }
+};
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_SINGLEPOSFORMAT1_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat2.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat2.hh
new file mode 100644
index 0000000000..c77951156b
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/SinglePosFormat2.hh
@@ -0,0 +1,176 @@
+#ifndef OT_LAYOUT_GPOS_SINGLEPOSFORMAT2_HH
+#define OT_LAYOUT_GPOS_SINGLEPOSFORMAT2_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct SinglePosFormat2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 2 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  ValueFormat   valueFormat;            /* Defines the types of data in the
+                                         * ValueRecord */
+  HBUINT16      valueCount;             /* Number of ValueRecords */
+  ValueRecord   values;                 /* Array of ValueRecords--positioning
+                                         * values applied to glyphs */
+  public:
+  DEFINE_SIZE_ARRAY (8, values);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+                  coverage.sanitize (c, this) &&
+                  valueFormat.sanitize_values (c, this, values, valueCount));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    if (!valueFormat.has_device ()) return;
+
+    auto it =
+    + hb_zip (this+coverage, hb_range ((unsigned) valueCount))
+    | hb_filter (c->glyph_set, hb_first)
+    ;
+
+    if (!it) return;
+
+    unsigned sub_length = valueFormat.get_len ();
+    const hb_array_t<const Value> values_array = values.as_array (valueCount * sub_length);
+
+    for (unsigned i : + it
+                      | hb_map (hb_second))
+      valueFormat.collect_variation_indices (c, this, values_array.sub_array (i * sub_length, sub_length));
+
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { if (unlikely (!(this+coverage).collect_coverage (c->input))) return; }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  ValueFormat get_value_format () const { return valueFormat; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+    unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
+    if (likely (index == NOT_COVERED)) return_trace (false);
+
+    if (unlikely (index >= valueCount)) return_trace (false);
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "positioning glyph at %d",
+			  c->buffer->idx);
+    }
+
+    valueFormat.apply_value (c, this,
+                             &values[index * valueFormat.get_len ()],
+                             buffer->cur_pos());
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->message (c->font,
+			  "positioned glyph at %d",
+			  c->buffer->idx);
+    }
+
+    buffer->idx++;
+    return_trace (true);
+  }
+
+  bool
+  position_single (hb_font_t           *font,
+		   hb_direction_t       direction,
+		   hb_codepoint_t       gid,
+		   hb_glyph_position_t &pos) const
+  {
+    unsigned int index = (this+coverage).get_coverage  (gid);
+    if (likely (index == NOT_COVERED)) return false;
+    if (unlikely (index >= valueCount)) return false;
+
+    /* This is ugly... */
+    hb_buffer_t buffer;
+    buffer.props.direction = direction;
+    OT::hb_ot_apply_context_t c (1, font, &buffer);
+
+    valueFormat.apply_value (&c, this,
+                             &values[index * valueFormat.get_len ()],
+                             pos);
+    return true;
+  }
+
+
+  template<typename Iterator,
+      typename SrcLookup,
+      hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+                  const SrcLookup *src,
+                  Iterator it,
+                  ValueFormat newFormat,
+                  const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map)
+  {
+    auto out = c->extend_min (this);
+    if (unlikely (!out)) return;
+    if (unlikely (!c->check_assign (valueFormat, newFormat, HB_SERIALIZE_ERROR_INT_OVERFLOW))) return;
+    if (unlikely (!c->check_assign (valueCount, it.len (), HB_SERIALIZE_ERROR_ARRAY_OVERFLOW))) return;
+
+    + it
+    | hb_map (hb_second)
+    | hb_apply ([&] (hb_array_t<const Value> _)
+    { src->get_value_format ().copy_values (c, newFormat, src, &_, layout_variation_idx_delta_map); })
+    ;
+
+    auto glyphs =
+    + it
+    | hb_map_retains_sorting (hb_first)
+    ;
+
+    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;
+
+    unsigned sub_length = valueFormat.get_len ();
+    auto values_array = values.as_array (valueCount * sub_length);
+
+    auto it =
+    + hb_zip (this+coverage, hb_range ((unsigned) valueCount))
+    | hb_filter (glyphset, hb_first)
+    | hb_map_retains_sorting ([&] (const hb_pair_t<hb_codepoint_t, unsigned>& _)
+                              {
+                                return hb_pair (glyph_map[_.first],
+                                                values_array.sub_array (_.second * sub_length,
+                                                                        sub_length));
+                              })
+    ;
+
+    bool ret = bool (it);
+    SinglePos_serialize (c->serializer, this, it, c->plan->layout_variation_idx_delta_map, c->plan->all_axes_pinned);
+    return_trace (ret);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_SINGLEPOSFORMAT2_HH */
diff --git a/gfx/harfbuzz/src/OT/Layout/GPOS/ValueFormat.hh b/gfx/harfbuzz/src/OT/Layout/GPOS/ValueFormat.hh
new file mode 100644
index 0000000000..26a40f01a3
--- /dev/null
+++ b/gfx/harfbuzz/src/OT/Layout/GPOS/ValueFormat.hh
@@ -0,0 +1,394 @@
+#ifndef OT_LAYOUT_GPOS_VALUEFORMAT_HH
+#define OT_LAYOUT_GPOS_VALUEFORMAT_HH
+
+#include "../../../hb-ot-layout-gsubgpos.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+typedef HBUINT16 Value;
+
+typedef UnsizedArrayOf<Value> ValueRecord;
+
+struct ValueFormat : HBUINT16
+{
+  enum Flags {
+    xPlacement  = 0x0001u,      /* Includes horizontal adjustment for placement */
+    yPlacement  = 0x0002u,      /* Includes vertical adjustment for placement */
+    xAdvance    = 0x0004u,      /* Includes horizontal adjustment for advance */
+    yAdvance    = 0x0008u,      /* Includes vertical adjustment for advance */
+    xPlaDevice  = 0x0010u,      /* Includes horizontal Device table for placement */
+    yPlaDevice  = 0x0020u,      /* Includes vertical Device table for placement */
+    xAdvDevice  = 0x0040u,      /* Includes horizontal Device table for advance */
+    yAdvDevice  = 0x0080u,      /* Includes vertical Device table for advance */
+    ignored     = 0x0F00u,      /* Was used in TrueType Open for MM fonts */
+    reserved    = 0xF000u,      /* For future use */
+
+    devices     = 0x00F0u       /* Mask for having any Device table */
+  };
+
+/* All fields are options.  Only those available advance the value pointer. */
+#if 0
+  HBINT16               xPlacement;     /* Horizontal adjustment for
+                                         * placement--in design units */
+  HBINT16               yPlacement;     /* Vertical adjustment for
+                                         * placement--in design units */
+  HBINT16               xAdvance;       /* Horizontal adjustment for
+                                         * advance--in design units (only used
+                                         * for horizontal writing) */
+  HBINT16               yAdvance;       /* Vertical adjustment for advance--in
+                                         * design units (only used for vertical
+                                         * writing) */
+  Offset16To<Device>    xPlaDevice;     /* Offset to Device table for
+                                         * horizontal placement--measured from
+                                         * beginning of PosTable (may be NULL) */
+  Offset16To<Device>    yPlaDevice;     /* Offset to Device table for vertical
+                                         * placement--measured from beginning
+                                         * of PosTable (may be NULL) */
+  Offset16To<Device>    xAdvDevice;     /* Offset to Device table for
+                                         * horizontal advance--measured from
+                                         * beginning of PosTable (may be NULL) */
+  Offset16To<Device>    yAdvDevice;     /* Offset to Device table for vertical
+                                         * advance--measured from beginning of
+                                         * PosTable (may be NULL) */
+#endif
+
+  IntType& operator = (uint16_t i) { v = i; return *this; }
+
+  unsigned int get_len () const  { return hb_popcount ((unsigned int) *this); }
+  unsigned int get_size () const { return get_len () * Value::static_size; }
+
+  hb_vector_t<unsigned> get_device_table_indices () const {
+    unsigned i = 0;
+    hb_vector_t<unsigned> result;
+    unsigned format = *this;
+
+    if (format & xPlacement) i++;
+    if (format & yPlacement) i++;
+    if (format & xAdvance)   i++;
+    if (format & yAdvance)   i++;
+
+    if (format & xPlaDevice) result.push (i++);
+    if (format & yPlaDevice) result.push (i++);
+    if (format & xAdvDevice) result.push (i++);
+    if (format & yAdvDevice) result.push (i++);
+
+    return result;
+  }
+
+  bool apply_value (hb_ot_apply_context_t *c,
+                    const void            *base,
+                    const Value           *values,
+                    hb_glyph_position_t   &glyph_pos) const
+  {
+    bool ret = false;
+    unsigned int format = *this;
+    if (!format) return ret;
+
+    hb_font_t *font = c->font;
+    bool horizontal =
+#ifndef HB_NO_VERTICAL
+      HB_DIRECTION_IS_HORIZONTAL (c->direction)
+#else
+      true
+#endif
+      ;
+
+    if (format & xPlacement) glyph_pos.x_offset  += font->em_scale_x (get_short (values++, &ret));
+    if (format & yPlacement) glyph_pos.y_offset  += font->em_scale_y (get_short (values++, &ret));
+    if (format & xAdvance) {
+      if (likely (horizontal)) glyph_pos.x_advance += font->em_scale_x (get_short (values, &ret));
+      values++;
+    }
+    /* y_advance values grow downward but font-space grows upward, hence negation */
+    if (format & yAdvance) {
+      if (unlikely (!horizontal)) glyph_pos.y_advance -= font->em_scale_y (get_short (values, &ret));
+      values++;
+    }
+
+    if (!has_device ()) return ret;
+
+    bool use_x_device = font->x_ppem || font->num_coords;
+    bool use_y_device = font->y_ppem || font->num_coords;
+
+    if (!use_x_device && !use_y_device) return ret;
+
+    const VariationStore &store = c->var_store;
+    auto *cache = c->var_store_cache;
+
+    /* pixel -> fractional pixel */
+    if (format & xPlaDevice) {
+      if (use_x_device) glyph_pos.x_offset  += (base + get_device (values, &ret)).get_x_delta (font, store, cache);
+      values++;
+    }
+    if (format & yPlaDevice) {
+      if (use_y_device) glyph_pos.y_offset  += (base + get_device (values, &ret)).get_y_delta (font, store, cache);
+      values++;
+    }
+    if (format & xAdvDevice) {
+      if (horizontal && use_x_device) glyph_pos.x_advance += (base + get_device (values, &ret)).get_x_delta (font, store, cache);
+      values++;
+    }
+    if (format & yAdvDevice) {
+      /* y_advance values grow downward but font-space grows upward, hence negation */
+      if (!horizontal && use_y_device) glyph_pos.y_advance -= (base + get_device (values, &ret)).get_y_delta (font, store, cache);
+      values++;
+    }
+    return ret;
+  }
+
+  unsigned int get_effective_format (const Value *values) const
+  {
+    unsigned int format = *this;
+    for (unsigned flag = xPlacement; flag <= yAdvDevice; flag = flag << 1) {
+      if (format & flag) should_drop (*values++, (Flags) flag, &format);
+    }
+
+    return format;
+  }
+
+  template<typename Iterator,
+      hb_requires (hb_is_iterator (Iterator))>
+  unsigned int get_effective_format (Iterator it) const {
+    unsigned int new_format = 0;
+
+    for (const hb_array_t<const Value>& values : it)
+      new_format = new_format | get_effective_format (&values);
+
+    return new_format;
+  }
+
+  void copy_values (hb_serialize_context_t *c,
+                    unsigned int new_format,
+                    const void *base,
+                    const Value *values,
+                    const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map) const
+  {
+    unsigned int format = *this;
+    if (!format) return;
+
+    HBINT16 *x_placement = nullptr, *y_placement = nullptr, *x_adv = nullptr, *y_adv = nullptr;
+    if (format & xPlacement) x_placement = copy_value (c, new_format, xPlacement, *values++);
+    if (format & yPlacement) y_placement = copy_value (c, new_format, yPlacement, *values++);
+    if (format & xAdvance)   x_adv = copy_value (c, new_format, xAdvance, *values++);
+    if (format & yAdvance)   y_adv = copy_value (c, new_format, yAdvance, *values++);
+
+    if (format & xPlaDevice)
+    {
+      add_delta_to_value (x_placement, base, values, layout_variation_idx_delta_map);
+      copy_device (c, base, values++, layout_variation_idx_delta_map, new_format, xPlaDevice);
+    }
+
+    if (format & yPlaDevice)
+    {
+      add_delta_to_value (y_placement, base, values, layout_variation_idx_delta_map);
+      copy_device (c, base, values++, layout_variation_idx_delta_map, new_format, yPlaDevice);
+    }
+
+    if (format & xAdvDevice)
+    {
+      add_delta_to_value (x_adv, base, values, layout_variation_idx_delta_map);
+      copy_device (c, base, values++, layout_variation_idx_delta_map, new_format, xAdvDevice);
+    }
+
+    if (format & yAdvDevice)
+    {
+      add_delta_to_value (y_adv, base, values, layout_variation_idx_delta_map);
+      copy_device (c, base, values++, layout_variation_idx_delta_map, new_format, yAdvDevice);
+    }
+  }
+
+  HBINT16* copy_value (hb_serialize_context_t *c,
+                       unsigned int new_format,
+                       Flags flag,
+                       Value value) const
+  {
+    // Filter by new format.
+    if (!(new_format & flag)) return nullptr;
+    return reinterpret_cast<HBINT16 *> (c->copy (value));
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const void *base,
+                                  const hb_array_t<const Value>& values) const
+  {
+    unsigned format = *this;
+    unsigned i = 0;
+    if (format & xPlacement) i++;
+    if (format & yPlacement) i++;
+    if (format & xAdvance) i++;
+    if (format & yAdvance) i++;
+    if (format & xPlaDevice)
+    {
+      (base + get_device (&(values[i]))).collect_variation_indices (c);
+      i++;
+    }
+
+    if (format & ValueFormat::yPlaDevice)
+    {
+      (base + get_device (&(values[i]))).collect_variation_indices (c);
+      i++;
+    }
+
+    if (format & ValueFormat::xAdvDevice)
+    {
+
+      (base + get_device (&(values[i]))).collect_variation_indices (c);
+      i++;
+    }
+
+    if (format & ValueFormat::yAdvDevice)
+    {
+
+      (base + get_device (&(values[i]))).collect_variation_indices (c);
+      i++;
+    }
+  }
+
+  unsigned drop_device_table_flags () const
+  {
+    unsigned format = *this;
+    for (unsigned flag = xPlaDevice; flag <= yAdvDevice; flag = flag << 1)
+      format = format & ~flag;
+
+    return format;
+  }
+
+  private:
+  bool sanitize_value_devices (hb_sanitize_context_t *c, const void *base, const Value *values) const
+  {
+    unsigned int format = *this;
+
+    if (format & xPlacement) values++;
+    if (format & yPlacement) values++;
+    if (format & xAdvance)   values++;
+    if (format & yAdvance)   values++;
+
+    if ((format & xPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
+    if ((format & yPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
+    if ((format & xAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
+    if ((format & yAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
+
+    return true;
+  }
+
+  static inline Offset16To<Device>& get_device (Value* value)
+  {
+    return *static_cast<Offset16To<Device> *> (value);
+  }
+  static inline const Offset16To<Device>& get_device (const Value* value, bool *worked=nullptr)
+  {
+    if (worked) *worked |= bool (*value);
+    return *static_cast<const Offset16To<Device> *> (value);
+  }
+
+  void add_delta_to_value (HBINT16 *value,
+                           const void *base,
+                           const Value *src_value,
+                           const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map) const
+  {
+    if (!value) return;
+    unsigned varidx = (base + get_device (src_value)).get_variation_index ();
+    hb_pair_t<unsigned, int> *varidx_delta;
+    if (!layout_variation_idx_delta_map->has (varidx, &varidx_delta)) return;
+
+    *value += hb_second (*varidx_delta);
+  }
+
+  bool copy_device (hb_serialize_context_t *c, const void *base,
+                    const Value *src_value,
+                    const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *layout_variation_idx_delta_map,
+                    unsigned int new_format, Flags flag) const
+  {
+    // Filter by new format.
+    if (!(new_format & flag)) return true;
+
+    Value       *dst_value = c->copy (*src_value);
+
+    if (!dst_value) return false;
+    if (*dst_value == 0) return true;
+
+    *dst_value = 0;
+    c->push ();
+    if ((base + get_device (src_value)).copy (c, layout_variation_idx_delta_map))
+    {
+      c->add_link (*dst_value, c->pop_pack ());
+      return true;
+    }
+    else
+    {
+      c->pop_discard ();
+      return false;
+    }
+  }
+
+  static inline const HBINT16& get_short (const Value* value, bool *worked=nullptr)
+  {
+    if (worked) *worked |= bool (*value);
+    return *reinterpret_cast<const HBINT16 *> (value);
+  }
+
+  public:
+
+  bool has_device () const
+  {
+    unsigned int format = *this;
+    return (format & devices) != 0;
+  }
+
+  bool sanitize_value (hb_sanitize_context_t *c, const void *base, const Value *values) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_range (values, get_size ()) && (!has_device () || sanitize_value_devices (c, base, values)));
+  }
+
+  bool sanitize_values (hb_sanitize_context_t *c, const void *base, const Value *values, unsigned int count) const
+  {
+    TRACE_SANITIZE (this);
+    unsigned int len = get_len ();
+
+    if (!c->check_range (values, count, get_size ())) return_trace (false);
+
+    if (!has_device ()) return_trace (true);
+
+    for (unsigned int i = 0; i < count; i++) {
+      if (!sanitize_value_devices (c, base, values))
+        return_trace (false);
+      values += len;
+    }
+
+    return_trace (true);
+  }
+
+  /* Just sanitize referenced Device tables.  Doesn't check the values themselves. */
+  bool sanitize_values_stride_unsafe (hb_sanitize_context_t *c, const void *base, const Value *values, unsigned int count, unsigned int stride) const
+  {
+    TRACE_SANITIZE (this);
+
+    if (!has_device ()) return_trace (true);
+
+    for (unsigned int i = 0; i < count; i++) {
+      if (!sanitize_value_devices (c, base, values))
+        return_trace (false);
+      values += stride;
+    }
+
+    return_trace (true);
+  }
+
+ private:
+
+  void should_drop (Value value, Flags flag, unsigned int* format) const
+  {
+    if (value) return;
+    *format = *format & ~flag;
+  }
+
+};
+
+}
+}
+}
+
+#endif  // #ifndef OT_LAYOUT_GPOS_VALUEFORMAT_HH