Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 878 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-ot-var-gvar-table.hh b/gfx/harfbuzz/src/hb-ot-var-gvar-table.hh
new file mode 100644
index 0000000000..1c7a1f6c1e
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-ot-var-gvar-table.hh
@@ -0,0 +1,878 @@
+/*
+ * Copyright © 2019  Adobe Inc.
+ * Copyright © 2019  Ebrahim Byagowi
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Adobe Author(s): Michiharu Ariza
+ */
+
+#ifndef HB_OT_VAR_GVAR_TABLE_HH
+#define HB_OT_VAR_GVAR_TABLE_HH
+
+#include "hb-open-type.hh"
+#include "hb-ot-var-common.hh"
+
+/*
+ * gvar -- Glyph Variation Table
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/gvar
+ */
+#define HB_OT_TAG_gvar HB_TAG('g','v','a','r')
+
+namespace OT {
+
+struct GlyphVariationData : TupleVariationData
+{};
+
+struct glyph_variations_t
+{
+  using tuple_variations_t = TupleVariationData::tuple_variations_t;
+  hb_vector_t<tuple_variations_t> glyph_variations;
+
+  hb_vector_t<char> compiled_shared_tuples;
+  private:
+  unsigned shared_tuples_count = 0;
+
+  /* shared coords-> index map after instantiation */
+  hb_hashmap_t<const hb_vector_t<char>*, unsigned> shared_tuples_idx_map;
+
+  public:
+  unsigned compiled_shared_tuples_count () const
+  { return shared_tuples_count; }
+
+  unsigned compiled_byte_size () const
+  {
+    unsigned byte_size = 0;
+    for (const auto& _ : glyph_variations)
+      byte_size += _.get_compiled_byte_size ();
+
+    return byte_size;
+  }
+
+  bool create_from_glyphs_var_data (unsigned axis_count,
+                                    const hb_array_t<const F2DOT14> shared_tuples,
+                                    const hb_subset_plan_t *plan,
+                                    const hb_hashmap_t<hb_codepoint_t, hb_bytes_t>& new_gid_var_data_map)
+  {
+    if (unlikely (!glyph_variations.alloc (plan->new_to_old_gid_list.length, true)))
+      return false;
+
+    auto it = hb_iter (plan->new_to_old_gid_list);
+    for (auto &_ : it)
+    {
+      hb_codepoint_t new_gid = _.first;
+      contour_point_vector_t *all_contour_points;
+      if (!new_gid_var_data_map.has (new_gid) ||
+          !plan->new_gid_contour_points_map.has (new_gid, &all_contour_points))
+        return false;
+      hb_bytes_t var_data = new_gid_var_data_map.get (new_gid);
+
+      const GlyphVariationData* p = reinterpret_cast<const GlyphVariationData*> (var_data.arrayZ);
+      hb_vector_t<unsigned> shared_indices;
+      GlyphVariationData::tuple_iterator_t iterator;
+      tuple_variations_t tuple_vars;
+
+      /* in case variation data is empty, push an empty struct into the vector,
+       * keep the vector in sync with the new_to_old_gid_list */
+      if (!var_data || ! p->has_data () || !all_contour_points->length ||
+          !GlyphVariationData::get_tuple_iterator (var_data, axis_count,
+                                                   var_data.arrayZ,
+                                                   shared_indices, &iterator))
+      {
+        glyph_variations.push (std::move (tuple_vars));
+        continue;
+      }
+
+      if (!p->decompile_tuple_variations (all_contour_points->length, true /* is_gvar */,
+                                          iterator, &(plan->axes_old_index_tag_map),
+                                          shared_indices, shared_tuples,
+                                          tuple_vars /* OUT */))
+        return false;
+      glyph_variations.push (std::move (tuple_vars));
+    }
+    return !glyph_variations.in_error () && glyph_variations.length == plan->new_to_old_gid_list.length;
+  }
+
+  bool instantiate (const hb_subset_plan_t *plan)
+  {
+    unsigned count = plan->new_to_old_gid_list.length;
+    for (unsigned i = 0; i < count; i++)
+    {
+      hb_codepoint_t new_gid = plan->new_to_old_gid_list[i].first;
+      contour_point_vector_t *all_points;
+      if (!plan->new_gid_contour_points_map.has (new_gid, &all_points))
+        return false;
+      if (!glyph_variations[i].instantiate (plan->axes_location, plan->axes_triple_distances, all_points))
+        return false;
+    }
+    return true;
+  }
+
+  bool compile_bytes (const hb_map_t& axes_index_map,
+                      const hb_map_t& axes_old_index_tag_map)
+  {
+    if (!compile_shared_tuples (axes_index_map, axes_old_index_tag_map))
+      return false;
+    for (tuple_variations_t& vars: glyph_variations)
+      if (!vars.compile_bytes (axes_index_map, axes_old_index_tag_map,
+                               true, /* use shared points*/
+                               &shared_tuples_idx_map))
+        return false;
+
+    return true;
+  }
+
+  bool compile_shared_tuples (const hb_map_t& axes_index_map,
+                              const hb_map_t& axes_old_index_tag_map)
+  {
+    /* key is pointer to compiled_peak_coords inside each tuple, hashing
+     * function will always deref pointers first */
+    hb_hashmap_t<const hb_vector_t<char>*, unsigned> coords_count_map;
+
+    /* count the num of shared coords */
+    for (tuple_variations_t& vars: glyph_variations)
+    {
+      for (tuple_delta_t& var : vars.tuple_vars)
+      {
+        if (!var.compile_peak_coords (axes_index_map, axes_old_index_tag_map))
+          return false;
+        unsigned* count;
+        if (coords_count_map.has (&(var.compiled_peak_coords), &count))
+          coords_count_map.set (&(var.compiled_peak_coords), *count + 1);
+        else
+          coords_count_map.set (&(var.compiled_peak_coords), 1);
+      }
+    }
+
+    if (!coords_count_map || coords_count_map.in_error ())
+      return false;
+
+    /* add only those coords that are used more than once into the vector and sort */
+    hb_vector_t<const hb_vector_t<char>*> shared_coords;
+    if (unlikely (!shared_coords.alloc (coords_count_map.get_population ())))
+      return false;
+
+    for (const auto _ : coords_count_map.iter ())
+    {
+      if (_.second == 1) continue;
+      shared_coords.push (_.first);
+    }
+
+    /* no shared tuples: no coords are used more than once */
+    if (!shared_coords) return true;
+    /* sorting based on the coords frequency first (high to low), then compare
+     * the coords bytes */
+    hb_qsort (shared_coords.arrayZ, shared_coords.length, sizeof (hb_vector_t<char>*), _cmp_coords, (void *) (&coords_count_map));
+
+    /* build shared_coords->idx map and shared tuples byte array */
+
+    shared_tuples_count = hb_min (0xFFFu + 1, shared_coords.length);
+    unsigned len = shared_tuples_count * (shared_coords[0]->length);
+    if (unlikely (!compiled_shared_tuples.alloc (len)))
+      return false;
+
+    for (unsigned i = 0; i < shared_tuples_count; i++)
+    {
+      shared_tuples_idx_map.set (shared_coords[i], i);
+      /* add a concat() in hb_vector_t? */
+      for (char c : shared_coords[i]->iter ())
+        compiled_shared_tuples.push (c);
+    }
+
+    return true;
+  }
+
+  static int _cmp_coords (const void *pa, const void *pb, void *arg)
+  {
+    const hb_hashmap_t<const hb_vector_t<char>*, unsigned>* coords_count_map =
+        reinterpret_cast<const hb_hashmap_t<const hb_vector_t<char>*, unsigned>*> (arg);
+
+    /* shared_coords is hb_vector_t<const hb_vector_t<char>*> so casting pa/pb
+     * to be a pointer to a pointer */
+    const hb_vector_t<char>** a = reinterpret_cast<const hb_vector_t<char>**> (const_cast<void*>(pa));
+    const hb_vector_t<char>** b = reinterpret_cast<const hb_vector_t<char>**> (const_cast<void*>(pb));
+
+    bool has_a = coords_count_map->has (*a);
+    bool has_b = coords_count_map->has (*b);
+
+    if (has_a && has_b)
+    {
+      unsigned a_num = coords_count_map->get (*a);
+      unsigned b_num = coords_count_map->get (*b);
+
+      if (a_num != b_num)
+        return b_num - a_num;
+
+      return (*b)->as_array().cmp ((*a)->as_array ());
+    }
+    else if (has_a) return -1;
+    else if (has_b) return 1;
+    else return 0;
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_iterator (Iterator))>
+  bool serialize_glyph_var_data (hb_serialize_context_t *c,
+                                 Iterator it,
+                                 bool long_offset,
+                                 unsigned num_glyphs,
+                                 char* glyph_var_data_offsets /* OUT: glyph var data offsets array */) const
+  {
+    TRACE_SERIALIZE (this);
+
+    if (long_offset)
+    {
+      ((HBUINT32 *) glyph_var_data_offsets)[0] = 0;
+      glyph_var_data_offsets += 4;
+    }
+    else
+    {
+      ((HBUINT16 *) glyph_var_data_offsets)[0] = 0;
+      glyph_var_data_offsets += 2;
+    }
+    unsigned glyph_offset = 0;
+    hb_codepoint_t last_gid = 0;
+    unsigned idx = 0;
+
+    TupleVariationData* cur_glyph = c->start_embed<TupleVariationData> ();
+    if (!cur_glyph) return_trace (false);
+    for (auto &_ : it)
+    {
+      hb_codepoint_t gid = _.first;
+      if (long_offset)
+        for (; last_gid < gid; last_gid++)
+          ((HBUINT32 *) glyph_var_data_offsets)[last_gid] = glyph_offset;
+      else
+        for (; last_gid < gid; last_gid++)
+          ((HBUINT16 *) glyph_var_data_offsets)[last_gid] = glyph_offset / 2;
+
+      if (idx >= glyph_variations.length) return_trace (false);
+      if (!cur_glyph->serialize (c, true, glyph_variations[idx])) return_trace (false);
+      TupleVariationData* next_glyph = c->start_embed<TupleVariationData> ();
+      glyph_offset += (char *) next_glyph - (char *) cur_glyph;
+
+      if (long_offset)
+        ((HBUINT32 *) glyph_var_data_offsets)[gid] = glyph_offset;
+      else
+        ((HBUINT16 *) glyph_var_data_offsets)[gid] = glyph_offset / 2;
+
+      last_gid++;
+      idx++;
+      cur_glyph = next_glyph;
+    }
+
+    if (long_offset)
+      for (; last_gid < num_glyphs; last_gid++)
+        ((HBUINT32 *) glyph_var_data_offsets)[last_gid] = glyph_offset;
+    else
+      for (; last_gid < num_glyphs; last_gid++)
+        ((HBUINT16 *) glyph_var_data_offsets)[last_gid] = glyph_offset / 2;
+    return_trace (true);
+  }
+};
+
+struct gvar
+{
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_gvar;
+
+  bool sanitize_shallow (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  hb_barrier () &&
+		  (version.major == 1) &&
+		  sharedTuples.sanitize (c, this, axisCount * sharedTupleCount) &&
+		  (is_long_offset () ?
+		     c->check_array (get_long_offset_array (), c->get_num_glyphs () + 1) :
+		     c->check_array (get_short_offset_array (), c->get_num_glyphs () + 1)));
+  }
+
+  /* GlyphVariationData not sanitized here; must be checked while accessing each glyph variation data */
+  bool sanitize (hb_sanitize_context_t *c) const
+  { return sanitize_shallow (c); }
+
+  bool decompile_glyph_variations (hb_subset_context_t *c,
+                                   glyph_variations_t& glyph_vars /* OUT */) const
+  {
+    hb_hashmap_t<hb_codepoint_t, hb_bytes_t> new_gid_var_data_map;
+    auto it = hb_iter (c->plan->new_to_old_gid_list);
+    if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
+    {
+      new_gid_var_data_map.set (0, hb_bytes_t ());
+      it++;
+    }
+
+    for (auto &_ : it)
+    {
+      hb_codepoint_t new_gid = _.first;
+      hb_codepoint_t old_gid = _.second;
+      hb_bytes_t var_data_bytes = get_glyph_var_data_bytes (c->source_blob, glyphCountX, old_gid);
+      new_gid_var_data_map.set (new_gid, var_data_bytes);
+    }
+
+    if (new_gid_var_data_map.in_error ()) return false;
+
+    hb_array_t<const F2DOT14> shared_tuples = (this+sharedTuples).as_array ((unsigned) sharedTupleCount * (unsigned) axisCount);
+    return glyph_vars.create_from_glyphs_var_data (axisCount, shared_tuples, c->plan, new_gid_var_data_map);
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_iterator (Iterator))>
+  bool serialize (hb_serialize_context_t *c,
+                  const glyph_variations_t& glyph_vars,
+                  Iterator it,
+                  unsigned axis_count,
+                  unsigned num_glyphs) const
+  {
+    TRACE_SERIALIZE (this);
+    gvar *out = c->allocate_min<gvar> ();
+    if (unlikely (!out)) return_trace (false);
+
+    out->version.major = 1;
+    out->version.minor = 0;
+    out->axisCount = axis_count;
+    out->glyphCountX = hb_min (0xFFFFu, num_glyphs);
+
+    unsigned glyph_var_data_size = glyph_vars.compiled_byte_size ();
+    bool long_offset = glyph_var_data_size & ~0xFFFFu;
+    out->flags = long_offset ? 1 : 0;
+
+    HBUINT8 *glyph_var_data_offsets = c->allocate_size<HBUINT8> ((long_offset ? 4 : 2) * (num_glyphs + 1), false);
+    if (!glyph_var_data_offsets) return_trace (false);
+
+    /* shared tuples */
+    unsigned shared_tuple_count = glyph_vars.compiled_shared_tuples_count ();
+    out->sharedTupleCount = shared_tuple_count;
+
+    if (!shared_tuple_count)
+      out->sharedTuples = 0;
+    else
+    {
+      hb_array_t<const char> shared_tuples = glyph_vars.compiled_shared_tuples.as_array ().copy (c);
+      if (!shared_tuples.arrayZ) return_trace (false);
+      out->sharedTuples = shared_tuples.arrayZ - (char *) out;
+    }
+
+    char *glyph_var_data = c->start_embed<char> ();
+    if (!glyph_var_data) return_trace (false);
+    out->dataZ = glyph_var_data - (char *) out;
+
+    return_trace (glyph_vars.serialize_glyph_var_data (c, it, long_offset, num_glyphs,
+                                                       (char *) glyph_var_data_offsets));
+  }
+
+  bool instantiate (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    glyph_variations_t glyph_vars;
+    if (!decompile_glyph_variations (c, glyph_vars))
+      return_trace (false);
+
+    if (!glyph_vars.instantiate (c->plan)) return_trace (false);
+    if (!glyph_vars.compile_bytes (c->plan->axes_index_map, c->plan->axes_old_index_tag_map))
+      return_trace (false);
+
+    unsigned axis_count = c->plan->axes_index_map.get_population ();
+    unsigned num_glyphs = c->plan->num_output_glyphs ();
+    auto it = hb_iter (c->plan->new_to_old_gid_list);
+    return_trace (serialize (c->serializer, glyph_vars, it, axis_count, num_glyphs));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    if (c->plan->all_axes_pinned)
+      return_trace (false);
+
+    if (c->plan->normalized_coords)
+      return_trace (instantiate (c));
+
+    unsigned glyph_count = version.to_int () ? c->plan->source->get_num_glyphs () : 0;
+
+    gvar *out = c->serializer->allocate_min<gvar> ();
+    if (unlikely (!out)) return_trace (false);
+
+    out->version.major = 1;
+    out->version.minor = 0;
+    out->axisCount = axisCount;
+    out->sharedTupleCount = sharedTupleCount;
+
+    unsigned int num_glyphs = c->plan->num_output_glyphs ();
+    out->glyphCountX = hb_min (0xFFFFu, num_glyphs);
+
+    auto it = hb_iter (c->plan->new_to_old_gid_list);
+    if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
+      it++;
+    unsigned int subset_data_size = 0;
+    for (auto &_ : it)
+    {
+      hb_codepoint_t old_gid = _.second;
+      subset_data_size += get_glyph_var_data_bytes (c->source_blob, glyph_count, old_gid).length;
+    }
+
+    bool long_offset = (subset_data_size & ~0xFFFFu);
+ #ifdef HB_EXPERIMENTAL_API
+    long_offset = long_offset || (c->plan->flags & HB_SUBSET_FLAGS_IFTB_REQUIREMENTS);
+#endif
+    out->flags = long_offset ? 1 : 0;
+
+    HBUINT8 *subset_offsets = c->serializer->allocate_size<HBUINT8> ((long_offset ? 4 : 2) * (num_glyphs + 1), false);
+    if (!subset_offsets) return_trace (false);
+
+    /* shared tuples */
+    if (!sharedTupleCount || !sharedTuples)
+      out->sharedTuples = 0;
+    else
+    {
+      unsigned int shared_tuple_size = F2DOT14::static_size * axisCount * sharedTupleCount;
+      F2DOT14 *tuples = c->serializer->allocate_size<F2DOT14> (shared_tuple_size);
+      if (!tuples) return_trace (false);
+      out->sharedTuples = (char *) tuples - (char *) out;
+      hb_memcpy (tuples, this+sharedTuples, shared_tuple_size);
+    }
+
+    /* This ordering relative to the shared tuples array, which puts the glyphVariationData
+       last in the table, is required when HB_SUBSET_FLAGS_IFTB_REQUIREMENTS is set */
+    char *subset_data = c->serializer->allocate_size<char> (subset_data_size, false);
+    if (!subset_data) return_trace (false);
+    out->dataZ = subset_data - (char *) out;
+
+
+    if (long_offset)
+    {
+      ((HBUINT32 *) subset_offsets)[0] = 0;
+      subset_offsets += 4;
+    }
+    else
+    {
+      ((HBUINT16 *) subset_offsets)[0] = 0;
+      subset_offsets += 2;
+    }
+    unsigned int glyph_offset = 0;
+
+    hb_codepoint_t last = 0;
+    it = hb_iter (c->plan->new_to_old_gid_list);
+    if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
+      it++;
+    for (auto &_ : it)
+    {
+      hb_codepoint_t gid = _.first;
+      hb_codepoint_t old_gid = _.second;
+
+      if (long_offset)
+	for (; last < gid; last++)
+	  ((HBUINT32 *) subset_offsets)[last] = glyph_offset;
+      else
+	for (; last < gid; last++)
+	  ((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;
+
+      hb_bytes_t var_data_bytes = get_glyph_var_data_bytes (c->source_blob,
+							    glyph_count,
+							    old_gid);
+
+      hb_memcpy (subset_data, var_data_bytes.arrayZ, var_data_bytes.length);
+      subset_data += var_data_bytes.length;
+      glyph_offset += var_data_bytes.length;
+
+      if (long_offset)
+	((HBUINT32 *) subset_offsets)[gid] = glyph_offset;
+      else
+	((HBUINT16 *) subset_offsets)[gid] = glyph_offset / 2;
+
+      last++; // Skip over gid
+    }
+
+    if (long_offset)
+      for (; last < num_glyphs; last++)
+	((HBUINT32 *) subset_offsets)[last] = glyph_offset;
+    else
+      for (; last < num_glyphs; last++)
+	((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;
+
+    return_trace (true);
+  }
+
+  protected:
+  const hb_bytes_t get_glyph_var_data_bytes (hb_blob_t *blob,
+					     unsigned glyph_count,
+					     hb_codepoint_t glyph) const
+  {
+    unsigned start_offset = get_offset (glyph_count, glyph);
+    unsigned end_offset = get_offset (glyph_count, glyph+1);
+    if (unlikely (end_offset < start_offset)) return hb_bytes_t ();
+    unsigned length = end_offset - start_offset;
+    hb_bytes_t var_data = blob->as_bytes ().sub_array (((unsigned) dataZ) + start_offset, length);
+    return likely (var_data.length >= GlyphVariationData::min_size) ? var_data : hb_bytes_t ();
+  }
+
+  bool is_long_offset () const { return flags & 1; }
+
+  unsigned get_offset (unsigned glyph_count, unsigned i) const
+  {
+    if (unlikely (i > glyph_count)) return 0;
+    _hb_compiler_memory_r_barrier ();
+    return is_long_offset () ? get_long_offset_array ()[i] : get_short_offset_array ()[i] * 2;
+  }
+
+  const HBUINT32 * get_long_offset_array () const { return (const HBUINT32 *) &offsetZ; }
+  const HBUINT16 *get_short_offset_array () const { return (const HBUINT16 *) &offsetZ; }
+
+  public:
+  struct accelerator_t
+  {
+    accelerator_t (hb_face_t *face)
+    {
+      table = hb_sanitize_context_t ().reference_table<gvar> (face);
+      /* If sanitize failed, set glyphCount to 0. */
+      glyphCount = table->version.to_int () ? face->get_num_glyphs () : 0;
+
+      /* For shared tuples that only have one axis active, shared the index of
+       * that axis as a cache. This will speed up caclulate_scalar() a lot
+       * for fonts with lots of axes and many "monovar" tuples. */
+      hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * table->axisCount);
+      unsigned count = table->sharedTupleCount;
+      if (unlikely (!shared_tuple_active_idx.resize (count, false))) return;
+      unsigned axis_count = table->axisCount;
+      for (unsigned i = 0; i < count; i++)
+      {
+	hb_array_t<const F2DOT14> tuple = shared_tuples.sub_array (axis_count * i, axis_count);
+	int idx1 = -1, idx2 = -1;
+	for (unsigned j = 0; j < axis_count; j++)
+	{
+	  const F2DOT14 &peak = tuple.arrayZ[j];
+	  if (peak.to_int () != 0)
+	  {
+	    if (idx1 == -1)
+	      idx1 = j;
+	    else if (idx2 == -1)
+	      idx2 = j;
+	    else
+	    {
+	      idx1 = idx2 = -1;
+	      break;
+	    }
+	  }
+	}
+	shared_tuple_active_idx.arrayZ[i] = {idx1, idx2};
+      }
+    }
+    ~accelerator_t () { table.destroy (); }
+
+    private:
+
+    static float infer_delta (const hb_array_t<contour_point_t> points,
+			      const hb_array_t<contour_point_t> deltas,
+			      unsigned int target, unsigned int prev, unsigned int next,
+			      float contour_point_t::*m)
+    {
+      float target_val = points.arrayZ[target].*m;
+      float prev_val = points.arrayZ[prev].*m;
+      float next_val = points.arrayZ[next].*m;
+      float prev_delta =  deltas.arrayZ[prev].*m;
+      float next_delta =  deltas.arrayZ[next].*m;
+
+      if (prev_val == next_val)
+	return (prev_delta == next_delta) ? prev_delta : 0.f;
+      else if (target_val <= hb_min (prev_val, next_val))
+	return (prev_val < next_val) ? prev_delta : next_delta;
+      else if (target_val >= hb_max (prev_val, next_val))
+	return (prev_val > next_val) ? prev_delta : next_delta;
+
+      /* linear interpolation */
+      float r = (target_val - prev_val) / (next_val - prev_val);
+      return prev_delta + r * (next_delta - prev_delta);
+    }
+
+    static unsigned int next_index (unsigned int i, unsigned int start, unsigned int end)
+    { return (i >= end) ? start : (i + 1); }
+
+    public:
+    bool apply_deltas_to_points (hb_codepoint_t glyph,
+				 hb_array_t<int> coords,
+				 const hb_array_t<contour_point_t> points,
+				 bool phantom_only = false) const
+    {
+      if (unlikely (glyph >= glyphCount)) return true;
+
+      hb_bytes_t var_data_bytes = table->get_glyph_var_data_bytes (table.get_blob (), glyphCount, glyph);
+      if (!var_data_bytes.as<GlyphVariationData> ()->has_data ()) return true;
+      hb_vector_t<unsigned int> shared_indices;
+      GlyphVariationData::tuple_iterator_t iterator;
+      if (!GlyphVariationData::get_tuple_iterator (var_data_bytes, table->axisCount,
+						   var_data_bytes.arrayZ,
+						   shared_indices, &iterator))
+	return true; /* so isn't applied at all */
+
+      /* Save original points for inferred delta calculation */
+      contour_point_vector_t orig_points_vec; // Populated lazily
+      auto orig_points = orig_points_vec.as_array ();
+
+      /* flag is used to indicate referenced point */
+      contour_point_vector_t deltas_vec; // Populated lazily
+      auto deltas = deltas_vec.as_array ();
+
+      hb_vector_t<unsigned> end_points; // Populated lazily
+
+      unsigned num_coords = table->axisCount;
+      hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * num_coords);
+
+      hb_vector_t<unsigned int> private_indices;
+      hb_vector_t<int> x_deltas;
+      hb_vector_t<int> y_deltas;
+      unsigned count = points.length;
+      bool flush = false;
+      do
+      {
+	float scalar = iterator.current_tuple->calculate_scalar (coords, num_coords, shared_tuples,
+								 &shared_tuple_active_idx);
+	if (scalar == 0.f) continue;
+	const HBUINT8 *p = iterator.get_serialized_data ();
+	unsigned int length = iterator.current_tuple->get_data_size ();
+	if (unlikely (!iterator.var_data_bytes.check_range (p, length)))
+	  return false;
+
+	if (!deltas)
+	{
+	  if (unlikely (!deltas_vec.resize (count, false))) return false;
+	  deltas = deltas_vec.as_array ();
+	  hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
+		     (phantom_only ? 4 : count) * sizeof (deltas[0]));
+	}
+
+	const HBUINT8 *end = p + length;
+
+	bool has_private_points = iterator.current_tuple->has_private_points ();
+	if (has_private_points &&
+	    !GlyphVariationData::unpack_points (p, private_indices, end))
+	  return false;
+	const hb_array_t<unsigned int> &indices = has_private_points ? private_indices : shared_indices;
+
+	bool apply_to_all = (indices.length == 0);
+	unsigned int num_deltas = apply_to_all ? points.length : indices.length;
+	if (unlikely (!x_deltas.resize (num_deltas, false))) return false;
+	if (unlikely (!GlyphVariationData::unpack_deltas (p, x_deltas, end))) return false;
+	if (unlikely (!y_deltas.resize (num_deltas, false))) return false;
+	if (unlikely (!GlyphVariationData::unpack_deltas (p, y_deltas, end))) return false;
+
+	if (!apply_to_all)
+	{
+	  if (!orig_points && !phantom_only)
+	  {
+	    orig_points_vec.extend (points);
+	    if (unlikely (orig_points_vec.in_error ())) return false;
+	    orig_points = orig_points_vec.as_array ();
+	  }
+
+	  if (flush)
+	  {
+	    for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
+	      points.arrayZ[i].translate (deltas.arrayZ[i]);
+	    flush = false;
+
+	  }
+	  hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
+		     (phantom_only ? 4 : count) * sizeof (deltas[0]));
+	}
+
+	if (HB_OPTIMIZE_SIZE_VAL)
+	{
+	  for (unsigned int i = 0; i < num_deltas; i++)
+	  {
+	    unsigned int pt_index;
+	    if (apply_to_all)
+	      pt_index = i;
+	    else
+	    {
+	      pt_index = indices[i];
+	      if (unlikely (pt_index >= deltas.length)) continue;
+	    }
+	    if (phantom_only && pt_index < count - 4) continue;
+	    auto &delta = deltas.arrayZ[pt_index];
+	    delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
+	    delta.x += x_deltas.arrayZ[i] * scalar;
+	    delta.y += y_deltas.arrayZ[i] * scalar;
+	  }
+	}
+	else
+	{
+	  /* Ouch. Four cases... for optimization. */
+	  if (scalar != 1.0f)
+	  {
+	    if (apply_to_all)
+	      for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
+	      {
+		unsigned int pt_index = i;
+		auto &delta = deltas.arrayZ[pt_index];
+		delta.x += x_deltas.arrayZ[i] * scalar;
+		delta.y += y_deltas.arrayZ[i] * scalar;
+	      }
+	    else
+	      for (unsigned int i = 0; i < num_deltas; i++)
+	      {
+		unsigned int pt_index = indices[i];
+		if (unlikely (pt_index >= deltas.length)) continue;
+		if (phantom_only && pt_index < count - 4) continue;
+		auto &delta = deltas.arrayZ[pt_index];
+		delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
+		delta.x += x_deltas.arrayZ[i] * scalar;
+		delta.y += y_deltas.arrayZ[i] * scalar;
+	      }
+	  }
+	  else
+	  {
+	    if (apply_to_all)
+	      for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
+	      {
+		unsigned int pt_index = i;
+		auto &delta = deltas.arrayZ[pt_index];
+		delta.x += x_deltas.arrayZ[i];
+		delta.y += y_deltas.arrayZ[i];
+	      }
+	    else
+	      for (unsigned int i = 0; i < num_deltas; i++)
+	      {
+		unsigned int pt_index = indices[i];
+		if (unlikely (pt_index >= deltas.length)) continue;
+		if (phantom_only && pt_index < count - 4) continue;
+		auto &delta = deltas.arrayZ[pt_index];
+		delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
+		delta.x += x_deltas.arrayZ[i];
+		delta.y += y_deltas.arrayZ[i];
+	      }
+	  }
+	}
+
+	/* infer deltas for unreferenced points */
+	if (!apply_to_all && !phantom_only)
+	{
+	  if (!end_points)
+	  {
+	    for (unsigned i = 0; i < count; ++i)
+	      if (points.arrayZ[i].is_end_point)
+		end_points.push (i);
+	    if (unlikely (end_points.in_error ())) return false;
+	  }
+
+	  unsigned start_point = 0;
+	  for (unsigned end_point : end_points)
+	  {
+	    /* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */
+	    unsigned unref_count = 0;
+	    for (unsigned i = start_point; i < end_point + 1; i++)
+	      unref_count += deltas.arrayZ[i].flag;
+	    unref_count = (end_point - start_point + 1) - unref_count;
+
+	    unsigned j = start_point;
+	    if (unref_count == 0 || unref_count > end_point - start_point)
+	      goto no_more_gaps;
+
+	    for (;;)
+	    {
+	      /* Locate the next gap of unreferenced points between two referenced points prev and next.
+	       * Note that a gap may wrap around at left (start_point) and/or at right (end_point).
+	       */
+	      unsigned int prev, next, i;
+	      for (;;)
+	      {
+		i = j;
+		j = next_index (i, start_point, end_point);
+		if (deltas.arrayZ[i].flag && !deltas.arrayZ[j].flag) break;
+	      }
+	      prev = j = i;
+	      for (;;)
+	      {
+		i = j;
+		j = next_index (i, start_point, end_point);
+		if (!deltas.arrayZ[i].flag && deltas.arrayZ[j].flag) break;
+	      }
+	      next = j;
+	      /* Infer deltas for all unref points in the gap between prev and next */
+	      i = prev;
+	      for (;;)
+	      {
+		i = next_index (i, start_point, end_point);
+		if (i == next) break;
+		deltas.arrayZ[i].x = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::x);
+		deltas.arrayZ[i].y = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::y);
+		if (--unref_count == 0) goto no_more_gaps;
+	      }
+	    }
+	  no_more_gaps:
+	    start_point = end_point + 1;
+	  }
+	}
+
+	flush = true;
+
+      } while (iterator.move_to_next ());
+
+      if (flush)
+      {
+	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
+	  points.arrayZ[i].translate (deltas.arrayZ[i]);
+      }
+
+      return true;
+    }
+
+    unsigned int get_axis_count () const { return table->axisCount; }
+
+    private:
+    hb_blob_ptr_t<gvar> table;
+    unsigned glyphCount;
+    hb_vector_t<hb_pair_t<int, int>> shared_tuple_active_idx;
+  };
+
+  protected:
+  FixedVersion<>version;	/* Version number of the glyph variations table
+				 * Set to 0x00010000u. */
+  HBUINT16	axisCount;	/* The number of variation axes for this font. This must be
+				 * the same number as axisCount in the 'fvar' table. */
+  HBUINT16	sharedTupleCount;
+				/* The number of shared tuple records. Shared tuple records
+				 * can be referenced within glyph variation data tables for
+				 * multiple glyphs, as opposed to other tuple records stored
+				 * directly within a glyph variation data table. */
+  NNOffset32To<UnsizedArrayOf<F2DOT14>>
+		sharedTuples;	/* Offset from the start of this table to the shared tuple records.
+				 * Array of tuple records shared across all glyph variation data tables. */
+  HBUINT16	glyphCountX;	/* The number of glyphs in this font. This must match the number of
+				 * glyphs stored elsewhere in the font. */
+  HBUINT16	flags;		/* Bit-field that gives the format of the offset array that follows.
+				 * If bit 0 is clear, the offsets are uint16; if bit 0 is set, the
+				 * offsets are uint32. */
+  Offset32To<GlyphVariationData>
+		dataZ;		/* Offset from the start of this table to the array of
+				 * GlyphVariationData tables. */
+  UnsizedArrayOf<HBUINT8>
+		offsetZ;	/* Offsets from the start of the GlyphVariationData array
+				 * to each GlyphVariationData table. */
+  public:
+  DEFINE_SIZE_ARRAY (20, offsetZ);
+};
+
+struct gvar_accelerator_t : gvar::accelerator_t {
+  gvar_accelerator_t (hb_face_t *face) : gvar::accelerator_t (face) {}
+};
+
+} /* namespace OT */
+
+#endif /* HB_OT_VAR_GVAR_TABLE_HH */