--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/hb-subset-plan.cc	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,1107 @@
+/*
+ * Copyright © 2018  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Garret Rieger, Roderick Sheeter
+ */
+
+#include "hb-subset-plan.hh"
+#include "hb-subset-accelerator.hh"
+#include "hb-map.hh"
+#include "hb-multimap.hh"
+#include "hb-set.hh"
+
+#include "hb-ot-cmap-table.hh"
+#include "hb-ot-glyf-table.hh"
+#include "hb-ot-layout-gdef-table.hh"
+#include "hb-ot-layout-gpos-table.hh"
+#include "hb-ot-layout-gsub-table.hh"
+#include "hb-ot-cff1-table.hh"
+#include "hb-ot-color-colr-table.hh"
+#include "hb-ot-color-colrv1-closure.hh"
+#include "hb-ot-var-fvar-table.hh"
+#include "hb-ot-var-avar-table.hh"
+#include "hb-ot-stat-table.hh"
+#include "hb-ot-math-table.hh"
+
+using OT::Layout::GSUB;
+using OT::Layout::GPOS;
+
+typedef hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> script_langsys_map;
+#ifndef HB_NO_SUBSET_CFF
+static inline bool
+_add_cff_seac_components (const OT::cff1::accelerator_t &cff,
+			  hb_codepoint_t gid,
+			  hb_set_t *gids_to_retain)
+{
+  hb_codepoint_t base_gid, accent_gid;
+  if (cff.get_seac_components (gid, &base_gid, &accent_gid))
+  {
+    gids_to_retain->add (base_gid);
+    gids_to_retain->add (accent_gid);
+    return true;
+  }
+  return false;
+}
+#endif
+
+static void
+_remap_palette_indexes (const hb_set_t *palette_indexes,
+			hb_map_t       *mapping /* OUT */)
+{
+  unsigned new_idx = 0;
+  for (unsigned palette_index : palette_indexes->iter ())
+  {
+    if (palette_index == 0xFFFF)
+    {
+      mapping->set (palette_index, palette_index);
+      continue;
+    }
+    mapping->set (palette_index, new_idx);
+    new_idx++;
+  }
+}
+
+static void
+_remap_indexes (const hb_set_t *indexes,
+		hb_map_t       *mapping /* OUT */)
+{
+  for (auto _ : + hb_enumerate (indexes->iter ()))
+    mapping->set (_.second, _.first);
+
+}
+
+#ifndef HB_NO_SUBSET_LAYOUT
+
+/*
+ * Removes all tags from 'tags' that are not in filter. Additionally eliminates any duplicates.
+ * Returns true if anything was removed (not including duplicates).
+ */
+static bool _filter_tag_list(hb_vector_t<hb_tag_t>* tags, /* IN/OUT */
+                             const hb_set_t* filter)
+{
+  hb_vector_t<hb_tag_t> out;
+  out.alloc (tags->get_size() + 1); // +1 is to allocate room for the null terminator.
+
+  bool removed = false;
+  hb_set_t visited;
+
+  for (hb_tag_t tag : *tags)
+  {
+    if (!tag) continue;
+    if (visited.has (tag)) continue;
+
+    if (!filter->has (tag))
+    {
+      removed = true;
+      continue;
+    }
+
+    visited.add (tag);
+    out.push (tag);
+  }
+
+  // The collect function needs a null element to signal end of the array.
+  out.push (HB_TAG_NONE);
+
+  hb_swap (out, *tags);
+  return removed;
+}
+
+template <typename T>
+static void _collect_layout_indices (hb_subset_plan_t     *plan,
+                                     const T&              table,
+                                     hb_set_t		  *lookup_indices, /* OUT */
+                                     hb_set_t		  *feature_indices, /* OUT */
+                                     hb_hashmap_t<unsigned, hb::shared_ptr<hb_set_t>> *feature_record_cond_idx_map, /* OUT */
+                                     hb_hashmap_t<unsigned, const OT::Feature*> *feature_substitutes_map /* OUT */)
+{
+  unsigned num_features = table.get_feature_count ();
+  hb_vector_t<hb_tag_t> features;
+  if (!plan->check_success (features.resize (num_features))) return;
+  table.get_feature_tags (0, &num_features, features.arrayZ);
+  bool retain_all_features = !_filter_tag_list (&features, plan->layout_features);
+
+  unsigned num_scripts = table.get_script_count ();
+  hb_vector_t<hb_tag_t> scripts;
+  if (!plan->check_success (scripts.resize (num_scripts))) return;
+  table.get_script_tags (0, &num_scripts, scripts.arrayZ);
+  bool retain_all_scripts = !_filter_tag_list (&scripts, plan->layout_scripts);
+
+  if (!plan->check_success (!features.in_error ()) || !features
+      || !plan->check_success (!scripts.in_error ()) || !scripts)
+    return;
+
+  hb_ot_layout_collect_features (plan->source,
+                                 T::tableTag,
+                                 retain_all_scripts ? nullptr : scripts.arrayZ,
+                                 nullptr,
+                                 retain_all_features ? nullptr : features.arrayZ,
+                                 feature_indices);
+
+#ifndef HB_NO_VAR
+  // collect feature substitutes with variations
+  if (!plan->user_axes_location->is_empty ())
+  {
+    hb_hashmap_t<hb::shared_ptr<hb_map_t>, unsigned> conditionset_map;
+    OT::hb_collect_feature_substitutes_with_var_context_t c =
+    {
+      plan->axes_old_index_tag_map,
+      plan->axes_location,
+      feature_record_cond_idx_map,
+      feature_substitutes_map,
+      feature_indices,
+      true,
+      0,
+      &conditionset_map
+    };
+    table.collect_feature_substitutes_with_variations (&c);
+  }
+#endif
+
+  for (unsigned feature_index : *feature_indices)
+  {
+    const OT::Feature* f = &(table.get_feature (feature_index));
+    const OT::Feature **p = nullptr;
+    if (feature_substitutes_map->has (feature_index, &p))
+      f = *p;
+
+    f->add_lookup_indexes_to (lookup_indices);
+  }
+
+  table.feature_variation_collect_lookups (feature_indices, feature_substitutes_map, lookup_indices);
+}
+
+
+static inline void
+_GSUBGPOS_find_duplicate_features (const OT::GSUBGPOS &g,
+				   const hb_map_t *lookup_indices,
+				   const hb_set_t *feature_indices,
+				   const hb_hashmap_t<unsigned, const OT::Feature*> *feature_substitutes_map,
+				   hb_map_t *duplicate_feature_map /* OUT */)
+{
+  if (feature_indices->is_empty ()) return;
+  hb_hashmap_t<hb_tag_t, hb::unique_ptr<hb_set_t>> unique_features;
+  //find out duplicate features after subset
+  for (unsigned i : feature_indices->iter ())
+  {
+    hb_tag_t t = g.get_feature_tag (i);
+    if (t == HB_MAP_VALUE_INVALID) continue;
+    if (!unique_features.has (t))
+    {
+      if (unlikely (!unique_features.set (t, hb::unique_ptr<hb_set_t> {hb_set_create ()})))
+	return;
+      if (unique_features.has (t))
+	unique_features.get (t)->add (i);
+      duplicate_feature_map->set (i, i);
+      continue;
+    }
+
+    bool found = false;
+
+    hb_set_t* same_tag_features = unique_features.get (t);
+    for (unsigned other_f_index : same_tag_features->iter ())
+    {
+      const OT::Feature* f = &(g.get_feature (i));
+      const OT::Feature **p = nullptr;
+      if (feature_substitutes_map->has (i, &p))
+        f = *p;
+
+      const OT::Feature* other_f = &(g.get_feature (other_f_index));
+      if (feature_substitutes_map->has (other_f_index, &p))
+        f = *p;
+
+      auto f_iter =
+      + hb_iter (f->lookupIndex)
+      | hb_filter (lookup_indices)
+      ;
+
+      auto other_f_iter =
+      + hb_iter (other_f->lookupIndex)
+      | hb_filter (lookup_indices)
+      ;
+
+      bool is_equal = true;
+      for (; f_iter && other_f_iter; f_iter++, other_f_iter++)
+      {
+	unsigned a = *f_iter;
+	unsigned b = *other_f_iter;
+	if (a != b) { is_equal = false; break; }
+      }
+
+      if (is_equal == false || f_iter || other_f_iter) continue;
+
+      found = true;
+      duplicate_feature_map->set (i, other_f_index);
+      break;
+    }
+
+    if (found == false)
+    {
+      same_tag_features->add (i);
+      duplicate_feature_map->set (i, i);
+    }
+  }
+}
+
+template <typename T>
+static inline void
+_closure_glyphs_lookups_features (hb_subset_plan_t   *plan,
+				  hb_set_t	     *gids_to_retain,
+				  hb_map_t	     *lookups,
+				  hb_map_t	     *features,
+				  script_langsys_map *langsys_map,
+				  hb_hashmap_t<unsigned, hb::shared_ptr<hb_set_t>> *feature_record_cond_idx_map,
+				  hb_hashmap_t<unsigned, const OT::Feature*> *feature_substitutes_map)
+{
+  hb_blob_ptr_t<T> table = plan->source_table<T> ();
+  hb_tag_t table_tag = table->tableTag;
+  hb_set_t lookup_indices, feature_indices;
+  _collect_layout_indices<T> (plan,
+                              *table,
+                              &lookup_indices,
+                              &feature_indices,
+                              feature_record_cond_idx_map,
+                              feature_substitutes_map);
+
+  if (table_tag == HB_OT_TAG_GSUB)
+    hb_ot_layout_lookups_substitute_closure (plan->source,
+                                             &lookup_indices,
+					     gids_to_retain);
+  table->closure_lookups (plan->source,
+			  gids_to_retain,
+                          &lookup_indices);
+  _remap_indexes (&lookup_indices, lookups);
+
+  // prune features
+  table->prune_features (lookups,
+                         plan->user_axes_location->is_empty () ? nullptr : feature_record_cond_idx_map,
+                         feature_substitutes_map,
+                         &feature_indices);
+  hb_map_t duplicate_feature_map;
+  _GSUBGPOS_find_duplicate_features (*table, lookups, &feature_indices, feature_substitutes_map, &duplicate_feature_map);
+
+  feature_indices.clear ();
+  table->prune_langsys (&duplicate_feature_map, plan->layout_scripts, langsys_map, &feature_indices);
+  _remap_indexes (&feature_indices, features);
+
+  table.destroy ();
+}
+
+#endif
+
+#ifndef HB_NO_VAR
+static inline void
+_generate_varstore_inner_maps (const hb_set_t& varidx_set,
+                               unsigned subtable_count,
+                               hb_vector_t<hb_inc_bimap_t> &inner_maps /* OUT */)
+{
+  if (varidx_set.is_empty () || subtable_count == 0) return;
+
+  inner_maps.resize (subtable_count);
+  for (unsigned idx : varidx_set)
+  {
+    uint16_t major = idx >> 16;
+    uint16_t minor = idx & 0xFFFF;
+
+    if (major >= subtable_count)
+      continue;
+    inner_maps[major].add (minor);
+  }
+}
+
+static inline hb_font_t*
+_get_hb_font_with_variations (const hb_subset_plan_t *plan)
+{
+  hb_font_t *font = hb_font_create (plan->source);
+
+  hb_vector_t<hb_variation_t> vars;
+  vars.alloc (plan->user_axes_location->get_population ());
+
+  for (auto _ : *plan->user_axes_location)
+  {
+    hb_variation_t var;
+    var.tag = _.first;
+    var.value = _.second;
+    vars.push (var);
+  }
+
+#ifndef HB_NO_VAR
+  hb_font_set_variations (font, vars.arrayZ, plan->user_axes_location->get_population ());
+#endif
+  return font;
+}
+
+static inline void
+_collect_layout_variation_indices (hb_subset_plan_t* plan)
+{
+  hb_blob_ptr_t<OT::GDEF> gdef = plan->source_table<OT::GDEF> ();
+  hb_blob_ptr_t<GPOS> gpos = plan->source_table<GPOS> ();
+
+  if (!gdef->has_data ())
+  {
+    gdef.destroy ();
+    gpos.destroy ();
+    return;
+  }
+
+  const OT::VariationStore *var_store = nullptr;
+  hb_set_t varidx_set;
+  hb_font_t *font = nullptr;
+  float *store_cache = nullptr;
+  bool collect_delta = plan->pinned_at_default ? false : true;
+  if (collect_delta)
+  {
+    font = _get_hb_font_with_variations (plan);
+    if (gdef->has_var_store ())
+    {
+      var_store = &(gdef->get_var_store ());
+      store_cache = var_store->create_cache ();
+    }
+  }
+
+  OT::hb_collect_variation_indices_context_t c (&varidx_set,
+                                                plan->layout_variation_idx_delta_map,
+                                                font, var_store,
+                                                plan->_glyphset_gsub,
+                                                plan->gpos_lookups,
+                                                store_cache);
+  gdef->collect_variation_indices (&c);
+
+  if (hb_ot_layout_has_positioning (plan->source))
+    gpos->collect_variation_indices (&c);
+
+  hb_font_destroy (font);
+  var_store->destroy_cache (store_cache);
+
+  gdef->remap_layout_variation_indices (&varidx_set, plan->layout_variation_idx_delta_map);
+
+  unsigned subtable_count = gdef->has_var_store () ? gdef->get_var_store ().get_sub_table_count () : 0;
+  _generate_varstore_inner_maps (varidx_set, subtable_count, plan->gdef_varstore_inner_maps);
+
+  gdef.destroy ();
+  gpos.destroy ();
+}
+#endif
+
+static inline void
+_cmap_closure (hb_face_t	   *face,
+	       const hb_set_t	   *unicodes,
+	       hb_set_t		   *glyphset)
+{
+  OT::cmap::accelerator_t cmap (face);
+  cmap.table->closure_glyphs (unicodes, glyphset);
+}
+
+static void _colr_closure (hb_face_t *face,
+                           hb_map_t *layers_map,
+                           hb_map_t *palettes_map,
+                           hb_set_t *glyphs_colred)
+{
+  OT::COLR::accelerator_t colr (face);
+  if (!colr.is_valid ()) return;
+
+  hb_set_t palette_indices, layer_indices;
+  // Collect all glyphs referenced by COLRv0
+  hb_set_t glyphset_colrv0;
+  for (hb_codepoint_t gid : *glyphs_colred)
+    colr.closure_glyphs (gid, &glyphset_colrv0);
+
+  glyphs_colred->union_ (glyphset_colrv0);
+
+  //closure for COLRv1
+  colr.closure_forV1 (glyphs_colred, &layer_indices, &palette_indices);
+
+  colr.closure_V0palette_indices (glyphs_colred, &palette_indices);
+  _remap_indexes (&layer_indices, layers_map);
+  _remap_palette_indexes (&palette_indices, palettes_map);
+}
+
+static inline void
+_math_closure (hb_subset_plan_t *plan,
+               hb_set_t         *glyphset)
+{
+  hb_blob_ptr_t<OT::MATH> math = plan->source_table<OT::MATH> ();
+  if (math->has_data ())
+    math->closure_glyphs (glyphset);
+  math.destroy ();
+}
+
+
+static inline void
+_remove_invalid_gids (hb_set_t *glyphs,
+		      unsigned int num_glyphs)
+{
+  glyphs->del_range (num_glyphs, HB_SET_VALUE_INVALID);
+}
+
+static void
+_populate_unicodes_to_retain (const hb_set_t *unicodes,
+                              const hb_set_t *glyphs,
+                              hb_subset_plan_t *plan)
+{
+  OT::cmap::accelerator_t cmap (plan->source);
+  unsigned size_threshold = plan->source->get_num_glyphs ();
+  if (glyphs->is_empty () && unicodes->get_population () < size_threshold)
+  {
+
+    const hb_map_t* unicode_to_gid = nullptr;
+    if (plan->accelerator)
+      unicode_to_gid = &plan->accelerator->unicode_to_gid;
+
+    // This is approach to collection is faster, but can only be used  if glyphs
+    // are not being explicitly added to the subset and the input unicodes set is
+    // not excessively large (eg. an inverted set).
+    plan->unicode_to_new_gid_list.alloc (unicodes->get_population ());
+    if (!unicode_to_gid) {
+      for (hb_codepoint_t cp : *unicodes)
+      {
+        hb_codepoint_t gid;
+        if (!cmap.get_nominal_glyph (cp, &gid))
+        {
+          DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
+          continue;
+        }
+
+        plan->codepoint_to_glyph->set (cp, gid);
+        plan->unicode_to_new_gid_list.push (hb_pair (cp, gid));
+      }
+    } else {
+      // Use in memory unicode to gid map it's faster then looking up from
+      // the map. This code is mostly duplicated from above to avoid doing
+      // conditionals on the presence of the unicode_to_gid map each
+      // iteration.
+      for (hb_codepoint_t cp : *unicodes)
+      {
+        hb_codepoint_t gid = unicode_to_gid->get (cp);
+        if (gid == HB_MAP_VALUE_INVALID)
+        {
+          DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
+          continue;
+        }
+
+        plan->codepoint_to_glyph->set (cp, gid);
+        plan->unicode_to_new_gid_list.push (hb_pair (cp, gid));
+      }
+    }
+  }
+  else
+  {
+    // This approach is slower, but can handle adding in glyphs to the subset and will match
+    // them with cmap entries.
+
+    hb_map_t unicode_glyphid_map_storage;
+    hb_set_t cmap_unicodes_storage;
+    const hb_map_t* unicode_glyphid_map = &unicode_glyphid_map_storage;
+    const hb_set_t* cmap_unicodes = &cmap_unicodes_storage;
+
+    if (!plan->accelerator) {
+      cmap.collect_mapping (&cmap_unicodes_storage, &unicode_glyphid_map_storage);
+      plan->unicode_to_new_gid_list.alloc (hb_min(unicodes->get_population ()
+                                                  + glyphs->get_population (),
+                                                  cmap_unicodes->get_population ()));
+    } else {
+      unicode_glyphid_map = &plan->accelerator->unicode_to_gid;
+      cmap_unicodes = &plan->accelerator->unicodes;
+    }
+
+    if (plan->accelerator &&
+	unicodes->get_population () < cmap_unicodes->get_population () &&
+	glyphs->get_population () < cmap_unicodes->get_population ())
+    {
+      auto &gid_to_unicodes = plan->accelerator->gid_to_unicodes;
+      for (hb_codepoint_t gid : *glyphs)
+      {
+        auto unicodes = gid_to_unicodes.get (gid);
+
+	for (hb_codepoint_t cp : unicodes)
+	{
+	  plan->codepoint_to_glyph->set (cp, gid);
+	  plan->unicode_to_new_gid_list.push (hb_pair (cp, gid));
+	}
+      }
+      for (hb_codepoint_t cp : *unicodes)
+      {
+	/* Don't double-add entry. */
+	if (plan->codepoint_to_glyph->has (cp))
+	  continue;
+
+	hb_codepoint_t gid = (*unicode_glyphid_map)[cp];
+	plan->codepoint_to_glyph->set (cp, gid);
+	plan->unicode_to_new_gid_list.push (hb_pair (cp, gid));
+      }
+      plan->unicode_to_new_gid_list.qsort ();
+    }
+    else
+    {
+      for (hb_codepoint_t cp : *cmap_unicodes)
+      {
+	hb_codepoint_t gid = (*unicode_glyphid_map)[cp];
+	if (!unicodes->has (cp) && !glyphs->has (gid))
+	  continue;
+
+	plan->codepoint_to_glyph->set (cp, gid);
+	plan->unicode_to_new_gid_list.push (hb_pair (cp, gid));
+      }
+    }
+
+    /* Add gids which where requested, but not mapped in cmap */
+    for (hb_codepoint_t gid : *glyphs)
+    {
+      if (gid >= plan->source->get_num_glyphs ())
+	break;
+      plan->_glyphset_gsub->add (gid);
+    }
+  }
+
+  auto &arr = plan->unicode_to_new_gid_list;
+  if (arr.length)
+  {
+    plan->unicodes->add_sorted_array (&arr.arrayZ->first, arr.length, sizeof (*arr.arrayZ));
+    plan->_glyphset_gsub->add_array (&arr.arrayZ->second, arr.length, sizeof (*arr.arrayZ));
+  }
+}
+
+#ifndef HB_COMPOSITE_OPERATIONS_PER_GLYPH
+#define HB_COMPOSITE_OPERATIONS_PER_GLYPH 64
+#endif
+
+static unsigned
+_glyf_add_gid_and_children (const OT::glyf_accelerator_t &glyf,
+			    hb_codepoint_t gid,
+			    hb_set_t *gids_to_retain,
+			    int operation_count,
+			    unsigned depth = 0)
+{
+  if (unlikely (depth++ > HB_MAX_NESTING_LEVEL)) return operation_count;
+  if (unlikely (--operation_count < 0)) return operation_count;
+  /* Check if is already visited */
+  if (gids_to_retain->has (gid)) return operation_count;
+
+  gids_to_retain->add (gid);
+
+  for (auto item : glyf.glyph_for_gid (gid).get_composite_iterator ())
+    operation_count =
+      _glyf_add_gid_and_children (glyf,
+				  item.get_gid (),
+				  gids_to_retain,
+				  operation_count,
+				  depth);
+
+  return operation_count;
+}
+
+static void
+_populate_gids_to_retain (hb_subset_plan_t* plan,
+		          hb_set_t* drop_tables)
+{
+  OT::glyf_accelerator_t glyf (plan->source);
+#ifndef HB_NO_SUBSET_CFF
+  OT::cff1::accelerator_t cff (plan->source);
+#endif
+
+  plan->_glyphset_gsub->add (0); // Not-def
+
+  _cmap_closure (plan->source, plan->unicodes, plan->_glyphset_gsub);
+
+#ifndef HB_NO_SUBSET_LAYOUT
+  if (!drop_tables->has (HB_OT_TAG_GSUB))
+    // closure all glyphs/lookups/features needed for GSUB substitutions.
+    _closure_glyphs_lookups_features<GSUB> (
+        plan,
+        plan->_glyphset_gsub,
+        plan->gsub_lookups,
+        plan->gsub_features,
+        plan->gsub_langsys,
+        plan->gsub_feature_record_cond_idx_map,
+        plan->gsub_feature_substitutes_map);
+
+  if (!drop_tables->has (HB_OT_TAG_GPOS))
+    _closure_glyphs_lookups_features<GPOS> (
+        plan,
+        plan->_glyphset_gsub,
+        plan->gpos_lookups,
+        plan->gpos_features,
+        plan->gpos_langsys,
+        plan->gpos_feature_record_cond_idx_map,
+        plan->gpos_feature_substitutes_map);
+#endif
+  _remove_invalid_gids (plan->_glyphset_gsub, plan->source->get_num_glyphs ());
+
+  hb_set_set (plan->_glyphset_mathed, plan->_glyphset_gsub);
+  if (!drop_tables->has (HB_OT_TAG_MATH))
+  {
+    _math_closure (plan, plan->_glyphset_mathed);
+    _remove_invalid_gids (plan->_glyphset_mathed, plan->source->get_num_glyphs ());
+  }
+
+  hb_set_t cur_glyphset = *plan->_glyphset_mathed;
+  if (!drop_tables->has (HB_OT_TAG_COLR))
+  {
+    _colr_closure (plan->source, plan->colrv1_layers, plan->colr_palettes, &cur_glyphset);
+    _remove_invalid_gids (&cur_glyphset, plan->source->get_num_glyphs ());
+  }
+
+  hb_set_set (plan->_glyphset_colred, &cur_glyphset);
+
+  /* Populate a full set of glyphs to retain by adding all referenced
+   * composite glyphs. */
+  if (glyf.has_data ())
+    for (hb_codepoint_t gid : cur_glyphset)
+      _glyf_add_gid_and_children (glyf, gid, plan->_glyphset,
+				  cur_glyphset.get_population () * HB_COMPOSITE_OPERATIONS_PER_GLYPH);
+  else
+    plan->_glyphset->union_ (cur_glyphset);
+#ifndef HB_NO_SUBSET_CFF
+  if (!plan->accelerator || plan->accelerator->has_seac)
+  {
+    bool has_seac = false;
+    if (cff.is_valid ())
+      for (hb_codepoint_t gid : cur_glyphset)
+	if (_add_cff_seac_components (cff, gid, plan->_glyphset))
+	  has_seac = true;
+    plan->has_seac = has_seac;
+  }
+#endif
+
+  _remove_invalid_gids (plan->_glyphset, plan->source->get_num_glyphs ());
+
+
+#ifndef HB_NO_VAR
+  if (!drop_tables->has (HB_OT_TAG_GDEF))
+    _collect_layout_variation_indices (plan);
+#endif
+}
+
+static void
+_create_glyph_map_gsub (const hb_set_t* glyph_set_gsub,
+                        const hb_map_t* glyph_map,
+                        hb_map_t* out)
+{
+  + hb_iter (glyph_set_gsub)
+  | hb_map ([&] (hb_codepoint_t gid) {
+    return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (gid,
+                                                      glyph_map->get (gid));
+  })
+  | hb_sink (out)
+  ;
+}
+
+static void
+_create_old_gid_to_new_gid_map (const hb_face_t *face,
+				bool		 retain_gids,
+				const hb_set_t	*all_gids_to_retain,
+				hb_map_t	*glyph_map, /* OUT */
+				hb_map_t	*reverse_glyph_map, /* OUT */
+				unsigned int	*num_glyphs /* OUT */)
+{
+  unsigned pop = all_gids_to_retain->get_population ();
+  reverse_glyph_map->resize (pop);
+  glyph_map->resize (pop);
+
+  if (!retain_gids)
+  {
+    + hb_enumerate (hb_iter (all_gids_to_retain), (hb_codepoint_t) 0)
+    | hb_sink (reverse_glyph_map)
+    ;
+    *num_glyphs = reverse_glyph_map->get_population ();
+  }
+  else
+  {
+    + hb_iter (all_gids_to_retain)
+    | hb_map ([] (hb_codepoint_t _) {
+		return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (_, _);
+	      })
+    | hb_sink (reverse_glyph_map)
+    ;
+
+    hb_codepoint_t max_glyph = HB_SET_VALUE_INVALID;
+    hb_set_previous (all_gids_to_retain, &max_glyph);
+
+    *num_glyphs = max_glyph + 1;
+  }
+
+  + reverse_glyph_map->iter ()
+  | hb_map (&hb_pair_t<hb_codepoint_t, hb_codepoint_t>::reverse)
+  | hb_sink (glyph_map)
+  ;
+}
+
+static void
+_nameid_closure (hb_face_t *face,
+		 hb_set_t  *nameids,
+		 bool all_axes_pinned,
+		 hb_hashmap_t<hb_tag_t, float> *user_axes_location)
+{
+#ifndef HB_NO_STYLE
+  face->table.STAT->collect_name_ids (user_axes_location, nameids);
+#endif
+#ifndef HB_NO_VAR
+  if (!all_axes_pinned)
+    face->table.fvar->collect_name_ids (user_axes_location, nameids);
+#endif
+}
+
+#ifndef HB_NO_VAR
+static void
+_normalize_axes_location (hb_face_t *face, hb_subset_plan_t *plan)
+{
+  if (plan->user_axes_location->is_empty ())
+    return;
+
+  hb_array_t<const OT::AxisRecord> axes = face->table.fvar->get_axes ();
+
+  bool has_avar = face->table.avar->has_data ();
+  const OT::SegmentMaps *seg_maps = nullptr;
+  if (has_avar)
+    seg_maps = face->table.avar->get_segment_maps ();
+
+  bool axis_not_pinned = false;
+  unsigned old_axis_idx = 0, new_axis_idx = 0;
+  for (const auto& axis : axes)
+  {
+    hb_tag_t axis_tag = axis.get_axis_tag ();
+    plan->axes_old_index_tag_map->set (old_axis_idx, axis_tag);
+
+    if (!plan->user_axes_location->has (axis_tag))
+    {
+      axis_not_pinned = true;
+      plan->axes_index_map->set (old_axis_idx, new_axis_idx);
+      new_axis_idx++;
+    }
+    else
+    {
+      int normalized_v = axis.normalize_axis_value (plan->user_axes_location->get (axis_tag));
+      if (has_avar && old_axis_idx < face->table.avar->get_axis_count ())
+      {
+        normalized_v = seg_maps->map (normalized_v);
+      }
+      plan->axes_location->set (axis_tag, normalized_v);
+      if (normalized_v != 0)
+        plan->pinned_at_default = false;
+    }
+    if (has_avar)
+      seg_maps = &StructAfter<OT::SegmentMaps> (*seg_maps);
+
+    old_axis_idx++;
+  }
+  plan->all_axes_pinned = !axis_not_pinned;
+}
+#endif
+/**
+ * hb_subset_plan_create_or_fail:
+ * @face: font face to create the plan for.
+ * @input: a #hb_subset_input_t input.
+ *
+ * Computes a plan for subsetting the supplied face according
+ * to a provided input. The plan describes
+ * which tables and glyphs should be retained.
+ *
+ * Return value: (transfer full): New subset plan. Destroy with
+ * hb_subset_plan_destroy(). If there is a failure creating the plan
+ * nullptr will be returned.
+ *
+ * Since: 4.0.0
+ **/
+hb_subset_plan_t *
+hb_subset_plan_create_or_fail (hb_face_t	 *face,
+                               const hb_subset_input_t *input)
+{
+  hb_subset_plan_t *plan;
+  if (unlikely (!(plan = hb_object_create<hb_subset_plan_t> ())))
+    return nullptr;
+
+  plan->successful = true;
+  plan->flags = input->flags;
+  plan->unicodes = hb_set_create ();
+
+  plan->unicode_to_new_gid_list.init ();
+
+  plan->name_ids = hb_set_copy (input->sets.name_ids);
+  plan->name_languages = hb_set_copy (input->sets.name_languages);
+  plan->layout_features = hb_set_copy (input->sets.layout_features);
+  plan->layout_scripts = hb_set_copy (input->sets.layout_scripts);
+  plan->glyphs_requested = hb_set_copy (input->sets.glyphs);
+  plan->drop_tables = hb_set_copy (input->sets.drop_tables);
+  plan->no_subset_tables = hb_set_copy (input->sets.no_subset_tables);
+  plan->source = hb_face_reference (face);
+  plan->dest = hb_face_builder_create ();
+
+  plan->_glyphset = hb_set_create ();
+  plan->_glyphset_gsub = hb_set_create ();
+  plan->_glyphset_mathed = hb_set_create ();
+  plan->_glyphset_colred = hb_set_create ();
+  plan->codepoint_to_glyph = hb_map_create ();
+  plan->glyph_map = hb_map_create ();
+  plan->reverse_glyph_map = hb_map_create ();
+  plan->glyph_map_gsub = hb_map_create ();
+  plan->gsub_lookups = hb_map_create ();
+  plan->gpos_lookups = hb_map_create ();
+
+  plan->check_success (plan->gsub_langsys = hb_hashmap_create<unsigned, hb::unique_ptr<hb_set_t>> ());
+  plan->check_success (plan->gpos_langsys = hb_hashmap_create<unsigned, hb::unique_ptr<hb_set_t>> ());
+
+  plan->gsub_features = hb_map_create ();
+  plan->gpos_features = hb_map_create ();
+
+  plan->check_success (plan->gsub_feature_record_cond_idx_map = hb_hashmap_create<unsigned, hb::shared_ptr<hb_set_t>> ());
+  plan->check_success (plan->gpos_feature_record_cond_idx_map = hb_hashmap_create<unsigned, hb::shared_ptr<hb_set_t>> ());
+
+  plan->check_success (plan->gsub_feature_substitutes_map = hb_hashmap_create<unsigned, const OT::Feature*> ());
+  plan->check_success (plan->gpos_feature_substitutes_map = hb_hashmap_create<unsigned, const OT::Feature*> ());
+
+  plan->colrv1_layers = hb_map_create ();
+  plan->colr_palettes = hb_map_create ();
+  plan->check_success (plan->layout_variation_idx_delta_map = hb_hashmap_create<unsigned, hb_pair_t<unsigned, int>> ());
+  plan->gdef_varstore_inner_maps.init ();
+
+  plan->check_success (plan->sanitized_table_cache = hb_hashmap_create<hb_tag_t, hb::unique_ptr<hb_blob_t>> ());
+  plan->check_success (plan->axes_location = hb_hashmap_create<hb_tag_t, int> ());
+  plan->check_success (plan->user_axes_location = hb_hashmap_create<hb_tag_t, float> ());
+  if (plan->user_axes_location && input->axes_location)
+      *plan->user_axes_location = *input->axes_location;
+  plan->check_success (plan->axes_index_map = hb_map_create ());
+  plan->check_success (plan->axes_old_index_tag_map = hb_map_create ());
+  plan->all_axes_pinned = false;
+  plan->pinned_at_default = true;
+
+  plan->check_success (plan->vmtx_map = hb_hashmap_create<unsigned, hb_pair_t<unsigned, int>> ());
+  plan->check_success (plan->hmtx_map = hb_hashmap_create<unsigned, hb_pair_t<unsigned, int>> ());
+
+#ifdef HB_EXPERIMENTAL_API
+  plan->check_success (plan->name_table_overrides = hb_hashmap_create<hb_ot_name_record_ids_t, hb_bytes_t> ());
+  if (plan->name_table_overrides && input->name_table_overrides)
+  {
+    for (auto _ : *input->name_table_overrides)
+    {
+      hb_bytes_t name_bytes = _.second;
+      unsigned len = name_bytes.length;
+      char *name_str = (char *) hb_malloc (len);
+      if (unlikely (!plan->check_success (name_str)))
+        break;
+
+      hb_memcpy (name_str, name_bytes.arrayZ, len);
+      plan->name_table_overrides->set (_.first, hb_bytes_t (name_str, len));
+    }
+  }
+#endif
+
+  void* accel = hb_face_get_user_data(face, hb_subset_accelerator_t::user_data_key());
+
+  plan->attach_accelerator_data = input->attach_accelerator_data;
+  plan->force_long_loca = input->force_long_loca;
+  if (accel)
+    plan->accelerator = (hb_subset_accelerator_t*) accel;
+
+
+  if (unlikely (plan->in_error ())) {
+    hb_subset_plan_destroy (plan);
+    return nullptr;
+  }
+
+#ifndef HB_NO_VAR
+  _normalize_axes_location (face, plan);
+#endif
+
+  _populate_unicodes_to_retain (input->sets.unicodes, input->sets.glyphs, plan);
+
+  _populate_gids_to_retain (plan, input->sets.drop_tables);
+
+  _create_old_gid_to_new_gid_map (face,
+                                  input->flags & HB_SUBSET_FLAGS_RETAIN_GIDS,
+				  plan->_glyphset,
+				  plan->glyph_map,
+				  plan->reverse_glyph_map,
+				  &plan->_num_output_glyphs);
+
+  _create_glyph_map_gsub (
+      plan->_glyphset_gsub,
+      plan->glyph_map,
+      plan->glyph_map_gsub);
+
+  // Now that we have old to new gid map update the unicode to new gid list.
+  for (unsigned i = 0; i < plan->unicode_to_new_gid_list.length; i++)
+  {
+    // Use raw array access for performance.
+    plan->unicode_to_new_gid_list.arrayZ[i].second =
+        plan->glyph_map->get(plan->unicode_to_new_gid_list.arrayZ[i].second);
+  }
+
+  _nameid_closure (face, plan->name_ids, plan->all_axes_pinned, plan->user_axes_location);
+  if (unlikely (plan->in_error ())) {
+    hb_subset_plan_destroy (plan);
+    return nullptr;
+  }
+
+
+  if (plan->attach_accelerator_data)
+  {
+    hb_multimap_t gid_to_unicodes;
+
+    hb_map_t &unicode_to_gid = *plan->codepoint_to_glyph;
+
+    for (auto unicode : *plan->unicodes)
+    {
+      auto gid = unicode_to_gid[unicode];
+      gid_to_unicodes.add (gid, unicode);
+    }
+
+    plan->inprogress_accelerator =
+      hb_subset_accelerator_t::create (*plan->codepoint_to_glyph,
+				       gid_to_unicodes,
+                                       *plan->unicodes,
+				       plan->has_seac);
+  }
+
+
+  return plan;
+}
+
+/**
+ * hb_subset_plan_destroy:
+ * @plan: a #hb_subset_plan_t
+ *
+ * Decreases the reference count on @plan, and if it reaches zero, destroys
+ * @plan, freeing all memory.
+ *
+ * Since: 4.0.0
+ **/
+void
+hb_subset_plan_destroy (hb_subset_plan_t *plan)
+{
+  if (!hb_object_destroy (plan)) return;
+
+  hb_free (plan);
+}
+
+/**
+ * hb_subset_plan_old_to_new_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Returns the mapping between glyphs in the original font to glyphs in the
+ * subset that will be produced by @plan
+ *
+ * Return value: (transfer none):
+ * A pointer to the #hb_map_t of the mapping.
+ *
+ * Since: 4.0.0
+ **/
+const hb_map_t*
+hb_subset_plan_old_to_new_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->glyph_map;
+}
+
+/**
+ * hb_subset_plan_new_to_old_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Returns the mapping between glyphs in the subset that will be produced by
+ * @plan and the glyph in the original font.
+ *
+ * Return value: (transfer none):
+ * A pointer to the #hb_map_t of the mapping.
+ *
+ * Since: 4.0.0
+ **/
+const hb_map_t*
+hb_subset_plan_new_to_old_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->reverse_glyph_map;
+}
+
+/**
+ * hb_subset_plan_unicode_to_old_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Returns the mapping between codepoints in the original font and the
+ * associated glyph id in the original font.
+ *
+ * Return value: (transfer none):
+ * A pointer to the #hb_map_t of the mapping.
+ *
+ * Since: 4.0.0
+ **/
+const hb_map_t*
+hb_subset_plan_unicode_to_old_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->codepoint_to_glyph;
+}
+
+/**
+ * hb_subset_plan_reference: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ *
+ * Increases the reference count on @plan.
+ *
+ * Return value: @plan.
+ *
+ * Since: 4.0.0
+ **/
+hb_subset_plan_t *
+hb_subset_plan_reference (hb_subset_plan_t *plan)
+{
+  return hb_object_reference (plan);
+}
+
+/**
+ * hb_subset_plan_set_user_data: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ * @key: The user-data key to set
+ * @data: A pointer to the user data
+ * @destroy: (nullable): A callback to call when @data is not needed anymore
+ * @replace: Whether to replace an existing data with the same key
+ *
+ * Attaches a user-data key/data pair to the given subset plan object.
+ *
+ * Return value: `true` if success, `false` otherwise
+ *
+ * Since: 4.0.0
+ **/
+hb_bool_t
+hb_subset_plan_set_user_data (hb_subset_plan_t   *plan,
+                              hb_user_data_key_t *key,
+                              void               *data,
+                              hb_destroy_func_t   destroy,
+                              hb_bool_t	          replace)
+{
+  return hb_object_set_user_data (plan, key, data, destroy, replace);
+}
+
+/**
+ * hb_subset_plan_get_user_data: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ * @key: The user-data key to query
+ *
+ * Fetches the user data associated with the specified key,
+ * attached to the specified subset plan object.
+ *
+ * Return value: (transfer none): A pointer to the user data
+ *
+ * Since: 4.0.0
+ **/
+void *
+hb_subset_plan_get_user_data (const hb_subset_plan_t *plan,
+                              hb_user_data_key_t     *key)
+{
+  return hb_object_get_user_data (plan, key);
+}