1 files changed, 395 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-subset-plan.cc b/gfx/harfbuzz/src/hb-subset-plan.cc
new file mode 100644
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+++ b/gfx/harfbuzz/src/hb-subset-plan.cc
@@ -0,0 +1,395 @@
+/*
+ * 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-map.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-var-fvar-table.hh"
+#include "hb-ot-stat-table.hh"
+
+
+#ifndef HB_NO_SUBSET_CFF
+static inline void
+_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);
+  }
+}
+#endif
+
+#ifndef HB_NO_SUBSET_LAYOUT
+static void
+_remap_indexes (const hb_set_t *indexes,
+		hb_map_t       *mapping /* OUT */)
+{
+  unsigned count = indexes->get_population ();
+
+  for (auto _ : + hb_zip (indexes->iter (), hb_range (count)))
+    mapping->set (_.first, _.second);
+
+}
+
+static inline void
+_gsub_closure_glyphs_lookups_features (hb_face_t *face,
+				       hb_set_t *gids_to_retain,
+				       hb_map_t *gsub_lookups,
+				       hb_map_t *gsub_features)
+{
+  hb_set_t lookup_indices;
+  hb_ot_layout_collect_lookups (face,
+				HB_OT_TAG_GSUB,
+				nullptr,
+				nullptr,
+				nullptr,
+				&lookup_indices);
+  hb_ot_layout_lookups_substitute_closure (face,
+					   &lookup_indices,
+					   gids_to_retain);
+  hb_blob_ptr_t<OT::GSUB> gsub = hb_sanitize_context_t ().reference_table<OT::GSUB> (face);
+  gsub->closure_lookups (face,
+			 gids_to_retain,
+			 &lookup_indices);
+  _remap_indexes (&lookup_indices, gsub_lookups);
+
+  //closure features
+  hb_set_t feature_indices;
+  gsub->closure_features (gsub_lookups, &feature_indices);
+  _remap_indexes (&feature_indices, gsub_features);
+  gsub.destroy ();
+}
+
+static inline void
+_gpos_closure_lookups_features (hb_face_t      *face,
+				const hb_set_t *gids_to_retain,
+				hb_map_t       *gpos_lookups,
+				hb_map_t       *gpos_features)
+{
+  hb_set_t lookup_indices;
+  hb_ot_layout_collect_lookups (face,
+				HB_OT_TAG_GPOS,
+				nullptr,
+				nullptr,
+				nullptr,
+				&lookup_indices);
+  hb_blob_ptr_t<OT::GPOS> gpos = hb_sanitize_context_t ().reference_table<OT::GPOS> (face);
+  gpos->closure_lookups (face,
+			 gids_to_retain,
+			 &lookup_indices);
+  _remap_indexes (&lookup_indices, gpos_lookups);
+
+  //closure features
+  hb_set_t feature_indices;
+  gpos->closure_features (gpos_lookups, &feature_indices);
+  _remap_indexes (&feature_indices, gpos_features);
+  gpos.destroy ();
+}
+#endif
+
+#ifndef HB_NO_VAR
+static inline void
+  _collect_layout_variation_indices (hb_face_t *face,
+				     const hb_set_t *glyphset,
+				     const hb_map_t *gpos_lookups,
+				     hb_set_t  *layout_variation_indices,
+				     hb_map_t  *layout_variation_idx_map)
+{
+  hb_blob_ptr_t<OT::GDEF> gdef = hb_sanitize_context_t ().reference_table<OT::GDEF> (face);
+  hb_blob_ptr_t<OT::GPOS> gpos = hb_sanitize_context_t ().reference_table<OT::GPOS> (face);
+
+  if (!gdef->has_data ())
+  {
+    gdef.destroy ();
+    gpos.destroy ();
+    return;
+  }
+  OT::hb_collect_variation_indices_context_t c (layout_variation_indices, glyphset, gpos_lookups);
+  gdef->collect_variation_indices (&c);
+
+  if (hb_ot_layout_has_positioning (face))
+    gpos->collect_variation_indices (&c);
+
+  gdef->remap_layout_variation_indices (layout_variation_indices, layout_variation_idx_map);
+
+  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;
+  cmap.init (face);
+  cmap.table->closure_glyphs (unicodes, glyphset);
+  cmap.fini ();
+}
+
+static inline void
+_remove_invalid_gids (hb_set_t *glyphs,
+		      unsigned int num_glyphs)
+{
+  hb_codepoint_t gid = HB_SET_VALUE_INVALID;
+  while (glyphs->next (&gid))
+  {
+    if (gid >= num_glyphs)
+      glyphs->del (gid);
+  }
+}
+
+static void
+_populate_gids_to_retain (hb_subset_plan_t* plan,
+			  const hb_set_t *unicodes,
+			  const hb_set_t *input_glyphs_to_retain,
+			  bool close_over_gsub,
+			  bool close_over_gpos,
+			  bool close_over_gdef)
+{
+  OT::cmap::accelerator_t cmap;
+  OT::glyf::accelerator_t glyf;
+#ifndef HB_NO_SUBSET_CFF
+  OT::cff1::accelerator_t cff;
+#endif
+  OT::COLR::accelerator_t colr;
+  cmap.init (plan->source);
+  glyf.init (plan->source);
+#ifndef HB_NO_SUBSET_CFF
+  cff.init (plan->source);
+#endif
+  colr.init (plan->source);
+
+  plan->_glyphset_gsub->add (0); // Not-def
+  hb_set_union (plan->_glyphset_gsub, input_glyphs_to_retain);
+
+  hb_codepoint_t cp = HB_SET_VALUE_INVALID;
+  while (unicodes->next (&cp))
+  {
+    hb_codepoint_t gid;
+    if (!cmap.get_nominal_glyph (cp, &gid))
+    {
+      DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
+      continue;
+    }
+    plan->unicodes->add (cp);
+    plan->codepoint_to_glyph->set (cp, gid);
+    plan->_glyphset_gsub->add (gid);
+  }
+
+  _cmap_closure (plan->source, plan->unicodes, plan->_glyphset_gsub);
+
+#ifndef HB_NO_SUBSET_LAYOUT
+  if (close_over_gsub)
+    // closure all glyphs/lookups/features needed for GSUB substitutions.
+    _gsub_closure_glyphs_lookups_features (plan->source, plan->_glyphset_gsub, plan->gsub_lookups, plan->gsub_features);
+
+  if (close_over_gpos)
+    _gpos_closure_lookups_features (plan->source, plan->_glyphset_gsub, plan->gpos_lookups, plan->gpos_features);
+#endif
+  _remove_invalid_gids (plan->_glyphset_gsub, plan->source->get_num_glyphs ());
+
+  // Populate a full set of glyphs to retain by adding all referenced
+  // composite glyphs.
+  hb_codepoint_t gid = HB_SET_VALUE_INVALID;
+  while (plan->_glyphset_gsub->next (&gid))
+  {
+    glyf.add_gid_and_children (gid, plan->_glyphset);
+#ifndef HB_NO_SUBSET_CFF
+    if (cff.is_valid ())
+      _add_cff_seac_components (cff, gid, plan->_glyphset);
+#endif
+    if (colr.is_valid ())
+      colr.closure_glyphs (gid, plan->_glyphset);
+  }
+
+  _remove_invalid_gids (plan->_glyphset, plan->source->get_num_glyphs ());
+
+#ifndef HB_NO_VAR
+  if (close_over_gdef)
+    _collect_layout_variation_indices (plan->source, plan->_glyphset, plan->gpos_lookups, plan->layout_variation_indices, plan->layout_variation_idx_map);
+#endif
+
+#ifndef HB_NO_SUBSET_CFF
+  cff.fini ();
+#endif
+  glyf.fini ();
+  cmap.fini ();
+}
+
+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 */)
+{
+  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)
+    ;
+
+    unsigned max_glyph =
+    + hb_iter (all_gids_to_retain)
+    | hb_reduce (hb_max, 0u)
+    ;
+    *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)
+{
+#ifndef HB_NO_STYLE
+  face->table.STAT->collect_name_ids (nameids);
+#endif
+#ifndef HB_NO_VAR
+  face->table.fvar->collect_name_ids (nameids);
+#endif
+}
+
+/**
+ * hb_subset_plan_create:
+ * 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: New subset plan.
+ *
+ * Since: 1.7.5
+ **/
+hb_subset_plan_t *
+hb_subset_plan_create (hb_face_t         *face,
+		       hb_subset_input_t *input)
+{
+  hb_subset_plan_t *plan;
+  if (unlikely (!(plan = hb_object_create<hb_subset_plan_t> ())))
+    return const_cast<hb_subset_plan_t *> (&Null (hb_subset_plan_t));
+
+  plan->successful = true;
+  plan->drop_hints = input->drop_hints;
+  plan->desubroutinize = input->desubroutinize;
+  plan->retain_gids = input->retain_gids;
+  plan->name_legacy = input->name_legacy;
+  plan->unicodes = hb_set_create ();
+  plan->name_ids = hb_set_reference (input->name_ids);
+  _nameid_closure (face, plan->name_ids);
+  plan->name_languages = hb_set_reference (input->name_languages);
+  plan->glyphs_requested = hb_set_reference (input->glyphs);
+  plan->drop_tables = hb_set_reference (input->drop_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->codepoint_to_glyph = hb_map_create ();
+  plan->glyph_map = hb_map_create ();
+  plan->reverse_glyph_map = hb_map_create ();
+  plan->gsub_lookups = hb_map_create ();
+  plan->gpos_lookups = hb_map_create ();
+  plan->gsub_features = hb_map_create ();
+  plan->gpos_features = hb_map_create ();
+  plan->layout_variation_indices = hb_set_create ();
+  plan->layout_variation_idx_map = hb_map_create ();
+
+  _populate_gids_to_retain (plan,
+			    input->unicodes,
+			    input->glyphs,
+			    !input->drop_tables->has (HB_OT_TAG_GSUB),
+			    !input->drop_tables->has (HB_OT_TAG_GPOS),
+			    !input->drop_tables->has (HB_OT_TAG_GDEF));
+
+  _create_old_gid_to_new_gid_map (face,
+				  input->retain_gids,
+				  plan->_glyphset,
+				  plan->glyph_map,
+				  plan->reverse_glyph_map,
+				  &plan->_num_output_glyphs);
+
+  return plan;
+}
+
+/**
+ * hb_subset_plan_destroy:
+ *
+ * Since: 1.7.5
+ **/
+void
+hb_subset_plan_destroy (hb_subset_plan_t *plan)
+{
+  if (!hb_object_destroy (plan)) return;
+
+  hb_set_destroy (plan->unicodes);
+  hb_set_destroy (plan->name_ids);
+  hb_set_destroy (plan->name_languages);
+  hb_set_destroy (plan->glyphs_requested);
+  hb_set_destroy (plan->drop_tables);
+  hb_face_destroy (plan->source);
+  hb_face_destroy (plan->dest);
+  hb_map_destroy (plan->codepoint_to_glyph);
+  hb_map_destroy (plan->glyph_map);
+  hb_map_destroy (plan->reverse_glyph_map);
+  hb_set_destroy (plan->_glyphset);
+  hb_set_destroy (plan->_glyphset_gsub);
+  hb_map_destroy (plan->gsub_lookups);
+  hb_map_destroy (plan->gpos_lookups);
+  hb_map_destroy (plan->gsub_features);
+  hb_map_destroy (plan->gpos_features);
+  hb_set_destroy (plan->layout_variation_indices);
+  hb_map_destroy (plan->layout_variation_idx_map);
+
+
+  free (plan);
+}