From 7194c2a2a370a39d8e41539cb7fde9a9ffed80c3 Mon Sep 17 00:00:00 2001
From: Garret Rieger <grieger@google.com>
Date: Fri, 27 Aug 2021 08:20:58 -0700
Subject: [PATCH] [subset] use anonymous union to hold the input sets instead
 of a map.

---
 src/hb-subset-input.cc | 16 +++---------
 src/hb-subset-input.hh | 56 ++++++++++++++++++++++++++++--------------
 2 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/src/hb-subset-input.cc b/src/hb-subset-input.cc
index b70c86a5b..c2b7c0492 100644
--- a/src/hb-subset-input.cc
+++ b/src/hb-subset-input.cc
@@ -45,14 +45,8 @@ hb_subset_input_create_or_fail (void)
   if (unlikely (!input))
     return nullptr;
 
-  input->sets.init ();
-  input->sets.set (HB_SUBSET_SETS_GLYPH_INDEX, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_UNICODE, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_NO_SUBSET_TABLE_TAG, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_DROP_TABLE_TAG, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_NAME_ID, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_NAME_LANG_ID, hb_set_create ());
-  input->sets.set (HB_SUBSET_SETS_LAYOUT_FEATURE_TAG, hb_set_create ());
+  for (auto& set : input->sets_iter ())
+    set = hb_set_create ();
 
   if (input->in_error ())
   {
@@ -234,11 +228,9 @@ hb_subset_input_destroy (hb_subset_input_t *input)
 {
   if (!hb_object_destroy (input)) return;
 
-  for (hb_set_t* set : input->sets.values ())
+  for (hb_set_t* set : input->sets_iter ())
     hb_set_destroy (set);
 
-  input->sets.fini ();
-
   hb_free (input);
 }
 
@@ -361,7 +353,7 @@ HB_EXTERN hb_set_t *
 hb_subset_input_set (hb_subset_input_t *input, hb_subset_sets_t set_type)
 {
   // TODO(garretrieger): add test for this method.
-  return input->sets.get (set_type);
+  return input->sets_iter () [set_type];
 }
 
 /**
diff --git a/src/hb-subset-input.hh b/src/hb-subset-input.hh
index 82ffb6d73..0b0609128 100644
--- a/src/hb-subset-input.hh
+++ b/src/hb-subset-input.hh
@@ -42,86 +42,106 @@ struct hb_subset_input_t
 {
   hb_object_header_t header;
 
-  hb_hashmap_t<unsigned, hb_set_t*> sets;
+  union {
+    struct {
+      hb_set_t *glyphs;
+      hb_set_t *unicodes;
+      hb_set_t *no_subset_tables;
+      hb_set_t *drop_tables;
+      hb_set_t *name_ids;
+      hb_set_t *name_languages;
+      hb_set_t *layout_features;
+    } sets;
+    hb_set_t* set_ptrs[1];
+  };
 
   unsigned flags;
 
+  inline unsigned num_sets () const
+  {
+    return sizeof (sets) / sizeof (hb_set_t*);
+  }
+
+  inline hb_array_t<hb_set_t*> sets_iter ()
+  {
+    return hb_array_t<hb_set_t*> (set_ptrs, num_sets ());
+  }
+
   inline hb_set_t* unicodes()
   {
-    return sets.get (HB_SUBSET_SETS_UNICODE);
+    return sets.unicodes;
   }
 
   inline const hb_set_t* unicodes() const
   {
-    return sets.get (HB_SUBSET_SETS_UNICODE);
+    return sets.unicodes;
   }
 
   inline hb_set_t* glyphs ()
   {
-    return sets.get (HB_SUBSET_SETS_GLYPH_INDEX);
+    return sets.glyphs;
   }
 
   inline const hb_set_t* glyphs () const
   {
-    return sets.get (HB_SUBSET_SETS_GLYPH_INDEX);
+    return sets.glyphs;
   }
 
   inline hb_set_t* name_ids ()
   {
-    return sets.get (HB_SUBSET_SETS_NAME_ID);
+    return sets.name_ids;
   }
 
   inline const hb_set_t* name_ids () const
   {
-    return sets.get (HB_SUBSET_SETS_NAME_ID);
+    return sets.name_ids;
   }
 
   inline hb_set_t* name_languages ()
   {
-    return sets.get (HB_SUBSET_SETS_NAME_LANG_ID);
+    return sets.name_languages;
   }
 
   inline const hb_set_t* name_languages () const
   {
-    return sets.get (HB_SUBSET_SETS_NAME_LANG_ID);
+    return sets.name_languages;
   }
 
   inline hb_set_t* no_subset_tables ()
   {
-    return sets.get (HB_SUBSET_SETS_NO_SUBSET_TABLE_TAG);
+    return sets.no_subset_tables;
   }
 
   inline const hb_set_t* no_subset_tables () const
   {
-    return sets.get (HB_SUBSET_SETS_NO_SUBSET_TABLE_TAG);
+    return sets.no_subset_tables;
   }
 
   inline hb_set_t* drop_tables ()
   {
-    return sets.get (HB_SUBSET_SETS_DROP_TABLE_TAG);
+    return sets.drop_tables;
   }
 
   inline const hb_set_t* drop_tables () const
   {
-    return sets.get (HB_SUBSET_SETS_DROP_TABLE_TAG);
+    return sets.drop_tables;
   }
 
   inline hb_set_t* layout_features ()
   {
-    return sets.get (HB_SUBSET_SETS_LAYOUT_FEATURE_TAG);
+    return sets.layout_features;
   }
 
   inline const hb_set_t* layout_features () const
   {
-    return sets.get (HB_SUBSET_SETS_LAYOUT_FEATURE_TAG);
+    return sets.layout_features;
   }
 
   bool in_error () const
   {
-    if (sets.in_error ()) return true;
-    for (const hb_set_t* set : sets.values ())
+    for (unsigned i = 0; i < num_sets (); i++)
     {
-      if (unlikely (set->in_error ()))
+      if (unlikely (set_ptrs[i]->in_error ()))
         return true;
     }
     return false;