diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index ee0796e31..4b9afb7e1 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -613,7 +613,7 @@ hb_ot_shape_glyphs_closure (hb_font_t          *font,
   do {
     copy.set (glyphs);
     HB_SHAPER_DATA_GET (shape_plan)->substitute_closure (font->face, glyphs);
-  } while (!copy.equal (glyphs));
+  } while (!copy.is_equal (glyphs));
 
   hb_shape_plan_destroy (shape_plan);
 }
diff --git a/src/hb-set-private.hh b/src/hb-set-private.hh
index 43cf925bf..c736b6993 100644
--- a/src/hb-set-private.hh
+++ b/src/hb-set-private.hh
@@ -147,7 +147,7 @@ struct hb_set_t
   inline void clear (void) {
     memset (elts, 0, sizeof elts);
   }
-  inline bool empty (void) const {
+  inline bool is_empty (void) const {
     for (unsigned int i = 0; i < ARRAY_LENGTH (elts); i++)
       if (elts[i])
         return false;
@@ -161,6 +161,7 @@ struct hb_set_t
   }
   inline void add_range (hb_codepoint_t a, hb_codepoint_t b)
   {
+    /* TODO Speedup */
     for (unsigned int i = a; i < b + 1; i++)
       add (i);
   }
@@ -169,6 +170,12 @@ struct hb_set_t
     if (unlikely (g > MAX_G)) return;
     elt (g) &= ~mask (g);
   }
+  inline void del_range (hb_codepoint_t a, hb_codepoint_t b)
+  {
+    /* TODO Speedup */
+    for (unsigned int i = a; i < b + 1; i++)
+      del (i);
+  }
   inline bool has (hb_codepoint_t g) const
   {
     if (unlikely (g > MAX_G)) return false;
@@ -185,7 +192,7 @@ struct hb_set_t
         return true;
     return false;
   }
-  inline bool equal (const hb_set_t *other) const
+  inline bool is_equal (const hb_set_t *other) const
   {
     for (unsigned int i = 0; i < ELTS; i++)
       if (elts[i] != other->elts[i])
@@ -217,7 +224,7 @@ struct hb_set_t
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] ^= other->elts[i];
   }
-  inline bool next (hb_codepoint_t *codepoint)
+  inline bool next (hb_codepoint_t *codepoint) const
   {
     if (unlikely (*codepoint == SENTINEL)) {
       hb_codepoint_t i = get_min ();
@@ -234,6 +241,28 @@ struct hb_set_t
       }
     return false;
   }
+  inline bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const
+  {
+    hb_codepoint_t i;
+
+    i = *last;
+    if (!next (&i))
+      return false;
+
+    *last = *first = i;
+    while (next (&i) && i == *last + 1)
+      (*last)++;
+
+    return true;
+  }
+
+  inline unsigned int get_population (void) const
+  {
+    unsigned int count = 0;
+    for (unsigned int i = 0; i < ELTS; i++)
+      count += _hb_popcount32 (elts[i]);
+    return count;
+  }
   inline hb_codepoint_t get_min (void) const
   {
     for (unsigned int i = 0; i < ELTS; i++)
diff --git a/src/hb-set.cc b/src/hb-set.cc
index 4225e3c98..37866c40a 100644
--- a/src/hb-set.cc
+++ b/src/hb-set.cc
@@ -32,7 +32,7 @@
 
 
 hb_set_t *
-hb_set_create ()
+hb_set_create (void)
 {
   hb_set_t *set;
 
@@ -73,25 +73,25 @@ hb_set_destroy (hb_set_t *set)
 }
 
 hb_bool_t
-hb_set_set_user_data (hb_set_t        *set,
-			 hb_user_data_key_t *key,
-			 void *              data,
-			 hb_destroy_func_t   destroy,
-			 hb_bool_t           replace)
+hb_set_set_user_data (hb_set_t           *set,
+		      hb_user_data_key_t *key,
+		      void *              data,
+		      hb_destroy_func_t   destroy,
+		      hb_bool_t           replace)
 {
   return hb_object_set_user_data (set, key, data, destroy, replace);
 }
 
 void *
-hb_set_get_user_data (hb_set_t        *set,
-			 hb_user_data_key_t *key)
+hb_set_get_user_data (hb_set_t           *set,
+		      hb_user_data_key_t *key)
 {
   return hb_object_get_user_data (set, key);
 }
 
 
 hb_bool_t
-hb_set_allocation_successful (hb_set_t  *set HB_UNUSED)
+hb_set_allocation_successful (const hb_set_t  *set HB_UNUSED)
 {
   return true;
 }
@@ -103,13 +103,13 @@ hb_set_clear (hb_set_t *set)
 }
 
 hb_bool_t
-hb_set_empty (hb_set_t *set)
+hb_set_is_empty (const hb_set_t *set)
 {
-  return set->empty ();
+  return set->is_empty ();
 }
 
 hb_bool_t
-hb_set_has (hb_set_t       *set,
+hb_set_has (const hb_set_t *set,
 	    hb_codepoint_t  codepoint)
 {
   return set->has (codepoint);
@@ -122,6 +122,14 @@ hb_set_add (hb_set_t       *set,
   set->add (codepoint);
 }
 
+void
+hb_set_add_range (hb_set_t       *set,
+		  hb_codepoint_t  first,
+		  hb_codepoint_t  last)
+{
+  set->add_range (first, last);
+}
+
 void
 hb_set_del (hb_set_t       *set,
 	    hb_codepoint_t  codepoint)
@@ -129,63 +137,85 @@ hb_set_del (hb_set_t       *set,
   set->del (codepoint);
 }
 
-hb_bool_t
-hb_set_equal (hb_set_t *set,
-	      hb_set_t *other)
+void
+hb_set_del_range (hb_set_t       *set,
+		  hb_codepoint_t  first,
+		  hb_codepoint_t  last)
 {
-  return set->equal (other);
+  set->del_range (first, last);
+}
+
+hb_bool_t
+hb_set_is_equal (const hb_set_t *set,
+		 const hb_set_t *other)
+{
+  return set->is_equal (other);
 }
 
 void
-hb_set_set (hb_set_t *set,
-	    hb_set_t *other)
+hb_set_set (hb_set_t       *set,
+	    const hb_set_t *other)
 {
   set->set (other);
 }
 
 void
-hb_set_union (hb_set_t *set,
-	      hb_set_t *other)
+hb_set_union (hb_set_t       *set,
+	      const hb_set_t *other)
 {
   set->union_ (other);
 }
 
 void
-hb_set_intersect (hb_set_t *set,
-		  hb_set_t *other)
+hb_set_intersect (hb_set_t       *set,
+		  const hb_set_t *other)
 {
   set->intersect (other);
 }
 
 void
-hb_set_subtract (hb_set_t *set,
-		 hb_set_t *other)
+hb_set_subtract (hb_set_t       *set,
+		 const hb_set_t *other)
 {
   set->subtract (other);
 }
 
 void
-hb_set_symmetric_difference (hb_set_t *set,
-			     hb_set_t *other)
+hb_set_symmetric_difference (hb_set_t       *set,
+			     const hb_set_t *other)
 {
   set->symmetric_difference (other);
 }
 
+unsigned int
+hb_set_population (const hb_set_t *set)
+{
+  return set->get_population ();
+}
+
 hb_codepoint_t
-hb_set_min (hb_set_t *set)
+hb_set_get_min (const hb_set_t *set)
 {
   return set->get_min ();
 }
 
 hb_codepoint_t
-hb_set_max (hb_set_t *set)
+hb_set_get_max (const hb_set_t *set)
 {
   return set->get_max ();
 }
 
 hb_bool_t
-hb_set_next (hb_set_t       *set,
+hb_set_next (const hb_set_t *set,
 	     hb_codepoint_t *codepoint)
 {
   return set->next (codepoint);
 }
+
+hb_bool_t
+hb_set_next_range (const hb_set_t *set,
+		   hb_codepoint_t *first,
+		   hb_codepoint_t *last)
+{
+  return set->next_range (first, last);
+}
diff --git a/src/hb-set.h b/src/hb-set.h
index 1838889f2..06f358272 100644
--- a/src/hb-set.h
+++ b/src/hb-set.h
@@ -65,16 +65,16 @@ hb_set_get_user_data (hb_set_t           *set,
 
 /* Returns false if allocation has failed before */
 hb_bool_t
-hb_set_allocation_successful (hb_set_t  *set);
+hb_set_allocation_successful (const hb_set_t *set);
 
 void
 hb_set_clear (hb_set_t *set);
 
 hb_bool_t
-hb_set_empty (hb_set_t *set);
+hb_set_is_empty (const hb_set_t *set);
 
 hb_bool_t
-hb_set_has (hb_set_t       *set,
+hb_set_has (const hb_set_t *set,
 	    hb_codepoint_t  codepoint);
 
 /* Right now limited to 16-bit integers.  Eventually will do full codepoint range, sans -1
@@ -83,48 +83,65 @@ void
 hb_set_add (hb_set_t       *set,
 	    hb_codepoint_t  codepoint);
 
+void
+hb_set_add_range (hb_set_t       *set,
+		  hb_codepoint_t  first,
+		  hb_codepoint_t  last);
+
 void
 hb_set_del (hb_set_t       *set,
 	    hb_codepoint_t  codepoint);
 
+void
+hb_set_del_range (hb_set_t       *set,
+		  hb_codepoint_t  first,
+		  hb_codepoint_t  last);
+
 hb_bool_t
-hb_set_equal (hb_set_t *set,
-	      hb_set_t *other);
+hb_set_is_equal (const hb_set_t *set,
+		 const hb_set_t *other);
 
 void
-hb_set_set (hb_set_t *set,
-	    hb_set_t *other);
+hb_set_set (hb_set_t       *set,
+	    const hb_set_t *other);
 
 void
-hb_set_union (hb_set_t *set,
-	      hb_set_t *other);
+hb_set_union (hb_set_t       *set,
+	      const hb_set_t *other);
 
 void
-hb_set_intersect (hb_set_t *set,
-		  hb_set_t *other);
+hb_set_intersect (hb_set_t       *set,
+		  const hb_set_t *other);
 
 void
-hb_set_subtract (hb_set_t *set,
-		 hb_set_t *other);
+hb_set_subtract (hb_set_t       *set,
+		 const hb_set_t *other);
 
 void
-hb_set_symmetric_difference (hb_set_t *set,
-			     hb_set_t *other);
+hb_set_symmetric_difference (hb_set_t       *set,
+			     const hb_set_t *other);
+
+unsigned int
+hb_set_population (const hb_set_t *set);
 
 /* Returns -1 if set empty. */
 hb_codepoint_t
-hb_set_min (hb_set_t *set);
+hb_set_get_min (const hb_set_t *set);
 
 /* Returns -1 if set empty. */
 hb_codepoint_t
-hb_set_max (hb_set_t *set);
+hb_set_get_max (const hb_set_t *set);
 
 /* Pass -1 in to get started. */
 hb_bool_t
-hb_set_next (hb_set_t       *set,
+hb_set_next (const hb_set_t *set,
 	     hb_codepoint_t *codepoint);
 
-/* TODO: Add faster iteration API? */
+/* Pass -1 for first and last to get started. */
+hb_bool_t
+hb_set_next_range (const hb_set_t *set,
+		   hb_codepoint_t *first,
+		   hb_codepoint_t *last);
 
 
 HB_END_DECLS
diff --git a/util/hb-ot-shape-closure.cc b/util/hb-ot-shape-closure.cc
index 2289605cd..41517f232 100644
--- a/util/hb-ot-shape-closure.cc
+++ b/util/hb-ot-shape-closure.cc
@@ -68,7 +68,7 @@ struct shape_closure_consumer_t : option_group_t
     hb_set_clear (glyphs);
     shaper.shape_closure (text, text_len, font, buffer, glyphs);
 
-    if (hb_set_empty (glyphs))
+    if (hb_set_is_empty (glyphs))
       return;
 
     /* Print it out! */