[bit-set-invertible] Implement get_min/max

src/hb-bit-set-invertible.hh

@@ -146,9 +146,9 @@ struct hb_bit_set_invertible_t
   { return inverted ? INVALID - s.get_population () : s.get_population (); }
 
   hb_codepoint_t get_min () const
-  { return /*XXX(inverted)*/s.get_min (); }
+  { return s.get_min (inverted); }
   hb_codepoint_t get_max () const
-  { return /*XXX(inverted)*/s.get_max (); }
+  { return inverted ? /*XXX*/ INVALID - 1 : s.get_max (); }
 
   static constexpr hb_codepoint_t INVALID = hb_bit_set_t::INVALID;
 

src/hb-bit-set.hh

@@ -711,16 +711,26 @@ struct hb_bit_set_t
     population = pop;
     return pop;
   }
-  hb_codepoint_t get_min () const
+  hb_codepoint_t get_min (bool inverted = false) const
   {
+    unsigned last_major = (unsigned) -1;
+
     unsigned count = pages.length;
     for (unsigned i = 0; i < count; i++)
     {
       const auto& map = page_map[i];
       const auto& page = pages[map.index];
 
-      if (!page.is_empty ())
-	return map.major * page_t::PAGE_BITS + page.get_min ();
+      if (inverted)
+      {
+        if (last_major + 1 != map.major)
+	  return (last_major + 1) * page_t::PAGE_BITS;
+
+	last_major = map.major;
+      }
+
+      if (!page.is_empty (inverted))
+	return map.major * page_t::PAGE_BITS + page.get_min (inverted);
     }
     return INVALID;
   }