[object] Simplify reference_count_t

src/hb-object.hh

@@ -140,9 +140,7 @@ struct hb_lockable_set_t
  * Reference-count.
  */
 
-#define HB_REFERENCE_COUNT_INERT_VALUE 0
-#define HB_REFERENCE_COUNT_POISON_VALUE -0x0000DEAD
-#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT (HB_REFERENCE_COUNT_INERT_VALUE)}
+#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT (0)}
 
 struct hb_reference_count_t
 {
@@ -152,9 +150,9 @@ struct hb_reference_count_t
   int get_relaxed () const { return ref_count.get_relaxed (); }
   int inc () const { return ref_count.inc (); }
   int dec () const { return ref_count.dec (); }
-  void fini () { ref_count.set_relaxed (HB_REFERENCE_COUNT_POISON_VALUE); }
+  void fini () { ref_count.set_relaxed (-0x0000DEAD); }
 
-  bool is_inert () const { return ref_count.get_relaxed () == HB_REFERENCE_COUNT_INERT_VALUE; }
+  bool is_inert () const { return !ref_count.get_relaxed (); }
   bool is_valid () const { return ref_count.get_relaxed () > 0; }
 };