Allocate user-data-array on the heap
This saves each object allocation 72 bytes. Now object overhead is just
16 bytes (on x86) instead of 88 bytes. Neat.
diff --git a/src/hb-object-private.hh b/src/hb-object-private.hh
index 75a72f4..1f61dce 100644
--- a/src/hb-object-private.hh
+++ b/src/hb-object-private.hh
@@ -62,7 +62,6 @@
/* user_data */
-#define HB_USER_DATA_ARRAY_INIT {HB_MUTEX_INIT, HB_LOCKABLE_SET_INIT}
struct hb_user_data_array_t
{
struct hb_user_data_item_t {
@@ -97,9 +96,9 @@
struct hb_object_header_t
{
hb_reference_count_t ref_count;
- hb_user_data_array_t user_data;
+ hb_user_data_array_t *user_data;
-#define HB_OBJECT_HEADER_STATIC {HB_REFERENCE_COUNT_INIT, HB_USER_DATA_ARRAY_INIT}
+#define HB_OBJECT_HEADER_STATIC {HB_REFERENCE_COUNT_INIT, nullptr}
private:
ASSERT_POD ();
@@ -133,7 +132,7 @@
static inline void hb_object_init (Type *obj)
{
obj->header.ref_count.init (1);
- obj->header.user_data.init ();
+ obj->header.user_data = nullptr;
}
template <typename Type>
static inline bool hb_object_is_inert (const Type *obj)
@@ -172,7 +171,11 @@
static inline void hb_object_fini (Type *obj)
{
obj->header.ref_count.fini (); /* Do this before user_data */
- obj->header.user_data.fini ();
+ if (obj->header.user_data)
+ {
+ obj->header.user_data->fini ();
+ free (obj->header.user_data);
+ }
}
template <typename Type>
static inline bool hb_object_set_user_data (Type *obj,
@@ -184,17 +187,34 @@
if (unlikely (!obj || hb_object_is_inert (obj)))
return false;
assert (hb_object_is_valid (obj));
- return obj->header.user_data.set (key, data, destroy, replace);
+
+retry:
+ hb_user_data_array_t *user_data = (hb_user_data_array_t *) hb_atomic_ptr_get (&obj->header.user_data);
+ if (unlikely (!user_data))
+ {
+ user_data = (hb_user_data_array_t *) calloc (sizeof (hb_user_data_array_t), 1);
+ if (unlikely (!user_data))
+ return false;
+ user_data->init ();
+ if (unlikely (!hb_atomic_ptr_cmpexch (&obj->header.user_data, nullptr, user_data)))
+ {
+ user_data->fini ();
+ free (user_data);
+ goto retry;
+ }
+ }
+
+ return user_data->set (key, data, destroy, replace);
}
template <typename Type>
static inline void *hb_object_get_user_data (Type *obj,
hb_user_data_key_t *key)
{
- if (unlikely (!obj || hb_object_is_inert (obj)))
+ if (unlikely (!obj || hb_object_is_inert (obj) || !obj->header.user_data))
return nullptr;
assert (hb_object_is_valid (obj));
- return obj->header.user_data.get (key);
+ return obj->header.user_data->get (key);
}