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[lazy] More

This commit is contained in:
Behdad Esfahbod 2018-08-12 13:12:29 -07:00
parent 5abdf5eeba
commit 918ad9f5d9
1 changed files with 37 additions and 8 deletions
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45
src/hb-machinery-private.hh
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@ -590,18 +590,51 @@ struct BEInt<Type, 4>
* Lazy loaders.
*/
template <typename Data, unsigned int WheresData>
struct hb_data_wrapper_t
{
static_assert (WheresData > 0, "");
inline Data * get_data (void) const
{
return *(((Data **) this) - WheresData);
}
template <typename Stored, typename Subclass>
inline Stored * call_create (void) const
{
Data *data = this->get_data ();
return likely (data) ? Subclass::create (data) : nullptr;
}
};
template <>
struct hb_data_wrapper_t<void, 0>
{
template <typename Stored, typename Subclass>
inline Stored * call_create (void) const
{
return Subclass::create ();
}
};
template <typename Subclass,
typename Data,
unsigned int WheresData,
typename Returned,
typename Stored = Returned>
struct hb_lazy_loader_t
struct hb_lazy_loader_t : hb_data_wrapper_t<Data, WheresData>
{
static_assert (WheresData > 0, "");
inline void init0 (void) {} /* Init, when memory is already set to 0. No-op for us. */
inline void init (void) { instance.set_relaxed (nullptr); }
inline void fini (void) { destroy (instance.get ()); }
inline Stored * create (void) const
{
Stored *p = this->template call_create<Stored, Subclass> ();
if (unlikely (!p))
p = const_cast<Stored *> (Subclass::get_null ());
return p;
}
static inline void destroy (Stored *p)
{
if (p && p != Subclass::get_null ())
@ -622,11 +655,7 @@ struct hb_lazy_loader_t
Stored *p = this->instance.get ();
if (unlikely (!p))
{
Data *data = get_data ();
if (likely (data))
p = Subclass::create (data);
if (unlikely (!p))
p = const_cast<Stored *> (Subclass::get_null ());
p = create ();
assert (p);
if (unlikely (!this->instance.cmpexch (nullptr, p)))
{