Add atomic-pointer functions
Gonig to use these for lock-free linked-lists, to be used for
hb_language_t among other things.
diff --git a/src/hb-atomic-private.hh b/src/hb-atomic-private.hh
index 3394afc..c1b25bd 100644
--- a/src/hb-atomic-private.hh
+++ b/src/hb-atomic-private.hh
@@ -45,22 +45,34 @@
#elif !defined(HB_NO_MT) && defined(_MSC_VER) && _MSC_VER >= 1600
#include <intrin.h>
+#pragma intrinsic(_InterlockedExchangeAdd, _InterlockedCompareExchangePointer)
+
typedef long hb_atomic_int_t;
#define hb_atomic_int_add(AI, V) _InterlockedExchangeAdd (&(AI), (V))
+#define hb_atomic_ptr_get(P) (MemoryBarrier (), (void *) *(P))
+#define hb_atomic_ptr_cmpexch(P,O,N) (_InterlockedCompareExchangePointer ((void * volatile *) (P), (N), (O)) == (O))
+
#elif !defined(HB_NO_MT) && defined(__APPLE__)
#include <libkern/OSAtomic.h>
+
typedef int32_t hb_atomic_int_t;
#define hb_atomic_int_add(AI, V) (OSAtomicAdd32Barrier ((V), &(AI)) - (V))
+#define hb_atomic_ptr_get(P) (OSMemoryBarrier (), (void *) *(P))
+#define hb_atomic_ptr_cmpexch(P,O,N) OSAtomicCompareAndSwapPtrBarrier ((O), (N), (void * volatile *) (P))
+
#elif !defined(HB_NO_MT) && defined(__GNUC__)
typedef int hb_atomic_int_t;
#define hb_atomic_int_add(AI, V) __sync_fetch_and_add (&(AI), (V))
+#define hb_atomic_ptr_get(P) (void *) (__sync_synchronize (), *(P))
+#define hb_atomic_ptr_cmpexch(P,O,N) __sync_bool_compare_and_swap ((P), (O), (N))
+
#elif !defined(HB_NO_MT) && defined(HAVE_GLIB)
#include <glib.h>
@@ -71,6 +83,9 @@
#define hb_atomic_int_add(AI, V) g_atomic_int_exchange_and_add (&(AI), (V))
#endif
+#define hb_atomic_ptr_get(P) g_atomic_pointer_get (P)
+#define hb_atomic_ptr_cmpexch(P,O,N) g_atomic_pointer_compare_and_exchange ((void * volatile *) (P), (O), (N))
+
#elif !defined(HB_NO_MT)
@@ -78,12 +93,18 @@
typedef volatile int hb_atomic_int_t;
#define hb_atomic_int_add(AI, V) (((AI) += (V)) - (V))
+#define hb_atomic_ptr_get(P) ((void *) *(P))
+#define hb_atomic_ptr_cmpexch(P,O,N) (*(P) == (O) ? (*(P) = (N), TRUE) : FALSE)
+
#else /* HB_NO_MT */
typedef int hb_atomic_int_t;
#define hb_atomic_int_add(AI, V) (((AI) += (V)) - (V))
+#define hb_atomic_ptr_get(P) ((void *) *(P))
+#define hb_atomic_ptr_cmpexch(P,O,N) *(P)
+
#endif
/* TODO Add tracing. */
