LGPL

[vlc] / src / misc / atomic.c

diff --git a/src/misc/atomic.c b/src/misc/atomic.c
index 1f97f599e1578ed0811484ebe3158023a1beab11..f79a49133adfa14af464254bb3e11addaa1aa68f 100644 (file)
--- a/src/misc/atomic.c
+++ b/src/misc/atomic.c
@@ -3,19 +3,19 @@
  *****************************************************************************
  * Copyright (C) 2010 Rémi Denis-Courmont
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  *****************************************************************************/
 
 #ifdef HAVE_CONFIG_H
@@ -46,6 +46,24 @@ uintptr_t vlc_atomic_add (vlc_atomic_t *atom, uintptr_t v)
     return __sync_add_and_fetch (&atom->u, v);
 }
 
+uintptr_t vlc_atomic_swap (vlc_atomic_t *atom, uintptr_t v)
+{
+    /* grmbl, gcc does not provide an intrinsic for this! */
+    uintptr_t u;
+
+    do
+        u = vlc_atomic_get (atom);
+    while (vlc_atomic_compare_swap (atom, u, v) != u);
+
+    return u;
+}
+
+uintptr_t vlc_atomic_compare_swap (vlc_atomic_t *atom,
+                                   uintptr_t oldval, uintptr_t newval)
+{
+    return __sync_val_compare_and_swap (&atom->u, oldval, newval);
+}
+
 #else
 /* Worst-case fallback implementation with a mutex */
 
@@ -78,4 +96,30 @@ uintptr_t vlc_atomic_add (vlc_atomic_t *atom, uintptr_t v)
     return v;
 }
 
+uintptr_t vlc_atomic_swap (vlc_atomic_t *atom, uintptr_t v)
+{
+    uintptr_t u;
+
+    vlc_mutex_lock (&lock);
+    u = atom->u;
+    atom->u = v;
+    vlc_mutex_unlock (&lock);
+
+    return u;
+}
+
+uintptr_t vlc_atomic_compare_swap (vlc_atomic_t *atom,
+                                       uintptr_t oldval, uintptr_t newval)
+{
+    uintptr_t u;
+
+    vlc_mutex_lock (&lock);
+    u = atom->u;
+    if (u == oldval)
+        atom->u = newval;
+    vlc_mutex_unlock (&lock);
+
+    return u;
+}
+
 #endif