Added wrapper for POSIX spin locks

src/libstrongswan/threading/spinlock.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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 (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup spinlock spinlock
+ * @{ @ingroup threading
+ */
+
+#ifndef THREADING_SPINLOCK_H_
+#define THREADING_SPINLOCK_H_
+
+typedef struct spinlock_t spinlock_t;
+
+/**
+ * Spin lock wrapper implements a lock with low overhead when the lock is held
+ * only for a short time (waiting wastes processor cycles, though).
+ *
+ * If native spin locks are not available regular mutexes are used as fallback.
+ */
+struct spinlock_t {
+
+	/**
+	 * Acquire the lock.
+	 */
+	void (*lock)(spinlock_t *this);
+
+	/**
+	 * Release the lock.
+	 */
+	void (*unlock)(spinlock_t *this);
+
+	/**
+	 * Destroy the instance.
+	 */
+	void (*destroy)(spinlock_t *this);
+};
+
+/**
+ * Create a spin lock instance.
+ *
+ * @return			unlocked instance
+ */
+spinlock_t *spinlock_create();
+
+#endif /** THREADING_SPINLOCK_H_ @} */
+