Moving the net kit private includes files to /current tree.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@897 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/net/lock.h

@@ -0,0 +1,128 @@
+#ifndef LOCK_H
+#define LOCK_H
+/* lock.h - benaphore locking, "faster semaphores", read/write locks
+**		sorry for all those macros; I wish C would support C++-style
+**		inline functions.
+**
+** Initial version by Axel Dörfler, [email protected]
+**
+** This file may be used under the terms of the OpenBeOS License.
+*/
+
+
+#include <SupportDefs.h>
+
+// for read/write locks
+#define MAX_READERS 100000
+
+
+struct benaphore {
+	sem_id	sem;
+	int32	count;
+};
+
+typedef struct benaphore benaphore;
+
+// it may make sense to add a status field to the rw_lock to
+// be able to check if the semaphore could be locked
+
+struct rw_lock {
+	sem_id		sem;
+	int32		count;
+	benaphore	writeLock;
+};
+
+typedef struct rw_lock rw_lock;
+
+#ifndef _KERNEL_
+#define INIT_BENAPHORE(lock,name) \
+	{ \
+		(lock).count = 1; \
+		(lock).sem = create_sem(0, name); \
+	}
+
+#else
+
+#define INIT_BENAPHORE(lock,name) \
+        { \
+                (lock).count = 1; \
+                (lock).sem = create_sem(0, name); \
+                set_sem_owner((lock).sem, B_SYSTEM_TEAM); \
+        }
+#endif
+
+
+#define CHECK_BENAPHORE(lock) \
+	((lock).sem)
+
+#define UNINIT_BENAPHORE(lock) \
+	delete_sem((lock).sem);
+
+#define ACQUIRE_BENAPHORE(lock) \
+	(atomic_add(&((lock).count), -1) <= 0 ? \
+		acquire_sem_etc((lock).sem, 1, B_CAN_INTERRUPT, 0) \
+		: B_OK)
+
+#define RELEASE_BENAPHORE(lock) \
+	{ \
+		if (atomic_add(&((lock).count), 1) < 0) \
+			release_sem((lock).sem); \
+	}
+
+/* read/write lock */
+#ifndef _KERNEL_
+#define INIT_RW_LOCK(lock,name) \
+	{ \
+		(lock).sem = create_sem(0, name); \
+		(lock).count = MAX_READERS; \
+		INIT_BENAPHORE((lock).writeLock, "r/w write lock"); \
+	}
+
+#else
+
+#define INIT_RW_LOCK(lock,name) \
+        { \
+                (lock).sem = create_sem(0, name); \
+                set_sem_owner((lock).sem, B_SYSTEM_TEAM); \
+                (lock).count = MAX_READERS; \
+                INIT_BENAPHORE((lock).writeLock, "r/w write lock"); \
+        }
+
+#endif
+#define CHECK_RW_LOCK(lock) \
+	((lock).sem)
+
+#define UNINIT_RW_LOCK(lock) \
+	delete_sem((lock).sem); \
+	UNINIT_BENAPHORE((lock).writeLock)
+
+#define ACQUIRE_READ_LOCK(lock) \
+	{ \
+		if (atomic_add(&(lock).count, -1) <= 0) \
+			acquire_sem((lock).sem); \
+	}
+
+#define RELEASE_READ_LOCK(lock) \
+	{ \
+		if (atomic_add(&(lock).count, 1) < 0) \
+			release_sem((lock).sem); \
+	}
+
+#define ACQUIRE_WRITE_LOCK(lock) \
+	{ \
+		int32 readers; \
+		ACQUIRE_BENAPHORE((lock).writeLock); \
+		readers = atomic_add(&(lock).count, -MAX_READERS); \
+		if (readers < MAX_READERS) \
+			acquire_sem_etc((lock).sem,readers <= 0 ? 1 : MAX_READERS - readers,0,0); \
+		RELEASE_BENAPHORE((lock).writeLock); \
+	}
+
+#define RELEASE_WRITE_LOCK(lock) \
+	{ \
+		int32 readers = atomic_add(&(lock).count,MAX_READERS); \
+		if (readers < 0) \
+			release_sem_etc((lock).sem,readers <= -MAX_READERS ? 1 : -readers,B_CAN_INTERRUPT); \
+	}
+
+#endif	/* LOCK_H */