Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/src/util/ring.h b/src/util/ring.h
new file mode 100644
index 0000000..47749e2
--- /dev/null
+++ b/src/util/ring.h
@@ -0,0 +1,59 @@
+#ifndef _RING_H_INCLUDED_
+#define _RING_H_INCLUDED_
+
+/*++
+/* NAME
+/*	ring 3h
+/* SUMMARY
+/*	circular list management
+/* SYNOPSIS
+/*	#include <ring.h>
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * External interface.
+  */
+typedef struct RING RING;
+
+struct RING {
+    RING   *succ;			/* successor */
+    RING   *pred;			/* predecessor */
+};
+
+extern void ring_init(RING *);
+extern void ring_prepend(RING *, RING *);
+extern void ring_append(RING *, RING *);
+extern void ring_detach(RING *);
+
+#define ring_succ(c) ((c)->succ)
+#define ring_pred(c) ((c)->pred)
+
+#define RING_FOREACH(entry, head) \
+    for (entry = ring_succ(head); entry != (head); entry = ring_succ(entry))
+
+ /*
+  * Typically, an application will embed a RING structure into a larger
+  * structure that also contains application-specific members. This approach
+  * gives us the best of both worlds. The application can still use the
+  * generic RING primitives for manipulating RING structures. The macro below
+  * transforms a pointer from RING structure to the structure that contains
+  * it.
+  */
+#define RING_TO_APPL(ring_ptr,app_type,ring_member) \
+    ((app_type *) (((char *) (ring_ptr)) - offsetof(app_type,ring_member)))
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/* LAST MODIFICATION
+/*	Tue Jan 28 16:50:20 EST 1997
+/*--*/
+
+#endif