From 271d59feaee8770a54a77967417d58ccca163060 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Fri, 10 Jul 2015 11:09:09 +0200
Subject: YYY kern: implement queue_replace

* kern/queue.h (queue_replace): New macro.
---
 kern/queue.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kern/queue.h b/kern/queue.h
index f0b4002..0080e78 100644
--- a/kern/queue.h
+++ b/kern/queue.h
@@ -320,6 +320,21 @@ void		insque(queue_entry_t, queue_entry_t);
 	(head)->prev = prev;					\
 }
 
+/*
+ *	Macro:		queue_replace
+ */
+#define	queue_replace(head, to, from, type, field)			\
+	{								\
+	if ((head) == (from)->field.prev)				\
+		(head)->next = (to);					\
+	else								\
+		((type)((from)->field.prev))->field.next = (to);	\
+	if ((head) == (from)->field.next)				\
+		(head)->prev = (to);					\
+	else								\
+		((type)((from)->field.next))->field.prev = (to);	\
+}
+
 /*
  *	Macro:		queue_assign
  */
-- 
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