X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=list.h;h=e4b5a1f67b066b73d2a89e0b2e9a7cd6eac00a66;hp=de04ab9eed1184451f5338b06a7a2be9106aac5d;hb=d0d27cfa56d05eaa0e5567c75adfe606eab2957e;hpb=c6d61cae8b5f71ae658dc254c6ee38a14f34dae2

diff --git a/list.h b/list.h
index de04ab9e..e4b5a1f6 100644
--- a/list.h
+++ b/list.h
@@ -33,6 +33,10 @@ struct list_head {
 	struct list_head *prev;
 };
 
+/** Define an initialized list head. */
+#define INITIALIZED_LIST_HEAD(name) struct list_head name = { &(name), &(name) }
+
+
 /** must be called before using any other list functions */
 #define INIT_LIST_HEAD(ptr) do { \
 	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
@@ -200,3 +204,25 @@ static inline int list_empty(const struct list_head *head)
 		n = list_entry(pos->member.prev, typeof(*pos), member);	\
 	     &pos->member != (head); 					\
 	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))
+
+/**
+ * Get the first element from a list
+ * \param ptr the list head to take the element from.
+ * \param type The type of the struct this is embedded in.
+ * \param member The name of the list_struct within the struct.
+ *
+ * Note that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+        list_entry((ptr)->next, type, member)
+
+/**
+ * Test whether a list has just one entry.
+ *
+ * \param head The list to test.
+ */
+static inline int list_is_singular(const struct list_head *head)
+{
+	return !list_empty(head) && (head->next == head->prev);
+}
+