Add list_prev_entry, list_next_entry

[petitboot] / lib / list / list.h

diff --git a/lib/list/list.h b/lib/list/list.h
index dfe4813e52f6f9fe331227eff2eb998fbf52f6ee..7f9955f93115e2761fbe1b0ec94398480d40e8a8 100644 (file)
--- a/lib/list/list.h
+++ b/lib/list/list.h
@@ -22,17 +22,24 @@ struct list {
 #define list_for_each(_list, _pos) \
        for (_pos = (_list)->head.next; _pos != ((_list)->head); _pos = _pos->next)
 
-#define list_entry(_ptr, _type, _member) \
-       container_of(_ptr, _type, _member)
+#define list_entry(_ptr, _type, _member, _list) \
+       (&container_of(_ptr, _type, _member)->_member == &((_list)->head) \
+       ? NULL \
+       : container_of(_ptr, _type, _member))
+
+#define list_prev_entry(_list, _pos, _member) \
+       list_entry(_pos->_member.prev, typeof(*_pos), _member, _list)
+
+#define list_next_entry(_list, _pos, _member) \
+       list_entry(_pos->_member.next, typeof(*_pos), _member, _list)
 
 #define list_for_each_entry(_list, _pos, _member) \
-       for (_pos = list_entry((_list)->head.next, typeof(*_pos), _member); \
-            &_pos->_member != &(_list)->head; \
-            _pos = list_entry(_pos->_member.next, typeof(*_pos), _member))
+       for (_pos = list_entry((_list)->head.next, typeof(*_pos), _member, _list); \
+               _pos; _pos = list_next_entry(_list, _pos, _member))
 
 #define list_for_each_entry_continue(_list, _pos, _member) \
-       for (; &_pos->_member != &(_list)->head; \
-               _pos = list_entry(_pos->_member.next, typeof(*_pos), _member))
+       for (; _pos; _pos = list_next_entry(_list, _pos, _member))
+
 
 #define STATIC_LIST(_list) static struct list _list = { \
        .head = { \