A few comment fixes

[wimlib] / include / wimlib / list.h

diff --git a/include/wimlib/list.h b/include/wimlib/list.h
index 4ac2d0b414f38e8c99d9161e9a144513256ec7c6..6073c23b8088b317baa31cd7649a5860e25c7790 100644 (file)
--- a/include/wimlib/list.h
+++ b/include/wimlib/list.h
@@ -249,6 +249,56 @@ static inline void list_splice_tail(struct list_head *list,
 #define list_entry(ptr, type, member) \
        container_of(ptr, type, member)
 
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr:       the list head to take the element from.
+ * @type:      the type of the struct this is embedded in.
+ * @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)
+
+/**
+ * list_last_entry - get the last element from a list
+ * @ptr:       the list head to take the element from.
+ * @type:      the type of the struct this is embedded in.
+ * @member:    the name of the list_struct within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member) \
+       list_entry((ptr)->prev, type, member)
+
+/**
+ * list_first_entry_or_null - get the first element from a list
+ * @ptr:       the list head to take the element from.
+ * @type:      the type of the struct this is embedded in.
+ * @member:    the name of the list_struct within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_first_entry_or_null(ptr, type, member) \
+       (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
+
+/**
+ * list_next_entry - get the next element in list
+ * @pos:       the type * to cursor
+ * @member:    the name of the list_struct within the struct.
+ */
+#define list_next_entry(pos, member) \
+       list_entry((pos)->member.next, typeof(*(pos)), member)
+
+/**
+ * list_prev_entry - get the prev element in list
+ * @pos:       the type * to cursor
+ * @member:    the name of the list_struct within the struct.
+ */
+#define list_prev_entry(pos, member) \
+       list_entry((pos)->member.prev, typeof(*(pos)), member)
+
+
 /**
  * list_for_each       -       iterate over a list
  * @pos:       the &struct list_head to use as a loop cursor.
@@ -274,9 +324,20 @@ static inline void list_splice_tail(struct list_head *list,
  * @member:    the name of the list_struct within the struct.
  */
 #define list_for_each_entry(pos, head, member)                         \
-       for (pos = list_entry((head)->next, typeof(*pos), member);      \
-            &pos->member != (head);    \
-            pos = list_entry(pos->member.next, typeof(*pos), member))
+       for (pos = list_first_entry(head, typeof(*pos), member);        \
+            &pos->member != (head);                                    \
+            pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_reverse - iterate backwards over list of given type.
+ * @pos:       the type * to use as a loop cursor.
+ * @head:      the head for your list.
+ * @member:    the name of the list_struct within the struct.
+ */
+#define list_for_each_entry_reverse(pos, head, member)                 \
+       for (pos = list_last_entry(head, typeof(*pos), member);         \
+            &pos->member != (head);                                    \
+            pos = list_prev_entry(pos, member))
 
 /**
  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
@@ -288,7 +349,7 @@ static inline void list_splice_tail(struct list_head *list,
 #define list_for_each_entry_safe(pos, n, head, member)                 \
        for (pos = list_entry((head)->next, typeof(*pos), member),      \
                n = list_entry(pos->member.next, typeof(*pos), member); \
-            &pos->member != (head);                                    \
+            &pos->member != (head);                                    \
             pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
 /*
@@ -383,9 +444,9 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
  * @head:      the head for your list.
  * @member:    the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry_safe(tpos, pos, n, head, member)           \
+#define hlist_for_each_entry_safe(tpos, pos, n, head, member)           \
        for (pos = (head)->first;                                        \
-            pos && ({ n = pos->next; 1; }) &&                           \
+            pos && ({ n = pos->next; 1; }) &&                           \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = n)