-/* Licensed under LGPLv2.1+ - see LICENSE file for details */
+/* Licensed under BSD-MIT - see LICENSE file for details */
#ifndef CCAN_LIST_H
#define CCAN_LIST_H
#include <stdbool.h>
* printf("Name: %s\n", child->name);
*/
#define list_for_each(h, i, member) \
- for (i = container_of_var(list_debug(h)->n.next, i, member); \
- &i->member != &(h)->n; \
- i = container_of_var(i->member.next, i, member))
+ list_for_each_off(h, i, list_off_var_(i, member))
/**
* list_for_each_rev - iterate through a list backwards.
* }
*/
#define list_for_each_safe(h, i, nxt, member) \
- for (i = container_of_var(list_debug(h)->n.next, i, member), \
- nxt = container_of_var(i->member.next, i, member); \
- &i->member != &(h)->n; \
- i = nxt, nxt = container_of_var(i->member.next, i, member))
+ list_for_each_safe_off(h, i, nxt, list_off_var_(i, member))
+
+/**
+ * list_for_each_off - iterate through a list of memory regions.
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * This is a low-level wrapper to iterate @i over the entire list, used to
+ * implement all oher, more high-level, for-each constructs. It's a for loop,
+ * so you can break and continue as normal.
+ *
+ * WARNING! Being the low-level macro that it is, this wrapper doesn't know
+ * nor care about the type of @i. The only assumtion made is that @i points
+ * to a chunk of memory that at some @offset, relative to @i, contains a
+ * properly filled `struct node_list' which in turn contains pointers to
+ * memory chunks and it's turtles all the way down. Whith all that in mind
+ * remember that given the wrong pointer/offset couple this macro will
+ * happilly churn all you memory untill SEGFAULT stops it, in other words
+ * caveat emptor.
+ *
+ * It is worth mentioning that one of legitimate use-cases for that wrapper
+ * is operation on opaque types with known offset for `struct list_node'
+ * member(preferably 0), because it allows you not to disclose the type of
+ * @i.
+ *
+ * Example:
+ * list_for_each_off(&parent->children, child,
+ * offsetof(struct child, list))
+ * printf("Name: %s\n", child->name);
+ */
+#define list_for_each_off(h, i, off) \
+ for (i = list_node_to_off_(list_debug(h)->n.next, (off)); \
+ list_node_from_off_((void *)i, (off)) != &(h)->n; \
+ i = list_node_to_off_(list_node_from_off_((void *)i, (off))->next, \
+ (off)))
+
+/**
+ * list_for_each_safe_off - iterate through a list of memory regions, maybe
+ * during deletion
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @nxt: the structure containing the list_node
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * For details see `list_for_each_off' and `list_for_each_safe'
+ * descriptions.
+ *
+ * Example:
+ * list_for_each_safe_off(&parent->children, child,
+ * next, offsetof(struct child, list))
+ * printf("Name: %s\n", child->name);
+ */
+#define list_for_each_safe_off(h, i, nxt, off) \
+ for (i = list_node_to_off_(list_debug(h)->n.next, (off)), \
+ nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \
+ (off)); \
+ list_node_from_off_(i, (off)) != &(h)->n; \
+ i = nxt, \
+ nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \
+ (off)))
+
+
+/* Other -off variants. */
+#define list_entry_off(n, type, off) \
+ ((type *)list_node_from_off_((n), (off)))
+
+#define list_head_off(h, type, off) \
+ ((type *)list_head_off((h), (off)))
+
+#define list_tail_off(h, type, off) \
+ ((type *)list_tail_((h), (off)))
+
+#define list_add_off(h, n, off) \
+ list_add((h), list_node_from_off_((n), (off)))
+
+#define list_del_off(n, off) \
+ list_del(list_node_from_off_((n), (off)))
+
+#define list_del_from_off(h, n, off) \
+ list_del_from(h, list_node_from_off_((n), (off)))
+
+/* Offset helper functions so we only single-evaluate. */
+static inline void *list_node_to_off_(struct list_node *node, size_t off)
+{
+ return (void *)((char *)node - off);
+}
+static inline struct list_node *list_node_from_off_(void *ptr, size_t off)
+{
+ return (struct list_node *)((char *)ptr + off);
+}
/* Get the offset of the member, but make sure it's a list_node. */
#define list_off_(type, member) \
(container_off(type, member) + \
check_type(((type *)0)->member, struct list_node))
+#define list_off_var_(var, member) \
+ (container_off_var(var, member) + \
+ check_type(var->member, struct list_node))
+
#endif /* CCAN_LIST_H */
projects / ccan / blobdiff