[ccan] [RESEND PATCH 1/5] list: list_add_after and list_add_before functions
Eric Wong
normalperson at yhbt.net
Sat Oct 25 09:02:28 AEDT 2014
These make it easy to add a new element before or after an
existing element in the middle of the list.
The existing list_add and list_add_tail functions are trivially
reimplemented on top of these new functions.
Signed-off-by: Eric Wong <normalperson at yhbt.net>
Reviewed-by: David Gibson <david at gibson.dropbear.id.au>
---
ccan/list/list.h | 68 +++++++++++++++++++++++++++++++++++++++++++++-------
ccan/list/test/run.c | 40 ++++++++++++++++++++++++++++++-
2 files changed, 98 insertions(+), 10 deletions(-)
diff --git a/ccan/list/list.h b/ccan/list/list.h
index cdd5eeb..5c1159f 100644
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -158,6 +158,36 @@ static inline void list_node_init(struct list_node *n)
}
/**
+ * list_add_after - add an entry after an existing node in a linked list
+ * @h: the list_head to add the node to (for debugging)
+ * @p: the existing list_node to add the node after
+ * @n: the new list_node to add to the list.
+ *
+ * The existing list_node must already be a member of the list.
+ * The new list_node does not need to be initialized; it will be overwritten.
+ *
+ * Example:
+ * struct child c1, c2, c3;
+ * LIST_HEAD(h);
+ *
+ * list_add_tail(&h, &c1.list);
+ * list_add_tail(&h, &c3.list);
+ * list_add_after(&h, &c1.list, &c2.list);
+ */
+#define list_add_after(h, p, n) list_add_after_(h, p, n, LIST_LOC)
+static inline void list_add_after_(struct list_head *h,
+ struct list_node *p,
+ struct list_node *n,
+ const char *abortstr)
+{
+ n->next = p->next;
+ n->prev = p;
+ p->next->prev = n;
+ p->next = n;
+ (void)list_debug(h, abortstr);
+}
+
+/**
* list_add - add an entry at the start of a linked list.
* @h: the list_head to add the node to
* @n: the list_node to add to the list.
@@ -175,10 +205,34 @@ static inline void list_add_(struct list_head *h,
struct list_node *n,
const char *abortstr)
{
- n->next = h->n.next;
- n->prev = &h->n;
- h->n.next->prev = n;
- h->n.next = n;
+ list_add_after_(h, &h->n, n, abortstr);
+}
+
+/**
+ * list_add_before - add an entry before an existing node in a linked list
+ * @h: the list_head to add the node to (for debugging)
+ * @p: the existing list_node to add the node before
+ * @n: the new list_node to add to the list.
+ *
+ * The existing list_node must already be a member of the list.
+ * The new list_node does not need to be initialized; it will be overwritten.
+ *
+ * Example:
+ * list_head_init(&h);
+ * list_add_tail(&h, &c1.list);
+ * list_add_tail(&h, &c3.list);
+ * list_add_before(&h, &c3.list, &c2.list);
+ */
+#define list_add_before(h, p, n) list_add_before_(h, p, n, LIST_LOC)
+static inline void list_add_before_(struct list_head *h,
+ struct list_node *p,
+ struct list_node *n,
+ const char *abortstr)
+{
+ n->next = p;
+ n->prev = p->prev;
+ p->prev->next = n;
+ p->prev = n;
(void)list_debug(h, abortstr);
}
@@ -197,11 +251,7 @@ static inline void list_add_tail_(struct list_head *h,
struct list_node *n,
const char *abortstr)
{
- n->next = &h->n;
- n->prev = h->n.prev;
- h->n.prev->next = n;
- h->n.prev = n;
- (void)list_debug(h, abortstr);
+ list_add_before_(h, &h->n, n, abortstr);
}
/**
diff --git a/ccan/list/test/run.c b/ccan/list/test/run.c
index 88c3835..2f1acc7 100644
--- a/ccan/list/test/run.c
+++ b/ccan/list/test/run.c
@@ -25,7 +25,7 @@ int main(int argc, char *argv[])
opaque_t *q, *nq;
struct list_head opaque_list = LIST_HEAD_INIT(opaque_list);
- plan_tests(70);
+ plan_tests(79);
/* Test LIST_HEAD, LIST_HEAD_INIT, list_empty and check_list */
ok1(list_empty(&static_list));
ok1(list_check(&static_list, NULL));
@@ -215,5 +215,43 @@ int main(int argc, char *argv[])
ok1(list_top(&parent.children, struct child, list) == NULL);
ok1(list_tail(&parent.children, struct child, list) == NULL);
ok1(list_pop(&parent.children, struct child, list) == NULL);
+
+ /* Test list_add_before and list_add_after */
+ list_add(&parent.children, &c1.list);
+ list_add_after(&parent.children, &c1.list, &c2.list);
+ ok1(list_check(&parent.children, "list_add_after"));
+
+ i = 0;
+ list_for_each(&parent.children, c, list) {
+ switch (i++) {
+ case 0:
+ ok1(c == &c1);
+ break;
+ case 1:
+ ok1(c == &c2);
+ break;
+ }
+ }
+ ok1(i == 2);
+
+ list_add_before(&parent.children, &c2.list, &c3.list);
+ ok1(list_check(&parent.children, "list_add_before"));
+
+ i = 0;
+ list_for_each(&parent.children, c, list) {
+ switch (i++) {
+ case 0:
+ ok1(c == &c1);
+ break;
+ case 1:
+ ok1(c == &c3);
+ break;
+ case 2:
+ ok1(c == &c2);
+ break;
+ }
+ }
+ ok1(i == 3);
+
return exit_status();
}
--
EW
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