/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <stdbool.h>
#include <stddef.h>
#include "util.h"
+#include "openvswitch/list.h"
-/* Doubly linked list head or element. */
-struct list {
- struct list *prev; /* Previous list element. */
- struct list *next; /* Next list element. */
-};
+/* "struct ovs_list" with pointers that will (probably) cause segfaults if
+ * dereferenced and, better yet, show up clearly in a debugger. */
+#define OVS_LIST_POISON \
+(struct ovs_list) { (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL, \
+ (struct ovs_list *) (uintptr_t) 0xccccccccccccccccULL }
-#define LIST_INITIALIZER(LIST) { LIST, LIST }
-
-void list_init(struct list *);
+static inline void list_init(struct ovs_list *);
+static inline void list_poison(struct ovs_list *);
/* List insertion. */
-void list_insert(struct list *, struct list *);
-void list_splice(struct list *before, struct list *first, struct list *last);
-void list_push_front(struct list *, struct list *);
-void list_push_back(struct list *, struct list *);
-void list_replace(struct list *, const struct list *);
-void list_moved(struct list *);
+static inline void list_insert(struct ovs_list *, struct ovs_list *);
+static inline void list_splice(struct ovs_list *before, struct ovs_list *first,
+ struct ovs_list *last);
+static inline void list_push_front(struct ovs_list *, struct ovs_list *);
+static inline void list_push_back(struct ovs_list *, struct ovs_list *);
+static inline void list_replace(struct ovs_list *, const struct ovs_list *);
+static inline void list_moved(struct ovs_list *, const struct ovs_list *orig);
+static inline void list_move(struct ovs_list *dst, struct ovs_list *src);
/* List removal. */
-struct list *list_remove(struct list *);
-struct list *list_pop_front(struct list *);
-struct list *list_pop_back(struct list *);
+static inline struct ovs_list *list_remove(struct ovs_list *);
+static inline struct ovs_list *list_pop_front(struct ovs_list *);
+static inline struct ovs_list *list_pop_back(struct ovs_list *);
/* List elements. */
-struct list *list_front(struct list *);
-struct list *list_back(struct list *);
+static inline struct ovs_list *list_front(const struct ovs_list *);
+static inline struct ovs_list *list_back(const struct ovs_list *);
/* List properties. */
-size_t list_size(const struct list *);
-bool list_is_empty(const struct list *);
+static inline size_t list_size(const struct ovs_list *);
+static inline bool list_is_empty(const struct ovs_list *);
+static inline bool list_is_singleton(const struct ovs_list *);
+static inline bool list_is_short(const struct ovs_list *);
#define LIST_FOR_EACH(ITER, MEMBER, LIST) \
- for (ITER = OBJECT_CONTAINING((LIST)->next, ITER, MEMBER); \
+ for (INIT_CONTAINER(ITER, (LIST)->next, MEMBER); \
+ &(ITER)->MEMBER != (LIST); \
+ ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.next, MEMBER))
+#define LIST_FOR_EACH_CONTINUE(ITER, MEMBER, LIST) \
+ for (ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.next, MEMBER); \
&(ITER)->MEMBER != (LIST); \
- ITER = OBJECT_CONTAINING((ITER)->MEMBER.next, ITER, MEMBER))
+ ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.next, MEMBER))
#define LIST_FOR_EACH_REVERSE(ITER, MEMBER, LIST) \
- for (ITER = OBJECT_CONTAINING((LIST)->prev, ITER, MEMBER); \
+ for (INIT_CONTAINER(ITER, (LIST)->prev, MEMBER); \
&(ITER)->MEMBER != (LIST); \
- ITER = OBJECT_CONTAINING((ITER)->MEMBER.prev, ITER, MEMBER))
-#define LIST_FOR_EACH_SAFE(ITER, NEXT, MEMBER, LIST) \
- for (ITER = OBJECT_CONTAINING((LIST)->next, ITER, MEMBER); \
- (NEXT = OBJECT_CONTAINING((ITER)->MEMBER.next, ITER, MEMBER), \
- &(ITER)->MEMBER != (LIST)); \
- ITER = NEXT)
+ ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.prev, MEMBER))
+#define LIST_FOR_EACH_REVERSE_CONTINUE(ITER, MEMBER, LIST) \
+ for (ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.prev, MEMBER); \
+ &(ITER)->MEMBER != (LIST); \
+ ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.prev, MEMBER))
+#define LIST_FOR_EACH_SAFE(ITER, NEXT, MEMBER, LIST) \
+ for (INIT_CONTAINER(ITER, (LIST)->next, MEMBER); \
+ (&(ITER)->MEMBER != (LIST) \
+ ? INIT_CONTAINER(NEXT, (ITER)->MEMBER.next, MEMBER), 1 \
+ : 0); \
+ (ITER) = (NEXT))
+#define LIST_FOR_EACH_POP(ITER, MEMBER, LIST) \
+ while (!list_is_empty(LIST) \
+ && (INIT_CONTAINER(ITER, list_pop_front(LIST), MEMBER), 1))
+\f
+/* Inline implementations. */
+
+/* Initializes 'list' as an empty list. */
+static inline void
+list_init(struct ovs_list *list)
+{
+ list->next = list->prev = list;
+}
+
+/* Initializes 'list' with pointers that will (probably) cause segfaults if
+ * dereferenced and, better yet, show up clearly in a debugger. */
+static inline void
+list_poison(struct ovs_list *list)
+{
+ *list = OVS_LIST_POISON;
+}
+
+/* Inserts 'elem' just before 'before'. */
+static inline void
+list_insert(struct ovs_list *before, struct ovs_list *elem)
+{
+ elem->prev = before->prev;
+ elem->next = before;
+ before->prev->next = elem;
+ before->prev = elem;
+}
+
+/* Removes elements 'first' though 'last' (exclusive) from their current list,
+ then inserts them just before 'before'. */
+static inline void
+list_splice(struct ovs_list *before, struct ovs_list *first, struct ovs_list *last)
+{
+ if (first == last) {
+ return;
+ }
+ last = last->prev;
+
+ /* Cleanly remove 'first'...'last' from its current list. */
+ first->prev->next = last->next;
+ last->next->prev = first->prev;
+
+ /* Splice 'first'...'last' into new list. */
+ first->prev = before->prev;
+ last->next = before;
+ before->prev->next = first;
+ before->prev = last;
+}
+
+/* Inserts 'elem' at the beginning of 'list', so that it becomes the front in
+ 'list'. */
+static inline void
+list_push_front(struct ovs_list *list, struct ovs_list *elem)
+{
+ list_insert(list->next, elem);
+}
+
+/* Inserts 'elem' at the end of 'list', so that it becomes the back in
+ * 'list'. */
+static inline void
+list_push_back(struct ovs_list *list, struct ovs_list *elem)
+{
+ list_insert(list, elem);
+}
+
+/* Puts 'elem' in the position currently occupied by 'position'.
+ * Afterward, 'position' is not part of a list. */
+static inline void
+list_replace(struct ovs_list *element, const struct ovs_list *position)
+{
+ element->next = position->next;
+ element->next->prev = element;
+ element->prev = position->prev;
+ element->prev->next = element;
+}
+
+/* Adjusts pointers around 'list' to compensate for 'list' having been moved
+ * around in memory (e.g. as a consequence of realloc()), with original
+ * location 'orig'.
+ *
+ * ('orig' likely points to freed memory, but this function does not
+ * dereference 'orig', it only compares it to 'list'. In a very pedantic
+ * language lawyer sense, this still yields undefined behavior, but it works
+ * with actual compilers.) */
+static inline void
+list_moved(struct ovs_list *list, const struct ovs_list *orig)
+{
+ if (list->next == orig) {
+ list_init(list);
+ } else {
+ list->prev->next = list->next->prev = list;
+ }
+}
+
+/* Initializes 'dst' with the contents of 'src', compensating for moving it
+ * around in memory. The effect is that, if 'src' was the head of a list, now
+ * 'dst' is the head of a list containing the same elements. */
+static inline void
+list_move(struct ovs_list *dst, struct ovs_list *src)
+{
+ *dst = *src;
+ list_moved(dst, src);
+}
+
+/* Removes 'elem' from its list and returns the element that followed it.
+ Undefined behavior if 'elem' is not in a list. */
+static inline struct ovs_list *
+list_remove(struct ovs_list *elem)
+{
+ elem->prev->next = elem->next;
+ elem->next->prev = elem->prev;
+ return elem->next;
+}
+
+/* Removes the front element from 'list' and returns it. Undefined behavior if
+ 'list' is empty before removal. */
+static inline struct ovs_list *
+list_pop_front(struct ovs_list *list)
+{
+ struct ovs_list *front = list->next;
+
+ list_remove(front);
+ return front;
+}
+
+/* Removes the back element from 'list' and returns it.
+ Undefined behavior if 'list' is empty before removal. */
+static inline struct ovs_list *
+list_pop_back(struct ovs_list *list)
+{
+ struct ovs_list *back = list->prev;
+
+ list_remove(back);
+ return back;
+}
+
+/* Returns the front element in 'list_'.
+ Undefined behavior if 'list_' is empty. */
+static inline struct ovs_list *
+list_front(const struct ovs_list *list_)
+{
+ struct ovs_list *list = CONST_CAST(struct ovs_list *, list_);
+
+ ovs_assert(!list_is_empty(list));
+
+ return list->next;
+}
+
+/* Returns the back element in 'list_'.
+ Undefined behavior if 'list_' is empty. */
+static inline struct ovs_list *
+list_back(const struct ovs_list *list_)
+{
+ struct ovs_list *list = CONST_CAST(struct ovs_list *, list_);
+
+ ovs_assert(!list_is_empty(list));
+
+ return list->prev;
+}
+
+/* Returns the number of elements in 'list'.
+ Runs in O(n) in the number of elements. */
+static inline size_t
+list_size(const struct ovs_list *list)
+{
+ const struct ovs_list *e;
+ size_t cnt = 0;
+
+ for (e = list->next; e != list; e = e->next) {
+ cnt++;
+ }
+ return cnt;
+}
+
+/* Returns true if 'list' is empty, false otherwise. */
+static inline bool
+list_is_empty(const struct ovs_list *list)
+{
+ return list->next == list;
+}
+
+/* Returns true if 'list' has exactly 1 element, false otherwise. */
+static inline bool
+list_is_singleton(const struct ovs_list *list)
+{
+ return list_is_short(list) && !list_is_empty(list);
+}
+
+/* Returns true if 'list' has 0 or 1 elements, false otherwise. */
+static inline bool
+list_is_short(const struct ovs_list *list)
+{
+ return list->next == list->prev;
+}
#endif /* list.h */
projects / cascardo / ovs.git / blobdiff