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* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2015 Nicira, Inc.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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/* Initializes 'list' as an empty list. */
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list_init(struct list *list)
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list->next = list->prev = list;
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/* Initializes 'list' with pointers that will (probably) cause segfaults if
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* dereferenced and, better yet, show up clearly in a debugger. */
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list_poison(struct list *list)
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memset(list, 0xcc, sizeof *list);
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/* Inserts 'elem' just before 'before'. */
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list_insert(struct list *before, struct list *elem)
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elem->prev = before->prev;
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before->prev->next = elem;
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/* Removes elements 'first' though 'last' (exclusive) from their current list,
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then inserts them just before 'before'. */
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list_splice(struct list *before, struct list *first, struct list *last)
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/* Cleanly remove 'first'...'last' from its current list. */
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first->prev->next = last->next;
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last->next->prev = first->prev;
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/* Splice 'first'...'last' into new list. */
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first->prev = before->prev;
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before->prev->next = first;
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/* Inserts 'elem' at the beginning of 'list', so that it becomes the front in
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list_push_front(struct list *list, struct list *elem)
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list_insert(list->next, elem);
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/* Inserts 'elem' at the end of 'list', so that it becomes the back in
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list_push_back(struct list *list, struct list *elem)
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list_insert(list, elem);
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/* Puts 'elem' in the position currently occupied by 'position'.
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* Afterward, 'position' is not part of a list. */
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list_replace(struct list *element, const struct list *position)
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element->next = position->next;
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element->next->prev = element;
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element->prev = position->prev;
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element->prev->next = element;
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/* Adjusts pointers around 'list' to compensate for 'list' having been moved
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* around in memory (e.g. as a consequence of realloc()), with original
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* ('orig' likely points to freed memory, but this function does not
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* dereference 'orig', it only compares it to 'list'. In a very pedantic
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* language lawyer sense, this still yields undefined behavior, but it works
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* with actual compilers.) */
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list_moved(struct list *list, const struct list *orig)
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if (list->next == orig) {
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list->prev->next = list->next->prev = list;
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/* Initializes 'dst' with the contents of 'src', compensating for moving it
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* around in memory. The effect is that, if 'src' was the head of a list, now
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* 'dst' is the head of a list containing the same elements. */
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list_move(struct list *dst, struct list *src)
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list_moved(dst, src);
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/* Removes 'elem' from its list and returns the element that followed it.
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Undefined behavior if 'elem' is not in a list. */
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list_remove(struct list *elem)
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elem->prev->next = elem->next;
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elem->next->prev = elem->prev;
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/* Removes the front element from 'list' and returns it. Undefined behavior if
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'list' is empty before removal. */
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list_pop_front(struct list *list)
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struct list *front = list->next;
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/* Removes the back element from 'list' and returns it.
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Undefined behavior if 'list' is empty before removal. */
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list_pop_back(struct list *list)
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struct list *back = list->prev;
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/* Returns the front element in 'list_'.
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Undefined behavior if 'list_' is empty. */
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list_front(const struct list *list_)
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struct list *list = CONST_CAST(struct list *, list_);
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ovs_assert(!list_is_empty(list));
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/* Returns the back element in 'list_'.
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Undefined behavior if 'list_' is empty. */
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list_back(const struct list *list_)
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struct list *list = CONST_CAST(struct list *, list_);
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ovs_assert(!list_is_empty(list));
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/* Returns the number of elements in 'list'.
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Runs in O(n) in the number of elements. */
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list_size(const struct list *list)
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const struct list *e;
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for (e = list->next; e != list; e = e->next) {
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/* Returns true if 'list' is empty, false otherwise. */
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list_is_empty(const struct list *list)
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return list->next == list;
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/* Returns true if 'list' has exactly 1 element, false otherwise. */
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list_is_singleton(const struct list *list)
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return list_is_short(list) && !list_is_empty(list);
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/* Returns true if 'list' has 0 or 1 elements, false otherwise. */
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list_is_short(const struct list *list)
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return list->next == list->prev;
added
removed
lib/list.c
