2fe1d7b0fe
If we iterate over a non-empty list and pass the same pointer for start and head, then we will never leave that loop. It might be unclear why this is supported at all as we can simply use the shl_dlist_for_each() for that. However, it makes code a lot easier to read if the user can simply use shl_dlist_for_each_but_one() without checking whether they passed the same for start and head. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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* shl - Double Linked List
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*
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* Copyright (c) 2011-2012 David Herrmann <dh.herrmann@googlemail.com>
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* Copyright (c) 2011 University of Tuebingen
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* A simple double linked list implementation
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*/
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#ifndef SHL_DLIST_H
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#define SHL_DLIST_H
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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/* miscellaneous */
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#define shl_offsetof(pointer, type, member) ({ \
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const typeof(((type*)0)->member) *__ptr = (pointer); \
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(type*)(((char*)__ptr) - offsetof(type, member)); \
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})
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/* double linked list */
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struct shl_dlist {
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struct shl_dlist *next;
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struct shl_dlist *prev;
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};
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#define SHL_DLIST_INIT(head) { &(head), &(head) }
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static inline void shl_dlist_init(struct shl_dlist *list)
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{
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list->next = list;
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list->prev = list;
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}
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static inline void shl_dlist__link(struct shl_dlist *prev,
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struct shl_dlist *next,
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struct shl_dlist *n)
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{
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next->prev = n;
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n->next = next;
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n->prev = prev;
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prev->next = n;
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}
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static inline void shl_dlist_link(struct shl_dlist *head,
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struct shl_dlist *n)
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{
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return shl_dlist__link(head, head->next, n);
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}
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static inline void shl_dlist_link_tail(struct shl_dlist *head,
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struct shl_dlist *n)
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{
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return shl_dlist__link(head->prev, head, n);
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}
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static inline void shl_dlist__unlink(struct shl_dlist *prev,
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struct shl_dlist *next)
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{
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next->prev = prev;
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prev->next = next;
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}
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static inline void shl_dlist_unlink(struct shl_dlist *e)
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{
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shl_dlist__unlink(e->prev, e->next);
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e->prev = NULL;
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e->next = NULL;
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}
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static inline bool shl_dlist_empty(struct shl_dlist *head)
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{
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return head->next == head;
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}
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#define shl_dlist_entry(ptr, type, member) \
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shl_offsetof((ptr), type, member)
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#define shl_dlist_for_each(iter, head) \
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for (iter = (head)->next; iter != (head); iter = iter->next)
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#define shl_dlist_for_each_but_one(iter, start, head) \
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for (iter = ((start)->next == (head)) ? \
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(start)->next->next : \
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(start)->next; \
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iter != (start); \
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iter = (iter->next == (head) && (start) != (head)) ? \
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iter->next->next : \
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iter->next)
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#define shl_dlist_for_each_safe(iter, tmp, head) \
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for (iter = (head)->next, tmp = iter->next; iter != (head); \
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iter = tmp, tmp = iter->next)
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#define shl_dlist_for_each_reverse(iter, head) \
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for (iter = (head)->prev; iter != (head); iter = iter->prev)
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#define shl_dlist_for_each_reverse_but_one(iter, start, head) \
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for (iter = ((start)->prev == (head)) ? \
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(start)->prev->prev : \
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(start)->prev; \
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iter != (start); \
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iter = (iter->prev == (head) && (start) != (head)) ? \
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iter->prev->prev : \
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iter->prev)
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#define shl_dlist_for_each_reverse_safe(iter, tmp, head) \
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for (iter = (head)->prev, tmp = iter->prev; iter != (head); \
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iter = tmp, tmp = iter->prev)
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#endif /* SHL_DLIST_H */
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