109 lines
5.7 KiB
C
109 lines
5.7 KiB
C
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/* Copyright (c) 2013, Ben Noordhuis <info@bnoordhuis.nl>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef QUEUE_H_
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#define QUEUE_H_
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#include <stddef.h>
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typedef void *QUEUE[2];
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/* Private macros. */
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#define QUEUE_NEXT(q) (*(QUEUE **) &((*(q))[0]))
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#define QUEUE_PREV(q) (*(QUEUE **) &((*(q))[1]))
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#define QUEUE_PREV_NEXT(q) (QUEUE_NEXT(QUEUE_PREV(q)))
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#define QUEUE_NEXT_PREV(q) (QUEUE_PREV(QUEUE_NEXT(q)))
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/* Public macros. */
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#define QUEUE_DATA(ptr, type, field) \
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((type *) ((char *) (ptr) - offsetof(type, field)))
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/* Important note: mutating the list while QUEUE_FOREACH is
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* iterating over its elements results in undefined behavior.
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*/
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#define QUEUE_FOREACH(q, h) \
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for ((q) = QUEUE_NEXT(h); (q) != (h); (q) = QUEUE_NEXT(q))
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#define QUEUE_EMPTY(q) \
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((const QUEUE *) (q) == (const QUEUE *) QUEUE_NEXT(q))
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#define QUEUE_HEAD(q) \
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(QUEUE_NEXT(q))
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#define QUEUE_INIT(q) \
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do { \
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QUEUE_NEXT(q) = (q); \
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QUEUE_PREV(q) = (q); \
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} \
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while (0)
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#define QUEUE_ADD(h, n) \
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do { \
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QUEUE_PREV_NEXT(h) = QUEUE_NEXT(n); \
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QUEUE_NEXT_PREV(n) = QUEUE_PREV(h); \
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QUEUE_PREV(h) = QUEUE_PREV(n); \
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QUEUE_PREV_NEXT(h) = (h); \
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} \
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while (0)
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#define QUEUE_SPLIT(h, q, n) \
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do { \
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QUEUE_PREV(n) = QUEUE_PREV(h); \
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QUEUE_PREV_NEXT(n) = (n); \
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QUEUE_NEXT(n) = (q); \
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QUEUE_PREV(h) = QUEUE_PREV(q); \
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QUEUE_PREV_NEXT(h) = (h); \
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QUEUE_PREV(q) = (n); \
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} \
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while (0)
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#define QUEUE_MOVE(h, n) \
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do { \
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if (QUEUE_EMPTY(h)) \
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QUEUE_INIT(n); \
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else { \
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QUEUE* q = QUEUE_HEAD(h); \
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QUEUE_SPLIT(h, q, n); \
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} \
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} \
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while (0)
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#define QUEUE_INSERT_HEAD(h, q) \
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do { \
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QUEUE_NEXT(q) = QUEUE_NEXT(h); \
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QUEUE_PREV(q) = (h); \
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QUEUE_NEXT_PREV(q) = (q); \
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QUEUE_NEXT(h) = (q); \
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} \
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while (0)
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#define QUEUE_INSERT_TAIL(h, q) \
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do { \
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QUEUE_NEXT(q) = (h); \
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QUEUE_PREV(q) = QUEUE_PREV(h); \
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QUEUE_PREV_NEXT(q) = (q); \
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QUEUE_PREV(h) = (q); \
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} \
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while (0)
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#define QUEUE_REMOVE(q) \
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do { \
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QUEUE_PREV_NEXT(q) = QUEUE_NEXT(q); \
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QUEUE_NEXT_PREV(q) = QUEUE_PREV(q); \
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} \
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while (0)
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#endif /* QUEUE_H_ */
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