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