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apr_ring.h
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1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*
18 * This code draws heavily from the 4.4BSD <sys/queue.h> macros
19 * and Dean Gaudet's "splim/ring.h".
20 * <http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/sys/queue.h>
21 * <http://www.arctic.org/~dean/splim/>
22 *
23 * We'd use Dean's code directly if we could guarantee the
24 * availability of inline functions.
25 */
26
27#ifndef APR_RING_H
28#define APR_RING_H
29
35/*
36 * for offsetof()
37 */
38#include "apr_general.h"
39
70#define APR_RING_ENTRY(elem) \
71 struct { \
72 struct elem * volatile next; \
73 struct elem * volatile prev; \
74 }
75
91#define APR_RING_HEAD(head, elem) \
92 struct head { \
93 struct elem * volatile next; \
94 struct elem * volatile prev; \
95 }
96
159#define APR_RING_SENTINEL(hp, elem, link) \
160 (struct elem *)((char *)(&(hp)->next) - APR_OFFSETOF(struct elem, link))
161
166#define APR_RING_FIRST(hp) (hp)->next
171#define APR_RING_LAST(hp) (hp)->prev
177#define APR_RING_NEXT(ep, link) (ep)->link.next
183#define APR_RING_PREV(ep, link) (ep)->link.prev
184
185
192#define APR_RING_INIT(hp, elem, link) do { \
193 APR_RING_FIRST((hp)) = APR_RING_SENTINEL((hp), elem, link); \
194 APR_RING_LAST((hp)) = APR_RING_SENTINEL((hp), elem, link); \
195 } while (0)
196
204#define APR_RING_EMPTY(hp, elem, link) \
205 (APR_RING_FIRST((hp)) == APR_RING_SENTINEL((hp), elem, link))
206
212#define APR_RING_ELEM_INIT(ep, link) do { \
213 APR_RING_NEXT((ep), link) = (ep); \
214 APR_RING_PREV((ep), link) = (ep); \
215 } while (0)
216
217
228#define APR_RING_SPLICE_BEFORE(lep, ep1, epN, link) do { \
229 APR_RING_NEXT((epN), link) = (lep); \
230 APR_RING_PREV((ep1), link) = APR_RING_PREV((lep), link); \
231 APR_RING_NEXT(APR_RING_PREV((lep), link), link) = (ep1); \
232 APR_RING_PREV((lep), link) = (epN); \
233 } while (0)
234
245#define APR_RING_SPLICE_AFTER(lep, ep1, epN, link) do { \
246 APR_RING_PREV((ep1), link) = (lep); \
247 APR_RING_NEXT((epN), link) = APR_RING_NEXT((lep), link); \
248 APR_RING_PREV(APR_RING_NEXT((lep), link), link) = (epN); \
249 APR_RING_NEXT((lep), link) = (ep1); \
250 } while (0)
251
261#define APR_RING_INSERT_BEFORE(lep, nep, link) \
262 APR_RING_SPLICE_BEFORE((lep), (nep), (nep), link)
263
273#define APR_RING_INSERT_AFTER(lep, nep, link) \
274 APR_RING_SPLICE_AFTER((lep), (nep), (nep), link)
275
276
286#define APR_RING_SPLICE_HEAD(hp, ep1, epN, elem, link) do { \
287 APR_RING_PREV((ep1), link) = APR_RING_SENTINEL((hp), elem, link);\
288 APR_RING_NEXT((epN), link) = APR_RING_FIRST((hp)); \
289 APR_RING_PREV(APR_RING_FIRST((hp)), link) = (epN); \
290 APR_RING_FIRST((hp)) = (ep1); \
291 } while (0)
292
302#define APR_RING_SPLICE_TAIL(hp, ep1, epN, elem, link) do { \
303 APR_RING_NEXT((epN), link) = APR_RING_SENTINEL((hp), elem, link);\
304 APR_RING_PREV((ep1), link) = APR_RING_LAST((hp)); \
305 APR_RING_NEXT(APR_RING_LAST((hp)), link) = (ep1); \
306 APR_RING_LAST((hp)) = (epN); \
307 } while (0)
308
317#define APR_RING_INSERT_HEAD(hp, nep, elem, link) \
318 APR_RING_SPLICE_HEAD((hp), (nep), (nep), elem, link)
319
328#define APR_RING_INSERT_TAIL(hp, nep, elem, link) \
329 APR_RING_SPLICE_TAIL((hp), (nep), (nep), elem, link)
330
338#define APR_RING_CONCAT(h1, h2, elem, link) do { \
339 if (!APR_RING_EMPTY((h2), elem, link)) { \
340 APR_RING_SPLICE_TAIL((h1), APR_RING_FIRST((h2)), \
341 APR_RING_LAST((h2)), elem, link); \
342 APR_RING_INIT((h2), elem, link); \
343 } \
344 } while (0)
345
353#define APR_RING_PREPEND(h1, h2, elem, link) do { \
354 if (!APR_RING_EMPTY((h2), elem, link)) { \
355 APR_RING_SPLICE_HEAD((h1), APR_RING_FIRST((h2)), \
356 APR_RING_LAST((h2)), elem, link); \
357 APR_RING_INIT((h2), elem, link); \
358 } \
359 } while (0)
360
368#define APR_RING_UNSPLICE(ep1, epN, link) do { \
369 APR_RING_NEXT(APR_RING_PREV((ep1), link), link) = \
370 APR_RING_NEXT((epN), link); \
371 APR_RING_PREV(APR_RING_NEXT((epN), link), link) = \
372 APR_RING_PREV((ep1), link); \
373 } while (0)
374
381#define APR_RING_REMOVE(ep, link) \
382 APR_RING_UNSPLICE((ep), (ep), link)
383
391#define APR_RING_FOREACH(ep, head, elem, link) \
392 for (ep = APR_RING_FIRST(head); \
393 ep != APR_RING_SENTINEL(head, elem, link); \
394 ep = APR_RING_NEXT(ep, link))
395
404#define APR_RING_FOREACH_SAFE(ep1, ep2, head, elem, link) \
405 for (ep1 = APR_RING_FIRST(head), ep2 = APR_RING_NEXT(ep1, link); \
406 ep1 != APR_RING_SENTINEL(head, elem, link); \
407 ep1 = ep2, ep2 = APR_RING_NEXT(ep1, link))
408
409/* Debugging tools: */
410
411#ifdef APR_RING_DEBUG
412#include <stdio.h>
413#include <assert.h>
414
415#define APR_RING_CHECK_ONE(msg, ptr) \
416 fprintf(stderr, "*** %s %p\n", msg, ptr)
417
418#define APR_RING_CHECK(hp, elem, link, msg) \
419 APR_RING_CHECK_ELEM(APR_RING_SENTINEL(hp, elem, link), elem, link, msg)
420
421#define APR_RING_CHECK_ELEM(ep, elem, link, msg) do { \
422 struct elem *start = (ep); \
423 struct elem *here = start; \
424 fprintf(stderr, "*** ring check start -- %s\n", msg); \
425 do { \
426 fprintf(stderr, "\telem %p\n", here); \
427 fprintf(stderr, "\telem->next %p\n", \
428 APR_RING_NEXT(here, link)); \
429 fprintf(stderr, "\telem->prev %p\n", \
430 APR_RING_PREV(here, link)); \
431 fprintf(stderr, "\telem->next->prev %p\n", \
432 APR_RING_PREV(APR_RING_NEXT(here, link), link)); \
433 fprintf(stderr, "\telem->prev->next %p\n", \
434 APR_RING_NEXT(APR_RING_PREV(here, link), link)); \
435 if (APR_RING_PREV(APR_RING_NEXT(here, link), link) != here) { \
436 fprintf(stderr, "\t*** elem->next->prev != elem\n"); \
437 break; \
438 } \
439 if (APR_RING_NEXT(APR_RING_PREV(here, link), link) != here) { \
440 fprintf(stderr, "\t*** elem->prev->next != elem\n"); \
441 break; \
442 } \
443 here = APR_RING_NEXT(here, link); \
444 } while (here != start); \
445 fprintf(stderr, "*** ring check end\n"); \
446 } while (0)
447
448#define APR_RING_CHECK_CONSISTENCY(hp, elem, link) \
449 APR_RING_CHECK_ELEM_CONSISTENCY(APR_RING_SENTINEL(hp, elem, link),\
450 elem, link)
451
452#define APR_RING_CHECK_ELEM_CONSISTENCY(ep, elem, link) do { \
453 struct elem *start = (ep); \
454 struct elem *here = start; \
455 do { \
456 assert(APR_RING_PREV(APR_RING_NEXT(here, link), link) == here); \
457 assert(APR_RING_NEXT(APR_RING_PREV(here, link), link) == here); \
458 here = APR_RING_NEXT(here, link); \
459 } while (here != start); \
460 } while (0)
461
462#else
469#define APR_RING_CHECK_ONE(msg, ptr)
480#define APR_RING_CHECK(hp, elem, link, msg)
490#define APR_RING_CHECK_CONSISTENCY(hp, elem, link)
501#define APR_RING_CHECK_ELEM(ep, elem, link, msg)
512#define APR_RING_CHECK_ELEM_CONSISTENCY(ep, elem, link)
513#endif
514
517#endif /* !APR_RING_H */
apr_general.h
APR Miscellaneous library routines.
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