source: rtems/cpukit/libnetworking/sys/queue.h @ 39e6e65a

4.104.114.84.95
Last change on this file since 39e6e65a was 39e6e65a, checked in by Joel Sherrill <joel.sherrill@…>, on Aug 19, 1998 at 9:32:28 PM

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1/*
2 * Copyright (c) 1991, 1993
3 *      The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by the University of
16 *      California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *      @(#)queue.h     8.5 (Berkeley) 8/20/94
34 * $Id$
35 */
36
37#ifndef _SYS_QUEUE_H_
38#define _SYS_QUEUE_H_
39
40/*
41 * This file defines five types of data structures: singly-linked lists,
42 * slingly-linked tail queues, lists, tail queues, and circular queues.
43 *
44 * A singly-linked list is headed by a single forward pointer. The elements
45 * are singly linked for minimum space and pointer manipulation overhead at
46 * the expense of O(n) removal for arbitrary elements. New elements can be
47 * added to the list after an existing element or at the head of the list.
48 * Elements being removed from the head of the list should use the explicit
49 * macro for this purpose for optimum efficiency. A singly-linked list may
50 * only be traversed in the forward direction.  Singly-linked lists are ideal
51 * for applications with large datasets and few or no removals or for
52 * implementing a LIFO queue.
53 *
54 * A singly-linked tail queue is headed by a pair of pointers, one to the
55 * head of the list and the other to the tail of the list. The elements are
56 * singly linked for minimum space and pointer manipulation overhead at the
57 * expense of O(n) removal for arbitrary elements. New elements can be added
58 * to the list after an existing element, at the head of the list, or at the
59 * end of the list. Elements being removed from the head of the tail queue
60 * should use the explicit macro for this purpose for optimum efficiency.
61 * A singly-linked tail queue may only be traversed in the forward direction.
62 * Singly-linked tail queues are ideal for applications with large datasets
63 * and few or no removals or for implementing a FIFO queue.
64 *
65 * A list is headed by a single forward pointer (or an array of forward
66 * pointers for a hash table header). The elements are doubly linked
67 * so that an arbitrary element can be removed without a need to
68 * traverse the list. New elements can be added to the list before
69 * or after an existing element or at the head of the list. A list
70 * may only be traversed in the forward direction.
71 *
72 * A tail queue is headed by a pair of pointers, one to the head of the
73 * list and the other to the tail of the list. The elements are doubly
74 * linked so that an arbitrary element can be removed without a need to
75 * traverse the list. New elements can be added to the list before or
76 * after an existing element, at the head of the list, or at the end of
77 * the list. A tail queue may only be traversed in the forward direction.
78 *
79 * A circle queue is headed by a pair of pointers, one to the head of the
80 * list and the other to the tail of the list. The elements are doubly
81 * linked so that an arbitrary element can be removed without a need to
82 * traverse the list. New elements can be added to the list before or after
83 * an existing element, at the head of the list, or at the end of the list.
84 * A circle queue may be traversed in either direction, but has a more
85 * complex end of list detection.
86 *
87 * For details on the use of these macros, see the queue(3) manual page.
88 */
89
90/*
91 * Singly-linked List definitions.
92 */
93#define SLIST_HEAD(name, type)                                          \
94struct name {                                                           \
95        struct type *slh_first; /* first element */                     \
96}
97 
98#define SLIST_ENTRY(type)                                               \
99struct {                                                                \
100        struct type *sle_next;  /* next element */                      \
101}
102 
103/*
104 * Singly-linked List functions.
105 */
106#define SLIST_INIT(head) {                                              \
107        (head)->slh_first = NULL;                                       \
108}
109
110#define SLIST_INSERT_AFTER(slistelm, elm, field) {                      \
111        (elm)->field.sle_next = (slistelm)->field.sle_next;             \
112        (slistelm)->field.sle_next = (elm);                             \
113}
114
115#define SLIST_INSERT_HEAD(head, elm, field) {                           \
116        (elm)->field.sle_next = (head)->slh_first;                      \
117        (head)->slh_first = (elm);                                      \
118}
119
120#define SLIST_REMOVE_HEAD(head, field) {                                \
121        (head)->slh_first = (head)->slh_first->field.sle_next;          \
122}
123
124#define SLIST_REMOVE(head, elm, type, field) {                          \
125        if ((head)->slh_first == (elm)) {                               \
126                SLIST_REMOVE_HEAD((head), field);                       \
127        }                                                               \
128        else {                                                          \
129                struct type *curelm = (head)->slh_first;                \
130                while( curelm->field.sle_next != (elm) )                \
131                        curelm = curelm->field.sle_next;                \
132                curelm->field.sle_next =                                \
133                    curelm->field.sle_next->field.sle_next;             \
134        }                                                               \
135}
136
137/*
138 * Singly-linked Tail queue definitions.
139 */
140#define STAILQ_HEAD(name, type)                                         \
141struct name {                                                           \
142        struct type *stqh_first;/* first element */                     \
143        struct type **stqh_last;/* addr of last next element */         \
144}
145
146#define STAILQ_ENTRY(type)                                              \
147struct {                                                                \
148        struct type *stqe_next; /* next element */                      \
149}
150
151/*
152 * Singly-linked Tail queue functions.
153 */
154#define STAILQ_INIT(head) {                                             \
155        (head)->stqh_first = NULL;                                      \
156        (head)->stqh_last = &(head)->stqh_first;                        \
157}
158
159#define STAILQ_INSERT_HEAD(head, elm, field) {                          \
160        if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
161                (head)->stqh_last = &(elm)->field.stqe_next;            \
162        (head)->stqh_first = (elm);                                     \
163}
164
165#define STAILQ_INSERT_TAIL(head, elm, field) {                          \
166        (elm)->field.stqe_next = NULL;                                  \
167        *(head)->stqh_last = (elm);                                     \
168        (head)->stqh_last = &(elm)->field.stqe_next;                    \
169}
170
171#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) {                  \
172        if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
173                (head)->stqh_last = &(elm)->field.stqe_next;            \
174        (tqelm)->field.stqe_next = (elm);                               \
175}
176
177#define STAILQ_REMOVE_HEAD(head, field) {                               \
178        if (((head)->stqh_first =                                       \
179             (head)->stqh_first->field.stqe_next) == NULL)              \
180                (head)->stqh_last = &(head)->stqh_first;                \
181}
182
183#define STAILQ_REMOVE(head, elm, type, field) {                         \
184        if ((head)->stqh_first == (elm)) {                              \
185                STAILQ_REMOVE_HEAD(head, field);                        \
186        }                                                               \
187        else {                                                          \
188                struct type *curelm = (head)->stqh_first;               \
189                while( curelm->field.stqe_next != (elm) )               \
190                        curelm = curelm->field.stqe_next;               \
191                if((curelm->field.stqe_next =                           \
192                    curelm->field.stqe_next->field.stqe_next) == NULL)  \
193                        (head)->stqh_last = &(curelm)->field.stqe_next; \
194        }                                                               \
195}
196
197/*
198 * List definitions.
199 */
200#define LIST_HEAD(name, type)                                           \
201struct name {                                                           \
202        struct type *lh_first;  /* first element */                     \
203}
204
205#define LIST_ENTRY(type)                                                \
206struct {                                                                \
207        struct type *le_next;   /* next element */                      \
208        struct type **le_prev;  /* address of previous next element */  \
209}
210
211/*
212 * List functions.
213 */
214#define LIST_INIT(head) {                                               \
215        (head)->lh_first = NULL;                                        \
216}
217
218#define LIST_INSERT_AFTER(listelm, elm, field) {                        \
219        if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
220                (listelm)->field.le_next->field.le_prev =               \
221                    &(elm)->field.le_next;                              \
222        (listelm)->field.le_next = (elm);                               \
223        (elm)->field.le_prev = &(listelm)->field.le_next;               \
224}
225
226#define LIST_INSERT_BEFORE(listelm, elm, field) {                       \
227        (elm)->field.le_prev = (listelm)->field.le_prev;                \
228        (elm)->field.le_next = (listelm);                               \
229        *(listelm)->field.le_prev = (elm);                              \
230        (listelm)->field.le_prev = &(elm)->field.le_next;               \
231}
232
233#define LIST_INSERT_HEAD(head, elm, field) {                            \
234        if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
235                (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
236        (head)->lh_first = (elm);                                       \
237        (elm)->field.le_prev = &(head)->lh_first;                       \
238}
239
240#define LIST_REMOVE(elm, field) {                                       \
241        if ((elm)->field.le_next != NULL)                               \
242                (elm)->field.le_next->field.le_prev =                   \
243                    (elm)->field.le_prev;                               \
244        *(elm)->field.le_prev = (elm)->field.le_next;                   \
245}
246
247/*
248 * Tail queue definitions.
249 */
250#define TAILQ_HEAD(name, type)                                          \
251struct name {                                                           \
252        struct type *tqh_first; /* first element */                     \
253        struct type **tqh_last; /* addr of last next element */         \
254}
255
256#define TAILQ_HEAD_INITIALIZER(head)                                    \
257        { NULL, &(head).tqh_first }
258
259#define TAILQ_ENTRY(type)                                               \
260struct {                                                                \
261        struct type *tqe_next;  /* next element */                      \
262        struct type **tqe_prev; /* address of previous next element */  \
263}
264
265/*
266 * Tail queue functions.
267 */
268#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
269
270#define TAILQ_FIRST(head) ((head)->tqh_first)
271
272#define TAILQ_LAST(head) ((head)->tqh_last)
273
274#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
275
276#define TAILQ_PREV(elm, field) ((elm)->field.tqe_prev)
277
278#define TAILQ_INIT(head) {                                              \
279        (head)->tqh_first = NULL;                                       \
280        (head)->tqh_last = &(head)->tqh_first;                          \
281}
282
283#define TAILQ_INSERT_HEAD(head, elm, field) {                           \
284        if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
285                (head)->tqh_first->field.tqe_prev =                     \
286                    &(elm)->field.tqe_next;                             \
287        else                                                            \
288                (head)->tqh_last = &(elm)->field.tqe_next;              \
289        (head)->tqh_first = (elm);                                      \
290        (elm)->field.tqe_prev = &(head)->tqh_first;                     \
291}
292
293#define TAILQ_INSERT_TAIL(head, elm, field) {                           \
294        (elm)->field.tqe_next = NULL;                                   \
295        (elm)->field.tqe_prev = (head)->tqh_last;                       \
296        *(head)->tqh_last = (elm);                                      \
297        (head)->tqh_last = &(elm)->field.tqe_next;                      \
298}
299
300#define TAILQ_INSERT_AFTER(head, listelm, elm, field) {                 \
301        if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
302                (elm)->field.tqe_next->field.tqe_prev =                 \
303                    &(elm)->field.tqe_next;                             \
304        else                                                            \
305                (head)->tqh_last = &(elm)->field.tqe_next;              \
306        (listelm)->field.tqe_next = (elm);                              \
307        (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
308}
309
310#define TAILQ_INSERT_BEFORE(listelm, elm, field) {                      \
311        (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
312        (elm)->field.tqe_next = (listelm);                              \
313        *(listelm)->field.tqe_prev = (elm);                             \
314        (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
315}
316
317#define TAILQ_REMOVE(head, elm, field) {                                \
318        if (((elm)->field.tqe_next) != NULL)                            \
319                (elm)->field.tqe_next->field.tqe_prev =                 \
320                    (elm)->field.tqe_prev;                              \
321        else                                                            \
322                (head)->tqh_last = (elm)->field.tqe_prev;               \
323        *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
324}
325
326/*
327 * Circular queue definitions.
328 */
329#define CIRCLEQ_HEAD(name, type)                                        \
330struct name {                                                           \
331        struct type *cqh_first;         /* first element */             \
332        struct type *cqh_last;          /* last element */              \
333}
334
335#define CIRCLEQ_ENTRY(type)                                             \
336struct {                                                                \
337        struct type *cqe_next;          /* next element */              \
338        struct type *cqe_prev;          /* previous element */          \
339}
340
341/*
342 * Circular queue functions.
343 */
344#define CIRCLEQ_INIT(head) {                                            \
345        (head)->cqh_first = (void *)(head);                             \
346        (head)->cqh_last = (void *)(head);                              \
347}
348
349#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) {               \
350        (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
351        (elm)->field.cqe_prev = (listelm);                              \
352        if ((listelm)->field.cqe_next == (void *)(head))                \
353                (head)->cqh_last = (elm);                               \
354        else                                                            \
355                (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
356        (listelm)->field.cqe_next = (elm);                              \
357}
358
359#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) {              \
360        (elm)->field.cqe_next = (listelm);                              \
361        (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
362        if ((listelm)->field.cqe_prev == (void *)(head))                \
363                (head)->cqh_first = (elm);                              \
364        else                                                            \
365                (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
366        (listelm)->field.cqe_prev = (elm);                              \
367}
368
369#define CIRCLEQ_INSERT_HEAD(head, elm, field) {                         \
370        (elm)->field.cqe_next = (head)->cqh_first;                      \
371        (elm)->field.cqe_prev = (void *)(head);                         \
372        if ((head)->cqh_last == (void *)(head))                         \
373                (head)->cqh_last = (elm);                               \
374        else                                                            \
375                (head)->cqh_first->field.cqe_prev = (elm);              \
376        (head)->cqh_first = (elm);                                      \
377}
378
379#define CIRCLEQ_INSERT_TAIL(head, elm, field) {                         \
380        (elm)->field.cqe_next = (void *)(head);                         \
381        (elm)->field.cqe_prev = (head)->cqh_last;                       \
382        if ((head)->cqh_first == (void *)(head))                        \
383                (head)->cqh_first = (elm);                              \
384        else                                                            \
385                (head)->cqh_last->field.cqe_next = (elm);               \
386        (head)->cqh_last = (elm);                                       \
387}
388
389#define CIRCLEQ_REMOVE(head, elm, field) {                              \
390        if ((elm)->field.cqe_next == (void *)(head))                    \
391                (head)->cqh_last = (elm)->field.cqe_prev;               \
392        else                                                            \
393                (elm)->field.cqe_next->field.cqe_prev =                 \
394                    (elm)->field.cqe_prev;                              \
395        if ((elm)->field.cqe_prev == (void *)(head))                    \
396                (head)->cqh_first = (elm)->field.cqe_next;              \
397        else                                                            \
398                (elm)->field.cqe_prev->field.cqe_next =                 \
399                    (elm)->field.cqe_next;                              \
400}
401
402#ifdef KERNEL
403
404/*
405 * XXX insque() and remque() are an old way of handling certain queues.
406 * They bogusly assumes that all queue heads look alike.
407 */
408
409struct quehead {
410        struct quehead *qh_link;
411        struct quehead *qh_rlink;
412};
413
414#ifdef  __GNUC__
415
416static __inline void
417insque(void *a, void *b)
418{
419        struct quehead *element = a, *head = b;
420
421        element->qh_link = head->qh_link;
422        element->qh_rlink = head;
423        head->qh_link = element;
424        element->qh_link->qh_rlink = element;
425}
426
427static __inline void
428remque(void *a)
429{
430        struct quehead *element = a;
431
432        element->qh_link->qh_rlink = element->qh_rlink;
433        element->qh_rlink->qh_link = element->qh_link;
434        element->qh_rlink = 0;
435}
436
437#else /* !__GNUC__ */
438
439void    insque __P((void *a, void *b));
440void    remque __P((void *a));
441
442#endif /* __GNUC__ */
443
444#endif /* KERNEL */
445
446#endif /* !_SYS_QUEUE_H_ */
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