openssh/openbsd-compat/fake-queue.h

   1 /*      $OpenBSD: queue.h,v 1.16 2000/09/07 19:47:59 art Exp $  */
   2 /*      $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $       */
   3
   4 /*
   5  * Copyright (c) 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  37  */
  38
  39 #ifndef _SYS_QUEUE_H_
  40 #define _SYS_QUEUE_H_
  41
  42 /*
  43  * This file defines five types of data structures: singly-linked lists,
  44  * lists, simple queues, tail queues, and circular queues.
  45  *
  46  *
  47  * A singly-linked list is headed by a single forward pointer. The elements
  48  * are singly linked for minimum space and pointer manipulation overhead at
  49  * the expense of O(n) removal for arbitrary elements. New elements can be
  50  * added to the list after an existing element or at the head of the list.
  51  * Elements being removed from the head of the list should use the explicit
  52  * macro for this purpose for optimum efficiency. A singly-linked list may
  53  * only be traversed in the forward direction.  Singly-linked lists are ideal
  54  * for applications with large datasets and few or no removals or for
  55  * implementing a LIFO queue.
  56  *
  57  * A list is headed by a single forward pointer (or an array of forward
  58  * pointers for a hash table header). The elements are doubly linked
  59  * so that an arbitrary element can be removed without a need to
  60  * traverse the list. New elements can be added to the list before
  61  * or after an existing element or at the head of the list. A list
  62  * may only be traversed in the forward direction.
  63  *
  64  * A simple queue is headed by a pair of pointers, one the head of the
  65  * list and the other to the tail of the list. The elements are singly
  66  * linked to save space, so elements can only be removed from the
  67  * head of the list. New elements can be added to the list before or after
  68  * an existing element, at the head of the list, or at the end of the
  69  * list. A simple queue may only be traversed in the forward direction.
  70  *
  71  * A tail queue is headed by a pair of pointers, one to the head of the
  72  * list and the other to the tail of the list. The elements are doubly
  73  * linked so that an arbitrary element can be removed without a need to
  74  * traverse the list. New elements can be added to the list before or
  75  * after an existing element, at the head of the list, or at the end of
  76  * the list. A tail queue may be traversed in either direction.
  77  *
  78  * A circle queue is headed by a pair of pointers, one to the head of the
  79  * list and the other to the tail of the list. The elements are doubly
  80  * linked so that an arbitrary element can be removed without a need to
  81  * traverse the list. New elements can be added to the list before or after
  82  * an existing element, at the head of the list, or at the end of the list.
  83  * A circle queue may be traversed in either direction, but has a more
  84  * complex end of list detection.
  85  *
  86  * For details on the use of these macros, see the queue(3) manual page.
  87  */
  88
  89 /*
  90  * Singly-linked List definitions.
  91  */
  92 #define SLIST_HEAD(name, type)                                          \
  93 struct name {                                                           \
  94         struct type *slh_first; /* first element */                     \
  95 }
  96
  97 #define SLIST_HEAD_INITIALIZER(head)                                    \
  98         { NULL }
  99
 100 #define SLIST_ENTRY(type)                                               \
 101 struct {                                                                \
 102         struct type *sle_next;  /* next element */                      \
 103 }
 104
 105 /*
 106  * Singly-linked List access methods.
 107  */
 108 #define SLIST_FIRST(head)       ((head)->slh_first)
 109 #define SLIST_END(head)         NULL
 110 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 111 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 112
 113 #define SLIST_FOREACH(var, head, field)                                 \
 114         for((var) = SLIST_FIRST(head);                                  \
 115             (var) != SLIST_END(head);                                   \
 116             (var) = SLIST_NEXT(var, field))
 117
 118 /*
 119  * Singly-linked List functions.
 120  */
 121 #define SLIST_INIT(head) {                                              \
 122         SLIST_FIRST(head) = SLIST_END(head);                            \
 123 }
 124
 125 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 126         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 127         (slistelm)->field.sle_next = (elm);                             \
 128 } while (0)
 129
 130 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 131         (elm)->field.sle_next = (head)->slh_first;                      \
 132         (head)->slh_first = (elm);                                      \
 133 } while (0)
 134
 135 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 136         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 137 } while (0)
 138
 139 /*
 140  * List definitions.
 141  */
 142 #define LIST_HEAD(name, type)                                           \
 143 struct name {                                                           \
 144         struct type *lh_first;  /* first element */                     \
 145 }
 146
 147 #define LIST_HEAD_INITIALIZER(head)                                     \
 148         { NULL }
 149
 150 #define LIST_ENTRY(type)                                                \
 151 struct {                                                                \
 152         struct type *le_next;   /* next element */                      \
 153         struct type **le_prev;  /* address of previous next element */  \
 154 }
 155
 156 /*
 157  * List access methods
 158  */
 159 #define LIST_FIRST(head)                ((head)->lh_first)
 160 #define LIST_END(head)                  NULL
 161 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 162 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 163
 164 #define LIST_FOREACH(var, head, field)                                  \
 165         for((var) = LIST_FIRST(head);                                   \
 166             (var)!= LIST_END(head);                                     \
 167             (var) = LIST_NEXT(var, field))
 168
 169 /*
 170  * List functions.
 171  */
 172 #define LIST_INIT(head) do {                                            \
 173         LIST_FIRST(head) = LIST_END(head);                              \
 174 } while (0)
 175
 176 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 177         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 178                 (listelm)->field.le_next->field.le_prev =               \
 179                     &(elm)->field.le_next;                              \
 180         (listelm)->field.le_next = (elm);                               \
 181         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 182 } while (0)
 183
 184 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 185         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 186         (elm)->field.le_next = (listelm);                               \
 187         *(listelm)->field.le_prev = (elm);                              \
 188         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 189 } while (0)
 190
 191 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 192         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 193                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 194         (head)->lh_first = (elm);                                       \
 195         (elm)->field.le_prev = &(head)->lh_first;                       \
 196 } while (0)
 197
 198 #define LIST_REMOVE(elm, field) do {                                    \
 199         if ((elm)->field.le_next != NULL)                               \
 200                 (elm)->field.le_next->field.le_prev =                   \
 201                     (elm)->field.le_prev;                               \
 202         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 203 } while (0)
 204
 205 #define LIST_REPLACE(elm, elm2, field) do {                             \
 206         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 207                 (elm2)->field.le_next->field.le_prev =                  \
 208                     &(elm2)->field.le_next;                             \
 209         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 210         *(elm2)->field.le_prev = (elm2);                                \
 211 } while (0)
 212
 213 /*
 214  * Simple queue definitions.
 215  */
 216 #define SIMPLEQ_HEAD(name, type)                                        \
 217 struct name {                                                           \
 218         struct type *sqh_first; /* first element */                     \
 219         struct type **sqh_last; /* addr of last next element */         \
 220 }
 221
 222 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 223         { NULL, &(head).sqh_first }
 224
 225 #define SIMPLEQ_ENTRY(type)                                             \
 226 struct {                                                                \
 227         struct type *sqe_next;  /* next element */                      \
 228 }
 229
 230 /*
 231  * Simple queue access methods.
 232  */
 233 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 234 #define SIMPLEQ_END(head)           NULL
 235 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 236 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 237
 238 #define SIMPLEQ_FOREACH(var, head, field)                               \
 239         for((var) = SIMPLEQ_FIRST(head);                                \
 240             (var) != SIMPLEQ_END(head);                                 \
 241             (var) = SIMPLEQ_NEXT(var, field))
 242
 243 /*
 244  * Simple queue functions.
 245  */
 246 #define SIMPLEQ_INIT(head) do {                                         \
 247         (head)->sqh_first = NULL;                                       \
 248         (head)->sqh_last = &(head)->sqh_first;                          \
 249 } while (0)
 250
 251 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 252         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 253                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 254         (head)->sqh_first = (elm);                                      \
 255 } while (0)
 256
 257 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 258         (elm)->field.sqe_next = NULL;                                   \
 259         *(head)->sqh_last = (elm);                                      \
 260         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 261 } while (0)
 262
 263 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 264         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 265                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 266         (listelm)->field.sqe_next = (elm);                              \
 267 } while (0)
 268
 269 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {                      \
 270         if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)        \
 271                 (head)->sqh_last = &(head)->sqh_first;                  \
 272 } while (0)
 273
 274 /*
 275  * Tail queue definitions.
 276  */
 277 #define TAILQ_HEAD(name, type)                                          \
 278 struct name {                                                           \
 279         struct type *tqh_first; /* first element */                     \
 280         struct type **tqh_last; /* addr of last next element */         \
 281 }
 282
 283 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 284         { NULL, &(head).tqh_first }
 285
 286 #define TAILQ_ENTRY(type)                                               \
 287 struct {                                                                \
 288         struct type *tqe_next;  /* next element */                      \
 289         struct type **tqe_prev; /* address of previous next element */  \
 290 }
 291
 292 /*
 293  * tail queue access methods
 294  */
 295 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 296 #define TAILQ_END(head)                 NULL
 297 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 298 #define TAILQ_LAST(head, headname)                                      \
 299         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 300 /* XXX */
 301 #define TAILQ_PREV(elm, headname, field)                                \
 302         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 303 #define TAILQ_EMPTY(head)                                               \
 304         (TAILQ_FIRST(head) == TAILQ_END(head))
 305
 306 #define TAILQ_FOREACH(var, head, field)                                 \
 307         for((var) = TAILQ_FIRST(head);                                  \
 308             (var) != TAILQ_END(head);                                   \
 309             (var) = TAILQ_NEXT(var, field))
 310
 311 #define TAILQ_FOREACH_REVERSE(var, head, field, headname)               \
 312         for((var) = TAILQ_LAST(head, headname);                         \
 313             (var) != TAILQ_END(head);                                   \
 314             (var) = TAILQ_PREV(var, headname, field))
 315
 316 /*
 317  * Tail queue functions.
 318  */
 319 #define TAILQ_INIT(head) do {                                           \
 320         (head)->tqh_first = NULL;                                       \
 321         (head)->tqh_last = &(head)->tqh_first;                          \
 322 } while (0)
 323
 324 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 325         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 326                 (head)->tqh_first->field.tqe_prev =                     \
 327                     &(elm)->field.tqe_next;                             \
 328         else                                                            \
 329                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 330         (head)->tqh_first = (elm);                                      \
 331         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 332 } while (0)
 333
 334 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 335         (elm)->field.tqe_next = NULL;                                   \
 336         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 337         *(head)->tqh_last = (elm);                                      \
 338         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 339 } while (0)
 340
 341 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 342         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 343                 (elm)->field.tqe_next->field.tqe_prev =                 \
 344                     &(elm)->field.tqe_next;                             \
 345         else                                                            \
 346                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 347         (listelm)->field.tqe_next = (elm);                              \
 348         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 349 } while (0)
 350
 351 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 352         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 353         (elm)->field.tqe_next = (listelm);                              \
 354         *(listelm)->field.tqe_prev = (elm);                             \
 355         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 356 } while (0)
 357
 358 #define TAILQ_REMOVE(head, elm, field) do {                             \
 359         if (((elm)->field.tqe_next) != NULL)                            \
 360                 (elm)->field.tqe_next->field.tqe_prev =                 \
 361                     (elm)->field.tqe_prev;                              \
 362         else                                                            \
 363                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 364         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 365 } while (0)
 366
 367 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 368         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 369                 (elm2)->field.tqe_next->field.tqe_prev =                \
 370                     &(elm2)->field.tqe_next;                            \
 371         else                                                            \
 372                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 373         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 374         *(elm2)->field.tqe_prev = (elm2);                               \
 375 } while (0)
 376
 377 /*
 378  * Circular queue definitions.
 379  */
 380 #define CIRCLEQ_HEAD(name, type)                                        \
 381 struct name {                                                           \
 382         struct type *cqh_first;         /* first element */             \
 383         struct type *cqh_last;          /* last element */              \
 384 }
 385
 386 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 387         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 388
 389 #define CIRCLEQ_ENTRY(type)                                             \
 390 struct {                                                                \
 391         struct type *cqe_next;          /* next element */              \
 392         struct type *cqe_prev;          /* previous element */          \
 393 }
 394
 395 /*
 396  * Circular queue access methods
 397  */
 398 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 399 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 400 #define CIRCLEQ_END(head)               ((void *)(head))
 401 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 402 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 403 #define CIRCLEQ_EMPTY(head)                                             \
 404         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 405
 406 #define CIRCLEQ_FOREACH(var, head, field)                               \
 407         for((var) = CIRCLEQ_FIRST(head);                                \
 408             (var) != CIRCLEQ_END(head);                                 \
 409             (var) = CIRCLEQ_NEXT(var, field))
 410
 411 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 412         for((var) = CIRCLEQ_LAST(head);                                 \
 413             (var) != CIRCLEQ_END(head);                                 \
 414             (var) = CIRCLEQ_PREV(var, field))
 415
 416 /*
 417  * Circular queue functions.
 418  */
 419 #define CIRCLEQ_INIT(head) do {                                         \
 420         (head)->cqh_first = CIRCLEQ_END(head);                          \
 421         (head)->cqh_last = CIRCLEQ_END(head);                           \
 422 } while (0)
 423
 424 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 425         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 426         (elm)->field.cqe_prev = (listelm);                              \
 427         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 428                 (head)->cqh_last = (elm);                               \
 429         else                                                            \
 430                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 431         (listelm)->field.cqe_next = (elm);                              \
 432 } while (0)
 433
 434 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 435         (elm)->field.cqe_next = (listelm);                              \
 436         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 437         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 438                 (head)->cqh_first = (elm);                              \
 439         else                                                            \
 440                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 441         (listelm)->field.cqe_prev = (elm);                              \
 442 } while (0)
 443
 444 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 445         (elm)->field.cqe_next = (head)->cqh_first;                      \
 446         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 447         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 448                 (head)->cqh_last = (elm);                               \
 449         else                                                            \
 450                 (head)->cqh_first->field.cqe_prev = (elm);              \
 451         (head)->cqh_first = (elm);                                      \
 452 } while (0)
 453
 454 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 455         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 456         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 457         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 458                 (head)->cqh_first = (elm);                              \
 459         else                                                            \
 460                 (head)->cqh_last->field.cqe_next = (elm);               \
 461         (head)->cqh_last = (elm);                                       \
 462 } while (0)
 463
 464 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 465         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 466                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 467         else                                                            \
 468                 (elm)->field.cqe_next->field.cqe_prev =                 \
 469                     (elm)->field.cqe_prev;                              \
 470         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 471                 (head)->cqh_first = (elm)->field.cqe_next;              \
 472         else                                                            \
 473                 (elm)->field.cqe_prev->field.cqe_next =                 \
 474                     (elm)->field.cqe_next;                              \
 475 } while (0)
 476
 477 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 478         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 479             CIRCLEQ_END(head))                                          \
 480                 (head).cqh_last = (elm2);                               \
 481         else                                                            \
 482                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 483         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 484             CIRCLEQ_END(head))                                          \
 485                 (head).cqh_first = (elm2);                              \
 486         else                                                            \
 487                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 488 } while (0)
 489
 490 #endif  /* !_SYS_QUEUE_H_ */