crypto/openssh-3.9p1/openbsd-compat/sys-queue.h

   1 /* OPENBSD ORIGINAL: sys/sys/queue.h */
   2
   3 /*      $OpenBSD: queue.h,v 1.25 2004/04/08 16:08:21 henning Exp $      */
   4 /*      $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $       */
   5
   6 /*
   7  * Copyright (c) 1991, 1993
   8  *      The Regents of the University of California.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  35  */
  36
  37 #ifndef _FAKE_QUEUE_H_
  38 #define _FAKE_QUEUE_H_
  39
  40 /*
  41  * Require for OS/X and other platforms that have old/broken/incomplete
  42  * <sys/queue.h>.
  43  */
  44 #undef SLIST_HEAD
  45 #undef SLIST_HEAD_INITIALIZER
  46 #undef SLIST_ENTRY
  47 #undef SLIST_FOREACH_PREVPTR
  48 #undef SLIST_FIRST
  49 #undef SLIST_END
  50 #undef SLIST_EMPTY
  51 #undef SLIST_NEXT
  52 #undef SLIST_FOREACH
  53 #undef SLIST_INIT
  54 #undef SLIST_INSERT_AFTER
  55 #undef SLIST_INSERT_HEAD
  56 #undef SLIST_REMOVE_HEAD
  57 #undef SLIST_REMOVE
  58 #undef SLIST_REMOVE_NEXT
  59 #undef LIST_HEAD
  60 #undef LIST_HEAD_INITIALIZER
  61 #undef LIST_ENTRY
  62 #undef LIST_FIRST
  63 #undef LIST_END
  64 #undef LIST_EMPTY
  65 #undef LIST_NEXT
  66 #undef LIST_FOREACH
  67 #undef LIST_INIT
  68 #undef LIST_INSERT_AFTER
  69 #undef LIST_INSERT_BEFORE
  70 #undef LIST_INSERT_HEAD
  71 #undef LIST_REMOVE
  72 #undef LIST_REPLACE
  73 #undef SIMPLEQ_HEAD
  74 #undef SIMPLEQ_HEAD_INITIALIZER
  75 #undef SIMPLEQ_ENTRY
  76 #undef SIMPLEQ_FIRST
  77 #undef SIMPLEQ_END
  78 #undef SIMPLEQ_EMPTY
  79 #undef SIMPLEQ_NEXT
  80 #undef SIMPLEQ_FOREACH
  81 #undef SIMPLEQ_INIT
  82 #undef SIMPLEQ_INSERT_HEAD
  83 #undef SIMPLEQ_INSERT_TAIL
  84 #undef SIMPLEQ_INSERT_AFTER
  85 #undef SIMPLEQ_REMOVE_HEAD
  86 #undef TAILQ_HEAD
  87 #undef TAILQ_HEAD_INITIALIZER
  88 #undef TAILQ_ENTRY
  89 #undef TAILQ_FIRST
  90 #undef TAILQ_END
  91 #undef TAILQ_NEXT
  92 #undef TAILQ_LAST
  93 #undef TAILQ_PREV
  94 #undef TAILQ_EMPTY
  95 #undef TAILQ_FOREACH
  96 #undef TAILQ_FOREACH_REVERSE
  97 #undef TAILQ_INIT
  98 #undef TAILQ_INSERT_HEAD
  99 #undef TAILQ_INSERT_TAIL
 100 #undef TAILQ_INSERT_AFTER
 101 #undef TAILQ_INSERT_BEFORE
 102 #undef TAILQ_REMOVE
 103 #undef TAILQ_REPLACE
 104 #undef CIRCLEQ_HEAD
 105 #undef CIRCLEQ_HEAD_INITIALIZER
 106 #undef CIRCLEQ_ENTRY
 107 #undef CIRCLEQ_FIRST
 108 #undef CIRCLEQ_LAST
 109 #undef CIRCLEQ_END
 110 #undef CIRCLEQ_NEXT
 111 #undef CIRCLEQ_PREV
 112 #undef CIRCLEQ_EMPTY
 113 #undef CIRCLEQ_FOREACH
 114 #undef CIRCLEQ_FOREACH_REVERSE
 115 #undef CIRCLEQ_INIT
 116 #undef CIRCLEQ_INSERT_AFTER
 117 #undef CIRCLEQ_INSERT_BEFORE
 118 #undef CIRCLEQ_INSERT_HEAD
 119 #undef CIRCLEQ_INSERT_TAIL
 120 #undef CIRCLEQ_REMOVE
 121 #undef CIRCLEQ_REPLACE
 122
 123 /*
 124  * This file defines five types of data structures: singly-linked lists,
 125  * lists, simple queues, tail queues, and circular queues.
 126  *
 127  *
 128  * A singly-linked list is headed by a single forward pointer. The elements
 129  * are singly linked for minimum space and pointer manipulation overhead at
 130  * the expense of O(n) removal for arbitrary elements. New elements can be
 131  * added to the list after an existing element or at the head of the list.
 132  * Elements being removed from the head of the list should use the explicit
 133  * macro for this purpose for optimum efficiency. A singly-linked list may
 134  * only be traversed in the forward direction.  Singly-linked lists are ideal
 135  * for applications with large datasets and few or no removals or for
 136  * implementing a LIFO queue.
 137  *
 138  * A list is headed by a single forward pointer (or an array of forward
 139  * pointers for a hash table header). The elements are doubly linked
 140  * so that an arbitrary element can be removed without a need to
 141  * traverse the list. New elements can be added to the list before
 142  * or after an existing element or at the head of the list. A list
 143  * may only be traversed in the forward direction.
 144  *
 145  * A simple queue is headed by a pair of pointers, one the head of the
 146  * list and the other to the tail of the list. The elements are singly
 147  * linked to save space, so elements can only be removed from the
 148  * head of the list. New elements can be added to the list before or after
 149  * an existing element, at the head of the list, or at the end of the
 150  * list. A simple queue may only be traversed in the forward direction.
 151  *
 152  * A tail queue is headed by a pair of pointers, one to the head of the
 153  * list and the other to the tail of the list. The elements are doubly
 154  * linked so that an arbitrary element can be removed without a need to
 155  * traverse the list. New elements can be added to the list before or
 156  * after an existing element, at the head of the list, or at the end of
 157  * the list. A tail queue may be traversed in either direction.
 158  *
 159  * A circle queue is headed by a pair of pointers, one to the head of the
 160  * list and the other to the tail of the list. The elements are doubly
 161  * linked so that an arbitrary element can be removed without a need to
 162  * traverse the list. New elements can be added to the list before or after
 163  * an existing element, at the head of the list, or at the end of the list.
 164  * A circle queue may be traversed in either direction, but has a more
 165  * complex end of list detection.
 166  *
 167  * For details on the use of these macros, see the queue(3) manual page.
 168  */
 169
 170 /*
 171  * Singly-linked List definitions.
 172  */
 173 #define SLIST_HEAD(name, type)                                          \
 174 struct name {                                                           \
 175         struct type *slh_first; /* first element */                     \
 176 }
 177
 178 #define SLIST_HEAD_INITIALIZER(head)                                    \
 179         { NULL }
 180
 181 #define SLIST_ENTRY(type)                                               \
 182 struct {                                                                \
 183         struct type *sle_next;  /* next element */                      \
 184 }
 185
 186 /*
 187  * Singly-linked List access methods.
 188  */
 189 #define SLIST_FIRST(head)       ((head)->slh_first)
 190 #define SLIST_END(head)         NULL
 191 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 192 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 193
 194 #define SLIST_FOREACH(var, head, field)                                 \
 195         for((var) = SLIST_FIRST(head);                                  \
 196             (var) != SLIST_END(head);                                   \
 197             (var) = SLIST_NEXT(var, field))
 198
 199 #define SLIST_FOREACH_PREVPTR(var, varp, head, field)                   \
 200         for ((varp) = &SLIST_FIRST((head));                             \
 201             ((var) = *(varp)) != SLIST_END(head);                       \
 202             (varp) = &SLIST_NEXT((var), field))
 203
 204 /*
 205  * Singly-linked List functions.
 206  */
 207 #define SLIST_INIT(head) {                                              \
 208         SLIST_FIRST(head) = SLIST_END(head);                            \
 209 }
 210
 211 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 212         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 213         (slistelm)->field.sle_next = (elm);                             \
 214 } while (0)
 215
 216 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 217         (elm)->field.sle_next = (head)->slh_first;                      \
 218         (head)->slh_first = (elm);                                      \
 219 } while (0)
 220
 221 #define SLIST_REMOVE_NEXT(head, elm, field) do {                        \
 222         (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;  \
 223 } while (0)
 224
 225 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 226         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 227 } while (0)
 228
 229 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 230         if ((head)->slh_first == (elm)) {                               \
 231                 SLIST_REMOVE_HEAD((head), field);                       \
 232         }                                                               \
 233         else {                                                          \
 234                 struct type *curelm = (head)->slh_first;                \
 235                 while( curelm->field.sle_next != (elm) )                \
 236                         curelm = curelm->field.sle_next;                \
 237                 curelm->field.sle_next =                                \
 238                     curelm->field.sle_next->field.sle_next;             \
 239         }                                                               \
 240 } while (0)
 241
 242 /*
 243  * List definitions.
 244  */
 245 #define LIST_HEAD(name, type)                                           \
 246 struct name {                                                           \
 247         struct type *lh_first;  /* first element */                     \
 248 }
 249
 250 #define LIST_HEAD_INITIALIZER(head)                                     \
 251         { NULL }
 252
 253 #define LIST_ENTRY(type)                                                \
 254 struct {                                                                \
 255         struct type *le_next;   /* next element */                      \
 256         struct type **le_prev;  /* address of previous next element */  \
 257 }
 258
 259 /*
 260  * List access methods
 261  */
 262 #define LIST_FIRST(head)                ((head)->lh_first)
 263 #define LIST_END(head)                  NULL
 264 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 265 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 266
 267 #define LIST_FOREACH(var, head, field)                                  \
 268         for((var) = LIST_FIRST(head);                                   \
 269             (var)!= LIST_END(head);                                     \
 270             (var) = LIST_NEXT(var, field))
 271
 272 /*
 273  * List functions.
 274  */
 275 #define LIST_INIT(head) do {                                            \
 276         LIST_FIRST(head) = LIST_END(head);                              \
 277 } while (0)
 278
 279 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 280         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 281                 (listelm)->field.le_next->field.le_prev =               \
 282                     &(elm)->field.le_next;                              \
 283         (listelm)->field.le_next = (elm);                               \
 284         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 285 } while (0)
 286
 287 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 288         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 289         (elm)->field.le_next = (listelm);                               \
 290         *(listelm)->field.le_prev = (elm);                              \
 291         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 292 } while (0)
 293
 294 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 295         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 296                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 297         (head)->lh_first = (elm);                                       \
 298         (elm)->field.le_prev = &(head)->lh_first;                       \
 299 } while (0)
 300
 301 #define LIST_REMOVE(elm, field) do {                                    \
 302         if ((elm)->field.le_next != NULL)                               \
 303                 (elm)->field.le_next->field.le_prev =                   \
 304                     (elm)->field.le_prev;                               \
 305         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 306 } while (0)
 307
 308 #define LIST_REPLACE(elm, elm2, field) do {                             \
 309         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 310                 (elm2)->field.le_next->field.le_prev =                  \
 311                     &(elm2)->field.le_next;                             \
 312         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 313         *(elm2)->field.le_prev = (elm2);                                \
 314 } while (0)
 315
 316 /*
 317  * Simple queue definitions.
 318  */
 319 #define SIMPLEQ_HEAD(name, type)                                        \
 320 struct name {                                                           \
 321         struct type *sqh_first; /* first element */                     \
 322         struct type **sqh_last; /* addr of last next element */         \
 323 }
 324
 325 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 326         { NULL, &(head).sqh_first }
 327
 328 #define SIMPLEQ_ENTRY(type)                                             \
 329 struct {                                                                \
 330         struct type *sqe_next;  /* next element */                      \
 331 }
 332
 333 /*
 334  * Simple queue access methods.
 335  */
 336 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 337 #define SIMPLEQ_END(head)           NULL
 338 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 339 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 340
 341 #define SIMPLEQ_FOREACH(var, head, field)                               \
 342         for((var) = SIMPLEQ_FIRST(head);                                \
 343             (var) != SIMPLEQ_END(head);                                 \
 344             (var) = SIMPLEQ_NEXT(var, field))
 345
 346 /*
 347  * Simple queue functions.
 348  */
 349 #define SIMPLEQ_INIT(head) do {                                         \
 350         (head)->sqh_first = NULL;                                       \
 351         (head)->sqh_last = &(head)->sqh_first;                          \
 352 } while (0)
 353
 354 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 355         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 356                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 357         (head)->sqh_first = (elm);                                      \
 358 } while (0)
 359
 360 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 361         (elm)->field.sqe_next = NULL;                                   \
 362         *(head)->sqh_last = (elm);                                      \
 363         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 364 } while (0)
 365
 366 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 367         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 368                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 369         (listelm)->field.sqe_next = (elm);                              \
 370 } while (0)
 371
 372 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {                      \
 373         if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)        \
 374                 (head)->sqh_last = &(head)->sqh_first;                  \
 375 } while (0)
 376
 377 /*
 378  * Tail queue definitions.
 379  */
 380 #define TAILQ_HEAD(name, type)                                          \
 381 struct name {                                                           \
 382         struct type *tqh_first; /* first element */                     \
 383         struct type **tqh_last; /* addr of last next element */         \
 384 }
 385
 386 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 387         { NULL, &(head).tqh_first }
 388
 389 #define TAILQ_ENTRY(type)                                               \
 390 struct {                                                                \
 391         struct type *tqe_next;  /* next element */                      \
 392         struct type **tqe_prev; /* address of previous next element */  \
 393 }
 394
 395 /*
 396  * tail queue access methods
 397  */
 398 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 399 #define TAILQ_END(head)                 NULL
 400 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 401 #define TAILQ_LAST(head, headname)                                      \
 402         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 403 /* XXX */
 404 #define TAILQ_PREV(elm, headname, field)                                \
 405         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 406 #define TAILQ_EMPTY(head)                                               \
 407         (TAILQ_FIRST(head) == TAILQ_END(head))
 408
 409 #define TAILQ_FOREACH(var, head, field)                                 \
 410         for((var) = TAILQ_FIRST(head);                                  \
 411             (var) != TAILQ_END(head);                                   \
 412             (var) = TAILQ_NEXT(var, field))
 413
 414 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 415         for((var) = TAILQ_LAST(head, headname);                         \
 416             (var) != TAILQ_END(head);                                   \
 417             (var) = TAILQ_PREV(var, headname, field))
 418
 419 /*
 420  * Tail queue functions.
 421  */
 422 #define TAILQ_INIT(head) do {                                           \
 423         (head)->tqh_first = NULL;                                       \
 424         (head)->tqh_last = &(head)->tqh_first;                          \
 425 } while (0)
 426
 427 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 428         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 429                 (head)->tqh_first->field.tqe_prev =                     \
 430                     &(elm)->field.tqe_next;                             \
 431         else                                                            \
 432                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 433         (head)->tqh_first = (elm);                                      \
 434         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 435 } while (0)
 436
 437 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 438         (elm)->field.tqe_next = NULL;                                   \
 439         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 440         *(head)->tqh_last = (elm);                                      \
 441         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 442 } while (0)
 443
 444 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 445         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 446                 (elm)->field.tqe_next->field.tqe_prev =                 \
 447                     &(elm)->field.tqe_next;                             \
 448         else                                                            \
 449                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 450         (listelm)->field.tqe_next = (elm);                              \
 451         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 452 } while (0)
 453
 454 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 455         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 456         (elm)->field.tqe_next = (listelm);                              \
 457         *(listelm)->field.tqe_prev = (elm);                             \
 458         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 459 } while (0)
 460
 461 #define TAILQ_REMOVE(head, elm, field) do {                             \
 462         if (((elm)->field.tqe_next) != NULL)                            \
 463                 (elm)->field.tqe_next->field.tqe_prev =                 \
 464                     (elm)->field.tqe_prev;                              \
 465         else                                                            \
 466                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 467         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 468 } while (0)
 469
 470 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 471         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 472                 (elm2)->field.tqe_next->field.tqe_prev =                \
 473                     &(elm2)->field.tqe_next;                            \
 474         else                                                            \
 475                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 476         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 477         *(elm2)->field.tqe_prev = (elm2);                               \
 478 } while (0)
 479
 480 /*
 481  * Circular queue definitions.
 482  */
 483 #define CIRCLEQ_HEAD(name, type)                                        \
 484 struct name {                                                           \
 485         struct type *cqh_first;         /* first element */             \
 486         struct type *cqh_last;          /* last element */              \
 487 }
 488
 489 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 490         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 491
 492 #define CIRCLEQ_ENTRY(type)                                             \
 493 struct {                                                                \
 494         struct type *cqe_next;          /* next element */              \
 495         struct type *cqe_prev;          /* previous element */          \
 496 }
 497
 498 /*
 499  * Circular queue access methods
 500  */
 501 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 502 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 503 #define CIRCLEQ_END(head)               ((void *)(head))
 504 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 505 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 506 #define CIRCLEQ_EMPTY(head)                                             \
 507         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 508
 509 #define CIRCLEQ_FOREACH(var, head, field)                               \
 510         for((var) = CIRCLEQ_FIRST(head);                                \
 511             (var) != CIRCLEQ_END(head);                                 \
 512             (var) = CIRCLEQ_NEXT(var, field))
 513
 514 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 515         for((var) = CIRCLEQ_LAST(head);                                 \
 516             (var) != CIRCLEQ_END(head);                                 \
 517             (var) = CIRCLEQ_PREV(var, field))
 518
 519 /*
 520  * Circular queue functions.
 521  */
 522 #define CIRCLEQ_INIT(head) do {                                         \
 523         (head)->cqh_first = CIRCLEQ_END(head);                          \
 524         (head)->cqh_last = CIRCLEQ_END(head);                           \
 525 } while (0)
 526
 527 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 528         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 529         (elm)->field.cqe_prev = (listelm);                              \
 530         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 531                 (head)->cqh_last = (elm);                               \
 532         else                                                            \
 533                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 534         (listelm)->field.cqe_next = (elm);                              \
 535 } while (0)
 536
 537 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 538         (elm)->field.cqe_next = (listelm);                              \
 539         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 540         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 541                 (head)->cqh_first = (elm);                              \
 542         else                                                            \
 543                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 544         (listelm)->field.cqe_prev = (elm);                              \
 545 } while (0)
 546
 547 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 548         (elm)->field.cqe_next = (head)->cqh_first;                      \
 549         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 550         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 551                 (head)->cqh_last = (elm);                               \
 552         else                                                            \
 553                 (head)->cqh_first->field.cqe_prev = (elm);              \
 554         (head)->cqh_first = (elm);                                      \
 555 } while (0)
 556
 557 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 558         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 559         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 560         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 561                 (head)->cqh_first = (elm);                              \
 562         else                                                            \
 563                 (head)->cqh_last->field.cqe_next = (elm);               \
 564         (head)->cqh_last = (elm);                                       \
 565 } while (0)
 566
 567 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 568         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 569                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 570         else                                                            \
 571                 (elm)->field.cqe_next->field.cqe_prev =                 \
 572                     (elm)->field.cqe_prev;                              \
 573         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 574                 (head)->cqh_first = (elm)->field.cqe_next;              \
 575         else                                                            \
 576                 (elm)->field.cqe_prev->field.cqe_next =                 \
 577                     (elm)->field.cqe_next;                              \
 578 } while (0)
 579
 580 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 581         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 582             CIRCLEQ_END(head))                                          \
 583                 (head).cqh_last = (elm2);                               \
 584         else                                                            \
 585                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 586         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 587             CIRCLEQ_END(head))                                          \
 588                 (head).cqh_first = (elm2);                              \
 589         else                                                            \
 590                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 591 } while (0)
 592
 593 #endif  /* !_FAKE_QUEUE_H_ */