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

   1 /*      $OpenBSD: queue.h,v 1.36 2012/04/11 13:29:14 naddy 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. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  33  */
  34
  35 /* OPENBSD ORIGINAL: sys/sys/queue.h */
  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 #if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
 171 #define _Q_INVALIDATE(a) (a) = ((void *)-1)
 172 #else
 173 #define _Q_INVALIDATE(a)
 174 #endif
 175
 176 /*
 177  * Singly-linked List definitions.
 178  */
 179 #define SLIST_HEAD(name, type)                                          \
 180 struct name {                                                           \
 181         struct type *slh_first; /* first element */                     \
 182 }
 183
 184 #define SLIST_HEAD_INITIALIZER(head)                                    \
 185         { NULL }
 186
 187 #define SLIST_ENTRY(type)                                               \
 188 struct {                                                                \
 189         struct type *sle_next;  /* next element */                      \
 190 }
 191
 192 /*
 193  * Singly-linked List access methods.
 194  */
 195 #define SLIST_FIRST(head)       ((head)->slh_first)
 196 #define SLIST_END(head)         NULL
 197 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 198 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 199
 200 #define SLIST_FOREACH(var, head, field)                                 \
 201         for((var) = SLIST_FIRST(head);                                  \
 202             (var) != SLIST_END(head);                                   \
 203             (var) = SLIST_NEXT(var, field))
 204
 205 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 206         for ((var) = SLIST_FIRST(head);                         \
 207             (var) && ((tvar) = SLIST_NEXT(var, field), 1);              \
 208             (var) = (tvar))
 209
 210 /*
 211  * Singly-linked List functions.
 212  */
 213 #define SLIST_INIT(head) {                                              \
 214         SLIST_FIRST(head) = SLIST_END(head);                            \
 215 }
 216
 217 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 218         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 219         (slistelm)->field.sle_next = (elm);                             \
 220 } while (0)
 221
 222 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 223         (elm)->field.sle_next = (head)->slh_first;                      \
 224         (head)->slh_first = (elm);                                      \
 225 } while (0)
 226
 227 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 228         (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;  \
 229 } while (0)
 230
 231 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 232         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 233 } while (0)
 234
 235 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 236         if ((head)->slh_first == (elm)) {                               \
 237                 SLIST_REMOVE_HEAD((head), field);                       \
 238         } else {                                                        \
 239                 struct type *curelm = (head)->slh_first;                \
 240                                                                         \
 241                 while (curelm->field.sle_next != (elm))                 \
 242                         curelm = curelm->field.sle_next;                \
 243                 curelm->field.sle_next =                                \
 244                     curelm->field.sle_next->field.sle_next;             \
 245                 _Q_INVALIDATE((elm)->field.sle_next);                   \
 246         }                                                               \
 247 } while (0)
 248
 249 /*
 250  * List definitions.
 251  */
 252 #define LIST_HEAD(name, type)                                           \
 253 struct name {                                                           \
 254         struct type *lh_first;  /* first element */                     \
 255 }
 256
 257 #define LIST_HEAD_INITIALIZER(head)                                     \
 258         { NULL }
 259
 260 #define LIST_ENTRY(type)                                                \
 261 struct {                                                                \
 262         struct type *le_next;   /* next element */                      \
 263         struct type **le_prev;  /* address of previous next element */  \
 264 }
 265
 266 /*
 267  * List access methods
 268  */
 269 #define LIST_FIRST(head)                ((head)->lh_first)
 270 #define LIST_END(head)                  NULL
 271 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 272 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 273
 274 #define LIST_FOREACH(var, head, field)                                  \
 275         for((var) = LIST_FIRST(head);                                   \
 276             (var)!= LIST_END(head);                                     \
 277             (var) = LIST_NEXT(var, field))
 278
 279 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 280         for ((var) = LIST_FIRST(head);                          \
 281             (var) && ((tvar) = LIST_NEXT(var, field), 1);               \
 282             (var) = (tvar))
 283
 284 /*
 285  * List functions.
 286  */
 287 #define LIST_INIT(head) do {                                            \
 288         LIST_FIRST(head) = LIST_END(head);                              \
 289 } while (0)
 290
 291 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 292         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 293                 (listelm)->field.le_next->field.le_prev =               \
 294                     &(elm)->field.le_next;                              \
 295         (listelm)->field.le_next = (elm);                               \
 296         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 297 } while (0)
 298
 299 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 300         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 301         (elm)->field.le_next = (listelm);                               \
 302         *(listelm)->field.le_prev = (elm);                              \
 303         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 304 } while (0)
 305
 306 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 307         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 308                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 309         (head)->lh_first = (elm);                                       \
 310         (elm)->field.le_prev = &(head)->lh_first;                       \
 311 } while (0)
 312
 313 #define LIST_REMOVE(elm, field) do {                                    \
 314         if ((elm)->field.le_next != NULL)                               \
 315                 (elm)->field.le_next->field.le_prev =                   \
 316                     (elm)->field.le_prev;                               \
 317         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 318         _Q_INVALIDATE((elm)->field.le_prev);                            \
 319         _Q_INVALIDATE((elm)->field.le_next);                            \
 320 } while (0)
 321
 322 #define LIST_REPLACE(elm, elm2, field) do {                             \
 323         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 324                 (elm2)->field.le_next->field.le_prev =                  \
 325                     &(elm2)->field.le_next;                             \
 326         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 327         *(elm2)->field.le_prev = (elm2);                                \
 328         _Q_INVALIDATE((elm)->field.le_prev);                            \
 329         _Q_INVALIDATE((elm)->field.le_next);                            \
 330 } while (0)
 331
 332 /*
 333  * Simple queue definitions.
 334  */
 335 #define SIMPLEQ_HEAD(name, type)                                        \
 336 struct name {                                                           \
 337         struct type *sqh_first; /* first element */                     \
 338         struct type **sqh_last; /* addr of last next element */         \
 339 }
 340
 341 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 342         { NULL, &(head).sqh_first }
 343
 344 #define SIMPLEQ_ENTRY(type)                                             \
 345 struct {                                                                \
 346         struct type *sqe_next;  /* next element */                      \
 347 }
 348
 349 /*
 350  * Simple queue access methods.
 351  */
 352 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 353 #define SIMPLEQ_END(head)           NULL
 354 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 355 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 356
 357 #define SIMPLEQ_FOREACH(var, head, field)                               \
 358         for((var) = SIMPLEQ_FIRST(head);                                \
 359             (var) != SIMPLEQ_END(head);                                 \
 360             (var) = SIMPLEQ_NEXT(var, field))
 361
 362 #define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 363         for ((var) = SIMPLEQ_FIRST(head);                               \
 364             (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1);            \
 365             (var) = (tvar))
 366
 367 /*
 368  * Simple queue functions.
 369  */
 370 #define SIMPLEQ_INIT(head) do {                                         \
 371         (head)->sqh_first = NULL;                                       \
 372         (head)->sqh_last = &(head)->sqh_first;                          \
 373 } while (0)
 374
 375 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 376         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 377                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 378         (head)->sqh_first = (elm);                                      \
 379 } while (0)
 380
 381 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 382         (elm)->field.sqe_next = NULL;                                   \
 383         *(head)->sqh_last = (elm);                                      \
 384         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 385 } while (0)
 386
 387 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 388         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 389                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 390         (listelm)->field.sqe_next = (elm);                              \
 391 } while (0)
 392
 393 #define SIMPLEQ_REMOVE_HEAD(head, field) do {                   \
 394         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 395                 (head)->sqh_last = &(head)->sqh_first;                  \
 396 } while (0)
 397
 398 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {                     \
 399         if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
 400             == NULL)                                                    \
 401                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 402 } while (0)
 403
 404 /*
 405  * Tail queue definitions.
 406  */
 407 #define TAILQ_HEAD(name, type)                                          \
 408 struct name {                                                           \
 409         struct type *tqh_first; /* first element */                     \
 410         struct type **tqh_last; /* addr of last next element */         \
 411 }
 412
 413 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 414         { NULL, &(head).tqh_first }
 415
 416 #define TAILQ_ENTRY(type)                                               \
 417 struct {                                                                \
 418         struct type *tqe_next;  /* next element */                      \
 419         struct type **tqe_prev; /* address of previous next element */  \
 420 }
 421
 422 /*
 423  * tail queue access methods
 424  */
 425 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 426 #define TAILQ_END(head)                 NULL
 427 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 428 #define TAILQ_LAST(head, headname)                                      \
 429         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 430 /* XXX */
 431 #define TAILQ_PREV(elm, headname, field)                                \
 432         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 433 #define TAILQ_EMPTY(head)                                               \
 434         (TAILQ_FIRST(head) == TAILQ_END(head))
 435
 436 #define TAILQ_FOREACH(var, head, field)                                 \
 437         for((var) = TAILQ_FIRST(head);                                  \
 438             (var) != TAILQ_END(head);                                   \
 439             (var) = TAILQ_NEXT(var, field))
 440
 441 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 442         for ((var) = TAILQ_FIRST(head);                                 \
 443             (var) != TAILQ_END(head) &&                                 \
 444             ((tvar) = TAILQ_NEXT(var, field), 1);                       \
 445             (var) = (tvar))
 446
 447
 448 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 449         for((var) = TAILQ_LAST(head, headname);                         \
 450             (var) != TAILQ_END(head);                                   \
 451             (var) = TAILQ_PREV(var, headname, field))
 452
 453 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 454         for ((var) = TAILQ_LAST(head, headname);                        \
 455             (var) != TAILQ_END(head) &&                                 \
 456             ((tvar) = TAILQ_PREV(var, headname, field), 1);             \
 457             (var) = (tvar))
 458
 459 /*
 460  * Tail queue functions.
 461  */
 462 #define TAILQ_INIT(head) do {                                           \
 463         (head)->tqh_first = NULL;                                       \
 464         (head)->tqh_last = &(head)->tqh_first;                          \
 465 } while (0)
 466
 467 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 468         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 469                 (head)->tqh_first->field.tqe_prev =                     \
 470                     &(elm)->field.tqe_next;                             \
 471         else                                                            \
 472                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 473         (head)->tqh_first = (elm);                                      \
 474         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 475 } while (0)
 476
 477 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 478         (elm)->field.tqe_next = NULL;                                   \
 479         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 480         *(head)->tqh_last = (elm);                                      \
 481         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 482 } while (0)
 483
 484 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 485         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 486                 (elm)->field.tqe_next->field.tqe_prev =                 \
 487                     &(elm)->field.tqe_next;                             \
 488         else                                                            \
 489                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 490         (listelm)->field.tqe_next = (elm);                              \
 491         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 492 } while (0)
 493
 494 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 495         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 496         (elm)->field.tqe_next = (listelm);                              \
 497         *(listelm)->field.tqe_prev = (elm);                             \
 498         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 499 } while (0)
 500
 501 #define TAILQ_REMOVE(head, elm, field) do {                             \
 502         if (((elm)->field.tqe_next) != NULL)                            \
 503                 (elm)->field.tqe_next->field.tqe_prev =                 \
 504                     (elm)->field.tqe_prev;                              \
 505         else                                                            \
 506                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 507         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 508         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 509         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 510 } while (0)
 511
 512 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 513         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 514                 (elm2)->field.tqe_next->field.tqe_prev =                \
 515                     &(elm2)->field.tqe_next;                            \
 516         else                                                            \
 517                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 518         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 519         *(elm2)->field.tqe_prev = (elm2);                               \
 520         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 521         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 522 } while (0)
 523
 524 /*
 525  * Circular queue definitions.
 526  */
 527 #define CIRCLEQ_HEAD(name, type)                                        \
 528 struct name {                                                           \
 529         struct type *cqh_first;         /* first element */             \
 530         struct type *cqh_last;          /* last element */              \
 531 }
 532
 533 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 534         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 535
 536 #define CIRCLEQ_ENTRY(type)                                             \
 537 struct {                                                                \
 538         struct type *cqe_next;          /* next element */              \
 539         struct type *cqe_prev;          /* previous element */          \
 540 }
 541
 542 /*
 543  * Circular queue access methods
 544  */
 545 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 546 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 547 #define CIRCLEQ_END(head)               ((void *)(head))
 548 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 549 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 550 #define CIRCLEQ_EMPTY(head)                                             \
 551         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 552
 553 #define CIRCLEQ_FOREACH(var, head, field)                               \
 554         for((var) = CIRCLEQ_FIRST(head);                                \
 555             (var) != CIRCLEQ_END(head);                                 \
 556             (var) = CIRCLEQ_NEXT(var, field))
 557
 558 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 559         for ((var) = CIRCLEQ_FIRST(head);                               \
 560             (var) != CIRCLEQ_END(head) &&                               \
 561             ((tvar) = CIRCLEQ_NEXT(var, field), 1);                     \
 562             (var) = (tvar))
 563
 564 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 565         for((var) = CIRCLEQ_LAST(head);                                 \
 566             (var) != CIRCLEQ_END(head);                                 \
 567             (var) = CIRCLEQ_PREV(var, field))
 568
 569 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)  \
 570         for ((var) = CIRCLEQ_LAST(head, headname);                      \
 571             (var) != CIRCLEQ_END(head) &&                               \
 572             ((tvar) = CIRCLEQ_PREV(var, headname, field), 1);           \
 573             (var) = (tvar))
 574
 575 /*
 576  * Circular queue functions.
 577  */
 578 #define CIRCLEQ_INIT(head) do {                                         \
 579         (head)->cqh_first = CIRCLEQ_END(head);                          \
 580         (head)->cqh_last = CIRCLEQ_END(head);                           \
 581 } while (0)
 582
 583 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 584         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 585         (elm)->field.cqe_prev = (listelm);                              \
 586         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 587                 (head)->cqh_last = (elm);                               \
 588         else                                                            \
 589                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 590         (listelm)->field.cqe_next = (elm);                              \
 591 } while (0)
 592
 593 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 594         (elm)->field.cqe_next = (listelm);                              \
 595         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 596         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 597                 (head)->cqh_first = (elm);                              \
 598         else                                                            \
 599                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 600         (listelm)->field.cqe_prev = (elm);                              \
 601 } while (0)
 602
 603 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 604         (elm)->field.cqe_next = (head)->cqh_first;                      \
 605         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 606         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 607                 (head)->cqh_last = (elm);                               \
 608         else                                                            \
 609                 (head)->cqh_first->field.cqe_prev = (elm);              \
 610         (head)->cqh_first = (elm);                                      \
 611 } while (0)
 612
 613 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 614         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 615         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 616         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 617                 (head)->cqh_first = (elm);                              \
 618         else                                                            \
 619                 (head)->cqh_last->field.cqe_next = (elm);               \
 620         (head)->cqh_last = (elm);                                       \
 621 } while (0)
 622
 623 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 624         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 625                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 626         else                                                            \
 627                 (elm)->field.cqe_next->field.cqe_prev =                 \
 628                     (elm)->field.cqe_prev;                              \
 629         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 630                 (head)->cqh_first = (elm)->field.cqe_next;              \
 631         else                                                            \
 632                 (elm)->field.cqe_prev->field.cqe_next =                 \
 633                     (elm)->field.cqe_next;                              \
 634         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 635         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 636 } while (0)
 637
 638 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 639         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 640             CIRCLEQ_END(head))                                          \
 641                 (head).cqh_last = (elm2);                               \
 642         else                                                            \
 643                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 644         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 645             CIRCLEQ_END(head))                                          \
 646                 (head).cqh_first = (elm2);                              \
 647         else                                                            \
 648                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 649         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 650         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 651 } while (0)
 652
 653 #endif  /* !_FAKE_QUEUE_H_ */