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_FOREACH_SAFE
  49 #undef SLIST_FIRST
  50 #undef SLIST_END
  51 #undef SLIST_EMPTY
  52 #undef SLIST_NEXT
  53 #undef SLIST_FOREACH
  54 #undef SLIST_INIT
  55 #undef SLIST_INSERT_AFTER
  56 #undef SLIST_INSERT_HEAD
  57 #undef SLIST_REMOVE_HEAD
  58 #undef SLIST_REMOVE_AFTER
  59 #undef SLIST_REMOVE
  60 #undef SLIST_REMOVE_NEXT
  61 #undef LIST_HEAD
  62 #undef LIST_HEAD_INITIALIZER
  63 #undef LIST_ENTRY
  64 #undef LIST_FIRST
  65 #undef LIST_END
  66 #undef LIST_EMPTY
  67 #undef LIST_NEXT
  68 #undef LIST_FOREACH
  69 #undef LIST_FOREACH_SAFE
  70 #undef LIST_INIT
  71 #undef LIST_INSERT_AFTER
  72 #undef LIST_INSERT_BEFORE
  73 #undef LIST_INSERT_HEAD
  74 #undef LIST_REMOVE
  75 #undef LIST_REPLACE
  76 #undef SIMPLEQ_HEAD
  77 #undef SIMPLEQ_HEAD_INITIALIZER
  78 #undef SIMPLEQ_ENTRY
  79 #undef SIMPLEQ_FIRST
  80 #undef SIMPLEQ_END
  81 #undef SIMPLEQ_EMPTY
  82 #undef SIMPLEQ_NEXT
  83 #undef SIMPLEQ_FOREACH
  84 #undef SIMPLEQ_INIT
  85 #undef SIMPLEQ_INSERT_HEAD
  86 #undef SIMPLEQ_INSERT_TAIL
  87 #undef SIMPLEQ_INSERT_AFTER
  88 #undef SIMPLEQ_REMOVE_HEAD
  89 #undef TAILQ_HEAD
  90 #undef TAILQ_HEAD_INITIALIZER
  91 #undef TAILQ_ENTRY
  92 #undef TAILQ_FIRST
  93 #undef TAILQ_END
  94 #undef TAILQ_NEXT
  95 #undef TAILQ_LAST
  96 #undef TAILQ_PREV
  97 #undef TAILQ_EMPTY
  98 #undef TAILQ_FOREACH
  99 #undef TAILQ_FOREACH_REVERSE
 100 #undef TAILQ_FOREACH_SAFE
 101 #undef TAILQ_FOREACH_REVERSE_SAFE
 102 #undef TAILQ_INIT
 103 #undef TAILQ_INSERT_HEAD
 104 #undef TAILQ_INSERT_TAIL
 105 #undef TAILQ_INSERT_AFTER
 106 #undef TAILQ_INSERT_BEFORE
 107 #undef TAILQ_REMOVE
 108 #undef TAILQ_REPLACE
 109 #undef CIRCLEQ_HEAD
 110 #undef CIRCLEQ_HEAD_INITIALIZER
 111 #undef CIRCLEQ_ENTRY
 112 #undef CIRCLEQ_FIRST
 113 #undef CIRCLEQ_LAST
 114 #undef CIRCLEQ_END
 115 #undef CIRCLEQ_NEXT
 116 #undef CIRCLEQ_PREV
 117 #undef CIRCLEQ_EMPTY
 118 #undef CIRCLEQ_FOREACH
 119 #undef CIRCLEQ_FOREACH_REVERSE
 120 #undef CIRCLEQ_INIT
 121 #undef CIRCLEQ_INSERT_AFTER
 122 #undef CIRCLEQ_INSERT_BEFORE
 123 #undef CIRCLEQ_INSERT_HEAD
 124 #undef CIRCLEQ_INSERT_TAIL
 125 #undef CIRCLEQ_REMOVE
 126 #undef CIRCLEQ_REPLACE
 127
 128 /*
 129  * This file defines five types of data structures: singly-linked lists,
 130  * lists, simple queues, tail queues, and circular queues.
 131  *
 132  *
 133  * A singly-linked list is headed by a single forward pointer. The elements
 134  * are singly linked for minimum space and pointer manipulation overhead at
 135  * the expense of O(n) removal for arbitrary elements. New elements can be
 136  * added to the list after an existing element or at the head of the list.
 137  * Elements being removed from the head of the list should use the explicit
 138  * macro for this purpose for optimum efficiency. A singly-linked list may
 139  * only be traversed in the forward direction.  Singly-linked lists are ideal
 140  * for applications with large datasets and few or no removals or for
 141  * implementing a LIFO queue.
 142  *
 143  * A list is headed by a single forward pointer (or an array of forward
 144  * pointers for a hash table header). The elements are doubly linked
 145  * so that an arbitrary element can be removed without a need to
 146  * traverse the list. New elements can be added to the list before
 147  * or after an existing element or at the head of the list. A list
 148  * may only be traversed in the forward direction.
 149  *
 150  * A simple queue is headed by a pair of pointers, one the head of the
 151  * list and the other to the tail of the list. The elements are singly
 152  * linked to save space, so elements can only be removed from the
 153  * head of the list. New elements can be added to the list before or after
 154  * an existing element, at the head of the list, or at the end of the
 155  * list. A simple queue may only be traversed in the forward direction.
 156  *
 157  * A tail queue is headed by a pair of pointers, one to the head of the
 158  * list and the other to the tail of the list. The elements are doubly
 159  * linked so that an arbitrary element can be removed without a need to
 160  * traverse the list. New elements can be added to the list before or
 161  * after an existing element, at the head of the list, or at the end of
 162  * the list. A tail queue may be traversed in either direction.
 163  *
 164  * A circle queue is headed by a pair of pointers, one to the head of the
 165  * list and the other to the tail of the list. The elements are doubly
 166  * linked so that an arbitrary element can be removed without a need to
 167  * traverse the list. New elements can be added to the list before or after
 168  * an existing element, at the head of the list, or at the end of the list.
 169  * A circle queue may be traversed in either direction, but has a more
 170  * complex end of list detection.
 171  *
 172  * For details on the use of these macros, see the queue(3) manual page.
 173  */
 174
 175 #if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
 176 #define _Q_INVALIDATE(a) (a) = ((void *)-1)
 177 #else
 178 #define _Q_INVALIDATE(a)
 179 #endif
 180
 181 /*
 182  * Singly-linked List definitions.
 183  */
 184 #define SLIST_HEAD(name, type)                                          \
 185 struct name {                                                           \
 186         struct type *slh_first; /* first element */                     \
 187 }
 188
 189 #define SLIST_HEAD_INITIALIZER(head)                                    \
 190         { NULL }
 191
 192 #define SLIST_ENTRY(type)                                               \
 193 struct {                                                                \
 194         struct type *sle_next;  /* next element */                      \
 195 }
 196
 197 /*
 198  * Singly-linked List access methods.
 199  */
 200 #define SLIST_FIRST(head)       ((head)->slh_first)
 201 #define SLIST_END(head)         NULL
 202 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 203 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 204
 205 #define SLIST_FOREACH(var, head, field)                                 \
 206         for((var) = SLIST_FIRST(head);                                  \
 207             (var) != SLIST_END(head);                                   \
 208             (var) = SLIST_NEXT(var, field))
 209
 210 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 211         for ((var) = SLIST_FIRST(head);                         \
 212             (var) && ((tvar) = SLIST_NEXT(var, field), 1);              \
 213             (var) = (tvar))
 214
 215 /*
 216  * Singly-linked List functions.
 217  */
 218 #define SLIST_INIT(head) {                                              \
 219         SLIST_FIRST(head) = SLIST_END(head);                            \
 220 }
 221
 222 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 223         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 224         (slistelm)->field.sle_next = (elm);                             \
 225 } while (0)
 226
 227 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 228         (elm)->field.sle_next = (head)->slh_first;                      \
 229         (head)->slh_first = (elm);                                      \
 230 } while (0)
 231
 232 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 233         (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;  \
 234 } while (0)
 235
 236 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 237         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 238 } while (0)
 239
 240 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 241         if ((head)->slh_first == (elm)) {                               \
 242                 SLIST_REMOVE_HEAD((head), field);                       \
 243         } else {                                                        \
 244                 struct type *curelm = (head)->slh_first;                \
 245                                                                         \
 246                 while (curelm->field.sle_next != (elm))                 \
 247                         curelm = curelm->field.sle_next;                \
 248                 curelm->field.sle_next =                                \
 249                     curelm->field.sle_next->field.sle_next;             \
 250                 _Q_INVALIDATE((elm)->field.sle_next);                   \
 251         }                                                               \
 252 } while (0)
 253
 254 /*
 255  * List definitions.
 256  */
 257 #define LIST_HEAD(name, type)                                           \
 258 struct name {                                                           \
 259         struct type *lh_first;  /* first element */                     \
 260 }
 261
 262 #define LIST_HEAD_INITIALIZER(head)                                     \
 263         { NULL }
 264
 265 #define LIST_ENTRY(type)                                                \
 266 struct {                                                                \
 267         struct type *le_next;   /* next element */                      \
 268         struct type **le_prev;  /* address of previous next element */  \
 269 }
 270
 271 /*
 272  * List access methods
 273  */
 274 #define LIST_FIRST(head)                ((head)->lh_first)
 275 #define LIST_END(head)                  NULL
 276 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 277 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 278
 279 #define LIST_FOREACH(var, head, field)                                  \
 280         for((var) = LIST_FIRST(head);                                   \
 281             (var)!= LIST_END(head);                                     \
 282             (var) = LIST_NEXT(var, field))
 283
 284 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 285         for ((var) = LIST_FIRST(head);                          \
 286             (var) && ((tvar) = LIST_NEXT(var, field), 1);               \
 287             (var) = (tvar))
 288
 289 /*
 290  * List functions.
 291  */
 292 #define LIST_INIT(head) do {                                            \
 293         LIST_FIRST(head) = LIST_END(head);                              \
 294 } while (0)
 295
 296 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 297         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 298                 (listelm)->field.le_next->field.le_prev =               \
 299                     &(elm)->field.le_next;                              \
 300         (listelm)->field.le_next = (elm);                               \
 301         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 302 } while (0)
 303
 304 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 305         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 306         (elm)->field.le_next = (listelm);                               \
 307         *(listelm)->field.le_prev = (elm);                              \
 308         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 309 } while (0)
 310
 311 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 312         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 313                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 314         (head)->lh_first = (elm);                                       \
 315         (elm)->field.le_prev = &(head)->lh_first;                       \
 316 } while (0)
 317
 318 #define LIST_REMOVE(elm, field) do {                                    \
 319         if ((elm)->field.le_next != NULL)                               \
 320                 (elm)->field.le_next->field.le_prev =                   \
 321                     (elm)->field.le_prev;                               \
 322         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 323         _Q_INVALIDATE((elm)->field.le_prev);                            \
 324         _Q_INVALIDATE((elm)->field.le_next);                            \
 325 } while (0)
 326
 327 #define LIST_REPLACE(elm, elm2, field) do {                             \
 328         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 329                 (elm2)->field.le_next->field.le_prev =                  \
 330                     &(elm2)->field.le_next;                             \
 331         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 332         *(elm2)->field.le_prev = (elm2);                                \
 333         _Q_INVALIDATE((elm)->field.le_prev);                            \
 334         _Q_INVALIDATE((elm)->field.le_next);                            \
 335 } while (0)
 336
 337 /*
 338  * Simple queue definitions.
 339  */
 340 #define SIMPLEQ_HEAD(name, type)                                        \
 341 struct name {                                                           \
 342         struct type *sqh_first; /* first element */                     \
 343         struct type **sqh_last; /* addr of last next element */         \
 344 }
 345
 346 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 347         { NULL, &(head).sqh_first }
 348
 349 #define SIMPLEQ_ENTRY(type)                                             \
 350 struct {                                                                \
 351         struct type *sqe_next;  /* next element */                      \
 352 }
 353
 354 /*
 355  * Simple queue access methods.
 356  */
 357 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 358 #define SIMPLEQ_END(head)           NULL
 359 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 360 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 361
 362 #define SIMPLEQ_FOREACH(var, head, field)                               \
 363         for((var) = SIMPLEQ_FIRST(head);                                \
 364             (var) != SIMPLEQ_END(head);                                 \
 365             (var) = SIMPLEQ_NEXT(var, field))
 366
 367 #define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 368         for ((var) = SIMPLEQ_FIRST(head);                               \
 369             (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1);            \
 370             (var) = (tvar))
 371
 372 /*
 373  * Simple queue functions.
 374  */
 375 #define SIMPLEQ_INIT(head) do {                                         \
 376         (head)->sqh_first = NULL;                                       \
 377         (head)->sqh_last = &(head)->sqh_first;                          \
 378 } while (0)
 379
 380 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 381         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 382                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 383         (head)->sqh_first = (elm);                                      \
 384 } while (0)
 385
 386 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 387         (elm)->field.sqe_next = NULL;                                   \
 388         *(head)->sqh_last = (elm);                                      \
 389         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 390 } while (0)
 391
 392 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 393         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 394                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 395         (listelm)->field.sqe_next = (elm);                              \
 396 } while (0)
 397
 398 #define SIMPLEQ_REMOVE_HEAD(head, field) do {                   \
 399         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 400                 (head)->sqh_last = &(head)->sqh_first;                  \
 401 } while (0)
 402
 403 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {                     \
 404         if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
 405             == NULL)                                                    \
 406                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 407 } while (0)
 408
 409 /*
 410  * Tail queue definitions.
 411  */
 412 #define TAILQ_HEAD(name, type)                                          \
 413 struct name {                                                           \
 414         struct type *tqh_first; /* first element */                     \
 415         struct type **tqh_last; /* addr of last next element */         \
 416 }
 417
 418 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 419         { NULL, &(head).tqh_first }
 420
 421 #define TAILQ_ENTRY(type)                                               \
 422 struct {                                                                \
 423         struct type *tqe_next;  /* next element */                      \
 424         struct type **tqe_prev; /* address of previous next element */  \
 425 }
 426
 427 /*
 428  * tail queue access methods
 429  */
 430 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 431 #define TAILQ_END(head)                 NULL
 432 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 433 #define TAILQ_LAST(head, headname)                                      \
 434         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 435 /* XXX */
 436 #define TAILQ_PREV(elm, headname, field)                                \
 437         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 438 #define TAILQ_EMPTY(head)                                               \
 439         (TAILQ_FIRST(head) == TAILQ_END(head))
 440
 441 #define TAILQ_FOREACH(var, head, field)                                 \
 442         for((var) = TAILQ_FIRST(head);                                  \
 443             (var) != TAILQ_END(head);                                   \
 444             (var) = TAILQ_NEXT(var, field))
 445
 446 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 447         for ((var) = TAILQ_FIRST(head);                                 \
 448             (var) != TAILQ_END(head) &&                                 \
 449             ((tvar) = TAILQ_NEXT(var, field), 1);                       \
 450             (var) = (tvar))
 451
 452
 453 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 454         for((var) = TAILQ_LAST(head, headname);                         \
 455             (var) != TAILQ_END(head);                                   \
 456             (var) = TAILQ_PREV(var, headname, field))
 457
 458 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 459         for ((var) = TAILQ_LAST(head, headname);                        \
 460             (var) != TAILQ_END(head) &&                                 \
 461             ((tvar) = TAILQ_PREV(var, headname, field), 1);             \
 462             (var) = (tvar))
 463
 464 /*
 465  * Tail queue functions.
 466  */
 467 #define TAILQ_INIT(head) do {                                           \
 468         (head)->tqh_first = NULL;                                       \
 469         (head)->tqh_last = &(head)->tqh_first;                          \
 470 } while (0)
 471
 472 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 473         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 474                 (head)->tqh_first->field.tqe_prev =                     \
 475                     &(elm)->field.tqe_next;                             \
 476         else                                                            \
 477                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 478         (head)->tqh_first = (elm);                                      \
 479         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 480 } while (0)
 481
 482 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 483         (elm)->field.tqe_next = NULL;                                   \
 484         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 485         *(head)->tqh_last = (elm);                                      \
 486         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 487 } while (0)
 488
 489 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 490         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 491                 (elm)->field.tqe_next->field.tqe_prev =                 \
 492                     &(elm)->field.tqe_next;                             \
 493         else                                                            \
 494                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 495         (listelm)->field.tqe_next = (elm);                              \
 496         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 497 } while (0)
 498
 499 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 500         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 501         (elm)->field.tqe_next = (listelm);                              \
 502         *(listelm)->field.tqe_prev = (elm);                             \
 503         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 504 } while (0)
 505
 506 #define TAILQ_REMOVE(head, elm, field) do {                             \
 507         if (((elm)->field.tqe_next) != NULL)                            \
 508                 (elm)->field.tqe_next->field.tqe_prev =                 \
 509                     (elm)->field.tqe_prev;                              \
 510         else                                                            \
 511                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 512         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 513         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 514         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 515 } while (0)
 516
 517 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 518         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 519                 (elm2)->field.tqe_next->field.tqe_prev =                \
 520                     &(elm2)->field.tqe_next;                            \
 521         else                                                            \
 522                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 523         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 524         *(elm2)->field.tqe_prev = (elm2);                               \
 525         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 526         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 527 } while (0)
 528
 529 /*
 530  * Circular queue definitions.
 531  */
 532 #define CIRCLEQ_HEAD(name, type)                                        \
 533 struct name {                                                           \
 534         struct type *cqh_first;         /* first element */             \
 535         struct type *cqh_last;          /* last element */              \
 536 }
 537
 538 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 539         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 540
 541 #define CIRCLEQ_ENTRY(type)                                             \
 542 struct {                                                                \
 543         struct type *cqe_next;          /* next element */              \
 544         struct type *cqe_prev;          /* previous element */          \
 545 }
 546
 547 /*
 548  * Circular queue access methods
 549  */
 550 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 551 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 552 #define CIRCLEQ_END(head)               ((void *)(head))
 553 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 554 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 555 #define CIRCLEQ_EMPTY(head)                                             \
 556         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 557
 558 #define CIRCLEQ_FOREACH(var, head, field)                               \
 559         for((var) = CIRCLEQ_FIRST(head);                                \
 560             (var) != CIRCLEQ_END(head);                                 \
 561             (var) = CIRCLEQ_NEXT(var, field))
 562
 563 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 564         for ((var) = CIRCLEQ_FIRST(head);                               \
 565             (var) != CIRCLEQ_END(head) &&                               \
 566             ((tvar) = CIRCLEQ_NEXT(var, field), 1);                     \
 567             (var) = (tvar))
 568
 569 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 570         for((var) = CIRCLEQ_LAST(head);                                 \
 571             (var) != CIRCLEQ_END(head);                                 \
 572             (var) = CIRCLEQ_PREV(var, field))
 573
 574 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)  \
 575         for ((var) = CIRCLEQ_LAST(head, headname);                      \
 576             (var) != CIRCLEQ_END(head) &&                               \
 577             ((tvar) = CIRCLEQ_PREV(var, headname, field), 1);           \
 578             (var) = (tvar))
 579
 580 /*
 581  * Circular queue functions.
 582  */
 583 #define CIRCLEQ_INIT(head) do {                                         \
 584         (head)->cqh_first = CIRCLEQ_END(head);                          \
 585         (head)->cqh_last = CIRCLEQ_END(head);                           \
 586 } while (0)
 587
 588 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 589         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 590         (elm)->field.cqe_prev = (listelm);                              \
 591         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 592                 (head)->cqh_last = (elm);                               \
 593         else                                                            \
 594                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 595         (listelm)->field.cqe_next = (elm);                              \
 596 } while (0)
 597
 598 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 599         (elm)->field.cqe_next = (listelm);                              \
 600         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 601         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 602                 (head)->cqh_first = (elm);                              \
 603         else                                                            \
 604                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 605         (listelm)->field.cqe_prev = (elm);                              \
 606 } while (0)
 607
 608 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 609         (elm)->field.cqe_next = (head)->cqh_first;                      \
 610         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 611         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 612                 (head)->cqh_last = (elm);                               \
 613         else                                                            \
 614                 (head)->cqh_first->field.cqe_prev = (elm);              \
 615         (head)->cqh_first = (elm);                                      \
 616 } while (0)
 617
 618 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 619         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 620         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 621         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 622                 (head)->cqh_first = (elm);                              \
 623         else                                                            \
 624                 (head)->cqh_last->field.cqe_next = (elm);               \
 625         (head)->cqh_last = (elm);                                       \
 626 } while (0)
 627
 628 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 629         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 630                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 631         else                                                            \
 632                 (elm)->field.cqe_next->field.cqe_prev =                 \
 633                     (elm)->field.cqe_prev;                              \
 634         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 635                 (head)->cqh_first = (elm)->field.cqe_next;              \
 636         else                                                            \
 637                 (elm)->field.cqe_prev->field.cqe_next =                 \
 638                     (elm)->field.cqe_next;                              \
 639         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 640         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 641 } while (0)
 642
 643 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 644         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 645             CIRCLEQ_END(head))                                          \
 646                 (head).cqh_last = (elm2);                               \
 647         else                                                            \
 648                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 649         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 650             CIRCLEQ_END(head))                                          \
 651                 (head).cqh_first = (elm2);                              \
 652         else                                                            \
 653                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 654         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 655         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 656 } while (0)
 657
 658 #endif  /* !_FAKE_QUEUE_H_ */