code.delx.au - spectrwm/blob - osx/queue.h

   1 /*      $OpenBSD: queue.h,v 1.38 2013/07/03 15:05:21 fgsch 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 #ifndef _SYS_QUEUE_H_
  36 #define _SYS_QUEUE_H_
  37
  38 /*
  39  * This file defines five types of data structures: singly-linked lists,
  40  * lists, simple queues, tail queues, and circular queues.
  41  *
  42  *
  43  * A singly-linked list is headed by a single forward pointer. The elements
  44  * are singly linked for minimum space and pointer manipulation overhead at
  45  * the expense of O(n) removal for arbitrary elements. New elements can be
  46  * added to the list after an existing element or at the head of the list.
  47  * Elements being removed from the head of the list should use the explicit
  48  * macro for this purpose for optimum efficiency. A singly-linked list may
  49  * only be traversed in the forward direction.  Singly-linked lists are ideal
  50  * for applications with large datasets and few or no removals or for
  51  * implementing a LIFO queue.
  52  *
  53  * A list is headed by a single forward pointer (or an array of forward
  54  * pointers for a hash table header). The elements are doubly linked
  55  * so that an arbitrary element can be removed without a need to
  56  * traverse the list. New elements can be added to the list before
  57  * or after an existing element or at the head of the list. A list
  58  * may only be traversed in the forward direction.
  59  *
  60  * A simple queue is headed by a pair of pointers, one the head of the
  61  * list and the other to the tail of the list. The elements are singly
  62  * linked to save space, so elements can only be removed from the
  63  * head of the list. New elements can be added to the list before or after
  64  * an existing element, at the head of the list, or at the end of the
  65  * list. A simple queue may only be traversed in the forward direction.
  66  *
  67  * A tail queue is headed by a pair of pointers, one to the head of the
  68  * list and the other to the tail of the list. The elements are doubly
  69  * linked so that an arbitrary element can be removed without a need to
  70  * traverse the list. New elements can be added to the list before or
  71  * after an existing element, at the head of the list, or at the end of
  72  * the list. A tail queue may be traversed in either direction.
  73  *
  74  * A circle queue is headed by a pair of pointers, one to the head of the
  75  * list and the other to the tail of the list. The elements are doubly
  76  * linked so that an arbitrary element can be removed without a need to
  77  * traverse the list. New elements can be added to the list before or after
  78  * an existing element, at the head of the list, or at the end of the list.
  79  * A circle queue may be traversed in either direction, but has a more
  80  * complex end of list detection.
  81  *
  82  * For details on the use of these macros, see the queue(3) manual page.
  83  */
  84
  85 #if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
  86 #define _Q_INVALIDATE(a) (a) = ((void *)-1)
  87 #else
  88 #define _Q_INVALIDATE(a)
  89 #endif
  90
  91 /*
  92  * Singly-linked List definitions.
  93  */
  94 #define SLIST_HEAD(name, type)                                          \
  95 struct name {                                                           \
  96         struct type *slh_first; /* first element */                     \
  97 }
  98
  99 #define SLIST_HEAD_INITIALIZER(head)                                    \
 100         { NULL }
 101
 102 #define SLIST_ENTRY(type)                                               \
 103 struct {                                                                \
 104         struct type *sle_next;  /* next element */                      \
 105 }
 106
 107 /*
 108  * Singly-linked List access methods.
 109  */
 110 #define SLIST_FIRST(head)       ((head)->slh_first)
 111 #define SLIST_END(head)         NULL
 112 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 113 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 114
 115 #define SLIST_FOREACH(var, head, field)                                 \
 116         for((var) = SLIST_FIRST(head);                                  \
 117             (var) != SLIST_END(head);                                   \
 118             (var) = SLIST_NEXT(var, field))
 119
 120 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 121         for ((var) = SLIST_FIRST(head);                         \
 122             (var) && ((tvar) = SLIST_NEXT(var, field), 1);              \
 123             (var) = (tvar))
 124
 125 /*
 126  * Singly-linked List functions.
 127  */
 128 #define SLIST_INIT(head) {                                              \
 129         SLIST_FIRST(head) = SLIST_END(head);                            \
 130 }
 131
 132 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 133         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 134         (slistelm)->field.sle_next = (elm);                             \
 135 } while (0)
 136
 137 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 138         (elm)->field.sle_next = (head)->slh_first;                      \
 139         (head)->slh_first = (elm);                                      \
 140 } while (0)
 141
 142 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 143         (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;  \
 144 } while (0)
 145
 146 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 147         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 148 } while (0)
 149
 150 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 151         if ((head)->slh_first == (elm)) {                               \
 152                 SLIST_REMOVE_HEAD((head), field);                       \
 153         } else {                                                        \
 154                 struct type *curelm = (head)->slh_first;                \
 155                                                                         \
 156                 while (curelm->field.sle_next != (elm))                 \
 157                         curelm = curelm->field.sle_next;                \
 158                 curelm->field.sle_next =                                \
 159                     curelm->field.sle_next->field.sle_next;             \
 160                 _Q_INVALIDATE((elm)->field.sle_next);                   \
 161         }                                                               \
 162 } while (0)
 163
 164 #define SLIST_SWAP(head1, head2, type) do {                             \
 165         struct type *swap_first = SLIST_FIRST(head1);                   \
 166         SLIST_FIRST(head1) = SLIST_FIRST(head2);                        \
 167         SLIST_FIRST(head2) = swap_first;                                \
 168 } while (0)
 169
 170 /*
 171  * List definitions.
 172  */
 173 #define LIST_HEAD(name, type)                                           \
 174 struct name {                                                           \
 175         struct type *lh_first;  /* first element */                     \
 176 }
 177
 178 #define LIST_HEAD_INITIALIZER(head)                                     \
 179         { NULL }
 180
 181 #define LIST_ENTRY(type)                                                \
 182 struct {                                                                \
 183         struct type *le_next;   /* next element */                      \
 184         struct type **le_prev;  /* address of previous next element */  \
 185 }
 186
 187 /*
 188  * List access methods
 189  */
 190 #define LIST_FIRST(head)                ((head)->lh_first)
 191 #define LIST_END(head)                  NULL
 192 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 193 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 194
 195 #define LIST_FOREACH(var, head, field)                                  \
 196         for((var) = LIST_FIRST(head);                                   \
 197             (var)!= LIST_END(head);                                     \
 198             (var) = LIST_NEXT(var, field))
 199
 200 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 201         for ((var) = LIST_FIRST(head);                          \
 202             (var) && ((tvar) = LIST_NEXT(var, field), 1);               \
 203             (var) = (tvar))
 204
 205 /*
 206  * List functions.
 207  */
 208 #define LIST_INIT(head) do {                                            \
 209         LIST_FIRST(head) = LIST_END(head);                              \
 210 } while (0)
 211
 212 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 213         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 214                 (listelm)->field.le_next->field.le_prev =               \
 215                     &(elm)->field.le_next;                              \
 216         (listelm)->field.le_next = (elm);                               \
 217         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 218 } while (0)
 219
 220 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 221         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 222         (elm)->field.le_next = (listelm);                               \
 223         *(listelm)->field.le_prev = (elm);                              \
 224         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 225 } while (0)
 226
 227 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 228         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 229                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 230         (head)->lh_first = (elm);                                       \
 231         (elm)->field.le_prev = &(head)->lh_first;                       \
 232 } while (0)
 233
 234 #define LIST_REMOVE(elm, field) do {                                    \
 235         if ((elm)->field.le_next != NULL)                               \
 236                 (elm)->field.le_next->field.le_prev =                   \
 237                     (elm)->field.le_prev;                               \
 238         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 239         _Q_INVALIDATE((elm)->field.le_prev);                            \
 240         _Q_INVALIDATE((elm)->field.le_next);                            \
 241 } while (0)
 242
 243 #define LIST_REPLACE(elm, elm2, field) do {                             \
 244         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 245                 (elm2)->field.le_next->field.le_prev =                  \
 246                     &(elm2)->field.le_next;                             \
 247         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 248         *(elm2)->field.le_prev = (elm2);                                \
 249         _Q_INVALIDATE((elm)->field.le_prev);                            \
 250         _Q_INVALIDATE((elm)->field.le_next);                            \
 251 } while (0)
 252
 253 #define LIST_SWAP(head1, head2, type, field) do {                       \
 254         struct type *swap_tmp = LIST_FIRST((head1));                    \
 255         LIST_FIRST((head1)) = LIST_FIRST((head2));                      \
 256         LIST_FIRST((head2)) = swap_tmp;                                 \
 257         if ((swap_tmp = LIST_FIRST((head1))) != NULL)                   \
 258                 swap_tmp->field.le_prev = &LIST_FIRST((head1));         \
 259         if ((swap_tmp = LIST_FIRST((head2))) != NULL)                   \
 260                 swap_tmp->field.le_prev = &LIST_FIRST((head2));         \
 261 } while (0)
 262
 263 /*
 264  * Simple queue definitions.
 265  */
 266 #define SIMPLEQ_HEAD(name, type)                                        \
 267 struct name {                                                           \
 268         struct type *sqh_first; /* first element */                     \
 269         struct type **sqh_last; /* addr of last next element */         \
 270 }
 271
 272 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 273         { NULL, &(head).sqh_first }
 274
 275 #define SIMPLEQ_ENTRY(type)                                             \
 276 struct {                                                                \
 277         struct type *sqe_next;  /* next element */                      \
 278 }
 279
 280 /*
 281  * Simple queue access methods.
 282  */
 283 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 284 #define SIMPLEQ_END(head)           NULL
 285 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 286 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 287
 288 #define SIMPLEQ_FOREACH(var, head, field)                               \
 289         for((var) = SIMPLEQ_FIRST(head);                                \
 290             (var) != SIMPLEQ_END(head);                                 \
 291             (var) = SIMPLEQ_NEXT(var, field))
 292
 293 #define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 294         for ((var) = SIMPLEQ_FIRST(head);                               \
 295             (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1);            \
 296             (var) = (tvar))
 297
 298 /*
 299  * Simple queue functions.
 300  */
 301 #define SIMPLEQ_INIT(head) do {                                         \
 302         (head)->sqh_first = NULL;                                       \
 303         (head)->sqh_last = &(head)->sqh_first;                          \
 304 } while (0)
 305
 306 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 307         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 308                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 309         (head)->sqh_first = (elm);                                      \
 310 } while (0)
 311
 312 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 313         (elm)->field.sqe_next = NULL;                                   \
 314         *(head)->sqh_last = (elm);                                      \
 315         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 316 } while (0)
 317
 318 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 319         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 320                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 321         (listelm)->field.sqe_next = (elm);                              \
 322 } while (0)
 323
 324 #define SIMPLEQ_REMOVE_HEAD(head, field) do {                   \
 325         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 326                 (head)->sqh_last = &(head)->sqh_first;                  \
 327 } while (0)
 328
 329 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {                     \
 330         if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
 331             == NULL)                                                    \
 332                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 333 } while (0)
 334
 335 /*
 336  * XOR Simple queue definitions.
 337  */
 338 #define XSIMPLEQ_HEAD(name, type)                                       \
 339 struct name {                                                           \
 340         struct type *sqx_first; /* first element */                     \
 341         struct type **sqx_last; /* addr of last next element */         \
 342         unsigned long sqx_cookie;                                       \
 343 }
 344
 345 #define XSIMPLEQ_ENTRY(type)                                            \
 346 struct {                                                                \
 347         struct type *sqx_next;  /* next element */                      \
 348 }
 349
 350 /*
 351  * XOR Simple queue access methods.
 352  */
 353 #define XSIMPLEQ_XOR(head, ptr)     ((__typeof(ptr))((head)->sqx_cookie ^ \
 354                                         (unsigned long)(ptr)))
 355 #define XSIMPLEQ_FIRST(head)        XSIMPLEQ_XOR(head, ((head)->sqx_first))
 356 #define XSIMPLEQ_END(head)          NULL
 357 #define XSIMPLEQ_EMPTY(head)        (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head))
 358 #define XSIMPLEQ_NEXT(head, elm, field)    XSIMPLEQ_XOR(head, ((elm)->field.sqx_next))
 359
 360
 361 #define XSIMPLEQ_FOREACH(var, head, field)                              \
 362         for ((var) = XSIMPLEQ_FIRST(head);                              \
 363             (var) != XSIMPLEQ_END(head);                                \
 364             (var) = XSIMPLEQ_NEXT(head, var, field))
 365
 366 #define XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar)                   \
 367         for ((var) = XSIMPLEQ_FIRST(head);                              \
 368             (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1);     \
 369             (var) = (tvar))
 370
 371 /*
 372  * XOR Simple queue functions.
 373  */
 374 #define XSIMPLEQ_INIT(head) do {                                        \
 375         arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \
 376         (head)->sqx_first = XSIMPLEQ_XOR(head, NULL);                   \
 377         (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first);      \
 378 } while (0)
 379
 380 #define XSIMPLEQ_INSERT_HEAD(head, elm, field) do {                     \
 381         if (((elm)->field.sqx_next = (head)->sqx_first) ==              \
 382             XSIMPLEQ_XOR(head, NULL))                                   \
 383                 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
 384         (head)->sqx_first = XSIMPLEQ_XOR(head, (elm));                  \
 385 } while (0)
 386
 387 #define XSIMPLEQ_INSERT_TAIL(head, elm, field) do {                     \
 388         (elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL);               \
 389         *(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \
 390         (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next);  \
 391 } while (0)
 392
 393 #define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
 394         if (((elm)->field.sqx_next = (listelm)->field.sqx_next) ==      \
 395             XSIMPLEQ_XOR(head, NULL))                                   \
 396                 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
 397         (listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm));          \
 398 } while (0)
 399
 400 #define XSIMPLEQ_REMOVE_HEAD(head, field) do {                          \
 401         if (((head)->sqx_first = XSIMPLEQ_XOR(head,                     \
 402             (head)->sqx_first)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \
 403                 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
 404 } while (0)
 405
 406 #define XSIMPLEQ_REMOVE_AFTER(head, elm, field) do {                    \
 407         if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head,                 \
 408             (elm)->field.sqx_next)->field.sqx_next)                     \
 409             == XSIMPLEQ_XOR(head, NULL))                                \
 410                 (head)->sqx_last =                                      \
 411                     XSIMPLEQ_XOR(head, &(elm)->field.sqx_next);         \
 412 } while (0)
 413
 414
 415 /*
 416  * Tail queue definitions.
 417  */
 418 #define TAILQ_HEAD(name, type)                                          \
 419 struct name {                                                           \
 420         struct type *tqh_first; /* first element */                     \
 421         struct type **tqh_last; /* addr of last next element */         \
 422 }
 423
 424 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 425         { NULL, &(head).tqh_first }
 426
 427 #define TAILQ_ENTRY(type)                                               \
 428 struct {                                                                \
 429         struct type *tqe_next;  /* next element */                      \
 430         struct type **tqe_prev; /* address of previous next element */  \
 431 }
 432
 433 /*
 434  * tail queue access methods
 435  */
 436 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 437 #define TAILQ_END(head)                 NULL
 438 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 439 #define TAILQ_LAST(head, headname)                                      \
 440         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 441 /* XXX */
 442 #define TAILQ_PREV(elm, headname, field)                                \
 443         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 444 #define TAILQ_EMPTY(head)                                               \
 445         (TAILQ_FIRST(head) == TAILQ_END(head))
 446
 447 #define TAILQ_FOREACH(var, head, field)                                 \
 448         for((var) = TAILQ_FIRST(head);                                  \
 449             (var) != TAILQ_END(head);                                   \
 450             (var) = TAILQ_NEXT(var, field))
 451
 452 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 453         for ((var) = TAILQ_FIRST(head);                                 \
 454             (var) != TAILQ_END(head) &&                                 \
 455             ((tvar) = TAILQ_NEXT(var, field), 1);                       \
 456             (var) = (tvar))
 457
 458
 459 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 460         for((var) = TAILQ_LAST(head, headname);                         \
 461             (var) != TAILQ_END(head);                                   \
 462             (var) = TAILQ_PREV(var, headname, field))
 463
 464 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 465         for ((var) = TAILQ_LAST(head, headname);                        \
 466             (var) != TAILQ_END(head) &&                                 \
 467             ((tvar) = TAILQ_PREV(var, headname, field), 1);             \
 468             (var) = (tvar))
 469
 470 /*
 471  * Tail queue functions.
 472  */
 473 #define TAILQ_INIT(head) do {                                           \
 474         (head)->tqh_first = NULL;                                       \
 475         (head)->tqh_last = &(head)->tqh_first;                          \
 476 } while (0)
 477
 478 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 479         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 480                 (head)->tqh_first->field.tqe_prev =                     \
 481                     &(elm)->field.tqe_next;                             \
 482         else                                                            \
 483                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 484         (head)->tqh_first = (elm);                                      \
 485         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 486 } while (0)
 487
 488 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 489         (elm)->field.tqe_next = NULL;                                   \
 490         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 491         *(head)->tqh_last = (elm);                                      \
 492         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 493 } while (0)
 494
 495 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 496         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 497                 (elm)->field.tqe_next->field.tqe_prev =                 \
 498                     &(elm)->field.tqe_next;                             \
 499         else                                                            \
 500                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 501         (listelm)->field.tqe_next = (elm);                              \
 502         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 503 } while (0)
 504
 505 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 506         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 507         (elm)->field.tqe_next = (listelm);                              \
 508         *(listelm)->field.tqe_prev = (elm);                             \
 509         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 510 } while (0)
 511
 512 #define TAILQ_REMOVE(head, elm, field) do {                             \
 513         if (((elm)->field.tqe_next) != NULL)                            \
 514                 (elm)->field.tqe_next->field.tqe_prev =                 \
 515                     (elm)->field.tqe_prev;                              \
 516         else                                                            \
 517                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 518         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 519         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 520         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 521 } while (0)
 522
 523 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 524         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 525                 (elm2)->field.tqe_next->field.tqe_prev =                \
 526                     &(elm2)->field.tqe_next;                            \
 527         else                                                            \
 528                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 529         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 530         *(elm2)->field.tqe_prev = (elm2);                               \
 531         _Q_INVALIDATE((elm)->field.tqe_prev);                           \
 532         _Q_INVALIDATE((elm)->field.tqe_next);                           \
 533 } while (0)
 534
 535 #define TAILQ_SWAP(head1, head2, type, field) do {                      \
 536         struct type *swap_first = (head1)->tqh_first;                   \
 537         struct type **swap_last = (head1)->tqh_last;                    \
 538         (head1)->tqh_first = (head2)->tqh_first;                        \
 539         (head1)->tqh_last = (head2)->tqh_last;                          \
 540         (head2)->tqh_first = swap_first;                                \
 541         (head2)->tqh_last = swap_last;                                  \
 542         if ((swap_first = (head1)->tqh_first) != NULL)                  \
 543                 swap_first->field.tqe_prev = &(head1)->tqh_first;       \
 544         else                                                            \
 545                 (head1)->tqh_last = &(head1)->tqh_first;                \
 546         if ((swap_first = (head2)->tqh_first) != NULL)                  \
 547                 swap_first->field.tqe_prev = &(head2)->tqh_first;       \
 548         else                                                            \
 549                 (head2)->tqh_last = &(head2)->tqh_first;                \
 550 } while (0)
 551
 552 /*
 553  * Circular queue definitions.
 554  */
 555 #define CIRCLEQ_HEAD(name, type)                                        \
 556 struct name {                                                           \
 557         struct type *cqh_first;         /* first element */             \
 558         struct type *cqh_last;          /* last element */              \
 559 }
 560
 561 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 562         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 563
 564 #define CIRCLEQ_ENTRY(type)                                             \
 565 struct {                                                                \
 566         struct type *cqe_next;          /* next element */              \
 567         struct type *cqe_prev;          /* previous element */          \
 568 }
 569
 570 /*
 571  * Circular queue access methods
 572  */
 573 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 574 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 575 #define CIRCLEQ_END(head)               ((void *)(head))
 576 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 577 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 578 #define CIRCLEQ_EMPTY(head)                                             \
 579         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 580
 581 #define CIRCLEQ_FOREACH(var, head, field)                               \
 582         for((var) = CIRCLEQ_FIRST(head);                                \
 583             (var) != CIRCLEQ_END(head);                                 \
 584             (var) = CIRCLEQ_NEXT(var, field))
 585
 586 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar)                    \
 587         for ((var) = CIRCLEQ_FIRST(head);                               \
 588             (var) != CIRCLEQ_END(head) &&                               \
 589             ((tvar) = CIRCLEQ_NEXT(var, field), 1);                     \
 590             (var) = (tvar))
 591
 592 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 593         for((var) = CIRCLEQ_LAST(head);                                 \
 594             (var) != CIRCLEQ_END(head);                                 \
 595             (var) = CIRCLEQ_PREV(var, field))
 596
 597 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)  \
 598         for ((var) = CIRCLEQ_LAST(head, headname);                      \
 599             (var) != CIRCLEQ_END(head) &&                               \
 600             ((tvar) = CIRCLEQ_PREV(var, headname, field), 1);           \
 601             (var) = (tvar))
 602
 603 /*
 604  * Circular queue functions.
 605  */
 606 #define CIRCLEQ_INIT(head) do {                                         \
 607         (head)->cqh_first = CIRCLEQ_END(head);                          \
 608         (head)->cqh_last = CIRCLEQ_END(head);                           \
 609 } while (0)
 610
 611 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 612         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 613         (elm)->field.cqe_prev = (listelm);                              \
 614         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 615                 (head)->cqh_last = (elm);                               \
 616         else                                                            \
 617                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 618         (listelm)->field.cqe_next = (elm);                              \
 619 } while (0)
 620
 621 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 622         (elm)->field.cqe_next = (listelm);                              \
 623         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 624         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 625                 (head)->cqh_first = (elm);                              \
 626         else                                                            \
 627                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 628         (listelm)->field.cqe_prev = (elm);                              \
 629 } while (0)
 630
 631 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 632         (elm)->field.cqe_next = (head)->cqh_first;                      \
 633         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 634         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 635                 (head)->cqh_last = (elm);                               \
 636         else                                                            \
 637                 (head)->cqh_first->field.cqe_prev = (elm);              \
 638         (head)->cqh_first = (elm);                                      \
 639 } while (0)
 640
 641 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 642         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 643         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 644         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 645                 (head)->cqh_first = (elm);                              \
 646         else                                                            \
 647                 (head)->cqh_last->field.cqe_next = (elm);               \
 648         (head)->cqh_last = (elm);                                       \
 649 } while (0)
 650
 651 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 652         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 653                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 654         else                                                            \
 655                 (elm)->field.cqe_next->field.cqe_prev =                 \
 656                     (elm)->field.cqe_prev;                              \
 657         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 658                 (head)->cqh_first = (elm)->field.cqe_next;              \
 659         else                                                            \
 660                 (elm)->field.cqe_prev->field.cqe_next =                 \
 661                     (elm)->field.cqe_next;                              \
 662         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 663         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 664 } while (0)
 665
 666 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 667         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 668             CIRCLEQ_END(head))                                          \
 669                 (head)->cqh_last = (elm2);                              \
 670         else                                                            \
 671                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 672         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 673             CIRCLEQ_END(head))                                          \
 674                 (head)->cqh_first = (elm2);                             \
 675         else                                                            \
 676                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 677         _Q_INVALIDATE((elm)->field.cqe_prev);                           \
 678         _Q_INVALIDATE((elm)->field.cqe_next);                           \
 679 } while (0)
 680
 681 #endif  /* !_SYS_QUEUE_H_ */