git.sur5r.net Git - openldap/blob - include/ldap_queue.h

   1 /* ldap_queue.h -- queue macros */
   2 /* $OpenLDAP$ */
   3 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   4  *
   5  * Copyright 2001-2018 The OpenLDAP Foundation.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted only as authorized by the OpenLDAP
  10  * Public License.
  11  *
  12  * A copy of this license is available in file LICENSE in the
  13  * top-level directory of the distribution or, alternatively, at
  14  * <http://www.OpenLDAP.org/license.html>.
  15  */
  16 /* Copyright (c) 1991, 1993
  17  *      The Regents of the University of California.  All rights reserved.
  18  *
  19  * Redistribution and use in source and binary forms, with or without
  20  * modification, are permitted provided that the following conditions
  21  * are met:
  22  * 1. Redistributions of source code must retain the above copyright
  23  *    notice, this list of conditions and the following disclaimer.
  24  * 2. Redistributions in binary form must reproduce the above copyright
  25  *    notice, this list of conditions and the following disclaimer in the
  26  *    documentation and/or other materials provided with the distribution.
  27  * 3. All advertising materials mentioning features or use of this software
  28  *    must display the following acknowledgement:
  29  *      This product includes software developed by the University of
  30  *      California, Berkeley and its contributors.
  31  * 4. Neither the name of the University nor the names of its contributors
  32  *    may be used to endorse or promote products derived from this software
  33  *    without specific prior written permission.
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  36  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  38  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  39  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  40  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  41  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  42  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  43  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  44  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  45  * SUCH DAMAGE.
  46  *
  47  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  48  * $FreeBSD: src/sys/sys/queue.h,v 1.32.2.5 2001/09/30 21:12:54 luigi Exp $
  49  *
  50  * See also: ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
  51  */
  52 /* ACKNOWLEDGEMENTS:
  53  * This work is derived from FreeBSD queue.h work.  Adapted for use in
  54  * OpenLDAP Software by Kurt D. Zeilenga.
  55  */
  56
  57 #ifndef _LDAP_QUEUE_H_
  58 #define _LDAP_QUEUE_H_
  59
  60 /*
  61  * This file defines five types of data structures: singly-linked lists,
  62  * singly-linked tail queues, lists, tail queues, and circular queues.
  63  *
  64  * A singly-linked list is headed by a single forward pointer. The elements
  65  * are singly linked for minimum space and pointer manipulation overhead at
  66  * the expense of O(n) removal for arbitrary elements. New elements can be
  67  * added to the list after an existing element or at the head of the list.
  68  * Elements being removed from the head of the list should use the explicit
  69  * macro for this purpose for optimum efficiency. A singly-linked list may
  70  * only be traversed in the forward direction.  Singly-linked lists are ideal
  71  * for applications with large datasets and few or no removals or for
  72  * implementing a LIFO queue.
  73  *
  74  * A singly-linked tail queue is headed by a pair of pointers, one to the
  75  * head of the list and the other to the tail of the list. The elements are
  76  * singly linked for minimum space and pointer manipulation overhead at the
  77  * expense of O(n) removal for arbitrary elements. New elements can be added
  78  * to the list after an existing element, at the head of the list, or at the
  79  * end of the list. Elements being removed from the head of the tail queue
  80  * should use the explicit macro for this purpose for optimum efficiency.
  81  * A singly-linked tail queue may only be traversed in the forward direction.
  82  * Singly-linked tail queues are ideal for applications with large datasets
  83  * and few or no removals or for implementing a FIFO queue.
  84  *
  85  * A list is headed by a single forward pointer (or an array of forward
  86  * pointers for a hash table header). The elements are doubly linked
  87  * so that an arbitrary element can be removed without a need to
  88  * traverse the list. New elements can be added to the list before
  89  * or after an existing element or at the head of the list. A list
  90  * may only be traversed in the forward direction.
  91  *
  92  * A tail queue is headed by a pair of pointers, one to the head of the
  93  * list and the other to the tail of the list. The elements are doubly
  94  * linked so that an arbitrary element can be removed without a need to
  95  * traverse the list. New elements can be added to the list before or
  96  * after an existing element, at the head of the list, or at the end of
  97  * the list. A tail queue may be traversed in either direction.
  98  *
  99  * A circle queue is headed by a pair of pointers, one to the head of the
 100  * list and the other to the tail of the list. The elements are doubly
 101  * linked so that an arbitrary element can be removed without a need to
 102  * traverse the list. New elements can be added to the list before or after
 103  * an existing element, at the head of the list, or at the end of the list.
 104  * A circle queue may be traversed in either direction, but has a more
 105  * complex end of list detection. Also, it is possible to rotate the queue,
 106  * rejoining the ends and splitting it so that a given element becomes the
 107  * new head or tail.
 108  *
 109  * For details on the use of these macros, see the queue(3) manual page.
 110  * All macros are prefixed with LDAP_.
 111  *
 112  *                      SLIST_  LIST_   STAILQ_ TAILQ_  CIRCLEQ_
 113  * _HEAD                +       +       +       +       +
 114  * _ENTRY               +       +       +       +       +
 115  * _INIT                +       +       +       +       +
 116  * _ENTRY_INIT          +       +       +       +       +
 117  * _EMPTY               +       +       +       +       +
 118  * _FIRST               +       +       +       +       +
 119  * _NEXT                +       +       +       +       +
 120  * _PREV                -       -       -       +       +
 121  * _LAST                -       -       +       +       +
 122  * _FOREACH             +       +       +       +       +
 123  * _FOREACH_REVERSE     -       -       -       +       +
 124  * _INSERT_HEAD         +       +       +       +       +
 125  * _INSERT_BEFORE       -       +       -       +       +
 126  * _INSERT_AFTER        +       +       +       +       +
 127  * _INSERT_TAIL         -       -       +       +       +
 128  * _REMOVE_HEAD         +       -       +       -       -
 129  * _REMOVE              +       +       +       +       +
 130  *
 131  */
 132
 133 /*
 134  * Singly-linked List definitions.
 135  */
 136 #define LDAP_SLIST_HEAD(name, type)                                     \
 137 struct name {                                                           \
 138         struct type *slh_first; /* first element */                     \
 139 }
 140
 141 #define LDAP_SLIST_HEAD_INITIALIZER(head)                               \
 142         { NULL }
 143
 144 #define LDAP_SLIST_ENTRY(type)                                          \
 145 struct {                                                                \
 146         struct type *sle_next;  /* next element */                      \
 147 }
 148
 149 #define LDAP_SLIST_ENTRY_INITIALIZER(entry)                             \
 150         { NULL }
 151
 152 /*
 153  * Singly-linked List functions.
 154  */
 155 #define LDAP_SLIST_EMPTY(head)  ((head)->slh_first == NULL)
 156
 157 #define LDAP_SLIST_FIRST(head)  ((head)->slh_first)
 158
 159 #define LDAP_SLIST_FOREACH(var, head, field)                            \
 160         for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
 161
 162 #define LDAP_SLIST_INIT(head) {                                         \
 163         (head)->slh_first = NULL;                                       \
 164 }
 165
 166 #define LDAP_SLIST_ENTRY_INIT(var, field) {                             \
 167         (var)->field.sle_next = NULL;                                   \
 168 }
 169
 170 #define LDAP_SLIST_INSERT_AFTER(slistelm, elm, field) do {              \
 171         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 172         (slistelm)->field.sle_next = (elm);                             \
 173 } while (0)
 174
 175 #define LDAP_SLIST_INSERT_HEAD(head, elm, field) do {                   \
 176         (elm)->field.sle_next = (head)->slh_first;                      \
 177         (head)->slh_first = (elm);                                      \
 178 } while (0)
 179
 180 #define LDAP_SLIST_NEXT(elm, field)     ((elm)->field.sle_next)
 181
 182 #define LDAP_SLIST_REMOVE_HEAD(head, field) do {                        \
 183         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 184 } while (0)
 185
 186 #define LDAP_SLIST_REMOVE(head, elm, type, field) do {                  \
 187         if ((head)->slh_first == (elm)) {                               \
 188                 LDAP_SLIST_REMOVE_HEAD((head), field);                  \
 189         }                                                               \
 190         else {                                                          \
 191                 struct type *curelm = (head)->slh_first;                \
 192                 while( curelm->field.sle_next != (elm) )                \
 193                         curelm = curelm->field.sle_next;                \
 194                 curelm->field.sle_next =                                \
 195                     curelm->field.sle_next->field.sle_next;             \
 196         }                                                               \
 197 } while (0)
 198
 199 /*
 200  * Singly-linked Tail queue definitions.
 201  */
 202 #define LDAP_STAILQ_HEAD(name, type)                                    \
 203 struct name {                                                           \
 204         struct type *stqh_first;/* first element */                     \
 205         struct type **stqh_last;/* addr of last next element */         \
 206 }
 207
 208 #define LDAP_STAILQ_HEAD_INITIALIZER(head)                              \
 209         { NULL, &(head).stqh_first }
 210
 211 #define LDAP_STAILQ_ENTRY(type)                                         \
 212 struct {                                                                \
 213         struct type *stqe_next; /* next element */                      \
 214 }
 215
 216 #define LDAP_STAILQ_ENTRY_INITIALIZER(entry)                            \
 217         { NULL }
 218
 219 /*
 220  * Singly-linked Tail queue functions.
 221  */
 222 #define LDAP_STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
 223
 224 #define LDAP_STAILQ_INIT(head) do {                                     \
 225         (head)->stqh_first = NULL;                                      \
 226         (head)->stqh_last = &(head)->stqh_first;                        \
 227 } while (0)
 228
 229 #define LDAP_STAILQ_ENTRY_INIT(var, field) {                            \
 230         (var)->field.stqe_next = NULL;                                  \
 231 }
 232
 233 #define LDAP_STAILQ_FIRST(head) ((head)->stqh_first)
 234
 235 #define LDAP_STAILQ_LAST(head, type, field)                             \
 236         (LDAP_STAILQ_EMPTY(head) ?                                      \
 237                 NULL :                                                  \
 238                 ((struct type *)                                        \
 239                 ((char *)((head)->stqh_last) - offsetof(struct type, field))))
 240
 241 #define LDAP_STAILQ_FOREACH(var, head, field)                           \
 242         for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next)
 243
 244 #define LDAP_STAILQ_INSERT_HEAD(head, elm, field) do {                  \
 245         if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
 246                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 247         (head)->stqh_first = (elm);                                     \
 248 } while (0)
 249
 250 #define LDAP_STAILQ_INSERT_TAIL(head, elm, field) do {                  \
 251         (elm)->field.stqe_next = NULL;                                  \
 252         *(head)->stqh_last = (elm);                                     \
 253         (head)->stqh_last = &(elm)->field.stqe_next;                    \
 254 } while (0)
 255
 256 #define LDAP_STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {          \
 257         if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
 258                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 259         (tqelm)->field.stqe_next = (elm);                               \
 260 } while (0)
 261
 262 #define LDAP_STAILQ_NEXT(elm, field)    ((elm)->field.stqe_next)
 263
 264 #define LDAP_STAILQ_REMOVE_HEAD(head, field) do {                       \
 265         if (((head)->stqh_first =                                       \
 266              (head)->stqh_first->field.stqe_next) == NULL)              \
 267                 (head)->stqh_last = &(head)->stqh_first;                \
 268 } while (0)
 269
 270 #define LDAP_STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {            \
 271         if (((head)->stqh_first = (elm)->field.stqe_next) == NULL)      \
 272                 (head)->stqh_last = &(head)->stqh_first;                \
 273 } while (0)
 274
 275 #define LDAP_STAILQ_REMOVE(head, elm, type, field) do {                 \
 276         if ((head)->stqh_first == (elm)) {                              \
 277                 LDAP_STAILQ_REMOVE_HEAD(head, field);                   \
 278         }                                                               \
 279         else {                                                          \
 280                 struct type *curelm = (head)->stqh_first;               \
 281                 while( curelm->field.stqe_next != (elm) )               \
 282                         curelm = curelm->field.stqe_next;               \
 283                 if((curelm->field.stqe_next =                           \
 284                     curelm->field.stqe_next->field.stqe_next) == NULL)  \
 285                         (head)->stqh_last = &(curelm)->field.stqe_next; \
 286         }                                                               \
 287 } while (0)
 288
 289 /*
 290  * List definitions.
 291  */
 292 #define LDAP_LIST_HEAD(name, type)                                      \
 293 struct name {                                                           \
 294         struct type *lh_first;  /* first element */                     \
 295 }
 296
 297 #define LDAP_LIST_HEAD_INITIALIZER(head)                                \
 298         { NULL }
 299
 300 #define LDAP_LIST_ENTRY(type)                                           \
 301 struct {                                                                \
 302         struct type *le_next;   /* next element */                      \
 303         struct type **le_prev;  /* address of previous next element */  \
 304 }
 305
 306 #define LDAP_LIST_ENTRY_INITIALIZER(entry)                      \
 307         { NULL, NULL }
 308
 309 /*
 310  * List functions.
 311  */
 312
 313 #define LDAP_LIST_EMPTY(head) ((head)->lh_first == NULL)
 314
 315 #define LDAP_LIST_FIRST(head)   ((head)->lh_first)
 316
 317 #define LDAP_LIST_FOREACH(var, head, field)                             \
 318         for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
 319
 320 #define LDAP_LIST_INIT(head) do {                                       \
 321         (head)->lh_first = NULL;                                        \
 322 } while (0)
 323
 324 #define LDAP_LIST_ENTRY_INIT(var, field) do {                           \
 325         (var)->field.le_next = NULL;                                    \
 326         (var)->field.le_prev = NULL;                                    \
 327 } while (0)
 328
 329 #define LDAP_LIST_INSERT_AFTER(listelm, elm, field) do {                \
 330         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 331                 (listelm)->field.le_next->field.le_prev =               \
 332                     &(elm)->field.le_next;                              \
 333         (listelm)->field.le_next = (elm);                               \
 334         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 335 } while (0)
 336
 337 #define LDAP_LIST_INSERT_BEFORE(listelm, elm, field) do {               \
 338         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 339         (elm)->field.le_next = (listelm);                               \
 340         *(listelm)->field.le_prev = (elm);                              \
 341         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 342 } while (0)
 343
 344 #define LDAP_LIST_INSERT_HEAD(head, elm, field) do {                    \
 345         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 346                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 347         (head)->lh_first = (elm);                                       \
 348         (elm)->field.le_prev = &(head)->lh_first;                       \
 349 } while (0)
 350
 351 #define LDAP_LIST_NEXT(elm, field)      ((elm)->field.le_next)
 352
 353 #define LDAP_LIST_REMOVE(elm, field) do {                               \
 354         if ((elm)->field.le_next != NULL)                               \
 355                 (elm)->field.le_next->field.le_prev =                   \
 356                     (elm)->field.le_prev;                               \
 357         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 358 } while (0)
 359
 360 /*
 361  * Tail queue definitions.
 362  */
 363 #define LDAP_TAILQ_HEAD(name, type)                                     \
 364 struct name {                                                           \
 365         struct type *tqh_first; /* first element */                     \
 366         struct type **tqh_last; /* addr of last next element */         \
 367 }
 368
 369 #define LDAP_TAILQ_HEAD_INITIALIZER(head)                               \
 370         { NULL, &(head).tqh_first }
 371
 372 #define LDAP_TAILQ_ENTRY(type)                                          \
 373 struct {                                                                \
 374         struct type *tqe_next;  /* next element */                      \
 375         struct type **tqe_prev; /* address of previous next element */  \
 376 }
 377
 378 #define LDAP_TAILQ_ENTRY_INITIALIZER(entry)                             \
 379         { NULL, NULL }
 380
 381 /*
 382  * Tail queue functions.
 383  */
 384 #define LDAP_TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
 385
 386 #define LDAP_TAILQ_FOREACH(var, head, field)                            \
 387         for (var = LDAP_TAILQ_FIRST(head); var; var = LDAP_TAILQ_NEXT(var, field))
 388
 389 #define LDAP_TAILQ_FOREACH_REVERSE(var, head, headname, field)          \
 390         for ((var) = LDAP_TAILQ_LAST((head), headname);                 \
 391              (var);                                                     \
 392              (var) = LDAP_TAILQ_PREV((var), headname, field))
 393
 394 #define LDAP_TAILQ_FIRST(head) ((head)->tqh_first)
 395
 396 #define LDAP_TAILQ_LAST(head, headname) \
 397         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 398
 399 #define LDAP_TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 400
 401 #define LDAP_TAILQ_PREV(elm, headname, field) \
 402         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 403
 404 #define LDAP_TAILQ_INIT(head) do {                                      \
 405         (head)->tqh_first = NULL;                                       \
 406         (head)->tqh_last = &(head)->tqh_first;                          \
 407 } while (0)
 408
 409 #define LDAP_TAILQ_ENTRY_INIT(var, field) do {                          \
 410         (var)->field.tqe_next = NULL;                                   \
 411         (var)->field.tqe_prev = NULL;                                   \
 412 } while (0)
 413
 414 #define LDAP_TAILQ_INSERT_HEAD(head, elm, field) do {                   \
 415         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 416                 (head)->tqh_first->field.tqe_prev =                     \
 417                     &(elm)->field.tqe_next;                             \
 418         else                                                            \
 419                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 420         (head)->tqh_first = (elm);                                      \
 421         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 422 } while (0)
 423
 424 #define LDAP_TAILQ_INSERT_TAIL(head, elm, field) do {                   \
 425         (elm)->field.tqe_next = NULL;                                   \
 426         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 427         *(head)->tqh_last = (elm);                                      \
 428         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 429 } while (0)
 430
 431 #define LDAP_TAILQ_INSERT_AFTER(head, listelm, elm, field) do {         \
 432         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 433                 (elm)->field.tqe_next->field.tqe_prev =                 \
 434                     &(elm)->field.tqe_next;                             \
 435         else                                                            \
 436                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 437         (listelm)->field.tqe_next = (elm);                              \
 438         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 439 } while (0)
 440
 441 #define LDAP_TAILQ_INSERT_BEFORE(listelm, elm, field) do {              \
 442         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 443         (elm)->field.tqe_next = (listelm);                              \
 444         *(listelm)->field.tqe_prev = (elm);                             \
 445         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 446 } while (0)
 447
 448 #define LDAP_TAILQ_REMOVE(head, elm, field) do {                        \
 449         if (((elm)->field.tqe_next) != NULL)                            \
 450                 (elm)->field.tqe_next->field.tqe_prev =                 \
 451                     (elm)->field.tqe_prev;                              \
 452         else                                                            \
 453                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 454         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 455 } while (0)
 456
 457 /*
 458  * Circular queue definitions.
 459  */
 460 #define LDAP_CIRCLEQ_HEAD(name, type)                                   \
 461 struct name {                                                           \
 462         struct type *cqh_first;         /* first element */             \
 463         struct type *cqh_last;          /* last element */              \
 464 }
 465
 466 #define LDAP_CIRCLEQ_HEAD_INITIALIZER(head)                             \
 467         { (void *)&(head), (void *)&(head) }
 468
 469 #define LDAP_CIRCLEQ_ENTRY(type)                                        \
 470 struct {                                                                \
 471         struct type *cqe_next;          /* next element */              \
 472         struct type *cqe_prev;          /* previous element */          \
 473 }
 474
 475 /*
 476  * Circular queue functions.
 477  */
 478 #define LDAP_CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 479
 480 #define LDAP_CIRCLEQ_FIRST(head) ((head)->cqh_first)
 481
 482 #define LDAP_CIRCLEQ_FOREACH(var, head, field)                          \
 483         for((var) = (head)->cqh_first;                                  \
 484             (var) != (void *)(head);                                    \
 485             (var) = (var)->field.cqe_next)
 486
 487 #define LDAP_CIRCLEQ_FOREACH_REVERSE(var, head, field)                  \
 488         for((var) = (head)->cqh_last;                                   \
 489             (var) != (void *)(head);                                    \
 490             (var) = (var)->field.cqe_prev)
 491
 492 #define LDAP_CIRCLEQ_INIT(head) do {                                    \
 493         (head)->cqh_first = (void *)(head);                             \
 494         (head)->cqh_last = (void *)(head);                              \
 495 } while (0)
 496
 497 #define LDAP_CIRCLEQ_ENTRY_INIT(var, field) do {                        \
 498         (var)->field.cqe_next = NULL;                                   \
 499         (var)->field.cqe_prev = NULL;                                   \
 500 } while (0)
 501
 502 #define LDAP_CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {       \
 503         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 504         (elm)->field.cqe_prev = (listelm);                              \
 505         if ((listelm)->field.cqe_next == (void *)(head))                \
 506                 (head)->cqh_last = (elm);                               \
 507         else                                                            \
 508                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 509         (listelm)->field.cqe_next = (elm);                              \
 510 } while (0)
 511
 512 #define LDAP_CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {      \
 513         (elm)->field.cqe_next = (listelm);                              \
 514         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 515         if ((listelm)->field.cqe_prev == (void *)(head))                \
 516                 (head)->cqh_first = (elm);                              \
 517         else                                                            \
 518                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 519         (listelm)->field.cqe_prev = (elm);                              \
 520 } while (0)
 521
 522 #define LDAP_CIRCLEQ_INSERT_HEAD(head, elm, field) do {                 \
 523         (elm)->field.cqe_next = (head)->cqh_first;                      \
 524         (elm)->field.cqe_prev = (void *)(head);                         \
 525         if ((head)->cqh_last == (void *)(head))                         \
 526                 (head)->cqh_last = (elm);                               \
 527         else                                                            \
 528                 (head)->cqh_first->field.cqe_prev = (elm);              \
 529         (head)->cqh_first = (elm);                                      \
 530 } while (0)
 531
 532 #define LDAP_CIRCLEQ_INSERT_TAIL(head, elm, field) do {                 \
 533         (elm)->field.cqe_next = (void *)(head);                         \
 534         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 535         if ((head)->cqh_first == (void *)(head))                        \
 536                 (head)->cqh_first = (elm);                              \
 537         else                                                            \
 538                 (head)->cqh_last->field.cqe_next = (elm);               \
 539         (head)->cqh_last = (elm);                                       \
 540 } while (0)
 541
 542 #define LDAP_CIRCLEQ_LAST(head) ((head)->cqh_last)
 543
 544 #define LDAP_CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
 545
 546 #define LDAP_CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
 547
 548 #define LDAP_CIRCLEQ_REMOVE(head, elm, field) do {                      \
 549         if ((elm)->field.cqe_next == (void *)(head))                    \
 550                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 551         else                                                            \
 552                 (elm)->field.cqe_next->field.cqe_prev =                 \
 553                     (elm)->field.cqe_prev;                              \
 554         if ((elm)->field.cqe_prev == (void *)(head))                    \
 555                 (head)->cqh_first = (elm)->field.cqe_next;              \
 556         else                                                            \
 557                 (elm)->field.cqe_prev->field.cqe_next =                 \
 558                     (elm)->field.cqe_next;                              \
 559 } while (0)
 560
 561 #define LDAP_CIRCLEQ_LOOP_NEXT(head, elm, field)                        \
 562         (((elm)->field.cqe_next == (void *)(head))                      \
 563                 ? ((head)->cqh_first)                                   \
 564                 : ((elm)->field.cqe_next))
 565
 566 #define LDAP_CIRCLEQ_LOOP_PREV(head, elm, field)                        \
 567         (((elm)->field.cqe_prev == (void *)(head))                      \
 568                 ? ((head)->cqh_last)                                    \
 569                 : ((elm)->field.cqe_prev))
 570
 571 #define LDAP_CIRCLEQ_MAKE_HEAD(head, elm, field) do {                   \
 572         if ((elm)->field.cqe_prev != (void *)(head)) {                  \
 573                 (head)->cqh_first->field.cqe_prev = (head)->cqh_last;   \
 574                 (head)->cqh_last->field.cqe_next = (head)->cqh_first;   \
 575                 (head)->cqh_first = elm;                                \
 576                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 577                 (elm)->field.cqe_prev->field.cqe_next = (void *)(head); \
 578                 (elm)->field.cqe_prev = (void *)(head);                 \
 579         }                                                               \
 580 } while (0)
 581
 582 #define LDAP_CIRCLEQ_MAKE_TAIL(head, elm, field) do {                   \
 583         if ((elm)->field.cqe_next != (void *)(head)) {                  \
 584                 (head)->cqh_first->field.cqe_prev = (head)->cqh_last;   \
 585                 (head)->cqh_last->field.cqe_next = (head)->cqh_first;   \
 586                 (head)->cqh_first = (elm)->field.cqe_next;              \
 587                 (head)->cqh_last = elm;                                 \
 588                 (elm)->field.cqe_next->field.cqe_prev = (void *)(head); \
 589                 (elm)->field.cqe_next = (void *)(head);                 \
 590         }                                                               \
 591 } while (0)
 592
 593 #endif /* !_LDAP_QUEUE_H_ */