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 2001-2017 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.
 106  *
 107  * For details on the use of these macros, see the queue(3) manual page.
 108  * All macros are prefixed with LDAP_.
 109  *
 110  *                      SLIST_  LIST_   STAILQ_ TAILQ_  CIRCLEQ_
 111  * _HEAD                +       +       +       +       +
 112  * _ENTRY               +       +       +       +       +
 113  * _INIT                +       +       +       +       +
 114  * _ENTRY_INIT          +       +       +       +       +
 115  * _EMPTY               +       +       +       +       +
 116  * _FIRST               +       +       +       +       +
 117  * _NEXT                +       +       +       +       +
 118  * _PREV                -       -       -       +       +
 119  * _LAST                -       -       +       +       +
 120  * _FOREACH             +       +       +       +       +
 121  * _FOREACH_REVERSE     -       -       -       +       +
 122  * _INSERT_HEAD         +       +       +       +       +
 123  * _INSERT_BEFORE       -       +       -       +       +
 124  * _INSERT_AFTER        +       +       +       +       +
 125  * _INSERT_TAIL         -       -       +       +       +
 126  * _REMOVE_HEAD         +       -       +       -       -
 127  * _REMOVE              +       +       +       +       +
 128  *
 129  */
 130
 131 /*
 132  * Singly-linked List definitions.
 133  */
 134 #define LDAP_SLIST_HEAD(name, type)                                     \
 135 struct name {                                                           \
 136         struct type *slh_first; /* first element */                     \
 137 }
 138
 139 #define LDAP_SLIST_HEAD_INITIALIZER(head)                               \
 140         { NULL }
 141
 142 #define LDAP_SLIST_ENTRY(type)                                          \
 143 struct {                                                                \
 144         struct type *sle_next;  /* next element */                      \
 145 }
 146
 147 #define LDAP_SLIST_ENTRY_INITIALIZER(entry)                             \
 148         { NULL }
 149
 150 /*
 151  * Singly-linked List functions.
 152  */
 153 #define LDAP_SLIST_EMPTY(head)  ((head)->slh_first == NULL)
 154
 155 #define LDAP_SLIST_FIRST(head)  ((head)->slh_first)
 156
 157 #define LDAP_SLIST_FOREACH(var, head, field)                            \
 158         for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
 159
 160 #define LDAP_SLIST_INIT(head) {                                         \
 161         (head)->slh_first = NULL;                                       \
 162 }
 163
 164 #define LDAP_SLIST_ENTRY_INIT(var, field) {                             \
 165         (var)->field.sle_next = NULL;                                   \
 166 }
 167
 168 #define LDAP_SLIST_INSERT_AFTER(slistelm, elm, field) do {              \
 169         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 170         (slistelm)->field.sle_next = (elm);                             \
 171 } while (0)
 172
 173 #define LDAP_SLIST_INSERT_HEAD(head, elm, field) do {                   \
 174         (elm)->field.sle_next = (head)->slh_first;                      \
 175         (head)->slh_first = (elm);                                      \
 176 } while (0)
 177
 178 #define LDAP_SLIST_NEXT(elm, field)     ((elm)->field.sle_next)
 179
 180 #define LDAP_SLIST_REMOVE_HEAD(head, field) do {                        \
 181         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 182 } while (0)
 183
 184 #define LDAP_SLIST_REMOVE(head, elm, type, field) do {                  \
 185         if ((head)->slh_first == (elm)) {                               \
 186                 LDAP_SLIST_REMOVE_HEAD((head), field);                  \
 187         }                                                               \
 188         else {                                                          \
 189                 struct type *curelm = (head)->slh_first;                \
 190                 while( curelm->field.sle_next != (elm) )                \
 191                         curelm = curelm->field.sle_next;                \
 192                 curelm->field.sle_next =                                \
 193                     curelm->field.sle_next->field.sle_next;             \
 194         }                                                               \
 195 } while (0)
 196
 197 /*
 198  * Singly-linked Tail queue definitions.
 199  */
 200 #define LDAP_STAILQ_HEAD(name, type)                                    \
 201 struct name {                                                           \
 202         struct type *stqh_first;/* first element */                     \
 203         struct type **stqh_last;/* addr of last next element */         \
 204 }
 205
 206 #define LDAP_STAILQ_HEAD_INITIALIZER(head)                              \
 207         { NULL, &(head).stqh_first }
 208
 209 #define LDAP_STAILQ_ENTRY(type)                                         \
 210 struct {                                                                \
 211         struct type *stqe_next; /* next element */                      \
 212 }
 213
 214 #define LDAP_STAILQ_ENTRY_INITIALIZER(entry)                            \
 215         { NULL }
 216
 217 /*
 218  * Singly-linked Tail queue functions.
 219  */
 220 #define LDAP_STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
 221
 222 #define LDAP_STAILQ_INIT(head) do {                                     \
 223         (head)->stqh_first = NULL;                                      \
 224         (head)->stqh_last = &(head)->stqh_first;                        \
 225 } while (0)
 226
 227 #define LDAP_STAILQ_ENTRY_INIT(var, field) {                            \
 228         (var)->field.stqe_next = NULL;                                  \
 229 }
 230
 231 #define LDAP_STAILQ_FIRST(head) ((head)->stqh_first)
 232
 233 #define LDAP_STAILQ_LAST(head, type, field)                             \
 234         (LDAP_STAILQ_EMPTY(head) ?                                      \
 235                 NULL :                                                  \
 236                 ((struct type *)                                        \
 237                 ((char *)((head)->stqh_last) - offsetof(struct type, field))))
 238
 239 #define LDAP_STAILQ_FOREACH(var, head, field)                           \
 240         for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next)
 241
 242 #define LDAP_STAILQ_INSERT_HEAD(head, elm, field) do {                  \
 243         if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
 244                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 245         (head)->stqh_first = (elm);                                     \
 246 } while (0)
 247
 248 #define LDAP_STAILQ_INSERT_TAIL(head, elm, field) do {                  \
 249         (elm)->field.stqe_next = NULL;                                  \
 250         *(head)->stqh_last = (elm);                                     \
 251         (head)->stqh_last = &(elm)->field.stqe_next;                    \
 252 } while (0)
 253
 254 #define LDAP_STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {          \
 255         if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
 256                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 257         (tqelm)->field.stqe_next = (elm);                               \
 258 } while (0)
 259
 260 #define LDAP_STAILQ_NEXT(elm, field)    ((elm)->field.stqe_next)
 261
 262 #define LDAP_STAILQ_REMOVE_HEAD(head, field) do {                       \
 263         if (((head)->stqh_first =                                       \
 264              (head)->stqh_first->field.stqe_next) == NULL)              \
 265                 (head)->stqh_last = &(head)->stqh_first;                \
 266 } while (0)
 267
 268 #define LDAP_STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {            \
 269         if (((head)->stqh_first = (elm)->field.stqe_next) == NULL)      \
 270                 (head)->stqh_last = &(head)->stqh_first;                \
 271 } while (0)
 272
 273 #define LDAP_STAILQ_REMOVE(head, elm, type, field) do {                 \
 274         if ((head)->stqh_first == (elm)) {                              \
 275                 LDAP_STAILQ_REMOVE_HEAD(head, field);                   \
 276         }                                                               \
 277         else {                                                          \
 278                 struct type *curelm = (head)->stqh_first;               \
 279                 while( curelm->field.stqe_next != (elm) )               \
 280                         curelm = curelm->field.stqe_next;               \
 281                 if((curelm->field.stqe_next =                           \
 282                     curelm->field.stqe_next->field.stqe_next) == NULL)  \
 283                         (head)->stqh_last = &(curelm)->field.stqe_next; \
 284         }                                                               \
 285 } while (0)
 286
 287 /*
 288  * List definitions.
 289  */
 290 #define LDAP_LIST_HEAD(name, type)                                      \
 291 struct name {                                                           \
 292         struct type *lh_first;  /* first element */                     \
 293 }
 294
 295 #define LDAP_LIST_HEAD_INITIALIZER(head)                                \
 296         { NULL }
 297
 298 #define LDAP_LIST_ENTRY(type)                                           \
 299 struct {                                                                \
 300         struct type *le_next;   /* next element */                      \
 301         struct type **le_prev;  /* address of previous next element */  \
 302 }
 303
 304 #define LDAP_LIST_ENTRY_INITIALIZER(entry)                      \
 305         { NULL, NULL }
 306
 307 /*
 308  * List functions.
 309  */
 310
 311 #define LDAP_LIST_EMPTY(head) ((head)->lh_first == NULL)
 312
 313 #define LDAP_LIST_FIRST(head)   ((head)->lh_first)
 314
 315 #define LDAP_LIST_FOREACH(var, head, field)                             \
 316         for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
 317
 318 #define LDAP_LIST_INIT(head) do {                                       \
 319         (head)->lh_first = NULL;                                        \
 320 } while (0)
 321
 322 #define LDAP_LIST_ENTRY_INIT(var, field) do {                           \
 323         (var)->field.le_next = NULL;                                    \
 324         (var)->field.le_prev = NULL;                                    \
 325 } while (0)
 326
 327 #define LDAP_LIST_INSERT_AFTER(listelm, elm, field) do {                \
 328         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 329                 (listelm)->field.le_next->field.le_prev =               \
 330                     &(elm)->field.le_next;                              \
 331         (listelm)->field.le_next = (elm);                               \
 332         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 333 } while (0)
 334
 335 #define LDAP_LIST_INSERT_BEFORE(listelm, elm, field) do {               \
 336         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 337         (elm)->field.le_next = (listelm);                               \
 338         *(listelm)->field.le_prev = (elm);                              \
 339         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 340 } while (0)
 341
 342 #define LDAP_LIST_INSERT_HEAD(head, elm, field) do {                    \
 343         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 344                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 345         (head)->lh_first = (elm);                                       \
 346         (elm)->field.le_prev = &(head)->lh_first;                       \
 347 } while (0)
 348
 349 #define LDAP_LIST_NEXT(elm, field)      ((elm)->field.le_next)
 350
 351 #define LDAP_LIST_REMOVE(elm, field) do {                               \
 352         if ((elm)->field.le_next != NULL)                               \
 353                 (elm)->field.le_next->field.le_prev =                   \
 354                     (elm)->field.le_prev;                               \
 355         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 356 } while (0)
 357
 358 /*
 359  * Tail queue definitions.
 360  */
 361 #define LDAP_TAILQ_HEAD(name, type)                                     \
 362 struct name {                                                           \
 363         struct type *tqh_first; /* first element */                     \
 364         struct type **tqh_last; /* addr of last next element */         \
 365 }
 366
 367 #define LDAP_TAILQ_HEAD_INITIALIZER(head)                               \
 368         { NULL, &(head).tqh_first }
 369
 370 #define LDAP_TAILQ_ENTRY(type)                                          \
 371 struct {                                                                \
 372         struct type *tqe_next;  /* next element */                      \
 373         struct type **tqe_prev; /* address of previous next element */  \
 374 }
 375
 376 #define LDAP_TAILQ_ENTRY_INITIALIZER(entry)                             \
 377         { NULL, NULL }
 378
 379 /*
 380  * Tail queue functions.
 381  */
 382 #define LDAP_TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
 383
 384 #define LDAP_TAILQ_FOREACH(var, head, field)                            \
 385         for (var = LDAP_TAILQ_FIRST(head); var; var = LDAP_TAILQ_NEXT(var, field))
 386
 387 #define LDAP_TAILQ_FOREACH_REVERSE(var, head, type, field)              \
 388         for ((var) = LDAP_TAILQ_LAST((head), type, field);              \
 389              (var);                                                     \
 390              (var) = LDAP_TAILQ_PREV((var), head, type, field))
 391
 392 #define LDAP_TAILQ_FIRST(head) ((head)->tqh_first)
 393
 394 #define LDAP_TAILQ_LAST(head, type, field)                              \
 395         (LDAP_TAILQ_EMPTY(head) ?                                       \
 396                 NULL :                                                  \
 397                 ((struct type *)                                        \
 398                 ((char *)((head)->tqh_last) - offsetof(struct type, field))))
 399
 400 #define LDAP_TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 401
 402 #define LDAP_TAILQ_PREV(elm, head, type, field)                         \
 403         ((struct type *)((elm)->field.tqe_prev) == LDAP_TAILQ_FIRST(head) ? \
 404         NULL :                                                          \
 405         ((struct type *)                                                \
 406         ((char *)((elm)->field.tqe_prev) - offsetof(struct type, field))))
 407
 408 #define LDAP_TAILQ_INIT(head) do {                                      \
 409         (head)->tqh_first = NULL;                                       \
 410         (head)->tqh_last = &(head)->tqh_first;                          \
 411 } while (0)
 412
 413 #define LDAP_TAILQ_ENTRY_INIT(var, field) do {                          \
 414         (var)->field.tqe_next = NULL;                                   \
 415         (var)->field.tqe_prev = NULL;                                   \
 416 } while (0)
 417
 418 #define LDAP_TAILQ_INSERT_HEAD(head, elm, field) do {                   \
 419         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 420                 (head)->tqh_first->field.tqe_prev =                     \
 421                     &(elm)->field.tqe_next;                             \
 422         else                                                            \
 423                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 424         (head)->tqh_first = (elm);                                      \
 425         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 426 } while (0)
 427
 428 #define LDAP_TAILQ_INSERT_TAIL(head, elm, field) do {                   \
 429         (elm)->field.tqe_next = NULL;                                   \
 430         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 431         *(head)->tqh_last = (elm);                                      \
 432         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 433 } while (0)
 434
 435 #define LDAP_TAILQ_INSERT_AFTER(head, listelm, elm, field) do {         \
 436         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 437                 (elm)->field.tqe_next->field.tqe_prev =                 \
 438                     &(elm)->field.tqe_next;                             \
 439         else                                                            \
 440                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 441         (listelm)->field.tqe_next = (elm);                              \
 442         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 443 } while (0)
 444
 445 #define LDAP_TAILQ_INSERT_BEFORE(listelm, elm, field) do {              \
 446         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 447         (elm)->field.tqe_next = (listelm);                              \
 448         *(listelm)->field.tqe_prev = (elm);                             \
 449         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 450 } while (0)
 451
 452 #define LDAP_TAILQ_REMOVE(head, elm, field) do {                        \
 453         if (((elm)->field.tqe_next) != NULL)                            \
 454                 (elm)->field.tqe_next->field.tqe_prev =                 \
 455                     (elm)->field.tqe_prev;                              \
 456         else                                                            \
 457                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 458         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 459 } while (0)
 460
 461 /*
 462  * Circular queue definitions.
 463  */
 464 #define LDAP_CIRCLEQ_HEAD(name, type)                                   \
 465 struct name {                                                           \
 466         struct type *cqh_first;         /* first element */             \
 467         struct type *cqh_last;          /* last element */              \
 468 }
 469
 470 #define LDAP_CIRCLEQ_ENTRY(type)                                        \
 471 struct {                                                                \
 472         struct type *cqe_next;          /* next element */              \
 473         struct type *cqe_prev;          /* previous element */          \
 474 }
 475
 476 /*
 477  * Circular queue functions.
 478  */
 479 #define LDAP_CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 480
 481 #define LDAP_CIRCLEQ_FIRST(head) ((head)->cqh_first)
 482
 483 #define LDAP_CIRCLEQ_FOREACH(var, head, field)                          \
 484         for((var) = (head)->cqh_first;                                  \
 485             (var) != (void *)(head);                                    \
 486             (var) = (var)->field.cqe_next)
 487
 488 #define LDAP_CIRCLEQ_FOREACH_REVERSE(var, head, field)                  \
 489         for((var) = (head)->cqh_last;                                   \
 490             (var) != (void *)(head);                                    \
 491             (var) = (var)->field.cqe_prev)
 492
 493 #define LDAP_CIRCLEQ_INIT(head) do {                                    \
 494         (head)->cqh_first = (void *)(head);                             \
 495         (head)->cqh_last = (void *)(head);                              \
 496 } while (0)
 497
 498 #define LDAP_CIRCLEQ_ENTRY_INIT(var, field) do {                        \
 499         (var)->field.cqe_next = NULL;                                   \
 500         (var)->field.cqe_prev = NULL;                                   \
 501 } while (0)
 502
 503 #define LDAP_CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {       \
 504         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 505         (elm)->field.cqe_prev = (listelm);                              \
 506         if ((listelm)->field.cqe_next == (void *)(head))                \
 507                 (head)->cqh_last = (elm);                               \
 508         else                                                            \
 509                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 510         (listelm)->field.cqe_next = (elm);                              \
 511 } while (0)
 512
 513 #define LDAP_CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {      \
 514         (elm)->field.cqe_next = (listelm);                              \
 515         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 516         if ((listelm)->field.cqe_prev == (void *)(head))                \
 517                 (head)->cqh_first = (elm);                              \
 518         else                                                            \
 519                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 520         (listelm)->field.cqe_prev = (elm);                              \
 521 } while (0)
 522
 523 #define LDAP_CIRCLEQ_INSERT_HEAD(head, elm, field) do {                 \
 524         (elm)->field.cqe_next = (head)->cqh_first;                      \
 525         (elm)->field.cqe_prev = (void *)(head);                         \
 526         if ((head)->cqh_last == (void *)(head))                         \
 527                 (head)->cqh_last = (elm);                               \
 528         else                                                            \
 529                 (head)->cqh_first->field.cqe_prev = (elm);              \
 530         (head)->cqh_first = (elm);                                      \
 531 } while (0)
 532
 533 #define LDAP_CIRCLEQ_INSERT_TAIL(head, elm, field) do {                 \
 534         (elm)->field.cqe_next = (void *)(head);                         \
 535         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 536         if ((head)->cqh_first == (void *)(head))                        \
 537                 (head)->cqh_first = (elm);                              \
 538         else                                                            \
 539                 (head)->cqh_last->field.cqe_next = (elm);               \
 540         (head)->cqh_last = (elm);                                       \
 541 } while (0)
 542
 543 #define LDAP_CIRCLEQ_LAST(head) ((head)->cqh_last)
 544
 545 #define LDAP_CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
 546
 547 #define LDAP_CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
 548
 549 #define LDAP_CIRCLEQ_REMOVE(head, elm, field) do {                      \
 550         if ((elm)->field.cqe_next == (void *)(head))                    \
 551                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 552         else                                                            \
 553                 (elm)->field.cqe_next->field.cqe_prev =                 \
 554                     (elm)->field.cqe_prev;                              \
 555         if ((elm)->field.cqe_prev == (void *)(head))                    \
 556                 (head)->cqh_first = (elm)->field.cqe_next;              \
 557         else                                                            \
 558                 (elm)->field.cqe_prev->field.cqe_next =                 \
 559                     (elm)->field.cqe_next;                              \
 560 } while (0)
 561
 562 #endif /* !_LDAP_QUEUE_H_ */