1 /* ldap_queue.h -- queue macros */ 2 /* $OpenLDAP$ */ 3 /* This work is part of OpenLDAP Software <http://www.openldap.org/>. 4 * 5 * Copyright 2001-2021 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_ */ 594