git.sur5r.net Git - openldap/blob - include/queue-compat.h

   1 /*
   2  * Copyright 2001 The OpenLDAP Foundation, Redwood City, California, USA
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted only as authorized by the OpenLDAP
   7  * Public License.  A copy of this license is available at
   8  * http://www.OpenLDAP.org/license.html or in file LICENSE in the
   9  * top-level directory of the distribution.
  10  */
  11 /* stolen from FreeBSD for use in OpenLDAP */
  12 /*
  13  * Copyright (c) 1991, 1993
  14  *      The Regents of the University of California.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  * 3. All advertising materials mentioning features or use of this software
  25  *    must display the following acknowledgement:
  26  *      This product includes software developed by the University of
  27  *      California, Berkeley and its contributors.
  28  * 4. Neither the name of the University nor the names of its contributors
  29  *    may be used to endorse or promote products derived from this software
  30  *    without specific prior written permission.
  31  *
  32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  42  * SUCH DAMAGE.
  43  *
  44  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  45  * $FreeBSD: src/sys/sys/queue.h,v 1.32.2.5 2001/09/30 21:12:54 luigi Exp $
  46  */
  47
  48 #ifndef _SYS_QUEUE_H_
  49 #define _SYS_QUEUE_H_
  50
  51 #define __offsetof      offsetof
  52
  53 /*
  54  * This file defines five types of data structures: singly-linked lists,
  55  * singly-linked tail queues, lists, tail queues, and circular queues.
  56  *
  57  * A singly-linked list is headed by a single forward pointer. The elements
  58  * are singly linked for minimum space and pointer manipulation overhead at
  59  * the expense of O(n) removal for arbitrary elements. New elements can be
  60  * added to the list after an existing element or at the head of the list.
  61  * Elements being removed from the head of the list should use the explicit
  62  * macro for this purpose for optimum efficiency. A singly-linked list may
  63  * only be traversed in the forward direction.  Singly-linked lists are ideal
  64  * for applications with large datasets and few or no removals or for
  65  * implementing a LIFO queue.
  66  *
  67  * A singly-linked tail queue is headed by a pair of pointers, one to the
  68  * head of the list and the other to the tail of the list. The elements are
  69  * singly linked for minimum space and pointer manipulation overhead at the
  70  * expense of O(n) removal for arbitrary elements. New elements can be added
  71  * to the list after an existing element, at the head of the list, or at the
  72  * end of the list. Elements being removed from the head of the tail queue
  73  * should use the explicit macro for this purpose for optimum efficiency.
  74  * A singly-linked tail queue may only be traversed in the forward direction.
  75  * Singly-linked tail queues are ideal for applications with large datasets
  76  * and few or no removals or for implementing a FIFO queue.
  77  *
  78  * A list is headed by a single forward pointer (or an array of forward
  79  * pointers for a hash table header). The elements are doubly linked
  80  * so that an arbitrary element can be removed without a need to
  81  * traverse the list. New elements can be added to the list before
  82  * or after an existing element or at the head of the list. A list
  83  * may only be traversed in the forward direction.
  84  *
  85  * A tail queue is headed by a pair of pointers, one to the head of the
  86  * list and the other to the tail of the list. The elements are doubly
  87  * linked 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 or
  89  * after an existing element, at the head of the list, or at the end of
  90  * the list. A tail queue may be traversed in either direction.
  91  *
  92  * A circle 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 after
  96  * an existing element, at the head of the list, or at the end of the list.
  97  * A circle queue may be traversed in either direction, but has a more
  98  * complex end of list detection.
  99  *
 100  * For details on the use of these macros, see the queue(3) manual page.
 101  *
 102  *
 103  *                      SLIST   LIST    STAILQ  TAILQ   CIRCLEQ
 104  * _HEAD                +       +       +       +       +
 105  * _ENTRY               +       +       +       +       +
 106  * _INIT                +       +       +       +       +
 107  * _EMPTY               +       +       +       +       +
 108  * _FIRST               +       +       +       +       +
 109  * _NEXT                +       +       +       +       +
 110  * _PREV                -       -       -       +       +
 111  * _LAST                -       -       +       +       +
 112  * _FOREACH             +       +       +       +       +
 113  * _FOREACH_REVERSE     -       -       -       +       +
 114  * _INSERT_HEAD         +       +       +       +       +
 115  * _INSERT_BEFORE       -       +       -       +       +
 116  * _INSERT_AFTER        +       +       +       +       +
 117  * _INSERT_TAIL         -       -       +       +       +
 118  * _REMOVE_HEAD         +       -       +       -       -
 119  * _REMOVE              +       +       +       +       +
 120  *
 121  */
 122
 123 /*
 124  * Singly-linked List definitions.
 125  */
 126 #define SLIST_HEAD(name, type)                                          \
 127 struct name {                                                           \
 128         struct type *slh_first; /* first element */                     \
 129 }
 130
 131 #define SLIST_HEAD_INITIALIZER(head)                                    \
 132         { NULL }
 133
 134 #define SLIST_ENTRY(type)                                               \
 135 struct {                                                                \
 136         struct type *sle_next;  /* next element */                      \
 137 }
 138
 139 /*
 140  * Singly-linked List functions.
 141  */
 142 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 143
 144 #define SLIST_FIRST(head)       ((head)->slh_first)
 145
 146 #define SLIST_FOREACH(var, head, field)                                 \
 147         for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
 148
 149 #define SLIST_INIT(head) {                                              \
 150         (head)->slh_first = NULL;                                       \
 151 }
 152
 153 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 154         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 155         (slistelm)->field.sle_next = (elm);                             \
 156 } while (0)
 157
 158 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 159         (elm)->field.sle_next = (head)->slh_first;                      \
 160         (head)->slh_first = (elm);                                      \
 161 } while (0)
 162
 163 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 164
 165 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 166         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 167 } while (0)
 168
 169 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 170         if ((head)->slh_first == (elm)) {                               \
 171                 SLIST_REMOVE_HEAD((head), field);                       \
 172         }                                                               \
 173         else {                                                          \
 174                 struct type *curelm = (head)->slh_first;                \
 175                 while( curelm->field.sle_next != (elm) )                \
 176                         curelm = curelm->field.sle_next;                \
 177                 curelm->field.sle_next =                                \
 178                     curelm->field.sle_next->field.sle_next;             \
 179         }                                                               \
 180 } while (0)
 181
 182 /*
 183  * Singly-linked Tail queue definitions.
 184  */
 185 #define STAILQ_HEAD(name, type)                                         \
 186 struct name {                                                           \
 187         struct type *stqh_first;/* first element */                     \
 188         struct type **stqh_last;/* addr of last next element */         \
 189 }
 190
 191 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 192         { NULL, &(head).stqh_first }
 193
 194 #define STAILQ_ENTRY(type)                                              \
 195 struct {                                                                \
 196         struct type *stqe_next; /* next element */                      \
 197 }
 198
 199 /*
 200  * Singly-linked Tail queue functions.
 201  */
 202 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
 203
 204 #define STAILQ_INIT(head) do {                                          \
 205         (head)->stqh_first = NULL;                                      \
 206         (head)->stqh_last = &(head)->stqh_first;                        \
 207 } while (0)
 208
 209 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 210
 211 #define STAILQ_LAST(head, type, field)                                  \
 212         (STAILQ_EMPTY(head) ?                                           \
 213                 NULL :                                                  \
 214                 ((struct type *)                                        \
 215                 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
 216
 217 #define STAILQ_FOREACH(var, head, field)                                \
 218         for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next)
 219
 220 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 221         if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
 222                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 223         (head)->stqh_first = (elm);                                     \
 224 } while (0)
 225
 226 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 227         (elm)->field.stqe_next = NULL;                                  \
 228         *(head)->stqh_last = (elm);                                     \
 229         (head)->stqh_last = &(elm)->field.stqe_next;                    \
 230 } while (0)
 231
 232 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {               \
 233         if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
 234                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 235         (tqelm)->field.stqe_next = (elm);                               \
 236 } while (0)
 237
 238 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 239
 240 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 241         if (((head)->stqh_first =                                       \
 242              (head)->stqh_first->field.stqe_next) == NULL)              \
 243                 (head)->stqh_last = &(head)->stqh_first;                \
 244 } while (0)
 245
 246 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {                 \
 247         if (((head)->stqh_first = (elm)->field.stqe_next) == NULL)      \
 248                 (head)->stqh_last = &(head)->stqh_first;                \
 249 } while (0)
 250
 251 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 252         if ((head)->stqh_first == (elm)) {                              \
 253                 STAILQ_REMOVE_HEAD(head, field);                        \
 254         }                                                               \
 255         else {                                                          \
 256                 struct type *curelm = (head)->stqh_first;               \
 257                 while( curelm->field.stqe_next != (elm) )               \
 258                         curelm = curelm->field.stqe_next;               \
 259                 if((curelm->field.stqe_next =                           \
 260                     curelm->field.stqe_next->field.stqe_next) == NULL)  \
 261                         (head)->stqh_last = &(curelm)->field.stqe_next; \
 262         }                                                               \
 263 } while (0)
 264
 265 /*
 266  * List definitions.
 267  */
 268 #define LIST_HEAD(name, type)                                           \
 269 struct name {                                                           \
 270         struct type *lh_first;  /* first element */                     \
 271 }
 272
 273 #define LIST_HEAD_INITIALIZER(head)                                     \
 274         { NULL }
 275
 276 #define LIST_ENTRY(type)                                                \
 277 struct {                                                                \
 278         struct type *le_next;   /* next element */                      \
 279         struct type **le_prev;  /* address of previous next element */  \
 280 }
 281
 282 /*
 283  * List functions.
 284  */
 285
 286 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
 287
 288 #define LIST_FIRST(head)        ((head)->lh_first)
 289
 290 #define LIST_FOREACH(var, head, field)                                  \
 291         for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
 292
 293 #define LIST_INIT(head) do {                                            \
 294         (head)->lh_first = NULL;                                        \
 295 } while (0)
 296
 297 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 298         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 299                 (listelm)->field.le_next->field.le_prev =               \
 300                     &(elm)->field.le_next;                              \
 301         (listelm)->field.le_next = (elm);                               \
 302         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 303 } while (0)
 304
 305 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 306         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 307         (elm)->field.le_next = (listelm);                               \
 308         *(listelm)->field.le_prev = (elm);                              \
 309         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 310 } while (0)
 311
 312 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 313         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 314                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 315         (head)->lh_first = (elm);                                       \
 316         (elm)->field.le_prev = &(head)->lh_first;                       \
 317 } while (0)
 318
 319 #define LIST_NEXT(elm, field)   ((elm)->field.le_next)
 320
 321 #define LIST_REMOVE(elm, field) do {                                    \
 322         if ((elm)->field.le_next != NULL)                               \
 323                 (elm)->field.le_next->field.le_prev =                   \
 324                     (elm)->field.le_prev;                               \
 325         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 326 } while (0)
 327
 328 /*
 329  * Tail queue definitions.
 330  */
 331 #define TAILQ_HEAD(name, type)                                          \
 332 struct name {                                                           \
 333         struct type *tqh_first; /* first element */                     \
 334         struct type **tqh_last; /* addr of last next element */         \
 335 }
 336
 337 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 338         { NULL, &(head).tqh_first }
 339
 340 #define TAILQ_ENTRY(type)                                               \
 341 struct {                                                                \
 342         struct type *tqe_next;  /* next element */                      \
 343         struct type **tqe_prev; /* address of previous next element */  \
 344 }
 345
 346 /*
 347  * Tail queue functions.
 348  */
 349 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
 350
 351 #define TAILQ_FOREACH(var, head, field)                                 \
 352         for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field))
 353
 354 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 355         for ((var) = TAILQ_LAST((head), headname);                      \
 356              (var);                                                     \
 357              (var) = TAILQ_PREV((var), headname, field))
 358
 359 #define TAILQ_FIRST(head) ((head)->tqh_first)
 360
 361 #define TAILQ_LAST(head, headname) \
 362         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 363
 364 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 365
 366 #define TAILQ_PREV(elm, headname, field) \
 367         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 368
 369 #define TAILQ_INIT(head) do {                                           \
 370         (head)->tqh_first = NULL;                                       \
 371         (head)->tqh_last = &(head)->tqh_first;                          \
 372 } while (0)
 373
 374 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 375         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 376                 (head)->tqh_first->field.tqe_prev =                     \
 377                     &(elm)->field.tqe_next;                             \
 378         else                                                            \
 379                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 380         (head)->tqh_first = (elm);                                      \
 381         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 382 } while (0)
 383
 384 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 385         (elm)->field.tqe_next = NULL;                                   \
 386         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 387         *(head)->tqh_last = (elm);                                      \
 388         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 389 } while (0)
 390
 391 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 392         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 393                 (elm)->field.tqe_next->field.tqe_prev =                 \
 394                     &(elm)->field.tqe_next;                             \
 395         else                                                            \
 396                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 397         (listelm)->field.tqe_next = (elm);                              \
 398         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 399 } while (0)
 400
 401 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 402         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 403         (elm)->field.tqe_next = (listelm);                              \
 404         *(listelm)->field.tqe_prev = (elm);                             \
 405         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 406 } while (0)
 407
 408 #define TAILQ_REMOVE(head, elm, field) do {                             \
 409         if (((elm)->field.tqe_next) != NULL)                            \
 410                 (elm)->field.tqe_next->field.tqe_prev =                 \
 411                     (elm)->field.tqe_prev;                              \
 412         else                                                            \
 413                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 414         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 415 } while (0)
 416
 417 /*
 418  * Circular queue definitions.
 419  */
 420 #define CIRCLEQ_HEAD(name, type)                                        \
 421 struct name {                                                           \
 422         struct type *cqh_first;         /* first element */             \
 423         struct type *cqh_last;          /* last element */              \
 424 }
 425
 426 #define CIRCLEQ_ENTRY(type)                                             \
 427 struct {                                                                \
 428         struct type *cqe_next;          /* next element */              \
 429         struct type *cqe_prev;          /* previous element */          \
 430 }
 431
 432 /*
 433  * Circular queue functions.
 434  */
 435 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 436
 437 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
 438
 439 #define CIRCLEQ_FOREACH(var, head, field)                               \
 440         for((var) = (head)->cqh_first;                                  \
 441             (var) != (void *)(head);                                    \
 442             (var) = (var)->field.cqe_next)
 443
 444 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 445         for((var) = (head)->cqh_last;                                   \
 446             (var) != (void *)(head);                                    \
 447             (var) = (var)->field.cqe_prev)
 448
 449 #define CIRCLEQ_INIT(head) do {                                         \
 450         (head)->cqh_first = (void *)(head);                             \
 451         (head)->cqh_last = (void *)(head);                              \
 452 } while (0)
 453
 454 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 455         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 456         (elm)->field.cqe_prev = (listelm);                              \
 457         if ((listelm)->field.cqe_next == (void *)(head))                \
 458                 (head)->cqh_last = (elm);                               \
 459         else                                                            \
 460                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 461         (listelm)->field.cqe_next = (elm);                              \
 462 } while (0)
 463
 464 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 465         (elm)->field.cqe_next = (listelm);                              \
 466         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 467         if ((listelm)->field.cqe_prev == (void *)(head))                \
 468                 (head)->cqh_first = (elm);                              \
 469         else                                                            \
 470                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 471         (listelm)->field.cqe_prev = (elm);                              \
 472 } while (0)
 473
 474 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 475         (elm)->field.cqe_next = (head)->cqh_first;                      \
 476         (elm)->field.cqe_prev = (void *)(head);                         \
 477         if ((head)->cqh_last == (void *)(head))                         \
 478                 (head)->cqh_last = (elm);                               \
 479         else                                                            \
 480                 (head)->cqh_first->field.cqe_prev = (elm);              \
 481         (head)->cqh_first = (elm);                                      \
 482 } while (0)
 483
 484 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 485         (elm)->field.cqe_next = (void *)(head);                         \
 486         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 487         if ((head)->cqh_first == (void *)(head))                        \
 488                 (head)->cqh_first = (elm);                              \
 489         else                                                            \
 490                 (head)->cqh_last->field.cqe_next = (elm);               \
 491         (head)->cqh_last = (elm);                                       \
 492 } while (0)
 493
 494 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
 495
 496 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
 497
 498 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
 499
 500 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 501         if ((elm)->field.cqe_next == (void *)(head))                    \
 502                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 503         else                                                            \
 504                 (elm)->field.cqe_next->field.cqe_prev =                 \
 505                     (elm)->field.cqe_prev;                              \
 506         if ((elm)->field.cqe_prev == (void *)(head))                    \
 507                 (head)->cqh_first = (elm)->field.cqe_next;              \
 508         else                                                            \
 509                 (elm)->field.cqe_prev->field.cqe_next =                 \
 510                     (elm)->field.cqe_next;                              \
 511 } while (0)
 512
 513 #endif /* !_SYS_QUEUE_H_ */