utils/idmapd/queue.h

   1 /*      $OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos Exp $      */
   2 /*      $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $       */
   3
   4 /*
   5  * Copyright (c) 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  33  */
  34
  35 #ifndef _SYS_QUEUE_H_
  36 #define _SYS_QUEUE_H_
  37
  38 /*
  39  * This file defines five types of data structures: singly-linked lists,
  40  * lists, simple queues, tail queues, and circular queues.
  41  *
  42  *
  43  * A singly-linked list is headed by a single forward pointer. The elements
  44  * are singly linked for minimum space and pointer manipulation overhead at
  45  * the expense of O(n) removal for arbitrary elements. New elements can be
  46  * added to the list after an existing element or at the head of the list.
  47  * Elements being removed from the head of the list should use the explicit
  48  * macro for this purpose for optimum efficiency. A singly-linked list may
  49  * only be traversed in the forward direction.  Singly-linked lists are ideal
  50  * for applications with large datasets and few or no removals or for
  51  * implementing a LIFO queue.
  52  *
  53  * A list is headed by a single forward pointer (or an array of forward
  54  * pointers for a hash table header). The elements are doubly linked
  55  * so that an arbitrary element can be removed without a need to
  56  * traverse the list. New elements can be added to the list before
  57  * or after an existing element or at the head of the list. A list
  58  * may only be traversed in the forward direction.
  59  *
  60  * A simple queue is headed by a pair of pointers, one the head of the
  61  * list and the other to the tail of the list. The elements are singly
  62  * linked to save space, so elements can only be removed from the
  63  * head of the list. New elements can be added to the list before or after
  64  * an existing element, at the head of the list, or at the end of the
  65  * list. A simple queue may only be traversed in the forward direction.
  66  *
  67  * A tail queue is headed by a pair of pointers, one to the head of the
  68  * list and the other to the tail of the list. The elements are doubly
  69  * linked so that an arbitrary element can be removed without a need to
  70  * traverse the list. New elements can be added to the list before or
  71  * after an existing element, at the head of the list, or at the end of
  72  * the list. A tail queue may be traversed in either direction.
  73  *
  74  * A circle queue is headed by a pair of pointers, one to the head of the
  75  * list and the other to the tail of the list. The elements are doubly
  76  * linked so that an arbitrary element can be removed without a need to
  77  * traverse the list. New elements can be added to the list before or after
  78  * an existing element, at the head of the list, or at the end of the list.
  79  * A circle queue may be traversed in either direction, but has a more
  80  * complex end of list detection.
  81  *
  82  * For details on the use of these macros, see the queue(3) manual page.
  83  */
  84
  85 /*
  86  * Singly-linked List definitions.
  87  */
  88 #define SLIST_HEAD(name, type)                                          \
  89 struct name {                                                           \
  90         struct type *slh_first; /* first element */                     \
  91 }
  92
  93 #define SLIST_HEAD_INITIALIZER(head)                                    \
  94         { NULL }
  95
  96 #define SLIST_ENTRY(type)                                               \
  97 struct {                                                                \
  98         struct type *sle_next;  /* next element */                      \
  99 }
 100
 101 /*
 102  * Singly-linked List access methods.
 103  */
 104 #define SLIST_FIRST(head)       ((head)->slh_first)
 105 #define SLIST_END(head)         NULL
 106 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 107 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 108
 109 #define SLIST_FOREACH(var, head, field)                                 \
 110         for((var) = SLIST_FIRST(head);                                  \
 111             (var) != SLIST_END(head);                                   \
 112             (var) = SLIST_NEXT(var, field))
 113
 114 /*
 115  * Singly-linked List functions.
 116  */
 117 #define SLIST_INIT(head) {                                              \
 118         SLIST_FIRST(head) = SLIST_END(head);                            \
 119 }
 120
 121 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 122         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 123         (slistelm)->field.sle_next = (elm);                             \
 124 } while (0)
 125
 126 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 127         (elm)->field.sle_next = (head)->slh_first;                      \
 128         (head)->slh_first = (elm);                                      \
 129 } while (0)
 130
 131 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 132         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 133 } while (0)
 134
 135 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 136         if ((head)->slh_first == (elm)) {                               \
 137                 SLIST_REMOVE_HEAD((head), field);                       \
 138         }                                                               \
 139         else {                                                          \
 140                 struct type *curelm = (head)->slh_first;                \
 141                 while( curelm->field.sle_next != (elm) )                \
 142                         curelm = curelm->field.sle_next;                \
 143                 curelm->field.sle_next =                                \
 144                     curelm->field.sle_next->field.sle_next;             \
 145         }                                                               \
 146 } while (0)
 147
 148 /*
 149  * List definitions.
 150  */
 151 #define LIST_HEAD(name, type)                                           \
 152 struct name {                                                           \
 153         struct type *lh_first;  /* first element */                     \
 154 }
 155
 156 #define LIST_HEAD_INITIALIZER(head)                                     \
 157         { NULL }
 158
 159 #define LIST_ENTRY(type)                                                \
 160 struct {                                                                \
 161         struct type *le_next;   /* next element */                      \
 162         struct type **le_prev;  /* address of previous next element */  \
 163 }
 164
 165 /*
 166  * List access methods
 167  */
 168 #define LIST_FIRST(head)                ((head)->lh_first)
 169 #define LIST_END(head)                  NULL
 170 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 171 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 172
 173 #define LIST_FOREACH(var, head, field)                                  \
 174         for((var) = LIST_FIRST(head);                                   \
 175             (var)!= LIST_END(head);                                     \
 176             (var) = LIST_NEXT(var, field))
 177
 178 /*
 179  * List functions.
 180  */
 181 #define LIST_INIT(head) do {                                            \
 182         LIST_FIRST(head) = LIST_END(head);                              \
 183 } while (0)
 184
 185 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 186         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 187                 (listelm)->field.le_next->field.le_prev =               \
 188                     &(elm)->field.le_next;                              \
 189         (listelm)->field.le_next = (elm);                               \
 190         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 191 } while (0)
 192
 193 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 194         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 195         (elm)->field.le_next = (listelm);                               \
 196         *(listelm)->field.le_prev = (elm);                              \
 197         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 198 } while (0)
 199
 200 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 201         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 202                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 203         (head)->lh_first = (elm);                                       \
 204         (elm)->field.le_prev = &(head)->lh_first;                       \
 205 } while (0)
 206
 207 #define LIST_REMOVE(elm, field) do {                                    \
 208         if ((elm)->field.le_next != NULL)                               \
 209                 (elm)->field.le_next->field.le_prev =                   \
 210                     (elm)->field.le_prev;                               \
 211         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 212 } while (0)
 213
 214 #define LIST_REPLACE(elm, elm2, field) do {                             \
 215         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 216                 (elm2)->field.le_next->field.le_prev =                  \
 217                     &(elm2)->field.le_next;                             \
 218         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 219         *(elm2)->field.le_prev = (elm2);                                \
 220 } while (0)
 221
 222 /*
 223  * Simple queue definitions.
 224  */
 225 #define SIMPLEQ_HEAD(name, type)                                        \
 226 struct name {                                                           \
 227         struct type *sqh_first; /* first element */                     \
 228         struct type **sqh_last; /* addr of last next element */         \
 229 }
 230
 231 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 232         { NULL, &(head).sqh_first }
 233
 234 #define SIMPLEQ_ENTRY(type)                                             \
 235 struct {                                                                \
 236         struct type *sqe_next;  /* next element */                      \
 237 }
 238
 239 /*
 240  * Simple queue access methods.
 241  */
 242 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 243 #define SIMPLEQ_END(head)           NULL
 244 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 245 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 246
 247 #define SIMPLEQ_FOREACH(var, head, field)                               \
 248         for((var) = SIMPLEQ_FIRST(head);                                \
 249             (var) != SIMPLEQ_END(head);                                 \
 250             (var) = SIMPLEQ_NEXT(var, field))
 251
 252 /*
 253  * Simple queue functions.
 254  */
 255 #define SIMPLEQ_INIT(head) do {                                         \
 256         (head)->sqh_first = NULL;                                       \
 257         (head)->sqh_last = &(head)->sqh_first;                          \
 258 } while (0)
 259
 260 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 261         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 262                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 263         (head)->sqh_first = (elm);                                      \
 264 } while (0)
 265
 266 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 267         (elm)->field.sqe_next = NULL;                                   \
 268         *(head)->sqh_last = (elm);                                      \
 269         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 270 } while (0)
 271
 272 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 273         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 274                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 275         (listelm)->field.sqe_next = (elm);                              \
 276 } while (0)
 277
 278 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {                      \
 279         if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)        \
 280                 (head)->sqh_last = &(head)->sqh_first;                  \
 281 } while (0)
 282
 283 /*
 284  * Tail queue definitions.
 285  */
 286 #define TAILQ_HEAD(name, type)                                          \
 287 struct name {                                                           \
 288         struct type *tqh_first; /* first element */                     \
 289         struct type **tqh_last; /* addr of last next element */         \
 290 }
 291
 292 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 293         { NULL, &(head).tqh_first }
 294
 295 #define TAILQ_ENTRY(type)                                               \
 296 struct {                                                                \
 297         struct type *tqe_next;  /* next element */                      \
 298         struct type **tqe_prev; /* address of previous next element */  \
 299 }
 300
 301 /*
 302  * tail queue access methods
 303  */
 304 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 305 #define TAILQ_END(head)                 NULL
 306 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 307 #define TAILQ_LAST(head, headname)                                      \
 308         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 309 /* XXX */
 310 #define TAILQ_PREV(elm, headname, field)                                \
 311         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 312 #define TAILQ_EMPTY(head)                                               \
 313         (TAILQ_FIRST(head) == TAILQ_END(head))
 314
 315 #define TAILQ_FOREACH(var, head, field)                                 \
 316         for((var) = TAILQ_FIRST(head);                                  \
 317             (var) != TAILQ_END(head);                                   \
 318             (var) = TAILQ_NEXT(var, field))
 319
 320 #define TAILQ_FOREACH_REVERSE(var, head, field, headname)               \
 321         for((var) = TAILQ_LAST(head, headname);                         \
 322             (var) != TAILQ_END(head);                                   \
 323             (var) = TAILQ_PREV(var, headname, field))
 324
 325 /*
 326  * Tail queue functions.
 327  */
 328 #define TAILQ_INIT(head) do {                                           \
 329         (head)->tqh_first = NULL;                                       \
 330         (head)->tqh_last = &(head)->tqh_first;                          \
 331 } while (0)
 332
 333 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 334         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 335                 (head)->tqh_first->field.tqe_prev =                     \
 336                     &(elm)->field.tqe_next;                             \
 337         else                                                            \
 338                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 339         (head)->tqh_first = (elm);                                      \
 340         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 341 } while (0)
 342
 343 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 344         (elm)->field.tqe_next = NULL;                                   \
 345         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 346         *(head)->tqh_last = (elm);                                      \
 347         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 348 } while (0)
 349
 350 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 351         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 352                 (elm)->field.tqe_next->field.tqe_prev =                 \
 353                     &(elm)->field.tqe_next;                             \
 354         else                                                            \
 355                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 356         (listelm)->field.tqe_next = (elm);                              \
 357         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 358 } while (0)
 359
 360 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 361         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 362         (elm)->field.tqe_next = (listelm);                              \
 363         *(listelm)->field.tqe_prev = (elm);                             \
 364         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 365 } while (0)
 366
 367 #define TAILQ_REMOVE(head, elm, field) do {                             \
 368         if (((elm)->field.tqe_next) != NULL)                            \
 369                 (elm)->field.tqe_next->field.tqe_prev =                 \
 370                     (elm)->field.tqe_prev;                              \
 371         else                                                            \
 372                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 373         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 374 } while (0)
 375
 376 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 377         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 378                 (elm2)->field.tqe_next->field.tqe_prev =                \
 379                     &(elm2)->field.tqe_next;                            \
 380         else                                                            \
 381                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 382         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 383         *(elm2)->field.tqe_prev = (elm2);                               \
 384 } while (0)
 385
 386 /*
 387  * Circular queue definitions.
 388  */
 389 #define CIRCLEQ_HEAD(name, type)                                        \
 390 struct name {                                                           \
 391         struct type *cqh_first;         /* first element */             \
 392         struct type *cqh_last;          /* last element */              \
 393 }
 394
 395 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 396         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 397
 398 #define CIRCLEQ_ENTRY(type)                                             \
 399 struct {                                                                \
 400         struct type *cqe_next;          /* next element */              \
 401         struct type *cqe_prev;          /* previous element */          \
 402 }
 403
 404 /*
 405  * Circular queue access methods
 406  */
 407 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 408 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 409 #define CIRCLEQ_END(head)               ((void *)(head))
 410 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 411 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 412 #define CIRCLEQ_EMPTY(head)                                             \
 413         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 414
 415 #define CIRCLEQ_FOREACH(var, head, field)                               \
 416         for((var) = CIRCLEQ_FIRST(head);                                \
 417             (var) != CIRCLEQ_END(head);                                 \
 418             (var) = CIRCLEQ_NEXT(var, field))
 419
 420 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 421         for((var) = CIRCLEQ_LAST(head);                                 \
 422             (var) != CIRCLEQ_END(head);                                 \
 423             (var) = CIRCLEQ_PREV(var, field))
 424
 425 /*
 426  * Circular queue functions.
 427  */
 428 #define CIRCLEQ_INIT(head) do {                                         \
 429         (head)->cqh_first = CIRCLEQ_END(head);                          \
 430         (head)->cqh_last = CIRCLEQ_END(head);                           \
 431 } while (0)
 432
 433 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 434         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 435         (elm)->field.cqe_prev = (listelm);                              \
 436         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 437                 (head)->cqh_last = (elm);                               \
 438         else                                                            \
 439                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 440         (listelm)->field.cqe_next = (elm);                              \
 441 } while (0)
 442
 443 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 444         (elm)->field.cqe_next = (listelm);                              \
 445         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 446         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 447                 (head)->cqh_first = (elm);                              \
 448         else                                                            \
 449                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 450         (listelm)->field.cqe_prev = (elm);                              \
 451 } while (0)
 452
 453 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 454         (elm)->field.cqe_next = (head)->cqh_first;                      \
 455         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 456         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 457                 (head)->cqh_last = (elm);                               \
 458         else                                                            \
 459                 (head)->cqh_first->field.cqe_prev = (elm);              \
 460         (head)->cqh_first = (elm);                                      \
 461 } while (0)
 462
 463 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 464         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 465         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 466         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 467                 (head)->cqh_first = (elm);                              \
 468         else                                                            \
 469                 (head)->cqh_last->field.cqe_next = (elm);               \
 470         (head)->cqh_last = (elm);                                       \
 471 } while (0)
 472
 473 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 474         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 475                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 476         else                                                            \
 477                 (elm)->field.cqe_next->field.cqe_prev =                 \
 478                     (elm)->field.cqe_prev;                              \
 479         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 480                 (head)->cqh_first = (elm)->field.cqe_next;              \
 481         else                                                            \
 482                 (elm)->field.cqe_prev->field.cqe_next =                 \
 483                     (elm)->field.cqe_next;                              \
 484 } while (0)
 485
 486 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 487         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 488             CIRCLEQ_END(head))                                          \
 489                 (head).cqh_last = (elm2);                               \
 490         else                                                            \
 491                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 492         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 493             CIRCLEQ_END(head))                                          \
 494                 (head).cqh_first = (elm2);                              \
 495         else                                                            \
 496                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 497 } while (0)
 498
 499 #endif  /* !_SYS_QUEUE_H_ */