openssh/openbsd-compat/fake-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. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  37  */
  38
  39 #ifndef _SYS_QUEUE_H_
  40 #define _SYS_QUEUE_H_
  41
  42 /*
  43  * This file defines five types of data structures: singly-linked lists,
  44  * lists, simple queues, tail queues, and circular queues.
  45  *
  46  *
  47  * A singly-linked list is headed by a single forward pointer. The elements
  48  * are singly linked for minimum space and pointer manipulation overhead at
  49  * the expense of O(n) removal for arbitrary elements. New elements can be
  50  * added to the list after an existing element or at the head of the list.
  51  * Elements being removed from the head of the list should use the explicit
  52  * macro for this purpose for optimum efficiency. A singly-linked list may
  53  * only be traversed in the forward direction.  Singly-linked lists are ideal
  54  * for applications with large datasets and few or no removals or for
  55  * implementing a LIFO queue.
  56  *
  57  * A list is headed by a single forward pointer (or an array of forward
  58  * pointers for a hash table header). The elements are doubly linked
  59  * so that an arbitrary element can be removed without a need to
  60  * traverse the list. New elements can be added to the list before
  61  * or after an existing element or at the head of the list. A list
  62  * may only be traversed in the forward direction.
  63  *
  64  * A simple queue is headed by a pair of pointers, one the head of the
  65  * list and the other to the tail of the list. The elements are singly
  66  * linked to save space, so elements can only be removed from the
  67  * head of the list. New elements can be added to the list before or after
  68  * an existing element, at the head of the list, or at the end of the
  69  * list. A simple queue may only be traversed in the forward direction.
  70  *
  71  * A tail queue is headed by a pair of pointers, one to the head of the
  72  * list and the other to the tail of the list. The elements are doubly
  73  * linked so that an arbitrary element can be removed without a need to
  74  * traverse the list. New elements can be added to the list before or
  75  * after an existing element, at the head of the list, or at the end of
  76  * the list. A tail queue may be traversed in either direction.
  77  *
  78  * A circle queue is headed by a pair of pointers, one to the head of the
  79  * list and the other to the tail of the list. The elements are doubly
  80  * linked 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 or after
  82  * an existing element, at the head of the list, or at the end of the list.
  83  * A circle queue may be traversed in either direction, but has a more
  84  * complex end of list detection.
  85  *
  86  * For details on the use of these macros, see the queue(3) manual page.
  87  */
  88
  89 /*
  90  * Singly-linked List definitions.
  91  */
  92 #define SLIST_HEAD(name, type)                                          \
  93 struct name {                                                           \
  94         struct type *slh_first; /* first element */                     \
  95 }
  96
  97 #define SLIST_HEAD_INITIALIZER(head)                                    \
  98         { NULL }
  99
 100 #define SLIST_ENTRY(type)                                               \
 101 struct {                                                                \
 102         struct type *sle_next;  /* next element */                      \
 103 }
 104
 105 /*
 106  * Singly-linked List access methods.
 107  */
 108 #define SLIST_FIRST(head)       ((head)->slh_first)
 109 #define SLIST_END(head)         NULL
 110 #define SLIST_EMPTY(head)       (SLIST_FIRST(head) == SLIST_END(head))
 111 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 112
 113 #define SLIST_FOREACH(var, head, field)                                 \
 114         for((var) = SLIST_FIRST(head);                                  \
 115             (var) != SLIST_END(head);                                   \
 116             (var) = SLIST_NEXT(var, field))
 117
 118 /*
 119  * Singly-linked List functions.
 120  */
 121 #define SLIST_INIT(head) {                                              \
 122         SLIST_FIRST(head) = SLIST_END(head);                            \
 123 }
 124
 125 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 126         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 127         (slistelm)->field.sle_next = (elm);                             \
 128 } while (0)
 129
 130 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 131         (elm)->field.sle_next = (head)->slh_first;                      \
 132         (head)->slh_first = (elm);                                      \
 133 } while (0)
 134
 135 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 136         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 137 } while (0)
 138
 139 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 140         if ((head)->slh_first == (elm)) {                               \
 141                 SLIST_REMOVE_HEAD((head), field);                       \
 142         }                                                               \
 143         else {                                                          \
 144                 struct type *curelm = (head)->slh_first;                \
 145                 while( curelm->field.sle_next != (elm) )                \
 146                         curelm = curelm->field.sle_next;                \
 147                 curelm->field.sle_next =                                \
 148                     curelm->field.sle_next->field.sle_next;             \
 149         }                                                               \
 150 } while (0)
 151
 152 /*
 153  * List definitions.
 154  */
 155 #define LIST_HEAD(name, type)                                           \
 156 struct name {                                                           \
 157         struct type *lh_first;  /* first element */                     \
 158 }
 159
 160 #define LIST_HEAD_INITIALIZER(head)                                     \
 161         { NULL }
 162
 163 #define LIST_ENTRY(type)                                                \
 164 struct {                                                                \
 165         struct type *le_next;   /* next element */                      \
 166         struct type **le_prev;  /* address of previous next element */  \
 167 }
 168
 169 /*
 170  * List access methods
 171  */
 172 #define LIST_FIRST(head)                ((head)->lh_first)
 173 #define LIST_END(head)                  NULL
 174 #define LIST_EMPTY(head)                (LIST_FIRST(head) == LIST_END(head))
 175 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 176
 177 #define LIST_FOREACH(var, head, field)                                  \
 178         for((var) = LIST_FIRST(head);                                   \
 179             (var)!= LIST_END(head);                                     \
 180             (var) = LIST_NEXT(var, field))
 181
 182 /*
 183  * List functions.
 184  */
 185 #define LIST_INIT(head) do {                                            \
 186         LIST_FIRST(head) = LIST_END(head);                              \
 187 } while (0)
 188
 189 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 190         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 191                 (listelm)->field.le_next->field.le_prev =               \
 192                     &(elm)->field.le_next;                              \
 193         (listelm)->field.le_next = (elm);                               \
 194         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 195 } while (0)
 196
 197 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 198         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 199         (elm)->field.le_next = (listelm);                               \
 200         *(listelm)->field.le_prev = (elm);                              \
 201         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 202 } while (0)
 203
 204 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 205         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 206                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 207         (head)->lh_first = (elm);                                       \
 208         (elm)->field.le_prev = &(head)->lh_first;                       \
 209 } while (0)
 210
 211 #define LIST_REMOVE(elm, field) do {                                    \
 212         if ((elm)->field.le_next != NULL)                               \
 213                 (elm)->field.le_next->field.le_prev =                   \
 214                     (elm)->field.le_prev;                               \
 215         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 216 } while (0)
 217
 218 #define LIST_REPLACE(elm, elm2, field) do {                             \
 219         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 220                 (elm2)->field.le_next->field.le_prev =                  \
 221                     &(elm2)->field.le_next;                             \
 222         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 223         *(elm2)->field.le_prev = (elm2);                                \
 224 } while (0)
 225
 226 /*
 227  * Simple queue definitions.
 228  */
 229 #define SIMPLEQ_HEAD(name, type)                                        \
 230 struct name {                                                           \
 231         struct type *sqh_first; /* first element */                     \
 232         struct type **sqh_last; /* addr of last next element */         \
 233 }
 234
 235 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 236         { NULL, &(head).sqh_first }
 237
 238 #define SIMPLEQ_ENTRY(type)                                             \
 239 struct {                                                                \
 240         struct type *sqe_next;  /* next element */                      \
 241 }
 242
 243 /*
 244  * Simple queue access methods.
 245  */
 246 #define SIMPLEQ_FIRST(head)         ((head)->sqh_first)
 247 #define SIMPLEQ_END(head)           NULL
 248 #define SIMPLEQ_EMPTY(head)         (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 249 #define SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 250
 251 #define SIMPLEQ_FOREACH(var, head, field)                               \
 252         for((var) = SIMPLEQ_FIRST(head);                                \
 253             (var) != SIMPLEQ_END(head);                                 \
 254             (var) = SIMPLEQ_NEXT(var, field))
 255
 256 /*
 257  * Simple queue functions.
 258  */
 259 #define SIMPLEQ_INIT(head) do {                                         \
 260         (head)->sqh_first = NULL;                                       \
 261         (head)->sqh_last = &(head)->sqh_first;                          \
 262 } while (0)
 263
 264 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 265         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 266                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 267         (head)->sqh_first = (elm);                                      \
 268 } while (0)
 269
 270 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 271         (elm)->field.sqe_next = NULL;                                   \
 272         *(head)->sqh_last = (elm);                                      \
 273         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 274 } while (0)
 275
 276 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 277         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 278                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 279         (listelm)->field.sqe_next = (elm);                              \
 280 } while (0)
 281
 282 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {                      \
 283         if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)        \
 284                 (head)->sqh_last = &(head)->sqh_first;                  \
 285 } while (0)
 286
 287 /*
 288  * Tail queue definitions.
 289  */
 290 #define TAILQ_HEAD(name, type)                                          \
 291 struct name {                                                           \
 292         struct type *tqh_first; /* first element */                     \
 293         struct type **tqh_last; /* addr of last next element */         \
 294 }
 295
 296 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 297         { NULL, &(head).tqh_first }
 298
 299 #define TAILQ_ENTRY(type)                                               \
 300 struct {                                                                \
 301         struct type *tqe_next;  /* next element */                      \
 302         struct type **tqe_prev; /* address of previous next element */  \
 303 }
 304
 305 /*
 306  * tail queue access methods
 307  */
 308 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 309 #define TAILQ_END(head)                 NULL
 310 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 311 #define TAILQ_LAST(head, headname)                                      \
 312         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 313 /* XXX */
 314 #define TAILQ_PREV(elm, headname, field)                                \
 315         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 316 #define TAILQ_EMPTY(head)                                               \
 317         (TAILQ_FIRST(head) == TAILQ_END(head))
 318
 319 #define TAILQ_FOREACH(var, head, field)                                 \
 320         for((var) = TAILQ_FIRST(head);                                  \
 321             (var) != TAILQ_END(head);                                   \
 322             (var) = TAILQ_NEXT(var, field))
 323
 324 #define TAILQ_FOREACH_REVERSE(var, head, field, headname)               \
 325         for((var) = TAILQ_LAST(head, headname);                         \
 326             (var) != TAILQ_END(head);                                   \
 327             (var) = TAILQ_PREV(var, headname, field))
 328
 329 /*
 330  * Tail queue functions.
 331  */
 332 #define TAILQ_INIT(head) do {                                           \
 333         (head)->tqh_first = NULL;                                       \
 334         (head)->tqh_last = &(head)->tqh_first;                          \
 335 } while (0)
 336
 337 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 338         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 339                 (head)->tqh_first->field.tqe_prev =                     \
 340                     &(elm)->field.tqe_next;                             \
 341         else                                                            \
 342                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 343         (head)->tqh_first = (elm);                                      \
 344         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 345 } while (0)
 346
 347 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 348         (elm)->field.tqe_next = NULL;                                   \
 349         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 350         *(head)->tqh_last = (elm);                                      \
 351         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 352 } while (0)
 353
 354 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 355         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 356                 (elm)->field.tqe_next->field.tqe_prev =                 \
 357                     &(elm)->field.tqe_next;                             \
 358         else                                                            \
 359                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 360         (listelm)->field.tqe_next = (elm);                              \
 361         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 362 } while (0)
 363
 364 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 365         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 366         (elm)->field.tqe_next = (listelm);                              \
 367         *(listelm)->field.tqe_prev = (elm);                             \
 368         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 369 } while (0)
 370
 371 #define TAILQ_REMOVE(head, elm, field) do {                             \
 372         if (((elm)->field.tqe_next) != NULL)                            \
 373                 (elm)->field.tqe_next->field.tqe_prev =                 \
 374                     (elm)->field.tqe_prev;                              \
 375         else                                                            \
 376                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 377         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 378 } while (0)
 379
 380 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 381         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 382                 (elm2)->field.tqe_next->field.tqe_prev =                \
 383                     &(elm2)->field.tqe_next;                            \
 384         else                                                            \
 385                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 386         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 387         *(elm2)->field.tqe_prev = (elm2);                               \
 388 } while (0)
 389
 390 /*
 391  * Circular queue definitions.
 392  */
 393 #define CIRCLEQ_HEAD(name, type)                                        \
 394 struct name {                                                           \
 395         struct type *cqh_first;         /* first element */             \
 396         struct type *cqh_last;          /* last element */              \
 397 }
 398
 399 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 400         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 401
 402 #define CIRCLEQ_ENTRY(type)                                             \
 403 struct {                                                                \
 404         struct type *cqe_next;          /* next element */              \
 405         struct type *cqe_prev;          /* previous element */          \
 406 }
 407
 408 /*
 409  * Circular queue access methods
 410  */
 411 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 412 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 413 #define CIRCLEQ_END(head)               ((void *)(head))
 414 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 415 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 416 #define CIRCLEQ_EMPTY(head)                                             \
 417         (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
 418
 419 #define CIRCLEQ_FOREACH(var, head, field)                               \
 420         for((var) = CIRCLEQ_FIRST(head);                                \
 421             (var) != CIRCLEQ_END(head);                                 \
 422             (var) = CIRCLEQ_NEXT(var, field))
 423
 424 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 425         for((var) = CIRCLEQ_LAST(head);                                 \
 426             (var) != CIRCLEQ_END(head);                                 \
 427             (var) = CIRCLEQ_PREV(var, field))
 428
 429 /*
 430  * Circular queue functions.
 431  */
 432 #define CIRCLEQ_INIT(head) do {                                         \
 433         (head)->cqh_first = CIRCLEQ_END(head);                          \
 434         (head)->cqh_last = CIRCLEQ_END(head);                           \
 435 } while (0)
 436
 437 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 438         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 439         (elm)->field.cqe_prev = (listelm);                              \
 440         if ((listelm)->field.cqe_next == CIRCLEQ_END(head))             \
 441                 (head)->cqh_last = (elm);                               \
 442         else                                                            \
 443                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 444         (listelm)->field.cqe_next = (elm);                              \
 445 } while (0)
 446
 447 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 448         (elm)->field.cqe_next = (listelm);                              \
 449         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 450         if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))             \
 451                 (head)->cqh_first = (elm);                              \
 452         else                                                            \
 453                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 454         (listelm)->field.cqe_prev = (elm);                              \
 455 } while (0)
 456
 457 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 458         (elm)->field.cqe_next = (head)->cqh_first;                      \
 459         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 460         if ((head)->cqh_last == CIRCLEQ_END(head))                      \
 461                 (head)->cqh_last = (elm);                               \
 462         else                                                            \
 463                 (head)->cqh_first->field.cqe_prev = (elm);              \
 464         (head)->cqh_first = (elm);                                      \
 465 } while (0)
 466
 467 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 468         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 469         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 470         if ((head)->cqh_first == CIRCLEQ_END(head))                     \
 471                 (head)->cqh_first = (elm);                              \
 472         else                                                            \
 473                 (head)->cqh_last->field.cqe_next = (elm);               \
 474         (head)->cqh_last = (elm);                                       \
 475 } while (0)
 476
 477 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 478         if ((elm)->field.cqe_next == CIRCLEQ_END(head))                 \
 479                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 480         else                                                            \
 481                 (elm)->field.cqe_next->field.cqe_prev =                 \
 482                     (elm)->field.cqe_prev;                              \
 483         if ((elm)->field.cqe_prev == CIRCLEQ_END(head))                 \
 484                 (head)->cqh_first = (elm)->field.cqe_next;              \
 485         else                                                            \
 486                 (elm)->field.cqe_prev->field.cqe_next =                 \
 487                     (elm)->field.cqe_next;                              \
 488 } while (0)
 489
 490 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do {                    \
 491         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 492             CIRCLEQ_END(head))                                          \
 493                 (head).cqh_last = (elm2);                               \
 494         else                                                            \
 495                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 496         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 497             CIRCLEQ_END(head))                                          \
 498                 (head).cqh_first = (elm2);                              \
 499         else                                                            \
 500                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 501 } while (0)
 502
 503 #endif  /* !_SYS_QUEUE_H_ */