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C/C++ Source or Header  |  1996-02-19  |  9KB  |  260 lines
  1. /* 
  2.  * Copyright (c) 1991, 1993
  3.  *    The Regents of the University of California.  All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  * 1. Redistributions of source code must retain the above copyright
  9.  *    notice, this list of conditions and the following disclaimer.
  10.  * 2. Redistributions in binary form must reproduce the above copyright
  11.  *    notice, this list of conditions and the following disclaimer in the
  12.  *    documentation and/or other materials provided with the distribution.
  13.  * 3. All advertising materials mentioning features or use of this software
  14.  *    must display the following acknowledgement:
  15.  *    This product includes software developed by the University of
  16.  *    California, Berkeley and its contributors.
  17.  * 4. Neither the name of the University nor the names of its contributors
  18.  *    may be used to endorse or promote products derived from this software
  19.  *    without specific prior written permission.
  20.  *
  21.  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22.  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25.  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26.  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27.  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28.  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29.  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30.  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31.  * SUCH DAMAGE.
  32.  *
  33.  *    @(#)queue.h    8.5 (Berkeley) 8/20/94
  34.  */
  35.  
  36. #ifndef    _SYS_QUEUE_H_
  37. #define    _SYS_QUEUE_H_
  38.  
  39. /*
  40.  * This file defines three types of data structures: lists, tail queues,
  41.  * and circular queues.
  42.  *
  43.  * A list is headed by a single forward pointer (or an array of forward
  44.  * pointers for a hash table header). The elements are doubly linked
  45.  * so that an arbitrary element can be removed without a need to
  46.  * traverse the list. New elements can be added to the list before
  47.  * or after an existing element or at the head of the list. A list
  48.  * may only be traversed in the forward direction.
  49.  *
  50.  * A tail queue is headed by a pair of pointers, one to the head of the
  51.  * list and the other to the tail of the list. The elements are doubly
  52.  * linked so that an arbitrary element can be removed without a need to
  53.  * traverse the list. New elements can be added to the list before or
  54.  * after an existing element, at the head of the list, or at the end of
  55.  * the list. A tail queue may only be traversed in the forward direction.
  56.  *
  57.  * A circle queue is headed by a pair of pointers, one to the head of the
  58.  * list and the other to the tail of the list. The elements are doubly
  59.  * linked 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 or after
  61.  * an existing element, at the head of the list, or at the end of the list.
  62.  * A circle queue may be traversed in either direction, but has a more
  63.  * complex end of list detection.
  64.  *
  65.  * For details on the use of these macros, see the queue(3) manual page.
  66.  */
  67.  
  68. /*
  69.  * List definitions.
  70.  */
  71. #define LIST_HEAD(name, type)                        \
  72. struct name {                                \
  73.     struct type *lh_first;    /* first element */            \
  74. }
  75.  
  76. #define LIST_ENTRY(type)                        \
  77. struct {                                \
  78.     struct type *le_next;    /* next element */            \
  79.     struct type **le_prev;    /* address of previous next element */    \
  80. }
  81.  
  82. /*
  83.  * List functions.
  84.  */
  85. #define    LIST_INIT(head) {                        \
  86.     (head)->lh_first = NULL;                    \
  87. }
  88.  
  89. #define LIST_INSERT_AFTER(listelm, elm, field) {            \
  90.     if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)    \
  91.         (listelm)->field.le_next->field.le_prev =        \
  92.             &(elm)->field.le_next;                \
  93.     (listelm)->field.le_next = (elm);                \
  94.     (elm)->field.le_prev = &(listelm)->field.le_next;        \
  95. }
  96.  
  97. #define    LIST_INSERT_BEFORE(listelm, elm, field) {            \
  98.     (elm)->field.le_prev = (listelm)->field.le_prev;        \
  99.     (elm)->field.le_next = (listelm);                \
  100.     *(listelm)->field.le_prev = (elm);                \
  101.     (listelm)->field.le_prev = &(elm)->field.le_next;        \
  102. }
  103.  
  104. #define LIST_INSERT_HEAD(head, elm, field) {                \
  105.     if (((elm)->field.le_next = (head)->lh_first) != NULL)        \
  106.         (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
  107.     (head)->lh_first = (elm);                    \
  108.     (elm)->field.le_prev = &(head)->lh_first;            \
  109. }
  110.  
  111. #define LIST_REMOVE(elm, field) {                    \
  112.     if ((elm)->field.le_next != NULL)                \
  113.         (elm)->field.le_next->field.le_prev =             \
  114.             (elm)->field.le_prev;                \
  115.     *(elm)->field.le_prev = (elm)->field.le_next;            \
  116. }
  117.  
  118. /*
  119.  * Tail queue definitions.
  120.  */
  121. #define TAILQ_HEAD(name, type)                        \
  122. struct name {                                \
  123.     struct type *tqh_first;    /* first element */            \
  124.     struct type **tqh_last;    /* addr of last next element */        \
  125. }
  126.  
  127. #define TAILQ_ENTRY(type)                        \
  128. struct {                                \
  129.     struct type *tqe_next;    /* next element */            \
  130.     struct type **tqe_prev;    /* address of previous next element */    \
  131. }
  132.  
  133. /*
  134.  * Tail queue functions.
  135.  */
  136. #define    TAILQ_INIT(head) {                        \
  137.     (head)->tqh_first = NULL;                    \
  138.     (head)->tqh_last = &(head)->tqh_first;                \
  139. }
  140.  
  141. #define TAILQ_INSERT_HEAD(head, elm, field) {                \
  142.     if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)    \
  143.         (head)->tqh_first->field.tqe_prev =            \
  144.             &(elm)->field.tqe_next;                \
  145.     else                                \
  146.         (head)->tqh_last = &(elm)->field.tqe_next;        \
  147.     (head)->tqh_first = (elm);                    \
  148.     (elm)->field.tqe_prev = &(head)->tqh_first;            \
  149. }
  150.  
  151. #define TAILQ_INSERT_TAIL(head, elm, field) {                \
  152.     (elm)->field.tqe_next = NULL;                    \
  153.     (elm)->field.tqe_prev = (head)->tqh_last;            \
  154.     *(head)->tqh_last = (elm);                    \
  155.     (head)->tqh_last = &(elm)->field.tqe_next;            \
  156. }
  157.  
  158. #define TAILQ_INSERT_AFTER(head, listelm, elm, field) {            \
  159.     if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
  160.         (elm)->field.tqe_next->field.tqe_prev =         \
  161.             &(elm)->field.tqe_next;                \
  162.     else                                \
  163.         (head)->tqh_last = &(elm)->field.tqe_next;        \
  164.     (listelm)->field.tqe_next = (elm);                \
  165.     (elm)->field.tqe_prev = &(listelm)->field.tqe_next;        \
  166. }
  167.  
  168. #define    TAILQ_INSERT_BEFORE(listelm, elm, field) {            \
  169.     (elm)->field.tqe_prev = (listelm)->field.tqe_prev;        \
  170.     (elm)->field.tqe_next = (listelm);                \
  171.     *(listelm)->field.tqe_prev = (elm);                \
  172.     (listelm)->field.tqe_prev = &(elm)->field.tqe_next;        \
  173. }
  174.  
  175. #define TAILQ_REMOVE(head, elm, field) {                \
  176.     if (((elm)->field.tqe_next) != NULL)                \
  177.         (elm)->field.tqe_next->field.tqe_prev =         \
  178.             (elm)->field.tqe_prev;                \
  179.     else                                \
  180.         (head)->tqh_last = (elm)->field.tqe_prev;        \
  181.     *(elm)->field.tqe_prev = (elm)->field.tqe_next;            \
  182. }
  183.  
  184. /*
  185.  * Circular queue definitions.
  186.  */
  187. #define CIRCLEQ_HEAD(name, type)                    \
  188. struct name {                                \
  189.     struct type *cqh_first;        /* first element */        \
  190.     struct type *cqh_last;        /* last element */        \
  191. }
  192.  
  193. #define CIRCLEQ_ENTRY(type)                        \
  194. struct {                                \
  195.     struct type *cqe_next;        /* next element */        \
  196.     struct type *cqe_prev;        /* previous element */        \
  197. }
  198.  
  199. /*
  200.  * Circular queue functions.
  201.  */
  202. #define    CIRCLEQ_INIT(head) {                        \
  203.     (head)->cqh_first = (void *)(head);                \
  204.     (head)->cqh_last = (void *)(head);                \
  205. }
  206.  
  207. #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) {        \
  208.     (elm)->field.cqe_next = (listelm)->field.cqe_next;        \
  209.     (elm)->field.cqe_prev = (listelm);                \
  210.     if ((listelm)->field.cqe_next == (void *)(head))        \
  211.         (head)->cqh_last = (elm);                \
  212.     else                                \
  213.         (listelm)->field.cqe_next->field.cqe_prev = (elm);    \
  214.     (listelm)->field.cqe_next = (elm);                \
  215. }
  216.  
  217. #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) {        \
  218.     (elm)->field.cqe_next = (listelm);                \
  219.     (elm)->field.cqe_prev = (listelm)->field.cqe_prev;        \
  220.     if ((listelm)->field.cqe_prev == (void *)(head))        \
  221.         (head)->cqh_first = (elm);                \
  222.     else                                \
  223.         (listelm)->field.cqe_prev->field.cqe_next = (elm);    \
  224.     (listelm)->field.cqe_prev = (elm);                \
  225. }
  226.  
  227. #define CIRCLEQ_INSERT_HEAD(head, elm, field) {                \
  228.     (elm)->field.cqe_next = (head)->cqh_first;            \
  229.     (elm)->field.cqe_prev = (void *)(head);                \
  230.     if ((head)->cqh_last == (void *)(head))                \
  231.         (head)->cqh_last = (elm);                \
  232.     else                                \
  233.         (head)->cqh_first->field.cqe_prev = (elm);        \
  234.     (head)->cqh_first = (elm);                    \
  235. }
  236.  
  237. #define CIRCLEQ_INSERT_TAIL(head, elm, field) {                \
  238.     (elm)->field.cqe_next = (void *)(head);                \
  239.     (elm)->field.cqe_prev = (head)->cqh_last;            \
  240.     if ((head)->cqh_first == (void *)(head))            \
  241.         (head)->cqh_first = (elm);                \
  242.     else                                \
  243.         (head)->cqh_last->field.cqe_next = (elm);        \
  244.     (head)->cqh_last = (elm);                    \
  245. }
  246.  
  247. #define    CIRCLEQ_REMOVE(head, elm, field) {                \
  248.     if ((elm)->field.cqe_next == (void *)(head))            \
  249.         (head)->cqh_last = (elm)->field.cqe_prev;        \
  250.     else                                \
  251.         (elm)->field.cqe_next->field.cqe_prev =            \
  252.             (elm)->field.cqe_prev;                \
  253.     if ((elm)->field.cqe_prev == (void *)(head))            \
  254.         (head)->cqh_first = (elm)->field.cqe_next;        \
  255.     else                                \
  256.         (elm)->field.cqe_prev->field.cqe_next =            \
  257.             (elm)->field.cqe_next;                \
  258. }
  259. #endif    /* !_SYS_QUEUE_H_ */
  260.