contrib/dhcp-3.0/includes/isc-dhcp/list.h

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1997-2003 by Internet Software Consortium
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  *
  17  *   Internet Systems Consortium, Inc.
  18  *   950 Charter Street
  19  *   Redwood City, CA 94063
  20  *   <info@isc.org>
  21  *   http://www.isc.org/
  22  */
  23
  24 #ifndef ISC_LIST_H
  25 #define ISC_LIST_H 1
  26
  27 #define ISC_LIST(type) struct { type *head, *tail; }
  28 #define ISC_LIST_INIT(list) \
  29         do { (list).head = NULL; (list).tail = NULL; } while (0)
  30
  31 #define ISC_LINK(type) struct { type *prev, *next; }
  32 #define ISC_LINK_INIT(elt, link) \
  33         do { \
  34                 (elt)->link.prev = (void *)(-1); \
  35                 (elt)->link.next = (void *)(-1); \
  36         } while (0)
  37 #define ISC_LINK_LINKED(elt, link) ((elt)->link.prev != (void *)(-1))
  38
  39 #define ISC_LIST_HEAD(list) ((list).head)
  40 #define ISC_LIST_TAIL(list) ((list).tail)
  41 #define ISC_LIST_EMPTY(list) ((list).head == NULL)
  42
  43 #define ISC_LIST_PREPEND(list, elt, link) \
  44         do { \
  45                 if ((list).head != NULL) \
  46                         (list).head->link.prev = (elt); \
  47                 else \
  48                         (list).tail = (elt); \
  49                 (elt)->link.prev = NULL; \
  50                 (elt)->link.next = (list).head; \
  51                 (list).head = (elt); \
  52         } while (0)
  53
  54 #define ISC_LIST_APPEND(list, elt, link) \
  55         do { \
  56                 if ((list).tail != NULL) \
  57                         (list).tail->link.next = (elt); \
  58                 else \
  59                         (list).head = (elt); \
  60                 (elt)->link.prev = (list).tail; \
  61                 (elt)->link.next = NULL; \
  62                 (list).tail = (elt); \
  63         } while (0)
  64
  65 #define ISC_LIST_UNLINK(list, elt, link) \
  66         do { \
  67                 if ((elt)->link.next != NULL) \
  68                         (elt)->link.next->link.prev = (elt)->link.prev; \
  69                 else \
  70                         (list).tail = (elt)->link.prev; \
  71                 if ((elt)->link.prev != NULL) \
  72                         (elt)->link.prev->link.next = (elt)->link.next; \
  73                 else \
  74                         (list).head = (elt)->link.next; \
  75                 (elt)->link.prev = (void *)(-1); \
  76                 (elt)->link.next = (void *)(-1); \
  77         } while (0)
  78
  79 #define ISC_LIST_PREV(elt, link) ((elt)->link.prev)
  80 #define ISC_LIST_NEXT(elt, link) ((elt)->link.next)
  81
  82 #define ISC_LIST_INSERTBEFORE(list, before, elt, link) \
  83         do { \
  84                 if ((before)->link.prev == NULL) \
  85                         ISC_LIST_PREPEND(list, elt, link); \
  86                 else { \
  87                         (elt)->link.prev = (before)->link.prev; \
  88                         (before)->link.prev = (elt); \
  89                         (elt)->link.prev->link.next = (elt); \
  90                         (elt)->link.next = (before); \
  91                 } \
  92         } while (0)
  93
  94 #define ISC_LIST_INSERTAFTER(list, after, elt, link) \
  95         do { \
  96                 if ((after)->link.next == NULL) \
  97                         ISC_LIST_APPEND(list, elt, link); \
  98                 else { \
  99                         (elt)->link.next = (after)->link.next; \
 100                         (after)->link.next = (elt); \
 101                         (elt)->link.next->link.prev = (elt); \
 102                         (elt)->link.prev = (after); \
 103                 } \
 104         } while (0)
 105
 106 #define ISC_LIST_APPENDLIST(list1, list2, link) \
 107         do { \
 108                 if (ISC_LIST_EMPTY(list1)) \
 109                         (list1) = (list2); \
 110                 else if (!ISC_LIST_EMPTY(list2)) { \
 111                         (list1).tail->link.next = (list2).head; \
 112                         (list2).head->link.prev = (list1).tail; \
 113                         (list1).tail = (list2).tail; \
 114                         (list2).head = NULL; \
 115                         (list2).tail = NULL; \
 116                 } \
 117         } while (0)
 118
 119 #define ISC_LIST_ENQUEUE(list, elt, link) ISC_LIST_APPEND(list, elt, link)
 120 #define ISC_LIST_DEQUEUE(list, elt, link) ISC_LIST_UNLINK(list, elt, link)
 121
 122 #endif /* ISC_LIST_H */