src/kits/network/netresolv/include/isc/list.h

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1997,1999 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
  18 #ifndef LIST_H
  19 #define LIST_H 1
  20 #include <isc/assertions.h>
  21
  22 #define LIST(type) struct { type *head, *tail; }
  23 #define INIT_LIST(list) \
  24         do { (list).head = NULL; (list).tail = NULL; } while (0)
  25
  26 #define LINK(type) struct { type *prev, *next; }
  27 #define INIT_LINK_TYPE(elt, link, type) \
  28         do { \
  29                 (elt)->link.prev = (type *)(-1); \
  30                 (elt)->link.next = (type *)(-1); \
  31         } while (0)
  32 #define INIT_LINK(elt, link) \
  33         INIT_LINK_TYPE(elt, link, void)
  34 #define LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1) && \
  35                            (void *)((elt)->link.next) != (void *)(-1))
  36
  37 #define HEAD(list) ((list).head)
  38 #define TAIL(list) ((list).tail)
  39 #define EMPTY(list) ((list).head == NULL)
  40
  41 #define PREPEND(list, elt, link) \
  42         do { \
  43                 INSIST(!LINKED(elt, link));\
  44                 if ((list).head != NULL) \
  45                         (list).head->link.prev = (elt); \
  46                 else \
  47                         (list).tail = (elt); \
  48                 (elt)->link.prev = NULL; \
  49                 (elt)->link.next = (list).head; \
  50                 (list).head = (elt); \
  51         } while (0)
  52
  53 #define APPEND(list, elt, link) \
  54         do { \
  55                 INSIST(!LINKED(elt, link));\
  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 UNLINK_TYPE(list, elt, link, type) \
  66         do { \
  67                 INSIST(LINKED(elt, link));\
  68                 if ((elt)->link.next != NULL) \
  69                         (elt)->link.next->link.prev = (elt)->link.prev; \
  70                 else { \
  71                         INSIST((list).tail == (elt)); \
  72                         (list).tail = (elt)->link.prev; \
  73                 } \
  74                 if ((elt)->link.prev != NULL) \
  75                         (elt)->link.prev->link.next = (elt)->link.next; \
  76                 else { \
  77                         INSIST((list).head == (elt)); \
  78                         (list).head = (elt)->link.next; \
  79                 } \
  80                 INIT_LINK_TYPE(elt, link, type); \
  81         } while (0)
  82 #define UNLINK(list, elt, link) \
  83         UNLINK_TYPE(list, elt, link, void)
  84
  85 #define PREV(elt, link) ((elt)->link.prev)
  86 #define NEXT(elt, link) ((elt)->link.next)
  87
  88 #define INSERT_BEFORE(list, before, elt, link) \
  89         do { \
  90                 INSIST(!LINKED(elt, link));\
  91                 if ((before)->link.prev == NULL) \
  92                         PREPEND(list, elt, link); \
  93                 else { \
  94                         (elt)->link.prev = (before)->link.prev; \
  95                         (before)->link.prev = (elt); \
  96                         (elt)->link.prev->link.next = (elt); \
  97                         (elt)->link.next = (before); \
  98                 } \
  99         } while (0)
 100
 101 #define INSERT_AFTER(list, after, elt, link) \
 102         do { \
 103                 INSIST(!LINKED(elt, link));\
 104                 if ((after)->link.next == NULL) \
 105                         APPEND(list, elt, link); \
 106                 else { \
 107                         (elt)->link.next = (after)->link.next; \
 108                         (after)->link.next = (elt); \
 109                         (elt)->link.next->link.prev = (elt); \
 110                         (elt)->link.prev = (after); \
 111                 } \
 112         } while (0)
 113
 114 #define ENQUEUE(list, elt, link) APPEND(list, elt, link)
 115 #define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
 116
 117 #endif /* LIST_H */
 118 /*! \file */