lib/libc/include/isc/list.h

   1 /*      $NetBSD: list.h,v 1.5 2009/04/12 17:07:16 christos Exp $        */
   2
   3 /*
   4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (c) 1997,1999 by Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #ifndef LIST_H
  21 #define LIST_H 1
  22 #include <isc/assertions.h>
  23
  24 #define LIST(type) struct { type *head, *tail; }
  25 #define INIT_LIST(list) \
  26         do { (list).head = NULL; (list).tail = NULL; } while (/*CONSTCOND*/0)
  27
  28 #define LINK(type) struct { type *prev, *next; }
  29 #define INIT_LINK_TYPE(elt, link, type) \
  30         do { \
  31                 (elt)->link.prev = (type *)(-1); \
  32                 (elt)->link.next = (type *)(-1); \
  33         } while (/*CONSTCOND*/0)
  34 #define INIT_LINK(elt, link) \
  35         INIT_LINK_TYPE(elt, link, void)
  36 #define LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1) && \
  37                            (void *)((elt)->link.next) != (void *)(-1))
  38
  39 #define HEAD(list) ((list).head)
  40 #define TAIL(list) ((list).tail)
  41 #define EMPTY(list) ((list).head == NULL)
  42
  43 #define PREPEND(list, elt, link) \
  44         do { \
  45                 INSIST(!LINKED(elt, link));\
  46                 if ((list).head != NULL) \
  47                         (list).head->link.prev = (elt); \
  48                 else \
  49                         (list).tail = (elt); \
  50                 (elt)->link.prev = NULL; \
  51                 (elt)->link.next = (list).head; \
  52                 (list).head = (elt); \
  53         } while (/*CONSTCOND*/0)
  54
  55 #define APPEND(list, elt, link) \
  56         do { \
  57                 INSIST(!LINKED(elt, link));\
  58                 if ((list).tail != NULL) \
  59                         (list).tail->link.next = (elt); \
  60                 else \
  61                         (list).head = (elt); \
  62                 (elt)->link.prev = (list).tail; \
  63                 (elt)->link.next = NULL; \
  64                 (list).tail = (elt); \
  65         } while (/*CONSTCOND*/0)
  66
  67 #define UNLINK_TYPE(list, elt, link, type) \
  68         do { \
  69                 INSIST(LINKED(elt, link));\
  70                 if ((elt)->link.next != NULL) \
  71                         (elt)->link.next->link.prev = (elt)->link.prev; \
  72                 else { \
  73                         INSIST((list).tail == (elt)); \
  74                         (list).tail = (elt)->link.prev; \
  75                 } \
  76                 if ((elt)->link.prev != NULL) \
  77                         (elt)->link.prev->link.next = (elt)->link.next; \
  78                 else { \
  79                         INSIST((list).head == (elt)); \
  80                         (list).head = (elt)->link.next; \
  81                 } \
  82                 INIT_LINK_TYPE(elt, link, type); \
  83         } while (/*CONSTCOND*/0)
  84 #define UNLINK(list, elt, link) \
  85         UNLINK_TYPE(list, elt, link, void)
  86
  87 #define PREV(elt, link) ((elt)->link.prev)
  88 #define NEXT(elt, link) ((elt)->link.next)
  89
  90 #define INSERT_BEFORE(list, before, elt, link) \
  91         do { \
  92                 INSIST(!LINKED(elt, link));\
  93                 if ((before)->link.prev == NULL) \
  94                         PREPEND(list, elt, link); \
  95                 else { \
  96                         (elt)->link.prev = (before)->link.prev; \
  97                         (before)->link.prev = (elt); \
  98                         (elt)->link.prev->link.next = (elt); \
  99                         (elt)->link.next = (before); \
 100                 } \
 101         } while (/*CONSTCOND*/0)
 102
 103 #define INSERT_AFTER(list, after, elt, link) \
 104         do { \
 105                 INSIST(!LINKED(elt, link));\
 106                 if ((after)->link.next == NULL) \
 107                         APPEND(list, elt, link); \
 108                 else { \
 109                         (elt)->link.next = (after)->link.next; \
 110                         (after)->link.next = (elt); \
 111                         (elt)->link.next->link.prev = (elt); \
 112                         (elt)->link.prev = (after); \
 113                 } \
 114         } while (/*CONSTCOND*/0)
 115
 116 #define ENQUEUE(list, elt, link) APPEND(list, elt, link)
 117 #define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
 118
 119 #endif /* LIST_H */
 120 /*! \file */