lib/linklist.h

   1 /* Generic linked list
   2  * Copyright (C) 1997, 2000 Kunihiro Ishiguro
   3  *
   4  * This file is part of GNU Zebra.
   5  *
   6  * GNU Zebra is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * GNU Zebra is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef _ZEBRA_LINKLIST_H
  22 #define _ZEBRA_LINKLIST_H
  23
  24 /* listnodes must always contain data to be valid. Adding an empty node
  25  * to a list is invalid
  26  */
  27 struct listnode
  28 {
  29   struct listnode *next;
  30   struct listnode *prev;
  31
  32   /* private member, use getdata() to retrieve, do not access directly */
  33   void *data;
  34 };
  35
  36 struct list
  37 {
  38   struct listnode *head;
  39   struct listnode *tail;
  40
  41   /* invariant: count is the number of listnodes in the list */
  42   unsigned int count;
  43
  44   /*
  45    * Returns -1 if val1 < val2, 0 if equal?, 1 if val1 > val2.
  46    * Used as definition of sorted for listnode_add_sort
  47    */
  48   int (*cmp) (void *val1, void *val2);
  49
  50   /* callback to free user-owned data when listnode is deleted. supplying
  51    * this callback is very much encouraged!
  52    */
  53   void (*del) (void *val);
  54 };
  55
  56 #define listnextnode(X) ((X) ? ((X)->next) : NULL)
  57 #define listhead(X) ((X) ? ((X)->head) : NULL)
  58 #define listtail(X) ((X) ? ((X)->tail) : NULL)
  59 #define listcount(X) ((X)->count)
  60 #define list_isempty(X) ((X)->head == NULL && (X)->tail == NULL)
  61 #define listgetdata(X) (assert((X)->data != NULL), (X)->data)
  62
  63 /* Prototypes. */
  64 extern struct list *list_new(void); /* encouraged: set list.del callback on new lists */
  65 extern void list_free (struct list *);
  66
  67 extern void listnode_add (struct list *, void *);
  68 extern void listnode_add_sort (struct list *, void *);
  69 extern struct listnode *listnode_add_after (struct list *, struct listnode *, void *);
  70 extern struct listnode *listnode_add_before (struct list *, struct listnode *, void *);
  71 extern void listnode_move_to_tail (struct list *, struct listnode *);
  72 extern void listnode_delete (struct list *, void *);
  73 extern struct listnode *listnode_lookup (struct list *, void *);
  74 extern void *listnode_head (struct list *);
  75
  76 extern void list_delete (struct list *);
  77 extern void list_delete_all_node (struct list *);
  78
  79 /* For ospfd and ospf6d. */
  80 extern void list_delete_node (struct list *, struct listnode *);
  81
  82 /* For ospf_spf.c */
  83 extern void list_add_list (struct list *, struct list *);
  84
  85 /* List iteration macro.
  86  * Usage: for (ALL_LIST_ELEMENTS (...) { ... }
  87  * It is safe to delete the listnode using this macro.
  88  */
  89 #define ALL_LIST_ELEMENTS(list,node,nextnode,data) \
  90   (node) = listhead(list), ((data) = NULL); \
  91   (node) != NULL && \
  92     ((data) = listgetdata(node),(nextnode) = node->next, 1); \
  93   (node) = (nextnode), ((data) = NULL)
  94
  95 /* read-only list iteration macro.
  96  * Usage: as per ALL_LIST_ELEMENTS, but not safe to delete the listnode Only
  97  * use this macro when it is *immediately obvious* the listnode is not
  98  * deleted in the body of the loop. Does not have forward-reference overhead
  99  * of previous macro.
 100  */
 101 #define ALL_LIST_ELEMENTS_RO(list,node,data) \
 102   (node) = listhead(list), ((data) = NULL);\
 103   (node) != NULL && ((data) = listgetdata(node), 1); \
 104   (node) = listnextnode(node), ((data) = NULL)
 105
 106 /* these *do not* cleanup list nodes and referenced data, as the functions
 107  * do - these macros simply {de,at}tach a listnode from/to a list.
 108  */
 109
 110 /* List node attach macro.  */
 111 #define LISTNODE_ATTACH(L,N) \
 112   do { \
 113     (N)->prev = (L)->tail; \
 114     (N)->next = NULL; \
 115     if ((L)->head == NULL) \
 116       (L)->head = (N); \
 117     else \
 118       (L)->tail->next = (N); \
 119     (L)->tail = (N); \
 120     (L)->count++; \
 121   } while (0)
 122
 123 /* List node detach macro.  */
 124 #define LISTNODE_DETACH(L,N) \
 125   do { \
 126     if ((N)->prev) \
 127       (N)->prev->next = (N)->next; \
 128     else \
 129       (L)->head = (N)->next; \
 130     if ((N)->next) \
 131       (N)->next->prev = (N)->prev; \
 132     else \
 133       (L)->tail = (N)->prev; \
 134     (L)->count--; \
 135   } while (0)
 136
 137 #endif /* _ZEBRA_LINKLIST_H */