reactos/include/wine/list.h

   1 /*
   2  * Linked lists support
   3  *
   4  * Copyright (C) 2002 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #ifndef __WINE_SERVER_LIST_H
  22 #define __WINE_SERVER_LIST_H
  23
  24 struct list
  25 {
  26     struct list *next;
  27     struct list *prev;
  28 };
  29
  30 /* Define a list like so:
  31  *
  32  *   struct gadget
  33  *   {
  34  *       struct list  entry;   <-- doesn't have to be the first item in the struct
  35  *       int          a, b;
  36  *   };
  37  *
  38  *   static struct list global_gadgets = LIST_INIT( global_gadgets );
  39  *
  40  * or
  41  *
  42  *   struct some_global_thing
  43  *   {
  44  *       struct list gadgets;
  45  *   };
  46  *
  47  *   list_init( &some_global_thing->gadgets );
  48  *
  49  * Manipulate it like this:
  50  *
  51  *   list_add_head( &global_gadgets, &new_gadget->entry );
  52  *   list_remove( &new_gadget->entry );
  53  *   list_add_after( &some_random_gadget->entry, &new_gadget->entry );
  54  *
  55  * And to iterate over it:
  56  *
  57  *   struct list *cursor;
  58  *   LIST_FOR_EACH( cursor, &global_gadgets )
  59  *   {
  60  *       struct gadget *gadget = LIST_ENTRY( cursor, struct gadget, entry );
  61  *   }
  62  *
  63  */
  64
  65 /* add an element after the specified one */
  66 inline static void list_add_after( struct list *elem, struct list *to_add )
  67 {
  68     to_add->next = elem->next;
  69     to_add->prev = elem;
  70     elem->next->prev = to_add;
  71     elem->next = to_add;
  72 }
  73
  74 /* add an element before the specified one */
  75 inline static void list_add_before( struct list *elem, struct list *to_add )
  76 {
  77     to_add->next = elem;
  78     to_add->prev = elem->prev;
  79     elem->prev->next = to_add;
  80     elem->prev = to_add;
  81 }
  82
  83 /* add element at the head of the list */
  84 inline static void list_add_head( struct list *list, struct list *elem )
  85 {
  86     list_add_after( list, elem );
  87 }
  88
  89 /* add element at the tail of the list */
  90 inline static void list_add_tail( struct list *list, struct list *elem )
  91 {
  92     list_add_before( list, elem );
  93 }
  94
  95 /* remove an element from its list */
  96 inline static void list_remove( struct list *elem )
  97 {
  98     elem->next->prev = elem->prev;
  99     elem->prev->next = elem->next;
 100 }
 101
 102 /* get the next element */
 103 inline static struct list *list_next( struct list *list, struct list *elem )
 104 {
 105     struct list *ret = elem->next;
 106     if (elem->next == list) ret = NULL;
 107     return ret;
 108 }
 109
 110 /* get the previous element */
 111 inline static struct list *list_prev( struct list *list, struct list *elem )
 112 {
 113     struct list *ret = elem->prev;
 114     if (elem->prev == list) ret = NULL;
 115     return ret;
 116 }
 117
 118 /* get the first element */
 119 inline static struct list *list_head( struct list *list )
 120 {
 121     return list_next( list, list );
 122 }
 123
 124 /* get the last element */
 125 inline static struct list *list_tail( struct list *list )
 126 {
 127     return list_prev( list, list );
 128 }
 129
 130 /* check if a list is empty */
 131 inline static int list_empty( struct list *list )
 132 {
 133     return list->next == list;
 134 }
 135
 136 /* initialize a list */
 137 inline static void list_init( struct list *list )
 138 {
 139     list->next = list->prev = list;
 140 }
 141
 142 /* iterate through the list */
 143 #define LIST_FOR_EACH(cursor,list) \
 144     for ((cursor) = (list)->next; (cursor) != (list); (cursor) = (cursor)->next)
 145
 146 /* macros for statically initialized lists */
 147 #define LIST_INIT(list)  { &(list), &(list) }
 148
 149 /* get pointer to object containing list element */
 150 #define LIST_ENTRY(elem, type, field) \
 151     ((type *)((char *)(elem) - (unsigned int)(&((type *)0)->field)))
 152
 153 #endif  /* __WINE_SERVER_LIST_H */