util_double_list.h

   1 /*
   2  *
   3  * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  18  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  19  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  20  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * The above copyright notice and this permission notice (including the
  23  * next paragraph) shall be included in all copies or substantial portions
  24  * of the Software.
  25  *
  26  */
  27
  28 /**
  29  * \file
  30  * List macros heavily inspired by the Linux kernel
  31  * list handling. No list looping yet.
  32  *
  33  * Is not threadsafe, so common operations need to
  34  * be protected using an external mutex.
  35  */
  36 #ifndef _U_DOUBLE_LIST_H_
  37 #define _U_DOUBLE_LIST_H_
  38
  39 #include <stddef.h>
  40
  41 struct list_head
  42 {
  43     struct list_head *prev;
  44     struct list_head *next;
  45 };
  46
  47 static inline void list_inithead(struct list_head *item)
  48 {
  49     item->prev = item;
  50     item->next = item;
  51 }
  52
  53 static inline void list_add(struct list_head *item, struct list_head *list)
  54 {
  55     item->prev = list;
  56     item->next = list->next;
  57     list->next->prev = item;
  58     list->next = item;
  59 }
  60
  61 static inline void list_addtail(struct list_head *item, struct list_head *list)
  62 {
  63     item->next = list;
  64     item->prev = list->prev;
  65     list->prev->next = item;
  66     list->prev = item;
  67 }
  68
  69 static inline void list_replace(struct list_head *from, struct list_head *to)
  70 {
  71     to->prev = from->prev;
  72     to->next = from->next;
  73     from->next->prev = to;
  74     from->prev->next = to;
  75 }
  76
  77 static inline void list_del(struct list_head *item)
  78 {
  79     item->prev->next = item->next;
  80     item->next->prev = item->prev;
  81 }
  82
  83 static inline void list_delinit(struct list_head *item)
  84 {
  85     item->prev->next = item->next;
  86     item->next->prev = item->prev;
  87     item->next = item;
  88     item->prev = item;
  89 }
  90
  91 #define LIST_INITHEAD(__item) list_inithead(__item)
  92 #define LIST_ADD(__item, __list) list_add(__item, __list)
  93 #define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
  94 #define LIST_REPLACE(__from, __to) list_replace(__from, __to)
  95 #define LIST_DEL(__item) list_del(__item)
  96 #define LIST_DELINIT(__item) list_delinit(__item)
  97
  98 #define LIST_ENTRY(__type, __item, __field)   \
  99     ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
 100
 101 #define LIST_FIRST_ENTRY(__ptr, __type, __field)   \
 102     LIST_ENTRY(__type, (__ptr)->next, __field)
 103
 104 #define LIST_LAST_ENTRY(__ptr, __type, __field)   \
 105     LIST_ENTRY(__type, (__ptr)->prev, __field)
 106
 107 #define LIST_IS_EMPTY(__list)                   \
 108     ((__list)->next == (__list))
 109
 110 #ifndef container_of
 111 #define container_of(ptr, sample, member)                               \
 112     (void *)((char *)(ptr)                                              \
 113              - ((char *)&((typeof(sample))0)->member))
 114 #endif
 115
 116 #define LIST_FOR_EACH_ENTRY(pos, head, member)                          \
 117    for (pos = container_of((head)->next, pos, member);                  \
 118         &pos->member != (head);                                         \
 119         pos = container_of(pos->member.next, pos, member))
 120
 121 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)    \
 122    for (pos = container_of((head)->next, pos, member),                  \
 123         storage = container_of(pos->member.next, pos, member);  \
 124         &pos->member != (head);                                         \
 125         pos = storage, storage = container_of(storage->member.next, storage, member))
 126
 127 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)        \
 128    for (pos = container_of((head)->prev, pos, member),                  \
 129         storage = container_of(pos->member.prev, pos, member);          \
 130         &pos->member != (head);                                         \
 131         pos = storage, storage = container_of(storage->member.prev, storage, member))
 132
 133 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)              \
 134    for (pos = container_of((start), pos, member);                       \
 135         &pos->member != (head);                                         \
 136         pos = container_of(pos->member.next, pos, member))
 137
 138 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)          \
 139    for (pos = container_of((start), pos, member);                       \
 140         &pos->member != (head);                                         \
 141         pos = container_of(pos->member.prev, pos, member))
 142
 143 #endif /*_U_DOUBLE_LIST_H_*/