src/util/list.h

   1 /**************************************************************************
   2  *
   3  * Copyright 2006 VMware, 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
  37 #ifndef _UTIL_LIST_H_
  38 #define _UTIL_LIST_H_
  39
  40
  41 #include <stdbool.h>
  42 #include <stddef.h>
  43
  44
  45 struct list_head
  46 {
  47     struct list_head *prev;
  48     struct list_head *next;
  49 };
  50
  51 static inline void list_inithead(struct list_head *item)
  52 {
  53     item->prev = item;
  54     item->next = item;
  55 }
  56
  57 static inline void list_add(struct list_head *item, struct list_head *list)
  58 {
  59     item->prev = list;
  60     item->next = list->next;
  61     list->next->prev = item;
  62     list->next = item;
  63 }
  64
  65 static inline void list_addtail(struct list_head *item, struct list_head *list)
  66 {
  67     item->next = list;
  68     item->prev = list->prev;
  69     list->prev->next = item;
  70     list->prev = item;
  71 }
  72
  73 static inline void list_replace(struct list_head *from, struct list_head *to)
  74 {
  75     to->prev = from->prev;
  76     to->next = from->next;
  77     from->next->prev = to;
  78     from->prev->next = to;
  79 }
  80
  81 static inline void list_del(struct list_head *item)
  82 {
  83     item->prev->next = item->next;
  84     item->next->prev = item->prev;
  85     item->prev = item->next = NULL;
  86 }
  87
  88 static inline void list_delinit(struct list_head *item)
  89 {
  90     item->prev->next = item->next;
  91     item->next->prev = item->prev;
  92     item->next = item;
  93     item->prev = item;
  94 }
  95
  96 static inline bool list_empty(struct list_head *list)
  97 {
  98    return list->next == list;
  99 }
 100
 101 static inline unsigned list_length(struct list_head *list)
 102 {
 103    struct list_head *node;
 104    unsigned length = 0;
 105    for (node = list->next; node != list; node = node->next)
 106       length++;
 107    return length;
 108 }
 109
 110 #define LIST_INITHEAD(__item) list_inithead(__item)
 111 #define LIST_ADD(__item, __list) list_add(__item, __list)
 112 #define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
 113 #define LIST_REPLACE(__from, __to) list_replace(__from, __to)
 114 #define LIST_DEL(__item) list_del(__item)
 115 #define LIST_DELINIT(__item) list_delinit(__item)
 116
 117 #define LIST_ENTRY(__type, __item, __field)   \
 118     ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
 119
 120 #define LIST_IS_EMPTY(__list)                   \
 121     ((__list)->next == (__list))
 122
 123 /**
 124  * Cast from a pointer to a member of a struct back to the containing struct.
 125  *
 126  * 'sample' MUST be initialized, or else the result is undefined!
 127  */
 128 #ifndef container_of
 129 #define container_of(ptr, sample, member)                               \
 130     (void *)((char *)(ptr)                                              \
 131              - ((char *)&(sample)->member - (char *)(sample)))
 132 #endif
 133
 134 #define LIST_FOR_EACH_ENTRY(pos, head, member)                          \
 135    for (pos = NULL, pos = container_of((head)->next, pos, member);      \
 136         &pos->member != (head);                                         \
 137         pos = container_of(pos->member.next, pos, member))
 138
 139 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)    \
 140    for (pos = NULL, pos = container_of((head)->next, pos, member),      \
 141         storage = container_of(pos->member.next, pos, member);  \
 142         &pos->member != (head);                                         \
 143         pos = storage, storage = container_of(storage->member.next, storage, member))
 144
 145 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)        \
 146    for (pos = NULL, pos = container_of((head)->prev, pos, member),      \
 147         storage = container_of(pos->member.prev, pos, member);          \
 148         &pos->member != (head);                                         \
 149         pos = storage, storage = container_of(storage->member.prev, storage, member))
 150
 151 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)              \
 152    for (pos = NULL, pos = container_of((start), pos, member);           \
 153         &pos->member != (head);                                         \
 154         pos = container_of(pos->member.next, pos, member))
 155
 156 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)          \
 157    for (pos = NULL, pos = container_of((start), pos, member);           \
 158         &pos->member != (head);                                         \
 159         pos = container_of(pos->member.prev, pos, member))
 160
 161 #define list_for_each_entry(type, pos, head, member)                    \
 162    for (type *pos = LIST_ENTRY(type, (head)->next, member);             \
 163         &pos->member != (head);                                         \
 164         pos = LIST_ENTRY(type, pos->member.next, member))
 165
 166 #define list_for_each_entry_safe(type, pos, head, member)               \
 167    for (type *pos = LIST_ENTRY(type, (head)->next, member),             \
 168              *__next = LIST_ENTRY(type, pos->member.next, member);      \
 169         &pos->member != (head);                                         \
 170         pos = __next,                                                   \
 171         __next = LIST_ENTRY(type, __next->member.next, member))
 172
 173 #define list_for_each_entry_rev(type, pos, head, member)                \
 174    for (type *pos = LIST_ENTRY(type, (head)->prev, member);             \
 175         &pos->member != (head);                                         \
 176         pos = LIST_ENTRY(type, pos->member.prev, member))
 177
 178 #define list_for_each_entry_safe_rev(type, pos, head, member)           \
 179    for (type *pos = LIST_ENTRY(type, (head)->prev, member),             \
 180              *__prev = LIST_ENTRY(type, pos->member.prev, member);      \
 181         &pos->member != (head);                                         \
 182         pos = __prev,                                                   \
 183         __prev = LIST_ENTRY(type, __prev->member.prev, member))
 184
 185 #define list_for_each_entry_from(type, pos, start, head, member)        \
 186    for (type *pos = LIST_ENTRY(type, (start), member);                  \
 187         &pos->member != (head);                                         \
 188         pos = LIST_ENTRY(type, pos->member.next, member))
 189
 190 #define list_for_each_entry_from_rev(type, pos, start, head, member)    \
 191    for (type *pos = LIST_ENTRY(type, (start), member);                  \
 192         &pos->member != (head);                                         \
 193         pos = LIST_ENTRY(type, pos->member.prev, member))
 194
 195 #endif /*_UTIL_LIST_H_*/