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 #include <assert.h>
  44
  45
  46 struct list_head
  47 {
  48     struct list_head *prev;
  49     struct list_head *next;
  50 };
  51
  52 static inline void list_inithead(struct list_head *item)
  53 {
  54     item->prev = item;
  55     item->next = item;
  56 }
  57
  58 static inline void list_add(struct list_head *item, struct list_head *list)
  59 {
  60     item->prev = list;
  61     item->next = list->next;
  62     list->next->prev = item;
  63     list->next = item;
  64 }
  65
  66 static inline void list_addtail(struct list_head *item, struct list_head *list)
  67 {
  68     item->next = list;
  69     item->prev = list->prev;
  70     list->prev->next = item;
  71     list->prev = item;
  72 }
  73
  74 static inline void list_replace(struct list_head *from, struct list_head *to)
  75 {
  76     to->prev = from->prev;
  77     to->next = from->next;
  78     from->next->prev = to;
  79     from->prev->next = to;
  80 }
  81
  82 static inline void list_del(struct list_head *item)
  83 {
  84     item->prev->next = item->next;
  85     item->next->prev = item->prev;
  86     item->prev = item->next = NULL;
  87 }
  88
  89 static inline void list_delinit(struct list_head *item)
  90 {
  91     item->prev->next = item->next;
  92     item->next->prev = item->prev;
  93     item->next = item;
  94     item->prev = item;
  95 }
  96
  97 static inline bool list_empty(struct list_head *list)
  98 {
  99    return list->next == list;
 100 }
 101
 102 static inline unsigned list_length(struct list_head *list)
 103 {
 104    struct list_head *node;
 105    unsigned length = 0;
 106    for (node = list->next; node != list; node = node->next)
 107       length++;
 108    return length;
 109 }
 110
 111 static inline void list_validate(struct list_head *list)
 112 {
 113    struct list_head *node;
 114    assert(list->next->prev == list && list->prev->next == list);
 115    for (node = list->next; node != list; node = node->next)
 116       assert(node->next->prev == node && node->prev->next == node);
 117 }
 118
 119 #define LIST_INITHEAD(__item) list_inithead(__item)
 120 #define LIST_ADD(__item, __list) list_add(__item, __list)
 121 #define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
 122 #define LIST_REPLACE(__from, __to) list_replace(__from, __to)
 123 #define LIST_DEL(__item) list_del(__item)
 124 #define LIST_DELINIT(__item) list_delinit(__item)
 125
 126 #define LIST_ENTRY(__type, __item, __field)   \
 127     ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
 128
 129 #define LIST_IS_EMPTY(__list)                   \
 130     ((__list)->next == (__list))
 131
 132 /**
 133  * Cast from a pointer to a member of a struct back to the containing struct.
 134  *
 135  * 'sample' MUST be initialized, or else the result is undefined!
 136  */
 137 #ifndef container_of
 138 #define container_of(ptr, sample, member)                               \
 139     (void *)((char *)(ptr)                                              \
 140              - ((char *)&(sample)->member - (char *)(sample)))
 141 #endif
 142
 143 #define list_first_entry(ptr, type, member) \
 144         LIST_ENTRY(type, (ptr)->next, member)
 145
 146 #define list_last_entry(ptr, type, member) \
 147         LIST_ENTRY(type, (ptr)->prev, member)
 148
 149
 150 #define LIST_FOR_EACH_ENTRY(pos, head, member)                          \
 151    for (pos = NULL, pos = container_of((head)->next, pos, member);      \
 152         &pos->member != (head);                                         \
 153         pos = container_of(pos->member.next, pos, member))
 154
 155 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)    \
 156    for (pos = NULL, pos = container_of((head)->next, pos, member),      \
 157         storage = container_of(pos->member.next, pos, member);  \
 158         &pos->member != (head);                                         \
 159         pos = storage, storage = container_of(storage->member.next, storage, member))
 160
 161 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)        \
 162    for (pos = NULL, pos = container_of((head)->prev, pos, member),      \
 163         storage = container_of(pos->member.prev, pos, member);          \
 164         &pos->member != (head);                                         \
 165         pos = storage, storage = container_of(storage->member.prev, storage, member))
 166
 167 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)              \
 168    for (pos = NULL, pos = container_of((start), pos, member);           \
 169         &pos->member != (head);                                         \
 170         pos = container_of(pos->member.next, pos, member))
 171
 172 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)          \
 173    for (pos = NULL, pos = container_of((start), pos, member);           \
 174         &pos->member != (head);                                         \
 175         pos = container_of(pos->member.prev, pos, member))
 176
 177 #define list_for_each_entry(type, pos, head, member)                    \
 178    for (type *pos = LIST_ENTRY(type, (head)->next, member);             \
 179         &pos->member != (head);                                         \
 180         pos = LIST_ENTRY(type, pos->member.next, member))
 181
 182 #define list_for_each_entry_safe(type, pos, head, member)               \
 183    for (type *pos = LIST_ENTRY(type, (head)->next, member),             \
 184              *__next = LIST_ENTRY(type, pos->member.next, member);      \
 185         &pos->member != (head);                                         \
 186         pos = __next,                                                   \
 187         __next = LIST_ENTRY(type, __next->member.next, member))
 188
 189 #define list_for_each_entry_rev(type, pos, head, member)                \
 190    for (type *pos = LIST_ENTRY(type, (head)->prev, member);             \
 191         &pos->member != (head);                                         \
 192         pos = LIST_ENTRY(type, pos->member.prev, member))
 193
 194 #define list_for_each_entry_safe_rev(type, pos, head, member)           \
 195    for (type *pos = LIST_ENTRY(type, (head)->prev, member),             \
 196              *__prev = LIST_ENTRY(type, pos->member.prev, member);      \
 197         &pos->member != (head);                                         \
 198         pos = __prev,                                                   \
 199         __prev = LIST_ENTRY(type, __prev->member.prev, member))
 200
 201 #define list_for_each_entry_from(type, pos, start, head, member)        \
 202    for (type *pos = LIST_ENTRY(type, (start), member);                  \
 203         &pos->member != (head);                                         \
 204         pos = LIST_ENTRY(type, pos->member.next, member))
 205
 206 #define list_for_each_entry_from_rev(type, pos, start, head, member)    \
 207    for (type *pos = LIST_ENTRY(type, (start), member);                  \
 208         &pos->member != (head);                                         \
 209         pos = LIST_ENTRY(type, pos->member.prev, member))
 210
 211 #endif /*_UTIL_LIST_H_*/