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