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#define list_assert(cond, msg) assert(cond && msg) 46 47struct list_head 48{ 49 struct list_head *prev; 50 struct list_head *next; 51}; 52 53static inline void list_inithead(struct list_head *item) 54{ 55 item->prev = item; 56 item->next = item; 57} 58 59/** 60 * Prepend an item to a list 61 * 62 * @param item The element to add to the list 63 * @param list The list to prepend to 64 */ 65static inline void list_add(struct list_head *item, struct list_head *list) 66{ 67 item->prev = list; 68 item->next = list->next; 69 list->next->prev = item; 70 list->next = item; 71} 72 73/** 74 * Append an item to a list 75 * 76 * @param item The element to add to the list 77 * @param list The list to append to 78 */ 79static inline void list_addtail(struct list_head *item, struct list_head *list) 80{ 81 item->next = list; 82 item->prev = list->prev; 83 list->prev->next = item; 84 list->prev = item; 85} 86 87static inline bool list_is_empty(const struct list_head *list); 88 89static inline void list_replace(struct list_head *from, struct list_head *to) 90{ 91 if (list_is_empty(from)) { 92 list_inithead(to); 93 } else { 94 to->prev = from->prev; 95 to->next = from->next; 96 from->next->prev = to; 97 from->prev->next = to; 98 } 99} 100 101static inline void list_del(struct list_head *item) 102{ 103 item->prev->next = item->next; 104 item->next->prev = item->prev; 105 item->prev = item->next = NULL; 106} 107 108static inline void list_delinit(struct list_head *item) 109{ 110 item->prev->next = item->next; 111 item->next->prev = item->prev; 112 item->next = item; 113 item->prev = item; 114} 115 116static inline bool list_is_empty(const struct list_head *list) 117{ 118 return list->next == list; 119} 120 121static inline bool list_is_linked(const struct list_head *list) 122{ 123 /* both must be NULL or both must be not NULL */ 124 assert((list->prev != NULL) == (list->next != NULL)); 125 126 return list->next != NULL; 127} 128 129/** 130 * Returns whether the list has exactly one element. 131 */ 132static inline bool list_is_singular(const struct list_head *list) 133{ 134 return list_is_linked(list) && !list_is_empty(list) && list->next->next == list; 135} 136 137static inline unsigned list_length(const struct list_head *list) 138{ 139 struct list_head *node; 140 unsigned length = 0; 141 for (node = list->next; node != list; node = node->next) 142 length++; 143 return length; 144} 145 146static inline void list_splice(struct list_head *src, struct list_head *dst) 147{ 148 if (list_is_empty(src)) 149 return; 150 151 src->next->prev = dst; 152 src->prev->next = dst->next; 153 dst->next->prev = src->prev; 154 dst->next = src->next; 155} 156 157static inline void list_splicetail(struct list_head *src, struct list_head *dst) 158{ 159 if (list_is_empty(src)) 160 return; 161 162 src->prev->next = dst; 163 src->next->prev = dst->prev; 164 dst->prev->next = src->next; 165 dst->prev = src->prev; 166} 167 168static inline void list_validate(const struct list_head *list) 169{ 170 struct list_head *node; 171 assert(list_is_linked(list)); 172 assert(list->next->prev == list && list->prev->next == list); 173 for (node = list->next; node != list; node = node->next) 174 assert(node->next->prev == node && node->prev->next == node); 175} 176 177/** 178 * Move an item from one place in a list to another 179 * 180 * The item can be in this list, or in another. 181 * 182 * @param item The item to move 183 * @param loc The element to put the item in front of 184 */ 185static inline void list_move_to(struct list_head *item, struct list_head *loc) { 186 list_del(item); 187 list_add(item, loc); 188} 189 190#define list_entry(__item, __type, __field) \ 191 ((__type *)(((char *)(__item)) - offsetof(__type, __field))) 192 193/** 194 * Cast from a pointer to a member of a struct back to the containing struct. 195 * 196 * 'sample' MUST be initialized, or else the result is undefined! 197 */ 198#define list_container_of(ptr, sample, member) \ 199 (void *)((char *)(ptr) \ 200 - ((char *)&(sample)->member - (char *)(sample))) 201 202#define list_first_entry(ptr, type, member) \ 203 list_entry((ptr)->next, type, member) 204 205#define list_last_entry(ptr, type, member) \ 206 list_entry((ptr)->prev, type, member) 207 208 209#define LIST_FOR_EACH_ENTRY(pos, head, member) \ 210 for (pos = NULL, pos = list_container_of((head)->next, pos, member); \ 211 &pos->member != (head); \ 212 pos = list_container_of(pos->member.next, pos, member)) 213 214#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member) \ 215 for (pos = NULL, pos = list_container_of((head)->next, pos, member), \ 216 storage = list_container_of(pos->member.next, pos, member); \ 217 &pos->member != (head); \ 218 pos = storage, storage = list_container_of(storage->member.next, storage, member)) 219 220#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member) \ 221 for (pos = NULL, pos = list_container_of((head)->prev, pos, member), \ 222 storage = list_container_of(pos->member.prev, pos, member); \ 223 &pos->member != (head); \ 224 pos = storage, storage = list_container_of(storage->member.prev, storage, member)) 225 226#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member) \ 227 for (pos = NULL, pos = list_container_of((start), pos, member); \ 228 &pos->member != (head); \ 229 pos = list_container_of(pos->member.next, pos, member)) 230 231#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member) \ 232 for (pos = NULL, pos = list_container_of((start), pos, member); \ 233 &pos->member != (head); \ 234 pos = list_container_of(pos->member.prev, pos, member)) 235 236#define list_for_each_entry(type, pos, head, member) \ 237 for (type *pos = list_entry((head)->next, type, member), \ 238 *__next = list_entry(pos->member.next, type, member); \ 239 &pos->member != (head); \ 240 pos = list_entry(pos->member.next, type, member), \ 241 list_assert(pos == __next, "use _safe iterator"), \ 242 __next = list_entry(__next->member.next, type, member)) 243 244#define list_for_each_entry_safe(type, pos, head, member) \ 245 for (type *pos = list_entry((head)->next, type, member), \ 246 *__next = list_entry(pos->member.next, type, member); \ 247 &pos->member != (head); \ 248 pos = __next, \ 249 __next = list_entry(__next->member.next, type, member)) 250 251#define list_for_each_entry_rev(type, pos, head, member) \ 252 for (type *pos = list_entry((head)->prev, type, member), \ 253 *__prev = list_entry(pos->member.prev, type, member); \ 254 &pos->member != (head); \ 255 pos = list_entry(pos->member.prev, type, member), \ 256 list_assert(pos == __prev, "use _safe iterator"), \ 257 __prev = list_entry(__prev->member.prev, type, member)) 258 259#define list_for_each_entry_safe_rev(type, pos, head, member) \ 260 for (type *pos = list_entry((head)->prev, type, member), \ 261 *__prev = list_entry(pos->member.prev, type, member); \ 262 &pos->member != (head); \ 263 pos = __prev, \ 264 __prev = list_entry(__prev->member.prev, type, member)) 265 266#define list_for_each_entry_from(type, pos, start, head, member) \ 267 for (type *pos = list_entry((start), type, member); \ 268 &pos->member != (head); \ 269 pos = list_entry(pos->member.next, type, member)) 270 271#define list_for_each_entry_from_safe(type, pos, start, head, member) \ 272 for (type *pos = list_entry((start), type, member), \ 273 *__next = list_entry(pos->member.next, type, member); \ 274 &pos->member != (head); \ 275 pos = __next, \ 276 __next = list_entry(__next->member.next, type, member)) 277 278#define list_for_each_entry_from_rev(type, pos, start, head, member) \ 279 for (type *pos = list_entry((start), type, member); \ 280 &pos->member != (head); \ 281 pos = list_entry(pos->member.prev, type, member)) 282 283#define list_pair_for_each_entry(type, pos1, pos2, head1, head2, member) \ 284 for (type *pos1 = list_entry((head1)->next, type, member), \ 285 *pos2 = list_entry((head2)->next, type, member); \ 286 &pos1->member != (head1) && &pos2->member != (head2); \ 287 pos1 = list_entry(pos1->member.next, type, member), \ 288 pos2 = list_entry(pos2->member.next, type, member)) 289 290#endif /*_UTIL_LIST_H_*/ 291