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#include "c99_compat.h" 45 46#ifdef DEBUG 47# define list_assert(cond, msg) assert(cond && msg) 48#else 49# define list_assert(cond, msg) (void)(0 && (cond)) 50#endif 51 52struct list_head 53{ 54 struct list_head *prev; 55 struct list_head *next; 56}; 57 58static inline void list_inithead(struct list_head *item) 59{ 60 item->prev = item; 61 item->next = item; 62} 63 64static inline void list_add(struct list_head *item, struct list_head *list) 65{ 66 item->prev = list; 67 item->next = list->next; 68 list->next->prev = item; 69 list->next = item; 70} 71 72static inline void list_addtail(struct list_head *item, struct list_head *list) 73{ 74 item->next = list; 75 item->prev = list->prev; 76 list->prev->next = item; 77 list->prev = item; 78} 79 80static inline bool list_is_empty(const struct list_head *list); 81 82static inline void list_replace(struct list_head *from, struct list_head *to) 83{ 84 if (list_is_empty(from)) { 85 list_inithead(to); 86 } else { 87 to->prev = from->prev; 88 to->next = from->next; 89 from->next->prev = to; 90 from->prev->next = to; 91 } 92} 93 94static inline void list_del(struct list_head *item) 95{ 96 item->prev->next = item->next; 97 item->next->prev = item->prev; 98 item->prev = item->next = NULL; 99} 100 101static inline void list_delinit(struct list_head *item) 102{ 103 item->prev->next = item->next; 104 item->next->prev = item->prev; 105 item->next = item; 106 item->prev = item; 107} 108 109static inline bool list_is_empty(const struct list_head *list) 110{ 111 return list->next == list; 112} 113 114static inline bool list_is_linked(const struct list_head *list) 115{ 116 /* both must be NULL or both must be not NULL */ 117 assert((list->prev != NULL) == (list->next != NULL)); 118 119 return list->next != NULL; 120} 121 122/** 123 * Returns whether the list has exactly one element. 124 */ 125static inline bool list_is_singular(const struct list_head *list) 126{ 127 return list_is_linked(list) && !list_is_empty(list) && list->next->next == list; 128} 129 130static inline unsigned list_length(const struct list_head *list) 131{ 132 struct list_head *node; 133 unsigned length = 0; 134 for (node = list->next; node != list; node = node->next) 135 length++; 136 return length; 137} 138 139static inline void list_splice(struct list_head *src, struct list_head *dst) 140{ 141 if (list_is_empty(src)) 142 return; 143 144 src->next->prev = dst; 145 src->prev->next = dst->next; 146 dst->next->prev = src->prev; 147 dst->next = src->next; 148} 149 150static inline void list_splicetail(struct list_head *src, struct list_head *dst) 151{ 152 if (list_is_empty(src)) 153 return; 154 155 src->prev->next = dst; 156 src->next->prev = dst->prev; 157 dst->prev->next = src->next; 158 dst->prev = src->prev; 159} 160 161static inline void list_validate(const struct list_head *list) 162{ 163 struct list_head *node; 164 assert(list_is_linked(list)); 165 assert(list->next->prev == list && list->prev->next == list); 166 for (node = list->next; node != list; node = node->next) 167 assert(node->next->prev == node && node->prev->next == node); 168} 169 170#define LIST_ENTRY(__type, __item, __field) \ 171 ((__type *)(((char *)(__item)) - offsetof(__type, __field))) 172 173/** 174 * Cast from a pointer to a member of a struct back to the containing struct. 175 * 176 * 'sample' MUST be initialized, or else the result is undefined! 177 */ 178#define list_container_of(ptr, sample, member) \ 179 (void *)((char *)(ptr) \ 180 - ((char *)&(sample)->member - (char *)(sample))) 181 182#define list_first_entry(ptr, type, member) \ 183 LIST_ENTRY(type, (ptr)->next, member) 184 185#define list_last_entry(ptr, type, member) \ 186 LIST_ENTRY(type, (ptr)->prev, member) 187 188 189#define LIST_FOR_EACH_ENTRY(pos, head, member) \ 190 for (pos = NULL, pos = list_container_of((head)->next, pos, member); \ 191 &pos->member != (head); \ 192 pos = list_container_of(pos->member.next, pos, member)) 193 194#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member) \ 195 for (pos = NULL, pos = list_container_of((head)->next, pos, member), \ 196 storage = list_container_of(pos->member.next, pos, member); \ 197 &pos->member != (head); \ 198 pos = storage, storage = list_container_of(storage->member.next, storage, member)) 199 200#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member) \ 201 for (pos = NULL, pos = list_container_of((head)->prev, pos, member), \ 202 storage = list_container_of(pos->member.prev, pos, member); \ 203 &pos->member != (head); \ 204 pos = storage, storage = list_container_of(storage->member.prev, storage, member)) 205 206#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member) \ 207 for (pos = NULL, pos = list_container_of((start), pos, member); \ 208 &pos->member != (head); \ 209 pos = list_container_of(pos->member.next, pos, member)) 210 211#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member) \ 212 for (pos = NULL, pos = list_container_of((start), pos, member); \ 213 &pos->member != (head); \ 214 pos = list_container_of(pos->member.prev, pos, member)) 215 216#define list_for_each_entry(type, pos, head, member) \ 217 for (type *pos = LIST_ENTRY(type, (head)->next, member), \ 218 *__next = LIST_ENTRY(type, pos->member.next, member); \ 219 &pos->member != (head); \ 220 pos = LIST_ENTRY(type, pos->member.next, member), \ 221 list_assert(pos == __next, "use _safe iterator"), \ 222 __next = LIST_ENTRY(type, __next->member.next, member)) 223 224#define list_for_each_entry_safe(type, pos, head, member) \ 225 for (type *pos = LIST_ENTRY(type, (head)->next, member), \ 226 *__next = LIST_ENTRY(type, pos->member.next, member); \ 227 &pos->member != (head); \ 228 pos = __next, \ 229 __next = LIST_ENTRY(type, __next->member.next, member)) 230 231#define list_for_each_entry_rev(type, pos, head, member) \ 232 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \ 233 *__prev = LIST_ENTRY(type, pos->member.prev, member); \ 234 &pos->member != (head); \ 235 pos = LIST_ENTRY(type, pos->member.prev, member), \ 236 list_assert(pos == __prev, "use _safe iterator"), \ 237 __prev = LIST_ENTRY(type, __prev->member.prev, member)) 238 239#define list_for_each_entry_safe_rev(type, pos, head, member) \ 240 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \ 241 *__prev = LIST_ENTRY(type, pos->member.prev, member); \ 242 &pos->member != (head); \ 243 pos = __prev, \ 244 __prev = LIST_ENTRY(type, __prev->member.prev, member)) 245 246#define list_for_each_entry_from(type, pos, start, head, member) \ 247 for (type *pos = LIST_ENTRY(type, (start), member); \ 248 &pos->member != (head); \ 249 pos = LIST_ENTRY(type, pos->member.next, member)) 250 251#define list_for_each_entry_from_safe(type, pos, start, head, member) \ 252 for (type *pos = LIST_ENTRY(type, (start), member), \ 253 *__next = LIST_ENTRY(type, pos->member.next, member); \ 254 &pos->member != (head); \ 255 pos = __next, \ 256 __next = LIST_ENTRY(type, __next->member.next, member)) 257 258#define list_for_each_entry_from_rev(type, pos, start, head, member) \ 259 for (type *pos = LIST_ENTRY(type, (start), member); \ 260 &pos->member != (head); \ 261 pos = LIST_ENTRY(type, pos->member.prev, member)) 262 263#define list_pair_for_each_entry(type, pos1, pos2, head1, head2, member) \ 264 for (type *pos1 = LIST_ENTRY(type, (head1)->next, member), \ 265 *pos2 = LIST_ENTRY(type, (head2)->next, member); \ 266 &pos1->member != (head1) && &pos2->member != (head2); \ 267 pos1 = LIST_ENTRY(type, pos1->member.next, member), \ 268 pos2 = LIST_ENTRY(type, pos2->member.next, member)) 269 270#endif /*_UTIL_LIST_H_*/ 271