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 bool list_empty(struct list_head *list); 75 76 static inline void list_replace(struct list_head *from, struct list_head *to) 77 { 78 if (list_empty(from)) { 79 list_inithead(to); 80 } else { 81 to->prev = from->prev; 82 to->next = from->next; 83 from->next->prev = to; 84 from->prev->next = to; 85 } 86 } 87 88 static inline void list_del(struct list_head *item) 89 { 90 item->prev->next = item->next; 91 item->next->prev = item->prev; 92 item->prev = item->next = NULL; 93 } 94 95 static inline void list_delinit(struct list_head *item) 96 { 97 item->prev->next = item->next; 98 item->next->prev = item->prev; 99 item->next = item; 100 item->prev = item; 101 } 102 103 static inline bool list_empty(struct list_head *list) 104 { 105 return list->next == list; 106 } 107 108 /** 109 * Returns whether the list has exactly one element. 110 */ 111 static inline bool list_is_singular(const struct list_head *list) 112 { 113 return list->next != NULL && list->next != list && list->next->next == list; 114 } 115 116 static inline unsigned list_length(struct list_head *list) 117 { 118 struct list_head *node; 119 unsigned length = 0; 120 for (node = list->next; node != list; node = node->next) 121 length++; 122 return length; 123 } 124 125 static inline void list_splice(struct list_head *src, struct list_head *dst) 126 { 127 if (list_empty(src)) 128 return; 129 130 src->next->prev = dst; 131 src->prev->next = dst->next; 132 dst->next->prev = src->prev; 133 dst->next = src->next; 134 } 135 136 static inline void list_splicetail(struct list_head *src, struct list_head *dst) 137 { 138 if (list_empty(src)) 139 return; 140 141 src->prev->next = dst; 142 src->next->prev = dst->prev; 143 dst->prev->next = src->next; 144 dst->prev = src->prev; 145 } 146 147 static inline void list_validate(struct list_head *list) 148 { 149 struct list_head *node; 150 assert(list->next->prev == list && list->prev->next == list); 151 for (node = list->next; node != list; node = node->next) 152 assert(node->next->prev == node && node->prev->next == node); 153 } 154 155 #define LIST_INITHEAD(__item) list_inithead(__item) 156 #define LIST_ADD(__item, __list) list_add(__item, __list) 157 #define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list) 158 #define LIST_REPLACE(__from, __to) list_replace(__from, __to) 159 #define LIST_DEL(__item) list_del(__item) 160 #define LIST_DELINIT(__item) list_delinit(__item) 161 162 #define LIST_ENTRY(__type, __item, __field) \ 163 ((__type *)(((char *)(__item)) - offsetof(__type, __field))) 164 165 #define LIST_IS_EMPTY(__list) \ 166 ((__list)->next == (__list)) 167 168 /** 169 * Cast from a pointer to a member of a struct back to the containing struct. 170 * 171 * 'sample' MUST be initialized, or else the result is undefined! 172 */ 173 #ifndef container_of 174 #define container_of(ptr, sample, member) \ 175 (void *)((char *)(ptr) \ 176 - ((char *)&(sample)->member - (char *)(sample))) 177 #endif 178 179 #define list_first_entry(ptr, type, member) \ 180 LIST_ENTRY(type, (ptr)->next, member) 181 182 #define list_last_entry(ptr, type, member) \ 183 LIST_ENTRY(type, (ptr)->prev, member) 184 185 186 #define LIST_FOR_EACH_ENTRY(pos, head, member) \ 187 for (pos = NULL, pos = container_of((head)->next, pos, member); \ 188 &pos->member != (head); \ 189 pos = container_of(pos->member.next, pos, member)) 190 191 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member) \ 192 for (pos = NULL, pos = container_of((head)->next, pos, member), \ 193 storage = container_of(pos->member.next, pos, member); \ 194 &pos->member != (head); \ 195 pos = storage, storage = container_of(storage->member.next, storage, member)) 196 197 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member) \ 198 for (pos = NULL, pos = container_of((head)->prev, pos, member), \ 199 storage = container_of(pos->member.prev, pos, member); \ 200 &pos->member != (head); \ 201 pos = storage, storage = container_of(storage->member.prev, storage, member)) 202 203 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member) \ 204 for (pos = NULL, pos = container_of((start), pos, member); \ 205 &pos->member != (head); \ 206 pos = container_of(pos->member.next, pos, member)) 207 208 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member) \ 209 for (pos = NULL, pos = container_of((start), pos, member); \ 210 &pos->member != (head); \ 211 pos = container_of(pos->member.prev, pos, member)) 212 213 #define list_for_each_entry(type, pos, head, member) \ 214 for (type *pos = LIST_ENTRY(type, (head)->next, member); \ 215 &pos->member != (head); \ 216 pos = LIST_ENTRY(type, pos->member.next, member)) 217 218 #define list_for_each_entry_safe(type, pos, head, member) \ 219 for (type *pos = LIST_ENTRY(type, (head)->next, member), \ 220 *__next = LIST_ENTRY(type, pos->member.next, member); \ 221 &pos->member != (head); \ 222 pos = __next, \ 223 __next = LIST_ENTRY(type, __next->member.next, member)) 224 225 #define list_for_each_entry_rev(type, pos, head, member) \ 226 for (type *pos = LIST_ENTRY(type, (head)->prev, member); \ 227 &pos->member != (head); \ 228 pos = LIST_ENTRY(type, pos->member.prev, member)) 229 230 #define list_for_each_entry_safe_rev(type, pos, head, member) \ 231 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \ 232 *__prev = LIST_ENTRY(type, pos->member.prev, member); \ 233 &pos->member != (head); \ 234 pos = __prev, \ 235 __prev = LIST_ENTRY(type, __prev->member.prev, member)) 236 237 #define list_for_each_entry_from(type, pos, start, head, member) \ 238 for (type *pos = LIST_ENTRY(type, (start), member); \ 239 &pos->member != (head); \ 240 pos = LIST_ENTRY(type, pos->member.next, member)) 241 242 #define list_for_each_entry_from_rev(type, pos, start, head, member) \ 243 for (type *pos = LIST_ENTRY(type, (start), member); \ 244 &pos->member != (head); \ 245 pos = LIST_ENTRY(type, pos->member.prev, member)) 246 247 #endif /*_UTIL_LIST_H_*/ 248
