1 /* 2 * libkmod - interface to kernel module operations 3 * 4 * Copyright (C) 2011-2013 ProFUSION embedded systems 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <stdlib.h> 21 22 #include "libkmod.h" 23 #include "libkmod-internal.h" 24 25 /** 26 * SECTION:libkmod-list 27 * @short_description: general purpose list 28 */ 29 30 static inline struct list_node *list_node_init(struct list_node *node) 31 { 32 node->next = node; 33 node->prev = node; 34 35 return node; 36 } 37 38 static inline void list_node_append(struct list_node *list, 39 struct list_node *node) 40 { 41 if (list == NULL) { 42 list_node_init(node); 43 return; 44 } 45 46 node->prev = list->prev; 47 list->prev->next = node; 48 list->prev = node; 49 node->next = list; 50 } 51 52 static inline struct list_node *list_node_remove(struct list_node *node) 53 { 54 if (node->prev == node || node->next == node) 55 return NULL; 56 57 node->prev->next = node->next; 58 node->next->prev = node->prev; 59 60 return node->next; 61 } 62 63 static inline void list_node_insert_after(struct list_node *list, 64 struct list_node *node) 65 { 66 if (list == NULL) { 67 list_node_init(node); 68 return; 69 } 70 71 node->prev = list; 72 node->next = list->next; 73 list->next->prev = node; 74 list->next = node; 75 } 76 77 static inline void list_node_insert_before(struct list_node *list, 78 struct list_node *node) 79 { 80 if (list == NULL) { 81 list_node_init(node); 82 return; 83 } 84 85 node->next = list; 86 node->prev = list->prev; 87 list->prev->next = node; 88 list->prev = node; 89 } 90 91 static inline void list_node_append_list(struct list_node *list1, 92 struct list_node *list2) 93 { 94 struct list_node *list1_last; 95 96 if (list1 == NULL) { 97 list_node_init(list2); 98 return; 99 } 100 101 list1->prev->next = list2; 102 list2->prev->next = list1; 103 104 /* cache the last, because we will lose the pointer */ 105 list1_last = list1->prev; 106 107 list1->prev = list2->prev; 108 list2->prev = list1_last; 109 } 110 111 struct kmod_list *kmod_list_append(struct kmod_list *list, const void *data) 112 { 113 struct kmod_list *new; 114 115 new = malloc(sizeof(*new)); 116 if (new == NULL) 117 return NULL; 118 119 new->data = (void *)data; 120 list_node_append(list ? &list->node : NULL, &new->node); 121 122 return list ? list : new; 123 } 124 125 struct kmod_list *kmod_list_insert_after(struct kmod_list *list, 126 const void *data) 127 { 128 struct kmod_list *new; 129 130 if (list == NULL) 131 return kmod_list_append(list, data); 132 133 new = malloc(sizeof(*new)); 134 if (new == NULL) 135 return NULL; 136 137 new->data = (void *)data; 138 list_node_insert_after(&list->node, &new->node); 139 140 return list; 141 } 142 143 struct kmod_list *kmod_list_insert_before(struct kmod_list *list, 144 const void *data) 145 { 146 struct kmod_list *new; 147 148 if (list == NULL) 149 return kmod_list_append(list, data); 150 151 new = malloc(sizeof(*new)); 152 if (new == NULL) 153 return NULL; 154 155 new->data = (void *)data; 156 list_node_insert_before(&list->node, &new->node); 157 158 return new; 159 } 160 161 struct kmod_list *kmod_list_append_list(struct kmod_list *list1, 162 struct kmod_list *list2) 163 { 164 if (list1 == NULL) 165 return list2; 166 167 if (list2 == NULL) 168 return list1; 169 170 list_node_append_list(&list1->node, &list2->node); 171 172 return list1; 173 } 174 175 struct kmod_list *kmod_list_prepend(struct kmod_list *list, const void *data) 176 { 177 struct kmod_list *new; 178 179 new = malloc(sizeof(*new)); 180 if (new == NULL) 181 return NULL; 182 183 new->data = (void *)data; 184 list_node_append(list ? &list->node : NULL, &new->node); 185 186 return new; 187 } 188 189 struct kmod_list *kmod_list_remove(struct kmod_list *list) 190 { 191 struct list_node *node; 192 193 if (list == NULL) 194 return NULL; 195 196 node = list_node_remove(&list->node); 197 free(list); 198 199 if (node == NULL) 200 return NULL; 201 202 return container_of(node, struct kmod_list, node); 203 } 204 205 struct kmod_list *kmod_list_remove_data(struct kmod_list *list, 206 const void *data) 207 { 208 struct kmod_list *itr; 209 struct list_node *node; 210 211 for (itr = list; itr != NULL; itr = kmod_list_next(list, itr)) { 212 if (itr->data == data) 213 break; 214 } 215 216 if (itr == NULL) 217 return list; 218 219 node = list_node_remove(&itr->node); 220 free(itr); 221 222 if (node == NULL) 223 return NULL; 224 225 return container_of(node, struct kmod_list, node); 226 } 227 228 /* 229 * n must be greater to or equal the number of elements (we don't check the 230 * condition) 231 */ 232 struct kmod_list *kmod_list_remove_n_latest(struct kmod_list *list, 233 unsigned int n) 234 { 235 struct kmod_list *l = list; 236 unsigned int i; 237 238 for (i = 0; i < n; i++) { 239 l = kmod_list_last(l); 240 l = kmod_list_remove(l); 241 } 242 243 return l; 244 } 245 246 /** 247 * kmod_list_prev: 248 * @list: the head of the list 249 * @curr: the current node in the list 250 * 251 * Get the previous node in @list relative to @curr as if @list was not a 252 * circular list. I.e.: the previous of the head is NULL. It can be used to 253 * iterate a list by checking for NULL return to know when all elements were 254 * iterated. 255 * 256 * Returns: node previous to @curr or NULL if either this node is the head of 257 * the list or the list is empty. 258 */ 259 KMOD_EXPORT struct kmod_list *kmod_list_prev(const struct kmod_list *list, 260 const struct kmod_list *curr) 261 { 262 if (list == NULL || curr == NULL) 263 return NULL; 264 265 if (list == curr) 266 return NULL; 267 268 return container_of(curr->node.prev, struct kmod_list, node); 269 } 270 271 /** 272 * kmod_list_next: 273 * @list: the head of the list 274 * @curr: the current node in the list 275 * 276 * Get the next node in @list relative to @curr as if @list was not a circular 277 * list. I.e. calling this function in the last node of the list returns 278 * NULL.. It can be used to iterate a list by checking for NULL return to know 279 * when all elements were iterated. 280 * 281 * Returns: node next to @curr or NULL if either this node is the last of or 282 * list is empty. 283 */ 284 KMOD_EXPORT struct kmod_list *kmod_list_next(const struct kmod_list *list, 285 const struct kmod_list *curr) 286 { 287 if (list == NULL || curr == NULL) 288 return NULL; 289 290 if (curr->node.next == &list->node) 291 return NULL; 292 293 return container_of(curr->node.next, struct kmod_list, node); 294 } 295 296 /** 297 * kmod_list_last: 298 * @list: the head of the list 299 * 300 * Get the last element of the @list. As @list is a circular list, 301 * this is a cheap operation O(1) with the last element being the 302 * previous element. 303 * 304 * If the list has a single element it will return the list itself (as 305 * expected, and this is what differentiates from kmod_list_prev()). 306 * 307 * Returns: last node at @list or NULL if the list is empty. 308 */ 309 KMOD_EXPORT struct kmod_list *kmod_list_last(const struct kmod_list *list) 310 { 311 if (list == NULL) 312 return NULL; 313 return container_of(list->node.prev, struct kmod_list, node); 314 } 315
