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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef _LIST_H_
     18 #define _LIST_H_
     19 
     20 #include <stdbool.h>
     21 
     22 struct link_t
     23 {
     24     struct link_t *prev, *next;
     25 } typedef link_t;
     26 
     27 #define list_iterate(list, cur_link, tmp_link)                  \
     28     for ((cur_link) = (list)->next,                             \
     29             (tmp_link) = (cur_link) ? (cur_link)->next : NULL;  \
     30          (cur_link) != NULL && (cur_link) != (list);            \
     31          (cur_link) = (tmp_link), (tmp_link) = (cur_link)->next)
     32 
     33 #define DECLARE_LIST(list) \
     34     link_t list = { .prev = &list, .next = &list }
     35 
     36 static inline void list_init(struct link_t *list)
     37 {
     38     list->prev = list->next = list;
     39 }
     40 
     41 static inline void list_add_tail(struct link_t *list, struct link_t *item)
     42 {
     43     if (!list->next)
     44         list_init(list);
     45 
     46     item->prev = list->prev;
     47     item->next = list;
     48     list->prev->next = item;
     49     list->prev = item;
     50 }
     51 
     52 static inline void list_delete(struct link_t *item)
     53 {
     54     item->prev->next = item->next;
     55     item->next->prev = item->prev;
     56     item->next = item->prev = item;
     57 }
     58 
     59 static inline bool list_is_empty(struct link_t *list)
     60 {
     61     return !list->next || list->next == list;
     62 }
     63 
     64 #endif
     65 
     66