1 /* 2 ** Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved. 3 ** Distributed under the terms of the OpenBeOS License. 4 */ 5 #ifndef KERNEL_LIST_H 6 #define KERNEL_LIST_H 7 8 9 #include <SupportDefs.h> 10 11 12 /* This header defines a doubly-linked list. It differentiates between a link 13 * and an item. 14 * A link is what is put into and removed from a list, an item is the whole 15 * object that contains the link. The item doesn't have to be begin with a 16 * link; the offset to the link structure is given to init_list_etc(), so that 17 * list_get_next/prev_item() will work correctly. 18 * Note, the offset value is only needed for the *_item() functions. If the 19 * offset is 0, list_link and item are identical - if you use init_list(), 20 * you don't have to care about the difference between a link and an item. 21 */ 22 23 typedef struct list_link list_link; 24 25 /* The object that is put into the list must begin with these 26 * fields, but it doesn't have to be this structure. 27 */ 28 29 struct list_link { 30 list_link *next; 31 list_link *prev; 32 }; 33 34 struct list { 35 list_link link; 36 int32 offset; 37 }; 38 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 extern void list_init(struct list *list); 45 extern void list_init_etc(struct list *list, int32 offset); 46 extern void list_add_link_to_head(struct list *list, void *_link); 47 extern void list_add_link_to_tail(struct list *list, void *_link); 48 extern void list_remove_link(void *_link); 49 extern void *list_get_next_item(struct list *list, void *item); 50 extern void *list_get_prev_item(struct list *list, void *item); 51 extern void list_add_item(struct list *list, void *item); 52 extern void list_remove_item(struct list *list, void *item); 53 extern void *list_remove_head_item(struct list *list); 54 extern void *list_remove_tail_item(struct list *list); 55 56 static inline bool 57 list_is_empty(struct list *list) 58 { 59 return list->link.next == (list_link *)list; 60 } 61 62 static inline void * 63 list_get_first_item(struct list *list) 64 { 65 return list_get_next_item(list, NULL); 66 } 67 68 #ifdef __cplusplus 69 } 70 #endif 71 72 #endif /* KERNEL_LIST_H */ 73