80 lines
2 KiB
C
80 lines
2 KiB
C
/* Linux-style linked list implementation */
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#ifndef __LIST_H__
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#define __LIST_H__
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#include <stddef.h> /* for offsetof() macro */
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struct list_head {
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struct list_head *next;
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struct list_head *prev;
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};
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/* Declare an empty list */
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#define LIST_HEAD(x) struct list_head x = { &x, &x }
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/* Initialize an empty list (required for all malloc'd list_heads) */
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static inline void INIT_LIST_HEAD(struct list_head *x)
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{
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x->next = x;
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x->prev = x;
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}
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/* Remove an entry from its current list (if any) and insert it into the
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* beginning of the given list */
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static inline void list_add(struct list_head *x, struct list_head *head)
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{
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x->next->prev = x->prev;
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x->prev->next = x->next;
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x->next = head->next;
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x->prev = head;
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head->next = x;
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x->next->prev = x;
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}
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/* Remove an entry from its current list (if any) and insert it into the
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* end of the given list */
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static inline void list_add_tail(struct list_head *x, struct list_head *head)
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{
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x->next->prev = x->prev;
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x->prev->next = x->next;
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x->prev = head->prev;
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x->next = head;
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head->prev = x;
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x->prev->next = x;
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}
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/* Remove an entry from its current list and reinitialize it */
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static inline void list_del(struct list_head *x)
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{
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x->next->prev = x->prev;
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x->prev->next = x->next;
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x->next = x;
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x->prev = x;
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}
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#define list_del_init list_del
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#define list_move list_add
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#define list_move_tail list_add_tail
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/* Test if list is empty (contains no other entries) */
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static inline int list_empty(const struct list_head *x)
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{
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return x->next == x;
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}
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/* Get a pointer to the object containing x, which is of type "type" and
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* embeds x as a field called "field" */
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#define list_entry(x, type, field) ({ \
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const typeof( ((type *)0)->field ) *__mptr = (x); \
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(type *)( (char *)__mptr - offsetof(type, field) );})
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/* Iterate over all items in the list */
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#define list_for_each(x, head) \
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for (x = (head)->next; x != (head); x = x->next)
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/* Iterate over all items in the list, possibly deleting some */
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#define list_for_each_safe(x, n, head) \
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for (x = (head)->next, n = x->next; x != (head); x = n, n = x->next)
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#endif /* __LIST_H__ */
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