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/*
* BIRD Library -- Linked Lists
*
* (c) 1998 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _BIRD_LISTS_H_
#define _BIRD_LISTS_H_
/*
* I admit the list structure is very tricky and also somewhat awkward,
* but it's both efficient and easy to manipulate once one understands the
* basic trick: The list head always contains two synthetic nodes which are
* always present in the list: the head and the tail. But as the `next'
* entry of the tail and the `prev' entry of the head are both NULL, the
* nodes can overlap each other:
*
* head head_node.next
* null head_node.prev tail_node.next
* tail tail_node.prev
*/
typedef struct node {
struct node *next, *prev;
} node;
typedef struct list { /* In fact two overlayed nodes */
struct node *head, *null, *tail;
} list;
#define NODE (node *)
#define HEAD(list) ((void *)((list).head))
#define TAIL(list) ((void *)((list).tail))
#define NODE_NEXT(n) ((void *)((NODE (n))->next))
#define WALK_LIST(n,list) for(n=HEAD(list);(NODE (n))->next; n=NODE_NEXT(n))
#define WALK_LIST_DELSAFE(n,nxt,list) \
for(n=HEAD(list); nxt=NODE_NEXT(n); n=(void *) nxt)
/* WALK_LIST_FIRST supposes that called code removes each processed node */
#define WALK_LIST_FIRST(n,list) \
while(n=HEAD(list), (NODE (n))->next)
#define WALK_LIST_BACKWARDS(n,list) for(n=TAIL(list);(NODE (n))->prev; \
n=(void *)((NODE (n))->prev))
#define WALK_LIST_BACKWARDS_DELSAFE(n,prv,list) \
for(n=TAIL(list); prv=(void *)((NODE (n))->prev); n=(void *) prv)
#define EMPTY_LIST(list) (!(list).head->next)
void add_tail(list *, node *);
void add_head(list *, node *);
void rem_node(node *);
void add_tail_list(list *, list *);
void init_list(list *);
void insert_node(node *, node *);
#ifndef _BIRD_LISTS_C_
#define LIST_INLINE extern inline
#include "lib/lists.c"
#undef LIST_INLINE
#else
#define LIST_INLINE
#endif
#endif
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