68 lines
2 KiB
C
68 lines
2 KiB
C
/*
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* BIRD Library -- Linked Lists
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*
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* (c) 1998 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_LISTS_H_
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#define _BIRD_LISTS_H_
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/*
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* I admit the list structure is very tricky and also somewhat awkward,
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* but it's both efficient and easy to manipulate once one understands the
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* basic trick: The list head always contains two synthetic nodes which are
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* always present in the list: the head and the tail. But as the `next'
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* entry of the tail and the `prev' entry of the head are both NULL, the
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* nodes can overlap each other:
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*
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* head head_node.next
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* null head_node.prev tail_node.next
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* tail tail_node.prev
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*/
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typedef struct node {
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struct node *next, *prev;
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} node;
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typedef struct list { /* In fact two overlayed nodes */
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struct node *head, *null, *tail;
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} list;
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#define NODE (node *)
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#define HEAD(list) ((void *)((list).head))
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#define TAIL(list) ((void *)((list).tail))
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#define NODE_NEXT(n) ((void *)((NODE (n))->next))
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#define NODE_VALID(n) ((NODE (n))->next)
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#define WALK_LIST(n,list) for(n=HEAD(list); NODE_VALID(n); n=NODE_NEXT(n))
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#define WALK_LIST_DELSAFE(n,nxt,list) \
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for(n=HEAD(list); nxt=NODE_NEXT(n); n=(void *) nxt)
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/* WALK_LIST_FIRST supposes that called code removes each processed node */
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#define WALK_LIST_FIRST(n,list) \
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while(n=HEAD(list), (NODE (n))->next)
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#define WALK_LIST_BACKWARDS(n,list) for(n=TAIL(list);(NODE (n))->prev; \
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n=(void *)((NODE (n))->prev))
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#define WALK_LIST_BACKWARDS_DELSAFE(n,prv,list) \
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for(n=TAIL(list); prv=(void *)((NODE (n))->prev); n=(void *) prv)
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#define EMPTY_LIST(list) (!(list).head->next)
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void add_tail(list *, node *);
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void add_head(list *, node *);
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void rem_node(node *);
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void rem2_node(node *);
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void add_tail_list(list *, list *);
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void init_list(list *);
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void insert_node(node *, node *);
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#ifndef _BIRD_LISTS_C_
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#define LIST_INLINE extern inline
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#include "lib/lists.c"
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#undef LIST_INLINE
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#else
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#define LIST_INLINE
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#endif
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#endif
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