/* * 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 WALK_LIST(n,list) for(n=HEAD(list);(NODE (n))->next; \ n=(void *)((NODE (n))->next)) #define WALK_LIST_DELSAFE(n,nxt,list) \ for(n=HEAD(list); nxt=(void *)((NODE (n))->next); n=(void *) nxt) #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