/* list.h - Linked List macros inspired by BSD queue.h
 * Jon Mayo <jon.mayo@gmail.com>
 * PUBLIC DOMAIN - December 5, 2008
 */
#ifndef LIST_H
#define LIST_H

/* linked lists with double pointers */
#define LIST_ENTRY(type) struct { type *_next, **_prev; }
#define LIST_HEAD(headname, type) headname { type *_head; }
#define LIST_INIT(head) ((head)->_head=NULL)
#define LIST_ENTRY_INIT(elm, name) do { (elm)->name._next=NULL; (elm)->name._prev=NULL; } while(0)
#define LIST_TOP(head) ((head)._head)
#define LIST_NEXT(elm, name) ((elm)->name._next)
#define LIST_ISEMPTY(head) ((head)->_head==NULL)
#define LIST_PREVPTR(elm, name) ((elm)->name._prev)
#define LIST_INSERT_ATPTR(prevptr, elm, name) do { \
	(elm)->name._prev=(prevptr); \
	if(((elm)->name._next=*(prevptr))!=NULL) \
		(elm)->name._next->name._prev=&(elm)->name._next; \
	*(prevptr)=(elm); \
	} while(0)
#define LIST_INSERT_AFTER(where, elm, name) do { \
		assert(where != NULL && elm != NULL); \
		(elm)->name._prev=&(where)->name._next; \
		if(((elm)->name._next=(where)->name._next)!=NULL) \
			(where)->name._next->name._prev=&(elm)->name._next; \
		*(elm)->name._prev=(elm); \
	} while(0)
#define LIST_INSERT_HEAD(head, elm, name) do { \
		assert(head != NULL && elm != NULL); \
		(elm)->name._prev=&(head)->_head; \
		if(((elm)->name._next=(head)->_head)!=NULL) \
			(head)->_head->name._prev=&(elm)->name._next; \
		(head)->_head=(elm); \
	} while(0)
#define LIST_REMOVE(elm, name) do { \
		assert(elm != NULL); \
		if((elm)->name._next!=NULL) \
			(elm)->name._next->name._prev=(elm)->name._prev; \
		if((elm)->name._prev) \
			*(elm)->name._prev=(elm)->name._next; \
	} while(0)
#define LIST_REMOVE_HEAD(head, name) LIST_REMOVE(LIST_TOP(head), name)
#define LIST_TAIL_ADD(tailptr, elm, name) do { \
		assert(tailptr != NULL && elm != NULL); \
		(elm)->name._prev=(tailptr); \
		*(tailptr)=(elm); \
		(tailptr)=&(elm)->name._next; \
	} while(0)
#define LIST_TAIL_INIT(head, tailptr) (tailptr)=&LIST_TOP(head)
#define LIST_FOREACH(i_var, head, name) \
	for((i_var)=LIST_TOP(head);(i_var);(i_var)=LIST_NEXT(i_var, name))


/* singly linked lists */
#define SLIST_ENTRY(type) struct { type *_next; }
#define SLIST_HEAD(headname, type) headname { type *_head; }
#define SLIST_INIT(head) ((head)->_head=NULL)
#define SLIST_ENTRY_INIT(elm, name) do { (elm)->name._next=NULL; } while(0)
#define SLIST_TOP(head) ((head)._head)
#define SLIST_NEXT(elm, name) ((elm)->name._next)
#define SLIST_ISEMPTY(head) ((head)->_head==NULL)
#define SLIST_INSERT_HEAD(head, elm, name) do { \
		assert(head != NULL && elm != NULL); \
		(elm)->name._next=(head)->_head; \
		(head)->_head=(elm); \
	} while(0)
/* nextptr : pointer to the previous element's next field or pointer to the _head pointer */
#define SLIST_REMOVE(elm, name, nextptr) do { \
		assert(elm != NULL); \
		assert(nextptr != NULL); \
		*(nextptr)=(elm)->name._next; \
		(elm)->name._next=NULL; \
	} while(0)
#define SLIST_REMOVE_HEAD(head, name) do { \
		void *_tmp; \
		assert(head != NULL); \
		_tmp=SLIST_NEXT((head)->_head, name); \
		SLIST_NEXT((head)->_head, name)=NULL; \
		(head)->_head=_tmp; \
	} while(0)
#define SLIST_INSERT_AFTER(where, elm, name) do { \
		assert((where) != NULL && (elm) != NULL); \
		SLIST_NEXT((elm), name)=SLIST_NEXT((where), name); \
		SLIST_NEXT((where), name)=(elm); \
	} while(0)
#define SLIST_FOREACH(i_var, head, name) \
	for((i_var)=SLIST_TOP(head);(i_var);(i_var)=SLIST_NEXT(i_var, name))

#endif