#ifndef LIST_H_
#define LIST_H_

/*=* Linked list macros *=*/
#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_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 { \
		(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 { \
		(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 { \
		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)

#ifndef NTRACE
/* enable tracing of some LIST_xxx macros */
# define LIST_INSERT_HEAD_trace(head, elm, name) do { \
		DEBUG("LIST_INSERT_HEAD:Inserting %p\n", (void*)elm); \
		LIST_INSERT_HEAD_(head, elm, name); \
	} while(0)
# define LIST_REMOVE_trace(elm, name) do { \
		DEBUG("LIST_REMOVE:Removing %p\n", (void*)elm); \
		LIST_REMOVE_(elm, name); \
	} while(0)
# define LIST_INSERT_HEAD LIST_INSERT_HEAD_trace
# define LIST_REMOVE LIST_REMOVE_trace
#else
/* use non-tracing version */
#define LIST_INSERT_HEAD LIST_INSERT_HEAD_
#define LIST_REMOVE LIST_REMOVE_
#endif

/******* TODO TODO TODO : write unit test for LIST_xxx macros *******/

#endif