[deliverable/binutils-gdb.git] / libiberty / insque.c

/* insque(3C) routines
   This file is in the public domain.  */

/*

@deftypefn Supplemental void insque (struct qelem *@var{elem}, struct qelem *@var{pred})
@deftypefnx Supplemental void remque (struct qelem *@var{elem})

Routines to manipulate queues built from doubly linked lists.  The
@code{insque} routine inserts @var{elem} in the queue immediately
after @var{pred}.  The @code{remque} routine removes @var{elem} from
its containing queue.  These routines expect to be passed pointers to
structures which have as their first members a forward pointer and a
back pointer, like this prototype (although no prototype is provided):

@example
struct qelem @{
  struct qelem *q_forw;
  struct qelem *q_back;
  char q_data[];
@};
@end example

@end deftypefn

*/


struct qelem {
  struct qelem *q_forw;
  struct qelem *q_back;
};


void
insque (elem, pred)
  struct qelem *elem;
  struct qelem *pred;
{
  elem -> q_forw = pred -> q_forw;
  pred -> q_forw -> q_back = elem;
  elem -> q_back = pred;
  pred -> q_forw = elem;
}


void
remque (elem)
  struct qelem *elem;
{
  elem -> q_forw -> q_back = elem -> q_back;
  elem -> q_back -> q_forw = elem -> q_forw;
}
Commit	Line	Data
	1	/* insque(3C) routines
	2	This file is in the public domain. */
	3
	4	/*
	5
	6	@deftypefn Supplemental void insque (struct qelem @var{elem}, struct qelem @var{pred})
	7	@deftypefnx Supplemental void remque (struct qelem *@var{elem})
	8
	9	Routines to manipulate queues built from doubly linked lists. The
	10	@code{insque} routine inserts @var{elem} in the queue immediately
	11	after @var{pred}. The @code{remque} routine removes @var{elem} from
	12	its containing queue. These routines expect to be passed pointers to
	13	structures which have as their first members a forward pointer and a
	14	back pointer, like this prototype (although no prototype is provided):
	15
	16	@example
	17	struct qelem @{
	18	struct qelem *q_forw;
	19	struct qelem *q_back;
	20	char q_data[];
	21	@};
	22	@end example
	23
	24	@end deftypefn
	25
	26	*/
	27
	28
	29	struct qelem {
	30	struct qelem *q_forw;
	31	struct qelem *q_back;
	32	};
	33
	34
	35	void
	36	insque (elem, pred)
	37	struct qelem *elem;
	38	struct qelem *pred;
	39	{
	40	elem -> q_forw = pred -> q_forw;
	41	pred -> q_forw -> q_back = elem;
	42	elem -> q_back = pred;
	43	pred -> q_forw = elem;
	44	}
	45
	46
	47	void
	48	remque (elem)
	49	struct qelem *elem;
	50	{
	51	elem -> q_forw -> q_back = elem -> q_back;
	52	elem -> q_back -> q_forw = elem -> q_forw;
	53	}