insert.c

TCP-IP红宝书源代码

/* insert.c  -  insert */

#include <conf.h>
#include <kernel.h>
#include <q.h>

/*------------------------------------------------------------------------
 * insert.c  --  insert an process into a q list in key order
 *------------------------------------------------------------------------
 */
int	insert(proc, head, key)
	int	proc;			/* process to insert		*/
	int	head;			/* q index of head of list	*/
	int	key;			/* key to use for this process	*/
{
	int	next;			/* runs through list		*/
	int	prev;

	next = q[head].qnext;
	while (q[next].qkey < key)	/* tail has maxint as key	*/
		next = q[next].qnext;
	q[proc].qnext = next;
	q[proc].qprev = prev = q[next].qprev;
	q[proc].qkey  = key;
	q[prev].qnext = proc;
	q[next].qprev = proc;
	return(OK);
}