insert.c

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#include <xinu.h>

status insert(pid32 pid, qid16 q, int32 key)
{
    qid16 curr; /* Runs through items in a queue*/
    qid16 prev; /* Holds previous node index    */

    if (isbadqid(q) || isbadpid(pid))
    {
        return SYSERR;
    }

    curr = firstid(q);
    while (queuetab[curr].qkey >= key)
    {
        curr = queuetab[curr].qnext;
    }

    /* Insert process between curr node and previous node */

    prev = queuetab[curr].qprev; /* Get index of previous node  */
    queuetab[pid].qnext = curr;
    queuetab[pid].qprev = prev;
    queuetab[pid].qkey = key;
    queuetab[prev].qnext = pid;
    queuetab[curr].qprev = pid;
    return OK;
}