/*      $NetBSD: list.c,v 1.10 2021/05/02 12:50:43 rillig Exp $ */

/*-
* Copyright (c) 1990, 1993
*      The Regents of the University of California.  All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ed James.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

/*
* Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
*
* Copy permission is hereby granted provided that this notice is
* retained on all partial or complete copies.
*
* For more info on this and all of my stuff, mail [email protected].
*/

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)list.c      8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: list.c,v 1.10 2021/05/02 12:50:43 rillig Exp $");
#endif
#endif /* not lint */

#include <stdlib.h>

#include "def.h"
#include "struct.h"
#include "extern.h"
#include "tunable.h"

PLANE *
newplane(void)
{
       return calloc(1, sizeof (PLANE));
}

void
append(LIST *l, PLANE *p)
{
       PLANE   *q = NULL, *r = NULL;

       if (l->head == NULL) {
               p->next = p->prev = NULL;
               l->head = l->tail = p;
       } else {
               q = l -> head;

               while (q != NULL && q->plane_no < p->plane_no) {
                       r = q;
                       q = q -> next;
               }

               if (q) {
                       if (r) {
                               p->prev = r;
                               r->next = p;
                               p->next = q;
                               q->prev = p;
                       } else {
                               p->next = q;
                               p->prev = NULL;
                               q->prev = p;
                               l->head = p;
                       }
               } else {
                       l->tail->next = p;
                       p->next = NULL;
                       p->prev = l->tail;
                       l->tail = p;
               }
       }
}

void
delete(LIST *l, PLANE *p)
{
       if (l->head == NULL)
               loser(p, "deleted a non-existent plane! Get help!");

       if (l->head == p && l->tail == p)
               l->head = l->tail = NULL;
       else if (l->head == p) {
               l->head = p->next;
               l->head->prev = NULL;
       } else if (l->tail == p) {
               l->tail = p->prev;
               l->tail->next = NULL;
       } else {
               p->prev->next = p->next;
               p->next->prev = p->prev;
       }
}