1: /*      $NetBSD: list.c,v 1.6 2003/08/07 09:36:54 agc Exp $  */
    2: 
    3: /*-
    4:  * Copyright (c) 1990, 1993
    5:  *      The Regents of the University of California.  All rights reserved.
    6:  *
    7:  * This code is derived from software contributed to Berkeley by
    8:  * Ed James.
    9:  *
   10:  * Redistribution and use in source and binary forms, with or without
   11:  * modification, are permitted provided that the following conditions
   12:  * are met:
   13:  * 1. Redistributions of source code must retain the above copyright
   14:  *    notice, this list of conditions and the following disclaimer.
   15:  * 2. Redistributions in binary form must reproduce the above copyright
   16:  *    notice, this list of conditions and the following disclaimer in the
   17:  *    documentation and/or other materials provided with the distribution.
   18:  * 3. Neither the name of the University nor the names of its contributors
   19:  *    may be used to endorse or promote products derived from this software
   20:  *    without specific prior written permission.
   21:  *
   22:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32:  * SUCH DAMAGE.
   33:  */
   34: 
   35: /*
   36:  * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
   37:  *
   38:  * Copy permission is hereby granted provided that this notice is
   39:  * retained on all partial or complete copies.
   40:  *
   41:  * For more info on this and all of my stuff, mail edjames@berkeley.edu.
   42:  */
   43: 
   44: #include <sys/cdefs.h>
   45: #ifndef lint
   46: #if 0
   47: static char sccsid[] = "@(#)list.c      8.1 (Berkeley) 5/31/93";
   48: #else
   49: __RCSID("$NetBSD: list.c,v 1.6 2003/08/07 09:36:54 agc Exp $");
   50: #endif
   51: #endif /* not lint */
   52: 
   53: #include "include.h"
   54: 
   55: PLANE   *
   56: newplane()
   57: {
   58:         return ((PLANE *) calloc(1, sizeof (PLANE)));
   59: }
   60: 
   61: void
   62: append(l, p)
   63:         LIST   *l;
   64:         PLANE  *p;
   65: {
   66:         PLANE  *q = NULL, *r = NULL;
   67: 
   68:         if (l->head == NULL) {
   69:                 p->next = p->prev = NULL;
   70:                 l->head = l->tail = p;
   71:         } else {
   72:                 q = l -> head;
   73: 
   74:                 while (q != NULL && q->plane_no < p->plane_no) {
   75:                         r = q;
   76:                         q = q -> next;
   77:                 }
   78: 
   79:                 if (q) {
   80:                         if (r) {
   81:                                 p->prev = r;
   82:                                 r->next = p;
   83:                                 p->next = q;
   84:                                 q->prev = p;
   85:                         } else {
   86:                                 p->next = q;
   87:                                 p->prev = NULL;
   88:                                 q->prev = p;
   89:                                 l->head = p;
   90:                         }
   91:                 } else {
   92:                         l->tail->next = p;
   93:                         p->next = NULL;
   94:                         p->prev = l->tail;
   95:                         l->tail = p;
   96:                 }
   97:         }
   98: }
   99: 
  100: void
  101: delete(l, p)
  102:         LIST   *l;
  103:         PLANE  *p;
  104: {
  105:         if (l->head == NULL)
  106:                 loser(p, "deleted a non-existent plane! Get help!");
  107:         
  108:         if (l->head == p && l->tail == p)
  109:                 l->head = l->tail = NULL;
  110:         else if (l->head == p) {
  111:                 l->head = p->next;
  112:                 l->head->prev = NULL;
  113:         } else if (l->tail == p) {
  114:                 l->tail = p->prev;
  115:                 l->tail->next = NULL;
  116:         } else {
  117:                 p->prev->next = p->next;
  118:                 p->next->prev = p->prev;
  119:         }
  120: }