atc/list.c

   1 /*      $NetBSD: list.c,v 1.7 2005/07/01 00:48:34 jmc 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 1.7 2005/07/01 00:48:34 jmc Exp $");
  50 #endif
  51 #endif /* not lint */
  52
  53 #include "include.h"
  54
  55 PLANE *
  56 newplane(void)
  57 {
  58         return ((PLANE *) calloc(1, sizeof (PLANE)));
  59 }
  60
  61 void
  62 append(LIST *l, PLANE *p)
  63 {
  64         PLANE   *q = NULL, *r = NULL;
  65
  66         if (l->head == NULL) {
  67                 p->next = p->prev = NULL;
  68                 l->head = l->tail = p;
  69         } else {
  70                 q = l -> head;
  71
  72                 while (q != NULL && q->plane_no < p->plane_no) {
  73                         r = q;
  74                         q = q -> next;
  75                 }
  76
  77                 if (q) {
  78                         if (r) {
  79                                 p->prev = r;
  80                                 r->next = p;
  81                                 p->next = q;
  82                                 q->prev = p;
  83                         } else {
  84                                 p->next = q;
  85                                 p->prev = NULL;
  86                                 q->prev = p;
  87                                 l->head = p;
  88                         }
  89                 } else {
  90                         l->tail->next = p;
  91                         p->next = NULL;
  92                         p->prev = l->tail;
  93                         l->tail = p;
  94                 }
  95         }
  96 }
  97
  98 void
  99 delete(LIST *l, PLANE *p)
 100 {
 101         if (l->head == NULL)
 102                 loser(p, "deleted a non-existent plane! Get help!");
 103
 104         if (l->head == p && l->tail == p)
 105                 l->head = l->tail = NULL;
 106         else if (l->head == p) {
 107                 l->head = p->next;
 108                 l->head->prev = NULL;
 109         } else if (l->tail == p) {
 110                 l->tail = p->prev;
 111                 l->tail->next = NULL;
 112         } else {
 113                 p->prev->next = p->next;
 114                 p->next->prev = p->prev;
 115         }
 116 }