atc/list.c

   1 /*-
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Ed James.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 /*
  38  * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
  39  *
  40  * Copy permission is hereby granted provided that this notice is
  41  * retained on all partial or complete copies.
  42  *
  43  * For more info on this and all of my stuff, mail edjames@berkeley.edu.
  44  */
  45
  46 #ifndef lint
  47 /*static char sccsid[] = "from: @(#)list.c      5.2 (Berkeley) 4/30/90";*/
  48 static char rcsid[] = "$Id: list.c,v 1.2 1993/08/01 18:57:05 mycroft Exp $";
  49 #endif /* not lint */
  50
  51 #include "include.h"
  52
  53 PLANE   *
  54 newplane()
  55 {
  56         return ((PLANE *) calloc(1, sizeof (PLANE)));
  57 }
  58
  59 append(l, p)
  60         LIST    *l;
  61         PLANE   *p;
  62 {
  63         PLANE   *q = NULL, *r = NULL;
  64
  65         if (l->head == NULL) {
  66                 p->next = p->prev = NULL;
  67                 l->head = l->tail = p;
  68         } else {
  69                 q = l -> head;
  70
  71                 while (q != NULL && q->plane_no < p->plane_no) {
  72                         r = q;
  73                         q = q -> next;
  74                 }
  75
  76                 if (q) {
  77                         if (r) {
  78                                 p->prev = r;
  79                                 r->next = p;
  80                                 p->next = q;
  81                                 q->prev = p;
  82                         } else {
  83                                 p->next = q;
  84                                 p->prev = NULL;
  85                                 q->prev = p;
  86                                 l->head = p;
  87                         }
  88                 } else {
  89                         l->tail->next = p;
  90                         p->next = NULL;
  91                         p->prev = l->tail;
  92                         l->tail = p;
  93                 }
  94         }
  95 }
  96
  97 delete(l, p)
  98         LIST    *l;
  99         PLANE   *p;
 100 {
 101         if (l->head == NULL)
 102                 loser(p, "deleted a non-existant 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 }