1 /* $OpenBSD: list.c,v 1.9 2015/12/31 16:50:29 mestre Exp $ */
2 /* $NetBSD: list.c,v 1.3 1995/03/21 15:04:18 cgd Exp $ */
3
4 /*-
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Ed James.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * Copyright (c) 1987 by Ed James, UC Berkeley. All rights reserved.
38 *
39 * Copy permission is hereby granted provided that this notice is
40 * retained on all partial or complete copies.
41 *
42 * For more info on this and all of my stuff, mail edjames@berkeley.edu.
43 */
44
45 #include <stdlib.h>
46
47 #include "extern.h"
48
49 PLANE *
newplane(void)50 newplane(void)
51 {
52 PLANE *p;
53
54 if ((p = calloc(1, sizeof (PLANE))) == NULL)
55 loser(NULL, "Out of memory");
56 return (p);
57 }
58
59 void
append(LIST * l,PLANE * p)60 append(LIST *l, PLANE *p)
61 {
62 PLANE *q = NULL, *r = NULL;
63
64 if (l->head == NULL) {
65 p->next = p->prev = NULL;
66 l->head = l->tail = p;
67 } else {
68 q = l -> head;
69
70 while (q != NULL && q->plane_no < p->plane_no) {
71 r = q;
72 q = q -> next;
73 }
74
75 if (q) {
76 if (r) {
77 p->prev = r;
78 r->next = p;
79 p->next = q;
80 q->prev = p;
81 } else {
82 p->next = q;
83 p->prev = NULL;
84 q->prev = p;
85 l->head = p;
86 }
87 } else {
88 l->tail->next = p;
89 p->next = NULL;
90 p->prev = l->tail;
91 l->tail = p;
92 }
93 }
94 }
95
96 void
delete(LIST * l,PLANE * p)97 delete(LIST *l, PLANE *p)
98 {
99 if (l->head == NULL)
100 loser(p, "deleted a non-existent plane! Get help!");
101
102 if (l->head == p && l->tail == p)
103 l->head = l->tail = NULL;
104 else if (l->head == p) {
105 l->head = p->next;
106 l->head->prev = NULL;
107 } else if (l->tail == p) {
108 l->tail = p->prev;
109 l->tail->next = NULL;
110 } else {
111 p->prev->next = p->next;
112 p->next->prev = p->prev;
113 }
114 }
115