Commit | Line | Data |
---|---|---|
bb2109e7 KB |
1 | /* |
2 | * Copyright (c) 1988, 1989, 1990 The Regents of the University of California. | |
3 | * All rights reserved. | |
c65fedcf | 4 | * |
bb2109e7 KB |
5 | * This code is derived from software contributed to Berkeley by |
6 | * Adam de Boor. | |
c65fedcf | 7 | * |
af359dea C |
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. | |
c65fedcf | 35 | */ |
bb2109e7 | 36 | |
c65fedcf | 37 | #ifndef lint |
1c15e888 | 38 | static char sccsid[] = "@(#)lstRemove.c 5.3 (Berkeley) 6/1/90"; |
bb2109e7 KB |
39 | #endif /* not lint */ |
40 | ||
41 | /*- | |
42 | * LstRemove.c -- | |
43 | * Remove an element from a list | |
44 | */ | |
c65fedcf KB |
45 | |
46 | #include "lstInt.h" | |
47 | ||
48 | /*- | |
49 | *----------------------------------------------------------------------- | |
50 | * Lst_Remove -- | |
51 | * Remove the given node from the given list. | |
52 | * | |
53 | * Results: | |
54 | * SUCCESS or FAILURE. | |
55 | * | |
56 | * Side Effects: | |
57 | * The list's firstPtr will be set to NilListNode if ln is the last | |
58 | * node on the list. firsPtr and lastPtr will be altered if ln is | |
59 | * either the first or last node, respectively, on the list. | |
60 | * | |
61 | *----------------------------------------------------------------------- | |
62 | */ | |
63 | ReturnStatus | |
64 | Lst_Remove (l, ln) | |
65 | Lst l; | |
66 | LstNode ln; | |
67 | { | |
68 | register List list = (List) l; | |
69 | register ListNode lNode = (ListNode) ln; | |
70 | ||
71 | if (!LstValid (l) || | |
72 | !LstNodeValid (ln, l)) { | |
73 | return (FAILURE); | |
74 | } | |
75 | ||
76 | /* | |
77 | * unlink it from the list | |
78 | */ | |
79 | if (lNode->nextPtr != NilListNode) { | |
80 | lNode->nextPtr->prevPtr = lNode->prevPtr; | |
81 | } | |
82 | if (lNode->prevPtr != NilListNode) { | |
83 | lNode->prevPtr->nextPtr = lNode->nextPtr; | |
84 | } | |
85 | ||
86 | /* | |
87 | * if either the firstPtr or lastPtr of the list point to this node, | |
88 | * adjust them accordingly | |
89 | */ | |
90 | if (list->firstPtr == lNode) { | |
91 | list->firstPtr = lNode->nextPtr; | |
92 | } | |
93 | if (list->lastPtr == lNode) { | |
94 | list->lastPtr = lNode->prevPtr; | |
95 | } | |
96 | ||
97 | /* | |
98 | * Sequential access stuff. If the node we're removing is the current | |
99 | * node in the list, reset the current node to the previous one. If the | |
100 | * previous one was non-existent (prevPtr == NilListNode), we set the | |
101 | * end to be Unknown, since it is. | |
102 | */ | |
103 | if (list->isOpen && (list->curPtr == lNode)) { | |
104 | list->curPtr = list->prevPtr; | |
105 | if (list->curPtr == NilListNode) { | |
106 | list->atEnd = Unknown; | |
107 | } | |
108 | } | |
109 | ||
110 | /* | |
111 | * the only way firstPtr can still point to ln is if ln is the last | |
112 | * node on the list (the list is circular, so lNode->nextptr == lNode in | |
113 | * this case). The list is, therefore, empty and is marked as such | |
114 | */ | |
115 | if (list->firstPtr == lNode) { | |
116 | list->firstPtr = NilListNode; | |
117 | } | |
118 | ||
119 | /* | |
120 | * note that the datum is unmolested. The caller must free it as | |
121 | * necessary and as expected. | |
122 | */ | |
123 | if (lNode->useCount == 0) { | |
124 | free ((Address)ln); | |
125 | } else { | |
126 | lNode->flags |= LN_DELETED; | |
127 | } | |
128 | ||
129 | return (SUCCESS); | |
130 | } | |
131 |