1 /* ========================================================================== **
4 * Copyright (C) 1997, 1998 by Christopher R. Hertel
6 * Email: crh@ubiqx.mn.org
7 * -------------------------------------------------------------------------- **
8 * This module implements simple doubly-linked lists.
9 * -------------------------------------------------------------------------- **
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Library General Public
13 * License as published by the Free Software Foundation; either
14 * version 2 of the License, or (at your option) any later version.
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Library General Public License for more details.
21 * You should have received a copy of the GNU Library General Public
22 * License along with this library; if not, write to the Free
23 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 * -------------------------------------------------------------------------- **
27 * Log: ubi_dLinkList.c,v
28 * Revision 0.7 1998/06/02 01:38:47 crh
29 * Changed include file name from ubi_null.h to sys_include.h to make it
32 * Revision 0.6 1998/05/20 04:38:05 crh
33 * The C file now includes ubi_null.h. See ubi_null.h for more info.
35 * Revision 0.5 1998/03/10 02:55:00 crh
36 * Simplified the code and added macros for stack & queue manipulations.
38 * Revision 0.4 1998/01/03 01:53:56 crh
39 * Added ubi_dlCount() macro.
41 * Revision 0.3 1997/10/15 03:05:39 crh
42 * Added some handy type casting to the macros. Added AddHere and RemThis
45 * Revision 0.2 1997/10/08 03:07:21 crh
46 * Fixed a few forgotten link-ups in Insert(), and fixed the AddHead()
47 * macro, which was passing the wrong value for <After> to Insert().
49 * Revision 0.1 1997/10/07 04:34:07 crh
52 * -------------------------------------------------------------------------- **
53 * This module is similar to the ubi_sLinkList module, but it is neither a
54 * descendant type nor an easy drop-in replacement for the latter. One key
55 * difference is that the ubi_dlRemove() function removes the indicated node,
56 * while the ubi_slRemove() function (in ubi_sLinkList) removes the node
57 * *following* the indicated node.
59 * ========================================================================== **
62 #include "sys_include.h" /* System-specific includes. */
63 #include "ubi_dLinkList.h" /* Header for *this* module. */
65 /* ========================================================================== **
69 ubi_dlListPtr ubi_dlInitList( ubi_dlListPtr ListPtr )
70 /* ------------------------------------------------------------------------ **
71 * Initialize a doubly-linked list header.
73 * Input: ListPtr - A pointer to the list structure that is to be
74 * initialized for use.
76 * Output: A pointer to the initialized list header (i.e., same as
79 * ------------------------------------------------------------------------ **
86 } /* ubi_dlInitList */
88 ubi_dlNodePtr ubi_dlInsert( ubi_dlListPtr ListPtr,
91 /* ------------------------------------------------------------------------ **
92 * Insert a new node into the list.
94 * Input: ListPtr - A pointer to the list into which the node is to
96 * New - Pointer to the new node.
97 * After - NULL, or a pointer to a node that is already in the
99 * If NULL, then <New> will be added at the head of the
100 * list, else it will be added following <After>.
102 * Output: A pointer to the node that was inserted into the list (i.e.,
103 * the same as <New>).
105 * ------------------------------------------------------------------------ **
108 ubi_dlNodePtr PredNode = After ? After : (ubi_dlNodePtr)ListPtr;
110 New->Next = PredNode->Next;
112 PredNode->Next = New;
114 New->Next->Prev = New;
123 ubi_dlNodePtr ubi_dlRemove( ubi_dlListPtr ListPtr, ubi_dlNodePtr Old )
124 /* ------------------------------------------------------------------------ **
125 * Remove a node from the list.
127 * Input: ListPtr - A pointer to the list from which <Old> is to be
129 * Old - A pointer to the node that is to be removed from the
132 * Output: A pointer to the node that was removed (i.e., <Old>).
134 * ------------------------------------------------------------------------ **
140 Old->Next->Prev = Old->Prev;
142 ListPtr->Tail = Old->Prev;
145 Old->Prev->Next = Old->Next;
147 ListPtr->Head = Old->Next;
155 /* ================================ The End ================================= */