1*2e2caf59SThomas Veerman /* $NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $ */
2*2e2caf59SThomas Veerman
3*2e2caf59SThomas Veerman /*
4*2e2caf59SThomas Veerman * Copyright (c) 1988, 1989, 1990, 1993
5*2e2caf59SThomas Veerman * The Regents of the University of California. All rights reserved.
6*2e2caf59SThomas Veerman *
7*2e2caf59SThomas Veerman * This code is derived from software contributed to Berkeley by
8*2e2caf59SThomas Veerman * Adam de Boor.
9*2e2caf59SThomas Veerman *
10*2e2caf59SThomas Veerman * Redistribution and use in source and binary forms, with or without
11*2e2caf59SThomas Veerman * modification, are permitted provided that the following conditions
12*2e2caf59SThomas Veerman * are met:
13*2e2caf59SThomas Veerman * 1. Redistributions of source code must retain the above copyright
14*2e2caf59SThomas Veerman * notice, this list of conditions and the following disclaimer.
15*2e2caf59SThomas Veerman * 2. Redistributions in binary form must reproduce the above copyright
16*2e2caf59SThomas Veerman * notice, this list of conditions and the following disclaimer in the
17*2e2caf59SThomas Veerman * documentation and/or other materials provided with the distribution.
18*2e2caf59SThomas Veerman * 3. Neither the name of the University nor the names of its contributors
19*2e2caf59SThomas Veerman * may be used to endorse or promote products derived from this software
20*2e2caf59SThomas Veerman * without specific prior written permission.
21*2e2caf59SThomas Veerman *
22*2e2caf59SThomas Veerman * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23*2e2caf59SThomas Veerman * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24*2e2caf59SThomas Veerman * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25*2e2caf59SThomas Veerman * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26*2e2caf59SThomas Veerman * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27*2e2caf59SThomas Veerman * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28*2e2caf59SThomas Veerman * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29*2e2caf59SThomas Veerman * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30*2e2caf59SThomas Veerman * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31*2e2caf59SThomas Veerman * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32*2e2caf59SThomas Veerman * SUCH DAMAGE.
33*2e2caf59SThomas Veerman */
34*2e2caf59SThomas Veerman
35*2e2caf59SThomas Veerman #ifndef MAKE_NATIVE
36*2e2caf59SThomas Veerman static char rcsid[] = "$NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $";
37*2e2caf59SThomas Veerman #else
38*2e2caf59SThomas Veerman #include <sys/cdefs.h>
39*2e2caf59SThomas Veerman #ifndef lint
40*2e2caf59SThomas Veerman #if 0
41*2e2caf59SThomas Veerman static char sccsid[] = "@(#)lstOpen.c 8.1 (Berkeley) 6/6/93";
42*2e2caf59SThomas Veerman #else
43*2e2caf59SThomas Veerman __RCSID("$NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $");
44*2e2caf59SThomas Veerman #endif
45*2e2caf59SThomas Veerman #endif /* not lint */
46*2e2caf59SThomas Veerman #endif
47*2e2caf59SThomas Veerman
48*2e2caf59SThomas Veerman /*-
49*2e2caf59SThomas Veerman * LstOpen.c --
50*2e2caf59SThomas Veerman * Open a list for sequential access. The sequential functions access the
51*2e2caf59SThomas Veerman * list in a slightly different way. CurPtr points to their idea of the
52*2e2caf59SThomas Veerman * current node in the list and they access the list based on it.
53*2e2caf59SThomas Veerman * If the list is circular, Lst_Next and Lst_Prev will go around
54*2e2caf59SThomas Veerman * the list forever. Lst_IsAtEnd must be used to determine when to stop.
55*2e2caf59SThomas Veerman */
56*2e2caf59SThomas Veerman
57*2e2caf59SThomas Veerman #include "lstInt.h"
58*2e2caf59SThomas Veerman
59*2e2caf59SThomas Veerman /*-
60*2e2caf59SThomas Veerman *-----------------------------------------------------------------------
61*2e2caf59SThomas Veerman * Lst_Open --
62*2e2caf59SThomas Veerman * Open a list for sequential access. A list can still be searched,
63*2e2caf59SThomas Veerman * etc., without confusing these functions.
64*2e2caf59SThomas Veerman *
65*2e2caf59SThomas Veerman * Results:
66*2e2caf59SThomas Veerman * SUCCESS or FAILURE.
67*2e2caf59SThomas Veerman *
68*2e2caf59SThomas Veerman * Side Effects:
69*2e2caf59SThomas Veerman * isOpen is set TRUE and curPtr is set to NULL so the
70*2e2caf59SThomas Veerman * other sequential functions no it was just opened and can choose
71*2e2caf59SThomas Veerman * the first element accessed based on this.
72*2e2caf59SThomas Veerman *
73*2e2caf59SThomas Veerman *-----------------------------------------------------------------------
74*2e2caf59SThomas Veerman */
75*2e2caf59SThomas Veerman ReturnStatus
Lst_Open(Lst l)76*2e2caf59SThomas Veerman Lst_Open(Lst l)
77*2e2caf59SThomas Veerman {
78*2e2caf59SThomas Veerman if (LstValid (l) == FALSE) {
79*2e2caf59SThomas Veerman return (FAILURE);
80*2e2caf59SThomas Veerman }
81*2e2caf59SThomas Veerman (l)->isOpen = TRUE;
82*2e2caf59SThomas Veerman (l)->atEnd = LstIsEmpty (l) ? Head : Unknown;
83*2e2caf59SThomas Veerman (l)->curPtr = NULL;
84*2e2caf59SThomas Veerman
85*2e2caf59SThomas Veerman return (SUCCESS);
86*2e2caf59SThomas Veerman }
87*2e2caf59SThomas Veerman
88