1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright (C) 2001 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <dwmw2@cambridge.redhat.com>
7 *
8 * The original JFFS, from which the design for JFFS2 was derived,
9 * was designed and implemented by Axis Communications AB.
10 *
11 * The contents of this file are subject to the Red Hat eCos Public
12 * License Version 1.1 (the "Licence"); you may not use this file
13 * except in compliance with the Licence. You may obtain a copy of
14 * the Licence at http://www.redhat.com/
15 *
16 * Software distributed under the Licence is distributed on an "AS IS"
17 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
18 * See the Licence for the specific language governing rights and
19 * limitations under the Licence.
20 *
21 * The Original Code is JFFS2 - Journalling Flash File System, version 2
22 *
23 * Alternatively, the contents of this file may be used under the
24 * terms of the GNU General Public License version 2 (the "GPL"), in
25 * which case the provisions of the GPL are applicable instead of the
26 * above. If you wish to allow the use of your version of this file
27 * only under the terms of the GPL and not to allow others to use your
28 * version of this file under the RHEPL, indicate your decision by
29 * deleting the provisions above and replace them with the notice and
30 * other provisions required by the GPL. If you do not delete the
31 * provisions above, a recipient may use your version of this file
32 * under either the RHEPL or the GPL.
33 *
34 * $Id: pushpull.c,v 1.7 2001/09/23 10:04:15 rmk Exp $
35 *
36 */
37
38 #include <linux/string.h>
39 #include "pushpull.h"
40 #include <linux/errno.h>
41
init_pushpull(struct pushpull * pp,char * buf,unsigned buflen,unsigned ofs,unsigned reserve)42 void init_pushpull(struct pushpull *pp, char *buf, unsigned buflen, unsigned ofs, unsigned reserve)
43 {
44 pp->buf = buf;
45 pp->buflen = buflen;
46 pp->ofs = ofs;
47 pp->reserve = reserve;
48 }
49
50
pushbit(struct pushpull * pp,int bit,int use_reserved)51 int pushbit(struct pushpull *pp, int bit, int use_reserved)
52 {
53 if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve)) {
54 return -ENOSPC;
55 }
56
57 if (bit) {
58 pp->buf[pp->ofs >> 3] |= (1<<(7-(pp->ofs &7)));
59 }
60 else {
61 pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs &7)));
62 }
63 pp->ofs++;
64
65 return 0;
66 }
67
pushedbits(struct pushpull * pp)68 int pushedbits(struct pushpull *pp)
69 {
70 return pp->ofs;
71 }
72