1/*
2 * macros to convert each packed bitfield structure from little endian to big
3 * endian and vice versa.  These are needed when creating a filesystem on a
4 * machine with different byte ordering to the target architecture.
5 *
6 * Copyright (c) 2002, 2003, 2004 Phillip Lougher <plougher@users.sourceforge.net>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2,
11 * or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 *
22 * mksquashfs.h
23 *
24 */
25
26/*
27 * macros used to swap each structure entry, taking into account
28 * bitfields and different bitfield placing conventions on differing architectures
29 */
30#if __BYTE_ORDER == __BIG_ENDIAN
31	/* convert from big endian to little endian */
32#define SQUASHFS_SWAP(value, p, pos, tbits) _SQUASHFS_SWAP(value, p, pos, tbits, b_pos)
33#else
34	/* convert from little endian to big endian */
35#define SQUASHFS_SWAP(value, p, pos, tbits) _SQUASHFS_SWAP(value, p, pos, tbits, 64 - tbits - b_pos)
36#endif
37
38#define _SQUASHFS_SWAP(value, p, pos, tbits, SHIFT) {\
39	int bits;\
40	int b_pos = pos % 8;\
41	unsigned long long val = (long long) value << (SHIFT);\
42	unsigned char *s = ((unsigned char *) &val) + 7;\
43	unsigned char *d = ((unsigned char *)p) + (pos / 8);\
44	for(bits = 0; bits < (tbits + b_pos); bits += 8) \
45		*d++ |= *s--;\
46}
47#define SQUASHFS_MEMSET(s, d, n)	memset(d, 0, n);
48