1/*
2 * SN9C2028 common functions
3 *
4 * Copyright (C) 2009 Theodore Kilgore <kilgota@auburn,edu>
5 *
6 * Based closely upon the file gspca/pac_common.h
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (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, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21 *
22 */
23
24static const unsigned char sn9c2028_sof_marker[5] =
25	{ 0xff, 0xff, 0x00, 0xc4, 0xc4 };
26
27static unsigned char *sn9c2028_find_sof(struct gspca_dev *gspca_dev,
28					unsigned char *m, int len)
29{
30	struct sd *sd = (struct sd *) gspca_dev;
31	int i;
32
33	/* Search for the SOF marker (fixed part) in the header */
34	for (i = 0; i < len; i++) {
35		if (m[i] == sn9c2028_sof_marker[sd->sof_read]) {
36			sd->sof_read++;
37			if (sd->sof_read == sizeof(sn9c2028_sof_marker)) {
38				PDEBUG(D_FRAM,
39					"SOF found, bytes to analyze: %u."
40					" Frame starts at byte #%u",
41					len, i + 1);
42				sd->sof_read = 0;
43				return m + i + 1;
44			}
45		} else {
46			sd->sof_read = 0;
47		}
48	}
49
50	return NULL;
51}
52