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 24 static const unsigned char sn9c2028_sof_marker[5] = 25 { 0xff, 0xff, 0x00, 0xc4, 0xc4 }; 26 27 static 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