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Annotation of libaitcrc/src/pelco.c, revision 1.2.4.1

1.2       misho       1: /*************************************************************************
                      2: * (C) 2010 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
                      3: *  by Michael Pounov <misho@openbsd-bg.org>
                      4: *
                      5: * $Author: misho $
1.2.4.1 ! misho       6: * $Id: pelco.c,v 1.2 2010/01/20 00:15:06 misho Exp $
1.2       misho       7: *
1.2.4.1 ! misho       8: **************************************************************************
        !             9: The ELWIX and AITNET software is distributed under the following
        !            10: terms:
        !            11: 
        !            12: All of the documentation and software included in the ELWIX and AITNET
        !            13: Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
        !            14: 
        !            15: Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
        !            16:        by Michael Pounov <misho@elwix.org>.  All rights reserved.
        !            17: 
        !            18: Redistribution and use in source and binary forms, with or without
        !            19: modification, are permitted provided that the following conditions
        !            20: are met:
        !            21: 1. Redistributions of source code must retain the above copyright
        !            22:    notice, this list of conditions and the following disclaimer.
        !            23: 2. Redistributions in binary form must reproduce the above copyright
        !            24:    notice, this list of conditions and the following disclaimer in the
        !            25:    documentation and/or other materials provided with the distribution.
        !            26: 3. All advertising materials mentioning features or use of this software
        !            27:    must display the following acknowledgement:
        !            28: This product includes software developed by Michael Pounov <misho@elwix.org>
        !            29: ELWIX - Embedded LightWeight unIX and its contributors.
        !            30: 4. Neither the name of AITNET nor the names of its contributors
        !            31:    may be used to endorse or promote products derived from this software
        !            32:    without specific prior written permission.
        !            33: 
        !            34: THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
        !            35: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            36: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            37: ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            38: FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            39: DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            40: OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            41: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            42: LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            43: OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            44: SUCH DAMAGE.
        !            45: */
1.2       misho      46: #include "global.h"
                     47: 
                     48: 
                     49: /*
                     50:  * crcPelco() Calculate Pelco D/P CRC
                     51:  * @ver = Pelco protocol version (Dd | Pp)
                     52:  * @pkt = Packet for calculate crc
                     53:  * return: crc for packet, if is 0 check and crc_GetErrno() == 1 
                     54:        Pelco protocol not supported
                     55:  */
                     56: inline u_char crcPelco(u_char ver, u_char *pkt)
                     57: {
                     58:        register u_char i, crc;
                     59: 
                     60:        switch (ver) {
                     61:                case 'D':
                     62:                case 'd':
                     63:                        for (i = 1, crc = 0; i < 6; crc += pkt[i++]);
                     64:                        crc %= 0x100;
                     65:                        break;
                     66:                case 'P':
                     67:                case 'p':
                     68:                        for (i = 1, crc = pkt[0]; i < 7; crc ^= pkt[i++]);
                     69:                        break;
                     70:                default:
                     71:                        crc = 0;
                     72:                        crcSetErr(1, "crcAdler(): Invalid parameters!");
                     73:        }
                     74: 
                     75:        return crc;
                     76: }