xbus.c

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//  Copyright (c) 2003-2021 Xsens Technologies B.V. or subsidiaries worldwide.
//  All rights reserved.
//  
//  Redistribution and use in source and binary forms, with or without modification,
//  are permitted provided that the following conditions are met:
//  
//  1.  Redistributions of source code must retain the above copyright notice,
//      this list of conditions, and the following disclaimer.
//  
//  2.  Redistributions in binary form must reproduce the above copyright notice,
//      this list of conditions, and the following disclaimer in the documentation
//      and/or other materials provided with the distribution.
//  
//  3.  Neither the names of the copyright holders nor the names of their contributors
//      may be used to endorse or promote products derived from this software without
//      specific prior written permission.
//  
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
//  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
//  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
//  THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
//  SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
//  OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
//  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR
//  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
//  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.THE LAWS OF THE NETHERLANDS 
//  SHALL BE EXCLUSIVELY APPLICABLE AND ANY DISPUTES SHALL BE FINALLY SETTLED UNDER THE RULES 
//  OF ARBITRATION OF THE INTERNATIONAL CHAMBER OF COMMERCE IN THE HAGUE BY ONE OR MORE 
//  ARBITRATORS APPOINTED IN ACCORDANCE WITH SAID RULES.
//  
 
 
//  Copyright (c) 2003-2021 Xsens Technologies B.V. or subsidiaries worldwide.
//  All rights reserved.
//  
//  Redistribution and use in source and binary forms, with or without modification,
//  are permitted provided that the following conditions are met:
//  
//  1.  Redistributions of source code must retain the above copyright notice,
//      this list of conditions, and the following disclaimer.
//  
//  2.  Redistributions in binary form must reproduce the above copyright notice,
//      this list of conditions, and the following disclaimer in the documentation
//      and/or other materials provided with the distribution.
//  
//  3.  Neither the names of the copyright holders nor the names of their contributors
//      may be used to endorse or promote products derived from this software without
//      specific prior written permission.
//  
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
//  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
//  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
//  THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
//  SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
//  OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
//  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR
//  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
//  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.THE LAWS OF THE NETHERLANDS 
//  SHALL BE EXCLUSIVELY APPLICABLE AND ANY DISPUTES SHALL BE FINALLY SETTLED UNDER THE RULES 
//  OF ARBITRATION OF THE INTERNATIONAL CHAMBER OF COMMERCE IN THE HAGUE BY ONE OR MORE 
//  ARBITRATORS APPOINTED IN ACCORDANCE WITH SAID RULES.
//  
 
#include "xbus.h"
 
 
bool Xbus_checkPreamble(const uint8_t* xbusMessage)
{
        return xbusMessage[OFFSET_TO_PREAMBLE] == XBUS_PREAMBLE;
}
 
int Xbus_getBusId(const uint8_t* xbusMessage)
{
        return (xbusMessage[OFFSET_TO_BID] & 0xff);
}
 
void Xbus_setBusId(uint8_t* xbusMessage, uint8_t busId)
{
        xbusMessage[OFFSET_TO_BID] = busId & 0xff;
}
 
int Xbus_getMessageId(const uint8_t* xbusMessage)
{
        return (xbusMessage[OFFSET_TO_MID] & 0xff);
}
 
void Xbus_setMessageId(uint8_t* xbusMessage, uint8_t messageId)
{
        xbusMessage[OFFSET_TO_MID] = messageId & 0xff;
}
 
int Xbus_getPayloadLength(const uint8_t* xbusMessage)
{
        int length = xbusMessage[OFFSET_TO_LEN] & 0xff;
        if (length != LENGTH_EXTENDER_BYTE)
                return length;
        else
        {
                int result = (xbusMessage[OFFSET_TO_LEN + 2] & 0xff);
                result += (xbusMessage[OFFSET_TO_LEN + 1] & 0xff) << 8;
                return result;
        }
}
 
void Xbus_setPayloadLength(uint8_t* xbusMessage, uint16_t payloadLength)
{
        if (payloadLength < 255)
                xbusMessage[OFFSET_TO_LEN] = payloadLength & 0xff;
        else
        {
                xbusMessage[OFFSET_TO_LEN] = LENGTH_EXTENDER_BYTE;
                xbusMessage[OFFSET_TO_LEN + 1] = (payloadLength >> 8) & 0xff;
                xbusMessage[OFFSET_TO_LEN + 2] = payloadLength & 0xff;
        }
}
 
void Xbus_message(uint8_t* xbusMessage, uint8_t bid, uint8_t mid, uint16_t len)
{
        xbusMessage[0] = 0xFA;
        Xbus_setBusId(xbusMessage, bid);
        Xbus_setMessageId(xbusMessage, mid);
        Xbus_setPayloadLength(xbusMessage, len);
}
 
int Xbus_getRawLength(const uint8_t* xbusMessage)
{
        int rtrn = Xbus_getPayloadLength(xbusMessage);
 
        if ((xbusMessage[OFFSET_TO_LEN] & 0xff) == LENGTH_EXTENDER_BYTE)
                rtrn += 7;
        else
                rtrn += 5;
        return rtrn;
}
 
uint8_t* Xbus_getPointerToPayload(uint8_t* xbusMessage)
{
        if ((xbusMessage[OFFSET_TO_LEN] & 0xff) == LENGTH_EXTENDER_BYTE)
                return xbusMessage + OFFSET_TO_PAYLOAD_EXT;
        else
                return xbusMessage + OFFSET_TO_PAYLOAD;
}
 
uint8_t const* Xbus_getConstPointerToPayload(uint8_t const* xbusMessage)
{
        return Xbus_getPointerToPayload((uint8_t*)xbusMessage);
}
 
 
void Xbus_insertChecksum(uint8_t* xbusMessage)
{
        int nBytes = Xbus_getRawLength(xbusMessage);
 
        uint8_t checksum = 0;
        for (int i = 0; i < nBytes - 2; i++)
                checksum -= xbusMessage[1 + i];
 
        xbusMessage[nBytes - 1] = checksum;
}
 
bool Xbus_verifyChecksum(const uint8_t* xbusMessage)
{
        int nBytes =  Xbus_getRawLength(xbusMessage);
        uint8_t checksum = 0;
        for (int n = 1; n < nBytes; n++)
                checksum += (xbusMessage[n] & 0xff);
        checksum &= 0xff;
        return (checksum == 0);
}