nmea_protocolhandler.cpp

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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 "nmea_protocolhandler.h"
#include "xscontrollerconfig.h"
 
namespace nmea
{
 
const char PREAMBLE = '$';
const char PREAMBLE_TSS2 = ':';
const char PREAMBLE_EM1000 = '\0';
const unsigned char AFTER_PREAMBLE_EM1000 = 0x90;
const char CR = '\r';
const char LF = '\n';
 
ProtocolHandler::ProtocolHandler()
{
}
 
ProtocolHandler::~ProtocolHandler() throw()
{
}
 
MessageLocation ProtocolHandler::findMessage(XsProtocolType& type, const XsByteArray& raw) const
{
        type = XPT_Nmea;
        MessageLocation location(-1, 0, -1, 0);
 
        int bufferSize = (int)raw.size();
        if (bufferSize == 0)
                return location;
 
        const unsigned char* buffer = raw.data();
 
        bool foundPreamble = false;
        bool foundEnd = false;
        int start = 0;
        int end = 0;
        for (int i = 0; i < bufferSize; i++)
        {
                if (!foundPreamble)
                {
                        if ((buffer[i] == PREAMBLE) || (buffer[i] == PREAMBLE_TSS2) || (buffer[i] == PREAMBLE_EM1000))
                        {
                                foundPreamble = true;
                                start = i;
                        }
                }
                if (foundPreamble)
                {
                        if ((buffer[i] == LF) && (buffer[i - 1] == CR))
                        {
                                foundEnd = true;
                                end = i + 1;
                        }
                        else if ((buffer[i] == AFTER_PREAMBLE_EM1000) && (buffer[i - 1] == PREAMBLE_EM1000)) // special case EM1000
                        {
                                if ((i - start) == 1 && (i + 9) < bufferSize)
                                {
                                        foundEnd = true;
                                        end = i + 9;
                                }
                                else
                                        foundPreamble = false;
                        }
                }
                if (foundPreamble && foundEnd)
                        break;
        }
 
        location.m_startPos = start;
        location.m_size = end - start;
 
        return location;
}
 
XsMessage ProtocolHandler::convertToMessage(MessageLocation& location, const XsByteArray& raw) const
{
        (void)location;
        (void)raw;
        return XsMessage();
}
 
int ProtocolHandler::minimumMessageSize() const
{
        return MINIMUM_MESSAGE_SIZE;
}
 
int ProtocolHandler::maximumMessageSize() const
{
        return MAXIMUM_MESSAGE_SIZE;
}
 
int ProtocolHandler::type() const
{
        return XPT_Nmea;
}
 
}