vwt.cpp

提取各种NEMA0183格式数据的类编程。

/*
** Author: Samuel R. Blackburn
** Internet: [e-mail]
**
** Copyright, 2005, Samuel R. Blackburn
**
** "You can get credit for something or get it done, but not both."
** Dr. Richard Garwin
**
** BSD License follows.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** Redistributions of source code must retain the above copyright notice,
** this list of conditions and the following disclaimer. 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. Neither the name of
** the WFC nor the names of its 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
** OWNER 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.
**
** $Workfile: VWT.cpp $
** $Revision: 4 $
** $Modtime: 10/10/98 2:42p $
*/

#include "nmea0183.h"
#pragma hdrstop

#if defined( _DEBUG ) && defined( _INC_CRTDBG )
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#define new DEBUG_NEW
#endif // _DEBUG

VWT::VWT()
{
   Mnemonic = TEXT( "VWT" );
   Empty();
}

VWT::~VWT()
{
   Mnemonic.Empty();
   Empty();
}

void VWT::Empty( void )
{
   CalculatedWindAngle                  = 0.0;
   CalculatedDirection                  = LR_Unknown;
   CalculatedWindSpeedKnots             = 0.0;
   CalculatedWindSpeedMetersPerSecond   = 0.0;
   CalculatedWindSpeedKilometersPerHour = 0.0;
}

BOOL VWT::Parse( const SENTENCE& sentence )
{
   /*
   ** VWT - True Wind Speed and Angle
   **
   **        1   2 3   4 5   6 7   8 9
   **        |   | |   | |   | |   | |
   ** $--VWT,x.x,a,x.x,N,x.x,M,x.x,K*hh<CR><LF>
   **
   ** Field Number: 
   **  1) Calculated Wind Angle in relation to the boat, 0 to 180 degrees
   **  2) Left or Right
   **  3) Calculated wind speed in knots
   **  4) N = Knots
   **  5) Calculated wind speed in meters per second
   **  6) M = Meters per second
   **  7) Calculated wind speed in kilometers per hour
   **  8) K = Kilometers per hour
   **  9) Checksum
   */

   /*
   ** First we check the checksum...
   */

   const NMEA0183_BOOLEAN checksum_is_bad = sentence.IsChecksumBad();

   if ( checksum_is_bad == True )
   {
      InvalidChecksum();
      return( FALSE );
   }

   CalculatedWindAngle                  = sentence.Double( 1 );
   CalculatedDirection                  = sentence.LeftOrRight( 2 );
   CalculatedWindSpeedKnots             = sentence.Double( 3 );
   CalculatedWindSpeedMetersPerSecond   = sentence.Double( 5 );
   CalculatedWindSpeedKilometersPerHour = sentence.Double( 7 );

   return( TRUE );
}

BOOL VWT::Write( SENTENCE& sentence )
{
   /*
   ** Let the parent do its thing
   */
   
   RESPONSE::Write( sentence );

   sentence += CalculatedWindAngle;
   sentence += CalculatedDirection;
   sentence += CalculatedWindSpeedKnots;
   sentence += "N";
   sentence += CalculatedWindSpeedMetersPerSecond;
   sentence += "M";
   sentence += CalculatedWindSpeedKilometersPerHour;
   sentence += "K";

   sentence.Finish();

   return( TRUE );
}

const VWT& VWT::operator = ( const VWT& source )
{
   CalculatedWindAngle                  = source.CalculatedWindAngle;
   CalculatedDirection                  = source.CalculatedDirection;
   CalculatedWindSpeedKnots             = source.CalculatedWindSpeedKnots;
   CalculatedWindSpeedMetersPerSecond   = source.CalculatedWindSpeedMetersPerSecond;
   CalculatedWindSpeedKilometersPerHour = source.CalculatedWindSpeedKilometersPerHour;

   return( *this );
}