source: pacpussensors/trunk/NMEA0183/src/HDG.cpp

#include "nmea0183.h"
#pragma hdrstop

/*
** Author: Samuel R. Blackburn
** Internet: sam_blackburn@pobox.com
**
** You can use it any way you like as long as you don't try to sell it.
**
** Copyright, 1996, Samuel R. Blackburn
**
** $Workfile: hdg.cpp $
** $Revision: 4 $
** $Modtime: 10/10/98 2:44p $
*/


HDG::HDG()
{
   Mnemonic = "HDG";
   Empty();
}

HDG::~HDG()
{
   //Mnemonic.Empty();
   Empty();
}

void HDG::Empty( void )
{
   MagneticSensorHeadingDegrees = 0.0;
   MagneticDeviationDegrees     = 0.0;
   MagneticDeviationDirection   = EW_Unknown;
   MagneticVariationDegrees     = 0.0;
   MagneticVariationDirection   = EW_Unknown;
}

BOOL HDG::Parse( const SENTENCE& sentence )
{
   /*
   ** HDG - Heading - Deviation & Variation
   **
   **        1   2   3 4   5 6
   **        |   |   | |   | |
   ** $--HDG,x.x,x.x,a,x.x,a*hh<CR><LF>
   **
   ** Field Number: 
   **  1) Magnetic Sensor heading in degrees
   **  2) Magnetic Deviation, degrees
   **  3) Magnetic Deviation direction, E = Easterly, W = Westerly
   **  4) Magnetic Variation degrees
   **  5) Magnetic Variation direction, E = Easterly, W = Westerly
   **  6) Checksum
   */

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

   if ( sentence.IsChecksumBad( 6 ) == True )
   {
      SetErrorMessage( "Invalid Checksum" );
      return( FALSE );
   } 

   MagneticSensorHeadingDegrees = sentence.Double( 1 );
   MagneticDeviationDegrees     = sentence.Double( 2 );
   MagneticDeviationDirection   = sentence.EastOrWest( 3 );
   MagneticVariationDegrees     = sentence.Double( 4 );
   MagneticVariationDirection   = sentence.EastOrWest( 5 );

   return( TRUE );
}

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

   sentence += MagneticSensorHeadingDegrees;
   sentence += MagneticDeviationDegrees;
   sentence += MagneticDeviationDirection;
   sentence += MagneticVariationDegrees;
   sentence += MagneticVariationDirection;

   sentence.Finish();

   return( TRUE );
}

const HDG& HDG::operator = ( const HDG& source )
{
   MagneticSensorHeadingDegrees = source.MagneticSensorHeadingDegrees;
   MagneticDeviationDegrees     = source.MagneticDeviationDegrees;
   MagneticDeviationDirection   = source.MagneticDeviationDirection;
   MagneticVariationDegrees     = source.MagneticVariationDegrees;
   MagneticVariationDirection   = source.MagneticVariationDirection;

   return( *this );
}