sfi.cpp

来自「提取各种NEMA0183格式数据的类编程。」· C++ 代码 · 共 182 行

/*
** Author: Samuel R. Blackburn
** Internet: [e-mail]
**
** Copyright, 1996-2005, 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: sfi.cpp $
** $Revision: 4 $
** $Modtime: 10/10/98 2:37p $
*/

#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

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

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

void SFI::Empty( void )
{
   TotalMessages = 0.0;
   MessageNumber = 0.0;

   int index = 0;

   while( index < 6 )
   {
      Frequencies[ index ].Empty();
      index++;
   }

}

BOOL SFI::Parse( const SENTENCE& sentence )
{
   /*
   ** SFI - Scanning Frequency Information
   **
   **        1   2   3      4                     x
   **        |   |   |      |                     |
   ** $--SFI,x.x,x.x,xxxxxx,c .......... xxxxxx,c*hh<CR><LF>
   **
   **  1) Total Number Of Messages
   **  2) Message Number
   **  3) Frequency 1
   **  4) Mode 1
   **  x) Checksum
   */

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

   int number_of_data_fields = sentence.GetNumberOfDataFields();

   const NMEA0183_BOOLEAN checksum_is_bad = sentence.IsChecksumBad();

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

   TotalMessages = sentence.Double( 1 );
   MessageNumber = sentence.Double( 2 );

   /*
   ** Clear out any old data
   */

   int index = 0;

   while( index < 6 )
   {
      Frequencies[ index ].Empty();
      index++;
   }

   int number_of_frequencies = ( number_of_data_fields - 2 ) / 2;
   int frequency_number      = 0;

   /*
   ** index is the number of data fields before the frequency/mode +
   ** the frequency number times the number of fields in a FREQUENC_AND_MODE
   */

   while( frequency_number < number_of_frequencies )
   {
      index = 2 + ( frequency_number * 2 );

      Frequencies[ frequency_number ].Parse( index, sentence );

      frequency_number++;
   }

   return( TRUE );
}

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

   sentence += TotalMessages;
   sentence += MessageNumber;

   int index = 0;

   while( index < 6 )
   {
      Frequencies[ index ].Write( sentence );
      index++;
   }

   sentence.Finish();

   return( TRUE );
}

const SFI& SFI::operator = ( const SFI& source )
{
   TotalMessages = source.TotalMessages;
   MessageNumber = source.MessageNumber;

   int index = 0;

   while( index < 6 )
   {
      Frequencies[ index ] = source.Frequencies[ index ];
      index++;
   }

   return( *this );
}