CNavEmptyFilter.cpp

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//==============================================================================
//
//  This file is part of GNSSTk, the ARL:UT GNSS Toolkit.
//
//  The GNSSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 3.0 of the License, or
//  any later version.
//
//  The GNSSTk is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GNSSTk; if not, write to the Free Software Foundation,
//  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
//
//  This software was developed by Applied Research Laboratories at the
//  University of Texas at Austin.
//  Copyright 2004-2022, The Board of Regents of The University of Texas System
//
//==============================================================================
 
//==============================================================================
//
//  This software was developed by Applied Research Laboratories at the
//  University of Texas at Austin, under contract to an agency or agencies
//  within the U.S. Department of Defense. The U.S. Government retains all
//  rights to use, duplicate, distribute, disclose, or release this software.
//
//  Pursuant to DoD Directive 523024
//
//  DISTRIBUTION STATEMENT A: This software has been approved for public
//                            release, distribution is unlimited.
//
//==============================================================================
 
#include "CNavFilterData.hpp"
#include "CNavEmptyFilter.hpp"
 
namespace gnsstk
{
   CNavEmptyFilter ::
   CNavEmptyFilter()
   {
   }
 
      // Bits 39-276 are a total of 238 bits.   That's 7 * 32 with
      // a remainder of 14.
   void CNavEmptyFilter ::
   validate(NavMsgList& msgBitsIn, NavMsgList& msgBitsOut)
   {
      unsigned long word[8];
 
      NavMsgList::const_iterator i;
      for (i = msgBitsIn.begin(); i != msgBitsIn.end(); i++)
      {
         CNavFilterData *fd = dynamic_cast<CNavFilterData*>(*i);
 
         int startBit = 38;
         for (int n=0;n<7;n++)
         {
            word[n] = fd->pnb->asUnsignedLong(startBit,32,1);
            startBit += 32;
         }
         word[7] = fd->pnb->asUnsignedLong(startBit,14,1);
 
         bool blank =
            ( (word[0]==0) &&
              (word[1]==0) &&
              (word[2]==0) &&
              (word[3]==0) &&
              (word[4]==0) &&
              (word[5]==0) &&
              (word[6]==0) &&
              (word[7]==0) ) ||
 
            ( (word[0]==0x55555555) &&
              (word[1]==0x55555555) &&
              (word[2]==0x55555555) &&
              (word[3]==0x55555555) &&
              (word[4]==0x55555555) &&
              (word[5]==0x55555555) &&
              (word[6]==0x55555555) &&
              (word[7]==0x00001555) ) /*||
 
            ( (word[0]==0xAAAAAAAA) &&         This is valid for default nav
              (word[1]==0xAAAAAAAA) &&
              (word[2]==0xAAAAAAAA) &&
              (word[3]==0xAAAAAAAA) &&
              (word[4]==0xAAAAAAAA) &&
              (word[5]==0xAAAAAAAA) &&
              (word[6]==0xAAAAAAAA) &&
              (word[7]==0x00002AAA) ) */;
 
         if (blank)
            reject(fd);
         else
            accept(fd, msgBitsOut);
      }
   }
}