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flightgear/src/Navaids/navlist.cxx
david 7e1b599368 Patch from Melchior Franz:
When the loop starts, n.type is still undefined, so the while statement
depends on unitialized garbage. The input operator cares for the [End]
bracket anyway (returns if the first character is a '['). So it is safe
to check for it after reading the line and break if necessary.
2002-03-27 12:49:29 +00:00

153 lines
3.7 KiB
C++

// navaids.cxx -- navaids management class
//
// Written by Curtis Olson, started April 2000.
//
// Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/debug/logstream.hxx>
#include <simgear/misc/sgstream.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include "navlist.hxx"
FGNavList *current_navlist;
// Constructor
FGNavList::FGNavList( void ) {
}
// Destructor
FGNavList::~FGNavList( void ) {
}
// load the navaids and build the map
bool FGNavList::init( SGPath path ) {
FGNav n;
navaids.erase( navaids.begin(), navaids.end() );
sg_gzifstream in( path.str() );
if ( !in.is_open() ) {
SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << path.str() );
exit(-1);
}
// read in each line of the file
in >> skipeol;
in >> skipcomment;
#ifdef __MWERKS__
char c = 0;
while ( in.get(c) && c != '\0' && n.get_type() != '[' ) {
in.putback(c);
in >> n;
if ( n.get_type() != '[' ) {
navaids[n.get_freq()].push_back(n);
}
in >> skipcomment;
}
#else
double min = 100000;
double max = 0;
while ( ! in.eof() ) {
in >> n;
if ( n.get_type() == '[' ) {
break;
}
/* cout << "id = " << n.get_ident() << endl;
cout << " type = " << n.get_type() << endl;
cout << " lon = " << n.get_lon() << endl;
cout << " lat = " << n.get_lat() << endl;
cout << " elev = " << n.get_elev() << endl;
cout << " freq = " << n.get_freq() << endl;
cout << " range = " << n.get_range() << endl; */
navaids[n.get_freq()].push_back(n);
in >> skipcomment;
if ( n.get_type() != 'N' ) {
if ( n.get_freq() < min ) {
min = n.get_freq();
}
if ( n.get_freq() > max ) {
max = n.get_freq();
}
}
}
// cout << "min freq = " << min << endl;
// cout << "max freq = " << max << endl;
#endif
return true;
}
// query the database for the specified frequency, lon and lat are in
// degrees, elev is in meters
bool FGNavList::query( double lon, double lat, double elev, double freq,
FGNav *n )
{
nav_list_type stations = navaids[(int)(freq*100.0 + 0.5)];
nav_list_iterator current = stations.begin();
nav_list_iterator last = stations.end();
// double az1, az2, s;
Point3D aircraft = sgGeodToCart( Point3D(lon, lat, elev) );
Point3D station;
double d;
for ( ; current != last ; ++current ) {
// cout << "testing " << current->get_ident() << endl;
station = Point3D(current->get_x(), current->get_y(), current->get_z());
d = aircraft.distance3Dsquared( station );
// cout << " dist = " << sqrt(d)
// << " range = " << current->get_range() * SG_NM_TO_METER << endl;
// match up to twice the published range so we can model
// reduced signal strength
if ( d < (2 * current->get_range() * SG_NM_TO_METER
* 2 * current->get_range() * SG_NM_TO_METER ) ) {
// cout << "matched = " << current->get_ident() << endl;
*n = *current;
return true;
}
}
return false;
}