apt_loader.cxx

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/*
 * SPDX-FileName: apt_loader.cxx
 * SPDX-FileComment: a front end loader of the apt.dat file.  This loader populates the runway and basic classes.
 * SPDX-FileCopyrightText: Copyright (C) 2004  Curtis L. Olson  - http://www.flightgear.org/~curt
 * SPDX-License-Identifier: GPL-2.0-or-later
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
#include <algorithm>
#include <cerrno>
#include <cstddef>  // std::size_t
#include <ctype.h>  // isspace()
#include <iostream>
#include <sstream>  // std::istringstream
#include <stdlib.h> // atof(), atoi()
#include <string.h> // memchr()
#include <string>
#include <utility>  // std::pair, std::move()
#include <vector>
 
#include <simgear/compiler.h>
#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/io/iostreams/sgstream.hxx>
#include <simgear/misc/sg_path.hxx>
#include <simgear/misc/strutils.hxx>
#include <simgear/structure/exception.hxx>
 
#include <ATC/CommStation.hxx>
#include <Navaids/NavDataCache.hxx>
#include <Navaids/positioned.hxx>
 
#include "airport.hxx"
#include "apt_loader.hxx"
#include "pavement.hxx"
#include "runways.hxx"
 
 
using std::string;
using std::vector;
 
namespace strutils = simgear::strutils;
 
 
static FGPositioned::Type fptypeFromRobinType(unsigned int aType)
{
    switch (aType) {
    case 1: return FGPositioned::AIRPORT;
    case 16: return FGPositioned::SEAPORT;
    case 17: return FGPositioned::HELIPORT;
    default:
        SG_LOG(SG_GENERAL, SG_ALERT, "unsupported type:" << aType);
        throw sg_range_exception("Unsupported airport type", "fptypeFromRobinType");
    }
}
 
namespace flightgear {
APTLoader::APTLoader()
    : last_apt_id(""),
      last_apt_elev(0.0),
      currentAirportPosID(0),
      cache(NavDataCache::instance())
{
}
 
APTLoader::~APTLoader() {}
 
void APTLoader::readAptDatFile(const NavDataCache::SceneryLocation& sceneryLocation,
                               std::size_t bytesReadSoFar,
                               std::size_t totalSizeOfAllAptDatFiles)
{
    const SGPath aptdb_file = sceneryLocation.datPath;
    string apt_dat = aptdb_file.utf8Str(); // full path to the file being parsed
    sg_gzifstream in(aptdb_file, std::ios_base::in | std::ios_base::binary, true);
 
    if (!in.is_open()) {
        const std::string errMsg = simgear::strutils::error_string(errno);
        SG_LOG(SG_GENERAL, SG_ALERT,
               "Cannot open file '" << apt_dat << "': " << errMsg);
        throw sg_io_exception("Cannot open file (" + errMsg + ")",
                              sg_location(aptdb_file));
    }
 
    string line;
 
    unsigned int rowCode = 0; // terminology used in the apt.dat format spec
    unsigned int line_num = 0;
    // "airport identifier": terminology used in the apt.dat format spec. It is
    // often an ICAO code, but not always.
    string currentAirportId;
    // Boolean used to make sure we don't try to load the same airport several
    // times. Defaults to true only to ensure we don't add garbage to
    // 'airportInfoMap' under the key "" (empty airport identifier) in case the
    // apt.dat file doesn't have a start-of-airport row code (1, 16 or 17) after
    // its header---which would be invalid, anyway.
    bool skipAirport = true;
 
    // Read the apt.dat header (two lines)
    while (line_num < 2 && std::getline(in, line)) {
        // 'line' may end with an \r character (tested on Linux, only \n was
        // stripped: std::getline() only discards the _native_ line terminator)
        line_num++;
 
        if (line_num == 1) {
            std::string stripped_line = simgear::strutils::strip(line);
            // First line indicates IBM ("I") or Macintosh ("A") line endings.
            if (stripped_line != "I" && stripped_line != "A") {
                std::string pb = "invalid first line (neither 'I' nor 'A')";
                SG_LOG(SG_GENERAL, SG_ALERT, aptdb_file << ": " << pb);
                throw sg_format_exception("cannot parse '" + apt_dat + "': " + pb,
                                          stripped_line);
            }
        } else { // second line of the file
            vector<string> fields(strutils::split(line, 0, 1));
 
            if (fields.empty()) {
                string errMsg = "unable to parse format version: empty line";
                SG_LOG(SG_GENERAL, SG_ALERT, apt_dat << ": " << errMsg);
                throw sg_format_exception("cannot parse '" + apt_dat + "': " + errMsg,
                                          string());
            } else {
                unsigned int aptDatFormatVersion =
                    strutils::readNonNegativeInt<unsigned int>(fields[0]);
                SG_LOG(SG_GENERAL, SG_INFO,
                       "apt.dat format version (" << apt_dat << "): " << aptDatFormatVersion);
            }
        }
    } // end of the apt.dat header
 
    throwExceptionIfStreamError(in, aptdb_file);
 
    while (std::getline(in, line)) {
        // 'line' may end with an \r character, see above
        line_num++;
 
        if (isBlankOrCommentLine(line))
            continue;
 
        if ((line_num % 100) == 0) {
            // every 100 lines
            unsigned int percent = ((bytesReadSoFar + in.approxOffset()) * 100) / totalSizeOfAllAptDatFiles;
            cache->setRebuildPhaseProgress(
                NavDataCache::REBUILD_READING_APT_DAT_FILES, percent);
        }
 
        // Extract the first field into 'rowCode'
        rowCode = atoi(line.c_str());
 
        if (rowCode == 1 /* Airport */ ||
            rowCode == 16 /* Seaplane base */ ||
            rowCode == 17 /* Heliport */) {
            vector<string> tokens(simgear::strutils::split(line));
            if (tokens.size() < 6) {
                SG_LOG(SG_GENERAL, SG_WARN,
                       apt_dat << ":" << line_num << ": invalid airport header "
                                                     "(at least 6 fields are required)");
                skipAirport = true; // discard everything until the next airport header
                continue;
            }
 
            currentAirportId = tokens[4]; // often an ICAO, but not always
            // Check if the airport is already in 'airportInfoMap'; get the
            // existing entry, if any, otherwise insert a new one.
            std::pair<AirportInfoMapType::iterator, bool>
                insertRetval = airportInfoMap.insert(
                    AirportInfoMapType::value_type(currentAirportId, RawAirportInfo()));
            skipAirport = !insertRetval.second;
 
            if (skipAirport) {
                SG_LOG(SG_GENERAL, SG_INFO,
                       apt_dat << ":" << line_num << ": skipping airport " << currentAirportId << " (already defined earlier)");
            } else {
                // We haven't seen this airport yet in any apt.dat file
                RawAirportInfo& airportInfo = insertRetval.first->second;
                airportInfo.file = aptdb_file;
                airportInfo.sceneryPath = sceneryLocation.sceneryPath;
                airportInfo.rowCode = rowCode;
                airportInfo.firstLineNum = line_num;
                airportInfo.firstLineTokens = std::move(tokens);
            }
        } else if (rowCode == 99) {
            SG_LOG(SG_GENERAL, SG_DEBUG,
                   apt_dat << ":" << line_num << ": code 99 found "
                                                 "(normally at end of file)");
        } else if (!skipAirport) {
            // Line belonging to an already started, and not skipped airport entry;
            // just append it.
            airportInfoMap[currentAirportId].otherLines.emplace_back(
                line_num, rowCode, line);
        }
    } // of file reading loop
 
    throwExceptionIfStreamError(in, aptdb_file);
}
 
void APTLoader::loadAirports()
{
    AirportInfoMapType::size_type nbLoadedAirports = 0;
    AirportInfoMapType::size_type nbAirports = airportInfoMap.size();
 
    // Loop over all airports found in all apt.dat files
    for (AirportInfoMapType::const_iterator it = airportInfoMap.begin();
         it != airportInfoMap.end(); ++it) {
        // Full path to the apt.dat file this airport info comes from
        const SGPath aptDat = it->second.file;
 
        // this is just the current airport identifier
        last_apt_id = it->first;
        RawAirportInfo rawinfo = it->second;
 
        loadAirport(aptDat, last_apt_id, &rawinfo);
        nbLoadedAirports++;
 
        if ((nbLoadedAirports % 300) == 0) {
            // Every 300 airports
            unsigned int percent = nbLoadedAirports * 100 / nbAirports;
            cache->setRebuildPhaseProgress(NavDataCache::REBUILD_LOADING_AIRPORTS,
                                           percent);
        }
    } // of loop over 'airportInfoMap'
 
    SG_LOG(SG_GENERAL, SG_INFO,
           "Loaded data for " << nbLoadedAirports << " airports");
}
 
// Parse and return specific apt.dat file containing a single airport.
const FGAirport* APTLoader::loadAirportFromFile(const std::string& id, const NavDataCache::SceneryLocation& sceneryLocation)
{
    std::size_t bytesReadSoFar = 10;
    std::size_t totalSizeOfAllAptDatFiles = 100;
 
    readAptDatFile(sceneryLocation, bytesReadSoFar, totalSizeOfAllAptDatFiles);
 
    RawAirportInfo rawInfo = airportInfoMap[id];
    return loadAirport(sceneryLocation.datPath, id, &rawInfo, true);
}
 
static bool isCommLine(const int code)
{
    return ((code >= 50) && (code <= 56)) || ((code >= 1050) && (code <= 1056));
}
 
const FGAirport* APTLoader::loadAirport(const SGPath& aptDatFile, const std::string& airportID, RawAirportInfo* airport_info, bool createFGAirport)
{
    // The first line for this airport was already split over whitespace, but
    // remains to be parsed for the most part.
    parseAirportLine(airport_info->rowCode, airport_info->firstLineTokens,
                     airport_info->sceneryPath);
    const LinesList& lines = airport_info->otherLines;
 
    const string aptDat = aptDatFile.utf8Str();
    NodeBlock current_block = None;
 
    // Loop over the second and subsequent lines
    for (LinesList::const_iterator linesIt = lines.begin();
         linesIt != lines.end(); ++linesIt) {
        // Beware that linesIt->str may end with an '\r' character, see above!
        unsigned int rowCode = linesIt->rowCode;
 
        if (rowCode == 10) { // Runway v810
            parseRunwayLine810(aptDat, linesIt->number,
                               simgear::strutils::split(linesIt->str));
        } else if (rowCode == 100) { // Runway v850
            parseRunwayLine850(aptDat, linesIt->number,
                               simgear::strutils::split(linesIt->str));
        } else if (rowCode == 101) { // Water Runway v850
            parseWaterRunwayLine850(aptDat, linesIt->number,
                                    simgear::strutils::split(linesIt->str));
        } else if (rowCode == 102) { // Helipad v850
            parseHelipadLine850(aptDat, linesIt->number,
                                simgear::strutils::split(linesIt->str));
        } else if (rowCode == 18) {
            // beacon entry (ignore)
        } else if (rowCode == 14) { // Viewpoint/control tower
            parseViewpointLine(aptDat, linesIt->number,
                               simgear::strutils::split(linesIt->str));
        } else if (rowCode == 19) {
            // windsock entry (ignore)
        } else if (rowCode == 20) {
            // Taxiway sign (ignore)
        } else if (rowCode == 21) {
            // lighting objects (ignore)
        } else if (rowCode == 15) {
            // custom startup locations (ignore)
        } else if (rowCode == 0) {
            // ??
        } else if (isCommLine(rowCode)) {
            parseCommLine(aptDat, linesIt->number, rowCode,
                          simgear::strutils::split(linesIt->str));
        } else if (rowCode == 110) {
            current_block = Pavement;
            parsePavementLine850(simgear::strutils::split(linesIt->str, 0, 4));
        } else if (rowCode >= 111 && rowCode <= 116) {
            switch (current_block) {
            case Pavement:
                parseNodeLine850(&pavements, aptDat, linesIt->number, rowCode,
                                 simgear::strutils::split(linesIt->str));
                break;
            case AirportBoundary:
                parseNodeLine850(&airport_boundary, aptDat, linesIt->number, rowCode,
                                 simgear::strutils::split(linesIt->str));
                break;
            case LinearFeature:
                parseNodeLine850(&linear_feature, aptDat, linesIt->number, rowCode,
                                 simgear::strutils::split(linesIt->str));
                break;
            default:
            case None:
                std::ostringstream oss;
                string cleanedLine = cleanLine(linesIt->str);
                oss << aptDat << ":" << linesIt->number << ": unexpected row code " << rowCode;
                SG_LOG(SG_GENERAL, SG_ALERT, oss.str() << " (" << cleanedLine << ")");
                throw sg_format_exception(oss.str(), cleanedLine);
                break;
            }
        } else if (rowCode == 120) {
            current_block = LinearFeature;
        } else if (rowCode == 130) {
            current_block = AirportBoundary;
        } else if (rowCode >= 1000) {
            // airport traffic flow (ignore)
        } else {
            std::ostringstream oss;
            string cleanedLine = cleanLine(linesIt->str);
            oss << aptDat << ":" << linesIt->number << ": unknown row code " << rowCode;
            SG_LOG(SG_GENERAL, SG_DEV_ALERT, oss.str() << " (" << cleanedLine << ")");
        }
    } // of loop over the second and subsequent apt.dat lines for the airport
 
    finishAirport(aptDat);
 
    if (createFGAirport) {
        FGAirportRef airport = FGAirport::findByIdent(airportID);
 
        std::for_each(
            pavements.begin(),
            pavements.end(),
            [airport](FGPavementRef p) { airport->addPavement(p); });
 
        std::for_each(
            airport_boundary.begin(),
            airport_boundary.end(),
            [airport](FGPavementRef p) { airport->addBoundary(p); });
 
        std::for_each(
            linear_feature.begin(),
            linear_feature.end(),
            [airport](FGPavementRef p) { airport->addLineFeature(p); });
 
        pavements.clear();
        airport_boundary.clear();
        linear_feature.clear();
 
 
        return airport;
 
    } else {
        // No FGAirport requested
        return NULL;
    }
}
 
 
// Tell whether an apt.dat line is blank or a comment line
bool APTLoader::isBlankOrCommentLine(const std::string& line)
{
    size_t pos = line.find_first_not_of(" \t");
    return (pos == std::string::npos ||
            line[pos] == '\r' ||
            line.find("##", pos) == pos);
}
 
std::string APTLoader::cleanLine(const std::string& line)
{
    std::string res = line;
 
    // Lines obtained from readAptDatFile() may end with \r, which can be quite
    // confusing when printed to the terminal.
    for (std::string::reverse_iterator it = res.rbegin();
         it != res.rend() && *it == '\r';
         /* empty */) { // The beauty of C++ iterators...
        it = std::string::reverse_iterator(res.erase((it + 1).base()));
    }
 
    return res;
}
 
void APTLoader::throwExceptionIfStreamError(const sg_gzifstream& input_stream,
                                            const SGPath& path)
{
    if (input_stream.bad()) {
        const std::string errMsg = simgear::strutils::error_string(errno);
 
        SG_LOG(SG_NAVAID, SG_ALERT,
               "Error while reading '" << path.utf8Str() << "': " << errMsg);
        throw sg_io_exception("APTLoader: error reading file (" + errMsg + ")",
                              sg_location(path));
    }
}
 
void APTLoader::finishAirport(const string& aptDat)
{
    if (currentAirportPosID == 0) {
        return;
    }
 
    if (!rwy_count) {
        currentAirportPosID = 0;
        SG_LOG(SG_GENERAL, SG_ALERT, "Error in '" << aptDat << "': no runways for " << last_apt_id << ", skipping.");
        return;
    }
 
    double lat = rwy_lat_accum / (double)rwy_count;
    double lon = rwy_lon_accum / (double)rwy_count;
 
    SGGeod pos(SGGeod::fromDegFt(lon, lat, last_apt_elev));
    cache->updatePosition(currentAirportPosID, pos);
 
    currentAirportPosID = 0;
}
 
// 'rowCode' is passed to avoid decoding it twice, since that work was already
// done in order to detect the start of the new airport.
void APTLoader::parseAirportLine(unsigned int rowCode,
                                 const vector<string>& token,
                                 const SGPath& sceneryPath)
{
    // The algorithm in APTLoader::readAptDatFile() ensures this is at least 5.
    vector<string>::size_type lastIndex = token.size() - 1;
    const string& id(token[4]);
    double elev = atof(token[1].c_str());
    last_apt_elev = elev;
 
    string name;
    // build the name
    for (vector<string>::size_type i = 5; i < lastIndex; ++i) {
        name += token[i] + " ";
    }
    name += token[lastIndex];
 
    // clear runway list for start of next airport
    rwy_lon_accum = 0.0;
    rwy_lat_accum = 0.0;
    rwy_count = 0;
 
    currentAirportPosID = cache->insertAirport(fptypeFromRobinType(rowCode),
                                               id, name, sceneryPath);
}
 
void APTLoader::parseRunwayLine810(const string& aptDat, unsigned int lineNum,
                                   const vector<string>& token)
{
    if (token.size() < 11) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid v810 runway line "
                      << "(row code 10): at least 11 fields are required");
        return;
    }
 
    double lat = atof(token[1].c_str());
    double lon = atof(token[2].c_str());
    rwy_lat_accum += lat;
    rwy_lon_accum += lon;
    rwy_count++;
 
    const string& rwy_no(token[3]);
 
    double heading = atof(token[4].c_str());
    double length = atoi(token[5].c_str());
    double width = atoi(token[8].c_str());
    length *= SG_FEET_TO_METER;
    width *= SG_FEET_TO_METER;
 
    // adjust lat / lon to the start of the runway/taxiway, not the middle
    SGGeod pos_1 = SGGeodesy::direct(SGGeod::fromDegFt(lon, lat, last_apt_elev),
                                     heading, -length / 2);
 
    last_rwy_heading = heading;
 
    int surface_code = atoi(token[10].c_str());
 
    if (rwy_no[0] == 'x') { // Taxiway
        cache->insertRunway(
            FGPositioned::TAXIWAY, rwy_no, pos_1, currentAirportPosID,
            heading, length, width, 0.0, 0.0, surface_code);
    } else if (rwy_no[0] == 'H') { // Helipad
        SGGeod pos(SGGeod::fromDegFt(lon, lat, last_apt_elev));
        cache->insertRunway(FGPositioned::HELIPAD, rwy_no, pos, currentAirportPosID,
                            heading, length, width, 0.0, 0.0, surface_code);
    } else {
        // (pair of) runways
        string rwy_displ_threshold = token[6];
        vector<string> displ = simgear::strutils::split(rwy_displ_threshold, ".");
        double displ_thresh1 = atof(displ[0].c_str());
        double displ_thresh2 = atof(displ[1].c_str());
        displ_thresh1 *= SG_FEET_TO_METER;
        displ_thresh2 *= SG_FEET_TO_METER;
 
        string rwy_stopway = token[7];
        vector<string> stop = simgear::strutils::split(rwy_stopway, ".");
        double stopway1 = atof(stop[0].c_str());
        double stopway2 = atof(stop[1].c_str());
        stopway1 *= SG_FEET_TO_METER;
        stopway2 *= SG_FEET_TO_METER;
 
        SGGeod pos_2 = SGGeodesy::direct(pos_1, heading, length);
 
        PositionedID rwy = cache->insertRunway(FGPositioned::RUNWAY, rwy_no, pos_1,
                                               currentAirportPosID, heading, length,
                                               width, displ_thresh1, stopway1,
                                               surface_code);
 
        PositionedID reciprocal = cache->insertRunway(
            FGPositioned::RUNWAY,
            FGRunway::reverseIdent(rwy_no), pos_2,
            currentAirportPosID,
            SGMiscd::normalizePeriodic(0, 360, heading + 180.0),
            length, width, displ_thresh2, stopway2,
            surface_code);
 
        cache->setRunwayReciprocal(rwy, reciprocal);
    }
}
 
void APTLoader::parseRunwayLine850(const string& aptDat, unsigned int lineNum,
                                   const vector<string>& token)
{
    if (token.size() < 26) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid v850 runway line "
                      << "(row code 100): at least 26 fields are required");
        return;
    }
 
    double width = atof(token[1].c_str());
    int surface_code = atoi(token[2].c_str());
    int shoulder_code = atoi(token[3].c_str());
    float smoothness = atof(token[4].c_str());
    int center_lights = atoi(token[5].c_str());
    int edge_lights = atoi(token[6].c_str());
    int distance_remaining = atoi(token[7].c_str());
 
    double lat_1 = atof(token[9].c_str());
    double lon_1 = atof(token[10].c_str());
    SGGeod pos_1(SGGeod::fromDegFt(lon_1, lat_1, 0.0));
    rwy_lat_accum += lat_1;
    rwy_lon_accum += lon_1;
    rwy_count++;
 
    double lat_2 = atof(token[18].c_str());
    double lon_2 = atof(token[19].c_str());
    SGGeod pos_2(SGGeod::fromDegFt(lon_2, lat_2, 0.0));
    rwy_lat_accum += lat_2;
    rwy_lon_accum += lon_2;
    rwy_count++;
 
    double length, heading_1, heading_2;
    SGGeodesy::inverse(pos_1, pos_2, heading_1, heading_2, length);
 
    last_rwy_heading = heading_1;
 
    const string& rwy_no_1(token[8]);
    const string& rwy_no_2(token[17]);
    if (rwy_no_1.empty() || rwy_no_2.empty()) // these tests are weird...
        return;
 
    double displ_thresh1 = atof(token[11].c_str());
    double displ_thresh2 = atof(token[20].c_str());
 
    double stopway1 = atof(token[12].c_str());
    double stopway2 = atof(token[21].c_str());
 
    int markings1 = atoi(token[13].c_str());
    int markings2 = atoi(token[22].c_str());
 
    int approach1 = atoi(token[14].c_str());
    int approach2 = atoi(token[23].c_str());
 
    int tdz1 = atoi(token[15].c_str());
    int tdz2 = atoi(token[24].c_str());
 
    int reil1 = atoi(token[16].c_str());
    int reil2 = atoi(token[25].c_str());
 
    PositionedID rwy = cache->insertRunway(FGPositioned::RUNWAY, rwy_no_1, pos_1,
                                           currentAirportPosID, heading_1, length,
                                           width, displ_thresh1, stopway1, markings1,
                                           approach1, tdz1, reil1,
                                           surface_code, shoulder_code, smoothness,
                                           center_lights, edge_lights, distance_remaining);
 
    PositionedID reciprocal = cache->insertRunway(
        FGPositioned::RUNWAY,
        rwy_no_2, pos_2,
        currentAirportPosID, heading_2, length,
        width, displ_thresh2, stopway2, markings2,
        approach2, tdz2, reil2,
        surface_code, shoulder_code, smoothness,
        center_lights, edge_lights, distance_remaining);
 
    cache->setRunwayReciprocal(rwy, reciprocal);
}
 
void APTLoader::parseWaterRunwayLine850(const string& aptDat,
                                        unsigned int lineNum,
                                        const vector<string>& token)
{
    if (token.size() < 9) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid v850 water runway line "
                      << "(row code 101): at least 9 fields are required");
        return;
    }
 
    double width = atof(token[1].c_str());
 
    double lat_1 = atof(token[4].c_str());
    double lon_1 = atof(token[5].c_str());
    SGGeod pos_1(SGGeod::fromDegFt(lon_1, lat_1, 0.0));
    rwy_lat_accum += lat_1;
    rwy_lon_accum += lon_1;
    rwy_count++;
 
    double lat_2 = atof(token[7].c_str());
    double lon_2 = atof(token[8].c_str());
    SGGeod pos_2(SGGeod::fromDegFt(lon_2, lat_2, 0.0));
    rwy_lat_accum += lat_2;
    rwy_lon_accum += lon_2;
    rwy_count++;
 
    double length, heading_1, heading_2;
    SGGeodesy::inverse(pos_1, pos_2, heading_1, heading_2, length);
 
    last_rwy_heading = heading_1;
 
    const string& rwy_no_1(token[3]);
    const string& rwy_no_2(token[6]);
 
    // For water runways we overload the edge_lights to indicate use of buoys,
    // as they too will be objects.  Also, water runways don't have edge lights.
    PositionedID rwy = cache->insertRunway(FGPositioned::RUNWAY, rwy_no_1, pos_1,
                                           currentAirportPosID, heading_1, length,
                                           width, 0.0, 0.0, 0, 0, 0, 0, 13, 0, 1.0, 0, 1, 0);
 
    PositionedID reciprocal = cache->insertRunway(
        FGPositioned::RUNWAY,
        rwy_no_2, pos_2,
        currentAirportPosID, heading_2, length,
        width, 0.0, 0.0, 13);
 
    cache->setRunwayReciprocal(rwy, reciprocal);
}
 
void APTLoader::parseHelipadLine850(const string& aptDat, unsigned int lineNum,
                                    const vector<string>& token)
{
    if (token.size() < 12) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid v850 helipad line "
                      << "(row code 102): at least 12 fields are required");
        return;
    }
 
    double length = atof(token[5].c_str());
    double width = atof(token[6].c_str());
 
    double lat = atof(token[2].c_str());
    double lon = atof(token[3].c_str());
    SGGeod pos(SGGeod::fromDegFt(lon, lat, 0.0));
    rwy_lat_accum += lat;
    rwy_lon_accum += lon;
    rwy_count++;
 
    double heading = atof(token[4].c_str());
 
    last_rwy_heading = heading;
 
    const string& rwy_no(token[1]);
    int surface_code = atoi(token[7].c_str());
    int markings = atoi(token[8].c_str());
    int shoulder_code = atoi(token[9].c_str());
    float smoothness = atof(token[10].c_str());
    int edge_lights = atoi(token[11].c_str());
 
    cache->insertRunway(FGPositioned::HELIPAD, rwy_no, pos,
                        currentAirportPosID, heading, length,
                        width, 0.0, 0.0, markings, 0, 0, 0,
                        surface_code, shoulder_code, smoothness, 0, edge_lights, 0);
}
 
void APTLoader::parseViewpointLine(const string& aptDat, unsigned int lineNum,
                                   const vector<string>& token)
{
    if (token.size() < 5) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid viewpoint line "
                                           "(row code 14): at least 5 fields are required");
    } else {
        double lat = atof(token[1].c_str());
        double lon = atof(token[2].c_str());
        double elev = atof(token[3].c_str());
        tower = SGGeod::fromDegFt(lon, lat, elev + last_apt_elev);
        cache->insertTower(currentAirportPosID, tower);
    }
}
 
void APTLoader::parsePavementLine850(const vector<string>& token)
{
    if (token.size() >= 5) {
        pavement_ident = token[4];
        if (!pavement_ident.empty() &&
            pavement_ident[pavement_ident.size() - 1] == '\r')
            pavement_ident.erase(pavement_ident.size() - 1);
    } else {
        pavement_ident = "xx";
    }
}
 
void APTLoader::parseNodeLine850(NodeList* nodelist,
                                 const string& aptDat,
                                 unsigned int lineNum, int rowCode,
                                 const vector<string>& token)
{
    static const unsigned int minNbTokens[] = {3, 5, 3, 5, 3, 5};
    assert(111 <= rowCode && rowCode <= 116);
 
    if (token.size() < minNbTokens[rowCode - 111]) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid v850 node line "
                      << "(row code " << rowCode << "): at least " << minNbTokens[rowCode - 111] << " fields are required");
        return;
    }
 
    double lat = atof(token[1].c_str());
    double lon = atof(token[2].c_str());
    SGGeod pos(SGGeod::fromDegFt(lon, lat, 0.0));
 
    FGPavement* pvt = 0;
    if ((!pavement_ident.empty()) || (nodelist->size() == 0)) {
        pvt = new FGPavement(0, pavement_ident, pos);
        nodelist->push_back(pvt);
        pavement_ident = "";
    } else {
        pvt = nodelist->back();
    }
 
    int paintCode = 0;
    int lightCode = 0;
 
    // Line information.  The 2nd last token is the painted line type. Last token
    // is the light type of the segment.  Only applicable to codes 111-114.
    if ((rowCode < 115) && (token.size() == (minNbTokens[rowCode - 111] + 1))) {
        // We've got a line paint code but no lighting code
        paintCode = atoi(token[minNbTokens[rowCode - 111]].c_str());
    }
 
    if ((rowCode < 115) && (token.size() == (minNbTokens[rowCode - 111] + 2))) {
        // We've got a line paint code and a lighting code
        paintCode = atoi(token[minNbTokens[rowCode - 111] - 1].c_str());
        lightCode = atoi(token[minNbTokens[rowCode - 111]].c_str());
    }
 
    if ((rowCode == 112) || (rowCode == 114) || (rowCode == 116)) {
        double lat_b = atof(token[3].c_str());
        double lon_b = atof(token[4].c_str());
        SGGeod pos_b(SGGeod::fromDegFt(lon_b, lat_b, 0.0));
        pvt->addBezierNode(pos, pos_b, (rowCode == 114) || (rowCode == 116), (rowCode == 114), paintCode, lightCode);
    } else {
        pvt->addNode(pos, (rowCode == 113) || (rowCode == 115), (rowCode == 113), paintCode, lightCode);
    }
}
 
void APTLoader::parseCommLine(const string& aptDat,
                              unsigned int lineNum, unsigned int rowCode,
                              const vector<string>& token)
{
    if (token.size() < 3) {
        SG_LOG(SG_GENERAL, SG_WARN,
               aptDat << ":" << lineNum << ": invalid Comm Frequency line "
                      << "(row code " << rowCode << "): at least 3 fields are required");
        return;
    } else if (rwy_count <= 0) {
        SG_LOG(SG_GENERAL, SG_ALERT,
               aptDat << ":" << lineNum << ": no runways, skipping Comm "
                      << "Frequency line for " << last_apt_id);
        // There used to be no 'return' here. Not sure how useful this is, but
        // clearly this code block doesn't make sense without it, so here it is.
        return;
    }
 
    SGGeod pos = SGGeod::fromDegFt(rwy_lon_accum / (double)rwy_count,
                                   rwy_lat_accum / (double)rwy_count,
                                   last_apt_elev);
 
    const bool isAPT1000Code = rowCode > 1000;
    if (isAPT1000Code) {
        rowCode -= 1000;
    }
 
    // short int representing tens of kHz, or just kHz directly
    int freqKhz = std::stoi(token[1]);
    if (isAPT1000Code) {
        const int channel = freqKhz % 25;
        if (channel != 0 && channel != 5 && channel != 10 && channel != 15) {
            SG_LOG(SG_GENERAL, SG_ALERT,
                   aptDat << ":" << lineNum << ": skipping invalid 8.333 kHz Frequency " << freqKhz << " for " << last_apt_id);
            return;
        }
    } else {
        freqKhz *= 10;
        const int remainder = freqKhz % 100;
        // this is to ensure frequencies such as 126.12 become 126.125
        if (remainder == 20 || remainder == 70) {
            freqKhz += 5;
        }
 
        if (freqKhz % 25) {
            SG_LOG(SG_GENERAL, SG_ALERT,
                   aptDat << ":" << lineNum << ": skipping invalid 25 kHz Frequency " << freqKhz << " for " << last_apt_id);
            return;
        }
    }
 
    if (freqKhz < 118000 || freqKhz >= 137000) {
        SG_LOG(SG_GENERAL, SG_ALERT,
               aptDat << ":" << lineNum << ": skipping out of range Frequency " << freqKhz << " for " << last_apt_id);
        return;
    }
 
    int rangeNm = 50;
    FGPositioned::Type ty;
 
    switch (rowCode) {
    case 50:
        ty = FGPositioned::FREQ_AWOS;
        for (size_t i = 2; i < token.size(); ++i) {
            if (token[i] == "ATIS") {
                ty = FGPositioned::FREQ_ATIS;
                break;
            }
        }
        break;
 
    case 51: ty = FGPositioned::FREQ_UNICOM; break;
    case 52: ty = FGPositioned::FREQ_CLEARANCE; break;
    case 53: ty = FGPositioned::FREQ_GROUND; break;
    case 54: ty = FGPositioned::FREQ_TOWER; break;
    case 55:
    case 56: ty = FGPositioned::FREQ_APP_DEP; break;
    default:
        throw sg_range_exception("unsupported apt.dat comm station type");
    }
 
    // Name can contain whitespace. All tokens after the second token are
    // part of the name.
    string name = token[2];
    for (size_t i = 3; i < token.size(); ++i)
        name += ' ' + token[i];
 
    cache->insertCommStation(ty, name, pos, freqKhz, rangeNm,
                             currentAirportPosID);
}
 
// The 'metar.dat' file lists the airports that have METAR available.
bool metarDataLoad(const SGPath& metar_file)
{
    sg_gzifstream metar_in(metar_file);
    if (!metar_in.is_open()) {
        SG_LOG(SG_GENERAL, SG_ALERT, "Cannot open file: " << metar_file);
        return false;
    }
 
    NavDataCache* cache = NavDataCache::instance();
 
    string ident;
    while (metar_in) {
        metar_in >> ident;
        if (ident == "#" || ident == "//") {
            metar_in >> skipeol;
        } else {
            cache->setAirportMetar(ident, true);
        }
    }
 
    return true;
}
 
} // namespace flightgear