MissionPlanner.srtm.get3secfile C# (CSharp) Method

        static void get3secfile(object name)
        {
            string baseurl1sec = "http://firmware.ardupilot.org/SRTM/USGS/SRTM1/version2_1/SRTM1/";
            string baseurl = "http://firmware.ardupilot.org/SRTM/";

            // check file doesnt already exist
            if (File.Exists(datadirectory + Path.DirectorySeparatorChar + (string) name))
            {
                FileInfo fi = new FileInfo(datadirectory + Path.DirectorySeparatorChar + (string) name);
                if (fi.Length != 0)
                    return;
            }

            int checkednames = 0;
            List<string> list = new List<string>();

            // load 1 arc seconds first
            //list.AddRange(getListing(baseurl1sec));
            // load 3 arc second
            list.AddRange(getListing(baseurl));

            foreach (string item in list)
            {
                List<string> hgtfiles = new List<string>();

                hgtfiles = getListing(item);

                foreach (string hgt in hgtfiles)
                {
                    checkednames++;
                    if (hgt.Contains((string) name))
                    {
                        // get file

                        gethgt(hgt, (string) name);
                        return;
                    }
                }
            }

            // if there are no http exceptions, and the list is >= 20, then everything above is valid
            // 15760 is all srtm3 and srtm1
            if (list.Count >= 12 && checkednames > 14000 && !oceantile.Contains((string) name))
            {
                // we must be an ocean tile - no matchs
                oceantile.Add((string) name);
            }
        }