public float haversine(Server serv){
//http://www.stormconsultancy.co.uk/blog/development/code-snippets/the-haversine-formula-in-c-and-sql/
//modified by me a little
//@returns angular distance
Contract.Requires(serv != null);
Contract.Requires(!(float.IsNaN(serv.lat)|| float.IsNegativeInfinity(serv.lat)|| float.IsPositiveInfinity(serv.lat)));
Contract.Requires(!(float.IsNaN(serv.lon) || float.IsNegativeInfinity(serv.lon) || float.IsPositiveInfinity(serv.lon)));
double dLat = (serv.lat-lat)/180*Math.PI;
double dLon = (serv.lon-lon)/180*Math.PI;
double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
Math.Cos(lat/180*Math.PI) *Math.Cos(serv.lon/180*Math.PI) *
Math.Sin(dLon / 2) * Math.Sin(dLon / 2);
return (float)(2 * Math.Asin(Math.Min(1, Math.Sqrt(a))));
}
public async Task<float> measureUploadSpeed(Server server, int size = 1024*482){
Contract.Requires(server != null);
Contract.Requires(size >= 0);
var prefix = new[]{
(byte) '&',
(byte) 'c',
(byte) 'o',
(byte) 'n',
(byte) 't',
(byte) 'e',
(byte) 'n',
(byte) 't',
(byte) '0',
(byte) '=',
};
stage = Stage.UPLOAD;
var req = HttpWebRequest.Create(new Uri(server.uri, "upload.php")) as HttpWebRequest;
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore);
req.ContentLength = countOfPieces*(defaultSize + prefix.Length);
req.KeepAlive = true;
req.Credentials = CredentialCache.DefaultCredentials;
req.Proxy = hch.Proxy;
emitProgressEvent(0);
using (var str = req.GetRequestStream()) {
using (var ums = new RangedRandomBytesStream(defaultSize, (byte)'A', (byte)'z'))
{
int j = 0;
EventedStream.dataLoadListener evtListener = (o, bytes) => emitProgressEvent(100 * (j + bytes / defaultSize) / countOfPieces);
ums.onLoading += evtListener;
sw.Restart();
for (; j < countOfPieces; j++)
{
prefix[8] = (byte)('0' + j);
await str.WriteAsync(prefix, 0, prefix.Length);
await str.FlushAsync();
await ums.CopyToAsync(str);
ums.Position = 0;
await str.FlushAsync();
}
sw.Stop();
ums.onLoading -= evtListener;
}
}
await req.GetResponseAsync().ContinueWith(t => t.Result.GetResponseStream().Close());
float speed = (float) (req.ContentLength/(sw.Elapsed.TotalSeconds));
emitProgressEvent(100);
emitMeasuredEvent(speed);
return speed;
}
protected async Task<Server> convertServersXMLToFilteredServersList(XmlNodeList servers){
Contract.Requires(servers != null);
if (servers.Count == 0) return null;
closestKnownServer = new Server(servers[0]);
closestKnownServer.dist=haversine(closestKnownServer);
this.servers.Add(closestKnownServer);
var pingTasks = new List<Task>();
for (int i = 1; i < servers.Count;i++){
Server server;
try {
server = new Server(servers[i]);
} catch {
continue;
}
server.dist = haversine(server);
if (closestKnownServer.dist - server.dist > distTreshold) {
closestKnownServer = server;
this.servers.Add(server);
this.servers.RemoveAt(0);
}
else if (Math.Abs(closestKnownServer.dist - server.dist) <= distTreshold) {
this.servers.Add(server);
//BUG: we need to enable it but it causes hang
pingTasks.Add(
Task.Run(async () =>{
await server.ping();
if (closestKnownServer.latency > server.latency) {
closestKnownServer = server;
this.servers.RemoveAt(0);
}
})
);
}
}
await Task.WhenAll(pingTasks);//bug : it writes it has finished before it is really finished
return closestKnownServer;
}
public async Task<float> measureDownloadSpeed(Server server,int size=100){
Contract.Requires(server != null);
Contract.Requires(size >= 0);
stage = Stage.DOWNLOAD;
var uri = new Uri(server.uri, "random" + "4000x4000" + ".jpg");
var speed=await measureDownloadSpeed(uri);
emitProgressEvent(100);//uri = null . WHY?????
emitMeasuredEvent(speed);
return speed;
}
protected void convertServersXMLToServersList(XmlNodeList servers){
Contract.Requires(servers != null);
for (int i = 1; i < servers.Count;i++){
var server = new Server(servers[i]);
this.servers.Add(server);
}
}
