program pscan;
{$APPTYPE CONSOLE}

uses
  Winsock,
  Windows;

const
  MaxThreads = 1000;
  
var
  MaxPort, Flag, ScanPort, ThreadCounts: Integer;
  WSAData: TWSAData;
  Server: string;
  TID: Cardinal;

procedure ThreadFunction(AArgs:Pointer);
var
 Sock: TSocket;
 HostAddr: TSockAddrIn;
 
begin
  if ScanPort >= MaxPort then Exit;
  Inc(ScanPort);
  
  HostAddr.sin_port := htons(ScanPort);
  HostAddr.sin_family := AF_INET;
  HostAddr.sin_addr.S_addr := inet_addr(Pchar(Server));
  
  Sock := Socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
  
  if connect(Sock, HostAddr, SizeOf(HostAddr)) <> SOCKET_ERROR then
     Writeln(#10, 'port ', ntohs(HostAddr.sin_port), ' open..');

  closesocket(Sock);
  Dec(ThreadCounts);
end;

begin
  WSAStartup($101, WSAData);

  if ParamCount > 2 then
  begin
    Server := ParamStr(1);
    Val(ParamStr(2), ScanPort, Flag);
	
    if Flag <> 0 then ScanPort := 1;
    Val(ParamStr(3), MaxPort, Flag);
	
    if Flag <> 0 then maxport := 100;
  end else
  begin
    WriteLn('usage: pscan IP minport maxport');
    Exit;
  end;

  ThreadCounts := 0;
  repeat
    if ThreadCounts < MaxThreads then
    begin
      write(#13, 'Pocet vlaken: ', ThreadCounts);
      Inc(ThreadCounts, Ord(CreateThread(nil, 0, @ThreadFunction, nil, 0, TID) <> 0));
      Sleep(20);
    end else 
	  WaitForSingleObject(GetCurrentProcess, 500);
  until ScanPort >= MaxPort;

 WSACleanup;
end.