<?php
class Telnet // nach RFC854
{
    var $Server_Socket = NULL;
    var $Server_Error_Number;
    var $Server_Error_String;

    function Telnet($Host, $Port, $TimeOut)
    {
        $this->Server_Socket=@fsockopen($Host, $Port, $Error_Number, $Error_String);
        if (!$this->Server_Socket)
        {
            $this->Server_Error_Number=$Error_Number;
            $this->Server_Error_String=$Error_String;
        }
        else socket_set_timeout($this->Server_Socket, $TimeOut);
    }

    function Beenden()
    {
        if ($this->Server_Socket)
        {
            If (fclose($this->Server_Socket))
            {
                $this->Server_Socket=NULL;
                return 1;
            }
            else return 0;
        }
        else return 0;
    }


    function Schreiben($Command)
    {
        if ($this->Server_Socket)
        {
            $Replace=chr(255);
            $Command=str_replace($Replace, $Replace.$Replace, $Command);
            if (@fwrite($this->Server_Socket, $Command)) return 1;
            else return 0;
        }
        else return 0;
    }
    
    function Lesen($Bis)
    {
        if ($this->Server_Socket)
        {
            UnSet($String);
            $Array['IAC']=chr(255);
            $Array['DONT']=chr(254);
            $Array['DO']=chr(253);
            $Array['WONT']=chr(252);
            $Array['WILL']=chr(251);
            $Array['NULL']=chr(0);
            while (true)
            {
                $Charakter=fgetc($this->Server_Socket);

                if ($Charakter===false) return $String;

                if ($Charakter=="\021") continue;
                if ($Charakter==$Array['NULL']) continue;
                if ($Charakter!=$Array['IAC'])
                {
                    $String.=$Charakter;
                    if ($Bis==(substr($String,strlen($String)-strlen($Bis)))) return $String;
                    else continue;
                }
                $Charakter=fgetc($this->Server_Socket);

                if ($Charakter==$Array['IAC']) $String.=$Charakter;
                else
                {
                    $Array['Opt']=fgetc($this->Server_Socket);
                    if (($Charakter==$Array['DONT']) ||($Charakter==$Array['DO'])) fwrite($this->Server_Socket, $Array['IAC'].$Array['WONT'].$Array['Opt']);
                    elseif (($Charakter==$Array['WONT']) || ($Charakter==$Array['WILL'])) fwrite($this->Server_Socket, $Array['IAC'].$Array['DONT'].$Array['Opt']);
                }
            }
        }
        else return 0;
    }
}