TSessionAvailable  = procedure (Sender: TObject; ErrCode: Word) of object;
  TSessionConnected  = procedure (Sender: TObject; ErrCode: Word) of object;
  TDnsLookupDone     = procedure (Sender: TObject; ErrCode: Word) of object;
  TChangeState       = procedure (Sender: TObject;
                                 OldState, NewState : TSocketState) of object;
  TDebugDisplay      = procedure (Sender: TObject; var Msg : String) of object;
  TWSocketSyncNextProc = procedure of object;
  TWSocketOption       = (wsoNoReceiveLoop, wsoTcpNoDelay, wsoSIO_RCVALL);
  TWSocketOptions      = set of TWSocketOption;
{$IFDEF DELPHI4_UP}
  { TSocket type definition has been removed starting from Delphi 4 }
  TSocket = u_int;
{$ENDIF}

  TCustomWSocket = class(TComponent)
  private
    FDnsResult          : String;
    FDnsResultList      : TStrings;
    FSendFlags          : Integer;
    FLastError          : Integer;
    FWindowHandle       : HWND;
    FDnsLookupBuffer    : array [0..MAXGETHOSTSTRUCT] of char;
    FDnsLookupCheckMsg  : Boolean;
    FDnsLookupTempMsg   : TMessage;
  {$IFDEF DELPHI1}
    FTrumpetCompability : Boolean;
  {$ENDIF}
  protected
    FHSocket            : TSocket;
    FASocket            : TSocket;               { Accepted socket }
    FAddrStr            : String;
    FAddrResolved       : Boolean;
    FAddrFormat         : Integer;
    FAddrAssigned       : Boolean;
    FProto              : integer;
    FProtoAssigned      : Boolean;
    FProtoResolved      : Boolean;
    FLocalPortResolved  : Boolean;
    FProtoStr           : String;
    FPortStr            : String;
    FPortAssigned       : Boolean;
    FPortResolved       : Boolean;
    FPortNum            : Integer;
    FLocalPortStr       : String;
    FLocalPortNum       : Integer;
    FLocalAddr          : String;     { IP address for local interface to use }
    FType               : Integer;
    FBufList            : TList;
    FBufSize            : Integer;    { TWSocket internal buffer chunk size   }
    FLingerOnOff        : TSocketLingerOnOff;
    FLingerTimeout      : Integer;              { In seconds, 0 = disabled }
    FListenBacklog      : Integer;
    ReadLineCount       : Integer;
    bAllSent            : Boolean;
    FReadCount          : LongInt;
    FPaused             : Boolean;
    FCloseInvoked       : Boolean;
    FFlushTimeout       : Integer;
    FMultiThreaded      : Boolean;
    FDnsLookupHandle    : THandle;
    { More info about multicast can be found at:                              }
    {    http://ntrg.cs.tcd.ie/undergrad/4ba2/multicast/antony/               }
    {    http://www.tldp.org/HOWTO/Multicast-HOWTO-6.html                     }
    FMultiCast          : Boolean;
    { Multicast addresses consists of a range of addresses from 224.0.0.0 to  }
    { 239.255.255.255. However, the multicast addresses from 224.0.0.0 to     }
    { 224.0.0.255 are reserved for multicast routing information; Application }
    { programs should use multicast addresses outside this range.             }
    FMultiCastAddrStr   : String;
    FMultiCastIpTTL     : Integer;
    FReuseAddr          : Boolean;
    FComponentOptions   : TWSocketOptions;
    FState              : TSocketState;
    FRcvdFlag           : Boolean;
    FTerminated         : Boolean;
    FSelectEvent        : LongInt;
    FSelectMessage      : WORD;
    FOnSessionAvailable : TSessionAvailable;
    FOnSessionConnected : TSessionConnected;
    FOnSessionClosed    : TSessionClosed;
    FOnChangeState      : TChangeState;
    FOnDataAvailable    : TDataAvailable;
    FOnDataSent         : TDataSent;
    FOnSendData         : TSendData;
    { FOnLineTooLong      : TNotifyEvent; }
    FOnDnsLookupDone    : TDnsLookupDone;
    FOnError            : TNotifyEvent;
    FOnBgException      : TBgExceptionEvent;
    FOnDisplay          : TDebugDisplay;
    FOnMessagePump      : TNotifyEvent;
    FThreadId           : THandle;
    FSocketSndBufSize   : Integer;  { Winsock internal socket send buffer size }
    procedure   WndProc(var MsgRec: TMessage); virtual;
    procedure   AllocateSocketHWnd; virtual;
    procedure   DeallocateSocketHWnd; virtual;
    procedure   SocketError(sockfunc: string);
    procedure   WMASyncSelect(var Msg: TMessage); message WM_ASYNCSELECT;
    procedure   WMAsyncGetHostByName(var Msg: TMessage); message WM_ASYNCGETHOSTBYNAME;
    procedure   WMAsyncGetHostByAddr(var Msg: TMessage); message WM_ASYNCGETHOSTBYADDR;
    procedure   WMCloseDelayed(var Msg: TMessage); message WM_CLOSE_DELAYED;
    procedure   WMRelease(var Msg: TMessage); message WM_WSOCKET_RELEASE;
    procedure   ChangeState(NewState : TSocketState);
    procedure   TryToSend; virtual;
    procedure   ASyncReceive(Error : Word; MySocketOptions : TWSocketOptions);
    procedure   AssignDefaultValue; virtual;
    procedure   InternalClose(bShut : Boolean; Error : Word); virtual;
    procedure   InternalAbort(ErrCode : Word); virtual;
    procedure   Notification(AComponent: TComponent; operation: TOperation); override;
    procedure   SetSendFlags(newValue : TSocketSendFlags);
    function    GetSendFlags : TSocketSendFlags;
    procedure   SetAddr(InAddr : String);
    function    GetAddr : String;
    procedure   SetRemotePort(sPort : String); virtual;
    function    GetRemotePort : String;
    procedure   SetLocalAddr(sLocalAddr : String);
    procedure   SetLocalPort(sLocalPort : String);
    procedure   SetProto(sProto : String); virtual;
    function    GetProto : String;
    function    GetRcvdCount : LongInt; virtual;
    procedure   BindSocket; virtual;
    procedure   SendText(Str : String);
    function    RealSend(Data : Pointer; Len : Integer) : Integer; virtual;
    procedure   RaiseExceptionFmt(const Fmt : String; args : array of const); virtual;
    procedure   RaiseException(const Msg : String); virtual;
    procedure   HandleBackGroundException(E: Exception); virtual;
    function    GetReqVerLow: BYTE;
    procedure   SetReqVerLow(const Value: BYTE);
    function    GetReqVerHigh: BYTE;
    procedure   SetReqVerHigh(const Value: BYTE);
    procedure   TriggerDisplay(Msg : String);
    procedure   TriggerSendData(BytesSent : Integer);
    function    TriggerDataAvailable(Error : Word) : Boolean; virtual;
    procedure   TriggerSessionAvailable(Error : Word); virtual;
    procedure   TriggerSessionConnectedSpecial(Error : Word); virtual;
    procedure   TriggerSessionConnected(Error : Word); virtual;
    procedure   TriggerSessionClosed(Error : Word); virtual;
    procedure   TriggerDataSent(Error : Word); virtual;
    procedure   TriggerChangeState(OldState, NewState : TSocketState); virtual;
    procedure   TriggerDNSLookupDone(Error : Word); virtual;
    procedure   TriggerError; virtual;
    function    DoRecv(var Buffer;
                       BufferSize : Integer;
                       Flags      : Integer) : Integer; virtual;
    function    DoRecvFrom(FHSocket    : TSocket;
                           var Buffer;
                           BufferSize  : Integer;
                           Flags       : Integer;
                           var From    : TSockAddr;
                           var FromLen : Integer) : Integer; virtual;
    procedure Do_FD_CONNECT(var Msg: TMessage); virtual;
    procedure Do_FD_READ(var Msg: TMessage); virtual;
    procedure Do_FD_WRITE(var Msg: TMessage); virtual;
    procedure Do_FD_ACCEPT(var Msg: TMessage); virtual;
    procedure Do_FD_CLOSE(var Msg: TMessage); virtual;
    procedure DupConnected; virtual;
  public
    sin         : TSockAddrIn;
    constructor Create(AOwner: TComponent); override;
    destructor  Destroy; override;
    procedure   Connect; virtual;
    procedure   Close; virtual;
    procedure   CloseDelayed; virtual;
    procedure   Release; virtual;
    procedure   Abort; virtual;
    procedure   Flush; virtual;
    procedure   WaitForClose; virtual;
    procedure   Listen; virtual;
    function    Accept: TSocket; virtual;
    function    Receive(Buffer : Pointer; BufferSize: integer) : integer; virtual;
    function    ReceiveStr : string; virtual;
    function    ReceiveFrom(Buffer      : Pointer;
                            BufferSize  : Integer;
                            var From    : TSockAddr;
                            var FromLen : Integer) : integer; virtual;
    function    PeekData(Buffer : Pointer; BufferSize: integer) : integer;
    function    Send(Data : Pointer; Len : Integer) : integer; virtual;
    function    SendTo(Dest    : TSockAddr;
                       DestLen : Integer;
                       Data    : Pointer;
                       Len     : Integer) : integer; virtual;
    function    SendStr(const Str : String) : Integer; virtual;
    procedure   DnsLookup(const AHostName : String); virtual;
    procedure   ReverseDnsLookup(const HostAddr: String); virtual;
    procedure   CancelDnsLookup; virtual;
    function    GetPeerAddr: string; virtual;
    function    GetPeerPort: string; virtual;
    function    GetPeerName(var Name : TSockAddrIn; NameLen : Integer) : integer; virtual;
    function    GetXPort: string; virtual;
    function    GetXAddr: string; virtual;
    function    TimerIsSet(var tvp : TTimeVal) : Boolean; virtual;
    procedure   TimerClear(var tvp : TTimeVal); virtual;
    function    TimerCmp(var tvp : TTimeVal; var uvp : TTimeVal; IsEqual : Boolean) : Boolean; virtual;
    function    GetSockName(var saddr : TSockAddrIn; var saddrlen : Integer) : integer; virtual;
    procedure   SetLingerOption;
    procedure   Dup(NewHSocket : TSocket); virtual;
    procedure   Shutdown(How : Integer); virtual;
    procedure   Pause; virtual;
    procedure   Resume; virtual;
    procedure   PutDataInSendBuffer(Data : Pointer; Len : Integer); virtual;
    procedure   PutStringInSendBuffer(const Str : String);
    procedure   DeleteBufferedData;
    procedure   MessagePump; virtual;
{$IFDEF COMPILER2_UP}
    procedure   ThreadAttach;
    procedure   ThreadDetach;
    procedure   MessageLoop;
    function    ProcessMessage : Boolean;
    procedure   ProcessMessages;
{$ENDIF}
{$IFDEF NOFORMS}
    property    Terminated         : Boolean        read  FTerminated
                                                    write FTerminated;
    property    OnMessagePump      : TNotifyEvent   read  FOnMessagePump
                                                    write FOnMessagePump;
{$ENDIF}
  protected
    property PortNum : Integer                      read  FPortNum;
    property Handle : HWND                          read  FWindowHandle;
    property HSocket : TSocket                      read  FHSocket
                                                    write Dup;

    property Addr : string                          read  GetAddr
                                                    write SetAddr;
    property Port : string                          read  GetRemotePort
                                                    write SetRemotePort;