if pop3FctRSet in FFctSet then begin
        FFctPrv := pop3FctRSet;
        FFctSet := FFctSet - [FFctPrv];
        RSet;
        Exit;
    end;

    if pop3FctAPop in FFctSet then begin
        FFctPrv := pop3FctAPop;
        FFctSet := FFctSet - [FFctPrv];
        APop;
        Exit;
    end;

    if pop3FctRetr in FFctSet then begin
        FFctPrv := pop3FctRetr;
        FFctSet := FFctSet - [FFctPrv];
        Retr;
        Exit;
    end;

    if pop3FctTop in FFctSet then begin
        FFctPrv := pop3FctTop;
        FFctSet := FFctSet - [FFctPrv];
        Top;
        Exit;
    end;

    if pop3FctStat in FFctSet then begin
        FFctPrv := pop3FctStat;
        FFctSet := FFctSet - [FFctPrv];
        Stat;
        Exit;
    end;

    if pop3FctUidl in FFctSet then begin
        FFctPrv := pop3FctUidl;
        FFctSet := FFctSet - [FFctPrv];
        Uidl;
        Exit;
    end;

    if pop3FctLast in FFctSet then begin
        FFctPrv := pop3FctLast;
        FFctSet := FFctSet - [FFctPrv];
        Last;
        Exit;
    end;

    if pop3FctQuit in FFctSet then begin
        FFctPrv := pop3FctQuit;
        FFctSet := FFctSet - [FFctPrv];
        Quit;
        Exit;
    end;

    {$IFDEF TRACE} TriggerDisplay('! HighLevelAsync done'); {$ENDIF}
    FFctSet          := [];
    FNextRequest     := nil;
    FRequestDoneFlag := FALSE;
    TriggerRequestDone(FHighLevelResult);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.HighLevelAsync(
    RqType : Tpop3Request; Fcts : Tpop3FctSet);
begin
    if FConnected and (pop3FctConnect in Fcts) then
        raise pop3Exception.Create('pop3 component already connected');
    CheckReady;
    FLastResponseSave := FLastResponse;
    FStatusCodeSave   := -1;
    FRequestType      := RqType;
    FRequestResult    := 0;
    FFctSet           := Fcts;
    FFctPrv           := pop3FctNone;
    FHighLevelResult  := 0;
    FHighLevelFlag    := TRUE;
    FLastResponse     := '';
    FErrorMessage     := '';
    FRestartFlag      := FALSE;
    DoHighLevelAsync;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.ProcessUidl(Sender : TObject);
begin
    ExtractUidl(FMsgNum, FMsgUidl);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.ProcessList(Sender : TObject);
begin
    ExtractNumbers(FMsgNum, FMsgSize);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function TCustomPop3Cli.ExtractUidl(var N1 : Integer; var N2 : String) : Boolean;
var
    p : PChar;
begin
    Result := FALSE;
    N1     := 0;
    N2     := '';

{$IFDEF VER80}
    { Delphi 1 do not automatically nul terminate strings }
    FLastResponse := FLastResponse + #0;
{$ENDIF}

    { Search for first digit in response }
    p := @FLastResponse[1];
    while (p^ <> #0) and (not (p^ in ['0'..'9'])) do
        Inc(p);
    if p^ = #0 then { Invalid response, need a number }
        Exit;

    { Convert first number }
    N1 := atoi(p);

    { Search end of number }
    while (p^ <> #0) and (p^ in ['0'..'9']) do
        Inc(p);

    { Search Uidl }
    while (p^ = ' ') do
        Inc(p);

    { Copy UIDL }
    while (p^ <> #0) and (p^ in [#33..#126]) do begin
        N2 := N2 + p^;
        Inc(p);
    end;

    Result := TRUE;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function TCustomPop3Cli.ExtractNumbers(var N1 : Integer; var N2 : Integer) : Boolean;
var
    p : PChar;
begin
    Result := FALSE;

{$IFDEF VER80}
    { Delphi 1 do not automatically nul terminate strings }
    FLastResponse := FLastResponse + #0;
{$ENDIF}

    { Search for first digit in response }
    p := @FLastResponse[1];
    while (p^ <> #0) and (not (p^ in ['0'..'9'])) do
        Inc(p);
    if p^ = #0 then begin
        { Invalid response, need a number }
        N1 := 0;
        N2 := 0;
        Exit;
    end;

    { Convert first number }
    N1 := atoi(p);

    { Search end of number }
    while (p^ <> #0) and (p^ in ['0'..'9']) do
        Inc(p);

    { Search next number }
    p := stpblk(p);

    if p^ = #0 then begin
        { Invalid response, need a number }
        N1 := 0;
        N2 := 0;
        Exit;
    end;

    N2     := atoi(p);
    Result := TRUE;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.SendCommand(Cmd : String);
begin
    Display('> ' + Cmd);
    Application.ProcessMessages;
    FWSocket.SendStr(Cmd + #13 + #10);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function TCustomPop3Cli.OkResponse : Boolean;
begin
    Result := ((Length(FLastResponse) > 0) and (FLastResponse[1] = '+'));
    if Result then
        FStatusCode := 0
    else
        FStatusCode := 500;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Display(Msg : String);
begin
    if Assigned(FOnDisplay) then
        FOnDisplay(Self, Msg);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.ClearErrorMessage;
begin
    FErrorMessage := '';
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.SetErrorMessage;
begin
    if FErrorMessage = '' then
        FErrorMessage := FLastResponse;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.CheckReady;
begin
    if not (FState in [pop3Ready, pop3InternalReady]) then
        raise pop3Exception.Create('POP3 component not ready');
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.StateChange(NewState : TPop3State);
begin
    if FState <> NewState then begin
        FState := NewState;
        TriggerStateChange;
    end;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.DisplayLastResponse;
begin
     TriggerDisplay('< ' + FLastResponse);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.ExecAsync(
    RqType      : TPop3Request;
    Cmd         : String;             { Command to execute                     }
    NextState   : TPop3ProtocolState; { Next protocol state in case of success }
    DoneAsync   : TPop3NextProc);     { What to do when done                   }
begin
    CheckReady;

    if not FConnected then
        raise Pop3Exception.Create('POP3 component not connected');

    if not FHighLevelFlag then
        FRequestType := RqType;

    FRequestDoneFlag   := FALSE;
    FNext              := NextExecAsync;
    FNextProtocolState := NextState;
    FDoneAsync         := DoneAsync;
    StateChange(pop3WaitingResponse);
    SendCommand(Cmd);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.NextExecAsync;
begin
    DisplayLastResponse;

    if not OkResponse then begin
        FRequestResult := FStatusCode;
        SetErrorMessage;
        TriggerRequestDone(FRequestResult);
        Exit;
    end;

    FRequestResult := 0;
    FProtocolState := FNextProtocolState;

    if Assigned(FDoneAsync) then
        FDoneAsync
    else
        TriggerRequestDone(FRequestResult);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.User;
begin
    if FProtocolState > pop3WaitingUser then begin
        FErrorMessage := '-ERR USER command invalid now';
        Display(FErrorMessage);
        raise Pop3Exception.Create(FErrorMessage);
    end;

    FFctPrv := pop3FctUser;
    ExecAsync(pop3User, 'USER ' + Trim(FUserName), pop3WaitingPass, nil);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Connect;
begin
    CheckReady;
    if FConnected then
        raise Pop3Exception.Create('POP3 component already connected');

    if not FHighLevelFlag then
        FRequestType  := pop3Connect;

    FRequestDoneFlag  := FALSE;
    FReceiveLen       := 0;
    FRequestResult    := 0;
    StateChange(pop3DnsLookup);
    FWSocket.OnDataSent      := nil;
    FWSocket.OnDnsLookupDone := WSocketDnsLookupDone;
    FWSocket.DnsLookup(FHost);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Abort;
begin
    StateChange(pop3Abort);
    FWSocket.CancelDnsLookup;
    FWSocket.Abort;
    StateChange(pop3Ready);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Pass;
begin
    if FProtocolState > pop3WaitingPass then begin
        FErrorMessage := '-ERR PASS command invalid now';
        Display(FErrorMessage);
        raise Pop3Exception.Create(FErrorMessage);
    end;

    FFctPrv := pop3FctPass;
    ExecAsync(pop3Pass, 'PASS ' + Trim(FPassWord), pop3Transaction, nil);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.RPop;
begin
    if FProtocolState > pop3WaitingPass then begin
        FErrorMessage := '-ERR RPOP command invalid now';
        Display(FErrorMessage);
        raise Pop3Exception.Create(FErrorMessage);
    end;

    FFctPrv := pop3FctRPop;
    ExecAsync(pop3RPop, 'RPOP ' + Trim(FPassWord), pop3Transaction, nil);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.APop;
begin
    if FProtocolState <> pop3WaitingUser then begin
        FErrorMessage := '-ERR APOP command invalid now';
        Display(FErrorMessage);
        raise Pop3Exception.Create(FErrorMessage);
    end;

    if FTimeStamp = '' then begin
        FErrorMessage := '-ERR Server do not support APOP (no timestamp)';
        Display(FErrorMessage);
        raise Pop3Exception.Create(FErrorMessage);
    end;

    FFctPrv := pop3FctAPop;
    ExecAsync(pop3APop, 'APOP ' + Trim(FUserName) + ' ' +
                        StrMD5(FTimeStamp + FPassWord),
                        pop3Transaction, nil);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Quit;
begin
    CheckReady;
    FFctPrv := pop3FctQuit;
    if not FConnected then begin
        { We are not connected, it's ok... }
        FRequestType     := pop3Quit;
        FRequestDoneFlag := FALSE;
        TriggerRequestDone(0);
        Exit;
    end;
    ExecAsync(pop3Quit, 'QUIT', pop3Disconnected, nil); { Should I force a FWSocket.Close }
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure TCustomPop3Cli.Stat;
begin
    FFctPrv := pop3FctStat;