Transferencia de arquivos pela internet

var
   TInfo:PTrasnferInfo;
   p,r:Integer;
   Dta,f:string;
   Buffer:array [1..256] of Char;
begin
   Dta:=Socket.ReceiveText;
   if Socket.Data = nil then
   begin
      try
         New(TInfo);
         f:=Chr(13);
         p:=Pos(f,Dta);
         TInfo^.LocalFile:=Copy(Dta,1,p - 1);
         if LstUploads.Items.IndexOf(UpperCase(TInfo^.LocalFile)) >= 0 then
         begin
            Socket.SendText(´O arquivo está sendo usado...´);
            Exit;
         end;
         TInfo^.Action:=TTransferAction(StrToIntDef(Copy(Dta,p + 1,Length(Dta)),0));
         if TInfo^.Action = taDownload then
         begin
            AssignFile(TInfo^.BFile,TInfo^.LocalFile);
            Reset(TInfo^.BFile);
         end
         else if TInfo^.Action = taUpload then
         begin
            AssignFile(TInfo^.TFile,TInfo^.LocalFile);
            ReWrite(TInfo^.TFile);
            LstUploads.Items.Add(UpperCase(TInfo^.LocalFile));
         end;
         Socket.Data:=TInfo;
         if TInfo^.Action = taDownload then
            Socket.SendText(IntToStr(FileSize(TInfo^.BFile)))
         else if TInfo^.Action = taUpload then
            Socket.SendText(´C´);
      except
         Socket.SendText(´Não foi possível acessar o arquivo´);
         Exit;
      end;
   end
   else
   begin
      TInfo:=Socket.Data;
      if TInfo^.Action = taDownload then
      begin
         p:=FilePos(TInfo^.BFile);
         BlockRead(TInfo^.BFile,Buffer,256,r);
         r:=FileSize(TInfo^.BFile);
         Dta:=string(Buffer);
         if (r - p) < 256 then
            Dta:=Copy(Dta,1,r - p);
         Socket.SendText(Dta);
      end
      else if TInfo^.Action = taUpload then
      begin
         Write(TInfo^.TFile,Dta);
         Socket.SendText(´C´);
      end;
   end;
end;