新手问题:如何在DELPHI中把 Mac OS X 的二进制文件读入TMEMO 中以ASCII显示

如题
下面这段程式是把二进制文件以16进制显示在MEMO中.但如何以ASCII来显示呢.
请高手指导一下啊.帮我改改.
我的目的就是把苹果电脑里的二进制文件 打开后转换成文本文件procedure TForm1.Button3Click(Sender: TObject);
var
      iFileHandle,iFileLength,iBytesRead:integer;
      //pszBuffer:PChar;
      //pszBuffer:array   of   char;
      pszBuffer   :   PChar;
      hexBuffer:string;
      hexChar:string[4];
      i:integer;
  begin
      if   openDialog1.Execute   then
      begin
          memo1.Clear;
          iFileHandle:=fileOpen(opendialog1.FileName,fmOpenRead);   
          iFileLength:=FileSeek(iFileHandle,0,2);
          FileSeek(iFileHandle,0,0);
          //setLength(pszBuffer,iFileLength+1);
          pszBuffer   :=   PChar(AllocMem(iFileLength   +   1));          iBytesRead:=FileRead(iFileHandle,pszbuffer^,iFileLength);
          fileClose(iFileHandle);
          for   i:=0   to   iBytesRead   do
          begin
              hexChar:=format('%2x',[byte(pszBuffer[i])]);
              hexBuffer:=hexBuffer+upperCase(hexChar);
          end;
          memo1.Lines.Add(hexBuffer);      end;
  end;