Something

var
  pdata: array of char;
begin
...
DecodeArray(pchar(pdata)^, boffset);
...
end;


procedure decodearray(pdata: array of Char; boffset: Int64);
var
  ii: Integer;
  test: string;
begin
showmessage(inttostr((ord(pdata[34 + boffset]));
end;