Strings Delphi

Title: How to Convert a String to an Unique number
type
UInt64 = 0..9223372036854775807;
function Unc(s: string): UInt64;
var
x: Integer;
begin
Result := 0;
for x := 1 to Length(s) do Result := Result + ((Ord(s[x])) shl ((x - 1) * 8));
end;