ReNamer:Scripts:EAN-13

This script will calculate the checksum digit for the EAN-13 barcode. The checksum digit will be appended to the end of the base name.

Although EAN-13 codes are 13 digits long (12 + check digit) the script will work for codes of any length.

Input	Output
002010000000.png	0020100000007.png
002010000001.png	0020100000014.png
002010000002.png	0020100000021.png
002010000003.png	0020100000038.png
007567816412.png	0075678164125.png

Tested

• ReNamer 5.50+ Beta

Code

Author: Denis Kozlov. Date: 9 June 2010.

function EAN13Checksum(const EAN13: String): Integer;
var
  I, Digit: Integer;
  Odd: Boolean;
  Sum: Integer;
begin
  Sum := 0;
  Odd := True;
  for I := Length(EAN13) downto 1 do
  begin
    Digit := StrToIntDef(EAN13[I], 0);
    if Odd then
      Sum := Sum + Digit * 3
    else
      Sum := Sum + Digit;
   Odd := not Odd;
  end;
  Result := Sum mod 10;
  if Result <> 0 then
    Result := 10 - Result;
end;

var
  BaseName, Ext: WideString;
  Checksum: Integer;

begin
  BaseName := WideExtractBaseName(FileName);
  Ext := WideExtractFileExt(FileName);
  Checksum := EAN13Checksum(BaseName);
  FileName := BaseName + IntToStr(Checksum) + Ext;
end.