NAME

CheckDigits::M11_003 - compute check digits for PKZ (GDR)

SYNOPSIS

  use Algorithm::CheckDigits;

  $pkz = CheckDigits('pkz');

  if ($pkz->is_valid('150765400354')) {
        # do something
  }

  $cn = $pkz->complete('15076540035');
  # $cn = '150765400354'

  $cd = $pkz->checkdigit('150765400354');
  # $cd = '4'

  $bn = $pkz->basenumber('150765400354');
  # $bn = '150765400354'

DESCRIPTION

ALGORITHM

1.: The checkdigit is set to 0.
2.: From right to left the digits are weighted (multiplied) with 2,4,8,5,10,9,7,3,6,1,2,4.
3.: The products are added.
4.: The sum of step 3 is taken modulo 11.
5.: The value of step 4 is added to a multiple (0..9) of the weight of the checkdigit (2).
6.: The sum of step 5 is taken modulo 11.
7.: The checkdigit is the multiple of the weight of the checkdigit where the value of step 6 equals 10.
8.: If there can't be reached a value of 10 in step 6, the number cannot be taken as a PKZ.

To validate a PKZ apply steps 2 to 4 to the complete number.

METHODS

is_valid($number): Returns true only if $number consists solely of numbers and the last digit is a valid check digit according to the algorithm given above.
Returns false otherwise,
complete($number): The check digit for $number is computed and concatenated to the end of $number.
Returns the complete number with check digit or '' if $number does not consist solely of digits and spaces.
basenumber($number): Returns the basenumber of $number if $number has a valid check digit.
Return '' otherwise.
checkdigit($number): Returns the checkdigit of $number if $number has a valid check digit.
Return '' otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, "<mamawe@cpan.org>"