NAME

CheckDigits::MXX_001 - compute check digits for Personalausweis (DE)

SYNOPSIS

  use Algorithm::CheckDigits;

  $pa = CheckDigits('pa_de');

  if ($pa->is_valid('2406055684D<<6810203<0705109<6')) {
	# do something
  }

  if ($pa->is_valid('2406055684') {
  	# do_something
  }

  $cn = $pa->complete('240605568_D<<681020_<070510_<_');
  # $cn = '2406055684D<<6810203<0705109<6'

  $cd = $pa->checkdigit('2406055684D<<6810203<0705109<6');
  # $cd = '6'

  $bn = $pa->basenumber('2406055684D<<6810203<0705109<6');
  # $bn = '240605568_D<<681020_<070510_<_'
  

DESCRIPTION

ALGORITHM

1. Beginning left all digits are weighted with 7,3,1,7,3,1,...

2. The sum of those products is computed.

3. The checksum is the last digit of the sum from step 2 (modulo 10).

4. Step 1 to 3 is performed for every part of the number and for all 3 parts including the particular checkdigit to compute the total checksum.

   If the number solely consists of digits, the checksum is just computed once according to algorithm above given.

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>

THANKS

Aaron W. West pointed me to a fault in the computing of the check digit.

SEE ALSO

perl, CheckDigits, www.pruefziffernberechnung.de, www.export911.com/e911/coding/upcChar.htm, www.adams1.com/pub/russadam/upccode.html, http://www.upcdatabase.com.