NAME

CheckDigits::M11_015 - compute check digits for ESR5 (CH)

SYNOPSIS

  use Algorithm::CheckDigits;

  $ustid = CheckDigits('esr5_ch');

  if ($ustid->is_valid('050001000012000 241170032660178 10304')) {
        # do something
  }

  $cn = $ustid->complete('0001000012000 241170032660178 10304');
  # $cn = '050001000012000 241170032660178 10304'

  $cd = $ustid->checkdigit('0001000012000 241170032660178 10304');
  # $cd = '05'

  $bn = $ustid->basenumber('050001000012000 241170032660178 10304');
  # $bn = '0001000012000 241170032660178 10304';

DESCRIPTION

ALGORITHM

1. Beginning right all digits are weighted with the repeating sequence 2, 3, 4, 5, 6, 7.
2. The weighted digits are added.
3. The sum from step 2 is taken modulo 11.
4. The checkdigit is 11 minus the sum from step 3. If the difference is 11, the checkdigit is 00.

METHODS

is_valid($number)

Returns true only if $number consists solely of numbers and hyphens and the two digits in the middle are valid check digits according to the algorithm given above.

Returns false otherwise,

complete($number)

The check digit for $number is computed and inserted before the $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits, spaces.

basenumber($number)

Returns the basenumber of $number if $number has a valid check digit.

Return '' otherwise.

checkdigit($number)

Returns the check digits of $number if $number has valid check digits.

Return '' otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, <mathias@weidner.in-bad-schmiedeberg.de>

SEE ALSO

perl, CheckDigits, http://www.pruefziffernberechnung.de/E/Einzahlungsschein-CH.shtml (german), http://www.sic.ch/de/dl_tkicch_dta.pdf, page 52 (german)