CheckDigits::M11_008(3) compute check digits for VAT Registration Number (DK)

SYNOPSIS


use Algorithm::CheckDigits;
$ustid = CheckDigits('ustid_dk');
if ($ustid->is_valid('13585628')) {
# do something
}
$cn = $ustid->complete('1358562');
# $cn = '13585628'
$cd = $ustid->checkdigit('13585628');
# $cd = '8'
$bn = $ustid->basenumber('13585628');
# $bn = '1358562';

DESCRIPTION

ALGORITHM

1.
Beginning left every digit is weighted with 2, 7, 6, 5, 4, 3, 2, 1
2.
The weighted digits are added.
3.
The sum from step 2 is taken modulo 11.
4.
The number is valid if the sum from step 3 is zero (0).

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 into the middle of $number.

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

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

Return '' otherwise.

checkdigit($number)
Returns '' if $number is valid.

Return undef otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, <[email protected]>