CheckDigits::M23_002(3) compute check digits for VAT Registration Number (IE)

SYNOPSIS


use Algorithm::CheckDigits;
$dni = CheckDigits('ustid_ie');
if ($dni->is_valid('8473625E')) {
# do something
}
$cn = $dni->complete('8473625');
# $cn = '8473625E'
$cd = $dni->checkdigit('8473625E');
# $cd = 'E'
$bn = $dni->basenumber('8473625E');
# $bn = '8473625'

DESCRIPTION

ALGORITHM

1.
Beginning right all digits are weighted with their position in the number (i.e. the number left from the check digit is multiplied with 2, the next with 3 and so on).
2.
All products are added.
3.
The check digit is the sum from step 2 modulo 23. This number is expressed as the corresponding letter from the alphabet where A-V correspond to 1-22 and W stands for check digit 0.

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, <[email protected]>