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Algorithm::CheckDigits::M23_002.3pm

NAME

CheckDigits::M23_002 - 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, <mathias@weidner.in-bad-schmiedeberg.de>

SEE ALSO

perl, CheckDigits, www.pruefziffernberechnung.de.