SYNOPSIS
use Algorithm::CheckDigits;
$ismn = CheckDigits('ismn');
if ($ismn->is_valid('M-345-24680-5')) {
# do something
}
$cn = $ismn->complete('M-345-24680');
# $cn = 'M-345-24680-5'
$cd = $ismn->checkdigit('M-345-24680-5');
# $cd = '5'
$bn = $ismn->basenumber('M-345-24680-5');
# $bn = 'M-345-24680'
DESCRIPTION
ALGORITHM
- 1.
- The 'M' as the first number gets the value 3. Beginning left all numbers are weighted alternatively 3 and 1.
- 2.
- The sum of all products is computed.
- 3.
- The sum of step 3 ist taken modulo 10.
- 4.
- The check digit is the difference between 10 and the number from step 3 taken modulo 10.
METHODS
- is_valid($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.