SYNOPSIS
use Algorithm::CheckDigits;
$dem = CheckDigits('dem');
if ($dem->is_valid('GD0645027K1')) {
# do something
}
$cn = $dem->complete('GD0645027K');
# $cn = 'GD0645027K1'
$cd = $dem->checkdigit('GD0645027K1');
# $cd = '1'
$bn = $dem->basenumber('GD0645027K1');
# $bn = 'GD0645027K'
DESCRIPTION
ALGORITHM
The algorithm is a variation of the Verhoeff scheme.- 0
- All letters are changed to numbers.
- 1
- All digits are permutated according to a permutation table.
- 2
- The permutated digits are combined using a die.der table. The first with the second, the result with the third, this result with the fourth and so on.
- 3
- The result of the last combination in the die.der table is in such a way combined that the result is 0 (zero). The number used for this combination is the checksum.
For details look at the source.
METHODS
- is_valid($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.