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NAME

CheckDigits::MXX_001 - compute check digits for german Personalausweis (pa_de) or ABA routing numbers (aba_rn)

SYNOPSIS

use Algorithm::CheckDigits;

\$pa = CheckDigits('pa_de');

if (\$pa->is_valid('2406055684D<<6810203<0705109<6')) {
# do something
}

if (\$pa->is_valid('2406055684') {
# do_something
}

\$cn = \$pa->complete('240605568_D<<681020_<070510_<_');
# \$cn = '2406055684D<<6810203<0705109<6'

\$cd = \$pa->checkdigit('2406055684D<<6810203<0705109<6');
# \$cd = '6'

\$bn = \$pa->basenumber('2406055684D<<6810203<0705109<6');
# \$bn = '240605568_D<<681020_<070510_<_'

\$aba = CheckDigits('aba_rn');
if (\$aba->is_valid('789456124')) {
# do something
}

DESCRIPTION

ALGORITHM

1. Beginning left all digits are weighted with 7,3,1,7,3,1,... for pa_de or 3,7,1,3,7,1,3,7,1 for aba_rn.

2. The sum of those products is computed.

3. For pa_de the checksum is the last digit of the sum from step 2 (modulo 10).

For aba_rn the checksum is the difference of the sum from step 2 to the next multiple of 10.

4. For the german Personalausweis step 1 to 3 is performed for every part of the number and for all 3 parts including the particular checkdigit to compute the total checksum.

If the number solely consists of digits, the checksum is just computed once according to algorithm given above.

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.

None by default.

AUTHOR

Mathias Weidner, <mamawe@cpan.org>

THANKS

Aaron W. West pointed me to a fault in the computing of the check digit. Jim Hickstein made me aware of the ABA routing numbers.