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CheckDigits::M16_001 - compute check digits for ISAN

 CheckDigits::M16_001(3pm) User Contributed Perl Documentation CheckDigits::M16_001(3pm)

NAME

CheckDigits::M16_001 - compute check digits for ISAN

SYNOPSIS

use Algorithm::CheckDigits;
\$isan = CheckDigits('isan');
if (\$isan->is_valid('123A567B8912E01A')) {
# do something
}
\$cn = \$isan->complete('123A567B8912E01');
# \$cn = '123A567B8912E01A'
\$cd = \$isan->checkdigit('123A567B8912E01A');
# \$cd = '4'
\$bn = \$isan->basenumber('123A567B8912E01A');
# \$bn = '123A567B8912E01'

DESCRIPTION

ALGORITHM

1.
"a(1) = 16"

"b(i) = a(i) % 17 +d(i)", where d(i) is the decimal value of the hexdigit at position i.

"c(i) = b(i) % 16"

"a(i) = c(i-1) * 2", for i greater than 1
2.
Beginning left for each i = 1..16, "a", "b", "c" are computed.
3.
The check digit is the value for "d(16)" where "c(16)" equals 1.
4.
The check digit is appended as hexadecimal value to the number.

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.