Algorithm::CheckDigits::M16_001 (3pm)

  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'

\s-1ALGORITHM\s0

1.

\*(C`a(1) = 16\*(C' \*(C`b(i) = a(i) % 17 +d(i)\*(C', where d(i) is the decimal value of the hexdigit at position i. \*(C`c(i) = b(i) % 16\*(C' \*(C`a(i) = c(i-1) * 2\*(C', for i greater than 1

2.

Beginning left for each i = 1..16, \*(C`a\*(C', \*(C`b\*(C', \*(C`c\*(C' are computed.

3.

The check digit is the value for \*(C`d(16)\*(C' where \*(C`c(16)\*(C' equals 1.

4.

The check digit is appended as hexadecimal value to the number.

\s-1METHODS\s0

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.

\s-1EXPORT\s0

None by default.

Mathias Weidner, <[email protected]>

perl, CheckDigits, www.pruefziffernberechnung.de.