Algorithm::CheckDigits::M10_003(3pm)

NAME

CheckDigits::M10_003 - compute check digits for ISMN

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.

EXPORT

None by default.

AUTHOR

Mathias Weidner, "<[email protected]>"