Algorithm::CheckDigits::MBase_003(3)

NAME
CheckDigits::MBase_003 - compute check digits for SICI (Serial Item and Contribution Identifier)

SYNOPSIS
  use Algorithm::CheckDigits;

  $sici = CheckDigits('sici');

  if ($sici->is_valid('0784-8679(20040308)6:<138>2.0.TX;2-H')) {
        # do something
  }

  $cn = $sici->complete('0784-8679(20040308)6:<138>2.0.TX;2-');
  # $cn = '0784-8679(20040308)6:<138>2.0.TX;2-H'

  $cd = $sici->checkdigit('0784-8679(20040308)6:<138>2.0.TX;2-H');
  # $cd = 'H'

  $bn = $sici->basenumber('0784-8679(20040308)6:<138>2.0.TX;2-H');
  # $bn = '0784-8679(20040308)6:<138>2.0.TX;2-';

DESCRIPTION

  ALGORITHM

0   In the string describing the number all letters (A-Z) are replaced with numbers 10-35 accordingly. All other non-numbers are replaced by 36.

1   Beginning right the numbers at all odd positions are added.

2   The sum from step 1 is multiplied by 3.

3   Beginning right the numbers at all even positions are added.

4   The sums from step 2 and 3 are added.

5   The sum from step 4 is taken modulo 37.

6   The checksum is 37 minus the sum from step 5 where numbers from 10 to 35 are represented by 'A' to 'Z' accordingly and 36 is represented by '#'.

  METHODS

is_valid($number)
    Returns true only if the last letter is a valid check letter according to the algorithm given above.

    Returns false otherwise,

complete($number)
    The check letter for $number is computed and appended the end of $number.

    Returns the complete number with check letter or ''.

basenumber($number)
    Returns the basenumber of $number if $number has a valid check digit.

    Return '' otherwise.

checkdigit($number)
    Returns the check letter of $number if $number has valid check digits.

    Return '' otherwise.

  EXPORT
None by default.

AUTHOR
Mathias Weidner, "<mamawe@cpan.org>"

SEE ALSO
perl, CheckDigits, www.pruefziffernberechnung.de, http://sunsite.berkeley.edu/SICI/sici.pdf