1Algorithm::CheckDigits:U:sMe1r1_C0o0n1t(r3i)buted Perl DAolcguomreintthamt:i:oCnheckDigits::M11_001(3)
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6 CheckDigits::M11_001 - compute check digits for ISBN, ISSN, VAT RN
7 (PT), HKID (HK), Wagon number (BR), NHS (GB), VAT (SL)
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10 use Algorithm::CheckDigits;
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12 $isbn = CheckDigits('isbn');
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14 if ($isbn->is_valid('3-88229-192-3')) {
15 # do something
16 }
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18 $cn = $isbn->complete('3-88229-192-');
19 # $cn = '3-88229-192-3'
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21 $cd = $isbn->checkdigit('3-88229-192-3');
22 # $cd = '3'
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24 $bn = $isbn->basenumber('3-88229-192-3');
25 # $bn = '3-88229-192-'
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28 ALGORITHM
29 1. The sequence of digits is processed right to left. Every digit is
30 multiplied with their position in the sequence (i.e. the digit
31 left to the check digit has the weight 2 then 3 etc.).
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33 With a Hongkong ID (hkid) the leftmost char is replaced with its
34 position in the alphabet and then multiplied with 8 (its weight).
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36 2. The sum of all products is computed.
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38 3. The sum of step 2 is taken modulo 11.
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40 4. The checkdigit is the difference of the sum from step 3 to eleven
41 under the following conditions:
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43 isbn,issn
44 If the difference is 10, the check digit is 'X'.
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46 If the difference is 11, the check digit is 0.
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48 ustid_pt
49 If the difference is greater then 9, the check digit is
50 '0'.
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52 hkid If the difference is 10, the check digit is 'A'.
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54 If the difference is 11, the check digit is 0.
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56 wagonnr_br
57 If the difference is 10, the check digit is 0.
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59 If the difference is 11, the check digit is 1.
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61 nhs_gb If the difference is 10, the number would not be taken.
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63 If the difference is 11, the check digit is 0.
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65 vat_sl This is a little bit unclear, don't trust on the method for
66 this type.
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68 METHODS
69 is_valid($number)
70 Returns true only if $number consists solely of numbers and the
71 last digit is a valid check digit according to the algorithm given
72 above.
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74 Returns false otherwise,
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76 complete($number)
77 The check digit for $number is computed and concatenated to the end
78 of $number.
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80 Returns the complete number with check digit or '' if $number does
81 not consist solely of digits and spaces.
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83 basenumber($number)
84 Returns the basenumber of $number if $number has a valid check
85 digit.
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87 Return '' otherwise.
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89 checkdigit($number)
90 Returns the checkdigit of $number if $number has a valid check
91 digit.
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93 Return '' otherwise.
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95 EXPORT
96 None by default.
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99 Mathias Weidner, "<mamawe@cpan.org>"
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102 perl, CheckDigits, www.pruefziffernberechnung.de.
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106perl v5.32.1 2021-01-26Algorithm::CheckDigits::M11_001(3)