57 lines
1.7 KiB
Plaintext
57 lines
1.7 KiB
Plaintext
import "./fmt" for Fmt
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var d = [
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 0, 6, 7, 8, 9, 5],
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[2, 3, 4, 0, 1, 7, 8, 9, 5, 6],
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[3, 4, 0, 1, 2, 8, 9, 5, 6, 7],
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[4, 0, 1, 2, 3, 9, 5, 6, 7, 8],
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[5, 9, 8, 7, 6, 0, 4, 3, 2, 1],
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[6, 5, 9, 8, 7, 1, 0, 4, 3, 2],
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[7, 6, 5, 9, 8, 2, 1, 0, 4, 3],
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[8, 7, 6, 5, 9, 3, 2, 1, 0, 4],
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[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
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]
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var inv = [0, 4, 3, 2, 1, 5, 6, 7, 8, 9]
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var p = [
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 5, 7, 6, 2, 8, 3, 0, 9, 4],
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[5, 8, 0, 3, 7, 9, 6, 1, 4, 2],
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[8, 9, 1, 6, 0, 4, 3, 5, 2, 7],
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[9, 4, 5, 3, 1, 2, 6, 8, 7, 0],
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[4, 2, 8, 6, 5, 7, 3, 9, 0, 1],
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[2, 7, 9, 3, 8, 0, 6, 4, 1, 5],
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[7, 0, 4, 6, 9, 1, 3, 2, 5, 8]
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]
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var verhoeff = Fn.new { |s, validate, table|
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if (table) {
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System.print("%(validate ? "Validation" : "Check digit") calculations for '%(s)':\n")
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System.print(" i nᵢ p[i,nᵢ] c")
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System.print("------------------")
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}
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if (!validate) s = s + "0"
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var c = 0
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var le = s.count - 1
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for (i in le..0) {
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var ni = s[i].bytes[0] - 48
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var pi = p[(le-i) % 8][ni]
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c = d[c][pi]
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if (table) Fmt.print("$2d $d $d $d", le-i, ni, pi, c)
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}
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if (table && !validate) System.print("\ninv[%(c)] = %(inv[c])")
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return !validate ? inv[c] : c == 0
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}
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var sts = [["236", true], ["12345", true], ["123456789012", false]]
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for (st in sts) {
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var c = verhoeff.call(st[0], false, st[1])
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System.print("\nThe check digit for '%(st[0])' is '%(c)'\n")
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for (stc in [st[0] + c.toString, st[0] + "9"]) {
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var v = verhoeff.call(stc, true, st[1])
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System.print("\nThe validation for '%(stc)' is %(v ? "correct" : "incorrect").\n")
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}
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}
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