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25 lines
760 B
25 lines
760 B
(def- DEFAULT_ALPHABET "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
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(def- masks [15 31 63 127 255])
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(defn gen [&keys {:size size
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:alphabet alphabet}]
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(default size 21)
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(default alphabet DEFAULT_ALPHABET)
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(def mask (find |(>= $ (dec (length alphabet))) masks))
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(def step (->> alphabet
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(length)
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(/ (* 1.6 mask size))
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(math/ceil)))
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(def result (array/new size))
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(while (> size (length result))
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(loop [byte :in (os/cryptorand step)
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:when (> size (length result))]
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(let [mask-byte (band mask byte)
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char (get alphabet mask-byte)]
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(if char
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(array/push result char))
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)))
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(string/from-bytes ;result))
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