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42 lines
1.2 KiB
42 lines
1.2 KiB
(def- DEFAULT_ALPHABET "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
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(def- DEFAULT_RNG (math/rng (os/time)))
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(def- masks [15 31 63 127 255])
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(defn gen
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"Generate secure random ID. Default size of 21."
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[&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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(let [mask (find |(>= $ (dec (length alphabet))) masks)
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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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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 (array/push result char)))))
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(string/from-bytes ;result)))
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(defn gen-non-secure
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"Generate pseudorandom ID. Default size of 21."
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[&keys {:size size
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:alphabet alphabet
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:rng rng}]
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(default size 21)
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(default alphabet DEFAULT_ALPHABET)
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(default rng DEFAULT_RNG)
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(string/from-bytes
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;(seq [i :range [0 size]]
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(get alphabet (math/rng-int rng (length alphabet))))))
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