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91 lines
2.1 KiB
91 lines
2.1 KiB
(def DEFAULT_ALPHABET "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
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(def DEFAULT_SEPS "cfhistuCFHISTU")
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(def DEFAULT_SALT "")
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(def DEFAULT_MIN_LENGTH 0)
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(def MIN_ALPHABET_LENGTH 16)
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(def SEP_DIV (/ 7 2))
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(def GUARD_DIV 12)
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(def DEFAULTS {:salt DEFAULT_SALT
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:min-length DEFAULT_MIN_LENGTH
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:alphabet DEFAULT_ALPHABET
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:seps DEFAULT_SEPS})
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(defn- map-indexed [f xs]
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(map f xs (range 0 (length xs))))
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(defn- int-hash [num i]
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(mod num (+ 100 i)))
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(defn- as-indexed [x]
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(if (indexed? x) x [x]))
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(defn- swap [arr i j]
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(def a (in arr j))
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(def b (in arr i))
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(put arr i a)
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(put arr j b)
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)
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(defn- difference [s1 s2]
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(seq [x :in s1 :when (not (find |(= x $) s2))] x))
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(defn- intersection [s1 s2]
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(seq [x :in s1 y :in s2 :when (= x y)] x))
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(defn balance [alph-bytes seps-bytes]
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[
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]
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)
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(defn consistent-shuffle [alph-bytes salt-bytes]
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(if (empty? salt-bytes) alph-bytes
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(let [alph-array (apply array alph-bytes)
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max-index (- (length alph-array) 1)]
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(var p 0)
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(loop [i :down [max-index 0]]
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(let [v (mod (- max-index i) (length salt-bytes))
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n (get salt-bytes v)
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j (mod (+ n v (set p (+ p n))) i)]
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(swap alph-array i j)))
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alph-array)))
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(defn setup [opts]
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(let [{:salt salt
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:alphabet alphabet
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:seps seps
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:min-length min-length} (merge DEFAULTS opts)
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alph-bytes (string/bytes alphabet)
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salt-bytes (string/bytes salt)
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seps-bytes (string/bytes seps)
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alph-unbal (difference alph-bytes seps-bytes)
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seps-unbal (intersection alph-bytes seps-bytes)
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[seps-bal alph-bal] (balance alph-unbal
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(consistent-shuffle seps-unbal salt-bytes))]
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{
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:seps (apply string/from-bytes seps-unbal)
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:alph (apply string/from-bytes alph-unbal)
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:salt salt
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:min-length min-length
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}))
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(defn encode
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"Convert nums to hashids encoded form"
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[source & opts]
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(let [config (setup (table ;opts))
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nums (as-indexed source)
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hash-int (reduce + 0 (map-indexed int-hash nums))]
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(pp config)
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"j0gW"))
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