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Use Skein-256 as PRNG

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Rnhmjoj 2014-10-20 16:54:23 +02:00
parent f396586033
commit da98d65cdd
2 changed files with 2 additions and 19 deletions
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5
Alea/List.hs
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@ -1,10 +1,5 @@
module Alea.List where
-- Remove the nth element of a list. (0-indexed)
-- RemoveAt 2 "abc" == ('c', "ab")
removeAt :: Int -> [a] -> (a, [a])
removeAt n xs = (xs !! n, take n xs ++ drop (n+1) xs)
-- Split a list into a list of lists
-- ex. split ',' "ab,cd,ef" == ["ab","cd","ef"]
split :: (Eq a) => a -> [a] -> [[a]]

16
Alea/Random.hs
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@ -1,18 +1,6 @@
module Alea.Random where
import System.Random
import Alea.List
import Crypto.Threefish.Random
-- Get n random numbers from the list ys
randPick :: (Eq a, RandomGen g) => [a] -> Int -> g -> ([a], g)
randPick [] _ gen = ([], gen)
randPick _ 0 gen = ([], gen)
randPick ys n gen = (x : xs', gen'')
where
(randIndex, gen') = randomR (0, length ys - 1) gen
(x, xs) = removeAt randIndex ys
(xs', gen'') = randPick xs (n-1) gen'
-- Generate k random number in the range [0, n)
randWords :: Int -> Int -> IO [Int]
randWords n k = getStdRandom (randPick [0..n-1] k)
randWords n k = newSkeinGen >>= \x -> return . take k $ randomRs (0, n) x