50 lines
1.6 KiB
Haskell
50 lines
1.6 KiB
Haskell
{-# LANGUAGE PackageImports #-}
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module Database(
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Database,
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emptyDatabase,
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generateNum, genSign
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)
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where
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import "crypto-api" Crypto.Random(CryptoRandomGen(..),SystemRandom)
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import "cryptonite" Crypto.Random(DRG(..))
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import Data.ByteArray(convert)
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import Data.Bits(shiftL,testBit)
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import qualified Data.ByteString as S
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import Data.Map.Strict(Map)
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import qualified Data.Map.Strict as Map
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type Database = (Map String [Integer], SystemRandom)
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instance DRG SystemRandom where
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randomBytesGenerate x g =
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case genBytes x g of
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Left e -> error ("Data generation error: " ++ show e)
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Right (res, g') -> (convert res, g')
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emptyDatabase :: SystemRandom -> Database
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emptyDatabase g0 = (Map.empty, g0)
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generateNum :: Database -> String -> Int -> (Integer, Database)
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generateNum (db, rng0) varname size =
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let (x, rng1) = randomBytesGenerate (size `div` 8) rng0
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x' = integerize x
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before = Map.findWithDefault [] varname db
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in if length (filter (== x') before) < 10
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then (x', (Map.insert varname (x':before) db, rng1))
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else generateNum (db, rng1) varname size
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genSign :: (Integer, Database) -> (Integer, Database)
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genSign (x, (db, rng0)) =
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let (n, rng1) = randomBytesGenerate 1 rng0
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n' = integerize n
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in if testBit n' 0 then (0 - x, (db, rng1)) else (x, (db, rng1))
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integerize :: S.ByteString -> Integer
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integerize = go 0
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where
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go acc bstr =
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case S.uncons bstr of
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Nothing -> acc
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Just (v,rest) ->
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go ((acc `shiftL` 8) + fromIntegral v) rest |