54 lines
1.5 KiB
Haskell
54 lines
1.5 KiB
Haskell
{- Simple Base64 encoding
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-
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- Copyright 2011-2019 Joey Hess <id@joeyh.name>
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-
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- License: BSD-2-clause
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-}
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{-# LANGUAGE PackageImports #-}
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module Utility.Base64 where
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import Utility.FileSystemEncoding
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import Utility.QuickCheck
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import qualified "sandi" Codec.Binary.Base64 as B64
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import Data.Maybe
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import qualified Data.ByteString as B
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import Data.ByteString.UTF8 (fromString, toString)
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import Data.Char
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-- | This uses the FileSystemEncoding, so it can be used on Strings
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-- that represent filepaths containing arbitrarily encoded characters.
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toB64 :: String -> String
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toB64 = toString . B64.encode . encodeBS
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toB64' :: B.ByteString -> B.ByteString
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toB64' = B64.encode
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fromB64Maybe :: String -> Maybe String
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fromB64Maybe s = either (const Nothing) (Just . decodeBS)
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(B64.decode $ fromString s)
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fromB64Maybe' :: B.ByteString -> Maybe (B.ByteString)
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fromB64Maybe' = either (const Nothing) Just . B64.decode
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fromB64 :: String -> String
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fromB64 = fromMaybe bad . fromB64Maybe
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where
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bad = error "bad base64 encoded data"
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fromB64' :: B.ByteString -> B.ByteString
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fromB64' = fromMaybe bad . fromB64Maybe'
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where
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bad = error "bad base64 encoded data"
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-- Only ascii strings are tested, because an arbitrary string may contain
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-- characters not encoded using the FileSystemEncoding, which would thus
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-- not roundtrip, as decodeBS always generates an output encoded that way.
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prop_b64_roundtrips :: TestableString -> Bool
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prop_b64_roundtrips ts
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| all (isAscii) s = s == decodeBS (fromB64' (toB64' (encodeBS s)))
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| otherwise = True
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where
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s = fromTestableString ts
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