Updates interface to make a lot more generic

We now make use of the Binary interface, instead of relying on the
caller to provide ByteString objects himself.
This commit is contained in:
Leon Mergen 2015-04-20 16:26:56 +07:00
parent 6eea89845d
commit ff3cab38d9
2 changed files with 51 additions and 55 deletions

View file

@ -1,57 +1,48 @@
module Data.HexString ( HexString (..)
, decodeText
, decodeString
, encodeText
, encodeString ) where
module Data.HexString ( HexString
, hexString
, toHex
, fromHex
, asText ) where
import Control.Applicative ((<$>))
import Data.Word (Word8)
import qualified Data.ByteString.Base16.Lazy as BS16L (decode, encode)
import qualified Data.ByteString.Lazy.Char8 as BSL8
import qualified Data.ByteString.Base16 as BS16 (decode, encode)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Lazy as BSL
import qualified Data.Text as T
import qualified Data.Text.Encoding as TE
import qualified Data.Binary as B (Binary, decode, encode, get,
put)
import qualified Data.Binary.Get as B (getRemainingLazyByteString)
import qualified Data.Binary.Put as B (putLazyByteString)
import qualified Data.Binary as B (Binary, decode, encode)
-- | Data type representing a HexString.
data HexString
= HexString BSL.ByteString
-- | Represents a Hex string. Guarantees that all characters it contains
-- are valid hex characters.
data HexString =
HexString BS.ByteString
deriving ( Show, Eq, Ord )
-- | Allows us to convert to and from a `B.Binary` representation. Always
-- assumes that the entire binary string that is fed to `Binary.decode`
-- represents the hex string.
instance B.Binary HexString where
get = HexString <$> B.getRemainingLazyByteString
put (HexString bs) = B.putLazyByteString bs
-- | Smart constructor which validates that all the text are actually
-- hexadecimal characters.
hexString :: BS.ByteString -> HexString
hexString bs =
let isValidHex :: Word8 -> Bool
isValidHex c
| (48 <= c) && (c < 58) = True
| (97 <= c) && (c < 103) = True
| otherwise = False
-- | Converts a `T.Text` representation to a `HexString`
decodeText :: T.Text -> HexString
decodeText = decodeByteString . BSL.fromStrict . TE.encodeUtf8
in if BS.all isValidHex bs
then (HexString bs)
else error ("Not a valid hex string: " ++ show bs)
-- | Converts a `String` representation to a `HexString`
decodeString :: String -> HexString
decodeString = decodeByteString . BSL8.pack
-- | Converts a 'B.Binary' to a 'HexString' value
toHex :: B.Binary a => a -> HexString
toHex = hexString . BS16.encode . BSL.toStrict . B.encode
-- | Converts a `HexString` to a `T.Text` representation
encodeText :: HexString -> T.Text
encodeText = TE.decodeUtf8 . BSL.toStrict . encodeByteString
-- | Converts a 'HexString' to a 'B.Binary' value
fromHex :: B.Binary a => HexString -> a
fromHex (HexString bs) = B.decode . BSL.fromStrict . fst . BS16.decode $ bs
-- | Converts a `HexString` to a `String` representation
encodeString :: HexString -> String
encodeString = BSL8.unpack . encodeByteString
-- | Internal function that converts a `HexString` to a `BSL.ByteString`
encodeByteString :: HexString -> BSL.ByteString
encodeByteString = BS16L.encode . B.encode
-- | Internal funcion that converts `BSL.ByteString` to a `HexString`
decodeByteString :: BSL.ByteString -> HexString
decodeByteString = B.decode . fst . BS16L.decode
-- | Access to a 'T.Text' representation of the 'HexString'
asText :: HexString -> T.Text
asText (HexString bs) = TE.decodeUtf8 bs

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@ -1,8 +1,12 @@
module Data.HexStringSpec where
import Data.HexString
import Data.HexString ( hexString
, toHex
, fromHex
, asText )
import qualified Data.ByteString.Lazy.Char8 as BSL8
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BS8
import qualified Data.Text as T
import qualified Data.Binary as B ( encode )
@ -11,11 +15,12 @@ import Test.Hspec
spec :: Spec
spec = do
describe "when decoding hex data" $ do
it "should be able to parse basic hex data" $ do
(B.encode . decodeString) "ffff" `shouldBe` BSL8.pack "\255\255"
(B.encode . decodeText) (T.pack "ffff") `shouldBe` BSL8.pack "\255\255"
describe "when constructing a hex string" $ do
it "should accept strings that fall within a valid range" $
hexString (BS8.pack "0123456789abcdef") `shouldBe` hexString (BS8.pack "0123456789abcdef")
it "should be able to recode basic hex data to different formats" $ do
(encodeText . decodeString) "ffff" `shouldBe` T.pack "ffff"
(encodeString . decodeString) "ffff" `shouldBe` "ffff"
it "should reject strings outside the range" $ do
putStrLn (show (hexString (BS8.pack "/"))) `shouldThrow` anyErrorCall
putStrLn (show (hexString (BS8.pack ":"))) `shouldThrow` anyErrorCall
putStrLn (show (hexString (BS8.pack "`"))) `shouldThrow` anyErrorCall
putStrLn (show (hexString (BS8.pack "g"))) `shouldThrow` anyErrorCall