Merge pull request #28 from f-o-a-m/even-hexstrings

Standardize HexString

Author: martyall

src/Network/Ethereum/Core/HexString.purs

@@ -5,9 +5,9 @@ module Network.Ethereum.Core.HexString
   , asSigned
   , mkHexString
   , unHex
-  , hexLength
-  , dropHex
-  , takeHex
+  , numberOfBytes
+  , dropBytes
+  , takeBytes
   , nullWord
   , getPadLength
   , padLeftSigned
@@ -45,7 +45,6 @@ import Network.Ethereum.Core.BigNumber (BigNumber, toString, hexadecimal)
 import Node.Encoding (Encoding(Hex, UTF8, ASCII))
 import Partial.Unsafe (unsafePartial)
 import Simple.JSON (class ReadForeign, class WriteForeign)
-import Text.Parsing.Parser.String (class StringLike)
 
 --------------------------------------------------------------------------------
 -- * Signed Values
@@ -58,13 +57,6 @@ derive instance eqSign :: Eq Sign
 -- | Represents values that can be either positive or negative.
 data Signed a = Signed Sign a
 
-instance showSigned :: Show a => Show (Signed a) where
-  show (Signed s a) = s' <> show a
-    where
-      s' = case s of
-        Pos -> ""
-        Neg -> "-"
-
 instance eqSigned :: Eq a => Eq (Signed a) where
   eq (Signed s a) (Signed s' a') = (s `eq` s') && (a `eq` a')
 
@@ -83,17 +75,13 @@ asSigned a = Signed Pos a
 newtype HexString = HexString String
 
 instance showHexString :: Show HexString where
-  show (HexString hx) = "0x" <> hx
-
-instance hexStringEq :: Eq HexString where
-  eq (HexString h1) (HexString h2) = S.toLower h1 == S.toLower h2
+  show (HexString s) = "0x" <> s 
 
+derive newtype instance hexStringEq :: Eq HexString
 derive newtype instance hexStringOrd :: Ord HexString
 derive newtype instance semigpStringEq :: Semigroup HexString
 derive newtype instance monoidStringEq :: Monoid HexString
 
-derive newtype instance stringLikeHexString :: StringLike HexString
-
 _encode :: HexString -> String
 _encode = append "0x" <<< unHex
 
@@ -147,15 +135,14 @@ mkHexString str | S.length str `mod` 2 /= 0 = Nothing
               then go tail
               else Nothing
 
--- | Compute the length of the hex string, which is twice the number of bytes it represents
-hexLength :: HexString -> Int
-hexLength (HexString hx) = S.length hx
+numberOfBytes :: HexString -> Int
+numberOfBytes (HexString hx) = S.length hx `div` 2
 
-takeHex :: Int -> HexString -> HexString
-takeHex n (HexString hx) = HexString $ S.take n hx
+takeBytes :: Int -> HexString -> HexString
+takeBytes n (HexString hx) = HexString $ S.take (2 * n) hx
 
-dropHex :: Int -> HexString -> HexString
-dropHex n (HexString hx) = HexString $ S.drop n hx
+dropBytes :: Int -> HexString -> HexString
+dropBytes n (HexString hx) = HexString $ S.drop (2 * n) hx
 
 nullWord :: HexString
 nullWord = HexString "0000000000000000000000000000000000000000000000000000000000000000"
@@ -168,23 +155,23 @@ nullWord = HexString "0000000000000000000000000000000000000000000000000000000000
 -- | Computes the number of 0s needed to pad a bytestring of the input length
 getPadLength :: Int -> Int
 getPadLength len =
-  let n = len `mod` 64
-  in if n == 0 then 0 else 64 - n
+  let n = len `mod` 32
+  in if n == 0 then 0 else 32 - n
 
 -- | Pad a `Signed HexString` on the left until it has length == 0 mod 64.
 padLeftSigned :: Signed HexString -> HexString
 padLeftSigned (Signed s hx) =
-    let padLength = getPadLength $ hexLength hx
+    let padLength = getPadLength $ numberOfBytes hx
         sgn = if s `eq` Pos then '0' else 'f'
-        padding = unsafePartial fromJust <<< mkHexString <<< fromCharArray <<< replicate padLength $ sgn
+        padding = unsafePartial fromJust <<< mkHexString <<< fromCharArray <<< replicate (2 * padLength) $ sgn
     in padding <> hx
 
 -- | Pad a `Signed HexString` on the right until it has length 0 mod 64.
 padRightSigned :: Signed HexString -> HexString
 padRightSigned (Signed s hx) =
-    let padLength = getPadLength $ hexLength hx
+    let padLength = getPadLength $ numberOfBytes hx
         sgn = if s `eq` Pos then '0' else 'f'
-        padding = unsafePartial fromJust <<< mkHexString <<< fromCharArray <<< replicate padLength $ sgn
+        padding = unsafePartial fromJust <<< mkHexString <<< fromCharArray <<< replicate (2 * padLength) $ sgn
     in hx <> padding
 
 -- | Pad a `HexString` on the left with '0's until it has length == 0 mod 64.

src/Network/Ethereum/Core/Keccak256.purs

@@ -8,7 +8,7 @@ import Prelude
 
 import Data.ByteString (ByteString, fromString)
 import Data.Maybe (fromJust)
-import Network.Ethereum.Core.HexString (HexString, fromByteString, takeHex, toByteString)
+import Network.Ethereum.Core.HexString (HexString, fromByteString, takeBytes, toByteString)
 import Node.Encoding (Encoding(UTF8))
 import Partial.Unsafe (unsafePartial)
 
@@ -32,4 +32,4 @@ instance keccak256HexString :: Keccak256 HexString where
 
 -- | convert a string representing a type signature into a selector
 toSelector :: String -> HexString
-toSelector = takeHex 8 <<< fromByteString <<< keccak256
+toSelector = takeBytes 4 <<< fromByteString <<< keccak256

src/Network/Ethereum/Core/Signatures.purs

@@ -35,7 +35,7 @@ import Data.Maybe (Maybe(..), fromJust)
 import Effect (Effect)
 import Foreign (ForeignError(..), fail)
 import Foreign.Class (class Decode, class Encode, decode, encode)
-import Network.Ethereum.Core.HexString (HexString, takeHex, nullWord, dropHex, hexLength, toByteString, fromByteString)
+import Network.Ethereum.Core.HexString (HexString, takeBytes, nullWord, dropBytes, numberOfBytes, toByteString, fromByteString)
 import Network.Ethereum.Core.Keccak256 (keccak256)
 import Partial.Unsafe (unsafePartial)
 import Simple.JSON (class ReadForeign, class WriteForeign)
@@ -140,10 +140,10 @@ unAddress :: Address -> HexString
 unAddress (Address a) = a
 
 mkAddress :: HexString -> Maybe Address
-mkAddress hx = if hexLength hx == 40 then Just <<< Address $ hx else Nothing
+mkAddress hx = if numberOfBytes hx == 20 then Just <<< Address $ hx else Nothing
 
 nullAddress :: Address
-nullAddress = Address $ takeHex 40 nullWord
+nullAddress = Address $ takeBytes 20 nullWord
 
 -- | Produce the `Address` corresponding to the `PrivateKey`.
 privateToAddress
@@ -157,7 +157,7 @@ publicToAddress
   -> Address
 publicToAddress (PublicKey publicKey) =
   let addrHex = fromByteString $ keccak256 publicKey
-  in unsafePartial fromJust <<< mkAddress $ dropHex 24 addrHex
+  in unsafePartial fromJust <<< mkAddress $ dropBytes 12 addrHex
 
 newtype Signature =
   Signature { r :: HexString