module Blockchain.Data.Util
  ( byteString2Integer
  , bytes2Integer
  , integer2Bytes
  ) where

import Data.Bits
import qualified Data.ByteString as B
import Data.Word

--I hate this, it is an ugly way to create an Integer from its component bytes.
--There should be an easier way....
--See http://stackoverflow.com/questions/25854311/efficient-packing-bytes-into-integers
byteString2Integer :: B.ByteString -> Integer
byteString2Integer x = bytes2Integer $ B.unpack x

bytes2Integer :: [Word8] -> Integer
bytes2Integer [] = 0
bytes2Integer (byte:rest) =
  fromIntegral byte `shift` (8 * length rest) + bytes2Integer rest

integer2Bytes :: Integer -> [Word8]
integer2Bytes 0 = []
integer2Bytes x = integer2Bytes (x `shiftR` 8) ++ [fromInteger (x .&. 255)]