Long.hs

{-# LANGUAGE ScopedTypeVariables #-}

module Numeric.Long
  ( showLongHex
  , showLongBin
  , showPrefix
  ) where

import           Data.Bits
import           Data.Char



showLongHex :: (FiniteBits a, Integral a, Num a) => a -> ShowS
showLongHex (w0 :: a) = go w0 0
  where
    go w n
      | n >= finiteBitSize (0 :: a) = id
      | otherwise                   =
          let (q, r) = quotRem w 16
          in go q (n + 4 :: Int) . showChar (intToDigit (fromIntegral r))



showLongBin :: (FiniteBits a, Integral a, Num a) => a -> ShowS
showLongBin (w :: a) = go 0
  where
    go n
      | n >= finiteBitSize (0 :: a) = id
      | otherwise                   =
          go (n + 1) . showChar (chr . fromIntegral $ 48 + (unsafeShiftR w n .&. 1))



showPrefix :: (FiniteBits a, Integral a, Num a) => a -> ShowS
showPrefix (w :: a) = go 0
  where
    m = w .&. negate w

    go n
      | n >= finiteBitSize (0 :: a) = id
      | otherwise                   =
          go (n + 1) . showChar
                         ( if unsafeShiftL 1 n >= m
                             then chr . fromIntegral $ 48 + (unsafeShiftR w n .&. 1)
                             else 'X'
                         )