{-# LANGUAGE CPP, MagicHash, TypeSynonymInstances, FlexibleInstances #-}

{- |
  Module      :  Codec.Binary.UTF8.Light.Helper
  Copyright   :  (c) Francesco Ariis 2022
  License     :  BSD3
  Maintainer  :  Francesco Ariis <fa-ml@ariis.it>
  Stability   :  provisional
  Portability :  portable

  Lightweight UTF8 handling, helper functions.
-}

module Codec.Binary.UTF8.Light.Helper (
            c2w, w2c, i2w, w2i, cwrd, wh, toW8
) where

import GHC.Exts (Int(I#), Char(C#))
import GHC.Word (Word8(W8#), Word32(W32#))
import GHC.Prim (Word#, ord#, chr#, word2Int#, int2Word#)

-----------------------------------------------------------------------------
-- Helper functions for GHC < 9.2

{-# INLINE w2c #-}
w2c :: Word32 -> Char
w2c (W32# w) = C#(chr#(word2Int# w))

{-# INLINE c2w #-}
c2w :: Char -> Word32
c2w (C# c) = W32#(int2Word#(ord# c))

{-# INLINE i2w #-}
i2w :: Int -> Word32
i2w (I# i) = W32#(int2Word# i)

{-# INLINE w2i #-}
w2i :: Word32 -> Int
w2i (W32# w) = I#(word2Int# w)

{-# INLINE wh #-}
wh :: Word# -> Word8
wh w = W8# w

{-# INLINE toW8 #-}
toW8 :: Word# -> Word8
toW8 w = W8# w

{-# INLINE cwrd #-}
cwrd :: Word# -> Word#
cwrd w = w