{- arch-tag: Bit utilities main file Copyright (C) 2004-2005 John Goerzen <jgoerzen@complete.org> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA -} {- | Module : Data.Bits.Utils Copyright : Copyright (C) 2004-2005 John Goerzen License : GNU GPL, version 2 or above Maintainer : John Goerzen <jgoerzen@complete.org> Stability : provisional Portability: portable to platforms with rawSystem Bit-related utilities Written by John Goerzen, jgoerzen\@complete.org -} module Data.Bits.Utils(getBytes, fromBytes, c2w8, s2w8, w82c, w82s) where import Data.Bits import Data.Word {- | Returns a list representing the bytes that comprise a data type. Example: > getBytes (0x12345678::Int) -> [0x12, 0x34, 0x56, 0x78] -} getBytes :: (Integral a, Bounded a, Bits a) => a -> [a] getBytes input = let getByte _ 0 = [] getByte x remaining = (x .&. 0xff) : getByte (shiftR x 8) (remaining - 1) in if (bitSize input `mod` 8) /= 0 then error "Input data bit size must be a multiple of 8" else reverse $ getByte input (bitSize input `div` 8) {- | The opposite of 'getBytes', this function builds a number based on its component bytes. Results are undefined if any components of the input list are > 0xff! -} fromBytes :: (Bits a) => [a] -> a fromBytes input = let dofb accum [] = accum dofb accum (x:xs) = dofb ((shiftL accum 8) .|. x) xs in dofb 0 input {- | Converts a Char to a Word8. -} c2w8 :: Char -> Word8 c2w8 = fromIntegral . fromEnum {- | Converts a String to a [Word8]. -} s2w8 :: String -> [Word8] s2w8 = map c2w8 {- | Converts a Word8 to a Char. -} w82c :: Word8 -> Char w82c = toEnum . fromIntegral {- | Converts a [Word8] to a String. -} w82s :: [Word8] -> String w82s = map w82c