{-# LANGUAGE Safe #-} {-# LANGUAGE NoImplicitPrelude #-} ----------------------------------------------------------------------------- -- | -- Module : Data.Word -- Copyright : (c) The University of Glasgow 2001 -- License : BSD-style (see the file libraries/base/LICENSE) -- -- Maintainer : libraries@haskell.org -- Stability : stable -- Portability : portable -- -- Unsigned integer types. -- ----------------------------------------------------------------------------- module Data.Word ( -- * Unsigned integral types Word, Word8, Word16, Word32, Word64, -- * byte swapping byteSwap16, byteSwap32, byteSwap64, -- * bit reversal bitReverse8, bitReverse16, bitReverse32, bitReverse64 -- * Notes -- $notes ) where import GHC.Word import GHC.Read () -- Need the `Read` instance for types defined in `GHC.Word`. {- $notes * All arithmetic is performed modulo 2^n, where n is the number of bits in the type. One non-obvious consequence of this is that 'Prelude.negate' should /not/ raise an error on negative arguments. * For coercing between any two integer types, use 'Prelude.fromIntegral', which is specialized for all the common cases so should be fast enough. Coercing word types to and from integer types preserves representation, not sign. * An unbounded size unsigned integer type is available with 'Numeric.Natural.Natural'. * The rules that hold for 'Prelude.Enum' instances over a bounded type such as 'Prelude.Int' (see the section of the Haskell report dealing with arithmetic sequences) also hold for the 'Prelude.Enum' instances over the various 'Word' types defined here. * Right and left shifts by amounts greater than or equal to the width of the type result in a zero result. This is contrary to the behaviour in C, which is undefined; a common interpretation is to truncate the shift count to the width of the type, for example @1 \<\< 32 == 1@ in some C implementations. -}