{-# OPTIONS_GHC -XNoImplicitPrelude #-}
{-# OPTIONS_HADDOCK hide #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  GHC.Word
-- Copyright   :  (c) The University of Glasgow, 1997-2002
-- License     :  see libraries/base/LICENSE
-- 
-- Maintainer  :  cvs-ghc@haskell.org
-- Stability   :  internal
-- Portability :  non-portable (GHC Extensions)
--
-- Sized unsigned integral types: 'Word', 'Word8', 'Word16', 'Word32', and
-- 'Word64'.
--
-----------------------------------------------------------------------------

#include "MachDeps.h"

-- #hide
module GHC.Word (
    Word(..), Word8(..), Word16(..), Word32(..), Word64(..),
    toEnumError, fromEnumError, succError, predError,
    uncheckedShiftL64#,
    uncheckedShiftRL64#
    ) where

import Data.Bits

#if WORD_SIZE_IN_BITS < 32
import GHC.IntWord32
#endif
#if WORD_SIZE_IN_BITS < 64
import GHC.IntWord64
#endif

import GHC.Base
import GHC.Enum
import GHC.Num
import GHC.Real
import GHC.Read
import GHC.Arr
import GHC.Show

------------------------------------------------------------------------
-- Helper functions
------------------------------------------------------------------------

{-# NOINLINE toEnumError #-}
toEnumError :: (Show a) => String -> Int -> (a,a) -> b
toEnumError inst_ty i bnds =
    error $ "Enum.toEnum{" ++ inst_ty ++ "}: tag (" ++
            show i ++
            ") is outside of bounds " ++
            show bnds

{-# NOINLINE fromEnumError #-}
fromEnumError :: (Show a) => String -> a -> b
fromEnumError inst_ty x =
    error $ "Enum.fromEnum{" ++ inst_ty ++ "}: value (" ++
            show x ++
            ") is outside of Int's bounds " ++
            show (minBound::Int, maxBound::Int)

{-# NOINLINE succError #-}
succError :: String -> a
succError inst_ty =
    error $ "Enum.succ{" ++ inst_ty ++ "}: tried to take `succ' of maxBound"

{-# NOINLINE predError #-}
predError :: String -> a
predError inst_ty =
    error $ "Enum.pred{" ++ inst_ty ++ "}: tried to take `pred' of minBound"

------------------------------------------------------------------------
-- type Word
------------------------------------------------------------------------

-- |A 'Word' is an unsigned integral type, with the same size as 'Int'.
data Word = W# Word# deriving (Eq, Ord)

instance Show Word where
    showsPrec p x = showsPrec p (toInteger x)

instance Num Word where
    (W# x#) + (W# y#)      = W# (x# `plusWord#` y#)
    (W# x#) - (W# y#)      = W# (x# `minusWord#` y#)
    (W# x#) * (W# y#)      = W# (x# `timesWord#` y#)
    negate (W# x#)         = W# (int2Word# (negateInt# (word2Int# x#)))
    abs x                  = x
    signum 0               = 0
    signum _               = 1
    fromInteger i          = W# (integerToWord i)

instance Real Word where
    toRational x = toInteger x % 1

instance Enum Word where
    succ x
        | x /= maxBound = x + 1
        | otherwise     = succError "Word"
    pred x
        | x /= minBound = x - 1
        | otherwise     = predError "Word"
    toEnum i@(I# i#)
        | i >= 0        = W# (int2Word# i#)
        | otherwise     = toEnumError "Word" i (minBound::Word, maxBound::Word)
    fromEnum x@(W# x#)
        | x <= fromIntegral (maxBound::Int)
                        = I# (word2Int# x#)
        | otherwise     = fromEnumError "Word" x
    enumFrom            = integralEnumFrom
    enumFromThen        = integralEnumFromThen
    enumFromTo          = integralEnumFromTo
    enumFromThenTo      = integralEnumFromThenTo

instance Integral Word where
    quot    (W# x#) y@(W# y#)
        | y /= 0                = W# (x# `quotWord#` y#)
        | otherwise             = divZeroError
    rem     (W# x#) y@(W# y#)
        | y /= 0                = W# (x# `remWord#` y#)
        | otherwise             = divZeroError
    div     (W# x#) y@(W# y#)
        | y /= 0                = W# (x# `quotWord#` y#)
        | otherwise             = divZeroError
    mod     (W# x#) y@(W# y#)
        | y /= 0                = W# (x# `remWord#` y#)
        | otherwise             = divZeroError
    quotRem (W# x#) y@(W# y#)
        | y /= 0                = (W# (x# `quotWord#` y#), W# (x# `remWord#` y#))
        | otherwise             = divZeroError
    divMod  (W# x#) y@(W# y#)
        | y /= 0                = (W# (x# `quotWord#` y#), W# (x# `remWord#` y#))
        | otherwise             = divZeroError
    toInteger (W# x#)
        | i# >=# 0#             = smallInteger i#
        | otherwise             = wordToInteger x#
        where
        i# = word2Int# x#

instance Bounded Word where
    minBound = 0

    -- use unboxed literals for maxBound, because GHC doesn't optimise
    -- (fromInteger 0xffffffff :: Word).
#if WORD_SIZE_IN_BITS == 31
    maxBound = W# (int2Word# 0x7FFFFFFF#)
#elif WORD_SIZE_IN_BITS == 32
    maxBound = W# (int2Word# 0xFFFFFFFF#)
#else
    maxBound = W# (int2Word# 0xFFFFFFFFFFFFFFFF#)
#endif

instance Ix Word where
    range (m,n)         = [m..n]
    unsafeIndex (m,_) i = fromIntegral (i - m)
    inRange (m,n) i     = m <= i && i <= n

instance Read Word where
    readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]

instance Bits Word where
    {-# INLINE shift #-}

    (W# x#) .&.   (W# y#)    = W# (x# `and#` y#)
    (W# x#) .|.   (W# y#)    = W# (x# `or#`  y#)
    (W# x#) `xor` (W# y#)    = W# (x# `xor#` y#)
    complement (W# x#)       = W# (x# `xor#` mb#) where W# mb# = maxBound
    (W# x#) `shift` (I# i#)
        | i# >=# 0#          = W# (x# `shiftL#` i#)
        | otherwise          = W# (x# `shiftRL#` negateInt# i#)
    (W# x#) `rotate` (I# i#)
        | i'# ==# 0# = W# x#
        | otherwise  = W# ((x# `uncheckedShiftL#` i'#) `or#` (x# `uncheckedShiftRL#` (wsib -# i'#)))
        where
        i'# = word2Int# (int2Word# i# `and#` int2Word# (wsib -# 1#))
        wsib = WORD_SIZE_IN_BITS#  {- work around preprocessor problem (??) -}
    bitSize  _               = WORD_SIZE_IN_BITS
    isSigned _               = False

    {-# INLINE shiftR #-}
    -- same as the default definition, but we want it inlined (#2376)
    x `shiftR`  i = x `shift`  (-i)

{-# RULES
"fromIntegral/Int->Word"  fromIntegral = \(I# x#) -> W# (int2Word# x#)
"fromIntegral/Word->Int"  fromIntegral = \(W# x#) -> I# (word2Int# x#)
"fromIntegral/Word->Word" fromIntegral = id :: Word -> Word
  #-}

------------------------------------------------------------------------
-- type Word8
------------------------------------------------------------------------

-- Word8 is represented in the same way as Word. Operations may assume
-- and must ensure that it holds only values from its logical range.

data Word8 = W8# Word# deriving (Eq, Ord)
-- ^ 8-bit unsigned integer type

instance Show Word8 where
    showsPrec p x = showsPrec p (fromIntegral x :: Int)

instance Num Word8 where
    (W8# x#) + (W8# y#)    = W8# (narrow8Word# (x# `plusWord#` y#))
    (W8# x#) - (W8# y#)    = W8# (narrow8Word# (x# `minusWord#` y#))
    (W8# x#) * (W8# y#)    = W8# (narrow8Word# (x# `timesWord#` y#))
    negate (W8# x#)        = W8# (narrow8Word# (int2Word# (negateInt# (word2Int# x#))))
    abs x                  = x
    signum 0               = 0
    signum _               = 1
    fromInteger i          = W8# (narrow8Word# (integerToWord i))

instance Real Word8 where
    toRational x = toInteger x % 1

instance Enum Word8 where
    succ x
        | x /= maxBound = x + 1
        | otherwise     = succError "Word8"
    pred x
        | x /= minBound = x - 1
        | otherwise     = predError "Word8"
    toEnum i@(I# i#)
        | i >= 0 && i <= fromIntegral (maxBound::Word8)
                        = W8# (int2Word# i#)
        | otherwise     = toEnumError "Word8" i (minBound::Word8, maxBound::Word8)
    fromEnum (W8# x#)   = I# (word2Int# x#)
    enumFrom            = boundedEnumFrom
    enumFromThen        = boundedEnumFromThen

instance Integral Word8 where
    quot    (W8# x#) y@(W8# y#)
        | y /= 0                  = W8# (x# `quotWord#` y#)
        | otherwise               = divZeroError
    rem     (W8# x#) y@(W8# y#)
        | y /= 0                  = W8# (x# `remWord#` y#)
        | otherwise               = divZeroError
    div     (W8# x#) y@(W8# y#)
        | y /= 0                  = W8# (x# `quotWord#` y#)
        | otherwise               = divZeroError
    mod     (W8# x#) y@(W8# y#)
        | y /= 0                  = W8# (x# `remWord#` y#)
        | otherwise               = divZeroError
    quotRem (W8# x#) y@(W8# y#)
        | y /= 0                  = (W8# (x# `quotWord#` y#), W8# (x# `remWord#` y#))
        | otherwise               = divZeroError
    divMod  (W8# x#) y@(W8# y#)
        | y /= 0                  = (W8# (x# `quotWord#` y#), W8# (x# `remWord#` y#))
        | otherwise               = divZeroError
    toInteger (W8# x#)            = smallInteger (word2Int# x#)

instance Bounded Word8 where
    minBound = 0
    maxBound = 0xFF

instance Ix Word8 where
    range (m,n)         = [m..n]
    unsafeIndex (m,_) i = fromIntegral (i - m)
    inRange (m,n) i     = m <= i && i <= n

instance Read Word8 where
    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]

instance Bits Word8 where
    {-# INLINE shift #-}

    (W8# x#) .&.   (W8# y#)   = W8# (x# `and#` y#)
    (W8# x#) .|.   (W8# y#)   = W8# (x# `or#`  y#)
    (W8# x#) `xor` (W8# y#)   = W8# (x# `xor#` y#)
    complement (W8# x#)       = W8# (x# `xor#` mb#) where W8# mb# = maxBound
    (W8# x#) `shift` (I# i#)
        | i# >=# 0#           = W8# (narrow8Word# (x# `shiftL#` i#))
        | otherwise           = W8# (x# `shiftRL#` negateInt# i#)
    (W8# x#) `rotate` (I# i#)
        | i'# ==# 0# = W8# x#
        | otherwise  = W8# (narrow8Word# ((x# `uncheckedShiftL#` i'#) `or#`
                                          (x# `uncheckedShiftRL#` (8# -# i'#))))
        where
        i'# = word2Int# (int2Word# i# `and#` int2Word# 7#)
    bitSize  _                = 8
    isSigned _                = False

    {-# INLINE shiftR #-}
    -- same as the default definition, but we want it inlined (#2376)
    x `shiftR`  i = x `shift`  (-i)

{-# RULES
"fromIntegral/Word8->Word8"   fromIntegral = id :: Word8 -> Word8
"fromIntegral/Word8->Integer" fromIntegral = toInteger :: Word8 -> Integer
"fromIntegral/a->Word8"       fromIntegral = \x -> case fromIntegral x of W# x# -> W8# (narrow8Word# x#)
"fromIntegral/Word8->a"       fromIntegral = \(W8# x#) -> fromIntegral (W# x#)
  #-}

------------------------------------------------------------------------
-- type Word16
------------------------------------------------------------------------

-- Word16 is represented in the same way as Word. Operations may assume
-- and must ensure that it holds only values from its logical range.

data Word16 = W16# Word# deriving (Eq, Ord)
-- ^ 16-bit unsigned integer type

instance Show Word16 where
    showsPrec p x = showsPrec p (fromIntegral x :: Int)

instance Num Word16 where
    (W16# x#) + (W16# y#)  = W16# (narrow16Word# (x# `plusWord#` y#))
    (W16# x#) - (W16# y#)  = W16# (narrow16Word# (x# `minusWord#` y#))
    (W16# x#) * (W16# y#)  = W16# (narrow16Word# (x# `timesWord#` y#))
    negate (W16# x#)       = W16# (narrow16Word# (int2Word# (negateInt# (word2Int# x#))))
    abs x                  = x
    signum 0               = 0
    signum _               = 1
    fromInteger i          = W16# (narrow16Word# (integerToWord i))

instance Real Word16 where
    toRational x = toInteger x % 1

instance Enum Word16 where
    succ x
        | x /= maxBound = x + 1
        | otherwise     = succError "Word16"
    pred x
        | x /= minBound = x - 1
        | otherwise     = predError "Word16"
    toEnum i@(I# i#)
        | i >= 0 && i <= fromIntegral (maxBound::Word16)
                        = W16# (int2Word# i#)
        | otherwise     = toEnumError "Word16" i (minBound::Word16, maxBound::Word16)
    fromEnum (W16# x#)  = I# (word2Int# x#)
    enumFrom            = boundedEnumFrom
    enumFromThen        = boundedEnumFromThen

instance Integral Word16 where
    quot    (W16# x#) y@(W16# y#)
        | y /= 0                    = W16# (x# `quotWord#` y#)
        | otherwise                 = divZeroError
    rem     (W16# x#) y@(W16# y#)
        | y /= 0                    = W16# (x# `remWord#` y#)
        | otherwise                 = divZeroError
    div     (W16# x#) y@(W16# y#)
        | y /= 0                    = W16# (x# `quotWord#` y#)
        | otherwise                 = divZeroError
    mod     (W16# x#) y@(W16# y#)
        | y /= 0                    = W16# (x# `remWord#` y#)
        | otherwise                 = divZeroError
    quotRem (W16# x#) y@(W16# y#)
        | y /= 0                    = (W16# (x# `quotWord#` y#), W16# (x# `remWord#` y#))
        | otherwise                 = divZeroError
    divMod  (W16# x#) y@(W16# y#)
        | y /= 0                    = (W16# (x# `quotWord#` y#), W16# (x# `remWord#` y#))
        | otherwise                 = divZeroError
    toInteger (W16# x#)             = smallInteger (word2Int# x#)

instance Bounded Word16 where
    minBound = 0
    maxBound = 0xFFFF

instance Ix Word16 where
    range (m,n)         = [m..n]
    unsafeIndex (m,_) i = fromIntegral (i - m)
    inRange (m,n) i     = m <= i && i <= n

instance Read Word16 where
    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]

instance Bits Word16 where
    {-# INLINE shift #-}

    (W16# x#) .&.   (W16# y#)  = W16# (x# `and#` y#)
    (W16# x#) .|.   (W16# y#)  = W16# (x# `or#`  y#)
    (W16# x#) `xor` (W16# y#)  = W16# (x# `xor#` y#)
    complement (W16# x#)       = W16# (x# `xor#` mb#) where W16# mb# = maxBound
    (W16# x#) `shift` (I# i#)
        | i# >=# 0#            = W16# (narrow16Word# (x# `shiftL#` i#))
        | otherwise            = W16# (x# `shiftRL#` negateInt# i#)
    (W16# x#) `rotate` (I# i#)
        | i'# ==# 0# = W16# x#
        | otherwise  = W16# (narrow16Word# ((x# `uncheckedShiftL#` i'#) `or#`
                                            (x# `uncheckedShiftRL#` (16# -# i'#))))
        where
        i'# = word2Int# (int2Word# i# `and#` int2Word# 15#)
    bitSize  _                = 16
    isSigned _                = False

    {-# INLINE shiftR #-}
    -- same as the default definition, but we want it inlined (#2376)
    x `shiftR`  i = x `shift`  (-i)

{-# RULES
"fromIntegral/Word8->Word16"   fromIntegral = \(W8# x#) -> W16# x#
"fromIntegral/Word16->Word16"  fromIntegral = id :: Word16 -> Word16
"fromIntegral/Word16->Integer" fromIntegral = toInteger :: Word16 -> Integer
"fromIntegral/a->Word16"       fromIntegral = \x -> case fromIntegral x of W# x# -> W16# (narrow16Word# x#)
"fromIntegral/Word16->a"       fromIntegral = \(W16# x#) -> fromIntegral (W# x#)
  #-}

------------------------------------------------------------------------
-- type Word32
------------------------------------------------------------------------

#if WORD_SIZE_IN_BITS < 32

data Word32 = W32# Word32#
-- ^ 32-bit unsigned integer type

instance Eq Word32 where
    (W32# x#) == (W32# y#) = x# `eqWord32#` y#
    (W32# x#) /= (W32# y#) = x# `neWord32#` y#

instance Ord Word32 where
    (W32# x#) <  (W32# y#) = x# `ltWord32#` y#
    (W32# x#) <= (W32# y#) = x# `leWord32#` y#
    (W32# x#) >  (W32# y#) = x# `gtWord32#` y#
    (W32# x#) >= (W32# y#) = x# `geWord32#` y#

instance Num Word32 where
    (W32# x#) + (W32# y#)  = W32# (int32ToWord32# (word32ToInt32# x# `plusInt32#` word32ToInt32# y#))
    (W32# x#) - (W32# y#)  = W32# (int32ToWord32# (word32ToInt32# x# `minusInt32#` word32ToInt32# y#))
    (W32# x#) * (W32# y#)  = W32# (int32ToWord32# (word32ToInt32# x# `timesInt32#` word32ToInt32# y#))
    negate (W32# x#)       = W32# (int32ToWord32# (negateInt32# (word32ToInt32# x#)))
    abs x                  = x
    signum 0               = 0
    signum _               = 1
    fromInteger (S# i#)    = W32# (int32ToWord32# (intToInt32# i#))
    fromInteger (J# s# d#) = W32# (integerToWord32# s# d#)

instance Enum Word32 where
    succ x
        | x /= maxBound = x + 1
        | otherwise     = succError "Word32"
    pred x
        | x /= minBound = x - 1
        | otherwise     = predError "Word32"
    toEnum i@(I# i#)
        | i >= 0        = W32# (wordToWord32# (int2Word# i#))
        | otherwise     = toEnumError "Word32" i (minBound::Word32, maxBound::Word32)
    fromEnum x@(W32# x#)
        | x <= fromIntegral (maxBound::Int)
                        = I# (word2Int# (word32ToWord# x#))
        | otherwise     = fromEnumError "Word32" x
    enumFrom            = integralEnumFrom
    enumFromThen        = integralEnumFromThen
    enumFromTo          = integralEnumFromTo
    enumFromThenTo      = integralEnumFromThenTo

instance Integral Word32 where
    quot    x@(W32# x#) y@(W32# y#)
        | y /= 0                    = W32# (x# `quotWord32#` y#)
        | otherwise                 = divZeroError
    rem     x@(W32# x#) y@(W32# y#)
        | y /= 0                    = W32# (x# `remWord32#` y#)
        | otherwise                 = divZeroError
    div     x@(W32# x#) y@(W32# y#)
        | y /= 0                    = W32# (x# `quotWord32#` y#)
        | otherwise                 = divZeroError
    mod     x@(W32# x#) y@(W32# y#)
        | y /= 0                    = W32# (x# `remWord32#` y#)
        | otherwise                 = divZeroError
    quotRem x@(W32# x#) y@(W32# y#)
        | y /= 0                    = (W32# (x# `quotWord32#` y#), W32# (x# `remWord32#` y#))
        | otherwise                 = divZeroError
    divMod  x@(W32# x#) y@(W32# y#)
        | y /= 0                    = (W32# (x# `quotWord32#` y#), W32# (x# `remWord32#` y#))
        | otherwise                 = divZeroError
    toInteger x@(W32# x#