base-4.1.0.0: Basic librariesSource codeContentsIndex
Data.Bits
Portabilityportable
Stabilityexperimental
Maintainerlibraries@haskell.org
Description
This module defines bitwise operations for signed and unsigned integers. Instances of the class Bits for the Int and Integer types are available from this module, and instances for explicitly sized integral types are available from the Data.Int and Data.Word modules.
Synopsis
class Num a => Bits a where
(.&.) :: a -> a -> a
(.|.) :: a -> a -> a
xor :: a -> a -> a
complement :: a -> a
shift :: a -> Int -> a
rotate :: a -> Int -> a
bit :: Int -> a
setBit :: a -> Int -> a
clearBit :: a -> Int -> a
complementBit :: a -> Int -> a
testBit :: a -> Int -> Bool
bitSize :: a -> Int
isSigned :: a -> Bool
shiftL :: a -> Int -> a
shiftR :: a -> Int -> a
rotateL :: a -> Int -> a
rotateR :: a -> Int -> a
Documentation
class Num a => Bits a whereSource

The Bits class defines bitwise operations over integral types.

  • Bits are numbered from 0 with bit 0 being the least significant bit.

Minimal complete definition: .&., .|., xor, complement, (shift or (shiftL and shiftR)), (rotate or (rotateL and rotateR)), bitSize and isSigned.

Methods
(.&.) :: a -> a -> aSource
Bitwise "and"
(.|.) :: a -> a -> aSource
Bitwise "or"
xor :: a -> a -> aSource
Bitwise "xor"
complement :: a -> aSource
Reverse all the bits in the argument
shift :: a -> Int -> aSource

shift x i shifts x left by i bits if i is positive, or right by -i bits otherwise. Right shifts perform sign extension on signed number types; i.e. they fill the top bits with 1 if the x is negative and with 0 otherwise.

An instance can define either this unified shift or shiftL and shiftR, depending on which is more convenient for the type in question.

rotate :: a -> Int -> aSource

rotate x i rotates x left by i bits if i is positive, or right by -i bits otherwise.

For unbounded types like Integer, rotate is equivalent to shift.

An instance can define either this unified rotate or rotateL and rotateR, depending on which is more convenient for the type in question.

bit :: Int -> aSource
bit i is a value with the ith bit set
setBit :: a -> Int -> aSource
x `setBit` i is the same as x .|. bit i
clearBit :: a -> Int -> aSource
x `clearBit` i is the same as x .&. complement (bit i)
complementBit :: a -> Int -> aSource
x `complementBit` i is the same as x `xor` bit i
testBit :: a -> Int -> BoolSource
Return True if the nth bit of the argument is 1
bitSize :: a -> IntSource
Return the number of bits in the type of the argument. The actual value of the argument is ignored. The function bitSize is undefined for types that do not have a fixed bitsize, like Integer.
isSigned :: a -> BoolSource
Return True if the argument is a signed type. The actual value of the argument is ignored
shiftL :: a -> Int -> aSource

Shift the argument left by the specified number of bits (which must be non-negative).

An instance can define either this and shiftR or the unified shift, depending on which is more convenient for the type in question.

shiftR :: a -> Int -> aSource

Shift the first argument right by the specified number of bits (which must be non-negative). Right shifts perform sign extension on signed number types; i.e. they fill the top bits with 1 if the x is negative and with 0 otherwise.

An instance can define either this and shiftL or the unified shift, depending on which is more convenient for the type in question.

rotateL :: a -> Int -> aSource

Rotate the argument left by the specified number of bits (which must be non-negative).

An instance can define either this and rotateR or the unified rotate, depending on which is more convenient for the type in question.

rotateR :: a -> Int -> aSource

Rotate the argument right by the specified number of bits (which must be non-negative).

An instance can define either this and rotateL or the unified rotate, depending on which is more convenient for the type in question.

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