Chapter 15
Data.Bits

This module defines bitwise operations for signed and unsigned integers.

class Num a => Bits a where

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 および shiftR)), (rotate or (rotateL および rotateR)), bitSize および isSigned.

Methods

(.&.) :: a -> a -> a

Bitwise ”and”

(.|.) :: a -> a -> a

Bitwise ”or”

xor :: a -> a -> a

Bitwise ”xor”

complement :: a -> a

Reverse all the bits in the argument

shift :: a -> Int -> a

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 および shiftR, depending on which is more convenient for the type in question.

rotate :: a -> Int -> a

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 および rotateR, depending on which is more convenient for the type in question.

bit :: Int -> a

bit i is a value with the ith bit set and all other bits clear

setBit :: a -> Int -> a

x ‘setBit‘ i is the same as x .|. bit i

clearBit :: a -> Int -> a

x ‘clearBit‘ i is the same as x .&. complement (bit i)

complementBit :: a -> Int -> a

x ‘complementBit‘ i is the same as x ‘xor‘ bit i

testBit :: a -> Int -> Bool

Return True if the nth bit of the argument is 1

bitSize :: a -> Int

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 -> Bool

Return True if the argument is a signed type. The actual value of the argument is ignored

shiftL :: a -> Int -> a

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 -> a

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 -> a

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 -> a

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.

instance Bits Int

instance Bits Int8

instance Bits Int16

instance Bits Int32

instance Bits Int64

instance Bits Integer

instance Bits Word

instance Bits Word8

instance Bits Word16

instance Bits Word32

instance Bits Word64

instance Bits WordPtr

instance Bits IntPtr

instance Bits CChar

instance Bits CSChar

instance Bits CUChar

instance Bits CShort

instance Bits CUShort

instance Bits CInt

instance Bits CUInt

instance Bits CLong

instance Bits CULong

instance Bits CLLong

instance Bits CULLong

instance Bits CPtrdiff

instance Bits CSize

instance Bits CWchar

instance Bits CSigAtomic

instance Bits CIntPtr

instance Bits CUIntPtr

instance Bits CIntMax

instance Bits CUIntMax