Portability | portable |
---|---|
Stability | experimental |
Maintainer | libraries@haskell.org |
Safe Haskell | Trustworthy |
- class (Eq a, 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
- unsafeShiftL :: a -> Int -> a
- shiftR :: a -> Int -> a
- unsafeShiftR :: a -> Int -> a
- rotateL :: a -> Int -> a
- rotateR :: a -> Int -> a
- popCount :: a -> Int
Documentation
class (Eq a, 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
.
Bitwise "and"
Bitwise "or"
Bitwise "xor"
complement :: a -> aSource
Reverse all the bits in the argument
shifts shift
x ix
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.
rotates rotate
x ix
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 i
is a value with the i
th bit set and all other bits clear
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 n
th bit of the argument is 1
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
.
Return True
if the argument is a signed type. The actual
value of the argument is ignored
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.
unsafeShiftL :: a -> Int -> aSource
Shift the argument left by the specified number of bits. The
result is undefined for negative shift amounts and shift amounts
greater or equal to the bitSize
.
Defaults to shiftL
unless defined explicitly by an instance.
Shift the first argument right by the specified number of bits. The
result is undefined for negative shift amounts and shift amounts
greater or equal to the bitSize
.
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.
unsafeShiftR :: a -> Int -> aSource
Shift the first argument right by the specified number of bits, which must be non-negative an smaller than the number of bits in the type.
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.
Defaults to shiftR
unless defined explicitly by an instance.
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.
Return the number of set bits in the argument. This number is known as the population count or the Hamming weight.