Copyright | (c) The University of Glasgow 2001 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | libraries@haskell.org |
Stability | experimental |
Portability | portable |
Safe Haskell | Safe |
Language | Haskell2010 |
Unsigned integer types.
- data Word
- data Word8
- data Word16
- data Word32
- data Word64
- byteSwap16 :: Word16 -> Word16
- byteSwap32 :: Word32 -> Word32
- byteSwap64 :: Word64 -> Word64
Unsigned integral types
8-bit unsigned integer type
16-bit unsigned integer type
32-bit unsigned integer type
64-bit unsigned integer type
byte swapping
byteSwap16 :: Word16 -> Word16 Source
Swap bytes in Word16
.
Since: 4.7.0.0
byteSwap32 :: Word32 -> Word32 Source
Reverse order of bytes in Word32
.
Since: 4.7.0.0
byteSwap64 :: Word64 -> Word64 Source
Reverse order of bytes in Word64
.
Since: 4.7.0.0
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
negate
should not raise an error on negative arguments. - For coercing between any two integer types, use
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. - It would be very natural to add a type
Natural
providing an unbounded size unsigned integer, just asInteger
provides unbounded size signed integers. We do not do that yet since there is no demand for it. - The rules that hold for
Enum
instances over a bounded type such asInt
(see the section of the Haskell report dealing with arithmetic sequences) also hold for theEnum
instances over the variousWord
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.